Design and Analysis of Novel Ge-GeTe PN Junction for Photovoltaics

The continuing rise in demand for energy places a similarly increasing demand to improve power production methods and efficiency. In regards to solar power generation, one major limiting factor with existing photovoltaic (PV) systems is the management of heat produced and photon interactions with the PV device. Typical devices operate within the 300-1000 nm range of the solar spectrum, greatly limiting the range of photons used for power generation. Furthermore, since infrared light

Trade, Balance of Payments and Growth

Reviews the book Trade, Balance of Payments and Growth, edited by J. Bhagwati, R.W. Jones, R.A. Mundell and J. Vanek

Balmer filaments in Tycho's supernova remnant: an interplay between cosmic-ray and broad-neutral precursors

We present H$\alpha$ spectroscopic observations and detailed modelling of the Balmer filaments in the supernova remnant Tycho. We used Galaxy H$\alpha$ Fabry-P\'erot Spectrometer on the William Herschel Telescope with a 3.4'$\times$3.4' field-of-view, 0.2" pixel scale and \sigma_\rm{instr}=8.1 km/s resolution at 1" seeing for $\sim10$ hours, resulting in 82 spatial-spectral bins that resolve the narrow H$\alpha$ line in the entire Tycho's northeastern rim. For the first time, we can mitigate artificial line broadening from unresolved differential motion, and probe H$\alpha$ emission parameters in varying shock and ambient medium conditions. Broad H$\alpha$ line remains unresolved within spectral coverage of 392 km/s. We employed Bayesian inference to obtain reliable parameter confidence intervals, and quantify the evidence for models with multiple line components. The median H$\alpha$ narrow-line full-width at half-maximum of all bins and models is W_\rm{NL}=(54.8\pm1.8) km/s at the $95\%$ confidence level, varying within [35, 72] km/s between bins and clearly broadened compared to the intrinsic (thermal) $\approx20$ km/s. Possible line splits are accounted for, significant in $\approx18\%$ of the filament, and presumably due to remaining projection effects. We also find wide-spread evidence for intermediate-line emission of a broad-neutral precursor, with median W_\rm{IL}=(180\pm14) km/s ($95\%$ confidence). Finally, we present a measurement of the remnant's systemic velocity, V_\rm{LSR}=-34 km/s, and map differential line-of-sight motions. Our results confirm the existence and interplay of shock precursors in Tycho's remnant. In particular, we show that suprathermal narrow-line emission is near-universal in Tycho and that, in absence of an alternative explanation, collisionless supernova remnant shocks constitute a viable acceleration source for Galactic TeV Cosmic-Ray protons.Comment: 36 pages, 17 figures, 5 tables, Paper accepted for publication in the Astrophysical Journal; References correcte

Association of Systemic Inflammation With Retinal Vascular Caliber in Patients With AIDS.

PurposeTo evaluate relationships among retinal vascular caliber and biomarkers of systemic inflammation in patients with AIDS.MethodsA total of 454 participants with AIDS had retinal vascular caliber (central retinal artery equivalent and central retinal vein equivalent) determined from enrollment retinal photographs by reading center graders masked to clinical and biomarker information. Cryopreserved plasma specimens were assayed for inflammatory biomarkers, including C-reactive protein (CRP), IL-6, interferon-γ inducible protein (IP)-10, kynurenine/tryptophan (KT) ratio, and intestinal fatty acid binding protein (I-FABP).ResultsIn the simple linear regression of retinal vascular caliber on plasma biomarkers, elevated CRP, IL-6, and IP-10 were associated with retinal venular dilation, and elevated KT ratio with retinal arteriolar narrowing. In the multiple linear regression, including baseline characteristics and plasma biomarkers, AMD was associated with dilation of retinal arterioles (mean difference: 9.1 μm; 95% confidence interval [CI] 5.2, 12.9; P < 0.001) and venules (mean difference, 10.9 μm; 95% CI, 5.3, 16.6; P < 0.001), as was black race (P < 0.001). Hyperlipidemia was associated with retinal venular narrowing (mean difference, -7.5 μm; 95% CI, -13.7, -1.2; P = 0.02); cardiovascular disease with arteriolar narrowing (mean difference, -5.2 μm; 95% CI, -10.3, -0.1; P = 0.05); age with arteriolar narrowing (slope, -0.26 μm/year; 95% CI, -0.46, -0.06; P = 0.009); and IL-6 with venular dilation (slope, 5.3 μm/standard deviation log10[plasma IL-6 concentration]; 95% CI, 2.7, 8.0; P < 0.001).ConclusionsThese data suggest that retinal vascular caliber is associated with age, race, AMD, hyperlipidemia, cardiovascular disease, and selected biomarkers of systemic inflammation

Balmer-dominated shocks in Tycho's SNR: omnipresence of CRs

We present wide-field, spatially and highly resolved spectroscopic observations of Balmer filaments in the northeastern rim of Tycho's supernova remnant in order to investigate the signal of cosmic-ray (CR) acceleration. The spectra of Balmer-dominated shocks (BDSs) have characteristic narrow (FWHM $\sim$ 10 kms$^{-1}$) and broad (FWHM $\sim$ 1000 kms$^{-1}$) H$\alpha$ components. CRs affect the H$\alpha$-line parameters: heating the cold neutrals in the interstellar medium results in broadening of the narrow H$\alpha$-line width beyond 20 kms$^{-1}$, but also in reduction of the broad H$\alpha$-line width due to energy being removed from the protons in the post-shock region. For the first time we show that the width of the narrow H$\alpha$ line, much larger than 20 kms$^{-1}$, is not a resolution or geometric effect nor a spurious result of a neglected intermediate (FWHM $\sim$ 100 kms$^{-1}$) component resulting from hydrogen atoms undergoing charge exchange with warm protons in the broad-neutral precursor. Moreover, we show that a narrow line width $\gg$ 20 kms$^{-1}$ extends across the entire NE rim, implying CR acceleration is ubiquitous, and making it possible to relate its strength to locally varying shock conditions. Finally, we find several locations along the rim, where spectra are significantly better explained (based on Bayesian evidence) by inclusion of the intermediate component, with a width of 180 kms$^{-1}$ on average.Comment: Proceeding for contributed talk at the IAU Symposium No. 331: "SN 1987A, 30 years later - Cosmic Rays and Nuclei from Supernovae and their Aftermaths", 2017, La Reunion Island; References correcte

On the Origin of X-ray Emission From Millisecond Pulsars in 47 Tuc

The observed spectra and X-ray luminosities of millisecond pulsars in 47 Tuc can be interpreted in the context of theoretical models based on strong, small scale multipole fields on the neutron star surface. For multipole fields that are relatively strong as compared to the large scale dipole field, the emitted X-rays are thermal and likely result from polar cap heating associated with the return current from the polar gap. On the other hand, for weak multipole fields, the emission is nonthermal and results from synchrotron radiation of $e^{\pm}$ pairs created by curvature radiation. The X-ray luminosity, $L_x$, is related to the spin down power, $L_{sd}$, expressed in the form $L_x \propto L^{\beta}_{sd}$ with $\beta \sim 0.5$ and $\sim 1$ for strong and weak multipole fields respectively. If the polar cap size is of the order of the length scale of the multipole field, $s$ and $\beta \sim 0.5$, the polar cap temperature is $\sim 3 \times 10^6 K (\frac{L_{sd}}{10^{34}erg s^{-1}})^{1/8} (\frac{s}{3\times 10^4 cm})^{-1/2}$. A comparison of the X-ray properties of millisecond pulsars in globular clusters and in the Galactic field suggests that the emergence of relatively strong small scale multipole fields from the neutron star interior may be correlated with the age and evolutionary history of the underlying neutron star.Comment: 25 pages, 2 figures, accepted for publication in Ap

Transport processes of particles in dilute suspensions in turbulent water flow–phase I

Modifications to an existing experimental system have been made and have been demonstrated to provide the required resolution and variable parameterization necessary for a detailed study of dilute particle suspensions in a turbulent water flow. These modifications together with the reasons for their necessity are discussed. Linearization of non-Stokesian drag has been accomplished through the introduction of a diagonal tensor into the Stokes drag force equation. It was found that non-Stokesian effects tend to be of minor importance in the response of water borne particles.U.S. Department of the InteriorU.S. Geological SurveyOpe

Randomized trial of inhaled nitric oxide to treat acute pulmonary embolism: The iNOPE trial

BACKGROUND: The study hypothesis is that administration of inhaled nitric oxide (NO) plus oxygen to subjects with submassive pulmonary embolism (PE) will improve right ventricular (RV) systolic function and reduce RV strain and necrosis, while improving patient dyspnea, more than treatment with oxygen alone. METHODS: This article describes the rationale and protocol for a registered (NCT01939301), nearly completed phase II, 3-center, randomized, double-blind, controlled trial. Eligible patients have pulmonary imaging-proven acute PE. Subjects must be normotensive, and have RV dysfunction on echocardiography or elevated troponin or brain natriuretic peptide and no fibrinolytics. Subjects receive NO plus oxygen or placebo for 24 hours (±3 hours) with blood sampling before and after treatment, and mandatory echocardiography and high-sensitivity troponin posttreatment to assess the composite primary end point. The sample size of N=78 was predicated on 30% more NO-treated patients having a normal high-sensitivity troponin (<14 pg/mL) and a normal RV on echocardiography at 24 hours with α=.05 and β=.20. Safety was ensured by continuous spectrophotometric monitoring of percentage of methemoglobinemia and a predefined protocol to respond to emergent changes in condition. Blinding was ensured by identical tanks, software, and physical shielding of the device display and query of the clinical care team to assess blinding efficacy. RESULTS: We have enrolled 78 patients over a 31-month period. No patient has been withdrawn as a result of a safety concern, and no patient has had a serious adverse event related to NO. CONCLUSIONS: We present methods and a protocol for the first double-blinded, randomized trial of inhaled NO to treat PE

Antimicrobial susceptibility of bacteria isolated from the lower respiratory tract of inpatients with pneumonia in Brazilian hospitals: results from the SENTRY surveillance program, 1997 and 1998

Background: Nosocomial pneumonia is the most common fatal nosocomial infection with attributable mortality rates ranging from 30 to 60% and a rapid initiation of optimal antimicrobial therapy is important to obtain treatment success. SENTRY is a comprehensive antimicrobial surveillance study involving a great number of medical centers distributed worldwide. Objective: To evaluate the antimicrobial susceptibility of bacterial isolates collected from the lower respiratory tract of inpatients with pneumonia. Material & methods: The authors report the antimicrobial susceptibility of 525 isolates collected in 11 Brazilian hospitals, as part of the SENTRY program. The isolates were tested for susceptibility by broth micro-dilution against a large number of drugs. Results: The five most frequently isolated species were (n/%): Pseudomonas aeruginosa (158/30.1%), Staphylococcus aureus (103/19.6%), Acinetobacter spp. (68/13.0%), Klebsiella spp. (50/9.5%), and Enterobacter spp. (44/8.4%). These five species represented more than 80% of all isolates. P. aeruginosa demonstrated high rates of resistance to most antimicrobial agents tested. The highest susceptibility rates were shown by piperacillin/tazobactam (71.5%) and meropenem (69.0%). Acinetobacter spp. also showed very high rates of resistance. The most active compounds against this species were imipenem and meropenem (80.9% susceptibility) followed by tetracycline (63.2% susceptibility). Cephalosporin susceptibilities among Klebsiella spp were very low and 36.0% of isolates were considered ESBL producers based on increased MICs, > 2 mug/mL) to ceftriaxone or ceftazidime or aztreonam. Ceftriaxone was active against only 56.8% of Enterobacter spp. isolates (MIC50 1 mug/mL), while cefepime was active against 88.6% of these isolates (MIC, ou =2mig/mL para ceftriaxona ou ceftazidima, indicando produção de ESBL, foram encontrados em 36,0% das amostras. Os antimicrobianos mais ativos contra Klebsiella spp. foram os carbapenens (100% de sensibilidade) e as quinolonas (92,0% de sensibilidade). Ceftriaxona foi ativa contra somente 56,8% das amostras de Enterobacter spp. (MIC50, 1mig/mL), enquanto a cefepima foi ativa contra 88,6% destes isolados (MIC50, <= 0,12mig/mL). A resistência à oxacilina foi detectada em 43,7% dos isolados de S. aureus. As drogas mais ativas contra essa espécie foram: vancomicina, teicoplanina, quinupristin-dalfopristin e linezolida. Conclusões: Os resultados do presente estudo mostraram alta prevalência de Acinetobacter spp. e altas taxas de resistência entre bacilos gram-negativos quando comparados com resultados de estudos norte-americanos e europeus.Universidade Federal de São Paulo (UNIFESP)Universidade de Iowa Faculdade de Medicina Departmento de PatologiaLaboratório Santa LuziaLaboratório LâminaUNIFESPSciEL

The SEGUE Stellar Parameter Pipeline. II. Validation with Galactic Globular and Open Clusters

We validate the performance and accuracy of the current SEGUE (Sloan Extension for Galactic Understanding and Exploration) Stellar Parameter Pipeline (SSPP), which determines stellar atmospheric parameters (effective temperature, surface gravity, and metallicity) by comparing derived overall metallicities and radial velocities from selected likely members of three globular clusters (M 13, M 15, and M 2) and two open clusters (NGC 2420 and M 67) to the literature values. Spectroscopic and photometric data obtained during the course of the original Sloan Digital Sky Survey (SDSS-I) and its first extension (SDSS-II/SEGUE) are used to determine stellar radial velocities and atmospheric parameter estimates for stars in these clusters. Based on the scatter in the metallicities derived for the members of each cluster, we quantify the typical uncertainty of the SSPP values, sigma([Fe/H]) = 0.13 dex for stars in the range of 4500 K < Teff < 7500 K and 2.0 < log g < 5.0, at least over the metallicity interval spanned by the clusters studied (-2.3 < [Fe/H] < 0). The surface gravities and effective temperatures derived by the SSPP are also compared with those estimated from the comparison of the color-magnitude diagrams with stellar evolution models; we find satisfactory agreement. At present, the SSPP underestimates [Fe/H] for near-solar-metallicity stars, represented by members of M 67 in this study, by about 0.3 dex.Comment: 56 pages, 8 Tables, 15 figures, submitted to the Astronomical Journa