224 research outputs found

    DEVELOPING ALTERNATIVE PRACTICES FOR MANAGEMENT OF FLEA BEETLES ATTACKING EGGPLANT AND LEAFY BRASSICACEOUS GREENS

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    Flea beetles are a challenging pest for many producers of vegetable crops in Kentucky. Chewing numerous small holes in the leaves of their host plants, high flea beetle populations can quickly overwhelm unestablished crops. I tested the efficacy of several alternatives to insecticides within brassicaceous leafy greens and eggplant. Four field trials in 2019 and 2020 compared essential oil sprays, the woven-mesh row cover ProtekNet, the spunbonded row cover Agribon, and reflective silver mulch to an untreated control, a conventional insecticide rotation of dinotefuran and pyrethroids, and an organic insecticide rotation of spinosad and pyrethrins. The silver reflective mulch was used within the eggplant trials and was compared against black plastic mulch. This thesis demonstrates the efficacy of row covers in limiting damage by flea beetles and improving marketable yield in brassicaceous greens and eggplant. On the contrary, other new alternatives, including silver plastic mulches and the essential oils from thyme, rosemary, eucalyptus, neem, peppermint, and geranium showed no better control than the untreated control, and in some cases, reduced yield by harming plants. For this reason, further research and outreach should focus on the life expectancy of row covers and expanding their adoption

    Holocaust Remembrance Service 1994

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    [A Holocaust remembrance service] co-sponsored by Campus Ministry, the office of the Academic Vice President and the Jewish Forum to commemorate 1994 Holocaust Remembrance Day.https://digitalcommons.fairfield.edu/bennettcenter-posters/1181/thumbnail.jp

    Development of flashlamp-pumped Q-switched Ho:Tm:Cr:YAG lasers for mid-infrared LIDAR application

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    A flashlamp-pumped 2.1 micron Ho:Tm:Cr:YAG laser was studied for both normal mode and Q-switched operations under a wide variety of experimental conditions in order to optimize performance. Laser output energy, slope efficiency, threshold and pulselength were determined as a function of operating temperature, output mirror reflectivity, input electrical energy and Q-switch opening time. The measured normal-mode laser thresholds of a Ho(3+) (0.45 atomic percent):Tm(3+) (2.5 atomic percent):Cr(3+) (0.8 atomic percent):YAG crystal ranged form 26 to 50 J between 120 and 200 K with slope efficiencies up to 0.36 percent with a 60 percent reflective output mirror. Under Q-switched operation the slope efficiency was 90 percent of the normal-mode result. Development of solid state lasers with Ho(3+), Tm(3+) and/or Er(3+) doped crystals has been pursued by NASA for eye-dafe mid-infrared LIDAR (light detection and ranging) application. As a part of the project, the authors have been working on evaluating Ho(3+):Tm(3+):Cr(3+):YAG crystals for normal-mode and Q-switched 2.1 micron laser operations in order to determine an optimum Tm(3+) concentration under flashlamp pumping conditions. Lasing properties of the Ho(3+) in the mid-infrared region have been studied by many research groups since the early 1960's. However, the technology of those lasers is still premature for lidar application. In order to overcome the inefficiency related to narrow absorption bands of the Ho(3+), Tm(3+) and Er(3+), the erbium has been replaced by chromium. The improvement in flashlamp-pumped Ho(3+) laser efficiency has been demonstrated recently by several research groups by utilizing the broad absorption spectrum of Cr(3+) which covers the flashlamp's emission spectrum. Efficient energy transfer to the Tm(3+) and then the Ho(3+) occurs subsequently. It is known that high Tm(3+) concentration and low Ho(3+) concentration are preferred to achieve a quantum efficiency approaching two and to avoid large reabsorption losses. However, determination of the optimum Tm(3+) concentration required to ensure efficient energy transfer from Cr(3+) to Tm(3+) and from Tm(3+) to Ho(3+) has not been made in the Ho:Tm:CR:YAG crystal. The results obtained so far are given

    The role of achievement, gender, SES, location and policy in explaining the Indigenous gap in high-school completion

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    Internationally, there is a gap in high-school completion rates for Indigenous and non-Indigenous students. In Australia, gap estimates are commonly based on lag indicators, precluding examination of underlying mechanisms. Using two longitudinal representative samples of Australian youth, we explored differences in high-school completion between Australian Indigenous and non-Indigenous rates, and whether the gap varies for students of similar academic ability. Using an intersectional approach, we show the Indigenous gap is significant, is mostly a function of differences in academic achievement, but varies by socioeconomic status (SES) and location. Specifically, high SES and living in urban settings are protective factors for non-Indigenous students, but not for Indigenous students. Conversely, rural and poor non-Indigenous students appeared to have dropout rates as large or even larger than similarly poor and rural Indigenous youth. Overall, the results suggest the need for a more nuanced perspective on ‘Indigenous gaps’ in educational attainment

    Newton’s Unfinished Business: Uncovering the Hidden Powers of Eleven in Pascal’s Triangle

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    Sir Isaac Newton once observed that the first five rows of Pascal’s Triangle, when concatenated, yield the corresponding powers of eleven. He claimed without proof that subsequent rows also generate powers of eleven. Was he correct? While not all rows can simply be concatenated, the powers of eleven can still be easily derived from each. We have uncovered an algorithm the supports Newton’s claim and will prove its validity for all rows of the Triangle

    Newton’s Unfinished Business: Uncovering the Hidden Powers of Eleven in Pascal’s Triangle

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    Sir Isaac Newton once observed that the first five rows of Pascal’s Triangle, when concatenated, yield the corresponding powers of eleven. He claimed without proof that subsequent rows also generate powers of eleven. Was he correct? While not all rows can simply be concatenated, the powers of eleven can still be easily derived from each. We have uncovered an algorithm the supports Newton’s claim and will prove its validity for all rows of the Triangle

    Discrimination as a frame-of-reference effect in overlapping friendship communities of ethnically diverse youth

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    Objectives: To what extent is the frame of reference of overlapping friendship communities important for young people’s feelings of discrimination and subjective wellbeing? That is, do youth feel better or worse to the extent that they feel less or more discrimination than their friends? Methods: Participants (N=898; Mage=14.13; SDage=3.37; 46% females; 46% Whites; 20% Indigenous; 34% other minorities) were high school students of three ethnically diverse, low SES public schools in New South Wales, Australia. Cross-sectional data were collected to measure felt discrimination, mental health, subjective wellbeing, social support and nominations of close friends. A state-of-the-art method of clustering links was used to identify overlapping friendship communities, and multiple membership multilevel models were run to examine whether community level discrimination moderated the link between individual level discrimination and wellbeing. Results: When the community level discrimination was low, there was no wellbeing related cost or benefit of individual level discrimination. But when the community level discrimination was high, individuals in those communities who themselves felt low discrimination had better wellbeing than individuals who themselves felt high discrimination. Conclusions: We provide evidence for a frame-ofreference effect involving discrimination. Individuals’ relative standing in their friendship communities with high group-level discrimination reliably predicted the individuals’ wellbeing levels, regardless of ethnicity. The results highlight the importance of identifying overlapping friendship communities for understanding the dynamics of discrimination and wellbeing of ethnically diverse youth

    A Nonparametric Estimation of the Local Zipf Exponent for all US Cities

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    In this short paper we apply the methodology proposed by Ioannides and Overman (2003) to estimate a local Zipf exponent using data for the entire twentieth century of the complete distribution of cities (incorporated places) without any size restrictions in the US. The results reject Zipf’s Law from a long term perspective, as the estimated values are close to zero. However, decade by decade we find evidence in favour of Zipf’s Law. We also see how periods in which the Zipf exponent grows with city size are interspersed with others in which the relationship between the exponent and city shares is negative

    The Impact of Plant Essential Oils and Fine Mesh Row Covers on Flea Beetle (Chrysomelidae) Management in Brassicaceous Greens Production

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    Brassicaceous leafy greens are an important crop for small growers but are difficult to produce due to damage by flea beetles. Flea beetles are problematic for growers as they chew many small holes through leaves rendering produce unmarketable. We tested the efficacy of several essential oils, the woven-mesh row cover ProtekNet, and the spunbonded row cover Agribon, compared to organic and conventional insecticides and no spray controls in the spring and fall of 2019. We found that the two row cover treatments (Agribon and ProtekNet) provided the best control of flea beetles and associated damage. Thyme oil was highly phytotoxic and killed the crop entirely and rosemary and neem essential oils caused mild phytotoxic burns. Organic insecticides rarely performed better than the no spray control. While conventional insecticides controlled most flea beetles, the crop was often still too highly damaged to sell. The results of our study suggest row covers offer producers an effective method of flea beetle control that reduces their dependence on insecticides for conventional and organic production

    A randomized trial of artemether-lumefantrine versus mefloquine-artesunate for the treatment of uncomplicated multi-drug resistant Plasmodium falciparum on the western border of Thailand

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    BACKGROUND: The use of antimalarial drug combinations with artemisinin derivatives is recommended to overcome drug resistance in Plasmodium falciparum. The fixed combination of oral artemether-lumefantrine, an artemisinin combination therapy (ACT) is highly effective and well tolerated. It is the only registered fixed combination containing an artemisinin. The trial presented here was conducted to monitor the efficacy of the six-dose regimen of artemether-lumefantrine (ALN) in an area of multi-drug resistance, along the Thai-Myanmar border. METHODS: The trial was an open-label, two-arm, randomized study comparing artemether-lumefantrine and mefloquine-artesunate for the treatment of uncomplicated falciparum malaria with 42 days of follow up. Parasite genotyping by polymerase chain reaction (PCR) was used to distinguish recrudescent from newly acquired P. falciparum infections. The PCR adjusted cure rates were evaluated by survival analysis. RESULTS: In 2001–2002 a total of 490 patients with slide confirmed uncomplicated P. falciparum malaria were randomly assigned to receive artemether-lumefantrine (n = 245) or artesunate and mefloquine (n = 245) and were followed for 42 days. All patients had rapid initial clinical and parasitological responses. In both groups, the PCR adjusted cure rates by day 42 were high: 98.8% (95% CI 96.4, 99.6%) for artemether-lumefantrine and 96.3% (95% CI 93.1, 98.0%) for artesunate-mefloquine. Both regimens were very well tolerated with no serious adverse events observed attributable to either combination. CONCLUSION: Overall, this study confirms that these two artemisinin-based combinations remain highly effective and result in equivalent therapeutic responses in the treatment of highly drug-resistant falciparum malaria
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