In this review, a hypothesis is proposed to explain the beneficial effect of an enriched environment (EE) on the conditioned fear reaction (CFR) from the perspective of a functional system of ...behavioral control. According to the hypothesis, the EE affects all behavioral act components, including the processing of sensory information, memory, motivational and reinforcing systems, and motor activities, which weakens the CFR. Animals raised in the EE have effects that are comparable to those of context (CTX) and CS pre-exposures at latent inhibition. An abundance of stimuli in the EE and constant contact with them provide the formation of CS-noUS and CTX-noUS connections that later, during CFR learning, slow down and diminish fear. The EE also contributes to faster processing of information and habituation to it. As a result, many stimuli in the context lose their significance, and subjects simply ignore them. And finally, the EE affects the motivational and reinforcing brain mechanisms, induces an impairment of search activity, and worsens memory consolidation, which leads to a reduction of CFR.
Many in the West, especially in the human rights community, saw the end of the Cold War as a great opportunity for a normative transformation in international relations. They argued that the concept ...of sovereignty was an anachronism and that a new international regime should be created allowing for easier intervention against states that subject their citizens to violence. It seemed like a relatively straightforward issue of clashing normative principles at fi rst. As the conversation about interventions has evolved, however, it has become increasingly clear that the problem is much more complex. This article examines the set of complex trade-off s between various values and norms related to humanitarian intervention and demonstrates that no interventionist doctrine that balances these values and norms is possible. It empirically examines these tensions in the context of interventions in Kosovo and Libya.
The article focuses on the current problem – the efficiency of employees' working hours through the use of special systems for work time planning (workforce management). An analysis of the use of ...various management tools to create an effective employee schedule is presented. It has been shown that the number of companies implementing automated programs for recording and planning employees' working hours is gradually growing. The main advantages and disadvantages identified by managers implementing digital solutions in the work schedule process were identified. Various types of specialized software for creating a flexible work schedule have been investigated, as well as key criteria by which the best WFM systems are determined. In the course of this classification, parameters have been defined, which should be given special attention when deciding on the use of the WFM system in the company. Based on the results of the study conducted by the author, recommendations were developed for the implementation of such digital solutions in the company. The author concluded that these systems were necessary for enterprises focused on digitalizing their business, since they made it possible to optimize staff costs and increase employee efficiency.
We derive 15 classes of time-dependent two-state models solvable in terms of the confluent Heun functions. These classes extend over all the known families of three- and two-parametric models ...solvable in terms of the hypergeometric and the confluent hypergeometric functions to more general four-parametric classes involving three-parametric detuning modulation functions. In the case of constant detuning, the field configurations describe excitations of two-state quantum systems by symmetric or asymmetric pulses of controllable width and edge-steepness. The classes that provide constant detuning pulses of finite area are identified and the factors controlling the corresponding pulse shapes are discussed. The positions and the heights of the peaks are mostly defined by two of the three parameters of the detuning modulation function, while the pulse width is mainly controlled by the third one, the constant term. The classes suggest numerous symmetric and asymmetric chirped pulses and a variety of models with two crossings of the frequency resonance. We discuss the excitation of a two-level atom by a pulse of Lorentzian shape with a detuning providing one or two crossings of the resonance. We derive closed form solutions for particular curves in the 3D space of the involved parameters which compose the complete return spectrum of the considered two-state quantum system.
For a massive quantum fermionic field, we investigate the vacuum expectation values (VEVs) of the charge and current densities induced by an external magnetic flux in a two-dimensional circular ring. ...Both the irreducible representations of the Clifford algebra are considered. On the ring edges the bag (infinite mass) boundary conditions are imposed for the field operator. This leads to the Casimir type effect on the vacuum characteristics. The radial current vanishes. The charge and the azimuthal current are decomposed into the boundary-free and boundary-induced contributions. Both these contributions are odd periodic functions of the magnetic flux with the period equal to the flux quantum. An important feature that distinguishes the VEVs of the charge and current densities from the VEV of the energy density is their finiteness on the ring edges. The current density is equal to the charge density for the outer edge and has the opposite sign on the inner edge. The VEVs are peaked near the inner edge and, as functions of the field mass, exhibit quite different features for two inequivalent representations of the Clifford algebra. We show that, unlike the VEVs in the boundary-free geometry, the vacuum charge and the current in the ring are continuous functions of the magnetic flux and vanish for half-odd integer values of the flux in units of the flux quantum. Combining the results for two irreducible representations, we also investigate the induced charge and current in parity and time-reversal symmetric models. The corresponding results are applied to graphene rings with the electronic subsystem described in terms of the effective Dirac theory with the energy gap. If the energy gaps for two valleys of the graphene hexagonal lattice are the same, the charge densities corresponding to the separate valleys cancel each other, whereas the azimuthal current is doubled.
This review describes the role of social isolation in the development of anxiety and depression-like behavior in rodents. The duration of social isolation, age from onset of social isolation, sex, ...species, and strain of animals, the nature of the model used, and other factors have been shown to have influences. The molecular-cellular mechanisms of development of anxiety and depression-like behavior under the influence of social isolation and the roles of the HHAS, oxidative and nitrosative stress, neuroinflammation, BDNF, neurogenesis, synaptic plasticity, as well as monoamines in these mechanisms are discussed. This review presents data on sex differences in the effects of social isolation, along with the effects of interactions with other types of stress, and the roles of an enriched environment and other factors in ameliorating the negative sequelae of social isolation.
Noise is considered one of the environmental hazards that negatively affect health. It can cause damage to the auditory, neurological, hormonal and cardiovascular systems, in addition to impairing ...psychological and cognitive functions. Considering the significance of vascular disturbances and oxidative stress in the development of the aforementioned negative effects, the purpose of our investigation was to study the level of high density lipoprotein-cholesterol (HDL-Cl), low density lipoprotein-cholesterol (LDL-Cl), and total cholesterol (TCl) in plasma, in addition to the behavioral characteristics of white rats, and the effects of the α2-adrenoblockers beditin and mesedin to reveal their antiatherogenic effect during noise exposure. The “Open field” and “Y-maze” tests were used in order to evaluate the behavioral states of the rats. Investigations were carried out on albino rats divided into 4 groups. The 1st group of rats served as a control. The 2nd, 3rd and 4th groups were exposed to 91 dBA of noise; the duration of exposure was 8 h per day for 60 days. The 3rd group was injected with beditin and the 4th group with mesedin, both intraperitoneally and repeatedly. According to our results, the chronic exposure to high-volume noise leads to the increase of plasma TCl and LDL-Cl concentrations and the decrease of HDL-Cl levels, resulting in increase of the atherogenic coefficient, which is estimated to be one of the main cardiovascular disease risk factors. The “Open field” and “Y-maze” tests revealed that chronic noise exposure caused disturbances in the behavioral activity, a noise duration-dependent delay in movement and orientation, increased anxiety and deficit in the animals’ spatial memory. The administration of α2-adrenoblockers to the noise-exposed animals had a regulatoryeffects of varying intensities, depending on the medication used and the studied parameters under the conditions of chronic acoustic stress.
Display omitted
•The chronic noise impact increased amount of LDL-Cl and decreased amount of HDL-Cl.•Noise increases the risk of cardiovascular diseases and atherosclerosis.•The cognitive disorder in noise impact is represented by the increased anxiety.•Noise brought to a duration- dependent deficit of memory of experimental animals.•On the noise impact background, the α2-adrenoblockers had a regulatory effect.
In the present work, the exact solutions for two problems of the antiplane stress state of a uniformly piecewise homogeneous space formed by alternately joining two heterogeneous layers of equal ...thickness from different materials, which is weakened on the junction planes of layers by a periodic system of parallel semi-infinite tunnel cracks are obtained. In the first of these problems, it is assumed that stresses are given on the crack banks, and in the second problem, that stresses are given on one of the crack banks and displacements on the other.
PDF
