MAGIC and Fermi-LAT gamma-ray results on unassociated HAWC sources

The HAWC Collaboration released the 2HWC catalogue of TeV sources, in which 19 show no association with any known high-energy (HE; E greater than or similar to 10 GeV) or very-high-energy (VHE; E greater than or similar to 300 GeV) sources. This catalogue motivated follow-up studies by both the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) and Fermi-LAT (Large Area Telescope) observatories with the aim of investigating gamma-ray emission over a broad energy band. In this paper, we report the results from the first joint work between High Altitude Water Cherenkov (HAWC), MAGIC, and Fermi-LAT on three unassociated HAWC sources: 2HWC J2006+341, 2HWC J1907+084*, and 2HWC J1852+013*. Although no significant detection was found in the HE and VHE regimes, this investigation shows that a minimum 1 degrees extension (at 95 per cent confidence level) and harder spectrum in the GeV than the one extrapolated from HAWC results are required in the case of 2HWC J1852+013*, whilst a simply minimum extension of 0.16 degrees (at 95 per cent confidence level) can already explain the scenario proposed by HAWC for the remaining sources. Moreover, the hypothesis that these sources are pulsar wind nebulae is also investigated in detail

Cost-optimized parallel computations using volatile cloud resources

In recent years, the parallel computing community has shown increasing interest in leveraging cloud resources for executing parallel applications. Clouds exhibit several fundamental features of economic value, like on-demand resource provisioning and a pay-per-use model. Additionally, several cloud providers offer their resources with significant discounts; however, possessing limited availability. Such volatile resources are an auspicious opportunity to reduce the costs arising from computations, thus achieving higher cost efficiency. In this paper, we propose a cost model for quantifying the monetary costs of executing parallel applications in cloud environments, leveraging volatile resources. Using this cost model, one is able to determine a configuration of a cloud-based parallel system that minimizes the total costs of executing an application

Heart Group To Hear Page

Newspaper article concerning the dean of the Medical College of Ohio speaking at an Ohio Heart Association meeting.

Development and operation of elastic parallel tree search applications using TASKWORK

Cloud resources can be dynamically provisioned according to application-specific requirements and are payed on a per-use basis. This gives rise to a new concept for parallel processing: Elastic parallel computations. However, it is still an open research question to which extent parallel applications can benefit from elastic scaling, which requires resource adaptation at runtime and corresponding coordination mechanisms. In this work, we analyze how to address these system-level challenges in the context of developing and operating elastic parallel tree search applications. Based on our findings, we discuss the design and implementation of TASKWORK, a cloud-aware runtime system specifically designed for elastic parallel tree search, which enables the implementation of elastic applications by means of higher-level development frameworks. We show how to implement an elastic parallel branch-and-bound application based on an exemplary development framework and report on our experimental evaluation that also considers several benchmarks for parallel tree search

Oligochaeta (Annelida, Clitellata) in lotic environments in the state of São Paulo, Brazil Oligochaeta (Annelida, Clitellata) em ambientes lóticos do estado de São Paulo, Brasil

Despite the importance of Oligochaeta to the dynamics of aquatic ecosystems and to studies of the biology of pollution, there is currently a dearth of information on this group's ecology in Brazil. The aim of this study was to describe the Oligochaeta fauna in four watercourses - three urban and one rural - in the state of São Paulo: the Pinheirinho stream, the Água Branca stream, the Monjolinho River and the Gouveia stream, respectively. Sediment samples were taken with a Van Veen grab in two areas from each watercourse, during the summer and winter of 2001. In all collection areas, measurements of the pH, electrical conductivity, dissolved oxygen and turbidity of the water were made with a Horiba U-10 device. Principal component analysis showed that axes 1 and 2 explained 68.18% of the results' variability, with the first axis predominantly associated with the granulometric data and the second one with the limnological data. Cluster analysis indicated that area II of the Monjolinho River differed from the other collection sites. In the present study, the Oligochaeta group was represented by Tubificidae, Naididae, Alluroididae, Narapidae and Enchytraeidae. Among the three species of Tubificidae, Limnodrilus hoffmeisteri Claparede, 1862, was the most abundant and most frequent species. The results provided important information on the ecology and distribution of limnic Oligochaeta.<br>Apesar da importância dos Oligochaeta para a dinâmica dos ecossistemas aquáticos e para os estudos sobre a biologia da poluição, existe atualmente, no Brasil, uma carência de informação sobre a ecologia desse grupo. O objetivo do estudo foi caracterizar a fauna de Oligochaeta em três córregos urbanos e um córrego rural, localizados na região central do Estado de São Paulo, sendo estes o córrego do Pinheirinho, Água Branca, rio Monjolinho e o córrego do Gouveia, respectivamente. Amostras do sedimento foram obtidas com um pegador Van Veen em duas áreas, durante o verão e inverno de 2001, em cada um dos ambientes estudados. Em todas as áreas de coletas foram tomadas medidas de pH, condutividade elétrica, oxigênio dissolvido e turbidez da água com o aparelho U-10 Horiba. A análise de componentes principais mostrou que os eixos I e II explicaram 68,18% da variabilidade dos resultados, sendo que, o primeiro eixo foi predominantemente explicado pelas variáveis granulométricas e o segundo eixo pelas variáveis limnológicas. A análise de agrupamento indicou que a área II do rio Monjolinho diferiu dos demais pontos de coleta. No presente estudo, o grupo Oligochaeta foi representado pelas famílias Tubificidae, Naididae, Alluroididae, Narapidae e Enchytraeidae. Entre as três espécies de Tubificidae, Limnodrilus hoffmeisteri Claparede, 1862 foi a mais abundante e mais freqüente. Os resultados forneceram informações importantes sobre a ecologia e distribuição de Oligochaeta límnicos