Pump power reduction by photodarkening in Yb-doped fibres

The influence of the photodarkening at a pump wavelength to envisage the direct impact of the photodarkening in the YDF based devices is reported. Results suggest that the photodarkening does not only induce excess background loss as commonly interpreted, but also influences pump efficiency

Two dimensional Berezin-Li-Yau inequalities with a correction term

We improve the Berezin-Li-Yau inequality in dimension two by adding a positive correction term to its right-hand side. It is also shown that the asymptotical behaviour of the correction term is almost optimal. This improves a previous result by Melas.Comment: 6 figure

Notes on contributors

The gas-phase complex UO2(TMOGA)(2)(2+) (TMOGA = tetramethyl-3-oxa-glutaramide) prepared by electrospray ionization was characterized by infrared multiphoton dissociation (IRMPD) spectroscopy. The IRMPD spectrum from 700-1800 cm(-1) was interpreted using a computational study based on density functional theory. The predicted vibrational frequencies are in good agreement with the measured values, with an average deviation of only 8 cm(-1) (<1%) and a maximum deviation of 21 cm(-1) (<2%). The only IR peak assigned to the linear uranyl moiety was the asymmetric v(3) mode, which appeared at 965 cm(-1) and was predicted by DFT as 953 cm(-1). This v(3) frequency is red-shifted relative to bare uranyl, UO22+, by ca. 150 cm(-1) due to electron donation from the TMOGA ligands. Based on the degree of red-shifting, it is inferred that two TMOGA oxygen-donor ligands have a greater effective gas basicity than the four monodentate acetone ligands in UO2(acetone)(4)(2+). The uranyl v(3) frequency was also computed for uranyl coordinated by two TMGA ligands, in which the central O-ether, of TMOGA has been replaced by CH2. The computed v(3) for UO2(TMGA)(2)(2+), 950 cm(-1), is essentially the same as that for UO2(TMOGA)(2)(2+), suggesting that electron donation to uranyl from the ether of TMOGA is minor. The computed v(3) asymmetric stretching frequencies for the three actinyl complexes, UO2(TMOGA)(2)(2+), NpO2(TMOGA)(2)(2+) and PuO2(TMOGA)(2)(2+), are comparable. This similarity is discussed in the context of the relationship between v(3) and intrinsic actinide-oxygen bond energies in actinyl complexes

Controlling the direction, topological charge, and spectrum of transition radiation with holographic metasurfaces

We show experimentally that wavefront - the direction, spectral composition and phase profile of light emission - stimulated by free electron injection into plasmonic and dielectric media can be controlled with high finesse using holographic nanostructures

Countable locally 2-arc-transitive bipartite graphs

We present an order-theoretic approach to the study of countably infinite locally 2-arc-transitive bipartite graphs. Our approach is motivated by techniques developed by Warren and others during the study of cycle-free partial orders. We give several new families of previously unknown countably infinite locally-2-arc-transitive graphs, each family containing continuum many members. These examples are obtained by gluing together copies of incidence graphs of semilinear spaces, satisfying a certain symmetry property, in a tree-like way. In one case we show how the classification problem for that family relates to the problem of determining a certain family of highly arc-transitive digraphs. Numerous illustrative examples are given.Comment: 29 page

Community Use of Physical and Occupational Therapy After Stroke and Risk of Hospital Readmission

Objectives To determine whether receipt of therapy and number and timing of therapy visits decreased hospital readmission risk in stroke survivors discharged home. Design Retrospective cohort analysis of Medicare claims (2010–2013). Setting Acute care hospital and community. Participants Patients hospitalized for stroke who were discharged home and survived the first 30 days (N=23,413; mean age ± SD, 77.6±7.5y). Interventions Physical and occupational therapist use in the home and/or outpatient setting in the first 30 days after discharge (any use, number of visits, and days to first visit). Main Outcome Measures Hospital readmission 30 to 60 days after discharge. Covariates included demographic characteristics, proxy variables for functional status, hospitalization characteristics, comorbidities, and prior health care use. Multivariate logistic regression analyses were conducted to examine the relation between therapist use and readmission. Results During the first 30 days after discharge, 31% of patients saw a therapist in the home, 11% saw a therapist in an outpatient setting, and 59% did not see a therapist. Relative to patients who had no therapist contact, those who saw an outpatient therapist were less likely to be readmitted to the hospital (odds ratio, 0.73; 95% confidence interval, 0.59–0.90). Although the point estimates did not reach statistical significance, there was some suggestion that the greater the number of therapist visits in the home and the sooner the visits started, the lower the risk of hospital readmission. Conclusions After controlling for observable demographic-, clinical-, and health-related differences, we found that individuals who received outpatient therapy in the first 30 days after discharge home after stroke were less likely to be readmitted to the hospital in the subsequent 30 days, relative to those who received no therapy

Longitudinal metabolic and gut bacterial profiling of pregnant women with previous bariatric surgery

Objective Due to the global increase in obesity rates and success of bariatric surgery in weight reduction, an increasing number of women now present pregnant with a previous bariatric procedure. This study investigates the extent of bariatric-associated metabolic and gut microbial alterations during pregnancy and their impact on fetal development. Design A parallel metabonomic (molecular phenotyping based on proton nuclear magnetic resonance spectroscopy) and gut bacterial (16S ribosomal RNA gene amplicon sequencing) profiling approach was used to determine maternal longitudinal phenotypes associated with malabsorptive/mixed (n=25) or restrictive (n=16) procedures, compared with women with similar early pregnancy body mass index but without bariatric surgery (n=70). Metabolic profiles of offspring at birth were also analysed. Results Previous malabsorptive, but not restrictive, procedures induced significant changes in maternal metabolic pathways involving branched-chain and aromatic amino acids with decreased circulation of leucine, isoleucine and isobutyrate, increased excretion of microbial-associated metabolites of protein putrefaction (phenylacetlyglutamine, p-cresol sulfate, indoxyl sulfate and p-hydroxyphenylacetate), and a shift in the gut microbiota. The urinary concentration of phenylacetylglutamine was significantly elevated in malabsorptive patients relative to controls (p=0.001) and was also elevated in urine of neonates born from these mothers (p=0.021). Furthermore, the maternal metabolic changes induced by malabsorptive surgery were associated with reduced maternal insulin resistance and fetal/birth weight. Conclusion Metabolism is altered in pregnant women with a previous malabsorptive bariatric surgery. These alterations may be beneficial for maternal outcomes, but the effect of elevated levels of phenolic and indolic compounds on fetal and infant health should be investigated further

Study of Distribution and Asymmetry of Solar Active Prominences During Solar Cycle 23

In this paper we present the results of a study of the spatial distribution and asymmetry of solar active prominences (SAP) for the period 1996-2007 (solar cycle 23). For more meaningful statistical analysis we have analysed the distribution and asymmetry of SAP in two subdivisions viz. Group1 (ADF, APR, DSF, CRN, CAP) and Group2 (AFS, ASR, BSD, BSL, DSD, SPY, LPS). The north-south (N-S) latitudinal distribution shows that the SAP events are most prolific in the 21-30degree slice in the northern and southern hemispheres and east-west (E-W) longitudinal distribution study shows that the SAP events are most prolific (best visible) in the 81-90degree slice in the eastern and western hemispheres. It has been found that the SAP activity during this cycle is low compared to previous solar cycles. The present study indicates that during the rising phase of the cycle the number of SAP events were roughly equal on the north and south hemispheres. However, activity on the southern hemisphere has been dominant since 1999. Our statistical study shows that the N-S asymmetry is more significant then the E-W asymmetry.Comment: 21 pages 5 figures; Published online; 02 October, 2009; Solar Physics Journa

Electron Backscatter Diffraction Analysis of the Microstructure Fineness in Pure Copper under Torsional Deformation

Torsional deformation is regarded a promising deformation procedure to prepare the gradient structural materials. Pure copper was subjected to large plastic strains in torsion. Electron backscatter diffraction analysis was used to explore the microstructure evolution. The observations demonstrate that both high-angle grain boundaries and misorientation increase with strain. The grains finer and more homogeneous. In addition, the microstructure within the shear band demonstrates a distinct preferred orientation. The crystal direction is parallel to the shear direction, and the crystal {111} inclines to the plane shear surface. A torsion-induced bar specimen includes a {011} brass texture, {011} Gaussian texture, and stronger {112} copper texture.Деформация кручения рассматривается как перспективный метод получения градиентных конструкционных материалов. Чистую медь подвергали большим пластическим деформациям при кручении. Для изучения микроструктурных изменений использован дифракционный анализ (EBSD). Показано, что большеугловые границы зерен и разориентировка увеличиваются с ростом степени деформации, зерна более мелкие и однородные. Микроструктура в полосе сдвига имеет выраженную преимущественную ориентировку. Направление кристалла параллельно направлению сдвига, а кристалл {111} наклонен к поверхности плоского сдвига. Брус, подвергнутый кручению, имеет латунную текстуру {011}, гауссову текстуру {011} и более прочную медную текстуру {112}

Physical and Occupational Therapy From the Acute to Community Setting After Stroke: Predictors of Use, Continuity of Care, and Timeliness of Care

Objective: To identify predictors of therapist use (any use, continuity of care, timing of care) in the acute care hospital and community (home or outpatient) for patients discharged home after stroke. Design: Retrospective cohort analysis of Medicare claims (2010–2013) linked to hospital-level and county-level data. Setting: Acute care hospital and community. Participants: Patients (N=23,413) who survived the first 30 days at home after being discharged from an acute care hospital after stroke. Interventions: Not applicable. Main Outcome Measures: Physical and occupational therapist use in acute care and community settings; continuity of care across the inpatient and home or the inpatient and outpatient settings; and early therapist use in the home or outpatient setting. Multivariate logistic and multinomial logistic regression analyses were conducted to identify hospital-level, county-level, and sociodemographic characteristics associated with therapist use, continuity, and timing, controlling for clinical characteristics. Results: Seventy-eight percent of patients received therapy in the acute care hospital, but only 40.8% received care in the first 30 days after discharge. Hospital nurse staffing was positively associated with inpatient and outpatient therapist use and continuity of care across settings. Primary care provider supply was associated with inpatient and outpatient therapist use, continuity of care, and early therapist care in the home and outpatient setting. Therapist supply was associated with continuity of care and early therapist use in the community. There was consistent evidence of sociodemographic disparities in therapist use. Conclusions: Therapist use after stroke varies in the community and for specific sociodemographic subgroups and may be underused. Inpatient nurse staffing levels and primary care provider supply were the most consistent predictors of therapist use, continuity of care, and early therapist use