2,845 research outputs found

    Qualidade de carcaça de novilhos terminados com dietas contendo levedura, monensina e associação de ambos aditivos

    Get PDF
    To evaluate the effects of the supplementation of feed additives on carcass quality in beef cattle, 72 Nellore steers (339.5kg, 20-month old) were feedlot finished and fed for 91 days one of the following diets: 1) control with no additives; or added of 2) live yeast culture; 3) monensin; or 4) the association of both additives. After slaughter, renal, pelvic, and inguinal fat and hot carcass weights were recorded and carcass was split into muscle, bone, and trimmable fat. Carcass Longissimus muscle area and subcutaneous fat thickness at the 12th rib were measured and steaks of Longisimus muscle were taken to determine meat color, shear force, drip, and cooking losses. Yeast increased carcass dressing percentage but there were no effects on hot carcass weight, Longissimus area, subcutaneous fat thickness, percentage and weight of retail cut yield and trimmings. Feed additives had no effect on carcass pH, meat color, fat content, shear force, and drip losses. Supplementation of yeast, monensin or the association of both additives had no important effects on carcass traits and on meat quality of feedlot finished steers.Avaliaram-se os efeitos da suplementação de aditivos alimentares sobre a qualidade de carcaça em bovinos de corte. Usaram-se 72 novilhos Nelore com média de peso de 339,5kg e 20 meses de idade, terminados em confinamento e alimentados por 91 dias com uma das quatro dietas: 1) dieta controle sem aditivos, ou com a adição de 2) leveduras vivas, 3) monensina ou 4) associação entre ambos aditivos. Após o abate, os pesos da gordura renal, pélvica e inguinal e da carcaça foram medidos e a carcaça dividida em músculos, ossos e aparas. Foram mensurados a área de olho de lombo e a espessura de gordura subcutânea sobre o músculo Longissimus na região da 12ª costela e foram obtidos bifes para a determinação da cor, força de cisalhamento e perdas por cocção e cozimento da carne. A levedura aumentou o rendimento de carcaça, mas não houve efeito dos tratamentos sobre o peso de carcaça, porção comestível e aparas. Os aditivos não influenciaram o pH da carcaça, a cor, a gordura intramuscular, a força de cisalhamento e as perdas por exsudação da carne. A suplementação, com levedura e com monensina em associação ou separadamente, não teve efeito importante sobre a qualidade da carcaça em novilhos terminados em confinamento.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    DC modulation noise in clustered particulate media

    Get PDF
    Mallinson’s theory of recording media noise is extended to ensembles where the particles have an easy axis distribution or are clustered. The effect of clusters is that there is a critical value of packing fraction at which noise in the demagnetised state switches to a minimum. Comparison is made with measurements of DC modulation noise in double layer MP tape

    Multi-score Learning for Affect Recognition: the Case of Body Postures

    Get PDF
    An important challenge in building automatic affective state recognition systems is establishing the ground truth. When the groundtruth is not available, observers are often used to label training and testing sets. Unfortunately, inter-rater reliability between observers tends to vary from fair to moderate when dealing with naturalistic expressions. Nevertheless, the most common approach used is to label each expression with the most frequent label assigned by the observers to that expression. In this paper, we propose a general pattern recognition framework that takes into account the variability between observers for automatic affect recognition. This leads to what we term a multi-score learning problem in which a single expression is associated with multiple values representing the scores of each available emotion label. We also propose several performance measurements and pattern recognition methods for this framework, and report the experimental results obtained when testing and comparing these methods on two affective posture datasets

    Quinze anos de monitorização das comunidades biológicas do estuário do Tejo no âmbito da construção e funcionamento das ETARs do Portinho da Costa e da Mutela (Concelho de Almada): Experiência adquirida e ensinamentos para futuros casos semelhantes.

    Get PDF
    Desde 2001 que a Câmara Municipal de Almada tem vindo a promover, em colaboração com o MARE, a monitorização ambiental das regiões estuarinas sob influência das ETARs do Portinho da Costa e da Mutela, que vieram substituir efluentes não tratados emitidos sensivelmente nas mesmas regiões. O objetivo deste programa de monitorização consiste em avaliar as principais alterações ocorridas (na maioria dos casos positivas) nos ecossistemas estuarinos dos vários locais, após a entrada em funcionamento de ambas as infraestruturas. Estes 15 anos de estudos das comunidades bentónicas e de peixes locais têm permitido identificar variações nos padrões espácio-temporais destes compartimentos biológicos e identificar quais dessas evoluções podem ser presumivelmente relacionáveis com o funcionamento das infraestruturas e quais derivam provavelmente de flutuações naturais. Nesta comunicação são enunciados os pressupostos do estudo, descritos os delineamentos experimentais e metodologias de tratamento dos dados adotados, apresentados os principais resultados obtidos e discutidas as grandes dificuldades sentidas para cumprir os objetivos estabelecidos. Este conjunto de elementos será analisado numa perspetiva de como a experiência adquirida pode ser útil, no futuro, para casos semelhantes, sobretudo numa ótica da correta identificação dos verdadeiros efeitos infraestruturais e de despiste da influência de outros fatores concorrentes

    Spin-current modulation and square-wave transmission through periodically stubbed electron waveguides

    Full text link
    Ballistic spin transport through waveguides, with symmetric or asymmetric double stubs attached to them periodically, is studied systematically in the presence of a weak spin-orbit coupling that makes the electrons precess. By an appropriate choice of the waveguide length and of the stub parameters injected spin-polarized electrons can be blocked completely and the transmission shows a periodic and nearly square-type behavior, with values 1 and 0, with wide gaps when only one mode is allowed to propagate in the waveguide. A similar behavior is possible for a certain range of the stub parameters even when two-modes can propagate in the waveguide and the conductance is doubled. Such a structure is a good candidate for establishing a realistic spin transistor. A further modulation of the spin current can be achieved by inserting defects in a finite-number stub superlattice. Finite-temperature effects on the spin conductance are also considered.Comment: 19 pages, 8 figure

    Olive phenology as a sensitive indicator of future climatic warming in the Mediterranean

    Get PDF
    Experimental and modelling work suggests a strong dependence of olive flowering date on spring temperatures. Since airborne pollen concentrations reflect the flowering phenology of olive populations within a radius of 50 km, they may be a sensitive regional indicator of climatic warming. We assessed this potential sensitivity with phenology models fitted to flowering dates inferred from maximum airborne pollen data. Of four models tested, a thermal time model gave the best fit for Montpellier, France, and was the most effective at the regional scale, providing reasonable predictions for 10 sites in the western Mediterranean. This model was forced with replicated future temperature simulations for the western Mediterranean from a coupled ocean-atmosphere general circulation model (GCM). The GCM temperatures rose by 4·5 °C between 1990 and 2099 with a 1% per year increase in greenhouse gases, and modelled flowering date advanced at a rate of 6·2 d per °C. The results indicated that this long-term regional trend in phenology might be statistically significant as early as 2030, but with marked spatial variation in magnitude, with the calculated flowering date between the 1990s and 2030s advancing by 3–23 d. Future monitoring of airborne olive pollen may therefore provide an early biological indicator of climatic warming in the Mediterranean

    Spin-polarized transport and Andreev reflection in semiconductor/superconductor hybrid structures

    Full text link
    We show that spin-polarized electron transmission across semiconductor/superconductor (Sm/S) hybrid structures depends sensitively on the degree of spin polarization as well as the strengths of potential and spin-flip scattering at the interface. We demonstrate that increasing the Fermi velocity mismatch in the Sm and S regions can lead to enhanced junction transparency in the presence of spin polarization. We find that the Andreev reflection amplitude at the superconducting gap energy is a robust measure of the spin polarization magnitude, being independent of the strengths of potential and spin-flip scattering and the Fermi velocity of the superconductor.Comment: 4 pages, 2 figure

    Kafirin structure and functionality

    Get PDF
    The structural and functional properties of kafirins are reviewed. Three classes of kafirin: the a, ß and ? forms have been identified at the protein level and one, the d, has been identified only at the gene and transcript levels. All forms show high homology with the equivalent zein proteins. By analogy with the zeins it is believed that the a-kafirins probably have an extended hairpin structure in solution, comprising elements of a-helix, ß-sheet and turns folded back on itself. Kafirins are the most hydrophobic of the prolamins as shown by their solubility, and calculated hydration free energies. The proteins exhibit extensive cross-linking by disulphide bonds and on cooking form indigestible aggregates which are not solubilised by reduction of disulphide bonds. In spite of continuing studies, the reasons for the low digestibility of the protein remain uncertain and there may be several factors involved. Other research has shown that kafirins may have non-food uses and may be used to form films

    Filtering spin with tunnel-coupled electron wave guides

    Full text link
    We show how momentum-resolved tunneling between parallel electron wave guides can be used to observe and exploit lifting of spin degeneracy due to Rashba spin-orbit coupling. A device is proposed that achieves spin filtering without using ferromagnets or the Zeeman effect.Comment: 4 pages, 4 figures, RevTex

    On Aharonov-Casher bound states

    Full text link
    In this work bound states for the Aharonov-Casher problem are considered. According to Hagen's work on the exact equivalence between spin-1/2 Aharonov-Bohm and Aharonov-Casher effects, is known that the E\boldsymbol{\nabla}\cdot\mathbf{E} term cannot be neglected in the Hamiltonian if the spin of particle is considered. This term leads to the existence of a singular potential at the origin. By modeling the problem by boundary conditions at the origin which arises by the self-adjoint extension of the Hamiltonian, we derive for the first time an expression for the bound state energy of the Aharonov-Casher problem. As an application, we consider the Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the expression for the harmonic oscillator energies and compare it with the expression obtained in the case without singularity. At the end, an approach for determination of the self-adjoint extension parameter is given. In our approach, the parameter is obtained essentially in terms of physics of the problem.Comment: 11 pages, matches published versio
    corecore