1,583 research outputs found
Guided atom laser : a new tool for guided atom optics
We present a guided atom laser. A Bose-Einstein condensate (BEC) is created
in a crossed hybrid magnetic and an elongated optical trap, which acts as a
matterwave guide. Atoms are extracted from the BEC by radio frequency (rf)
outcoupling and then guided in the horizontal optical matterwave guide. This
method allows to control the acceleration of the beam and to achieve large de
Broglie wavelength. We also measure the longitudinal energy of the guided atom
laser using atom optical elements based on a blue light barrier
Tunnel current in self-assembled monolayers of 3-mercaptopropyltrimethoxysilane
The current density-voltage (J-V) characteristics of self assembled
monolayers of 3-mercaptopropyltrimethoxysilane (MPTMS) chemisorbed on the
native oxide surface of p+-doped Si demonstrate the excellent tunnel dielectric
behavior of organic monolayers down to 3 carbon atoms. The J-V characteristics
of MPTMS SAMs on Si are found to be asymmetric, and the direction of
rectification has been found to depend upon the applied voltage range. At
voltages < 2.45V, the reverse bias current was found to be higher than forward
bias current; while at higher voltages this trend was reversed. This result is
in agreement with Simmons theory. The tunnel barrier heights for this short
chain (2.56 and 2.14 eV respectively at Au and Si interfaces) are in good
agreement with the ones for longer chains (>10 carbon atoms) if the chain is
chemisorbed at the electrodes. These results extend all previous experiments on
such molecular tunnel dielectrics down to 3 carbon atoms. This suggests that
these molecular monolayers, having good tunnel behavior (up to 2.5 eV) over a
large bias range, can be used as gate dielectric well below the limits of
Si-based dielectrics.Comment: Small, in pres
Sample Police Officers Duty Manual
A police organization is that part of the government responsibile for enforcing laws and ordinances adopted by elected representatives of the people. The letter of the law determines what a police officer m ust do to discharge the obligation im posed by his oath, but it does not encom pass all of the circum stances which arise in the practical application of these written principles. Understanding of human behavior and application of comm on sense are fundamental to the successful attainment of police obj ectives. These alone, however, are not sufficient to insure the proper handling of every incident. There must be standards of quality and rules for procedure and conduct to serve as guides. These standards, rules and regulations are set forth in this Manual. This Manual prescribes the manner in which m embers of the Police Department will conduct them selves in discharging their sworn obligations. Violations of provisions of this Manual will constitute grounds for disciplinary action
Effect of ready-to-use-therapeutic food supplementation on the nutritional status, mortality and morbidity of children 6 to 60 months in Niger, a cluster randomized trial
Presented at the conference of the American Society of Tropical Medicine and Hygiene 200
Large Logarithms in the Beam Normal Spin Asymmetry of Elastic Electron--Proton Scattering
We study a parity-conserving single-spin beam asymmetry of elastic
electron-proton scattering induced by an absorptive part of the two-photon
exchange amplitude. It is demonstrated that excitation of inelastic hadronic
intermediate states by the consecutive exchange of two photons leads to
logarithmic and double-logarithmic enhancement due to contributions of hard
collinear quasi-real photons. The asymmetry at small electron scattering angles
is expressed in terms of the total photoproduction cross section on the proton,
and is predicted to reach the magnitude of 20-30 parts per million. At these
conditions and fixed 4-momentum transfers, the asymmetry is rising
logarithmically with increasing electron beam energy, following the high-energy
diffractive behavior of total photoproduction cross section on the proton.Comment: 10 pages, 6 figures; typos fixed, a reference adde
Genetic heterogeneity of hepatitis E virus in Darfur, Sudan, and neighboring Chad.
The within-outbreak diversity of hepatitis E virus (HEV) was studied during the outbreak of hepatitis E that occurred in Sudan in 2004. Specimens were collected from internally displaced persons living in a Sudanese refugee camp and two camps implanted in Chad. A comparison of the sequences in the ORF2 region of 23 Sudanese isolates and five HEV samples from the two Chadian camps displayed a high similarity (>99.7%) to strains belonging to Genotype 1. But four isolates collected in one of the Chadian camps were close to Genotype 2. Circulation of divergent strains argues for possible multiple sources of infection
Mechanisms for Lasing with Cold Atoms as the Gain Medium
We realize a laser with a cloud of cold rubidium atoms as gain medium, placed
in a low-finesse cavity. Three different regimes of laser emission are observed
corresponding respectively to Mollow, Raman and Four Wave Mixing mechanisms. We
measure an output power of up to 300 W and present the main properties of
these different lasers in each regime
Effectiveness of ready-to-use therapeutic food compared to a corn/soy-blend-based pre-mix for the treatment of childhood moderate acute malnutrition in Niger.
Standard nutritional treatment of moderate acute malnutrition (MAM) relies on fortified blended flours though their importance to treat this condition is a matter of discussion. With the newly introduced World Health Organization growth standards, more children at an early stage of malnutrition will be treated following the dietary protocols as for severe acute malnutrition, including ready-to-use therapeutic food (RUTF). We compared the effectiveness of RUTF and a corn/soy-blend (CSB)-based pre-mix for the treatment of MAM in the supplementary feeding programmes (SFPs) supported by Médecins Sans Frontières, located in the Zinder region (south of Niger). Children measuring 65 to <110 cm, newly admitted with MAM [weight-for-height (WHM%) between 70% and <80% of the NCHS median] were randomly allocated to receive either RUTF (Plumpy'Nut®, 1000 kcal day(-1)) or a CSB pre-mix (1231 kcal day(-1)). Other interventions were similar in both groups (e.g. weekly family ration and ration at discharge). Children were followed weekly up to recovery (WHM% ≥ 85% for 2 consecutive weeks). In total, 215 children were recruited in the RUTF group and 236 children in the CSB pre-mix group with an overall recovery rate of 79.1 and 64.4%, respectively (p < 0.001). There was no evidence for a difference between death, defaulter and non-responder rates. More transfers to the inpatient Therapeutic Feeding Centre (I-TFC) were observed in the CSB pre-mix group (19.1%) compared to the RUTF group (9.3%) (p = 0.003). The average weight gain up to discharge was 1.08 g kg(-1) day(-1) higher in the RUTF group [95% confidence interval: 0.46-1.70] and the length of stay was 2 weeks shorter in the RUTF group (p < 0.001). For the treatment of childhood MAM in Niger, RUTF resulted in a higher weight gain, a higher recovery rate, a shorter length of stay and a lower transfer rate to the I-TFC compared to a CSB pre-mix. This might have important implications on the efficacy and the quality of SFPs
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