Ultracold mixtures of metastable He and Rb: scattering lengths from ab initio calculations and thermalization measurements

We have investigated the ultracold interspecies scattering properties of metastable triplet He and Rb. We performed state-of-the-art ab initio calculations of the relevant interaction potential, and measured the interspecies elastic cross section for an ultracold mixture of metastable triplet $^4$He and $^{87}$Rb in a quadrupole magnetic trap at a temperature of 0.5 mK. Our combined theoretical and experimental study gives an interspecies scattering length $a_{4+87}=+17^{+1}_{-4}$ $a_0$, which prior to this work was unknown. More general, our work shows the possibility of obtaining accurate scattering lengths using ab initio calculations for a system containing a heavy, many-electron atom, such as Rb.Comment: 11 pages, 11 figures, accepted for publication in Phys. Rev.

GHASP: an H{\alpha} kinematic survey of spiral and irregular galaxies -- IX. The NIR, stellar and baryonic Tully-Fisher relations

We studied, for the first time, the near infrared, stellar and baryonic Tully-Fisher relations for a sample of field galaxies taken from an homogeneous Fabry-Perot sample of galaxies (the GHASP survey). The main advantage of GHASP over other samples is that maximum rotational velocities were estimated from 2D velocity fields, avoiding assumptions about the inclination and position angle of the galaxies. By combining these data with 2MASS photometry, optical colors, HI masses and different mass-to-light ratio estimators, we found a slope of 4.48\pm0.38 and 3.64\pm0.28 for the stellar and baryonic Tully-Fisher relation, respectively. We found that these values do not change significantly when different mass-to-light ratios recipes were used. We also point out, for the first time, that rising rotation curves as well as asymmetric rotation curves show a larger dispersion in the Tully-Fisher relation than flat ones or than symmetric ones. Using the baryonic mass and the optical radius of galaxies, we found that the surface baryonic mass density is almost constant for all the galaxies of this sample. In this study we also emphasize the presence of a break in the NIR Tully-Fisher relation at M(H,K)\sim-20 and we confirm that late-type galaxies present higher total-to-baryonic mass ratios than early-type spirals, suggesting that supernova feedback is actually an important issue in late-type spirals. Due to the well defined sample selection criteria and the homogeneity of the data analysis, the Tully-Fisher relation for GHASP galaxies can be used as a reference for the study of this relation in other environments and at higher redshifts.Comment: 16 pages, 6 figures. Accepted for publication in MNRA

Obesity influence on perceived physical overload during vertical handling loads - A preliminary study

Obesity prevalence is increasing among the Portuguese workforce, similarly to other industrial countries. Obesity seems to negatively affect the individuals’ work capacity. Tasks with vertical handling loads, including lifting and lowering, are very common in occupational contexts. With the aim of studying the possible effect of obesity on workers’ physical overload during vertical handling loads, psychophysical data were collected from a total of 14 participants with different obesity levels (non-obese, high level of obesity and very high level). The participants were asked to go through 6 lifting trials with different occupational conditions and, for each task tested, they reported physical loading by using the Borg’ “Category Ratio-10” (CR-10) scale. The obtained results in this preliminary study are not conclusive about the obesity influence on perceived physical overload during vertical handling loads. Accordingly, this study should be continued, by considering a statistically valid sample and other psychophysical techniques that can complement the CR10 scale results

Mesoscopic circuits with charge discreteness:quantum transmission lines

We propose a quantum Hamiltonian for a transmission line with charge discreteness. The periodic line is composed of an inductance and a capacitance per cell. In every cell the charge operator satisfies a nonlinear equation of motion because of the discreteness of the charge. In the basis of one-energy per site, the spectrum can be calculated explicitly. We consider briefly the incorporation of electrical resistance in the line.Comment: 11 pages. 0 figures. Will be published in Phys.Rev.

Raios gama na sobrevivência de plantas de maracujazeiro amarelo inoculadas com Fusarium oxysporum f sp. Passiflorae.

A murcha de Fusarium ou fusariose ocorre em diversas regiões produtoras de maracujá amarelo e tem ocasionado grandes danos devido à morte das plantas. A mutagênese associada à seleção in vitro utilizando fitotoxinas possibilita a aplicação de uma pressão de seleção sobre um grande número de propágulos e, assim, pode direcionar a seleção dos mutantes específicos. Neste trabalho, foi analisado o efeito de raios gama sobre a sobrevivência de plantas de maracujazeiro amarelo inoculados com F. oxysporum f. sp. passflorae. Brotações foliares provenientes de segmentos caulinares de P. edulis irradiados a 20Gy foram submetidas a dois ciclos de seleção em meio de cultura suplementado com o filltrado da cultura fúngica (40% e 50% de filtrado). As plantas selecionadas foram inoculadas com a suspensão de conídio em casa de vegetação e após, transferidas para o campo em local com histórico da doença. Ao final da etapa de seleção in vitro, sobreviveram 17,05% das plantas irradiadas e nenhuma planta do tratamento testemunha. A inoculação com a suspensão de conídio não resultou em diferenças significativas na sobrevivência das plantas irradiadas e não irradiadas. No entanto, em condições de campo, foi confirmado o efeito da radiação no aumento da sobrevivência das plantas, sendo verificada a sobrevivência de 77,78% das plantas irradiadas e a morte de todas as plantas do tratamento testemunha

Transport properties of one-dimensional Kronig-Penney models with correlated disorder

Transport properties of one-dimensional Kronig-Penney models with binary correlated disorder are analyzed using an approach based on classical Hamiltonian maps. In this method, extended states correspond to bound trajectories in the phase space of a parametrically excited linear oscillator, while the on site-potential of the original model is transformed to an external force. We show that in this representation the two probe conductance takes a simple geometrical form in terms of evolution areas in phase-space. We also analyze the case of a general N-mer model.Comment: 16 pages in Latex, 12 Postscript figures include

Delocalization in Continuous Disordered Systems

Continuous One-dimensional models supporting extended states are studied. These delocalized statesoccur at well defined values of the energy and are consequences of simple statistical correlation rules. We explicitly study alloys of delta-barrier potentials as well as alloys and liquids of quantum well as.The divergence of the localization length is studied and a critical exponent 2/3 is found for the delta-barrier case, whereas for the quantum wells we find an exponent of 2 or 2/3 depending on the well's parameters. These results support the idea that correlations between random scattering sequences break Anderson localization. We further calculate the conductance of disordered superlattices. At the peak transmission the relative fluctuations of the transmission coefficient are vanishing.Comment: 8 page

Isocausal spacetimes may have different causal boundaries

We construct an example which shows that two isocausal spacetimes, in the sense introduced by Garc\'ia-Parrado and Senovilla, may have c-boundaries which are not equal (more precisely, not equivalent, as no bijection between the completions can preserve all the binary relations induced by causality). This example also suggests that isocausality can be useful for the understanding and computation of the c-boundary.Comment: Minor modifications, including the title, which matches now with the published version. 12 pages, 3 figure

Morfologia externa dos adultos de Phthia picta (Drury, 1770) (Hemiptera: coreidae).

O objetivo deste trabalho foi descrever a morfologia externa do macho e da fêmea de Phthia picta (Drry, 1770), uma praga importante do tomateiro no Brasil