429 research outputs found

    From Stochastic Optics to the Wigner Formalism: The Role of the Vacuum Field in Optical Quantum Communication Experiments

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    The Wigner formalism in the Heisenberg picture constitutes a bridge that connects Quantum Optics to Stochastic Optics. The vacuum field appears explicitly in the formalism, and the wavelike aspects of light are emphasised. In addition, the zeropoint intensity as a threshold for detection is a common denominator in both theories. In this paper, after summarising the basic rules of the Wigner approach and its application to parametric down-conversion, some new results are presented that delve into the physical meaning of the zeropoint field in optical quantum communication. Specifically, the relationship between Bell-state distinguishability and the number of sets of zeropoint modes that take part in the experiment is analysed in terms of the coupling between the phases of the different fields involved and the subtraction of the zeropoint intensity at the detectors. Additionally, the connection between the compatibility theorem in quantum cryptography and zeropoint field is stressed

    Effects of Consumer‑Wearable Activity Tracker‑Based Programs on Objectively Measured Daily Physical Activity and Sedentary Behavior Among School‑Aged Children: A Systematic Review and Meta‑analysis

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    Carolina Casado-Robles is supported by a research grant from the Spanish Ministry of Universities [Grant Number: FPU16/03314]. This publication is part of the WearFit project (Reference B-SEJ-029-UGR18), funded by the FEDER/Regional Government of Andalusia-Ministry of Economy and Knowledge. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Background: The popularity of consumer-wearable activity trackers has led the scientific community to conduct an increasing number of intervention studies integrating them to promote physical activity (PA) and to reduce sedentary behavior (SB) levels among school-aged children. Therefore, the aim of the present study was to estimate the effects of consumer-wearable activity tracker-based programs on daily objectively measured PA and SB among apparently healthy school-aged children, as well as to compare the influence of participants’ and programs’ characteristics. Methods: Eligibility criteria were: (1) participants: apparently healthy school-aged children (< 18 years old); (2) intervention: aimed to promote PA and/or to reduce SB incorporating consumer-wearable activity trackers; (3) comparator: baseline measurements and/or a control/traditional group; (4) outcomes: objectively measured daily PA and/or SB levels; (5) study design: pre-experimental, quasi-experimental, and true-experimental trials. Relevant studies were searched from eight databases up to December 2020, as well as from four alternative modes of searching. Based on the Cochrane Risk-of-bias tool 2, the risk of bias was assessed following four domains: (1) randomization process; (2) missing outcome data; (3) measurement of the outcomes; and (4) selection of the reported results. Based on a comprehensive systematic review, meta-analyses of the Cohen’s standardized mean difference (d) and 95% confidence interval (CI) with a random-effects model were conducted to estimate the overall effects, as well as the within- and between-study subgroups analyses effects, of the programs on daily total steps, moderate-to-vigorous PA (MVPA), total PA and SB. Results: Forty-four publications (i.e., 45 studies) were included in the systematic review (5,620 unique participants; mean age = 12.85 ± 2.84 years) and 40 publications (i.e., 41 studies) in the meta-analysis. Programs had a mean length of 11.78 ± 13.17 weeks and most used a waist-worn consumer-wearable activity tracker (77.78% waist-worn; 22.22% wrist-worn). Programs characteristics were: goal-setting strategies (64.06%); participants’ logbooks (56.25%); counseling sessions (62.50%); reminders (28.13%); motivational strategies (42.19%); and exercise routine (17.19%). Results showed a statistically significant moderate favorable effect on daily total steps (d = 0.612, 95% CI 0.477–0.746), small favorable effect on daily MVPA (d = 0.220, 95% CI 0.134–0.307), trivial favorable effect on daily total PA (d = 0.151, 95% CI 0.038–0.264) and trivial unfavorable effect on daily SB (d = 0.172, 95% CI 0.039–0.305). Subgroups analyses showed a higher effect for daily total steps and daily MVPA levels in females and the physically inactive for daily total steps (p = 0.003–0.044). Programs with educational counseling and/or goal-setting strategies, as well as a greater number of strategies, were more effective for improving children’s daily total steps, and wrist-worn activity trackers were more effective than waist-worn trackers for improving their daily MVPA levels (p = 0.001–0.021). Conclusions: Consumer-wearable activity tracker-based programs seem to be effective in promoting school-aged children’s daily total steps and MVPA levels, especially for females and those that are physically inactive. These programs should include specific goal-setting, educational counseling, and wrist-worn trackers as especially effective strategies. However, due to the certainty of evidence being from “low” to “moderate”, future well-designed primary research studies about the topic are needed.Spanish Government FPU16/03314FEDER/Regional Government of Andalusia-Ministry of Economy and Knowledge B-SEJ-029-UGR1

    Estudio de la ventilación en quirófanos y habitaciones de aislados infecciosos

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    La transmisión aérea de infecciones es un problema en edificios donde varias personas comparten un mismo espacio. La ventilación juega un papel en la transmisión aérea de ciertas infecciones. En hospitales, este problema es relevante, porque conviven en un mismo recinto personas infectadas, personas con un sistema inmune deprimido y personal que trabaja a diario. Dos estudios experimentales validan el modelo numérico para dos tipos de ventilación tratados en este trabajo. Un primer estudio experimental mide el campo de velocidades en un modelo de quirófano unidireccional mediante la técnica PIV. Un segundo ensayo mide el campo de velocidades próximo a un difusor rotacional utilizando anemometría por ultrasonidos. El objetivo final de este trabajo es establecer una metodología que evalúe la calidad de la ventilación de cualquier configuración de quirófano y habitación de aislados infecciosos y que permita extrapolarla a otros recintos. ValladolidDepartamento de Ingeniería Energética y Fluidomecánic

    A rare missense mutation in a type 2 diabetes patient decreases the transcriptional activity of human sterol regulatory element binding protein-1

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    11 pages, 3figures, 1 table.-PMID: 16429400 [PubMed]Sterol regulatory element binding protein 1 (SREBP-1) transcription factors play a key role in energy homeostasis by regulating genes involved in both carbohydrate and lipid metabolism, and in adipocyte differentiation. The 5' end of the mRNA-encoding SREBP-1 exists in two forms, designated 1a and 1c. The divergence results from the use of two transcription start sites that produce two separate 5' exons, each of which is spliced to a common exon 2. Mutations in the sterol regulatory element binding protein gene (SREBF)-1 may contribute to insulin resistance states. However, the variants described to date do not affect the SREBP function. In this study, we investigated the functional consequences of a novel missense mutation common to both SREBP-1 isoforms identified in a Spanish Type 2 diabetic patient (c.677C>T, SREBP-1a p.T226M; c.605C>T, SREBP-1c p.T202M). Using reporter gene analysis and electrophoretic mobility shift assays, we found that this variant impaires the transcriptional activity and reduces DNA binding ability despite its comparable protein stability to the wild-type SREBP-1. This decreased activity impaires the expression of known downstream targets, such as the LDL receptor and fatty acid synthase genes. Our findings suggest that the threonine residue and/or surrounding region play an important role in the SREBP-1 functionThis study was supported by grants from Instituto de Salud Carlos III, Red de Centros (RCMN) C03/08, and from Ministerio de Educación y Ciencia (SAF2003-01262). S.V. is supported by a fellowship from Consejo Superior de Investigaciones Científicas I3P-BPD2001-1.Peer reviewe

    Evolution of research about physical activity in the natural environment in physical education: Results in Web of ScienceTM from 1990 to 2016

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    Monográfico con el título: "Actividades Físicas en el Medio Natural (1ª parte)"Resumen basado en el de la publicaciónTítulo, resumen y palabras clave también en inglésSe pretende analizar la evolución del número de publicaciones sobre actividad física en el medio natural en educación física. Para ello, se realizó una búsqueda bibliográfica en la base de datos Web of ScienceTM desde 1990 hasta 2016. Los términos de búsqueda usados se basaron en dos conceptos: 1) actividad física en el medio natural y 2) educación física. Se encontraron un total de 116 resultados, con una media de 4,3 publicaciones por año, observándose una tendencia a aumentar el número de publicaciones a lo largo de los años, especialmente desde 2011 hasta la actualidad. En cambio, del total de estudios sobre educación física desde 1990 hasta 2016, solo el 5% trataron sobre actividades en el medio natural, con una media de 0,2% de publicaciones por año. En general, se observó una cantidad relativa de publicaciones muy similar desde 1990 hasta 2016. Se concluye afirmando que se produce un aumento absoluto significativo en la producción de publicaciones sobre actividad física en el medio natural en educación física, especialmente desde 2011. En cambio, si se tiene en cuenta la evolución relativa a la investigación sobre la educación física, la producción científica sobre el contenido de medio natural se mantiene estable.ES

    Could an intermittent Physical Education-based fitness teaching unit affect secondary school students’ motivation, autotelic experience, and physical self-concept? A cluster-randomized controlled trial

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    The authors want to thank you to all the students and the Physical Education teachers who made this research possible. We also thank Aliisa Hatten for the English revision of the manuscript. Santiago Guijarro-Romero and Carolina Casado-Robles are supported by a research grant from the Spanish Ministry of Universities [grant number: FPU15/02387 and FPU16/03314, respectively].Objective: The purpose of the present study was to compare the effects of traditional and intermittent physical fitness-based teaching units on secondary school students’ motivation toward Physical Education, autotelic experience, and physical self-concept. Methods: Six classes [126 students (57.9% females) aged 13-15 years], balanced by grade, were cluster-randomly assigned into control (n = 40), traditional (n = 34) and innovative (n = 52) groups. The traditional group performed a physical fitness teaching unit twice a week for nine weeks (35-40 minutes of the main part of each session). The innovative group worked during the first half of the sessions’ main part (18-20 minutes) similarly to the traditional group, and during the second half they worked on invasion sports. Before and after the intervention, students’ motivation toward Physical Education and physical self-concept were measured through the Perceived Locus of Causality-II Scale and the short form of the Physical Self Description Questionnaire. Results: The Multilevel Linear Model showed that the control group students decreased statistically significantly in the integrated, introjected, and controlled motivation compared to those from the innovative and traditional groups (p 0.05). Conclusion: Regardless of the teaching unit structure applied (i.e., traditional or intermittent), it could be necessary that Physical Education teachers apply specific strategies for improving these psychological variables of the students.Spanish Ministry of Universities FPU15/02387Spanish Ministry of Universities FPU16/0331
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