Non scientific restrictions to poultry production: main global myth and beliefs.

Projeto/Plano de Ação: 11.11.11.111

How a plantar pressure-based, tongue-placed tactile biofeedback modifies postural control mechanisms during quiet standing

The purpose of the present study was to determine the effects of a plantar pressure-based, tongue-placed tactile biofeedback on postural control mechanisms during quiet standing. To this aim, sixteen young healthy adults were asked to stand as immobile as possible with their eyes closed in two conditions of No-biofeedback and Biofeedback. Centre of foot pressure (CoP) displacements, recorded using a force platform, were used to compute the horizontal displacements of the vertical projection the centre of gravity (CoGh) and those of the difference between the CoP and the vertical projection of the CoG (CoP-CoGv). Altogether, the present findings suggest that the main way the plantar pressure-based, tongue-placed tactile biofeedback improves postural control during quiet standing is via both a reduction of the correction thresholds and an increased efficiency of the corrective mechanism involving the CoGh displacements

Inhabiting warm microhabitats and risk-spreading as strategies for survival of a phytophagous insect living in common pastures in the Pyrenees

[EN] The breakdown of the transhumant grazing system in the Spanish Pyrenees has led to a severe decline in the area of pastures. However, in the high mountain zone there are still large areas of species-rich grasslands. The aim of this study was to assess the oviposition preferences of the shrub-feeding Blue-spot hairstreak, Satyrium spini (Denis & SchiffermÃller, 1775), in montane common pastures in the Spanish Pyrenees and recommend a way of managing these grasslands that favours this species. Our study showed that females of S. spini laid their eggs on Dwarf buckthorn (Rhamnus pumila Turra) and Alpine buckthorn (R. alpina L.), which are novel host plant records for Spain. A warm microclimate was of crucial importance for egg-laying. Occupied plants grew mostly at sparsely vegetated grassland sites where there were large patches of bare rocks, stones or gravel. Most egg batches were laid close to the ground and 75% consisted of only one egg. The number of batches per R. pumila plant was higher on east-, southand west-facing slopes than on north-facing slopes. Presence of eggs and the number of egg batches per R. pumila plant were best explained by a long sunshine duration. At high altitudes particularly warm microhabitats seem to be more important for S. spini than at lower altitudes in Central Europe. We assume that the preference for unusually warm microhabitats is explained by the cold climatic conditions near the altitudinal range limit of the species. That most of the eggs were laid singly and not in small batches as in Central Europe might be a risk-spreading strategy to cope with the harsh climatic conditions and the high inter-annual variation in weather conditions in the high mountain zone in the Pyrenees. The best way to maintain open grasslands for S. spini and other thermophilous grassland species in the high mountain zone of the Pyrenees is to use the traditional combination of sheep and cattle grazing.Peer Reviewe

Vibration stabilization for a cantilever magnet prototype at the subnanometer scale

In the future linear colliders, the size of the beams is in the nanometer range, which requires stabilization of the final magnets before the interaction point. In order to guarantee the desired luminosity, an absolute displacement lower than 1/3 of the beam size, above a few hertz, has to be obtained. This paper describes an adapted instrumentation, the developed feedback loops dedicated to the active compensation and an adapted modelling able to simulate the behaviour of the structure. The obtained results at the subnanometer scale at the free end of a cantilever magnet prototype with a combination of the developed active compensation method and a commercial active isolation system are described

Active stabilization studies at the sub-nanometer level for future linear colliders

The next collider which will be able to contribute significantly to the comprehension of matter is a high energy linear collider. The luminosity of this collider will have to be of 1035cm-2s-1, which imposes a vertical beam size of 0,7nm. The relative motion between the last two focusing magnets should not exceed a third of the beam size above 4Hz. Ground motion and acoustic noise can induce vibrations that have to be compensated with active stabilisation. In this paper, we describe the three aspects needed for such a development. We have assessed sensors capable of measuring sub-nanometre displacements, performed numerical calculations using finite element models to get the dynamic response of the structure, and developed a feedback loop for the active stabilisation. Combining the expertise into a mecatronics project made it possible to obtain a displacement RMS at 5Hz of 0.13nm at the free end of our prototype

Spinor Helicity and Dual Conformal Symmetry in Ten Dimensions

The spinor helicity formalism in four dimensions has become a very useful tool both for understanding the structure of amplitudes and also for practical numerical computation of amplitudes. Recently, there has been some discussion of an extension of this formalism to higher dimensions. We describe a particular implementation of the spinor-helicity method in ten dimensions. Using this tool, we study the tree-level S-matrix of ten dimensional super Yang-Mills theory, and prove that the theory enjoys a dual conformal symmetry. Implications for four-dimensional computations are discussed.Comment: 24 pages, 1 figure

Twistors, Harmonics and Holomorphic Chern-Simons

We show that the off-shell N=3 action of N=4 super Yang-Mills can be written as a holomorphic Chern-Simons action whose Dolbeault operator is constructed from a complex-real (CR) structure of harmonic space. We also show that the local space-time operators can be written as a Penrose transform on the coset SU(3)/(U(1) \times U(1)). We observe a strong similarity to ambitwistor space constructions.Comment: 34 pages, 3 figures, v2: replaced with published version, v3: Added referenc

Model and parameter dependence of heavy quark energy loss in a hot and dense medium

Within the framework of the Langevin equation, we study the energy loss of heavy quark due to quasi-elastic multiple scatterings in a quark-gluon plasma created by relativistic heavy-ion collisions. We investigate how the initial configuration of the quark-gluon plasma as well as its properties affect the final state spectra and elliptic flow of D meson and non-photonic electron. We find that both the geometric anisotropy of the initial quark-gluon plasma and the flow profiles of the hydrodynamic medium play important roles in the heavy quark energy loss process and the development of elliptic flow. The relative contribution from charm and bottom quarks is found to affect the transverse momentum dependence of the quenching and flow patterns of heavy flavor decay electron; such influence depends on the interaction strength between heavy quark and the medium.Comment: 16 pages, 7 figure

Active stabilization of a mechanical structure

This article [1] refers to a particular stage of our attempt to reach the stabilization of the linear collider final focus quadrupole. All along this final focus, an absolute displacement has to be lower than the third of nanometre above a few hertz. The presented intermediary step consists in doing active vibrations control of an elemen-tary mechanical structure in cantilever mode which is similar to the final focus. We consider mainly the active compensation and the latest results on a large prototype. Other aspects are also treated such as modelling, active isolation and instrumentation dedicated to the ground motion

Phylogenetic analysis of porcine circovirus type 2 (PCV-2) in fetuses and stillbirth with natural infection.

Projeto: 03.09.00.046