Quantum mechanics

Quantum mechanics, including quantum field theory, is a fundamental theory in physics which describes nature at the small – atomic and subatomic – scales. By contrast, classical physics, the description of physics that existed before the formulation of the theory of relativity and of quantum mechanics, describes nature at ordinary scale. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large scale. Quantum mechanics differs from classical physics in that energy, angular momentum, other quantities of a bound system are restricted to discrete values, objects have characteristics of both particles and waves, there are limits to how the value of a physical quantity can be predicted prior to its measurement, given a complete set of initial conditions. Quantum mechanics arose from theories to explain observations which could not be reconciled with classical physics, such as Max Planck's solution in 1900 to the black-body radiation problem, the correspondence between energy and frequency in Albert Einstein's 1905 paper which explained the photoelectric effect.

Early quantum theory was profoundly re-conceived in the mid-1920s by Erwin Schrödinger, Werner Heisenberg, Max Born and others. The modern theory is formulated in various specially developed mathematical formalisms. In one of them, a mathematical function, the wave function, provides information about the probability amplitude of energy and other physical properties of a particle. Scientific inquiry into the wave nature of light began in the 17th and 18th centuries, when scientists such as Robert Hooke, Christiaan Huygens and Leonhard Euler proposed a wave theory of light based on experimental observations. In 1803, English polymath Thomas Young described the famous double-slit experiment; this experiment played a major role in the general acceptance of the wave theory of light. In 1838, Michael Faraday discovered cathode rays; these studies were followed by the 1859 statement of the black-body radiation problem by Gustav Kirchhoff, the 1877 suggestion by Ludwig Boltzmann that the energy states of a physical system can be discrete, the 1900 quantum hypothesis of Max Planck.

Planck's hypothesis that energy is radiated and absorbed in discrete "quanta" matched the observed patterns of black-body radiation. In 1896, Wilhelm Wien empirically determined a distribution law of black-body radiation, called Wien's law. Ludwig Boltzmann independently arrived at this result by considerations of Maxwell's equations. However, it underestimated the radiance at low frequencies; the foundations of quantum mechanics were established during the first half of the 20th century by Max Planck, Niels Bohr, Werner Heisenberg, Louis de Broglie, Arthur Compton, Albert Einstein, Erwin Schrödinger, Max Born, John von Neumann, Paul Dirac, Enrico Fermi, Wolfgang Pauli, Max von Laue, Freeman Dyson, David Hilbert, Wilhelm Wien, Satyendra Nath Bose, Arnold Sommerfeld, others. The Copenhagen interpretation of Niels Bohr became accepted. Max Planck corrected this model using Boltzmann's statistical interpretation of thermodynamics and proposed what is now called Planck's law, which led to the development of quantum mechanics.

After Planck's solution in 1900 to the black-body radiation problem, Albert Einstein offered a quantum-based explanation of the photoelectric effect. Around 1900–1910, the atomic theory but not the corpuscular theory of light first came to be accepted as scientific fact; however the photon theory was not accepted for a until about 1915. Until Einstein's Nobel Prize, Niels Bohr did not believe in the photon. Among the first to study quantum phenomena were Arthur Compton, C. V. Raman, Pieter Zeeman, each of whom has a quantum effect named after him. Robert Andrews Millikan studied the photoelectric effect experimentally, Albert Einstein developed a theory for it. At the same time, Ernest Rutherford experimentally discovered the nuclear model of the atom, Niels Bohr developed a theory of atomic structure, confirmed by the experiments of Henry Moseley. In 1913, Peter Debye extended Bohr's theory by introducing elliptical orbits, a concept introduced by Arnold Sommerfeld; this phase is known as old quantum theory.

According to Planck, each energy element is proportional to its frequency: E = h ν, where h is Planck's constant. Planck cautiously insisted that this was only an aspect of the processes of absorption and emission of radiation and was not the physical reality of the radiation. In fact, he considered his quantum hypothesis a mathematical trick to get the right answer rather than a sizable discovery. However, in 1905 Albert Einstein interpreted Planck's quantum hypothesis realistically and used it to explain the photoelectric effect, in which shining light on certain materials can eject electrons from the material. Einstein won the 1921 Nobel Prize in Physics for this work. Einstein further developed this idea to show that an electromagnetic wave such as light could be described as a particle, with a discrete amount of energy that depends on its frequency. In his paper “On the Quantum Theory of Radiation,” Einstein expanded on the interaction between energy and matter to explain the absorption and emission of energy by atoms.

Although overshadowed at the time by his general theory of

Portrait of Catherine Balebina

Portrait of Catherine Balebina is a painting by Russian portrait artist Lev Russov, which depicts his wife Catherine Balebina. The portrait was painted in Leningrad in 1956 and belonged to the most famous portrait paintings of artist, he met with Catherine Balebina in 1955, one year before. Soon she too become the mother of his son and the main muse. Charming and lively, full of self-sacrifice, it would pose Leo Russov as a model for many paintings and portraits. For many years it will create and preserve a world in which manifested itself in full force and flashed a creative gift by Lev Russov. In the portrait of his wife, Russov raises on a pedestal gamine image of feminine charm. Seems Rusov not pursue any purpose other than to sing this perfect image, and he does it according to the laws of the genre. Author found a neutral background, which in combination with a closed dark blue dress let all the attention focused on her face shaded chestnut mane of hair. At the full force transferred expressive eyes of a young woman.

Her gaze directed to the side, at the corner of her sensual lips hid a smile. As a contrast with the static posture her eyes talk about independent nature. We can read this in general expression of the face of a young woman. In the portrait there are no details belongs to place. And, yet, we do not hesitate to recognize the young woman as a contemporary of the middle - second half of the 1950s. Never early the female images in Russian Art was not as open, cheerful and without a trace of affectation, never carried a combination of the spiritual and physical beauty with deep civic and independent views; until the early 1990s, Portrait of Catherine Balebina was kept in the family of the artist. In the future, he was acquired in a private collection. In 2007 the «Portrait of Catherine Balebina» has been described and reproduced in the book «Unknown Socialist Realism; the Leningrad School» among 350 selected works by artists of the Leningrad School. Portrait of Yevgeny Mravinsky Artist Lev A. Russov Leningrad School of Painting Directory of Members of the Union of Artists of USSR.

Volume 2. Moscow, Soviet artist, 1979. P.290. Directory of members of the Leningrad branch of Union of Artists of Russian Federation. Leningrad, Khudozhnik RSFSR, 1980. P.103. Иванов С. О ранних портретах Льва Русова // Петербургские искусствоведческие тетради. Выпуск 23. СПб. 2012. С.7-15. «Portrait of Catherine Balebina» on VIDEO "Artist Lev Alexandrovich Russov. Masterpieces of Painting of 1950-1970s" Portrait of Catherine Balebina. Lev Russov Solo Exhibition in The Museum of Art

Parent bug

Elasmucha grisea, common name parent bug, is a species of shield bugs or stink bugs belonging to the family Acanthosomatidae. The term parent bugs includes the other species of the genus Elasmucha and some species of the family Acanthosomatidae. Subspecies within Elasmucha grisea include: Elasmucha grisea cypria Josifov, 1971 Elasmucha grisea grisea Elasmucha grisea is a rather common and widespread species present in most of Europe. Elasmucha grisea can reach a length of 6.5–8.8 millimetres. Males are smaller than females; these medium-sized shieldbugs are brown-reddish, but there are gray and green-brown specimen. Connexivum is white; the upperside is covered with several dark dots. The scutellum shows an evident black patch; the ventral face is punctuated with black. Lateral corners of the pronotum are beveled; the front corners of the pronotum show a more pronounced tooth. Antennas are blackish in the dark brown in the female; this species, like other parent bugs possess methatoracic and abdominal glands, which discharge a foul smelling secretion.

This secretion is used to deter potential enemies and is sometimes released when the bug is disturbed. Adults of Elasmucha grisea can be found all year around. In fact this species overwinters as an adult. Mating occurs in the spring and new adults can be found in August; these shield bugs feed on various woody plants, preferably on birch, but on alder, holly, etc. Like most shield bugs, Elasmucha grisea and other parent bugs suck plant sap and require symbiotic bacteria for their digestion, they obtain symbionts at an early age: the mother covers her eggs with bacteria so that the larvae ingest them as they feed on the egg case. Both adults and larvae feed on developing seeds, breeding individuals can be observed on host plants with many young catkins. However, they seem to avoid trees with a high predation risk; the common name of Elasmucha grisea comes from the rare insect behaviour of prolonged caring for eggs and juveniles, exhibited by females of this species. Predators, such as bugs, beetles and ants, can eliminate all the offspring of the parent bug if there is no maternal care.

The repertoire of female defensive behaviours includes wing fanning, body jerking, tilting towards the enemy and releasing of'nasty’ odours from the scent glands,After oviposition, the parent bug female stands over the egg batch and shields it throughout egg development. Predation appears to limit the clutch size in E. grisea. Experiments have shown. However, when the clutch size was manipulated, small females protecting large clutches lost more eggs than large females guarding small clutches or females in the control groups. After hatching, larvae of the parent bug remain in a tight aggregation, feeding on their empty egg shells; when any larva tries to abandon the aggregation, the female tilts her body, stretches her antennae to reach the larva and pushes the larva back to the aggregation. During the second and third instar they move, for food, towards catkins back to the leaf with the female in close attendance; the female keeps a lookout for the larvae and manages them with touches of her antennae.

Larvae form smaller groups and disperse at the end of the third instar, at which point the female leaves them. It has been noted. While some larvae are still at the first instar stage, others have moulted to the stage of second instar larvae and abandon the brood leaf for food. Under such circumstances, the female is no longer able to provide effective protection for all her larvae; the offspring of different females make contact with form mixed groups. There is no kin-recognition in this species. Both single and joint guarding females provide parental care for their own larvae or other females’ offspring. Larvae are to benefit from'kindergartens', when their mothers disappear or die. Moreover, joint-guarding females defend the egg clutches much more than single females; the tachinid fly, Subclytia rotundiventris, is a specialist endoparasite of the parent bug females. The parasite inserts a single egg through the upper prothorax of an E. grisea female and, after hatching, the larva feeds on its host.

At the beginning the parasite feeds only on the non-vital parts of the bug, but it kills it and pupates outside the host. The larva ‘permits’ the parent bug to continue caring for the juveniles until their third stage. In experiments, the wing-fanning did not differ between parasited and non-parasited females until the nymphs were at the second instar stage. However, with older nymphs, females were much less effective in their defensive behaviour and died before the end of maternal care. Considering that the older nymphs are more mobile and may escape from predators, some offspring of the parasited females of the parent bug survive and may be potential hosts for the new generation of the parasite. List of shield bug species of Great Britain "Elasmucha grisea L." Nature spot. Kaitala, Arja. "Experiments with Elasmucha grisea L." Behavioral Ecology. by Johanna Mappes and Arja Kaitala. 5: 314–317. Doi:10.1093/beheco/5.3.314. "Distribution and Taxonomy". A. Ogorzałek, A. Trochimczuk. "Ovary structure in a presocial insect, Elasmucha grisea".

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