251 research outputs found

    Analysis Of The Influence Of Agricultural And Non-Agricultural Sectors Performance On The Nigerian Economy (1986-2004)

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    This paper examines the influence of agricultural and non-agricultural economies on Nigeria\'s total economy. Time series data such as Nigeria\'s total GDP, Agricultural GDP and non-agricultural GDP were obtained. A double logarithm and exponential functions were used to estimate the elasticity and growth rate of each sector and the economy as a whole. The results revealed that a % change in Agricultural and Non-agricultural sectors caused the Nigerian economy to change by 0.24% and 0.746% respectively. The agricultural, non-agricultural sector and the entire economy grew at the rate of 0.04%, 0.124% and 0.102% respectively during the study period. Keywords: Agricultural sector, Non-agricultural sector, Nigerian economy. Global Journal of Agricultural Sciences Vol. 7 (1) 2008: pp. 7-

    High-precision CTE measurement of hybrid C/SiC composite for cryogenic space telescopes

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    This paper presents highly precise measurements of thermal expansion of a "hybrid" carbon-fiber reinforced silicon carbide composite, HB-Cesic\textregistered - a trademark of ECM, in the temperature region of \sim310-10K. Whilst C/SiC composites have been considered to be promising for the mirrors and other structures of space-borne cryogenic telescopes, the anisotropic thermal expansion has been a potential disadvantage of this material. HB-Cesic\textregistered is a newly developed composite using a mixture of different types of chopped, short carbon-fiber, in which one of the important aims of the development was to reduce the anisotropy. The measurements indicate that the anisotropy was much reduced down to 4% as a result of hybridization. The thermal expansion data obtained are presented as functions of temperature using eighth-order polynomials separately for the horizontal (XY-) and vertical (Z-) directions of the fabrication process. The average CTEs and their dispersion (1{\sigma}) in the range 293-10K derived from the data for the XY- and Z-directions were 0.805±\pm0.003\times10−6^{-6} K−1^{-1} and 0.837\pm0.001\times10−6^{-6} K−1^{-1}, respectively. The absolute accuracy and the reproducibility of the present measurements are suggested to be better than 0.01\times10−6^{-6} K−1^{-1} and 0.001\times(10)^{-6} K^{-1}, respectively. The residual anisotropy of the thermal expansion was consistent with our previous speculation regarding carbon-fiber, in which the residual anisotropy tended to lie mainly in the horizontal plane.Comment: Accepted by Cryogeincs. 12 pages, 3 figures, 1 tabll

    The International Grief Questionnaire (IGQ): A new measure of ICD-11 Prolonged Grief Disorder.

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    Prolonged grief disorder (PGD) is included in the 11th version of the International Statistical Classification of Diseases and Related Health Problems (ICD‐11). This study sought to test the validity and reliability of a new brief measure to screen for ICD‐11 PGD—the International Grief Questionnaire (IGQ). The psychometric properties of the IGQ were tested using data collected from two bereaved samples of adults from the United Kingdom (n = 1,012) and Ireland (n = 1,011). Confirmatory factor analysis demonstrated that a correlated two‐factor model best captured the latent dimensionality of the IGQ in both samples. Estimates of internal reliability were high, whereas the convergent and concurrent validity of the scale were supported through strong associations with external measures. Measurement invariance and differential item functioning testing showed no statistically significant difference in the latent structure of the IGQ nor the functioning of the IGQ items by age, sex, and nationality. For participants who were bereaved for more than 6 months, the rates of probable PGD derived from the IGQ were 10.9% and 15.3% for the Irish and U.K. samples, respectively. The IGQ is a brief, easy‐to‐use, self‐report screening measure that captures all diagnostic criteria of PGD set forth in the ICD‐11. Findings from this study provide initial support for the validity, measurement invariance, and reliability of the IGQ among two national samples

    High Precision CTE-Measurement of SiC-100 for Cryogenic Space-Telescopes

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    We present the results of high precision measurements of the thermal expansion of the sintered SiC, SiC-100, intended for use in cryogenic space-telescopes, in which minimization of thermal deformation of the mirror is critical and precise information of the thermal expansion is needed for the telescope design. The temperature range of the measurements extends from room temperature down to ∌\sim 10 K. Three samples, #1, #2, and #3 were manufactured from blocks of SiC produced in different lots. The thermal expansion of the samples was measured with a cryogenic dilatometer, consisting of a laser interferometer, a cryostat, and a mechanical cooler. The typical thermal expansion curve is presented using the 8th order polynomial of the temperature. For the three samples, the coefficients of thermal expansion (CTE), \bar{\alpha}_{#1}, \bar{\alpha}_{#2}, and \bar{\alpha}_{#3} were derived for temperatures between 293 K and 10 K. The average and the dispersion (1 σ\sigma rms) of these three CTEs are 0.816 and 0.002 (×10−6\times 10^{-6}/K), respectively. No significant difference was detected in the CTE of the three samples from the different lots. Neither inhomogeneity nor anisotropy of the CTE was observed. Based on the obtained CTE dispersion, we performed an finite-element-method (FEM) analysis of the thermal deformation of a 3.5 m diameter cryogenic mirror made of six SiC-100 segments. It was shown that the present CTE measurement has a sufficient accuracy well enough for the design of the 3.5 m cryogenic infrared telescope mission, the Space Infrared telescope for Cosmology and Astrophysics (SPICA).Comment: in press, PASP. 21 pages, 4 figure
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