Elastoplastic analysis of plane steel frames under dynamic loading

Knowledge of structural behavior is essential for designing lighter constructions without affecting their safety and quality standards. Lack of levels and characteristics of dynamic response, for example, can lead to system failure during repetitive loading application, due to the accumulation of structural damage. Thus, it becomes necessary to use more complex theories, such as nonlinear formulations, avoiding simplifications in the process of analysis/design. Plastic analysis of steel structures enhances several benefits compared to the elastic’s, because one of the most important characteristics of this material, the ductility - ability to withstand large deformations before breaking - is fully considered. This allows for force redistribution after the yielding limit of some structural member’s cross section has been achieved. This property also promotes the absorption of energy, which becomes extremely important in structures subjected to seismic excitation

A Comparative Study of Pentaquark Interpolating Currents

In a diquark-diquark-antiquark picture of pentaquarks, we use two interpolating currents to calculate the mass of the recently measured $\Xi^{--}$ state in the framework of QCD sum rules. We show that, even though yielding similar values for $m_{\Xi^{--}}$ (and close to the experimental value), these currents differ from each other in what concerns the strength of the pole, convergence of the OPE and sensitivity to the continuum threshold parameter.Comment: 19 pages, 8 figures, replaced version accepted for publication in Phys. Lett.

Effect of prebiotic or probiotic supplementation and ileo rectal anastomosis on intestinal morphology of weaned piglets

Forty eight 21 days old piglets were used to compare the effect of prebiotic or probiotic supplementation and ileo rectal anastomosis on the morphology of the small intestine. Half of the piglets were maintained intact and the other half was subjected to an ileo rectal anastomosis (IRA). Each group of piglets received one of the following diets: 1) basal diet (C), 2) basal diet supplemented with a Xylo-oligosaccharide (XOS), 3) basal diet supplemented with a Saccharomyces cerevisiae (SC) and 4) basal diet supplemented with XOS and SC. Villus height was greatest with XOS and with XOS + SC, only in the ileum, as compared to controls. In the duodenum, crypt width was highest in the control group, but no significant differences were found in the jejunum and ileum. The IRA piglets had longer villi in the jejunum and shorter villi in the ileum. The crypt depth was greater in the duodenum and in the ileum of IRA piglets. Villus height/crypt depth was lower in the duodenum and in the ileum, in the IRA piglets. In conclusion, the XOS, but not the SC, moderately modified the intestinal morphology. The IRA modified the intestinal villus and crypt architecture but its consequence on the absorption of nutrients needs to be investigated

Revisiting consistency conditions for quantum states of systems on closed timelike curves: an epistemic perspective

There has been considerable recent interest in the consequences of closed timelike curves (CTCs) for the dynamics of quantum mechanical systems. A vast majority of research into this area makes use of the dynamical equations developed by Deutsch, which were developed from a consistency condition that assumes that mixed quantum states uniquely describe the physical state of a system. We criticise this choice of consistency condition from an epistemic perspective, i.e., a perspective in which the quantum state represents a state of knowledge about a system. We demonstrate that directly applying Deutsch's condition when mixed states are treated as representing an observer's knowledge of a system can conceal time travel paradoxes from the observer, rather than resolving them. To shed further light on the appropriate dynamics for quantum systems traversing CTCs, we make use of a toy epistemic theory with a strictly classical ontology due to Spekkens and show that, in contrast to the results of Deutsch, many of the traditional paradoxical effects of time travel are present.Comment: 10 pages, 6 figures, comments welcome; v2 added references and clarified some points; v3 published versio

The J/ψDDJ/\psi D D Vertex in QCD Sum Rules

The $J/\psi D D$ form factor is evaluated in a QCD sum rule calculation for both $D$ and $J/\psi$ off-shell mesons. We study the double Borel sum rule for the three point function of two pseudoscalar and one vector meson current. We find that the momentum dependence of the form factors is different if the $D$ or the $J/\psi$ meson is off-shell, but they lead to the same coupling constant in the $J/\psi D D$ vertex.Comment: 11 pages, Latex, 4 eps figure

Do Uso E Cobertura Da Terra à Experiência Etnográfica: Croquis E Imagens De Satélite Na Amazônia Rural Brasileira

The objective of this work is to explore two perspectives on land use and land cover change (LULC) in agricultural settlements of the Amazon region within an ethnographic experience: a “technical-scientific” view that defines LULC from afar using remote sensing techniques (classification and analysis of satellite imagery), and a “local” perspective that defines LULC by local farmers and residents using participatory sketch maps. This paper summarizes research results and the ethnographic experiences through which these perspectives may be formed, especially similarities and differences among the two. The analysis and results are divided into three views: one in which these perspectives are given equivalency across LULC studies; another describing the ethnographic experience according to an affective-intellectual intersectionality; and, finally, one that identifies a diagonally-shifting perspective, described as an expression of the spatial understanding of farmers produced through the ethnographic experience. © 2016, Centro em Rede de Investigacao em Antropologia. All rights reserved.20358360

Are Θ+\Theta^+ and the Roper resonance diquark-diquark-antiquark states?

We consider a $[ud]^2\bar{s}$ current in the QCD sum rule framework to study the mass of the recently observed pentaquark state $\Theta^+(1540)$, obtaining good agreement with the experimental value. We also study the mass of the pentaquark $[ud]^2\bar{d}$. Our results are compatible with the interpretation of the $[ud]^2\bar{d}$ state as being the Roper resonance N(1440), as suggested by Jaffe and Wilczek.Comment: 9 pages RevTex4 and 3 eps figures. Revised version accepted for publication in Phys. Lett.

Aspects of Soft and Spontaneous CP Violation

We study four different models for CP violation: the standard (KM) model, the aspon model of spontaneous breaking and two models of soft breaking. In all except the standard model, the strong CP problem is addressed and solved. Testable predictions for the area of the unitarity triangle and for (epsilon'/epsilon)_K are emphasized. The issue of CP violation may well become the first place where the standard model of particle theory is shown definitively to be deficient. There are two reasons for expecting this to happen: (1) the strong CP problem is still not understood in the unadorned standard model and (2) the KM mechanism, although unquestionably present, may not provide the full explanation of epsilon_K and (epsilon'/epsilon)_K.Comment: 24 pages LaTeX including 4 figures. Minor modification to analysis of lower bound for d_n, summarized in new Table I

Nitrate and Phosphate Toxicity on Post Larvae of the Giant Fresh Water Prawn (Macrobrachium rosenbergii) Individual and Synergistic Effects

The indiscriminate use of fertilizers has resulted in nutrient enrichment giving rise toeutrophic conditions in many freshwater bodies in Sri Lanka. Few studies have investigatedeffects of field levels of nitrate and phosphate on commercial freshwater species. The presentstudy therefore attempted to assess the individual and synergistic effects of nitrate andphosphate on post larvae of the Giant fresh Water Prawn Macrobrachium rosenbergii, whichare released in large quantities into reservoir systems of the dry zone of Sri Lanka.The post larvae were collected from a culture facility in Pambala, Chilaw, and wereacclimatized. After the measurement of the initial body lengths the larvae were introducedinto 500 ml glass beakers (n=10 per beaker) containing five field based concentrations ofeither nitrate (0.01 – 100 mg l-1) or phosphate (0.001 – 10 mg l-1). Controls and treatmentswere maintained in triplicate. Synergistic effects were also tested for 0.1 mg l-1 of phosphatewith three concentrations of nitrate (0.1, 1, 10 mg l-1). Survival, growth and the feedingbehaviour of the post larvae were monitored as end points of the empirical acute toxicity (96hr) trials. Results revealed that both nitrate and phosphate enhances mortality levels in prawnlarvae when acting alone at concentrations of 0.01 mg l-1and above for nitrate and 0.001mgl-1and above for phosphate. For instance, mortality in controls was 13.3 %, and for the twonutrients at the lowest test levels i.e. 0.01 mg l-1 of nitrate and 0.001 mg l-1 of phosphate, were23% and 20%, respectively. The synergistic effects with both nitrate and phosphate werelower than the additive effects of each, at all tested levels, but were greater than the recordedindividual effects. The synergistic mortality with 10 mg l-1 of nitrate and 0.1 mg l-1 ofphosphate was greater than mortality induced by each nutrient acting alone. In contrast tomortality, effects on growth were not apparent with either nitrate or phosphate acting alonenor synergistically, while the phosphate alone and both nutrients acting synergistically,appeared to cause reduced feeding. These findings highlight the need for investigating effectsof nutrient enrichment, and specifically their synergistic effects, on commercially exploitedspecies in order to predict levels of sustainability of the inland fishery resources of Sri Lanka.