scientific journals in publication, and many more have been published at various points in the past (see list of scientific journals). Most journals are highly
or scholarly journal is a periodical publication in which scholarship relating to a particular academic discipline is published. Academic journals serve
often called "grey literature". Most scientific and scholarly journals, and many academic and scholarly books, though not all, are based on some form of
Research Network or SSRN Electronic Journal: Economics Elsevier (SSRN), is a website devoted to the rapid dissemination of scholarly research in the social
Electronic articles are articles in scholarly journals or magazines that can be accessed via electronic transmission. They are a specialized form of electronic
a government at the beginning of 2017. NPOS aims to promote open access to scholarly literature and re-use of research data and has appointed the ex-Rector
Access Journals List of open access journals(Category) Mega journal Open access mandate Open Access Scholarly Publishers Association Overlay journal Predatory
Press publishes books, journals, and electronic databases. Considering all its units (books, journals, fulfillment, and electronic resources) it is a contender
academic journals Directories and Lists of Electronic Journals and Newsletters ScholarlyJournals Distributed Via the World Wide Web Scientific Journals publishing
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Jurn (category Full text scholarly online databases)
full-text scholarly works. It was established in a public online open beta version in February 2009, initially for finding open access electronic journal articles
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Project MUSE (category Full text scholarly online databases)
launched online alongside the JHU Press Journals in 1995. Beginning in 2000, journals from other scholarly publishers were integrated into MUSE’s online
(Scientific Electronic Library Online) is a bibliographic database, digital library, and a cooperative electronic publishing model of open access journals. SciELO
intellectual assets. Common methods of scholarly communication include writings in scholarly journals, books, E-only journals, reviews, preprints, and working
the Berkeley Electronic Press, co-founded by academics Robert Cooter and Aaron Edlin. It makes products and services to support scholarly communication
online academic journals and books, conference papers, theses and dissertations, preprints, abstracts, technical reports, and other scholarly literature,
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Behavioural and social sciences
1. BEHAVIOURAL AND SOCIAL SCIENCES
2. Social environment is as important as the physical and biological environment in relation to health and disease in man. The term social environment denotes the complex of psychosocial factors influencing the health of the individual and the community INTRODUCTION: SOCIAL SCIENCES: 5 SOCIAL SCIENCES INCLUDE SOCIOLOGY CULTURAL ANTHROPOLOGY SOCIAL PSYCHOLOGY ECONOMICS POLITICAL SCIENCE BEHAVIOURAL SCIENCES
3. SOCIOLOGY: IT IS THE SCIENCE CONCERNED WITH THE ORGANIZATION OF STRUCTURE OF SOCIAL GROUPS. It is the science of behavior of man in a society or group of human beings. Society is a group of people who must be mentally aware of each other. Sociologists define society as “ a system of uses and procedures of authority and mutual aid of many groups coupled with division of control of human behavior and liberty”.
4. FUNCTIONAL ASPECTS OF SOCIETY: A. Social norms --- Folkways # Mores # Taboo B. Customs and habits C. Etiquettes and conventions D. Social values STRUCTURAL ASPECTS OF SOCIETY: ------} Social institution ------} Community ------} Association
5. CULTURAL ANTHROPOLOGY: Branches of cultural anthropology are; -- ethnology -- archeology -- linguistics -- social anthropology SOCIAL PSYCHOLOGY ECONOMICS POLITICAL SCIENCES
6. HEALTH BEHAVIOUR AND LIFE STYLE: “Any activity undertaken by an individual, regardless of actual or perceived health status, for the purpose of promoting, protecting or maintaining health, whether or not such behavior is objectively effective towards that end”. ILLNESS BEHAVIOR LABELING BEHAVIOR Factors influencing preventive behavior: 1} growth and development 2} family and peer influence 3} past medical and dental experiences 4} dental office environment
7. THEORIES OF BEHAVIOR CHANGE: 1.HEALTH BELIEF MODEL 2.MULTI DIMENSIONAL HEALTH LOCUS OF CONTROL 3.STAGES OF CHANGE MODEL
8. BARRIERS TO ACHIEVING BEHAVIOR CHANGE: 1.Lack of opportunity 2.Lack of resources 3.Lack of support 4.Conflicting motives 5.Long term nature of benefit 6.Belief that change not possible 7.No clearly defined goals 8.Lack of knowledge on what to change
9. LIFE STYLE AND ORAL HEALTH: “Lifestyle is a way of living based on identifiable patterns of behavior, which are determined by the interplay between an individual’s personal characteristics, social interactions, and socioeconomic and environmental living conditions”. Life style interventions must be based on the co operation and full participation of the individuals and groups concerned , since if they were dominated by professionals, they would not be health promoting Ethical issues in life style in terventions: 1. Privacy 2. Anxiety 3. Confidentiality 4. Choices
10. Social stratification and oral health: The common characteristics of social groups are: 1.There is a sense of unity and belonging 2.They have a we-feeling and help each other 3.They have common objectives and interests 4.Each group ha sits own code of conduct and behavior 5.Every member of the group is expected to follow its norms
11. Types of groups: The word ‘group’ may be defined as a gathering of two or more people who have a common interest. Groups can be classified as : 1. Primary group 2. Secondary group 3. Reference groups Groups can also be classified as: 1. Formal group 2. Informal group
12. Formal groups Informal groups Well organized Not organized Have a purpose or goal People come and go at will Set memberships No membership or a feeling of belonging Have recognized leaders No special activity is planned by the people Have definite rules No rules apply Have regular meetings There is no leader Attention is paid for the welfare of the members There is more concern for the self and less for those of other people present E.g.; dental association e.g. a gathering of patient at a clinic
13. Socialization is a process which enables an individual to take part in group life and acquire many of the characteristics thought of as human. Socialization takes place within groups Theoretical explanations of social inequalities in oral health: The black report ( Blane, 1985) considered 4 possible explanations for the existence of a gradient between health and social class. 1. Artifact explanations 2. The social selection explanation (or natural explanation) 3. The materialist( or structuralist) 4. Cultural (or behavioural ) explanations
14. Social science in dental public health: When applied to a practical problem such as dental program planning, social science in effect adds a new dimension to the process of surveying and evaluation. The social scientist becomes necessary when we want to know why effort and effect do not match each other. Studies by behavioral scientists have resulted in the description of certain social classes and the reaction of each to dental care. They are, 1. The upper middle class 2. The lower middle class 3. The upper lower class 4. The lower class
15. Trithart in 1968 has summarized the attitudes of the under privileged people toward health care, in the following listing; 1. Contradiction of common sense 2. Coming in crowds 3. The last ditch effort 4. If it hurts, you are a quack 5. Unclean or dirty feeling 6. The clinic was built there, not here 7. Cold professional attitudes 8. Difference in pain threshold 9. Complication of the unknown 10.The pills don’t work 11.Appointments are not important 12.Teeth lost anyhow 13.Traditions
16. Risk behavior: Risk behaviors are specific forms of behavior which are proven to be associated with increased susceptibility to a specific disease or ill heath Risk factor: Risk factors are social, economic or biological status, behaviors or environments which are associated with or cause increased susceptibility to a specific disease, ill health , or injury
17. Harmful dental health behaviors: 1. Alcohol use 2. Smoking 3. Nutrition 4. Drug use Utilization of dental services: Utilization is the actual attendance by members of the public at health care facilities to receive care. The factors which influence an individual to utilize a health service are, 1. Individual must feel susceptible to the disease 2. Individual must feel that the disease is potentially serious in its effects in regard to him 3. Individual must feel that a course of action that will prevent or alleviate the disease is available to him
18. Need for dental care: The different types of need for dental care are, a)Normative need b)Felt need c)Expressed need The four different approaches to estimating need are, 1.Surveys of dental health status 2.Surveys of need for dental care using questionnaires 3.Analyses of service or treatment records
19. Physiologic needs : hunger, thirst, fear. Security: need 4 shelter and employment. Social needs: need to be loved. Esteem : need to personal worth, competency and skills. Self-actualization: need to realize one.
21. Factors affecting utilization: 1.Age 2.Sex 3.Education 4.Socio- economic status 5.Occupation 6.Residence 7.Socio- cultural factors 8.Organizational factors 9.Cost of health services
22. Behavior of the child in the dental office: Psychodynamic theories a)Classical psychoanalytical theory by sigmund freud b)Developmental tasks theory by erik erikson Behavior learning theories 1.Classical conditioning theory by ivan pavlov 2.Operant conditioning theory by b.f. skinner 3.Theory of cognitive development by jean piaget 4.Social learning theory by albert bandura
23. According to this the reinforcements are considered to be facilitative rather than being associated with learning. Behavior is largely motivated by social needs SOCIAL LEARNING ALBERT BANDURA (1963)
24. Behavior management is as much an art form, as it is a science. Communicative management is used universally for both the cooperative and uncooperative child. The specific techniques associated with this process are: 1. Voice control 2. Non verbal communication 3. Tell show do 4. Modelling 5. Positive reinforcement 6. Systematic desensitization 7. Distraction 8. Parental presence or absence 9. HOME { Hand over mouth exercise}
scientists and scholars to publish the fruits of their research in scholarly journals without payment, for the sake of inquiry and knowledge. The new technology
very expensive journals and some of that going on. And open source is making a comeback in science with things like arXiv and open journals. Wikipedia changed
Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by the availability of food. It occurs mainly in the northern hemisphere, where birds are funneled on to specific routes by natural barriers such as the Mediterranean Seaor the Caribbean Sea.
More recently, Johannes Leche began recording dates of arrivals of spring migrants in Finland in 1749, and modern scientific studies have used techniques including bird ringing and satellite tracking to trace migrants. Threats to migratory birds have grown with habitat destruction especially of stopover and wintering sites, as well as structures such as power lines and wind farms.
The Arctic tern holds the long-distance migration record for birds, traveling between Arctic breeding grounds and the Antarctic each year. Some species of tubenoses (Procellariiformes) such as albatrosses circle the earth, flying over the southern oceans, while others such as Manx shearwaters migrate 14,000 km (8,700 mi) between their northern breeding grounds and the southern ocean. Shorter migrations are common, including altitudinal migrations on mountains such as the Andes and Himalayas.
The timing of migration seems to be controlled primarily by changes in day length. Migrating birds navigate using celestial cues from the sun and stars, the earth's magnetic field, and mental maps.
Migration is the regular seasonal movement, often north and south, undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat, or weather. Sometimes, journeys are not termed "true migration" because they are irregular (nomadism, invasions, irruptions) or in only one direction (dispersal, movement of young away from the natal area). Migration is marked by its annual seasonality. Non-migratory birds are said to be resident or sedentary. Approximately 1800 of the world's 10,000 bird species are long-distance migrants.
Many bird populations migrate long distances along a flyway. The most common pattern involves flying north in the spring to breed in the temperate or Arctic summer and returning in the autumn to wintering grounds in warmer regions to the south. Of course, in the southern hemisphere, the directions are reversed, but there is less land area in the far south to support long-distance migration.
The primary motivation for migration appears to be food; for example, some hummingbirds choose not to migrate if fed through the winter. Also, the longer days of the northern summer provide extended time for breeding birds to feed their young. This helps diurnal birds to produce larger clutches than related non-migratory species that remain in the tropics. As the days shorten in autumn, the birds return to warmer regions where the available food supply varies little with the season.
These advantages offset the high stress, physical exertion costs, and other risks of the migration. Predation can be heightened during migration: Eleonora's falconFalco eleonorae, which breeds on Mediterranean islands, has a very late breeding season, coordinated with the autumn passage of southbound passerine migrants, which it feeds to its young. A similar strategy is adopted by the greater noctule bat, which preys on nocturnal passerine migrants. The higher concentrations of migrating birds at stopover sites make them prone to parasites and pathogens, which require a heightened immune response.
Within a species not all populations may be migratory; this is known as "partial migration". Partial migration is very common in the southern continents; in Australia, 44% of non-passerine birds and 32% of passerine species are partially migratory. In some species, the population at higher latitudes tends to be migratory and will often winter at lower latitude. The migrating birds bypass the latitudes where other populations may be sedentary, where suitable wintering habitats may already be occupied. This is an example of leap-frog migration. Many fully migratory species show leap-frog migration (birds that nest at higher latitudes spend the winter at lower latitudes), and many show the alternative, chain migration, where populations 'slide' more evenly north and south without reversing the order
Within a population, it is common for different ages and/or sexes to have different patterns of timing and distance. Female chaffinchesFringilla coelebs in Eastern Fennoscandia migrate earlier in the autumn than males do and the European tits of genera Parus and Cyanistes only migrate their first year.
Most migrations begin with the birds starting off in a broad front. Often, this front narrows into one or more preferred routes termed flyways. These routes typically follow mountain ranges or coastlines, sometimes rivers, and may take advantage of updrafts and other wind patterns or avoid geographical barriers such as large stretches of open water. The specific routes may be genetically programmed or learned to varying degrees. The routes taken on forward and return migration are often different. A common pattern in North America is clockwise migration, where birds flying North tend to be further West, and flying South tend to shift Eastwards.
Many, if not most, birds migrate in flocks. For larger birds, flying in flocks reduces the energy cost. Geese in a V-formation may conserve 12–20% of the energy they would need to fly alone. Red knots Calidris canutus and dunlins Calidris alpina were found in radar studies to fly 5 km/h (3.1 mph) faster in flocks than when they were flying alone.
Northern pintail skeletons have been found high in the Himalayas
Birds fly at varying altitudes during migration. An expedition to Mt. Everest found skeletons of northern pintailAnas acuta and black-tailed godwitLimosa limosa at 5,000 m (16,000 ft) on the Khumbu Glacier.[30]Bar-headed geeseAnser indicus have been recorded by GPS flying at up to 6,540 metres (21,460 ft) while crossing the Himalayas, at the same time engaging in the highest rates of climb to altitude for any bird. Anecdotal reports of them flying much higher have yet to be corroborated with any direct evidence. Seabirds fly low over water but gain altitude when crossing land, and the reverse pattern is seen in landbirds. However most bird migration is in the range of 150 to 600 m (490 to 1,970 ft). Bird strike aviation records from the United States show most collisions occur below 600 m (2,000 ft) and almost none above 1,800 m (5,900 ft).
Bird migration is not limited to birds that can fly. Most species of penguin(Spheniscidae) migrate by swimming. These routes can cover over 1,000 km (620 mi). Dusky grouseDendragapus obscurus perform altitudinal migration mostly by walking. EmusDromaius novaehollandiae in Australia have been observed to undertake long-distance movements on foot during droughts.
Nocturnal migratory behavior
While participating in nocturnal migration, many birds give 'Nocturnal Flight Calls', which are short, contact-type calls. These calls likely serve to maintain the composition of a migrating flock, and can sometimes encode the gender of a migrating individual. They also likely serve to avoid a collision in the air. Nocturnal migration can also be monitored using weather radar data, which can be used to estimate the number of birds migrating on a given night, as well as the direction of the migration. Future research in this field includes the automatic detection and identification of nocturnally calling migrant birds, which could have broad implications on species conservation and land management.
Nocturnal migrants land in the morning and may feed for a few days before resuming their migration. These birds are referred to as passage migrants in the regions where they occur for a short duration between the origin and destination.
Nocturnal migrants minimize depredation, avoid overheating, and can feed during the day. One cost of nocturnal migration is the loss of sleep. Migrants may be able to alter their quality of sleep to compensate for the loss.
Long-distance migration
The United States and the American goldfinch from taiga to wintering grounds extending from the American South northwestward to Western Oregon. Some ducks, such as the garganeyAnas querquedula, move completely or partially into the tropics. The European pied flycatcherFicedula hypoleuca also follows this migratory trend, breeding in Asia and Europe and wintering in Africa.
Migration routes and wintering grounds are both genetically and traditionally determined depending on the social system of the species. In long-lived, social species such as white storks(Ciconia ciconia), flocks are often led by the oldest members and young storks learn the route on their first journey. In short-lived species that migrate alone, such as the Eurasian blackcapSylvia atricapilla or the yellow-billed cuckooCoccyzus americanus, first-year migrants follow a genetically determined route that is alterable with selective breeding.
Often, the migration route of a long-distance migratory bird doesn't follow a straight line between breeding and wintering grounds. Rather, it could follow a hooked or arched line, with detours around geographical barriers or towards suitable stopover habitat. For most land-birds, such barriers could consist of seas, large water bodies or high mountain ranges, a lack of stopover or feeding sites, or a lack of thermal columns (important for broad-winged birds). Additionally, many migration routes are circuitous due to evolutionary history: the breeding range of Northern wheatearsOenanthe oenanthe has expanded to cover the entire Northern Hemisphere, but the species still migrates up to 14,500 km to reach ancestral wintering grounds in sub-Saharan Africa rather than establish new wintering grounds closer to breeding areas.
The same considerations about barriers and detours that apply to long-distance land-bird migration apply to water birds, but in reverse: a large area of land without bodies of water that offer feeding sites may also be a barrier to a bird that feeds in coastal waters. Detours avoiding such barriers are observed: for example, brent geese Branta bernicla migrating from the Taymyr Peninsula to the Wadden Sea travel via the White Sea coast and the Baltic Sea rather than directly across the Arctic Ocean and northern Scandinavia.
Many bird species arid regions across southern Australia are nomadic; they follow water and food supply around the country in an irregular pattern, unrelated to the season but related to rainfall. Several years may pass between visits to an area by a particular species.
Bird migration is primarily, but not entirely, a Northern Hemisphere phenomenon. This is because land birds in high northern latitudes, where food becomes scarce in winter, leave for areas further south (including the Southern Hemisphere) to overwinter, and because the continental landmass is much larger in the Northern Hemisphere. In contrast, among (pelagic) seabirds, species of the Southern Hemisphere are more likely to migrate. This is because there is a large area of ocean in the Southern Hemisphere, and more islands suitable for seabirds to nest.
Physiology and control
The control of migration, its timing and response are genetically controlled and appear to be a primitive trait that is present even in non-migratory species of birds. The ability to navigate and orient themselves during migration is a much more complex phenomenon that may include both endogenous programs as well as learning.
Timing
The primary physiological cue for migration are the changes in the day length. These changes are also related to hormonal changes in the birds. In the period before migration, many birds display higher activity or Zugunruhe (German: migratory restlessness), first described by Johann Friedrich Naumann in 1795, as well as physiological changes such as increased fat deposition. The occurrence of Zugunruhe even in cage-raised birds with no environmental cues (e.g. shortening of day and falling temperature) has pointed to the role of circannual endogenous programs in controlling bird migrations. Caged birds display a preferential flight direction that corresponds with the migratory direction they would take in nature, changing their preferential direction at roughly the same time their wild conspecifics change course.
In polygynous species with considerable sexual dimorphism, males tend to return earlier to the breeding sites than their females. This is termed protandry.
Orientation and navigation
The routes of satellite tagged bar-tailed godwits migrating north from New Zealand. This species has the longest known non-stop migration of any species, up to 10,200 km (6,300 mi).
Navigation is based on a variety of senses. Many birds have been shown to use a sun compass. Using the sun for direction involves the need for making compensation based on the time. Navigation has also been shown to be based on a combination of other abilities including the ability to detect magnetic fields (magnetoception), use visual landmarks as well as olfactory cues.
Long distance migrants are believed to disperse as young birds and form attachments to potential breeding sites and to favorite wintering sites. Once the site attachment is made they show high site-fidelity, visiting the same wintering sites year after year.
The ability of birds to navigate during migrations cannot be fully explained by endogenous programming, even with the help of responses to environmental cues. The ability to successfully perform long-distance migrations can probably only be fully explained with an accounting for the cognitive ability of the birds to recognize habitats and form mental maps. Satellite tracking of day migrating raptors such as ospreys and honey buzzards has shown that older individuals are better at making corrections for wind drift. The birds navigate through an innate biological sense resulting from evolution. Migratory birds may use two electromagnetic tools to find their destinations: one that is entirely innate and another that relies on experience.
A young bird on its first migration flies in the correct direction according to the Earth's magnetic field but does not know how far the journey will be. It does this through a radical pair mechanism whereby chemical reactions in special photo pigments sensitive to short wavelengths are affected by the field. Although this only works during daylight hours, it does not use the position of the sun in any way. At this stage, the bird is in the position of a Boy Scout with a compass but no map, until it grows accustomed to the journey and can put its other capabilities to use. With experience, it learns various landmarks and this "mapping" is done by magnetites in the trigeminal system, which tell the bird how strong the field is. Because birds migrate between northern and southern regions, the magnetic field strengths at different latitudes let it interpret the radical pair mechanism more accurately and let it know when it has reached its destination. There is a neural connection between the eye and "Cluster N", the part of the forebrain that is active during migrational orientation, suggesting that birds may actually be able to see the magnetic field of the earth.
Migrating birds can lose their way and appear outside their normal ranges. This can be due to flying past their destinations as in the "spring overshoot" in which birds returning to their breeding areas overshoot and end up further north than intended. Certain areas, because of their location, have become famous as watchpoints for such birds. Examples are the Point Pelee National Park in Canada, and Spurn in England.
Reverse migration, where the genetic programming of young birds fails to work properly, can lead to rarities turning up as vagrants thousands of kilometres out of range-
Drift migration of birds blown off course by the wind can result in "falls" of large numbers of migrants at coastal sites.
A related phenomenon called "abmigration" involves birds from one region joining similar birds from a different breeding region in the common winter grounds and then migrating back along with the new population. This is especially common in some waterfowl, which shift from one flyway to another.
Migration conditioning
It has been possible to teach a migration route to a flock of birds, for example in re-introduction schemes. After a trial with Canada geeseBranta canadensis, microlight aircraft were used in the US to teach safe migration routes to reintroduced whooping cranesGrus americana.
Adaptations
Birds need to alter their metabolism to meet the demands of migration. The storage of energy through the accumulation of fat and the control of sleep in nocturnal migrants require special physiological adaptations. In addition, the feathers of a bird suffer from wear-and-tear and require to be moulted. The timing of this moult – usually once a year but sometimes twice – varies with some species moulting prior to moving to their winter grounds and others molting prior to returning to their breeding grounds. Apart from physiological adaptations, migration sometimes requires behavioural changes such as flying in flocks to reduce the energy used in migration or the risk of predation.
Migration in birds is highly labile and is believed to have developed independently in many avian lineages. While it is agreed that the behavioral and physiological adaptations necessary for migration are under genetic control, some authors have argued that no genetic change is necessary for migratory behavior to develop in a sedentary species because the genetic framework for migratory behavior exists in nearly all avian lineages. This explains the rapid appearance of migratory behavior after the most recent glacial maximum.
Theoretical analyses show that detours that increase flight distance by up to 20% will often be adaptive on aerodynamic grounds – a bird that loads itself with food to cross a long barrier flies less efficiently. However, some species show circuitous migratory routes that reflect historical range expansions and are far from optimal in ecological terms. An example is the migration of continental populations of Swainson's thrushCatharus ustulatus, which fly far east across North America before turning south via Florida to reach northern South America; this route is believed to be the consequence of a range expansion that occurred about 10,000 years ago. Detours may also be caused by differential wind conditions, predation risk, or other factors.
Climate change
Large-scale climatic changes, as have been experienced in the past, are expected to have an effect on the timing of migration. Studies have shown a variety of effects including timing changes in migration, breeding as well as population variations.
Ecological effects
The migration of birds also aids the movement of other species, including those of ectoparasites such as ticks and lice, which in turn may carry micro-organisms including those of concern to human health. Due to the global spread of avian influenza, bird migration has been studied as a possible mechanism of disease transmission, but it has been found not to present a special risk; import of pet and domestic birds is a greater threat. Some viruses that are maintained in birds without lethal effects, such as the West Nile Virus may, however, be spread by migrating birds. Birds may also have a role in the dispersal of propagules of plants and plankton.
Some predators take advantage of the concentration of birds during migration. Greater noctule bats feed on nocturnal migrating passerines. Some birds of prey specialize on migrating waders.
Study techniques
Radars for monitoring bird migration. Kihnu, Estonia.
Early studies on the timing of migration began in 1749 in Finland, with Johannes Leche of Turku collecting the dates of arrivals of spring migrants.[
Bird migration routes have been studied by a variety of techniques including the oldest, marking. Swans have been marked with a nick on the beak since about 1560 in England. The scientific ringing was pioneered by Hans Christian Cornelius Mortensen in 1899. Other techniques include radar and satellite tracking. The rate of bird migration over the Alps (up to a height of 150 m) was found to be highly comparable between fixed-beam radar measurements and visual bird counts, highlighting the potential use of this technique as an objective way of quantifying bird migration.
Stable isotopes of hydrogen, oxygen, carbon, nitrogen, and sulfur can establish avian migratory connectivity between wintering sites and breeding grounds. Stable isotopic methods to establish migratory linkage rely on spatial isotopic differences in bird diet that are incorporated into inert tissues like feathers, or into growing tissues such as claws and muscle or blood.
An approach to identify migration intensity makes use of upward pointing microphones to record the nocturnal contact calls of flocks flying overhead. These are then analyzed in a laboratory to measure time, frequency and species.
An older technique developed by George Lowery and others to quantify migration involves observing the face of the full moon with a telescope and counting the silhouettes of flocks of birds as they fly at night.
Orientation behavior studies have been traditionally carried out using variants of a setup known as the Emlen funnel, which consists of a circular cage with the top covered by glass or wire-screen so that either the sky is visible or the setup is placed in a planetarium or with other controls on environmental cues. The orientation behavior of the bird inside the cage is studied quantitatively using the distribution of marks that the bird leaves on the walls of the cage. Other approaches used in pigeon homing studies make use of the direction in which the bird vanishes on the horizon.
Migration routes and countries with illegal hunting in Europe
Human activities have threatened many migratory bird species. The distances involved in bird migration mean that they often cross political boundaries of countries and conservation measures require international cooperation. Several international treaties have been signed to protect migratory species including the Migratory Bird Treaty Act of 1918 of the US. and the African-Eurasian Migratory Waterbird Agreement
The concentration of birds during migration can put species at risk. Some spectacular migrants have already gone extinct; during the passenger pigeon's (Ectopistes migratorius) migration the enormous flocks were a mile (1.6 km) wide, darkening the sky and 300 miles (480 km) long, taking several days to pass.
Other significant areas include stop-over sites between the wintering and breeding territories. A capture-recapture study of passerine migrants with high fidelity for breeding and wintering sites did not show similar strict association with stop-over sites.
Hunting along migration routes threatens some bird species. The populations of Siberian cranes (Leucogeranus leucogeranus) that wintered in India declined due to hunting along the route, particularly in Afghanistan and Central Asia. Birds were last seen in their favorite wintering grounds in Keoladeo National Park in 2002. Structures such as power lines, wind farms and offshore oil-rigs have also been known to affect migratory birds. Other migration hazards include pollution, storms, wildfires, and habitat destruction along migration routes, denying migrants food at stopover points. For example, in the East Asian–Australasian Flyway, up to 65% of key intertidal habitat at the Yellow Sea migration bottleneck has been destroyed since the 1950s
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Global Journal of Electronic and Communication Research (GJECR)
Global Journal of Electronic and Communication Research is a scholarly international journal that publishes original research papers in the fields of theory and design of circuits, systems, and devices for electronics, signal processing, and communication. Areas included (but not limited to) are signal and system theory, digital signal processing, network theory and circuit design, information theory, communication theory and techniques, modulation, source and channel coding, switching theory and techniques, communication protocols, optical communications, microwave theory and techniques, radar, sonar, antennas, wave propagation and more. Journal publishes research papers in the areas of both public communication systems (Telecommunication, mobile, Internet, and Cable TV) and private sys
International Journal of Advanced Computer Science and Technology
The International Journal of Advanced Computer Science and Technology (IJACST)is a peer-reviewed international journal. The purpose of this Journal is to provide an open forum to publish original high-quality research papers in the areas of computer science and technology, computer engineering, and computer systems to promote the exchange of research ideas, experiences and results. The areas covered by the journals are but not limited to the following: Computer Organizations and Architectures, Operating Systems, Software Systems, Digital Devices, Computer Components, and Interconnection Networks, Database Systems, Specification, Design, Prototyping, and Testing Methods and Tools, Neural Networks, Artificial Intelligence, Algorithms, Computational Science, E-commerce. Performance, Fault Tolerance, Reliability, Security, and Testability, Case Studies and Experimental and Theoretical Evaluations, Wireless Communications, New and Important Applications and Trends, Language and Search Engine Design, Pattern Recognition, Image Processing.It is an international scientific journal that aims to contribute to the constant scientific research and training, so as to promote computer science research in the field of computer science by publishing unique original research articles, innovative research, review articles, technical notes, and novel applications.
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Other animals may use similar drafting techniques when migrating. Lobsters, for example, migrate in close single-file formation "lobster trains", sometimes for hundreds of miles.
The Mediterranean and other seas present a major obstacle to soaring birds, which must cross at the narrowest points. Massive numbers of large raptors and storks pass through areas such as Gibraltar, Falsterbo, and the Bosphorus at migration times. More common species, such as the European honey buzzard, can be counted in hundreds of thousands in autumn. Other barriers, such as mountain ranges, can also cause funnelling, particularly of large diurnal migrants. This is a notable factor in the Central American migratory bottleneck. This concentration of birds during migration can put species at risk. Some spectacular migrants have already gone extinct, the most notable being the passenger pigeon. During migration the flocks were a mile (1.6 km) wide and 300 miles (500 km) long, taking several days to pass and containing up to a billion birds.
The term "shoal" can be used to describe any group of fish, including mixed-species groups, while "school" is used for more closely knit groups of the same species swimming in a highly synchronised and polarised manner.
Fish derive many benefits from shoaling behaviour including defence against predators (through better predator detection and by diluting the chance of capture), enhanced foraging success, and higher success in finding a mate. It is also likely that fish benefit from shoal membership through increased hydrodynamic efficiency...
Fish use many traits to choose shoalmates. Generally they prefer larger shoals, shoalmates of their own species, shoalmates similar in size and appearance to themselves, healthy fish, and kin (when recognised). The "oddity effect" posits that any shoal member that stands out in appearance will be preferentially targeted by predators. This may explain why fish prefer to shoal with individuals that resemble them. The oddity effect would thus tend to homogenise shoals...
One puzzling aspect of shoal selection is how a fish can choose to join a shoal of animals similar to themselves, given that it cannot know its own appearance. Experiments with zebrafish have shown that shoal preference is a learned ability, not innate. A zebrafish tends to associate with shoals that resemble shoals in which it was reared, a form of imprinting...
Other open questions of shoaling behaviour include identifying which individuals are responsible for the direction of shoal movement. In the case of migratory movement, most members of a shoal seem to know where they are going. In the case of foraging behaviour, captive shoals of golden shiner (a kind of minnow) are led by a small number of experienced individuals who knew when and where food was available.
Radakov estimated herring schools in the North Atlantic can occupy up to 4.8 cubic kilometres with fish densities between 0.5 and 1.0 fish/cubic metre. That's several billion fish in one school.
Between May and July huge numbers of sardines spawn in the cool waters of the Agulhas Bank and then follow a current of cold water northward along the east coast of South Africa. This great migration, called the sardine run, creates spectacular feeding frenzies along the coastline as marine predators, such as dolphins, sharks and gannets attack the schools
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