Showing papers by "University of Glasgow published in 1992"

Application of generalized differential quadrature to solve two-dimensional incompressible navier-stokes equations

Abstract: A global method of generalised differential quadrature is applied to solve the two-dimensional incompressible Navier-Stokes equations in the vorticity-stream-function formulation. Numerical results for the flow past a circular cylinder were obtained using just a few grid points. A good agreement is found with the experimental data.

Implementing lazy functional languages on stock hardware: the Spineless Tagless G-machine

Abstract: The Spineless Tagless G-machine is an abstract machine designed to support non-strict higher-order functional languages. This presentation of the machine falls into three parts. Firstly, we give a general discussion of the design issues involved in implementing non-strict functional languages. Next, we present the STG language, an austere but recognizably-functional language, which as well as a denotational meaning has a well-defined operational semantics. The STG language is the ‘abstract machine code’ for the Spineless Tagless G-machine. Lastly, we discuss the mapping of the STG language onto stock hardware. The success of an abstract machine model depends largely on how efficient this mapping can be made, though this topic is often relegated to a short section. Instead, we give a detailed discussion of the design issues and the choices we have made. Our principal target is the C language, treating the C compiler as a portable assembler.

The control of allergens of dust mites and domestic pets: a position paper.

Abstract: *Department of Zoology, University of Glasgow, Glasgow G12 8QQ, U.K.; ^Regional Department of Respiratory Medicine, East Birmingham Hospital, Bordesley Green East, Birmingham B9 5ST, U.K.; % Respiratory Research Group, Department of Child Health, Royal Hospital for Sick Children, Bristol BS2 8BJ, U.K.; ^Medicine I, Level D, Centre Block, Southampton General Hospital, Southampton SO9 4XY, U.K.; '^Allergy Analysis Centre, 31 Station Lane, Witney, Oxfordshire OX8 6AN, U.K.; **The Blackrock Clinic, Blackrock, Co. Dublin, Republic of Ireland. ^•\Cardiothoracic Centre, Broadgreen Hospital, Liverpool L14 3LB, U.K.; ^Department of Child Health, Southampton General Hospital, Southampton S09 4XY, U.K.; ^Regional Department of Respiratory Physiology, Wythenshawe Hospital, Manchester M23 9LT, U.K.

Abnormalities of glucocorticoid metabolism and the renin—angiotensin system: a four-corners approach to the identification of genetic determinants of blood pressure

Abstract: Aim: To assess the feasibility and utility of a new method to identify factors associated with increased predisposition to high blood pressure in young peopleSubjects: Eight hundred and sixty-four people aged 16—4 years and their parentsSetting: Ladywell Medical Centre, Edinburgh, Scotland, UK. Meth

Localization of androgen receptors in human skin by immunohistochemistry: implications for the hormonal regulation of hair growth, sebaceous glands and sweat glands.

Abstract: A mouse monoclonal antibody against the N-terminal region of human androgen receptor (AR) was used to identify receptors by immunoperoxidase staining in frozen serial sections of skin from scalp, face, limb and genitalia of men and women aged 30-80 years. AR staining was restricted to cell nuclei. In sebaceous glands, AR were identified in basal and differentiating sebocytes. The percentage of receptor-positive basal sebocyte nuclei in the temple/forehead region was greater in males (65%) than in females (29%). AR staining was restricted to the cells of dermal papillae in anagen and telogen hair follicles. The percentage of dermal papillae containing AR was greater in males (58%) than in females (20%). The number of positively stained dermal papillae was lowest in female scalp skin. In 163 hair follicles sectioned, AR were absent from germinative matrix, outer root sheath (including the bulge region), inner root sheath, hair shaft and hair bulb, and from the capillaries present in some large dermal papillae. AR were present in pilosebaceous duct keratinocytes, suggesting that androgens may influence pilosebaceous duct keratinization. AR were also identified in interfollicular epidermal keratinocytes and dermal fibroblasts although, in both cell types, intensity and frequency of staining were greatest in genital skin. AR were identified in luminal epithelial cells of apocrine glands in genital skin and in certain cells of the secretory coils of eccrine sweat glands in all body sites. This study indicates that androgens regulate sebaceous gland and hair growth by acting upon two different types of target cells, the epithelial sebocytes of sebaceous glands and the mesenchymal cells of the hair follicle dermal papilla.(ABSTRACT TRUNCATED AT 250 WORDS)

Monads for functional programming.

Abstract: The use of monads to structure functional programs is de- scribed Monads provide a convenient framework for simulating eects found in other languages, such as global state, exception handling, out- put, or non-determinism Three case studies are looked at in detail: how monads ease the modication of a simple evaluator; how monads act as the basis of a datatype of arrays subject to in-place update; and how monads can be used to build parsers

Relative expression of cytochrome P450 isoenzymes in human liver and association with the metabolism of drugs and xenobiotics.

Abstract: Cytochrome P450s play a central role in the metabolism and disposition of an extremely wide range of drugs and chemical carcinogens. Individual differences in the expression of these enzymes may be an important determinant in susceptibility to adverse drug reactions, chemical toxins and mutagens. In this paper, we have measured the relative levels of expression of cytochrome P450 isoenzymes from eight gene families or subfamilies in a panel of twelve human liver samples in order to determine the individuality in their expression and whether any forms are co-regulated. Isoenzymes were identified in most cases on Western blots based on the mobility of authentic recombinant human cytochrome P450 standards. The levels of the following P450 proteins correlated with each other: CYP2A6, CYP2B6 and a protein from the CYP2C gene subfamily, CYP2E1 and a member of the CYP2A gene subfamily, CYP2C8, CYP3A3/A4 and total cytochrome P450 content. Also, the levels of two proteins in the CYP4A gene subfamily were highly correlated. These correlations are consistent with the relative regulation of members of these gene families in rats or mice. In addition, the level of expression of specific isoenzymes has also been compared with the rate of metabolism of a panel of drugs, carcinogens and model P450 substrates. These latter studies demonstrate and confirm that the correlations obtained in this manner represent a powerful approach towards the assignment of the metabolism of substrates by specific human P450 isoenzymes.

Dielectric properties of female human breast tissue measured in vitro at 3.2 GHz

Abstract: Complex permittivities of in vitro diseased and undiseased human female breast tissues have been measured at 3.2 GHz using a resonant cavity technique. Ranges of dielectric properties and water contents of these tissues are presented. Experimental data are compared with models predicted from mixture equations. Measured permittivity data lie within limits set by two-phase mixture theory, but some conductivity data are in excess of those expected for a mixture of saline and protein. At any particular microwave frequency in all tissue of a given type, the relationship between permittivity and conductivity may be parametrized using the Debye relaxation equations. For each breast tissue type a characteristic relaxation frequency was calculated and found to be lower than that of physiological saline at the same temperature. It is concluded that the dielectric relaxation of tissue water is not the only dispersive process occurring at this frequency: dielectric relaxation of bound water and the tail end of a beta-dispersion may also contribute to the dielectric properties. The similarity of the dielectric properties of benign and malignant breast tumours measured in this work suggest that in vivo dielectric imaging methods will not be capable of distinguishing them.

Correlation and prediction of dense fluid transport coefficients. I. n-alkanes

Abstract: A previously described method, based on considerations of hard-sphere theory, is used for the simultaneous correlation of the coefficients of viscosity, self-diffusion, and thermal conductivity for then-alcohols, from methanol ton-decanol, in excellent agreement with experiment, over extended temperature and pressure ranges. Generalized correlations are given for the roughness factors and the characteristic volume. The overall average absolute deviations of the experimental viscosity, self-diffusion, and thermal conductivity measurements from those calculated by the correlation are 2.4, 2.6, and 2.0%, respectively. Since the proposed scheme is based on accurate density values, a Tait-type equation was also employed to correlate successfully the density of then-alcohols. The overall average absolute deviation of the experimental density measurements from those calculated by the correlation is ±0.05%.

Structural and functional relationships among the RTX toxin determinants of gram-negative bacteria.

Abstract: The RTX (repeats in toxin) cytolytic toxins r represent a family of important virulence factors that have disseminated widely among Gram-negative bacteria. They are characterised by a series of glycine-rich repeat units at the C-terminal end of each protein. They also have other features in common. Secretion from the cell occurs without a periplasmic intermediate by a novel mechanism which involves recognition of a signal sequence at the C-terminus of the toxin by membrane-associated proteins that export the toxin directly to the outside of the cell. The structural gene for each protein encodes an inactive toxin which is modified post-translationally to an active cytotoxic form by another gene product before secretion. The genes for toxin synthesis, activation and secretion are for the most part grouped together on the chromosome and form an operon. The toxins all create pores in the cell membrane of target cells leading to eventual cell lysis and they appear to require Ca2+ for cytotoxic activity. Although the toxins have a similar mode of action, they vary in target cell specificity. Some are cytotoxic for a wide variety of eukaryotic cell types while others exhibit precise target cell specificity and are only active against leukocytes from certain host species. The characteristic glycine-rich repeat units have been identified in other exoproteins besides those with cytotoxic activity and it is likely that the novel secretory mechanism has been harnessed by a variety of pathogens to release important virulence-associated factors from the cell or to locate them on the cell surface.

Uncoupling of hypomyelination and glial cell death by a mutation in the proteolipid protein gene

Abstract: PROTEOLIPID protein (PLP; Mr 30,000) is a highly conserved major polytopic membrane protein in myelin but its cellular function remains obscure. Neurological mutant mice can often provide model systems for human genetic disorders. Mutations of the X-chromosome-linked PLP gene are lethal, identified first in the jimpy mouse1,2 and subsequently in patients with PelizaeusMerzbacher disease3,4. The unexplained phenotype of these mutations includes degeneration and premature cell death of oligodendrocytes with associated hypomyelination5. Here we show that a new mouse mutant rumpshaker6 is defined by the amino-acid substitution Ile-to-Thr at residue 186 in a membrane-embedded domain of PLP. Surprisingly, rumpshaker mice, although myelindeficient, have normal longevity and a full complement of morphologically normal oligodendrocytes7. Hypomyelination can thus be genetically separated from the PLP-dependent oligodendrocyte degeneration. We suggest that PLP has a vital function in glial cell development, distinct from its later role in myelin assembly, and that this dichotomy of action may explain the clinical spectrum8 of Pelizaeus–Merzbacher disease.

Higher-Order Functions for Parsing

Abstract: In combinator parsing, the text of parsers resembles BNF notation. We present the basic method, and a number of extensions. We address the special problems presented by white-space, and parsers with separate lexical and syntactic phases. In particular, a combining form for handling the offside rule is given. Other extensions to the basic method include an $quot;into$quot; combining form with many useful applications, and a simple means by which combinator parsers can produce more informative error messages.

Axenic cultivation and characterization of Leishmania mexicana amastigote-like forms.

Abstract: A new method is described which has made possible the long-term axenic cultivation of Leishmania mexicana amastigote-like forms in Schneider's Drosophila medium supplemented with 20% (v/v) foetal calf serum Unlike previous methods, it utilizes direct culture of parasites obtained from the lesions of infected animals rather than adaptation of promastigotes in vitro Ultrastructural (possession of megasomes), biochemical (cysteine proteinase activity and gelatin SDS-PAGE banding pattern) and infectivity (in vivo) data are presented which show the close similarity of the cultured forms to lesion amastigotes The axenically cultured forms grew optimally at a temperature of 32-33 degrees C, providing further evidence for their amastigote nature It was found that adjustment of the pH of the growth medium to 54 was required in order to retain the amastigote morphology of the cultured parasites This supports the notion that leishmanial amastigotes are acidophiles

Possible upregulation of hypothalamic 5-hydroxytryptamine receptors in patients with postviral fatigue syndrome.

Abstract: OBJECTIVE--To study the dynamic function of hypothalamic 5-hydroxytryptamine receptors in patients with postviral fatigue syndrome. DESIGN--Prospective comparison of patients with postviral fatigue syndrome with two control groups. SETTING--Department of neurology, University of Glasgow, Southern General Hospital; department of psychiatry, St James9s Hospital, Dublin. SUBJECTS--15 patients with postviral fatigue syndrome, 13 age and sex matched healthy subjects, and 13 patients with primary depression. MAIN OUTCOME MEASURES--Serum prolactin concentrations before and one, two, and three hours after administration of buspirone. RESULTS--Because of the effects of sex hormones on prolactin secretion data for men and women were analysed separately. There was no significant difference in baseline prolactin concentrations between patients with postviral fatigue syndrome and healthy subjects or those with primary depression. However, the percentage difference between peak and baseline values was significantly higher in patients with postviral fatigue syndrome than the control groups (one way analysis of variance: women, p = 0.003; men, p = 0.004). CONCLUSIONS--The results suggest upregulation of hypothalamic 5-hydroxytryptamine receptors in patients with postviral fatigue syndrome but not in those with primary depression. The buspirone challenge test may therefore be useful in distinguishing these two conditions. Larger studies are required to explore the potential value of drugs acting on central 5-hydroxytryptamine receptors in the treatment of patients with the postviral fatigue syndrome.

Audit of public education campaign to encourage earlier detection of malignant melanoma.

Abstract: OBJECTIVES--To evaluate a public campaign to encourage earlier referral and treatment of primary cutaneous malignant melanoma and thus reduce mortality related to melanoma. DESIGN--Production and distribution of educational material aimed at adults. Update information sent to general practitioners before campaign. Analysis of data on melanoma before and after campaign in June 1985. SETTING--West of Scotland, population 2.7 million. MAIN OUTCOME MEASURES--Total numbers of referrals per month to melanoma clinic, numbers of melanomas diagnosed, change in distribution of thickness, and mortality before and after introducing the campaign. RESULTS--Referrals to the pigmented lesion clinic increased by 278%, from five a week in June-July 1984 to 19 a week in June-July 1985. Twice as many women as men were referred to the clinic (49% of referrals were of women aged under 65). The numbers of newly diagnosed primary cutaneous melanoma were 63 (12/month) in January-May 1985 and 146 (21/month) in June-December 1985, an increase of 131%. The percentage of tumours detected that were less than 1.5 mm thick rose significantly by 16% (95% confidence interval 11% to 19%), from 38% (328) in 1979-84 to 54% (592) in 1985-9. Mortality began to fall in women from 1988. CONCLUSIONS--The public education campaign succeeded in reducing the absolute number of thick tumours and melanoma related mortality in women.

A review of the use and the effects of marks and devices on birds

Abstract: This paper reviews the use and the effects of marks and devices on birds. Although most papers reporting research on birds make use of marks or devices, very few studies test for harmful effects or data biases caused by these. Many research projects have used marks and devices without encountering any harmful effects of these on the birds being studied. However, where assessments have been made it is clear that all of the methods of marking can have adverse effects, while most devices attached to birds do alter their behaviour to some extent. We conclude that more attention should be given to these effects before the normal assumption of no influence on the biological parameters being studied can be made with confidence. There is a need for careful tests of the effects of marking methods to be undertaken. We hope that this review will assist people studying birds to plan their use of marks and devices in such a way as to minimize problems caused by these research tools.

Confounding in epidemiological studies: why "independent" effects may not be all they seem.

Abstract: enrolling children because we ran out ofmoney. It was only at the very last moment, at this last special legislative session, through extraordinary efforts by some really committed folks in the governor's office, that a deal was struck to expand the programme so we could reopen enrolment. The programme provides subsidised health insurance to children who do not qualify for Medicaid for primary ambulatory care-not hospital care, no medications, no high-tech procedures, just basic routine care, getting the infection treated before it turns into a major problem. It's a very narrow, circumscribed programme. But we need to expand it to all eligible children. The legislators chose children because frankly, from a political standpoint, children are easiest to sell. But as we discussed, there's so much need for expanded access to programmes like this, even before we get to comprehensive reform. It can be effective, I think, in targeting the most needy populations and solving some of the biggest inequities in the system. So I think we can push ahead with things like insurance reform as we did in this legislative sessioncommunity rating, eliminating pre-existing conditions. We can push ahead with patchwork programmes like child health. Any amount of resources we can commit to that while we're trying to deal with the larger issues-how we're going to control costs in the major programmes and expand access and make sure that quality doesn't suffer at the same time. We have to do both. So I'd look forward to a lot of beneficial changes. I'd look forward to a more enlightened AIDS policy if we get a change of administration in Washington. I would hope even ifwe don't get a change ofadministration we would get a more enlightened AIDS policy, but I don't really see much prospect of that.

Cointegration and dynamic time series models

Abstract: . This paper provides a survey of some of the recent developments in the field of econometric modelling with cointegrated time series. In particular, we describe the testing and estimation procedures which have become increasingly popular in the recent applied literature. In addition to the ‘two-stage’ procedure proposed by Engle and Granger, we consider extensions to the modelling of dynamic models with cointegrated variables, such as the estimation of models with multiple cointegration vectors, simultaneous systems, models with seasonally integrated and cointegrated variables. Furthermore, we illustrate the practical application of the techniques describes in the paper by means of a tutorial data set.

Early predictors of life‐history events: the link between first feeding date, dominance and seaward migration in Atlantic salmon, Salmo salar L.

Abstract: Previous studies have suggested that the earliest fry to emerge from a salmonid redd may have an advantage in the subsequent competition for feeding sites, partly through a ‘prior residence’ effect Here we examined whether there was any relationship between the relative date of first feeding and subsequent dominance status and growth in a sibling group of Atlantic salmon, Salmo salar L, fry Earlier-feeding fry were dominant over their later-feeding siblings (controlling for prior residence), despite not being any larger However, these early fish soon established and then maintained a size advantage This led to an increased probability of early-feeding fish migrating to sea at age 1 year (rather than 2 or more) Thus a difference of less than 1 week in the relative timing of first feeding can translate into a year's difference in the timing of migration

Issues in the cross-national assessment of health technology.

Abstract: With the growing international literature in economic evaluation and the rapid spread of new health technologies, there is a need to undertake, or at least interpret, economic evaluations on the international level. However, the ways in which cross-national differences affect the cost-effectiveness of health technologies or their evaluations have never been studied. This paper explores these issues by taking advantage of a unique situation in which the same economic evaluation of a new indication for a health technology was conducted simultaneously in four countries using an identical methodology. The study showed that if prior agreement on methods can be reached and local data applied, economic evaluations can be undertaken in a way that facilitates the extrapolation of results from country to country.

The nofib Benchmark Suite of Haskell Programs

Abstract: This position paper describes the need for, make-up of, and “rules of the game” for a benchmark suite of Haskell programs. (It does not include results from running the suite.) Those of us working on the Glasgow Haskell compiler hope this suite will encourage sound, quantitative assessment of lazy functional programming systems. This version of this paper reflects the state of play at the initial pre-release of the suite.

Resonant tunneling through the bound states of a single donor atom in a quantum well.

Abstract: We have observed a series of sharp peaks in the low-temperature I(V) characteristics of a gated 1 \ensuremath{\mu}m\ifmmode\times\else\texttimes\fi{}1 \ensuremath{\mu}m GaAs/(AlGa)As resonant tunneling diode, in which the gate is used to reduce the effective cross-sectional area from 0.7 to 0.1 \ensuremath{\mu}${\mathrm{m}}^{2}$. These peaks, which occur at voltages well below the calculated resonant threshold, show a weak dependence on temperature, magnetic field, and cross-sectional area. We argue that this subthreshold structure is due to an inhomogeneity in the device, which gives rise to a localized preferential current path, and we deduce that the spatial extent of the inhomogeneity is approximately 25 nm. The likely origin of the inhomogeneity is a background donor impurity in the quantum well.