Analysis of Attack Tree Methodology

Analysis of Attack Tree Methodology Information technology (IT) Security has become more and more important today when as e-commerce is becoming increasingly popular. People in developed countries like America and throughout European countries have been exposed to online trading for a long time; this trend is also taking off in developing countries in other parts of the world. Besides its importance toward business activities, IT security also plays a pivotal role in protecting individuals, organizations assets, which are actually parts of the business operations. Variety methods of securing business have been developed and implemented successfully. Attack Trees is one of those. Not only in Information Technology, Attack Trees is also applicable to security problems in a wide range of fields including: telecommunications, health care, finance, critical infrastructure, aerospace, intelligence and defense. To secure your business against impending risks, you first need to define all kinds of possible risks and pathways that those risks might be realized. Acknowledging risks and how they might happen, you will be able to develop measures to fight against or mitigate them. This is also what Attack Trees helps clarify. Attack Trees is a formal, convenient way to methodically categorize the different ways (how the risks happen) in which a system can be attacked[1] (risks). Attack trees are a graphical and mathematical construct used to Identify potential hostile activities that pose the greatest risk to the defender; Determine effective (and cost effective) strategies for reducing the defenders risk to an acceptable level; Describe the potential interactions between the adversary and the defender; Provide a communication mechanism for security analysts; Capture what is known (facts) and believed (assumptions) about the system and its adversaries, and store the information in a form that can subsequently be retrieved and understood by others[2] Attack tree models are graphical diagrams representing the choices and goals available to an attacker. They are represented in a tree structure, in which the root node of the tree is the global goal of an attacker and leaf nodes are different ways of achieving that goal. In an attack tree, children of the root node are refinements of the global goal, and leaf nodes represent attacks that can no longer be refined. A refinement can be conjunctive (AND) or disjunctive (OR). Figure 1 shows an example of an attack tree with the goal of the attacker is to obtain a free lunch[3]. The tree lists three possible ways to reach this goal. Lower levels in the tree explain how these sub-goals are refined. The arc connecting the children nodes expresses that this is a conjunctive (AND) refinement, which means that all sub-goals have to be fulfilled. Refinements without such a connecting arc are disjunctive (OR), expressing that satisfying one sub-goal suffices The strength of the attack tree methodology lies in the fact that its graphical, structured tree notation is easy to understand to practitioners, yet also promising for tool builders and theoreticians attempting to partially automate the threat analysis process. More and more research papers have been used attack trees in modeling security threat of information system. Over the last year, over 15,000 articles on GoogleÂÂ ® Scholar[4] have been used the attack tree technique in some way. The way this technique is used now is usually by assigning different kinds of values to the leaf nodes (for example, possible and impossible, expansive and inexpensive, cost to attack, probability of success of a given attack, etc.) then propagating node values up the tree following some rules. Based on that calculation, people can make some statements about attacks, for example, what is the cheapest low-risk attack or most likely non-intrusive attack[5]. In retrospect personal experiences, we notice that what we have done in the past and until now are closely related to what is presented in Attack Trees model, although back by that time, we were not exposed to concept of Attack Trees, but the approach is basically the same. It was when we worked on a project and had to define all possible risks/threats that might happen and how we can take mitigate actions against those risks. The only thing that we had not paid enough attention to, and was actually very important thing, was how all those risks might happen. Failing to do this costs us a lot later on when the risk did happen in a way that we had not thought of, so did not develop appropriate cause of actions and we were passively react to it. It was when we were developing an online testing system to help students prepare for entrance exam to universities[6]. We would have a strong team of excellent teachers from many famous schools build the test content; and have a team of people t o import those tests, including answers (multiple choice format), into the system. We conducted training for importing team. (Also, the importing work did take a lot of time so we could not talk all the teachers into it). Things went well until the day we actually launched the Beta version. We had volunteers, who were actual pupils, do the test; it was nothing better for them to take free tests and receive free feedbacks. But when it came to result announce and feedbacks were given to those pupils, everything was just totally wrong; many of student answers, which were actually correct, were marked incorrect and the must-be-correct answers given by the system were actually incorrect. Recalling that single day, it was a BIG shame on us, the team who worked on the project. We had a person head of quality control who would make sure that all the tests designed, including questions and answers, are without mistakes. We were very strict on that. We also had a head of training department w ho will make sure that our collaborators, who performed importing job, do their job carefully and without mistakes. Random test were taken before we launched the first version and things were all going very well. We developed risk monitoring blocks and figure 2 is shown as an example. For a risk that the test is invalidate, we clarified three possible reasons: design problem, importing problem and system problem. The reasons are then tracked further along blocks which are colored accordingly. So to prevent or mitigate the risk, we only need to make sure that our teacher quality is excellent, our training and importing job are done beautifully and our system will not malfunction. But we only did to the extent that, for example, as long as our collaborators work diligently and carefully, mistakes would largely be avoided. Later on, we found out the root of the problem was that one of our collaborator was person from our main competitor and he purposely destroyed our system by changing all correct answers just a night before the free testing event. This was the thing that we had never thought of. We did not think that we had problem right from the collaborators recruitment and that this might had been one of many possible ways that can invalidate our test bank. Until then did we know that what we called in general collaborators quality is not limited to the fact that whether they were capable of understanding and doing the job, but also including their working ethic. Consequently, we were left with everything beginning from scratch; all teachers work was carefully rechecked because we did not know right away what exactly caused the problem. Almost all the imported work was deleted and restarted. If we had been able to clarify this possibility, though small, we would have developed action appropriate enough to prevent it, such as lock the system and deny any access before we launched the first version, this would have saved us money and time and prestige as well. We finally were able to offer a running version but it surely had cost us much more resources.[7] From our personal experience, we see that Attack Trees model is a very useful tool to help organizations in threat detection and appropriate mitigating action development. The model will have important and positive impact on organization business operation in that it help name all possible risks and specific pathways that those risks might become real. From that, it helps determine effective and cost effective strategies to reduce risks to an acceptable level. Organizations should adopt Attack Trees model to secure themselves from any uncertainties that may happen. References Attack trees: Modeling security threats. Dr. Dobbs journal; Schneider (2005). Attack Trees Analysis, Terrance Ingoldsby on January 16, 2009 http://redteamjournal.com/2009/01/attack-tree-analysis/ Mauw, S., Oostdijk, M. (2005) Foundations of Attack Trees Information Security and Cryptology-ICISC 2005 Springer http://scholar.google.com/scholar?hl=enq=attack+trees+information+systemas_sdt=2000as_ylo=2009as_vis=0 Edge, K. (2007) The Use of Attack and Protection Trees to Analyze Security for an Online Banking System. HICSS 07: Proceedings of the 40th Annual Hawaii International Conference on System Sciences. This is how universities in my country recruit prospective students, they do not base on applications but base on result of actual tests, which are held by the Ministry of Education annually for all participants Our initial project result to date http://hocmai.vn/

Relationships in Good Country People, by Flannery OConnor Essay

   Flannery O'Connor's "Good Country People" is a story told through the examination of the relationships between the four main characters. All of the characters have distinct feelings about the others, from misunderstanding to contempt. Both Joy-Hulga, the protagonist, and Manley Pointer, the antagonist, are multi-faceted characters. While all of the characters have different levels of complexity, Joy-Hulga and Manley Pointer are the deepest and the ones with the most obvious facades. The first character we encounter is Mrs. Freeman. She is the wife of Mrs. Hopewell's tenant farmer. She is a very outspoken woman, and "she [can] never be brought to admit herself wrong on any point" (O'Connor 180). Mrs. Freeman is a gossip; she is nosy and she "ha[s] a special fondness for the details of secret infections, hidden deformities, assaults upon children" (O'Connor 183). Mrs. Freeman wants to be an authority on everyone else's personal business. She is never shy of sharing the details of her daughters' lives with Mrs. Hopewell. I get the impression that she tells anyone that she meets the intimate details of the lives of Glynese, Carramae, Mrs. Hopewell, and Joy-Hulga. Being a poor tenant farmer's wife, her only weapon is her speech (Enjoiras 36). In order to compete with Mrs. Hopewell, she must be constantly on the look-out for ways to subtly one-up her in the course of their conversations. Asals describes their conversations as "hackneyed one-upmanship" (99). For example, the way they speak to each other one rnorning goes like this: "Everybody is different," Mrs. Hopewell said. "Yes, most people is," Mrs. Freeman said. "It takes all kinds to make the world." "I always said it did myself.... ...f the story proves it. The facades they put on are as essential to "Good Country People" as the mindless conversations between Mrs. Freeman and Mrs. Hopewell. The relationships between these four characters are what make "Good Country People" such a literary success.       Works Cited Asals, Frederick. Flannery O'Connor : The Imagination of Extremity. University of Georgia Press; Reissue edition. Athens, Georgia, 2007. Enjolras, Laurence. Flannery O'Connor's Characters. New York: University Press of America, Inc., 1998. Feeley, Kathleen, S.S.N.D. Flannery O'Connor: Voice of the Peacock. New York: Fordham University Press; 2 edition, 2010. O'Connor, Flannery. The Complete Stories. Thirty-seventh printing. New York: Noonday Press, 1994. Whitt, Margaret Earley. Understanding Flannery O'Connor. University of South Carolina Press, 1997.

Gone with the wind Essay

1.Give a summary of the book. Include the plot, the rising conflict and its climax and so on. 2.Give the character that you identify most? Why? 3.What is the setting of the story and how does it affect the story? What would happen if the story was set in another time or setting? 4.What are the major conflicts in this story? How would have Jesus reacted to one of the conflicts in the story? Gone With the Wind Gone with the wind is one of best novel I have ever read. It is also the greatest love story ever written. It is set during the American civil war (1861) in which the Southern states (the Confederacy) tried to free themselves from the northern states. The main character of this story was the beautiful Scarlett O’Hara. Her father, Gerald O’Hara was an old Irishman who owned a big cotton plantation named Tara. He also owned tens of slaves who worked for him. Scarlett’s mother was Ellen O’Hara and she was one of the kindest and most respected ladies in the county. All her life, Scarlett O’Hara wanted to be like her mother Ellen. The main O’Haras neighbors included the Wilkeses, the Tarletons, and the Calverts. As she was the most beautiful girl in the whole county, she had many beaux compared to any girl in the county. Almost all the boys were in the county were in love with her. But the Tarleton twins, Brent and Stuart, whom Scarlett liked hanging out with were twice madly in love with her compared to any other boys. But the problem was that Scarlett didn’t love them. She  was madly in love with Ashley Wilkes, her neighbor. She believed that Ashley Wilkes and her were meant to be together and neither the coming civil war nor the Tarleton twins were going to change that. But then, Scarlett learnt from the twins that the love of her life Ashley was going to marry his cousin Melanie Hamilton. She could hardly believe this and depression suddenly took the better part of her. Luckily, the Wilkeses organized a barbecue in which they were going to announce Ashley Wilkes engagement to his cousin. Scarlett planned to tell Ashley that she loved him and he would propose to her and forget about his cousin Melanie. and then maybe they would elope. But at the Wilkes’ barbecue, her plan didn’t succeed. Ashley told her that he loved his cousin Melanie because they were alike blood wise and they were alike in many other ways. Now, since they didn’t want to be heard by others as they were having their secret talk they decided to do it in the library. Unfortunately after they had finished their talk and Ashley had left the library, Scarlett started crying. Then from the back of the library, a man appeared, with an evil smile on his face. Scarlett knew that he had been listening to their conversation. His name was Rhett Butler and Scarlett told him that he was no gentleman and she was surprised to hear that she was no lady. To make Ashley Wilkes feel jealous, Scarlett married the timid and shy Charles Hamilton who was Melanie brother. Every boy who was in love with Scarlett was furious and even the Tarletons twins swore to kill Charles. Then the war started, and before all the men went to the war, Scarlett married Charles and Melanie married Ashley on the same wedding and day. Within two weeks of her marriage, Scarlett was already a widow as Charles Hamilton died in the war due pneumonia. But this didn’t worry Scarlett as she didn’t love Charles. But she was sad as Ashley had married another chick and he had gone with her. So everybody confused this, and thought that she was mourning for her husband’s death Charles. Scarlett left her home Tara to Atlanta as her parents thought that a change  of scene would reduce her stress and depression. She was happy because she moving to the Hamilton house where Melanie used to live and also, the half of the house was hers. Through Melanie maybe she would learn how Ashley was doing through the mail he sent to her. For a second time, Scarlett met Rhett Butler who was by now a blockader, as the Yankees were not allowing the Confederates to trade with other countries with nations through the Eastern United States port search New York. Gone with the wind, is a rather big book and hence hard to summarize, but this is what happened next briefly. The Yankees took over Atlanta and Scarlett had to go back to Tara. Then after the Yankees had taken over the south, the former confederate had to pay high taxes for their homes. Scarlett didn’t want to lose Tara she didn’t have the money to pay the taxes. To get the money, she married Frank Kennedy, her sister beau and got the money. But then, Frank died in KKK and Scarlett was left a widow again. Scarlett was tired of waiting for Ashley’s love, so she married Rhett Butler who loved her so much although he didn’t tell her. But she didn’t love him. Then, Melanie Wilkes, died during childbirth and Scarlett thought that she had a shot her love Ashley. She was surprised to know that Ashley didn’t love her but only loved his wife Melanie who now dead. She was so sad and it didn’t take her long to figure out that the only person who ever loved her was Rhett Butler. But when she went to him, she was surprised to know that he was tired of waiting for her love and also he had just lost his beloved daughter Bonnie whom he had substituted with Scarlett as the most important thing in his heart. So there was Scarlett. All life she had loved a man whom didn’t love her. She had loved Ashley Wilkes, and thrice she destroyed her marriages for his sakes, all in the name of love. A love that didn’t exist, a love that she created herself and never got t enjoy her creation not even a bit, what a waste it was. Margaret Mitchel was a genius author and I was so sorry when I read gone with the wind for the second time, I will never be able to read it for as the second time, only a third, maybe. 2. Gone with the wind is rather a large and complex book with different character that is worth identifying and naming. But the main characters that I mostly identify are Scarlett O’Hara the beautiful, cunning, crafty and the farsighted, Rhett Butler the arrogant and the wealthy. Also Melanie and Ashley were wildly mentioned in the story but not as much as Scarlett and Rhett Butler . 2b. I identify most with Scarlett O’ Hara and Rhett Butler as they have something I believe I have. Both Scarlett are hard workers. They both make ends meet to achieve what they want. Also to, they both don’t cares, which I find fascinating, because sometimes, I feel like the biggest don’t care in the world. You might not understand what I am talking about, here is a look of both the characters from the book. vScarlett O’Hara: ‘you miss, are no lady) said Rhett Butler to Scarlett. (Pg. 122) ‘I am a monster of selfishness’ said Scarlett O’Hara. (Pg. 584). She is the main character overall. Almost every beau in the county is in love with her at the beginning and every girl hate her for that Although she is madly in love with Ashley Wilkes who doesn’t really lover her, she marries Charles Hamilton just to make Ashley Wilkes feel jealous. She then becomes a widow within two weeks after Charles is killed in the war (pg129). Being a widow doesn’t mean she a mourner because she didn’t really love Charles. All she cares about is the love of her life Ashley Wilkes. Scarlett faces major difficulties when the Yankees make their way to Atlanta and she has to escape back to her farm Tara. With only one horse, and a mechanically bogus carriage and three children, sick Melanie and herself, she travels ten of miles until she riches Tara. (pg. 383) at Tara she finds that her heroic mother figure is dead and her father has gone crazy. Other struggles of Scarlett include when the Yankees tries to kick her family out of Tara due to unpaid tax and she had to leave for Atlanta to look for money from the rich Rhett Butler only to find that he is in prison. She secretly schemes to cheat and marry her sister Suellen beaux, Frank Kennedy, so that she can get the tax money from him. She succeeds and becomes Mrs. Kennedy. She really bullies Frank Kennedy and make him look less than man especially when she buy and starts managing the sawmills. Fortunately for her, Frank is shot  during a KKK meeting. After being widow for a while, she marries Rhett Butler who loved her so much and gave anything that he wanted. But the only problem is, she couldn’t love him because she was still in love with Ashley Wilkes. By the time she realizes Ashley couldn’t love her, and that she was in love with Rhett Butler, it was too late because Rhett was tired of waiting for her love and he had just lost his most favorite daughter. Her favorite phrase was ‘God Nightgown’ vRhett Butler: ‘You are no gentleman† said Scarlett to Rhett. (pg.122). Nobody including his family could receive Rhett Butler to their homes before the civil war. He was an outcast in his hometown Charleston because he disgraced a girl and refused to marry. But the thing was, Rhett Butler didn’t care what other thought of him. Other people’s opinion didn’t move him. When he saw Scarlett at the Wilkes’ barbecue, he instantly fell in love with her and told himself the day he was going to marry her it would be his lucky day. During the civil war, the Yankees did not allow the Confederacy to trade with the Europeans or any other part of the world through the port of New York City. It was know as the famous Blockade. Then Rhett Butler a wise and corrupted man; made a pact with the Yankees, in that they would sell him goods of all kind. He then go to the confederate, tell them how hard it was to run the blockade, which he actually didn’t and sell his goods to them at double price. The somehow people found out it. 3. Gone with the wind would not have been such a big success if it weren’t set during the American civil war. Don’t get me wrong here. I am not trying to imply that the book is a historical record of the civil war. It is a love story. At the before the civil war, we meet Stuart and Brent Tarleton who are both madly in love with Scarlett and who believe that one of them is going to marry her (pg. 4). We also meet Ashley Wilkes who is planning to marry his cousin Melanie Wilkes. The O’Hara sisters, Suellen who is in love with Frank Kennedy, Careen who is in love with Brent Tarleton who by the way is in love with Scarlett. There many other young people that I will not mention who had sweet hearts and were planning to get married. Then came the news that the war was going to start with a few days and that all the young men available were to leave and join the army. This meant the young  sweethearts were either to get married before the men left for the war or there could wait until the war was over. Well some couple got married other decided to wait. The example I have in mind is when Scarlett O’Hara married Charles Hamilton but when Charles left for the war, he died within less than two weeks. (Pg. 129) If Charles happened to live, then we would have no story because Scarlett wouldn’t have the freedom to marry other men, which she did and made the story deserve to be read at a sitting. The setting made the story more real, entertaining and worth reading. It was a love story because young girls got to lose their sweethearts in the war and then the author would show us how they got to survive, get other lovers and so on. if the story was set on other setting such as the modern times, let say the year 2003 instead of 1861-5, it wouldn’t be such a successful love story because nothing of much significant has happened that affects young sweethearts apart from STDs which don’t mostly affect true and faithful lovers. If the story were set maybe in the middle ages or the renaissance, it would have been quite a boring book to read. Most people don’t want to read how the plague affected young lovers, and there wasn’t romantic love didn’t exists as wildly as it did in the 19th century. But on the other it would be a more interesting love story if it was set during the time of chivalry and brave knights and so on. Sir Walter Scott’s Ivanhoe was a huge success as a romantic story and so was the Alexander Dumas’s The three Musketeer set during 1665 during the reign of Louis the just or the 8th. But none can, or is near the Margaret Mitchel Gone with the wind! What a pity. 4. This is a huge book with almost tens of conflicts and I shall try to get the major conflicts. vThey is an inner conflict between the Tarletons twins, as they are both deeply in love with Scarlett, but they are not sure among them whom she is going to choose among them, then they are surprised out of their wits when she chooses the timid and shy Charles Hamilton vThere is a general conflict between the union and the Confederacy as the Union refuses to recognize it as a free state. This leads to the civil war, which is the general setting of the great novel. vAshley has an inner conflict whether he loves Scarlett or not which leads to the biggest conflict in the book which is: vThere are other smaller conflicts, which I would take hours and tens of pages to name and analyze, so I will just, move to the major conflict. vScarlett is madly in love with Ashley Wilkes who finds it difficult to make it clear to her that he is only in love with his cousin Melanie and is only attracted to Scarlett because of her beauty (pg.118). This end up causing much problem to Scarlett because she end up marrying men she didn’t love. Married Frank Kennedy just to save Tara form being taken away by the Yankees because of the taxes, where by the way Ashley and his family were taking refuge. She also marries Rhett Butler whom she didn’t love because she was tired of waiting for Ashley’s love. And then, Ashley’s wife Melanie dies during childbirth and Scarlett know that she has her chance to marry love of her life, but she gets the surprise of her lifetime, v†Ã¢â‚¬ËœWhat you have gone through†¦Oh Ashley, you should have known, years ago, that you loved her and not me! Why didn’t you! Everything would have been so different, so-Oh you should have and not kept me dangling with all your talk about honor and sacrifice! If you told me long me, years ago, I’d have–It would have killed me but I would have it somehow. But you wait till now, till Melly dying, to find it out and now it is too late to do anything†¦You should have seen so clearly that you wanted me like–like Rhett that Watling woman!'† said Scarlett to Ashley (pg.1002) vJesus Reaction!–Throughout the book, we see that Scarlett is driven to do most of the thing she does because of the love she has for Ashley. She marries Charles to make Ashley feel jealous, she marries Frank Kennedy to save Tara where Ashley was residing. She even makes him a manager of one of her mills so that she can stay closer to him. Ashley on the other is attracted physically to Scarlett but he isn’t sure whether he she for her. Both of this people are married. What they did, according to Jesus, they Committed Adultery! Matthew 5:27-29 says (Jesus) ‘but now I tell you: anyone  who looks at a woman and wants to posses to her is guilty of committing adultery with her in his heart!’ So, both Scarlett and Ashley committed adultery and according to Jesus, Matthew 5:29-30 ‘so if you right eye causes you to sin, take it out and throw it away!†¦It is better than you to lose apart of your body than to go to hell!’ How I get is, Jesus would have advised to stop what they, to tell to show them that they were committing sins in the eyes of our God the creator. He then would have given time to redeem himself and if it didn’t work, he would declare them sinners and St. Paul said that the reward of sins is death! And so did Jesus, but he wouldn’t be that harsh, he is and was Jesus Christ!

Types Of Cancer Of The Uterus, Uterine Sarcomas And...

There are two main types of cancer of the uterus, uterine sarcomas and endometrial carcinomas. Endometrium cancer begins when the tissues of the inner lining of the uterus (endometrium) begin to grow out of control.1 There are many subtypes of endometrial cancer based on the histology of the cells. Endometrial cancer is furthermore, graded based on how much the cancer forms and glands that have the similar morphology of healthy and normal endometrium glands.2 Endometrial Cancer primarily affects woman of postmenopausal age and some of the risk factors include, things that affect hormone levels, like taking estrogen after menopause, birth control pills, or tamoxifen; the number of menstrual cycles (over a lifetime), pregnancy, obesity, certain ovarian tumors, and polycystic ovarian syndrome, use of an intrauterine device, age, diet and exercise, diabetes, family history (having close relatives with endometrial or colorectal cancer, having been diagnosed with breast or ovarian cancer i n the past, having been diagnosed with endometrial hyperplasia in the past and treatment with radiation therapy to the pelvis to treat another cancer. 3 The four basic treatments for endometrial cancer are surgery, radiation therapy, hormonal therapy and chemotherapy.4 Expanding on treatment, there is a growing body of evidence that suggests the anti-diabetic class, biguanides, may have effective anti-cancer properties against endometrial cancer. 2 The three drugs included in this class areShow MoreRelatedThe Cause of Endometrial Cancer Essay1540 Words   |  7 PagesUterine cancer, sometimes referred to as endometrial cancer, is the most commonly diagnosed gynecologic cancer in the United States (ACS, 2013; CDC, 2012). Each year about 45,000 women get uterine cancer and about 8,400 women die from it (CDC, 2012). It is a cancer caused by abnormal cells growing in the lining of the uterus, or endometrium (ACS, 2013; CDC, 2012). The two major types of uterine cancer are adenocarcinoma and sarcoma. Adenocarcinoma develops from the endometrium, which make upRead MoreMaagang Pagbubuntis Ng Mga Kabataan9395 Words   |  38 Pages     Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   EFFECTS OF TERATOGENS ON A FETUS: 1)  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  depends on the: a)  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  strength of the teratogen ï‚ §Ã¯â€š  Ã¯â€š  Ã‚  ex. Radiation – in small amount sun rays it causes no damage, but in large amount like in cancer treatment, serious fetal defects or death can occur. b)  Ã‚  Ã‚  Ã‚  Ã‚  timing of teratogen ï‚ §Ã¯â€š  Ã¯â€š  before implantation = zygote is aborted or is unaffected ï‚ §Ã¯â€š  Ã¯â€š  organogenesis – vulnerable to injury ï‚ §Ã¯â€š  Ã¯â€š  Last trimester – decreased harm (except syphilis and toxoplasmosis