277 research outputs found
Extrinsic Parameter Calibration for Line Scanning Cameras on Ground Vehicles with Navigation Systems Using a Calibration Pattern
Line scanning cameras, which capture only a single line of pixels, have been
increasingly used in ground based mobile or robotic platforms. In applications
where it is advantageous to directly georeference the camera data to world
coordinates, an accurate estimate of the camera's 6D pose is required. This
paper focuses on the common case where a mobile platform is equipped with a
rigidly mounted line scanning camera, whose pose is unknown, and a navigation
system providing vehicle body pose estimates. We propose a novel method that
estimates the camera's pose relative to the navigation system. The approach
involves imaging and manually labelling a calibration pattern with distinctly
identifiable points, triangulating these points from camera and navigation
system data and reprojecting them in order to compute a likelihood, which is
maximised to estimate the 6D camera pose. Additionally, a Markov Chain Monte
Carlo (MCMC) algorithm is used to estimate the uncertainty of the offset.
Tested on two different platforms, the method was able to estimate the pose to
within 0.06 m / 1.05 and 0.18 m / 2.39. We also propose
several approaches to displaying and interpreting the 6D results in a human
readable way.Comment: Published in MDPI Sensors, 30 October 201
Hyperspectral Imaging from Ground Based Mobile Platforms and Applications in Precision Agriculture
This thesis focuses on the use of line scanning hyperspectral sensors on mobile ground based platforms and applying them to agricultural applications. First this work deals with the geometric and radiometric calibration and correction of acquired hyperspectral data. When operating at low altitudes, changing lighting conditions are common and inevitable, complicating the retrieval of a surface's reflectance, which is solely a function of its physical structure and chemical composition. Therefore, this thesis contributes the evaluation of an approach to compensate for changes in illumination and obtain reflectance that is less labour intensive than traditional empirical methods. Convenient field protocols are produced that only require a representative set of illumination and reflectance spectral samples. In addition, a method for determining a line scanning camera's rigid 6 degree of freedom (DOF) offset and uncertainty with respect to a navigation system is developed, enabling accurate georegistration and sensor fusion. The thesis then applies the data captured from the platform to two different agricultural applications. The first is a self-supervised weed detection framework that allows training of a per-pixel classifier using hyperspectral data without manual labelling. The experiments support the effectiveness of the framework, rivalling classifiers trained on hand labelled training data. Then the thesis demonstrates the mapping of mango maturity using hyperspectral data on an orchard wide scale using efficient image scanning techniques, which is a world first result. A novel classification, regression and mapping pipeline is proposed to generate per tree mango maturity averages. The results confirm that maturity prediction in mango orchards is possible in natural daylight using a hyperspectral camera, despite complex micro-illumination-climates under the canopy
From Modeled Topics to Areas of Law: A Comparative Analysis of Types of Proceedings in the German Federal Constitutional Court
Quantitative approaches are gaining popularity in German legal research. The analysis of large corpora of legal text may be supported by text mining methods. In this study, we employ topic modeling—which aims at retrieving the “topics” of a corpus—to identify words related to certain areas of law present in the case law of the German Federal Constitutional Court (FCC). This information is then evaluated by legal experts and used to show significant content-related differences between the two most frequent types of proceedings before the FCC. Technical and somewhat unstable areas of law, such as tax law, social law, and civil service law, are significantly overrepresented in referrals for judicial review, whereas areas of law characterized by well-developed case law and judicial doctrine appear substantially more often in constitutional complaints. This insight may come as a surprise due to the fact that the Court’s material scope of review is identical in both types of proceedings. Our considerations do not, however, seem to apply to private law. Though we recognize the methodological and epistemological concerns regarding the heuristic nature of topic modeling, this study exemplifies its productive use in complementing, rather than replacing, more traditional techniques of analysis in legal studies
Probabilistic analysis of COVID-19 patients' individual length of stay in Swiss intensive care units
RATIONALE
The COVID-19 pandemic induces considerable strain on intensive care unit resources.
OBJECTIVES
We aim to provide early predictions of individual patients' intensive care unit length of stay, which might improve resource allocation and patient care during the on-going pandemic.
METHODS
We developed a new semiparametric distributional index model depending on covariates which are available within 24h after intensive care unit admission. The model was trained on a large cohort of acute respiratory distress syndrome patients out of the Minimal Dataset of the Swiss Society of Intensive Care Medicine. Then, we predict individual length of stay of patients in the RISC-19-ICU registry.
MEASUREMENTS
The RISC-19-ICU Investigators for Switzerland collected data of 557 critically ill patients with COVID-19.
MAIN RESULTS
The model gives probabilistically and marginally calibrated predictions which are more informative than the empirical length of stay distribution of the training data. However, marginal calibration was worse after approximately 20 days in the whole cohort and in different subgroups. Long staying COVID-19 patients have shorter length of stay than regular acute respiratory distress syndrome patients. We found differences in LoS with respect to age categories and gender but not in regions of Switzerland with different stress of intensive care unit resources.
CONCLUSION
A new probabilistic model permits calibrated and informative probabilistic prediction of LoS of individual patients with COVID-19. Long staying patients could be discovered early. The model may be the basis to simulate stochastic models for bed occupation in intensive care units under different casemix scenarios
Helicopter inter-hospital transfer for patients undergoing extracorporeal membrane oxygenation: a retrospective 12-year analysis of a service system.
BACKGROUND
Patients undergoing extracorporeal membrane oxygenation (ECMO) are critically ill and show high mortality. Inter-hospital transfer of these patients has to be safe, with high survival rates during transport without potentially serious and life-threatening adverse events. The Swiss Air-Rescue provides 24-h/7-days per week inter-hospital helicopter transfers that include on-site ECMO cannulation if needed. This retrospective observational study describes adverse events of patients on ECMO transported by helicopter, and their associated survival.
METHODS
All patients on ECMO with inter-hospital transfer by helicopter from start of service in February 2009 until May 2021 were included. Patients not transported by helicopter or with missing medical records were excluded. Patient demographics (age, sex) and medical history (type of and reason for ECMO), mission details (flight distance, times, primary or secondary transport), adverse events during the inter-hospital transfer, and survival of transferred patients were recorded. The primary endpoint was patient survival during transfer. Secondary endpoints were adverse events during transfer and 28-day survival.
RESULTS
We screened 214 ECMO-related missions and included 191 in this analysis. Median age was 54.6 [IQR 46.1-62.0] years, 70.7% were male, and most patients had veno-arterial ECMO (56.5%). The main reasons for ECMO were pulmonary (46.1%) or cardiac (44.0%) failure. Most were daytime (69.8%) and primary missions (n = 100), median total mission time was 182.0 [143.0-254.0] min, and median transfer distance was 52.7 [33.2-71.1] km. All patients survived the transfer. Forty-four adverse events were recorded during 37 missions (19.4%), where 31 (70.5%) were medical and none resulted in patient harm. Adverse events occurred more frequently during night-time missions (59.9%, p = 0.047). Data for 28-day survival were available for 157 patients, of which 86 (54.8%) were alive.
CONCLUSION
All patients under ECMO survived the helicopter transport. Adverse events were observed for about 20% of the flight missions, with a tendency during the night-time flights, none harmed the patients. Inter-hospital transfer for patients undergoing ECMO provided by 24-h/7-d per week helicopter emergency medical service teams can be considered as feasible and safe. The majority of the patients (54.8%) were still alive after 28 days
Factores que predisponen la prevalencia de embarazo en adolescentes inscritas en el programa de Atención Materna en la unidad comunitaria especializada de Sensuntepeque período Enero a Diciembre de 2015.
Título: Factores que predisponen la prevalencia de embarazo en adolescentes inscritas en el programa de Atención Materna en la unidad comunitaria especializada de Sensuntepeque período Enero a Diciembre de 2015. Propósito: Generar información veraz y contundente de los factores que predisponen la prevalencia de embarazo en adolescentes, elaborar una mejor guía a las políticas de salud sexual en adolescentes del municipio, orientaciones para mejoras de charlas y cuidados en educación sexual en las adolescentes para SIBASIS Cabañas. Método y estudio: se realizó un método de estudio descriptivo el cual, deduce las circunstancias estudiados con una población de mujeres embarazadas adolescentes entre 10 -19 años, inscritas en el programa de atención materna en UCSFE Sensuntepeque. Resultados: Las adolescentes encuestadas, el 84% eran adolescentes ente las edades de 16-19 años y el 16% entre las edades de 13-15 años de edad. Utilizaron métodos de Planificación Familiar en un 100% tuvieron acceso a ellos ya sea por el MINSAL (91%) o en forma privada por Farmacias (9%). Se observó también que el 88.33% no habían hablado de sexualidad con sus padres o sobre temas sexuales y el 11.67% si habían hablado del tema. Conclusión: La falta de conocimiento de métodos de planificación no incide en los embarazos en adolescentes inscritas en UCSFE Sensuntepeque. Los factores sociales que más influyeron son la edad entre las adolescentes medias y tardías, y que el factor cultural como la religión católica tiene una relación directamente proporcional con la no aceptación de método de planificación. Recomendaciones: al Ministerio de Salud enfatizar al reforzamiento de educación sexual hacia las adolescentes, al Ministerio de Educación realizar talleres de educación sexual, charlas de tabúes sexuales para maestros de tercer ciclo y bachillerato. A los padres de familias promover e incentivar a la comunicación continua de educación sexual con sus hijos
The importance of post marketing quality control
BACKGROUND
A previously published study reported on the nonlinear behaviour for airway pressure and tidal volume of the adjustable pressure-limiting (APL) valve of the Aisys CS2 anaesthesia machine (GE Healthcare, Madison, Wisconsin, USA) during manual bag ventilation. In co-operation with the manufacturer, an adapted APL valve was developed.
OBJECTIVE
To test and characterise the performance of an adapted APL valve and assess its clinical usability.
DESIGN
Two-stage study, consisting of an in-vitro testing of an adapted APL valve in a baby and adolescent lung model, followed by a clinical experience survey of anaesthesia personnel after the official implementation of the new APL valve into clinical routine.
SETTING
Anaesthesia Department at the University Children's Hospital Zurich.
MAIN OUTCOME MEASURES
Airway pressures and inspiratory tidal volumes during opening and closure of the APL valve at different settings. Likert scale assessment of performance expectance, effort expectance, behavioural intention and safety of the APL valve during clinical use.
RESULTS
In contrast to the original APL valve of the GE Aisys CS2, the adapted APL valve showed a nearly linear increase in airway pressures as well as in the tidal volumes measured. Most importantly, the measured pressures never exceeded the set pressures. Based on the experimental findings, all original APL valves of the GE Aisys CS2 were replaced by the adapted APL valve. Two months later, an anonymised and standardised questionnaire was handed out to all employees working with the adapted APL valve. Analysis of the questionnaire indicated that the adapted APL valve is easier and more precise to handle in the daily routine than the original one.
CONCLUSION
The newly adapted APL valve for the GE Aisys CS2 has considerably improved its linearity at lower pressures and supports our institution's bag mask ventilation practices
Genetic characterization and emergence of the Metallo-β-Lactamase GIM-1 in Pseudomonas spp. and Enterobacteriaceae during a long-term outbreak
Since the first isolation in 2002, the metallo-β-lactamase GIM-1 has not been detected outside Germany. The data presented here, for 50 clinical blaGIM-1-positive isolates, including Pseudomonas spp. and Enterobacteriaceae (Enterobacter cloacae, Klebsiella oxytoca, Serratia marcescens, Escherichia coli, and Citrobacter freundii), collected between 2007 and 2012 at the original site in an ongoing outbreak, demonstrate a diverse genetic background and dissemination of the gene conferring resistance to enteric bacteria
German Multicenter Study Analyzing Antimicrobial Activity of Ceftazidime-Avibactam of Clinical Meropenem-Resistant Pseudomonas aeruginosa Isolates Using a Commercially Available Broth Microdilution Assay
Multidrug resistance is an emerging healthcare issue, especially concerning Pseudomonas aeruginosa. In this multicenter study, P. aeruginosa isolates with resistance against meropenem detected by
routine methods were collected and tested for carbapenemase production and susceptibility against
ceftazidime-avibactam. Meropenem-resistant isolates of P. aeruginosa from various clinical materials
were collected at 11 tertiary care hospitals in Germany from 2017–2019. Minimum inhibitory concentrations (MICs) were determined via microdilution plates (MICRONAUT-S) of ceftazidime-avibactam
and meropenem at each center. Detection of the presence of carbapenemases was performed by
PCR or immunochromatography. For meropenem-resistant isolates (n = 448), the MIC range of
ceftazidime-avibactam was 0.25–128 mg/L, MIC90 was 128 mg/L and MIC50 was 16 mg/L. According to EUCAST clinical breakpoints, 213 of all meropenem-resistant P. aeruginosa isolates were
categorized as susceptible (47.5%) to ceftazidime-avibactam. Metallo-β-lactamases (MBL) could be
detected in 122 isolates (27.3%). The MIC range of ceftazidime-avibactam in MBL-positive isolates was 4–128 mg/L, MIC90 was >128 mg/L and MIC50 was 32 mg/L. There was strong variation in
the prevalence of MBL-positive isolates among centers. Our in vitro results support ceftazidimeavibactam as a treatment option against infections caused by meropenem-resistant, MBL-negative
P. aeruginosa
The First Collective Examination of Immunosuppressive Practices Among American Intestinal Transplant Centers
BACKGROUND: Unlike other solid organs, no standardized treatment algorithms exist for intestinal transplantation (ITx). We established a consortium of American ITx centers to evaluate current practices.
METHODS: All American centers performing ITx during the past 3 y were invited to participate. As a consortium, we generated questions to evaluate and collect data from each institution. The data were compiled and analyzed.
RESULTS: Ten centers participated, performing 211 ITx during the past 3 y (range, 3-46; mean 21.1). Induction regimens varied widely. Thymoglobulin was the most common, used in the plurality of patients (85/211; 40.3%), but there was no consensus regimen. Similarly, regimens for the treatment of acute cellular rejection, antibody-mediated rejection, and graft-versus-host disease varied significantly between centers. We also evaluated differences in maintenance immunosuppression protocols, desensitization regimens, mammalian target of rapamycin use, antimetabolite use, and posttransplantation surveillance practices. Maintenance tacrolimus levels, stoma presence, and scoping frequency were not associated with differences in rejection events. Definitive association between treatments and outcomes, including graft and patient survival, was not the intention of this initial collaboration and is prevented by the lack of patient-level data and the presence of confounders. However, we identified trends regarding rejection episodes after various induction strategies that require further investigation in our subsequent collaborations.
CONCLUSIONS: This initial collaboration reveals the extreme heterogeneity of practices among American ITx centers. Future collaboration will explore patient-level data, stratified by age and transplant type (isolated intestine versus multivisceral), to explore the association between treatment regimens and outcomes
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