543 research outputs found

    Development in aquatic humic chemistry

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    Welche landwirtschaftlichen Anbausysteme fördern das Bodenleben?

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    In einem weltweit einmaligen Langzeit-Feldexperiment in der Nähe von Basel werden seit 1978 biologische und konventionelle Anbauweisen in einer 7-jährigen Fruchtfolge miteinander verglichen. Die Landbausysteme wirken sich unterschiedlich auf das Bodenleben aus. Vor allem die biologischen Verfahren fördern die Menge, die Aktivität und die Diversität von Bodenlebewesen. Mit der Entwicklung neuer Methoden sind weitere Erkenntnisgewinne möglich geworden

    Psychotherapeutic practice in paediatric oncology: four examples

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    Psychotherapy, often used with children treated for a solid tumour, is seldom described. We present four examples of such therapies: a mother who refused enucleation for her 7-month-old boy; a boy's jealousy towards his sister who was being treated for a brain tumour; a teenager troubled by his scar; a 7-year-old boy embarrassed by the unconscious memory of his treatment when he was 5 months old. All names have been changed, for reasons of privacy. Psychotherapies aim to help children and parents to cope with the violent experience of having cancer, to recover their freedom of thought and decision-making concerning their life, their place in the family, their body image, their self-esteem, their identity. These descriptions of brief psychotherapy could help paediatricians to gain a more thorough understanding of the child's experience, to improve collaboration with psychotherapists and to confront clinical skills of psychotherapists. © 2000 Cancer Research Campaig

    Physiological modeling of isoprene dynamics in exhaled breath

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    Human breath contains a myriad of endogenous volatile organic compounds (VOCs) which are reflective of ongoing metabolic or physiological processes. While research into the diagnostic potential and general medical relevance of these trace gases is conducted on a considerable scale, little focus has been given so far to a sound analysis of the quantitative relationships between breath levels and the underlying systemic concentrations. This paper is devoted to a thorough modeling study of the end-tidal breath dynamics associated with isoprene, which serves as a paradigmatic example for the class of low-soluble, blood-borne VOCs. Real-time measurements of exhaled breath under an ergometer challenge reveal characteristic changes of isoprene output in response to variations in ventilation and perfusion. Here, a valid compartmental description of these profiles is developed. By comparison with experimental data it is inferred that the major part of breath isoprene variability during exercise conditions can be attributed to an increased fractional perfusion of potential storage and production sites, leading to higher levels of mixed venous blood concentrations at the onset of physical activity. In this context, various lines of supportive evidence for an extrahepatic tissue source of isoprene are presented. Our model is a first step towards new guidelines for the breath gas analysis of isoprene and is expected to aid further investigations regarding the exhalation, storage, transport and biotransformation processes associated with this important compound.Comment: 14 page

    Single Impurity Effects in Multiband Superconductors with Different Sign Order Parameters

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    A single impurity problem is investigated for multiband s-wave superconductors with different sign order parameters (+-s-wave superconductors) suggested in Fe-pnictide superconductors. Not only intraband but also interband scattering is considered at the impurity. The latter gives rise to impurity-induced local boundstates close to the impurity. We present an exact form of the energy of the local boundstates as a function of strength of the two types of impurity scattering. The essential role of the impurity is unchanged in finite number of impurities. The main conclusions for a single impurity problem help us understand effects of dense impurities in the +-s-wave superconductors. Local density of states around the single impurity is also investigated. We suggest impurity site nuclear magnetic resonance as a suitable experiment to probe the local boundstates that is peculiar to the +-s-wave state. We find that the +-s-wave model is mapped to a chiral dx2-y2+-idxy-wave, reflecting the unconventional nature of the sign reversing order parameter. For a quantum magnetic impurity, interband scattering destabilizes the Kondo singlet.Comment: 23 pages, 7 figures, to be published in J. Phys. Soc. Jpn. (2009) No.

    Species by Environment Interactions Affect Pyrrolizidine Alkaloid Expression in Senecio jacobaea, Senecio aquaticus, and Their Hybrids

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    We examined the effects of water and nutrient availability on the expression of the defense pyrrolizidine alkaloids (PAs) in Senecio jacobaea and S. aquaticus. Senecio jacobaea, and S. aquaticus are adapted to different natural habitats, characterized by differing abiotic conditions and different selection pressures from natural enemies. We tested if PA concentration and diversity are plastic over a range of water and nutrient treatments, and also whether such plasticity is dependent on plant species. We also tested the hypothesis that hybridization may contribute to PA diversity within plants, by comparing PA expression in parental species to that in artificially generated F1 hybrids, and also in later generation natural hybrids between S. jacobaea and S. aquaticus. We showed that total PA concentration in roots and shoots is not dependent on species, but that species determines the pattern of PA diversification. Pyrrolizidine alkaloid diversity and concentration are both dependent on environmental factors. Hybrids produce a putatively novel PA, and this PA is conserved in natural hybrids, that are backcrossed to S. jacobaea. Natural hybrids that are backcrossed several times to S. jacobaea are with regard to PA diversity significantly different from S. jacobaea but not from S. aquaticus, while F1 hybrids are in all cases more similar to S. jacobaea. These results collectively suggest that PA diversity is under the influence of natural selection

    Incidence of postoperative nausea and vomiting and associated factors in Hospital Universitario San Ignacio

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    Introducción: A pesar de los adelantos en la anestesiología actual, aún continúan presentándosenáuseas y vómito en el postoperatorio (NVPO) como una de las complicacionesmás frecuentes con una incidencia que oscila entre el 4,6 % y el 49,0 %. Objetivos:Describir la incidencia de náuseas y vómitos en el postoperatorio, e identificar posiblesfactores de riesgo y el tratamiento utilizado. Material y métodos: Se diseñó un estudioobservacional, para lo cual se recolectó información de 1191 pacientes mayores de 15años de edad, programados para procedimientos electivos. Resultados: La incidenciade NVPO encontrada fue del 8,1 %, (7,8 % para náuseas y 3,6 % para vómito) y supresentación se relacionó especialmente con el sexo femenino, cirugía laparoscópica ytiempo de anestesia mayor de 180 minutos.Artículo original11-21Introduction : Despite the current advances in anesthesiology, nausea and vomiting in post- operative (PONV) is one of the most common complications with an incidence between 4.6 and 49.0%. Objectives : To describe the inci - dence of nausea and vomiting after surgery, and identify potential risk factors and the treatment used. Methods: An observational study, with 1191 patients over 15 years of age was collected, scheduled for elective procedures. Results: The incidence of PONV was 8.1% (7.8% to 3.6% for nausea and vomiting) and its presentation is particularly associated with female sex, laparoscopic surgery and anesthesia time greater than 180 minute
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