Reduction of emergency department returns after discharge from hospital: Machine learning model to predict emergency department returns 30 days post hospital discharge for medical patients

Dissertation presented as the partial requirement for obtaining a Master's degree in Data Science and Advanced Analytics, specialization in Business AnalyticsPost-hospital discharge returns to emergency departments are associated with reducing the efficiency of the emergency department (ED) utilisation and the quality of healthcare. These returns are often related to the nature of the disease and/or inadequate care. This thesis aims to develop a machine-learning model that predicts ED returns within 30 days of inpatient discharge from Portuguese public hospitals. Different binary classification models were trained and evaluated with a particular focus on sensitivity (predictive power of the critical class of returning patients). The selected model was the Extreme gradient boost Classifier, which showed the best performance on recall and the other considered performance metrics. A cohort of 93 449 medical hospitalisations of adult patients discharged between January 1st, 2018, and December 31st, 2019, was assembled with diagnoses details to be used in this study. According to the problem's requirement, the recall was the performance metric to be maximised. Therefore, Performance optimisation methods were considered, and the final model resulted in a recall of 84.38%, precision of 84.35%, F1 score of 84.36% and accuracy of 84.10%. Future deployment and integration of this ED return predictive analytics into the inpatient care workflow may allow identifying patients that require targeted care interventions that reduce overall healthcare expense and improve health outcomes

When every S-flat module is (flat) projective

Let R be a commutative ring with identity and S a multiplicative subset of R. The aim of this paper is to study the class of commutative rings in which every S-flat module is flat (resp., projective). An R-module M is said to be S-flat if the localization of M at S, M_S, is a flat R_S-module. Commutative rings R for which all S-flat R-modules are flat are characterized by the fact that R/Rs is a von Neumann regular ring for every s in S. While, commutative rings R for which all S-flat R-modules are projective are characterized by the following two conditions: R is perfect and the Jacobson radical J(R) of R is S-divisible. Rings satisfying these conditions are called S-perfect. Moreover, we give some examples to distinguish perfect rings, S-perfect rings, and semisimple rings. We also investigate the transfer results of the "S-perfectness" for various ring constructions, which allows the construction of more interesting examples

Identification de cristaux dans un phoswich par la méthode de mesure de temps au dessus d'un seuil (ToT) pour le scanner LabPET II

La performance d’un scanner TEP se mesure par sa sensibilité, son contraste et sa résolution spatiale. Cette dernière doit être idéalement uniforme dans tout le champ de vue utile (CDV) du scanner. Cependant, le problème de parallaxe dû à l’éloignement de la source du centre de CDV, entraîne une dégradation de la résolution spatiale radiale. Ce problème est très présent dans les scanners avec une grande densité de détecteurs et de petit diamètre notamment dans le LabPET II, le scanner en cours de développement à l’Université de Sherbrooke par le Groupe de recherche en appareillage médicale de Sherbrooke (GRAMS) et le Centre d’imagerie moléculaire de Sherbrooke (CIMS), avec [tilde]37 000 détecteurs pour un CDV de 16 cm de diamètre et 12 cm de longueur axiale. Chaque détecteur a une surface de 1,2[indice supérieur *] 1,2 mm[indice supérieur 2] et une longueur supérieure à 10 mm. La mesure de profondeur d’interaction (PDI) demeure très utile pour résoudre le problème de parallaxe. La PDI peut être réalisée par l’assemblage de deux cristaux en phoswich, tout en gardant la même longueur totale pour assurer une bonne efficacité de détection, et puis, le cristal dans lequel une interaction est faite sera déterminé à l’aide d’algorithme d’identification de cristaux. Pour le traitement des signaux issus des modules de détection, un ASIC de 64 canaux a été développé. L’ASIC utilise une nouvelle technique de mesure de temps à doubles seuils inspirée de la technique de mesure de temps au-dessus d’un seuil (ToT). Cette technique repose sur l’utilisation de deux discriminateurs à seuil afin de déterminer le temps d’arrivée du photon d’annihilation et son énergie. Le temps d’arrivée est estimé par le moment de discrimination du signal avec le premier discriminateur. Tandis que l’énergie du signal est calculée par la différence des moments de discrimination du signal avec le premier et le deuxième discriminateur. Cette différence de temps est non linéaire en fonction de l’énergie. Donc une correction d’énergie est faite pour déterminer le spectre d’énergie. Les seuils des discriminateurs sont méticuleusement choisis afin de minimiser l’erreur sur les temps de croisement. Cette méthode de ToT à doubles seuils est une technique innovatrice pour identifier les cristaux qui ont scintillés [i.e. scintillé] dans un scanner TEP. Avec une erreur inférieure à 5%, cette technique discrimine entre un LGS045ns et un LYSO40ns. Malgré le taux d’erreur élevé comparé à d’autres méthodes d’identification, cette technique possède l’avantage d’être facilement intégrable dans l’ASIC du LabPET II

La experiencia encarnada como nuevo horizonte epistemológico y metodológico en la investigación en comunicación audiovisual. Hacia una concepción de la obra audiovisual como dispositivo encarnado

Avanzamos una propuesta epistemológica y metodológica alternativa para la investigación en comunicación que explora dimensiones materiales, procesuales, relacionales, maquínicas, sensoriales y performativas de la obra audiovisual. A través de un ejercicio cartográfico de mapeo de teorías y aproximaciones al fenómeno audiovisual históricamente disidentes, nos alejamos de la concepción textual de la obra adoptando un enfoque procesual que se interesa por la experiencia audiovisual como vivencia existencialmente encarnada y por la obra como dispositivo capaz de generar formas de sentido más allá de los entramados narrativos y los procesos significantes

Farina milling: development of a flow sheet and a speck counting method

Call number: LD2668 .T4 GRSC 1988 E43Master of ScienceGrain Science and Industr

Solar Radiation and Daylighting Assessment Using the Sky-view Factor (SVF) Analysis as Method to Evaluate Urban Planning Densification Policies Impacts

Abstract This study identifies and proposes simple methods to assess solar radiation, daylighting availability and Sky-View Factor (SVF) modification, in complex urban environment. Numerical methods and 3D simulation software are combined with photo processing methods using digital cameras with special mirrors to project the hemispherical environment onto a circular image. This methodology has been applied to a real case study in Switzerland that is undergoing a very fast urban densification process, where urban planning strategies will determine significantly the possibility to relish solar irradiation in buildings. This paper analyzed the particularities of different urban scenarios considering the effects of urban densification planning strategies on existing buildings, in particular historical protected buildings

Zn speciation in the organic horizon of a contaminated soil by micro X-ray fluorescence, micro and powder EXAFS spectroscopy and isotopic dilution.

Soils which have been acutely contaminated by heavy-metals show distinct characteristics, such as colonization by metal-tolerant plant species and topsoil enrichment in weakly degraded plant debris because biodegradation processes are strongly inhibited by contamination. Such an organic topsoil, located downwind of an active zinc smelter and extremely rich in Zn (~ 2%, dry weight), was investigated by X-ray diffraction (XRD), synchrotron-based X-ray microfluorescence (μSXRF), and powder and micro extended X-ray absorption fine structure (EXAFS) spectroscopy for Zn speciation, and by isotopic dilution for Zn lability. EXAFS spectra recorded on size fractions and on selected spots of thin sections were analyzed by principal component analysis (PCA) and linear combination fits (LCFs). Although Zn primary minerals (franklinite, sphalerite and willemite) are still present (~ 15% of total Zn) in the bulk soil, Zn was found to be predominantly speciated as Zn-organic matter complexes (~ 45%), outer-sphere complexes (~ 20%), Zn-sorbed phosphate (~ 10%) and Znsorbed iron oxyhydroxides (~ 10%). The bioaccumulated Zn fraction is likely complexed to soil organic matter after the plants' death. The proportion of labile Zn ranges from 54 to 92%, depending on the soil fraction, in agreement with the high proportion of organically-bound Zn. Despite its marked lability, Zn seems to be retained in the topsoil thanks to the huge content of organic matter, which confers to this horizon a high sorption capacity. The speciation of Zn in this organic soil horizon is compared with that found in other types of soils

High flow nasal cannula therapy versus continuous positive airway pressure and nasal positive pressure ventilation in infants with severe bronchiolitis: a randomized controlled trial

Introduction: non-invasive ventilation is widely used in the respiratory management of severe bronchiolitis. Methods: a randomized controlled trial was carried out in a tertiary pediatric university hospital´s PICU over 3 years to compare between continuous positive airway pressure/nasal positive pressure ventilation (CPAP/NPPV) and high flow nasal cannula (HFNC) devices for severe bronchiolitis. The trial was recorded in the national library of medicine registry (NCT04650230). Patients aged from 7 days to 6 months, admitted for severe bronchiolitis were enrolled. Eligible patients were randomly chosen to receive either HFNC or CPAP/NPPV. If HFNC failed, the switch to CPAP/NPPV was allowed. Mechanical ventilation was the last resort in case of CPAP/NPPV device failure. The primary outcome was the success of the treatment defined by no need of care escalation. The secondary outcomes were failure predictors, intubation rate, stay length, serious adverse events, and mortality. Results: a total of 268 patients were enrolled. The data of 255 participants were analyzed. The mean age was 51.13 ± 34.43 days. Participants were randomized into two groups; HFNC group (n=130) and CPAP/NPPV group (n=125). The success of the treatment was significantly higher in the CPAP/NPPV group (70.4% [61.6%- 78.2%) comparing to HFNC group (50.7% [41.9%- 59.6%])- (p=0.001). For secondary outcomes, lower baseline pH was the only significant failure predictor in the CPAP/NPPV group (p=0.035). There were no differences in intubation rate or serious adverse events between the groups. Conclusion: high flow nasal cannula was safe and efficient, but CPAP/ NPPV was better in preventing treatment failure. The switch to CPAP/NPPV if HFNC failed, avoided intubation in 54% of the cases