46,751 research outputs found

    Strongly Coupled Matter-Field and Non-Analytic Decay Rate of Dipole Molecules in a Waveguide

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    The decay rate \gam of an excited dipole molecule inside a waveguide is evaluated for the strongly coupled matter-field case near a cutoff frequency \ome_c without using perturbation analysis. Due to the singularity in the density of photon states at the cutoff frequency, we find that \gam depends non-analytically on the coupling constant \ggg as 4/3\ggg^{4/3}. In contrast to the ordinary evaluation of \gam which relies on the Fermi golden rule (itself based on perturbation analysis), \gam has an upper bound and does not diverge at \ome_c even if we assume perfect conductance in the waveguide walls. As a result, again in contrast to the statement found in the literature, the speed of emitted light from the molecule does not vanish at \ome_c and is proportional to c2/3c\ggg^{2/3} which is on the order of 10310410^3 \sim 10^4 m/s for typical dipole molecules.Comment: 4 pages, 2 figure

    Studies on the flight medical aspects of the German Lufthansa non-stop route from Frankfurt to Rio de Janeiro, part 1

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    The problem of crew size for regularly scheduled flights between Frankfurt and Rio de Janeiro is discussed. Factors affecting crew performance are examined, comparisons are drawn to regulations of other countries and crew questionnaires and tests are presented

    Water vapor diffusion membranes, 2

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    Transport mechanisms were investigated for the three different types of water vapor diffusion membranes. Membranes representing porous wetting and porous nonwetting structures as well as dense diffusive membrane structures were investigated for water permeation rate as a function of: (1) temperature, (2) solids composition in solution, and (3) such hydrodynamic parameters as sweep gas flow rate, solution flow rate and cell geometry. These properties were measured using nitrogen sweep gas to collect the effluent. In addition, the chemical stability to chromic acid-stabilized urine was measured for several of each type of membrane. A technology based on the mechanism of vapor transport was developed, whereby the vapor diffusion rates and relative susceptibility of membranes to fouling and failure could be projected for long-term vapor recovery trials using natural chromic acid-stabilized urine

    The Impact of Trade Barriers on Mandated Biofuel Consumption in Canada

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    In 2008 the Canadian government passed amendments to the Environmental Protection Act requiring five percent ethanol in transportation fuels sold in Canada by 2010 and two percent renewable content in diesel and heating fuels by 2012. Agricultural commodity and other groups have lobbied for further marketplace intervention that would ensure the biofuel needed to meet the legislated requirement be produced from domestic sources. Indeed, many of these special interests would like the biofuels content increased from five to ten percent and for the increase to be met by domestic firms only. The objective of this study is to compare the relative economic impacts in Canada of achieving a ten percent biofuel content either through increased imports or by substituting domestic production in place of increased imports.biofuel trade policy ethanol canada, Demand and Price Analysis, International Relations/Trade,

    The Impact of Trade Barriers on Mandated Biofuel Consumption in Canada

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    biofuel ethanol trade Canada, Agricultural and Food Policy, Demand and Price Analysis, International Relations/Trade,

    A psychoanalytic concept illustrated: Will, must, may, can — revisiting the survival function of primitive omnipotence

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    The author explores the linear thread connecting the theory of Freud and Klein, in terms of the central significance of the duality of the life and death instinct and the capacity of the ego to tolerate contact with internal and external reality. Theoretical questions raised by later authors, informed by clinical work with children who have suffered deprivation and trauma in infancy, are then considered. Theoretical ideas are illustrated with reference to observational material of a little boy who suffered deprivation and trauma in infancy. He was first observed in the middle of his first year of life while he was living in foster care, and then later at the age of two years and three months, when he had been living with his adoptive parents for more than a year

    Relationship of glycemic control, exogenous insulin, and C-peptide levels to ischemic heart disease mortality over a 16-year period in people with older-onset diabetes: the Wisconsin Epidermologic Study of Diabetic Retinopathy (WESDR)

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    OBJECTIVE - the purpose of this study was to examine the relationship of glycemic control and exogenous and endogenous insulin levels with all-cause and cause-specific mortality (ischemic heart disease and stroke) in an older-onset diabetic population.RESEARCH DESIGN and METHODS - the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) is an ongoing, prospective, population-based cohort study of individuals with diabetes first examined in 1980-1982. A stratified sample of all individuals with diabetes diagnosed at 30 years of age or older was labeled older-onset (n = 1,370). Those participating in the 1984-1986 examination phase (n = 1,007) were included in the analysis. Endogenous insulin was determined by measurements of plasma C-peptide (in nanomoles per liter), and exogenous insulin was calculated in units per kilogram per day. Glycemic control was determined by levels of glycosylated hemoglobin (HbA(1)).RESULTS - After 16 years of follow-up, 824 individuals died (all-cause mortality); 358 deaths involved ischemic heart disease and 137 involved stroke. C-peptide and HbA(1) were significantly associated with all-cause and ischemic heart disease mortality in our study. the hazard ratio (95% CI) values for all-cause mortality were 1.12 (1.07-1.17) per 1% increase in HbA, 1.20 (0.85-1.69) per 1 unit . kg(-1) - day(-1) increase in exogenous insulin, and 1.15 (1.04-1.29) per 1 nmol/l increase in C-peptide and for ischemic heart disease mortality were 1.14 (1.06-1.22), 1.50 (0.92-2.46), and 1.19 (1.02-1.39) for HbA(1), exogenous insulin, and C-peptide, respectively, after adjusting for relevant confounders. C-peptide was associated with stroke mortality only among men (1.65 [1.07-2.53]).CONCLUSIONS - Our results show that individuals with higher endogenous insulin levels are at higher risk of all-cause, ischemic heart disease, and stroke mortality.Univ Wisconsin, Sch Med & Publ Hlth, Dept Ophthalmol & Visual Sci, Madison, WI 53726 USAUniversidade Federal de São Paulo, São Paulo, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilWeb of Scienc

    25 kHz narrow spectral bandwidth of a wavelength tunable diode laser with a short waveguide-based external cavity

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    We report on the spectral properties of a diode laser with a tunable external cavity in integrated optics. Even though the external cavity is short compared to other small-bandwidth external cavity lasers, the spectral bandwidth of this tunable laser is as small as 25 kHz (FWHM), at a side-mode suppression ratio (SMSR) of 50 dB. Our laser is also able to access preset wavelengths in as little as 200 us and able to tune over the full telecom C-band (1530 nm - 1565 nm).Comment: 8 pages, 7 figure
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