Showing papers by "University of Manchester published in 1977"

A standardized psychiatric assessment scale for rating chronic psychotic patients.

Abstract: Simple 5-point scales are described together with the method used to study their reliability, the results of which are shown. The scales are short, easy to administer and sensitive to change, therefore particularly applicable where there is the need for screening chronic psychotic populations. Some uses for the scales are suggested.

Polynomial conserved densities for the sine-Gordon equations

Abstract: Like a number of other nonlinear dispersive wave equations the sine–Gordonequation z , xt = sin z has both multi-soliton solutions and an infinity of conserved densities which are polynomials in z , x , z , xx , etc. We prove that the generalized sine–Gordon equation z , xt = F ( z ) has an infinity of such polynomial conserved densities if, and only if, F ( z ) = A e αz + B e – αz for complex valued A, B and α ≠ 0. If F ( z ) does not take the form A e αz + B e βz there is no p. c. d. of rank greater than two. If α ≠ – β there is only a finite number of p. c. ds. If α = – β then if A and B are non-zero all p. c. ds are of even rank; if either A or B vanishes the p. c. ds are of both even and odd ranks. We exhibit the first eleven p. c. ds in each case when α = – β and the first eight when α ≠ – β . Neither the odd rank p. c. ds in the case α = – β , nor the particular limited set of p. c. ds in the case when α ≠ – β have been reported before. We connect the existence of an infinity of p. c. ds with solutions of the equations through an inverse scattering method, with Backlund transformations and, via Noether’s theorem, with infinitesimal Backlund transformations. All equations with Backlund transformations have an infinity of p. c. ds but not all such p. c. ds can be generated from the Backlund transformations. We deduce that multiple sine–Gordon equations like z , xt = sin z + ½ sin ½ z , which have applications in the theory of short optical pulse propagation, do not have an infinity of p. c. ds. For these equations we find essentially three conservation laws: one and only one of these is a p. c. d. and this is of rank two. We conclude that the multiple sine–Gordons will not be soluble by present formulations of the inverse scattering method despite numerical solutions which show soliton like behaviour. Results and conclusions are wholly consistent with the theorem that the generalized sine–Gordon equation has auto-Backlund transformations if, and only if Ḟ ( z ) – α 2 F ( z ) = 0.

Psychiatric morbidity in general practice and the community.

Abstract: The "General Health Questionnaire" was used to assess the psychiatric morbidity among 365 consecutive attenders at a general practice and to compare this with a systematic random sample of 213 patients drawn from the lists of the same practice. Those attending a general practitioner are shown to be more psychiatrically disturbed than a random sample of the practice population, and this difference remains when those attending for psychological symptoms are discounted. Various social and demographic characteristics which distinguish between those who do and those who do not attend a doctor with a given set of psychological symptoms are described.

High-temperature properties of silicate liquids: applications to the equilibration and ascent of basic magma

Abstract: High-temperature heat content measurements have been made on a series of silicate liquids, which in conjunction with published data, are used to derive partial molar heat capacities of SiO$\_{2}$, TiO$\_{2}$, Al$\_{2}$O$\_{3}$, Fe$\_{2}$O$\_{3}$, FeO, MgO, CaO, Na$\_{2}$O and K$\_{2}$O in the temperature range 1200-1650 K. Only Fe$\_{2}$O$\_{3}$ appears to be compositionally dependent, and the best evidence suggests that there is no excess heat capacity ($\overline{C}\_{p,i}$ = C$\_{p}^{\text{o}}$). In combination with calorimetric data and the effect of pressure on the fusion temperature of solid compounds, a consistent set of enthalpy, entropy and volume data have been derived for the liquid compounds CaMgSi$\_{2}$O$\_{6}$, NaAlSi$\_{3}$O$\_{8}$, KAlSi$\_{3}$O$\_{8}$, Fe$\_{2}$SiO$\_{4}$ and TiO$_{2}$. By using activities (relative to a liquid standard state) calculated at 1 bar for a range of lavas, the equilibration pressures and temperatures of lavas with a lherzolitic source material are calculated, and for basanites indicate 22-26 kbar and 1310-1360 degrees C. The regular solution formulation used in these calculations gives an estimated error of 40 degrees C and 5.7 kbar when compared to experimental equilibria. It is suggested that one of the thermal responses of ascending alkali basalt magma to engulfing cooler lherzolitic nodules could be the precipitation of megacrysts, and the calculated equilibration pressures and temperatures of the megacryst assemblagc (16-20 kbar, 1220-1240 degrees C) is in accord with this. The importance of viewing volcanic eruptions as the last stage in a sequence of chemical and thermomechanical instabilities is pointed out. Equations expressing the conservation of energy, mass and momentum on a macroscopic scale are given. The high Rayleigh numbers appropriate for even the relatively small magma volumes of erupted alkali basalts indicate turbulent flow-regimes with characteristic thermal convection velocities of the same order as nodule settling velocities. There is a significant partial melting effect in the mantle surrounding an ascending diapir if buoyancy is a significant force acting to drive the magma upwards. The effect of latent heat and convective heat losses on the thermal budget of a rising diapir has been calculated and shows the assumption of adiabaticity is often unwarranted - even for rapidly ascending magma. Finally, mass transfer rates due to convective diffusion have been calculated for all the major components in a basic silicate liquid. Integral mass exchange depends inversely on the ascent rate and is quite small for the rapidly ascending alkalic basalts.

Pupil Diameter and the Depth-of-field of the Human Eye as Measured by Laser Speckle

Abstract: Results are given for the variation in the depth-of-field with entrance pupil diameter for six subjects. The method was based on observation of a laser speckle pattern at 633 nm on the surface of a slowly rotating drum. Depth-of-field falls with pupil diameters up to ∼ 5 mm and then remains at an approximately constant value. The roles of diffraction, aberration, the Stiles-Crawford effect and of non-optical aspects of the visual system are discussed.

Probabilistic techniques in a.c. load-flow analysis

Abstract: The paper describes how the previously published formulations for an a.c. probabilistic load-flow analysis can be extended to ensure precise computation of expected values, and how these may be used to obtain more precise values of standard deviations and probability-density curves than was possible thereto. Both of the present formulations linearise the problem around the precise expected value, and one of them accounts for the coupling effect between active and reactive powers. It is shown that this coupling effect may have a significant impact on some of the voltages and reactive powers, but little effect on angles and active powers. A typical system is analysed and discussed to illustrate the increased depth of information that can be gained from these improved techniques.

The pragmatics of lexical specificity

Abstract: Mainstream linguists have now begun to take an interest in the way the formal resources of language are put to use by people in communicative situations. A powerful impulse for this awakening interest came from Grice's paper ‘The logic of conversation’; (1975). Grice's work has begun to he examined, criticized, and developed (see, for example, Wilson, 1975; Kempson, 5975), and prospects are now emerging of a much more satisfying and comprehensive picture of language at work in a communicative setting. The present paper is intended as a contribution to this developing field.

Stress-tensor conformal anomaly for scalar, spinor, and vector fields

Abstract: The conformal trace anomalies for massless scalar, "neutrino," and photon fields propagating in an arbitrary Riemannian space-time are derived. They are seen to be a consequence of the subtraction, during renormalization, of a finite term, $\ensuremath{\sim}\mathrm{ln}({m}^{2}{L}^{2})$, which violates the scale invariance of the massless theory. A general derivation of the scalar anomaly is given based on the $\ensuremath{\zeta}$-function regularization developed earlier.

Olfactory bulb ablation in the rat: behavioural changes and their reversal by antidepressant drugs.

Abstract: 1. The effects of bilateral olfactory bulbectomy, sham-operation and inducement of peripheral anosmia were studied on locomotor activity, passive avoidance acquisition and irritability. 2. Bulbectomized rats were hyperactive, deficient at learning a step-down passive avoidance response and hyperirritable. Peripheral anosmia, induced by intranasal infusion of ZnSO4 solution resulted in no behavioural changes. 3. Chronic pretreatment with amitriptyline (3 and 10 mg/kg) and a tetracyclic antidepressant mianserin (Org GB 94, 5 and 15 mg/kg) reversed the hyperactivity and reduced the learning deficit of bulbectomized rats. These drugs had no significant effects on sham-operated animals. 4. Neither amitriptyline nor mianserin reduced the exaggerated responses of bulbectomized rats to external stimuli. 5. (+)-Amphetamine (1 and 3 mg/kg) accelerated the acquisition of the passive avoidance response, greatly enhanced the locomotor activity and slightly increased the irritability score of both sham-operated and bulbectomized rats. 6. Chlorpromazine (1 and 3 mg/kg) and chlordiazepoxide (10 mg/kg) significantly reduced the acquisition, locomotor activity and irritability of experimental and control rats. 7. Lithium sulphate (1 and 3 mg/kg) had no effect on activity or irritability but produced a small impairment in acquistion of bulbectomized rats. 8. It is concluded that the reversal by antidepressant drugs of the behavioural syndrome seen after olfactory bulb ablation could constitute a new model for the detection of this group of centrally acting compounds.

The measurement of lifetimes in atoms, molecules and ions

Abstract: The field of the direct measurement of atomic and molecular lifetimes has been characterized in the past few years by the development of several new and powerful techniques and by an improving ability to control and limit the measurement inaccuracies of older techniques. The establishment of a wide range of accurate values for atomic and molecular lifetimes is now possible. This review deals with the measurement of lifetimes of atoms and molecules in the gas phase, in the range 10-10-10-5 s, and concentrates on the more accurate and promising techniques, which are grouped together according to whether their most prominent feature is the means of excitation or the interference between excited levels or the coincident detection of two decay events. Possible sources of systematic error are discussed at length and the theoretical background appropriate to the measurements is given when necessary. The techniques and their areas of applicability are compared and the likely future development of them is discussed.

The interpretation of cyclical photometric variations in certain dwarf Me-type stars

Abstract: A method of determination of parameter sets characterizing models of starspots is described. The method makes use of a systematic integral notation in the description of the darkening due to spots and optimization procedures to evaluate appropriate parameters. The method is applied to light curves of YY Gem and CC Eri. In the latter case a comparison is made with the results of Bopp and Evans's (1973) study. The physical meaning of the derived parameter set and possibly correlated effects are considered for YY Gem.

Some Comments on the Canadian Lynx Data

Abstract: SUMMARY We re-examine the annual trappings of the Canadian lynx over the years 1821-1934 (inclusive), which have been reported and analysed extensively. For some references see Elton and Nicholson (1942), Rowan (1950), Moran (1952), Hannan (1960), Kashyap (1973) and Bulmer (1974). This paper shows that an autoregressive (AR) model of order eleven provides an acceptable alternative to the more widely adopted class of models with low order AR PlUS one harmonic component.

Dose any enzyme follow the Michaelis-Menten equation?

Abstract: A literature search has been conducted to see to what extent steady-state kinetics studies in the period 1965–1976 have revealed deviations from Michaelis—Menten kinetics. It was found that over 800 enzymes have been reported as giving complex curves for a variety of reasons and a group by group classification of all these enzymes has been carried out listing all the types of variations reported and the authors' explanations. In addition, for highly complex curves, we have determined the minimum degree of the rate equation. There were very few determined attempts to demonstrate adherence to the Michaelis—Menten equation over a wide variety of experimental conditions and substrate concentration and almost invariably detailed experimental work revealed unsuspected complexities. For these reasons, it is concluded that the assumption that most enzymes follow the Michaelis—Menten equation can not be supported by an appeal to the literature.

THE PHARMACOLOGY OF ADRENERGIC NEURONAL RESPONSES IN THE CEREBRAL CORTEX: EVIDENCE FOR EXCITATORY α‐ AND INHIBITORY β‐RECEPTORS

Abstract: 1. The technique of microelectrophoresis was used to compare the actions of a range of adrenoceptor agonists on single cortical neurones in the rat anaesthetized with halothane. 2. Phenylephrine and methoxamine were exclusively excitatory, whereas salbutamol was entirely depressant. Noradrenaline and isoprenaline could evoke both excitatory and depressant responses. Lower doses of isoprenaline usually evoked depressions, whereas higher doses, on the same cell, evoked excitatory responses. 3. The alpha-adrenoceptor blocking agents, phentolamine and phenoxybenzamine, reversibly antagonized excitatory responses to adrenoceptor agonists, without affecting depressant responses to adrenoceptor agonists or excitatory responses to acetylcholine. 4. The beta-adrenoceptor blocking agents, propranolol and sotalol, reversibly antagonized both depressant and excitatory responses to adrenoceptor agonists, without affecting responses to acetylcholine. When the effect of sotalol on excitatory and depressant responses to adrenoceptor agonists was compared on the same cell, the depressant responses could be selectively antagonized, without affecting the excitatory responses. 5. It is concluded that (a) responses of cortical neurones to adrenoceptor agonists are mediated by both alpha- and beta-receptors; (b) these alpha- and beta-receptors give rise to opposite effects: the alpha-receptors being excitatory and the beta-receptors being inhibitory; and (c) responses of many neurones reflect the presence of both types of receptor.

Do central dopamine receptors have a physiological role in thermoregulation

Abstract: 1 Core and tail skin temperature was measured in rats which had guide cannulae implanted into their brains to allow drug injections directly into the preoptic anterior hypothalamus. 2 Apomorphine and dopamine (10 microgram in 1 microliter) injected into the area of the preoptic anterior hypothalamus caused a fall in core temperature which was preceded by a rise in tail skin temperature. 3 The decrease in core temperature following central injection of either apomorphine or dopamine was significantly reduced by pretreating rats for 2 h with pikozide 0.5 mg/kg i.p.). 4 Bilateral intrahypothalamic injection of pimozide (0.5 microgram in 1 microliter) significantly reduced the hypothermic effect of systemic apomorphine (1.25 mg/kg i.p.). 5 Control rats placed 65 cm below a 250 W infrared lamp responded with vasodilation of tail skin blood vessels as indicated by an increase in tail skin temperature. Pimozide pretreatment (0.5 mg/kg i.p.) significantly reduced this response. 6 These results suggest that the preoptic anterior hypothalamus contains dopamine receptors which mediate hypothermia in rodents and raise the possibility that endogenous dopamine has a physiological role in thermoregulation.