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At least 19 recordsLinked to original sources
PubMed1979

Anaerobic metabolism of immediate methane precursors in Lake Mendota.

Lake Mendota sediments and the immediate overlying water column were studied to better understand the metabolism of the methanogenic precursors H2/CO2 and acetate in nature. The pool size of acetate (3.5 microns M) was very small, and the acetate turnover time (0.22h) was very rapid. The dissolved inorganic carbon pool was shown to be large (6.4 to 8.3 mM), and the turnover time was slow (111 H.). CO2 was shown to account for 41 +/- 5.5% of the methane produced in sediment. Acetate and H2/CO2 were simultaneously converted to CH4. The addition of H2 to sediments resulted in an increase specific activity of CH4 from H(14)CO3- and a decrease in specific activity of CH4 from [2-14C]acetate. Acetate addition resulted in a decrease in specific activity of CH4 from H(14)CO3-. The metabolism of H(14)CO3- or [2-14C]acetate to 14CH4 was not inhibited by addition of acetate or H2. After greater than 99% of added [2-14C]acetate had been turned over, 42% of the label was recovered as 14CH4 20% was recovered as 14CO2 and 38% was incorporated into sediment. Inhibitor studies of [2-14C]acetate metabolism in sediments demonstrated that CHCl3 completely inhibited CH4 formation, but not CO2 production. Air and nitrate addition inhibited CH4 formation and stimulated CO2 production, whereas fluoroacetate addition totally inhibited acetate metabolism. The oxidation of [2-14C]acetate to 14CO2 was shown to decrease with time when sediment was incubated before the addition of label, suggesting depletion of low levels of an endogenous sediment electron acceptor. Acetate metabolism varied seasonally and was related to the concentration of sulfate in the lake and interstitial water. Methanogenesis occurred in the sediment and in the water immediately overlying the sediment during period of lake stratification and several centimeters below the sediment-water interface during lake turnovers. These data indicate that methanogenesis in Lake Mendota sediments was limited by "immediate" methane precursor availability (i.e., acetate and H2), by competition for these substrates by nonmethanogens, and by seasonal variations which altered sediment and water chemistry.

Acetates↗
PubMedDate not supplied

[Proboscis worm, Echinorhynchus gadi (Zoega) from a relict cod of Lake Mogil'noye].

Data on the extensiveness and intensity of infection of Kildin island cod with Echinorhynchus gadi in various seasons are given. E. gadi was proved to have a one-year life cycle and Gammarus duebeni as an intermediate host in the lake. A change of the parasite generations occurs in late summer--autumn. A high extensiveness (100%) and intensity of Kildin cod infection with E. gadi depends on the feeding habits (monophagy) and narrow distribution range of the host. Infection intensity is directly correlated with the fish age. Selfregulation of the parasite quantity in the host's intenstine is an important factor affecting the existence of E. gadi population in Lake Mogilnoye.

Acanthocephala↗
PubMed2026

PheBee: A Graph-Aware System for Scalable, Traceable, and Semantic Phenotyping.

OBJECTIVES: Phenotype-driven workflows in clinical and translational research require standardized ontology-based representation, ontology-aware cohort discovery, and provenance inspection for each assertion. Existing approaches optimize either for semantic traversal or scalable batch analytics, but not both. We describe PheBee, a hybrid system that links semantic assertions to scalable evidence storage via a deterministic identifier, preserving provenance while supporting ontology-aware discovery at cohort scale. MATERIALS AND METHODS: PheBee represents phenotype assertions in a knowledge graph as ontology-linked nodes with clinical modifier context (e.g., negated, family history), and stores supporting evidence records in a scalable row-oriented evidence table for cohort-scale access. The two layers are connected by a deterministic identifier enabling stable joins across repeated ingestions without duplicating high-volume evidence in the graph. We evaluated PheBee using synthetic datasets designed to exercise end-to-end ingestion and query workflows. RESULTS: Functional evaluation validated hierarchical term expansion, qualifier-aware retrieval, duplicate-free assertion handling under re-ingestion, and privacy-conscious management of subjects shared across multiple research projects. At scale (10,000 subjects producing 12M evidence records) PheBee completed ingestion in ~30 minutes and responded to interactive queries within 6 seconds under concurrent load. DISCUSSION: PheBee exposes a unified API for ontology-aware cohort discovery with hierarchical term expansion, subject-centric retrieval of phenotypes and clinical modifiers, and evidence and provenance queries. Its data model aligns with GA4GH Phenopackets, facilitating interoperability with phenotype exchange standards. CONCLUSION: By combining ontology-aware semantics with scalable, provenance-bearing evidence storage, PheBee provides a practical open-source foundation for phenotype-driven research workflows that demand both semantic precision and cohort-scale traceability.

cohort studies↗
PubMed1991

Epidemiology of Great Lakes bald eagles.

Historical data are provided to support the hypothesis that organochlorine chemicals introduced into the Great Lakes ecosystem following World War II are the cause of reproductive loss among bald eagles (Haliaeetus leucocephalus) in the basin. This is supported with data on concurrent population fluxes of extrabasin North American bald eagle populations and the European white-tailed sea eagle (Haliaeetus albicillus) where the same chemicals were produced and released. Organochlorine chemicals appear as a unique stress on Great Lakes bald eagle populations when compared with stresses on successful populations of bald eagles continentwide. Shoreline birds bear significantly higher concentrations of these persistent toxics than inland birds. Association between contaminated prey and elevated concentrations of PCBs, DDT, and DDE in Great Lakes bald eagles are presented. A fledging ratio is used to support the hypothesis that maternal prezygotic exposure affects the viability of embryos and chicks. The ratio of the mean number of fledglings per successful territory to the mean number of fledglings per active territory, when the numerator is greater than 1.4, provides an index of exposure to contaminants by parental animals and affected offspring. When the ratio is greater than 2, parental exposure to organochlorine chemicals should be considered. The adverse effects of prezygotic exposure to the same contaminants in other animal species dependent upon Great Lakes fish, and extrabasin bald eagle populations dependent upon contaminated fish, provide consistency to the argument. The mechanism of action of the organochlorine chemicals further strengthens the causal argument indicting DDT, DDE, and PCBs. A strong association between DDT/DDE and bald eagle reproductive success is provided. However, the role of PCBs is not ruled out. Only data for total PCB concentrations in bald eagle tissue are available, and until specific PCB congeners are quantified there will be uncertainty concerning PCB's role in the Great Lakes bald eagle's lack of success.

Animals↗
PubMed1991

Cause-effect linkages between chemicals and populations of mink (Mustela vison) and otter (Lutra canadensis) in the Great Lakes basin.

Following outbreaks of reproductive failure in commercial ranching operations, laboratory experiments showed that mink are extremely sensitive to organochlorine chemicals, particularly PCBs and dioxins. The purpose of this paper is to test the hypothesis that, since wild mink are exposed to these compounds through consumption of Great Lakes fish, they might exhibit reproductive dysfunction and population declines. The otter, another piscivorous animal, should show the same effects. The available information is reviewed according to five epidemiological criteria. Harvest data are presented as a surrogate for the population status of mink and otters in certain locations around the Great Lakes. Data from Ohio show that the mink harvest between 1982 and 1987 from contaminated counties bordering Lake Erie was consistently lower (380 animals per year) than those from counties removed from Lake Erie (850 animals per year), suggesting an effect of chemicals on the status of mink populations. Preliminary studies from Ontario also suggest that mink harvest is lower in potentially "high PCB exposure areas" compared with lower exposure areas. Evidence is also presented on the harvest data for otters taken from four New York State counties adjacent to Lake Ontario and the St. Lawrence River. The harvest data from these four counties show that between 1960 and early 1970 otter harvest remained stable but has since increased. Increased harvest is consistent with improved water quality in Lake Ontario during the past 15 yr. Data relating to strength of association between chemicals and populations of mink and otter are weak and need to be further analyzed. The specificity of the effects of the chemicals on mink reproduction and mortality is well established from toxicological experiments, but there is poor resolution of the information on effects using field data. The strongest case for a causal relationship comes from consideration of the coherence criterion. In conclusion, before a causal link can be drawn between the status of mink and otter populations and exposure to organochlorine chemicals from the Great Lakes, a large amount of research and data analysis needs to be undertaken.

Animals↗
PubMed1988

Schistosomiasis in Kano State, Nigeria. II. Field studies on aestivation in Bulinus rohlfsi (Clessin) and B. globosus (Morelet) and their susceptibility to local strains of Schistosoma haematobium (Bilharz).

Aestivation patterns in Bulinus rohlfsi and B. globosus were studied by digging transects across the floor of their dried habitats and by monitoring changes in snail population structure during the period when the habitats were flooded. Bulinus rohlfsi, which inhabited a small man-made lake, was found to aestivate towards the bottom of its habitat, aestivation occurring during the last six weeks before the lake dried. The data on B. globosus from a temporary pool are less complete, but they show that this species also aestivates at the bottom of its habitat and can be found buried at depths up to 3 cm. A wide size range of both species of snail were found to aestivate, but there was differential mortality of young B. rohlfsi soon after the lake re-filled, and the optimally surviving size group of B. globosus was 9 mm. The beginning of aestivation in B. rohlfsi did not correlate with any of the physical parameters measured, but it coincided with the dying off of a bloom of unicellular algae. The importance of stimuli other than desiccation in the aestivation process of bulinids is stressed. Laboratory infections with isolates of Schistosoma haematobium showed that both Bulinus species were capable of transmitting local strains of the parasite and indicated the presence of snail host-specific strains.

Adaptation, Physiological↗
PubMed1991

Estimating frequency of disease findings from combined hospital databases: a UMLS project.

Merging data from the Salt Lake VA hospital database and the LDS hospital HELP system into a UMLS sponsored unified patient database has demonstrated that distribution of variables within a disease is hospital independent. Although disease prevalence is clearly not the same among hospitals, analysis of data within a disease group across hospitals can be done using such a merged database. This unified patient database would allow study of unusual diseases not possible using data from a single institution.

Databases, Factual↗
PubMed1992

Winter transport of Chernobyl radionuclides from a montane catchment to an ice-covered lake.

The amounts of 137Cs and 90Sr have been determined in the inflows and outflows of the Norwegian sub-alpine lake, Ovre Heimdalsvatn, in March/April during the period of ice-cover, when discharge is extremely stable. The lake is situated in an area contaminated by Chernobyl fallout. The transported course particulate plant material has been collected in traps; the particles and colloids have been removed from water samples by cross-flow ultrafiltration. On the basis of radionuclide inputs and outputs, lake budget calculations have been made for 137Cs and 90Sr during the period of ice-cover. Daily transport of radionuclides is considerably less than that observed during the spring snowmelt period when discharges are high. Size distribution patterns of Cs and Sr observed during winter are compared with previously published data from the same lake during the spring spate. The retention of 137Cs is similar in winter and spring, but retention of 90Sr is greater in winter.

Accidents↗
PubMedDate not supplied

[Microbiological characteristics of the lakes in the Yaroslavl region].

The paper presents data concerning the activity of microflora in water and ooze deposits of lakes of the Yaroslavl Region. Microbiological processes in water depend mainly on the rate of production or organic substance at the account of phytoplankton photosynthesis, which varies from 0.18 to 6.3 gC/m2. Destruction of organic substance in water of most lakes exceeded production. Production of bacterial biomass was within limits of 0.2--5.8 gC/m2/day and lower, as a rule, than production of phytoplankton. The number of bacteria in different lakes varied from 1.7 to 35 X 10(6) per 1 ml. Heterotrophic assimilation of carbon dioxide was rather high and reached 34 mcgC/litre/day, its ratio to biomass being ca. 6.8%. The total number of bacteria in ooze deposits of lakes varied from 0.6 to 2.7 X 10(9) g/m2. Aerobic destruction varied from 0.03 to 0.78 gC/m2.

Bacteria↗
PubMed1976

[The use of an enzyme-kinetic-method for bacteriological examinations of heavy polluted surface waters (author's transl)].

The greatest fraction of nutrients dissolved in water are organic substances which are decomposed, transformed and mineralized by heterotrophic microorganisms. For this reason, investigations concerning energy transfer in an aquatic ecosystem, or practical examinations of the pollution load of surface waters, cannot be set up when based exclusively on more or less good counts of microorganisms of the production or destruction group. Above all, it is important for heterotrophic bacteria that productivity parameters for these numerical estimations are also provided. PARSON and STRICKLAND were successful in measuring the uptake of organic material in waters with uptake-kinetic methods; HOBBIE and WRIGHT developed a method for measuring the uptake of marked test-substrates in certain concentration ranges. As a result, for these substrates it was possible to measure the turnover in natural populations. Consequently, after frequent improvement of the technique in determining the decomposition rates of individual organic substrates, a way was found not only to determine static descriptions of an aquatic biotope, but also to make possible a dynamic description of nutrient transfers. The kinetic parameters computed from these measurements are: the maximum uptake velocity (Vmax), the turnover velocity (Tt) and the transport constant (Kt) (Michaelis Constant). The maximum uptake velocity of a substrate can be regarded as the "heterotrophic capacity" of the biotope for this substrate. One restriction is, however, that only quickly assimilatable substrates can be used, as for example hexoses, organic acids, amino acids, etc. Since this technique was tested practically only in oligotrophic waters, this study undertakes to investigate its applicability in polluted biotopes and to answer the question whether a decomposition gradient is reflected in the kinetic data. A small eutrophic lake in the eastern section of the Holstein Lake District (350 ha, 9.5 m mean water depth) was chosen as the test biotope. Emptying into the lake was the runoff of a biological water treatment plant with 12,000 population equivalents and without notable business and industry. In a rectangular investigation area at first with 30 sampling stations positioned close to the outlet of the water treatment plant into the lake, kinetic tests were carried out in 48 hour intervals and then compared with bacteriological, chemical and meteorological sample results taken at the same time. Two typical result-blocks are illustrated (Fig. 1-4, 5-8). The first shows four successive test days with periodically strong wind and light to fairly strong but short periods of precipitation. The second block illustrates conditions during a following period of fair weather with only very light wind intensities. The corresponding conditions of the stratification of the drainage water in the investigation area are illustrated by the distribution of coliform organisms. In two other tables the kinetic parameters and individual, dominant data are contrasted numerically...

Bacteria↗
PubMed1990

Replacement of isoleucine-397 by threonine in the clotting proteinase factor IXa (Los Angeles and Long Beach variants) affects macromolecular catalysis but not L-tosylarginine methyl ester hydrolysis. Lack of correlation between the ox brain prothrombin time and the mutation site in the variant proteins.

Previously, from the plasma of unrelated haemophilia-B patients, we isolated two non-functional Factor IX variants, namely Los Angeles (IXLA) and Long Beach (IXLB). Both variants could be cleaved to yield Factor IXa-like molecules, but were defective in catalysing the cleavage of Factor X (macromolecular substrate) and in binding to antithrombin III (macromolecular inhibitor). In the present study we have identified the mutation of IXLA by amplifying the exons (including flanking regions) as well as the 5' end of the gene by polymerase-chain-reaction (PCR) method and sequencing the amplified DNA by the dideoxy chain-termination method. Comparison of the normal IX and IXLA sequences revealed only one base substitution (T----C) in exon VIII of IXLA, with a predicted replacement of Ile-397 to Thr in the mature protein. This mutation is the same as found recently for IXLB. The observation that IXLB and IXLA have the same mutation is an unexpected finding, since, on the basis of their ox brain prothrombin time (PT, a test that measures the ability of the variant Factor IX molecules to inhibit the activation of Factor X by Factor VIIa-tissue factor complex), these variants have been classified into two different groups and were thought to be genetically different. Our observation thus suggests that the ox brain PT does not reflect the locus of mutation in the coding region of the variant molecules. However, our analysis suggests that the ox brain PT is related to Factor IX antigen concentration in the patient's plasma. Importantly, although the mutation in IXLA or IXLB protein is in the catalytic domain, purified IXaLA and IXaLB hydrolyse L-tosylarginine methyl ester at rates very similar to that of normal IXa. These data, in conjunction with our recent data on Factor IXBm Lake Elsinore (Ala-390----Val mutant), strengthen a conclusion that the peptide region containing residues 390-397 of normal Factor IXa plays an essential role in macromolecular substrate catalysis and inhibitor binding. However, the two mutations noted thus far in this region do not distort S1 binding site in the Factor IXa enzyme.

Animals↗
PubMed1985

The financial impact of a comprehensive adolescent pregnancy program on a university hospital.

This study investigated the financial impact which an adolescent pregnancy program had on one of its sponsoring agencies, the University Hospital, Salt Lake City, UT. Financial data from hospital billings and collections on the 75 teens who delivered during a 12-month period were reviewed. A comparison of the money for salaries supplied to the special program by the hospital with the amount of estimated "new" money generated for the hospital by the program yielded an income to expenditure ratio greater than two. Eighteen teens who were in the lowest self-pay category were matched to self-pay teens delivering at the same hospital who received traditional prenatal care. The hospital collection rate for teens in the special program was not significantly greater than that of the comparison group. The investment in an adolescent pregnancy program was beneficial mainly from the viewpoint of recruitment of patients who were brought into the hospital system as a result of the adolescent pregnancy program.

Accounting↗
PubMed1991

Radioactivity in the Great Lakes.

Studies of radioactivity in the Laurentian Great Lakes are reviewed to evaluate the impact of radionuclide dissemination on the world's foremost freshwater aquatic ecosystem. The status of radiologically-degraded areas is also reported. Significant amounts of radioactivity are stored in the basin, which has numerous nuclear reactors as well as uranium mine waste areas. The prevailing low levels of artificially-produced radionuclides, arising largely from previous fallout inputs, provide very little radiation dose to the area residents consuming lake water. The interlake transport of radionuclides is adequately described by existing models, though some refinement of the source term is needed. Revised estimates of fallout over each lake are given, but no data are available to estimate drainage basin contributions. Only limited information is available on the dispersal of radioactive pollutants. The influence of chemical parameters on radionuclide cycling has been extensively investigated in Lake Michigan and, to a lesser degree, in Lake Ontario. The need for developing a radiological objective for fish becomes apparent from an assessment of the very few data collected thus far on the biological and dosimetric aspects. Several research and monitoring needs are also identified.

Canada↗
PubMedDate not supplied

[Fractionation of stable sulfur isotopes during microbiological processes in Slavyansk lakes].

The isotopic content of sulphur in sulphates increases with depth in waters containing hydrogen sulphide of the meromictic lakes Repnoe and Veisovo as a result of microbiological reduction of sulphates. At the same time, hydrogen sulphide enrichments 19 to 25% of the light isotope 32S in the lake Veisovo, and 24 to 32% in the lake Repnoe. The fractionation of sulphur isotopes, manifested in the enrichment of sulphides with lighter isotopes, and that of sulphates with heavier isotopes, was found also in the bottom deposits of the lake Repnoe. The isotope and microbiological data suggest that, in the zone of mass growth of the phototrophic sulphur bacteria in the lake Repnoe, there are two processes of fractionation: (a) due to the bacterial reduction of sulphates; and (b) due to anaerobic oxidation of hydrogen sulphide, resulting in the enrichment of hydrogen sulphide with the light isotope 32S by 5 to 7 promille.

Bacteria↗
PubMed1988

A study of vital and health statistics of the Kainji Lake Area of Nigeria.

A survey of vital and health statistics, and the evaluation of collection of these data in the registration centres of Kainji Lake Area, are presented. Forty-two per cent of all deaths occurred below 10 years of age, with the largest percentage occurring below 5 years of age. The leading causes of all deaths were malaria, gastro-intestinal disorders and measles. Occurrence of an epidemic was found to be significant to the overall mortality. The role of traditional healers in the control of childhood mortality is discussed. About 34% of the women had married more than once and 56% of the divorces occurred after the first marriage. The causes of divorces were largely due to loss of affection and neglect. The number of deliveries in the hospitals was more than the number of registered births and no death was registered at the centres. A unique system of collection of vital information was suggested for the Kainji Lake Area.

Adolescent↗
PubMed1979

A communication on health and development in the Kainji Lake area of Nigeria.

A study of the health care delivery facilities in the Kainji Lake area of Nigeria (an artificial lake created in 1968) showed that hospitals, a health centre, maternal and child health centres, public health units, dispensaries and leper institutions, controlled by various organizations, are available. Dispensaries and leper settlements/clinics form the most numerous health providers in the rural areas. Analysis of 1973 data from eight dispensaries around Lake Kainji showed that malaria, gastroenteritis, chest and skin infections, venereal diseases and shistosomiasis constitute the major health problems. Observations of the environmental sanitation in the study area by the author support the idea that the diseases emanate particularly from the low standard of environmental health. A suggestion is made for the establishment of a central organization charged with the responsibilities for health planning and development. The evaluation of the impact of hte dispensaries as health providers is needed for future health planning. A health care delivery system supported by operational research should be initiated at the village level.

Delivery of Health Care↗
PubMed1976

Isolation and identification of polychlorinated styrenes in Great Lakes fish.

Octachlorostyrene was prepared by two independent synthetic routes, and GC retention time data as well as a mass spectrum of the standard were obtained. A comparison of these data with those observed for a component in fish from Lake Huron, Lake Ontario, and the lower Detroit River indicates that octachlorostyrene is present in fish residues from these sources. In addition, mass spectral data indicated the presence of several hepta and hexachlorostyrene isomers in these fish. Further studies should be concerned with quantification of OCS and evaluation of possible sources of these compounds, such as impurities in products produced by exhaustive chlorination or as by-products in the electrolytic production of chlorine.

Animals↗