Are Pop Rocks Dangerous?
Statistics Rule out Natural-warming Hypothesis
An analysis of temperature data since 1500 all but rules out the possibility that global warming in the industrial era is just a natural fluctuation in the earth’s climate, according to a new study by McGill Univ. physics professor Shaun Lovejoy.
The study, published in Climate Dynamics, represents a new approach to the question of whether global warming in the industrial era has been caused largely by man-made emissions from the burning of fossil fuels. Rather than using complex computer models to estimate the effects of greenhouse-gas emissions, Lovejoy examines historical data to assess the competing hypothesis: that warming over the past century is due to natural long-term variations in temperature.
Read more: http://www.laboratoryequipment.com/news/2014/04/statistics-rule-out-natural-warming-hypothesis
In a study published today in Nature Neuroscience, a group of researchers led by Takaomi Saido of the RIKEN Brain Science Institute in Japan have reported the creation of two new mouse models of Alzheimer’s disease that may potentially revolutionize research into this disease.
Alzheimer’s disease, the primary cause of dementia in the elderly, imposes a tremendous social and economic burden on modern society. In Japan, the burden of the disease in 2050 is estimated to be a half a trillion US dollars, a figure equivalent to the government’s annual revenues.
Unfortunately, it has proven very difficult to develop drugs capable of ameliorating the disease. After a tremendous burst of progress in the 1990s, the pace of discoveries has slowed. Dr. Saido believes that part of the difficulty is the inadequacy of current mouse models to replicate the real conditions of Alzheimer’s disease and allow an understanding of the underlying mechanisms that lead to neurodegeneration. In fact, much of the research in Alzheimer’s disease over the past decade may be flawed, as it was based on unrealistic models.
The problem with older mouse models is that they overexpress a protein called amyloid precursor protein, or APP, which gives rise to the amyloid-beta (Abeta) peptides that accumulate in the brain, eventually leading to the neurodegeneration that characterizes Alzheimer’s disease. However, in mice the overexpression of APP gives rise to effects which are not seen in human Alzheimer’s disease.
For example, the APP mutant mice often die of unknown causes at a young age, and the group believes this may be related to the generation of toxic fragments of APP, such as CTF-beta. In addition, some of the fragments of APP could be neuroprotective, making it difficult to judge whether drugs are being effective due to their effect on Abeta peptides, which are known to be involved in human AD, or whether it is due to other effects that would not be seen in human disease. In addition, the gene for expressing APP is inserted in different places in the genome, and may knock out other genes, creating artifacts that are not seen in humans.
With this awareness, more than a decade ago Dr. Saido launched a project to develop a new mouse model that would allow more accurate evaluation of therapies for the disease. One of the major hurdles involved a part of the gene, intron 16, which they discovered was necessary for creating more specific models.
The first mice model they developed (NL-F/NL-F) was knocked in with two mutations found in human familial Alzheimer’s disease. The mice showed early accumulation of Abeta peptides, and importantly, were found to undergo cognitive dysfunction similar to the progression of AD seen in human patients. A second model, with the addition of a further mutation that had been discovered in a family in Sweden, showed even faster initiation of memory loss.
These new models could help in two major areas. The first model, which expresses high levels of the Abeta peptides, seems to realistically model the human form of AD, and could be used for elucidating the mechanism of Abeta deposition. The second model, which demonstrates AD pathology very early on, could be used to examine factors downstream of Abeta-40 and Abeta-42 deposition, such as tauopathy, which are believed to be involved in the neurodegeneration. These results may eventually contribute to drug development and to the discovery of new biomarkers for Alzheimer’s disease. The group is currently looking at several proteins, using the new models, which have potential to be biomarkers.
According to Dr. Saido, “We have a social responsibility to make Alzheimer’s disease preventable and curable. The generation of appropriate mouse models will be a major breakthrough for understanding the mechanism of the disease, which will lead to the establishment of presymptomatic diagnosis, prevention and treatment of the disease.”
At TEDxYouth@Manchester, genetics researcher Dan Davis introduces the audience to compatibility genes — key players in our immune system’s functioning, and the reason why it’s so difficult to transplant organs from person to person: one’s compatibility genes must match another’s for a transplant to take.
(Images from Davis’s talk, Drew Berry’s animations, and the TED-Ed lessons A needle in countless haystacks: Finding habitable worlds - Ariel Anbar and How we conquered the deadly smallpox virus - Simona Zompi)
photos by marine biologist thomas peschak (previously featured) of whale sharks in the gulf of tadjoura, djibouti, where they feed at night on zooplankton that are attracted to the lights of small fishing boats. this is the only place where whale sharks have been documented feeding at night.
whale sharks are docile, slow moving filter feeders that feed by drifting with their capacious mouths open, drawing in plankton, fish, and small crustaceans. but foreign objects, such as plastic, can also be drawn into the shark’s digestive system, causing them harm.
whale sharks, the largest non mammalian vertebrates on the planet, originated some sixty million years ago, but are now listed as a vulnerable species, coming under particular threat from boat propellers and pollution. they are also hunted for their fins, though the u.a.e. banned the shark fin trade in 2008.
Better put a ring on it. Abell 33. Created when an aging star blew off its outer layers, this beautiful blue bubble is aligned with a foreground star and bears an uncanny resemblance to a diamond engagement ring. This cosmic gem is unusually symmetric, appearing to be almost circular.
"Umbrella Crab" (Cryptolithodes sitchensis)
Also known as the Sitka crab or the Turtle Crab, the umbrella crab is a species of lithodid crab that is native to coastal regions of the northeastern Pacific, ranging from Sitka, Alaska to Point Loma, California. C. sitchensis is noted for having a unusual half-moon shaped carapace that extends over its walking legs and chelipeds, this serves as a form of camouflage allowing C. sitchensis to blend in with the rocks around it. The color of C. sitchensis’s carapace is highly variable and often matches the color of the coralline algae with C. sitchensis feeds on.
Neuroscientists identify a brain circuit that’s key to shifting our focus from one object to another.
Picking out a face in the crowd is a complicated task: Your brain has to retrieve the memory of the face you’re seeking, then hold it in place while scanning the crowd, paying special attention to finding a match.
A new study by MIT neuroscientists reveals how the brain achieves this type of focused attention on faces or other objects: A part of the prefrontal cortex known as the inferior frontal junction (IFJ) controls visual processing areas that are tuned to recognize a specific category of objects, the researchers report in the April 10 online edition of Science.
Scientists know much less about this type of attention, known as object-based attention, than spatial attention, which involves focusing on what’s happening in a particular location. However, the new findings suggest that these two types of attention have similar mechanisms involving related brain regions, says Robert Desimone, the Doris and Don Berkey Professor of Neuroscience, director of MIT’s McGovern Institute for Brain Research, and senior author of the paper.
“The interactions are surprisingly similar to those seen in spatial attention,” Desimone says. “It seems like it’s a parallel process involving different areas.”
In both cases, the prefrontal cortex — the control center for most cognitive functions — appears to take charge of the brain’s attention and control relevant parts of the visual cortex, which receives sensory input. For spatial attention, that involves regions of the visual cortex that map to a particular area within the visual field.
In the new study, the researchers found that IFJ coordinates with a brain region that processes faces, known as the fusiform face area (FFA), and a region that interprets information about places, known as the parahippocampal place area (PPA). The FFA and PPA were first identified in the human cortex by Nancy Kanwisher, the Walter A. Rosenblith Professor of Cognitive Neuroscience at MIT.
The IFJ has previously been implicated in a cognitive ability known as working memory, which is what allows us to gather and coordinate information while performing a task — such as remembering and dialing a phone number, or doing a math problem.
For this study, the researchers used magnetoencephalography (MEG) to scan human subjects as they viewed a series of overlapping images of faces and houses. Unlike functional magnetic resonance imaging (fMRI), which is commonly used to measure brain activity, MEG can reveal the precise timing of neural activity, down to the millisecond. The researchers presented the overlapping streams at two different rhythms — two images per second and 1.5 images per second — allowing them to identify brain regions responding to those stimuli.
“We wanted to frequency-tag each stimulus with different rhythms. When you look at all of the brain activity, you can tell apart signals that are engaged in processing each stimulus,” says Daniel Baldauf, a postdoc at the McGovern Institute and the lead author of the paper.
Each subject was told to pay attention to either faces or houses; because the houses and faces were in the same spot, the brain could not use spatial information to distinguish them. When the subjects were told to look for faces, activity in the FFA and the IFJ became synchronized, suggesting that they were communicating with each other. When the subjects paid attention to houses, the IFJ synchronized instead with the PPA.
The researchers also found that the communication was initiated by the IFJ and the activity was staggered by 20 milliseconds — about the amount of time it would take for neurons to electrically convey information from the IFJ to either the FFA or PPA. The researchers believe that the IFJ holds onto the idea of the object that the brain is looking for and directs the correct part of the brain to look for it.
The MEG scanner, as well as the study’s “elegant design,” were critical to discovering this relationship, says Robert Knight, a professor of psychology and neuroscience at the University of California at Berkeley who was not part of the research team.
“Functional MRI gives hints of connectivity,” Knight says, “but the time course is way too slow to show these millisecond-scale frequencies and to establish what they show, which is that the inferior frontal lobe is the prime driver.”
Further bolstering this idea, the researchers used an MRI-based method to measure the white matter that connects different brain regions and found that the IFJ is highly connected with both the FFA and PPA.
Members of Desimone’s lab are now studying how the brain shifts its focus between different types of sensory input, such as vision and hearing. They are also investigating whether it might be possible to train people to better focus their attention by controlling the brain interactions involved in this process.
“You have to identify the basic neural mechanisms and do basic research studies, which sometimes generate ideas for things that could be of practical benefit,” Desimone says. “It’s too early to say whether this training is even going to work at all, but it’s something that we’re actively pursuing.”
Anti-vax claim: Because most dangerous diseases have been virtually eliminated in wealthy countries like the United States, vaccinations have basically become unnecessary.
Debunk: It only takes a few cases for an outbreak to resurface in a population with low vaccination coverage. In fact, due to anti-vaccine paranoia, there’s been several measles (red) and whooping cough (green) outbreaks in the US recently.
Importantly, getting vaccinated protects those around us. A small number of the population are unable to be vaccinated (small children, the elderly), so their protective barrier is vaccinated people around them who stop the spread of the disease. This concept is known as “herd immunity.”