Valerie A. Thomas

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The aim of this study was to determine the metabolic changes in the transition from pre-invasive to invasive cervical cancer using high-resolution magic angle spinning (HR-MAS) MRS. Biopsy specimens were obtained from women with histologically normal cervix (n = 5), cervical intraepithelial neoplasia (CIN; mild, n = 5; moderate/severe, n = 40), and invasive(More)
Hyperplasia of usual type (HUT) is part of the spectrum of benign proliferative disease in the breast and confers an increased risk of developing invasive cancer. Its role as a putative precursor of invasive ductal carcinomas in the breast is, however, controversial. HUT is occasionally seen bilaterally but it is not clear whether there is a genetic(More)
With the advent of free Landsat data stretching back decades, there has been a surge of interest in utilizing remotely sensed data in multitemporal analysis for estimation of biophysical parameters. Such analysis is confounded by cloud cover and other image-specific problems, which result in missing data at various aperiodic times of the year. While there(More)
Successful conservation and management of wetlands requires up-to-date and accurate information on wetland location, size, condition, functionality, type, services provided, stressors and net change in extent. Most change detection studies utilize two date images to provide information on wetland dynamics. Comparison of infrequent imagery might not(More)
OBJECTIVE To determine whether the conventional large loop excision of the transformation zone (CLLETZ) and the "top-hat" technique (THLLETZ) differ in (a) completeness of excision of the cervical lesion, (b) depth of cervical tissue excised and (c) adequacy of follow up by cytology and colposcopy. DESIGN Retrospective case review. SETTING University(More)
One challenge to implementing spectral change detection algorithms using multitemporal Landsat data is that key dates and periods are often missing from the record due to weather disturbances and lapses in continuous coverage. This paper presents a method that utilizes residuals from harmonic regression over years of Landsat data, in conjunction with(More)
The objective of this study was to determine whether leaf area index (LAI) in temperate mixed forests is best estimated using multiple-return airborne laser scanning (lidar) data or dual-band, single-pass interferometric synthetic aperture radar data (from GeoSAR) alone, or both in combination. In situ measurements of LAI were made using the LiCor LAI-2000(More)
The need for an efficient and standard technique for optimal spectral sampling of hyperspectral data during the inversion of canopy reflectance models has been the subject of many studies. The objective of this study was to investigate the utility of the discrete wavelet transform (DWT) for extracting useful features from hyperspectral data with which(More)
There are pressing concerns about the interplay between agricultural productivity, water demand, and water availability in semi-arid to arid regions of the world. Currently, irrigated agriculture is the dominant water user in these regions and is estimated to consume approximately 80% of the world’s diverted freshwater resources. We develop an improved(More)
Reliable global estimates of forest biomass and its dynamics are critically important for understanding the global carbon cycle and its dynamics (e.g., Bellassen et al. 2011). Many studies have been published regarding the estimation of above-ground biomass using airborne or satellite analog lidar systems (e.g., Nelson et al. 1988; Naesset 2002; Drake et(More)