174 research outputs found

    Caída de bloques de hielo en los frentes del glaciar de casquete de la isla Livingston (Archipiélago de las Shetland del Sur). Detección por métodos sísmicos. Influencia de las variables ambientales

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    Se han utilizado los datos procedentes de una red (array) sísmica situada en la isla Livingston para estudiar la evolución de las caídas de bloques de hielo en los frentes de los glaciares (calving). Partiendo de que la causa fundamental de las caídas de bloques es el flujo del hielo, se ha estudiado la influencia de la temperatura ambiental, la variación del nivel de la marea, la humedad y la velocidad del viento sobre este fenómeno. Como principal conclusión se deduce que la temperatura ambiental es el factor que ejerce una mayor y más directa influencia sobre las caídas de los bloques de hielo.We used data from a seismic array to study the evolution of calving at Livingston Island. Starting with the idea that the flow is the main cause of calving, we examined the effect of temperature, tide, relative humidity and wind velocity on this phenomenon. Air temperature proved to be the most relevant parameter

    Understanding and Challenging Populist Negativity towards Politics: The Perspectives of British Citizens

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    This article adapts and develops the idea of a cynical or ‘stealth’ understanding of politics to explore how citizens’ estrangement from formal politics is processed cognitively through a populist lens. Earlier work has shown the widespread presence of stealth attitudes in the United States and Finland. We show that stealth attitudes are also well established in Britain, demonstrate their populist character and reveal that age, newspaper readership and concerns about governing practices help predict their adoption by individuals. Yet our survey findings also reveal a larger body of positive attitudes towards the practice of democracy suggesting that there is scope for challenging populist cynicism. We explore these so-called ‘sunshine’ attitudes and connect them to the reform options favoured by British citizens. If we are to challenge populist negativity towards politics, we conclude that improving the operation of representative politics is more important than offering citizens new forms of more deliberative participation

    Sector-based Fresnel zone plate with extended depth of focus

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    A Sector-based Fresnel zone plate consists of a binary diffractive lens composed of a mosaic of sectors of Fresnel zone plates with different focal distances. When these focal distances are linearly distributed within the sectors, dual focus is obtained. Besides, we explore the possibility to generate an extended depth-of-focus lens by using a cubic distribution of the focal distances assigned to the sectors and optimizing the weight factors given to the terms of the cubic polynomial. Finally, numerical simulations based on the Rayleigh-Sommerfeld approach are carried out and experimental verifications by using a Spatial Light Modulator are performed, showing high agreement. The proposed kind of zone plate has potential applications in different research fields such as microscopy, lithography, data storage, or imaging

    Electoral Volatility, Political Sophistication, Trust and Efficacy

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    In this article we investigate voter volatility and analyze the causes and motives of switching vote intentions. We test two main sets of variables linked to volatility in literature; political sophistication and ‘political (dis)satisfaction’. Results show that voters with low levels of political efficacy tend to switch more often, both within a campaign and between elections. In the analysis we differentiate between campaign volatility and inter-election volatility and by doing so show that the dynamics of a campaign have a profound impact on volatility. The campaign period is when the lowly sophisticated switch their vote intention. Those with higher levels of interest in politics have switched their intention before the campaign has started. The data for this analysis are from the three wave PartiRep Belgian Election Study (2009)

    Rationale and design of a randomised controlled trial evaluating the effectiveness of an exercise program to improve the quality of life of patients with heart failure in primary care : the EFICAR study protocol

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    Background: Quality of life (QoL) decreases as heart failure worsens, which is one of the greatest worries of these patients. Physical exercise has been shown to be safe for people with heart failure. Previous studies have tested heterogeneous exercise programs using different QoL instruments and reported inconsistent effects on QoL. The aim of this study is to evaluate the effectiveness of a new exercise program for people with heart failure (EFICAR), additional to the recommended optimal treatment in primary care, to improve QoL, functional capacity and control of cardiovascular risk factors. Methods/Design: Multicenter clinical trial in which 600 patients with heart failure in NYHA class II-IV will be randomized to two parallel groups: EFICAR and control. After being recruited, through the reference cardiology services, in six health centres from the Spanish Primary Care Prevention and Health Promotion Research Network (redIAPP), patients are followed for 1 year after the beginning of the intervention. Both groups receive the optimized treatment according to the European Society of Cardiology guidelines. In addition, the EFICAR group performs a 3 month supervised progressive exercise program with an aerobic (high-intensity intervals) and a strength component; and the programme continues linked with community resources for 9 months. The main outcome measure is the change in health-related QoL measured by the SF-36 and the Minnesota Living with Heart Failure Questionnaires at baseline, 3, 6 and 12 months. Secondary outcomes considered are changes in functional capacity measured by the 6-Minute Walking Test, cardiac structure (B-type natriuretic peptides), muscle strength and body composition. Both groups will be compared on an intention to treat basis, using multi-level longitudinal mixed models. Sex, age, social class, co-morbidity and cardiovascular risk factors will be considered as potential confounding and predictor variables. Discussion: A key challenges of this study is to guarantee the safety of the patients; however, the current scientific evidence supports the notion of there being no increase in the risk of decompensation, cardiac events, hospitalizations and deaths associated with exercise, but rather the opposite. Safety assurance will be based on an optimized standardised pharmacological therapy and health education for all the participants

    Inverse-designed dielectric cloaks for entanglement generation

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    We investigate the generation of entanglement between two quantum emitters through the inverse-design engineering of their photonic environment. By means of a topology-optimization approach acting at the level of the electromagnetic Dyadic Green's function, we generate dielectric cloaks operating at different inter-emitter distances and incoherent pumping strengths. We show that the structures obtained maximize the dissipative coupling between the emitters under extremely different Purcell factor conditions, and yield steady-state concurrence values much larger than those attainable in free space. Finally, we benchmark our design strategy by proving that the entanglement enabled by our devices approaches the limit of maximum-entangled-mixed-statesThis work was sponsored by the Spanish MCIN/AEI/10.13039/50110001033 and by “ERDF A way of making Europe” through Grant Nos. RTI2018-099737-B-I00 and CEX2018-000805-M (through the María de Maeztu program for Units of Excellence in R&D). The authors also acknowledge funding from the 2020 CAM Synergy Project Y2020/TCS-6545 (NanoQuCo-CM

    Caída de bloques de hielo en los frentes del glaciar de casquete de la isla Livingston (Archipiélago de las Shetland del Sur). Detección por métodos sísmicos. Influencia de las variables ambientales

    Get PDF
    We used data from a seismic array to study the evolution of calving at Livingston Island. Starting with the idea that the flow is the main cause of calving, we examined the effect of temperature, tide, relative humidity and wind velocity on this phenomenon. Air temperature proved to be the most relevant parameter

    Carrying rocks : Hoarding behaviour in the Gravettian occupation of Cova Gran de Santa Linya (SE Pyrenees)

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    Altres ajuts: Acord transformatiu CRUE-CSICCova Gran de Santa Linya is part of the project Human settlement during the Upper Pleistocene and Holocene in the Southeastern Pyrenees (PID 2019-104843GB-I00) and the 2017SGR-1357 research group. This research has been also supported by MINECO-FPU scholarships. Fieldwork was funded by Servei d'Arquelogia I Paleontologia from the Generalitat de Catalunya (CLT009/18/00012). We thank the support given by the Institute for Field Research, all volunteers that participate in the fieldwork, and the kind permission of the Societat de Munts de Santa Linya to authorize the excavation in Cova Gran.Lithic resources can be accumulated to form caches or hoards as an effective subsistence strategy in response to times of stress. Hoarding behaviour is the manifestation of foresighted mechanisms, and is one of the common and also little known strategies among forager groups. In this paper, we present the evidence of such behaviour: a deposit of raw material recovered from level 497C of the Cova Gran de Santa Linya (SE Pyrenees). The lithic hoard is made up of 27 chalcedony nodules that have been tested at the site and exhibit great variability in terms of size and shape. The geostatistical analysis applied to the accumulations of raw materials identified has allowed us to determine spatial relationships between different categories in the archaeological record, such as nodules and cores, and has yielded insight into the use of chalcedony in specific areas of the occupation. The archaeological data suggest that this stockpile of raw material functioned as small-scale storage, constituting one of the few references about hoarding behaviour during the Palaeolithic, and the first time it has been exhaustively described in the Gravettian on the Iberian Peninsula. The lithic hoard from the Cova Gran allows us to investigate the role played by raw material hoards in the planning of subsistence activities and the organisation of human occupations
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