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People always talk about all kinds of unsolved mysteries. From Amelia Earhart's strange disappearance over the Pacific in 1937, to three prisoners, Frank Morris, John Anglin and Clarence in 1962 ·Clarence Anglin legendarily escaped from Alcatraz Island in California, USA. Various mysterious stories have enriched the boring lives of the public.
Of course, these stories(2021 hermes) are not only from real history. In 1979, Douglas Adams published the first of his five series of science fiction novels-"The Hitchhiker's Guide to the Galaxy". At the end of this novel, a supercomputer named "Thinking" reveals the answer to the "ultimate question" about "life, the universe, and everything": "42". It took 7.5 million years for "Thinking" to calculate this result. But the alien who created this supercomputer in the novel is disappointing. After all, a single number is not very useful. However, "Thinking" also told the aliens that the questions they raised were too general. To find an accurate statement of the problem, the supercomputer needs to spend a long time to update itself. The new version of the computer is the earth. Interested readers can read Adams' book. The number "42" then became the foundation of geek culture (counter-mainstream culture), which led to many allusions and jokes. For example, if you enter "What is the answer to everything?" in a search engine, most of the answers that pop up are "42". Use other languages (such as French or German) or different search engines to get the same results. Since 2013, a series of computer training schools named "42 Network" have been successively established all over the world. The name is obviously derived from Adams' novels. Today, the company that founded the "42 Network" has more than 15 teaching bases. In the movie "Spider-Man: Parallel Universe", various tricks of "42" also appeared. If you click into the "42" entry on Wikipedia, you will find more interesting allusions. Actually, there are many interesting coincidences about 42, but why these coincidences exist may not be known. For example, in ancient Egyptian mythology, when a person becomes a soul after death, he needs to be judged. The deceased needs to show to 42 judges that he has not committed any of the 42 crimes. In other legends, after the Greeks defeated the Persian Empire, they sent the envoy Phidippides back to Athens from the marathon. The distance covered was about 42.195 kilometers. The distance of the modern marathon is also taken from here (and at that time, There is no such unit as "km"). Tubo has 42 generations of Zanpu, of which the first generation Nie Tri Zanpu came to the throne in about 127 BC. The reign of the last Zanpu, the 42nd Zamprandama, began in 838 AD and ended in 842 AD. The Gutenberg Bible, which was first published in Europe with movable type printing, has 42 lines per page, so it is also called the "forty-two line Bible." On March 6 this year, the "Economist" blog published an article commemorating the 42nd anniversary of the first radio drama series "The Hitchhiker's Guide to the Galaxy" in 1978 (the novel was published only after that). The article read: "Very few people will commemorate the 42nd anniversary." The author just writes casually Many people want to ask, what is the significance of Adams' 42? He succinctly answered this question in the online discussion group: "This is a joke. First, I have to find a simple and short number, and then I decide it is. Binary, thirteen, Tubo Zanpu, etc. All speculations were groundless. I was sitting at the desk, staring at the garden, and thinking, '42 is fine.' Then I typed it out. It's that simple." In binary, 42 is written as 101010, which looks simple and clever. Many fans held a party for this, on October 10, 2010 (10/10/10). But the explanation under the hexadecimal system is not so obvious. You have to answer "How much is six times nine?" to get a clue. In the hexadecimal system, (4 x 13) + 2 = 54. Except for the boring far-fetching of these computer scientists, and some coincidences found in the long river of history, what is special about the number 42 in mathematics? Mathematically unique? 42 has many interesting mathematical properties. Here are a few: The sum of the first three odd exponents of 2: 21 + 23 + 25 = 42. If we take the sum of such n odd powers as a sequence a(n) (that is, 42 = 2(3)), we get the sequence A105281. (OEIS is a website created by mathematician Neil Sloan, which collects all kinds of numbers you can't think of. You can use the first few items to search on it). In the binary system, each item of this sequence is actually to write "10" n times (1010... 10). The general formula of the sequence is a(n) = (2/3) (4n – 1). As n increases, the density of numbers tends to zero. In other words, the numbers in this series, including 42, are actually quite rare. 42 is also the sum of the first two powers of 6: 61 + 62 = 42. The corresponding sequence b(n) here corresponds to A105281 of OEIS. The general formula is b(0) = 0, b(n) = 6b(n – 1) + 6. The density of numbers also tends to 0 at infinity. 42 is a Catalan number. This kind of number is also very rare. There are only 14 Catalan numbers below one million, much less than prime numbers. Euler introduced this concept at that time to answer the question "how many triangles can a convex n-sided shape be decomposed". The first few items in the sequence are 1, 1, 2, 5, 14, 42, 132. . . It can be found in OEIS A000108. The general term formula is c(n) = (2n)! / (N! (n + 1)! ). Like the first two series, the density of numbers also approaches zero infinitely. 42 is also a fairly "practical" number, because any integer between 1 and 42, such as 20, can be decomposed like this: 20=14+6, where 14 and 6 can divide 42 (that is, a factor of 42) , The other numbers from 1 to 42 are the same, they can all be expressed as the sum of different factors of 42. The first few items of such "practical" numbers are: 1, 2, 4, 6, 8, 12, 16, 18, 20, 24, 28, 30, 32, 36, 40, 42, 48, 54, 56, 60 , 64, 66, 72 (hermes outlet). At present, we do not know the general formula of this sequence. is very interesting, but this does not mean that 42 has any unique meaning in mathematics. Its neighbors 41 and 43 also have many wonderful properties. You only need to search for any number in Wikipedia to find out its various properties. Then how can we tell whether a certain number is interesting or not? Me and two partners: Nicolas Gauvrit, a mathematician and psychologist, and Hector Zenil, a computer scientist, have studied this problem. We also tried to go towards Korotkoff's complexity, but the final result showed that the series included in OEIS are actually mainly from people's preferences. The cube sum of three numbers Computer scientists and mathematicians are sometimes interested in 42, but for them, this is just a small game in their free time, even if they change the number, they can play it. However, a piece of news not long ago attracted their attention. This is the "three cube sum" problem. In this problem, 42 is more challenging than other numbers below 100. The question is this: How to judge whether a number n can be decomposed into the form n = a3 + b3 + c3? How to find such a, b, c? Since abc may be negative, their combinations are endless, unlike the sum of squares. The absolute value of the number decomposed by the sum of squares must be smaller than the original number, so the combination is limited; and given a number, we can definitely judge whether it can be decomposed into the sum of squares. For the sum of cubes, its decomposition may be outrageous, such as 156. The decomposition of this number was discovered in 2007: 156 = 265771108075693 + (−18161093358005) 3 + (−23, 381515025762) 3 Before decomposing, we must first pay attention to a problem, that is, numbers like 9m+4 and 9m+5 cannot be decomposed (like 4, 5, 13, 14, 22, 23). In order to illustrate how difficult it is to find a solution, let us first give two examples, n=1 and n=2. When n=1, it is very simple: 13 + 13 + (–1) 3 = 1 Is there any other decomposition? The answer is yes: 93 + (–6)3 + (–8)3 = 729 + (–216) + (–512) = 1 The solution is more than that. In 1936, the German mathematician Kurt Mahler discovered that for any p, the following formula holds: (9p4) 3 + (3p – 9p4) 3 + (1 – 9p3) 3 = 1 The proof is quite simple, just need to use the binomial expansion learned in middle school: (A + B) 3 = A3 + 3A2B + 3AB2 + B3 For n=2, there are infinitely many solutions. The following formula was created by A in 1908. S. What A. S. Werebrusov discovered: (6p3 + 1) 3 + (1 – 6p3) 3 + (–6p2) 3 = 2 As long as we multiply both sides of the above formula by a perfect cube number (r3), we can get: for any perfect cube number and twice the perfect cube number, there are infinite solutions. For example, 16, it is 23 times of 2, then if p=1, there will be 143 + (–10) 3 + (–12) 3 = 16 When n=3, there are only two known solutions (as of August 2019) 13 + 13 + 13 = 3; 43 + 43 + (–5) 3 = 3 Then naturally we have to ask: Can other numbers be decomposed except for the numbers that have been proved to be indecomposable above? Computer labor In order to answer this question, mathematicians began to verify the numbers 1, 2, 3, 6, 7, 8, 9, 10, 11, 12, 15, 16 besides 9m+4 and 9m+5. . . (A060464). If a solution can be found for the previous numbers, then such a decomposition is likely to be widespread. So far, conscientious computers and computer networks have provided many results for the study of this problem. And in the end we went back to 42. In 2009, two German mathematicians, Andreas-Stephan Elsenhans (Andreas-Stephan Elsenhans) and Jörg Jahnel (Jörg Jahnel) used a method developed by Harvard University’s Noam Ersenhans The method proposed by Noam Elkies in 2000 finds a, b, and c in all the "three cube sum" problems within 1014 for n within 1000. Most n have been answered, except 33, 42, 74, 114, 165, 390, 579, 627, 633, 732, 795, 906, 921, 975. For those within 100, there are only 33, 42 and 74. In 2016, Sander Huisman (now at the University of Twente in the Netherlands), found a 74 solution: (–284650292555885) 3 + (66229832190556) 3 + (28,450105697727) 3 In 2019, Andrew Bookder of the University of Bristol found 33 solutions 88661289752875283 + (–8778405442862239) 3 + (–2736111468807040) 3 So far, Douglas Adams’ 42 is the only unsolved number remaining within 100. If the solution does not exist, 42 is really different. However, computers have not given up, they continue to search for answers. The answer will finally be revealed in 2020. Booker mentioned above and Andrew Sutherland of MIT are the main contributors. Through the charity engine platform, using the equivalent of more than one million hours of computing time, we finally got the result: 42 = (–80538738812075974) 3 + 804357581458175153 + 126021232973356313 165, 795 and 906 have also been announced recently. Now only 114, 390, 579, 627, 633, 732, 921, 975 are left below 1000. It now appears that all numbers except 9m + 4 and 9m + 5 are likely to be decomposed. In 1992, Roger Heath-Brown (Roger Heath-Brown) of Oxford University also proposed a stronger conjecture: He guessed that this decomposition is infinite for every number. However, so far, we are still a long way from proving these conjectures. This question is too difficult. Generally speaking, no algorithm can traverse all possibilities. For example, as early as 1936, Alan Turing (Alan Turing) proved that no algorithm can solve the downtime problem of all computer programs. But now the domain of the problem has reached pure mathematics that is easy to describe. If we can prove the uncertainty of this issue, it will be a big step forward. The number 42 is difficult to understand, but it is not the last step at all!
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Imagine using a mobile app to control thousands of robot doctors in your body to dance a dance... This scene does not seem far away.
Children like robots, and adults like them too. We have watched too much in the movie, but few people know how far the robots are currently? Boston's robot dog is certainly very attractive, and the robot that can spin, jump and turn around like a human is also enough to surprise the eye. However, just as there is a micro world under the macro world, micro robots are also a position that cannot be underestimated. Imagine that one day you bought a mobile phone with an app that can control thousands of micro robots in your body, monitor your health, and even dance a robot dance in your blood vessels to music. That must feel amazing! Actually, this scene does not seem far away. ——At least, you can make these robots and inject them into your body now (of course, no one will care about the consequences for the time being). And the price of these robots is really not too cheap, because they can be mass-produced, and you can "print" millions of them at once, each only costs a few cents, and they are very flexible in running! Mini robots spawned by new actuators We may have heard of many micro-robots before, such as DNA origami robots (a drug delivery robot assembled from single-stranded DNA, which relies on the circulatory system in the human body to move), multi-legged soft robots (a kind of soft silicon The robot is made of thin slices and has hundreds of hairy legs underneath, which can move efficiently in the human body with the assistance of external electromagnetic equipment), and even a healable living cell robot (a robot that uses a combination of skin cells and cardiomyocytes, Asymmetric force can be generated through the contraction of cardiomyocytes to complete specific exercise), and so on. But they all seem to be expensive, or have some shortcomings, such as not flexible enough, unable to communicate, single function, far away from reality, immune response, large size... etc. And this time, scientists(Hermes Birkin 42cm JPG Bag) at Cornell University used a very simple method to create a miniature robot that can communicate with the outside and can have very diverse functions. And its size can reach 0.1 mm or less, and it can be millions of pieces. Together, the application prospect is very promising. The core of the application of this robot is that it has a relatively mature "head"; its key breakthrough is that it has a new type of "leg". From this fascinating little thing, we can see how scientists have achieved amazing technological breakthroughs through a "small" innovation on top of existing technology. (In fact, its "head" also comes from the previous innovations of the same team members. The team can be described as "one step at a time".) Let’s talk about its head first. Of course, this part is readily available. The manufacturing process of the robot head comes from the existing semiconductor manufacturing technology. With the development of Moore's Law for more than 50 years, the semiconductor industry is using more and more advanced production processes to manufacture smaller and smaller devices. Now, these processes can put millions of transistors into a space almost the size of a single-celled paramecium. Not only that, they can also make miniature sensors, LED screens, and a bunch of packages that are too small to see. (Moore's law refers to: when the price remains the same, the number of components that can be accommodated on an integrated circuit will double about every 18 to 24 months, and the performance will also double. By Gordon Moore It was proposed in 1965, and the bottleneck is about to be reached.) This is the basis of mini robots and the basis of all current intelligent machines. We can imagine what a robot without legs looks like. Yes, it looks like the smartphone in your hand. In less than 15 years, it has taken control of the entire world. It is not only quite intelligent, with first-class communication functions, but also can be controlled with one hand. There are so many components inside that you have to put under a microscope to see the circuit on the chip clearly. The head of this mini-robot from Cornell University is similar to it, just like a cell-level smartphone, equipped with a dedicated application, and its size is tens of thousands of times smaller than a normal phone. It is called Optical Wireless Integrated Circuit (OWIC). There is a small solar cell on it. If you shine light on it, it will activate a small circuit to drive the mini LED screen to communicate with the outside world. Just like fireflies. The cool thing is that we have different OWICs, with different sensors (convert different signals into electrical signals), some can measure voltage, some can measure temperature, or some are just a flashing light spot, tell you It is there. These OWICs, as miniature security smart tags, have better recognition than fingerprints. Therefore, it is also used in other medical devices to obtain more information, and can even be put into the brain to listen to neurons and transmit signals through LED flashing. However, this is just a "head" without legs and cannot move. To be a truly mobile robot, you must have legs. Therefore, on this basis, scientists developed a set of moving legs for it, or we can call it an actuator. Observing under a microscope, you can see that it will curl up under voltage. These legs are so small that they fit the mini-heads so that the red blood cells are placed next to them, like a bagel next to chopsticks. Of course, you don't even want to see it with the naked eye. How does it move? It turned out that the power came from the platinum layer deposited on the legs-about a dozen atomic layers thick. If you put platinum in water and apply a voltage, the atoms in the water will adsorb or detach from the platinum surface—depending on the voltage level—and generate force. With the help of adsorbing or driving away the atomic layer on the platinum surface, the movement of the leg can be controlled, because the leg has only one side of the platinum layer and the other side is titanium or other materials. Because these striped legs are very thin, they can be bent and straightened repeatedly without breaking. The researchers also made a pattern with a rigid board (rigid polymer) on this basis, the gap is like a human knee and ankle, so that the legs can bend as expected and can make desired movements. In this way, a mini robot with both head and feet appeared. It has both thought and driving force. OWIC is its brain, providing us with sensors and power (converting light into voltage), and interacting with us through light. The platinum layer is the muscle that allows the robot to move around. As long as the laser is projected on different solar panels of OWIC to generate voltage, you can choose which leg to drive to move, so that it can walk. Use photolithography technology to achieve mass production But the more wonderful thing about this research is not how small and flexible the robot is, but that it can be mass-produced, which can be several million at a time. You would think that these heads and feet should be manufactured separately and then joined together. In fact, this is not the case. It uses photolithography technology, just like manufacturing traditional chips, similar to layer-by-layer printing, first "printing" on the wafer together, and then using chemicals to "pick" off the bottom substrate. The head and legs can be printed at the same time, one "print" is millions, and one "pull" is a robot army. After leaving the substrate, they are free to fold into the shape of the finished product. It is reported that on a 4-inch (about 10 cm) wafer, one million such robots can be manufactured. It only needs very low voltage and very little energy to operate, and the energy efficiency is very high. And it is very strong, can endure various acid-base environments and temperature changes over 200 degrees Celsius. You can move freely within 20 seconds after manufacturing. Since the very weak current can control the movement of their legs, they have great potential for integration with microelectronic circuits and can be seamlessly integrated with sensors and logic components (upgrading the head). This means that in the future, these robots will not only complete simple tasks such as walking, but also receive more advanced instructions from sensors and logic circuits, possess perception capabilities and programmability, and perform rich and complex activities. Even, one day, it may become a resident engineer in our body. With a tiny needle, thousands of robots can be injected into our body to perform various functions. Just like now, they can pass the needle smoothly and unscathed. However, everything has some limitations. This robot currently faces some bottlenecks. For example, at present, they have not been able to shake off the direct control of people. In other words, it is still a group of puppets. Its energy source, calculation and decision-making components are separated from the body, and researchers need to be illuminated by lasers to provide instructions for the robot. And this is still essentially a size limitation. If a fully autonomous robot can be made that combines energy storage, logic circuits and sensors, it will certainly have broader application prospects. However, it faces more stringent technical limitations on small scales. The functions that can be implemented on a 500-micron micro-robot may be extremely difficult for a 50-micron robot, and may not be possible for a 5-micron robot. Therefore, this robot is currently more of a model, showing us the extraordinary application prospects of micro robots before breaking through the technical limitations. If one day we break through all these bottlenecks, then we will truly usher in an artificial microcosm. There, countless robots live in our tissues and blood like bacteria, reminding us of possible health risks and opportunistic surgical operations; when the cells become cancerous, they gather again to fight against cancer cells one by one and pass The cell phone tells us the condition. When our children go to the wild to take a drop of water and put it under the microscope, they will see not only paramecium and bacteria, but also small robots, witnessing our strange interaction with nature. I really look forward to that day, I don’t know if you are like me. Recently, a report in "Science" magazine stated that the Square Kilometre Array (SKA) project released an analysis report on the impact of SpaceX's Starlink (Starlink Project) on the array.
The report shows that Starlink and SKA are expected to use radio frequency bands that conflict, which will make them lose their sensitivity to key information such as organic molecules and water molecules in space. Currently, radio astronomers are looking for a solution. Signal crash, Musk project has been criticized by astronomers The SKA project is the world’s largest synthetic aperture radio telescope planned by the international astronomy community. It is intended to form an information collection area of 1 square kilometer through the construction of 3000-4000 large-scale radio astronomy antenna arrays to monitor details that have never been seen in the sky. Help mankind fill the gaps in the basic understanding of the universe. Due to the perfect background of radio silence in the desert area of South Africa, the high and intermediate frequency reflector antenna required for the project will be built here and is expected to be completed by the end of the 2020s. In order to ensure SKA's observation of the sky, the use of mobile phones is even prohibited here. However, due to the existence of Starlink, these efforts may be in vain. The satellites launched by Musk’s Starlink plan, the picture is from spacex The satellites launched by Musk’s Starlink plan, the picture is from spacex "Starlink" is one of SpaceX's most ambitious plans. In January 2015, Elon Musk announced that SpaceX will launch 12,000 satellites into the earth's orbit between 2019 and 2024, creating a giant star chain composed of artificial satellites, thereby providing it globally High bandwidth, low latency, low cost satellite broadband Internet service. In Musk’s vision, Starlink can achieve a global network speed of 1G/s, and solve the problem of signal blind spots in remote and deep sea areas, eliminate information gaps, and achieve blind-spot coverage, thereby bringing about an interconnected information revolution. So far, SpaceX has launched more than 700 Starlink satellites, setting a record for the densest satellite launches in human history. However, although Starlink's space network layout has opened a new era of communication and interconnection, astronomers are concerned about the "noise" these satellites bring to the starry sky. The analysis report of SKA(replica hermes) shows that the frequency band used to transmit Internet signals in Starlink occupies a considerable frequency band in the range of 10.7 to 12.7 gigahertz, which is within the 5b frequency band. It is also the seven that need to be observed by the South African SKA array radio telescope One of the frequency bands. If the direct impact and the impact of signal leakage are taken into account, when the number of satellites launched by Starlink reaches 6,400, the sensitivity of the telescope's downlink frequency band will lose 70%. If the number of satellites reaches 100,000, the 5b frequency band will be completely unusable. Until then, SKA will lose sensitivity to the simplest amino acid-glycine (a component of protein) and other molecules. Searching for the birthplace of life and investigating the origin and evolution of the universe are important areas that SKA has developed. SKA Director General Phil Diamond (Phil Diamond) said, "If it is detected in a planetary system that is forming, it will be very interesting information." At the same time, the 5b frequency band may also be used to track water molecules in distant galaxies, helping cosmologists study how dark energy accelerates the expansion of the universe. In fact, this is not the first time Starlink has been questioned. When Starlink put the first batch of 60 satellites into orbit, the brightness of its satellites surprised astronomers. Tyler Nordgren (Tyler Nordgren) said, "This may change the natural sky." Studies have shown that the light generated by the orbit of the satellite in operation will destroy most images, and the wide-field optical measurement is the most damaged. A large number of artificial satellite constellations entering Earth orbit may have a significant adverse effect on ground and space-based astronomy research. Tripartite collaboration, looking for a way of coexistence Recently, a seminar of the United Nations Office for Outer Space Affairs (UNOOSA) discussed this analysis report of SKA, and Patricia Cooper, Vice President of SpaceX’s satellite government affairs, stated at the seminar, It is said that since August, all Starlink satellites launched have been equipped with "face shields" to reduce reflections. She also stated, "We are working hard to find a way to coexist." (https://www.2021hermes.com/sitemap/sitemapproducts.xml) With the development of replica hermes, science and technology, in recent decades, astronomical telescopes inevitably need to coexist with satellite transmitters. Radio astronomers hope that when satellites fly over radio observatories, they can turn off their transmitters, move to other bands, or point them elsewhere. Tony Beasley, director of the National Radio Astronomy Observatory in the United States, said that they have been discussing these options with SpaceX. "In the next year or two, we will try to technically coordinate with them in real time. test." But some astronomers don’t want to count on the goodwill of the company. In addition to seeking help from the United Nations Office for Outer Space Affairs, they also hope that the United Nations International Telecommunication Union (ITU) can intervene. Radio astronomer Michael Garrett, director of the Jodrellbank Centre for Astrophysics in the United Kingdom, said: “The radio spectrum is a resource that is being consumed by private companies that usually don’t value science. In my opinion, Only government intervention can stop this situation." As a result, astronomers put forward two suggestions: First, all future low-Earth orbit satellites should be designed to avoid launching beams to radio telescopes and radio silence areas; second, low-Earth orbit satellites should be well controlled for bypass signal leakage Measures. These proposals will be discussed in a series of UN subcommittees next year and further submitted to the UN Space Observation Service and the UN General Assembly. Harvard-Smithsonian Center for Astrophysics Astronomer Jonathan McDowell (Jonathan McDowell) said that if everything goes according to plan, these guidelines will be adopted by governments as licensing requirements. In terms of satellite Internet, SpaceX is not alone. Companies such as Amazon and OneWeb are all pursuing similar ambitions. If the government, satellite operators, and astronomers cannot come up with innovative solutions early through dialogue, the sky will be extremely crowded and the contradiction between satellite launches and astronomical observations will become more prominent. As an astronomer said, “These spectrum allocations represent the goals and intentions of society. Humans make them to promote commerce, defense, and various other activities. We must find a solution that meets all these requirements to some extent. Method." Recently, some friends posted on the Internet, saying that on the geomagnetic map published by NASA, just like the map attached to Weibo below, when red and blue are used to represent the strength of the Earth’s magnetic field, there is an image above the South Atlantic. The area where the strength of the earth's magnetic field is very low (blue) is particularly large. Some reports used descriptions such as "fracture", "big pit", and "dent", as well as words such as "strange", "terrible", and "serious", rendering such an abnormal development violently, even with It is a disaster for mankind, because this phenomenon is directly related to geomagnetic reversal.
Netizens speak freely (replica hermes bags) Netizens speak freely (picture from the Internet) While everyone is actively participating in the discussion, there is no need to be overly nervous about these matters. The geomagnetic anomaly in the South Atlantic has been discovered and confirmed by scientists for more than 50 years, and it has existed for many, many years before that. There is no evidence or reliable theory that it will affect our human life. You failed the exam? I drove through a red light? The next door to the Lao Wang’s house is infertility... The geomagnetic abnormality is just like the gods believed by many people. For it, our human life is too small, and the troubles of you and me are not worth mentioning. Today we will talk about this "pit" that appears on the geomagnetic map. Some friends who like mysterious stories should have heard of the mysterious "Bermuda Triangle" area. In fact, this area is the corner of the South Atlantic that we are going to talk about. Many studies believe that when airplanes and ships pass through this area, communication and navigation are prone to errors, and even electronic instruments themselves fail, which eventually leads to accidents. These may be caused by magnetic fields and the characteristics of charged particles related to them. According to the measurement of the earth’s magnetic field, there is a large area over the South Atlantic that is 30-50% weaker than other regions in the world, and the rate of weakening is 10 times faster than other regions. Since it is very different from “normal”, it is called Be the South Atlantic Anomaly. Its center is in the Atlantic Ocean between South America and Africa, covering the southwestern part of South America, the southern tip of Africa, and the southern Atlantic Ocean between the two. What is the earth's magnetic field? The magnetic field is a special substance that is invisible and intangible. It is not composed of atoms or molecules, but actually exists. There is a magnetic field around the magnet, and the interaction between the magnets is mediated by the magnetic field, so the two magnets can work without contact. Mankind has known about magnets and their magnetism a long time ago, and invented the compass, because it always has one end straight to the south (the other end naturally points to the north). And our earth is actually like a big magnet. The north pole of the magnet is near the geographic south pole, and the south pole of the magnet is near the geographic north pole. There is a deviation of about 11° between the geomagnetic axis and the geographic axis. French scholar Pierre de Maricourt (Pierre de Maricourt) discussed in 1269 that he carefully marked the orientation of the iron needles at various positions near the block magnet, that is, the direction of the magnet is used to define the direction of the magnetic field. These marks describe a lot The lines are the magnetic field lines or magnetic field lines in the figure above. He found that the magnetic field lines converge at the opposite ends of the magnet, which he called the magnetic pole. As shown in the figure below, the magnetic field lines point from the north pole (N) to the south pole (S). Later, William Gilbert argued that the earth itself is a large magnet, and its two magnetic poles are located at the south pole and the north pole, so the magnet will point in the north-south direction when viewed on the ground. The magnetic field lines indicate the direction of the magnetic field, from the north pole (N) to the south pole (S) (picture from the Internet), the magnetic field lines indicate the direction of the magnetic field, from the north pole (N) to the south pole (S) (picture from the Internet) It seems that the size and direction of the earth's magnetic field in different places on the ground will not be exactly the same. There are some commonly used parameters that express the characteristics of the magnetic field. We are used to calling them 7 elements of geomagnetism, including the total strength of the magnetic field, the strength in the horizontal direction, the strength in the vertical direction, the strength to the east, and the strength to the north. Is the component, that is, the horizontal component, the vertical component, etc. It also includes the angle with the horizontal plane (magnetic dip) and the angle between the horizontal component and the north direction (magnetic declination, that is, the angle relative to the north ). These parameters are different in different places and also change over time. Our earth’s magnetic field has a double protective effect on the earth’s biosphere: one is to avoid the invasion of high-energy charged particles from outside, and the other is to reduce the escape of charged particles in the atmosphere. Because charged particles are subject to the "Lorentz force" that makes them turn when moving in a magnetic field, they are usually "constrained" around the magnetic field, and it is difficult for charged particles with strong energy to easily "surpass" the control of the lines of magnetic force. For high-energy particles from the universe (mainly the sun), when they "blow" toward the earth and encounter the earth's magnetic field, they will be bounced off by the magnetic field, or follow the magnetic field to a place far away on the night side of the earth, and some are far away from the earth. However, some have entered the space around our earth after "exhausted hardship"; for the charged particles of the earth (mainly formed by solar radiation), the earth's magnetic field also controls them to fly around the earth, making it difficult to leave. The earth’s South Atlantic geomagnetic anomaly is mainly an anomaly of magnetic field strength, which is about half the magnitude of the magnetic field strength in the normal area at the same latitude. Now we think that the force in the core and the tilt of the magnetic axis together produce anomalies, that is to say, when the earth, as a large magnet, forms a huge magnetic field in the core, the axis of the magnet is already off. It does not coincide with the Earth’s axis, but on the side farther away from the South Atlantic Ocean, and the magnetic axis has been drifting westward. Some complex and irregular shapes and processes have brought about an "abnormal" area of geomagnetism(Hermes Evelyne On Sale). Although the South Atlantic anomaly is caused by processes inside the earth, its impact extends far beyond the surface of the earth. This area may be dangerous for low-Earth orbit satellites passing through it. If a satellite is hit by a high-energy proton, it will short-circuit and cause an event called single event upset or single event upset. This may cause the satellite function to malfunction temporarily, or cause permanent damage when a critical component is hit. The various accidents in the "Bermuda Triangle" region we mentioned earlier are also related to processes related to magnetic fields and high-energy particles. However, the dangers we are talking about are limited to hundreds of kilometers above the South Atlantic. Only thousands of kilometers high in the air will have very high-energy charged particles that can affect you, human beings and human life. They will lose energy due to collisions in the atmosphere, and they will not reach you and me at all. Due to geomagnetic anomalies in the South Atlantic anomaly, the altitude will drop to several hundred kilometers, but! What is the concept of hundreds of kilometers? Airplanes generally only fly 10-20 kilometers high! With the arrival of autumn and winter in the northern hemisphere, most countries in the northern hemisphere ushered in the "flu season." In the context of the COVID-19 pandemic this year, people are even more worried about the double attack of influenza virus and new coronavirus. Mentioned that the fall and winter are more likely to suffer from respiratory viral diseases such as flu and colds. People may first think of it because the weather is cold, and most people's activities shift from outdoors to indoors, which increases the possibility of virus transmission. But is the reason really that simple?
A few days ago, Yale University professor, HHMI researcher Dr. Akiko Iwasaki and partners published a review in the Annual Review of Virology magazine, and conducted an in-depth inventory of the causes of seasonal respiratory virus infections. The authors stated that since industrialization, people have drastically changed the impact of environmental temperature on our behavior. In many parts of the world, the temperature of offices and homes remains constant and is not affected by the seasons. Moreover, people-to-person contact in the work environment will not decrease due to seasonal changes. In industrialized countries, most people spend 90% of their lives in a relatively closed environment with poor air circulation. Therefore, the reason for the high incidence of respiratory virus infection in autumn and winter is not just the change of people's behavior. So, what factors in autumn and winter increase the risk of respiratory virus infection? What enlightenment can this bring us to prevent the new coronavirus infection this winter? Today, the WuXi AppTec content team will introduce the highlights of this review. Types of seasonal respiratory viruses At present, there are at least 9 different types of viruses that can cause common respiratory infections, and epidemiological studies in temperate regions show that most of the peaks of respiratory virus infections fluctuate with the seasons. For example, influenza virus, human coronavirus, and human respiratory syncytial virus (RSV) peak in the winter months. Adenovirus, human Boca virus, human metapneumovirus (hMPV), and rhinovirus may appear throughout the year. Some types of enteroviruses peak in summer. An interesting phenomenon is that the peaks of most respiratory viruses do not overlap. For example, epidemiological studies have found that even though RSV viruses and influenza viruses are both circulating in winter, their peaks still do not appear at the same time. The prevalence of a virus can delay the prevalence of another virus. The underlying mechanism of this interference phenomenon has not been fully clarified. Possible hypotheses include the interference of cell surface virus receptors, cell death, and human interferon (IFN) response. The influence of environmental factors on the stability and spread of respiratory viruses https://www.2021hermes.com - The transmission modes of respiratory viruses can be divided into three categories: direct or indirect contact; short-distance transmission caused by droplets or droplets; and long-distance transmission caused by aerosols. The efficiency of virus transmission through these three ways will be affected by a variety of environmental factors. Among them, the factors that have the greatest impact on long-distance transmission efficiency include temperature and air humidity. They are thought to regulate the viability of the virus by affecting the characteristics of the virus surface protein and lipid membrane. Animal experiments show that when the relative humidity of the air is too high (>60%) or too low (<40%), the virus can remain active in the droplets, and when the relative humidity of the air is between 40% and 60% The virus will be inactivated instead. The influence of environmental factors on the anti-virus defense line of the respiratory tract Because of breathing, the mucous membranes on the surface of our respiratory tract are exposed to the volatile and non-volatile pollutants in the inhaled gas and a variety of potential pathogens all the time. Therefore, the respiratory tract has also set up multiple lines of defense to prevent foreign virus infection. Studies have shown that changes in the temperature and humidity of the inhaled air with the seasons can directly affect the protective ability of the respiratory mucosa on multiple levels. If a virus entering the respiratory tract wants to infect the host, it must first contact the epithelial cells on the surface of the respiratory tract. In order to prevent the invasion of the virus, the mucus secreted by the respiratory tract can not only serve as a barrier, but also capture the epithelial cells before the virus "finds" them. Moreover, the antibacterial protein contained in mucus can also play a bactericidal effect. In addition, the cilia on the surface of epithelial cells can push the mucus that wraps the pathogen to the throat through continuous whip, and finally be spit out (or swallowed). This process is called Mucociliary Clearance (Mucociliary Clearance, MCC), which is an important means of removing pathogens and pollutants from the respiratory tract. However, dry and cold air will significantly affect the operation of this protective mechanism. Mucus needs to contain enough water to be able to act as a barrier. Dry and cold air will cause the water in the mucus to quickly lose, and the mucus becomes more viscous, more difficult to be pushed by the cilia, and therefore more difficult to remove from the respiratory tract. In addition, studies have shown that ambient temperature will also affect the speed of cilia movement. When the ambient temperature drops below 20°C, the flagging movement of mucociliary begins to slow down, and when the environment temperature reaches 5°C, the flagging movement of the cilia stops. The influence of winter environment on immune response against virus The human body's immune response to viruses includes innate immune response and adaptive immune response. The innate immune response generated in the mucosa of the respiratory tract plays a key role in preventing virus invasion. Among them, a variety of interferons (IFNs) can activate the expression of hundreds of genes to produce antiviral effects at different stages of the virus replication cycle. In recent years, studies have found that environmental factors can also affect the innate immune response against viruses. For example, human rhinovirus is one of the main causes of common colds. It mainly causes illness in winter. In vitro culture, rhinoviruses are easier to replicate at 33°C, which is the temperature of the nasal cavity in cold weather. So, why is rhinovirus easier to replicate at 33°C? Studies have found that at 33°C, rhinoviruses only trigger low levels of type 1 IFN in infected epithelial cells. The results of this study mean that exposing the nasal cavity to cold air in winter may lead to higher levels of rhinovirus replication. In addition to temperature and air humidity, the duration of sunshine also affects the immune system. In animal experiments, a shorter day life environment reduces the phagocytic capacity of white blood cells and the production of reactive oxygen species (ROS) in hamsters. The shortening of sunshine time in winter is more likely to lead to the lack of vitamin D, and the study of vitamin D-deficient mice found that their macrophages malfunctioned. These data mean that shorter sunshine hours in winter may be one of the factors leading to innate immune response disorders. For the new coronavirus, which is of particular concern to everyone, the study of its seasonality has just begun not long ago. However, studies published on the preprinted website medRxiv have shown that seasonal factors affect the severity of COVID-19 and patient mortality, and the degree of dry air is one of the important reasons pointed out by researchers. The review authors also pointed out that the outbreaks of the new coronavirus and its close relative SARS-CoV-1 both occurred in the winter months. The receptor ACE2 of these two viruses is highly expressed on type 2 alveolar cells deep in the lungs, and droplets larger than 5 microns in diameter usually cannot directly contact the alveolar cells deep in the respiratory tract. The author speculates that the winter weather may increase the viability of the virus in smaller droplets and reduce the ability to clear the mucus cilia, thereby increasing the spread of the new coronavirus. What should be done to limit the spread of respiratory viruses in winter? What insights can we gain from these studies to help us prevent respiratory virus infections and related diseases in winter? The researchers said that in addition to vaccination and the use of antiviral drugs, non-drug interventions are also very important. Healthy lifestyle habits including healthy eating, sleeping more than 7 hours a day, and good hygiene habits including frequent hand washing and wearing masks have been proven to prevent the spread of the virus and improve resistance. In addition, the researchers pointed out that an important measure that can be considered is to control the relative humidity of the indoor environment. Previous studies have shown that keeping the relative humidity at 40-60% can greatly reduce the risk of influenza virus infection. The senior author of this review, Dr. Akiko Iwasaki, posted on her Twitter (Twitter) that another function of wearing a mask is to protect the moisture and warmth of the nasal cavity, which also helps limit the spread of the virus. |
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