995 resultados para Debye-Screening Length
Resumo:
Modelling patient flow in health care systems is vital in understanding the system activity and may therefore prove to be useful in improving their functionality. An extensively used measure is the average length of stay which, although easy to calculate and quantify, is not considered appropriate when the distribution is very long-tailed. In fact, simple deterministic models are generally considered inadequate because of the necessity for models to reflect the complex, variable, dynamic and multidimensional nature of the systems. This paper focuses on modelling length of stay and flow of patients. An overview of such modelling techniques is provided, with particular attention to their impact and suitability in managing a hospital service.
Resumo:
Due to their maternal mode of inheritance, mitochondrial markers can be regarded as almost 'ideal' tools in evolutionary studies of conifer populations. In the present study, polymorphism was analysed at one mitochondrial intron (nad 1, exon B/C) in 23 native European Pinus sylvestris populations. In a preliminary screening for variation using a polymerase chain reaction-restriction fragment length polymorphism approach, two length variants were identified. By fully sequencing the 2.5 kb region, the observed length polymorphism was found to result from the insertion of a 31 bp sequence, with no other mutations observed within the intron. A set of primers was designed flanking the observed mutation, which identified a novel sequence-tagged-site mitochondrial marker for P. sylvestris. Analysis of 747 trees from the 23 populations using these primers revealed the occurrence of two distinct haplotypes in Europe. Within the Iberian Peninsula, the two haplotypes exhibited extensive population differentiation (Phi(ST) = 0.59; P less than or equal to 0.001) and a marked geographical structuring. In the populations of central and northern Europe, one haplotype largely predominated, with the second being found in only one individual of one population.
Resumo:
Aims. To explore the perspective of midwives offering serum screening for Down’s syndrome.
Background. Previous literature has indicated that the offer and discussion of prenatal serum screening tests with women is complex, and health professionals may influence women’s decisions to accept or decline screening. Midwives are usually the key professional to offer serum screening for Down’s syndrome in the UK but their perspective is relatively neglected in the literature.
Design. An explorative qualitative interview study with 15 midwives employed in a maternity unit in Northern Ireland involved in offering prenatal screening to pregnant women. Data were collected from 1 July 2005–31 October 2005.
Methods. A focused ethnographic approach was used to explore the perspective of midwives.
Results. Midwives reported difficulty in explaining the test to women and felt unable to provide the necessary information to adequately inform women within their appointment time. The test offered (the triple test) and potential pathway of subsequent care, were identified as sources of professional and personal conflict by midwives. The expectation that midwives would provide a universal offer of Down’s syndrome serum screening but be unable to support women regarding termination of pregnancy also created dissonance.
Conclusions. The feasibility of proceeding with a universal serum screening programme for Down’s syndrome is questionable in countries which legally or culturally oppose termination of pregnancy. Professionals practising within environments such as this experience conflict in their role, which affects communication with women when discussing screening tests.
Relevance to clinical practice. As midwives are often, the primary health professional providing information to women, it is important that midwives are key participants in ongoing planning and discussions about screening policy to ensure programmes are implemented successfully.