Preliminary program evaluation of emergency department HIV prevention counseling.
ABSTRACT Controversy surrounds the linkage of prevention counseling with emergency department (ED)-based HIV testing. Further, the effectiveness and feasibility of prevention counseling in the ED setting is unknown. We investigate these issues by conducting a preliminarily exploration of several related aspects of our ED's HIV prevention counseling and testing program.
Our urban, academic ED provides formal client-centered prevention counseling in conjunction with HIV testing. Five descriptive, exploratory observations were conducted, involving surveys and analysis of electronic medical records and programmatic data focused on (1) patient perception and feasibility of prevention counseling in the ED, (2) patient perceptions of the need to link prevention counseling with testing, and (3) potential effectiveness of providing prevention counseling in conjunction with ED-based HIV testing.
Of 110 ED patients surveyed after prevention counseling and testing, 98% believed privacy was adequate, and 97% reported that their questions were answered. Patients stated that counseling would lead to improved health (80%), behavioral changes (72%), follow-up testing (77%), and discussion with partners (74%). However, 89% would accept testing without counseling, 32% were willing to seek counseling elsewhere, and 26% preferred not to receive the counseling. Correct responses to a 16-question knowledge quiz increased by 1.6 after counseling (95% confidence interval 1.3 to 12.0). The program completed counseling for 97% of patients tested; however, 6% of patients had difficulty recalling the encounter and 13% denied received testing. Among patients undergoing repeated testing, there was no consistent change in self-reported risk behaviors.
Participants in the ED prevention counseling and testing program considered counseling acceptable and useful, though not required. Given adequate resources, prevention counseling can be provided in the ED, but it is unlikely that all patients benefit.
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ABSTRACT: Airborne hyperspectral data were analyzed for the classification of 11 forest cover types, including pure and mixed stands of deciduous and conifer species. Selected bands from first difference reflectance spectra were used to determine cover type at the Harvard Forest using a maximum likelihood algorithm assigning all pixels in the image into one of the 11 categories. This approach combines species specific chemical characteristics and previously derived relationships between hyperspectral data and foliar chemistry. Field data utilized for validation of the classification included both a stand-level survey of stem diameter, and field measurements of plot level foliar biomass. A random selection of validation pixels yielded an overall classification accuracy of 75%.Remote Sensing of Environment - REMOTE SENS ENVIRON. 01/1998; 65(3):249-254.
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ABSTRACT: Variation in the foliar chemistry of humid tropical forests is poorly understood, and airborne imaging spectroscopy could provide useful information at leaf and canopy scales. However, variation in canopy structure affects our ability to estimate foliar properties from airborne spectrometer data, yet these structural affects remain poorly quantified. Using leaf spectral (400–2500 nm) and chemical data collected from 162 Australian tropical forest species, along with partial least squares (PLS) analysis and canopy radiative transfer modeling, we determined the strength of the relationship between canopy reflectance and foliar properties under conditions of varying canopy structure.At the leaf level, chlorophylls, carotenoids and specific leaf area (SLA) were highly correlated with leaf spectral reflectance (r = 0.90–0.91). Foliar nutrients and water were also well represented by the leaf spectra (r = 0.79–0.85). When the leaf spectra were incorporated into the canopy radiative transfer simulations with an idealistic leaf area index (LAI) = 5.0, correlations between canopy reflectance spectra and leaf properties increased in strength by 4–18%. The effects of random LAI (= 3.0–6.5) variation on the retrieval of leaf properties remained minimal, particularly for pigments and SLA (r = 0.92–0.93). In contrast, correlations between leaf nitrogen (N) and canopy reflectance estimates decreased from r = 0.87 at constant LAI = 5 to r = 0.65 with randomly varying LAI = 3.0–6.5. Progressive increases in the structural variability among simulated tree crowns had relatively little effect on pigment, SLA and water predictions. However, N and phosphorus (P) were more sensitive to canopy structural variability. Our modeling results suggest that multiple leaf chemicals and SLA can be estimated from leaf and canopy reflectance spectroscopy, and that the high-LAI canopies found in tropical forests enhance the signal via multiple scattering. Finally, the two factors we found to most negatively impact leaf chemical predictions from canopy reflectance were variation in LAI and viewing geometry, which can be managed with new airborne technologies and analytical methods.Remote Sensing of Environment. 01/2008;
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ABSTRACT: The potentials and limits of estimating canopy parameters are investigated using only a reflectance spectrum in the optical domain, and the PROSPECT + SAIL model. Simulations are performed on AVIRIS (Airborne Visible / Infrared Imaging Spectrometer) equivalent spectra, corrected for the atmospheric effects. It is established that this model is numerically invertible. The sensitivity analysis of reflectance spectral features to changes in the values of canopy parameters (leaf mesophyll structure N, chlorophyll a + b concentration Cab, water depth Cw, leaf area index, LAI, and average leaf inclination angle θ1) suggests that the accuracy of the inversion procedure needs some constraints. The Cab and Cw parameters, which describe the leaf physiological status, can be generally retrieved with a reasonable accuracy; it is somewhat difficult to estimate the canopy geometrical parameters (LAI and θ1) separately. Determining the fraction of absorbed photosynthetic active radiation (APAR) with parameters derived from the inversion procedure is discussed.Remote Sensing of Environment - REMOTE SENS ENVIRON. 01/1993; 44:281-292.