A woman's menstrual cycle begins, as it has been arbitrarily assigned, with menses. Next is the follicular phase where estrogen levels build as an ovum matures (due to the follicular stimulating hormone, or FSH) within the ovary. When estrogen levels peak, it spurs a surge of luteinizing hormone (LH) which finishes the ovum and enables it to break through the ovary wall.

This is ovulation. During the luteal phase, which follows ovulation LH and FSH cause the post-ovulation ovary to develop into the corpus luteum which produces progesterone. The production of progesterone inhibits the LH and FSH hormones which (in a cycle sans pregnancy)causes the corpus luteum to atrophy, and menses to begin the cycle again.

Peak fertility occurs during just a few days of the cycle: usually two days before and two days after the ovulation date. This fertile window varies from woman to woman, just as the ovulation date often varies from cycle to cycle for the same woman. The ovule is usually capable of being fertilized for up to 48 hours after it is released from the ovary. Sperm survive inside the uterus between 48 to 72 hours on average, with the maximum being 120 hours (5 days).

These periods and intervals are important factors for couples using the rhythm method of contraception.

Men and women have hormonal cycles which determine both when a woman can achieve pregnancy and when a man is most virile. The female cycle is approximately twenty-eight days long, but can deviate greatly from this "norm". The male cycle is also variable. Men can ejaculate and produce sperm at any time of the month, but their sperm quality dips occasionally, which scientists guess is in relation to their internal cycle.

Furthermore, age also plays an equally significant role for both men and women.
In demographic contexts, fertility refers to the actual production of offspring, rather than the physical capability to produce which is termed fecundity. While fertility can be measured, fecundity cannot be. Demographers measure the fertility rate in a variety of ways.

which can be broadly broken into "period" measures and "cohort" measures. "Period" measures refer to a cross-section of the population in one year. "Cohort" data on the other hand, follows the same people over a period of decades. Both period and cohort measures are widely used.(wikipedia.org)


Psychology depicts love as a cognitive and social phenomenon. Psychologist Robert Sternberg formulated a triangular theory of love and argued that love has three different components: intimacy, commitment, and passion. Intimacy is a form in which two people share confidences and various details of their personal lives, and is usually shown in friendships and romantic love affairs.

Commitment, on the other hand, is the expectation that the relationship is permanent. The last and most common form of love is sexual attraction and passion. Passionate love is shown in infatuation as well as romantic love. All forms of love are viewed as varying combinations of these three components. Non-love does not include any of these components.

Liking only includes intimacy. Infatuated love only includes passion. Empty love only includes commitment. Romantic love includes both intimacy and passion. Companionate love includes intimacy and commitment. Fatuous love includes passion and commitment. Lastly, consummate love includes all three. American psychologist Zick Rubin sought to define love by psychometrics in the 1970s. His work states that three factors constitute love: attachment, caring, and intimacy.

Following developments in electrical theories such as Coulomb's law, which showed that positive and negative charges attract, analogs in human life were developed, such as "opposites attract." Over the last century, research on the nature of human mating has generally found this not to be true when it comes to character and personality—people tend to like people similar to themselves.

However, in a few unusual and specific domains, such as immune systems, it seems that humans prefer others who are unlike themselves (e.g., with an orthogonal immune system), since this will lead to a baby that has the best of both worlds. In recent years, various human bonding theories have been developed, described in terms of attachments, ties, bonds, and affinities. Some Western authorities disaggregate into two main components, the altruistic and the narcissistic.

This view is represented in the works of Scott Peck, whose work in the field of applied psychology explored the definitions of love and evil. Peck maintains that love is a combination of the "concern for the spiritual growth of another," and simple narcissism. In combination, love is an activity, not simply a feeling.

Psychologist Erich Fromm maintained in his book The Art of Loving that love is not merely a feeling but is also actions, and that in fact, the "feeling" of love is superficial in comparison to one's commitment to love via a series of loving actions over time. In this sense, Fromm held that love is ultimately not a feeling at all, but rather is a commitment to, and adherence to, loving actions towards another, oneself, or many others, over a sustained duration.

Fromm also described love as a conscious choice that in its early stages might originate as an involuntary feeling, but which then later no longer depends on those feelings, but rather depends only on conscious commitment.(wikipedia.org)


Cancer pathogenesis is traceable back to DNA mutations that impact cell growth and metastasis. Substances that cause DNA mutations are known as mutagens, and mutagens that cause cancers are known as carcinogens. Particular substances have been linked to specific types of cancer.

Tobacco smoking is associated with many forms of cancer, Many mutagens are also carcinogens, but some carcinogens are not mutagens. Alcohol is an example of a chemical carcinogen that is not a mutagen. In Western Europe 10% of cancers in males and 3% of cancers in females are attributed to alcohol.

Decades of research has demonstrated the link between tobacco use and cancer in the lung, larynx, head, neck, stomach, bladder, kidney, esophagus and pancreas. Tobacco smoke contains over fifty known carcinogens, including nitrosamines and polycyclic aromatic hydrocarbons.


Tobacco is responsible for about one in three of all cancer deaths in the developed world, and about one in five worldwide. Lung cancer death rates in the United States have mirrored smoking patterns, with increases in smoking followed by dramatic increases in lung cancer death rates and, more recently, decreases in smoking rates since the 1950s followed by decreases in lung cancer death rates in men since 1990. However, the numbers of smokers worldwide is still rising, leading to what some organizations have described as the tobacco epidemic.

Cancer related to one's occupation is believed to represent between 2–20% of all cases. Every year, at least 200,000 people die worldwide from cancer related to their workplace. Most cancer deaths caused by occupational risk factors occur in the developed world. It is estimated that approximately 20,000 cancer deaths and 40,000 new cases of cancer each year in the U.S. are attributable to occupation.

Millions of workers run the risk of developing cancers such as lung cancer and mesothelioma from inhaling asbestos fibers and tobacco smoke, or leukemia from exposure to benzene at their workplaces.

Up to 10% of invasive cancers are related to radiation exposure, including both ionizing radiation and non-ionizing ultraviolet radiation. Additionally, the vast majority of non-invasive cancers are non-melanoma skin cancers caused by non-ionizing ultraviolet radiation.

Sources of ionizing radiation include medical imaging, and radon gas. Radiation can cause cancer in most parts of the body, in all animals, and at any age, although radiation-induced solid tumors usually take 10–15 years, and can take up to 40 years, to become clinically manifest, and radiation-induced leukemias typically require 2–10 years to appear.

Some people, such as those with nevoid basal cell carcinoma syndrome or retinoblastoma, are more susceptible than average to developing cancer from radiation exposure. Children and adolescents are twice as likely to develop radiation-induced leukemia as adults; radiation exposure before birth has ten times the effect. Ionizing radiation is not a particularly strong mutagen.

Residential exposure to radon gas, for example, has similar cancer risks as passive smoking. Low-dose exposures, such as living near a nuclear power plant, are generally believed to have no or very little effect on cancer development. Radiation is a more potent source of cancer when it is combined with other cancer-causing agents, such as radon gas exposure plus smoking tobacco.
Unlike chemical or physical triggers for cancer, ionizing radiation hits molecules within cells randomly.

If it happens to strike a chromosome, it can break the chromosome, result in an abnormal number of chromosomes, inactivate one or more genes in the part of the chromosome that it hit, delete parts of the DNA sequence, cause chromosome translocations, or cause other types of chromosome abnormalities.

Major damage normally results in the cell dying, but smaller damage may leave a stable, partly functional cell that may be capable of proliferating and developing into cancer, especially if tumor suppressor genes were damaged by the radiation.

Three independent stages appear to be involved in the creation of cancer with ionizing radiation: morphological changes to the cell, acquiring cellular immortality (losing normal, life-limiting cell regulatory processes), and adaptations that favor formation of a tumor. Even if the radiation particle does not strike the DNA directly, it triggers responses from cells that indirectly increase the likelihood of mutations.(wikipedia.org)


Viruses can replicate only in living cells. Influenza infection and replication is a multi-step process: First, the virus has to bind to and enter the cell, then deliver its genome to a site where it can produce new copies of viral proteins and RNA, assemble these components into new viral particles, and, last, exit the host cell.

Influenza viruses bind through hemagglutinin onto sialic acid sugars on the surfaces of epithelial cells, typically in the nose, throat, and lungs of mammals, and intestines of birds (Stage 1 in infection figure). After the hemagglutinin is cleaved by a protease, the cell imports the virus by endocytosis.

The intracellular details are still being elucidated. It is known that virions converge to the microtubule organizing center, interact with acidic endosomes and finally enter the target endosomes for genome release.

Once inside the cell, the acidic conditions in the endosome cause two events to happen: First, part of the hemagglutinin protein fuses the viral envelope with the vacuole's membrane, then the M2 ion channel allows protons to move through the viral envelope and acidify the core of the virus, which causes the core to dissemble and release the viral RNA and core proteins.

The viral RNA (vRNA) molecules, accessory proteins and RNA-dependent RNA polymerase are then released into the cytoplasm (Stage 2). The M2 ion channel is blocked by amantadine drugs, preventing infection.

These core proteins and vRNA form a complex that is transported into the cell nucleus, where the RNA-dependent RNA polymerase begins transcribing complementary positive-sense vRNA (Steps 3a and b).

The vRNA either is exported into the cytoplasm and translated (step 4) or remains in the nucleus. Newly synthesized viral proteins are either secreted through the Golgi apparatus onto the cell surface (in the case of neuraminidase and hemagglutinin, step 5b) or transported back into the nucleus to bind vRNA and form new viral genome particles (step 5a).

Other viral proteins have multiple actions in the host cell, including degrading cellular mRNA and using the released nucleotides for vRNA synthesis and also inhibiting translation of host-cell mRNAs.

Negative-sense vRNAs that form the genomes of future viruses, RNA-dependent RNA polymerase, and other viral proteins are assembled into a virion. Hemagglutinin and neuraminidase molecules cluster into a bulge in the cell membrane.

The vRNA and viral core proteins leave the nucleus and enter this membrane protrusion (step 6). The mature virus buds off from the cell in a sphere of host phospholipid membrane, acquiring hemagglutinin and neuraminidase with this membrane coat (step 7).

As before, the viruses adhere to the cell through hemagglutinin; the mature viruses detach once their neuraminidase has cleaved sialic acid residues from the host cell. After the release of new influenza viruses, the host cell dies.

Because of the absence of RNA proofreading enzymes, the RNA-dependent RNA polymerase that copies the viral genome makes an error roughly every 10 thousand nucleotides, which is the approximate length of the influenza vRNA. Hence, the majority of newly manufactured influenza viruses are mutants; this causes antigenic drift, which is a slow change in the antigens on the viral surface over time.

The separation of the genome into eight separate segments of vRNA allows mixing or reassortment of vRNAs if more than one type of influenza virus infects a single cell. The resulting rapid change in viral genetics produces antigenic shifts, which are sudden changes from one antigen to another.

These sudden large changes allow the virus to infect new host species and quickly overcome protective immunity This is important in the emergence of pandemics, as discussed below in the section on Epidemiology. (wikipedia.org)


The first known attempt at European colonization began when Norsemen settled briefly at L'Anse aux Meadows in Newfoundland around 1000 AD. No further European exploration occurred until 1497, when Italian seafarer John Cabot explored Canada's Atlantic coast for England

Basque and Portuguese mariners established seasonal whaling and fishing outposts along the Atlantic coast in the early 16th century. In 1534, French explorer Jacques Cartier explored the St. Lawrence River, where on July 24 he planted a 10-metre (33 ft) cross bearing the words "Long Live the King of France", and took possession of the territory in the name of King Francis I.

In 1583, Sir Humphrey Gilbert claimed St. John's, Newfoundland, as the first North American English colony by the royal prerogative of Queen Elizabeth I French explorer Samuel de Champlain arrived in 1603, and established the first permanent European settlements at Port Royal in 1605 and Quebec City in 1608.


Among the French colonists of New France, Canadiens extensively settled the St. Lawrence River valley and Acadians settled the present-day Maritimes, while fur traders and Catholic missionaries explored the Great Lakes, Hudson Bay, and the Mississippi watershed to Louisiana.

The Beaver Wars broke out in the mid-17th century over control of the North American fur trade.
The English established additional colonies in Cupids and Ferryland, Newfoundland, beginning in 1610.

The Thirteen Colonies to the south were founded soon after. A series of four wars erupted in colonial North America between 1689 and 1763; the later wars of the period constituted the North American theatre of the Seven Years' War. Mainland Nova Scotia came under British rule with the 1713 Treaty of Utrecht; the Treaty of Paris (1763) ceded Canada and most of New France to Britain after the Seven Years' War.

The Royal Proclamation of 1763 created the Province of Quebec out of New France, and annexed Cape Breton Island to Nova Scotia. St. John's Island (now Prince Edward Island) became a separate colony in 1769. To avert conflict in Quebec, the British passed the Quebec Act of 1774, expanding Quebec's territory to the Great Lakes and Ohio Valley.

 It re-established the French language, Catholic faith, and French civil law there. This angered many residents of the Thirteen Colonies, fuelling anti-British sentiment in the years prior to the 1775 outbreak of the American Revolution.

The 1783 Treaty of Paris recognized American independence and ceded territories south of the Great Lakes to the United States. New Brunswick was split from Nova Scotia as part of a reorganization of Loyalist settlements in the Maritimes.

To accommodate English-speaking Loyalists in Quebec, the Constitutional Act of 1791 divided the province into French-speaking Lower Canada (later Quebec) and English-speaking Upper Canada (later Ontario), granting each its own elected legislative assembly.(wikipedia.org)


The spelling of woman in English has progressed over the past millennium from wīfmann to wīmmann to wumman, and finally, the modern spelling woman. Old English wīfmann meant "female human, whereas wēr meant male human.

Mann or monn had a gender-neutral meaning of human, corresponding to Modern English person or someone, however subsequent to the Norman Conquest, man began to be used more in reference to male human, and by the late 1200s had begun to eclipse usage of the older term wēr.

The medial labial consonants f and m in wīfmann coalesced into the modern form woman, while the initial element, which meant female, underwent semantic narrowing to the sense of a married woman ("wife").


It is a popular misconception that the term woman is etymologically connected with womb, which is from a separate Old English word, wambe meaning stomach (of male or female).

Nevertheless, such a false derivation of woman has appeared in print.
A very common Indo-European root for woman, is the source of modern English queen (Old English cwēn had primarily meant woman, highborn or not; this is still the case in Danish, with the modern spelling kvinde, as well as in Swedish kvinna).

The word gynaecology is also derived from the Ancient Greek cognate, woman. Other English words traceable to the same Indo-European root include banshee fairy woman (from Irish bean woman and "fairy") and zenana (from Persian زن zan).

The Latin fēmina, whence female, is likely from the root in fellāre (to suck), in reference to breastfeeding.

Biological symbol

The symbol for the planet Venus is the sign also used in biology for the female sex. It is a stylized representation of the goddess Venus's hand-mirror or an abstract symbol for the goddess: a circle with a small equilateral cross underneath.

The Venus symbol also represented femininity, and in ancient alchemy stood for copper. Alchemists constructed the symbol from a circle (representing spirit) above an equilateral cross (representing matter).(wikipedia.org)