4,030 research outputs found
Recommended from our members
An ecological survey of the Gulf of Naples area : conducted during September 15 to October 15, 1976, for the Region of Campania
Submitted to Assessore Dr. Silvio Pavia, Region of Campania, Naples, Italy 80100, June 20, 1977Marine Scienc
Recommended from our members
Water quality of Texas bays (nutrients, trace elements and toxic compounds)
This manuscript is designed to compare the nutrient balances and trace element significance in Texas Bays and Estuaries. The task of assigning water quality criteria in all estuarine waters rests with the federal Environmental Protection Agency. However, the Texas Bays and Estuaries represent a unique range of environments of the U.S. Coast that stand alone and therefore must be assigned standards appropriate to the environment. Therefore we have compared several Texas Bays relative to nutrients and trace elements through an analysis of data from our files, a life history data bank from literature survey, a study of the Corpus Christi area, personal communication with a wide range of individuals and information from the Texas Water Quality Board, Texas Water Development Board, the U.S. Geological Survey and the State Health Department.May 30, 1974Taken in part from a report on Development of Biological Criteria, Establishment of Guidelines for Texas Coast Management IAC-(74-75)-0685 NSF RANN-61-34870xMarine Scienc
Recommended from our members
Sportfishing creel census pilot study
The sportfishing creel census project was originated to obtain information relating to the use of the Corpus Christi Bay area for sportfishing, the amount of fish caught and other environmental information relating to the total productivity cycles of the bay system. The Census is to be conducted during the summer months of June, July and August 1974 and the pilot study was made during August 1973. The total catch will be used in a current project to assess carbon, nitrogen, phosporous input and output to the bay system.March 15, 1974To The Lower Nueces River Water Supply DistrictMarine Scienc
Recommended from our members
Texas coastal zone biotopes : an ecography : interim report for the Bay and Estuary Management Program (CRMP)
November 1972Because esthetics, biological environment and physiography are so interrelated and have changeable meanings in various environments, we are obligated to think of the environment in terms of biological change, as environmental protection is presently a basis for much dialogue and sometimes controversy. To do this we have chosen an old concept and adapted it to identify the relationships among biological communities that may be changed when man or nature modifies the coastal environment. The chosen term is BIOTOPE, which is defined in Webster's as a region uniform in environmental conditions and in populations of animals and plants for which it is the habitat. Although the biological environment may appear to the layman as either diverse or uniform and without pattern, there are recognizable biotic assemblages that have some degree of relationship in their composition. Such recognizable assemblages may cover wide areas, such as the extensive turtle grass flats, or may be discrete small units, such as an oyster reef. Thus we have adapted the term BIOTOPE to identify such assemblages and initially suggest the following eighteen examples listed in Table 1. Thirteen of them plus an overview are illustrated. ... If the concept of the BIOTOPE is to be used to describe common, recognizable Texas Gulf coast communities, then we can use these descriptions to demonstrate the results of changes. For example, if one plans to dredge a grass flat to produce a spoil bank and a channel, the Biotopes of these three areas can be compared to allow the decision maker to evaluate how the change may affect the area involved. Because the decision maker is not always scientifically oriented, we have elected to describe the Biotope by artists' renditions accompanied with lists of common and scientific names of major species of plants and animals and a description of the relative productivity of the major organisms in the area.Supported in part by Coastal Resources Management Program, Office of the Governor, IAC (72-73)-806, and The National Science Foundation RANN, Grant GI-34870XMarine Scienc
Recommended from our members
The microbiological corrosion of iron
Office of Naval Research, Annual Progress Report, January 1, 1960-December 1, 1960 : Marine MicrobiologyTo study the properties of bacteria which are pertinent to the microbiological corrosion of iron in natural marine environments: (1) bacterial consumption of oxygen and subsequent production of oxygen differential corrosion cells, (2) the production of corrosive acids, and (3) microbial hydrogenase enzyme activity and its effect on the depolarization of metallic iron surfacesUnited States. Office of Naval Research; University of Texas, Institute of Marine ScienceMarine Scienc
Recommended from our members
Biological uses criteria
The purpose of this interdisciplinary project is to formulate the criteria for coastal zone use and development. The portion assigned to our group is to develop Biological Use Criteria. Biological Use Criteria are defined here as the environmental quality which will permit natural communities of flora and fauna and the natural productivity of the Texas bays and estuaries, including their shoreline areas. Biological use then may be identified in terms of environmental quality where known inputs may cause changes in the natural balance of living systems. Such criteria are difficult to estimate or identify because of the diversity of communities and the continual natural variations in environmental conditions in our estuarine systems.May 1973Coordinated through Division of Natural Resources and Environment, University of Texas at AustinPrepared for Research Applied to National Needs Program, National Science Foundation. GI-34870XPrepared for Division of Planning Coordination, Office of the Governor of Texas Interagency Cooperation. IAC(72-73)-806Marine Scienc
Recommended from our members
Ecological relationships between marine microorganisms and hydrocarbons in the OEI study area, Louisiana
Supported by Gulf Universities Research Consortium, Project #OE73HJMCataloged from imperfect copy: all after leaf 20 wantingSeven cruise projects were conducted in association with the Louisiana Offshore Ecological Investigation (OEI) to determine the relationships between microorganisms and hydrocarbons in surface waters. Techniques were developed to take surface samples and to determine bacterial numbers, hydrocarbon content, and the response of indigenous microorganisms to various added hydrocarbon molecules. The numbers of heterotrophic bacteria as determined by dilution techniques varied from 10 to 10,000 per ml. The hydrocarbon oxidizing organisms varied from 10 to 100,000 per liter with maxima in the month of January. Hydrocarbon concentrations varied from 0.03 to 0.6 micrograms per liter. There was no correlation between the numbers of oil degraders and hydrocarbon concentration found. This may be the result of the in situ low concentrations of hydrocarbons which would limit microbial response. The numbers of bacteria and hydrocarbons were similar to control areas in the eastern and western parts of the Gulf. BOD experiments conducted to measure the response of the microorganisms to various low and high molecular weight paraffinic and aromatic hydrocarbons indicated that all hydrocarbons were oxidized by some of the mixed indigenous microorganisms. These data suggest that an adequate inoculum was naturally present to respond to oil contamination in nature. The high numbers of hydrocarbon oxidizing microorganisms associated with January hydrographic data may indicate that the upland leaching and other contamination of hydrocarbons in the Mississippi River produce the noted microbial response for that month. The dominant saturated hydrocarbons and isoprenoids ranged from C-15 to C-41. Water from Timbalier Bay generally contained higher concentrations than offshore samples and exhibited a more pronounced odd-even preference in the range C-24 to C-33. GC-MS analysis of the dominant paraffins revealed a characteristic biomodal distribution dominated by C-17 and pristane and C-25 to C-35 with an unresolved envelope. No buildup of specific n-paraffin molecules was found, which data corresponded to BOD results of added hydrocarbons to indigenous microflora.Marine Scienc
A cortical potential reflecting cardiac function
Emotional trauma and psychological stress can precipitate cardiac arrhythmia and sudden death through arrhythmogenic effects of efferent sympathetic drive. Patients with preexisting heart disease are particularly at risk. Moreover, generation of proarrhythmic activity patterns within cerebral autonomic centers may be amplified by afferent feedback from a dysfunctional myocardium. An electrocortical potential reflecting afferent cardiac information has been described, reflecting individual differences in interoceptive sensitivity (awareness of one's own heartbeats). To inform our understanding of mechanisms underlying arrhythmogenesis, we extended this approach, identifying electrocortical potentials corresponding to the cortical expression of afferent information about the integrity of myocardial function during stress. We measured changes in cardiac response simultaneously with electroencephalography in patients with established ventricular dysfunction. Experimentally induced mental stress enhanced cardiovascular indices of sympathetic activity (systolic blood pressure, heart rate, ventricular ejection fraction, and skin conductance) across all patients. However, the functional response of the myocardium varied; some patients increased, whereas others decreased, cardiac output during stress. Across patients, heartbeat-evoked potential amplitude at left temporal and lateral frontal electrode locations correlated with stress-induced changes in cardiac output, consistent with an afferent cortical representation of myocardial function during stress. Moreover, the amplitude of the heartbeat-evoked potential in the left temporal region reflected the proarrhythmic status of the heart (inhomogeneity of left ventricular repolarization). These observations delineate a cortical representation of cardiac function predictive of proarrhythmic abnormalities in cardiac repolarization. Our findings highlight the dynamic interaction of heart and brain in stress-induced cardiovascular morbidity
Intergalactic Dust Extinction in Hydrodynamic Cosmological Simulations
Recently Menard et al. detected a subtle but systematic change in the mean
color of quasars as a function of their projected separation from foreground
galaxies, extending to comoving separations of ~10Mpc/h, which they interpret
as a signature of reddening by intergalactic dust. We present theoretical
models of this remarkable observation, using SPH cosmological simulations of a
(50Mpc/h)^3 volume. Our primary model uses a simulation with galactic winds and
assumes that dust traces the intergalactic metals. The predicted galaxy-dust
correlation function is similar in form to the galaxy-mass correlation
function, and reproducing the MSFR data requires a dust-to-metal mass ratio of
0.24, about half the value in the Galactic ISM. Roughly half of the reddening
arises in dust that is more than 100Kpc/h from the nearest massive galaxy. We
also examine a simulation with no galactic winds, which predicts a much smaller
fraction of intergalactic metals (3% vs. 35%) and therefore requires an
unphysical dust-to-metal ratio of 2.18 to reproduce the MSFR data. In both
models, the signal is dominated by sightlines with E(g-i)=0.001-0.1. The
no-wind simulation can be reconciled with the data if we also allow reddening
to arise in galaxies up to several x 10^10 Msun. The wind model predicts a mean
visual extinction of A_V ~0.0133 mag out to z=0.5, with a
sightline-to-sightline dispersion similar to the mean, which could be
significant for future supernova cosmology studies. Reproducing the MSFR
results in these simulations requires that a large fraction of ISM dust survive
its expulsion from galaxies and its residence in the intergalactic medium.
Future observational studies that provide higher precision and measure the
dependence on galaxy type and environment will allow detailed tests for models
of enriched galactic outflows and the survival of IG dust.Comment: Matches version accepted by MNRA
- …