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Efforts to address the information management problems of physicians include the Cochran reviews of the effectiveness of health care interventions and international clinical practice guidelines. A better theoretical base is needed to guide the choice of effective dissemination strategies. (Contains 18 references.) (SK)

New multiscale research datasets were acquired in central Saskatchewan, Canada during February 2003 to quantity the effect of spatially heterogeneous land cover and snowpack properties on passive microwave snow water equivalent (SWE) retrievals. Microwave brightness temperature data at various spatial resolutions were acquired from tower and airborne microwave radiometers, complemented by spaceborne Special Sensor Microwave/Imager (SSM/I) data for a 25 x 25 km study area centerd on the Old Jack Pine tower in the Boreal Ecosystem Research and Monitoring Sites (BERMS). To best address scaling issues, the airborne data were acquired over an intensively spaced grid of north-south and east-west oriented flight lines. A coincident ground sampling program characterized in situ snow cover for all representative land cover types found in the study area. A suite of micrometeorological data from seven sites within the study area was acquired to aid interpretation of the passive microwave brightness temperatures. The in situ data were used to determine variability in SWE, snow depth, and density within and between forest stands and land cover types within the 25 x 25 km SSM/I grid cell. Statistically significant subgrid scale SWE variability in this mixed forest environment was controlled by variations in snow depth, not density. Spaceborne passive microwave SWE retrievals derived using the Meteorological Service of Canada land cover sensitive algorithm suite were near the center of the normally distributed in situ measurements, providing a reasonable estimate of the mean grid cell SWE. A realistic level of SWE variability was captured by the high-resolution airborne data, showing that passive microwave retrievals are capable of capturing stand-to-stand SWE variability if the imaging footprint is sufficiently small. Index Terms--Microwave radiometry, scaling, snow water equivalent (SWE).

Snow water equivalent (SWE) is a critical parameter for climatological and hydrological studies over northern high-latitude areas. In this paper, we study the usability of the Helsinki University of Technology (HUT) snow emission model for the estimation of SWE in a Canadian boreal forest environment. The experimental data (airborne passive microwave and ground-based data) were acquired during the Boreal Ecosystem-Atmosphere Study winter field campaign held in February 1994 in Central Canada. Using the experimental dataset, surface brightness temperatures at 18 and 37 GHz (vertical polarization) were simulated with the HUT snow emission model and compared to those acquired by the airborne sensors. The results showed an important underestimation at 37 GHz (-27 K) and an overestimation at 18 GHz (10 K). In this paper, we demonstrate that the errors in the model simulations are due mainly to the extinction coefficient modeling, which is a function of snow grain size. Therefore, we propose a new semiempirical function for the extinction coefficient, based on an empirical correction to the Rayleigh scattering expression. Results presented in this paper show that the proposed function improves the HUT model accuracy to predict brightness temperature in the experimental context considered, with a mean error of [+ or -] 5 K and [+ or -] 9 K, respectively, at 18 and 37 GHz, and a negligible bias (less than 4 K) in both cases. These errors are comparable in magnitude to the accuracy of the radiometers used during the airborne flights. SWE was retrieved using the modified HUT snow emission model based on an iterative inversion technique. SWE was estimated with a mean error of [+ or -] 10 mm and a negligible bias. Only a rough knowledge of mean snow grain size [phi] was required in the inversion procedure. The effects of possible errors on mean snow grain size [phi] are presented and discussed. Index Terms--Boreal Ecosystem-Atmosphere Study (BOREAS), Boreal forest, microwave radiometry, snow emission model, snow water equivalent (SWE).

Vertically polarized 18-, 19-, and 37-GHz brightness temperatures from the Scanning Multichannel Microwave Radiometer (SMMR) and Special Sensor Microwave/Imager (SSM/I) are examined for the August 2-20, 1987 period when data from both sensors are available in the Equal-Area Scalable Earth Grid (EASE-Grid) projection. Colocated measurements over terrestrial surfaces of central North America are compared because of a previously observed inconsistency in derived winter season snow water equivalent across the cross-platform passive microwave time series. The results of this comparison show that SSM/I brightness temperatures systematically exceed SMMR measurements, with the magnitude of this difference dependant on overpass time and brightness temperature magnitude. Regression relationships are determined for adjusting EASE-Grid SMMR data to an SSM/I F8 baseline and are compared to the results of a previous study that examined daily averaged data for the polar regions. These results suggest that adjustment factors are not globally applicable; rather the region and application must be considered. Index Terms--Brightness temperatures, passive microwave, Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave/Imager (SSM/I).

Abstract Background There is growing interest in the use of cognitive, behavioural, and organisational theories in implementation research. However, the extent of use of theory in implementation research is uncertain. Methods We conducted a systematic review of use of theory in 235 rigorous evaluations of guideline dissemination and implementation studies published between 1966 and 1998. Use of theory was classified according to type of use (explicitly theory based, some conceptual basis, and theoretical construct used) and stage of use (choice/design of intervention, process/mediators/moderators, and post hoc/explanation). Results Fifty-three of 235 studies (22.5%) were judged to have employed theories, including 14 studies that explicitly used theory. The majority of studies (n = 42) used only one theory; the maximum number of theories employed by any study was three. Twenty-five different theories were used. A small number of theories accounted for the majority of theory use including PRECEDE (Predisposing, Reinforcing, and Enabling Constructs in Educational Diagnosis and Evaluation), diffusion of innovations, information overload and social marketing (academic detailing). Conclusions There was poor justification of choice of intervention and use of theory in implementation research in the identified studies until at least 1998. Future research should explicitly identify the justification for the interventions. Greater use of explicit theory to understand barriers, design interventions, and explore mediating pathways and moderators is needed to advance the science of implementation research.

Abstract Background Biomedical research constantly produces new findings but these are not routinely translated into health care practice. One way to address this problem is to develop effective interventions to translate research findings into practice. Currently a range of empirical interventions are available and systematic reviews of these have demonstrated that there is no single best intervention. This evidence base is difficult to use in routine settings because it cannot identify which intervention is most likely to be effective (or cost effective) in a particular situation. We need to establish a scientific rationale for interventions. As clinical practice is a form of human behaviour, theories of human behaviour that have proved useful in other similar settings may provide a basis for developing a scientific rationale for the choice of interventions to translate research findings into clinical practice. The objectives of the study are: to amplify and populate scientifically validated theories of behaviour with evidence from the experience of health professionals; to use this as a basis for developing predictive questionnaires using replicable methods; to identify which elements of the questionnaire (i.e., which theoretical constructs) predict clinical practice and distinguish between evidence compliant and non-compliant practice; and on the basis of these results, to identify variables (based on theoretical constructs) that might be prime targets for behaviour change interventions. Methods We will develop postal questionnaires measuring two motivational, three action and one stage theory to explore five behaviours with 800 general medical and 600 general dental practitioners. We will collect data on performance for each of the behaviours. The relationships between predictor variables (theoretical constructs) and outcome measures (data on performance) in each survey will be assessed using multiple regression analysis and structural equation modelling. In the final phase of the project, the findings from all surveys will be analysed simultaneously adopting a random effects approach to investigate whether the relationships between predictor variables and outcome measures are modified by behaviour, professional group or geographical location.

The role of expectations based on the Monday-blues stereotype was explored in self-reports of mood throughout the week. Participants (N = 66) were allocated to 3 matched groups. Expectations were manipulated in 2 experimental groups: 1 in support of Monday blues and 1 against them. All participants completed the Positive and Negative Affect Schedule (PANAS) daily for 2 weeks, and ranked the days of the week in terms of mood after completion. While there were no effects on negative affect, the pro-blues group reported lower positive affect on Monday. All 3 groups recalled Monday as the worst day in terms of mood. This suggests that expectations have subtle effects on the experience of Monday blues, and highlights the discrepancies between prospective and retrospective self-reports.

Background: The quality of the decisions reached by data monitoring committees (DMCs) is crucial. The aim of this paper is to identify factors that may make errors more or less likely in small, task-oriented, decision-making expert groups and to consider the implications of these factors for data monitoring committees. Methods: A systematic overview was carried out of reviews of empirical studies of small group processes and decision errors in small, task-oriented decision-making groups in laboratory or real-world settings, published between 1950 and 2002 (n = 57 included reviews). Results: These reviews suggest that a number of factors may increase the likelihood that small groups will make poor and potentially erroneous decisions. The most important of these, in terms of empirical support, are: biased or overly directive leadership, expression of a limited range of opinions during group discussion, poor procedures for identifying or appraising the available information, and presentation of the available information in a way that is likely to result in biased perception of it. Conclusions: The main implications for DMCs relate to membership, the role of the chairperson, the information provided for DMCs and training for DMC members. Selection methods that encourage a degree of diversity within the DMC are recommended. Chairs of DMCs should be experienced members, who have the skills to facilitate a discussion, can manage conflict effectively and can be impartial. Adherence to a prespecified analysis plan is recommended to reduce the risk of error associated with strong evidence or excess information. Training in the use of methodical decision-making procedures, education about the factors that influence decision quality and an opportunity to participate in mock DMC discussions may be of benefit for new members. [ABSTRACT FROM AUTHOR]

Discusses the high incidence of venous thrombosis in both medical and surgical management. Factors which predispose to thrombus formation; Types of venous thrombosis; Clinical methods applied in the treating venous thrombosis.

This article presents information related to deep venous thrombosis. It has been known for some time that the incidence of deep thrombosis found at post-mortem is greatly in excess of that diagnosed clinically. Deep venous thrombosis may lead to pulmonary embolism resulting sometimes in death or in chronic pulmonary hypertension. Locally, the thrombosis may destroy the effect of the muscle-venous pump in the legs. Thrombotic occlusion of major veins in the leg, even if followed by recanalization or adequate collateral circulation, frequently leads to chronic dependent oedema.

This article presents information on lipid metabolism disorders. Xanthomatous skin lesions usually indicate abnormal lipid metabolism. However, exceptions to this are 50% of patients with xanthelasma, patients with reticulo-endothelial disorders and diffuse plane xanthomata. It is now possible to classify the majority of lipid disorders on the basis of alterations in the proteins concerned with their transport. Biochemically, six types of hyperliproteinaemia can be identified. Currently, the diagnosis is best determined by fasting serum cholesterol and triglyceride levels with electrophoresis of the lipoproteins. Classification helps in the selection of specific therapy.

The article focuses on diuretic therapy. After the discovery of the diuretic properties of organic mercurial salts, diuresis was achieved therapeutically with drugs like mercaptomerin or mersalyl, given by injection and sometimes potentiated by ammonium chloride. Diuretics may act in several ways. For example, compounds which increase renal blood flow commonly increase the urinary loss of water and electrolytes. Osmotic diuretics produce their effects largely by an osmotic action within the renal tubule.

Two cases of naevoxanthoendothelioma and von Recklinghausens's syndrome are described and the evidence for an association between these two conditions is discussed. [ABSTRACT FROM AUTHOR]

Four patients who developed diffuse xanthomatous lesions during the course of chronic dertnatoses are described. It is suggested that the association is more than coincidental and is related to the underlying disturbance of the reticulo-endothelial system. [ABSTRACT FROM AUTHOR]

Discusses the aspects of industrial medicine in the association between medical hazards and exposure to vinyl chloride monomer. Occurrence of a long latent interval between initial exposure to a toxic substance; Appearance of clinical evidence of damage; Role of animal experimental work in alerting physicians to the potential toxic effects of chemical substances.