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Search Results: 1 - 10 of 191349 matches for " D Elkonin "
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Enfrentando o problema dos estágios no desenvolvimento mental das crian?as
Elkonin, D. B.;
Educar em Revista , 2012, DOI: 10.1590/S0104-40602012000100011
Abstract: the aim of the article is to discuss the naturalistic and evolutionary concept of mental development, especially in theoretical models which strongly defend a conception of human mental development into stages, relating chronological age and intra and interindividual changes. such theoretical models dichotomize child psychology in need-motivational and cognitive-intellectual aspects. intending to surpass this dichotomy, elkonin considers that human mental development is better understood as a dialectical movement of the assimilation, by the child, since its birth, of the objectives, reasons and norms of human relations and of the acquisition and internalization of the socio-cultural and historically evolved modes of action with objects, within a social group. this dialectical perspective of understanding the development allows: 1. to see the process of mental development as an ascending spiral, rather than linearly, 2. to explain the functional significance of the different periods of development, clarifying their transitional patterns, and 3. to serve as an aid in resolving the question of the susceptibility of the various stages of child development to particular types of influence.
Positive and negative emotional responses to work-related trauma of intensive care nurses in private health care facilities
D Elkonin, L van der Vyver
Health SA Gesondheid , 2011,
Abstract: Intensive care nursing is a stressful occupation and nurses are continually subjected to both primary and secondary trauma. Responses may be positive in the form of compassion satisfaction, or negative in the form of compassion fatigue. However, nurses tend to deny the negative impact of secondary trauma which leads to the silencing response and subsequent burnout. This article explores and describes the presence of these emotions and the relationships between them. A quantitative approach with a non-probability sampling method was used. The sample consisted of 30 registered nurses working in private health care intensive care units in East London, Eastern Cape. Data were gathered via the Professional Quality of Life Scale: Compassion Satisfaction and Fatigue Subscales – Revision IV (ProQOL – R-IV) and the Silencing Response Scale and were analysed according to descriptive statistics and correlation coefficients. Findings suggest a high risk for compassion fatigue, a moderate risk for burnout and the silencing response and moderate potential for compassion satisfaction. A marked negative relationship was found between compassion satisfaction and burnout and a substantial positive relationship between compassion fatigue and burnout, as well as compassion fatigue and the silencing response. Intensiewesorgverpleging is ‘n stresvolle beroep en verpleegsters word gedurig aan beide primêre en sekondêre trauma blootgestel. Reaksie hierop kan óf positief wees, in die vorm van empatie-tevredenheid, óf negatief, in die vorm van empatie-uitputting. Verpleegsters is egter geneig om die negatiewe impak van sekondêre trauma te ontken, wat gevolglik tot stilswye en uitbranding kan lei. Hierdie artikel ondersoek en beskryf die teenwoordigheid en verwantskap tussen hierdie emosies. ‘n Kwantitatiewe benadering met ‘n nie-waarskynlikheidsteekproefmetode is gebruik. Die steekproef het bestaan uit 30 geregistreerde verpleegsters wat in privaat-intensiewesorgeenhede in Oos-Londen in die Oos-Kaap werk. Data is met behulp van die vierde hersiening van die ’Professional Quality of Life Scale: Compassion Satisfaction and Fatigue Subscales’ en die ’Silencing Response Scale’ ingevorder en verwerk met verwysing na beskrywende statistieke en korrelasieko ffisiente. Die resultate dui op ‘n ho risiko vir empatie-uitputting, ‘n matige risiko vir uitbranding en die stilswye-reaksie, sowel as ‘n matige potensiaal vir empatie-tevredenheid. ‘n Beduidende negatiewe verwantskap blyk tussen empatie-tevredenheid en uitbranding te bestaan, terwyl ‘n aansienlik positiewe verwantskap tussen empatie-uitputting en uitbranding en empatieuitputting en die stilswye-reaksie bestaan.
Cytological Investigation of Pollen Development in Sorghum Line with Male Sterility Induced by Sodium Ascorbate in Tissue Culture  [PDF]
Marina I. Tsvetova, Lev A. Elkonin
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.47A1002
Abstract:

Investigation of male sterility mutations is an effective approach for identification of genes involved in anther and pollen development. The comparison of cytological phenotypes of newly induced mutants with phenotypes determined by already known genes favors elucidation of genetic control of diverse microsporo- and gametogenesis stages. In this paper, we describe pollen development in the grain sorghum line Zh10-asc1 with mutation of male sterility. This line was obtained from callus culture treated by sodium ascorbate. A wide spectrum of abnormalities in microsporogenesis have been found, such as cytomixis, chromosomal laggards, chromosome disjunction, adhesion of chromosomes, disturbed cytokinesis, and others. In tapetum, the cells with one nucleus, with unequal nuclei, and with micronuclei have been observed. During pollen grain (PG) maturation abnormalities in starch accumulation and delay of development often took place. In mature anthers, a variety of pollen grain types have been revealed: fertile, of irregular shape, incompletely filled with starch, PGs delayed at the uni-nucleate or bi-nucleate gametophyte stages, with partially or fully degenerated contents, and with abnormal coloration. Variation in spectrum and the frequency of disturbances between the flowers of one and the same plant have been revealed. The reasons for significant genetic and epigenetic instability are discussed.

Positive and negative emotional responses to workrelated trauma of intensive care nurses in private health care facilities
Diane Elkonin,Lizelle Van der Vyver
Health SA Gesondheid , 2011, DOI: 10.4102/hsag.v16i1.436
Abstract: Intensive care nursing is a stressful occupation and nurses are continually subjected to both primary and secondary trauma. Responses may be positive in the form of compassion satisfaction, or negative in the form of compassion fatigue. However, nurses tend to deny the negative impact of secondary trauma which leads to the silencing response and subsequent burnout. This article explores and describes the presence of these emotions and the relationships between them. A quantitative approach with a non-probability sampling method was used. The sample consisted of 30 registered nurses working in private health care intensive care units in East London, Eastern Cape. Data were gathered via the Professional Quality of Life Scale: Compassion Satisfaction and Fatigue Subscales – Revision IV (ProQOL – R-IV) and the Silencing Response Scale and were analysed according to descriptive statistics and correlation coefficients. Findings suggest a high risk for compassion fatigue, a moderate risk for burnout and the silencing response and moderate potential for compassion satisfaction. A marked negative relationship was found between compassion satisfaction and burnout and a substantial positive relationship between compassion fatigue and burnout, as well as compassion fatigue and the silencing response. Opsomming Intensiewesorgverpleging is ‘n stresvolle beroep en verpleegsters word gedurig aan beide primêre en sekondêre trauma blootgestel. Reaksie hierop kan óf positief wees, in die vorm van empatie-tevredenheid, óf negatief, in die vorm van empatie-uitputting. Verpleegsters is egter geneig om die negatiewe impak van sekondêre trauma te ontken,wat gevolglik tot stilswye en uitbranding kan lei. Hierdie artikel ondersoek en beskryf die teenwoordigheid en verwantskap tussen hierdie emosies. ‘n Kwantitatiewe benadering met ‘n nie-waarskynlikheidsteekproefmetode is gebruik. Die steekproef het bestaan uit 30 geregistreerde verpleegsters wat in privaat-intensiewesorgeenhede in Oos-Londen in die Oos-Kaap werk. Data is met behulp van die vierde hersiening van die ’Professional Quality of Life Scale: Compassion Satisfaction and Fatigue Subscales’ en die ’Silencing Response Scale’ingevorder en verwerk met verwysing na beskrywende statistieke en korrelasieko ffisiente. Die resultate dui op ‘n ho risiko vir empatie-uitputting, ‘n matige risiko vir uitbranding en die stilswye-reaksie, sowel as ‘n matige potensiaal vir empatie-tevredenheid. ‘n Beduidende negatiewe verwantskap blyk tussen empatie-tevredenheid en uitbranding te bestaan, terwyl ‘n aansienlik positiewe verwantskap tus
Explicit breaking of supersymmetry by non-perturbative effects
A. Casher,V. Elkonin,Y. Shamir
Physics , 1994,
Abstract: Instanton effects in a family of completely massive Higgs models with N=1 supersymmetry are investigated. The models have $N_c=2$ and $N_f\ge 2$. In each model, we show that a certain gauge invariant correlation function depends in a non-trivial way on its coordinates, in spite of the fact that supersymmetry requires its constancy. This means that non-perturbative effects break supersymmetry explicitly in the one instanton sector. We also show that condensates arising in the point-like limit of the above correlation functions can in principle be used to induce the Electro-Weak scale.
Anomalous Supersymmetry Breaking by Instantons
A. Casher,V. Elkonin,Y. Shamir
Physics , 1995,
Abstract: We show that instantons violate a supersymmetric identity in a classically supersymmetric Higgs model with no massless fermions. This anomalous breaking arises because the correct perturbative expansion in the instanton sector is not supersymmetric. The attempt to construct a manifestly supersymmetric expansion generates infra-red divergences.
Ontogenetically-regulated male sterility in tissue culture - induced and spontaneous sorghum mutants
Elkonin L.A.,Belyaeva E.V.
Genetika , 2003, DOI: 10.2298/gensr0302099e
Abstract: Variability of male fertility expression in the AS-1 line, a somaclonal variant obtained from tissue culture of CMS-plant, and in the progeny of revenant '124-1' obtained from fertile tiller, which developed on CMS-plant transferred from the field to the greenhouse, was investigated. Both revertants were characterized by similar expression of male fertility during plant ontogenesis: the panicle on the main tiller was almost completely sterile whereas formation of fertile pollen grains and seed set were observed on the panicles of the shoot tillers. A clear basipetal gradient of male fertility was manifested on all panicles: the base had significantly higher per cent of fertile pollen grains in comparison with the middle part, while in the top the anthers were either absent or had few sterile pollen grains. Such an ontogenetically-regulated restoration of male fertility was controlled by nuclear genes and could be transferred through the pollen in crosses with progenitor CMS-line. Growing of AS-1 plants in the growth chambers simultaneously under a long (16/8) and a short (12/12) daylength conditions demonstrated that differences of fertility level in different tillers was not caused by change of photoperiod during plant ontogenesis and functioning of photoperiod-sensitive fertility restoring gene. Whereas, the ontogenetically-regulated expression of male fertility in both revenants was temperature-dependent and was clearly manifested under relatively cool conditions during 2-week period before the beginning of anthesis of the first panicle (average daily temperature 21°C). The increase of the average daily temperature by 2-3 С resulted in sharp increase of male fertility level. Possibility of using AS-1 line in a new "two-line system" of hybrid seed production, which require only two lines (sterile mutant and fertility restorer), is discussed.
AGROBACTERIUM-MEDIATED GENETIC TRANSFORMATION OF SORGHUM USING TISSUE CULTURE-BASED AND POLLEN-MEDIATED APPROACHES
Elkonin L.A.,O.N. Nosova,J.V. Italianskaya
Journal of Stress Physiology & Biochemistry , 2012,
Abstract: Genetic transformation is a powerful tool for genetic improvement of arable crops. Genetic engineering approaches are especially important for modification of starch and protein contents, vitamin and micronutrient concentration, improvement of nutritive value of protein fractions, and increase tolerance to environmental stresses. Application of transgenic technologies for genetic improvement of sorghum, a highly productive heat tolerant and drought resistant crop, is extremely important since climate aridization in many regions all over the globe hampers sustainable production of traditional cereals, such as wheat, maize and barley. However, sorghum, in spite of great number of investigations, is one of the most recalcitrant crop species to genetic modification. The most frequently reported problems are a low frequency of transformation and silencing of transgenes. Using the A. tumefaciens strain AGL0/p35SGIB with the bar and gus-intron genes under the nos and CaMV35S promoters, respectively, we studied different methods of Agrobacterium-mediated genetic transformation of the grain sorghum: in vitro culture-based techniques, by inoculation of immature embryos or embryo-derived calli, and pollen-mediated approach, by inoculation of flowering panicles. Four lines of grain sorghum – Milo-10, [9E] Milo-10 (CMS-line), KVV-114, and KVV-45 – were used. In both approaches, for activation of vir-genes agrobacterial cell suspension was grown in the AB or modified AB media with acetosyringone at room temperature. In vitro culture approach was effective for obtaining transgenic plants in the lines Milo-10 and KVV-45, which were able to produce embryogenic callus from immature embryos after their co-cultivation with agrobacterial cell suspension. Callus cultures tolerant to glufosinate ammonium (GA) and capable to plant regeneration were obtained. The frequency of immature embryos producing PCR-positive transgenic plants varied in different experiments from 4.5% to 5.4%. Cultivation conditions increasing embryogenic potentials of cultured tissues were the key factors for obtaining of transgenic plants. In the Milo-10, transgenic plants were regenerated also from established embryogenic cultures after their co-cultivation with agrobacterial cell suspension, their frequency was 1.7%. Immature embryos of KVV-114 did not produce embryogenic callus, and in this line transgenic plants were obtained by inoculation of flowering panicles at anthesis. In the progeny of each inoculated panicle the frequency of fertile PCR-positive transgenic plants survived BASTA application w
Electrical Conductivity of Collapsed Multilayer Graphene Tubes  [PDF]
D. Mendoza
World Journal of Nano Science and Engineering (WJNSE) , 2012, DOI: 10.4236/wjnse.2012.22009
Abstract: Synthesis of multilayer graphene on copper wires by a chemical vapor deposition method is reported. After copper etching, the multilayer tube collapses forming stripes of graphitic films, their electrical conductance as a function of temperature indicate a semiconductor-like behavior. Using the multilayer graphene stripes, a cross junction is built and owing to its electrical behavior we propose that a tunneling process exists in the device.
Porous Carbon Grown by Chemical Vapor Deposition on Copper Substrates  [PDF]
D. Mendoza
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.38003
Abstract: Amorphous porous carbon was synthesized by chemical vapor deposition on copper substrates. The average size of the pores is around 1.2 microns with some small pores decorating the big ones. Lamellar samples of this carbonaceous material can be separated from the copper support and may be useful as electrode due to its low electrical resistivity of the order of 0.4 Ωcm.
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