Bruchanalyse an Hohlgläsern

Failure analysis of hollow glasses The failure analysis is very important to clarify damages of hollow glasses. Damages of glass bottle through over pressure are very often linked with damages to persons. This is the reason why the causal research is from particular importance. Different surface characteristics of glass fragments as well as the fracture pattern give hints to the direction of the crack, the stress just before breakage and the reason of stress. A reconstruction of the bottle is a further helpful instrument for cause studies. The difference of the various characteristics of the surface will be explained. Further on there will be discussed different reasons and mechanism of fracture.     

Self-controlled case series analyses: Small-sample performance

Second-order expressions for the asymptotic bias and variance of the log relative incidence estimator are derived for the self-controlled case series model in a simplified scenario. The dependence of the bias and variance on factors such as the relative incidence and ratio of risk to observation period are studied. Small-sample performance of the estimator in realistic scenarios is investigated using simulations. It is found that, in scenarios likely to arise in practice, asymptotic methods are valid for numbers of cases in excess of 20-50 depending on the ratio of the risk period to the observation period and on the relative incidence. The application of Monte Carlo methods to self-controlled case series analyses is also discussed.     

Stoffwechselwirkungen von ω-3-Fettsäuren

Metabolic Effects of ω-3 Fatty Acids Biological effects of ω-3 fatty acids are related to their properties as structural components of cell membranes, their role as precursors of eicosanoids and their effects on lipoprotein metabolism. This is the basis for a great variety of metabolic effects, many of which of increasing medical interest. Particularly in the cardiovascular field, ω-3 fatty acids have been shown to have a wide spectrum of potentially antiatherogenic effects. Among these are the inhibition of platelet aggregation, reduction of blood viscosity, lowering of blood pressure and suppression of inflammatory reactions in the arteriosclerotic plaque. The principal actions in lipid metabolism are a reduction in triglycerides and a small increase in HDL₂. The effect on LDL-cholesterol is complex and an adverse LDL-increase may occur in particular hyperlipoproteinemias.     

Bemerkungen zum Biot-Savartschen Gesetz

Übersicht Die folgende Arbeit verfolgt u. a. auch didaktische Absichten. Das Biot-Savartsche Gesetz wird oft falsch oder mindestens sehr mißverständlich dargestellt und auch auf unzulässige Weise benutzt. Ausgangspunkt der Mißverständnisse ist die auch in vielen Lehrbüchern anzutreffende unkorrekte Aussage, man könne einem von StromI durchflossenen Linienelement ds ein magnetostatisches Feld dB [entsprechend der Gleichung (32) des folgenden Beitrags] zuordnen. Im folgenden werden derartige Aussagen untersucht und in modifizierter Form korrekt dargestellt.

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Remarks concerning the Law of Biot-Savart

Contents The following paper is at least partly of a didactic nature. The Biot-Savart law of magnetostatics is often interpreted in an illegitimate manner and consequently applied incorrectly. The source of these misunderstandings and errors is the incorrect statement that a magnetic field dB [as given by equation (32) of this paper] is caused by an electric currentI flowing along a line element ds, a statement very popular also in many textbooks. Questions related to this problem are investigated and widespread misleading statements are replaced by correct ones.

     

Isolation and DNA sequence of the STE14 gene encoding farnesyl cysteine: Carboxyl methyltransferase

We isolated a mutant defective in C-terminal farnesyl cysteine:carboxyl methyltransferase activity from a screen for mutations causing a -specific sterility. A genomic fragment was cloned from a yeast multi-copy library that restored mating. Both the cloned gene and the sterile mutation were allelic to the STE14 gene. A ste14-complementing 2·17 kb BamHI fragment subclone was sequenced and found to encode a 239 amino acid protein with a molecular weight of 27,887 Daltons. The hydrophobicity profile of the methyltransferase reveals the presence of at least five potential transmembrane domains. In comparisons of the C-terminal methyltransferase amino acid sequence with those in the PIR and Swiss protein databases, no significantly similar sequences were found nor were conserved regions from other methyltransferases present.     

Categorical ML — Category-theoretic modular programming

We consider an extension of the functional programming language Standard ML with a modular structure based upon concepts in category theory such as categories, functors, natural transformations and adjunctions. In essence, we are following the categorical imperative of considering arrows as well as objects. This is intended to enforce a certain mathematical rigour on the programmer, so that the only programs that can be expressed are those with a categorical significance. The essentially algebraic nature of category theory means that we may generate equational correctness conditions for the modular structure of programs, thus separating the correctness of individual functions from that of modules. We describe this programming language, give examples of its use, and explain how it is implemented in a type system.