4,597 research outputs found
Polarisation measurements with a CdTe pixel array detector for Laue hard X-ray focusing telescopes
Polarimetry is an area of high energy astrophysics which is still relatively
unexplored, even though it is recognized that this type of measurement could
drastically increase our knowledge of the physics and geometry of high energy
sources. For this reason, in the context of the design of a Gamma-Ray Imager
based on new hard-X and soft gamma ray focusing optics for the next ESA Cosmic
Vision call for proposals (Cosmic Vision 2015-2025), it is important that this
capability should be implemented in the principal on-board instrumentation. For
the particular case of wide band-pass Laue optics we propose a focal plane
based on a thick pixelated CdTe detector operating with high efficiency between
60-600 keV. The high segmentation of this type of detector (1-2 mm pixel size)
and the good energy resolution (a few keV FWHM at 500 keV) will allow high
sensitivity polarisation measurements (a few % for a 10 mCrab source in 106s)
to be performed. We have evaluated the modulation Q factors and minimum
detectable polarisation through the use of Monte Carlo simulations (based on
the GEANT 4 toolkit) for on and off-axis sources with power law emission
spectra using the point spread function of a Laue lens in a feasible
configuration.Comment: 10 pages, 6 pages. Accepted for publication in Experimental Astronom
Tipologia socioambiental de cidades médias no Brasil: aportes para um desenvolvimento urbano sustentável
The global urbanization of the territories, which is an important ongoing human ecological phenomenon, and whose environmental impacts have local, regional and global levels, has the remarkable property of a sharp growth of small and intermediate cities, in which capacity of planning and management is usually negligible, when they are compared to large cities. This is what takes place in Brazil, where medium-sized cities, those with populations between 100,000 and 500,000 residents are growing faster than large cities from mid-1990. The article aims to chart a typology of medium Brazilian cities, through multivariate statistical analysis. The resulting typology identifies two types of cities, with different social, environmental and management demands. Some of these cities are located in biodiversity hotspots. In parallel, we have compiled statistics on environmental management in place in these cities. Our results demonstrate low effectiveness of environmental management actions in these municipalitiesA CAPES, y al Ministerio de Agricultura, Alimentación y Medio Ambiente del gobierno español, por la financiación al Proyecto Ecología Urbana en Regiones Metropolitanas de Brasil: Paisaje, Calidad de Vida y Desarrollo Humano [Plan Nacional de I+D+i (CSO2009 12689)
Development and evaluation of an HPLC/DAD method for the analysis of phenolic compounds from olive fruits
A new HPLC/DAD methodology for separating nine phenolic compounds is described. This methodology is applied to the definition of qualitative and quantitative profiles of three Portuguese olive fruit cultivars (Cobrançosa, Madural and Verdeal). Two different extraction methods were needed for the complete definition of their profiles, one of them including a Sep-pack C18 cleaning step. The chromatographic separation was achieved using a Spherisorb ODS2 (25.0 × 0.46 cm; 5 μm, particle size) column. The solvent system used was a gradient of water-formic acid (19:1) and methanol, with a flow rate of 0.9 mL/min. The detection limit values for phenolic compounds were between 0.04 and 4.32 μg/mL and the method was precise. As a general rule, the recovery values were high. This technique can also be useful in the discrimination of Portuguese olive fruit cultivar
Phenolic profile of Cydonia oblonga Miller leaves
Cydonia oblonga Miller leaves phenolic compounds were analyzed by reversed-phase HPLC/DAD and HPLC/UV. Qualitative and quantitative analysis of phenolics were carried out in a total of 36
samples of quince leaves from three different geographical origins of Northern (Bragança and
Carrazeda de Ansiães) and Central Portugal (Covilhã) and three collection months (June, August,
and October of 2006). These leaves presented a common phenolic profile composed by nine
compounds: 3-O-, 4-O- and 5-O-caffeoylquinic acids, 3,5-O-dicaffeoylquinic acid, quercetin-3-Ogalactoside,
quercetin-3-O-rutinoside, kaempferol-3-O-glycoside, kaempferol-3-O-glucoside, and
kaempferol-3-O-rutinoside. 5-O-caffeoylquinic acid was the major phenolic compound (36.2%),
followed by quercetin 3-O-rutinoside (21.1%). Quince leaves are characterized by higher relative
contents of kaempferol derivatives than fruits (pulps, peels, and seeds), especially in what concerns
kaempferol-3-O-rutinoside (12.5%). C. oblonga leaves total phenolic content was very high, varying
from 4.9 to 16.5 g/kg dry matter (mean value of 10.3 g/kg dry matter), indicating that these leaves
can be used as a good and cheap source of bioactive constituents. Significantly differences were
observed in 3-O-caffeoylquinic and 3,5-O-dicaffeoylquinic acids contents, according to geographical
provenance and harvesting month, suggesting a possible use of these compounds as geographical
origin and/or maturity markers
Organic acids composition of Cydonia oblonga Miller leaf
Organic acid profiles of 36 Cydonia oblonga Miller leaf samples, from three different geographical origins of northern (Bragança and Carrazeda de Ansiães) and central Portugal (Covilhã), harvested in three collection months (June, August and October of 2006), were determined by HPLC/UV (214 nm). Quince leaves presented a common organic acid profile, composed of six constituents: oxalic, citric, malic, quinic, shikimic and fumaric acids. C. oblonga leaves total organic acid content varied from 1.6 to 25.8 g/kg dry matter (mean value of 10.5 g/kg dry matter). Quinic acid was the major compound (72.2%), followed by citric acid (13.6%).
Significant differences were found in malic and quinic acids relative abundances and total organic acid contents according to collection time, which indicates a possible use of these compounds as maturity markers.
Between June and August seems to be the best period to harvest quince leaves for preparation of decoctions or infusions, since organic acids total content is higher in this season
Phenolic profile and antioxidative properties of the beefsteak fungus Fistulina hepatica
The phenolic composition of the edible beefsteak fungus Fistulina hepatica was determined by HPLC/DAD. The results showed a profile composed by caffeic, p-coumaric and ellagic acids, hyperoside and quercetin. Ellagic acid was the main compound in this species. Beefsteak fungus was also investigated for its capacity to act as a scavenger of DPPH radical and reactive oxygen species (superoxide radical, hydroxyl radical and hypochlorous acid). Good results were obtained against DPPH and superoxide radicals and hypochlorous acid but a prooxidant effect was observed for hydroxyl radical
Effect of the conservation procedure on the contents of phenolic compounds and organic acids in Chanterelle (Cantharellus cibarius) Mushroom
To check the influence of the conservation procedure in the chemical composition of chanterelle mushroom, phenolic compounds and organic acids of samples preserved under four different
conditions (drying, freezing, conservation in olive oil and in vinegar) were determined. Phenolics and
organic acids were analyzed by HPLC-DAD and HPLC-UV, respectively. The results showed that
chanterelle is characterized by the presence of six phenolic compounds (3-, 4-, and 5-O-caffeoylquinic
acid, caffeic acid, p-coumaric acid, and rutin) and five organic acids (citric, ascorbic, malic, shikimic,
and fumaric acids). Samples preserved in olive oil also exhibited hydroxytyrosol, tyrosol, luteolin,
and apigenin, whereas conservation in vinegar led to the detection of hydroxytyrosol, tyrosol, and
tartaric acid in the analyzed samples. The conservation procedures to which chanterelle samples
were subjected seem to affect the qualitative and quantitative phenolics and organic acids profiles
Generating a checking sequence with a minimum number of reset transitions
Given a finite state machine M, a checking sequence is an input sequence that is guaranteed to lead to a failure if the implementation under test is faulty and has no more states than M. There has been much interest in the automated generation of a short checking sequence from a finite state machine. However, such sequences can contain reset transitions whose use can adversely affect both the cost of applying the checking sequence and the effectiveness of the checking sequence. Thus, we sometimes want a checking sequence with a minimum number of reset transitions rather than a shortest checking sequence. This paper describes a new algorithm for generating a checking sequence, based on a distinguishing sequence, that minimises the number of reset transitions used.This work was supported in part by Leverhulme Trust grant number F/00275/D, Testing State Based Systems, Natural Sciences and Engineering Research Council (NSERC) of Canada grant number RGPIN 976, and Engineering and Physical Sciences Research Council grant number GR/R43150, Formal Methods and Testing (FORTEST)
MAXIMUM NUMBER OF REPETITIONS, TOTAL WEIGHT LIFTED AND NEUROMUSCULAR FATIGUE IN INDIVIDUALS WITH DIFFERENT TRAINING BACKGROUNDS
The aim of this study was to evaluate the performance, as well as neuromuscular activity, in a strength task in subjects with different training backgrounds. Participants (n = 26) were divided into three groups according to their training backgrounds (aerobic, strength or mixed) and submitted to three sessions: (1) determination of the maximum oxygen uptake during the incremental treadmill test to exhaustion and familiarization of the evaluation of maximum strength (1RM) for the half squat; (2) 1RM determination; and (3) strength exercise, four sets at 80�0of the 1RM, in which the maximum number of repetitions (MNR), the total weight lifted (TWL), the root mean square (RMS) and median frequency (MF) of the electromyographic (EMG) activity for the second and last repetition were computed. There was an effect of group for MNR, with the aerobic group performing a higher MNR compared to the strength group (P = 0.045), and an effect on MF with a higher value in the second repetition than in the last repetition (P = 0.016). These results demonstrated that individuals with better aerobic fitness were more fatigue resistant than strength trained individuals. The absence of differences in EMG signals indicates that individuals with different training backgrounds have a similar pattern of motor unit recruitment during a resistance exercise performed until failure, and that the greater capacity to perform the MNR probably can be explained by peripheral adaptations
Distinguishing sequences for partially specified FSMs
Distinguishing Sequences (DSs) are used inmany Finite State Machine (FSM) based test techniques. Although Partially Specified FSMs (PSFSMs) generalise FSMs, the computational complexity of constructing Adaptive and Preset DSs (ADSs/PDSs) for PSFSMs has not been addressed. This paper shows that it is possible to check the existence of an ADS in polynomial time but the corresponding problem for PDSs is PSPACE-complete. We also report on the results of experiments with benchmarks and over 8 * 106 PSFSMs. © 2014 Springer International Publishing
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