1,164 research outputs found

    Effects of transportation on gastric pH and gastric ulceration in mares

    Get PDF
    Background: Transportation has been suggested as a risk factor for gastric ulceration in horses, but limited evidence supports this assumption. Animals: Twenty-six Standardbred, Thoroughbred, and Warmblood mares from a university teaching herd. Methods: Twelve mares were confined for 12 hours, overnight, in reproductive stocks with indwelling nasogastric tubes (NGTs) to assess pH of gastric fluid (GF). Gastric ulceration was assessed endoscopically before and after confinement. Subsequently, 26 horses were transported for 12 hours, overnight, in 2 consignments. During transportation, GF was aspirated from indwelling NGT placed in the same 12 mares used in the confinement study, and gastric ulceration was assessed endoscopically before and after transportation in all horses. Results: The median pH of GF in confined horses was 1.70-2.49 at each sampling point, and there was no apparent effect on gastric squamous ulcer scores. The median pH of GF from the same 12 horses at corresponding sampling times during transportation was 6.82-7.22. Transportation was associated with increased gastric squamous ulcer scores, particularly in horses fasted for gastroscopy and NGT placement immediately before departure. Gastric emptying appeared delayed after transportation in horses fed before departure. Conclusions and Clinical Importance: Transportation is associated with increased gastric squamous ulceration and with increased pH of GF. These findings may be a consequence of impaired gastric emptying and reflux of alkaline small intestinal content, with factors such as duodenal bile salts and short-chain fatty acids mediating mucosal injury

    Effects of different ACE inhibitor combinations on albuminuria: results of the GUARD study

    Get PDF
    Clinical practice guidelines recommend blockers of the renin-angiotensin system alone or in combination with other agents to reduce blood pressure and albuminuria in patients with type 2 diabetes. Dihydropyridine calcium channel blockers, however, may lower blood pressure but not albuminuria in these patients. Here we tested the hypothesis that combining an ACE inhibitor with either a thiazide diuretic or a calcium channel blocker will cause similar reductions in blood pressure and albuminuria in hypertensive type 2 diabetics. We conducted a double blind randomized controlled trial on 332 hypertensive, albuminuric type 2 diabetic patients treated with benazepril with either amlodipine or hydrochlorothiazide for 1 year. The trial employed a non-inferiority design. Both combinations significantly reduced the urinary albumin to creatinine ratio and sitting blood pressure of the entire cohort. The percentage of patients progressing to overt proteinuria was similar for both groups. When we examined patients who had only microalbuminuria and hypertension we found that a larger percentage of the diuretic and ACE inhibitor normalized their albuminuria. We conclude that initial treatment using benzaepril with a diuretic resulted in a greater reduction in albuminuria compared to the group of ACE inhibitor and calcium channel blocker. In contrast, blood pressure reduction, particularly the diastolic component, favored the combination with amilodipine. The dissociation between reductions in blood pressure and albuminuria may be related to factors other than blood pressure

    On classification of intrinsic localized modes for the Discrete Nonlinear Schr\"{o}dinger Equation

    Full text link
    We consider localized modes (discrete breathers) of the discrete nonlinear Schr\"{o}dinger equation idψndt=ψn+1+ψn12ψn+σψn2ψni\frac{d\psi_n}{dt}=\psi_{n+1}+\psi_{n-1}-2\psi_n+\sigma|\psi_n|^2\psi_n, σ=±1\sigma=\pm1, nZn\in \mathbb{Z}. We study the diversity of the steady-state solutions of the form ψn(t)=eiωtvn\psi_n(t)=e^{i\omega t}v_n and the intervals of the frequency, ω\omega, of their existence. The base for the analysis is provided by the anticontinuous limit (ω\omega negative and large enough) where all the solutions can be coded by the sequences of three symbols "-", "0" and "+". Using dynamical systems approach we show that this coding is valid for ω<ω3.4533\omega<\omega^*\approx -3.4533 and the point ω\omega^* is a point of accumulation of saddle-node bifurcations. Also we study other bifurcations of intrinsic localized modes which take place for ω>ω\omega>\omega^* and give the complete table of them for the solutions with codes consisting of less than four symbols.Comment: 33 pages, 14 figures. To appear in Physica

    Quantum statistical information contained in a semi-classical Fisher--Husimi measure

    Full text link
    We study here the difference between quantum statistical treatments and semi-classical ones, using as the main research tool a semi-classical, shift-invariant Fisher information measure built up with Husimi distributions. Its semi-classical character notwithstanding, this measure also contains information of a purely quantal nature. Such a tool allows us to refine the celebrated Lieb bound for Wehrl entropies and to discover thermodynamic-like relations that involve the degree of delocalization. Fisher-related thermal uncertainty relations are developed and the degree of purity of canonical distributions, regarded as mixed states, is connected to this Fisher measure as well.Comment: 9 pages, 3 figures; chenged conten

    Solar neutrino oscillation parameters after first KamLAND results

    Get PDF
    We analyze the energy spectrum of reactor neutrino events recently observed in the Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND) and combine them with solar and terrestrial neutrino data, in the context of two- and three-family active neutrino oscillations. In the 2-neutrino case, we find that the solution to the solar neutrino problem at large mixing angle (LMA) is basically split into two sub-regions, that we denote as LMA-I and LMA-II. The LMA-I solution, characterized by lower values of the squared neutrino mass gap, is favored by the global data fit. This picture is not significantly modified in the 3-neutrino mixing case. A brief discussion is given about the discrimination of the LMA-I and LMA-II solutions with future KamLAND data. In both the 2- and 3-neutrino cases, we present a detailed analysis of the post-KamLAND bounds on the oscillation parameters.Comment: Revised version. Two figures adde

    LFI 30 and 44 GHz receivers Back-End Modules

    Full text link
    The 30 and 44 GHz Back End Modules (BEM) for the Planck Low Frequency Instrument are broadband receivers (20% relative bandwidth) working at room temperature. The signals coming from the Front End Module are amplified, band pass filtered and finally converted to DC by a detector diode. Each receiver has two identical branches following the differential scheme of the Planck radiometers. The BEM design is based on MMIC Low Noise Amplifiers using GaAs P-HEMT devices, microstrip filters and Schottky diode detectors. Their manufacturing development has included elegant breadboard prototypes and finally qualification and flight model units. Electrical, mechanical and environmental tests were carried out for the characterization and verification of the manufactured BEMs. A description of the 30 and 44 GHz Back End Modules of Planck-LFI radiometers is given, with details of the tests done to determine their electrical and environmental performances. The electrical performances of the 30 and 44 GHz Back End Modules: frequency response, effective bandwidth, equivalent noise temperature, 1/f noise and linearity are presented

    The solar neutrino problem after three hundred days of data at SuperKamiokande

    Get PDF
    We present an updated analysis of the solar neutrino problem in terms of both Mikheyev-Smirnov-Wolfenstein (MSW) and vacuum neutrino oscillations, with the inclusion of the preliminary data collected by the SuperKamiokande experiment during 306.3 days of operation. In particular, the observed energy spectrum of the recoil electrons from 8B neutrino scattering is discussed in detail and is used to constrain the mass-mixing parameter space. It is shown that: 1) the small mixing MSW solution is preferred over the large mixing one; 2) the vacuum oscillation solutions are strongly constrained by the energy spectrum measurement; and 3) the detection of a possible semiannual modulation of the 8B \nu flux due to vacuum oscillations should require at least one more year of operation of SuperKamiokande.Comment: 15 pages (RevTeX) + 8 figures (postscript). Requires epsfig.st

    Constraining neutrino oscillation parameters with current solar and atmospheric data

    Get PDF
    We analyze the impact of recent solar, atmospheric and reactor data in the determination of the neutrino oscillation parameters, taking into account that both the solar nu_e and the atmospheric nu_mu may convert to a mixture of active and sterile neutrinos. We use the most recent global solar neutrino data, including the 1496-day Super-K neutrino data sample, and we investigate in detail the impact of the SNO neutral current, spectral and day/night data by performing also an analysis using only the charged current rate from SNO. The implications of the first 145.1 days of KamLAND data on the determination of the solar neutrino parameters are also discussed in detail. We confirm the clear preference of solar+reactor data for the pure active LMA-MSW solution of the solar neutrino problem, and obtain that the LOW, VAC, SMA and Just-So^2 solutions are disfavored with a Delta_chi^2 = 22, 22, 36, 44, respectively. Furthermore, we find that the global solar data constrains the admixture of a sterile neutrino to be less than 43% at 99% CL. By performing an improved fit of the atmospheric data, we also update the corresponding regions of oscillation parameters. We find that the recent atmospheric Super-K (1489-day) and MACRO data have a strong impact on constraining a sterile component in atmospheric oscillations: if the nu_mu is restricted to the atmospheric mass states only a sterile admixture of 16% is allowed at 99% CL, while a bound of 35% is obtained in the unconstrained case. Pure sterile oscillations are disfavored with a Delta_chi^2 = 34.6 compared to the pure active case.Comment: 28 pages, LaTeX file using RevTEX4, 12 figures and 3 tables included. Improved version including the new KamLAND dat

    Neutrinoless Double Beta Decay in Light of SNO Salt Data

    Get PDF
    In the SNO data from its salt run, probably the most significant result is the consistency with the previous results without assuming the 8B energy spectrum. In addition, they have excluded the maximal mixing at a very high confidence level. This has an important implication on the double beta decay experiments. For the inverted or degenerate mass spectrum, we find |_{ee}| > 0.013 eV at 95% CL, and the next generation experiments can discriminate Majorana and Dirac neutrinos if the inverted or degenerate mass spectrum will be confirmed by the improvements in cosmology, tritium data beta decay, or long-baseline oscillation experiments.Comment: REVTEX4, three figures. Now uses the updated SK atmospheric data rather than naive rescaling. Conclusion unchanged. References adde

    Present and Future Bounds on Non-Standard Neutrino Interactions

    Get PDF
    We consider Non-Standard neutrino Interactions (NSI), described by four-fermion operators of the form (νˉαγνβ)(fˉγf)(\bar{\nu}_{\alpha} \gamma {\nu}_{\beta}) (\bar{f} \gamma f), where ff is an electron or first generation quark. We assume these operators are generated at dimension 8\geq 8, so the related vertices involving charged leptons, obtained by an SU(2) transformation νδeδ\nu_{\delta} \to e_{\delta}, do not appear at tree level. These related vertices necessarily arise at one loop, via WW exchange. We catalogue current constraints from sin2θW\sin^2 \theta_W measurements in neutrino scattering, from atmospheric neutrino observations, from LEP, and from bounds on the related charged lepton operators. We estimate future bounds from comparing KamLAND and solar neutrino data, and from measuring sin2θW\sin^2 \theta_W at the near detector of a neutrino factory. Operators constructed with νμ\nu_\mu and νe\nu_e should not confuse the determination of oscillation parameters at a ν\nufactory, because the processes we consider are more sensitive than oscillations at the far detector. For operators involving ντ\nu_\tau, we estimate similar sensitivities at the near and far detector.Comment: Erratum added at the end of the documen
    corecore