Abstract We describe a new concept for a radiation detector based on extruded scintillator technology and commercially available solid-state photo-detectors. The detector is simple in construction, ...robust, very efficient, cost-effective and easily scalable in size from tens of cm 2 to tens of m 2 . We describe two possible applications: flagging radioactive food contamination and detection of illicit radioactive materials, such as those potentially used in a dirty bomb.
CONTEXT Evaluation of trends in organ dysfunction in critically ill patients
may help predict outcome. OBJECTIVE To determine the usefulness of repeated measurement the Sequential Organ
Failure ...Assessment (SOFA) score for prediction of mortality in intensive care
unit (ICU) patients. DESIGN Prospective, observational cohort study conducted from April 1 to July
31, 1999. SETTING A 31-bed medicosurgical ICU at a university hospital in Belgium. PATIENTS Three hundred fifty-two consecutive patients (mean age, 59 years) admitted
to the ICU for more than 24 hours for whom the SOFA score was calculated on
admission and every 48 hours until discharge. MAIN OUTCOME MEASURES Initial SOFA score (0-24), Δ-SOFA scores (differences between
subsequent scores), and the highest and mean SOFA scores obtained during the
ICU stay and their correlations with mortality. RESULTS The initial, highest, and mean SOFA scores correlated well with mortality.
Initial and highest scores of more than 11 or mean scores of more than 5 corresponded
to mortality of more than 80%. The predictive value of the mean score was
independent of the length of ICU stay. In univariate analysis, mean and highest
SOFA scores had the strongest correlation with mortality, followed by Δ-SOFA
and initial SOFA scores. The area under the receiver operating characteristic
curve was largest for highest scores (0.90; SE, 0.02; P<.001 vs initial score). When analyzing trends in the SOFA score
during the first 96 hours, regardless of the initial score, the mortality
rate was at least 50% when the score increased, 27% to 35% when it remained
unchanged, and less than 27% when it decreased. Differences in mortality were
better predicted in the first 48 hours than in the subsequent 48 hours. There
was no significant difference in the length of stay among these groups. Except
for initial scores of more than 11 (mortality rate >90%), a decreasing score
during the first 48 hours was associated with a mortality rate of less than
6%, while an unchanged or increasing score was associated with a mortality
rate of 37% when the initial score was 2 to 7 and 60% when the initial score
was 8 to 11. CONCLUSIONS Sequential assessment of organ dysfunction during the first few days
of ICU admission is a good indicator of prognosis. Both the mean and highest
SOFA scores are particularly useful predictors of outcome. Independent of
the initial score, an increase in SOFA score during the first 48 hours in
the ICU predicts a mortality rate of at least 50%.
The goal of nuSTORM is to provide well-defined neutrino beams for precise measurements of neutrino cross-sections and oscillations. The nuSTORM decay ring is a compact racetrack storage ring with a ...circumference of ∼480 m that incorporates large aperture (60 cm diameter) magnets. There are many challenges in the design. In order to incorporate the Orbit Combination section (OCS), used for injecting the pion beam into the ring, a dispersion suppressor is needed adjacent to the OCS . Concurrently, in order to maximize the number of useful muon decays, strong bending dipoles are needed in the arcs to minimize the arc length. These dipoles create strong chromatic effects, which need to be corrected by nonlinear sextupole elements in the ring. In this paper, a FODO racetrack ring design and its optimization using sextupolar fields via both a Genetic Algorithm (GA) and a Simulated Annealing (SA) algorithm will be discussed.
Abstract
A Cosmic Muon Veto (CMV) detector using extruded scintillators is being designed around the mini-Iron Calorimeter detector at the transit campus of the India-based Neutrino Observatory, ...Madurai for measuring its efficiency at shallow depth underground experiments. The scintillation signal is transmitted through a Wavelength Shifting (WLS) fibre and readout by Hamamatsu Silicon-Photomultipliers (SiPMs). A Light Emitting Diode (LED) system is included on the front-end readout for in-situ calibration of the gain of each SiPM. A characterization system was developed for the measurement of gain and choice of the overvoltage (
V
ov
) of SiPMs using the LED as well as a cosmic muon telescope. The
V
ov
is obtained by studying the noise rate, the gain of the SiPM, and the muon detection efficiency. In case of any malfunction of the LED system during the operation, the SiPM can also be calibrated with the noise data as well as using radioactive sources. This paper describes the basic characteristics of the SiPM and the comparison of the calibration results using all three methods, as well as the
V
ov
of the SiPMs and muon selection criteria for the veto detector.
Muon radiography is a technique based on the measurement of absorption profiles of muons as they pass through matter. This measurement allows to obtain an image of the inner structure of large volume ...objects and is suitable to be applied in several fields, such as volcanology, archaeology and civil engeneering. One of the main applications concerns the study of volcanic structures; indeed it is possible to use this technique to measure the mass distribution inside the edifice of a volcano providing useful information to better understand the possible eruption mechanisms. The MURAVES (MUon RAdiography of VESuvius) project aims to the study of the summital cone of Mt. Vesuvius near Naples in Italy, one of the most dangerous active volcanoes in the world. The MURAVES apparatus is a modular, robust muon hodoscope system with a low power consumption, optimized to be used in inhospitable environments like the surroundings of volcanoes. The complete detection system is an array of identical tracking modules, each with an area of 1 m2, based on the use of plasic scintillators. The technologies, the status and the data analysis strategy of the experiment will be presented in this paper.
Muon Radiography or muography is based on the measurement of the absorption or scattering of cosmic muons, as they pass through the interior of large scale bodies, In particular, absorption muography ...has been applied to investigate the presence of hidden cavities inside the pyramids or underground, as well as the interior of volcanoes’ edifices. The MURAVES project has the challenging aim of investigating the density distribution inside the summit of Mt. Vesuvius. The information, together with that coming from gravimetric measurements, is useful as input to models, to predict how an eruption may develop. The MURAVES apparatus is a robust and low power consumption muon telescope consisting of an array of three identical and independent muon trackers, which provide in a modular way a total sensitive area of three square meters. Each tracker consists of four doublets of planes of plastic scintillator bars with orthogonal orientation, optically coupled to Silicon photomultipliers for the readout of the signal. The muon telescope has been installed on the slope of the volcano and has collected a first set of data, which are being analyzed.
Ionization cooling is the preferred method for producing bright muon beams. This cooling technique requires the operation of normal conducting, radio-frequency (rf) accelerating cavities within the ...multi-tesla fields of dc solenoid magnets. Under these conditions, cavities exhibit increased susceptibility to rf breakdown, which can damage cooling channel components and imposes limits on channel length and transmission efficiency. We report, for the first time, stable high-vacuum, normal-conducting cavity operation at gradients of50MV/min an external magnetic field of three tesla, through the use of beryllium cavity elements. This eliminates a significant technical risk that has previously been inherent in ionization cooling channel designs.
Three-Dimensional Structure of a Purple Lipoxygenase Skrzypczak-Jankun, Ewa; Bross, Rebecca A; Carroll, Richard T ...
Journal of the American Chemical Society,
11/2001, Letnik:
123, Številka:
44
Journal Article
Recenzirano
Polyunsaturated fatty acid metabolism is governed primarily by two enzymes, prostaglandin H synthase and lipoxygenase. The crystal structure of the metastable product-oxidized purple form of soybean ...lipoxygenase-3 was determined at 2.0 Å resolution. The data reveal that the chromophore corresponds to an iron-peroxide complex, a potential intermediate in the catalyzed reaction. A significant alteration of the iron site accompanies the formation of the complex. The structure, the first for a fatty acid-lipoxygenase complex, also reveals an unexpected mode of binding, and identifies amino acid residues that may play significant roles in catalysis, regio- and stereoselectivity.
Abstract
The United States has a rich history in high energy particle
accelerators and colliders — both lepton and hadron machines,
which have enabled several major discoveries in elementary particle
...physics. To ensure continued progress in the field, U.S. leadership
as a key partner in building next generation collider facilities
abroad is essential; also critically important is to prepare to host
an energy frontier collider in the U.S. once the construction of
the LBNF/DUNE project is completed. In this paper, we briefly
discuss the ongoing and potential U.S. engagement in proposed
collider projects abroad and present a number of future collider
options we have studied for hosting an energy frontier collider in
the U.S. We also call for initiating an integrated national R&D
program in the U.S. now, focused on future colliders.
Based on theoretical perspectives from the work/family literature, this study tested a model for examining expatriate families' adjustment while on global assignments as an antecedent to expatriates' ...adjustment to working in a host country. Data were collected from 110 families that had been relocated for global assignments. Longitudinal data, assessing family characteristics before the assignment and cross-cultural adjustment approximately 6 months into the assignment, were coded. This study found that family characteristics (family support, family communication, family adaptability) were related to expatriates' adjustment to working in the host country. As hypothesized, the families' cross-cultural adjustment mediated the effect of family characteristics on expatriates' host-country work adjustment.
PDF
