On the energy scale involved in the metal to insulator transition of quadruple perovskite EuCu3Fe4O12: infrared spectroscopy and ab-initio calculations.

Optical measurements were carried out by infrared spectroscopy on AA'3B4O12 A-site ordered quadruple perovskite EuCu3Fe4O12 (microscopic sample) as function of temperature. At 240 K (=TMI), EuCu3Fe4O12 undergoes a very abrupt metal to insulator transition, a paramagnetic to antiferromagnetic transition and an isostructural transformation with an abrupt large volume expansion. Above TMI, optical conductivity reveals a bad metal behavior and below TMI, an insulating phase with an optical gap of 125 meV is observed. As temperature is decreased, a large and abrupt spectral weight transfer toward an energy scale larger than 1 eV is detected. Concurrently, electronic structure calculations for both high and low temperature phases were compared to the optical conductivity results giving a precise pattern of the transition. Density of states and computed optical conductivity analysis identified Cu3dxy, Fe3d and O2p orbitals as principal actors of the spectral weight transfer. The present work constitutes a first step to shed light on EuCu3Fe4O12 electronic properties with optical measurements and ab-initio calculations.

Evaluation of three brands of tympanic thermometer.

Infrared tympanic thermometers (ITT) have many documented benefits, including speed, ease of use, and noninvasiveness, to support their use in emergency departments (ED) and intensive care units (ICU). However, concerns have been raised about the accuracy of temperatures reported by ITT. This study was conducted to evaluate the accuracy of 3 brands of ITT, compared to rectal and pulmonary artery thermometers, in ED and ICU settings. Results indicated adequate specificity for all 3 ITT in ED (range = 0.9242 to 1.0000) and ICU (range = 0.9737 to 1.0000), but unacceptable sensitivity in ED (range = 0.5455 to 0.8000) and ICU (range = 0.0000). Further analyses indicated highly variable ITT-reported temperatures. In ED, ITT temperatures were, on average, 0.3684 degree C lower, and could be expected to vary by more than 2 degrees C from the actual temperature as reported by rectal thermometer. In ICU, the average reported temperature was similar to the actual pulmonary artery temperature (0.0259 degree C lower), but again could vary by more than 2 degrees C. Recommendations for nursing and education are discussed.

Precision, accuracy, and reliability of hemoglobin assessment with use of capillary blood.

BACKGROUND: Previous research has suggested that there may be significant within-subject variability, both site-to-site and over time, in hemoglobin concentrations in capillary blood. OBJECTIVE: This study examined the reliability of the portable hemoglobinometer (PHM) system with use of capillary blood and the implications of errors of the magnitude found for the classification of anemia status in individuals and population groups. The precision and accuracy of the method with use of venous blood were also tested. DESIGN: Three empirical data sets were used to measure reliability, precision, and accuracy of the PHM system [2 from Honduras (n = 87 and 141); 1 from Bangladesh (n = 73)]. Simulation data were used to assess the implications of errors for screening individuals for anemia and to estimate anemia prevalence. RESULTS: High within-subject variability (unreliability) was identified when capillary blood from the left hand was compared with that from the right hand (CV: 6.3%) and when measurements were taken on 4 consecutive days (CV: 7.0%). Reliability was only 69% and 50%, respectively. Precision and accuracy, however, were very high (concordance coefficients of 0.99 and 0.98 and CV < 1%). CONCLUSIONS: The simulation data showed that errors of the magnitude found due to unreliability can lead to misclassification of anemia status in individuals and small biases in anemia prevalence estimates. We recommend replicate sampling to reduce the influence of unreliability in the use of the PHM system with capillary blood.