Does order matter for composite primary key in Oracle or any database?

Question: I have a Composite Primary key which is combination of Column1, and Column2.  What would be the difference if I have Composite key with Column2, and Column1.  Does it even really matter which order you set columns?
Comment: Read here: http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:5671539468597
Comment: Or read this: http://use-the-index-luke.com/sql/where-clause/the-equals-operator/concatenated-keys
Answer: It does, but perhaps not in the way you might expect.
Given col1 and col2, people's initial instinct is to put the more selective column first.
But, that's almost always irrelevant.
First, you need to consider how the index will be used in your SQL statements.  If some SQLs only specify col1, then col1 should probably be first.  If all SQLs will always specify both columns in the where predicate, then it doesn't matter which comes first.
But, what if most of the SQLs specify both col1 and col2, and a few provide only col1 or col2?
Well, in that case, the least selective column should (probably) go first.  There are two reasons for this.  First, if the least selective goes first, then, for those queries where only the second column is specified in the predicate, Oracle will be more likely to do an INDEX SKIP SCAN, if the leading column is not very selective.  Second, by putting the less selective column first, you'll be more likely to be able to take advantage of index compression.
Hope that helps.
Answer: This is really a question of how your users will be accessing the data.
By composite key - I am assuming these columns to be the unique identifier for accessing rows in this table. If so this creates a unique index over these columns.
Traditionally, the most selective columns are used first in an index. And it would make sense for this approach to be taken to offer the best in performance.
However, where index hotspots have been detected - the index can be reversed.
The index may also be affected if either of the columns are missing in the WHERE clause when accessing data.


What type of tea should I use to make Thai Iced Tea?

Question: I love the sweet iced tea you get at Thai restaurants, and want to make my own at home.  I used to buy a concentrated solution online (added water and half and half), but they discontinued it.  I'm not sure what type of tea is used, but it is reddish in color and has hints of coconut taste in it. Cheers!
Comment: Straight-up recipe requests are off-topic here as per the [faq], and there are plenty of Thai iced tea recipes online. Have you tried any?
Answer: I currently live in Thailand and there is really only 1 brand that's used (If there is another brand I've never seen anyone use it!) nationwide by all the street vendors to make traditional Thai Ice Tea and that's this one...

I don't know the name of it but I'm pretty sure it's just Number One Brand. I'll confirm the name when I get chance!
Comment: BTW, if you have any asian markets nearby you shouldn't have any trouble finding some.
Comment: Found it on Amazon easily, we tried both half and half and condensed milk. Half and half is faster, but condensed milk tastes better, even though it takes some stirring to get it all to dissolve.
Answer: Most of the recipes I've seen don't have any coconut in them. The most common way to get that flavor would be to use coconut milk instead of some (or even all) of the dairy. This could be pretty rich, but given that you're using half-and-half already, probably won't bother you too much.
As for the type of tea, it really depends on what you have available. If you're lucky, you have a well-stocked grocery store or an Asian one, and you can just get traditional Thai tea. If not, you want black tea. Either way, it should be brewed strongly.
Any vibrant color is generally just from food coloring, not the tea itself. If you can buy Thai tea, it might well have the color in it. If you're using some kind of plain black tea, reproducing the color would probably mean adding a little bit of red and yellow food coloring.
Answer: The kind of tea you want is Jasmine. It has a nice floral note to it that is used in Thai Ice Tea, but can taste slightly coconut-y. I bought some bottled jasmine tea from a local store, added some sugar and heavy cream over ice, and it tasted just like the tea you'd get from a Thai place.
Answer: Celestial Seasonings makes a Thai Coconut Chai which may get you a little closer in flavor and color. Coconut milk instead of half and half sounds good, too.
Answer: As far as I can determine, there is no such thing as "Thai" tea. It's very strongly brewed black tea, and the color (originally) came from Tamarind pulp. In the US, where we don't deal well with tamarind, it's likely to be food coloring. The "secret sauce" is a combination of orange blossom water, star anise, and sometimes other spices like cinnamon or cassia, all sweetened with evaporated milk and sugar. The actual recipe is usually pretty well guarded, so experiment.
Comment: There certainly is such a thing as Thai tea. Sure, there are varieties, and you can start from plain black tea, or get it pre-spiced/colored, but, well, look at the picture in Eddy's post. (I've seen other kinds in stores here too.)


Add a wordpress blog to my website having users

Question: I have a php/mysql based site with users segregated into different groups... i want to add blogging system to it so that each group has its own blog which can be authored by users who are designated to administer that group and can be read by each user of that group... how can this be done?
Answer: I haven't been working with WordPress too much, so there may be someone who can give you more details. But here's what I've come to understand:
If you want to have multiple blogs (one for each group) then you need to EITHER:

Filter the posts according to who is logged in
Operate a multi-site WordPress install

The former could be done as part of the plugin that I will explain later, the latter can be done using WordPress core - although it will not be able to dynamically create these new blogs if a new user group were added.
As far as having users logged into your own website recognized as authenticated in WordPress, you would need a plugin that loads after WordPress's own user authentication. If you load before WordPress's user authentication then you would verify they were logged in and WordPress would immediately over-write this saying that they were not. The init hook would work best for this (http://codex.wordpress.org/Plugin_API/Action_Reference)
add_action('init', 'load_my_user');
function load_my_user(){
    /* Determine the user ID and name of who is logged in*/
    /* You should know how to do this for your website */
    wp_set_current_user($id, $name);
}

If the user does not exist then WordPress should create it, so if user registration is disabled in WordPress (done via the Dashboard) to prevent an ID collision then your users should be able to immediately take advantage of this and log in.
As for filtering the returned posts according to group, I'm not entirely sure how that would work, but I suspect it would involve the pre_get_posts or posts_selection hook. In fact, it may even be possible to do this using WordPress core features. I'm really not clear on this much. But the above should help you at least log in to WordPress with your current user database =)
Answer: Is that "php/mysql based site" a self-done script or do you use a finished software. In the latter case, there maybe exists a connector to Wordpress. But Wordpress isn't really pluggable into other CMS'.
One other way I can think of, is into "fooling" Wordpress, by replacing its user tables (using the same database as your website) with views of your user-tables. SO it really works on your users, with their respective rights, while all blogging content would be saved to Wordpress' own tables.
Though, using Wordpress itself as a CMS, and then also using its blogging-features would be the "best" way (if you have a chance to change your underlying system and migrate all the old pages to Wordpress).


Sources for Abraham's Link to Safa and Marwa

Question: I'm looking for which Islamic sources explain the story of Abraham, Hagar, and Ishmael's affair with Safa and Marwa.
Online, every site I can find tells the story of Abraham leaving Hagar and Ishmael, and her running back and forth 7 times, but there aren't any sources cited.
Thanks
Answer: Sahih al-Bukhari 3365 narrates the story which mentions Safa and Marwa.

Narrated Ibn 'Abbas: When Abraham had differences with his wife),
(because of her jealousy of Hajar, Ishmael's mother), he took Ishmael
and his mother and went away. They had a water-skin with them
containing some water, Ishmael's mother used to drink water from the
water-skin so that her milk would increase for her child. When Abraham
reached Mecca, he made her sit under a tree and afterwards returned
home. Ishmael's mother followed him, and when they reached Kada', she
called him from behind, 'O Abraham! To whom are you leaving us?' He
replied, '(I am leaving you) to Allah's (Care).' She said, 'I am
satisfied to be with Allah.' She returned to her place and started
drinking water from the water-skin, and her milk increased for her
child. When the water had all been used up, she said to herself, 'I'd
better go and look so that I may see somebody.' She ascended the
Safa mountain and looked, hoping to see somebody, but in vain. When she came down to the valley, she ran till she reached the
Marwa mountain. She ran to and fro (between the two mountains) many times. They she said to herself, 'i'd better go and see the state
of the child,' she went and found it in a state of one on the point of
dying. She could not endure to watch it dying and said (to herself),
'If I go and look, I may find somebody.' She went and ascended the
Safa mountain and looked for a long while but could not find anybody. Thus she completed seven rounds (of running) between Safa
and Marwa. Again she said (to herself), 'I'd better go back and
see the state of the child.' But suddenly she heard a voice, and she
said to that strange voice, 'Help us if you can offer any help.' Lo!
It was Gabriel (who had made the voice). Gabriel hit the earth with
his heel like this (Ibn `Abbas hit the earth with his heel to
Illustrate it), and so the water gushed out. Ishmael's mother was
astonished and started digging. (Abu Al-Qasim) (i.e. the Prophet)
said, "If she had left the water, (flow naturally without her
intervention), it would have been flowing on the surface of the
earth.") Ishmael's mother started drinking from the water and her milk
increased for her child . Afterwards some people of the tribe of
Jurhum, while passing through the bottom of the valley, saw some
birds, and that astonished them, and they said, 'Birds can only be
found at a place where there is water.' They sent a messenger who
searched the place and found the water, and returned to inform them
about it. Then they all went to her and said, 'O ishmael's mother!
Will you allow us to be with you (or dwell with you)?' (And thus they
stayed there.) Later on her boy reached the age of puberty and married
a lady from them. Then an idea occurred to Abraham which he disclosed
to his wife (Sarah), 'I want to call on my dependents I left (at
Mecca).' When he went there, he greeted (Ishmael's wife) and said,
'Where is Ishmael?' She replied, 'He has gone out hunting.' Abraham
said (to her), 'When he comes, tell him to change the threshold of his
gate.' When he came, she told him the same whereupon Ishmael said to
her, 'You are the threshold, so go to your family (i.e. you are
divorced).' Again Abraham thought of visiting his dependents whom he
had left (at Mecca), and he told his wife (Sarah) of his intentions.
Abraham came to Ishmael's house and asked. "Where is Ishmael?"
Ishmael's wife replied, "He has gone out hunting," and added, "Will
you stay (for some time) and have something to eat and drink?' Abraham
asked, 'What is your food and what is your drink?' She replied, 'Our
food is meat and our drink is water.' He said, 'O Allah! Bless their
meals and their drink." Abu Al-Qa-sim (i.e. Prophet) said, "Because of
Abraham's invocation there are blessings (in Mecca)." Once more
Abraham thought of visiting his family he had left (at Mecca), so he
told his wife (Sarah) of his decision. He went and found Ishmael
behind the Zamzam well, mending his arrows. He said, "O Ishmael, Your
Lord has ordered me to build a house for Him." Ishmael said, "Obey
(the order of) your Lord." Abraham said, "Allah has also ordered me
that you should help me therein." Ishmael said, "Then I will do." So,
both of them rose and Abraham started building (the Ka'ba) while
Ishmael went on handing him the stones, and both of them were saying,
"O our Lord ! Accept (this service) from us, Verily, You are the
All-Hearing, the All-Knowing." (2.127). When the building became high
and the old man (i.e. Abraham) could no longer lift the stones (to
such a high position), he stood over the stone of Al- Maqam and
Ishmael carried on handing him the stones, and both of them were
saying, 'O our Lord! Accept (this service) from us, Verily You are
All-Hearing, All-Knowing." (2.127)
Sahih al-Bukhari 3365 https://sunnah.com/bukhari:3365


What are natural growth rates for incoming and outgoing links?

Question: Appears to be no more than 10-15% per month, is that correct? Also, along the same lines, what the max amount of outbound link a site can start out with and not be canned as spam.
Answer: Natural grow rates for incoming links?
What do you think they are, plants?
There is no such thing as "natural" when dealing with incoming links, if you create quality content that is considered linkable then it will be linked. If not, it wont.
The "natural rate" of your outgoing links from your site is just as fast as you can type ... there is no such thing as X outgoing links per month.
I don't mind getting flagged, but this question is just so stupid it amazes me.
How can you even count links using percents?
Or is this deliberate flame bait?
Ok, now the proper answer:

NO, it is not correct. Several viral campaigns had millions of incoming links created to them in a matter of hours/days.
Infinite number of outgoing links will not be considered spam if they are placed in quality content. It is not the number of links that is considered spam, it is the quality of the content.

To see a large amount of outgoing links, see wikipedia as example. If you would build a time machine and transfer wikipedia into a time it didn't exist, and it would just appear out of nowhere - then the links on it will NOT be considered spam. Because the content is of high quality.
Comment: As you would say, "Prefer answers with experience or links to trustworthy material, over speculations, assumptions and gut feelings."
Answer: It really depends on the industry some industries are very web savvy and get lots of links easily where others are not. Majestic SEO has a really neat tool that allows you to compare backlinks over time of different domains.
http://www.majesticseo.com/reports/compare-domain-backlink-history
The types of links also impact how Google views them if you are doing something that generates a lot of news and Google sees a lot of trusted news sources covering the topic and a spike in searches for the topic they would expect to see a lot of new backlinks quickly whereas if you are submitting to 1,000 directories a day and getting no other links that would throw up red flags.
Comment: Thanks, +1 and selecting you as the answer -- again, thanks for sharing!


Cameras that can be used in the rain?

Question: What cameras (DLSR & lenses, Mirrorless or P&S) can be used when its raining cats and dogs without any kind of special rainproof accessories to protect them?
Comment: Are you looking to buy something? Are you just shooting in inclement weather? Maybe a GoPro would suit you? I don't understand what the reason for this question is, maybe if you could explain the use case the answers would be better.
Comment: There are some truly excellent rain covers out there for DSLRs that are worth their weight and minimize the amount of drying you have to do after you've come back in from the weather.  Is there a reason accessories are off the table?
Comment: I have a 5DMII and I'm worrried about getting it wet when it looks like it is going to rain so I was thinking of getting a used 1DsMIII and it is supposed to be weather sealed when used with a weather sealed L lense and filter.  But does that mean it can be used when it is raining really bad?
Comment: You should consult the manuals for whatever you're buying.  Weather sealed or not, I'd still make sure it was covered, because operating the controls is a lot easier when they're not sopping wet.
Comment: yes you can use a 1Ds mkIII if it's raining really hard. @Blrfl I've never had a problem operating the camera when it's wet - the hand grip stays grippy, afnd you can wipe the water droplets off.
Answer: There are plenty such models with some in every category.
The highest resistance to inclement weather are waterproof cameras which are all point-and-shoot model with a sealed non-extending lenses. These can even go underwater between 3 to 12m for a minimum of 60 minutes.
Weather-poof cameras are sealed against splashes in any direction but are not protected against water pressure. For an interchangeable lens camera, a weather-sealed lens must be used to make the whole thing weather-sealed. In some limited cases you need to add a filter to the lens to complete the seal.
Weather-proof lenses are available for various mounts but some like Sony Alpha and Micro Four-Thirds mounts have an extremely limited number of weather-proof lenses. There are none  for the Fuji X mount. Olympus makes a weather-sealed Four-Thirds to Micro Four-Thirds adapter so you can use weather-sealed Four-Thirds lenses on Micro Four-Thirds cameras.
There are several cameras and a handfull of DSLRs - all from Pentax - which are also freezeproof which makes them suitable for extended usage at sub-zero temperatures. Living in Canada and having owned all such DSLRs, I can attest to this. I have also taken my K-7 and K-5 in heavy rains and in several desert sand-storms and have had no trouble rinsing them (with lens attached) under the tap to clean them after. Needless to say, I am not worried about rain :) Incidentally, Pentax also makes the cheapest weather-sealed DSLRs and cheapest weather-sealed lenses.
Answer: I can vouch for the Canon 1 series, I've used both the 1Ds mkII and 1D mkIV for extended periods in the driving rain. You need a weather sealed lens, most L series are, you can usually tell by if there's a rubber skirt around the mount. I don't bother with a filter as the lens hoods on the primes I shoot with a really deep and stop water going anywhere near the front element (just don't point the camera up). Other than that you're good to go, these bodies can cope with pretty much everything except submersion.
I should note that other manufacturers offer weather sealed cameras/lenses too, but I can't personally vouch for them.
Answer: Professional level DSLR cameras many times can be used without issues in the rain. Some of them require a filter to complete the weather sealing of the lens. There isn't necessarily a "kind", just look for "weather sealing" and to what degree it is weather sealed. Note, you would want a lens and a DSLR body that is weather sealed, not just one or the other.
For point and shoot cameras, I would recommend any waterproof camera such as a Nikon AW100 or similar.
Answer: The necessity for waterproofness when working in rain is lessened by something obvious but important: it's raining. The rain gets on the front element/filter of the lens and leaves streaks or rain drops in your photo. The solution? Dry the element and try to keep it dry. How do you do that? Easiest thing is to keep the camera dry by sliding it into your jacket or using a raincoat of some sort. In the end, a weatherproof/waterproof camera is important to letting you work in those conditions for the peace of mind it brings, but practically, the solution is still to care for the camera and give it a dry spot.

Cameras that can be used in the rain?


How can I perform an Apple Hardware Test without my original install media?

Question: I have a 2007 MacBook that I'd like to perform an Apple Hardware Test on, but I don't have the original install media. I have a Snow Leopard install DVD, but rebooting and holding down D does not launch the test. Short of going to the Apple Store, is there any way to test the hardware?
Answer: I've never been able to figure out why this function seems so unreliable - holding D for diagnostics doesn't seem to work for me in practice. I wish I had a better explanation than "many models don't have this and even the ones that do, this isn't something I can count on."
I have come to rely on AHT that are available for authorized Apple technicians to download so you might be able to get help from one closer than an Apple Store - http://www.apple.com/buy/locator/service/
Apple will usually run a very good test for free as past of a genius bar appointment, and both Apple and Authorized Service will usually check a mac in for diagnostics under coverage for no charge. Out of warranty, expect to pay $39 to $85 for a diagnostic.
Lastly, you can order replacement media if yours are misplaced from Apple. 800-APL-CARE
Answer: The only thing you can do with the Snow Leopard disk is to boot to it by holding "C". You could also hold down the option key and pick the disc to boot off of.
Then you can go to the Utilities Menu>Disk Utility and run "Verify/Repair Permissions" and "Verify/Repair Disk". One or both of these tests may yield some information.
Comment: I appreciate the suggestion, but it's not a disk problem I'm trying to isolate.


Camping stove on a plane?

Question: Can I bring a camping stove (without fuel) on a (domestic or international) jet, either in checked baggage, carry-on, or some other means?
Comment: Note that different airlines have different policies on what you can bring on.  It'd be worth adding where you're hoping to travel, and which airline (if you know it).
Answer: You can bring it in a checked luggage, just make sure there is no fuel or fuel residue. I do not recommend trying carrying it in a carry-on baggage even if it has no fuel, this will delay you at the security check and most likely they will reject it or maybe confiscate it. If it has fuel smell it will be rejected even if it is in checked luggage.
Please note, fuel is not allowed either in carry-on or checked luggage even if it is in a proper containers. It is considered hazardous material. If you suspect that it has some or even  very little fuel do not take it for your own safety and the safety of the other passengers, it is dangerous and may cause a big problem even it is in checked luggage.
For more information:
Prohibited Items
Answer: Go for a canister propane/butane stove, not a liquid fuel one. I have travelled a lot with my JetBoil in a carry-on bag. 2 years ago they sometimes asked questions and you had to explain there is no fuel inside by design, this year I was asked no questions at all.
When you arrive, buy a couple of fuel canisters in any outdoor store and you are all set.
However, sometimes you just can't buy canisters at your destination (e.g. only petrol or kerosine are available). They you have to use a multifuel or liquid fuel stove. Use one where fuel bottle is a separate part, not integrated into main body. Make sure the bottle is empty and doesn't smell and put it into checked luggage. Bottles do not attract much attention (tried it a couple of times with no problems).
Answer: I specifically bought one with this in mind. The stove comes with a handy travel bag of its own. I have no clue how they are called, but I added two photo's of mine. I bought it at a specialized camping shop. Never, ever bring the fuel with you on the plane.
So far I took it with me on roughly 5 journeys in the last 10 years.
What I did so far is bought mainly alcohol as fuel. Before going back, I made sure all remaining fuel residued were burned properly, after which I thoroughly cleaned it with detergent, making sure no smell of alcohol remained.
I was told making small holes on top part of a can would create more or less the same stove and that it is common practice in military training to make these type of stoves out of cans. I never tried that though.
Comment: Cool idea, building your own stove. Found this link about it http://www.wikihow.com/Make-a-Simple-Beverage-Can-Stove
Answer: After traveling successfully with  canister stoves multiple times, I had my MSR canister stove (the tiny burner attachment, not the fuel) taken away by Jet Blue at LAX from my checked luggage. (They asked me if I had a stove when I checked in and I of course answered honestly). Their regulations apparently prohibit all camping stoves. So don't fly Jet Blue and double check each airline you plan on flying

Camping stove on a plane?


Plugin for editing options on multisite?

Question: does anyone know of a plugin for mass editing of settings on a multisite installation? Something like Plugin Commander for Settings?
Answer: I'm not sure if this really answers your question, but have you looked at CheezCAP?
It's a framework to allow a theme to register options and settings panels on the fly, so that on a multi-site install you can more easily add options to the themes across the board, and manage the settings on a site-by-site basis.
Doesn't quite do what you're looking for, though...
Answer: i think this is what you looking for:
http://wordpress.org/extend/plugins/yd-wpmu-sitewide-options/


Impact of Mathew Garrett's Secure GRUB Bootloader on UEFI Secure Boot

Question: My eyebrows rose with Matthew Garrett announcing his Secure GRUB Bootloader less than three hours after no longer being a Red Hat employee.  This work and its impact on the trust chain design of the UEFI secure boot now being implemented on Windows 8 configured hardware has had me puzzled for the last six months. Can one shim the trust chain without significantly damaging the overall concept of secure boot?
Comment: The enforced UEFI secure boot as microsoft is trying to enforce it's not how it's designed anyway. It's originally designed for the administrators of a system to configure and control. Not OEMs.
Answer: This depends what you mean by "the overall concept of secure boot".
Pretty much all secure boot systems have several components, starting with one in ROM and ending with an operating system or even programs within that operating system. A typical boot chain is ROM → OEM bootloader → OS bootloader → OS kernel → OS startup programs. A typical secure boot chain has each element of the chain verify the signature of the next element. Each link may involve a different authority to decide which signatures are allowed (the chipset maker, the OEM, the OS vendor, …).
In the case of Matthew Garrett's shim, the path is: … → UEFI → shim → OS bootloader. The shim is signed with a signature that the UEFI BIOS accepts. The code of the shim decides what is allowed at the next stage. The shim is designed so that it allows anyone in physical possession of the device to provide their own signing key for the next stage.
If you think that secure boot is about the owner of the device controlling what the device can run, this is perfectly normal: the end user is in ultimate control of the software that is executed on the device. If you think that secure boot is about the device manufacturer locking the software against modifications by the end user, then allowing someone like Matthew Garrett to participate in the secure boot chain breaks secure boot.
The background is that Microsoft, in part via the UEFI specification, has been pushing for OEMs to activate secure boot on all platforms running Windows 8, allowing only OEM-approved operating systems (with Microsoft having a signing key). On PC-style platforms, Microsoft has signed a shim which allows other operating systems to be loaded, allowing other operating system vendors to provide a secure boot. On ARM platforms shipping with Windows 8, Microsoft has retained the only signing key, locking the user into Microsoft's operating system.
Comment: Thanks, I will let 24 hours pass but it appears you get the check as the answer is outstanding.
Comment: @Gilles - One should point out that Microsoft just wants `Secure Boot` enabled.  At least on x86-64 platform its not about control over the OEM.  If Microsoft didn't require `Secure Boot` to be enabled nobody would use the feature despite it being able to solve problems that do exist.
Answer: This is using Trusted Platform Module to defeat the Evil Maid Attack.  In short this is to insure that your bootloader hasn't been tampered with,  which could undermine an encrypted file system.
Comment: For info: http://testlab.sit.fraunhofer.de/downloads/Publications/Attacking_the_BitLocker_Boot_Process_Trust2009.pdf
Comment: How will this defeat the evil maid attack, isn't it exactly the opposite? I quote: ["any bootloader signed with that key will then be trusted by shim"](https://mjg59.dreamwidth.org/20303.html). This is step 1 of the [evil maid attack scenario](https://www.schneier.com/blog/archives/2009/10/evil_maid_attac.html) you cite.


Maintaining referential integrity between a mobile client and a server

Question: So I have a relatively simple system. A mobile client creates records in a sqlite database that I would like to have synced to a remote SQL server (that is shared with other mobile clients). So when I create a new record in the phone's sqlite table, I then push that change to my remote service through a RESTful API. The problem I'm having, is how do I order the primary keys so that there isn't collisions in the data (i.e. a record in the phone has the same primary key as a completely different record on the server). What is the usual "best practice for referencing the record on the client, and for referencing the same record on the server?
Comment: The over-arching idea, would be that the client acts as a cache for the web server, with changes being created in the client, then pushed to the web server
Answer: The normal practice is to structure your database with uniqueidentifier keys (sometimes called UUIDs or GUIDs).  You can create them in two places without realistic fear of collision.
Next, your Mobile app needs to sync "fact" tables from the server before you can create new rows.  When you create new rows, you do it locally, and when you sync again, new rows are added to the server.  You can do the same thing with updates and deletes too.
To track inserts you need a Created timestamp on your rows.  To track updates you need to track a LastUpdate timestamp on your rows.  To track deletes you need a tombstone table.
Note that when you do a sync, you need to check the time offset between the server and the mobile device, and you need to have a method for resolving conflicts.  Inserts are no big deal (they shouldn't conflict), but updates could conflict, and a delete could conflict with an update.
There are frameworks to handle this kind of thing, such as Microsoft Sync Framework.
Comment: is sync framework still alive
Answer: I bet that you absolutely, without question cannot have referential integrity between the two.  Specifically, do your users expect the mobile application to work when it is disconnected?
There are two practices for this:
One is to create "provisional" records on the client, and then when you sync them to the server have the central system assign the ID.  The client can update the local record to reflect that.
The other is that you distribute ID creation in a way that (normally probabilistically) allows clients to create the ID without collisions.
For that, go to UUIDs - v4 are fairly unlikely to collide.
Otherwise, consider something that puts the unique mobile device ID in the record ID.  So, your record ID might be ${imei}-${local sequence number} or something, where the IMEI ensures uniqueness, and the local sequence number is just a normal sequential database ID.
Answer: In addition to Daniel Pittman's answer, one possibility would be for the server to assign each client a unique client ID, and make the Client ID a part of the primary key.
Answer: I have the same issue with a project i am working on, the solution in my case was to create an extra nullable field in the local tables named remote_id. When synchronizing records from local to remote database if remote_id is null, it means that this row has never been synchronized and needs to return a unique id matching the remote row id.
Local Table            Remote Table

_id (used locally)
remote_id ------------- id
name      ------------- name

In the client application i link tables by the _id field, remotely i use the remote id field to fetch data, do joins, etc..
example locally:
Local Client Table       Local ClientType Table      Local ClientType
                         _id
                         remote_id
_id -------------------- client_id
remote_id                client_type_id -------------- _id
                                                      remote_id
name                    name                          name

example remotely:
Remote Client Table      Remote ClientType Table      Remote ClientType
id -------------------- client_id
                        client_type_id -------------- id
name                    name                          name

This scenario, and without any logical in the code, would cause data integrity failures, as the client_type table may not match the real id either in the local or remote tables, therefor whenever a remote_id is generated, it returns a signal to the client application asking to update the local _id field, this fires a previously created trigger in sqlite updating the affected tables.
http://www.sqlite.org/lang_createtrigger.html
1- remote_id is generated in the server
2- returns a signal to client
3- client updates its _id field and fires a trigger that updates local tables that join local _id
Of course i use also a last_updated field to help synchronizations and to avoid duplicated syncs.


AVID Certification

Question: Has anyone here gotten AVID certified at some level for Pro Tools?  Have you found it helpful in finding work? Was it worth the time and money?  I have been using Pro tools for well over 13 years and keep being told I will need to start at Pro Tools 101 to be certified (It is very expensive and time consuming).  Have any of you tested out of required classes and still been AVID certified?
Comment: I know a few people with some qualifications but I've never got around to asking why. I looked them up and like you was completely put off by having to start from scratch. Plus having to pay all that money which is quite a lot considering it's a corporate qualification.
Answer: Probably only of any worth if your main aim it to become a tutor on those courses
Answer: Heyo - most people here probably know that after working for Avid happily for over 7 years (left easly last year), if you cut me my blood looks a litttttle bit purple, but bias in context and having just taught the entire curriculum at UTS:Proschool in Sydney over the last 6 weeks I can pass on some observations on the current curriculum if you want them.
Theyre up to rev 5 or 6 of the curriculum atm, the second PT9 revision. So its been changing quite a bit over the last 2 years. Yes you still get two questions the same popping up in exams every now and again, but the questions with false answers have been mostly weeded out.
Exam, pffexam, whatever, if you want a piece of paper, you can sit it, but the course should be more than just reading the book/having the book read to you and sitting a multiple choice exam. The job of the teacher is to impart the concepts and workflows and context of the features you are trying to master.
PT101- easy course
Pt110 - massive course if you try to do it in 3 days, elastic audio in depth, starting into automation, all the midi features
PT201 - intro of trim and write to all and HD architecture and the 48 bit mixer, signal flow discussions, editing automation
210M - beat detective, trims, VCAs, drum editing workflows, sync concepts
210P - machine control, VCAs, preview, write tos, trim, satellite tech,
310M and 310P more detail on automation modes, more shortcuts you are expected to know, more assumed knowledge and pracs dont walk you through everything like they do in earlier courses. only a multi choice exam now but the old gauntlet pracs are part of the course
Basically - if youre in here, on this forum, you probably care about your craft, are self-motivated and read the manual, watch videos etc to further your skills. You could do a course with a good teacher who you respect and get something more out of it, fleshing out holes in your knowledge you may not realise you have, or you could get a teacher who reads from the book, hasnt much real world experience and doesnt add much to the experience.
Pick your school and teacher wisely and it could well be worth your while.
Lastly - if you care about exams, you have to do them all in sequence, if you just want the knowledge, some schools are prepared to accept experienced operators into advanced classes on the understanding they arent interested in certification exams, just the book and learning experience, so you may not have to start at 101 everywhere.
Comment: Just curious, why did you leave and what are you doing now?
Comment: Reasons I left? I was lucky enough to have a gig where although I was often passing on info to clients, clients were often mentoring me as well and I learnt a tonne of new skills - however, I didnt have the creative opportunities to use them - frustrating.
Also, my "mandate" was sales but I loved training.
Lastly, I got married and my wife and I are thinking of starting a family sometime soon and I didn't want to feel pressured to keep a high paid job and never chase a dream. So I left, opened a premix room, train/consult part time and love it all. Left on good terms.
Answer: Try to see if you can enter at a more advanced level. It can go agonizingly slow with the newer users in those classes when you're operating at a level like you are.
Does anyone know if you can shortcut it and just take the test without doing the classes? That would be ideal...
I've studied the Pro Tools manual 4 times through:
version 5, 6, and 7 twice, so going to a class and starting from scratch to get an asterisk next to my name on a resume is a waste of money.
But, in the end, I think that high quality products and samples are a much better thing to show on your resume than an AVID cert IMHO.
Answer: I went through a bit of the training a while back and found that it gave me no advantage.  In a intensive ProTools environment or facility, I can certainly see some of the training coming in handy - more of a technical understanding of PT in larger scale/professional environments.
I certainly didn't need the training to get where I'm at.  By no means whatsoever am I bragging, but spend time and learn the environment.  They're expensive classes that give you no real world experience.  And good luck!
Answer: I am Pro Tools certified at the 210 level.  It has done nothing to truely advance my career.  The books are a great resource for a beginner, and you should strive to know PT inside and out, but paying for "classes" was a waste in my opinion.
Answer: I don't know if they've fixed them, but their tests were all screwed up a few years ago. Some questions had multiple correct answers, some had none, and the test itself is randomly generated from a pool of questions. The big problem with that last one was that the same question would pop up multiple times (including those with multiple/no correct answers).
Answer: If you are new to Pro Tools then the 101 book is worth buying, you can purchase it from Amazon.
Answer: I got certified as part of my educational initiation to sound work. In my experience, being PT certified is like telling people you were an Eagle Scout; folks might be impressed that you put time, effort, and money into achieving such a title, but that doesn't mean you can do the job better than the other guy. If my work were being weighed against another sound editor of equal talent, I imagine it could serve as a tiebreaker, but not much more.
Answer: I have the 210 post certification. Have had none questions about this when getting jobs.
Infact a lot of my most recent jobs had to be done in Nuendo...
I think the books that comes with the courses is a great resource to have, but i wont be getting any other certificates.
Answer: Newbie here. I recently picked the brain of an audio director at a very well known video game company who advised me to get PT post certified if I wanted a leg up in the audio post job market. Now I'm reconsidering things after reading this thread! Being that my only experience is working on small projects at home for fun, my plan was to hopefully become expert certified in post production at an Avid training school >> intern at a post house >> work on small indie projects for little to no money >> work my way up from there.
Should I reconsider my strategy if certification has no real pull when it comes to landing a job in this business?
Answer: I have the 101 and 210 cert (got them during school), and it has never come up in an interview. I think that it definitely doesn't hurt to have on the resume, but all in all it probably wouldn't have been worth the effort if it wasn't already part of the course material I was working on.
Another thing to consider is that it probably varies in importance based on the field you're working in. I work in Game Audio and I would guess that it means just about the least here, and probably means a little more in post houses.
That being said, if you have 13+ years of ProTools use, you hopefully have a pretty nice demo reel going, and in my experience your demo reel should matter 100x more than any cert ever will.
hopefully that helps, best of luck!
-T
tldr; Have 210, hasn't made a noticeable difference...time could be better spent making a cool website or polishing your reel imo.
Answer: Speak softly and carry a big stick
Comment: that was an unpopular comment

AVID Certification


HREF Overflow: A tool to find cross-references between the trilogy sites

Question: Update 2010/04/25: A built-in feature like this seems to be around the corner. Note the "Linked" column on the right – this has been deployed exprimentally on Meta, but I suspect it won't be long before it's on all trilogy sites. So HREF Overflow is probably close to no-longer-relevant – thanks Jeff, I had just found the killer business model for making loads of money with this. No, really.
Update 2010/04/11: Now with data from the April data dump. This time, it also includes references made in comments (although you can hide these if you want to).
Update 2010/03/19: Since features like this have again been requested recently, I decided to finally update HREF Overflow. It's still based on the data dump, so no realtime data. But since I've simplified the process of updating the data, I'll be able to put the coming data dumps into it rather quickly. It now includes cross links between all four sites of the trilogy.

What is HREF Overflow?
When you have found an interesting question (say, "How do I do X?") on (e.g.) Stack Overflow, and you would like to read other similar question threads, one way to find such threads is to find out what other questions on the trilogy link back to "How do I do X". Which is what HREF Overflow does.
It shows you all* questions and answers on the trilogy that have links to the question you're interested in (or to one of its answers).
* All it knows about, that is. As mentioned, this isn't real-time data.
How can I use it?
There are two ways to query HREF Overflow. The first is to go to
http://hrefoverflow.appspot.com/SITE/QUESTION_ID
where QUESTION_ID is the numerical question id that appears in the URL of the question, and SITE is one of so, su, sf, and meta. For backwards compatibility, the SITE/ part is optional and defaults to so/.
The second way is to create a bookmark called "What links to this?" (or the like) that changes the location to http://hrefoverflow.appspot.com/referrer (there's a bookmarklet on the page that you can just drag to your bookmark bar).
When you request /referrer from HREF Overflow, it will pull out the information to the question you're coming from (unless, of course, your browser hides the referrer). You may also request /referer, so it's up to you whether orthographical or technical specs are more important to you.
Examples

Linking to the "what's missing" question: http://hrefoverflow.appspot.com/meta/42373
Linking to SO's version of The Daily WTF: http://hrefoverflow.appspot.com/so/434414
Linking to Jeff's blog panic question: http://hrefoverflow.appspot.com/su/82036
Comment: Clicked on star to make it glow.
Comment: Are links in comments also tracked?
Comment: @sth: Not currently. I'm thinking about adding that into the next version, although I seem to recall I had a good reason against this. Hmmm...
Comment: @sth: It now includes links in comments.
Comment: Yup, Jeff is advertising the new feature [quite aggressively](http://img.skitch.com/20100425-9ge53ffabw7u8swe2247xfujn.png) ;-)
Answer: No love for the rest of the trilogy sites?
One possible suggestion would be to hook your app up to the RSS feeds and index those posts, therefore you don't have a month old data.
Comment: **edit: this is no longer true - the dump is now available for all sites.** The dump only exists for SO, not the other sites, so getting the data would require scraping the question pages. But the RSS idea is good.
Comment: It now includes all four trilogy sites. Still no realtime data, though.
Comment: Ahhhh, didn't think of that.
Comment: I like the RSS idea, I'll look into that. The App Engine cronjobs must be good for something...
Comment: You should switch to the API now.


If $x, \log_{10}(x), \log_{10}\log_{10}(x)$ are in arithmetic progression, find the range of $x$.

Question:
If $x, \log_{10}(x) , \log_{10}\log_{10}(x)$ are in arithmetic progression, find the range of $x.$
(a) $0 < x < 1$
(b) $1 < x < 10$
(c) $10 < x < 100$
(d) $100 < x < 1000$

I have found the answer but I want a solution using logic without graph.
Comment: In case anyone is wondering, the progression turns out to be approximately $1.22802, 0.0892054, -1.04961$.
Comment: I re-formatted your question, please double check I didn't change anything.
Comment: What is the base of the log ?
Comment: @Belgi $\log_{10} $
Answer: To say that these numbers are in arithmetic progression is to say that
$$
2 \, \log_{10} x = x + \log_{10} \log_{10} x \, .
$$
Exponentiating this gives the equivalent equation
$$
x^2=10^x\log_{10} x \, .
$$
If $x<1$, the two sides of this equation have opposite sign, so the equation doesn't hold. Moreover, if $x > 10$,
$$
10^x \log_{10} x > 10^x = (\sqrt{10})^{2x} > (2^{x})^2 > x^2 \, ,
$$
so again the equation doesn't hold. So the only way it can hold is if $1<x<10$.
On the other hand, the function $f(x)=x^2-10^x \log_{10} x$ is continuous and has a sign change on $[1,10]$, so by the Intermediate Value Theorem there must be some $x$ in that range which satisfies the equation.
Answer: I have found one approach
 If If $\log a$, $\log b$ and $\log c$
  are in AP then $a$, $b$ and $c$ are in GP.
Hence, $x^{2}=10^{x}\times \log_{10}x$.
Among the given options this is only possible if x is less than 10 and greater than 1.
Answer: If $x$ is less than $1$, then $\log x$ is negative, and $\log \log x$ is undefined. So (a) is out. Let's look at (b). If $1 < x < 10$, then $0<\log x<1$, and $\log\log x < 0$. Maybe.
Now (c) and (d).  If $10<x < 1000$, then $1<\log x <3$, and $0<\log\log x<\log 3 < 0.5$. We see that the distance between $\log x$ and $\log\log x$ is smaller than the distance between $x$ and $\log x$.
So (b) must be the answer.

We can show that there exists an $x$ in that range that makes $x$, $\log x$, $\log \log x$ an arithmetic progression. As $x$ moves from $1$ to $10$,

the difference between $x$ and $\log x$ moves continuously from $1-0$ to $10 - 1$, that is, from $1$ to $9$.
the difference between $\log x$ and $\log \log x$ moves continuously from infinity to $1-0 = 1$.

Therefore we must have $x - \log x = \log x - \log \log x$ for some $x$ in the interval $(1,10)$.
Answer: I know this is tagged "precalculus", but the following comes to mind ...
Note that if $f(x)=\log_{10}x \text{ then } f'(x)=\cfrac 1 {x \log_e {10}}$
Apply the Mean Value Theorem to $f(x)=\log_{10}x$ at the points $x$ and $y$ with $x>y$ to identify a $z$ with $y < z < x$ such that $\log_{10}x-\log_{10}y = \cfrac 1 {z \log_e {10}}(x-y)$.
Now set $y=\log_{10}x$ and use the arithmetic progression to see that the differences are equal so that $\cfrac 1 {z \log_e {10}}=1 \text { and } z=\cfrac 1 {\log_e {10}} \approx 0.4$.
So we have $y<z$ so $10^y (=x) < 10^z (= e$). And it is easy to see that $x>1$ (for $\log \log x$ to exist).
So to conclude, we have $1 < x < e$.


Adobe Air Debugger lagging my League of Legends

Question: I have two LoL icons on my task bar one is titled Adobe Air Debugger and the other is my LoL client.  I am having random bouts of lag that have nothing to do with my connection of FPS.  I did just install a new graphics card with the most recent display adapter.  Has anyone experienced this before and know how to fix it?
Answer: I would update Adobe air at WWW.Adobe.com and run a graphic card driver update search on the website of the kind of card you got its much more precise.
Answer: Adobe Air Debugger is the program that League of Legends runs through, it IS League of Legends. The lag is server side on the game more often than not.


How do I restore a jailbroken iPhone 3G?

Question: How do I restore to the normal non jailbroken state my jailbroken iphone 3G? Is there any permanent change when you jailbreak it?
Answer: All you need to do is plug your iPhone into iTunes, click on it under Devices:

And click "Restore":

iTunes will make sure that you do actually want to restore:

Jailbreaking does not make any permanent changes; a restore will put your iPhone back exactly the way it was before you jailbroke it.
Answer: There aren't any permanent changes made to your iPhone when JailBreaking. All you need to do is plug it into your computer, open up iTunes, and update/restore iOS normally. This will return it to a fully working, non-jailbroken state.


What is the difference between backing up and syncing an iPad/iPod/iPhone?

Question: What is the difference between synchronizing an iPad/iPod/iPhone compared to backing it up? Is it not the same thing?
Answer: A backup it part of a sync.  Synchronizing your iPhone:

Saves a backup of the installed apps and all personal data (contacts, saved games, documents, etc.)
Adds or removes music, podcasts, etc.
Copies the latest version of apps to or from your iPhone.
(I don't remember the rest of the steps off the top of my head...)

The backup is useful if your iPhone has to be reset to factory settings or is lost.  You can restore your backup to your fresh iPhone and it will reinstall the apps along with all of their data.  Without a backup, you would have to manually type in all of contacts, reproduce your documents, and start your games from scratch.  You'll still have to restore your music manually, but that's a minor issue.
Answer: To expand on Hand-E-Food's answer.
A backup is a complete snapshot off your device at that particular point in the time the backup is made. Not every synchronize causes a backup, and the backup does not contain actual copies of the Apps, Music, Books or Photos stored on your phone. It does however contain all the settings, contacts, calendars, saved games and anything else not handled by the synchronize.
A synchronise copies all Apps, Music, Books and Photos to the phone, and works in conjunction with the backup. When you restore a backup, it will require you to synchronize to retrieve the actual Apps etc.
You can synchronize your phone irrelevant of the backup state, and if you don't restore a back after a reset, you can continue synchronizing items the way you did before the reset, however all your application settings, saved games etc. will be lost and has to be reconfigured and restarted.


How does SharePoint Search handle pending (unapproved) items?

Question: How does SharePoint Search handle the indexing of pending (unapproved) items/documents? As far as I can see there are no pending documents in the index. These seems a little odd to me, since it would be nice, if I could search for all pending items in a site or sitecol. Is it possible to change the behavior of indexing pending items?
Answer: SharePoint Search does by default not index unapproved items as well as draft versions (minor versions). This is so because the search crawling account only has read access to the content and only users with contribute access or better can see unapproved documents and draft versions. Consequently, you could get around the issue by granting contribute access to the search crawling account. But I would not recommend it as your search results will then show documents that are not accessible to users with read-only access.
Comment: Okay thank you. But it is still not quiet clear to me: 1. when I upload a bunch of docs they show that they are pending but also are shown as major versions. 2. Also when I edit an approved  document and save it, it goes back to the pending state. But then it doesn't appears in the search results. It is still strange to me
Comment: Try and enable minor versioning for your document library. Then you can have a last published version that stays in the index while you work on the next major version. Without minor versioning and with content approval enabled the document is removed from the index until you approve the new major version.
Answer: Sharepoint by default only crawls major version of content, because the content acces account only has read permissions one the sharepoint site.
For more details on search and security trimming...
http://support.microsoft.com/kb/2304855
http://www.sharepointblues.com/2010/03/17/draft-item-security-search-results-security-trimming/
Hope it helps.


Why is my station not collecting any resources?

Question: I've got a station within range of a primary industry, but it's not collecting any resources. It's competing with another transport company but they're only transporting 60% of the product.
Answer: There are a number of reason why the industry may not be supplying any goods to your station, but the most likely reason is that the station in question have low ratings for that particular good.
Stations ratings are based on, generally speaking, how often vehicles pick up goods from the station and how much goods have accumulated there. The OpenTTD Wiki provides the complete table: http://wiki.openttd.org/Game_mechanics#Station_rating. You can see the station's ratings by clicking on the 'ratings' button in the station interface.

If your station has a lower rating compared to your competitor, your stations will receive less goods from the industry, and if it has extremely low ratings (after a vehicle crash, for instance) then the industry may stop supplying goods to that station entirely.
Also note that it is impossible to get 100% transported rate as industries do keep a certain amount of the output to themselves. (Source)
Answer: Goods won't start being delivered to a station until you send a vehicle capable of picking them up. If you're waiting for goods to appear before sending your first vehicle, it won't work.
If there are two competing stations and both of them have higher ratings than yours, new goods will only appear at those stations. Send lots of empty pickup vehicles to raise your rating.
Comment: From what I remember there was a setting to change this but I cannot find this anymore?


What criteria are used for classifying composers?

Question: What criteria are used for classifying composers?
Answer: Primarily the time period in which they composed but a composer can span periods and the boundaries can be blurred anyway.
It's easy to say JS Bach is baroque and Mozart is classical, but what about Bach's sons? Is Beethoven entirely classical or early romantic?
Other criteria that could be used would be what forms they composed in and what harmonic vocabulary they used. Even instrumentation and orchestration can be used as a criterion.
Some of Mozart's chromaticism seems before its time in the classical era. Much of Beethoven's later work clearly belongs in the romantic era. You could argue Wagner kicked off a new era just with a single chord progression. Stravinsky's works span three distinct styles.
Answer: (its been a long time since I looked at any of this! Sorry if its not clear)
The most useful criteria are, unfortunately, circular.
- Years active
- Contemporaries
For example, Bach is clearly baroque. I've heard it said that his birth and death dates define the Baroque period.
Sometimes it is difficult to classify a composer as a whole, and the style of the piece needs to be taken into account. Beethoven for example starts in the Classical period, and ends in the Romantic.
Answer: A composer, throughout his or her life, will compose whatever music suits him or her. At some time later in history, a musicologist or historian will stereotype a composer as belonging to a certain style or school of music. The one constant is that composers, while alive, resist and resent being "pigeon-holed" or labeled as being a certain "kind" of composer.
When I was in music school in the 1980s, I listened to music by living composers who were popularly referred to as being of the "minimalist" style. The first thing I found out is that all of the composers in question hated being called minimalist composers. You could say that the definition of a minimalist composer in the 1980s was somebody who hated being called one.
Answer: From my own listening experience (I'm referring to classical music in the European tradition here) I find that geography is also very important. You'll perhaps be able to guess whether a piece is from say the French or German tradition, or from Russia or Italy, even if composers were active during the same broad period, just by listening to it.
BTW, one nice thing about listening to radio stations (and podcasts) on the internet is that you can suite your own taste, because these geographic differences still give partly different flavors to the different national radio stations (think of Europe), so you can learn and choose accordingly.


What's the origin of the stock phrase "tall, dark, and handsome"?

Question: Most everyone has probably heard the phrase "tall, dark, and handsome" being used to describe the physical qualities of a perfect male romantic match.  Where did this phrase come from, and who, if anyone, made it popular?
Comment: would it sound discriminating calling a man from African origin "talk, dark and handsome?"
Answer: The earliest use of it in print that I can find is from The New Monthly Magazine and Literary Journal, 1833. It is from a "paper" titled "The Story of Hester Malpas," by L.E.L.:

Hester now looked at her aunt, who was the very reverse of what she had imagined : she had always thought she would be like her father, and fancied a tall, dark, and handsome face.

According to an excellent post found at Wordwizard.com, and as seen in the citation above, the phrase was originally used to describe women as well as men up until the early 20th century (see EL&U discussion here). Also of note,  the popularity of the phrase spiked after a movie by the same name was made in 1941 starring Caesar Romero.
Answer: I can antedate Callithumpian's 1833, at least by dropping the and. The earliest is in 1815's Scenes on the shores of the Atlantic, Volume 2 By M. F. Dickson:

This Ngram suggests the shorter version is more common:

Before these years, the adjectives tall, dark can be easily found together in many places, such as describing men, mountains and trees.
Answer: I've just heard an anecdotal report on "Travel with Rick Steeves" radio show (American Public Radio) that the Scots believed that to have a stranger who was tall, dark and handsome appear on New Year's as the "first footer" meant good luck all year - as Viking conquerors would have have been blonde, and there to collect taxes or worse. No real etymology research here, but makes a fun thought, and would likely predate much of the written practice.
Answer: This is a phrase associated with the upper class Europeans along with another allied phrase, namely, "prince charming". Trace it back to Europe especially around the time that the "swarthy" Moors were the masters of Spain. The Shakespearean play Othello is a definite clue. The search will also no doubt find that during the same period the European upper class prided themselves in being extremely pale and free of the tell-tale signs of having had to spend any appreciable time in the Sun. Hence the term "blue blood" that came about as the extremely Sun deprived skin would exposed the veins in a bluish hue thereby giving the illusion of one having blue blood.
Answer: Probably Europe.
Other cultures outside of Europe (with darker skin) seem to think that lighter skin is more beautiful.
Comment: I'm pretty sure it's dark hair, not dark skin, which is meant.
Answer: Not to directly answer the question about the phrase, but I'll point out that biologically, men and women are believed to be hard wired to seek certain physical traits in partners that ensure that they will hook up with a good mate. For women, a tall male is more likely to be big and strong and able to defend her and provide for her. Within any stable ethnic group, men are more likely to be slightly darker in skin color, as they do not have to produce as much Vitamin D (via sunlight on the skin) as women do (for bone growth in fetuses and nursing babies). And "handsome" can mean a number of physical attributes, from facial symmetry (indicating good genes) to sharp features (indicating high testosterone levels and thus likely fertile, as well as an aggressive defender). All three together suggest that a man would make a good mate, and the female should be receptive to his advances.
Men, of course, have physical attributes they look for in females, indicating potential good mates, and call this "beauty". Note that all this assumes heterosexual orientation -- I can't tell you what gays or lesbians seek in a partner.
Now, before anyone blows a gasket, downvotes, or edits this, I understand that you might well consider this to be more along the lines of pop psychology than proven science, and that's your right. It's quite plausible, but certainly not proven. And of course, a society, its cultural norms, fashion, personal tastes, and even who is making advances towards whom, can override whatever hard wired attributes are considered desirable in a potential mate's physical appearance. I'm just saying that "tall, dark, and handsome" may well reflect a deep, even hard wired, female viewpoint on what appearances make for a desirable male, and the language reflects that, rather than being an artificial literary construct.
Comment: Not an answer. Not science.
Answer: Suits and Tuxedos may be the source of the "dark, and handsome" part. Wearing nice clothing can also make people "stand taller," because they are proud of their clothing.
Comment: This answer is probably just speculation, but I'm giving it credit for at least attempting to answer the implied (and in my mind, more interesting) question of *why* or *how* this phrase came about.  A list of publications and dates may answer the question asked more literally, but is dry and not very explanatory.


Refrigerator drips water inside

Question: My mom's refrigerator drips water inside.  Is it because she is opening it too often, holding the door open, or is there another possible reason?  At times it's so bad there are pools of water.  She lives in Missouri where it has been extremely hot and  humid.
Answer: Warm moist air goes into the fridge and condenses. This is where you get the moisture. Normally, there's a drain, perhaps below the veggie drawers, that ducts the excess moisture away to a tray below the evaporator coils.
It's common to have this drain clog. You can try pouring in boiling water to clear it, but you may overflow the bottom tray and need a mop.
You can also try soft copper wire, like 14 gauge stripped electrical wire, which should not poke any holes in anything yet still be stiff enough to clear the jam.
Answer: Most refrigerators manufactured today receive their actual "coolness" from the attached freezer.  The attached freezer sections must have periodic defrosts, otherwise the air pathways which circulate the cooled air will become blocked.
In the good old days, the consumer freezers were defrosted manually when they became so full of frost that nothing much would fit.  The newer ones all have auto defrost at varying periods from daily to thrice daily.
The vapor pressure of water in the presence of a freezer is very high - an open freezer or refrigerator will literally suck the moisture out of the air (this is why your lips crack while you are skiing and why the glass cooler doors at the store are difficult to open immediately after you close it) and condense it to water or ice.
Anyway, the defrost cycle produces lots of melted water, which must drain somewhere; which is usually underneath your appliance or the floor.  There is usually a tube to drain the freezer water from defrost to the drain pan.  What usually happens is that mold grows in the drain tube.  Someone else mentioned above to use a soft wire to clean the tube, this is correct procedure to clear the blockage.
To cure it for a long period (roughly equivalent to the elapsed time between the purchase of the refrigerator and now) run bleach down the tube to kill the mold (yes it's probably mold) growing in the tube.  What I usually do (or have done) is pinch off the low end of the tube and fill it with household bleach and leave it for a bit (5 minutes is fine).  Then open it and allow it to drain and rinse well with water.  Clumps should come out, uck!
Oh yeah, don't forget to empty the container you use catch all the junk that comes out of the tube.
Hope this helps.

Refrigerator drips water inside


Relation between the wave front set and the semiclassical frequency set

Question: I need to prove that the wave front set of a distribution (as defined in Hormander's "The analysis of linear partial differential operators I") is equal to the semiclassical frequency set of an h-dependant $L^2$ function minus $R^n\times 0$, and conversely the semiclassical frequency set is the wave front set plus the points of $supp(u)\times 0$, but I don't know how. Some help (or bibliography) on this matter'll be highly appreciated.
Answer: Let $u$ be a distribution on some open subset $\Omega$ of $\mathbb R^n$. A point $(x_0,\xi_0)\in
\Omega\times\mathbb S^{n-1}$ does not belong to $WF u$ when there exists a neighborhhod $V$
of $x_0$ and a neighborhood $\Gamma$
of $\xi_0$ (in the sphere $\mathbb S^{n-1}$)
such that for all $\chi\in C_c^\infty(V)$ and for all $N\ge 0$,
$$
\sup_{\lambda \ge 1,\ \xi\in \Gamma}\lambda^N\vert\widehat{(\chi u)}(\lambda \xi)\vert<+\infty.
$$
This is equivalent to:
there exists a neighborhood $V$
$\dots$ for all $N\ge 0$,
$$
\sum_{\nu\in \mathbb N}2^{2\nu N}\int_{2^\nu\le \vert \xi\vert\le 2^{\nu+1}, \frac{\xi}{\vert\xi\vert}\in \Gamma}\vert\widehat{(\chi u)}(\xi)\vert^2 d\xi<+\infty.
$$
This is equivalent to:
there exists a neighborhood $V$
$\dots$ for all $N\ge 0$,
$$
\Vert(\mathbf 1_\Gamma)(D/\vert D\vert)\phi(h D)(\chi u)\Vert_{L^2}=O(h^N),\quad\text{$h\rightarrow 0_+$},
$$
where
and $\phi\in C_c^\infty(\mathbb R^n)$ supported in a ring
{$\eta, 1/2\le \vert\eta\vert\le 2$}.


What white fish can be used in rolled sushi?

Question: I have been making sushi using salmon and tuna for a while, but i would like to know it there are any firm white fleshed fish that will work well in a rolled sushi paired with apple and cucumber. I tried cod but it doesn't carry a lot of flavor. I had also thought about tilapia but had never seen it served in a sushi restuarant and wasn't sure it would be suitable.
Answer: White fish are, as a rule, more delicately flavored than darker fleshed fish. Add farm-raised to that equation and you have the makings for a very bland meal, which is why you almost always see farm-raised white-fleshed fish served with heavy herb treatments and powerful sauces, or (in cod's case) fry batter. Tilapia and cod are two of the most common farm-raised fish on the market, so I'm leaning heavily on my suspicion that you're trying to make sushi out of the farm-raised varieties and not wild game.
If it's white fish you desire for sushi, talk to your fishmonger. Tell him what you're doing and ask for his recommendation. He'll direct you toward game fish that that are either very new and very fresh or that of the flash-frozen variety.
Answer: Fluke in season works well
Comment: does fluke have another name? I'm on the gulf coast so it can be kind of hard to get northern fishies here.
Answer: A common one is haddock and is in season pretty much year round.
Answer: This is cheating, but white tuna is delicious.
Ditto the blandness.
Answer: On the contrary, tilapia is almost always served raw at sushi bars.  It is usually what you are served when you order red snapper.  No joke.  It is pretty tasty if you get it fresh enough.
My personal recommendation for a lighter-flesh fish would have to be yellowtail (hamachi).


Dialogue Recording Levels

Question: Got into a discussion with a teacher today about the proper level for recording audio, specifically dialogue.
She was telling us that keeping it between -6 and -12 is what she does but who the hell speaks with that kind of dynamic range? I was under the impression that it was -12 to -24.
Recording at the Dialnorm seems like it could decrease some noisefloor. Anybody have some recording level norms? I've googled it and come across a few answers but I want to see what this forum has to say!
Answer: The numbers you give seem to me to be when (post-prod) mixing. That's where I aim voice levels to be in a soundtrack. Talking purely about recording: I record dialogue as high as possible, obviously with safety. I aim to get the best wanted signal (voice) to noise (background) ratio. So the loudest moments will be just below 0. Depending on performance, voice can have a big dynamic range.
If recording too low, you won't be getting rid of noise, as you'll have to bring it up later in post. Not only will you be bringing up the background, but also any noise from the system. Rather record hotter, and bring it down later than the other way. It's kinda of a fine line though, cause you really don't want to be gaining up your recorder/mixer to the max either, as that will add way to much noise.
I'm just talking from my personal experience here, there are veterans hanging around here with tons of experience. Im curious as to what they say.
Answer: When we are dubbing for cartoons, we usually record around 0 dB on the meter, which is -10dB in Pro tools. Offcourse whispering will be softer and you dont gain that up to the max.
Answer: There are several factors involved; as with any type of recording there is 'no size fits all'. It depends on the subject being discussed, type of person and their animation whilst being interviewed, background noise etc. It's a matter of balancing maximum gain (digital amps are less noisier at max gain) without clipping, and whether you've opted to include the safety net of a limiter. If it's a one shot, with no chance of a pre-test then I suggest recording in the -12dB region and switch on the limiter, as once clipped the recording is ruined and opportunity lost.
I cannot stress the importance of using max gain where possible for digital amps; they perform best at that point. It is often better using a pad and hi-pass filter to reduce the signal input in order that max gain can be used on the recorder.
Answer: +1 on Andrew's answer. When recording, the objective should be to get as clean, clear and present a recording as possible. A good boom op will be able to position the mic as close as possible to the talent (without being in the shot) in order to achieve this. It's in post where the dialogue levels will be adjusted to fit the desired norms. By aiming to record at a certain level you risk recording too low and, as Andrew says, the noise floor will be more present when mixing.
Inversely, you should always avoid recording clipped dialogue so don't record too hot!
Answer: Peronally I dont think you should see it as a wake up call!
On location its WAY more important to capture the dialog without clipping than anything that has anything to do with technical noise floor.
Getting as close as possible is a given and minimizing real world noise is as well. but dont record hot as it WILL get you (and us in post) into trouble.
If you aim to peak normal dialog at -6dbfs you WILL clip a bunch of material. Digital clipping sounds awful and is hard to remove cleanly even with izotope.
Using all the bits and worrying about system noise in location dialog recording is NOT time well spent, good gear today have enough headroom. Spend the time on removing actual issues in the room (such as reverb, sole noises, fans etc) instead of trying to maximise recorded levels. The dialog editors will love you. They will hate you for clipping the dialog...
Answer: Once, keeping general level between -12 and -6 was a necessity. We had only 16 bits (65535 individual steps with a possible range of 98dB), which meant the noise-floor was just around the corner. It was doable though mostly because limiting on the inserts, and as the gains where greater this way than the losses, we went with it. Actually, dialogue at that times where anything but sweet anyway, so noone noticed.
Now, we have 24 bit and beyond, 16777215 individual steps with a possible dynamic range of 144dB, with a dynamic range raised 6dB with each new bit. That means, to reach the same results as as a DAT on a modern fieldrecorder you can theoretically lower the gain approx 46dB. It's really not a good idea to do so as it would assume the recording quality (not to be confused with final quality) to be good. And it's not. We use the extra headroom and fidelity to make the movies sound better than they ever has and progress as an artform. I know many try to compare resolutions based on numbers, and that works more or less well for analogue formats (for example, cinema sound hasn't gotten louder with improved magnetic capabilities, they adopted a higher headroom instead), but in digital media the higher resolution makes a big difference, giving a more transparent, living and vivid result.
With that said, we now have the option to record even very dynamic sources with both full, undistorted, and relatively noise-free material by just adjusting to the new specs of modern day apparatus. Which sadly is something I've realized many old teachers find pretty difficult...
Absolutely everything that affects the material degrades it. In a studio that's okay as you have control over it and can make more thought-through choices to reach transparent results if you can't undo them altogether, but on location, absolutely everything, be it an ugly brick-wall limiting, raising background noise/ugly mouth-sounds, or perhaps killing important transients altogether, will stay and can never be fixed to what it was supposed to be, alternatively take a tremendous amount of time could it be fixed at all. Besides that, on location there are no time to think things over too much, you must find a quick way to work and keep it on the safe side to avoid unexpected problems as far as possible. As very few people understands what we're doing, more responsibility to reach acceptable results lands on us, and that includes using our equipment as effectively as possible.
I follow pretty simple rules when I record dialogue nowadays; Keep centered level around -20dB, try to keep peaks below -3dB, preferably below -6 if possible, and keep any on-location processing, like filter and limiting, to an absolute minimum, if any. If I'm unsure how things will progress, I rather keep levels lower than higher to be on the safe side. I do of course always keep the limiter on anyway, as a slightly flattened peak still sounds pretty good even in editing if any peaks would cross 0, and they will at some time or another most definitely do, whereas a pure clipping sounds crap and might very well seriously F up a very important take, and make mixing less good. Something few directors are very forgiving about if there aren't a very good environmental or logistic reason...
Answer: Thanks for the input, fellas, I'll be sure to keep all this in mind.  I've been recording from -24 to -12 and I've had great results so far.  I think think this has been a wakeup call!
Answer: In my experience after dubbing a lot of cartoons and stuff for tv that since tv in india is at -10 dB (sd cable or satellite), while dubbing in studio I set my preamp to get levels of max -10dB in protools for normal dialogues and upto -3 for any angry/shouting dialogue, cause everything is gonna be compressed/gain lowered later to fit with in -10 on tape
But for some major theatre release films, that I have started dubbing (with 2 mics) on with a reputed sound designer, all levels are hot, in the sense that I or the sound designer set the gain on the preamp to get levels as high as possible with out clipping.
In both cases-tv/films, for a loud shouting kind of dialogue, the artist is asked to step back a little, to get more voice projection without clipping. If he movies back too much he starts sounding hollow or I hear room tone.
Answer: -18vu (-21 rms) full scale (0 dB peak). adjust dynamics with compression accordingly. i'd recommend 1.8:1 tight attack and release with just enough threshold to get it into the proper level spec.
Answer: In the studio recording voices for animation I'm aiming for around -10 or a bit lower. One important factor is knowing the actor and the script. If the script calls for sudden yelling or it's a very emotional moment, I am a bit lower. The same if I'm not familiar with an actor, or if I know it's an actor who's really all over the place. But when Seth MacFarlane steps in the booth, for example, knowing the characters and the script makes the levels very predictable, and I can safely aim for about -6 to -8 and get a particularly clean, hot recording.
I also aggressively ride the gain or fader as appropriate—in animation especially there is no set-it-and-forget-it.

Dialogue Recording Levels


What specific actions decrease a weapon's condition?

Question: I know that "using" a weapon will cause its condition to decrease.  What specific actions will cause the condition to drop?  Is it only if a weapon connects with an enemy and causes damage?What if a weapon is used to break an object (boxes, vases, etc.)?Does simply swinging or shooting a weapon cause a decrease in condition over time even if it doesn't connect with anything?Are the specific actions that decrease a weapon's condition universal or are there different conditions for different weapon types (daggers, fae blades, longbows, sceptres, etc.)?If there are different actions that can decrease a weapon's condition, does one decrease the condition more than another (if striking an object and striking an enemy both decrease a weapon's condition, does striking an enemy decrease the condition more quickly)?
Answer: The amount of degradation your weapon experiences is directly proportional to the amount of damage that your weapon inflicts.
Since your weapon will only inflict up to the remaining health of the entity you are attempting to destroy it will only degrade by that amount. In other words, if you have a set of Prismere Chakrams that inflict 199 damage and you attack a poor defenseless storage crate that has, let's say, 5 armor, your weapon will degrade by whatever 5 attack does to it and not 199.
I had a similar question when I was questing near Didenhil: Does attacking boxes hurt my weapon? So what I did was fairly simple: I repaired all my stuff at the blacksmith, ran outside and smashed a bunch of crates, then ran inside and repaired my stuff again. Lo and behold, they had a bit of damage (-1). Then I thought, what about my staff? What if I just launch a bunch of fireballs and don't actually fight anything? And the answer is yes, that does degrade your weapon. I would assume that if you are dumb enough to use a sceptre, it would also degrade in a similar fashion. Physical/piercing weapons do not seem to be affected by just waving them about.
Answer: As far as I know your weapon decreases whenever it hits something, if you are just swinging in the air it does not decrease. But hitting boxes, enemies, or even walls it will slowly start to decrease everytime it makes contact with something.
Also it is the same across all weapon types, the staff and sceptre are the same, each blast out of that hits something  will make it decrease slightly.
It is possible that hitting a box might degrade the weapon a smaller amount than hitting an enemy, but I have not seen any evidence playing the game or from other people through the community if there is a difference.


get facebook status

Question: I'm looking for a good, simple PHP or JS function to get my latest Facebook status updates. Anyone have a good solution?
I had a JS script but simply stop working.
heres the code:
view code
Thanks in advance!
Comment: ad link) 404...
Comment: Fixed the link, it had an extra / ... but I don't see what this has to do with WordPress.  You're just using JS code ... vote to close and migrate to Stack Overflow ...
Comment: Where is your WordPress question?
Answer: There is no real "easy" way to do it anymore, due to Facebook's requirements for an application and an access token and OAuth and so on.
The latest version of my Simple Facebook Connect plugin has a working User Status Widget in the widgets module. It can display the latest status for a user in the sidebar or in any widgets area of the theme.
Setting it up requires creating a Facebook Application for your site. This is not a minor task, but it's fairly straightforward.

get facebook status


Why can't I mine ore veins again even though it looks like they've respawned?

Question: After mining out all the ore in several mines, I returned (after a month which should be plenty of time for the ore to re-spawn) only to find that I still can not mine the ore. I can tell that it has re-spawned because I can see that the coloration has returned, but I am not able to interact with the ore in any way. Why can't I mine the ore any more?
Answer: The coloration returning does not always indicate that it has fully replenished.  It will return in due time.  If you have already waited a month, it shouldn't be too much longer.
Comment: actually, if going into a cell resets the spawn timer then it will be a **whole lot longer** :D
Comment: I also mined the ore, saved, turned off my console, reloaded, and it replenished.
Answer: If an ore vein looks like it has ore to mine, but you cannot interact with it, you can leave the area and immediately re-enter it again, the veins will become minable.
Answer: I had the exact issue on my PS3, I just quit the game and went back on and I can mine it all now :) try quiting and re-opening the game, or restarting your console.
Answer: When I had this problem on xbox, I would just leave the mine or cave and then go right back in.
Answer: If you are using pc, go into thirdperson, enter console by pressing ~ (under escape) click on your character and type TAI.
Then type TAI again to enbale ai again. Then exit console and it should work.
Answer: You have a collision problem. I think the respawn is actually a week, but if you're on PC, just open console, select the ore vein, hit disable, then enable, and you should be able to mine. It's a glitch. Nothing you can do if you're on console, you'll just have to wait for a patch.
The colouration returned + can't use = Glitch. Try walking into it, you'll clip right through.
Answer: I had this problem too, I found that if you just attack the ore with your pick, you can mine it.


What products are available to make coved ceilings?

Question: Due to massive cracks and drooping ceilings we need to tear off our existing plaster/lath walls and replace with sheetrock.  The 1948 house currently has coved ceilings that we want to duplicate when we do the remodel.  Are there products available to help create the coved look that would make the job easier for a novice?
Comment: when you say coved ceilings, do you mean coved crown moldings or a complete arched radius to the wall?
Comment: A complete arched radius to the wall.
Answer: Although I have never used them, and don't know the brand names, there are light weight cove sections made from composites that you can nail or screw to the wall/ceiling, then finish in with mud. I'm quite sure I saw a tutorial on using these products on the TOH website. If I can find it, I'll post the link.
Comment: Here is one example of kits. www.archwaysandceilings.com
Answer: Your coving was most likely created using a mold of some kind, you can still buy molds and do the work, but it is not easy or quick. I've tackled lots of jobs but I'd never try that one myself.
In the states and the UK (I've lived in both) you can get preformed plaster and styrofoam coving in a variety of styles, and that's much easier to work with. Styrofoam is very inexpensive, and easy to work with as it is extremely light. If you make a bad cut you just use another piece, and just glue it into place and then prime/paint. Preformed plaster is heavier and harder to cut and fit, however it is stronger and may last longer.
Personally I'd go for stryofoam, it may not be as sturdy but it's so much easier to work with! Just be very careful not to damage it as you work with it.
Answer: You don't say where you are based (I'm assuming the USA), but in the UK you can buy preformed plaster coving in a variety of styles:

Sculpted
Egg and Dart

These are from Screwfix, but other places sell them as well.
These can be cut with a mitre saw to form corners, or some types have pre-cut corner packs you can buy. With an older house it might be best to cut the corners yourself as you can account for the variations that will occur that make the corners not quite square.


Private domain purchase with paypal: how to prevent fraud?

Question: I am finally going to buy a domain I have been looking at. The domain owner wants me to give him my Godaddy account information and send him the payment via Paypal gift, so that there will be no extra charges. Should this cause suspicion? Does Paypal offer any kind of fraud protection? What is the best way to protect myself from fraud in this situation, without the need for escrow services, such as escrow.com? Any advice welcomed. Thanks.
Answer: If you are purchasing a domain you shouldn't be giving them your godaddy.com account information. That is completely unnecessary. And when buying a domain always use an escrow service. That way you can be sure everything goes smoothly and you don't become a victim of fraud. Sending the money via PayPal is almost as good as giving them cash.
Basically, if you do what they say, you are setting yourself up to be defrauded. Don't give them any login information for anything and use an escrow service. Otherwise bail out on the transaction. If they are legitimate they will agree to this.
Answer: Smells funny to me. I wouldn't give up my account information to anyone. I have gotten a 90% refund from Paypal when I was suckered by a bad eBay auction (the auction price less a few fees), so they do have some fraud protection in place.
Why don't you contact GoDaddy and ask how they would recommend a safe transfer? I've had very good interactions with their customer service. Tell them straight up you're worried about fraud, and ask how you can protect yourself.


When I wake up before Alot Hshachar and won't go back to sleep, what can/can't I do?

Question: If I wake up early in the morning, like any time from 2am to 6am, before Alot Hashachar, and I'm pretty sure I'll start my day and not go back to sleep, at least not before a possible afternoon nap, what can I do in terms of hand washing, birchat hashachar, birchat haTorah, learning Torah, drinking something, doing exercise, and eating a snack or a meal?  I'm never sure what to do, and I end up neither eating, drinking, nor learning Torah until after the time to say brachot, or even until after netz.  I'd prefer to use these quiet, early hours to learn Torah or work on my religious studies and religious research than to read secular material or watch videos or clean the house, if I can, so I'd really like to know what is permissible.  Thank you so much for this site and for your help.
Comment: related/dupe(s)? http://judaism.stackexchange.com/q/7364/759 http://judaism.stackexchange.com/q/10188/759 http://judaism.stackexchange.com/q/1173/759
Answer: Birkot HaShachar can, according to the Magen Avraham (47:13), can be said as early as midnight, but I'm not sure if that's the general custom, because I've noticed that people usually wait until alot hashachar.
In general, the Shulchan Aruch (89:3) says that you can't perform anything for yourself, but doing things for the purposes of a mitzvah is ok. Based on this, the Mishnah Berurah allows buying food for Shabbos if the markets are only open in the morning (there, seif katan 36) and R' Shlomo Zalman Auerbach (quoted in Tefilah Kehilchasa 6:36) allows doing anything for one's wife and family, as these are acts of chesed.
Eating: The Mishna Berura (S"A 89:5, Mishna Berura 27) says that you shouldn't eat a meal beginning from half an hour before alot hashachar. Before that time, though, it is not recommended by kabbalah but otherwise assumed to be allowed (Aruch Hashulchan 89:26).
Drinking: according to the Aruch Hashulchan (89:23) drinking coffee or tea with milk and sugar, if that's the normal way of drinking it, is allowed before davening (even after Alot Hashachar).
Learning: as above, Birkas HaTorah can be said before dawn (47:13), and if one fell asleep during the day, even before midnight (Mishna Berura there, seif katan 28)
Exercising: In "Halakhically Speaking" volume 1, the author quotes Rabbi Belsky as saying that if one's intent by exercising is to be stronger for 'avodas Hashem', it can be done before davening.
Answer: you need to do the Birkot HaShachar first, and do Torah Study, after this you can eat or drink. (According to Shulchan Aruch)
The Birkot HaTorah is only recited in morning (change of sky from black to blue), or you can see in myzmanim.com, search for DAWN, this is the best time to start.
Comment: Actually, according to Shulchan Aruch OC 47:13 The Birkot HaTorah is recited even before dawn after waking up. -1
Comment: Is there any time I would have to stop learning, eating, or drinking, for example, the time a fast would begin, or could I continue doing everything until I'm ready to daven at the regular time?  Thank you.


Groups - order of elements (element of order 3)

Question: I need to prove there is no group that contain only one element of order 3.
im don't know where to start because I don't really know anything about the group.
will appreciate your help
Answer: Hint: Suppose $a\in G$ has order $3$. What is the order of $a^2$?
EDIT: Since $a$ has order $3$, we know that $a^3=e$, the identity element. This means we can calculate $$a^2=a^2,\quad a^2\cdot a^2=a^4=a^3\cdot a=e\cdot a=a,\quad a^6=(a^3)^2=e^2=e.$$ Hence, the order of $a^2$ is $3$.
The only problem might be if $a^2=a$, but if that is the case, then we can multiply both sides by $a^{-1}$ and see that $a=e$, which is a contradiction since the order of $a$ is $3$, not $1$.
Comment: how can I know what is the order $a^2$?
Comment: @Mary: I've edited my answer so hopefully it is more clear, now.
Answer: Assume there exists exactly one and (one and only one ) element $a\in G$ of order $3$. Then the order of $|G| \ge 3$, and more importantly, there exists a subgroup $H = \langle a \rangle \leq G$ such that the order of $H$ = $|H| = |\langle a\rangle| = 3$. i.e., $a^3 = e$, the identity element of $G$. So $\langle a \rangle = \{e = a^3, a, a^2\}$.
Claim: if $a$ generates $H$, and the order of $a$ = |H| = 3, then $a^2 \neq a$ also generates $H$ and hence, $a^2$ is also of order $3$.
Recall, that the order of any cyclic subgroup (like $H = \langle a \rangle$) which is generated by the element $a$ is the order of the element that generates it. And the order of an element $a$ that generates a group $H$ is equal to the order of the group it generates. So we claim that $|\langle a^2 \rangle| = |H| = 3.$
We can see this more clearly by computing the elements of $\langle a^2\rangle$:
$a^2 \in \langle a\rangle,\;$ $(a^2)^2 = a^4 = a^3\cdot a = ea = a \in \langle a \rangle,\;$ and $(a^2)^3 = a^6 = (a^3)^2 = e^2 = e \in \langle a \rangle$.
Hence, $\langle a \rangle = \langle a^2 \rangle$. But then both $a$ and $a^2$ have order three, knowing that $a \neq a^2$, we have a contradiction, since we assumed $a$ was unique.
Hence there cannot be a unique (there cannot be one and only one) element of order $3$ in any group; if a group has an element of order $3$, it has at least two elements of order $3$.
Comment: Deserves a positive! +1
Answer: Another approach to this: let $G$ be a group and $a \in G$ the only element of (finite) order $n$. Then $n=1$ or $2$. Proof : $ord(a)=ord(a^{-1}$), hence $a=a^{-1}$, that is $a^2=e$, the identity element. We conclude that $a$ is the identity element or $a$ has order 2.


Where is the line on helping with homework?

Question: Here's something I know a lot of parents with school-age children struggle with. What's the line between "helping" a child with their homework versus out-and-out doing it for them? At what point is too much help a problem? How would one know if they're starting to do the assignment for the child rather than providing guidance/assistance?
Answer: As a former math tutor to children in middle and high school, and now a father, I can tell you a way to avoid the problem completely. Gain an understanding of the concept yourself, and make an equivalent problem that uses the same steps/ideas. Walk them through step by step, explaining as you go. One or two examples like that should be enough for them to understand well enough to do other work on their own.
This takes a bit more work, but it really teaches them. Most kids will be all too happy to just copy you or follow your lead and never gain an understanding of the work. The best way to avoid it is to do absolutely none of their actual work.
Comment: +1 - Understanding the modern methods is important.  There are books to help parents get to grips with new math (and other) techniques.  (Welcome to Parenting SE by the way!)
Comment: Succinct, clear, and a great answer. Welcome to Parenting.SE, we hope you join us in the chatroom some time. :D
Answer: There's a pretty clear line between "doing the work" and "helping someone understand how to do the work".
One technique is to ask the child to explain to you how a problem would be tackled; or if the child is baffled to ask the child if the problem can be split into smaller bits, and how one of those smaller bits would be tackled.  That makes them do some work, and explaining something always seems to make things clear for the person doing the explaining.
Sometimes children just don't get something.  I have never been able to do "long division", and it's nice if a parent can recognise that and ask the teacher if there are other techniques.
Finally, having a source of appropriate research websites available would be handy.  Here's a UK website from the British Broadcasting Corporation with a lot of useful information - some media might not work outside the UK.
http://www.bbc.co.uk/schools/
Answer: The way I have looked at it is if I am writing anything down I am doing it, I will coach my son into trying to work out the answer giving him more hints if he is not getting it.  Sometimes it will take a bit with certain subjects, but usually we work it out.  Writing is harder, and we do Chinese characters for his Chinese School, so for that if I must write I will do it on a separate piece of paper so no matter what he will still need to write it on his own.
Comment: +1 for not writing on their paper, that makes a pretty clear line. I used to use a small lap sized white board to work out problems on. Often due to it's small size (relative to the big markers for it) we would erase the first part of it to make room to finish the problems.
Answer: You know you're doing the problem FOR  them when they continue to ask you to 'do the next step(s) for me' - and you do them, repeatedly - the same 'type' of problem.  It becomes obvious that they haven't learned the concept behind the homework.
I worked with my daughter to help her understand how to start working on a problem, most notably word problems for math & science. Basically, I taught her how to get from point A to point B.  I would never just 'do' the problem and give it to her, because that's not HELPING her.
Answer: In my schooldays, math caused me the biggest troubles. My father's help was fantastic, but he never solved any problems for me.
Instead, my father taught me the principles, or helped me understand the ideas, on which the problems were based. He never wrote anything down on paper, but we had a blackboard that he used for graphs and formulas.
For writing assignments, the hardest bit was getting started, and keeping going for long enough at a time. My father would then sit near my desk and repeatedly ordered me to Write! he'd keep doing that until I had something substantial that I could finish on my own.
I'm going to get a whiteboard for my kids. And a comfy chair by their desk.
Comment: When I was tutoring math one of the key things I did was to not use the problems in the book to demonstrate the concepts. Pretty much the same as your dad... show them the concepts, not how to do the problems in the homework.
Answer: What do you see homework as for?  What are you teaching them by helping them with their homework?
If homework is to help them learn, you can teach them about understanding and working through a problem, about team work, and that they can do the homework themselves. (With a little help in the right direction)
What you don't want to teach them is that can avoid work by getting others to do it, that delaying work until they don't have enough time to do it means they won't have to do it, that they can't do it for themselves.