BackgroundThe aim of the study is to describe the work pattern of personal care workers (PCWs) in nursing homes. This knowledge is important for staff performance appraisal, task allocation and scheduling. It will also support funding allocation based on activities.MethodsA time-motion study was conducted in 2010 at two Australian nursing homes. The observation at Site 1 was between the hours of 7:00 and 14:00 or 15:00 for 14 days. One PCW was observed on each day. The observation at Site 2 was from 10:00 to 17:00 for 16 days. One PCW working on a morning shift and another one working on an afternoon shift were observed on each day. Fifty-eight work activities done by PCWs were grouped into eight categories. Activity time, frequency, duration and the switch between two consecutive activities were used as measurements to describe the work pattern.ResultsPersonal care workers spent about 70.0% of their time on four types of activities consistently at both sites: direct care (30.7%), indirect care (17.6%), infection control (6.4%) and staff break (15.2%). Oral communication was the most frequently observed activity. It could occur independently or concurrently with other activities. At Site 2, PCWs spent significantly more time than their counterparts at Site 1 on oral communication (Site 1: 47.3% vs. Site 2: 63.5%, P = 0.003), transit (Site 1: 3.4% vs. Site 2: 5.5%, P < 0.001) and others (Site 1: 0.5% vs. Site 2: 1.8%, P < 0.001). They spent less time on documentation (Site 1: 4.1% vs. Site 2: 2.3%, P < 0.001). More than two-thirds of the observed activities had a very short duration (1 minute or less). Personal care workers frequently switched within or between oral communication, direct and indirect care activities.ConclusionsAt both nursing homes, direct care, indirect care, infection control and staff break occupied the major part of a PCW’s work, however oral communication was the most time consuming activity. Personal care workers frequently switched between activities, suggesting that looking after the elderly in nursing homes is a busy and demanding job.

Abstract.A model for drug diffusion from a spherical polymeric drug delivery device is considered. The model contains two key features. The first is that solvent diffuses into the polymer, which then transitions from a glassy to a rubbery state. The interface between the two states of polymer is modeled as a moving boundary, whose speed is governed by a kinetic law; the same moving boundary problem arises in the one-phase limit of a Stefan problem with kinetic undercooling. The second feature is that drug diffuses only through the rubbery region, with a nonlinear diffusion coefficient that depends on the concentration of solvent. We analyze the model using both formal asymptotics and numerical computation, the latter by applying a front-fixing scheme with a finite volume method. Previous results are extended and comparisons are made with linear models that work well under certain parameter regimes. Finally, a model for a multilayered drug delivery device is suggested, which allows for more flexible control of drug release.

We model the increase in temperature in compost piles due to micro-organisms undergoing exothermic reactions. The model incorporates two types of heat release: one due to biological activity; and the other due to the oxidation of cellulosic materials. In this study we also include the consumption of oxygen. We investigate the bifurcation behaviour and compare the results obtained from models that include and exclude oxygen consumption in both one-and two-dimensional geometries.

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The problem of heat and mass transfer within a porous catalytic pellet in which an irreversible first-order exothermic reaction occurs is a much-studied problem in chemical-reactor engineering. The system is described by two coupled reactiondiffusion equations for the temperature and the degree of reactant conversion. The Galerkin method is used to obtain a semi-analytical model for the pellet problem with both one-and two-dimensional slab geometries. This involves approximating the spatial structure of the temperature and reactant-conversion profiles in the pellet using trial functions. The semi-analytical model is obtained by averaging the governing partial differential equations. As the Arrhenius law cannot be integrated explicitly, the semi-analytical model is given by a system of integrodifferential equations. The semi-analytical model allows both steady-state temperature and conversion profiles and steady-state diagrams to be obtained as the solution to sets of transcendental equations (the integrals are evaluated using quadrature rules). Both the static and dynamic multiplicity of the semi-analytical model is investigated using singularity theory and a local stability analysis. An example of a stable limit cycle is also considered in detail. Comparison with numerical solutions of the governing reaction-diffusion equations and with other results in the literature shows that the semi-analytical solutions are extremely accurate.

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