1,046 research outputs found
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Body mass index and health care utilization in diabetic and nondiabetic individuals.
BackgroundAlthough controversial, most studies examining the relationship of body mass index (BMI) with mortality in diabetes suggest a paradox: the lowest risk category is above normal weight, versus normal weight in nondiabetic persons. One proposed explanation is greater morbidity of diabetes in normal weight persons. If this were so, it would suggest a health care utilization paradox in diabetes, paralleling the mortality paradox, yet no studies have examined this issue.ObjectiveTo compare the relationship of BMI with health care utilization in diabetic versus nondiabetic persons.DesignPopulation-based cross-sectional study.SubjectsAdults in the 2000-2011 Medical Expenditures Panel Surveys (N=120,389).MeasuresTotal health care expenditures, hospital utilization (≥1 admission), and emergency department utilization (≥1 visit). BMI (kg/m) categories were: <20 (underweight); 20 to <25 (normal); 25 to <30 (overweight); 30 to <35 (obese); and ≥35 (severely obese). Adjustors were age, sex, race/ethnicity, income, health insurance, education, smoking, co-morbidity, urbanicity, region, and year.ResultsAmong diabetic persons, adjusted mean total health care expenditures were significantly lower in obese versus normal weight persons (513-229, 95% CI, -2; P=0.052). Findings for hospital and emergency department utilization exhibited similar patterns.ConclusionsNormal weight diabetic persons used substantially more health care than their overweight and obese counterparts, a difference not observed in nondiabetic persons. These differences support the plausibility of a BMI mortality paradox related to greater morbidity of diabetes in normal weight than in heavier persons
Editor\u27s Commentary: The relationship of vertical turbulence and spring diatom flowerings
The dynamics of spring blooms of phytoplankton in temperate waters are usually associated with H.U. Sverdrup’s 1953 “critical depth” model. However, more than a decade earlier, Gordon Riley published a statistical and mechanistic analysis of data he had gathered over two spring “flowerings” on Georges Bank..
Compulsory arbitration: the next 40 years
This comment argues that there must be a follom-up study to James Holt's Compulsory arbitration in New Zealand - the first fourty years and examines three issues important to any such study: the formulation of new unions after 1936: the way the arbitration system has protected vulnerable groups of workers: and women's wages and equal pay
Unions in common cause: the New Zealand Federation of Labour 1937–88
Unions in Common Cause is the first detailed study of the history of the New Zealand Federation of Labour (1937-88). Based on a conference held in 2007, this book includes chapters by four of our leading labour historians and contributions by past and present activists. It is richly illustrated. The FOL’s enduring legacy was to create a national voice for workers, a central organisation to represent their collective interests. In bad times, as well as good, that voice has continued to be heard.NZ Work & Labour Market Institute at Auckland University of Technology, the Labour History Project, the NZ Council of Trade Unions, the NZ Amalgamated Engineering Printing & Manufacturing Union, the NZ Dairy Workers Union Te Runanga Wai U, the Maritime Union of NZ, the NZ Meat Workers & Related Trades Union, the National Distribution Union, the Rail & Maritime Transport Union and the Service & Food Workers Union Nga Ringa Tot
Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf.
Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (ΔΨstem-leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO₂ concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO₂ concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO₂ on g s. The positive relationship between k leaf and E minimized variation in ΔΨstem-leaf. This enables leaves to minimize variation in Ψleaf and maximize g s and CO₂ assimilation rate over the diurnal course of evaporative demand
Is expanding Medicare coverage cost-effective?
Background: Proposals to expand Medicare coverage tend to be expensive, but the value of
services purchased is not known. This study evaluates the efficiency of the average private
supplemental insurance plan for Medicare recipients.
Methods: Data from the National Health Interview Survey, the National Death Index, and the
Medical Expenditure Panel Survey were analyzed to estimate the costs, changes in life expectancy,
and health-related quality of life gains associated with providing private supplemental insurance
coverage for Medicare beneficiaries. Model inputs included socio-demographic, health, and health
behavior characteristics.
Parameter estimates from regression models were used to predict quality-adjusted life years
(QALYs) and costs associated with private supplemental insurance relative to Medicare only.
Markov decision analysis modeling was then employed to calculate incremental cost-effectiveness
ratios.
Results: Medicare supplemental insurance is associated with increased health care utilization, but
the additional costs associated with this utilization are offset by gains in quality-adjusted life
expectancy. The incremental cost-effectiveness of private supplemental insurance is approximately
$24,000 per QALY gained relative to Medicare alone.
Conclusion: Supplemental insurance for Medicare beneficiaries is a good value, with an
incremental cost-effectiveness ratio comparable to medical interventions commonly deemed
worthwhile
Dinoflagellate blooms and physical systems in the Gulf of Maine
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 1990Numerous studies have shown dinoflagellate blooms to be
closely related to density discontinuities and fronts in the ocean. The
spatial and temporal patterns of the dinoflagellate population
depend on the predominant mode of physical forcing, and its scales
of variability. The present study combined field sampling of
hydrographic and biological variables to examine the relationship of
dinoflagellate population distributions to physical factors along the
southwestern cost of the Gulf of Maine.
A bloom of Ceratium longipes occurred along this coast during
the month of June, 1987. A simple model which coupled along-isopycnal
diffusion with the logistic growth equation suggested that
the cells had a growth rate of about 0.1 d-1 , and had reached a
steady horizontal across-shelf distribution within about 10 d.
Fur~her variations in population density appeared to be related to
fluctuations of light with periods of -10 d. To our knowledge, this
was the first use of this simple diffusion model as a diagnostic tool
for quantifying parameters describing the growth and movement of
a specific phytoplankton population.
Blooms of the toxic dinoflagellate, Alexandrium tamarense
have been nearly annual features along the coasts of southern
Maine, New Hampshire and Massachusetts since 1972; however the
mechanisms controlling the distribution of cells and concomitant
shellfish toxicity are relatively poorly understood. Analysis of field
data gathered from April to September, 1987-1989, showed that in
two years when toxicity was detected in the southern part of this
region, A. tamarense cells were apparently transported into the
study area between Portsmouth and Cape Ann, Massachusetts, in a
coastally trapped buoyant plume. This plume appears to have been
formed off Maine by the outflow from the Androscoggin and Kennebec Rivers. Flow rates of these rivers, hydrographic sections,
and satellite images suggest that the plume had a duration of about
a month, and extended alongshore for several hundred kilometers.
The distribution of cells followed the position of the plume as it was
influenced by wind and topography. Thus when winds were
downwelling-favourable, cells were moved alongshore to the south,
and were held to the coast; when winds were upwelling-favourable,
the plume sometimes separated from the coast, advecting the cells
offshore.
The alongshore advection of toxic cells within a coastally
trapped buoyant plume can explain the temporal and spatial
patterns of shellfish toxicity along the coast. The general observation
of a north-to-south temporal trend of toxicity is consistent with the
southward advection of the plume. In 1987 when no plume was
present, Alexandrium tamarense cells were scarce, and no toxicity
was recorded at the southern stations. A hypothesis was formulated
explaining the development and spread of toxic dinoflagellate
blooms in this region. This plume-advection hypothesis included:
source A. tamarense populations in the north, possibly associated
with the Androscoggin and Kennebec estuaries; a relationship
between toxicity patterns and river flow volume and timing of flow
peaks; and a relationship between wind stresses and the distribution
of low salinity water and cells. Predictions of the plume-advection hypothesis were tested
with historical records of shellfish toxicity, wind speed and direction,
and river flow. The predictions tested included the north-south
progression of toxic outbreaks, the occurrence of a peak in river flow
prior to the PSP events, the relationship of transit time of PSP
toxicity along the coast with river flow volume, and the influence of
surface wind stress on the timing and location of shellfish toxicity.
All the predictions tested were supported by the historical records.
In addition it was found that the plume-advection hypothesis
explains many details of the timing and spread of shellfish toxicity,
including the sporadic nature of toxic outbreaks south of
Massachusetts Bay, and the apparently rare occurrence of toxicity
well offshore on Nantucket Shoals and Georges Bank.This research was supported by
ONR contract N00014-87-K-0007 and ONR grant N00014-89-J-111
to Donald M. Anderson, and NOAA Office of Sea Grant contract
NA86AA-D-SG090
Plankton production in tidal fronts: A model of Georges Bank in summer
A two-dimensional (x,z) coupled physical-biological model of the plankton on Georges Bank during the summer was developed. The physical portion included a primitive-equation turbulence-closure model with topography-following σ coordinate. The biological model was a simple N-P-Z model. Tidal forcing at the model boundary generated a well-mixed region on the top of the bank, and strong tidal fronts at the bank edges. Biological fields were homogenized on the bank, while pronounced phytoplankton patches and horizontal gradients in properties developed in the fronts. The biomasses and fluxes of biological variables in the model agreed well with field estimates from Georges Bank. The phytoplankton in the well-mixed region of the bank were found to be nutrient replete, with f ratios of about 0.3. Values up to 0.7 were found for the f ratios in the fronts, where phytoplankton patches were supported by vertical fluxes of nutrients from below the euphotic zone. While the patterns of patchiness in the fronts were stable between tidal periods, the structure of patches and fluxes changed dramatically during a tidal cycle. Enhanced vertical mixing and horizontal gradients formed during a brief period of the tide, accounting for much of the cross-frontal nutrient flux. Sampling in such a dynamic system would be very difficult, and probably miss the essential features
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The burden of disease associated with being African-American in the United States and the contribution of socio-economic status
The burden of disease associated with being African-American in the US, and the contribution of socio-economic status (SES) to that burden have not been quantified. We derived burden of disease estimates for African-Americans and whites by age group, with and without adjustment for SES (income and education). We used (1) EQ-5D Index scores from the 2000 US Medical Expenditure Panel Survey to derive quality-adjusted life year (QALY) compatible estimates of health-related quality of life (HRQL); (2) 1990–1992 US National Health Interview Survey data linked to National Death Index data through 1995 to derive mortality risks; and (3) 2000 US mortality data from the National Center for Health Statistics to derive current mortality estimates for the US population. We found that relative to whites, African-Americans suffer 67,000 more deaths annually, resulting in 2.2 million years of life lost, and 1.1 million years after SES adjustment. Total QALYs lost (HRQL and mortality) dropped from 2.3 million to 902,000 after SES adjustment. SES differences between African-Americans and whites appear to explain all the HRQL disparity but only half the mortality disparity. Better understanding of the disparate effects of SES may inform interventions to address health disparities adversely affecting African-Americans
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