Biomedical subjects

Richard A Davis

Publications and source records attributed to Richard A Davis.

4 recordsLinked to original sources

PubMed2006

Model selection for geostatistical models.

We consider the problem of model selection for geospatial data. Spatial correlation is often ignored in the selection of explanatory variables, and this can influence model selection results. For example, the importance of particular explanatory variables may not be apparent when spatial correlation is ignored. To address this problem, we consider the Akaike Information Criterion (AIC) as applied to a geostatistical model. We offer a heuristic derivation of the AIC in this context and provide simulation results that show that using AIC for a geostatistical model is superior to the often-used traditional approach of ignoring spatial correlation in the selection of explanatory variables. These ideas are further demonstrated via a model for lizard abundance. We also apply the principle of minimum description length (MDL) to variable selection for the geostatistical model. The effect of sampling design on the selection of explanatory covariates is also explored. R software to implement the geostatistical model selection methods described in this paper is available in the Supplement.

Animals↗

PubMed2005

Technique to facilitate graft passage in posterolateral reconstructions of the knee.

This report describes a novel technique to facilitate passage of the transtibial limb of grafts used for reconstruction of the posterolateral corner of the knee. This new method, which places and passes the graft within a 24F (8-mm) chest tube, eliminates the problem of graft impingement at the opening of the posterior tibial tunnel and the need to enlarge the tunnel to achieve graft passage. Enlarging the tunnel is detrimental to obtaining the snug fit that is necessary to maximize incorporation of the graft and minimize postoperative tunnel expansion. This chest tube technique, which has been used in 20 cases to date, makes graft passage expeditious and requires no special instrumentation.

Achilles Tendon↗

PubMed2002

Validation of a new scale for measuring problematic internet use: implications for pre-employment screening.

The current study introduced a theory-driven, multidimensional measure of problematic Internet use: the Online Cognition Scale (OCS). Undergraduate students (n = 211) in an industrial/organizational psychology course completed the OCS, along with measures of procrastination, rejection sensitivity, loneliness, depression, and impulsivity. A confirmatory factor analysis indicated that problematic Internet use consists of four dimensions: diminished impulse control, loneliness/depression, social comfort, and distraction. As hypothesized, the OCS predicted all of the study variables in the expected directions. Representing a departure from previous research in this area, the current article focused on procrastination, impulsivity, and social rejection as key elements of problematic Internet use. Furthermore, interactive applications (e.g., chat) were most related to problematic Internet use, and scores on the OCS predicted being reprimanded at school or work for inappropriate Internet use. As a result, the utility of the OCS for both clinical assessment of Internet addiction and as an organizational preemployment screening measure to identify potential employees who are likely to abuse the Internet in the workplace (also known as "cyberslacking") were discussed.

Adult↗

PubMed2002

Lost in cyberspace: the web @ work.

Most U.S. businesses provide Internet access for their employees. The current study surveyed representatives from 224 organizations on issues related to Internet abuse. Nearly 70% of companies surveyed had more than half of their employees online. Almost all companies had Internet access policies (IAP) in place (82.6%), outlining appropriate and inappropriate use of the Internet in the workplace. Despite IAPs, U.S. businesses are facing a severe problem. More than 60% of companies had disciplined-and more than 30% had terminated--employees for inappropriate use of the Internet. Accessing pornography, online chatting, gaming, investing, or shopping at work were the leading causes for disciplinary action or termination. Many companies were not concerned about the severity of the problem (49.6%) and/or had done very little to enforce their IAPs (59.4% use self or managerial oversight, and only 37.5% use filtering software).

Behavior, Addictive↗