516 research outputs found

    Thermogravimetry and neutron thermodiffractometry studies of the H-YBa2Cu3O7 system.

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    The high Tc superconducting oxide YBa2Cu3O7¿x reacts with hydrogen gas. Thermogravimetric, X-ray and neutron scattering experiments allow us to propose a two-step type of hydrogen bonding. Firstly, a few hydrogen atoms fill some oxygen vacancies and may favourably modify the electron state, giving rise to a slight increase in the critical temperature. Secondly, after a prolonged heating period, the collapse of the YBa2Cu3O7¿x type framework and of superconductivity were observed, and a new, highly hydrogenated material appeared

    A Generalized Class of Exponentiated Modified Weibull Distribution with Applications

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    In this paper, a new class of five parameter gamma-exponentiated or generalized modified Weibull (GEMW) distribution which includes exponential, Rayleigh, Weibull, modified Weibull, exponentiated Weibull, exponentiated exponential, exponentiated modified Weibull, exponentiated modified exponential, gamma-exponentiated exponential, gamma-exponentiated Rayleigh, gamma-modified Weibull, gamma-modified exponential, gamma-Weibull, gamma-Rayleigh and gamma-exponential distributions as special cases is proposed and studied. Mathematical properties of this new class of distributions including moments, mean deviations, Bonferroni and Lorenz curves, distribution of order statistics and Renyi entropy are presented. Maximum likelihood estimation technique is used to estimate the model parameters and applications to real data sets presented in order to illustrate the usefulness of this new class of distributions and its sub-models

    Stakeholder Perception in the Organizational Environment Focusing on Behavior

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    Behavior has meaning for the organizational climate, leading to studies such as this related to stakeholder perception in the institutional environment. This task is based on the Behavioral Management Theory and the additional concepts required. It was sought to know the relation of the intervening factors, from the method of case study of qualitative-quantitative nature, in order to establish comparisons and to produce the results. The general objective is to study the stakeholder perception process in the organizational environment focused on the behavioral effect and it has as specific objectives to treat and identify the relationship of the intervening factors with the organizational climate in the face of data collected among the consulted, to perform the SWOT on the positioning of individuals in the organizational environment and how this perception is characterized in the face of the organizational climate present in the consulted organ. The research indicates that the majority of respondents stated that the organizational climate present in the organ consulted satisfactory, propitiates the good organizational environment in the organ. Confrontation between the theoretical indicatives and the reality identified in the institutional environment allows to affirm that in fact there is internal influence, such as the motivation and external organization, as the possibility of losing the employee attracted by other opportunities outside the institution. Analysis allows to identify the need for physical improvement of the professional space, and in the interaction between stakeholders; redistribution of work that avoids overload; but the motivation and good internal relation between the individuals surpass the expectation. This work interests the managers in public organs and other interested in the subject here treated

    Innovating Management Control by Dynamic Analysis of Pareto in a Hotel Business

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    This paper deals with the Pareto Analysis of problems observed and criticized by clients in a hotel establishment in the municipality of Porto Velho, capital of the State of Rondocirc;nia. The general objective of the research is to study the use of Pareto Analysis in these problems that annoy the clients; (1), to group the data in descending order of frequency and to calculate the cumulative values (2), and indicating innovation for managerial control through a tool for Pareto Analysis in a dynamical way (3). The methodology of the qualitative-quantitative approach, of an exploratory nature, is adopted; the bibliographic survey and the field research are applied in support of the case study. Through the database system that the company under study possesses, the data necessary to be used in the Pareto Analysis are obtained, completing the first specific objective; the grouping of these data in descending order of absolute frequency, the calculation of the cumulative values, the preparation of the Pareto Diagram and the analysis carried out successfully completed the second specific objective; and finally the study is finished with the creation of a tool that allows a more dynamic analysis of the scenario in which the company is inserted, as a proposal of innovation for the institution to perform its practical and dynamic analyzes, useful in decision making. This study is a contribution of the academy to managers who work with complex decisions in hotel or related establishments interested in customer satisfaction

    Origins and clinical implications of the brain tumor stem cell hypothesis

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    With the advent of the cancer stem cell hypothesis, the field of cancer research has experienced a revolution in how we think of and approach cancer. The discovery of "brain tumor stem cells" has offered an explanation for several long-standing conundrums on why brain tumors behave the way they do to treatment. Despite the great amount of research that has been done in order to understand the molecular aspects of malignant gliomas, the prognosis of brain tumors remains dismal. The slow progress in extending the survival of patients with malignant CNS neoplasms is very likely due to poor understanding of the cell of origin in these tumors. This review article discusses the progress in our understanding of brain tumor stem cells as the cell of origin in brain cancers. We review the different proposed mechanisms of how brain tumor stem cells may originate, the intracellular pathways disrupted in the pathogenesis of BTSCs, the molecular markers used to identify BTSCs, the molecular mechanisms of cancer initiation and progression, and finally the clinical implications of this research

    Thermodynamics of the incommensurate state in Rb_2WO_4: on the Lifshitz point in A`A``BX_4 compounds

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    We consider the evolution of the phase transition from the parent hexagonal phase P63/mmcP6_{3}/mmc to the orthorhombic phase PmcnPmcn that occurs in several compounds of AABX4A'A''BX_{4} family as a function of the hcp lattice parameter c/ac/a. For compounds of K2SO4K_{2}SO_{4} type with c/ac/a larger than the threshold value 1.26 the direct first-order transition PmcnP63/mmcPmcn-P6_{3}/mmc is characterized by the large entropy jump Rln2Rln2. For compounds Rb2WO4Rb_{2}WO_{4}, K2MoO4K_{2}MoO_{4}, K2WO4K_{2}WO_{4} with c/a<1.26c/a<1.26 this transition occurs via an intermediate incommensurate (Inc)(Inc) phase. DSC measurements were performed in Rb2WO4Rb_{2}WO_{4} to characterize the thermodynamics of the PmcnIncP63/mmcPmcn-Inc-P6_{3}/mmc transitions. It was found that both transitions are again of the first order with entropy jumps 0.2Rln2and0.2Rln2 and 0.3Rln2.Therefore,at. Therefore, at c/a ~ 1.26the the A'A''BX_{4}compoundsrevealanunusualLifshitzpointwherethreefirstordertransitionlinesmeet.Weproposethecouplingofcrystalelasticitywith compounds reveal an unusual Lifshitz point where three first order transition lines meet. We propose the coupling of crystal elasticity with BX_{4}$ tetrahedra orientation as a possible source of the transitions discontinuity.Comment: 13 pages,1 Postscript figure. Submitted as Brief Report to Phys. Rev. B, this paper reports a new work in Theory and Experiment, directed to Structural Phase Transition

    T-Bet and Eomes Regulate the Balance between the Effector/Central Memory T Cells versus Memory Stem Like T Cells

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    Memory T cells are composed of effector, central, and memory stem cells. Previous studies have implicated that both T-bet and Eomes are involved in the generation of effector and central memory CD8 T cells. The exact role of these transcription factors in shaping the memory T cell pool is not well understood, particularly with memory stem T cells. Here, we demonstrate that both T-bet or Eomes are required for elimination of established tumors by adoptively transferred CD8 T cells. We also examined the role of T-bet and Eomes in the generation of tumor-specific memory T cell subsets upon adoptive transfer. We showed that combined T-bet and Eomes deficiency resulted in a severe reduction in the number of effector/central memory T cells but an increase in the percentage of CD62LhighCD44low Sca-1+ T cells which were similar to the phenotype of memory stem T cells. Despite preserving large numbers of phenotypic memory stem T cells, the lack of both of T-bet and Eomes resulted in a profound defect in antitumor memory responses, suggesting T-bet and Eomes are crucial for the antitumor function of these memory T cells. Our study establishes that T-bet and Eomes cooperate to promote the phenotype of effector/central memory CD8 T cell versus that of memory stem like T cells. © 2013 Li et al

    Direct Patterning of Organic Functional Polymers through Conventional Photolithography and Noninvasive Cross-Link Agents

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    A new technique for direct patterning of functional organic polymers using commercial photolithography setups with a minimal loss of the materials' performances is reported. This result is achieved through novel cross-link agents made by boron- and fluorine-containing heterocycles that can react between themselves upon UV- and white-light exposure
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