bluuebunny/crossref_metadata_2025_split huggingface dataset:
Putting the ‘Human’ Back in Genetics: Modeling the Extended Kinships of Twins
Authors: Eaves Lindon 
Published: February 2009

AbstractFew papers have attempted to address the potential of extended kinships of twins to resolve the complexities of biological and cultural inheritance in humans. Since the mid-80s these issues have largely been buried beneath the quest for specific genes that contribute to individual differences in complex traits and liability to disease. The articles of Keller et al. and Medland and Keller (current issue) revisit these issues. History will decide whether these new papers represent the final gasp of a paradigm superceded by the ‘new’ genetics or contain the timely seeds of new birth in the face of a 30-year genetic research program otherwise poised on the cusp of degeneration (Lakatos & Musgrave, 1970).
Effects of 32-Year Leisure Time Physical Activity Discordance in Twin Pairs on Health (TWINACTIVE Study): Aims, Design and Results for Physical Fitness
Authors: Leskinen Tuija , Waller Katja , Mutikainen Sara , Aaltonen Sari , Ronkainen Paula H. A. , Alén Markku , Sipilä Sarianna , Kovanen Vuokko , Perhonen Merja , Pietiläinen Kirsi H , Cheng Sulin , Suominen Harri , Kainulainen Heikki , Kaprio Jaakko , Kujala Urho M 
Published: February 2009

AbstractThe physically active lifestyle is associated with low future morbidity and mortality, but the causality between physical activity and health is not always clear. As some inherited biological characteristics and childhood experiences may cause selection bias in observational studies, we sought to take them into account by identifying 16 twin pairs (7 MZ, 9 DZ, mean age 60 years) discordant for leisure time physical activity habits for thirty years. We conducted detailed health-related examinations among these twin pairs. Our main aims were to study the effects of physical activity and genes on fitness and body composition, with special reference to body fat compartments, metabolic syndrome components and related diseases and risk factor levels, status of arteries, structure and function of the heart, bone properties, and muscle and fat tissue-related mechanisms linked to physical activity and chronic disease development. Our physical activity assessments showed that inactive co-twins were on average 8.8 MET hours/day less active than their active co-twins through out their midlife (2.2 ± 2.3 vs. 11.0 ± 4.1 MET h/day, p < .001). Follow-up fitness tests showed that physically inactive co-twins were less fit than their active co-twins (estimated VO2peak 26.4 ± 4.9 vs. 32.5 ± 5.5 ml/kg/min, p < .001). Similar differences were found in both MZ and DZ pairs. On the basis of earlier epidemiological observations on nonrelated individuals, these physical activity and fitness differences are large enough to cause differences in many mechanisms and risk factors related to the development of chronic diseases and to permit future analyses.
Comparisons of Refractive Errors Between Twins and Singletons in Chinese School-Age Samples
Authors: Hur Yoon-Mi , Zheng Yingfeng , Huang Wenyong , Ding Xiaohu , He Mingguang 
Published: February 2009

AbstractStudies have reported that refractive errors are associated with premature births. As twins have higher prevalence of prematurity than singletons, it is important to assess similarity of the prevalence of refractive errors in twins and singletons for proper interpretations and generalizations of the findings from twin studies. We compared refractive errors and diopter hours between 561 pairs of twins and 3757 singletons who are representative of school-age children (7–15 years) residing in an urban area of southern China. We found that the means and variances of the continuous measurement of spherical equivalent refractive error and diopter hours were not significantly different between twins and singletons. Although the prevalence of myopia was comparable between twins and singletons, that of hyperopia and astigmatism was slightly but significantly higher in twins than in singletons. These results are inconsistent with those of adult studies that showed no differences in refractive errors between twins and singletons. Given that the sample size of twins is relatively small and that this study is the first to demonstrate minor differences in refractive errors between twins and singletons, future replications are necessary to determine whether the slightly higher prevalence of refractive errors in twins than in singletons found in this study was due to a sampling error or to the developmental delay often observed in twins in childhood.
Effect of the Mud-Water Interface on the Chemical Life of Lakes
Authors: Cowgill UM 
Published: February 2009

There is scant information concerning the chemical composition of the mud-water interface in shallow, aerobic, eutrophic bodies of water. A little more is known of this region in deep eutrophic lakes with periodically anaerobic hypolimnions. The object of this paper is to compare the composition of the mud-water interface in two such limnological systems and to demonstrate the effect this region exerts on the chemical life of lakes.
The shallow lake used as an example is the preserve of Lake Huleh, Israel, which is hypereutrophic and rarely contains water to a depth greater than 35 cm but has an area of 46.9 ha (116 acres). Linsley Pond, Connecticut, will be used as an example of a deeper (14.6 m) eutrophic lake which is thermally stratified except for the autumnal and vernal isothermal periods.
In a shallow aerobic pond such as the Huleh Preserve, elements that are sorbed by the mud fall into two groups: those that are sorbed and retained by the organic matter, and those that move in concert with the ferric hydroxide complex. Under anaerobic conditions such as those present in Linsley Pond much of the year, those same elements diffuse from the mud into the hypolimnion.
Those elements held most strongly in the surface waters, as contrasted to the mud-water interface in shallow aerobic systems such as the Huleh Preserve, diffuse from the reduced mud surface in anaerobic systems such as Linsley Pond.
Some elements diffuse from a reduced mud surface and under aerobic conditions attain equilibrium. These are rubidium, lithium, and aluminum.
Sodium, boron, silicon, chromium, nickel, and chlorine do not diffuse from a reduced mud surface. In aerobic systems chlorine attains equilibrium, while in the shallow Huleh Preserve the sodium concentrates in the surface water. Boron, silicon, chromium, and nickel in shallow systems become enriched in surface waters in contrast to the liquid or solid portion of the mud-water interface.
All elemental concentrations reported in this study represent the total amount detected. Speciation is not addressed. The cyclical nature of elemental concentrations noted in this study should provide a much-needed background for sediment quality criteria.
Long-Term Multispecies Toxicity and Effluent Fractionation Study at a Municipal Wastewater Treatment Plant
Authors: Goodfellow WL , McCulloch WL , Botts JA , McDearmon AG , Bishop DF 
Published: February 2009

Characterization of the acute and chronic toxicity of effluent samples from the Patapsco Wastewater Treatment Plant (WWTP), Baltimore, Maryland, was performed approximately twice weekly from April 1986 to January 1987. Acute toxicity of both the primary and secondary effluents was evaluated using Ceriodaphnia dubia, Mysidopsis bahia, and Microtox [a luminescent marine bacteria Photobacterium phosphoreum (Beckman Instruments, Inc.)]; chronic toxicity was evaluated using the C. dubia seven-day chronic test. The data indicate that C. dubia was the most sensitive indicator of acute toxicity for both primary and secondary effluent wastewaters. The acute responses for M. bahia and Microtox were considerably less sensitive than those for C. dubia. The 48-h median lethal concentration (LC50) values for C. dubia ranged from 0.5 to 23.4% secondary effluent and 0.1 to 6.5% primary effluent wastewaters. Microtox 5-min median effective concentration (EC50) values ranged from 9.4 to 100% secondary effluent and 0.6 to 19.5% primary effluent, respectively. M. bahia 96-h LC50 values were 8.9 to 100% secondary effluent and 14.8 to 35.4% primary effluent, respectively. The seven-day C. dubia chronic values (ChV) for the primary and secondary effluents were only slightly lower than the acute responses, ranging from &lt;0.1 to 9.4% secondary effluent and &lt;0.1 to 6.5% primary effluent, respectively.
As an additional characterization of the plant's treatment process effectiveness, influent and effluent samples were fractionated in an attempt to identify specific components of acute toxicity entering and leaving the WWTP. As a result of the fractionation study, nonpolar organic compounds appeared to be the major toxic component of the samples fractionated. While identification of the specific compounds causing toxicity in the nonpolar organic fractions was not possible, the octanol/water partition coefficient (Log P) values for the most toxic fractions were estimated to be approximately 6 to 9 in the summer samples and approximately 3.6 to 8.3 in the winter samples. Cations, anions, and polar organic compounds do not appear to be major contributors to the toxicity of the effluent samples fractionated. The percentage of toxicity reduction across the plant was approximately 50 to 90% for the three species tested.
Comparison of Estimates of Effects of a Complex Effluent at Differing Levels of Biological Organization
Authors: Pratt JR , Mitchell J , Ayers R , Cairns J 
Published: February 2009

Impact of a toxic municipal sewage effluent containing textile dyes was evaluated using standard acute and chronic single-species tests and a microcosm test using indigenous microbiota from the receiving stream. Estimated effect levels were compared with the calculated in-stream waste concentration and measured impacts on stream microbiota and macrobenthos. Acute tests examined effluent effects on Daphnia pulex, and short-term chronic effluent dilution tests were conducted using Ceriodaphnia dubia and larval Pimephales promelas. Microcosm tests examined effluent effects on the structure and function of microbial communities on artificial substrates. Additional tests examined effects of receiving stream water on C. dubia and microcosms.
Effluent concentrations of 70% were acutely toxic in median effective concentrations) to D. pulex. Estimates of the no-observable-effect concentration (NOEC) were 10 and 7.5% for C. dubia and P. promelas, respectively. Responses in the microcosm systems were nonlinear and showed significant subsidy of both structure and function at concentrations of &gt;30% and toxicity at concentrations &gt;30%. Tests of receiving stream water below the effluent outfall showed a slight depression of reproduction in C. dubia and recovery to upstream levels for water sampled from farther downstream. Microcosms treated with ambient stream water did not show effects on taxonomic richness, but reduced midmorning oxygen levels were observed for microcosms dosed with water from stations below the effluent outfall. Surveys of in-stream microbiota and macrobenthos confirmed adverse impacts below the discharge and indicated recovery 11 km downstream. Microcosm tests were generally less sensitive than single-species tests in detecting toxicity of the effluent. None of the laboratory tests corresponded to observed in-stream effects. The sensitivity of the tests may have been improved by improving the test conditions, including continuous replacement of effluent, as was done in larval P. promelas tests. To be effective in predicting in-stream effects, the design of intensive toxicity surveys should make every effort to mimic local conditions.
Evaluation of Lethal Levels, Release Criteria, and Water Quality Objectives for an Acid-Mine Waste
Authors: Finlayson BJ , Wilson DC 
Published: February 2009

Acid-mine discharges from the Spring Creek drainage contribute large quantities of toxic copper, zinc, and cadmium to anadromous chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Salmo gairdneri) fisheries below Keswick Dam after regulated release with the Sacramento River, California. Release criteria and water quality objectives for the protection of salmonids from the metals in the waste have been developed using laboratory toxicity tests and field monitoring studies. These metal criteria and objectives were evaluated by on-site toxicity tests and additional monitoring studies.
Chinook salmon and steelhead trout fry were exposed to Spring Creek acid-mine waste in on-site toxicity tests. Acutely lethal concentrations of copper, zinc, and cadmium from the waste were similar to those from laboratory tests on metal sulfate mixtures, indicating that these metals are the major toxic components of the waste. Monitoring the waste in the Sacramento River after controlled dilution using criteria for copper and zinc indicated the following: (1) mean concentrations of the metals approached or exceeded incipient lethal levels (96-h LC10 values); (2) short-term (&lt;5 out of 24 h) peak concentrations of copper, zinc, and cadmium in the Sacramento River exceeded median lethal levels (96-h LC50 values) under normal operating conditions; and (3) no measurable loss of copper from adsorption onto particulate matter and subsequent precipitation and deposition occurred when the waste was diluted to levels tolerable to fish. New criteria for zinc and new release schedules for the copper criteria that will protect against acutely lethal levels should be developed.
Performance and Validation of an On-Line Fish Ventilatory Early Warning System
Authors: Gruber D , Diamond J , Johnson D 
Published: February 2009

A continuous, automated biological early warning system for rapidly detecting acutely toxic wastewater was developed and tested over a two-year period at an ammunition manufacturing plant. The computerized system simultaneously tracked and analyzed the ventilatory frequency of control and exposed bluegill (Lepomis macrochirus), generating either “warnings” or “alarms” depending on the toxicity of the exposure water. Standard acute flow-through toxicity tests (96 h) were concurrently performed on the wastewater to validate the results of the ventilatory system. Standard water quality and chemical monitoring were also performed during the study to interpret the results of the early warning system.
Several preliminary trials indicated that a data assessment interval of 10 min and a sampling rate of 60 Hz for each fish was generally sufficient for detecting acutely toxic conditions. Alarms (statistically significant changes in ventilatory rate over time) were usually generated within 30 min of exposure to effluent concentrations approximating the 96-h median lethal concentration (LC50) value. Time to alarm was inversely related to the toxicity (percentage of the LC50) of the effluent; longer times to alarm occurred with decreasing effluent toxicity (R2 = -0.88). The system was capable of detecting 10% of the 96-h LC50 concentration within 24 h. Less toxic effluent concentrations were not reliably detected with the present system.
Water quality and chemical monitoring data generally contributed little information in this study. A general lack of analytical sensitivity may have contributed to this finding. It was thought that better analytical sensitivity would have yielded stronger correlations between the chemical composition of the effluent and toxicity effects. Regression analyses indicated that 35% of the variability in the toxicity tests and ventilatory data was explained by the available chemical data.
Two general problems were evident in this system. First, ventilatory rate alone was occasionally an insufficient parameter for detecting acute toxicity. In several runs, ventilatory amplitude and waveform patterns were more informative response variables than frequency. Second, due to the insufficient information generated at times by frequency data alone, false alarms or lack of alarms were evident, reducing the reliability of the system. Results of this study confirm that fish ventilatory systems can serve as useful early warning tools for monitoring wastewaters and that all facets of ventilatory behavior need to be monitored to ensure system reliability. This study also shows that validation of early warning systems, through traditional toxicity tests and chemical monitoring, is crucial to the development of sound approaches for rapidly detecting toxics in surface waters.
Evaluation of the Intrinsic Rate of Increase as an Endpoint for Ceriodaphnia Chronic Tests
Authors: Barbour MT , Graves CG , McCulloch WL 
Published: February 2009

Fecundity and survival data can be used to calculate a number of demographic measures which characterize populations including net replacement rate, generation length, life xpectancy, and reproductive value. Another measure is r, lternately called the intrinsic or instantaneous rate of population increase. This statistic is a measure of the capacity of a population to increase in an unlimited environment and is in estimate of ecological growth potential. The equation of Lotka (1925) for calculating the intrinsic rate of increase is 1=∑x=0nlxmxe−rx Where n is the number of age classes, lx is the probability of survival from birth to Age Class x, and mx is the average number of births per individual in Age Class x.
The intrinsic rate of increase, r, has been calculated for &gt;50 chronic toxicity tests on effluents from publicly owned treatment works (POTWs), metal refinishers, and acid-mine drainage. The hypothesis was that the intrinsic rate of increase is a sensitive endpoint for estimating toxicity to populations exposed to toxicants in laboratory experiments. Results of analyses performed on seven-day Ceriodaphnia tests indicate that r is actually less sensitive than the other chronic endpoints examined for toxicity tests with limited observation days which serve as age classes. These results suggest that for the type of toxicity test examined (short-term chronic), the calculation of r does not add to the interpretation of toxic response that can be made from evaluating fecundity and survival data as separate measures. Although r is a useful chronic endpoint, it is not cost effective to calculate when simpler estimates of toxicity are available.
Sensitivity and Uncertainty Analyses for Use with Chemical Fate and Transport Models
Authors: Staples CA , Sebaugh JL 
Published: February 2009

A method for evaluating sensitivity and uncertainty analyses is presented here for use with chemical environmental exposure models. Sensitivity analysis allows one to assess the relationship between a set of potentially important model input variables and the model output. Uncertainty analysis allows one to assess the set of output values obtained and estimate various statistical properties such as the mean, median, standard deviation, and range. Absence of the ability to quantify parameter value uncertainty and model output uncertainty limits the validity of predictive model use. Use of the methods presented in this paper can increase the confidence in predictive environmental chemical fate model use.
The present investigation employed the Latin hypercube sampling method developed by Iman and Shortencarier at Sandia National Laboratories, Albuquerque, NM. It requires that a set of input variables be identified, and the probability distribution of each be specified. The range of each input variable is divided into intervals having equal probabilities, and one value is randomly selected from each interval. Sets of model input variables are then generated which cover the range of each variable. Some model inputs may then be calculated as functions of these key input variables. The computer model is run for each set of input variables and the model output is obtained.
Regression techniques can then be employed to examine the differential sensitivity of the model to the various input variables and functions thereof, for example, cross products of input variables. Since the model input values are chosen based on probabilities, the set of model outputs can also be interpreted on a probabilistic basis.
The techniques discussed in this paper respond to the growing need by chemical exposure model users for better defined sensitivity analysis procedures which can aid in explaining and interpreting results. An example problem data set is presented which highlights the methodological techniques and their utility.
Results of Interlaboratory Testing of the Standardized Aquatic Microcosm Protocol
Authors: Taub FB , Kindig AC , Conquest LL , Meador JP 
Published: February 2009

The “standardized aquatic microcosm” (SAM) protocol was performed by four laboratories, including the authors' laboratory, and the results of seven experiments are presented. Each laboratory tested the toxicant copper at three concentrations (500, 1000, and 2000 ppb) plus a control.Nitrate depletion and an early algal bloom which was terminated by an increase in grazers (mainly Daphnia) were consistently observed in the control microcosm. In comparison with controls, the copper-treated microcosms were associated with reductions in Daphnia and in sensitive algal populations. In all toxicant treatments, copper eliminated the Daphnia and inhibited primary production; the duration of inhibition was prolonged at the higher copper concentrations. At the lowest concentration, recovery was characterized by an algal bloom of copper-resistant green algae, which was followed by a Daphnia bloom. Recovery occurred in most of the 1000-ppb copper-treated microcosms but was usually absent at the 2000-ppb concentration until late in the experiment.All experiments exhibited the same sequence of events, but the timing of these events varied among experiments. Experiments provided similar statistical differences between control and treatment microcosms within the same experiment and gave the same rank order of the day-weighted-by-variable” (DWV) statistic, denned in the text. Comparison of the variable means on a day-by-day analysis of variance did show the experiments to be statistically different because of differences in the timing of events.
An Approach for Development of Structure-Biodegradation Relationships of Organic Chemicals
Authors: Niemi GJ , Veith GD 
Published: February 2009

Success in the development of predictive methods for relating biodegradation rates in water to chemical structure has been elusive. We present a strategy for evaluation of biodegradability of chemicals that involves a combination of structure-biodegradation relationships (SBR) and laboratory testing arranged in a four-tier heirarchy. The first tier involves a search of a data base on biodegradation information. Each subsequent tier consists of a query of potential SBR for the chemical or an experimental laboratory test of the chemical using a tier-specific procedure. The tiered hierarchy proceeds from a data base search, the simplest and cheapest level, to a river die-away test, the most complex and expensive level.
The main purpose of the first three tiers in this strategy is to discriminate readily biodegradable from persistent chemicals. The fourth tier involves the measurement of a biodegradation rate constant under experimental conditions. If a chemical is determined to be degradable, then metabolites of the chemical are also evaluated to identify possible recalcitrant by-products. The approach (a) satisfies the critical need to develop a systematic reference data base on biodegradation endpoints for existing and new chemicals, (b) incorporates the metabolites of biodegradation into the process, and (c) provides an economical means to evaluate chemical biodegradation.