46 research outputs found

    The anatomy of urban social networks and its implications in the searchability problem

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    The appearance of large geolocated communication datasets has recently increased our understanding of how social networks relate to their physical space. However, many recurrently reported properties, such as the spatial clustering of network communities, have not yet been systematically tested at different scales. In this work we analyze the social network structure of over 25 million phone users from three countries at three different scales: country, provinces and cities. We consistently find that this last urban scenario presents significant differences to common knowledge about social networks. First, the emergence of a giant component in the network seems to be controlled by whether or not the network spans over the entire urban border, almost independently of the population or geographic extension of the city. Second, urban communities are much less geographically clustered than expected. These two findings shed new light on the widely-studied searchability in self-organized networks. By exhaustive simulation of decentralized search strategies we conclude that urban networks are searchable not through geographical proximity as their country-wide counterparts, but through an homophily-driven community structure

    Delineating Geographical Regions with Networks of Human Interactions in an Extensive Set of Countries

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    Large-scale networks of human interaction, in particular country-wide telephone call networks, can be used to redraw geographical maps by applying algorithms of topological community detection. The geographic projections of the emerging areas in a few recent studies on single regions have been suggested to share two distinct properties: first, they are cohesive, and second, they tend to closely follow socio-economic boundaries and are similar to existing political regions in size and number. Here we use an extended set of countries and clustering indices to quantify overlaps, providing ample additional evidence for these observations using phone data from countries of various scales across Europe, Asia, and Africa: France, the UK, Italy, Belgium, Portugal, Saudi Arabia, and Ivory Coast. In our analysis we use the known approach of partitioning country-wide networks, and an additional iterative partitioning of each of the first level communities into sub-communities, revealing that cohesiveness and matching of official regions can also be observed on a second level if spatial resolution of the data is high enough. The method has possible policy implications on the definition of the borderlines and sizes of administrative regions.National Science Foundation (U.S.)Singapore-MIT Alliance for Research and Technolog

    Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

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    Background: Low-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions. Results: A total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract. Conclusions: The pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine

    Vorrichtung und Verfahren zum Erfassen zumindest eines Vitalparameters einer Person; Vitalparametererfassungssystem

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    EP 2218395 A2 UPAB: 20100827 NOVELTY - The device has an optoelectronic sensor arrangement detecting a vital parameter by light transmission. The arrangement has a light-sensitive element (1') i.e. light sensor, and a light source (1) i.e. LED, which is arranged in a side part (110) of a support frame (120) of eyeglasses such that a direction of a maximum light output of the source corresponds to a shortest path (180) of the light from the source to the element. The element is arranged in another side part (110') of the frame, where one of the side parts (110') is provided opposite to the other side part (110). DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for detecting vital parameters of a person by an optoelectronic sensor arrangement. USE - Device for detecting vital parameters of a patient i.e. person, in a field of preventive, monitoring and accompanying medical care. Uses include but are not limited to arterial plethysmogram, heart rate, heart rate variability, oxygen content of arterial blood and pulse wave transmission time. ADVANTAGE - The light-sensitive element is arranged in one of the side parts of the support frame of the pair of spectacles and the light source is arranged in the other side part of the support frame such that the direction of the maximum light output of the light source corresponds to the shortest path of the light from the light source to the light-sensitive element, thus reducing the power requirement of the sensor arrangement. The device hence enables simple, efficient and reliable detection of the vital parameters with high quality even in stressful situations and situations of low blood pressure or hypothermia

    Are call detail records biased for sampling human mobility?

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