1,962 research outputs found
Use of thermodynamic properties of metal-gas systems as low-pressure standards
Modified version of Sievert's apparatus accurately calibrates low pressure measuring instruments. Metal-gas system is composed of hydrogen in two-phase equilibrium with erbium to obtain reproducible hydrogen pressures
A study of metal oxygen and metal nitrogen systems for use as reduced pressure standards
Metal-oxygen and metal-nitrogen systems for use as reduced pressure standards using Sieverts apparatu
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Implementation and impact of pediatric antimicrobial stewardship programs: a systematic scoping review.
Background: Antibiotics are the most common medicines prescribed to children in hospitals and the community, with a high proportion of potentially inappropriate use. Antibiotic misuse increases the risk of toxicity, raises healthcare costs, and selection of resistance. The primary aim of this systematic review is to summarize the current state of evidence of the implementation and outcomes of pediatric antimicrobial stewardship programs (ASPs) globally. Methods: MEDLINE, Embase and Cochrane Library databases were systematically searched to identify studies reporting on ASP in children aged 0-18 years and conducted in outpatient or in-hospital settings. Three investigators independently reviewed identified articles for inclusion and extracted relevant data. Results: Of the 41,916 studies screened, 113 were eligible for inclusion in this study. Most of the studies originated in the USA (52.2%), while a minority were conducted in Europe (24.7%) or Asia (17.7%). Seventy-four (65.5%) studies used a before-and-after design, and sixteen (14.1%) were randomized trials. The majority (81.4%) described in-hospital ASPs with half of interventions in mixed pediatric wards and ten (8.8%) in emergency departments. Only sixteen (14.1%) studies focused on the costs of ASPs. Almost all the studies (79.6%) showed a significant reduction in inappropriate prescriptions. Compliance after ASP implementation increased. Sixteen of the included studies quantified cost savings related to the intervention with most of the decreases due to lower rates of drug administration. Seven studies showed an increased susceptibility of the bacteria analysed with a decrease in extended spectrum beta-lactamase producers E. coli and K. pneumoniae; a reduction in the rate of P. aeruginosa carbapenem resistance subsequent to an observed reduction in the rate of antimicrobial days of therapy; and, in two studies set in outpatient setting, an increase in erythromycin-sensitive S. pyogenes following a reduction in the use of macrolides. Conclusions: Pediatric ASPs have a significant impact on the reduction of targeted and empiric antibiotic use, healthcare costs, and antimicrobial resistance in both inpatient and outpatient settings. Pediatric ASPs are now widely implemented in the USA, but considerable further adaptation is required to facilitate their uptake in Europe, Asia, Latin America and Africa
The RHIC Zero Degree Calorimeter
High Energy collisions of nuclei usually lead to the emission of evaporation
neutrons from both ``beam'' and ``target'' nuclei. At the RHIC heavy ion
collider with 100GeV/u beam energy, evaporation neutrons diverge by less than
milliradians from the beam axis Neutral beam fragments can be detected
downstream of RHIC ion collisions (and a large aperture Accelerator dipole
magnet) if 4 mr but charged fragments in the same angular range
are usually too close to the beam trajectory.
In this 'zero degree' region produced particles and other secondaries deposit
negligible energy when compared with that of beam fragmentation neutrons.
The purpose of the RHIC zero degree calorimeters (ZDC's) is to detect
neutrons emitted within this cone along both beam directions and measure their
total energy (from which we calculate multiplicity). The ZDC coincidence of the
2 beam directions is a minimal bias selection of heavy ion collisions. This
makes it useful as an event trigger and a luminosity monitor\cite{baltz} and
for this reason we built identical detectors for all 4 RHIC experiments.
The neutron multiplicity is also known to be correlated with event geometry
\cite{appel} and will be used to measure collision centrality in mutual beam
int eractions.Comment: 18 pages, 12 figure
Trigger, an active release experiment that stimulated auroral particle precipitation and wave emissions
The experiment design, including a description of the diagnostic and chemical release payload, and the general results are given for an auroral process simulation experiment. A drastic increase of the field aligned charged particle flux was observed over the approximate energy range 10 eV to more than 300 keV, starting about 150 ms after the release and lasting about one second. The is evidence of a second particle burst, starting one second after the release and lasting for tens of seconds, and evidence for a periodic train of particle bursts occurring with a 7.7 second period from 40 to 130 seconds after the release. A transient electric field pulse of 200 mv/m appeared just before the particle flux increase started. Electrostatic wave emissions around 2 kHz, as well as a delayed perturbation of the E-region below the plasma cloud were also observed. Some of the particle observations are interpreted in terms of field aligned electrostatic acceleration a few hundred kilometers above the injected plasma cloud. It is suggested that the acceleration electric field was created by an instability driven by field aligned currents originating in the plasma cloud
Controlled dephasing of Andreev states in superconducting quantum point-contacts
We have studied the relaxation and dephasing processes in a superconducting
quantum point contact induced by the interaction with an electromagnetic
environment. Based on a density matrix approach we obtain the rates for the
dissipative dynamics as function of the transmission, the phase difference on
the contact and the external impedance. Our calculation allows to determine the
appropriate range of parameters for the observation of coherent oscillations in
the current through the contact.Comment: 8 pages, 2 figures. To appear in Physical Review
Virus reactivations and serology patterns following first-line therapy with alemtuzumab or fludarabine-based combination therapy in patients with chronic lymphocytic leukemia
A new electrochemical method for the determination of chondroitin sulfate based on its supramolecular interaction with cupferron-lead(II) complex
In this paper, the interaction of cupferron (Cup) and lead (II) complex
[Cup-Pb (II)] with chondroitin sulfate (CS) was investigated by linear sweep
voltammetric method. In the selected medium of pH 5.5 (acetic acid-hexamine
buffer solution), Cup can interact with Pb (II) to form a stable complex of
[Cup-Pb(II)], which has a sensitive second order derivative polarographic
reductive peak at -0.64V (vs.SCE). After the addition of CS into Cup-Pb (II)
complex solution, the reductive peak current decreased without any shift of
the peak potential and no new peak appeared, which indicated that an
unelectroactive supramolecular complex of CS with [Cup-Pb(II)] was formed.
The binding reaction conditions were carefully investigated. Under the
optimal conditions, the interaction mechanism was discussed. The decrease of
reductive peak current was directly proportional to the CS concentration,
thus a new quantitative determination method for CS was established with the
linear regression equation as ΔIp″(nA)=36.97 C/mg L-1+12.45 (n=10, γ=0.995).
The effects of other substances on the determination were carefully
investigated and three synthetic samples were determined with satisfactory
results. The binding constant (βs) and the binding number (m) of CS with
[Cup-Pb(II)] complex were calculated from the voltammetric data with the
results as βs=1.89×1010 and m≈2.5
Polya's inequalities, global uniform integrability and the size of plurisubharmonic lemniscates
First we prove a new inequality comparing uniformly the relative volume of a
Borel subset with respect to any given complex euclidean ball \B \sub \C^n
with its relative logarithmic capacity in \C^n with respect to the same ball
\B.
An analoguous comparison inequality for Borel subsets of euclidean balls of
any generic real subspace of \C^n is also proved.
Then we give several interesting applications of these inequalities.
First we obtain sharp uniform estimates on the relative size of \psh
lemniscates associated to the Lelong class of \psh functions of logarithmic
singularities at infinity on \C^n as well as the Cegrell class of
\psh functions of bounded Monge-Amp\`ere mass on a hyperconvex domain \W
\Sub \C^n.
Then we also deduce new results on the global behaviour of both the Lelong
class and the Cegrell class of \psh functions.Comment: 25 page
Superconducting single-mode contact as a microwave-activated quantum interferometer
The dynamics of a superconducting quantum point contact biased at subgap
voltages is shown to be strongly affected by a microwave electromagnetic field.
Interference among a sequence of temporally localized, microwave-induced
Landau-Zener transitions between current carrying Andreev levels results in
energy absorption and in an increase of the subgap current by several orders of
magnitude. The contact is an interferometer in the sense that the current is an
oscillatory function of the inverse bias voltage. Possible applications to
Andreev-level spectroscopy and microwave detection are discussed
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