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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Titrating Open Lung PEEP in Acute Lung Injury : A clinical method based on changes in dynamic compliance

Suarez Sipmann, Fernando January 2008 (has links)
The recognition that supportive mechanical ventilation can also damage the lung, the so called ventilation induced lung injury (VILI), has revived the more than 40 year long debate on the optimal level of PEEP to be used. It is established that the prevention of VILI improves patient outcome and that PEEP exerts protective effects by preventing unstable diseased alveoli from collapsing. Therefore, the term “open lung PEEP” (OL-PEEP) has been introduced as the end-expiratory pressure that keeps the lung open after its collapse has been eliminated by an active lung recruitment manoeuvre. The determination of such an optimal level of PEEP under clinical circumstances is difficult and remains to be investigated. The aim of this study was to investigate the usefulness of breath by breath monitoring of dynamic compliance (Cdyn) as a clinical means to identify OL-PEEP at the bedside and to demonstrate the improvement in lung function resulting from its application. In a porcine lung lavage model of acute lung injury PEEP at maximum Cdyn during a decremental PEEP trial after full lung recruitment was related to the onset of lung collapse and OL-PEEP could be found 2 cmH2O above this level Ventilation at OL-PEEP was associated with improved gas exchange, efficiency of ventilation, lung mechanics and less than 5% collapse on CT scans. In addition, dead space, especially its portion related to alveolar gas changed characteristically during recruitment, PEEP titration and collapse thereby helping to identify OL-PEEP. The beneficial effects of OL-PEEP on lung function and mechanics was demonstrated in a porcine model of VILI. OL-PEEP improved lung function and mechanics when compared to lower or higher levels prior to or after lung recruitment. By using electrical impedance tomography it could be shown that PEEPs within the range of 14 to 22 cmH2O resulted in a similar redistribution of both ventilation and perfusion to the dorsal regions of the lung. OL-PEEP resulted in the best regional and global matching of ventilation and perfusion explaining the drastic improvements in gas exchange. Also regional compliance was greatly improved in the lower half of the lung as compared to all other situations. In ARDS patients OL-PEEP could be identified applying the same protocol. The physiological changes described could now be reproduced and maintained during a four hours study ventilation period in real patients at four study centres. In conclusion, the usefulness of dynamic compliance for identifying open lung PEEP during a decremental PEEP trial was demonstrated under experimental and clinical conditions. This PEEP should then be used as an essential part of any lung protective ventilation strategy. The impact of ventilating ARDS patients according to the principles described in these studies on outcome are currently being evaluated in an international randomized controlled trial.
182

Duties to Past Persons : Moral Standing and Posthumous Interests of Old Human Remains

Masterton, Malin January 2010 (has links)
Genetic research has increasing power to analyse old biological remains. Biological traces of well-known historical persons can reveal personal information. The aim of this thesis is to investigate ethical concerns for the dead, within the biological, historical and archaeological sciences. In philosophy there is a long-running discussion on whether or not the dead can be wronged. The good name is proposed as a candidate of a posthumous interest. It is first of all argued that slandering per se can be wrong regardless of posthumous wronging of the dead. Secondly, the concept of change is investigated. It is argued that the property of having a reputation is a relational property. Hence a change in public opinion of a dead person, is also a change in the dead person’s reputation. The third contribution of this thesis is a constructive proposal for how a posthumous identity could be understood using narrative theory. Understanding identity through the life-story opens up the possibility of a gradual loss of identity after death, rather than absolute loss at the moment of death. Fragments of a person‘s narrative identity can persist in other peoples’ narratives, and for some historical persons, their narratives can be found long after their death. Finally, the implications of a remaining narrative identity for the dead are investigated in the area of archaeology and museumology. In the past 30 years, there has been increasing critique about present and past discriminatory handling of old human remains by archaeologists, in museums and in other institutions. Increasing numbers of requests have been made for repatriation or reburial of old human remains. Following an analysis of three current ethical guidelines in handling old human remains, changes to these guidelines are proposed based on a narrative method to a hypothetical claim of reburial.
183

Enhancement of the Mesophilic Anaerobic Co-digestion of Municipal Sewage and Scum

Young, Bradley 23 November 2012 (has links)
Scum is an integral component of solids management in MWWTP and is composed of fats, oils, grease and other entrained floatable materials that are collected during primary clarification. Lab scale BMP tests showed the addition of 14.5 g VS/L of scum exhibited the greatest increase in biogas production of 1.6 times per g VS added compared to the control, while a higher additional scum loading of 33.7 g VS/L reduced the biogas yield to 32% of the control reactor. Lab scale semi-continuous digestion measured the effects of scum loading and temperature of pretreatment in the scum concentrator. At 15 d and 20 d HRTs the greatest observed improvement in biogas was achieved by adding 3% scum by volume and pretreating the scum at 70°C in a scum concentrator with respective improvements of 24% and 16%.
184

Functional Role of Dead-Box P68 RNA Helicase in Gene Expression

Lin, Chunru 31 July 2006 (has links)
How tumor cells migrate and metastasize from primary sites requires four major steps: invasion, intravasation, extravasation and proliferation from micrometastases to malignant tumor. The initiation of tumor cell invasion requires Epithelial-Mesenchymal Transition (EMT), by which tumor cells lose cell-cell interactions and gain the ability of migration. The gene expression profile during the EMT process has been extensively investigated to study the initiation of EMT. In our studies, we indicated that tyrosine phosphorylation of human p68 RNA helicase positively associated with the malignant status of tumor tissue or cells. Studying of this relationship revealed that p68 RNA helicase played a critical role in EMT progression by repression of E-cadherin as an epithelial marker and upregulation of Vimentin as a mesenchymal marker. Insight into the mechanism of how p68 RNA helicase represses E-cadherin expression indicated that p68 RNA helicase initiated EMT by transcriptional upregulation of Snail. Human p68 RNA helicase has been documented as an RNA-dependent ATPase. The protein is an essential factor in the pre-mRNA splicing procedure. Some examples show that p68 RNA helicase functions as a transcriptional coactivator in ATPase dependent or independent manner. Here we indicated that p68 RNA helicase unwound protein complexes to modulate protein-protein interactions by using protein-dependent ATPase activity. The phosphorylated p68 RNA helicase displaced HDAC1 from the chromatin remodeling MBD3:Mi2/NuRD complex at the Snail promoter. Thus, our data demonstrated an example of protein-dependent ATPase which modulates protein-protein interactions within the chromatin remodeling machine.
185

A PC-based data acquisition system for sub-atomic physics measurements

Chabot, Daron 23 July 2008
Modern particle physics measurements are heavily dependent upon automated data acquisition systems (DAQ) to collect and process experiment-generated information. One research group from the University of Saskatchewan utilizes a DAQ known as the Lucid data acquisition and analysis system. This thesis examines the project undertaken to upgrade the hardware and software components of Lucid. To establish the effectiveness of the system upgrades, several performance metrics were obtained including the system's dead time and input/output bandwidth.<p>Hardware upgrades to Lucid consisted of replacing its aging digitization equipment with modern, faster-converting Versa-Module Eurobus (VME) technology and replacing the instrumentation processing platform with common, PC hardware. The new processor platform is coupled to the instrumentation modules via a fiber-optic bridging-device, the sis1100/3100 from Struck Innovative Systems.<p>The software systems of Lucid were also modified to follow suit with the new hardware. Originally constructed to utilize a proprietary real-time operating system, the data acquisition application was ported to run under the freely available Real-Time Executive for Multiprocessor Systems (RTEMS). The device driver software provided with sis1100/3100 interface also had to be ported for use under the RTEMS-based system. <p>Performance measurements of the upgraded DAQ indicate that the dead time has been reduced from being on the order of milliseconds to being on the order of several tens of microseconds. This increased capability means that Lucid's users may acquire significantly more data in a shorter period of time, thereby decreasing both the statistical uncertainties and data collection duration associated with a given experiment.
186

Map Aided Indoor Positioning / Kartstödd Inomhuspositionering

Kihlberg, Johan, Tegelid, Simon January 2012 (has links)
The popularity of wireless sensor networks is constantly increasing, both for use instatic machine to machine environments as well as dynamic environments wherethe sensor nodes are carried by humans. Higher demands are put on real-timetracking algorithms of the sensor nodes, both in terms of accuracy and speed. This thesis addresses the issue of tracking persons wearing small sensor nodeswithin a radio network. Focus lies on fusing sensor data in an efficient way withconsideration to the computationally constrained sensor nodes. Different sensorsare stochastically modelled, evaluated, and fused to form an estimate of the person’sposition. The central approach to solve the problem is to use a dead reckoning methodby detecting steps taken by the wearer combined with an Inertial MeasurementUnit to calculate the heading of the person wearing the sensor node. To decreasethe unavoidable drift which is associated with a dead reckoning algorithm, a mapis successfully fused with the dead reckoning algorithm. The information from themap can to a large extent remove drift. The developed system can successfully track a person wearing a sensor nodein an office environment across multiple floors. This is done with only minorknowledge about the initial conditions for the user. The system can recover fromdivergence situations which increases the long term reliability. / Intresset för trådlösa sensornätverk ökar konstant, såväl för statiska maskintill-maskintillämpningar som för dynamiska miljöer där sensornoderna är burnaav människor. Allt högre krav ställs på positioneringsalgoritmer för sensornätverken,där både hög precision och låg beräkningstid ofta är krav. Denna rapport behandlar problemet med att bestämma positionen av personburnasensornoder. Rapportens fokus är att effektivt kombinera sensordatamed hänsyn till sensornodernas begränsade beräkningskapacitet. Olika sensorermodelleras stokastiskt, utvärderas och kombineras för att forma en skattning avsensornodens position. Den huvudsakliga metoden för att lösa problemet är att dödräkna sensornodbärarenssteg kombinerat med kompass och tröghetssensorer för att skattastegets riktning. En karta över byggnaden används för att reducera den annarsoundvikliga drift som härrör från dödräkning. Informationen från kartan visarsig i stor utsträckning kunna reducera den här driften. Det utvecklade systemet kan följa en person genom en kontorsmiljö somsträcker sig över flera våningsplan. Detta med enbart lite information om personensinitiala position. Systemet kan även återhämta sig från situationer däralgoritmen divergerar vilket ökar systemets pålitlighet på lång sikt.
187

Betydelse av lövinslag, död ved och variation i träddiameter för artrikedomen hos småfåglar / Importance of deciduous trees, dead wood and variation in tree diameter for species richness in birds

Forssén, Annika January 2011 (has links)
Forest management contributes to the changes in forest structure by turning heterogenous forests of varied age into homogenous forests of similar age and thus affect bird species depending on different structures or habitats which are lost during forestry. In this report, a study was made to investigate how the amount of decidious trees, dead wood and variation in tree diameter affect bird diversity. The purpose of this study was to be able to give forest management guidelines to increase bird diversity. This study was conducted by investigating 65 transects in forests of different structure south of Linköping, Sweden. Along the 65 transects, birds were inventoried as well as the vegetation. The trees were measured in 5 circles along each transect. The data from the investigations both on birds and vegetation were analysed by using generalized linear models. The results showed that amount of deadwood and variation in tree diameter had the strongest effects on bird diversity, and to some extent the amount of decidious trees. By applying this knowledge of the positivt effects on birds when increasning the amount of deadwood, decidious trees and variation in tree diameter in the forests, it is possible to create better conditions for maintaining species richness and diversity.
188

Land of the dead : Mer än bara zombies

Nilsson, Tom, Fristedt, Carl January 2012 (has links)
Vår uppsats kommer beröra Zombies på film och fokusera på filmen Land of the Dead. Många människor upplever zombies som inget mer än monster, en fara för karaktärerna att klara sig undan. Vi vill uppmärksamma att all populärkultur i varierande utsträckning gestaltar verklighet, och analysera hur Zombies används för att gestalta aspekter av vårt samhälle.
189

Vehicle Positioning with Map Matching Using Integration of a Dead Reckoning System and GPS / Integration av dödräkning och GPS för fordonspositionering med map matching

Andersson, David, Fjellström, Johan January 2004 (has links)
To make driving easier and safer, modern vehicles are equipped with driver support systems. Some of these systems, for example navigation or curvature warning systems, need the global position of the vehicle. To determine this position, the Global Positioning System (GPS) or a Dead Reckoning (DR) system can be used. However, these systems have often certain drawbacks. For example, DR systems suffer from error growth with time and GPS signal masking can occur. By integrating the DR position and the GPS position, the complementary characteristics of these two systems can be used advantageously. In this thesis, low cost in-vehicle sensors (gyroscope and speedometer) are used to perform DR and the GPS receiver used has a low update frequency. The two systems are integrated with an extended Kalman filter in order to estimate a position. The evaluation of the implemented positioning algorithmshows that the system is able to give an estimated position in the horizontal plane with a relatively high update frequency and with the accuracy of the GPS receiver used. Furthermore, it is shown that the system can handle GPS signal masking for a period of time. In order to increase the performance of a positioning system, map matching can be added. The idea with map matching is to compare the estimated trajectory of a vehicle with roads stored in a map data base, and the best match is chosen as the position of the vehicle. In this thesis, a simple off-line map matching algorithm is implemented and added to the positioning system. The evaluation shows that the algorithm is able to distinguish roads with different direction of travel from each other and handle off-road driving.
190

A PC-based data acquisition system for sub-atomic physics measurements

Chabot, Daron 23 July 2008 (has links)
Modern particle physics measurements are heavily dependent upon automated data acquisition systems (DAQ) to collect and process experiment-generated information. One research group from the University of Saskatchewan utilizes a DAQ known as the Lucid data acquisition and analysis system. This thesis examines the project undertaken to upgrade the hardware and software components of Lucid. To establish the effectiveness of the system upgrades, several performance metrics were obtained including the system's dead time and input/output bandwidth.<p>Hardware upgrades to Lucid consisted of replacing its aging digitization equipment with modern, faster-converting Versa-Module Eurobus (VME) technology and replacing the instrumentation processing platform with common, PC hardware. The new processor platform is coupled to the instrumentation modules via a fiber-optic bridging-device, the sis1100/3100 from Struck Innovative Systems.<p>The software systems of Lucid were also modified to follow suit with the new hardware. Originally constructed to utilize a proprietary real-time operating system, the data acquisition application was ported to run under the freely available Real-Time Executive for Multiprocessor Systems (RTEMS). The device driver software provided with sis1100/3100 interface also had to be ported for use under the RTEMS-based system. <p>Performance measurements of the upgraded DAQ indicate that the dead time has been reduced from being on the order of milliseconds to being on the order of several tens of microseconds. This increased capability means that Lucid's users may acquire significantly more data in a shorter period of time, thereby decreasing both the statistical uncertainties and data collection duration associated with a given experiment.

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