Anisotropic simplicial minisuperspace model

The computation of the simplicial minisuperspace wavefunction in the case of anisotropic universes with a scalar matter field predicts the existence of a large classical Lorentzian universe like our own at late timesComment: 19 pages, Latex, 6 figure

Simplicial minisuperspace models in the presence of a massive scalar field with arbitrary scalar coupling

We extend previous simplicial minisuperspace models to account for arbitrary scalar coupling \eta R\phi^2.Comment: 24 pages and 9 figures. Accepted for publication by Classical and Quantum Gravit

ANALYSIS OF THE PERFORMANCE OF ABOVE-KNEE AMPUTEES IN CLIMBING STAIRS

INTRODUCTION Although a large investment has been already made in the study of the walking performance of amputees a greater understanding of the capacities of these subjects is still needed. In this context we undertook the present study in order to analyse the performance of above-knee amputees (AKA) in tasks related to locomotion. We studied two groups of individuals, one of able bodied (AB) subjects and a AKA group, perform ing two different tasks, namely, level ground (LG) walking and climbing stairs (CS). METHODS For each individual and for each task three trials were recorded. The CS task corresponded to the. climbing of a staircase of three 16 cm in height steps. The performances were normalised by comparing a complete LG walking cycle and the climbing CS from the first to the second step. These performances were filmed by two video cameras, one located at the side and another at the back of the track. A thirteen segments body model is used to calculate the center of mass (CM). The percent values of the CM co-ordinates relative to the subject's height is calculated along the vertical (Z axis) , the horizontal antero-posterior (Y axis) and the (axis X) normal to the previous ones using a method developed by Enseberg et al. (1992). The sagittal and lateral inclinations of the trunk and the sagittal rotation of the knee are also computed. RESULTS AND DISCUSSIONS The CM for the AKA group performing the LG and CS tasks is located at a lower level (Z), further to the back (Y) and, generally, on the side of the prosthesis . (X) as compared with its location for the AB group performing the same tasks. These results agree with those obtained Engsberg et al. (1992) for the LG task. The CM location along the Z axis is determined fundamentally by the forward flexion of the trunk and, for both groups of subjects, is lower for the CS task than for the LG tasks as a result of the need to place this center on the vertical of the propulsive limb. For both tasks, the CM location along the Y axis is similar for the two groups and only slightly more posterior for the AKA group in result of the larger backwards rotation of the arm opposite to the prosthesis. The CM location along the X is, for the AKA group, always opposite to the prosthetic side as a result of the trunk compensating inclination in that direction. For the AB group, the CM oscillates naturally from side to side of the body sagittal plane. CONCLUSIONS We may conclude from these results that the two tasks correspond to significantly different performances and that the differences are more profound for the AKA group. The use of a staircase to test the performance of AKA subjects is clinically relevant as it brings up some of the most serious problems associated with the quality of adaptation of the prosthesis to the patient. REFERENCES Engsberg, J., K. Tedford & J. Harder (1992). Center of mass location and segment angular orientation of below-knee amputee and able-bodied children during walking. Arch. Phys. Med. Reahabili, 73, 1163-1168

Diluted manganese on the bond-centered site in germanium

The functional properties of Mn-doped Ge depend to large extent on the lattice location of the Mn impurities. Here, we present a lattice location study of implanted diluted Mn by means of electron emission channeling. Surprisingly, in addition to the expected substitutional lattice position, a large fraction of the Mn impurities occupies the bond-centered site. Corroborated by ab initio calculations, the bond-centered Mn is related to Mn-vacancy complexes. These unexpected results call for a reassessment of the theoretical studies on the electrical and magnetic behavior of Mn-doped Ge, hereby including the possible role of Mn-vacancy complexes

Coordinated Multi-Point MIMO Processing for 4G

The concept of cooperative Multiple-Input-Multiple-Output (MIMO), also referred to as network MIMO, or as Coordinated Multi-Point Transmission (CoMP), was standardized in 3GPP Release 11. The goal of CoMP is to improve the coverage of high data rates and cell-edge throughput, and also to increase system throughput. In this paper we analyze only the latter scenario, using system level simulations in accordance with 3GPP guidelines. It is shown that the use of joint coordinated multipoint transmission achieves additional throughput gains. However, the gains depend on the scheduling type. This paper also indicates that the criterion of fairness is an important parameter when the number of users is high

A pesquisa em agricultura familiar no semi-arido: metodos alternativos de diagnostico e validacao de tecnologias.

Abrigando mais da metade dos estabelecimentos rurais de base familiar do pais, o Nordeste brasileiro esta ameacado de ver a maior parte desse imenso potencial de trabalho e producao desaparecer, em funcao de politicas publicas de desenvolvimento ineficazes, em termos de permitir uma efetiva insercao dessas unidades no mercado, de modo especial na regiao semi-arida. A pesquisa agricola compartilha responsabilidade nesse processo, uma vez que nao foi capaz de incorporar as suas acoes uma visao mais abrangente da problematica do agricultor familiar. Essa situacao comeca, contudo a se modificar na regiao. As experiencias de construcao de metodologias multidisciplinares e participativas adaptadas a realidades locais, comecam a se multiplicar, prenunciando a obtencao de resultados mais objetivos pela pesquisa. Tres dessas metodologias, o zoneamento municipal em unidades de desenvolvimento, o diagnostico rapido dos circuitos de comercializacao e transformacao e a validacao de tecnologias atraves dos testes de ajuste, descritas neste trabalho, sao exemplos desse esforco da pesquisa na busca de uma maior objetividade

Interference Suppression consisting of Pre-Distortion Filtering and Beamforming with joint Transmit Diversity

The purpose of the current paper is to combat both the MAI and fading, in the downlink direction. First, we propose a new pre-distortion (PD) filtering technique, which can be used to combat the Multiple Access Interference (MAI), combined the Selective Transmit Diversity (STD) for high data rate transmissions over frequency selective Rayleigh fading channels. The proposed PD scheme considers a RAKE in the receiver. By pre-distorting the signals to be transmitted by the Base Station (BS) with a Minimum Variance (MV) algorithm, the orthogonality between the desired signal and all interfering signals can be improved. With the PD, the increase in performance is achieved with a small increase in power processing at the BS, avoiding any need to increase complexity at the Mobile Station (MS). Second, we consider a combination of the Beamforming (BF) and Transmit Diversity (TD). The performances of space-time transmit diversity (STTD) in combination with STD, beamforming (BF) and beam selective transmit diversity (BSTD), which is a composite scheme of STD and BF, have been studied at the system level using BER as performance index It is shown that the use of the proposed PD filter, alone or combined with the STD tends to achieve a performance improvement over the corresponding schemes without PD. A good alternative scheme for BSTD, BF and STTD+STD is the use of PD filter, which corresponds to a decrease in complexity

Caracterizacao social e economica da videira.

Introdução; Evolução do cultivo da videira; Importância econômica e social da videira na região

Projeto Gavião: impactos (meio período) do desenvolvimento rural - 1998/2001.

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