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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.
21

Identifying key factors in two-dimensional crystal production and sample preparation for structure-function studies of membrane proteins by cryo-EM

Johnson, Matthew C. 12 January 2015 (has links)
Electron crystallography of two-dimensional crystals is a structure-determination method well suited to the study of membrane protein structure-function. Two-dimensional crystals consist of ordered arrays of protein within reconstituted lipid bilayers, an arrangement that mimics the natural membrane environment. In this work we describe our recent progress in the use of this method with three different proteins, each providing a window into a separate paradigm in the electron crystallographic pipeline. Specific crystallization conditions for human leukotriene C₄ synthase (LTC₄S) have previously been determined, but our continued refinement of purification and crystallization has identified a number of additional parameters that greatly affect crystal size and quality, and we have developed a protocol to rapidly and reproducibly grow large, non-mosaic crystals of LTC₄S. The human gamma-glutamyl carboxylase (GGCX) has also been crystallized, but is sensitive to cryo-EM sample preparation conditions and we present here the successful reproduction of crystallization and refinement of cryo-EM sample preparation conditions. Lastly, we describe our crystallization screens with the Vibrio cholerae sodium-pumping NADH:ubiquinone reductase complex (Na⁺-NQR), and identify the factors critical to membrane reconstitution of the complex, a necessary first step towards crystallization. We also describe a semi-quantitative crystal screening protocol we have developed that provides quick and accurate method to assess two- dimensional crystallization trials, and discuss some general observations in optimization of membrane protein purification and two-dimensional crystallization for electron crystallography.
22

Understanding complex CI-combustion strategies : an experimental investigation

Michailidis, Antonis D. January 2012 (has links)
Within this body of work several series of experiments will investigate the nature of complex combustion in an experimental single-cylinder engine emulating a modern passenger car size compression-ignition (CI) engine. Regimes of single, piloted single and piloted split-main injections will be tested and compared in terms of combustion characteristics, specific emission output and cyclic behaviour to determine how increased injection complexity affects the emissions and output of the modern CI engine. Through these tests, the effect of fuel-line stationary waves will be demonstrated and investigated, showing conclusively that optimised engine calibration is essential to account for injector-generated waves in any multiple injection scenario. This data will then be confirmed with a dedicated analysis using an injector rate measuring tube. The tests will then be expanded to include examination into the behaviour of injector needle-lift standard deviation over its operating cycle, in-cylinder pressure standard deviation behaviour and trends over the combustion cycle as well as IMEP variability. Through these tests a novel method to detect start of combustion will be proposed and compared to conventional methods. Low temperature combustion (LTC) will be tested under incremental injection complexity. Tests will be optimised for combustion phasing and injection pressure, with a view to analysis of emissions, output and cyclic behaviour to establish whether the knowledge gained about conventional combustion holds true under LTC. Optimization of engine parameters will be shown to result in easier to implement LTC regimes with superior emissions characteristics. Finally, LTC tests will be expanded to include 30% and 50% by volume gas-to-liquid fuel (GTL) blends in order to determine whether fuel characteristics further influence emissions, output and cyclic behaviour in LTC through complex injection regimes. How GTL-blend ratio affects trends in emissions and cyclic behaviour will also be examined and compared to conventional diesel fuel.
23

[en] AN IMPROVED STEADY-STATE MODEL FOR TAP-CHANGING TRANSFORMER / [pt] NOVO MODELO DE TRANSFORMADOR COM TAP VARIÁVEL EM REGIME PERMANENTE

CARLOS APARECIDO FERREIRA 25 June 2013 (has links)
[pt] O fenômeno de estabilidade de tensão vem despertando grande interesse acadêmico e das principais empresas de energia elétrica do mundo desde que começou a ser observado em sistemas reais, no final da década de setenta. Sua ocorrência está relacionada ao carregamento excessivo das linhas de transmissão. Modelar transformador com tap variável adequadamente é fundamental em análises de estabilidade de tensão, tanto no que diz respeito às informações fornecidas ao operador referentes às margens de estabilidade de tensão, quanto aos efeitos de ações de controle de tensão. O modelo de transformador com tap variável utilizado mundialmente consiste de uma impedância, obtida através do ensaio em curto-circuito e com tap nominal, em série com um transformador ideal. Esta tese mostra que, em estudos de estabilidade de tensão, o uso desse modelo leva a resultados qualitativamente errados. Para demonstração, utiliza-se um circuito pequeno e os conceitos de máxima potência transmitida, impedância equivalente da carga, e efeito do controle de tensão. Propõe-se um novo modelo coerente com os resultados obtidos em laboratório, com as leis de circuitos elétricos e com a teoria de estabilidade de tensão. Esse modelo pode ser utilizado em qualquer estudo em regime permanente. Através de diversas simulações computacionais, diferenças quantitativas e principalmente qualitativas foram obtidas comparando-se os resultados dos dois modelos. / [en] The voltage stability phenomenon is of interest since it began to be observed in real systems in the late seventies. It happens due to excessive loading of transmission lines. The modeling of tap-changing transformers is fundamental in voltage stability analysis, in terms of the information provided to the operator about voltage stability margins and the effects of voltage control actions. The model for tap-changing transformers currently in widespread use consists of an impedance, measured in a short-circuit test with a nominal tap, in series with an ideal transformer. The use of this model in voltage stability studies leads to qualitatively incorrect results, as shown in this thesis. For demonstration purpose a small circuit and the concepts of maximum load, equivalent load impedance and voltage control effects are used. An improved model that takes into account laboratory results, circuit laws and voltage stability theory is proposed. This model can be used in any steady-state study. It gives results that are not only more accurate than those obtained with the conventional model, but also, as shown in this thesis, qualitatively different.
24

Systém managementu kvality dlouhodobé péče v ČR / Quality Management System for Long-Term Care (LTC) in the Czech Republic

Waageová, Alena January 2011 (has links)
The aim of this thesis is to analyze Long-Term Care in the Czech Republic, to design a Quality Management System for Long-Term Care, and to demonstrate its practical application in Gerontological Centre. A Quality Management Handbook for Long-Term Care represents an additional aim of this thesis; it is designed for Health and Social organizations having a similar spectrum of activities. This work relies on document analysis - available scientific studies on long-term care, and literature focused on quality management. A significant part of the text is supported by our own practical experience and is reinforced by consultations with experts in senior care. ISO systems, TQM approaches, Standards of social services, and National accreditation standards for subsequent and long-term care SAK ČR (United Accreditation Commission of Czech Republic) have been used as a starting point for the proposed Quality Management System. The proposed system has a broad scope, including resources, processes and outputs. The systems used in practice have some common parts; therefore the proposed model may be easily modified to accommodate the specific requirements of individual certification authorities.
25

COMBUSTIÓN POR DIFUSIÓN DE BAJA TEMPERATURA EN MOTORES DIESEL DE PEQUEÑA CILINDRADA

Jorge Amorim, Rogério 22 November 2010 (has links)
Las estrategias de combustión de baja temperatura han sido el foco de diversos estudios con el fin de lograr una combustión en un motor Diesel más limpia en términos de emisión de contaminantes. En sus diversas variantes pueden presentar mejoras respecto principalmente a las emisiones de NOX y hollín, pero presentan limitación en cuanto a grado de carga y ruido de la combustión. Hace unos años, se presentó un nuevo concepto de combustión Diesel de baja temperatura (LTC) que confirma una reducción simultánea de NOX y hollín, manteniendo las características de una combustión por difusión. Esta nueva modalidad, desarrollada entonces en una cámara de combustión a volumen constante, consistía en crear un ambiente con baja temperatura y baja concentración de oxígeno en el aire combinado con el uso de alta presión de inyección y toberas con diámetro de orificios reducidos. De esta forma, se consiguió reducir la temperatura adiabática de llama y aumentar el englobamiento de aire aguas arriba de la longitud de lift-off, evitando la formación de los dos contaminantes simultáneamente. El objetivo de esta tesis ha consistido en trasladar esta nueva tecnología de combustión LTC por difusión a un motor convencional de baja cilindrada unitaria, enfrentando los obstáculos que surgen cuando se aplica el concepto a un motor real, como el choque de pared, la dificultad en controlar las condiciones del ambiente dentro del cilindro y el acortamiento de la longitud de lift-off, que reduce el englobamiento de aire en la llama. En la primera parte, se ha buscado lograr la combustión LTC estrictamente por difusión en dos motores de características geométricas diferentes y entender las influencias de los parámetros termodinámicos del gas en el cilindro, como la concentración de oxígeno, la temperatura y la densidad. Finalmente, se ha explorado cómo los parámetros relacionados con el diseño y funcionamiento del sistema de inyección, tales como el diámetro del orificio de la tobera, número de orificios y presión de inyección, podrían mejorar el proceso de combustión, con el objetivo de extender el rango de combustión LTC. Los resultados muestran el potencial de este concepto de combustión, habiéndose obtenido emisiones de NOX y hollín prácticamente nulas, con una penalización en la presión media indicada poco importante. Sin embargo hay algunos aspectos de este concepto de combustión que deben ser mejorados para poder implementar su utilización en motores de serie, algunos de los cuales son expuestos en esta tesis. / Jorge Amorim, R. (2010). COMBUSTIÓN POR DIFUSIÓN DE BAJA TEMPERATURA EN MOTORES DIESEL DE PEQUEÑA CILINDRADA [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8951 / Palancia
26

Caregiver Burnout, Compassion Satisfaction, and Personality: The Moderating Role of Work Engagement and Job Satisfaction

Richert, Mallory 06 July 2021 (has links)
No description available.
27

Health Information Technology and Elderly Care: Older Adults' and Long-Term Care Nurses' Perspectives on Technology Adoption and Impacts

Kavandi, Hamidreza 05 April 2023 (has links)
The population of older adults is growing worldwide, particularly in North America. Health information technology (HIT) is a group of technologies and systems that enhance care by electronically storing, managing, and exchanging data. HIT presents opportunities to support older adults' healthcare needs in communities and long-term care (LTC) environments. Despite their potential benefits, these technologies remain limited in LTC and older adults' healthcare contexts. Evidence is scattered on the factors that affect older adults' adoption of HIT. Little research has investigated the adoption of these technologies by formal healthcare providers and the technologies' impacts on LTC. A multi-method approach was employed in this thesis research, using a combination of a systematic qualitative review, an inductive semi-qualitative Delphi survey, and a quantitative deductive study to manage each research question in order to address these gaps. The systematic literature review used the PRISMA guidelines to identify and critically appraise studies that examined the effect of various HIT adoption factors among older adults in the community. The search involved five databases and a combination of keywords, resulting in the selection of critically appraised articles based on their evidence level and research rigor. A coding scheme was developed to extract information from the selected articles. The results showed that the main factors affecting HIT adoption by older adults relate to performance expectancy, effort expectancy, and high price/cost value. It also highlighted the importance of considering privacy/security and product design when evaluating HIT adoption by older adults. In light of the limited available studies on HIT adoption and impacts in the context of LTC, a Delphi study was developed to collect data from key formal healthcare providers (i.e., nurses) working in LTC at one of the largest and most progressive older adult healthcare facilities in Ontario, Canada. The Delphi study aimed to identify and prioritize the key factors that affect nurses' adoption of new technologies in support of older adults' care. A panel of nurses was solicited to participate in the Delphi study, which involved three rounds of data collection: brainstorming, narrowing down, and ranking. A total of 20 nurses completed the Delphi study, and the top factors that the LTC nurses identified were mainly related to the organizational and technological dimensions, including the complexity of HIT, the training and support provided, the interoperability of HIT systems, the cost of implementation, and the availability of HIT infrastructure. For the last part of this research, quantitative secondary data analysis was conducted on a Canadian national survey of nurses to examine their perceived impacts of HIT adoption by nurses in LTC. The survey included questions related to the current state of electronic medical records (EMR) and EMR adoption, the state of virtual care technologies, attitudes and perceptions related to access and the impact of the adoption of digital health technologies in practice, benefits and effects of EMR adoption, and barriers preventing nurses from getting total value from electronic health. A subset of 166 nursing homes/long-term care facilities/older adult residences and homecare nurses were selected for this analysis. Data management and analysis were conducted using IBM SPSS v28. The results showed that HIT adoption by nurses in LTC was positively associated with perceived benefits and organizational support. However, HIT adoption was negatively associated with perceived complexity and privacy/security concerns. This thesis research suggests that HIT adoption by older adults and nurses in LTC is complex and multifaceted, requiring attention to individual, organizational, and technological factors. There is a need for improved communication and collaboration among LTC team members and better working conditions to improve staff well-being and reduce turnover. The findings from the systematic review and Delphi study contribute to the theoretical understanding of the factors influencing the adoption of HIT in LTC facilities. The survey results provide valuable insights into the current state of HIT use in LTC facilities and can be used to inform the development of targeted interventions to improve HIT adoption and use. Overall, this study contributes to the growing body of knowledge on HIT adoption in LTC facilities and provides important recommendations for policymakers, administrators, and LTC staff to improve the use of HIT and ultimately enhance the quality of the care supplied to LTC residents.
28

Distinctions between High and Low Performing Ohio Nursing Homes

Qiu, Xiao, Qiu 01 August 2017 (has links)
No description available.
29

[pt] ANÁLISES ESTÁTICA E DINÂMICA DA ATUAÇÃO DE EQUIPAMENTOS DE CONTROLE NA ESTABILIDADE DE TENSÃO / [en] STATIC AND DYNAMIC ANALYSES OF CONTROL DEVICE EFFECTS ON VOLTAGE STABILITY

MARCOS VINICIUS PIMENTEL TEIXEIRA 19 October 2016 (has links)
[pt] O problema da estabilidade de tensão está associado à máxima injeção de potência em barras da rede e à possibilidade do controle de tensão ter o efeito oposto ao esperado. Alguns casos reais de blecaute, caracterizados por afundamento de tensão, sugerem que os procedimentos normais para o controle de tensão do sistema podem agravar ainda mais o problema. Isso ocorreria porque, em determinadas situações especiais, caracterizadas pela relação inversa entre as variáveis de controle dos equipamentos, as ações de controle teriam o efeito oposto ao esperado da sua lógica de projeto. Esta afirmação é baseada no critério de estabilidade de tensão a pequenas perturbações que diz: Dada uma condição de operação para cada barra no sistema, o sistema é estável caso o módulo da tensão na barra aumente à medida que a injeção de potência reativa nessa mesma barra é aumentada. Um sistema é instável se, para pelo menos uma barra no sistema, o módulo de tensão da barra diminui conforme a injeção de potência reativa nessa barra é aumentada. Adicionalmente, o critério da curva 𝑉𝑄 diz: Uma vez que todos os dispositivos de controle de potência reativa são projetados para funcionar satisfatoriamente quando um aumento em 𝑄 é acompanhado por um aumento em 𝑉, a operação do lado direito das curvas 𝑉𝑄 é estável e do lado esquerdo é instável. Além disso, a parte inferior da curva 𝑉𝑄 representa o limite de estabilidade e define o valor de potência reativa mínimo para uma operação estável. Esse efeito não esperado do controle poderia causar tensões excessivamente baixas (ou altas) para a operação normal do sistema e provocar consequências indesejáveis. Visto isso, esse trabalho tem como principal objetivo investigar, no domínio do tempo, o efeito das ações de controle de tensão em pontos onde as variáveis de controle dos equipamentos apresentam relação inversa e, assim, validar (ou não) os resultados estimados pelos métodos baseados em análise estática como, por exemplo, os critérios de estabilidade de tensão a pequenas perturbações e da curva 𝑉𝑄. As simulações dinâmicas mostram que a análise estática não pode ser aplicada a todos os tipos de equipamentos que controlam a tensão. Outra possível causa do problema da estabilidade de tensão está relacionada à atuação de limitadores de sobre-excitação de máquinas síncronas e, por esta razão, é proposto um método para identificar as máquinas propensas a atingir o limite de sobre-excitação em estudos de regime permanente. No entanto, a atuação desses limitadores, na grande maioria das vezes, não apresenta efeito prejudicial na estabilidade do sistema e, por isto, também é proposto um critério que aponta a iminente perda da estabilidade devido à atuação dos limitadores. Este critério pode ser útil na concepção de esquemas automáticos de rejeição de carga, a fim de impedir a perda de estabilidade, e ele também pode ser utilizado em avaliações de segurança online para alertar sobre possíveis riscos de instabilidade e, consequentemente, para indicar ações preventivas. / [en] The voltage stability problem is associated with the maximum power injection in the network and the possibility of the voltage control having the opposite effect. Some real cases of blackouts characterized by voltage decays suggest that normal procedures for automatic voltage control can adversely affect the voltage level in the system. This may have been because in special situations, characterized by an inverse relationship between the controls variables in the devices used to control the system voltage, the automatic voltage control can have the opposite effect to that expected based on the design logic. This statement is based on the criterion for small-disturbance voltage stability: At a given operating condition for every bus in the system, a system is voltage-stable if the bus voltage magnitude increases as the reactive power injection at the same bus is increased. A system is voltage-unstable if, for at least one bus in the system, the bus voltage magnitude decreases as the reactive power injection at the same bus is increased. In addition, it is based on the 𝑉𝑄 curve criterion: Since all reactive power control devices are designed to operate satisfactorily when an increase in 𝑄 is accompanied by an increase in 𝑉, operation on the right side of the 𝑉𝑄 is stable and on the left side is unstable. Besides, the bottom of the 𝑉𝑄 curve represents the stability limit and defines the minimum reactive power requirement for stable operation. The unexpected control effect could produce excessively low (or high) voltages for normal system operation and cause undesirable consequences. In light of this, the present work seeks to analyze in the time domain the effects of device control actions starting from points where the control variables are inversely related and validated (or not) the results estimated by methods based on static analysis, for example, the criterion for small-disturbance voltage stability and 𝑉𝑄 curve. Dynamic simulations show that static analysis cannot be applied to all types of devices used to control the voltage. Another possible cause of the voltage stability problem is the action of overexcitation limiters. For this reason, it is proposed a way for identifying the machines that have a chance to hit the overexcitation limit in static analysis studies. However, in most cases, the action of these limiters has no detrimental effect on system stability and, therefore, it is also proposed a criterion that identifies the imminent loss of stability due to these limiters. This criterion may be useful in design of load shedding schemes, in order to prevent loss of stability, and can be used for online security assessment, warning for instability and indicating preventive actions.
30

Organiser le maintien à domicile des personnes âgées dépendantes : une comparaison du travail des professionnels en France et en Corée / Organizing home welfare services for the dependent elderly : a comparative study on the work of "second line" professionals in gerontology in France and Korea

Park, Haemi 03 December 2013 (has links)
Avec l'instauration, en 2002 en France, de l'Allocation Personnalisée à l'Autonomie (APA), et en 2008 en Corée, du dispositif Long Term Care (LTC), la prise en charge de la dépendance de la population âgée s'affirme comme un enjeu majeur de la politique sociale contemporaine de ces deux pays confrontés au phénomène du vieillissement démographique. En dépit de contextes démographiques, historiques, culturels, politiques, économiques et sociaux contrastés, ces deux pays ont en commun de mettre en place, pour faire face aux besoins des personnes âgées, des dispositifs dont les logiques d'action paraissent proches ou sensiblement similaires. En adoptant une optique comparative entre la France et la Corée, cette thèse cherche à mettre en regard le travail des professionnels socio-gérontologiques chargés de la mise en œuvre de ces dispositifs en faveur de la population âgée dite dépendante à domicile. Pour cela les procédures mises en place dans le cadre de l'APA en France et du LTC en Corée et la manière dont l'accompagnement socio-médical des personnes âgées dépendantes à domicile s'y organise ont été étudiées. Tant en France qu'en Corée, les professionnels qui interviennent pour assurer le maintien à domicile des personnes âgées dépendantes sont multiples ; les uns travaillent en "première ligne" (aides à domicile, auxiliaires de vie, aides soignants, infirmiers) et les autres, chargés de la coordination et de l'encadrement des précédents, en "seconde ligne". Elle traite également de la nécessaire - et difficile - coordination entre ces professionnels et des logiques, parfois divergentes et conflictuelles, qui sous-tendent leurs actions dans des réalités organisationnelles complexes. L'observation a été effectuée sur un territoire circonscrit dans chacun des deux pays : Lille-Hellemmes pour la France et Cheongju-Cheongwon pour la Corée. / With the establishment of the Individual Public Allowance for Autonomy (APA) in France in 2002 and the Long Term Care (LTC) insurance in Korea in 2008, the management and the support for the dependence of the elderly population became a major issue of contemporary social policy in these two nations faced with the phenomenon of aging. Despite demographic, historical, cultural, political, economical and social contrasting contexts, they have installed devices in common with modes that appear close or substantially similar to cope with the increasing needs of the elderly. By adopting a comparative approach between France and Korea, this thesis sought to analyze the work of social gerontological professionals in charge of these devices for the elderly dependent who stay at home. For this, the application procedure of the APA in France and the LTC in Korea and the organization of the socio-medical asistance for the dependent elderly at home were studied. In both France and Korea, the professionals who are involved with the home care services are multiple. Some are working in the "front line" (home helpers, care assistance, home nurses) and others are occupied with the coordination, the supervision/organization of the foregoing (front line workers) in the "second line". This research focuses on the impact of devices which are placed on the work of professionals, especially those who are concerned with various tasks in the second line and their necessary - and difficul t- coordination. How the different policies and the strategic relationship between these various participating professionals sometimes diverge and how the conflicts intrinsic to their actions and practice within complex organizational realities are settled were investigated and explored. The observation was carried out in one area within each country : Hellemmes-Lille in France and Cheongju-Cheongwon in Korea.

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