A stereotaxic method for small animals using experimentally determined reference profiles

In bats conventional stereotaxic methods do not yield sufficient positional accuracy to allow reliable recordings and tracer injections in subnuclei of the auditory system. In a newly developed stereotaxic system experimentally measured patterns of skull profile lines are used to define the animal's brain position with an accuracy of ±100 μm. By combining the neurophysiological stereotaxic procedure with a standardization of the neuroanatomical processing of the brains, the location of recordings, stimulations or injections can be readily transformed into brain atlas coordinates. This facilitates the compilation and comparison of data within and among animals. The system is not restricted to use in bats and can be readily adapted to other experimental animals

Vortex ratchet reversal: The role of interstitial vortices

Triangular arrays of Ni nanotriangles embedded in superconducting Nb films exhibit unexpected dynamical vortex effects. Collective pinning with a vortex lattice configuration different from the expected fundamental triangular "Abrikosov state" is found. The vortex motion which prevails against the triangular periodic potential is produced by channelling effects between triangles. Interstitial vortices coexisting with pinned vortices in this asymmetric potential, lead to ratchet reversal, i.e. a DC output voltage which changes sign with the amplitude of an applied alternating drive current. In this landscape, ratchet reversal is always observed at all magnetic fields (all numbers of vortices) and at different temperatures. The ratchet reversal is unambiguously connected to the presence of two locations for the vortices: interstitial and above the artificial pinning sites.Comment: 21 pages, 4 figures, 1 Tabl

Growth-Induced In-Plane Uniaxial Anisotropy in V2_{2}O3_{3}/Ni Films

We report on a strain-induced and temperature dependent uniaxial anisotropy in V$_{2}$O$_{3}$/Ni hybrid thin films, manifested through the interfacial strain and sample microstructure, and its consequences on the angular dependent magnetization reversal. X-ray diffraction and reciprocal space maps identify the in-plane crystalline axes of the V$_{2}$O$_{3}$; atomic force and scanning electron microscopy reveal oriented rips in the film microstructure. Quasi-static magnetometry and dynamic ferromagnetic resonance measurements identify a uniaxial magnetic easy axis along the rips. Comparison with films grown on sapphire without rips shows a combined contribution from strain and microstructure in the V$_{2}$O$_{3}$/Ni films. Magnetization reversal characteristics captured by angular-dependent first order reversal curve measurements indicate a strong domain wall pinning along the direction orthogonal to the rips, inducing an angular-dependent change in the reversal mechanism. The resultant anisotropy is tunable with temperature and is most pronounced at room temperature, which is beneficial for potential device applications

Efeito da Experiência Atlética e de Diferentes Grupos Musculares na Percepção de Força

O objetivo do presente estudo foi verificar se diferentes níveis de sensibilidade e acurácia na percepção de força podem estar relacionados à experiência atlética e verificar se a acurácia depende do tipo de grupo muscular usado durante diferentes tarefas psicofísicas de percepção de força. Os sujeitos atletas (GA) e sedentários (GS) produziram e estimaram magnitudes de força através de: 1. pressionar manualmente um dinamômetro (DM); 2. erguer pesos na posição supino (SU) e 3. empurrar pesos na posição sentada (LP). Os resultados mostraram que GA e GS têm estilos diferentes de percepção de força. GS percebeu magnitudes de pesos mais próximas da escala real usada na tarefa LP. GA mostrou uma super constância em ambas as tarefas SU e LP. Sub constância foi comum para ambos os grupos na tarefa DM. O GA tendeu a superestimar as magnitudes terminais dos pesos levantados nas tarefas SU e LP e demonstrou pouca sensibilidade às mudanças de baixa intensidade

On the use of Purcell factors for plasmon antennas

The Purcell factor is the standard figure of merit for spontaneous emission enhancement in microcavities, that has also been proposed to describe emission enhancements for plasmonic resonances. A comparison is made of quality factor, mode volume and Purcell factor for single and coupled plasmon spheres to exact calculations of emission rates. The paper explains why the Purcell factor is not appropriate for plasmon antennas.Comment: 3 pages, 2 figure

Mental Health Stigma in the Workplace and its Association with Possible Actions of Managers to Prevent Sickness Absence of Employees with Mental Health Problems in the Swedish Private Sector:a Video Vignette Study

Purpose: Mental health problems (MHPs) are subjected to workplace stigma and can deteriorate into common mental disorders (CMDs) and sickness absence (SA). Research has shown that personal stigmatizing attitudes limit managers’ efforts towards employees with MHPs, but knowledge is lacking regarding stigma in social contexts (contextual stigma) and different types of possible preventive actions. This study investigates personal stigmatizing attitudes and three contextual stigma layers (employee, collegial, organizational) and different types of possible actions to prevent SA of employees with MHPs. Method: Survey data of 2769 Swedish managers working in the private sector were analysed. Personal stigmatizing attitudes were measured with the managerial stigma towards employee depression scale and supplemented with four additional items capturing contextual stigma. Managers watched video vignettes and assessed which preventive actions (n = 20) were possible to use in their organization. A sum score was calculated reflecting the ‘number of actions’. Principal component analysis revealed three action types: adapt tasks and setting, involve experts, and social support. A score reflecting the ‘possibilities to implement actions’ was calculated for each type. Multiple linear regression analyses were conducted with the four stigma layers as independent variables for each of the three action variables.Results: Personal stigmatizing attitudes and contextual stigma were significantly associated with both ‘number of actions’ and ‘possibilities for implementing actions’ relating to all action types. Patterns of associations with contextual stigma were significant but varied between the different action types. Conclusion: This study substantiated the role of personal stigmatizing attitudes and contextual stigma in relation to possible actions of managers to prevent SA of employees with MHPs. The results emphasize the role of contextual stigma. Implications for practice and research are discussed.</p

Bioinformatic approaches for the genetic and phenotypic characterization of a Saccharomyces cerevisiae wine yeast collection

The objective of the present study was to compare genetic and phenotypic variation of 103 Saccharomyces cerevisiae strains isolated from winemaking environments. We used bioinformatics approaches to identify genetically similary strains with specific phenotypes and to estimate a strain&#x27;s biotechnological potential. &#xd;&#xa;A S. cerevisiae collection, comprising 440 strains that were obtained from winemaking environments in Portugal has been constituted during the last years. All strains were genetically characterized by a set of eleven highly polymorphic microsatellites and showed unique allelic combinations. Using neural networks, a subset of 103 genetically most diverse strains was chosen for phenotypic analysis, that included growth in synthetic must media at various temperatures, utilization of carbon sources (glucose, ribose, arabinose, xylose, saccharose, galactose, rafinose, maltose, glycerol, potassium acetate and pyruvic acid), growth in ethanol containing media, evaluation of osmotic and oxidative stress resistance, H2S production and utilization of different nitrogen sources. Using supervised data mining approaches we have found that genotype represented with presence/absence of eleven microsatellites relates well with geographical location (performance evaluation using leave-out-out technique resulted in high performance scores; e.g., area under ROC curve was above 0.8 for a number of standard machine learning approaches tested). To find relations between phenotypes and genotypes, we used a two-step approach which first hierarchically clusters the strains according to their phenotype, and then tests if the resulting sub-clusters are identifiable using strain&#x2019;s genetic data. Several groups of strains with similar phenotype profiles and common features in genotype were identified this way, and they are subject to further investigations. &#xd;&#xa;&#xd;&#xa;Financially supported by the programs POCI 2010 (FEDER/FCT, POCTI/AGR/56102/2004) and AGRO (ENOSAFE, N&#xba; 762).&#xd;&#xa

The non-birefringent limit of all linear, skewonless media and its unique light-cone structure

Based on a recent work by Schuller et al., a geometric representation of all skewonless, non-birefringent, linear media is obtained. The derived constitutive law is based on a "core", encoding the optical metric up to a constant. All further corrections are provided by two (anti-)selfdual bivectors, and an "axion". The bivectors are found to vanish if the optical metric has signature (3,1) - that is, if the Fresnel equation is hyperbolic. We propose applications of this result in the context of transformation optics and premetric electrodynamics.Comment: 12 pages, REVTeX; v2: typos; v3: relevant changes in text, reorganization of manuscript; v4: new section added, final version, to appear in Annalen der Physi

Pressure drop non-linearities in material extrusion additive manufacturing: a novel approach for pressure monitoring and numerical modeling

Fused Filament Fabrication is an additive manufacturing technique in which molten thermoplastic polymers are extruded through a nozzle. Therefore, the interplay between the viscoelastic nature of the polymer melt, temperature, printing conditions and nozzle shape may lead to inconsistent extrusion. To improve the extrusion control and optimize the print-head performance, a better understanding of the flow process of the polymer melt both in the nozzle and the liquefier is needed. However, several challenges need to be overcome due to the complexity of gathering experimental data on the melt pressure in the nozzle and the lack of numerical models able to capture the full rheology of the molten polymer. This research introduces an innovative approach for monitoring the pressure within a material extrusion 3D printer's nozzle. This method involves utilizing a pin in direct contact with the molten material, which then transmits the applied force from the material to an externally mounted load cell. The setup provides reliable, repeatable pressure data in steady-state conditions for two nozzle geometries and at different extrusion flows and temperatures. Moreover, the Giesekus model enabled capturing the viscoelastic rheometric features of the melt, and the numerical predictions have been compared with the experimental data. Results show that the numerical model accurately describes the flow conditions in the nozzle and allows the estimation of the behaviour of the melt in the liquefier zone, the area of the print-head where the filament is molten. It could be concluded that the backflow, which is the backward flow of the molten polymer in the gap between the filament and the liquefier towards the cold end, caused significant non-linearities in the total pressure drop measured in the feeders, which were related to normal forces induced by shear in that region