1,307 research outputs found

    Fast Approximate Geodesics for Deep Generative Models

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    The length of the geodesic between two data points along a Riemannian manifold, induced by a deep generative model, yields a principled measure of similarity. Current approaches are limited to low-dimensional latent spaces, due to the computational complexity of solving a non-convex optimisation problem. We propose finding shortest paths in a finite graph of samples from the aggregate approximate posterior, that can be solved exactly, at greatly reduced runtime, and without a notable loss in quality. Our approach, therefore, is hence applicable to high-dimensional problems, e.g., in the visual domain. We validate our approach empirically on a series of experiments using variational autoencoders applied to image data, including the Chair, FashionMNIST, and human movement data sets.Comment: 28th International Conference on Artificial Neural Networks, 201

    Time-position characterization of conflicts: a case study of collaborative editing

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    International audienceCollaborative editing (CE) became increasingly common, often compulsory in academia and industry where people work in teams and are distributed across space and time. We aim to study collabora-tive editing behavior in terms of collaboration patterns users adopt and in terms of a characterisation of conflicts, i.e. edits from different users that occur close in time and position in the document. The process of a CE can be split into several editing 'sessions' which are performed by a single author ('single-authored session') or several authors ('co-authored session'). This fragmentation process requires a pre-defined 'maximum time gap' between sessions which is not yet well defined in previous studies. In this study, we analysed CE logs of 108 collaboratively edited documents. We show how to establish a suitable 'maximum time gap' to split CE activities into sessions by evaluating the distribution of the time distance between two adjacent sessions. We studied editing activities inside each 'co-author session' in order to define potential conflicts in terms of time and position dimensions before they occur in the document. We also analysed how many of these potential conflicts become real conflicts. Findings show that potential conflicting cases are few. However, they are more likely to become real conflicts

    Identification of a Novel ZIC3 Isoform and Mutation Screening in Patients with Heterotaxy and Congenital Heart Disease

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    Patients with heterotaxy have characteristic cardiovascular malformations, abnormal arrangement of their visceral organs, and midline patterning defects that result from abnormal left-right patterning during embryogenesis. Loss of function of the transcription factor ZIC3 causes X-linked heterotaxy and isolated congenital heart malformations and represents one of the few known monogenic causes of congenital heart disease. The birth incidence of heterotaxy-spectrum malformations is significantly higher in males, but our previous work indicated that mutations within ZIC3 did not account for the male over-representation. Therefore, cross species comparative sequence alignment was used to identify a putative novel fourth exon, and the existence of a novel alternatively spliced transcript was confirmed by amplification from murine embryonic RNA and subsequent sequencing. This transcript, termed Zic3-B, encompasses exons 1, 2, and 4 whereas Zic3-A encompasses exons 1, 2, and 3. The resulting protein isoforms are 466 and 456 amino acid residues respectively, sharing the first 407 residues. Importantly, the last two amino acids in the fifth zinc finger DNA binding domain are altered in the Zic3-B isoform, indicating a potential functional difference that was further evaluated by expression, subcellular localization, and transactivation analyses. The temporo-spatial expression pattern of Zic3-B overlaps with Zic3-A in vivo, and both isoforms are localized to the nucleus in vitro. Both isoforms can transcriptionally activate a Gli binding site reporter, but only ZIC3-A synergistically activates upon co-transfection with Gli3, suggesting that the isoforms are functionally distinct. Screening 109 familial and sporadic male heterotaxy cases did not identify pathogenic mutations in the newly identified fourth exon and larger studies are necessary to establish the importance of the novel isoform in human disease

    Cloning, expression and characterization of l-asparaginase from Withania somnifera L. for large scale production

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    l-Asparaginase (E.C. 3.5.1.1) is used as a therapeutic agent in the treatment of acute childhood lymphoblastic leukemia. It is found in a variety of organisms such as microbes, plants and mammals. In plants, l-asparaginase enzymes are required to catalyze the release of ammonia from asparagine, which is the main nitrogen-relocation molecule in these organisms. An Indian medicinal plant, Withania somnifera was reported as a novel source of l-asparaginase. l-Asparaginase from W. somnifera was cloned and overexpressed in E. coli. The enzymatic properties of the recombinant enzyme were investigated and the kinetic parameters (Km, kcat) for a number of substrates were determined. The kinetic parameters of selected substrates were determined at various pH and the pH- and temperature-dependence profiles were analyzed. WA gene successfully cloned into E. coli BL21 (DE3) showed high asparaginase activity with a specific activity of 17.3 IU/mg protein

    Overweight and lifestyle behaviors of low socioeconomic elementary school children in Buenos Aires

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    <p>Abstract</p> <p>Background</p> <p>There is growing interest in understanding the role that lifestyle behaviors play in relation to children's weight status. The objective of the study was to determine the association between children s BMI and dietary practices and maternal BMI.</p> <p>Methods</p> <p>330 students (168M) aged 8.9 + 2 y from 4 suburban Buenos Aires elementary schools, and their mothers aged 36.2 + 7 y were examined between April and September 2007. Mothers were asked about their children s lifestyle. Data included parental education levels socioeconomic status, mothers and children s BMI, and Tanner stage.</p> <p>Results</p> <p>All families were in the low socio-economic class. 79% of parents had an elementary education or less. 61 (18.5%) of children were obese (OB) (BMI>95%ile per CDC norms), and 53 (16.1%) overweight (OW) (BMI>85<95%ile). 103 (31.2%) of mothers were OB (BMI>30 kg/m2), and102 (30.9%) OW (BMI>25<30). 63% the children were pre-pubertal. 40% had a TV set in their bedroom. 13% of the children skipped breakfast and only 38% watched TV ≤2 hours daily, as recommended. Multiple logistic regression analysis showed a positive association between children s OW/OB and drinking sweetened beverages (OR = 1.24; 95% CI, 1.02–1.52), TV viewing (OR = 1.30; 95% CI,1.05–1.62), and maternal BMI (OR: 1.07; 95% CI,1.02–1.12), and a negative association with eating breakfast (OR = 0.43; 95% CI, 0.19–0.97) adjusted for fruit and vegetables consumption, milk consumption, maternal educational level and socioeconomic class.</p> <p>Conclusion</p> <p>Our results suggest that TV viewing, drinking sweet beverages, skipping breakfast, and maternal BMI are important predictive variables for childhood OW/OB.</p

    Depurated fish as an alternative reference for field-based biomarker monitoring

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    The whole of the Swan-Canning Estuary, in the south-west of Australia, is impacted by human activity, and the selection of a local reference site to assess the impact of environmental contamination on the health of biota is not possible. To determine whether fish depurated under laboratory conditions could be used as an alternative to a reference site; adult black bream (Acanthopagrus butcheri) were collected from the estuary and maintained in clean water (S24) for 3 months. A suite of biomarkers of fish health were assessed, and the results were compared with field-captured black bream from three sites within the estuary (Ascot, Claisebrook, and Riverton). Comparisons of a subset of biomarkers were also made between hatchery-bred juvenile fish and the depurated fish. Biomarker levels were up to 3.8 times higher in field captured fish compared with depurated fish, while DNA integrity was lower. EROD activity was comparable in the hatchery-bred black bream to the depurated fish while s-SDH levels were two times higher in the hatchery fish. From the results obtained, field-captured black bream depurated for 3 months are suitable to determine reference/baseline levels for biomarker of health studies in estuarine environments

    Measured body mass index, body weight perception, dissatisfaction and control practices in urban, low-income African American adolescents

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    <p>Abstract</p> <p>Background</p> <p>Current understanding of the associations between actual body weight status, weight perception, body dissatisfaction, and weight control practices among low-income urban African American adolescents is limited. The knowledge can help direct future intervention efforts.</p> <p>Methods</p> <p>Cross-sectional data including measured weight and height and self-reported weight status collected from 448 adolescents in four Chicago Public Schools were used.</p> <p>Results</p> <p>The prevalence of overweight and obesity (BMI ≥ 85<sup>th </sup>percentile) was 39.8%, but only 27.2% considered themselves as obese, although 43.4% reported trying to lose weight. Girls were more likely to express weight dissatisfaction than boys, especially those with BMI ≥ 95<sup>th </sup>percentile (62.9% vs. 25.9%). BMI ≥ 85<sup>th </sup>percentile girls were more likely to try to lose weight than boys (84.6% vs. 66.7%). Among all adolescents, 27.2% underestimated and 67.2% correctly judged their own weight status. Multinomial logistic models show that those with BMI ≥ 85<sup>th </sup>percentile, self-perceived as obese, or expressed body dissatisfaction were more likely to try to lose weight; adjusted odds ratios and 95% confidence intervals were 4.52 (2.53–8.08), 18.04 (7.19–45.30), 4.12 (1.64–10.37), respectively. No significant differences were found in diet and physical activity between those trying to lose weight and those not trying, but boys who reported trying to lose weight still spent more television time (P < 0.05).</p> <p>Conclusion</p> <p>Gender differences in weight perception, body dissatisfaction, and weight control practices exist among African American adolescents. One-third did not appropriately classify their weight status. Weight perception and body dissatisfaction are correlates of weight control practices. Adolescents attempting to lose weight need be empowered to make adequate desirable behavioral changes.</p

    SLO-2 Is Cytoprotective and Contributes to Mitochondrial Potassium Transport

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    Mitochondrial potassium channels are important mediators of cell protection against stress. The mitochondrial large-conductance “big” K+ channel (mBK) mediates the evolutionarily-conserved process of anesthetic preconditioning (APC), wherein exposure to volatile anesthetics initiates protection against ischemic injury. Despite the role of the mBK in cardioprotection, the molecular identity of the channel remains unknown. We investigated the attributes of the mBK using C. elegans and mouse genetic models coupled with measurements of mitochondrial K+ transport and APC. The canonical Ca2+-activated BK (or “maxi-K”) channel SLO1 was dispensable for both mitochondrial K+ transport and APC in both organisms. Instead, we found that the related but physiologically-distinct K+ channel SLO2 was required, and that SLO2-dependent mitochondrial K+ transport was triggered directly by volatile anesthetics. In addition, a SLO2 channel activator mimicked the protective effects of volatile anesthetics. These findings suggest that SLO2 contributes to protection from hypoxic injury by increasing the permeability of the mitochondrial inner membrane to K+
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