Category Archives: Nature

How to Read a Scientific Paper

Standard
How to Read a Scientific Paper

When reading a Science Paper, we have to focus on identifying some basic informations. Therefore, we have to first understand how to identify each of them:

Background: Every paper presents the scenario in the previous literature that left a door open, leading to the present study. Usually, the authors start talking about it in order to address their own question.

Question: What is the question that authors designed the study to answer? Usually, it is presented right after presenting the previous literature.

Logic: What is the rationale of the experiment? In other words, why does it make sense to do the experiment in the way it was done?

Method: First thing to do is to identify the name of the Method. If you don’t know anything about the Method, you should google it before reading more about the Method… and identify:

  • Stimulus: what was presented to the subject
  • Task: what was the subject asked to do
  • Independent variable (IV): the variable that affects the DV (*)
  • Dependent variable (DV): the variable being measured; what is varying in the experiment that is affected by IV or correlated to the IV(*).

It is worth noting that most of the time the IV and DV are included in the paper title.

Results: What are the results of the experiment? Usually, they present many results but always emphasizing the result that is the most important. The results are very specific, and most of the times expressed in numbers, percentages, and statistical results. If you don’t know how to interpret them, skip to the conclusion… but keep in mind that is necessary to understand statistics in order to evaluate the liability of the paper.

Conclusion: How do the authors interpret the results?  What conclusion do they make from them?

(*) More about IV and DV: http://nces.ed.gov/nceskids/help/user_guide/graph/variables.asp

Advertisements

The Anatomy Years of Leonardo da Vinci [Os anos de anatomia de Leonardo da Vinci]

Standard
The skull sectioned (1489), one of Leonardo da Vinci's earliest anatomical studies. (Royal Collection Trust, Queen Elizabeth 2012)

The skull sectioned (1489), one of Leonardo da Vinci's earliest anatomical studies.
(Royal Collection Trust, Queen Elizabeth 2012)

Leonardo da Vinci has been primarily seen as a painter since the Renaissance but he would not recognize himself in such an image since his scientific studies were as important as his art. The amount of scientific observations made by Leonardo is still impressive but his difficulties reconciling his observations with the stablished beliefs prevented him from being able to bring his works to a conclusion.

Very little is known about his early life. Leonardo was an illegitimate son of a notary and a peasant girl, and he was born in 1452 in Tuscany, Italy. Although he taught himself Latin as an adult, he was never comfortable with the language that was the official one for scientific writings. His position outside the science field was indeed an obstacle for having access to contacts and resources although he portrayed himself as a disciple of experience and free of the ancient belief.

For Leonardo, painting was a scientific activity as well as his anatomy studies were paintings, and 87 of his anatomical studies are now going to be presented at the Queen’s Gallery in London – from May 4 to October 7 2012: Leonardo da VInci: Anatomist. Anatomy was not enough and he also tried to understand the human mind from one moment to another, expressing them in his paintings. At that time, human dissection was not banned (a papal bull of 1482 expressly permitted it) but Leonardo was a mere craftsman, and — then as now — a craftsman could not simply acquire a corpse and start dissecting it. Instead, Leonardo started with animal dissection, traditional belief and simple speculation. In 1489, he obtained a human skull and dissected that trying to find a relation between mind and body. He failed – but The Last Supper (1490) owes nothing either to the emotions or to the anatomical studies.

Later, as a celebrated artist, he probably had little difficult to have access to human corpses for his anatomical studies, and he had the chance to dissect an old man that he witnessed dying in a very peaceful way. So, he performed a dissection “to see the cause of so sweet a death”, and he attributed it to a narrowing of the coronary vessels, and wrote the first clear description of atherosclerosis in medical history.

There is no sign that Leonardo attempted to publish his research. He died in 1519 and left all his papers to his assistant Francesco Melzi, and although the anatomical studies were mentioned by all Leonardo’s early biographers, their content was barely comprehended. Unpublished, the studies were effectively lost to the world. Couple of decades later, anatomical exploration gained pace, and in 1543 Andreas Vesalius published an anatomical atlas named De humani corporis fabrica (On the fabric of the human body), a model of what Leonardo’s treatise could have been.

“Leonardo’s paintings changed the course of European art; but his anatomical investigations, the finest of their age, were essentially unknown. This exhibition will give an unprecedented chance to assess this most paradoxical of scientists” Leonardo’s anatomy years by Martin Clayton, Nature April 2012

The muscles of the shoulder and arm, and the bones of the foot (c.1510–11) (Royal Collection Trust, Queen Elizabeth 2012)

The muscles of the shoulder and arm, and the bones of the foot (c.1510–11)
(Royal Collection Trust, Queen Elizabeth 2012)

[Leonardo da Vinci foi visto principalmente como pintor desde o Renascimento, mas ele não se reconheceria nessa imagem visto que seus trabalhos científicos eram tão importantes quanto sua arte. A quantidade de observações científicas feitas por Leonardo ainda é impressionante, mas suas dificuldades em conciliar suas observações com as crenças as crenças da época o impediram de chegar a uma ou mais conclusões científicas.

Muito pouco se sabe sobre sua infância. Filho ilegítimo de um nobre e de uma camponesa, e ele nasceu em 1452 na Toscana, Itália. Embora ele tenha aprendido sozinho o latim quando adulto, nunca se sentiu confortável com a língua que era a oficial de escritos científicos. Sua posição fora do campo da ciência foi – de fato – um obstáculo para ter acesso aos contatos e recursos científico, embora ele tenha retratado a si mesmo como um discípulo de experiência e sem a crença da época.

Para Leonardo, a pintura era uma atividade científica, bem como os seus estudos de anatomia eram pinturas, e 87 de seus estudos anatômicos serão agora expostos na Queen’s Gallery de Londres – de 4 maio a 7 outubro 2012: Leonardo da VInci: Anatomist. O estudo de anatomia não o era suficiente e ele também tentou compreender a mente humana, de um momento para outro, incluindo-os em suas pinturas. Naquela época, a dissecção humana não era proibida (a bula papal de 1482 expressa a permissão), mas Leonardo foi um mero artesão, e – então como agora – um artesão não poderia simplesmente adquirir um cadáver e começar a dissecá-lo. Em vez disso, Leonardo começou com dissecação de animais, crença tradicional e simples especulação. Em 1489, ele ganhou um crânio humano e dissecou-o tentando encontrar uma relação entre mente e corpo. Ele falhou – mas A Última Ceia (1490) não deve nada, quer para as emoções ou para os estudos anatômicos.

Mais tarde, como um artista célebre, ele provavelmente teve pouca dificuldade para ter acesso a cadáveres humanos, e ele teve a oportunidade de dissecar um homem velho que testemunhou morrer de forma muito pacífica.Então, ele realizou uma dissecação “para ver a causa de uma morte tão doce”, e atribuiu-o a um estreitamento dos vasos coronários, e escreveu a primeira descrição clara da arteriosclerose na história da medicina.

Não há sinal de que Leonardo tentou publicar. Ele morreu em 1519 e deixou todos os seus estudos para seu assistente Francesco Melzi, e embora os estudos anatômicos tenham sido mencionados pelos primeiros biógrafos de Leonardo, seu conteúdo nunca foi totalmente compreendido. Não publicados, o mundo ficou privados de seus estudos anatômicos. Décadas posteriores, a exploração anatômica foi acelerada e, em 1543, Andreas Vesalius publicou um atlas anatômico chamado De Humani Corporis Fabrica (No Tecido do Corpo Humano), um modelo do que o trabalho de Leonardo poderia ter sido.

“Pinturas de Leonardo mudaram o curso da arte na Europa, mas suas investigações anatômicas, o melhor de seu tempo, eram essencialmente desconhecidos. Esta exposição dará uma oportunidade sem precedentes para avaliar o mais paradoxal dos cientistas” Leonardo’s anatomy years by Martin Clayton, Nature April 2012 ]