9,312 research outputs found

    An archival case study : revisiting the life and political economy of Lauchlin Currie

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    This paper forms part of a wider project to show the significance of archival material on distinguished economists, in this case Lauchlin Currie (1902-93), who studied and taught at Harvard before entering government service at the US Treasury and Federal Reserve Board as the intellectual leader of Roosevelt's New Deal, 1934-39, as FDR's White House economic adviser in peace and war, 1939-45, and as a post-war development economist. It discusses the uses made of the written and oral material available when the author was writing his intellectual biography of Currie (Duke University Press 1990) while Currie was still alive, and the significance of the material that has come to light after Currie's death

    Socioeconomic inequalities in childhood exposure to secondhand smoke before and after smoke-free legislation in three UK countries

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    Background: Secondhand smoke (SHS) exposure is higher among lower socioeconomic status (SES) children. Legislation restricting smoking in public places has been associated with reduced childhood SHS exposure and increased smoke-free homes. This paper examines socioeconomic patterning in these changes.<p></p> Methods: Repeated cross-sectional survey of 10 867 schoolchildren in 304 primary schools in Scotland, Wales and Northern Ireland. Children provided saliva for cotinine assay, completing questionnaires before and 12 months after legislation.<p></p> Results: SHS exposure was highest, and private smoking restrictions least frequently reported, among lower SES children. Proportions of saliva samples containing <0.1 ng/ml (i.e. undetectable) cotinine increased from 31.0 to 41.0%. Although across the whole SES spectrum, there was no evidence of displacement of smoking into the home or increased SHS exposure, socioeconomic inequality in the likelihood of samples containing detectable levels of cotinine increased. Among children from the poorest families, 96.9% of post-legislation samples contained detectable cotinine, compared with 38.2% among the most affluent. Socioeconomic gradients at higher exposure levels remained unchanged. Among children from the poorest families, one in three samples contained > 3 ng/ml cotinine. Smoking restrictions in homes and cars increased, although socioeconomic patterning remained.<p></p> Conclusions Urgent action is needed to reduce inequalities in SHS exposure. Such action should include emphasis on reducing smoking in cars and homes

    Hamiltonian Formulation of Two Body Problem in Wheeler-Feynman electrodynamics

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    A Hamiltonian formulation for the classical problem of electromagnetic interaction of two charged relativistic particles is found.Comment: 22 pages, 8 Uuencoded Postscript figure

    Transition Property for α\alpha-Power Free Languages with α2\alpha\geq 2 and k3k\geq 3 Letters

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    In 1985, Restivo and Salemi presented a list of five problems concerning power free languages. Problem 44 states: Given α\alpha-power-free words uu and vv, decide whether there is a transition from uu to vv. Problem 55 states: Given α\alpha-power-free words uu and vv, find a transition word ww, if it exists. Let Σk\Sigma_k denote an alphabet with kk letters. Let Lk,αL_{k,\alpha} denote the α\alpha-power free language over the alphabet Σk\Sigma_k, where α\alpha is a rational number or a rational "number with ++". If α\alpha is a "number with ++" then suppose k3k\geq 3 and α2\alpha\geq 2. If α\alpha is "only" a number then suppose k=3k=3 and α>2\alpha>2 or k>3k>3 and α2\alpha\geq 2. We show that: If uLk,αu\in L_{k,\alpha} is a right extendable word in Lk,αL_{k,\alpha} and vLk,αv\in L_{k,\alpha} is a left extendable word in Lk,αL_{k,\alpha} then there is a (transition) word ww such that uwvLk,αuwv\in L_{k,\alpha}. We also show a construction of the word ww

    The Critical Exponent is Computable for Automatic Sequences

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    The critical exponent of an infinite word is defined to be the supremum of the exponent of each of its factors. For k-automatic sequences, we show that this critical exponent is always either a rational number or infinite, and its value is computable. Our results also apply to variants of the critical exponent, such as the initial critical exponent of Berthe, Holton, and Zamboni and the Diophantine exponent of Adamczewski and Bugeaud. Our work generalizes or recovers previous results of Krieger and others, and is applicable to other situations; e.g., the computation of the optimal recurrence constant for a linearly recurrent k-automatic sequence.Comment: In Proceedings WORDS 2011, arXiv:1108.341

    Managing digital coordination of design: emerging hybrid practices in an institutionalized project setting

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    What happens when digital coordination practices are introduced into the institutionalized setting of an engineering project? This question is addressed through an interpretive study that examines how a shared digital model becomes used in the late design stages of a major station refurbishment project. The paper contributes by mobilizing the idea of ‘hybrid practices’ to understand the diverse patterns of activity that emerge to manage digital coordination of design. It articulates how engineering and architecture professions develop different relationships with the shared model; the design team negotiates paper-based practices across organizational boundaries; and diverse practitioners probe the potential and limitations of the digital infrastructure. While different software packages and tools have become linked together into an integrated digital infrastructure, these emerging hybrid practices contrast with the interactions anticipated in practice and policy guidance and presenting new opportunities and challenges for managing project delivery. The study has implications for researchers working in the growing field of empirical work on engineering project organizations as it shows the importance of considering, and suggests new ways to theorise, the introduction of digital coordination practices into these institutionalized settings

    CHIMPS: the <sup>13</sup>CO/C<sup>18</sup>O (<i>J</i> = 3 → 2) Heterodyne Inner Milky Way Plane Survey

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    We present the 13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey (CHIMPS) which has been carried out using the Heterodyne Array Receiver Program on the 15 m James Clerk Maxwell Telescope (JCMT) in Hawaii. The high-resolution spectral survey currently covers |b| ≤ 0.5° and 28° ≲ l ≲ 46°, with an angular resolution of 15 arcsec in 0.5 km s-1 velocity channels. The spectra have a median rms of ˜0.6 K at this resolution, and for optically thin gas at an excitation temperature of 10 K, this sensitivity corresponds to column densities of NH2 ˜ 3 × 1020 cm-2 and NH2 ˜ 4 × 1021 cm-2 for 13CO and C18O, respectively. The molecular gas that CHIMPS traces is at higher column densities and is also more optically thin than in other publicly available CO surveys due to its rarer isotopologues, and thus more representative of the three-dimensional structure of the clouds. The critical density of the J = 3 → 2 transition of CO is ≳104 cm-3 at temperatures of ≤20 K, and so the higher density gas associated with star formation is well traced. These data complement other existing Galactic plane surveys, especially the JCMT Galactic Plane Survey which has similar spatial resolution and column density sensitivity, and the Herschel infrared Galactic Plane Survey. In this paper, we discuss the observations, data reduction and characteristics of the survey, presenting integrated-emission maps for the region covered. Position-velocity diagrams allow comparison with Galactic structure models of the Milky Way, and while we find good agreement with a particular four-arm model, there are some significant deviations

    Forage Sorghum and Corn Silage Response to Full and Deficit Irrigation

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    There is limited information on forage sorghum and corn silage yield response to full and deficit irrigation in Kansas. The objective of this study was to generate information on forage sorghum (brown mid-rib hybrids (BMR and non-BMR)) and corn silage yield response to different levels of irrigation as influenced by irrigation capacity in southwest Kansas. Preliminary results indicate the effect of irrigation capacity on forage yield was significant (P = 0.0009) in 2014 but not 2015, probably due to high growing season rainfall received in 2015. Corn silage produced significantly (p \u3c 0.05) higher biomass at all irrigation capacities compared to forage sorghum hybrids in 2015. BMR forage sorghum produced significantly lower biomass compared to non-BMR hybrid in both 2014 and 2015 (P \u3c 0.05). The highest amounts of forage produced for corn silage, BMR, and non-BMR forage sorghum were 24.6, 17.4, and 21.1 tons/a adjusted to 65%, moisture respectively. Water productivity ranged from 1.0 to 1.4 dry matter tons/a/in. More research is needed under normal and dry years to quantify forage sorghum and corn silage yield and forage quality response to full and deficit irrigation
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