Tuesday, February 06, 2007

Vitamina D reduz riscos de cancro colorrectal e da mama

A vitamina D reduz até 50 por cento o risco de cancro da mama e mais de 66 por cento o de contrair cancro colorrectal, segundo dois estudos hoje publicados nos Estados Unidos.


A investigação sobre o impacto da vitamina D no cancro da mama, divulgada na edição electrónica do Journal of Steroid Biochemistry and Molecular Biology, baseia-se no acompanhamento de 1.750 pessoas submetidas a doses diferentes da vitamina.

Estes investigadores do Centro Moores sobre cancro da Universidade da Cali fórnia em San Diego mostraram que indivíduos com concentração mais elevada de vi tamina D no sangue (52 nanogramas por mililitro de sangue) correm menos riscos d e desenvolver cancro da mama.

"Pode reduzir-se em 50 por cento o risco de cancro da mama através do cons umo diário de 2.000 unidades internacionais de vitamina D (ou seja uma concentra ção de 46 nanogramas por mililitros de sangue), acompanhado de 10 a 15 minutos d e exposição solar por dia", afirma Cedric Garland, um dos autores do estudo.

Paralelamente, o American Journal of Preventive Medicine publicou hoje os resultados de uma análise semelhante feita com 1.448 pessoas para medir os efeit os da vitamina D no risco de cancro colorrectal.

"Elevando a dose de vitamina D absorvida diariamente de 13 para 34 naogram as por mililitro, a incidência do cancro colorrectal seria reduzida a metade", d eclarou um dos autores do estudo, Edward Gorham.

"O risco baixa dois terços com uma concentração de 46 nanogramas/ml", acre scentou, precisando que este nível pode ser atingido com complementos vitamínico s e uma exposição solar de 10 a 15 minutos por dia.
Agência LUSA
2007-02-06 09:23:49

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Friday, February 02, 2007

How to Beat Test Stress

You're in the middle of a test. Your heart is pounding. You're hyperventilating. Where are these symptoms coming from? They're actually part of a primitive survival mechanism known as the "fight or flight" response. Back in the good old days before standardized tests were even on the horizon, this response prepared primitive human beings for intense physical exertion, such as spearing wild boars, or running from predators. The problem is that these same reactions might hamper a modern-day test-taker like you from delivering your best performance. After all, it's not like you can spear the test booklet with your number 2 pencil or run from the exam room screaming (or at least you shouldn't).

Now, even though you are experiencing some very physical symptoms, you may be surprised to find out that it's actually your thoughts that are producing your stress. You're reacting not so much to the test itself, but rather to your perceptions about the test. And that's good news. Unless you can infiltrate the Educational Testing Service, you have no control over the SAT, but you can control your thoughts about it.


Get Ready
Seeing yourself as a victim of the test is neither productive nor accurate. When you feel out of control and helpless, you're tapping into the negative side of stress, or distress. It's not possible to rid yourself of stress entirely, but you can learn to manage it and function effectively in spite of it. You can even harness that rush of adrenaline to get energized and sharpen your focus.

Begin to prepare mentally by dispelling the myths and half-truths that you've been telling yourself about the exam. By shifting your negative thoughts to more positive ones, you can begin to take some control.

Here's an example of some typical self-defeating chatter:

I never do well on standardized tests. It's so unfair that I even have to take this stupid test. They're probably going to ask me all the stuff I don't know.

Now, here's a more empowering way to perceive the same situation:

I can't control what questions are on this test, but I'm confident that I'll do my personal best because I'm well-prepared. I'm choosing to take the SAT because I want the opportunities that it will give me.

Once you've gotten your thoughts under control, it's time to start taking a proactive approach to preparing for the exam itself. Studies have shown that rehearsing a stressful event can significantly reduce your fear of it. Think of preparation as a "stress rehearsal."

There are currently many test prep product on the market, which will allow you to become familiar with the test's format and practice the different question types you will encounter on test day. Preparing will make the actual test seem more familiar and less intimidating. Face your fears directly by focusing on your weakest areas. You may still feel anxious, but you'll grow accustomed to the feeling, and then anxiety will no longer hurt your performance. Studies have shown that the subconscious mind does not easily distinguish between imagined and real experiences, so visualizing a successful testing experience can help you to succeed on the real test and help you to control stress as well.


Get Set
Make strategy your focus during the final days before the exam. Don't try to cram in a lot of new material. Review what you have already learned and let go of the rest. Don't even think of taking a practice test the night before the real thing! At that point, you know what you know, and you just want to remain calm and confident so you can access the knowledge you have on test day.

Minimize the risk of confronting any other anxiety-producing situations by having a plan in place. Make sure you can find the test center. You don't want to get lost on test day. Pack up your admissions card, calculator, pencils, and test center directions the night before. Being hungry or tired can make you feel jittery, so get a full night's rest and wake early enough to have a light, healthy breakfast. Leave enough time to get to the test center without rushing, so that you don't raise your anxiety level right from the start.h

Go
You may feel your stress start to spiral just as the test is about to begin. Remember all the preparation you've done: you know what you're doing, and you're not likely to be surprised by anything. Also, keep the exam in perspective - your life will not be wholly determined by your performance on this one exam. Bear your last resorts in mind, even though it is not likely that you will have to use them. You can always cancel your scores, and take the exam again if need be.

If a negative thought creeps into your brain during the test, quickly replace it with a positive one, and then resume the business at hand. Zap out a thought like "Typical, I got math first and I stink at math" with one like "Good, I can get a math section over with while I'm alert." And don't add to your stress by blaming yourself for having it. A certain amount of anxiety is perfectly natural, and lets you know that you're focused on the task at hand.

Stick to your plan during the test, staying as engaged in the questions as possible. Don't get bogged down on tough questions - eliminate answer choices, make educated guesses and keep moving forward. If you know that you're not likely to answer the most difficult questions correctly and that even looking at them is going to make you panic, plan to skip them. And it may seem obvious, but don't forget to breathe. Stress can cause you to hold your breath without you even realizing it, and that can impede your ability to concentrate. Taking deep breaths will relax your body and clear your mind.

Finally, plan to do something fun and relaxing after the exam. That will make the test seem less like "the be all and end all," and remind you that life goes on regardless of how you do on the SAT. It really does.

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