How calcium is absorbed in the body Essay Example for Free

How calcium is absorbed in the body Essay Calcium in the diet of a teenager is actively absorbed in the small intestine and transferred into the intestinal capillaries. Describe the route this calcium would follow to end up in the upper arm. Describe in detail the role of calcium at the neuromuscular junction as well as its role in the mechanism of muscle contraction and relaxation of the triceps. Considering the function of calcium in bone growth, explain in detail how the humerus would grow in length. Calcium in the diet of a teenager is absorbed in the small intestine and transferred to the intestinal capillaries. It diffuses into the bloodstream through the gastric vein into the hepatic vein and then through the common iliac vein into the superior/inferior vena cava that brings the blood into the right atrium of the heart. The sinoatrial node which is located in the right atrial wall, would send an electrical impulse through the heart, causing it to contract. This would then trigger the AV node (which is located between the septum between two atria) to contract as well. When the AV node contracts it sends an impulse through the AV bundle and into the purkinje fibers (which in return causes the entire heart to contract). After going through the right atrium, when the heart contracts it opens up the tricuspid valve, therefore pushing the calcium into the right ventricle. When the heart contracts again (SA node contracts again through AV bundle and purkinje fibers) it causes the pulmonary semilunar valve to open and enters the pulmonary trunk and pulmonary arteries which then brings the blood into the lungs. Then it goes through a systemic loop (the tissue capillaries of the lungs) , which takes the now oxygenated blood and returns to the heart via the pulmonary veins from the lungs. Then from the pulmonary veins the blood enters the left atrium (SA node will contract, causing AV node to contract, sending impulse through the AV bundle, ending at the purkinje fibers) and calcium forces through the bicuspid valve, and into the left ventricle. Then the heart contracts, and (SA node/AV node/AV bundle/purkinje fibers) causing contraction and blood travels through the aortic valve and then into the aorta. From the aorta, the calcium in the blood goes into the right and left subclavian artery and branches down to the axillary artery, and then towards the bra chial artery. From the brachial artery, the oxygenated blood containing calcium in it, goes to the muscles of the upper arm (the brachii muscles) and gives nutrients to the tissue cells. Calcium plays an important role in muscle contraction. Firstly, an action potential arriving at the acon triggers the release of the neurotransmitter called acetylcholine (ACH) at the neuromuscular junction. The acetylcholine (ACH) binds with the muscle receptor and sodium ions (Na+) are released, which triggers the action potential in the muscle cell. The action potential transmits through the sarcolemma. The calcium (Ca+) ions are then released from the sarcoplasmic reticulum. The calcium ions bind with troponin (making it change shape) which makes the troponin release tropomyosin. The myosin then binds to the actin. With the hydrolysis of ATP the myosin head changes shape and a cross-bridge is formed causing the muscle cell to contract. This cycle repeats itself until the contraction is done, or when there is nor more calcium or ATP energy. Once the triceps muscle is relaxed then the calcium gets back into the sarcoplasmic reticulum. During relaxation of muscle cells, the level of calcium in sarcoplasm is low and the troponin holds the tropomyosin in position to block myosin-binding sites on actin. During contraction of the muscle cells, a muscle action potential opens calcium channels in the sarcoplasmic reticulum and the calcium flows into the cytosol. The growth of bones can happen through two different types of ossification which include: intramembranous ossification and endochondral ossification. The process for the growth of a long bone like the humerus, the process of endochondral ossification is used. This takes place on the epiphyseal plate (made from remaining hyaline cartilage) in the metaphysis area of the bone. There are four zones on the epiphyseal plate: a) the resting zone which contains the chondrocytes, b) the zone of proliferation where the chondrocytes divide and push the resting cartilage outwards, c) the zone of hypertrophic cartilage where the chondrocytes enlarge and lengthen the diaphysis, d) Zone of calcification- where dead chondrocytes and new one matrix is created. At the end of the growth period, the epiphyseal plates  are completely ossified and the epiphyseal plates close around the age from 18-25. The epiphyseal plates then become the epiphyseal lines. The calcium is a necessary dietary requirement for proper bone growth, development in the body, and to prevent bone deterioration or an example of a disease called osteoporosis.

Delaying Childbearing: Why it is Important to Have Children While in Co

Like many other women, I was raised in a family that repetitively told me that I needed to finish school before thinking about getting married, and definitely before having kids. This made sense when I became an adult, why not put all my focus into my schooling. Yet, for me that would mean that I would be in my early thirties when I finished school. This has become the norm for women to marry and have children in there 30s, then in years past, where they were in their early to mid-twenties. After completing my first bachelor’s degree, I got engaged; I was in a perfect place, and I was not going to hold off just so I could finish school. Now that I have been married for two years, successfully working and going to school, starting a family is important to me. If I were to follow what my parents told me, from this day, I would still have to wait 4-5 more years to finish school, and then start that family. Even though having kids in college could keep your from completing a degr ee, you should have children in college because delaying childbearing could affect fertility and the likelihood of pregnancy complications. College is perceived as a time for young adults to have fun, and having children before or during college would provide an obstacle of completing a college education. Four million college students have children, which is roughly 25 percent of all enrolled college students (Nelson, Froehner, and Gault 1). Although this is a large number, many students would prefer to focus on themselves. Today women face the dilemma of if they even would want to have children. Focuses on getting a degree, and starting a career is ever so important for many women to create their lives on. Waiting until you are settled in your career puts ... ...n in school has many problems, as well as advantages. First, the obvious reason is that having kids in college is a financial burden, along with the stresses of maintaining family life with college life. Secondly, many students that do have children while in school, unfortunately, do not finish their degree. Works Cited Balasch, Juan, and Eduard Gratacà ³s. "Delayed Childbearing: Effects On Fertility And The Outcome Of Pregnancy." Fetal Diagnosis & Therapy 29.4 (2011): 263-273. EBSCO MegaFILE. Web. 20 Apr. 2014. Cnattingius, Sven, et al. "Delayed childbearing and risk of adverse perinatal outcome: a population-based study." Jama 268.7 (1992): 886-890. Nelson, Bethany, Meghan Froehner, and Barbara Gault. College Students with Children Are Common and Face Many Challenges in Completing Higher Education. Mar: Institute For Women's Policy Research, Mar. 2013. PDF.

Contrasting both Kant and Aristotle’s views Essay

Aristotelian philosophy, some two thousand three hundred years old, is perhaps one of the most influential philosophies in history. After being preserved by Arab scholars during the fall of Rome, the teachings of Aristotle were found by Christians during the dark ages. His works, including Nichomachean Ethics, were of great influence to many Christian philosophers during medieval times, but soon philosophies began to shift, marking the conception of the Enlightenment. Philosophy took a drastic shift from predominantly substantive reason to procedural views, markedly seen in works by philosophers St. Augustine, Rene Descartes, and quite notably Immanuel Kant. By comparing the views shared by Aristotle in Nichomachean Ethics, and Kant’s Groundwork of the Metaphysics of Morals it is possible to better understand the shift from substantive to procedural reasoning. Although Aristotelian philosophy and logic shares some common ground with the writings of Kant, Groundwork of the Metaphysics of Morals marks a shift from society and substantive thinking toward the self and procedural reason. Kant believes that each living organism serves a purpose. For example, the highest purpose of a honey bee is undoubtedly to produce honey. Much in the same sense, Kant feels that because humans alone are given the ability to reason that the highest purpose of humanity is to use reason. (Groundwork, Ch. 1, Ln. 50-80) Aristotle would agree with this statement but uses a different logic. Aristotle sees an intrinsic good within every action, as well a hierarchy of goods and actions. Using the logic that any action partaken for the purpose of some greater cause is secondary to the greater cause, Aristotle reasons that for humans, the act of reasoning is of the greatest â€Å"good† because all other actions exist only to maintain the ability to reason. (NE, Bk.1 Pg. 1-2) Between these two philosophies, the purpose of human reason differs based on what each philosopher believes to be the function of humanity within society. Aristotle states that because happiness is the ultimate goal of nearly all human actions (especially within what he considers one of the most important realms of humanity: political science) the purpose of  humanity, and thus human reason, is to find happiness. (NE, Bk.1 Pg. 4) Kant, on the other hand, feeling that to succumb to the needs of the body and desires (what he calls heteronomy) is selfish, feels that it is the responsibility of humanity to use its reason to act out of â€Å"good will.† (Groundwork, Ch. 1, Ln. 3-5) Exemplifying the procedural nature of Kant’s logic, Kant feels that it is the duty of humanity to act only out of good will by using reason to determine what Kant calls the categorical imperative. Kant defines the categorical imperative as an act of good will which is preformed with no considera tion to the ends, or consequences of an action. (Groundwork, Ch. 2, Ln. 280-300) In the world of Aristotelian philosophy, the only way to truly attain the end goal of happiness is to be virtuous. (NE, Bk.1 Pg. 4) To define virtue Aristotle looks to society’s views of an individual. People praise a brave man for being brave and strong man for his ability to run quickly or lift great objects. (NE, Bk.1 Pg. 4) Because of the importance of society within Aristotle’s thinking, he feels that for a person to truly be virtuous, society must perceive desirable characteristics within that person and recognize those characteristics through praise. To illustrate and explain his organization of virtues and what is required of them, Aristotle uses the final paragraph of book one in Nicomachean Ethics: â€Å"Virtue too is distinguished into kinds in accordance with this difference; for we say that some of the virtues are intellectual and others moral, philosophic wisdom and understanding and practical wisdom being intellectual, liberality and temperance moral. For in speaking about a man’s character we do not say that he is wise or has understanding but that he is good-tempered or temperate; yet we praise the wise man also with respect to his state of mind; and of states of mind we call those which merit praise virtues.† -Aristotle, (NE, Book 1, Final Paragraph) Unlike Aristotle, Kant finds goodness not in the views of society, but instead finds goodness by turning inward and looking individual within one’s self and their exertion of good will. Kant feels that to express good will, an individual must use what he calls a priori reason. (Groundwork, Ch. 2,  Ln. 280-300) A priori reason requires that the individual ignores subjective influences like consequences and circumstances. By focusing on objective means like morality and reason Kant suggests that the individual attempting to exert good will should act in a way that he or she would consider a moral maxim (categorical imperative). Kant thinks we must ignore the norms of society and the way society functions and act only using a priori reason because society inherently cannot function in an a priori fashion. This is because society takes into account its own needs, desires, and calculates the consequences of its own actions while placing all of these things over pure reason and good will. By taking into consideration circumstances and consequences society fails to create universal moral law and thus contradicts its own reasoning because the actions of society are not appropriate in all situations and circumstances. (Groundwork, Ch. 2, Ln. 580-590) Should a man in need of money to buy food borrow money from a lending institution knowing that he will not be able to pay that institution back? Kant argues that that man should not, for if his decision were to become universal law and every man or woman were to borrow money without the intention of paying it back than lending institutions would fail. (Groundwork, Ch. 2, Ln. 590-605) Aristotle, believing that society can teach its citizens to be virtuous (and thus happy), finds that virtues are not found intrinsically within each individual. For a person to be virtuous he must be born to a respectable family, for he were not born into respect then he would never be viewed by society with the same esteem as others. He must also not have any major disfigurations, for these too would lead to a lower value within society. Assuming these conditions are met, the individual may then begin to practice virtuous actions, because through habituation virtuous actions can become the nature of that individual, and that through practice an individual may grow to perform virtuous acts not out of desire to be virtuous, but because he simply enjoys the virtuous acts. Only if the individual finds pleasure in performing virtuous actions may that person be seen as virtuous within the eyes of society, for if pleasure is the end goal of humanity, then surely the enjoyment of virtuous a cts is worthy of praise from society. After outlining and discussing both Kant and Aristotle’s views on the purpose of humanity, its role within society and the moral and ethical consequences to those roles it is clear that Kant’s thinking is representative of enlightenment thinking. Before the Enlightenment Aristotle’s views were widely accepted. During this time it was customary that each person function in a manner accepted by society. Ethics and morality were dictated by social norms. The purpose of reason was seen as the pursuit of pleasure, and through virtue and the practice of virtuous actions reason could allow the individual to attain the end goal of life: happiness. In response to Aristotle’s logic, a shift in thought occurs. This shift, called the Enlightenment, is represented by the belief that only pure reason can lead to true morality. The consequences of this belief is that individuals no longer focused on the norms within society to dictate morality, but to look within themselves to use their own reasoning to dictate what should and should not be done. An example of this thinking can be found in Kant’s beliefs about a priori reason and the categorical imperative. By ignoring consequences within society, as well as the ends attained by each possible action Kant feels each individual can find true moral goodness through pure reason. This type of procedural logic is representative of the moral and ethical â€Å"turn inward† which exemplifies Kant’s philosophy as well as the revolutionary shift thinking that became the basis of the Enlightenment.

Islamic Law - Free Essay Example

Sample details Pages: 7 Words: 2141 Downloads: 1 Date added: 2017/06/26 Category Law Essay Type Narrative essay Tags: Act Essay Islam Essay Did you like this example? Paternity under Islamic Law The paternity of a child can be established through marriage, acknowledgement and evidence under the Islamic law in Malaysia. Paternity of a child should be established in order to determine his or her status as a legitimate child or an illegitimate child. Thus, when a child is born, it is important that his legitimacy is assured so that his rights such as right to maintenance, custody and inheritance can be established. Don’t waste time! Our writers will create an original "Islamic Law" essay for you Create order The provision for legitimacy of a child can be found in the Islamic Family Law (Federal Territories) Act 1984 (IFLA). First of all, the paternity of a child can be determined through marriage. All elements of marriage must be fulfilled and most importantly, the marriage must be valid. There must also be consummation of marriage for legitimacy of a child to be fully established. The paternity of a child should not be determined through the resemblance of physical features between the husband and the child. The Shafii school of thoughts and s 110 of IFLA[1] provided that where a child is born to a woman who is married to her husband after six months from the date of marriage or within 4 years after the dissolution of marriage and the mother having not remarried, the paternity of the child is belongs to the husband. The paternity of a child will not be established in the man if the child is born within the six months period of the marriage. The husband may either by way of lian to disclaim the child if he strongly believes that the child does not belong to him or he may allege that the child is his and but is not as the result of fornication. The jurists of the Islamic Jurisprudence interpreted the six months period from their understanding based on surah 46: 15 and surah 31:14 of the Holy Quran. Surah 46:15 stated that à ¢Ã¢â€š ¬Ã…“à ¢Ã¢â€š ¬Ã‚ ¦the carrying of the child to his weaning is a period of thirty monthsà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚  while surah 31:14 stated that à ¢Ã¢â€š ¬Ã…“à ¢Ã¢â€š ¬Ã‚ ¦in travail upon travail did his mother bear him, and in years twain was his weaningà ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚  Hence, by subtracting the two years which is equivalent to 24 months as stated in the second verse from 30 months which is stated in the first verse, the jurists get 6 months which is the minimum period for a baby to be delivered out from his or her motherà ¢Ã¢â€š ¬Ã¢â€ž ¢s womb. In Salim v Masiah,[2] the respondent and appellant were married on 6 October 1968 and divorced on 19 November 1968. The child, Maimon was subsequently born on 2 June 1969. The respondent claimed for the maintenance for her child while the appellants alleged that the respondent was already pregnant at the time of marriage. The Kadi gave judgment in favour of the wife and stated that the child was born after six months after their marriage. The appeal was dismissed subsequently. In instances where a woman remarries and subsequently gives birth to a child within the period of six months of remarriage, the childà ¢Ã¢â€š ¬Ã¢â€ž ¢s paternity is as of the first husband. The child will only be ascribed to the second husband if the woman gives birth to the child after the period of six months from the time of consummate with the second husband. Where the husband had accused the wife of fornication or zina, the husband must bring in 4 witnesses and if he fails to do so, he must take the oaths as prescribed in surah 24:6-7 as stated in the Q uran. If the wife denied the accusation, she must also take the oaths as prescribed in surah 24:8-9 of the Quran. As a result of such oath, the woman will not be subjected to zina punishment and the child will be legally fatherless. The child will have no right to inherit any estate of the father and vice versa. S 111[3] stated that the paternity of the child shall not be affiliated in the man where a child is born more than 4 years after the dissolution of marriage unless he or his heirs alleged that the child belongs to him. S 112[4] described that where a woman, not having remarried, upon completion of her iddah period and subsequently give birth to a child, the paternity of the child should not be affiliated to her husband unless the child was born less than four years from the date of the termination of their marriage. S113[5] provide the child which is born as a result of syubhah intercourse will not be considered as illegitimate child but instead the childà ¢Ã¢â€š ¬Ã¢â €ž ¢s paternity shall be affiliated to the man. Syubhah intercourse is the sexual intercourse between a man and a woman whom both of them believe that they are lawfully married and lawfully declared as husband and wife which is later proven otherwise. The child shall remain legitimate if the woman had give birth to the child between the periods of six months to four years after the intercourse. Secondly, the paternity of a child may also be determined through acknowledgement. S114[6] provides that when a man had either expressly or impliedly acknowledges another as his lawful child, the paternity of the child shall be established in the man. However, there are 7 conditions that need to be fulfilled by the man in order to declare that the child indeed belong to him. First, there should be no other people that had established the childà ¢Ã¢â€š ¬Ã¢â€ž ¢s paternity in him. This means that there should be no one else other than him that claims the child was theirs. Second, the age of the man and the child are such that filial relationship is possible between them. For example, there should be a difference of at least 15 years of age gap between the father and the child. If the age gap is narrow, it is possible that the child will disrespect the father or treated him as his brother. Thus, bigger large gap is important to establish the respect and filial between the father and child. Third, if the child is of discreet age of understanding the nature and surrounding circumstance, he should has acquiesced or agree with the acknowledgement. The child must agree that the man who intended to acknowledge him as his lawful child to be his legal father for the rest of the childà ¢Ã¢â€š ¬Ã¢â€ž ¢s life. Fourth, the man and the mother of the child could have been lawfully joined in marriage when it was begotten. There shall not be any proof that there were no lawful marriage between the man and the mother of the child which will affect the presumption of legitimacy o f the child. Fifth, the acknowledgment should not be only merely son-ship but that the child is his legitimate child which was a result of the consummation of marriage between the man and the mother of the child. He must not just merely acknowledge the existence of the child but also the kinship between both of them. Sixth, the man must be a competent person and have the legal capacity to enter into a contract. Any contract entered by a minor shall be deem void. Under the Shafii school of thoughts, a minority age for a male is below 15 years old. Thus, a 14 years old boy does not have the capacity to enter into the marriage contract. Seventh, the man who acknowledges must have the true intention of affirming the status of legitimacy of the child or acknowledgement of the child is definite to be the child of his body. In other words, he must have the confidence that the child is reproduced from his sperm and the ovum of the childà ¢Ã¢â€š ¬Ã¢â€ž ¢s mother and the child is part of him. S115[7] provides that the presumption of paternity through acknowledgement can be rebutted in a few ways. First is by the disclaimer on the part of the person acknowledged. The presumption may also be rebutted where it is proven that the proximity of age between the man and the child would render the filial relationship impossible. This usually happens when the age gap between the man and the child is too narrow. Other than that, the presumption may also be rebutted where it is proven that the child in fact belongs to other person or the child is the result of consummation marriage of some other person with the mother of the child. It is also rebuttable where there is proof that man who intended to acknowledge the child could not possibly be the lawful husband of the mother of the child at the time when the child could have been conceived. S116[8] provides acknowledgment by a woman in iddah shall not ascribe the paternity of the child to her husband unless this acknowl edgment is affirmed by him or by evidence. S117[9] provided that the acknowledgment of the child who acknowledged another as his parent shall constitute a valid relationship of kinship in condition the filial relationship is possible between them. S118[10] provided that acknowledgment other than as a child or parent shall not affect any other person except he affirms the acknowledgement. By virtue of S119[11], the acknowledgement shall become irrevocable once it has been made in respect of paternity or relationship. Lastly, paternity of a child can be determined through evidence. This happens when the husband is in doubt on the paternity of the child which was delivered by his wife when he was away for a short period of time. The wife may bring two females as evidence to prove her innocence. However, as the society has kept developing, the type of evidence to be proof also evolved. Most people prefer to use DNA test in proving the paternity of the child. DNA test is more accurate in proving the genetic relationship between the biological father and the child. There are cases where newborn babies are mix-up in hospitals and DNA test has easily proof the paternity of the child. This may also serve as strong evidence when there are two people acknowledging the paternity of the child. [1] Section 110 of Islamic Family Law (Federal Territories) Act 1984 states that where a child is born to a woman who is married to a man more than six qamariah months from the date of the marriage or within four qamariah years after dissolution of the marriage either by the death of the man or by divorce, the woman not having remarried, the nasab or paternity of the child is established in the man, but the man may, by way of lià ¢Ã¢â€š ¬Ã¢â€ž ¢an or imprecation, disavow or disclaim the child before the court. [2] (1976) 2 JH 296 [3] Section 111 of the Islamic Family Law (Federal Territories) Act 1984 states that where a child is born more than four qamariah years after the dissolution of the marriage either by the death of the man or by divorce, the paternity of the child shall not be established in the man unless he or any of his heirs asserts that the child is his issue. [4] Section 112 of the Islamic Family Law (Federal Territories) Act 1984 states that where a woma n, not having remarried, makes a declaration that the period of à ¢Ã¢â€š ¬Ã‹Å"iddah has been completed, whether the period is for death or divorce, and she is subsequently delivered of a child, the paternity of the child shall not be ascribed to her husband unless the child was born less than four qamariah years from the date of the dissolution of the marriage either by the death of the husband or by divorce. [5] Section 113 of the Islamic Family Law (Federal Territories) Act 1984 states that where a man has syubhah sexual intercourse with a woman, and she is subsequently delivered of a child between the period of six qamariah months to four qamariah years after the intercourse, the paternity of the child be ascribed to the man. [6] Section 114 of the Islamic Family Law (Federal Territories) Act 1984 [7] Section 115 of the Islamic Family Law (Federal Territories) Act 1984 [8] Section 116 of the Islamic Family Law (Federal Territories) Act 1984 states that where the ackn owledgor is a woman who is married or who is observing the à ¢Ã¢â€š ¬Ã‹Å"iddah, the paternity of the person acknowledged shall not be ascribed to her husband unless her acknowledgment is confirmed by him or by evidence. [9] Section 117 of Islamic Family Law (Federal Territories) Act 1984 states that where a person acknowledges another as his father or mother, the acknowledgement, if assented to or confirmed by the acknowledgee,, whether during the lifetime or after the decease of the acknowledgor, shall constitute a valid relationship, in so far as the parties themselves are concerned, provided that the ages of the acknowledgor and the acknowledge are such that filial relationship is possible between them. [10] Section 118 of Islamic Family Law (Federal Territories) Act 1984 states that where a person acknowledges another as a relation other than as a son, mother, or father, the acknowledgment shall not affect any other person unless that other person confirms the acknowledge ment. [11] Section 119 of Islamic Family Law (Federal Territories) Act 1984

Pregnancy and Humans in Space

No matter where they live, many people eventually end up having kids, even in some of the most out-of-the-way spots on the planet. But, will they be able to live and work in space and have children? Or on the Moon? Or on Mars? Humans being humans, they will very likely try. Whether they succeed or not depends on a lot of factors. One vision of Mars habitats that will provide shelter for astronauts as they learn to explore the planet. Eventually, they could be raising families on the Red Planet, in more extensive habitats that may well be underground. What will those children be like?. NASA As humans prepare for a future off Earth, mission planners are finding answers to a number of questions about long-term space residency. One of the most perplexing is Can women get pregnant in space? Its a fair one to ask since the future of humans in space depends on our ability to reproduce out there. Is Pregnancy Possible in Space? The technical answer to that question is: yes, its possible to become pregnant in space. Theres nothing known about being in space that would prevent egg and sperm from uniting to make a baby. Of course, a woman and her partner need to be able to actually have  sex in space  in order to for those cells to get together in the first place. Additionally,  both she and her partner must  be fertile. Cycles infertility can be checked, and the mom and dad could then choose the right time to make that space baby. However, theres more required than doing the deed. It turns out there are significant other hurdles that stand in the way of having what it takes to make a baby and then  remaining pregnant once fertilization takes place. Barriers to Child-bearing in Space The primary problems with becoming and remaining pregnant in space are radiation and low-gravity environments. Its important to understand both.  Ã‚   The Moon has practically no atmosphere and no way to filter out harmful radiation. Humans living there would face some radiation danger from solar particles and cosmic rays. This could have a profound effect on a couples ability to start a family.   NASA Radiation can affect a mans sperm count, rendering him infertile, possibly permanently. It can also harm a developing fetus. Radiation hazards exist here on Earth, too, as anyone who has taken a medical x-ray or who works in a high-radiation environment knows. Its why both men and women are usually supplied with protective aprons when they get x-rays or other diagnostic work. The idea is to keep stray radiation from interfering with egg and sperm production. Once an embryo is created, its subject to the same radiation dangers as the mother. Conditions that Could Interfere with Pregnancy Lets say that conception happens after a couple gets together on the space station or during a trip to Mars or even after they land on the Red Planet. The radiation environment in space (or on Mars) is severe enough that it would prevent cells in the fetus from replicating. Thus, no baby would be brought to term.   Mars has a thicker atmosphere than the Moon, but it still is not enough to shield humans from radiation. This is another place where humans could face difficulties conceiving and birthing children. Credit:NASA/JPL-Caltech/MSSS In addition to the high radiation, astronauts live and work in very low-gravity environments. The exact effects are still being studied in detail on lab animals (such as rats). However, its very clear that a gravity environment is needed for proper bone development and growth. When astronaut Scott Kelly (and others) spent long periods on the International Space Station,  they showed significant changes in their health. Similar issues could affect a developing fetus. Such atrophy is why astronauts have to exercise in space regularly in order to prevent muscle atrophy and loss of bone mass. A growing embryo or fetus could be permanently altered, right down to the DNA. Solutions to the Radiation Problem Clearly, if people are to venture out into space on a more permanent basis (like extended trips to Mars) radiation hazards need to be minimized, not just for the adults but for any possible children born on the trips.  But how to do that? Astronauts taking extended trips into space will be on ships that are likely not to provide the heaviest radiation shielding. Once they get to Mars, for example, theyll be subjected to a lot of radiation on the surface that is not stopped by the thin atmosphere. Also, the lower gravity on Mars (and on the Moon, for those who migrate there), will be an issue.   The Orion crew capsule (shown here in water recovery testing) is a typical crew-carrying spacecraft that is shielded to protect astronauts from most radiation. Special precautions and materials must be used to protect crew members. Future spacecraft will need similar protective environments. NASA   So if permanent residencies are ever going to exist on Mars or the Moon, like those proposed by Dr. Mae Jemison for the  Hundred-year Starship, then better shielding technology would have to be developed. Since NASA is already thinking of solutions to these problems, its likely that radiation will cease to become as big a threat as it is now. Overcoming the Gravity Problem The problem of a lower gravity environment may be more difficult to overcome if humans are to successfully reproduce in space. Life in low gravity affects a number of body systems, including muscular development and eyesight. So, it may be necessary to supply an artificial gravity environment in space to mimic what humans evolved to expect here on Earth. The good news is there are some spacecraft designs in the pipeline, like the Nautilus-X, that employ artificial gravity designs. These use centrifuges that would allow for at least a partial gravity environment on part of the ship. Anyone who has ridden a ride such as the Mission Space experience at Disney Worlds EPCOT center has felt the gravitational effects that a centrifuge can supply.   The problem with such designs is that they cant yet replicate a full gravity environment, and even then occupants would be constrained to one part of the ship located in the centrifuge. This would be difficult to manage. Further exacerbating the problem is fact that the spacecraft needs to land. So what do people do once on the ground in a low-gravity environment on a place like Mars? The Future in Space: No Kids in Space Yet Ultimately, the long-term solution to the problem is the development of anti-gravity technology. Such devices are still a long way off. However, if spaceship technology could somehow manipulate gravity then it would create an environment where a woman could carry a fetus to term. Until that is a possibility, humans going to space currently are very likely using birth control to prevent stillbirths and miscarriages. If they are having sex, its a well-kept secret. But there have been no known pregnancies in space.   Nonetheless, humans will have to face a future that includes space-born and Mars- or Moon-born children. These people will be perfectly adapted to their homes, and oddly enough—the Earth environment will be alien to them. It will certainly be a very brave and interesting new period in human history!   Edited and updated by Carolyn Collins Petersen.

War Breaking Out On American Soil - 1470 Words

Today it is hard to imagine war breaking out on American soil. Though war has most definitely not ceased to exist as a constant worry in our minds, most Americans do not have to fear a stray bomb to drop into the yard. The Civil War, though, had exactly that kind of effect on the American population, both of the Union and the Confederacy. Civilians often found themselves at the mercy of either army, in some cases both, and were forced to choose a side even if they wanted no part in the war. As the films Shenandoah (1965) and Ride with the Devil (1999) portray, for many people the war invaded their lives, and forced them to take matters into their own hands against the evil-doing soldiers as irregular troops waging guerilla warfare. Other times, as the film Pharoah’s Army (1995) depicts, helpless civilian families and their homesteads came under occupation by the opposing side. When neighbors begin warring, nobody could escape the crossfire and people found themselves entangled in the war whether they wanted to take part or not. Primary documents from Major Problems in the Civil War and Reconstruction, edited by Michael Perman, tend to support the films’ points on the depiction of the role of the civilians, such as the anonymous letter from the plain folk protesting the burden of the war from February of 1863. Shenandoah begins with a vision of the nineteenth century dream of idyllic American life. Farmer Charlie Anderson is happy and satisfied on his peaceful tract ofShow MoreRelatedTerrorism Essay1030 Words   |  5 Pagescarried out on U.S. soil. Much time has passed since then and the United States has changed in the succeeding years. Billions more than before, are now going into defense funds. American citizens have lost many conveniences as well as bits and pieces of privacy. Many Americans have even added many words to their vocabulary. Words like Al-Queda and Anthrax are thrown around in everyday conversation. To most these things are unde rstandable, they were changes necessary to insure Americans safety. Read MoreEssay about United States Involvement in The Second World War (WWII)615 Words   |  3 Pages World War II nbsp;nbsp;nbsp;nbsp;nbsp;As totalitarian sates emerged into power, the United States got involved with World War II to help control these groups and to promote democracy in the European theatre of the world. The party with the most power at the time was the Nazi Party, led by Adolf Hitler. This socialist party was led by a powerful dictator who broke away from the League of Nations and began to conquer vast amounts of territory at a fast rate. The United States wanted to leaveRead MoreThe Long Way Home By David Laskin848 Words   |  4 PagesThe author of â€Å"The Long Way Home: An American Journey from Ellis Island to the Great War† is David Laskin. 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Article Summary And Critique Free Essays

Abstract This paper is going to summarise an articles that relate to environmental management and ecological modeling. It will also include a critique of the article in order to ascertain whether it has logical arguments.The critique will also involve an assessment of whether there was conclusive evidence in the article. We will write a custom essay sample on Article Summary And Critique or any similar topic only for you Order Now In this paper, additional literature will be used in order to make personal opinions on the conclusions made by the authors of this article. Summary: Hutchins, M. G., 2012. What impact might mitigation of diffuse nitrate pollution have on river water quality in a rural catchment The article entitled â€Å"What impact might mitigation of diffuse nitrate pollution have on river water quality in a rural catchment?† by Michael Hutchins, studied the role played by nitrate loads in freshwater. The investigator carried out the study by evaluating how phytoplankton growth is affected by nutrient and light concentration. On one hand, the assessment of nutrients concentration was done by the measurement of annual mean concentration sourced from periodic regulatory monitoring. On the other hand, the effect of light was assessed using data sourced from solar radiation and sediment monitoring data. The investigator went further and assessed areas in the river under study that had sufficient calm water that could facilitate the growth of phytoplankton. This was done using hydraulic data collected from river network model applications. The researcher then went further and developed an analysis of the effect of the changes on land management in the nitrate concentrat ions in the river. This was carried out using estimations from NALTRACES, a nitrate model. An analysis using NALTRACES concluded that as much as agriculture contributes to increased levels of nitrates in the river water, its effect on the growth and concentration of phytoplankton is negligible. The study also found out that the growth of phytoplankton is regulated by the amount of sunlight that is able to infiltrate the water. In fact, areas that allow maximum light infiltration into the water promote extensive growth of Phytoplankton even if the levels of nitrates in the water are very low. Therefore, the investigation concluded that nitrate concentration is not one of the conditions that determine the growth of phytoplankton in the river water. The investigation concluded that developing a means of regulating the amount of light reaching the water is an effective way of regulating the growth of phytoplankton. It also suggested the establishment of a riparian tree cover as one of the ways that can be used in the regulation of light availability in the river water. Data was gathered and analyzed using a variety of simple modeling approaches to arrive at the conclusion that an effective way of mitigating phytoplankton growth is by minimizing illumination on the water surface. Critique The article by Hutchins is researched well, and the conclusions developed from the findings are well founded and backed by a good number of previous investigations. The conclusions are well founded because they are derived from the collected data. In addition, the conclusions are achieved after the collected data is critically analyzed and evaluated. The methodology applied in the investigation is effective enough to provide an explanation to the research issue. This is because it involves the collection of primary data as well as secondary data (Hutchins, 2012), which assists in explaining terms used in this research. The investigation applied a correlation analysis of nutrient level and phytoplankton growth, resulting to the development of a conclusion that had enough evidences that backed it. The evidence was derived from the data in the correlation analysis. In fact, the data used in the research acted as evidence for the conclusions made. Furthermore, data regarding sunlight ill umination and phytoplankton growth was used in the development of a sound analysis. From this analysis, it was concluded that it is one main factor that if controlled, the growth of phytoplankton can be fully regulated. On examining the sources used in this review, we notice that all sources are academic and written by well-known authors and published in credible journals. In fact, most of the studies referenced in the investigation were conducted between the years 2003 and 2012. Therefore, the sources cited in this article are the latest with respect to information portrayed in the article. However, the article has provided a stand that contradicts many recent investigations that link phytoplankton bloom to increased nutrient levels in water. Xu et al (2010) proposes an approach of regulating phytoplankton bloom in Lake Taihu that basically involves an approach aimed at lowering the lake waters nutritional levels. From their study, it was evident that phytoplankton bloom in the lake is directly associated with increased leaching of nutrients into the lake waters. On the other hand, Hutchins (2012) argues that nutrient levels have no form of association with phytoplankton bloom. This assertion is not founded since effects of human activities lead to unnatural forms of occasions. The sun is always constant, and its effects with relation to phytoplankton bloom are directly proportional to the levels of nutrients available in the waters to effect growth. As much as his conclusion links the reduction of illumination in the river as an approach towards managing the growth of phytoplankton, the application of this approach is quite limited and time consuming. In most cases, it might take several years to manage the problem by developing a means of regulating sunlight. According to a study by Lewis and Wurtsbaugh (2008), the phytoplankton growth limiting effect of nitrates is not universal. It is common in waters found in the high altitude tropic regions, which are not the case of the location of the river analysed in the study. The author also mentions phosphorus as a mineral that has no effect on the concentration of Phytoplankton; this stand contradicts a study by Sylvan and his colleagues (2006), which provided an inverse proportionality of the concentration of phosphorus to the concentration of phytoplankton. Therefore, the assumption adopted by Hutchins (2012), in his investigation required a deeper clarification on the approach adopted on arriving at the conclusion of delinking mineral concentrations to phytoplankton growth in the river. For the case of this river, I think a study that specifically analyses the extent to which nutrients affect the growth of phytoplankton is the best approach that will provide practical and applicable findings and recommendations. An in-depth analysis of the impacts of each nutrient to the growth of phytoplankton is necessary. Furthermore, this article is limited in its approach to developing a recommendation that aims at limiting the sunlight accessing the water in the river. As much as he assures the reader of the effectiveness of that approach, it is less viable due to several issues, including cost and time factor. In conclusion, as much as this article enriches the available level of understanding on management of Phytoplankton, its limitation in terms of applicability of the findings limits the effectiveness of the study with relation to the topic of the paper. References Hutchins, M. G., 2012. What impact might mitigation of diffuse nitrate pollution have on river water quality in a rural catchmentJournal of Environmental Management, 109, 19-26. Retrieved from http://dx.doi.org/10.1016/j.jenvman.2012.04.045 Lewis, W. M., Wurtsbaugh A. W., 2008. Control of lacustrine phytoplankton by nutrients: Erosion of the phosphorus paradigm. Internat. Rev. Hydrobiol. 93, 446–465. Retrieved from http://ciresweb.colorado.edu/limnology/pubs/pdfs/Pub190.pdf Sylvan, J. B., Dortch Q.,Nelson, D.M.,MaierbrownA.F.,Morrison W., Ammerman, J. W., 2006. Phosphorus limits phytoplankton growth on the Louisiana shelf during the period of hypoxia formation. Environ. Sci. Technol. 40, 7548–7553. Retrieved from http://www.researchgate.net/publication/6548676_Phosphorus_limits_phytoplankton_growth_on_the_Louisiana_shelf_during_the_period_of_hypoxia_formation/file/d912f51017f64c452b.pdf Xu, H., Paerl, H.W., Qin B., Zhu G., Gao, G., 2010. Nitrogen and phosphorus inputs control phytoplankton growth in eutrophic Lake Taihu, China, Limnol. Oceanogr., 55(1), 420–432. Retrieved from http://www.jlakes.org/web/Xu%20et%20al.-LO2010.pdf How to cite Article Summary And Critique, Essay examples