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Patterns Used (pattern + used)

Distribution by Scientific Domains

Medical Sciences	40%

Selected Abstracts

Stream macroinvertebrate occurrence along gradients in organic pollution and eutrophication

FRESHWATER BIOLOGY, Issue 7 2010
NIKOLAI FRIBERG
Summary 1.,We analysed a large number of concurrent samples of macroinvertebrate communities and chemical indicators of eutrophication and organic pollution [total-P, total-N, NH4,N, biological oxygen demand (BOD5)] from 594 Danish stream sites. Samples were taken over an 11-year time span as part of the Danish monitoring programme on the aquatic environment. Macroinvertebrate communities were sampled in spring using a standardised kick-sampling procedure whereas chemical variables were sampled six to 24 times per year per site. Habitat variables were assessed once when macroinvertebrates were sampled. 2.,The plecopteran Leuctra showed a significant negative exponential relationship (r2 = 0.90) with BOD5 and occurred at only 16% of the sites with BOD5 above 1.6 mg L,1. Sharp declines with increasing BOD5 levels were found for the trichopteran families Sericostomatidae and Glossosomatidae although they appeared to be slightly less sensitive than Leuctra. Other plecopterans such as Isoperla showed a similar type of response curve to Leuctra (negative exponential) but occurred at sites with relatively high concentrations of BOD5 up to 3,4 mg L,1. In contrast, the response curve of the isopod Asellus aquaticus followed a saturation function reaching a plateau above 3,4 mg L,1 BOD5 and the dipteran Chironomus showed an exponential increase in occurrence with increasing BOD5 concentration. 3.,Macroinvertebrate occurrence appeared to be related primarily to concentrations of BOD5, NH4,N and total-P whereas there were almost no relationships to total-N. Occurrence of a number of taxa showed a stronger relationship to habitat conditions (width and substrate) than chemical variables. 4.,Important macroinvertebrate taxa are reduced at concentrations of BOD5 that are normally perceived as indicating unimpacted stream site conditions. Our results confirmed sensitivity/tolerance patterns used by existing bioassessment systems only to some degree. [source]

Clinical Practice Guideline Implementation Strategy Patterns in Veterans Affairs Primary Care Clinics

HEALTH SERVICES RESEARCH, Issue 1p1 2007
Sylvia J. Hysong
Background. The Department of Veterans Affairs (VA) mandated the system-wide implementation of clinical practice guidelines (CPGs) in the mid-1990s, arming all facilities with basic resources to facilitate implementation; despite this resource allocation, significant variability still exists across VA facilities in implementation success. Objective. This study compares CPG implementation strategy patterns used by high and low performing primary care clinics in the VA. Research Design. Descriptive, cross-sectional study of a purposeful sample of six Veterans Affairs Medical Centers (VAMCs) with high and low performance on six CPGs. Subjects. One hundred and two employees (management, quality improvement, clinic personnel) involved with guideline implementation at each VAMC primary care clinic. Measures. Participants reported specific strategies used by their facility to implement guidelines in 1-hour semi-structured interviews. Facilities were classified as high or low performers based on their guideline adherence scores calculated through independently conducted chart reviews. Findings. High performing facilities (HPFs) (a) invested significantly in the implementation of the electronic medical record and locally adapting it to provider needs, (b) invested dedicated resources to guideline-related initiatives, and (c) exhibited a clear direction in their strategy choices. Low performing facilities exhibited (a) earlier stages of development for their electronic medical record, (b) reliance on preexisting resources for guideline implementation, with little local adaptation, and (c) no clear direction in their strategy choices. Conclusion. A multifaceted, yet targeted, strategic approach to guideline implementation emphasizing dedicated resources and local adaptation may result in more successful implementation and higher guideline adherence than relying on standardized resources and taxing preexisting channels. [source]

Theme-oriented discourse analysis of medical encounters

MEDICAL EDUCATION, Issue 6 2005
Celia Roberts
Approach, Theme-oriented discourse analysis looks at how language constructs professional practice. Recordings of naturally occurring interactions are transcribed and combined with ethnographic knowledge. Analytic themes drawn primarily from sociology and linguistics shed light on how meaning is negotiated in interaction. Detailed features of talk, such as intonation and choice of vocabulary, trigger inferences about what is going on and being talked about. These affect how interactants judge each other and decisions are made. Interactions also have larger rhetorical patterns used by both patients and doctors to persuade each other. Examples, Two settings are used to illustrate this approach: genetic counselling and primary care consultations in multilingual areas. In genetic counselling, interactions are organised around the tension between the risks of knowing and the risks of occurrence. This can lead to a ,rhetorical duel' between health professionals and patients and their families. In intercultural primary care settings, talk itself may be the problem when interpretive processes cannot be taken for granted. Even widely held models of good practice can lead to misunderstandings under these conditions. Conclusion, Through discourse analysis, the talk under scrutiny can be slowed down to show the interpretive processes and overall patterns of an activity. Discourse analysts and health professionals, working together, can look at problems in new ways and develop interventions and tools for a better understanding of communication in medical life. [source]

Application of LQ modelling and optimization in urban traffic control

OPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 6 2003
Majura F. Selekwa
Abstract The increasing congestion on urban streets demands traffic control signal timing to be well co-ordinated and optimized even during the transition between timing patterns used in different periods of time-of-day (TOD). The TOD timing plans, defined by fixed-time co-ordination parameters, need to change from one TOD period to another. The current methods used in transitioning are aimed at achieving quick transition rather than optimizing traffic flow during the transition period. As a result, they generally cause increased vehicle delays during the transition period particularly for vehicles on the minor street, which face lengthened red times. This paper proposes a quadratic optimization method that can be used to reduce disutility measures to motorists during the transition period. The transition is modeled as a linear dynamic process, and the disutility measures are modeled as the sum of squares of the deviations of the co-ordination parameters,that is, cycle length, phase split, and offset,from the optimal values during the transition. A linear quadratic (LQ) optimization technique of optimal control is used to determine the step size and the number of steps necessary to complete the transition with minimum disutility. The proposed transition period optimization method has the advantage that the user need not specify minimum and maximum cycle length to achieve optimization, as is the case with current methods. Simulation results for three co-ordinated intersections showed that the proposed method reduces total vehicle delay when compared to the ,immediate' transition method embedded in CORSIM traffic simulation software. This is due to the fact that vehicles on the minor street approaches get proportional green time without significantly affecting green times on the major street approach green phase. However, the method showed a slight increase in total delay for vehicles on the major street. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Do mean-field dynamos in nonrotating turbulent shear-flows exist?

ASTRONOMISCHE NACHRICHTEN, Issue 4 2006
G. Rüdiger
Abstract A plane-shear flow in a fluid with forced turbulence is considered. If the fluid is electrically-conducting then a mean electromotive force (EMF) results even without basic rotation and the magnetic diffusivity becomes a highly anisotropic tensor. It is checked whether in this case self-excitation of a large-scale magnetic field is possible (so-called W, × J, -dynamo) and the answer is NO. The calculations reveal the cross-stream components of the EMF perpendicular to the mean current having the wrong signs, at least for small magnetic Prandtl numbers. After our results numerical simulations with magnetic Prandtl number of about unity have only a restricted meaning as the Prandtl number dependence of the diffusivity tensor is rather strong. If, on the other hand, the turbulence field is strati.ed in the vertical direction then a dynamo-active , -effect is produced. The critical magnetic Reynolds number for such a self-excitation in a simple shear flow is slightly above 10 like for the other , but much more complicated , flow patterns used in existing dynamo experiments with liquid sodium or gallium. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]