1,794 research outputs found

    Kinetically Trapped Liquid-State Conformers of a Sodiated Model Peptide Observed in the Gas Phase

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    We investigate the peptide AcPheAla5LysH+, a model system for studying helix formation in the gas phase, in order to fully understand the forces that stabilize the helical structure. In particular, we address the question of whether the local fixation of the positive charge at the peptide's C-terminus is a prerequisite for forming helices by replacing the protonated C-terminal Lys residue by Ala and a sodium cation. The combination of gas-phase vibrational spectroscopy of cryogenically cooled ions with molecular simulations based on density-functional theory (DFT) allows for detailed structure elucidation. For sodiated AcPheAla6, we find globular rather than helical structures, as the mobile positive charge strongly interacts with the peptide backbone and disrupts secondary structure formation. Interestingly, the global minimum structure from simulation is not present in the experiment. We interpret that this is due to high barriers involved in re-arranging the peptide-cation interaction that ultimately result in kinetically trapped structures being observed in the experiment.Comment: 28 pages, 10 figure

    Syntactic vs. Semantic Locality: How Good Is a Cheap Approximation?

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    Extracting a subset of a given OWL ontology that captures all the ontology's knowledge about a specified set of terms is a well-understood task. This task can be based, for instance, on locality-based modules (LBMs). These come in two flavours, syntactic and semantic, and a syntactic LBM is known to contain the corresponding semantic LBM. For syntactic LBMs, polynomial extraction algorithms are known, implemented in the OWL API, and being used. In contrast, extracting semantic LBMs involves reasoning, which is intractable for OWL 2 DL, and these algorithms had not been implemented yet for expressive ontology languages. We present the first implementation of semantic LBMs and report on experiments that compare them with syntactic LBMs extracted from real-life ontologies. Our study reveals whether semantic LBMs are worth the additional extraction effort, compared with syntactic LBMs

    From data subjects to data suspects: challenging e-proctoring systems as a university practice

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    E-proctoring is a set of software and tools to monitor students’ behaviour during online examinations. Many universities have implemented this type of invigilation in response to the lockdowns during the pandemic to guarantee the validity and the integrity of exams. However, the intrusiveness of such technology into the students’ personal environment along with major accuracy problems (e.g., in authenticating black students) has attracted the scrutiny of various European data protection authorities and, more recently, equality bodies. In this paper, we critically approach the European normative framework available in countering the risks and situations of harms generated by e-proctoring through the lenses of data protection and anti-discrimination law. This work, in particular, is one of the first to systematise and analyse the corpus of online proctoring-related decisions that have emerged in the EU over the past three years. After an overview of the technical aspects of such technology and an outline of the legal issues debated in the literature, the paper will reconstruct and discuss the convergences and divergences in how courts and independent authorities have assessed the lawfulness of online invigilation tools. In our analysis, we observe that such instruments were evaluated differently depending on the concrete features implemented. However, with some notable exceptions, the General Data Protection Regulation and the anti-discrimination framework have largely proven helpful to combat the most intrusive forms of e-proctoring deployment or to mitigate their risks. Nevertheless, to ensure a safer and fairer educational environment, we conclude that a few crucial issues—including the effectiveness of the collective enforcement of rights, discriminatory effects for people not covered by a protected ground, and the governance of edTech within the university—should be further taken into account

    Devonian to Permian intrusions in the Zentralgneis Supersuite of the eastern Tauern Window constrained by U-Pb zircon geochronology and geochemistry

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    In the course of comprehensive geological mapping, the Geosphere Austria (formerly Geologische Bundesanstalt – Geological Survey of Austria) initiated a systematic geochemical and geochronological characterization of the metamorphic granitoids forming the Zentralgneis Supersuite in the eastern Tauern Window. Three dozens of samples from already defined units (Sonnblick, Siglitz, Romate, Göss, and Hochalm orthogneiss) as well as newly defined units (SĂ€uleck, Kampleck, and GrĂŒbelwand orthogneisses) were sampled in four different nappes of the Venediger Nappe-System (Sonnblick, Romate, Hochalm, and Göss nappe). Major and trace element geochemical analyses indicate three groups. Most of the Sonnblick orthogneiss samples, the Siglitz orthogneiss and other non-leucocratic orthogneisses derive from high-K, calc-alkaline granite with a peraluminous and magnesian composition. The analyzed samples classify as I-type (subordinately S-type) granites formed in volcanic arcs and show no negative Eu-anomaly. The Kampleck, SĂ€uleck, and GrĂŒbelwand orthogneiss as well as leucocratic orthogneisses derive from high-Si, calc-alkaline granite, aplite and pegmatite, with a peraluminous ferroan composition. This group classifies as S-type granites formed in a within-plate setting and samples show a clear negative Eu-anomaly as well as comparably low Ba and Sr concentrations. The Romate orthogneiss and one analyzed Sonnblick orthogneiss sample derive from shoshonitic, quartz-monzonite to syenite with metaluminous and magnesian composition. This group classifies as syn-collisional A-Type granites and shows no negative Eu-anomaly with comparably high Eu, U and Th concentrations. The three distinguished groups are found in different nappes of the Venediger Nappe System; however, note that single orthogneiss units can host elements of different characteristics. U-Pb zircon geochronology further constrains some of the orthogneiss units. A sample of coarse-grained Sonnblick orthogneiss with an augen microstructure yields a Late Devonian age. An atypical fine-grained Sonnblick orthogneiss with small K-feldspar yields a late Carboniferous age and a Siglitz orthogneiss sample yields an early Carboniferous age. Samples from Kampleck, SĂ€uleck and GrĂŒbelwand yield middle Permian ages. Our findings illustrate the complex and long lived intrusion story over 100 Myrs hidden in what is called the Zentralgneis Supersuite. The dominant group corresponding to I-type calc-alkaline plutonism contemporaneous to the Variscan Orogeny took more than 30 Myrs to form. At least in the Sonnblick orthogneiss, this group hosts younger intrusions that remain undefined and unmapped. Later Permian S-type intrusions are for the moment only attested in the Hochalm Nappe. However, based on lithological characteristics these can also be expected in other nappes (e.g. Sonnblick and Göss nappe). Finally, geochronological characterization of the Romate orthogneiss underpins any interpretation of its exotic chemistry. These results stress the importance of combined geochemical and geochronological analyses together with geological mapping for a more comprehensive understanding of the complex geological situation in the eastern Tauern Window

    The association between a body shape index and cardiovascular risk in overweight and obese children and adolescents

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    A Body Shape Index (ABSI) and normalized hip circumference (Hip Index, HI) have been recently shown to be strong risk factors for mortality and for cardiovascular disease in adults. We conducted an observational cross-sectional study to evaluate the relationship between ABSI, HI and cardiometabolic risk factors and obesity-related comorbidities in overweight and obese children and adolescents aged 2±18 years. We performed multivariate linear and logistic regression analyses with BMI, ABSI, and HI age and sex normalized z scores as predictors to examine the association with cardiometabolic risk markers (systolic and diastolic blood pressure, fasting glucose and insulin, total cholesterol and its components, transaminases, fat mass%detected by bioelectrical impedance analysis) and obesity- related conditions (including hepatic steatosis and metabolic syndrome). We recruited 217 patients (114 males), mean age 11.3 years. Multivariate linear regression showed a significant association of ABSI z score with 10 out of 15 risk markers expressed as continuous variables, while BMI z score showed a significant correlation with 9 and HI only with 1. In multivariate logistic regression to predict occurrence of obesity-related conditions and above-threshold values of risk factors, BMI z score was significantly correlated to 7 out of 12, ABSI to 5, and HI to 1. Overall, ABSI is an independent anthropometric index that was significantly associated with cardiometabolic risk markers in a pediatric population affected by overweight and obesity

    Disentangling influences of dyslexia, development, and reading experience on effective brain connectivity in children

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    Altered brain connectivity between regions of the reading network has been associated with reading difficulties. However, it remains unclear whether connectivity differences between children with dyslexia (DYS) and those with typical reading skills (TR) are specific to reading impairments or to reading experience. In this functional MRI study, 132 children (M = 10.06 y, SD = 1.46) performed a phonological lexical decision task. We aimed to disentangle (1) disorder-specific from (2) experience-related differences in effective connectivity and to (3) characterize the development of DYS and TR. We applied dynamic causal modeling to age-matched (ndys = 25, nTR = 35) and reading-level-matched (ndys = 25, nTR = 22) groups. Developmental effects were assessed in beginning and advanced readers (TR: nbeg = 48, nadv = 35, DYS: nbeg = 24, nadv = 25). We show that altered feedback connectivity between the inferior parietal lobule and the visual word form area (VWFA) during print processing can be specifically attributed to reading impairments, because these alterations were found in DYS compared to both the age-matched and reading-level-matched TR. In contrast, feedforward connectivity from the VWFA to parietal and frontal regions characterized experience in TR and increased with age and reading skill. These directed connectivity findings pinpoint disorder-specific and experience-dependent alterations in the brain's reading network. Keywords: Development; Developmental dyslexia; Dynamic causal modeling (DCM); Effective connectivity; Inferior parietal lobule; Reading network; Visual Word Forma Area (VWFA); fMRI

    Did the Great Recession affect sex ratios at birth for groups with a son preference?

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    This paper examines the extent to which the Great Recession affected gender composition at birth. We focus on ethnic minorities in the US known for a son preference—Chinese, Indians, and Koreans. Using the DID method, we find that in response to the Great Recession, the fraction of newborn boys increased among Chinese Americans. Our results suggest that a cultural norm, namely son preference, may be directly affected by economic conditions

    Effects of a multidisciplinary weight loss intervention in overweight and obese children and adolescents: 11 years of experience

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    Aims To evaluate the effects of an outpatient multidisciplinary weight loss intervention in reducing body mass index (BMI) in children and adolescents suffering overweight and obesity, changes in A Body Shape Index (ABSI, waist circumference normalized to height and weight) and Hip Index (HI, normalized hip circumference) during treatment and correlation between the ABSI and HI with change in BMI z score. Methods We analyze anthropometric data from pediatric patients affected by overweight and obesity aged 2 to 18 years old who entered our multidisciplinary weight loss intervention, which included medical, psychological and nutritional sessions, from January 1st 2006 to December 31st 2016. Lifestyle modification counselling was delivered. Follow-up visits were planned every month for 3 months and subsequently every 2±4 months. BMI, ABSI, and HI were converted to z scores using age and sex specific population normals. Results 864 patients entered our intervention. 453 patients (208 males), mean age 11.2 ±3.1 years, 392 with obesity (86%, z-BMI 2.90 ±0.80 SD) and 61 patients with overweight (z-BMI 1.73±0.21 SD) attended at least 1 follow-up visit. The mean number of visits was 3.5 (± 1.8 SD) in overweight subjects and 3.9 (±2.2 SD) in ones with obesity. At the last attended follow- up visit (at 16 ± 12 months SD) we observed a reduction in mean z-BMI in patients with obesity (to 2.52 ±0.71 SD) and patients with overweight (to 1.46 ±0.5 SD). Most patients (80.8%) reduced their BMI z scores. Mean ABSI and HI z scores showed no significant change. 78/392 patients (19.8%) recovered from obese to overweight, 5/392 (1.2%) from obese to normal weight. The recovery rate from overweight to normal weight was 13.1%. Ina multivariate model, initial BMI z score and number of follow-up visits were significant predictors of weight change, while age, sex, ABSI, and HI were not significant predictors. Conclusions Patients affected by overweight and obesity involved in a multidisciplinary weight loss intervention reduced their mean BMI z score, while ABSI and HI were stable. Weight loss was not predicted by initial ABSI or HI. More visits predict more weight loss, but dropout rates are high. The great majority of patients leave the weight management program before having normalized their BMI

    Fecal Microbiota Transplantation (FMT) as an Adjunctive Therapy for Depression-Case Report

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    Depression is a debilitating disorder, and at least one third of patients do not respond to therapy. Associations between gut microbiota and depression have been observed in recent years, opening novel treatment avenues. Here, we present the first two patients with major depressive disorder ever treated with fecal microbiota transplantation as add-on therapy. Both improved their depressive symptoms 4 weeks after the transplantation. Effects lasted up to 8 weeks in one patient. Gastrointestinal symptoms, constipation in particular, were reflected in microbiome changes and improved in one patient. This report suggests further FMT studies in depression could be worth pursuing and adds to awareness as well as safety assurance, both crucial in determining the potential of FMT in depression treatment
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