1,039 research outputs found

    Intersecting non-SUSY pp-brane with chargeless 0-brane as black pp-brane

    Get PDF
    Unlike BPS pp-brane, non-supersymmetric (non-susy) pp-brane could be either charged or chargeless. As envisaged in [hep-th/0503007], we construct an intersecting non-susy pp-brane with chargeless non-susy qq-brane by taking T-dualities along the delocalized directions of the non-susy qq-brane solution delocalized in (p−q)(p-q) transverse directions (where p≄qp\geq q). In general these solutions are characterized by four independent parameters. We show that when q=0q=0 the intersecting charged as well as chargeless non-susy pp-brane with chargeless 0-brane can be mapped by a coordinate transformation to black pp-brane when two of the four parameters characterizing the solution take some special values. For definiteness we restrict our discussion to space-time dimensions d=10d=10. We observe that parameters characterizing the black brane and the related dynamics are in general in a different branch of the parameter space from those describing the brane-antibrane annihilation process. We demonstrate this in the two examples, namely, the non-susy D0-brane and the intersecting non-susy D4 and D0-branes, where the solutions with the explicit microscopic descriptions are known.Comment: 25 page

    Probing the Turbulence Dissipation Range and Magnetic Field Strengths in Molecular Clouds

    Full text link
    We study the turbulent velocity dispersion spectra of the coexistent HCN and HCO+ molecular species as a function of length scale in the M17 star-forming molecular cloud. We show that the observed downward shift of the ion's spectrum relative to that of the neutral is readily explained by the existence of an ambipolar diffusion range within which ion and neutral turbulent energies dissipate differently. We use these observations to evaluate this decoupling scale and show how to estimate the strength of the plane-of-the-sky component of the embedded magnetic field in a completely novel way.Comment: 15 pages, 3 figures, accepted for publication in The Astrophysical Journa

    Comparison of 3-, 5-, and 6-Phase Machines for Automotive Charging Applications

    Get PDF
    In this paper, the performance of a 5-phase claw-pole machine/converter system is compared with those of 3-phase and 6-phase systems of the same volume. It is shown that the acoustic output of the 5-phase machine compares favorably with that of the 6-phase machine and is much lower than that of the 3-phase machine over a majority of the operating range. In addition, the output current produced by the 5-phase machine Is, in general, 6-8% higher than those of the 3-phase and 6-phase machines. These results suggest that for maximizing power density while minimizing cost and acoustic noise, 5-phase machines provide a competitive alternative to 6-phase machines of identical volume

    Local Magnetic Field Role in Star Formation

    Get PDF
    We highlight distinct and systematic observational features of magnetic field morphologies in polarized submm dust continuum. We illustrate this with specific examples and show statistical trends from a sample of 50 star-forming regions.Comment: 4 pages, 3 figures; to appear in the EAS Proceedings of the 6th Zermatt ISM Symposium "Conditions and Impact of Star Formation from Lab to Space", September 201

    The alignment of molecular cloud magnetic fields with the spiral arms in M33

    Full text link
    The formation of molecular clouds, which serve as stellar nurseries in galaxies, is poorly understood. A class of cloud formation models suggests that a large-scale galactic magnetic field is irrelevant at the scale of individual clouds, because the turbulence and rotation of a cloud may randomize the orientation of its magnetic field. Alternatively, galactic fields could be strong enough to impose their direction upon individual clouds, thereby regulating cloud accumulation and fragmentation, and affecting the rate and efficiency of star formation. Our location in the disk of the Galaxy makes an assessment of the situation difficult. Here we report observations of the magnetic field orientation of six giant molecular cloud complexes in the nearby, almost face-on, galaxy M33. The fields are aligned with the spiral arms, suggesting that the large-scale field in M33 anchors the clouds.Comment: to appear in Natur

    Quantum Theory Approach for Neutron Single and Double-Slit Diffraction

    Full text link
    We provide a quantum approach description of neutron single and double-slit diffraction, with specific attention to the cold neutron diffraction (λ≈20\lambda \approx 20\AA) carried out by Zeilinger et al. in 1988. We find the theoretical results are good agreement with experimental data.Comment: 10 page

    Two band gap field-dependent thermal conductivity of MgB2MgB_2

    Full text link
    The thermal conductivity Îș(H,T)\kappa (H,T) of the new superconductor MgB2MgB_2 was studied as a function of the temperature and a magnetic field. No anomaly in the thermal conductivity Îș(H,T)\kappa (H,T) is observed around the superconducting transition in absence or presence of magnetic fields up to 14 Tesla; upon that field the superconductivity of MgB2MgB_2 persisted. The thermal conductivity in zero-field shows a TT-linear increase up to 50K. The thermal conductivity is found to increase with increasing field at high fields. We interpret the findings as if there are two subsystems of quasiparticles with different field-dependent characters in a two (LL and SS)-band superconductor reacting differently with the vortex structure. The unusual enhancement of Îș(H,T)\kappa (H ,T) at low temperature but higher than a (Hc2S≃3TH_{c2S}\simeq 3T) critical field is interpreted as a result of the overlap of the low energy states outside the vortex cores in the SS-band.Comment: 6 pages,3 figure

    Ca2+ Cycling in Heart Cells from Ground Squirrels: Adaptive Strategies for Intracellular Ca2+ Homeostasis

    Get PDF
    Heart tissues from hibernating mammals, such as ground squirrels, are able to endure hypothermia, hypoxia and other extreme insulting factors that are fatal for human and nonhibernating mammals. This study was designed to understand adaptive mechanisms involved in intracellular Ca2+ homeostasis in cardiomyocytes from the mammalian hibernator, ground squirrel, compared to rat. Electrophysiological and confocal imaging experiments showed that the voltage-dependence of L-type Ca2+ current (ICa) was shifted to higher potentials in ventricular myocytes from ground squirrels vs. rats. The elevated threshold of ICa did not compromise the Ca2+-induced Ca2+ release, because a higher depolarization rate and a longer duration of action potential compensated the voltage shift of ICa. Both the caffeine-sensitive and caffeine-resistant components of cytosolic Ca2+ removal were more rapid in ground squirrels. Ca2+ sparks in ground squirrels exhibited larger amplitude/size and much lower frequency than in rats. Due to the high ICa threshold, low SR Ca2+ leak and rapid cytosolic Ca2+ clearance, heart cells from ground squirrels exhibited better capability in maintaining intracellular Ca2+ homeostasis than those from rats and other nonhibernating mammals. These findings not only reveal adaptive mechanisms of hibernation, but also provide novel strategies against Ca2+ overload-related heart diseases
    • 

    corecore