37 research outputs found

    Deceleration and trapping of heavy diatomic molecules using a ring-decelerator

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    We present an analysis of the deceleration and trapping of heavy diatomic molecules in low-field seeking states by a moving electric potential. This moving potential is created by a 'ring-decelerator', which consists of a series of ring-shaped electrodes to which oscillating high voltages are applied. Particle trajectory simulations have been used to analyze the deceleration and trapping efficiency for a group of molecules that is of special interest for precision measurements of fundamental discrete symmetries. For the typical case of the SrF molecule in the (N,M) = (2, 0) state, the ring-decelerator is shown to outperform traditional and alternate-gradient Stark decelerators by at least an order of magnitude. If further cooled by a stage of laser cooling, the decelerated molecules allow for a sensitivity gain in a parity violation measurement, compared to a cryogenic molecular beam experiment, of almost two orders of magnitude

    Values and attitudes toward social and environmental accountability: A study of MBA students.

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    NoEfforts to promote corporate social and environmental accountability (SEA) should be informed by an understanding of stakeholders' attitudes toward enhanced accountability standards. However, little is known about current attitudes on this subject, or the determinants of these attitudes. To address this issue, this study examines the relationship between personal values and support for social and environmental accountability for a sample of experienced MBA students. Exploratory factor analysis of the items comprising our measure of support for SEA revealed two distinct factors: (1) endorsement of the general proposition that corporations and executives should be held accountable for the social and environmental impacts of their actions; and (2) agreement that the government should adopt and enforce formal SEA standards. Our findings indicate that the universalism value type is positively associated with general support for SEA, but not with support for government enforcement of accountability standards. In addition, we found that gender has a significant impact on support for government enforcement of SEA standards

    Allelopathic effect of endemic South American Bothriochloa species (Poaceae: Andropogoneae)

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    The essential oil composition of Bothriochloa velutina has been studied. The principal compounds of essential oils of three South American endemics, B. eurylemma, B. meridionalis and B. velutina were isolated. In laboratory bioassays, the principal compounds inhibited the seed germination and root and shoot growth of lettuce (Lactuca sativa L.), maize (Zea mays L.), wintergreen paspalum (Paspalum guenoarum Arechav.) and lovegrass [Eragrostis curvula (Schard.) Nees] test species. The aqueous extracts from different plant parts of three species of Bothriochloa inhibited the seed germination and root and shoot growth of test species. Aqueous extracts were more inhibitory to shoot and root elongation than to seed germination. Significant inhibition in shoot length at all concentrations indicated the phytotoxic activity of extracts. The toxicity enhanced with increasing aqueous extract concentrations. The compounds isolated can interfere with seed germination and seedling growth of plants. Consequently, the study of these chemical interactions might be useful to develop new classes of environmentally safe herbicides.Fil: Scrivanti, Lidia Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Anton, Ana Maria Ramona. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

    O pH da calda de aplicação e a absorção de ácido giberélico por frutas de laranja cv. ‘Valência’ The solution pH on gibberellic acid uptake by cv. ‘Valência’ orange fruits

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    Com o objetivo de estudar os efeitos que o ácido giberélico causa em frutas de laranja ‘Valência’, quando aplicado em diferentes concentrações, e também sob diferentes pH na calda de aplicação, foi realizado experimento onde os tratamentos consistiram de 5 concentrações (0, 5, 10, 15 e 20 ppm) e 3 pHs (3, 4,5 e 6). A aplicação foi feita em maio, quando as frutas estavam com coloração verde-amarelada, e as coletas para avaliação feitas a cada 30 dias, até o mês de novembro. Foram feitas 7 coletas no total. As variáveis estudadas foram coloração da epiderme, espessura da casca, pH do suco, acidez total titulável (ATT), teor de sólidos solúveis totais (SST), relação SST/ATT, índice tecnológico e rendimento de suco. Os resultados obtidos não permitiram concluir que o ácido giberélico tenha influência sobre as características fisico-químicas do suco, tais como pH, rendimento, SST, AT, Ratio e índice tecnológico. A espessura da casca também não foi influenciada pelo AG3. No entanto, o ácido giberélico reteve a coloração verde da casca, segundo um gradiente no que diz respeito à concentração, no sentido de que ao aumentá-la, manteve por mais tempo a coloração verde das frutas. Este comportamento foi observado em maior ou menor escala, em todos os pHs da solução. O pH=3 da calda de aplicação foi o que reteve por mais tempo a coloração verde nas frutas, indicando assim que o ácido giberélico foi mais absorvido neste pH, do que nos demais. O pH normal (4,5) reteve a coloração verde das frutas por mais tempo que o pH=6, indicando assim que pHs mais ácidos favorecem a absorção do ácido giberélico pelas plantas. Foi observado também que o ácido giberélico atrasou o fenômeno do reverdecimento, o qual ocorre quando as temperaturas se tornam mais altas.<br>The objective of this work was to study the effect of gibberellic acid on "Valência" orange fruits, when applied at various concentrations, under different solution pH. The treatments consisted of 5 concentrations of gibberellic acid (0; 5; 10; 15; and 20 ppm) and 3 pHs (3; 4.5; and 6). The aplication was made in May, when fruits were at green-yellow stage, and samples were collected every 30 days until November. The variables studied were coloration and thickness of the peel, total soluble solids (TSS), pH of juice, percent of juice, total acid (TA), ratio TSS/TA and technological index. The results obtained did not allow to conclude that gibberellic acid had any influence on the characteristics of the juice. The thickness of the peel was not affected by gibberellic acid. However, gibberellic acid caused a retaintion of the green color of the peel with increasing concentration, causing the fruits to remain greener. This was observed for all solution pHs. At pH 3, the fruits were greener than under the other pHs, and at the normal pH (4.5) The green coloration in the fruits persisted for a louger time than at pH=6, suggesting that acid pHs increase the uptake of gibberelic acid by the plants. It was also observed that gibberellic acid delayed the regreening of the fruits, what happens when the temperature becomes higher
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