3,741 research outputs found

    Financial highlights : 1974

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    An abstract for this article is not available.Financial markets

    Financial forecasts : 1975

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    An abstract for this article is not available.Financial markets

    The district economy in perspective : 1974

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    An abstract for this article is not available.Federal Reserve District, 5th

    Testing Foundations of Biological Scaling Theory Using Automated Measurements of Vascular Networks

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    Scientists have long sought to understand how vascular networks supply blood and oxygen to cells throughout the body. Recent work focuses on principles that constrain how vessel size changes through branching generations from the aorta to capillaries and uses scaling exponents to quantify these changes. Prominent scaling theories predict that combinations of these exponents explain how metabolic, growth, and other biological rates vary with body size. Nevertheless, direct measurements of individual vessel segments have been limited because existing techniques for measuring vasculature are invasive, time consuming, and technically difficult. We developed software that extracts the length, radius, and connectivity of in vivo vessels from contrast-enhanced 3D Magnetic Resonance Angiography. Using data from 20 human subjects, we calculated scaling exponents by four methods--two derived from local properties of branching junctions and two from whole-network properties. Although these methods are often used interchangeably in the literature, we do not find general agreement between these methods, particularly for vessel lengths. Measurements for length of vessels also diverge from theoretical values, but those for radius show stronger agreement. Our results demonstrate that vascular network models cannot ignore certain complexities of real vascular systems and indicate the need to discover new principles regarding vessel lengths

    Analytical method to measure three-dimensional strain patterns in the left ventricle from single slice displacement data

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    Background: Displacement encoded Cardiovascular MR (CMR) can provide high spatial resolution measurements of three-dimensional (3D) Lagrangian displacement. Spatial gradients of the Lagrangian displacement field are used to measure regional myocardial strain. In general, adjacent parallel slices are needed in order to calculate the spatial gradient in the through-slice direction. This necessitates the acquisition of additional data and prolongs the scan time. The goal of this study is to define an analytic solution that supports the reconstruction of the out-of-plane components of the Lagrangian strain tensor in addition to the in-plane components from a single-slice displacement CMR dataset with high spatio-temporal resolution. The technique assumes incompressibility of the myocardium as a physical constraint. Results: The feasibility of the method is demonstrated in a healthy human subject and the results are compared to those of other studies. The proposed method was validated with simulated data and strain estimates from experimentally measured DENSE data, which were compared to the strain calculation from a conventional two-slice acquisition. Conclusion: This analytical method reduces the need to acquire data from adjacent slices when calculating regional Lagrangian strains and can effectively reduce the long scan time by a factor of two

    Dataset concerning the analytical approximation of the Ae3 temperature.

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    In this paper we present a new polynomial function for calculating the local phase transformation temperature (Ae3 ) between the austenite+ferrite and the fully austenitic phase fields during heating and cooling of steel:[Formula: see text] The dataset includes the terms of the function and the values for the polynomial coefficients for major alloying elements in steel. A short description of the approximation method used to derive and validate the coefficients has also been included. For discussion and application of this model, please refer to the full length article entitled "The role of aluminium in chemical and phase segregation in a TRIP-assisted dual phase steel" 10.1016/j.actamat.2016.05.046 (Ennis et al., 2016) [1]

    Probing dynamic myocardial microstructure with cardiac magnetic resonance diffusion tensor imaging

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    This article is an invited editorial comment on the paper entitled “In vivo cardiovascular magnetic resonance diffusion tensor imaging shows evidence of abnormal myocardial laminar orientations and mobility in hypertrophic cardiomyopathy” by Ferreira et al., and published as Journal of Cardiovascular Magnetic Resonance 2014; 16:87

    One Millimeter Continuum Observations of High Redshift Quasars

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    Upper limits to the one-millimeter continuum flux densities of the high redshift quasars 82 1225 + 31, Ton 490, and PHL 957 are presented. The upper limit to the power observed from these quasars at I mm is, on average, ½ the observed power in the continuum at Lɑ. These observations are used to constrain the temperature of a hypothètical dust shell which reddens the quasar line and continuum emission by an extinction optical depth sufficient to account for the anomalously low Lɑ/Hɑ emission line ratio observed in each of these quasars. For the quasars studied, dust shell temperatures between 25 K and 50 to 95 K are prohibited by the present data. A dust shell at a temperature within this span reradiating all the power absorbed from the quasar ultraviolet continuum would produce a one-millimeter flux density greater than the measured upper limit. The average radius of the model dust shell cannot be between 70 kpc and 1 Mpc

    Nuclear Shell Model by the Quantum Monte Carlo Diagonalization Method

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    The feasibility of shell-model calculations is radically extended by the Quantum Monte Carlo Diagonalization method with various essential improvements. The major improvements are made in the sampling for the generation of shell-model basis vectors, and in the restoration of symmetries such as angular momentum and isospin. Consequently the level structure of low-lying states can be studied with realistic interactions. After testing this method on 24^{24}Mg, we present first results for energy levels and E2E2 properties of 64^{64}Ge, indicating its large and γ\gamma-soft deformation.Comment: 12 pages, RevTex, 2 figures, to be published in Physical Review Letter

    Weight Management Program for Fire Fighters: Feasibility Pilot

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    Please view abstract in the attached PDF fil
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