5,414 research outputs found
Westward-propagating SST Anomalies and Baroclinic Eddies in the Sargasso Sea
Previous studies have documented the existence of a zonal band of strong, persistent, westward-propagating sea surface temperature (Ts) anomalies with zonal wavelengths of ≈800 km and periods of ≈200 days that are confined to the subtropical convergence zone (STCZ, roughly 26°–32°N). Two years of satellite-derived sea surface temperature (Ts) and sea surface elevation anomaly (η) maps of the Sargasso Sea (22.5°–33.5°N, 71.5°–59.5°W) are analyzed to determine how these anomalies are forced and why they an confined to the STCZ. A simple anomaly model forced by horizontal eddy currents and damped by a linear feedback mechanism explains many properties of the anomaly response. At wavelengths exceeding several hundred kilometers, forcing by horizontal eddy currents becomes less important relative to atmospheric forcing with increasing wavelength. The anomalies are confined to the STCZ partly because the large mean Ts gradient there enables the horizontal eddy currents to be relatively effective at forcing anomalies. Also, the eddies that force these anomalies, wavelike features with wavelengths of ∼800 km and periods of ∼200 days, are themselves confined to the STCZ. These wavelike eddies were not detecting during earlier experiments such as MODE because the domains within which they were conducted were too small. Within the STCZ, zonal dispersion properties of the eddy field are consistent with baroclinic Rossby wave variability. To the north and south of the STCZ, however, zonal dispersion properties differ substantially from the properties observed within the STCZ. The eddy dispersion properties change abruptly across transition zones 1–2 degree wide centered at 32.5° and 25.5°N. A simple linearized reduced-gravity model is used to demonstrate that interaction between eddies and zonal mean currents can qualitatively account for the change is dispersion properties south of the STCZ, but not to the north within the Gulf Stream recirculation region
Proximal and distal esophageal contractions in patients with vigorous or classic esophageal Chagas' disease
Identification and microbial production of a terpene-based advanced biofuel
Rising petroleum costs, trade imbalances and environmental concerns have stimulated efforts to advance the microbial production of fuels from lignocellulosic biomass. Here we identify a novel biosynthetic alternative to D2 diesel fuel, bisabolane, and engineer microbial platforms for the production of its immediate precursor, bisabolene. First, we identify bisabolane as an alternative to D2 diesel by measuring the fuel properties of chemically hydrogenated commercial bisabolene. Then, via a combination of enzyme screening and metabolic engineering, we obtain a more than tenfold increase in bisabolene titers in Escherichia coli to >900 mg l−1. We produce bisabolene in Saccharomyces cerevisiae (>900 mg l−1), a widely used platform for the production of ethanol. Finally, we chemically hydrogenate biosynthetic bisabolene into bisabolane. This work presents a framework for the identification of novel terpene-based advanced biofuels and the rapid engineering of microbial farnesyl diphosphate-overproducing platforms for the production of biofuels
Multidimensional sexual perfectionism and female sexual function: A longitudinal investigation
Research on multidimensional sexual perfectionism differentiates four forms of sexual perfectionism: self-oriented, partner-oriented, partner-prescribed, and socially prescribed. Self-oriented sexual perfectionism reflects perfectionistic standards people apply to themselves as sexual partners; partner-oriented sexual perfectionism reflects perfectionistic standards people apply to their sexual partner; partner-prescribed sexual perfectionism reflects people’s beliefs that their sexual partner imposes perfectionistic standards on them; and socially prescribed sexual perfectionism reflects people’s beliefs that society imposes such standards on them. Previous studies found partner-prescribed and socially prescribed sexual perfectionism to be maladaptive forms of sexual perfectionism associated with a negative sexual self-concept and problematic sexual behaviors, but only examined cross-sectional relationships. The present article presents the first longitudinal study examining whether multidimensional sexual perfectionism predicts changes in sexual self-concept and sexual function over time. A total of 366 women aged 17-69 years completed measures of multidimensional sexual perfectionism, sexual esteem, sexual anxiety, sexual problem self-blame, and female sexual function (cross-sectional data). Three to six months later, 164 of the women completed the same measures again (longitudinal data). Across analyses, partner-prescribed sexual perfectionism emerged as the most maladaptive form of sexual perfectionism. In the cross-sectional data, partner-prescribed sexual perfectionism showed positive relationships with sexual anxiety, sexual problem self-blame, and intercourse pain and negative relationships with sexual esteem, desire, arousal, lubrication, and orgasmic function. In the longitudinal data, partner-prescribed sexual perfectionism predicted increases in sexual anxiety and decreases in sexual esteem, arousal, and lubrication over time. The findings suggest that partner-prescribed sexual perfectionism contributes to women’s negative sexual self-concept and female sexual dysfunction
Internal Monitoring of Acoustic Emission in Graphite-Epoxy Composites Using Imbedded Optical Fiber Sensors
The monitoring of acoustic emission (AE) is an important technique for the nondestructive characterization of strained materials because time and frequency domain analyses of AE events yield information about the type, geometry, and location of defects, as well as how material failure may occur. The quantitative interpretation of AE event signatures is critically dependent upon the faithfulness of the acoustic transduction and signal processing system in reproducing localized stress wave amplitude as a function of time. Although the usual sensor for acoustic emission is the piezoelectric transducer, several investigators have considered the application of interferometric optical sensing techniques which offer good spatial resolution and frequency response [1,2]. These techniques typically focus one beam of a modified Michelson interferometer to a small spot on the surface of a specimen and measure the time-dependent normal component of surface displacement at the location of that spot
Unveiling the nature of the "Green Pea" galaxies
We review recent results on the oxygen and nitrogen chemical abundances in
extremely compact, low-mass starburst galaxies at redshifts between 0.1-0.3
recently named to as "Green Pea" galaxies. These galaxies are genuine
metal-poor galaxies ( one fifth solar) with N/O ratios unusually high for
galaxies of the same metallicity. In combination with their known general
properties, i.e., size, stellar mass and star-formation rate, these findings
suggest that these objects could be experiencing a short and extreme phase in
their evolution. The possible action of both recent and massive inflow of gas,
as well as stellar feedback mechanisms are discussed here as main drivers of
the starburst activity and their oxygen and nitrogen abundances.Comment: To appear in JENAM Symposium "Dwarf Galaxies: Keys to Galaxy
Formation and Evolution", P. Papaderos, G. Hensler, S. Recchi (eds.). Lisbon,
September 2010, Springer Verlag, in pres
Clinical and histologic features of botryoid odontogenic cyst: a case report
<p>Abstract</p> <p>Introduction</p> <p>The lateral periodontal cyst, as the name implies, occurs on a lateral periodontal location and is of developmental origin, arising from cystic degeneration of clear cells of the dental lamina. A botryoid odontogenic cyst is considered to be a rare multilocular variant of a lateral periodontal cyst.</p> <p>Case presentation</p> <p>We report the clinical and histopathologic features of a rare case of botryoid odontogenic cyst found in an edentulous area corresponding to the right lower canine of a 64-year-old African-American woman. A multilocular radiolucency was observed, and surgical removal of the lesion revealed a nodule of rubber-like consistency measuring about 1.5 cm in diameter. Cross-sectioning of the nodule showed that it consisted of various cystic compartments. Histologically, various voluminous periodic acid-Schiff-negative clear cells randomly distributed throughout the cystic epithelium were observed, as well as cell layers showing thickenings generally formed by oval, sometimes entangled plaques. The capsule consisted of fibrous connective tissue and showed rare and discrete foci of a perivascular mononuclear inflammatory infiltrate and reactive bone-tissue fragments. The final diagnosis was botryoid odontogenic cyst.</p> <p>Conclusion</p> <p>We provide data that allow the reader to establish the differences between botryoid odontogenic cyst, glandular odontogenic cyst, and lateral periodontal cyst, helping with the differential diagnosis. The reader will have the opportunity to review botryoid odontogenic cyst clinical and histopathologic features, including treatment.</p
Successful Medical Management of Status Post-Roux-en-Y-Gastric-Bypass Hyperinsulinemic Hypoglycemia
Roux-en-Y gastric bypass (RYGBP) is the most commonly performed type of bariatric surgery, which is used in the treatment of obesity and type 2 diabetes. Recent case reports and case series have described a rare complication of RYGBP, status post-gastric-bypass hyperinsulinemic hypoglycemia, which was mainly managed successfully with pancreatectomy. In this letter, we describe the first successful management of status post-gastric-bypass hyperinsulinemic hypoglycemia with diazoxide
- …