Showing papers by "Newcastle University published in 1980"

Epidemiology of acromegaly in the newcastle region

Abstract: In an attempt to derive estimates of the incidence and prevalence of acromegaly a survey of the population in the area served by the former Newcastle Regional Hospital Board has been conducted to detect cases of acromegaly alive after 1 January 1960 and diagnosed before 31 December 1971. Cases were detected by means of letters to general practitioners, hospital physicians, neurosurgeons and to hospital records officers, as well as from death certificates. From the population of 3.1 millions a firm diagnosis of acromegaly was made in 164 patients, in eighty-one on clinical grounds alone and in eighty-three with confirmation by assay of human growth hormone (hGH). The annual incidence of acromegaly appears to be close to three cases per million and the prevalence of diagnosed cases up to forty cases per million. In male acromegalics there was a significant increase in the risk of death from cardiovascular, cerebrovascular respiratory and malignant diseases but in females from cerebrovascular disease only.

Sharing a Processor Among Many Job Classes

Abstract: . A single-server processor-sharing system with M job classes is analyzed in the steady state. The scheduling strategy considered divides the total processor capacity in unequal fractions among the different job classes. More precisely, if there are N~jobs of classj in the system, j = 1, 2 ..... M, each class k job receives a fraction gh/(~M.~ giN~) of the processor capacity. Earlier analyses of this system are shown to be incorrect and new expressions for the conditional expected response times Wk(t) of class k jobs with required service time t are obtained (for general required service time distributions). These yield the asymptotic behavior of W~(t) as t ~ oo and rather simple formulas in the exponential case. The unconditional average response times are also obtained. KEY WORDS AND PHRASES: processor sharing, strategy, egalitarian, discriminatory job classes, Laplace transform, Fourier-Stiehjes transform CR CATEGORIES: 4.35.4.6, 5.5, 6.2

The metaphase arrest technique. A critical review.

Abstract: The accuracy and precision of the stathmokinetic experiment for the determination of cell birth rate are discussed from practical and theoretical viewpoints. Topics covered include the determination of the optimal dosage of the metaphase arresting agent, the times at which observations should be taken and which cells should be counted, the correct method of estimating cell birth rate and the dependence of any derived estimate of the turnover time on the age distribution of cycling cells. Failure to consider any of these points can lead to considerable inaccuracy. It is further shown that the stathmokinetic method is a rather imprecise one for measuring the turnover time and the duration of mitosis. Data are present comparing the results of using the technique with those obtained from autoradiographic studies.

Beast and Man

Abstract: Philosophers have traditionally concentrated on the qualities that make human beings different from other species. In Beast and Man Mary Midgley, one of our foremost intellectuals, stresses continuities. What makes people tick? Largely, she asserts, the same things as animals. She tells us humans are rather more like other animals than we previously allowed ourselves to believe, and reminds us just how primitive we are in comparison to the sophistication of many animals. A veritable classic for our age, Beast and Man has helped change the way we think about ourselves and the world in which we live.

A Note on the Separation of Natural Mixtures of Bacterial Menaquinones using Reverse Phase Thin-layer Chromatography

Abstract: Natural mixtures of bacterial menaquinones were separated according to the length and degree of saturation of the polyisoprenyl side-chain using ready made Merck RP-18F254 reverse phase thin-layer chromatography plates. The system described affords a simple and rapid means of menaquinone characterization.

The regional distribution of innovative manufacturing establishments in Britain

Abstract: Oakey R. P., Thwaites A. T. and Nash P. A. (1980) The regional distribution of innovative manufacturing establishments in Britain, Reg. Studies 14, 235–253. This paper describes the results of a preliminary establishment-based survey within a larger project designed to test the hypothesis that technological change varies between the Economic Planning Regions of Britain. The results based upon information from the Queen's Award to Industry and Science Policy Research Unit Innovation Data Bank, University of Sussex, tend to support the original hypothesis. The evidence suggests that both large and small establishments in the South-East Region were more innovative than those located in other regions. These regional variations appear to be influenced more by the levels of non-production employment in each region rather than by plant size structure or regional industrial structure measured in total manufacturing employment terms.

Nature of mantle heterogeneity in the North Atlantic: evidence from deep sea drilling

Abstract: Studies of dredged and drilled samples from the North Atlantic ocean have revealed that basalts with a wide range of major and trace element compositions have been generated at the Mid-Atlantic Ridge (M.A.R.). Many of the basalts erupted between latitudes 30° and 70° N do not have the geochemical characteristics of normal mid-ocean ridge basalts (m.o.r.b.) depleted in the more-hygromagmatophile (hyg.) elements. Drilling along mantle flow lines transverse to the ridge has shown that different segments of the M.A.R. have produced basalts with a distinct compositional range for tens of millions of years. As more data have become available, the nature and scale of this variation have been established and tighter constraints can now be placed on the petrogenetic processes involved. The rare earth elements are used to test quantitatively the effects of open and closed system fractional crystallization, equilibrium partial melting (including continuous melting), zone refining and mantle mixing processes on basalt chemistry. When evaluated in terms of the more-hyg. elements, the results show that major heterogeneities must exist in the mantle sources feeding the M.A.R. Ratios of many of the more-hyg. elements remain consistent in space and time in basalts erupted at a particular ridge segment, but vary widely between different ridge segments. These ratios are not significantly modified by the processes of basalt generation. The hyg. element relations provide a major constraint on the nature of heterogeneity in the Earth’s mantle and the processes producing it. The mantle sources of anomalous ridge segments can be best explained in terms of variable veining of a hyg. element depleted host by a hyg. element enriched liquid or fluid generated by very small degrees of partial melting. Such incipient melting, as well as subduction zone processes, may be viable mechanisms for changing hyg. element ratios in the mantle source regions on the scale observed. These processes can be integrated into a model for mantle evolution which involves (1) upward migration of incipient melts to provide a hyg. element enriched source for alkali basalts and a hyg. element depleted source for normal m.o.r.b., and (2) extraction of continental crust and recycling of the depleted residue into the mantle at subduction zones. Also, some recycling of continental material into the mantle may be required to explain Pb isotope patterns.

Cadmium and calcium interactions in the freshwater amphipod Gammarus pulex

Abstract: SUMMARY. The accumulation of cadmium from an experimental medium by the freshwater amphipod Gammarus pulex is described. Much of the uptake is internal as opposed to adsorption on the body surface, and after an apparent saturation of the exoskeleton the hepatopancreas becomes an increasingly important site of cadmium storage. The haemolymph cadmium concentration reaches a high level compared with marine crustaceans, achieving a concentration factor (ratio of internal Cd/ external Cd) of 100 after about 60 h uptake. The cadmium uptake process is severely inhibited after exposure of experimental animals to 0.5 mM 2:4 Dinitrophenol, indicating the mediation of an active process. This fact together with the negative relationship between cadmium uptake rate and the calcium concentration of the animal suggests that cadmium accumulation by this species may be at least partially accounted for by a process of ‘accidental’ active cadmium uptake, with cadmium substituting for calcium on a calcium regulatory mechanism. As yet it has not been possible to establish a true stoichiometric relationship between the two metals. Although calcium influx and cadmium uptake (influx) rates are similar over a wide range of external concentrations, calcium influx is clearly inhibited by a low external ratio of cadmium to calcium. This indicates that the relationship between the two metals is far from an equimolar one and the possibility of non-competitive inhibition of calcium influx by cadmium cannot be eliminated.

Assessment of recovery of arm control in hemiplegic stroke patients. 1. Arm function tests

Abstract: In a preliminary study a group of hemiplegic patients have been assessed for return of arm function for periods up to 64 weeks after stroke. The assessment procedure employs a few simple and easily performed tests which take into account principles of the central nervous control of movement. The tests are highly repeatable and can be carried out by staff untrained in medicine or any form of physical therapy. Patients have been divided into two groups on the basis of the scores obtained in the tests at 16 weeks after stroke. The group scoring 80% or more are very likely subsequently to recover useful function of the arm and hand. The group of patients scoring less than 80% at 16 weeks after stroke are likely subsequently to recover limited arm movements and little hand movement. The preliminary results would suggest that the tasks provide a guide to prognosis and an indiction of the most suitable type of general physical therapy.

A theoretical and clinical investigation into the taper achieved on crown and inlay preparations.

Abstract: Summary The minimum angles of taper that can in theory be formed to various preparations were established for representative dental preparations and operating distances. These values were compared with the taper of dental preparations formed both under laboratory conditions and in clinical practice, the latter by measurement of taper on the dies of clinically successful crowns and inlays. A possible explanation for the discrepancy noted between recommended degrees of taper and the tapers produced under clinical conditions was considered to be due to the requirement by a dental surgeon to avoid forming undercuts to the line of withdrawal of a cast intracoronal or extracoronal retainer.

Residual stresses and aging in injection molded polypropylene

Abstract: The residual stresses in injection molded bars of polypropylene have been examined using a stress relaxation method and by the layer removal technique. A positive value for the internal stress parameter was obtained with newly molded specimens and was found to be retained by specimens stored at liquid nitrogen temperature. The stress relaxation parameter reduced to zero both for specimens aged at room temperature and also for those aged at −40°C. Nevertheless the relaxation behavior of specimens aged at all three temperatures was quite distinct. The layer removal technique showed that the stresses near to the surface were compressive and those in the interior tensile, in apparent contradiction to the interpretation of Kubat and Rigdahl for the meaning of a positive internal stress parameter. A marked reduction in stress levels on aging at room temperature was confirmed, however. The relevance of the relaxation spectrum of polypropylene to these observations is discussed.

A Recovery Cache for the PDP-11

Abstract: Backward error recovery is an integral part of the recovery block scheme that has been advanced as a method for providing tolerance against faults in software; the recovery cache has been proposed as a mechanism for providing this error recovery capability. This correspondence describes a recovery cache that has been built for the PDP-11 family of machines. This recovery cache has been designed to be an "add-on" unit which requires no hardware alterations to the host CPU but which intersects the bus between the CPU and the memory modules. Specially designed hardware enables concurrent operation of the recovery cache and the host system, and aims to minimize the overheads imposed on the host.

Histamine weal formation and absorption in man

Abstract: 1 The weal and flare response to intradermal histamine was measured over a range of doses in forearm skin of man. 2 The use of calipers to measure weal thickness was validated by measurement of observer and method errors. Repeated measurements at intervals of 5 min or more compressed the weals by 6% per reading. 3 Flare response reached a maximum at 5 min compared with 20 min for weal thickness and the sensitivity of the flare response was greater than the weal response at lower doses of histamine. 4 Sensitivity, lambda was comparable for the measurement of flare, weal diameter and thickness or volume. The advantage of weal thickness was in the measurement of weal formation and resorption. 5 The time course of histamine weal formation and disappearance was measured and found to have a T1/2 of 5.4 min and 87 min, respectively. 6 The T1/2 of disappearance of comparable 09% w/v NaCl solution and serum weals were 18 and 28 min respectively. 7 It is suggested that persistence of histamine weals is due to a vasoactive agent other than histamine.

Stability Considerations in Thermoelastic Contact

Abstract: A simple one-dimensional model is described in which thermoelastic contact conditions gioe rise to nonuniqueness of solution. The stability of the various steady-state solutions discovered is investigated using a perturbation method. The results can be expressed in terms of the minimization of a certain energy function, but the authors have so far been unable to justify the use of such a function from first principles in view of the nonconservative nature of the system.