Chemical trends in the Galactic halo from APOGEE data

Indexación: Web of Science; Scopus.The galaxy formation process in the A cold dark matter scenario can be constrained from the analysis of stars in the Milky Way's halo system. We examine the variation of chemical abundances in distant halo stars observed by the Apache Point Observatory Galactic Evolution Experiment ( APOGEE), as a function of distance from the Galactic Centre ( r) and iron abundance ([M/H]), in the range 5 less than or similar to r less than or similar to 30 kpc and - 2.5 15 kpc and [M/H] > - 1.1 (larger in the case of O, Mg, and S) with respect to the nearest halo stars. This result confirms previous claims for low-alpha stars found at larger distances. Chemical differences in elements with other nucleosynthetic origins (Ni, K, Na, and Al) are also detected. C and N do not provide reliable information about the interstellar medium from which stars formed because our sample comprises red giant branch and asymptotic giant branch stars and can experience mixing of material to their surfaces.https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/stw286

IMF and [Na/Fe] abundance ratios from optical and NIR Spectral Features in Early-type Galaxies

We present a joint analysis of the four most prominent sodium-sensitive features (NaD, NaI8190, NaI1.14, and NaI2.21), in the optical and Near-Infrared spectral range, of two nearby, massive (sigma~300km/s), early-type galaxies (named XSG1 and XSG2). Our analysis relies on deep VLT/X-Shooter long-slit spectra, along with newly developed stellar population models, allowing for [Na/Fe] variations, up to 1.2dex, over a wide range of age, total metallicity, and IMF slope. The new models show that the response of the Na-dependent spectral indices to [Na/Fe] is stronger when the IMF is bottom heavier. For the first time, we are able to match all four Na features in the central regions of massive early-type galaxies, finding an overabundance of [Na/Fe], in the range 0.5-0.7dex, and a bottom-heavy IMF. Therefore, individual abundance variations cannot be fully responsible for the trends of gravity-sensitive indices, strengthening the case towards a non-universal IMF. Given current limitations of theoretical atmosphere models, our [Na/Fe] estimates should be taken as upper limits. For XSG1, where line strengths are measured out to 0.8Re, the radial trend of [Na/Fe] is similar to [Mg/Fe] and [C/Fe], being constant out to 0.5Re, and decreasing by 0.2-0.3dex at 0.8Re, without any clear correlation with local metallicity. Such a result seems to be in contrast with the predicted increase of Na nucleosynthetic yields from AGB stars and TypeII SNe. For XSG1, the Na-inferred IMF radial profile is consistent, within the errors, with that derived from TiO features and the Wing-Ford band, presented in a recent paper

Efficacy and safety of ablation for people with non-paroxysmal atrial fibrillation.

: The optimal rhythm management strategy for people with non-paroxysmal (persistent or long-standing persistent) atrial fibrilation is currently not well defined. Antiarrhythmic drugs have been the mainstay of therapy. But recently, in people who have not responded to antiarrhythmic drugs, the use of ablation (catheter and surgical) has emerged as an alternative to maintain sinus rhythm to avoid long-term atrial fibrillation complications. However, evidence from randomised trials about the efficacy and safety of ablation in non-paroxysmal atrial fibrillation is limited. : To determine the efficacy and safety of ablation (catheter and surgical) in people with non-paroxysmal (persistent or long-standing persistent) atrial fibrillation compared to antiarrhythmic drugs. : We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid, Embase Ovid, conference abstracts, clinical trial registries, and Health Technology Assessment Database. We searched these databases from their inception to 1 April 2016. We used no language restrictions. : We included randomised trials evaluating the effect of radiofrequency catheter ablation (RFCA) or surgical ablation compared with antiarrhythmic drugs in adults with non-paroxysmal atrial fibrillation, regardless of any concomitant underlying heart disease, with at least 12 months of follow-up. : Two review authors independently selected studies and extracted data. We evaluated risk of bias using the Cochrane 'Risk of bias' tool. We calculated risk ratios (RRs) for dichotomous data with 95% confidence intervals (CIs) a using fixed-effect model when heterogeneity was low (I² &lt;= 40%) and a random-effects model when heterogeneity was moderate or substantial (I² &gt; 40%). Using the GRADE approach, we evaluated the quality of the evidence and used the GRADE profiler (GRADEpro) to import data from Review Manager 5 to create 'Summary of findings' tables. : We included three randomised trials with 261 participants (mean age: 60 years) comparing RFCA (159 participants) to antiarrhythmic drugs (102) for non-paroxysmal atrial fibrillation. We generally assessed the included studies as having low or unclear risk of bias across multiple domains, with reported outcomes generally lacking precision due to low event rates. Evidence showed that RFCA was superior to antiarrhythmic drugs in achieving freedom from atrial arrhythmias (RR 1.84, 95% CI 1.17 to 2.88; 3 studies, 261 participants; low-quality evidence), reducing the need for cardioversion (RR 0.62, 95% CI 0.47 to 0.82; 3 studies, 261 participants; moderate-quality evidence), and reducing cardiac-related hospitalisation (RR 0.27, 95% CI 0.10 to 0.72; 2 studies, 216 participants; low-quality evidence) at 12 months follow-up. There was substantial uncertainty surrounding the effect of RFCA regarding significant bradycardia (or need for a pacemaker) (RR 0.20, 95% CI 0.02 to 1.63; 3 studies, 261 participants; low-quality evidence), periprocedural complications, and other safety outcomes (RR 0.94, 95% CI 0.16 to 5.68; 3 studies, 261 participants; very low-quality evidence). : In people with non-paroxysmal atrial fibrillation, evidence suggests a superiority of RFCA to antiarrhythmic drugs in achieving freedom from atrial arrhythmias, reducing the need for cardioversion, and reducing cardiac-related hospitalisations. There was uncertainty surrounding the effect of RFCA with significant bradycardia (or need for a pacemaker), periprocedural complications, and other safety outcomes. Evidence should be interpreted with caution, as event rates were low and quality of evidence ranged from moderate to very low.<br/

REDSHIFT MEASUREMENT and SPECTRAL CLASSIFICATION for eBOSS GALAXIES with the REDMONSTER SOFTWARE

We describe the redmonster automated redshift measurement and spectral classification software designed for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV). We describe the algorithms, the template standard and requirements, and the newly developed galaxy templates to be used on eBOSS spectra. We present results from testing on early data from eBOSS, where we have found a 90.5% automated redshift and spectral classification success rate for the luminous red galaxy sample (redshifts 0.6 ≲ z ≲ 1.0). The redmonster performance meets the eBOSS cosmology requirements for redshift classification and catastrophic failures and represents a significant improvement over the previous pipeline. We describe the empirical processes used to determine the optimum number of additive polynomial terms in our models and an acceptable δX2rthreshold for declaring statistical confidence. Statistical errors on redshift measurement due to photon shot noise are assessed, and we find typical values of a few tens of km s-1. An investigation of redshift differences in repeat observations scaled by error estimates yields a distribution with a Gaussian mean and standard deviation of μ ∼ 0.01 and σ ∼ 0.65, respectively, suggesting the reported statistical redshift uncertainties are over-estimated by ∼54%. We assess the effects of object magnitude, signal-to-noise ratio, fiber number, and fiber head location on the pipeline's redshift success rate. Finally, we describe directions of ongoing development

Composition of lower urinary tract stones in canines in Mexico City

11th International symposium on urolithiasis, Nice, France, 2–5 September 2008 Urological Research (2008) 36:157–232. doi:10.1007/s00240-008-0145-5. http://www.springerlink.com/ content/x263655772684210/fulltext.pdf.Effective long-term management of urolithiasis depends on identification and manipulation of factors contributing to initial stone formation; identification of these factors depends on accurate identification of the mineral composition of the urolith involved. The purpose of this study was to determine the chemical composition of uroliths obtained from the low urinary tract of dogs in Mexico City. One hundred and five cases of urolithiasis were studied in which stones were surgically obtained from the low urinary tracts of dogs treated in different hospitals. The chemical composition of the uroliths was quantita- tively and qualitatively determined by stereoscopic microscopy, IR-spectroscopy, scanning electron micros- copy and X-ray microanalysis. Age of animals ranged from 4 months to 14 years, with a median of 5 years. Compo- sition and distribution of the uroliths were struvite 38.1%,calcium oxalate 26.7%, silica 13.3%, urate 7.6%, mixed 11.4%, compounds 1.9%, and cystine 1%. Most uroliths were found in pure breed dogs (75.2%); 23 different breeds were identified, and more than half of the submissions were from breeds of small size. In our study, the frequency of struvite, calcium oxalate, cystine, urates, mixed and com- pounds stones are in agreement with papers that report on dog populations in America and Europe, but a higher fre- quency of silica uroliths was observed in Mexico City dogs.This work has been partially supported by a project of Waltham Foundation in Mexico

Metallicity gradient of the thick disc progenitor at high redshift

We have developed a novel Markov Chain Monte Carlo chemical 'painting' technique to explore possible radial and vertical metallicity gradients for the thick disc progenitor. In our analysis, we match an N-body simulation to the data from the Apache Point Observatory Galactic Evolution Experiment survey.We assume that the thick disc has a constant scaleheight and has completed its formation at an early epoch, after which time radial mixing of its stars has taken place. Under these assumptions, we find that the initial radial metallicity gradient of the thick disc progenitor should not be negative, but either flat or even positive, to explain the current negative vertical metallicity gradient of the thick disc. Our study suggests that the thick disc was built-up in an inside-out and upside-down fashion, and older, smaller and thicker populations are more metal poor. In this case, star-forming discs at different epochs of the thick disc formation are allowed to have different radial metallicity gradients, including a negative one, which helps to explain a variety of slopes observed in high-redshift disc galaxies. This scenario helps to explain the positive slope of the metallicity-rotation velocity relation observed for the Galactic thick disc. On the other hand, radial mixing flattens the slope of an existing gradient

The proteome of Toxoplasma gondii: integration with the genome provides novel insights into gene expression and annotation

A proteomics analysis identifies one third of the predicted Toxoplasma gondii proteins and integrates proteomics and genomics data to refine genome annotation

Role of Neural NO Synthase (nNOS) Uncoupling in the Dysfunctional Nitrergic Vasorelaxation of Penile Arteries from Insulin-Resistant Obese Zucker Rats

Objective: Erectile dysfunction (ED) is considered as an early sign of vascular disease due to its high prevalence in patients with cardiovascular risk factors. Endothelial and neural dysfunction involving nitric oxide (NO) are usually implicated in the pathophysiology of the diabetic ED, but the underlying mechanisms are unclear. The present study assessed the role of oxidative stress in the dysfunctional neural vasodilator responses of penile arteries in the obese Zucker rat (OZR), an experimental model of metabolic syndrome/prediabetes. Methods and Results: Electrical field stimulation (EFS) under non-adrenergic non-cholinergic (NANC) conditions evoked relaxations that were significantly reduced in penile arteries of OZR compared with those of lean Zucker rats (LZR). Blockade of NO synthase (NOS) inhibited neural relaxations in both LZR and OZR, while saturating concentrations of the NOS substrate L-arginine reversed the inhibition and restored relaxations in OZR to levels in arteries from LZR. nNOS expression was unchanged in arteries from OZR compared to LZR and nNOS selective inhibition decreased the EFS relaxations in LZR but not in OZR, while endothelium removal did not alter these responses in either strain. Superoxide anion production and nitro-tyrosine immunostaining were elevated in the erectile tissue from OZR. Treatment with the NADPH oxidase inhibitor apocynin or acute incubation with the NOS cofactor tetrahydrobiopterin (BH4) restored neural relaxations in OZR to levels in control arteries, while inhibition of the enzyme of BH4 synthesis GTP-cyclohydrolase (GCH) reduced neural relaxations i

Elogio que al Rey nuestro Señor D. Carlos III dixo en la Acta publica celebrada por la Real Sociedad de Amigos del Pais de Tenerife el dia 4 de noviembre de 1785

Fecha tomada del tit.Adornos tip. al principio y final del text

Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils

Copyright © 2009 European Geosciences Union. This is the published version available at http://www.biogeosciences.net/6/2759/2009/bg-6-2759-2009.html © Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License.The net primary productivity (NPP) of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1) How do Amazonian forests allocate productivity among its above- and below-ground components? (2) How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3MgC ha−1 yr−1 (mean±standard error), at a white sand plot, and 17.0±1.4MgC ha−1 yr−1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9MgC ha−1 yr−1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content