329 research outputs found

    Insights from super-metal-rich stars: Is the Milky Way bar young?

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    Context. Bar formation and merger events can contribute to the rearrangement of stars within the Galaxy in addition to triggering star formation (SF) epochs. Super-metal-rich (SMR) stars found in the solar neighbourhood (SNd) can be used as tracers of such events as they are expected to originate only in the inner Galaxy and to have definitely migrated. Aims. We study a homogeneous and large sample of SMR stars in the SNd to provide tighter constraints on the epoch of the bar formation and its impact on the Milky Way (MW) disc stellar populations. Methods. We investigated a sample of 169 701 main sequence turnoff (MSTO) and subgiant branch (SGB) stars with 6D phase space information and high-quality stellar parameters coming from the hybrid-CNN analysis of the Gaia-DR3 RVS stars. We computed distances and ages using the StarHorse code with a mean precision of 1% and 11%, respectively. Of these stars, 11 848 have metallicity ([Fe/H]) above 0.15 dex. Results. We report a metallicity dependence of spatial distribution of stellar orbits shown by the bimodal distribution in the guiding radius (Rg) at 6.9 and 7.9 kpc, first appearing at [Fe/H] ~ 0.1 dex, becoming very pronounced at higher [Fe/H]. In addition, we observe a trend where the most metal-rich stars, with [Fe/H] ~ 0.4 dex, are predominantly old (9–12 Gyr), but show a gradual decline in [Fe/H] with age, reaching approximately 0.25 dex about 4 Gyr ago, followed by a sharp drop around 3 Gyr ago. Furthermore, our full dataset reveals a clear peak in the age–metallicity relationship during the same period, indicating a SF burst around 3–4 Gyr ago with slightly sub-solar [Fe/H] and enhanced [α/Fe]. Conclusions. We show that the SMR stars are good tracers of bar activity.We interpret the steep decrease in the number of SMR stars at around 3 Gyr as the end of the bar formation epoch. In this scenario the peak of bar activity also coincides with a peak in the SF activity in the disc. Although the SF burst around 3 Gyr ago has been reported previously, its origin was unclear. Here we suggest that the SF burst was triggered by the high bar activity, 3–4 Gyr ago. According to these results and interpretation, the MW bar could be young

    Direct and indirect effects of planning density, nitrogenous fertilizer and host plant resistance on rice herbivores and their natural enemies

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    In rice ecosystems, seeding densities can be adjusted to compensate for lower nitrogen levels that reduce GHG emissions, or to increase farm profitability. However, density-induced changes to plant anatomy could affect herbivore-rice interactions, and alter arthropod community dynamics. We conducted an experiment that varied transplanting density (low or high), nitrogenous fertilizer (0, 60 or 150 kg added ha−1) and rice variety (resistant or susceptible to phloem-feeding insects) over two rice-growing seasons. Yields per plot increased with added nitrogen, but were not affected by variety or transplanting density. Planthopper and leafhopper densities were lower on resistant rice and in high-density field plots. Nitrogen was associated with higher densities of planthoppers, but lower densities of leafhoppers per plot. High planting densities and high nitrogen also increased rodent damage. The structure of arthropod herbivore communities was largely determined by season and transplanting density. Furthermore, two abundant planthoppers (Sogatella furcifera (Horváth) and Nilaparvata lugens (Stål)) segregated to low and high-density plots, respectively. The structure of decomposer communities was determined by season and fertilizer regime; total decomposer abundance increased in high-nitrogen plots during the dry season. Predator community structure was determined by season and total prey abundance (including decomposers) with several spider species dominating in plots with high prey abundance during the wet season. Our results indicate how rice plasticity and arthropod biodiversity promote stability and resilience in rice ecosystems. We recommend that conservation biological control, which includes a reduction or elimination of insecticides, could be promoted to attain sustainable rice production systems.info:eu-repo/semantics/publishedVersio

    Comparative study of paediatric prescription drug utilization between the spanish and immigrant population

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    <p>Abstract</p> <p>Background</p> <p>The immigrant population has increased greatly in Spain in recent years to the point where immigrants made up 12% of the infant population in 2008. There is little information available on the profile of this group with regard to prescription drug utilization in universal public health care systems such as that operating in Spain. This work studies the overall and specific differences in prescription drug utilization between the immigrant and Spanish population.</p> <p>Methods</p> <p>Use was made of the Aragonese Health Service databases for 2006. The studied population comprises 159,908 children aged 0-14 years, 13.6% of whom are foreign nationals. Different utilization variables were calculated for each group. Prescription-drug consumption is measured in Defined Daily Doses (DDD) and DDD/1000 persons/day/(DID).</p> <p>Results</p> <p>A total of 833,223 prescriptions were studied. Utilization is lower for immigrant children than in Spanish children for both DID (66.27 v. 113.67) and average annual expense (€21.55 v. €41.14). Immigrant children consume fewer prescription drugs than Spanish children in all of the therapy groups, with the most prescribed (in DID) being: respiratory system, anti-infectives for systemic use, nervous system, sensory organs. Significant differences were observed in relation to the type of drugs and the geographical background of immigrants.</p> <p>Conclusion</p> <p>Prescription drug utilization is much greater in Spanish children than in immigrant children, particularly with reference to bronchodilators (montelukast and terbutaline) and attention-disorder hyperactivity drugs such as methylphenidate. There are important differences regarding drug type and depending on immigrants' geographical backgrounds that suggest there are social, cultural and access factors underlying these disparities.</p

    Atypical Mg-poor Milky Way Field Stars with Globular Cluster Second-generation-like Chemical Patterns

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    We report the peculiar chemical abundance patterns of 11 atypical Milky Way (MW) field red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). These atypical giants exhibit strong Al and N enhancements accompanied by C and Mg depletions, strikingly similar to those observed in the so-called second-generation (SG) stars of globular clusters (GCs). Remarkably, we find low Mg abundances ([Mg/Fe] < 0.0) together with strong Al and N overabundances in the majority (5/7) of the metal-rich ([Fe/H] gsim −1.0) sample stars, which is at odds with actual observations of SG stars in Galactic GCs of similar metallicities. This chemical pattern is unique and unprecedented among MW stars, posing urgent questions about its origin. These atypical stars could be former SG stars of dissolved GCs formed with intrinsically lower abundances of Mg and enriched Al (subsequently self-polluted by massive AGB stars) or the result of exotic binary systems. We speculate that the stars Mg-deficiency as well as the orbital properties suggest that they could have an extragalactic origin. This discovery should guide future dedicated spectroscopic searches of atypical stellar chemical patterns in our Galaxy, a fundamental step forward to understanding the Galactic formation and evolution

    Healthy dietary indices and risk of depressive outcomes : a systematic review and meta-analysis of observational studies

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    With depression being the psychiatric disorder incurring the largest societal costs in developed countries, there is a need to gather evidence on the role of nutrition in depression, to help develop recommendations and guide future psychiatric health care. The aim of this systematic review was to synthesize the link between diet quality, measured using a range of predefined indices, and depressive outcomes. Medline, Embase and PsychInfo were searched up to 31st May 2018 for studies that examined adherence to a healthy diet in relation to depressive symptoms or clinical depression. Where possible, estimates were pooled using random effect meta-analysis with stratification by observational study design and dietary score. A total of 20 longitudinal and 21 cross-sectional studies were included. These studies utilized an array of dietary measures, including: different measures of adherence to the Mediterranean diet, the Healthy Eating Index (HEI) and Alternative HEI (AHEI), the Dietary Approaches to Stop Hypertension, and the Dietary Inflammatory Index. The most compelling evidence was found for the Mediterranean diet and incident depression, with a combined relative risk estimate of highest vs. lowest adherence category from four longitudinal studies of 0.67 (95% CI 0.55-0.82). A lower Dietary Inflammatory Index was also associated with lower depression incidence in four longitudinal studies (relative risk 0.76; 95% CI: 0.63-0.92). There were fewer longitudinal studies using other indices, but they and cross-sectional evidence also suggest an inverse association between healthy diet and depression (e.g., relative risk 0.65; 95% CI 0.50-0.84 for HEI/AHEI). To conclude, adhering to a healthy diet, in particular a traditional Mediterranean diet, or avoiding a pro-inflammatory diet appears to confer some protection against depression in observational studies. This provides a reasonable evidence base to assess the role of dietary interventions to prevent depression.Peer reviewe

    Longitudinal Analysis of the Temporal Evolution of Acinetobacter baumannii Strains in Ohio, USA, by Using Rapid Automated Typing Methods

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    Genotyping methods are essential to understand the transmission dynamics of Acinetobacter baumannii. We examined the representative genotypes of A. baumannii at different time periods in select locations in Ohio, using two rapid automated typing methods: PCR coupled with electrospray ionization mass spectrometry (PCR/ESI-MS), a form of multi-locus sequence typing (MLST), and repetitive-sequence-based-PCR (rep-PCR). Our analysis included 122 isolates from 4 referral hospital systems, in 2 urban areas of Ohio. These isolates were associated with outbreaks at 3 different time periods (1996, 2000 and 2005–2007). Type assignments of PCR/ESI-MS and rep-PCR were compared to each other and to worldwide (WW) clone types. The discriminatory power of each method was determined using the Simpson's index of diversity (DI). We observed that PCR/ESI-MS sequence type (ST) 14, corresponding to WW clone 3, predominated in 1996, whereas ST 12 and 14 co-existed in the intermediate period (2000) and ST 10 and 12, belonging to WW clone 2, predominated more recently in 2007. The shift from WW clone 3 to WW clone 2 was accompanied by an increase in carbapenem resistance. The DI was approximately 0.74 for PCR/ESI-MS, 0.88 for rep-PCR and 0.90 for the combination of both typing methods. We conclude that combining rapid automated typing methods such as PCR/ESI-MS and rep-PCR serves to optimally characterize the regional molecular epidemiology of A. baumannii. Our data also sheds light on the changing sequence types in an 11 year period in Northeast Ohio

    La sustitución C>A en el NT 46 en la región 3’ UTR (Alfa Complex Protected Region) del gen ALFA 1 de globina ¿mutación o polimorfismo?

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    PC-048 Antecedentes: Las regiones no traducidas [UnTranslated Region (UTR)] desempeñan un papel crucial en la regulación postranscripcional de la expresión génica, incluida la modulación del transporte de ARNm fuera del núcleo, la eficacia de la traducción, la localización subcelular y la estabilidad. La estabilidad del ARNm es un factor decisivo para el desarrollo y funcionamiento normal de los glóbulos rojos. En el caso del ARNm de a-globina, los principales determinantes de la estabilidad se localizan en el extremo 3’ UTR; en concreto, se han identificado 3 áreas discontinuas ricas en citosina (C) ubicadas entre los nucleótidos (nt) 25 y 70 corriente abajo del codon de parada. Estas áreas ricas en C son responsables de atraer a una ribonucleoproteína (RNP) llamada a-globina poli (C) de unión o a-complejo proteína (aCP) para estabilizar la molécula de ARNm. Wagoner et al. demostraron a través del análisis in vitro que cualquier mutación en estos elementos ricos en C dificulta la unión del ARNm de a-globina con el aCP y desestabiliza al ARNm. Objetivos: Presentamos 15 pacientes con la sustitución C>A en el extremo 3’UTR del gen a1 de globina, localizada en la región del complejo a (aCP), la cual podría causar a-talasemia no deleción al afectar a la estabilidad postranscripcional (estabilidad del ARNm) o tratarse de un polimorfismo. Métodos: Se han estudiado 15 pacientes pertenecientes a 12 familias, todas de origen español excepto dos, una procedente de Rumanía y otra de Marruecos. Las edades estuvieron comprendidas entre 2 y 67 años. Todos fueron estudiados por presentar microcitosis e hipocromía sin ..
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