2,091 research outputs found

    Blood Sampling from the Tail Vein, in Comparison with Two Other Techniques, Causes Less Stress to Mice

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    It is important to use the optimal method for repeated blood sampling to ensure minimal stress to mice,  and also to provide better pharmacokinetic and pharmacodynamic data. The aim of the present study was  to compare the impact of blood sampling methods on corticosterone and adrenocorticotropic hormone  (ACTH) levels in mice. Hsdwin:NMRI mice were divided into four sampling groups: control group (I), vena facialis (II), tail vein  (III) and saphenous vein (IV). The first blood samples, obtained from vena facialis, tail or saphenous vein  of conscious mice, were taken at time point 0. The second blood sample was taken by decapitation from  groups II-IV with isoflurane anaesthesia at time point 20 min. The control group animals were anesthetized  and decapitated at 20 min time point. Corticosterone levels in plasma were analyzed at time point 0 and 20  min, and ACTH at time point 20 min. Saphenous bled mice, in comparison with vena facialis and tail vein sampled mice, indicated statistically  significant greater (P < 0.05) level of corticosterone at sampling point (0 min). Rising levels of corticosterone  in all groups differed statistically (P < 0.05) from the control group level, indicating that all tested bleeding  methods were stressful to the experimental animals. However, the tail vein bleeding method stressed  statistically significantly (P < 0.05) less in comparison with vena facialis and saphenous vein bleeding.  At time point 20 min, only saphenous vein bled mice showed statistically significant greater (P < 0.05)  blood levels of ACTH compared to tail vein bled mice. Conditions in sampling and rising levels of corticosterone and/or ACTH level did not show direct correlation.  In conclusion the results suggest that the tail bleeding method accomplished least stress to mice and next  less vena facialis bleeding. Blood collection technique from the saphenous vein was the most stressful to  the experimental animals.

    Q_EC values of the Superallowed beta-Emitters 10-C, 34-Ar, 38-Ca and 46-V

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    The Q_EC values of the superallowed beta+ emitters 10-C, 34-Ar, 38-Ca and 46-V have been measured with a Penning-trap mass spectrometer to be 3648.12(8), 6061.83(8), 6612.12(7) and 7052.44(10) keV, respectively. All four values are substantially improved in precision over previous results.Comment: 9 pages, 7 figures, 5 table

    Supergravity origin of the MSSM inflation

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    We consider the supergravity origin of the recently proposed MSSM inflationary model, which relies on the existence of a saddle point along a dimension six flat direction. We derive the conditions that the Kahler potential has to satisfy for the saddle point to exist irrespective of the hidden sector vevs. We show that these conditions are satisfied by a simple class of Kahler potentials, which we find to have a similar form as in various string theory compactifications. For these potentials, slow roll MSSM inflation requires no fine tuning of the soft supersymmetry breaking parameters.Comment: v3: 10 pages, no figures; version accepted for publication. Typos correcte

    Isomeric states close to doubly magic 132^{132}Sn studied with JYFLTRAP

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    The double Penning trap mass spectrometer JYFLTRAP has been employed to measure masses and excitation energies for 11/2−11/2^- isomers in 121^{121}Cd, 123^{123}Cd, 125^{125}Cd and 133^{133}Te, for 1/2−1/2^- isomers in 129^{129}In and 131^{131}In, and for 7−7^- isomers in 130^{130}Sn and 134^{134}Sb. These first direct mass measurements of the Cd and In isomers reveal deviations to the excitation energies based on results from beta-decay experiments and yield new information on neutron- and proton-hole states close to 132^{132}Sn. A new excitation energy of 144(4) keV has been determined for 123^{123}Cdm^m. A good agreement with the precisely known excitation energies of 121^{121}Cdm^m, 130^{130}Snm^m, and 134^{134}Sbm^m has been found.Comment: 10 pages, 6 figures, submitted to Phys. Rev.

    Dialogue based interfaces for universal access.

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    Conversation provides an excellent means of communication for almost all people. Consequently, a conversational interface is an excellent mechanism for allowing people to interact with systems. Conversational systems are an active research area, but a wide range of systems can be developed with current technology. More sophisticated interfaces can take considerable effort, but simple interfaces can be developed quite rapidly. This paper gives an introduction to the current state of the art of conversational systems and interfaces. It describes a methodology for developing conversational interfaces and gives an example of an interface for a state benefits web site. The paper discusses how this interface could improve access for a wide range of people, and how further development of this interface would allow a larger range of people to use the system and give them more functionality

    Depth and intensity of the sulfate-methane transition zone control sedimentary molybdenum and uranium sequestration in a eutrophic low-salinity setting

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    Molybdenum (Mo) and uranium (U) contents in sedimentary archives are often used to reconstruct past changes in seafloor oxygenation. However, their sequestration processes are as yet poorly constrained in low-salinity coastal waters, which often suffer from anthropogenic eutrophication but only mild oxygen depletion. Due to the consequent lack of robust long-term paleo-redox reconstructions in such settings often characterized by a shallow front of dissolved sulfide accumulation within the sediment pore waters, inadequate understanding of the long-term drivers behind oxygen loss impedes cost-effective mitigation of this environmental problem. Here, we investigate the mechanisms of Mo and U sequestration in an oxic, low-salinity coastal setting in the northern Baltic Sea where anthropogenic eutrophication over the 20th century has resulted in formation of a shallow sulfate-methane transition zone (SMTZ) in the sediment column of this brackish-water basin. Our results demonstrate remarkably similar patterns for authigenic Mo and U sequestration, whereby the depth and intensity of the SMTZ exerts a first-order control on their solid-phase uptake. Sequential extraction analysis suggests that a large part of the authigenic Mo pool is hosted by refractory Fe-S phases such as pyrite and nanoscale FeMoS4, implying that the Fe-sulfide pathway is the dominating process of authigenic Mo scavenging. However, we also observe a pool of extremely labile Mo deep within the SMTZ, which might record an intermediate phase in authigenic Mo sequestration and/or partial switch to the organic matter (OM) pathway at low dissolved Fe levels. Authigenic U resides in acid-extractable and refractory phases, likely reflecting uptake into poorly crystalline monomeric U(IV) and crystalline uraninite, respectively. Similarly to Mo, authigenic U uptake is active at two fronts within the SMTZ, paralleled by increases in dissolved sulfide levels, suggesting coupling between sulfide production and U reduction. Our results imply that both Mo and U could provide viable proxies for mild bottom water deoxygenation in these settings, through the indirect link between seafloor oxygen conditions and the depth of SMTZ. Of these, Mo appears to more robustly capture variations in seafloor oxygen levels due to the significantly higher share of the authigenic pool. However, temporal resolution of these proxies is limited by the vertical offset between seafloor and the zone of authigenic uptake, and the superimposed character of the signal at a given depth due to vertical migrations of the SMTZ. These results have important implications for the use of Mo and U as paleo-redox proxies in other low-salinity coastal settings exposed to eutrophication.Peer reviewe

    Precision mass measurements of radioactive nuclei at JYFLTRAP

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    The Penning trap mass spectrometer JYFLTRAP was used to measure the atomic masses of radioactive nuclei with an uncertainty better than 10 keV. The atomic masses of the neutron-deficient nuclei around the N = Z line were measured to improve the understanding of the rp-process path and the SbSnTe cycle. Furthermore, the masses of the neutron-rich gallium (Z = 31) to palladium (Z = 46) nuclei have been measured. The physics impacts on the nuclear structure and the r-process paths are reviewed. A better understanding of the nuclear deformation is presented by studying the pairing energy around A = 100.Comment: 4 pages and 4 figures, RNB7 conf. pro

    Penning trap at IGISOL

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