418 research outputs found
Upper critical field divergence induced by mesoscopic phase separation in the organic superconductor (TMTSF)2ReO4
Due to the competition of two anion orders, (TMTSF)2ReO4, presents a phase
coexistence between semiconducting and metallic (superconducting) regions
(filaments or droplets) in a wide range of pressure. In this regime, the
superconducting upper critical field for H parallel to both c* and b' axes
present a linear part at low fields followed by a divergence above a cross-over
field. This cross-over corresponds to the 3D-2D decoupling transition expected
in filamentary or granular superconductors. The sharpness of the transition
also demonstrates that all filaments are of similar sizes and self organize in
a very ordered way. The distance between the filaments and their cross-section
are estimated.Comment: 4 pages, 4 figure
Greenhouse gas measurements from a UK network of tall towers: technical description and first results
A network of three tall tower measurement stations was set up in 2012 across the United Kingdom to expand measurements made at the long-term background northern hemispheric site, Mace Head, Ireland. Reliable and precise in situ greenhouse gas (GHG) analysis systems were developed and deployed at three sites in the UK with automated instrumentation measuring a suite of GHGs. The UK Deriving Emissions linked to Climate Change (UK DECC) network uses tall (165â230âŻm) open-lattice telecommunications towers, which provide a convenient platform for boundary layer trace gas sampling. In this paper we describe the automated measurement system and first results from the UK DECC network for CO2, CH4, N2O, SF6, CO and H2. CO2 and CH4 are measured at all of the UK DECC sites by cavity ring-down spectroscopy (CRDS) with multiple inlet heights at two of the three tall tower sites to assess for boundary layer stratification. The short-term precisions (1Ï on 1âŻmin means) of CRDS measurements at background mole fractions for January 2012 to September 2015 is <âŻ0.05âŻÂ”molâŻmolâ1 for CO2 and <âŻ0.3âŻnmolâŻmolâ1 for CH4. Repeatability of standard injections (1Ï) is <âŻ0.03âŻÂ”molâŻmolâ1 for CO2 and <âŻ0.3âŻnmolâŻmolâ1 for CH4 for the same time period. N2O and SF6 are measured at three of the sites, and CO and H2 measurements are made at two of the sites, from a single inlet height using gas chromatography (GC) with an electron capture detector (ECD), flame ionisation detector (FID) or reduction gas analyser (RGA). Repeatability of individual injections (1Ï) on GC and RGA instruments between January 2012 and September 2015 for CH4, N2O, SF6, CO and H2 measurements were <âŻ2.8âŻnmolâŻmolâ1, <âŻ0.4âŻnmolâŻmolâ1, <âŻ0.07âŻpmolâŻmolâ1, <âŻ2âŻnmolâŻmolâ1 and <âŻ3âŻnmolâŻmolâ1, respectively. Instrumentation in the network is fully automated and includes sensors for measuring a variety of instrumental parameters such as flow, pressures, and sampling temperatures. Automated alerts are generated and emailed to site operators when instrumental parameters are not within defined set ranges. Automated instrument shutdowns occur for critical errors such as carrier gas flow rate deviations. Results from the network give good spatial and temporal coverage of atmospheric mixing ratios within the UK since early 2012. Results also show that all measured GHGs are increasing in mole fraction over the selected reporting period and, except for SF6, exhibit a seasonal trend. CO2 and CH4 also show strong diurnal cycles, with night-time maxima and daytime minima in mole fractions
Assessing the perceptions of pharmacists working in Lebanese hospitals on the continuing education preferences
Background: Continuing education (CE) is an international tool that requires lifelong active participation in learning activities allowing the pharmacist to stay a major player among others. In 2014 the CE program was introduced to the pharmacists licensed in Lebanon as a mandatory requirement for re-licensure. In the absence of guidelines regarding the quality and quantity of CE programs, behavioral resistance to precipitate in the CE programs might be encountered among the pharmacists.
Objective: The objective of this study is to assess the perceptions of pharmacists working in Lebanese hospitals on the continuing education preferences. The advantage of this program is to collect information that would help the Order of Pharmacy in Lebanon to upgrade the CE program in a way that is more acceptable and convenient for the pharmacists.
Methods: A cross-sectional study was carried out in 2016, using a proportionate random sample of Lebanese hospital pharmacies from all governorates in Lebanon. A structured questionnaire was distributed to all hospital pharmacies in Lebanon. Descriptive statistics were calculated for all study variables. This includes the mean and standard deviation for continuous measures, counts and percentages for categorical variables
Results: A total of 107 (53.5%) participants completed the questionnaires. The majority of participants were from Beirut and Mount Lebanon. The percentage of participants working at private hospitals was (68.2%).The majority of participants who completed the questionnaire (86.2%) agreed that continuing education programs affects their way of practice and increases their knowledge. Their preferred CE types to be used in the future were the computer based ones (60.6%), interactive workshops (45.5%) and printed materials (44.9%). Their considerations for selecting the CE type is based on their interest in the topic (80.6%), the ease of access to print or online material (77.2%), or the convenience of being offered during an event (67.1%). Participants noted that barriers to attend live CEs were mainly work responsibilities (76%), travel distance (65.6%), family commitments (48.4%) and scheduling (40.6%).
Conclusions: Lebanese hospital pharmacists are highly committed to CE. They consider it a practical tool for career development and advancement
Lateral Distribution of Muons in IceCube Cosmic Ray Events
In cosmic ray air showers, the muon lateral separation from the center of the
shower is a measure of the transverse momentum that the muon parent acquired in
the cosmic ray interaction. IceCube has observed cosmic ray interactions that
produce muons laterally separated by up to 400 m from the shower core, a factor
of 6 larger distance than previous measurements. These muons originate in high
pT (> 2 GeV/c) interactions from the incident cosmic ray, or high-energy
secondary interactions. The separation distribution shows a transition to a
power law at large values, indicating the presence of a hard pT component that
can be described by perturbative quantum chromodynamics. However, the rates and
the zenith angle distributions of these events are not well reproduced with the
cosmic ray models tested here, even those that include charm interactions. This
discrepancy may be explained by a larger fraction of kaons and charmed
particles than is currently incorporated in the simulations
The IceCube Neutrino Observatory Part VI: Ice Properties, Reconstruction and Future Developments
Papers on ice properties, reconstruction and future developments submitted to
the 33nd International Cosmic Ray Conference (Rio de Janeiro 2013) by the
IceCube Collaboration.Comment: 28 pages, 38 figures; Papers submitted to the 33nd International
Cosmic Ray Conference, Rio de Janeiro 2013; version 2 corrects errors in the
author lis
Search for Relativistic Magnetic Monopoles with IceCube
We present the first results in the search for relativistic magnetic
monopoles with the IceCube detector, a subsurface neutrino telescope located in
the South Polar ice cap containing a volume of 1 km. This analysis
searches data taken on the partially completed detector during 2007 when
roughly 0.2 km of ice was instrumented. The lack of candidate events
leads to an upper limit on the flux of relativistic magnetic monopoles of
\Phi_{\mathrm{90%C.L.}}\sim 3\e{-18}\fluxunits for . This is a
factor of 4 improvement over the previous best experimental flux limits up to a
Lorentz boost below . This result is then interpreted for a
wide range of mass and kinetic energy values.Comment: 11 pages, 11 figures. v2 is minor text edits, no changes to resul
An improved method for measuring muon energy using the truncated mean of dE/dx
The measurement of muon energy is critical for many analyses in large
Cherenkov detectors, particularly those that involve separating
extraterrestrial neutrinos from the atmospheric neutrino background. Muon
energy has traditionally been determined by measuring the specific energy loss
(dE/dx) along the muon's path and relating the dE/dx to the muon energy.
Because high-energy muons (E_mu > 1 TeV) lose energy randomly, the spread in
dE/dx values is quite large, leading to a typical energy resolution of 0.29 in
log10(E_mu) for a muon observed over a 1 km path length in the IceCube
detector. In this paper, we present an improved method that uses a truncated
mean and other techniques to determine the muon energy. The muon track is
divided into separate segments with individual dE/dx values. The elimination of
segments with the highest dE/dx results in an overall dE/dx that is more
closely correlated to the muon energy. This method results in an energy
resolution of 0.22 in log10(E_mu), which gives a 26% improvement. This
technique is applicable to any large water or ice detector and potentially to
large scintillator or liquid argon detectors.Comment: 12 pages, 16 figure
Carbon monoxide and respiratory symptoms in young adult passive smokers: A pilot study comparing waterpipe to cigarette
Objectives: Studies have correlated second hand smoke (SHS) with many diseases, especially respiratory effects. The goal of this study was to measure the impact of SHS on the respiratory symptoms and exhaled carbon monoxide. Material and Methods: The study population consisted of 50 young workers in restaurants serving waterpipes, 48 university students who sit frequently in the university cafeteria where cigarette smoking is allowed and 49 university students spending time in places where smoking is not allowed. Subjects completed questionnaires on socio-demographic characteristics, respiratory symptoms and exposure to SHS. Exhaled carbon monoxide levels were measured. ANOVA and Chi-square tests were used when applicable as well as linear and logistic regression analysis. Results: Exposure to cigarette smoke in university (adjusted odds ratio (ORa) = 6.06) and occupational exposure to waterpipe smoke (ORa = 7.08) were predictors of chronic cough. Being married (ORa = 6.40), living near a heavy traffic road (ORa = 9.49) or near a local power generator (ORa = 7.54) appeared responsible for chronic sputum production. Moreover, predictors of chronic allergies were: being male (ORa = 7.81), living near a local power generator (ORa = 5.52) and having a family history of chronic respiratory diseases (ORa = 17.01). Carbon monoxide levels were augmented by the number of weekly hours of occupational exposure to waterpipe smoke (ÎČ = 1.46) and the number of daily hours of exposure to cigarette smoke (ÎČ = 1.14). Conclusions: In summary, young non-smoker subjects demonstrated more chronic cough and elevated carbon monoxide levels when exposed to SHS while the effect of waterpipe was even more evident
- âŠ