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» Glavni naslovi






Everywhere on gas

Due to the increasing pollution of the environment and its consequences for nature and human health, also the substances people use today are required not to pollute the environment. Among them are fuels, substances that during oxidation (usually with oxygen from the air) during combustion or combustion have a series of chemical reactions in which, due to changes in chemical components, heat and combustion products are created. Different fuels and their combustion products affect the environment in different ways, which is determined only after a thorough examination of their toxicity, e.g. natural gas during combustion provides thermal energy that is used for heating apartments and businesses, as well as in power plants for electricity production. It is cost-effective because it is an easily accessible resource, and it is a cleaner alternative to coal. However, the combustion of this gas, as a waste product, in addition to water vapor, also produces carbon dioxide (CO2), which is often said to be "the most important greenhouse gas produced by man."
One of the possible alternatives to natural gas is hydrogen (H), which releases heat during combustion, and the only waste product is water vapor. Because it does not emit CO2 during combustion, the use of hydrogen for energy brings numerous environmental and social benefits. However, the problem is that hydrogen on Earth cannot be found in its pure form. It must be produced, ie energy must be invested to obtain the desired fuel, so when using hydrogen, the method of its production is taken into account.



Surgical therapy of thyroid diseases

Eminent expert in endocrine surgery, ass. dr sci. med. Marko Buta, a consultant at Belgrade's Bel Medic General Hospital, says that thyroid cancers are generally considered diseases with a very good prognosis, and with an extraordinary chance of survival. Thanks to modern endocrine surgery, the majority of patients who have undergone surgery for thyroid cancer return to normal life as healthy people. With appropriate hormone replacement therapy, they continue to live quite normally, although surgical treatment of cancer usually requires that the thyroid be removed completely. Ass. dr sci. med. Marko Buta, a specialist in general and subspecialist in oncological endocrine surgery, says that malignant thyroid tumors today generally have a very good prognosis, provided that they are operated on, following the guidelines of European and world guides. Although these are very delicate operations that can potentially have serious complications, Dr. Buta adds that good surgical skills, new medical devices used in general and endocrine surgery, and especially the neuromonitoring device - voice nerve identification, provide almost 100% success in the surgical treatment of thyroid disease. Moreover, the thyroid gland is removed preventively in children with a genetic predisposition to medullary thyroid cancer.



Searching through the legacy of genius

It took half a century from the death of Nikola Tesla to begin studious research of his patent writings and determine the final list of all patents he applied for in 26 countries around the world. What remained shrouded in secrecy even after the completion of that great and important work were the discoveries that Tesla failed to protect for various reasons. Only fifteen years later, thanks to a careful analysis of extensive material from Tesla's archive kept in the Nikola Tesla Museum in Belgrade, detailed insight into this hitherto unknown part of the work of the genius scientist, engineer, and inventor was published.
Although numerous newspaper articles and texts about Nikola Tesla have been published in scientific and professional publications, as well as countless books on various aspects of the life and work of the great scientist and inventor, and numerous interviews with Tesla in various periods of his life, very few publications have been dedicated to his patents, thus to the very essence of his contribution to the emergence of the second industrial revolution and the overall world technological development.



Geological treasure preserved from man

The Geological and Paleontological Collection is a closed museum within the Faculty of Mining and Geology of the University of Belgrade and consists of the collections of the Department of Regional Geology and the Department of Palaeontology. It was formed in 1889, to improve teaching and for students to acquire as much practical knowledge as possible.
The basis of the collection, as well as the Collection of Minerals and Rocks of that faculty, is the material donated by the mining engineer Baron Herder, invited in 1835 to Serbia by Prince Miloš Obrenović to explore its mineral wealth and encourage the development of mining. The development of geology in Serbia began with the production of geological maps, and for that work, it was necessary to determine the age of the rocks, thus the development of paleontology.
The paleontological collection serves to preserve the basic part of someone's field research, to check tomorrow what kind of research has been done in the past. The collection consists of over twenty thousand samples that were collected during previous research and testify to the geological history of Serbia.



Golden indigenous apple

At the beginning of 2020, one important scientific work was published: the monograph "Indigenous apple varieties in Serbia and Montenegro" by Dr. Evica Mratinić, professor at the Faculty of Agriculture, University of Belgrade. This book, which is a kind of "gene bank" and "knowledge bank" for current and future generations of her colleagues who are engaged in breeding, has now received the first media attention. It is the result of the professor's thirty years of work with associates in the field and the laboratory.
The book deals with more than 350 indigenous apple varieties (each adapted to specific soil and climate). It presents 17 areas where they are grown, and which are connected with administrative municipalities in Serbia. Montenegro has practically only one region that is important for the cultivation of continental fruits (the Bijelo Polje area).
Considering that some of those apples also appear on the coast, another region in Montenegro has been added - the so-called coastal region.



Beavers "forced" to divorce

Mating in animals in areas with temperate or cold climates, as a rule, has a seasonal frequency. During this period, many vertebrates acquire secondary sexual characteristics (for example, they change color and get into a "wedding spirit" before mating, which is the case with some fish and birds). The beginning of the mating season is regulated by the seasonal activity of the gonads, which produce hormones that stimulate the sexual activity of animals. In the tropics, animals do not breed strictly periodically, but even there, the onset of mating is often timed to coincide with the rainy season.
Courtship is the act by which a male performs physical rituals in front of a female, intending to show that he is capable of mating with her. The female, who has an instinct, analyzes the characteristics of each male. She must choose the one who is the strongest and who can produce good offspring. These rituals can take the form of dances, shouts, songs, or aggressive fights with other males. The female will eventually mate only with the best of its kind.



Maybe it's not an asteroid but ...

The asteroid Ryugu has a diameter of about 980 m and belongs to the asteroid group type C (high carbon content). In 2014, the Japanese space agency launched the Hayabusa 2 spacecraft towards the asteroid, which arrived at its destination in June 2018 and orbited it for more than a year. During that part of the mission, four rovers were sent to the surface of the asteroid. After the completion of the task, a sample of this space body was delivered to our panel, in December 2020.
The "Hayabusa 2" mission discovered that Ryugu was composed of numerous remains. It is not a single piece of rock but a set of smaller rocks. It is pointed and has a fast rotation. Experts believe that Ryugu was formed after the collision of larger asteroids and later by gravity-accumulated debris. Although the thesis that Ryugu is an asteroid is still emphasized, one detail does not support this assumption: namely, does Ryugu have a high concentration of organic matter? The issue was discussed in a study published in the Astronomical Journal Letters, entitled "Asteroid 162173 Rjugu: The Origin of a Comet." The authors state that Ryugu could be the remnant of a comet.



Logic and philosophy of numbers

Mathematics has been studied at the Faculty of Philosophy of the Great School in Belgrade since 1905. And when the Faculty of Natural Sciences and Mathematics was founded in 1947, mathematics studies became part of academic teaching. In the 1977/78 school year was introduced subject: the philosophy of mathematics. In short, it is a branch of philosophy that studies the assumptions, foundations, and implications of mathematics. Its goal is to understand the nature and methods of mathematics because the logical structure and nature of mathematics give philosophy a new dimension. The directions of the philosophy of mathematics are Platonism, formalism, logicism, cognitive theories, and social constructivism.
The logical cause-and-effect structure of mathematics is perfect. But is that always the case? First, the hitherto unimaginable denial comes from geometry. Euclid described the space in which we move with geometry that is completely in line with experience. Logically built, his system stood firmly in the general system of human knowledge, so many great scientists throughout history have sworn by it.
In 1826, Nikolai Ivanovich Lobachevsky exhibited, at the University of Kazan (Russia), the results of his research on a new geometry that had no experiential confirmation. That geometry brought a revolution in science, showing that Euclidean geometry is only one of the alternative geometries.




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