7,625 research outputs found
Three-Dimensional Wave Packet Approach for the Quantum Transport of Atoms through Nanoporous Membranes
Quantum phenomena are relevant to the transport of light atoms and molecules
through nanoporous two-dimensional (2D) membranes. Indeed, confinement provided
by (sub-)nanometer pores enhances quantum effects such as tunneling and zero
point energy (ZPE), even leading to quantum sieving of different isotopes of a
given element. However, these features are not always taken into account in
approaches where classical theories or approximate quantum models are
preferred. In this work we present an exact three-dimensional wave packet
propagation treatment for simulating the passage of atoms through periodic 2D
membranes. Calculations are reported for the transmission of He and He
through graphdiyne as well as through a holey graphene model. For
He-graphdiyne, estimations based on tunneling-corrected transition state theory
are correct: both tunneling and ZPE effects are very important but competition
between each other leads to a moderately small He/He selectivity. Thus,
formulations that neglect one or another quantum effect are inappropriate. For
the transport of He isotopes through leaky graphene, the computed transmission
probabilities are highly structured suggesting widespread selective adsorption
resonances and the resulting rate coefficients and selectivity ratios are not
in agreement with predictions from transition state theory. Present approach
serves as a benchmark for studies of the range of validity of more approximate
methods.Comment: 4 figure
Sarcopenic osteoporosis, sarcopenic obesity, and sarcopenic osteoporotic obesity in the Camargo cohort (Cantabria, Spain)
Summary
The associations of sarcopenia with osteoporosis or obesity have a very low prevalence. No trend towards an association between osteoporosis and sarcopenia is observed. Sarcopenia and obesity tend not to coincide, as if they were antagonistic disorders.
Purpose
To know (a) the prevalence in our region of sarcopenic osteoporosis (association of sarcopenia and osteoporosis (T-score<2.5)), sarcopenic obesity, and the association of osteoporosis, sarcopenia, and obesity; (b) the tendency of osteoporosis, sarcopenia, and obesity to associate with each other; and (c) the bone mineral density (BMD), the components of sarcopenia, and the prevalence of fragility fractures in these associations.
Methods
The study was performed in the Camargo cohort. Osteoporosis was diagnosed by DXA, sarcopenia by the EWGSOP-1 criteria, and obesity by body mass index (BMI) and fat percentage. Fractures were verified radiographically or by consulting the medical records.
Results
The prevalence of sarcopenic osteoporosis was 2.8% and the OR for this association 1.03 (p=0.89). The prevalence of sarcopenic obesity by BMI was 1.4% and by fat percentage 5.9% (corresponding ORs: 0.18 (p<0.0001) and 0.58 (p<0.003) respectively). The prevalence of the association of osteoporosis, sarcopenia, and obesity was 0.0% when assessed by BMI and 0.8% when assessed by fat percentage. Patients with sarcopenic osteoporosis have less muscle mass and more fragility fractures than sarcopenic patients overall. In patients with sarcopenic obesity by fat percentage, muscle mass and strength, as well as physical performance, were similar to those of sarcopenic patients overall. Neither BMD nor fracture prevalence showed differences between patients with sarcopenic obesity and patients with sarcopenia or obesity in general.
Conclusion
Our study supports the idea that the prevalence of the mixed disorders studied is low. No significant association between osteoporosis and sarcopenia was found. Sarcopenia and obesity seem to tend to occur in different people, as if suffering from one of them hinders suffering from the other.Funding: Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This study was funded by grants from
the Instituto de Salud Carlos III (PI18/00762), Ministerio de Economía y Competitividad, Spain, which included FEDER funds from the EU
Spatial spillovers in public expenditure on a municipal level in Spain
A key function of local governments is to provide a wide array of public services. The supply of these services has been found to create spatial spillovers among neighbouring municipalities. Although it is generally agreed that spillovers are present in models that explain government expenditures, their type—whether endogenous, exogenous or residual—and sign—whether positive or negative—remain ambiguous. In most cases, a subjective process is used to select the type of spatial regression model used in analysis, with mixed results. Per capita expenditures of ten subprogrammes (Security, Housing, Welfare, Environment, Social services, Employment promotion, Health, Education, Culture and Sport) are analysed for all Spanish municipalities with more than 5000 inhabitants in the 2010–2012 period. A Spatial Seemingly Unrelated Regression methodology in a panel framework is used to incorporate correlation between different subprogrammes and spatial dependence. Our results show that the three types of spatial effects are present. Furthermore, substantive dependence is positive in most cases, while negative residual dependence is observed in some.We gratefully acknowledge the contribution of three anonymous reviewers in helping us improve the quality of this paper. Prof. Fernando A. López , grateful for the financial support offered by the projects from Programa de Ayudas a Grupos de Excelencia de la Región de Murcia, Fundación Seneca (#19884-GERM-15) and Ministry of Economy and Competiveness (ECO2015-651758)
Fracturación y control tectosedimentario neógeno en el borde sureste de la Cuenca de Lorca
En este trabajo se estudia el control tectosedimentario ejercido por la fracturación neógena en la sedimentación en el borde suroriental de la Cuenca de Larca. El control más importante está impuesto por la actividad del Corredor Tectónico de la Falla de Alhama de Murcia. Este corredor controló la formación del borde sur de la citada cuenca a través de movimientos de carácter normal que activaron el inicio del depósito mioceno. Durante el Tortoniense y el Messiniense la cinemática sinestral e inversa del corredor controla la formación del anticlinal que estructura la Sierra de La Tercia y provoca reactivaciones de procesos erosivos en áreas emergidas
Predictive analysis of transmissible quinolone resistance indicates Stenotrophomonas maltophilia as a potential source of a novel family of Qnr determinants
Additional files: Microsoft excel document containing the descriptions of the genes shown in Figure 2.Background
Predicting antibiotic resistance before it emerges at clinical settings constitutes a novel approach for preventing and fighting resistance of bacterial pathogens. To analyse the possibility that novel plasmid-encoded quinolone resistance determinants (Qnr) can emerge and disseminate among bacterial pathogens, we searched the presence of those elements in nearly 1000 bacterial genomes and metagenomes.
Results
We have found a number of novel potential qnr genes in the chromosomes of aquatic bacteria and in metagenomes from marine organisms. Functional studies of the Stenotrophomonas maltophilia Smqnr gene show that plasmid-encoded SmQnr confers quinolone resistance upon its expression in a heterologous host.
Conclusion
Altogether, the data presented in our work support the notion that predictive studies on antibiotic resistance are feasible, using currently available information on bacterial genomes and with the aid of bioinformatic and functional tools. Our results confirm that aquatic bacteria can be the origin of plasmid-encoded Qnr, and highlight the potential role of S. maltophilia as a source of novel Qnr determinants.This work has been supported by grants BIO2005-04278, LSHM-CT-2005-518152 and LSHM-CT-2005-018705. L. M-M and J.M. R.-M. are supported by REIPI, RD06/0008 from ISCIII, Ministerio de Sanidad y Consumo, Spain.Peer reviewe
Identificación Partidaria versus Personalización de las campañas electorales en México: el caso del Distrito II en las elecciones de 2006 y 2009 en el Estado de México
El propósito de esta investigación es analizar la personalización de la política frente a la identificación partidaria, siendo esta última la que en principio ha prevalecido en la vida política del país durante 71 años, desde 1929, cuando se fundó el Partido Nacional Revolucionario, hasta el año 2000, cuando el Partido Revolucionario Institucional perdió por primera vez una elección presidencial
Dual Indicators to Analyse AI Benchmarks: Difficulty, Discrimination, Ability and Generality
[EN] With the purpose of better analyzing the result of artificial intelligence (AI) benchmarks, we present two indicators on the side of the AI problems, difficulty and discrimination, and two indicators on the side of the AI systems, ability and generality. The first three are adapted from psychometric models in item response theory (IRT), whereas generality is defined as a new metric that evaluates whether an agent is consistently good at easy problems and bad at difficult ones. We illustrate how these key indicators give us more insight on the results of two popular benchmarks in AI, the Arcade Learning Environment (Atari 2600 games) and the General Video Game AI competition, and we include some guidelines to estimate and interpret these indicators for other AI benchmarks and competitions.This work was supported by the U.S. Air Force Office of Scientific Research under Award FA9550-17-1-0287; in part by the EU (FEDER) and the Spanish MINECO under Grant TIN 2015-69175-C4-1-R; and in part by the Generalitat Valenciana PROMETEOII/2015/013. The work of F. Mart ' inez-Plumed was supported by INCIBE (Ayudas para la excelencia de los equipos de investigaci ' on avanzada en ciberseguridad), the European Commission, JRC's Centre for Advanced Studies, HUMAINT project (Expert Contract CT-EX2018D335821-101), and UPV PAID-06-18 Ref. SP20180210. The work of J. Hern ' andez-Orallo was supported in part by Salvador de Madariaga grant (PRX17/00467) from the Spanish MECD, in part by the BEST Grant (BEST/2017/045) from the GVA for research stays at the CFI, and in part by the FLI grant RFP2-152.Martínez-Plumed, F.; Hernández-Orallo, J. (2020). Dual Indicators to Analyse AI Benchmarks: Difficulty, Discrimination, Ability and Generality. IEEE Transactions on Games. 12(2):121-131. https://doi.org/10.1109/TG.2018.2883773S12113112
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