506 research outputs found
The impact of kombi-taxis on public transport
No full textIncludes bibliography.This thesis attempts to quantify the impact of kombi-taxis on the conventional modes of public transport, in particular the bus, in the Cape Town Metropolitan Area. The impact is quantified in terms of the resultant modal shift of commuters from the buses, trains, cars and walking, in favour of the kombi-taxi. The approach adopted involved a study of the kombi-taxi and bus operations and characteristics on the different kombi-taxi routes in the study area. Five representative routes were selected for a detailed study, involving an Observation survey and an Interview survey directed at the bus and kombi-taxi users on these routes. On a further 66 routes, a bus-taxi modal split survey was conducted. The findings of the study show• that the majority of present kombi-taxi users are former bus users. Conservatively, an estimated 30.6% of all the daily bus passenger trips have been lost to the kombi-taxi. The effect on trains has not been insignificant with an estimated 4.4% of all commuter train trips having been converted to kombi-taxi trips
Molecular and imaging biomarkers in Alzheimer’s disease: A focus on recent insights
No full textAlzheimer’s disease (AD) is the most common neurodegenerative disease among the elderly, affecting millions of people worldwide and clinically characterized by a progressive and irreversible cognitive decline. The rapid increase in the incidence of AD highlights the need for an easy, efficient and accurate diagnosis of the disease in its initial stages in order to halt or delay the progression. The currently used diagnostic methods rely on measures of amyloid-β (Aβ), phosphorylated (p-tau) and total tau (t-tau) protein levels in the cerebrospinal fluid (CSF) aided by advanced neuroimaging techniques like positron emission tomography (PET) and magnetic resonance imaging (MRI). However, the invasiveness of these procedures and the high cost restrict their utilization. Hence, biomarkers from biological fluids obtained using non-invasive methods and novel neuroimaging approaches provide an attractive alternative for the early diagnosis of AD. Such biomarkers may also be helpful for better understanding of the molecular mechanisms underlying the disease, allowing differential diagnosis or at least prolonging the pre-symptomatic stage in patients suffering from AD. Herein, we discuss the advantages and limits of the conventional biomarkers as well as recent promising candidates from alternative body fluids and new imaging techniques
A Key Performance Indicator to Analyze Swarm Learning Performances with EHR
No full textSwarm Learning (SL) has been recently proposed for distributed learning, where a group of individual centers perform a synchronized training. Unlike traditional machine learning models that rely on a central server, swarm learning distributes the learning process across multiple nodes. Each node independently processes data and contributes to the overall learning task. This collaboration allows the swarm to benefit from individual nodes' different data. Unlike federated learning, here model parameters are not handled by a central server but are randomly handled across each individual node. The intrinsic attention of swarm learning to data privacy makes it suitable for distributed health care analysis, where a clinical center wants to benefit from all the other ones in the swarm network. However, the benefit for a single center or for the whole network could vary depending on data distribution. In this paper, we want to analyze the performance of the swarm learning in a network with multiple nodes, where different data distribution scenarios are taken into account. This analysis will show the gain of the whole swarm network and a specific (reference) node, focusing on scenarios where this node has a different amount of data with respect to the other nodes. To perform a more analytical analysis, we introduce a new Key Performance Indicator (KPI) to measure such gain. We then applied this method using I CU data extracted from the MIMIC EHR database and discussed the results obtained by analyzing 5 nodes with different data distribution scenarios
Genetic Architecture and Molecular, Imaging and Prodromic Markers in Dementia with Lewy Bodies: State of the Art, Opportunities and Challenges
No full textDementia with Lewy bodies (DLB) is one of the most common causes of dementia and belongs to the group of α-synucleinopathies. Due to its clinical overlap with other neurodegenerative disorders and its high clinical heterogeneity, the clinical differential diagnosis of DLB from other similar disorders is often difficult and it is frequently underdiagnosed. Moreover, its genetic etiology has been studied only recently due to the unavailability of large cohorts with a certain diagnosis and shows genetic heterogeneity with a rare contribution of pathogenic mutations and relatively common risk factors. The rapid increase in the reported cases of DLB highlights the need for an easy, efficient and accurate diagnosis of the disease in its initial stages in order to halt or delay the progression. The currently used diagnostic methods proposed by the International DLB consortium rely on a list of criteria that comprises both clinical observations and the use of biomarkers. Herein, we summarize the up-to-now reported knowledge on the genetic architecture of DLB and discuss the use of prodromal biomarkers as well as recent promising candidates from alternative body fluids and new imaging techniques
Combi-terminal: Studie naar het toepassen van het combi-terminal concept op een moderne marine terminal
No full textDe kaden bij de marine containerterminals in Noord-Westeuropa hebben een lage bezettingsgraad. De investeringen in de kaden leveren daardoor een laag rendement op. Als oplossing voor dit probleem is het combi-terminal concept naar voren gekomen in de voorgaande studie "Innovatief kade-concept". Bij dit concept worden naast containerschepen ook andere zeeschepen aan de kade behandeld welke een ander produkt aanvoeren. Hiermee zijn de bezettingsgraden te verhogen en het rendement van de kade. Het concept is uitgewerkt voor een containerterminal in de Rotterdamse haven welke in 2007 operationeel moet zijn om de doorgroeiende containerstroom op te vangen. Een dergelijke terminal moet voldoen aan de nieuwste eisen van de gebruiker, met name de containerrederijen. De verwachting is dat deze met 8.000 TEU schepen de belangrijkste lijndiensten gaan onderhouden en eisen dat deze niet langer dan 24 uur in een haven mogen verblijven. Vanuit deze eis volgt de belangrijkste eis aan terminals, een ligplaatsproduktie zien te realiseren van 250 containers per uur. Door per ligplaats 5 twee-kat-kranen in te zetten welke geplaatst zijn op een verhoogde achterkraanbaan kan aan deze eis worden voldaan. Het rendement van een kade neemt dan ook toe doordat er 2,5 keer zoveel containers over de kade gaan in vergelijking met de huidige kaden waar 100 containers per uur per ligplaats over de kade gaan. De terminal moet daarnaast wel investeren in een opslagconcept met een hogere in- en uitslagcapaciteit. Binnen het gekozen concept wordt het rendement verder verhoogd door ook chemie- en olieprodukten over te slaan op de kade. Daarnaast is ook een opslag in de kade geïntegreerd waarin chemie- en/of olieprodukten kunnen worden opgeslagen. Hiermee kunnen ook extra inkomsten per meter kade binnenkomen. Op de Maasvlakte is een opslag in de kade het beste te realiseren door het toepassen van een ontlastconstructie. Deze constructie kan in een open bouwput gebouwd worden als er nog geen activiteiten plaatsvinden op het terminalterrein. De kosten van een dergelijke kade kunnen worden opgebracht door investeringen die gedaan moeten worden voor gelijkwaardige voorzieningen. De overlast voor de containerterminal is minimaal doordat de voorzieningen boven de grond beperkt blijven. Alleen een verhoogd platform met daarop laadarmen voor het behandelen van de tankers staat bovengronds per ligplaats opgesteld. Bij de terminal moet wel een aparte ondiepwaterkade worden aangelegd voor de behandeling van de binnenvaart die niet meer aan de zeekade wordt behandeld. De kadecapaciteit die over is wordt ingezet voor de behandeling van olie- en chemietankers. Nader onderzoek naar de bezetting van de kade en de te verwachten wachttijd en is noodzakelijk om de haalbaarheid met zekerheid vast te stellen. Afhankelijk daarvan kunnen ook de eisen worden vastgesteld die aan de containerschepen en de tankers worden gesteld. Als er dan een bezettingsgraad van 60% valt te realiseren is het concept van de combi-terminal haalbaar, ook op een moderne marine containerterminal.Hydraulic EngineeringCivil Engineering and Geoscience
Querying temporal clinical databases with different time Granularities: the GCH-OSQL language
No full textQuerying Clinical Workflows by Temporal Similarity
No full textThe degree of fulfillment of clinical guidelines is considered a key factor when evaluating the quality of a clinical service. Guidelines can be seen as processes describing the sequence of activities to be done. Consequently, workflow formalisms seem to be a valid approach to model the flow of actions in the guideline and their temporal aspects. The application of a guideline to a specific patient (guideline instance) can be modeled by means of a workflow case. The best (worst) application of a guideline, represented as a reference workflow case, can be used to evaluate the quality of the service, by comparing the optimal case with specific patient instances. On the other hand, the correct application of a guideline to a patient involves the fulfillment of the guideline temporal constraints. Thus, the evaluation of the temporal similarity degree between different workflow cases is a key aspect in evaluating health care quality. In this work, we represent a portion of the stroke guideline using a temporal workflow schema and we propose a method to evaluate the temporal similarity between workflow cases. Our proposal, based on temporal constraint networks, consists of a linear combination of functions to differentiate intra-task and inter-task temporal distances
The T4SQL Temporal Query Language
No full textTime characterizes every aspect of our life and its management when storing and querying data is very important. In this paper we propose a new temporal query language, called T4SQL, supporting multiple temporal dimensions of data. Besides the well-known valid and transaction times, it encompasses two additional temporal dimensions, namely, availability and event times. The availability time records when information is known and treated as true by the information system; the event times record the occurrence times of both the event that starts the valid time and the event that ends it. T4SQL is capable to deal with different temporal semantics (atemporal aka non-sequenced, current, sequenced, next) with respect to every temporal dimension. Moreover, T4SQL provides a novel temporal grouping clause and an orthogonal management of temporal properties when defining the selection condition(s) and the schema for the output relation
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