Power management by load forecasting in web server clusters

The complexity and requirements of web applications are increasing in order to meet more sophisticated business models (web services and cloud computing, for instance). For this reason, characteristics such as performance, scalability and security are addressed in web server cluster design. Due to the rising energy costs and also to environmental concerns, energy consumption in this type of system has become a main issue. This paper shows energy consumption reduction techniques that use a load forecasting method, combined with DVFS (Dynamic Voltage and Frequency Scaling) and dynamic configuration techniques (turning servers on and off), in a soft real-time web server clustered environment. Our system promotes energy consumption reduction while maintaining user’s satisfaction with respect to request deadlines being met. The results obtained show that prediction capabilities increase the QoS (Quality of Service) of the system, while maintaining or improving the energy savings over state-of-the-art power management mechanisms. To validate this predictive policy, a web application running a real workload profile was deployed in an Apache server cluster testbed running Linux.     

Capturing Transition Paths and Transition States for Conformational Rearrangements in the Ribosome

To reveal the molecular determinants of biological function, one seeks to characterize the interactions that are formed in conformational and chemical transition states. In other words, what interactions govern the molecule’s energy landscape? To accomplish this, it is necessary to determine which degrees of freedom can unambiguously identify each transition state. Here, we perform simulations of large-scale aminoacyl-transfer RNA (aa-tRNA) rearrangements during accommodation on the ribosome and project the dynamics along experimentally accessible atomic distances. From this analysis, we obtain evidence for which coordinates capture the correct number of barrier-crossing events and accurately indicate when the aa-tRNA is on a transition path. Although a commonly used coordinate in single-molecule experiments performs poorly, this study implicates alternative coordinates along which rearrangements are accurately described as diffusive movements across a one-dimensional free-energy profile. From this, we provide the theoretical foundation required for single-molecule techniques to uncover the energy landscape governing aa-tRNA selection by the ribosome.     

Scanning electron microscoscopy of the second-instar larva of Gasterophilus nasalis

The second-instar larva of the bot fly Gasterophilus nasalis (L.) (Diptera: Gasterophilidae) is described for the first time, based on scanning electron microscope (SEM) studies. On the pseudocephalum the larva bears an antenomaxillary sensory complex formed by the antenna (coeloconic sensilla) and the maxillary palp with a set of six coeloconic sensilla and four basiconica sensilla. The oral opening is latero-posteriorly limited by small spines, and exhibits strongly ornamented maxillae and mandibles. The thoracic and abdominal segments are circled by two bands, each with two rows (except the last segment that has one row) of backwardly pointed spines, and have cuticular depressions. Trichoid and campaniform sensilla surround the larval segments. The anterior spiracular opening is a small aperture. The terminal end of the eighth abdominal segment shows a spiracular cavity, lateral tubercles, eight basiconic and two trichoid sensilla. Each spiracular plate has two slightly curved slits, each with a serrated rima. There is a probable ecdysial scar. The findings of this ultrastructural study are compared with those other of larval flies.     

Caprine arthritis-encephalitis virus (CAEV) detection in semen of endangered goat breeds by nested polymerase chain reaction

Semen and peripheral blood mononuclear cells (PBMCs) samples of four naturally infected, four experimentally infected (endangered breeds) and four non-infected bucks (endangered breeds) were evaluated for the presence of CAEV proviral-DNA by nested polymerase chain reaction (n-PCR). Three out of the eight PBMC samples from infected bucks were positive for CAEV-DNA and four out of the eight semen samples were positive for CAEV proviral-DNA. This is the first report describing the presence of CAEV proviral-DNA in semen from seropositive Anglo-Nubian, Moxotó and Canindé bucks, providing useful information towards the design of efficient methods to prevent CAEV dissemination in the endangered goat livestock genetic resources in Brazil.     

State-of-knowledge on Myracrodruon urundeuva Fr. Allemão (Anacardiaceae) for genetic conservation in Brazil

This study explores the basis for conservation action on Myracrodruon urundeuva Fr. Allemão (Anacardiaceae). This is a wide-ranging forest species occurring in Brazil and other South American countries, notably in the Cerrado region. This paper aims to provide a structured review of available knowledge of its biology, ecology, silviculture and management. Widely-scattered published reports have been critically considered and efforts made to highlight and resolve contradictions and inconsistencies. Information about this species is scanty and scattered, particularly in respect to its biology and ecology. Some effort has been applied to its domestication and improvement, but opinion on its silviculture and management is still controversial. The taxon is typical of open and deciduous forest in the Cerrado. Gaps in current knowledge relevant for conservation are identified and steps to fill them proposed. Where in situ conservation proved to be more appropriate, recommendations are made for the location of additional protected areas. Complementary ex situ and enrichment conservation actions are suggested for specific parts of the range where resource losses are already so extensive that in situ measures alone are inadvisable. Opportunities for refining the limited management and conservation knowledge are proposed by highlighting priorities for study of the taxon. Finally, future action is discussed in the context of the infrastructure of the national conservation sector.