230 research outputs found

    Parametric amplification of vacuum fluctuations in a spinor condensate

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    Parametric amplification of vacuum fluctuations is crucial in modern quantum optics, enabling the creation of squeezing and entanglement. We demonstrate the parametric amplification of vacuum fluctuations for matter waves using a spinor F=2 Rb-87 condensate. Interatomic interactions lead to correlated pair creation in the m_F= +/- 1 states from an initial unstable m_F=0 condensate, which acts as a vacuum for m_F unequal 0. Although this pair creation from a pure m_F=0 condensate is ideally triggered by vacuum fluctuations, unavoidable spurious initial m_F= +/- 1 atoms induce a classical seed which may become the dominant triggering mechanism. We show that pair creation is insensitive to a classical seed for sufficiently large magnetic fields, demonstrating the dominant role of vacuum fluctuations. The presented system thus provides a direct path towards the generation of non-classical states of matter on the basis of spinor condensates.Comment: 5 pages, 4 figure

    Multi-resonant spinor dynamics in a Bose-Einstein condensate

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    We analyze the spinor dynamics of a Rb-87 F=2 condensate initially prepared in the m_F=0 Zeeman sublevel. We show that this dynamics, characterized by the creation of correlated atomic pairs in m_F=+/-1, presents an intriguing multi-resonant magnetic field dependence induced by the trap inhomogeneity. This dependence is directly linked to the most unstable Bogoliubov spin excitations of the initial m_F = 0 condensate, showing that, in general, even a qualitative understanding of the pair creation efficiency in a spinor condensate requires a careful consideration of the confinement.Comment: 5 pages, 4 figure

    Designing for a Moving Target

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    B814: Performance Evaluations of Potato Clones and Varieties in the Northeastern States - 1985

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    New potato clones and varieties must be tested against commercially accepted cultivars to determine If they possess advantages over existing varieties. Possible Improvements over the existing varieties could Include greater disease resistance or tolerance, higher yield, more uniform tuber size distribution, Improved storagability, good processing characteristics, etc. Often new cultivars are sought to fill local special-purpose needs. The cooperative potato variety trials reported In this bulletin were conducted to provide Information on the performance, adaptation, and performance stability of new potato clones under a wide range of geographic, climatic, soil, and cultural conditions. These tests are contributions to Regional Project NE-107 entitled, Breeding and Evaluation of New Potato Clones for the Northeast. The objectives of this regional project are: 1). To develop high quality, widely adapted, productive, pest resistant potato varieties for use In the northeast; 2). To determine regional performance, quality, and storage characteristics for promising potato clones and new varieties; 3). To evaluate promising clones and varieties for special-purpose needs such as pest outbreaks, processing, export, specialized market opportunities and/or production situations; 4). To develop management practices such as plant population, fertilizer rate, disease, weed, and Insect control strategies that will I Improve the yield and/or quality of promising clones. Data presented In this report primarily address objectives 2 and 3.https://digitalcommons.library.umaine.edu/aes_bulletin/1118/thumbnail.jp

    B801: Performance Evaluations of Potato Clones and Varieties in the Northeastern States 1983

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    Cooperative potato clone and variety trials were conducted at 23 locations to determine field, storage, and processing behavior of selected clones and varieties grown under soil, climatic, and cultural management common to the potato growing areas of 13 cooperating states and the Province of New Brunswick, Canada. These tests are all contributions to Regional Project NE107 entitled, Breeding and Evaluation of New Potato Clones for the Northeast. The primary objective of this project is to determine clone stability over a wide range of soil, climate, and cultural conditions.https://digitalcommons.library.umaine.edu/aes_bulletin/1119/thumbnail.jp

    Cognitive function is associated with risk aversion in community-based older persons

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    <p>Abstract</p> <p>Background</p> <p>Emerging data from younger and middle-aged persons suggest that cognitive ability is negatively associated with risk aversion, but this association has not been studied among older persons who are at high risk of experiencing loss of cognitive function.</p> <p>Methods</p> <p>Using data from 369 community-dwelling older persons without dementia from the Rush Memory and Aging Project, an ongoing longitudinal epidemiologic study of aging, we examined the correlates of risk aversion and tested the hypothesis that cognition is negatively associated with risk aversion. Global cognition and five specific cognitive abilities were measured via detailed cognitive testing, and risk aversion was measured using standard behavioral economics questions in which participants were asked to choose between a certain monetary payment (15)versusagambleinwhichtheycouldgainmorethan15) versus a gamble in which they could gain more than 15 or gain nothing; potential gamble gains ranged from 21.79to21.79 to 151.19 with the gain amounts varied randomly over questions. We first examined the bivariate associations of age, education, sex, income and cognition with risk aversion. Next, we examined the associations between cognition and risk aversion via mixed models adjusted for age, sex, education, and income. Finally, we conducted sensitivity analyses to ensure that our results were not driven by persons with preclinical cognitive impairment.</p> <p>Results</p> <p>In bivariate analyses, sex, education, income and global cognition were associated with risk aversion. However, in a mixed effect model, only sex (estimate = -1.49, standard error (SE) = 0.39, p < 0.001) and global cognitive function (estimate = -1.05, standard error (SE) = 0.34, p < 0.003) were significantly inversely associated with risk aversion. Thus, a lower level of global cognitive function and female sex were associated with greater risk aversion. Moreover, performance on four out of the five cognitive domains was negatively related to risk aversion (<it>i.e</it>., semantic memory, episodic memory, working memory, and perceptual speed); performance on visuospatial abilities was not.</p> <p>Conclusion</p> <p>A lower level of cognitive ability and female sex are associated with greater risk aversion in advanced age.</p

    Response to Comment on “Estimating the reproducibility of psychological science”

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    Gilbert et al. conclude that evidence from the Open Science Collaboration's Reproducibility Project: Psychology indicates high reproducibility, given the study methodology. Their very optimistic assessment is limited by statistical misconceptions and by causal inferences from selectively interpreted, correlational data. Using the Reproducibility Project: Psychology data, both optimistic and pessimistic conclusions about reproducibility are possible, and neither are yet warranted.status: publishe

    Effective Treatment of Respiratory Alphaherpesvirus Infection Using RNA Interference

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    BACKGROUND: Equine herpesvirus type 1 (EHV-1), a member of the Alphaherpesvirinae, is spread via nasal secretions and causes respiratory disease, neurological disorders and abortions. The virus is a significant equine pathogen, but current EHV-1 vaccines are only partially protective and effective metaphylactic and therapeutic agents are not available. Small interfering RNAs (siRNA's), delivered intranasally, could prove a valuable alternative for infection control. siRNA's against two essential EHV-1 genes, encoding the viral helicase (Ori) and glycoprotein B, were evaluated for their potential to decrease EHV-1 infection in a mouse model. METHODOLOGY/PRINCIPAL FNDINGS: siRNA therapy in vitro significantly reduced virus production and plaque size. Viral titers were reduced 80-fold with 37.5 pmol of a single siRNA or with as little as 6.25 pmol of each siRNA when used in combination. siRNA therapy in vivo significantly reduced viral replication and clinical signs. Intranasal treatment did not require a transport vehicle and proved effective when given up to 12 h before or after infection. CONCLUSIONS/SIGNIFICANCE: siRNA treatment has potential for both prevention and early treatment of EHV-1 infections
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