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Comet surface changes before Rosetta's eyes
In the months leading to the perihelion of Comet 67P/Churyumov-Gerasimenko, Rosetta scientists have been witnessing dramatic and rapid surface changes on the Imhotep region, as reported in a paper to be published in Astronomy & Astrophysics
Since arriving at Comet 67P/C-G in August 2014, Rosetta has been witnessing an increase in the activity of the comet, warmed by the ever-closer Sun. A general increase in the outflow of gas and dust has been punctuated by the emergence of jets and dramatic rapid outbursts in the weeks around perihelion, the closest point to the Sun on the comet's orbit, which occurred on 13 August 2015.
But in June 2015, just two months before perihelion, Rosetta scientists started noticing important changes on the surface of the nucleus itself. These very significant alterations have been seen in Imhotep, a region containing smooth terrains covered by fine-grained material as well as large boulders, located on 67P/C-G's large lobe.
"We had been closely monitoring the Imhotep region since August 2014, and as late as May 2015, we had detected no changes down to scales of a tenth of a metre," comments Olivier Groussin, an astronomer at the Laboratoire d'Astrophysique de Marseille, France, OSIRIS Co-Investigator and lead author of the study.
"Then one morning we noticed that something new had happened: the surface of Imhotep had started to change dramatically. The changes kept going on for quite a while."
First evidence for a new, roughly round feature in Imhotep was seen in an image taken with Rosetta's OSIRIS narrow-angle camera on 3 June. Subsequent images later in June showed this feature growing in size, and being joined by a second round feature. By 2 July, they had reached diameters of roughly 220 m and 140 m, respectively, and another new feature began to appear.
By the time of the last image used in this study, taken on 11 July, these three features had merged into one larger region and yet another two features had appeared.
"These spectacular changes are proceeding extremely rapidly, with the rims of the features expanding by a few tens of centimetres per hour. This highlights the complexity of the physical processes involved," adds Olivier.
The sublimation of volatile species is clearly an important factor, as colour images of this region reveal the signature of exposed ice on some of the rims of the newly-formed surface features. The rapid rate of expansion is unexpected, however: models of sunlight-driven sublimation would predict erosion rates of just a few centimetres per hour, and thus the scientists believe that additional mechanisms are required to explain the observations.
A simple possibility is that the surface material is very weak, allowing for more rapid erosion, but it is also possible that the crystallisation of amorphous ice or the destabilisation of so-called 'clathrates' (a lattice of one kind of molecule containing other molecules) could liberate energy and thus drive the expansion of the features at faster speeds.
The erosion could be accompanied by increased rates of gas outflow, including H2O, CO2, or CO. The scientists also searched in OSIRIS images for evidence of increased dust rising from Imhotep as the surface morphology evolved, but did not find any.
While it is unlikely that many small (micron-sized) dust particles were released as the features formed and expanded, it is possible that the same amount of mass was released in a smaller number of larger (millimetre-sized) particles, which would produce less reflected light and thus be harder to detect with OSIRIS.
In addition, a significant fraction of the dust released may have immediately fallen back to the surface, accumulating at the base of the expanding rims.
Although the scientists were initially surprised to see such significant changes taking place on smooth terrains such as those seen in Imhotep, the location of this region close to the comet's equator guarantees that it receives large amounts of sunlight.
"We are looking forward to combining our OSIRIS observations with data from other instruments on Rosetta, to piece together the origin of these curious features," concludes Olivier.
More information: "Temporal morphological changes in the Imhotep region of comet 67P/Churyumov-Gerasimenko," A&A, Received: 21 July 2015 / Accepted: 08 September 2015 DOI: dx.doi.org/10.1051/0004-6361/201527020
Journal information: Astronomy & Astrophysics
Provided by European Space Agency


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Words: Frits Van Oudtshoorn for The Firth Group of Farms
The grazing management strategies followed on livestock or game farms are the main aspect determining long-term sustainability (financial and environmental) of the farming business. Poor grazing management results in a reduction in grazing capacity of the veld, which then necessitates the reduction of animal numbers and/or the provision of supplement feeding at a cost. Continuous poor grazing management may even lead to a permanent reduction in grazing capacity if topsoil and nutrients are lost through erosion.
Good grazing management, on the other hand, increases the carrying capacity of the veld, leading to an increased potential stocking density with animals feeding and producing on the most affordable feed resource, namely good veld. At the end of the day, good grazing management is not an option but a necessity (not only for our own sake but also for future generations).
But what is good grazing management? I believe good grazing management strategies and systems should be based on ecological principles related to historic grazing patterns.
Before the first farms were fenced off from the 1920s onward, large herds of grazers in grassland, savanna and karoo were migrating annually. This nomadic behaviour was mainly driven by female animals and associated with the search for greener pastures. Additionally, migration to known sources of water and to limit predation also played a role. The forward movement of herds was driven by abundant feed in front and the lack of feed and build-up of dung and urine at the back.
In general, migrations took place between sweetveld (winter) and sourveld (summer). In many cases migrations followed circular routes and were almost continuous, spending only a few months in one area when female animals were heavily pregnant and during birth.
The size and density of herds were closely related to rainfall regions and the influence of rain on the availability of fodder. In high rainfall regions, where fodder production and consequently grazer numbers were high, the size and density of herds were also high, and vice versa for low rainfall regions. Herd densities were particularly high in the presence of predators. The denser the herds the higher the level of non-selective grazing, short-term trampling and concentration of dung and urine.
Animals that did not partake in migrations (e.g. old, weak and injured individuals) were heavily preyed upon. The reason for this is that predators are territorial and relied on the relatively few number of animals for prey after large herds moved past their territory. Non-migrating species, such as kudu and impala, were also heavily preyed upon.
These historic grazing patterns took place for millennia and the veld ecology is well adapted to it. Understanding and incorporating these principles into our grazing strategies would therefore be vital for sustainable veld management.
What are the main ecological principles we can derive from the historic grazing patterns? Below, I list some principles that stand out;
Veldrest—The regular-to-continuous movements of grazers resulted in long periods of veld rest, sometimes even close to one year. Veld rest is important as it ensures seed production and vitality of grasses, particularly good grazing grasses. Continuous grazing is the opposite of this principle.
Low-selectivity grazing—The movement and density of herds "forced" animals to consume almost all grass species, thereby levelling the playing field for competition between palatable and unpalatable species. This is particularly important in high rainfall (sourveld) regions, where the differentiation between palatable and unpalatable grasses is high. The opposite of this principle would be high selectivity grazing, where grazers are spread out and repeatedly graze palatable grasses, thereby decreasing their ability to compete against unpalatable species and preventing them from producing seed.
Short-term trampling—A significant level of short-term heavy trampling took place, particularly in high rainfall (sourveld) regions where herds were large. Although long-term trampling is associated with negative impacts, this short-term trampling has positive impacts. These include breaking soil crusts (for improved water infiltration, aeration and seed germination), removing/managing old grass material (moribund) (which improves nutrient recycling and stimulating new palatable grass growth) and minimising the risk of severe veld fires.
Furthermore, and possibly most important, is that palatable "soft" grasses are better adapted to short-term trampling than unpalatable "brittle" grasses and particularly shrubs. Many argue that the impact on woody samplings by short-term trampling was the main factor, combined with the other principles, that controlled woody shrubs and maintained savanna regions as open landscapes (e.g. Serengeti and Massai Mara).
Predator impact—Large predators had a significant direct and indirect impact on the number and movement of grazers. They were responsible for controlling the number of herbivores to maintain a balance between feed demand and feed supply. During times of drought, with few water points and many weak herbivores, predators will remove a significant number of animals. This reduction in grazing pressure helps the veld to rapidly recover after the drought is broken.
Furthermore, predators prevented grazers from concentrating in one area for too long while their mere presence resulted in animals concentrating in single moving herds. To a large degree, the landowner and the adopted grazing management strategy take up the "responsibility" of predators. The strategy should be to mitigate the negative impacts arising from not having large predators. This comes down to controlling the movement and number of animals.
Dung and urine—The regular movement of nomadic herds resulted in an even spread of dung and urine, thereby fertilising and recycling nutrients evenly in all areas.
A grazing system is a system used to control the movement and density of grazers on the farm. It is said that a grazing system should meet the requirements of the good palatable grazing grasses on the farm as these grasses supply the most nutrients and are consumed to the highest degree. Knowing the different grasses on the farm is therefore fundamental for successful grazing management.
The grazing management strategy and system will differ from farm to farm and is influenced by topography, climatic region, current infrastructure, availability of investment capital and management preferences. A current grazing system can also be improved by, for example, systematically subdividing larger camps over time.
There are a range of basic approaches to grazing systems. This includes continuous grazing (or selective grazing) on the one side of the spectrum, followed by various levels of rotational grazing with ultra-high-density rotational grazing (non-selective grazing) on the other side. The diagram below illustrates the range of approaches with their various features.
A popular approach to simplify grazing management, and to ensure adequate rest is incorporated into the system, is the use of the so-called "block" or "fodder bank" systems. With these systems, the entire grazing area for one group of animals is divided into two or three blocks of approximately equal size. One block is then alternately rested during the growing season while the others are rotationally grazed (see figure 3). The "rest block" is however often grazed once during the mid-growing season to stimulate growth, and then rested again to allow the grasses to grow out, produce seed and save reserve nutrients.
Such a system would then be classified as a high-density grazing system as the animal's graze only half or two-thirds of the grazing area during the growing season. The animal density however depends on the total number of camps available to the group of animals in the system. The more camps available for use, the higher the density of grazing. Such systems are called "fodder bank" systems as the rested block serves as a fodder bank for the dormant season.
A project was recently undertaken on the Firth group farms in the Makwassie area to develop a grazing management strategy based on a scientific approach. This project involved the assessment of the current veld condition and development of grazing systems for each group of animals on the farm, while considering the current infrastructure.
The veld condition assessment was done by collecting data on common grass species, available grass biomass and various veld condition criterion at multiple sites on all farms. This data was then used to estimate the current grazing capacity on each farm. The results have shown that the current veld condition is moderate to good and the grazing capacity on the farms varies from 5,7 ha/LSU to 8,1 ha/LSU. This grazing capacity is slightly higher than the departmental grazing capacity norms for the area, which is 7 – 8 ha/LSU. A high number of good grazing grass species were recorded during the veld assessment (see list below). However, for the most palatable species, the size of tufts was small, and the number of flowering stems was few, indicating room for improvement.
|Species name
|English name
|Afrikaanse naam
|Anthephora pubescens
|Wool grass
|Brachiaria nigropedata
|Black-footed signal grass
|Digitaria eriantha
|Common finger grass
|Gewone vingergras
|Eustachys paspaloides
|Brown Rhodes grass
|Bruin hoenderspoor
|Panicum coloratum
|Small buffalo grass
|Klein buffelgras
|Panicum maximum
|White buffalo grass
|Setaria incrassata
|Vlei bristle grass
|Vlei mannagras
|Setaria nigrirostris
|Vlei bristle grass
|Vlei mannagras
|Setaria sphacelata torta
|Creeping bristle grass
|Kruip mannagras
|Sporobolus fimbriatus
|Common dropseed
|Gewone Fynsaadgras
|Themeda triandra
Based on the current veld condition (many good grasses present), current infrastructure (many available camps) and large size of the farming operation, it was decided to implement a two-block rotational grazing system. This system will supply a bi-annual resting period to blocks, which will increase the number and tuft-size of good grazing grasses. Furthermore, due to an increased herd density, it will decrease selective grazing and provide some level of trampling to break soil crusts and stimulate seed germination.
During a special workshop with some of the farm managers, the various grazing systems for each group of animals on the farms were "designed" using Google Earth software. This involved considering the current grazing capacity, number of herds on each farm and the current infrastructure. In some cases, larger camps were subdivided. Below is an example of one such system (red shaded portion).
During the veld assessments, Reyneke Smit—ecological [land and water usage] manager for the Firth Group—assisted with data collection and learned more about the techniques used. A disc pasture meter was obtained and will be used, together with other methods, to implement a long-term monitoring programme. The results of the monitoring programme will be used to make changes in grazing management if needed.
Modern grazing management principles stem from historic grazing patterns that took place for millennia. In turn, these modern grazing principles shape contemporary—sustainable land usage—grazing management strategies that work well for livestock and game farms. A case study for the successful implementation of these grazing management strategies refers to the Firth Group's cattle and game farms in the Makwassie area of Wolmaransstad.
Business: The Firth Group of Farms (Firth Red Brangus, Firth Wagyu and Hillcrest Game Estates Farms) | Where: Wolmaransstad, North West, South Africa | Website: www.hillcrestgame.co.za

subset: commoncrawl


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|Al Aqsa Martyrs Brigades of Fatah
Mahmoud Abbas' Fatah issued a statement justifying the murder of Jews, although they didn't take credit.
Fatah said in a statement that the Tel Aviv "operation" is a natural response to the "occupation and violations against our people everywhere."
Munir Aljagub, a spokesman, said: "Israel must realize very well the consequences of what they are doing from the continued push towards the option of violence and house demolitions and forced displacement of Jerusalemites and successive intrusions by the settlers to the courtyards of Al-Aqsa Mosque and the Palestinians killed in cold blood in the territories occupied in 1967 ".
At the exact same time, Fatah issued another statement strongly condemning the shooting attack in Jordan that killed 5 soldiers, saying "it is a crime of terrorism par excellence, not only because of a desire for bloody barbarism that drives these shedders of blood, but also to violate the laws and principles of values and ethics of humanity altogether, and the Islamic principles especially, this is the holy month when Islamists slaughter their victims with the idea that it would bring them to paradise."
The moderate Fatah also compared the Muslim Brotherhood, whom they blame for the Jordanian attack, to - you guessed it - Jews, saying "The Brotherhood is characterized by a mentality of revenge and this attribute it identical with its Talmudic twin." (Palestinians may have been responsible for the attack so Fatah wants to blame the Muslim Brotherhood to take the heat off.)
Quite a contrast between how they condemn an attack on a military target and condone an attack on civilians eating dinner. But, you know, those civilians were "Talmudic" and therefore deserved it.
We have lots of ideas, but we need more resources to be even more effective. Please donate today to help get the message out and to help defend Israel.


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New Hunter aligner is 'ACE' solution for workshops – Pro-Align
Pro-Align has launched the latest Hunter wheel alignment system, developed through widespread customer feedback to merge mid-level imaging with a fully upgradable package. The UK distributor told Tyres & Accessories that the new Hunter PA200 ACE has been developed for budget conscious workshops keen to enter the world of premium Hunter four wheel alignment servicing, receiving the best of the American brand's alignment features in a mid-level system – a result of feedback from UK workshops.
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50 Graded Studies for Recorder
50 Graded Studies for Recorder
Arranger: Adams, Sally & Harris, Paul
Department: Recorder
Descant Recorder Repertoire (other publishers)
Publisher: Faber Music
Catalogue No: 0571523188
Shop Product Code: 163391M
$10.65 *
In Stock: Usually despatched within 24-48 hours
* Estimated price converted from UK retail price
This superb book brings together a broad selection of 17th to 20th Century repertory with studies by the likes of Fetzen, van Eyck, Hottetere, Dothel, Gariboldi, Blatt, Tulou and many more. The studies are arranged in order of increasing difficulty.
Published by Faber Music.


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Elegant new Ivory 5x7 and 8x10 Silhouette frame has been added to the PaperPortraits.com frame collection. This frame is really rich and gorgeous looking, made of real wood,
and has a hand gold leafed inner lip.
First Anniversary Wedding Silhouette hand cut by Silhouette Artist Kathryn Flocken.
Framed in 8x10 wood frame, antiqued ivory with hand gold leafed inner lip.
This frame can be found in the PaperPortraits Etsy shop on the side bar of this blog.


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Mikron HSM 700
- Hover over image to enlarge
The high speed spindles, the control system, the feed drives, the axis mechanism and the automation of Mikron's HSM range all have been designed with high speed machining in mind.
High speed milling has never been so easy...
Experience shows that the advantages of high-speed milling can only be realized at cut speeds of more than 40'000 min-1, high feedrates and the best accelerations available – especially in the case of small milling cutter diameters for tool and mould manufacture. These basic requirements call for all the machine components to be fully adapted to HSC technology.
- The original HSM machine
- Highest manufacturing dynamic and speed in this range
- Ideal for quick setup and changing jobs
- Great ergonomics
|X, Y, Z travel
|27.559 x 23.622 x 19.685 in
|Working spindle (40% ED, S6)
|Torque 40% ED
|42 000 (HSK-E40) rpm
|Feed Drives
|Feed _ Rapid speed (X, Y, Z)
|20 / 40 m / min
|Direct drive table
|Clamping surface
|1.3953 x 23.622 (1.395 x 0.93) / 31.496 (69.291) in
|Control unit
|iTNC 530


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Meet the Team
Meet the Shoe Healer family that keep this wonderful business going with their skill and passion for good quality shoes.
Our Heritage
We're very proud of where we come from. We like to believe this shows in our work. It's this passion which got us to where we are today.
Shoe Repairs and Refurbishments
As Cobblers first and foremost, we understand every aspect that goes into the building, ongoing care and repair of your shoes.
Doncaster Town Center (Cobbler & Shoe Room)
The Shoe Healer
42-44 Scot Lane
Doncaster, South Yorkshire
Monday - Saturday, 09:00 to 17:00
Sunday, Closed
South Elmsall (Cobbler)
The Shoe Healer
2B Barnsley Road
South Elmsall
Monday - Saturday, 09:00 to 17:00
Sunday, Closed


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As we are all thrust into 2018, so too do we at Fincham find ourselves thrust into production. With our sights set on the upcoming fifth anthology, we are looking for reviewers to give us their verdict on The Unseen following its official launch in December. Your opinions will help us to make this year's anthology better yet.
Whether you are a literary critic, work for a magazine, or you have a blog, website or even a vlog, we would love to hear from you. If you are interested in reviewing The Unseen, please contact Managing Editor Charlotte Byrne with details of your publication or links to previous reviews. All reviews will receive a special mention on our website and our Facebook and Twitter pages, so this would be a great opportunity to attract new followers.
Of course, you do not need to be an active reviewer to get involved. If you have read The Unseen, you can always leave us a few words about your experience on Amazon or GoodReads. After all, it is the opinions of our readers that we prize most of all.


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Consolidate & Advance Jewellery Making (Stage 4-9)
(+12 more dates)
Continue to advance your jewellery skills.
There is set project work in stages 4 to 9 to advance and consolidate your jewellery making skills as follows:
- Stage 4 - Straight Collet Ring with Facetted Gem.
- Stage 5 - Tappered Collet and Split Shank Ring with Facetted Gem.
- Stage 6 - Facetted Gem Drop Earrings.
- Stage 7 -Large Gem Set Band Ring with Bezels and Edge Wires.
- Stage 8 - Pendant and Chain with surface decoration (roller printing and or hammering) and Gems.
- Stage 9 - Earrings with Set Gems
You design the stage 7 to 9 projects and discuss your proposed fabrication process with the teacher.
For more information on the Stages 4 to 9 and projects please, visit the Contemporary Metal website.
The cost of each Stage is $495.00 (inclusive of GST). There is a consumable charge of $30.00(inclusive of GST) per course which is payable at the commencement of the course.
Silver can be purchased from the studio.
Classes are run on Thursday and Friday (10am to 1.30pm) and Saturday morning (9am to 1pm ) in five- week blocks for 3.5 hours per week.
What you will learn
- Continue to advance your jewellery skills. You must have completed either Stages 1 to 3 or have demonstrated jewellery skills.
- Projects will be developed as a group and individually to accommodate different skill levels. Set projects are detailed below.
- More advanced jewellery making skills.
What you will get
- Your project jewellery.
- More advanced jewellery making skills.
- Skills developed include sawing, soldering, shaping and filing, melting metal, gem setting in various forms, shaping ring shanks, finishing and polishing.
What to bring
- Your interest to learn.
- An apron.
- Research and design drawings for stages 7 to 9.
What to wear
Jeans/long pants, tee shirt, covered shoes and long hair tied back.
Appropriate for
Previous jewellery making skills required.
COVID-19 Risk Mitigation Strategy -Important
Contemporary Metal implemented a COVID-19 RISK Mitigation Strategy in March 2020. Please refer to our Website under Our Policies for detail.
We are a contemporary jewellery studio and gallery run by local jeweller Philip Noakes, who has over forty years experience in making and teaching in the industry. Philip has exhibited extensively around Australia, and makes his own work and private commisions, as well as teaching from the studio.
Contemporary Metal offers jewellers and students access to a fully equipped studio including: rolling mill, soldering and melting torches, pendant drills, vacuum casting, vulcaniser and wax injector, hydraulic press, lathe, tumbler, polisher, ultrasonic, large dapping sets and lapidary equipment.
We have benches available for hire on a casual, weekly or ongoing basis.
Cancellations & Refunds
If the organiser cancels the class:
You are entitled to a transfer or credit note.
If you can't attend the class:
- A refund can be requested 2 days before class starts. An admin fee of AU$20.00 applies.
- A transfer can be requested 2 days before the class starts. Free of charge.
- A credit note can be requested 2 days before the class starts. Free of charge.
No changes will be allowed after these times.
Terms & Conditions
Anyone partaking in any classes or coming to any events at Contemporary Metal or organised by Contemporary Metal must agree to these terms and conditions.
I agree to take on full responsibility for any damages, injuries and for physical and/or personal property, which I might incur whilst participating in classes and/or events organised by Contemporary Metal.
I agree to give Contemporary Metal unrestricted publishing rights for any photographs or videos taken at Contemporary Metal classes and events or on Contemporary Metal's premises. (For use of Contemporary Metal marketing materials).
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AU$155.00Osborne Park, WAWed, 01 May 6:00PM (AWST)
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