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» Glavni naslovi





The great inventions of humanity

In its long history, from the distant past to the present, people have sought to improve their lives and facilitate their daily existence - through work and imagination, learning and daydreaming, applying experiences, and sometimes by chance or by force of necessity. The number of inventions increased, improved, and everyday life became easier and more meaningful. A lever, a wheel, a printing press, gunpowder, a compass, a laser, a paper and a pen, solar panels, a transformer, a photograph, a light bulb, a steam engine, an airplane ... in moments of special inspiration and after many thought and checking, it occurred to someone and - all the necessary inventions were created. One shortcut to humanity's development has been opened. And so on, to this day. Even today, Mankind hurries forward. Some of these inventions resemble something that we left behind long ago and say we should not turn our heads too much. Still, is that right?



Deep learning and shallow understanding

The revolution of modern artificial intelligence is, in fact, a counter-revolution. Moreover, her first win was in the realm of language. In 1976, Drew McDermott, a researcher at the Massachusetts Institute of Technology, published a paper in which he described and criticized one weakness that scientists in the field of artificial intelligence are vulnerable to.Assigning a sound name to some software functionality creates the illusion - even with the software author himself, or especially with him - that the observed functionality is really, what its name implies. McDermott rightly observed that this kind of "disorderly thinking" is being disrupted for scientific discipline.The title of the publication was indicative: "Artificial intelligence meets natural stupidity." Time has shown that the region has evolved precisely to the death that McDermott warned about.



Insulin resistance and nutrition

Insulin resistance is a form of pre-diabetes - an almost asymptomatic condition that often does not alert you to the risk of diabetes. Talking about this disorder of sugar metabolism, TijanaDangubic, MD, PhD, Bel Medic endocrinologist, points out that insulin resistance is very successfully corrected if lifestyle changes. It is well known that one of the most common chronic non-communicable diseases, type 2 diabetes (diabetes mellitus), is a global health problem, primarily because it can have very serious consequences: it is the main cause of blindness, kidney failure, heart attacks and possible strokes and lower limb amputation ..But there is little talk that diabetes does not occur suddenly but is preceded by a pre-diabetes condition during which adverse development can be almost completely reversed, by changing lifestyle and above all - diet. The problem is that pre-diabetes is mostly not "alarming", has no symptoms or these are symptoms that are hidden, so almost 90 percent of patients are unaware that they are on the verge of serious chronic diseases.



Risks to Earth's Sheath

Rocket engines do not use atmospheric oxygen, so they can be used in a vacuum to propel ballistic missiles and spacecraft. Rocket motors most commonly use chemical rocket fuels which, when combusted in a combustion chamber, produce high temperatures and high-pressure gases (10-200 bar). These gases, when leaked through a profiled jet, reach supersonic velocity, thus generating a reaction force (thrust) directed in the opposite direction to the gas leak direction. Chemical rocket fuel consists of solid or liquid fuels and oxidizers. Solid rocket fuel is a mixture of solid fuel and a solid oxidizer, which is placed in a suitable housing to be used simultaneously as a combustion chamber. Liquid rocket fuel consists of liquid fuel matter and liquid oxidizer, which are placed in separate tanks, from which they are pumped into injectors through which, under pressure, they are injected into the combustion chamber, where they are mixed and combined combusted. Hybrid rocket motors use a combination of solid and liquid or gaseous fuels and oxidizers... Moreover, it is all moving and falling on the ground of our planet.



Cosmic probes of the future

Exploring the solar system with space probes has, over the six decades of its development, become the most successful astronautics field since the launch of the first "moons"; Thanks to the data transmitted by probes, this field represents a continuous scientific revolution and is constantly expanding our knowledge of our closer cosmic neighborhood. The experiences of previous probation missions and new science and technology capabilities have formed the basis for designing more complex future probes, with more ambitious exploration programs for the worlds that they are to be launched towards. The design, manufacture and preparation of a space probe is a process that takes several years, although it generally takes over a decade. Probes are now being designed that will begin their missions only in the middle of the next decade, and breaking the set of deadlines for completion and launching due to unforeseen problems has become a normal occurrence in astronautics. The application of new technical solutions in order to realize the unfulfilled ventures so far almost regularly leads to consideration of problems that were not observed before the start of the realization. Sometimes, these problems lead to a project change or even delay for some future time. What are cosmos researchers preparing today?



The influence of the Moon on Earth

Ever since he first saw the Moon, man was fascinated by its radiance and appearance. Since the creation of civilization, humans have known that this celestial body has a powerful influence on them, but also on plants, animals, the sea and weather. There are many stories and legends that still intrigue the imagination? The Moon was created 4.5 billion years ago. It is 384,400 km away from Earth. Moon movement involves four lunations. The Synodic month lasts 29.5 days with the minimum active youth and maximum full moon activity. The lunar cycle gives rise to a phenomenon that the living world can recognize, including changes in light intensity, geomagnetism and gravity. The most famous moon influence on some changes on the Earth's surface is an example of tides, while less is known about its effect on plant growth and fertility. In fact, this knowledge has existed almost always, but it has only been transmitted as people's beliefs and experiences, not finding a place in the exact science.



After Space, Chernobyl and Fukushima

The term radiation means the emission of radiation or particles from some sources. Very high-energy radiation, which directly or indirectly produces ions, is ionizing radiation. Ionizing radiation is the main cause of "injury" to protoplasm that occurs in the material that absorbs them. These radiations occur in nuclear reactions and processes, such as special laboratory and industrial devices, and also are present in cosmic radiation. Radioactivity is the ability of some chemical elements, ie matter, to emit invisible particles or rays of high energy. Isotopes of elements that emit ionizing radiation are radioisotopes or radionuclides. The sources of ionizing radiation are alpha particles, large, positively charged particles, beta particles, finer, negatively charged particles and gamma rays, neutral electromagnetic waves of very small wavelengths. Physicists have calculated that gamma-ray shocks, caused by large explosions in space, may have prevented the development of life in much of the galaxy. Intense radiation is lethal to even the most durable known life forms, and can remove important gases from the atmosphere. According to recent measurements, most of the Milky Way is not suitable for life precisely because of gamma rays.



Ancient sharks around Belgrade

Sharks have existed for hundreds of millions of years, and have been recorded in fossil lists before many other groups were found. But the questions: how they evolved, whether they can be considered "living fossils", why their teeth are such a common occurrence in many rocks around the world, or how they survived mass extinctions ... there are still no complete answers. These dangerous sea monsters cruised the waters of former oceans and seas such as Tethys, Paratetis, the Mediterranean Sea, etc. In search of prey, they also took refuge in the shallow-water coastal areas that existed in the Middle Miocene in Serbia and the surrounding regions (about 14 to 15 million years ago). Until recently, only shark teeth called Megalodon were known. The latest research on teeth found near Visnjica, part of Belgrade, has shown that they belong to a different genus. What species of sharks roamed the sea around Belgrade are revealed by fossils that the author, in collaboration with paleontologists from Romania and the Museum of Natural History in Belgrade, described in the latest issue of the journal "Geological Annals of the Balkan Peninsula".



Temperatures in residential buildings

Energy efficiency and renewable energy sources are two pillars of sustainable energy policy. Both should develop simultaneously in order to stabilize and reduce carbon dioxide emissions. The aim is to reduce the consumption of fossil energy sources and increase energy consumption from renewable sources. Modern home appliances use significantly less energy than the old appliances of the same kind. For example, today's refrigerators use 40% less energy than those produced in 2001. Replacing 10 and more years old householdappliances with modern ones would save 20 billion kWh of energy per year (Serbia produces 34 billion kWh a year). CO2 emissions would be reduced by 18 billion kilos! In fact, replacing obsolete household appliances is the most effective way to reduce the consumption of electricity and the emissions of gases that create the greenhouse effect.


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