2,514 research outputs found

    The Measurement of the Energy Intensity of Manufacturing Industries: A Principal Components Analysis

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    Energy intensity is the ratio of energy use to output. Most industries deal with several energy sources and outputs. This leads to the usual difficulties of aggregating heterogeneous inputs and outputs. We apply principal components analysis to assess the information derived from six energy intensity indicators. We use two measures of total energy use (thermal and economic) and three measures of industry output (value added, value of production, and value of shipments). The data comes from manufacturing industries in Québec, Ontario, Alberta, and British Columbia from 1976 to 1996. We find that the variation of the six energy intensity indicators that is accounted for by the first principal component is quite large. However, depending on how variables are measured, there may be significant differences in the assessment of the evolution of energy intensity for some industries. There are no particular patterns in this respect. This makes identifying benchmarks that could be used to assess future performance difficult.Energy intensity; aggregation; principal components analysis

    The Effect of Self-Concept on Math Achievement in Fourth Grade Students

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    The purpose of this study was to determine if there is a correlation between self-concept and math achievement on a standardized test for a heterogeneous group of forty-eight fourth grade students. Also studied were the relationships of self-concept and math achievement on students from single parent homes and students from two-parent households and the differences between male and female students in the areas of self-concept and math achievement. Forty-eight fourth grade students from a suburban school district in Rochester, New York were the subjects of this study. Twelve of the forty-eight were from broken homes. The math section of the Stanford Achievement Test was taken by each student. The raw score of overall math ability was used to determine math achievement. The day before the test the students completed the Coopersmith Self-Esteem Inventory. The Pearson Product Moment Method was used to determine if there was statistically significant correlation between self-concept and math achievement. A t-test was used to determine if there was a significant difference between the math scores of males and females and the math scores of students from one-parent homes and students from two-parent homes. The results of this study indicated there was no significant relationship between math achievement and self-concept. There was also no significant difference found between self-concept for females and self-concept for males and math achievement for males versus females. The data also showed no significant difference between the self-concept of students from one-parent households and students from two-parent homes and no significant difference in math achievement for students from one-parent homes and students from two-parent homes

    Searching for Dust around Hyper Metal-Poor Stars

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    We examine the mid-infrared fluxes and spectral energy distributions for metal-poor stars with iron abundances [Fe/H] 5\lesssim-5, as well as two CEMP-no stars, to eliminate the possibility that their low metallicities are related to the depletion of elements onto dust grains in the formation of a debris disk. Six out of seven stars examined here show no mid-IR excess. These non-detections rule out many types of circumstellar disks, e.g. a warm debris disk (T ⁣ ⁣290T\!\le\!290 K), or debris disks with inner radii 1\le1 AU, such as those associated with the chemically peculiar post-AGB spectroscopic binaries and RV Tau variables. However, we cannot rule out cooler debris disks, nor those with lower flux ratios to their host stars due to, e.g. a smaller disk mass, a larger inner disk radius, an absence of small grains, or even a multicomponent structure, as often found with the chemically peculiar Lambda Bootis stars. The only exception is HE0107-5240, for which a small mid-IR excess near 10 microns is detected at the 2-σ\sigma level; if the excess is real and associated with this star, it may indicate the presence of (recent) dust-gas winnowing or a binary system.Comment: Accepted for publication in Ap

    Associations of region-specific foot pain and foot biomechanics: the framingham foot study

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    BACKGROUND. Specific regions of the foot are responsible for the gait tasks of weight acceptance, single-limb support, and forward propulsion. With region foot pain, gait abnormalities may arise and affect the plantar pressure and force pattern utilized. Therefore, this study’s purpose was to evaluate plantar pressure and force pattern differences between adults with and without region-specific foot pain. METHODS. Plantar pressure and force data were collected on Framingham Foot Study members while walking barefoot at a self-selected pace. Foot pain was evaluated by self-report and grouped by foot region (toe, forefoot, midfoot, or rearfoot) or regions (two or three or more regions) of pain. Unadjusted and adjusted linear regression with generalized estimating equations was used to determine associations between feet with and without foot pain. RESULTS. Individuals with distal foot (forefoot or toes) pain had similar maximum vertical forces under the pain region, while those with proximal foot (rearfoot or midfoot) pain had different maximum vertical forces compared to those without regional foot pain (referent). During walking, there were significant differences in plantar loading and propulsion ranging from 2% to 4% between those with and without regional foot pain. Significant differences in normalized maximum vertical force and plantar pressure ranged from 5.3% to 12.4% and 3.4% to 24.1%, respectively, between those with and without regional foot pain. CONCLUSIONS. Associations of regional foot pain with plantar pressure and force were different by regions of pain. Region-specific foot pain was not uniformly associated with an increase or decrease in loading and pressure patterns regions of pain

    CONDOR: Long endurance high altitude vehicle, volume 5

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    The results of a design study resulting in the proposed CONDOR aircraft are presented. The basic requirements are for the aircraft to maintain continuous altitude at or above 45,000 feet for at least a 3-day mission, be able to comfortably support a two-man crew during this period with their field of vision not obstructed to a significant degree, carry a payload of 200 pounds, and provide a power supply to the payload of 2000 watts. The take-off and landing distances must be below 5000. feet, and time to reach cruise altitude must not exceed 3 hours. The subjects discussed are configuration selection, structural analysis, stability and control, crew and payload accomodations, and economic estimates

    Pseudoseptic Arthritis: A Case Series and Review of the Literature

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    Purpose. Pseudoseptic arthritis is an acute inflammatory monoarthritis with a sterile synovial gram stain and culture. Pseudoseptic arthritis has been previously described in the literature in a variety of settings including rheumatoid arthritis and microcrystalline disease. Despite pseudoseptic arthritis being a described entity, there is little published data on this topic with no published reports since 1992. Methods. This paper was a retrospective chart review over a 20-year period that identified all rheumatology inpatient consultations at our tertiary rural hospital for pseudoseptic arthritis. Results. We identified 10 patients with pseudoseptic arthritis and presented 5 of those cases in this paper. Majority of these patients had known autoimmune inflammatory arthritis or microcrystalline inflammatory arthritis. Conclusion. Pseudoseptic arthritis is a syndrome that should be in the differential diagnosis with patients with long standing inflammatory condition who present with an acute monoarthritis with no known bacterial source for septic arthritis

    The Chandra ACIS Survey of M33 (ChASeM33): Transient X-ray Sources Discovered in M33

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    The Chandra ACIS Survey of M33 (ChASeM33) has acquired 7 fields of ACIS data covering M33 with 200 ks of exposure in each field. A catalog from the first 10 months of data, along with archival Chandra observations dating back to the year 2000, is currently available. We have searched these data for transient sources that are measured to have a 0.35-8.0 keV unabsorbed luminosity of at least 4×1035\times10^{35} erg s1^{-1} in one epoch and are not detected in another epoch. This set of the survey data has yielded seven such sources, including one previously-known supersoft source. We analyzed XMM-Newton data from the archive distributed over the years 2000 to 2003 to search for recurrent outbursts and to get a spectrum for the supersoft transient. We find only one recurrent transient in our sample. The X-ray spectra, light curves, and optical counterpart candidates of two of the other sources suggest that they are high-mass X-ray binaries. Archival Spitzer photometry and high X-ray absorption suggest that one of the sources is a highly variable background active galactic nucleus. The other three sources are more difficult to classify. The bright transient population of M33 appears to contain a large fraction of high-mass X-ray binaries compared with the transient populations of M31 and the Galaxy, reflecting the later morphology of M33.Comment: 33 pages, 2 tables, 10 figures, accepted for publication in Ap

    The Next Generation Virgo cluster Survey. V. modelling the dynamics of M87 with the Made-to-Measure method

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    We study the dynamics of the giant elliptical galaxy M87 from the central to the outermost regions with the made-to-measure (M2M) method. We use a new catalogue of 922 globular cluster line-of- sight velocities extending to a projected radius of 180 kpc (equivalent to 25 M87 effective radii), and SAURON integral field unit data within the central 2.4 kpc. 263 globular clusters, mainly located beyond 40 kpc, are newly observed by the Next Generation Virgo Survey (NGVS). For the M2M modelling, the gravitational potential is taken as a combination of a luminous matter potential with a constant stellar mass-to-light ratio and a dark matter potential modelled as a logarithmic potential. Our best dynamical model returns a stellar mass-to-light ratio in the I band of M/LI = 6.0(+ -0.3) M_sun/L_sun with a dark matter potential scale velocity of 591(+ -50) km/s and scale radius of 42(+ -10) kpc. We determine the total mass of M87 within 180 kpc to be (1.5 + - 0.2) 10^13 M_sun. The mass within 40 kpc is smaller than previous estimates determined using globular cluster kinematics that did not extend beyond 45 kpc. With our new globular cluster velocities at much larger radii, we see that globular clusters around 40 kpc show an anomalously large velocity dispersion which affected previous results. The mass we derived is in good agreement with that inferred from ROSAT X-ray observation out to 180 kpc. Within 30 kpc our mass is also consistent with that inferred from Chandra and XMM-Newton X-ray observations, while within 120 kpc it is about 20% smaller. The model velocity dispersion anisotropy beta parameter for the globular clusters in M87 is small, varying from -0.2 at the centre to 0.2 at 40 kpc, and gradually decreasing to zero at 120 kpc.Comment: 20 pages, 16 figures, Accepted by Ap
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