Quantification of Pulmonary Arterial Wall Distensibility Using Parameters Extracted from Volumetric Micro-CT Images

Stiffening, or loss of distensibility, of arterial vessel walls is among the manifestations of a number of vascular diseases including pulmonary arterial hypertension. We are attempting to quantify the mechanical properties of vessel walls of the pulmonary arterial tree using parameters derived from high-resolution volumetric x-ray CT images of rat lungs. The pulmonary arterial trees of the excised lungs are filled with a contrast agent. The lungs are imaged with arterial pressures spanning the physiological range. Vessel segment diameters are measured from the inlet to the periphery, and distensibilities calculated from diameters as a function of pressure. The method shows promise as an adjunct to other morphometric techniques such as histology and corrosion casting. It possesses the advantages of being nondestructive, characterizing the vascular structures while the lungs are imaged rapidly and in a near-physiological state, and providing the ability to associate mechanical properties with vessel location in the intact tree hierarchy

Seasonal Variation in Diet of a Marginal Population of the Hispid Cotton Rat, Sigmodon hispidus

Cotton rats live in oldfields, habitats with a variety of mostly herbaceous plants. Based on other studies, the hispid cotton rat, Sigmodon hispidus, eats many kinds of herbaceous plants but grasses predominate. In contrast, our population of cotton rats ate many monocots but mostly they were not grasses. Our study sought to determine the diet of the cotton rat in eastern Virginia, near the northern limit of distribution on the Atlantic Coast. Fecal samples, collected each month during an on-going capture-mark-release demographic study of the rodent community, were analyzed using a standard method. A greater variety of foods (including insects) was eaten in the summer and autumn than in winter and spring. In winter, when much herbaceous vegetation is standing dead, cotton rats supplemented their diets with pine bark. Cotton rats ate significantly greater proportions of monocots in winter and spring, an apparent response to the need for more calories to compensate for greater heat loss. In summer and autumn, cotton rats enhanced their diets with significantly greater proportions of the more nutritious but harder to digest dicots. Reproductive females ate significantly more dicots and less monocots than males and non-reproductive females, whose diets were similar

Examining the Decline in Bargaining Power in Faculty Labor Unions in the United States: The Effects of Reduced Monopoly Power in Providing Public Higher Education

This study examines the decline in the economic power of faculty labor unions in public higher education in the United States in recent years. The authors assume the labor union is a utility maximizing entity and that income accrues to the “union family.” The union family attempts to maximize this income. By analyzing collective bargaining agreements and hiring practices between the Association of Pennsylvania State College and University Faculties and the Pennsylvania State System of Higher Education, the authors construct bargaining indices. Because this study is focused on the change in bargaining power of labor unions in public higher education over time, each index is constructed by looking at the ratio of the union annual income pay scale from the collective bargaining agreements of the mid-tier public universities in Pennsylvania to the average yearly income for workers in the private nonagricultural industries. Borrowing from the Harris-Todaro labor migration model, we construct a composite bargaining index where the original bargaining index is discounted by incorporating the proportion of part-time temporary faculty permitted by the collective bargaining agreements at the mid-tier public universities in Pennsylvania from 1972 to 2009. By considering the reduced employment of full-time tenured-tenure track faculty that can result from increased wages and salaries, or the increase in employment that may result from decreased wages and salaries, this composite bargaining index gives a better measure of the benefits accruing to the “union family” as faculty incomes are increasing or decreasing than would be given by our “original bargaining index.” Beginning with the early 1970s, and continuing until 2009, we find that the bargaining index has essentially flattened over the past ten years, and the composite bargaining index decreased from 1995 to 2009. Applying an historical perspective approach, the authors conclude that this decline in bargaining power in recent years came from the same sources as the declines in bargaining power in the private sector earlier. Namely, a reduction in monopoly power in the good or service offered to the buyer, substitution in the labor market, and a reduction in regulation of the product market

CONTINGENT VALUATION FOCUS GROUPS: INSIGHTS FROM ETHNOGRAPHIC INTERVIEW TECHNIQUES

Despite the many important uses (and potential abuses) of focus groups in survey design, the CV literature presents few guidelines to aid moderators in their interaction with focus group participants. This paper draws on the theory and practice of ethnographic interviewing to introduce general guidelines that can improve focus groups as an aid to CV research. The proposed guidelines illustrate types of questions that should reduce speculation and moderator-introduced bias in focus group responses, and improve the correspondence between focus group responses and actual behavior. The paper illustrates these ethnographic guidelines through a CV application concerning watershed resources.Research Methods/ Statistical Methods,

Wrack Lines Volume 21, Number 1, Born Out of Crises: responses, research and reflections on a better future

Articles in this issue explore various actions taken in response to different crises: lessons about the environment from the COVID-19 pandemic; how seafood sellers in the CT and Southeast Asia responded to the challenges of the pandemic; how the challenges of rising seas and developed coasts are being dealt with through managed retreat, buyouts and other actions in NC and CT; and research on the long-term effects of the Deepwater Horizon oil spill on dolphins led by CTSG Director Sylvain De Guise

Randomised, double-blind, placebo-controlled trials of non-individualised homeopathic treatment: systematic review and meta-analysis

Background: A rigorous systematic review and meta-analysis focused on randomised controlled trials (RCTs) of non-individualised homeopathic treatment has not previously been reported. We tested the null hypothesis that the main outcome of treatment using a non-individualised (standardised) homeopathic medicine is indistinguishable from that of placebo. An additional aim was to quantify any condition-specific effects of non-individualised homeopathic treatment. Methods: Literature search strategy, data extraction and statistical analysis all followed the methods described in a pre-published protocol. A trial comprised ‘reliable evidence’ if its risk of bias was low or it was unclear in one specified domain of assessment. ‘Effect size’ was reported as standardised mean difference (SMD), with arithmetic transformation for dichotomous data carried out as required; a negative SMD indicated an effect favouring homeopathy. Results: Forty-eight different clinical conditions were represented in 75 eligible RCTs. Forty-nine trials were classed as ‘high risk of bias’ and 23 as ‘uncertain risk of bias’; the remaining three, clinically heterogeneous, trials displayed sufficiently low risk of bias to be designated reliable evidence. Fifty-four trials had extractable data: pooled SMD was –0.33 (95% confidence interval (CI) –0.44, –0.21), which was attenuated to –0.16 (95% CI –0.31, –0.02) after adjustment for publication bias. The three trials with reliable evidence yielded a non-significant pooled SMD: –0.18 (95% CI –0.46, 0.09). There was no single clinical condition for which meta-analysis included reliable evidence. Conclusions: The quality of the body of evidence is low. A meta-analysis of all extractable data leads to rejection of our null hypothesis, but analysis of a small sub-group of reliable evidence does not support that rejection. Reliable evidence is lacking in condition-specific meta-analyses, precluding relevant conclusions. Better designed and more rigorous RCTs are needed in order to develop an evidence base that can decisively provide reliable effect estimates of non-individualised homeopathic treatment