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).

Hair care

Hair care is an overall term for hygiene and cosmetology involving the hair which grows from the human scalp, and to a lesser extent facial, pubic and other body hair. Hair care routines differ according to an individual's culture and the physical characteristics of one's hair. Hair may be colored, trimmed, shaved, plucked or otherwise removed with treatments such as waxing, sugaring and threading. Hair care services are offered in salons, barbershops and day spas, and products are available commercially for home use. Laser hair removal and electrolysis are also available, though these are provided (in the US) by licensed professionals in medical offices or speciality spas.

Care of the hair and care of the scalp skin may appear separate, but are actually intertwined because hair grows from beneath the skin. The living parts of hair (hair follicle, hair root, root sheath and sebaceous gland) are beneath the skin, while the actual hair shaft which emerges (the cuticle which covers the cortex and medulla) has no living processes. Damage or changes made to the visible hair shaft cannot be repaired by a biological process, though much can be done to manage hair and ensure that the cuticle remains intact.

Scalp skin, just like any other skin on the body, must be kept healthy to ensure a healthy body and healthy hair production. If the scalp is cleaned regularly by those who have rough hair or have a hair-fall problem, it can result in loss of hair. However, not all scalp disorders are a result of bacterial infections. Some arise inexplicably, and often only the symptoms can be treated for management of the condition (example: dandruff). There are also bacteria that can affect the hair itself. Head lice is probably the most common hair and scalp ailment worldwide. Head lice can be removed with great attention to detail, and studies show it is not necessarily associated with poor hygiene. More recent studies reveal that head lice actually thrive in clean hair. In this way, hair washing as a term may be a bit misleading, as what is necessary in healthy hair production and maintenance is often simply cleaning the surface of the scalp skin, the way the skin all over the body requires cleaning for good hygiene.

The sebaceous glands in human skin produce sebum, which is composed primarily of fatty acids. Sebum acts to protect hair and skin, and can inhibit the growth of microorganisms on the skin. Sebum contributes to the skin's slightly acidic natural pH somewhere between 5 and 6.8 on the pH spectrum. This oily substance gives hair moisture and shine as it travels naturally down the hair shaft, and serves as a protective substance by preventing the hair from drying out or absorbing excessive amounts of external substances. Sebum is also distributed down the hair shaft "mechanically" by brushing and combing. When sebum is present in excess, the roots of the hair can appear oily, greasy, and darker than normal, and the hair may stick together.

One way to distribute the hair's natural oils through the hair is by brushing with a natural bristle brush. The natural bristles effectively move the oil from the scalp through to the hair's mid-lengths and ends, nourishing these parts of the hair. Brushing the scalp also stimulates the sebaceous gland, which in turn produces more sebum. When sebum and sweat combine on the scalp surface, they help to create the acid mantle, which is the skin's own protective layer.

Washing hair removes excess sweat and oil, as well as unwanted products from the hair and scalp. Often hair is washed as part of a shower or bathing with shampoo, a specialized surfactant. Shampoos work by applying water and shampoo to the hair. The shampoo breaks the surface tension of the water, allowing the hair to become soaked. This is known as the wetting action. The wetting action is caused by the head of the shampoo molecule attracting the water to the hair shaft. Conversely, the tail of the shampoo molecule is attracted to the grease, dirt and oil on the hair shaft. The physical action of shampooing makes the grease and dirt become an emulsion that is then rinsed away with the water. This is known as the emulsifying action. Sulfate free shampoos are less harming on color treated hair than normal shampoos that contain sulfates. Sulfates strip away natural oils as well as hair dye. Sulfates are also responsible for the foaming effect of shampoos.
Shampoos have a pH of between 4 & 6. Acidic shampoos are the most common type used and maintain or improve the condition of the hair as they don't swell the hairshaft and don't strip the natural oils.

Conditioners are often used after shampooing to smooth down the cuticle layer of the hair, which can become roughened during the physical process of shampooing. There are three main types of conditioners: anti-oxidant conditioners, which are mainly used in salons after chemical services and prevent creeping oxidation; internal conditioners, which enter into the cortex of the hair and help improve the hair's internal condition (also known as treatments); and external conditioners, or everyday conditioners, which smooth down the cuticle layer, making the hair shiny, combable and smooth. Conditioners can also provide a physical layer of protection for the hair against physical and environmental damage.

Hair styling equipment which helps in creating hairstyles include:

Cosmetics products used in creating and maintaining hairstyles include:Chemical alterations like perming, coloring can be carried out to change the perceived color and texture of hair. All of these are temporary alterations because permanent alterations are not possible at this time.

Chemical alteration of hair only affects the hair above the scalp; unless the hair roots are damaged, new hair will grow in with natural color and texture.

Hair coloring is the process of adding pigment to or removing pigment from the hair shaft. Hair coloring processes may be referred to as coloring or bleaching, depending on whether pigment is being added or removed.

Temporary hair tints simply coat the shaft with pigments which later wash off.

Most permanent color changes require that the cuticle of the hair be opened so the color change can take place within the cuticle. This process, which uses chemicals to alter the structure of the hair, can damage the cuticle or internal structure of the hair, leaving it dry, weak, or prone to breakage. After the hair processing, the cuticle may not fully close, which results in coarse hair or an accelerated loss of pigment. Generally, the lighter the chosen color from one's initial hair color, the more damaged it may be. Other options for applying color to hair besides chemical dyes include the use of such herbs as henna and indigo, or choosing ammonia-free solutions.

Perms and relaxation using relaxer or thermal reconditioning involve chemical alteration of the internal structure of the hair in order to affect its curliness or straightness. Hair that has been subjected to the use of a permanent is weaker due to the application of chemicals, and should be treated gently and with greater care than hair that isn't chemically altered.

Many industries have requirements for hair being contained to prevent worker injury. This can include people working in construction, utilities, and machine shops of various sorts. Furthermore, many professions require containing the hair for reasons of public health, and a prime example is the food industry. There are also sports that may require similar constraints for safety reasons: to keep hair out of the eyes and blocking one's view, and to prevent being caught in sports equipment or trees and shrubs, or matted hair in severe weather conditions or water. Safety is usually the reason behind not allowing hair to fly loose on the backs of motorcycles and open-topped sports cars for longer tresses.

Scalp skin of babies and the elderly are similar in subdued sebaceous gland production, due to hormonal levels. The sebaceous gland secretes sebum, a waxy ester, which maintains the acid mantle of the scalp and provides a coating that keeps skin supple and moist. The sebum builds overly, between every 2–3 days for the average adult. Those with delicate skin may experience a longer interval. Teenagers often require daily washing of the hair. Sebum also imparts a protective coating to hair strands. Daily washing will remove the sebum daily and incite an increase in sebum production, because the skin notices the scalp skin is lacking sufficient moisture. In cases of scalp disorders, however, this may not be the case. For babies and elderly, the sebaceous gland production is not at peak, thus daily washing is not typically needed.

Split ends, known formally as "trichoptilosis", happen when the protective cuticle has been stripped away from the ends of hair fibers.

This condition involves a longitudinal splitting of the hair fiber. Any chemical or physical trauma, such as heat, that weathers the hair may eventually lead to split ends. Typically, the damaged hair fiber splits into two or three strands and the split may be two to three centimeters in length. Split ends are most often observed in long hair but also occur in short hair that is not in good condition.

As hair grows, the natural protective oils of the scalp can fail to reach the ends of the hair. The ends are considered old once they reach about 10 centimeters since they have had long exposure to the sun, gone through many shampoos and may have been overheated by hair dryers and hot irons. This all results in dry, brittle ends which are prone to splitting. Infrequent trims and lack of hydrating treatments can intensify this condition.

Hair can be damaged by chemical exposure, prolonged or repeated heat exposure (as through the use of heat styling tools), and by perming and straightening. Oil is harmful for rough hair and for dry scalp as it decreases nourishment for hair leading to split and hair fall. When hair behaves in an unusual way, or a scalp skin disorder arises, it is often necessary to visit not only a qualified physician, but sometimes a dermatologist, or a trichologist. Conditions that require this type of professional help include, but are not limited to, forms of alopecia, hair pulling/picking, hair that sticks straight out, black dots on the hair, and rashes or burns resulting from chemical processes.
Gel provides a shiny look but dries the hair and makes it rough.

There are a number of disorders that are particular to the scalp. Symptoms may include:Any of these symptoms may indicate a need for professional assistance from a dermatologist or trichologist for diagnosis.

Scalp skin can suffer from infestations of mites, lice, infections of the follicles or fungus. There could be allergic reactions to ingredients in chemical preparations applied to the hair, even ingredients from shampoo or conditioners. Common concerns surrounding dandruff (often associated with excessive sebum); psoriasis, eczema, or seborrheic dermatitis.

An odor that persists for a few weeks despite regular hair washing may be an indication of a health problem on the scalp skin.

Not all flakes are dandruff. For example, some can merely be product buildup on the scalp skin. This could result from the common practice of applying conditioner to scalp skin without washing. This would dry upon the scalp skin and flake off, appearing like dandruff and even causing itchiness, but have no health effects whatsoever.

There are various reasons for hair loss, most commonly hormonal issues. Fluctuations in hormones will often show in the hair. Not all hair loss is related to what is known as male pattern baldness, women can suffer from baldness just as men do. Formulas for addressing this specific cause of lack of hair growth yet typically they require around three months of consistent use for results to begin to appear. Cessation may also mean that gained growth may dissipate.

Particularly among women, thyroid disease is one of the more under-diagnosed health concerns. Hair falling out in clumps is one symptom of a set of symptoms that may indicate a thyroid concern. In many gynecological exams a blood screen for thyroid is now a common protocol. Thyroid often shows up first in the behavior of the hair.

During pregnancy and breast feeding, the normal and natural shedding process is typically suspended (starting around month three because it takes a while for the body to recognize and reset for the hormonal shifts the body goes through) for the period of gestation and extended longer if one breast feeds (this includes pumping for breast milk). Upon cessation of either of these, it typically takes around two months for the hormones to shift again to the normal hormonal settings, and hair shedding can increase exponentially, for approximately 3–6 months until hair returns to its normal volume. It is commonly noticed that hair seems thicker and shinier, even, during pregnancy and breast feeding in response to the influx of shifting hormones. It is not unusual also for hair color to change, or hair structure to change (e.g., straighter hair, curlier hair). These changes can occur more often than people may realize yet isn't often reported.

Some choose to shave their hair off entirely, while others may have an illness (such as a form of cancer—note that not every form of cancer or cancer treatment necessarily means one will lose their hair) that caused hair loss or led to a decision to shave the head.

Genetics and health are factors in healthy hair. Proper nutrition is important for hair health. The living part of hair is under the scalp skin where the hair root is housed in the hair follicle. The entire follicle and root are fed by a supply of arteries, and blood carries nutrients to the follicle/root. Any time an individual has any kind of health concern from stress, trauma, medications of various sorts, chronic medical conditions or medical conditions that come and then wane, heavy metals in waters and food, smoking etc. these and more can affect the hair, its growth, and its appearance.

Generally, eating a full diet that contains protein, fruits, vegetables, fat, and carbohydrates is important (several vitamins and minerals require fat in order to be delivered or absorbed by the body). Any deficiency will typically show first in the hair. A mild case of anemia can cause shedding and hair loss. Among others, the B group of vitamins are the most important for healthy hair, especially biotin. B (pantothenic acid) gives hair flexibility, strength and shine and helps prevent hair loss and graying. B6 helps prevent dandruff and can be found in cereals, egg yolk and liver. Vitamin B helps prevent the loss of hair and can be found in fish, eggs, chicken and milk.

When the body is under strain, it reprioritizes its processes. For example, the vital organs will be attended to first, meaning that healthy, oxygenated blood may not feed into the hair follicle, resulting in less healthy hair or a decline in growth rate. While not all hair growth issues stem from malnutrition, it is a valuable symptom in diagnosis.

The essential omega-3 fatty acids, protein, vitamin B, and iron, found in fish sources, prevent a dry scalp and dull hair color. Dark green vegetables contain high amounts of vitamins A and C, which help with production of sebum and provide a natural hair conditioner. Legumes provide protein to promote hair growth and also contain iron, zinc, and biotin. Biotin functions to activate certain enzymes that aid in metabolism of carbon dioxide as well as protein, fats, and carbohydrates. A deficiency in biotin intake can cause brittle hair and can lead to hair loss. In order to avoid a deficiency, individuals can find sources of biotin in cereal-grain products, liver, egg yolk, soy flour, and yeast. Nuts contain high sources of selenium and therefore are important for a healthy scalp. Alpha-linolenic acid and zinc are also found in some nuts and help condition the hair and prevent hair shedding that can be caused by a lack of zinc. Protein deficiencies or low-quality protein can produce weak and brittle hair, and can eventually result in loss of hair color. Dairy products are good sources of calcium, a key component for hair growth. A balanced diet is extremely necessary for a healthy scalp and furthermore healthy hair.

The three stages of hair growth are the anagen, catagen, and telogen phases. Each strand of hair on the human body is at its own stage of development. Once the cycle is complete, it restarts and a new strand of hair begins to form. The rate or speed of hair growth is about 1.25 centimetres or 0.5 inches per month, or about 15 centimetres or 6 inches per year.

Human hair growth

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.

The protein called profis makes up hair and stimulates hair growth.

Hair follows a specific growth cycle with three distinct and concurrent phases: anagen, catagen, and telogen. Each phase has specific characteristics that determine the length of the hair.

The body has different types of hair, including vellus hair and androgenic hair, each with its own type of cellular construction. This varied construction gives the hair unique characteristics, serving specific purposes, mainly warmth (redundant in modern humans) and physical protection. Most humans develop the longest thickest hair on their scalps and (mostly observed in males) faces. This hair will usually grow to several feet before terminating, but many humans develop much longer hair.

The anagen phase is known as the growth phase. This is the phase where the hair physically grows approximately 1 cm per month. It begins in the papilla and can last from two to six years. The span at which the hair remains in this stage of growth is determined by genetics. The longer the hair stays in the anagen phase, the longer it will grow. During this phase, cells neighboring the papilla in a germinative layer divide to produce new hair fibers, and the follicle buries itself into the dermal layer of the skin to nourish the strand. About 85% - 90% of the hairs on one's head are in the anagen phase at any given time.

The catagen phase, also known as the transitional phase, allows the follicle to, in a sense, renew itself. During this time, which lasts about two weeks, the hair follicle shrinks due to disintegration and the papilla detaches and "rests," cutting the hair strand off from its nourishing blood supply. Signals sent out by the body (that only selectively affect 1 percent of all hair of one's body at any given time) determine when the anagen phase ends and the catagen phase begins. The first sign of catagen is the cessation of melanin production in the hair bulb and apoptosis of follicular melanocytes. Ultimately, the follicle is 1/6 its original length, causing the hair shaft to be pushed upward. While hair is not growing during this phase, the length of the terminal fibers increase when the follicle pushes them upward.

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.

At some point, the follicle will begin to grow again, softening the anchor point of the shaft initially. The hair base will break free from the root and the hair will be shed. Within two weeks the new hair shaft will begin to emerge once the telogen phase is complete. The process results in normal hair loss known as shedding.

Clinical significance

In most people, scalp hair growth will halt due to follicle devitalization after reaching a length of generally two or three feet. Exceptions to this rule can be observed in individuals with hair development abnormalities, which may cause an unusual length of hair growth.

Most chemotherapy drugs work by attacking rapidly dividing cells. Rapid cell replication is one of the hallmarks of cancer; however, hair follicle cells also grow and divide quickly. Consequently, the chemotherapy drugs usually inhibit hair growth. The dose and type of medicine will determine the severity of hair loss. Once the course of chemotherapy has ended, new hair growth may begin after three to 10 weeks.

Alopecia is a hair loss disease that can occur in anyone at any stage of life. Specifically Alopecia areata is an autoimmune disease that causes hair to spontaneously fall out. It is mainly characterized by bald patches on the scalp or other parts of the body, and can ultimately cause baldness across the entire body. This disease interferes with the hair growth cycle by causing a follicle to prematurely leave the anagen, or active growth, phase and enter the resting, or telogen phase. The hair growth in the affected follicles is lessened or stopped completely.

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.

On the scalp, the hair is usually known to be lost around the hair line, leaving the densest amount of hair at the crown. Small vellus hair will often replace the hair that is lost.

Human hair follicles are very sensitive to the effects of radiation therapy administered to the head, most commonly used to treat cancerous growths within the brain. Hair shedding may start as soon as two weeks after the first dose of radiation and will continue for a couple of weeks. Hair follicles typically enter the resting telogen phase and regrowth should commence 2.5 to 3 months after the hair begins to shed. Regrowth may be sparser after treatment.

UV levels of either 20 or 50 mJ cm in the UV-B range have been shown to inhibit hair growth, reduce hair melanin and damage hair follicles.

A recent development in forensic science is the isotopic analysis of hair strands. Hair has a recognisable growth rate of 9-11mm per month or 15 cm per year. Human hair growth is primarily a function of diet, especially drinking water intake. The stable isotopic ratios of drinking water are a function of location, and the geology that the water percolates through. Sr, Sr and oxygen isotope variations are different all over the world. These differences in isotopic ratio are then biologically'set' in our hair as it grows and it has therefore become possible to identify recent geographic histories by the analysis of hair strands. For example, it could be possible to identify whether a terrorist suspect had recently been to a particular location from hair analysis. This hair analysis is a non-invasive method which is becoming very popular in cases that DNA or other traditional means are bringing no answers.

Isotope analysis

Isotope analysis is the identification of isotopic signature, the abundance of certain stable isotopes and chemical elements within organic and inorganic compounds. Isotopic analysis can be used to understand the flow of energy through a food web, to reconstruct past environmental and climatic conditions, to investigate human and animal diets in the past, for food authentification, and a variety of other physical, geological, palaeontological and chemical processes. Stable isotope ratios are measured using mass spectrometry, which separates the different isotopes of an element on the basis of their mass-to-charge ratio.

Isotopic oxygen is incorporated into the body primarily through ingestion at which point it is used in the formation of, for archaeological purposes, bones and teeth. The oxygen is incorporated into the hydroxylcarbonic apatite of bone and tooth enamel.

Bone is continually remodelled throughout the lifetime of an individual. Although the rate of turnover of isotopic oxygen in hydroxyapatite is not fully known, it is assumed to be similar to that of collagen; approximately 10 years. Consequently, should an individual remain in a region for 10 years or longer, the isotopic oxygen ratios in the bone hydroxyapatite would reflect the oxygen ratios present in that region.

Teeth are not subject to continual remodelling and so their isotopic oxygen ratios remain constant from the time of formation. The isotopic oxygen ratios, then, of teeth represent the ratios of the region in which the individual was born and raised. Where deciduous teeth are present, it is also possible to determine the age at which a child was weaned. Breast milk production draws upon the body water of the mother, which has higher levels of O due to the preferential loss of O through sweat, urine, and expired water vapour.

While teeth are more resistant to chemical and physical changes over time, both are subject to post-depositional diagenesis. As such, isotopic analysis makes use of the more resistant phosphate groups, rather than the less abundant hydroxyl group or the more likely diagenetic carbonate groups present.

Isotope analysis has widespread applicability in the natural sciences. These include numerous applications in the biological, earth and environmental sciences.

Archaeological materials, such as bone, organic residues, hair, or sea shells, can serve as substrates for isotopic analysis. Carbon, nitrogen and zinc isotope ratios are used to investigate the diets of past people; These isotopic systems can be used with others, such as strontium or oxygen, to answer questions about population movements and cultural interactions, such as trade.

Carbon isotopes are analysed in archaeology to determine the source of carbon at the base of the foodchain. Examining the C/C isotope ratio, it is possible to determine whether animals and humans ate predominantly C3 or C4 plants. Potential C3 food sources include wheat, rice, tubers, fruits, nuts and many vegetables, while C4 food sources include millet and sugar cane. Carbon isotope ratios can also be used to distinguish between marine, freshwater, and terrestrial food sources.

Carbon isotope ratios can be measured in bone collagen or bone mineral (hydroxylapatite), and each of these fractions of bone can be analysed to shed light on different components of diet. The carbon in bone collagen is predominantly sourced from dietary protein, while the carbon found in bone mineral is sourced from all consumed dietary carbon, included carbohydrates, lipids, and protein.

To obtain an accurate picture of palaeodiets, it is important to understand processes of diagenesis that may affect the original isotopic signal. It is also important for the researcher to know the variations of isotopes within individuals, between individuals, and over time.

Isotope analysis has been particularly useful in archaeology as a means of characterization. Characterization of artifacts involves determining the isotopic composition of possible source materials such as metal ore bodies and comparing these data to the isotopic composition of analyzed artifacts. A wide range of archaeological materials such as metals, glass and lead-based pigments have been sourced using isotopic characterization. Particularly in the Bronze Age Mediterranean, lead isotope analysis has been a useful tool for determining the sources of metals and an important indicator of trade patterns. Interpretation of lead isotope data is, however, often contentious and faces numerous instrumental and methodological challenges. Problems such as the mixing and re-using of metals from different sources, limited reliable data and contamination of samples can be difficult problems in interpretation.

All biologically active elements exist in a number of different isotopic forms, of which two or more are stable. For example, most carbon is present as C, with approximately 1% being C. The ratio of the two isotopes may be altered by biological and geophysical processes, and these differences can be utilized in a number of ways by ecologists.
The main elements used in isotope ecology are carbon, nitrogen, oxygen, hydrogen and sulfur.

Analysis of the ratio of O to O in the shells of the Colorado Delta clam was used to assess the historical extent of the estuary in the Colorado River Delta prior to construction of upstream dams.

Stable isotopes have become a popular method for understanding aquatic ecosystems because they can help scientists in understanding source links and process information in marine food webs. These analyses can also be used to a certain degree in terrestrial systems. Certain isotopes can signify distinct primary producers forming the bases of food webs and trophic level positioning. The stable isotope compositions are expressed in terms of delta values (δ) in permil (‰), i.e. parts per thousand differences from a standard. They express the proportion of an isotope that is in a sample. The values are expressed as:

where X represents the isotope of interest (e.g., C) and R represents the ratio of the isotope of interest and its natural form (e.g., C/C). Higher (or less negative) delta values indicate increases in a sample's isotope of interest, relative to the standard, and lower (or more negative) values indicate decreases. The standard reference materials for carbon, nitrogen, and sulfur are Pee Dee Belamnite limestone, nitrogen gas in the atmosphere, and Cañon Diablo meteorite respectively. Analysis is usually done using a mass spectrometer, detecting small differences between gaseous elements. Analysis of a sample can cost anywhere from $30 to $100. Stable isotopes assist scientists in analyzing animal diets and food webs by examining the animal tissues that bear a fixed isotopic enrichment or depletion vs. the diet. Muscle or protein fractions have become the most common animal tissue used to examine the isotopes because they represent the assimilated nutrients in their diet. The main advantage to using stable isotope analysis as opposed to stomach content observations is that no matter what the status is of the animal's stomach (empty or not), the isotope tracers in the tissues will give us an understanding of its trophic position and food source. The three major isotopes used in aquatic ecosystem food web analysis are C, N and S. While all three indicate information on trophic dynamics, it is common to perform analysis on at least two of the previously mentioned 3 isotopes for better understanding of marine trophic interactions and for stronger results.

Carbon isotopes aid us in determining the primary production source responsible for the energy flow in an ecosystem. The transfer of C through trophic levels remains relatively the same, except for a small increase (an enrichment < 1 ‰). Large differences of δC between animals indicate that they have different food sources or that their food webs are based on different primary producers (i.e. different species of phytoplankton, marsh grasses.) Because δC indicates the original source of primary producers, the isotopes can also help us determine shifts in diets, both short term, long term or permanent. These shifts may even correlate to seasonal changes, reflecting phytoplankton abundance. Scientists have found that there can be wide ranges of δC values in phytoplankton populations over a geographic region. While it is not quite certain as to why this may be, there are several hypotheses for this occurrence. These include isotopes within dissolved inorganic carbon pools (DIC) may vary with temperature and location and that growth rates of phytoplankton may affect their uptake of the isotopes. δC has been used in determining migration of juvenile animals from sheltered inshore areas to offshore locations by examining the changes in their diets. A study by Fry (1983) studied the isotopic compositions in juvenile shrimp of south Texas grass flats. Fry found that at the beginning of the study the shrimp had isotopic values of δC = -11 to -14‰ and 6-8‰ for δN and δS. As the shrimp matured and migrated offshore, the isotopic values changed to those resembling offshore organisms (δC= -15‰ and δN = 11.5‰ and δS = 16‰).

While there is no enrichment of S between trophic levels, the stable isotope can be useful in distinguishing benthic vs. pelagic producers and marsh vs. phytoplankton producers. Similar to C, it can also help distinguish between different phytoplankton as the key primary producers in food webs. The differences between seawater sulfates and sulfides (c. 21‰ vs -10‰) aid scientists in the discriminations. Sulfur tends to be more plentiful in less aerobic areas, such as benthic systems and marsh plants, than the pelagic and more aerobic systems. Thus, in the benthic systems, there are smaller δS values.

Nitrogen isotopes indicate the trophic level position of organisms (reflective of the time the tissue samples were taken). There is a larger enrichment component with δN because its retention is higher than that of N. This can be seen by analyzing the waste of organisms. Cattle urine has shown that there is a depletion of N relative to the diet. As organisms eat each other, the N isotopes are transferred to the predators. Thus, organisms higher in the trophic pyramid have accumulated higher levels of N ( and higher δN values) relative to their prey and others before them in the food web. Numerous studies on marine ecosystems have shown that on average there is a 3.2‰ enrichment of N vs. diet between different trophic level species in ecosystems In the Baltic sea, Hansson et al. (1997) found that when analyzing a variety of creatures (such as particulate organic matter (phytoplankton), zooplankton, mysids, sprat, smelt and herring,) there was an apparent fractionation of 2.4‰ between consumers and their apparent prey.

In addition to trophic positioning of organisms, δN values have become commonly used in distinguishing between land derived and natural sources of nutrients. As water travels from septic tanks to aquifers, the nitrogen rich water is delivered into coastal areas. Waste-water nitrate has higher concentrations of N than the nitrate that is found in natural soils in near shore zones. For bacteria, it is more convenient for them to uptake N as opposed to N because it is a lighter element and easier to metabolize. Thus, due to bacteria's preference when performing biogeochemical processes such as denitrification and volatilization of ammonia, N is removed from the water at a faster rate than N, resulting in more N entering the aquifer. N is roughly 10-20‰ as opposed to the natural N values of 2-8‰. The inorganic nitrogen that is emitted from septic tanks and other human-derived sewage is usually in the form of NH. Once the nitrogen enters the estuaries via groundwater, it is thought that because there is more N entering, that there will also be more N in the inorganic nitrogen pool delivered and that it is picked up more by producers taking up N. Even though N is easier to take up, because there is much more N, there will still be higher amounts assimilated than normal. These levels of δN can be examined in creatures that live in the area and are non migratory (such as macrophytes, clams and even some fish). This method of identifying high levels of nitrogen input is becoming a more and more popular method in attempting to monitor nutrient input into estuaries and coastal ecosystems. Environmental managers have become more and more concerned about measuring anthropogenic nutrient inputs into estuaries because excess in nutrients can lead to eutrophication and hypoxic events, eliminating organisms from an area entirely.

Isotope analysis can be used by forensic investigators to determine whether two or more samples of explosives are of a common origin. Most high explosives contain carbon, hydrogen, nitrogen and oxygen atoms and thus comparing their relative abundances of isotopes can reveal the existence of a common origin. Researchers have also shown that analysis of the C/C ratios can locate the country of origin for a given explosive.

Stable isotopic analysis has also been used in the identification of drug trafficking routes. Isotopic abundances are different in morphine grown from poppies in south-east Asia versus poppies grown in south-west Asia. The same is applied to cocaine that is derived from Bolivia and that from Colombia.

Stable isotopic analysis has also been used for tracing the geographical origin of food and timber.

We can use the isotopic analysis of water to estimate the proportion of the different sources of water to river etc. Those sources can be rainfall, snow/glacier melt, groundwater etc.

The ratio of O to O in ice and deep sea cores is temperature dependent, and can be used as a proxy measure for reconstructing climate change. During colder periods of the Earth's history (glacials) such as during the ice ages, O is preferentially evaporated from the colder oceans, leaving the slightly heavier and more sluggish O behind. Organisms such as foraminifera which combine oxygen dissolved in the surrounding water with carbon and calcium to build their shells therefore incorporate the temperature-dependent O to O ratio. When these organisms die, they settle out on the sea bed, preserving a long and invaluable record of global climate change through much of the Quaternary. Similarly, ice cores on land are enriched in the heavier O relative to O during warmer climatic phases (interglacials) as more energy is available for the evaporation of the heavier O isotope. The oxygen isotope record preserved in the ice cores is therefore a "mirror" of the record contained in ocean sediments.

Oxygen isotopes preserve a record of the effects of the Milankovitch cycles on climate change during the Quaternary, revealing an approximately 100,000-year cyclicity in the Earth's climate.

Human scalp hair grows on average about one eighth inch per week or one half inch per month. Most clipper guards are numbered in eighths of an inch. The number of the guard denotes the number of weeks of hair growth left on the scalp when a clipper with a certain numbered guard is guided over the head with the guard in contact with the scalp. A #1 guard leaves 1/8 inch (3 mm), one week's growth of hair, on the scalp; a #2 guard leaves 2/8" (6.3 mm), two weeks' hair growth, on the scalp; a #3 guard leaves 3/8" (9 mm), three weeks' hair growth on the scalp; and so on.

Regular haircut

A regular haircut is a men's and boys' hairstyle that has hair long enough to comb on top, a defined or deconstructed side part, and a short, semi-short, medium, long, or extra long back and sides. The style is also known by other names including taper cut, regular taper cut, side-part and standard haircut; as well as short back and sides, business-man cut and professional cut, subject to varying national, regional, and local interpretations of the specific taper for the back and sides.

The short back and sides dates back to the Roman empire, as the regulation haircut for legionaries. Besides preventing the spread of lice, short hair and a clean shaven face prevented the enemy from grabbing a soldier by the beard. By the first century AD, Roman hairstyles were imitated by non-Roman subjects who admired the civilisation that Rome brought. Examples include the Gallo-Romans in occupied France, and Romanised Jews like St Paul seeking to distinguish themselves from traditionalists for whom hair cutting was forbidden.

The regular haircut, worn with a long beard, made a comeback during the Renaissance due to European men's newfound fascination with rediscovered classical artefacts. It was revived for a second time during the Regency era of c.1810-1830 as dandies abandoned the impractical and expensive powdered wigs in response to William Pitt the Younger's hair powder tax.

During the Gay Nineties, the regular haircut gradually replaced the longer hair and muttonchop sideburns fashionable since the 1840s until, by 1910, it had become the norm for professional men. An extreme version known as the undercut was regulation for British and German soldiers during World War I and World War II. The regular haircut remained fashionable in America throughout the 1950s and 1960s due to its association with the upper class Ivy League fashion, and underwent a second revival among the early 1980s preppy subculture in reaction to the androgynous shag and mod haircuts of the 1970s. In the present day, the short back and sides continues to be worn by many professional men, while the related undercut has been appropriated by the hipster subculture.

The essential elements of a regular haircut are edging, and topping:Edging comes first, followed by siding and topping. Edging is typically done with clippers; siding, shears over comb; topping, shears over finger. There are other methods that can be utilized including all clipper cuts, all shears cuts and all razor cuts. Barbers distinguish between a two line haircut and a one line haircut. Two line haircuts are standard taper cuts. The hair is outlined around the ears and then straight down the sides of the neck.The edge of hair growth at the nape of the neck is tapered to the skin with a fine(zero) clipper blade. A one line haircut, often referred to as a block cut, has the edge of hair growth at the nape outline shaved, creating an immediate transition between hair and skin and connecting the outline from the right sideburn to the outline from the left sideburn across the nape. The outline at the edge of the nape can be in a squared off or rounded pattern. A squared off nape can have squared or rounded corners. Rotary, taper and edger clippers can be utilized when edging or siding a haircut. Guards and/or blades can be attached that vary the cutting length.

A tapered back and sides generally contours to the head shape; the hair progressively graduates in length from longer hair at the upper portions of the head to shorter hair at the lower edge of hair growth on the back and sides. There are a variety of tapers possible from short to extra long. Medium and longer tapers can be referred to as trims; however, the word trim is commonly used to request that the hair is trimmed back to the last haircut regardless of the style of taper. The sideburns and the shape and height of the neck edge are important design elements that can affect the appearance of the face, neck, chin, ears, profile and overall style.

In most instances, a shorter neck or chin suits a somewhat higher neck edge; a longer neck or chin suits a somewhat lower neck edge. An extra wide neck suits a somewhat narrower neck edge while a thinner neck or protruding ears suit a wider neck edge. When slightly longer sideburns are worn than are appropriate for a style, it can shorten the appearance of the face; when slightly shorter sideburns are worn than are appropriate, it can lengthen the appearance of the face; therefore, the appearance of a face that is shorter or longer than average, in particular when due to the length of the chin or lower face, can be normalized by altering the length of the sideburns.

Other names for this style of taper include full crown, tight cut, and fade. The hair on the sides and back is cut with a coarse clipper blade from the lower edge of hair growth to or nearly full up to the crown. The clipper is gradually arced out of the hair at the hat band to achieve a taper. A fine clipper is used from the sideburn to about an inch above the ear. Clipper lines are blended out so there is a seamless transition between lengths.

Sideburns, which may not be visible at the time of the haircut depending on the color, thickness and density of the hair, skin tone and fine clipper blade used, are maintained short between haircuts. Short sideburns extend to the area where the ear cartilage attaches to the skull or slightly lower if ear shape requires to allow a sideburn to be defined. Can be worn with a ivy league, high and tight, flat top crew cut, butch and other styles; and often the choice with these styles during the summer.

Also known as a half crown. The hair on the sides and back is cut with a coarse clipper blade about half way up to the crown; the clipper starts to gradually arc out of the hair at the top of the ears. A fine clipper blade is used at the sideburns and at the nape arcing out of the hair to create a blend at a point between the bottom and the top of the ears.

Sideburns are generally worn short as the hair grows out or slightly longer than short but not quite medium. Blending at the upper sides can utilize clipper over comb or shears over comb techniques. While a semi-short taper can be worn with a regular haircut, it is very common with an ivy league, crew cut, flat top crew cut, butch, brush cut, or burr.

A coarse clipper blade may be used on the sideburns, with the clipper immediately arcing out of the hair, completing the taper at the top of the ears. In the nape area, the coarse clipper starts to arc out at the middle of the ears with the taper completed at the top of the ears. A fine clipper blade tapers the lower edge of the hairline at the nape to the skin. The lower edge of hair growth at the nape can alternatively be blocked off in a squared or rounded pattern.

Medium sideburns are appropriate with face shapes that are neither long or short. Medium sideburns extend to the top of the ear orifice. The hair on the middle part of the back and sides can be shortened, thinned and blended using a variety of methods including shears over comb, clipper over comb, thinning shears method, slithering with standard barber's shears, shear point tapering or razor methods. A common style with a regular haircut, medium pompadour or ivy league and also worn with a crew cut or flattop.

A coarse clipper blade is used in the nape area, arcing out of the hair at the bottom of the ears with the taper completed at mid ear. A fine clipper blade is used to taper the edge at the hairline. A long taper is frequently blocked at the nape in a squared or rounded pattern instead of being tapered to the skin. Long sideburns are appropriate for average face shapes. Long sideburns extend to the middle of the ear opening.

The middle section of the back and sides is most often cut shears over comb or shears over fingers; can also be cut with a razor. Thinning, layering and blending of the middle section of the back and sides can be accomplished with thinning shears, slithering or razor techniques. Most frequently worn with a regular haircut or a long pompadour.

A coarse clipper blade is used in the nape, immediately arcing out of the hair, with the taper completed below the bottom of the ears. A fine clipper blade may be used to taper the lower edge of the hairline to the skin. An extra long taper is frequently blocked at the nape in a squared or rounded pattern; a deconstructed arch around the ears and a deconstructed or shaggy block at the nape are also quite common.

Extra long sideburns are appropriate; extra long sideburns extend to the top of the ear lobe. The middle section of the back and sides is most often cut shears over comb or shears over fingers; can also be cut with a razor. Thinning, layering and blending of the middle section of the back and sides can be accomplished with thinning shears, slithering or razor techniques. Apart from being worn with a regular haircut, also worn with an extra long pompadour.

Topping includes shortening, layering, and thinning the hair on the crown and frontal areas to attain the desired length, volume, degree of contour, graduation, and layering. The technique most widely used to shorten, layer and graduate the hair is the shears over finger method, also known as finger work. Finger work involves initially lifting the hair to be cut with the comb, then grasping the lifted hair between the index and middle finger of the opposite hand while transferring the comb to that hand and cutting it with the shears held in the hand that initially held the comb. The comb is then transferred back to the hand that holds the shears and the process is repeated in swaths that go from front to back, outer to inner areas of the right and left sides of the top.

The angle at which the hair is held away from the scalp is critical as it affects how the cut hair will graduate and layer. Depending on the area of the scalp and the desired appearance of the cut hair, the angle will range from around 45 to 135 degrees. Shears over comb techniques include the up and over method and the shear lifting method. In both methods, the hair to be cut is held up by the comb and cut with shears.

The up and over method is a continuous process where the strips of cut hair run from the front hairline back or from the side hairline upwards. In the shear lifitng method, the process is not continuous but carried out sectionally from left to right across the top of the head proceeding from the crown to the front. For example, there may be fifteen separate sections, three across the top of the head from side to side and five from the crown forward. Cutting proceeds from crown left to crown right and so on to front left to front right. As with the shears over finger method, the angle of the hair to the scalp as it is cut is critical to the layered and graduated appearance of the cut hair.

Depending on the thickness of the hair and the desired volume, topping may include thinning which can be accomplished by a variety of methods including thinning shears method, slithering with regular barber shears or the push back method with regular shears or thinning shears. The hair to be thinned may be held with the fingers or comb.
Whorls, cowlicks, and irregularities of the scalp can be addressed by shear point tapering techniques. Only a few hairs are cut in the problem areas using just the tips of the shears, over comb. Topping as well as siding may also be achieved with razor cutting techniques.

Three types of clippers can be utilized to achieve a regular haircut: taper clippers, rotary clippers and outliner/edger clippers. Taper clippers are powered by a linear or pivot motor. The blades are not readily interchangeable. The taper lever allows adjustment of the cutting length within a certain range, usually from #000 blade length, 1/50" (0.5 mm) on the fine side to #1 length, 3/32" (2.4 mm) on the coarse side. For longer lengths, clipper guards are attached. The guard will cut at the numbered guard length when the taper lever is in the shortest cutting position. Clipper guards are also known as clipper guide combs. Fade clippers are identical to taper clippers with the exception of the range of cutting lengths which is entirely within the fine blade range. Most fade clippers cut between #00000 blade length, 1/125" (0.2 mm) and #000 blade length, 1/50" (0.5 mm). As with regular taper clippers, clipper guards can be attached for longer cutting lengths.

Rotary clippers have blades that readily snap on and off. Blades are available that leave from 1/250” (0.1mm) to 3/4” (19mm) of hair on the scalp when the clipper is guided over the head with the teeth of the clipper blade in contact with the scalp. Blades are numbered differently than guards. Rotary clippers are designed to accept a certain standard blade type, so that blades from a variety of manufacturers designed to the specific standard may be utilized on a clipper designed to that standard, regardless of manufacturer. Outliner/edger clippers have a very fine cutting blade and no taper lever and are used to outline a defined arch around the ear and for block cuts, the edge at the nape of the neck.


Who invented velcro?

Swiss electrical engineer George de Mestral invented his first touch fastener when, in 1941, he went for a walk in the woods and wondered why Burdock seeds clung to his coat and dog. He discovered it could be turned into something useful. He patented it in 1955 and subsequently refined and developed its practical manufacture until its commercial introduction in the late 1950s.

Velcro

Velcro BVBA is a privately held company that produces fasteners and other products. It is known for being the original patentor of the hook-and-loop fastener, to which it has (over its objections) lent the generic name "velcro."

The fastener consisted of two components: a lineal fabric strip with tiny hooks that could "mate" with another fabric strip with smaller loops, attaching temporarily, until pulled apart. Initially made of cotton, which proved impractical, the fastener was eventually constructed with nylon and polyester.

De Mestral gave the name "Velcro", a portmanteau of the French words "velour" ("velvet") and "crochet" ("hook"), to his invention as well as his company, which continues to manufacture and market the fastening system.

Velcro


Who was the last King of Portugal?

"Dom" Manuel II (15 November 1889 – 2 July 1932), "the Patriot" () or "the Unfortunate" (), was the last King of Portugal, ascending the throne after the assassination of his father, King Carlos I, and his elder brother, Luís Filipe, the Prince Royal. Before ascending the throne he held the title of Duke of Beja. His reign ended with the dissolution of the monarchy in the 5 October 1910 revolution, and Manuel lived the rest of his life in exile in Twickenham, South London.

Manuel II of Portugal

"Manuel Maria Filipe Carlos Amélio Luís Miguel Rafael Gabriel Gonzaga Francisco de Assis Eugénio de Saxe-Coburgo-Gota e Bragança" was born in the first year of the reign of his father, King Carlos I, the third child and last son born to Carlos I of Portugal and Amélie of Orleans, in the Palace of Belém, Lisbon, less than a month after his father ascended the Portuguese throne. A member of the House of Braganza, he was baptized a few days later, with his maternal grandfather as godfather. The former Emperor Pedro II of Brazil, Manuel II's paternal great-granduncle, who had been deposed from the Brazilian throne on the day of Manuel's birth, attended the ceremony.

He received the traditional education of a member of the royal family, without the political preoccupations that befell his older brother, who was destined to become King. Although Manuel was raised as a member of the upper class, he took a more populist tone after ascending to the throne, and abandoned many of the court protocols. He studied history and languages, and by the age of six spoke and wrote French. He demonstrated a love of literature and reading, unlike his older brother, who was more interested in physical activities. Manuel's upbringing included horse riding, fencing, rowing, tennis and gardening. He was a great lover of music, especially Beethoven and Wagner, and played the piano.

As a child, Manuel played with the children of Count of Figueiró, the children of Count of Galveias and with the rest of the families of the Court. In 1902, he was taught by Franz Kerausch (Latin and German), later by Father João Damasceno Fiadeiro (Portuguese history); Marquês Leitão (Mathematics); M. Boeyé (French and French literature); Alfredo King (English and English literature), Father Domingos Fructuoso (Religion and Morals) and Alexandre Rey Colaço (piano).

In 1903 he traveled with his mother and his brother to Egypt, on board the royal yacht "Amélia", to expand his understanding of ancient civilizations. In 1907, he prepared to enter the Portuguese Naval Academy, to follow a naval career.

His future in the Portuguese Navy was abruptly shelved on 1 February 1908. On that day, the royal family returned from the palace of Vila Viçosa to Lisbon. On their way to the royal palace, the carriage carrying King Carlos and his family passed through the Terreiro do Paço where shots were fired by at least two men: Alfredo Costa and Manuel Buiça. It is unclear whether the assassins were attempting to kill the King, the Prince Royal or the prime minister, João Franco. The murderers were shot on the spot by the royal bodyguard and were later recognized as members of the Portuguese Republican Party. The King was killed; Prince Luís Filipe was mortally wounded; Manuel was hit in the arm; Queen Amélie of Orleans was unharmed. It was Amélie's quick thinking that saved her youngest son. About twenty minutes later, Prince Luis Filipe died, and Manuel became King of Portugal. The young King, who had not been groomed to rule, sought to save the fragile position of the Braganza dynasty by dismissing João Franco and his entire cabinet in 1908. The ambitions of various political parties made Manuel's short reign a turbulent one. In free elections held on 28 August 1910, the republicans won only 14 seats in the legislature.

His first act was to meet with his Council of State and request the resignation of João Franco, whose policies may have been responsible for the tragedy. He appointed a government of national unity, presided over by Admiral Francisco Joaquim Ferreira do Amaral. This quieted the republicans, but in retrospect was seen as weakness.

He opened the Royal Court Assembly on 6 May 1908 in the presence of national representatives, and affirmed his support of the constitution. The King received general public sympathy, due to the deaths of his father and older brother. He was protected by his mother, Amélia, and sought out the support of the experienced politician José Luciano de Castro. Judging that the intervention of King Carlos was a reason for the events of 1908, he declared that he would reign, but not govern.

For his part, the new King tried to increase the monarchy's connection with its subjects. The King visited several areas of the country. His trips included stops in Porto, Braga, Viana do Castelo, Oliveira de Azeméis, Santo Tirso, Vila Nova de Gaia, Aveiro, Guimarães, Coimbra and Barcelos. During these visits, his subjects were captivated by the young king, and he was received warmly. On 23 November he travelled to Espinho in open the Vale do Vouga Railway. On his journeys, he ingratiated himself with the people with his candour and pious character.

However, he was not popular with republicans. One of them, João Chagas, the anti-monarchist journalist and propagandist of the Republican Party, warned the King of the problems that would develop when he declared:

During the 19th century, many intellectuals and politicians were preoccupied with the growth of the urban proletariat as a consequence of the Industrial Revolution. In Portugal, owing to lower levels of industrialisation, this was not an important question, but it was exacerbated by an economic crisis and the Republican Party, who believed a republic would resolve the problems. This was the "Questão Social" (social question) of the times.

The Socialist Party had existed since 1875, but it never had representation in Parliament. This was not only because it was not popular, but also because the Republican Party was the principal channel of radical discontent within the political system. The King made some moves that did not infringe his constitutional restrictions, but which created incentives for the Socialist Party to lessen their support for the Republican Party. In 1909, Manuel invited the French sociologist, Léon Poinsard, to examine the social environment and report back to him. Poinsard wrote that the only way to combat clientelism, created by the system of rotational governments, would be a reorganisation of the local administrations. Enthusiastically, the King wrote to the President of the Council of Ministers Wenceslau de Sousa Pereira de Lima, to make him aware of the reorganisation of the Socialist Party (under Alfredo Aquiles Monteverde) and to remind him of the importance of working with the Socialists, "...so that, we will empty their supporters from the Republican Party, and orient them into a useful and productive force."

Notwithstanding the contacts made by the government of Artur Alberto de Campos Henriques with the Socialist Azedo Gneco, Venceslau de Lima considered this difficult after the Congresso Nacional Operário, which was boycotted by anarchists and republicans. For their part, the Socialists were enthusiastic about Royal support between Manuel and Aquiles Monteverde. Monteverde would later inform the King of the failure of the October 1909 trade union congress, but little was formalised between the socialists and the government, although they supported the work of Poinsard. During the government of António Teixeira de Sousa, in July 1910, that the government created a commission to study the establishment of an Instituto de Trabalho Nacional ("Institute of National Work"), that had three socialists and included Azedo Gneco. However, Aquiles Monteverde would complain that the commission lacked the resources to be effective: specifically that permanent members and unlimited transport, in order for the Socialists to promote their propaganda. Manuel II informed the government, through the Minister of Public Works, that he agreed with the establishment of the Instituto de Trabalho Nacional, but by September, it was too late for the constitutional monarchy.

During his reign he visited many parts of northern Portugal, in addition to Spain, France, and the United Kingdom, where he was appointed Knight of the Order of the Garter, in November 1909. He cultivated a foreign policy that was close to Great Britain, which was not only the geo-political strategy that his father maintained, but it also reinforced his position on the throne by having a strong ally. The court also considered the marriage of a King of the House of Braganza to a British princess would secure the protection of the United Kingdom in any impending conflict. But, the country's instability, the assassination of the King and Prince Royal, and the drawn-out negotiations that were ended with the death of Edward VII, ended these pretensions. The old British monarch, a personal friend of Carlos, would have been the great protector of the House of Braganza, and without him, the liberal government of Britain had no interest in maintaining the Portuguese monarchy.

The stability of the government deteriorated; seven governments were established and fell in a period of 24 months. The monarchist parties continued to fragment, while the Republican Party continued to gain ground. The legislative elections on 28 August 1910 had elected 14 new representatives (resulting in an assembly that was divided: 9% Republican, 58% Government and 33% Opposition) which helped the revolutionary cause, but which made little importance since the Setúbal Congress (on 24–25 April 1909) had determined that the Republicans would take power by force. The murder of a prominent republican precipitated the "coup d'état" that had been so long in coming.

Between 4 and 5 October 1910, the Republican Revolution erupted in the streets of Lisbon. What started as a military coup commenced by soldiers, was joined by some civilians and municipal guards attacking the loyal garrisons and the royal palace, while the guns from the cruiser NRP "Adamastor" added to the cannonade. The Palace of Necessidades (then official residence of the young King) was bombarded, forcing Manuel to move to the Mafra National Palace, where he rendezvoused with his mother, Queen Amélia, and his grandmother, the Queen Mother Maria Pia of Savoy. There was little apparent popular reaction to these events: pictures from the square in front of the City Hall in Lisbon, where the declaration of the Republic occurred, did not show an overwhelming multitude, and even some in the military were fearful that their actions would not be successful. One republican commander, Admiral Cândido dos Reis, even committed suicide when he believed that the events had not succeeded.

One day later, once it was clear that the Republicans had taken the country, Manuel decided to embark from Ericeira on the royal yacht "Amélia IV" for Porto, with armed Republicans arriving as the ship departed. It is unclear whether his advisers motivated Manuel to change his intentions or whether he was forced to change his destination en route, but the Royal Family disembarked in Gibraltar shortly later, after they received notice that Porto had fallen to the Republicans. The coup d'état was complete, and the Royal Family departed for exile, arriving in the United Kingdom, where he was received by the King.

During a visit to Paris in July 1909, the King met Gaby Deslys, an actress and dancer, and immediately began a relationship that would last until the end of Manuel II's reign. It was thought that after this first meeting the King sent Deslys a pearl necklace worth $70,000: more gifts soon followed, including a diamond necklace with black and white pearl drops set in a platinum band. Their relationship was anything but discreet (she would arrive before night at the Palácio das Necessidades and would pass through Portugal unnoticed); abroad, meanwhile, they were on the front pages of newspapers in Europe and North America, especially after he was deposed. In public interviews, usually on trips, Gaby Deslys never negated the obvious, but always refused to comment on her relationship with the King. After his exile, they would continue to meet, especially while she had stage engagements in London. When Gaby moved to New York, in the summer of 1911, their relationship broke off.
In the spring of 1912, Manuel visited Switzerland, where he met Princess Augusta Victoria of Hohenzollern (1890–1966) and was deeply impressed by her. They were second cousins, both being great grandchildren of Ferdinand II of Portugal. In the following year, on 4 September 1913, Manuel married Princess Augusta Victoria, daughter of Prince William, Prince of Hohenzollern. During the mass, which was celebrated in the Chapel of Sigmaringen Castle, Manuel, wearing his Order of the Garter medallion and the sash of the Three Portuguese Orders, stood on a crate containing soil brought from Portugal. The ceremony was conducted by Cardinal José Neto, Patriarch of Lisbon, then exiled in Seville, who had baptized Manuel as a young prince; Manuel was also assisted by the Prince of Wales (Edward VIII) and King Alfonso XIII of Spain, as well as representatives of the royal houses of Europe (including Spain, Germany, Italy, France and Romania, in addition to the principalities and German kingdoms). After festivities which lasted two days, the couple went on their honeymoon to Munich, where the Princess fell ill and withdrew from the public. The marriage, a calm and serene union, lasted until the death of the former King; the couple had no children.

In exile, Manuel resided in Fulwell Park, Twickenham near London (where his mother had been born). At Fulwell Park he tried to recreate a Portuguese environment, as the attempts to restore him to his throne (1911, 1912 and 1919) failed. He was active in the local community, attended services at the Church of St James, Twickenham, and became godfather to several children. In 1932 he donated a window to St James Church bearing the Braganza crest and depicting St Anthony to celebrate the 700th anniversary of the saint’s death. His influence is also recalled by a number of toponymic references in the area: Manuel Road, Lisbon Avenue, and Portugal Gardens. He followed political events in Portugal, and was concerned with the anarchy of the First Republic, fearing that it could provoke a Spanish intervention and risk the country's independence.

While in exile, there was one case where the former King's direct intervention had an effect. After the overthrow of the government of Gomes da Costa, by General Óscar Fragoso Carmona, in 1926, Costa was appointed Ambassador to London. Given the rapid succession of ambassadors during this period, the British government refused to recognize the new official's credentials. As the ambassador was to negotiate the liquidation of the Portuguese debt to the United Kingdom, the Minister of Foreign Affairs asked Manuel to straighten out the situation. The former monarch was delighted by the opportunity to help his homeland and communicated with many of his British contacts (including, probably, King George V) in order to resolve the dispute. Even in exile Manuel continued to be a patriot, going as far as declaring in his 1915 testament his intention to transfer his possessions to the Portuguese State for the creation of a museum, and showing his interest in being buried in Portugal.
Manuel defended the entry of Portugal into the First World War and its active participation. He asked monarchists to desist from restoration efforts as long as the war continued. He even met with republicans, and at one time, solicited his involvement in the Portuguese army. But, contrary to his hopes, a majority of the monarchists did not follow his pleas for cooperation. Many of them backed the aspirations of Germany, and had hoped to see the victory of the Kaiser as another channel to restore the monarchy. Manuel believed that supporting Great Britain would guarantee the retention of overseas colonies, which would have been lost to German aggression even if the Germans were supported in the conflict. Of his close subordinates who offered their support to the Republic, none were accepted.

Manuel attempted to make himself available to the Allies, wherever they saw use, but was disappointed when he was assigned a post in the British Red Cross. He characteristically put all his efforts into the role, participating in conferences, fund drives, visits to hospitals and the wounded soldiers on the front, which ultimately gave him a lot of gratification. The visits to the front were difficult on the French government, but his friendship with George V was sufficient to alleviate their concerns. Regardless, most of his efforts were not credited; years later, in an interview with António Ferro, he lamented, "The operating room in the Portuguese Hospital in Paris, during the War, was constructed by me. Do you know what they put on the plaque? 'From a Portuguese in London'." The King was also responsible for the creation of the Orthopedic Department at Shepherd's Bush Hospital which, at his insistence continued to function until 1925, in order to continue to treat the disfiguring effects of the war. A proof of his recognition by the British was by his friend George V, who invited him to be with the King during the victory celebrations during the parade of soldiers in 1919.

Since 1911, the Portuguese monarchists-in-exile concentrated in Galicia, Spain in order to enter Portugal and restore the monarchy but without the tacit approval of the Spanish government. The monarchists were led by the charismatic Henrique Mitchell de Paiva Couceiro, a veteran of the African colonial campaigns. The "Paladin", as the Portuguese newspapers called him, believed that demonstrating a show of force would force the rural people to rise-up and support the restoration. But he was wrong; poorly prepared and badly financed, his forces encountered apathy from the rural population and the incursions ended with retreats into Galicia.
For his part, Manuel supported these incursions the best way he could, but his financial resources were limited. He also faced a group of monarchists who were not clear supporters of his claim to the throne: one attack was made under a blue and white flag, but without the crown, while Paiva Couceiro himself declared at one time that his movement was "neutral" and wanted a plebiscite on the form of the new regime. It was only after he traded correspondence with Couceiro that the King was able to support the Galician monarchists, who had promised to support the 1826 Constitution. The second incursion, in 1912, although better prepared did not succeed because the Spanish government was forced to cede to Republican diplomats the illegality of monarchist encampments in Galicia and disarmed the remaining combatants within its territory. Manuel was never able to restore his kingdom by force and always defended that the monarchists should organize internally in order to reach power legally (by elections). This was not accepted by militant monarchists who, in the following years, continued their badly prepared attempts to restore the monarchy (for example on 20 October 1914), creating anarchy in the streets. His preoccupation worsened at the beginning of the Great War: Manuel was fearful that the United Kingdom would ally with Spain, in light of Portugal's instability, and that Spain would want to annex Portugal, as the price for Spain's entry into the War.

After the failure of the first monarchist incursion, and with Manuel appearing relatively unenthusiastic for a restoration of the monarchy (and entirely against armed counter-revolution), another group of royalists attempted to legitimize the claims of the descendants of Miguel I to the throne. In order to counter this, the King entered into direct negotiations with the Duke of Braganza's representatives: he attempted to establish himself as the rightful king and, according to the Integralismo Lusitano group, he recognised the descendants of Miguel as being in line to the throne of Portugal. In fact, there was an encounter between Manuel II and Miguel in Dover on 30 January 1912, where both exchanged protocols. The results of this meeting remain controversial: although there was an accord on challenging the republic, there remained no clear agreement on hereditary lines of succession, and Manuel still retained his claim to the throne.

Some monarchists continued unsuccessful counter-revolutionary activities during the War, while the former King continued to condemn their actions and to exhort them to restore the monarchy at the ballot-box. This option seemed viable after the dictatorship of General Pimenta de Castro (January 1915) broke the momentum of the Democratic Party, who attempted to garner sympathies from the conservative right, by removing restrictions imposed on monarchist groups on 5 October. Between April and May 1915, 55 monarchist centres opened (33 in the north and 12 in the centre of the country), causing many republicans to close ranks and on 14 May 1915 the revolution returned to the streets, when 15,000 armed civilians and the soldiers from the Navy tried to maintain the loyalty of the Army to the government. After three days of combat 500 deaths and more than 1,000 wounded, the Democratic Party retained control and the monarchist groups were once again declared illegal. During the Sidónio Pais government, Pais cultivated support from conservative factions and incorporated a re-establishment of a regime based on universal male suffrage. His assassination allowed moderate republicans to re-establish control, but the creation of military juntas in the provinces of the north, with monarchist tendencies, created expectations of a possible monarchist restoration through a military coup d'état.

Manuel continued to plead for calm at the end of the War; while not abandoning the possibility of taking action in the future, he insisted on waiting to the end of peace negotiations in Paris: he was fearful that continued anarchy in Portugal would prejudice its negotiating position. But, for Paiva Couceiro and the other Integralists, this was the moment: they awaited the royal authorization of the King's adjunct Aires de Ornelas. Receiving a memorandum that requested this authorization, and convinced that this action would not occur immediately, Ornelas wrote on the margin, "Go on. Palavras de El-Rei", and signed the document. On 19 January 1919 a thousand soldiers and some artillery, under the command of Paiva Couceiro occupied Porto, in order to restore the Constitutional Monarchy, and its King Manuel II. A provisional government was established that controlled Minho, Trás-os-Montes (with the exception of Chaves), Mirandela and Vila Real), as well as part of the district of Aveiro, but contrary to Couceiro's expectations, the rest of the country did not rise.

In Lisbon, Aires de Ornelas was caught completely by surprise, but he could not escape with other monarchists to the safety of the 2nd Regimental Lancers, in Ajuda. There the number of refugees, who suffered as the republican reprisals increased, and the commander removed his forces and those civilians, marching them to Monsanto, where the 4th, 7th and 9th Cavalry and the 30th Infantry Battery from Belém were entrenched. Aires de Ornelas wavered in his support, which risked the possibility that Integralists would transfer their loyalty to Miguel's supporters, or assume the leadership of the monarchist movement. In a small area, and circled by Republican forces, the monarchists surrendered on 24 January. With the failure of the Restoration in the centre and south of the country, luck turned on Paiva Couceiro. On 13 February a part of the Republican National Guard deserted and restored the Republic in Porto. Those monarchists who did not escape were incarcerated and subsequently sentenced to long-term imprisonment. The King, in exile, did not hear of the failure and was informed only after reading the reports in the newspapers.

Although it is not likely that such a pact will have taken place, it is said that in 1922, with cooling of relations between monarchists, Integralismo Lusitano and the King, and mindful that his marriage to Augusta Victória had not produced heirs, Manuel, in a Paris meeting in April 1922, represented by his adjunct Aires de Ornelas, and Miguelist representatives Infanta Adelgundes, who was by now calling herself Duchess of Guimarães, and tutor to Duarte Nuno, agreed that owing to an heir, the rights of succession would pass to Duarte Nuno. Integralists disagreed because in their view the agreement failed to make reference to the reestablishment of a traditional monarchy, which was fundamental to their assertions. Integralismo Lusitano withheld their support, and on September 1925, Aldegundes in a letter to Manuel, repudiated the agreement owing the continue operation of the Constitutional Newspaper (the Integralist paper was closed as part of the accord) and the lack of Integralist participation.

Manuel was always an avid reader and, during his exile, dedicated himself to the study of literature, penning treatises on Medieval and Renaissance literature in Portugal. Following the First World War and with more free time, apart from his contacts with monarchist organizations, he dedicated himself to these studies (a tradition that was instilled in him by his father). Initially, he was interested in writing a biography, and began research on a biography of Manuel I of Portugal, who he believed was badly treated by other historians. He contracted the services of the bibliographer Maurice Ettinghausen in 1919, to find older books for his project, and was helped by the dissolution of many private collections after the implementation of the Republic.

By 1926, Manuel had abandoned the idea of a biography and concentrated on descriptions of older books in his library (itself, a complete library of older works). More than a simple list, the work allowed Manuel to write of the glories of Portugal, writing not just a bibliography but also an examination of the authors and the context of their writings. His interpretation was scientifically rigorous, and resulted in a final work that was marked by a nationalism and the exaltation of ancestral valor. His examples were limited and illustrated by facsimiled copies of the works, both written in English and Portuguese. The first volume of the work "Livros Antigos Portuguezes 1489–1600, da Bibliotheca de Sua Magestade Fidelíssima Descriptos por S. M. El-Rey D. Manuel em Três volumes" was published in 1929. Manuel delivered, by hand, a copy of his work to his friend George V at Windsor Castle. The work was received well by critics, and the King dedicated himself to the second volume, which covered the period 1540 to 1569. But the project was terminated prematurely in 1932, when Manuel died unexpectedly: the third volume was posthumously published under the supervision of his librarian, Margery Winters. His completed works gave the King a respectful reputation among Portuguese historians, and his bust was added to the entrance atrium of the National Library in Lisbon.

Manuel died unexpectedly in his residence on 2 July 1932, via suffocation by an abnormal swelling in the vocal folds of his larynx, or tracheal oedema. The Portuguese government, at that time led by António Oliveira de Salazar, authorized his burial in Lisbon, after a state funeral. His body arrived in Lisbon on 2 August 1932, on board the British cruiser HMS "Concord" which had made the journey from the United Kingdom and sailed into the Tagus River to deliver the coffin of the former King. The body was received at Praça do Comércio, where a crowd of people had gathered to follow the coffin to São Vicente de Fora and the roads were inundated with people interested in seeing the funeral procession. His body was interred in the Royal Pantheon of the House of Braganza in the Monastery of São Vicente de Fora.

By some he was given the nickname "O Patriota" ('The Patriot'), for his preoccupation with the national identity; "O Desventurado" ('The Unfortunate'), because he lost his throne to the Republic; and "O Estudioso" or "O Bibliófilo" ('The Studious' or 'The Bibliophile') for his love for Portuguese literature. Monarchists also referred to him as "O Rei-Saudade" ('The Missed King'), for the longing that was felt when the monarchy was abolished.

His death has been regarded as suspicious by some because of the fact that he had been playing tennis on 1 July and was apparently in excellent health. An incident surrounding his sudden death was mentioned in the autobiography of Harold Brust, a member of Scotland Yard Special Branch in charge of protecting public figures. In his memoirs, Brust speaks of an incident which probably occurred in 1931 in which an intruder was discovered in the grounds of Fulwell Park who, when arrested, the Police confirmed as being a prominent member of a Portuguese republican terrorist group known as the Carbonária and who was subsequently deported to Lisbon. To date the identity of the intruder has not been confirmed. Questions remain as to the reason for the man's intrusion.

Since both the Dover and Paris Pacts did not resolve the issue of succession and there are no known documents proving them, there was no direct heir to the defunct throne. Manuel also made it clear that the branches of the Portuguese royal family (including the Imperial family of Brazil, the Braganza-Orleans, and the descendants of the Duke of Loulé) ended with the last direct male heir to the House of Braganza. Still, the monarchist Integralismo Lusitano movement acclaimed Duarte Nuno, Duke of Braganza as King of Portugal, since Miguel I of Portugal, on the death of his grandchild, was head of the Portuguese Royal Family. Their justification, ironically, included the fact that both branches had met to determine the line of succession in Dover and Paris, even though those accords were both later repudiated.

After King Manuel's death, the dictator António de Oliveira Salazar authorized the return of the banned branch of the Braganças (ex-King Miguel's descendents) and founded, with the sale of the King's English estate and some of his remaining personal possessions, the Foundation of the House of Braganza, according to King Manuel's desire to leave his personal fortune to the Portuguese people.