Science, technology, engineering, and mathematics (STEM) graduate students are often encouraged to maximize their engagement with supervised research and minimize teaching obligations. However, the process of teaching students engaged in inquiry provides practice in the application of important research skills. Using a performance rubric, we compared the quality of methodological skills demonstrated in written research proposals for two groups of early career graduate students (those with both teaching and research responsibilities and those with only research responsibilities) at the beginning and end of an academic year. After statistically controlling for preexisting differences between groups, students who both taught and conducted research demonstrate significantly greater improvement in their abilities to generate testable hypotheses and design valid experiments. These results indicate that teaching experience can contribute substantially to the improvement of essential research skills. 相似文献
Research on environmental justice issues, particularly unequal park distribution and quality, has found that communities’ minority density and socioeconomic status (SES) are often correlated with disparate park qualities. However, most studies of spatial relationships between park quality and socioeconomic factors employ simple statistical analyses, which do not account for potential spatial autocorrelations and their effects on validity.
Objectives
This study determines whether the distribution of park quality is spatially autocorrelated and assesses the associations among multiple indicators of environmental justice and both separate park features and overall park quality.
Methods
This study evaluates spatial relationships between park quality and multiple environmental justice indicators in Cache County, Utah following the spatial regression process conducted in R programming language. Both overall park quality and separate feature qualities were audited by the PARK (Parks, Activity, and Recreation among Kids) tool. Environmental justice indicators included minority density, poverty, unemployment, low-education, renter rate, and yard size.
Results
Results illustrate a spatial autocorrelation existing in park quality distribution, detecting the dependence of the variable for quantitative research. They also show significant correlations between park quality and environmental justice indicators.
Conclusions
The study’s spatial regression model is a model for analyzing the spatial data and avoids the autocorrelation which is overlooked by the normal statistical approaches. Also, variances of park quality can be accounted for by different environmental justice indicators, such as minority density, poverty, and yard size. This disclosure of disparate public resource quality treatment among different groups of individuals could inspire policy makers and city planners to correct these disparities.
SUMMARY Insecticidal dipping fluid emulsions, mixed in vitro in dam water containing suspended clay particles and 1% w/v zinc sulphate, were analysed to determine rates of settling of diazinon, cyhalothrin and cypermethrin. Fifteen minutes after mixing, the concentration of the insecticides 5 cm below the surface had declined by 72.5%, 72.8% and 89.4%, respectively. On remixing, the concentration of insecticide in suspension was close to or greater than the initial concentration. In 2 trials, lice were eradicated from sheep showered with dip wash mixed in cloudy dam water to which 1% w/v of zinc sulphate was added. In 12 flock treatments in which 1000 to 2000 sheep were dipped with added zinc sulphate, the concentration of insecticide remained above the minimum lethal for susceptible strains of lice. However, lice were still present 6 months later in 8 of these flocks. When zinc sulphate is added to dip wash, agitation is needed to maintain the insecticide in suspension. 相似文献
The aim of this study was to evaluate three different cloning strategies in the domestic cat (Felis silvestris) and to use the most efficient to generate wild felid embryos by interspecific cloning (iSCNT) using Bengal (a hybrid formed by the cross of Felis silvestris and Prionailurus bengalensis) and tiger (Panthera tigris) donor cells. In experiment 1, zona‐free (ZP‐free) cloning resulted in higher fusion and expanded blastocyst rates with respect to zona included cloning techniques that involved fusion or injection of the donor cell. In experiment 2, ZP‐free iSCNT and embryo aggregation (2X) were assessed. Division velocity and blastocyst rates were increased by embryo aggregation in the three species. Despite fewer tiger embryos than Bengal and cat embryos reached the blastocyst stage, Tiger 2X group increased the percentage of blastocysts with respect to Tiger 1X group (3.2% vs 12.1%, respectively). Moreover, blastocyst cell number was almost duplicated in aggregated embryos with respect to non‐aggregated ones within Bengal and tiger groups (278.3 ± 61.9 vs 516.8 ± 103.6 for Bengal 1X and Bengal 2X groups, respectively; 41 vs 220 ± 60 for Tiger 1X and Tiger 2X groups, respectively). OCT4 analysis also revealed that tiger blastocysts had higher proportion of OCT4‐positive cells with respect to Bengal blastocysts and cat intracytoplasmic sperm injection blastocysts. In conclusion, ZP‐free cloning has improved the quality of cat embryos with respect to the other cloning techniques evaluated and was successfully applied in iSCNT complemented with embryo aggregation. 相似文献
Pressures being exerted on the ocean ecosystems through overfishing, pollution, and environmental and climate change are increasing. Six core principles are proposed to guide governance and use of ocean resources and to promote sustainability. Examples of governance structures that embody these principles are given. 相似文献
The Mars Global Surveyor (MGS) z-axis accelerometer has obtained over 200 vertical structures of thermospheric density, temperature, and pressure, ranging from 110 to 170 kilometers, compared to only three previous such vertical structures. In November 1997, a regional dust storm in the Southern Hemisphere triggered an unexpectedly large thermospheric response at mid-northern latitudes, increasing the altitude of thermospheric pressure surfaces there by as much as 8 kilometers and indicating a strong global thermospheric response to a regional dust storm. Throughout the MGS mission, thermospheric density bulges have been detected on opposite sides of the planet near 90 degreesE and 90 degreesW, in the vicinity of maximum terrain heights. This wave 2 pattern may be caused by topographically-forced planetary waves propagating up from the lower atmosphere. 相似文献
Summary The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 ± 6.9 min with TK and 82.8 ± 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep. 相似文献
The age and/or physical condition of mulesing wounds had a significant effect on both the oviposition response of L. cuprina and the ability of the wound to support a strike. Up to 48 h after mulesing, untreated wounds elicited a strong oviposition response in contrast with chemically treated wounds, although subsequent larval development was negligible. Seven to 9-day-old wounds, however, regardless of the wound treatment, were highly attractive oviposition sites, which subsequently developed into strikes; the D3 formulation of Defiance*S, however, significantly depressed strike development and shows promise as a mules wound treatment. A marked improvement in the wound healing 14 to 16 d after mulesing coincided with a significant decrease in oviposition. Only those sheep whose wound scabs remained broken, exposing pus and raw tissue, attracted oviposition; subsequent development of the eggs into strikes was negligible. 相似文献