Differences in receptivity to gastrointestinal infections with nematodes in dairy ewes: Influence of age and of the level of milk production

Resistance to anthelmintics in populations of gastrointestinal nematodes is a major concern in small ruminants. One solution to limit the spread of anthelmintic resistance is to apply treatments selectively by targeting the most susceptible animals within a flock. In dairy goats, previous studies have shown that, within a flock, goats in first lactation and those with high level of milk production were highly receptive to nematode infections. These results provided the rationale for targeted treatments. In dairy ewes, such epidemiological information on possible factors modulating the susceptibility to parasitism were still lacking. The objective of the current study was therefore to examine differences in the level of parasite infection and in the pathophysiological consequences in dairy ewes, depending on the age or on the level of milk production. In three farms, parasite egg excretion, and the serum concentrations of pepsinogen and inorganic phosphate were compared on one hand between primiparous and multiparous ewes; on the other hand, between ewes with the highest and the lowest level of milk production, within a cohort of 3–5-year old animals. Overall, the results did not indicate significant differences for both either the parasitological or pathophysiological measurements depending on the level of milk production. In contrast, significant differences were found according to age, indicating higher levels of infections in the primiparous ewes than in the multiparous ones and suggesting that this category of animals represents a particular parasitic risk within a flock

An organisational model for simplifying the complexity of managing software project

The project success depends to a large degree on communication and coordination among team members. But project management systems and models do not support cooperative group work. Their basic philosophy is rather hierarchical and centralistic. It is the intention of this paper to present an Organisational Model for simplifying the complexity of managing software project, both at software project modelling aspect and the aspect of communication and coordination among project team members. In particular, it focuses on the following points: an activity is the main component of project management, the constraints between activities and resources must be established. A role defines a group of duties and responsibilities. The activity related communication proceeds by the exchange of products between roles. While the constraints coordinate the products flow between roles. The benefit of the practical use of the model is to reduce the coordination effort required of project team members, and thus to increase the productivity in software development project

Geometric shape of invariant manifolds for a class of stochastic partial differential equations

Invariant manifolds play an important role in the study of the qualitative dynamical behaviors for nonlinear stochastic partial differential equations. However, the geometric shape of these manifolds is largely unclear. The purpose of the present paper is to try to describe the geometric shape of invariant manifolds for a class of stochastic partial differential equations with multiplicative white noises. The local geometric shape of invariant manifolds is approximated, which holds with significant likelihood. Furthermore, the result is compared with that for the corresponding deterministic partial differential equations

Environmental assessment of humic acid coated magnetic materials used as catalyst in photo-fenton processes

Persistent organic pollutants have been increasingly detected in natural waters, and this represents a real challenge to the quality of this resource. To remove these species, advanced treatment technologies are required. Among these technologies, Fenton-like and photo-Fenton-like processes have been investigated for the removal of pollutants from water. Delicate aspects of photo-Fenton processes are that light-driven processes are energy intensive and require a fair amount of chemical inputs, which strongly affects their overall environmental burdens. At present, aside from determining the efficiency of the processes to remove pollutants of a particular technology, it becomes fundamental to assess also the environmental sustainability of the overall process. In this work, the methodology of the life cycle assessment (LCA) was applied to identify the hotspots of using magnetite particles covered with humic acid (Fe3O4/HA) as a heterogeneous photo-Fenton catalyst for water remediation. The sustainability of the overall process was considered, and a comparative LCA study was performed between H2O2 and persulfate activation at different pH. The addition of humic substances to the particles allows the effectiveness of the catalyst to improve without increasing the environmental impacts; these processes are strongly correlated with energy consumption and therefore with the efficiency of the process. For this reason, working at acidic pH allows us to contain the impacts

The Reddest DR3 SDSS/XMM Quasars

We have cross-correlated the SDSS DR3 Schneider et al. (2005) quasar catalog with the XMM-Newton archive. Color and redshift selections (g - r > 0.5 and 0.9 z < 2.1) result in a sample of 17 red, moderate redshift quasars. The redshift selection minimizes possible contamination due to host galaxy emission and Lyalpha forest absorption. Both optical and X-ray information are required to distinguish between the two likely remaining causes of the red colors: 1) dust-reddening and 2) an intrinsically red continuum. We find that 7 of 17 quasars can be classified as probable `intrinsically red' objects. These 7 quasars have unusually broad MgII emission lines (=10,500 km s^{-1}), moderately flat, but unabsorbed X-ray spectra =1.66+/-0.08), and low accretion rates (mdot/mdot_{Edd}} ~ 0.01). We suggest low accretion rates as a possible physical explanation for quasars with intrinsically red optical continua. We find that 8 of 17 quasars can be classified as dust-reddened. Three of these have upper-limits on the absorption column from X-ray spectral fits of N_H = 3-13 x 10^{22} cm^2, while the other five quasars must be absorbed by at least N_H = 10^{23} cm^2 in order to be consistent with a comparably selected alpha_{ox}-l_{uv} distribution. Two objects in the sample are unclassified.Comment: 20 pages, 12 figures, Accepted for publication in Ap

New Improved Photometric Redshifts of Galaxies in the HDF

We report new improved photometric redshifts of 1048 galaxies in the Hubble Deep Field (HDF). A standard chi^2 minimizing method is applied to seven-color UBVIJHK photometry by Fernandez-Soto, Lanzetta, & Yahil (1999). We use 187 template SEDs representing a wide variety of morphology and age of observed galaxies based on a population synthesis model by Kodama & Arimoto (1997). We introduce two new recipes. First, the amount of the internal absorption is changed as a free parameter in the range of E(B-V)=0.0 to 0.5 with an interval of 0.1. Second, the absorption due to intergalactic HI clouds is also changed by a factor of 0.5, 1.0, and 1.5 around the opacity given by Madau (1995). The total number of template SEDs is thus 187x6x3=3,366, except for the redshift grid. The dispersion sigma_z of our photometric redshifts with respect to spectroscopic redshifts is sigma_z=0.08 and 0.24 for z2, respectively, which are smaller than the corresponding values (sigma_z=0.09 and 0.45) by Fernandez-Soto et al. Improvement is significant, especially in z>2. This is due to smaller systematic errors which are largely reduced mainly by including three opacities due to intergalactic HI clouds. We discuss redshift distribution N(z) and cosmic star formation rate based on our new photometric redshifts.Comment: 24 pages including 16 eps figures; accepted for publication in Ap

Exploratory Study of the X-Ray Properties of Quasars With Intrinsic Narrow Absorption Lines

We have used archival Chandra and XMM-Newton observations of quasars hosting intrinsic narrow UV absorption lines (intrinsic NALs) to carry out an exploratory survey of their X-ray properties. Our sample consists of three intrinsic-NAL quasars and one "mini-BAL" quasar, plus four quasars without intrinsic absorption lines for comparison. These were drawn in a systematic manner from an optical/UV-selected sample. The X-ray properties of intrinsic-NAL quasars are indistinguishable from those of "normal" quasars. We do not find any excess absorption in quasars with intrinsic NALs, with upper limits of a few times 10^22 cm^-2. We compare the X-ray and UV properties of our sample quasars by plotting the equivalent width and blueshift velocity of the intrinsic NALs and the X-ray spectral index against the "optical-to-X-ray" slope, alpha-ox. When BAL quasars and other AGNs with intrinsic NALs are included, the plots suggest that intrinsic-NAL quasars form an extension of the BAL sequences and tend to bridge the gap between BAL and "normal" quasars. Observations of larger samples of intrinsic-NAL quasars are needed to verify these conclusions. We also test two competing scenarios for the location of the NAL gas in an accretion-disk wind. Our results strongly support a location of the NAL gas at high latitudes above the disk, closer to the disk axis than the dense BAL wind. We detect excess X-ray absorption only in Q0014+8118, which does not host intrinsic NALs. The absorbing medium very likely corresponds to an intervening system at z=1.1, which also produces strong absorption lines in the rest-frame UV spectrum of this quasar. In the appendix we discuss the connection between UV and X-ray attenuation and its effect on alpha-ox.Comment: Accepted by the Astrophysical Journa

The UCSD HIRES/KeckI Damped Lya Abundance Database: II. The Implications

We present a comprehensive analysis of the damped Lya abundance database presented in the first paper of this series. This database provides a homogeneous set of abundance measurements for many elements including Si, Cr, Ni, Zn, Fe, Al, S, Co, O, and Ar from 38 damped Lya systems with z > 1.5. With little exception, these damped Llya systems exhibit very similar relative abundances. There is no significant correlation in X/Fe with [Fe/H] metallicity and the dispersion in X/Fe is small at all metallicity. We search the database for trends indicative of dust depletion and in a few cases find strong evidence. Specifically, we identify a correlation between [Si/Ti] and [Zn/Fe] which is unambiguous evidence for depletion. We present a discussion on the nucleosynthetic history of the damped Lya systems by focusing on abundance patterns which are minimally affected by dust depletion. We find [Si/Fe] -> +0.25 dex as [Zn/Fe] -> 0 and that the [Si/Fe] values exhibit a plateau of ~+0.3 dex at [Si/H] < -1.5 dex. Together these trends indicate significant alpha-enrichment in the damped Lya systems at low metallicity, an interpretation further supported by the observed O/Fe, S/Fe and Ar/Fe ratios. We also discuss Fe-peak nucleosynthesis and the odd-even effect. To assess the impact of dust obscuration, we present estimates of the dust-to-gas ratios for the damped Lya sightlines and crudely calculate dust extinction corrections. The distribution of extinction corrections suggests the effects of dust obscuration are minimal and that the population of 'missing' damped systems has physical characteristics similar to the observed sample. We update our investigation on the chemical evolution of the early universe in neutral gas. [significantly abridged]Comment: 29 pages, 26 figures. Uses emulateapj.sty. Accepted to ApJ: Oct 15, 200