39 research outputs found
Focused Ion Beam Fabrication
Contains summary of research program and reports on four research projects.Charles Stark Draper Laboratory (Contract DL-H-225270)Hughes Research LaboratoriesInternational Business Machines, Inc. (Contract 456614)Nippon Telegraph and Telephone, Inc.U.S. Navy - Office of Naval Research (Contract N00014-84-K-0073)U.S. Department of Defense (Contract MDA903-85-C-0215)Hitachi Central Research Laborator
CP violation and CKM phases from angular distributions for decays into admixtures of CP eigenstates
We investigate the time-evolutions of angular distributions for decays
into final states that are admixtures of CP-even and CP-odd configurations. A
sizable lifetime difference between the mass eigenstates allows a probe
of CP violation in time-dependent untagged angular distributions. Interference
effects between different final state configurations of , determine the Wolfenstein parameter from
untagged data samples, or -- if one uses as an additional
input -- the notoriously difficult to measure CKM angle . Another
determination of is possible by using isospin symmetry of strong
interactions to relate untagged data samples of
and . We note that the untagged angular
distribution for provides interesting information about
electroweak penguins.Comment: 19 pages, LaTeX, no figure
BCAA catabolism in brown fat controls energy homeostasis through SLC25A44.
Branched-chain amino acid (BCAA; valine, leucine and isoleucine) supplementation is often beneficial to energy expenditure; however, increased circulating levels of BCAA are linked to obesity and diabetes. The mechanisms of this paradox remain unclear. Here we report that, on cold exposure, brown adipose tissue (BAT) actively utilizes BCAA in the mitochondria for thermogenesis and promotes systemic BCAA clearance in mice and humans. In turn, a BAT-specific defect in BCAA catabolism attenuates systemic BCAA clearance, BAT fuel oxidation and thermogenesis, leading to diet-induced obesity and glucose intolerance. Mechanistically, active BCAA catabolism in BAT is mediated by SLC25A44, which transports BCAAs into mitochondria. Our results suggest that BAT serves as a key metabolic filter that controls BCAA clearance via SLC25A44, thereby contributing to the improvement of metabolic health
Destruction of chemical warfare surrogates using a portable atmospheric pressure plasma jet
Today’s reality is connected with mitigation of threats from the new chemical and biological warfare agents. A novel investigation of cold plasmas in contact with liquids presented in this paper demonstrated that the chemically reactive environment produced by atmospheric pressure plasma jet (APPJ) is potentially capable of rapid destruction of chemical warfare agents in a broad spectrum. The decontamination of three different chemical warfare agent surrogates dissolved in liquid is investigated by using an easily transportable APPJ. The jet is powered by a kHz signal source connected to a low-voltage DC source and with He as working gas. The detailed investigation of electrical properties is performed for various plasmas at different distances from the sample. The measurements of plasma properties in situ are supported by the optical spectrometry measurements, whereas the high performance liquid chromatography measurements before and after the treatment of aqueous solutions of Malathion, Fenitrothion and Dimethyl Methylphosphonate. These solutions are used to evaluate destruction and its efficiency for specific neural agent simulants. The particular removal rates are found to be from 56% up to 96% during 10 min treatment. The data obtained provide basis to evaluate APPJ’s efficiency at different operating conditions. The presented results are promising and could be improved with different operating conditions and optimization of the decontamination process
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Semiochemical-based alternatives to synthetic toxicant insecticides for pollen beetle management
There is an urgent need to develop sustainable pest management systems to protect arable crops in order to replace the current over-reliance on synthetic insecticides. Semiochemicals are insect- or plant-derived chemicals that are used by organisms as information signals. Integrated pest management tools are currently in development that utilise semiochemicals to manipulate the behaviour of pest insects and their natural enemies to provide effective control of pests within the crop. These innovative tools usually require fewer inputs and can involve multiple elements therefore reducing the likelihood of resistance developing compared with use of synthetic toxicants. We review here the life cycle of the pollen beetle Brassicogethes aeneus (previously known as Meligethes aeneus) which is a pest insect of oilseed rape (Brassica napus) and describe the current knowledge of any behaviour mediated by semiochemicals in this species. We discuss the behavioural processes where semiochemical-based control approaches may be appropriate and consider how these approaches could be integrated into an integrated pest management strategy for this important arable crop
Observation of Gamma Rays from the Galactic Center with the MAGIC Telescope
Recently, the Galactic Center has been reported to be a source of very high
energy (VHE) gamma-rays by the VERITAS, CANGAROO and HESS experiments. The
energy spectra as measured by these experiments show substantial differences.
In this Letter we present MAGIC observations of the Galactic Center, resulting
in the detection of a differential gamma-ray flux consistent with a steady,
hard-slope power law, described as dN/(dA dt dE) = (2.9+/-0.6)*10^{-12}
(E/TeV)^{-2.2+/-0.2} cm^{-2}s^{-1}TeV^{-1}. The gamma-ray source is centered at
(Ra, Dec)=(17h 45m 20s, -29deg 2'. This result confirms the previous
measurements by the HESS experiment and indicates a steady source of TeV
gamma-rays. We briefly describe the observational technique used, the procedure
implemented for the data analysis, and discuss the results in the perspective
of different models proposed for the acceleration of the VHE gamma-rays.Comment: ApJL submitte
Variable Very High Energy Gamma-ray Emission from the Microquasar LS I +61 303
Microquasars are binary star systems with relativistic radio-emitting jets.
They are potential sources of cosmic rays and laboratories for elucidating the
physics of relativistic jets. Here we report the detection of variable
gamma-ray emission above 100 gigaelectron volts from the microquasar LS I +61
303. Six orbital cycles were recorded. Several detections occur at a similar
orbital phase, suggesting the emission is periodic. The strongest gamma-ray
emission is not observed when the two stars are closest to one another,
implying a strong orbital modulation of the emission or the absorption
processes.Comment: 11 pages with 4 figure
Variable Very High Energy Gamma-ray Emission from the Microquasar LS I +61 303
Microquasars are binary star systems with relativistic radio-emitting jets.
They are potential sources of cosmic rays and laboratories for elucidating the
physics of relativistic jets. Here we report the detection of variable
gamma-ray emission above 100 gigaelectron volts from the microquasar LS I +61
303. Six orbital cycles were recorded. Several detections occur at a similar
orbital phase, suggesting the emission is periodic. The strongest gamma-ray
emission is not observed when the two stars are closest to one another,
implying a strong orbital modulation of the emission or the absorption
processes.Comment: 11 pages with 4 figure
Observation of VHE Gamma Radiation from HESS J1834-087/W41 with the MAGIC Telescope
Recently, the HESS array has reported the detection of gamma-ray emission
above a few hundred GeV from eight new sources located close to the Galactic
Plane. The source HESS J1834-087 is spatially coincident with SNR G23.3-0.3
(W41). Here we present MAGIC observations of this source, resulting in the
detection of a differential gamma-ray flux consistent with a power law,
described as dN/(dA dt dE) = (3.7 +/- 0.6)*10^(-12) (E/TeV)^(-2.5 +/- 0.2) \
cm^(-2)s^(-1)TeV^(-1). We confirm the extended character of this flux. We
briefly discuss the observational technique used, the procedure implemented for
the data analysis, and put this detection in the perspective of the molecular
environment found in the region of W41. We present 13CO and 12CO emission maps
showing the existence of a massive molecular cloud in spatial superposition
with the MAGIC detection.Comment: Accepted by ApJ Letter