150 resultados para Epididymis tail
Resumo:
Traditional internal combustion engine vehicles are a major contributor to global greenhouse gas emissions and other air pollutants, such as particulate matter and nitrogen oxides. If the tail pipe point emissions could be managed centrally without reducing the commercial and personal user functionalities, then one of the most attractive solutions for achieving a significant reduction of emissions in the transport sector would be the mass deployment of electric vehicles. Though electric vehicle sales are still hindered by battery performance, cost and a few other technological bottlenecks, focused commercialisation and support from government policies are encouraging large scale electric vehicle adoptions. The mass proliferation of plug-in electric vehicles is likely to bring a significant additional electric load onto the grid creating a highly complex operational problem for power system operators. Electric vehicle batteries also have the ability to act as energy storage points on the distribution system. This double charge and storage impact of many uncontrollable small kW loads, as consumers will want maximum flexibility, on a distribution system which was originally not designed for such operations has the potential to be detrimental to grid balancing. Intelligent scheduling methods if established correctly could smoothly integrate electric vehicles onto the grid. Intelligent scheduling methods will help to avoid cycling of large combustion plants, using expensive fossil fuel peaking plant, match renewable generation to electric vehicle charging and not overload the distribution system causing a reduction in power quality. In this paper, a state-of-the-art review of scheduling methods to integrate plug-in electric vehicles are reviewed, examined and categorised based on their computational techniques. Thus, in addition to various existing approaches covering analytical scheduling, conventional optimisation methods (e.g. linear, non-linear mixed integer programming and dynamic programming), and game theory, meta-heuristic algorithms including genetic algorithm and particle swarm optimisation, are all comprehensively surveyed, offering a systematic reference for grid scheduling considering intelligent electric vehicle integration.
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An MS/MS based analytical strategy was followed to solve the complete sequence of two new peptides from frog (Odorrana schmackeri) skin secretion. This involved reduction and alkylation with two different alkylating agents followed by high resolution tandem mass spectrometry. De novo sequencing was achieved by complementary CID and ETD fragmentations of full-length peptides and of selected tryptic fragments. Heavy and light isotope dimethyl labeling assisted with annotation of sequence ion series. The identified primary structures are GCD[I/L]STCATHN[I/L]VNE[I/L]NKFDKSKPSSGGVGPESP-NH2 and SCNLSTCATHNLVNELNKFDKSKPSSGGVGPESF-NH2, i.e. two carboxyamidated 34 residue peptides with an aminoterminal intramolecular ring structure formed by a disulfide bridge between Cys2 and Cys7. Edman degradation analysis of the second peptide positively confirmed the exact sequence, resolving I/L discriminations. Both peptide sequences are novel and share homology with calcitonin, calcitonin gene related peptide (CGRP) and adrenomedullin from other vertebrates. Detailed sequence analysis as well as the 34 residue length of both O. schmackeri peptides, suggest they do not fully qualify as either calcitonins (32 residues) or CGRPs (37 amino acids) and may justify their classification in a novel peptide family within the calcitonin gene related peptide superfamily. Smooth muscle contractility assays with synthetic replicas of the S–S linked peptides on rat tail artery, uterus, bladder and ileum did not reveal myotropic activity.
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We present an extensive optical and near-infrared photometric and spectroscopic campaign of the Type IIP supernova SN 2012aw. The data set densely covers the evolution of SN 2012aw shortly after the explosion through the end of the photospheric phase, with two additional photometric observations collected during the nebular phase, to fit the radioactive tail and estimate the 56Ni mass. Also included in our analysis is the previously published Swift UV data, therefore providing a complete view of the ultraviolet-optical- infrared evolution of the photospheric phase. On the basis of our data set, we estimate all the relevant physical parameters of SN 2012aw with our radiation-hydrodynamics code: envelope mass M env ∼ 20 M ⊙, progenitor radius R ∼ 3 × 1013 cm (∼430 R⊙), explosion energy E ∼ 1.5 foe, and initial 56Ni mass ∼0.06 M⊙. These mass and radius values are reasonably well supported by independent evolutionary models of the progenitor, and may suggest a progenitor mass higher than the observational limit of 16.5 ± 1.5 M ⊙of the Type IIP events.
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We present optical photometry and spectra of the superluminous Type II/IIn supernova (SN) CSS121015:004244+132827 (z = 0.2868) spanning epochs from -30 d (rest frame) to more than 200 d after maximum. CSS121015 is one of the more luminous SNe ever found and one of the best observed. The photometric evolution is characterized by a relatively fast rise to maximum (~40 d in the SN rest frame), and by a linear post-maximum decline. The light curve shows no sign of a break to an exponential tail. A broad Hα is first detected at ~+40 d (rest frame). Narrow, barely resolved Balmer and [O iii] 5007 Å lines, with decreasing strength, are visible along the entire spectral evolution. The spectra are very similar to other superluminous supernovae (SLSNe) with hydrogen in their spectrum, and also to SN 2005gj, sometimes considered Type Ia interacting with H-rich circumstellar medium. The spectra are also similar to a subsample of H-deficient SLSNe. We propose that the properties of CSS121015 are consistent with the interaction of the ejecta with a massive, extended, opaque shell, lost by the progenitor decades before the final explosion, although a magnetar-powered model cannot be excluded. Based on the similarity of CSS121015 with other SLSNe (with and without H), we suggest that the shocked-shell scenario should be seriously considered as a plausible model for both types of SLSN. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
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We present new data for five underluminous Type II-plateau supernovae (SNe IIP), namely SN 1999gn, SN 2002gd, SN 2003Z, SN 2004eg and SN 2006ov. This new sample of lowluminosity SNe IIP (LL SNe IIP) is analysed together with similar objects studied in the past. All of them show a flat light-curve plateau lasting about 100 d, an underluminous late-time exponential tail, intrinsic colours that are unusually red, and spectra showing prominent and narrow P Cygni lines. A velocity of the ejected material below 103 km s-1 is inferred from measurements at the end of the plateau. The 56Ni masses ejected in the explosion are very small (≤10-2 M⊙). We investigate the correlations among 56Ni mass, expansion velocity of the ejecta and absolute magnitude in the middle of the plateau, confirming the main findings of Hamuy, according to which events showing brighter plateau and larger expansion velocities are expected to produce more 56Ni. We propose that these faint objects represent the LL tail of a continuous distribution in parameters space of SNe IIP. The physical properties of the progenitors at the explosion are estimated through the hydrodynamical modelling of the observables for two representative events of this class, namely SN 2005cs and SN 2008in. We find that the majority of LL SNe IIP, and quite possibly all, originate in the core collapse of intermediate-mass stars, in the mass range 10-15 M⊙.
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We assemble a sample of 24 hydrogen-poor superluminous supernovae(SLSNe). Parameterizing the light-curve shape through rise and declinetime-scales shows that the two are highly correlated. Magnetar-poweredmodels can reproduce the correlation, with the diversity in rise anddecline rates driven by the diffusion time-scale. Circumstellarinteraction models can exhibit a similar rise-decline relation, but onlyfor a narrow range of densities, which may be problematic for thesemodels. We find that SLSNe are approximately 3.5 mag brighter and havelight curves three times broader than SNe Ibc, but that the intrinsicshapes are similar. There are a number of SLSNe with particularly broadlight curves, possibly indicating two progenitor channels, butstatistical tests do not cleanly separate two populations. The generalspectral evolution is also presented. Velocities measured from Fe II aresimilar for SLSNe and SNe Ibc, suggesting that diffusion timedifferences are dominated by mass or opacity. Flat velocity evolution inmost SLSNe suggests a dense shell of ejecta. If opacities in SLSNe aresimilar to other SNe Ibc, the average ejected mass is higher by a factor2-3. Assuming κ = 0.1 cm2 g-1, we estimate amean (median) SLSN ejecta mass of 10 M⊙ (6M⊙), with a range of 3-30 M⊙. Doubling theassumed opacity brings the masses closer to normal SNe Ibc, but with ahigh-mass tail. The most probable mechanism for generating SLSNe seemsto be the core collapse of a very massive hydrogen-poor star, forming amillisecond magnetar.
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This study examines the firm size distribution of US banks and credit unions. A truncated lognormal distribution describes the size distribution, measured using assets data, of a large population of small, community-based commercial banks. The size distribution of a smaller but increasingly dominant cohort of large banks, which operate a high-volume low-cost retail banking model, exhibits power-law behaviour. There is a progressive increase in skewness over time, and Zipf’s Law is rejected as a descriptor of the size distribution in the upper tail. By contrast, the asset size distribution of the population of credit unions conforms closely to the lognormal distribution.
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Animal models of bone marrow transplantation (BMT) allow evaluation of new experimental treatment strategies. One potential strategy involves the treatment of donor marrow with ultra-violet B light to allow transplantation across histocompatibility boundaries without an increase in graft rejection or graft-versus-host disease. A major requirement for a new experimental protocol, particularly if it involves manipulation of the donor marrow, is that the manipulated marrow gives rise to long-term multilineage engraftment. DNA based methodologies are now routinely used by many centres to evaluate engraftment and degree of chimaerism post-BMT in humans. We report the adaptation of this methodology to the serial study of engraftment in rodents. Conditions have been defined which allow analysis of serial tail vein samples using PCR of short tandem repeat sequences (STR-PCR). These markers have been used to evaluate the contribution of ultraviolet B treated marrow to engraftment following BMT in rodents without compromising the health of the animals under study. Chimaerism data from sequential tail vein samples and bone marrow from selected sacrificed animals showed excellent correlation, thus confirming the validity of this approach in analysing haemopoietic tissue. Thus the use of this assay may facilitate experimental studies in animal BMT.
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There is increasing interest in developing abattoir-based welfare measures for pigs.The primary aim of this study was to determine the most appropriate place on theslaughter line to conduct assessments of welfare-related lesions, namely apparentaggression-related skin lesions (hereafter referred to as 'skin lesions'), loin bruising andapparent tail biting damage. The study also lent itself to an assessment of theprevalence of these lesions, and the extent to which they were linked with productionparameters. Finishing pigs processed at two abattoirs on the Island of Ireland (n =1950 in abattoir A, and n = 1939 in abattoir B) were used. Data were collected over 6days in each abattoir in July 2014. Lesion scoring took place at two points on theslaughter line: (1) at exsanguination (Slaughter Stage 1 [SS1]), and (2) followingscalding and dehairing of carcasses (Slaughter Stage 2 [SS2]). At both points, eachcarcass was assigned a skin and tail lesion score ranging from 0 (lesion absent) to 3 or4 (severe lesions), respectively. Loin bruising was recorded as present or absent.Differences in the percentage of pigs with observable lesions of each type werecompared between SS1 and SS2 using McNemar/McNemar-Bowker tests. Theassociations between each lesion type, and both cold carcass weight andcondemnations, were examined at batch level using Pearson's correlations. Batch wasdefined as the group of animals with a particular farm identification code on a givenday. The overall percentage of pigs with a visible skin lesion (i.e. score > 0) decreasedbetween SS1 and SS2 (P<0.001). However, the percentage of pigs with a severe skinlesion increased numerically from SS1 to SS2. The percentage of pigs with a visible taillesion and with loin bruising also increased between SS1 and SS2 (P<0.001). Therewas a positive correlation between the percentage of carcasses that were partiallycondemned, and the percentage of pigs with skin lesions, tail lesions and loin bruising(P<0.05). Additionally, as the batch-level frequency of each lesion type increased,average cold carcass weight decreased (P<0.001). These findings suggest that severeskin lesions, tail lesions and loin bruising are more visible on pig carcasses after theyhave been scalded and dehaired, and that this is when abattoir-based lesion scoringshould take place. The high prevalence of all three lesion types, and the links witheconomically important production parameters, suggests more research into identifying key risk factors is warranted.
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The ejected mass distribution of Type Ia supernovae (SNe Ia) directly probes progenitor evolutionary history and explosion mechanisms, with implications for their use as cosmological probes. Although the Chandrasekhar mass is a natural mass scale for the explosion of white dwarfs as SNe Ia, models allowing SNe Ia to explode at other masses have attracted much recent attention. Using an empirical relation between the ejected mass and the light-curve width, we derive ejected masses Mej and 56Ni masses MNi for a sample of 337 SNe Ia with redshifts z <0.7 used in recent cosmological analyses. We use hierarchical Bayesian inference to reconstruct the joint Mej-MNi distribution, accounting for measurement errors. The inferred marginal distribution of Mej has a long tail towards sub-Chandrasekhar masses, but cuts off sharply above 1.4 M⊙. Our results imply that 25-50 per cent of normal SNe Ia are inconsistent with Chandrasekhar-mass explosions, with almost all of these being sub-Chandrasekhar mass; super-Chandrasekhar-mass explosions make up no more than 1 per cent of all spectroscopically normal SNe Ia. We interpret the SN Ia width-luminosity relation as an underlying relation between Mej and MNi, and show that the inferred relation is not naturally explained by the predictions of any single known explosion mechanism.
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Background: Obestatin is a gastrointestinal peptide with established metabolic actions and emerging vascular effects which involve activation of NO signalling. The aim of this study was to investigate effects of a recently-characterised stable analogue, PEGylated obestatin (PEG-OB), in the setting of diet-induced obesity which is associated with both metabolic and vascular dysfunction. Methods: Male Sprague Dawley rats (6 weeks; n=8) were maintained on standard (SD) or high fat (HF) diet (60% fat) for 8 weeks with once-daily injection of either PEG-OB (50nmol/kg/day) or saline from 2 weeks. Results: HF feeding for 8 weeks resulted in marked body weight gain which was not affected by chronic PEG-OB treatment (HF saline, 175.0±12.2; HF PEG-OB, 190.4±6.4g; P=NS). Similarly, blood glucose, as indicated by HbA1c (HF saline, 6.30±0.15; HF PEG-OB, 6.13±0.36%; P=NS) and insulin tolerance (HF saline, 105.2±52.5; HF PEG-OB, 90.3±45.4mmol/L.min; P=NS), were unaltered by PEG-OB. Despite the apparent lack of metabolic effects, chronic PEG-OB treatment markedly attenuated development of HF-induced hypertension (HF saline, 146.5±4.9mmHg; HF PEG-OB, 123.0±9.7mmHg; P<0.01), assessed by tail-cuff plethysmography. Furthermore, organ bath pharmacology in isolated aortic rings, indicated that HF diet-induced endothelial dysfunction was completely prevented by PEG-OB (acetylcholine, EC50: SD saline, 335±113; HF saline, 758±164; HF PEG-OB, 277±85nmol/L; P<0.05). However, contraction to phenylephrine and relaxation to the NO donor, sodium nitroprusside, were unaltered between groups. Conclusions: PEG-OB exerts beneficial effects on hypertension and endothelial function in diabetes independently of metabolic actions suggesting that obestatin signalling may represent a novel therapeutic target to reduce the risk of associated cardiovascular complications.
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Context. The ESA Rosetta spacecraft, currently orbiting around comet 67P/Churyumov-Gerasimenko, has already provided in situ measurements of the dust grain properties from several instruments,particularly OSIRIS and GIADA. We propose adding value to those measurements by combining them with ground-based observations of the dust tail to monitor the overall, time-dependent dust-production rate and size distribution.
Aims. To constrain the dust grain properties, we take Rosetta OSIRIS and GIADA results into account, and combine OSIRIS data during the approach phase (from late April to early June 2014) with a large data set of ground-based images that were acquired with the ESO Very Large Telescope (VLT) from February to November 2014.
Methods. A Monte Carlo dust tail code, which has already been used to characterise the dust environments of several comets and active asteroids, has been applied to retrieve the dust parameters. Key properties of the grains (density, velocity, and size distribution) were obtained from Rosetta observations: these parameters were used as input of the code to considerably reduce the number of free parameters. In this way, the overall dust mass-loss rate and its dependence on the heliocentric distance could be obtained accurately.
Results. The dust parameters derived from the inner coma measurements by OSIRIS and GIADA and from distant imaging using VLT data are consistent, except for the power index of the size-distribution function, which is α = −3, instead of α = −2, for grains smaller than 1 mm. This is possibly linked to the presence of fluffy aggregates in the coma. The onset of cometary activity occurs at approximately 4.3 AU, with a dust production rate of 0.5 kg/s, increasing up to 15 kg/s at 2.9 AU. This implies a dust-to-gas mass ratio varying between 3.8 and 6.5 for the best-fit model when combined with water-production rates from the MIRO experiment.
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Many wildlife studies use chemical analyses to explore spatio-temporal variation in diet, migratory patterns and contaminant exposure. Intrinsic markers are particularly valuable for studying non-breeding marine predators, when direct methods of investigation are rarely feasible. However, any inferences regarding foraging ecology are dependent upon the time scale over which tissues such as feathers are formed. In this study, we validate the use of body feathers for studying non-breeding foraging patterns in a pelagic seabird, the northern fulmar. Analysis of carcasses of successfully breeding adult fulmars indicated that body feathers moulted between September and March, whereas analyses of carcasses and activity patterns suggested that wing feather and tail feather moult occurred during more restricted periods (September to October and September to January, respectively). By randomly sampling relevant body feathers, average values for individual birds were shown to be consistent. We also integrated chemical analyses of body feather with geolocation tracking data to demonstrate that analyses of δ13C and δ15N values successfully assigned 88 % of birds to one of two broad wintering regions used by breeding adult fulmars from a Scottish study colony. These data provide strong support for the use of body feathers as a tool for exploring non-breeding foraging patterns and diet in wide-ranging, pelagic seabirds.
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Transonic tests in linear cascade wind tunnels can suffer
from significant test section boundary interference effects in pitch. A slotted tailboard has been designed and optimised with an in-house Euler numerical method to reduce such ef- fects. Wind tunnel measurements on an overspeed Mach 1.27 discharge from a Rolls-Royce T2 cascade, featuring strong end-wall shock-induced interference, showed a 77% reduction in the flow pitchwise periodicity error with the optimised tail- board, with respect to the baseline open-jet cascade flow. Two-dimensional Euler predictions were also cross-validated against a three-dimensional Reynolds averaged computation, to explore the three-dimensionality of the discharge
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By testing a simple asset pricing model of heterogeneous agents to characterize the power-law behavior of the DAX 30 from 1975 to 2007, we provide supporting evidence on empirical findings that investors and fund managers use combinations of fixed and switching strategies based on fundamental and technical analysis when making investment decisions. By conducting econometric analysis via Monte Carlo simulations, we show that the autocorrelation patterns, the estimates of the power-law decay indices, (FI)GARCH parameters, and tail index of the model match closely the corresponding estimates for the DAX 30. A mechanism analysis based on the calibrated model provides further insights into the explanatory power of heterogeneous agent models.