933 research outputs found

    Poles and zeros of the scattering matrix associated to defect modes

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    We analyze electromagnetic waves propagation in one-dimensional periodic media with single or periodic defects. The study is made both from the point of view of the modes and of the diffraction problem. We provide an explicit dispersion equation for the numerical calculation of the modes, and we establish a connection between modes and poles and zeros of the scattering matrix.Comment: 6 pages (Revtex), no figure

    Recalibrating the ‘world map’ of palliative care development

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    Background: Despite growing interest from policy makers, researchers and activists, there is still little science to underpin the global development of palliative care. This study presents the methods deployed in the creation of a ‘world map’ of palliative care development. Building on two previous iterations, with improved rigour and taking into account reviewers’ feedback, the aim of the study is to determine the level of palliative care development in 198 countries in 2017, whilst ensuring comparability with previous versions. We present methods of data collection and analysis. Methods and analysis: Primary data on the level of palliative care development in 2017 was collected from in-country experts through an online questionnaire and, where required, supplemented by published documentary sources and grey literature. Population and per capita opioid consumption data were derived from independent sources. Data analysis was conducted according to a new scoring system and algorithm developed by the research team. Ethics and dissemination: The study was approved by the University of Glasgow College of Social Sciences Research Ethics Committee. Findings of the study will be disseminated in peer-reviewed journals, as a contribution to the second edition of the Global Atlas of Palliative Care at the End-of-Life, and via social media, including the Glasgow End of Life Studies Group blog and the project website. Limitations of the study: There are potential biases associated with self-reporting by key in-country experts. In some countries, the identified key expert failed to complete the questionnaire in whole or part and data limitations were potentially compounded by language restrictions, as questionnaires were available only in three European languages. The study relied in part on data from independent sources, the accuracy of which could not be verified

    Influence Diffusion in Social Networks under Time Window Constraints

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    We study a combinatorial model of the spread of influence in networks that generalizes existing schemata recently proposed in the literature. In our model, agents change behaviors/opinions on the basis of information collected from their neighbors in a time interval of bounded size whereas agents are assumed to have unbounded memory in previously studied scenarios. In our mathematical framework, one is given a network G=(V,E)G=(V,E), an integer value t(v)t(v) for each node vVv\in V, and a time window size λ\lambda. The goal is to determine a small set of nodes (target set) that influences the whole graph. The spread of influence proceeds in rounds as follows: initially all nodes in the target set are influenced; subsequently, in each round, any uninfluenced node vv becomes influenced if the number of its neighbors that have been influenced in the previous λ\lambda rounds is greater than or equal to t(v)t(v). We prove that the problem of finding a minimum cardinality target set that influences the whole network GG is hard to approximate within a polylogarithmic factor. On the positive side, we design exact polynomial time algorithms for paths, rings, trees, and complete graphs.Comment: An extended abstract of a preliminary version of this paper appeared in: Proceedings of 20th International Colloquium on Structural Information and Communication Complexity (Sirocco 2013), Lectures Notes in Computer Science vol. 8179, T. Moscibroda and A.A. Rescigno (Eds.), pp. 141-152, 201

    Local Renal Circadian Clocks Control Fluid-Electrolyte Homeostasis and BP.

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    The circadian timing system is critically involved in the maintenance of fluid and electrolyte balance and BP control. However, the role of peripheral circadian clocks in these homeostatic mechanisms remains unknown. We addressed this question in a mouse model carrying a conditional allele of the circadian clock gene Bmal1 and expressing Cre recombinase under the endogenous Renin promoter (Bmal1(lox/lox)/Ren1(d)Cre mice). Analysis of Bmal1(lox/lox)/Ren1(d)Cre mice showed that the floxed Bmal1 allele was excised in the kidney. In the kidney, BMAL1 protein expression was absent in the renin-secreting granular cells of the juxtaglomerular apparatus and the collecting duct. A partial reduction of BMAL1 expression was observed in the medullary thick ascending limb. Functional analyses showed that Bmal1(lox/lox)/Ren1(d)Cre mice exhibited multiple abnormalities, including increased urine volume, changes in the circadian rhythm of urinary sodium excretion, increased GFR, and significantly reduced plasma aldosterone levels. These changes were accompanied by a reduction in BP. These results show that local renal circadian clocks control body fluid and BP homeostasis

    Mapping levels of Palliative Care development in 198 Countries: the situation in 2017

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    Context Palliative care is gaining ground globally and is endorsed in high-level policy commitments, but service provision, supporting policies, education, and funding are incommensurate with rapidly growing needs. Objectives The objective of this study was to describe current levels of global palliative care development and report on changes since 2006. Methods An online survey of experts in 198 countries generated 2017 data on 10 indicators of palliative care provision, fitted to six categories of development. Factor analysis and discriminant analysis showed the validity of the categorization. Spearman correlation analyses assessed the relationship with World Bank Income Level (WBIL), Human Development Index (HDI), and Universal Health Coverage (UHC). Results Numbers (percentages) of countries in each development category were as follows: 1) no known palliative care activity, 47 (24%); 2) capacity-building, 13 (7%); 3a) isolated provision, 65 (33%); 3b) generalized provision, 22 (11%); 4a) preliminary integration into mainstream provision, 21 (11%); 4b) advanced integration, 30 (15%). Development levels were significantly associated with WBIL (rS = 0.4785), UHC (rS = 0.5558), and HDI (rS = 0.5426) with P < 0.001. Net improvement between 2006 and 2017 saw 32 fewer countries in Categories 1/2, 16 more countries in 3a/3b, and 17 more countries in 4a/4b. Conclusion Palliative care at the highest level of provision is available for only 14% of the global population and is concentrated in European countries. An 87% global increase in serious health-related suffering amenable to palliative care interventions is predicted by 2060. With an increasing need, palliative care is not reaching the levels required by at least half of the global population

    Palliative care coverage across European National Health Systems: proposal of a synthetic indicator

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    Background: The coverage of palliative care (PC) may be understood as a country’s capacity to offer prevention and relief from serious health-related suffering in relation to an existing need. The aim of this study is to estimate European countries´ coverage capacities. Method: Secondary analysis of three indicators, including the number of specialized services (SSPC), integration capacity scores (ICS) and the PC needs. By means of a K-medians clustering supervised algorithm, three coverage profiles were obtained: (1) Advanced: countries with high ICS and SSPC, and low PC needs; (2) Limited: countries with low ICS and SSPC, and low PC needs; and (3) Low: countries with low ICS and SSPC and high PC needs. Results: On average, the ratio of specialized services per population was 0.79 per 100,000 inhabitants, the average ICS was 19.62 and the average number of deceased patients with SHS per 100,000 inhabitants was 5.69. Twenty countries (41%) reached an advanced coverage profile. Nine countries (18%) demonstrated a limited coverage profile; and 20 countries (41%) fell under a low-coverage capacity. Conclusion: The level of palliative care coverage across Europe shows that 59% of European countries have either limited or very low availability of PC resources as regards their palliative care needs

    Development of an atlas of palliative care in the Eastern Mediterranean Region through a stakeholder participative process

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    Background: The increasing number of people experiencing serious health-related suffering due to severe illness is an urgent issue in the WHO Eastern Mediterranean Region (EMR). Although palliative care can mitigate much of this suffering, its current development and indicators to measure progress remain unknown. Aims: To describe the development of the Atlas of palliative care in the Eastern Mediterranean Region 2021. Methods: Recently, the WHO Regional Office for the Eastern Mediterranean, together with a network of palliative care experts, identified the best indicators and collected data across the Region. These indicators include national palliative care strategies, number of specialized palliative care services per population, inclusion of palliative care in the health benefits package and national health budget, and the use of pain medication. These and other useful information form the Atlas of palliative care in the Eastern Mediterranean Region 2021. Results: The Atlas shows that provision of specialized palliative care services and pain medication in the Region is low. Several of the indicators suitable to the region are new and include the level of public awareness of palliative care, inclusion of palliative care in health insurance plans, availability of centres of excellence for palliative clinical care, and availability of grants to finance palliative care research. Conclusion: Adoption of favourable policies, educational initiatives, and the involvement of stakeholders, represent an opportunity for future development of palliative care in the EMR
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