SEARCH · Search PubMed

Results for “data lake”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources

PubMed2005

Winter-time climatic control on dissolved organic carbon export and surface water chemistry in an Adirondack forested watershed.

Although most of forested watersheds in temperate and boreal regions are snow-covered for a substantial portion of the year, responses of biogeochemical processes under the snow pack to climatic fluctuations are poorly understood. We investigated responses of dissolved organic carbon (DOC) and surface water chemistry in stream and lake discharge waters draining the Arbutus Lake Watershed in the Adirondacks of New York State to climatic fluctuations during the snow-covered months from December through April. Interannual variability in stream discharge corresponded to changes in air temperature and snow pack depth across the winter months. Concentrations of DOC in stream water draining a subcatchment showed immediate positive responses to rising temperatures and subsequent increases in runoff during most snowmelt events. Increases in DOC concentrations usually coincided with decreases in pH and increases in total aluminum (Al) concentrations, while the correlations between concentrations of DOC and SO4(2-) or base cations were negative. Although changes in air temperature, snow pack depth, and runoff were all significantly correlated with stream water concentrations of major solutes, stepwise linear regression found that runoff was the best predictor of solute concentrations. Results of stepwise linear regression with long-term monthly monitoring data collected at the lake outlet showed weaker but still consistent climatic effects on interannual variations in concentrations of DOC and other solutes. Over the 17 winter periods from December 1983 through April 2000, changes in seasonal average concentrations of DOC, H+, and Al in lake discharge generally corresponded to interannual variations in temperature, precipitation, and runoff, while SO4(2-) and base cations displayed an opposite trend. The results suggest that snowmelt-mediated DOC responses to temperature fluctuations during the winter months might offset increases in the surface water pH caused by decreasing acidic deposition and pose a potential hazard of Al toxicity in surface waters.

Air↗

PubMed2004

Exposure assessment and initial intervention regarding fish consumption of tribal members of the Upper Great Lakes Region in the United States.

The Ojibwe Health Study (OHS) has concluded 10 years of data collection and exposure assessment. Eight hundred and twenty-two participants from tribes in the states of Wisconsin, Michigan, and Minnesota (USA) completed fish consumption and environmental risk perception questionnaires. Many participants provided hair and blood samples for mercury and polychlorinated biphenyl (PCB) residue analyses as body burden indicators of these persistent environmental pollutants. Fish were collected by the tribal organizations and contaminants were analyzed for numerous tribal reports and professional environmental journal articles, these data were used by the Great Lakes Indian Fish and Wildlife Commission to produce tribal-specific geographic information systems maps as part of a public health intervention strategy. These maps are currently available at for six Wisconsin tribes that regularly harvest walleye. To determine the health impacts (if any) of pollutants on cancer, diabetes, and reproduction, it was necessary to know the recent trends in key indicators such as cancer mortality ratios and birth gender ratios. The Great Lakes Inter-Tribal Council provided the OHS and each participating tribe in Wisconsin and Michigan with a health profile. Total fish consumption (estimated by recall) for 720 tribal participants was self-reported as 60 g/day, but the highest actual consumption was measured as 11.2 g/day in one of the tribal groups. The highest blood concentrations in tribal participants were 18.6 ppb total serum PCBs and 11.8 ppb total blood mercury. Ninety percent of the participants had less than 3.8 ppb total serum PCBs and 2.6 ppb total blood mercury. Compared to other studies of subsistence fishing populations, these exposures were only moderately elevated and not high enough to warrant widespread restrictions on diets. Furthermore, the benefits of eating a fish diet must be continually emphasized. However, sport fishermen and their families who consume larger and more contaminated fish should abide by their state fish consumption advisories to minimize their health risks.

Adult↗

PubMed2001

Zooplankton of subarctic Imandra Lake following water quality improvements, Kola Peninsula, Russia.

The composition, species richness and abundance of zooplankton communities were studied in two highly contaminated areas: (1) mainly by heavy metals and other toxic and non-toxic matter, and (2) mainly by fine particles of nepheline and other minerals and organic matter, in the large, subarctic Imandra Lake (northwestern Russia), based on data collected between 1978 and 1990. Reduction in the relative abundance of the typical inhabitants of northern oligotrophic lakes and their substitution by tolerant-to-pollution, widely distributed, circumpolar species were the general trends for the communities. In both lake areas, water quality changes occurred in response to reductions in contamination of metals, mineral particles and organic matter in the mid 1980s. Water chemistry improvements, including decreased concentrations of pollutants, have resulted in partial recovery of zooplankton communities, increase in species richness, density of individuals, and shifts in composition of the dominance group. However, both lake areas are still contaminated and re-establishment of communities typical of a non-polluted lake did not occur between the mid 1980s and mid 1990s.

Animals↗

PubMed2006

Geoacoustic inversion of short range source data using a plane wave reflection coefficient approach.

Acoustic time series data were collected in a shallow, hard bottom lake environment located in central Texas using both short range (2 m) implosive data, obtained with the source and a single hydrophone located near mid-depth in the waveguide, along with longer range implosive and explosive data from a near surface source to a bottom mounted hydrophone. Matched field inversions using simulated annealing were performed with a ray trace plus complex plane wave reflection coefficient forward propagation model that was validated in previous work. Isolating bottom interacting paths to perform the inversions is shown to be essential to reduce parameter uncertainties in the hard bottom environment and enables a systematic approach to the inversions which establishes the number of layers needed to represent the lake environment. Measured transmission loss data from a towed source were compared through a RMS error analysis to modeled transmission loss, constructed with the parameters from inversions of data from several source types, to further establish the validity of the inversion approach for this environment. Geoacoustic parameters obtained by inversions of short range, low frequency impulsive data are used to predict transmission loss at longer ranges and higher frequencies. The range dependence of the global minimum is discussed.

Acoustics↗

PubMed2003

Groundwater quality surrounding Lake Texoma during short-term drought conditions.

Water quality data from 55 monitoring wells during drought conditions surrounding Lake Texoma, located on the border of Oklahoma and Texas, was compared to assess the influence of drought on groundwater quality. During the drought month of October, water table levels were three feet (0.9 m) lower compared with several months earlier under predrought climate conditions. Detection frequencies of nitrate (> 0.1 mg/l), orthophosphates (> 0.1 mg/l), chlorides (> MCL), and sulfates (> MCL) all increased during drought. Orthophosphate level was higher during drought. Largest increases in concentration were nitrate under both agriculture lands and in septic tank areas. An increase in ammonium-nitrogen was only detected in the septic tank area. The study showed that stressors such as nitrate and total salts could potentially become a health or environmental problem during drought.

Disasters↗

PubMed2001

Theoretical framework for the distribution of trace metals among the operationally defined speciation phases of a sediment.

The use of a model based on Langmuir's isotherm to evaluate the metal associated with separate geochemical phases of a sediment is proposed and its validity tested with sediments of certified composition. The model takes into account a standard procedure for a certified reference material (CRM601), which defines, experimentally, a set of sequential extractions that divide the sediment into four operational fractions. The derived equations allow the treatment of data from sediment of Flumendosa Lake, Italy, and certified material CRM601 and also allow the computation of corrected concentrations, i.e., the metal affinities for each fraction. Experimental values for Ni show its low sensitivity and an equal distribution among different phases, which suggests a similar adsorption mechanism in all cases. In the case of Cd, the corrected concentration in the Fe/Mn oxide phase is nine times higher than for the residual fraction. For sediment of the Bèsos River, Spain, results show the percentage distribution of Ni over different fractions. Affinity values for Ni on a Flumendosa Lake sediment have also been calculated. The present model is simple to apply and shows satisfactory agreement with experimental data.

Geologic Sediments↗

PubMedDate not supplied

Bi-national assessment of the Great Lakes: SOLEC partnerships.

Many administrative jurisdictions have authority over parts of the Great Lakes, sometimes with competing purposes as well as governance at differing scales of time and space. As demand increases for high quality information that is relevant to environmental managers, environmental and natural resource agencies with limited budgets must look to interdisciplinary, collaborative approaches for the collection, analysis and reporting of data. The State of the Lakes Ecosystem Conferences (SOLEC) were begun in 1994 in response to reporting requirements of the Great Lakes Water Quality Agreement between Canada and the U.S. The biennial conferences provide independent, science-based reporting on the state of health of the Great Lakes ecosystem components. A suite of indicators necessary and sufficient to assess Great Lakes ecosystem status was introduced in 1998. and assessments based on a subset of the indicators were presented in 2000. Because SOLEC is a multi-agency, multi-jurisdictional reporting venue, the SOLEC indicators require acceptance by a broad spectrum of stakeholders in the Great Lakes basin. The SOLEC indicators list is expected to provide the basis for government agencies and other organizations to collaborate more effectively and to allocate resources to data collection, evaluation and reporting on the state of the Great Lakes basin ecosystem.

Canada↗

PubMed2002

Dissipation of triclopyr herbicide applied in Lake Minnetonka, MN concurrently with Rhodamine WT dye.

Fluorescent dye was applied concurrently with triclopyr in two 6.5-ha treatment plots in Lake Minnetonka, MN for data collection to support full aquatic registration of this herbicide. The herbicide and dye mixture was applied by airboat to Phelps Bay with weighted, trailing hoses to maximize uniform distribution of these materials in the water column. A surface application was made to the Carsons Bay plot to attain theoretical triclopyr and dye concentrations of 2500 and 10 micrograms litre-1, respectively. Water samples collected at various times following application showed very little movement of the herbicide and dye out of the Carsons Bay plot. Triclopyr residues moved to a greater extent out of the Phelps Bay plot. The dye was easily tracked in real-time using field fluorometers, which allowed new sampling stations to be established to monitor this movement. Dye concentrations were strongly correlated to herbicide concentrations (r2 = 0.97 in both plots) but were less predictive of the triclopyr metabolite 3,5,6-trichloropyridinol (TCP; r2 = 0.82 in Phelps and r2 = 0.73 in Carsons), probably due to its differential metabolism and degradation. The inert dye can be used to compare the dissipation of herbicide residues by dilution versus microbial or other breakdown processes. Vertical sampling of dye in the water column showed that surface applications of aquatic herbicides can delay uniform mixing in the water column by several days. Although the dye aided the tracking of residues outside the treatment areas, predetermined sampling times and stations were still needed if very low concentrations of herbicide were to be detected at times and stations where the dye had been diluted below its limit of detection.

Biodegradation, Environmental↗

PubMed2006

Latitudinal gradients in niche breadth and position-regional patterns in freshwater fish.

The latitudinal gradient in diversity is widely acknowledged, but the mechanisms contributing to this pattern are still poorly known. Given that the species have environmental optima, a central issue is how species' niche parameters, i.e. niche breadth and niche position, vary along the latitudinal gradient. In this study, we examined the determinants of fish distribution and the variability in species' niche breadth and position along latitudinal gradient using a regional data set of boreal lakes. Results of the Outlying Mean Index analysis showed that the fish community structure was jointly controlled by a number of environmental factors, ranging from water chemistry and temperature to local physical factors such as lake area and depth. Corroborating the number of earlier findings, the regional occupancy of species was more strongly governed by the niche position than the niche breadth, although both showed a significant relationship with the regional distribution. When the latitudinal variability in niche parameters of the main taxonomic groups was analysed, both percids and cyprinids, being cool water species, showed significant decrease in niche breadth northwards as we predicted. By contrast, the niche position and latitude were non-significantly correlated in percids and salmonids, and negatively correlated in cyprinids, the latter showing the opposite pattern as we predicted. However, even if only a part of our predictions was supported, the results generally implied that the examination of latitudinal variability in the niche properties is potentially highly rewarding, not only in estimation of present community structure in lakes but also for predictions of species' responses to climate change.

Animals↗

PubMed2006

A critical analysis of Illinois' fish mercury monitoring program, 1974-1998.

Mercury contamination in fish is a serious public health concern that contrasts with other health benefits of eating fish. Like most US states, Illinois has monitored fish mercury contamination for decades to warn the public of mercury exposure risks by consuming fish. Has this monitoring program been effective in detecting public mercury exposure risks? I analyzed fish mercury contamination data from Illinois inland lakes (1974-1998; > 2,300 samples, 18 fish species, 149 lakes) and found that: (a) sampling and analyses have been severely limited since 1985; (b) sampling effort varied widely among lakes and species, and (c) trends and spatial patterns were confused by this variability. As a result of a severely limited and nonstrategic monitoring program, public mercury exposure risks via Illinois fish consumption remain unclear, despite much effort over many years. Illinois monitors fewer fish per angler than many US states, but is not alone in this regard. Illinois should resurrect and redesign its fish contaminant monitoring program to one that strategically and systematically assesses human mercury exposure risk. Other US states and nations may also benefit from similar retrospective examinations of monitoring programs intended to protect public health.

Animals↗

PubMed2004

Synthesis, isolation, and GC analysis of all the 6,8- to 13,15-cis/trans conjugated linoleic acid isomers.

Octadecadienoic acids with conjugated double bonds are often referred to as conjugated linoleic acid, or CLA. CLA is of considerable interest because of potentially beneficial effects reported from animal studies. Analysis of CLA is usually carried out by GC elution of FAME. If the presence of low-level isomers is of interest, a complementary technique such as silverion HPLC is also used. These analyses have been hindered by a lack of well-characterized commercially available reference materials. Described here are the synthesis and isolation of selected 6,8- through 13,15-positional CLA isomers, followed by isomerization of these CLA isomers with iodine to produce all the possible cis,cis, cis,trans, trans,cis, and trans,trans combinations. Also present are the GC retention times of the CLA FAME relative to gamma-linolenic acid (6c,9c,12c-octadecatrienoic acid) FAME using a 100-m CP Sil-88 capillary column (Varian Inc., Lake Forest, CA). These data include all the CLA isomers that have been identified thus far in foods and dietary supplements and should greatly aid in the future analysis of CLA in these products.

Chromatography, High Pressure Liquid↗

PubMed2005

The United Kingdom Acid Waters Monitoring Network: a review of the first 15 years and introduction to the special issue.

The United Kingdom Acid Waters Monitoring Network (AWMN) was established in 1988 to determine the ecological impact of acidic emissions control policy on acid-sensitive lakes and streams. AWMN data have been used to explore a range of causal linkages necessary to connect changes in emissions to chemical and, ultimately, biological recovery. Regional scale reductions in sulphur (S) deposition have been found to have had an immediate influence on surface water chemistry, including increases in acid neutralising capacity, pH and alkalinity and declines in aluminium toxicity. These in turn can be linked to changes in the aquatic biota which are consistent with "recovery" responses. A continuation of the current programme is essential in order to better understand apparent non-linearity between nitrogen (N) in deposition and runoff, the substantial rise in organic acid concentrations, and the likely impacts of forecast climate change and other potential constraints on further biological improvement.

Acid Rain↗

PubMed1999

The fate of metals in Arctic surface waters. Method for defining critical levels.

Based upon studies in the industrially developed Arctic region, Russian Kola, here we discuss the fate of metals in high latitude surface water. Mainly, attention is paid to the priority pollutants from copper-nickel smelters. The influence of accompanying processes, such as acidification and eutrophication, on metal behavior is considered. The dramatic situation for fauna of Arctic latitudes is illustrated: (i) during the snow-melt, due to the pulse of ionic metal forms; and (ii) during the long polar winter in lower water layers, due to the involvement of a wide spectrum of metals in the redox-cycle under eutrophication and oxygen deficiency. Here we identify fish pathologies, which are related to the influence of metals. Generalizing the data on metal behavior, an original approach to define the integrated impact dose of metals--a toxicity index--has been developed. It presents a visualization of the integrated toxicity index for surface waters of the Russian Kola (based on the data for a 460-lake survey). As shown, there is a risk of fish diseases, due to both airborne contamination by metals and an indirect leaching by acid runoff over almost 30% of the area of the Russian Kola. For the Arctic region, polar winter stress syndrome will be repeatedly significant. During the polar night, as well as the spring, the vulnerability of the Arctic biota to toxic impact is higher. The accompaniment of water metal-pollution by two or more stressors would occur simultaneously, thereby multiplying the risk that it could develop.

Acid Rain↗

PubMed2000

Topography-driven photorefractive keratectomy: results of corneal interactive programmed topographic ablation software.

OBJECTIVE: This study evaluated the efficacy, predictability, stability, and safety of a software program (Corneal Interactive Programmed Topographic Ablation (CIPTA) LIGI, Taranto, Italy) which, by transferring programmed ablation from the corneal topography to a flying-spot excimer laser, provides customized laser ablation. DESIGN: Noncomparative consecutive case series. PARTICIPANTS: Forty-two eyes of 34 subjects with a mean age of 33.9 (range, 20-54) had CIPTA at the Cattedra di Ottica Fisiopatologica of Bari (Italy). Twenty-eight eyes were treated for hyperopic astigmatism and 14 for myopic astigmatism. All the subjects had irregular astigmatism. OPERATION: Topography was acquired by a corneal topography mapping system (Orbscan, Orbtek, Inc., Salt Lake City, UT). These data were processed to obtain a customized altimetric ablation profile, which was transferred to a flying-spot laser (Laserscan 2000, Lasersight, Orlando, FL). MAIN OUTCOME MEASURES: Data on uncorrected (UCVA) and best-corrected visual acuity (BCVA), predictability, and stability of refraction and any complications were analyzed. RESULTS: Mean follow-up was 13.2 months. At the last postoperative examination, 26 eyes (92.8%) in the hyperopic group and 12 eyes (85.7%) in the myopic group had an UCVA superior to 20/40. Twelve hyperopic eyes (42.8%) and five myopic eyes (35.7%) had a UCVA of 20/20. All patients fell between 1 diopter of attempted correction in the spherical equivalent. Only 1 (2.4%) of the 42 eyes, belonging to the hyperopic group, lost 1 Snellen line of BCVA. We did not observe any decentration and/or haze after photorefractive keratectomy treatment or any irregularity in the flap-stroma interface in the three laser in situ keratomileusis operations performed in this study. CONCLUSIONS: The combination of topographic data with computer-controlled flying-spot excimer laser ablation is a suitable solution for correcting irregular astigmatism due to different causes.

Adult↗

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↗

PubMed2005

Development of an ecosystem sensitivity model regarding mercury levels in fish using a preference modeling methodology: application to the Canadian boreal system.

The objective of this study is to use a preference modeling methodology as a predictive tool to roughly assess the sensitivity of the ecosystems regarding mercury (Hg) concentrations in fish. We apply a preference modeling methodology to rank lakes within the boreal forest from highest to lowest Hg concentrations in fish using simple environmental factors. Among the numerous variables influencing Hg fate in the environment, we only retain simple key indicators that are expected to influence Hg concentrations in fish tissue such as watershed characteristics of the lake (percentage of the catchment area of the lake, ratio of drainage area versus lake area, percentage of the drainage area of the lake as wetlands, land use, and clear-cutting), lake characteristics (chlorophyll, dissolved organic carbon, pH, and fishing intensity), and atmospheric Hg inputs. Preliminary results of modeling that we carried out using a set of Canadian lakes of boreal forest data are promising. With only a minimum set of criteria, we are able to reproduce the trends of Hg contamination in fish caught in six regions of the Canadian boreal forest and classify the sensitivity of the ecosystems to Hg loadings in three categories: high, medium, and low.

Animals↗

PubMed2006

Ozone concentrations in the Central Wasatch Mountains of Utah.

In the Salt Lake Valley, a June through August SUM60 value (sum of hourly average ozone concentrations > or =60 parts per billion by volume [ppbv]) of 25,000 ppbv-hr was exceeded in 9 yr between 1978 and 1998. Ozone concentrations in the nearby Central Wasatch Mountains were monitored to determine the potential for vegetation injury. The SUM60 value of 19,000 ppbv-hr in these mountains and peak hourly concentrations >100 ppbv suggests that ozone-sensitive species may be injured. Ozone concentrations in the mountains were greatest during periods of strong upslope winds from the Salt Lake Valley. Both SUM60 values and hourly average concentrations in the Central Wasatch Mountains were strongly correlated with those in the Salt Lake Valley, suggesting that data from valley stations could be used to estimate ozone in the mountains.

Air Pollutants↗

PubMedDate not supplied

Derivation of emergency medical services dispatch codes associated with low-acuity patients.

OBJECTIVE: To identify emergency medical services (EMS) dispatch codes associated with basic life support (BLS) level of prehospital care, a proxy for low illness acuity. METHODS: This retrospective cohort study was conducted in an urban city with a single advanced life support level EMS provider. The 911 center was certified in using dispatch protocols from Priority Dispatch Corporation (Salt Lake City, UT). Dispatch data on all transported EMS patients from August 2001 to April 2002 were abstracted. The authors prospectively defined a low-acuity patient as one who received BLS-level care and defined a low-acuity dispatch code as one in which at least 90% of coded patients required only BLS care. For each dispatch code or code group, the authors calculated the fraction of patients who received BLS-level care. For each "A"-level (lowest category) dispatch code group, the fraction of patients receiving BLS-level care was also evaluated. RESULTS: A total of 19,332 calls met inclusion criteria and were categorized into 118 dispatch codes or code groups. Twenty-eight codes or code groups with 7,801 patients met the authors' definition of low acuity. Overall, 7,394 patients received only BLS care (94.8%, 95% confidence interval: 94.3%-95.3%). Analysis of "A"-level dispatch code groups found BLS use rates of 52.8% to 99.3%. CONCLUSIONS: Certain dispatch codes are associated with the delivery of BLS-level care, indicating identification of patients likely to be low acuity. These codes are not necessarily "A"-level dispatch codes, which are commonly considered to represent the lowest-acuity patients. Future studies are needed to prospectively validate that these codes do represent low-acuity patients.

Acute Disease↗