Portable blood gas and electrolyte analyzer evaluated in a multiinstitutional study

A recently introduced blood gas/electrolyte analyzer (SenDx 100((R)), renamed ABL70) intended for point-of-care, near-patient, or stat laboratory use was evaluated simultaneously in four different institutions and compared with three different laboratory bench analyzers with respect to imprecision, inaccuracy (assessed by tonometry), and patient-sample analyses. The analyzer is equipped with a sensor cassette and a reagent cartridge for 50, 100, or 200 analyses and 100 or more traditional quality-control measurements. One analysis requires 170 microL of whole blood and takes <90 s. Statistically, the instrument performed somewhat better (lower CVs) for PO2 and potassium and somewhat worse for pH, PCO2, and ionized calcium than the respective comparison analyzers. However, the overall performance (in terms of CV and accuracy) was satisfactory in terms of clinical (e.g., CLIA '88) goals in all institutions. The mean difference and the CV of that difference in some 400 patient-sample comparisons were as follows: 0.010 (+/- 0.002%) for pH, -0.65 mmHg (+/- 4%) for PCO2, -0.49 mmHg (+/- 6%) for Po2, 0.44 mmol/L (+/- 1.2%) for sodium, -0.013 mmol/L (+/- 2.9%) for potassium, -0.016 mmol/L (+/- 2.6%) for ionized calcium, and -0.016 L/L (+/- 7. 1%) for the hematocrit. Its acceptable analytical performance and ease of operation make the SenDx 100 suitable for the analysis of blood gases and electrolytes

Verified global optimization for estimating the parameters of nonlinear models

Nonlinear parameter estimation is usually achieved via the minimization of some possibly non-convex cost function. Interval analysis allows one to derive algorithms for the guaranteed characterization of the set of all global minimizers of such a cost function when an explicit expression for the output of the model is available or when this output is obtained via the numerical solution of a set of ordinary differential equations. However, cost functions involved in parameter estimation are usually challenging for interval techniques, if only because of multi-occurrences of the parameters in the formal expression of the cost. This paper addresses parameter estimation via the verified global optimization of quadratic cost functions. It introduces tools for the minimization of generic cost functions. When an explicit expression of the output of the parametric model is available, significant improvements may be obtained by a new box exclusion test and by careful manipulations of the quadratic cost function. When the model is described by ODEs, some of the techniques available in the previous case may still be employed, provided that sensitivity functions of the model output with respect to the parameters are available

Comparison of three nudge interventions (priming, default option, and perceived variety) to promote vegetable consumption in a self-service buffet setting.

BACKGROUND: Dietary choices in out-of-home eating are key for individual as well as for public health. These dietary choices are caused by a wide array of determinants, one of which is automatic decision-making. Nudging is attracting considerable interest due to its understanding and application of heuristic biases among consumers. The aim of this study is to test and compare three nudges in promoting vegetable consumption among test persons in a food lab-based experiment. METHODS: The initial sample consisted of 88 participants recruited in Copenhagen, Denmark. Each study participant was randomly assigned to one of the three experiments: priming, default and perceived variety. The priming arm of the experiment consisted of creating a leafy environment with green plants and an odour of herbs. In the default arm of the experiment, the salad was pre-portioned into a bowl containing 200g of vegetables. The third experiment divided the pre-mixed salad into each of its components, to increase the visual variety of vegetables, yet not providing an actual increase in items. Each individual was partaking twice thus serving as her/his own control, randomly assigned to start with control or experimental setting. RESULTS: The default experiment successfully increased the energy intake from vegetables among the study participants (124 kcal vs. 90 kcal in control, p<0.01). Both the priming condition and perceived variety reduced the total energy intake among the study participants (169 kcal, p<0.01 and 124 kcal, p<0.01, respectively), mainly through a decrease in the meat-based meal component. CONCLUSIONS: Considerable progress has been made with regard to understanding the use of nudging in promoting a healthier meal composition, including increasing vegetable intake. This study suggests that the nature of a nudge-based intervention can have different effects, whether it is increasing intake of healthy components, or limiting intake of unhealthy meal components. This work has demonstrated that consumer behaviour can be influenced without restricting or providing incentives for behaviour change. The present findings have promising application to the foodservice sector