177 research outputs found

    CONSUMO E DIGESTIBILIDADE APARENTE DO FENO DE Andropogon gayanus COLHIDO EM TRÊS IDADES DIFERENTES

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    Este experimento teve como objetivo avaliar o consumo e a digestibilidade aparente da matĂ©ria seca, proteĂ­na bruta, fraçÔes fibrosas, energia e balanço do nitrogĂȘnio do feno de Andropogon gayanus colhido em trĂȘs diferentes idades (56, 84 e 112 dias). O delineamento estatĂ­stico utilizado foi o inteiramente casualizado com trĂȘs tratamentos e seis repetiçÔes. As digestibilidades aparentes da matĂ©ria seca, das fraçÔes fibrosas e da energia bruta foram maiores para os fenos colhidos aos 56 e 84 dias (P0,05). Os valores de consumo e digestibilidade aparente apontam as idades de 56 e 84 dias como as melhores dentre as estudadas para o corte do capim A. gayanus para fenação. Palavras-chave: forragem; ovino; valor nutritivo

    GREEN FORAGE FIBROUS FRACTIONS AND THREE PEARL MILLET GENOTYPES SILAGE [Pennisetum glaucum (L). R. BR.] IN DIFFERENT FERMENTATION PERIODS

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    It was determined the fibrous fraction (NDF, ADF, cellulose, hemicellulose and lignin) in green forage and pearl millet silages (CMS-1, BRS-1501 and BN-2). The genotypes were planted at Embrapa Milho e Sorgo, ensiled in PVC laboratory silos and evaluated after one, three, five, seven, 14, 28 and 56 days. NDF values ranged from 46.96 to 62.43% and ADF from 27.86 to 34.56%. Hemicellulose contents in green forage were significantly lower than in silages after 56 days ensiling. The NDF, ADF, cellulose, hemicellulose and lignin mean values in green forages and silages after 56 days of fermentation were 60.76 and 51.8%, 33.58 and 31.54%, 29.25 and 27.66%, 27.18 and 20.26%; 4.33 and 3.89%, respectively. The NDF and ADF average values found in this work were lower than those reported in other studies. The hemicellulose fraction contributed as an additional subtract source to the fermentation process. BRS-1501 genotype showed the lower NDF and ADF contents

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 60∘60^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law E−γE^{-\gamma} with index Îł=2.70±0.02 (stat)±0.1 (sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25 (stat)−1.2+1.0 (sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file
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