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71.
72.
Seraj Yousef Abed Thomas A. Barta Keith L. McRoberts 《Computers & Industrial Engineering》1985,9(1):45-66
Three simulation languages are quantitatively compared in a manufacturing job shop environment. Both model size and model run length were varied to obtain data on compilation time, execution time. CPU time, memory time and the rate of change of these variables due to changes in the simulation period. 相似文献
73.
An attempt of PCS was performed for the first time in Japan. Eighteen hundred twenty-six preschool and school children were examined and the result was compared with other studies (physician's auscultation and PCG). The time requirement for a single child is approximately 1.5 min. in primary school. It took longer time in kindergarten. The heart murmur detection rate is high and the sensitivity is fairly good, although it is not so good as well-trained physician's heart murmur detection rate. PCS is not perfect, but is fairly good tool for screening. It can be used only by technician. PCS may be able to save the physician's time. 相似文献
74.
N Lang-Unnasch ME Reith J Munholland JR Barta 《Canadian Metallurgical Quarterly》1998,28(11):1743-1754
Current evidence supports the presence of a non-photosynthetic chloroplast-like organelle in several apicomplexan parasites, including Plasmodium falciparum and Toxoplasma gondii. This apicomplexan organelle, referred to here as the "plastid", may have been acquired through a primary or secondary endosymbiosis of a photosynthetic organism. Alternatively, apicomplexan plastids may have been acquired through several independent endosymbiotic events, as appears to be the case for the acquisition of chloroplasts by dinoflagellates. The likelihood of multiple origins of an apicomplexan plastid is enhanced by the close evolutionary relatedness of apicomplexan and dinoflagellate taxa. In this study, we have tested the hypothesis that apicomplexan plastids are derived from a single ancient ancestor. Two lines of evidence supporting this hypothesis are presented. First, this study supports the widespread presence of plastid DNA in apicomplexan species. Second, the topologies of the phylogenetic trees derived from plastid and nuclear-encoded rRNA gene sequences suggest the co-evolution of the DNAs localised in these two compartments. Taken together, these data support a single ancient lineage for the plastids of parasites in the phylum Apicomplexa. 相似文献
75.
M. D. Baró N. Clavaguera S. Suriñach Č. Barta N. Ryšavá A. Tříska 《Journal of Materials Science》1991,26(13):3680-3684
Differential scanning calorimetric analysis was made on three glasses of the Ge-Sb-S system in order to obtain insight into the kinetics of glass transition and of the inherent relaxation processes occurring in the glass transition region. The heat capacity of the supercooled liquid referred to as the glass was measured. The value of the heat capacity jump at the glass transition, Cp, has been obtained for each glass. These values are in good agreement with those found for similar chalcogenide glasses. The relaxation process in the glassy alloy Ge30Sb10S60 was investigated by measuring the excess heat capacity of the annealed glass in the glass transition region. A relaxation enthalpy of 2.7 meV for annealing at 595 K for 17 h was determined. A kinetic study of the glass transition in the Ge20Sb10S70 glass was done. From the change in the glass transition temperature with scanning rate, an apparent activation energy of 3.9 eV was obtained. This value agrees with those measured for the apparent activation energy of the shear viscosity in similar glasses. 相似文献
76.
Baró M. D. Suriñach S. Clavaguera-Mora M. T. Clavaguera N. Barta Č. Ryšavá N. Třiska A. 《Journal of Materials Science》1991,26(3):678-682
Differential scanning calorimetry analysis was used to gain insight on the thermal stability and calorimetric behaviour on heating of the Ge25Sb20S55 glassy alloy. The as-quenched glass shows a glass transition atT
g=570 K. From the variation ofT
g with the heating rate a value of h=240 kJ mol–1 was obtained for the activation enthalpy of the mean relaxation time. On further heating an exothermic process appears ranging from 725 to 800 K giving rise to glassy GeS2 and needle-like crystals of antimony. The microstructure of the crystallization product was obtained from X-ray diffraction and scanning electron microscopy. The resulting material shows two glass transitions. The crystallization process is explained correctly by the Johnson-Mehl-Avrami-Erofe'ev equation with a kinetic exponent ofn=1.6. The apparent activation energy of crystallization is evaluated asE=286 kJ mol–1. 相似文献
77.
L’.?Kubi?árEmail author V.?Boha? V.?Vretanár ?.?Barta G.?Neuer R.?Brandt 《International Journal of Thermophysics》2005,26(6):1949-1962
This paper discusses differences in thermophysical parameters (thermal conductivity λ, thermal diffusivity a, and specific heat c) that can be found when experimental methods with different measuring regimes are used. Two classes of methods are compared,
namely, classical methods using steady-state, equilibrium, and dynamic measuring regimes and transient methods. The data consistency
formula λ = acρ gives a picture on data reliability when single-parameter methods are used. Results of analysis are verified
on published, recommended, and measured data by transient methods considering homogenous materials (stainless steel A 310,
BK 7, Perspex) and heterogeneous materials (composite C/C–SiC, aerated autoclaved concrete). Satisfactory agreement on data
for the thermophysical parameters was found on homogenous materials only.
Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22–27, 2003, Boulder, Colorado, U.S.A. 相似文献
78.
Klinger Eric; Barta Steven G.; Maxeiner Madeline E. 《Canadian Metallurgical Quarterly》1980,39(6):1222
Following evidence that cues related to Ss' current concerns control cognitive processing, this investigation probes the concern attributes that determine concern influence on thought content. The hypothesis—based on theory implicating affect in the initiation of thought segments, in determining incentive value, and in disengagement—predicted that the frequency with which goals are thought about varies with the value and imminence of the goal and with variables related to disrupted goal striving, other affect-related variables, and intensity of commitment. Concern Dimensions Questionnaires (CDQs) were administered to 153 undergraduates to assess recent thought content and provide ratings of things thought about. Thought-sampling evidence validated the CDQ measure of thought content frequency. The CDQ data confirmed the major hypotheses for all classes of variables, indicating that commitment varies with incentive value and expectancy and that thought is more often focused on goal pursuits involving threatened personal relationships, unexpected difficulties, and high degrees of commitment. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
79.
EH Aylward AM Codori PE Barta GD Pearlson GJ Harris J Brandt 《Canadian Metallurgical Quarterly》1996,53(12):1293-1296
OBJECTIVE: To determine in presymptomatic individuals who carry the gene mutation for Huntington disease whether proximity to estimated age at onset is associated with volume of basal ganglia, as measured on magnetic resonance imaging scans. DESIGN: Survey study involving correlations between basal ganglia volume, measured blind to subject status, and estimation of subjects' age at onset. SETTING: Huntington's Disease Presymptomatic Testing Program at The Johns Hopkins University School of Medicine, Baltimore, Md. PATIENTS AND OTHER PARTICIPANTS: Subjects included 47 individuals at risk for Huntington disease (ie, off-spring of patients with Huntington disease). Twenty subjects tested positive for the gene mutation but were not symptomatic. Twenty-seven subjects tested negative. MAIN OUTCOME MEASURES: Estimated age at onset was calculated for each of 20 gene-positive individuals using an empirically derived formula based on the subject's trinucleotide repeat length and parental age at onset. Each subject's age at the time of the magnetic resonance imaging scan was subtracted from his or her estimated age at onset, yielding estimated years to onset. Volumes of caudate, putamen, and globus pallidus were measured on magnetic resonance imaging scans. RESULTS: After controlling for the subject's age at the time of the scan, significant correlations were found between volumes of all basal ganglia structures and years to onset. Gene-positive subjects who were far from onset had smaller basal ganglia volumes than gene-negative subjects for all structures except globus pallidus. Gene-positive subjects who were close to onset had smaller volumes than gene-negative subjects for all basal ganglia structures and had smaller volumes than subjects far from onset for all structures except caudate. CONCLUSIONS: The results suggest that atrophy of the basal ganglia occurs gradually, beginning years before symptom onset. 相似文献
80.
BALB/c mice were infected with the intestinal intracellular parasite Eimeria papillata to characterize lymphocyte responses and cytokine profiles throughout primary and secondary infections. Lymphocytes from the mesenteric lymph node (MLN) and the gastrointestinal tract (GIT) of infected mice were phenotypically analyzed using flow cytometry and immunofluorescence microscopy, respectively. Lymphocytes isolated from the MLN during primary infections of BALB/c mice with E. papillata do not proliferate, compared to day 0 uninfected controls, when stimulated in vitro with conconavalin A and express TH2-type cytokines (interleukin [IL]-4 and IL-10) on day 3 PI followed by the release of TH1-type cytokines (IL-2 and interferon-gamma) during patency. In the small intestine, significantly more T cells and their subsets were observed during primary infection. During secondary infections, IL-2 was the only 1 of the 4 cytokines that was expressed earlier and at higher levels in the MLN when compared to primary infections. In the small intestine, significantly more alphabeta+ and CD8+ T lymphocytes were observed in mice during secondary infection. Oocyst antigens did not induce cellular proliferation at any time point during primary or secondary infections. We conclude that primary oral infection of BALB/c mice with E. papillata is associated with localized immunosuppression that may be mediated, in part, by early TH2-type cytokines. Immunity to secondary infection may be mediated by intestinal alphabeta+ CD8+ T lymphocytes through an IL-2-dependent mechanism. 相似文献