vania-janet/multiturn-rag-retrieval-data huggingface dataset:
Thymus
The thymus continues to grow between birth and puberty and then begins to atrophy , called thymic involution . The process accelerates after puberty , thymus decreases both in size and activity , and the tissue of the thymus is primarily replaced with fat ( a phenomenon known as `` organ involution '' ) . The atrophy is due to the increased circulating level of sex hormones , and chemical or physical castration of an adult results in the thymus increasing in size and activity . Fat cells are first visible in the walls between lobules , and then slowly spread throughout the cortex and then medulla .
Cell cycle
Before a cell can enter cell division , it needs to take in nutrients . All of the preparations are done during interphase . Interphase is a series of changes that takes place in a newly formed cell and its nucleus , before it becomes capable of division again . It is also called preparatory phase or intermitosis . Previously it was called resting stage because there is no apparent activity related to cell division. Typically interphase lasts for at least 91 % of the total time required for the cell cycle .
Polistes carolina
The reproductive phase lasts from the emergence of the first reproductives until the colony begins to decline and new reproductives disperse to form their own nests . During this time , each foundress mates with a different male and lays her eggs , with the dominant foundress laying the majority of the eggs .
Cell cycle
G2 phase occurs after DNA replication and is a period of protein synthesis and rapid cell growth to prepare the cell for mitosis . During this phase microtubules begin to reorganize to form a spindle .
Estrogen
Verbal memory scores are frequently used as one measure of higher level cognition . These scores vary in direct proportion to estrogen levels throughout the menstrual cycle , pregnancy , and menopause . Furthermore , estrogens when administered shortly after natural or surgical menopause prevents decreases in verbal memory . In contrast , estrogens have little effect on verbal memory if first administered years after menopause . Estrogens also have positive influences on other measures of cognitive function . However the effect of estrogens on cognition is not uniformly favorable and is dependent on the timing of the dose and the type of cognitive skill being measured .
Adolescence
The adolescent growth spurt is a rapid increase in the individual 's height and weight during puberty resulting from the simultaneous release of growth hormones , thyroid hormones , and androgens . Males experience their growth spurt about two years later , on average , than females . During their peak height velocity ( the time of most rapid growth ) , adolescents grow at a growth rate nearly identical to that of a toddler -- about 4 inches ( 10.3 cm ) a year for males and 3.5 inches ( 9 cm ) for females . In addition to changes in height , adolescents also experience a significant increase in weight ( Marshall , 1978 ) . The weight gained during adolescence constitutes nearly half of one 's adult body weight . Teenage and early adult males may continue to gain natural muscle growth even after puberty .
Population pyramid
A population pyramid gives a clear picture of how a country transitions from high fertility to low fertility rate . The broad base of the pyramid means the majority of population lies between ages 0 -- 14 , which tells us that the fertility rate of the country is high and above population sub-replacement fertility level . The older population is declining over time due to a shorter life expectancy of sixty years . However , there are still more females than males in these ranges since women have a longer life expectancy . As reported by the Proceedings of the National Academy of Sciences , women tend to live longer than men because women do not partake in risky behaviors . Also , Weeks ' Population : an Introduction to Concepts and Issues , considered that the sex ratio gap for the older ages will shrink due to women 's health declining due to the effects of smoking , as suggested by the United Nations and U.S. Census Bureau . Moreover , it can also reveal the age - dependency ratio of a population . Populations with a big base , young population , or a big top , an older population , shows that there is a higher dependency ratio . The dependency ratio refers to how many people are dependent on the working class ( ages 15 - 64 ) . According to Weeks ' Population : an Introduction to Concepts and Issues , population pyramids can be used to predict the future , known as a population forecast . Population momentum , when a population 's birth rates continue to increase even after replacement level has been reached , can even be predicted if a population has a low mortality rate since the population will continue to grow . This then brings up the term doubling time , which is used to predict when the population will double in size . Lastly , a population pyramid can even give insight on the economic status of a country from the age stratification since the distribution of supplies are not evenly distributed through a population .
Society of the United States
Adolescent sex is common ; most Americans first have sexual intercourse in their teenage years . The current data suggests that by the time a person turns eighteen years old , slightly more than half of females and nearly two - thirds of males will have had sexual relations . More than half of sexually active teens have had sexual partners they are dating . Risky sexual behaviors that involve `` anything intercourse related '' are `` rampant '' among teenagers . Teenage pregnancies in the United States decreased 28 % between 1990 - 2000 from 117 pregnancies per every 1,000 teens to 84 per 1,000 . The United States is rated , based on 2002 estimates , 84 out of 170 countries based on teenage fertility rate , according to the World Health Organization .
Chernobyl disaster
Well - differentiated thyroid cancers are generally treatable , and when treated the five - year survival rate of thyroid cancer is 96 % , and 92 % after 30 years . UNSCEAR had reported 15 deaths from thyroid cancer in 2011 . The International Atomic Energy Agency ( IAEA ) also states that there has been no increase in the rate of birth defects or abnormalities , or solid cancers ( such as lung cancer ) corroborating UNSCEAR 's assessments . UNSCEAR does raise the possibility of long term genetic defects , pointing to a doubling of radiation - induced minisatellite mutations among children born in 1994 . However , the risk of thyroid cancer associated with the Chernobyl accident is still high according to published studies .
Genetic recombination
Molecular models of meiotic recombination have evolved over the years as relevant evidence accumulated . A major incentive for developing a fundamental understanding of the mechanism of meiotic recombination is that such understanding is crucial for solving the problem of the adaptive function of sex , a major unresolved issue in biology . A recent model that reflects current understanding was presented by Anderson and Sekelsky , and is outlined in the first figure in this article . The figure shows that two of the four chromatids present early in meiosis ( prophase I ) are paired with each other and able to interact . Recombination , in this version of the model , is initiated by a double - strand break ( or gap ) shown in the DNA molecule ( chromatid ) at the top of the first figure in this article . However , other types of DNA damage may also initiate recombination . For instance , an inter-strand cross-link ( caused by exposure to a cross-linking agent such as mitomycin C ) can be repaired by HRR .
Birth control in the United States
Contraception has many benefits beyond preventing pregnancy . Combination estrogen - progestin contraceptives can successfully treat dysmenorrhea ( painful periods ) , provide symptom relief from endometriosis , reduce heavy menstrual bleeding and improve anemia related to menstrual blood loss , reduce symptoms of premenstrual syndrome and premenstrual dysphoric disorder , reduce ovarian and colon cancer risk , reduce moderate acne , prevent of menstrual migraines , and reduce hirsutism ( abnormal hair growth ) . The progestin containing intrauterine device can reduce heavy menstrual bleeding and protect against pre-cancerous changes or cancer in the uterus . Condoms ( male or female ) are the only contraceptive method which protects against acquisition of sexually transmitted infections .
Atomic bombings of Hiroshima and Nagasaki
As cancers do not immediately emerge after exposure to radiation instead radiation - induced cancer has a minimum latency period of some 5 + years . An epidemiology study by the RERF estimates that from 1950 to 2000 , 46 % of leukemia deaths and 11 % of solid cancers of unspecificed lethality , could be due to radiation from the bombs , with the statistical excess being 200 leukemia deaths and 1,700 solid cancers of undeclared lethality . Both of these statistics being derived from the observation of approximately half of the total survivors , strictly those who took part in the study .
Estrogen
Estrogens are responsible for maturation and maintenance of the vagina and uterus , and are also involved in ovarian function , such as maturation of ovarian follicles . In addition , estrogens play an important role in regulation of gonadotropin secretion . For these reasons , estrogens are required for female fertility .
Testosterone
18 years ND ND -- -- Premenopausal -- -- 1.9 -- 22.8 ng / dL 0.066 -- 0.791 nmol / L Postmenopausal -- -- 1.6 -- 19.1 ng / dL 0.055 -- 0.662 nmol / L Total testosterone Stage Age range Male Female Values SI units Values SI units Infant Premature ( 26 -- 28 weeks ) 59 -- 125 ng / dL 2.047 -- 4.337 nmol / L 5 -- 16 ng / dL 0.173 -- 0.555 nmol / L Premature ( 31 -- 35 weeks ) 37 -- 198 ng / dL 1.284 -- 6.871 nmol / L 5 -- 22 ng / dL 0.173 -- 0.763 nmol / L Newborn 75 -- 400 ng / dL 2.602 -- 13.877 nmol / L 20 -- 64 ng / dL 0.694 -- 2.220 nmol / L Child 1 -- 6 years ND ND ND ND 7 -- 9 years 0 -- 8 ng / dL 0 -- 0.277 nmol / L 1 -- 12 ng / dL 0.035 -- 0.416 nmol / L Just before puberty 3 -- 10 ng / dL * 0.104 -- 0.347 nmol / L * < 10 ng / dL * < 0.347 nmol / L * Puberty 10 -- 11 years 1 -- 48
Germ cell
Under special conditions in vitro germ cells can acquire properties similar to those of embryonic stem cells ( ES ) . The underlying mechanism of that change is still unknown . These changed cells are then called embryonic germ cells ( EG ) . Both EG and ES are pluripotent in vitro , but only ES has proven pluripotency in vivo . Recent studies have demonstrated that it is possible to give rise to primordial germ cells from ES .
Ultraviolet
The evolution of early reproductive proteins and enzymes is attributed in modern models of evolutionary theory to ultraviolet radiation . UVB causes thymine base pairs next to each other in genetic sequences to bond together into thymine dimers , a disruption in the strand that reproductive enzymes can not copy . This leads to frameshifting during genetic replication and protein synthesis , usually killing the cell . Before formation of the UV - blocking ozone layer , when early prokaryotes approached the surface of the ocean , they almost invariably died out . The few that survived had developed enzymes that monitored the genetic material and removed thymine dimers by nucleotide excision repair enzymes . Many enzymes and proteins involved in modern mitosis and meiosis are similar to repair enzymes , and are believed to be evolved modifications of the enzymes originally used to overcome DNA damages caused by UV .
Hormonal contraception
There is a mixed effect of combined hormonal contraceptives on the rates of various cancers , with the International Agency for Research on Cancer ( IARC ) stating : `` It was concluded that , if the reported association was causal , the excess risk for breast cancer associated with typical patterns of current use of combined oral contraceptives was very small . '' and also saying that `` there is also conclusive evidence that these agents have a protective effect against cancers of the ovary and endometrium '' : The ( IARC ) notes that `` the weight of the evidence suggests a small increase in the relative risk for breast cancer among current and recent users '' which following discontinuation then lessens over a period of 10 years to similar rates as women who never used them , as well as `` The increase in risk for breast cancer associated with the use of combined oral contraceptives in younger women could be due to more frequent contacts with doctors '' Small increases are also seen in the rates of cervical cancer and hepatocellular ( liver ) tumours . Endometrial and ovarian cancer risks are approximately halved and persists for at least 10 years after cessation of use ; although `` sequential oral contraceptives which were removed from the consumer market in the 1970s was associated with an increased risk for endometrial cancer '' . Studies have overall not shown effects on the relative risks for colorectal , malignant melanoma or thyroid cancers . Information on progesterone - only pills is less extensive , due to smaller sampling sizes , but they do not appear to significantly increase the risk of breast cancer . Most other forms of hormonal contraception are too new for meaningful data to be available , although risks and benefits are believed to be similar for methods which use the same hormones ; e.g. , risks for combined - hormone patches are thought to be roughly equivalent to those for combined - hormone pills .
Asexual reproduction
Fungi and some algae can also utilize true asexual spore formation , which involves mitosis giving rise to reproductive cells called mitospores that develop into a new organism after dispersal . This method of reproduction is found for example in conidial fungi and the red algae Polysiphonia , and involves sporogenesis without meiosis . Thus the chromosome number of the spore cell is the same as that of the parent producing the spores . However , mitotic sporogenesis is an exception and most spores , such as those of plants , most Basidiomycota , and many algae , are produced by meiosis .
Cell cycle
Active S cyclin - CDK complexes phosphorylate proteins that make up the pre-replication complexes assembled during G phase on DNA replication origins . The phosphorylation serves two purposes : to activate each already - assembled pre-replication complex , and to prevent new complexes from forming . This ensures that every portion of the cell 's genome will be replicated once and only once . The reason for prevention of gaps in replication is fairly clear , because daughter cells that are missing all or part of crucial genes will die . However , for reasons related to gene copy number effects , possession of extra copies of certain genes is also deleterious to the daughter cells .
Female reproductive system
The reproductive tract ( or genital tract ) is the lumen that starts as a single pathway through the vagina , splitting up into two lumens in the uterus , both of which continue through the Fallopian tubes , and ending at the distal ostia that open into the abdominal cavity .
Testosterone
Testosterone does not appear to increase the risk of developing prostate cancer . In people who have undergone testosterone deprivation therapy , testosterone increases beyond the castrate level have been shown to increase the rate of spread of an existing prostate cancer .
Fukushima Daiichi nuclear disaster
A 2018 publication by Yamashita et al. has also concluded that attribution of Thyroid cancers can also be attributed to the screening effect . They noted that the mean age of the patients at the time of the accident was 10 -- 15 years , while no cases were found in children from the ages of 0 - 5 who would have been most susceptible . Yamashita et al. thus conclude that `` In any case , the individual prognosis can not be accurately determined at the time of FNAC at present . It is therefore urgent to search not only for intraoperative and postoperative prognostic factors but also for predictive prognostic factors at the FNAC / preoperative stage . ''
Stem cell
2 . Stochastic differentiation : when one stem cell develops into two differentiated daughter cells , another stem cell undergoes mitosis and produces two stem cells identical to the original .
Asexual reproduction
Parthenogenesis is a form of agamogenesis in which an unfertilized egg develops into a new individual . Parthenogenesis occurs naturally in many plants , invertebrates ( e.g. water fleas , rotifers , aphids , stick insects , some ants , bees and parasitic wasps ) , and vertebrates ( e.g. some reptiles , amphibians , rarely birds ) . In plants , apomixis may or may not involve parthenogenesis . Apomixis
Adolescence
The first areas of the brain to be pruned are those involving primary functions , such as motor and sensory areas . The areas of the brain involved in more complex processes lose matter later in development . These include the lateral and prefrontal cortices , among other regions . Some of the most developmentally significant changes in the brain occur in the prefrontal cortex , which is involved in decision making and cognitive control , as well as other higher cognitive functions . During adolescence , myelination and synaptic pruning in the prefrontal cortex increases , improving the efficiency of information processing , and neural connections between the prefrontal cortex and other regions of the brain are strengthened . This leads to better evaluation of risks and rewards , as well as improved control over impulses . Specifically , developments in the dorsolateral prefrontal cortex are important for controlling impulses and planning ahead , while development in the ventromedial prefrontal cortex is important for decision making . Changes in the orbitofrontal cortex are important for evaluating rewards and risks .
Homologous chromosome
After the tetrads of homologous chromosomes are separated in meiosis I , the sister chromatids from each pair are separated . The two haploid ( because the chromosome no. has reduced to half . Earlier two sets of chromosomes were present , but now each set exists in two different daughter cells that have arisen from the single diploid parent cell by meiosis I ) daughter cells resulting from meiosis I undergo another cell division in meiosis II but without another round of chromosomal replication . The sister chromatids in the two daughter cells are pulled apart during anaphase II by nuclear spindle fibers , resulting in four haploid daughter cells .
Endocrine system
Secreted hormone Abbreviation From cells Effect Progesterone ( Primarily ) Support pregnancy : Inhibit immune response , towards the fetus . Decrease uterine smooth muscle contractility Inhibit lactation Inhibit onset of labor . Support fetal production of adrenal mineralo - and glucosteroids . Other effects on mother similar to ovarian follicle - progesterone Estrogens ( mainly Estriol ) ( Also Primarily ) Effects on mother similar to ovarian follicle estrogen Human chorionic gonadotropin HCG Syncytiotrophoblast Promote maintenance of corpus luteum during beginning of pregnancy Inhibit immune response , towards the human embryo . Human placental lactogen HPL Syncytiotrophoblast Increase production of insulin and IGF - 1 Increase insulin resistance and carbohydrate intolerance Inhibin Fetal Trophoblasts Suppress FSH Uterus
Hormonal contraception
Estrogen was originally included in oral contraceptives for better cycle control ( to stabilize the endometrium and thereby reduce the incidence of breakthrough bleeding ) , but was also found to inhibit follicular development and help prevent ovulation . Estrogen negative feedback on the anterior pituitary greatly decreases the release of FSH , which inhibits follicular development and helps prevent ovulation .
Germ cell
Hayashi and Saitou 's group was able to promote the differentiation of embryonic stem cells into PGCs with the use of precise timing and bone morphogenetic protein 4 ( Bmp4 ) . Upon succeeding with embryonic stem cells , the group was able to successfully promote the differentiation of induced pluripotent stem cells ( iPSCs ) into PGCs . These primordial germ cell - like cells were then used to create spermatozoa and oocytes .
Asexual reproduction
For example , the slime mold Dictyostelium undergoes binary fission ( mitosis ) as single - celled amoebae under favorable conditions . However , when conditions turn unfavorable , the cells aggregate and follow one of two different developmental pathways , depending on conditions . In the social pathway , they form a multicellular slug which then forms a fruiting body with asexually generated spores . In the sexual pathway , two cells fuse to form a giant cell that develops into a large cyst . When this macrocyst germinates , it releases hundreds of amoebic cells that are the product of meiotic recombination between the original two cells .
Estrogen
The estrogen - alone substudy of the WHI reported an increased risk of stroke and deep vein thrombosis ( DVT ) in postmenopausal women 50 years of age or older and an increased risk of dementia in postmenopausal women 65 years of age or older using 0.625 mg of Premarin conjugated equine estrogens ( CEE ) . The estrogen - plus - progestin substudy of the WHI reported an increased risk of myocardial infarction , stroke , invasive breast cancer , pulmonary emboli and DVT in postmenopausal women 50 years of age or older and an increased risk of dementia in postmenopausal women 65 years of age or older using PremPro , which is 0.625 mg of CEE with 2.5 mg of the progestin medroxyprogesterone acetate ( MPA ) .
Cell division
Telophase is the last stage of the cell cycle . Two cells form around the chromatin at the two poles of the cell . Two nuclear membranes begin to reform and the chromatin begin to unwind .
Hormonal contraception
Intermediate dose progestogen - only contraceptives , such as the progestogen - only pill Cerazette ( or the subdermal implant Implanon ) , allow some follicular development but much more consistently inhibit ovulation in 97 -- 99 % of cycles . The same cervical mucus changes occur as with low dose progestogens .
Eukaryote
Eukaryotes can reproduce both asexually through mitosis and sexually through meiosis and gamete fusion . In mitosis , one cell divides to produce two genetically identical cells . In meiosis , DNA replication is followed by two rounds of cell division to produce four haploid daughter cells . These act as sex cells ( gametes ) . Each gamete has just one set of chromosomes , each a unique mix of the corresponding pair of parental chromosomes resulting from genetic recombination during meiosis .
Homologous chromosome
In the process of crossing - over , genes are exchanged by the breaking and union of homologous portions of the chromosomes ' lengths . Structures called chiasmata are the site of the exchange . Chiasmata physically link the homologous chromosomes once crossing over occurs and throughout the process of chromosomal segregation during meiosis . Both the non-crossover and crossover types of recombination function as processes for repairing DNA damage , particularly double - strand breaks . At the diplotene stage of prophase I the synaptonemal complex disassembles before which will allow the homologous chromosomes to separate , while the sister chromatids stay associated by their centromeres . Metaphase
Apoptosis
The tumor - suppressor protein p53 accumulates when DNA is damaged due to a chain of biochemical factors . Part of this pathway includes alpha - interferon and beta - interferon , which induce transcription of the p53 gene , resulting in the increase of p53 protein level and enhancement of cancer cell - apoptosis . p53 prevents the cell from replicating by stopping the cell cycle at G1 , or interphase , to give the cell time to repair , however it will induce apoptosis if damage is extensive and repair efforts fail . Any disruption to the regulation of the p53 or interferon genes will result in impaired apoptosis and the possible formation of tumors .