An architectural understanding of natural sway frequencies in trees.

The relationship between form and function in trees is the subject of a longstanding debate in forest ecology and provides the basis for theories concerning forest ecosystem structure and metabolism. Trees interact with the wind in a dynamic manner and exhibit natural sway frequencies and damping processes that are important in understanding wind damage. Tree-wind dynamics are related to tree architecture, but this relationship is not well understood. We present a comprehensive view of natural sway frequencies in trees by compiling a dataset of field measurement spanning conifers and broadleaves, tropical and temperate forests. The field data show that a cantilever beam approximation adequately predicts the fundamental frequency of conifers, but not that of broadleaf trees. We also use structurally detailed tree dynamics simulations to test fundamental assumptions underpinning models of natural frequencies in trees. We model the dynamic properties of greater than 1000 trees using a finite-element approach based on accurate three-dimensional model trees derived from terrestrial laser scanning data. We show that (1) residual variation, the variation not explained by the cantilever beam approximation, in fundamental frequencies of broadleaf trees is driven by their architecture; (2) slender trees behave like a simple pendulum, with a single natural frequency dominating their motion, which makes them vulnerable to wind damage and (3) the presence of leaves decreases both the fundamental frequency and the damping ratio. These findings demonstrate the value of new three-dimensional measurements for understanding wind impacts on trees and suggest new directions for improving our understanding of tree dynamics from conifer plantations to natural forests.

An increase in minimum metabolic rate and not activity explains field metabolic rate changes in a breeding seabird.

The field metabolic rate (FMR) of a free-ranging animal can be considered as the sum of its maintenance costs (minimum metabolic rate, MMR) and additional costs associated with thermoregulation, digestion, production and activity. However, the relationships between FMR and BMR and how they relate to behaviour and extrinsic influences is not clear. In seabirds, FMR has been shown to increase during the breeding season. This is presumed to be the result of an increase in foraging activity, stimulated by increased food demands from growing chicks, but few studies have investigated in detail the factors that underlie these increases. We studied free-ranging Australasian gannets (Morus serrator) throughout their 5 month breeding season, and evaluated FMR, MMR and activity-related metabolic costs on a daily basis using the heart rate method. In addition, we simultaneously recorded behaviour (flying and diving) in the same individuals. FMR increased steadily throughout the breeding season, increasing by 11% from the incubation period to the long chick-brooding period. However, this was not accompanied by either an increase in flying or diving behaviour, or an increase in the energetic costs of activity. Instead, the changes in FMR could be explained exclusively by a progressive increase in MMR. Seasonal changes in MMR could be due to a change in body composition or a decrease in body condition associated with changing the allocation of resources between provisioning adults and growing chicks. Our study highlights the importance of measuring physiological parameters continuously in free-ranging animals in order to understand fully the mechanisms underpinning seasonal changes in physiology and behaviour.

Opportunistic MMR vaccination for unimmunized children at the time of routine teenage booster vaccination in secondary schools: implications for policy.

With the aim of minimizing adverse health outcomes and reducing the risk of outbreaks, we offered one dose of MMR vaccine to children known to be incompletely immunized at the time of teenage booster vaccination in secondary schools in Swindon in 2011. The Child Health Department database was queried to identify Year 10 children who had had zero or one dose of MMR vaccine previously. Of the 316 children offered vaccination, 60 received a first dose and 87 received a second dose of MMR vaccine. Fourteen children had two documented doses in the past and two had contraindications to the vaccine. Overall uptake of two doses of MMR vaccine increased from 86·3% to 90·6%. The valuable uptake achieved demonstrates that an opportunistic offer of MMR vaccine for unimmunized children at schools is feasible and beneficial. MMR vaccine should be offered routinely to unimmunized children at the time of school vaccination programmes, especially in areas with sub-optimal coverage.

Rapid assessment of clinical information systems in the healthcare setting: an efficient method for time-pressed evaluation.

OBJECTIVE: Recent legislation in the United States provides strong incentives for implementation of electronic health records (EHRs). The ensuing transformation in U.S. health care will increase demand for new methods to evaluate clinical informatics interventions. Timeline constraints and a rapidly changing environment will make traditional evaluation techniques burdensome. This paper describes an anthropological approach that provides a fast and flexible way to evaluate clinical information systems. METHODS: Adapting mixed-method evaluation approaches from anthropology, we describe a rapid assessment process (RAP) for assessing clinical informatics interventions in health care that we developed and used during seven site visits to diverse community hospitals and primary care settings in the U.S. SETTING: Our multidisciplinary team used RAP to evaluate factors that either encouraged people to use clinical decision support (CDS) systems or interfered with use of these systems in settings ranging from large urban hospitals to single-practitioner, private family practices in small towns. RESULTS: Critical elements of the method include: 1) developing a fieldwork guide; 2) carefully selecting observation sites and participants; 3) thoroughly preparing for site visits; 4) partnering with local collaborators; 5) collecting robust data by using multiple researchers and methods; and 6) analyzing and reporting data in a structured manner helpful to the organizations being evaluated. CONCLUSIONS: RAP, iteratively developed over the course of visits to seven clinical sites across the U.S., has succeeded in allowing a multidisciplinary team of informatics researchers to plan, gather and analyze data, and report results in a maximally efficient manner.

The effect of immigration and welfare reform legislation on immigrants' access to health care, Cuyahoga, and Lorain Counties.

This study examined the effect of the passage of the Personal Responsibility and Work Opportunity Reconciliation Act of 1996 and the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 on immigrants' ability to access health care in two counties in Northeastern Ohio. Semistructured interviews were conducted with 251 individuals of varying immigration status and ethnicity. Data collected included type of recent illness, type and location of care received, type of health insurance, if any, and problems encountered. Significant associations were found between birth in a former Soviet-controlled area and use of public insurance. We did not detect an adverse effect of the welfare and immigration reform laws on ability to access care, most likely because a large proportion of respondents were permanent residents or asylees and were eligible for publicly funded medical care under the reform laws. The most common problems in obtaining medical care included lack of insurance and/or money, transportation, language, dissatisfaction with the doctor's care, and long waits. Individuals born in former Soviet-controlled areas as well as those who spoke Spanish or Slavic languages at home or work reported more difficulties in accessing care. Many undocumented individuals indicated that they would delay or refrain from seeking care due to fear of immigration consequences.

The assessment of immigration status in health research.

OBJECTIVE: This report examines methodological issues relating to immigrant health, definition of immigrant, the assessment of immigrant status, and sampling strategies with immigrant populations. METHODS: A literature review was conducted for the period 1977-98, utilizing various computer data bases to identify relevant studies. A total of 179 separate U.S.-based studies were reviewed. Twenty-two sample instruments and two revised versions of instruments for the assessment of immigration status were evaluated. RESULTS: In general, research relating to immigrants and their health has not attended to methodological issues inherent in such investigations. Instruments utilized to assess immigration status differ across studies, making cross-study comparisons difficult. Few studies have relied on probability sampling. Almost no data are available on field performance of instruments developed to assess immigration status. CONCLUSIONS: Development of an appropriate instrument requires consideration of the definition of immigrant to be used, the level of respondent knowledge to be presumed, the political and social climate that exists at the time of the survey administration, the populations and geographic locales with which the instrument will be utilized, the complexity of the instrument, and methods of the instrument administration. In view of the paucity of data pertaining to the field performance of instruments used to assess immigration status, any instrument considered for use must be field tested and revised appropriately before incorporation into a national survey. The appropriateness of any particular sampling strategy should be evaluated in the context of the field testing.

The effect of synthetic polymers on the electrical and permeability properties of lipid membranes.

1. The effect of two series of hydrophilic and hydrophobic polymers on the stability, conductivity and permeability towards water and leucine of black lipid membranes and liposomes is reported. 2. The changes in properties of these membrane preparations is related to bulk phase viscosity and dielectric measurements together with monolayer studies. 3. The hydrophobic polymers dramatically increase membrane stability, had no effect on conductivity, but increased the permeability coefficient of leucine. 4. The hydrophilic polymers produced minor, but significant changes to membrane properties. 5. It is concluded that not only basic polymers but also neutral and acidic macromolecules can interact strongly with lipid membranes.