2,955 research outputs found

    A comparative study on the functional response of Wolbachia-infected and uninfected forms of the parasitoid wasp Trichogramma brassicae

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    Trichogramma species (Hymenoptera: Trichogrammatidae) are haplo-diploid egg parasitoids that are frequently used as biological control agents against lepidopteran pests. These wasps display two reproductive modes, including arrhenotoky (bisexuality) and thelytoky (unisexuality). Thelytokous forms are often associated with the presence of endosymbiotic Wolbachia bacteria. The use of thelytokous wasps has long been considered as a way to enhance the efficacy of biological control. The present study investigates the potential of a thelytokous Wolbachiainfected and an arrhenotokous uninfected Trichogramma brassicae Bezdenko strain as inundative biocontrol agents by evaluating their functional response towards different egg densities of the factitious host, the Angoumois grain moth, Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae). The results revealed a type II functional response for both strains in which parasitism efficiency decreases with host egg density because of an increasing host handling time. A model with an indicator variable was used to compare the parameters of Holling’s disc equation in different data sets. It was demonstrated that the two strains did not differ in host attack rate. However, the Wolbachia-infected strain did have an increased host handling time when compared to the bisexual strain. Some applied aspects of the findings are discusse

    Basic data report on the turbulent spread of heat & matter

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    CER71-72RSM-9.August 1971.Includes bibliographical references (page 75).United States Dept. of Interior Geological Survey, Water Resources Division in cooperation with the United States Environmental Protection Agency, National Thermal Pollution Research Program.The purpose of this report is to present the results of an investigation of the turbulent transport properties of heated and salt water jets in an open channel flow. The data were taken cooperatively by the U.S. Geological Survey and the Environmental Protection Agency. The data include measurement of the turbulence characteristics, longitudinal dispersion, and vertical and lateral turbulent diffusion. Three different boundary roughnesses were used in the investigation. The turbulence data includes the intensity of turbulence, Eulerian time scales, autocorrelation function distributions, space correlation distributions in the vertical and horizontal directions and space-time correlation function distributions in the longitudinal direction. Vertical and lateral turbulent diffusion data were obtained downstream from jets of three diameters, at four different jet strengths. Two tracer fluids, heated water and a neutrally buoyant salt solution were used. Only basic data are reported here. The extensive analysis of these results will be the subject of a future publication

    Assessing the impact of intra-cloud live migration on anomaly detection

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    Virtualized cloud environments have emerged as a necessity within modern unified ICT infrastructures and have established themselves as a reliable backbone for numerous always-on services. `Live' intra-cloud virtual-machine (VM) migration is a widely used technique for efficient resource management employed within modern cloud infrastructures. Despite the benefits of such functionality, there are still several security issues which have not yet been thoroughly assessed and quantified. We investigate the impact of live virtual-machine migration on state-of-the-art anomaly detection (AD) techniques (namely PCA and K-means), by evaluating live migration under various attack types and intensities. We find that the performance for both detectors degrades as shown by their Receiver Operating Characteristics (ROC) curves when intra-cloud live migration is initiated while VMs are under a netscan (NS) or a denial-of-service (DoS) attack

    First Detection of Nosema ceranae, a Microsporidian Protozoa of European Honeybees (Apis mellifera) In Iran

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    Background: Nosemosis of European honey bee (Apis mellifera) is present in bee colonies world­wide. Until recently, Nosema apis had been regarded as the causative agent of the disease, that causes heavy economic losses in apicultures. Nosema ceranae is an emerging microsporidian para­site of European honeybees, A. mellifera, but its distribution is not well known. Previously, nosemosis in honeybees in Iran was attributed exclusively to N. apis.Methods: Six Nosema positive samples (determined from light microscopy of spores) of adult worker bees from one province of Iran (Savadkouh- Mazandaran, northern Iran) were tested to determine Nosema species using previously- developed PCR primers of the 16 S rRNA gene. As it is difficult to distinguish N. ceranae and N. apis morphologically, a PCR assay based on 16 S ribosomal RNA has been used to differentiate N. apis and N. ceranae.Results: Only N. ceranae was found in all samples, indicating that this species present in Iran apiar­ies.Conclusion: This is the first report of N. ceranae in colonies of A. mellifera in Iran. It seems that intensive surveys are needed to determine the distribution and prevalence of N. ceranae in differ­ent regions of Iran

    Modified Heider Balance on Sparse Random Networks

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    The lack of signed random networks in standard balance studies has prompted us to extend the Hamiltonian of the standard balance model. Random networks with tunable parameters are suitable for better understanding the behavior of standard balance as an underlying dynamics. Moreover, the standard balance model in its original form does not allow preserving tensed triads in the network. Therefore, the thermal behavior of the balance model has been investigated on a fully connected signed network recently. It has been shown that the model undergoes an abrupt phase transition with temperature. Considering these two issues together, we examine the thermal behavior of the structural balance model defined on Erd\H{o}s-R\'enyi random networks. We provide a Mean-Field solution for the model. We observe a first-order phase transition with temperature, for both the sparse and densely connected networks. We detect two transition temperatures, TcoldT_{cold} and ThotT_{hot}, characterizing a hysteresis loop. We find that with increasing the network sparsity, both TcoldT_{cold} and ThotT_{hot} decrease. But the slope of decreasing ThotT_{hot} with sparsity is larger than the slope of decreasing TcoldT_{cold}. Hence, the hysteresis region gets narrower, until, in a certain sparsity, it disappears. We provide a phase diagram in the temperature-tie density plane to observe the meta-stable/coexistence region behavior more accurately. Then we justify our Mean-Field results with a series of Monte-Carlo simulations.Comment: 10 Pages, 5 Figure

    Wireless structural health monitoring (SHM) system for damage detection using ultrasonic guided waveform response

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    This paper presents an improved version of a wireless device embedded with a smart PZT sensor to detect flaws and structural defects on selected investigated structure. Smart PZT sensors were used as an actuator and sensor, coupled with two XBee's and one signal generator IC chip. Programme execution on transmitting and receiving the ultrasonic guided wave via the PZT sensor had been written in MATLAB. The developed source code is basically to receive serial data from one Xbee to another remote Xbee attached to the investigated structural system. The refined waveform response is utilised for prognosis of the true structural status. The 4-mm simulated holed into one of the aluminium structural plate is benchmarked with its pristine condition in validating the effectiveness of the developed SHM wireless module. Results showed that the wave is more even in non-defected area and disrupted in affected area. Ultrasonic waves increase continuously for non-destructive evaluation and structural health monitoring in various structural applications because the guided wave can propagate long distances and reach difficult-to-access regions; for inspecting porous and some non-porous materials ultrasonic waves attenuate fast and are very useful. Recent advances in ultrasonic wave application model and results are discussed in this paper

    Evolution of Communities in the Medical Sciences: Evidence from the Medical Words Network

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    BACKGROUND: Classification of medical sciences into its sub-branches is crucial for optimum administration of healthcare and specialty training. Due to the rapid and continuous evolution of medical sciences, development of unbiased tools for monitoring the evolution of medical disciplines is required. METHODOLOGY/PRINCIPAL FINDINGS: Network analysis was used to explore how the medical sciences have evolved between 1980 and 2015 based on the shared words contained in more than 9 million PubMed abstracts. The k-clique percolation method was used to extract local research communities within the network. Analysis of the shared vocabulary in research papers reflects the trends of collaboration and splintering among different disciplines in medicine. Our model identifies distinct communities within each discipline that preferentially collaborate with other communities within other domains of specialty, and overturns some common perceptions. CONCLUSIONS/SIGNIFICANCE: Our analysis provides a tool to assess growth, merging, splitting and contraction of research communities and can thereby serve as a guide to inform policymakers about funding and training in healthcare

    Defining and demonstrating a smart technology configuration to improve energy performance and occupant comfort in existing buildings: a conceptual framework

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    Purpose: To achieve the building and property by 2050, decarbonisation goals will now require a significant increase in the rate of improvement in the energy performance of buildings. Occupant behaviour is crucial. This study seeks to guide the application of smart building technology in existing building stock to support improved building energy performance and occupant comfort. Design/methodology/approach: This study follows a logical partitioning approach to the development of a schema for building energy performance and occupant comfort. A review of the literature is presented to identify the characteristics that label and structure the problem elements. A smart building technology framework is overlaid on the schema. The framework is then applied to configure and demonstrate an actual technology implementation for existing building stock. Findings: The developed schema represents the key components and relationships of building energy performance when combined with occupant comfort. This schema provides a basis for the definition of a smart building technologies framework for existing building stock. The study demonstrates a viable configuration of available smart building technologies that couple building energy performance with occupant comfort in the existing building stock. Technical limitations (such as relatively simple building management control regimes) and pragmatic limitations (such as change management issues) are noted for consideration. Originality/value: This is the first development of a schema to represent how building energy performance can be coupled with occupant comfort in existing building stock using smart building technologies. The demonstration study applies one of many possible technology configurations currently available, and promotes the use of open source applications with push-pull functionality. The schema provides a common basis and guide for future studies
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