Relativistic Precessing Jets and Cosmological Gamma Ray Bursts

We discuss the possibility that gamma-ray bursts may result from cosmological relativistic blob emitting neutron star jets that precess past the line of sight. Beaming reduces the energy requirements, so that the jet emission can last longer than the observed burst duration. One precession mode maintains a short duration time scale, while a second keeps the beam from returning to the line of sight, consistent with the paucity of repeaters. The long life of these objects reduces the number required for production as compared to short lived jets. Blobs can account for the time structure of the bursts. Here we focus largely on kinematic and time scale considerations of beaming, precession, and blobs--issues which are reasonably independent of the acceleration and jet collimation mechanisms. We do suggest that large amplitude electro-magnetic waves could be a source of blob acceleration.Comment: 15 pages, plain TeX, accepted to ApJ

Contract production of turkeys : a study of contractual or vertical integration in turkey production in Missouri that may have implications for other farm commodities

Caption title.Includes bibliographical references

Lysosomal trafficking functions of mucolipin-1 in murine macrophages

BACKGROUND:Mucolipidosis Type IV is currently characterized as a lysosomal storage disorder with defects that include corneal clouding, achlorhydria and psychomotor retardation. MCOLN1, the gene responsible for this disease, encodes the protein mucolipin-1 that belongs to the "Transient Receptor Potential" family of proteins and has been shown to function as a non-selective cation channel whose activity is modulated by pH. Two cell biological defects that have been described in MLIV fibroblasts are a hyperacidification of lysosomes and a delay in the exit of lipids from lysosomes.RESULTS:We show that mucolipin-1 localizes to lysosomal compartments in RAW264.7 mouse macrophages that show subcompartmental accumulations of endocytosed molecules. Using stable RNAi clones, we show that mucolipin-1 is required for the exit of lipids from these compartments, for the transport of endocytosed molecules to terminal lysosomes, and for the transport of the Major Histocompatibility Complex II to the plasma membrane.CONCLUSION:Mucolipin-1 functions in the efficient exit of molecules, destined for various cellular organelles, from lysosomal compartments.This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at [email protected]

Chandra Monitoring of the Candidate Anomalous X-ray Pulsar AX J1845.0-0258

The population of clearly identified anomalous X-ray pulsars has recently grown to seven, however, one candidate anomalous X-ray pulsar (AXP) still eludes re-confirmation. Here, we present a set of seven Chandra ACIS-S observations of the transient pulsar AX J1845.0-0258, obtained during 2003. Our observations reveal a faint X-ray point source within the ASCA error circle of AX J1845.0-0258's discovery, which we designate CXOU J184454.6-025653 and tentatively identify as the quiescent AXP. Its spectrum is well described by an absorbed single-component blackbody (kT~2.0 keV) or power law (Gamma~1.0) that is steady in flux on timescales of at least months, but fainter than AX J1845.0-0258 was during its 1993 period of X-ray enhancement by at least a factor of 13. Compared to the outburst spectrum of AX J1845.0-0258, CXOU J184454.6-025653 is considerably harder: if truly the counterpart, then its spectral behaviour is contrary to that seen in the established transient AXP XTE J1810-197, which softened from kT~0.67 keV to ~0.18 keV in quiescence. This unexpected result prompts us to examine the possibility that we have observed an unrelated source, and we discuss the implications for AXPs, and magnetars in general.Comment: 4 pages, 3 figures. To be published in the proceedings of the conference "Isolated Neutron Stars: from the Interior to the Surface" (April 24-28, 2006, London, UK), eds. D. Page, R. Turolla, & S. Zan

Effect of Instruction on EMG Activity of the Rectus Abdominis during a Crunch on a Swiss Exercise Ball

Purpose: The purpose of this study was to assess the benefit of instruction from a physical therapist in participant performance of an abdominal crunch on a Swiss ball, determined through electromyography (EMG) of the rectus abdominis. Subjects: Our subjects included male (n=15) and female (n=15) college students between the ages of 18-50 years old. Exclusion criteria included a history of low back pain, prior spine surgery, pregnancy, previous formal instruction of crunches on a Swiss ball, and an allergic reaction to rubbing alcohol. Instrumentation: EMG biofeedback was used to test rectus abdominis muscle activity. This activity was transmitted by a Noraxon Telemy08 telemetry unit (Noraxan USA, 13430 North Scottsdale Rd., AZ 85254). Data was collected by the Noraxon Telemy08 receiver. The peak Notus5 system (Peak Performance, Englewood, CO) was used to store and analyze the EMG data. Procedure: Participants performed a manual muscle test of the rectus abdominis muscle and the EMG activity was recorded and used for base line data. The subjects were then asked to perform 10 abdominal crunches on the ball without any instruction. This data was recorded, and then verbal instruction on proper technique of an abdominal crunch on the ball was given. Following instruction, participants had one minute to rest, and then perform an additional 10 crunches using the new correct posture. Data Analysis: For statistical analysis, a repeated-measures t-test was used with an alpha level of .05. Results: There was no significant difference when comparing the mean values of EMG muscle activity of the upper rectus abdominis pre and post instruction and lower rectus abdominis pre and post instruction. (78.05 and 76.14 --70.50 and 69.73 respectively) Conclusions and Clinical Implications: In conclusion our study results did not support a significant difference in rectus abdominis muscle activity after instruction measured through EMG analysis. Injury due to over training, muscle imbalances or muscle strains could be avoided when patients are given instructions and demonstrate proper technique

Histone variant innovation in a rapidly evolving chordate lineage

Contains fulltext : 91896.pdf (publisher's version ) (Open Access

A deep Large Binocular Telescope view of the Canes Venatici I dwarf galaxy

We present the first deep color-magnitude diagram of the Canes Venatici I (CVnI) dwarf galaxy from observations with the wide field Large Binocular Camera on the Large Binocular Telescope. Reaching down to the main-sequence turnoff of the oldest stars, it reveals a dichotomy in the stellar populations of CVnI: it harbors an old (> 10 Gyr), metal-poor ([Fe/H] ~ -2.0) and spatially extended population along with a much younger (~ 1.4-2.0 Gyr), 0.5 dex more metal-rich, and spatially more concentrated population. These young stars are also offset by 64_{-20}^{+40} pc to the East of the galaxy center. The data suggest that this young population, which represent ~ 3-5 % of the stellar mass of the galaxy within its half-light radius, should be identified with the kinematically cold stellar component found by Ibata et al. (2006). CVnI therefore follows the behavior of the other remote MW dwarf spheroidals which all contain intermediate age and/or young populations: a complex star formation history is possible in extremely low-mass galaxies.Comment: 4 pages, 3 figures, accepted for publication in ApJL. Minor changes, conclusions unchange

Switching of magnetic domains reveals evidence for spatially inhomogeneous superconductivity

The interplay of magnetic and charge fluctuations can lead to quantum phases with exceptional electronic properties. A case in point is magnetically-driven superconductivity, where magnetic correlations fundamentally affect the underlying symmetry and generate new physical properties. The superconducting wave-function in most known magnetic superconductors does not break translational symmetry. However, it has been predicted that modulated triplet p-wave superconductivity occurs in singlet d-wave superconductors with spin-density wave (SDW) order. Here we report evidence for the presence of a spatially inhomogeneous p-wave Cooper pair-density wave (PDW) in CeCoIn5. We show that the SDW domains can be switched completely by a tiny change of the magnetic field direction, which is naturally explained by the presence of triplet superconductivity. Further, the Q-phase emerges in a common magneto-superconducting quantum critical point. The Q-phase of CeCoIn5 thus represents an example where spatially modulated superconductivity is associated with SDW order