7,410 research outputs found
Some Extended Classes of Distributions: Characterizations and Properties
Based on a simple relationship between two truncated moments and certain functions of the th order statistic, we characterize some extended classes of distributions recently proposed in the statistical literature, videlicet Beta-G, Gamma-G, Kumaraswamy-G and McDonald-G. Several properties of these extended classes and some special cases are discussed. We compare these classes in terms of goodness-of-fit criteria using some baseline distributions by means of two real data sets
Time-Reversal Symmetry Breaking and Decoherence in Chaotic Dirac Billiards
In this work, we perform a statistical study on Dirac Billiards in the
extreme quantum limit (a single open channel on the leads). Our numerical
analysis uses a large ensemble of random matrices and demonstrates the
preponderant role of dephasing mechanisms in such chaotic billiards. Physical
implementations of these billiards range from quantum dots of graphene to
topological insulators structures. We show, in particular, that the role of
finite crossover fields between the universal symmetries quickly leaves the
conductance to the asymptotic limit of unitary ensembles. Furthermore, we show
that the dephasing mechanisms strikingly lead Dirac billiards from the extreme
quantum regime to the semiclassical Gaussian regime
Importância da avaliação microbiológica na qualidade e segurança dos alimentos.
Abordagem técnológica. Abordagem metodológica. Relevância econômica, social e ambiental. Referências bibliográficasbitstream/CNPAB-2010/27380/1/doc120.pd
Elementos estruturadores da química orgânica implícitos na argumentação de professor e alunos de graduação
Mullins (2008) propõe que o bom desempenho em tópicos de Química Orgânica seria consequência do domínio adequado de elementos fundamentais quais sejam, eletronegatividade, ligação covalente polar, efeito estérico, efeito indutivo, ressonância e aromaticidade pois teriam valor instrumental na resolução de tarefas. O presente trabalho tem como foco investigar como estes elementos estruturantes estão presentes na argumentação desenvolvida por alunos e professores de graduação sob a luz da psicologia cognitiva. Como resultado propomos a estereoquímica como mais um elemento estruturador ao modelo de Mullins
Density functional theory for dense nematics with steric interactions
The celebrated work of Onsager on hard particle systems, based on the
truncated second order virial expansion, is valid at relatively low volume
fractions for large aspect ratio particles. While it predicts the
isotropic-nematic phase transition, it fails to provide a realistic equation of
state in that the pressure remains finite for arbitrarily high densities. In
this work, we derive a mean field density functional form of the Helmholtz free
energy for nematics with hard core repulsion. In addition to predicting the
isotropic-nematic transition, the model provides a more realistic equation of
state. The energy landscape is much richer, and the orientational probability
distribution function in the nematic phase possesses a unique feature: it
vanishes on a nonzero measure set in orientational space
Glutamate induces autophagy via the two-pore channels in neural cells
NAADP (nicotinic acid adenine dinucleotide phosphate) has been proposed as a second messenger for glutamate in neuronal and glial cells via the activation of the lysosomal Ca2+ channels TPC1 and TPC2. However, the activities of glutamate that are mediated by NAADP remain unclear. In this study, we evaluated the effect of glutamate on autophagy in astrocytes at physiological, non-toxic concentration. We found that glutamate induces autophagy at similar extent as NAADP. By contrast, the NAADP antagonist NED-19 or SiRNA-mediated inhibition of TPC1/2 decreases autophagy induced by glutamate, confirming a role for NAADP in this pathway. The involvement of TPC1/2 in glutamate-induced autophagy was also confirmed in SHSY5Y neuroblastoma cells. Finally, we show that glutamate leads to a NAADP-dependent activation of AMPK, which is required for autophagy induction, while mTOR activity is not affected by this treatment. Taken together, our results indicate that glutamate stimulates autophagy via NAADP/TPC/AMPK axis, providing new insights of how Ca2+ signalling glutamate-mediated can control the cell metabolism in the central nervous system
Colonização oral fúngica em indivíduos diabéticos
Poster apresentado nas XXI Jornadas de Ciências Farmacêuticas do ISCSEM - Instituto Superior de Ciências da Saúde Egas Moniz. 5-6 de Maio de 2015, Caparica
Oral Candida colonization in diabetic individuals non-carriers of dental prosthesis
Poster presented at the First International Congress of CiiEM - From Basic Sciences to Clinical Research. 27-28 November 2015, Egas Moniz, Caparica, Portuga
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