10,563 research outputs found

    Defensive Weapons and Star Wars: A Supergame with Optimal Punishments

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    We model the perspective faced by nuclear powers involved in a supergame where nuclear deterrence is used to stabilise peace. This setting allows us to investigate the bearings of defensive weapons on the effectiveness of deterrence and peace stability, relying on one-shot optimal punishments. We find that the sustainability of peace is unaffected by defensive shields if both countries have them, while a unilateral endowment of such weapons has destabilising consequences.

    Error analysis for Mariner Venus/Mercury 1973 conducted at the JPL Mesa west antenna range

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    Theoretical analysis and experimental data are combined to yield the errors to be used with antenna gain, antenna patterns, and RF cable insertion loss measurements for the Mariner Venus-Mercury 1973 Flight Project. These errors apply to measurements conducted at the JPL Mesa, West Antenna Range, on the high gain antenna, low gain antenna, and RF coaxial cables

    Latest‐Late Fertility? Decline and Resurgence of Late Parenthood Across the Low‐Fertility Countries

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    After decades of fertility postponement, we investigate recent changes in late parenthood across low-fertility countries in the light of observations from the past. We use long series of age-specific fertility rates from the Human Fertility Database (1950– 2016) for women, and new data covering the period 1990–2016 for men. In 1950, the contribution of births at age 40 and over to female fertility rates ranged from 2.5 to 9 percent, but then fell sharply until the 1980s. From the 1990s, however, the prevalence of late first births increased rapidly, especially so in countries where it was initially lowest. This has produced a late fertility rebound in the last two decades, occurring much faster for women than for men. Comparisons between recent and past extremely late (age 48+) fertility levels confirm that people are now challenging the natural fertility barriers, particularly for a first child

    Finding lower bounds on the complexity of secret sharing schemes by linear programming

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    Optimizing the maximum, or average, length of the shares in relation to the length of the secret for every given access structure is a difficult and long-standing open problem in cryptology. Most of the known lower bounds on these parameters have been obtained by implicitly or explicitly using that every secret sharing scheme defines a polymatroid related to the access structure. The best bounds that can be obtained by this combinatorial method can be determined by using linear programming, and this can be effectively done for access structures on a small number of participants. By applying this linear programming approach, we improve some of the known lower bounds for the access structures on five participants and the graph access structures on six participants for which these parameters were still undetermined. Nevertheless, the lower bounds that are obtained by this combinatorial method are not tight in general. For some access structures, they can be improved by adding to the linear program non-Shannon information inequalities as new constraints. We obtain in this way new separation results for some graph access structures on eight participants and for some ports of non-representable matroids. Finally, we prove that, for two access structures on five participants, the combinatorial lower bound cannot be attained by any linear secret sharing schemePeer ReviewedPostprint (author's final draft

    Multilateral Resistance to Migration

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    The rate of migration observed between two countries does not depend solely on their relative attractiveness, but also on the one of alternative destinations. Following the trade literature, we term the influence exerted by other destinations on bilateral flows as Multilateral Resistance to Migration, and we show how it can be accounted for when estimating the determinants of migration flows in the context of a general individual random utility maximization model. We propose the use of the Common Correlated Effects estimator (Pesaran, 2006) and apply it to high-frequency data on the Spanish immigration boom between 1997 and 2009. Compared to more restrictive estimation strategies developed in the literature, the bias goes in the expected direction: we find a smaller effect of GDP per capita and a larger effect of migration policies on bilateral flows.international migration, economic determinants, migration policies, time-varying attractiveness, multiple destinations

    Adipocyte browning and higher mitochondrial function in peri-adrenal but not subcutaneous fat in pheochromocytoma

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    Context: Patients with pheochromocytoma (pheo) show presence of multilocular adipocytes that express uncoupling protein (UCP) 1 within periadrenal (pADR) and omental (OME) fat depots. It has been hypothesized that this is due to adrenergic stimulation by catecholamines produced by the pheo tumors. Objective: To characterize the prevalence and respiratory activity of brown-like adipocytes within pADR, OME and subcutaneous (SC) fat depots in human adult pheo patients. Design: This was an observational cohort study. Setting: University hospital. Patients: We studied 46 patients who underwent surgery for benign adrenal tumors (21pheos and 25 controls with adrenocortical adenomas). Main outcome measure: We characterized adipocyte browning in pADR, SC, and OME fat depots for histological and immunohistological features, mitochondrial respiration rate, and gene expression. We also determined circulating levels of catecholamines and other browning-related hormones. Results: 11 of 21 pheo pADR adipose samples, but only 1 of 25 pADR samples from control patients, exhibited multilocular adipocytes. The pADR browning phenotype was associated with higher plasma catecholamines and raised UCP1. Mitochondria from multilocular pADR fat of pheo patients exhibited increased rates of coupled and uncoupled respiration. Global gene expression analysis in pADR fat revealed enrichment in β-oxidation genes in pheo patients with multilocular adipocytes. No SC or OME fat depots exhibited aspects of browning. Conclusion: Browning of the pADR depot occurred in half of pheo patients and was associated with increased catecholamines and mitochondrial activity. No browning was detected in other fat depots, suggesting that other factors are required to promote browning in these depots

    Scientific electronic publishing in Cuba: a challenge that turned into a win

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    In 1992 Cuba was in its worst financial and economical crisis, which made it impossible to provide all Cuban hospitals and clinics even with international specialty journals. As an alternative it was decided to explore the possibilities electronic publishing could provide to alleviate this tough situation. As a response Infomed was born (http://www.sld.cu). Infomed is the national telematic network of the Public Health System in Cuba, based on a human knowledge network for health improvement. Its mission is to promote the high quality health care, education, research, and management by using the best available technologies. Moreover, Infomed integrates the Cuban Public Health System with the global network of health information. The action plan was to set up an integrated network of accessible health information in Cuba, based on new information technologies; to interconnect the most important Cuban health institutions and to connect them with Internet; to develop added value services in public health; and to integrate the Cuban public health experiences and results with the global electronic networks

    Experiments on applying relaxation labeling to map multilingual hierarchies

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    This paper explores the automatic construction of a multilingual Lexical Knowledge Base from preexisting lexical resources. This paper presents a new approach for linking already existing hierarchies. The Relaxation labeling algorithm is used to select --among all the candidate connections proposed by a bilingual dictionary-- the right conection for each node in the taxonomy.Postprint (published version

    SupWSD: a flexible toolkit for supervised word sense disambiguation

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    In this demonstration we present SupWSD, a Java API for supervised Word Sense Disambiguation (WSD). This toolkit includes the implementation of a state-of-the-art supervised WSD system, together with a Natural Language Processing pipeline for preprocessing and feature extraction. Our aim is to provide an easy-to-use tool for the research community, designed to be modular, fast and scalable for training and testing on large datasets. The source code of SupWSD is available at http://github.com/SI3P/SupWSD
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