37,193 research outputs found

    Xyloryctes Hope, 1837 (Coleoptera: Scarabaeidae: Dynastinae: Oryctini) in the United States. Qui es et ubi fuisti et quo vadis?

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    Two species of Xyloryctes occur in the United States: X. jamaicensis (Drury) and X. thestalus Bates. Identification and distribution of these species has long been confused but is reviewed and clarified here. Xyloryctes jamaicensis occurs only in the eastern half of the U.S. and not in the southwestern U.S. as previously thought, while X. thestalus occurs in Guatemala and southern Mexico northwards to the southwestern United States. This hypothesis is corroborated by biogeographical and host plant data. Three new synonyms are listed for X. thestalus: X. faunus Casey 1915, X. hebes Casey 1915, and X. thestalus borealis Endrödi. The decline of Fraxinus spp., the food plant of Xyloryctes species, as a result of damage caused by the introduced emerald ash borer (Agrilus planipennis Fairmaire; Buprestidae) in the United States might portend a similar decline for Xyloryctes species in North America

    Forecasting with Econometric Methods: Folklore versus Fact

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    Evidence from social psychology suggests that econometricians will avoid evidence that disconfirms their beliefs. Two beliefs of econometricians were examined: (1) Econometric methods provide more accurate short-term forecasts than do other methods; and (2) more complex econometric methods yield more accurate forecasts. A survey of 21 experts in econometrics found that 95% agreed with the first statement and 72% agreed with the second. A review of the published empirical evidence yielded little support for either of the two statements in the 41 studies. The method of multiple hypotheses was suggested as a research strategy that will lead to more effective use of disconfirming evidence. Although this strategy was suggested in 1890, it has only recently been used by econometricians

    Reframing Turnover/Personality Research in the Context of the Attraction-Selection-Attrition Hypothesis

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    This paper re-examines data originally reported by Cowan & Dreher (1983) in their examination of personality correlates of turnover among managerial, professional, and technical employees. It is intended to reframe the relationship between personality and turnover in light of recent attention on the attraction-selection-attrition hypothesis and to make the results of the original study more accessable to those studying these issues. Results show no relationship between homogeneity based on personality dimensions measured by the Guilford-Zimmerman Temperament Survey (GZTS) and attrition from the organization. Therefore, no support can be offered for the homogeneity hypothesis. Based on these and other failures to find significant relationships between personality dimensions and homogeneity, we suggest that future research about the causes and effects of homogeneity should be based on research that delineates the domain of organizational fit

    Montage : eine Bibliographie

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    Kompiliert von Hans J. Wulff Inhalt: 1. Montage 2. Montageexperiment

    Presidential Advice and Information: Policy and Program Formulation

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    Remote sensing of changes in morphology and physiology of trees under stress

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    Measurements on foliage samples collected from several drought and salt treated plants revealed that leaf thickness decreased with increasing severity of the drought treatment and increased with increasing severity of treatment with NaCl, but remained essentially unaffected by treatment with CaCl2. Airborne data collected by multispectral scanner indicated that false color images provide selective enhancement of a diseased area. Comparison of simulated and actual aerial color and color IR photography revealed that the color renditions of the MSS simulations agreed closely with those of the actual photography

    A general review of concepts for reducing skin friction, including recommendations for future studies

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    Four main concepts which have significantly reduced skin friction in experimental studies are discussed; suction, gaseous injection, particle additives, and compliant wall. It is considered possible that each of these concepts could be developed and applied in viable skin friction reduction systems for aircraft application. Problem areas with each concept are discussed, and recommendations for future studies are made

    Second coefficient of viscosity in air

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    Acoustic attenuation measurements in air were analyzed in order to estimate the second coefficient of viscosity. Data over a temperature range of 11 C to 50 C and at relative humidities between 6 percent and 91 percent were used. This analysis showed that the second coefficient of viscosity varied between 1900 and 20,000 times larger than the dynamic or first coefficient of viscosity over the temperature and humidity range of the data. In addition, the data showed that the molecular relaxation effects, which are responsible for the magnitude of the second coefficient of viscosity, place severe limits on the use of time-independent, thermodynamic equations of state. Compressible flows containing large streamwise velocity gradients, like shock waves, which cause significant changes in particle properties to occur during time intervals shorter than hundredths of seconds, must be modeled using dynamic equations of state. The dynamic model approach is described briefly

    A speculum of chymical practice: Isaac Newton, Martin Lister (1639 −1712), and the making of telescopic mirrors

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    In 1674 the natural philosopher and physician Martin Lister published a new method of making glass of antimony for telescopic mirrors, using Derbyshire cawk or barite as a flux. New manuscript evidence reveals that Sir Isaac Newton requested samples of the cawk and antimony from Lister through an intermediary named Nathaniel Johnston. An analysis of Lister’s paper and Johnston’s correspondence and its context reveals insights not only about Newton’s work with telescopic specula but also about his alchemical investigations. Analysing these sources also contributes to our understanding of the nature of correspondence networks in the early ‘scientific revolution’ in England
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