151 research outputs found

    Multimegawatt Power Sources For Commercial Space Operations

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    The commercialization of space will require power for everything from lights to climate control and especially for the industrial processes that are planned to take advantage of the zero-g environment. This power requirement can vary from a few kilowatts to several megewatts, depending on the particular commercial operation. This paper discusses the concepts that are available to supply this power, the different ways the power might be utilized, and some of the problems associated with development and utilization of the power source

    L'Ecostratigrafia i la seva problemàtica

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    This is a brief analysis about ecostratigraphy, based on bibliographical as well as personal inquiries on the subject

    DNA methylation partially mediates antidiabetic effects of metformin on HbA1c levels in individuals with type 2 diabetes

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    Aims: Despite metformin being used as first-line pharmacological therapy for type 2 diabetes, its underlying mechanisms remain unclear. We aimed to determine whether metformin altered DNA methylation in newlydiagnosed individuals with type 2 diabetes. Methods and Results: We found that metformin therapy is associated with altered methylation of 26 sites in blood from Scandinavian discovery and replication cohorts (FDR < 0.05), using MethylationEPIC arrays. The majority (88%) of these 26 sites were hypermethylated in patients taking metformin for ~ 3 months compared to controls, who had diabetes but had not taken any diabetes medication. Two of these blood-based methylation markers mirrored the epigenetic pattern in muscle and adipose tissue (FDR < 0.05). Four type 2 diabetes-associated SNPs were annotated to genes with differential methylation between metformin cases and controls, e.g., GRB10, RPTOR, SLC22A18AS and TH2LCRR. Methylation correlated with expression in human islets for two of these genes. Three metformin-associated methylation sites (PKNOX2, WDTC1 and MICB) partially mediate effects of metformin on follow-up HbA1c levels. When combining methylation of these three sites into a score, which was used in a causal mediation analysis, methylation was suggested to mediate up to 32% of metformin’s effects on HbA1c. Conclusion: Metformin-associated alterations in DNA methylation partially mediates metformin’s antidiabetic effects on HbA1c in newly-diagnosed individuals with type 2 diabetes

    Small mammals from the middle pleistocene layers of the sima del elefante (Sierra de Atapuerca, Burgos, northwestern Spain)

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    The Sima del Elefante site, located in the Sierra de Atapuerca (Burgos, Spain), is an important Pleistocene archaeopalaeontological locality that has been excavated every year since 1996. At least two main infill phases have been identified: a first (TELRU) early Pleistocene phase that has provided a rich faunal assemblage, various stone tools and the earliest human remains from western Europe; and a second phase (TEURU) attributed to the Middle Pleistocene. In this paper, for the first time we present a description of the TEURU small-mammal assemblage and its subsequent biochronological, palaeoenvironmental and palaeoclimatic implications. The small-mammal assemblage is highly diverse and comprises at least 17 species: 3 insectivores (cf. Erinaceus sp., Crocidura sp. and Sorex sp.); 4 chiropters (Rhinolophus ferrumequinum, Rhinolophus gr. euryale-mehelyi, Myotis gr. Myotisoxygnathus and Miniopteurs schreibersii); 9 rodents (Myodes glareolus, Microtus arvalis, Microtus agrestis, Iberomys brecciensis, Terricola cf. atapuerquensis, Arvicola sp., Apodemus sylvaticus, Eliomys quercinus and Allocricetus bursae) and 1 lagomorph (Oryctolagus sp.). Such an association suggests a late Middle Pleistocene age (ca. 250-350 ka), a patchy landscape dominated by humid meadows and woodland areas, and mild climatic conditions. These results are compared with other proxies, such as the herpetofauna, malacofauna, large-mammals and charcoals, providing a new scenario for the climatic and environmental conditions that prevailed during the latest Middle Pleistocene in the Sierra de Atapuerca

    Coffee consumption, genetic susceptibility and risk of latent autoimmune diabetes in adults : A population-based case-control study

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    Export Date: 31 October 2018Aim. - Coffee consumption is inversely related to risk of type 2 diabetes (T2D). In contrast, an increased risk of latent autoimmune diabetes in adults (LADA) has been reported in heavy coffee consumers, primarily in a subgroup with stronger autoimmune characteristics. Our study aimed to investigate whether coffee consumption interacts with HLA genotypes in relation to risk of LADA. Methods. - This population-based study comprised incident cases of LADA (n = 484) and T2D (n = 1609), and also 885 healthy controls. Information on coffee consumption was collected by food frequency questionnaire. Odds ratios (ORs) with 95% CIs of diabetes were calculated and adjusted for age, gender, BMI, education level, smoking and alcohol intake. Potential interactions between coffee consumption and high-risk HLA genotypes were calculated by attributable proportion (AP) due to interaction. Results. - Coffee intake was positively associated with LADA in carriers of high-risk HLA genotypes (OR: 1.14 per cup/day, 95% CI: 1.02-1.28), whereas no association was observed in non-carriers (OR: 1.04, 95% CI: 0.93-1.17). Subjects with both heavy coffee consumption (>= 4 cups day) and high-risk HLA genotypes had an OR of 5.74 (95% Cl: 3.34-9.88) with an estimated AP of 0.36 (95% CI: 0.01-0.71; P = 0.04370). Conclusion. - Our findings suggest that coffee consumption interacts with HLA to promote LADA. (C) 2018 Elsevier Masson SAS. All rights reserved.Peer reviewe

    App-based COVID-19 syndromic surveillance and prediction of hospital admissions in COVID Symptom Study Sweden

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    The app-based COVID Symptom Study was launched in Sweden in April 2020 to contribute to real-time COVID-19 surveillance. We enrolled 143,531 study participants (≥18 years) who contributed 10.6 million daily symptom reports between April 29, 2020 and February 10, 2021. Here, we include data from 19,161 self-reported PCR tests to create a symptom-based model to estimate the individual probability of symptomatic COVID-19, with an AUC of 0.78 (95% CI 0.74–0.83) in an external dataset. These individual probabilities are employed to estimate daily regional COVID-19 prevalence, which are in turn used together with current hospital data to predict next week COVID-19 hospital admissions. We show that this hospital prediction model demonstrates a lower median absolute percentage error (MdAPE: 25.9%) across the five most populated regions in Sweden during the first pandemic wave than a model based on case notifications (MdAPE: 30.3%). During the second wave, the error rates are similar. When we apply the same model to an English dataset, not including local COVID-19 test data, we observe MdAPEs of 22.3% and 19.0% during the first and second pandemic waves, respectively, highlighting the transferability of the prediction model

    A Genetic Basis of Susceptibility to Acute Pyelonephritis

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    For unknown reasons, urinary tract infections (UTIs) are clustered in certain individuals. Here we propose a novel, genetically determined cause of susceptibility to acute pyelonephritis, which is the most severe form of UTI. The IL-8 receptor, CXCR1, was identified as a candidate gene when mIL-8Rh mutant mice developed acute pyelonephritis (APN) with severe tissue damage.We have obtained CXCR1 sequences from two, highly selected APN prone patient groups, and detected three unique mutations and two known polymorphisms with a genotype frequency of 23% and 25% compared to 7% in controls (p<0.001 and p<0.0001, respectively). When reflux was excluded, 54% of the patients had CXCR1 sequence variants. The UTI prone children expressed less CXCR1 protein than the pediatric controls (p<0.0001) and two sequence variants were shown to impair transcription.The results identify a genetic innate immune deficiency, with a strong link to APN and renal scarring

    Drilling Predation on Serpulid Polychaetes (Ditrupa arietina) from the Pliocene of the Cope Basin, Murcia Region, Southeastern Spain

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    We report quantitative analyses of drilling predation on the free-living, tube-dwelling serpulid polychaete Ditrupa arietina from the Cope Cabo marine succession (Pliocene, Spain). Tubes of D. arietina are abundant in the sampled units: 9 bulk samples from 5 horizons yielded ∼5925 specimens of D. arietina. Except for fragmentation, tubes were well preserved. Complete specimens ranged from 3.1 to 13.4 mm in length and displayed allometric growth patterns, with larger specimens being relatively slimmer. Drilled Ditrupa tubes were observed in all samples. Drillholes, identified as Oichnus paraboloides, were characterized by circular to elliptical outline (drillhole eccentricity increased with its diameter), parabolic vertical profile, outer diameter larger than inner diameter, penetration of one tube wall only, narrow range of drill-hole sizes, and non-random (anterior) distribution of drillholes. A total of 233 drilled specimens were identified, with drilling frequencies varying across horizons from 2.7% to 21% (3.9% for pooled data). Many tube fragments were broken across a drillhole suggesting that the reported frequencies are conservative and that biologically-facilitated (drill-hole induced) fragmentation hampers fossil preservation of complete serpulid tubes. No failed or repaired holes were observed. Multiple complete drillholes were present (3.9%). Drilled specimens were significantly smaller than undrilled specimens and tube length and drill-hole diameter were weakly correlated. The results suggest that drillholes were produced by a size-selective, site-stereotypic predatory organism of unknown affinity. The qualitative and quantitative patterns reported here are mostly consistent with previous reports on recent and fossil Ditrupa and reveal parallels with drilling patterns documented for scaphopod mollusks, a group that is ecologically and morphologically similar to Ditrupa. Consistent with previous studies, the results suggest that free-dwelling serpulid polychaetes are preyed upon by drilling predators and may provide a viable source of data on biotic interactions in the fossil record
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