1,012 research outputs found

    Optimal Control Realizations of Lagrangian Systems with Symmetry

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    A new relation among a class of optimal control systems and Lagrangian systems with symmetry is discussed. It will be shown that a family of solutions of optimal control systems whose control equation are obtained by means of a group action are in correspondence with the solutions of a mechanical Lagrangian system with symmetry. This result also explains the equivalence of the class of Lagrangian systems with symmetry and optimal control problems discussed in \cite{Bl98}, \cite{Bl00}. The explicit realization of this correspondence is obtained by a judicious use of Clebsch variables and Lin constraints, a technique originally developed to provide simple realizations of Lagrangian systems with symmetry. It is noteworthy to point out that this correspondence exchanges the role of state and control variables for control systems with the configuration and Clebsch variables for the corresponding Lagrangian system. These results are illustrated with various simple applications

    A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU

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    Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).Our nearest neighbor, Proxima Centauri, hosts a temperate terrestrial planet. We detected in radial velocities evidence of a possible second planet with minimum mass m c sin i c = 5.8 ± 1.9 M ⊕ and orbital period P c = 5.21 - 0.22 + 0.26 years. The analysis of photometric data and spectro-scopic activity diagnostics does not explain the signal in terms of a stellar activity cycle, but follow-up is required in the coming years for confirming its planetary origin. We show that the existence of the planet can be ascertained, and its true mass can be determined with high accuracy, by combining Gaia astrometry and radial velocities. Proxima c could become a prime target for follow-up and characterization with next-generation direct imaging instrumentation due to the large maximum angular separation of ~1 arc second from the parent star. The candidate planet represents a challenge for the models of super-Earth formation and evolution.Peer reviewedFinal Published versio

    New compound sets identified from high throughput phenotypic screening against three kinetoplastid parasites:an open resource

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    Using whole-cell phenotypic assays, the GlaxoSmithKline high-throughput screening (HTS) diversity set of 1.8 million compounds was screened against the three kinetoplastids most relevant to human disease, i.e. Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei. Secondary confirmatory and orthogonal intracellular anti-parasiticidal assays were conducted, and the potential for non-specific cytotoxicity determined. Hit compounds were chemically clustered and triaged for desirable physicochemical properties. The hypothetical biological target space covered by these diversity sets was investigated through bioinformatics methodologies. Consequently, three anti-kinetoplastid chemical boxes of ~200 compounds each were assembled. Functional analyses of these compounds suggest a wide array of potential modes of action against kinetoplastid kinases, proteases and cytochromes as well as potential host–pathogen targets. This is the first published parallel high throughput screening of a pharma compound collection against kinetoplastids. The compound sets are provided as an open resource for future lead discovery programs, and to address important research questions.The support and funding of Tres Cantos Open Lab Foundation is gratefully acknowledgedPeer reviewe

    Improving drug discovery using a neural networks based parallel scoring function

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    Virtual Screening (VS) methods can considerably aid clinical research, predicting how ligands interact with drug targets. Most VS methods suppose a unique binding site for the target, but it has been demonstrated that diverse ligands interact with unrelated parts of the target and many VS methods do not take into account this relevant fact. This problem is circumvented by a novel VS methodology named BINDSURF that scans the whole protein surface to find new hotspots, where ligands might potentially interact with, and which is implemented in massively parallel Graphics Processing Units, allowing fast processing of large ligand databases. BINDSURF can thus be used in drug discovery, drug design, drug repurposing and therefore helps considerably in clinical research. However, the accuracy of most VS methods is constrained by limitations in the scoring function that describes biomolecular interactions, and even nowadays these uncertainties are not completely understood. In order to solve this problem, we propose a novel approach where neural networks are trained with databases of known active (drugs) and inactive compounds, and later used to improve VS predictions.This work has been jointly supported by the Fundación Séneca (Agencia Regional de Ciencia y Tecnología de la Región de Murcia) under grant 15290/PI/2010, by the Spanish MINECO and the European Commission FEDER funds under grants TIN2009-14475-C04 and TIN2012-31345, and by the Catholic University of Murcia (UCAM) under grant PMAFI/26/12. This work was partially supported by the computing facilities of Extremadura Research Centre for Advanced Technologies (CETA-CIEMAT), funded by the European Regional Development Fund (ERDF). CETA-CIEMAT belongs to CIEMAT and the Government of Spain

    Risk of Food Insecurity Reflects Health Status in Adult Relatives of PreK Children – ​ Data from the STEPS Snap-Ed Research Study​

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    Background: Past research shows a correlation between household food insecurity and chronic medical conditions such as diabetes in the general U.S. population as well as metabolic syndrome-related cardiometabolic markers in Hispanic/Latino youth. Furthermore, minority status, including Hispanic/Latino identity, shows an association with low food security and diabetes. The Hunger Vital Sign (HVS) is a validated screener designed to assess risk of food insecurity within households. This study analyzes associated factors related to the screener’s 2 questions, specifically targeting PreK 4-year-old children and their household relatives. The first question assesses concern about food running out before obtaining more due to financial constraints, while the second question evaluates instances when food did not last and there was insufficient money to purchase more. Methods: The participating preschools were primarily Hispanic/Latino and nested within schools and school districts. Data were collected through household questionnaires. The frequency of food insecurity (FI) risk was measured as an ordinal variable (never, sometimes, often) and dichotomized (never vs sometimes + often). Agreement between questions was assessed using the kappa coefficient. Mixed models were employed to predict the risk of children’s BMI and the risk of relatives developing chronic disease, adjusting for age and sex. Results: The study included 828 families, with 74% reporting never experiencing food insecurity, 22% sometimes, and 4% often. The agreement between the 2 survey questions was substantial (kappa 0.80, p \u3c 0.001). Probability of FI decreased as income level and education level of parents increased. No significant associations were found between FI and children’s age, BMI, height, or the ratio of children to adults in the household. However, a positive screen using the HVS correlated with hypertension and/or diabetes in the family. Conclusion: The HVS screens for food insecurity risk and is associated with health issues in adults rather than children\u27s body weight or height. Responses to the survey’s 2 questions can provide insights into the overall health status of a household, emphasizing the intricate relationship between food insecurity, malnutrition, and various health outcomes. The presented results support planning and resource allocation strategies to reduce food insecurity in the Hispanic/Latino population

    Metabolome and proteome changes in skeletal muscle and blood of pre-weaning calves fed leucine and threonine supplemented diets

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    In pre-weaning calves, both leucine and threonine play important roles in growth and muscle metabolism. In this study, metabolomics, proteomics and clinical chemistry were used to assess the effects of leucine and threonine supplementation added to milk replacer on 14 newborn Holstein male calves: 7 were fed a control diet (Ctrl) and 7 were fed the Ctrl diet supplemented with 0.3% leucine and 0.3% threonine (LT) from 5.6 days of age to 53.6 days. At this time, blood and semitendinosus muscle biopsies were collected for analysis. Integrated metabolomics and proteomics showed that branched-chain amino acids (BCAA) degradation and mitochondrial oxidative metabolism (citrate cycle and respiratory chain) were the main activated pathways in muscle because of the supplementation. BCAA derivatives and metabolites related to lipid mobilization showed the major changes. The deleterious effects of activated oxidative phosphorylation were balanced by the upregulation of antioxidant proteins. An increase in protein synthesis was indicated by elevated aminoacyl-tRNA biosynthesis and increased S6 ribosomal protein phosphorylation in skeletal muscle. In conclusion, LT group showed greater BCAA availability and mitochondrial oxidative activity; as the muscle cells undergo greater aerobic metabolism, antioxidant defenses were activated to compensate for possible cell damage. Data are available via ProteomeXchange (PXD016098)info:eu-repo/semantics/acceptedVersio

    A C60-aryne building block:synthesis of a hybrid all-carbon nanostructure

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    The synthesis of a [60]fullerene-benzyne building block and its further chemical cycloaddition reaction with graphene has resulted in a new all-carbon hybrid material which has been characterized by TGA, FTIR and Raman spectroscopies, XPS as well as TEM. Based on computational studies,the formation of both [2+2] and [4+2] cycloadducts on the graphene surface is feasible

    Final report : SIM comparison in mass standards SIM.M.M-K5

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    This report summarizes the results of a SIM comparison in masss carried out between 7 NMIs. Five mass standards with nominal values 2 kg, 200 g, 50 g, 1 g and 200 mg have been circulated by the NMIs. The results reported by the participants are consistent with each other and with the key comparison reference valu of the comparison CCM.M-K5 to which the present comparison has been linked.Fil: Becerra, L. O. Centro Nacional de Metrología (CENAM); MéxicoFil: Peña, L. M. Centro Nacional de Metrología (CENAM); MéxicoFil: Luján, L. Centro Nacional de Metrología (CENAM); MéxicoFil: Díaz, J. C. Centro Nacional de Metrología (CENAM); MéxicoFil: Centeno, , L. M. Centro Nacional de Metrología (CENAM); MéxicoFil: Loayza, V. M. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Cacais, F. A. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Ramos, O. Laboratorio Costarricense de Metrología (LaCoMet); Costa RicaFil: Rodriguez, S. Laboratorio Costarricense de Metrología (LaCoMet); Costa RicaFil: Garcia, F. Centro de Estudios, Medición y Certificación de Calidad (CESMEC); ChileFil: Leyton, F. Centro de Estudios, Medición y Certificación de Calidad (CESMEC); ChileFil: Santo, C. Laboratorio Tecnológico del Uruguay (LATU); UruguayFil: Caceres, J. Laboratorio Tecnológico del Uruguay (LATU); UruguayFil: Kornblit, F. Instituto Nacional de Tecnología Industrial (INTI); ArgentinaFil: Leiblich, J. Instituto Nacional de Tecnología Industrial (INTI); ArgentinaFil: Claude, J. National Research Council (NRC); Canad

    Final report : SIM comparison in mass standards SIM.M.M-K4

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    This report summarizes the results of a SIM comparison in masss carried out between 7 NMIs. Five mass standards with nominal values 2 kg, 200 g, 50 g, 1 g and 200 mg have been circulated by the NMIs. The results reported by the participants are consistent with each other and with the key comparison reference valu of the comparison CCM.M-K5 to which the present comparison has been linked.Fil: Becerra, L. O. Centro Nacional de Metrología (CENAM); MéxicoFil: Peña, L. M. Centro Nacional de Metrología (CENAM); MéxicoFil: Luján, L. Centro Nacional de Metrología (CENAM); MéxicoFil: Díaz, J. C. Centro Nacional de Metrología (CENAM); MéxicoFil: Centeno, , L. M. Centro Nacional de Metrología (CENAM); MéxicoFil: Loayza, V. M. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Cacais, F. A. Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMetro); BrasilFil: Ramos, O. Laboratorio Costarricense de Metrología (LaCoMet); Costa RicaFil: Rodriguez, S. Laboratorio Costarricense de Metrología (LaCoMet); Costa RicaFil: Garcia, F. Centro de Estudios, Medición y Certificación de Calidad (CESMEC); ChileFil: Leyton, F. Centro de Estudios, Medición y Certificación de Calidad (CESMEC); ChileFil: Santo, C. Laboratorio Tecnológico del Uruguay (LATU); UruguayFil: Caceres, J. Laboratorio Tecnológico del Uruguay (LATU); UruguayFil: Kornblit, F. Instituto Nacional de Tecnología Industrial (INTI); ArgentinaFil: Leiblich, J. Instituto Nacional de Tecnología Industrial (INTI); ArgentinaFil: Claude, J. National Research Council (NRC); Canad
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