3,154 research outputs found

    Magnetized strange quark matter and magnetized strange quark stars

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    Strange quark matter could be found in the core of neutron stars or forming strange quark stars. As is well known, these astrophysical objects are endowed with strong magnetic fields which affect the microscopic properties of matter and modify the macroscopic properties of the system. In this paper we study the role of a strong magnetic field in the thermodynamical properties of a magnetized degenerate strange quark gas, taking into account beta-equilibrium and charge neutrality. Quarks and electrons interact with the magnetic field via their electric charges and anomalous magnetic moments. In contrast to the magnetic field value of 10^19 G, obtained when anomalous magnetic moments are not taken into account, we find the upper bound B < 8.6 x 10^17 G, for the stability of the system. A phase transition could be hidden for fields greater than this value.Comment: 9 pages, 9 figure

    The Giraffe Inner Bulge Survey (GIBS) II. Metallicity distributions and alpha element abundances at fixed Galactic latitude

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    High resolution (R\sim22,500) spectra for 400 red clump giants, in four fields within 4.8b3.4\rm -4.8^{\circ} \lesssim b \lesssim -3.4^{\circ} and 10l+10\rm -10^{\circ} \lesssim l \lesssim +10^{\circ}, were obtained within the GIRAFFE Inner Bulge Survey (GIBS) project. To this sample we added another \sim 400 stars in Baade's Window, observed with the identical instrumental configuration. We constructed the metallicity distributions for the entire sample, as well as for each field individually, in order to investigate the presence of gradients or field-to-field variations in the shape of the distributions. The metallicity distributions in the five fields are consistent with being drawn from a single parent population, indicating the absence of a gradient along the major axis of the Galactic bar. The global metallicity distribution is well fitted by two Gaussians. The metal poor component is rather broad, with a mean at =0.31\rm =-0.31 dex and σ=0.31\sigma=0.31 dex. The metal-rich one is narrower, with mean =+0.26\rm =+0.26 and σ=0.2\sigma=0.2 dex. The [Mg/Fe] ratio follows a tight trend with [Fe/H], with enhancement with respect to solar in the metal-poor regime, similar to the one observed for giant stars in the local thick disc. [Ca/Fe] abundances follow a similar trend, but with a considerably larger scatter than [Mg/Fe]. A decrease in [Mg/Fe] is observed at [Fe/H]=0.44\rm [Fe/H]=-0.44 dex. This \textit{knee} is in agreement with our previous bulge study of K-giants along the minor axis, but is 0.1 dex lower in metallicity than the one reported for the Bulge micro lensed dwarf and sub-giant stars. We found no variation in α\alpha-element abundance distributions between different fields.Comment: Accepted for publication in A&

    The GIRAFFE Inner Bulge Survey (GIBS). I. Survey Description and a kinematical map of the Milky Way bulge

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    The Galactic bulge is a massive, old component of the Milky Way. It is known to host a bar, and it has recently been demonstrated to have a pronounced boxy/peanut structure in its outer region. Several independent studies suggest the presence of more than one stellar populations in the bulge, with different origins and a relative fraction changing across the bulge area. This is the first of a series of papers presenting the results of the Giraffe Inner Bulge Survey, carried out at the ESO-VLT with the multifibre spectrograph FLAMES. Spectra of ~5000 red clump giants in 24 bulge fields have been obtained at resolution R=6500, in the infrared Calcium triplet wavelength region at 8500 {\AA}. They are used to derive radial velocities and metallicities, based on new calibration specifically devised for this project. Radial velocities for another ~1200 bulge red clump giants, obtained from similar archive data, have been added to the sample. Higher resolution spectra have been obtained for 450 additional stars at latitude b=-3.5, with the aim of investigating chemical abundance patterns variations with longitude, across the inner bulge. In total we present here radial velocities for 6392 RC stars. We derive a radial velocity, and velocity dispersion map of the Milky Way bulge, useful to be compared with similar maps of external bulges, and to infer the expected velocities and dispersion at any line of sight. The K-type giants kinematics is consistent with the cylindrical rotation pattern of M-giants from the BRAVA survey. Our sample enables to extend this result to latitude b=-2, closer to the Galactic plane than probed by previous surveys. Finally, we find strong evidence for a velocity dispersion peak at (0,-1) and (0,-2), possibly indicative of a high density peak in the central 250 pc of the bulgeComment: A&A in pres

    Sorption direct air capture with CO2 utilization

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    Direct air capture (DAC) is gathering momentum since it has vast potential and high flexibility to collect CO2 from discrete sources as “synthetic tree” when compared with current CO2 capture technologies, e.g., amine based post-combustion capture. It is considered as one of the emerging carbon capture technologies in recent decades and remains in a prototype investigation stage with many technical challenges to be overcome. The objective of this paper is to comprehensively discuss the state-of-the-art of DAC and CO2 utilization, note unresolved technology bottlenecks, and give investigation perspectives for commercial large-scale applications. Firstly, characteristics of physical and chemical sorbents are evaluated. Then, the representative capture processes, e.g., pressure swing adsorption, temperature swing adsorption and other ongoing absorption chemical loops, are described and compared. Methods of CO2 conversion including synthesis of fuels and chemicals as well as biological utilization are reviewed. Finally, techno-economic analysis and life cycle assessment for DAC application are summarized. Based on research achievements, future challenges of DAC and CO2 conversion are presented, which include providing synthesis guidelines for obtaining sorbents with the desired characteristics, uncovering the mechanisms for different working processes and establishing evaluation criteria in terms of technical and economic aspects

    Impact of Implementing a Dyslipidemia Management Guideline on Cholesterol Control for Secondary Prevention of Ischemic Heart Disease in Primary Care

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    Cardiovascular diseases (CVD) are the main cause of death worldwide. The control of CVD risk factors, such as dyslipidemia, reduces their mortality rate. Nonetheless, fewer than 50% of patients with ischemic heart disease (IHD) have good cholesterol control. Our objective is to assess whether the level of participation of general practitioners (GPs) in activities to implement a dyslipidemia management guideline, and the characteristics of the patient and physician are associated with cholesterol control in IHD patients. We undertook a quasi-experimental, uncontrolled, before-and-after study of 1151 patients. The intervention was carried out during 2010 and 2011, and consisted of a face-to-face training and online course phase (Phase 1), and another of face-to-face feedback (Phase 2). The main outcome variable was the low-density lipoprotein cholesterol (LDL-C) control, whereby values of <100 mg/dL (2.6 mmol/L) were set as a good level of control, according to the recommendations of the guidelines in force in 2009. After Phase 1, 6.7% more patients demonstrated good cholesterol control. With respect to patient characteristics, being female and being older were found to be risk factors of poor control. Being diabetic and having suffered a stroke were protective factors. Of the GPs' characteristics, being tutor in a teaching center for GP residents and having completed the online course were found to be protective factors. We concluded that cholesterol control in IHD patients was influenced by the type of training activity undertook by physicians during the implementation of the GPC, and patient and physician characteristics. We highlight that if we apply the recent targets of the European guideline, which establish a lower level of LDL-C control, the percentage of good control could be worse than the observed in this study

    Solar photocatalytic degradation of polyethylene terephthalate nanoplastics: Evaluation of the applicability of the TiO2/MIL-100(Fe) composite material

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    For the first time, TiO2/MIL-100(Fe) photocatalysts supported on perlite mineral particles prepared by the solvothermal/microwave methods and post-annealing technique were tested in the degradation of polyethylene terephthalate nanoplastics (PET NPs). Powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, N2 physisorption, photoluminescence emission spectroscopy, photocurrent response, and electrochemical impedance spectroscopy were used to characterize the as-prepared materials. The response surface methodology approach was used to study the effects: pH of the NPs suspension and incorporated amount of MIL-100(Fe) on the TiO2/MIL-100(Fe) catalyst to optimize the photocatalytic degradation of the PET NPs under simulated solar light. The degradation of the PET NPs was evaluated by measuring turbidity and carbonyl index (FTIR) changes. The total organic carbon (TOC) in the solution during the degradation of the PET NPs was assessed to measure NPs oxidation into water-soluble degradation by-products. The active species involved in the photocatalytic degradation of PET NPs by the TiO2/MIL-100(Fe) composite was further examined based on trapping experiments. The use of 12.5 wt% TiO2/MIL-100(Fe) catalyst showed improved photocatalytic efficacy in the oxidation of PET NPs at pH 3 under simulated sunlight compared to bare TiO2. The increase in the carbonyl index (CI = 0.99), the reduction in the turbidity ratio (0.454), and the increase in the content of TOC released (3.00 mg/L) were possible with 12.5 wt% TiO2/MIL-100(Fe) material. In contrast, the PET NPs were slowly degraded by TiO2-based photocatalysis (CI = 0.96, turbidity ratio = 0.539, released TOC = 2.12 mg/L). The mesoporous TiO2/MIL-100(Fe) composites with high specific surface area, capacity to absorb visible light, and effective separation of photogenerated electron-hole charges clearly demonstrated the enhancement of the photocatalytic performance in the PET NPs degradation under simulated solar light

    Alcohol and early mortality (before 65 years) in the ‘seguimiento Universidad de Navarra’ (SUN) cohort: does any level reduce mortality?

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    The aim of this study was to assess the association between alcohol intake and premature mortality (younger than 65 years) and to explore the effect of potential alcohol underreporting by heavy drinkers. We followed-up 20 272 university graduates. Four categories of alcohol intake were considered (abstainer, light, moderate and heavy consumption). Repeated measurements of alcohol intake and updated information on confounders were used in time-dependent Cox models. Potential underreporting of alcohol intake by some heavy drinkers (likely misclassified as light or moderate drinkers) was explicitly addressed in an attempt to correct potential underreporting by using indirect information. During 12·3 years of median follow-up (interquartile range: 6·8–15·0), 226 participants died before their 65th birthday. A higher risk of early mortality was found for the highest category of alcohol intake (≥50 g/d) in comparison with abstention (multivariable-adjusted hazard ratio (HR) = 2·82, 95 % CI 1·38, 5·79). In analyses of alcohol as a continuous variable, the multivariable-adjusted HR was 1·17 (95 % CI 1·08, 1·26), for each 10 g/d of alcohol. This harmful linear association was present both in uncorrected models and in models corrected for potential underreporting. No significant inverse association between light or moderate alcohol intake and premature mortality was observed, even after correcting for potential misclassification. Alcohol intake exhibited a harmful linear dose–response association with premature mortality (<65 years) in this young and highly educated Mediterranean cohort. Our attempts to correct for potential misclassification did not substantially change these results

    Online Global Learning in Direct Fuzzy Controllers

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    The atypical CDK activator RingoA/Spy1 regulates exit from quiescence in neural stem cells

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    In the adult mammalian brain, most neural stem cells (NSCs) are held in a reversible state of quiescence, which is essential to avoid NSC exhaustion and determine the appropriate neurogenesis rate. NSCs of the mouse adult subependymal niche provide neurons for olfactory circuits and can be found at different depths of quiescence, but very little is known on how their quiescence-to-activation transition is controlled. Here, we identify the atypical cyclin-dependent kinase (CDK) activator RingoA as a regulator of this process. We show that the expression of RingoA increases the levels of CDK activity and facilitates cell cycle entry of a subset of NSCs that divide slowly. Accordingly, RingoA-deficient mice exhibit reduced olfactory neurogenesis with an accumulation of quiescent NSCs. Our results indicate that RingoA plays an important role in setting the threshold of CDK activity required for adult NSCs to exit quiescence and may represent a dormancy regulator in adult mammalian tissues.© 2023 The Author(s)

    Development of an enhanced health-economic model and cost-effectiveness analysis of tiotropium + olodaterol Respimat® fixed-dose combination for chronic obstructive pulmonary disease patients in Italy

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    Background: The objective of this study was to compare the cost-effectiveness of the fixed-dose combination (FDC) of tiotropium + olodaterol Respimat® FDC with tiotropium alone for patients with chronic obstructive pulmonary disease (COPD) in the Italian health care setting using a newly developed patient-level Markov model that reflects the current understanding of the disease. Methods: While previously published models have largely been based around a cohort approach using a Markov structure and GOLD stage stratification, an individual-level Markov approach was selected for the new model. Using patient-level data from the twin TOnado trials assessing Tiotropium + olodaterol Respimat® FDC versus tiotropium, outcomes were modelled based on the trough forced expiratory volume (tFEV1) of over 1000 patients in each treatment arm, tracked individually at trial visits through the 52-week trial period, and after the trial period it was assumed to decline at a constant rate based on disease stage. Exacerbation risk was estimated based on a random-effects logistic regression analysis of exacerbations in UPLIFT. Mortality by age and disease stage was estimated from an analysis of TIOSPIR trial data. Cost of bronchodilators and other medications, routine management, and costs of treatment for moderate and severe exacerbations for the Italian setting were included. A cost-effectiveness analysis was conducted over a 15-year time horizon from the perspective of the Italian National Health Service. Results: Aggregating total costs and quality-adjusted life years (QALYs) for each treatment cohort over 15 years and comparing tiotropium + olodaterol Respimat® FDC with tiotropium alone, resulted in mean incremental co
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