3,654 research outputs found

    Oregon Wine History Projectâ„¢ Interview Transcript: Diana Lett

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    This document is a transcription of the interview with winemaker Diana Lett conducted by Jeff D. Peterson on July 9, 2010 as part of the Oregon Wine History Projectâ„¢. Diana Lett discusses the early days of the Oregon wine industry and gives her personal account of how she came to grow grapes and produce wines in the Willamette Valley. Assisting in the production of this interview were videographers Barrett Dahl and Mark Pederson; exhibit and collections coordinators Barrett Dahl, Sara Juergensen, and Keni Sturgeon (faculty advisor); project historical researchers Dulce Kersting and Lissa Wadewitz (faculty advisor). The duration of the interview is 49 minutes and 18 seconds

    Stomatal control of leaf fluxes of carbonyl sulfide and CO<sub>2</sub> in a <i>Typha</i> freshwater marsh

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    Carbonyl sulfide (COS) is an emerging tracer to constrain land photosynthesis at canopy to global scales, because leaf COS and CO2 uptake processes are linked through stomatal diffusion. The COS tracer approach requires knowledge of the concentration normalized ratio of COS uptake to photosynthesis, commonly known as the leaf relative uptake (LRU). LRU is known to increase under low light, but the environmental controls over LRU variability in the field are poorly understood due to scant leaf scale observations.Here we present the first direct observations of LRU responses to environmental variables in the field. We measured leaf COS and CO2 fluxes at a freshwater marsh in summer 2013. Daytime leaf COS and CO2 uptake showed similar peaks in the mid-morning and late afternoon separated by a prolonged midday depression, highlighting the common stomatal control on diffusion. At night, in contrast to CO2, COS uptake continued, indicating partially open stomata. LRU ratios showed a clear relationship with photosynthetically active radiation (PAR), converging to 1.0 at high PAR, while increasing sharply at low PAR. Daytime integrated LRU (calculated from daytime mean COS and CO2 uptake) ranged from 1 to 1.5, with a mean of 1.2 across the campaign, significantly lower than the previously reported laboratory mean value (∼ 1.6). Our results indicate two major determinants of LRU – light and vapor deficit. Light is the primary driver of LRU because CO2 assimilation capacity increases with light, while COS consumption capacity does not. Superimposed upon the light response is a secondary effect that high vapor deficit further reduces LRU, causing LRU minima to occur in the afternoon, not at noon. The partial stomatal closure induced by high vapor deficit suppresses COS uptake more strongly than CO2 uptake because stomatal resistance is a more dominant component in the total resistance of COS. Using stomatal conductance estimates, we show that LRU variability can be explained in terms of different patterns of stomatal vs. internal limitations on COS and CO2 uptake. Our findings illustrate the stomata-driven coupling of COS and CO2 uptake during the most photosynthetically active period in the field and provide an in situ characterization of LRU – a key parameter required for the use of COS as a photosynthetic tracer

    Strong low-frequency quantum correlations from a four-wave mixing amplifier

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    We show that a simple scheme based on nondegenerate four-wave mixing in a hot atomic vapor behaves like a near-perfect phase-insensitive optical amplifier, which can generate bright twin beams with a measured quantum noise reduction in the intensity difference of more than 8 dB, close to the best optical parametric amplifiers and oscillators. The absence of a cavity makes the system immune to external perturbations, and the strong quantum noise reduction is observed over a large frequency range.Comment: 4 pages, 4 figures. Major rewrite of the previous version. New experimental results and further analysi

    A Compact Source for Quantum Image Processing with Four-wave Mixing in Rubidium-85

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    We have built a compact light source for bright squeezed twin-beams at 795\,nm based on four-wave-mixing in atomic 85^{85}Rb vapor. With a total optical power of 400\,mW derived from a free running diode laser and a tapered amplifier to pump the four-wave-mixing process, we achieve 2.1\,dB intensity difference squeezing of the twin beams below the standard quantum limit, without accounting for losses. Squeezed twin beams generated by the type of source presented here could be used as reference for the precise calibration of photodetectors. Transferring the quantum correlations from the light to atoms in order to generate correlated atom beams is another interesting prospect. In this work we investigate the dispersion that is generated by the employed four-wave-mixing process with respect to bandwidth and dependence on probe detuning. We are currently using this squeezed light source to test the transfer of spatial information and quantum correlations through media of anomalous dispersion.Comment: 6 pages, 4 figure

    No hay diferencias en la diversidad genética entre arbustos de Cotoneaster franchetii (Rosaceae) de rangos nativos y no nativos

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    La diversidad genética de los arbustos de Cotoneaster franchetii es similar entre los rangos de distribución nativo y no nativo. Debido al efecto fundador comúnmente se asume que las plantas tienen mayor diversidad genética en su rango nativo que en las áreas donde fueron introducidos. Sin embargo, pocos estudios han probado este supuesto incluyendo la comparación entre los rangos nativos y no nativos. Nosotros analizamos marcadores de AFLP en 149 individuos de Cotoneaster franchetii pertenecientes a cinco poblaciones nativas (China) y cinco no nativas (Argentina) donde este arbusto invade exitosamente diferentes ambientes, y forma rodales extensos y monoespecíficos. Además comparamos los estimadores de diversidad genética y evaluamos la diferenciación genética entre las poblaciones examinando los valores de Fst y realizando un ACoP, un AMOVA y una prueba de Mantel. No se encontró evidencia de diversidad genética reducida en las poblaciones no nativas, mientras que el ACoP reveló dos grupos distintos, reflejando sus orígenes argentinos y chinos. Diez individuos de dos de las poblaciones chinas fueron la excepción, debido a que se agruparon dentro de las poblaciones argentinas, apoyando la idea de introducciones múltiples desde China hacia Argentina.It is commonly assumed that plants have more genetic diversity in their native range than in areas where they have been introduced due to founder effects. However, few studies have proven this assumption and included the comparison between non-native and native ranges. We analyzed AFLP fingerprint patterns of 149 individuals from five native (China) and five non-native (Argentina) populations of Cotoneaster franchetii, a shrub which successfully invades different habitats and forms extensive monospecific stands. We compared genetic diversity estimates and assessed genetic differentiation among populations by inspecting FST values and conducting a PCoA, an AMOVA and a Mantel test. No evidence was found for reduced genetic diversity in non-native populations while the PCoA revealed two distinct groups, reflecting their Chinese and Argentine origin. The exceptions were ten individuals from two Chinese populations that clustered within the Argentine populations, supporting the idea of multiple introductions from China to Argentina.Fil: Lett, Irene. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Ecología y Recursos Naturales Renovables; ArgentinaFil: Hensen, Isabell. Martin Luther University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden; Alemania. German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig; AlemaniaFil: Hirsh, Heidi. Martin Luther University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden; Alemania. Stellenbosch University, Centre for Invasion Biology, Department of Botany and Zoology; SudáfricaFil: Renison, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentin

    Anaesthesia in Hong Kong: evolution and present position

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