9,831 research outputs found

    Observation and inverse problems in coupled cell networks

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    A coupled cell network is a model for many situations such as food webs in ecosystems, cellular metabolism, economical networks... It consists in a directed graph GG, each node (or cell) representing an agent of the network and each directed arrow representing which agent acts on which one. It yields a system of differential equations x˙(t)=f(x(t))\dot x(t)=f(x(t)), where the component ii of ff depends only on the cells xj(t)x_j(t) for which the arrow j→ij\rightarrow i exists in GG. In this paper, we investigate the observation problems in coupled cell networks: can one deduce the behaviour of the whole network (oscillations, stabilisation etc.) by observing only one of the cells? We show that the natural observation properties holds for almost all the interactions ff

    The role of training in IBA implementation beyond primary health care settings in the UK

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    There has been a considerable drive to encourage a wide range of professional groups to incorporate alcohol screening (or identification) and brief advice (IBA) into their everyday practice. This article aims to examine the role of training in promoting IBA delivery in contexts outside primary care and other health settings. The data are drawn mainly from a structured online survey supplemented by illustrative material from nine qualitative interviews and insights from an expert workshop. Findings support the results from other research that issues relating to role relevance and role security continue to act as barriers to professional change. Furthermore, issues of organisational commitment and organisational barriers are insufficiently addressed in strategy to promote wider use of IBA. The article concludes that development of appropriate training for alcohol IBA needs to take account of the role of IBA within a complex interactive system of related services and help seeking pathways and consider how training can contribute to changing both professional attitudes and behaviours and organisational approaches to implementing and sustaining IBA in everyday professional practice

    Delivering alcohol IBA: is there a case for mainstreaming? Insights from an expert workshop and from the published literature

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    Identification and brief advice (IBA) has been widely advocated as a cost effective intervention to address problem drinking. Evidence for the effectiveness of IBA comes largely from primary care studies. Research in pharmacies, educational settings and criminal justice settings has indicated the possibilities for successful delivery of IBA but there is little solid evidence to support mainstreaming IBA beyond core medical facilities. Furthermore, even in primary health care settings there are continuing difficulties around implementing IBA (see: Thom et al., 2014) and continuing debate about the research findings (Heather, 2014). A number of key questions around the drive towards wider implementation of IBA were debated at an expert workshop in Birmingham in November 2014. The questions debated were: 1. What are the challenges and barriers to broadening the contexts in which alcohol IBA is delivered? 2. How can these challenges and barriers be addressed? 3. Should delivery of alcohol IBA in wider contexts (mainstreaming) be a policy goal? This monograph provides insights from this expert workshop and from the published literature on theses questions

    Delivering alcohol identification and brief advice (IBA) in housing settings: a step too far or opening doors?

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    Within the UK, there is a drive to encourage the delivery of alcohol screening (or identification) and brief advice (IBA) in a range of contexts beyond primary care and hospitals where the evidence is strongest. However, the evidence base for effectiveness in non-health contexts is not currently established. This paper considers the case of housing provided by social landlords, drawing on two research studies which were conducted concurrently. One study examined the feasibility of delivering alcohol IBA in housing settings and the other the role of training in delivering IBA in non-health contexts including housing. This paper draws mainly on the qualitative data collected for both studies to examine the appropriateness and feasibility of delivering IBA in a range of social housing settings by the housing workforce. Findings suggest that while it is feasible to deliver IBA in housing settings, there are similar challenges and barriers to those already identified in relation to primary care. These include issues around role inadequacy, role legitimacy and the lack of support to work with people with alcohol problems. Results indicate that the potential may lie in focusing training efforts on specific roles to deliver IBA rather than it being expected of all staff

    Metastable Quantum Phase Transitions in a Periodic One-dimensional Bose Gas: Mean-Field and Bogoliubov Analyses

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    We generalize the concept of quantum phase transitions, which is conventionally defined for a ground state and usually applied in the thermodynamic limit, to one for \emph{metastable states} in \emph{finite size systems}. In particular, we treat the one-dimensional Bose gas on a ring in the presence of both interactions and rotation. To support our study, we bring to bear mean-field theory, i.e., the nonlinear Schr\"odinger equation, and linear perturbation or Bogoliubov-de Gennes theory. Both methods give a consistent result in the weakly interacting regime: there exist \emph{two topologically distinct quantum phases}. The first is the typical picture of superfluidity in a Bose-Einstein condensate on a ring: average angular momentum is quantized and the superflow is uniform. The second is new: one or more dark solitons appear as stationary states, breaking the symmetry, the average angular momentum becomes a continuous quantity, and the phase of the condensate can be continuously wound and unwound

    Delivering information and brief advice on alcohol (IBA) in social work and social care settings: an exploratory study

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    Social workers and practitioners working in social care are potentially key players in the prevention of alcohol-related harm and harm reduction for people using services and their carers. This requires attention to workforce development alongside the selection of appropriate tools to support prevention strategies. We report findings from a UK exploratory study into the potential of using Identification and Brief Advice (IBA) as a tool for screening and prevention in social work and social care settings. Thirty-six social workers and social care practitioners attended one of two training workshops on IBA in the South East of England. Pre and post-workshop surveys (n = 35 and n = 20, respectively) and four post-workshop focus groups (n = 36) were conducted with participants to explore the application of IBA taking into account the paradigmatic shift towards prevention and holistic approaches indicated in recent UK legislation and policy. Four themes emerged from the findings: (1) perceptions of the social work/social care role in responding to alcohol problems, (2) ethical concerns, (3) time conflicts and problems of delivering IBA and (4) the role of training. Further studies are needed to evaluate the effectiveness of motivational techniques and tools that social workers can use to promote preventative practise for alcohol-related harm. Different strategies are required to engage and support those working in social care to increase proactive engagement with problematic alcohol use in everyday practise settings

    Responses to supplementation by dairy cows given low pasture allowances in different seasons 2. Milk production

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    Two factorial experiments were designed to determine the effects of stage of lactation, and season of the year, on cow responses to supplementary feeding. These experiments were conducted over consecutive years with 128 high genetic merit multiparous Holstein-Friesian cows in early, mid and late lactation in spring, summer, autumn and winter. At each stage of lactation, and in each season of the year, cows were offered a restricted pasture allowance (25 to 35 kg dry matter (DM) per cow per day), either unsupplemented (control) or with supplement at 50 MJ metabolizable energy (ME) per cow per day in experiment 1 and 80 MJ ME per cow per day in experiment 2. The two supplements given in both years were rolled maize grain (MG) and a mixture of foods formulated to nutritionally balance the diet (BR). In experiment 2, another treatment, of a generous pasture allowance (60 to 75 kg DM per cow per day) (AP), was imposed on an additional group of early lactation cows during each season. Direct milk solids (MS) (milk fat plus milk protein) responses in experiment 1 to MG were 169, 279, 195 and 251 g MS per cow per day in spring, summer, autumn and winter, respectively, while those to BR were 107, 250, 192, 289 g MS per cow per day. In experiment 2, however, milk solids responses to both supplements during spring were slightly below the control treatment, with values similar to those in experiment 1 in summer and autumn for cows on the BR but not the MG supplement. Milk solids responses to supplementary foods were largest during seasons of the year when the quantity and quality of pasture on offer resulted in the lowest milk solids yield from unsupplemented cows. When carry-over effects of feeding MG and BR on milk solids production were detected, they were only about half the magnitude of the direct effects. Serum urea concentrations were higher in control cows than those offered MG with a similar effect for BR in all but summer in experiment 1, while serum glucose concentrations were highest in winter and lowest in summer. The most important factor influencing milk solids responses was the relative food deficit (RFD) represented by the decline in milk solids yield of the respective control groups after,changing from a generous pasture allowance to restricted allowance when the feeding treatments were imposed. Total milk solids responses (direct and carry-over) to supplements were greatest when severe food restrictions, relative to the cows' current food demand, resulted in large reductions in milk solids yield of the control groups. The RFD was the best predictor of milk solids response to supplementary foods. Therefore, it is likely that cows are most responsive to supplementary foods during or immediately after the imposition of a severe food restriction

    Responses to supplementation by dairy cows given low pasture allowances in different seasons 1. Pasture intake and substitution

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    Two factorial experiments were designed to determine the effects of stage of lactation, and season of the year, on cow responses to supplementary feeding. These experiments were conducted over consecutive years with 128 high genetic merit multiparous Holstein-Friesian cows in early, mid and late lactation in spring, summer, autumn and winter. At each stage of lactation, and in each season of the year, cows were offered a restricted pasture allowance (25 to 35 kg dry matter (DM) per cow per day), either unsupplemented (control) or supplemented with 50 MJ metabolizable energy (ME) per cow per day in experiment 1 and 80 MJ ME per cow per day in experiment 2. Two different supplements were offered, namely, rolled maize grain (MG) and a mixture of foods (BR) formulated to nutritionally balance the diet. In experiment 2, a fourth treatment consisting solely of a generous pasture allowance (60 to 75 kg DM per cow per day, AP) was introduced. Offering MG and BR increased DM intake (DMI). At the restricted pasture allowance, increasing total ME allowance (MEA) by offering supplementary foods increased ME intake (MEI) by 0.68 (s.e. 0.047) MJ per extra MJ ME offered. This highly significant (P < 0.001) linear relationship was consistent across seasons, and did not diminish at higher MEA. In experiment 2, cows in early lactation had lower substitution rates than mid and late lactation cows irrespective of season. Substitution rate was higher when higher pasture allowance or quality of pasture on offer enabled the unsupplemented cows to achieve higher DMI from pasture than at other times of the year. These results suggest that one of the key factors determining the intake response to supplementary foods is pasture allowance. Within spring calving dairying systems, the largest increases in total DMI per kg of supplement offered is likely when offering supplements to early lactation cows grazing restricted allowances of high quality pasture
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