Los pliegues cutáneos como predictores del porcentaje graso en futbolistas profesionales

El objetivo del presente estudio fue determinar los pliegues cutáneos que mejor predicen el porcentaje de grasa de futbolistas profesionales Peruanos a partir de tres ecuaciones. Para lo cual, se estudiaron 136 futbolistas profesionales evaluándose el peso corporal (kg), la estatura (m) y los pliegues cutáneos (mm) tricipital, subescapular, suprailiaco, abdominal, muslo y pantorrilla. Los resultados fueron analizados a través de la estadística descriptiva de la media aritmética (X) y desviación estándar (DE) y la estadística inferencial de regresión múltiple StepWise (p<0,001). Los resultados señalan que el % de grasa corporal hallado por las tres ecuaciones sugieren que los pliegues cutáneos tricipital, subescapular, suprailiaco y abdominal, explican mejor el % de grasa en relación a los pliegues del muslo y la pantorrilla media.The aim of this study was to determine the best predictors skinfold fat percentage Peruvian professional footballers from three equations. To this end, we studied 136 professional football players evaluated body weight (kg), height (m) and skinfold (mm) triceps, subscapular, suprailiac, abdominal, thigh and calf. The results were analyzed through descriptive statistics of the arithmetic mean (X) and standard deviation (SD) and inferential statistics multiple stepwise regression (p <0.001). The results indicate that the% body fat found by the three equations suggest that the triceps skinfold, subscapular, suprailiac and abdominal best explain the% fat in relation to the folds of the thigh and calf average.Peer Reviewe

2D Fourier Transform Spectroscopy of exciton-polaritons and their interactions

We investigate polariton-polariton interactions in a semiconductor microcavity through two-dimensional Fourier transform (2DFT) spectroscopy. We observe, in addition to the lower-lower and the upper-upper polariton self-interaction, a lower-upper cross-interaction. This appears as separated peaks in the on-diagonal and off-diagonal part of 2DFT spectra. Moreover, we elucidate the role of the polariton dispersion through a fine structure in the 2DFT spectrum. Simulations, based on lower-upper polariton basis Gross-Pitaevskii equations including both self and cross-interactions, result in a 2DFT spectra in qualitative agreement with experiments

Temporally resolved second-order photon correlations of exciton-polariton Bose-Einstein condensate formation

Second-order time correlation measurements with a temporal resolution better than 3 ps were performed on a CdTe microcavity where spontaneous Bose-Einstein condensation is observed. After the laser pulse, the nonresonantly excited thermal polariton population relaxes into a coherent polariton condensate. Photon statistics of the light emitted by the microcavity evidences a clear phase transition from the thermal state to a coherent state, which occurs within 3.2 ps after the onset of stimulated scattering. Following this very fast transition, we show that the emission possesses a very high coherence that persists for more than 100 ps after the build-up of the condensate.Comment: 4 pages, 3 figure

Periodic squeezing in a polariton Josephson junction

The use of a Kerr nonlinearity to generate squeezed light is a well-known way to surpass the quantum noise limit along a given field quadrature. Nevertheless, in the most common regime of weak nonlinearity, a single Kerr resonator is unable to provide the proper interrelation between the field amplitude and squeezing required to induce a sizable deviation from Poissonian statistics. We demonstrate experimentally that weakly coupled bosonic modes allow exploration of the interplay between squeezing and displacement, which can give rise to strong deviations from the Poissonian statistics. In particular, we report on the periodic bunching in a Josephson junction formed by two coupled exciton-polariton modes. Quantum modeling traces the bunching back to the presence of quadrature squeezing. Our results, linking the light statistics to squeezing, are a precursor to the study of nonclassical features in semiconductor microcavities and other weakly nonlinear bosonic systems.Comment: 6 pages, 4 figure

A Discussion on Supersymmetric Cosmic Strings with Gauge-Field Mixing

In this paper, following a stream of investigation on supersymmetric gauge theories with cosmic string solutions, we contemplate the possibility of building up a D-and-F term cosmic string by means of a gauge-field mixing in connection with a U(1) x U(1)'-symmetry. The spontaneous break of both gauge symmetry and supersymmetry are thoroughly analysed and the fermion zero-modes are worked out. The role of the gauge-field mixing parameter is elucidated in connection with the string configuration that comes out. As an application of the model presented here, we propose the possibility that the supersimetric cosmic string yield production of fermionic charge carriers that may eject, at their late stages, particles that subsequently decay to produce cosmic rays of ultra-high energy. In our work, it turns out that massive supersymmetric fermionic partners may be produced for a susy breaking scale in the range 10^{11} to 10^{13} GeV, which is compatible with the phenomenology of a gravitino mass at the TeV scale. We also determine the range of the gauge-field mixing parameter, \alpha, in connection with the mass scales of the present model.Comment: 7 pages, no figures, ReVTex format, to appear in New Journal of Physic

Anderson localisation in steady states of microcavity polaritons

We present an experimental signature of the Anderson localisation of microcavity polaritons, and provide a systematic study of the dependence on disorder strength. We reveal a controllable degree of localisation, as characterised by the inverse-participation ratio, by tuning the positional disorder of arrays of interacting mesas. This constitutes the realisation of disorder-induced localisation in a driven-dissipative system. In addition to being an ideal candidate for investigating localisation in this regime, microcavity polaritons hold promise for low-power, ultra-small devices and their localisation could be used as a resource in quantum memory and quantum information processing.Comment: 7 pages, 3 figure

Soil aggregation under different management systems

Considering that the soil aggregation reflects the interaction of chemical, physical and biological soil factors, the aim of this study was evaluate alterations in aggregation, in an Oxisol under no-tillage (NT) and conventional tillage (CT), since over 20 years, using as reference a native forest soil in natural state. After analysis of the soil profile (cultural profile) in areas under forest management, samples were collected from the layers 0-5, 5-10, 10-20 and 20-40 cm, with six repetitions. These samples were analyzed for the aggregate stability index (ASI), mean weighted diameter (MWD), mean geometric diameter (MGD) in the classes > 8, 8-4, 4-2, 2-1, 1-0.5, 0.5-0.25, and < 0.25 mm, and for physical properties (soil texture, water dispersible clay (WDC), flocculation index (FI) and bulk density (Bd)) and chemical properties (total organic carbon - COT, total nitrogen - N, exchangeable calcium - Ca2+, and pH). The results indicated that more intense soil preparation (M < NT < PC) resulted in a decrease in soil stability, confirmed by all stability indicators analyzed: MWD, MGD, ASI, aggregate class distribution, WDC and FI, indicating the validity of these indicators in aggregation analyses of the studied soil

Crossover from three-dimensional to two-dimensional systems in the nonequilibrium zero-temperature random-field Ising model

We present extensive numerical studies of the crossover from three-dimensional to two-dimensional systems in the nonequilibrium zero-temperature random-field Ising model with metastable dynamics. Bivariate finite-size scaling hypotheses are presented for systems with sizes L °ø L °ø l which explain the size-driven critical crossover from two dimensions (l = const, L→∞) to three dimensions (l ∝ L→∞). A model of effective critical disorder Reffc (l,L) with a unique fitting parameter and no free parameters in the Reffc (l,L→∞) limit is proposed, together with expressions for the scaling of avalanche distributions bringing important implications for related experimental data analysis, especially in the case of thin three-dimensional systems

Cross Feshbach resonance

Feshbach resonance occurs when a pair of free particles is resonantly coupled to a molecular bound state. In the field of ultracold quantum gases, atomic Feshbach resonances became a usual tool for tailoring atomic interactions opening up many new applications in this field. In a semiconductor microcavity, the Feshbach resonance appears when two lower polaritons are coupled to the molecular biexciton state. Here, we demonstrate the existence of a cross Feshbach resonance for which a pair of polaritons, lower together with upper, effectively couples to the biexciton state. This demonstration is a crucial step towards the efficient generation of entangled photon pairs in a semiconductor microcavity. The existence of a Cross Feshbach resonance establishes the condition to convert a pair of upper and lower polaritons via the biexciton state into two lower polaritons, paving the way for the generation of momentum and polarization entangled photons.Comment: 7 pages, 3 figure

Gender-based violence in Public Health: challenges and achievements

Este texto trata da violência contra mulheres (VCM) como objeto científico e prático da Saúde. É uma reflexão teórica crítica concernente a processos históricos que permitem ver tanto as convergências como os afastamentos entre a tomada dessa violência como questão e particularidades do campo da Saúde, produzindo conquistas e desafios atuais em especial para a Saúde Coletiva. O texto debate aspectos interdisciplinares desse objeto científico e suas implicações para a produção do conhecimento e para as ações em saúde. Considerando as distintas culturas científicas e práticas da Saúde e outros campos que já lidam com VCM, mostram-se tensões existentes entre a perspectiva da violência como questão da saúde e como fenômeno sociocultural, ampliadas com o acréscimo da abordagem de gênero. Produzem-se então desafios de diálogo entre esses campos em termos de paradigmas, modelos científicos e linguagens de cada qual; as necessidades de intervenção social em cada campo; e a relação distinta que cada um possui entre conhecimentos e intervenção social. De outro lado, mostram-se como convergências entre esses campos as conquistas relativas aos direitos humanos e sociais e a proposta de saúde integral. Conclui-se com algumas possíveis respostas aos desafios.This text deals with violence against women (VAW) as a scientific and practical object of Health. It is a theoretical and critical reflection related to historical processes that show convergences and distances between the approach of this violence as an issue and the health field particularities, creating contemporary conquests and challenges especially to Public Health. The text debates interdisciplinary aspects of this scientific object and some impacts to the knowledge production and to health actions. Considering the different scientific and practical cultures of Health and other fields that already deal with VAW, existing tensions between health perspective and violence as a socio-cultural phenomenon are showed, becoming critical when added the gender approach. Challenges are then created on dialogs between those fields in terms of: paradigms, scientific models and languages of each one; social intervention needs in every field; and the distinct relation between knowledge and social intervention presented in each field. On the other hand, the conquests related to human and social rights and the proposal of integral health are shown as convergences between these fields. To conclude, some possible answers to the challenges are considered