Archive for January, 2016
US Military Wants Smaller and More Stable Atomic Clocks
The U.S. military wants you … to design a better atomic clock.
The Defense Advanced Research Projects Agency (DARPA), the branch of the U.S. Department of Defense tasked with developing new technologies for the military, recently announced a new program called Atomic Clocks with Enhanced Stability (ACES). The program aims to design anatomic clock that is 1,000 times more stable than current models, which are so precise that they arecapable of maintaining perfect time for billions of years, neither gaining nor losing 1 second during that time.
Atomic clocks are used to keep track of time in places where a tiny fraction of a second makes a huge difference. For instance, telecommunications towers employ them to synchronize data packets to within microseconds; if their clocks were off, the bits would pile up like cars in a traffic jam, and calls would get dropped. GPS satellites use them to time the signals that bounce between the satellites and the receivers to pinpoint specific locations. [5 of the Most Precise Clocks Ever Made]
“Every nanosecond you’re off, you’re out by 3 feet [0.9 meters],” said John Kitching, a group leader at the National Institute of Standards and Technology and an expert on small atomic clocks. “So, if you’re out [by a] microsecond, you’re off by a mile.”
Ordinarily, atomic clocks resynchronize regularly — for example, cellphone towers will check their clocks against those in GPS satellitesand adjust for any discrepancies. But they can’t do that if the GPS signal gets lost. GPS signals are weak enough that they can be jammed or interfered with, sometimes even inadvertently by a passerby with a cellphone, Kitching said. This could cause a satellite to go offline, either by accident or design. You can even lose a GPS signal by walking into a building or a canyon. (You may have noticed that when you’re inside a building, your phone’s mapping app is usually using the local Wi-Fi.)
This is one reason the military wants to build more stable clocks — they want ones that stay synchronized even if they are out of contact with GPS systems for extended periods of time.
As part of the ACES program, the Department of Defense wants to have atomic clocks that are small enough to fit inside a wallet and that can run on a quarter of a watt. That second parameter will likely be the bigger challenge, Kitching told Live Science.
“The smallest atomic clocks fit into a deck of cards, but they run on about 10 watts,” he said. “That’s not much if you’re plugging it into a wall, but an ordinarylithium-ion battery will run for about 10 minutes.”
Power is such a problem because of the way atomic clocks work, Kitching said. In an atomic clock, the “pendulum” is an atom, usually of an alkali metal like rubidium or cesium. The metal is put into a tiny vacuum chamber, surrounded by a piece of silicon. Then, both are sandwiched between pieces of glass. The metal is warmed up, and some of its atoms separate, forming a vapor.
Then, a laser beam is fired through the metal. Lasers operate at a specific frequency, though they can be tuned up or down a small amount, he added. The laser beam hits the atoms, which vibrate at a specific frequency. Meanwhile, a photodetector picks up the beam as it exits the vacuum chamber. As the laser is tuned, the light starts to match the frequency of the atoms’ vibrations, reaching a state called resonance. When it matches up, the photodetector picks up a stronger signal and turns that into an electrical pulse. The pulse goes to an oscillator that feeds back to the laser to keep it precisely tuned. Kitching said. All this takes power to run. [Video: How to Build the Most Accurate Atomic Clocks]
Even the most precise atomic clocks will drift, and the most sophisticated ones in labs like the NIST are operated at extremely low temperatures and are cooled with room-size laser beams. Both of these factors mean it will be challenging to make atomic clocks wallet-size and less power-hungry, said Kitching.
Robert Lutwak, DARPA’s program manager for the atomic clock project, agreed that fulfilling all the requirements set out by the agency will not be easy. “NIST has a fairly unique mission — to demonstrate the highest possible accuracy in a laboratory setting. As such, they “pull out all of the stops” to achieve the optimum performance without regards for cost, size, weight, or power, and without need for robust continuous operation over time, temperature, vibration, shock, or other real-world environments,” he told Live Science in an email.
The ACES program will have a budget of up to $50 million and will include three phases, according to DARPA. The teams chosen to take part in the first phase of the program will build their clocks in a laboratory and have to show that the parts operate together as an atomic clock with better stability than existing models. The teams chosen to continue the program will be asked to pack their clocks into a space smaller than 2 cubic inches (33 cubic centimeters). The final stage will involve demonstrating that the atomic clock can fit into a space less than 3 cubic inches (49 cubic cm), along with all the associated electronics.
An earlier DARPA program that lasted from 2000 to 2009 managed to shrink atomic clocks by a factor of 100 and create ones that were stable by a factor of 1 in 10 billion each second (meaning they will drift one second every 317 years). “The goals of the ACES program are to advance these by at least an order of magnitude,” Lutwak said.
On Feb. 1, DARPA will host an event to provide additional details about the ACES program.
Circulatory System: Facts, Function & Diseases
The circulatory system is a vast network of organs and vessels that is responsible for the flow of blood, nutrients, hormones, oxygen and other gases to and from cells. Without the circulatory system, the body would not be able to fight disease or maintain a stable internal environment — such as proper temperature and pH — known as homeostasis.
Description of the circulatory system
While many view the circulatory system, also known as the cardiovascular system, as simply a highway for blood, it is made up of three independent systems that work together: the heart (cardiovascular); lungs (pulmonary); and arteries, veins, coronary and portal vessels (systemic), according to the U.S National Library of Medicine (NLM).
In the average human, about 2,000 gallons (7,572 liters) of blood travel daily through about 60,000 miles (96,560 kilometers) of blood vessels, according to theArkansas Heart Hospital. An average adult has 5 to 6 quarts (4.7 to 5.6 liters) of blood, which is made up of plasma, red blood cells, white blood cells and platelets. In addition to blood, the circulatory system moves lymph, which is a clear fluid that helps rid the body of unwanted material.
The heart, blood, and blood vessels make up the cardiovascular component of the circulatory system. It includes the pulmonary circulation, a “loop” through the lungs where blood is oxygenated. It also incorporates the systemic circulation, which runs through the rest of the body to provide oxygenated blood, according to NLM.
The pulmonary circulatory system sends oxygen-depleted blood away from the heart through the pulmonary artery to the lungs and returns oxygenated blood to the heart through the pulmonary veins, according to the Mayo Clinic.
Oxygen-deprived blood enters the right atrium of the heart and flows through the tricuspid valve (right atrioventricular valve) into the right ventricle. From there it is pumped through the pulmonary semilunar valve into the pulmonary artery on its way to the lungs. When it gets to the lungs, carbon dioxide is released from the blood and oxygen is absorbed. The pulmonary vein sends the oxygen-rich blood back to the heart, according to NLM.
The systemic circulation is the portion of the circulatory system is the network of veins, arteries and blood vessels that transports blood from heart, services the body’s cells and then re-enters the heart, the Mayo Clinic noted.
Diseases of the circulatory system
According to the American Heart Association, cardiovascular disease is the leading cause of death in the United States. Because of its vastness and critical nature, it is one of the systems of the body most prone to disease.
One of the most common diseases of the circulatory system is arteriosclerosis, in which the fatty deposits in the arteries causes the walls to stiffen and thicken the walls. According to the Mayo Clinic, the causes are a buildup of fat, cholesterol and other material in the artery walls. This can restrict blood flow or in severe cases stop it all together, resulting in a heart attack or stroke.
Stroke involves blockage of the blood vessels to the brain and is another major condition of the circulatory system, according to Mitchell Weinberg of the North Shore-LIJ Health System. “Risk factors include smoking, diabetes and high cholesterol,” he noted.
Another circulatory disease, hypertension — commonly called high blood pressure — causes the heart to work harder and can lead to such complications as a heart attack, a stroke, or kidney failure, the NLM noted.
An aortic aneurysm occurs when the aorta is damaged and starts to bulge or eventually tear, which can cause severe internal bleeding. This weakness can be present at birth or the result of atherosclerosis, obesity, high blood pressure or a combination of these conditions, according to Weinberg.
Peripheral arterial disease (also known as PAD) typically involves areas of narrowing or blockage within an artery, according to Jay Radhakrishnan, an interventional radiologist in Houston, Texas. In addition, chronic venous insufficiency (also known as CVI) involves areas reflux (or backward flow) within the superficial veins of the lower extremities.
PAD is diagnosed with noninvasive testing including ultrasound, CT scan, and/or MRI. Ultrasound is the least expensive of these methods, but also gives the least amount of detail, as CT and MRI show a much higher degree of anatomic detail when identifying areas of narrowing/blockage within an artery. CVI is diagnosed with ultrasound as the venous reflux can be measured accurately by ultrasound, which ultimately guides treatment.
Study of the circulatory system
Cardiologists are specialists who are certified to diagnose, treat and prevent disease of the heart, arteries and veins. Cardiologists are certified by theAmerican Board of Internal Medicine (ABIM) after meeting educational and practice requirements. Before being certified as cardiologists, those aspiring to the specialty must be certified in internal medicine.
Then cardiologists can become certified in one of several cardiology subspecialties, including transplant cardiology, cardiovascular disease, clinical cardiac electrophysiology and interventional cardiology.
Lymphatic System: Facts, Functions & Diseases
The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials. The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body.
The lymphatic system primarily consists of lymphatic vessels, which are similar to the circulatory system’s veins and capillaries. The vessels are connected to lymph nodes, where the lymph is filtered. The tonsils, adenoids, spleen and thymus are all part of the lymphatic system.
Description of the lymphatic system
There are hundreds of lymph nodes in the human body. They are located deep inside the body, such as around the lungs and heart, or closer to the surface, such as under the arm or groin, according to the American Cancer Society.
The spleen, which is located on the left side of the body just above the kidney, is the largest lymphatic organ, according to the U.S. National Library of Medicine (NLM). It controls the amount of red blood cells and blood storage in the body, and helps to fight infection. If the spleen detects potentially dangerous bacteria, viruses, or other microorganisms in the blood, it — along with the lymph nodes — creates white blood cells called lymphocytes, which act as defenders against invaders. The lymphocytes produce antibodies to kill the foreign microorganisms and stop infections from spreading. Humans can live without a spleen, although people who have lost their spleen to disease or injury are more prone to infections.
Credit: by Ross Toro, Infographics Artist
The thymus is located in the chest just above the heart, according to Merck Manual. This small organ stores immature lymphocytes (specialized white blood cells) and prepares them to become active T cells, which help destroy infected or cancerous cells.
Tonsils are large clusters of lymphatic cells found in the pharynx. According to the American Academy of Otolaryngology, they are the body’s “first line of defense as part of the immune system. They sample bacteria and viruses that enter the body through the mouth or nose.” They sometimes become infected, and although tonsillectomies occur much less frequently today then they did in the 1950s, it is still among the most common operations performed and typically follows frequent throat infections.
Lymph is a clear and colorless fluid; the word “lymph” comes from the Latin word lympha, which means “connected to water,” according to the National Lymphadema Network.
Plasma leaves the body’s cells once it has delivered its nutrients and removed debris. Most of this fluid returns to the venous circulation through tiny blood vessels called venules and continues as venous blood. The remainder becomes lymph, according to the Mayo Clinic.
Unlike blood, which flows throughout the body in a continue loop, lymph flows in only one direction — upward toward the neck. Lymphatic vessels connect to two subclavian veins, which are located on either sides of the neck near the collarbones, and the fluid re-enters the circulatory system, according to the Mayo Clinic.
Diseases and disorders of the lymphatic system
Diseases and disorders of the lymphatic system are typically treated by immunologists. Vascular surgeons, dermatologists, oncologists and physiatrists also get involved in treatment of various lymphatic ailments. There are also lymphedema therapists who specialize in the manual drainage of the lymphatic system.
The most common diseases of the lymphatic system are enlargement of the lymph nodes (also known as lymphadenopathy), swelling due to lymph node blockage (also known as lymphedema) and cancers involving the lymphatic system, according to Dr. James Hamrick, chief of medical oncology and hematology at Kaiser Permanente in Atlanta.
When bacteria are recognized in the lymph fluid, the lymph nodes make more infection-fighting white blood cells, which can cause swelling. The swollen nodes can sometimes be felt in the neck, underarms and groin, according to the NLM.
Lymphadenopathy is usually caused by infection, inflammation, or cancer. Infections that cause lymphadenopathy include bacterial infections such as strep throat, locally infected skin wounds, or viral infections such as mononucleosis or HIV infection, Hamrick stated. “The enlargement of the lymph nodes may be localized to the area of infection, as in strep throat, or more generalized as in HIV infection. In some areas of the body the enlarged lymph nodes are palpable, while others are to deep to feel and can be seen on CT scan or MRI.”
Inflammatory or autoimmune conditions occur when a person’s immune system is active, and can result in enlargement of lymph nodes. This can happen in lupus, according to Hamrick.
Lymphoma is cancer of the lymph nodes. It occurs when lymphocytes grow and multiply uncontrollably. There are a number of different types of lymphoma, according to Dr. Jeffrey P. Sharman, director of research at Willamette Valley Cancer Institute and medical director of hematology research for the U.S. Oncology Network.
“The first ‘branch point’ is the difference between Hodgkin lymphoma and non-Hodgkin lymphoma (NHL),” Sharman said. Non-Hodgkin lymphoma is more common of the two, according to the Lymphoma Research Foundation.
The most common types of NHL are follicular, which accounts for about 30 percent of all NHL cases; diffuse large B-cell lymphoma (DLBCL), which comprises 40 to 50 percent of NHL cases; and Burkitt’s lymphoma, which accounts for 5 percent of NHL cases. “The remainder of cases makes up the bewildering complexity of NHL,” Sharman said.
“Though there can be a significant range within an individual category, the clinical approach to each category is unique and the expectations of patient outcome varies by category,” Sharman said.
When a person has had surgery and/or radiation to remove a cancer, the lymphatic flow back to the heart and can result in swelling or lymphedema, Hamrick noted. This most commonly occurs in women who have had surgery to remove a breast cancer. Part of the operation to remove the breast cancer involves removing lymph nodes in the armpit.
The more lymph nodes removed the higher the risk of chronic bothersome swelling and pain due to lymphedema in the arm, Hamrick explained. “Fortunately modern surgical techniques are allowing for fewer lymph nodes to be removed, and thus fewer cases of severe lymphedema for breast cancer survivors.”
Castleman disease is a group of inflammatory disorders that cause lymph node enlargement and can result in multiple-organ dysfunction, according to the Castleman Disease Cooperative Network. While not specifically a cancer, it is a similar to a lymphoma and is often treated with chemotherapy. It can be unicentric (one lymph node) or multicentric, involving multiple lymph nodes.
Lymphangiomatosis is a disease involving multiple cysts or lesions formed from lymphatic vessels, according to the Lymphangiomatosis & Gorham’s Disease Alliance. It is thought to be the result of a genetic mutation.
Diagnosis and treatment
Diseases of the lymphatic system are usually diagnosed when lymph nodes are enlarged, Hamrick noted. This may be discovered when the lymph nodes become enlarged enough to be felt (“palpable lymphadenopathy”) or are seen on imaging studies such as CT scans or MRIs.
The majority of enlarged lymph nodes are not dangerous; they are the body’s way of fighting off an infection, such as a viral upper respiratory infection. If the lymph nodes become significantly enlarged and persist longer than the infection then they are more worrisome. There is no specific size cutoff, but typically nodes that persist at larger than a centimeter are more worrisome and warrant examination by a doctor.
Common symptoms of any lymphatic disorder include swelling of the arm or groin, weight loss, fever and night sweats, according to Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York. “A PET or CAT scan is usually ordered to further investigate.”
The diagnosis of lymphadenopathy depends on the location of the abnormal lymph nodes and other things that are going on with the patient. If the patient has a known infection, then the lymph nodes can simply be followed to await resolution with treatment of the infection. If the nodes are growing quickly and there is no obvious explanation then typically a biopsy is warranted to look for a cancer or an infection. If the node can be felt then this can be done at the bedside with a needle, according to Hamrick.
If the lymph node is deeper, such as in the abdomen or pelvis, Hamrick said the biopsy might need to be done by an interventional radiologist using image guidance to place the needle into the node. Sometimes the biopsy needs to be done by a surgeon in the operating room. This is often where the most tissue can be obtained to make a diagnosis, he said.
With many types of lymphoma and leukemia, there are unique treatment options for each type, according to Sharman. “There is no one ‘summary’ of treatment options. Treatment options can include traditional chemotherapy, immunotherapy (such as using antibodies or immune modulating drugs), and even radiation.”
Treatment of lymphatic diseases depends on treating the underlying cause. Infections are treated with antibiotics, supportive care (while the immune system does its job, as in a viral infection) or antivirals. Lymphedema can be treated by elevation, compression and physical therapy. Cancers of the lymphatic system are treated by chemotherapy, radiotherapy, surgery, or a combination of those modalities, Hamrick noted.
In last several years, Sharman noted that there has been explosion of new treatment options. “There are a handful of newly approved drugs that target the actual disease causing processes within cells. Ibrutinib, idelalisib, obinutuzumab, lenalidomide have been approved in various indications and it is likely that we will see multiple more in coming year.”
Man Gets 20-Foot Tapeworm from Eating Raw Meat
Credit: The New England Journal of Medicine ©2016
A man in China who enjoyed eating raw beef became infected with a parasite — a 20-foot-long tapeworm —that came from including this food in his diet, a new case report reveals.
The parasite had attached to the 38-year-old man’s small intestine and had likely been inside him for at least two years before doctors diagnosed the infection as beef tapeworm of the species Taenia saginata, according to the case report, published online today (Jan. 20) in The New England Journal of Medicine.
Tapeworm infections are quite rare in Central China, where this case took place, said Jian Li, of the department of infectious diseases at Renmin Hospital in Shiyan, China, who diagnosed the man and co-authored the case report.
Although the tapeworm infection rate is quite high in the northwest and southwest districts of China, this was the first case of tapeworm seen in this part of China in 30 years, Li said.
Tapeworms are common globally, and Ethiopia, a country where people like to eat raw meat, has one of the highest rates of infection from beef tapeworm, said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, Texas, who was not involved in the case.
But beef tapeworms are rare in the United States, Hotez said.
According to the case report, the man went to see his doctor in the spring of 2015 because he was having stomach pain, vomiting, had lost his appetite, felt weak and was losing weight, Li told Live Science. The symptoms had begun just three days earlier, but the man had already lost about 5 to 10 kilograms (11 to 22 lbs.), he said. [The 10 Most Diabolical and Disgusting Parasites]
When the man came to the doctor’s office, he brought a fragment of the parasite with him that he found in his stool, Li said. He also told his doctor that he liked to eat raw beef.
From these two pieces of information — the parasite fragment in his stool, which was later examined under a microscope, and his consumption of raw beef — the doctors deduced that the man was infected with a beef tapeworm, Li said.
Over the past two years, the man’s medical history also showed that he had been seen by several different doctors and given treatment for stomachaches, pain in his abdomen and anemia, which is a low level of healthy red blood cells.
Credit: The New England Journal of Medicine ©2016
Tapeworms can live for years in a person’s intestines and cause no symptoms, or only mild ones, such as fullness or nausea after eating, Hotez told Live Science.
But it takes a long time for tapeworms to grow as long as this one did, Hotez explained, adding that other types of invertebrates, an animal group that includes worms, flies, snails and mosquitoes, tend to not live as long as tapeworms do.
No more rare beef
Cattle can become infected with T. saginatawhen they are out to pasture and feed on the eggs of the parasite, which were passed in human feces, especially in areas of poor sanitation, according to the Centers for Disease Control and Prevention (CDC). Those tapeworm eggs can hatch inside the cow, penetrate the intestinal wall and then circulate to the animal’s muscles.
People can become infected with the parasite by eating raw or undercooked beef from a contaminated cow. The tapeworm eggs and larvae can migrate to the small intestine, attach to the intestinal wall and mature into an adult tapeworm, the CDC says.
An adult tapeworm can produce eggs and tapeworm segments that are shed from the body in feces, according to the CDC.
Tapeworms from a related species, known as Taenia solium, can be acquired from eating raw or undercooked pork. But beef tapeworms tend to grow larger in size (up to 33 feet) and produce more eggs than pork tapeworms, according to the CDC.
If the larvae of a pork tapeworm have migrated out of the intestines and formed cysts in other tissues, such as the brain, they may cause neurological symptoms, including seizures. Pork tapeworms are a major cause of hundreds of thousands of cases of epilepsy worldwide, Hotez said. [Top 7 Germs in Food That Make You Sick]
Credit: The New England Journal of Medicine ©2016
Both beef and pork tapeworm are considered “neglected tropical diseases,” a category of infectious diseases that have never gotten much attention until recently, Hotez said.
In the case report, the man’s doctors explain that they treated their patient with an oral prescription medication that caused him to pass the long tapeworm out of his body 2.5 hours later.
Three months after expelling the tapeworm, the man felt better. His appetite and weight returned to normal.
But he likely will never eat raw or rare beef again, Li suspects. Being infected with a parasite for at least two years was a very unforgettable experience for the man, he explained.
“It was physically, emotionally and financially exhausting for him,” Li said.
This satellite image shows the outline of where Bolvia’s Lake Poopó used to be. Once the county’s second largest body of fresh water, it’s now dried up because of recurring drought and water diversion projects.
Typically, rainfall during the wet season (which runs from December to March) replenishes the lake. But we’re now well into January and rain remains scarce.
The image above was taken on April 12, 2013, and shows Lake Poopó when it’s filled with water. The one below was taken just six days ago on January 15, 2016. The water is essentially gone, replaced with dusty sand flats. The effect on the environment and ecosystem has been devastating.
This happened before in 1994, and it took several years for the water to return. But this time, scientists say recovery may not be possible. The APreports:
“This is a picture of the future of climate change,” says Dirk Hoffman, a German glaciologist who studies how rising temperatures from the burning of fossil fuels has accelerated glacial melting in Bolivia.
As Andean glaciers disappear so do the sources of Poopo’s water. But other factors are in play in the demise of Bolivia’s second-largest body of water behind Lake Titicaca.
Drought caused by the recurrent El Nino meteorological phenomenon is considered the main driver. Authorities say another factor is the diversion of water from Poopo’s tributaries, mostly for mining but also for agriculture.
A study by the German consortium Gitec-Cobodes determined that Poopo received 161 billion fewer liters of water in 2013 than required to maintain equilibrium.
“Irreversible changes in ecosystems could occur, causing massive emigration and greater conflicts,” said the study commissioned by Bolivia’s government.
Top image: Jesse Allen, using Landsat data from the U.S. Geological Survey.
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January 15, 2016
Mysterious shadow figure walking on clouds captured by plane passenger
Despite the figure was a bit away in the distance, I was able to watch the shadow figure for about two minutes and took some images of the strange phenomenon before then the aircraft slowly passed it.
To me, the shadow figure looks like a robot-like man or Michelin man but honestly I have no idea what it was, maybe it was just a rare cloud formation, said Nick.
Did Nick captured a rare natural sky phenomenon at 30,000ft or he witnessed something extraordinary, something from another world, that goes beyond the human capacity to understand what it could be?
Note: In the last enlarged and enhanced image of the shadow man, a human face is clearly visible.