Cross-participant and cross-task classification of cognitive load based on eye tracking

Cognitive load refers to the total amount of working memory resources a person is currently using. Successfully detecting the cognitive load a person is experiencing is the first important step towards applications that adapt to a user’s current load. Provided that cognitive load is estimated correctly, a system can enhance a user’s experience or increase its own efficiency by adapting to this detected load. Using digital learning environments as an example to illustrate this idea, a learning environment could tune the difficulty of presented exercises or learning material to match the learner’s current load to not underwhelm them, but also to prevent overload and frustration. Physiological sensors have great promise when cognitive load estimation is concerned as many physiological signals show distinctive signs of cognitive load. Eye tracking is an especially promising candidate as it does not require physical contact between sensor and user and is therefore very subtle. A major problem is the lack of general classifiers for cognitive load as classifiers are usually specific to a single person and do not generalize well. For adaptive interfaces based on a user’s cognitive load to be viable, a classifier that is accurate and performs well independently of user and specific task would be needed. In the current doctoral thesis, I present four studies that successively build upon each other and build up towards an eye-tracking based classifier for cognitive load that is 1) accurate, 2) robust, 3) can generalize, and 4) can operate in real-time. Each of the presented studies advances our approach’s capability to generalize one step further. Along the way, different eye-tracking features are explored and evaluated for their suitability as predictors of cognitive load and the implications for the distinction between cognitive load and perceptual load are discussed. The resulting method demonstrates a degree of generalization that no other approach has achieved and combines it with low hardware requirements and high robustness into a method that has great promise for future applications. Overall, the results presented in this thesis may serve as a foundation for the use of eye tracking in adaptive interfaces that react to a user’s cognitive load

Ein Beitrag zur Analyse des Schaltverhaltens unipolarer SiC-Transistoren

Das Reverse Recovery der Body-Diode eines unipolaren Transistors beim Schalten induktiver Lasten zeigt eine typische Ladung. Sie kann durch Analyse verschiedener Experimente mit dem Halbleiter in drei Arten unterteilt werden. SiC-Halbleiter weisen im Vergleich zu Si-Halbleitern eine um eine Größenordnung höhere Sperrschichtkapazität auf, da die Feldstärken im Halbleiter in gleichem Maße größer sind. Hierdurch wird beim Reverse Recovery eine bemerkenswerte Menge an Ladung messbar. Anhand von Messungen und Vergleichen ist dies deutlich zu erkennen. Dies wirkt sich auf das Schaltverhalten

Carbapenemase-producing Enterobacteriaceae: A diagnostic, epidemiological and therapeutic challenge

Resumen La diseminación global de las Enterobacteriaceae productoras de carbapenemasas (EPC) se ha convertido en un problema de salud pública. No todas las EPC son resistentes a los carbapenémicos, por lo que representan un reto diagnóstico y terapéutico. Adicionalmente, como la resistencia a los carbapenémicos puede ser mediada por otras β-lactamasas en combinación con cambios de la permeabilidad de la membrana plasmática, su detección puede ser difícil en laboratorios de microbiología que no cuentan con técnicas de diagnóstico molecular, lo que puede restringir y frecuentemente retrasar el inicio de la terapia antimicrobiana adecuada. La evidencia respecto a las medidas para la contención de las EPC es escasa. Sin embargo, existen recomendaciones por parte de la Organización Mundial de la Salud y del European Prevention Center and Disease Control (ECDC). Debido a la ausencia de estudios controlados y aleatorizados, los esquemas terapéuticos se basan en estudios clínicos observacionales. Varios de estos estudios han reportado mejores resultados con la terapia combinada de dos o más agentes activos in vitro, incluyendo a los carbapenémicos, en comparación con la monoterapia. Por otra parte, un nuevo inhibidor de β-lactamasas en combinación con ceftazidime, ha mostrado eficacia clínica contra infecciones por Enterobacteriaceae productoras de KPC y algunas carbapenemasas de tipo OXA.The global spread of carbapenemase-producing Enterobacteriaceae (CPE) has become a public health problem. Not all CPE are resistant to carbapenems creating a diagnostic and therapeutic challenge. Furthermore, as resistance to carbapenems can also be mediated by other β-lactamases combined with defects in membrane permeability, their detection can be difficult by microbiology laboratories that lack molecular tools, which may limit and often delay the correct antibiotic selection. There is only limited evidence regarding infection control measures to contain the spread of CPE. However, recomendations have been published from the World Health Organization (WHO) and the European Prevention Center and Disease Control (ECDC). Because of the lack of randomized control trials, treatment regimens are mostly based on observational clinical studies. Several of those studies have reported that combination therapy with two or more in vitro-active agents including a carbapenem is superior to monotherapy. On the other hand, a new β-lactamase inhibitor in combination with ceftazidime has shown clinical efficacy Against KPC and some OXA-type producing Enterobacteriaceae

Dyssynchronous Left Ventricular Activation is Insufficient for the Breakdown of Wringing Rotation

Cardiac resynchronization therapy is a valuable tool to restore left ventricular function in patients experiencing dyssynchronous ventricular activation. However, the non-responder rate is still as high as 40%. Recent studies suggest that left ventricular torsion or specifically the lack thereof might be a good predictor for the response of cardiac resynchronization therapy. Since left ventricular torsion is governed by the muscle fiber orientation and the heterogeneous electromechanical activation of the myocardium, understanding the relation between these components and the ability to measure them is vital. To analyze if locally altered electromechanical activation in heart failure patients affects left ventricular torsion, we conducted a simulation study on 27 personalized left ventricular models. Electroanatomical maps and late gadolinium enhanced magnetic resonance imaging data informed our in-silico model cohort. The angle of rotation was evaluated in every material point of the model and averaged values were used to classify the rotation as clockwise or counterclockwise in each segment and sector of the left ventricle. 88% of the patient models (n = 24) were classified as a wringing rotation and 12% (n = 3) as a rigid-body-type rotation. Comparison to classification based on in vivo rotational NOGA XP maps showed no correlation. Thus, isolated changes of the electromechanical activation sequence in the left ventricle are not sufficient to reproduce the rotation pattern changes observed in vivo and suggest that further patho-mechanisms are involved

Microbiological and clinical aspects of raoultella spp.

The genus Raoultella was established in 2001. Species of Raoultella and Klebsiella share many ecological, biochemical, clinical, and microbiological features. Given the shortcomings of available technology for species identification in the clinical microbiology laboratory, are practically indistinguishable. Since the late 2000s there has been an increase in case reports of human Raoultella infections. Therefore, several authors are postulating that Raoultella spp. are rare and/or emerging pathogens. Conclusions: Raoultella spp. are very similar to Klebsiella spp. The epidemiology and the clinical relevance of the human Raoultella spp. infections is uncertain and further studies are required. The previous difficulties in the identification of Raoultella spp. and the introduction of more precise identification techniques may explain the recent increase in the number of case reports. Raoultella spp. might be rather underdiagnosed than rare or emerging pathogens. © Copyright © 2021 Appel, Quijano-Martínez, De La Cadena, Mojica and Villegas

Evaluation of Allplex™ Entero-DR assay for detection of antimicrobial resistance determinants from bacterial cultures

Objective To evaluate the sensitivity and specificity of the Allplex™ Entero-DR, a quantitative PCR-based method, for the detection of β-lactamase-encoding genes and vancomycin-resistance determinants in 156 previously characterized Gram-negative bacilli and Enterococcus spp. from bacterial cultures. Result The method had 100% sensitivity and between 92 and 100% of specificity for identifying blaKPC, blaVIM, blaIMP, blaNDM, blaOXA-48-like, blaCTX-M and vanA. In nine isolates, unspecific amplifications were detected. The Ct of these false positives was above 33. The Ct of the correctly identified bla and van genes did not surpass 28 and 30, respectively. None of the clinical isolates included as negative controls yielded any amplification. Therefore, the Allplex™ Entero-DR assay is a highly accurate test for the detection of important antibiotic resistance determinants. With this assay, reliable results can be obtained within 3 h. However, according to our data, samples with Ct values greater than 33 should be considered with caution