A Mechanism for Ventricular Expansion in Communicating Hydrocephalus

This report investigates a new possible molecular mechanism for the pathogenesis of hydrocephalus. New research by Dr. Miles Johnston has found that the injection of anti beta_1 integrin antibodies into the ventricle of rats causes a drop in parenchymal pressure and causes the cerebral ventricles to enlarge which is characteristic of hydrocephalus. We investigate intramantle pressure gradients as a possible force to enlarge the ventricles and we propose a new poroelastic model incorporating the effect of the antibodies to determine if they are a possible mechanism for hydrocephalus

Functional differential equations arising in cell-growth

Non-local differential equations are notoriously difficult to solve. Cell-growth models for population growth of a cohort structured by size, simultaneously growing and dividing, give rise to a class of non-local eigenvalue problems, whose “principal” eigenvalue is the time-constant for growth/decay. These and other novel non-local problems are described and solved in special cases in this paper

A study of jet flow and reattachment in control valves

The work continues investigations into the characteristics of piston control valves; in particular it examines fluid flow through constrictions similar to the valve port. The various flow phenomena associated with piston valves are reviewed, then a closer study is made of reports examining more specific aspects of the flow including separation, jet flow reattachment and turbulent entrainment. From these reports a mathematical model of the entrainment process inside valves is constructed for incompressible flow, and predictions of reattachment bubble lengths obtained for various port geometries. Experimental results obtained using a two-dimensional model of the valve port show that the measured bubble lengths hear the same relationship to the predictions as is found in two other investigations of reattaching jet flow in similar configurations which are analysed on the same basis. A further study of reports on compressible jet flow yields three methods to predict the jet angle of compressible flow through the valve geometry, and one is used to obtain theoretical values of jet angle and thickness over a range of geometries and pressure ratios. Further experimental results, obtained from the same valve model, verify the predictions of jet angle and establish the characteristics of the compressible bubble throughout a wide range of pressure ratios and orifice dimensions During the tests several distinct patterns of supersonic flow were observed using a schlieren light system and recorded by photographing theme Prom consideration of the measurements and theoretical predictions some explanation is offered for the observed bubble behaviour and the various flow patterns. Finally the effect of these characteristics on the performance of piston valves is discussed and an attempt made' to describe previously reported valve behaviour in terms of the measured bubble flow patterns

What is the contribution of physician associates in hospital care in England? A mixed methods, multiple case study.

OBJECTIVES: To investigate the deployment of physician associates (PAs); the factors supporting and inhibiting their employment and their contribution and impact on patients' experience and outcomes and the organisation of services. DESIGN: Mixed methods within a case study design, using interviews, observations, work diaries and documentary analysis. SETTING: Six acute care hospitals in three regions of England in 2016-2017. PARTICIPANTS: 43 PAs, 77 other health professionals, 28 managers, 28 patients and relatives. RESULTS: A key influencing factor supporting the employment of PAs in all settings was a shortage of doctors. PAs were found to be acceptable, appropriate and safe members of the medical/surgical teams by the majority of doctors, managers and nurses. They were mainly deployed to undertake inpatient ward work in the medical/surgical team during core weekday hours. They were reported to positively contribute to: continuity within their medical/surgical team, patient experience and flow, inducting new junior doctors, supporting the medical/surgical teams' workload, which released doctors for more complex patients and their training. The lack of regulation and attendant lack of authority to prescribe was seen as a problem in many but not all specialties. The contribution of PAs to productivity and patient outcomes was not quantifiable separately from other members of the team and wider service organisation. Patients and relatives described PAs positively but most did not understand who and what a PA was, often mistaking them for doctors. CONCLUSIONS: This study offers new insights concerning the deployment and contribution of PAs in medical and surgical specialties in English hospitals. PAs provided a flexible addition to the secondary care workforce without drawing from existing professions. Their utility in the hospital setting is unlikely to be completely realised without the appropriate level of regulation and authority to prescribe medicines and order ionising radiation within their scope of practice

Use of ERTS-1 data in identification, classification, and mapping of salt-affected soils in California

There are no author-identified significant results in this report

Biomechanics for inclusive urban design : effects of tactile paving on older adults’ gait when crossing the street

In light of our ageing population it is important that the urban environment is easily accessible and hence supports older adults’ independence. Tactile ‘blister’ paving was originally designed to provide guidance for visually impaired people at pedestrian crossings. However, as research links irregular surfaces to falls in older adults, such paving may have an adverse effect on older people. We investigated the effects of tactile paving on older adults’ gait in a scenario closely resembling “crossing the street”. Gait analysis of 32 healthy older adults showed that tactile, as compared to smooth, paving increases the variability in timing of foot placement by 20%, thereby indicating a disturbance of the rhythmic gait pattern. Moreover, toe-clearance during the swing phase increased by 7% on tactile paving, and the ability to stop upon cue from the traffic light was compromised. These results need to be viewed under consideration of the limitations associated with laboratory studies and real world analysis is needed to fully understand their implications for urban design

Environmental Survival of Mycobacterium avium subsp. paratuberculosis in Different Climatic Zones of Eastern Australia.

The duration of survival of both the S and C strains of Mycobacterium avium subsp. paratuberculosis in feces was quantified in contrasting climatic zones of New South Wales, Australia, and detailed environmental temperature data were collected. Known concentrations of S and C strains in feces placed on soil in polystyrene boxes were exposed to the environment with or without the provision of shade (70%) at Bathurst, Armidale, Condobolin, and Broken Hill, and subsamples taken every 2 weeks were cultured for the presence of M. avium subsp. paratuberculosis. The duration of survival ranged from a minimum of 1 week to a maximum of 16 weeks, and the provision of 70% shade was the most important factor in extending the survival time. The hazard of death for exposed compared to shaded samples was 20 and 9 times higher for the S and C strains, respectively. Site did not affect the survival of the C strain, but for the S strain, the hazard of death was 2.3 times higher at the two arid zone sites (Broken Hill and Condobolin) than at the two temperate zone sites (Bathurst and Armidale). Temperature measurements revealed maximum temperatures exceeding 60°C and large daily temperature ranges at the soil surface, particularly in exposed boxes.This work was supported by the NSW sheep industry through the NSW Ovine Johne's Disease Industry Fund and the NSW Rural Assistance Authority