1,029 research outputs found

    Spontaneous symmetry breaking as a resource for noncritically squeezed light

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    In the last years we have proposed the use of the mechanism of spontaneous symmetry breaking with the purpose of generating perfect quadrature squeezing. Here we review previous work dealing with spatial (translational and rotational) symmetries, both on optical parametric oscillators and four-wave mixing cavities, as well as present new results. We then extend the phenomenon to the polarization state of the signal field, hence introducing spontaneous polarization symmetry breaking. Finally we propose a Jaynes-Cummings model in which the phenomenon can be investigated at the single-photon-pair level in a non-dissipative case, with the purpose of understanding it from a most fundamental point of view.Comment: Review for the proceedings of SPIE Photonics Europe. 11 pages, 5 figures

    Algebraic Properties of Qualitative Spatio-Temporal Calculi

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    Qualitative spatial and temporal reasoning is based on so-called qualitative calculi. Algebraic properties of these calculi have several implications on reasoning algorithms. But what exactly is a qualitative calculus? And to which extent do the qualitative calculi proposed meet these demands? The literature provides various answers to the first question but only few facts about the second. In this paper we identify the minimal requirements to binary spatio-temporal calculi and we discuss the relevance of the according axioms for representation and reasoning. We also analyze existing qualitative calculi and provide a classification involving different notions of a relation algebra.Comment: COSIT 2013 paper including supplementary materia

    Detección de puntos calientes para la predicción de averías en las zonas de estudio I y II de la CNEL – EP, UNIDAD DE NEGOCIOS MANABI

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    Abstract: This paper deals with the detection of PC that is presented in the lines of M / T nearshore for which the study is conducted in San Clemente and Crucita to 13.8 Kv feeders, which is determined as area I study, this study describes how to detect the existence of PC in the different elements of the structures forming the said power lines (zona study I). And in this other area are in populated areas and abundant pollution for which the study  is conducted in the feeders 3 (Portoviejo Centro) and 4 (Shopping-. Cdla Los Tamarindos) to 13.8 KV, which is determined as an area of study II. This study describes how to detect the existence of P.C in the different elements of the structures forming the said power lines. Once the current state of the lines is described, it proceeds to determine the possible presence of P.C in each of the elements of the structures. In addition, statistical analysis will determine the items that need maintenance either preventive, predictive or corrective measures in order to implement measures that help to maintain proper lines  M /  T, and to  provide better quality  of electric service, and not have to regret lost electric power by joule effects shots in lines due to PC.  Index Terms: maintenance, preventive measures, predictive measures, corrective measures, power lines

    EVALUACIÓN DE LAS COMPETENCIAS COGNITIVAS Y SOCIALES DE NIÑOS QUE HAN ESTADO EN SITUACIÓN DE CALLE

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    The following study is an exploratory approach to the population of street children of Montevideo. It involves 27 children of both sexes between 7 and 13 years. Sociodemographic variables were considered and it was evaluated the neuropsychological development, including the use of oral language, the relationship with the writing code, logical-mathematical reasoning skills, cognitive functioning and exploring some psychopathological indicators. The results show that this is a population with high levels of weaknesses and vulnerabilities, and a significant presence of behavioral disorders. In the cognitive aspect, there is some level of effectiveness in the implementation of intellectual nonverbal operations. In the verbal tasks, significant deficits for the low overall development of language were found. This would have a negative impact on school integration as well as on the capacity for self-regulation of behavior.En el siguiente estudio se busca una aproximación exploratoria a la población de los niños y niñas en situación de calle de Montevideo. Se trabajo con 27 niños de ambos sexos de entre 7 y 13 años. Se consideraron las variables sociodemográficas y se evaluó el desarrollo neuropsicológico, incluyendo la utilización del lenguaje oral, la relación con el código escrito, las habilidades de razonamiento lógico-matemático, el funcionamiento cognitivo general y la exploración de algunos indicadores psicopatológicos. Los resultados muestran que se trata de una población con un alto nivel de carencias y vulnerabilidades, y una importante presencia de trastornos comportamentales. En el aspecto cognitivo, se encuentra algún nivel de efectividad en la ejecución intelectual de operaciones no verbales. En las  tareas verbales, se comprobaría un déficit significativo por el escaso desarrollo general del lenguaje. Esto tendría consecuencias negativas en la inserción escolar así como en la capacidad de auto-regulación del comportamiento

    Description of the first-stage juveniles of Xiphinema cretense and X. herakliense - Distribution of Xiphinema and Longidorus species in olive orchards and grapevines in Crete, Greece

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    The occurrence of nematodes of the family Longidoridae was investigated in soil samples collected from cultivated and wild olives and grapevines in Crete. The first-stage juveniles of Xiphinema cretense and X. herakliense are described for the first time. The species X. israeliae, X. cretense, X. herakliense and Longidorus pseudoelongatus, previously recorded exclusively from olives in Crete, are herein reported in the rhizosphere of grapevines. Also L. iranicus is reported for the first time in cultivated olive, while X. italiae and L. closelongatus are reported for the first time in wild olive in Crete. Data on the occurrence of phytoparasitic nematode species in cultivated olives, wild olives and grapevines are updated with those previously published.This research was supported by grant KBBE 219262 ArimNET-ERANET FP7 2012-2015 Project PESTOLIVE ‘Contribution of olive history for the management of soilborne parasites in the Mediterranean basin’ from Hellenic Agricultural Organization-DEMETER and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), grant AGR-136 from ‘Consejería de Economía, Innvovación y Ciencia’ from Junta de Andalucía, and Union Europea, Fondo Europeo de Desarrollo regional, “Una manera de hacer Europa”. I.G. Birmpilis and E. Nasiou were employed by the ARIMNET-PESTOL-IVE project.Peer reviewe

    Quantum coherent control of highly multipartite continuous-variable entangled states by tailoring parametric interactions

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    The generation of continuous-variable multipartite entangled states is important for several protocols of quantum information processing and communication, such as one-way quantum computation or controlled dense coding. In this article we theoretically show that multimode optical parametric oscillators can produce a great variety of such states by an appropriate control of the parametric interaction, what we accomplish by tailoring either the spatio-temporal shape of the pump, or the geometry of the nonlinear medium. Specific examples involving currently available optical parametric oscillators are given, hence showing that our ideas are within reach of present technology.Comment: 14 pages, 5 figure

    Effects of multicomponent training and detraining on the fitness of older adults with or at risk of frailty: results of a 10-month quasi-experimental study

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    The aims of this study were (1) to analyse the effects of a 6-month multicomponent training (MCT) on the physical fitness of older adults with or at risk of frailty; (2) to study the consequences of a 4-month detraining period; (3) to analyse the influence of frailty status on the training and detraining adaptations. A total of 102 robust, frail and prefrail older adults (80.1 ± 6.1 y) were divided into an intervention (TRAIN) and control group (CON). The TRAIN performed a 6-month MCT, while the CON continued with their usual lifestyle. Fitness assessment was mainly based on the Senior Fitness Test. Four evaluations were carried out; at baseline, and at 3, 6 and 10 months from baseline. Linear mixed models were performed to analyse group by time interactions and to compare differences in changes within groups between different time points. After 6-month MCT, TRAIN showed greater improvements for all fitness variables (group effects p < 0.05, except for flexibility) when compared to the CON. During the 4-month detraining period, TRAIN significantly decreased their balance, upper-limb flexibility and upper and lower-limb strength (all p < 0.05). CON only decreased upper-limb flexibility. When accounting for frailty status in the TRAIN, the frail-prefrail showed lower adaptations to the training and were more affected by detraining than the robust. The presented MCT is a good strategy to improve fitness in this population, but its positive effects are limited in time. It is, therefore, critical to avoid detraining periods

    "Fat but powerful'' paradox: association of muscle power and adiposity markers with all-cause mortality in older adults from the EXERNET multicentre study

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    Objectives: To assess the influence of muscle power and adiposity on all-cause mortality risk and to evaluate the fat but powerful'' (F+P) (or fat but fit'') paradox in older adults. Methods: A total of 2563 older adults (65 €''91 years old) from the EXERNET multicentre study were included. Adiposity (body mass index (BMI), waist circumference, body fat percentage (BF%) and fat index), allometric and relative power (sit-to-stand muscle power test) and various covariates (age, sex, hypertension, smoking status and walking and sitting times per day) were registered at baseline. All-cause mortality was recorded during a median follow-up of 8.9 years. Participants were classified into four groups: lean and powerful (L+P), F+P, lean but weak and fat and weak (F+W). Cox proportional hazard regression models and adjusted HRs were calculated. Results: According to BMI and waist circumference, all-cause mortality risk was reduced in the F+P (HR=0.55 and 0.63, p=0.044 and 0.049, respectively) and L+P (HR=0.57 and 0.58, p=0.043 and 0.025, respectively) groups. According to BF%, all-cause mortality decreased in the L+P group (HR=0.53; p=0.021), and a trend for a reduction was reported in the F+P group (HR=0.57; p=0.060). According to fat index, a survival benefit was only noted in the L+P group (HR=0.50; p=0.049). Higher levels of relative power reduced all-cause mortality risk among older people (HR=0.63 and 0.53, p=0.006 and 0.011, respectively). Conclusion: Powerful older people exhibited a reduced 9-year all-cause mortality regardless of BMI, waist circumference and BF%. Obesity according to fat index blunted the survival benefits of being powerful

    Psychosocial factors related to physical activity in frail and prefrail elderly people

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    Background: Increased physical activity (PA) is a very important factor in a healthy aging lifestyle. Psychosocial factors have also a main role in the initiation and maintenance of this behavior, but nowadays its implications for frailty elderly people are unknown, therefore, the aim of this study was to identify the psychosociological variables of behavior change that influence the practice of (PA) in frail and prefrail elderly. Methods: A total of 103 frail and pre-frail elderly people (72 females) participated in this cross-sectional study, on the framework of the EXERNET-Elder3.0 project. Age ranged from 68–94 years (mean = 80.4 ± 5.9 years). Individualized face-to-face interviews according to the constructs of the Transtheoretical Model of Change (TTM) (decisional balance (DB) and self-efficacy (SE)], social support (SS) (family and friends) and outcome expectations (OE) were administered to all participants. Results: Significant differences were found in DB, perceived benefits (PBn), SE, family-related SS and OE as a function of stages of change (SoC) (p < 0.005), but no significant were found in perceived barriers (PBrr) (p = 0.259) and friends-related SS (p = 0.068). According to the Scheffé post-hoc test, those in advanced SoC (Action-Maintenance), scored higher than those in lower SoC (Precontemplation-Contemplation and Preparation). Conclusion: The scores obtained from the study variables differed according to the SoC, supporting the external validity for the use of the TTM in frailty elderly. Further research is needed to determine the impact of PBrr and friends-related SS on this people, as well as to identify the validity of this model in the long-term in this population
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