3,472 research outputs found

    Contribution of point sources to the soft gamma-ray Galactic emission

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    The nature of the soft gamma-ray (20-200 keV) Galactic emission has been a matter of debate for a long time. Previous experiments have tried to separate the point source contribution from the real interstellar emission, but with a rather poor spatial resolution, they concluded that the interstellar emission could be a large fraction of the total Galactic emission. INTEGRAL, having both high resolution and high sensitivity, is well suited to reassess more precisely this problem. Using the INTEGRAL core program Galactic Center Deep Exposure (GCDE), we estimate the contribution of detected point sources to the total Galactic flux.Comment: Proceedings of the 5th INTEGRAL Workshop, Munich 16-20 February 2004. ESA SP-55

    Prospective CO2 and CO bioconversion into ectoines using novel microbial platforms

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    Microbial conversion of CO2 and CO into chemicals is a promising route that can contribute to the cost-effective reduction of anthropogenic green house and waste gas emissions and create a more circular economy. However, the biotechnological valorization of CO2 and CO into chemicals is still restricted by the limited number of model microorganisms implemented, and the small profit margin of the products synthesized. This perspective paper intends to explore the genetic potential for the microbial conversion of CO2 and CO into ectoines, in a tentative to broaden bioconversion platforms and the portfolio of products from C-1 gas fermentations. Ectoine and hydroxyectoine can be produced by microorganisms growing at high salinity. They are high-value commodities for the pharmaceutical and medical sectors (1000-1200 euro/kg). Currently microbial ectoine production is based on sugar fermentations, but expansion to other more sustainable and cheaper substrates is desirable. In this work, a literature review to identify halophilic microbes able to use CO2 and CO as a carbon source was performed. Subsequently, genomes of this poll of microbes were mined for genes that encode for ectoine and hydroxyectoine synthesis (ectABCD, ask, asd and ask_ect). As a result, we identified a total of 31 species with the genetic potential to synthesize ectoine and 14 to synthesize hydroxyectoine. These microbes represent the basis for the creation of novel microbial-platforms that can promote the development of cost-effective and sustainable valorization chains of CO2 and CO in different industrial scenarios

    The puzzling origin of the 6Li plateau

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    We discuss the 6Li abundance evolution within a hierarchical model of Galaxy formation which correctly reproduces the [Fe/H] distribution of metal-poor halo stars. Contrary to previous findings, we find that neither the level (6Li/H=6x10^-12) nor the flatness of the 6Li distribution with [Fe/H] can be reproduced under the most favourable conditions by any model in which 6Li production is tied to a (data-constrained) Galactic star formation rate via cosmic ray spallation. Thus, the origin of the plateau might be due to some other early mechanism unrelated to star formation.Comment: 6 pages, 3 figures, accepted for publication in MNRAS Letter

    Search for Dark Matter with GLAST

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    The detection of exotic cosmic rays due to pair annihilation of dark matter particles in the Milky Way halo is a viable techniques to search for supersymmetric dark matter candidates. The study of the spectrum of gamma-rays, antiprotons and positrons offers good possibilities to perform this search in a significant portion of the Minimal Supersymmetric Standard Model parameter space. In particular the EGRET team have seen a convincing signal for a strong excess of emission from the Galactic center that has no simple explanation with standard processes. We will review the limits achievable with the experiment GLAST taking into accounts the LEP results and we will compare this method with the antiproton and positrons experiments.Comment: 8 pages, 12 figures, Invited talk at the First International Workshop on Fundamental and Particle Physics in Space, Space Part, May 14-19 2002, Isola d'Elba. V2: one figure updated, references adde

    Background and Method of the Striving to be Strong Study a RCT Testing the Efficacy of a M-health Self-management Intervention

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    Background Osteoporosis is a prevalent and debilitating condition affecting \u3e50% of post-menopausal women. Yet, a low percentage of women regularly engage in health promoting behaviors associated with osteoporosis prevention. Complex, multidimensional, m-Health interventions hold promise to effect engagement in health behavior change related to calcium and vitamin D intake, balance, core and leg strength, and physical activity. Methods Striving to be Strong study (R01NR013913-01) tests the efficacy of a research and theory based, patient centered, dynamically tailored intervention delivered via smart phone apps. Ecological Momentary Assessments (EMAs) enhance immediate feedback and complement traditional measures. The desired outcomes are the maintenance of osteoporosis self-management behaviors and a decrease in the loss of bone density over time. The Individual and Family Self-management Theory provided the conceptual foundation for the study. The sample consists of 290 healthy women between the ages of 40 and 60 with an anticipated attrition of 33%. This three group repeated measures Randomized Clinical Trial spans a 12-month time period. Data collected occurs via web site, smart-phone app, self-report, observation, and measures. Proximal (engagement in osteoporosis health behaviors) and distal (serum vitamin D, DXA, and body composition) outcomes are collected for testing of the efficacy of the intervention and theory evaluation. Discussion Active and rigorous quality management processes continually evaluate enrollment and retention goals, functionality of the automated intervention delivery and data collection systems, EMAs, and dispersion of incentives

    Broadband maps of eROSITA and their comparison with the ROSAT survey

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    By June of 2020, the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) on board the Spectrum Roentgen Gamma observatory had completed its first of the planned eight X-ray all-sky survey (eRASS1). The large effective area of the X-ray telescope makes it ideal for a survey of the faint X-ray diffuse emission over half of the sky with an unprecedented energy resolution and position accuracy. In this work, we produce the X-ray diffuse emission maps of the eRASS1 data with a current calibration, covering the energy range from 0.2 to 8.0 keV. We validated these maps by comparison with X-ray background maps derived from the ROSAT All Sky Survey (RASS). We generated X-ray images with a pixel area of 9 arcmin2^2 using the observations available to the German eROSITA consortium. The contribution of the particle background to the photons was subtracted from the final maps. We also subtracted all the point sources above a flux threshold dependent on the goal of the subtraction, exploiting the eRASS1 catalog that will soon be available. The accuracy of the eRASS1 maps is shown by a flux match to the RASS X-ray maps, obtained by converting the eROSITA rates into equivalent ROSAT count rates in the standard ROSAT energy bands R4, R5, R6, and R7, within 1.25σ\sigma. We find small residual deviations in the R4, R5, and R6 bands, where eROSITA tends to observe lower flux than ROSAT (~11%), while a better agreement is achieved in the R7 band (~1%). The eRASS maps exhibit lower noise levels than RASS maps at the same resolution above 0.3 keV. We report the average surface brightness and total flux of different large sky regions as a reference. The detection of faint emission from diffuse hot gas in the Milky Way is corroborated by the consistency of the eRASS1 and RASS maps shown in this paper and by their comparable flux dynamic range.Comment: A&A, in press. 27 pages; 26 figures; 3 table

    Anti-müllerian hormone is not associated with cardiometabolic risk factors in adolescent females

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    <p>Objectives: Epidemiological evidence for associations of Anti-Müllerian hormone (AMH) with cardiometabolic risk factors is lacking. Existing evidence comes from small studies in select adult populations, and findings are conflicting. We aimed to assess whether AMH is associated with cardiometabolic risk factors in a general population of adolescent females.</p> <p>Methods: AMH, fasting insulin, glucose, HDLc, LDLc, triglycerides and C-reactive protein (CRP) were measured at a mean age 15.5 years in 1,308 female participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Multivariable linear regression was used to examine associations of AMH with these cardiometabolic outcomes.</p> <p>Results: AMH values ranged from 0.16–35.84 ng/ml and median AMH was 3.57 ng/ml (IQR: 2.41, 5.49). For females classified as post-pubertal (n = 848) at the time of assessment median (IQR) AMH was 3.81 ng/ml (2.55, 5.82) compared with 3.25 ng/ml (2.23, 5.05) in those classed as early pubertal (n = 460, P≤0.001). After adjusting for birth weight, gestational age, pubertal stage, age, ethnicity, socioeconomic position, adiposity and use of hormonal contraceptives, there were no associations with any of the cardiometabolic outcomes. For example fasting insulin changed by 0% per doubling of AMH (95%CI: −3%,+2%) p = 0.70, with identical results if HOMA-IR was used. Results were similar after additional adjustment for smoking, physical activity and age at menarche, after exclusion of 3% of females with the highest AMH values, after excluding those that had not started menarche and after excluding those using hormonal contraceptives.</p> <p>Conclusion: Our results suggest that in healthy adolescent females, AMH is not associated with cardiometabolic risk factors.</p&gt

    DOPAL initiates αSynuclein-dependent impaired proteostasis and degeneration of neuronal projections in Parkinson’s disease

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    Dopamine dyshomeostasis has been acknowledged among the determinants of nigrostriatal neuron degeneration in Parkinson’s disease (PD). Several studies in experimental models and postmortem PD patients underlined increasing levels of the dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL), which is highly reactive towards proteins. DOPAL has been shown to covalently modify the presynaptic protein αSynuclein (αSyn), whose misfolding and aggregation represent a major trait of PD pathology, triggering αSyn oligomerization in dopaminergic neurons. Here, we demonstrated that DOPAL elicits αSyn accumulation and hampers αSyn clearance in primary neurons. DOPAL-induced αSyn buildup lessens neuronal resilience, compromises synaptic integrity, and overwhelms protein quality control pathways in neurites. The progressive decline of neuronal homeostasis further leads to dopaminergic neuron loss and motor impairment, as showed in in vivo models. Finally, we developed a specific antibody which detected increased DOPAL-modified αSyn in human striatal tissues from idiopathic PD patients, corroborating the translational relevance of αSyn-DOPAL interplay in PD neurodegeneration

    The Galactic Center as a Dark Matter Gamma-Ray Source

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    The EGRET telescope has identified a gamma-ray source at the Galactic center. We point out here that the spectral features of this source are compatible with the gamma-ray flux induced by pair annihilations of dark matter weakly interacting massive particles (WIMPs). We show that the discrimination between this interpretation and other viable explanations will be possible with GLAST, the next major gamma-ray telescope in space, on the basis of both the spectral and the angular signature of the WIMP-induced component. If, on the other hand, the data will point to an alternative explanation, we prove that there will still be the possibility for GLAST to single out a weaker dark matter source at the Galactic center. The potential of GLAST has been explored both in the context of a generic simplified toy-model for WIMP dark matter, and in a more specific setup, the case of dark matter neutralinos in the minimal supergravity framework. In the latter, we find that even in the case of moderate dark matter densities in the Galactic center region, there are portions of the parameter space which will be probed by GLAST.Comment: 26 pages, 22 eps figures, v2: + 2 new figures, Version accepted by Astroparticle Physic
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