The American Civil War was fought over whether people could own other people. Any argument otherwise is ignoring the basic fact that the states were fighting for their right…to own slaves.
18 maio 2015
Auroras and Star Trails over Iceland
It was one of the quietest nights of aurora in weeks. Even so, in northern- Iceland during last November, faint auroras lit up the sky every clear night. The featured 360-degree panorama is the digital fusion of four wide-angle cameras each simultaneously taking 101 shots over 42 minutes. In the foreground is serene Lake Myvatn dotted with picturesque rock formations left over from ancient lava flows. Low green auroras sweep across the sky above showing impressive complexity near the horizon. Stars far in the distance appear to show unusual trails -- as the Earth turned -- because early exposures were artificially faded.
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First human embryos genetically modified – more will come The...
First human embryos genetically modified – more will come
The prospect of genetically engineering humans has come a step closer, with the publication of the first paper to describe efforts to modify embryos. There is a long way to go before we can safely tinker with our genes, but at least one group in the US and four in China are aiming to edit human embryos: this will be the first of many studies.
The work was done using a gene editing technique called CRISPR (pronounced “crisper”).
The idea of gene editing is to make specific changes in a particular gene, just as you might correct a spelling mistake. Gene editing has been around for decades, but in organisms other than mice it used to be difficult, expensive and time-consuming.
The CRISPR method – the name refers to characteristic sets of repeating chunks of DNA known as “clustered regularly interspaced short palindromic repeats” – developed in just the past few years, has changed all that, allowing biologists to achieve in weeks what used to take years.
The ease, speed and cheapness of CRISPR has made it possible for more people to experiment with gene editing. Last month, it was reported that a handful of teams are trying to modify human embryos using the method. Now one of those teams, led by Junjiu Huang at the Sun Yat-sen University in Guangzhou, China, has published its results.
Rejected eggs
“Because ethical concerns preclude studies of gene editing in normal embryos,” the team writes, the researchers used human eggs that had been fertilised by two sperm rather than one.
These “polyspermic” eggs may develop for a few days but never develop normally and are discarded by fertility clinics.
Huang’s team then attempted to modify one of the genes coding for the oxygen-carrying blood protein haemoglobin. Mutations in this gene cause the disease beta-thalassemia, itself a target for previous gene-editing attempts. The team injected the various snippets of RNA and DNA needed for CRISPR into the polyspermic eggs. One of the DNA sequences was a “template” for the desired changes to the gene, intended to guide the repair process.
Of the 86 eggs injected, just four were successfully modified – an efficiency rate far lower than required to make human germline gene editing a practical prospect. The others either did not survive, or were not successfully modified.
Missing the target
There were also changes to genes other than the globin gene. Such “off-target” alterations are a big concern, because they could cause serious illnesses.
It should be possible to reduce the number of off-target changes by refining the CRISPR method. However, it will probably never be possible to completely eliminate them. So if gene editing were ever to be used for modifying inherited human genetic material, it would be essential to check embryos for any off-target effects before implanting them in the mother-to-be.
In theory, this can be done by removing a single cell from a developing embryo and sequencing its DNA – a method already sometimes used during IVF to ensure embryos don’t carry serious disease mutations, called preimplantation genetic diagnosis.
Living mosaics
However, Huang and his colleagues found what could be a serious problem: the embryos were a mixture of modified and unmodified cells – so-called genetic mosaics. That means the results of preimplantation genetic testing could be misleading.
On the face of it, these findings are not encouraging for those hoping to use gene editing to correct hereditary diseases in children. However it is too soon to draw sweeping conclusions. The low efficiency and the mosaicism could be a result of using flawed eggs. There might also be a specific problem with their approach – the paper was published just a day after being received by the journal, so it has not yet been thoroughly scrutinised by independent researchers. What’s more, CRISPR is still a new method, so it is likely to be improved greatly in the coming years.
But should this kind of research be done at all? That depends on whether you think modifying the inheritable DNA of the human germline is acceptable. Some have called for a moratorium on this kind of work, and according to Huang, the paper was rejected by the journals Science and Nature in part because of ethical concerns.
Polls in various countries, however, indicate that there is actually substantial public support – sometimes over 50 per cent – for using germline modification to prevent genetic diseases.
The efficiency of gene editing can vary greatly across both species and cell types. So to find out whether any method is safe and effective it is necessary to try it in human embryos.
Journal reference: Protein Cell, DOI: 10.1007/s13238-015-0153-5
clouds over california, photographed by goes 15, 15h may...
clouds over california, photographed by goes 15, 15h may 2015.
the pacific ocean is at bottom left. nevada covers top right.
top: 14 images, photographed 10:00-16:30 pdt.
middle: difference between sequential images.
bottom: difference between each frame and the first in the sequence.
image credit: noaa/nasa. animation etc.: ageofdestruction
ageDevice may allow sensations in prosthetic hands To the...
Device may allow sensations in prosthetic hands
To the nearly 2 million people in the United States living with the loss of a limb, including U.S. military veterans, prosthetic devices provide restored mobility, yet lack sensory feedback. A team of engineers and researchers at Washington University in St. Louis is working to change that so those with upper limb prosthetics can feel hot and cold and the sense of touch through their prosthetic hands.
Daniel Moran, PhD, professor of biomedical engineering in the School of Engineering & Applied Science and of neurobiology, of physical therapy and of neurological surgery at Washington University School of Medicine in St. Louis, has received a three-year, nearly $1.9 million grant from the Defense Advanced Research Projects Agency (DARPA) to test a novel device developed in his lab that would stimulate the nerves in the upper arm and forearm. If it works, upper-limb amputees who use motorized prosthetic devices would be able to feel various sensations through the prosthetic, which would send sensory signals to the brain.
DARPA is already funding the “Luke Arm,” a high-tech bionic limb created by DEKA Research. The prosthetic is named for “Star Wars” character Luke Skywalker, who received a prosthetic after losing his right hand in an epic battle with Darth Vader. It is designed to help servicemen and women and veterans who had upper limb amputations. While the advanced prosthetic arm allows users to perform six different grips, such as picking up small objects, it does not provide users with the sense of touch and orientation of a natural hand.
Moran, whose expertise is in motor neurophysiology and brain-computer interfaces, and his team have developed an electrode designed to stimulate sensory nerve cells in the ulnar and median nerves in the arms. The ulnar nerve, one of three main nerves in the forearm, is the largest nerve in the body unprotected by muscle or bone and is connected to the ring finger and pinkie finger on the hand. It’s the nerve that is stimulated when a hit to the elbow triggers the “funny bone.” The median nerve in the upper arm and shoulder is connected to the other fingers on the hand, so together, the two nerves control movement and sensations including touch, pressure, vibration, heat, cold and pain in all of the fingers.
People using arm prosthetics have to rely on their vision to use them properly, Moran said. To pick up a cup of coffee, they have to be able to see the cup, place the fingers of the prosthesis around it and lift it. They are unable to feel whether the cup is in their hand, if the cup is hot or cold, or if they are about to drop it. By enabling the ability to feel, users will have more control over the prosthesis.
Moran’s team includes Harold Burton, PhD, professor of neurobiology and Wilson (Zach) Ray, MD, assistant professor of neurological surgery, both at the School of Medicine; and Matthew MacEwen, who graduates this month with an MD/PhD and who worked on this project for his dissertation. The team developed a macro-sieve peripheral nerve interface designed to stimulate regeneration of the ulnar and median nerves to transmit information back into the central nervous system.
Ray will implant the device — which is made of an ultrathin, flexible material similar to a soft contact lens and is about one-eighth the size of a dime — into the forearms of anesthetized nonhuman primates. The research team will then determine the amount of sensory information that is encoded by providing low levels of stimulation to small groups of nerves. The device, which looks like a wagon wheel with open spaces between the “spokes,” allows the nerve to grow. Ray also will implant a small cuff electrode, the current standard of care, to compare the performance.
Once implanted, Moran and the team will train the nonhuman primates to play a joystick-controlled videogame, in which the team will give them cues as to where to move the joystick by stimulating specific sectors in the ulnar and median nerves so it feels as if someone is touching them, Moran said. Their reward for advancing through the various stages of the game successfully is fruit-flavored juice.
“We want to determine what they can perceive through artificial stimulation of the nerves,” Moran said. “If we stimulate a particular sector of the nerve, that tells them to reach to a specific target. Using very low levels of stimulation (i.e. sensation), we want to figure out how many different nerve sectors we can independently encode with a unique target location.”
In particular, Moran and the team will analyze how many different independent channels they can stimulate on the nerve to determine how many sensors will work on the prosthetic hand. Using a method called current steering, they can move different amounts of current around the nerve to activate different sectors to connect the touch sensors on the hand to a different sector on the nerve. His team has already had success with this method in motor neurons in a rat model.
“If this works to stimulate motor neurons in muscles, we can certainly stimulate sensory neurons, and that’s never been done in a behavioral model in nonhuman primates,” Moran said.
Burton, an expert in sensory neurophysiology, will analyze how the brain processes the feedback from the nerve stimulation.
“The more real estate the brain uses, the more processing power and the more important something is,” Moran said. “The hand area in the somatosensory cortex is a big piece of brain, so there should be a lot of bandwidth. We think we’ll be able to send a lot of information to it.”
Moran and his team will work with DARPA to determine how many sensors to put on the prosthetic hands.
“If the nervous system can’t handle more than eight or 10 channels, there is no sense in putting more on there,” he said. “We want to find the bandwidth and what the nervous system can interpret with artificial sensation.”
Image1&2: Daniel Moran, PhD, and his team have developed a novel device that would stimulate the nerves in the upper arm and forearm, possibly giving amputees with prosthetics the ability to feel.
Image3: The device is about one-eighth the size of a dime and made of an ultrathin, flexible material similar to a soft contact lens.
In the mid-1600s, Harvard created the Indian College to “educate” and convert Native...
In the mid-1600s, Harvard created the Indian College to “educate” and convert Native Americans. It was disassembled in 1693.
GO HERE –> http://bit.ly/MustWatchPsychFilm To help...
GO HERE –> http://bit.ly/MustWatchPsychFilm To help make sure this excellent film gets finished. Please like and share!
todaysdocument: Mount St. Helens Erupts, 8:32 A.M., May 18,...
Volcanoes - Before Mount St. Helens Eruption - Washington National Archives Identifier: 7035223
Volcanoes - Before Mount St. Helens Eruption - Washington National Archives Identifier: 7035218
Volcanoes - After Mount St. Helens Eruption - Washington National Archives Identifier: 7035237
Mount St. Helens Erupts, 8:32 A.M., May 18, 1980
After several months of grumbling, Mount St. Helens in southeast Washington state roared to life 35 years ago on May 18, 1980 at 8:32 A.M. For nine hours the volcano erupted, destroying plant and animal life in the surrounding 230 square miles of forest. The blast of ash, rock, and steam blew across the land at speeds up to 670 miles per hour, with the ash plume reaching 15 miles upwards. It ranks as the most destructive volcanic event in the United States, leaving 57 dead, devastating hundreds of square miles, and causing over a billion dollars in damages.
- Volcanoes - Before Mount St. Helens Eruption - Washington
- Volcanoes - Before Mount St. Helens Eruption - Washington
- Volcanoes - After Mount St. Helens Eruption - Washington
From the series: Photographs Relating to National Forests, Resource Management Practices, Personnel, and Cultural and Economic History, ca. 1897 - ca. 1980
These photos are from a series over 60,000 photos relating to the National Forests. We need your help transcribing the typed captions on these images. This easy transcription mission will help make these vintage images more accessible and searchable in the usnatarchives online catalog:
Mount St. Helens at 35
vox: Some jobs are just obviously dangerous — construction...
vox:
Some jobs are just obviously dangerous — construction workers fall from high places, farmers deal with dangerous machinery, and fishers drown. But what are the biggest risks for all the other workers sitting behind desks or ringing up groceries or waiting tables?
The Bureau of Labor Statistics actually answers these questions in its Census of Fatal Occupational Injuries. We’ve used that data to create one big, simple, morbid chart that shows how American workers meet their ends on the job.
May 18th 1868: Tsar Nicholas II bornOn this day in 1868, the...
Tsar Nicholas II (1868 - 1918)
Coronation of Tsar Nicholas II
The Romanov family
May 18th 1868: Tsar Nicholas II born
On this day in 1868, the future Tsar of Russia, Nicholas Romanov, was born in Alexander Palace. He became Tsar in 1894 upon the death of his father Tsar Alexander III. Nicholas’s reign was mired by Russia’s poor performance in the Russo-Japanese and First World War, and the wars’ devastating impact on the Russian people. Opposition to the Tsar also rose due to his repression of dissenters and that he left the government in the hands of his wife Tsarina Alexandra and their adviser Rasputin. The unrest culminated in the February Revolution (it was February by the old Russian calendar, but March in the modern Gregorian Calendar), which forced the Tsar out of power. Nicholas, facing pressure from his people and his ministers, decided to abdicate the throne in favour of his brother, Grand Duke Michael. However, Michael refused to take the crown and therefore Nicholas became the last Tsar of Russia, and the reign of the Romanov family came to an end after over 300 years on the throne. A Provisional Government replaced the Tsar, however this too was overthrown in October 1917 and replaced with a Bolshevik dictatorship under Vladimir Lenin, thus beginning Communist rule in Russia which would last until 1991. Nicholas and his wife and children were brutally murdered by the Bolshevik secret police - the Cheka - in July 1918.
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