2,533 research outputs found

    Buprestidae, Cerambycidae, and Scolytidae Associated with Successive Stages of \u3ci\u3eAgrilus Bilineatus\u3c/i\u3e (Coleoptera: Buprestidae) Infestation of Oaks in Wisconsin

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    The species of Buprestidae, Cerambycidae, and Scolytidae found in association with Agrilus bilineatus (Weber) in declining oaks, Quercus spp., in Wisconsin, were Chrysobothris femorata (Olivier) and Dicerca sp. (Buprestidae); Amniscus macula (Say),Cyrtaphorus verrucosus (Olivier), Euderces picipes (Fabricius), Graphisurus fasciatus (DeGeer), Neodytus acuminatus (Fabricius), Sarosesthes fulminans (Fabricius), and Xylotrechus colonus (Fabricius) (Cerambycidae); and Monarthrum fasciatum (Say), Monarthrum mali (Fitch), Pseudopityophthorus minutissimus (Zimmerman), and Xylaterinus politus (Say) (Scolytidae). In general, weakened oaks were first attacked by A. bilineatus. and at times that same year by C. femorata. G. fasdalus, and P. minutissimus. Infestation by M.fasciatum, M. mali, and X. politus began the season following first attack by A. bilineatus. With the exception of A. bilineatus, the above mentioned Buprestidae and Cerambycidae appeared to preferentially infest dead wood, often those portions that had died the previous season

    Observations of the Biology of \u3ci\u3ePhasgonophora Sulcata\u3c/i\u3e (Hymenoptera: Chalcididae), a Larval Parasitoid of the Twolined Chestnut Borer, \u3ci\u3eAgrilus Bilineatus\u3c/i\u3e (Coleoptera: Buprestidae), in Wisconsin

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    Phasgorzophora sulcata Westwood was the principal larval parasitoid of Agrilus bilineatus (Weber) during a study conducted in a natural oak-hardwood forest in the Kettle Moraine State Forest, Jefferson County, Wisconsin. Mean percent larval parasitism was 10.5%. Mean A. bilineatus and P. sulcata densities were, respectively, 53.0 and 6.1 adults per square meter of bark. The theoretical developmental threshold temperatures for over- wintering A. bilineatus and P. sulcata larvae were 17.8 and 19.l0C, respectively. The peak flight period of P. sulcata (9 July 1980) occurred ca. 3 weeks after the A. bilineatus peak flight (18 June 1980) at about the time of peak A. bilineatus egg eclosion. The P. sulcata sex ratios (malexfemales) for laboratory-reared and field-captured adults were 1:1.35 and 1:3.22, respectively

    PEDAGOGICAL PRAXIS IN AN AGE OF PRIVATIZATION: THE CONTRADICTION OF CHARTER SCHOOLS

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    This study investigates a perceived inconsistency between pedagogical theory and uncritical practice in education, specifically in charter schools. The researcher reflects on the historical creation of charter schools to fulfill the needs of struggling students in contrast to a perception of modern charter schools that are more rigorous or specialized. The study includes thematically coded interview data from five Midwestern charter school educators in conjunction with site visits including two unspecified charters and two Montessori charters. Educators are asked to describe their evolving teaching philosophies, views on the purposes of education, and identify differences between charter schools and traditional public schools. Three primary themes emerged in educator rhetoric including: 1. instruction of values, 2. language charged by the free-market metaphor, and 3. issues of access for ESL and disabled students. The conclusion posits that homogenous teaching theory can result in uncritical practice and education reforms that do not meet the needs of all students. Thus, not meeting the original vision of charter schools. Themes are analyzed using the critical theory of Louis Althusser who identifies ideological systems and Paulo Freire who discusses the goals of public education as a “democratizing” experience

    Understanding trade pathways to target biosecurity surveillance

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    Increasing trends in global trade make it extremely difficult to prevent the entry of all potential invasive species (IS). Establishing early detection strategies thus becomes an important part of the continuum used to reduce the introduction of invasive species. One part necessary to ensure the success of these strategies is the determination of priority survey areas based on invasion pressure. We used a pathway-centred conceptual model of pest invasion to address these questions: what role does global trade play in invasion pressure of plant ecosystems and how could an understanding of this role be used to enhance early detection strategies? We concluded that the relative level of invasion pressure for destination ecosystems can be influenced by the intensity of pathway usage (import volume and frequency), the number and type of pathways with a similar destination, and the number of different ecological regions that serve as the source for imports to the same destination. As these factors increase, pressure typically intensifies because of increasing a) propagule pressure, b) likelihood of transporting pests with higher intrinsic invasion potential, and c) likelihood of transporting pests into ecosystems with higher invasibility. We used maritime containerized imports of live plants into the contiguous U.S. as a case study to illustrate the practical implications of the model to determine hotspot areas of relative invasion pressure for agricultural and forest ecosystems (two ecosystems with high potential invasibility). Our results illustrated the importance of how a pathway-centred model could be used to highlight potential target areas for early detection strategies for IS. Many of the hotspots in agricultural and forest ecosystems were within major U.S. metropolitan areas. Invasion ecologists can utilize pathway-centred conceptual models to a) better understand the role of human-mediated pathways in pest establishment, b) enhance current methodologies for IS risk analysis, and c) develop strategies for IS early detection-rapid response programs

    Parity detection and entanglement with a Mach-Zehnder interferometer

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    A parity meter projects the state of two qubits onto two subspaces with different parities, the states in each parity class being indistinguishable. It has application in quantum information for its entanglement properties. In our work we consider the electronic Mach-Zehnder interferometer (MZI) coupled capacitively to two double quantum dots (DQDs), one on each arm of the MZI. These charge qubits couple linearly to the charge in the arms of the MZI. A key advantage of an MZI is that the qubits are well separated in distance so that mutual interaction between them is avoided. Assuming equal coupling between both DQDs and the arms and the same bias for each DQD, this setup usually detects three different currents, one for the odd states and two for each even state. Controlling the magnetic flux of the MZI, we can operate the MZI as a parity meter: only two currents are measured at the output, one for each parity class. In this configuration, the MZI acts as an ideal detector, its Heisenberg efficiency being maximal. For a class of initial states, the initially unentangled DQDs become entangled through the parity measurement process with probability one.Comment: 9 pages, 2 figure

    Electron Waiting Times in Mesoscopic Conductors

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    Electron transport in mesoscopic conductors has traditionally involved investigations of the mean current and the fluctuations of the current. A complementary view on charge transport is provided by the distribution of waiting times between charge carriers, but a proper theoretical framework for coherent electronic systems has so far been lacking. Here we develop a quantum theory of electron waiting times in mesoscopic conductors expressed by a compact determinant formula. We illustrate our methodology by calculating the waiting time distribution for a quantum point contact and find a cross-over from Wigner-Dyson statistics at full transmission to Poisson statistics close to pinch-off. Even when the low-frequency transport is noiseless, the electrons are not equally spaced in time due to their inherent wave nature. We discuss the implications for renewal theory in mesoscopic systems and point out several analogies with energy level statistics and random matrix theory.Comment: 4+ pages, 3 figure

    Galilean type IIA backgrounds and a map

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    We obtain non-relativistic AdS4 X CP3 solutions with dynamical exponent 3 in type IIA string theory, both with and without Romans mass. The compactifications to four dimensions are found to describe Proca fields in anti-de Sitter spacetime. This leads us to conclude that the massive and massless IIA theories should be identified in four dimensions and the Romans mass should be identified with the `flux' along CP3 in a definite manner. From supergravity point of view, it is suggestive of some four-dimensional symmetry that rotates Romans mass into the flux along CP3. We also provide M-theory Galilean ABJM background which gives rise to the nonrelativistic type IIA solution.Comment: 10 pages;v2: major revisions, errors on supersymmetry corrected and references added; to be published in MPL

    "If chemists don’t do it, who is going to?" Peer-driven occupational change and the emergence of green chemistry

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    Occupational membership guides what people do, how they think of themselves, and how they interact in organizations and with society. While a rich literature explains how occupations adapt in response to external triggers for change, we have limited insight into how occupational incumbents, absent external triggers, work to influence how their peers do their work. We investigate the emergence and growth of “green chemistry,” an effort by chemists to encourage other chemists to reduce the health, safety, and environmental impacts of chemical products and processes. We find that advocates simultaneously advanced normalizing, moralizing, and pragmatizing frames for green chemistry and that each frame resonated differently with chemists in their various occupational roles. While this pluralistic approach generated broad acceptance of the change effort, it also exposed tensions, which threatened the coherence of the change. Divergent responses of advocates to these tensions contribute to a persistent state of pluralism and dynamism in the change effort. We discuss implications for theory on occupational change arising from our attention to internally-generated peer-driven change, heterogeneity within occupations, and change efforts that moralize occupational work.Meyer Fund for Sustainability grant (University of Oregon
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