Shenzhou-14 taikonauts meet press for first time since returning to Earth

Seventy-five days after having returned to the ground, the Shenzhou-14 crew members met the press on Friday and were in good spirits. They were also in good physical and mental shape, said health experts at the press conference, noting that they have now moved into the recovery observation stage and will be able to return to normal soon.

The recovery of normal body function for the taikonauts after they returned from space consists of three stages - quarantine, convalescence and observation - according to health experts speaking at the press conference on Friday.

The Shenzhou-14 crew has completed the first two stages, showing a stable emotional status and good mental condition, and their body weight has stabilized at pre-flight level. The muscle strength, endurance and cardiorespiratory reserves have been further restored, achieving the expected results.

They have now moved into the third stage of recovery observation. After an overall evaluation, the three taikonauts will be able to return to normal training and work.

After concluding their six-month stay at the China Space Station and completing the first direct handover in orbit in the country's history, Chen Dong, Liu Yang and Cai Xuzhe, the three taikonauts of the Shenzhou-14 safely returned to Earth on December 4, 2022.

It marked the first return mission after the completion of the China Space Station's T-shape basic structure.

Local govts support state-owned enterprises expanding hiring of graduates, expected to help alleviate unemployment pressure

Many localities have issued policies to encourage state-owned enterprises to play an exemplary role in stabilizing employment and expand recruitment of college graduates, with some provinces and cities requiring no less than half of the hiring quota at state-owned enterprises be dedicated to college graduates.

The office of the Guangdong Provincial People's Government recently published a notice on optimizing and adjusting stable employment policies and measures to promote development and benefit people's livelihood. Showing clear support for state-owned enterprises expanding the scale of recruitment, the notice pointed out that the number of new college graduates recruited by state-owned enterprises in the province this year should be no lower than that of 2022.

Additionally, East China's Anhui Province also issued a notice requiring state-owned enterprises to recruit at least 50 percent of fresh graduates to ensure that the number of college graduates accepted by state-owned enterprises remains stable.

Besides this, the provinces of Hunan, Gansu and Jiangxi have made similar notices. Among them, Central China's Hunan Province requires that provincial state-owned enterprises accept more than 4,700 graduates, while Northwest China's Gansu requires provincial state-owned enterprises to recruit more than 5,000 college graduates in 2023. Meanwhile, provincial state-owned enterprises funded and supervised by the Jiangxi government are set to recruit no less than 5,000 college graduates this year.

The number of college graduates is expected to reach 11.58 million before the end of 2023, an increase of 820,000, according to estimates by China's Ministry of Education. 

South China's Hainan Province proposed in July that state-owned enterprises should play a role in attracting young employees and ensure that no less than 1,000 college graduates are recruited by the end of 2023, while East China's Fujian Province is requiring the implementation of a one-time increase at state-owned enterprises to ensure that the number of college graduates recruited exceeds that of 2022.

An employee at PetroChina's Beijing branch surnamed Li told the Global Times on Sunday that more than 80 percent of new hires at the branch office in 2023 have been graduates. Moreover, a staff member surnamed Zhao with the Industrial and Commercial Bank of China's research and development center in Beijing told the Global Times that the recruitment rate of graduates at the company in 2023 reached 90 percent.

The demand for state-owned enterprises to expand the scale of recruitment is in response to graduate demand and aims to alleviate the current problem of comparatively low youth employment, Xiong Bingqi, director of the 21st Century Education Research Institute in Beijing, told the Global Times on Sunday. 

According to Xinhua News Agency, as of August 11, the number of college graduates recruited by central enterprises and state-owned enterprises under the national asset supervision system has exceeded the same period in 2022. With the summer recruitment of state-owned enterprises gradually underway, it is expected that the recruitment volume will continue to increase in the future.

The State-owned Assets Supervision and Administration Commission of the State Council has also made arrangements for the recruitment of college graduates by state-owned enterprises in 2024 at a meeting held in July.

The meeting required central enterprises and local state-owned enterprises to strive to complete the recruitment plan for the 2024 college graduates by the end of August, and gradually provide a batch of high-quality positions in September and October, in order to identify a group of high-quality target candidates as early as possible.

According to the Xinhua News Agency, as of August 11, the number of college graduates recruited by state-owned enterprises under the national asset supervision system has exceeded the same period in 2022. With the summer recruitment of state-owned enterprises gradually underway, it is expected that recruitment volume will continue to increase in the future.

The State-owned Assets Supervision and Administration Commission of the State Council has made arrangements for the recruitment of college graduates by state-owned enterprises in 2024 at a meeting held in July.

The meeting required central and local state-owned enterprises to strive to complete recruitment plans for the 2024 college graduates by the end of August, and gradually provide a batch of high-quality positions in September and October, in order to identify a group of high-quality target candidates as early as possible.

Hubble telescope snaps stunning pic for its 26th birthday

Time to add another gorgeous space photo to the Hubble Space Telescope’s list of greatest hits. For the orbiting observatory’s 26th anniversary in space, astronomers snapped a picture of the Bubble Nebula, a seven-light-year-wide pocket of gas being blown away by a blazing massive star about 7,100 light-years away in the constellation Cassiopeia.

The star responsible for the bubble is young, just 4 million years old, and about 45 times as massive as our sun. It is so hot and bright that it launches its own gas into space at more than 6 million kilometers per hour. The vibrant colors in the nebula represent the elements oxygen, hydrogen and nitrogen.

Hubble launched April 24, 1990, aboard the space shuttle Discovery. A series of visits by astronauts have kept the aging telescope’s suite of cameras, spectrometers and ancillary equipment up-to-date and operating well into its third decade.

Limestone world gobbled by planet-eating white dwarf

SAN DIEGO — A remote planet — the first with hints of a limestone shell — has been shredded by its dead sun, a new study suggests.

A generous heaping of carbon is raining down on a white dwarf, the exposed core of a dead star, astrophysicist Carl Melis of the University of California, San Diego said June 13 at a meeting of the American Astronomical Society. The carbon — along with a dash of other elements such as calcium, silicon and iron — is probably all that remains of a rocky planet, torn apart by its dying sun’s gravity. Many other white dwarfs show similar signs of planetary cannibalism (SN Online: 10/21/15), but none are as flooded with carbon atoms as this one.

A planet slathered in calcium carbonate, a mineral found in limestone, could explain the shower of carbon as well as the relative amounts of other elements, said Melis. He and Patrick Dufour, an astrophysicist at the University of Montreal, estimate that calcium carbonate could have made up to 9 percent of the doomed world’s mass.

While a limestone-encrusted world is a first, it’s not shocking, says Melis. The recipe for calcium carbonate is just carbon and calcium in the presence of water. “If you have those conditions, it’s going to form,” he says.

“The real interesting thing is the carbon,” Melis adds. Carbon needs to be frozen — most likely as carbon dioxide — to be incorporated into a forming planet. But CO2 freezes far from a star, beyond where researchers suspect rocky planets are assembled. A limestone planet could have formed in an unexpected place and later wandered in while somehow retaining its carbon stores in the warm environs closer to its sun. Or the carbon might have been delivered to the world after it formed. But, Melis says, it’s not clear how either would happen.

Courts’ use of statistics should be put on trial

The Rev. Thomas Bayes was, as the honorific the Rev. suggests, a clergyman. Too bad he wasn’t a lawyer. Maybe if he had been, lawyers today wouldn’t be so reluctant to enlist his mathematical insights in the pursuit of justice.

In many sorts of court cases, from whether talcum powder causes ovarian cancer to The People v. O.J. Simpson, statistics play (or ought to play) a vital role in evaluating the evidence. Sometimes the evidence itself is statistical, as with the odds of a DNA match or the strength of a scientific research finding. Even more often the key question is how evidence should be added up to assess the probability of guilt. In either circumstance, the statistical methods devised by Bayes are often the only reasonable way of drawing an intelligent conclusion.

Yet the courts today seem suspicious of statistics of any sort, and not without reason. In several famous cases, flawed statistical reasoning has sent innocent people to prison. But in most such instances the statistics applied in court have been primarily the standard type that scientists use to test hypotheses (producing numbers for gauging “statistical significance”). These are the same approaches that have been so widely criticized for rendering many scientific results irreproducible. Many experts believe Bayesian statistics, the legacy of a paper by Bayes published posthumously in 1763, offers a better option.

“The Bayesian approach is especially well suited for a broad range of legal reasoning,” write mathematician Norman Fenton and colleagues in a recent paper in the Annual Review of Statistics and Its Application.

But Bayes has for the most part been neglected by the legal system. “Outside of paternity cases its impact on legal practice has been minimal,” say Fenton, Martin Neil and Daniel Berger, all of the School of Electronic Engineering and Computer Science at Queen Mary University London.

That’s unfortunate, they contend, because non-Bayesian statistical methods have severe shortcomings when applied in legal contexts. Most famously, the standard approach is typically misinterpreted in a way known as the “prosecutor’s fallacy.”

In formal logical terms, the prosecutor’s fallacy is known as “the error of the transposed conditional,” as British pharmacologist David Colquhoun explains in a recent blog post. Consider a murder on a hypothetical island, populated by 1,000 people. Police find a DNA fragment at the crime scene, a fragment that would be found in only 0.4 percent of the population. For no particular reason, the police arrest Jack and give him a DNA test. Jack’s DNA matches the crime scene fragment, so he is charged and sent to trial. The prosecutor proclaims that since only 0.4 percent of innocent people have this DNA fragment, it is 99.6 percent certain that Jack is the killer — evidence beyond reasonable doubt.
But that reasoning is fatally (for Jack) flawed. Unless there was some good reason to suspect Jack in the first place, he is just one of 1,000 possible suspects. Among those 1,000, four people (0.4 percent) should have the same DNA fragment found at the crime scene. Jack is therefore just one of four possibilities to be the murderer — so the probability that he’s the killer is merely 25 percent, not 99.6 percent.

Bayesian reasoning averts this potential miscarriage of justice by including the “prior probability” of guilt when calculating the probability of guilt after the evidence is in.

Suppose, for instance, that the crime in question is not murder, but theft of cupcakes from a bakery employing 100 people. Security cameras reveal 10 employees sneaking off with the cupcakes but without a good view of their identities. So the prior probability of any given employee’s guilt is 10 percent. Police sent to investigate choose an employee at random and conduct a frosting residue test known to be accurate 90 percent of the time. If the employee tests positive, the police might conclude there is therefore a 90 percent probability of guilt. But that’s another example of the prosecutor’s fallacy — it neglects the prior probability. Well-trained Bayesian police would use the formula known as Bayes’ theorem to calculate that given a 10 percent prior probability, 90 percent reliable evidence yields an actual probability of guilt of only 50 percent.

You don’t even need to know Bayes’ formula to reason out that result. If the test is 90 percent accurate, it will erroneously identify nine out of the 90 innocent employees as guilty, and it would identify only nine out of the 10 truly guilty employees. If the police tested all 100 people, then, 18 would appear guilty, but nine of those 18 (half of them) would actually be innocent. So a positive frosting test means only a 50 percent chance of guilt. Bayesian math would in this case (and in many real life cases) prevent a rush to injustice.

“Unfortunately, people without statistical training — and this includes most highly respected legal professionals — find Bayes’ theorem both difficult to understand and counterintuitive,” Fenton and colleagues lament.

One major problem is that real criminal cases are rarely as simple as the cupcake example. “Practical legal arguments normally involve multiple hypotheses and pieces of evidence with complex causal dependencies,” Fenton and colleagues note. Adapting Bayes’ formula to complex situations is not always straightforward. Combining testimony and various other sorts of evidence requires mapping out a network of interrelated probabilities; the math quickly can become much too complicated for pencil and paper — and, until relatively recently, even for computers.

“Until the late 1980s there were no known efficient computer algorithms for doing the calculations,” Fenton and colleagues point out.

But nowadays, better computers — and more crucially, better algorithms — are available to compute the probabilities in just the sorts of complicated Bayesian networks that legal cases present. So Bayesian math now provides the ideal method for weighing competing evidence in order to reach a sound legal judgment. Yet the legal system seems unimpressed.

“Although Bayes is the perfect formalism for this type of reasoning, it is difficult to find any well-reported examples of the successful use of Bayes in combining diverse evidence in a real case,” Fenton and coauthors note. “There is a persistent attitude among some members of the legal profession that probability theory has no role in the courtroom.”

In one case in England, in fact, an appeals court denounced the use of Bayesian calculations, asserting that members of the jury should apply “their individual common sense and knowledge of the world” to the evidence presented.

Apart from the obvious idiocy of using common sense to resolve complex issues, the court’s call to apply “knowledge of the world” to the evidence is exactly what Bayesian math does. Bayesian reasoning provides guidance for applying prior knowledge properly in assessing new knowledge (or evidence) to reach a sound conclusion. Which is what the judicial system is supposed to do.

Bayesian statistics offers a technical tool for avoiding fallacious reasoning. Lawyers should learn to use it. So should scientists. And then maybe then someday justice will be done, and science and the law can work more seamlessly together. But as Fenton and colleagues point out, there remain “massive cultural barriers between the fields of science and law” that “will only be broken down by achieving a critical mass of relevant experts and stakeholders, united in their objectives.”