The role of analysis in an age of computers: view from theanalytical side

The role of both past and current analysis in computer-based electromagnetics research is examined. Some observations on the current status of computer-based solutions are presented. It is concluded that analysis will remain an essential tool for making discoveries of electromagnetic phenomena, for providing physical insight into complex phenomena, and for the development of robust problem formulations and numerical methods, so that computed results with verifiable accuracy can be achieved. It is also concluded that more attention to verifying the accuracy of numerical results obtained from computer solutions is needed     

Staff Scheduling with Day-Off and Workstretch Constraints

A day-off scheduling problem is analyzed, in which the objective is to minimize the total workforce size necessary to meet a given daily requirement for staff and subject to constraints involving frequency of weekends off and length of work tours. By exploring special structure in the problem, we deduce a flexible, modular technique for building optimal schedules.     

Profiles in discouragement: two studies of variability in the time course of smoking withdrawal symptoms

A mouse homolog of the Drosophila Disabled (dab) gene, disabled-1 (mdab1), encodes an adaptor molecule that functions in neural development. Targeted disruption of the mdab1 gene (mdab1-1 mice) leads to anomalies in the development of the cerebrum, hippocampus, and cerebellum. Here we describe a number of histologic abnormalities in the cerebellum of the mdab1-1 mouse. There is a complete absence of foliation, and most Purkinje cells are clumped in central clusters. However, lamination appears to develop normally in areas where the Purkinje cells and external granular layer are closely apposed. The granular layer forms a thin rind over most of the cerebellar surface, but is subdivided by both transverse and parasagittal boundaries. The Purkinje cells, identified by anti-zebrin II in the adult or anti-calbindin in the new born mdab1-1 mutant cerebellum, form a parasagittal banding pattern, similar to but distorted compared with the wild-type design. The data suggest that the development of the mdab1-1 cerebellum parallels the development of reeler. The reeler gene encodes an extracellular protein (Reelin) that is secreted by the external granular layer. Because Reelin expression is retained in the mdab1-1 mutant mouse, mDab1 p80 may act in a parallel pathway or downstream of Reelin, leading to the transformation of embryonic Purkinje cell clusters into the adult parasagittal bands.     

Information capacity of the stationary Gaussian channel

The averaged information capacity of the mismatched stationary continuous-time Gaussian channel is considered, in the limit as the observation time becomes infinite. It is required only that the signal satisfy a reproducing kernel Hilbert space constraint on expected energy. This requires the, signal energy to be distributed in regions where the noise energy, is not too small, and is the weakest condition that provides finite capacity. In the case when both the noise covariance and the filter on the message are expressed by rational functions, the results complement those previously obtained by Gallager and Holsinger (1968), and the combination gives a complete solution to the capacity problem. The treatment provides a desirable generality on the class of transmitted signals that is not present in previous treatments     

The set of all minimal partial realizations

This paper is concerned with the uniqueness of minimal partial realizations. Earlier papers are typically concerned with the problem of the existence and the determination of a matrix triple(tilde{A},tilde{B},tilde{C})which is a minimal partial realization of a sequence{Y_{1},...,Y_{m}}of Markov parameters. In this paper a parameterized realization(A(y),B, C)(yis a parameter vector) is defined which characterizes the set of all minimal partial realizations of the sequence{ Y_{1},. . . , Y_{m}}. An example is provided and the utility of the parameterization is discussed.     

The effect of heat-treatment and nitrogen addition on the critical current density of a worked niobium 44 wt % titanium superconducting alloy

Mechanical working of a single phase superconducting alloy leads to an increase in the critical current density,J _c, After cold-rollingJ _c exhibits anisotropy as the angle of the magnetic field to the rolled surface is changed. This paper studies the effects of interstitial addition and heat-treatment onJ _c and its anisotropy in both cold-rolled and wire-drawn alloy. The variations inJ _c are correlated with the observed changes in the microstructure.     

Changes in the pituitary-testicular system with age

In order to provide a comprehensive account of pituitary-testicular function in man, 466 subjects, ranging in age from 2 to 101 years, were studied to examine blood levels of the pituitary gonadotrophins (LH and FSH), the sex steroids testosterone and oestradiol, the binding capacity of the sex hormone binding globulin (SHBG), the free testosterone and oestradiol fractions, and the transfer constant for the peripheral conversion of testosterone to oestradiol. The results were compared with clinical indices of testicular size, sexual function and secondary sex hair distribution. Serum LH and FSH were low before puberty, increased in pubertal adolescents to levels somewhat above those of adults and subsequently increased progressively over the age of 40 years. Testosterone levels fell slowly after the age of 40, while there was a slight rise in plasma oestradiol with increasing age. FSH and testosterone showed small seasonal variations in young adult men, the lowest values being seen in winter. SHBG binding capacity was high in two prepubertal boys, fell in adult men, but increased in old age. Free testosterone and oestradiol levels fell in old age. The metabolic clearance rates (MCR) of testosterone and oestradiol also fell in old age, while the conversion of testosterone to oestradiol was increased. Many correlations were observed between various hormonal and clincial measurements. The evidence is consistent with a primary decrease in testicular function over the age of 40 years.