Neutron and X-ray scattering experiments on lithium polymer electrolytes

The authors are carrying out structural, dynamical and transport measurements of lithium polymer electrolytes, in order to provide information needed to improve the performance of secondary lithium battery systems. Microscopically, they behave as liquids under conditions of practical interest. Development of batteries based on these materials has focused on rechargeable systems with intercalation/insertion cathodes and lithium or lithium-containing materials as anodes. The electrolytes are generally composites of a polyethylene oxide (PEO) or another modified polyether and a salt such as LiClO{sub 4}, LiAsF{sub 6} or LiCF{sub 3}SO{sub 3}. Research on electrolyte materials for lithium batteries has focused on synthesis, characterization, and development of practical devices. Some characterization work has been carried out to determine the properties of the ion polymer and ion interactions, principally through spectroscopic, thermodynamic and transport measurements. It is generally believed that ionic conduction is a property of the amorphous phase of these materials. It is also believed that ion association, ion polymer interactions and local relaxations of the polymer strongly influence the ionic mobility. However, much about the nature of the charge carriers, the ion association processes, and the ion polymer interactions and the role that these play in the ionic conductivity of the electrolytes remains unknown. The authors have initiated a combined experimental and theoretical study of the structure and dynamics of lithium polymer electrolytes. They plan to investigate the effects of the polymer host on ion solvation and the attendant effects of ion pairing, which affect the ionic transport in these systems

Phase transition in the transverse Ising model using the extended coupled-cluster method

The phase transition present in the linear-chain and square-lattice cases of the transverse Ising model is examined. The extended coupled cluster method (ECCM) can describe both sides of the phase transition with a unified approach. The correlation length and the excitation energy are determined. We demonstrate the ability of the ECCM to use both the weak- and the strong-coupling starting state in a unified approach for the study of critical behavior.Comment: 10 pages, 7 eps-figure

Non-linear instability of Kerr-type Cauchy horizons

Using the general solution to the Einstein equations on intersecting null surfaces developed by Hayward, we investigate the non-linear instability of the Cauchy horizon inside a realistic black hole. Making a minimal assumption about the free gravitational data allows us to solve the field equations along a null surface crossing the Cauchy Horizon. As in the spherical case, the results indicate that a diverging influx of gravitational energy, in concert with an outflux across the CH, is responsible for the singularity. The spacetime is asymptotically Petrov type N, the same algebraic type as a gravitational shock wave. Implications for the continuation of spacetime through the singularity are briefly discussed.Comment: 11 pages RevTeX, two postscript figures included using epsf.st

Runaway Events Dominate the Heavy Tail of Citation Distributions

Statistical distributions with heavy tails are ubiquitous in natural and social phenomena. Since the entries in heavy tail have disproportional significance, the knowledge of its exact shape is very important. Citations of scientific papers form one of the best-known heavy tail distributions. Even in this case there is a considerable debate whether citation distribution follows the log-normal or power-law fit. The goal of our study is to solve this debate by measuring citation distribution for a very large and homogeneous data. We measured citation distribution for 418,438 Physics papers published in 1980-1989 and cited by 2008. While the log-normal fit deviates too strong from the data, the discrete power-law function with the exponent $\gamma=3.15$ does better and fits 99.955% of the data. However, the extreme tail of the distribution deviates upward even from the power-law fit and exhibits a dramatic "runaway" behavior. The onset of the runaway regime is revealed macroscopically as the paper garners 1000-1500 citations, however the microscopic measurements of autocorrelation in citation rates are able to predict this behavior in advance.Comment: 6 pages, 5 Figure

Calibration of Tuffak polycarbonate track detector for identification of relativistic nuclei

We discuss response of Tuffak polycarbonate to relativistic heavy nuclei using two methods, measurement of the minor axis diameter and of the length of the track cone, to determine charge resolution. At Z = 92 (0.95 GeV/u 238U) both methods give about 0.9e charge resolution for a single cone measurement. Multiple cone measurements along the ion's trajectory have yielded a charge resolution [sigma]z [les] 0.25e (16 cones) when stripping foils (Cu) are interleaved between plastic sheets to minimize sheet-to-sheet charge state correlations. As the charge of the incident ion decreases to Z [approximate] 52-57, the single-cone charge resolution improves ([sigma]z ~ 0.29e). The angular response of Tuffak is fairly constant for zenith angles of incidence from 0[deg] to 48[deg]. Range measurements of stopping relativistic 238U in Tuffak deviate by ~5% from that predicted by the Bethe-Bloch formula, as expected from recent relativistic calculations. We conclude that Tuffak is an excellent track detector for identification of nuclear charges of relativistic heavy nuclei with 50 Z <= 92.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24979/1/0000406.pd

Search for the Proton Decay Mode proton to neutrino K+ in Soudan 2

We have searched for the proton decay mode proton to neutrino K+ using the one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0. We found one candidate event consistent with background, yielding a limit, tau/B > 4.3 10^{31} years at 90% CL with no background subtraction.Comment: 13 pages, Latex, 3 tables and 3 figures, Accepted by Physics Letters

Stratification of COPD patients by previous admission for targeting of preventative care

SummaryBackgroundHospital admissions for exacerbations of chronic obstructive pulmonary disease (COPD) impact considerably on disease evolution and healthcare provision. Building on previous studies, this study postulated that COPD patients could be stratified by risk of admission to determine which groups provide the greatest burden on resources, and how interventions should be targeted to prevent admissions.MethodsCOPD admissions during 1997–2003 in three Strategic Health Authorities in England were analysed (n=80,291). Patients admitted during winter (1 November–31 March) were stratified into three groups according to the number of admissions during the previous year: 0 (NIL), 1–2 (MOD) or ≥3 (FRQ). Winter weeks were classified as “average”, “above average”, “high”, or “very high” risk, compared with the long-term mean.ResultsThe risk of admission during winter for FRQ and MOD patients was 40% and 12% respectively. NIL patients contributed to 70% of winter admissions, and 90% of the variation between “average” and “very high” weeks, versus 9% and 1% for MOD and FRQ.ConclusionsPatients with no previous admissions have lower individual risk, but contribute to a high overall utilisation of health care resources and should be targeted to prevent admissions. Focusing upon high-risk patients (frequent attenders or more severe) may only reduce a small proportion of admissions, and therefore clinicians should ensure that all COPD patients receive appropriate therapy to reduce risk of exacerbations

Association Between Schizophrenia-Related Polygenic Liability and the Occurrence and Level of Mood-Incongruent Psychotic Symptoms in Bipolar Disorder

Importance Bipolar disorder (BD) overlaps schizophrenia in its clinical presentation and genetic liability. Alternative approaches to patient stratification beyond current diagnostic categories are needed to understand the underlying disease processes/mechanisms. Objectives To investigate the relationship between common-variant liability for schizophrenia, indexed by polygenic risk scores (PRS) and psychotic presentations of BD, using clinical descriptions which consider both occurrence and level of mood-incongruent psychotic features. Design Case-control design: using multinomial logistic regression, to estimate differential associations of PRS across categories of cases and controls. Settings & Participants 4399 BD cases, 2966 (67%) female, mean age-at-interview 46 [sd 12] years, from the BD Research Network (BDRN) were included in the final analyses. For comparison genotypic data for 4976 schizophrenia cases and 9012 controls from the Type-1 diabetes genetics consortium and Generation Scotland were included. Exposure Standardised PRS, calculated using alleles with an association p-value threshold < 0.05 in the second Psychiatric Genomics Consortium genome-wide association study of schizophrenia, adjusted for the first 10 population principal components and genotyping-platform. Main outcome measure Multinomial logit models estimated PRS associations with BD stratified by (1) Research Diagnostic Criteria (RDC) BD subtypes (2) Lifetime occurrence of psychosis.(3) Lifetime mood-incongruent psychotic features and (4) ordinal logistic regression examined PRS associations across levels of mood-incongruence. Ratings were derived from the Schedule for Clinical Assessment in Neuropsychiatry interview (SCAN) and the Bipolar Affective Disorder Dimension Scale (BADDS). Results Across clinical phenotypes, there was an exposure-response gradient with the strongest PRS association for schizophrenia (RR=1.94, (95% C.I. 1.86, 2.01)), then schizoaffective BD (RR=1.37, (95% C.I. 1.22, 1.54)), BD I (RR= 1.30, (95% C.I. 1.24, 1.36)) and BD II (RR=1.04, (95% C.I. 0.97, 1.11)). Within BD cases, there was an effect gradient, indexed by the nature of psychosis, with prominent mood-incongruent psychotic features having the strongest association (RR=1.46, (95% C.I. 1.36, 1.57)), followed by mood-congruent psychosis (RR= 1.24, (95% C.I. 1.17, 1.33)) and lastly, BD cases with no history of psychosis (RR=1.09, (95% C.I. 1.04, 1.15)). Conclusion We show for the first time a polygenic-risk gradient, across schizophrenia and bipolar disorder, indexed by the occurrence and level of mood-incongruent psychotic symptoms

Results of the Search for Strange Quark Matter and Q-balls with the SLIM Experiment

The SLIM experiment at the Chacaltaya high altitude laboratory was sensitive to nuclearites and Q-balls, which could be present in the cosmic radiation as possible Dark Matter components. It was sensitive also to strangelets, i.e. small lumps of Strange Quark Matter predicted at such altitudes by various phenomenological models. The analysis of 427 m^2 of Nuclear Track Detectors exposed for 4.22 years showed no candidate event. New upper limits on the flux of downgoing nuclearites and Q-balls at the 90% C.L. were established. The null result also restricts models for strangelets propagation through the Earth atmosphere.Comment: 14 pages, 11 EPS figure

Measurement of a small atmospheric νμ/νe\nu_\mu/\nu_e ratio

From an exposure of 25.5~kiloton-years of the Super-Kamiokande detector, 900 muon-like and 983 electron-like single-ring atmospheric neutrino interactions were detected with momentum $p_e > 100$ MeV/$c$, $p_\mu > 200$ MeV/$c$, and with visible energy less than 1.33 GeV. Using a detailed Monte Carlo simulation, the ratio $(\mu/e)_{DATA}/(\mu/e)_{MC}$ was measured to be $0.61 \pm 0.03(stat.) \pm 0.05(sys.)$, consistent with previous results from the Kamiokande, IMB and Soudan-2 experiments, and smaller than expected from theoretical models of atmospheric neutrino production.Comment: 14 pages with 5 figure