4,489 research outputs found
On the Direct Detection of Dark Matter Annihilation
We investigate the direct detection phenomenology of a class of dark matter
(DM) models in which DM does not directly interact with nuclei, {but rather}
the products of its annihilation do. When these annihilation products are very
light compared to the DM mass, the scattering in direct detection experiments
is controlled by relativistic kinematics. This results in a distinctive recoil
spectrum, a non-standard and or even absent annual modulation, and the ability
to probe DM masses as low as a 10 MeV. We use current LUX data to show
that experimental sensitivity to thermal relic annihilation cross sections has
already been reached in a class of models. Moreover, the compatibility of dark
matter direct detection experiments can be compared directly in
space without making assumptions about DM astrophysics, mass, or scattering
form factors. Lastly, when DM has direct couplings to nuclei, the limit from
annihilation to relativistic particles in the Sun can be stronger than that of
conventional non-relativistic direct detection by more than three orders of
magnitude for masses in a 2-7 GeV window.Comment: 4 pages, 3 figures, PRL versio
Halo Independent Direct Detection of Momentum-Dependent Dark Matter
We show that the momentum dependence of dark matter interactions with nuclei
can be probed in direct detection experiments without knowledge of the dark
matter velocity distribution. This is one of the few properties of DM
microphysics that can be determined with direct detection alone, given a signal
of dark matter in multiple direct detection experiments with different targets.
Long-range interactions arising from the exchange of a light mediator are one
example of momentum-dependent DM. For data produced from the exchange of a
massless mediator we find for example that the mediator mass can be constrained
to be MeV for DM in the 20-1000 GeV range in a halo-independent
manner.Comment: 15 pages, 4 figures; updated to match published versio
Energy efficient engine. Low pressure turbine test hardware detailed design report
The low pressure turbine for the energy efficient engine is a five-stage configuration with moderate aerodynamic loading incorporating advanced features of decambered airfoils and extended blade overlaps at platforms and shrouds. Mechanical integrity of 18,000 hours on flowpath components and 36,000 hours on all other components is achieved along with no aeromechanical instabilities within the steady-state operating range. Selection of a large number (156) of stage 4 blades, together with an increased stage 4 vane-to-blade gap, assists in achieving FAR 36 acoustic goals. Active clearance control (ACC) of gaps at blade tips and interstage seals is achieved by fan air cooling judiciously applied at responsive locations on the casing. This ACC system is a major improvement in preventing deterioration of the 0.0381 cm (0.015 in.) clearances required to meet the integrated-core/low-spool turbine efficiency goal of 91.1% and the light propulsion system efficiency goal of 91.7%
The Control and Treatment of East African Relapsing Fever, With Special Reference to Aureomycin and Terramycin
Abstract Not Provided
UA3/1/2 Henry Cherry - Earl Sullenger Correspondence
Letter from T. Earl Sullenger WKU alum requesting a recommendation from Henry Cherry in order to obtain a commission in the U.S. Navy. Text:
Allison DII St. Elizabeth\u27s Hospital Washington, D.C.
Pres. H.H. Cherry Bowling Green, Ky.
My dear Friend:
Please pardon me for asking for another favor, but I am making application for a Commission in the U.S. Navy. I know that a letter from you will be a great assistance to me.
Hoping to receive the letter at once and thanking you in advance, I am
Your W.K.S.N. friend T. Earl Sullenger
Cherry\u27s reply recounts the establishment of the Student Army Training Corps and the results of the recent influenza epidemic in Bowling Green
Gonadal hormones, but not sex, affect the acquisition and maintenance of a Go/No-Go odor discrimination task in mice
In mice, olfaction is crucial for identifying social odors (pheromones) that signal the presence of suitable mates. We used a custom-built olfactometer and a thirst-motivated olfactory discrimination Go/No-Go (GNG) task to ask whether discrimination of volatile odors is sexually dimorphic and modulated in mice by adult sex hormones. Males and females gonadectomized prior to training failed to learn even the initial phase of the task, which involved nose poking at a port in one location obtaining water at an adjacent port. Gonadally intact males and females readily learned to seek water when male urine (S+) was present but not when female urine (S−) was present; they also learned the task when non-social odorants (amyl acetate, S+; peppermint, S−) were used. When mice were gonadectomized after training the ability of both sexes to discriminate urinary as well as non-social odors was reduced; however, after receiving testosterone propionate (castrated males) or estradiol benzoate (ovariectomized females), task performance was restored to pre-gonadectomy levels. There were no overall sex differences in performance across gonadal conditions in tests with either set of odors; however, ovariectomized females performed more poorly than castrated males in tests with non-social odors. Our results show that circulating sex hormones enable mice of both sexes to learn a GNG task and that gonadectomy reduces, while hormone replacement restores, their ability to discriminate between odors irrespective of the saliency of the odors used. Thus, gonadal hormones were essential for both learning and maintenance of task performance across sex and odor type.We thank David Giese for help in programming the apparatus used in GNG testing and Alberto Cruz-Martin for comments on an early version of the manuscript. This work was supported by NIDCD grant DC008962 to JAC. (DC008962 - NIDCD grant)Accepted manuscrip
Corporate Acquisition Criteria: New Evidence
P.R. Chandy is an Assistant Professor of Finance at North Texas State University. Richard T. Cherry is Professor of Finance, College of Business, Lamar University
An evaluation of the presence of pathogens on broilers raised on poultry litter treatment-treated litter
Two trials were conducted to evaluate the presence of salmonella, campylobacter, and generic Escherichia coli on broilers raised on Poultry Litter Treatment (PLT®)-enhanced litter in comparison with those raised on untreated litter. Two Company A farms included three houses on each farm as the treated group and three houses per farm as controls. Two complete growouts were evaluated on each farm. The Company B study included 10 farms with two paired houses per farm, one house as the treated group and one house as the control. One growout was evaluated per farm. The pathogen sampling consisted of litter sampling and whole bird rinses on the farm and in the processing plant. Litter pH, ammonia concentration, total litter bacteria, temperatures, and humidity were also recorded. The study with Company A resulted in lower mean levels of pH, ammonia concentration, total litter bacteria, litter E. coli, and bird rinse counts for salmonella and E. coli in houses treated with PLT®. The results for Company B closely resembled those for Company A, but also included campylobacter data, which showed no difference between treated and control groups. The data indicate that PLT® may be a beneficial component for on-farm pathogen reduction
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