|
Sex Selection
Sex selection is the attempt to control the sex of the offspring to achieve a desired sex. It can be accomplished in several ways, both pre- and post-implantation of an embryo, as well as at childbirth. It has been marketed under the title family balancing. According to the UNFPA, United Nations Population Fund, the reasons behind sex selection are due to three factors and provide an understanding for sex ratio imbalances as well as to project future trends. These factors are: # A preference for sons which stems from household structures "in which girls and women have a marginal social, economic and symbolic position, and consequently patriarchy, enjoy fewer rights." These household structures also focus on security in which sons are expected to provide support to their parents throughout their life; # Technological growth of prenatal diagnosis which allows parents to know the sex of their unborn child; and # Low fertility which increases the need for sex selection by reducing the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres (4-cell stage) are arranged as a solid ball that when reaching a certain size, called a morula, (16-cell stage) takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
One Child Policy
The one-child policy ( zh, c=一孩政策, p=yī hái zhèngcè) was a population planning initiative in China implemented between 1979 and 2015 to curb the country's population growth by restricting many families to a single child. The program had wide-ranging social, cultural, economic, and demographic effects, although the contribution of one-child restrictions to the broader program has been the subject of controversy. Its efficacy in reducing birth rates and defensibility from a human rights perspective have been subjects of controversy. China's family planning policies began to be shaped by fears of overpopulation in the 1970s, and officials raised the age of marriage and called for fewer and more broadly spaced births. A near-universal one-child limit was imposed in 1980 and written into the country's constitution in 1982. Numerous exceptions were established over time, and by 1984, only about 35.4% of the population was subject to the original restriction of the polic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Serum Albumin
Human serum albumin is the serum albumin found in human blood. It is the most abundant protein in human blood plasma; it constitutes about half of serum protein. It is produced in the liver. It is soluble in water, and it is monomeric. Albumin transports hormones, fatty acids, and other compounds, buffers pH, and maintains oncotic pressure, among other functions. Albumin is synthesized in the liver as preproalbumin, which has an N-terminal peptide that is removed before the nascent protein is released from the rough endoplasmic reticulum. The product, proalbumin, is in turn cleaved in the Golgi apparatus to produce the secreted albumin. The reference range for albumin concentrations in serum is approximately 35–50 g/L (3.5–5.0 g/dL). It has a serum half-life of approximately 21 days. It has a molecular mass of 66.5 kDa. The gene for albumin is located on chromosome 4 in locus 4q13.3 and mutations in this gene can result in anomalous proteins. The human alb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constituents Of Human Blood
{{Disambiguation ...
Constituent or constituency may refer to: Politics * An electoral district or constituency * Constituent, an individual citizen or voter represented by a politician within an electoral district, state, community, or organization * Advocacy group or constituency * Constituent assembly * Constituent state (territory, country, etc.): an administrative division of a larger state Other meanings * Constituent (linguistics), a word or a group of words that function as a single unit within a hierarchical structure * Constituent quark, a current quark with a notional "covering" See also * Ingredient * Part (other) Part, parts or PART may refer to: People *Part (surname) * Parts (surname) Arts, entertainment, and media * Part (music), a single strand or melody or harmony of music within a larger ensemble or a polyphonic musical composition * Part (bibliogr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Fertilization
Human fertilization is the union of an egg and sperm, occurring primarily in the ampulla of the fallopian tube. The result of this union leads to the production of a fertilized egg called a zygote, initiating embryonic development. Scientists discovered the dynamics of human fertilization in the 19th century. The process of fertilization involves a sperm fusing with an ovum. The most common sequence begins with ejaculation during copulation, follows with ovulation, and finishes with fertilization. Various exceptions to this sequence are possible, including artificial insemination, ''in vitro'' fertilization, external ejaculation without copulation, or copulation shortly after ovulation. Upon encountering the secondary oocyte, the acrosome of the sperm produces enzymes which allow it to burrow through the outer shell called the zona pellucida of the egg. The sperm plasma then fuses with the egg's plasma membrane and their nuclei fuse, triggering the sperm head to disconnect f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration
In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', '' molar concentration'', '' number concentration'', and '' volume concentration''. The concentration can refer to any kind of chemical mixture, but most frequently refers to solutes and solvents in solutions. The molar (amount) concentration has variants, such as normal concentration and osmotic concentration. Dilution is reduction of concentration, e.g. by adding solvent to a solution. The verb to concentrate means to increase concentration, the opposite of dilute. Etymology ''Concentration-'', ''concentratio'', action or an act of coming together at a single place, bringing to a common center, was used in post-classical Latin in 1550 or earlier, similar terms attested in Italian (1589), Spanish (1589), English (1606), French (1632). Qualitative description Often in informal, non- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clinic
A clinic (or outpatient clinic or ambulatory care clinic) is a health facility that is primarily focused on the care of outpatients. Clinics can be privately operated or publicly managed and funded. They typically cover the primary care needs of populations in local communities, in contrast to larger hospitals which offer more specialized treatments and admit inpatients for overnight stays. Most commonly, the English word ''clinic'' refers to a general practice, run by one or more general practitioners offering small therapeutic treatments, but it can also mean a specialty (medicine), specialist clinic. Some clinics retain the name "clinic" even while growing into institutions as large as major hospitals or becoming associated with a hospital or medical school. Etymology The word ''clinic'' derives from Ancient Greek ''klinein'' meaning to slope, lean or recline. Hence ''klinē'' is a couch or bed and ''klinikos'' is a physician who visits his patients in their beds. In L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ericsson Method
The Ericsson method is an assisted reproductive technology for sex selection, used before implantation. In this method, sperm that will give rise to male versus female children are separated by moving at different speeds through a protein solution. When used to increase the likelihood of a female child, studies have resulted in between 70% and 80% female children. When used to increase the likelihood of a male child, studies have resulted in between 50% and 75% male children. Method The Ericsson method is based on the belief that X-sperm swim slower than Y-sperm. Sperm are placed atop a "column" of increasingly thicker layers of albumin, and allowed to swim down into the solution. After a certain time period has elapsed, the sperm can be separated into the faster and slower swimmers. If the couple desires a male baby the faster swimmers are artificially inseminated, and if the couple desires a female baby the same procedure is enacted with the slower swimmers. This method diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Female
An organism's sex is female ( symbol: ♀) if it produces the ovum (egg cell), the type of gamete (sex cell) that fuses with the male gamete (sperm cell) during sexual reproduction. A female has larger gametes than a male. Females and males are results of the anisogamous reproduction system, wherein gametes are of different sizes (unlike isogamy where they are the same size). The exact mechanism of female gamete evolution remains unknown. In species that have males and females, sex-determination may be based on either sex chromosomes, or environmental conditions. Most female mammals, including female humans, have two X chromosomes. Characteristics of organisms with a female sex vary between different species, having different female reproductive systems, with some species showing characteristics secondary to the reproductive system, as with mammary glands in mammals. In humans, the word ''female'' can also be used to refer to gender in the social sense of gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X Chromosome
The X chromosome is one of the two sex chromosomes in many organisms, including mammals, and is found in both males and females. It is a part of the XY sex-determination system and XO sex-determination system. The X chromosome was named for its unique properties by early researchers, which resulted in the naming of its counterpart Y chromosome, for the next letter in the alphabet, following its subsequent discovery. Discovery It was first noted that the X chromosome was special in 1890 by Hermann Henking in Leipzig. Henking was studying the testicles of '' Pyrrhocoris'' and noticed that one chromosome did not take part in meiosis. Chromosomes are so named because of their ability to take up staining (''chroma'' in Greek means ''color''). Although the X chromosome could be stained just as well as the others, Henking was unsure whether it was a different class of the object and consequently named it ''X element'', which later became X chromosome after it was established that it w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Male
Male (Planet symbols, symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or Egg cell, ovum, in the process of fertilisation. A male organism cannot sexual reproduction, reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and Asexual reproduction, asexually. Most male mammals, including male humans, have a Y chromosome, which codes for the production of larger amounts of testosterone to develop male reproductive organs. In humans, the word ''male'' can also be used to refer to gender, in the social sense of gender role or gender identity. Overview The existence of separate sexes has evolved independently at different times and in different lineage (evolution), lineages, an example of convergent evolution. The repeated pattern is sexual reproduction in isogamy, isogamous species with two or more mating types with gametes of identic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y Chromosome
The Y chromosome is one of two sex chromosomes in therian mammals and other organisms. Along with the X chromosome, it is part of the XY sex-determination system, in which the Y is the sex-determining chromosome because the presence of the Y chromosome causes offspring produced in sexual reproduction to be of male sex. In mammals, the Y chromosome contains the SRY gene, which triggers development of male gonads. The Y chromosome is passed only from male parents to male offspring. Overview Discovery The Y chromosome was identified as a sex-determining chromosome by Nettie Stevens at Bryn Mawr College in 1905 during a study of the mealworm ''Tenebrio molitor''. Edmund Beecher Wilson independently discovered the same mechanisms the same year, working with Hemiptera. Stevens proposed that chromosomes always existed in pairs and that the smaller chromosome (now labelled "Y") was the pair of the X chromosome discovered in 1890 by Hermann Henking. She realized that th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
