【每日阅读训练第四期——速度越障6系列】【6-2】科技

CHRISTINE2010

[attachimg=598,633]104664[/attachimg]原定周六晚上发“文史哲”类的泾渭不凡同学要光荣退休了~~ 有谁对接替饭饭的岗位感兴趣的请尽快联系“铁板神猴”~先到先得哦！谢谢大家！


【计时一】

Old Skull Bone Rediscovered in Mammals

ScienceDaily (Aug. 14, 2012) — Although clearly discernible in the embryo, shortly afterwards it fuses with other bones beyond recognition. Consequently, researchers have often missed it. Now, however, paleontologists from the University of Zurich have rediscovered it: the "os interparietale," a skull bone also referred to as the interparietal. Using imaging methods, they were able to detect its presence in all mammals -- including humans, which is new as it was previously believed to have been lost in the course of evolution.
[attachimg=533,463]104662[/attachimg]

The mammalian skull, including that of people, is composed of about 20 bones. Fish, reptile and bird skulls, however, have considerably more. After all, when mammals evolved from reptile-like vertebrates 320 million years ago, the skull's structure became simplified during its development and the number of skull bones decreased.
Some bones were lost in the lineage leading to mammals in the course of evolution, especially a number of skull roof bones. The skull's interparietal, which is one of the skull roof bones, particularly puzzled researchers: on the one hand, it seems to have survived, such as in humans, carnivores and ungulates (especially horses); on the other hand, it is not found in all mammals.
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【计时二】

Together with a colleague from the University of Tübingen, Marcelo Sánchez, a professor of paleontology at the University of Zurich, and post-doctoral student Daisuke Koyabu have now detected the presence of the interparietal after all: Studying fossils and embryos of over 300 species of vertebrate, they were able to identify the bone in all of them. They used non-invasive micro-CT imaging to analyze rare embryos of different species from museum collections. "The interparietal was clearly discernible in specimens from the embryonic period as the skull bones were fused less strongly here," explains Sánchez. At the same time, he sees the fact that the bone is only clearly and easily discernible in the embryonic period as the reason why previous researchers failed to recognize it: "It would seem that many anatomists have overlooked the presence of the interparietal in numerous mammalian lineages as the bone becomes fused to other skull bones during growth and is unrecognizable in adult individuals."
Same skull bone in fish and humans
Another result that also refutes previous assumptions concerns the origin of the bone. As Koyabu reports: "Whilst it was previously assumed that the mammalian interparietal was composed of two elements, we discovered that it develops from four elements: a medial and a lateral pair."
The tabular bones of our reptile-like ancestors and fish correspond to the lateral interparietal bones, which were overlooked until now. According to the new results, however, they have survived in mammalian lineages after all.
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The results also explain the mixed evolutionary tissue origin of the interparietal complex, which had been identified in mice but could not be confirmed by conventional anatomical tests: Genetic studies have revealed that the lateral bone pair develops from the mesoderm, but the medial pair from the neural crest cells.
This present study provides a conclusive explanation for the hitherto inexplicable mixed tissue origin of the interparietal complex: It stems from the evolutionary fusion of the os interparietale to the tabular bones in mammalian lineages.
The study also yields insights into us people, as Sánchez concludes: "The evidence of the continuation of fish bones in mammals provides new insights into the origins of our own anatomy." These anatomical discoveries were made possible thanks to a microtomographic imaging, the museum collections of rare animal embryos and the interdisciplinary collaboration between paleontology and embryology.
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【计时三】

How Computation Can Predict Group Conflict: Fighting Among Captive Pigtailed Macaques Provides Clues

ScienceDaily (Aug. 13, 2012) — When conflict breaks out in social groups, individuals make strategic decisions about how to behave based on their understanding of alliances and feuds in the group.
[attachimg=566,848]104663[/attachimg]

But it's been challenging to quantify the underlying trends that dictate how individuals make predictions, given they may only have seen a small number of fights or have limited memory.
In a new study, scientists at the Wisconsin Institute for Discovery (WID) at UW-Madison develop a computational approach to determine whether individuals behave predictably. With data from previous fights, the team looked at how much memory individuals in the group would need to make predictions themselves. The analysis proposes a novel estimate of "cognitive burden," or the minimal amount of information an organism needs to remember to make a prediction.
The research draws from a concept called "sparse coding," or the brain's tendency to use fewer visual details and a small number of neurons to stow an image or scene. Previous studies support the idea that neurons in the brain react to a few large details such as the lines, edges and orientations within images rather than many smaller details.
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【计时四】

"So what you get is a model where you have to remember fewer things but you still get very high predictive power -- that's what we're interested in," says Bryan Daniels, a WID researcher who led the study. "What is the trade-off? What's the minimum amount of 'stuff' an individual has to remember to make good inferences about future events?"
To find out, Daniels -- along with WID co-authors Jessica Flack and David Krakauer -- drew comparisons from how brains and computers encode information. The results contribute to ongoing discussions about conflict in biological systems and how cognitive organisms understand their environments.
The study, published in the Aug. 13 edition of the Proceedings of the National Academy of Sciences, examined observed bouts of natural fighting in a group of 84 captive pigtailed macaques at the Yerkes National Primate Research Center. By recording individuals' involvement -- or lack thereof -- in fights, the group created models that mapped the likelihood any number of individuals would engage in conflict in hypothetical situations.
To confirm the predictive power of the models, the group plugged in other data from the monkey group that was not used to create the models. Then, researchers compared these simulations with what actually happened in the group. One model looked at conflict as combinations of pairs, while another represented fights as sparse combinations of clusters, which proved to be a better tool for predicting fights. From there, by removing information until predictions became worse, Daniels and colleagues calculated the amount of information each individual needed to remember to make the most informed decision whether to fight or flee.
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【计时五】

"We know the monkeys are making predictions, but we don't know how good they are," says Daniels. "But given this data, we found that the most memory it would take to figure out the regularities is about 1,000 bits of information."
Sparse coding appears to be a strong candidate for explaining the mechanism at play in the monkey group, but the team points out that it is only one possible way to encode conflict.
Because the statistical modeling and computation frameworks can be applied to different natural datasets, the research has the potential to influence other fields of study, including behavioral science, cognition, computation, game theory and machine learning. Such models might also be useful in studying collective behaviors in other complex systems, ranging from neurons to bird flocks.
Future research will seek to find out how individuals' knowledge of alliances and feuds fine tunes their own decisions and changes the groups' collective pattern of conflict.
The research was supported by the National Science Foundation, the John Templeton Foundation through the Santa Fe Institute, and UW-Madison.
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【越障】

New System Could Predict Solar Flares, Give Advance Warning

ScienceDaily (Aug. 13, 2012) — Researchers may have discovered a new method to predict solar flares more than a day before they occur, providing advance warning to help protect satellites, power grids and astronauts from potentially dangerous radiation.



The system works by measuring differences in gamma radiation emitted when atoms in radioactive elements "decay," or lose energy. This rate of decay is widely believed to be constant, but recent findings challenge that long-accepted rule.
The new detection technique is based on a hypothesis that radioactive decay rates are influenced by solar activity, possibly streams of subatomic particles called solar neutrinos. This influence can wax and wane due to seasonal changes in Earth's distance from the sun and also during solar flares, according to the hypothesis, which is supported with data published in a dozen research papers since it was proposed in 2006, said Ephraim Fischbach, a Purdue University professor of physics.
Fischbach and Jere Jenkins, a nuclear engineer and director of radiation laboratories in the School of Nuclear Engineering, are leading research to study the phenomenon and possibly develop a new warning system. Jenkins, monitoring a detector in his lab in 2006, discovered that the decay rate of a radioactive sample changed slightly beginning 39 hours before a large solar flare.
Since then, researchers have been examining similar variation in decay rates before solar flares, as well as those resulting from Earth's orbit around the sun and changes in solar rotation and activity. The new findings appeared online last weekin the journal Astroparticle Physics.
"It's the first time the same isotope has been used in two different experiments at two different labs, and it showed basically the same effect," Fischbach said. The paper was authored by Jenkins and Fischbach; Ohio State University researchers Kevin R. Herminghuysen, Thomas E. Blue, Andrew C. Kauffman and Joseph W. Talnagi; U.S. Air Force researcher Daniel Javorsek; Mayo Clinic researcher Daniel W. Mundy; and Stanford University researcher Peter A. Sturrock.
Data were recorded during routine weekly calibration of an instrument used for radiological safety at Ohio State's research reactor. Findings showed a clear annual variation in the decay rate of a radioactive isotope called chlorine 36, with the highest rate in January and February and the lowest rate in July and August, over a period from July 2005 to June 2011.
The new observations support previous work by Jenkins and Fischbach to develop a method for predicting solar flares. Advance warning could allow satellite and power grid operators to take steps to minimize impact and astronauts to shield themselves from potentially lethal radiation emitted during solar storms.
The findings agree with data previously collected at the Brookhaven National Laboratory regarding the decay rate of chlorine 36; changes in the decay rate were found to match changes in the Earth-sun distance and Earth's exposure to different parts of the sun itself, Fischbach said.
Large solar flares may produce a "coronal mass ejection" of highly energetic particles, which can interact with Earth's magnetosphere, triggering geomagnetic storms that sometimes knock out power. The sun's activity is expected to peak over the next year or so as part of an 11-year cycle that could bring strong solar storms.
Solar storms can be especially devastating if the flare happens to be aimed at Earth, hitting the planet directly with powerful charged particles. A huge solar storm, called the Carrington event, hit Earth in 1859, a time when the only electrical infrastructure consisted of telegraph lines.
"There was so much energy from this solar storm that the telegraph wires were seen glowing and the aurora borealis appeared as far south as Cuba," Fischbach said. "Because we now have a sophisticated infrastructure of satellites, power grids and all sort of electronic systems, a storm of this magnitude today would be catastrophic. Having a day and a half warning could be really helpful in averting the worst damage."
Satellites, for example, might be designed so that they could be temporarily shut down and power grids might similarly be safeguarded before the storm arrived.
Researchers have recorded data during 10 solar flares since 2006, seeing the same pattern.
"We have repeatedly seen a precursor signal preceding a solar flare," Fischbach said. "We think this has predictive value."
The Purdue experimental setup consists of a radioactive source -- manganese 54 -- and a gamma-radiation detector. As the manganese 54 decays, it turns into chromium 54, emitting a gamma ray, which is recorded by the detector to measure the decay rate.
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Purdue has filed a U.S. patent application for the concept.
Research findings show evidence that the phenomenon is influenced by Earth's distance from the sun; for example, decay rates are different in January and July, when Earth is closest and farthest from the sun, respectively.
"When the Earth is farther away, we have fewer solar neutrinos and the decay rate is a little slower," Jenkins said. "When we are closer, there are more neutrinos, and the decay a little faster."
Researchers also have recorded both increases and decreases in decay rates during solar storms.
"What this is telling us is that the sun does influence radioactive decay," Fischbach said.
Neutrinos have the least mass of any known subatomic particle, yet it is plausible that they are somehow affecting the decay rate, he said.
English physicist Ernest Rutherford, known as the father of nuclear physics, in the 1930s conducted experiments indicating the radioactive decay rate is constant, meaning it cannot be altered by external influences.
"Since neutrinos have essentially no mass or charge, the idea that they could be interacting with anything is foreign to physics," Jenkins said. "So, we are saying something that doesn't interact with anything is changing something that can't be changed. Either neutrinos are affecting decay rate or perhaps an unknown particle is."
Jenkins discovered the effect by chance in 2006, when he was watching television coverage of astronauts spacewalking at the International Space Station. A solar flare had erupted and was thought to possibly pose a threat to the astronauts. He decided to check his equipment and discovered that a change in decay-rate had preceded the solar flare.
Further research is needed to confirm the findings and to expand the work using more sensitive equipment, he said.
Jenkins and Fischbach have previously collaborated with Peter Sturrock, a professor emeritus of applied physics at Stanford University and an expert on the inner workings of the sun, to examine data collected at Brookhaven on the decay rate of radioactive isotopes silicon-32 and chlorine-36. The team reported in 2010 in Astroparticle Physics that the decay rate for both isotopes varies in a 33-day recurring pattern, which they attribute to the rotation rate of the sun's core.
The group found evidence of the same annual and 33-day effect in radium-226 data taken at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, Germany, and those findings were published in 2011. They also found an additional 154-day recurring pattern in both the Brookhaven and PTB data, published in 2011, which they believe to be solar related and similar to a known solar effect called a Rieger periodicity.
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xjbb

沙发！谢谢lz～

Speed:
2'53
Component I related to skull is discovered in most of mammals. The article addresses the process of its evolution, in contrast to that of birds and fish, as well as why other scientists have been overlooking it.
1'55
2 pairs of xx were discovered in stead of one in mammals. something about mixed evolution. what can this discovery bring to research field.
1'24
If individual can predict conflicts among or between groups, maybe computation based on memories of past conflicts can discover it.
1'52
What's the minimal memory a effective prediction need? Scientists did 2 type of experiments for comparison.
1'02
What else fields can this model be used in, what is the significance of researches like this.

Obstacle:
10'02
Main idea:
Solar flare is supposed to be predicted by measuring the decay rate of radioactive substance.
1) why it's necessary for humankind to predict solar flare: it may cause satellites dysfunctional, the radiation does great harm to human body so the astronauts will be dangerous without any protection.
2) Based on what theory and technology can human predict solar flare: radioactive decay rate. According to some scientists, this rate is effected by solar activities.
3) According to some experiments and observations, radioactive decay rate starts to change hours before solar flare occurs - this makes prediction possible.
4) More examples of damages caused by solar flares in the past. Scientists have recorded data they need during these activities, which can strongly support their conclusion.
5) More details of the theory and experiments on the liability of solar activity affecting decay rate, this effect is related to distance between Earth and Sun, as well as where is the exposure part. More experiments need to be designed and implemented.

风静静

谢谢亲~~~
1:20
researchers found skull bones in mammal.
on one hand, they seems to surivive
on the other hand, many animals don't have them.

1:35
researchers took an experiment with many embryo brain fossils from museum, and found that interparetal was existed in all fossils.
they concluded that interparetal might appear in embryo stage so that people previously fail to recognize it.

they conduct an experiment with fish and found the interparetal acutally make up of four element, not two.

1:23
reseachers conduct an experiment to exam how social group use small details to make prediction.

1:46
reseachers conduct an experiment to determine how much information social groups need to make decision.

1:04
reseachers predict the prospective of their finding



Although clearly discernible in the embryo, shortly afterwards it fuses with other bones beyond recognition

hitherto inexplicable
interdisciplinary collaboration
feud


8:48
reseachers found they can predict the solar flare.

the significances of this prediction:
solar flare has an negative effect on satellite, astronaunt and so on.

how did reseachers gain this finding:
the distance between earth and sun has an effect on the decay.
the rate of decay changed nearly 39 hours before the solar flare.

Fighting小虾米

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草莓葡萄

follow

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4:19
P1： Unlike previous research, recent research found that the radioactive are influenced by solar activity. Since the distance between solar and earth is changed by seasonal effects.
P2:Several supporting researches for the conclusion.
P3:The terrible effects of the solar storms

evlily8783

谢谢楼主，感觉今天的越障比速度还读得顺畅些呢~怪哉~

chengzaaaa

1’04
Some skulls of mammals have been found. The skulls show the evolution of the skulls of mammals through time. Some bones disappeared.
1’39
They found the interparietal of the skulls. The change of skulls over time. The similar structure in fish and human.
1’19
Scientists study the way an individual learn the fight in the social group and behave according to that.
1’49
Scientists did an experiment to stimulate the model how an individual need to remember in order to make a prediction whether to flee or fight.
55”
The result of their study that the amount of info a monkey needs to decide. Further studies are needed.
4’28
They found a way to predict solar flares abt a day before it happen in order to protect satellites, power grids, and astronauts.
The study is based on a hypothesis published in 2006. Something having sth to do with isotope.
后面印象非常浅。。。




谢谢lz！！

miffyhui

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sparklelynn

1'21
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莽莽要上7

谢谢啦!
speed：1‘32
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越障：   6’27
讲得是有一种关于射线的方法可以用来测solar flare，然后描述了一下怎么测。后来有J和F两个提出了个新的warning system来measure，还在个什么journal上发表了results。于是data collected出来检测这个方法到底能不能测吧，方法中涉及了同位素什么的具体的忘了。然后检测出来说这个方法对solar flare 的measure是可行的。最后讲了讲solar flare有什么影响。
在具体点的就失忆了。这次没有记笔记没有回视。
先写出来呆会再读读看看我漏了什么得~~

加油！