4,032 research outputs found
Problems in Treating Experimentally Induced Acute Hepatic Failure by Hemoperfusion or Cross Circulation
Acute hepatic failure was induced in rats by galactosamine injection intraperitoneally (1 gm per kg). Twenty-four hours later rats were treated by hemoperfusion (HP) over encapsulated sorbents: cellulose acetate-coated charcoal, polyelectrolyte-coated XAD4, a combination of both, or cross circulation with a healthy donor. Compared with control treatment (prevention of hypoglycemia by glucose infusion), the survival rate was not improved by HP or cross circulation: controls 19% vs. treated animals 0 to 17%. Extension of duration or increased frequency of HP gave the same survival rates. Computer simulation based on zero-order introduction of a possible toxin into a two-compartment model shows that HP up to 5 hr per day is not able to clear the body effectively from the assumed toxin if its partition coefficient exceeds a value of 50
Planetary nebulae detected in the Spitzer Space Telescope GLIMPSE 3D Legacy Survey
Due to interstellar extinction, optical census of Galactic planetary nebulae (PNs) is highly incomplete, and some compact H ii regions might have been mis-classified as PNs. The problem is particularly severe in the Galactic plane where the extinction in the optical is significant and hampers the detections of PNs. Unlike optical observations, infrared (IR) observations are hardly affected by interstellar extinction, and provide a good opportunity to study highly obscured PNs. In this study, we use the data from the Spitzer Legacy Infrared Mid-Plane Survey Extraordinaire 3D (GLIMPSE 3D) to investigate the mid-infrared (MIR) properties of PNs and PN candidates. © 2012 International Astronomical Union.published_or_final_versionThe IAU Symposium No. 283: 'Planetary Nebulae: an Eye to the Future', Puerto de la Cruz, Tenerife, Spain, 25-29 July 2011. In International Astronomical Union Proceedings, 2011, v. 7 n. S283, p. 528-52
Measurements of Gd 152 (p,Îł) Tb 153 and Gd 152 (p,n) Tb 152 reaction cross sections for the astrophysical Îł process
The total cross sections for the Gd152(p,γ)Tb153 and Gd152(p,n)152Tb reactions have been measured by the activation method at effective center-of-mass energies 3.47≤Ec.m.eff≤7.94 MeV and 4.96≤Ec.m.eff≤7.94 MeV, respectively. The targets were prepared by evaporation of 30.6% isotopically enriched Gd152 oxide on aluminum backing foils, and bombarded with proton beams provided by a cyclotron accelerator. The cross sections were deduced from the observed γ-ray activity, which was detected off-line by an HPGe detector in a low background environment. The results are presented and compared with predictions of statistical model calculations. This comparison supports a modified optical proton+Gd152 potential suggested earlier.Peer reviewedFinal Accepted Versio
Light-ion production in the interaction of 96 MeV neutrons with oxygen
Double-differential cross sections for light-ion (p, d, t, He-3 and alpha)
production in oxygen, induced by 96 MeV neutrons are reported. Energy spectra
are measured at eight laboratory angles from 20 degrees to 160 degrees in steps
of 20 degrees. Procedures for data taking and data reduction are presented.
Deduced energy-differential and production cross sections are reported.
Experimental cross sections are compared to theoretical reaction model
calculations and experimental data at lower neutron energies in the literature.
The measured proton data agree reasonably well with the results of the model
calculations, whereas the agreement for the other particles is less convincing.
The measured production cross sections for protons, deuterons, tritons and
alpha particles support the trends suggested by data at lower energies.Comment: 21 pages, 13 figures, submitted to Phys. Rev.
Comparison between two methods of solution of coupled equations for low-energy scattering
Cross sections from low-energy neutron-nucleus scattering have been evaluated
using a coupled channel theory of scattering. Both a coordinate-space and a
momentum-space formalism of that coupled-channel theory are considered.A simple
rotational model of the channel interaction potentials is used to find results
using two relevant codes, ECIS97 and MCAS, so that they may be compared. The
very same model is then used in the MCAS approach to quantify the changes that
occur when allowance is made for effects of the Pauli principle.Comment: 6 pages, 3 figure
Experimental evaluation of the power balance model of speed skating
Prediction of speed skating performance with a power balance model requires assumptions about the kinetics of energy production, skating efficiency, and skating technique. The purpose of this study was to evaluate these parameters during competitive imitations for the purpose of improving model predictions. Elite speed skaters (n = 8) performed races and submaximal efficiency tests. External power output (Po) was calculated from movement analysis and aerodynamic models and ice friction measurements. Aerobic kinetics was calculated from breath-by-breath oxygen uptake (V̇O2). Aerobic power (Paer) was calculated from measured skating efficiency. Anaerobic power (Pan) kinetics was determined by subtracting P aer from Po. We found gross skating efficiency to be 15.8% (1.8%.). In the 1,500-m event, the kinetics of Pan was characterized by a first-order system as Pan = 88 + 556e-0.0494t (in W, where t is time). The rate constant for the increase in Paer was -0.153 s-1, the time delay was 8.7 s, and the peak Paer was 234 W; Paer was equal to 234[1 - e-0.153(t-8.7)] (in W). Skating position changed with preextension knee angle increasing and trunk angle decreasing throughout the event. We concluded the pattern of P aer to be quite similar to that reported during other competitive imitations, with the exception that the increase in Paer was more rapid. The pattern of Pan does not appear to fit an "all-out" pattern, with near zero values during the last portion of the event, as assumed in our previous model (De Koning JJ, de Groot G, and van Ingen Schenau GJ. J Biomech 25: 573-580, 1992). Skating position changed in ways different from those assumed in our previous model. In addition to allowing improved predictions, the results demonstrate the importance of observations in unique subjects to the process of model construction
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Using ghost fronts within STEREO Heliospheric Imager data to infer the evolution in longitudinal structure of a coronal mass ejection
Images of coronal mass ejections (CMEs) from the Heliospheric Imager (HI) instruments on board the STEREO spacecraft frequently contain rich structure. Here, we present analysis of the Earth-directed CME launched on 12 December 2008 in which we intepret the revealed structure as projections of separate discrete sections of the physical boundary of the CME. By comparing the relative position of the outer and inner 'ghost' fronts seen in the STEREO HI1 cameras with the positions of features determined from three CME models we show that the two fronts seen in the images correspond to the expected position of the flank and nose of the CME where the background solar wind is uniform. In contrast, the flank of the CME observed expanding into a structured background solar wind results in the elongation between the two fronts being greater than expected. This is consistent with the CME flank distorting in the presence of a high-speed solar wind stream. Further work is required to consolidate these results. The presence of a shock for this event was ruled out by consideration of the low CME speed and by studying in-situ spacecraft data. The CME flank crossing the Thomson sphere was also ruled out as a cause of the ghost fronts. Ghost fronts could provide information about the longitudinal shape of the CME independent of geometric models. This technique could subsequently be used to improve space weather forecast models through techniques such as data assimilation
Comparing league formats with respect to match importance in Belgian football
Recently, most clubs in the highest Belgian football division have become convinced that the format of their league should be changed. Moreover, the TV station that broadcasts the league is pleading for a more attractive competition. However, the clubs have not been able to agree on a new league format, mainly because they have conflicting interests. In this paper, we compare the current league format, and three other formats that have been considered by the Royal Belgian Football Association. We simulate the course of each of these league formats, based on historical match results. We assume that the attractiveness of a format is determined by the importance of its games; our importance measure for a game is based on the number of teams for which this game can be decisive to reach a given goal. Furthermore, we provide an overview of how each league format aligns with the expectations and interests of each type of club
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