How burning bay leaves can help. How can the last consensus mechanism proposed by Vitalik Buterin work?
Domestic and foreign doctors claim that the electrocardiogram as such is a procedure that is harmless to the human body. Its harm lies only in the off-system use of the ECG - an unscheduled examination using this device can contribute to the incorrect diagnosis of the patient.
When is it better not to take this test?
Candidate of Medical Sciences A.V. Rodionov believes that there are a lot of situations when it is not necessary to take an ECG, it is superfluous. This is especially true for children and young people - each growing organism has a lot of individual developmental characteristics, and if a competent attending physician did not prescribe an electrocardiogram, you should not engage in amateur activities.
Rodionov assures that healthy man does not need an ECG - passing this procedure as unnecessary is harmful in terms of possible subsequent incorrect interpretation of the results: a low-qualified physician can “consider” a “serious pathology” on the heartbeat gradation tape, which then will have to be “seriously treated”.
Anton Vladimirovich is convinced that a banal measurement of pressure and familiarization with the results of banal analyzes is enough for a medical professional to decide whether the patient should do an ECG or not.
Is a cardiogram dangerous in itself?
Rakesh K. Pai, MD, a cardiologist, says that an electrocardiogram "can show heart problems that would make a stress ECG unsafe." In fact, Pai's colleagues in this sense are more in favor of professional suitability - Domenico Corrado, Cristina Basso, Antonio Pellecchia and Gaetano Tiene, authors of the collection "Sport and cardiovascular diseases”, are seriously concerned about the problem of adequate interpretation and timely diagnosis of heart disease using ECG. There are many examples in this book where misdiagnosis by unqualified physicians of the consequences of injuries contributed to the misinterpretation of ECG results, which, in turn, then harmed the health of athletes.
To know everything, you need to behave correctly
As the doctor of the highest category Zakir Anvarovich Khannanov confirms, an ECG is prescribed by a doctor if the patient himself complains of pain in the heart or problems at work of cardio-vascular system were identified as a result of medical examination. So that the electrocardiogram does not “fail” and, as a result, does not harm the patient himself, before the ECG, doctors do not advise excessive physical exertion of the body: the heart before the examination should work as usual, without extreme sports.
According to the therapist Z. A. Khannanov, the “harm” from the ECG lies, first of all, in the incorrect preparation of the patient for this procedure. Before passing the electrocardiogram, you can not smoke, drink coffee or strong tea (caffeine in any case will affect the results of the examination). It is advisable to eat nothing for 2 hours before the ECG. It is better not to use oil-fat creams applied to the body after a shower before taking an electrocardiogram: the electrodes are difficult to contact with “oiled” skin, which makes it difficult to obtain an ECG.
From Vitalik Buterin, titled "A Guide to Consensus with 99 Percent Fault Tolerance" gives a simplified description of the design and implementation of an algorithm for blockchains that is resistant to inexplicable errors, which in turn is based on a simpler version of Leslie Lamport's algorithm, proposed in 1982 to solve tasks of the Byzantine generals.
The algorithm discussed by Buterin in this paper does not involve giving up proof of work (PoW) or proof of ownership (PoS). However, it should be noted that with some modification of it, such a replacement is possible, especially if decentralization is not so important. The algorithm can be seen primarily as a way to track the creation of blocks for a 51% attack in real time, as well as a method of organizing soft forks to eliminate the consequences of such attacks. The model assumes that if a 51% attack occurs, the possibility of its detection will remain even if the number of legitimate nodes drops to 1%.
Although 51% attacks on Ethereum and other decentralized networks are unlikely, this algorithm can be very useful. There is always a risk of centralization of Ethereum mining pools, and the algorithm will help protect against this threat and increase the trust in the network, attracting more developers, companies and consumers. In addition, the upcoming transition of Ethereum to PoS should reduce fault tolerance by 30-33%, and the above consensus mechanisms will only be able to function if two-thirds of the active nodes are respectable. Thus, the benefit of additional protection against attacks becomes more and more obvious.
It is also important that this algorithm is applicable not only to the ethereum. It can be used by any blockchain projects, including more centralized ones, in which consumers may show significant interest.
Regular Reddit user drcode (this is Konrad Barsky, CEO of Forward Blockchain) explains the above consensus mechanism as follows:
Usually all blockchain problems are related to verification systems (essentially miners). Vitalik proposes that an independent observer of network traffic - the current user of the blockchain (but not a miner or verification system) - monitor what is happening in real time, paying attention to the potential "dirty game" of miners with their 51% attack intentions. This may provide additional security assurances.
Buterin writes about the usefulness of the algorithm, apparently agreeing with drcode's opinion that "understanding such an algorithm goes beyond the technical comfort zone."
[The algorithm] can be used as a tool to detect 51% attacks and to coordinate the prevention of minority soft forks, which also does not require human intervention in extreme situations.
So how does it work in in practical terms? Of course, it all comes down to a complex mathematical equation, but you can figure it out without delving into such details.
At the most basic level, nodes operate on an algorithm that uses hash data and blockchain timeouts to prove the legitimacy of blocks. Thus, observer nodes can track blocks in real time in order to notice the appearance of a "dirty game" from the side of the miners in time. Such a mechanism ensures that if one respectable node sees a “allowable value”, then all respectable nodes, both mining and observing, will see it. It should be said that this mechanism is tied to a time delay, and 99% fault tolerance is guaranteed only when the algorithm is synchronized with block verification.
Of course, algorithms such as Casper, PBFT, Miguel Castro and Barbara Liskov, and similar consensus mechanisms may not finalize blocks all the time, but only if a given number of blocks have already been created. That is, the algorithm cannot be executed after each block, as is required to ensure 99% fault tolerance. In the paper, Buterin also lays out ways to modify an algorithm that is resistant to unexplained errors to 99 percent fault tolerance, but notes that in practice, critical dependency levels are likely to reduce this fault tolerance to about 95 percent.
The modification of the algorithm requires that some observer nodes are always online, watching the finalization of the block formation. At the same time, according to Buterin, 512 randomly selected "finalizing" nodes must execute a given algorithm every 4096 seconds and broadcast data about finished blocks for other nodes, including observer nodes.
Finally, Buterin also talks about the limitations of the proposed algorithm, emphasizing that they are inevitable in any algorithm that is resistant to unexplained errors.
So, it is important to understand: if such an algorithm is implemented, all transactions recorded in the blockchain will be valid and safe if 1% of block producers are respectable and there is a network of observing nodes.
Hello Katherine.
As a rule, the first manifestations of pregnancy can be noticed no earlier than a week after the conception occurred. However, a woman may not always know the exact date of conception, since conception does not always coincide with the time when sperm enters the woman's body. The fact is that spermatozoa can retain their viability in the female genital tract for a short period of time. If ovulation occurs later than the time of intercourse, then it is likely that pregnancy will occur later.
However, pregnancy does not occur in all cases, and a woman who wants to become pregnant tries to pass off any changes in the state of the body as the first signs of pregnancy.
In the body of a woman after conception, changes begin to occur, designed to prepare the body for pregnancy, childbirth, and feeding. As a rule, they begin to occur after the pregnancy has passed the implantation period, that is, there has been an attachment of a fertilized egg in the uterine cavity to its wall. However, not all women feel any change, as sometimes many do not realize that they are pregnant until the day when the next menstruation should begin.
There are cases when a woman, not being pregnant, observes manifestations of pregnancy in herself. This may indicate the presence of other diseases, or the development of such a condition as a false pregnancy.
During the implantation period of pregnancy, short-term pulling pains in the lower abdomen, minor bloody issues lasting, as a rule, no more than one or two days.
In some women, the first signs of pregnancy may appear even before the start of a delay in menstruation, however, they cannot be called objective signs of pregnancy, since these manifestations may also indicate other disorders in the body.
Sometimes in the first week after conception, there may be a general malaise with a slight increase in body temperature, while the rectal temperature after conception always remains elevated.
During pregnancy, there may be a slight increase in vaginal secretions, a slight feeling of heaviness in the lower abdomen and in bladder, although, in most cases, such manifestations are observed on more later dates pregnancy, and sometimes women may experience a change in the sensitivity of the mammary glands
With the onset of pregnancy, a woman may begin to experience bouts of vomiting, diarrhea may appear, sometimes there is a change in taste preferences, headaches, dizziness may be observed.
However, such signs do not always indicate that pregnancy has occurred.
To more accurately say whether pregnancy has occurred or not, an analysis to determine the level of hCG will help, however, a blood test for hCG can be carried out no earlier than twelve days from the time of the intended conception, and a test for determining hCG in the urine should be done only from the first day of missed menstruation.
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5 928 Life exists on Earth only because of a delicate and incredible balance. Our atmosphere, proximity to the Sun and many other beautiful coincidences not only allow living beings to survive and develop, but also to thrive. And yet, we are here, sitting at tables, in cafes and walking along the street, as if it were not some extraordinary miracle. But all good things come to an end. One day the Earth will be inhospitable to anything resembling life as we know it. Life on this planet will probably not stop for billions of years. But, depending on the vicissitudes of astrophysics, it could happen tomorrow or any other time. Here are a few ways scientists say the Earth could die. The earth is surrounded by a protective magnetic shield called the magnetosphere. The field is generated by the Earth's rotation, which spins a thick shell of liquid iron and nickel (outer core) around a solid ball of metal (inner core), creating a giant electrical dynamo. The magnetosphere deflects energy particles that emanate from the Sun, changing its size and shape. The resulting high-energy particle stream that crashes into the Earth's air can cause beautiful auroras or sometimes destructive geomagnetic storms. But if the core cools, we will lose our magnetosphere, as well as our protection from solar winds, which will slowly blow our atmosphere into space. Once rich in water and a thick atmosphere, suffered that same fate billions of years ago, resulting in the nearly airless, seemingly lifeless world we know today. The sun and our position in relation to it is perhaps the most important part of our precarious existence. But the Sun is still a star. And the stars are dying. It is now halfway through its life, steadily converting hydrogen into helium. However, this will not continue forever. Billions of years later, the sun will run out of hydrogen and start burning helium. This reaction will push the layers of the Sun outward and possibly start pulling the Earth towards the Sun. The earth will burn and then evaporate. The expansion of the Sun will push the Earth out of its orbit. It will die like a rogue planet, unattached to any star and drifting through the void. If we talk about rogue planets, then these are worlds that are knocked out of their solar systems during formation. According to recent simulations, in fact, ghost planets can outnumber stars by 100,000 to one. One of these rogue planets could drift into and destabilize the Earth into an extreme and unfavorable orbit. A world big enough and close enough can even push us completely out of solar system. Or make us collide with a nearby planet like Venus or Mercury. As a rogue planet, Earth will become ice ball. And a significant gravitational push could also lead to extreme and deadly times that alternate between very cold and very hot. Or instead of just passing through and destroying Earth's orbit, a drifting world could make a direct hit. It would be unprecedented. About 4.5 billion years ago, a small planet crashed into a large planet in the solar system - forming the Earth and. A new collision will similarly send debris flying through the entire solar system and melt the Earth by 100%. And while the new planet will eventually reform and cool, it remains to be seen if it will be habitable. Asteroids from space can be quite destructive, as big as the one that probably wiped out the dinosaurs, although it would take a lot of asteroids to destroy an entire planet. This is one of Hollywood's favorite apocalypse themes. However, it can happen. The Earth was heavily bombarded by asteroids for hundreds of millions of years after its formation. The impact was so intense that the oceans boiled for a whole year. At this point, all life was single-celled, and only the most heat-tolerant microbes survived. Today's lifeforms almost certainly won't. Temperatures could reach over 900 degrees Fahrenheit for weeks if we were to suffer such a beating. Black holes may be Hollywood's second favorite form of death. It's not hard to guess why. They are as mysterious as they are frightening. Even their name sounds ominous. We don't know much about them yet, but we do know that they are so dense that even light cannot escape the event horizon. And scientists think that "discarded" black holes are roaming the cosmos, just like rogue planets. Incredibly, one of these holes could pass through our solar system. A small black hole can pass the Earth harmlessly, but anything larger than the mass of the moon will cause big problems. If light can't escape, Earth definitely can't. There are two ideas about what might happen after the point of no return, given a sufficiently large black hole. Beyond the event horizon, atoms can stretch until they are completely torn apart. Other physicists suggest that we will go straight to the end or end up in a completely different one. Even if a rogue Black Hole does not affect the Earth itself, it could pass close enough to cause earthquakes and other destruction, knock us out of the solar system, or send us into the sun. Gamma ray bursts (GRBs) are one of the most powerful phenomena in the universe. Most of them are the result of the destruction of massive stars when they die. One short burst can emit more energy than our Sun in its entire lifetime. This energy could eradicate the ozone layer, flood the Earth with dangerous ultraviolet light, and cause rapid global cooling. In fact, a gamma-ray burst could have been the cause of the first mass extinction on Earth 440 million years ago. Luckily, David Thompson, deputy project director at the Fermi Gamma Ray Space Telescope, told National Geographic that GRBs aren't much of a problem. He said the risk was equivalent to "the danger I might face if I found a polar bear in my closet in Bowie, Maryland." This is something that can actually end the entire universe, not just. A mysterious force called dark energy is accelerating and accelerating the universe. If it accelerates, as it is currently doing, perhaps in 22 billion years the force that holds atoms together will fail - and all matter in the universe will dissolve into radiation. Perhaps some microbes will survive to revive a more complex life. But if our destruction is absolute, we can at least hope that there are other universes out there and some other sentient being somewhere.1. Our planet could die if the core of the Earth cools.
2. The sun may start to die and expand
3. Earth could be in a deadly orbit
4. A rogue planet could strike Earth
5. Asteroids can bombard the planet
6. A rogue black hole could approach Earth
7 The Earth's Atmosphere Could Be Destroyed In A Gamma Ray Burst
8 The Universe Might Rip Into Its Final Big Rip
Surgical contraception (sterilization) is one of the most common methods of contraception in the world. According to statistics in Canada, the Netherlands, the UK and New Zealand, 18% of men have undergone a vasectomy, and a quarter of them are married. This surgery is most popular among men aged 40-49.
Vasectomy is not castration. The only common consequence of both procedures is infertility. In 99% of cases, with unprotected contact, pregnancy does not occur. A few months after the operation, you need to continue to protect yourself, since there is a possibility that spermatozoa remained in the seminal ducts.
In some cases, vasectomy may be reversible. If you perform an operation to restore the patency of the seminal ducts (vasovasostomy) in the 10-year period after the previous intervention, then the chances of becoming a father reach 55%. After 10 years, the likelihood of this is greatly reduced. In addition, after sterilization, the number of spermatozoa and their mobility decreases. The seminal fluid itself can also acquire unwanted changes, and even a successful reconstructive operation does not guarantee fertility. [S-BLOCK]
Actor George Clooney had a vasectomy in 1997, and in 2014 he underwent a reconstruction operation. She was successful: despite the long period of time between two surgical interventions, Clooney was able to become a father.
In 2014, the world was shocked by the results of a study by Harvard scientists who concluded that sterilization increases the risk of cancer. prostate. In 2017, the work of scientists from the American Cancer Society was published, in which this hypothesis was refuted.
For several decades, American scientists have been analyzing data from 364,000 men who were about 40 years old at the time the study began in 1982. Vasectomy was performed by 42,000 of them. Over 30 years, 7,400 people died out of the total number. It turned out that the indicators oncological diseases those who underwent sterilization and those who did not do this operation do not differ. But whether the men smoked and whether they had excess weight influenced the development of tumors. Does not cause sterilization and testicular cancer. [S-BLOCK]
In the 1980s, several studies came out that showed evidence that libido may decrease after surgery.
Now, most urologists believe that the libido of those who have had a vasectomy remains at the same level. A man still produces hormones, he has a normal erection, even the amount and appearance ejaculate remains unchanged - the only difference is that there are no more spermatozoa in the ejaculate.
Psychologists believe that there may even be an increase in intimate activity, because the fear of unwanted partner pregnancy disappears. A man is liberated - he no longer needs to think about possible failures of contraception.
Women also begin to trust a man more, to perceive him as "sharing" the traditional concerns about contraception, which are attentive to family planning. The operation is often performed by men who already have children. In addition, male sterilization is easier to carry out than female. [S-BLOCK]
Approximately 90% of men who have had a vasectomy are satisfied with the result. Some, however, experience depression and impotence, but these problems are psychological in nature and are treated therapeutically.
The operation itself takes about half an hour and is performed through small incisions or in a minimally invasive way - through a puncture in the scrotum. The surgeon separates the ends of the ducts and “solders” them with a laser.
Sometimes after the procedure, it is necessary to apply cooling compresses for some time, and painful sensations are noted, which soon pass. There is also the so-called post-vasectomy pain syndrome in Western practice. It can develop even several years after surgery and be chronic. This is pain that is constant or occurs during ejaculation, physical exertion. In rare cases, as with any surgical intervention, there may be undesirable consequences: hematomas (hemorrhages), postoperative infections.
Vasectomy works well in couples when the partners are healthy and faithful to each other because it does not protect against sexually transmitted diseases. So even after sterilization, it is better for Casanovas to continue using condoms and get tested regularly.
