2,705 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

    The Politics and Practice of Archaeology in Conflict

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    World Heritage & Archaeological Resource Managemen

    Arsenic mobility in the ambient sulfidic environment: Sorption of arsenic(V) and arsenic(III) onto disordered mackinawite

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    Arsenate, As(V), sorption onto synthetic iron(II) monosulfide, disordered mackinawite (FeS), is fast. As(V) sorption decreases above the point of zero surface charge of FeS and follows the pH-dependent concentration of positively charged surface species. No redox reaction is observed between the As(V) ions and the mineral surface over the time span of the experiments. This observation shows that As(V) dominantly forms an outer-sphere complex at the surface of mackinawite. Arsenite, As(III), sorption is not strongly pH-dependent and can be expressed by a Freundlich isotherm. Sorption is fast, although slower than that of As(V). As(III) also forms an outer-sphere complex at the surface of mackinawite. In agreement with previous spectroscopic studies, complexation at low As(V) and As(III) concentration occurs preferentially at the mono-coordinated sulfide edge sites. The Kd (L g−1) values obtained from linear fits to the isotherm data are ∌9 for As(V) and ∌2 for As(III). Stronger sorption of As(V) than As(III), and thus a higher As(III) mobility, may be reflected in natural anoxic sulfidic waters when disordered mackinawite controls arsenic mobility
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