Study of dopants for radiation-resistant silicon Final report

Radiation effects on electrical properties of both aluminum and lithium doped bulk silico

Damage coefficients in low resistivity silicon

Electron and proton damage coefficients are determined for low resistivity silicon based on minority-carrier lifetime measurements on bulk material and diffusion length measurements on solar cells. Irradiations were performed on bulk samples and cells fabricated from four types of boron-doped 0.1 ohm-cm silicon ingots, including the four possible combinations of high and low oxygen content and high and low dislocation density. Measurements were also made on higher resistivity boron-doped bulk samples and solar cells. Major observations and conclusions from the investigation are discussed

Landau-Khalatnikov-Fradkin Transformations and the Fermion Propagator in Quantum Electrodynamics

We study the gauge covariance of the massive fermion propagator in three as well as four dimensional Quantum Electrodynamics (QED). Starting from its value at the lowest order in perturbation theory, we evaluate a non-perturbative expression for it by means of its Landau-Khalatnikov-Fradkin (LKF) transformation. We compare the perturbative expansion of our findings with the known one loop results and observe perfect agreement upto a gauge parameter independent term, a difference permitted by the structure of the LKF transformations.Comment: 9 pages, no figures, uses revte

The use of large artificial reefs to enhance fish populations at different depths in the Florida Keys

This study showed that large prefabricated units and concrete rubble patch reefs, placed as artificial marine habitats on sand bottom, greatly enhance the abundance, diversity, and biomass of fish in an area. Densities of individuals and biomass were found considerably higher at artificial reefs than at nearby, natural, bank reefs, a result consistent with other studies. Location, depth, and vertical profile are important factors determining fish assemblages at artificial habitats in the Keys. Fishes were both produced at artificial reefs and attracted from the surrounding area. Fish assemblages at the Hawk Channel artificial reefs were considerably different from those on the offshore reef tract, particularly in terms of dominant species. Rescue of the original 1992 work in 2005 was funded by the South Florida Ecosystem Restoration Prediction and Modeling Program

Effectiveness of a brief lifestyle intervention targeting mental health staff: analysis of physical fitness and activity in the Keeping Our Staff in Mind study.

BackgroundPeople with mental illness die on average 15 years less than the general population, primarily to cardiometabolic disease. Lifestyle interventions are effective in reducing cardiometabolic risk but are not routinely provided to mental health consumers. Lifestyle interventions targeting mental health staff may be beneficial in changing culture surrounding physical health and subsequently improving consumer outcomes. This study examines exercise and fitness outcomes of a targeted lifestyle intervention directed at Australian mental health staff.MethodsA pragmatic single-arm intervention study was conducted within an Australian public mental health service. Mental health staff were provided a five-session individualised lifestyle intervention (incorporating exercise and nutritional counselling) over 5 weeks. Two waves of the programme were delivered between 2015 and 2016. This paper examines the exercise and fitness outcomes of the second wave of the study. Participants were assessed at baseline and at a 16-week follow-up. The primary exercise outcome was a measurement of cardiorespiratory fitness. Secondary outcomes included self-reported physical activity and a measurement of handgrip strength.ResultsA total of 106 staff participated in this component of the study. Cardiorespiratory fitness increased significantly from baseline to follow-up (pConclusionLifestyle interventions incorporating exercise counselling may improve the physical health of mental health staff. Such strategies may be effective in improving culture surrounding physical health and/or increasing the effectiveness of lifestyle interventions targeting mental health consumers

Machine learning utilising spectral derivative data improves cellular health classification through hyperspectral infra-red spectroscopy

The objective differentiation of facets of cellular metabolism is important for several clinical applications, including accurate definition of tumour boundaries and targeted wound debridement. To this end, spectral biomarkers to differentiate live and necrotic/apoptotic cells have been defined using in vitro methods. The delineation of different cellular states using spectroscopic methods is difficult due to the complex nature of these biological processes. Sophisticated, objective classification methods will therefore be important for such differentiation. In this study, spectral data from healthy/traumatised cell samples using hyperspectral imaging between 2500-3500 nm were collected using a portable prototype device. Machine learning algorithms, in the form of clustering, have been performed on a variety of pre-processing data types including 'raw' unprocessed, smoothed resampling, background subtracted and spectral derivative. The resulting clusters were utilised as a diagnostic tool for the assessment of cellular health and quantified using both sensitivity and specificity to compare the different analysis methods. The raw data exhibited differences for one of the three different trauma types applied, although unable to accurately cluster all the traumatised samples due to signal contamination from the chemical insult. The background subtracted and smoothed data sets reduced the accuracy further, due to the apparent removal of key spectral features which exhibit cellular health. However, the spectral derivative data-types significantly improved the accuracy of clustering compared to other data types, with both sensitivity and specificity for the background subtracted data set being >94% highlighting its utility to account for unknown signal contamination while maintaining important cellular spectral features

Baryon Binding Energy in Sakai-Sugimoto Model

The binding energy of baryon has been studied in the dual $AdS_5\times S^5$ string theory with a black hole interior. In this picture baryon is constructed of a $D_5$ brane vertex wrapping on $S^5$ and $N_c$ fundamental strings connected to it. Here, we calculate the baryon binding energy in Sakai-Sugimoto model with a $D_4/D_8/\bar{D_8}$ in which the supersymmetry is completely broken. Also we check the $T$ dependence of the baryon binding energy. We believe that this model represents an accurate description of baryons due to the existence of Chern-Simones coupling with the gauge field on the brane. We obtain an analytical expression for the baryon binding energy . In that case we plot the baryon binding energy in terms of radial coordinate. Then by using the binding energy diagram, we determine the stability range for baryon configuration. And also the position and energy of the stable equilibrium point is obtained by the corresponding diagram. Also we plot the baryon binding energy in terms of temperature and estimate a critical temperature in which the baryon would be dissociated.Comment: 14 pages, 1 fi

The Relationship Between Stellar Light Distributions of Galaxies and their Formation Histories

A major problem in extragalactic astronomy is the inability to distinguish in a robust, physical, and model independent way how galaxy populations are related to each other and to their formation histories. A similar, but distinct, and also long standing question is whether the structural appearances of galaxies, as seen through their stellar light distributions, contain enough physical information to offer this classification. We argue through the use of 240 images of nearby galaxies that three model independent parameters measured on a single galaxy image reveal its major ongoing and past formation modes, and can be used as a robust classification system. These parameters quantitatively measure: the concentration (C), asymmetry (A) and clumpiness (S) of a galaxy's stellar light distribution. When combined into a three dimensional `CAS' volume all major classes of galaxies in various phases of evolution are cleanly distinguished. We argue that these three parameters correlate with important modes of galaxy evolution: star formation and major merging activity. This is argued through the strong correlation of Halpha equivalent width and broad band colors with the clumpiness parameter, the uniquely large asymmetries of 66 galaxies undergoing mergers, and the correlation of bulge to total light ratios, and stellar masses, with the concentration index. As an obvious goal is to use this system at high redshifts to trace evolution, we demonstrate that these parameters can be measured, within a reasonable and quantifiable uncertainty, with available data out to z ~ 3 using the Hubble Space Telescope GOODS ACS and Hubble Deep Field images.Comment: ApJS, in press, 30 pages, Figures 15 and 16 are in color. For a full resolution version, please go to http://www.astro.caltech.edu/~cc/cas.p

Antibody response to pneumococcal and influenza vaccination in patients with rheumatoid arthritis receiving abatacept

Background Patients with rheumatoid arthritis (RA), including those treated with biologics, are at increased risk of some vaccine-preventable infections. We evaluated the antibody response to standard 23-valent pneumococcal polysaccharide vaccine (PPSV23) and the 2011–2012 trivalent seasonal influenza vaccine in adults with RA receiving subcutaneous (SC) abatacept and background disease-modifying anti-rheumatic drugs (DMARDs). Methods Two multicenter, open-label sub-studies enrolled patients from the ACQUIRE (pneumococcal and influenza) and ATTUNE (pneumococcal) studies at any point during their SC abatacept treatment cycle following completion of ≥3 months’ SC abatacept. All patients received fixed-dose abatacept 125 mg/week with background DMARDs. A pre-vaccination blood sample was taken, and after 28 ± 3 days a final post- vaccination sample was collected. The primary endpoint was the proportion of patients achieving an immunologic response to the vaccine at Day 28 among patients without a protective antibody level to the vaccine antigens at baseline (pneumococcal: defined as ≥2-fold increase in post-vaccination titers to ≥3 of 5 antigens and protective antibody level of ≥1.6 μg/mL to ≥3 of 5 antigens; influenza: defined as ≥4-fold increase in post-vaccination titers to ≥2 of 3 antigens and protective antibody level of ≥1:40 to ≥2 of 3 antigens). Safety and tolerability were evaluated throughout the sub-studies. Results Pre- and post-vaccination titers were available for 113/125 and 186/191 enrolled patients receiving the PPSV23 and influenza vaccine, respectively. Among vaccinated patients, 47/113 pneumococcal and 121/186 influenza patients were without protective antibody levels at baseline. Among patients with available data, 73.9 % (34/46) and 61.3 % (73/119) met the primary endpoint and achieved an immunologic response to PPSV23 or influenza vaccine, respectively. In patients with pre- and post-vaccination data available, 83.9 % in the pneumococcal study demonstrated protective antibody levels with PPSV23 (titer ≥1.6 μg/mL to ≥3 of 5 antigens), and 81.2 % in the influenza study achieved protective antibody levels (titer ≥1:40 to ≥2 of 3 antigens) at Day 28 post-vaccination. Vaccines were well tolerated with SC abatacept with background DMARDs. Conclusions In these sub-studies, patients with RA receiving SC abatacept and background DMARDs were able to mount an appropriate immune response to pneumococcal and influenza vaccines. Trial registration NCT00559585 (registered 15 November 2007) and NCT00663702 (registered 18 April 2008)