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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.
121

Interaction of the friction stir welding tool and work-piece as influenced by process parameters

Davis, Aaron Matthew 01 May 2010 (has links)
Friction Stir Welding (FSW) is a solid-state joining process that is of special interest in joining aluminum and other alloys that are traditionally difficult to fusion weld. The energy required for this joining process is transmitted to the work-pieces through a rotating FSW tool. Modeling attempts, aimed at perfecting the process, rely on assumptions of the contact conditions present between the work-pieces and the FSW tool. Various studies have attempted to define these contact conditions. Both theoretical and experimental studies indicate the contact conditions between the work-piece and weld tool are unknown and may vary during the FSW process. To provide insight into the contact conditions, the objective of this study is to characterize the FSW nugget in terms of swept volume as indicated by the cross-sectional area and symmetry of the FSW nugget over a range of processing conditions.
122

Thymidine Kinase 1: Diagnostic and Prognostic Significance in Malignancy

Alegre, Melissa Marie 07 June 2013 (has links) (PDF)
Thymidine kinase 1 (TK1) is a cancer biomarker which has diagnostic and prognostic potential in a variety of malignancies. TK1 is significantly elevated in the serum and tumor tissue of most malignancies. This increase in TK1 can be detected in the very early stages of malignancy, including in pre-malignant disease with an increased risk for progression. Several studies have demonstrated that elevated TK1 is found in serum months before any clinical symptoms of malignancy. It has also been demonstrated that TK1 is elevated months before clinical recurrence of malignancy. This work first sought to demonstrate the early nature of TK1 expression in breast tumor tissue and pre-malignant tissue. We found that TK1 is elevated in breast hyperplasia tissue and breast carcinoma tissue. In this study we also identified some cases of ‘normal’ tumor margins (considered normal by current pathological standards) which also had elevated TK1 expression. Conversely, true normal breast tissue from noncancerous individuals had no reported elevation in TK1 expression. This study illustrated that TK1 is elevated in pre-malignant breast hyperplasia tissue, as well as some 'normal' tumor margins. TK1 expression was significantly elevated in lung, prostate, colon, esophagus, stomach, liver, and kidney tissues. This work further investigated TK1 expression in a variety of malignant tissue including the two leading causes of cancer mortality in men: lung and prostate cancer. In our study, TK1 was significantly elevated in lung and prostate cancer but not significantly elevated in prostate hyperplasia tissue. TK1 expression also increased with increasing grade in prostate carcinoma tissue. Overall, this work demonstrated that TK1 is a good universal marker of malignancy and is elevated in early cancer development. Despite the potential for TK1 as both a screening and monitoring treatment tool, there have been significant challenges associated with developing a clinically relevant method of TK1 detection. This work proposes one clinically relevant method of detection, namely a TK1 ELISA. Using preoperable lung cancer patients and normal controls, we developed a sensitive and specific ELISA which shows highly statistically significant differences in serum TK1 levels between stage 1 and stage 2 lung cancer compared with normal controls. In fact, this TK1 ELISA is more sensitive and accurate than the traditional TK radioassay, which was unable to detect differences in TK1 between early stage lung cancer and normal patients. Although elevated TK1 is not lung cancer specific, we reported significantly elevated TK1 levels in lung cancer sputum. Screening of sputum and serum for TK1 may be one method for the early detection of lung cancer. Overall, we report TK1 has promising diagnostic potential in a variety of malignancies. We also propose one sensitive and specific method to detect TK1 levels which may easily be adapted to meet current clinical applications. We hope this work will help propel TK1 forward into clinical view in the coming years.
123

The Development and Testing of a Measurement System to Assess Intensive Care Unit Team Performance

Dietz, Aaron 01 January 2014 (has links)
Teamwork is essential for ensuring the quality and safety of healthcare delivery in the intensive care unit (ICU). Complex procedures are conducted with a diverse team of clinicians with unique roles and responsibilities. Information about care plans and goals must also be developed, communicated, and coordinated across multiple disciplines and transferred effectively between shifts and personnel. The intricacies of routine care are compounded during emergency events, which require ICU teams to adapt to rapidly changing patient conditions while facing intense time pressure and conditional stress. Realities such as these emphasize the need for teamwork skills in the ICU. The measurement of teamwork serves a number of different purposes, including routine assessment, directing feedback, and evaluating the impact of improvement initiatives. Yet no behavioral marker system exists in critical care for quantifying teamwork across multiple task types. This study contributes to the state of science and practice in critical care by taking a (1) theory-driven, (2) context-driven, and (3) psychometrically-driven approach to the development of a teamwork measure. The development of the marker system for the current study considered the state of science and practice surrounding teamwork in critical care, the application of behavioral marker systems across the healthcare community, and interviews with front line clinicians. The ICU behavioral marker system covers four core teamwork dimensions especially relevant to critical care teams: Communication, Leadership, Backup and Supportive Behavior, and Team Decision Making, with each dimension subsuming other relevant subdimensions. This study provided an initial assessment of the reliability and validity of the marker system by focusing on a subset of teamwork competencies relevant to subset of team tasks. Two raters scored the performance of 50 teams along six subdimensions during rounds (n=25) and handoffs (n=25). In addition to calculating traditional forms of reliability evidence [intraclass correlations (ICCs) and percent agreement], this study modeled the systematic variance in ratings associated with raters, instances of teamwork, subdimensions, and tasks by applying generalizability (G) theory. G theory was also employed to provide evidence that the marker system adequately distinguishes teamwork competencies targeted for measurement. The marker system differentiated teamwork subdimensions when the data for rounds and handoffs were combined and when the data were examined separately by task (G coefficient greater than 0.80). Additionally, variance associated with instances of teamwork, subdimensions, and their interaction constituted the greatest proportion of variance in scores while variance associated with rater and task effects were minimal. That said, there remained a large percentage of residual error across analyses. Single measures ICCs were fair to good when the data for rounds and handoffs were combined depending on the competency assessed (0.52 to 0.74). The ICCs ranged from fair to good when only examining handoffs (0.47 to 0.69) and fair to excellent when only considering rounds (0.53 to 0.79). Average measures ICCs were always greater than single measures for each analysis, ranging from good to excellent (overall: 0.69 to 0.85, handoffs: 0.64 to 0.81, rounds: 0.70 to 0.89). In general, the percent of overall agreement was substandard, ranging from 0.44 to 0.80 across each task analysis. The percentage of scores within a single point, however, was nearly perfect, ranging from 0.80 to 1.00 for rounds and handoffs, handoffs, and rounds. The confluence of evidence supported the expectation that the marker system differentiates among teamwork subdmensions. Yet different reliability indices suggested varying levels of confidence in rater consistency depending on the teamwork competency that was measured. Because this study applied a psychometric approach, areas for future development and testing to redress these issues were identified. There also is a need to assess the viability of this tool in other research contexts to evaluate its generalizability in places with different norms and organizational policies as well as for different tasks that emphasize different teamwork skills. Further, it is important to increase the number of users able to make assessments through low-cost, easily accessible rater training and guidance materials. Particular emphasis should be given to areas where rater reliability was less than ideal. This would allow future researchers to evaluate team performance, provide developmental feedback, and determine the impact of future teamwork improvement initiatives.
124

Ballcourt Iconography At Caracol, Belize

Holden, Patsy 01 January 2009 (has links)
One of the more commonly known aspects of the ancient Maya culture is the ballgame. This ancient ballgame was played by most Mesoamerican cultures on a constructed ballcourt and many major Mesoamerican sites have at least one, if not more than one. Contemporary Mesoamericans still play versions of this ballgame today, but without the use of the ballcourts, questioning the importance and purpose of the ballcourt that is no longer the case today. After over a century of research, scholars have yet to unravel all the cosmological and mythological mysteries of the ballcourt and its purpose to the ancient Maya. Although the archaeological record rarely supports the well-known Postclassic Hero Twin myth, most scholars continue to use this myth to interpret Classic ballgame iconography. In this study, I link Classic period ballcourt architecture and iconography at Caracol to Preclassic cache practices, to an Early Classic tomb, and to an elite Classic structure, demonstrating a widespread set of cosmological symbols that were not exclusively reserved for the ballcourt. I suggest that the four eroded figures on Caracol Ballcourt Markers 1 and 2 represent east, west, zenith, and nadir, and that the north-south alignment of Classic Southern Lowland ballcourts was the result of a vertical visualization of the three ballcourt markers. This study shows that the Maya ballcourt was a cosmogram, intended to delineate sacred space and demarcate a portal into the underworld.
125

Trends in Grave Marker Attributes in Greenwood Cemetery: Orlando, Florida

Martin, Erin K 01 January 2018 (has links)
Grave markers represent a significant amount of highly important information related to the cultural patterns of a society, as well as how these patterns have changed over time. Although, cemetery studies are popular in other regions of the United States, few studies regarding grave marker attributes have been conducted in Florida. The purpose of this research was to analyze and interpret temporal and demographic changes in grave marker attributes in Greenwood Cemetery in Orlando, Florida. Another aspect of this research focused on the possible correlation between the age and inferred sex of the deceased individual in relation to the type of epitaph and iconography chosen to represent them in their mortuary context. Data was collected from 925 headstones within Greenwood Cemetery; these headstones further represent 1,102 individuals. Attributes analyzed include marker material, marker type, iconographic images, epitaph, memorial photographs, footstones and curbs. These attributes will be analyzed and compared to trends noted within a similar study conducted by Meyers and Schultz (2016), to allow for better interpretation of trends in grave marker attributes across a range of Florida cemeteries. Results indicate multiple trends. The popularity of marble headstones decreased greatly from 51% in Pre-1900 to only 8% from 2000 to 2017. Furthermore, the prevalence of epitaph and iconography categories vary greatly on both a temporal and demographic basis. Male infants are more likely than any other demographic group to be represented by a genealogical epitaph, at 41% representation. Ultimately, these trends illustrate important aspects of cultural changes related to mortuary practice and individual mortuary contexts within Orlando, Florida.
126

L’EXPLORATION DU QUOTIDIEN DANS CHATS PERCHÉS DE CHRIS MARKER

Talpin, Emilie V. 31 January 2008 (has links)
No description available.
127

Characterization of <i>Pneumocystis carinii</i>Subcellular Fractions

HUNT, SHANNON MICHELE 02 October 2006 (has links)
No description available.
128

An investigation of the associations between several candidate genes and reproductive traits in swine

Isler, Bradley J. 29 January 2003 (has links)
No description available.
129

Morpholotical and genetic variation within perennial ryegrass (lylium perenne l.)

Liu, Jianyang 10 October 2005 (has links)
No description available.
130

Genetic characterization of partial resistance and comparative strategies for improvement of host-resistance to multiple foliar pathogens of maize

Asea, Godfrey Rox January 2005 (has links)
No description available.

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