2,337 research outputs found

    Employee Preferences as a Factor in Pension Participation by Minority Workers

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    This project was designed to shed light on the widening gap between white and minority pension coverage during recent years. The hypothesis under investigation is that the divergence in white/minority coverage may be due in part to differences in the rates at which white and minority workers are choosing to participate in voluntary salary reduction plans. The availability of such plans has increased explosively in the past decade or so

    Atmospheric hydroxyl radical (OH) abundances from ground-based ultraviolet solar spectra: an improved retrieval method

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    The Fourier Transform Ultraviolet Spectrometer (FTUVS) instrument has recorded a long-term data record of the atmospheric column abundance of the hydroxyl radical (OH) using the technique of high resolution solar absorption spectroscopy. We report new efforts in improving the precision of the OH measurements in order to better model the diurnal, seasonal, and interannual variability of odd hydrogen (HOx) chemistry in the stratosphere, which, in turn, will improve our understanding of ozone chemistry and its long-term changes. Until the present, the retrieval method has used a single strong OH absorption line P1(1) in the near-ultraviolet at 32,341 cm−1. We describe a new method that uses an average based on spectral fits to multiple lines weighted by line strength and fitting precision. We have also made a number of improvements in the ability to fit a model to the spectral feature, which substantially reduces the scatter in the measurements of OH abundances

    Modulation of SIRT1-foxo1 signaling axis by resveratrol: Implications in skeletal muscle aging and insulin resistance

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    © 2015 S. Karger AG, Basel. Aging individuals and diabetic patients often exhibit concomitant reductions of skeletal muscle mass/strength and insulin sensitivity, suggesting an intimate link between muscle aging and insulin resistance. Foxo1, a member of the FOXO transcription factor family, is an important player in insulin signaling due to its inhibitory role in glucose uptake and utilization in skeletal muscle. Phosphorylation of Foxo1 is thought to mitigate the transactivation of pyruvate dehydrogenase lipoamide kinase 4 (PDK4), which is a negative regulator of the glycolytic enzyme pyruvate dehydrogenase (PDH). In contrast, how aging would regulate acetylation/deacetylation machineries and glucose utilization in skeletal muscle through the Foxo1/PDH axis remains largely undetermined. Accumulating body of evidence have shown that resveratrol, a natural polyphenol in grapes and red wine, activates the longevity-related protein sirtuin 1 (SIRT1) and augments insulin sensitivity in addition to its well-documented effects on mitochondrial energetics. The present review summarizes the role of Foxo1/SIRT1 in insulin signaling in skeletal muscle and proposes the insight that activation of SIRT1 deacetylase activity to deacetylate and suppress the Foxo1-induced transactivation of PDK4 may represent an anti-hyperglycemic mechanism of resveratrol in aging skeletal muscle.Link_to_subscribed_fulltex

    The influence of tropospheric biennial oscillation on mid-tropospheric CO_2

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    Mid-tropospheric CO_2 retrieved from the Atmospheric Infrared Sounder (AIRS) was used to investigate CO_2 interannual variability over the Indo-Pacific region. A signal with periodicity around two years was found for the AIRS mid-tropospheric CO_2 for the first time, which is related to the Tropospheric Biennial Oscillation (TBO) associated with the strength of the monsoon. During a strong (weak) monsoon year, the Western Walker Circulation is strong (weak), resulting in enhanced (diminished) CO_2 transport from the surface to the mid-troposphere. As a result, there are positive (negative) CO2 anomalies at mid-troposphere over the Indo-Pacific region. We simulated the influence of the TBO on the mid-tropospheric CO_2 over the Indo-Pacific region using the MOZART-2 model, and results were consistent with observations, although we found the TBO signal in the model CO_2 is to be smaller than that in the AIRS observations

    Radiation-Associated Angiosarcoma of the Breast: A Case Report and Literature Review.

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    In the last couple of decades, breast conservation therapy, which utilizes a combination of surgery, radiotherapy, and endocrine or chemotherapy, has become the standard of care for treating early-stage breast cancer. This practice has been greatly beneficial in the improvement of the patient's quality of life but has also led to the increased use of radiotherapy and associated soft-tissue sarcomas, with angiosarcoma being the most common malignancy. Radiation-associated angiosarcoma (RAS) of the breast is a rare phenomenon, which has been reported to occur in approximately 0.9 out of 1,000 cases, with a reported onset as late as 23 years following radiotherapy. Here we report 2 cases of RAS that occurred within 6 and 13 years following radiotherapy of their primary breast lesion. We discuss the diagnostic and therapeutic challenges regarding this disease and review the current literature. This case report serves as cautionary lessons on the importance of considering RAS of the breast in the differential diagnosis during evaluation for recurrent breast neoplasms. Ongoing clinical trials using combinations of vascular endothelial growth factor inhibitors and chemotherapy may provide future avenues of treatment for this difficult-to-treat disease

    Modulation of Midtropospheric CO_2 by the South Atlantic Walker Circulation

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    Midtropospheric CO_2 data from the Atmospheric Infrared Sounder (AIRS) are used in this study to explore the variability of CO_2 over the South Atlantic Ocean. It was found that the area-averaged CO_2 over the South Atlantic Ocean is less than that over South America by about 1 ppm during December–March. This CO_2 contrast is due to the large-scale vertical circulation over this region. During December–March, there is sinking motion over the South Atlantic Ocean. The sinking motion brings high-altitude air with a slightly lower concentration of CO_2 to the midtroposphere. Meanwhile, air rising over South America brings near-surface air with a higher concentration of CO_2 to the midtroposphere. As a result, the AIRS midtropospheric CO_2 concentration is lower over the South Atlantic Ocean than over South America during December–March. The detrended AIRS midtropospheric CO_2 difference correlates well with the inverted and detrended 400-hPa vertical pressure velocity difference between the South Atlantic and South America. Results obtained from this study demonstrate the strong impact of large-scale circulation on the vertical distribution of CO_2 in the free troposphere and suggest that midtropospheric CO_2 measurements can be used as an innovative observational constraint on the simulation of large-scale circulations in climate models

    Atomic level modeling of extremely thin silicon-on-insulator MOSFETs including the silicon dioxide: Electronic structure

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    © 1963-2012 IEEE. Ultimate scaling of Si MOSFETs leads to extremely thin and short channels, which are justifiably modeled at the atomic level. Currently, hydrogen passivation of the channel is used in device models, as a compromise between efficiency and accuracy. This paper advances the state of the art by adopting a density-functional tight-binding Hamiltonian, permitting the inclusion of the confining amorphous oxide explicitly in the simulation domain in a way similar to ab initio approaches. Band structure of silicon-on-insulator films of different thicknesses is studied with this method, showing good agreement with the experiment and revealing large quantitative differences in comparison with simulations of H-passivated Si film.published_or_final_versio

    Phylogenetic screening of a bacterial, metagenomic library using homing endonuclease restriction and marker insertion

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    Metagenomics provides access to the uncultured majority of the microbial world. The approaches employed in this field have, however, had limited success in linking functional genes to the taxonomic or phylogenetic origin of the organism they belong to. Here we present an efficient strategy to recover environmental DNA fragments that contain phylogenetic marker genes from metagenomic libraries. Our method involves the cleavage of 23S ribsosmal RNA (rRNA) genes within pooled library clones by the homing endonuclease I-CeuI followed by the insertion and selection of an antibiotic resistance cassette. This approach was applied to screen a library of 6500 fosmid clones derived from the microbial community associated with the sponge Cymbastela concentrica. Several fosmid clones were recovered after the screen and detailed phylogenetic and taxonomic assignment based on the rRNA gene showed that they belong to previously unknown organisms. In addition, compositional features of these fosmid clones were used to classify and taxonomically assign a dataset of environmental shotgun sequences. Our approach represents a valuable tool for the analysis of rapidly increasing, environmental DNA sequencing information

    Temperature-dependent photoluminescence of Ge/Si and Ge 1-ySn y/Si, indicating possible indirect-to-direct bandgap transition at lower Sn content

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    Temperature (T)-dependent photoluminescence (PL) has been investigated for both p-Ge and n-Ge1-ySny films grown on Si substrates. For the p-Ge, strong direct bandgap (ED) along with weak indirect bandgap related (EID) PL at low temperatures (LTs) and strong ED PL at room temperature (RT) were observed. In contrast, for the n-Ge1-ySny, very strong dominant EID PL at LT and strong ED PL were observed at RT. This T-dependent PL study indicates that the indirect-to-direct bandgap transitions of Ge1-ySny might take place at much lower Sn contents than the theory predicts, suggesting that these Ge1-ySny could become very promising direct bandgap semiconductors
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