Meiosis celular y su relación con las alteraciones cromosómicas sexuales

LA MEIOSIS  es el proceso de division celular que atraviesan glandulas sexuales para producir los gametos, el óvulo y el espermatozoide. Durante este proceso, una célula dipolide realiza dos divisiones sucesivas con la capacidad de generar cuatro células hijas haploides los cuales poseen la mitad de cromosomas, es decir 23.  El proceso ocurre en dos etapas fundamentales MEIOSIS I y MEIOSIS II.

Este proceso tiene una importancia fundamental ya que mediante este se produce la recombinación genética, responsable de la variabilidad genética.

Sin embargo, hay veces en que producto de un error de la division celular de las gametas se producen ANOMALÍAS CROMOSÓMICAS correspondiente a un número anormal de cromosomas sexuales. En el momento de la fertilización, cuando se juntan un óvulo con un espermatozoide, se origina el número normal de cromosomas del feto, en humanos 46. Si durante la meiosis, un óvulo o espermatozoide tiene una anomalía cromosómica, el feto podrá recibir un cromosoma adicional "trisomía" o uno en falta "monosomía". 

Esta anomalía se debe a la no disnyuncion de los cromosomas sexuales. En los varones se podría producir espermatozoides ya sea con 22 autosomas y ningún  cromosoma sexual (espermatozoide "O")  o bien con dos cromosomas sexuales "XX", "YY" o "XY". Sin embargo en las mujeres, la no disnyunnsion produce óvulos "O" o "XX" en vez de un cromosoma X. 

El problema surge cuando los gametos normales se combinan con aquellos defectuosos, el número de autosomas es normal, pero el de los cromosomas sexuales es anormal, las mas comunes son:

•  XO --] Mujer: Síndrome de Turner
• XXX --] Mujer: Trisomía X
• XXY --] Varón: Síndrome de Klinefelter
• XYY --] Varón: Síndrome de Jacob
• YO--] Muere en estado embrionario, esto se debe a que los genes del cromosoma X son indispensable para la supervivencia, de manera que al no tenerlo el embarazo termina en aborto en una etapa temprana de su desarrollo.

Pink Floyd - The Wall

After watching in class the movie "Pink Floyd - The Wall", the teacher gave us a set of questions I will be answering below:

1. This portrays how society was educated based on equality as what is socially accepted regardless of their identity, where everyone is enclosed to follow a standard stereotype. Masks in both situations represent people as faceless individuals which are part of a machine and are all somehow the same. They were shaped under certain ideals and cannot be set free so as to think by themselves
   
2. The riot scene was all in the boy's mind; he was imagining what it would be like to step aside from that stereotype that everyone was pressured to form part of. The scene begins with the teacher mocking the kid's imagination and creativity, in other words we can say that being different was not accepted. Therefore the kid afterwards begins to imagine what would it be like to break the order and stand out of the stereotype. However, the scene comes back to the class at the end, to show that they are still being under a strict control, and expressing their feeling is not acceptable. 
3. The movie portrays a tough and strict kind of education. We can see how the teacher follow a certain educational structure which should be respected by the children and if they didn't they were punished. Moreover every actitude a student had that showed him different to the rest was considered as a weakness and used to embarrass him.
4. The movie deals with various social institutions which are the government, education and the family. As regards the government we can mention it to be what controls everything by the education. They are who decide what what we should learn in order to grew up following their beliefs. The government’s purpose is to making us follow a same stereotype for they to keep the control of everything, and control means power. Therefore we can say that what the government looks after is power, which is just accessible if they force us to think like them. On the other hand, the family is the other institution portrayed in the movie, we can see how Pink losses his father after the wall and all he has left was his mother, yet she seems not to be present in his life. We can say that family is important for us, it represents who we will become, since parents are who we looked after when we are kids. This can be shown in the scene were he wears with his father uniform imitating him. This is why we can say that the movie presents to us different social institutions which have the same purpose, since these are what will guide us during our childhood to grow up and will determine our future.
   
5. The phrase “We, in Argentina, often rely on education to solve most of our social problems. We blame education, or the lack of it, for many of them” is something that you always listen here, and we constantly repeat too. However, we think that what the film what is trying show us, is that aggressive and repressive style of teaching children, where students are blame of thinking different. 
6. In the movie education is shown as the base for control. It portrays how the society is build from the education teaching the younger generation the way they have to act and think. So if they teach in the institutions a way of behaving and show them what they consider to be good or bad, then in the future everyone would follow the same beliefs and hence they have the control of everyone.
7. In the fresh scene we can appreciate a group of double-hammer marching perfectly in order. This whole metaphoric scene what is trying to teach us is how education control us to be a “perfect” person without any error, and with a same style of life and that the meaning of being different means to be a wrong person. 
   
8. The children falling into the meat grinder is a visual metaphor that represents how education kills every different thought from what the government and schools wants, leaving only a human body, a robot that only express and repeat one idea. What education do to children is burning their brains and every thing that is different. 
9. In the Cambridge dictionary the wall is defined as a structure made of brick or stone that divides different areas. In the Pink Floyd film the wall represents is how society is divided between the good persons and the bad ones, where education is a key point from these division. Another way of seeing this powerful concept this that “we are just another brick in the wall”, where every human being represents a brick in that wall, representing only one thing, the same thing, the same idea, hiding our differences,and making it impossible to us to build our own wall and creating our wall, full of knowledge and diferents ideas.
   

Work done toghether with Tomas Busquets and Sebastian Varisto

Nous avons visité l'Alliance Française

   Le Mardi 17 Mai nous sommes allés à L'Alliance française. L'Alliance était extraordinaire et ancienne à l'extérieur mais très moderne à l'intérieur.

Nous alions à la médiathèque, nous faisons des activités avec les livres, les CD, les DVD et les VD. Il y avait beaucoup de matériels anciennes. La médiathèque était grande et magnifique avec beaucoup technologies.

Après nous avons visité une salle de classe pour regarder les vidéos éducatives avec la coordinatrice. On a eu une classe de compréhension de l´orale et on a répondu des questions.

Plus tard, nous avons obtenu un souvenir avec un stylo et un magazine. Enfin, nous sommes retournés au collège. 

Bref, dans l'Alliance, nous avons passé une tranquille, et belle journée oú nos avons eu la possibilité de apprendre un peut plus de la culture Française.

Salle de Classe

Médiathèque 

L'extérieur de l'Alliance

Eyewitness Accounts

    An eyewitness, is someone who actually sees some act, occurrence, or event and can give a first hand description of it. Eyewitness accounts are mostly considered by the people as a more reliable and credible source than hearsay accounts. This is due to the fact that for being a first-hand account, meaning that after all the person was there and saw what actually happened, is more trustworthy than second-hand accounts, which often distort the event while this is being told or re-told. 

However, it should be stated that eyewitness accounts can be questioned and often considered unreliable and inaccurate, since the witness might give a wrong story due to many reasons. Observation is based on the five senses, therefore, if one of this is impaired the accuracy would be affected, hence the credibility of an eyewitness will be lessened. Moreover, there are different factors which might affect and eyewitness. Firstly, the context of where and when the observation takes place will affect what people see and hear, for example if its night or day, the weather condition, the distance from the event, if there is any obstruction, etc. Secondly, the perception, expectation and memory would also influence and observer, the memory reconstructs an observation, then this would be based on its pre-existing experience, knowledge, expectation and belief. Thirdly, the point of view of the eyewitness will affect his observation, people are not objective and neutral, consequently their observations would tend to be distorted due to their biased and prejudice view. Lastly, the prior knowledge and expertise will also affected, the more you know about a certain topic or event the better you can shape your account, and so you add more credibility to an account. 

CAE writing

   Why is it difficult to know he truth about historical events?

    It is often claimed that we would never get to know the real events from our past. In this essay I will argue on how descriptions of historical events vary according to cultural and political influence.

   Firstly, we can state to be true that a similar situation might be pictured from different points of view depending a persons´s background, for instance, would the native Americans share opinion with the Europeans about the colonization of America? Definitely not. Natives will surely tell another story,they would speak about murder and fear rather than a civilized cultural exchange. Mostly while talking about a past situation we will approach the topic through a biased view about it and depending on our own world view. 

   Secondly, we have the political influence. Not only only do politicians create history, but they also benefit from it. The way in which incidents take place has a great impact on them. Therefore, they might retell history based on their outright-lies in order to benefit. Hence, we can argue that politicians will be one-sided or distort the information due to their own vested interest.

   Taking everything into consideration, we can say that how past events are told will be influenced mainly on the interests of politics and by people´s beliefs and values. To my mind, our past is and, unfortunately, will always be uncertain since it is difficult for people to leave their ideals a side and be objective.

Wrongful conviction and eye witness accounts

Case: MARVIN ANDERSON

In December 2001, Marvin Lamont Anderson became the ninety-ninth person in the United States to be exonerated due to post conviction DNA testing.

Anderson was convicted in 1982 of a rape he didn't commit and sentenced to 210 years in prison. He was released on parole after 15 years, but he continued to fight to overturn his wrongful conviction. It would be five more years before DNA testing obtained with the help of the Innocence Project finally proved his innocence.

The victim was a woman who was raped on July 1982 by a black man. The assailant beat her, threatened her with a gun, raped her, and sodomized her. After she reported the crime, a police officer singled out Marvin Anderson as a suspect because the perpetrator had told the victim that he "had a white girl," and Marvin Anderson was the only black man the officer knew who lived with a white woman. Sine he had no criminal record, the police had to investigate his personal data. Afterwards, they showed the victim many possible pictures of the aggressor; among them, Anderson´s one. The victim identified him between the pictures as well as in in the lineup whose picture was in the original photo array shown to the victim. Anderson’s trial counsel offered an alibi defense including his white girlfriend. Despite the fact of Anderson’s lack of previous conflicts with the law and that from the very beginning the community became aware that it was John Otis Lincoln a more likely suspect, a all-white jury convicted Anderson on all counts, even though the owner of bicycle which was identified to be used by the assailant reported it as robbed by Lincoln some hours before the rape. 

In 1988, John Otis Lincoln came forward and took up the guilt and the following consequences in the hearing held in August, in order to free Anderson from the case. Even so, the judge refused to vacate the conviction, claiming Lincoln to be a liar. 

For Anderson´s luck, fifteen years after his conviction, a DNA test prove his innocence and he was set free.

Mitigación... ¿para mi bien o para el de todos?

Se define al término mitigar, bajo una perspectiva ambiental, como “el conjunto de medidas que podemos tomar para contrarrestar o minimizar los impactos ambientales negativos que pudieran tener una intervención antrópica” , por lo que podemos decir que su propósito será atenuar los daños potenciales sobre la vida causados por un cierto evento. ¿Pero a quién le adjudicamos esta responsabilidad?

Desde siempre, como sociedad (científicos, arquitectos, el gobierno, matemáticos, físicos, biólogos, ambientalistas, entre otros) hemos cooperado en conjunto con el fin de evaluar y plantear estrategias para satisfacer y promover nuestro desarrollo humano y así poder adaptarnos a las condiciones del lugar en donde vivimos. Tales como el diseño de construcciones resistentes a terremotos, condiciones climáticas muy frías, calurosas o lluviosas, etc. Por otro lado, también buscan alcanzar un desarrollo sustentable, es decir que genere el menor impacto en el ambiente, como la reducción de emisión de gases de efecto invernadero, la reforestación, y conservación de bosques. A estas las denominamos como estrategias de mitigación ya que tienen como objetivo reducir el impacto que cada día generamos en el ecosistema.

Hoy es día es ya un hábito escuchar a la población reclamarle al gobierno una mayor participación a la hora de buscar resoluciones y/o estrategias para asegurar el desarrollo y la mitigación necesaria para contribuir a la conservación y a su vez a la protección tanto de nuestros bienes, de los recursos naturales y de nuestras propias vidas. Sin embargo es necesario como individuos y sociedad reflexionemos sobre la importancia de nuestra responsabilidad. 

Cada uno de nosotros debemos ser parte, debemos trabajar juntos y de manera individual para el beneficio de uno y de todos, porque juntos somos más, y si cada uno colabora el cambio será cada vez más visible y notorio. Hay ciertas acciones, algunas sencillas y otras tal vez no, pero son acciones que cada uno de nosotros puede realizar y ayudar a mitigar el daño que generamos.Como es el caso disminuir el uso del automóvil, el hacer uso del transporte público o caminar en trayectos cortos colabora notablemente en la reducción de dióxido de carbono y otros gases que se emiten a la atmósfera; debemos ser conscientes de las tres R, reducir, reusar y reciclar; utilizar elementos de bajo consumo; no derrochar el agua; evaluar las condiciones de los lugares donde se construye; y también apoyar el uso de energías alternativas, son algunas de las medidas que cada uno de nosotros podemos realizar para cooperar. 

Porque es cierto que somos “uno para todos, y todos para uno”, todos podemos aportar parte de nosotros para así asegurar las condiciones de vida nuestras y de las futuras generaciones y proteger al medio ambiente.