Galactic S Stars: Investigations of Color, Motion, and Spectral Features

Known bright S stars, recognized as such by their enhanced s-process abundances and C/O ratio, are typically members of the asymptotic giant branch (AGB) or the red giant branch (RGB). Few modern digital spectra for these objects have been published, from which intermediate resolution spectral indices and classifications could be derived. For published S stars we find accurate positions using the Two-Micron All Sky Survey (2MASS), and use the FAST spectrograph of the Tillinghast reflector on Mt. Hopkins to obtain the spectra of 57 objects. We make available a digital S star spectral atlas consisting of 14 spectra of S stars with diverse spectral features. We define and derive basic spectral indices that can help distinguish S stars from late-type (M) giants and carbon stars. We convolve all our spectra with the SDSS bandpasses, and employ the resulting gri magnitudes together with 2MASS JHK mags to investigate S star colors. S stars have colors similar to carbon and M stars, and are therefore difficult to distinguish by color alone. Using near and mid-infrared colors from IRAS and AKARI, we identify some of the stars as intrinsic (AGB) or extrinsic (with abundances enhanced by past mass-transfer). We also use V band and 2MASS magnitudes to calculate a temperature index for stars in the sample. We analyze the proper motions and parallaxes of our sample stars to determine upper and lower limit absolute magnitudes and distances, and confirm that most are probably giants.Comment: 11 pages. Accepted for publication in ApJS July 19, 2011. Spectra available as http://hea-www.harvard.edu/~pgreen/SStarAtlas.ta

Carbon enrichment of the evolved stars in the Sagittarius dwarf spheroidal

We present spectra of 1142 colour-selected stars in the direction of the Sagittarius Dwarf Spheroidal (Sgr dSph) galaxy, of which 1058 were taken with VLT/FLAMES multi-object spectrograph and 84 were taken with the SAAO Radcliffe 1.9-m telescope grating spectrograph. Spectroscopic membership is confirmed (at >99% confidence) for 592 stars on the basis of their radial velocity, and spectral types are given. Very slow rotation is marginally detected around the galaxy's major axis. We identify five S stars and 23 carbon stars, of which all but four carbon stars are newly-determined and all but one (PQ Sgr) are likely Sgr dSph members. We examine the onset of carbon-richness in this metal-poor galaxy in the context of stellar models. We compare the stellar death rate (one star per 1000-1700 years) to known planetary nebula dynamical ages and find that the bulk population produce the observed (carbon-rich) planetary nebulae. We compute average lifetimes of S and carbon stars as 60-250 and 130-500 kyr, compared to a total thermal-pulsing asymptotic giant branch lifetime of 530-1330 kyr. We conclude by discussing the return of carbon-rich material to the ISM.Comment: 14 pages, 10 figures, accepted MNRA

High density lipoproteins mediate in vivo protection against staphylococcal phenol-soluble modulins

Staphylococcus aureus virulence has been associated with the production of phenol-soluble modulins (PSMs). These PSMs have distinct virulence functions and are known to activate, attract and lyse neutrophils. These PSM-associated biological functions are inhibited by lipoproteins in vitro. We set out to address whether lipoproteins neutralize staphylococcal PSM-associated virulence in experimental animal models. Serum from both LCAT an ABCA1 knockout mice strains which are characterised by near absence of high-density lipoprotein (HDL) levels, was shown to fail to protect against PSM-induced neutrophil activation and lysis in vitro. Importantly, PSM-induced peritonitis in LCAT-/- mice resulted in increased lysis of resident peritoneal macrophages and enhanced neutrophil recruitment into the peritoneal cavity. Notably, LCAT-/- mice were more likely to succumb to staphylococcal bloodstream infections in a PSM-dependent manner. Plasma from homozygous carriers of ABCA1 variants characterized by very low HDL-cholesterol levels, was found to be less protective against PSM-mediated biological functions compared to healthy humans. Therefore, we conclude that lipoproteins present in blood can protect against staphylococcal PSMs, the key virulence factor of community-associated methicillin resistant S. aureus.Biopharmaceutic

Population structure and linkage disequilibrium unravelled in tetraploid potato

Association mapping is considered to be an important alternative strategy for the identification of quantitative trait loci (QTL) as compared to traditional QTL mapping. A necessary prerequisite for association analysis to succeed is detailed information regarding hidden population structure and the extent of linkage disequilibrium. A collection of 430 tetraploid potato cultivars, comprising two association panels, has been analysed with 41 AFLP® and 53 SSR primer combinations yielding 3364 AFLP fragments and 653 microsatellite alleles, respectively. Polymorphism information content values and detected number of alleles for the SSRs studied illustrate that commercial potato germplasm seems to be equally diverse as Latin American landrace material. Genome-wide linkage disequilibrium (LD)—reported for the first time for tetraploid potato—was observed up to approximately 5 cM using r2 higher than 0.1 as a criterion for significant LD. Within-group LD, however, stretched on average twice as far when compared to overall LD. A Bayesian approach, a distance-based hierarchical clustering approach as well as principal coordinate analysis were adopted to enquire into population structure. Groups differing in year of market release and market segment (starch, processing industry and fresh consumption) were repeatedly detected. The observation of LD up to 5 cM is promising because the required marker density is not likely to disable the possibilities for association mapping research in tetraploid potato. Population structure appeared to be weak, but strong enough to demand careful modelling of genetic relationships in subsequent marker-trait association analyses. There seems to be a good chance that linkage-based marker-trait associations can be identified at moderate marker densities

Esophageal cancer: CT, endoscopie US, and FDG PET for assessment of response to neoadjuvant therapy-systematic review

PURPOSE: To compare diagnostic accuracy of computed tomography (CT), endoscopic ultrasonography (US), and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) for assessment of response to neoadjuvant therapy in patients with esophageal cancer by using a systematic review of the literature. MATERIALS AND METHODS: MEDLINE and EMBASE databases and Cochrane Database of Systematic Reviews were searched for relevant studies. Two reviewers independently assessed the methodological quality of each study. Summary receiver operating characteristic (ROC) analysis was used to summarize and compare the diagnostic accuracy of the three modalities. RESULTS: Four studies with CT, 13 with endoscopic US, and seven with FDC PET met inclusion criteria. Percentages of the maximum score in regard to methodological quality ranged from 15% to 100%. Summary ROC analysis could be performed for three studies with CT, four with endoscopic US, and four with FDG PET. The maximum joint values for sensitivity and specificity were 54% for CT, 86% for endoscopic US, and 85% for FDG PET. Accuracy of CT was significantly lower than that of FDG PET (P < .006) and of endoscopic US (P < .003). Accuracy of FDG PET and that of endoscopic US were similar (P = .839). In all patients, CT was always feasible, whereas endoscopic US was not feasible in 6% of the patients, and FDG PET was not feasible in less than 1%. CONCLUSION: CT has poor accuracy for assessment of response to neoadjuvant therapy in patients with esophageal cancer. Endoscopic US and FDG PET have equivalent good accuracy, but endoscopic US is not always feasible after chemotherapy and radiation therapy. FDG PET seems to be a promising noninvasive tool for assessment of neoadjuvant therapy in patients with esophageal cancer

Chronic pulmonary embolism in Klippel-Trenaunay syndrome

Background: Klippel-Trenaunay syndrome (KTS) is characterized by vascular malformations and disturbed soft tissue or bony growth, involving one or more extremities. A high incidence of venous thromboembolism (VTE) has been reported in this disorder, along with cases of belated diagnosed chronic thromboembolic (CTE) pulmonary hypertension (CTEPH). We performed a cross-sectional study to investigate the prevalence of GTE in patients with KTS. Methods: Those from our KTS patient cohort willing to participate were examined with a sequential diagnostic workup including perfusion scintigraphy, computed tomography, and echocardiography. Results: Of 68 patients, 48 patients participated in the study (median age 43 years; 29 [60%] were female). Eleven patients (23%) had an abnormal perfusion scan result, of whom computed tomographic scanning showed signs of GTE in two patients (4.2%; 95% confidence interval [CI] 1.2%-14%); both patients had a history of VTE. Echocardiography showed no signs of CTEPH in these patients. In total, 23 patients (48%; 95% CI 35%-62%) had a history of superficial vein thrombosis and 8 patients (17%; 95% CI 8.7%-30%) had a history of deep Vein thrombosis or pulmonary embolism, which was associated with more shortness of breath. Limitations: Echocardiography was only performed in patients with GTE. Conclusion: A large proportion of patients with KTS had a history of VTE. The prevalence of GTE in the total KTS cohort, however, appeared less alarming than previously assumed. Based on these results, we suggest that there is only a limited indication for CTEPH screening among patients with KTS. Nevertheless, awareness for CTEPH remains appropriate, especially among patients presenting with shortness of breath and a history of VTE. (J Am Acad Dermatol 2012;66:71-7.

On the conversion of functional models: Bridging differences between functional taxonomies in the modeling of user actions

In this paper, I discuss a methodology for the conversion of functional models between functional taxonomies developed by Kitamura et al. (2007) and Ookubo et al. (2007). They apply their methodology to the conversion of functional models described in terms of the Functional Basis taxonomy into functional models described in terms of the Functional Concept Ontology taxonomy. I argue that this model conversion harbors two problems. One, a step in this model conversion that is aimed to handle differences in the modeling of user features consists of the removal of Functional Basis functions. It is shown that this removal can lead to considerable information loss. Two, some Functional Basis functions that I argue correspond to user functions, get re-interpreted as device functions in the model conversion. I present an alternative strategy that prevents information loss and information change in model conversions between the Functional Basis and Functional Concept Ontology taxonomies.Values and TechnologyTechnology, Policy and Managemen