Determination of the minimal clinically important difference of the UNC Dry Eye Management Scale

Purpose: To establish an initial estimation of the MCID of the University of North Carolina Dry Eye Management Scale (UNC DEMS) and assess its association with patient perceptions of symptom change. Methods: Thirty-three patients (33.3% men, 67.7% women, mean age 60.5 yrs) with previous DEMS scores were recruited from a UNC ophthalmology clinic in spring 2014. We used anchor-based methods, categorizing important symptom change, to compare the change in the DEMS scores across visits to patient assessments of change; linear regression coefficients estimated the MCID. We correlated clinical assessments, patient perceptions, and DEMS scores. Results: DEMS score changes correlated with global anchors [20.4229 (P = 0.014)]. Unadjusted linear regression yielded a beta coefficient of 20.54 (confidence interval, 20.97 to 20.12, R2 = 0.18, P = 0.014), which estimated the DEMS MCID. Adjusting the regression model for days since the last visit and DEMS score improved the association (beta = 20.56; confidence interval, 20.99 to 20.13; R2 = 0.43; P = 0.013). Descriptive statistics produced an MCID of 1 point. Patients said that 2 points would represent a significant change. The DEMS modestly correlated with the Schirmer test (20.4045, P = 0.0266), Oxford Grading Scheme (+0.3713, P = 0.0364), and tear breakup time (20.3559, P = 0.0456). Conclusions: The UNC DEMS is a valid, responsive patient-reported outcome measure instrument, which is easy to use in the clinic and capable of showing an MCID of 1 point

Influence of sweeping detonation-wave loading on shock hardening and damage evolution during spallation loading in tantalum

Widespread research over the past five decades has provided a wealth of experimental data and insight concerning the shock hardening, damage evolution, and the spallation response of materials subjected to square-topped shock-wave loading profiles. However, fewer quantitative studies have been conducted on the effect of direct, in-contact, high explosive (HE)-driven Taylor wave (unsupported shocks) loading on the shock hardening, damage evolution, or spallation response of materials. Systematic studies quantifying the effect of sweeping-detonation wave loading are yet sparser. In this study, the shock hardening and spallation response of Ta is shown to be critically dependent on the peak shock stress and the shock obliquity during sweeping-detonation-wave shock loading. Sweeping-wave loading is observed to: a) yield a lower spall strength than previously documented for 1-D supported-shock-wave loading, b) exhibit increased shock hardening as a function of increasing obliquity, and c) lead to an increased incidence of deformation twin formation with increasing shock obliquity

LOCAL INDUSTRIAL DEVELOPMENT GROUPS: PERSPECTIVES AND PROFILES

Local industrial development groups (LIDGs) are often among the most visible organizations involved in community economic development. LIDGs annually spend billions of dollars directly or indirectly in various promotional and community improvement efforts. Yet relatively little is known about their organizational forms, their operating strategies, or their real impact on the economic development of communities. The study reported here was undertaken by researchers from three academic backgrounds in order to capture a rich, comprehensive view of this organizational type. In this paper, we discuss the research perspectives which informed our overall approach to the study, and subsequently, we present and discuss a preliminary profile of LIDGs, based on our recent national survey. Copyright 1987 by The Policy Studies Organization.