Mengenal Komponen Perangkat Keras dari RFID (Radio Frequency Identification)
Tulisan ini merupakan pengantar untuk memahami RFID (Radio Frequency Identification) yang ditujukan bagi pembaca yang masih sangat awam dengan teknologi ini. Pada bagian awal dari tulisan ini dibahas tentang konfigurasi umum, dan kemudian berturut-turut akan dibahas mengenai metode kerja RFID, tag beserta jenis-jenisnya serta sebagai bagian akhir dokumen ini akan diberikan ulasan tentang packaging terhadap tag tersebut.
Konfigurasi Umum
Pada intinya, RFID merupakan teknologi yang berfungsi untuk melakukan deteksi dan identifikasi terhadap suatu obyek melalui data yang ditransmisikan melalui frekuensi radio. Sistem tersebut minimal memerlukan sebuah tag (yang berfungsi sebagai transponder), sebuah reader (yang berfungsi sebagai interrogator), dan sebuan antenna (yang berfungsi sebagai coupling device). Reader biasanya terhubung dengan dengan sebuah host computer atau perangkat lainnya yang memiliki kecerdasan untuk memroses lebih lanjut tag data dan memutuskan untuk mengambil suatu tindakan. Host computer biasanya merupakan sebuah bagian dari suatu jaringan komputer yang lebih besar lagi, dan dapat terhubung ke Internet.
Salah satu elemen penting pada RFID adalah data transfer. Data transfer terjadi ketika terjadi hubungan antara sebuah tag dengan sebuah reader, yang dikenal dengan coupling, melalui antenna baik yang terpasang pada tag tersebut maupun pada reader seperti yang diilustrasikan pada gambar berikut ini.
Metode Coupling
Coupling pada kebanyakan sistem-sistem RFID menggunakan metode magnetic(inductive) atau electromagnetic (backscatter). Metode yang digunakan tersebut bergantung pada harga, ukuran, kecepatan, dan jangkauan pembacaan serta keakuratan.
Pada inductively coupled RFID systems memiliki jangkauan yang pendek, yang biasanya dalam orde inchi. Jenis ini banyak digunakan sebagai access control yang hanya memerlukan jangkauan pendek. Pada kasus ini, sebuah tag hanya akan melakukan unlock atau pembukaan kunci terhadap sebuah RFID-enabled door lock ketika tag berada pada jangkauan yang cukup dekat dengan reader, sehingga pintu tidak akan pernah terbuka ketika seseorang yang membawa tag di dalam dompet atau sakunya berjalan melintasi pintu yang memang tanpa tujuan untuk membuka kunci pintu tersebut.
Pada umumnya komunikasi antara sebuah tag dengan sebuah reader terjadi melalui sebuah physical principle yang dikenal sebagai sebuah backscatter modulation. Pada proses ini, sebuah reader mengirimkan sinyal (yang pada dasarnya merupakan energi listrik) kepada sebuah tag, dan tag akan menanggapinya dengan memantulkan sebagian dari energi ini kembali ke reader. Sebuah charge device seperti sebuah kapasitor, yang berada dalam suatu tag, memungkinkan tag untuk dapat memantulkan kembali sinyal. Ketika tag menerima sinyal tersebut berarti kapasitor dalam keadaan mengisi energi listrik, sedangkan ketika tag memberikan tanggapan sinyal berarti kapasitor dalam kondisi discharge.
Elemen penting lainnya dalam RFID system adalah frekuensi untuk operasi antara tag dan reader. Pemilihan suatu frekuensi didorong oleh kebutuhan aplikasi seperti kecepatan, akurasi dan kondisi-kondisi lingkungan, yang mungkin melibatkan juga regulasi dan standar yang mengatur suatu aplikasi. Sebagai contohnya adalah RFID applications for animal tagging atau aplikasi RFID yang dipasang pada hewan, pada umumnya sudah beroperasi menggunakan pita frekuensi 135 KHz. Adapun frekuensi-frekuensi yang populer digunakan pada RFID adalah sebagai berikut:
Low Frequency (LF): kurang dari 135KHz
High Frequency (HF): pada 13.56 MHz
Ultra High Frequency (UHF) antara 433 MHz s/d 860 to 930 MHz
Microwave pada 2.45 GHz dan 5.8 GHz
Hardware components atau komponen-komponen perangkat keras dari sebuah RFID, yang bertanggung jawab untuk melakukan identifikasi, penerimaan dan pengiriman data, harus didukung oleh software components atau komponen-komponen perangkat lunak. Software components ini bertanggunjawab untuk melakukan manajemen dan rekayasa terhadap data yang ditransmisikan antara tag dan reader maupun antara reader dan host computer. Hal tersebut dapat diilustrasikan pada gambar 2 berikut.
Tag
Tag pada dasarnya merupakan transponder (yang berarti transmitter dan receiver) yang dapat menyimpan data untuk ditransmisikan kepada reader ketika tag tersebut 'diinterogasi' oleh suatu reader. Tag yang paling umum saat ini terdiri dari sebuah IC(Integrated Circuit ) yang dilengkapi dengan memory, yang pada dasarnya sudah menjadi sebuah microprocessor chip. Jenis lain dari tag adalah chipless yang tidak memiliki onboard IC. Chipless tags paling efektif digunakan untuk aplikasi-aplikasi yang sederhana. Berikut ini digambarkan sebuah microprocessor chip.
Ketika tag sedang "diinterogasi", terjadi proses penyimpanan dan pengiriman data dari memory. Sebuah tag dapat melakukan tugas-tugas mendasar (membaca/menulis dari/ke memory) atau memanipulasi data dengan berbagai cara. Ada beragam artibut dari memory pada tag, antara lain; read-only (RO), write once-read many (WORM), atau read-write (RW).
Biasanya semakin tinggi kemampuan menulis dari memory maka semakin mahal pula harga dari tag tersebut. Suatu aplikasi yang makin canggih juga biasanya menuntut kemampuan tag yang lebih tinggi. Namun demikian read-only tags tetap diperlukan karena untuk menghilangkan resiko adanya kekeliruan atau kesengajaan untuk melakukan over-writing terhadap tag data.
Jenis-jenis tag
Jenis tag yang populer digunakan saat ini adalah passive tags. Jenis ini memiliki beragam bentuk dan dapat diproduksi dengan biaya yang sangat rendah karena tidak memerlukan tenaga batere. Passive tags memperoleh tenaga dari proses emisi energi elektromagnetis yang berasal dari reader. Saat ini banyak solusi yang muncul dengan menggunakan passive tag technology, seperti animal tracking atau pelacakan binatang, asset management atau manajemen aset, industrial automation atau otomatisasi industri, electronic article surveillance atau keamanan elektronik, dan access control applications atau aplikasi-aplikasi pengendali akses seperti penguncian pintu.
Tidak seperti passive tags, active tags memiliki sebuah battery on board yang berfungsi sebagai sumber tenaga bagi tag dan memungkinkan adanya pembacaan pada jangkauan yang lebih jauh, akurasi yang lebih baik, pertukaran informasi yang lebih kompleks, dan kemampuan pemrosesan yang lebih kaya. Active tag yang mempunyai sumber tenaga sendiri tersebut tidak memerlukan reader untuk memberikan tenaganya untuk diolah dan digunakan sebagai sumber tenaga bagi active tag. Karena menggunakan batere inilah maka active tags memiliki usia hidup yang terbatas. Salah satu penggunaan active tags yang umum adalah untuk tracking terhadap obyek-obek yang mempunyai nilai yang tinggi dengan jangkauan yang luas seperti pengiriman military supplies di seluruh dunia.
Di samping active tags dan passive tags ada lagi kelas yang disebut semi-active atau semi-passive. Tag jenis ini masih menggunakan elektromagnetis yang berasal dari reader untuk "membangunkan" tag untuk dapat memfungsikan batere. Tenaga dari battery on board ini digunakan untuk mengoperasikan IC dan mengerjakan tugasnya. Tag jenis ini digunakan sejak tahun 80-an pada electronic toll collection. Batere yang digunakan pada tag jenis ini biasanya bisa berumur bertahun-tahun karena tenaga batere tersebut hanya digunakan ketika "dibangunkan" oleh reader.
Packaging
Tag dikemas dalam berbagai bentuk, ukuran, dan materi sesuai dengan kebutuhan aplikasi dari RFID. Dimensi dari tag seringkali tergantung pada bentuk dan ukuran antenna dari tag tersebut. Adapun contoh-contoh packaging dari tag tersebut adalah sebagai berikut:
Kartu plastik (dengan media seukuran kartu nama) untuk pembayaran otomatis.
Kartu kunci atau gantungan kunci untuk access control atau pengendali akses.
Bentuk-bentuk yang kecil yang dapat dimasukan ke permukaan kulit atau diminum (dengan media seukuran obat yang bisa diminum).
Bentuk yang bisa dikaitkan pada berbagai produk pakaian.
Memory merupakan bagian yang penting dari RFID systems yang berbasiskan IC. Parameter memory yang paling penting di sini adalah ukuran memory, di samping konfigurasi dan kecepatan memory. Pada EAS (Electronic Article Surveillance) biasanya digunakan 1 bit of memory yang harganya tidak mahal. Ukuran memory ini tergantung dari aplikasinya, dan pada EPC (Electronic Product Code) bisa membutuhkan lebih dari 2 kbits.
Selasa, Oktober 07, 2008
Sabtu, September 20, 2008
Top 10 Myths about the Brain
The brain is one of the most amazing organs in the human body. It controls our central nervous system, keeping us walking, talking, breathing and thinking. The brain is also incredibly complex, comprising around 100 billion neurons. There's so much going on with the brain that there are several different fields of medicine and science devoted to treating and studying it, including neurology, which treats physical disorders of the brain; psychology, which includes the study of behavior and mental processes; and psychiatry, which treats mental illnesses and disorders. Some aspects of each tend to overlap, and other fields cross into study of the brain as well.
These disciplines have been around in some form since ancient times, so you'd think that by now we'd know all there is to know about the brain. Nothing could be further from the truth. After thousands of years of studying and treating every aspect of it, there are still many facets of the brain that remain mysterious. And because the brain is so complex, we tend to simplify information about how it works in order to make it more understandable.
Both of these things put together have resulted in many myths about the brain. Most aren't completely off -- we just haven't quite heard the whole story. Let's look at 10 myths that have been circulating about the brain, starting with, of all things, its color.
Brain Myth 10: Your Brain Is Gray
Have you given any thought to the color of your brain? Maybe not, unless you work in the medical field. We have all colors of the rainbow in our bodies in the form of blood, tissue, bone and other fluids. But you may have seen preserved brains sitting in jars in a classroom or on TV. Most of the time, those brains are a uniform white, gray or even yellowish hue. In actuality, though, the living, pulsing brain currently residing in your skull isn't just a dull, bland gray; it's also white, black and red.
Like many myths about the brain, this one has a grain of truth, because much of the brain is gray. Sometimes the entire brain is referred to as gray matter. Mystery writer Agatha Christie's famous detective Hercule Poirot often spoke of using his "little gray cells." Gray matter exists all throughout the various parts of the brain (as well as in the spinal cord); it consists of different types of cells, such as neurons. However, the brain also contains white matter, which comprises nerve fibers that connect the gray matter.
The black component is called substantia nigra, which is Latin for (you guessed it) "black substance." It's black because of neuromelanin, a specialized type of the same pigment that colors skin and hair, and it's a part of the basal ganglia. Finally, we have red -- and that's thanks to the many blood vessels in the brain. So why are preserved brains chalky looking and dull instead of spongy and colorful? It's due to the fixatives, such as formaldehyde, that keep the brain preserved.
From color, to sound -- the next myth may have you rethinking your musical choices.
Brain Myth 9: Listening to Mozart Makes You Smarter
Don't you just feel cultured when you tune in to a classical music station and take in an opera or a symphony by a great composer like Mozart? Baby Einstein, a company that makes DVDs, videos and other products for babies and toddlers incorporating classical art, music, and poetry, is a million-dollar franchise. Parents buy the products because they believe that exposure to great art (like Baby Mozart DVDs and CDs) can be good for their children's cognitive development. There are even classical music CDs designed to be played to developing fetuses. The idea that listening to classical music can increase your brainpower has become so popular that it's been dubbed "the Mozart effect." So how did this myth start?
In the 1950s, an ear, nose and throat doctor named Albert Tomatis began the trend, claiming success using Mozart's music to help people with speech and auditory disorders. In the 1990s, 36 students in a study at the University of California at Irvine listened to 10 minutes of a Mozart sonata before taking an IQ test. According to Dr. Gordon Shaw, the psychologist in charge of the study, the students' IQ scores went up by about 8 points. The "Mozart effect" was born.
A musician named Dan Campbell trademarked the phrase and created a line of books and CDs based on the concept, and states such as Georgia, Florida and Tennessee set aside money for classical music for babies and other young children. Campbell and others have gone on to assert that listening to Mozart can even improve your health.
However, the original University of California at Irvine study has been controversial in the scientific community. Dr. Frances Rauscher, a researcher involved in the study, stated that they never claimed it actually made anyone smarter; it just increased performance on certain spatial-temporal tasks. Other scientists have been unable to replicate the original results, and there is currently no scientific information to prove that listening to Mozart, or any other classical music, actually makes anyone smarter. Rauscher even said that the money spent by those states might be better spent on musical programs -- there's some evidence to show that learning an instrument improves concentration, self-confidence and coordination.
Mozart certainly can't hurt you, and you might even enjoy it if you give it a try, but you won't get any smarter.
Brain Myth 8: You Get New Brain Wrinkles When You Learn Something
When you think about how your brain looks, you probably picture a roundish, two-lobed gray mass covered in "wrinkles." As humans evolved as a species, our brains grew larger to accommodate all of the higher functions that set us apart from other animals. But in order to keep the brain compact enough to fit into a skull that would actually be in proportion with the rest of our body size, the brain folded in on itself as it grew. If we unfolded all of those ridges and crevices, the brain would be the size of a pillowcase. The ridges are called sulci and the crevices are called gyri. Several of these ridges and crevices even have names, and there are variations in exactly how they look from person to person.
We don't start out with wrinkly brains, however; a fetus early in its development has a very smooth little brain. As the fetus grows, its neurons also grow and migrate to different areas of the brain, creating the sulci and gyri. By the time it reaches 40 weeks, its brain is as wrinkled as yours is (albeit smaller, of course). So we don't develop new wrinkles as we learn. The wrinkles we're born with are the wrinkles we have for life, assuming that our brains remain healthy.
Our brains do change when we learn -- it's just not in the form of additional sulci and gyri. This phenomenon is known as brain plasticity. By studying changes in the brains of animals like rats as they learn tasks, researchers have discovered that synapses (the connections between neurons) and the blood cells that support neurons grow and increase in number. Some believe that we get new neurons when we make new memories, but this hasn't yet been proven in mammalian brains like ours.
If you've ever gotten the feeling that there were hidden messages in commercials, TV shows or movies, the next myth should interest you.
Brain Myth 7: You Can Learn Through Subliminal Messages
The concept of subliminal messages feeds into our suspicions about what the government, big corporations and media are really trying to tell us. A subliminal message (meaning, below "limen," or our conscious perception threshold) is a message embedded into images or sound meant to penetrate into our subconscious and influence our behavior. The first person to coin the term was James Vicary, a market researcher. In 1957, Vicary stated that he inserted messages into a showing of a movie in New Jersey. The messages, which flashed for 1/3000th of a second, told moviegoers to drink Coca-Cola and eat popcorn.
According to Vicary, Coke sales in the theater increased by more than 18 percent and popcorn sales by more than 57 percent, proving that his subliminal messages worked. Books published in the late 1950s and early 1970s outlined how advertisers could use techniques like Vicary's to convince consumers to buy their products. Some radio and TV commercials included subliminal messages, but many networks and professional associations banned them. In 1974, the FCC banned the use of subliminal advertising.
But did the messages work? Turns out, Vicary actually lied about the results of his study. Subsequent studies, including one which flashed the message "Call now" during a broadcast on a Canadian TV station, had no effect on viewers. The infamous 1990s Judas Priest trial, in which the families of two boys who committed suicide claimed that a song told the boys to do it, ended with the judge stating that there was no scientific evidence in their favor. Yet some people still claim that music, as well as advertisements, contains hidden messages.
So listening to those self-help tapes while you sleep probably can't hurt you, but they aren't likely to help you quit smoking, either.
When it comes to the human brain versus other animals' brains, does size matter? Check out our next myth to find out.
Brain Myth 6: The Human Brain Is the Biggest Brain
Many animals can use their brains to do some of the things that humans can do, such as finding creative ways to solve problems, exhibiting self-awareness, showing empathy toward others and learning how to use tools. But although scientists can't agree on a single definition of what makes a person intelligent, they do generally agree that humans are the most intelligent creatures on Earth. In our "bigger is better" society, then, it might stand to reason that humans should have the biggest brains of all animals, because we're the smartest. Well, not exactly.
The average adult human brain weighs about 3 pounds (1,361 grams). The dolphin -- a very intelligent animal -- also has a brain that weighs about 3 pounds on average. But a sperm whale, not generally considered to be as intelligent as a dolphin, has a brain that weighs about 17 pounds (7,800 grams). On the small end of the scale, a beagle's brain is about 2.5 ounces (72 grams), and an orangutan's brain is about 13 ounces (370 grams). Both dogs and orangutans are pretty smart animals, but they have small brains. A bird like a sparrow has a brain that weighs less than half an ounce (1 gram).
You may notice something important in all of those comparisons. An average dolphin's body weighs about 350 pounds (158.8 kilograms), while a sperm whale can weigh as much as 13 tons. In general, the larger the animal, the larger the skull, and therefore, the larger the brain. Beagles are fairly small dogs, at about 25 pounds (11.3 kg) maximum, so it stands to reason that their brains would also be smaller. The relationship between brain size and intelligence isn't really about the actual weight of the brain; it's about the ratio of brain weight to the entire body weight. For humans, that ratio is about 1-to-50. For most other mammals, it's 1-to-180, and for birds, it's 1-to-220. The brain takes up more weight in a human than it does in other animals.
Intelligence also has to do with the different components of the brain. Mammals have very large cerebral cortexes, unlike birds, fish or reptiles. The cerebellum in mammals houses the cerebral hemispheres, which are responsible for higher functions like memory, communication and thinking. Humans have the largest cerebral cortex of all mammals, relative to the size of their brains.
Heads up; we're looking at a grislier brain myth next.
Brain Myth 5: Your Brain Stays Active After You Get Decapitated
At one time in history, decapitation was one of the preferred methods of execution, in part thanks to the guillotine. Although many countries that execute criminals have dispatched with the method, it's still performed by certain governments, terrorists and others. There's nothing more final than the severing of one's head. The guillotine came about because of the desire for a quick, relatively humane death. But how quick is it? If your head were cut off, would you still be able to see or otherwise move it, even for just a few seconds?
This concept perhaps first appeared during the French Revolution, the very time period in which the guillotine was created. On July 17, 1793, a woman named Charlotte Corday was executed by guillotine for the assassination of Jean-Paul Marat, a radical journalist, politician and revolutionary. Marat was well-liked for his ideas and the mob awaiting the guillotine was eager to see Corday pay. After the blade dropped and Corday's head fell, one of the executioner's assistants picked it up and slapped its cheek. According to witnesses, Corday's eyes turned to look at the man and her face changed to an expression of indignation. Following this incident, people executed by guillotine during the Revolution were asked to blink afterward, and witnesses claim that the blinking occurred for up to 30 seconds.
Another often-told tale of demonstrated consciousness following beheading dates to 1905. French physician Dr. Gabriel Beaurieux witnessed the beheading of a man named Languille. He wrote that immediately afterward, "the eyelids and lips ... worked in irregularly rhythmic contractions for about five or six seconds." Dr. Beaurieux called out his name and said that Languille's eyelids "slowly lifted up, without any spasmodic contraction" and that "his pupils focused themselves" [source: Kershaw]. This happened a second time, but the third time Beaurieux spoke, he got no response.
These stories seem to give credence to the idea that it's possible for someone to remain conscious, even for just a few seconds, after being beheaded. However, most modern physicians believe that the reactions described above are actually reflexive twitching of muscles, rather than conscious, deliberate movement. Cut off from the heart (and therefore, from oxygen), the brain immediately goes into a coma and begins to die. According to Dr. Harold Hillman, consciousness is "probably lost within 2-3 seconds, due to a rapid fall of intracranial perfusion of blood" [source: New Scientist].
So while it's not entirely impossible for someone to still be conscious after being decapitated, it's not likely. Hillman also goes on to point out that the so-called painless guillotine is likely anything but. He states that "death occurs due to separation of the brain and spinal cord, after transection of the surrounding tissues. This must cause acute and possibly severe pain." This is one of the reasons why the guillotine, and beheading in general, is no longer an accepted method of execution in many countries with capital punishment.
If your head stays on your shoulders, though, it can still be damaged beyond repair. Next, let's take a look about how long brain damage can last.
Brain Myth 4: Brain Damage Is Always Permanent
Brain damage is an extremely scary thing. For something so mysterious and amazing, the brain can actually be quite fragile and susceptible to a multitude of injuries. Brain damage can be caused by anything from an infection to a car accident, and it essentially means the death of brain cells. To many people, the mere idea of brain damage conjures images of people in persistent vegetative states, or at the very least, permanent physical or mental disability.
But that's not always the case. There are many different types of brain damage, and exactly how it will affect someone depends largely on its location and how severe it is. A mild brain injury, such as a concussion, usually occurs when the brain bounces around inside the skull, resulting in bleeding and tearing. The brain can recover from minor injuries remarkably well; the vast majority of people who experience a mild brain injury don't experience permanent disability.
On the other end of the spectrum, a severe brain injury means that the brain has suffered extensive damage. It sometimes requires surgery to remove built-up blood or relieve pressure. For nearly all patients who live through a severe brain injury, permanent, irreversible damage results.
So what about those in between? Some people with brain damage experience permanent disability but can recover partially from their injury. If neurons are damaged or lost, they can't grow back -- but the synapses, or connections between neurons, can. Essentially, the brain creates new pathways between neurons. In addition, areas of the brain not originally associated with some functions can take over and allow the patient to relearn how to do things. Remember the phenomenon of brain plasticity mentioned in the myth about brain wrinkles? That's how stroke patients, for example, can regain speech and motor skills through therapy.
The important thing to remember is that there are still a lot of unknowns about the brain. When a person is diagnosed with a brain injury, it's not always possible for doctors to know exactly how well someone will be able to recover from the damage. Patients surprise doctors all the time and exceed expectations of what they're able to do days, months and even years later. Not all brain damage is permanent.
Speaking of brain damage, in the next myth, we'll look at the effects that drugs can have on our brains.
Brain Myth 3: You Can Get Holes in Your Brain Through Drug Use
Exactly how different drugs affect your brain is a pretty controversial subject. Some people claim that only the most severe drug use can have any lasting effects, while others believe that the first time you use a drug, you're causing long-term damage. One recent study states that using drugs like marijuana only cause minor memory loss, while another claims that heavy marijuana use can permanently shrink parts of your brain. When it comes to using drugs like cocaine or Ecstasy, some people even believe that you can actually get holes in your brain.
In truth, the only thing that can actually put a hole in your brain is physical trauma to it. Researchers do claim that drugs can cause short-term and long-term changes in the brain. For example, drug use can lower the impact of neurotransmitters (chemicals used to communicate signals in the brain) like dopamine, which is why addicts need more and more of the drug to achieve the same feeling. In addition, changes in the levels of neurotransmitters can result in problems with neuron function. Whether this is reversible or not is also up for debate.
On the other hand, a study in New Scientist from August 2008 states that long-term use of some drugs actually causes certain structures in the brain to grow, resulting in a permanent change. They claim that this is which is why it's so difficult to change the behaviors of addicts.
But although the jury's still out on exactly how different drugs can affect your brain for the long term, we can be reasonably sure of one thing: No drug actually puts holes in your brain.
Next up, let's see exactly what alcohol does to your brain.
Brain Myth 2: Alcohol Kills Brain Cells
Just one observation of a drunken person is enough to convince you that alcohol directly affects the brain. People who drink enough to get drunk often end up with slurred speech and impaired motor skills and judgment, among other side effects. Many of them suffer from headaches, nausea and other unpleasant side effects afterward -- in other words, a hangover. But are a few drinks on the weekend, or even the occasional long drinking session, enough to kill brain cells? What about binge drinking or the frequent, sustained drinking of alcoholics?
Not so much. Even in alcoholics, alcohol use doesn't actually result in the death of brain cells. It can, however, damage the ends of neurons, which are called dendrites. This results in problems conveying messages between the neurons. The cell itself isn't damaged, but the way that it communicates with others is altered. According to researchers such as Roberta J. Pentney, professor of anatomy and cell biology at the University at Buffalo, this damage is mostly reversible.
Alcoholics can develop a neurological disorder called Wernicke-Korsakoff syndrome, which can result in a loss of neurons in some parts of the brain. This syndrome also causes memory problems, confusion, paralysis of the eyes, lack of muscle coordination and amnesia. It can lead to death. However, the disorder isn't caused by the alcohol itself. It's the result of a deficiency of thiamine, an essential B vitamin. Not only are severe alcoholics often malnourished, extreme alcohol consumption can interfere with the body's absorption of thiamine.
So while alcohol doesn't actually kill brain cells, it can still damage your brain if you drink in mass quantities.
How much of your brain did you use while reading this top 10 list? The next myth will explain all.
Brain Myth 1: You Only Use 10 Percent of Your Brain
We've often been told that we only use about 10 percent of our brains. Famous people such as Albert Einstein and Margaret Mead have been quoted as stating a variation of it. This myth is probably one of the most well-known myths about the brain, in part because it's been publicized in the media for what seems like forever. Where did it come from? Many sources point to an American psychologist of the early 1900s named William James, who said that "the average person rarely achieves but a small portion of his or her potential" [source: AARP]. Somehow, that was converted into only using 10 percent of our brain.
This seems really puzzling at first glance. Why would we have the biggest brain in proportion to our bodies of any animal (as discussed in the sixth myth in our list) if we didn't actually use all of it? Many people have jumped on the idea, writing books and selling products that claim to harness the power of the other 90 percent. Believers in psychic abilities such as ESP point to it as proof, saying that people with these abilities have tapped into the rest of their brains.
Here's the thing, though; it's not really true. In addition to those 100 billion neurons, the brain is also full of other types of cells that are continually in use. We can become disabled from damage to just small areas of the brain depending on where it's located, so there's no way that we could function with only 10 percent of our brain in use.
Brain scans have shown that no matter what we're doing, our brains are always active. Some areas are more active at any one time than others, but unless we have brain damage, there is no one part of the brain that is absolutely not functioning. Here's an example. If you're sitting at a table and eating a sandwich, you're not actively using your feet. You're concentrating on bringing the sandwich to your mouth, chewing and swallowing it. But that doesn't mean that your feet aren't working -- there's still activity in them, such as blood flow, even when you're not actually moving them.
These disciplines have been around in some form since ancient times, so you'd think that by now we'd know all there is to know about the brain. Nothing could be further from the truth. After thousands of years of studying and treating every aspect of it, there are still many facets of the brain that remain mysterious. And because the brain is so complex, we tend to simplify information about how it works in order to make it more understandable.
Both of these things put together have resulted in many myths about the brain. Most aren't completely off -- we just haven't quite heard the whole story. Let's look at 10 myths that have been circulating about the brain, starting with, of all things, its color.
Brain Myth 10: Your Brain Is Gray
Have you given any thought to the color of your brain? Maybe not, unless you work in the medical field. We have all colors of the rainbow in our bodies in the form of blood, tissue, bone and other fluids. But you may have seen preserved brains sitting in jars in a classroom or on TV. Most of the time, those brains are a uniform white, gray or even yellowish hue. In actuality, though, the living, pulsing brain currently residing in your skull isn't just a dull, bland gray; it's also white, black and red.
Like many myths about the brain, this one has a grain of truth, because much of the brain is gray. Sometimes the entire brain is referred to as gray matter. Mystery writer Agatha Christie's famous detective Hercule Poirot often spoke of using his "little gray cells." Gray matter exists all throughout the various parts of the brain (as well as in the spinal cord); it consists of different types of cells, such as neurons. However, the brain also contains white matter, which comprises nerve fibers that connect the gray matter.
The black component is called substantia nigra, which is Latin for (you guessed it) "black substance." It's black because of neuromelanin, a specialized type of the same pigment that colors skin and hair, and it's a part of the basal ganglia. Finally, we have red -- and that's thanks to the many blood vessels in the brain. So why are preserved brains chalky looking and dull instead of spongy and colorful? It's due to the fixatives, such as formaldehyde, that keep the brain preserved.
From color, to sound -- the next myth may have you rethinking your musical choices.
Brain Myth 9: Listening to Mozart Makes You Smarter
Don't you just feel cultured when you tune in to a classical music station and take in an opera or a symphony by a great composer like Mozart? Baby Einstein, a company that makes DVDs, videos and other products for babies and toddlers incorporating classical art, music, and poetry, is a million-dollar franchise. Parents buy the products because they believe that exposure to great art (like Baby Mozart DVDs and CDs) can be good for their children's cognitive development. There are even classical music CDs designed to be played to developing fetuses. The idea that listening to classical music can increase your brainpower has become so popular that it's been dubbed "the Mozart effect." So how did this myth start?
In the 1950s, an ear, nose and throat doctor named Albert Tomatis began the trend, claiming success using Mozart's music to help people with speech and auditory disorders. In the 1990s, 36 students in a study at the University of California at Irvine listened to 10 minutes of a Mozart sonata before taking an IQ test. According to Dr. Gordon Shaw, the psychologist in charge of the study, the students' IQ scores went up by about 8 points. The "Mozart effect" was born.
A musician named Dan Campbell trademarked the phrase and created a line of books and CDs based on the concept, and states such as Georgia, Florida and Tennessee set aside money for classical music for babies and other young children. Campbell and others have gone on to assert that listening to Mozart can even improve your health.
However, the original University of California at Irvine study has been controversial in the scientific community. Dr. Frances Rauscher, a researcher involved in the study, stated that they never claimed it actually made anyone smarter; it just increased performance on certain spatial-temporal tasks. Other scientists have been unable to replicate the original results, and there is currently no scientific information to prove that listening to Mozart, or any other classical music, actually makes anyone smarter. Rauscher even said that the money spent by those states might be better spent on musical programs -- there's some evidence to show that learning an instrument improves concentration, self-confidence and coordination.
Mozart certainly can't hurt you, and you might even enjoy it if you give it a try, but you won't get any smarter.
Brain Myth 8: You Get New Brain Wrinkles When You Learn Something
When you think about how your brain looks, you probably picture a roundish, two-lobed gray mass covered in "wrinkles." As humans evolved as a species, our brains grew larger to accommodate all of the higher functions that set us apart from other animals. But in order to keep the brain compact enough to fit into a skull that would actually be in proportion with the rest of our body size, the brain folded in on itself as it grew. If we unfolded all of those ridges and crevices, the brain would be the size of a pillowcase. The ridges are called sulci and the crevices are called gyri. Several of these ridges and crevices even have names, and there are variations in exactly how they look from person to person.
We don't start out with wrinkly brains, however; a fetus early in its development has a very smooth little brain. As the fetus grows, its neurons also grow and migrate to different areas of the brain, creating the sulci and gyri. By the time it reaches 40 weeks, its brain is as wrinkled as yours is (albeit smaller, of course). So we don't develop new wrinkles as we learn. The wrinkles we're born with are the wrinkles we have for life, assuming that our brains remain healthy.
Our brains do change when we learn -- it's just not in the form of additional sulci and gyri. This phenomenon is known as brain plasticity. By studying changes in the brains of animals like rats as they learn tasks, researchers have discovered that synapses (the connections between neurons) and the blood cells that support neurons grow and increase in number. Some believe that we get new neurons when we make new memories, but this hasn't yet been proven in mammalian brains like ours.
If you've ever gotten the feeling that there were hidden messages in commercials, TV shows or movies, the next myth should interest you.
Brain Myth 7: You Can Learn Through Subliminal Messages
The concept of subliminal messages feeds into our suspicions about what the government, big corporations and media are really trying to tell us. A subliminal message (meaning, below "limen," or our conscious perception threshold) is a message embedded into images or sound meant to penetrate into our subconscious and influence our behavior. The first person to coin the term was James Vicary, a market researcher. In 1957, Vicary stated that he inserted messages into a showing of a movie in New Jersey. The messages, which flashed for 1/3000th of a second, told moviegoers to drink Coca-Cola and eat popcorn.
According to Vicary, Coke sales in the theater increased by more than 18 percent and popcorn sales by more than 57 percent, proving that his subliminal messages worked. Books published in the late 1950s and early 1970s outlined how advertisers could use techniques like Vicary's to convince consumers to buy their products. Some radio and TV commercials included subliminal messages, but many networks and professional associations banned them. In 1974, the FCC banned the use of subliminal advertising.
But did the messages work? Turns out, Vicary actually lied about the results of his study. Subsequent studies, including one which flashed the message "Call now" during a broadcast on a Canadian TV station, had no effect on viewers. The infamous 1990s Judas Priest trial, in which the families of two boys who committed suicide claimed that a song told the boys to do it, ended with the judge stating that there was no scientific evidence in their favor. Yet some people still claim that music, as well as advertisements, contains hidden messages.
So listening to those self-help tapes while you sleep probably can't hurt you, but they aren't likely to help you quit smoking, either.
When it comes to the human brain versus other animals' brains, does size matter? Check out our next myth to find out.
Brain Myth 6: The Human Brain Is the Biggest Brain
Many animals can use their brains to do some of the things that humans can do, such as finding creative ways to solve problems, exhibiting self-awareness, showing empathy toward others and learning how to use tools. But although scientists can't agree on a single definition of what makes a person intelligent, they do generally agree that humans are the most intelligent creatures on Earth. In our "bigger is better" society, then, it might stand to reason that humans should have the biggest brains of all animals, because we're the smartest. Well, not exactly.
The average adult human brain weighs about 3 pounds (1,361 grams). The dolphin -- a very intelligent animal -- also has a brain that weighs about 3 pounds on average. But a sperm whale, not generally considered to be as intelligent as a dolphin, has a brain that weighs about 17 pounds (7,800 grams). On the small end of the scale, a beagle's brain is about 2.5 ounces (72 grams), and an orangutan's brain is about 13 ounces (370 grams). Both dogs and orangutans are pretty smart animals, but they have small brains. A bird like a sparrow has a brain that weighs less than half an ounce (1 gram).
You may notice something important in all of those comparisons. An average dolphin's body weighs about 350 pounds (158.8 kilograms), while a sperm whale can weigh as much as 13 tons. In general, the larger the animal, the larger the skull, and therefore, the larger the brain. Beagles are fairly small dogs, at about 25 pounds (11.3 kg) maximum, so it stands to reason that their brains would also be smaller. The relationship between brain size and intelligence isn't really about the actual weight of the brain; it's about the ratio of brain weight to the entire body weight. For humans, that ratio is about 1-to-50. For most other mammals, it's 1-to-180, and for birds, it's 1-to-220. The brain takes up more weight in a human than it does in other animals.
Intelligence also has to do with the different components of the brain. Mammals have very large cerebral cortexes, unlike birds, fish or reptiles. The cerebellum in mammals houses the cerebral hemispheres, which are responsible for higher functions like memory, communication and thinking. Humans have the largest cerebral cortex of all mammals, relative to the size of their brains.
Heads up; we're looking at a grislier brain myth next.
Brain Myth 5: Your Brain Stays Active After You Get Decapitated
At one time in history, decapitation was one of the preferred methods of execution, in part thanks to the guillotine. Although many countries that execute criminals have dispatched with the method, it's still performed by certain governments, terrorists and others. There's nothing more final than the severing of one's head. The guillotine came about because of the desire for a quick, relatively humane death. But how quick is it? If your head were cut off, would you still be able to see or otherwise move it, even for just a few seconds?
This concept perhaps first appeared during the French Revolution, the very time period in which the guillotine was created. On July 17, 1793, a woman named Charlotte Corday was executed by guillotine for the assassination of Jean-Paul Marat, a radical journalist, politician and revolutionary. Marat was well-liked for his ideas and the mob awaiting the guillotine was eager to see Corday pay. After the blade dropped and Corday's head fell, one of the executioner's assistants picked it up and slapped its cheek. According to witnesses, Corday's eyes turned to look at the man and her face changed to an expression of indignation. Following this incident, people executed by guillotine during the Revolution were asked to blink afterward, and witnesses claim that the blinking occurred for up to 30 seconds.
Another often-told tale of demonstrated consciousness following beheading dates to 1905. French physician Dr. Gabriel Beaurieux witnessed the beheading of a man named Languille. He wrote that immediately afterward, "the eyelids and lips ... worked in irregularly rhythmic contractions for about five or six seconds." Dr. Beaurieux called out his name and said that Languille's eyelids "slowly lifted up, without any spasmodic contraction" and that "his pupils focused themselves" [source: Kershaw]. This happened a second time, but the third time Beaurieux spoke, he got no response.
These stories seem to give credence to the idea that it's possible for someone to remain conscious, even for just a few seconds, after being beheaded. However, most modern physicians believe that the reactions described above are actually reflexive twitching of muscles, rather than conscious, deliberate movement. Cut off from the heart (and therefore, from oxygen), the brain immediately goes into a coma and begins to die. According to Dr. Harold Hillman, consciousness is "probably lost within 2-3 seconds, due to a rapid fall of intracranial perfusion of blood" [source: New Scientist].
So while it's not entirely impossible for someone to still be conscious after being decapitated, it's not likely. Hillman also goes on to point out that the so-called painless guillotine is likely anything but. He states that "death occurs due to separation of the brain and spinal cord, after transection of the surrounding tissues. This must cause acute and possibly severe pain." This is one of the reasons why the guillotine, and beheading in general, is no longer an accepted method of execution in many countries with capital punishment.
If your head stays on your shoulders, though, it can still be damaged beyond repair. Next, let's take a look about how long brain damage can last.
Brain Myth 4: Brain Damage Is Always Permanent
Brain damage is an extremely scary thing. For something so mysterious and amazing, the brain can actually be quite fragile and susceptible to a multitude of injuries. Brain damage can be caused by anything from an infection to a car accident, and it essentially means the death of brain cells. To many people, the mere idea of brain damage conjures images of people in persistent vegetative states, or at the very least, permanent physical or mental disability.
But that's not always the case. There are many different types of brain damage, and exactly how it will affect someone depends largely on its location and how severe it is. A mild brain injury, such as a concussion, usually occurs when the brain bounces around inside the skull, resulting in bleeding and tearing. The brain can recover from minor injuries remarkably well; the vast majority of people who experience a mild brain injury don't experience permanent disability.
On the other end of the spectrum, a severe brain injury means that the brain has suffered extensive damage. It sometimes requires surgery to remove built-up blood or relieve pressure. For nearly all patients who live through a severe brain injury, permanent, irreversible damage results.
So what about those in between? Some people with brain damage experience permanent disability but can recover partially from their injury. If neurons are damaged or lost, they can't grow back -- but the synapses, or connections between neurons, can. Essentially, the brain creates new pathways between neurons. In addition, areas of the brain not originally associated with some functions can take over and allow the patient to relearn how to do things. Remember the phenomenon of brain plasticity mentioned in the myth about brain wrinkles? That's how stroke patients, for example, can regain speech and motor skills through therapy.
The important thing to remember is that there are still a lot of unknowns about the brain. When a person is diagnosed with a brain injury, it's not always possible for doctors to know exactly how well someone will be able to recover from the damage. Patients surprise doctors all the time and exceed expectations of what they're able to do days, months and even years later. Not all brain damage is permanent.
Speaking of brain damage, in the next myth, we'll look at the effects that drugs can have on our brains.
Brain Myth 3: You Can Get Holes in Your Brain Through Drug Use
Exactly how different drugs affect your brain is a pretty controversial subject. Some people claim that only the most severe drug use can have any lasting effects, while others believe that the first time you use a drug, you're causing long-term damage. One recent study states that using drugs like marijuana only cause minor memory loss, while another claims that heavy marijuana use can permanently shrink parts of your brain. When it comes to using drugs like cocaine or Ecstasy, some people even believe that you can actually get holes in your brain.
In truth, the only thing that can actually put a hole in your brain is physical trauma to it. Researchers do claim that drugs can cause short-term and long-term changes in the brain. For example, drug use can lower the impact of neurotransmitters (chemicals used to communicate signals in the brain) like dopamine, which is why addicts need more and more of the drug to achieve the same feeling. In addition, changes in the levels of neurotransmitters can result in problems with neuron function. Whether this is reversible or not is also up for debate.
On the other hand, a study in New Scientist from August 2008 states that long-term use of some drugs actually causes certain structures in the brain to grow, resulting in a permanent change. They claim that this is which is why it's so difficult to change the behaviors of addicts.
But although the jury's still out on exactly how different drugs can affect your brain for the long term, we can be reasonably sure of one thing: No drug actually puts holes in your brain.
Next up, let's see exactly what alcohol does to your brain.
Brain Myth 2: Alcohol Kills Brain Cells
Just one observation of a drunken person is enough to convince you that alcohol directly affects the brain. People who drink enough to get drunk often end up with slurred speech and impaired motor skills and judgment, among other side effects. Many of them suffer from headaches, nausea and other unpleasant side effects afterward -- in other words, a hangover. But are a few drinks on the weekend, or even the occasional long drinking session, enough to kill brain cells? What about binge drinking or the frequent, sustained drinking of alcoholics?
Not so much. Even in alcoholics, alcohol use doesn't actually result in the death of brain cells. It can, however, damage the ends of neurons, which are called dendrites. This results in problems conveying messages between the neurons. The cell itself isn't damaged, but the way that it communicates with others is altered. According to researchers such as Roberta J. Pentney, professor of anatomy and cell biology at the University at Buffalo, this damage is mostly reversible.
Alcoholics can develop a neurological disorder called Wernicke-Korsakoff syndrome, which can result in a loss of neurons in some parts of the brain. This syndrome also causes memory problems, confusion, paralysis of the eyes, lack of muscle coordination and amnesia. It can lead to death. However, the disorder isn't caused by the alcohol itself. It's the result of a deficiency of thiamine, an essential B vitamin. Not only are severe alcoholics often malnourished, extreme alcohol consumption can interfere with the body's absorption of thiamine.
So while alcohol doesn't actually kill brain cells, it can still damage your brain if you drink in mass quantities.
How much of your brain did you use while reading this top 10 list? The next myth will explain all.
Brain Myth 1: You Only Use 10 Percent of Your Brain
We've often been told that we only use about 10 percent of our brains. Famous people such as Albert Einstein and Margaret Mead have been quoted as stating a variation of it. This myth is probably one of the most well-known myths about the brain, in part because it's been publicized in the media for what seems like forever. Where did it come from? Many sources point to an American psychologist of the early 1900s named William James, who said that "the average person rarely achieves but a small portion of his or her potential" [source: AARP]. Somehow, that was converted into only using 10 percent of our brain.
This seems really puzzling at first glance. Why would we have the biggest brain in proportion to our bodies of any animal (as discussed in the sixth myth in our list) if we didn't actually use all of it? Many people have jumped on the idea, writing books and selling products that claim to harness the power of the other 90 percent. Believers in psychic abilities such as ESP point to it as proof, saying that people with these abilities have tapped into the rest of their brains.
Here's the thing, though; it's not really true. In addition to those 100 billion neurons, the brain is also full of other types of cells that are continually in use. We can become disabled from damage to just small areas of the brain depending on where it's located, so there's no way that we could function with only 10 percent of our brain in use.
Brain scans have shown that no matter what we're doing, our brains are always active. Some areas are more active at any one time than others, but unless we have brain damage, there is no one part of the brain that is absolutely not functioning. Here's an example. If you're sitting at a table and eating a sandwich, you're not actively using your feet. You're concentrating on bringing the sandwich to your mouth, chewing and swallowing it. But that doesn't mean that your feet aren't working -- there's still activity in them, such as blood flow, even when you're not actually moving them.
Selasa, Agustus 26, 2008
Ini dia syarat Kampanye via SMS
Heru Sutadi, Anggota Badan Regulasi Telekomunikasi Indonesia (BRTI), mengatakan bahwa parpol peserta Pemilu 2009 sudah diperbolehkan melakukan kampanye via SMS. Ada lima syarat yang harus dipenuhi jika hendak berkampanye lewat SMS
Apa saja syarat-syarat itu? ini dia…
1. Kampanye harus mengikuti tata aturan kampanye sesuai Undang-Undang No. 10/2008 tentang Pemilu.
2. Operator wajib menjaga kerahasiaan data pengguna ponsel sehingga baik parpol, capres,cawapres dan calon anggota DPD tidak boleh melakukan push sms ke semua pelanggan. Melainkan hanya ke konstituen atau simpatisan yang terdaftar.
3. Operator harus adil memberikan kesempatan yang sama kepada seluruh parpol dan calonnya
4. Kerjasama dengan parpol atau capres/cawapres dan calon anggota DPD harus dilakukan dengan pelaksana kampanye yang terdaftar di KPU.
5. Untuk menjaga kualitas layanan, frekuensi pengiriman akan dibatasi
*) dikutip dari Detikinet.
Apa saja syarat-syarat itu? ini dia…
1. Kampanye harus mengikuti tata aturan kampanye sesuai Undang-Undang No. 10/2008 tentang Pemilu.
2. Operator wajib menjaga kerahasiaan data pengguna ponsel sehingga baik parpol, capres,cawapres dan calon anggota DPD tidak boleh melakukan push sms ke semua pelanggan. Melainkan hanya ke konstituen atau simpatisan yang terdaftar.
3. Operator harus adil memberikan kesempatan yang sama kepada seluruh parpol dan calonnya
4. Kerjasama dengan parpol atau capres/cawapres dan calon anggota DPD harus dilakukan dengan pelaksana kampanye yang terdaftar di KPU.
5. Untuk menjaga kualitas layanan, frekuensi pengiriman akan dibatasi
*) dikutip dari Detikinet.
Jumat, Agustus 22, 2008
How to Avoid Hypothermia
The human body is somewhat like that perfect bowl of porridge in "Goldilocks and the Three Bears." It's not too hot, not too cold, but just right.
Our bodies maintain internal body temperatures that allow our insides to keep on cooking without burning up or slowing down -- usually around 98.6 degrees Fahrenheit (37 degrees Celsius). There's even a part of our brain called the hypothalamus that regulates this internal heat to keep everything running smoothly
But when that core temperature of major organs drops down to 95 degrees or lower, it is called hypothermia. Just like when you have a high fever, hypothermia can slow your body and possibly lead to death.
When it comes to our bodies, a lot depends on heat. Heat is the byproduct of biochemical reactions within our bodies. The food and beverages we consume are just like the wood and kindling that make a fire. Our bodies gain energy from food, and that energy pumps our hearts, grows our hair and helps our digestive system break that food down into usable units. This process is called metabolism.
Think about all of the internal processes that take place when you run. It requires energy to move so many parts of your body at the same time. When all those parts crank up, we burn up energy, producing heat.
In the cold, our bodies strive to retain as much heat, or energy, as possible. In many parts of the body, blood vessels in our skin tissue constrict, or tighten up. This tightening helps keeps blood away from the cold outer layer of the body and helps circulate warmer blood to our core areas. This tightening is also why you may feel stiff after being in the cold for a long time.
However, areas with large blood vessels, particularly around the head, neck, chest and groin, are more susceptible to heat loss because those blood vessels don't constrict as effectively as the smaller ones near the skin. That's why proper winter attire includes a hat, scarf and coat.With all of these internal actions and reactions taking place within the body, what can we do to protect our core temperature and defend ourselves from hypothermia?
How to Avoid Death from Hypothermia
Nearly 700 people in the United States die each year from hypothermia [source: Mayo Clinic]. Hypothermia is a silent killer because once your body temperature drops below 95 degrees, you lose awareness of the cold and become disoriented because less oxygen reaches the brain. For that reason, take special precautions if you're alone in the cold. You may not be aware that your body is in peril.
Hypothermia Risk GroupsInfants and the elderly are the most at risk for developing hypothermia. Babies do not preserve body heat as well as adults, and the elderly may not have a high enough metabolism to stay warm. For both, it is important that their bedrooms not be too cold and that they are regularly monitored during the winter.
Groups of people should look after each other for the signs of hypothermia discussed in the previous section. If someone does appear hypothermic, there are a number of things that you can do to prevent that person from dying. In mild to moderate cases, the body can re-warm at a rate of 3.6 degrees per hour.
To start that warming process, first move into shelter. If there is nowhere to go indoors, at least move the person out of the wind, since wind can speed up hypothermia. Remove any wet clothing and replace them with dry blankets or even newspaper.
Getty ImagesNavy Seals huddle for warmth during training. Removing clothes and sharing body heat can keep people warm.
For people with mild or moderate hypothermia, some food and beverages may be helpful. Warm, sweet liquids, such as diluted gelatin mix or hot chocolate will give the body quick energy boosts to help it produce heat. Proteins, fats and carbohydrates in the form of trail mix and granola can also stimulate the metabolism. Do not give them alcohol or caffeine.
In more severe cases, getting a person out of any wet clothes and into a hypothermic wrap is essential. There should be several layers of insulation between the wrap and the cold ground. A hypothermic wrap covers every part of the body with as few open spaces as possible. A sleeping bag or multiple blankets can serve as hypothermic wraps, as long as the person is completely protected from the cold.
Additionally, extra clothing or blankets should be applied to the neck, groin, armpits and chest to protect major arteries. Sharing body heat by removing your clothes and getting into the wrap with the person may also prove beneficial, except in very severe cases. Also, do not apply heat directly to the skin or give the person a massage because it can circulate the colder blood near the skin to the core, shocking the body.
Johner/Getty ImagesHypothermic wraps cover people's bodies entirely while being insulated from cold ground.
CPR is another option if a hypothermic person's skin has turned blue, and you can't feel a pulse. But only do this if you are properly trained. If you stimulate the body too much with CPR, it can overexcite the heart and lead to cardiac arrest.
If possible, call 911 to get someone with severe hypothermia to a hospital. A doctor may hook up a person with hypothermia to an IV to put warming fluids directly into the body. He or she may also perform a procedure called hemodialysis, which takes the patient's blood out of the body, runs it through a warming mechanism, and returns it.
Our bodies maintain internal body temperatures that allow our insides to keep on cooking without burning up or slowing down -- usually around 98.6 degrees Fahrenheit (37 degrees Celsius). There's even a part of our brain called the hypothalamus that regulates this internal heat to keep everything running smoothly
But when that core temperature of major organs drops down to 95 degrees or lower, it is called hypothermia. Just like when you have a high fever, hypothermia can slow your body and possibly lead to death.
When it comes to our bodies, a lot depends on heat. Heat is the byproduct of biochemical reactions within our bodies. The food and beverages we consume are just like the wood and kindling that make a fire. Our bodies gain energy from food, and that energy pumps our hearts, grows our hair and helps our digestive system break that food down into usable units. This process is called metabolism.
Think about all of the internal processes that take place when you run. It requires energy to move so many parts of your body at the same time. When all those parts crank up, we burn up energy, producing heat.
In the cold, our bodies strive to retain as much heat, or energy, as possible. In many parts of the body, blood vessels in our skin tissue constrict, or tighten up. This tightening helps keeps blood away from the cold outer layer of the body and helps circulate warmer blood to our core areas. This tightening is also why you may feel stiff after being in the cold for a long time.
However, areas with large blood vessels, particularly around the head, neck, chest and groin, are more susceptible to heat loss because those blood vessels don't constrict as effectively as the smaller ones near the skin. That's why proper winter attire includes a hat, scarf and coat.With all of these internal actions and reactions taking place within the body, what can we do to protect our core temperature and defend ourselves from hypothermia?
How to Avoid Death from Hypothermia
Nearly 700 people in the United States die each year from hypothermia [source: Mayo Clinic]. Hypothermia is a silent killer because once your body temperature drops below 95 degrees, you lose awareness of the cold and become disoriented because less oxygen reaches the brain. For that reason, take special precautions if you're alone in the cold. You may not be aware that your body is in peril.
Hypothermia Risk GroupsInfants and the elderly are the most at risk for developing hypothermia. Babies do not preserve body heat as well as adults, and the elderly may not have a high enough metabolism to stay warm. For both, it is important that their bedrooms not be too cold and that they are regularly monitored during the winter.
Groups of people should look after each other for the signs of hypothermia discussed in the previous section. If someone does appear hypothermic, there are a number of things that you can do to prevent that person from dying. In mild to moderate cases, the body can re-warm at a rate of 3.6 degrees per hour.
To start that warming process, first move into shelter. If there is nowhere to go indoors, at least move the person out of the wind, since wind can speed up hypothermia. Remove any wet clothing and replace them with dry blankets or even newspaper.
Getty ImagesNavy Seals huddle for warmth during training. Removing clothes and sharing body heat can keep people warm.
For people with mild or moderate hypothermia, some food and beverages may be helpful. Warm, sweet liquids, such as diluted gelatin mix or hot chocolate will give the body quick energy boosts to help it produce heat. Proteins, fats and carbohydrates in the form of trail mix and granola can also stimulate the metabolism. Do not give them alcohol or caffeine.
In more severe cases, getting a person out of any wet clothes and into a hypothermic wrap is essential. There should be several layers of insulation between the wrap and the cold ground. A hypothermic wrap covers every part of the body with as few open spaces as possible. A sleeping bag or multiple blankets can serve as hypothermic wraps, as long as the person is completely protected from the cold.
Additionally, extra clothing or blankets should be applied to the neck, groin, armpits and chest to protect major arteries. Sharing body heat by removing your clothes and getting into the wrap with the person may also prove beneficial, except in very severe cases. Also, do not apply heat directly to the skin or give the person a massage because it can circulate the colder blood near the skin to the core, shocking the body.
Johner/Getty ImagesHypothermic wraps cover people's bodies entirely while being insulated from cold ground.
CPR is another option if a hypothermic person's skin has turned blue, and you can't feel a pulse. But only do this if you are properly trained. If you stimulate the body too much with CPR, it can overexcite the heart and lead to cardiac arrest.
If possible, call 911 to get someone with severe hypothermia to a hospital. A doctor may hook up a person with hypothermia to an IV to put warming fluids directly into the body. He or she may also perform a procedure called hemodialysis, which takes the patient's blood out of the body, runs it through a warming mechanism, and returns it.
Kamis, Agustus 21, 2008
Tips for Avoiding Shark Attacks
Don't let your summer dreams get ripped at the seams. At the beach, follow these tips for avoiding shark attacks.
Don't swim alone.
Don't swim before dawn or after dusk during prime shark feeding times.
Don't wear anything shiny or metallic that could attract sharks.
Don't splash excessively.
Don't bring your pets into the water with you.
Stay away from drop-off areas where sharks may congregate.
If you're bleeding anywhere, get out of the water.
If you see a shark, don't provoke it.
Don't swim near active fishing docks.
Don't wear high-contrast clothing.
Don't swim alone.
Don't swim before dawn or after dusk during prime shark feeding times.
Don't wear anything shiny or metallic that could attract sharks.
Don't splash excessively.
Don't bring your pets into the water with you.
Stay away from drop-off areas where sharks may congregate.
If you're bleeding anywhere, get out of the water.
If you see a shark, don't provoke it.
Don't swim near active fishing docks.
Don't wear high-contrast clothing.
Can playing dead help save me from a shark attack?
Let's say you're camping in the woods and wake up to find a bear at your campsite. Unless the bear acts aggressively, dropping to your knees and playing dead can cause it to lose interest in you and amble on.
What if a similar situation happened in the ocean? While doggy paddling around, you spy a shark nearby. Do you go limp and hope for the best? To answer that question, let's examine how sharks approach and attack humans.
Unlike popular beliefs about sharks as vicious man-eaters, the infamous fish usually make contact with humans out of curiosity rather than predation [source: Parker]. For instance, if you're thrashing around in the water or have reflective clothing or jewelry on, a shark may mistake you for a fellow fish or seal. Fueled by this inquisitiveness, sharks often perform hit-and-runs, which means they take a bite -- rarely lethal -- and swim away [source: Florida Museum of Natural History]. This happens particularly in shallower depths.
The real danger comes with sneak attacks and bump-and-bites. You won't have any warning signs for a shark sneak attack, hence the name [source: Florida Museum of Natural History]. With bump-and-bites, which often occur in deeper waters, sharks circle and run into you before going in for a bite.
When you notice a shark heading your way, it's in your best interest not to play dead. Instead, get those arms and legs pumping and try to swim away as quickly and quietly as you can before it takes a nibble.
If you're alone in the water, playing dead isn't going to help because sharks prefer to go for more defenseless prey to conserve energy. If one bites, it's time to fight. Hit a shark in the nose, eyes and gills to stun it and scare it away. Since blood will attract more sharks, find dry land as a fast as possible to reduce the chance of repeat attacks.
In one specific survival situation, playing dead is your only viable option.
On July 30, 1945, during World War II, the U.S.S. Indianapolis sank in the Philippine Sea near Guam. Nearly 900 sailors were left stranded in the water for four days without help. Soon after the sinking, sharks began to attack many of the men. When rescue arrived, only 316 people remained alive, although it isn't clear how many of those victims died from shark attacks.
In rare situations like this one, playing dead could work to your advantage. If sharks are in a feeding frenzy around you, they may ignore your fresh meat and continue biting at others. It may sound inhuman not to try to fight off a swarm of sharks attacking dozens of people around you in the water, but it may be your only hope for survival.
Sharks have a unique sense called electroreception. In rescue scenarios, sharks will continue to go after a wounded person rather than the fresh meat of the rescuer because it is physiologically attracted to blood. Electroreception allows sharks to detect minute changes in the electricity conducted through salt water. Adding blood to salt water alters the surrounding electricity, setting off the sharks' electroreception, which draws it back to the wounded victim.
Thrashing around in the water is also known to attract sharks. If you float calmly while surrounded by flailing, splashing people, sharks may ignore you and go for the more obvious targets. In addition, stay alert to the warning signs of an impending chomp. A hunched back, lowered pectoral fins and zigzagging motion are red flags that you look like a tasty piece of meat [source: Burgess].
Of course, if you have a chance to escape water, do so as fast as you can. And if a shark bites you, hit it back on its nose, gills or eyes.
What if a similar situation happened in the ocean? While doggy paddling around, you spy a shark nearby. Do you go limp and hope for the best? To answer that question, let's examine how sharks approach and attack humans.
Unlike popular beliefs about sharks as vicious man-eaters, the infamous fish usually make contact with humans out of curiosity rather than predation [source: Parker]. For instance, if you're thrashing around in the water or have reflective clothing or jewelry on, a shark may mistake you for a fellow fish or seal. Fueled by this inquisitiveness, sharks often perform hit-and-runs, which means they take a bite -- rarely lethal -- and swim away [source: Florida Museum of Natural History]. This happens particularly in shallower depths.
The real danger comes with sneak attacks and bump-and-bites. You won't have any warning signs for a shark sneak attack, hence the name [source: Florida Museum of Natural History]. With bump-and-bites, which often occur in deeper waters, sharks circle and run into you before going in for a bite.
When you notice a shark heading your way, it's in your best interest not to play dead. Instead, get those arms and legs pumping and try to swim away as quickly and quietly as you can before it takes a nibble.
If you're alone in the water, playing dead isn't going to help because sharks prefer to go for more defenseless prey to conserve energy. If one bites, it's time to fight. Hit a shark in the nose, eyes and gills to stun it and scare it away. Since blood will attract more sharks, find dry land as a fast as possible to reduce the chance of repeat attacks.
In one specific survival situation, playing dead is your only viable option.
On July 30, 1945, during World War II, the U.S.S. Indianapolis sank in the Philippine Sea near Guam. Nearly 900 sailors were left stranded in the water for four days without help. Soon after the sinking, sharks began to attack many of the men. When rescue arrived, only 316 people remained alive, although it isn't clear how many of those victims died from shark attacks.
In rare situations like this one, playing dead could work to your advantage. If sharks are in a feeding frenzy around you, they may ignore your fresh meat and continue biting at others. It may sound inhuman not to try to fight off a swarm of sharks attacking dozens of people around you in the water, but it may be your only hope for survival.
Sharks have a unique sense called electroreception. In rescue scenarios, sharks will continue to go after a wounded person rather than the fresh meat of the rescuer because it is physiologically attracted to blood. Electroreception allows sharks to detect minute changes in the electricity conducted through salt water. Adding blood to salt water alters the surrounding electricity, setting off the sharks' electroreception, which draws it back to the wounded victim.
Thrashing around in the water is also known to attract sharks. If you float calmly while surrounded by flailing, splashing people, sharks may ignore you and go for the more obvious targets. In addition, stay alert to the warning signs of an impending chomp. A hunched back, lowered pectoral fins and zigzagging motion are red flags that you look like a tasty piece of meat [source: Burgess].
Of course, if you have a chance to escape water, do so as fast as you can. And if a shark bites you, hit it back on its nose, gills or eyes.
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