3,188 research outputs found

    Nitrogen removal during summer and winter in a primary facultative WSP pond: preliminary findings from 15N-labelled ammonium tracking techniques

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    Nitrogen removal mechanisms and pathways within WSP have been the focus of much research over the last 30 years. Debates and theories postulated continue to refine our knowledge regarding the cycling and removal pathways for this important nutrient, but a succinct answer has yet to be provided for holistic nitrogen removal. In this study, two experimental runs using labelled 15N as a stable isotope tracking technique were conducted on a pilot-scale primary facultative WSP in the UK; one in the summer of 2006, and the other in the winter of 2007. An ammonium chloride (15NH4Cl) spike was prepared as the slug for each experimental run, which also contained rhodamine WT to act as a dye tracer enabling the hydraulic characteristics of the pond to be mapped. Initial results from the study are reported here, and findings are compared and contrasted. Preliminary findings reveal that a greater proportion of 15N is incorporated into the algal biomass by assimilation and subsequent release as soluble organic nitrogen in summer than in winter. 15N ammonium passes out of the system much sooner and in a much higher proportion in the winter than in summer

    Congenital Aortic Stenosis and Aneurysms

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    Due to improvements in pediatric cardio-thoracic surgery, anesthesia and diagnostics over the past decades, the number of adult patients with congenital heart disease (CHD) is growing. This causes an increasing demand in clinical practice for insight in long term outcome in both non-operated and operated adult CHD patients. Furthermore, knowledge about etiology and genetics of CHD is rapidly expanding. Every day new genes and syndromes are identified. In order to grasp the exact nature of the pathologies described in this thesis, the epidemiology of CHD and the functional anatomy of the left ventricular outflow tract and aorta will first be delineated. Thereafter, the congenital aortic disorders investigated in this thesis will be introduced individually. Finally, the aim and outline of this thesis will be presented

    “It’s like uprooting trees”: responsive treatment for a case of complex post-traumatic stress disorder following multiple rapes

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    This systematic case study documents 27 sessions of assessment and treatment with cognitive therapy of Bongi (23)who presented with major depression, posttraumatic stress disorder and borderline traits. Bongi had been raised in a punitive environment, had been raped three times, the first time at age 9, and had been in a series of abusive relationships. The treatment illustrates the importance of therapist responsiveness in addressing this kind of complex presentation, the importance of drawing on case formulation to guide the course of treatment and the range of different interventions that need to be incorporated into an integrative treatment of a complex case. Self-report measures of depression, anxiety and posttraumatic stress indicators provided evidence that the therapy contributed to positive changes and the qualitative therapy narrative gives details of the nature of some of those changes. Although treatment was not complete when Bongi moved away, Bongi herself judged that the therapy had been a valuable experience which had resulted in her feeling more alive, more confident, and better able to take care of herself

    Holographic multiverse and the measure problem

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    We discuss the duality, conjectured in earlier work, between the wave function of the multiverse and a 3D Euclidean theory on the future boundary of spacetime. In particular, we discuss the choice of the boundary metric and the relation between the UV cutoff scale xi on the boundary and the hypersurfaces Sigma on which the wave function is defined in the bulk. We propose that in the limit of xi going to 0 these hypersurfaces should be used as cutoff surfaces in the multiverse measure. Furthermore, we argue that in the inflating regions of spacetime with a slowly varying Hubble rate H the hypersurfaces Sigma are surfaces of constant comoving apparent horizon (CAH). Finally, we introduce a measure prescription (called CAH+) which appears to have no pathological features and coincides with the constant CAH cutoff in regions of slowly varying H.Comment: A minor change: the discussion of unitarity on p.9 is clarifie

    Instantons and unitarity in quantum cosmology with fixed four-volume

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    We find a number of complex solutions of the Einstein equations in the so-called unimodular version of general relativity, and we interpret them as saddle points yielding estimates of a gravitational path integral over a space of almost everywhere Lorentzian metrics on a spacetime manifold with topology of the "no-boundary" type. In this setting, the compatibility of the no-boundary initial condition with the definability of the quantum measure reduces reduces to the normalizability and unitary evolution of the no-boundary wave function \psi. We consider the spacetime topologies R^4 and RP^4 # R^4 within a Taub minisuperspace model with spatial topology S^3, and the spacetime topology R^2 x T^2 within a Bianchi type I minisuperspace model with spatial topology T^3. In each case there exists exactly one complex saddle point (or combination of saddle points) that yields a wave function compatible with normalizability and unitary evolution. The existence of such saddle points tends to bear out the suggestion that the unimodular theory is less divergent than traditional Einstein gravity. In the Bianchi type I case, the distinguished complex solution is approximately real and Lorentzian at late times, and appears to describe an explosive expansion from zero size at T=0. (In the Taub cases, in contrast, the only complex solution with nearly Lorentzian late-time behavior yields a wave function that is normalizable but evolves nonunitarily, with the total probability increasing exponentially in the unimodular "time" in a manner that suggests a continuous creation of new universes at zero volume.) The issue of the stability of these results upon the inclusion of more degrees of freedom is raised.Comment: 32 pages, REVTeX v3.1 with amsfonts. (v2: minor typos etc corrected.

    The Politics and Practice of Archaeology in Conflict

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    World Heritage & Archaeological Resource Managemen
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