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Biomedical subjects

Richard Levins

Publications and source records attributed to Richard Levins.

8 recordsLinked to original sources
PubMed2006

Adult male height in an American colony: Puerto Rico and the USA mainland compared, 1886-1955.

The links between adult height and socioeconomic-political marginality are controversial. We test hypotheses by comparing secular trends between two groups of USA adult male citizens born during 1886-1930: (a) 9805 men surveyed in Puerto Rico during 1965 and (b) 3064 non-Hispanic Whites surveyed on the mainland during 1971-1975. Puerto Rico provides an apt case study because it is the oldest colony in the world and was the poorest region of the USA during the 20th century. During the period considered the average adult man in Puerto Rico was 164.8 cm tall, 8.3 cm shorter than the average adult man on the mainland (173.1cm). Both groups experienced secular improvements in height, with men on the mainland having higher rates than men in Puerto Rico. In neither case were results statistically significant. The modest changes in Puerto Rico likely reflect the offsetting role of improved health and a stagnant rural economy during the first half of the 20th century.

Body Height↗
PubMed2006

Community-based rice ecosystem management for suppressing vector anophelines in Sri Lanka.

Sri Lanka is one of the Asian countries most affected by mosquito-borne diseases, especially malaria. This 18-month study assessed the effectiveness of a new community-based ecosystem management programme to control mosquito vectors in the country's rice ecosystem. Farmers in a malaria-prone village were educated and motivated to engage in source reduction as well as measures to restore and maximise rice ecosystem functions. Over the course of the programme, the impact of farmers' ecosystem management on local mosquito ecology was also examined. Although little impact was detected on Culex and Aedes densities, adult Anopheles density was significantly suppressed in the southwest monsoon season. Rice farmers who manage their ecosystems can reduce the burden of Anopheles mosquitoes, interrupt malaria transmission and prevent the destruction of ecosystems.

Adolescent↗
PubMed2006

Impact of education on knowledge, agricultural practices, and community actions for mosquito control and mosquito-borne disease prevention in rice ecosystems in Sri Lanka.

Mosquito-borne diseases are a major public health threat in Sri Lanka. A 20-week pilot education program to improve community knowledge and mosquito control with participatory and non-chemical approaches was developed, implemented, and evaluated using pre-educational and post-educational surveys in two intervention and two comparison villages. Correlates of baseline knowledge were sex, number of family members, ratio of family members with malaria history, school education level, and availability of electricity at the residence. Participation in the educational program led to improved knowledge of mosquito ecology and disease epidemiology, changes in agricultural practices, and an increase in environmentally sound measures for mosquito control and disease prevention. The variety of actions at the post-educational stage were determined by improved knowledge, but not by sociodemographic characteristics. Such community-based educational interventions are effective in increasing understanding and active involvement in mosquito control and disease prevention in rice ecosystems regardless of sociodemographic characteristics.

Adult↗
PubMed2005

Life expectancy change in perturbed communities: derivation and qualitative analysis.

Pollution, loss of habitat, and climate change are introducing dramatic perturbations to natural communities and affecting public health. Populations in perturbed communities can change dynamically, in both abundance and age structure. While analysis of the community matrix can predict changes in population abundance arising from a sustained or press perturbation, perturbations also have the potential to modify life expectancy, which adds yet another means to falsify experimental hypotheses and to monitor management interventions in natural systems. In some instances, an input to a community will produce no change in the abundance of a population but create a major shift in its mean age. We present an analysis of change in both abundance and life expectancy, leading to a formal quantitative assessment as well as qualitative predictions, and illustrate the usefulness of the technique through general examples relating to vector-borne disease and fisheries.

Animals↗
PubMed2003

Whose scientific method? Scientific methods for a complex world.

Critics of the precautionary principle assail it for calling for action before science establishes unquestionably that a substance causes harm. They claim theirs is the viewpoint of the "scientific method." But the conflict is not between science and antiscience but rather between different pathways for science and technology; between a commodified science-for-profit and a gentle science for humane goals; between the sciences of the smallest parts and the sciences of dynamic wholes. This article addresses the social construction of scientific production and the pattern of strengths and weaknesses to which it leads. The author offers proposals for a more holistic, integral approach to understanding and addressing environmental issues.

Journal Article↗
PubMed2002

Qualitative analysis of the all-cause black-white mortality crossover.

To date, despite decades of investigations and the relative abundance of mortality data, our understanding of the phenomenon of 'mortality crossover' remains inadequate. We propose a methodology for transforming mortality data from the 'age-domain' to the 'time-domain'. We then introduce a model of selection partially offset by mobility, to simulate the dynamics of vulnerability in a population cohort that is heterogeneous in health and death. Using our model of vulnerability simulating the dynamics of mortality in the time-domain, we compare the mortality experience of the Black and White populations of the United States, identify the significance of selection and mobility as potential factors producing the crossover phenomenon, and make diagnostic use of them.

Adolescent↗
PubMed2002

Variability and vulnerability at the ecological level: implications for understanding the social determinants of health.

OBJECTIVES: We examined variability in disease rates to gain understanding of the complex interactions between contextual socioeconomic factors and health. METHODS: We compared mortality rates between New York and California counties in the lowest and highest quartiles of socioeconomic status (SES), assessed rate variability between counties for various outcomes, and examined correlations between outcomes' sensitivity to SES and their variability. RESULTS: Outcomes with mortality rates that differed most by county SES were among those whose variability across counties was high (e.g., AIDS, homicide, cirrhosis). Lower-SES counties manifested greater variability among outcome measures. CONCLUSIONS: Differences in health outcome variability reflect differences in SES impact on health. Health variability at the ecological level might reflect the impact of stressors on vulnerable populations.

Adolescent↗