The effect of signal noise on the remote sensing of Foliar biochemical concentration

Spectral measurements made using an imaging spectrometer contain systematic and random noise, while the former can be corrected the latter remains a source of error in the remotely sensed signal. A number of investigators have tried to determine the signal-to-noise-ratio (SNR) of the instrument, or the resultant imagery. However, the level of noise at which spectra are too noisy to be useful is not usually determined. The first attempt was by Goetz and Calvin, who suggested that the depth of the absorption feature should be at least an order of magnitude greater than the noise and more recently Dekker suggested a SNR of around 600:1 was required in visible/near infrared wavelengths to measure a 1/gl change in chlorophyll a concentration water. The wide range of applications of imaging spectroscopy make it difficult to set SNR specifications as they are dependent on a number of factors, one of the most important being reflectance of a particular target. For example, the SNR of imagery for vegetated targets is relatively low simply because vegetation has a relatively low level of reflectance. The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is being used to estimate the concentration of biochemicals within vegetation canopies. This paper reports a study undertaken to identify first, wavebands that were highly correlated with foliar biochemical concentration and second, to determine how sensitive these correlations were to sensor noise

Exploring the remote sensing of foliar biochemical concentrations with AVIRIS data

Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data shows promise for the estimation of foliar biochemical concentrations at the scale of the canopy. There are, however, several problems associated with the use of AVIRIS data in this way and these are detailed in recent Plant Biochemical Workshop Report. The research reported was concentrated upon three of these problems: field sampling of forest canopies, wet laboratory assay of foliar chemicals, and the visualization of AVIRIS data

AVIRIS spectra correlated with the chlorophyll concentration of a forest canopy

Imaging spectrometers have many potential applications in the environmental sciences. One of the more promising applications is that of estimating the biochemical concentrations of key foliar biochemicals in forest canopies. These estimates are based on spectroscopic theory developed in agriculture and could be used to provide the spatial inputs necessary for the modeling of forest ecosystem dynamics and productivity. Several foliar biochemicals are currently under investigation ranging from those with primary absorption features in visible to middle infrared wavelengths (e.g., water, chlorophyll) to those with secondary to tertiary absorption features in this part of the spectrum (e.g., nitrogen, lignin). The foliar chemical of interest in this paper is chlorophyll; this is a photoreceptor and catalyst for the conversion of sunlight into chemical energy and as such plays a vital role in the photochemical synthesis of carbohydrates in plants. The aim of the research reported here was to determine if the chlorophyll concentration of a forest canopy could be correlated with the reflectance spectra recorded by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

Acceptability of HIV Testing Sites Among Rural and Urban African Americans Who Use Cocaine

African Americans (AAs) who use cocaine in the Southern region of the U.S. have a relatively high risk of HIV and need for HIV testing. Among this group, those residing in rural areas may have less favorable opinions about common HIV testing sites, which could inhibit HIV testing. We examined rural/urban variations in their acceptability of multiple HIV testing sites (private physician clinic, local health department, community health center, community HIV fair, hospital emergency department, blood plasma donation center, drug abuse treatment facility, and mobile van or community outreach worker). Results from partial proportional odds and logistic regression analyses indicate that rural AA who use cocaine have lower odds of viewing local health departments (OR = 0.09, 95 % CI = 0.03–0.21), physician offices (OR = 0.19, 95 % CI = 0.09–0.42), and drug use treatment centers (OR = 0.49; 95 % CI = 0.30–0.80) as acceptable relative to their urban counterparts. The findings have implications for further targeting HIV testing toward AAs who use of cocaine, particularly those residing in the rural South

Applying hybrid effectiveness-implementation studies in equity-centered policy implementation science

Policy implementation science (IS) is complex, dynamic, and fraught with unique study challenges that set it apart from biomedical or clinical research. One important consideration is the ways in which policy interacts with local contexts, such as power and social disadvantage (e.g., based on ability, race, class, sexual identity, geography). The complex nature of policy IS and the need for more intentional integration of equity principles into study approaches calls for creative adaptations to existing implementation science knowledge and guidance. Effectiveness-implementation hybrid studies were developed to enhance translation of clinical research by addressing research questions around the effectiveness of an intervention and its implementation in the same study. The original work on hybrid designs mainly focused on clinical experimental trials; however, over the last decade, researchers have applied it to a wide range of initiatives and contexts, including more widespread application in community-based studies. This perspectives article demonstrates how effectiveness-implementation hybrid studies can be adapted for and applied to equity-centered policy IS research. We draw upon principles of targeted universalism and Equity in Implementation Research frameworks to guide adaptations to hybrid study typologies, and suggest research and engagement activities to enhance equity considerations; for example, in the design and testing of implementing strategies. We also provide examples of equity-centered policy IS studies. As the field of policy IS rapidly evolves, these adapted hybrid type studies are offered to researchers as a starting guide

Beliefs and attitudes regarding drug treatment: Application of the Theory of Planned Behavior in African-American cocaine users

The Theory of Planned Behavior (TPB) can provide insights into perceived need for cocaine treatment among African American cocaine users

An evaluation of the spread and scale of PatientToc™ from primary care to community pharmacy practice for the collection of patient-reported outcomes: A study protocol

Background Medication non-adherence is a problem of critical importance, affecting approximately 50% of all persons taking at least one regularly scheduled prescription medication and costing the United States more than $100 billion annually. Traditional data sources for identifying and resolving medication non-adherence in community pharmacies include prescription fill histories. However, medication possession does not necessarily mean patients are taking their medications as prescribed. Patient-reported outcomes (PROs), measuring adherence challenges pertaining to both remembering and intention to take medication, offer a rich data source for pharmacists and prescribers to use to resolve medication non-adherence. PatientToc™ is a PROs collection software developed to facilitate collection of PROs data from low-literacy and non-English speaking patients in Los Angeles. Objectives This study will evaluate the spread and scale of PatientToc™ from primary care to community pharmacies for the collection and use of PROs data pertaining to medication adherence. Methods The following implementation and evaluation steps will be conducted: 1) a pre-implementation developmental formative evaluation to determine community pharmacy workflow and current practices for identifying and resolving medication non-adherence, potential barriers and facilitators to PatientToc™ implementation, and to create a draft implementation toolkit, 2) two plan-do-study-act cycles to refine an implementation toolkit for spreading and scaling implementation of PatientToc™ in community pharmacies, and 3) a comprehensive, theory-driven evaluation of the quality of care, implementation, and patient health outcomes of spreading and scaling PatientToc™ to community pharmacies. Expected impact This research will inform long-term collection and use of PROs data pertaining to medication adherence in community pharmacies

Preparing for the spread of patient-reported outcomes (PROs) data collection from primary care to community pharmacy: stakeholder insights

Medication non-adherence is a significant public health problem. Patient-reported outcomes (PROs) offer a rich data source to facilitate resolution of medication non-adherence. PatientToc™ is an electronic PRO data collection software originally implemented at primary care practices in California, United States (US). Currently, the use of standardized PRO data collection systems in US community pharmacies is limited. Thus, we are conducting a two-phase evaluation of the spread and scale of PatientToc™ to US Midwestern community pharmacies. This report focuses on the first phase of the evaluation. The objective of this phase was to prepare for implementation of PatientToc™ in community pharmacies by conducting a pre-implementation developmental formative evaluation to (1) identify potential barriers, facilitators, and actionable recommendations to PatientToc™ implementation and (2) create a draft implementation toolkit

An Overview of Research and Evaluation Designs for Dissemination and Implementation

The wide variety of dissemination and implementation designs now being used to evaluate and improve health systems and outcomes warrants review of the scope, features, and limitations of these designs

VAST: An ASKAP Survey for Variables and Slow Transients

The Australian Square Kilometre Array Pathfinder (ASKAP) will give us an unprecedented opportunity to investigate the transient sky at radio wavelengths. In this paper we present VAST, an ASKAP survey for Variables and Slow Transients. VAST will exploit the wide-field survey capabilities of ASKAP to enable the discovery and investigation of variable and transient phenomena from the local to the cosmological, including flare stars, intermittent pulsars, X-ray binaries, magnetars, extreme scattering events, interstellar scintillation, radio supernovae and orphan afterglows of gamma ray bursts. In addition, it will allow us to probe unexplored regions of parameter space where new classes of transient sources may be detected. In this paper we review the known radio transient and variable populations and the current results from blind radio surveys. We outline a comprehensive program based on a multi-tiered survey strategy to characterise the radio transient sky through detection and monitoring of transient and variable sources on the ASKAP imaging timescales of five seconds and greater. We also present an analysis of the expected source populations that we will be able to detect with VAST.Comment: 29 pages, 8 figures. Submitted for publication in Pub. Astron. Soc. Australi