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  • 1
    Electronic Resource
    Electronic Resource
    An extension of the partial credit model with an application to the measurement of change (1994)
    Springer
    Psychometrika 59 (1994), S. 177-192 
    Details
    ISSN: 1860-0980
    Keywords: Partial credit model ; Rasch model ; item response theory ; measurement of change ; assessment of treatment effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Psychology
    Notes: Abstract The partial credit model is considered under the assumption of a certain linear decomposition of the item × category parametersδ ih into “basic parameters”α j. This model is referred to as the “linear partial credit model”. A conditional maximum likelihood algorithm for estimation of theα j is presented, based on (a) recurrences for the combinatorial functions involved, and (b) using a “quasi-Newton” approach, the so-called Broyden-Fletcher-Goldfarb-Shanno (BFGS) method; (a) guarantees numerically stable results, (b) avoids the direct computation of the Hesse matrix, yet produces a sequence of certain positive definite matricesB k ,k=1, 2, ..., converging to the asymptotic variance-covariance matrix of the $$\hat \alpha _j $$ . The practicality of these numerical methods is demonstrated both by means of simulations and of an empirical application to the measurement of treatment effects in patients with psychosomatic disorders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02295182
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of poly(bisphenol-a carbonate)-graft-polystyrene via the macromonomer technique (1993)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 1627-1638 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The synthesis of poly(bisphenol-A carbonate)-graft-polystyrene with grafts of definite, predictable, nearly identical length was achieved using the macromonomer technique, i.e., copolycondensation of polystyrene macromonomers, carrying aromatic hydroxyl function, with bisphenol-A and triphosgene in pyridine/methylene chloride solution. The incorporation of the macromonomer into the polycarbonate backbone was examined both qualitatively and quantitatively. The copolycarbonate show  -  in the contrast to polystyrene/polycarbonate blends of comparable molecular weights and composition  -  only one glass transition temperature, which proved to be dependent on the polystyrene content, following the Fox equation. The title compounds exhibit reduced stress-induced birefringence compared to polycarbonate.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1993.021940610
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    YMC1, a yeast gene encoding a new putative mitochondrial carrier protein (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 9 (1993), S. 301-305 
    Details
    ISSN: 0749-503X
    Keywords: Chromosome XVI ; mitochondrial carrier ; ARO7 ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have cloned and sequenced a Saccharomyces cerevisiae gene coding for a protein with significant similarities to the mitochondrial carrier family. The gene we termed YMC1 (yeast mitochondrial carrier) is located on chromosome XVI, closely downstream of ARO7 encoding chorismate mutase.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320090310
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  • 4
    Electronic Resource
    Electronic Resource
    Changes in the size of corpora allata, in the juvenile hormone III titer in the hemolymph, and in the protein content of terminal oocytes throughout the first gonadotropic cycle in Aiolopus thalassinus (Insecta: Orthoptera: Acrididae) (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 24 (1993), S. 45-54 
    Details
    ISSN: 0739-4462
    Keywords: juvenile hormone ; t-oocyte volume ; oviposition ; corpora allata activity ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In Aiolopus thalassinus (Fabr.), the changes in the volume of the corpora allata (CA), in the concentration of juvenile hormone III (JH III) in the hemolymph, and in protein content in the terminal (t) oocytes were studied during the first gonadotropic cycle. These parameters could be better related to the volume of t-oocytes than to age after emergence. The JH III titer curve was maximum (2.9 pmol/10 μl) at an oocyte volume of 1.2 mm3. Before oviposition (days 10-16) the JH III titer decreased to 0.65 pmol/10 μl hemolyph. The increase in JH III titer reflected a period of high protein storage in the t-oocytes. The largest volume of the CA was reached at the beginning of yolk storage in the t-oocytes. The highest JH III titer did not correspond with the largest volume of CA, which occurred much earlier. © 1993 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/arch.940240105
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