9,271 research outputs found
Enhancement of the nonlinear optical absorption of the E7 liquid crystal at the nematic-isotropic transition
We present an experimental study of the nonlinear optical absorption of the
eutectic mixture E7 at the nematic-isotropic phase transition by the Z-scan
technique, under a continuos wave excitation at 532 nm. In the nematic region,
the effective nonlinear optical coefficient \beta for an extraordinary beam is
negative and for an ordinary beam is positive, being null in the isotropic
phase. The parameter S_{NL} defined in terms of the nonlinear absorption
coefficients in a similar way than the optical order parameter from the linear
dichoic ratio behavies like an order parameter with a critical exponent
0.22+-0.05, in good agreement with the tri-critical hipothesis of the N-I
transition.Comment: 11 pages, 6 figures, to be published in the vol 42 of the Brazilian
Jurnal of physic
Foraminifers from the Lower-Middle Jurassic boundary of the Lusitanian Basin: Murtinheira section (North Sector) and Zambujal de Alcaria section (Central Sector)
Comunicação apresentada ao VIII Congresso Nacional de Geologia, em Braga (9-16 de Julho 2010)análise da diversidade taxonómica e das abundâncias relativas nas associações de
foraminíferos da passagem Jurássico Inferior-Médio em dois sectores da Bacia Lusitânica indica que tais
associações apresentam diferenças nas suas composições, aparentemente homogéneas. Assim, as
associações de zonas proximais (perfil de Zambujal de Alcaria) são mais abundantes e com maior
diversidade que as registadas em zonas distais (perfil da Murtinheira). Além disso, a maioria dos taxa
comuns em ambas as zonas apresentam diferenças nas suas abundâncias relativas, que parecem resultar
de preferências paleo-ambientais distintas.The analysis of diversity and relative abundances of foraminiferal assemblages from two
sections located in the Lusitanian Basin, and corresponding to the Lower-Middle Jurassic boundary,
shows that these apparently homogeneous assemblages present differences in their composition.
Assemblages from shallow zones (Zambujal de Alcaria section) show higher diversity and abundance
than assemblages from deeper zones (Murtinheira section). Species recorded in both areas show distinct
values on their relative abundances, as a possible relationship with their palaeo-environmental
preferences
Caracterização do cruzamento entre as raças suínas landrace x large White x moura pra formação de híbridos da linha fêmea.
Even Galois Representations and the Fontaine--Mazur conjecture II
We prove, under mild hypotheses, that there are no irreducible
two-dimensional_even_ Galois representations of \Gal(\Qbar/\Q) which are de
Rham with distinct Hodge--Tate weights. This removes the "ordinary" hypothesis
required in previous work of the author. We construct examples of irreducible
two-dimensional residual representations that have no characteristic zero
geometric (= de Rham) deformations.Comment: Updated to take into account suggestions of the referee; the main
theorems remain unchange
A consistent approach for probabilistic residential flood loss modeling in Europe
In view of globally increasing flood losses, a significantly improved and more efficient flood risk management and adaptation policy are needed. One prerequisite is reliable risk assessments on the continental scale. Flood loss modeling and risk assessments for Europe are until now based on regional approaches using deterministic depth‐damage functions. Uncertainties associated with the risk estimation are hardly known. To reduce these shortcomings, we present a novel, consistent approach for probabilistic flood loss modeling for Europe, based on the upscaling of the Bayesian Network Flood Loss Estimation MOdel for the private sector, BN‐FLEMOps. The model is applied on the mesoscale in the whole of Europe and can be adapted to regional situations. BN‐FLEMOps is validated in three case studies in Italy, Austria, and Germany. The officially reported loss figures of the past flood events are within the 95% quantile range of the probabilistic loss estimation, for all three case studies. In the Italian, Austrian, and German case studies, the median loss estimate shows an overestimation by 28% (2.1 million euro) and 305% (5.8 million euro) and an underestimation by 43% (104 million euro), respectively. In two of the three case studies, the performance of the model improved, when updated with empirical damage data from the area of interest. This approach represents a step forward in European wide flood risk modeling, since it delivers consistent flood loss estimates and inherently provides uncertainty information. Further validation and tests with respect to adapting the model to different European regions are recommended
Foraminifera from the Lower-Middle Jurassic of the Lusitanian Basin, Portugal: biostratigraphic and palaeocological significance
Existence of positive solutions of a superlinear boundary value problem with indefinite weight
We deal with the existence of positive solutions for a two-point boundary
value problem associated with the nonlinear second order equation
. The weight is allowed to change its sign. We assume
that the function is
continuous, and satisfies suitable growth conditions, so as the case
, with , is covered. In particular we suppose that is
large near infinity, but we do not require that is non-negative in a
neighborhood of zero. Using a topological approach based on the Leray-Schauder
degree we obtain a result of existence of at least a positive solution that
improves previous existence theorems.Comment: 12 pages, 4 PNG figure
Efeito de diferentes inseticidas no controle de Dalbulus maidis e Elasmopalpus lignosellus em milho.
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