3,534 research outputs found
Neutralino annihilation into a photon and a Z boson
No full textA full one-loop calculation of neutralino S-wave annihilation into the Z gamma final state is performed in the minimal supersymmetric extension of the standard model. This process, like the similar one with two photons in the final state, may be of importance for the indirect detection of supersymmetric dark matter through the very narrow gamma ray line that would result from neutralino annihilations in the galactic halo. We give the complete analytical formulas for this loop-induced process and treat the case of a pure Higgsino as a first application of our expressions. Predictions for the gamma line flux are given for the halo model which is of the form suggested by Kravtsov et al. and for the profile proposed by Navarro, Frenk and White, For heavy neutralinos, the lines from 2 gamma and Z gamma would have indistiguishable energy in a realistic detector, making the fluxes add and facilitating discovery. For lighter neutralinos, the positions and relative strengths of the two lines would give valuable information on the nature of the supersymmetric dark matter particles
Full one-loop calculation of neutralino annihilation into two photons
No full textFor the first time, a full one-loop calculation of the process chi chi --> 2 gamma is performed, where chi is the lightest neutralino in the minimal supersymmetric extension of the Standard Model. This process is of interest for dark matter detection, since it would give a sharp gamma ray line with E-gamma = m(chi). We improve upon and correct published formulas, and give cross sections for supersymmetric models with chi masses between 30 GeV and several TeV. We find a new contribution, previously neglected, which enhances the 2 gamma rate for TeV higgsinos by up to an order of magnitude. As a byproduct, we obtain a new expression for the related process chi chi --> 2 gluons, which on the other hand can be smaller than previously calculated
[Portrait of young African American woman]
No full textPortrait of a woman.Recto: [imprinted] Bergstrom Waco, Tex.; Verso: [imprinted] J. L. Bergstrom Portraits; 503 1/2 Austin Street, Waco, Texas; Duplicates can be had at any time
Some results on the Bergstrom and Minkowski inequalities
No full textAbstractWe offer a generalization of the Bergstrom inequalities for positive definite matrices expressed in terms of Schur complements. Then we use the Bergstrom inequalities for certain M-matrices to obtain the Minkowski inequality. We show that our results are not comparable with known results of K. Fan and J. Miao
Presentation of television to the Gonzales Warm Springs Foundation for Crippled Children
No full textImage shows 6-year-old Charlotte Stanley of Lake Jackson, Texas in her wheelchair with L-R: Mr. Taylor, the administrator; Mrs. W.L. Glenewinkel of Kingsbury; Mrs. E.V. Conley of Lockhart; Mrs. O.T. Bergstrom of Round Rock (second from right); and Mrs. Ruth King of San Marcos.A 21-inch television set was presented by the Home Demonstration Clubs of District 10 in a ceremony at the Hospital on Thursday, September 8th, 1955
Spectral gamma-ray signatures of cosmological dark matter annihilations
No full textWe propose a new signature for weakly interacting massive particle (WIMP) dark matter, a spectral feature in the diffuse extragalactic gamma-ray radiation. This feature, a sudden drop of the gamma-ray intensity at an energy corresponding to the WIMP mass, comes from the asymmetric distortion of the line due to WIMP annihilation into two gamma rays caused by the cosmological redshift. Unlike other proposed searches for a line signal, this method is not very sensitive to the exact dark matter density distribution in halos and subhalos
Mitochondrial bioenergetics and fibre type assessments in microbiopsy vs Bergstrom percutaneous sampling of human skeletal muscle
No full textMicrobiopsies of human skeletal muscle are increasingly adopted by physiologists for a variety of experimental assays given the reduced invasiveness of this procedure compared to the classic Bergstrom percutaneous biopsy technique. However, a recent report demonstrated lower mitochondrial respiration in saponin-permeabilized muscle fibre bundles (PmFB) prepared from microbiopsies vs Bergstrom biopsies. We hypothesized that ADP-induced contraction (rigor) of smaller length microbiopsy PmFB causes a greater reduction in maximal respiration vs Bergstrom, such that respiration could be increased by a myosin II ATPase-inhibitor (Blebbistatin; BLEB). 11 males and females each received a 2 mm diameter percutaneous microbiopsy and a 5 mm diameter Bergstrom percutaneous biopsy in opposite legs. Glutamate/malate (5 mM/0.5 mM) - supported respiration in microbiopsy PmFB was lower than Bergstrom at submaximal concentrations of ADP. 5 μM BLEB reduced this impairment such that there were no differences relative to Bergstrom +/- BLEB. Surprisingly, pyruvate (5 mM)-supported respiration was not different between either biopsy technique +/- BLEB, whereas BLEB increased succinate-supported respiration in Bergstrom only. H2O2 emission was lower in microbiopsy PmFB compared to Bergstrom PmFB in the presence of BLEB. Microbiopsies contained fewer type I fibres (37% vs 47%) and more type IIX fibres (20% vs 8%) compared to Bergstrom possibly due to sampling site depth and/or longitudinal location. These findings suggest that smaller diameter percutaneous biopsies yield lower glutamate-supported mitochondrial respiratory kinetics which is increased by preventing ADP-induced rigor with myosin inhibition. Microbiopsies of human skeletal muscle can be utilized for assessing mitochondrial respiratory kinetics in PmFB when assay conditions are supplemented with BLEB, but fibre type differences with this method should be considered
Recommended from our members
The Regional Economic Impact of New Airport Construction: The Case of Austin-Bergstrom International Airport
Get PDFIn the late 1980, it became apparent that Austin’s Robert Mueller Municipal Airport would not be equal to the demands generated by the growth of the city surrounding it. Consequently, in September 1993, Austin voters approved 585 million Austin-Bergstrom International Airport (ABIA), the largest construction project in the city’s history, opened for the cargo operations in 1997 and began passenger operations in 1999. ABIA provides a strong example of the immediate economic benefits and pressing policy issues that accompany large infrastructure projects, such as the building of a new airport.IC2 Institut
“The fate of the Data Retention Directive: about mass surveillance and fundamental rights in the EU legal order”
No full textThe chapter explores the fate of the Data Retention Directive, the Digital Rights Ireland case and its implications for mass surveillance and data protection. After the Introduction, setting the issue within the context of Snowden’s revelations, the chapter presents the Data Retention Directive and the domestic resistance it has met; it then moves to highlight the judgment, its reasoning and motivations. The chapter discusses the judgment’s implications both in the perspective of national data retention legislation and in the European perspective: by outlawing generalized mass surveillance the Digital Rights Ireland judgment sets benchmarks having consequences also for other European instruments, from the PNR to the Safe Harbour Scheme (recently invalidated by the Schrems judgment), indicating that the judgment is therefore displaying some extraterritorial consequences. The chapter concludes reflecting on the judgment in the perspective of Kadi, reading it as the Court of Justice’s contribution on European counter-terrorism policies and ‘state of exception’
- …
