Loop representation of charged particles interacting with Maxwell and Chern-Simons fields

The loop representation formulation of non-relativistic particles coupled with abelian gauge fields is studied. Both Maxwell and Chern-Simons interactions are separately considered. It is found that the loop-space formulations of these models share significant similarities, although in the Chern-Simons case there exists an unitary transformation that allows to remove the degrees of freedom associated with the paths. The existence of this transformation, which allows to make contact with the anyonic interpretation of the model, is subjected to the fact that the charge of the particles be quantized. On the other hand, in the Maxwell case, we find that charge quantization is necessary in order to the geometric representation be consistent.Comment: 6 pages, improved versio

Fuzzy logic as a decision-making support system for the indication of bariatric surgery based on an index (OBESINDEX) generated by the association between body fat and body mass index

Background: A Fuzzy Obesity Index (OBESINDEX) for use as an alternative in bariatric surgery indication (BSI) is presented. The search for a more accurate method to evaluate obesity and to indicate a better treatment is important in the world health context. BMI (body mass index) is considered the main criteria for obesity treatment and BSI. Nevertheless, the fat excess related to the percentage of Body Fat (%BF) is actually the principal harmful factor in obesity disease that is usually neglected. This paper presents a new fuzzy mechanism for evaluating obesity by associating BMI with %BF that yields a fuzzy obesity index for obesity evaluation and treatment and allows building up a Fuzzy Decision Support System (FDSS) for BSI.

Methods: Seventy-two patients were evaluated for both BMI and %BF. These data are modified and treated as fuzzy sets. Afterwards, the BMI and %BF classes are aggregated yielding a new index (OBESINDEX) for input linguistic variable are considered the BMI and %BF, and as output linguistic variable is employed the OBESINDEX, an obesity classification with entirely new classes of obesity in the fuzzy context as well is used for BSI.

Results: There is a gradual, smooth obesity classification and BSI when using the proposed fuzzy obesity index when compared with other traditional methods for dealing with obesity.

Conclusion: The BMI is not adequate for surgical indication in all the conditions and fuzzy logic becomes an alternative for decision making in bariatric surgery indication based on the OBESINDEX

Viabilidade econômica do sistema agroflorestal grevílea x café na Região Norte do Paraná.

Na década de 70, o Instituto Brasileiro do Café - IBC incentivou a introdução de Grevillea robusta nos cafezais da região Norte do Paraná, na forma de quebra-ventos, apesar de sua implantação não haver seguido padrões técnicos adequados. Para a análise da viabilidade econômica da utilização desses quebra-ventos, foram comparados os benefícios diretos (custos x renda) do Sistema Puro Café e do Sistema Agroflorestal Grevílea x Café, utilizando um aplicativo de apropriação e análise de custos, o SAAC florestal (Hildebrandt, 1995). As planilhas do aplicativo foram preenchidas separadamente para os dois sistemas. O Sistema Puro Café contou com dados secundários de custos de produção e rendas fornecidos por órgãos públicos e privados. Para a análise do Sistema Agroflorestal, foram utilizados os mesmos dados referentes à produção monocultural de café, acrescidos dos dados de custos de produção e rendas da espécie florestal obtidos por meio de questionários aplicados junto a proprietários rurais e serrarias da região de estudo. Os resultados obtidos permitiram constatar que a espécie florestal introduzida no sistema representa um custo adicional insignificante para o produtor rural e ocupa uma área mínima, ou seja, uma média de 58 árvores por hectare. A renda obtida com a venda da madeira para serrarias gera um aumento significativo da renda no último ano, de 32,22%, permitindo o pagamento dos custos de implantação ou grande parte dos custos de reforma da atividade. Portanto, a utilização da grevílea nos cafezais é altamente positiva do ponto de vista do aumento da rentabilidade da atividade e da tranquilidade do produtor, pois pode representar uma poupança ao longo do ciclo da cultura cafeeira, assegurando a continuidade desta atividade por meio do pagamento da reforma com o corte da madeira

Slip behavior in liquid films on surfaces of patterned wettability: Comparison between continuum and molecular dynamics simulations

We investigate the behavior of the slip length in Newtonian liquids subject to planar shear bounded by substrates with mixed boundary conditions. The upper wall, consisting of a homogenous surface of finite or vanishing slip, moves at a constant speed parallel to a lower stationary wall, whose surface is patterned with an array of stripes representing alternating regions of no-shear and finite or no-slip. Velocity fields and effective slip lengths are computed both from molecular dynamics (MD) simulations and solution of the Stokes equation for flow configurations either parallel or perpendicular to the stripes. Excellent agreement between the hydrodynamic and MD results is obtained when the normalized width of the slip regions, $a/\sigma \gtrsim {\cal O}(10)$, where $\sigma$ is the (fluid) molecular diameter characterizing the Lennard-Jones interaction. In this regime, the effective slip length increases monotonically with $a/\sigma$ to a saturation value. For $a/\sigma \lesssim {\cal O}(10)$ and transverse flow configurations, the non-uniform interaction potential at the lower wall constitutes a rough surface whose molecular scale corrugations strongly reduce the effective slip length below the hydrodynamic results. The translational symmetry for longitudinal flow eliminates the influence of molecular scale roughness; however, the reduced molecular ordering above the wetting regions of finite slip for small values of $a/\sigma$ increases the value of the effective slip length far above the hydrodynamic predictions. The strong inverse correlation between the effective slip length and the liquid structure factor representative of the first fluid layer near the patterned wall illustrates the influence of molecular ordering effects on slip in non-inertial flows.Comment: 12 pages, 10 figures Web reference added for animations: http://www.egr.msu.edu/~priezjev/bubble/bubble.htm

An Investigation of the KFK_{F}-type Lorentz-Symmetry Breaking Gauge Models in N=1N=1-Supersymmetric Scenario

In this work, we present two possible venues to accomodate the $K_{F}$-type Lorentz-symmetry violating Electrodynamics in an $N=1$-supersymmetric framework. A chiral and a vector superfield are chosen to describe the background that signals Lorentz-symmetry breaking. In each case, the $\ K_{\mu \nu \kappa \lambda }$-tensor is expressed in terms of the components of the background superfield that we choose to describe the breaking. We also present in detail the actions with all fermionic partners of the background that determine $\ K_{\mu \nu \kappa \lambda }$.Comment: 10 page

Utilização do fosfato de tapira em dietas de frangos de corte.

bitstream/item/58576/1/CUsersPiazzonDocuments210.pd

Are we building too many arteriovenous fistulas? A single-center experience

Introduction: Arteriovenous fistula has been associated with improved morbimortality in hemodialysis patients. This has resulted in the “fistula First, catheter last” initiative. Nonetheless, the survival benefit of arteriovenous fistula has been questioned. Methods: We conducted a retrospective observational study of all patients with non-end stage renal disease referred for first vascular access building between January 2014 and December 2015 in our hospital center. Our main goal was to evaluate the clinical impact and burden of building fistula in predialysis patients. Results: During this period, of 178 first arteriovenous accesses placed, 87 patients remained in predialysis and 91 patients started a chronic hemodialysis program. Median follow-up time by a nephrologist was 3.9 (2.5, 9.7) years. The mean age was 65.8±14.7 years, with 50.6% (n=90) of male patients. A higher rate of thrombosis in the predialysis group (26% vs 13%, p=0.037) was observed, but vascular access survival did not differ significantly (55% vs 67%, p=0.12). Mean vascular access placing was higher in the predialysis group (1.4±0.7 vs 1.2±0.4, p=0.006) and less interventions were requested (0.2±0.5 vs 0.3±0.6, p=0.10). Median time from vascular access placement to hemodialysis start was 22 (13, 41) months. At hemodialysis initiation, 10 (10.9%) patients used a central venous catheter; 80 (87.9%) patients an arteriovenous fistula, and one patient a graft. A total of 227 vascular accesses were built; 121 (53.3%) in predialysis vs 106 (46.7%) in incident hemodialysis patients. In a multivariate model, the presence of a functional arteriovenous fistula at hemodialysis start was only associated with a trend to survival benefit (HR 0.38, 95% CI 0.14-1.00, p=0.05). Conclusions: Our results stress the need for an individual approach and for future tools to assess the risk of death and progression to end-stage renal disease, therefore helping reduce the number of unutilized vascular accesses and rising cost of interventions.info:eu-repo/semantics/publishedVersio

Interacting Particles and Strings in Path and Surface Representations

Non-relativistic charged particles and strings coupled with abelian gauge fields are quantized in a geometric representation that generalizes the Loop Representation. We consider three models: the string in self-interaction through a Kalb-Ramond field in four dimensions, the topological interaction of two particles due to a BF term in 2+1 dimensions, and the string-particle interaction mediated by a BF term in 3+1 dimensions. In the first case one finds that a consistent "surface-representation" can be built provided that the coupling constant is quantized. The geometrical setting that arises corresponds to a generalized version of the Faraday's lines picture: quantum states are labeled by the shape of the string, from which emanate "Faraday`s surfaces". In the other models, the topological interaction can also be described by geometrical means. It is shown that the open-path (or open-surface) dependence carried by the wave functional in these models can be eliminated through an unitary transformation, except by a remaining dependence on the boundary of the path (or surface). These feature is closely related to the presence of anomalous statistics in the 2+1 model, and to a generalized "anyonic behavior" of the string in the other case.Comment: RevTeX 4, 28 page