770 research outputs found

    Nitrate and herbicide leaching as affected by conservation tillage

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    Conservation tillage is widely promoted because it has been demonstrated to help reduce erosion. But soil conservation concerns must be balanced against the possibility that such tillage may allow greater chemical leaching (removal of fertilizers and pesticides from the root zone of the soil by downward-percolating water), thus degrading water quality

    Instructional Supervision: Is it Culturally Responsive? A Textbook Analysis

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    The purpose of this study was to determine whether and to what degree textbooks are preparing aspiring principals as culturally responsive instructional supervisors. After evaluating multiple textbooks against selection criteria, SuperVision and Instructional Leadership: A Developmental Approach, was identified as the study’s unit of analysis. An audit of the subject index was conducted to answer: How are culturally responsive instructional supervision competencies addressed in this leading supervision textbook? Findings revealed content related to cultural responsiveness was concentrated in a chapter at the back of the textbook and the clinical supervision cycle, a powerful means of changing instructional practices (Gordon, 2016; Grissom et al., 2021), was all but devoid of references to culture. As future and current school leaders prepare to supervise a still predominantly White teacher population, with the aim of instructional improvement for an even more diverse student population, the need for supervision that is culturally centered is imperative

    Assessment of the wintering area of Red Knots in Maranhão, northern Brazil, in February 2005

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    To assess population size and the conservation status of the Red Knot Calidris canutus rufa population in Maranhão, N Brazil, an aerial census and field studies were conducted in February 2005. The aerial count showed a population of 7,575 Knots, which is down about 600 from a previous census in the 1980s. However, the count for all shorebird species combined was only 24,000 compared to 198,600 in the 1980s, paralleling a world-wide trend of population decline in shorebirds. Resightings of colour-banded knots confirmed that this is a separate population from the larger wintering population in Tierra del Fuego. All species of shorebirds captured in Maranhão were found to be infested with feather lice and mites. Body masses of knots in Maranhão were significantly lower than in Tierra del Fuego, and about half the birds were below the hypothesized fat-free mass of the species. Blood and feather samples were taken from 38 Knots for subsequent assessment of virus loads, and for detecting sites where primary feather moult had occurred. This will enable us to establish whether significant mortality is associated with pathogen loads and the energetic demands of delayed moulting. The small size of the Maranhão population and the loss of another 13,000 knots this winter from the Tierra del Fuego population means that both are now endangered. Brochures on the need for Red Knot conservation were designed and printed, and have been circulated among fishing communities and school classes in Maranhão.Fil: Baker,Allan J.. Royal Ontario Museum; CanadáFil: González, Patricia M.. Fundación Inalafquen; ArgentinaFil: Serrano, Ines L.. CEMAVE, Centro Nacional de Pesquisa para Conservação das Aves Silvestres; BrasilFil: Júnior, Wallace R. T.. CEMAVE, Centro Nacional de Pesquisa para Conservação das Aves Silvestres; BrasilFil: Efe, Marcio A.. Universidade Federal de Alagoas; BrasilFil: Rice, Susan. Eastern Shore of Virginia National Wildlife Refuge; Estados UnidosFil: D'amico, Veronica Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Rocha, Marcia C.. Belém, Pará; BrasilFil: Echave, María Eugenia. Fundación Inalafquen; Argentin

    Predictors of Achievement When Virtual Manipulatives are Used for Mathematics Instruction

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    The purpose of this study was to determine variables that predict performance when virtual manipulatives are used for mathematics instruction. This study included the following quasi-experimental design features: 1) a large number of students (N=350); 2) within-class random-assignment to treatment groups; 3) retention effects measured by post-test and delayed post-test; 4) fidelity of instructional treatments documented through observations; and, 5) instrument development for the unit of study. This design was used to determine variables that predict student performance on tests of fraction knowledge for third- and fourth-grade students in two treatment groups: classroom instruction using texts and physical manipulatives (CI), and computer lab instruction using virtual fraction applets (VM). The Pre-test, Post-test 1, and Post-test 2 measured learning and retention of fraction concepts. Observation ethograms documented representation use. The results revealed that fewer demographic predictors of student performance (e.g., socio-economic status, English language learner status, and gender) exist during fraction instruction when virtual manipulatives were used. When instructors used virtual manipulatives, there was an equalizing effect on achievement in third and fourth grade classrooms, in that fewer demographic factors were influential for VM groups compared to CI groups

    An Observational Study of the "Interstate 5" Dust Storm Case

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    On 29 November 1991 a series of collisions involving 164 vehicles occurred on Interstate 5 in the San Joaquin Valley in California in a dust storm that reduced visibility to near zero. The accompanying high surface winds are hypothesized to result from intense upper-trophospheric downward motion that led to the formation of a strong upper front and tropopause fold and that transported high momentum air downward to midlevels where boundary layer processed could then mix it to the surface. The objectives of the research presented in this paper are to document the event, to provide support for the hypothesis that both upper-level and boundary layer processes were important, and to determine the structure of the mesoscale circulations in this case for future use in evaluating the navy's mesoscale data assimilation system..

    Proof of concept of a personalized genetic risk tool to promote smoking cessation:High acceptability and reduced cigarette smoking

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    Relatively little is known about the possible effects of personalized genetic risk information on smoking, the leading preventable cause of morbidity and mortality. We examined the acceptability and potential behavior change associated with a personalized genetically-informed risk tool (RiskProfile) among current smokers. Current smokers (n=108) were enrolled in a pre-post study with three visits. At Visit 1, participants completed a baseline assessment and genetic testing via 23andMe. Participants’ raw genetic data (CHRNA5 variants) and smoking heaviness were used to create a tailored RiskProfile tool that communicated personalized risks of smoking-related diseases and evidence-based recommendations to promote cessation. Participants received their personalized RiskProfile intervention at Visit 2, approximately 6 weeks later. Visit 3 involved a telephone-based follow-up assessment 30 days after intervention. Of enrolled participants, 83% were retained across the three visits. Immediately following intervention, acceptability of RiskProfile was high (M=4.4; SD=0.6 on scale of 1 to 5); at 30-day follow-up, 89% of participants demonstrated accurate recall of key intervention messages. In the full analysis set of this single-arm trial, cigarettes smoked per day decreased from intervention to 30-day follow-up [11.3 vs. 9.8, difference=1.5, 95% CI (0.6—2.4), p=.001]. A personalized genetically-informed risk tool was found to be highly acceptable and associated with a reduction in smoking, although the absence of a control group must be addressed in future research. This study demonstrates proof of concept for translating key basic science findings into a genetically-informed risk tool that was used to promote progress toward smoking cessation

    Genetic isolation in an endemic African habitat specialist

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    The Chestnut-banded Plover Charadrius pallidus is a Near-Threatened shorebird species endemic to mainland Africa. We examined levels of genetic differentiation between its two morphologically and geographically distinct subspecies, C. p. pallidus in southern Africa (population size 11 000–16 000) and C. p. venustus in eastern Africa (population size 6500). In contrast to other plover species that maintain genetic connectivity over thousands of kilometres across continental Africa, we found profound genetic differences between remote sampling sites. Phylogenetic network analysis based on four nuclear and two mitochondrial gene regions, and population genetic structure analyses based on 11 microsatellite loci, indicated strong genetic divergence, with 2.36% mitochondrial sequence divergence between individuals sampled in Namibia (southern Africa) and those of Kenya and Tanzania (eastern Africa). This distinction between southern and eastern African populations was also supported by highly distinct genetic clusters based on microsatellite markers (global FST = 0.309, math formula = 0.510, D = 0.182). Behavioural factors that may promote genetic differentiation in this species include habitat specialization, monogamous mating behaviour and sedentariness. Reliance on an extremely small number of saline lakes for breeding and limited dispersal between populations are likely to promote reproductive and genetic isolation between eastern and southern Africa. We suggest that the two Chestnut-banded Plover subspecies may warrant elevation to full species status. To assess this distinction fully, additional sample collection will be needed, with analysis of genetic and phenotypic traits from across the species’ entire breeding range

    Space Flight Qualification on a Multi-Fiber Ribbon Cable and Array Connector Assembly

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    NASA's Goddard Space Flight Center (GSFC) cooperatively with Sandia National Laboratories completed a series of tests on three separate configurations of multi-fiber ribbon cable and MTP connector assemblies. These tests simulate the aging process of components during launch and long-term space environmental exposure. The multi-fiber ribbon cable assembly was constructed of non-outgassing materials, with radiation-hardened, graded index 100/140-micron optical fiber. The results of this characterization presented here include vibration testing, thermal vacuum monitoring, and extended radiation exposure testing data
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