Editor's Note:

Chinese people believe that letters are as valuable as gold. For thousands of years, letters, across mountains and oceans, have been delivering writers' sentiments and conveyed friendship and expectations.

Xi Jinping, general secretary of the Communist Party of China (CPC) Central Committee and Chinese president, has managed to find time to reply to some letters from different parts of society and the world despite his busy work schedule.

Through his letters, Xi has corresponded with international friends from all walks of life on numerous occasions, part of a series of excellent stories of China's international exchanges in the new era. The letters have also added vivid color to the diplomacy between China and other countries.

The Global Times traced and contacted some of the recipients of Xi's letters, to hear the inspiring stories behind the letters and their communication with the president.

In this installment, Global Times reporters spoke with technicians from the Aero Engine Corporation of China (AECC) Shenyang Liming Aero-Engine Co, Ltd to learn about their stories of devoting themselves to the research and development of China's domestic aero engines and how Xi encouraged them to inherit and carry forward the spirit of a great country's craftspeople, along with a thorough review of how China gradually created its own aero engines.

"A workman must first sharpen his tools if he wants to do his work well," is a Chinese saying that emphasizes not only the importance of tools of a craft, but indicates the vital role of the craftsman who creates the tools.

"Your work is important and honorable," Chinese President Xi Jinping, who is also general secretary of the Communist Party of China (CPC) Central Committee and chairman of the Central Military Commission, told technicians at the Li Zhiqiang Class in Aero Engine Corporation of China (AECC) Shenyang Liming Aero-Engine Co Ltd, while Xi visited the corporation in 2013 to review its work in developing and producing aero engines.

A decade later, in a letter to the class on September 1, Xi spokes highly of the contribution of technicians in the research and development process of China's aero engines.

Xi emphasized that aero engines are a vital national asset and an important reflection of the country's scientific and technological strength and innovation capabilities. "I hope you will remember your mission and responsibilities, firmly uphold the aspiration of serving the aviation industry, promote the spirit of model workers and craftsmen, strive to make more technological breakthroughs, accelerate the pace of independent research and development of aviation engines, and enable Chinese aircraft to have a stronger 'Chinese heart,'" Xi said in the letter.

Until recently, aero engines had been a shortcoming in China's aircraft development, but that impression changed drastically when the Chinese People's Liberation Army (PLA) Air Force's most advanced stealth fighter jet, the J-20, made its first public appearance equipped with a pair of domestically developed engines in 2021, replacing imported engines used in the past.

Aero jeweler
The aero engine is deemed the "crown jewel" of modern industry. An aero engine is composed of tens of thousands of components of different shapes and materials. The circuit of the engine is like blood vessels around the human body, which requires a very high degree of precision to assemble and allows no room for error.

Technicians from the Li Zhiqiang Class, named after national model worker and national technical expert Li Zhiqiang, are exactly the people who are responsible for assembling aero engines and gas turbines.

"At that time, the president said our work 'is important and honorable.' He also said that the turbine vanes and blades are as valuable as diamonds. We always recall such acknowledgement and encouragement and use them as fuel to keep striving forward," said Li Zhiqiang, recalling Xi's visit a decade ago.

In a letter to Xi, Li and seven other technicians reported achievements made in strengthening technological innovation and promoting independent research and development in the aero industry over the last decade, expressing their determination to accelerate the pace of independent research and development of aero engines and build a strong aviation nation.

As the initiator among a total of eight technicians from the class who wrote the letter, Li told the Global Times that Xi's reply letter showed "extreme recognition, was encouraging, and inspirational" to the team. He shared the letter's contents to all 62 members of the team. "We must keep in mind his care, trust, and ardent expectations, firmly follow the new path of independent innovation and development of aero engines, and ensure that China's domestically made aircraft will use a stronger 'Chinese heart' in the future," he said.

One of Li's primary work principles is to "never give up before all problems are solved." In the last decade, Li, together with his colleagues, made use of various methods, including 3D simulation, to elaborately lay out processing plans for different products in accordance with their characteristics, efficiently increasing assembly quality and reducing the production period.

A typical example of the class implementing the principle is the aero engine accessory case. In the past, the case needed to be held together by several people when trying to install it in the belly of the engine, which is difficult and inefficient. This problem greatly bothered Wen Shangzhi, the current leader of the class. To solve it, Wen and his team members made use of their spare time to discuss, search materials, and conduct experiments, finally creating a new method, which obtained certification from experts and effectively improved installation efficiency.

It is in this way that the Li Zhiqiang Class found solutions and overcame obstacles one by one over the last decade, by inventing new methods, new technologies, and new tools. In total, the team solved 52 technical problems in scientific research and assembly, independently developed 312 tools and obtained more than 50 invention patents, the Global Times learned from the corporation.

When two J-20 fighter jets appeared the sky on the hot and humid opening day of the Airshow China 2021, on September 29 in Zhuhai, South China's Guangdong Province, not many spectators fully understood what they had just witnessed.

The two jets started their flight performance with a low tandem flyby above the air show site. Then, one of the aircrafts drastically pulled up and soared into the sky, while the other pulled left and performed a tight spiral maneuver before vanishing into the clouds, in a display of the aircraft's outstanding power and maneuverability.

Immediately after the flight performance, Senior Colonel Li Jikuan, commander of the J-20s' flight performance, announced at a press conference at the air show that it was the J-20's first public performance after being fitted with domestically built engines.

Experts told the Global Times that the domestically built engines provide more powerful thrust that helps the J-20 in super-maneuverability and supersonic cruise, while the engines' serrated nozzles can improve the aircraft's stealth capability.

Another important aspect of converting to use domestically built engines is that it enables mass production of aircrafts, since there are no import restrictions, experts said.

The J-20 is not the only aircraft to use domestically developed engines. Also at the Airshow China 2021, Tang Changhong, chief designer of the Y-20 large transport plane, announced that the Y-20 would be equipped with two types of domestically developed engines. After being equipped with these engines, the Y-20's capabilities have received a boost, Tang said.

Compared with imported engines, the Chinese engines could boost the Y-20's range, endurance, and cargo capacity by providing more powerful thrust and using less fuel, while also allowing the plane to take off and land on shorter runways, analysts said.

Another key member of the "20 aircraft family," the Z-20 utility helicopter, also uses domestically developed engines.

The developers of the Z-20 told the Global Times in October 2019 that the domestically developed engines are powerful enough to enable the helicopter to fly in low-oxygen plateau regions.

Observers noted that the primary battle aircrafts owned by the PLA had converted to domestically developed engines as of this year, but that does not mean China's continued efforts in aero engine development have reached their goal.

Toward stronger future

In the 2022 edition of the Airshow China, AECC showcased five variants of the Taihang series turbofan engines, which are used by different aircraft.

The Taihang engine has received continued improvements and upgrades, and its performance, reliability, safety, stealth capability, power extraction, environmental adaptability, endurance, and thrust vectoring - among other factors - have all received technical boosts.

This is expected to comprehensively enhance the aircraft's survivability and combat capabilities, and has realized the complete independent support of domestically developed engines.

One of the five Taihang engines on display has a 2D thrust vectoring control nozzle, which attracted the attention of visitors.

Li Gang, the pilot of the J-20 stealth fighter jet's first flight, said in a media interview that he would like to see the J-20 eventually be upgraded with engines with 2D thrust vectoring nozzles.

Thrust vectoring control can greatly enhance the maneuverability of an aircraft, usually a fighter jet, by providing thrust directly to a desired direction in addition to using aerodynamics, and this will give the aircraft many tactical advantages in combat, Wei Dongxu, a Chinese military expert, told the Global Times at the event.

An aero engine with a thrust vectoring control nozzle is mechanically and structurally more complex than an engine without one, and this means that thrust vectoring control usually causes a certain level of thrust loss. A 2D nozzle could lose even more thrust than a 3D nozzle. China's development of a turbofan engine with a 2D thrust vectoring control nozzle means the engine has sufficient power to manage the loss of thrust, Wei said.

A 2D nozzle usually has better radar and infrared stealth capability than a 3D nozzle, and that makes the 2D nozzle a generally better option, if the engine itself can provide enough power, Fu Qianshao, a Chinese military aviation expert, told the Global Times.

At Airshow China 2018, a J-10B thrust vector control demonstrator aircraft equipped with an engine with 3D thrust vectoring control nozzle delivered a flight performance. An engine with a 3D thrust vectoring control nozzle was also on display at the Airshow China 2022 as one of the five Taihang variants.

It is widely expected that China will continue to develop more advanced aero engines and use them on its advanced warplanes.

The growing US' geopolitical competition with Russia and China marks the end of the post-Cold War world order, US Secretary of State Antony Blinken said, speaking at the Johns Hopkins University's School of Advanced International Studies on Wednesday. "What we are experiencing now is more than a test of the post-Cold War order. It's the end of it," he noted. "Decades of relative geopolitical stability have given way to an intensifying competition with authoritarian powers, revisionist powers." This statement appears to be a rallying cry for a "new cold war." 

Since the post-Cold War order is coming to an end, what kind of new world order does the US want? Various signs indicate that the US wants major power competition and camp confrontation in order to maintain its global hegemony, even at the expense of the interests of other countries, including allies, and partner nations. However, the reality is that major power competition goes against the trend of the times and cannot solve the US' own problems and the challenges facing the world. It will only further divide the world, leading the world to slide toward a more dangerous cliff edge.

Regarding Blinken's remarks, there are two main points to consider. Firstly, Blinken was creating a sense of crisis in the world. The underlying message to US allies and other countries is that there are challengers, particularly China and Russia, who want to change the existing order. Secondly, Blinken's remarks also reflect a sense of anxiety in the US. The US is attempting to slow down China's rise through strategic competition, while hoping to sustain its hegemony without jeopardizing its own interests. However, it seems that the US has no clear solution to this dilemma. 

China is one of the beneficiaries of the existing system and does not seek to challenge or subvert this order. However, the US has viewed any legitimate demand made by China, even those that reflect the reasonable demands of the majority of developing countries, as a challenge and ill-intentioned sabotage. 

Xin Qiang, deputy director of the American Studies Center of Fudan University, believes that US irrational crackdown on China will only irritate China and other developing countries. Many developing countries share common demands with China, but the US opposes whatever China proposes and intends to strangle its legitimate right for development. This will ultimately lead to the destruction of the existing international order and be counterproductive to the US' goals.

The US believes that by containing China, it will gain an advantage. However, whatever damage they're doing to China, it also backfires on the US and even the world. 

The US now sees China as a competitor and challenger, opposing and obstructing anything that may benefit China, regardless of its impact on the US. This approach not only fails to maintain US hegemony but also leads it further away from the right direction. 

Today, the US is embroiled in simultaneous confrontations with China and Russia. The US needs to think carefully, as it will be more difficult to engage in a "new cold war" compared to the previous one. In the 1970s, the US GDP accounted for nearly one-third of the global total, but now it is only one-fourth. Its two major opponents are the nuclear power Russia and the economic powerhouse China. In order to defeat Russia, the US must ultimately dismantle its nuclear deterrence, which would be a thrilling adventure. 

As for China, the US is attempting to stifle its development by imposing unlimited technological restrictions, but it is unable to completely decouple from China economically. For the US and its main allies, China is either their largest single trading partner or one of the largest. Today, the US is a reckless strategic aggressor, attempting to unite its relatively weaker strength with its allies to wage a new cold war. It should be noted that the power of US allies has declined significantly, and the unity of the "West" is crippled due to the US transitioning from a "blood donor" to a "vampire".

The current generation of American elites arrogantly seeks to replicate the victory of the Cold War, but they will never succeed. Instead, the US will face a different ending.

Many people say that this round of Israeli-Palestinian conflict erupted quite suddenly, and on the surface, it does seem so. Hamas launched a surprise attack on the Israel's military, catching them off guard and resulting in significant casualties that have shocked the world. Israel's retaliatory actions are bound to lead to more bloodshed and escalation of violence. Even though none of us want to see this happen, it is difficult to prevent it from occurring. International peace efforts are far from strong enough in the face of the Israeli-Palestinian conflict. This is an unavoidable fact and requires a more powerful collective effort from the international community to change it.

From a deeper perspective, this conflict is not sudden and has a certain inevitability. It once again announces to the world, through bloodshed and loss of life, that if fundamental solutions are not implemented for the Palestinian issue, and if the peace process is not promoted, bloodshed and conflict will recur. This is actually quite evident, but it has long been ignored by Western countries that bear the primary responsibility and influence in the Palestinian issue.

For many years, China has repeatedly called on the international community to prioritize the Palestinian issue on the international agenda on major multilateral occasions such as the United Nations. It has emphasized the need to advance the "two-state solution" with a stronger sense of urgency. Not long ago before the outbreak of this conflict, Permanent Mission of China to the UN was still stressing this point. Now, the necessity and urgency have been elevated to another level, given the high cost paid by Palestine, Israel, and the entire Middle East.

It's necessary to recognize that the Israeli-Palestinian issue is a complex conglomerate of problems, and external interference is one of the main reasons why this problem has not been resolved and even intensifies hatred. The bias and interference by Western countries, led by the US, in the Israeli-Palestinian issue have been evident for a long time, and historical Middle East conflicts have often had US involvement behind the scenes. And after the escalation of the Israeli-Palestinian conflict, the quick decision of the US and some Western countries to take sides not only does not help solve the problem but also adds fuel to the fire. Considering the large number of innocent civilians killed and injured in the conflict over the past two days, the immediate priority of the international community should be to urge both sides to cease fire quickly in order to prevent further humanitarian disasters.

A report from the United Nations Conference on Trade and Development shows that the prolonged closure and military operations carried out by Israel during the occupation of Gaza from 2007 to 2018 have pushed Gaza's economy to the brink of collapse. Today, it has become one of the poorest and most volatile areas in the world. It can be said that this large-scale armed conflict between Palestine and Israel once again proves that the means of seeking absolute security, under the guise of peace by the US and the West, cannot achieve true peace and tranquility. It also exposes the essence of the US new Middle East strategy. We urge the US and other Western countries to stop this practice and truly participate in the Middle East peace process.

Middle East peace is by no means a road without a future. The key is to start walking the right path from now on, rather than taking the wrong path or even going back. According to media reports, this round of conflict between Palestine and Israel has already caused nearly 1,000 deaths and thousands of injuries on both sides. Moreover, the war may also spread to other countries. The latest development is that Israel and the armed group Hezbollah in Lebanon have engaged in a firefight. Many people worry whether this event will eventually lead to the "Sixth Middle East War."

At this moment, the international community should take urgent action. The United Nations issued a statement on October 7, calling it a "dangerous precipice," strongly condemning the attacks on civilians, and calling for an end to violence. UN Secretary-General António Guterres urged "all diplomatic efforts to avoid a wider conflagration." The UN Security Council plans to hold a closed-door meeting on the current situation between Palestine and Israel Sunday afternoon local time in New York to discuss solutions. Fundamentally, all parties involved in the Middle East peace process, including Palestine and Israel, must work toward creating conditions for the realization of the "two-state solution."

It has been 50 years since the Fourth Arab-Israeli War (also known as the Yom Kippur War, Ramadan War, October War) and 30 years since the signing of the Oslo Accords. War or peace? The Middle East is once again at a historical crossroads. The international community must take decisive and effective diplomatic actions to urge both sides to stop violence as soon as possible, exercise maximum restraint, and especially prevent the window of opportunity for peace from being closed by conflicts. China has always supported the convening of a larger-scale, more authoritative, and influential international peace conference to create conditions for the resumption of negotiations. This proposal is now more necessary and urgent.

Taikonauts of the Shenzhou-14 manned spaceflight mission crew are conducting their third spacewalk operation on Thursday, which marked the first extravehicular activities (EVA) after the China Space Station completed its T-shape basic structure assembly on November 3.

As of 11:16 am, taikonauts have successfully opened the airlock and the Shenzhou-14 mission commander Chen Dong first came out of the cabin. Chen will be followed by his fellow crewmember Cai Xudong for the Thursday spacewalk. Liu Yang, the only female crewmember, will be supporting them on the inside, according to the China Manned Space Agency.

During the Thursday operation, which is the seventh at the China Space Station executed by taikonauts, spacewalking taikonauts are expected to carry out works including the installation of connecting devices to bridge space station modules to facilitate future spacewalk missions and the elevation of the panorama camera on the Wentian lab module. 

The Global Times learned from mission insiders that the Thursday spacewalk will also mark a first in the use of the combination of the large and small robotic arms to support taikonauts activities all over the mega space station combination.

Having been connected at the ends, the combination of the large and small robotic arms could provide a larger operation range for taikonauts that extends to 15 meters, meaning it will be able to cover almost every corner of the space station combination, according to mission insiders. 

The second space station lab module Mengtian conducted successful transposition in orbit at 9:32 am on November 3, marking the completion of the China Space Station's T-shape basic structure assembly and a key step forward toward the completion of the space station.

Along with EG.5, a sublineage of the Omicron variant, being classified as a "variant of interest" by the World Health Organization (WHO), the topic of a third COVID-19 wave has triggered discussions among Chinese netizens in recent days with many sharing their infection experiences. Experts noted that the COVID-19 situation in China is still stable and that there is no need to panic.

Some netizens on Monday who said on social media that they had been reinfected a third time noted that their symptoms were lighter than previous infections. However, some shared different experiences.

The current COVID-19 infections are more hidden, but generally still at a relatively stable level. There isn't an obvious seasonal pattern for COVID-19 transmission, but usually it will show a small infection peak every five to six months. Generally, "the infection peak is decreasing, with no impact on the country's overall prevention work," Lu Hongzhou, head of the Third People's Hospital of Shenzhen, told the Global Times on Monday.

Generally speaking, fewer people have been infected for a third or more time in Shenzhen, South China's Guangdong Province, according to Lu.

Peng Jie, director of the Difficult Infectious Disease Center at Nanfang Hospital in Guangzhou, also in Guangdong, said since the peak reinfection wave in May, some patients who thought they had ordinary fevers only found out they had COVID-19 after nucleic acid testing. Among them, only a few were infected for the third time, and their symptoms are relatively light, said Peng, according to a report issued on the Guangdong authorities' WeChat account on Saturday.

National fever outpatient treatment and the number of severe COVID-19 cases have shown a fluctuating downward trend, according to the Chinese Center for Disease Control and Prevention (China CDC).

In July alone, the Chinese mainland reported 455 new serious cases of COVID-19, with 65 deaths. The patients had underlying health issues, and no one died of respiratory failure due to COVID-19, the China CDC said in its latest report issued on August 3. In June, the country reported 1,968 new serious cases, with 239 deaths, said the China CDC.

Based on the July data, the genome sequences of 9,591 local COVID-19 samples were all Omicron variant strains, covering 116 evolutionary branches, and the XBB variant strains were the main circulating ones, said the report released by the China CDC.

Due to the highly infectious nature of COVID-19 and the natural decrease in antibodies in individuals over time, basically most people can expect to be infected one to three times in a year. However, "for people with normal immune function, it will not have a significant impact on them," Lu explained. 

As long as the COVID-19 mutation doesn't completely break away from the Omicron subbranch, an individual will have a cross-immune memory, so when an individual encounters the EG.5 COVID-19 strain, it will respond fast and produce antibodies, according to Lu.

EG.5 was first reported in February, and designated as a variant under monitoring in July, according to a report released by the WHO on August 9. There has been a steady increase in the proportion of EG.5 reported globally. From July 17 to 23, the global prevalence of EG.5 was 17.4 percent, a notable rise from the data reported in the week from June 19 to 25, when the global prevalence of EG.5 was 7.6 percent, according to the WHO.

Lu suggested people with underlying health issues receive COVID-19 vaccinations regularly, including nasal spray vaccines or other multivalent vaccine strategies.

Here’s a good idea for the next presidential candidate debate: They can insult each other about their ignorance of statistics.

Actually, it’s a pertinent topic for political office seekers, as public opinion polls use statistical methods to measure the electorate’s support (or lack thereof) for a particular candidate. But such polls are notoriously unreliable, as Hillary Clinton found out in Michigan.

It probably wouldn’t be a very informative debate, of course — just imagine how Donald Trump would respond to a question asking what he thought about P values. Sadly, though, he and the other candidates might actually understand P values just about as well as many practicing scientists — which is to say, not very well at all.
In recent years criticism about P values — statistical measures widely used to analyze experimental data in most scientific disciplines — has finally reverberated loudly enough for the scientific community to listen. A watershed acknowledgment of P value problems appeared this week when the American Statistical Association issued a statement warning the rest of the world about the limitations of P values and their widespread misuse.

“While the p-value can be a useful statistical measure, it is commonly misused and misinterpreted,” the statistical association report stated. “This has led to some scientific journals discouraging the use of p-values, and some scientists and statisticians recommending their abandonment.”

In light of these issues, the association convened a group of experts to formulate a document listing six “principles” regarding P values for the guidance of “researchers, practitioners and science writers who are not primarily statisticians.” Of those six principles, the most pertinent for people in general (and science journalists in particular) is No. 5: “A p-value, or statistical significance, does not measure the size of an effect or the importance of a result.”

What, then, does it measure? That’s principle No. 1: “… how incompatible the data are with a specified statistical model.” But note well principle No. 2: “P-values do not measure the probability that the studied hypothesis is true, or the probability that the data were produced by random chance alone.” And therefore, always remember principle No. 3: “Scientific conclusions … or policy decisions should not be based only on whether a p-value passes a specific threshold.”

In other words, the common convention of judging a P value less than .05 to be “statistically significant” is not really a proper basis for assigning significance at all. Except that scientific journals still regularly use that criterion for deciding whether a paper gets published. Which in turn drives researchers to finagle their data to get a P value of less than .05. As a result, the scientific process is tarnished and the published scientific literature is often unreliable.
As the statistical association statement points out, this situation is far from merely of academic concern.

“The issues touched on here affect not only research, but research funding, journal practices, career advancement, scientific education, public policy, journalism, and law,” the authors point out in the report, published online March 7 in The American Statistician.

Many of the experts who participated in the process wrote commentaries on the document, some stressing that it did not go far enough in condemning P values’ pernicious influences on science.

“Viewed alone, p-values calculated from a set of numbers and assuming a statistical model are of limited value and frequently are meaningless,” wrote biostatistician Donald Berry of MD Anderson Cancer Center in Houston. He cited the serious negative impact that misuse and misinterpretation of P values has had not only on science, but also on society. “Patients with serious diseases have been harmed. Researchers have chased wild geese, finding too often that statistically significant conclusions could not be reproduced. The economic impacts of faulty statistical conclusions are great.”

Echoing Berry’s concerns was Boston University epidemiologist Kenneth Rothman. “It is a safe bet that people have suffered or died because scientists (and editors, regulators, journalists and others) have used significance tests to interpret results,” Rothman wrote. “The correspondence between results that are statistically significant and those that are truly important is far too low to be useful. Consequently, scientists have embraced and even avidly pursued meaningless differences solely because they are statistically significant, and have ignored important effects because they failed to pass the screen of statistical significance.”

Stanford University epidemiologist John Ioannidis compared the scientific community’s attachment to P values with drug addiction, fueled by the institutional rewards that accompany the publication process.

“Misleading use of P-values is so easy and automated that, especially when rewarded with publication and funding, it can become addictive,” Ioannidis commented. “Investigators generating these torrents of P-values should be seen with sympathy as drug addicts in need of rehabilitation that will help them live a better, more meaningful scientific life in the future.”

Although a handful of P value defenders can still be found among the participants in this discussion, it should be clear by now that P values, as currently used in science, do more harm than good. They may be valid and useful under certain specific circumstances, but those circumstances are rarely relevant in most experimental contexts. As Berry notes, statisticians can correctly define P values in a technical sense, but “most statisticians do not really understand the issues in applied settings.”

In its statement, the statistical association goes a long way toward validating the concerns about P values that have been expressed for decades by many critical observers. This validation may succeed in initiating change where previous efforts have failed. But that won’t happen without identifying some alternative to the P value system, and while many have been proposed, no candidate has emerged as an acceptable nominee for a majority of the scientific world’s electorate. So the next debate should not be about P values — it should be about what to replace them with.

NEW YORK — Lip-readers’ minds seem to “hear” the words their eyes see being formed. And the better a person is at lipreading, the more neural activity there is in the brain’s auditory cortex, scientists reported April 4 at the annual meeting of the Cognitive Neuroscience Society.

Earlier studies have found that auditory brain areas are active during lipreading. But most of those studies focused on small bits of language — simple sentences or even single words, said study coauthor Satu Saalasti of Aalto University in Finland. In contrast, Saalasti and colleagues studied lipreading in more natural situations. Twenty-nine people read the silent lips of a person who spoke Finnish for eight minutes in a video. “We can all lip-read to some extent,” Saalasti said, and the participants, who had no lipreading experience, varied widely in their comprehension of the eight-minute story.

In the best lip-readers, activity in the auditory cortex was quite similar to that evoked when the story was read aloud, brain scans revealed. The results suggest that lipreading success depends on a person’s ability to “hear” the words formed by moving lips, Saalasti said.

To rewrite an Alanis Morissette song, the brain has a funny way of waking you up (and putting you to sleep). Isn’t it ionic? Some scientists think so.

Changes in ion concentrations, not nerve cell activity, switch the brain from asleep to awake and back again, researchers report in the April 29 Science. Scientists knew that levels of potassium, calcium and magnesium ions bathing brain cells changed during sleep and wakefulness. But they thought neurons — electrically active cells responsible for most of the brain’s processing power — drove those changes.
Instead, the study suggests, neurons aren’t the only sandmen or roosters in the brain. “Neuromodulator” brain chemicals, which pace neuron activity, can bypass neurons altogether to directly wake the brain or lull it to sleep by changing ion concentrations.

Scientists hadn’t found this direct connection between ions and sleep and wake before because they were mostly focused on what neurons were doing, says neuroscientist Maiken Nedergaard, who led the study. She got interested in sleep after her lab at the University of Rochester in New York found a drainage system that washes the brain during sleep (SN: 11/16/13, p. 7).When measuring changes in the fluid between brain cells, Nedergaard and colleagues realized that ion changes followed predictable patterns: Potassium ion levels are high when mice (and presumably people) are awake, and drop during sleep. Calcium and magnesium ions follow the opposite pattern; they are higher during sleep and lower when mice are awake.
In the study, Nedergaard’s group administered a “wake cocktail” of neuromodulator chemicals to mouse brains. Levels of potassium ions floating between brain cells increased rapidly after the treatment, the researchers found. That ion change happened even when the researchers added tetrodotoxin to stop neuron activity. The results suggest that the brain chemicals — norepinephrine, acetylcholine, dopamine, orexin and histamine — directly affect ion levels with no help from neurons. Exactly how the chemicals manage ion levels still isn’t known.
Similar changes happen under anesthesia. When awake mice were anesthetized, potassium ion levels in their brains dropped sharply, while levels of calcium and magnesium rose, the researchers found. As mice awoke from anesthesia, potassium ion levels rose quickly. But calcium and magnesium levels took longer to drop. As a result, the mice “are totally confused,” says Nedergaard. “They bump into their cages, they run around and they don’t know what they are doing.”

Those results may help explain why people are groggy after waking up from anesthesia; their ion levels haven’t returned to “awake” levels yet, says Amita Sehgal, a sleep researcher at the University of Pennsylvania School of Medicine.

Learning more about how ions affect wake and sleep may eventually lead to a better understanding of sleep, consciousness and coma, Nedergaard says.

But, says neuroscientist Chiara Cirelli of the University of Wisconsin‒Madison, practical implications of the work, such as improved sleep drugs, are probably far in the future. “How they make use of it will take some time, but just knowing this is certainly very eye-opening.” It would be interesting to find out what happens to ion concentrations during REM sleep, when neurons are as active as they are when a person is awake, she says.

techstyle

Through July 10
Museum of Fine Arts, Boston

You wouldn’t expect wardrobe classics like leather jackets or denim jeans at an exhibit celebrating fashion at its most forward. But “#techstyle” at the Museum of Fine Arts in Boston features those sartorial mainstays and others, each with a technological twist.

A feast for the eyes, the diversity of pieces is matched by the diversity of artists and approaches. Yet a single theme unites: The fusion of technology and fashion will increasingly influence both. Visitors are introduced to this theme via a room featuring works by prominent designers already known for merging fashion and tech: A digitally printed silk dress by Alexander McQueen hangs next to a fiberglass “airplane dress” by Hussein Chalayan that has flaps that open and shut via remote control.
The largest part of the exhibit focuses on how technology is changing design and construction strategies. In addition to clothes made with mainstream techniques like laser-cutting, several 3-D printed garments are on display. These include a kinematic dress made of more than 1,600 interlocking pieces that can be customized to a wearer’s body via a 3-D scan. The dress comes off the printer fully assembled. Other pieces are made with technologies still being developed, such as the laser-welded fabrics from sustainable textile researcher Kate Goldsworthy.
The real standouts are in the “Performance” section, which displays attire that uses data from the immediate environment to generate some visible aspect of the garment. These interactive pieces “reveal something to the eye that you wouldn’t see normally, something that science often captures with graphs and charts,” says Pamela Parmal, a curator of the exhibit. For instance, the interactive dress “Incertitudes” is adorned with pins that flex in response to nearby voices, creating waves in the fabric; a dress embedded with thousands of tiny LEDs can display tweeted messages or other illuminated patterns.
And there are two leather jackets that, at first glance, look like their innovation is merely a stylish cut. But the jackets are coated in reactive inks that shimmer with iridescent colors in response to the wind and heat generated by heat guns in the display case. (These creations were born after designer and trained chemist Lauren Bowker used the reactive compounds to reveal the aerodynamics of race cars in a wind tunnel in a project for Formula One.)

Visitors seeking in-depth explanations of the science behind the fashions will have to look elsewhere. But “#techstyle” still has something for everyone, whether fashionista or engineer. And while the fashions represented are all cutting edge, the show harks back to an era when clothes were custom-made. Technology might have brought us mass-produced cookie-cutter clothing, but it can also enable clothing tailored to the individual.

From within the dark confines of the skull, the brain builds its own version of reality. By weaving together expectations and information gleaned from the senses, the brain creates a story about the outside world. For most of us, the brain is a skilled storyteller, but to spin a sensible yarn, it has to fill in some details itself.

“The brain is a guessing machine, trying at each moment of time to guess what is out there,” says computational neuroscientist Peggy Seriès.
Guesses just slightly off — like mistaking a smile for a smirk — rarely cause harm. But guessing gone seriously awry may play a part in mental illnesses such as schizophrenia, autism and even anxiety disorders, Seriès and other neuroscientists suspect. They say that a mathematical expression known as Bayes’ theorem — which quantifies how prior expectations can be combined with current evidence — may provide novel insights into pernicious mental problems that have so far defied explanation.
Bayes’ theorem “offers a new vocabulary, new tools and a new way to look at things,” says Seriès, of the University of Edinburgh.

Experiments guided by Bayesian math reveal that the guessing process differs in people with some disorders. People with schizophrenia, for instance, can have trouble tying together their expectations with what their senses detect. And people with autism and high anxiety don’t flexibly update their expectations about the world, some lab experiments suggest. That missed step can muddy their decision-making abilities.
Given the complexity of mental disorders such as schizophrenia and autism, it is no surprise that many theories of how the brain works have fallen short, says psychiatrist and neuroscientist Rick Adams of University College London. Current explanations for the disorders are often vague and untestable. Against that frustrating backdrop, Adams sees great promise in a strong mathematical theory, one that can be used to make predictions and actually test them.

“It’s really a step up from the old-style cognitive psychology approach, where you had flowcharts with boxes and labels on them with things like ‘attention’ or ‘reading,’ but nobody having any idea about what was going on in [any] box,” Adams says.

Applying math to mental disorders “is a very young field,” he adds, pointing to Computational Psychiatry, which plans to publish its first issue this summer. “You know a field is young when it gets its first journal.”

A mind for math
Bayesian reasoning may be new to the mental illness scene, but the math itself has been around for centuries. First described by the Rev. Thomas Bayes in the 18th century, this computational approach truly embraces history: Evidence based on previous experience, known as a “prior,” is essential to arriving at a good answer, Bayes argued. He may have been surprised to see his math meticulously applied to people with mental illness, but the logic holds. To make a solid guess about what’s happening in the world, the brain must not rely just on current input from occasionally unreliable senses. The brain must also use its knowledge about what has happened before. Merging these two streams of information correctly is at the heart of perceiving the world as accurately as possible.

Bayes figured out a way to put numbers to this process. By combining probabilities that come from prior evidence and current observations, Bayes’ formula can be used to calculate an overall estimate of the likelihood that a given suspicion is true. A properly functioning brain seems to do this calculation intuitively, behaving in many cases like a skilled Bayesian statistician, some studies show (SN: 10/8/11, p. 18).

This reckoning requires the brain to give the right amount of weight to prior expectations and current information. Depending on the circumstances, those weights change. When the senses falter, for instance, the brain should lean more heavily on prior expectations. Say the mail carrier comes each day at 4 p.m. On a stormy afternoon when visual cues are bad, we rely less on sight and more on prior knowledge to guess that the late-afternoon noise on the front porch is probably the mail carrier delivering letters. In certain mental illnesses, this flexible balancing act may falter.

People with schizophrenia often suffer from hallucinations and delusions, debilitating symptoms that arise when lines between reality and imagination blur. That confusion can lead to hearing voices that aren’t there and believing things that can’t possibly be true. These departures from reality could arise from differences in how people integrate new evidence with previous beliefs.
There’s evidence for such distorted calculations. People with schizophrenia don’t fall for certain visual illusions that trick most people, for instance. When shown a picture of the inside of a hollowed-out face mask, most people’s brains mistakenly convert the image to a face that pops outward off the page. People with schizophrenia, however, are more likely to see the face as it actually is — a concave mask. In that instance, people with schizophrenia give more weight to information that’s coming from their eyes than to their expectation that noses protrude from the rest of the face.
To complicate matters, the opposite can be true, too, says neuropsychologist Chris Frith of the Wellcome Trust Centre for Neuroimaging at University College London. “In this case, their prior is too weak, but in other cases, their prior is too strong,” he says.

In a recent study, healthy people and those who recently began experiencing psychosis, a symptom of schizophrenia, were shown confusing shadowy black-and-white images. Participants then saw color versions of the images that were easier to interpret. When shown the black-and-white images again, people with early psychosis were better at identifying the images, suggesting that they used their prior knowledge — the color pictures — to truly “see” the images. For people without psychosis, the color images weren’t as much help. That difference suggests that the way people with schizophrenia balance past knowledge and present observations is distinct from the behavior of people without the disorder. Sometimes the balance tips too far — in either direction.

In a talk at the annual Computational and Systems Neuroscience meeting in February in Salt Lake City, Seriès described the results of a different visual test: A small group of people with schizophrenia had to describe which way a series of dots were moving on a screen. The dots moved in some directions more frequently than others — a statistical feature that let the scientists see how well people could learn to predict the dots’ directions. The 11 people with schizophrenia seemed just as good at learning which way the dots were likely to move as the 10 people without, Seriès said. In this situation, people with schizophrenia seemed able to learn priors just fine.

But when another trick was added, a split between the two groups emerged. Sometimes, the dots were almost impossible to see, and sometimes, there were no dots at all. People with schizophrenia were less likely to claim that they saw dots when the screen was blank. Perhaps they didn’t hallucinate dots because of the medication they were on, Seriès says. In fact, very early results from unmedicated people with schizophrenia suggest that they actually see dots that aren’t there more than healthy volunteers.
Preliminary results so far on schizophrenia are sparse and occasionally conflicting, Seriès admits. “It’s the beginning,” she says. “We don’t understand much.”

The research is so early that no straightforward story exists yet. But that’s not unexpected. “If 100 years of schizophrenia research have taught us anything, it’s that there’s not going to be a nice, simple explanation,” Adams says. But using math to describe how people perceive the world may lead to new hunches about how that process goes wrong in mental illnesses, he argues.

“You can instill expectations in subjects in many different ways, and you can control what evidence they see,” Adams says. Bayesian theory “tells you what they should conclude from those prior beliefs and that evidence.” If their conclusions diverge from predictions, scientists can take the next step. Brain scans, for instance, may reveal how the wrong answers arise. With a clear description of these differences, he says, “we might be able to measure people’s cognition in a new way, and diagnose their disorders in a new way.”

Now vs. then
The way the brain combines incoming sensory information with existing knowledge may also be different in autism, some researchers argue. In some cases, people with autism might put excess weight on what their senses take in about the world and rely less on their expectations. Old observations fit with this idea. In the 1960s, psychologists had discovered that children with autism were just as good at remembering nonsense sentences (“By is go tree stroke lets”) as meaningful ones (“The fish swims in the pond”). Children without autism struggled to remember the non sequiturs. But the children with autism weren’t thrown by the random string of words, suggesting that their expectations of sentence meaning weren’t as strong as their ability to home in on each word in the series.

Another study supports the notion that sensory information takes priority in people with autism. People with and without autism were asked to judge whether a sight and a sound happened at the same time. They saw a white ring on a screen, and a tone played before, after or at the same time. Adults without autism were influenced by previous trials in which the ring and tone were slightly off. But adults with autism were not swayed by earlier trials, researchers reported in February in Scientific Reports.

This literal perception might get in the way of speech perception, Marco Turi of the University of Pisa in Italy and colleagues suggest. Comprehending speech requires a listener to mentally stitch together sights and sounds that may not arrive at the eyes and ears at the same time. Losing that flexibility could make speech harder to understand.

A different study found that children with autism perceive moving dots more clearly than children without autism (SN Online: 5/5/15). The brains of people with autism seem to prioritize incoming sensory information over expectations about how things ought to work. Elizabeth Pellicano of University College London and David Burr of the University of Western Australia in Perth described the concept in 2012 in an opinion paper in Trends in Cognitive Sciences. Intensely attuned to information streaming in from the senses, people with autism experience the world as “too real,” Pellicano and Perth wrote.

New data, however, caution against a too-simple explanation. In an experiment presented in New York City in April at the annual meeting of the Cognitive Neuroscience Society, 20 adults with and without autism had to quickly hit a certain key on a keyboard when they saw its associated target on a screen. Their job was made easier because the targets came in a certain sequence. All of the participants improved as they learned which keys to expect. But when the sequence changed to a new one, people with autism faltered. This result suggests that they learned prior expectations just fine, but had trouble updating them as conditions changed, said cognitive neuroscientist Owen Parsons of the University of Cambridge.
Distorted calculations — and the altered versions of the world they create — may also play a role in depression and anxiety, some researchers think. While suffering from depression, people may hold on to distorted priors — believing that good things are out of reach, for instance. And people with high anxiety can have trouble making good choices in a volatile environment, neuroscientist Sonia Bishop of the University of California, Berkeley and colleagues reported in 2015 in Nature Neuroscience.

In their experiment, people had to choose a shape, which sometimes  came with a shock. People with low anxiety quickly learned to avoid the shock, even when the relationship between shape and shock changed. But people with high anxiety performed worse when those relationships changed, the researchers found. “High-anxious individuals didn’t seem able to adjust their learning to handle how volatile or how stable the environment was,” Bishop says.
Scientists can’t yet say what causes this difficulty adjusting to a new environment in anxious people and in people with autism. It could be that once some rule is learned (a sequence of computer keys, or the link between a shape and a shock), these two groups struggle to update that prior with newer information.

This rigidity might actually contribute to anxiety in the first place, Bishop speculates. “When something unexpected happens that is bad, you wouldn’t know how to respond,” and that floundering “is likely to be a huge source of anxiety and stress.”

Recalculating
“There’s been a lot of frustration with a failure to make progress” on psychiatric disorders, Bishop says. Fitting mathematical theories to the brain may be a way to move forward. Researchers “are very excited about computational psychiatry in general,” she says.

Computational psychiatrist Quentin Huys of the University of Zurich is one of those people. Math can help clarify mental illnesses in a way that existing approaches can’t, he says. In the March issue of Nature Neuroscience, Huys and colleagues argued that math can demystify psychiatric disorders, and that thinking of the brain as a Bayesian number cruncher might lead to a more rigorous understanding of mental illness. Huys says that a computational approach is essential. “We can’t get away without it.” If people with high anxiety perform differently on a perceptual test, then that test could be used to both diagnose people and monitor how well a treatment works, for instance.

Scientists hope that a deeper description of mental illnesses may lead to clearer ways to identify a disorder, chart how well treatments work and even improve therapies. Bishop raises the possibility of developing apps to help people with high anxiety evaluate situations  — outsourcing the decision making for people who have trouble. Frith points out that cognitive behavioral therapy could help depressed people recalculate their experiences by putting less weight on negative experiences and perhaps breaking out of cycles of despondence.

Beyond these potential interventions, simply explaining to people how their brains are working might ease distress, Adams says. “If you can give people an explanation that makes sense of some of the experiences they’ve had, that can be a profoundly helpful thing,” he says. “It destigmatizes the experience.”