Provisioning Spot Market Cloud Resources to Create Cost-effective Virtual Clusters

Infrastructure-as-a-Service providers are offering their unused resources in the form of variable-priced virtual machines (VMs), known as "spot instances", at prices significantly lower than their standard fixed-priced resources. To lease spot instances, users specify a maximum price they are willing to pay per hour and VMs will run only when the current price is lower than the user's bid. This paper proposes a resource allocation policy that addresses the problem of running deadline-constrained compute-intensive jobs on a pool of composed solely of spot instances, while exploiting variations in price and performance to run applications in a fast and economical way. Our policy relies on job runtime estimations to decide what are the best types of VMs to run each job and when jobs should run. Several estimation methods are evaluated and compared, using trace-based simulations, which take real price variation traces obtained from Amazon Web Services as input, as well as an application trace from the Parallel Workload Archive. Results demonstrate the effectiveness of running computational jobs on spot instances, at a fraction (up to 60% lower) of the price that would normally cost on fixed priced resources.Comment: 14 pages, 4 figures, 11th International Conference on Algorithms and Architectures for Parallel Processing (ICA3PP-11); Lecture Notes in Computer Science, Vol. 7016, 201

Determinação racial de duas populações de Heterodera glycines em solos de cerrados, no Estado de Goiás, Brasil.

O objetivo do trabalho foi a determinação racial das populações de H. glycines

Efeito de diferentes densidades populacionais de Heterodera glycines sobre a cultura de soja.

O objetivo do trabalho foi avaliar o efeito de diferentes densidades populacionais desse nematóide sobre a cultivar Doko RC.Suplemento. Edição dos Resumos do 31 Congresso Brasileiro de Fitopatologia, Fortaleza, 1998

A new experiment for the determination of the 18F(p,alpha) reaction rate at nova temperatures

The 18F(p,alpha) reaction was recognized as one of the most important for gamma ray astronomy in novae as it governs the early 511 keV emission. However, its rate remains largely uncertain at nova temperatures. A direct measurement of the cross section over the full range of nova energies is impossible because of its vanishing value at low energy and of the short 18F lifetime. Therefore, in order to better constrain this reaction rate, we have performed an indirect experiment taking advantage of the availability of a high purity and intense radioactive 18F beam at the Louvain La Neuve RIB facility. We present here the first results of the data analysis and discuss the consequences.Comment: Contribution to the Classical Novae Explosions conference, Sitges, Spain, 20-24 May 2002, 5 pages, 3 figure

Aphelenchoides besseyi causing leaf spot on cowpea under field conditions in Brazil.

Aphelenchoides besseyi was detected as the causal agent of foliar dark spots on cowpea plants growing in the field, and its pathogenicity was confirmed. The identity of the nematode was determined through morphological, morphometric, and molecular characterization, using species-specific primers Abess_11F/Abess_11R targeting 28S rDNA, which amplified a fragment of 570 bp. This is the first report of A. besseyi parasitizing cowpea under field conditions in Brazil

One-Step Isolation of Monoterpene Indole Alkaloids from Psychotria Leiocarpa Leaves and Their Antiviral Activity on Dengue Virus Type-2

The leaf MeOH extract of Psychotria leiocarpa (Rubiaceae) showed in vitro non-cytotoxic and anti-dengue virus serotype 2 (DENV2) activity in human hepatocarcinoma cell lineage (HepG2). A one-step and cost-effective reversed-phase solid-phase extraction method based on high-performance liquid chromatography (HPLC) parameters allowed the isolation, directly from this bioactive extract, of the monoterpene indole alkaloids: N-glucopyranosyl vincosamide (1), vincosamide (2) and strictosidinic acid (3). The chemical structures were characterized based on 1D and 2D nuclear magnetic resonance (NMR), UV and high-resolution mass spectra (HRMS). The methodology has also allowed yielding a polyphenolic-rich fraction that was analyzed by high-performance liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MS/MS) revealing two fiavonol triglycosides (4, 5) and three caffeoylquinic acid isomers (6-8). Compound 3 is reported for the first time in P leiocarpa and all the phenolic compounds (4-8) are described for the first time in the genus Psychotria. Compounds 1-3 showed to be non-cytotoxic and anti-dengue active towards DENV2, highlighting vincosamide (2).This work was supported by Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), processes No. E-26/111.373/2014 and E-26/203.225/2017. DGL and JOC thank Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), finance code 001, for their fellowships. TW thanks both CAPES and FAPERJ for his fellowships. The authors thank the NMR Lab of the Instituto de Pesquisas em Produtos Naturais, Universidade Federal do Rio de Janeiro for the NMR spectra and MSc Matheus Oliveira, Dr Marcelo M. Pereira and Dr Denise Freire for their support. Technical and staff support provided by SGIker (UPV/EHU, MICINN, GV/EJ, ESF) is also gratefully acknowledged