Dr.Serdest TASDELEN: January 2017

America's homeless doctor brings health care to streets

Pittsburgh (CNN)Dr. Jim Withers used to dress like a homeless person. On purpose.

Two to three nights a week, he rubbed dirt in his hair and muddied up his jeans and shirt before walking the dark streets of Pittsburgh, searching for the very people he was trying to emulate.

Los Angeles declares 'state of emergency' on homelessness

Withers wanted to connect with those who had been excluded from his care.

"I was actually really shocked how ill people were on the street. It was like going to a third-world country," he said. "Young, old, people with mental illness, runaway kids, women (who) fled domestic violence, veterans. And they all have their own story."

By Christie O'Reilly, CNN

Updated 2109 GMT (0509 HKT) March 21, 2016

To the link : http://edition.cnn.com/2015/05/07/us/cnn-heroes-homeless-doctor-jim-withers/

Why Do We Sleep, Anyway?

At a Glance

Our bodies regulate sleep in much the same way that they regulate eating, drinking, and breathing. This suggests that sleep serves a similar critical role in our health and well-being.

Although it is difficult to answer the question, "Why do we sleep?" scientists have developed several theories that together may help explain why we spend a third of our lives sleeping.

Understanding these theories can help deepen our appreciation of the function of sleep in our lives.

Hunger and Eating; Sleepiness and Sleep

While we may not often think about why we sleep, most of us acknowledge at some level that sleep makes us feel better. We feel more alert, more energetic, happier, and better able to function following a good night of sleep. However, the fact that sleep makes us feel better and that going without sleep makes us feel worse only begins to explain why sleep might be necessary.

One way to think about the function of sleep is to compare it to another of our life-sustaining activities: eating. Hunger is a protective mechanism that has evolved to ensure that we consume the nutrients our bodies require to grow, repair tissues, and function properly. And although it is relatively easy to grasp the role that eating serves— given that it involves physically consuming the substances our bodies need—eating and sleeping are not as different as they might seem.

Both eating and sleeping are regulated by powerful internal drives. Going without food produces the uncomfortable sensation of hunger, while going without sleep makes us feel overwhelmingly sleepy. And just as eating relieves hunger and ensures that we obtain the nutrients we need, sleeping relieves sleepiness and ensures that we obtain the sleep we need. Still, the question remains: Why do we need sleep at all? Is there a single primary function of sleep, or does sleep serve many functions?

An Unanswerable Question?

Scientists have explored the question of why we sleep from many different angles. They have examined, for example, what happens when humans or other animals are deprived of sleep. In other studies, they have looked at sleep patterns in a variety of organisms to see if similarities or differences among species might reveal something about sleep's functions. Yet, despite decades of research and many discoveries about other aspects of sleep, the question of why we sleep has been difficult to answer.

The lack of a clear answer to this challenging question does not mean that this research has been a waste of time. In fact, we now know much more about the function of sleep, and scientists have developed several promising theories to explain why we sleep. In light of the evidence they have gathered, it seems likely that no single theory will ever be proven correct. Instead, we may find that sleep is explained by two or more of these explanations. The hope is that by better understanding why we sleep, we will learn to respect sleep's functions more and enjoy the health benefits it affords.

This essay outlines several current theories of why we sleep. To learn more about them, be sure to check out the "Bookshelf" feature at the end of this essay. There you'll find links to articles by researchers who are studying this fascinating question.

Theories of Why We Sleep

Inactivity Theory

One of the earliest theories of sleep, sometimes called the adaptive or evolutionary theory, suggests that inactivity at night is an adaptation that served a survival function by keeping organisms out of harm’s way at times when they would be particularly vulnerable. The theory suggests that animals that were able to stay still and quiet during these periods of vulnerability had an advantage over other animals that remained active. These animals did not have accidents during activities in the dark, for example, and were not killed by predators. Through natural selection, this behavioral strategy presumably evolved to become what we now recognize as sleep.

A simple counter-argument to this theory is that it is always safer to remain conscious in order to be able to react to an emergency (even if lying still in the dark at night). Thus, there does not seem to be any advantage of being unconscious and asleep if safety is paramount.

Energy Conservation Theory

Although it may be less apparent to people living in societies in which food sources are plentiful, one of the strongest factors in natural selection is competition for and effective utilization of energy resources. The energy conservation theory suggests that the primary function of sleep is to reduce an individual’s energy demand and expenditure during part of the day or night, especially at times when it is least efficient to search for food.

Research has shown that energy metabolism is significantly reduced during sleep (by as much as 10 percent in humans and even more in other species). For example, both body temperature and caloric demand decrease during sleep, as compared to wakefulness. Such evidence supports the proposition that one of the primary functions of sleep is to help organisms conserve their energy resources. Many scientists consider this theory to be related to, and part of, the inactivity theory.

Restorative Theories

Another explanation for why we sleep is based on the long-held belief that sleep in some way serves to "restore" what is lost in the body while we are awake. Sleep provides an opportunity for the body to repair and rejuvenate itself. In recent years, these ideas have gained support from empirical evidence collected in human and animal studies. The most striking of these is that animals deprived entirely of sleep lose all immune function and die in just a matter of weeks. This is further supported by findings that many of the major restorative functions in the body like muscle growth, tissue repair, protein synthesis, and growth hormone release occur mostly, or in some cases only, during sleep.

Other rejuvenating aspects of sleep are specific to the brain and cognitive function. For example, while we are awake, neurons in the brain produce adenosine, a by-product of the cells' activities. The build-up of adenosine in the brain is thought to be one factor that leads to our perception of being tired. (Incidentally, this feeling is counteracted by the use of caffeine, which blocks the actions of adenosine in the brain and keeps us alert.) Scientists think that this build-up of adenosine during wakefulness may promote the "drive to sleep." As long as we are awake, adenosine accumulates and remains high. During sleep, the body has a chance to clear adenosine from the system, and, as a result, we feel more alert when we wake.

Brain Plasticity Theory

One of the most recent and compelling explanations for why we sleep is based on findings that sleep is correlated to changes in the structure and organization of the brain. This phenomenon, known as brain plasticity, is not entirely understood, but its connection to sleep has several critical implications. It is becoming clear, for example, that sleep plays a critical role in brain development in infants and young children. Infants spend about 13 to 14 hours per day sleeping, and about half of that time is spent in REM sleep, the stage in which most dreams occur. A link between sleep and brain plasticity is becoming clear in adults as well. This is seen in the effect that sleep and sleep deprivation have on people's ability to learn and perform a variety of tasks.

This theory and the role of sleep in learning are covered in greater detail in Sleep, Learning, and Memory.

Although these theories remain unproven, science has made tremendous strides in discovering what happens during sleep and what mechanisms in the body control the cycles of sleep and wakefulness that help define our lives. While this research does not directly answer the question, "Why do we sleep?" it does set the stage for putting that question in a new context and generating new knowledge about this essential part of life.

For more about why we sleep, watch the video Why Sleep Mattersand explore Consequences of Insufficient Sleep.

from : http://healthysleep.med.harvard.edu/healthy/matters/benefits-of-sleep/why-do-we-sleep

This content was last reviewed on December 18, 2007

USMLE Preparation Tactics

As most medical students know, the U.S. Medical Licensing Examination Step 1 — or “The Boards,” as the exam is commonly called — is challenging, and arguably the most difficult of the three-part exam series. Understanding what’s on the test and how to prepare for it are key to surmounting this first hurdle on your path to a medical career.
The USMLE Step 1 tests your ability to apply a vast array of basic science knowledge to medical practice. In short, it is a multiple-choice, computer-based test that takes about eight hours to complete. The exam content covers the systems and processes of the following science topics:

Anatomy

Behavioral sciences

Biochemistry

Biostatistics and epidemiology

Microbiology

Pathology

Pharmacology

Physiology

Genetics

Aging

Immunology

Nutrition

Molecular and cell biology

When Should I Take Step 1?
Preparation Resources
1. Prep Courses
2. Question Banks
3. Study Guides
Preparation Strategies
Test-Taking Strategies

Complete two blocks

Take a 10-minute stretch/bathroom break

Complete two blocks

Take a 30-minute lunch break

Complete two blocks

Take a 10-minute stretch/bathroom/snack break

Complete one block

Follow this link for a comprehensive overview of the USMLE Step 1 and its component parts.
The best time to take Step 1 is when basic science knowledge is fresh in your mind and you’ve had sufficient time to study. The Boards generally require the most preparation of all of the USMLE steps, so most medical schools build one to two months of dedicated study time into the curriculum once students complete the basic science courses. And many test-prep companies suggest two to three months of nearly full-time study to prepare adequately.
Medical schools that follow a traditional program structure recommend taking Step 1 late in the second year, which is the point at which students will have finished the science curricula that forms the basis of the exam. By contrast, those schools that have adopted a newer program architecture that weaves together these basic science classes with early clinical experience may suggest that their candidates take Step 1 at any point between the end of the first year to the third year. Check with your medical school to learn its specific recommendations.
There are a range of different resources that students can utilize to prepare for the USMLE Step 1. These fall broadly into three categories:
Test-prep courses offer structured classroom lectures and preparation materials.
Your Medical SchoolSome medical schools offer preparation courses as part of the curriculum. If courses are available, it’s definitely worthwhile to avail yourself of the opportunity to take them.
Private CoursesAs with the MCAT, there are Step 1 preparation courses offered by well-known national companies like Kaplan as well as smaller, regional providers. And while most students are familiar with the big names, some of the lesser known courses, such as USMLE Success Academy, Doctors in Training, and Becker Reviews receive higher reviews.
Please note that you do not need to take a live course to excel at USMLE Step 1. Courses are best for students who do well in structured settings with a defined program and schedule. If you decide to pursue this option, be sure to ask about the timeline, study materials, teachers’ backgrounds, student-to-teacher ratio, and the company’s success rate for each of the courses you’re considering. These classes can run into thousands of dollars, so be sure you’re getting exactly what you need if you go this route.
Question banks are essential for USMLE Step 1 preparation. They provide hundreds of questions that students can take as full tests, blocks, or by category — either timed or untimed — and they provide explanations of each answer.
USMLE Free Practice QuestionsEach year, USMLE offers free tutorial and practice test items for Step 1. These include a tutorial, overview, and three question blocks, which can be timed. This is a great resource to begin with so you can quickly learn how to navigate the test’s computer system and get comfortable with the question style. The program is only available for PCs.
NBME Self-Assessment ExamsThe National Board of Medical Examiners (NBME) offers a comprehensive basic science self-assessment (CBSSA) for $50. This resource, in conjunction with the USMLE free practice questions, is helpful to see where you stand early in your preparation and to highlight those areas in which you need to focus on more closely.
Proprietary Question BanksThere are many companies that offer their own proprietary question banks. Students can subscribe for a fee, which affords them access to the questions for periods typically ranging from 30 to 180 days. Several of the most popular options are UWorld, Kaplan QBank, and USMLE Rx Qmax.
Free Question BanksThere are also free question banks available, if you are willing to scour the Web and cobble together resources. Ben White, a medical resident at the time of his posting, gathered an excellent set of these resources for readers of his blog. That said, collecting all of these questions is a time-consuming undertaking, and you’re probably better off paying (if you are able) for the formal resources so you can spend your time studying.
First Aid for the USMLE Step 1“First Aid” has long been known as the bible of Step 1 preparation books. Many argue that a good schedule combined with “First Aid” and a question bank are all you need to excel on Step 1. As you study, transfer all of the notes you’ve taken in other books into First Aid so that it becomes the only text you use in your final review.
Subject BooksThere are many preparation books for each subject, but be careful not to get overwhelmed by trying to study from 20 different books at the same time. The best strategy is to use one board book as part of your classroom studying while you are learning the subject, and then transfer these notes to “First Aid” when you begin Step 1 preparation. Kaplan Lecture Notes rate highly in most subjects, but there are others that are effective, as well.
Below is a list of the most popular Step 1 books by subject:
Anatomy: “High-Yield Gross Anatomy”
Behavioral Science: “High-Yield Behavioral Science” or “BRS Behavioral Science”
Biochemistry: “Lippincott’s Illustrated Reviews: Biochemistry”, “BRS Biochemistry and Molecular Biology”, or “High-Yield Biochemistry”
Biostatistics: “High Yield Biostatistics”
Embryology: “High-Yield Embryology” or “BRS Embryology”
Genetics: “High Yield Genetics”
Histology: “High-Yield Histology” or “BRS Cell Biology and Histology”
Immunology: “High-Yield Immunology or “Review of Medical Microbiology and Immunology”
Medical Ethics: “Master the Boards USMLE Medical Ethics: The Only USMLE Ethics High-Yield Review “ or “Khan's Cases: Medical Ethics”
Microbiology: “Clinical Microbiology Made Ridiculously Simple”
Neuroanatomy: “High-Yield Neuroanatomy” or “Clinical Neuroanatomy Made Ridiculously Simple”
Pathology: “Rapid Review Pathology” (Goljan)
Pharmacology: “Lippincott’s Illustrated Reviews: Pharmacology” or “Katzung and Trevor's Pharmacology”
Physiology: “BRS Physiology”
Once you’ve decided whether you’re going to enroll in a prep course, and which question bank and books you’ll be using to study, you can also begin to practice the following preparation strategies:
Start preparing for the USMLE Step 1 the moment you set foot into medical school by using board books as you are taking courses in each subject. For example, while you are studying microbiology, review “Clinical Microbiology Made Ridiculously Simple.”
Before any official studying begins, make a schedule that includes breaks and time to eat, as well as days for taking full practice tests. If your schedule isn’t working, change it so you can get to all of these activities — each one is important!
Take a practice test early to see where you stand.
Complete as many practice questions as you can. Go through your question bank — then go through it again.
Be sure to do as many full-length practice tests as possible in a test-like setting to ensure you are finishing blocks in the allotted 60 minutes and preparing your body for a long test day. Prometric Test Centers allow you to take a USMLE practice test for a fee that ranges from $75 to $266, depending on where you are taking it. This practice session is worth every penny. Schedule it at least a month before your actual test date so you have adequate time to sharpen your skills if the test doesn’t go as you hoped.
Study what you don’t know. It’s easy to fall into the trap of studying the subjects you’re already confident in, but if you’ve mastered a subject, spend time focusing on areas in which you are struggling.
Study with a friend, and use humor and other potential mnemonics to help with memorization. Remember, the amygdala (emotion) is connected to the hippocampus (memory).
Take breaks in your study day. Get outside. Exercise.
-If you are retaking the test, focus your preparation on the areas in which you did not excel. Fortunately, the score report from your previous test provides graphical performance profiles for each testing category that will allow you to see where you need the most work.
When the test day arrives, here are some tips to help you approach the USMLE Step 1 with assurance that you will be successful:
Know how to get to the test site, and do a practice run. There is nothing worse than feeling rushed on the morning of the test.
Get to the test site at least 30 minutes early, and be sure to have a current picture ID with your signature, along with a printed copy of your scheduling permit.
Bring a lunch, snack, and ear plugs.
Answer every question. Wrong answers do not count against you.
Think of the exam as seven mini-tests — that is, seven blocks of 44 questions each.
Focus solely on the block you are in, complete it, clear your mind, and move to the next block.
Be sure you have checked all the questions in a block before hitting “end.” Once a block is ended, you cannot re-enter it to review your answers.
Gain extra break time by skipping the optional 15-minute tutorial. At this point, you should be so familiar with how the test works that you won’t need the tutorial — but an extra break will be welcome.
Decide your plan for breaks ahead of time, and practice the strategy. For example, you could try the following plan:
Or you could decide to complete four blocks, take a quick lunch break, and return to complete the final three blocks. Whatever strategy you choose, perform it over and over on practice tests to simulate the real test environment and train your body to become accustomed to the challenge of a long test day.
Get a great night’s sleep the night before the exam. Anecdotally, students and admissions counselors report that this night of sleep is one of the most important (and easily accomplished) steps you can take to enhance test performance.
Though the USMLE Step 1 may be one of the most challenging exams you’ll ever take, with diligent and focused work, it is possible to be prepared and confident when you walk in on test day.
Good luck!

Source :https://www.noodle.com/articles/tips-to-prepare-for-and-ace-the-usmle-step-1

Dr.Serdest TASDELEN