University of South Florida

About: University of South Florida is a education organization based out in Tampa, Florida, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 34231 authors who have published 72644 publications receiving 2538044 citations. The organization is also known as: USF.

Estimating Mean Sea Level Change from the TOPEX and Jason Altimeter Missions

Abstract: The Jason-2 satellite altimeter mission was launched in June 2008, extending the record of precision sea level measurements that was initiated with the launch of TOPEX/Poseidon in 1992 and continued with the launch of Jason-1 in December 2001. We have used the measurements from these three missions to construct a seamless record of global mean sea level change from 1993 to the present. We present the results of our calibration activities, including data comparisons during the “tandem period” of the missions, during which we solve for biases between the missions, as well as comparisons to independent tide gauge sea level measurements. When the entire record is assembled, the average rate of sea level rise from 1993–2009 is 3.4 ± 0.4 mm/year. There is considerable interannual variation due to ENSO-related processes, which include the period of lower sea level rise over the last three years of the time series during the recent La Nina event.

Enhancing the Interpretation of Significant Findings: The Role of Mixed Methods Research

Abstract: The present essay outlines how mixed methods research can be used to enhance the interpretation of significant findings. First, we define what we mean by significance in educational evaluation research. With regard to quantitative-based research, we define the four types of significance: statistical significance, practical significance, clinical significance, and economic significance. With respect to qualitative-based research, we define a significant finding as one that has meaning or representation. Second, we describe limitations of each of these types of significance. Finally, we illustrate how conducting mixed methods analyses can be used to enhance the interpretation of significant findings in both quantitative and qualitative educational evaluation and policy research. Consequently, mixed methods research represents the real "gold standard" for studying phenomena. Key Words: Quantitative Research, Qualitative Research, Mixed Methods, Significance, Meaning and Verstehen ********** Setting the Scene One argument posited by proponents of mixed methods studies is that they address much more comprehensive research purposes than do quantitative or qualitative research alone (Newman, Ridenour, Newman, & DeMarco, 2003). Consistent with this assertion, and expanding on Rossman and Wilson's (1985) work, Greene, Caracelli, and Graham (1989) categorized the following five general purposes of mixed-methodological studies: (a) triangulation (i.e., seeking convergence and corroboration of findings from different methods that study the same phenomenon); (b) complementarity (i.e., seeking elaboration, illustration, enhancement, and clarification of the findings from one method with results from the other method); (c) development (i.e., using the findings from one method to help inform the other method); (d) initiation (i.e., discovering paradoxes and contradictions that lead to a re-framing of the research question); and (e) expansion (i.e., seeking to expand the breadth and range of inquiry by using different methods for different inquiry components). As observed by Greene et al. (1989), every mixed methodological study can be classified as having one or more of these five purposes. In recent years, the advantages of mixed methods research have been increasingly recognized. In particular, as noted by Onwuegbuzie and Leech (in press), combining quantitative and qualitative research enables evaluation researchers to be more flexible and holistic in their investigative techniques, as they endeavor to address a range of complex research questions that arise. Further, mixed methods research helps investigators to develop a conceptual framework, to validate quantitative results by linking the information extracted from the qualitative phase of the study, and to construct indices from qualitative data that can be utilized to analyze quantitative data (Madey, 1982). Also, by conducting mixed methods studies, researchers are in a better position to combine empirical precision with descriptive precision (Onwuegbuzie, 2003a). In addition, by employing a pragmatist lens (i.e., using both quantitative and qualitative techniques), rather than using a single lens (i.e., conducting monomethod studies), investigators are able to zoom in to microscopic detail or to zoom out to indefinite scope (Willems & Raush, 1969). As such, mixed research investigations afford researchers with the opportunity to combine macro and micro levels of a study (Onwuegbuzie & Leech, in press). Compared to their monomethod counterparts, mixed methods researchers are more able to utilize quantitative research to inform the qualitative portion of research studies, and vice versa. For example, the inclusion of qualitative data can help investigators to explain relationships emerging from quantitative data. Similarly, the inclusion of quantitative data can help compensate for the fact that qualitative data typically cannot be generalized (Onwuegbuzie & Johnson, 2004). …

Enhanced Seebeck coefficient through energy-barrier scattering in PbTe nanocomposites

Abstract: Resistivity, Seebeck coefficient, and Hall measurements were performed on densified nanocrystalline composite materials of undoped and Ag-doped PbTe nanocrystals to investigate the physical mechanisms responsible for Seebeck coefficient enhancement in nanocrystalline systems. The unique temperature dependence of the resistivity and mobility for these PbTe nanocomposites suggests that grain-boundary potential barrier scattering is the dominant scattering mechanism. We propose that carrier trapping in the grain boundaries forms energy barriers that impede the conduction of carriers between grains, essentially filtering charge carriers with energy less than the barrier height. These nanocomposites therefore demonstrate an enhanced Seebeck coefficient as compared to single crystal or polycrystalline PbTe at similar carrier concentrations.

A new American Joint Committee on Cancer staging system for cutaneous melanoma.

Abstract: The Melanoma Staging Committee of the AJCC has proposed major revisions of the melanoma TNM and stage grouping criteria. The committee members represent most of the major cooperative groups and cancer centers worldwide with a special interest in melanoma; the committee also collectively has had clinical experience with over 40,000 patients. The new staging system better reflects independent prognostic factors that are used in clinical trials and in reporting the outcomes of various melanoma treatment modalities. Major revisions include 1) melanoma thickness and ulceration, but not level of invasion, to be used in the T classification; 2) the number of metastatic lymph nodes, rather than their gross dimensions, the delineation of microscopic versus macroscopic lymph node metastases, and presence of ulceration of the primary melanoma to be used in the N classification; 3) the site of distant metastases and the presence of elevated serum LDH, to be used in the M classification; 4) an upstaging of all patients with Stage I,II, and III disease when a primary melanoma is ulcerated; 5) a merging of satellite metastases around a primary melanoma and in-transit metastases into a single staging entity that is grouped into Stage III disease; and 6) a new convention for defining clinical and pathologic staging so as to take into account the new staging information gained from intraoperative lymphatic mapping and sentinel lymph node biopsy. The AJC Melanoma Staging Committee invites comments and suggestions regarding this proposed staging system before a final recommendation is made.