Stirring the Embers: High Sensitivity VLBI Observations of GRB030329

We present high sensitivity Very Long Baseline Interferometry (VLBI) observations 806 days after the gamma-ray burst of 2003 March 29 (GRB030329). The angular diameter of the radio afterglow is measured to be 0.347 +- 0.09 mas, corresponding to 0.99 +- 0.26 pc at the redshift of GRB030329 (z = 0.1685). The evolution of the image size favors a uniform external density over an R^-2 wind-like density profile (at distances of R >~10^18 cm from the source), although the latter cannot be ruled out yet. The current apparent expansion velocity of the image size is only mildly relativistic, suggesting a non-relativistic transition time of t_NR ~ 1 yr. A rebrightening, or at least a significant flattening in the flux decay, is expected within the next several years as the counter-jet becomes visible (this has not yet been observed). An upper limit of <1.9c is set on the proper motion of the flux centroid.Comment: 16 pages, 5 figures, accepted for publication in Astrophysical Journa

3d polyaniline nanofibers anchored on carbon paper for high-performance and light-weight supercapacitors

In the field of advanced energy storage, nanostructured Polyaniline (PANI) based materials hold a special place. Extensive studies have been done on the application of PANI in supercapacitors, however, the structure–property relationship of these materials is still not understood. This paper presents a detailed characterization of the novel sodium phytate doped 3D PANI nanofibers anchored on different types of carbon paper for application in supercapacitors. An excellent relationship between the structures and properties of the synthesized samples was found. Remarkable energy storage characteristics with low values of solution, charge transfer and polarization resistance and a specific capacitance of 1106.9 ± 1.5 F g$^{−1}$ and 779 ± 2.6 F g$^{−1}$ at current density 0.5 and 10 Ag$^{−1}$, respectively, was achieved at optimized conditions. The symmetric supercapacitor assembly showed significant enhancement in both energy density and power density. It delivered an energy density of 95 Wh kg$^{−1}$ at a power of 846 W kg$^{−1}$. At a high-power density of 16.9 kW kg$^{−1}$, the energy density can still be kept at 13 Wh kg$^{−1}$. Cyclic stability was also checked for 1000 cycles at a current density of 10 Ag$^{−1}$ having excellent retention, i.e., 96%

PROMIS MCID and SCB Achievement in Rotator Cuff Repair

The purpose of this study was to establish threshold score changes to determine minimal clinically important difference (MCID) and substantial clinical benefit (SCB) in PROMIS computer adaptive test (CAT) scores following rotator cuff repair (RCR). Patients undergoing arthroscopic RCR were identified over a 24-month period. PROMIS CAT forms for upper extremity physical function (PROMIS-UE), pain interference (PROMIS-PI), and depression (PROMIS-D) were utilized. Analysis of variance testing with post hoc least significant difference pairwise comparisons and Tukey’s B subset analysis were used in determining if anchor question responses showed statistically significant differences between answers. These findings were used to establish two clinically significant outcome (CSO) groups, MCID and substantial clinical benefit (SCB). Patients were then dichotomized into two separate analyses, no MCID achievement compared with MCID achievement and no SCB achievement compared with SCB achievement. Of the 198 eligible patients, 168 patients (84.8%) were included in analysis. Receiver operating curve analysis determined delta PROMIS-UE values of 5.8 and 9.7 (area under the curve (AUC) = 0.906 and 0.949, respectively) and delta PROMIS-PI values of -11.4 and -12.9 (AUC = 0.875 and 0.938, respectively) to be excellent threshold predictors of MCID and SCB achievement. On average, 81.1%, 65.0%, and 54.5% of patients achieved MCID for PROMIS-UE, PROMIS-PI, and PROMIS-D while 70.7%, 60.7%, and 37.7% of patients in the cohort respectively achieved SCB

Improving water productivity, reducing poverty and enhancing equity in mixed crop-livestock systems in the Indo-Gangetic Basin

The “Improving water productivity, reducing poverty and enhancing equity in mixed crop-livestock systems in the Indo-Gangetic Basin” was designed and conducted by the International Water Management Institute (IWMI), in partnership with international and national partners, to address the relative neglect of livestock water needs of crop-livestock farming systems. The primary objective of this project was to optimize the productive use of water in the crop-livestock farming systems of semi-arid areas to enhance livelihoods, reduce poverty, contribute to gender equity, and protect the environment. This was addressed through an integrated approach led by a multi-disciplinary team across three States of the Ganga Basin

Exploring the factors affecting MOOC retention: a survey study

Massive Open Online Courses (MOOCs) hold the potential to open up educational opportunities to a global audience. However, evidence suggests that only a small proportion of MOOC participants go on to complete their courses and relatively little is understood about the MOOC design and implementation factors that influence retention. This paper reports a survey study of 379 participants enrolled at university in Cairo who were encouraged to take a MOOC of their own choice as part of their development. 122 participants (32.2%) went onto to complete an entire course. There were no significant differences in completion rates by gender, level of study (undergraduate or postgraduate) or MOOC platform. A post-MOOC survey of students’ perceptions found that MOOC Course Content was a significant predictor of MOOC retention, with the relationship mediated by the effect of content on the Perceived Effectiveness of the course. Interaction with the instructor of the MOOC was also found to be significant predictor of MOOC retention. Overall these constructs explained 79% of the variance in MOOC retention

Quantum corrections to the Pekar asymptotics of a strongly coupled polaron

We consider the Fr\"ohlich polaron model in the strong coupling limit. It is well known that to leading order the ground state energy is given by the (classical) Pekar energy. In this work, we establish the subleading correction, describing quantum fluctuation about the classical limit. Our proof applies to a model of a confined polaron, where both the electron and the polarization field are restricted to a set of finite volume, with linear size determined by the natural length scale of the Pekar problem.Comment: LaTeX, 40 pages; final version, to appear in Commun. Pure. Appl. Mat

A geophysical study of Mesquite Valley: Nevada-California border

This paper reports the results of a geophysical investigation of a sedimentary basin, Mesquite Valley, and its surrounding area in the Basin and Range province of the western United States. Mesquite Valley is located about 40 km south-southwest of Las Vegas, Nevada, and straddles the border between Nevada and California (Figure 1). It is surrounded on three sides by mountains in which Paleozoic sedimentary rocks and Precambrian granites and gneisses crop out (Figure 1) [Burchfiel et al., 1974; Durchfiel and Davis, 1971; Hewett, 1956]. Unlike most basins in the Basin and Range province, however, there are no clearly active, range-bounding normal faults, and, in general, the surrounding topography is more subdued than in the regions farther west or north

Policy Recommendations for Meeting the Grand Challenge to Achieve Equal Opportunity and Justice

This brief was created forSocial Innovation for America’s Renewal, a policy conference organized by the Center for Social Development in collaboration with the American Academy of Social Work & Social Welfare, which is leading theGrand Challenges for Social Work initiative to champion social progress. The conference site includes links to speeches, presentations, and a full list of the policy briefs