991 resultados para Montes


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Studies of the performance of the CMS drift tube barrel muon system are described, with results based on data collected during the CMS Cosmic Run at Four Tesla. For most of these data, the solenoidal magnet was operated with a central field of 3.8 T. The analysis of data from 246 out of a total of 250 chambers indicates a very good muon reconstruction capability, with a coordinate resolution for a single hit of about 260 μm, and a nearly 100% efficiency for the drift tube cells. The resolution of the track direction measured in the bending plane is about 1.8 mrad, and the efficiency to reconstruct a segment in a single chamber is higher than 99%. The CMS simulation of cosmic rays reproduces well the performance of the barrel muon detector. © 2010 IOP Publishing Ltd and SISSA.

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In October and November 2008, the CMS collaboration conducted a programme of cosmic ray data taking, which has recorded about 270 million events. The Resistive Plate Chamber system, which is part of the CMS muon detection system, was successfully operated in the full barrel. More than 98% of the channels were operational during the exercise with typical detection efficiency of 90%. In this paper, the performance of the detector during these dedicated runs is reported. © 2010 IOP Publishing Ltd and SISSA.

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The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47μm to 243μm. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns. © 2010 IOP Publishing Ltd and SISSA.

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The alignment system for the muon spectrometer of the CMS detector comprises three independent subsystems of optical and analog position sensors. It aligns muon chambers with respect to each other and to the central silicon tracker. System commissioning at full magnetic field began in 2008 during an extended cosmic ray run. The system succeeded in tracking muon detector movements of up to 18 mm and rotations of several milliradians under magnetic forces. Depending on coordinate and subsystem, the system achieved chamber alignment precisions of 140-350 μm and 30-200 μrad, close to the precision requirements of the experiment. Systematic errors on absolute positions are estimated to be 340-590 μm based on comparisons with independent photogrammetry measurements. © 2010 IOP Publishing Ltd and SISSA.

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The CMS detector is designed around a large 4 T superconducting solenoid, enclosed in a 12 000-tonne steel return yoke. A detailed map of the magnetic field is required for the accurate simulation and reconstruction of physics events in the CMS detector, not only in the inner tracking region inside the solenoid but also in the large and complex structure of the steel yoke, which is instrumented with muon chambers. Using a large sample of cosmic muon events collected by CMS in 2008, the field in the steel of the barrel yoke has been determined with a precision of 3 to 8% depending on the location. © 2010 IOP Publishing Ltd and SISSA.

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The performance of muon reconstruction in CMS is evaluated using a large data sample of cosmic-ray muons recorded in 2008. Efficiencies of various high-level trigger, identification, and reconstruction algorithms have been measured for a broad range of muon momenta, and were found to be in good agreement with expectations from Monte Carlo simulation. The relative momentum resolution for muons crossing the barrel part of the detector is better than 1% at 10 GeV/c and is about 8% at 500 GeV/c, the latter being only a factor of two worse than expected with ideal alignment conditions. Muon charge misassignment ranges from less than 0.01% at 10GeV/c to about 1% at 500 GeV/c. © 2010 IOP Publishing Ltd and SISSA.

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The objective of this study was to characterize the diversity of phytophagous and predatory mites on peach cultivars either with or without fungicide treatment, in the city of Presidente Prudente, State of São Paulo, Brazil. In order to evaluate the effect of fungicides, leaf samples were colleted at random from treated and untreated plants of the Tropical, Aurora 1 and Aurora 2 cultivars, from June 2004 to February 2006. From the results obtained it can be concluded that: plants with or without treatment showed high populations of predatory mites, indicating that the treatments were innocuous on the mite populations. A diversified composition of the mite community was observed. The Phytoseiidae family had the highest richness in numbers and species of mites. Euseius citrifolius and E. concordis were the most abundant species. Plants with or without treatment had high abundances of predatory mites, with a predominance of E. citrifolius.

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Coffee is considered the primary host of the Mediterranean fruit fly Ceratitis capitata (Wiedemann). The infestation of C. capitata in the State of São Paulo has reached economic importance in coffee plantations. Although little information about changes caused by the fly on the coffee beverage, it is known that the fruit fly infestation causes rapid change from cherry to raisin stage, causing qualitative damage on the parchment coffee production. The objective of this work was to study the population dynamics and diversity of Tephritidae and Lonchaeidae in coffee cultivars of Icatu Vermelho IAC 4045, Vermelho IAC 99, Novo Mundo 388-17-1, Obatã IAC 1669-20, Icatu Amarelo IAC 2944, grafted on Apoatã (IAC 2258) (Coffea canephora) and Icatu Vermelho IAC 4045 ungrafted and Apoatã (IAC 2258)-grafted with approximately 3 years. The experiment was conducted in Presidente Prudente, São Paulo State, Brazil, from June 2006 to July 2008. The experimental design was a randomized block with four replications in a factorial design (3 years X 6 cultivars). From each plot of 100 plants we randomly collected 250 mature fruits. The samples were taken at 15 day intervals. The population dynamics were evaluated by using one plastic McPhail trap per cultivar. After 26 months a total of 36,932 specimens of C. capitata were trapped in all cultivars, corresponding to 49.27% males and 50.73% females. Approximately 83.3% of the specimens were collected from January to December 2007. The population fluctuation showed population peaks in May, June and July, relative to fruit ripening period. We trapped 21 specimens of A. montei Lima and A. fraterculus (Wied.). The coffee fruits of Presidente Prudente, SP, are infested by the following species of Lonchaeidae: Neosilba pendula (Bezzi), N. zadolicha McAlpine & Steyskal, N. inesperata Strikis & Prado and Neosilba pradoi Strikis & Lerena. Neosilba pendula occurred in all evaluated cultivars and N. inesperata was recoverd only from Icatu Amarelo IAC 2944 and IAC Icatu Vermelho 4045/un-grafted. No Anastrepha specimen was recovered from the fruits. Cultivars did not differ due to tephritid and lonchaeid infestations, but in 2008 the highest infestation by C. capitata occurred in the field.

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