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991.
CHARLES G. SCALET 《The Journal of wildlife management》2007,71(6):1749-1752
Abstract: Over the last 35 years there has been a shift in university wildlife and fisheries academic programs away from management and toward an ecology or conservation ethos. These university changes have been in both research and education. A similar change has occurred in direction among state and federal natural resource agencies. However, the changes exhibited by both groups have not been to the same degree. I believe university academic programs are now scaled more to the ecology—conservation side, while agencies still average to the management side. This represents a disconnect because university academic programs conduct research for these agencies (and others) and also educate future agency employees and provide technical services to agencies. 相似文献
992.
Langerhans cells and indeterminate cells are immune macrophages of the epidermis and have Ia markers on their surface. Because of their position in the epidermis, they are subject to many environmental toxins like ultraviolet light. Also medications like cortisone applied topically to the skin could have important effects on these cells. We have used an anti-Ia serum and an indirect immunofluorescent technique to study Langerhans cells in epidermal sheets. We found that shortwave ultraviolet light (250–320 nm) and ultraviolet B (280–320nm) increased the density of Ia-bearing cells (Langerhans cells) in the skin. Psoralens and ultraviolet A (PUVA) (320–400 nm) depleted the skin of Ia-bearing cells, an effect which takes 2 weeks to produce but which persists for several weeks after stopping treatment. Triamcinolone acetonide administered topically or intraperitoneally also depletes the skin of Ia-bearing cells. These agents, light and steroids, either destroy the Ia-bearing cells or remove the Ia markers from the cellular surface. 相似文献
993.
Sounds of Learning: The Impact of Music Education is a research program designed to allow researchers to examine the roles of music education in the lives of school-aged children to expand the understanding of music's role in a quality education. The NAMM Foundation, the sponsoring organization, has provided more than $1,000,000 to fund research on the impact of music education on student achievement and success in school; all aspects of a child's growth and development; the uses and functions of music in daily life; and home, school, and community environments. Quality research about the role and impact of music education conducted by experienced researchers who publish in rigorous, peer-reviewed, scientific research journals plays a vital role in moving a public policy agenda forward to achieve expanded access to music education for all children. The goal is that this research will inform policy debates and development to achieve policies that support opportunities for every child to experience the power and benefits of learning music. 相似文献
994.
Ruth Reeves 《Arts Education Policy Review》2013,114(1):13-20
This article reviews the political and empirical record within music education surrounding the Goals 2000: Educate America Act and reports a new study evaluating the effects of the law on music and arts education policies in U.S. high schools. School-level data (N = 670 schools) from the National Education Longitudinal Study of 1988 and the Education Longitudinal Study of 2002 were independently pooled to estimate the effects of Goals 2000 on the number of unique music courses high schools offered, the probability that schools would enforce a local arts graduation requirement, and the number of arts courses required for graduation. Results showed no effect on the number of unique music courses offered. However, for schools in states that prior to Goals 2000 had no arts education mandate or had a flexible arts education mandate, Goals 2000 significantly increased the probability of schools requiring the arts, as well as the number of arts credits required for graduation. The article concludes with implications for the arts in the current Common Core Standards movement. 相似文献
995.
M.G. Bulmer 《Journal of theoretical biology》1984,106(4):529-535
Gillespie (1974,1975) has shown that selection will tend to minimize variance in offspring number. It is shown that this effect is due to selection maximizing the average number of surviving offspring when there is density-dependent survival, and that it is unnecessary to invoke principles such as minimizing the variability of fitness (Real, 1980). The effect of this principle of selecting for laying several small clutches rather than one large clutch when there is predation on whole clutches is investigated. It is found that the selection pressure is weak, contrary to the conclusion of Rubenstein (1982), and is unlikely to be of evolutionary importance. 相似文献
996.
Ronald P. Kos Jr. 《Arts Education Policy Review》2018,119(4):204-216
Critical approaches to policy analysis, although common in general education, are rare in arts education literature. By adopting critical approaches, researchers can produce scholarship that will be transformative for policies that impact arts education and for the profession as a whole. In this article, I present a framework that allows researchers to incorporate critical theory into policy analysis. This ideological work can expose sources of power and help reveal the ways in which the targets of policy are complicit in their own domination. Adopting this framework, I examine the well-rounded education provision of the Every Student Succeeds Act of 2015 to better understand the policy's origins, its development, and the potential implications for music education. 相似文献
997.
PurposeThe electron or photon beams might be used for treatment of tumors. Each beam has its own advantage and disadvantages. Combo beam can increase the advantages. No investigation has been performed for producing simultaneous mixed electron and photon beam. In current study a device has been added to the Medical Linac to produce a mixed photon–electron beam.MethodsFirstly a Varian 2300CD head was simulated by MCNP Monte Carlo Code. Two sets of perforated lead sheets with 1 and 2 mm thickness and 0.2, 0.3, and 0.5 cm punches then placed at the top of the applicator holder tray. This layer produces bremsstrahlung x-ray upon impinging fraction electrons on it. The remaining fraction of electrons passes through the holes. The simulation was performed for 10 × 10, 6 × 6, and 4 × 4 cm2 field size.ResultsFor 10 × 10 cm2 field size, among the punched targets, the largest penumbra difference between the depth of 1 and 7 cm was 72%. This difference for photon and electron beams were 31% and 325% respectively. A maximum of 39% photon percentage was produced by 2 mm target with 0.2 cm holes diameter layer. The minimum surface dose value was 4% lesser than pure electron beam. For small fields, unlike the pure electron beam, the PDD, penumbra, and flatness variations were negligible.ConclusionsThe advantages of mixing the electron and photon beam is reduction of pure electron's penumbra dependency with the depth, especially for small fields, also decreasing of dramatic changes of PDD curve with irradiation field size. 相似文献
998.
999.
Allelic allotype inclusion and exclusion among rabbit Ig-bearing lymphocytes of peripheral blood and lymphoid organs 总被引:1,自引:0,他引:1
Mononuclear cells isolated from peripheral blood, appendix, sacculus rotundus, mesenteric lymph nodes, and spleen of b4b5 heterozygous rabbits were examined for surface Ig allotypes of the b locus. Ig allotype-bearing cells were detected as cells binding erythrocytes or bacteria coated with monospecific anti-b4 or anti-b5 antibody (Ab). Rosetting the cells with Ab-coated erythrocytes indicated that many peripheral blood lymphocytes, but relatively few appendix cells, bore both the b4 and b5 allotypes. Lymphocytes bearing both the b4 and b5 allotypes were also detected by incubating the cells with a mixture of Escherichia coli coated with anti-b4 Ab and Gaffkya tetragena coated with anti-b5 Ab. The percentage of Ig-positive lymphocytes binding both bacteria was 22–31% in the peripheral blood, 4–6% in the appendix, 3–5% in the sacculus rotundus, 4–10% in the mesenteric lymph nodes, and 5% in the spleen. Thus, the percentage of double-bearing lymphocytes was higher in the blood than in the appendix, sacculus rotundus, mesenteric lymph nodes, or spleen. The b4b5-bearing cells in the blood were not cells with adsorbed cytophilic Ab, since these cells still bore both the b4 and b5 allotypes after pronase digestion and Ig regeneration. These double-bearing lymphocytes, i.e., cells exhibiting allelic allotype inclusion, are probably less differentiated cells. 相似文献
1000.
CHRISTIE W. KIEFER 《American anthropologist》1970,72(1):66-75
The Japanese "examination hell" phenomenon is viewed as a series of crisis rites through which the child passes from family-centered to peer group-centered values in a "particularistic" society. It is held that this model has greater explanatory power than the "minimization of competition" model proposed by others and that it also helps to explain the phenomenon of student radicalism and centrifugal relationships in middle-class communities. 相似文献