7,374 research outputs found

    Species identity dominates over environment in shaping the microbiota of small mammals

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    The mammalian gut microbiota is considered pivotal to host fitness, yet the determinants of community composition remain poorly understood. Laboratory studies show that environmental factors, particularly diet, are important, while comparative work emphasises host genetics. Here, we compare the influence of host genetics and the environment on the microbiota of sympatric small mammal species (mice, voles, shrews) across multiple habitats. While sharing a habitat caused some microbiota convergence, the influence of species identity dominated. In all three host genera examined, an individual's microbiota was more similar to conspecifics living elsewhere than to heterospecifics at the same site. Our results suggest this species‐specificity arises in part through host‐microbe codiversification. Stomach contents analysis suggested that diet also shapes the microbiota, but where diet is itself influenced by species identity. In this way, we can reconcile the importance of both diet and genetics, while showing that species identity is the strongest predictor of microbiota composition

    Signs of deterioration in infants discharged home following congenital heart surgery in the first year of life: a qualitative study

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    AIMS: To describe the ways in which parents recognise and make decisions about their child's symptoms following discharge home after congenital heart interventions in the first year of life and their experiences of seeking help. METHODS: This was a qualitative study involving semistructured interviews with parents. Twenty-one parents were recruited to the study. Parents all had a child who had congenital heart surgery in their first year of life between September 2009 and October 2013 at one of three UK cardiac centres; the children had either died or were readmitted as an emergency following initial discharge. RESULTS: Some parents were unable to identify any early warning signs. Others described symptoms of deterioration including changes in feeding and appearance, respiratory distress and subtle behavioural changes that may not be routinely highlighted to parents at discharge. Several barriers to accessing prompt medical assistance were identified including parents feeling that their concerns were not taken seriously, long wait times and lack of protocols at A&E. CONCLUSIONS: Our study highlights behavioural symptoms as being a potentially underemphasised sign of deterioration and identifies a number of barriers to parents accessing support when they are concerned. It is important that parents are encouraged to seek advice at the earliest opportunity and that those health professionals at the front line have access to the information they need in order to respond in an appropriate and timely way. A role for home monitoring was also noted as potentially useful in identifying at risk children who appear clinically well

    Why, what, and how? case study on law, risk, and decision making as necessary themes in built environment teaching

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    The paper considers (and defends) the necessity of including legal studies as a core part of built environment undergraduate and postgraduate curricula. The writer reflects upon his own experience as a lawyer working alongside and advising built environment professionals in complex land remediation and site safety management situations in the United Kingdom and explains how themes of liability, risk, and decision making can be integrated into a practical simulation in order to underpin more traditional lecture-based law teaching. Through reflection upon the writer's experiments with simulation-based teaching, the paper suggests some innovations that may better orientate law teaching to engage these themes and, thereby, enhance the relevance of law studies to the future needs of built environment professionals in practice.</p

    The explanation of unexpected temperature dependence of the muon catalysis in solid deuterium

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    It is shown that due to the smallness of the inelastic cross-section of the dΌd\mu-atoms scattering in the crystal lattice at sufficiently low temperatures the ddΌdd\mu-mesomolecules formation from the upper state of the hyperfine structure dΌ(F=3/2)d\mu (F=3/2) starts earlier than the mesoatoms thermolization. It explains an approximate constancy of the ddΌdd\mu-mesomolecule formation rate in solid deuterium.Comment: 6 pages, 2 jpeg-figure

    Research encounters, reflexivity and supervision

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    Reflexivity in qualitative and ethnographic social science research can provide a rich source of data, especially regarding the affective, performative and relational aspects of interviews with research subjects. This paper explores by means of three case examples different ways of accessing and using such reflexivity. The examples are drawn from an empirical psycho-social study into the identity transitions of first-time mothers in an inner-city multicultural environment. Fieldnotes and supervision were used to engage with researcher subjectivity, to enhance the productive use of reflexivity and to address the emotional work of research. The methodology of the supervision was psychoanalytic, in its use of a boundaried frame and of psychoanalytic forms of noticing oneself, of staying engaged emotionally as well as creating a reflective distance. The examples illustrate how this can enhance the knowledge gained about the research subjects

    Resonant Formation of dÎŒtd\mu t Molecules in Deuterium: An Atomic Beam Measurement of Muon Catalyzed dt Fusion

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    Resonant formation of dÎŒtd\mu t molecules in collisions of muonic tritium (ÎŒt\mu t) on D2_2 was investigated using a beam of ÎŒt\mu t atoms, demonstrating a new direct approach in muon catalyzed fusion studies. Strong epithermal resonances in dÎŒtd\mu t formation were directly revealed for the first time. From the time-of-flight analysis of 2036±1162036\pm 116 dtdt fusion events, a formation rate consistent with 0.73±(0.16)meas±(0.09)model0.73\pm (0.16)_{meas} \pm (0.09)_{model} times the theoretical prediction was obtained. For the largest peak at a resonance energy of 0.423±0.0370.423 \pm 0.037 eV, this corresponds to a rate of (7.1±1.8)×109(7.1 \pm 1.8) \times 10^9 s−1^{-1}, more than an order of magnitude larger than those at low energies.Comment: To appear in Phys. Rev. Let

    Spectral Statistics of Erd{\H o}s-R\'enyi Graphs II: Eigenvalue Spacing and the Extreme Eigenvalues

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    We consider the ensemble of adjacency matrices of Erd{\H o}s-R\'enyi random graphs, i.e.\ graphs on NN vertices where every edge is chosen independently and with probability p≡p(N)p \equiv p(N). We rescale the matrix so that its bulk eigenvalues are of order one. Under the assumption pN≫N2/3p N \gg N^{2/3}, we prove the universality of eigenvalue distributions both in the bulk and at the edge of the spectrum. More precisely, we prove (1) that the eigenvalue spacing of the Erd{\H o}s-R\'enyi graph in the bulk of the spectrum has the same distribution as that of the Gaussian orthogonal ensemble; and (2) that the second largest eigenvalue of the Erd{\H o}s-R\'enyi graph has the same distribution as the largest eigenvalue of the Gaussian orthogonal ensemble. As an application of our method, we prove the bulk universality of generalized Wigner matrices under the assumption that the matrix entries have at least 4+Ï”4 + \epsilon moments

    Patients' Experience of therapeutic footwear whilst living at risk of neuropathic diabetic foot ulceration: an interpretative phenomenological analysis (IPA).

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    BACKGROUND: Previous work has found that people with diabetes do not wear their therapeutic footwear as directed, but the thinking behind this behaviour is unclear. Adherence to therapeutic footwear advice must improve in order to reduce foot ulceration and amputation risk in people with diabetes and neuropathy. Therefore this study aimed to explore the psychological influences and personal experiences behind the daily footwear selection of individuals with diabetes and neuropathy. METHODS: An interpretative phenomenological analysis (IPA) approach was used to explore the understanding and experience of therapeutic footwear use in people living at risk of diabetic neuropathic foot ulceration. This study benefited from the purposive selection of a small sample of four people and used in-depth semi structured interviews because it facilitated the deep and detailed examination of personal thoughts and feelings behind footwear selection. FINDINGS: Four overlapping themes that interact to regulate footwear choice emerged from the analyses: a) Self-perception dilemma; resolving the balance of risk experienced by people with diabetes and neuropathy day to day, between choosing to wear footwear to look and feel normal and choosing footwear to protect their feet from foot ulceration; b) Reflective adaption; The modification and individualisation of a set of values about footwear usage created in the minds of people with diabetes and neuropathy; c) Adherence response; The realignment of footwear choice with personal values, to reinforce the decision not to change behaviour or bring about increased footwear adherence, with or without appearance management; d) Reality appraisal; A here and now appraisal of the personal benefit of footwear choice on emotional and physical wellbeing, with additional consideration to the preservation of therapeutic footwear. CONCLUSION: For some people living at risk of diabetic neuropathic foot ulceration, the decision whether or not to wear therapeutic footwear is driven by the individual 'here and now', risks and benefits, of footwear choice on emotional and physical well-being for a given social context

    Controlling the accuracy of the density matrix renormalization group method: The Dynamical Block State Selection approach

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    We have applied the momentum space version of the Density Matrix Renormalization Group method (kk-DMRG) in quantum chemistry in order to study the accuracy of the algorithm in the new context. We have shown numerically that it is possible to determine the desired accuracy of the method in advance of the calculations by dynamically controlling the truncation error and the number of block states using a novel protocol which we dubbed Dynamical Block State Selection (DBSS). The relationship between the real error and truncation error has been studied as a function of the number of orbitals and the fraction of filled orbitals. We have calculated the ground state of the molecules CH2_2, H2_2O, and F2_2 as well as the first excited state of CH2_2. Our largest calculations were carried out with 57 orbitals, the largest number of block states was 1500--2000, and the largest dimensions of the Hilbert space of the superblock configuration was 800.000--1.200.000.Comment: 12 page

    Correlation effects in ionic crystals: I. The cohesive energy of MgO

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    High-level quantum-chemical calculations, using the coupled-cluster approach and extended one-particle basis sets, have been performed for (Mg2+)n (O2-)m clusters embedded in a Madelung potential. The results of these calculations are used for setting up an incremental expansion for the correlation energy of bulk MgO. This way, 96% of the experimental cohesive energy of the MgO crystal is recovered. It is shown that only 60% of the correlation contribution to the cohesive energy is of intra-ionic origin, the remaining part being caused by van der Waals-like inter-ionic excitations.Comment: LaTeX, 20 pages, no figure
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