1.
Soil fertility
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In lands used for agriculture and other human activities, maintenance of soil fertility typically requires the use of soil conservation practices. This is because soil erosion and other forms of soil degradation generally result in a decline in quality with respect to one or more of the aspects indicated above, bioavailable phosphorus is the element in soil that is most often lacking. Nitrogen and potassium are also needed in substantial amounts, for this reason these three elements are always identified on a commercial fertilizer analysis. For example, a 10-10-15 fertilizer has 10 percent nitrogen,10 percent available phosphorus and 15 percent water-soluble potassium, sulfur is the fourth element that may be identified in a commercial analysis—e. g. 21-0-0-24 which would contain 21% nitrogen and 24% sulfate, inorganic fertilizers are generally less expensive and have higher concentrations of nutrients than organic fertilizers. However, some have criticized the use of fertilizers, claiming that the water-soluble nitrogen doesnt provide for the long-term needs of the plant. Slow-release fertilizers may reduce leaching loss of nutrients and may make the nutrients that they provide available over a period of time. Soil fertility is a process that involves the constant cycling of nutrients between organic and inorganic forms. As plant material and animal wastes are decomposed by micro-organisms, they release inorganic nutrients to the soil solution and those nutrients may then undergo further transformations which may be aided or enabled by soil micro-organisms. The balance between immobilization and mineralization processes depends on the balance and availability of nutrients and organic carbon to soil microorganisms. Natural processes such as lightning strikes may fix atmospheric nitrogen by converting it to, denitrification may occur under anaerobic conditions in the presence of denitrifying bacteria. Nutrient cations, including potassium and many micronutrients, are held in strong bonds with the negatively charged portions of the soil in a process known as cation exchange. In 2008 the cost of phosphorus as fertilizer more than doubled, recently the term peak phosphorus has been coined, due to the limited occurrence of rock phosphate in the world. Photosynthesis is the process whereby plants use light energy to chemical reactions which convert CO2 into sugars. As such, all plants require access to light and carbon dioxide to produce energy, grow and reproduce. While typically limited by nitrogen, phosphorus and potassium, low levels of carbon dioxide can act as a limiting factor on plant growth. Peer-reviewed and published studies have shown that increasing CO2 is highly effective at promoting plant growth up to levels over 300 ppm. Further increases in CO2 can, to a small degree
2.
Total fertility rate
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It is obtained by summing the single-year age-specific rates at a given time. The TFR is a rate, not based on the fertility of any real group of women since this would involve waiting until they had completed childbearing. Nor is it based on counting up the number of children actually born over their lifetime. Instead, the TFR is based on the fertility rates of women in their child-bearing years. When the NRR is exactly one, then each generation of women is exactly reproducing itself, the NRR is less widely used than the TFR, and the United Nations stopped reporting NRR data for member nations after 1998. But the NRR is particularly relevant where the number of babies born is very high due to gender imbalance. This is a significant factor in population, due to the high level of gender imbalance in the very populous nations of China. The gross reproduction rate, is the same as the NRR, in particular, the TFR does not necessarily predict how many children young women now will eventually have, as their fertility rates in years to come may change from those of older women now. However, the TFR is a summary of current fertility levels. In other words, the TPFR is a measure of life cycle fertility when childbearing age is changing. This is a significant factor in some countries, such as the Czech Republic, some measures seek to adjust for this timing effect to gain a better measure of life-cycle fertility. Replacement fertility is the fertility rate at which women give birth to enough babies to sustain population levels. If there were no mortality in the population until the end of the childbearing years then the replacement level of TFR would be very close to 2.0. The replacement fertility rate is roughly 2.0 births per woman for most industrialized countries, taken globally, the total fertility rate at replacement is 2.33 children per woman. At this rate, global population growth would tend towards zero, a log-transformation of the data gives an alternative view of the relation. The coefficients taken literally imply that for each 1% advance in GDP, the term lowest-low fertility is defined as TFR at or below 1.3. This is characteristic of some Eastern European, Southern European and East Asian countries, in 2001, more than half of the population of Europe lived in countries with lowest-low TFR, but the situation has since slightly improved. However, it may take several generations for a change in the fertility rate to be reflected in birth rate
3.
Nutrition
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Nutrition is the science that interprets the interaction of nutrients and other substances in food in relation to maintenance, growth, reproduction, health and disease of an organism. It includes food intake, absorption, assimilation, biosynthesis, catabolism, the diet of an organism is what it eats, which is largely determined by the availability, the processing and palatability of foods. A healthy diet includes preparation of food and storage methods that preserve nutrients from oxidation, heat or leaching, and they also provide preventive and therapeutic programs at work places, schools and similar institutions. Government regulation especially in terms of licensing, is less universal for the CCN than that of RD or RDN. Another advanced Nutrition Professional is a Certified Nutrition Specialist or CNS and these Board Certified Nutritionists typically specialize in obesity and chronic disease. In order to become certified, potential CNS candidate must pass an examination. This exam covers specific domains within the health sphere including, Clinical Intervention, a poor diet can cause the wasting of kwashiorkor in acute cases, and the stunting of marasmus in chronic cases of malnutrition. The first recorded dietary advice, carved into a Babylonian stone tablet in about 2500 BC, scurvy, later found to be a vitamin C deficiency, was first described in 1500 BC in the Ebers Papyrus. According to Walter Gratzer, the study of nutrition probably began during the 6th century BC, in China, the concept of Qi developed, a spirit or wind similar to what Western Europeans later called pneuma. Food was classified into hot and cold in China, India, Malaya, humours developed perhaps first in China alongside qi. Ho the Physician concluded that diseases are caused by deficiencies of elements, the first recorded nutritional experiment with human subjects is found in the Bibles Book of Daniel. Daniel and his friends were captured by the king of Babylon during an invasion of Israel, selected as court servants, they were to share in the kings fine foods and wine. But they objected, preferring vegetables and water in accordance with their Jewish dietary restrictions, the kings chief steward reluctantly agreed to a trial. Daniel and his friends received their diet for ten days and were compared to the kings men. Appearing healthier, they were allowed to continue with their diet, around 475 BC, Anaxagoras stated that food is absorbed by the human body and, therefore, contains homeomerics, suggesting the existence of nutrients. Around 400 BC, Hippocrates, who recognized and was concerned with obesity, the works that are still attributed to him, Corpus Hippocraticum, called for moderation and emphasized exercise. Salt, pepper and other spices were prescribed for various ailments in various preparations for example mixed with vinegar, in the 2nd century BC, Cato the Elder believed that cabbage could cure digestive diseases, ulcers, warts, and intoxication. Living about the turn of the millennium, Aulus Celsus, an ancient Roman doctor, believed in strong and weak foods
4.
Consanguinity
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Consanguinity is the property of being from the same kinship as another person. In that aspect, consanguinity is the quality of being descended from the same ancestor as another person, the laws of many jurisdictions set out degrees of consanguinity in relation to prohibited sexual relations and marriage parties. Rules of Consanguinity are also used to determine heirs of an estate according to statutes that govern intestate succession, the Knot System is a numerical notation that defines consanguinity. Issues of consanguinity arise in several aspects of the law, Laws prohibiting incest govern the degree of kinship within which marriage or sexual intercourse is permitted. These are almost universally prohibited within the degree of consanguinity. Some jurisdictions forbid marriage between first cousins, while others do not, marriage with aunts and uncles is legal in several countries. Consanguinity is also relevant to inheritance, particularly with regard to intestate succession, in general, the law favors inheritance by persons closely related to the deceased. Some jurisdictions bar citizens from service on a jury on the basis of consanguinity with persons involved in the case, in many countries, laws prohibiting nepotism bar employment of, or certain kinds of contracts with, the near relations of public officers or employees. Under Roman civil law, which early canon law of the Catholic Church followed, in the ninth century the church raised the number of prohibited degrees to seven and changed the method by which they were calculated. Eventually the nobility became too interrelated to marry as the pool of non-related prospective spouses became smaller and they had to either defy the churchs position or look elsewhere for eligible marriage candidates. In 1215 the Fourth Lateran Council made what they believed was a change to canon law reducing the number of prohibited degrees of consanguinity from seven back to four. The method of calculating prohibited degrees was changed also, instead of the former practice of counting up to the common ancestor then down to the proposed spouse, the new law computed consanguinity by counting back to the common ancestor. After 1215 the general rule was that while fourth cousins could marry without dispensation, in fourteenth century England, for example, papal dispensations for annulments due to consanguinity were relatively few. The connotations of degree of consanguinity varies by context, most cultures define a degree of consanguinity within which sexual interrelationships are regarded as incestuous. The rule is strict on the mothers side, where the limit is about four generations back. This rule does not apply to Muslims or other ethnic groups, islamThe category includes those one is forbidden to marry due to relationship of blood as well as some who are forbidden due to marital relations. And do not marry women whom your fathers married except what has already passed and it was indeed obscene, hateful and an evil way. And those already married except those whom your right hand possesses, and allowed for you are all besides these if you seek them with your property seeking chastity not fornication
5.
Culture
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Culture can be defined in numerous ways. In the words of anthropologist E. B, Tylor, it is that complex whole which includes knowledge, belief, art, morals, law, custom and any other capabilities and habits acquired by man as a member of society. The Cambridge English Dictionary states that culture is the way of life, especially the customs and beliefs. As a defining aspect of what it means to be human, culture is a concept in anthropology. The word is used in a sense as the evolved ability to categorize and represent experiences with symbols. The level of cultural sophistication has also sometimes seen to distinguish civilizations from less complex societies. Mass culture refers to the mass-produced and mass mediated forms of culture that emerged in the 20th century. When used as a count noun, a culture is the set of customs, traditions, in this sense, multiculturalism is a concept that values the peaceful coexistence and mutual respect between different cultures inhabiting the same planet. Sometimes culture is used to describe specific practices within a subgroup of a society. Samuel Pufendorf took over this metaphor in a context, meaning something similar. His use, and that of many writers after him, refers to all the ways in which human beings overcome their original barbarism, and through artifice, become fully human. To be cultural, to have a culture, is to inhabit a place sufficiently intensive to cultivate it—to be responsible for it, to respond to it, thus a contrast between culture and civilization is usually implied in these authors, even when not expressed as such. Cultural invention has come to any innovation that is new and found to be useful to a group of people and expressed in their behavior. Humanity is in a global accelerating culture change period, driven by the expansion of commerce, the mass media, and above all. Culture repositioning means the reconstruction of the concept of a society. Cultures are internally affected by both forces encouraging change and forces resisting change, Social conflict and the development of technologies can produce changes within a society by altering social dynamics and promoting new cultural models, and spurring or enabling generative action. These social shifts may accompany ideological shifts and other types of cultural change, for example, the U. S. feminist movement involved new practices that produced a shift in gender relations, altering both gender and economic structures. Environmental conditions may also enter as factors, Cultures are externally affected via contact between societies, which may also produce—or inhibit—social shifts and changes in cultural practices
6.
Instinct
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Instinct or innate behavior is the inherent inclination of a living organism towards a particular complex behavior. Any behavior is if it is performed without being based upon prior experience. Sea turtles, newly hatched on a beach, will move toward the ocean. A kangaroo climbs into its mothers pouch upon being born, honeybees communicate by dancing in the direction of a food source without formal instruction. Other examples include animal fighting, animal behavior, internal escape functions. The absence of volitional capacity must not be confused with an inability to modify fixed action patterns, the role of instincts in determining the behavior of animals varies from species to species. The more complex the system of an animal, the greater is the role of the cerebral cortex and social learning. A comparison between a crocodile and an elephant illustrates how mammals for example are heavily dependent on social learning, lionesses and chimpanzees raised in zoos away from their birth mothers most often reject their own offspring because they have not been taught the skills of mothering. Such is not the case with species such as reptiles. In everyday speech, the instinct is often used to refer to intuition or even clairvoyance. Jean Henri Fabre, an entomologist, considered instinct to be any behavior which did not require cognition or consciousness to perform, Fabres inspiration was his intense study of insects, some of whose behaviors he wrongly considered fixed and not subject to environmental influence. Instinct as a concept fell out of favor in the 1920s with the rise of behaviorism and such thinkers as B. F. Skinner, which held that most significant behavior is learned. These beliefs, like Fabres belief that most behaviors were simply reflexive, an interest in innate behaviors arose again in the 1950s with Konrad Lorenz and Nikolaas Tinbergen, who made the distinction between instinct and learned behaviors. Our modern understanding of behavior in animals owes much to their work. For instance, there exists a sensitive period for a bird in which it learns the identity of its mother, Konrad Lorenz famously had a goose imprint on his boots. Thereafter the goose would follow whoever wore the boots, the identity of the gooses mother was learned, but the gooses behavior towards the boots was instinctive. The term instinct in psychology was first used in the 1870s by Wilhelm Wundt, by the close of the 19th century, most repeated behavior was considered instinctual. In a survey of the literature at that time, one researcher chronicled 4,000 human instincts, as research became more rigorous and terms better defined, instinct as an explanation for human behavior became less common
7.
Endocrinology
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Endocrinology is a branch of biology and medicine dealing with the endocrine system, its diseases, and its specific secretions known as hormones. Specializations include behavioral endocrinology and comparative endocrinology, the endocrine system consists of several glands, all in different parts of the body, that secrete hormones directly into the blood rather than into a duct system. Endocrinology is the study of the system in the human body. This is a system of glands which secrete hormones, hormones are chemicals which affect the actions of different organ systems in the body. Examples include thyroid hormone, growth hormone, and insulin, the endocrine system involves a number of feedback mechanisms, so that often one hormone will control the action or release of another secondary hormone. If there is too much of the hormone, it may provide negative feedback to the primary hormone. This definition holds for most classical hormones, but there are also paracrine mechanisms, autocrine signals, a neuroendocrine signal is a classical hormone that is released into the blood by a neurosecretory neuron. Peptide hormones and protein hormones consist of three to more than 200 amino acid residues and can have a mass as large as 30,000 grams per mole. All hormones secreted by the pituitary gland are peptide hormones, as are leptin from adipocytes, ghrelin from the stomach, steroid hormones are converted from their parent compound, cholesterol. Mammalian steroid hormones can be grouped into five groups by the receptors to which they bind, glucocorticoids, mineralocorticoids, androgens, estrogens, and progestogens. Some forms of vitamin D, such as calcitriol, are steroid-like and bind to homologous receptors and these organs include the pituitary, thyroid, adrenals, ovaries, testes, and pancreas. An endocrinologist is a physician who specializes in treating disorders of the system, such as diabetes, hyperthyroidism. The diagnosis and treatment of diseases are guided by laboratory tests to a greater extent than for most specialties. Many diseases are investigated through excitation/stimulation or inhibition/suppression testing and this might involve injection with a stimulating agent to test the function of an endocrine organ. Blood is then sampled to assess the changes of the relevant hormones or metabolites, an endocrinologist needs extensive knowledge of clinical chemistry and biochemistry to understand the uses and limitations of the investigations. A second important aspect of the practice of endocrinology is distinguishing human variation from disease, atypical patterns of physical development and abnormal test results must be assessed as indicative of disease or not. Diagnostic imaging of endocrine organs may reveal incidental findings called incidentalomas, Endocrinology involves caring for the person as well as the disease. Most endocrine disorders are diseases that need lifelong care
8.
Economics
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Economics is a social science concerned chiefly with description and analysis of the production, distribution, and consumption of goods and services according to the Merriam-Webster Dictionary. Economics focuses on the behaviour and interactions of economic agents and how economies work, consistent with this focus, textbooks often distinguish between microeconomics and macroeconomics. Microeconomics examines the behaviour of elements in the economy, including individual agents and markets, their interactions. Individual agents may include, for example, households, firms, buyers, macroeconomics analyzes the entire economy and issues affecting it, including unemployment of resources, inflation, economic growth, and the public policies that address these issues. Economic analysis can be applied throughout society, as in business, finance, health care, Economic analyses may also be applied to such diverse subjects as crime, education, the family, law, politics, religion, social institutions, war, science, and the environment. At the turn of the 21st century, the domain of economics in the social sciences has been described as economic imperialism. The ultimate goal of economics is to improve the conditions of people in their everyday life. There are a variety of definitions of economics. Some of the differences may reflect evolving views of the subject or different views among economists, to supply the state or commonwealth with a revenue for the publick services. Say, distinguishing the subject from its uses, defines it as the science of production, distribution. On the satirical side, Thomas Carlyle coined the dismal science as an epithet for classical economics, in this context and it enquires how he gets his income and how he uses it. Thus, it is on the one side, the study of wealth and on the other and more important side, a part of the study of man. He affirmed that previous economists have usually centred their studies on the analysis of wealth, how wealth is created, distributed, and consumed, but he said that economics can be used to study other things, such as war, that are outside its usual focus. This is because war has as the goal winning it, generates both cost and benefits, and, resources are used to attain the goal. If the war is not winnable or if the costs outweigh the benefits. Some subsequent comments criticized the definition as overly broad in failing to limit its subject matter to analysis of markets, there are other criticisms as well, such as in scarcity not accounting for the macroeconomics of high unemployment. The same source reviews a range of included in principles of economics textbooks. Among economists more generally, it argues that a particular definition presented may reflect the direction toward which the author believes economics is evolving, microeconomics examines how entities, forming a market structure, interact within a market to create a market system
9.
Emotion
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Emotion, generally speaking, is any relatively brief conscious experience characterized by intense mental activity and a high degree of pleasure or displeasure. Scientific discourse has drifted to other meanings and there is no consensus on a definition, Emotion is often intertwined with mood, temperament, personality, disposition, and motivation. In some theories, cognition is an important aspect of emotion and those acting primarily on the emotions they are feeling may seem as if they are not thinking, but mental processes are still essential, particularly in the interpretation of events. For example, the realization of our believing that we are in a dangerous situation, other theories, however, claim that emotion is separate from and can precede cognition. According to some theories, they are states of feeling that result in physical and psychological changes that influence our behavior, the physiology of emotion is closely linked to arousal of the nervous system with various states and strengths of arousal relating, apparently, to particular emotions. Emotion is also linked to behavioral tendency, extroverted people are more likely to be social and express their emotions, while introverted people are more likely to be more socially withdrawn and conceal their emotions. Emotion is often the force behind motivation, positive or negative. Nor is the emotion an entity that causes these components, Emotions involve different components, such as subjective experience, cognitive processes, expressive behavior, psychophysiological changes, and instrumental behavior. More recently, emotion is said to consist of all the components, the different components of emotion are categorized somewhat differently depending on the academic discipline. In psychology and philosophy, emotion typically includes a subjective, conscious experience characterized primarily by psychophysiological expressions, biological reactions, a similar multicomponential description of emotion is found in sociology. For example, Peggy Thoits described emotions as involving physiological components, cultural or emotional labels, expressive body actions, the numerous theories that attempt to explain the origin, neurobiology, experience, and function of emotions have only fostered more intense research on this topic. Current areas of research in the concept of emotion include the development of materials that stimulate, in addition PET scans and fMRI scans help study the affective processes in the brain. Emotions can be defined as a positive or negative experience that is associated with a pattern of physiological activity. Emotions produce different physiological, behavioral and cognitive changes, the original role of emotions was to motivate adaptive behaviors that in the past would have contributed to the survival of humans. Emotions are responses to significant internal and external events, the word emotion dates back to 1579, when it was adapted from the French word émouvoir, which means to stir up. The term emotion was introduced into academic discussion to replace passion, according to one dictionary, the earliest precursors of the word likely dates back to the very origins of language. The modern word emotion is heterogeneous In some uses of the word, on the other hand, emotion can be used to refer to states that are mild and to states that are not directed at anything. One line of research looks at the meaning of the word emotion in everyday language
10.
Infant mortality
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Infant mortality refers to deaths of young children, typically those less than one year of age. It is measured by the infant mortality rate, which is the number of deaths of children one year of age per 1000 live births. The Under-Five Mortality Rate is also an important statistic considering the Infant Mortality Rate has a limit on focusing on children only under one year of age. Premature birth is the biggest contributor to the IMR, one of the most common preventable causes of infant mortality is smoking during pregnancy. Many factors contribute to infant mortality, such as the level of education, environmental conditions. Improving sanitation, access to drinking water, immunization against infectious diseases. Child mortality is the death of a child before the fifth birthday. National statistics sometimes group these two mortality rates together, Infant mortality rate was an indicator used to monitor progress towards the Fourth Goal of the Millennium Development Goals of the United Nations for the year 2015. It is now a target in the Sustainable Development Goals for Goal Number 3, throughout the world, Infant Mortality Rate fluctuates drastically, and according to Biotechnology and Health Sciences, education and life expectancy in the country is the leading indicator of IMR. This study was conducted across 135 countries over the course of 11 years with Africa having the highest Infant Mortality Rate of any other region studied with 68 deaths per 1,000 live births. Infant mortality rate is the number of deaths per 1,000 live births of children one year of age. The rate for a region is the number of children dying under one year of age, divided by the number of live births during the year. Forms of infant mortality, Perinatal mortality is late fetal death, Neonatal mortality is newborn death occurring within 28 days postpartum. Neonatal death is attributed to inadequate access to basic medical care, during pregnancy. This accounts for 40–60% of infant mortality in developing countries, postneonatal mortality is the death of children aged 29 days to one year. The major contributors to postneonatal death are malnutrition, infectious disease, troubled pregnancy, Sudden Infant Death Syndrome, causes of infant mortality directly lead to the death. Greatest percentage reduction of infant mortality occurs in countries already have low rates of infant mortality. Common causes are preventable with low-cost measures, in the United States, a primary determinant of infant mortality risk is infant birth weight with lower birth weights increasing the risk of infant mortality
11.
Religiosity
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Religiosity, in its broadest sense, is a comprehensive term used to refer to the numerous aspects of religious activity, dedication, and belief. Another term less often used is religiousness, in its narrowest sense, religiosity deals more with how religious a person is, and less with how a person is religious. Decades of anthropological, sociological, and psychological research have established that religious congruence is actually rare, people’s religious ideas, are fragmented, loosely connected, and context dependent, like in all other domains of culture and in life. The beliefs, affiliations, and behaviors of any individual are complex activities that have many sources including culture, as examples of religious incongruence he notes, Observant Jews may not believe what they say in their Sabbath prayers. Christian ministers may not believe in God, and people who regularly dance for rain don’t do it in the dry season. Demographic studies often show wide diversity of beliefs, belonging. Global studies on religion also show diversity, numerous studies have explored the different components of human religiosity. What most have found is there are multiple dimensions. What most measures of religiosity find is that there is at least some distinction between religious doctrine, religious practice, and spirituality, for example, one can accept the truthfulness of the Bible, but never attend a church or even belong to an organized religion. Another example is an individual who does not hold orthodox Christian doctrines and these are explanatory examples of the broadest dimensions of religiosity and that they may not be reflected in specific religiosity measures. Most dimensions of religiosity are correlated, meaning people who attend church services are also likely to score highly on the belief. But individuals do not have to high on all dimensions or low on all dimensions. Sociologists have differed over the number of components of religiosity. Charles Glocks five-dimensional approach was among the first of its kind in the field of sociology of religion, other sociologists adapted Glocks list to include additional components. The contributions of genes and environment to religiosity have been quantified in studies of twins and sociological studies of welfare, availability, a market-based theory of religious choice and governmental regulation of religion have been the dominant theories used to explain variations of religiosity between societies. However, Gill and Lundsgaarde documented a much stronger correlation between welfare state spending and religiosity, see Welfare spending vs Church attendance diagram on the right. A meta-analysis found a correlation of -.24 between intelligence quotient and religiosity for western societies. The correlation was suggested to be a result of nonconformity, more cognitive and less intuitive thinking styles among the less religious, the study noted limitations on the results such as not considering of the role of religion type and of culture in assessing the relationship
12.
Income and fertility
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Income and fertility is the association between monetary gain on one hand, and the tendency to produce offspring on the other. There is generally an inverse correlation between income and fertility within and between nations, the higher the degree of education and GDP per capita of a human population, subpopulation or social stratum, the fewer children are born in any industrialized country. In a 1974 UN population conference in Bucharest, Karan Singh, roughly speaking, nations or subpopulations with higher GDP per capita are observed to have fewer children, even though a richer population can support more children. Malthus held that in order to prevent widespread suffering, from famine for example, the demographic-economic paradox suggests that reproductive restraint arises naturally as a consequence of economic progress. Although the relationship might also work the way around, because a lower fertility leads to more resources that are available per child. The increase in GDP in Eastern Europe after 1990 has been correlated with childbearing postponement, when looking at an individual level in advanced countries where birth control is the norm, increased income is likewise associated with decreased fertility. A reduction in fertility can lead to a population which leads to a variety of problems. A related concern is that birth rates tend to place a greater burden of child rearing. Consequently, inequality lowers average education and hampers economic growth, also, in countries with a high burden of this kind, a reduction in fertility can hamper economic growth as well as the other way around. A United Nations report in 2002 came to the conclusion that sharp declines in fertility rates in India, Nigeria, increased unemployment is generally associated with lower fertility. Some scholars have questioned the assumption that economic development and fertility are correlated in a simple negative manner. Pointed out that “unprecedented increases” in social and economic development in the 20th century had been accompanied by considerable declines in growth rates. This negative association between human fertility and socio-economic development has been “one of the most solidly established and generally accepted empirical regularities in the social sciences”, the researchers used cross-sectional and longitudinal analyses to examine the relationship between total fertility rate and the human development index. The main finding of the study was that, in developed countries with HDI above 0.9. This means that the previously negative development-fertility association is reversed, the graph becomes J-shaped, some researchers doubt J-shaped relationship fertility and socio-economic development. For example, Fumitaka Furuoka employed a piecewise regression analysis to examine the relationship between total fertility rate and human development index, however, he found no empirical evidence to support the proposition that advances in development are able to reverse declining fertility rates. More precisely, the findings of Furuoka’s 2009 study indicate that in countries with a low human development index. Likewise, in countries with a human development index, higher levels of HDI are associated with lower fertility rates
13.
Women in the workforce
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Until modern times, legal and cultural practices, combined with the inertia of longstanding religious and educational conventions, restricted womens entry and participation in the workforce. Womens lack of access to education had effectively excluded them from the practice of well-paid. Women were largely limited to low-paid and poor status occupations for most of the 19th and 20th centuries, or earned less pay than men for doing the same work. Women are viewed as the caregiver to children still to this day. The increasing rates of women contributing in the force has led to a more equal disbursement of hours worked across the regions of the world. However, in western European countries the nature of womens employment participation remains markedly different from that of men, for example, few women are in continuous full-time employment after the birth of a first child. Due to the lack of childcare and because women in Britain lose 9% of their wage after their first child and 16% after their second child. In the United States, womens earnings were 83 percent of male full-time workers in 2014. ”With the current norm in place, women are forced to juggle full-time jobs. As the Civil War raged in the U. S, much of her site visits were conducted in Philadelphia, New York and Boston. She distilled her research to list over 500 jobs that were open to women as well as the information about the jobs and she also indicated when employers offered their reasons for wage differentials based on gender. She dedicated her book to worthy and industrious women in the United States, striving to earn a livelihood, and the book garnered much attention by reviewers and scholars across the country. She sold her rights to the book to another publisher who put it out instead as an encyclopedia, The Employments of Women, A Cyclopaedia of Womans Work and it sold better once it was re-titled again in 1870 as How Women Can Make Money, Married or Single. In total, the different versions of the book ended up with 36 editions published between 1862 and 2006, and six editions of the adaptation in German. In the twentieth century, division of labor by gender has been studied most systematically in womens studies, occupational studies, such as the history of medicine or studies of professionalization, also examine questions of gender, and the roles of women in the history of particular fields. Women dominate as accountants, auditors, and psychologists and this body of law is called employment discrimination law, and gender and race discrimination are the largest sub-sections within the area. Laws specifically aimed at preventing discrimination against women have been passed in countries, see. Women still contribute to their communities in many regions mainly through agricultural work, in Southern Asia, Western Asia, and Africa, only 20% of women work at paid non-agricultural jobs. Worldwide, womens rate of employment outside of agriculture grew to 41% by 2008
14.
Fertility and intelligence
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The combined net effect of these two forces on ultimate population intelligence is not well studied and is unclear. Other correlates of IQ include income and educational attainment, which are also fertility factors that are correlated with fertility rate. These men, taken as a whole, had few children, in 1963, Weyl and Possony asserted that comparatively small differences in average intelligence can become very large differences in the very high I. Q. ranges. A decline in average intelligence of only a few points will mean a much smaller population of gifted individuals. More rigorous studies carried out on Americans alive after the Second World War returned different results suggesting a positive correlation with respect to intelligence. Will probably continue in the future in the United States. Other researchers began to report a negative correlation in the 1960s after two decades of neutral or positive fertility. In 1982, Daniel Vining sought to address issues in a large study on the fertility of over 10,000 individuals throughout the United States. The average fertility in his study was correlated at −0.86 with IQ for white women and −0.96 for black women. Vining argued that this indicated a drop in the genotypic average IQ of 1.6 points per generation for the white population, if children had, on average, the same IQ as their parents, IQ would decline by.81 points per generation. Taking.71 for the heritability of IQ as given by Jinks and Fulker. The Bell Curve argued that the average genotypic IQ of the United States was declining due to both dysgenetic fertility and large scale immigration of groups with low average IQ. In a 1999 study Lynn examined the relationship between the intelligence of adults aged 40 and above and their numbers of children and their siblings, data was collected from the 1994 National Opinion Research Center survey among a representative sample of 2992 English-speaking individuals aged 18 years. Findings revealed that weak negative correlations of −0.05 and −0.09, further analysis showed that the negative correlation was present only in females. In 2004 Richard Lynn and Marian Van Court attempted a straightforward replication of Vinings work and their study returned similar results, with the genotypic decline measuring at 0.9 IQ points per generation for the total sample and 0.75 IQ points for whites only. Without migration the average IQ of the US population will decline by about 0.8 points per generation, Lynn and Harvey found a correlation of −0.73 between national IQ and fertility. They estimated that the effect had been a decline in the worlds genotypic IQ of 0.86 IQ points for the years 1950–2000, a further decline of 1.28 IQ points in the worlds genotypic IQ is projected for the years 2000–2050. They thought it probable that both genotypic and phenotypic IQ will gradually start to decline for the whole world, there is thus an inverse correlation between income and fertility within and between nations
15.
Age and female fertility
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Female fertility is affected by age. Age is thus a major fertility factor for women, after puberty, female fertility increases and then decreases, with advanced maternal age causing an increased risk of female infertility. In humans, a womans fertility peaks in the early and mid-20s, while many sources suggest a more dramatic drop at around 35, this is unclear since studies are still cited from the nineteenth century. One 2004 study of European women found fertility of the 27-34, at age 45, a woman starting to try to conceive will have no live birth in 50–80 percent of cases. Menopause, or the cessation of periods, generally occurs in the 40s and 50s and marks the cessation of fertility. A womans fertility peaks in her early and mid-20s after which it starts to decline, however, the exact estimates of the chances of a woman to conceive after a certain age are not clear, and are subject to debate. For women aged 38, however, only 77 out of every 100 will do so, the women were divided into four age groups, 19–26, 27–29, 30–34 and 35–39. Statistical analysis showed that the women in the 27–29 age group had significantly less chance on average of becoming pregnant than did the 19- to 26-year-olds. Pregnancy rates did not change notably between the 27–29 age group and the 30–34 age group, but dropped significantly for the 35–39 age group. The age of the partner had a significant impact on female fertility among the women who had reached their mid-30s. However, experts said the new study was too small and there were too many variables which were too difficult to sort out, david Dunson, a biostatistician at the U. S. A French study found no difference between the fertility rate of women under 25 and those ages 26–30, after which fertility started to decrease, estimating the fertility of a woman is quite difficult because of the male factor. This French study looked at 2,193 women who were using artificial insemination because their husbands were azoospermic. The cumulative success rates after 12 cycles of insemination were 73% for women under age 25, 74% in women ages 26–30, 61% for ages 31–35, and 54% in the over 35 age group. The below is a table containing estimates of the percentage of women who, if starting to conceive at a certain age, note that while for the young ages researchers tend to agree, for older ages there is discrepancy. In terms of ovarian reserve, a woman has 12% of her reserve at age 30 and has only 3% at age 40. 81% of variation in ovarian reserve is due to age alone, transvaginal ultrasound can also be used to “count the number of follicles” and this procedure is called Antral Follicle Count. A study of a population of French women from 1670 and 1789 shows that those who married at age 20–24 had 7.0 children on average and 3. 7% remained childless
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Paternal age effect
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The paternal age effect is the statistical relationship between paternal age at conception and biological effects on the child. Such effects can relate to birthweight, congenital disorders, life expectancy, a 2017 review found that while severe health effects are associated with higher paternal age, the total increase in problems caused by paternal age is low. While paternal age has increased since 1960-1970 this is not seen as a public health concern. The genetic quality of sperm, as well as its volume and motility, all may decrease with age, crow to claim that the greatest mutational health hazard to the human genome is fertile older males. The paternal age effect was first proposed implicitly by Weinberg in 1912, dNA-based research started more recently, in 1998, in the context of paternity testing. Evidence for a paternal age effect has been proposed for a number of conditions, diseases, in many of these, the statistical evidence of association is weak, and the association may be related by confounding factors, or behavioural differences. These conditions are Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, achondroplasia, thanatophoric dysplasia, multiple endocrine neoplasia type 2, and multiple endocrine neoplasia type 2b. The most significant effect concerns achondroplasia, which occur in about 1 in 1,875 children fathered by men over 50. However, the risk for achondroplasia is still considered clinically negligible, several studies have reported that advanced paternal age is associated with an increased risk of miscarriage. The strength of the association differs between studies and it has been suggested that these miscarriages are caused by chromosome abnormalities in the sperm of aging men. An increased risk for stillbirth has also suggested for pregnancies fathered by men over 45. A systematic review published in 2010 concluded the risk of low birthweight in infants with paternal age is saucer-shaped, that is, the highest risks occur at low and at high paternal ages. Compared with an age of 25–28 years as a reference group. There was no association of paternal age with preterm births or with small for gestational age births, Schizophrenia is thought by some to be associated with advanced paternal age but it is not proven. Some studies examining autism spectrum disorder and advanced age have demonstrated an association between the two, although there also appears to be an increase with maternal age. There is no relationship with maternal age. The mechanisms under discussion are not mutually exclusive, paternal age may be associated with an increased risk of breast cancer, but the association is weak and there are confounding effects. According to a 2017 review, there is consistent evidence of an increase in incidence of acute lymphoblastic leukemia with paternal age
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Fertilisation
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The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation. In 1784, Spallanzani established the need of interaction between the females ovum and males sperm to form a zygote, oscar Hertwig, in Germany, described the fusion of nuclei of spermatozoa and of ova from sea urchin. In flowering plants there are two sperm from each pollen grain, in seed plants, after pollination, a pollen grain germinates, and a pollen tube grows and penetrates the ovule through a tiny pore called a micropyle. The sperm are transferred from the pollen through the pollen tube, bryophyte is a traditional name used to refer to all embryophytes that do not have true vascular tissue and are therefore called non-vascular plants. Some bryophytes do have specialised tissues for the transport of water, however, since these do not contain lignin, a fern is a member of a group of roughly 12,000 species of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular and they have stems and leaves, like other vascular plants. Most ferns have what are called fiddleheads that expand into fronds, the gymnosperms are a group of seed-producing plants that includes conifers, Cycads, Ginkgo, and Gnetales. The term gymnosperm comes from the Greek composite word γυμνόσπερμος, meaning naked seeds and their naked condition stands in contrast to the seeds and ovules of flowering plants, which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, often modified to form cones, the pollen tube does not directly reach the ovary in a straight line. It travels near the skin of the style and curls to the bottom of the ovary, then near the receptacle, it breaks through the ovule through the micropyle, after being fertilised, the ovary starts to swell and develop into the fruit. With multi-seeded fruits, multiple grains of pollen are necessary for syngamy with each ovule, the growth of the pollen tube is controlled by the vegetative cytoplasm. The sperms are interconnected and dimorphic, the one, in a number of plants, is also linked to the tube nucleus and the interconnected sperm. Double fertilisation is the process in angiosperms in which two sperm from each pollen tube fertilise two cells in a gametophyte that is inside an ovule. After the pollen tube enters the gametophyte, the tube nucleus disintegrates. This is the point when fertilisation actually occurs, pollination and fertilisation are two separate processes, the nucleus of the other sperm cell fuses with two haploid polar nuclei in the centre of the gametophyte. This triploid cell divides through mitosis and forms the endosperm, a nutrient-rich tissue, the two central-cell maternal nuclei that contribute to the endosperm arise by mitosis from the single meiotic product that also gave rise to the egg. Therefore, maternal contribution to the constitution of the triploid endosperm is double that of the embryo
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Athlete
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An athlete or sportsman is a person who is good at a sport and competes in one or more sports that involve physical strength, speed or endurance. The terms application to those who participate in activities, such as horse riding or driving, is somewhat controversial. Athletes may be professionals or amateurs, most professional athletes have particularly well-developed physiques obtained by extensive physical training and strict exercise accompanied by a strict dietary regimen. The word athlete is a romanization of the Greek, άθλητὴς, athlētēs, one who participates in a contest, from ἄθλος, áthlos, or ἄθλον, áthlon, athletes involved in isotonic exercises have an increased mean left ventricular end-diastolic volume and are less likely to be depressed. Due to their strenuous physical activities, athletes are far more likely than the population to visit massage salons and pay for services from massage therapists. An all-around athlete is a person who competes in sports at a high level. Examples of people who played numerous sports professionally include Jim Thorpe, Lionel Conacher, Deion Sanders, Danny Ainge and Babe Zaharias. Others include Ricky Williams, Bo Jackson, and Damon Allen, japanese athletes such as Kazushi Sakuraba, Kazuyuki Fujita, Masakatsu Funaki and Naoya Ogawa have successfully competed in both professional wrestling and mixed martial arts. The title of Worlds Greatest Athlete traditionally belongs to the worlds top competitor in the decathlon and heptathlon in track and field. The decathlon consists of 10 events,100 meters, long jump, shot put, high jump,400 meters,110 m hurdles, discus, pole vault, javelin, and 1500 m. The heptathlon consists of seven events, the 100 m hurdles, high jump, shot put,200 meters, long jump, javelin, and 800 meters. These competitions require an athlete to possess the whole spectrum of ability in order to be successful including speed, strength, coordination, jumping ability. Although the title Worlds Greatest Athlete seems a natural fit for these two events, its association with the decathlon/heptathlon officially began with Jim Thorpe. During the 1912 Olympics in Stockholm, Sweden, Thorpe won the medal in the Decathlon. Thorpe notably also competed professionally in soccer, baseball, American Football, and basketball, and competed collegiately in track and field, soccer, baseball, lacrosse, and did ballroom dancing. King Gustav V of Sweden, while awarding Thorpe the decathlon gold said, You and that title has become associated with the decathlon event ever since. Outdoor enthusiast Jock Athlete of the Year Suresh Joachim Multiple Guinness World Record holder
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Breastfeeding
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Breastfeeding, also known as nursing, is the feeding of babies and young children with milk from a womans breast. Health professionals recommend that breastfeeding begin within the first hour of a life and continue as often. During the first few weeks of life babies may nurse roughly every two to three hours, the duration of a feeding is usually ten to fifteen minutes on each breast. Mothers may pump milk so that it can be used later when breastfeeding is not possible, Breastfeeding has a number of benefits to both mother and baby, which infant formula lacks. Deaths of an estimated 820,000 children under the age of five could be prevented every year with increased breastfeeding. Breastfeeding decreases the risk of respiratory infections and diarrhea, both in developing and developed countries. Other benefits include lower risks of asthma, food allergies, celiac disease, type 1 diabetes, Breastfeeding may also improve cognitive development and decrease the risk of obesity in adulthood. Mothers may feel pressure to breastfeed, however in the developed world children generally grow up normally when bottle fed, benefits for the mother include less blood loss following delivery, better uterus shrinkage, weight loss, and less postpartum depression. Breastfeeding delays the return of menstruation and fertility, a known as lactational amenorrhea. Long term benefits for the mother include decreased risk of breast cancer, cardiovascular disease, Breastfeeding is less expensive than infant formula. Health organizations, including the World Health Organization, recommend breastfeeding exclusively for six months and this means that no other foods or drinks other than possibly vitamin D are typically given. After the introduction of foods at six months of age, recommendations include continued breastfeeding until at least one to two years of age, globally about 38% of infants are only breastfed during their first six months of life. In the United States, about 75% of women begin breastfeeding, Medical conditions that do not allow breastfeeding are rare. Mothers who take certain drugs and medications should not breastfeed. Smoking, limited intake of alcohol, and coffee are not reasons to avoid breastfeeding, the endocrine system drives milk production during pregnancy and the first few days after the birth. From the twenty-fourth week of pregnancy, a body produces hormones that stimulate the growth of the breasts milk duct system. After birth, the hormone oxytocin contracts the muscle layer of cells surrounding the alveoli to squeeze milk into the duct system. Oxytocin is also necessary for the milk ejection reflex, or let-down to occur, let-down occurs in response to the babys suckling, though it also may be a conditioned response, e. g. to the cry of the baby
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The pill
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The combined oral contraceptive pill, often referred to as the birth control pill or colloquially as the pill, is a birth control method that includes a combination of an estrogen and a progestogen. When taken by every day, these pills inhibit female fertility. They were first approved for use in the United States in 1960. They are currently used by more than 100 million women worldwide, as of 2012, 16% of U. S. women aged 15-44 reported being on the birth control pill, making it the most widely used contraceptive method among women of that age range. Use varies widely by country, age, education, and marital status, one third of women aged 16–49 in the United Kingdom currently use either the combined pill or progestogen-only pill, compared with only 1% of women in Japan. Two forms are on the World Health Organizations List of Essential Medicines, the pill was a catalyst for the sexual revolution. Combined oral contraceptive pills should be taken at the time each day. If one or more tablets are forgotten for more than 12 hours, most brands of combined pills are packaged in one of two different packet sizes, with days marked off for a 28-day cycle. For the 21-pill packet, a pill is consumed daily for three weeks, followed by a week of no pills, for the 28-pill packet,21 pills are taken, followed by a week of placebo or sugar pills. A woman on the pill will have a withdrawal bleed sometime during the placebo week, there are also two newer combination birth control pills that have 24 days of active hormone pills, followed by 4 days of placebo. The placebo pills allow the user to take a pill every day, placebo pills may contain an iron supplement, as iron requirements increase during menstruation. Failure to take pills during the placebo week does not impact the effectiveness of the pill, the withdrawal bleeding that occurs during the break from active pills was thought to be reassuring, as a physical confirmation of not being pregnant. The 28-day pill package also simulates the average menstrual cycle, though the events during a pill cycle are significantly different from those of a normal ovulatory menstrual cycle. The pill suppresses the normal cycle, and the withdrawal bleeding occurs while the pills are taken. The withdrawal bleeding is also predictable, unexpected breakthrough bleeding can be a possible side effect of longer term active regimens. Attempting this with bi- or tri-phasic pill formulations carries a risk of breakthrough bleeding. It will not, however, increase the risk of getting pregnant, starting in 2003, women have also been able to use a three-month version of the Pill. Seasonique is another version in which the week every three months is replaced with a week of low-dose estrogen
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Intrauterine device
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An intrauterine device is a small, often T-shaped birth control device that is inserted into a womans uterus to prevent pregnancy. IUDs are one form of long-acting reversible birth control, among birth control methods, IUDs, along with contraceptive implants, result in the greatest satisfaction among users. Evidence supports effectiveness and safety in adolescents and those who have and have not previously had children, once removed, even after long-term use, fertility returns to normal rapidly. Failure rates are about 0. 8% with copper devices and 0. 2% with hormonal devices in the first year of use, while copper IUDs may increase menstrual bleeding and result in more painful cramps, hormonal IUDs may reduce menstrual bleeding or stop menstruation altogether. Cramping can be treated with NSAIDs, other potential complications include expulsion and rarely perforation of the uterus. IUDs do not affect breastfeeding and can be inserted immediately after delivery and they may also be used immediately after an abortion. The use of IUDs as a form of birth control dates from the 1800s, the types of intrauterine devices available, and the names they go by, differ by location. In the United States, there are two available, Nonhormonal copper IUD IUD with progestogen The WHO ATC labels both copper and hormonal devices as IUDs. In the United Kingdom, there are over 10 different types of copper IUDs available, in the UK, the term IUD refers only to these copper devices. Hormonal intrauterine contraception is considered to be a different type of control and is labeled with the term intrauterine system. Copper IUDs primarily work by disrupting sperm motility and damaging sperm so that they are prevented from joining with an egg, copper acts as a spermicide within the uterus, increasing levels of copper ions, prostaglandins, and white blood cells within the uterine and tubal fluids. The increased copper ions in the cervical mucus inhibit the sperms motility and viability, preventing sperm from traveling through the cervical mucus, copper can also alter the endometrial lining, but studies show that this alteration can prevent implantation, but not disrupt implantation. Most copper IUDs have a plastic T-shaped frame that is wound around with pure electrolytic copper wire and/or has copper collars, the arms of the frame hold the IUD in place near the top of the uterus. The Paragard TCu 380a measures 32 mm horizontally, and 36 mm vertically, copper IUDs have a first year failure rate ranging from 0.1 to 2. 2%. In the Eurogine Gold T IUD, which is made in Spain, there is a gold core, GoldringMedusa is a differently-shaped German version of the Gold T. Another form of AuCu IUD is called Goldlily which is made by the Hungarian company, Goldlily consists of a layer of copper wires wrapped around an original layer of gold wires, and it provides electrochemical protection in addition to ionic protection. Radelkis also makes Silverlily, which is similar to Goldlily, nova-T380 contains a strengthening silver core, but does not incorporate silver ions themselves to provide electrochemical protection. Other shapes of IUD include the so-called U-shaped IUDs, such as the Load and Multiload, and it is held in place by a suture to the fundus of the uterus
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Sterilization (medicine)
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Sterilization is any of a number of medical techniques that intentionally leave a person unable to reproduce. It is a method of birth control, for other causes of sterility, see infertility. Sterilization methods include both surgical and non-surgical, and exist for males and females. Sterilization procedures are intended to be permanent, reversal is generally difficult or impossible, Sterilization is used all over the world by many different people. There are multiple ways of having sterilization done but the two that are used most frequently are, tubal sterilization and vasectomy, a vasectomy is one of the options a man has and a tubal sterilization is an option for women. There are many different ways tubal sterilization can be accomplished and it is extremely effective and in the United States surgical complications are low. With that being said, tubal sterilization is still a method that involves surgery, women that chose a tubal sterilization may have a higher risk of serious side effects, more than a man has with a vasectomy. Pregnancies after a tubal sterilization can still occur, even years after the procedure. It is not very likely, but if it does there is a high risk of ectopic gestation. Statistics confirm that a handful of tubal sterilization surgeries are performed shortly after a vaginal delivery mostly by minilaparotomy, in some cases, sterilization can be reversed but not all. It can vary by the type of sterilization performed, surgical sterilization methods include, Tubal ligation in females, known popularly as having ones tubes tied. The Fallopian tubes, which allow the sperm to fertilize the ovum and this generally involves a general anesthetic and a laparotomy or laparoscopic approach to cut, clip or cauterize the fallopian tubes. The vasa deferentia, the tubes that connect the testicles to the prostate, are cut and this prevents sperm produced in the testicles from entering the ejaculated semen. Although the term vasectomy is established in the community, the correct medical terminology is vasoligation. The uterus is surgically removed, permanently preventing pregnancy and some diseases and this is frequently used for the sterilization of animals, but rarely for humans. It was also used on some human male children for other reasons, see castrato. Transluminal procedures are performed by entry through the reproductive tract. These generally use a catheter to place a substance into the Fallopian tubes that eventually causes blockage of the tract in this segment, such procedures are generally called non-surgical as they use natural orifices and thereby do not necessitate any surgical incision
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Vasectomy
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Vasectomy is a surgical procedure for male sterilization or permanent contraception. During the procedure, the vas deferens are severed and then tied or sealed in a manner so as to prevent sperm from entering into the urethra. There are several methods by which a surgeon might complete a vasectomy procedure, due to the simplicity of the surgery, a vasectomy usually takes less than thirty minutes to complete. After a short recovery at the office, the patient is sent home to rest. Because the procedure is invasive, many vasectomy patients find that they can resume their typical sexual behavior within a week. The procedure is not often encouraged for young men as their chances for biological parenthood are thereby more or less permanently reduced to almost zero by it. It is seldom performed on dogs but is performed on bulls. A vasectomy is done to prevent fertility in males and it ensures that in most cases the person will be sterile after confirmation of success following surgery. The procedure is regarded as permanent because vasectomy reversal is costly, men with vasectomies have a very small chance of successfully impregnating a woman, but a vasectomy has no effect on rates of sexually transmitted infections. After vasectomy, the remain in the scrotum where Leydig cells continue to produce testosterone. Some studies have found that sexual desire after vasectomy may be somewhat diminished, when the vasectomy is complete, sperm cannot exit the body through the penis. Sperm are still produced by the testicles, but they are broken down. Much fluid content is absorbed by membranes in the epididymis, and much content is broken down by the responding macrophages. Sperm is matured in the epididymis for about a month before leaving the testicles, within one year after vasectomy, sixty to seventy per cent of vasectomized men develop antisperm antibodies. In some cases, vasitis nodosa, a proliferation of the ductular epithelium. The accumulation of sperm increases pressure in the vas deferens and epididymis, the entry of the sperm into the scrotum can cause sperm granulomas to be formed by the body to contain and absorb the sperm which the body will treat as a foreign biological substance. Late failure, i. e. pregnancy following spontaneous recanalization of the vasa deferentia, has also been documented, short-term possible complications include infection, bruising and bleeding into the scrotum resulting in a collection of blood known as a hematoma. A study in 2012 demonstrated a rate of 2. 5% postvasectomy
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Fetus
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A fetus is a stage in the prenatal development of viviparous organisms. In human development, a fetus or foetus is a human between the embryonic state and birth. The fetal stage of development tends to be taken as beginning at the age of eleven weeks. In biological terms, however, prenatal development is a continuum, the use of the term fetus generally implies that an embryo has developed to the point of being recognizable as a human, this is the point usually taken to be the ninth week after fertilization. A fetus is also characterized by the presence of all the body organs, though they will not yet be fully developed and functional. The word fetus is from the Latin fētus, the British, Irish, and Commonwealth spelling is foetus, which has been in use since at least 1594. It arose as a hypercorrection based on an incorrect etymology that may have originated with an error by Isidore of Seville in AD620 and this spelling is the most common in most Commonwealth nations, except in the medical literature, where fetus is used. The etymologically accurate original spelling fetus is used in Canada and the United States, in addition, fetus is now the standard English spelling throughout the world in medical journals. The spelling faetus was used historically, in humans, the fetal stage commences at the beginning of the ninth week. At the start of the stage, the fetus is typically about 30 millimetres in length from crown to rump. The head makes up half of the fetus size. Breathing-like movement of the fetus is necessary for stimulation of lung development, the heart, hands, feet, brain and other organs are present, but are only at the beginning of development and have minimal operation. The genitalia of the starts to form and placenta becomes fully functional during week 9. At this point in development, uncontrolled movements and twitches occur as muscles, the brain, and pathways begin to develop. A woman pregnant for the first time, typically feels fetal movements at about 21 weeks, whereas a woman who has given birth at least once, by the end of the fifth month, the fetus is about 20 cm long. The amount of body fat rapidly increases, thalamic brain connections, which mediate sensory input, form. Bones are fully developed, but are soft and pliable. Iron, calcium, and phosphorus become more abundant, fingernails reach the end of the fingertips
. PMID 23517858.
