162 research outputs found

    Toxicidade de sementes de fedegoso (Cassia occidentalis L.) para frangos de corte

    Get PDF
    Three experiments were carried out in order to determine toxic levels of Cassia occidentalis seeds added to broiler feed. On the first two experiments 640 one day-old sexed broiler chicks were used. The level of inclusion in starter feed of the first trial were 0; 2; 4 and 6% and the mortality rates obtained were 5.77; 84.62; 100 and 100%, respectively. In the second trial, levels utilized were 0; 0.5; 1 and 2% and the mortality rates were 0; 3.29; 15.73 and 89.47%, respectively. 960 3-day-old sexed chicks were used in the third experiment. In the starter (4 to 31 days of age) and finisher (32 to 52 days) experimental rations the seeds were added at 0; 0.1; 0.2; 0.3; 0.4 and 0.5%. The final body weights were 2.01; 1.95; 1.95; 1.90; 1.77 and 1.58 kg, respectively, being the three highest level groups different from the control. Feed consumption (4.33; 4.32; 4.32; 4.28; 4.08 and 3.80 kg, respectively) and feed conversion (2.15; 2.21; 2.22; 2.25; 2.31 and 2.41, respectively) were significantly different at 0.4 and 0.5% of seed inclusion comparing to the control group. Histologic aspects of birds that were fed with toxic seeds were characterized by a degenerative process found in the heart, liver, pancreas, kidneys, skeletic muscle and intestines. Mortality rates were 2.77; 2.08; 2.08; 0.69; 0.69 and 0%, respectively.Foram realizados três ensaios com o objetivo de se determinar o nível de toxicidade da contaminação de sementes de Cassia occidentalis na alimentação de frangos de corte. Nos dois primeiros ensaios foram utilizadas 640 aves de 1 dia de idade. Os níveis de adição da semente no primeiro ensaio foram, 0; 2; 4 e 6%, obtendo-se 5,77; 84,62; 100 e 100% de mortalidade, respectivamente. No segundo ensaio, os níveis utilizados foram 0; 0,5; 1 e 2%, obtendo-se 0; 3,29; 15,73 e 89,47% de mortalidade, respectivamente. No terceiro ensaio, utilizou-se 960 aves de 3 dias de idade. Adicionou-se a ração inicial (4-31 dias de idade) e final (32-52 dias) sementes moídas de fedegoso aos níveis de 0; 0,1; 0,2; 0,3; 0,4 e 0,5%. O peso médio final das aves foi 2,01; 1,95; 1,95; 1,90; 1,77 e 1,58 kg, respectivamente, observando-se diferença significativa (P < 0,05%) em relação ao controle para 0,3; 0,4 e 0,5% de adição. Os valores médios de consumo (4,33; 4,32; 4,32; 4,28; 4,08 e 3,80 kg, respectivamente) e da conversão alimentar (2,15; 2,21; 2,22; 2,25; 2,31 e 2,41, respectivamente) foram significativamente diferentes (P < 0,05%) para 0,4 e 0,5% de adição das sementes em relação ao grupo controle. O aspecto histológico de órgãos e tecidos das aves que receberam C.occidentalis, sacrificadas no término das fases inicial e final, foi característico de um processo degenerativo observado no coração, fígado, pâncreas, rins, músculo estriado esquelético e intestinos. Os percentuais de mortalidade foram 2,77; 2,08; 2,08; 0,69; 0,69 e 0%, respectivamente

    From M-ary Query to Bit Query: a new strategy for efficient large-scale RFID identification

    Get PDF
    The tag collision avoidance has been viewed as one of the most important research problems in RFID communications and bit tracking technology has been widely embedded in query tree (QT) based algorithms to tackle such challenge. Existing solutions show further opportunity to greatly improve the reading performance because collision queries and empty queries are not fully explored. In this paper, a bit query (BQ) strategy based Mary query tree protocol (BQMT) is presented, which can not only eliminate idle queries but also separate collided tags into many small subsets and make full use of the collided bits. To further optimize the reading performance, a modified dual prefixes matching (MDPM) mechanism is presented to allow multiple tags to respond in the same slot and thus significantly reduce the number of queries. Theoretical analysis and simulations are supplemented to validate the effectiveness of the proposed BQMT and MDPM, which outperform the existing QT-based algorithms. Also, the BQMT and MDPM can be combined to BQMDPM to improve the reading performance in system efficiency, total identification time, communication complexity and average energy cost

    HST/STIS Observations of the Optical Counterpart to GRB 970228

    Get PDF
    We report on observations of the fading optical counterpart of the gamma-ray burst GRB 970228, made on 4~September~1997 using the STIS CCD on the Hubble Space Telescope. The unresolved counterpart is detected at V=28 +/- 0.25, consistent with a continued power-law decline with exponent -1.14 +/- 0.05. No proper motion is detected, in contradiction of some earlier claims. The counterpart is located within, but near the edge of, a faint extended source with diameter ~0."8 and integrated magnitude 25.7 +/- 0.25. Comparison with WFPC2 data taken one month after the initial burst and NTT data taken on March 13 shows no evidence for fading of the extended emission. After adjusting for the probable Galactic extinction in the direction of GRB 970228 of A_v=0.7, we find that the observed nebula is consistent with the sizes of galaxies of comparable magnitude found in the Hubble Deep Field and other deep HST images, and that only 2% of the sky is covered by galaxies of similar or greater surface brightness. Therefore, the extended source observed about GRB 970228 is most likely a galaxy at moderate redshift, and is almost certainly the host of the gamma-ray burst

    Next-to-next-to-leading order prediction for the photon-to-pion transition form factor

    Get PDF
    We evaluate the next-to-next-to-leading order corrections to the hard-scattering amplitude of the photon-to-pion transition form factor. Our approach is based on the predictive power of the conformal operator product expansion, which is valid for a vanishing β\beta-function in the so-called conformal scheme. The Wilson--coefficients appearing in the non-forward kinematics are then entirely determined from those of the polarized deep-inelastic scattering known to next-to-next-to-leading accuracy. We propose different schemes to include explicitly also the conformal symmetry breaking term proportional to the β\beta-function, and discuss numerical predictions calculated in different kinematical regions. It is demonstrated that the photon-to-pion transition form factor can provide a fundamental testing ground for our QCD understanding of exclusive reactions.Comment: 62 pages LaTeX, 2 figures, 9 tables; typos corrected, some references added, to appear in Phys. Rev.

    Abundances of the elements in the solar system

    Full text link
    A review of the abundances and condensation temperatures of the elements and their nuclides in the solar nebula and in chondritic meteorites. Abundances of the elements in some neighboring stars are also discussed.Comment: 42 pages, 11 tables, 8 figures, chapter, In Landolt- B\"ornstein, New Series, Vol. VI/4B, Chap. 4.4, J.E. Tr\"umper (ed.), Berlin, Heidelberg, New York: Springer-Verlag, p. 560-63

    Polarized Parton Distributions in the Nucleon

    Get PDF
    The distribution of the spin of the nucleon among its constituents can be parametrized in the form of polarized parton distribution functions for quarks and gluons. Using all available data on the polarized structure function g1(x,Q2)g_1(x,Q^2), we determine these distributions both at leading and next-to-leading order in perturbation theory. We suggest three different, equally possible scenarios for the polarized gluon distribution, which is found to be only loosely constrained by current experimental data. We examine various possibilities of measuring polarized parton distributions at future experiments.Comment: 18 pages, LATEX, 6 figures available as .uu fil

    Extensive Air Showers from Ultra High Energy Gluinos

    Get PDF
    We study the proposal that the cosmic ray primaries above the Greisen-Zatsepin-Kuzmin (GZK) cutoff are gluino-containing hadrons (g~\tilde g-hadrons). We describe the interaction of g~\tilde g-hadrons with nucleons in the framework of the Gribov-Regge approach using a modified version of the hadronic interaction model QGSJET for the generations of Extensive Air Showers (EAS). There are two mass windows marginally allowed for gluinos: m_{\tilde g}\lsim 3 GeV and 25\lsim m_{\tilde g}\lsim 35 GeV. Gluino-containing hadrons corresponding to the second window produce EAS very different from the observed ones. Light g~\tilde g-hadrons corresponding to the first gluino window produce EAS similar to those initiated by protons, and only future detectors can marginally distinguish them. We propose a beam-dump accelerator experiment to search for g~\tilde g-hadrons in this mass window. We emphasize the importance of this experiment: it can discover (or exclude) the light gluino and its role as a cosmic ray primary at ultra high energies.Comment: 27 pages latex, 13 eps figure

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

    Get PDF
    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

    Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

    Get PDF
    A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM
    corecore