565 research outputs found
Bacteria in the Air of Housed Swine Units
Two housed, swine-growing-finishing units were studied for numbers of total bacteria, fecal coliforms, Staphylococcus, and Salmonella in the air. At 30.5 and 122 cm from the floor, total colony-forming particles, as tested, averaged 3.4 x 10) and 1.3 x 105/m3 of air, respectively; whereas fecal coliform counts averaged 24 x 103 and 1.9 x 103/m3 of air, respectively. Only 41% of the organisms growing on Staphylococcus 110 medium tested as Staphylococcus. Of 458 Staphylococcus isolates, 5 were coagulase-positive. No Salmonella were detected in the air of the units tested
Drinking Water Treatment Residuals: A Reveiw of Recent Uses
Coagulants such as alum, [Al2(SO4)3X14H2O], ferric chloride [FeCl3], or ferric sulfate [Fe2(SO4)3] are commonly used to remove particulate and dissolved constituents from water supplies in the production of drinking water. The resulting waste product, called water-treatment residuals (WTR), contains precipitated Al and Fe oxyhydroxides resulting in a strong affinity for anionic species. Recent research has focused on using WTR as cost-effective materials to reduce soluble phosphorus (P) in soils, runoff, and land-applied organic wastes (manures and biosolids). Studies show P adsorption by WTR to be fast and nearly irreversible, suggesting long-term stable immobilization of WTR-bound P. Because excessive WTR application can induce P deficiency in crops, effective application rates and methods remain an area of intense research. Removal of other potential environmental contaminants [ClO4, Se(+IV and +VI), As(+III and +V), Hg] by WTR has been documented, suggesting potential use of WTRs in environmental remediation. While creation of Al plant toxicity and enhanced Al leaching are concerns expressed by researchers, at circumneutral soil pH conditions these effects are minimal. Radioactivity, trace element levels, and enhanced Mn leaching have also been cited as potential problems in WTR usage as a soil supplement. However, these issues can be managed so as not to limit the beneficial use of WTRs in controlling off-site P losses to sensitive water bodies or reducing soil-extractable P concentrations
Background reduction and sensitivity for germanium double beta decay experiments
Germanium detectors have very good capabilities for the investigation of rare
phenomena like the neutrinoless double beta decay. Rejection of the background
entangling the expected signal is one primary goal in this kind of experiments.
Here, the attainable background reduction in the energy region where the
neutrinoless double beta decay signal of 76Ge is expected to appear has been
evaluated for experiments using germanium detectors, taking into consideration
different strategies like the granularity of the detector system, the
segmentation of each individual germanium detector and the application of Pulse
Shape Analysis techniques to discriminate signal from background events.
Detection efficiency to the signal is affected by background rejection
techniques, and therefore it has been estimated for each of the background
rejection scenarios considered. Finally, conditions regarding crystal mass,
radiopurity, exposure to cosmic rays, shielding and rejection capabilities are
discussed with the aim to achieve a background level of 10-3 c keV-1 kg-1 y-1
in the region of interest, which would allow to explore neutrino effective
masses around 40 meV.Comment: 13 pages, 19 figures. Accepted by Astroparticle Physic
Modelling the influence of RKIP on the ERK signalling pathway using the stochastic process algebra PEPA
This paper examines the influence of the Raf Kinase Inhibitor Protein (RKIP) on the Extracellular signal Regulated Kinase (ERK) signalling pathway [5] through modelling in a Markovian process algebra, PEPA [11]. Two models of the system are presented, a reagent-centric view and a pathway-centric view. The models capture functionality at the level of subpathway, rather than at a molecular level. Each model affords a different perspective of the pathway and analysis. We demonstrate the two models to be formally equivalent using the timing-aware bisimulation defined over PEPA models and discuss the biological significance
Paralysis of laboratory rabbits by nymphae of Ixodes rubicundus, Neumann 1904 (Acarina: Ixodidae) and some effects on the life-cycle following feeding under different temperature conditions
Feeding under constant cold conditions resulted in a marginal shortening of feeding period and a major
shortening of the subsequent developmental phase of all stages of Ixodes rubicundus Neumann 1904, the Karoo
paralysis tick. Paralysis occurred in laboratory rabbits when nymphae were fed on them under constant warm,
constant cold and fluctuating ambient winter conditions. This paralysis was found to be dependant on infestation
rate and feeding conditions. Under constant cold conditions paralysis resulted from lower levels of infestation
than under warm or under fluctuating winter conditions. Neurological parameters used in assessing the progression
of the paresis are discussed.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201
Anthropogenic Space Weather
Anthropogenic effects on the space environment started in the late 19th
century and reached their peak in the 1960s when high-altitude nuclear
explosions were carried out by the USA and the Soviet Union. These explosions
created artificial radiation belts near Earth that resulted in major damages to
several satellites. Another, unexpected impact of the high-altitude nuclear
tests was the electromagnetic pulse (EMP) that can have devastating effects
over a large geographic area (as large as the continental United States). Other
anthropogenic impacts on the space environment include chemical release ex-
periments, high-frequency wave heating of the ionosphere and the interaction of
VLF waves with the radiation belts. This paper reviews the fundamental physical
process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure
Spin oscillations in transient diffusion of a spin pulse in n-type semiconductor quantum wells
By studying the time and spatial evolution of a pulse of the spin
polarization in -type semiconductor quantum wells, we highlight the
importance of the off-diagonal spin coherence in spin diffusion and transport.
Spin oscillations and spin polarization reverse along the the direction of spin
diffusion in the absence of the applied magnetic field are predicted from our
investigation.Comment: 5 pages, 4 figures, accepted for publication in PR
Isotopic composition of fragments in multifragmentation of very large nuclear systems: effects of the chemical equilibrium
Studies on the isospin of fragments resulting from the disassembly of highly
excited large thermal-like nuclear emitting sources, formed in the ^{197}Au +
^{197}Au reaction at 35 MeV/nucleon beam energy, are presented. Two different
decay systems (the quasiprojectile formed in midperipheral reactions and the
unique source coming from the incomplete fusion of projectile and target in the
most central collisions) were considered; these emitting sources have the same
initial N/Z ratio and excitation energy (E^* ~= 5--6 MeV/nucleon), but
different size. Their charge yields and isotopic content of the fragments show
different distributions. It is observed that the neutron content of
intermediate mass fragments increases with the size of the source. These
evidences are consistent with chemical equilibrium reached in the systems. This
fact is confirmed by the analysis with the statistical multifragmentation
model.Comment: 9 pages, 4 ps figure
The Kuiper Belt and Other Debris Disks
We discuss the current knowledge of the Solar system, focusing on bodies in
the outer regions, on the information they provide concerning Solar system
formation, and on the possible relationships that may exist between our system
and the debris disks of other stars. Beyond the domains of the Terrestrial and
giant planets, the comets in the Kuiper belt and the Oort cloud preserve some
of our most pristine materials. The Kuiper belt, in particular, is a
collisional dust source and a scientific bridge to the dusty "debris disks"
observed around many nearby main-sequence stars. Study of the Solar system
provides a level of detail that we cannot discern in the distant disks while
observations of the disks may help to set the Solar system in proper context.Comment: 50 pages, 25 Figures. To appear in conference proceedings book
"Astrophysics in the Next Decade
Identification of cardiac MRI thresholds for risk stratification in pulmonary arterial hypertension
Rationale: Pulmonary arterial hypertension (PAH) is a life-shortening condition. The European Society of Cardiology and European Respiratory Society and the REVEAL (North American Registry to Evaluate Early and Long-Term PAH Disease Management) risk score calculator (REVEAL 2.0) identify thresholds to predict 1-year mortality.
Objectives: This study evaluates whether cardiac magnetic resonance imaging (MRI) thresholds can be identified and used to aid risk stratification and facilitate decision-making.
Methods: Consecutive patients with PAH (n = 438) undergoing cardiac MRI were identified from the ASPIRE (Assessing the Spectrum of Pulmonary Hypertension Identified at a Referral Center) MRI database. Thresholds were identified from a discovery cohort and evaluated in a test cohort.
Measurements and Main Results: A percentage-predicted right ventricular end-systolic volume index threshold of 227% or a left ventricular end-diastolic volume index of 58 ml/m2 identified patients at low (10%) risk of 1-year mortality. These metrics respectively identified 63% and 34% of patients as low risk. Right ventricular ejection fraction >54%, 37–54%, and <37% identified 21%, 43%, and 36% of patients at low, intermediate, and high risk, respectively, of 1-year mortality. At follow-up cardiac MRI, patients who improved to or were maintained in a low-risk group had a 1-year mortality <5%. Percentage-predicted right ventricular end-systolic volume index independently predicted outcome and, when used in conjunction with the REVEAL 2.0 risk score calculator or a modified French Pulmonary Hypertension Registry approach, improved risk stratification for 1-year mortality.
Conclusions: Cardiac MRI can be used to risk stratify patients with PAH using a threshold approach. Percentage-predicted right ventricular end-systolic volume index can identify a high percentage of patients at low-risk of 1-year mortality and, when used in conjunction with current risk stratification approaches, can improve risk stratification. This study supports further evaluation of cardiac MRI in risk stratification in PAH
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