Total internal reflection Raman spectroscopy

Total internal reflection (TIR) Raman spectroscopy is an experimentally straightforward, surface-sensitive technique for obtaining chemically specific spectroscopic information from a region within approximately 100–200 nm of a surface. While TIR Raman spectroscopy has long been overshadowed by surface-enhanced Raman scattering, with modern instrumentation TIR Raman spectra can be acquired from sub-nm thick films in only a few seconds. In this review, we describe the physical basis of TIR Raman spectroscopy and illustrate the performance of the technique in the diverse fields of surfactant adsorption, liquid crystals, lubrication, polymer films and biological interfaces, including both macroscopic structures such as the surfaces of leaves, and microscopic structures such as lipid bilayers. Progress, and challenges, in using TIR Raman to obtain depth profiles with sub-diffraction resolution are described

Finding qualitative research: an evaluation of search strategies

BACKGROUND: Qualitative research makes an important contribution to our understanding of health and healthcare. However, qualitative evidence can be difficult to search for and identify, and the effectiveness of different types of search strategies is unknown. METHODS: Three search strategies for qualitative research in the example area of support for breast-feeding were evaluated using six electronic bibliographic databases. The strategies were based on using thesaurus terms, free-text terms and broad-based terms. These strategies were combined with recognised search terms for support for breast-feeding previously used in a Cochrane review. For each strategy, we evaluated the recall (potentially relevant records found) and precision (actually relevant records found). RESULTS: A total yield of 7420 potentially relevant records was retrieved by the three strategies combined. Of these, 262 were judged relevant. Using one strategy alone would miss relevant records. The broad-based strategy had the highest recall and the thesaurus strategy the highest precision. Precision was generally poor: 96% of records initially identified as potentially relevant were deemed irrelevant. Searching for qualitative research involves trade-offs between recall and precision. CONCLUSIONS: These findings confirm that strategies that attempt to maximise the number of potentially relevant records found are likely to result in a large number of false positives. The findings also suggest that a range of search terms is required to optimise searching for qualitative evidence. This underlines the problems of current methods for indexing qualitative research in bibliographic databases and indicates where improvements need to be made

A MARKETING-SYSTEM APPROACH TO REMOVING DISTRIBUTION BARRIERS CONFRONTING SMALL-VOLUME FRUIT AND VEGETABLE GROWERS

Marketing,

‘Arm-based’ parameterization for network meta-analysis

We present an alternative to the contrast‐based parameterization used in a number of publications for network meta‐analysis. This alternative “arm‐based” parameterization offers a number of advantages: it allows for a “long” normalized data structure that remains constant regardless of the number of comparators; it can be used to directly incorporate individual patient data into the analysis; the incorporation of multi‐arm trials is straightforward and avoids the need to generate a multivariate distribution describing treatment effects; there is a direct mapping between the parameterization and the analysis script in languages such as WinBUGS and finally, the arm‐based parameterization allows simple extension to treatment‐specific random treatment effect variances. We validated the parameterization using a published smoking cessation dataset. Network meta‐analysis using arm‐ and contrast‐based parameterizations produced comparable results (with means and standard deviations being within +/− 0.01) for both fixed and random effects models. We recommend that analysts consider using arm‐based parameterization when carrying out network meta‐analyses

Surfactant adsorption by total internal reflection Raman spectroscopy. Part III: Adsorption onto cellulose

TIR Raman spectroscopy has been used to study the adsorption of surfactants onto cellulose. The cellulose was prepared by Langmuir–Blodgett deposition of trimethylsilylcellulose onto silica followed by removal of the trimethylsilyl groups with acid to generate a hydrophilic surface. The reaction was followed in situ with Raman spectroscopy, revealing a two-step hydrolysis. Adsorption isotherms of hexadecyltrimethylammonium bromide (CTAB) and Triton X-100 (TX-100) on hydrophilic cellulose were obtained by TIR Raman scattering under quasi-equilibrium conditions where the bulk concentration was slowly but continuously varied. The isotherms of both surfactants are almost linear, in contrast to the isotherms on hydrophilic silica. The CTAB isotherm shows hysteresis depending on whether the concentration of the surfactant is increasing or decreasing due to a slow adsorption region. A mixture of TX-100 and CTAB shows ideal adsorption, in contrast to adsorption of the same mixture on silica where there is a strong cooperative interaction at low CTAB surface coverage

PUBLIC MARKETS AND THE DEVELOPMENT OF THE FRESH-PRODUCE INDUSTRY

Agribusiness,

Point-Mass Aircraft Trajectory Prediction Using a Hierarchical, Highly-Adaptable Software Design

A highly adaptable and extensible method for predicting four-dimensional trajectories of civil aircraft has been developed. This method, Behavior-Based Trajectory Prediction, is based on taxonomic concepts developed for the description and comparison of trajectory prediction software. A hierarchical approach to the "behavioral" layer of a point-mass model of aircraft flight, a clear separation between the "behavioral" and "mathematical" layers of the model, and an abstraction of the methods of integrating differential equations in the "mathematical" layer have been demonstrated to support aircraft models of different types (in particular, turbojet vs. turboprop aircraft) using performance models at different levels of detail and in different formats, and promise to be easily extensible to other aircraft types and sources of data. The resulting trajectories predict location, altitude, lateral and vertical speeds, and fuel consumption along the flight path of the subject aircraft accurately and quickly, accounting for local conditions of wind and outside air temperature. The Behavior-Based Trajectory Prediction concept was implemented in NASA's Traffic Aware Planner (TAP) flight-optimizing cockpit software application

A national survey of New Zealand registered nurses caring attributes, professional self concept and technological influences

School of Nursin

State Department of Agriculture Participation in Fresh Produce Marketing in Georgia, Kentucky, North Carolina, and Tennessee

Agricultural and Food Policy,

Removing Distribution Barriers Confronting Small-Volume Fruit and Vegetable Growers: Results of the Tennessee Extension Service Survey

Crop Production/Industries, Teaching/Communication/Extension/Profession,