East Carolina University

About: East Carolina University is a education organization based out in Greenville, North Carolina, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 11091 authors who have published 22389 publications receiving 635008 citations. The organization is also known as: ECU & East Carolina.

Refractive indices of human skin tissues at eight wavelengths and estimated dispersion relations between 300 and 1600 nm

Abstract: The refractive index of human skin tissues is an important parameter in characterizing the optical response of the skin. We extended a previously developed method of coherent reflectance curve measurement to determine the in vitro values of the complex refractive indices of epidermal and dermal tissues from fresh human skin samples at eight wavelengths between 325 and 1557 nm. Based on these results, dispersion relations of the real refractive index have been obtained and compared in the same spectral region.

Attrition in Online and Campus Degree Programs.

Abstract: The purpose of this study was to examine how the mode of instructional delivery, campus face-to-face or online, affected dropout relative to students’ academic and demographic characteristics. A quantitative study was conducted to analyze the academic and demographic characteristics of newly admitted, matriculated degree-seeking students (N = 640) from Fall 2002 to Fall 2004 in the Master’s of Business Administration and Master’s in Communication Sciences and Disorders at a national research university in the southeastern United States. Demographic variables analyzed were age, gender, and ethnicity. Academic variables analyzed were program delivery mode, undergraduate grade point average, graduate grade point average at time of dropout or completion, admission test scores, and number of terms to degree completion or number of courses completed at time of dropout. Results of the study found that online students were significantly more likely to dropout than campus based students. Age was found to have a significant unique affect on dropout in both programs with older students more likely to dropout. Academic and demographic variables were not found to be significantly associated with dropout in the online formats of either program. Variables related to dropout for the campus based groups of both programs differed. Campus MBA students who dropped out were older and had higher GMAT scores while campus CSDI students who dropped out had lower undergraduate GPA’s and GRE scores. Logistic regression analyses showed age and delivery format to have significant unique effects beyond other predictors on dropout in the MBA program overall while age and undergraduate GPA had significant unique effects beyond other predictors on dropout for the CSDI program. Introduction To provide greater access to students and to meet market demands, institutions of higher education are adopting online delivery of instruction at the course and program level at a rapid pace. Offering benefits to both students and institutions, online instruction has become a very attractive choice for teaching and learning. According to a recent survey, almost 3.9 million students were enrolled in at least one online class during the fall of 2007. The 12.9% growth rate for online enrollment is much greater that the 1.2% growth overall of the higher education student population (Allen & Seaman, 2008). The accelerated growth of online instruction has been accompanied by questions of quality in terms of outcomes. One measure of program quality and effectiveness is program completion rates. Although studies have shown the effectiveness of instruction in the online environment to be comparable to that of the traditional classroom environment (Russell, (2001), studies and anecdotal evidence indicate high attrition rates for online courses, often much higher than for campus courses (Bos & Shami, 2006; Diaz & Cartnal, 2006; Rovai, 2003; Willging & Johnson, 2004). Adult students have been reported to have lower retention rates in campus programs than traditional aged students which has implications for distance education programs since enrollment in these programs is predominantly adult students, particularly at the graduate level (Rovai). Institutions are being held increasingly accountable to legislative bodies, governing boards, and the federal government with respect to program outcomes, one of which is program completion rates. It is important for institutions to report high retention rates in order to secure funding. Institutions continue to believe that distance education is “critical” to their long-term strategy and survival (Allen & Seaman, 2008). Methodology The purpose of this study was to examine how the mode of instructional delivery, campus face-to-face or online, affected dropout relative to students’ academic and demographic characteristics. Specifically, this study answered the following research questions: To what extent does the dropout rate vary by instructional delivery mode, online versus campus face-to-face, for each selected master’s degree program? 1. What are the demographic and academic characteristics significantly associated with student persistence or dropout in master’s degree programs? 2. How do the demographic and academic variables significantly associated with student dropout differ between the two delivery modes, online versus face-to-face? 3. A quantitative study was conducted to analyze the academic and demographic characteristics of newly admitted, matriculated degree-seeking students (N = 640) from Fall 2002 to Fall 2004 in the Master’s of Business Administration and Master’s in Communication Sciences and Disorders at a national research university in the southeastern United States. Demographic variables analyzed were age, gender, and ethnicity. Academic variables analyzed were program delivery mode, undergraduate grade point average, graduate grade point average at time of dropout or completion, admission test scores, and number of terms to degree completion or number of courses completed at time of dropout. The campus and online formats of the programs were for the most part identical with the exception of delivery mode. The online and campus formats of each of the selected programs were based in the same academic departments and utilized the same professors, curriculum, assignments, campus technology and infrastructure and campus academic support services; thereby, offering some degree of control for intervening program, instructional, and institutional variables. The researchers studied individual student enrollment records in the student database and determined student enrollment status (completer-obtained degree within the time frame; persister-did not achieve degree completion but continued enrollment without being out for more than one academic term; or dropout – initially admitted and enrolled during the study but were not enrolled at the conclusion and who had not been enrolled for two consecutive academic terms). Students were classified as online students if more than 50% of their completed courses were delivered online and students were classified as campus students if more than 50% of their courses were on campus in face-to-face classes. If a student had an equal number of classes in each format, the number of credit hours attempted on each campus were used to determine the primary campus of enrollment.

The postantibiotic effect.

Abstract: The factors that affect the presence and duration of the post-antibiotic effect (PAE) for different antimicrobial agents are described, and the clinical importance of the PAE is discussed. Proposed mechanisms by which the PAE occurs include both nonlethal damage induced by the antimicrobial agent and a limited persistence of the antimicrobial agent at the bacterial binding site. The specific microorganism-antimicrobial combination is the most important factor to influence the presence and duration of the PAE. Additional factors are antimicrobial combinations and experimental conditions, including the antimicrobial concentration and the length of the antimicrobial exposure. Most antimicrobial agents produce a PAE when tested against gram-positive cocci. However, against gram-negative bacilli, beta-lactam antibiotics (except for imipenem) have a minimal, or even a negative, PAE. Aminoglycosides, inhibitors of protein and nucleic acid synthesis, and fluoroquinolones have PAEs against gram-negative bacteria that range from one to four hours. In vivo PAEs are generally longer than in vitro PAEs for the same microorganism-antimicrobial combination. In human studies, aminoglycosides, which have an extended PAE against gram-negative bacilli, have been effective when given in once-daily dosing regimens that allow serum drug concentrations to fall below the minimum inhibitory concentration. Extending the dosing interval of an antimicrobial agent that has a PAE has several potential advantages, among them reduced cost, less toxicity, and better compliance among outpatients receiving antimicrobial therapy. Although data are limited, animal and human studies provide support for the clinical importance of the PAE. Further research into the impact of the PAE on antimicrobial dosing, efficacy, toxicity, and costs is warranted.

Peat Bog Wildfire Smoke Exposure in Rural North Carolina Is Associated with Cardiopulmonary Emergency Department Visits Assessed through Syndromic Surveillance

Abstract: Background: In June 2008, burning peat deposits produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina. Although the association of mortality and morbidity with exposure to urban air pollution is well established, the health effects associated with exposure to wildfire emissions are less well understood. Objective: We investigated the effects of exposure on cardiorespiratory outcomes in the population affected by the fire. Methods: We performed a population-based study using emergency department (ED) visits reported through the syndromic surveillance program NC DETECT (North Carolina Disease Event Tracking and Epidemiologic Collection Tool). We used aerosol optical depth measured by a satellite to determine a high-exposure window and distinguish counties most impacted by the dense smoke plume from surrounding referent counties. Poisson log-linear regression with a 5-day distributed lag was used to estimate changes in the cumulative relative risk (RR). Results: In the exposed counties, significant increases in cumulative RR for asthma [1.65 (95% confidence interval, 1.25–2.1)], chronic obstructive pulmonary disease [1.73 (1.06–2.83)], and pneumonia and acute bronchitis [1.59 (1.07–2.34)] were observed. ED visits associated with cardiopulmonary symptoms [1.23 (1.06–1.43)] and heart failure [1.37 (1.01–1.85)] were also significantly increased. Conclusions: Satellite data and syndromic surveillance were combined to assess the health impacts of wildfire smoke in rural counties with sparse air-quality monitoring. This is the first study to demonstrate both respiratory and cardiac effects after brief exposure to peat wildfire smoke.