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1

Digitale Medien

An investigation of acceleration waves in a perfectly conducting magnetohydrodynamic fluid (1988)

Abdullah, A. A. ; Lindsay, K. A.

Springer

Zeitschrift für angewandte Mathematik und Physik 39 (1988), S. 634-648

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ISSN: 1420-9039

Quelle: Springer Online Journal Archives 1860-2000

Thema: Mathematik , Physik

Notizen: Abstract This paper discusses the propagation of discontinuities in a perfectly conducting magnetohydrodynamic fluid, the model having been proposed by P. H. Roberts [1] in the context of neutron stars. P. H. Roberts [1] obtained a stability criterion which was subsequently reproduced by B. Straughan [3] using a discontinuity analysis but in the process the resulting sixth order secular equation decomposed into a product of quadratic and quartic polynomial factors. The first section of this paper investigates the reason for this factorization and the latter sections examine the nature of the equations governing the behaviour of the discontinuity amplitudes. The presence of the magnetic field effectively makes the fluid non-isotropic and so the determination of amplitude equations is non standard although they finally prove to be of Bernoulli type.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00948727

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2

Digitale Medien

Analyzing spatial disparities in access to health care: A methodology with application in Bangladesh (1985)

Khan, Abdullah A.

Springer

GeoJournal 10 (1985), S. 91-107

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ISSN: 1572-9893

Quelle: Springer Online Journal Archives 1860-2000

Thema: Geographie

Notizen: Abstract This paper develops a methodology for analyzing spatial disparities in access to health care in situations where the data base is limited, and applies it in the context of Bangladesh. The proposed indirect measures of inpatient and outpatient service utilization, and of quality of available services, seem to provide reasonably accurate, consistent, and interpretable results; these indices are combined into a composite index of relative access to health care. The form of the composite index and its components permits the incorporation of Sopher's disparity index into the methodology for measuring urban-rural disparities in relative access to health care. The empirical analysis based on subdivision level data revealed that Bangladesh's health care delivery system is, in general, characterized by extremely low level of access and a high degree of disparity in favor of urban areas, especially in terms of inpatient services. Spatial patterns of relative access and urban/rural disparity were perused through cartographic and statistical analyses; although clear-cut regional patterns did not emerge, the considerable spatial variations could be explained largely with reference to urbanization and density of population. Assuming improved level of access and minimal urban/rural disparity as basic policy goals a method to prioritize spatial units for future allocation of health sector resources is recommended.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00174672

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3

Digitale Medien

Synthesis and Antimicrobial Activity of New Furan Derivatives (1985)

El-Obeid, Humeida A. ; Elnima, Elamin I. ; Al-Badr, Abdullah A.

Springer

Pharmaceutical research 2 (1985), S. 42-43

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ISSN: 1573-904X

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie

Notizen: Abstract 5-Nitrofuran derivatives were synthesized and their antibacterial activity was investigated using standard bacterial strains and clinical isolates. The compounds showed inhibitory effects on both Gram-positive and Gram-negative organisms.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1023/A:1016318106782

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4

Digitale Medien

Boundary value techniques for finite element solutions of the diffusion-convection equation (1986)

Evans, D. J. ; Abdullah, A. R.

Chichester [u.a.] : Wiley-Blackwell

International Journal for Numerical Methods in Engineering 23 (1986), S. 1145-1159

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ISSN: 0029-5981

Schlagwort(e): Engineering ; Engineering General

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Mathematik , Technik allgemein

Notizen: In this paper, the formulation of six-point and nine-point finite element equations for the solution of the diffusion-convection equation is presented. The six-point equation requires the solution of a tridiagonal system of equations and the nine-point centred equation is treated as a solution of a boundary value problem which leads to a large linear system of equations.Some numerical experiments are presented and the comparison with existing methods is included.

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/nme.1620230611

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5

Digitale Medien

Study on the Renal and Cardiovascular Activities of Aminouracil Derivatives (1989)

Mustafa, Ali A. ; Alhaider, Abdulgader A. ; Hijazi, Abdullah A.

Springer

Pharmaceutical research 6 (1989), S. 394-398

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ISSN: 1573-904X

Schlagwort(e): diuretic ; aminouracil ; cardiovascular effects

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie

Notizen: Abstract The synthesis of five 4-aminouracil derivatives has been described. These compounds, which are chemically related to xanthines, were tested for possible diuretic activity. The increase in urine output by compounds I, III, and V was comparable to that produced by caffeine in an equimolar dose (5 × 10−3 M). On the isolated rabbit's heart (Langendorff s preparation), compounds I, III, and V (5 × 10−5 M) significantly increased the amplitude of contractions without having any significant effect on heart rate. Only these three compounds (4.4 x 10−8 M) relaxed the isolated rabbit thoracic aorta and rat anococcygeus smooth muscle which were precontracted with norepinephrine (4 × 10−8 M). This action was not antagonized by atropine, propranolol, or methylene blue, ruling out the involvement of acetylcholine, beta receptors, or endothelium-derived relaxing factor (EDRF). The relaxant effect, however, was reversed by the addition of calcium chloride, suggesting that this relaxation may be due to inhibition of the entry of extracellular calcium into the cells.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1023/A:1015979314978

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6

Digitale Medien

Optimization of solid substrate fermentation of wheat straw (1985)

Abdullah, A. L. ; Tengerdy, R. P. ; Murphy, V. G.

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 27 (1985), S. 20-27

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ISSN: 0006-3592

Schlagwort(e): Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung

Notizen: Optimal conditions for solid substrate fermentation of wheat straw with Chaetomium cellulolyticum in laboratory-scale stationary layer fermenters were developed. The best pretreatment for wheat straw was ammonia freeze explosion, followed by steam treatment, alkali treatment, and simple autoclaving. The optimal fermentation conditions were 80% (w/w) moisture content; incubation temperature of 37°C; 2% (w/w) unwashed mycelial inoculum; aeration at 0.12 L/h/g; substrate thickness of 1 to 2 cm; and duration of three days. Technical parameters for this optimized fermentation were: degree of substance utilization, 27.2%; protein yield/substrate, 0.09 g; biomass yield/bioconverted substrate, 0.40 g; degree of bioconversion of total available sugars in the substrate, 60.5%; specific efficiency of bioconversion, 70.8%; and overall efficiency of biomass production from substrate, 42.7%. Mixed culturing of Candida utilis further increased biomass production by 20%. The best mode of fermentation was a semicontinuous fed-batch fermentation where one-half of the fermented material was removed at three-day intervals and replaced by fresh substrate. In this mode, protein production was 20% higher than in batch mode, protein productivity was maintained over 12 days, and sporulation was prevented.

Zusätzliches Material: 4 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/bit.260270104

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