75,192 research outputs found
\u3ci\u3eTomicus Piniperda\u3c/i\u3e (Coleoptera: Scolytidae) Reproduction and Behavior on Scotch Pine Christmas Trees Taken Indoors
Tomicus piniperda, the pine shoot beetle, is an exotic insect that was first found in North America in 1992. A federal quarantine currently restricts movement of pine products, including Christmas trees, from infested to uninfested counties. We conducted a study to determine if T. piniperda would re- produce in Christmas trees that were cut and taken indoors during the Christmas season. Twelve Scotch pine, Pinus sylvestris, Christmas trees infested with overwintering T. piniperda beetles were cut in Indiana in early December 1993 and taken to Michigan. Four trees were dissected immediately, while the other 8 trees were taken indoors, placed in tree stands, and watered regularly. After 4 weeks indoors, 4 trees were dissected, and the other 4 were placed outdoors in Michigan for 7 weeks. Upon dissection, all overwintering sites occurred along the lower trunk within the first 40 em of the soil line; 81% were found within 10 em of the soil line. Adults collected from the 4 trees dissected in December produced viable progeny adults when placed on Scotch pine logs in the laboratory. Overwintering beetles became active and laid eggs in 4 of the 8 trees that had been taken indoors. All adults and progeny found in the 4 trees that had been placed outdoors for 7 weeks during cold January and February temperatures were dead. Overall, T. piniperda can become active and breed in Christmas trees that are cut and taken indoors in December. Tomicus piniperda survival in trees that are discarded outdoors at the end of the Christmas season will depend largely on the prevailing temperatures
Seasonal Shoot-Feeding by \u3ci\u3eTomicus Piniperda\u3c/i\u3e (Coleoptera: Scolytidae) in Michigan
Seasonal shoot-feeding by Tomicus piniperda (L.) was monitored at 2Â week intervals on 15 Scotch pine, Pinus sylvestris L., trees from 8 April through 16 November 1994 in southern Michigan. All shoots that showed evidence of T. piniperda attack were removed every two weeks. In 1994, initial spring flight of T. piniperda began on 22 March. At least two live T. piniperda adults were found on the 15 trees on each sampling date from 8 April through 1 November 1994. In addition, at least one freshly attacked, beetle- free shoot was found on each sampling date except for 1 November. The greatest numbers of newly attacked shoots, with or without adults present, were found from mid-June through mid-August. All adults found in April and May were likely parent adults, while those from June onward were primarily brood adults. Therefore, at all times of the year, live T. piniperda adults can be found on live pine trees, either feeding in the shoots or overwintering at the base of the trunk. Implications of these findings are provided in light of the US federal quarantine on T. piniperda
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Household wealth and adolescents' social-emotional functioning in schools.
This study attempts a two-part shift in educational research narrowly fixated on the socioeconomic determinants of student test-score performance. First, we focus on variations in how to measure wealth. Second, we move beyond achievement and focus on the wealth determinants of adolescents' social-emotional competencies. Using data from a nationally-representative sample of US eighth graders, we find that the correlation between wealth and social-emotional competencies varies according to how the partitions among the upper class, the middle and working classes, and the poor are defined. By emphasizing wealth in the production of classed social-emotional competencies not captured by test scores, our findings suggest that the growth of household wealth has a more salient effect for lower- and middle-class adolescents than the highest class which appears to have the least to gain, in terms of social-emotional competencies, from an increase in household wealth
Occasional Publications on Northern Life, No. 04
The need to exchange information on research in reindeer and
caribou diseases became apparent to investigators attending the Second
International Reindeer/Caribou Symposium in Roros, Norway, in 1979.
Initially, bibliographies were to be exchanged by being submitted to and
subsequently distributed by workers at the University of Alaska. When
the bibliographies were submitted, it seemed sensible to computerize the
lists to facilitate searches for specific information in the future. An
apparently simple task became amazingly complex. This is the resultant collection of publications by
reindeer/caribou disease researchers. Because researchers in wildlife
diseases tend to work on more than one species or topic, out of interest
or necessity, a decision was made to include all of a person's
references rather than to limit them to strictly reindeer/caribou
diseases.
The authors hope this will provide a good basis for exchange of
information among all those interested in reindeer/caribou diseases
Quantum number dimensional scaling analysis for excited states of multielectron atoms
A new dimensional scaling method for the calculation of excited states of
multielectron atoms is introduced. By including the principle and orbital
quantum numbers in the dimension parameter, we obtain an energy expression for
excited states including high angular momentum states. The method is tested on
He, Li, and Be. We obtain good agreement with more orthodox quantum mechanical
treatments even in the zeroth order.Comment: Submitted to Physical Review A, 13 pages, 6 Table
Disruptant Effects of 4-Allylanisole and Verbenone on \u3ci\u3eTomicus Piniperda\u3c/i\u3e (Coleoptera: Scolytidae) Response to Baited Traps and Logs
We assessed the inhibitory effects of the host compound 4-allylanisole (release rates = 1 and 2 mg/d in 1994, and 1 and 10 mg/d in 2001) on the response of the pine shoot beetle, Tomicus piniperda (L.), adults to funnel traps baited with the attractant host compound α-pinene (release rate = 150 mg/d) in two pine Christmas tree plantations in Michigan in spring 1994 and two other plantations in spring 2001. In three of the four plantations, all doses of 4- allylanisole significantly reduced T. piniperda attraction to α-pinene-baited traps by 46 to 76%. We also tested the inhibitory effect of the antiaggregation pheromone verbenone (release rates = 2 and 4 mg/d) on T. piniperda attack density on pine bolts (average bolt length was 62 cm and diameter was 19 cm) at three sites (two pine forest stands and one Christmas tree plantation) in Michigan in 1994. Verbenone significantly reduced T. piniperda attack density by 37 to 60% at the two pine stands, but not at the Christmas tree plantation
Composite micromechanical modeling using the boundary element method
The use of the boundary element method for analyzing composite micromechanical behavior is demonstrated. Stress-strain, heat conduction, and thermal expansion analyses are conducted using the boundary element computer code BEST-CMS, and the results obtained are compared to experimental observations, analytical calculations, and finite element analyses. For each of the analysis types, the boundary element results agree reasonably well with the results from the other methodologies, with explainable discrepancies. Overall, the boundary element method shows promise in providing an alternative method to analyze composite micromechanical behavior
Review of the Returns to ACIAR's Bilateral R&D Investments
Research and Development/Tech Change/Emerging Technologies,
Digital enhancement of flow field images
Most photographs of experimentally generated fluid flow fields have inherently poor photographic quality, specifically low contrast. Thus, there is a need to establish a process for quickly and accurately enhancing these photographs to provide improved versions for physical interpretation, analysis, and publication. A sequence of digital image processing techniques which have been demonstrated to effectively enhance such photographs is described
Does family structure affect children's educational outcomes?
In this paper we examine the effect of family structure on childrenâs educational outcomes by exploiting the sibling structure in the NLSY and NLSY-Child to control for unobserved heterogeneity across families and individuals. We also compare outcomes for children within the same familyâstepchildren with their half-siblings in the same blended family who are the biological children of both parents. Using panel data methods to control for unobserved heterogeneity across families, we find that family structure effects are statistically insignificant. Finally, comparing half-siblings in our data, we find no difference in educational outcomes as a function of family structure. Our empirical results are consistent with at least two interpretations. First, they can be interpreted as evidence that estimates of family structure effects reflect selection rather than causation. Second, they can be interpreted as evidence that the presence of stepchildren disrupts families.Child care ; Demography ; Education ; Human capital
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