1,000 research outputs found

    An interview with Judith Edwards on child psychotherapy

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    The Consultant Psychotherapist at The Tavistock Clinic explains the history of Child Psychotherapy and walks us through the five books that have influenced her mos

    Subunit interactions within the Saccharomyces cerevisiae DNA polymerase ε (pol ε) complex - Demonstration of a dimeric pol ε

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    Saccharomyces cerevisiae DNA polymerase epsilon (pol ε) is essential for chromosomal replication. A major form of pol ε purified from yeast consists of at least four subunits: Pol2p, Dpb2p, Dpb3p, and Dpb4p. We have investigated the protein/protein interactions between these polypeptides by using expression of individual subunits in baculovirus-infected Sf9 insect cells and by using the yeast two-hybrid assay. The essential subunits, Pol2p and Dpb2p, interact directly in the absence of the other two subunits, and the C-terminal half of POL2, the only essential portion of Pol2p, is sufficient for interaction with Dpb2p. Dpb3p and Dpb4p, non-essential subunits, also interact directly with each other in the absence of the other two subunits. We propose that Pol2pzDpb2p and Dpb3pzDpb4p complexes interact with each other and document several interactions between individual members of the two respective complexes. We present biochemical evidence to support the proposal that pol ε may be dimeric in vivo. Gel filtration of the Pol2pzDpb2p complexes reveals a novel heterotetrameric form, consisting of two heterodimers of Pol2pzDpb2p. Dpb2p, but not Pol2p, exists as a homodimer, and thus the Pol2p dimerization may be mediated by Dpb2p. The pol2-E and pol2-F mutations that cause replication defects in vivo weaken the interaction between Pol2p and Dpb2p and also reduce dimerization of Pol2p. This suggests, but does not prove, that dimerization may also occur in vivo and be essential for DNA replication

    Submergence and uplift associated with the giant 1833 Sumatran subduction earthquake: Evidence from coral microatolls

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    The giant Sumatran subduction earthquake of 1833 appears as a large emergence event in fossil coral microatolls on the reefs of Sumatra's outer-arc ridge. Stratigraphic analysis of these and living microatolls nearby allow us to estimate that 1833 emergence increased trenchward from about 1 to 2 m. This pattern and magnitude of uplift are consistent with about 13 m of slip on the subduction interface and suggest a magnitude (M_w) of 8.8–9.2 for the earthquake. The fossil microatolls also record rapid submergence in the decades prior to the earthquake, with rates increasing trenchward from 5 to 11 mm/yr. Living microatolls show similar rates and a similar pattern. The fossil microatolls also record at least two less extensive emergence events in the decades prior to 1833. These observations show that coral microatolls can be useful paleoseismic and paleogeodetic instruments in convergent tectonic environments

    Controlling for exposure changes the relationship between ethnicity, deprivation and injury: an observational study of child pedestrian injury rates in London.

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    BACKGROUND: Research has suggested that inequalities in risk exposure may help explain identified ethnic inequalities in child pedestrian injury risk. However, addressing risk exposure in epidemiological research presents theoretical and methodological challenges. This article conceptualises the risk of child pedestrian injury as related to both exposure levels (the quantity of time children spend as pedestrians) and the probability of a hazard where that exposure takes place (the quality of the road environment). OBJECTIVE: To investigate the sensitivity of results on ethnic inequalities in child pedestrian injury risk in London to control for exposure and hazard levels. METHODS: Using police records of injury 2000-2009, we modelled the relationship between ethnicity, deprivation and child pedestrian injury rates in London using characteristics of the road environment to control for hazard levels and restricting the analysis to the time of the weekday morning commute (7.00-9.00 am), when most children must make a journey to school, to control for exposure levels. RESULTS: Controlling for risk exposure in this way fundamentally changed the nature of the relationship between ethnicity, deprivation and child pedestrian injury. During the time of the morning commute to school, 'Black' children were found to have higher pedestrian injury rates in the least-deprived areas. CONCLUSIONS: To inform effective strategies for reducing injury inequality, it is vital that exposure to risk is both acknowledged and considered

    Assistance at mealtimes in hospital settings and rehabilitation units for patients (>65 years) from the perspective of patients, families and healthcare professionals: a mixed methods systematic review

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    Background Malnutrition is one of the key issues affecting the health of older people (>65 years). With an aging population the problem is expected to increase further since the prevalence of malnutrition increases with age. Studies worldwide have identified that some older patients with good appetites do not receive sufficient nourishment because of inadequate feeding assistance. Mealtime assistance can enhance nutritional intake, clinical outcomes and patient experience. Objectives/Aim To determine the effectiveness of meal time assistance initiatives for improving nutritional intake and nutritional status for older adult patients (>65 years) in hospital settings and rehabilitation units. The review also sought to identify and explore the perceptions and experiences of older adult patients and those involved with their care. Design Mixed methods systematic review. Data sources A search of electronic databases to identify published studies (CINAHL, MEDLINE, British Nursing Index, Cochrane Central Register of Controlled Trials, EMBASE, PsychINFO, Web of Science (1998–2015) was conducted. Relevant journals were hand-searched and reference lists from retrieved studies were reviewed. The search was restricted to English language papers. The key words used were words that described meal time assistance for adult patients in hospital units or rehabilitation settings. Review methods The review considered qualitative, quantitative and mixed methods studies that included interventions for mealtime assistance, observed mealtime assistance or discussed experiences of mealtime assistance with staff, patients, relatives, volunteers or stakeholders. Extraction of data was undertaken independently by two reviewers. A further two reviewers assessed the methodological quality against agreed criteria. Findings Twenty one publications covering 19 studies were included. Three aggregated mixed methods syntheses were developed: 1) Mealtimes should be viewed as high priority. 2a) Nursing staff, employed mealtime assistants, volunteers or relatives/visitors can help with mealtime assistance. 2b) Social interaction at mealtimes should be encouraged. 3) Communication is essential. Conclusions A number of initiatives were identified which can be used to support older patients (>65 years) at mealtimes in hospital settings and rehabilitation units. However, no firm conclusions can be drawn in respect to the most effective initiatives. Initiatives with merit include those that encourage social interaction. Any initiative that involves supporting the older patient (>65 years) at mealtimes is beneficial. A potential way forward would be for nurses to focus on the training and support of volunteers and relatives to deliver mealtime assistance, whilst being available at mealtimes to support patients with complex nutritional needs

    The Forced van der Pol Equation II: Canards in the reduced system

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    This is the second in a series of papers about the dynamics of the forced van der Pol oscillator [J. Guckenheimer, K. Hoffman, and W. Weckesser, SIAM J. Appl. Dyn. Syst., 2 (2003), pp. 1–35]. The first paper described the reduced system, a two dimensional flow with jumps that reflect fast trajectory segments in this vector field with two time scales. This paper extends the reduced system to account for canards, trajectory segments that follow the unstable portion of the slow manifold in the forced van der Pol oscillator. This extension of the reduced system serves as a template for approximating the full nonwandering set of the forced van der Pol oscillator for large sets of parameter values, including parameters for which the system is chaotic. We analyze some bifurcations in the extension of the reduced system, building upon our previous work in [J. Guckenheimer, K. Hoffman, and W. Weckesser, SIAM J. Appl. Dyn. Syst., 2 (2003), pp. 1–35]. We conclude with computations of return maps and periodic orbits in the full three dimensional flow that are compared with the computations and analysis of the reduced system. These comparisons demonstrate numerically the validity of results we derive from the study of canards in the reduced system

    Increases of Soil C, N, and P Pools Along an Acacia Tree Density Gradient and Their Effects on Trees and Grasses

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    Nitrogen (N) fixing trees including many species of Acacia are an important though variable component of savanna ecosystems. It is known that these trees enrich the soil with carbon (C) and N, but their effect on the combined C:N:P stoichiometry in soil is less well understood. Theory suggests that they might reduce available phosphorus (P), creating a shift from more N-limited conditions in grass-dominated to more P-limited conditions in tree-dominated sites, which in turn could feed back negatively on the trees' capacity to fix N. We studied the effects of Acacia zanzibarica tree density upon soil and foliar N:P stoichiometry, and the N2-fixation rates of trees and leguminous herbs in a humid Tanzanian savanna. Foliar N:P ratios and N2-fixation rates of trees remained constant across the density gradient, whereas soil C, N and organic P pools increased. In contrast, the N:P ratio of grasses increased and N2-fixation rates of leguminous herbs decreased with increasing tree density, indicating a shift towards more P-limited conditions for the understory vegetation. These contrasting responses suggest that trees and grasses have access to different sources of N and P, with trees being able to access P from deeper soil layers and perhaps also utilizing organic forms more efficientl
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