Showing papers by "University of Huddersfield published in 1989"

Variation in lumbar sagittal mobility with low-back trouble.

Abstract: The influence of low-back trouble on lumbar sagittal mobility was explored in 958 individuals aged 10 to 84 years. Experience of low-back trouble was determined by questionnaire, and categorized as none, a previous history, or a current spell. Maximal mobility was estimated from flexicurve records of back surface curvature. The results for adults revealed that mean mobility values were reduced by both previous and current low-back trouble, particularly in the upper lumbar region, when compared with nonsufferers. Stepwise regression analyses showed that variation in mobility was best accounted for by the cumulative effects of age and sex. These variables accounted for approximately one-third of the variation in mobility: low-back trouble only accounted for an additional 1%. At the extremes of the range, both hypomobility and hypermobility were identified as risk indicators for low-back trouble. Relative hypermobility was not confined to subjects with no history of back trouble; some current sufferers had particularly high levels of mobility. Similarly hypomobility was found in nonsufferers as well as in those with back trouble. The data indicated that young adults (notably males) with previous low-back trouble may not recover their previous mobility on symptomatic resolution. The finding of hypermobility in current sufferers indicates that mobilization therapy may not be appropriate for such patients.

Prediction of Low-Back Trouble Frequency in a Working Population

Abstract: This study was performed to estimate the discriminatory power of multiple combinations of risk indicators for the occurrence and recurrence of low-back trouble (LBT) in workers. Two categories of LBT provided groups for discrimination; 1) the presence or absence of LBT history, and 2) three patterns of recurrence characterized by the number of episodes (isolated, periodic, chronic). The risk indicators comprised data reflecting occupational and leisure demands on the back, measures of lumbar sagittal mobility, and anamnestic features of the first episode. Discriminant analysis was the statistical procedure used. The results showed that it was possible to find linear combinations of the discriminating variables that successfully allocated around two-thirds of the sample to the correct group. The presence of a history of LBT was predicted by the combined effect of increasing age and adult sports participation, but only in females did a heavier job contribute to such prediction. A reduction in risk was associated with lumbar flexibility and sports participation at school. Chronic LBT was more accurately identified than the two other groups; increasing age, a long initial spell, and an onset early in life were associated with increased likelihood of chronicity, while a report of symptoms being relieved by sitting reduced this risk. It is concluded that the occurrence and recurrence of LBT are related to combinations of risk indicators, and that it is imperative to consider the interactive effect of a multiplicity of factors in epidemiologic studies.

Optical fibre digital pulse-position modulation

Abstract: A performance analysis has been presented for digital PPM transmitted over an optical fibre channel and detected using both optimum and sub-optimum pre-detection filters. Receiver sensitivity calculations, carried out at a bit-rate of 140Mbit/s and a wavelength of 1.3 μm, show that the optimum digital PPM system considered offers an 8.6 dB improvement over a typical PCM system. The sub-optimum pre-detection filters considered were a matched filter, an optimised 3-pole filter and a third-order Butterworth filter. These led to sensitivity degradations of 0.4 dB, 0.9 dB and 1.1 dB respectively. This clearly illustrates that receiver complexity can be simplified without large reductions in sensitivity. In particular, the well known and simple Butterworth filter can be employed with only 1.1 dB degradation in sensitivity. The timing requirements for digital optical fibre PPM have been analysed. An original spectral characterisation of the PPM format using its cyclostationary properties has been presented. The characterisation was used to evaluate the inherent systematic jitter associated with the extracted slot clock. An optimisation of the extracted slot clock timing variance and system wrong slot errors (due to imperfect slot synchronisation) was shown to be feasible in terms of the PLL bandwidth and the PPM order. Frame synchronisation was analysed for an original class of frame synchronisers that utilises natural sequences. The extracted frame clock timing variance was evaluated and the probability of wrong slot errors due to the non-ideal frame clock was assessed. The frame clock timing variance and wrong slot errors were shown to be minimisable provided that the proper number of natural sequences is tracked and the appropriate PLL bandwidth is utilised. The analysis has provided a performance evaluation of the optical fibre PPM system in the presence of inherent systematic slot and frame jitter.

Variable geometry turbine inlet wall mounting assembly

Abstract: A mounting assembly for a movable annular wall member of an inlet passageway of a variable geometry turbine. The inlet passageway is defined between the movable wall and a facing wall. The wall member is formed from a sheet material and is supported on a plurality of pins which extend parallel to the direction of movement of the wall member. The wall member comprises a tubular portion extending away from the facing wall and each pin supports a radial extending link. Each link is engaged in a respective slot in the tubular portion of the wall member, the links being a relatively close fit in the direction of movement of the wall member and a relatively loose fit in the circumferential direction.

Variable geometry turbine actuator assembly

Abstract: An actuator assembly for a variable geometry turbine in which an inlet passageway to the turbine is defined between a movable annular wall member and a facing wall, the position of the movable annular wall member being adjustable to control the width of the inlet passageway. The annular wall member is supported on a pair of pins which extend parallel to and are slidable parallel to the axis of the rotation of the turbine wheels. Each pin is engaged by a respective arm of a pivotally mounted stirrup the angular position of which is controlled by a single actuator. The engagement between the pins and the stirrup is such that pivotal movement of the stirrup causes axial movement of the pin.

Warlordism in China

Abstract: The Reviewis pleased to include this succinct summary of the elements defining, and the debates surrounding, the warlord phenomenon in China's history. Dr Roberts assesses the various ways in which the ‘classical’ warlordism of the period from 1916 to 1928 has been understood and interpreted. The focus is on the collapse of central state authority and the rise of provincial or regional military rulers exercising considerable power and autonomy over the locality. The paper presents a lucid account of how the origins of warlordism have been explained, what are considered to be the main characteristics of warlords and warlordism and what their effects were on the society and polity of China. A number of points raise interesting questions about the extent to which the concept might usefully be applied to some current problems in Africa. These include the decay of nationalism into regionalism and sectarianism; the extent to which such provincial power centres link up with foreign interests; the disintegration ...

Mid-Flandrian (Atlantic) landslide activity in the South Pennines

Abstract: SUMMARY Investigation of the Coldside landslide in the Vale of Edale, Derbyshire, has revealed fresh evidence of landslide activity during late Atlantic time. The toe of the landslide overlies a brown loam rich in charcoal fragments which have been radiocarbon-dated to 5860 ± 120 years BP. A radiocarbon date of 5560 ± 80 years BP obtained from basal peat in a slump depression near the top of the landslide tends to confirm pollen evidence that the likely period of landslide activity was during the late Atlantic between approximately 6000 and 5500 years BP. This coincides with the time that Mesolithic peoples had deliberately used fire for forest clearance and hunting, and the occurrence of charcoal fragments trapped beneath the landslide raises the possibility of inadvertent landscape modification by human activity in the Mesolithic.

The application of embedded transputers in a professional digital audio mixing system

Abstract: Audio mixing is an essential part of television and radio broadcasting, video post production and music recording, where the mixing console performs the majority of the audio processing tasks. Though the processing requirements are similar, each has its own special problems. The paper reviews aspects of the design of Logic 1, a transputer controlled digital mixing desk for the professional audio and broadcasting markets. Analogue mixing console technology is well-established and it was the basic requirement to combine computer control with flexible digital audio processing that led to the use of transputers.

A numerical study of turbulent flow characteristics of servo-valve orifices

Abstract: A numerical scheme based on the k—e turbulences model has been employed to determine turbulent flow characteristics of servo-valve orifices. Numerical predictions of flow patterns, flow coefficients and pressure variations within the valve orifice are presented and their implications for control of spool forces and cavitation effects are considered. The limitations of the model are considered and a proposal for more effective servo-valve modelling, together with a comparable experimental study, is made.

Building Societies as Retail Banks: The Importance of Customer Service and Corporate Image

Abstract: Legislative changes have opened up new opportunities for building societies in Britain to operate as retail banks offering a wide range of services. These organisations have operated very successfully in their traditional role for many years and have acquired a favourable generic image. The factors underlying consumer perceptions of the images of building societies are explored and compared with those relating to banks. Findings are presented to suggest that, although the building societies retain a generally favourable image, there are aspects of it that may hinder their successful operation in new markets. There is no evidence of the existence of distinct images for particular societies. Possible marketing implications of the findings are considered.

Public inquiries, legalism and child care in england and wales

Abstract: The aim of this paper is to examine the contribution of public inquiries to the reform of child care law and practice in England and Wales in the 1980s. Particular attention will be paid to the most recent inquiry, the Cleveland Report (Secretary of State, 1988). We wish to argue that a consensus has evolved on what must be done which is characterized by its reliance on what we call legalism. Evidence for this development is found both in the proposals for legal and administrative reform, and in concerns around social work practice. The reframing of child care issues around the pole of legalism is then located within the wider social and political context. Our conclusions are that ‘legalization’ may have significance in legitimating the social work profession and its role in child protection work, but that faith in legal intervention as offering a ‘solution’ to the problem of child abuse, is likely to be misplaced.

Optimal filtering of digital PPM transmitted over optical fibre channels

Abstract: The abundance in bandwidth available in the best monomode fibres may be exchanged for improved receiver sensitivity by employing digital PPM. In this paper the authors derive an optimal filter for a digital PPM coding scheme operating over a fibre channel employing a PIN-BJT receiver. Experimental results obtained at a data rate of 8 Mbit/s show that the digital PPM system offers an improvement of 4.2 dB over an equivalent binary PCM system

Stability of Feedback Control of Boost in Variable Geometry Turbocharged Automotive Diesels

Abstract: This paper is concerned with the control of turbocharged automotive diesel engines fitted with variable geometry turbines, in particular, for the case where a feedback loop is used to control the boost pressure. Interaction between the loops governing speed and controlling boost will affect the stability of the overall system.The effect of this interaction is considered for the case of automotive diesel engines in the 200–250 kW class at peak torque speed, both with and without engine speed governing, and for the cases of idle and maximum speed governing. The effects of vehicle load, turbo-charger rotor inertia and actuator response are also considered.The analysis uses the characteristic equation of the control system to determine lines of system instability in the gain plane.

The Effect of Cue-Exposure Response Prevention on Cigarette Smoking — A Single Case

Abstract: The procedure of cue-exposure response prevention has been successful in reducing subjective urges and overt behaviour associated with a number of compulsive disorders. Despite this it has not been systematically applied to the problem of smoking cessation. An individual case is presented which demonstrates the successful decrement of urges to smoke as a result of cue-exposure response prevention. The relevance of such a procedure to relapse prevention is discussed.

Decision-making in a Management Assessment Centre

Abstract: Over the years, various methods and models for the assessment of management potential have been developed. A large financial institution uses an assessment centre to determine management potential of existing staff, and information collected from the various activities carried out at the centre is used to produce an overall rating of potential. The way in which this rating is determined is examined, and it is felt that a more effective method of using the information can be developed. In order to do this, a scientific approach to the analysis of the information already collected was adopted. From the results of the analysis, and with due consideration to the non-quantitative aspects of the situation, models for determining management potential can be developed.

Law students' attitudes towards assessment

Abstract: This paper outlines the research method used in Phase II of the Law Student Assessment Project; it indicates the trend of the results and shows how they relate to the findings of Phase I of the project.(1)

Cooked egg dishes

Abstract: Salmonella in eggs hit the headlines in December 1988 and the hazard of contaminated eggs was discussed in virtually every news programme and newspaper. The problem was not wholly new: outbreaks of salmonellosis from eggs had been well documented for many years. Usually eggs which were dirty, cracked, or contaminated after breaking were used to prepare egg dishes which received no further cooking. Egg dishes such as home made mayonnaise, home made ice cream and egg nog featured prominently in published outbreaks of food borne disease.