178,328 research outputs found
Biological control of Otiorhynchus sulcatus by insect parasitic nematodes, Heterorhabditis spp., at low temperatures : a systems analytical approach
No full textThe black vine weevil, Otiorhynchus sulcatus, is an important pest in ornamentals and nursery stock in The Netherlands. The larvae, which feed on the root system of the plant, can be controlled by insect parasitic nematodes, Heterorhabditis. However, the presently available isolates of the nematode are ineffective at temperatures below 12-13°C, causing problems in black vine weevil control in open cultures. In this study, options to improve control by Heterorhabditis are explored, using a systems analytical approach. First, the nematode behavioural processes involved in host finding and control were studied and characterized. These processes are nematode movement, immobilization and remobilization near the soil surface, accumulation near an attractive insect (arrestment), penetration and aggregation of nematodes among insect hosts. The influence of temperature (9 and 20°C) and host species ( O . sulcatus or the more attractive and susceptible Galleria mellonella) on nematode behaviour was assessed to determine the contribution of these factors to control success. Knowledge of behavioural processes was integrated into a systems simulation model that relates the control success to the underlying behavioural processes. The model simulates movement of nematodes in space and time from the moment of application on a sand column until penetration into a host. The model for O . sulcatus at 9°C was most sensitive to changes in the parameters characterizing aggregation and arrestment. Parameters characterizing penetration, the proportion infectious nematodes and the relative penetration rate, had a moderate effect on model outcome. Options for improvement were evaluated by relating the sensitivity of the model to genetic and phenotypic variation found in the nematodes. The amount of variation was assessed by comparing behavioural traits between and within Heterorhabditis isolates. Aggregation and arrestment are host related and there is little variation in Heterorhabditis for these traits. There is phenotypic variation in the proportion infectious nematodes. The most promising option to enhance control of O . sulcatus by Heterorhabditis at low temperatures is, therefore, to improve production and storage conditions to increase and stabilize the proportion infectious nematodes
Box 34, Neg. No. 6439: F. J. Westerman
No full textThis black and white photograph features a portrait of F. J. Westerman - he is wearing a suit. F. J. Westerman ordered the photograph.https://scholars.fhsu.edu/stafford_county/5165/thumbnail.jp
Substituição de potássio por sódio na nutrição de plantas: I. alface (Lactuca sativa L.).
No full textO efeito de diferentes níveis de sódio e potássio e suas interações sobre a produção e a composição química da alface (Lactuca sativa, L.) cultivar Vanguard foram investigadas
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Real-Time Traffic Data Collection for Transportation Telematics
No full textCivil Engineering and Geoscience
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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