62 research outputs found
On the Psychological Mechanism of Ontogenetic Development in the Context of Developmental and Educational Psychology
No full textAbstractThe article offers the author's view of the psychological mechanism for the development of a child. It is regarded as the process of ripening and resolving of fundamental contradictions between the child's system of relations and modes of activity acquired by him. Underlined by the author is the objective nature of ontogenetic development as well as the role of child's motivation as a driver of necessary transformations of the child's activity leading to his psychological growth. The similarities and differences between the author's approach and that of D. B. Elkonin are precisely traced. The author’ arguments are supported by a lot of evidence from the theory and practice of developmental and educational psychology with special focus on the role of social institutions
Tracer diffusion on a crowded random Manhattan lattice
No full textWe study by extensive numerical simulations the dynamics of a hard-core tracer particle (TP) in presence of two competing types of disorder -frozen convection flows on a square random Manhattan lattice and a crowded dynamical environment formed by a lattice gas of mobile hard-core particles. The latter perform lattice random walks, constrained by a single-occupancy condition of each lattice site, and are either insensitive to random flows (model A) or choose the jump directions as dictated by the local directionality of bonds of the random Manhattan lattice (model B). We focus on the TP disorder-averaged mean-squared displacement, (which shows a super-diffusive behaviour ∼t4/3, t being time, in all the cases studied here), on higher moments of the TP displacement, and on the probability distribution of the TP position X along the x-axis. Our analysis evidences that in absence of the lattice gas particles the latter has a Gaussian central part ∼exp(−u2), where u=X/t2/3, and exhibits slower-than-Gaussian tails ∼exp(−|u|4/3) for sufficiently large t and u. Numerical data convincingly demonstrate that in presence of a crowded environment the central Gaussian part and non-Gaussian tails of the distribution persist for both models
Evaluating expectation-maximization algorithm for 2D DOA estimation via planar antenna arrays
No full textCorporate control and governance practices in Russia
No full textIn Russia, the problem of corporate governance has become a frequent subject for discussion. Stories now abound about questionable corporate governance practices, such as share dilution, asset stripping, transfer pricing, complex ownership structures, limiting shareholders from attending the shareholders meetings. These practices, which have come to constitute corporate governance abuses to company shareholders, are considered to be factors adversely affecting the investment climate. At first glance, these non-transparent practices are a collection of independent cases of managerial malfeasance that are abusive to investors. However, there seems to be an internal logic in these widely used practices, as they have been functional for Russian corporates to navigate through circumstances characterised by an imperfect formal framework. The aim of this paper is to analyse such functionalities of the practices in light of an evolution of corporate Russia. Taking Yukos Oil Company as a case study, the paper demonstrates that resorting to these practices was instrumental in a process of ensuring corporate survival and strengthening market position by establishing a coherent corporate entity. This paper emphasises that these practices represent rational and logical responses by economic agents to the prevailing conditions shaped by policy choices, political and macroeconomic environment, and institutions
Distinct Mechanisms for Induction and Tolerance Regulate the Immediate Early Genes Encoding Interleukin 1β and Tumor Necrosis Factor α
No full textInterleukin-1β and Tumor Necrosis Factor α play related, but distinct, roles in immunity and disease. Our study revealed major mechanistic distinctions in the Toll-like receptor (TLR) signaling-dependent induction for the rapidly expressed genes (IL1B and TNF) coding for these two cytokines. Prior to induction, TNF exhibited pre-bound TATA Binding Protein (TBP) and paused RNA Polymerase II (Pol II), hallmarks of poised immediate-early (IE) genes. In contrast, unstimulated IL1B displayed very low levels of both TBP and paused Pol II, requiring the lineage-specific Spi-1/PU.1 (Spi1) transcription factor as an anchor for induction-dependent interaction with two TLR-activated transcription factors, C/EBPβ and NF-κB. Activation and DNA binding of these two pre-expressed factors resulted in de novo recruitment of TBP and Pol II to IL1B in concert with a permissive state for elongation mediated by the recruitment of elongation factor P-TEFb. This Spi1-dependent mechanism for IL1B transcription, which is unique for a rapidly-induced/poised IE gene, was more dependent upon P-TEFb than was the case for the TNF gene. Furthermore, the dependence on phosphoinositide 3-kinase for P-TEFb recruitment to IL1B paralleled a greater sensitivity to the metabolic state of the cell and a lower sensitivity to the phenomenon of endotoxin tolerance than was evident for TNF. Such differences in induction mechanisms argue against the prevailing paradigm that all IE genes possess paused Pol II and may further delineate the specific roles played by each of these rapidly expressed immune modulators. © 2013 Adamik et al
Modelos de superficies e intercaras : transiciones de fase, desorden y aplicaciones
No full textEn esta memoria estudiamos varios modelos formulados en una dimensión. Primero estudiamos el modelo de sine-Gordon, que es adecuado para estudiar el crecimiento de superficies sólidas, encontrando un comportamiento de tamaño finito semejante a una transición de fase termodinámica. A continuación hemos presentado dos modelos de la transición de mojado de superficies. Hemos utilizado la versión con desorden de estos modelos para caracterizar la dependencia con la secuencia genética de la temperatura de desnaturalización del ADN. Combinando uno de los modelos de mojado con el de sine-Gordon proponemos un modelo nuevo, cuya versión con desorden nos permite hacer comparaciones con el modelo de sine-Gordon en dos dimensiones. De ello hacemos la conjetura que la fase superrugosa del modelo en dos dimensiones es en realidad una fase plana dominada por el desorden. A continuación, utilizando el modelo de Dauxois-Peyrard-Bishop, estudiamos el efecto de las burbujas de desnaturalización en el ADN. Nuestros resultados coinciden con los experimentales, de lo cual deducimos importantes consecuencias sobre la dinámica de burbujas. Finalmente, proponemos un modelo nuevo para el estudio de la dinámica de horquillas de ADN que nos permite poner a prueba las interpretaciones vigentes sobre los resultados experimentales
The 3He/4He Halo of the Kazbek Volcanic Center, Northern Caucasus
No full textManifestations of recent volcanism in the Greater
Caucasus are grouped in the El’brus and Kazbek volcanic
areas [1]. The last episodes of activity in the majority
of their eruptive centers date back to the Late
Holocene or even first centuries of the recent era
(El’brus Volcano) [2]. This implies potential volcanic
hazards in the Greater Caucasus. Therefore, it is important
to outline contours of this potentially hazardous
region with the maximal possible accuracy. The region
is characterized by indications of geodynamic stress,
such as recent eruptions, crustal deformations, seismic
activity, geothermal anomalies, and others. The 3He/4He value in natural gases can serve as one of such
indications.Published605–6083.2. Tettonica attivaJCR Journalreserve
Proof of principle for shotgun DNA mapping by unzipping
No full textAbility to map polymerases and nucleosomes on chromatin is important for understanding the impact of chromatin remodeling on key cellular processes. Current methods (such as ChIP and ChIP-chip) have produced a wealth of information that demonstrates this importance, but key information is elusive in these ensemble methods. We’re pursuing a new single-molecule chromatin mapping method based on unzipping native chromatin molecules with optical tweezers. The first step we are taking towards this ability is shotgun DNA mapping (SDM). This is the ability to identify the genomic location of a random DNA fragment based on its naked DNA unzipping forces compared with simulated unzipping forces of a published genome. We show that ~32 separate experimental unzipping curves for pBR322 were correctly matched to their simulated unzipping curves hidden in a background of the ~2700 sequences neighboring XhoI sites in the S. cerevisiae (yeast) genome. We describe this method and characterize its robustness as well as discuss future applications
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