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Abstract  

The purpose of this paper is to discuss a first-return integration process which yields the Lebesgue integral of a bounded measurable function f: IR defined on a compact interval I. The process itself, which has a Riemann flavor, uses the given function f and a sequence of partitions whose norms tend to 0. The “first-return” of a given sequence
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{bbm} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\bar x$$ \end{document}
is used to tag the intervals from the partitions. The main result of the paper is that under rather general circumstances this first return integration process yields the Lebesgue integral of the given function f for almost every sequence
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{bbm} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\bar x$$ \end{document}
.
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Abstract  

Neutron activation analyses of ground samples of safe-packing insulation have shown that dust from different sources may be differentiated by trace element content. Between 10 and 20 elements were identified in each of 54 samples, and comparison of the activation “fingerprints” offers a good prospect for positively or negatively matching two or more samples.

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Abstract  

After a formal explanation of Mayer's enthalpy balance method as applied to biological reaction rates, the history of its application is traced from Rubner's dog to accounting for the energy of muscle contraction. The introduction of microcalorimetry allowed the method generally to be used for cells in vitro and now particular emphasis can be paid to the growth of cells for the production of therapeutically-important heterologous proteins. In these systems, enthalpy balance studies contribute to defining catabolic processes, designing media, understanding the mechanisms of growth and controlling cultures using heat flux as an on-line sensor of metabolic activity.

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Abstract

This paper investigates the role of homophily and focus constraint in shaping collaborative scientific research. First, homophily structures collaboration when scientists adhere to a norm of exclusivity in selecting similar partners at a higher rate than dissimilar ones. Two dimensions on which similarity between scientists can be assessed are their research specialties and status positions. Second, focus constraint shapes collaboration when connections among scientists depend on opportunities for social contact. Constraint comes in two forms, depending on whether it originates in institutional or geographic space. Institutional constraint refers to the tendency of scientists to select collaborators within rather than across institutional boundaries. Geographic constraint is the principle that, when collaborations span different institutions, they are more likely to involve scientists that are geographically co-located than dispersed. To study homophily and focus constraint, the paper will argue in favour of an idea of collaboration that moves beyond formal co-authorship to include also other forms of informal intellectual exchange that do not translate into the publication of joint work. A community-detection algorithm for formalising this perspective will be proposed and applied to the co-authorship network of the scientists that submitted to the 2001 Research Assessment Exercise in Business and Management in the UK. While results only partially support research-based homophily, they indicate that scientists use status positions for discriminating between potential partners by selecting collaborators from institutions with a rating similar to their own. Strong support is provided in favour of institutional and geographic constraints. Scientists tend to forge intra-institutional collaborations; yet, when they seek collaborators outside their own institutions, they tend to select those who are in geographic proximity. The implications of this analysis for tie creation in joint scientific endeavours are discussed.

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Abstract  

Microcalorimeters to monitor the heat dissipation of bench-scale animal cell cultures on line and in real time require a continuous circuit between the vessel measuring heat flow rate and the bioreactor. The modifications to the transmission lines and calorimetric heat exchanger were to: (i) reverse the usual upward direction of the cell suspension in the flow vessel to downwards; (ii) install an in situ washing/cleaning facility; (iii) use low diffusivity PEEK material; and (iv) maintain thermal equilibration by water-jacketing the transmission tubing. Chemical calibration showed that there was more than a 20% difference between the physical volume and the effective thermal volume. An appropriate thermodynamic system was defined in order to permit enthalpy balance studies.

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Acta Mathematica Hungarica
Authors: Z. Buczolich, M. J. Evans, and P. D. Humke
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Abstract  

It is claimed, though not without dispute, that genetically engineered mammalian cells grow more slowly than their progenitor cells because the recombinant gene system causes a metabolic burden. This was found to be the case for CHO cells transfected with expression vectors forcytochrome b5. The slower growth was associated with lower metabolic activity measured by heat flux and mitochondrial activity (rhodamine 123 fluorescence). The calorimetric-respirometric ratio was similar for all cell types, implying that the greater fluxes of glucose and glutamine in the recombinant cells was channelled to biosynthesis. This demand probably restricted the supply of pyruvate to the mitochondria in these cells.

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Acta Mathematica Hungarica
Authors: C. L. Belna, M. J. Evans, and P. D. Humke
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Summary  

Conditional stability constants have been determined for U(IV) and U(VI) Boom Clay humic acid (BCHA) and Aldrich humic acid (AHA) complexes, under anaerobic and carbonate free conditions. The constants are needed for nuclear waste repository performance assessment purposes. The U(IV) constants were obtained by developing an approach based on the solubility product of amorphous U(OH)4. The U(VI) constants were obtained by applying the Schubert ion-exchange approach.

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