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Ward, Matthew J.

Publications and source records attributed to Ward, Matthew J..

A proposed framework for the development and qualitative evaluation of West Nile virus models and their application to local public health decision-making

West Nile virus (WNV) is a globally distributed mosquito-borne virus of great public health concern. The number of WNV human cases and mosquito infection patterns vary in space and time. Many statistical models have been developed to understand and predict WNV geographic and temporal dynamics. However, these modeling efforts have been disjointed with little model comparison and inconsistent validation. In this paper, we describe a framework to unify and standardize WNV modeling efforts nationwide. WNV risk, detection, or warning models for this review were solicited from active research groups working in different regions of the United States. A total of 13 models were selected and described. The spatial and temporal scales of each model were compared to guide the timing and the locations for mosquito and virus surveillance, to support mosquito vector control decisions, and to assist in conducting public health outreach campaigns at multiple scales of decision-making. Our overarching goal is to bridge the existing gap between model development, which is usually conducted as an academic exercise, and practical model applications, which occur at state, tribal, local, or territorial public health and mosquito control agency levels. The proposed model assessment and comparison framework helps clarify the value of individual models for decision-making and identifies the appropriate temporal and spatial scope of each model. This qualitative evaluation clearly identifies gaps in linking models to applied decisions and sets the stage for a quantitative comparison of models. Specifically, whereas many coarse-grained models (county resolution or greater) have been developed, the greatest need is for fine-grained, short-term planning models (m–km, days–weeks) that remain scarce. We further recommend quantifying the value of information for each decision to identify decisions that would benefit most from model input.

60 APPLIED LIFE SCIENCES↗

X-ray emission spectroscopy: an effective route to extract site occupation of cations

Cation site occupation is an important determinant of materials properties, especially in a complex system with multiple cations such as in ternary spinels. In this work, we show that XES provides not only the site occupation information as EXAFS, but also additional information on the oxidation states of the cations at each site. Additionally, we show that XES is a superior and a far more accurate method than EXAFS.

Bhargava, Anuj↗

Epitaxial crystals of Bi{sub 2}Pt{sub 2}O{sub 7} pyrochlore through the transformation of δ–Bi{sub 2}O{sub 3} fluorite

Bi{sub 2}Pt{sub 2}O{sub 7} pyrochlore is thought to be one of the most promising oxide catalysts for application in fuel cell technology. Unfortunately, direct film growth of Bi{sub 2}Pt{sub 2}O{sub 7} has not yet been achieved, owing to the difficulty of oxidizing platinum metal in the precursor material to Pt{sup 4+}. In this work, in order to induce oxidation of the platinum, we annealed pulsed laser deposited films consisting of epitaxial δ–Bi{sub 2}O{sub 3} and co-deposited, comparatively disordered platinum. We present synchrotron x-ray diffraction results that show the nonuniform annealed films contain the first epitaxial crystals of Bi{sub 2}Pt{sub 2}O{sub 7}. We also visualized the pyrochlore structure by scanning transmission electron microscopy, and observed ordered cation vacancies in the epitaxial crystals formed in a bismuth-rich film but not in those formed in a platinum-rich film. The similarity between the δ–Bi{sub 2}O{sub 3} and Bi{sub 2}Pt{sub 2}O{sub 7} structures appears to facilitate the pyrochlore formation. These results provide the only route to date for the formation of epitaxial Bi{sub 2}Pt{sub 2}O{sub 7}.

36 MATERIALS SCIENCE↗