3,830 research outputs found

    Distributed energy-aware resource allocation in multi-antenna multi-carrier interference networks with statistical CSI

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    Resource allocation for energy efficiency optimization in multi-carrier interference networks with multiple receive antennas is tackled. First, a one-hop network is considered, and then, the results are extended to the case of a two-hop network in which amplify-and-forward relaying is employed to enable communication. A distributed algorithm which optimizes a system-wide energy-efficient performance function, and which is guaranteed to converge to a stable equilibrium point, is provided. Unlike most previous works, in the definition of the energy efficiency, not only the users' transmit power but also the circuit power that is required to operate the devices is taken into account. All of the proposed procedures are guaranteed to converge and only require statistical channel state information, thus lending themselves to a distributed implementation. The asymptotic regime of a saturated network in which both the active users and the number of receive antennas deployed in each receiver grow large is also analyzed. Numerical results are provided to confirm the merits of the proposed algorithms

    Youth employment policies in Italy

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    The GAP-TPC

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    Several experiments have been conducted worldwide, with the goal of observing low-energy nuclear recoils induced by WIMPs scattering off target nuclei in ultra-sensitive, low-background detectors. In the last few decades noble liquid detectors designed to search for dark matter in the form of WIMPs have been extremely successful in improving their sensitivities and setting the best limits. One of the crucial problems to be faced for the development of large size (multi ton-scale) liquid argon experiments is the lack of reliable and low background cryogenic PMTs: their intrinsic radioactivity, cost, and borderline performance at 87 K rule them out as a possible candidate for photosensors. We propose a brand new concept of liquid argon-based detector for direct dark matter search: the Geiger-mode Avalanche Photodiode Time Projection Chamber (GAP-TPC) optimized in terms of residual radioactivity of the photosensors, energy and spatial resolution, light and charge collection efficiencyComment: 7 pages, 5 figures, Accepted for publication on JINS

    A Fast and Efficient Incremental Approach toward Dynamic Community Detection

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    Community detection is a discovery tool used by network scientists to analyze the structure of real-world networks. It seeks to identify natural divisions that may exist in the input networks that partition the vertices into coherent modules (or communities). While this problem space is rich with efficient algorithms and software, most of this literature caters to the static use-case where the underlying network does not change. However, many emerging real-world use-cases give rise to a need to incorporate dynamic graphs as inputs. In this paper, we present a fast and efficient incremental approach toward dynamic community detection. The key contribution is a generic technique called Δ−screening\Delta-screening, which examines the most recent batch of changes made to an input graph and selects a subset of vertices to reevaluate for potential community (re)assignment. This technique can be incorporated into any of the community detection methods that use modularity as its objective function for clustering. For demonstration purposes, we incorporated the technique into two well-known community detection tools. Our experiments demonstrate that our new incremental approach is able to generate performance speedups without compromising on the output quality (despite its heuristic nature). For instance, on a real-world network with 63M temporal edges (over 12 time steps), our approach was able to complete in 1056 seconds, yielding a 3x speedup over a baseline implementation. In addition to demonstrating the performance benefits, we also show how to use our approach to delineate appropriate intervals of temporal resolutions at which to analyze an input network

    Analysis of Devices for Thermal Energy Consumption Monitoring and Design of A Bench Test for their Characterization

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    Abstract The mandatory introduction in Italy of the accounting of consumption for heating and domestic hot water in centralized heating systems has determined the introduction on the market of many commercial solutions based on different measuring principles. In order to find a proper method for testing the solutions proposed by the vendors, in the present work the uncertainty of the results reachable with the different types of measuring devices has been evaluated. Based on the best theoretical results achievable with the different types of devices the scheme of a test bed for the characterization of commercial systems is proposed

    Gut modulator effects of Conyza bonariensis explain its traditional use in constipation and diarrhea

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    BACKGROUND AND OBJECTIVES: The current investigation was carried out to explore the pharmacological basis of the crude extract of Conyza bonariensis (Cb.Cr) for its use in constipation and diarrhea. MATERIALS AND METHODS: The plant extract of Conyza bonariensis (C. bonariensis) was prepared, isolated guinea-pig ileum and rabbit jejunum preparations were used to evaluate its gut modulator effects. RESULTS: The Cb.Cr (0.3-10 mg/mL) exhibited spasmogenic effect in isolated guinea-pig ileum preparation, which was about 19-84% of the acetylcholine maximum. Pretreatment of the tissues with atropine (0.1 µM) abolished the contractile effect, similar to acetylcholine. Among the fractions, only the butanol fraction exhibited atropine sensitive contractile effect. In isolated rabbit jejunum preparations, Cb.Cr produced appreciable atropine-sensitive spasmogenic effect at lower concentrations (0.03-0.3 mg/mL) followed by spasmolytic effect at next higher concentration (1.0 and 3.0 mg/mL). Cb.Cr caused an inhibition of the high K+ induced contraction in isolated rabbit jejunum preparation with EC50 value of 0.62 mg/mL. Similarly, verapamil, a standard calcium blocker, inhibited high K+ induced contraction in isolated rabbit jejunum preparations. Cb.Cr caused a right ward shift in the Ca++ concentration response curve, similar to verapamil. Among various fractions of C. bonariensis, only hexane and ethylacetate fractions showed spasmolytic effects. CONCLUSIONS: The crude extract of C. bonariensis contains spasmogenic and spasmolytic constituents, which explains its medicinal use in constipation and diarrhe

    Giant melanoma of the abdomen: case report and revision of the published cases.

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    Malignant melanoma presenting as a giant cutaneous mass is rarely observed in clinical practice. A few patients with giant melanoma have been reported, Herein, we document our experience with a patient with giant cutaneous melanoma of the abdomen and review the features of previously reported individuals

    Giant melanoma of the abdomen: case report and revision of the published cases.

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    Malignant melanoma presenting as a giant cutaneous mass is rarely observed in clinical practice. A few patients with giant melanoma have been reported, Herein, we document our experience with a patient with giant cutaneous melanoma of the abdomen and review the features of previously reported individuals

    Comparison of caecal and faeces fermentation characteristics of ostrich by in vitro gas production technique

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    To compare caecal and faecal fermentation characteristics, ostrich caecal content (CI) and faeces (FI) were used as inocula for an in vitro gas production trial in which four substrates (dehydrated alfalfa, alfalfa hay, maize and a commercial concentrate) were tested. The fermentation characteristics (degraded organic matter, OMd; potential gas production, A; acetate; branched chain proportion, BCP) were studied by inoculum and substrate. CI and FI showed significant differences for almost all the fermentation parameters, and CI had higher values than FI for OMd (76.83 vs. 72.79%, p<0.01), A (250.3 vs. 229.3 ml/g, p<0.01), acetate (57.91 vs. 53.20 mmol/l, p<0.01) and BCP (0.031 vs. 0.027, p<0.05). CI and FI showed differences in carbohydrates and protein fermentation, but the interaction between the tested effects was not significant. The regression equations to estimate caecal fermentation characteristics from faeces suggest the possibility to use faeces as inoculum alternative to faeces. © 2011 Taylor & Francis

    Cutaneous melanoma frequencies and seasonal trend in 20 years of observation of a population characterised by excessive sun exposure

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    Background. Cutaneous melanoma is an aggressive form of skin cancer. It has become an increasingly common neoplasm in the most developed countries, especially among individuals of European origin. Patients and methods. Anonymous data of patients with cutaneous melanoma were collected from the diagnostic database of the University Hospital of Trieste from 1 January 1990 to 10 December 2013. Our study is based on a population which was constant over the period of observation; it was also well-defined and characterised by unrestrained sun exposure. Results. The number of cutaneous melanomas increased during the period of observation with a seasonality trend and gender related differences both for anatomical sites distribution and stage of the disease. Moreover, 6% of our cohort developed multiple melanomas. Conclusions. In a well-defined population devoted to excessive sun exposure the frequencies of skin melanomas roughly doubled from 1990 to 2013 following a seasonal trend. In that population, prevention efforts according to gender specific risk behaviour, as well as follow-up programmes both for evaluation of metastatic spreading and for early diagnosis of additional skin melanomas, are crucial due to gender specific differences and to the occurrence of multiple melanomas. \ua9 2015 Serena Bonin et al., published by De Gruyter Open
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