5,513 research outputs found

    Utilization of solar energy in developing countries: Identifying some potential markets

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    The potential use of solar electricity generated from photovoltaic cells is examined for nineteen developing nations. Energy and economic profiles are summarized for each country. A comparison is made between the use of autogeneration and photovoltaics in a rural area of Haiti

    A promising biotechnical approach to pest management of the western corn rootworm in Illinois maize fields shielded with a MCA kairomone baited trap line

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    The leaf beetle Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), (D.v.v.), also called the western corn rootworm, is endemic to the New World and ranks among the top ten insect pests in worldwide grain production. D.v.v. causes annual damages of 1 billion US Dollars and is a notoriously difficult insect pest to control and manage, as entomological history of the past 50 years amply demonstrates (METCALF 1986). Considering recent emphasis on environmentally compatible and sustainable management strategies, entomologists and practitioners are encouraged to pay increased attention to novel approaches such as biotechnial methods which today are characterized by preferential use of signal compounds. Fortunately, both insect and plants provide a wide variety of such natural resources. In the case of D.v.v., sex pheromonesand plant kairomones as specific attractants and management tools are relatively well investigated through numerous contributions by GUSS et al. (1982), METCALF & METCALF (1992), METCALF (1994) and many recent publications on the advance and spread of D.v.v. within Europe (BERGER 1995-2004, HUMMEL 2003). Principle of MSD method: In this paper, the plant kairomone 4-methoxycinnamaldehyde (MCA), a specific attractant for D.v.v., is being used as a tool within the newly proposed "MSD" strategy. It combines a two pronge approach consisting as the well known mass trapping with the novel shielding and deflecting, called in short "diversion" and introduced here for the first time. An invisible “curtain” or “fence” of MCA vapor released from a MCA trap line establishes a behavioral barrier which the flying beetles cannot easily pass without being 1. either caught in one of the high capacity traps or 2. being diverted elsewhere. The net effect is a significant reduction in adult population density and oviposition within the MCA treated field as compared to an untreated control field. These effects can be experimentally measured by 1. adult beetle counts on maize plants, 2. by counts in independent monitoring traps baited with the D.v.v. sex pheromone, and 3. by egg counts taken in soil samples.Umweltgerechter und nachhaltiger Pflanzenschutz erfordert eine Vielzahl verschiedener Strategien zum Management von Schadinsekten auf ihren Wirtspflanzen. Insekten- und pflanzeneigene Signalstoffe sowie ihre synthetischen Analoga bieten einen nahezu unerschöpflichen Vorrat spezifischer Lockwirkungen und Interventionsmöglichkeiten an, der bisher leider nur unzureichend genutzt wird. Kürzliche Entdeckungen sowohl neuer Kairomon-Lockstoffe als auch neuer Verfahrensschritte für das Management des Westlichen Maiswurzelbohrers Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) (D.v.v.) erweitern das Spektrum anwendbarer Management- Optionen für diesen schwer bekämpfbaren Schädling im nordamerikanischen Maisanbau. Seit seiner Einschleppung nach Europa (ČAMPRAG & BAČA 1995) wird D.v.v. neuerdings auch zunehmend zum Problemschädling an Mais in Europa. Die neue "MSD"-Technik besteht aus einer Kombination von Massenabfang ("mass trapping"), Abschirmung ("shielding") und Umlenkung ("diversion") der Blattkäfer. Fallen hoher Fangkapazität, die das Kairomon 4-Methoxyzimtaldehyd (MCA) und Cucurbitacin- Pulver als fraßfördernden Stoff enthalten, können bei Aufstellung als "Fallenzaun" relativ geringer Dichte die Käfer so umlenken, dass zwischen den beiden Seiten dieses Zauns eine unsichtbare Geruchs-Barriere entsteht. Diese führt zu einer messbaren und signifikanten Verminderung der Käferzahl zwischen MCA behandelten Feldabschnitten gegenüber ihren unbehandelten Kontrollen. In 0,27 ha bzw. 0,12 ha großen Maisversuchsfeldern der Standorte Urbana und Champaign des US-Staates Illinois ließen sich während der Monate August und September 2003 und 2004 nach MCA-Behandlung gegenüber Kontrollen deutliche und signifikante Verminderungen von D.v.v. an Hand dreier Kriterien nachweisen: 1. Käferzahlen auf Maispflanzen innerhalb des "MSD-Feldes", 2. Käferzahlen in Sexuallockstoff-Fallen im MSD Feld und 3. die Zahl abgelegter D.v.v.-Eier im Boden des MSD Feldes nehmen ab. Der beobachtete Effekt läßt sich nicht allein auf die Populationsverminderung infolge hoher Abfangzahlen zurückführen. Es gibt darüber hinaus einen Abschirm- und Umlenkeffekt, dessen sinnes- und verhaltensphysiologische Mechanismen zusätzliche künftige Erforschungen erforderlich machen

    Predicting velocity growth: a time series perspective

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    Velocity of money ; Forecasting

    Electromagnetic effects on trace impurity transport in tokamak plasmas

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    Semi-leptonic decays heavy-light to heavy light

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    We present results for the QCD matrix elements involved in semi-leptonic decays of B-mesons into pseudo scalar heavy light states. The application of NRQCD heavy quarks allows for quark masses around the physical b-quark. We investigate the dependence of the form factors on the external momenta and looked at the mass dependence at zero recoil. For the first time, results for radially excited decay products are presented.Comment: 3 pages LaTeX, 5 figures, Talk given at LATTICE99(Heavy Quarks), June 29th to July 3rd, 1999, Pisa, Ital

    Rethinking the "Conspiracy Crisis": Use and Misuse of "Conspiracy Theory" Labels After Covid‐19

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    Against the backdrop of the Covid-19 pandemic, this article undertakes a critical evaluation of a series of shortcomings of the view of conspiracy theories that is predominant among scholars and the general public. Reviewing numerous studies on the topic, we critically assess: (a) how justified the claim is that we are in a conspiracy-thinking emergency, (b) how the label of conspiracy theorist can be weaponized to delegitimize heterodox views, and (c) the practical consequences, for academic research and the well-functioning of democracies, of unpopular ideas being labeled as conspiratorial. The empirical sources reviewed here suggest that beliefs in conspiracy theories have not increased over time and are less consequential than commonly believed, even in times of a global pandemic. Instead, the concept of conspiracy theory has become more prevalent and its derogatory connotation evokes a stigma that tilts the democratic playing field against dissenting viewpoints. The stigmatization and political leveraging of this notion, we argue, lead to biases not only in the public discussion on various sensitive topics but also in the academic literature on conspiracy theories themselves. We analyze these academic blind spots in light of the diminishing political diversity in academia and recent perspectives on scientific censorship. We propose to complement the research on conspiracy theorists with an analysis of individuals at the opposite end of the spectrum, who are inclined to systematically trust institutional authorities and are highly prejudiced against heterodox opinions. Proposed solutions include promoting balanced news coverage, fostering critical thinking through debates, and piercing information bubbles to provide access to diverse perspectives

    DC-assisted microwave quenching of YBa2Cu3O7-{\delta} coplanar waveguide to a highly dissipative state

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    The paper reports on finding the effect of a strong change in the microwave losses in an HTS-based coplanar waveguide (CPW) at certain values of the input power Pin and direct current Idc. CPW on the basis of 150 nm thick YBa2Cu3O7-{\delta} epitaxial film on a single crystal MgO substrate was studied experimentally. A sharp and reversible transition of the CPW into a strongly dissipative state at the certain meanings of Pin and Idc depending on temperature was observed. Apparently the effect can be explained by self-heating of HTS structure caused by magnetic flux flow under the joint influence of MW and DC.Comment: 9 pages, 5 figures, 17 reference

    The unquenched Upsilon spectrum

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    We describe the bottomonium spectrum obtained on the UKQCD dynamical ensembles and its comparison to quenched results. We include a determination of alpha_s and m_b from the dynmaical results.Comment: Lattice 2000 (Heavy Quark Physics
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