Instruct: Given a question, retrieve relevant documents that can help answer the question.
Query: What is the growth rate for human hair?
Scalp hair grows, on average, at a rate of about 1.25 centimeters per month, and shampoos or vitamins have not been shown to noticeably change this rate. Hair growth rate also depends upon what phase in the cycle of hair growth one is actually in; there are three phases. The speed of hair growth varies based upon genetics, gender, age, hormones, and may be reduced by nutrient deficiency (i.e., anorexia, anemia, zinc deficiency) and hormonal fluctuations (i.e., menopause, polycystic ovaries, thyroid disease).
He is a frequent media spokesman, and has written about the importance placed in hair over the centuries and the fact that baldness until recently was not recognised as a social or medical issue, despite the sometimes catastrophic impact it can have on confidence and mental well-being. He wrote: "Male pattern baldness (MPB), the main cause of hair loss, affects an estimated quarter of men by the age of 30 and two thirds by the age of 60. Until recently, the impact baldness might have on confidence and well-being was little understood or recognised by the medical profession at large."
Growth hormone (GH l) is also called somatotropin (British: somatotrophin). The human form of growth hormone is known as human growth hormone, or hGH (ovine growth hormone, or sheep growth hormone, is abbreviated oGH). GH can refer either to the natural hormone produced by the pituitary (somatotropin), or biosynthetic GH for therapy.
Cytoplasmic flows created through osmotic pressure gradients flow longitudinally along the fungal hyphae and crash into the end causing growth. It has been demonstrated that the greater pressure at the hyphal tip corresponds to faster growth rates. Longer hyphae have greater pressure differences along their length allowing for faster cytoplasmic flow rates and larger pressures at the hyphal tip. This is why longer hyphae grow faster than shorter ones. Tip growth increases as cytoplasmic flow rate increases over a 24 hour period until a max rate of 1 micron/second growth rate is observed. Off shoots from the main hyphae are shorter and have slower cytoplasmic flow rates and correspondingly slower growth rates.
Hair, structurally similar to that of modern mammals and associated with bones of the Mongolian multituberculate "Lambdopsalis", has been identified in coprolites (fossilised feces) of carnivorous mammals from the Palaeocene Epoch. This indicates that multituberculates had hair for insulation, similar to modern mammals (and possibly fossil mammals), a feature probably related to homeothermy (warm-bloodedness).
Tanner did early research on the use of human growth hormone to address children whose growth was significantly delayed and was responsible for selecting the small handful of children in the UK who would be treated with the limited supply of HGH extracted from human cadavers. After a number of patients worldwide died in 1985 due to an infectious brain disease spread by the HGH treatments, Tanner immediately stopped the therapy, but had patients who insisted that they were willing to take the risk to address their child's delayed growth. Treatments resumed in the 1990s following the introduction of genetically engineered human growth hormone.
The Ferriman–Gallwey score is a method of evaluating and quantifying hirsutism in women. The method was originally published in 1961 by D. Ferriman and J.D. Gallwey in the "Journal of Clinical Endocrinology".
The original method used 11 body areas to assess hair growth, but was decreased to 9 body areas in the modified method:In the modified method, hair growth is rated from 0 (no growth of terminal hair) to 4 (extensive hair growth) in each of the nine locations. A patient's score may therefore range from a minimum score of 0 to a maximum score of 36. With each ethnic group, the amount of hair expected for that ethnicity should be considered. For example, in Caucasian women, a score of 8 or higher is regarded as indicative of androgen excess.
Henna is an orange dye commonly used as a deposit-only hair color whose active component, lawsone, binds to keratin. It is therefore considered semi-permanent to permanent, depending on a person's hair type. Most people will achieve a permanent color from henna, especially after the second dye. With repeated use the orange color builds up into red and then auburn. While "natural" henna is generally a red color, variations exist. These variations usually contain ingredients from other plants and even synthetic dyes.
Genes for human growth hormone, known as growth hormone 1 (somatotropin; pituitary growth hormone) and growth hormone 2 (placental growth hormone; growth hormone variant), are localized in the q22-24 region of chromosome 17 and are closely related to human chorionic somatomammotropin (also known as placental lactogen) genes. GH, human chorionic somatomammotropin, and prolactin belong to a group of homologous hormones with growth-promoting and lactogenic activity.
Commercially packaged henna, intended for use as a cosmetic hair dye, is available in many countries, and is now popular in India, as well as the Middle East, Europe, Australia, Canada, and the United States. The color that results from dying with henna depends on the original color of the hair, as well as the quality of the henna, and can range from orange to auburn to burgundy. Henna can be mixed with other natural hair dyes including "Cassia obovata" for lighter shades of red or even blond, or with indigo to achieve brown and black shades. Some products sold as "henna" include these other natural dyes. Others may include metal salts that can interact with other chemical treatments, or oils and waxes that may inhibit the dye, or dyes which may be allergens.
Biological exponential growth is the exponential growth of biological organisms. When the resources availability is unlimited in the habitat, the population of an organism living in the habitat grows in an exponential or geometric fashion. Population growth in which the number of individuals increase by a constant multiple in each generation. The potential for population growth can be demonstrated in the laboratory under conditions that provide abundant resources and space. For example, a few fruit flies in a large culture jar containing an abundant food source may reproduce rapidly. One female fruit fly may lay more than 50 eggs. Reproductive adults develop in about 14 days, with approximately equal numbers of male and female offspring. For each female that began the population, 50 flies are expected 2 weeks later. Each female in the second generation produces 50 more flies after 2 more weeks, and so on. In other words, the population is experiencing exponential growth. Slow exponential growth is when a population grows slowly yet exponential because the population has long live spans. While a rapid exponential growth refers to a population that grows ( and dies ) rapidly because the population has short life spans.
Henna only stains the skin one color, a variation of reddish brown, at full maturity 3 days after application.
The Bahá'í religion was ranked by the Foreign Policy magazine as the world's second fastest growing religion by percentage (1.7%) in 2007.
Human growth hormone occurs naturally in the human body. Use of exogenous human growth hormone (HGH), via injection, was originally for medical purposes until athletes began abusing HGH with the goal of increasing their abilities. Before recombinant human growth hormone (rHGH) was developed in 1981, HGH was only available from cadavers. The arrival of rHGH combined with other peptide hormone advancements has increased the availability of HGH on both the legitimate and black markets. The first description of the use of GM as a doping agent was Dan Duchaine’s “Underground Steroid handbook” which emerged from California in 1982; it is not known where and when GM was first used this way. In 1989 the International Olympic Committee became the first to brand human growth hormone a banned substance. Although abuse of human growth hormone for athletic purposes is illegal in the U.S., over the past decade it appears that abuse of HGH is present in all levels of sport. This is fueled at least in part by the fact that HGH is more difficult to detect than most other performance-enhancing drugs, such as anabolic steroids. Athletes competing in power sports, bodybuilding, professional wrestling, mixed martial arts, swimming, baseball, strength sports, track and field, cycling, soccer, weight lifting, skiing and endurance sports have been said to abuse human growth hormone, including in combination with other performance-enhancing drugs such as androgenic anabolic steroids including testosterone, certain products which claim to enhance HGH, and erythropoietin (among others).
200,000 years ago, "Homo sapiens" evolves in East Africa. At the time, "Homo sapiens" was one of many human species, such as Neanderthals. Since 13,000 years ago, "Homo sapiens" has been the only surviving human species. Harari suggests that one of the key reasons why Sapiens is able to take control of the world is Sapiens' advanced language.
According to the CIA - The World Factbook, the country with the highest birth rate currently is Niger at 51.26 births per 1000 people. The country with the lowest birth rate is Japan at 7.64 births per 1000 people. Hong Kong, a Special Administrative Region of China, is at 7.42 births per 1000 people. As compared to the 1950s, birth rate was at 36 births per 1000 in the 1950s, birth rate has declined by 16 births per 1000 people. In July 2011, the U.S. National Institutes of Health announced that the adolescent birth rate continues to decline.
Ethiopia's population has grown from 33.5 million in 1983 to 87.9 million in 2014. The population was only about 9 million in the 19th century. The 2007 Population and Housing Census results show that the population of Ethiopia grew at an average annual rate of 2.6% between 1994 and 2007, down from 2.8% during the period 1983–1994. Currently, the population growth rate is among the top ten countries in the world. The population is forecast to grow to over 210 million by 2060, which would be an increase from 2011 estimates by a factor of about 2.5.
Lagos is, by most estimates, one of the fastest-growing cities in the world. Lagos is currently experiencing a population increase of about 275,000 persons per annum. In 1999 the United Nations predicted that the city's metropolitan area, which had only about 290,000 inhabitants in 1950, would exceed 20 million by 2010 and thus become one of the ten most populated cities in the world.
Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Typically inflammation or scarring is not present. Hair loss in some people causes psychological distress.
Common types include: male-pattern hair loss, female-pattern hair loss, alopecia areata, and a thinning of hair known as telogen effluvium. The cause of male-pattern hair loss is a combination of genetics and male hormones, the cause of female pattern hair loss is unclear, the cause of alopecia areata is autoimmune, and the cause of telogen effluvium is typically a physically or psychologically stressful event. Telogen effluvium is very common following pregnancy.
Less common causes of hair loss without inflammation or scarring include the pulling out of hair, certain medications including chemotherapy, HIV/AIDS, hypothyroidism, and malnutrition including iron deficiency. Causes of hair loss that occurs with scarring or inflammation include fungal infection, lupus erythematosus, radiation therapy, and sarcoidosis. Diagnosis of hair loss is partly based on the areas affected.
Treatment of pattern hair loss may simply involve accepting the condition. Interventions that can be tried include the medications minoxidil (or finasteride) and hair transplant surgery. Alopecia areata may be treated by steroid injections in the affected area, but these need to be frequently repeated to be effective. Hair loss is a common problem. Pattern hair loss by age 50 affects about half of males and a quarter of females. About 2% of people develop alopecia areata at some point in time.
Baldness is the partial or complete lack of hair growth, and part of the wider topic of "hair thinning". The degree and pattern of baldness varies, but its most common cause is androgenic hair loss, "alopecia androgenetica", or "alopecia seborrheica", with the last term primarily used in Europe.
The leaf of the henna plant contains a finite amount of Lawsone molecule. As a result, once the powder has been mixed into a paste, this leaching of dye molecule into the mixture will only occur for an average of 2-6 days. If a paste will not be used within the first few days after mixing, it can be frozen for up to 4 months to halt the dye release, for thawing and use at a later time. Commercially packaged pastes that remain able to stain the skin longer than 7 days without refrigeration or freezing contain other chemicals besides henna that may be dangerous to the skin. After the initial 7 day release of lawsone dye, the henna leaf is spent, therefore any dye created by these commercial cones on the skin after this time period is actually the result of other compounds in the product. These chemicals are often undisclosed on packaging, and have a wide range of colors including what appears to be a natural looking color stain produced by dyes such as Sodium Picramate. These products often do not contain any henna. There are many adulterated henna pastes such as these, and others, for sale today that are erroneously marketed as "natural", "pure", or "organic", all containing potentially dangerous undisclosed additives. The length of time a premanufactured paste takes to arrive in the hands of consumers is typically longer than the 7-day dye release window of henna, therefore one can reasonably expect that any premade mass produced cone that is not shipped frozen is a potentially harmful adulterated chemical variety.
Indigo is natural dye from a plant (Indigofera tinctoria, suffructicosa, or arrecta) that can be added to henna or layered on top of it to create brown to black colors in the hair. Henna is orange, and indigo is blue, so as complementaries on a standard color wheel, the two colors' combined effect is to create brown tones. Like henna, indigo may fade after one application, but it becomes permanent on the hair with repeated use.
Traction alopecia is caused by adding too much strain on the hair on one's head. Tight ponytails and other styles that require added tension to the hair are often what cause this disease. It can also occur on the face in areas where the hair is often styled. Plucking or waxing one's eyebrows frequently, for example, can yield suppressed hair growth in the area.
During the telogen or resting phase (also known as shedding phase) the follicle remains dormant for one to four months. Ten to fifteen percent of the hairs on one's head are in this phase of growth at any given time. In this phase the epidermal cells lining the follicle channel continue to grow as normal and may accumulate around the base of the hair, temporarily anchoring it in place and preserving the hair for its natural purpose without taxing the body's resources needed during the growth phase.
Seasonal changes are also known to affect hair growth. For instance, one experiment had concluded that the rate of hair growth for men and their beards was lowest in January and February and increased from March to July.
The growth of human hair occurs everywhere on the body except for the soles of the feet, the lips, palms of the hands, some external genital areas, the navel, scar tissue, and, apart from eyelashes, the eyelids. Hair is a stratified squamous keratinized epithelium made of multi-layered flat cells whose rope-like filaments provide structure and strength to the hair shaft.