Showing papers by "University of York published in 1989"

Lectures on Macroeconomics

Abstract: Lectures on Macroeconomics provides the first comprehensive description and evaluation of macroeconomic theory in many years. While the authors' perspective is broad, they clearly state their assessment of what is important and what is not as they present the essence of macroeconomic theory today. The main purpose of Lectures on Macroeconomics is to characterize and explain fluctuations in output, unemployment and movement in prices. The most important fact of modern economic history is persistent long term growth, but as the book makes clear, this growth is far from steady. The authors analyze and explore these fluctuations. Topics include consumption and investment; the Overlapping Generations Model; money; multiple equilibria, bubbles, and stability; the role of nominal rigidities; competitive equilibrium business cycles, nominal rigidities and economic fluctuations, goods, labor and credit markets; and monetary and fiscal policy issues. Each of chapters 2 through 9 discusses models appropriate to the topic. Chapter 10 then draws on the previous chapters, asks which models are the workhorses of macroeconomics, and sets the models out in convenient form. A concluding chapter analyzes the goals of economic policy, monetary policy, fiscal policy, and dynamic inconsistency. Written as a text for graduate students with some background in macroeconomics, statistics, and econometrics, Lectures on Macroeconomics also presents topics in a self contained way that makes it a suitable reference for professional economists.

Linkage of a prion protein missense variant to Gerstmann–Sträussler syndrome

Abstract: Gerstmann-Straussler syndrome is a rare familial neurodegenerative condition that is vertically transmitted, in an apparently autosomal dominant way. It can also be horizontally transmitted to non-human primates and rodents through intracerebral inoculation of brain homogenates from patients with the disease. The exact incidence of the syndrome is unknown but is estimated to be between one and ten per hundred million. Patients initially suffer from ataxia or dementia and deteriorate until they die, in one to ten years. Protease-resistant prion protein (PrP) and PrP-immunoreactive amyloid plaques with characteristic morphology accumulate in the brains of these patients. Current diagnostic criteria for Gerstmann-Straussler syndrome incorporate clinical and neuropathological features, as animal transmission studies can be unreliable. PrP is implicated in the pathogenesis and transmission of the condition and in scrapie, an equivalent animal disease. It was discovered by enriching scrapie-infected hamster brain fractions for infectivity. Because there is compelling evidence that the scrapie isoform of PrP is a necessary component of the infectious particle, it seemed possible that the PrP gene on the short arm of human chromosome 20 in Gerstmann-Straussler syndrome might be abnormal. We show here that PrP codon 102 is linked to the putative gene for the syndrome in two pedigrees, providing the best evidence to date that this familial condition is inherited despite also being infectious, and that substitution of leucine for proline at PrP codon 102 may lead to the development of Gerstmann-Straussler syndrome.

A double‐hurdle model of cigarette consumption

Abstract: This paper shows the importance of the double-hurdle approach for modelling individuals' cigarette consumption, using data from the UK General Household Survey, and argues that participation and consumption should be treated as separate individual choices. The likelihood function for the full double-hurdle is derived, and it is shown how restrictions on the stochastic specification of the model and auxillary information, which identifies ex-smokers, allow it to be decomposed. The empirical results highlight the value of the sample separation information and the need to model starting and quitting as separate decisions.

High-resolution (1.5 Å) crystal structure of phospholipase C from Bacillus cereus

Abstract: BOTH the phosphatidylinositol-hydrolysing and the phos-phatidylcholine-hydrolysing phospholipases C have been implicated in the generation of second messengers in mammalian cells1,2. The phosphatidylcholine-hydrolysing phospholipase C(PLC) from Bacillus cereus, a monomeric protein containing 245 amino-acid residues3, is similar to some of the corresponding mammalian proteins4. This, together with the fact that the bacterial enzyme can mimic the action of mammalian PLC in causing, for example, enhanced prostaglandin biosynthesis5, suggests that B. cereus PLC can be used as a model for the hitherto poorly characterized mammalian PLCs. We report here the three-dimensional structure of B. cereus PLC at 1.5 A resolution. The enzyme is an all-helix protein belonging to a novel structural class and contains, at least in the crystalline state, three Zn2+ in the active site. We also present preliminary results from a study at 1.9 A resolution of the complex between PLC and inorganic phosphate (Pi) which indicate that the substrate binds directly to the metal ions.

The normative economics of health care finance and provision

Abstract: Whereas in many countries the 'crisis' in medical care has been seen in terms of 'excess' spending on health services, in the UK it has been seen (at least by most of those who manage and work in the NHS) as a crisis of 'underfunding' This has come about as the result of the government's successful attempts to restrain the rate of growth of real spending on the NHS, which in turn reflects the government's belief that its principal effective weapon against what it perceives to be inefficiency in the NHS is to challenge management (itself reformed and to some extent liberated) by systematic financial squeezes The same concern has given rise to a host of proposals for reform of the NHS most of which involve a much greater role for private insurance, private finance of other kinds (such as out-of-pocket payments), and private provision of health care itself

Phenol stabilizes more helix in a new symmetrical zinc insulin hexamer

Abstract: SINCE insulin was first shown by Scott to crystallize in the presence of zinc ions in 1934, a variety of Zn-containing insulin crystals have been grown. The structures of insulin in the related rhombohedral crystals of 2Zn-insulin and 4Zn-insulin have been solved and reveal that the molecule is a hexamer, organized as three dimers, each containing a 2-fold symmetry axis and held together by Zn ions. In 2Zn-insulin the hexamer is nearly symmetrical with the two axial Zn ions and the two molecules of the dimer related closely by a local 2-fold axis. But in 4Zn-insulin the two molecules in the dimer differ remarkably, creating an asymmetric 4Zn-hexamer in which one trimer is essentially equivalent to that in 2Zn-insulin and the other is different by virtue of an additional stretch of N-terminal helix between residues B1 and B8 (refs 6, 7). We report here the structure of a new symmetrical hexamer, in which all six molecules have the B1-B8 helix seen in 4Zn-insulin. Phenol molecules, found bonding specifically to each molecule, evidently stabilize this new helical conformation.

Detection of H 3 + on Jupiter

Abstract: SINCE their detection in the high latitudes of Jupiter, first by the Voyager Ultraviolet Spectrometer (UVS) experiment1,2, then by the International Ultraviolet Explorer (IDE) satellite3, the auroral particle precipitations have been associated with various phenomena in the jovian environment. In the magnetosphere, the H+3 ion, probably of ionospheric origin, was detected in situ by the Voyagers4. Infrared emissions were observed in spectral bands characteristic of CH4 (ref. 5) and of other hydrocarbons6,7, localized in two auroral spots5,8. Here we present high-resolution spectra at a wavelength of 2 μm, in the southern auroral region of Jupiter, recorded at the Canada–France–Hawaii Telescope (CFHT), which we believe to be the first astronomical spectroscopic detection of H3+. The derived rotational temperature of H3+ is in the range 1,000–1,200 K. Such strong H3+ lines could be used in future ground-based monitoring of the jovian auroral activity and to search for this molecular ion in the interstellar medium.

Evolution of yields from populations with age-specific cropping

Abstract: Age-specific exploitation of a natural population acts as a selective force on genetic variation in life history traits. Evolution arising from this selection may bring about evolutionary changes in the total yield which the population is able to sustain. An analysis of this process is given for a harvested population with densitydependent recruitment, in which selection of life history traits by cropping is independent of density and frequency. Evolution of the total yield depends on an interplay between the yield from an individual over the course of its life and recruitment; whether the total yield increases or decreases depends on the properties of particular populations. Evolution brought about by harvesting does not, in general, lead to the maximization of the total yield. Nonetheless, by appropriate choice of an age-specific harvest pattern, it is possible in principle to select the life history which gives the maximum total yield following evolution; this harvest pattern is called the ‘evolutionarily stable optimal harvesting strategy’ (ESOHS). Results of the analysis are illustrated with data on the Arcto-Norwegian cod.

The cost of diabetes.

Abstract: This paper estimates the cost of diabetes in England and Wales in 1984 to be in excess of 259.5 million pounds. The costing methodology used follows the 'cost of illness' framework. This framework defines three elements for costing: direct, indirect and psychological, although the latter element is left out of the calculation because monetary valuations for this element have never been adequately estimated. Direct costs include resources used to prevent, detect, and treat diabetes. Indirect costs relate to the loss of productive output caused by absenteeism, early retirement, and premature mortality. The estimate which has been obtained is likely to be an underestimate because of the weaknesses and gaps in the data sets. The estimate of the total lost earnings from diabetes varied greatly according to the choice of absentee rate. If there was no significant difference between absenteeism in the diabetic community and the non-diabetic community then the cost of diabetes would be 259.5 million pounds. If on the other hand the diabetic community was prone to three times as much absenteeism as the non-diabetic community then the cost of diabetes would rise to 602.5 million pounds. The costs of diabetes as a subsidiary diagnosis are extremely difficult to identify. They have been estimated in this study to be 86 million pounds but this is thought to be an overestimate. Nevertheless the cost of diabetes is significant and thus the search for more efficient treatment regimens may reduce such costs as well as enhance the quality of life of the patients concerned.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporal logic for real-time systems

Abstract: points of the classical control theory which is based on the frequency domain description of the plant, so that the H-infinity control theory has been actively studied in the recent years. It is the design method in the frequency domain based on the modern control theory. However, the H-infinity theory at the present time lacks the identification of the frequency domain. The topics treated here are, therefore, very interesting for the users intending to apply the H-infinity control theory, too. The topics also include an application to test civil engineering structures. All chapters contain the sections of 'Outline and Learning Objectives', 'Summary', 'Problems', and 'Notes and References', so that one can read this book very easily even without being acquainted with self-tuning systems. A variety of examples in the book may help the reader's understanding of the self-tuning systems. Now, open the jewelry box with your own hand. About the reviewer Seiichi Shin received degrees of Bachelor, Master, and Doctor of Engineering all from University of Tokyo, in 1978, 1980, and 1987, respectively. From 1980 to 1988, he worked at the University of Tokyo, as an associate researcher in the former, and as an assistant professor in the latter. He became an associate professor of Institute of Information Sciences and Electronics, University of Tsukuba in 1988. In April 1992, he moved to the Department of Mathematical Engineering and Information Physics, University of Tokyo. His main interest is research on control theory and its application. It includes adaptive control, time delay systems, nonlinear systems, neural network, and distributed control systems. He is a member of IEEE, SICE, ISCIE, IEE of Japan, Japan SIAM, and JSME.

On the spatial spread of the grey squirrel in Britain.

Abstract: We present a diffusion-competition model to describe the interaction between the externally introduced grey squirrel and the indigenous red squirrel in Britain. We estimate the model parameters from field data. Solution of the model predicts waves of grey squirrel invasion with speed of invasion typical of that observed in the field. Numerical solution of the model on a two-dimensional domain gives population distributions qualitatively similar to those observed. We suggest that competition alone could account for the observed displacement of the red squirrel by the grey in large regions of Britain. The solutions are qualitatively similar to those for a single species spreading in the absence of competition. The quantitative difference is because competition slows down the speed of advance of the invading species.

The structure of the saccharide-binding site of concanavalin A.

Abstract: A complex of concanavalin A with methyl alpha-D-mannopyranoside has been crystallized in space group P212121 with a = 123.9 A, b = 129.1 A and c = 67.5 A. X-ray diffraction intensities to 2.9 A resolution have been collected on a Xentronics/Nicolet area detector. The structure has been solved by molecular replacement where the starting model was based on refined coordinates of an I222 crystal of saccharide-free concanavalin A. The structure of the saccharide complex was refined by restrained least-squares methods to an R-factor value of 0.19. In this crystal form, the asymmetric unit contains four protein subunits, to each of which a molecule of mannoside is bound in a shallow crevice near the surface of the protein. The methyl alpha-D-mannopyranoside molecule is bound in the C1 chair conformation 8.7 A from the calcium-binding site and 12.8 A from the transition metal-binding site. A network of seven hydrogen bonds connects oxygen atoms O-3, O-4, O-5 and O-6 of the mannoside to residues Asn14, Leu99, Tyr100, Asp208 and Arg228. O-2 and O-1 of the mannoside extend into the solvent. O-2 is hydrogen-bonded through a water molecule to an adjacent asymmetric unit. O-1 is not involved in any hydrogen bond and there is no fixed position for its methyl substituent.

Loss of memory for people following temporal lobe damage.

Abstract: A 40-yr-old woman, K.S., is reported, who shows a severe loss of memory for people following a history of epilepsy and right anterior temporal lobectomy. Despite this memory problem, K.S. is not clinically amnesic, has a Memory Quotient of 122 on the Wechsler Memory Scale in line with her IQ of 119, and performs well on conventional tests of recognition and recall. She does not have a generalized semantic memory deficit for living things, but her deficit extends beyond people to include famous animals, buildings and product names. Autobiographical memory is good, except where memory for people is concerned. The nature of the memory store that is impaired in K.S. is discussed, as are the implications of her case for theories of the organization of long-term memory.

Acquired Equivalence and Distinctiveness of Cues

Abstract: In Experiments 1 and 2, rats received initial training in which two stimuli (A and N) were either followed by the same consequence (food) or by different consequences (food and no food). Subsequently N was paired with electric shock and the generalization of conditioned suppression to A was assessed. Suppression to A was more marked when A and N had both been followed by food than when they had had different outcomes. In Experiment 3, 3 stimuli (A, B, and N) were presented initially. For one group, A and N were paired with food and B was nonreinforced; for a second group, B was paired with food and A and N were nonreinforced. Generalization of suppression was found to be more substantial to A than to B for both groups. These results indicate that the extent to which stimuli are treated as being equivalent is partly determined by their reinforcement histories. The observation that a conditioned response that has been established to one stimulus will also be elicited, to some extent, by other stimuli is known as stimulus generalization. A widely held interpretation of this phenomenon relies on the assumption that the presentation of a stimulus will unconditionally excite a number of representational elements. It is supposed that though some of these elements (unique elements) will be activated only by the trained stimulus itself, others (common elements) will be activated by a range of stimuli (see, e.g., Atkinson & Estes, 1963; Mackintosh, 1974; Rescorla, 1976). To the extent that two stimuli excite common elements, animals will perceive them as alike and will respond to them in similar ways. This analysis provides a ready explanation of stimulus generalization and of a range of other phenomena (Rescorla, 1976).

Genetic localization of foraging (for): a major gene for larval behavior in Drosophila melanogaster.

Abstract: Localizing genes for quantitative traits by conventional recombination mapping is a formidable challenge because environmental variation, minor genes, and genetic markers have modifying effects on continuously varying phenotypes. We describe "lethal tagging," a method used in conjunction with deficiency mapping for localizing major genes associated with quantitative traits. Rover/sitter is a naturally occurring larval foraging polymorphism in Drosophila melanogaster which has a polygenic pattern of inheritance comprised of a single major gene (foraging) and minor modifier genes. We have successfully localized the lethal tagged foraging (for, 2-10) gene by deficiency mapping to 24A3-C5 on the polytene chromosome map.

Spousal violence among alcoholic women as compared to a random household sample of women

Abstract: The purpose of this study is to examine the relationship between spousal violence and women's alcoholism problems This study compares two samples: (1) 45 alcoholic women selected from local treatment agencies and Alcoholics Anonymous groups and (2) 40 nonalcoholic women selected randomly from households Two-hour interview schedules were administered to both samples The Conflict Tactics Scale was used to assess spouse-to-woman violence Alcoholic women were found to have higher levels of spouse-to-woman negative verbal interaction, moderate violence and severe violence as compared to the household women Multivariate analyses revealed that spouse violence scores were strong predictors of type of sample This was true even after controlling for presence of alcohol problems in the spouse, income, parental violence, parental alcohol problems and changes in parental family These findings suggest that alcoholism treatment programs should screen for spousal violence among women alcoholics and that victims of spousal violence should be screened for alcohol-related problems

Circular vection as a function of the relative sizes, distances, and positions of two competing visual displays

Abstract: In studies where it is reported that illusory self-rotation (circular vection) is induced more by peripheral displays than by central displays, eccentricity may have been confounded with perceived relative distance and area. Experiments are reported in which the direction and magnitude of vection induced by a central display in the presence of a surround display were measured. The displays varied in relative distance and area and were presented in isolation, with one moving and one stationary display, or with both moving in opposite directions. A more distant display had more influence over vection than a near display. A central display induced vection if seen in isolation or through a ‘window’ in a stationary surrounding display. Motion of a more distant central display weakened vection induced by a nearer surrounding display moving the other way. When the two displays had the same area their effects almost cancelled. A moving central display nearer than a textured stationary surround produced vection in...

A longitudinal case study of developmental phonological dyslexia

Abstract: We present a four-year follow-up study of JM, a developmental phonological dyslexic previously described by Snowling, Stackhouse, and Rack (1986). JM has made some progress in reading and spelling although these skills remain severely impaired. His reading and spelling skills are consistent with arrest in the logographic phase of literacy development as described by Frith (1985); reading errors are primarily visual, he is severely impaired in reading non-words, and his spelling errors are predominantly dysphonetic. In contrast to these severe decoding problems, his semantic and syntactic skills are excellent, and reading comprehension is consistently better than accuracy. He shows a range of deficits in phonological skills. He has severe impairment of output phonology, as evidenced by difficulties in repeating words and nonwords and systematic mispronunciations in his spontaneous speech. Naming skills are impaired and he has severely impaired verbal short-term memory skills. It is argued that JM'...

Promoting the well-being of working parents: Coping, social support, and flexible job schedules

Abstract: The associations of individual coping efforts, social support from four sources, and flexibility of job schedules with the well-being of working parents were examined. Full-time employees with children were sampled from eight firms and state agencies that varied in the flexibility they allowed in scheduling job hours. The 644 respondents, who completed a self administered questionnaire at their work sites, included 208 married fathers, 287 married mothers, and 149 single mothers. Individual coping was the most powerful predictor of outcomes, with problem-focused coping associated with positive outcomes and emotion-focused coping associated with negative outcomes. The generally weaker effects of social support varried according to both the donor of support and the outcome domain. Perceived flexibility in scheduling was weakly related to outcomes, but formal flexitime programs were unrelated.

Ultracytochemical characterization of anionic sites in the wall of brain capillaries.

Abstract: The chemical nature of anionic sites located on both fronts of the endothelial cells (ECs) and in the basement membrane (BM) of mouse brain capillaries was studied using tissue sections embedded in Lowicryl K4M and cationic colloidal gold. Before labelling with cationic probe, the sections were digested with the following enzymes: trypsin, papain, pronase E, proteinase K, collagenase, chondroitinase ABC, hyaluronidase, heparinase, heparitinase, neuraminidase and endoglycosidase H.