A Preliminary study of community oxygen metabolism in the vicinity of the C. P. Crane electric power generating station : final report

The community metabolism of the waters in the vicinity of C. P. Crane electric power generating station is reported for two seasonal periods in 1979. The early autumn period (October) is generally characterized by warm water temperatures (20°C) and an insolation period of 11 hours; the late autumn period (December) is generally characterized by cold water temperatures (4-6°C) and an insolation period of approximately 9 hours. Both sets of observations, were taken during periods which were significantly influenced by winds. ... more

Bacterial Biomass And Heterotrophic Potential in the Waters of the Chesapeake Bay Plume and Contiguous Continental Shelf

Bacterial populations in Chesapeake Bay and contiguous shelf waters are significant to such essential processes as mineralization, nutrient recycling, degradation of pollutants and biomass production. However, our understanding of such dynamic relationships of physical and chemical factors to bacterial biomass and activities in Chesapeake Bay plume waters is limited. The availability of synoptic hydrographic (and remotely sensed physical-chemical) data obtained simultaneously with measurement of of microbial biomass and activity presented an opportunity to examine such relationships.https://scholarworks.wm.edu/vimsbooks/1130/thumbnail.jp

The Effect of Tropical Storm Agnes as Reflected in Chlorophyll A and Heterotrophic Potential of the Lower Chesapeake Bay

A hydrographic station (Station Y) at the mouth of the York River (37°14.6\u27N, 76°23.4\u27W) was under biological surveillance for one year prior to the arrival of Tropical Storm Agnes. For one full year following this storm, these measurements were continued. In addition, the chlorophyll a and heterotrophic potential measurements were incorporated into an ongoing zooplankton sampling program of the lower Chesapeake Bay below 37°40\u27N latitude.https://scholarworks.wm.edu/vimsbooks/1071/thumbnail.jp

Acute biological effects of chemically dispersed oil spillage : final report to the American Petroleum Institute

Primary productivity, heterotrophic potential, chlorophyll i! and phaeophytin, ATP, and direct bacterial counts were measured in the sea surface layer under controlled spills of La Rosa and Murban crude oils following immediate dispersal with the EXXON dispersant, Corexit 9527. Tests were conducted off New York on November 9, 1978. The response of productivity to dispersed oil appeared as an initial increase in rates, a reduction to minimal rates 1-2 hours after dispersion, and a return to pre-spill rates after 3 hours. Comparison of productivity measurements from the two tests suggested a more efficient and rapid dispersion of the somewhat lighter La Rosa crude. Heterotrophic uptake at one meter below the La Rosa spill mirrored productivity results; missing samples at the Murban spill prohibited interpretation. While oil and dispersant appeared to have little effect on chlorophyll-~ and direct bacterial counts, ATP concentrations decreased· to below detectable limits shortly after the application of the dispersant. Phaeophytin, expressed as a percentage of chlorophyll, varied inversely with ATP in both tests

Plant geography and water quality data for Chesapeake Bay waters of Virginia\u27s Eastern Shore

Plant geography and water quality data were collected in shallow water near Cape Charles and Occohannock Creek, Virginia on two occasions. Data from April, 1978 included hydrography, distribution and abundance of -submerged aquatic vegetation, phytoplankton census, and water clarity data. Data from May, 1978 included hydrography, phytoplankton census, water clarity, and primary productivity data. The May data collection was coincident with an overflight of the NASA JSC C-130 aircraft (6600 m) acquiring color infrared photography and multispectral scanner data; cell concentrations reached 105/ml, chlorophyll~ 72 pg/1, and suspended sediment 94 mg/1.

MALATE DEHYDROGENASE ISOZYMES OF DIFFERENT STAGES OF CHESAPEAKE BAY JELLYFISH

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Reconstructing primary production in a changing estuary: A mass balance modeling approach

Estuarine primary production (PP) is a critical rate process for understanding ecosystem function and response to environmental change. PP is fundamentally linked to estuarine eutrophication, and as such should respond to ongoing efforts to reduce nutrient inputs to estuaries globally. However, concurrent changes including warming, altered hydrology, reduced input of sediments, and emergence of harmful algal blooms (HABs) could interact with nutrient management to produce unexpected changes in PP. Despite its fundamental importance, estuarine PP is rarely measured. We reconstructed PP in the York River Estuary with a novel mass balance model based on dissolved inorganic nitrogen (DIN) for the period 1994–2018. Modeled PP compared well to previous estimates and demonstrated a long-term increase and down-estuary shift over the study period. This increase occurred despite reductions in discharge, flushing time, DIN loading, and DIN standing stock over the same period. Increased PP corresponded to increased water temperature, decreased turbidity and light attenuation, and increased photic depth and assimilation ratio, suggesting that phytoplankton in the York River Estuary have become more efficient at converting nutrients into biomass primarily due to a release from light limitation. The increase in PP also coincided with the increasing occurrence of late summer HABs in the lower York River Estuary, including the emergence of a second bloom-forming dinoflagellate in 2007. Results demonstrate how changes concurrent with nutrient management could alter expected system responses and illustrate the utility of the mass balance approach for estimating critical rate processes like PP in the absence of observations

Differences in the mix of patients among medical specialties and systems of care. Results from the medical outcomes study

OBJECTIVE: To determine differences in the mix of patients among medical specialties and among organizational systems of care. STUDY DESIGN: Cross-sectional analysis of 20,158 adults (greater than or equal to 18 years of age) who visited providers\u27 offices during 9-day screening periods in 1986. Patient and physician information was obtained by self-administered, standardized questionnaires. SETTING: Offices of 349 physicians practicing family medicine, internal medicine, endocrinology, and cardiology within health maintenance organizations, large multispecialty groups, and solo or small single-specialty group practices in three major US cities. OUTCOME MEASURES: Demographic characteristics, prevalence of chronic disease, disease-specific severity of illness, and functional status and well-being. RESULTS: Among patients with selected physician-reported chronic illnesses (diabetes, hypertension, recent myocardial infarction, or congestive heart failure), increasing levels of severity were associated with decreasing levels of functional status and well-being and with increased hospitalizations, more physician visits, and higher numbers of prescription drugs. Compared with patients of general internists, patients of cardiologists were older (56 vs 47 years, P less than .01), had worse functional status and well-being scores (P less than .01), and carried more chronic diagnoses (mean 1.32 vs 1.02, P less than .01); patients of family practitioners were younger (40 vs 47 years, P less than .01) and more functional (P less than .01), carried fewer chronic diagnoses (0.70 vs 1.02, P less than .01), and (among diabetic patients only) had lower disease-specific severity scores (2.06 vs 2.30 on a five-point scale, P less than .01). Compared with patients in health maintenance organizations, patients visiting solo practitioners under fee-for-service payment were older (50 vs 45 years, P less than .01) and sicker (had worse physical functioning) and had a higher mean number of chronic diagnoses (1.10 vs 0.93, P less than .01). CONCLUSION: Patient mix is related to utilization and differs significantly across medical specialties and systems of care. These differences must be taken into account when interpreting variations in utilization and outcomes across specialties and systems, and when considering alternative policies for payment

Variations in resource utilization among medical specialties and systems of care. Results from the medical outcomes study

OBJECTIVE: To examine whether specialty and system of care exert independent effects on resource utilization. STUDY DESIGN: Cross-sectional analysis of just over 20,000 patients (greater than or equal to 18 years of age) who visited providers\u27 offices during 9-day periods in 1986. Patient- and physician-provided information was obtained by self-administered questionnaires. SETTING: Offices of 349 physicians practicing family medicine, internal medicine, endocrinology, and cardiology within health maintenance organizations, large multispecialty groups, and solo practices or small single-specialty group practices in three major US cities. OUTCOME MEASURES: Indicators of the intensity of resource utilization were examined among four medical specialties (family practice, general internal medicine, cardiology, and endocrinology) and five systems of care (health maintenance organization, multispecialty group-fee-for-service, multispecialty group-prepaid; solo practice and single-specialty group-fee-for-service, and solo practice and single-specialty group-prepaid) before and after controlling for the mix of patients seen in these offices. The indicators of resource utilization were hospitalizations, annual office visits, prescription drugs, and common tests and procedures, with rates estimated on both a per-visit and per-year basis. RESULTS: Variation in patient mix was a major determinant of the large variations in resource use. However, increased utilization was also independently related to specialty (cardiology and endocrinology), fee-for-service payment plan, and solo and single-specialty group practice arrangements. After adjusting for patient mix, solo practice/single-specialty groups-fee-for-service had 41% more hospitalizations than health maintenance organizations. General internists had utilization rates somewhat greater than family physicians on some indicators. CONCLUSION: Although variations in patient mix should be a major determinant of variations in resource use, the independent effects of specialty training, payment system, and practice organization on utilization rates need further explication. The 2- and 4-year outcomes now being analyzed will provide information critical to interpretation of the variations reported herein