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Sample records for 96-h lc50 values

  1. 96 h LC50, behavioural alterations and histopathological effects due to wastewater toxicity in a freshwater fish Channa punctatus.

    PubMed

    Kaur, Rajbir; Dua, Anish

    2015-04-01

    The aim of the study was to evaluate the toxic impact of wastewater from sites 1 and 2 of Tung Dhab drain in the state of Punjab, India, on fish behaviour, morphology and gill histopathological biomarkers in comparison to control group. Static non-renewal tests were conducted for 96 h to determine LC50 of the wastewater for both sites using five concentrations (6.25-100%). Fish were regularly noticed for any deviation in behaviour and external morphology. Physico-chemical analysis of wastewater was done using standard methods recommended by APHA/AWWA/WEF (2005). Chronic toxicity tests were conducted for 15 and 30 days with sublethal concentrations of wastewater (50-90% of LC50) and gill histopathology was assessed. Wastewater near a paper mill was more toxic as observed from LC50 values of 72.45%. There was evident deterioration of water quality as the recorded values of some parameters were higher than the standard discharge limits. The test fish exhibited increased air gulping and surfacing, erratic movements initially and decreased opercular movements as the exposure period increased. Morphological observations include increased body colouration, mucus secretion, scale loss and haemorrhages on the skin and lower lip. Alterations in the gill histology such as complete lamellar fusion, epithelial lifting and intraepithelial oedema, haemorrhages, lamellar necrosis and aneurysm were noted in the test fish. Results demonstrate that the fish exposed to wastewater from both sites showed significantly greater change in gill organ index (IG) as compared to control fish for 15 and 30 days.

  2. Prediction of the acute toxicity (96-h LC50) of organic compounds to the fathead minnow (Pimephales promelas) using a group contribution method.

    PubMed

    Martin, T M; Young, D M

    2001-10-01

    A group contribution method has been developed to correlate the acute toxicity (96-h LC50) to the fathead minnow (Pimephales promelas) for 397 organic chemicals. Multilinear regression and computational neural networks (CNNs) were used for model building. The models were able to achieve a fairly good correlation of the data (r2 > 0.9). The linear model, which included four specific interaction terms, provided a rapid means of predicting the toxicity of a compound. The CNN model was able to yield virtually the same predictions with or without the four interaction terms that were included in the multilinear model.

  3. Assessment of diclofenac LC50 reference values in juvenile and embryonic stages of the zebrafish (Danio rerio).

    PubMed

    Praskova, E; Voslarova, E; Siroka, Z; Plhalova, L; Macova, S; Marsalek, P; Pistekova, V; Svobodova, Z

    2011-01-01

    The aim of the study was to compare the acute toxicity of diclofenac to juvenile and embryonic stages of the zebrafish (Danio rerio). Acute toxicity tests were performed on the aquarium fish Danio rerio, which is one of the model organisms most commonly used in toxicity testing. The tests were performed using a semi-static method according to OECD guideline No. 203 (Fish, acute toxicity test). Embryo toxicity tests were performed in zebrafish embryos (Danio rerio) in compliance with OECD No. 212 methodology (Fish, short-term toxicity test on embryo and sac-fry stages). The results were subjected to a probit analysis using the EKO-TOX 5.2 programme to determine 96hLC50 and 144hLC50 (median lethal concentration, 50% mortality after a 96 h or 144 h interval, respectively) values of diclofenac. The statistical significance of the difference between LC50 values in juvenile and embryonic stages of Danio rerio was tested using the Mann-Whitney non-parametric test implemented in the Unistat 5.1 programme. The LC50 mean value of diclofenac was 166.6 +/- 9.8 mg/L in juvenile Danio rerio, and 6.11 +/- 2.48 mg/L in embryonic stages of Danio rerio. The study demonstrated a statistically higher sensitivity to diclofenac (P < 0.05) in embryonic stages compared to the juvenile fish.

  4. Genotoxic effects and LC50 value of NaOCl on Orthrias angorae (Steindachner 1897).

    PubMed

    Gül, Süleyman; Ozkan, Oktay; Nur, Gökhan; Aksu, Pinar

    2008-06-01

    Studies show that different organisms used as bio-indicators have indicated several genotoxic and mutagenic effects of disinfected waters. In this study, the 96 h LC(50 )mean value of NaOCl for Orthrias angorae was calculated to be 0.5509 mg/L. The results showed that NaOCl is highly toxic to O. angorae specimens. Statistical analysis demonstrated a significant increase in micronuclei after the induction of 0.5 mg/L NaOCl concentration after 36 h. The same increase has been reported for 0.37 and 0.5 mg/L NaOCl concentrations after 72 h. Even though the MN frequency of 0.37 mg/L was similar after 36 and 72 h, only 72 h micronuclei frequency was statistically significant. The 72 h MN frequency of the negative control group was smaller than 36 h MN frequency of the negative control group. This discrepancy has led to 72 h MN frequency being statistically significant. MN frequency of 0.25 mg/L NaOCl concentration was insignificant when compared to negative test groups. The benzene treatment also caused a significant increase (p < 0.01) in the frequency of micronucleated erythrocytes.

  5. Determination of LC50 and LC95 values of fipronil against Haemaphysalis bispinosa based on adult immersion test.

    PubMed

    Ravindran, Reghu; Amithamol, Krishnan Kavalimakkil; Sunil, Athalathil Ramankutty; Soorya, Valliparambil Chandran; Nair, Suresh Narayanan; Juliet, Sanis; Arunkumar, Nagarajan Selvam; Ajith Kumar, Karapparambu Gopalan; Ghosh, Srikanta

    2014-03-01

    The pattern of mortality of Haemaphysalis bispinosa ticks against fipronil was studied based on adult immersion test. Mortality occurred during 10-19 days post-treatment. The LC50 and LC95 values were calculated as 0.53 and 7.045 ppm, respectively.

  6. Introduction of moribund category to OECD fish acute test and its effect on suffering and LC50 values.

    PubMed

    Rufli, Hans

    2012-05-01

    It has become common practice in many laboratories in Europe to introduce the criterion "moribund" to reduce the suffering in fish acute lethality tests. Fish with severe sublethal symptoms might be declared moribund and are removed from the test as soon as this occurs (premature discontinuation of experiment). Moribund fish affect main study outcomes as the median lethal concentration (LC50) derived on fish declared as moribund may be lower than the conventional LC50. This was evaluated by a retrospective analysis of 328 fish acute toxicity tests of an industry laboratory based on five different definitions of moribund, and of 111 tests from 10 other laboratories from Europe and the United States. Using the criterion of moribund 10 to 23% of the fish were being declared as moribund in 49 to 79% of the studies. In 36 to 52% of the studies, the LC50(moribund) was lower than the conventional LC50 depending on the definitions of moribund. An inclusion of the moribund criterion in an updated Organisation for Economic Cooperation and Development guideline for the acute fish toxicity test would reduce the period of suffering by up to 92 h, lowering the value of the main toxicity endpoint by a factor of approximately 2, and maximal by a factor of approximately 16.

  7. LC50 values for rats acutely exposed to vapors of acrylic and methacrylic acid esters

    SciTech Connect

    Oberly, R.; Tansy, M.F.

    1985-01-01

    Acute exposure studies were conducted using adult male Sprague-Dawley rats to obtain LC50/24 concentrations for the common esters of acrylic and methacrylic acids. The order of acute toxicity was determined to be methyl acrylate > ethyl acrylate > butyl acrylate > butyl methacrylate > methyl methacrylate > ethyl methacrylate. Four-hour daily exposures (excluding weekends) of young adult male rats to 110 ppm methyl acrylate in air over a period of 32 d failed to produce significant differences in body or tissue weights, blood chemistries, gross metabolic performance, and spontaneous small-intestinal motor activities when compared with a sham-exposed group.

  8. Toxicity of an anionic detergent, dodecylbenzene sodium sulfonate, to a freshwater fish, Rita rita: determination of LC50 values by different methods.

    PubMed

    Roy, D

    1988-04-01

    LC50 values and their 95% confidence limits for various intervals of exposure to an anionic detergent, dodecylbenzene sodium sulfonate, have been determined using recommended methods. The advantages and disadvantages of these methods are discussed in light of the variations in the values. Different visible behaviors of the fish under the influence of the detergent have also been explained.

  9. Estimation of human blood LC50 values for use in modeling of in vitro-in vivo data of the ACuteTox project.

    PubMed

    Sjöström, Michael; Kolman, Ada; Clemedson, Cecilia; Clothier, Richard

    2008-08-01

    The main aim of the ACuteTox project, under EU 6th Framework programme, is to investigate whether animal toxicity tests for acute systemic toxicity could be replaced by a combination of alternative assays. Data for 97 reference chemicals was collected in the ACuteTox database (Acutoxbase), designed to handle invitro and invivo (human and animal) lodged data. The principal basis for demonstration of the applicability of invitro tests is the invitro-invivo modeling, by using statistical correlation between invitro IC50 molar values (the 50% inhibitory concentration for the endpoints measured) and human blood molar concentrations LC50 (50% lethal concentrations). The LC50 values were calculated from time-related sub-lethal and lethal blood concentrations determined from human acute poisoning cases. The 3T3 standard NRU assay (3T3 NRU) was chosen, among the various basal cytotoxicity assays, applied in the ACuteTox project, to demonstrate the applicability of the IC50/LC50 values for invitro-invivo modeling. Linear regression analysis between IC50 (x) and LC50 (y) gave an explained variance R2=0.56 for the 67 reference chemicals, for which both sets of data were available. The results demonstrated usefulness of human LC50 values for invitro-invivo evaluation of the predictability of basal cytotoxicity assays for human acute systemic toxicity. The R2 value of 0.56 shows, as in the MEIC study, that additional organ-specific and biokinetic tests are needed in order to improve the predictability.

  10. Using Microtox to predict LC50`s

    SciTech Connect

    Loose, C.M.; Evans, K.A.; Lyons, L.A.

    1994-12-31

    The ability of Microtox to predict Daphnia magna, fathead minnow, and rainbow trout LC50`s has been evaluated with a variety of industrial process chemicals biocides, polymers, amines, dispersants, corrosion and scale inhibitors. The LC50`s of these materials range from less than 1.0 mg/L to greater than 5,000 mg/L. A correlation between Microtox EC50`s and acute LC50`s indicate that Microtox can be used as an effective tool for estimating LC50 values. However, correlations are limited for certain kinds of chemical formulations, such as oil-based materials, surfactant-based materials and some amines.

  11. European Chemicals Agency dossier submissions as an experimental data source: refinement of a fish toxicity model for predicting acute LC50 values.

    PubMed

    Austin, Thomas; Denoyelle, Marieva; Chaudry, Amjad; Stradling, Sam; Eadsforth, Charles

    2015-02-01

    As a result of the stringent data requirements of the Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) regulation, a vast amount of ecotoxicological data has become available through the dissemination portal of the European Chemicals Agency (ECHA). As of April 2014, the database contained 12,439 unique substances from 47,909 dossiers. This vast database could be used to refine existing, or to create new, non-testing methods, such as quantitative structure-activity relationships (QSARs). Acute fish toxicity data were mined from the ECHA database using the eChemPortal; after filtering for single organic substances, 1159 experimental data points remained, representing 564 compounds. To evaluate the quality and accessibility of this data, the authors used the data to refine and improve an existing QSAR. The reliability of the data submitted to the ECHA database, as well as the effectiveness of the Klimisch scoring system, were assessed by comparing the refined QSAR with established QSAR benchmarks. The model developed meets all Organisation for Economic Co-operation and Development principles, has strong internal (leave-one-out internally cross-validated correlation coefficient [Q(2)(LOO)] = 0.91) and external (external coefficient of determination (predicted vs experimental [test set])) validation statistics, and can provide reliable fish median lethal concentration (LC50) predictions for non-polar narcotics. Although some issues with dossier misinformation were discovered, it was found that the ECHA dissemination portal is a valuable and reliable data source. When queried using the eChemPortal, chemical dossiers containing reliable data could be found quickly. The ECHA dissemination portal holds great potential for future QSAR development and improvement, such as updating QSARs within the Ecological Structure-Activity Relationships (ECOSAR) program.

  12. [Estimation of LC50 of chemicals to rainbow trout by fragment constant method].

    PubMed

    Xi, X; Xu, F; Cao, J; Tao, S

    2001-07-01

    A fragment constant model for prediction of 96 h LC50 of chemicals to rainbow trout was developed based on measured experimental data of 258 chemicals collected from the literature. The accuracy and the robustness of the model were discussed. The coefficient of determination of the model is 0.9495 and the mean residual is 0.42 log-unit. The model is robust for both individual chemical or chemical class.

  13. Chlorosilane acute inhalation toxicity and development of an LC50 prediction model.

    PubMed

    Jean, Paul A; Gallavan, Robert H; Kolesar, Gary B; Siddiqui, Waheed H; Oxley, Jon A; Meeks, Robert G

    2006-07-01

    The acute inhalation toxicity of 10 chlorosilanes was investigated in Fischer 344 rats using a 1-h whole-body vapor inhalation exposure and a 14-day recovery period. The median lethal concentration (LC50(1)) for each material was calculated from the nominal exposure concentrations and mortality. Experimentally derived LC50(1) values for monochlorosilanes (4257-4478 ppm) were greater than those for dichlorosilanes (1785-2092 ppm), which were greater than those for trichlorosilanes (1257-1611 ppm). Apparent was a strong structure-activity relationship (r2 = .97) between chlorine content and LC50(1) value. Estimated LC50(1) values for mono-, di-, and trichlorosilanes were determined to be 3262, 1639, and 1066 ppm, respectively, utilizing this relationship and the lower limit of the 95% prediction interval. The LC50(1) values determined in this series of studies were greater than that reported for hydrogen chloride (3124 ppm), when expressed on a chlorine equivalence basis (3570-5248 ppm), demonstrating that the acute toxicity of these chlorosilanes is similar to or less than that for hydrogen chloride. The good correlation between chlorine content and LC50(1) provides a sound basis for estimation of LC50(1) for chlorosilanes not already evaluated. The use of structure-activity relationships is consistent with the chemical industry and federal agency initiatives to reduce, refine, and/or replace the use of animals in testing without compromising the quality of health and safety assessments.

  14. A QSAR model for predicting toxicity (LC50) to rainbow trout.

    PubMed

    Tao, S; Xi, Xiaohuan; Xu, Fuliu; Dawson, Richard

    2002-06-01

    A fragment constant method for prediction of toxicity (LC50) to rainbow trout was developed based on the experimental LC50 values of 258 chemicals obtained from the literature. The dataset was randomly divided into a training set and a validation set for purposes of model development and validation. The final model was established using all of the experimental LC50 values by pooling the two sets together. The coefficient of the determination for the final model was 0.9495 with a mean residual of 0.42 log-units. The model's robustness was tested using jackknife tests.

  15. Probabilistic neural networks modeling of the 48-h LC50 acute toxicity endpoint to Daphnia magna.

    PubMed

    Niculescu, S P; Lewis, M A; Tigner, J

    2008-01-01

    Two modeling experiments based on the maximum likelihood estimation paradigm and targeting prediction of the Daphnia magna 48-h LC50 acute toxicity endpoint for both organic and inorganic compounds are reported. The resulting models computational algorithms are implemented as basic probabilistic neural networks with Gaussian kernel (statistical corrections included). The first experiment uses strictly D. magna information for 971 structures as training/learning data and the resulting model targets practical applications. The second experiment uses the same training/learning information plus additional data on another 29 compounds whose endpoint information is originating from D. pulex and Ceriodaphnia dubia. It only targets investigation of the effect of mixing strictly D. magna 48-h LC50 modeling information with small amounts of similar information estimated from related species, and this is done as part of the validation process. A complementary 81 compounds dataset (involving only strictly D. magna information) is used to perform external testing. On this external test set, the Gaussian character of the distribution of the residuals is confirmed for both models. This allows the use of traditional statistical methodology to implement computation of confidence intervals for the unknown measured values based on the models predictions. Examples are provided for the model targeting practical applications. For the same model, a comparison with other existing models targeting the same endpoint is performed.

  16. Determination of wastewater LC50 of the different process stages of the textile industry.

    PubMed

    Villegas-Navarro, A; Ramírez-M, Y; Salvador-S, M S; Gallardo, J M

    2001-01-01

    Textile plants are very important sources of toxic discharges. The purpose of the research described in this paper was to use bioassays with daphnids to determine the LC50 values of textile wastewater samples taken from different stages of the finishing textile industry. Toxicity due to dyeing, chlorination, and the absence of adequate physicochemical conditions for daphnid survival were considered. Wastewater samples corresponding to each process stage were collected at five finishing textile industries and assayed according to previously published procedures. The sensitivity of daphnids to chemicals was assayed using sodium dodecyl sulfate and was similar to other reports (14.6+/-6.8 vs 14.5+/-2.3 mg/L). All effluents from the five company samples were toxic in terms of LC50 and exhibited very high toxicity with acute toxicity unit (ATU) levels between 2.2 and 960, indicating that the five textile industries produced toxic water. The sensory characteristics indicated that the dyes contributed to overall sample toxicity at all process stages. The most toxic contaminant seemed to be ClO- at levels between 0.2 and 6.8 mg/L, suggesting that further research is needed on the economic costs of stage-by-stage and total effluent treatments.

  17. Incorporating variability in point estimates in risk assessment: Bridging the gap between LC50 and population endpoints.

    PubMed

    Stark, John D; Vargas, Roger I; Banks, John E

    2015-07-01

    Historically, point estimates such as the median lethal concentration (LC50) have been instrumental in assessing risks associated with toxicants to rare or economically important species. In recent years, growing awareness of the shortcomings of this approach has led to an increased focus on analyses using population endpoints. However, risk assessment of pesticides still relies heavily on large amounts of LC50 data amassed over decades in the laboratory. Despite the fact that these data are generally well replicated, little or no attention has been given to the sometime high levels of variability associated with the generation of point estimates. This is especially important in agroecosystems where arthropod predator-prey interactions are often disrupted by the use of pesticides. Using laboratory derived data of 4 economically important species (2 fruit fly pest species and 2 braconid parasitoid species) and matrix based population models, the authors demonstrate in the present study a method for bridging traditional point estimate risk assessments with population outcomes. The results illustrate that even closely related species can show strikingly divergent responses to the same exposures to pesticides. Furthermore, the authors show that using different values within the 95% confidence intervals of LC50 values can result in very different population outcomes, ranging from quick recovery to extinction for both pest and parasitoid species. The authors discuss the implications of these results and emphasize the need to incorporate variability and uncertainty in point estimates for use in risk assessment.

  18. LC50 Determination of tert-Butyl Acetate using a Nose Only Inhalation Exposure in Rats.

    PubMed

    Yang, Young-Su; Lee, Jinsoo; Kwon, Soonjin; Seo, Heung-Sik; Choi, Seong-Jin; Yu, Hee-Jin; Song, Jeong-Ah; Lee, Kyuhong; Lee, Byoung-Seok; Heo, Jeong-Doo; Cho, Kyu-Hyuk; Song, Chang-Woo

    2010-12-01

    tert-Butyl acetate (TBAc) is an organic solvent, which is commonly used in architectural coatings and industrial solvents. It has recently been exempted from the definition of a volatile organic compound (VOC) by the Air Resources Board (ARB) . Since the use of TBAc as a substitute for other VOCs has increased, thus its potential risk in humans has also increased. However, its inhalation toxicity data in the literature are very limited. Hence, inhalation exposure to TBAc was carried out to investigate its toxic effects in this study. Adult male rats were exposed to TBAc for 4 h for 1 day by using a nose-only inhalation exposure chamber (low dose, 2370 mg/m(3) (500 ppm) ; high dose, 9482 mg/m(3) (2000 ppm) ) . Shamtreated control rats were exposed to clean air in the inhalation chamber for the same period. The animals were killed at 2, 7, and 15 days after exposure. At each time point, body weight measurement, bronchoalveolar lavage fluid (BALF) analysis, histopathological examination, and biochemical assay were performed. No treatment-related abnormal effects were observed in any group according to time course. Based on those findings, the median lethal concentration (LC50) of TBAc was over 9482 mg/m(3) in this study. According to the MSDS, the 4 h LC50 for TBAc for rats is over 2230 mg/m(3). We suggested that this value is changed and these findings may be applied in the risk assessment of TBAc which could be beneficial in a sub-acute study.

  19. The relationship of total copper 48-h LC50s to Daphnia magna dry weight

    SciTech Connect

    Lazorchak, J.M. ); Waller, W.T. )

    1993-05-01

    A study was conducted with Daphnia magna to determine the effect of neonate weight loss or lack of weight gain on experimentally derived copper 48-h LC50s. Standard unfed tests as well as algal-fed (Selenastrum capricornutum) tests were used to look at weight loss and gain. No significant relationship was found between amount of weight loss and copper LC50s. However, dry weight of unfed and algal-fed control organisms could be used to predict total copper LC50s.

  20. Comparison of the Microtox test with the 96-hr LC50 test for the harpacticoid Nitocra spinipes

    SciTech Connect

    Tarkpea, M.; Hansson, M.; Samuelsson, B.

    1986-04-01

    A comparison between the static 96-hr LC50 test with the brackish water harpacticoid Nitocra spinipes and the Microtox (Beckman Instruments, Inc.) screening method has been done. The relationship between the two bioassays were evaluated for 16 pure and technical chemicals and 11 complex effluents from different types of industries. The correlation between the 96-hr LC50 values for Nitocra and the 5-, 15-, and 30-min effective concentration (EC50) for pure and technical chemicals had R2 values ranging between 0.751 and 0.796. A somewhat better correlation was shown between the two test methods for the complex effluents with R2 values ranging from 0.903 to 0.927. The sensitivity of the two tests for the actual types of samples were found to be in the same order of magnitude. Investigations concerning pretreatments of three chemicals (dibutyl phthalate, 1-octanol, and pentachlorophenol) fairly insoluble in water (less than 1000 mg/liter) have been done. Three solvents, acetone, dimethyl sulfoxide (DMSO), and propylene glycol, were studied with the Microtox system in a low concentration (500 mg/liter). Acetone exerted a slightly stimulatory effect and propylene glycol a slight reduction effect on bacterial luminescence.

  1. Use of life tables and LC50 tests to evaluate chronic and acute toxicity effects of copper on the marine copepod Tisbe furcata (Baird)

    SciTech Connect

    Bechmann, R.K. . Dept. of Marine Zoology and Marine Chemistry)

    1994-09-01

    Cohorts of the epiphytic marine copepod Tisbe furcata were chronically exposed to copper in life-table experiments to test whether ecologically relevant impacts can occur at sublethal concentrations. Data on fecundity, longevity, and rate of development were used to calculate r[sub m]--the intrinsic rate of natural increase. Acute toxicity tests were done to compare the concentrations of copper affecting individual lethality and population biology. The LC50 value for Tisbe furcata nauplii was 2.8 [mu]M copper. The results from the life-table experiments show that 0.9 [mu]M copper can cause significant negative effects on demographic parameters (total production of nauplii, life span, and reproductive period for fertile females) and reduce the percentage of fertile females leading to a 61% reduction of r[sub m]. However, r[sub m] was still positive at 0.9 [mu]M copper, and the net reproductive rate (R[sub 0]) indicated a fivefold increase in population size from one generation to the next. Although there were no significant effects of copper at 0.5 [mu]M, there was a negative trend in almost all the demographic parameters, indicating that the observed 10% reduction of r[sub m] at this concentration was an effect of copper. For the substances tested so far with both acute LC50 tests and life-table experiments, r[sub m] was not reduced at concentrations below LC50/10. When life-table experiments are used as part of environmental hazard assessments, concentrations below LC50/10 should be tested to detect substances that are potentially harmful to the environment at sublethal concentrations, rather than testing concentrations close to LC50.

  2. Alternative acute inhalation toxicity testing by determination of the concentration-time-mortality relationship: experimental comparison with standard LC50 testing

    SciTech Connect

    Zwart, A.; Arts, J.H.; Ten Berge, W.F.; Appelman, L.M. )

    1992-06-01

    A new design for acute inhalation toxicity testing was evaluated and compared with results obtained according to OECD guideline 403. The new design consists of a range-finding test, which is compatible with a conventional limit test, and can be followed by determination of a concentration-time-mortality relationship, enabling calculation of LC50 (50% mortality exposure concentration) values. By exposing pairs of rats for different periods of time to about four different test concentrations in a nose-only exposure unit, LT50 (50% mortality exposure time) values were obtained for five pairs of animals per concentration. The mortality data of the approximate 20 time-concentration combinations were used to calculate the probit relationship. Estimated mortality responses from these probit relations were compared with mortality figures obtained by exposing groups of five male rats and five female rats whole-body according to conventional toxicity testing. In general, there was good correspondence between the estimated and the observed mortality response. In this study, the determination of the concentration-time-mortality relationship takes about the same number of animals (40-50) as the conventional LC50 procedure according to the OECD guideline 403. However, the new method has several additional advantages such as: (A) LC50 values are obtained over a 10-fold range in time, with the potential of decreasing the number of animals used when regulations require acute toxicity data for different periods of exposure. (B) The obtained relationship contains considerably more valuable information for risk assessment than the LC50 value.

  3. A review of available LC/50/ data. [on toxic gases encountered in fires

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Cumming, H. J.

    1977-01-01

    Several gaseous products of pyrolysis and combustion have been evaluated for LC/50/, defined as the concentration of toxic gas in the atmosphere being inhaled by test animals that will produce death in 50% of the animals within a given time period. The products tested included CO, HCl, HF, HCN, NO2, and SO2. It was found that HCN and NO2 were consistently the most toxic of the gases reviewed, and that mice were more susceptible than rats to HCl and HF, although less susceptible than rats to NO2. Extrapolation of LC/50/ data to humans indicates that metabolic rate may be a valid basis for extrapolation when the toxicity mechanism is interference with oxygen transport and utilization, or pulmonary edema, but not when it is irritation and damage to the upper respiratory tract.

  4. Sensitivity of species to chemicals: dose-response characteristics for various test types (LC(50), LR(50) and LD(50)) and modes of action.

    PubMed

    Hendriks, A Jan; Awkerman, Jill A; de Zwart, Dick; Huijbregts, Mark A J

    2013-11-01

    While variable sensitivity of model species to common toxicants has been addressed in previous studies, a systematic analysis of inter-species variability for different test types, modes of action and species is as of yet lacking. Hence, the aim of the present study was to identify similarities and differences in contaminant levels affecting cold-blooded and warm-blooded species administered via different routes. To that end, data on lethal water concentrations LC50, tissue residues LR50 and oral doses LD50 were collected from databases, each representing the largest of its kind. LC50 data were multiplied by a bioconcentration factor (BCF) to convert them to internal concentrations that allow for comparison among species. For each endpoint data set, we calculated the mean and standard deviation of species' lethal level per compound. Next, the means and standard deviations were averaged by mode of action. Both the means and standard deviations calculated depended on the number of species tested, which is at odds with quality standard setting procedures. Means calculated from (BCF) LC50, LR50 and LD50 were largely similar, suggesting that different administration routes roughly yield similar internal levels. Levels for compounds interfering biochemically with elementary life processes were about one order of magnitude below that of narcotics disturbing membranes, and neurotoxic pesticides and dioxins induced death in even lower amounts. Standard deviations for LD50 data were similar across modes of action, while variability of LC50 values was lower for narcotics than for substances with a specific mode of action. The study indicates several directions to go for efficient use of available data in risk assessment and reduction of species testing.

  5. Sensitivity of species to chemicals: dose-response characteristics for various test types (LC(50), LR(50) and LD(50)) and modes of action.

    PubMed

    Hendriks, A Jan; Awkerman, Jill A; de Zwart, Dick; Huijbregts, Mark A J

    2013-11-01

    While variable sensitivity of model species to common toxicants has been addressed in previous studies, a systematic analysis of inter-species variability for different test types, modes of action and species is as of yet lacking. Hence, the aim of the present study was to identify similarities and differences in contaminant levels affecting cold-blooded and warm-blooded species administered via different routes. To that end, data on lethal water concentrations LC50, tissue residues LR50 and oral doses LD50 were collected from databases, each representing the largest of its kind. LC50 data were multiplied by a bioconcentration factor (BCF) to convert them to internal concentrations that allow for comparison among species. For each endpoint data set, we calculated the mean and standard deviation of species' lethal level per compound. Next, the means and standard deviations were averaged by mode of action. Both the means and standard deviations calculated depended on the number of species tested, which is at odds with quality standard setting procedures. Means calculated from (BCF) LC50, LR50 and LD50 were largely similar, suggesting that different administration routes roughly yield similar internal levels. Levels for compounds interfering biochemically with elementary life processes were about one order of magnitude below that of narcotics disturbing membranes, and neurotoxic pesticides and dioxins induced death in even lower amounts. Standard deviations for LD50 data were similar across modes of action, while variability of LC50 values was lower for narcotics than for substances with a specific mode of action. The study indicates several directions to go for efficient use of available data in risk assessment and reduction of species testing. PMID:23932508

  6. Determination of LC50 and sub-chronic neurotoxicity of diesel exhaust nanoparticles.

    PubMed

    Durga, M; Devasena, T; Rajasekar, A

    2015-09-01

    Air pollution is a major problem faced globally and is seen associated with central nervous system (CNS) disorders like neuropathology and neuro-inflammation. Here, we investigated the CNS disorders as a result of sub-chronic exposure (90 days) to diesel exhaust nanoparticles (DENPs) and explored the minimal levels of DENPs needed to exhibit the early mediators of neuro-inflammation and neuropathology. Male and female wistar rats (6 rats per group) were exposed to DENPs (1/5th, 1/10th and 1/15th LC50) by inhalation for 4h per day, 5 days per week over 90 days and neurotoxicity end-points were analyzed. DENP exposure caused elevation in levels of pro-inflammatory cytokines, amyloid beta 42 (Aβ 42), reactive oxygen species (ROS), hydrogen peroxide (H2O2), nitrate (NO3(-)), nitrite (NO2(-)) and apurinic/apyrimidinic sites (AP) at varying degrees at different sections of rat brain. Hence, exposure to DENPs resulted in dose-dependent toxicity and was closely correlated to increased inflammation, DNA damage and oxidative stress.

  7. Compliance of LC50 and NOEC data with Benford's Law: an indication of reliability?

    PubMed

    de Vries, Pepijn; Murk, Albertinka J

    2013-12-01

    Reliability of research data is essential, especially when potentially far-reaching conclusions will be based on them. This is also, amongst others, the case for ecotoxicological data used in risk assessment. Currently, several approaches are available to classify the reliability of ecotoxicological data. The process of classification, such as using the Klimisch score, is time-consuming and focuses on the application of standardised protocols and the documentation of the study. The presence of irregularities and the integrity of the performed work, however, are not addressed. The present study shows that Benford's Law, based on the occurrence of first digits following a logarithmic scale, can be applied to ecotoxicity test data for identifying irregularities. This approach is already successfully applied in accounting. Benford's Law can be used as reliability indicator, in addition to existing reliability classifications. The law can be used to efficiently trace irregularities in large data sets of interpolated (no) effect concentrations such as LC50s (possibly the result of data manipulation), without having to evaluate the source of each individual record. Application of the law to systems in which large amounts of toxicity data are registered (e.g., European Commission Regulation concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals) can therefore be valuable.

  8. Hormonal and electrolyte responses of conscious sheep to 96 h of hypoxia.

    PubMed

    Curran-Everett, D C; Claybaugh, J R; Miki, K; Hong, S K; Krasney, J A

    1988-08-01

    Hypoxia alters the relationship of aldosterone secretion to plasma renin activity. The potential role plasma electrolytes play in this modification is not clear. This study analyzed the interrelationships among renin, aldosterone, vasopressin (ADH), and plasma electrolytes during 96 h of normobaric hypoxia. Eight ewes were exposed, in discrete experiments, to hypocapnic hypoxia [arterial O2 tension (PaO2) 37-42 mmHg, arterial CO2 tension (PaCO2) 26-28 mmHg] and eucapnic hypoxia (PaO2 40-43 mmHg, PaCO2 28-31 mmHg) by N2 dilution in an environmental chamber. Urine output (24 h) was measured, and arterial plasma samples were collected during the normoxic control period and at 24-h intervals of hypoxia. Plasma Na+, K+, renin, and ADH levels did not change from the normoxic values during either hypocapnic or eucapnic hypoxia. However, urinary aldosterone excretion [critical significance (alpha) less than 0.046] and K+ excretion (alpha less than 0.046) decreased markedly during each type of hypoxia. All sheep developed a pronounced negative K+ balance by 96 h of hypoxia. These data suggest that plasma K+ concentration is preserved by movement of K+ out of the intracellular compartment; this change in K+ distribution may inhibit aldosterone secretion during hypoxia.

  9. A mechanistic explanation for the In(LC50) vs In(hardness) adjustment equation for metals

    SciTech Connect

    Meyer, J.S.

    1999-03-15

    The author demonstrates that a combination of (a) competitive binding of transition-metal cations, hardness cations, and protons to transition-metal-binding sites on fish gills and (b) aqueous complexation of transition-metal cations by HCO{sub 3}{sup {minus}} and CO{sub 3}{sup 2{minus}} explains why the regression slopes of In(LC50) vs In(hardness) for five divalent transition metals (Cd, Cu, Ni, Pb, and Zn) are {approximately}1, where LC50 is the median lethal concentration. For these calculations, the author assumed the amount of the transition metal bound to the fish gill at 50% mortality is constant (i.e., independent of water quality). Although the slopes theoretically should vary between 0 and 2, a slope of {approximately}1 is expected at midrange hardness if alkalinity covaries with hardness--a common condition in most laboratory toxicity tests. But if alkalinity is held constant while hardness is varied, a slope of {approximately}0.5 is expected at midrange hardness. Although predictions of LC50s using regressions of In(LC50) vs In(hardness) might be acceptable for regulating discharges of transition metals to waters in the midrange of hardness, extrapolations beyond this range might drastically overpredict metal toxicity.

  10. Incorporating variability in point estimates in risk assessment: bridging the gap between LC50 and population endpoints

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Historically, the use of point estimates such as the LC50 has been instrumental in assessing the risk associated with toxicants to rare or economically important species. In recent years, growing awareness of the shortcomings of this approach has led to an increased focus on analyses using populatio...

  11. Per- and polyfluoro toxicity (LC(50) inhalation) study in rat and mouse using QSAR modeling.

    PubMed

    Bhhatarai, Barun; Gramatica, Paola

    2010-03-15

    Fully or partially fluorinated compounds, known as per- and polyfluorinated chemicals are widely distributed in the environment and released because of their use in different household and industrial products. Few of these long chain per- and polyfluorinated chemicals are classified as emerging pollutants, and their environmental and toxicological effects are unveiled in the literature. This has diverted the production of long chain compounds, considered as more toxic, to short chains, but concerns regarding the toxicity of both types of per- and polyfluorinated chemicals are alarming. There are few experimental data available on the environmental behavior and toxicity of these compounds, and moreover, toxicity profiles are found to be different for the types of animals and species used. Quantitative structure-activity relationship (QSAR) is applied to a combination of short and long chain per- and polyfluorinated chemicals, for the first time, to model and predict the toxicity on two species of rodents, rat (Rattus) and mouse (Mus), by modeling inhalation (LC(50)) data. Multiple linear regression (MLR) models using the ordinary-least-squares (OLS) method, based on theoretical molecular descriptors selected by genetic algorithm (GA), were used for QSAR studies. Training and prediction sets were prepared a priori, and these sets were used to derive statistically robust and predictive (both internally and externally) models. The structural applicability domain (AD) of the model was verified on a larger set of per- and polyfluorinated chemicals retrieved from different databases and journals. The descriptors involved, the similarities, and the differences observed between models pertaining to the toxicity related to the two species are discussed. Chemometric methods such as principal component analysis (PCA) and multidimensional scaling (MDS) were used to select most toxic compounds from those within the AD of both models, which will be subjected to experimental tests

  12. Application of a sigmapolycyclic aromatic hydrocarbon model and a logistic regression model to sediment toxicity data based on a species-specific, water-only LC50 toxic unit for Hyalella azteca.

    PubMed

    Lee, J H; Landrum, P F; Field, L J; Koh, C H

    2001-09-01

    Two models, a sigmapolycyclic aromatic hydrocarbon (PAH) model based on equilibrium partitioning theory and a logistic-regression model, were developed and evaluated to predict sediment-associated PAH toxicity to Hyalella azteca. A sigmaPAH model was applied to freshwater sediments. This study is the first attempt to use a sigmaPAH model based on water-only, median lethal concentration (LC50) toxic unit (TU) values for sediment-associated PAH mixtures and its application to freshwater sediments. To predict the toxicity (i.e., mortality) from contaminated sediments to H. azteca, an interstitial water TU, calculated as the ambient interstitial water concentration divided by the water-only LC50 in which the interstitial water concentrations were predicted by equilibrium partitioning theory, was used. Assuming additive toxicity for PAH, the sum of TUs was calculated to predict the total toxicity of PAH mixtures in sediments. The sigmaPAH model was developed from 10- and 14-d H. azteca water-only LC50 values. To obtain estimates of LC50 values for a wide range of PAHs, a quantitative structure-activity relationship (QSAR) model (log LC50 - log Kow) with a constant slope was derived using the time-variable LC50 values for four PAH congeners. The logistic-regression model was derived to assess the concentration-response relationship for field sediments, which showed that 1.3 (0.6-3.9) TU were required for a 50% probability that a sediment was toxic. The logistic-regression model reflects both the effects of co-occurring contaminants (i.e., nonmeasured PAH and unknown pollutants) and the overestimation of exposure to sediment-associated PAH. An apparent site-specific bioavailability limitation of sediment-associated PAH was found for a site contaminated by creosote. At this site, no toxic samples were less than 3.9 TU. Finally, the predictability of the sigmaPAH model can be affected by species-specific responses (Hyalella vs Rhepoxynius); chemical specific (PAH vs DDT in

  13. Critical body residues linked to octanol-water partitioning, organism composition, and LC50 QSARs: meta-analysis and model.

    PubMed

    Hendriks, A Jan; Traas, Theo P; Huijbregts, Mark A J

    2005-05-01

    To protect thousands of species from thousands of chemicals released in the environment, various risk assessment tools have been developed. Here, we link quantitative structure-activity relationships (QSARs) for response concentrations in water (LC50) to critical concentrations in organisms (C50) by a model for accumulation in lipid or non-lipid phases versus water Kpw. The model indicates that affinity for neutral body components such as storage fat yields steep Kpw-Kow relationships, whereas slopes for accumulation in polar phases such as proteins are gentle. This pattern is confirmed by LC50 QSARs for different modes of action, such as neutral versus polar narcotics and organochlorine versus organophosphor insecticides. LC50 QSARs were all between 0.00002 and 0.2Kow(-1). After calibrating the model with the intercepts and, for the first time also, with the slopes of the LC50 QSARs, critical concentrations in organisms C50 are calculated and compared to an independent validation data set. About 60% of the variability in lethal body burdens C50 is explained by the model. Explanations for differences between estimated and measured levels for 11 modes of action are discussed. In particular, relationships between the critical concentrations in organisms C50 and chemical (Kow) or species (lipid content) characteristics are specified and tested. The analysis combines different models proposed before and provides a substantial extension of the data set in comparison to previous work. Moreover, the concept is applied to species (e.g., plants, lean animals) and substances (e.g., specific modes of action) that were scarcely studied quantitatively so far.

  14. Pathogenicity, Ovicidal Action, and Median Lethal Concentrations (LC50) of Entomopathogenic Fungi against Exotic Spiralling Whitefly, Aleurodicus dispersus Russell

    PubMed Central

    Palaniappan, Karuppuchamy; Manickavasagam Pillai, Kalyanasundaram; Subbarayalu, Mohankumar; Madhaiyan, Ravi

    2013-01-01

    Biological control using entomopathogenic fungi could be a promising alternative to chemical control. Entomopathogenic fungi, Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae (Metschnikoff) Sorokin, Lecanicillium lecanii (Zimmerm.) Zare and Gams, and Paecilomyces fumosoroseus (Wize) Brown and Smith, were tested for their pathogenicity, ovicidal effect, and median lethal concentrations (LC50) against exotic spiralling whitefly, Aleurodicus dispersus Russell. The applications were made at the rate of 2 × 109 conidia mL−1 for evaluating the pathogenicity and ovicidal effect of entomopathogenic fungi against A. dispersus. The results of pathogenicity test showed that P. fumosoroseus (P1 strain) was highly pathogenic to A. dispersus recording 100% mortality at 15 days after treatment (DAT). M. anisopliae (M2 strain) had more ovicidal effect causing 37.3% egg mortality at 8 DAT. However, L. lecanii (L1 strain) caused minimum egg hatchability (23.2%) at 10 DAT as compared to control (92.6%). The lowest LC50 produced by P. fumosoroseus (P1 strain) as 8.189 × 107 conidia mL−1 indicated higher virulence against A. dispersus. Hence, there is potential for use of entomopathogenic fungi in the field conditions as an alternate control method in combating the insect pests and other arthropod pests since they are considered natural mortality agents and are environmentally safe. PMID:24455279

  15. Subacute toxicity testing with young birds: Response in relation to age and intertest variability of LC50 estimates

    USGS Publications Warehouse

    Hill, E.F.; Camardese, M.B.; Lamb, D.W.; Kenaga, E.E.

    1982-01-01

    The variability in toxic response of Japanese quail (Coturnix coturnix japonica) to a standardized 5-day subacute feeding trial was studied while age was increased at weekly intervals from 1 to 21 days and at different times with 14-day-old birds. The objectives were to identify the strengths and limitations of this subacute toxicity protocol and to provide possible explanations for differences in response among the various classes of pesticides. The variables included the median lethal concentration (LC50), the dose-response slope, food consumption, mortality patterns, and procedures of preparing toxic diets. Carbamate, organophosphate, chlorinated hydrocarbon, and organic mercury compounds were represented. A total of 60 subacute tests were involved in this evaluation. The general conclusions of the study are as follows: (1) The basic protocol yields good within-laboratory reproducibility of results. (2) The LC50s increase as birds grow older, and the change was reasonably predictable between 7 and 21 days of age. (3) Monitoring of time-related response patterns, such as food consumption, onset and remission of overt toxicity, and mortality, is critical to the evaluation of potential hazard. (4) Different orders of toxicity may occur at different ages for an array of compounds, but differences do not appear to be large enough to seriously alter the interpretation. (5) For optimal comparisons, all testing should be conducted on birds of a single age.

  16. Aquatic toxicity of acrylates and methacrylates: quantitative structure-activity relationships based on Kow and LC50

    SciTech Connect

    Reinert, K.H.

    1987-12-01

    Recent EPA scrutiny of acrylate and methacrylate monomers has resulted in restrictive consent orders and Significant New Use Rules under the Toxic Substances Control Act, based on structure-activity relationships using mouse skin painting studies. The concern is centered on human health issues regarding worker and consumer exposure. Environmental issues, such as aquatic toxicity, are still of concern. Understanding the relationships and environmental risks to aquatic organisms may improve the understanding of the potential risks to human health. This study evaluates the quantitative structure-activity relationships from measured log Kow's and log LC50's for Pimephales promelas (fathead minnow) and Carassius auratus (goldfish). Scientific support of the current regulations is also addressed. Two monomer classes were designated: acrylates and methacrylates. Spearman rank correlation and linear regression were run. Based on this study, an ecotoxicological difference exists between acrylates and methacrylates. Regulatory activities and scientific study should reflect this difference.

  17. In vitro tests to establish LC50 and discriminating concentrations for fipronil against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) and their standardization.

    PubMed

    Castro-Janer, E; Rifran, L; Piaggio, J; Gil, A; Miller, R J; Schumaker, T T S

    2009-05-26

    Laboratory test was carried out on larvae and adults of the cattle tick, Rhipicephalus (Boophilus) microplus, to determine fipronil toxicity. Adult immersion test (AIT, N=26), larval immersion test (LIT, N=71) and larval packet test (LPT, N=41) were standardized using susceptible strain (Mozo). Dose-response curves were compared with a fipronil resistant strain. Four variables were analyzed from AIT results: mortality, weight of eggs on day 7 and on day 14, index of fertility, and index of fecundity. For larval test, dose mortality curves were analyzed. In spite of the high LC(50) variability, all variables determined for AIT were appropriate to discriminate both strains. AIT and LIT had more sensitivity than LPT, with larger resistance factors. It was used two times LC(99.9) as discriminating doses (DCs) following FAO suggestion. For mortality by AIT, LIT and LPT the DCs were estimated: 4.98ppm, 7.64ppm and 2365.8ppm, respectively, for Mozo strain. DCs mortality values estimated for resistant strain by AIT, LIT and LPT were: 6.96x10(5)ppm, 343.26ppm and 5.7x10(3)ppm, respectively and their respective resistant factors were: 202.4, 5.36 and 1.52. Protocols for AIT, LIT and LPT have been presented in this paper.

  18. Complete Genome Sequence of Enteroinvasive Escherichia coli O96:H19 Associated with a Severe Foodborne Outbreak.

    PubMed

    Pettengill, Emily A; Hoffmann, Maria; Binet, Rachel; Roberts, Richard J; Payne, Justin; Allard, Marc; Michelacci, Valeria; Minelli, Fabio; Morabito, Stefano

    2015-08-06

    We present here the complete genome sequence of a strain of enteroinvasive Escherichia coli O96:H19 from a severe foodborne outbreak in a canteen in Italy in 2014. The complete genome may provide important information about the acquired pathogenicity of this strain and the transition between commensal and pathogenic E. coli.

  19. Utility of Gene Expression and Ex vivo Steroid Production in a 96 h Assay for Predicting Impacts of Endocrine Active Chemicals on Fish Reproduction.

    EPA Science Inventory

    Development of efficient test methods that can generate reliable data to inform risk assessment is an on-going challenge in the field of ecotoxicology. In the present study we evaluated whether a 96 h in vivo assay focused on a small number of quantitative real-time polymerase ch...

  20. Developmental toxicity of p,p'-dichlorodiphenyltrichloroethane, 2,4,6-trinitrotoluene, their metabolites, and benzo[a]pyrene in Xenopus laevis embryos.

    PubMed

    Saka, Masahiro

    2004-04-01

    Since 1995, high incidences of deformed frogs have been documented in Kitakyushu, Japan. In this area, relatively high concentrations of DDT, trinitrotoluene (TNT), their metabolites (p,p'-dichlorodiphenyldichloroethylene [DDE], p,p'-dichlorodiphenyldichloroethane [DDD], 2-amino-4,6-dinitrotoluene [2ADNT], and 4-amino-2,6-dinitrotoluene [4ADNT]), and benzo[a]pyrene [BaP]) have been identified from field samples. I used a standardized assay with Xenopus laevis embryos (frog embryo teratogenesis assay--Xenopus, FETAX) to examine the developmental toxicity of these compounds. Both DDE and BaP were considered nearly nontoxic in embryonic development because they induced low (< 10%) mortality and malformation incidence even at the highest concentrations tested (DDE, 393 microM; BaP, 13.2 microM). The DDD (96-h median lethal concentration [LC50] = 44.1 microM, 96-h median effective concentration [EC50] for malformation = 14.9 microM) was more lethal and teratogenic than its parent compound, DDT (96-h LC50 = 101 microM, 96-h EC50 = 41.5 microM). Predominant symptoms observed were axial malformations (DDT and DDD) and irregular gut coiling (DDT). However, DDT and DDD should not act as major lethal or teratogenic toxicants in the aquatic environment within a short-term exposure via water because their 96-h LC50 and 96-h EC50 values were extremely high, considering their low solubility in water. The TNT (96-h LC50 = 16.7 microM) was more lethal than 2ADNT (96-h LC50 = 166 microM) or 4ADNT (96-h LC50 = 115 microM). Although 4ADNT (96-h EC50 = 85.8 microM) induced various tadpole malformations, it was a weak teratogen compared with TNT (96-h EC50 = 9.78 microM) and 2ADNT (96-h EC50 = 16.9 microM). The most typical malformations observed were axial malformations, eye abnormalities (TNT), edema, and irregular gut coiling (2ADNT and 4ADNT). The 96-h LC50 and 96-h EC50 values of TNT, 2ADNT, and 4ADNT were lower than their saturated concentrations in water. Therefore, these

  1. Histopathological biomarkers in juvenile silver catfish (Rhamdia quelen) exposed to a sublethal lead concentration.

    PubMed

    Muñoz, Lautaro; Weber, Paula; Dressler, Valderi; Baldisserotto, Bernardo; Vigliano, Fabricio Andrés

    2015-03-01

    The aim of this study was to determine the 96-h lethal concentration (96-h LC50) of lead (Pb) in silver catfish, Rhamdia quelen, and to determine histopathological biomarkers in fish exposed for 96-h to a sublethal concentration at 25% of the LC50. The 96-h LC50 was 108 mgl(-1). In gills, the length and thickness of lamella and thickness of the filament epithelium were significantly higher in fish exposed to Pb for 48-h than in control fish whereas the interlamellar distance decreased. In the liver, the area occupied by lipid droplets and size of hepatocytes showed significantly higher values after 24-h of exposure. The percentage of abnormal renal tubules was higher in fish exposed to Pb, exhibiting a time-dependent increase. These variations in histopathological biomarkers permit the definition of the overall response of R. quelen to Pb and the potential usefulness in the monitoring of Pb contamination.

  2. Acute toxicity of alpha-cypermethrin to guppy (Poecilia reticulata, Pallas, 1859).

    PubMed

    Yilmaz, Mehmet; Gül, Ali; Erbaşli, Kazim

    2004-07-01

    Alpha-cypermethrin is a synthetic pyrethroid insecticide used to control pests in domestic, industrial and agricultural situations. Adult male guppy fish (Poecilia reticulata standard test species) were selected for the bioassay experiments. The experiments were performed in four series and the 96-h LC50 value was determined for guppies. The acute toxicity experiments were carried out by static method and behavioral changes in guppies were determined for each alpha-cypermethrin (98% technical grade) concentration. Data obtained from the alpha-cypermethrin investigation were evaluated by the use of probit analysis statistical method and the 96-h LC50 value for guppy was estimated as 9.43 microg/l.

  3. Acute toxicity of fire-retardant and foam-suppressant chemicals to yalella azteca (Saussure)

    USGS Publications Warehouse

    McDonald, Susan F.; Hamilton, Steven J.; Buhl, Kevin J.; Heisinger, James F.

    1997-01-01

    Acute toxicity tests were conducted with Hyalella azteca Saussure (an amphipod) exposed in soft and hard waters to three fire retardants (Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F) and two foam suppressants (Phos-Chek WD-881 and Silv-Ex). The chemicals were slightly to moderately toxic to amphipods. The most toxic chemical to amphipods in soft and hard water was Phos-Chek WD-881 (96-h mean lethal concentration [LC50] equal to 10 mg/L and 22 mg/L, respectively), and the least toxic chemical to amphipods in soft water was Fire-Trol GTS-R (96-h LC50 equal to 127 mg/L) and in hard water was Fire-Trol LCG-R (96-h LC50 equal to 535 mg/L). Concentrations of ammonia in tests with the three fire retardants and both water types were greater than reported LC50 values and probably were the major toxic component. Estimated un-ionized ammonia concentrations near the LC50 were frequently less than the reported LC50 ammonia concentrations for amphipods. The three fire retardants were more toxic in soft water than in hard water even though ammonia and un-ionized ammonia concentrations were higher in hard water tests than in soft water tests. The accidental entry of fire-fighting chemicals into aquatic environments could adversely affect aquatic invertebrates, thereby disrupting ecosystem function.

  4. Larvicidal and Histopathological Effects of Cassia siamea Leaf Extract against Culex quinquefasciatus

    PubMed Central

    Jiraungkoorskul, Kanitta; Jiraungkoorskul, Wannee

    2015-01-01

    A traditional Thai medicinal extract from Cassia siamea was evaluated with respect to its larvicidal properties by determining the median lethal concentration (LC50) at 24, 48, 72 and 96 h against the fourth instar larvae of Culex quinquefasciatus, which is a carrier of mosquito-borne diseases, by studying the histopathological alterations. The 24, 48, 72 and 96 h LC50 values were 394.29, 350.24, 319.17 and 272.42 ppm, respectively. The histopathological lesions after exposure to 25% of the 24-h LC50 were observed primarily in the midgut of the larva. Lesions with edema, swelling, and deformation or elongation of the epithelial cells were observed. Moreover, cells protruding into the lumen and absent microvilli were also found in some areas. The present study reveals that aqueous C. siamea leaf extracts have natural biopesticide properties. PMID:26868707

  5. Acute and sub-lethal response to mercury in Arctic and boreal calanoid copepods.

    PubMed

    Overjordet, Ida Beathe; Altin, Dag; Berg, Torunn; Jenssen, Bjørn Munro; Gabrielsen, Geir Wing; Hansen, Bjørn Henrik

    2014-10-01

    Acute lethal toxicity, expressed as LC50 values, is a widely used parameter in risk assessment of chemicals, and has been proposed as a tool to assess differences in species sensitivities to chemicals between climatic regions. Arctic Calanus glacialis and boreal Calanus finmarchicus were exposed to mercury (Hg(2+)) under natural environmental conditions including sea temperatures of 2° and 10°C, respectively. Acute lethal toxicity (96 h LC50) and sub-lethal molecular response (GST expression; in this article gene expression is used as a synonym of gene transcription, although it is acknowledged that gene expression is also regulated, e.g., at translation and protein stability level) were studied. The acute lethal toxicity was monitored for 96 h using seven different Hg concentrations. The sub-lethal experiment was set up on the basis of nominal LC50 values for each species using concentrations equivalent to 50, 5 and 0.5% of their 96 h LC50 value. No significant differences were found in acute lethal toxicity between the two species. The sub-lethal molecular response revealed large differences both in response time and the fold induction of GST, where the Arctic species responded both faster and with higher mRNA levels of GST after 48 h exposure. Under the natural exposure conditions applied in the present study, the Arctic species C. glacialis may potentially be more susceptible to mercury exposure on the sub-lethal level.

  6. Evaluation of the genotoxic and cytotoxic effects of glyphosate-based herbicides in the ten spotted live-bearer fish Cnesterodon decemmaculatus (Jenyns, 1842).

    PubMed

    Vera-Candioti, Josefina; Soloneski, Sonia; Larramendy, Marcelo L

    2013-03-01

    Mortality, genotoxicity, and cytotoxicity of the 48% glyphosate-based formulations Panzer and Credit(®) were evaluated on Cnesterodon decemmaculatus (Jenyns, 1842) (Pisces, Poeciliidae) under laboratory conditions. Induction of micronuclei (MN) and alterations in the erythrocytes:erythroblasts ratio were employed as end points for genotoxicity and cytotoxicity, respectively. For Panzer(®), mean values of 16.70 and 15.68 mg/L were determined for LC(50) at 24 and 96 h, respectively, and these concentrations reached mean values of 98.50 and 91.73 mg/L for Credit(®). LC(50) values decreased as a negative linear function of Panzer(®) exposure time within the 0-96 h period, but not for Credit(®). LC(50) values indicated that the fish were more sensitive to Panzer(®) than to Credit(®). Both 3.9 and 7.8 mg/L of Panzer(®) increased MN frequency at 48 and 96 h of treatment. When fish were exposed to Credit(®), an increased frequency of MN over control values was found after 96 h for all concentrations assayed, but not after 48 h. No cellular cytotoxicity was found after Panzer(®) and Credit(®) treatment, regardless of both the concentration and the sampling time. Furthermore, our results demonstrated that Panzer(®) and Credit(®) should be considered as glyphosate-based commercial formulations with genotoxic but not cytotoxic effect properties.

  7. Toxicity of perfluorooctane sulfonate and perfluorooctanoic acid to plants and aquatic invertebrates.

    PubMed

    Li, Mei-Hui

    2009-02-01

    Acute toxicities of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were tested on four freshwater species and three plant species. PFOS was more toxic than PFOA for all species tested in this study. Similar time-response patterns of PFOS and PFOA toxicity were observed for each tested species. Values of the 48-h LC(50) of PFOS for all test species ranged from 27 to 233 mg/L and values of the 96-h LC(50) for three of the species ranged from 10 to 178 mg/L. Values of the 48-h LC(50) of PFOA for all test species ranged from 181 to 732 mg/L and values of the 96-h LC(50) for three of the species ranged from 337 to 672 mg/L. The most sensitive freshwater species to PFOS was green neon shrimp (Neocaridina denticulate) with a 96-h LC(50) of 10 mg/L. Of the aquatic organisms tested, the aquatic snail (Physa acuta) always has the highest resistance to PFOS or PFOA toxicity over each exposure period. Both PFOS and PFOA had no obvious adverse effect on seed germination for all three plant species. Five-day EC(50) of root elongation was more sensitive to LC(50) of seed germination in this study. Based on EC(10), EC(50), and NOECs, the 5-day root elongation sensitivity of test plants to both PFOS and PFOA was in the order of lettuce (Lactuca sativa) > pakchoi (Brassica rapa chinensis) > cucumber (Cucumis sativus). Based on the results of this study and other published literature, it is suggested that current PFOS and PFOA levels in freshwater may have no acute harmful ecological impact on the aquatic environment. However, more research on the long-term ecological effects of PFOS and PFOA on aquatic fauna are needed to provide important information to adequately assess ecological risk of PFOS and PFOA.

  8. Toxicity of perfluorooctane sulfonate and perfluorooctanoic acid to plants and aquatic invertebrates.

    PubMed

    Li, Mei-Hui

    2009-02-01

    Acute toxicities of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were tested on four freshwater species and three plant species. PFOS was more toxic than PFOA for all species tested in this study. Similar time-response patterns of PFOS and PFOA toxicity were observed for each tested species. Values of the 48-h LC(50) of PFOS for all test species ranged from 27 to 233 mg/L and values of the 96-h LC(50) for three of the species ranged from 10 to 178 mg/L. Values of the 48-h LC(50) of PFOA for all test species ranged from 181 to 732 mg/L and values of the 96-h LC(50) for three of the species ranged from 337 to 672 mg/L. The most sensitive freshwater species to PFOS was green neon shrimp (Neocaridina denticulate) with a 96-h LC(50) of 10 mg/L. Of the aquatic organisms tested, the aquatic snail (Physa acuta) always has the highest resistance to PFOS or PFOA toxicity over each exposure period. Both PFOS and PFOA had no obvious adverse effect on seed germination for all three plant species. Five-day EC(50) of root elongation was more sensitive to LC(50) of seed germination in this study. Based on EC(10), EC(50), and NOECs, the 5-day root elongation sensitivity of test plants to both PFOS and PFOA was in the order of lettuce (Lactuca sativa) > pakchoi (Brassica rapa chinensis) > cucumber (Cucumis sativus). Based on the results of this study and other published literature, it is suggested that current PFOS and PFOA levels in freshwater may have no acute harmful ecological impact on the aquatic environment. However, more research on the long-term ecological effects of PFOS and PFOA on aquatic fauna are needed to provide important information to adequately assess ecological risk of PFOS and PFOA. PMID:18461560

  9. The interactive effects of essential ions and salinity on the survival of Mysidopsis bahia in 96-H acute toxicity tests of effluents discharged to marine and estuarine receiving waters

    SciTech Connect

    Douglas, W.S.; Horne, M.T.

    1997-10-01

    The importance of salinity in whole effluent toxicity tests using marine organisms has been acknowledged in most testing protocols. However, little if any attention has been given to the specific effects of alteration of the ionic composition of seawater solutions to the test organism. The presence of persistent toxicity in effluents with no apparent toxic agents prompted examination of the potential influence of essential ions on the survival of the opossum shrimp, Mysidopsis bahia, a common effluent toxicity indicator organism. Through stepwise additions of ionic salts to deionized water, the minimum complement of salts to maintain survival of M. bahia during 96-h exposures was determined to be Ca, Mg, K, Br, Na, and Cl. The toxicity curves for Ca, Mg, K, and Br were then determined across test salinity ranging from 10 to 35 parts per thousand. These curves for Ca, Mg, and K revealed that there are significant negative effects on survival when the essential ions are present in either low or high concentrations relative to the levels in natural seawater. Although there were no statistically detectable effects of Br on organism survival over the concentration range tested (5--480 mg/L). Br toxicity at concentrations less than 5 mg/L and greater than 700 mg/L have been shown in other studies. In addition, the tolerance ranges for K, Ca, and Mg were shown to shift significantly with changes in salinity, with lower salinity causing an apparent decrease in tolerance to an excess of essential ions. Tests with toxic effluents from five industrial and municipal sources revealed that adjustment of the ionic balance prior to testing reduced or eliminated toxicity in four of the five whole effluents tested. Suggestions for integrating this information into biomonitoring programs and toxicity identification evaluations are presented.

  10. Acute toxicity of 31 different nanoparticles to zebrafish (Danio rerio) tested in adulthood and in early life stages – comparative study

    PubMed Central

    Kovrižnych, Jevgenij A.; Zeljenková, Dagmar; Rollerová, Eva; Szabová, Elena; Wimmerová, Soňa

    2013-01-01

    At present, nanoparticles are beginning to influence our lives in many ways and understanding the environmental health and safety aspect of nanomaterials has become a crucial issue. The aim of the work was to assess and compare the acute toxicity of 31 different nanomaterials to fish mature individuals Danio rerio with that to fish early life stages on using evaluation of the 48- and 96- hour LC50 values. A further aim was to evaluate teratogenicity of the nanoparticles tested to fish eggs. The nanoparticles tested were: 8 pure metals, 10 metal oxides, 5 other metal compounds and their mixtures, 2 silicon compounds, 3 calcium compounds, and 3 carbon compounds. Using 48-h and 96-h tests of acute toxicity (according to OECD 203), we evaluated mortality data, LC50 values, occurrence of malformations, as well as hatching time. In our study, 6 kinds of nanoparticles – calcium oxide, copper, copper in the form of oxide and CuZnFe4O4, magnesium oxide, and nickel – caused cumulative mortality. Two kinds of nanoparticles – copper and silver – were toxic for fish with LC50 values of approximately 3 mg/L. We did not observe marked differences between the 48-hour and 96-hour acute toxicity LC50 values, yet the possibility to evaluate hatching time in the 96-h acute fish toxicity test seems to be an advantage against that of the 48-hour toxicity. PMID:24179431

  11. Toxicity assessment and vitellogenin expression in zebrafish (Danio rerio) embryos and larvae acutely exposed to bisphenol A, endosulfan, heptachlor, methoxychlor and tetrabromobisphenol A.

    PubMed

    Chow, Wing Shan; Chan, Winson Ka-Lun; Chan, King Ming

    2013-07-01

    Organochlorine pesticides and brominated flame retardants, such as tetrabromobisphenol A and polybrominated diphenyl ethers, pose an environmental hazard owing to their persistence, low solubility and estrogenic effects, and concerns have been raised regarding their effects on aquatic biota. In the present study, zebrafish embryos and larvae were used as a model to investigate the sublethal and lethal effects of three different organochlorine pesticides, namely methoxychlor, endosulfan and heptachlor, as well as the flame retardant tetrabromobisphenol A, and its precursor compound bisphenol A. Preliminary data for chemical exposure tests were obtained by determining the 96 h median effective concentration EC50 (hatching rate) and 96 h median lethal concentration LC50 . Quantitative polymerase chain reaction was used to investigate the gene expression levels of the biomarker vitellogenin (vtg1) after 96 h exposures to 10, 25, 50 and 75% of the 96 h EC50 value for embryos and 96 h LC50 value for larvae. The use of vtg1 mRNA induction in zebrafish embryos and larvae was found to be a sensitive biomarker of exposure to these organic compounds, and was helpful in elucidating their adverse effects and setting water quality guidelines.

  12. Toxicity of three oil spill remediation techniques to the Australian bass Macquaria novemaculeata.

    PubMed

    Cohen, A M; Nugegoda, D

    2000-10-01

    Australian bass, Macquaria novemaculeata, were exposed to the water accommodated fraction (WAF) of Bass Strait crude oil, dispersed crude oil, burnt crude oil, and 4-chlorophenol. The WAF of dispersed crude oil was the most toxic treatment with 96-h LC(50) values of 7. 15% (7.94% upper and 6.42% lower 95% CI) and 7.45% (8.26% upper and 6.71% lower 95% CI). The WAF of crude oil was less toxic, with 96-h LC(50) values of 43.72% (49.21% upper and 38.87% lower 95% CI) and 45.87% (51.51% upper and 40.97% lower 95% CI). The WAF of burnt crude oil was the least toxic treatment with 96-h LC(50) values of 49.81% (63.33% upper and 39.44% lower 95% CI) and 47.28% (59.72% upper and 37.62% lower 95% CI). Sublethal toxicity of the crude oil WAF and burnt crude oil WAF was observed at dilutions seven to eight times less than in the dispersed crude oil WAF.

  13. Acute and sub-lethal toxicity of landfill leachate towards two aquatic macro-invertebrates: demonstrating the remediation potential of air stripping.

    PubMed

    Bloor, M C; Banks, C J

    2005-10-01

    A specific leachate that contained 1.036 mg l(-1) of 2-chlorobiphenyl was used in the study (255 mg l(-1) COD and 133 mg l(-1) BOD5). Bench scale (20 l) air stripping trials were used to simulate on a small-scale the treatment potential of this method. Air stripping effectively reduced the leachates COD concentration. Regardless of the volume of air supplied (1-5 l of air per minute) the leachates COD reached a <50 mg l(-1) equilibrium after 96-h exposure, however, increasing the volume of air accelerated the process. In untreated leachate, the LC50 for Asellus aquaticus was 57% v/v leachate in deionised water and 5% for Gammarus pulex (96-h, static LC50 tests without nutrition and oxygen depleting conditions). After being exposed to air stripping, these values rose from 90% to below the LC50 threshold for Asellus when 1-5 l of air per minute were applied and 30-90% for Gammarus. Furthermore, in sub-lethal concentrations of air stripped leachate (leachate that had been exposed to 5-l of air per minute for 96-h) the population dynamics of both test species remained unaltered.

  14. Effects of triclosan on marine benthic and epibenthic organisms.

    PubMed

    Perron, Monique M; Ho, Kay T; Cantwell, Mark G; Burgess, Robert M; Pelletier, Marguerite C

    2012-08-01

    Triclosan is an antimicrobial compound that has been widely used in consumer products such as toothpaste, deodorant, and shampoo. Because of its widespread use, triclosan has been detected in various environmental media, including wastewater, sewage sludge, surface waters, and sediments. Triclosan is acutely toxic to numerous aquatic organisms, but very few studies have been performed on estuarine and marine benthic organisms. For whole sediment toxicity tests, the sediment-dwelling estuarine amphipod, Ampelisca abdita, and the epibenthic mysid shrimp, Americamysis bahia, are commonly used organisms. In the present study, median lethal concentration values (LC50) were obtained for both of these organisms using water-only and whole sediment exposures. Acute 96-h water-only toxicity tests resulted in LC50 values of 73.4 and 74.3 µg/L for the amphipod and mysid, respectively. For the 7-d whole sediment toxicity test, LC50 values were 303 and 257 mg/kg (dry wt) for the amphipod and mysid, respectively. Using equilibrium partitioning theory, these whole sediment values are equivalent to interstitial water LC50 values of 230 and 190 µg/L for the amphipod and mysid, respectively, which are within a threefold difference of the observed 96-h LC50 water-only values. Triclosan was found to accumulate in polychaete tissue in a 28-d bioaccumulation study with a biota-sediment accumulation factor of 0.23 kg organic carbon/kg lipid. These data provide some of the first toxicity data for triclosan with marine benthic and epibenthic species while also indicating a need to better understand the effects of other forms of sediment carbon, triclosan ionization, and organism metabolism of triclosan on the chemical's behavior and toxicity in the aquatic environment.

  15. Sensitivities of Australian and New Zealand amphipods to copper and zinc in waters and metal-spiked sediments.

    PubMed

    King, Catherine K; Gale, Sharyn A; Hyne, Ross V; Stauber, Jenny L; Simpson, Stuart L; Hickey, Christopher W

    2006-06-01

    The sensitivities of eight benthic amphipods, Chaetocorophium cf. lucasi, Corophium colo, Grandidierella japonica, Hyale crassicornis, Hyale longicornis, Melita awa, Melita matilda and Melita plumulosa, to copper and zinc in water-only and whole-sediment toxicity tests were compared. Whole-sediment tests used copper- (1300 mg/kg) and zinc- (4000 mg/kg) spiked sediments after equilibration for sufficient time to produce pore water and overlying water concentrations below the lowest observable effect concentrations of water-only exposures. Survival of adults (after 10 d) and juveniles (after 96 h), and the metal concentrations in the body tissues of adults, were determined at the end of the tests. Two epibenthic amphipods from the genus Melita were the most sensitive species to aqueous copper and zinc, with a 96-h LC50 value of 120 microg Cu/l for both M. awa and M. plumulosa juveniles, and a 96-h LC50 value of 640 microg Zn/l for juveniles of M. plumulosa. Juvenile amphipods (7-d old) were more sensitive than adult amphipods (>30-d old) in both water-only and whole-sediment tests, with adult-LC50/juvenile-LC50 ratios in water-only tests ranging from 1.2 to l.5 for copper and 1 to 1.4 for zinc. All species except C. colo, C. cf. lucasi and M. matilda were sensitive to the copper-spiked sediment, with survival between 14% and 74% of controls. Similarly, all species except C. colo and G. japonica, showed a response to the zinc-spiked sediment (26-81% of control survival). The epibenthic amphipods were more sensitive than the infaunal tube-dwelling amphipods and are recommended as test species.

  16. Acute toxicity of a commercial glyphosate formulation on European sea bass juveniles (Dicentrarchus labrax L.): gene expressions of heme oxygenase-1 (ho-1), acetylcholinesterase (AChE) and aromatases (cyp19a and cyp19b).

    PubMed

    Prevot-D'Alvise, N; Richard, S; Coupé, S; Bunet, R; Grillasca, J P

    2013-12-31

    Acute toxicity of Roundup, a commercial glyphosate--based herbicide, was evaluated in a teleost marine fish, the European sea bass, after 96 h of exposure. The LC50 96-h value of Roundup was 529 mg/L. Juveniles (Dicentrarchus labrax L.) were exposed to a sublethal concentration (35% of the LC50, i.e. 193 mg/L) of Roundup for 96-h. The study of heme oxygenase-1 (ho-1) gene expression was performed in four tissues (liver, gills, brain and gonads) and highlighted the disruption of antioxidant defence system. Results showed that ho-1 mRNA levels in liver and gills significantly decreased (p<0.001 and p<0.01 respectively) in fish exposed to 193 mg/L of Roundup, whereas in brain and gonads, ho-1 mRNA level was not altered. The analysis of acetylcholinesterase expression was used to evaluate the overall neurotoxicity of the herbicide and aromatase genes to assess the alteration of the endocrine system. Results showed that AChE and cyp19b gene transcriptions significantly increased (p<0.01) in brain of sea bass, whereas aromatase gene expression (cyp19a) in gonads was not significantly altered. Our results showed complex tissue-specific transcriptional responses after 96 h of exposure to a sublethal concentration. All these disruptions confirmed the deleterious effects of this glyphosate-based herbicide in a marine species.

  17. Study of toxicity and bioaccumulation of copper in the silver sea bream Sparus sarba

    SciTech Connect

    Wong, P.P.K.; Chu, L.M.; Wong, C.K.

    1999-05-01

    The toxicity and bioaccumulation of copper were studied in fingerlings (mean body weight = 9.4 {+-} 2.1 g) and subadults (mean body weight = 85.5 {+-} 27.1 g) of the silver sea bream Sparus sarba. Test fish were obtained from local fish culture sites. Static tests over 96 h showed that subadults were not more tolerant to copper than the much smaller fingerlings. The 24-h, 48-h, 72-h, and 96-h LC50 for fingerlings were 2.01 mg Cu L{sup {minus}1}, 1.28 mg Cu L{sup {minus}1}, 1.17 mg Cu L{sup {minus}1}, and 1.03 mg Cu L{sup {minus}1}, respectively. The values for subadults were 2.36 mg Cu L{sup {minus}1}, 1.52 mg Cu L{sup {minus}1}, 1.34 mg Cu L{sup {minus}1}, and 1.24 mg Cu L{sup {minus}1}, respectively. Copper concentrations corresponding to 13%, 25%, and 40% of the 96-h LC50 value were used to study the effects of copper exposure on the growth rate of S. sarba in 30-d bioassays. The growth rate of fingerlings was higher than that of subadults by approximately a hundred-fold. For both fingerlings and subadults, reduced growth was observed at 0.15 mg Cu L{sup {minus}1} ({approximately}40% of the 96-h LC50 value). Growth appeared to be a more sensitive endpoint for toxicity tests than mortality. Fish exposed to copper for 30 d contained more copper than control animals. The highest copper concentrations for both fingerlings and subadults were found in the intestine. The order of copper concentration was intestine > liver > gonad > gills, skin and muscle.

  18. Relative toxicity of the components of the original formulation of Roundup to five North American anurans.

    PubMed

    Moore, Lindsay J; Fuentes, Latice; Rodgers, John H; Bowerman, William W; Yarrow, Greg K; Chao, Wayne Y; Bridges, William C

    2012-04-01

    The responses of five North American frog species that were exposed in an aqueous system to the original formulation of Roundup were compared. Carefully designed and un-confounded laboratory toxicity tests are crucial for accurate assessment of potential risks from the original formulation of Roundup to North American amphibians in aquatic environments. The formulated mixture of this herbicide as well as its components, isopropylamine (IPA) salt of glyphosate and the surfactant MON 0818 (containing polyethoxylated tallowamine (POEA)) were separately tested in 96 h acute toxicity tests with Gosner stage 25 larval anurans. Rana pipiens, R. clamitans, R. catesbeiana, Bufo fowleri, and Hyla chrysoscelis were reared from egg masses and exposed to a series of 11 concentrations of the original formulation of Roundup herbicide, nine concentrations of MON 0818 and three concentrations of IPA salt of glyphosate in static (non-renewal) aqueous laboratory tests. LC50 values are expressed as glyphosate acid equivalents (ae) or as mg/L for MON 0818 concentrations for comparison between the formulation and components. R. pipiens was the most sensitive of five species with 96 h-LC50 values for formulation tests, for the five species, ranging from 1.80 to 4.22 mg ae/L, and MON 0818 exposures with 96 h-LC50 values ranging from 0.68 to 1.32 mg/L. No significant mortality was observed during exposures of 96 h for any of the five species exposed to glyphosate IPA salt at concentrations up to 100 times the predicted environmental concentration (PEC). These results agree with previous studies which have noted that the surfactant MON 0818 containing POEA contributes the majority of the toxicity to the herbicide formulations for fish, aquatic invertebrates, and amphibians. These study results suggest that anurans are among the most sensitive species, and emphasize the importance of testing the herbicide formulation in addition to its separate components to accurately characterize the

  19. Relative toxicity of the components of the original formulation of Roundup to five North American anurans.

    PubMed

    Moore, Lindsay J; Fuentes, Latice; Rodgers, John H; Bowerman, William W; Yarrow, Greg K; Chao, Wayne Y; Bridges, William C

    2012-04-01

    The responses of five North American frog species that were exposed in an aqueous system to the original formulation of Roundup were compared. Carefully designed and un-confounded laboratory toxicity tests are crucial for accurate assessment of potential risks from the original formulation of Roundup to North American amphibians in aquatic environments. The formulated mixture of this herbicide as well as its components, isopropylamine (IPA) salt of glyphosate and the surfactant MON 0818 (containing polyethoxylated tallowamine (POEA)) were separately tested in 96 h acute toxicity tests with Gosner stage 25 larval anurans. Rana pipiens, R. clamitans, R. catesbeiana, Bufo fowleri, and Hyla chrysoscelis were reared from egg masses and exposed to a series of 11 concentrations of the original formulation of Roundup herbicide, nine concentrations of MON 0818 and three concentrations of IPA salt of glyphosate in static (non-renewal) aqueous laboratory tests. LC50 values are expressed as glyphosate acid equivalents (ae) or as mg/L for MON 0818 concentrations for comparison between the formulation and components. R. pipiens was the most sensitive of five species with 96 h-LC50 values for formulation tests, for the five species, ranging from 1.80 to 4.22 mg ae/L, and MON 0818 exposures with 96 h-LC50 values ranging from 0.68 to 1.32 mg/L. No significant mortality was observed during exposures of 96 h for any of the five species exposed to glyphosate IPA salt at concentrations up to 100 times the predicted environmental concentration (PEC). These results agree with previous studies which have noted that the surfactant MON 0818 containing POEA contributes the majority of the toxicity to the herbicide formulations for fish, aquatic invertebrates, and amphibians. These study results suggest that anurans are among the most sensitive species, and emphasize the importance of testing the herbicide formulation in addition to its separate components to accurately characterize the

  20. Effect of low salinity on the yellow clam Mesodesma mactroides.

    PubMed

    Carvalho, Y B M; Romano, L A; Poersch, L H S

    2015-01-01

    The aim of this study was to determine the lethal salinity (LC50) for the yellow clam Mesodesma mactroides (Bivalvia: Mesodesmatidae) and identify histopathological alterations that could be used to diagnose structural changes in clam tissue. Clams in two size classes (adults and juveniles) were placed in 10 L chambers and exposed to salinities of 35, 30, 25, 20, 15, 10, and 5 g/L. There were triplicate chambers with seven clams each for each salinity. The LC50 values for a 48 h exposure were 6.5 g/L and 5.7 g/L for adults and juveniles, respectively. For a 96 h exposure, the LC50 values were 10.5 g/L for adults and 8.8 g/L for juveniles. The histological examination of yellow clams exposed to 10 g/L for 96 h showed intercellular oedema and necrotic foci in the epithelium of the digestive gland and occlusion of the lumen of the digestive gland. In conclusion, M. mactroides can be characterised as a moderately euryhaline species, tolerating salinities from 35 to 15 g/L.

  1. Individual and Joint Acute Toxicities of Selected Insecticides Against Bombyx mori (Lepidoptera: Bombycidae).

    PubMed

    Yu, R X; Wang, Y H; Hu, X Q; Wu, S G; Cai, L M; Zhao, X P

    2016-02-01

    As widely used pesticides, organophosphate, pyrethroid, and neonicotinoid insecticides have different modes of action. In the present study, we evaluated individual and joint acute toxicities of two organophosphates, two pyrethroids, and two neonicotinoids against the second-instar silkworm by feeding silkworm with the insecticide-treated mulberry leaves. The 96-h lethal concentration 50 (LC(50)) values of chlorpyrifos, acephate, imidacloprid, thiamethoxam, cypermethrin, and deltamethrin against silkworm were 3.45 (2.95-4.31), 44.45 (39.34-48.56), 1.27 (1.19-1.35), 2.38 (2.19-2.54), 0.36 (0.30-0.43), and 0.037 (0.033-0.041) mg/liter, respectively. Moreover, the 96-h LC(50) values of 50:50 binary mixtures of insecticides against silkworm ranged from 0.048 (0.043-0.054) to 3.52 (2.09-4.51) mg/liter. In addition, the combination coefficient (Q) values of all tested mixtures ranged from 0.36 to 3.37. According to the obtained Q values, the binary mixture of deltamethrin-chlorpyrifos showed antagonistic effects at 96-h interval, while the other binary mixtures had additive effects. Taken together, our results provided valuable guidelines in assessing the ecological risk of these insecticide mixtures against silkworm.

  2. Toxicity and bioaccumulation of copper in Limnodrilus hoffmeisteri under different pH values: Impacts of perfluorooctane sulfonate.

    PubMed

    Meng, Lingjun; Yang, Shaogui; Feng, Mingbao; Qu, Ruijuan; Li, Yong; Liu, Jiaoqin; Wang, Zunyao; Sun, Cheng

    2016-03-15

    Aquatic oligochaete Limnodrilus hoffmeisteri (L. hoffmeisteri) has been commonly used as a lethal and/or sub-lethal toxicological model organism in ecological risk assessments in contaminated water environments. In this study, experiments were conducted to investigate the potential toxic effects of copper (Cu(II)) with or without perfluorooctane sulfonate (PFOS) under different pH values (6.0, 7.0 and 8.0) on LC50, bioaccumulation, and oxidative stress biomarkers in L. hoffmeisteri after 3 and 7 days. The LC50 values of Cu(II) decreased with the increasing pH and the addition of PFOS. After each exposure, increasing bioaccumulation of Cu(II) in L. hoffmeisteri was observed in the combined exposure treatments, whereas the bioaccumulation of PFOS decreased. Moreover, the activity of superoxide dismutase, the level of glutathione, and the content of malondialdehyde were significantly altered after these exposures, possibly indicating that the bioaccumulation of Cu(II) and PFOS caused adverse effects on antioxidant defenses of L. hoffmeisteri. The integrated biomarker response index, indicates that the combined effect was proposed as synergism, which is coincided with the results of toxic unit. Moreover, this work showed that aquatic environment may become more livable when water conditions changed from acidic to near-neutral or alkaline.

  3. Effects of chloride, calcium, and dissolved organic carbon on silver toxicity: Comparison between rainbow tout and fathead minnows

    SciTech Connect

    Bury, N.R.; Galvez, F.; Wood, C.M.

    1999-01-01

    The effects of independently altering chloride, calcium, and dissolved organic carbon (DOC) on the toxicity of silver were compared between rainbow trout (Oncorhynchus mykiss) and fathead minnows (Pimephales promelas). The 96-h median lethal concentration toxicity tests for both species were performed under the same conditions, within the same containers. In addition, the effect of altering [Cl{sup {minus}}] on silver-induced perturbations to body Na{sup +} influx and gill silver load was studied. Toxicity tests were conducted in synthetic soft water (50 {micro}M Na{sup +}, 50 {micro}M Cl{sup {minus}}, 50 {micro}M Ca{sup 2+}, 0.3 mg DOC/L). The [Cl{sup {minus}}], [Ca{sup 2+}], and [DOC] were adjusted by the addition of NaCl, CaNO{sub 3}, or humic acid, respectively. On the basis of total silver, increasing [Cl{sup {minus}}] over a range of 50 {micro}M to 1,500 {micro}M resulted in a 4.3-fold increase in the 96-h LC50 values (decrease in toxicity) for rainbow trout, but did not significantly affect the 96-h LC50 values for fathead minnows. Increasing water [Ca{sup 2+}] (from 50 to 2,000 {micro}M) had only a small influence on the 96-h LC50 values in both species. If the 96-h LC50 values are calculated on the basis of ionic silver, Ag{sup +}, then, in the case of rainbow trout, toxicity correlates to Ag{sup +}. However, this correlation does not exist for fathead minnows. Increasing [Cl{sup {minus}}] did not affect the degree of perturbation of Na{sup +} influx during acute exposure (first 4 h) to 8 {micro}g Ag/L in either species, nor did it affect the whole-body silver uptake rates, but it did reduce the gill silver load. These results demonstrate that differences exist in the way in which water chemistry ameliorates silver toxicity between rainbow trout and fathead minnows.

  4. Evaluation of the acute toxicity of profenofos and its effects on the behavioral pattern of fingerling common carp (Cyprinus carpio L., 1758).

    PubMed

    Ismail, Muhammad; Ali, Rahat; Ali, Tayyaba; Waheed, Usman; Khan, Qaiser Mahmood

    2009-05-01

    Profenofos, an organophosphate insecticide is acetylcholinesterase inhibitor that has the potential to contaminate the ground water. The 96 h LC(50) value of profenofos was determined in 3-month-old fingerling common carp (Cyprinus carpio) with a body weight 1.04 +/- 0.25 g and a body length 4.25 +/- 0.75 cm at 26 +/- 1 degrees C temperature. Trimmed Spearman-Karber (TSK) software was used for the statistical analysis, which calculated the LC(50) value as 62.4 microg/L for three replicates of the assay. The behavioral responses of fish exposed to profenofos included loss of balance, moving in spiral fashion with sudden jerky movements, lying on their sides and rapid flapping of the operculum with the mouth open. PMID:19242633

  5. Correlation between heavy metal acute toxicity values in Daphnia magna and fish

    SciTech Connect

    Khangarot, B.S.; Ray, P.K.

    1987-04-01

    In the toxicant bioassays, invertebrates with special reference to aquatic arthropod species have been of recent interest as test models due to the need for developing nonmammalian tests system. The cladoceran Daphnia magna bioassays have several practical advantages. D. magna has been used as a useful test species and its sensitivity to environmental pollutants have been recognized as a general representative of other freshwater zooplankton species. The objectives of this study were to determine the acute toxicity of various heavy metals to Daphnia magna for 48 h of exposure and to compare these values with the existing LC50 values for rainbow trout (Salmo gairdneri); which is commonly used as a test animal in aquatic bioassay studies.

  6. Valuing Essays: Essaying Values

    ERIC Educational Resources Information Center

    Badley, Graham

    2010-01-01

    The essay regularly comes under attack. It is criticised for being rigidly linear rather than flexible and reflective. I first challenge this view by examining reasons why the essay should be valued as an important genre. Secondly, I propose that in using the essay form students and academics necessarily exemplify their own critical values. Essays…

  7. Influence of water quality and age on nickel toxicity to fathead minnows (Pimephales promelas).

    PubMed

    Hoang, Tham Chung; Tomasso, Joseph R; Klaine, Stephen J

    2004-01-01

    This research characterized the effects of water quality and organism age on the toxicity of nickel (Ni) to fathead minnows (Pimephales promelas) to facilitate the accurate development of site-specific water-quality criteria. Nickel sulfate hexahydrate (NiSO4 x 6H2O) was used as the Ni source for performing acute toxicity tests (median lethal concentration after 96-h exposure [96-h LC50]) with < 1-d-old and 28-d-old P. promelas under varying regimes of hardness, pH, alkalinity, and natural organic matter (NOM). The toxicity of Ni was inversely related to water hardness between hardness values of 20 and 150 mg/L (as CaCO3). Below 30 mg/L alkalinity, Ni toxicity was related to alkalinity. The effect of pH was confounded by hardness and the presence of NOM. In the absence of NOM, the toxicity of Ni increased as pH increased at high hardness and alkalinity. In general, 28-d-old fish were less sensitive than < 1-d-old fish to Ni. This lower sensitivity ranged from 12-fold at low hardness and alkalinity (20 and 4 mg/L, respectively) to 5-fold at high hardness and alkalinity (100 and 400 mg/L, respectively). The presence of NOM (10 mg/L as dissolved organic carbon [DOC]) reduced Ni toxicity by up to 50%, but this effect appeared to be saturated above DOC at 5 mg/L. Incubating Ni with the NOM solution from 1 to 17 days had no effect on Ni toxicity. When using multivariate analysis, the 96-h LC50 for Ni was a function of fish age, alkalinity, hardness, and NOM (96-h LC50 = -0.642 + 0.270(fish age) + 0.005(alkalinity) + 0.018(hardness) + 0.138(DOC)). When using this model, we found a strong relationship between measured and predicted 96-h LC50 values (r2 = 0.94) throughout the treatment water qualities. The biotic ligand model (BLM) did not accurately predict Ni toxicity at high or low levels of alkalinity. Results of our research suggest that the BLM could be improved by considering NiCO3 to be bioavailable.

  8. Toxicity of the Herbicide Atrazine: Effects on Lipid Peroxidation and Activities of Antioxidant Enzymes in the Freshwater Fish Channa Punctatus (Bloch)

    PubMed Central

    Nwani, Christopher Ddidigwu; Lakra, Wazir Singh; Nagpure, Naresh Sahebrao; Kumar, Ravindra; Kushwaha, Basdeo; Srivastava, Satish Kumar

    2010-01-01

    The present study was undertaken to evaluate the toxicity and effects of a commercial formulation of the herbicide atrazine (Rasayanzine) on lipid peroxidation and antioxidant enzyme system in the freshwater air breathing fish Channa punctatus. The 12, 24, 48, 72 and 96 h LC50 of atrazine, calculated by probit analysis, were determined to be 77.091, 64.053, 49.100, 44.412 and 42.381 mg·L−1, respectively, in a semi static system with significant difference (p < 0.05) in LC10–90 values obtained for different times of exposure. In addition to concentration and time dependent decrease in mortality rate, stress signs in the form of behavioral changes were also observed in response to the test chemical. In fish exposed for 15 days to different sublethal concentrations of the herbicide (1/4 LC50 = ∼10.600 mg·L−1, 1/8 LC50 = ∼5.300 mg·L−1 and 1/10 LC50 = ∼4.238 mg·L−1) induction of oxidative stress in the liver was evidence by increased lipid peroxidation levels. The antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) responded positively in a concentration dependent pattern, thus, suggesting the use of these antioxidants as potential biomarkers of toxicity associated with contaminations exposure in freshwater fishes. PMID:20948961

  9. Ecotoxicological effects of carbofuran and oxidised multiwalled carbon nanotubes on the freshwater fish Nile tilapia: nanotubes enhance pesticide ecotoxicity.

    PubMed

    Campos-Garcia, Janaína; Martinez, Diego Stéfani T; Alves, Oswaldo L; Leonardo, Antônio Fernando Gervásio; Barbieri, Edison

    2015-01-01

    The interactions of carbon nanotubes with pesticides, such as carbofuran, classical contaminants (e.g., pesticides, polyaromatic hydrocarbons, heavy metals, and dyes) and emerging contaminants, including endocrine disruptors, are critical components of the environmental risks of this important class of carbon-based nanomaterials. In this work, we studied the modulation of acute carbofuran toxicity to the freshwater fish Nile tilapia (Oreochromis niloticus) by nitric acid treated multiwalled carbon nanotubes, termed HNO3-MWCNT. Nitric acid oxidation is a common chemical method employed for the purification, functionalisation and aqueous dispersion of carbon nanotubes. HNO3-MWCNT were not toxic to Nile tilapia at concentrations ranging from 0.1 to 3.0 mg/L for exposure times of up to 96 h. After 24, 48, 72 and 96 h, the LC50 values of carbofuran were 4.0, 3.2, 3.0 and 2.4 mg/mL, respectively. To evaluate the influence of carbofuran-nanotube interactions on ecotoxicity, we exposed the Nile tilapia to different concentrations of carbofuran mixed together with a non-toxic concentration of HNO3-MWCNT (1.0 mg/L). After 24, 48, 72, and 96 h of exposure, the LC50 values of carbofuran plus nanotubes were 3.7, 1.6, 0.7 and 0.5 mg/L, respectively. These results demonstrate that HNO3-MWCNT potentiate the acute toxicity of carbofuran, leading to a more than five-fold increase in the LC50 values. Furthermore, the exposure of Nile tilapia to carbofuran plus nanotubes led to decreases in both oxygen consumption and swimming capacity compared to the control. These findings indicate that carbon nanotubes could act as pesticide carriers affecting fish survival, metabolism and behaviour.

  10. What Value "Value Added"?

    ERIC Educational Resources Information Center

    Richards, Andrew

    2015-01-01

    Two quantitative measures of school performance are currently used, the average points score (APS) at Key Stage 2 and value-added (VA), which measures the rate of academic improvement between Key Stage 1 and 2. These figures are used by parents and the Office for Standards in Education to make judgements and comparisons. However, simple…

  11. Further validation of FETAX: evaluation of the developmental toxicity of five known mammalian teratogens and non-teratogens.

    PubMed

    Bantle, J A; Fort, D J; Rayburn, J R; DeYoung, D J; Bush, S J

    1990-01-01

    The developmental toxicity of five compounds was evaluated with the Frog Embryo Teratogenesis Assay: Xenopus (FETAX). Late Xenopus laevis blastulae were exposed to 5-azacytidine, methotrexate, pseudoephedrine, aspartame, and amaranth for 96 h. Three separate static-renewal assays were conducted for each compound. Based on Teratogenic Index [LC50/EC50 (malformation)] values, types and severity of induced malformations, and embryo growth, 5-azacytidine and methotrexate tested as having strong teratogenic potential. Pseudoephedrine scored as having moderate teratogenic potential, but amaranth and aspartame had little or no teratogenic potential. Results support the use of FETAX for the screening of developmental toxicants.

  12. Low concentrations of metal mixture exposures have adverse effects on selected biomarkers of Xenopus laevis tadpoles.

    PubMed

    Yologlu, Ertan; Ozmen, Murat

    2015-11-01

    Polluted ecosystems may contain mixtures of metals, such that the combinations of metals, even in low concentrations, may cause adverse effects. In the present study, we focused on toxic effects of mixtures of selected metals, the LC50 values, and also their safety limit in aquatic systems imposed by the European legislation using a model organism. Xenopus laevis tadpoles were used as test organisms. They were exposed to metals or their combinations due to 96-h LC50 values. Glutathione S-transferase (GST), glutathione reductase (GR), acetylcholinesterase (AChE), carboxylesterase (CaE), glutathione peroxidase (GPx), and catalase (CAT) levels were evaluated. Metallothionein concentrations were also determined. The LC50s for Cd, Pb, and Cu were calculated as 5.81mg AI/L, 123.05mg AI/L, and 0.85mg AI/L, respectively. Low lethality ratios were observed with unary exposure of each metal in lower concentrations. Double or triple combinations of LC50 and LC50/2 concentrations caused 100% lethality with Cd+Cu and Pb+Cd+Cu mixtures, while the Pb+Cu mixture also caused high lethal ratios. The selected enzyme activities were significantly affected by metals or mixtures, and dose-related effects were determined. The metallothionein levels generally increased as related to concentration in unary metals and mixtures. Acceptable limit values of unary metals and mixtures did not significantly change metallothionein levels. The results suggest that oxidative stress-related mechanisms are involved in the toxicity induced by selected metals with combinations of very low concentrations.

  13. Molluscicidal activity of Ferula asafoetida, Syzygium aromaticum and Carum carvi and their active components against the snail Lymnaea acuminata.

    PubMed

    Kumar, Pradeep; Singh, D K

    2006-06-01

    The molluscicidal activity of dried root latex powder of Ferula asafoetida, flower-bud powder of Syzygium aromaticum and seed powder of Carum carvi against the snail Lymnaea acuminata was studied. The molluscicidal activity of all the three plant products was found to be both time and concentration dependent. The toxicity of S. aromaticum flower-bud powder (96 h LC(50):51.98 mg/l) was more pronounced than that of root latex powder of F. asafoetida (96 h LC(50):82.71 mg/l) and seed powder of C. carvi (96 h LC(50):140.58 mg/l). Ethanol extract was more toxic than other organic extracts. The ethanol extract of S. aromaticum (24h LC(50):83.53 mg/l) was more effective than that of F. asafoetida (24h LC(50):132.31 mg/l) and C. carvi (24h LC(50):130.61 mg/l) in killing the test animals. The 96 h LC(50) of column purified fraction of seed powder of C. carvi was 5.40 mg/l whereas those of flower-bud powder of S. aromaticum and dried root latex powder of F. asafoetida were 7.87 and 9.67 mg/l, respectively. The product of F. asafoetida, S. aromaticum and C. carvi may be used as potent molluscicides.

  14. Preliminary results of laboratory toxicity tests with the mayfly, Isonychia bicolor (Ephemeroptera: Isonychiidae) for development as a standard test organism for evaluating streams in the Appalachian coalfields of Virginia and West Virginia.

    PubMed

    Echols, Brandi Shontia; Currie, Rebecca J; Cherry, Donald S

    2010-10-01

    Selecting the most appropriate test species for sediment and water column assays has been a primary goal for ecotoxicologists. Standard test organisms and established test guidelines exist, but the USEPA-recommended species may not be the most sensitive organisms to anthropogenic inputs. This paper describes preliminary results of toxicity tests with the mayfly, Isonychia bicolor (Ephemeroptera). Results suggested that Isonychia were moderately sensitive to NaCl after 96 h with an average LC(50) value of 3.10 g NaCl per liter. This value decreased after 7 days of exposure, resulting in a mean LC(50) value of 1.73 g NaCl per liter. When exposed to a coal-mine-processed effluent, Isonychia generated LC(50) values that ranged from 13% to 39% effluent. I. bicolor were more sensitive to the coal processing effluent than Ceriodaphnia dubia with conductivity lowest observable effects concentration (LOEC) values for mayfly survivorship that ranged from 1,508 to 4,101 microS/cm, while LOEC values for C. dubia reproduction ranged from 2,132 to 4,240 microS/cm.

  15. Acute toxicities of four metals on the early life stages of the crab Chasmagnathus granulata from Bahía Blanca estuary, Argentina.

    PubMed

    Ferrer, Laura; Andrade, Santiago; Asteasuain, Raúl; Marcovecchio, Jorge

    2006-10-01

    Acute semistatic toxicity tests were carried out for 96 h with first zoeae and young crabs of Chasmagnathus granulata. Survival curves and LC50 (lethal concentration 50, the concentration which produces the death of 50% of the exposed population) indices for copper, zinc, cadmium, and lead were determined. Furthermore, mixture toxicity tests (Cd/Cu and Cd/Zn) with first-stage larvae were also carried out. The LC50-96 h values determined in this study were 1093.4 (881-1319) microg Pb2+ L(-1), 219.2 (188.9-248.9) microg Cu2+ L(-1), 172.1 (141.3-203.6) microg Zn2+ L(-1), and 47.8 (37.9-58.0) microg Cd2+ L(-1) for zoeae I and 130.1 (121.7-139.0) mg Cu2+ L(-1), 51.0 (41.9-61.6) mg Zn2+ L(-1), and 35.7 (30.1-41.9) mg Cd2+ L(-1) for young crabs. The LC50-96 h indices for mixture tests with zoeae I were 260.6 (227.3-286.3) microg Cd2+/Zn2+ L(-1) and 41.3 (37.4-60.7) microg Cd2+/Cu2+ L(-1). Cadmium presented the highest acute toxicity for both stages of the life cycle examined. The toxicity of the metals analyzed followed the order cadmium >zinc>copper>lead. First zoeae were more sensitive than young crabs to acute exposure to all metals analyzed. The young crabs were considered potentially dangerous agents of transference to the associated trophic chain because of their relatively elevated resistance and their capacity to bioaccumulate heavy metals in their tissues. Mixed toxicity tests carried out on first-stage larvae showed different kinds of interactions. Cadmium/copper presented an additive interaction trend while the mixture cadmium/zinc showed an antagonistic interaction. PMID:16098589

  16. Effect of Chlorpyrifos Ethyl on Acetylcholinesterase Activity in Climbing Perch (Anabas testudineus, Bloch, 1972).

    PubMed

    Tam, Nguyen Thanh; Berg, Håkan; Tuyen, Phan Thi Bich; Van Cong, Nguyen

    2015-11-01

    The high use of pesticides in intensive rice farming in the Mekong Delta constitutes a potential hazard to the environment and to people's health. Chlorpyrifos ethyl (CPF) is a commonly used organophosphate (OP) insecticide, but information about its potential negative impacts on the aquatic environment in the Mekong Delta is scarce. Both acute and subacute toxicity tests were performed in a static nonrenewable system to investigate the effects of CPF on brain acetylcholinesterase (AChE) activity in native climbing perch fingerlings (Anabas testudineus, Bloch, 1972). Environmental parameters, such as dissolved oxygen, water temperature, and pH, were similar to field conditions in the Mekong Delta. In a 96-h lethal concentration (LC50) test, fingerlings of climbing perch were randomly exposed to five levels of CPF ranging from 0.8 to 4.5 ppm. Five sublethal levels of CPF (1, 5, 10, 15, and 20 % of the 96-h LC50 value) were tested to assess the sensitivity and recovery of the brain AChE activity in climbing perch fingerlings exposed to CPF. The results showed that CPF were moderately toxic to climbing perch with a 96-h median LC50 of 1.73 ppm. CPF also caused long-term AChE inhibition with 70 % inhibition remaining after 96 h for the four highest test concentrations. The recovery of brain AChE activity in fish placed in CPF-free water was very slow, and after 7 days the brain AChE activity was still significant lower in fish from the four highest concentrations compared with the control. The results from this study indicate that OP insecticides, such as CPF, can have long-lasting sublethal effects on aquatic species in the Mekong Delta. PMID:26135300

  17. Lethal and sublethal toxicity of the antifoulant compound Irgarol 1051 to the mud snail Ilyanassa obsoleta.

    PubMed

    Finnegan, Meaghean C; Pittman, Sherry; DeLorenzo, Marie E

    2009-01-01

    Irgarol 1051 is an algistatic compound used in copper-based antifoulant paints. It is a widespread and persistent pollutant of the estuarine environment. Ilyanassa obsoleta, the Eastern mud snail, is a common intertidal gastropod that inhabits mud flats and salt marshes along the east coast of North America. It is an important inhabitant of the estuarine environment; contributing to nutrient regeneration and regulating microbial processes in the sediments. The toxicity of irgarol to estuarine gastropods has not been previously examined, although they have the potential to be exposed to antifoulants through both aqueous and sediment routes. The objectives of this study were to evaluate irgarol's effects on I. obsoleta survival, reproductive status (imposex occurrence and testosterone levels), chemoreceptive function, and cellular respiration (cytochrome-c oxidase activity). Irgarol was moderately toxic to I. obsoleta; adult aqueous 96-h LC(50) = 3.73 mg/L, larval aqueous 96-h LC(50) = 3.16 mg/L, and adult sediment 10-day LC(50) = 12.21 mg/kg. Larval snails were not significantly more sensitive to irgarol than adult snails. A chronic 45-day aqueous irgarol exposure (0.005-2.5 mg/L) did not induce imposex or affect free-testosterone levels. The 45-day chronic LC(50 )of 1.88 mg/L was significantly lower than the 96-h acute value. A 96-h acute aqueous irgarol exposure (0.375-1.5 mg/L) caused a decrease in normal response to chemosensory cues such as the presence of food or predators. There was a significant increase in cytochrome-c oxidase activity at 2.5 mg/L, which might indicate irgarol's disruption of the mitochondrial membrane and subsequently ATP synthesis. Although the toxicity values determined for I. obsoleta exceeded irgarol concentrations measured in surface waters, results from this toxicity assessment will provide valuable information to environmental resource managers faced with decisions regarding the use and regulation of antifoulant paints in the

  18. Sensitivity and response time of three common Antarctic marine copepods to metal exposure.

    PubMed

    Zamora, Lara Marcus; King, Catherine K; Payne, Sarah J; Virtue, Patti

    2015-02-01

    Understanding the sensitivity of Antarctic marine organisms to metals is essential in order to manage environmental contamination risks. To date toxicity studies conducted on Antarctic marine species are limited. This study is the first to examine the acute effects of copper and cadmium on three common coastal Antarctic copepods: the calanoids Paralabidocera antarctica and Stephos longipes, and the cyclopoid Oncaea curvata. These copepods responded slowly to metal exposure (4-7d) emphasising that the exposure period of 48-96 h commonly used in toxicity tests with temperate and tropical species is not appropriate for polar organisms. We found that a longer 7 d exposure period was the minimum duration appropriate for Antarctic copepods. Although sensitivity to metal exposure varied between species, copper was more toxic than cadmium in all three species. P.antarctica was the most sensitive with 7d LC50 values for copper and cadmium of 20 μg L(-1) and 237 μg L(-1) respectively. Sensitivities to copper were similar for both O. curvata (LC50=64 μg L(-1)) and S. longipes (LC50=56 μg L(-1)), while O. curvata was more sensitive to cadmium (LC50=901 μg L(-1)) than S. longipes (LC50=1250 μg L(-1)). In comparison to copepods from lower latitudes, Antarctic copepods were more sensitive to copper and of similar sensitivity or less sensitive to cadmium. This study highlights the need for longer exposure periods in toxicity tests with slow responding Antarctic biota in order to generate relevant sensitivity data for inclusion in site-specific environmental quality guidelines for Antarctica.

  19. Role of exposure mode in the bioavailability of triphenyl phosphate to aquatic organisms

    USGS Publications Warehouse

    Huckins, James N.; Fairchild, James F.; Boyle, Terence P.

    1991-01-01

    A laboratory study was conducted to investigate the role of the route of triphenyl phosphate (TPP) entry on its aquatic bioavailability and acute biological effects. Three TPP treatments were used for exposures of fish and invertebrates. These consisted of TPP dosed directly into water with and without clean sediment and TPP spiked onto sediment prior to aqueous exposures. Results of static acute toxicity tests (no sediment) were 0.78 mg/L (96-h LC50) for bluegill, 0.36 mg/L (48-h EC50) for midge, and 0.25 mg/L (96-h EC50) for scud. At 24 h, the sediment (1.1% organic carbon)/water partition coefficient (Kp) for TPP was 112. Use of this partition coefficient model to predict the sediment-mediated reduction of TPP concentration in water during toxicity tests resulted in a value that was only 10% less than the nominal value. However, the required nominal concentration of TPP to cause acute toxicity responses in test organisms was significantly higher than the predicted value by the model for both clay and soil-derived sediment. Direct spiking of TPP to soil minimized TPP bioavailability. Data from parallel experiments designed to track TPP residues in water through time suggest that sorption kinetics control residue bioavailability in the initial 24 h of exposure and may account for observed differences in LC50 and EC50 values from the sediment treatments.

  20. Effects of pH on the toxicities of cadmium, copper, and zinc to steelhead trout (salmo gairdneri) (journal version)

    SciTech Connect

    Cusimano, R.F.; Brakke, D.F.; Chapman, G.A.

    1986-01-01

    Increased metal concentrations have been associated with freshwater acidification. Continuous-flow acute toxicity tests were conducted in soft water to determine the effect of pH on the toxicity of cadmium, copper, and zinc to small (1-6 g) steelhead trout (Salmo gairdneri). LC50 values were calculated for 96- and 168-h exposure periods in waters of pH 4.7, 5.7, and 7.0. Test fish were significantly more tolerant of the metals at the lowest pH value than at higher pHs. The 96-h LC50 values at pH 4.7, 5.7, and 7.0 were 671, 97, and 66 micrograms/L for zinc, 66.0, 4.2 and 2.8 micrograms/L for copper, and 28.0, 0.7 and less than 0.5 micrograms/L for cadmium, respectively. The 168-h results were similar to the 96-h values. The results indicate that for the metals tested, toxicity is ameliorated in depressed pH waters over short exposure periods, such as may occur during snowmelt runoff. The possibility of hydrogen-ion interference with metal uptake is postulated.

  1. Acute toxicity of ammonia and nitrite to shortnose sturgeon fingerlings

    USGS Publications Warehouse

    Fontenot, Q.C.; Isely, J.J.; Tomasso, J.R.

    1998-01-01

    The 96-h median-lethal concentration (96-h LC50) of total ammonia nitrogen (ammonia-N) to fingerling shortnose sturgeon Acipenser brevirostrum was 149.8 ?? 55.20 mg/L (mean ?? SD, 17.9 ?? 0.62??C, pH = 6.8-7.3). Calculated 96-h LC50 for un-ionized ammonia-N was 0.58 ?? 0.213 mg/L. The 96-h LC50 of nitrite nitrogen to shortnose sturgeon fingerlings was 11.3 ?? 8.17 mg/L (17.9 ?? 0.31??C, <1.0 mg chloride/L, <1.0 mg magnesium/L, 1.8 mg calcium/L, 7.7 mg sodium/L).

  2. Acute effects of chlorinated resin acid exposure on juvenile rainbow trout, Oncorhynchus mykiss

    SciTech Connect

    Kennedy, C.J.; Sweeting, R.M.; Farrell, A.P.; McKeown, B.A.; Johansen, J.A.

    1995-06-01

    The effects of an acute exposure to either 14-monochlorodehydroabietic acid (MCDHAA) or 12,14-dichlorodehydroabietic acid (DCDHAA) were examined in juvenile rainbow trout, Oncorhynchus mykiss. The experimentally determined 96-h LC50 values (and their 95% confidence limits) were 1.03 (0.72, 1.48) and 0.91 (0.70, 1.21) mg/L, for MCDHAA and DCDHAA, respectively. To measure effects on several biochemical parameters, swimming performance, and disease resistance, juvenile trout were exposed for 24 h to sublethal concentrations of one or the other resin acid in an intermittent-flow respirometer. Hematocrit, plasma lactate, and liver protein were significantly affected by exposure to the highest dose (80% of the 96-h LC50 value) of either of the resin acids. Plasma cortisol levels were 14- and 3-fold higher than were controls. Resistance to infection by Aeromonas salmonicida was significantly reduced; the cumulative percent mortalities due to furunculosis in fish exposed to MCDHAA or DCDHAA reached 20 and 26%, respectively. Swimming performance, measured as critical swimming speed (mean values 6.32 {+-} 0.20 and 5.93 {+-} 0.15 body lengths per second for MCDHAA and DCDHAA, respectively), was not significantly affected by resin acid exposure.

  3. The effect of abiotic factors on the toxicity of cypermethrin against the snail Lymnaea acuminata in the control of fascioliasis.

    PubMed

    Singh, V; Singh, D K

    2009-03-01

    Every month during the year 2006-2007, the 24, 48, 72 and 96 h LC50 values of a molluscicide, cypermethrin, were determined for a snail Lymnaea acuminata, with concomitant estimation of levels of temperature, pH, dissolved oxygen and carbon dioxide and electrical conductivity, both in control and test water. On the basis of a 24 h toxicity assay, it was noted that LC50 values of 10.39, 10.90 and 11.19 mg l- 1 during the months of May, June and July, respectively, were most effective in killing the snails, while the molluscicide was least effective in the month of January, when its 24 h LC50 was 65.84 mg l- 1.There was a significant positive correlation between LC50 of cypermethrin and levels of dissolved O2/pH of water in corresponding months. On the contrary, a negative correlation was observed between LC50 and dissolved CO2/temperature of test water in the same months. In order to ascertain that such a relationship between toxicity and abiotic factors is not coincidental, the nervous tissue of the snail was assayed for the activity of acetylcholinesterase (AChE), acid phosphatase (ACP) and alkaline phosphatase (ALP) to sublethal concentrations (40% and 80%) of 24 h LC50 during each of the 12 months of the same year. The findings confirmed that abiotic factors indeed influence toxicity of cypermethrin in the snail. A significant positive rank correlation between AChE, ACP and ALP activity did exist following exposure to the corresponding sublethal concentrations. Moreover, there was a maximum inhibition of 61.29 and 76.16% of AChE and ACP, respectively, in snails exposed to 80% of the 24 h LC50 in the month of May. A similar treatment caused a maximum inhibition of 70.53% of ALP activity in the month of June. This work shows conclusively that the best time to control the snail population with cypermethrin is during the months of May and June.

  4. Influence of flow-through and renewal exposures on the toxicity of copper to rainbow trout

    USGS Publications Warehouse

    Welsh, P.G.; Lipton, J.; Mebane, C.A.; Marr, J.C.A.

    2008-01-01

    We examined changes in water chemistry and copper (Cu) toxicity in three paired renewal and flow-through acute bioassays with rainbow trout (Oncorhynchus mykiss). Test exposure methodology influenced both exposure water chemistry and measured Cu toxicity. Ammonia and organic carbon concentrations were higher and the fraction of dissolved Cu lower in renewal tests than in paired flow-through tests. Cu toxicity was also lower in renewal tests; 96 h dissolved Cu LC50 values were 7-60% higher than LC50s from matching flow-through tests. LC50 values in both types of tests were related to dissolved organic carbon (DOC) concentrations in exposure tanks. Increases in organic carbon concentrations in renewal tests were associated with reduced Cu toxicity, likely as a result of the lower bioavailability of Cu-organic carbon complexes. The biotic ligand model of acute Cu toxicity tended to underpredict toxicity in the presence of DOC. Model fits between predicted and observed toxicity were improved by assuming that only 50% of the measured DOC was reactive, and that this reactive fraction was present as fulvic acid. ?? 2007 Elsevier Inc. All rights reserved.

  5. Comparative toxicity of eight metals on freshwater fish.

    PubMed

    Shuhaimi-Othman, Mohammad; Yakub, Nadzifah; Ramle, Nur-Amalina; Abas, Ahmad

    2015-09-01

    Two freshwater fish, Rasbora sumatrana (Cyprinidae) and Poecilia reticulata (guppy; Poeciliidae), were exposed to a range of eight heavy metals (copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn)) at varied concentrations for 96 h in the laboratory. Mortality was assessed and median lethal concentrations (LC50) were calculated. It was observed that the LC50 values increased with a decrease in mean exposure times, for all metals and for both fish types. The 96-h LC50 values for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.006, 0.10, 0.46, 0.63, 0.83, 1.71, 1.53, and 5.71 mg/L for R. sumatrana and 0.038, 0.17, 1.06, 1.99, 15.62, 1.46, 6.76, and 23.91 mg/L for P. reticulata, respectively. The metal toxicity trend for R. sumatrana and P. reticulata from most to least toxic was Cu > Cd > Zn > Pb > Ni > Al > Fe > Mn and Cu > Cd > Zn > Fe > Pb > Al > Ni > Mn, respectively. Results indicated that Cu was the most toxic metal on both fish, and R. sumatrana was more sensitive than P. reticulata to all the eight metals.

  6. Effects of Endosulfan on Predator-Prey Interactions Between Catfish and Schistosoma Host Snails.

    PubMed

    Monde, Concillia; Syampungani, Stephen; Van den Brink, Paul J

    2016-08-01

    The effect of the pesticide endosulfan on predator-prey interactions between catfish and Schistosoma host snails was assessed in static tank experiments. Hybrid catfish (Clarias gariepinus × C. ngamensis) and Bulinus globosus were subjected to various endosulfan concentrations including an untreated control. The 48- and 96-h LC50 values for catfish were 1.0 and <0.5 µg/L, respectively, whereas the 48- and 96-h LC50 values for snails were 1137 and 810 µg/L. To assess sublethal effects on the feeding of the catfish on B. globosus, endosulfan concentrations between 0.03 and 1.0 µg/L were used. Predation was significantly greater (p < 0.001) in control tanks than in all other treatments. There was progressively decreasing predation with increasing toxicant concentration. Biological control of Schistosoma host snails using fish may be affected in endosulfan-polluted aquatic systems of Southern Africa because it has been found present at concentrations that are indicated to cause lethal effects on the evaluated hybrid catfish and to inhibit the predation of snails by this hybrid catfish. PMID:27033099

  7. Effect of subacute exposure to silver nanoparticle on some hematological and plasma biochemical indices in silver carp (Hypophthalmichthys molitrix).

    PubMed

    Shaluei, F; Hedayati, A; Jahanbakhshi, A; Kolangi, H; Fotovat, M

    2013-12-01

    The use of silver nanoparticles (Ag-NPs) is rapidly increasing, but there are limited data on their effects on the aquatic environment. The present study aimed to determine the acute toxicity and evaluate the effect of subacute concentrations of Ag-NPs (Nanocid®: average particle size of 61 nm) on hematological and plasma biochemical indices of silver carp, Hypophthalmichthys molitrix, after 3, 7 and 14 days. The 24-, 48-, 72- and 96-h median lethal concentration (LC50) values of Nanocid for silver carp were estimated at 0.810, 0.648, 0.383 and 0.202 mg/L, respectively; 20% and 10% of the 96-h LC50 values (0.04 and 0.02 mg/L) were selected for subacute study. Red blood cell (RBC) count, hemoglobin (Hb) count and hematocrit (Hct) level were significantly reduced at both concentrations tested (p < 0.05). White blood cell (WBC), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), cortisol and glucose levels in Nanocid-treated groups were significantly higher than the controlled group at experimental periods (p < 0.05). In conclusion, Ag-NPs intoxication resulted in erythrocyte reduction, hematological disturbances, leucocytosis and stress response in silver carp and offered a simple tool to evaluate toxicity-derived alterations. PMID:23632006

  8. Molluscicidal activity of Piper cubeba Linn., Piper longum Linn. and Tribulus terrestris Linn. and their combinations against snail Indoplanorbis exustus Desh.

    PubMed

    Pandey, Jitendra K; Singh, D K

    2009-08-01

    The toxic effect of dried berries powder of P. cubeba, dried fruit powder of P. longum and T. terrestris singly as well as in combination [binary (1:1) and tertiary (1:1:1)] were studied against snail L. exustus. Toxicity of these plant products were time and concentration dependent. Ethanol extracts of these plants were more effective than that of other organic solvents. 96 h LC50 value of column purified fraction of T. terrestris against I. exustus was 9.57 mg/l, where as 96 h LC50 values of column purified fractions of P. longum and P. cubeba were 11.57 mg/l and 10.93 mg/l, respectively. Binary (1:1) combination of P. cubeba (PC) + P. longum (PL) (41.78 mg/l) was more effective than P. cubeba (PC) + T. terrestris (TT) (42.17 mg/l) and P. longum (PL) + T. terrestris (TT) (55.84 mg/l) respectively; while tertiary (1:1:1) combinations of P. cubeba (PC) + T. terrestris (TT) + T. foenum-graecum (TF) (10.67 mg/l) was more effective than rest of the combinations. These plants can be used as potent source of molluscicides against the snail I. exustus.

  9. Short-term toxicity of ammonia, sodium hydroxide and a commercial biocide to golden mussel Limnoperna fortunei (Dunker, 1857).

    PubMed

    Montresor, Lângia C; Miranda-Filho, Kleber C; Paglia, Adriano; Luz, Dalva M R; Araújo, Juliano M; dos S Silva, Márcio José; Gerhard, Luciana; Martinez, Carlos B; Vidigal, Teofânia H D A

    2013-06-01

    Macrofouling bivalves are considered an ecological and technological problem worldwide. Control measures have been researched with Limnoperna fortunei, but without success. The aim of the manuscript is to test some alternatives to regulate this harmful invasive mollusk. Mortality and behavioral response (shell gaping) of Limnoperna fortunei exposed to three chemical compounds were evaluated. Values for LC50 96h were: 0.25 (0.24-0.27)mg/L NH3-N, 11.10 (7.45-16.55) mg/L MXD-100 and 88.51 (74.61-105.01)mg/L NaOH. Reduced gaping was observed beginning at concentrations of 0.31mg/L (NH3-N), 100mg/L (MXD-100) and 160mg/L (NaOH) and increased above these values. The percentage of individuals gaping after two hours at LC50 96h differed significantly (χ(2)=79.9; DF=3; p<0.001) in MXD-100 (50%), NaOH (0%), NH3-N (96.7%) and the controls (93.3%). This study contributes to the understanding of the relationship between toxicity and behavioral effects of some toxicants in L. fortunei.

  10. Acute and subchronic toxicity of arsenite and zinc to tadpoles of Rhinella arenarum both alone and in combination.

    PubMed

    Brodeur, Julie Céline; Asorey, Cynthia Melina; Sztrum, Abelardo; Herkovits, Jorge

    2009-01-01

    The current study evaluated acute and subchronic toxicity of arsenite (As(3+)) and zinc (Zn(2+)) to stage 25 tadpoles of Rhinella arenarum in both single and joint laboratory exposures. LC50 values obtained for As(3+) were elevated and remained within the range of 46 to 50 mg/L of As(3+) between 4 and 17 d of exposure. Growth of tadpoles was completely inhibited with 30 mg/L of As(3+), demonstrating the presence of ecologically relevant sublethal effects at concentrations lower than those resulting in lethality. With respect to Zn(2+), a 96-h LC50 value of 2.49 mg/L was calculated in soft water. Contrary to results obtained for As(3+), LC50 values of Zn(2+) gradually decreased with increasing exposure duration, from 2.49 mg/L at 96 h to 1.30 mg/L after 21 d. In joint exposures to both metals, the type of interaction observed between As(3+) and Zn(2+) was concentration dependent. Lethal effects of As(3+) were mitigated, unaffected, or potentiated by 0.01, 0.1, and 1-2 mg/L of Zn(2+), respectively. However, although 0.01 mg/L of Zn(2+) significantly reduced lethality of As(3+)-exposed tadpoles, the same concentration of Zn(2+) did not help to reverse the stunt growth of these animals. Further studies need to examine which are the lowest concentrations As(3+) required to reduce growth and whether Zn(2+) serves to antagonize growth effects in this range of concentrations. PMID:19557616

  11. Combined effects of cadmium and composted manure to aquatic organisms.

    PubMed

    Ghosal, Tapan Kumar; Kaviraj, Anilava

    2002-02-01

    To evaluate the interactive toxicity of cadmium (Cd) and composted manure to aquatic organisms 96 h static bioassays were conducted in the laboratory with fry of common carp (Cyprinus carpio), copepod (Diaptomusforbesi) and oligochaete worm (Branchiura sowerbyi). Five concentrations of composted manure (0, 0.25, 0.5, 1.0 and 6.7 g/l) were prepared from the aquatic weed, Pistia stratiotes and each of them was combined with several concentrations of Cd to determine 96 h LC-50 values of Cd for the test organisms. Addition of composted manure, irrespective of concentration, significantly reduced the LC-50 value of Cd to the copepod and common carp fry while it increased the LC-50 value of Cd to the worm. Increased susceptibility of the worm to combined treatment of composted manure and small concentrations of Cd could be revealed only from the dose mortality curve. Results of acute toxicity bioassays were different from the results of bioassays conducted with small concentrations of Cd. Worms, exposed to 2.5 mg/l Cd, accumulated more Cd than did the carp fry and copepod. Accumulation of Cd by worms was increased by the addition of 6.7 g/l composted manure while it decreased in the carp fry and copepod. Food consumption rate of common carp fingerling was significantly reduced relative to the control by exposure to 2.5 mg/l Cd. No change in feeding rate was observed when Cd was combined with composted manure (6.7 g/l). PMID:11999773

  12. Comparison of the sensitivity of Danio rerio and Poecilia reticulata to silver nitrate in short-term tests.

    PubMed

    Doleželová, Petra; Mácová, Stanislava; Pištěková, Vladimíra; Svobodová, Zdeňka; Bedáňová, Iveta; Voslářová, Eva

    2008-09-01

    The aim of this study is to assess the acute toxicity of silver nitrate in adult zebra fish and adult guppies and to compare the sensitivity of these species to this compound. Silver is a naturally occurring element in our environment and it combines with other elements such as sulfide, chloride, and nitrate. Silver, in the form of silver nitrate, is one of the most toxic metals affecting freshwater fish. Industry, particularly photographical and electrotechnical, is the major contributor of silver that is released into the environment. Tests of acute toxicity were performed on the most common species of aquarium fish, Danio rerio and Poecilia reticulata. Both zebra fish and guppies were exposed to progressive concentrations of silver nitrate; a semi-static method according to OECD 203 was used. In each test series, 6 tests of acute toxicity were conducted, with 10 fish used for each separate concentration and for the control group. The results (number of fish deaths in the individual test concentrations) were subjected to probit analysis (EKO-TOX 5.1 software) to determine the 96hLC(50) AgNO(3) values. The 96hLC(50) AgNO(3) value for the zebra fish was (mean±SEM) 15±0.52 µg/l and for the guppies was (mean±SEM) 17.14±5.43 µg/l. We didn't find any statistically significant difference between the sensitivity of zebra fish and guppies. The results reported in this study are in agreement with LC(50) values published in peer-reviewed literature, and conclude that AgNO(3) is one of the most toxic compounds known to fishery. PMID:21218114

  13. Effects of developmental stage, salts, and food presence on aquatic toxicological endpoints using Caenorhabditis elegans

    SciTech Connect

    Donkin, S.G.; Williams, P.L.

    1995-12-31

    The objective of this study was to standardize the testing protocol for aquatic toxicity tests with the nematode Caenorhabditis elegans. Several variables which may be important in determining the test outcome were investigated in a randomized block design. Concentration-response data were obtained on nematodes of various developmental stages exposed to four metals (Cd, Pb, Cu, and Hg) and a water-soluble organic toxicant, sodium Pentachlorophenate (PCP), under conditions of varied solvent medium (with or without salts and with or without a bacterial food source). The endpoints measured were 24 and 96-h mortality, as well as development of larval stages to adulthood and evidence of reproduction. The results suggest that nematodes of various ages respond similarly to a given toxicant for all endpoints measured, although adults cultured from eggs appeared more sensitive than adults cultured from dauer larvae. The most important environmental variable in determining toxicity was the medium in which the tests were conducted. The presence of potassium and sodium salts in the medium significantly (p<0.05) reduced the toxicity of many test samples. The presence of bacteria had little effect on 24-h tests with salts, but was important in 96-h survival and development. Based on sensitivity and ease of handling, adults cultured from eggs are recommended in both 24-h and 96-h mortality (LC50 value) tests, as well as 96-h reproduction tests.

  14. Effects of copper, nickel, and zinc on three species of Oregon freshwater snails

    SciTech Connect

    Nebeker, A.V.; Stinchfield, A.; Savonen, C.; Chapman, G.A.

    1986-01-01

    Three snail species collected from western Oregon were exposed to metals - Juga plicifera and Lithoglyphus virens, which inhabit cool coastal streams, and Physa gyrina, which is found in Willamette Valley ponds. J. plicifera were exposed in flow-through laboratory tests to copper and nickel, L. virens were exposed to copper, and P. gyrina were exposed to nickel and zinc. J. plicifera has a 96-h LC50 (50% of the test group died) of 0.015 mg/L for copper and a no observed effect level (NOEL, mortality not significantly different from that in control groups) of 0.006 mg/L (30-d survival). J. plicifera had a 96-h LC50 for nickel of 0.237 mg/L and a NOEL of 0.124 mg/L. L. virens had a 96-h LC50 for copper of 0.008 mg/L and a NOEL of less than 0.008 mg/L. P. gyrina had a 96-h LC50 for nickel of 0.239 mg/L, a 96-h LC50 for zinc of 1.274 mg/L and a NOEL for zinc of 0.570 mg/L.

  15. Factors affecting toxicity test endpoints in sensitive life stages of native Gulf of Mexico species.

    PubMed

    Echols, B S; Smith, A J; Rand, G M; Seda, B C

    2015-05-01

    Indigenous species are less commonly used in laboratory aquatic toxicity tests compared with standard test species due to (1) limited availability lack of requisite information necessary for their acclimation and maintenance under laboratory conditions and (2) lack of information on their sensitivity and the reproducibility of toxicity test results. As part of the Natural Resource Damage Assessment aquatic toxicity program in response to the Deepwater Horizon Oil incident (2010), sensitive life stages of native Gulf of Mexico species were evaluated in laboratory toxicity tests to determine the potential effects of the spill. Fish (n = 5) and invertebrates (n = 2) selected for this program include the following: the Florida pompano (Trachinotus carolinus), red drum (Sciaenops ocellatus), spotted sea trout (Cynoscion nebulosus), cobia (Rachycentron canadum), red porgy (Pagrus pagrus), blue crab (Callinectes sapidus), and the common moon jellyfish (Aurelia aurita). Initially in the program, to establish part of the background information, acute tests with reference toxicants (CdCl2, KCl, CuSO4) were performed with each species to establish data on intraspecies variability and test precision as well as identify other factors that may affect toxicity results. Median lethal concentration (LC50) values were calculated for each acute toxicity test with average LC50 values ranging from 248 to 862 mg/L for fish exposures to potassium chloride. Variability between test results was determined for each species by calculating the coefficient of variation (%CV) based on LC50 values. CVs ranged from 11.2 % for pompano (96-h LC50 value) to 74.8 % for red porgy 24-h tests. Cadmium chloride acute toxicity tests with the jellyfish A. aurita had the lowest overall CV of 3.6 %. By understanding acute toxicity to these native organisms from a compound with known toxicity ranges and the variability in test results, acute tests with nonstandard species can be better interpreted and used

  16. Factors affecting toxicity test endpoints in sensitive life stages of native Gulf of Mexico species.

    PubMed

    Echols, B S; Smith, A J; Rand, G M; Seda, B C

    2015-05-01

    Indigenous species are less commonly used in laboratory aquatic toxicity tests compared with standard test species due to (1) limited availability lack of requisite information necessary for their acclimation and maintenance under laboratory conditions and (2) lack of information on their sensitivity and the reproducibility of toxicity test results. As part of the Natural Resource Damage Assessment aquatic toxicity program in response to the Deepwater Horizon Oil incident (2010), sensitive life stages of native Gulf of Mexico species were evaluated in laboratory toxicity tests to determine the potential effects of the spill. Fish (n = 5) and invertebrates (n = 2) selected for this program include the following: the Florida pompano (Trachinotus carolinus), red drum (Sciaenops ocellatus), spotted sea trout (Cynoscion nebulosus), cobia (Rachycentron canadum), red porgy (Pagrus pagrus), blue crab (Callinectes sapidus), and the common moon jellyfish (Aurelia aurita). Initially in the program, to establish part of the background information, acute tests with reference toxicants (CdCl2, KCl, CuSO4) were performed with each species to establish data on intraspecies variability and test precision as well as identify other factors that may affect toxicity results. Median lethal concentration (LC50) values were calculated for each acute toxicity test with average LC50 values ranging from 248 to 862 mg/L for fish exposures to potassium chloride. Variability between test results was determined for each species by calculating the coefficient of variation (%CV) based on LC50 values. CVs ranged from 11.2 % for pompano (96-h LC50 value) to 74.8 % for red porgy 24-h tests. Cadmium chloride acute toxicity tests with the jellyfish A. aurita had the lowest overall CV of 3.6 %. By understanding acute toxicity to these native organisms from a compound with known toxicity ranges and the variability in test results, acute tests with nonstandard species can be better interpreted and used

  17. Sensitivity of the deep-sea amphipod Eurythenes gryllus to chemically dispersed oil.

    PubMed

    Olsen, Gro Harlaug; Coquillé, Nathalie; Le Floch, Stephane; Geraudie, Perrine; Dussauze, Matthieu; Lemaire, Philippe; Camus, Lionel

    2016-04-01

    In the context of an oil spill accident and the following oil spill response, much attention is given to the use of dispersants. Dispersants are used to disperse an oil slick from the sea surface into the water column generating a cloud of dispersed oil droplets. The main consequence is an increasing of the sea water-oil interface which induces an increase of the oil biodegradation. Hence, the use of dispersants can be effective in preventing oiling of sensitive coastal environments. Also, in case of an oil blowout from the seabed, subsea injection of dispersants may offer some benefits compared to containment and recovery of the oil or in situ burning operation at the sea surface. However, biological effects of dispersed oil are poorly understood for deep-sea species. Most effects studies on dispersed oil and also other oil-related compounds have been focusing on more shallow water species. This is the first approach to assess the sensitivity of a macro-benthic deep-sea organism to dispersed oil. This paper describes a toxicity test which was performed on the macro-benthic deep-sea amphipod (Eurythenes gryllus) to determine the concentration causing lethality to 50% of test individuals (LC50) after an exposure to dispersed Brut Arabian Light (BAL) oil. The LC50 (24 h) was 101 and 24 mg L(-1) after 72 h and 12 mg L(-1) at 96 h. Based on EPA scale of toxicity categories to aquatic organisms, an LC50 (96 h) of 12 mg L(-1) indicates that the dispersed oil was slightly to moderately toxic to E. gryllus. As an attempt to compare our results to others, a literature study was performed. Due to limited amount of data available for dispersed oil and amphipods, information on other crustacean species and other oil-related compounds was also collected. Only one study on dispersed oil and amphipods was found, the LC50 value in this study was similar to the LC50 value of E. gryllus in our study. Since toxicity data are important input to risk assessment and net environmental

  18. Sensitivity of the deep-sea amphipod Eurythenes gryllus to chemically dispersed oil.

    PubMed

    Olsen, Gro Harlaug; Coquillé, Nathalie; Le Floch, Stephane; Geraudie, Perrine; Dussauze, Matthieu; Lemaire, Philippe; Camus, Lionel

    2016-04-01

    In the context of an oil spill accident and the following oil spill response, much attention is given to the use of dispersants. Dispersants are used to disperse an oil slick from the sea surface into the water column generating a cloud of dispersed oil droplets. The main consequence is an increasing of the sea water-oil interface which induces an increase of the oil biodegradation. Hence, the use of dispersants can be effective in preventing oiling of sensitive coastal environments. Also, in case of an oil blowout from the seabed, subsea injection of dispersants may offer some benefits compared to containment and recovery of the oil or in situ burning operation at the sea surface. However, biological effects of dispersed oil are poorly understood for deep-sea species. Most effects studies on dispersed oil and also other oil-related compounds have been focusing on more shallow water species. This is the first approach to assess the sensitivity of a macro-benthic deep-sea organism to dispersed oil. This paper describes a toxicity test which was performed on the macro-benthic deep-sea amphipod (Eurythenes gryllus) to determine the concentration causing lethality to 50% of test individuals (LC50) after an exposure to dispersed Brut Arabian Light (BAL) oil. The LC50 (24 h) was 101 and 24 mg L(-1) after 72 h and 12 mg L(-1) at 96 h. Based on EPA scale of toxicity categories to aquatic organisms, an LC50 (96 h) of 12 mg L(-1) indicates that the dispersed oil was slightly to moderately toxic to E. gryllus. As an attempt to compare our results to others, a literature study was performed. Due to limited amount of data available for dispersed oil and amphipods, information on other crustacean species and other oil-related compounds was also collected. Only one study on dispersed oil and amphipods was found, the LC50 value in this study was similar to the LC50 value of E. gryllus in our study. Since toxicity data are important input to risk assessment and net environmental

  19. Acute toxicity, uptake and accumulation kinetics of nickel in an invasive copepod species: Pseudodiaptomus marinus.

    PubMed

    Tlili, Sofiène; Ovaert, Julien; Souissi, Anissa; Ouddane, Baghdad; Souissi, Sami

    2016-02-01

    Pseudodiaptomus marinus is a marine calanoid copepod originating of the Indo-Pacific region, who has successfully colonized new areas and it was recently observed in the European side of the Mediterranean Sea as well as in the North Sea. Actually, many questions were posed about the invasive capacity of this copepod in several non-native ecosystems. In this context, the main aim of this study was to investigate the tolerance and the bioaccumulation of metallic stress in the invasive copepod P. marinus successfully maintained in mass culture at laboratory conditions since 2 years. In order to study the metallic tolerance levels of P. marinus, an emergent trace metal, the nickel, was chosen. First, lethal concentrations determination experiments were done for 24, 48, 72 and 96 h in order to calculated LC50% but also to select a relevant ecological value for the suite of experiments. Then, three types of experiments, using a single concentration of nickel (correspond the 1/3 of 96 h-LC50%) was carried in order to study the toxico-kinetics of nickel in P. marinus. Concerning lethal concentrations, we observed that P. marinus was in the same range of sensitivity compared to other calanoid copepods exposed to nickel in the same standardized experimental conditions. Results showed that the uptake of nickel in P. marinus depends from the pathways of entrance (water of food), but also that Isochrysis galbana, used as a food source, has an important bioaccumulation capacity and a rapid uptake of nickel.

  20. Acute toxicity of fire-retardant and foam-suppressant chemicals to early life stages of chinook salmon (Oncorhynchus tshawytscha)

    USGS Publications Warehouse

    Buhl, Kevin J.; Hamilton, Steven J.

    1998-01-01

    Laboratorys studies were conducted to determine the acute toxicity of three fire retardants (Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F), and two fire-suppressant foams (Phos-Chek WD-881 and Ansul Silv-Ex) to early life stages of chinook salmon, Oncorhynchus tshawytscha, in hard and soft water. Regardless of water type, swim-up fry and juveniles (60 and 90 d posthatch) exhibited similar sensitivities to each chemical and these life stages were more sensitive than eyed eggs. Foam suppressants were more toxic to each life stage than the fire retardants in both water types. The descending rank order of toxicity for these chemicals tested with swim-up fry and juveniles (range of 96-h median lethal concentrations [LC50s]) was Phos-Chek WD-881 (7–13 mg/L) > Ansul Silv-Ex (11–22 mg/L) > Phos-Chek D75-F (218–305 mg/L) > Fire-Trol GTS-R (218–412 mg/L) > Fire-Trol LCG-R (685–1,195 mg/L). Water type had a minor effect on the toxicity of these chemicals. Comparison of acute toxicity values with recommended application concentrations indicates that accidental inputs of these chemicals into stream environments would require substantial dilution (237- to 1,429-fold) to reach concentrations equivalent to their 96-h LC50s.

  1. Acute toxicity of organochlorine insecticide endosulfan to the giant freshwater prawn Macrobrochium rosenbergii

    NASA Astrophysics Data System (ADS)

    Dai, Xilin; Xiong, Zhaodi; Xie, Jian; Ding, Fujiang

    2014-01-01

    Endosulfan, an organochlorine pesticide, is highly toxic and effective at controlling pests in agriculture, horticulture, and public health programs. In this study, static bioassays were used to evaluate the toxicity of endosulfan to freshwater prawns ( Macrobrachium rosenbergii) of various lengths (1.5±0.03, 4±0.08, and 7±0.06 cm). Additionally, the activities of peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase, acetylcholinesterase (AChE), and Na+/K+-ATPase were analyzed to reflect the effects of endosulfan exposure. The 96 h LC50 of endosulfan for prawns 1.5, 4, and 7 cm long were 1.86, 4.53, and 6.09 μg/L, respectively, improved tolerance to endosulfan with growth. The POD activities of test organisms exposed to low concentrations of endosulfan were inhibited, indicating the presence of oxygen damaged tissue. Moreover, a notable decrease in AChE activity was observed due to overstimulation of neurotransmission, which might result in abnormal behavior. The effect caused by endosulfan on phosphatase production in the hepatopancreas of prawns 1.5, 4, and 7 cm long was different because the ability of nonspecific immune regulation increased with growth. The 96 h LC50 values obtained in this study could be used in the formulation of water-quality criteria in China. Moreover, the changes in enzymes activities of M. rosenbergii under stress of endosulfan could be applied in the establishment of early warning indicators for bio-safety.

  2. Proteomic and histopathological response in the gills of Poecilia reticulata exposed to glyphosate-based herbicide.

    PubMed

    Rocha, Thiago Lopes; Santos, Ana Paula Rezende Dos; Yamada, Áureo Tatsumi; Soares, Célia Maria de Almeida; Borges, Clayton Luiz; Bailão, Alexandre Melo; Sabóia-Morais, Simone Maria Teixeira

    2015-07-01

    Glyphosate-based herbicides (GBH) are one of the most used herbicide nowadays, whilst there is growing concern over their impact on aquatic environment. Since data about the early proteomic response and toxic mechanisms of GBH in fish is very limited, the aim of this study was to investigate the early toxicity of GBH in the gills of guppies Poecilia reticulata using a proteomic approach associated with histopathological index. Median lethal concentration (LC50,96 h) was determined and LC50,96h values of guppies exposed to GBH were 3.6 ± 0.4 mg GLIL(-1). Using two-dimensional gel electrophoresis associated with mass spectrometry, 14 proteins regulated by GBH were identified, which are involved in different cell processes, as energy metabolism, regulation and maintenance of cytoskeleton, nucleic acid metabolism and stress response. Guppies exposed to GBH at 1.82 mg GLIL(-1) showed time-dependent histopathological response in different epithelial and muscle cell types. The histopathological indexes indicate that GBH cause regressive, vascular and progressive disorders in the gills of guppies. This study helped to unravel the molecular and tissue mechanisms associated with GBH toxicity, which are potential biomarkers for biomonitoring water pollution by herbicides.

  3. Laboratory study on the ecological impact of sophorolipid used for harmful algae elimination

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoxia; Kim, Eunki; Sun, Song

    2010-11-01

    We studied the role of sophorolipid in inhibiting harmful algae bloom (HAB). Different sophorolipid concentrations were tested on marine microalgae, zooplankton, fish, and bivalve ( Mytilus edulis) in laboratory. The result shows that sophorolipid could inhibit the growth of algal species selectively. Among three algae species selected, Platymonas helgolandica var. tsingtaoensis was promoted with increasing sophorolipid concentration; Isochrysis galbana was inhibited seven days later in sophorolipid concentration below 40 mg/L; and Nitzschia closterium f. minutissima was inhibited obviously in only a high sophorolipid concentration over 20 mg/L. Therefore, sophorolipid in a low concentration at <20 mg/L could remove certain harmful algae species effectively without harming other non-harmful microalgae. For other animals, sophorolipid could inhibit the growth of ciliate Strombidium sp. by 50% at 20 mg/L sophorolipid concentration after 96 h. The concentration in 96-h LC50 for Calanus sinicus, Neomysis awatschensis, Lateolabrax japonicus, and Paralichthys olivaceus was 15, 150, 60, and 110 mg/L, respectively. The 24 h LC50 value for Artemia salina was 600 mg/L. The relative clearance rate of mussel Mytilus edulis decreased to 80%, 40%, and 20% of the control group after being exposed to 20, 50, and 100 mg/L sophorolipid for 24 h. Therefore, the toxicity for mitigation of harmful algae bloom at previously recommended concentration of 5-20 mg/L sophorolipid is low for most tested organisms in this reaserch.

  4. Evaluation of the toxicity and teratogenity of six commercial textile dyes using the frog embryo teratogenesis assay-Xenopus.

    PubMed

    Birhanli, Ayse; Ozmen, Murat

    2005-01-01

    Potential developmental toxicities of six different textile dyes were evaluated using the frog embryo teratogenesis assay-Xenopus (FETAX). Xenopus laevis embryos were exposed to astrazon red FBL, astrazon blue FGRL, remazol red RR, remazol turquoise blue G-A, cibacron red FN-3G, and cibacron blue FN-R from stage 8 to 11 for a 96-h exposure period in static renewal test conditions. A minimum of 17 concentration-response tests were performed with tested dyes, excluding a control group for each dye. Median lethal concentration (LC50), malformation (EC50), non observed adverse effect concentration (NOAEC), and lowest observed adverse effect concentration (LOAEC) were calculated. Also, teratogenic index (TI), minimum concentration to inhibit growth (MCIG), and MCIG/LC50 values were determined for each of the tested dyes. Characteristic abnormalities induced by a given test material were determined by the relationship between concentration and dye in the study. Results from these studies suggested that each tested dye is teratogenic for X. laevis embryos. The lowest LC50 was determined for astrazon red exposure corresponding to a value of 4.73 mg/L. The LC50 value was similar for this dye and astrazon blue; the highest TI was calculated for astrazon blue exposure. Tests with X. laevis indicated that each of the tested compounds possessed teratogenic potential with varying degrees of potency: astrazon blue FGRL > remazol turquoise blue G-A > astrazon red FBL > cibacron blue FN-R > cibacron red FN-3G > remazol red RR. Different types of malformations occurred in the embryos, depending on concentration and dye. From these results, we can suggest that astrazon blue is the most toxic compound, but that the others are also highly toxic and teratogenic substances for X. laevis embryos. Results of the study confirmed that the FETAX assay can be useful in an integrated biological hazard assesment for the preliminary screening of textile dye stuff.

  5. Chlorpyrifos-based insecticides induced genotoxic and cytotoxic effects in the ten spotted live-bearer fish, Cnesterodon decemmaculatus (Jenyns, 1842).

    PubMed

    Vera-Candioti, Josefina; Soloneski, Sonia; Larramendy, Marcelo L

    2014-12-01

    Mortality, genotoxicity, and cytotoxicity of the 48% chlorpyrifos (CPF)-based formulations Lorsban* 48E(®) and CPF Zamba(®) were evaluated on Cnesterodon decemmaculatus (Jenyns, 1842) (Pisces, Poeciliidae) under laboratory conditions. Induction of micronucleus (MN) and alterations in the erythrocyte/erythroblast frequencies were employed as end points for genotoxicity and cytotoxicity, respectively. For Lorsban* 48E(®) , mean values of 0.13 and 0.03 mg/L were determined for LC50 at 24 and 96 h, respectively, and these concentrations reached mean values of 0.40 and 0.21 mg/L for CPF Zamba(®) . Mortality values increased as a positive linear function of the CPF Zamba(®) concentrations, but not for Lorsban* 48E(®) concentrations. There was no significant relationship between mortality and exposure time within the 0-96 h period for both formulations. LC50 values indicated that the fish were seven fold more sensitive to Lorsban* 48E(®) than to CPF Zamba(®) . Lorsban* 48E(®) within the concentration range of 0.008-0.025 mg/L increased MN frequency at both 48 and 96 h of treatment. Similar results were also observed when fish were exposed to 0.052-0.155 mg/L of CPF Zamba(®) , regardless of the exposure time. Cellular cytotoxicity was found after Lorsban* 48E(®) and CPF Zamba(®) treatments for all concentrations and time exposures, estimated by a decrease in the frequency of mature erythrocytes and a concomitant enhanced frequency of erythroblasts in circulating blood. Furthermore, our results demonstrated that Lorsban* 48E(®) and CPF Zamba(®) should be considered as CPF-based commercial formulations with marked genotoxic and cytotoxic properties.

  6. Value Added?

    ERIC Educational Resources Information Center

    UCLA IDEA, 2012

    2012-01-01

    Value added measures (VAM) uses changes in student test scores to determine how much "value" an individual teacher has "added" to student growth during the school year. Some policymakers, school districts, and educational advocates have applauded VAM as a straightforward measure of teacher effectiveness: the better a teacher, the better students…

  7. Temperature-dependent toxicities of four common chemical pollutants to the marine medaka fish, copepod and rotifer.

    PubMed

    Li, Adela J; Leung, Priscilla T Y; Bao, Vivien W W; Yi, Andy X L; Leung, Kenneth M Y

    2014-10-01

    We hypothesize that chemical toxicity to marine ectotherms is the lowest at an optimum temperature (OT) and it exacerbates with increasing or decreasing temperature from the OT. This study aimed to verify this hypothetical temperature-dependent chemical toxicity (TDCT) model through laboratory experiments. Acute toxicity over a range of temperatures was tested on four commonly used chemicals to three marine ectotherms. Our results confirmed that toxicities, in terms of 96-h LC50 (median lethal concentration; for the marine medaka fish Oryzias melastigma and the copepod Tigriopus japonicus) and 24-h LC50 (for the rotifer Brachionus koreanus), were highly temperature-dependent, and varied between test species and between study chemicals. The LC50 value of the fish peaked at 20 °C for copper (II) sulphate pentahydrate and triphenyltin chloride, and at 25 °C for dichlorophenyltrichloroethane and copper pyrithione, and decreased with temperature increase or decrease from the peak (i.e., OT). However, LC50 values of the copepod and the rotifer generally showed a negative relationship with temperature across all test chemicals. Both copepod and rotifer entered dormancy at the lowest temperature of 4 °C. Such metabolic depression responses in these zooplanktons could reduce their uptake of the chemical and hence minimize the chemical toxicity at low temperatures. Our TDCT model is supported by the fish data only, whereas a simple linear model fits better to the zooplankton data. Such species-specific TDCT patterns may be jointly ascribed to temperature-mediated changes in (1) the physiological response and susceptibility of the marine ectotherms to the chemical, (2) speciation and bioavailability of the chemical, and (3) toxicokinetics of the chemical in the organisms.

  8. Temperature-dependent toxicities of four common chemical pollutants to the marine medaka fish, copepod and rotifer.

    PubMed

    Li, Adela J; Leung, Priscilla T Y; Bao, Vivien W W; Yi, Andy X L; Leung, Kenneth M Y

    2014-10-01

    We hypothesize that chemical toxicity to marine ectotherms is the lowest at an optimum temperature (OT) and it exacerbates with increasing or decreasing temperature from the OT. This study aimed to verify this hypothetical temperature-dependent chemical toxicity (TDCT) model through laboratory experiments. Acute toxicity over a range of temperatures was tested on four commonly used chemicals to three marine ectotherms. Our results confirmed that toxicities, in terms of 96-h LC50 (median lethal concentration; for the marine medaka fish Oryzias melastigma and the copepod Tigriopus japonicus) and 24-h LC50 (for the rotifer Brachionus koreanus), were highly temperature-dependent, and varied between test species and between study chemicals. The LC50 value of the fish peaked at 20 °C for copper (II) sulphate pentahydrate and triphenyltin chloride, and at 25 °C for dichlorophenyltrichloroethane and copper pyrithione, and decreased with temperature increase or decrease from the peak (i.e., OT). However, LC50 values of the copepod and the rotifer generally showed a negative relationship with temperature across all test chemicals. Both copepod and rotifer entered dormancy at the lowest temperature of 4 °C. Such metabolic depression responses in these zooplanktons could reduce their uptake of the chemical and hence minimize the chemical toxicity at low temperatures. Our TDCT model is supported by the fish data only, whereas a simple linear model fits better to the zooplankton data. Such species-specific TDCT patterns may be jointly ascribed to temperature-mediated changes in (1) the physiological response and susceptibility of the marine ectotherms to the chemical, (2) speciation and bioavailability of the chemical, and (3) toxicokinetics of the chemical in the organisms. PMID:25098775

  9. Carbon nanotubes enhanced the lead toxicity on the freshwater fish

    NASA Astrophysics Data System (ADS)

    Martinez, D. S. T.; Alves, O. L.; Barbieri, E.

    2013-04-01

    Carbon nanotubes are promising nanostructures for many applications in materials industry and biotechnology. However, it is mandatory to evaluate their toxicity and environmental implications. We evaluated nitric acid treated multiwalled carbon nanotubes (HNO3-MWCNT) toxicity in Nile tilapia (Oreochromis niloticus) and also the lead (Pb) toxicity modulation after the nanotube interaction. Industrial grade multiwalled carbon nanotubes [Ctube 100, CNT Co. Ltd] were treated with 9M HNO3 for 12h at 150°C to generate oxygenated groups on the nanotube surface, to improve water dispersion and heavy metal interaction. The HNO3-treated multiwalled carbon nanotubes were physico-chemically characterized by several techniques [e.g. TEM, FE-SEM, TGA, ζ-potential and Raman spectroscopy]. HNO3-MWCNT did not show toxicity on Nile tilapia when the concentration ranged from 0.1 to 3.0 mg/L, and the maximum exposure time was 96h. After 24, 48, 72 and 96h the LC50 values of Pb were 1.65, 1.32, 1.10 and 0.99 mg/L, respectively. To evaluate the Pb-nanotube interaction influence on the ecotoxicity, we submitted the Nile tilapia to different concentrations of Pb mixed with a non-toxic concentration of HNO3-MWCNT (1.0 mg/L). After 24, 48, 72, 96 h the LC50 values of Pb plus nanotubes were: 0.32, 0.25, 0.20, 0.18 mg/L, respectively. These values showed a synergistic effect after Pb-nanotube interaction since Pb toxicity increased over five times. X-ray energy dispersive spectroscopy (EDS) was used to confirm lead adsorption on the carbon nanotube oxidized surface. The exposure of Nile tilapia to Pb plus HNO3-MWCNT caused both oxygen consumption and ammonium excretion decrease, when compared to the control. Finally, our results show that carbon nanotubes interact with classical pollutants drawing attention to the environmental implications.

  10. Acute toxicity of low pH to the brown darter Etheostoma edwini under flow-through conditions

    SciTech Connect

    Kase, J.; Burnett, M.; Shortelle, A.B.; Beach, A.

    1995-12-31

    The Okaloosa darter, Etheostoma okaloosae, is found exclusively in the Rocky and Boggy Bayou stream systems entering Choctawhatchee Bay, Florida. Due to its limited range and habitat degradation, E. okaloosae was added to the List of Endangered Species in 1973. The Air Force controls several active test areas situated near streams known to contain Okaloosa darters. The possible release and deposition of strong acids such as hydrochloric acid and hydrofluoric acid to stream surface water during some testing activities has raised concerns that the Okaloosa darter population may be adversely affected by episodic pH depression as a result of testing activities. To evaluate the sensitivity of the Okaloosa darter to pH depression, acute toxicity tests using a closely related species, E. edwini, were conducted. Ninety-six hour and 200 min acute pH depression flow-through toxicity tests were performed with surface water collected from the Rocky Bayou stream system. The 96 h test was conducted using six concentrations held at constant pH throughout the duration of the exposure. The 200 min test used an episodic exposure; pH in the exposure chambers were initially dropped and allowed to return to normal. Mortality data obtained during the studies were used to determine the pH depression necessary to cause 50% mortality (LC50) in each scenario. The 96 h and 200 min LC50 values are, respectively, 3.79 and 2.99 s.u. The 200 min LC50 calculations are based on the lowest achieved pH in each exposure during the test. The results of these tests are part of an effort by the Air Force to make risk-based management decision regarding testing activities.

  11. Toxicity of nitrite to fish: a review

    SciTech Connect

    Lewis, W.M. Jr.; Morris, D.P.

    1986-03-01

    Nitrite, an intermediate in the oxidation of ammonium to nitrate, changes hemoglobin to methemoglobin, which does not carry oxygen; nitrite may thus cause anoxia in fish and other aquatic organisms. The published literature on nitrite toxicity to fish, which consists of about 40 papers, shows that the ratio of the 24-h LC50 (concentration lethal to half of the test organisms in 24 h) to the 96-h LC50 has a median value of 2.0 and is fairly uniform across species; toxicity tests of differing duration can therefore be standardized to a common duration. In general, chronic effects are difficult to detect at concentrations below one-fifth of the 96-h LC50. Most fish concentrate nitrite in fresh water; chloride in the external environment offsets the toxicity of nitrite by competing with nitrite for uptake through the chloride cells of the gills. Bicarbonate also reduces the toxicity of nitrite, but it is less than 1% as effective as chloride. Calcium reduces the toxicity of nitrite, but much less than chloride; the effects of other metal cations have not been studied. Hydrogen ion concentration of the medium has not been shown to have a discrete effect on the toxicity of nitrite except at extreme concentrations uncharacteristic of the environments in which fish ordinarily live. Nitrite toxicity is exacerbated by low oxygen concentrations because nitrite reduces the oxygen-carrying capacity of the blood. Very small fish seem less sensitive to nitrite than fish of intermediate or large size. Present evidence suggests that salmonids are among the fishes most sensitive to nitrite. The least-sensitive species tested thus far are the largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus; the largemouth bass does not concentrate nitrite.

  12. Toxicity of manganese to Ceriodaphnia dubia and Hyalella azteca

    USGS Publications Warehouse

    Lasier, P.J.; Winger, P.V.; Bogenrieder, K.J.

    2000-01-01

    Manganese is a toxic element frequently overlooked when assessing toxicity of effluents, sediments and pore waters. Manganese can be present at toxic levels in anoxic solutions due to its increased solubility under chemically-reducing conditions, and it can remain at those levels for days in aerated test waters due to slow precipitation kinetics. Ceriodaphnia dubia and Hyalella azteca are freshwater organisms often used for toxicity testing and recommended for assessments of effluents and pore waters. Lethal and reproductive-inhibition concentrations of Mn were determined for C. dubia in acute 48h tests and chronic 3-brood tests using animals <24 h old and between 24 and 48 h old. Sensitivity of H. azteca was determined with 7d old animals in acute 96h tests. Tests were run at three levels of water hardness to assess the amelioratory effect, which was often significant. Manganese concentrations were measured analytically at test initiation and after 96 h for calculations of toxicity endpoints and determinations of Mn precipitation during the tests. Minimal amounts of Mn (below 3%) precipitated within 96 h. LC50s determined for H. azteca progressively increased from 3.0 to 8.6 to 13.7 mg Mn/L in soft, moderately-hard and hard waters, respectively. The tolerance of C. dubia to Mn was not significantly different between moderately-hard and hard waters, but was significantly lower in soft water. There was no significant difference in Mn sensitivity between the ages of C. dubia tested. Acute LC50 values for C. dubia averaged 6.2, 14.5 and 15.2 mg Mn/L and chronic IC50 values averaged 3.9, 8.5 and 11.5 mg Mn/L for soft, moderately-hard and hard waters, respectively. Manganese toxicity should be considered when assessing solutions with concentrations near these levels.

  13. Value Added

    ERIC Educational Resources Information Center

    Wilson, M. Roy

    2015-01-01

    With more than a thousand honors programs or colleges in the United States and that number growing every year, defining the value of honors is a significant undertaking. Honors seems to have become an obligatory upgrade that no college or university president can afford to be without, but there is more than institutional trending to be considered,…

  14. Value Added

    ERIC Educational Resources Information Center

    Welch, Matt

    2004-01-01

    This article profiles retiring values teacher Gene Doxey and describes his foundational contributions to the students of California's Ramona Unified School District. Every one of the Ramona Unified School District's 7,200 students is eventually funneled through Doxey's Contemporary Issues class, a required rite of passage between elementary school…

  15. Acute toxicity of Roundup® herbicide to three life stages of the freshwater shrimp Caridina nilotica (Decapoda: Atyidae)

    NASA Astrophysics Data System (ADS)

    Mensah, P. K.; Muller, W. J.; Palmer, C. G.

    Glyphosate based herbicides, including Roundup®, are frequently used in the chemical control of weeds and invading alien plant species in South Africa. These herbicides ultimately get into water courses directly or indirectly through processes such as drifting, leaching, surface runoff and foliar spray of aquatic nuisance plants. Despite their widespread use, no water quality guideline exists to protect indigenous South African freshwater organisms from the toxic effects of these herbicides. The toxicity of the herbicide Roundup® was assessed using three different life stages of the freshwater shrimp Caridina nilotica, a prevalent species in South African freshwater ecosystems. Neonate (<7 days post hatching (dph)), juvenile (>7 dph and <20 dph) and adult (>40 dph) shrimps were exposed to varying concentrations (1.5-50 mg/L acid equivalence (a.e.)) of the herbicide in 48 and 96 h acute toxicity tests in order to determine the most sensitive life-stage. The results showed neonates to be more sensitive to Roundup® than both juveniles and adults with mean 96 h LC 50 values of 2.5, 7.0 and 25.3 mg/L a.e. respectively. The estimated 96 h LC 50 of neonates is much lower than the application rate (20-30 mg/L a.e.), although the application’s impact will depend on the dilution rate of the applied concentration in the environment. All three life-stages of unexposed animals exhibited active and coordinated movement but exposed shrimps were erratic and slow in their movements, with neonates showing most of these behavioral irregularities. This study shows that low levels of the herbicide Roundup® may adversely affect C. nilotica health and survival. Thus, the herbicide should be carefully managed to minimize any negative impact on non-target freshwater organisms.

  16. Tests to determine LC50 and discriminating concentrations for fipronil against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) and their standardization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laboratory test were carried out on larvae and adults of the cattle tick, Rhipicephalus (Boophilus) microplus, to determine fipronil toxicity. Adult immersion test (AIT), larval immersion test (LIT) and larval packet test (LPT) were standardized using susceptible strain (Mozo). Curves dose-response ...

  17. Valuing Stillbirths.

    PubMed

    Phillips, John; Millum, Joseph

    2015-07-01

    Estimates of the burden of disease assess the mortality and morbidity that affect a population by producing summary measures of health such as quality-adjusted life years (QALYs) and disability-adjusted life years (DALYs). These measures typically do not include stillbirths (fetal deaths occurring during the later stages of pregnancy or during labor) among the negative health outcomes they count. Priority-setting decisions that rely on these measures are therefore likely to place little value on preventing the more than three million stillbirths that occur annually worldwide. In contrast, neonatal deaths, which occur in comparable numbers, have a substantial impact on burden of disease estimates and are commonly seen as a pressing health concern. In this article we argue in favor of incorporating unintended fetal deaths that occur late in pregnancy into estimates of the burden of disease. Our argument is based on the similarity between late-term fetuses and newborn infants and the assumption that protecting newborns is important. We respond to four objections to counting stillbirths: (1) that fetuses are not yet part of the population and so their deaths should not be included in measures of population health; (2) that valuing the prevention of stillbirths will undermine women's reproductive rights; (3) that including stillbirths implies that miscarriages (fetal deaths early in pregnancy) should also be included; and (4) that birth itself is in fact ethically significant. We conclude that our proposal is ethically preferable to current practice and, if adopted, is likely to lead to improved decisions about health spending.

  18. Valuing Stillbirths.

    PubMed

    Phillips, John; Millum, Joseph

    2015-07-01

    Estimates of the burden of disease assess the mortality and morbidity that affect a population by producing summary measures of health such as quality-adjusted life years (QALYs) and disability-adjusted life years (DALYs). These measures typically do not include stillbirths (fetal deaths occurring during the later stages of pregnancy or during labor) among the negative health outcomes they count. Priority-setting decisions that rely on these measures are therefore likely to place little value on preventing the more than three million stillbirths that occur annually worldwide. In contrast, neonatal deaths, which occur in comparable numbers, have a substantial impact on burden of disease estimates and are commonly seen as a pressing health concern. In this article we argue in favor of incorporating unintended fetal deaths that occur late in pregnancy into estimates of the burden of disease. Our argument is based on the similarity between late-term fetuses and newborn infants and the assumption that protecting newborns is important. We respond to four objections to counting stillbirths: (1) that fetuses are not yet part of the population and so their deaths should not be included in measures of population health; (2) that valuing the prevention of stillbirths will undermine women's reproductive rights; (3) that including stillbirths implies that miscarriages (fetal deaths early in pregnancy) should also be included; and (4) that birth itself is in fact ethically significant. We conclude that our proposal is ethically preferable to current practice and, if adopted, is likely to lead to improved decisions about health spending. PMID:25395144

  19. Toxic and genotoxic effects of the 2,4-dichlorophenoxyacetic acid (2,4-D)-based herbicide on the Neotropical fish Cnesterodon decemmaculatus.

    PubMed

    Ruiz de Arcaute, C; Soloneski, S; Larramendy, M L

    2016-06-01

    Acute toxicity and genotoxicity of the 54.8% 2,4-D-based commercial herbicide DMA® were assayed on Cnesterodon decemmaculatus (Pisces, Poeciliidae). Whereas lethal effect was used as the end point for mortality, frequency of micronuclei (MNs), other nuclear abnormalities and primary DNA damage evaluated by the single cell gel electrophoresis (SCGE) assay were employed as end points for genotoxicity. Mortality studies demonstrated an LC50 96 h value of 1008 mg/L (range, 929-1070) of 2,4-D. Behavioral changes, e.g., gathering at the bottom of the aquarium, slowness in motion, slow reaction and abnormal swimming were observed. Exposure to 2,4-D within the 252-756 mg/L range increased the frequency of MNs in fish exposed for both 48 and 96 h. Whereas blebbed nuclei were induced in treatments lasting for 48 and 96 h, notched nuclei were only induced in fish exposed for 96 h. Regardless of both concentration and exposure time, 2,4-D did not induce lobed nuclei and binucleated erythrocytes. In addition, we found that exposure to 2,4-D within the 252-756 mg/L range increased the genetic damage index in treatments lasting for either 48 and 96 h. The results represent the first experimental evidence of the lethal and several sublethal effects, including behavioral alterations and two genotoxic properties namely the induction of MNs and primary DNA strand breaks, exerted by 2,4-D on an endemic organism as C. decemmaculatus.

  20. Valuing vaccination

    PubMed Central

    Bärnighausen, Till; Bloom, David E.; Cafiero-Fonseca, Elizabeth T.; O’Brien, Jennifer Carroll

    2014-01-01

    Vaccination has led to remarkable health gains over the last century. However, large coverage gaps remain, which will require significant financial resources and political will to address. In recent years, a compelling line of inquiry has established the economic benefits of health, at both the individual and aggregate levels. Most existing economic evaluations of particular health interventions fail to account for this new research, leading to potentially sizable undervaluation of those interventions. In line with this new research, we set forth a framework for conceptualizing the full benefits of vaccination, including avoided medical care costs, outcome-related productivity gains, behavior-related productivity gains, community health externalities, community economic externalities, and the value of risk reduction and pure health gains. We also review literature highlighting the magnitude of these sources of benefit for different vaccinations. Finally, we outline the steps that need to be taken to implement a broad-approach economic evaluation and discuss the implications of this work for research, policy, and resource allocation for vaccine development and delivery. PMID:25136129

  1. Deriving freshwater quality criteria for copper, cadmium, aluminum and manganese for protection of aquatic life in Malaysia.

    PubMed

    Shuhaimi-Othman, M; Nadzifah, Y; Nur-Amalina, R; Umirah, N S

    2013-03-01

    Freshwater quality criteria for copper (Cu), cadmium (Cd), aluminum (Al), and manganese (Mn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia, which were Macrobrachiumlanchesteri (prawn), two fish -Poeciliareticulata and Rasborasumatrana, Melanoidestuberculata (snail), Stenocyprismajor (ostracod), Chironomusjavanus (midge larvae), Naiselinguis (annelid), and Duttaphrynusmelanostictus (tadpole), to determine 96-h LC50 values for Cu, Cd, Al, and Mn. The final acute values (FAVs) for Cu, Cd, Al, and Mn were 2.5, 3.0, 977.8, and 78.3 μgL(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a Criterion Maximum Concentration (CMC) and a criterion Continuous Concentration (CCC) for Cu, Cd, Al, and Mn of 1.3, 1.5, 488.9, and 39.1 μgL(-1) and 0.3, 0.36, 117.8, and 9.4 μgL(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Cu, Cd, Al, and Mn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that R.sumatrana, M.lanchesteri, C.javanus, and N.elinguis were the most sensitive to Cu, Cd, Al, and Mn, respectively.

  2. Deriving freshwater quality criteria for iron, lead, nickel, and zinc for protection of aquatic life in Malaysia.

    PubMed

    Shuhaimi-Othman, M; Nadzifah, Y; Nur-Amalina, R; Umirah, N S

    2012-01-01

    Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC(50) values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L(-1) and 9.0, 2.0, 19.9, and 36.7 μg L(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC(50) values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively.

  3. Influence of developmental stage, salts and food presence on various end points using Caenorhabditis elegans for aquatic toxicity testing

    SciTech Connect

    Donkin, S.G.; Williams, P.L.

    1995-12-01

    This study used a randomized block design to investigate the importance of several variables in using the free-living soil nematode, Caenorhabditis elegans, for aquatic toxicity testing. Concentration-response data were obtained on nematodes of various developmental stages exposed to four metals (Cd, Pb, Cu, and Hg) and a water-soluble organic toxicant, sodium pentachlorophenate (PCP), under conditions of varied solvent medium (with or without salts and with or without a bacterial food source). The end points measured were 24- and 96-h mortality LC50 value, as well as development of larval stages to adulthood and evidence of reproduction. The results suggest that nematodes of various ages respond similarity to a given toxicant for all end points measured, although adults cultured from eggs appeared more sensitive than adults cultured from dauer larvae. The most important environmental variable in determining toxicity was the medium in which the tests were conducted. The presence of potassium and sodium salts in the medium significantly (p < 0.05) reduced the toxicity of many test samples. The presence of bacteria had little effect on 24-h tests with salts, but was important in 96-h survival and development. Based on sensitivity and ease of handling, adults cultured from eggs are recommended in both 24h and 96-h tests.

  4. The genotoxic effects of the imidacloprid-based insecticide formulation Glacoxan Imida on Montevideo tree frog Hypsiboas pulchellus tadpoles (Anura, Hylidae).

    PubMed

    Pérez-Iglesias, J M; Ruiz de Arcaute, C; Nikoloff, N; Dury, L; Soloneski, S; Natale, G S; Larramendy, M L

    2014-06-01

    The neonicotinoid insecticide imidacloprid (IMI) affects the insect central nervous system and is successfully applied to control pests for a variety of agricultural crops. In the current study, acute toxicity and genotoxicity of the IMI-containing commercial formulation insecticide Glacoxan Imida (35 percent IMI) was evaluated on Hypsiboas pulchellus (Anura: Hylidae) tadpoles exposed under laboratory conditions. A lethal effect was evaluated as the end point for lethality, whereas micronucleus (MN) frequency and DNA single-strand breaks evaluated by the single cell gel electrophoresis (SCGE) assay were employed as end points for genotoxicity. Sublethal end points were assayed within the 12.5-37.5mg/L IMI concentration range. Experiments were performed on tadpoles at stage 36 (range, 35-37) according to the classification proposed by Gosner. Lethality studies revealed an LC50 96h value of 52.622mg/L IMI. Increased frequency of MNs was only observed when 25.0mg/L was assayed for 96h, whereas no other nuclear abnormalities were induced. Increase of the genetic damage index was observed at 48h of treatment within the 12.5-37.5mg/L concentration range, whereas an increased frequency of DNA damage was observed only in tadpoles treated with 37.5mg/L IMI for 96h. This study represents the first evidence of the acute lethal and genotoxic effects exerted by IMI on tadpoles of an amphibian species native to Argentina under laboratory conditions.

  5. Differential modulation of ammonia excretion, Rhesus glycoproteins and ion-regulation in common carp (Cyprinus carpio) following individual and combined exposure to waterborne copper and ammonia.

    PubMed

    Sinha, Amit Kumar; Kapotwe, Mumba; Dabi, Shambel Boki; Montes, Caroline da Silva; Shrivastava, Jyotsna; Blust, Ronny; De Boeck, Gudrun

    2016-01-01

    The main objective of this study was to understand the mode of interaction between waterborne copper (Cu) and high environmental ammonia (HEA) exposure on freshwater fish, and how they influence the toxicity of each other when present together. For this purpose, individual and combined effects of Cu and HEA were examined on selected physiological and ion-regulatory processes and changes at transcript level in the common carp (Cyprinus carpio). Juvenile carp were exposed to 2.6μM Cu (25% of the 96h LC50value) and to 0.65mM ammonia (25% of the 96h LC50value) singly and as a mixture for 12h, 24h, 48h, 84h and 180h. Responses such as ammonia (Jamm) and urea (Jurea) excretion rate, plasma ammonia and urea, plasma ions (Na(+), Cl(-) and K(+)), muscle water content (MWC) as well as branchial Na(+)/K(+)-ATPase (NKA) and H(+)-ATPase activity, and branchial mRNA expression of NKA, H(+)-ATPase, Na(+)/H(+) exchanger (NHE-3) and Rhesus (Rh) glycoproteins were investigated under experimental conditions. Results show that Jamm was inhibited during Cu exposure, while HEA exposed fish were able to increase excretion efficiently. In the combined exposure, Jamm remained at the control levels indicating that Cu and HEA abolished each other's effect. Expression of Rhcg (Rhcg-a and Rhcg-b) mRNA was upregulated during HEA, thereby facilitated ammonia efflux out of gills. On the contrary, Rhcg-a transcript level declined following Cu exposure which might account for Cu induced Jamm inhibition. Likewise, Rhcg-a was also down-regulated in Cu-HEA co-exposed fish whilst a temporary increment was noted for Rhch-b. Fish exposed to HEA displayed pronounced up-regulation in NKA expression and activity and stable plasma ion levels. In both the Cu exposure alone and combined Cu-HEA exposure, ion-osmo homeostasis was adversely affected, exemplified by the significant reduction in plasma [Na(+)] and [Cl(-)], and elevated plasma [K(+)], along with an elevation in MWC. These changes were accompanied

  6. Differential modulation of ammonia excretion, Rhesus glycoproteins and ion-regulation in common carp (Cyprinus carpio) following individual and combined exposure to waterborne copper and ammonia.

    PubMed

    Sinha, Amit Kumar; Kapotwe, Mumba; Dabi, Shambel Boki; Montes, Caroline da Silva; Shrivastava, Jyotsna; Blust, Ronny; De Boeck, Gudrun

    2016-01-01

    The main objective of this study was to understand the mode of interaction between waterborne copper (Cu) and high environmental ammonia (HEA) exposure on freshwater fish, and how they influence the toxicity of each other when present together. For this purpose, individual and combined effects of Cu and HEA were examined on selected physiological and ion-regulatory processes and changes at transcript level in the common carp (Cyprinus carpio). Juvenile carp were exposed to 2.6μM Cu (25% of the 96h LC50value) and to 0.65mM ammonia (25% of the 96h LC50value) singly and as a mixture for 12h, 24h, 48h, 84h and 180h. Responses such as ammonia (Jamm) and urea (Jurea) excretion rate, plasma ammonia and urea, plasma ions (Na(+), Cl(-) and K(+)), muscle water content (MWC) as well as branchial Na(+)/K(+)-ATPase (NKA) and H(+)-ATPase activity, and branchial mRNA expression of NKA, H(+)-ATPase, Na(+)/H(+) exchanger (NHE-3) and Rhesus (Rh) glycoproteins were investigated under experimental conditions. Results show that Jamm was inhibited during Cu exposure, while HEA exposed fish were able to increase excretion efficiently. In the combined exposure, Jamm remained at the control levels indicating that Cu and HEA abolished each other's effect. Expression of Rhcg (Rhcg-a and Rhcg-b) mRNA was upregulated during HEA, thereby facilitated ammonia efflux out of gills. On the contrary, Rhcg-a transcript level declined following Cu exposure which might account for Cu induced Jamm inhibition. Likewise, Rhcg-a was also down-regulated in Cu-HEA co-exposed fish whilst a temporary increment was noted for Rhch-b. Fish exposed to HEA displayed pronounced up-regulation in NKA expression and activity and stable plasma ion levels. In both the Cu exposure alone and combined Cu-HEA exposure, ion-osmo homeostasis was adversely affected, exemplified by the significant reduction in plasma [Na(+)] and [Cl(-)], and elevated plasma [K(+)], along with an elevation in MWC. These changes were accompanied

  7. Toxicity of copper to early-life stage Kootenai River white sturgeon, Columbia River white sturgeon, and rainbow trout

    USGS Publications Warehouse

    Little, E.E.; Calfee, R.D.; Linder, G.

    2012-01-01

    White sturgeon (Acipenser transmontanus) populations throughout western North America are in decline, likely as a result of overharvest, operation of dams, and agricultural and mineral extraction activities in their watersheds. Recruitment failure may reflect the loss of early-life stage fish in spawning areas of the upper Columbia River, which are contaminated with metals from effluents associated with mineral-extraction activities. Early-life stage white sturgeon (A. transmontanus) from the Columbia River and Kootenai River populations were exposed to copper during 96-h flow-through toxicity tests to determine their sensitivity to the metal. Similar tests were conducted with rainbow trout (RBT [Oncorhynchus mykiss]) to assess the comparative sensitivity of this species as a surrogate for white sturgeon. Exposures were conducted with a water quality pH 8.1-8.3, hardness 81-119 mg/L as CaCO2, and dissolved organic carbon 0.2-0.4 mg/L. At approximately 30 days posthatch (dph), sturgeon were highly sensitive to copper with median lethal concentration (LC50) values ranging from 4.1 to 6.8 μg/L compared with 36.5 μg/L for 30 dph RBT. White sturgeon at 123-167 dph were less sensitive to copper with LC50 values ranging from 103.7 to 268.9 μg/L. RBT trout, however, remained more sensitive to copper at 160 dph with an LC50 value of 30.9 μg/L. The results indicate that high sensitivity to copper in early-life stage white sturgeon may be a factor in recruitment failure occurring in the upper Columbia and Kootenai rivers. When site-specific water-quality criteria were estimated using the biotic ligand model (BLM), derived values were not protective of early-life stage fish, nor were estimates derived by water-hardness adjustment.

  8. The mysid Siriella armata as a model organism in marine ecotoxicology: comparative acute toxicity sensitivity with Daphnia magna.

    PubMed

    Pérez, Sara; Beiras, Ricardo

    2010-01-01

    Siriella armata (Crustacea, Mysidacea) is a component of the coastal zooplankton that lives in swarms in the shallow waters of the European neritic zone, from the North Sea to the Mediterranean. Juveniles of this species were examined as standard test organisms for use in marine acute toxicity tests. The effects of reference toxicants, three trace metals (Copper, Cadmium and Zinc), and one surfactant, sodium dodecyl sulfate (SDS) were studied on S. armata neonates (\\24 h) reared in the laboratory. Acute toxicity tests were carried out with filtered sea water on individual chambers (microplate wells for metals or glass vials for SDS) incubated in an isothermal room at 20 degrees C, with 16 h light: 8 h dark photoperiod for 96 h. Each neonate was fed daily with 10-15 nauplii of Artemia salina. Acute (96 h) LC50 values, in increasing order, were 46.9 lg/L for Cu, 99.3 lg/L for Cd, 466.7 lg/L for Zn and 8.5 mg/L for SDS. The LC(10), NOEC and LOEC values were also calculated. Results were compared with Daphnia magna, a freshwater cladoceran widely used as a standard ecotoxicological test organism. Acute (48 h) LC(50) values were 56.2 lg/L for Cu, 571.5 lg/L for Cd, 1.3 mg/L for Zn and 27.3 mg/L for SDS. For all the reference toxicants studied, the marine mysid Siriella armata showed higher sensitivity than the freshwater model organism Daphnia magna, validating the use of Siriella mysids as model organisms in marine acute toxicity tests.

  9. The acute and chronic toxicity of cadmium and zinc to two hydra species.

    PubMed

    Holdway, D A; Lok, K; Semaan, M

    2001-01-01

    The potential of two hydra species, Hydra vulgaris (pink) and Hydra viridissima (green), for use as invertebrate models for toxicity testing of waterborne metals was investigated. The acute and subchronic toxicities of cadmium (a nonessential metal) and zinc (an essential metal) were determined. Results showed that both the hydra species were more sensitive to cadmium than to zinc, and that green hydra were more sensitive than pink hydra. The mean (SE) 96 h LC50 values of cadmium and zinc for pink hydra were 83 (8.5) and 2300 (150) micrograms/L, respectively. For green hydra, the respective 96 h LC50 values for cadmium and zinc were 3.0 (0.0) and 935 (46.5) micrograms/L. The respective 7-day no-observed-effect-concentrations (NOEC) and lowest-observed-effect-concentrations (LOEC) for pink hydra were < 13 and 13 micrograms/L for cadmium, and < 250 and 250 micrograms/L for zinc. The respective 7-day NOEC and LOEC values for green hydra were 0.4 and 0.8, microgram/L for cadmium, and 38 and 75 micrograms/L for zinc. Neither 1, 2, or 3 x 90-min pulse-exposures to 0.4, 0.8, or 1.5 micrograms/L of cadmium had any significant deleterious effect on total green hydra numbers after seven days in clean water. Green hydra appeared to be excellent freshwater invertebrate models for testing dissolved metals based on their sensitivity and the ability to rapidly assess population reproduction in the laboratory.

  10. Acute toxicity of 54 industrial chemicals to sheepshead minnows (Cyprinodon variegatus)

    SciTech Connect

    Heitmuller, P.T.; Hollister, T.A.; Parrish, P.R.

    1981-12-01

    Toxicity tests were conducted with sheepshead minnows to develop a data base from which water quality criteria could be established and to help determine priorites for further reseach efforts. Chemicals were generally those used by industry in relatively large quantities that pose potential or suspected environmental hazards, such as, chlorinated benzenes, phenols, and phthalates. The acute toxicity of the 54 chemicals varied widely. The most toxic chemical groups were the chlorinated phenols and the chlorinated benzenes with 96-h LC50's (based on nominal concentrations) ranging from 1.7-5.4 ppm and 0.8-21 ppm, respectively. The most toxic chemical tested appeared to be 1,2,4,5-tetrachlorobenzene with a 96-h LC50 of 0.8 ppm (95% confidence limits of 0.7-1.1 ppm). The 96-h LC50 for pentachlorobenzene was the same (0.8 ppm; 95% confidence limits of 0.4-1.8 ppm), but its effect early in the exposure was not as severe as the effect of 1,2,4,5-tetrachlorobenzene. The majority of the chemicals had 96-h LC50's in the range of 10-500 ppm and were considered to be slightly toxic to practically nontoxic. Ten of the chemicals had no apparent effect at highest concentrations tested. (JMT)

  11. A COMPARISON OF THE LETHAL AND SUBLETHAL TOXICITY OF ORGANIC CHEMICAL MIXTURES TO THE FATHEAD MINNOW (PIMEPHALES PROMELAS)

    EPA Science Inventory

    The joint toxic effects of known binary and multiple organic chemical mixtures to the fathead minnow (Pimephales promelas) were defined at both the 96-h 50% lethal effect concentration (LC50) and sublethal (32-d growth) response levels for toxicants with a narcosis I, narcosis II...

  12. PREDICTION OF THE ACUTE TOXICITY OF ORGANIC COMPOUNDS TO THE FATHEAD MINNOW (PIMEPHALES PROMALAS) USING A GROUP CONTRIBUTION METHOD

    EPA Science Inventory

    A group contribution method has been developed to correlate the acute toxicity (96 h LC50) to the fathead minnow (Pimephales promelas) for 379 organic chemicals. Multilinear regression and computational neural networks (CNNs) were used for model building. The multilinear linear m...

  13. Water chemistry influences the toxicity of silver to the green-lipped mussel Perna viridis.

    PubMed

    Vijayavel, Kannappan

    2010-08-01

    The study determined the influence and relative importance of water chemistry parameters (pH, alkalinity, hardness) on the acute toxicity of silver to the green mussel Perna viridis. A preliminary bioassay revealed that 4 mg L(-1) of silver caused 50% mortality (LC50) in 96 h for mussels placed in seawater with pH 8.5, hardness 1,872 mg L(-1), and alkalinity 172 mg L(-1). Mortality of mussels increased with decreasing pH and increasing hardness and alkalinity variables. In contrast the mortality decreased with increasing pH and decreasing hardness and alkalinity values. The water chemistry also affected the concentration of silver in experimental seawater and bioaccumulation of silver in mussels. The results revealed that the chemical properties of seawater must be considered while conducting toxicity tests with metals like silver. The possible explanations for the influence of water chemistry on silver toxicity to P. viridis are discussed.

  14. Copper acute toxicity tests with Schizothorax o'connori Lloyd and Schizothorax waltoni Regan: a biomonitor of heavy metal pollution in a high altitude area?

    PubMed

    Shao, Jian; Xie, Congxin; Qin, Jianhui; Huo, Bin; Luo, Yangzhi

    2014-09-01

    Fingerlings of two different Schizothorax species, S. o'connori Lloyd and S. waltoni Regan, were exposed to copper for 264 h in a series of static toxicity tests. The mortality rates of these two species increased as the exposure concentrations increased and the exposure time was prolonged. Estimated 96 h median lethal concentration (LC50) values were 0.31 and 0.28 mg/L for the two species, respectively. These findings indicated that fingerlings of these species were sensitive to copper, and that both species may be suitable for use as local biomonitors of copper pollution in the high altitude environment. However, S. waltoni may be more useful in indicating the safe concentrations of copper used in aquaculture for therapeutic purposes. Further quantitative studies with measured concentrations of copper are required to verify the results observed in the present study.

  15. Physiological effects of metal toxicity on the tropical freshwater shrimp Microbrachium carcinus (Linneo, 1758).

    PubMed

    Correa, M

    1987-01-01

    Pilot tests were performed to determine the level at which Zn(++) and Cu(++) ceased to be acutely toxic in Macrobrachium carcinus. The data indicated that the static 96h-LC(50) values for Zn(++) and Cu(++) were 0.2 and 0.1 mg litre(-1) respectively. A differential reduction in respiration and ammonia excretion rates was noted with increasing concentrations of these metals in the water. These levels may in a toxic body burden and a progressive deterioration of gill efficiency. A decrease in respiration and ammonia excretion rates resulted in a decrease in O:N ratios, upon exposure to Zn(++) and Cu(++) concentrations. The ratios obtained indicate that these metals, also increased dependence on carbohydrate or lipid reserves.

  16. Toxicity of endosulfan to Atalophlebia spp. (Ephemeroptera) in the laboratory, mesocosm, and field.

    PubMed

    Hose, Grant C; Hyne, Ross V; Lim, Richard P

    2003-12-01

    A series of single-species toxicity tests was conducted in the laboratory and in outdoor stream mesocosms. The mayfly nymphs of Atalophlebia spp. (A. av2 and A. av6) were exposed to the organochlorine pesticide endosulfan for either 12- or 48-h periods, with mortality recorded after 96 h. For both exposure periods, the lethal concentration (LC50 and LC 10) values were not significantly different between laboratory and mesocosm single-species tests, suggesting that the absence of natural environmental conditions and biological interactions in laboratory single-species tests did not influence the toxicity of technical endosulfan to Atalophlebia spp. Interpolation of toxicity test data indicates that peak endosulfan concentrations recorded in the rivers during storm events are likely to cause only minimal impact on Atalophlebia spp. populations. This suggests that changes in the abundance of populations observed in the field, if due to total endosulfan alone, are the result of chronic rather than acute exposure.

  17. Subacute toxicity assessment of water disinfection byproducts on zebrafish.

    PubMed

    Rácz, Gergely; Csenki, Zsolt; Kovács, Róbert; Hegyi, Arpád; Baska, Ferenc; Sujbert, László; Zsákovics, Ivett; Kis, Renáta; Gustafson, Ryan; Urbányi, Béla; Szende, Béla

    2012-07-01

    Disinfection of raw water is essential to the production of drinking water. However, by-products of disinfection may exert toxic effects. The potential toxic effects of two of these compounds, 4-ethylbenzaldehyde (EBA) and 2,4-difluoroaniline (DFA) were investigated using the zebrafish (Danio rerio) model. The two compounds, dissolved, were introduced in duplicate aquariums containing zebrafish in two different concentrations based on LC50 values. The aquarium water containing EBA or DFA was changed every 96 h throughout the 3 months of treatment. Behavior of the fish in each replicate was inspected twice daily. In course of treatment with both concentrations, fish exposed to DFA displayed behavior associated with visible anxiety, while EBA treated were lethargic and did not evade capture. Application of both concentrations of each component into the aquarium water resulted in dystrophic lesions in the liver, kidney and skin of the fish while preneoplastic lesions and tumors were not observed. PMID:22161134

  18. Fish embryo toxicity test: identification of compounds with weak toxicity and analysis of behavioral effects to improve prediction of acute toxicity for neurotoxic compounds.

    PubMed

    Klüver, Nils; König, Maria; Ortmann, Julia; Massei, Riccardo; Paschke, Albrecht; Kühne, Ralph; Scholz, Stefan

    2015-06-01

    The fish embryo toxicity test has been proposed as an alternative for the acute fish toxicity test, but concerns have been raised for its predictivity given that a few compounds have been shown to exhibit a weak acute toxicity in the fish embryo. In order to better define the applicability domain and improve the predictive capacity of the fish embryo test, we performed a systematic analysis of existing fish embryo and acute fish toxicity data. A correlation analysis of a total of 153 compounds identified 28 compounds with a weaker or no toxicity in the fish embryo test. Eleven of these compounds exhibited a neurotoxic mode of action. We selected a subset of eight compounds with weaker or no embryo toxicity (cyanazine, picloram, aldicarb, azinphos-methyl, dieldrin, diquat dibromide, endosulfan, and esfenvalerate) to study toxicokinetics and a neurotoxic mode of action as potential reasons for the deviating fish embryo toxicity. Published fish embryo LC50 values were confirmed by experimental analysis of zebrafish embryo LC50 according to OECD guideline 236. Except for diquat dibromide, internal concentration analysis did not indicate a potential relation of the low sensitivity of fish embryos to a limited uptake of the compounds. Analysis of locomotor activity of diquat dibromide and the neurotoxic compounds in 98 hpf embryos (exposed for 96 h) indicated a specific effect on behavior (embryonic movement) for the neurotoxic compounds. The EC50s of behavior for neurotoxic compounds were close to the acute fish toxicity LC50. Our data provided the first evidence that the applicability domain of the fish embryo test (LC50s determination) may exclude neurotoxic compounds. However, neurotoxic compounds could be identified by changes in embryonic locomotion. Although a quantitative prediction of acute fish toxicity LC50 using behavioral assays in fish embryos may not yet be possible, the identification of neurotoxicity could trigger the conduction of a conventional fish

  19. Use of neomysis mercedis (crustacea: mysidacea) for estuarine toxicity tests

    SciTech Connect

    Brandt, O.M.; Fujimura, R.W.; Finlayson, B.J. )

    1993-03-01

    The mysid Neomysis mercedis was examined as a test organism for use in acute toxicity tests at intermediate salinities characteristic of estuarine waters. Several sensitive invertebrate species are available for marine assessments (mysids) and freshwater tests (cladocerans), but few are available for estuarine toxicity tests. Observations in the laboratory indicate that Neomysis mercedis can be reared successfully at a temperature of 17[degrees]C, a salinity of 2%, and a population density less than 5/L. Brine shrimp nauplii Artemia salina, algae, and commercial foods were used to sustain mysid cultures. Neomysis mercedis is vivaparous and can complete its life cycle in 3-4 months. Neomysis mercedis is as sensitive as or more sensitive to toxicants than the marine mysid Mysidopsis bahia and the freshwater cladocerans Daphnia magna, Ceriodaphnia dubia, and Simocephalus serrulatus. The mean 96-h LC50 values (concentrations lethal to half the test animals) for N. mercedis, in increasing order, were 0.20 [mu]g/L for thiobencarb, and for malathion, 14 [mu]g/L for carbofuran, 150 [mu]g/L for copper sulfate, 280 [mu]g/L for thiobencarb, and 1,600 [mu]g/L for molinate. Neonates (5 d postrelease) were generally more sensitive than older juveniles. Coefficients of variation (100[center dot]SD/mean) of LC50 values varied from 21 to 35%. 37 refs., 2 figs., 7 tabs.

  20. Acute toxic effects of the herbicide formulation and the active ingredient used in cycloxydim-tolerant maize cultivation on embryos and larvae of the African clawed frog, Xenopus laevis.

    PubMed

    Wagner, Norman; Lötters, Stefan; Veith, Michael; Viertel, Bruno

    2015-04-01

    Most genetically engineered herbicide-tolerant crops are still awaiting approval in Europe. There is, however, a recent trend for the cultivation of cycloxydim-tolerant maize hybrids for use in maize production. We studied the acute toxic effects of the complementary herbicide Focus(®) Ultra and its active ingredient cycloxydim on embryos and early-stage larvae of the African clawed frog (Xenopus laevis). The results indicate that the herbicide formulation is significantly more toxic than the active ingredient alone. Therefore, it is suggested that the added substances either solely or in a synergistic action with the active ingredient are responsible for adverse effects. The formulation was found to be moderately toxic to embryos but highly toxic to early larvae. Based on calculated teratogenic indices, both cycloxydim and Focus(®) Ultra seem to be non-teratogenic and also the minimum Focus(®) Ultra concentration to inhibit growth in embryos and larvae was close to the LC50 values. The data suggest that tests with the rainbow trout are not in all cases appropriate to assess the risk in aquatically developing anurans. This is demonstrated by 96-h LC50 values, which are for rainbow trout more than 50- to 20-fold higher than for early X. laevis larvae. However, based on worst-case predicted environmental concentrations for surface waters, there is apparently a large safety margin in field use of Focus(®) Ultra if buffer strips between the farm land and the amphibian habitats are regarded. PMID:25634323

  1. Acute toxicity of ammonia (NH3-N) in sewage effluent to Chironomus riparius: II. Using a generalized linear model

    USGS Publications Warehouse

    Monda, D.P.; Galat, D.L.; Finger, S.E.; Kaiser, M.S.

    1995-01-01

    Toxicity of un-ionized ammonia (NH3-N) to the midge, Chironomus riparius was compared, using laboratory culture (well) water and sewage effluent (≈0.4 mg/L NH3-N) in two 96-h, static-renewal toxicity experiments. A generalized linear model was used for data analysis. For the first and second experiments, respectively, LC50 values were 9.4 mg/L (Test 1A) and 6.6 mg/L (Test 2A) for ammonia in well water, and 7.8 mg/L (Test 1B) and 4.1 mg/L (Test 2B) for ammonia in sewage effluent. Slopes of dose-response curves for Tests 1A and 2A were equal, but mortality occurred at lower NH3-N concentrations in Test 2A (unequal intercepts). Response ofC. riparius to NH3 in effluent was not consistent; dose-response curves for tests 1B and 2B differed in slope and intercept. Nevertheless, C. riparius was more sensitive to ammonia in effluent than in well water in both experiments, indicating a synergistic effect of ammonia in sewage effluent. These results demonstrate the advantages of analyzing the organisms entire range of response, as opposed to generating LC50 values, which represent only one point on the dose-response curve.

  2. Contaminant exposures in various environmental media: How can toxicity comparisons be made?

    SciTech Connect

    Lanno, R.P.; McCarty, L.S.

    1995-12-31

    Environmental protection is usually based upon guidelines or standards expressed as chemical values in environmental media such as air, sediment, soil, and water. The basis for such guidelines is laboratory toxicity test data, often time-dependent LC50 values (e.g., 96-h LC50s), where toxicity is expressed in terms of the concentration of chemical contaminant in the exposure medium. This preoccupation with exposure-based estimates of toxic dose has led to many difficulties when attempting to compare the relative toxicity of compounds between species and under various modifying conditions in the same medium. Furthermore, viable comparisons of toxic potencies between organisms inhabiting different environmental media has been all but impossible. This paper exploits the relationship between body residues and adverse biological effects to compare the effects of certain modifying factors (e.g., temperature) on expressed toxicity and toxic potency both within and between different species in one medium. As well, this approach is used to make comparisons of toxic potency between different species in different environmental media. Such comparisons are made by standardizing toxic responses to time-independent toxicity thresholds and using the critical body residue at the chosen biological response endpoint as the dose surrogate rather than the concentration of chemical in the exposure medium. Comparisons of exposure-based and organism residue-based toxicity between fish, and invertebrates in soil (earthworms) and sediment (amphipods) are presented. Recommendations to facilitate such comparisons are reviewed.

  3. Toxicity of hexahydro-1,3,5-trinitro-1,3,5-triazine to larval zebrafish (Danio rerio)

    USGS Publications Warehouse

    Mukhi, S.; Pan, X.; Cobb, G.P.; Patino, R.

    2005-01-01

    Hexahydro-1,3,5-trinitro-1,3,5-triazine, a cyclonitramine commonly known as RDX, is used in the production of military munitions. Contamination of soil, sediment, and ground and surface waters with RDX has been reported in different places around the world. Acute and subacute toxicities of RDX have been relatively well documented in terrestrial vertebrates, but among aquatic vertebrates the information available is limited. The objective of this study was to characterize the acute toxicity of RDX to larval zebrafish. Mortality (LC50) and incidence of vertebral column deformities (EC50) were two of the end points measured in this study. The 96-h LC50 was estimated at 22.98 and 25.64 mg l-1 in two different tests. The estimated no-observed-effective- concentration (NOEC) values of RDX on lethality were 13.27 ?? 0.05 and 15.32 ?? 0.30 mg l-1; and the lowest-observed-effective- concentration (LOEC) values were 16.52 ?? 0.05 and 19.09 ?? 0.23 mg l-1 in these two tests, respectively. The 96-h EC50 for vertebral deformities on survivors from one of the acute lethality tests was estimated at 20.84 mg l-1, with NOEC and LOEC of 9.75 ?? 0.34 and 12.84 ?? 0.34 mg l-1, respectively. Behavioral aberrations were also noted in this acute toxicity study, including the occurrence of whirling movement and lethargic behavior. The acute effects of RDX on survival, incidence of deformities, and behavior of larval zebrafish occurred at the high end of the most frequently reported concentrations of RDX in aquatic environments. The chronic effects of RDX in aquatic vertebrates need to be determined for an adequate assessment of the ecological risk of environmental RDX. ?? 2005 Elsevier Ltd. All rights reserved.

  4. Comparative toxicity of two glyphosate formulations (original formulation of Roundup® and Roundup WeatherMAX®) to six North American larval anurans.

    PubMed

    Fuentes, Latice; Moore, Lindsay J; Rodgers, John H; Bowerman, William W; Yarrow, Gregory K; Chao, Wayne Y

    2011-12-01

    The toxicity of two glyphosate formulations (the original formulation of Roundup® and Roundup WeatherMAX®) to six species of North American larval anurans was evaluated by using 96-h static, nonrenewal aqueous exposures. The 96-h median lethal concentration values (LC50) ranged from 1.80 to 4.22 mg acid equivalent (ae)/L and 1.96 to 3.26 mg ae/L for the original formulation of Roundup and Roundup WeatherMAX, respectively. Judged by LC50 values, four species were more sensitive to Roundup WeatherMAX exposures, and two species were more sensitive to the original formulation. Two of six species, Bufo fowleri (p < 0.05, F = 14.89, degrees of freedom [df] = 1) and Rana clamitans (p < 0.05, F = 18.46, df = 1), had significantly different responses to the two formulations tested. Increased sensitivity to Roundup WeatherMAX likely was due to differences in the surfactants or relative amounts of the surfactants in the two formulations. Potency slopes for exposures of the original formulation ranged from 24.3 to 92.5% mortality/mg ae/L. Thresholds ranged from 1.31 to 3.68 mg ae/L, showing an approximately three times difference in the initiation of response among species tested. For exposures of Roundup WeatherMAX, slopes ranged from 49.3 to 84.2% mortality/mg ae/L. Thresholds ranged from 0.83 to 2.68 mg ae/L. Margins of safety derived from a simulated direct overspray were above 1, except for one species in exposures of Roundup WeatherMAX. Laboratory data based on aqueous exposures are conservative because of the lack of environmental ligands; however, these tests provide information regarding the relative toxicity between these two Roundup formulations.

  5. Survival, osmoregulation and ammonia-N excretion of blue swimmer crab, Portunus pelagicus, juveniles exposed to different ammonia-N and salinity combinations.

    PubMed

    Romano, Nicholas; Zeng, Chaoshu

    2010-03-01

    Ammonia-N toxicity to early Portunus pelagicus juveniles at different salinities was investigated along with changes to haemolymph osmolality, Na(+), K(+), Ca(2+) and ammonia-N levels, ammonia-N excretion and gill Na(+)/K(+)-ATPase activity. Experimental crabs were acclimated to salinities 15, 30 and 45 per thousand for one week and 25 replicate crabs were subsequently exposed to 0, 20, 40, 60, 80, 100 and 120 mg L(-1) ammonia-N for 96-h, respectively. High ammonia-N concentrations were used to determine LC(50) values while physiological measurements were conducted at lower concentrations. When crabs were exposed to ammonia-N, anterior gill Na(+)/K(+)-ATPase activity significantly increased (p<0.05) at all salinities, while this only occurred on the posterior gills at 30 per thousand. For crabs exposed to 20 and 40 mg L(-1) ammonia-N, both posterior gill Na(+)/K(+)-ATPase activity and ammonia-N excretion were significantly higher at 15 per thousand than those at 45 per thousand. Despite this trend, the 96-h LC(50) value at 15 per thousand (43.4 mg L(-1)) was significantly lower (p<0.05) than at both 30 per thousand and 45 per thousand (65.8 and 75.2 mg L(-1), respectively). This may be due to significantly higher (p<0.05) haemolymph ammonia-N levels of crabs at low salinities and may similarly explain the general ammonia-N toxicity pattern to other crustacean species.

  6. Lethal levels of selected water quality variables to larval and juvenile Lost River and shortnose suckers

    USGS Publications Warehouse

    Saiki, M.K.; Monda, D.P.; Bellerud, B.L.

    1999-01-01

    Resource managers hypothesize that occasional fish kills during summer-early fall in Upper Klamath Lake, Oregon, may be linked to unfavorable water quality conditions created by massive algal blooms. In a preliminary effort to address this concern, short-term (96-h-long) laboratory tests were conducted with larval and juvenile Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) suckers to determine the upper median lethal concentrations (LC50s; also referred to as median tolerance limits) for pH, un-ionized ammonia, and water temperature, and the lower LC50s for dissolved oxygen. The mean LC50s varied among species and life stages as follows: for pH, 10.30-10.39; for un-ionized ammonia, 0.48-1.06 mg litre-1; for temperature, 30.35-31.82??C; and for dissolved oxygen, 1.34-2.10 mg litre-1. Comparisons of 95% confidence limits indicated that, on average, the 96-h LC50s were not significantly different from those computed for shorter exposure times (i.e., 24 h, 48 h, and 72 h). According to two-way analysis of variance, LC50s for the four water quality variables did not vary significantly (p > 0.05) between fish species. However, LC50s for pH (exposure times of 24 h and 48 h) and dissolved oxygen (exposure times of 48 h, 72 h, and 96 h) differed significantly (p ??? 0.05) between life stages, whereas LC50s for un-ionized ammonia and water temperature did not exhibit significant differences. In general, larvae were more sensitive than juveniles to high pH and low dissolved oxygen concentrations. When compared to ambient water quality conditions in Upper Klamath Lake, our results strongly suggest that near-anoxic conditions associated with the senescence phase of algal blooms are most likely to cause high mortalities of larval and juvenile suckers.

  7. Evaluation of the genotoxicity of a herbicide formulation containing 3,6-dichloro-2-metoxybenzoic acid (dicamba) in circulating blood cells of the tropical fish Cnesterodon decemmaculatus.

    PubMed

    Ruiz de Arcaute, C; Soloneski, S; Larramendy, M L

    2014-10-01

    Acute toxicity and genotoxicity of the dicamba-based commercial herbicide formulation Banvel(®) were evaluated on Cnesterodon decemmaculatus (Pisces, Poeciliidae) exposed under laboratory conditions. A lethal effect was used as the end point for mortality, whereas frequency of micronuclei (MNs) and DNA single-strand breaks evaluated by the single cell gel electrophoresis assay were employed as end points for genotoxicity. Mortality studies revealed an LC50 96 h value of 1639 mg/L (range, 1471-1808) of dicamba. Furthermore, behavioral changes, e.g., gathering at the bottom of the aquarium, slowness in motion, abnormal swimming, and slow reaction, were observed. Whereas increased frequency of MNs was observed when 1229 mg/L dicamba was assayed for 48 h, no induction of MNs was observed in fish exposed to the herbicide for 96 h, regardless of the concentration of dicamba. Furthermore, other nuclear abnormalities, i.e., binucleated cells and lobed and notched nuclei, were induced in fish exposed for 48 h but not 96 h. Increase in the genetic damage index was observed in those treatments (lasting for both 48 and 96 h) within the 410-1229 mg/L dicamba concentration-range. This study represents the first evidence of acute lethal and sublethal effects exerted by dicamba on a piscine species native to Argentina. The results could indicate that dicamba-based formulation Banvel(®) is the less toxic emerging pollutant reported so far for C. decemmaculatus. Finally, our findings highlight the properties of this herbicide that jeopardize nontarget living species exposed to this agrochemical.

  8. Deleterious effects of water-soluble fraction of petroleum, diesel and gasoline on marine pejerrey Odontesthes argentinensis larvae.

    PubMed

    Rodrigues, Ricardo Vieira; Miranda-Filho, Kleber Campos; Gusmão, Emeline Pereira; Moreira, Cauê Bonucci; Romano, Luis Alberto; Sampaio, Luís André

    2010-04-01

    Accidental discharges and oil spills are frequent around the world. Petroleum-derived hydrocarbons are considered one of the main pollutants of aquatic ecosystem. The importance of petroleum and refined fuels is notorious because today's society depends on them. Researches related to the toxic water-soluble fraction (WSF) of petroleum and derivatives to aquatic biota are scarce. For this reason, deleterious effects of WSF of Brazilian petroleum, automotive diesel and unleaded gasoline to marine pejerrey Odontesthes argentinensis larvae were studied employing toxicity tests and histopathological examination. Each WSF was generated in a laboratory by mixing four parts of seawater with one part of pollutant by approximately 22 h. Larvae were exposed during 96 h to different concentrations of WSF of petroleum, diesel, and gasoline, plus a control. After 96 h of exposure to the different WSFs, three larvae were sampled for histopathological studies. The median lethal concentration after 96 h (LC50) of exposure for WSF of petroleum was equal to 70.68%, it was significantly higher (P<0.05) than the values for WSF of diesel and gasoline, which were 13.46% and 5.48%, respectively. The histological examination of pejerrey larvae exposed to WSF of petroleum, diesel and gasoline after 96 h revealed a variety of lesions in the larvae. The gills, pseudobranchs and esophagus presented epithelial hyperplasia, and the liver presented dilatation of hepatic sinusoids, hepatocitomegaly, bi-nucleated and nuclear degeneration of hepatocytes, such as pyknotic nuclei. The acute toxicity of diesel and gasoline is at least fivefold higher than Brazilian petroleum. However, all toxicants induced histopathological abnormalities in pejerrey larvae. The results are of importance since much attention has been paid to large visible surfaces of petroleum spills instead of potential toxic effects of dissolved aromatic hydrocarbons, which are more available to marine biota.

  9. Toxic and genotoxic effects of the imazethapyr-based herbicide formulation Pivot H® on montevideo tree frog Hypsiboas pulchellus tadpoles (Anura, Hylidae).

    PubMed

    Pérez-Iglesias, J M; Soloneski, S; Nikoloff, N; Natale, G S; Larramendy, M L

    2015-09-01

    Acute lethal and sublethal toxicity of the imidazolinone imazethapyr (IMZT)-based commercial formulation herbicide Pivot H® (10.59% IMZT) was evaluated on Hypsiboas pulchellus tadpoles. Whereas mortality was used as the end point for lethality, frequency of micronuclei (MNs) and other nuclear abnormalities as well as DNA single-strand breaks evaluated by the single cell gel electrophoresis assay were employed to test genotoxicity. Behavioral, growth, developmental, and morphological abnormalities were also employed as sublethal end points. Mortality studies revealed equivalent LC50 (96h) values of 1.49mg/L (confidence limit, 1.09-1.63) and 1.55mg/L (confidence limit, 1.51-1.60) IMZT for Gosner stage (GS) 25 and GS36, respectively. Behavioral changes, i.e., irregular swimming and immobility, as well as a decreased frequency of keratodonts were observed. The herbicide increased the frequency of MNs in circulating erythrocytes of tadpoles exposed for 48h to the highest concentration assayed (1.17mg/L). However, regardless of the concentration of the herbicide assayed, an enhanced frequency of MNs was observed in tadpoles exposed for 96h. The herbicide was able to induce other nuclear abnormalities, i.e., blebbed and notched nuclei, only when tadpoles were exposed for 96h. In addition, we observed that exposure to IMZT within the 0.39-1.17mg/L range increased the genetic damage index in treatments lasting for both 48 and 96h. This study represents the first evidence of acute lethal and sublethal effects exerted by IMZT on amphibians. Finally, our findings highlight the properties of this herbicide that jeopardize nontarget living species exposed to IMZT.

  10. Effects of the herbicides clomazone, quinclorac, and metsulfuron methyl on acetylcholinesterase activity in the silver catfish (Rhamdia quelen) (Heptapteridae).

    PubMed

    dos Santos Miron, Denise; Crestani, Márcia; Rosa Shettinger, Maria; Maria Morsch, Vera; Baldisserotto, Bernardo; Angel Tierno, Miguel; Moraes, Gilberto; Vieira, Vania Lucia Pimentel

    2005-07-01

    Fingerlings of the silver catfish (Rhamdia quelen) were exposed to three herbicides widely used in rice culture in south Brazil: clomazone, quinclorac, and metsulfuron methyl. LC50 was determined and acetylcholinesterase (AChE) activity was evaluated in brain and muscle tissue of fish exposed to different herbicide concentrations after 96h (short term). The LC50 value (nominal concentration) was 7.32 mg/L for clomazone and 395 mg/L for quinclorac, but was not obtained for metsulfuron-methyl since all fingerlings survived the highest concentration of 1200 mg/L. Brain and muscle AChE activity in unexposed fish were 17.9 and 9.08 micromol/min/g protein, respectively. Clomazone significantly inhibited AChE activity in both tissues, achieving maximal inhibition of about 83% in brain and 89% in muscle tissue. In contrast, quinclorac and metsulfuron methyl caused increases in enzyme activity in the brain (98 and 179%, respectively) and inhibitions in muscle tissue (88 and 56%, respectively). This study demonstrated short-term effects of exposure to environmentally relevant concentrations of rice field herbicides on AChE activity in brain and muscle tissue of silver catfish.

  11. Adaptation to fluoranthene exposure in a laboratory population of fathead minnows

    SciTech Connect

    Diamond, S.A.; Oris, J.T.; Guttman, S.I.

    1995-08-01

    Tolerance of toxicant exposure is common in polluted sites in nature. However, in most cases, the processes underlying tolerance acquisition are not well understood. In the case of exposure to polycyclic aromatic hydrocarbons (PAHs) in particular, reports are lacking on the capacity for tolerance acquisition. To evaluate the potential for adaptation to this class of contaminants the authors exposed a large laboratory population of fathead minnows to fluoranthene, commonly a major constituent of PAH contamination. The exposure concentration chosen did not cause mortality but was sufficient to diminish reproductive capacity in exposed breeding fish relative to a control population. This level of exposure also significantly diminished hatching success and larval survivorship in the exposed population. The estimated value of selection against susceptibility (the product of all assessments of effect) was 0.67. Tests for tolerance acquisition included comparative larval 96-h LC50 determinations, and comparative juvenile median time to death (LT50) determinations. Enhanced tolerance was not apparent in the LC50 determinations, although an examination of the concentration-response distribution suggested an adverse effect due to egg and larval exposure to fluoranthene prior to the test. In contrast, results of the comparative LT50 determination indicated that the exposed population was approximately 30% more tolerant, relative to the control population, when exposed to an acutely toxic concentration of fluoranthene. These results suggest that tolerance to PAH exposure can occur in nature and that this population-level response needs to be examined relative to other recognized effects in PAH-contaminated areas.

  12. Lethal and sublethal effects of the sediment-associated PCB Aroclor 1254 on a meiobenthic copepod

    SciTech Connect

    DiPinto, L.M.; Coull, B.C.; Chandler, G.T. . Dept. of Environmental Health Sciences, Marine Science Program, and Belle W. Baruch Inst. for Marine Biology and Coastal Research)

    1993-10-01

    Acute toxicity tests were performed on field-collected copepods (Microarthridion littorale) using the sediment-associated polychlorinated biphenyl (PCB) Aroclor 1254 (i.e., PCB concentrations in bulk sediments in the bound and/or unbound states). Three replicates of 50 adult copepods were exposed to five levels of PCB-contaminated sediments for 96 h and compared to untreated controls and solvent controls. LC50 concentrations were nearly twice as high for females as for males. To determine the effects of the PCB on reproductive output of the copepods, copulating pairs of Microarthridion littorale were allowed to reproduce in concentrations of Aroclor 1254-contaminated sediments below LC50 values. Two experimental trials with 10 and 15 replicates, each with one pair of Microarthridion littorale in copulus, were conducted for 12 d, the normal time needed for females to produce one set of nauplii and carry a second clutch of eggs. In both experiments, a significant decrease in number of nauplii was found with Aroclor contamination. Although NOECs were not determined, high concentrations of the sediment-associated Aroclor NOECs were required to affect mortality significantly, whereas lower levels impaired reproduction.

  13. The acute toxicity of fenitrothion on narrow-clawed crayfish (Astacus leptodactylus Eschscholtz, 1823) in association with biomarkers of lipid peroxidation.

    PubMed

    Sarikaya, Rabia; Sepici-Dinçel, Aylin; Caǧlan Karasu Benli, A; Selvi, Mahmut; Erkoç, Figen

    2011-01-01

    The aim of this research was to evaluate the acute toxicity of fenitrothion to the crayfish (Astacus leptodactylus Eschscholtz, 1823), which is chosen as an alternative aquatic organism to fish by using the static test system and evaluate the basic lipid peroxidation parameters for the first 24 h. Crayfish of 27.3 ± 0.56 g mean weight and 10.0 ± 0.72 cm mean length were selected for the bioassay experiments. The experiments were repeated three times in 20 liters of tap water. The temperature of water was 21 ± 1°C. The data obtained were statistically evaluated by using a computer program developed by the United States Environmental Protection Agency, based on Finney's probit analysis method and the 96-h LC(50) value for crayfish was calculated to be 15.75 μg/L. The 95% lower and upper confidence limits for the LC(50) were 9.45 to 25.01 μg/L. In addition to the acute toxicity bioassay experiments, 24-h oxidative stress parameters such as malondialdehyde (MDA) levels and ferrous oxidation assay (FOX HP [hydrogen peroxide] equivalents) were also determined. Only MDA levels of hepatopancreas decreased at 5, 10, and 20 μg/L of fenitrothion doses. We can conclude that fenitrothion is highly toxic to crayfish, a nontarget organism in the ecosystem, and the lipid peroxidation indicators can be easily used for monitoring environmental effects. PMID:20957683

  14. Environmental effects and fate of the insecticide bifenthrin in a salt-marsh mesocosm.

    PubMed

    Pennington, Paul L; Harper-Laux, Heather; Sapozhnikova, Yelena; Fulton, Michael H

    2014-10-01

    Bifenthrin is a widely used synthetic pyrethroid insecticide that is often applied to crops, turf, and residential structures for the control of insects. Like other insecticides, bifenthrin has the potential to contaminate bodies of water that are adjacent to the application site via spray drift and runoff during storm events. The objective of this study was to examine the lethal and sublethal effects of bifenthrin on grass shrimp, Palaemonetes pugio, and sheepshead minnow, Cyprinodon variegatus in a 28 d mesocosm experiment under estuarine conditions. Endpoints included mortality and growth and the oxidative stress biomarkers of lipid peroxidation, glutathione, and catalase. In the mesocosm experiment, 24 h and 96 h caged shrimp LC50s were 0.061 and 0.051 μg L(-1), respectively. The uncaged grass shrimp 28 d LC50 was 0.062 μg L(-1). Fifty percent mortality was not reached in the uncaged sheepshead minnow. Bifenthrin did not have a significant effect on the growth of the shrimp, but there was an increasing impact on fish growth. However, it is uncertain as to whether this pattern is a direct effect of the chemical or if it is due to increased food availability resulting from mortality in prey species. The oxidative stress assays were largely inconclusive. Bifenthrin was eliminated rapidly from the water column and readily partitioned to sediments. The LC50s for adult and larval P. pugio were below published Estimated Environmental Concentration (EEC) values and were within the range of bifenthrin concentrations that have been measured in rivers, channels, and creeks.

  15. The Effect of Chemical Composition and Bioactivity of Several Essential Oils on Tenebrio molitor (Coleoptera: Tenebrionidae).

    PubMed

    Wang, Xuegui; Hao, Qiang; Chen, Yiqu; Jiang, Surong; Yang, Qunfang; Li, Qing

    2015-01-01

    The major chemical components of four essential oils (EOs) extracted from dry leaves of Citrus limonum, Cymbopogon citratus, Litsea cubeba, and Muristica fragrans were analyzed with gas chromatograph-mass spectrometer and their fumigant, contact, and repellent activities against 10th instar and adults of Tenebrio molitor were also assayed. The results indicated that the major constituents of C. limonum and Cy. citrates were D-limonene (38.22%) and 3,7-dimethyl-6-octenal (26.21%), while which of L. cubeba and M. fragrans were (E)-3, 7-dimethyl-2, 6-octadienal (49.78%) and (E)-cinnamaldehyde (79.31%), respectively. Contact activities of L. cubeba and C. limonum with LC50 values of 21.2 and 13.9 µg/cm(2) at 48 h and repellence activities (>89.0% repellence indexes) (P < 0.05) at 12 h on 10th instar were better than those of the other two EOs. Nevertheless, the fumigation activities of L. cubeba on 10th instar and adults (LC50 = 2.7, 3.7 μl/liter) were stronger than those of C. limonum (LC50 = 10.9, 12.0 μl/liter) at 96 h and significant (not overlapping confidence intervals). The EOs of L. cubeba and C. limonum have clearly elongated the growth and development of larvae, egg, and slightly shorten pupae and adults of T. molitor compared with the control. The mainly active ingredients of L. cubeba and C. limonum, including D-limonene and β-pinene, were demonstrated to coinhibit the actives of AChE and enhance the toxicities on 10th instar of T. molitor. These results indicate that the EOs of L. cubeba and C. limonum could have great potential as botanical insecticides against T. molitor.

  16. The Effect of Chemical Composition and Bioactivity of Several Essential Oils on Tenebrio molitor (Coleoptera: Tenebrionidae).

    PubMed

    Wang, Xuegui; Hao, Qiang; Chen, Yiqu; Jiang, Surong; Yang, Qunfang; Li, Qing

    2015-01-01

    The major chemical components of four essential oils (EOs) extracted from dry leaves of Citrus limonum, Cymbopogon citratus, Litsea cubeba, and Muristica fragrans were analyzed with gas chromatograph-mass spectrometer and their fumigant, contact, and repellent activities against 10th instar and adults of Tenebrio molitor were also assayed. The results indicated that the major constituents of C. limonum and Cy. citrates were D-limonene (38.22%) and 3,7-dimethyl-6-octenal (26.21%), while which of L. cubeba and M. fragrans were (E)-3, 7-dimethyl-2, 6-octadienal (49.78%) and (E)-cinnamaldehyde (79.31%), respectively. Contact activities of L. cubeba and C. limonum with LC50 values of 21.2 and 13.9 µg/cm(2) at 48 h and repellence activities (>89.0% repellence indexes) (P < 0.05) at 12 h on 10th instar were better than those of the other two EOs. Nevertheless, the fumigation activities of L. cubeba on 10th instar and adults (LC50 = 2.7, 3.7 μl/liter) were stronger than those of C. limonum (LC50 = 10.9, 12.0 μl/liter) at 96 h and significant (not overlapping confidence intervals). The EOs of L. cubeba and C. limonum have clearly elongated the growth and development of larvae, egg, and slightly shorten pupae and adults of T. molitor compared with the control. The mainly active ingredients of L. cubeba and C. limonum, including D-limonene and β-pinene, were demonstrated to coinhibit the actives of AChE and enhance the toxicities on 10th instar of T. molitor. These results indicate that the EOs of L. cubeba and C. limonum could have great potential as botanical insecticides against T. molitor. PMID:26254287

  17. Acute toxicity of three fire-retardant and two fire-suppressant foam formulations to the early life stages of rainbow trout (Oncorhynchus mykiss)

    USGS Publications Warehouse

    Gaikowski, Mark P.; Hamilton, Steven J.; Buhl, Kevin J.; McDonald, Susan F.; Summers, Cliff H.; Linder, G.; Krest, S.; Sparling, D.; Little, E.

    1996-01-01

    Laboratory studies were conducted with five early life stages of rainbow trout, Oncorhynchus mykiss, to determine the acute toxicities of five fire-fighting chemical formulations in standardized soft and hard water. Eyed egg, embryo–larvae, swim-up fry, and 60- and 90-d posthatch juveniles were exposed to three fire retardants (Fire-Trol LCG-R, Fire-Trol GTS-R, and Phos-Chek D75-F) and two fire-suppressant foams (Phos-Chek WD-881 and Silv-Ex). Swim-up fry were generally the most sensitive life stage, whereas the eyed-egg was the least sensitive. Toxicity of fire-fighting formulations was greater in hard water than in soft water for all life stages tested with Fire-Trol GTS-R and Silv-Ex and for 90-d-old juveniles tested with Fire-Trol LCG-R. The fire-suppressant foams were more toxic than the fire retardants. The 96-h median lethal concentrations (LC50s) were ranked from the most toxic to the least toxic formulation as follows (ranges are the lowest and highest 96-h LC50 calculated for each formulation): Phos-Chek WD-881 (11–44 mg/L), Silv-Ex (11–78 mg/L), Phos-Chek D75-F (218–>3,600 mg/L), Fire-Trol GTS-R (207–>6,000 mg/L), and Fire-Trol LCG-R (872–>10,000 mg/L). Toxicity values suggest that accidental entry of fire-fighting chemicals into aquatic environments could adversely affect fish populations.

  18. Toxicity of oil dispersant, crude oil and dispersed crude oil to a marine amphipod and gastropod

    SciTech Connect

    Gulec, I.; Holdway, D.A.

    1995-12-31

    The importance of appropriate oil spill remedial action was emphasized during the recent Iron Barron oil spill off of the Tamar river in North Tasmania. One important potential oil spill response is dispersion, but little information exists on the toxicity of dispersants and dispersed oil to Australian marine species. This research was undertaken to assess the acute toxicity of Corexit 9527 (a widely used dispersant), water accommodated fractions of Bass Strait crude oil and dispersed Bass Strait crude oil, to the saltwater amphipod, Allorchestes compressa under semi-static conditions. Acute 96 h LC50`s were determined for each toxicant as well as for the reference toxicants sodium dodecyl sulfate (SDS) and zinc sulfate. Sublethal bioassays were undertaken for the same 3 toxicants utilizing the marines and snail Polinices conicus as the test species. No-observed-effect-concentrations (NOEC) and lowest-observed-effect-concentrations (LOEC) were determined using ANOVA while EC50`s and EC0`s were calculated using regression analysis. Mean acute 96 h LC50 (S.E.) values for A. compressa exposed to SDS and zinc sulfate were 3.6 mg/l (0.28) and 41.6 mg/l (9.01) respectively. EC50 (S.E.) concentrations for P. conicus exposed to SDS and zinc sulfate for 30 minutes were 44.7 mg/l and 246 mg/l respectively using burying behavior as an endpoint. These sublethal EC50`s were reduced to 20.7 mg/l for SDS and 23.5 mg/l for zinc sulfate following 24 hours of exposure.

  19. Relative importance of calcium and magnesium in hardness-based modification of copper toxicity

    SciTech Connect

    Welsh, P.G.; Lipton, J.; Chapman, G.A.; Podrabsky, T.L.

    2000-06-01

    Because of the relationship between water hardness and the toxicity of many metals, total hardness is used as a model parameter to calculate ambient water quality criteria for copper and other metals. However, the relative contribution of the Ca and Mg components of total hardness as modifiers of metals toxicity is not considered in the water quality criteria. Acute Cu toxicity was measured in rainbow trout (Oncorhynchus mykiss) and chinook salmon (O. tshawytscha) swim-up fry in laboratory waters that were formulated to have similar total hardness and alkalinity but different Ca and Mg concentrations. Experiments were performed at nominal total hardness values of 40 and 90 mg/L (as CaCO{sub 3}). In four paired toxicity tests, acute Cu toxicity was significantly lower, i.e., 96-h LC50s were higher, in laboratory waters containing proportionately more Ca (Ca:Mg molar ratios of 1.5--5.2) than in waters containing less Ca (Ca:Mg molar ratios of 0.2--0.8). the relative increase in the 96-h Cu LC50 at higher Ca concentrations, but similar total hardness concentrations, was between 29 and 86% when the low Ca treatment was similar to American Society for Testing and Materials laboratory water. Failure to account for differences in Ca when matching or adjusting for total hardness thus exerts an important influence on the prediction of metal toxicity. These differences must be addressed in water-effect ratio testing in which paired tests with laboratory and site waters are conducted.

  20. Toxic and genotoxic effects of Roundup on tadpoles of the Indian skittering frog (Euflictis cyanophlyctis) in the presence and absence of predator stress.

    PubMed

    Yadav, Sushama Singh; Giri, Sarbani; Singha, Utsab; Boro, Freeman; Giri, Anirudha

    2013-05-15

    Glyphosate, a post emergent herbicide, has become the backbone of no-till agriculture and is considered safe for animals. However, the impact of glyphosate on non-target organisms, especially on amphibians, is the subject of major concern and debate in recent times. We examined the toxic and genotoxic effects of Roundup, a commercial formulation of glyphosate, in the tadpoles of the Indian skittering frog (Euflictis cyanophlyctis). Roundup at different concentrations (0, 1, 2, 3, 4 and 8mg acid equivalent (ae)/L), tested in a 2×6 factorial design in the presence and absence of predator stress, induced concentration-dependent lethality in tadpoles. The 96-h LC50 for Roundup in the absence and presence of predator stress were 3.76mgae/L and 3.39mgae/L, respectively. The 10-day LC50 value for Roundup was significantly lower, 2.12mgae/L and 1.91mgae/L in the absence and presence of predator stress, respectively. Lower concentrations of Roundup (1, 2 and 3mgae/L) induced the formation of micronuclei (MN) in the erythrocytes of tadpoles at 24-h (F3,56=10.286, p<0.001), 48-h (F3,56=48.255, p<0.001), 72-h (F3,56=118.933, p<0.001) and 96-h (F3,56=85.414, p<0.001) in a concentration-dependent manner. Presence of predator stress apparently increased the toxicity and genotoxicity of Roundup; but these effects were not statistically significant. These findings suggest that Roundup at environmentally relevant concentrations has lethal and genotoxic impact on E. cyanophlyctis; which may have long-term fitness consequence to the species.

  1. The Value of Reciprocity

    ERIC Educational Resources Information Center

    Molm, Linda D.; Schaefer, David R.; Collett, Jessica L.

    2007-01-01

    The value of reciprocity in social exchange potentially comprises both instrumental value (the value of the actual benefits received from exchange) and communicative or symbolic value (the expressive and uncertainty reduction value conveyed by features of the act of reciprocity itself). While all forms of exchange provide instrumental value, we…

  2. Acute and chronic toxicity of selected disinfection byproducts to Daphnia magna, Cyprinodon variegatus, and Isochrysis galbana.

    PubMed

    Fisher, Daniel; Yonkos, Lance; Ziegler, Gregory; Friedel, Elizabeth; Burton, Dennis

    2014-05-15

    Ballast water treatment has become a major issue in the last decade due to the problem of invasive species transported and released by the uptake and discharge of ballast water for shipping operations. One of the important issues considering ballast water treatment is to determine whether treated ballast water, once discharged, is safe to the aquatic environment. The International Maritime Organization (IMO) Marine Environmental Protection Committee (MEPC) has determined that prior to approval of a ballast water management system, aquatic toxicity data must be available for both the active substance and relevant byproducts. Many proposed ballast water treatment systems use chlorine as the active ingredient. Although there are sufficient toxicity data concerning active substances such as chlorine, there are limited toxicity data concerning disinfection (halogenated) byproducts including dibromochloromethane, four haloacetic acids and sodium bromate. Acute and chronic toxicity were determined for these disinfection byproducts (DBPs). Acute toxicity values ranged from 96-h LC50s of 46.8 mg/l for Daphnia magna for both dibromochloromethane and sodium bromate to a 96-h LC50 of 376.4 mg/l for Cyprinodon variegatus for tribromoacetic acid. Acute Isochrysis galbana population growth effect values ranged from a 72-h EC10 of 39.9 mg/l for dichloroacetic acid to a 72-h EC50 of 15,954 mg/l for sodium bromate. Chronic toxicity mortality/reproduction effects values for D. magna ranged from a 21-d IC25 of 160.9 mg/l for tribromoacetic acid to a 21-d LOEC of 493.0 mg/l for trichloroacetic acid. Chronic toxicity mortality/growth values for C. variegatus ranged from a 32-d IC25 of 246.8 mg/l for trichloroacetic acid to a 32-d LOEC of 908.1 mg/l for tribromoacetic acid. I. galbana 96-h chronic population growth effects values ranged from an EC10 of 38.5 mg/l for trichloroacetic acid to an LOEC of 500.0 mg/l for tribromoacetic acid. Acute to chronic ratios for all of these

  3. Maslow and Values Education

    ERIC Educational Resources Information Center

    Farmer, Rodney

    1978-01-01

    Identifies major value bases which have been used to teach values in the classroom and outlines a values education program which stresses teaching about values without indoctrination. Based upon the hierarchy of human needs developed by psychologist Abraham Maslow, the program is based upon universal values, basic human needs, and recognition of…

  4. Integrated assessment of biochemical markers in premetamorphic tadpoles of three amphibian species exposed to glyphosate- and methidathion-based pesticides in single and combination forms.

    PubMed

    Güngördü, Abbas; Uçkun, Miraç; Yoloğlu, Ertan

    2016-02-01

    In this study, we evaluated the toxic effects of a glyphosate-based herbicide (GBH) and a methidathion-based insecticide (MBI), individually and in combination, on premetamorphic tadpoles of three anuran species: Pelophylax ridibundus, Xenopus laevis, and Bufotes viridis. Based on the determined 96-h LC50 values of each species, the effects of a series of sublethal concentrations of single pesticides and their mixtures after 96-h exposure and also the time-related effects of a high sublethal concentration of each pesticide were evaluated, with determination of changes in selected biomarkers: glutathione S-transferase (GST), glutathione reductase (GR), acetylcholinesterase (AChE), carboxylesterase (CaE), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Also, the integrated biomarker response (IBR) was used to assess biomarker responses and quantitatively evaluate toxicological effects. Isozyme differences in CaE inhibition were assessed using native page electrophoresis; results showed that GBH to cause structural changes in the enzyme but not CaE inhibition in P. ridibundus. In general, single MBI and pesticide mixture exposures increased GST activity, while single GBH exposures decreased GST activity in exposed tadpoles. The AChE and CaE activities were inhibited after exposure to all single MBI and pesticide mixtures. Also, higher IBR values and GST, GR, AST, and LDH activities were determined for pesticide mixtures compared with single-pesticide exposure. This situation may be indicative of a synergistic interaction between pesticides and a sign of a more stressful condition. PMID:26595308

  5. Toxicity of botanical formulations to nursery-infesting white grubs (Coleoptera: Scarabaeidae).

    PubMed

    Ranger, Christopher M; Reding, Michael E; Oliver, Jason B; Moyseenko, James J; Youssef, Nadeer N

    2009-02-01

    The toxicity of eight botanically based biopesticides was evaluated against third instars of the scarab larvae (Coleoptera: Scarabaeidae) Popillia japonica Newman, Rhizotrogus majalis (Razoumowsky), Anomala orientalis Waterhouse, and Cyclocephala borealis Arrow. Soil dip bioassays were used to obtain concentration-mortality data 7 d after treatment of larvae, leading to the calculation of LC50 and LC90 values. A wide range in LC50 and LC90 values were exhibited among the formulations. The product Armorex was one of the most active formulations against P. japonica (LC50 = 0.42 ml/liter), R. majalis (LC50 = 0.48 ml/liter), A. orientalis (LC50 = 0.39 ml/liter), and C. borealis (LC50 = 0.49 ml/liter). Armorex is composed of extracts from diverse botanical sources, including 84.5% sesame oil, 2.0% garlic oil, 2.0% clove oil, 1.0% rosemary oil, and 0.5% white pepper extracts. The product Azatin, composed of 3% azadirachtin, also exhibited high toxicity to P. japonica (LC50 = 1.13 ml/liter), R. majalis (LC50 = 0.81 ml/liter), and A. orientalis (LC50 = 1.87 ml/liter). Veggie Pharm is composed of extracts from diverse sources, but this product showed the lowest toxicity to P. japonica (LC50 = 35.19 ml/liter), R. majalis (LC50 = 62.10 ml/liter), A. orientalis (LC50 = 43.76 ml/liter), and C. borealis (LC50 = 50.24 ml/liter). These results document the potential for botanical formulations to control white grubs, but blending extracts from diverse botanical sources does not ensure enhanced biological activity. PMID:19253649

  6. Exposure to fenvalerate causes brain impairment during zebrafish development.

    PubMed

    Gu, Aihua; Shi, Xiangguo; Yuan, Chen; Ji, Guixiang; Zhou, Yong; Long, Yan; Song, Ling; Wang, Shoulin; Wang, Xinru

    2010-09-01

    Compared with increasing evidence suggesting that fenvalerate is neurotoxic to adults, further information regarding developmental toxicity of this compound attracts more attention. In this study, we used zebrafish as an environmental monitoring model to further explore the potential toxicity of fenvalerate. Our results demonstrated that larvae exposed to fenvalerate for 24-96 h displayed obvious morphological abnormalities, and the LC50 concentrations were 131.95 microg/L (LC50-24h), 107.18 microg/L (LC50-48 h), 21.76 microg/L (LC50-72 h), and 6.25 microg/L (LC50-96 h). To further investigate the effects of fenvalerate on embryos and larvae, acridine orange staining was performed at a 50 microg/L concentration. Staining showed notable signs of apoptosis mainly in the brain. Further studies revealed that fenvalerate induced alterations in SOD activity in larvae were concentration dependent and also related to the length of exposure. Fenvalerate also down-regulated the expression of ogg1 and dlx2 genes in a concentration dependent manner, which indicated that the oxidative-DNA repair system as well as neurogenesis were impaired. In this study, we investigated the toxicity of fenvalerate using zebrafish, that provided new evidence of observable brain impairment during embryogenesis due to fenvalerate exposure and discussed their implications for the development of fenvalerate induced neurotoxicity.

  7. Agricultural Education: Value Adding.

    ERIC Educational Resources Information Center

    Riesenberg, Lou E.; And Others

    1989-01-01

    This issue develops the theme of "Agricultural Education--Value Adding." The concept value adding has been a staple in the world of agricultural business for describing adding value to a commodity that would profit the producer and the local community. Agricultural education should add value to individuals and society to justify agricultural…

  8. Teaching Absolute Value Meaningfully

    ERIC Educational Resources Information Center

    Wade, Angela

    2012-01-01

    What is the meaning of absolute value? And why do teachers teach students how to solve absolute value equations? Absolute value is a concept introduced in first-year algebra and then reinforced in later courses. Various authors have suggested instructional methods for teaching absolute value to high school students (Wei 2005; Stallings-Roberts…

  9. On Literature and Values.

    ERIC Educational Resources Information Center

    Beach, Richard

    In reviewing the ancient, well-worn debate on the relationship between literature and values, it may be seen that the current pedagogical theory of developing response to literature is parallel to the argument for helping students articulate their own values. Two approaches to clarifying values are the values clarification approach (Louis Raths,…

  10. Five Values of Giftedness

    ERIC Educational Resources Information Center

    Besjes-de Bock, Karin M.; de Ruyter, Doret J.

    2011-01-01

    This article describes five values attributed to giftedness. The ascription of values to this phenomenon resembles values attached to gifts in gift-giving processes. Whereas gift-giving often includes expectations of reciprocity, each gift possesses a numerical, utility, social, personal, and intrinsic value. Developmental models of giftedness and…

  11. Brine shrimp toxicity of some plants used as traditional medicines in Kagera Region, north western Tanzania.

    PubMed

    Moshi, M J; Innocent, E; Magadula, J J; Otieno, D F; Weisheit, A; Mbabazi, P K; Nondo, R S O

    2010-01-01

    Dichloromethane and/or ethanol extracts of 30 plants used as traditional medicines in Bukoba district, northwestern Tanzania were evaluated for brine shrimp toxicity. Among the 50 extracts tested, 32 extracts (64%) showed very low toxicity with LC50 values above 100 microg/ml. Among these 12 (24%) which had LC50 >500 microg/ml can be categorized as being practically non-toxic. Among the remaining extracts 19 (38%) which showed LC50 > 100 < 500 microg/ml are also considered to be non-toxic. Extracts that showed LC50 results between 30-100 microg/ml have been categorized as mildly toxic; these include ethanol extracts of Lantana trifolia (LC50 32.3 microg/ml), Vernonia bradycalyx (LC50 33.9 microg/ml), Antiaris toxicaria (LC50 38.2 microg/ml) and Rubus rigidus (LC50 41.7 microg/ml) and the dichloromethane extracts of Gynura scandens (LC50 36.5 microg/ml) and Bridelia micrantha (LC50 32.0 microg/ml). The dichloromethane extracts of Picralima nitida (LC50 18.3 microg/ml) and Rubus rigidus (LC50 19.8 microg/ml), were only moderately toxic. Picralima nitida and Rubus rigidus extracts are only 1.1 and 1.2 less toxic than the standard drug, cyclophosphamide (LC50 16.3 microg/ml). In conclusion, the results indicate that among the 30 plants used as traditional medicines, 28 are safe for short term use. Picralima nitida and Rubus rigidus extracts are mildly toxic, but by comparison have a remote possibility to yield active anticancer compounds.

  12. Concentrations, transport and biological effects of dormant spray pesticides in the San Francisco Estuary, California

    USGS Publications Warehouse

    Kuivila, K.M.; Foe, C.G.

    1995-01-01

    The transport and biological effects of dormant spray pesticides were examined in the San Francisco Estuary, California, by measuring dissolved- pesticide concentrations and estimating toxicity using bioassays at a series of sites in January and February 1993. Distinct pulses of pesticides, including diazinon, methidathion, and chlorpyrifos, were detected in the San Joaquin River in January and February and in the Sacramento River in February following rainfall. The higher pesticide loads in the Sacramento River compared with those in the San Joaquin River can be attributed to the greater amount of rainfall in the Sacramento Valley. The use patterns and water solubility of the pesticides can account for the observed temporal and spatial distributions in the two rivers. The pesticide pulses detected at Sacramento were followed through the northern embayment of San Francisco Estuary. In contrast, the pesticide distribution in the Sacramento-San Joaquin Delta changed from distinct pulses to steady increases in concentration over time. Seven-day bioassays indicated that Sacramento River water at Rio Vista was acutely toxic to Ceriodaphnia dubia (water flea) for 3 consecutive d and San Joaquin River water at Vernalis for 12 consecutive d. These water samples all had the highest diazinon concentrations. Examination of 96-h LC50 values (lethal concentration that kills 50% of test organisms in 96 H) indicates that measured diazinon concentrations could account for most but not all the observed toxicity. Other pesticides present could contribute to the toxicity.

  13. Effects of the synthetic pyrethroid insecticide, permethrin, on two estuarine fish species.

    PubMed

    Parent, Lindsey M; Delorenzo, Marie E; Fulton, Michael H

    2011-01-01

    Limited toxicity data are available for estuarine and marine species and the widely used pyrethroid insecticide, permethrin. This study determined acute effects of permethrin on survival, lipid peroxidation, acetylcholinesterase activity, and splenocyte proliferation for two fish species found in South Carolina estuaries; juvenile red drum (Sciaenops ocellatus) and adult mummichog (Fundulus heteroclitus). Juvenile S. ocellatus were significantly more sensitive than adult F. heteroclitus to permethrin exposure, with a 96-h LC50 value of 8 μg/L determined for red drum compared to 23 μg/L for mummichog. Lipid peroxidation activity of the liver increased in permethrin-treated fish compared to control animals after 24 h and decreased after 96 h. Permethrin had no effect on acetylcholinesterase activity of the brain at the concentrations tested. Permethrin exposure significantly inhibited splenocyte proliferation, indicating an immunosuppressive effect. Most of the effects of permethrin on fish cellular stress enzymes and survival occurred at concentrations much higher than those typically measured in the environment. However, inhibition of splenocyte proliferation in juvenile red drum occurred at approximately twice that of measured permethrin concentrations in surface water. These findings may prove useful to the future management and regulation of pyrethroid insecticide use near estuarine habitats. PMID:21756140

  14. Effects of pyrethroid insecticides in urban runoff on Chinook salmon, steelhead trout, and their invertebrate prey.

    PubMed

    Weston, Donald P; Schlenk, Daniel; Riar, Navneet; Lydy, Michael J; Brooks, Marjorie L

    2015-03-01

    Pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or directly by toxicity to the fish themselves. In support of a study on pyrethroid impacts to Chinook salmon and steelhead trout in the American River (Sacramento, California, USA), 96-h median effective concentration (EC50) and median lethal concentration (LC50) values for the pyrethroid bifenthrin were determined for taxa not traditionally used for toxicity testing but of interest as salmonid prey, including a chironomid, caddisflies, mayflies, and stoneflies. A laboratory was constructed on the banks of the American River to expose macroinvertebrates, Chinook salmon, and steelhead trout to flow-through river water containing urban runoff during storm events. Bifenthrin from urban runoff was found in river water following 5 rain events, reaching 14.6 ng/L. Mortality to the exposed salmonids was not observed, and sublethal effects were not seen in vitellogenin or sex steroid levels. Indirect effects via toxicity to salmonid prey are possible. Mortality to Hyalella azteca, a potential prey, was observed in every event tested, and peak bifenthrin concentrations were comparable to the 96-h EC50 of the caddisfly, Hydropsyche sp., the most important prey species on a biomass basis for American River Chinook salmon. The other invertebrates tested had EC50s exceeding bifenthrin concentrations seen in the American River, though could potentially be at risk at concentrations previously reported in smaller urban tributaries. Environ Toxicol Chem 2015;34:649-657. © 2014 SETAC. PMID:25545717

  15. The influence of etofenprox on narrow clawed crayfish (Astacus leptodactylus Eschscholtz, 1823): Acute toxicity and sublethal effects on histology, hemolymph parameters, and total hemocyte counts.

    PubMed

    Benli, Aysel Caglan Karasu

    2015-07-01

    The acute and sublethal effects of etofenprox, a nonester pyrethroid, was determined in narrow-clawed crayfish (Astacus leptodactylus Eschscholtz, 1823). Semistatic bioassay procedures were followed in both experiments, and the 24, 48, 72, and 96 h LC50 values (with 95% confidence limits) of technical etofenprox for crayfish were calculated as 0.68, 0.61, 0.45, and 0.41 µg/L, respectively based on Finney's probit analysis. Two concentrations of etofenprox (0.04 and 0.1 µg/L) were tested to determine sublethal effects due to 96 hours exposure. After exposure to sublethal etofenprox, hemolymph glucose, and lactate levels increased while total hemocyte counts and sodium levels decreased (p < 0.05). Hemolymph calcium, potassium, magnesium, and chloride concentrations did not change significantly. Histological alterations were evident in the gills and hepatopancreas after exposure to sublethal etofenprox concentrations. Lamellar hyperplasia and lining in the afferent and efferent branchial vessels were recorded in gills; whilst tubule necrosis was obvious in hepatopancreas. Etofenprox was found to be very highly toxic to crayfish, a nontarget organism. Exposure to sublethal concentrations for 96 h affected circulating hemocytes and hemolymph stress parameters via histological response, to compansate for the adverse effects of etofenprox. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 887-894, 2015.

  16. Effects of the synthetic pyrethroid insecticide, permethrin, on two estuarine fish species.

    PubMed

    Parent, Lindsey M; Delorenzo, Marie E; Fulton, Michael H

    2011-01-01

    Limited toxicity data are available for estuarine and marine species and the widely used pyrethroid insecticide, permethrin. This study determined acute effects of permethrin on survival, lipid peroxidation, acetylcholinesterase activity, and splenocyte proliferation for two fish species found in South Carolina estuaries; juvenile red drum (Sciaenops ocellatus) and adult mummichog (Fundulus heteroclitus). Juvenile S. ocellatus were significantly more sensitive than adult F. heteroclitus to permethrin exposure, with a 96-h LC50 value of 8 μg/L determined for red drum compared to 23 μg/L for mummichog. Lipid peroxidation activity of the liver increased in permethrin-treated fish compared to control animals after 24 h and decreased after 96 h. Permethrin had no effect on acetylcholinesterase activity of the brain at the concentrations tested. Permethrin exposure significantly inhibited splenocyte proliferation, indicating an immunosuppressive effect. Most of the effects of permethrin on fish cellular stress enzymes and survival occurred at concentrations much higher than those typically measured in the environment. However, inhibition of splenocyte proliferation in juvenile red drum occurred at approximately twice that of measured permethrin concentrations in surface water. These findings may prove useful to the future management and regulation of pyrethroid insecticide use near estuarine habitats.

  17. OECD validation study to assess intra- and inter-laboratory reproducibility of the zebrafish embryo toxicity test for acute aquatic toxicity testing.

    PubMed

    Busquet, François; Strecker, Ruben; Rawlings, Jane M; Belanger, Scott E; Braunbeck, Thomas; Carr, Gregory J; Cenijn, Peter; Fochtman, Przemyslaw; Gourmelon, Anne; Hübler, Nicole; Kleensang, André; Knöbel, Melanie; Kussatz, Carola; Legler, Juliette; Lillicrap, Adam; Martínez-Jerónimo, Fernando; Polleichtner, Christian; Rzodeczko, Helena; Salinas, Edward; Schneider, Katharina E; Scholz, Stefan; van den Brandhof, Evert-Jan; van der Ven, Leo T M; Walter-Rohde, Susanne; Weigt, Stefan; Witters, Hilda; Halder, Marlies

    2014-08-01

    The OECD validation study of the zebrafish embryo acute toxicity test (ZFET) for acute aquatic toxicity testing evaluated the ZFET reproducibility by testing 20 chemicals at 5 different concentrations in 3 independent runs in at least 3 laboratories. Stock solutions and test concentrations were analytically confirmed for 11 chemicals. Newly fertilised zebrafish eggs (20/concentration and control) were exposed for 96h to chemicals. Four apical endpoints were recorded daily as indicators of acute lethality: coagulation of the embryo, lack of somite formation, non-detachment of the tail bud from the yolk sac and lack of heartbeat. Results (LC50 values for 48/96h exposure) show that the ZFET is a robust method with a good intra- and inter-laboratory reproducibility (CV<30%) for most chemicals and laboratories. The reproducibility was lower (CV>30%) for some very toxic or volatile chemicals, and chemicals tested close to their limit of solubility. The ZFET is now available as OECD Test Guideline 236. Considering the high predictive capacity of the ZFET demonstrated by Belanger et al. (2013) in their retrospective analysis of acute fish toxicity and fish embryo acute toxicity data, the ZFET is ready to be considered for acute fish toxicity for regulatory purposes.

  18. Nitrite toxicity to the crayfish Procambarus clarkii

    SciTech Connect

    Gutzmer, M.P.; Tomasso, J.R.

    1985-03-01

    The purpose of this study was to determine the effects of acute nitrite exposure to the crayfish Procambarus clarkii (Decapoda). Specific objectives of this study included (1) determining the 24-, 48-, 72- and 96-h LC-50's of nitrite to crayfish of different weights and genders in freshwater, (2) determining the LC-50's of nitrite to crayfish in water with elevated chloride concentrations, and (3), in order to gain insight into the mechanisms of nitrite toxicity in crayfish, determining hemolymph nitrite concentrations in crayfish exposed to nitrite in freshwater and water with elevated chloride concentrations.

  19. Exploring Existence Value

    NASA Astrophysics Data System (ADS)

    Madariaga, Bruce; McConnell, Kenneth E.

    1987-05-01

    The notion that individuals value the preservation of water resources independent of their own use of these resources is discussed. Issues in defining this value, termed "existence value," are explored. Economic models are employed to assess the role of existence value in benefit-cost analysis. The motives underlying existence value are shown to matter to contingent valuation measurement of existence benefits. A stylized contingent valuation experiment is used to study nonusers' attitudes regarding projects to improve water quality in the Chesapeake Bay. Survey results indicate that altruism is one of the motives underlying existence value and that goods other than environmental and natural resources may provide existence benefits.

  20. Comparative toxicity of sodium carbonate peroxyhydrate to freshwater organisms.

    PubMed

    Geer, Tyler D; Kinley, Ciera M; Iwinski, Kyla J; Calomeni, Alyssa J; Rodgers, John H

    2016-10-01

    Sodium carbonate peroxyhydrate (SCP) is a granular algaecide containing H2O2 as an active ingredient to control growth of noxious algae. Measurements of sensitivities of target and non-target species to hydrogen peroxide are necessary for water resource managers to make informed decisions and minimize risks for non-target species when treating noxious algae. The objective of this study was to measure and compare responses among a target noxious alga (cyanobacterium Microcystis aeruginosa) and non-target organisms including a eukaryotic alga (chlorophyte Pseudokirchneriella subcapitata), microcrustacean (Ceriodaphnia dubia), benthic amphipod (Hyalella azteca), and fathead minnow (Pimephales promelas) to exposures of hydrogen peroxide as SCP. Hydrogen peroxide exposures were confirmed using the I3(-) method. SCP margins of safety for these organisms were compared with published toxicity data to provide context for other commonly used algaecides and herbicides (e.g. copper formulations, endothall, and diquat dibromide). Algal responses (cell density and chlorophyll a concentrations) and animal mortality were measured after 96h aqueous exposures to SCP in laboratory-formulated water to estimate EC50 and LC50 values, as well as potency slopes. Despite a shorter test duration, M. aeruginosa was more sensitive to hydrogen peroxide as SCP (96h EC50:0.9-1.0mgL(-)(1) H2O2) than the eukaryotic alga P. subcapitata (7-d EC50:5.2-9.2mgL(-1) H2O2), indicating potential for selective control of prokaryotic algae. For the three non-target animals evaluated, measured 96-h LC50 values ranged from 1.0 to 19.7mgL(-1) H2O2. C. dubia was the most sensitive species, and the least sensitive species was P. promelas, which is not likely to be affected by concentrations of hydrogen peroxide as SCP that would be used to control noxious algae (e.g. M. aeruginosa). Based on information from peer-reviewed literature, other algaecides could be similarly selective for cyanobacteria. Of the

  1. Comparative toxicity of sodium carbonate peroxyhydrate to freshwater organisms.

    PubMed

    Geer, Tyler D; Kinley, Ciera M; Iwinski, Kyla J; Calomeni, Alyssa J; Rodgers, John H

    2016-10-01

    Sodium carbonate peroxyhydrate (SCP) is a granular algaecide containing H2O2 as an active ingredient to control growth of noxious algae. Measurements of sensitivities of target and non-target species to hydrogen peroxide are necessary for water resource managers to make informed decisions and minimize risks for non-target species when treating noxious algae. The objective of this study was to measure and compare responses among a target noxious alga (cyanobacterium Microcystis aeruginosa) and non-target organisms including a eukaryotic alga (chlorophyte Pseudokirchneriella subcapitata), microcrustacean (Ceriodaphnia dubia), benthic amphipod (Hyalella azteca), and fathead minnow (Pimephales promelas) to exposures of hydrogen peroxide as SCP. Hydrogen peroxide exposures were confirmed using the I3(-) method. SCP margins of safety for these organisms were compared with published toxicity data to provide context for other commonly used algaecides and herbicides (e.g. copper formulations, endothall, and diquat dibromide). Algal responses (cell density and chlorophyll a concentrations) and animal mortality were measured after 96h aqueous exposures to SCP in laboratory-formulated water to estimate EC50 and LC50 values, as well as potency slopes. Despite a shorter test duration, M. aeruginosa was more sensitive to hydrogen peroxide as SCP (96h EC50:0.9-1.0mgL(-)(1) H2O2) than the eukaryotic alga P. subcapitata (7-d EC50:5.2-9.2mgL(-1) H2O2), indicating potential for selective control of prokaryotic algae. For the three non-target animals evaluated, measured 96-h LC50 values ranged from 1.0 to 19.7mgL(-1) H2O2. C. dubia was the most sensitive species, and the least sensitive species was P. promelas, which is not likely to be affected by concentrations of hydrogen peroxide as SCP that would be used to control noxious algae (e.g. M. aeruginosa). Based on information from peer-reviewed literature, other algaecides could be similarly selective for cyanobacteria. Of the

  2. Share Your Values

    MedlinePlus

    ... Español Text Size Email Print Share Share Your Values Page Content Article Body Today, teenagers are bombarded ... mid-twenties. The Most Effective Way to Instill Values? By Example Your words will carry more weight ...

  3. Effect of carbon monoxide on Swiss albino mice

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Cumming, H. J.

    1977-01-01

    Times to incapacitation and death and LC50 values were determined for male Swiss albino mice exposed to different concentrations of carbon monoxide in a 4.2 liter hemispherical chamber. These values are compared to values reported in the literature. The LC50 for a 30 minute exposure was 3570 ppm CO.

  4. The Dubious Value of Value Neutrality

    ERIC Educational Resources Information Center

    Balch, Stephen H.

    2006-01-01

    Hard science is properly value neutral. But when that ideological neutrality extends to the whole university, the traditional foundation crumbles. Steve Balch laments the moral vacuum that now substitutes for fundamental principles, because it is impossible to frame a program of education--especially in the humanities and social sciences--without…

  5. The values of life.

    PubMed

    Den Hartogh, Govert

    1997-01-01

    In Life's Dominion Dworkin aims at defusing the controversy about abortion and euthanasia by redefining its terms. Basically it is not a dispute about the right to life, but about its value. Liberals should grant that human life has not only a personal, but also an intrinsic value; conservatives should accept the principle of toleration which requires to let people decide for themselves about matters of intrinsic value. Dworkin fails, however, to distinguish between two kinds of personal value: (1) the value of something to a person, when he actually or dispositionally desires it, or finds it pleasant; and (2) the value of something to a person, when it's objectively contributes to his well-being, as defined by reference to his personal point of view, whether or not he ever perceives it as so contributing. He also fails to distinguish between two meanings of the concept of 'intrinsic value': (3) ultimate, i.e. non-instrumental personal value of kind (2); (4) the impersonal value of something which is not good-for-anybody, but simply good, i.e. not a constituent of someone's well-being. Dworkin argues that the human fetus from conception onwards has a value, that it is not a personal value of kind (1), and therefore must be an intrinsic value. But the value of the life of the fetus is not a personal value of kind (2) either and therefore not an intrinsic value of kind (3): it is normally a constituent of the well-being of the pregnant woman, but that doesn't constitute its value, and it is not good 'for' the fetus itself in the relevant sense, because it doesn't have a personal point of view. If, however, the fetus' life is allowed to have an intrinsic value of kind (4), the conservative cannot be refuted by appeal to the principle of toleration, for this only concerns intrinsic value of kind (3). The liberal, indeed, should recognize that the fetus' life has a value, but it is neither a personal value (1) or (2), nor an impersonal value (4), but rather a relational

  6. Hospital perceived value.

    PubMed

    Moliner, Miguel A

    2006-01-01

    The creation, distribution and communication of value have been considered to be the key element of marketing (American Marketing Association, 2004, www.marketingpower.com). The aim of this article is to identify the indicators of perceived value in a hospital context. The results show that perceived quality and emotions are key dimensions of perceived value.

  7. Values Drive the Plan

    ERIC Educational Resources Information Center

    Cook, Les P.

    2010-01-01

    Values-integrated strategic planning provides the opportunity to clarify professional values as one envisions a future that is exciting and perhaps a bit provocative. This chapter explores the role and importance of student affairs and institutional values in strategic planning. It also looks at the historical roots of the profession and methods…

  8. Hierarchical Classification of Values

    ERIC Educational Resources Information Center

    Ergen, Gürkan

    2015-01-01

    Values are of utmost importance for the creation, development and sustainability of a life worthy of human dignity. However, because even superficial views of values are regarded as values themselves, they have become relative and become degenerated; therefore, they have lost the properties--potentials and powers--essential to human dignity. This…

  9. Hospital perceived value.

    PubMed

    Moliner, Miguel A

    2006-01-01

    The creation, distribution and communication of value have been considered to be the key element of marketing (American Marketing Association, 2004, www.marketingpower.com). The aim of this article is to identify the indicators of perceived value in a hospital context. The results show that perceived quality and emotions are key dimensions of perceived value. PMID:17077707

  10. Values: Language Arts.

    ERIC Educational Resources Information Center

    Hargraves, Richard B.

    The Quinmester course "Values" includes nine areas of study designed to develop student awareness and development of a personal value system: (1) consideration of a positive self-image as part of a system of values; (2) differentiation between acts of tolerance and intolerance; (3) investigation of the role mental preparedness based on positive…

  11. Information Economics: Valuing Information.

    ERIC Educational Resources Information Center

    Brinberg, Herbert R.

    1989-01-01

    Addresses the question of why previous articles and studies on the value of information have failed to provide meaningful techniques for measuring that value. The discussion covers four principle causes for confusion surrounding the valuation of information and draws conclusions about the value added model of information. (seven references) (CLB)

  12. Values in Further Education.

    ERIC Educational Resources Information Center

    Halliday, John, Ed.

    This book explores educational values in the British further education system. Following an introductory discussion of educational values by the editor, John Halliday, the book contains 21 short essays organized in the areas of cultural values, curriculum, and management and staff development. The following are included: "Democratic…

  13. Emergy and Nonmarket Value

    EPA Science Inventory

    The purpose of this study is to better understand the differences and similarities between emergy and nonmarket economic valuation, when both are applied to value the same policies or development alternatives. The emdollar value of a good or service often exceeds the market value...

  14. Measuring Teacher Value Systems.

    ERIC Educational Resources Information Center

    Ames, Russell; Lied, Terry

    The purpose of this study was to develop and assess the psychometric properties of a measure of teacher value systems. Three value systems were defined as values associated with (1) the pursuit of truth, (2) social and interpersonal relations, and (3) authority and its exercise. The scale was taken through three stages of development and field…

  15. Comparative study of the assay of Artemia salina L. and the estimate of the medium lethal dose (LD50 value) in mice, to determine oral acute toxicity of plant extracts.

    PubMed

    Logarto Parra, A; Silva Yhebra, R; Guerra Sardiñas, I; Iglesias Buela, L

    2001-09-01

    Artemia salina L. (Artemiidae), the brine shrimp larva, is an invertebrate used in the alternative test to determine toxicity of chemical and natural products. In this study the Medium Lethal Concentrations (LC50 value) of 20 plant extracts, Aloe vera (L.) Burm. F. (Aloeaceae), Artemisia absinthium L. (Asteraceae); Citrus aurantium L. (Rutaceae); Cymbopogon citratus (DC. Ex Nees) Stapf (Poaceae); Datura stramonium L. (Solanaceae); Justicia pectoralis Jacq. (Acanthaceae); Musa x paradisiaca L. (Musaceae); Ocimum basilicum L.; O. gratissimum L.; O. tenuiflorum L. (Lamiaceae); Pimenta dioica (L.) Merr. (Myrtaceae); Piper auritum Kunth (Piperaceae); Plantago major L. (Plantaginaceae); Plectranthus amboinicus (Lour.) Spreng. (Lamiaceae); Ruta graveolens L. (Rutaceae); Senna alata (L.) Roxb. (Fabaceae); Stachytarpheta jamaicensis (L.) Vahl (Verbenaceae); and Thuja occidentalis L. (Cupressaceae), were determined using Artemia salina L. (Artemiidae), with the objective of relating the results to the LD50 values reported in mice (tested at three concentrations: 10, 100, and 1000 microg/mL, for each extract). We found good correlation between the in vivo and the in vitro tests (r = 0.85 p < 0.05), and this method is a useful tool for predicting oral acute toxicity in plant extracts. PMID:11695884

  16. Comparative study of the assay of Artemia salina L. and the estimate of the medium lethal dose (LD50 value) in mice, to determine oral acute toxicity of plant extracts.

    PubMed

    Logarto Parra, A; Silva Yhebra, R; Guerra Sardiñas, I; Iglesias Buela, L

    2001-09-01

    Artemia salina L. (Artemiidae), the brine shrimp larva, is an invertebrate used in the alternative test to determine toxicity of chemical and natural products. In this study the Medium Lethal Concentrations (LC50 value) of 20 plant extracts, Aloe vera (L.) Burm. F. (Aloeaceae), Artemisia absinthium L. (Asteraceae); Citrus aurantium L. (Rutaceae); Cymbopogon citratus (DC. Ex Nees) Stapf (Poaceae); Datura stramonium L. (Solanaceae); Justicia pectoralis Jacq. (Acanthaceae); Musa x paradisiaca L. (Musaceae); Ocimum basilicum L.; O. gratissimum L.; O. tenuiflorum L. (Lamiaceae); Pimenta dioica (L.) Merr. (Myrtaceae); Piper auritum Kunth (Piperaceae); Plantago major L. (Plantaginaceae); Plectranthus amboinicus (Lour.) Spreng. (Lamiaceae); Ruta graveolens L. (Rutaceae); Senna alata (L.) Roxb. (Fabaceae); Stachytarpheta jamaicensis (L.) Vahl (Verbenaceae); and Thuja occidentalis L. (Cupressaceae), were determined using Artemia salina L. (Artemiidae), with the objective of relating the results to the LD50 values reported in mice (tested at three concentrations: 10, 100, and 1000 microg/mL, for each extract). We found good correlation between the in vivo and the in vitro tests (r = 0.85 p < 0.05), and this method is a useful tool for predicting oral acute toxicity in plant extracts.

  17. Evaluation of the combined effect of thymol, carvacrol and (E)-cinnamaldehyde on Amblyomma sculptum (Acari: Ixodidae) and Dermacentor nitens (Acari: Ixodidae) larvae.

    PubMed

    Novato, Tatiane Pinheiro Lopes; Araújo, Laryssa Xavier; de Monteiro, Caio Márcio Oliveira; Maturano, Ralph; Senra, Tatiane de Oliveira Souza; da Silva Matos, Renata; Gomes, Geovany Amorim; de Carvalho, Mario Geraldo; Daemon, Erik

    2015-09-15

    This study aimed at assessing the combined effect of thymol, carvacrol and (E)-cinnamaldehyde on Amblyomma sculptum and Dermacentor nitens larvae. The effects resulting from treatments were evaluated by means of the modified larval packet test. In order to determine the LC50, components of essential oils, the monoterpenes thymol, carvacrol and phenylpropanoid (E)-cinnamaldehyde were individually tested at different concentrations. After determining the LC50, each essential oil component was separately evaluated and then combined with another substance at a 1:1 proportion at the LC50 concentration and at 1/2 and 1/4 of the LC50. For A. sculptum, the lowest LC50 value was obtained for (E)-cinnamaldehyde (1.40 mg/ml), followed by thymol (2.04 mg/ml) and carvacrol (3.49 mg/ml). The same order of effectiveness was observed for D. nitens, with values of 1.68, 2.17 and 3.33 mg/ml, respectively. In the evaluation of component associations of essential oils against A. sculptum larvae, only the combinations between carvacrol and thymol (LC50) and carvacrol and (E)-cinnamaldehyde (1/4 LC50) presented a moderate synergetic effect. In turn, for D. nitens larvae, the combinations between thymol and carvacrol (LC50 and 1/2 LC50) presented a synergetic effect, while the others presented an additive or antagonistic effect. Therefore, it can be concluded that the combination of thymol and carvacrol (LC50) has a moderate synergetic effect against A. sculptum larvae, while thymol, combined with carvacrol (LC50 and 1/2 LC50), has a synergetic effect against D. nitens larvae. PMID:26346899

  18. The problem with value

    PubMed Central

    O’Doherty, John P.

    2015-01-01

    Neural correlates of value have been extensively reported in a diverse set of brain regions. However, in many cases it is difficult to determine whether a particular neural response pattern corresponds to a value-signal per se as opposed to an array of alternative non-value related processes, such as outcome-identity coding, informational coding, encoding of autonomic and skeletomotor consequences, alongside previously described “salience” or “attentional” effects. Here, I review a number of experimental manipulations that can be used to test for value, and I identify the challenges in ascertaining whether a particular neural response is or is not a value signal. Finally, I emphasize that some non-value related signals may be especially informative as a means of providing insight into the nature of the decision-making related computations that are being implemented in a particular brain region. PMID:24726573

  19. Demands, values, and burnout

    PubMed Central

    Leiter, Michael P.; Frank, Erica; Matheson, Timothy J.

    2009-01-01

    OBJECTIVE T o explore the interaction between workload and values congruence (personal values with health care system values) in the context of burnout and physician engagement and to explore the relative importance of these factors by sex, given the distinct work patterns of male and female physicians. DESIGN National mailed survey. SETTING Canada. PARTICIPANTS A random sample of 8100 Canadian physicians (response rate 40%, N = 3213); 2536 responses (from physicians working more than 35 hours per week) were analyzed. MAIN OUTCOME MEASURES Levels of burnout, values congruence, and workload, by sex, measured by the Maslach Burnout Inventory—General Scale and the Areas of Worklife Scale. RESULTS Results showed a moderate level of burnout among Canadian physicians, with relatively positive scores on exhaustion, average scores on cynicism, and mildly negative scores on professional efficacy. A series of multiple regression analyses confirmed parallel main effect contributions from manageable workload and values congruence. Both workload and values congruence predicted exhaustion and cynicism for men and women (P = .001). Only values congruence provided a significant prediction of professional efficacy for both men and women (P = .001) These predictors interacted for women on all 3 aspects of burnout (exhaustion, cynicism, and diminished efficacy). Howevever, overall levels of the burnout indicators departed only modestly from normative levels. CONCLUSION W orkload and values congruence make distinct contributions to physician burnout. Work overload contributes to predicting exhaustion and cynicism; professional values crises contribute to predicting exhaustion, cynicism, and low professional efficacy. The interaction of values and workload for women in particular has implications for the distinct work-life patterns of male and female physicians. Specifically, the congruence of individual values with values inherent in the health care system appeared to be of greater

  20. Business Value Game

    NASA Astrophysics Data System (ADS)

    Marchenko, Artem; Duarte, Vasco

    Agile teams want to deliver maximum business value. That’s easy if the on-site Ccstomer assigns business value to each story. But how does the customer do that? How can you estimate business value? This workshop is run as a game, where teams have to make tough business decisions for their ”organizations”. Teams have to decide which orders to take and what to deliver first in order to earn more. The session gives the participants basic business value estimation techniques, but the main point is to make people live through the business situation and to help them feel the consequences of various choices.

  1. Valuing Youth. Leader's Notebook.

    ERIC Educational Resources Information Center

    Glashagel, Jerry; And Others

    This leader's notebook is an attempt to present value education tools for persons working with elementary age children in various YMCA settings. These tools are value education strategies designed to stimulate discussion by the children and to help create a learning environment. The strategies are presented in two ways. First, a series of basic…

  2. How I Taught Values

    ERIC Educational Resources Information Center

    Pratt, Annis

    2005-01-01

    Values are principles or standards that people have decided are desirable to live by. The question of whether values can or should be taught to college students has been debated for decades, with the pros incorporating moral concepts into curricula and the antes scorning such efforts as not only inappropriate but also intellectually dull. In this…

  3. Do We Value Caring?

    ERIC Educational Resources Information Center

    Weissbourd, Richard; Anderson, Trisha Ross

    2016-01-01

    When asked about their child-rearing priorities, parents in the United States are likely to say it's more important to raise children who are caring than to raise high achievers. Schools, too, typically trumpet values such as caring, honesty, and fairness. These values are posted on walls, reiterated in assemblies, and included in mission…

  4. Looking for Core Values

    ERIC Educational Resources Information Center

    Carter, Margie

    2010-01-01

    People who view themselves as leaders, not just managers or teachers, are innovators who focus on clarifying core values and aligning all aspects of the organization with these values to grow their vision. A vision for an organization can't be just one person's idea. Visions grow by involving people in activities that help them name and create…

  5. Teaching Values through Drama.

    ERIC Educational Resources Information Center

    Berghammer, Gretta

    One dramatic technique to aid students in their discovery of values and value systems is "theatre-in-education" (TIE), a theatre event that takes place in schools, with actors working through roles for and with children. TIE aims to fuse education and theatre by having team members function as both teachers and actors, and the audiences of young…

  6. Work Values across Generations

    ERIC Educational Resources Information Center

    Hansen, Jo-Ida C.; Leuty, Melanie E.

    2012-01-01

    Mainstream publication discussions of differences in generational cohorts in the workplace suggest that individuals of more recent generations, such as Generation X and Y, have different work values than do individuals of the Silent and Baby Boom generations. Although extant research suggests that age may influence work values, few of the…

  7. Art's Educational Value

    ERIC Educational Resources Information Center

    Richmond, Stuart

    2009-01-01

    This paper explores critically the nature of art's value in education and argues in favor of both intrinsic and instrumental value. Form and expression, while being out of favor in some contemporary circles, are re-claimed as appropriate features of art. Concepts and forms in art as elsewhere serve to structure impressions and experience and…

  8. Sustaining NCTE Values

    ERIC Educational Resources Information Center

    Logan, Shirley Wilson

    2011-01-01

    NCTE's core values, posted on the website (http://www.ncte.org), are writing, literature, diversity, integrated language arts, knowledgeable and caring teachers, advocacy, and public education ("NCTE Core Values"). In this article, the author focuses only on writing, diversity, and advocacy, considering just a few ways in which the organization…

  9. Dance: Verities, Values, Visions.

    ERIC Educational Resources Information Center

    Boorman, Joyce, Ed.; Harris, Dorothy, Ed.

    The Binational Dance Conference was organized into three focal themes--verities, values, and visions in dance--to emphasize the known and accepted worth and value of dance, and to stimulate through knowledge and idea exchange, imaginative directions for dance in the future of both the United States and Canada. This thematic structure is also the…

  10. Cognitive and Social Values.

    ERIC Educational Resources Information Center

    Machamer, Peter; Douglas, Heather

    1999-01-01

    Criticizes Hugh Lacey's separation of cognitive values and social values in discussions of the nature of science. Claims that attempting to distinguish between cognitive and social ignores crucial complexities in the development and use of knowledge. Proposes that the proper distinction be between legitimate and illegitimate reasons in science as…

  11. High coking value pitch

    SciTech Connect

    Miller, Douglas J.; Chang, Ching-Feng; Lewis, Irwin C.; Lewis, Richard T.

    2014-06-10

    A high coking value pitch prepared from coal tar distillate and has a low softening point and a high carbon value while containing substantially no quinoline insolubles is disclosed. The pitch can be used as an impregnant or binder for producing carbon and graphite articles.

  12. Values Concepts and Techniques.

    ERIC Educational Resources Information Center

    National Education Association, Washington, DC.

    This book contains 29 articles for elementary and secondary teachers dealing with fundamental concepts and teaching techniques in values education. Part one of the book deals with concepts. Louis E. Raths examines valuing and its relationship to freedom and intelligence. The cognitive developmental approach to moral education is discussed by…

  13. Management Values Survey Results.

    ERIC Educational Resources Information Center

    Duffy, Barbara; Payne, Ron

    1988-01-01

    Describes results of a survey conducted to compare values of members of the Association for Educational Communications and Technology (AECT) with managers in business and industry. Issues discussed include job satisfaction, opportunities for advancement, attitudes toward management, and salary; a summary of each value system is provided. (LRW)

  14. Understanding Place Value

    ERIC Educational Resources Information Center

    Cooper, Linda L.; Tomayko, Ming C.

    2011-01-01

    Developing an understanding of place value and the base-ten number system is considered a fundamental goal of the early primary grades. For years, teachers have anecdotally reported that students struggle with place-value concepts. Among the common errors cited are misreading such numbers as 26 and 62 by seeing them as identical in meaning,…

  15. Rosenak "Teaching Jewish Values"

    ERIC Educational Resources Information Center

    Resnick, David

    2014-01-01

    Rosenak's "Teaching Jewish Values" (1986) is perhaps his most accessible book about Jewish education. After diagnosing the "diseases" of Jewish education, he endorses "teaching Jewish values" as the curricular strategy most likely to succeed given the chasm which divides traditional Jewish subject matter and the…

  16. Ecology and Human Values.

    ERIC Educational Resources Information Center

    1970

    "Ecology and Human Values" is an interdisciplinary course designed for senior year high school students in social studies and/or science. Its main thrust is the investigation of human values as they relate to the environment, although rooted in the natural sciences as a means of understanding the complexities inherent in the environment. Use is…

  17. The Value of the P Value

    PubMed Central

    Vyas, Dinesh; Balakrishnan, Archana; Vyas, Arpita

    2016-01-01

    Recently, the discussion on the implications of irreproducibility in the sciences has been brought into the spotlight. This topic has been discussed for years in the literature. A multitude of reasons have been attributed to this issue; one commonly labeled culprit is the overuse of the p value as a determinant of significance by the scientific community. Both scientists and statisticians have questioned the use of null hypothesis testing as the basis of scientific analysis. This survey of the current issues at hand in irreproducibility in research emphasizes potential causes of the issue, impacts that this can have for drug development and efforts been taken to increase transparency of findings in research. PMID:27430018

  18. Professional values and nursing.

    PubMed

    Sellman, Derek

    2011-05-01

    The values of nursing arise from a concern with human flourishing. If the desire to become a nurse is a reflection of an aspiration to care for others in need then we should anticipate that those who choose to nurse have a tendency towards the values we would normally associate with a caring profession (care, compassion, perhaps altruism, and so on). However, these values require a secure base if they are not to succumb to the corrupting pressures of the increasingly instrumental nature of the values of the institutions in which healthcare in general and nursing in particular takes place. One way of securing a base for withstanding the corrupting influences of the institution is to understand nursing as a practice in the sense in which Alasdair MacIntyre uses that term. In this brief paper I will outline ways in which the managerial imperative of meeting targets is both distorting practice and undermining nursing's values. I conclude that understanding nursing as a MacIntyrean practice provides a refuge from what might otherwise be overwhelming pressures for nurses to adopt instrumental values to the detriment of professional caring values. PMID:21061069

  19. Professional values and nursing.

    PubMed

    Sellman, Derek

    2011-05-01

    The values of nursing arise from a concern with human flourishing. If the desire to become a nurse is a reflection of an aspiration to care for others in need then we should anticipate that those who choose to nurse have a tendency towards the values we would normally associate with a caring profession (care, compassion, perhaps altruism, and so on). However, these values require a secure base if they are not to succumb to the corrupting pressures of the increasingly instrumental nature of the values of the institutions in which healthcare in general and nursing in particular takes place. One way of securing a base for withstanding the corrupting influences of the institution is to understand nursing as a practice in the sense in which Alasdair MacIntyre uses that term. In this brief paper I will outline ways in which the managerial imperative of meeting targets is both distorting practice and undermining nursing's values. I conclude that understanding nursing as a MacIntyrean practice provides a refuge from what might otherwise be overwhelming pressures for nurses to adopt instrumental values to the detriment of professional caring values.

  20. Can Schools Teach Values?

    ERIC Educational Resources Information Center

    Howe, Harold

    1987-01-01

    While the family is the main agency for helping young people develop the ideas, attitudes, and behavior of successful citizenship and work, schools can enrich the teacher-student relationship to the point that values rub off. (MT)

  1. Navigating Value Based Care.

    PubMed

    Sorrel, Amy Lynn

    2015-12-01

    TMA is collaborating with TMF Health Quality Institute to connect Texas physicians to free TMF resources that will better position doctors for the rapid transition to value-based payment. PMID:26630238

  2. Values in psychotherapy.

    PubMed

    Holmes, J

    1996-01-01

    There is a tension between those who hold that psychotherapy is a scientific discipline and therefore "value-free," and those who believe that values are inherent in the nature of psychotherapy. Psychoanalysis has moved from a science-based ideology, through the ethical concerns of Melanie Klein, to a recognition of the "aesthetic" dimension--the creation of suitable forms that can contain psychological distress. From this latter perspective, the antagonism between religion and psychotherapy, initiated by Freud, becomes less acute. Action-based ethical systems, which ignore the inner world, are critically scrutinized. The evidence suggesting there is a relationship between good outcome in psychotherapy and shared values between therapist and client is reviewed. It is posited that through examination of the "ethical countertransference," therapists should become aware of their own value systems and how they influence practice.

  3. Value of Information References

    DOE Data Explorer

    Morency, Christina

    2014-12-12

    This file contains a list of relevant references on value of information (VOI) in RIS format. VOI provides a quantitative analysis to evaluate the outcome of the combined technologies (seismology, hydrology, geodesy) used to monitor Brady's Geothermal Field.

  4. Working with Missing Values

    ERIC Educational Resources Information Center

    Acock, Alan C.

    2005-01-01

    Less than optimum strategies for missing values can produce biased estimates, distorted statistical power, and invalid conclusions. After reviewing traditional approaches (listwise, pairwise, and mean substitution), selected alternatives are covered including single imputation, multiple imputation, and full information maximum likelihood…

  5. Education and Values

    ERIC Educational Resources Information Center

    Inlow, Gail M.

    1972-01-01

    A selection from Values in Transition: A Handbook", its thesis is that formal education...has an obligation to educate broadly along lines of the intellectual, emotional, and social components, notjust the intellectual one per se." (Author)

  6. Economics: Mangroves' hidden value

    NASA Astrophysics Data System (ADS)

    Murray, Brian C.

    2012-11-01

    Mangroves are being lost at an alarming rate as their conversion for aquaculture and other uses is profitable. Research, however, suggests that valuing the deep reserves of carbon in mangrove sediments may be the key to their survival.

  7. Values in psychotherapy.

    PubMed

    Holmes, J

    1996-01-01

    There is a tension between those who hold that psychotherapy is a scientific discipline and therefore "value-free," and those who believe that values are inherent in the nature of psychotherapy. Psychoanalysis has moved from a science-based ideology, through the ethical concerns of Melanie Klein, to a recognition of the "aesthetic" dimension--the creation of suitable forms that can contain psychological distress. From this latter perspective, the antagonism between religion and psychotherapy, initiated by Freud, becomes less acute. Action-based ethical systems, which ignore the inner world, are critically scrutinized. The evidence suggesting there is a relationship between good outcome in psychotherapy and shared values between therapist and client is reviewed. It is posited that through examination of the "ethical countertransference," therapists should become aware of their own value systems and how they influence practice. PMID:8886227

  8. Values in action.

    PubMed

    Hearn, S A

    1997-01-01

    St. John Health System, Detroit, is committed to the values of wisdom, compassion, service to the neighbor, stewardship and servant leadership. When a patient walks through any one of the six St. John Hospitals, they see these words displayed many times. But what do they mean to the employees? Patients? The community? According to Anthony R. Tersigni, EdD, St. John president and CEO, "The values remind us of who we are and what our responsibilities are to the communities we serve."

  9. Value of Fundamental Science

    NASA Astrophysics Data System (ADS)

    Burov, Alexey

    Fundamental science is a hard, long-term human adventure that has required high devotion and social support, especially significant in our epoch of Mega-science. The measure of this devotion and this support expresses the real value of the fundamental science in public opinion. Why does fundamental science have value? What determines its strength and what endangers it? The dominant answer is that the value of science arises out of curiosity and is supported by the technological progress. Is this really a good, astute answer? When trying to attract public support, we talk about the ``mystery of the universe''. Why do these words sound so attractive? What is implied by and what is incompatible with them? More than two centuries ago, Immanuel Kant asserted an inseparable entanglement between ethics and metaphysics. Thus, we may ask: which metaphysics supports the value of scientific cognition, and which does not? Should we continue to neglect the dependence of value of pure science on metaphysics? If not, how can this issue be addressed in the public outreach? Is the public alienated by one or another message coming from the face of science? What does it mean to be politically correct in this sort of discussion?

  10. Getting Value from Research

    NASA Astrophysics Data System (ADS)

    Duke, Charles

    2004-03-01

    During the past decade the environment for and execution of industrial research has changed profoundly, as recently documented in Robert Buderi, Engines of Tomorrow (Simon and Shuster, New York, 2000). The vertically integrated single-firm research-through-product value chains of the twentieth century are gone, replaced by value chains the various elements of which can come from different firms in different parts of the world as described, e.g., by Henry W. Cheesbrough, Open Innovation (Harvard Business School Press, Boston, 2003). The consequences of this change are profound for national R policy, the R strategies of specific firms, and individual researchers. (See e.g., C. B. Duke, How to get value from R, Physics World, 17 (August 1997), 17.) In this presentation I sketch the strategies that firms employ to generate value from their research. Then I discuss the ingredients that are required to implement these strategies by creating value chains to deliver the fruits of research to customers. I indicate how the role of physical sciences is changing as unique hardware, based on advanced research in the physical sciences, becomes an increasingly minor (and often outsourced) component of integrated systems offerings. I close by noting implications of these developments on the nature of the careers that physicists can expect in industry and on the skills and cultural attributes that are required to be successful in the new industrial research environment.

  11. Confidentiality: a modified value.

    PubMed Central

    Emson, H E

    1988-01-01

    In its original expression as a medical value confidentiality may have been absolute; this concept has become eroded by patient consent, legal actions and change in the climate of public opinion. In particular requirements arising out of legal statutes and common law judgements have greatly modified the confidentiality of the doctor-patient relationship in societies deriving their law from English origins. Despite this, confidentiality remains a value which the physician must strive to preserve. He cannot however do this without considering its effect upon possible innocent third parties. PMID:3392723

  12. Leading Change, Adding Value.

    PubMed

    Evans, Nick

    2016-09-12

    Essential facts Leading Change, Adding Value is NHS England's new nursing and midwifery framework. It is designed to build on Compassion in Practice (CiP), which was published 3 years ago and set out the 6Cs: compassion, care, commitment, courage, competence and communication. CiP established the values at the heart of nursing and midwifery, while the new framework sets out how staff can help transform the health and care sectors to meet the aims of the NHS England's Five Year Forward View. PMID:27615573

  13. Value of space defenses

    SciTech Connect

    Canavan, G.H.

    1992-10-29

    This report discusses the economic value of defenses against Near-Earth Object (NEO) impacts is bounded by calculating expected losses in their absence, which illustrates the contributions from NEOs of different sizes and the sensitivity of total expected losses to impact frequencies. For typical size distributions and damage of only a few decades duration, losses are most sensitive to small NEOs, and lead to defenses worth a few $M/yr. When the persistence of damage with NEO size is taken into account, that shifts the loss to the largest NEOs and greatly increases expected loss and values.

  14. Value of Information spreadsheet

    DOE Data Explorer

    Trainor-Guitton, Whitney

    2014-05-12

    This spreadsheet represents the information posteriors derived from synthetic data of magnetotellurics (MT). These were used to calculate value of information of MT for geothermal exploration. Information posteriors describe how well MT was able to locate the "throat" of clay caps, which are indicative of hidden geothermal resources. This data is full explained in the peer-reviewed publication: Trainor-Guitton, W., Hoversten, G. M., Ramirez, A., Roberts, J., Júlíusson, E., Key, K., Mellors, R. (Sept-Oct. 2014) The value of spatial information for determining well placement: a geothermal example, Geophysics.

  15. [Acute Toxic Effects of Bromate on Aquatic Organisms].

    PubMed

    Wang, Zhi-wei; Liu, Dong-mei; Zhang, Wen-juan; Cui, Fu-yi

    2016-02-15

    Acute toxic effects of potassium bromate, sodium bromate and potassium bromide on luminescent bacteria, water flea, green alga and zebrafish were studied using standard toxic testing methods. The results showed that the pollutants had no effect on the luminous intensity of luminescent bacteria. The 96 h EC5. of potassium bromate on Scenedesmus obliquus was 738.18 mg x L(-1), 48 h EC50 on Daphnia magna and Moina was 154.01 mg x L(-1) was 161.80 mg x L(-1), while 48 h LC50 was 198 52 mg x L(-1), 175.68 mg x L(-1), and 96 h LC50 on zebrafish was 931.4 mg x L(-1). The 96 h EC50 of sodium bromate on Scenedesmus obliquus was 540.26 mg x L(-1), 48 h EC50 Daphnia magna and Moina was 127.90 mg x L(-1), 111.07 mg x L(-1), while 48 h LC50 was 161.80 mg x L(-1), 123.47 mg x L(-1), and 96 h LC50 on zebrafish was 1065.6 mg x L(-1). But the effects of potassium bromide on the above several kinds of aquatic organisms were far smaller than those of potassium bromate and sodium bromate. The toxic effects on test organisms were due to the impacts of bromate after the comparison of different pollutants, and the effects were more obvious with the increase of exposure time. The order of sensitivity to the toxic effects of bromate was Daphnia magna, Moina > Scenedesmus obliquus > zebrafish > Chlorella vulgaris, luminescent bacteria. PMID:27363170

  16. Sublethal concentrations of di-n-butyl phthalate promote biochemical changes and DNA damage in juvenile Nile tilapia (Oreochromis niloticus).

    PubMed

    Khalil, Samah R; Abd Elhakim, Yasser; El-Murr, Abd Elhakeem

    2016-02-01

    Increase in consumption of consumer items such as plasticizers have resulted in a sharp rise in the presence of xenobiotics like phthalic acid esters (PEs) in freshwater and marine environments due to contaminated runoff and improper release of effluents. The sublethal toxicity of Di-n-butyl phthalate (DBP) was investigated in juvenile Nile tilapia, Oreochromis niloticus, in an attempt to determine the biological effect of exposure to 1/2 and 1/3 median lethal concentration (96-h LC50) which, in our study was experimentally determined to be 11.8 mg/l. Following four days of exposure, indices of the oxidative potential [Malondialdehyde content (MDA)], antioxidant parameters [superoxide dismutase activity (SOD) and reduced glutathione level (GSH)] and DNA damage were evaluated by single-cell gel electrophoresis (Comet assay). Hepato-renal markers [alanine aminotransferase activity (ALT), creatinine and urea level] and cortisol levels were also quantified in serum. Additionally, histopathological investigations of liver, kidney and gill tissues were conducted. Comparative results between the 1/2 96-h LC50 group and the 1/3 96-h LC50 group clearly showed that there was a significant elevation in MDA levels and a marked increase in DNA damage in addition to inhibition of antioxidant barriers as represented by attenuation of SOD activity and GSH level in the group that was exposed to higher concentration of DBP (1/2 96-h LC50). The hepatorenal markers and cortisol levels were also observed to be elevated. Histopathological examination of the liver, kidney and gills showed pathological alterations that could be correlated with changes in the biochemical profile of the exposed fish. Additionally, anomalous clinical signs were noted. Based on these findings, we conclude from our study that exposure of juvenile O. niloticus to DBP has the potential to induce biochemical as well as tissue morphological alterations associated with oxidative injury and DNA damage. PMID:27348890

  17. Cardiomyocyte H9c2 cells present a valuable alternative to fish lethal testing for azoxystrobin.

    PubMed

    Rodrigues, Elsa T; Pardal, Miguel Â; Laizé, Vincent; Cancela, M Leonor; Oliveira, Paulo J; Serafim, Teresa L

    2015-11-01

    The present study aims at identifying, among six mammalian and fish cell lines, a sensitive cell line whose in vitro median inhibitory concentration (IC50) better matches the in vivo short-term Sparus aurata median lethal concentration (LC50). IC50s and LC50 were assessed after exposure to the widely used fungicide azoxystrobin (AZX). Statistical results were relevant for most cell lines after 48 h of AZX exposure, being H9c2 the most sensitive cells, as well as the ones which provided the best prediction of fish toxicity, with a LC50,96h/IC50,48h = 0.581. H9c2 cell proliferation upon 72 h of AZX exposure revealed a LC50,96h/IC50,72h = 0.998. Therefore, identical absolute sensitivities were attained for both in vitro and in vivo assays. To conclude, the H9c2 cell-based assay is reliable and represents a suitable ethical alternative to conventional fish assays for AZX, and could be used to get valuable insights into the toxic effects of other pesticides.

  18. Effect of sulfur dioxide on Swiss albino mice

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Machado, A. M.

    1977-01-01

    Times to incapacitation and death and LC50 values were determined for male Swiss albino mice exposed to different concentrations of sulfur dioxide in a 4.2 liter hemispherical chamber. The LC50 for a 30 minute exposure was about 3000 ppm SO2.

  19. Effect of nitrogen dioxide on Swiss albino mice

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Machado, A. M.

    1977-01-01

    Times to incapacitation and death and LC50 values were determined for male Swiss albino mice exposed to different concentrations of nitrogen dioxide in a 4.2 liter hemispherical chamber. The LC50 for a 10 minute exposure was about 1000 ppm NO2.

  20. Effect of ammonia on Swiss albino mice

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Casey, C. J.; Furst, A.

    1977-01-01

    Times to incapacitation and death and LC /50/ values were determined for Swiss albino male mice exposed to different concentrations of ammonia in a 4.2 liter hemispherical chamber. The LC/50/ for a 30 minute exposure was 21,430 ppm.

  1. Valuing Higher Education

    ERIC Educational Resources Information Center

    Pillay, Gerald J.

    2009-01-01

    The question of the value of higher education is today set in the context of an unprecedented banking and financial crisis. In this context of fundamental change and financial realignment, it is important that we as members of the university remake our case for why the university deserves to be considered alongside all those other worthy causes…

  2. Easy Absolute Values? Absolutely

    ERIC Educational Resources Information Center

    Taylor, Sharon E.; Mittag, Kathleen Cage

    2015-01-01

    The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…

  3. Materialistic Values and Goals.

    PubMed

    Kasser, Tim

    2016-01-01

    Materialism comprises a set of values and goals focused on wealth, possessions, image, and status. These aims are a fundamental aspect of the human value/goal system, standing in relative conflict with aims concerning the well-being of others, as well as one's own personal and spiritual growth. Substantial evidence shows that people who place a relatively high priority on materialistic values/goals consume more products and incur more debt, have lower-quality interpersonal relationships, act in more ecologically destructive ways, have adverse work and educational motivation, and report lower personal and physical well-being. Experimentally activating materialistic aims causes similar outcomes. Given these ills, researchers have investigated means of decreasing people's materialism. Successful interventions encourage intrinsic/self-transcendent values/goals, increase felt personal security, and/or block materialistic messages from the environment. These interventions would likely be more effective if policies were also adopted that diminished contemporary culture's focus on consumption, profit, and economic growth.

  4. Not Without Value. Editorial.

    ERIC Educational Resources Information Center

    Buck, George H.

    2002-01-01

    To reverse the decline in volunteerism in education, administrators must understand the difference between true volunteering and participation coerced under the guise of volunteering. Appreciation is essential for promoting volunteerism, for no one wishes to be considered without value. But if coercion and exploitation are part of the growing…

  5. Communication and Values.

    ERIC Educational Resources Information Center

    Sillars, Malcolm O.

    Communication experts and researchers have done little to help prepare themselves or others to cope with values in the communication revolution that is taking place. The problem goes beyond the influence the media has in the United States; it has implications of international issues of survival. What is needed is an emphasis on research and…

  6. Classifying Values by Categories

    ERIC Educational Resources Information Center

    Gündüz, Mevlüt

    2016-01-01

    The aim of this study is to make a new classification regarding the fact that the current classifications may change constantly because of values? gaining a different dimension and importance every single day. In this research descriptive research, which was used frequently in qualitative research methods, was preferred. This research was…

  7. Technostress and Library Values.

    ERIC Educational Resources Information Center

    Gorman, Michael

    2001-01-01

    Discusses information overload and society's and libraries' responses to technology. Considers eight values that libraries should focus on and how they relate to technology in libraries: democracy, stewardship, service, intellectual freedom, privacy, rationalism, equity of access, and building harmony and balance. (LRW)

  8. The Value of Pretending.

    ERIC Educational Resources Information Center

    Segal, Marilyn; Adcock, Don

    By participating in their children's imaginative play or pretending, parents may be able to understand better their children's feelings, resolve parent-child conflicts, communicate parental values, and build parent-child relationships based on mutual respect. Many people seem to believe that pretending appears automatically in young children, that…

  9. Public Values, Private Schools.

    ERIC Educational Resources Information Center

    Devins, Neal E.

    Controversy surrounding private education involves questions of compulsory education's role in inculcating values, how much alike public and private schools should be, and the duty of educational institutions to conform to constitutional norms. This book examines government regulation and resistance, legislative and judicial approaches, and issues…

  10. Making People Feel Valued.

    ERIC Educational Resources Information Center

    Fergueson, Susan; Aimone, Logan

    2002-01-01

    Suggests many quick, easy and inexpensive ways to help make staff members of student publications feel valued and keep staff motivation levels high. Includes additional articles that describe how an editor can support efforts to motivate, suggest that staff retreats lead to success, note how banquets serve as reward, and suggest some favorite…

  11. Developing Human Values.

    ERIC Educational Resources Information Center

    Hall, Brian P.; And Others

    The process by which human beings, as they grow toward maturity, develop values is not an automatic one. The process can be fostered by a number of teaching strategies. The strategies include the techniques of self-discovery, the provision of learning environments that encourage growth, and the practice of specific skills. This volume provides a…

  12. Prevent and "British Values"

    ERIC Educational Resources Information Center

    Kenny, Alex; Ghale, Baljeet

    2015-01-01

    At the recent National Union of Teachers' conference the role of the Prevent strategy and the introduction of "British Values" in the Office for Standards in Education, Children's Services and Skills framework emerged as key issues for delegates. Two of the speeches made at the conference are presented here.

  13. Whose Religious Values?

    ERIC Educational Resources Information Center

    Marshall, Joanne M.

    2008-01-01

    Public schools, since their founding in America in 1647, have reflected the demographic characteristics of the communities in which they are located. Because the United States has, until recently, been mostly Protestant Christian, many schooling practices have built upon the values of this faith. Pupils have sung Christmas songs at Christmas…

  14. Researching Values in Education.

    ERIC Educational Resources Information Center

    Halliday, John

    2002-01-01

    Considers methodological issues that arise when values form the main focus of empirical educational research. Includes discussion of the idea that social science, in general, and educational research, in particular, are forms of moral inquiry. Outlines a methodology of educational research, drawing from work by Imre Lakatos, Alasdair MacIntyre,…

  15. Values in Literature: Primary.

    ERIC Educational Resources Information Center

    Sterling, Mary Ellen

    Offering students some thinking and coping tools they can use to make sound decisions based on strong values, this resource book presents numerous selections from children's literature and suggested activities and projects. The book begins with a brief introduction, advice to teachers on using the book, ways to make the classroom more conducive to…

  16. Toxic Effect of a Marine Bacterium on Aquatic Organisms and Its Algicidal Substances against Phaeocystis globosa

    PubMed Central

    Yang, Qiuchan; Chen, Lina; Hu, Xiaoli; Zhao, Ling; Yin, Pinghe; Li, Qiang

    2015-01-01

    Harmful algal blooms have caused enormous damage to the marine ecosystem and the coastal economy in China. In this paper, a bacterial strain B1, which had strong algicidal activity against Phaeocystis globosa, was isolated from the coastal waters of Zhuhai in China. The strain B1 was identified as Bacillus sp. on the basis of 16S rDNA gene sequence and morphological characteristics. To evaluate the ecological safety of the algicidal substances produced by strain B1, their toxic effects on marine organisms were tested. Results showed that there were no adverse effects observed in the growth of Chlorella vulgaris, Chaetoceros muelleri, and Isochrystis galbana after exposure to the algicidal substances at a concentration of 1.0% (v/v) for 96 h. The 48h LC50 values for Brachionus plicatilis, Moina mongolica Daday and Paralichthys olivaceus were 5.7, 9.0 and 12.1% (v/v), respectively. Subsequently, the algicidal substances from strain B1 culture were isolated and purified by silica gel column, Sephadex G-15 column and high-performance liquid chromatography. Based on quadrupole time-of-flight mass spectrometry and PeakView Software, the purified substances were identified as prolyl-methionine and hypoxanthine. Algicidal mechanism indicated that prolyl-methionine and hypoxanthine inhibited the growth of P. globosa by disrupting the antioxidant systems. In the acute toxicity assessment using M. mongolica, 24h LC50 values of prolyl-methionine and hypoxanthine were 7.0 and 13.8 g/L, respectively. The active substances produced by strain B1 can be considered as ecologically and environmentally biological agents for controlling harmful algal blooms. PMID:25646807

  17. Toxic effect of a marine bacterium on aquatic organisms and its algicidal substances against Phaeocystis globosa.

    PubMed

    Yang, Qiuchan; Chen, Lina; Hu, Xiaoli; Zhao, Ling; Yin, Pinghe; Li, Qiang

    2015-01-01

    Harmful algal blooms have caused enormous damage to the marine ecosystem and the coastal economy in China. In this paper, a bacterial strain B1, which had strong algicidal activity against Phaeocystis globosa, was isolated from the coastal waters of Zhuhai in China. The strain B1 was identified as Bacillus sp. on the basis of 16S rDNA gene sequence and morphological characteristics. To evaluate the ecological safety of the algicidal substances produced by strain B1, their toxic effects on marine organisms were tested. Results showed that there were no adverse effects observed in the growth of Chlorella vulgaris, Chaetoceros muelleri, and Isochrystis galbana after exposure to the algicidal substances at a concentration of 1.0% (v/v) for 96 h. The 48h LC50 values for Brachionus plicatilis, Moina mongolica Daday and Paralichthys olivaceus were 5.7, 9.0 and 12.1% (v/v), respectively. Subsequently, the algicidal substances from strain B1 culture were isolated and purified by silica gel column, Sephadex G-15 column and high-performance liquid chromatography. Based on quadrupole time-of-flight mass spectrometry and PeakView Software, the purified substances were identified as prolyl-methionine and hypoxanthine. Algicidal mechanism indicated that prolyl-methionine and hypoxanthine inhibited the growth of P. globosa by disrupting the antioxidant systems. In the acute toxicity assessment using M. mongolica, 24h LC50 values of prolyl-methionine and hypoxanthine were 7.0 and 13.8 g/L, respectively. The active substances produced by strain B1 can be considered as ecologically and environmentally biological agents for controlling harmful algal blooms.

  18. Toxicity of aircraft de-icer and anti-icer solutions to aquatic organisms

    SciTech Connect

    Hartwell, S.I.; Jordahl, D.M.; Evans, J.E.; May, E.B.

    1995-08-01

    Laboratory studies were undertaken to assess the toxicity of industrial mixtures of aviation de-icers and anti-icers. Various additives and contaminants are present in these solutions at proportions of 10 to 20% of the total volume. Static-renewal toxicity tests were performed at concentrations that bracketed published LC50 values for the primary ingredients (9--51 ml glycol/L) using fathead minnow (Pimephales promelas), Daphnia magna, Daphnia pulex, Ceriodaphnia dubia, and Photobacterium phosphoreum (Microtox{reg_sign}) bioassays. Water from a stream that receives runoff from a large commercial airport was also tested during a late winter storm (March), and spring baseflow (April). The anti-icer solution was more toxic than the de-icer solution by two orders of magnitude (96-h LC50 range 0.03-0.44 ml/L, 3.02--13.48 ml/L, respectively). Both types of solutions exhibited greater toxicity than previously reported values for the primary ingredients. Toxic effects were observed in the March stream sample, but not the April sample. Significant inhibition of reproduction in C. dubia in the anti-icer and de-icer solutions occurred at 0.05 and 0.38 ml/L, respectively. Effects were observed in the Microtox assay at concentrations of 0.125 and 0.25 ml/L for the anti-icer and de-icer, respectively. Results suggest that the additives, rather than the glycols, are the major source of toxicity. Histological damage observed in fathead minnows primarily involved gill, kidney, and skin tissue, with the most prominent responses seen in fish exposed to the anti-icer solution. The de-icer solution elicited respiratory epithelial ``disruption`` and renal damage, and the anti-icer caused proliferative branchitis (hyperplastic response) and delamination of the epidermis from the dermis of the skin.

  19. Toxic effect of a marine bacterium on aquatic organisms and its algicidal substances against Phaeocystis globosa.

    PubMed

    Yang, Qiuchan; Chen, Lina; Hu, Xiaoli; Zhao, Ling; Yin, Pinghe; Li, Qiang

    2015-01-01

    Harmful algal blooms have caused enormous damage to the marine ecosystem and the coastal economy in China. In this paper, a bacterial strain B1, which had strong algicidal activity against Phaeocystis globosa, was isolated from the coastal waters of Zhuhai in China. The strain B1 was identified as Bacillus sp. on the basis of 16S rDNA gene sequence and morphological characteristics. To evaluate the ecological safety of the algicidal substances produced by strain B1, their toxic effects on marine organisms were tested. Results showed that there were no adverse effects observed in the growth of Chlorella vulgaris, Chaetoceros muelleri, and Isochrystis galbana after exposure to the algicidal substances at a concentration of 1.0% (v/v) for 96 h. The 48h LC50 values for Brachionus plicatilis, Moina mongolica Daday and Paralichthys olivaceus were 5.7, 9.0 and 12.1% (v/v), respectively. Subsequently, the algicidal substances from strain B1 culture were isolated and purified by silica gel column, Sephadex G-15 column and high-performance liquid chromatography. Based on quadrupole time-of-flight mass spectrometry and PeakView Software, the purified substances were identified as prolyl-methionine and hypoxanthine. Algicidal mechanism indicated that prolyl-methionine and hypoxanthine inhibited the growth of P. globosa by disrupting the antioxidant systems. In the acute toxicity assessment using M. mongolica, 24h LC50 values of prolyl-methionine and hypoxanthine were 7.0 and 13.8 g/L, respectively. The active substances produced by strain B1 can be considered as ecologically and environmentally biological agents for controlling harmful algal blooms. PMID:25646807

  20. Evaluation of cytotoxicity and genotoxicity of insecticide carbaryl to flounder gill cells and its teratogenicity to zebrafish embryos

    NASA Astrophysics Data System (ADS)

    Pandey, Manish Raj; Guo, Huarong

    2015-04-01

    In this study, we determined the cytotoxicity and genotoxicity of carbamate insecticide carbaryl to flounder gill (FG) cells and its teratogenicity to zebrafish embryos. The cytotoxicity of carbaryl to FG cells was determined with methods including MTT and neutral red uptaking (NRU), lactate dehydrogenase (LDH) releasing and Hoechst 33342 and propidium idodide (PI) double staining. Moderate cytotoxicity in a concentration-dependent manner was observed. The 24 h-IC50 value of 53.48 ± 1.21, 59.13 ± 1.19 and 46.21 ± 1.24 mg L-1 carbaryl was obtained through MTT, NRU and LDH assays, respectively. Double fluorescence staining demonstrated that carbaryl induced the death of FG cells mainly through necrosis. There was no significant genotoxicity found in the FG cells exposed to the highest testing concentration of carbaryl (20 mg L-1, P > 0.05) as was demonstrated by Comet assay. Zebrafish embryos exposed to carbaryl at concentrations ≥10 mg L-1 displayed moderate toxic effects on the survival, spontaneous movement, hatching, heart rates of the embryos and their development, which were evidenced by yolk and pericardial sac edemas, body length reduction and tail flexure in time- and concentration-dependent manners at specific stages. The 24 h-, 48 h- and 96 h-LC50 values of carbaryl to zebrafish embryos were 41.80 ± 1.10, 17.80 ± 1.04 and 14.46 ± 1.05 mg L-1, respectively. These results suggested that carbaryl is moderately toxic to FG cells cultured in vitro and zebrafish embryos, and the FG cells were similar to zebrafish embryos in their sensitivity to carbaryl as 24 h-IC50 and LC50 indicated.

  1. Transfer modelling and toxicity evaluation of the effluent from an installation of cleansing and uranium recovery using a battery of bioassays.

    PubMed

    Gagnaire, Béatrice; Boyer, Patrick; Bonzom, Jean-Marc; Lecomte-Pradines, Catherine; Simon, Olivier; Gilbin, Rodolphe

    2011-01-01

    On July 7, 2008, a leak of effluent from an Installation of Cleansing and Uranium Recovery (Tricastin, France) led to the spillage of uranium in a stream. The acute toxicity of the effluent was evaluated, and compared to the toxicity of uranium nitrate in bioassays using several organisms: Chlamydomonas reinhardtii, Daphnia magna, Chironomus riparius and Danio rerio. A sediment bioassay was also performed on C. riparius using water and sediment sampled along the river. Results showed that effluent EC(50) 72 h was 0.65 mg U/l for algae and LC(50) 48 h was 1.67 mg U/l for daphnia, while values obtained for uranium nitrate were higher. The LC(50) 96 h of effluent to C. riparius was 22.7 mg U/l, similar to value for uranium nitrate; the sediment collected was not toxic to C. riparius larvae. The LOEC of effluent and uranium nitrate on HT(50) of D. rerio were similar (0.03 mg U/l), but larvae were more sensitive to uranium nitrate than to effluent. Our results suggest that other substances contained in the effluent could potentially be toxic to wildlife in association with uranium. In parallel, the modelling of the transfers based on uranium measurements in the surface water was used to fill data gaps and assess the impact along the river. These results provided an estimate of exposure conditions that occurred along the river. This approach allowed us to see that the risk to ecosystem during this incident was certainly low and concerned a short period of time, but it could have existed at least for some species.

  2. Estimating fermentation characteristics and nutritive value of ensiled and dried pomegranate seeds for ruminants using in vitro gas production technique

    PubMed Central

    Taher-Maddah, M.; Maheri-Sis, N.; Salamatdoustnobar, R.; Ahmadzadeh, A.

    2012-01-01

    The purpose of this study was to determine the chemical composition and estimation of fermentation characteristics and nutritive value of ensiled and dried pomegranate seeds using in vitro gas production technique. Samples were collected, mixed, processed (ensiled and dried) and incubated in vitro with rumen liquor taken from three fistulated Iranian native (Taleshi) steers at 2, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96 h. The results showed that ensiling lead to significant increase in gas production of pomegranate seeds at all incubation times. The gas volume at 24 h incubation, were 25.76 and 17.91 ml/200mg DM for ensiled and dried pomegranate seeds, respectively. The gas production rate (c) also was significantly higher for ensiled groups than dried (0.0930 vs. 0.0643 ml/h). The organic matter digestibility (OMD), metabolizable energy (ME), net energy for lactation (NEL) and short chain fatty acids (SCFA) of ensiled pomegranate seeds were significantly higher than that of dried samples (43.15%, 6.37 MJ/kg DM, 4.43 MJ/kg DM, 0.5553 mmol for ensiled samples vs. 34.62%, 5.10 MJ/kg DM, 3.56 MJ/kg DM, 0.3680 mmol for dried samples, respectively). It can be concluded that ensiling increases the nutritive value of pomegranate seeds. PMID:26623290

  3. Mortality of a wireworm, Agriotes obscurus (Coleoptera: Elateridae), after topical application of various insecticides.

    PubMed

    Van Herk, W G; Vernon, R S; Tolman, J H; Saavedra, H Ortiz

    2008-04-01

    Ten insecticides representing seven chemical groups were applied at various concentrations topically by using a Potter Spray Tower to evaluate their relative toxicities on the European wireworm Agriotes obscurus L. (Coleoptera: Elateridae). Wireworms were stored at 15 degrees C after exposure to organophosphate (OP) (chlorpyrifos, diazinon), pyrethroid (tefluthrin), thianicotinoid (thiamethoxam, clothianidin), chloronicotinoid (imidacloprid, acetamiprid), phenyl pyrazole (fipronil), organochlorine (lindane), and spinosyn (spinosad) insecticides, and their postapplication health was evaluated weekly for up to 301 d. LC50, LC90, LT50, and LT90 values were calculated for each chemical except acetamiprid, and compared with those of lindane, clothianidin, and chlorpyrifos. Wireworms exposed to OPs died or recovered more quickly (LT50 < 20 d, LT90 < 50 d), than those exposed to all other insecticides tested except tefluthrin (LT50 = 25.5 d, LT90 = 66.5 d). Wireworms exposed to sublethal concentrations of all neonicotinoids quickly became moribund after application but made a full recovery. Wireworms exposed to fipronil at concentrations near the LC90 value showed no intoxication symptoms for up to 35 d, and they did not recover after symptoms developed. For each chemical, increasing the concentration increased the time required for wireworms to recover but decreased the time required to kill wireworms. Fipronil was highly toxic to wireworms (LC50 = 0.0001%), but acetamiprid (LC50 = 1.82%), imidacloprid (LC50 = 0.83%), tefluthrin (LC50 = 0.23%), diazinon (LC50 = 0.54%), and spinosad (LC50 = 0.51%) were not. The toxicity of both clothianidin (LC50 = 0.07%) and thiamethoxam (LC50 = 0.17%) were similar to those oflindane (LC50 = 0.06%) and chlorpyrifos (LC50 = 0.10%).

  4. Radiology's value chain.

    PubMed

    Enzmann, Dieter R

    2012-04-01

    A diagnostic radiology value chain is constructed to define its main components, all of which are vulnerable to change, because digitization has caused disaggregation of the chain. Some components afford opportunities to improve productivity, some add value, while some face outsourcing to lower labor cost and to information technology substitutes, raising commoditization risks. Digital image information, because it can be competitive at smaller economies of scale, allows faster, differential rates of technological innovation of components, initiating a centralization-to-decentralization technology trend. Digitization, having triggered disaggregation of radiology's professional service model, may soon usher in an information business model. This means moving from a mind-set of "reading images" to an orientation of creating and organizing information for greater accuracy, faster speed, and lower cost in medical decision making. Information businesses view value chain investments differently than do small professional services. In the former model, producing a better business product will extend image interpretation beyond a radiologist's personal fund of knowledge to encompass expanding external imaging databases. A follow-on expansion with integration of image and molecular information into a report will offer new value in medical decision making. Improved interpretation plus new integration will enrich and diversify radiology's key service products, the report and consultation. A more robust, information-rich report derived from a "systems" and "computational" radiology approach will be facilitated by a transition from a professional service to an information business. Under health care reform, radiology will transition its emphasis from volume to greater value. Radiology's future brightens with the adoption of a philosophy of offering information rather than "reads" for decision making. Staunchly defending the status quo via turf wars is unlikely to constitute a

  5. Toxicity of an herbicide and adjuvant to saltmarsh invertebrates in the management of invasive grass; Comparative laboratory and field tests.

    PubMed

    Kleinhenz, Linda S; Nugegoda, Dayanthi; Verspaandonk, Emily R; Coombes, Darcy C; Howe, Steffan; Shimeta, Jeff

    2016-08-15

    Coastal weeds are often treated with herbicides without knowledge of non-target impacts, and toxicity data from standardized test species can have limited applicability. We evaluated toxicity to invertebrates from Fusilade Forte® and the adjuvant Hasten® in the control of invasive salt marsh grass, Spartina anglica. For 3 of 4 local invertebrates, Fusilade Forte® was moderately toxic (96h LC50 5.4-144mgL(-1)), whereas Hasten® was less toxic (14.2-450mgL(-1)). For most species, the mixture was more toxic than the herbicide alone, with 96h LC50 reduced 23-45%. However, a field experiment applying typical concentrations (1000×the lowest 96h LC50) showed low concentrations of herbicide residues and no detrimental impacts on invertebrates over 6months. The results reveal the importance of testing locally relevant species for potential toxicity, and of comparison tests with field exposures to determine the realised toxicity in nature. PMID:27262496

  6. Bivariate extreme value distributions

    NASA Technical Reports Server (NTRS)

    Elshamy, M.

    1992-01-01

    In certain engineering applications, such as those occurring in the analyses of ascent structural loads for the Space Transportation System (STS), some of the load variables have a lower bound of zero. Thus, the need for practical models of bivariate extreme value probability distribution functions with lower limits was identified. We discuss the Gumbel models and present practical forms of bivariate extreme probability distributions of Weibull and Frechet types with two parameters. Bivariate extreme value probability distribution functions can be expressed in terms of the marginal extremel distributions and a 'dependence' function subject to certain analytical conditions. Properties of such bivariate extreme distributions, sums and differences of paired extremals, as well as the corresponding forms of conditional distributions, are discussed. Practical estimation techniques are also given.

  7. Education: A Core Value

    NASA Astrophysics Data System (ADS)

    Carroll, William F., Jr.

    2001-09-01

    1. Teaching our Children. ACS should develop an intensive course in modern teaching methods, challenges and responsibilities, and press for streamlined teacher certification procedures for advanced degree or life experience chemists.
    2. Teaching our Future Colleagues. As President I will encourage companies to make scientists with special skills available to universities, and will encourage universities to utilize these scientists to round out areas of study not covered by their existing faculty.
    3. Teaching our Members. ACS should develop functional and management-related courses for scientists to facilitate career advancement from the bench to research management or from science to business.
    4. Teaching the Public. The President is the most visible representative of the Society, and should devote significant time to communication with lay audiences.
    Value Matters. My first priority as President will be to increase value creation, communication and quantification so members can easily identify programs that fill their needs and exceed their expectations.

  8. Global Value Trees

    PubMed Central

    Zhu, Zhen; Puliga, Michelangelo; Cerina, Federica; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    The fragmentation of production across countries has become an important feature of the globalization in recent decades and is often conceptualized by the term “global value chains” (GVCs). When empirically investigating the GVCs, previous studies are mainly interested in knowing how global the GVCs are rather than how the GVCs look like. From a complex networks perspective, we use the World Input-Output Database (WIOD) to study the evolution of the global production system. We find that the industry-level GVCs are indeed not chain-like but are better characterized by the tree topology. Hence, we compute the global value trees (GVTs) for all the industries available in the WIOD. Moreover, we compute an industry importance measure based on the GVTs and compare it with other network centrality measures. Finally, we discuss some future applications of the GVTs. PMID:25978067

  9. Complex-valued autoencoders.

    PubMed

    Baldi, Pierre; Lu, Zhiqin

    2012-09-01

    Autoencoders are unsupervised machine learning circuits, with typically one hidden layer, whose learning goal is to minimize an average distortion measure between inputs and outputs. Linear autoencoders correspond to the special case where only linear transformations between visible and hidden variables are used. While linear autoencoders can be defined over any field, only real-valued linear autoencoders have been studied so far. Here we study complex-valued linear autoencoders where the components of the training vectors and adjustable matrices are defined over the complex field with the L(2) norm. We provide simpler and more general proofs that unify the real-valued and complex-valued cases, showing that in both cases the landscape of the error function is invariant under certain groups of transformations. The landscape has no local minima, a family of global minima associated with Principal Component Analysis, and many families of saddle points associated with orthogonal projections onto sub-space spanned by sub-optimal subsets of eigenvectors of the covariance matrix. The theory yields several iterative, convergent, learning algorithms, a clear understanding of the generalization properties of the trained autoencoders, and can equally be applied to the hetero-associative case when external targets are provided. Partial results on deep architecture as well as the differential geometry of autoencoders are also presented. The general framework described here is useful to classify autoencoders and identify general properties that ought to be investigated for each class, illuminating some of the connections between autoencoders, unsupervised learning, clustering, Hebbian learning, and information theory.

  10. The value of certification.

    PubMed

    Kaplow, Roberta

    2011-01-01

    Certification is defined in the nursing literature in several ways; no one consistent definition of certification exists. Nursing specialty certification programs are intended for consumer protection. Certification protects the public by enabling consumers to identify competent people more readily. However, benefits for stakeholders other than patients and families are also described in the literature. This article describes the value of specialty certification from the perspective of the patient and family, nurse, and employer.

  11. Minimum Critical Values Study

    SciTech Connect

    Fox, P.B.

    2005-07-11

    This report provides minimum critical values for various 30-cm water-reflected uranium and plutonium oxide and nitrate aqueous mixtures as calculated by the SCALE CSAS1X sequence using the 238-group ENDF/B-V neutron cross-section library. The minimum values were determined through parametric searches in one-dimensional geometry. The calculations have been performed to obtain the minimum values: critical volume and mass for spheres, critical radius for cylinders, critical thickness for slabs, and minimum critical concentration (infinite geometry) for the following homogeneous mixtures: (1) UO{sub 2}-H{sub 2}O for 3, 4, 5, 20, and 100 wt % {sup 235}U; (2) UNH for 3, 4, 5, 20, and 100 wt % {sup 235}U; (3) PuO{sub 2}-H{sub 2}O for 100/0/0, 95/5/0, 90/5/5, 80/10/10, and 71/17/11/1 wt % of {sup 239}Pu/{sup 240}Pu/{sup 241}Pu(/{sup 242}Pu); and (4) PuNH for 100/0/0, 95/5/0, 90/5/5, 80/10/10, and 71/17/11/1 wt % of {sup 239}Pu/{sup 240}Pu/{sup 241}Pu(/{sup 242}Pu). All bounding surfaces were fully reflected by 30 cm of H{sub 2}O.

  12. Impact of natural organic matter on particle behavior and phototoxicity of titanium dioxide nanoparticles.

    PubMed

    Li, Shibin; Ma, Hongbo; Wallis, Lindsay K; Etterson, Matthew A; Riley, Benjamin; Hoff, Dale J; Diamond, Stephen A

    2016-01-15

    Due to their inherent phototoxicity and inevitable environmental release, titanium dioxide nanoparticles (nano-TiO2) are increasingly studied in the field of aquatic toxicology. One of the particular interests is the interactions between nano-TiO2 and natural organic matter (NOM). In this study, a series of experiments was conducted to study the impacts of Suwannee River natural organic matter (SRNOM) on phototoxicity and particle behaviors of nano-TiO2. For Daphnia magna, after the addition of 5mg/L SRNOM, LC50 value decreased significantly from 1.03 (0.89-1.20) mg/L to 0.26 (0.22-0.31) mg/L. For zebrafish larvae, phototoxic LC50 values were 39.9 (95% CI, 25.9-61.2) mg/L and 26.3 (95% CI, 18.3-37.8) mg/L, with or without the presence of 5mg/L SRNOM, respectively. There was no statistically significant change of these LC50 values. The impact of SRNOM on phototoxicity of nano-TiO2 was highly dependent on test species, with D. magna being the more sensitive species. The impact on particle behavior was both qualitatively and quantitatively examined. A global predictive model for particle behavior was developed with a three-way interaction of SRNOM, TiO2 concentration, and time and an additive effect of ionic strength. Based on power analyses, 96-h exposure in bioassays was recommended for nanoparticle-NOM interaction studies. The importance of reactive oxygen species (ROS) quenching of SRNOM was also systematically studied using a novel exposure system that isolates the effects of environmental factors. These experiments were conducted with minimal impacts of other important interaction mechanisms (NOM particle stabilization, NOM UV attenuation, and NOM photosensitization). This study highlighted both the particle stabilization and ROS quenching effects of NOM on nano-TiO2 in an aquatic system. There is an urgent need for representative test materials, together with key environmental factors, for future risk assessment and regulations of nanomaterials.

  13. Impact of natural organic matter on particle behavior and phototoxicity of titanium dioxide nanoparticles.

    PubMed

    Li, Shibin; Ma, Hongbo; Wallis, Lindsay K; Etterson, Matthew A; Riley, Benjamin; Hoff, Dale J; Diamond, Stephen A

    2016-01-15

    Due to their inherent phototoxicity and inevitable environmental release, titanium dioxide nanoparticles (nano-TiO2) are increasingly studied in the field of aquatic toxicology. One of the particular interests is the interactions between nano-TiO2 and natural organic matter (NOM). In this study, a series of experiments was conducted to study the impacts of Suwannee River natural organic matter (SRNOM) on phototoxicity and particle behaviors of nano-TiO2. For Daphnia magna, after the addition of 5mg/L SRNOM, LC50 value decreased significantly from 1.03 (0.89-1.20) mg/L to 0.26 (0.22-0.31) mg/L. For zebrafish larvae, phototoxic LC50 values were 39.9 (95% CI, 25.9-61.2) mg/L and 26.3 (95% CI, 18.3-37.8) mg/L, with or without the presence of 5mg/L SRNOM, respectively. There was no statistically significant change of these LC50 values. The impact of SRNOM on phototoxicity of nano-TiO2 was highly dependent on test species, with D. magna being the more sensitive species. The impact on particle behavior was both qualitatively and quantitatively examined. A global predictive model for particle behavior was developed with a three-way interaction of SRNOM, TiO2 concentration, and time and an additive effect of ionic strength. Based on power analyses, 96-h exposure in bioassays was recommended for nanoparticle-NOM interaction studies. The importance of reactive oxygen species (ROS) quenching of SRNOM was also systematically studied using a novel exposure system that isolates the effects of environmental factors. These experiments were conducted with minimal impacts of other important interaction mechanisms (NOM particle stabilization, NOM UV attenuation, and NOM photosensitization). This study highlighted both the particle stabilization and ROS quenching effects of NOM on nano-TiO2 in an aquatic system. There is an urgent need for representative test materials, together with key environmental factors, for future risk assessment and regulations of nanomaterials. PMID:26519592

  14. Essential oils with insecticidal activity against larvae of Aedes aegypti (Diptera: Culicidae).

    PubMed

    Vera, Sharon Smith; Zambrano, Diego Fernando; Méndez-Sanchez, Stelia Carolina; Rodríguez-Sanabria, Fernando; Stashenko, Elena E; Duque Luna, Jonny E

    2014-07-01

    Insecticidal activity of the essential oils (EOs) isolated from Tagetes lucida, Lippia alba, Lippia origanoides, Eucalyptus citriodora, Cymbopogon citratus, Cymbopogon flexuosus, Citrus sinensis, Swinglea glutinosa, and Cananga odorata aromatic plants, grown in Colombia (Bucaramanga, Santander), and of a mixture of L. alba and L. origanoides EOs were evaluated on Aedes (Stegomyia) aegypti Rockefeller larvae. The EOs were extracted by microwave-assisted hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS). The main components of the EOs were identified using their linear retention indices and mass spectra. The lethal concentrations (LCs) of the EOs were determined between the third and fourth instar of A. aegypti. LC50 was determined by probit analysis using mortality rates of bioassays. All essential oils tested showed insecticidal activity. The following values were obtained for C. flexuosus (LC50 = 17.1 ppm); C. sinensis (LC50 = 20.6 ppm); the mixture of L. alba and L. origanoides (LC50 = 40.1 ppm); L. alba (LC50 = 42.2 ppm); C. odorata (LC50 = 52.9 ppm); L. origanoides (LC50 = 53.3 ppm); S. glutinosa (LC50 = 65.7 ppm); T. lucida (LC50 = 66.2 ppm); E. citriodora (LC50 = 71.2 ppm); and C. citratus (LC50 = 123.3 ppm). The EO from C. flexuosus, with citral (geranial + neral) as main component, showed the highest larvicidal activity. PMID:24781026

  15. Value Encounters - Modeling and Analyzing Co-creation of Value

    NASA Astrophysics Data System (ADS)

    Weigand, Hans

    Recent marketing and management literature has introduced the concept of co-creation of value. Current value modeling approaches such as e3-value focus on the exchange of value rather than co-creation. In this paper, an extension to e3-value is proposed in the form of a “value encounter”. Value encounters are defined as interaction spaces where a group of actors meet and derive value by each one bringing in some of its own resources. They can be analyzed from multiple strategic perspectives, including knowledge management, social network management and operational management. Value encounter modeling can be instrumental in the context of service analysis and design.

  16. Recovery of uranium values

    DOEpatents

    Brown, K. B.; Crouse, Jr., D. J.; Moore, J. G.

    1959-03-10

    A liquid-liquid extraction method is presented for recovering uranium values from an aqueous acidic solution by means of certain high molecular weight amine fn the amine classes of primary, secondary, heterocyclic secondary, tertiary, or heterocyclic tertiary. The uranium bearing aqueous acidic solution is contacted with the selected anine dissolved in a nonpolar waterimmiscible organfc solvent such as kerosene. The uranium which is substantially completely extracted by the organic phase may be stripped therefrom by water, and recovered from the aqueous phase by treatment into ammonia to precipitate ammonium diuranate.

  17. Earned Value-Added

    NASA Technical Reports Server (NTRS)

    Jansen, Michael

    2005-01-01

    Earned value management [EVM] ...either you swear by it, or swear at it. Either way, there s no getting around the fact that EVM can be one of the most efficient and insightful methods of synthesizing cost, schedule, and technical status information into a single set of program health metrics. Is there a way of implementing EVM that allows a program to reap its early warning benefits while avoiding the pitfalls that make it infamous to its detractors? That s the question recently faced by the International Space Station [ISS] program.

  18. RECOVERY OF URANIUM VALUES

    DOEpatents

    Brown, K.B.; Crouse, D.J. Jr.; Moore, J.G.

    1959-03-10

    A liquid-liquid extraction method is presented for recovering uranium values from an aqueous acidic solution by means of certain high molecular weight amine in the amine classes of primary, secondary, heterocyclic secondary, tertiary, or heterocyclic tertiary. The uranium bearing aqueous acidic solution is contacted with the selected amine dissolved in a nonpolar water-immiscible organic solvent such as kerosene. The uranium which is substantially completely exiracted by the organic phase may be stripped therefrom by waters and recovered from the aqueous phase by treatment into ammonia to precipitate ammonium diuranate.

  19. Histopathological changes induced by paraquat on some tissues of gourami fish (Trichogaster trichopterus)

    PubMed Central

    Banaee, M.; Davoodi, M.H.; Zoheiri, F.

    2013-01-01

    Paraquat is a contact and non-selective herbicide which is used for controlling a wide range of terrestrial weeds and aquatic plants. A long-term contact with this xenobiotic can potentially lead to injuries in fishes as live non-target organisms. Therefore, the current study aimed to investigate the effect of sub-lethal toxicity of paraquat on the pathology of gill, liver, and spleen tissues in gourami fish (Trichogaster trichopterus). In this study, sub-lethal concentration is determined based on lethal concentration (LC50 : 7.16±0.69, 4.46±0.43, 2.19±0.27 and 1.41±0.17 mg/l of paraquat within 24, 48, 72 and 96 hours, respectively). The experiment was done with four varied concentrations of paraquat (0.0, 0.07, 0.15, and 0.3 mg/l equal 0.0%, 5%, 10% and 20% of nominal value of 96 h LC50) during 3 weeks. The exposed fish displayed erratic swimming and became lethargic. The changes in gills were characterized by hypertrophy, epithelial, epithelium increase of gill filament, edema and secondary gill lamella. The liver showed hypotrophy of liver cells, cloudy swelling and formation of cytoplasmic vacuoles in the liver tissue of fish treated with 0.15 and 0.3 mg/l concentrations of paraquat. Disorder in the ellipsoid cell and hemosiderin accumulation in melano-macrophage centers was observed in the spleen tissue of fish exposed to 0.15 and 0.3 mg/l of paraquat. PMID:26623309

  20. Triterpenoid Saponins from Clematis graveolens and Evaluation of their Insecticidal Activities.

    PubMed

    Rattan, Rajeev; Reddy, S G Eswara; Dolma, Shudh Kirti; Fozdar, Bharat Inder; Gautam, Veena; Sharma, Ritika; Sharma, Upendra

    2015-09-01

    A new hederagenin based triterpenoid saponin, clematograveolenoside A (1), along with three known saponins, tomentoside A (2), huzhangoside D (3) and clematoside S (4), were isolated from the roots and rhizomes of Clematis graveolens. The structure of new compound was elucidated on the basis of detailed analysis of chemical and spectroscopic data including 1D- and 2D NMR spectra. Compound 2 was found the most effective against aphid (Aphis craccivora) with an LC50 of 1.2 and 0.5 mg/mL after treatment for 72 and 96 h, respectively and was followed by compound 4 (LC50 = 2.3 and 1.9 mg/mL) and 1 (LC50 = 3.2 and 2.6 mg/mL). In case of termite (Coptotermis homii), compound 1 was found more toxic with an LC50 of 0.1 mg/L after 24 h of treatment followed by compound 2, 3 and 4 (LC50 = 0.1, 0.2 and 0.2 mg/mL, respectively).

  1. Volume to value.

    PubMed

    Leaver, William B

    2013-01-01

    Traditional fee-for-service medicine has put physicians on an unsustainable treadmill of volume that escalates healthcare costs regardless of the quality of care they provide. This article shares the experience of UnityPoint Health (formerly Iowa Health System) in designing and implementing patient-centered, physician-led, coordinated care as a building block for transforming the delivery system. Keys to the effort's success include aligning physicians, hospitals, and home care delivery in terms of organizational goals and having the ability to gather, analyze, and share data to manage population health. On April 16, 2013, Iowa Health System became UnityPoint Health, dedicated to transforming the delivery of care through a coordinated system that offers regional, organized systems of care in most of our markets in Iowa and Illinois. These capabilities allowed the system to enter into value-based accountable care organization contracts that cover more than 220,000 lives. The transition ultimately will lead to population health-driven approaches in which compensation will be based on the management of specific populations or chronic diseases over a specified period. As increased value from care coordination becomes clear, the external environment will demand this better system, and patients will expect it. PMID:23858985

  2. Value Differences among Gifted Adolescents.

    ERIC Educational Resources Information Center

    Colangelo, Nicholas; Parker, Marolyn

    1981-01-01

    Gifted high school students (N=58) responded to a values survey consisting of two sets of 18 values: instrumental values and terminal values. Results showed no differences by sex in value patterns, academic performance, and self-concept. Suggests that sex-role stereotyped expectations still persist for the gifted in school and society. (RC)

  3. Acute toxicity of acidity in larvae and adults of four stream salamander species (Plethodontidae).

    PubMed

    Green, Linda E; Peloquin, Jennifer E

    2008-11-01

    High levels of acid deposition have severely affected streamwater chemistry in the southern Appalachians. Plethodontid stream salamanders living in and around headwater streams rely on cutaneous respiration and are highly susceptible to changes in water quality. We examined the sensitivity to low pH conditions in four stream salamanders by monitoring the response to six pH treatments ranging from pH 2.75 to 6.5. To quantify acid tolerance, we determined median lethal concentrations (LC50) in 96-h laboratory bioassays. This is the first study to quantify the level of sensitivity of stream salamanders to acidic conditions, indicating that stream salamanders are acid tolerant compared with many other lotic organisms. We found that acid tolerance is a species-specific trait with intraspecific variation shaped by life stage and body size. Mortality occurred at pH levels less than 4.2. The acid sensitivity of Desmognathus quadramaculatus larvae (LC50 = pH 3.95) was highest compared to sensitivity of Eurycea cirrigera larvae (LC50 = 3.6), Gyrinophilus porphyriticus larvae (LC50 = 3.5), and Pseudotriton ruber larvae (LC50 = 3.5). Larval survival was lower than adult survival in low pH treatments for E. cirrigera (adult LC50 = 3.1) and D. quadramaculatus (adult LC50 = 3.5). Salamanders responded to sublethal exposure to acidity with lethargic movements and decreased swimming speed. These results suggest that episodic acid events that cause streamwater pH to drop near 4.2 may cause mortality or induce sublethal effects, such as slower swimming speed. Because salamander larvae are more sensitive to acidic conditions than adults, we recommend that population monitoring programs extend methodology to include reliable estimates of larval population sizes.

  4. The value of reputation.

    PubMed

    Pfeiffer, Thomas; Tran, Lily; Krumme, Coco; Rand, David G

    2012-11-01

    Reputation plays a central role in human societies. Empirical and theoretical work indicates that a good reputation is valuable in that it increases one's expected payoff in the future. Here, we explore a game that couples a repeated Prisoner's Dilemma (PD), in which participants can earn and can benefit from a good reputation, with a market in which reputation can be bought and sold. This game allows us to investigate how the trading of reputation affects cooperation in the PD, and how participants assess the value of having a good reputation. We find that depending on how the game is set up, trading can have a positive or a negative effect on the overall frequency of cooperation. Moreover, we show that the more valuable a good reputation is in the PD, the higher the price at which it is traded in the market. Our findings have important implications for the use of reputation systems in practice.

  5. Energy and American values

    SciTech Connect

    Barbour, I.; Brooks, H.; Lakoff, S.; Opie, J.

    1982-01-01

    A multi-disciplinary team consisting of an engineer, a political scientist, an historian, and a professor of religion and physics view the question of energy and values from each other's perspective. The result is a synthesis of the team's views on all aspects of energy technology and how it affects human life in general as well as the lives of different classes and specific groups in our society. It begins with an historic overview of the way an abundance of energy has shaped America's use of it. It continues by considering the energy debate as a conflict between Jeffersonians who believe in decentralized, appropriate technology and the centralized, efficient technology of Hamiltonians. The authors wrestle with regional and geographical differences in energy resources, environmental impacts, and ethical problems. 384 references.

  6. The value of reputation.

    PubMed

    Pfeiffer, Thomas; Tran, Lily; Krumme, Coco; Rand, David G

    2012-11-01

    Reputation plays a central role in human societies. Empirical and theoretical work indicates that a good reputation is valuable in that it increases one's expected payoff in the future. Here, we explore a game that couples a repeated Prisoner's Dilemma (PD), in which participants can earn and can benefit from a good reputation, with a market in which reputation can be bought and sold. This game allows us to investigate how the trading of reputation affects cooperation in the PD, and how participants assess the value of having a good reputation. We find that depending on how the game is set up, trading can have a positive or a negative effect on the overall frequency of cooperation. Moreover, we show that the more valuable a good reputation is in the PD, the higher the price at which it is traded in the market. Our findings have important implications for the use of reputation systems in practice. PMID:22718993

  7. The innovation value chain.

    PubMed

    Hansen, Morten T; Birkinshaw, Julian

    2007-06-01

    The challenges of coming up with fresh ideas and realizing profits from them are different for every company. One firm may excel at finding good ideas but may have weak systems for bringing them to market. Another organization may have a terrific process for funding and rolling out new products and services but a shortage of concepts to develop. In this article, Hansen and Birkinshaw caution executives against using the latest and greatest innovation approaches and tools without understanding the unique deficiencies in their companies' innovation systems. They offer a framework for evaluating innovation performance: the innovation value chain. It comprises the three main phases of innovation (idea generation, conversion, and diffusion) as well as the critical activities performed during those phases (looking for ideas inside your unit; looking for them in other units; looking for them externally; selecting ideas; funding them; and promoting and spreading ideas companywide). Using this framework, managers get an end-to-end view of their innovation efforts. They can pinpoint their weakest links and tailor innovation best practices appropriately to strengthen those links. Companies typically succumb to one of three broad "weakest-link" scenarios. They are idea poor, conversion poor, or diffusion poor. The article looks at the ways smart companies - including Intuit, P&G, Sara Lee, Shell, and Siemens- modify the best innovation practices and apply them to address those organizations' individual needs and flaws. The authors warn that adopting the chain-based view of innovation requires new measures of what can be delivered by each link in the chain. The approach also entails new roles for employees "external scouts" and "internal evangelists," for example. Indeed, in their search for new hires, companies should seek out those candidates who can help address particular weaknesses in the innovation value chain. PMID:17580654

  8. The innovation value chain.

    PubMed

    Hansen, Morten T; Birkinshaw, Julian

    2007-06-01

    The challenges of coming up with fresh ideas and realizing profits from them are different for every company. One firm may excel at finding good ideas but may have weak systems for bringing them to market. Another organization may have a terrific process for funding and rolling out new products and services but a shortage of concepts to develop. In this article, Hansen and Birkinshaw caution executives against using the latest and greatest innovation approaches and tools without understanding the unique deficiencies in their companies' innovation systems. They offer a framework for evaluating innovation performance: the innovation value chain. It comprises the three main phases of innovation (idea generation, conversion, and diffusion) as well as the critical activities performed during those phases (looking for ideas inside your unit; looking for them in other units; looking for them externally; selecting ideas; funding them; and promoting and spreading ideas companywide). Using this framework, managers get an end-to-end view of their innovation efforts. They can pinpoint their weakest links and tailor innovation best practices appropriately to strengthen those links. Companies typically succumb to one of three broad "weakest-link" scenarios. They are idea poor, conversion poor, or diffusion poor. The article looks at the ways smart companies - including Intuit, P&G, Sara Lee, Shell, and Siemens- modify the best innovation practices and apply them to address those organizations' individual needs and flaws. The authors warn that adopting the chain-based view of innovation requires new measures of what can be delivered by each link in the chain. The approach also entails new roles for employees "external scouts" and "internal evangelists," for example. Indeed, in their search for new hires, companies should seek out those candidates who can help address particular weaknesses in the innovation value chain.

  9. Copper accumulation and oxidative stress in the sea anemone, Aiptasia pallida, after waterborne copper exposure.

    PubMed

    Main, W P L; Ross, C; Bielmyer, G K

    2010-03-01

    Copper is a common marine pollutant yet its effects on symbiotic cnidarians are largely understudied. To further understand the impact of elevated copper concentrations on marine symbiotic organisms, toxicity tests were conducted using the model sea anemone, Aiptasia pallida, with and without its zooxanthellae symbiont. Symbiotic and aposymbiotic A. pallida were exposed to sublethal copper concentrations (0, 5, 15, and 50 microg/L) for 7d and copper accumulation, behavior, and the activity of the oxidative stress enzymes, superoxide dismutase (SOD), and catalase (CAT) were measured. Additionally, acute 96-h toxicity tests were conducted to determine LC(50) values of the organisms after copper exposure. Both symbiotic and aposymbiotic A. pallida rapidly accumulated copper in a time and dose dependent manner. However, higher copper concentrations accumulated in the aposymbiotic as compared to the symbiotic A. pallida. In response to the highest two copper exposures (15 and 50 microg/L) symbiotic A. pallida upregulated CAT activity to combat the damaging effects of hydrogen peroxide. Contrary to these results, SOD activity significantly decreased during the highest copper exposure, when compared to controls. CAT activity was not detected and SOD was substantially (>10 fold) reduced in aposymbiotic A. pallida, suggesting that the zooxanthellae are associated with the oxidative stress response. Copper exposure as low as 5 microg/L caused tentacle retraction and increased mucus production in both symbiotic and aposymbiotic anemones. The LC(50) values for symbiotic and aposymbiotic A. pallida exposed to copper for 96 h were 148 microg/L (95% confidence interval=126.4, 173.8) and 206 microg/L (95% confidence interval=175.2, 242.2), respectively. Understanding the varying responses of symbiotic and aposymbiotic A. pallida to copper stress may advance our comprehension of the functional roles of zooxanthellae and host. Although the mechanism of copper toxicity has not been

  10. Winter third- to fourth-instar larvae of Chironomus plumosus as bioassay tools for assessment of acute toxicity of metals and their binary combinations.

    PubMed

    Fargasová, A

    2001-01-01

    The ecotoxicological effect expressed as mortality of four metal ions (Cd, Cu, Zn, Al) and their associations on winter third- to fourth-instar larvae of Chironomus plumosus was determined. The effect of individual metals was introduced as acute toxicological effect and expressed as LC(50) and LC95 values with 95% intervals of confidence. On the basis of the LC50 values the toxicity of metals after 96 h treatment was ranked Cu>Cd>Zn>Al. Copper was at least 100 times more toxic than other metals tested. When the acute toxic effect of metal pairs was observed, in general, deleterious effects were directly proportional to metal concentrations. The toxicity of metals in combinations was different from that of individual metals, because of either antagonism or synergism. From the results obtained it can be concluded that when in metal pairs in which the original metal (the metal for which the interaction was determined) is at the lower concentration (Cd 10 mg x L(-1), Zn 25 mg x L(-1), Al 25 mg x L(-1), Cu 0.1 mg x L(-1)), the prevailing interaction is synergism (mortality was higher for metal combinations than for individual metals). Except for an overadditive effect (synergism), additivity was also confirmed in some cases (Al25+Cd10; Al25+Cd25; Al25+Cu0.1; Cu0.1+Cd10; Cu0.1+Cd25; Cu0.1+Al50). Synergism, in combinations in which the original metal is at the higher concentration (Cd 25 mg x L(-1), Zn 50 mg x L(-1), Al 50 mg x L(-1), Cu 1.0 mg x L(-1)), was observed only for the pairs Zn50+Al25 and Zn50+Cu1.0. Reciprocal additivity was observed after 96 h of treatment only for the combination Zn50+Al50. For all other binary combinations in which the original metal was at the higher concentration, an antagonistic effect was confirmed.

  11. Acute Toxic Effects of the Herbicide Formulation Focus(®) Ultra on Embryos and Larvae of the Moroccan Painted Frog, Discoglossus scovazzi.

    PubMed

    Wagner, Norman; Lötters, Stefan; Veith, Michael; Viertel, Bruno

    2015-11-01

    For regulatory and scientific purposes, there is a need to understand the sensitivity of a wider variety of wild species of amphibians and the sensitivities within their life stages to chemicals of widespread use such as herbicides. We investigated the acute toxic effects of the herbicide formulation Focus Ultra [with the active ingredient (a.i.) cycloxydim plus solvent naphtha and sodium dioctylsulphosuccinate as added substances] on embryos and early stage larvae of the Moroccan painted frog (Discoglossus scovazzi). Different clinical signs (twitching, convulsion, and narcosis) occurred at 40 and 80 mg/L in embryos (4 and 8 mg a.i./L) and narcotic effects (total immobilization or irregular escape responses) at 10, 15, and 20 mg/L in larvae (1, 1.5, and 2 mg a.i./L). Growth inhibition (total length), starting at 20 mg/L in embryos and 2.5 mg/L in larvae (2 and 0.25 mg a.i./L, respectively) was understood as sign of toxicity (retardation) and not as sign of teratogenicity. However, the connection to teratogenesis remained unclear though total length reduction occurred at concentrations <20 % of the 96-h LC50 value and at a minimum concentration that inhibits growth of only 17 % of the 96-h LC50 value. Starting at 20 mg/L, mortality in embryos significantly increased and at 15 mg/L in early larvae (2 and 1.5 mg a.i./L, respectively). Mortality of larvae was enhanced during the first 24 h of exposure to 15 and 20 mg/L (1.5 and 2 mg a.i./L). Morphology of the embryos remained unobtrusive. In contrary, axial malformations significantly increased in the early larvae starting at 10 mg/L (1 mg a.i./L), a concentration free of lethal effects. In all considered end points, larvae were significantly more sensitive than embryos, probably because of developmental and physiological properties or different exposure and bioavailability of the compound. Focus Ultra induced comparable lethal and immobilization effects in D. scovazzi as it does to standard test

  12. The forecaster's added value

    NASA Astrophysics Data System (ADS)

    Turco, M.; Milelli, M.

    2009-09-01

    To the authors' knowledge there are relatively few studies that try to answer this topic: "Are humans able to add value to computer-generated forecasts and warnings ?". Moreover, the answers are not always positive. In particular some postprocessing method is competitive or superior to human forecast (see for instance Baars et al., 2005, Charba et al., 2002, Doswell C., 2003, Roebber et al., 1996, Sanders F., 1986). Within the alert system of ARPA Piemonte it is possible to study in an objective manner if the human forecaster is able to add value with respect to computer-generated forecasts. Every day the meteorology group of the Centro Funzionale of Regione Piemonte produces the HQPF (Human QPF) in terms of an areal average for each of the 13 regional warning areas, which have been created according to meteo-hydrological criteria. This allows the decision makers to produce an evaluation of the expected effects by comparing these HQPFs with predefined rainfall thresholds. Another important ingredient in this study is the very dense non-GTS network of rain gauges available that makes possible a high resolution verification. In this context the most useful verification approach is the measure of the QPF and HQPF skills by first converting precipitation expressed as continuous amounts into ‘‘exceedance'' categories (yes-no statements indicating whether precipitation equals or exceeds selected thresholds) and then computing the performances for each threshold. In particular in this work we compare the performances of the latest three years of QPF derived from two meteorological models COSMO-I7 (the Italian version of the COSMO Model, a mesoscale model developed in the framework of the COSMO Consortium) and IFS (the ECMWF global model) with the HQPF. In this analysis it is possible to introduce the hypothesis test developed by Hamill (1999), in which a confidence interval is calculated with the bootstrap method in order to establish the real difference between the

  13. An Introduction to Value Analysis.

    ERIC Educational Resources Information Center

    Takacs, Kalman

    1983-01-01

    Emphasizes consciousness as a quality which differentiates a human being from other living organisms. Excerpts various perspectives that are value-analyzed to illustrate two assumptions: (1) thinking leads to valuing and values and (2) all psychological perspectives are based upon some value system which can be identified. (JAC)

  14. Work Values and Career Education.

    ERIC Educational Resources Information Center

    Mongo, Celestine

    1978-01-01

    As career education calls for business educators to be concerned with developing students' work values as well as teaching skills, school experiences should be structured to influence work values development. The author discusses the nature of values, group differences, strategies for personal value sharing, industry-school interactions, and…

  15. Values taught, values learned, attitude and performance in mathematics

    NASA Astrophysics Data System (ADS)

    Limbaco, K. S. A.

    2015-03-01

    The purpose of the study was to identify, describe and find the relationship among values taught, values learned, attitude and performance in mathematics. The researcher used descriptive-correlational method of research to gather information and to describe the nature of situation. The following instruments were used in this study: Math Attitude Inventory, Inventory of Values Taught and Learned which were content validated by experts in the field of Mathematics, Values and Education. Generally, most of the values were taught by the teachers. All of the values were learned by the students. The following got the highest mean ratings for values taught: moral strength, sharing, charity, valuing life, love of God, truth and honesty, reason, alternativism and articulation. The following got highest mean ratings for values learned: patience/tolerance, sharing, charity, valuing life, faith, love of God, truth and honesty, analogical thinking, confidence and individual liberty. Majority of the respondents have moderately positive attitude towards mathematics. Positive statements in the Mathematics Attitude Inventory are "Generally true" while negative statements are "Neutral." In conclusion, values were taught by mathematics teacher, thus, learned by the students. Therefore, mathematics is very much related to life. Values can be learned and strengthened through mathematics; there is a significant relationship between values taught by the teachers and values learned by the students and attitude towards mathematics and performance in mathematics; values taught does not affect attitude towards mathematics and performance in mathematics. A student may have a positive attitude towards mathematics or have an exemplary performance in mathematics even if the mathematics teacher did not teach values; values learned does not affect attitude towards mathematics and performance in mathematics. A student may have a positive attitude towards mathematics or have an exemplary performance

  16. Neurobiology of value integration: when value impacts valuation.

    PubMed

    Park, Soyoung Q; Kahnt, Thorsten; Rieskamp, Jörg; Heekeren, Hauke R

    2011-06-22

    Everyday choice options have advantages (positive values) and disadvantages (negative values) that need to be integrated into an overall subjective value. For decades, economic models have assumed that when a person evaluates a choice option, different values contribute independently to the overall subjective value of the option. However, human choice behavior often violates this assumption, suggesting interactions between values. To investigate how qualitatively different advantages and disadvantages are integrated into an overall subjective value, we measured the brain activity of human subjects using fMRI while they were accepting or rejecting choice options that were combinations of monetary reward and physical pain. We compared different subjective value models on behavioral and neural data. These models all made similar predictions of choice behavior, suggesting that behavioral data alone are not sufficient to uncover the underlying integration mechanism. Strikingly, a direct model comparison on brain data decisively demonstrated that interactive value integration (where values interact and affect overall valuation) predicts neural activity in value-sensitive brain regions significantly better than the independent mechanism. Furthermore, effective connectivity analyses revealed that value-dependent changes in valuation are associated with modulations in subgenual anterior cingulate cortex-amygdala coupling. These results provide novel insights into the neurobiological underpinnings of human decision making involving the integration of different values.

  17. Values in a Science of Social Work: Values-Informed Research and Research-Informed Values

    ERIC Educational Resources Information Center

    Longhofer, Jeffrey; Floersch, Jerry

    2014-01-01

    While social work must be evaluative in relation to its diverse areas of practice and research (i.e., values-informed research), the purpose of this article is to propose that values are within the scope of research and therefore research on practice should make values a legitimate object of investigation (i.e., research-informed values). In this…

  18. Section III: Examining American Values: Value Choices Since Revolutionary Times

    ERIC Educational Resources Information Center

    Social Education, 1974

    1974-01-01

    The statements of Erik Erikson and Urie Bronfenbrenner on American values are followed by a values clarification exercise and an activity based on biographical sketches of five Americans who lived before and after the American Revolution. (KM)

  19. The value ground of nursing.

    PubMed

    Snellman, Ingrid; Gedda, Kersti M

    2012-11-01

    The aim of this literature study was to suggest a value ground for nursing anchored in two ethical principles: the principle of human value and the right to experience a meaningful life. Previous nursing research between the years 2000 and 2009 was analysed. Presented values suggested in this value ground are thus in line with the nursing context and science of today. Statements within ethical literature have been used in order to formulate arguments aimed at supporting the values that were found in the study. In the literature study six values were found: trust, nearness, sympathy, support, knowledge and responsibility. These values hold equal status and are not presented in hierarchical order. They vary due to the persons involved, nursing situations and cultural surroundings, but have the common requirement of being non-excluding. In order to implement the values within the value ground, two prerequisites are discussed and claimed as essential: ethical dialogue and a caring encounter between care provider and patients.

  20. Integrating Value and Utility Concepts into a Value Decomposition Model for Value-Based Software Engineering

    NASA Astrophysics Data System (ADS)

    Rönkkö, Mikko; Frühwirth, Christian; Biffl, Stefan

    Value-based software engineering (VBSE) is an emerging stream of research that addresses the value considerations of software and extends the traditional scope of software engineering from technical issues to business-relevant decision problems. While the concept of value in VBSE relies on the well-established economic value concept, the exact definition for this key concept within VBSE domain is still not well defined or agreed upon. We argue the discourse on value can significantly benefit from drawing from research in management, particularly software business. In this paper, we present three aspects of software: as a technology, as a design, and as an artifact. Furthermore, we divide the value concept into three components that are relevant for software product development companies and their customers: intrinsic value, externalities and option value. Finally, we propose a value decomposition matrix based on technology views and value components.

  1. Teacher Values and Relationship: Factors in Values Education

    ERIC Educational Resources Information Center

    Brady, Laurie

    2011-01-01

    Intrigued by the notion that effective teaching is as much about relationship as it is about "technical" proficiency, the author examines the values of teachers that inform classroom relationships, and poses the question as to whether there are particular teacher values that are necessary for quality values education. This question is addressed by…

  2. [Value-Added--Adding Economic Value in the Food Industry].

    ERIC Educational Resources Information Center

    Welch, Mary A., Ed.

    1989-01-01

    This booklet focuses on the economic concept of "value added" to goods and services. A student activity worksheet illustrates how the steps involved in processing food are examples of the concept of value added. The booklet further links food processing to the idea of value added to the Gross National Product (GNP). Discussion questions, a student…

  3. Universal values of Canadian astronauts

    NASA Astrophysics Data System (ADS)

    Brcic, Jelena; Della-Rossa, Irina

    2012-11-01

    Values are desirable, trans-situational goals, varying in importance, that guide behavior. Research has demonstrated that universal values may alter in importance as a result of major life events. The present study examines the effect of spaceflight and the demands of astronauts' job position as life circumstances that affect value priorities. We employed thematic content analysis for references to Schwartz's well-established value markers in narratives (media interviews, journals, and pre-flight interviews) of seven Canadian astronauts and compared the results to the values of National Aeronautics and Space Administration (NASA) and Russian Space Agency (RKA) astronauts. Space flight did alter the level of importance of Canadian astronauts' values. We found a U-shaped pattern for the values of Achievement and Tradition before, during, and after flight, and a linear decrease in the value of Stimulation. The most frequently mentioned values were Achievement, Universalism, Security, and Self-Direction. Achievement and Self Direction are also within the top 4 values of all other astronauts; however, Universalism was significantly higher among the Canadian astronauts. Within the value hierarchy of Canadian astronauts, Security was the third most frequently mentioned value, while it is in seventh place for all other astronauts. Interestingly, the most often mentioned value marker (sub-category) in this category was Patriotism. The findings have important implications in understanding multi-national crew relations during training, flight, and reintegration into society.

  4. The Value of Imaging Part II: Value beyond Image Interpretation.

    PubMed

    Duong, Phuong-Anh T; Pastel, David A; Sadigh, Gelareh; Ballard, David; Sullivan, Joseph C; Bresnahan, Brian; Buch, Karen; Duszak, Richard

    2016-01-01

    Although image interpretation is an essential part of radiologists' value, there are other ways in which we contribute to patient care. Part II of the value of imaging series reviews current initiatives that demonstrate value beyond the image interpretation. Standardizing processes, reducing the radiation dose of our examinations, clarifying written reports, improving communications with patients and providers, and promoting appropriate imaging through decision support are all ways we can provide safer, more consistent, and higher quality care. As payers and policy makers push to drive value, research that demonstrates the value of these endeavors, or lack thereof, will become increasingly sought after and supported.

  5. The Value of Imaging Part II: Value beyond Image Interpretation.

    PubMed

    Duong, Phuong-Anh T; Pastel, David A; Sadigh, Gelareh; Ballard, David; Sullivan, Joseph C; Bresnahan, Brian; Buch, Karen; Duszak, Richard

    2016-01-01

    Although image interpretation is an essential part of radiologists' value, there are other ways in which we contribute to patient care. Part II of the value of imaging series reviews current initiatives that demonstrate value beyond the image interpretation. Standardizing processes, reducing the radiation dose of our examinations, clarifying written reports, improving communications with patients and providers, and promoting appropriate imaging through decision support are all ways we can provide safer, more consistent, and higher quality care. As payers and policy makers push to drive value, research that demonstrates the value of these endeavors, or lack thereof, will become increasingly sought after and supported. PMID:26683509

  6. Neurocognitive mechanisms underlying value-based decision-making: from core values to economic value

    PubMed Central

    Brosch, Tobias; Sander, David

    2013-01-01

    Value plays a central role in practically every aspect of human life that requires a decision: whether we choose between different consumer goods, whether we decide which person we marry or which political candidate gets our vote, we choose the option that has more value to us. Over the last decade, neuroeconomic research has mapped the neural substrates of economic value, revealing that activation in brain regions such as ventromedial prefrontal cortex (VMPFC), ventral striatum or posterior cingulate cortex reflects how much an individual values an option and which of several options he/she will choose. However, while great progress has been made exploring the mechanisms underlying concrete decisions, neuroeconomic research has been less concerned with the questions of why people value what they value, and why different people value different things. Social psychologists and sociologists have long been interested in core values, motivational constructs that are intrinsically linked to the self-schema and are used to guide actions and decisions across different situations and different time points. Core value may thus be an important determinant of individual differences in economic value computation and decision-making. Based on a review of recent neuroimaging studies investigating the neural representation of core values and their interactions with neural systems representing economic value, we outline a common framework that integrates the core value concept and neuroeconomic research on value-based decision-making. PMID:23898252

  7. Effect of water pH on the toxicity of 2,4,5-trichlorophenol to four species of freshwater animals

    SciTech Connect

    Brooke, L.T.; Markee, T.; Vande Venter, F.; Spehar, R.; Erickson, R.

    1994-12-31

    2,4,5-Trichlorophenol (TCP) is a weak acid with a pH of approximately 7.2 which is expected to have a significant effect upon its toxicity. Lumbriculus variegatus, Oncorhynchus mykiss, Pimephales promelas, and Hyalella azteca were exposed to TCP in 96 h flow-through toxicity tests. For the first two species, simultaneous tests were conducted at three pH values (7.0, 7.8, 8.6). The other two species were tested at six pH values conducted in two sets of three simultaneous tests (6.2, 7.4, 8.6 and 6.8, 8.0, 9.2). All species tested showed decreased sensitivity to TCP with increased pH of the water. Over the pH range tested, LC50s for L. variegatus varied by about 5-fold, for P. promelas by 12-fold, for H. azteca by 10-fold, and for O. mykiss by 1.5-fold. The effects of pH on TCP toxicity to P. promelas was also tested in 30 day chronic tests at pH 7.0, 7.8 and 8.6. Survival in these tests was affected by pH similarly to the acute tests. Growth also was less severely affected at higher pH.

  8. Sublethal propoxur toxicity to juvenile common carp (Cyprinus carpio L., 1758): biochemical, hematological, histopathological, and genotoxicity effects.

    PubMed

    Gül, Ali; Benli, A Çağlan Karasu; Ayhan, Ayşen; Memmi, Burcu Koçak; Selvi, Mahmut; Sepici-Dinçel, Aylin; Cakiroğullari, Gül Çelik; Erkoç, Figen

    2012-09-01

    The sublethal toxicological and genotoxic potential of propoxur, a widely used carbamate insecticide against household pests, in veterinary medicine, and in public health, was evaluated on carp as a model species (Cyprinus carpio L., 1758) using the erythrocyte micronucleus test. Based on the 96-h lethal concentration, 50% (LC50) data from the U.S. Environmental Protection Agency ECOTOX Database (10 mg/L), a sublethal exposure concentration of 5 mg/L was used under static bioassay laboratory conditions. Histopathological evaluation showed no significant changes in spleen, intestine, muscle, or skin tissues. However, the following conditions were recorded: hyperemia, branchitis in primary lamella, and telangiectasis, hyperplasia, fusion, epithelial lifting, and epithelial desquamation in secondary lamella of gill tissues; hemorrhage, destruction, prenephritis, and inflammation and desquamation in the tubules; edema in the kidney; passive hyperemia, albumin, and hydropic degeneration in the liver; and hyperemia, chromatolysis, and glial proliferation in brain tissues. No statistically significant increases in micronuclei frequencies were found. Hematological parameters showed decreased hematocrit values and mean corpuscular volume values, as well as increased erythrocyte and leukocyte counts compared with the control group (p < 0.01). Plasma glucose, cholesterol, triglycerides, phosphorus, sodium, total plasma protein, chloride, and aspartate aminotransferase levels were increased (p < 0.01). Only plasma calcium and potassium levels decreased in the experimental group. Propoxur has an ecotoxicological potential on fish, a nontarget organism.

  9. Acute toxicity of butachlor and atrazine to freshwater green alga Scenedesmus obliquus and cladoceran Daphnia carinata.

    PubMed

    He, Hongzhi; Yu, Jing; Chen, Guikui; Li, Wenyang; He, Jinbo; Li, Huashou

    2012-06-01

    Both single and joint toxicity of atrazine and butachlor to freshwater green alga Scenedesmus obliquus and cladoceran Daphnia carinata isolated from South China were investigated in the present study. The 96 h-EC(50) values of atrazine and butachlor to S. obliquus were 0.0147 and 2.31 mg L(-1), while the 48 h-LC(50) values to D. carinata were 60.6 and 3.40 mg L(-1), respectively. These results suggest that atrazine could be highly toxic to S. obliquus and slightly toxic to D. carinata, while butachlor exhibits moderate toxicity to both organisms. The additive indexes of atrazine and butachlor mixtures were -2.68 (-3.02 to -2.32) to S. obliquus and 0.054 (-0.025 to 0.238) to D. carinata, respectively. Therefore, the joint action of two herbicides was significant antagonism to S. obliquus, while significant synergism was not shown to D. carinata. Moreover, significant linear correlation between the natural logarithm of herbicide concentrations and growth rates of alga S. obliquus was observed. Taken together, it is the first study reporting the toxicity endpoints for mixture of atrazine and butachlor against S. obliquus and D. carinata isolated from south China. The present results would be helpful to provide data to assess the ecological risk of both herbicides to aquatic organisms.

  10. Toxic effects of benzo[a]pyrene (Bap) and Aroclor1254 on embryogenesis, larval growth, survival and metamorphosis of the bivalve Meretrix meretrix.

    PubMed

    Wang, Qing; Yang, Hongsheng; Liu, Baozhong; Wang, Xiaoyu

    2012-08-01

    To assess the potential toxicity of polycyclic aromatic hydrocarbons and polychlorinated biphenyls on the early development of Meretrix meretrix, the effects of benzo[a]pyrene (Bap) and Aroclor1254 on embryogenesis and larval development were investigated using static laboratory toxicity tests at nominal concentrations of 6.25-1,600 μg/L. Even at 1,600 μg/L, Bap and Aroclor1254 only caused minor reductions in embryo development rates. The 96 h LC(50) values for D-shaped larvae were 156 μg/L for Bap and 132 μg/L for Aroclor1254, respectively. The most sensitive toxicity endpoint in this study was metamorphosis, with an EC(50) value of 20 μg/L for Bap and 35 μg/L for Aroclor1254. Aroclor1254 was more toxic than Bap to embryos and larvae. Our results indicate that Bap and Aroclor1254 do not show extreme toxicity to M. meretrix embryos and larvae. These data provide information for evaluating the toxicity of Bap and Aroclor1254 on bivalve embryos, especially over the entire larval stages.

  11. [Acute toxicity of three typical pollutants to aquatic organisms and their water quality criteria].

    PubMed

    Jiang, Dong-Sheng; Shi, Xiao-Rong; Cui, Yi-Bin; Li, Mei

    2014-01-01

    Two species of microalgae Chlorella pyrenoidosa, Scenedesmus obliqnus and a red worm Chironomidae larvae were selected as test organisms in determining the acute toxicity effects of Cr (VI), 2,4,6-trichlorophenol and nitrobenzene. The results were able to provide more information on water quality criteria and more data on their toxicity to indigenous aquatic organisms in China. The 96 h-EC50 values of Cr (VI), TCP and nitrobenzene on C. pyrenoidosa were 1.34 mg x L(-1, 4.55 mg x L(-1) and 86.58 mg x L(-1), respectively, while those of S. obliqnus were 19.52 mg x L(-1), 3.71 mg x L(-1) and 74.15 mg x L(-1), respectively. The mortality of C. larvae was 15% when the concentration of Cr(VI) was increased to 1,500 mg x L(-1). The 48 h-LC50 values of TCP and nitrobenzene on C. larvae were 9.29 mg x L(-1) and 98.34 mg x L(-1), respectively. These results indicated that Cr( VI) showed higher toxicity to C. pyrenoidosa, while only moderate toxicity to S. obliqnus; TCP had higher toxicity to C. pyrenoidosa and S. oblignus; while nitrobenzene was only moderately toxic to both species of microalgae. The toxicity among the three pollutants to C. larvae was in the order of TCP > nitrobenzene > Cr (VI). PMID:24720216

  12. Biochemical and genotoxic response of naphthalene to fingerlings of milkfish Chanos chanos.

    PubMed

    Palanikumar, L; Kumaraguru, A K; Ramakritinan, C M

    2013-09-01

    The present study investigated the acute toxicity, sub-lethal toxicity and biochemical response of naphthalene in fingerlings of milkfish Chanos chanos. The 96 h acute toxicity LC50 values for C. chanos exposed to naphthalene was 5.18 μg l(-1). The estimated no observed effect concentration and lowest observed effect concentration values for naphthalene in C. chanos were 0.42 and 0.69 μg l(-1) respectively for 30 days. The estimated maximum allowable toxicant concentration for naphthalene was 0.53 μg l(-1). Biochemical enzyme markers such as lipid peroxidation, catalase, glutathione S transferase and reduced glutathione were measured in gills and liver tissues of C. chanos exposed to sub-lethal concentrations of naphthalene. Fluctuation in lipid peroxidation and catalase level suggests that naphthalene concentrations play a vital role in induction of oxidative stress in fish. Induction of reduced glutathione level and inhibition of glutathione S-transferase level was observed in naphthalene exposed C. chanos suggesting that there may be enhanced oxidative damage due to free radicals. Increasing concentration increases in number of nuclear abnormalities. The formation of micronuclei and binucleated micronuclei induction by naphthalene confirm its genotoxic potential. The highest levels of DNA damage (% tail length) were observed at 1.24 μg l(-1) of naphthalene. The study suggests that biochemical enzymes, nuclear abnormalities and DNA damage index can serve as a biological marker for naphthalene contamination.

  13. American Values through Russian Eyes.

    ERIC Educational Resources Information Center

    Zatsepina, Olga; Rodriguez, Julio

    This paper discusses impressions held by Moscow State University (Russia) students about American values. In class discussions and written assignments, students were asked to comment on thirteen values, giving their perceptions of American attitudes in each case. The values included: personal control over the environment; change; time and its…

  14. Values Education: Interdisciplinary Curriculum Strand.

    ERIC Educational Resources Information Center

    Utah State Office of Education, Salt Lake City. Div. of Curriculum and Instruction.

    The instructional objectives of values education to be taught in the K-12 Utah public schools are outlined and cross-referenced to each subject area in the curriculum. It is the responsibility of the schools to help students clarify perceptions and values with respect to self and society. The major categories of values education goals are: rights…

  15. Student Development and Values Education.

    ERIC Educational Resources Information Center

    Dalton, John D., Comp.

    1982-01-01

    In five articles explores the value development of college students. Surveyed student personnel administrators to investigate ethical issues and values in student development and educational approaches to values development. Presents an approach to student ethical development. Discusses a rationale for developmental education considering…

  16. The Logic of Values Clarification

    ERIC Educational Resources Information Center

    Kazepides, A. C.

    1977-01-01

    Traces the origin of the Values Clarification movement in education in Carl Roger's clien-centered therapy and exposes its unwarranted extreme ethical stance. Examines a model episode of values clarification and shows how the theoretical confusions of the Values Clarification proponents are reflected in their actual teaching strategies. (Editor/RK)

  17. Teaching the Value of Science

    ERIC Educational Resources Information Center

    Shumow, Lee; Schmidt, Jennifer A.

    2015-01-01

    Why and under what conditions might students value their science learning? To find out, the authors observed approximately 400 science classes. They found that although several teachers were amazingly adept at regularly promoting the value of science, many others missed out on important opportunities to promote the value of science. The authors…

  18. Identifying and Clarifying Organizational Values.

    ERIC Educational Resources Information Center

    Seevers, Brenda S.

    2000-01-01

    Of the 14 organizational values ranked by a majority of 146 New Mexico Cooperative Extension educators as extremely valued, 9 were extremely evident in organizational policies and procedures. A values audit such as this forms an important initial step in strategic planning. (SK)

  19. Integrating values in job descriptions.

    PubMed

    Craig, R P

    1987-12-01

    The Mission Services Division of the Sisters of Charity of the Incarnate Word Health Care Corporation, Houston, has established training sessions to help various facilities develop criteria-based job descriptions that integrate values. A major problem with traditional job descriptions is that they do not contain enough information for value integration to occur. Each facet of the job description--the responsibility statement, the task statement, and the standard--can integrate the facilities' values in explicit and implicit ways. Such integration reduces the possibility of a supervisor arbitrarily defining the qualitative aspects of how an employee performs the job and provides a better method for evaluating the quality of the employee's performance. The first step in value integration is to identify the organization's values. Next, illustrative behaviors are identified to emphasize value integration in both activity-based task statements and results-based standards. The final step is to integrate the values in the job description, which makes the value operational and bridges the gap between commitment to values and behavior that exemplifies those values. Although values cannot be measured as objectively as the successful accomplishment of a procedure with a specified method of measurement, evaluation of values is not fruitless. When the employee and supervisor agree on specific qualitative aspects of patient care or other tasks, the consistency of the qualitative aspects of the job can be evaluated.

  20. 78 FR 53380 - Value Engineering

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-29

    ... TRANSPORTATION Federal Highway Administration 23 CFR Part 627 RIN 2125-AF64 Value Engineering AGENCY: Federal... Making (NPRM); request for comments. SUMMARY: The FHWA proposes to update the existing value engineering... Leuderalbert, Value Engineering and Utilities Program Manager, FHWA Office of Program Administration,...

  1. Principals' Values in School Administration

    ERIC Educational Resources Information Center

    Aslanargun, Engin

    2012-01-01

    School administration is value driven area depending on the emotions, cultures, and human values as well as technique and structure. Over the long years, educational administration throughout the world have experienced the influence of logical positivism that is based on rational techniques more than philosophical consideration, ignored values and…

  2. Negativity bias and basic values.

    PubMed

    Schwartz, Shalom H

    2014-06-01

    Basic values explain more variance in political attitudes and preferences than other personality and sociodemographic variables. The values most relevant to the political domain are those likely to reflect the degree of negativity bias. Value conflicts that represent negativity bias clarify differences between what worries conservatives and liberals and suggest that relations between ideology and negativity bias are linear. PMID:24970450

  3. Teaching Values through Children's Literature.

    ERIC Educational Resources Information Center

    Ramp, Ellen; Ridout, Susan Ramp

    Suggesting that reading teachers can use children's literature as a vehicle for teaching values, this paper presents an annotated bibliography of children's literature and lesson plans that can help teach the values of honesty, respect, responsibility, compassion, self-discipline, perseverance, and giving. After a brief description of the values,…

  4. Sex Differences in Work Values.

    ERIC Educational Resources Information Center

    Beutell, Nicholas J.; Brenner, O. C.

    1986-01-01

    Investigated sex differences in work values. Significant sex differences were found on 18 of 25 values with women rating 12 of these values higher than men. However, despite item differences, there was a clear trend toward similarity in the importance of work outcomes among women and men. (Author/BL)

  5. Valuing Your Child Care Business.

    ERIC Educational Resources Information Center

    Linsmeier, Dave; Richards, Dick; Routzong, Ed

    2003-01-01

    Offers guidelines for putting a monetary value on a child care business. Discusses reasons for valuing the business, types of valuations (book, liquidation, and fair market), fair market valuation formulas, the corporate valuation, valuing assets included in a sale, and using experts. Also offers several tips for selling a child care business. (EV)

  6. Make your values mean something.

    PubMed

    Lencioni, Patrick M

    2002-07-01

    Take a look at this list of corporate values: Communication. Respect. Integrity. Excellence. They sound pretty good, don't they? Maybe they even resemble your own company's values. If so, you should be nervous. These are the corporate values of Enron, as claimed in its 2000 annual report. And they're absolutely meaningless. Indeed, most values statements, says the author, are bland, toothless, or just plain dishonest. And far from being harmless, as some executives assume, they're often highly destructive. Empty values statements create cynical and dispirited employees and undermine managerial credibility. But coming up with strong values--and sticking to them--isn't easy. Organizations that want their values statements to really mean something should follow four imperatives. First, understand the different types of values: core, aspirational, permission-to-play, and accidental. Confusing them with one another can bewilder employees and make management seem out of touch. Second, be aggressively authentic. Too many companies view a values initiative in the same way they view a marketing launch: a onetime event measured by the initial attention it receives, not by its content. Third, own the process. Values initiatives are about imposing a set of fundamental, strategically sound beliefs on a broad group of people. That's why the best values efforts are driven by small teams. Finally, weave core values into everything. It's not enough to hang your values statement on the wall; it must be integrated into every employee-related process--hiring methods, performance management systems, even dismissal policies. Living by stated corporate values is difficult. But the benefits of doing so can be profound; so can the damage from adopting a hollow set of corporate values.

  7. Full-life chronic toxicity of sodium salts to the mayfly Neocloeon triangulifer in tests with laboratory cultured food.

    PubMed

    Soucek, David J; Dickinson, Amy

    2015-09-01

    Although insects occur in nearly all freshwater ecosystems, few sensitive insect models exist for use in determining the toxicity of contaminants. The objectives of the present study were to adapt previously developed culturing and toxicity testing methods for the mayfly Neocloeon triangulifer (Ephemeroptera: Baetidae), and to further develop a method for chronic toxicity tests spanning organism ages of less than 24 h post hatch to adult emergence, using a laboratory cultured diatom diet. The authors conducted 96-h fed acute tests and full-life chronic toxicity tests with sodium chloride, sodium nitrate, and sodium sulfate. The authors generated 96-h median lethal concentrations (LC50s) of 1062 mg Cl/L (mean of 3 tests), 179 mg N-NO3 /L, and 1227 mg SO4 /L. Acute to chronic ratios ranged from 2.1 to 6.4 for chloride, 2.5 to 5.1 for nitrate, and 2.3 to 8.5 for sulfate. The endpoints related to survival and development time were consistently the most sensitive in the tests. The chronic values generated for chloride were in the same range as those generated by others using natural foods. Furthermore, our weight-versus-fecundity plots were similar to those previously published using the food culturing method on which the present authors' method was based, indicating good potential for standardization. The authors believe that the continued use of this sensitive mayfly species in laboratory studies will help to close the gap in understanding between standard laboratory toxicity test results and field-based observations of community impairment.

  8. Effects of six chemical deicers on larval wood frogs (Rana sylvatica).

    PubMed

    Harless, Meagan L; Huckins, Casey J; Grant, Jacqualine B; Pypker, Thomas G

    2011-07-01

    Widespread and intensive application of road deicers, primarily road salt (NaCl), in North America threatens water quality and the health of freshwater ecosystems. Intensive use of NaCl can be harmful to sensitive members of freshwater ecosystems such as amphibians. Detection of negative effects of NaCl application has prompted the search for alternative chemical deicers with lower environmental impacts. We conducted a series of 96-h acute toxicity tests to determine the negative sensitivity of larval wood frogs (Rana [Lithobates] sylvatica) to six deicing chemicals: urea (CH(4) N(2) O), sodium chloride (NaCl), magnesium chloride (MgCl(2) ), potassium acetate (CH(3) COOK), calcium chloride (CaCl(2) ), and calcium magnesium acetate (C(8) H(12) CaMgO(8) ). Acetates are sometimes touted as environmentally friendly alternatives to NaCl but have not been examined in enough detail to warrant this designation. When exposed to a range of environmentally realistic concentrations of these chemicals, larvae were least sensitive (i.e., had the lowest mortality rate) to CH(4) N(2) O, NaCl, and MgCl(2) and most sensitive to acetates (C(8) H(12) CaMgO(8) , CH(3) COOK) and CaCl(2) . Our observed median lethal concentration estimates (LC50(96-h) ) for NaCl were over two times higher than values presented in previous studies, which suggests variability in tolerance among R. sylvatica populations. The deicers varied greatly in their toxicity, and further research is warranted to examine the differential effects of this suite of deicers on other species.

  9. Mortality and antioxidant responses in the planarian (Dugesia japonica) after exposure to copper.

    PubMed

    Zhang, Xiufang; Zhang, Bowen; Yi, Hongyang; Zhao, Bosheng

    2014-03-01

    The planarians (Dugesia japonica) are distributed widely in China, Japan, Korea, and southern Siberia. In this study, the acute toxicity of copper on D. japonica was evaluated using mortality and the activity of the enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), and reactive oxygen species (ROS) as endpoints. Acute toxicity tests were conducted according to the American Society for Testing and Materials guidelines. The 24-, 48-, 72-, and 96-h median lethal concentration that killed 50% of individuals (LC50) were calculated as 8.70, 6.31, 4.48, and 4.23 mg Cu²⁺/L, respectively, based on measured copper concentrations. When compared with different phyla or classes of freshwater animals, the rank of D. japonica in species sensitivity was in the range of 25-26 for 96-h LC₅₀. The antioxidant enzymes SOD and CAT were determined in D. japonica exposed to two copper concentrations (50 and 100 μg Cu²⁺/L) with a short-term exposure (15 days). They all attained peak value and then reduced during the experimental period. The GPx activities were activated only for 100 μg/L treatments at days 3 and 6 and then renewed to the original level. Meanwhile, copper significantly increased the levels of ROS in D. japonica. Our study suggests that the adult D. japonica was less sensitive to copper than most other aquatic species. Copper may induce oxidative stress and interfere with the antioxidant defense system of the D. japonica, including SOD and CAT. GPx might be an insusceptible antioxidant enzyme in the metabolic detoxification processes in adult D. japonica.

  10. Evaluation of copper effects upon Girardia tigrina freshwater planarians based on a set of biomarkers.

    PubMed

    Knakievicz, Tanise; Ferreira, Henrique Bunselmeyer

    2008-03-01

    Copper is a common environmental contaminant, which is particularly toxic to living organisms when in high concentrations. To monitor environmental contamination by Cu2+ and other heavy metals, well characterized bioindicator organisms and standardized assays are needed. As a first step toward this end, we have analysed Cu2+ effects upon Girardia tigrina freshwater planarians, based on the assessment of mobility, regeneration performance, micronucleus (MN) frequency in regenerating animals, and reproductive performance. These four biomarkers provided complementary information on Cu2+ toxicity, teratogenicity, mutagenicity and chronic (>96 h of exposure) effects, respectively. The LC50 was calculated for newborn, adult and regenerating planarians, and values of 12+/-0.02 mg l(-1), 42+/-0.08 mg l(-1), 48+/-0.13 mg l(-1), respectively, were obtained after 96 h of exposure. Mobility, for intact adults, and time of regeneration and MN frequency, for regenerating animals, were significantly affected by Cu2+ concentrations as low as 0.10 mg l(-1). MN assay for regenerating G. tigrina neoblasts showed higher sensitivities than MN assays performed with other bioindicator freshwater organisms, such as moluscs or fish. Chronic exposure effects were clearly evidenced by assessment of reproductive performance, with significant reduction in fecundity and fertility rates upon exposure to Cu2+ concentrations as low as 0.05 mg l(-1). Therefore, G. tigrina can be regarded as a useful bioindicator species for the detection and evaluation of Cu2+ effects upon freshwater invertebrates, allowing insights on the effects of Cu2+ (and possibly other heavy metals) in a freshwater environment.

  11. Comparative toxicity and bioconcentration of nonylphenol in freshwater organisms.

    PubMed

    Spehar, Robert L; Brooke, Larry T; Markee, Thomas P; Kahl, Michael D

    2010-09-01

    Degradation of alkylphenol ethoxylates to more persistent alkylphenols such as nonylphenol occurs in wastewater treatment plants where nonylphenol is released to aquatic systems. In this study, acute and chronic tests were conducted to determine the toxicity and bioconcentration of nonylphenol to freshwater organisms for use in deriving national water quality criteria. Acute median effect concentrations (EC50s) based on loss of equilibrium, immobility, and lethality for species representing several taxonomic groups ranged from 21 to 596 microg/L. The EC50s were up to a factor of 2 less than median lethal concentrations (LC50s) and decreased with time over the test periods of 24 to 96 h. In chronic tests, early life stages of rainbow trout were 14 times more sensitive to nonylphenol than in acute tests and approximately 20 times more sensitive than Daphnia magna exposed over their complete life cycle. Comparisons of chronic test endpoints showed that 20% effect concentrations (EC20s), determined by regression testing, and chronic values, determined by hypothesis testing, were similar for both the rainbow trout and Daphnia magna. The lowest mean tissue-effect concentrations of nonylphenol appeared to be greater for the fathead minnow than bluegill, and ranged from approximately 130 to 160 microg/g after 96-h exposure and from approximately 20 to 90 microg/g after 28-d exposure. Mean lipid normalized bioconcentration factors (BCFs) associated with no-effect concentrations were approximately 180 and 50 for the fathead minnow and bluegill, respectively. The present test results suggest that long-term exposures to nonylphenol at concentrations found in some surface waters could adversely impact sensitive components of freshwater communities.

  12. Comparative toxicity and bioconcentration of nonylphenol in freshwater organisms.

    PubMed

    Spehar, Robert L; Brooke, Larry T; Markee, Thomas P; Kahl, Michael D

    2010-09-01

    Degradation of alkylphenol ethoxylates to more persistent alkylphenols such as nonylphenol occurs in wastewater treatment plants where nonylphenol is released to aquatic systems. In this study, acute and chronic tests were conducted to determine the toxicity and bioconcentration of nonylphenol to freshwater organisms for use in deriving national water quality criteria. Acute median effect concentrations (EC50s) based on loss of equilibrium, immobility, and lethality for species representing several taxonomic groups ranged from 21 to 596 microg/L. The EC50s were up to a factor of 2 less than median lethal concentrations (LC50s) and decreased with time over the test periods of 24 to 96 h. In chronic tests, early life stages of rainbow trout were 14 times more sensitive to nonylphenol than in acute tests and approximately 20 times more sensitive than Daphnia magna exposed over their complete life cycle. Comparisons of chronic test endpoints showed that 20% effect concentrations (EC20s), determined by regression testing, and chronic values, determined by hypothesis testing, were similar for both the rainbow trout and Daphnia magna. The lowest mean tissue-effect concentrations of nonylphenol appeared to be greater for the fathead minnow than bluegill, and ranged from approximately 130 to 160 microg/g after 96-h exposure and from approximately 20 to 90 microg/g after 28-d exposure. Mean lipid normalized bioconcentration factors (BCFs) associated with no-effect concentrations were approximately 180 and 50 for the fathead minnow and bluegill, respectively. The present test results suggest that long-term exposures to nonylphenol at concentrations found in some surface waters could adversely impact sensitive components of freshwater communities. PMID:20821669

  13. Values beyond value? Is anything beyond the logic of capital?

    PubMed

    Skeggs, Bev

    2014-03-01

    We are living in a time when it is frequently assumed that the logic of capital has subsumed every single aspect of our lives, intervening in the organization of our intimate relations as well as the control of our time, including investments in the future (e.g. via debt). The theories that document the incursion of this logic (often through the terms of neoliberalism and/or governmentality) assume that this logic is internalized, works and organizes everything including our subjectivity. These theories performatively reproduce the very conditions they describe, shrinking the domain of values and making it subject to capital's logic. All values are reduced to value. Yet values and value are always dialogic, dependent and co-constituting. In this paper I chart the history by which value eclipses values and how this shrinks our sociological imagination. By outlining the historical processes that institutionalized different organizations of the population through political economy and the social contract, producing ideas of proper personhood premised on propriety, I detail how forms of raced, gendered and classed personhood was formed. The gaps between the proper and improper generate significant contradictions that offer both opportunities to and limits on capitals' lines of flight. It is the lacks, the residues, and the excess that cannot be captured by capital's mechanisms of valuation that will be explored in order to think beyond the logic of capital and show how values will always haunt value. PMID:24571532

  14. Values beyond value? Is anything beyond the logic of capital?

    PubMed

    Skeggs, Bev

    2014-03-01

    We are living in a time when it is frequently assumed that the logic of capital has subsumed every single aspect of our lives, intervening in the organization of our intimate relations as well as the control of our time, including investments in the future (e.g. via debt). The theories that document the incursion of this logic (often through the terms of neoliberalism and/or governmentality) assume that this logic is internalized, works and organizes everything including our subjectivity. These theories performatively reproduce the very conditions they describe, shrinking the domain of values and making it subject to capital's logic. All values are reduced to value. Yet values and value are always dialogic, dependent and co-constituting. In this paper I chart the history by which value eclipses values and how this shrinks our sociological imagination. By outlining the historical processes that institutionalized different organizations of the population through political economy and the social contract, producing ideas of proper personhood premised on propriety, I detail how forms of raced, gendered and classed personhood was formed. The gaps between the proper and improper generate significant contradictions that offer both opportunities to and limits on capitals' lines of flight. It is the lacks, the residues, and the excess that cannot be captured by capital's mechanisms of valuation that will be explored in order to think beyond the logic of capital and show how values will always haunt value.

  15. Efficacy of some plant oils alone and/or combined with different insecticides on the cotton leaf-worm Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) in Egypt.

    PubMed

    Mesbah, H A; Mourad, A K; Rokaia, A Z M

    2006-01-01

    tested mixtures of Clove and Sesame oils increased the percentage of larval mortality in comparison to their use alone against the treated 4th larval instar.Contrarily, antagonism was revealed for the mixture of Sesame/Flax oils, the calculated value of LC50 greatly increased compared to the corresponding values of their individual evaluation after 48 h. from initiating the treatment. The delayed effect of tested plant oils was inspected on certain parameters of the fitness components of the subject insect and was mainly determined for the rates of hatched eggs and emerged moths. Remarkably, the Methoxyfenozide treated 4th larval instar became passive, or ceased feeding on the treated leaves and were unable to complete normally the moulting process, which partially took place in most'of the other treated individuals. The treated larvae with the tested lower concentrations, hardly succeeded in completing moulting process. The survived larvae failed to complete the next moulting at the end of the treatments. The toxic effect of Spinosad was more apparent against the treated larvae after 72 h from application. The calculated LC50 values indicated the gradual increase of its toxic effect in the subsequent prolonged intervals of the test. Spinosad showed its activity either by contact or ingestion and caused larval characteristic symptoms. Permethrin exhibited superior toxic efficacy overall the other tested chemicals, during the period from 72 up to 96 h post treatment. The gradual increase of the toxic effect of Permethrin indicated an efficient continuous persistence of nervous toxicity. According to the specific properties of Profenofos, results revealed that the toxicity by ingestion was more potential than by contact and explained the reason of developing toxicity with the increase of bioassay inspection period. The comparative toxic efficiency of the tested insecticides proved that Permethrin was the most effective one, giving LC50 values of 2.92 and 1.53 ppm after 72

  16. Beyond Values Clarification: Addressing Client Values in Clinical Behavior Analysis

    ERIC Educational Resources Information Center

    Bonow, Jordan T.; Follette, William C.

    2009-01-01

    Ethical principles of psychology, as exemplified in the American Psychological Association (APA) Code of Ethics (2002), provide impractical advice for addressing client values during psychotherapy. These principles seem to argue that each client's values should be respected and protected at all times, except in cases in which this would result in…

  17. What Is the Value of Value-Based Purchasing?

    PubMed

    Tanenbaum, Sandra J

    2016-10-01

    Value-based purchasing (VBP) is a widely favored strategy for improving the US health care system. The meaning of value that predominates in VBP schemes is (1) conformance to selected process and/or outcome metrics, and sometimes (2) such conformance at the lowest possible cost. In other words, VBP schemes choose some number of "quality indicators" and financially incent providers to meet them (and not others). Process measures are usually based on clinical science that cannot determine the effects of a process on individual patients or patients with comorbidities, and do not necessarily measure effects that patients value; additionally, there is no provision for different patients valuing different things. Proximate outcome measures may or may not predict distal ones, and the more distal the outcome, the less reliably it can be attributed to health care. Outcome measures may be quite rudimentary, such as mortality rates, or highly contestable: survival or function after prostate surgery? When cost is an element of value-based purchasing, it is the cost to the value-based payer and not to other payers or patients' families. The greatest value of value-based purchasing may not be to patients or even payers, but to policy makers seeking a morally justifiable alternative to politically contested regulatory policies.

  18. Attitudes of Social Studies Teachers toward Value and Values Education

    ERIC Educational Resources Information Center

    Celikkaya, Tekin; Filoglu, Simge

    2014-01-01

    This research was conducted to determine how social studies teachers define value and "values education" as well as reveal the problems they encountered during the implementation. The participants in this study consisted of 17 social studies teachers from 12 primary schools (selected out of 39 primary schools in the city of Kirsehir…

  19. What Is the Value of Value-Based Purchasing?

    PubMed

    Tanenbaum, Sandra J

    2016-10-01

    Value-based purchasing (VBP) is a widely favored strategy for improving the US health care system. The meaning of value that predominates in VBP schemes is (1) conformance to selected process and/or outcome metrics, and sometimes (2) such conformance at the lowest possible cost. In other words, VBP schemes choose some number of "quality indicators" and financially incent providers to meet them (and not others). Process measures are usually based on clinical science that cannot determine the effects of a process on individual patients or patients with comorbidities, and do not necessarily measure effects that patients value; additionally, there is no provision for different patients valuing different things. Proximate outcome measures may or may not predict distal ones, and the more distal the outcome, the less reliably it can be attributed to health care. Outcome measures may be quite rudimentary, such as mortality rates, or highly contestable: survival or function after prostate surgery? When cost is an element of value-based purchasing, it is the cost to the value-based payer and not to other payers or patients' families. The greatest value of value-based purchasing may not be to patients or even payers, but to policy makers seeking a morally justifiable alternative to politically contested regulatory policies. PMID:27256808

  20. The Values and Value Systems of Educational Administrators.

    ERIC Educational Resources Information Center

    Sikula, Andrew F.; Sikula, John P.

    This speech reports on a study of 62 educational administrators that supplies empirical evidence in support of the contention that there are significantly different profiles associated with different occupational-career groups. Utilizing the Rokeach Value Survey Form D, the authors surveyed and compared the value configurations of 12 distinct…

  1. Do laboratory salinity tolerances of freshwater animals correspond with their field salinity?

    PubMed

    Kefford, Ben J; Papas, Phil J; Metzeling, Leon; Nugegoda, Dayanthi

    2004-06-01

    The degree to which laboratory derived measures of salinity tolerance reflect the field distributions of freshwater biota is uncertain. In this paper we compare laboratory-derived acute salinity tolerance (LC(50) values) of freshwater macroinvertebrates (range 5.5-76 mS/cm) and fish (range 2.7-82 mS/cm) from southeastern Australia with the salinity from which they have been collected in the field. Only 4% of the macroinvertebrates were collected at salinity levels substantially higher than their 72-h LC(50) obtained from directly transferring animals from low salinity water to the water they were tested (direct transfer LC(50)). This LC(50) value was correlated with the maximum salinity at which a species had been collected. For common macroinvertebrates, the maximum field salinity was approximated by the direct transfer 72-h LC(50). For adult freshwater fish, 21% of species were collected at salinities substantially greater than their acute direct transfer LC(50) and there was a weak relationship between these two variables. Although there was a weak correlation between the direct transfer LC(50) of early life stages of freshwater fish and the maximum field salinity, 58% of the field distribution were in higher than their LC(50) values. In contrast, LC(50) determined from experiments that acclimated adult fish to higher salinity (slow acclimation) provided a better indication of the field distribution: with only one fish species (7%) being in conflict with their maximum field salinity and a strong positive relationship between these variables. This study shows that laboratory measures of acute salinity tolerance can reflect the maximum salinity that macroinvertebrate and fish species inhabit and are consistent with some anecdotal observations from other studies. PMID:15016457

  2. [Acute Toxicity and Safety Assessment of Three Typical Organic Pollutants to Two Aquatic Organisms].

    PubMed

    Yang, Yang; Li, Ya-jie; Cui, Yi-bin; Li, Mei

    2015-08-01

    Acute toxic effects of three typical organic pollutants 1 ,2,4-trichlorobenzene (1,2,4-TCB), nitrobenzene and chlorpyrifos were investigated using Tetrahymena thermophila and Limnodrilus hoffmeisteri as living test organisms under laboratory conditions. The results showed that with the increase of pollutants' concentration and the extension of time, toxicity of the three kinds of pollutants significantly enhanced, and the mortality of two kinds of aquatic organisms also had a rising trend, and an obvious dose-effect relationship. The 96 h-LC50. values of 1 ,2, 4-TCB, nitrobenzene and chlorpyrifos were 71.88, 285.76, and 5.50 mg x L(-1) for L. hoffmeisteri and 15.58, 140.22, and 14.69 mg x L(-1) for T. thermophila. These results showed that the toxicity among the three typical pollutants to T. thermophila was 1 , 2,4-TCB > chlorpyrifos > nitrobenzene. Findings were able to provide more information on water quality criteria and more data on their toxicity to indigenous aquatic organisms in China. PMID:26592043

  3. Using phylogenetic information and chemical properties to predict species tolerances to pesticides.

    PubMed

    Guénard, Guillaume; Carsten von der Ohe, Peter; Carlisle Walker, Steven; Lek, Sovan; Legendre, Pierre

    2014-08-22

    Direct estimation of species' tolerance to pesticides and other toxic organic substances is a combinatorial problem, because of the large number of species-substance pairs. We propose a statistical modelling approach to predict tolerances associated with untested species-substance pairs, by using models fitted to tested pairs. This approach is based on the phylogeny of species and physico-chemical descriptors of pesticides, with both kinds of information combined in a bilinear model. This bilinear modelling approach predicts tolerance in untested species-compound pairs based on the facts that closely related species often respond similarly to toxic compounds and that chemically similar compounds often have similar toxic effects. The three tolerance models (median lethal concentration after 96 h) used up to 25 aquatic animal species and up to nine pesticides (organochlorines, organophosphates and carbamates). Phylogeny was estimated using DNA sequences, while the pesticides were described by their mode of toxic action and their octanol-water partition coefficients. The models explained 77-84% of the among-species variation in tolerance (log10 LC50). In cross-validation, 84-87% of the predicted tolerances for individual species were within a factor of 10 of the observed values. The approach can also be used to model other species response to multivariate stress factors.

  4. Short-term effects of military fog oil on the fountain darter (Etheostoma fonticola).

    PubMed

    Ryan, T A; Kohl, A N; Soucek, D J; Smith, T S; Brandt, T M; Bonner, T H; Cropek, D M

    2013-11-01

    Toxicity tests evaluated chronic and sublethal effects of fog oil (FO) on a freshwater endangered fish. FO is released during military training as an obscurant smoke that can drift into aquatic habitats. Fountain darters, Etheostoma fonticola, of four distinct life stages were exposed under laboratory conditions to three forms of FO. FO was vaporized into smoke and allowed to settle onto water, violently agitated with water, and dosed onto water followed by photo-oxidization by ultraviolet irradiation. Single smoke exposures of spawning adult fish did not affect egg production, egg viability, or adult fish survival in 21-day tests. Multiple daily smoke exposures induced mortality after 5 days for larvae fish. Larvae and juvenile fish were more sensitive than eggs in 96-h lethal concentration (LC50) tests with FO–water mixtures and photo-oxidized FO. Water-soluble FO components photo-modified by ultraviolet radiation were the most toxic, thus indicating the value of examining weathering and aging of chemicals for the best determination of environmental impact.

  5. Sublethal exposure to crude oil enhances positive phototaxis in the calanoid copepod Calanus finmarchicus.

    PubMed

    Miljeteig, Cecilie; Olsen, Anders Johny; Nordtug, Trond; Altin, Dag; Jenssen, Bjørn Munro

    2013-12-17

    We investigated the effects of exposure to sublethal concentrations of the water accommodated fraction (WAF) of fresh crude oil on phototactic behavior of the calanoid copepod Calanus finmarchicus (Gunnerus) copepodite stage 5 (C5). Exposure was conducted in closed bottle systems, and behavior was tested in a tailored setup. Exposure times were 24, 48, 72, and 96 h, and the chosen exposure concentration was 25% of the recorded LC50 value for the WAF (309 ± 32 μg/L total hydrocarbon, including 20.37 ± 0.51 μg/L total PAH). The exposure significantly increased the positive phototactic behavior of the copepods after 24 h exposure and a similar significant effect was observed for all exposure durations. Additionally, experiments were conducted with nonexposed copepods with low lipid reserves. The main effect of the exposure was a shift in the response to light toward a more positive phototaxis, similar to that observed in nonexposed C. finmarchicus with low lipid reserves. The observed change in phototactic behavior observed in these studies suggests that the depth distribution of this species could be altered following an oil spill. Thus, further research is warranted to determine the possible interactive effects of light and oil spill exposures on Calanus population dynamics under field conditions. PMID:24219329

  6. Effects of a nonionic surfactant (C{sub 14-15} AE-7) on fish survival, growth and reproduction in the laboratory and in outdoor stream mesocosms

    SciTech Connect

    Kline, E.R.; Figueroa, R.A.; Rodgers, J.H. Jr.; Dorn, P.B.

    1996-06-01

    The effects of a nonionic surfactant (C{sub 14-15} AE-7) on survival and growth of juvenile bluegill sunfish and on survival and reproduction of fathead minnows were investigated in the laboratory and in outdoor stream mesocosms. In the laboratory, where the fish were exposed for 10 d, the 96-h LC50 values for bluegill sunfish and fathead minnows were 650 and 770 {micro}g/L, respectively. The no-observed-effect concentration (NOEC) for survival and swimming performance of bluegill sunfish and for survival of fathead minnows was 160 {micro}g/L. The lowest-observed-effect concentration (LOEC) for these toxic responses was 460 {micro}g/L. In the stream mesocosms, where the fish were exposed for 30 d, the NOEC for bluegill sunfish and growth was >330 {micro}g/L. The LOEC for fathead minnow survival was 330 {micro}g/L, and the NOEC was 280 {micro}g/L. Decreased egg laying by fathead minnows was noted in the streams at concentrations of 330 {micro}g/L or greater. Close correspondence between the results of laboratory tests and those obtained under field conditions in the mesocosms indicates that for this surfactant, it may not be necessary to apply ``safety factors`` to extrapolate results from the laboratory to the field.

  7. Migration of nonylphenol from food-grade plastic is toxic to the coral reef fish species Pseudochromis fridmani.

    PubMed

    Hamlin, Heather J; Marciano, Kathleen; Downs, Craig A

    2015-11-01

    Nonylphenol (NP) is a non-ionic surfactant used extensively in industrial applications, personal care products, and many plastics. We exposed marine orchid dottybacks (Pseudochromis fridmani) for 48h to either glass, Teflon, or two bags labeled as FDA food-grade polyethylene (PE1 and PE2) from different manufacturers. The PE2 bags leached high levels of NP into the contact water, which were taken up by the fish, and decreased short and long-term survival. Concentrations of NP that leached from the bags were consistent with 96h LC50 values determined in this study, indicating NP is the likely toxic agent. Despite being similarly labeled, the NP concentrations that leached from the bags and the resultant toxicity to the fish varied dramatically between manufacturers. This study highlights that some plastics, labeled as food-safe, can be highly toxic to aquatic animals, and could pose a greater threat to humans than previously realized. This study also highlights risks for aquatic animals exposed to increasing quantities of plastic waste.

  8. Effects of road de-icing salt (NaCl) on larval wood frogs (Rana sylvatica).

    PubMed

    Sanzo, Domenico; Hecnar, Stephen J

    2006-03-01

    Vast networks of roads cover the earth and have numerous environmental effects including pollution. A major component of road runoff in northern countries is salt (mostly NaCl) used as a winter de-icing agent, but few studies of effects of road salts on aquatic organisms exist. Amphibians require aquatic habitats and chemical pollution is implicated as a major factor in global population declines. We exposed wood frog tadpoles to NaCl. Tests revealed 96-h LC50 values of 2,636 and 5,109 mg/l and tadpoles experienced reduced activity, weight, and displayed physical abnormalities. A 90 d chronic experiment revealed significantly lower survivorship, decreased time to metamorphosis, reduced weight and activity, and increased physical abnormalities with increasing salt concentration (0.00, 0.39, 77.50, 1,030.00 mg/l). Road salts had toxic effects on larvae at environmentally realistic concentrations with potentially far-ranging ecological impacts. More studies on the effects of road salts are warranted.

  9. Migration of nonylphenol from food-grade plastic is toxic to the coral reef fish species Pseudochromis fridmani.

    PubMed

    Hamlin, Heather J; Marciano, Kathleen; Downs, Craig A

    2015-11-01

    Nonylphenol (NP) is a non-ionic surfactant used extensively in industrial applications, personal care products, and many plastics. We exposed marine orchid dottybacks (Pseudochromis fridmani) for 48h to either glass, Teflon, or two bags labeled as FDA food-grade polyethylene (PE1 and PE2) from different manufacturers. The PE2 bags leached high levels of NP into the contact water, which were taken up by the fish, and decreased short and long-term survival. Concentrations of NP that leached from the bags were consistent with 96h LC50 values determined in this study, indicating NP is the likely toxic agent. Despite being similarly labeled, the NP concentrations that leached from the bags and the resultant toxicity to the fish varied dramatically between manufacturers. This study highlights that some plastics, labeled as food-safe, can be highly toxic to aquatic animals, and could pose a greater threat to humans than previously realized. This study also highlights risks for aquatic animals exposed to increasing quantities of plastic waste. PMID:26134675

  10. Pirimicarb-based formulation-induced genotoxicity and cytotoxicity in the freshwater fish Cnesterodon decemmaculatus (Jenyns, 1842) (Pisces, Poeciliidae).

    PubMed

    Vera-Candioti, Josefina; Soloneski, Sonia; Larramendy, Marcelo L

    2015-11-01

    We analyzed the aspects of lethality, genotoxicity, and cytotoxicity in the ten spotted live-bearer exposed under laboratory conditions to the pirimicarb-based formulation Patton Flow® (50% active ingredient (a.i.)). Acute effects were evaluated using different end points for lethality, genotoxicity, and cytotoxicity. Median lethal concentration (LC50) estimation was employed as a bioassay for lethality, whereas micronucleus (MN) induction and alterations in erythrocyte/erythroblast frequency were used as end points for genotoxicity and cytotoxicity, respectively. Results demonstrated an LC5096h value of 88 mg/L. Patton Flow® increased the MN frequency in fish erythrocytes after 48 h of exposure at a concentration of 66 mg/L, whereas a concentration range of 22-66 mg/L was able to exert the same genotoxic effect at 96 h of treatment. Furthermore, cytotoxicity was also observed by alterations in erythrocyte/erythroblast frequencies within the concentration range of 22-66 mg/L, regardless of the exposure time. Our current observations provide evidence that Patton Flow® (50% a.i.) should be considered a clear lethal, cytotoxic, and genotoxic agent on Cnesterodon decemmaculatus. Thus, repeated applications of this carbamic insecticide can enter the aquatic environment and exert deleterious effects on aquatic organisms other than the evaluated species C. decemmaculatus.

  11. FETAX interlaboratory validation study: Phase 2 testing

    SciTech Connect

    Bantle, J.A. . Dept. of Zoology); Burton, D.T. ); Dawson, D.A. . Dept. of Biology and Toxicology)

    1994-10-01

    The Frog Embryo Teratogenesis Assay-Xenopus (FETAX) is a 96-h whole embryo developmental toxicity screening assay that can be used in ecotoxicology and in detecting mammalian developmental toxicants when an in vitro metabolic activation system is employed. A standardized American Society for Testing and Materials (ASTM) guide for the conduct of FETAX has been published along with a companion atlas that helps in embryo staging and identifying malformations. As part of the ASTM process, an interlaboratory validation study was undertaken to evaluate the repeatability and reliability of FETAX. Six different laboratories participated in the study. Each laboratory utilized one technician with the exception of one laboratory, which utilized two independent technicians. In Phase 1, FETAX proved to be more repeatable and reliable than many other bioassays. However, some excessive variation was observed in a few laboratories. Some of this variation may have been due to an initial lack of experience with the assay by some technicians. Phase 2, which is reported here, showed far less intralaboratory and interlaboratory variability than did Phase 1. Nonteratogens such as saccharin and sodium cyclamate showed the most consistent results, whereas more variability was observed for the teratogens caffeine and 5-fluorouracil. Interlaboratory coefficient of variation values for all FETAX end points ranged from 7.3 to 54.7%. The minimum concentration to inhibit growth proved to be the most variable end point for three of the four test chemicals, whereas the LC50 and EC50 (malformation) proved to be less variable.

  12. Humic substances of varying types increase survivorship of the freshwater shrimp Caridina sp. D to acid mine drainage.

    PubMed

    Holland, Aleicia; Duivenvoorden, Leo J; Kinnear, Susan H W

    2014-07-01

    Differences relating to the ability of various types of humic substances (HS) to influence toxicity of pollutants have been reported in the literature, but there still remains a gap in understanding whether various HS will have the same influence on the toxicity of acid mine drainage (AMD). This study investigated differences in the ability of Aldrich humic acid (AHA), Suwannee River humic acid and Suwannee River fulvic acid to decrease toxicity of AMD to the freshwater shrimp (Caridina sp. D). Toxicity tests were conducted over 96 h and used Mount Morgan open pit water as source of AMD and Dee River water as control/diluents. Concentrations of 0-4 % AMD at 0 mg/L HS, 10 mg/L AHA, 10 mg/L Suwannee River humic acid and 10 mg/L Suwannee River fulvic acid were used. Significantly higher survival of shrimp was recorded in the HS treatments compared with the treatment containing no HS. No significant differences were found among HS type. HS considerably increased LC50 values irrespective of type, from 1.29 (0 mg/L HS) to 2.12 % (AHA); 2.19 (Suwannee River humic acid) and 2.22 % (Suwannee River fulvic acid). These results support previous work that HS decrease the toxicity of AMD to freshwater organisms, but with the novel finding that this ability occurs irrespective of HS type. These results increase the stock of knowledge regarding HS and may contribute to a possible remediation option for AMD environments. PMID:24715599

  13. Effect of Lipid Partitioning on Predictions of Acute Toxicity of Oil Sands Process Affected Water to Embryos of Fathead Minnow (Pimephales promelas).

    PubMed

    Morandi, Garrett D; Zhang, Kun; Wiseman, Steve B; Pereira, Alberto Dos Santos; Martin, Jonathan W; Giesy, John P

    2016-08-16

    Dissolved organic compounds in oil sands process affected water (OSPW) are known to be responsible for most of its toxicity to aquatic organisms, but the complexity of this mixture prevents use of traditional bottom-up approaches for predicting toxicities of mixtures. Therefore, a top-down approach to predict toxicity of the dissolved organic fraction of OSPW was developed and tested. Accurate masses (i.e., m/z) determined by ultrahigh resolution mass spectrometry in negative and positive ionization modes were used to assign empirical chemical formulas to each chemical species in the mixture. For each chemical species, a predictive measure of lipid accumulation was estimated by stir-bar sorptive extraction (SBSE) to poly(dimethyl)siloxane, or by partitioning to solid-supported lipid membranes (SSLM). A narcosis mode of action was assumed and the target-lipid model was used to estimate potencies of mixtures by assuming strict additivity. A model developed using a combination of the SBSE and SSLM lipid partitioning estimates, whereby the accumulation of chemicals to neutral and polar lipids was explicitly considered, was best for predicting empirical values of LC50 in 96-h acute toxicity tests with embryos of fathead minnow (Pimephales promelas). Model predictions were within 4-fold of observed toxicity for 75% of OSPW samples, and within 8.5-fold for all samples tested, which is comparable to the range of interlaboratory variability for in vivo toxicity testing. PMID:27420640

  14. Environmental effects of sodium Acetate/Formate deicer, ice sheartrade mark

    PubMed

    Bang; Johnston

    1998-11-01

    The environmental impacts of Ice Sheartrade mark, an alternative highway deicer, have been evaluated using standard laboratory tests; biochemical oxygen demand (BOD) tests, chemical oxygen demand (COD) tests, acute rainbow trout bioassays, and phytotoxicity tests were used. Ice Shear consists of equimolar sodium acetate and sodium formate. The organic matter of the deicer can be readily degraded microbiologically in the natural environment with a slow rate of degradation at lower temperatures but an increased rate at higher temperatures. At elevated temperatures, highway runoffs of the deicer may reduce the level of dissolved oxygen in the receiving waters to cause an adverse impact. However, the apparent activation energy calculated for the BOD rate of Ice Shear is low (8.78 kcal mole-1), indicating that the temperature variation may not significantly influence the biodegradation of the deicer compound. Ice Shear appears relatively harmless to aquatic animals, showing a high 96-h LC50 value (16.1 g/L) derived for rainbow trout (Oncorhynchus mykiss). Ice Shear causes minimal toxicity to representative roadside vegetation; herbaceous (e.g., sunflowers, beans, and lettuce) and woody (e.g., pine seedlings) plants. Rather, the deicer at low concentrations (less than 2 g/kg soil) seems to work as a fertilizer, promoting the yield of biomass. The test results indicate that Ice Shear poses minimal environmental disturbance in both aquatic and terrestrial ecosystems.

  15. Effects of waterborne nickel on the physiological and immunological parameters of the Pacific abalone Haliotis discus hannai during thermal stress.

    PubMed

    Min, Eun Young; Cha, Yong-Joo; Kang, Ju-Chan

    2015-09-01

    In this study, the 96-h LC50 at 22 and 26 °C values was 28.591 and 11.761 mg/L, respectively, for NiCl2 exposure in the abalone. The alteration of physiological and immune-toxicological parameters such as the total hemocyte count (THC), lysozyme, phenoloxidase (PO), and phagocytosis activity was measured in the abalone exposed to nickel (200 and 400 μg/L) under thermal stress for 96 h. In this study, Mg and THC decreased, while Ca, lysozyme, PO, and phagocytosis activity increased in the hemolymph of Pacific abalone exposed to NiCl2 when compared to a control at both 22 and 26 °C. However, these parameters were not affected by a rise in temperature from 22 to 26 °C in non-exposed groups. Our results showed that NiCl2 below 400 μg/L was able to stimulate immune responses in abalone. However, complex stressors, thermal changes, or NiCl2 can modify the immunological response and lead to changes in the physiology of host-pollutant interactions in the abalone. PMID:25943513

  16. Sensitivity of isolated eggs of pond snails: a new method for toxicity assays and risk assessment.

    PubMed

    Liu, Tengteng; Koene, Joris M; Dong, Xiaoxiao; Fu, Rongshu

    2013-05-01

    The concentration of heavy metals in the environment is normally low. We here address whether using the development of isolated pond snail Radix auricularia eggs would provide a more sensitive endpoint and whether the gelatinous matrix of the egg mass surrounding the eggs indeed protects the snail embryos. In the present study, artificial removal of the gelatinous matrix of egg masses greatly increased the sensitivity of developing eggs to a heavy metal (cadmium). The sensitivity of isolated eggs to cadmium was determined using several convenient endpoints, including mortality, hatching rate, and heart rate, with an acute toxicity test and a subchronic test. In the acute toxicity test, a 96-h LC(50) value of 58.26 μg/L cadmium was determined. In the subchronic toxicity test, sublethal effects in terms of a significant reduction in hatching rate could be found in the 25-μg/L treatment, and a significant decrease of heart rate was observed in both treatments (5 and 25 μg/L). The high sensitivity of isolated eggs indicates that such tests can be efficient for toxicity assays and risk assessment, although one needs to keep in mind that the ecologically relevant measure of toxicity will be how eggs are affected when they are still inside the egg mass.

  17. Effects of waterborne nickel on the physiological and immunological parameters of the Pacific abalone Haliotis discus hannai during thermal stress.

    PubMed

    Min, Eun Young; Cha, Yong-Joo; Kang, Ju-Chan

    2015-09-01

    In this study, the 96-h LC50 at 22 and 26 °C values was 28.591 and 11.761 mg/L, respectively, for NiCl2 exposure in the abalone. The alteration of physiological and immune-toxicological parameters such as the total hemocyte count (THC), lysozyme, phenoloxidase (PO), and phagocytosis activity was measured in the abalone exposed to nickel (200 and 400 μg/L) under thermal stress for 96 h. In this study, Mg and THC decreased, while Ca, lysozyme, PO, and phagocytosis activity increased in the hemolymph of Pacific abalone exposed to NiCl2 when compared to a control at both 22 and 26 °C. However, these parameters were not affected by a rise in temperature from 22 to 26 °C in non-exposed groups. Our results showed that NiCl2 below 400 μg/L was able to stimulate immune responses in abalone. However, complex stressors, thermal changes, or NiCl2 can modify the immunological response and lead to changes in the physiology of host-pollutant interactions in the abalone.

  18. Examination of an amphibian-based assay using the larvae of Xenopus laevis and Ambystoma mexicanum.

    PubMed

    Saka, Masahiro

    2003-05-01

    Semistatic acute toxicity tests of amphibian larvae (Xenopus laevis and Ambystoma mexicanum) were conducted at different developmental stages and by different methods to establish a simple amphibian-based assay. Test substance was pentachlorophenol sodium salt (PCP-Na). The endpoint was mortality and the 24-, 48-, 72-, and 96-h LC50 values were calculated by probit analysis. Interspecific differences in larval responses were not clear. Larval sensitivity tended to increase with larval age. Newly hatched larvae were most resistant to PCP-Na. During the tests of well-developed larvae, concentrations of dissolved oxygen and PCP-Na in the test solutions greatly dropped owing to uptake by the larvae. Therefore, middle-developed (2-week-old) larvae were most suitable for the test. Toxicity tests for volatile substances would be also possible using 2-week-old larvae in closed vessels. Test individuals should be kept individually to avoid the effects of poisonous skin secretions released from dead larvae. PMID:12706392

  19. Potential anthelmintics: polyphenols from the tea plant Camellia sinensis L. are lethally toxic to Caenorhabditis elegans.

    PubMed

    Mukai, Daisuke; Matsuda, Noriko; Yoshioka, Yu; Sato, Masashi; Yamasaki, Toru

    2008-04-01

    A novel gallate of tannin, (-)-epigallocatechin-(2 beta-->O-->7',4 beta-->8')-epicatechin-3'-O-gallate (8), together with (-)-epicatechin-3-O-gallate (4), (-)-epigallocatechin (5), (-)-epigallocatechin-3-O-gallate (6), and (+)-gallocatechin-(4 alpha-->8')-epigallocatechin (7), were isolated from the tea plant Camellia sinensis (L.) O. Kuntze var. sinensis (cv., Yabukita). The structure of 8, including stereochemistry, was elucidated by spectroscopic methods and hydrolysis. The compounds, along with commercially available pyrogallol (1), (+)-catechin (2), and (-)-epicatechin (3), were examined for toxicity towards egg-bearing adults of Caenorhabditis elegans. The anthelmintic mebendazole (9) was used as a positive control. Neither 2 nor 3 were toxic but the other compounds were toxic in the descending order 8, 7 approximately 6, 9, 4, 5, 1. The LC(50) (96 h) values of 8 and 9 were evaluated as 49 and 334 micromol L(-1), respectively. These data show that many green tea polyphenols may be potential anthelmintics. PMID:18404315

  20. Values Education: Texts and Supplements.

    ERIC Educational Resources Information Center

    Curriculum Review, 1979

    1979-01-01

    This column describes and evaluates almost 40 texts, instructional kits, and teacher resources on values, interpersonal relations, self-awareness, self-help skills, juvenile psychology, and youth suicide. Eight effective picture books for the primary grades and seven titles in values fiction for teens are also reviewed. (SJL)

  1. Education, Values and the Future.

    ERIC Educational Resources Information Center

    Goldsmith, Marlene Herbert

    The paper examines the relationship of values to education and stresses the need to design socially relevant educational systems. Problems which have contributed to the failure of most educational systems to reflect overall cultural values are identified. These include that educators are often oblivious to social needs and are unwilling to suggest…

  2. Be Resolute about Absolute Value

    ERIC Educational Resources Information Center

    Kidd, Margaret L.

    2007-01-01

    This article explores how conceptualization of absolute value can start long before it is introduced. The manner in which absolute value is introduced to students in middle school has far-reaching consequences for their future mathematical understanding. It begins to lay the foundation for students' understanding of algebra, which can change…

  3. Legal Implications of Values Education.

    ERIC Educational Resources Information Center

    Shaw, Brian C.; Cummings, Daniel L.

    Americans traditionally have looked to the public schools to play a role in transmitting society's values to students, and on various occasions the U.S. Supreme Court has emphasized the role of the nation's schools in inculcating basic values. For many years Maine has had a statute mandating the teaching of virtue and morality and another that…

  4. Age Stratification and Value Orientations.

    ERIC Educational Resources Information Center

    Youmans, E. Grant

    Value orientations of members of younger and older age strata in 2 subcultural systems--one urban and one rural--are examined. The author looks at age stratification in a vertical sense (i.e., assessing differences existing between members of younger and older age strata), as well as in a horizontal sense (i.e., comparing the value orientations of…

  5. 77 FR 15250 - Value Engineering

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-15

    ... Proposed Rulemaking (NPRM) in the Federal Register at 76 FR 36410 soliciting public comments on its... Federal Highway Administration 23 CFR Part 627 RIN 2125-AF40 Value Engineering AGENCY: Federal Highway... of value engineering (VE) analysis in the planning and development of highway improvement...

  6. Values Strategies for Classroom Teachers.

    ERIC Educational Resources Information Center

    Lemin, Marion, Ed.; And Others

    This document is a reference for teachers to use in incorporating values education into all subject areas through the activities listed in the book. The book contains 16 chapters, of which about half provide guidelines, discussion and activities related to values in general, and half suggest activities specific to individual areas of study. In the…

  7. Valuing Confrontations with the Future

    ERIC Educational Resources Information Center

    Kelly, Joseph T.

    1978-01-01

    Suggests teaching methods and materials for use by high school and college social studies teachers as they help students develop valuing skills. Entitled Valuing Confrontation With The Future (VCF), the materials promote consideration of provocative episodes such as electrical stimulation of the human brain and a congressional ban on large pets…

  8. Social Value and Adult Learning

    ERIC Educational Resources Information Center

    Lamb, Penny

    2011-01-01

    An examination of the current government policy discourse on social value and the capturing of social impact leads immediately into the centre of the fast-moving and transforming public-sector reform agenda. The thinking around social value takes an individual to the heart of contracting, localism, the relationship between the public sector and…

  9. Personality, Sex, and Work Values.

    ERIC Educational Resources Information Center

    Hales, Loyde; Hartman, Timothy

    1978-01-01

    The Vocational Preference Inventory (VPA) and the Ohio Work Values Inventory (OWVI) were administered to 115 undergraduates. A two-factor MANOVA was performed with personality types (VPI) and sex as independent variables and work values (OWVI) as dependent variables. The F-ratios for main effects were significant. (Author/SJL)

  10. The Values of Australian Activists

    ERIC Educational Resources Information Center

    Ellerman, D. A.; Feather, N. T.

    1976-01-01

    Relevant literature on student activism was reviewed so as to discover leads for predictions about differences between activists and non-activists in the way they might be expected to rank the terminal and instrumental values from Rokeach's Value Survey. (Editor)

  11. Cross-Cultural Faculty Values.

    ERIC Educational Resources Information Center

    Keim, Marybelle C.

    1992-01-01

    Compares the terminal values of 24 visiting scholars from the People's Republic of China based at a midwestern community college with resident faculty values. The Chinese scholars ranked freedom, equality, and self-respect highest, whereas U.S. schools gave highest rankings to salvation, family security, and self-respect. Contrasts findings with a…

  12. The Value of Literacy Practices

    ERIC Educational Resources Information Center

    Esposito, Lucio; Kebede, Bereket; Maddox, Bryan

    2015-01-01

    The concepts of literacy events and practices have received considerable attention in educational research and policy. In comparison, the question of value, that is, "which literacy practices do people most value?" has been neglected. With the current trend of cross-cultural adult literacy assessment, it is increasingly important to…

  13. Absolute reliability of hamstring to quadriceps strength imbalance ratios calculated using peak torque, joint angle-specific torque and joint ROM-specific torque values.

    PubMed

    Ayala, F; De Ste Croix, M; Sainz de Baranda, P; Santonja, F

    2012-11-01

    The main purpose of this study was to determine the absolute reliability of conventional (H/Q(CONV)) and functional (H/Q(FUNC)) hamstring to quadriceps strength imbalance ratios calculated using peak torque values, 3 different joint angle-specific torque values (10°, 20° and 30° of knee flexion) and 4 different joint ROM-specific average torque values (0-10°, 11-20°, 21-30° and 0-30° of knee flexion) adopting a prone position in recreational athletes. A total of 50 recreational athletes completed the study. H/Q(CONV) and H/Q(FUNC) ratios were recorded at 3 different angular velocities (60, 180 and 240°/s) on 3 different occasions with a 72-96 h rest interval between consecutive testing sessions. Absolute reliability was examined through typical percentage error (CVTE), percentage change in the mean (CM) and intraclass correlations (ICC) as well as their respective confidence limits. H/Q(CONV) and H/Q(FUNC) ratios calculated using peak torque values showed moderate reliability values, with CM scores lower than 2.5%, CV(TE) values ranging from 16 to 20% and ICC values ranging from 0.3 to 0.7. However, poor absolute reliability scores were shown for H/Q(CONV) and H/Q(FUNC) ratios calculated using joint angle-specific torque values and joint ROM-specific average torque values, especially for H/Q(FUNC) ratios (CM: 1-23%; CV(TE): 22-94%; ICC: 0.1-0.7). Therefore, the present study suggests that the CV(TE) values reported for H/Q(CONV) and H/Q(FUNC) (≈18%) calculated using peak torque values may be sensitive enough to detect large changes usually observed after rehabilitation programmes but not acceptable to examine the effect of preventitive training programmes in healthy individuals. The clinical reliability of hamstring to quadriceps strength ratios calculated using joint angle-specific torque values and joint ROM-specific average torque values are questioned and should be re-evaluated in future research studies.

  14. Motivational beliefs, values, and goals.

    PubMed

    Eccles, Jacquelynne S; Wigfield, Allan

    2002-01-01

    This chapter reviews the recent research on motivation, beliefs, values, and goals, focusing on developmental and educational psychology. The authors divide the chapter into four major sections: theories focused on expectancies for success (self-efficacy theory and control theory), theories focused on task value (theories focused on intrinsic motivation, self-determination, flow, interest, and goals), theories that integrate expectancies and values (attribution theory, the expectancy-value models of Eccles et al., Feather, and Heckhausen, and self-worth theory), and theories integrating motivation and cognition (social cognitive theories of self-regulation and motivation, the work by Winne & Marx, Borkowski et al., Pintrich et al., and theories of motivation and volition). The authors end the chapter with a discussion of how to integrate theories of self-regulation and expectancy-value models of motivation and suggest new directions for future research.

  15. Extraction of squalene as value-added product from the residual biomass of Schizochytrium mangrovei PQ6 during biodiesel producing process.

    PubMed

    Hoang, Minh Hien; Ha, Nguyen Cam; Thom, Le Thi; Tam, Luu Thi; Anh, Hoang Thi Lan; Thu, Ngo Thi Hoai; Hong, Dang Diem

    2014-12-01

    Today microalgae represent a viable alternative source of squalene for commercial application. The species Schizochytrium mangrovei, a heterotrophic microalga, has been widely studied and provides a high amount of squalene, polyunsaturated fatty acids and has good profiles for biodiesel production. Our work was aimed at examining the squalene contents in Vietnam's heterotrophic marine microalga S. mangrovei PQ6 biomass and residues of the biodiesel process from this strain. Thin-layer chromatography and high-performance liquid chromatography (HPLC) methods were successfully applied to the determination of squalene in S. mangrovei PQ6. The squalene content and production of S. mangrovei PQ6 reached 33.00 ± 0.02 and 33.04 ± 0.03 mg g(-1) of dry cell weight; and 0.992 g L(-1) and 1.019 g L(-1) in 30 and 150 L bioreactors, respectively after 96 h of fermentation. In addition, squalene was also detected in spent biomass (approximately 80.10 ± 0.03 mg g(-1) of spent biomass) from the S. mangrovei PQ6 biodiesel production process. The structure of squalene in residues of the biodiesel process was confirmed from its nuclear magnetic resonance spectra. The results obtained from our work suggest that there is tremendous potential in the exploitation of squalene as a value-added by-product besides biodiesel from S. mangrovei PQ6 to reduce biodiesel price.

  16. SEPARATION OF SCANDIUM VALUES FORM IRON VALUES BY SOLVENT EXTRACTION

    DOEpatents

    Kuhlman, C.W. Jr.; Lang, G.P.

    1961-12-19

    A process is given for separating scandium from trivalent iron values. In this process, an aqueous nitric acid solution is contacted with a water- immiscible alkyl phosphate solution, the aqueous solution containing the values to be separated, whereby the scandium is taken up by the alkyl phosphate. The aqueous so1ution is preferably saturated with magnesium nitrate to retain the iron in the aqueous solution. (AEC)

  17. Quantitative comparisons of acute toxicity of organic chemicals to rat and fish

    SciTech Connect

    Janardan, S.K.; Olson, C.S.; Schaeffer, D.J.

    1984-12-01

    Relationships between the acute toxicity of chemicals to fish (LC50) and rat (LD50) were analyzed using a Model II regression analysis after logarithmic transformation. (Model II regression assumes errors in both variables.) Significant correlations were found among bluegill and fathead minnow LC50S and rat LD50 values for the priority pollutants. Fathead minnow and bluegill LC50S for 48 pesticides were highly correlated. No correlations were found between fishes and rats for carbamate plus organophosphate pesticides. Correlations were obtained among all species for the combined priority pollutant plus pesticide data and for chlorinated pesticides.

  18. Potential application of extracts from Indian almond (Terminalia catappa Linn.) leaves in Siamese fighting fish (Betta splendens Regan) culture.

    PubMed

    Purivirojkul, Watchariya

    2012-01-01

    almond leaf extract concentrations (6 concentrations) between the highest concentration that did not kill fish and the lowest concentration that killed all fish were used. Each concentration had three replicates (20 fish/replication). Mortality was observed after 96 hours. The LC50 value was calculated using probit analysis. The 96-h LC50 value for green and red leaf extracts was 1,765.69 and 1,651.21 ppm, respectively. When Siamese fighting fish were cultured in water added with Indian almond water extract at 5 concentrations for 5 days and then challenged with Aeromonas hydrophila at a concentration of 1 x 106 CFU/mL, the survival rate of the Siamese fighting fish infected by A. hydrophila could be decreased by bathing with Indian almond red leaf extract at 750 ppm while green leaf Indian almond extract was effective for Aeromonad septicemia therapy in Siamese fighting fish when used at a concentration of 1,000 ppm. In conclusion, red leaf Indian almond aqueous extract had high potential for the control of pathogenic bacteria at a concentration of 750 ppm which should be safe for Siamese fighting fish taking into consideration the toxic level of the extract.

  19. Potential application of extracts from Indian almond (Terminalia catappa Linn.) leaves in Siamese fighting fish (Betta splendens Regan) culture.

    PubMed

    Purivirojkul, Watchariya

    2012-01-01

    almond leaf extract concentrations (6 concentrations) between the highest concentration that did not kill fish and the lowest concentration that killed all fish were used. Each concentration had three replicates (20 fish/replication). Mortality was observed after 96 hours. The LC50 value was calculated using probit analysis. The 96-h LC50 value for green and red leaf extracts was 1,765.69 and 1,651.21 ppm, respectively. When Siamese fighting fish were cultured in water added with Indian almond water extract at 5 concentrations for 5 days and then challenged with Aeromonas hydrophila at a concentration of 1 x 106 CFU/mL, the survival rate of the Siamese fighting fish infected by A. hydrophila could be decreased by bathing with Indian almond red leaf extract at 750 ppm while green leaf Indian almond extract was effective for Aeromonad septicemia therapy in Siamese fighting fish when used at a concentration of 1,000 ppm. In conclusion, red leaf Indian almond aqueous extract had high potential for the control of pathogenic bacteria at a concentration of 750 ppm which should be safe for Siamese fighting fish taking into consideration the toxic level of the extract. PMID:23885412

  20. The value of innovation under value-based pricing

    PubMed Central

    Moreno, Santiago G.; Ray, Joshua A.

    2016-01-01

    Objective The role of cost-effectiveness analysis (CEA) in incentivizing innovation is controversial. Critics of CEA argue that its use for pricing purposes disregards the ‘value of innovation’ reflected in new drug development, whereas supporters of CEA highlight that the value of innovation is already accounted for. Our objective in this article is to outline the limitations of the conventional CEA approach, while proposing an alternative method of evaluation that captures the value of innovation more accurately. Method The adoption of a new drug benefits present and future patients (with cost implications) for as long as the drug is part of clinical practice. Incidence patients and off-patent prices are identified as two key missing features preventing the conventional CEA approach from capturing 1) benefit to future patients and 2) future savings from off-patent prices. The proposed CEA approach incorporates these two features to derive the total lifetime value of an innovative drug (i.e., the value of innovation). Results The conventional CEA approach tends to underestimate the value of innovative drugs by disregarding the benefit to future patients and savings from off-patent prices. As a result, innovative drugs are underpriced, only allowing manufacturers to capture approximately 15% of the total value of innovation during the patent protection period. In addition to including the incidence population and off-patent price, the alternative approach proposes pricing new drugs by first negotiating the share of value of innovation to be appropriated by the manufacturer (>15%?) and payer (<85%?), in order to then identify the drug price that satisfies this condition. Conclusion We argue for a modification to the conventional CEA approach that integrates the total lifetime value of innovative drugs into CEA, by taking into account off-patent pricing and future patients. The proposed approach derives a price that allows manufacturers to capture an agreed share

  1. 40 CFR 799.4360 - Tributyl phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 522(a) and 1 CFR... value is ≤1 mg/L; or any fish or aquatic invertebrate EC50 or LC50 is ≤100 mg/L and either the rainbow... the following criteria: Any such value is ≤1 mg/L; or any fish or aquatic invertebrate EC50 or LC50...

  2. Teaching Values in the Schools.

    ERIC Educational Resources Information Center

    Baer, Richard A., Jr.

    1982-01-01

    Summarizes the major criticisms that have appeared in the literature and argues that values clarification should not be used in the public schools or by such quasi-public agencies as Scouts, Planned Parenthood, and 4-H. (JOW)

  3. ISO 14001 EMS VALUE PROPOSITION.

    SciTech Connect

    BRIGGS,S.L.K.

    2001-11-06

    The objective of this report is to identify business opportunities and value for Battelle Organizations to undertake IS0 14001 Environmental Management System Implementation and registration to the international standard as a corporate strategic initiative.

  4. Occupational Choice and Student Values

    ERIC Educational Resources Information Center

    McSweeney, R. V.

    1973-01-01

    Article attempts to set out a way of measuring determination, the element capable of making students' occupational choice' a reality not just an ideal, by exploration of the part played by the value system in relation to occupational choice. (Author)

  5. Values of The Cultural Revolution

    ERIC Educational Resources Information Center

    Wang, James C. F.

    1977-01-01

    Examines Chinese press editorials and testimonials from members of the People's Liberation Army in an attempt to determine the meaning of Mao Tse Tung's vision of a new socialist man and the societal value transformation process. (MH)

  6. Assessing value representation in animals.

    PubMed

    San-Galli, Aurore; Bouret, Sebastien

    2015-01-01

    Among all factors modulating our motivation to perform a given action, the ability to represent its outcome is clearly the most determining. Representation of outcomes, rewards in particular, and how they guide behavior, have sparked much research. Both practically and theoretically, understanding the relationship between the representation of outcome value and the organization of goal directed behavior implies that these two processes can be assessed independently. Most of animal studies essentially used instrumental actions as a proxy for the expected goal-value. The purpose of this article is to consider alternative measures of expected outcome value in animals, which are critical to understand the behavioral and neurobiological mechanisms relating the representation of the expected outcome to the organization of the behavior oriented towards its obtention. This would be critical in the field of decision making or social interactions, where the value of multiple items must often be compared and/or shared among individuals to determine the course of actions. PMID:25092260

  7. Assessing value representation in animals.

    PubMed

    San-Galli, Aurore; Bouret, Sebastien

    2015-01-01

    Among all factors modulating our motivation to perform a given action, the ability to represent its outcome is clearly the most determining. Representation of outcomes, rewards in particular, and how they guide behavior, have sparked much research. Both practically and theoretically, understanding the relationship between the representation of outcome value and the organization of goal directed behavior implies that these two processes can be assessed independently. Most of animal studies essentially used instrumental actions as a proxy for the expected goal-value. The purpose of this article is to consider alternative measures of expected outcome value in animals, which are critical to understand the behavioral and neurobiological mechanisms relating the representation of the expected outcome to the organization of the behavior oriented towards its obtention. This would be critical in the field of decision making or social interactions, where the value of multiple items must often be compared and/or shared among individuals to determine the course of actions.

  8. Diffusion technique stabilizes resistor values

    NASA Technical Reports Server (NTRS)

    Gallagher, R. C.; Giuliano, M. N.

    1966-01-01

    Reduction of the contact resistance stabilizes the values, over a broad temperature range, of resistors used in linear integrated circuits. This reduction is accomplished by p-plus diffusion under the alloyed aluminum contacts.

  9. Values From an Evolutionary Perspective

    ERIC Educational Resources Information Center

    Calhoun, John B.

    1972-01-01

    Continuation of life and evolution as criteria for development of a value system are analyzed. Discussion is based on an awareness aspect of evolution which promotes a greater harmony of response with existing and emerging environmental conditions. (BL)

  10. Histopathological alterations in the liver and intestine of Nile tilapia Oreochromis niloticus exposed to long-term sublethal concentrations of cadmium chloride

    NASA Astrophysics Data System (ADS)

    Younis, Elsayed; Abdel-Warith, Abdel-Wahab; Al-Asgah, Nasser; Ebaid, Hossam

    2015-07-01

    Fingerlings of Nile tilapia Oreochromis niloticus were exposed to 1.68, 3.36, and 5.04 mg/L cadmium (as CdCl2), which represent 10%, 20%, and 30% of their previously determined 96-h LC50. After exposure for 20 days, sections of the liver and intestine of treated fish were examined histologically. Histopathological changes varied from slight to severe structural modification, depending on the exposure concentration. The hepatic tissues of fish exposed to 10% LC50 showed markedly increased vacuolation of the hepatocytes and coarse granulation of their cytoplasm. Abundant erythrocytic infiltration among the hepatocytes was observed in fish exposed to 20% LC50. In the intestinal tissues of fish exposed to all doses, goblet cells proliferated and were greatly increased in size, the longitudinal muscularis mucosa was disturbed and, in the crypts of the sub-mucosal layer, apoptosis increased, indicated by large numbers of degenerated nuclei. Large numbers of inflammatory cells and dilated blood vessels were observed in the intestine of the group treated with 30% LC50.

  11. Public health and human values

    PubMed Central

    Häyry, M

    2006-01-01

    The ends and means of public health activities are suggested to be at odds with the values held by human individuals and communities. Although promoting longer lives in better health for all seems like an endeavour that is obviously acceptable, it can be challenged by equally self‐evident appeals to autonomy, happiness, integrity and liberty, among other values. The result is that people's actual concerns are not always adequately dealt with by public health measures and assurances. PMID:16943332

  12. A Child's World of Values.

    ERIC Educational Resources Information Center

    Mulcahy, Mary

    Children need to share their personal lives with other persons in a relationship of mutual respect and responsiveness; i.e., in a relationship of love. Children are an end, not a means, people to be valued for their own sakes. Adults must help children to know who they are and who they can become. Values contribute to the fulfillment of a person's…

  13. Clarifying values: an updated review

    PubMed Central

    2013-01-01

    Background Consensus guidelines have recommended that decision aids include a process for helping patients clarify their values. We sought to examine the theoretical and empirical evidence related to the use of values clarification methods in patient decision aids. Methods Building on the International Patient Decision Aid Standards (IPDAS) Collaboration’s 2005 review of values clarification methods in decision aids, we convened a multi-disciplinary expert group to examine key definitions, decision-making process theories, and empirical evidence about the effects of values clarification methods in decision aids. To summarize the current state of theory and evidence about the role of values clarification methods in decision aids, we undertook a process of evidence review and summary. Results Values clarification methods (VCMs) are best defined as methods to help patients think about the desirability of options or attributes of options within a specific decision context, in order to identify which option he/she prefers. Several decision making process theories were identified that can inform the design of values clarification methods, but no single “best” practice for how such methods should be constructed was determined. Our evidence review found that existing VCMs were used for a variety of different decisions, rarely referenced underlying theory for their design, but generally were well described in regard to their development process. Listing the pros and cons of a decision was the most common method used. The 13 trials that compared decision support with or without VCMs reached mixed results: some found that VCMs improved some decision-making processes, while others found no effect. Conclusions Values clarification methods may improve decision-making processes and potentially more distal outcomes. However, the small number of evaluations of VCMs and, where evaluations exist, the heterogeneity in outcome measures makes it difficult to determine their

  14. Theoretical value of psychological testing.

    PubMed

    Shapiro, David

    2012-01-01

    Apart from their diagnostic value, psychological tests, especially the Rorschach test, have an important theoretical value for understanding psychopathology. They present a picture of a living person, in contrast to a picture of forces and agencies within the person. This rests on 2 advantages of tests over the usual psychiatric and psychoanalytic interviews: Tests are ahistorical and they present information primarily of a formal kind.

  15. From value chain to value constellation: designing interactive strategy.

    PubMed

    Normann, R; Ramírez, R

    1993-01-01

    In today's fast-changing competitive environment, strategy is no longer a matter of positioning a fixed set of activities along that old industrial model, the value chain. Successful companies increasingly do not just add value, they reinvent it. The key strategic task is to reconfigure roles and relationships among a constellation of actors--suppliers, partners, customers--in order to mobilize the creation of value by new combinations of players. What is so different about this new logic of value? It breaks down the distinction between products and services and combines them into activity-based "offerings" from which customers can create value for themselves. But as potential offerings grow more complex, so do the relationships necessary to create them. As a result, a company's strategic task becomes the ongoing reconfiguration and integration of its competencies and customers. The authors provide three illustrations of these new rules of strategy. IKEA has blossomed into the world's largest retailer of home furnishings by redefining the relationships and organizational practices of the furniture business. Danish pharmacies and their national association have used the opportunity of health care reform to reconfigure their relationships with customers, doctors, hospitals, drug manufacturers, and with Danish and international health organizations to enlarge their role, competencies, and profits. French public-service concessionaires have mastered the art of conducting a creative dialogue between their customers--local governments in France and around the world--and a perpetually expanding set of infrastructure competencies. PMID:10127040

  16. The relative value of growth.

    PubMed

    Mass, Nathaniel J

    2005-04-01

    Most executives would say that adding a point of growth and gaining a point of operating-profit margin contribute about equally to shareholder value. Margin improvements hit the bottom line immediately, while growth compounds value over time. But the reality is that the two are rarely equivalent. Growth often is far more valuable than managers think. For some companies, convincing the market that they can grow by just one additional percentage point can be worth six, seven, or even ten points of margin improvement. This article presents a new strategic metric, called the relative value of growth (RVG), which gives managers a clear picture of how growth projects and margin improvement initiatives affect shareholder value. Using basic balance sheet and income sheet data, managers can determine their companies' RVGs, as well as those of their competitors. Calculating RVGs gives managers insights into which corporate strategies are working to deliver value and whether their companies are pulling the most powerful value-creation levers. The author examines a number of well-known companies and explains what their RVG numbers say about their strategies. He reviews the unspoken assumption that growth and profits are incompatible over the long term and shows that a fair number of companies are effective at delivering both. Finally, he explains how managers can use the RVG framework to help them define strategies that balance growth and profitability at both the corporate and business unit levels.

  17. Local variation in susceptibility of Colorado potato beetle (Coleoptera: Chrysomelidae) to insecticide.

    PubMed

    Pourmirza, Ali Asghr

    2005-12-01

    The susceptibility status of Colorado potato beetle, Leptinotarsa decemlineata (Say), adults to phosalone was determined by dip and glass jar assay techniques. Bioassay results indicated a narrow variation in Colorado potato beetle insecticide susceptibility among sample sites. LC50 values were generally highest from specimens collected in field that received frequent phosalone applications for seven consecutive growing seasons. In five populations tested, LC50 values ranged from 503.72 to 827.95 ppm in dip test method. In glass jar technique, resistance ratio value of 1.72 for LC50 was obtained. A significant linear relationship between LC50 values of individual populations across test methods was detected. Both bioassay techniques were suitable for monitoring resistance to insecticide in Colorado potato beetle adult populations. Glass jar technique, however, exhibited less variability in LC50 estimates and showed a higher degree of sensitivity than the dip method. Filter paper and leaf disk techniques for larvae were two bioassay methods used to determine phosalone susceptibility in L. decemlineata populations. Both bioassay techniques exhibited a similar level of susceptibility of the larvae to phosalone; however, the fiducial limit values from filter paper method were narrow than the leaf disk assay technique. A significant direct relationship between LC50 values of individual population across test methods was observed. Differences in LC50 ranking among fields between adults and larvae indicated a differential susceptibility to insecticide between life stages. Low LC50 values obtained from Colorado potato beetle in sample sites indicated that phosalone resistance was not severe in these fields. The glass jar and filter paper testing methods are simple and sensitive test techniques for measuring susceptibility of Colorado potato beetle adults and larvae to phosalone, respectively.

  18. Likely values of the Higgs vacuum expectation value

    SciTech Connect

    Donoghue, John F.; Dutta, Koushik; Ross, Andreas; Tegmark, Max

    2010-04-01

    We make an estimate of the likelihood function for the Higgs vacuum expectation value (vev) by imposing anthropic constraints on the existence of atoms while allowing the other parameters of the standard model to also be variable. We argue that the most important extra ingredients are the Yukawa couplings, and for the intrinsic distribution of Yukawa couplings we use the scale-invariant distribution which is favored phenomenologically. The result is successful phenomenologically, favoring values close to the observed vev. We also discuss modifications that can change these conclusions. Our work supports the hypothesis that the anthropic constraints could be the origin of the small Higgs vev.

  19. Effects of selenium on development, survival, and accumulation in the honeybee (Apis mellifera L.).

    PubMed

    Hladun, Kristen R; Kaftanoglu, Osman; Parker, David R; Tran, Khoa D; Trumble, John T

    2013-11-01

    Apis mellifera L. (Hymenoptera: Apidae) is an important agricultural pollinator in the United States and throughout the world. In areas of selenium (Se) contamination, honeybees may be at risk because of the biotransfer of Se from plant products such as nectar and pollen. Several forms of Se can occur in accumulating plants. In the present study, the toxicity of 4 compounds (selenate, selenite, methylselenocysteine, and selenocystine) to honeybee adult foragers and larvae was assessed using dose-response bioassays. Inorganic forms were more toxic than organic forms for both larvae (lethal concentration [LC50] selenate = 0.72 mg L(-1) , LC50 selenite = 1.0 mg L(-1) , LC50 methylselenocysteine = 4.7 mg L(-1) , LC50 selenocystine = 4.4 mg L(-1) ) and foragers (LC50 selenate = 58 mg L(-1) , LC50 selenite = 58 mg L(-1) , LC50 methylselenocysteine = 161 mg L(-1) , LC50 selenocystine = 148 mg L(-1) ). Inorganic forms of Se caused rapid mortality, and organic forms had sublethal effects on development. Larvae accumulated substantial amounts of Se only at the highest doses, whereas foragers accumulated large quantities at all doses. The present study documented very low larval LC50 values for Se; even modest transfer to brood will likely cause increased development times and mortality. The toxicities of the various forms of Se to honeybee larvae and foragers are discussed in comparison with other insect herbivores and detritivores.

  20. Acute toxicity of copper, lead, cadmium, and zinc to early life stages of white sturgeon (Acipenser transmontanus) in laboratory and Columbia River water.

    PubMed

    Vardy, David W; Santore, Robert; Ryan, Adam; Giesy, John P; Hecker, Markus

    2014-01-01

    Populations of white sturgeon (Acipenser transmontanus) are in decline in North America. This is attributed, primarily, to poor recruitment, and white sturgeon are listed as threatened or endangered in several parts of British Columbia, Canada, and the United States. In the Columbia River, effects of metals have been hypothesized as possible contributing factors. Previous work has demonstrated that early life stage white sturgeon are particularly sensitive to certain metals, and concerns over the level of protectiveness of water quality standards are justified. Here we report results from acute (96-h) toxicity tests for copper (Cu), cadmium (Cd), zinc (Zn), and lead (Pb) from parallel studies that were conducted in laboratory water and in the field with Columbia River water. Water effect ratios (WERs) and sensitivity parameters (i.e., median lethal accumulations, or LA50s) were calculated to assess relative bioavailability of these metals in Columbia River water compared to laboratory water, and to elucidate possible differences in sensitivity of early life stage white sturgeon to the same concentrations of metals when tested in the different water sources. For Cu and Pb, white sturgeon toxicity tests were initiated at two life stages, 8 and 40 days post-hatch (dph), and median lethal concentrations (LC50s) ranged between 9-25 μg Cu/L and 177-1,556 μg Pb/L. LC50s for 8 dph white sturgeon exposed to Cd in laboratory water and river water were 14.5 and 72 μg/L, respectively. Exposure of 8 dph white sturgeon to Zn in laboratory and river water resulted in LC50s of 150 and 625 μg/L, respectively. Threshold concentrations were consistently less in laboratory water compared with river water, and as a result, WERs were greater than 1 in all cases. In addition, LA50s were consistently greater in river water exposures compared with laboratory exposures in all paired tests. These results, in combination with results from the biotic ligand model, suggest that the observed

  1. Transporting values by technology transfer.

    PubMed

    De Castro, Leonardo D

    1997-01-01

    The introduction of new medical technologies into a developing country is usually greeted with enthusiasm as the possible benefits become an object of great anticipation and provide new hope for therapy or relief. The prompt utilization of new discoveries and inventions by a medical practitioner serves as a positive indicator of high standing in the professional community. But the transfer of medical technology also involves a transfer of concomitant values. There is a danger that, in the process of adopting a particular technology, the user takes for granted the general utility and desirability of the implements and procedures under consideration without recognizing the socio-cultural peculiarities of the adopting country. A sensitivity to the social conditions and cultural traditions is important so that the emergence of new values can be examined critically and the transfer of necessary technology can be effected smoothly. In the Philippines, efforts to boost patronage of transplant technology appear to have overlooked this need for socio-cultural sensitivity. Legislative fiat cannot be used to override deep-seated values. There is a need to be more sensitive to the possible confrontation of values that the transfer of technology brings in order to avoid the erosion of indigenous socio-cultural values and minimize the intrusiveness of beneficial medical technology.

  2. Education for values and bioethics.

    PubMed

    Nunes, Rui; Duarte, Ivone; Santos, Cristina; Rego, Guilhermina

    2015-01-01

    "Education for Values and Bioethics" is a project which aims to help the student to build his/her personal ethics. It was addressed to ninth grade students (mean age 14) who frequented public education in all schools of the City of Porto, Portugal-EU in 2010-2013 (N-1164). This research and action project intended to promote the acquisition of knowledge in the following areas: interpersonal relationships, human rights, responsible sexuality, health, environment and sustainable development, preservation of public property, culture, financial education, social innovation and ethical education for work. The students were asked to answer to a knowledge questionnaire on bioethics. To assess the values it was used Leonard Gordon's Survey of Personal Values and Survey of Interpersonal Values. The results of this study show that the project contributes to an increase of knowledge in the area of bioethics. Also the students enrolled in the program showed a development with regards the acquisition of the basic values of pluralistic societies. It is also suggested that this general knowledge on bioethics could be especially helpful to students that want a career in health sciences. PMID:25694860

  3. Capacity Value of Wind Power

    SciTech Connect

    Keane, Andrew; Milligan, Michael; Dent, Chris; Hasche, Bernhard; DAnnunzio, Claudine; Dragoon, Ken; Holttinen, Hannele; Samaan, Nader A.; Soder, Lennart; O'Malley, Mark J.

    2011-05-04

    Power systems are planned such that they have adequate generation capacity to meet the load, according to a defined reliability target. The increase in the penetration of wind generation in recent years has led to a number of challenges for the planning and operation of power systems. A key metric for system adequacy is the capacity value of generation. The capacity value of a generator is the contribution that a given generator makes to overall system adequacy. The variable and stochastic nature of wind sets it apart from conventional energy sources. As a result, the modeling of wind generation in the same manner as conventional generation for capacity value calculations is inappropriate. In this paper a preferred method for calculation of the capacity value of wind is described and a discussion of the pertinent issues surrounding it is given. Approximate methods for the calculation are also described with their limitations highlighted. The outcome of recent wind capacity value analyses in Europe and North America are highlighted with a description of open research questions also given.

  4. Active inference and epistemic value.

    PubMed

    Friston, Karl; Rigoli, Francesco; Ognibene, Dimitri; Mathys, Christoph; Fitzgerald, Thomas; Pezzulo, Giovanni

    2015-01-01

    We offer a formal treatment of choice behavior based on the premise that agents minimize the expected free energy of future outcomes. Crucially, the negative free energy or quality of a policy can be decomposed into extrinsic and epistemic (or intrinsic) value. Minimizing expected free energy is therefore equivalent to maximizing extrinsic value or expected utility (defined in terms of prior preferences or goals), while maximizing information gain or intrinsic value (or reducing uncertainty about the causes of valuable outcomes). The resulting scheme resolves the exploration-exploitation dilemma: Epistemic value is maximized until there is no further information gain, after which exploitation is assured through maximization of extrinsic value. This is formally consistent with the Infomax principle, generalizing formulations of active vision based upon salience (Bayesian surprise) and optimal decisions based on expected utility and risk-sensitive (Kullback-Leibler) control. Furthermore, as with previous active inference formulations of discrete (Markovian) problems, ad hoc softmax parameters become the expected (Bayes-optimal) precision of beliefs about, or confidence in, policies. This article focuses on the basic theory, illustrating the ideas with simulations. A key aspect of these simulations is the similarity between precision updates and dopaminergic discharges observed in conditioning paradigms. PMID:25689102

  5. Applied extreme-value statistics

    SciTech Connect

    Kinnison, R.R.

    1983-05-01

    The statistical theory of extreme values is a well established part of theoretical statistics. Unfortunately, it is seldom part of applied statistics and is infrequently a part of statistical curricula except in advanced studies programs. This has resulted in the impression that it is difficult to understand and not of practical value. In recent environmental and pollution literature, several short articles have appeared with the purpose of documenting all that is necessary for the practical application of extreme value theory to field problems (for example, Roberts, 1979). These articles are so concise that only a statistician can recognise all the subtleties and assumptions necessary for the correct use of the material presented. The intent of this text is to expand upon several recent articles, and to provide the necessary statistical background so that the non-statistician scientist can recognize and extreme value problem when it occurs in his work, be confident in handling simple extreme value problems himself, and know when the problem is statistically beyond his capabilities and requires consultation.

  6. New reference values for calcium.

    PubMed

    2013-01-01

    The nutrition societies of Germany, Austria and Switzerland are the joint editors of the 'reference values for nutrient intake'. They have revised the reference values for the intake of calcium and published them in June 2013. The reference values for the calcium intake for infants are derived from the calcium content of breast milk. For infants from 4 to <12 months of age, the calcium intake from solid foods is included in addition to the calcium intake from breast milk. Thus, the reference values for infants are estimated values; they are 220 mg/day for infants to <4 months and 330 mg/day for infants from 4 to <12 months of age. As a parameter for determining the calcium requirement in children and adolescents, calcium retention is taken into account. The average requirement is calculated by the factorial method. A balanced calcium metabolism is calculated based upon calcium balance studies and used as a parameter for the determination of the calcium requirement in adults. On the basis of the average requirement, recommended calcium intake levels for children, adolescents and adults are derived. Depending on age, the recommended calcium intake ranges between 600 mg/day for children aged 1 to <4 years and 1,200 mg/day for adolescents aged 13 to <19 years; for adults, it is 1,000 mg/day. PMID:24356454

  7. Being of Value: Intentionally Fostering and Documenting Public Value

    ERIC Educational Resources Information Center

    Dierking, Lynn D.

    2010-01-01

    The discussion of public value is in the air among museums and other cultural institutions as they strive to achieve strategic impact "for and with" their "communities," rather than merely operational impact "for themselves." At the most basic level, it is about ensuring that their work is fully and meaningfully connected to the fabric and true…

  8. Can Value Added Add Value to Teacher Evaluation?

    ERIC Educational Resources Information Center

    Darling-Hammond, Linda

    2015-01-01

    The five thoughtful papers included in this issue of "Educational Researcher" ("ER") raise new questions about the use of value-added methods (VAMs) to estimate teachers' contributions to students' learning as part of personnel evaluation. The papers address both technical and implementation concerns, considering potential…

  9. What's the Value of VAM (Value-Added Modeling)?

    ERIC Educational Resources Information Center

    Scherrer, Jimmy

    2012-01-01

    The use of value-added modeling (VAM) in school accountability is expanding, but deciding how to embrace VAM is difficult. Various experts say it's too unreliable, causes more harm than good, and has a big margin for error. Others assert VAM is imperfect but useful, and provides valuable feedback. A closer look at the models, and their use,…

  10. The Value in Value Added Depends on the Ecology

    ERIC Educational Resources Information Center

    Braun, Henry

    2015-01-01

    In this commentary, the author states that, as the contributions of the focal articles make clear, there is much to learn about how value-added models (VAMs) are actually used in a variety of settings. Indeed, it is important to remember that VAM scores are but one component of a complex evaluation system that can play out differently in different…

  11. Professional values, aesthetic values, and the ends of trade.

    PubMed

    Edgar, Andrew

    2011-05-01

    Professionalism is initially understood as a historical process, through which certain commercial services sought to improve their social status (and economic reward) by separating themselves from mere crafts or trades. This process may be traced clearly with the aspiration of British portrait painters (headed by Sir Joshua Reynolds), in the eighteenth century, to acquire a social status akin to that of already established professionals, such as clerics and doctors. This may be understood, to a significant degree, as a process of gentrification. The values of the professional thereby lie as much in the etiquette and other social skills with which they deal with their clients, than with any distinctive form of skill or value. Professionalisation as gentrification seemingly says little about the nature of modern professionalism. However, if this process is also construed as one in which the goals and achievements of the profession come to be subject to radical reflection, then something significant about professional values emerges. On this account, the profession is distinguished from craft or trade on the grounds that the goals of the profession, and the effectiveness of any attempt to realise them, are not transparent to the client. While a lay person will typically have the competence necessary to judge whether or not a craft worker has achieved their goal, that person will not necessarily be able to recognise the values that determine the success of a medical operation. It will be concluded that the values of a profession are articulated intrinsically to the profession, in terms of the contested understanding that the professionals themselves have of the meaning of the profession and the narratives within which its history is to be told.

  12. Professional values, aesthetic values, and the ends of trade.

    PubMed

    Edgar, Andrew

    2011-05-01

    Professionalism is initially understood as a historical process, through which certain commercial services sought to improve their social status (and economic reward) by separating themselves from mere crafts or trades. This process may be traced clearly with the aspiration of British portrait painters (headed by Sir Joshua Reynolds), in the eighteenth century, to acquire a social status akin to that of already established professionals, such as clerics and doctors. This may be understood, to a significant degree, as a process of gentrification. The values of the professional thereby lie as much in the etiquette and other social skills with which they deal with their clients, than with any distinctive form of skill or value. Professionalisation as gentrification seemingly says little about the nature of modern professionalism. However, if this process is also construed as one in which the goals and achievements of the profession come to be subject to radical reflection, then something significant about professional values emerges. On this account, the profession is distinguished from craft or trade on the grounds that the goals of the profession, and the effectiveness of any attempt to realise them, are not transparent to the client. While a lay person will typically have the competence necessary to judge whether or not a craft worker has achieved their goal, that person will not necessarily be able to recognise the values that determine the success of a medical operation. It will be concluded that the values of a profession are articulated intrinsically to the profession, in terms of the contested understanding that the professionals themselves have of the meaning of the profession and the narratives within which its history is to be told. PMID:21063909

  13. Re-valuing the amygdala

    PubMed Central

    Morrison, Sara E.; Salzman, C. Daniel

    2010-01-01

    Summary Recent advances indicate that the amygdala represents valence: a general appetitive/aversive affective characteristic that bears similarity to the neuroeconomic concept of value. Neurophysiological studies show that individual amygdala neurons respond differentially to a range of stimuli with positive or negative affective significance. Meanwhile, increasingly specific lesion/inactivation studies reveal that the amygdala is necessary for processes – e.g., fear extinction and reinforcer devaluation – that involve updating representations of value. Furthermore, recent neuroimaging studies suggest that the human amygdala mediates performance on many reward-based decision-making tasks. The encoding of affective significance by the amygdala might be best described as a representation of state value – a representation that is useful for coordinating physiological, behavioral, and cognitive responses in an affective/emotional context. PMID:20299204

  14. The Value Question in Metaphysics.

    PubMed

    Kahane, Guy

    2012-07-01

    Much seems to be at stake in metaphysical questions about, for example, God, free will or morality. One thing that could be at stake is the value of the universe we inhabit-how good or bad it is. We can think of competing philosophical positions as describing possibilities, ways the world might turn out to be, and to which value can be assigned. When, for example, people hope that God exists, or fear that we do not possess free will, they express attitudes towards these possibilities, attitudes that presuppose answers to questions about their comparative value. My aim in this paper is to distinguish these evaluative questions from related questions with which they can be confused, to identify structural constraints on their proper pursuit, and to address objections to their very coherence. Answers to such evaluative questions offer one measure of the importance of philosophical disputes.

  15. Interpretative reports and critical values.

    PubMed

    Piva, Elisa; Plebani, Mario

    2009-06-01

    In the clinical laboratory to allow an effective testing process, post-analytical activity can have two goals in trying to improve patient safety: result interpretation and communication of critical values. Both are important issues, and their success requires a cooperative effort. Misinterpretation of laboratory test results or ineffectiveness in their notification can lead to diagnostic errors or errors in identifying patient critical conditions. With the awareness that the incorrect interpretation of tests and the breakdown in the communication of critical values are preventable errors, laboratorians should make every effort to prevent the types of errors that potentially harm patients. In order to improve the reliability of laboratories, we attempt to explain how interpretative reporting and automated notification of critical values can be used to reduce errors. Clinical laboratories can therefore work to improve clinical effectiveness, without forgetting that everything should be designed to provide the best outcomes for patients.

  16. The Value Question in Metaphysics

    PubMed Central

    Kahane, Guy

    2012-01-01

    Much seems to be at stake in metaphysical questions about, for example, God, free will or morality. One thing that could be at stake is the value of the universe we inhabit—how good or bad it is. We can think of competing philosophical positions as describing possibilities, ways the world might turn out to be, and to which value can be assigned. When, for example, people hope that God exists, or fear that we do not possess free will, they express attitudes towards these possibilities, attitudes that presuppose answers to questions about their comparative value. My aim in this paper is to distinguish these evaluative questions from related questions with which they can be confused, to identify structural constraints on their proper pursuit, and to address objections to their very coherence. Answers to such evaluative questions offer one measure of the importance of philosophical disputes. PMID:23024399

  17. Median lethal concentration of formaldehyde and its genotoxic potential in bullfrog tadpoles (Lithobates catesbeianus).

    PubMed

    Santana, Juliana M; Dos Reis, Adriana; Teixeira, Patrícia C; Ferreira, Fábio C; Ferreira, Cláudia M

    2015-01-01

    In order to avoid that contaminated frog farms animals escaping in the environment and become potential vector of emergent diseases, studies with disinfection protocol are strictly necessary. The formaldehyde is one of the compounds tested in fungal disinfection protocols and also used in aquaculture. This study aimed to determine the median lethal concentration (LC50-96h) of formaldehyde in bullfrog tadpoles and to evaluate the possible genotoxic effects in acute exposition. Accordingly, the animals were exposed to formaldehyde in the concentrations of 6, 9, 12, 15, and 18 mg L(-1), and after 96 h blood samples were drawn for the micronucleus (MN) test. The LC50-96h was 10.53 mg L(-1), and the MN frequency increased in proportion to the formaldehyde concentrations, with an estimated frequency in the negative control being 1.35 MN/individual. We concluded that formaldehyde is genotoxic to tadpoles of bullfrogs in the tested concentrations, and the choice of this chemical should be contemplated before its use in animals in captivity.

  18. Effects of ammonia on juvenile unionid mussels (Lampsilis cardium) in laboratory sediment toxicity tests

    USGS Publications Warehouse

    Newton, Teresa J.; Allran, John W.; O'Donnell, Jonathan A.; Bartsch, Michelle; Richardson, William B.

    2003-01-01

    Ammonia is a relatively toxic compound generated in water and sediments by heterotrophic bacteria and accumulates in sediments and pore water. Recent data suggest that unionid mussels are sensitive to un-ionized ammonia (NH3) relative to other organisms. Existing sediment exposure systems are not suitable for ammonia toxicity studies with juvenile unionids; thus, we modified a system to expose juveniles to ammonia that was continuously infused into sediments. This system maintained consistent concentrations of ammonia in pore water up to 10 d. Juvenile Lampsilis cardium mussels were exposed to NH3 in pore water in replicate 96-h and 10-d sediment toxicity tests. The 96-h median lethal concentrations (LC50s) were 127 and 165 μg NH3-N/L, and the 10-d LC50s were 93 and 140 μg NH3-N/L. The median effective concentrations (EC50s) (based on the proportion affected, including dead and inactive mussels) were 73 and 119 μg NH3-N/L in the 96-h tests and 71 and 99 μg NH3-N/L in the 10-d tests. Growth rate was substantially reduced at concentrations between 31 and 76 μg NH3-N/L. The lethality results (when expressed as total ammonia) are about one-half the acute national water quality criteria for total ammonia, suggesting that existing criteria may not protect juvenile unionids.

  19. Effect of starving and feeding on some haematological and physiological responses of the Nile catfish, Clarias gariepinus exposed to copper at extreme seasons.

    PubMed

    Abdel-Hameid, Nassr-Allah H

    2011-12-01

    The lethal concentration for 50% of fish for 96h (96h LC(50)) of copper (Cu(2+)) was estimated for the Nile catfish (Clarias gariepinus) in extreme seasons, winter and summer, 4.31 and 4.79 mg/l, respectively. The Nile catfish was exposed to 96h LC(50) of copper for 7 days in extreme winter and summer. The body indices, haematological parameters as well as some plasma and liver enzyme activities and metabolite level were significantly differed in fish exposed to copper over than those of the control fish. Most of the tested parameters were not significantly different between the control fish of winter and summer (winter, water temperature 18 ± 2°C and summer, 27 ± 2°C). The effect of two ration sizes on copper toxicity in two different seasons on C. gariepinus was justified. It was found that the haematological parameters and the tested plasma activities of enzymes were significantly valid due to season differences. The blood parameters as well as plasma activities of enzymes were significantly differed in fishes fed elevated ration (3%) and exposed to copper challenge. On the other hand, the exploit of low feeding ration (0.5%) along with copper exposure during the examined seasons induced non-significant differences of the tested parameters, from those of the corresponding control. Therefore, the low feeding ration provides some tolerance against the possible water-borne copper exposure.

  20. Median lethal concentration of formaldehyde and its genotoxic potential in bullfrog tadpoles (Lithobates catesbeianus).

    PubMed

    Santana, Juliana M; Dos Reis, Adriana; Teixeira, Patrícia C; Ferreira, Fábio C; Ferreira, Cláudia M

    2015-01-01

    In order to avoid that contaminated frog farms animals escaping in the environment and become potential vector of emergent diseases, studies with disinfection protocol are strictly necessary. The formaldehyde is one of the compounds tested in fungal disinfection protocols and also used in aquaculture. This study aimed to determine the median lethal concentration (LC50-96h) of formaldehyde in bullfrog tadpoles and to evaluate the possible genotoxic effects in acute exposition. Accordingly, the animals were exposed to formaldehyde in the concentrations of 6, 9, 12, 15, and 18 mg L(-1), and after 96 h blood samples were drawn for the micronucleus (MN) test. The LC50-96h was 10.53 mg L(-1), and the MN frequency increased in proportion to the formaldehyde concentrations, with an estimated frequency in the negative control being 1.35 MN/individual. We concluded that formaldehyde is genotoxic to tadpoles of bullfrogs in the tested concentrations, and the choice of this chemical should be contemplated before its use in animals in captivity. PMID:26266476

  1. Extreme value analysis in biometrics.

    PubMed

    Hüsler, Jürg

    2009-04-01

    We review some approaches of extreme value analysis in the context of biometrical applications. The classical extreme value analysis is based on iid random variables. Two different general methods are applied, which will be discussed together with biometrical examples. Different estimation, testing, goodness-of-fit procedures for applications are discussed. Furthermore, some non-classical situations are considered where the data are possibly dependent, where a non-stationary behavior is observed in the data or where the observations are not univariate. A few open problems are also stated.

  2. Weak value amplification considered harmful

    NASA Astrophysics Data System (ADS)

    Ferrie, Christopher; Combes, Joshua

    2014-03-01

    We show using statistically rigorous arguments that the technique of weak value amplification does not perform better than standard statistical techniques for the tasks of parameter estimation and signal detection. We show that using all data and considering the joint distribution of all measurement outcomes yields the optimal estimator. Moreover, we show estimation using the maximum likelihood technique with weak values as small as possible produces better performance for quantum metrology. In doing so, we identify the optimal experimental arrangement to be the one which reveals the maximal eigenvalue of the square of system observables. We also show these conclusions do not change in the presence of technical noise.

  3. Multifractal Value at Risk model

    NASA Astrophysics Data System (ADS)

    Lee, Hojin; Song, Jae Wook; Chang, Woojin

    2016-06-01

    In this paper new Value at Risk (VaR) model is proposed and investigated. We consider the multifractal property of financial time series and develop a multifractal Value at Risk (MFVaR). MFVaR introduced in this paper is analytically tractable and not based on simulation. Empirical study showed that MFVaR can provide the more stable and accurate forecasting performance in volatile financial markets where large loss can be incurred. This implies that our multifractal VaR works well for the risk measurement of extreme credit events.

  4. Thoughts on Earned Value Assessments

    NASA Technical Reports Server (NTRS)

    Pido, Kelle

    2009-01-01

    This slide presentation reviews the concepts of Earned Value reporting and Earned Value Metrics (EVM) and the implementation for the Constellation Program. EVM is used to manage both the contract and civil service workforce, and used as a measure of contractor costs and performance. The Program EVM is not as useful for Level of Effort tasking, for either contractor, or civil service employees. Some issues and concerns in reference to EVM and the process for the use of EVM for Mission assurance are reviewed,

  5. Studies on the Development of Potential Biomarkers for Rapid Assessment of Copper Toxicity to Freshwater Fish using Esomus danricus as Model

    PubMed Central

    Vutukuru, S. S.; Suma, Ch.; Madhavi, K. Radha; Juveria; Pauleena, J. Smitha; Rao, J. Venkateswara; Anjaneyulu, Y.

    2005-01-01

    Living in an environment that has been altered considerably by anthropogenic activities, fish are often exposed to a multitude of stressors including heavy metals. Copper ions are quite toxic to fish when concentrations are increased in environmental exposures often resulting in physiological, histological, biochemical and enzymatic alterations in fish, which have a great potential to serve as biomarkers. Esomus danricus was chosen as model in the present study and the metabolic rate, gill morphology, total glycogen, total protein, superoxide dismutase and catalase were critically evaluated. The 96h LC50 value was found to be 5.5mg/L (Cu as 1.402mg/L). Fish groups were separately exposed to lethal (5.5mg/L) and sub lethal concentrations (0.55 mg/L) of copper sulphate over a period of 96h to examine the subtle effects caused at various functional levels. Controls were also maintained simultaneously. Significant decrease in the metabolic rate (p<0.001) of the fish was observed in both the concentrations studied. Studies employing Automated Video Tracking System revealed gross changes in the architecture of gill morphology like loss, fusion, clubbing of secondary gill lamellae, and detachment of gill rakers following softening of gill shaft in fish under lethal exposures indicating reduced respiratory surface area. Biochemical profiles like total glycogen and total protein in gills and muscle of fish exposed to 5.5 mg/L showed appreciable decrease (p<0.05 to 0.001) from control. Significant inhibition of superoxide dismutase (60.83%), catalase (71.57%) from control was observed in fish exposed to 5.5 mg/L at the end of 96h exposure only. Interestingly, in fish exposed to 0.55 mg/L enzyme activity is not affected except for catalase. Toxic responses evaluated at various functional levels are more pronounced in fish exposed to 5.5mg/L and these can serve as potential biomarkers for rapid assessment of acute copper toxicity in environmental biomonitoring. PMID:16705802

  6. A system for conducting flow-through toxicity tests with larval fish

    SciTech Connect

    Diamond, S.A.; Oris, J.T.; Guttman, S.I.

    1995-08-01

    Assessment of toxicological effects in aquatic systems commonly include larval fish 96-h LC50 determinations. The LC50 tests are conducted using static renewal as well as flow-through methods. However, in the case of chemicals with high vapor pressures or fugacity, static renewal methods may produce inconsistent results arising from the pulsed nature of exposure. In addition, in exposures involving these types of compounds, the fluctuation in concentration that can occur between renewals is unlike most exposure scenarios in nature. For these reasons, flow-through systems are often preferable. The authors report here on an inexpensive, easily constructed, flow-through system for toxicant exposure of small organisms. Data are presented to illustrate the capacity of the system to maintain uniform toxicant concentrations relative to static renewal methods.

  7. An evaluation of the influence of substrate on the response of juvenile freshwater mussels (fatmucket, Lampsilis siliquoidea) in acute water exposures to ammonia

    USGS Publications Warehouse

    Miao, J.; Barnhart, M.C.; Brunson, E.L.; Hardesty, D.K.; Ingersoll, C.G.; Wang, N.

    2010-01-01

    Acute 96-h ammonia toxicity to three-month-old juvenile mussels (Lampsilis siliquoidea) was evaluated in four treatments (water-only, water-only with feeding, water and soil, and water and sand) using an exposure unit designed to maintain consistent pH and ammonia concentrations in overlying water and in pore water surrounding the substrates. Median effect concentrations (EC50s) for total ammonia nitrogen in the four treatments ranged from 5.6 to 7.7mg/L and median lethal concentrations (LC50s) ranged from 7.0 to 11mg/L at a mean pH of 8.4. Similar EC50s or LC50s with overlapping 95% confidence intervals among treatments indicated no influence of substrate on the response of mussels in acute exposures to ammonia. ?? 2010 SETAC.

  8. Cassava Breeding I: The Value of Breeding Value

    PubMed Central

    Ceballos, Hernán; Pérez, Juan C.; Joaqui Barandica, Orlando; Lenis, Jorge I.; Morante, Nelson; Calle, Fernando; Pino, Lizbeth; Hershey, Clair H.

    2016-01-01

    Breeding cassava relies on several selection stages (single row trial-SRT; preliminary; advanced; and uniform yield trials—UYT). This study uses data from 14 years of evaluations. From more than 20,000 genotypes initially evaluated only 114 reached the last stage. The objective was to assess how the data at SRT could be used to predict the probabilities of genotypes reaching the UYT. Phenotypic data from each genotype at SRT was integrated into the selection index (SIN) used by the cassava breeding program. Average SIN from all the progenies derived from each progenitor was then obtained. Average SIN is an approximation of the breeding value of each progenitor. Data clearly suggested that some genotypes were better progenitors than others (e.g., high number of their progenies reaching the UYT), suggesting important variation in breeding values of progenitors. However, regression of average SIN of each parental genotype on the number of their respective progenies reaching UYT resulted in a negligible coefficient of determination (r2 = 0.05). Breeding value (e.g., average SIN) at SRT was not efficient predicting which genotypes were more likely to reach the UYT stage. Number of families and progenies derived from a given progenitor were more efficient predicting the probabilities of the progeny from a given parent reaching the UYT stage. Large within-family genetic variation tends to mask the true breeding value of each progenitor. The use of partially inbred progenitors (e.g., S1 or S2 genotypes) would reduce the within-family genetic variation thus making the assessment of breeding value more accurate. Moreover, partial inbreeding of progenitors can improve the breeding value of the original (S0) parental material and sharply accelerate genetic gains. For instance, homozygous S1 genotypes for the dominant resistance to cassava mosaic disease (CMD) could be generated and selected. All gametes from these selected S1 genotypes would carry the desirable allele and

  9. Cassava Breeding I: The Value of Breeding Value.

    PubMed

    Ceballos, Hernán; Pérez, Juan C; Joaqui Barandica, Orlando; Lenis, Jorge I; Morante, Nelson; Calle, Fernando; Pino, Lizbeth; Hershey, Clair H

    2016-01-01

    Breeding cassava relies on several selection stages (single row trial-SRT; preliminary; advanced; and uniform yield trials-UYT). This study uses data from 14 years of evaluations. From more than 20,000 genotypes initially evaluated only 114 reached the last stage. The objective was to assess how the data at SRT could be used to predict the probabilities of genotypes reaching the UYT. Phenotypic data from each genotype at SRT was integrated into the selection index (SIN) used by the cassava breeding program. Average SIN from all the progenies derived from each progenitor was then obtained. Average SIN is an approximation of the breeding value of each progenitor. Data clearly suggested that some genotypes were better progenitors than others (e.g., high number of their progenies reaching the UYT), suggesting important variation in breeding values of progenitors. However, regression of average SIN of each parental genotype on the number of their respective progenies reaching UYT resulted in a negligible coefficient of determination (r (2) = 0.05). Breeding value (e.g., average SIN) at SRT was not efficient predicting which genotypes were more likely to reach the UYT stage. Number of families and progenies derived from a given progenitor were more efficient predicting the probabilities of the progeny from a given parent reaching the UYT stage. Large within-family genetic variation tends to mask the true breeding value of each progenitor. The use of partially inbred progenitors (e.g., S1 or S2 genotypes) would reduce the within-family genetic variation thus making the assessment of breeding value more accurate. Moreover, partial inbreeding of progenitors can improve the breeding value of the original (S0) parental material and sharply accelerate genetic gains. For instance, homozygous S1 genotypes for the dominant resistance to cassava mosaic disease (CMD) could be generated and selected. All gametes from these selected S1 genotypes would carry the desirable allele and

  10. Cassava Breeding I: The Value of Breeding Value

    PubMed Central

    Ceballos, Hernán; Pérez, Juan C.; Joaqui Barandica, Orlando; Lenis, Jorge I.; Morante, Nelson; Calle, Fernando; Pino, Lizbeth; Hershey, Clair H.

    2016-01-01

    Breeding cassava relies on several selection stages (single row trial-SRT; preliminary; advanced; and uniform yield trials—UYT). This study uses data from 14 years of evaluations. From more than 20,000 genotypes initially evaluated only 114 reached the last stage. The objective was to assess how the data at SRT could be used to predict the probabilities of genotypes reaching the UYT. Phenotypic data from each genotype at SRT was integrated into the selection index (SIN) used by the cassava breeding program. Average SIN from all the progenies derived from each progenitor was then obtained. Average SIN is an approximation of the breeding value of each progenitor. Data clearly suggested that some genotypes were better progenitors than others (e.g., high number of their progenies reaching the UYT), suggesting important variation in breeding values of progenitors. However, regression of average SIN of each parental genotype on the number of their respective progenies reaching UYT resulted in a negligible coefficient of determination (r2 = 0.05). Breeding value (e.g., average SIN) at SRT was not efficient predicting which genotypes were more likely to reach the UYT stage. Number of families and progenies derived from a given progenitor were more efficient predicting the probabilities of the progeny from a given parent reaching the UYT stage. Large within-family genetic variation tends to mask the true breeding value of each progenitor. The use of partially inbred progenitors (e.g., S1 or S2 genotypes) would reduce the within-family genetic variation thus making the assessment of breeding value more accurate. Moreover, partial inbreeding of progenitors can improve the breeding value of the original (S0) parental material and sharply accelerate genetic gains. For instance, homozygous S1 genotypes for the dominant resistance to cassava mosaic disease (CMD) could be generated and selected. All gametes from these selected S1 genotypes would carry the desirable allele and

  11. Cassava Breeding I: The Value of Breeding Value.

    PubMed

    Ceballos, Hernán; Pérez, Juan C; Joaqui Barandica, Orlando; Lenis, Jorge I; Morante, Nelson; Calle, Fernando; Pino, Lizbeth; Hershey, Clair H

    2016-01-01

    Breeding cassava relies on several selection stages (single row trial-SRT; preliminary; advanced; and uniform yield trials-UYT). This study uses data from 14 years of evaluations. From more than 20,000 genotypes initially evaluated only 114 reached the last stage. The objective was to assess how the data at SRT could be used to predict the probabilities of genotypes reaching the UYT. Phenotypic data from each genotype at SRT was integrated into the selection index (SIN) used by the cassava breeding program. Average SIN from all the progenies derived from each progenitor was then obtained. Average SIN is an approximation of the breeding value of each progenitor. Data clearly suggested that some genotypes were better progenitors than others (e.g., high number of their progenies reaching the UYT), suggesting important variation in breeding values of progenitors. However, regression of average SIN of each parental genotype on the number of their respective progenies reaching UYT resulted in a negligible coefficient of determination (r (2) = 0.05). Breeding value (e.g., average SIN) at SRT was not efficient predicting which genotypes were more likely to reach the UYT stage. Number of families and progenies derived from a given progenitor were more efficient predicting the probabilities of the progeny from a given parent reaching the UYT stage. Large within-family genetic variation tends to mask the true breeding value of each progenitor. The use of partially inbred progenitors (e.g., S1 or S2 genotypes) would reduce the within-family genetic variation thus making the assessment of breeding value more accurate. Moreover, partial inbreeding of progenitors can improve the breeding value of the original (S0) parental material and sharply accelerate genetic gains. For instance, homozygous S1 genotypes for the dominant resistance to cassava mosaic disease (CMD) could be generated and selected. All gametes from these selected S1 genotypes would carry the desirable allele and

  12. Electrophiles and acute toxicity to fish

    SciTech Connect

    Hermens, J.L. )

    1990-07-01

    Effect concentrations in fish LC50 tests with directly acting electrophiles are lower than those of unreactive chemicals that act by narcosis. LC50 values of more hydrophobic reactive chemicals tend to approach those of unreactive chemicals. Quantitative studies to correlate fish LC50 data to physical-chemical properties indicate that LC50 values of reactive chemicals depend on hydrophobicity as well as chemical reactivity. In this paper, several examples will be given of chemical structures that are known as direct electrophiles. This classification might be useful to identify chemicals that are more effective at lower concentrations than unreactive compounds. Chemicals that require bioactivation are not included because almost no information is available on the influence of bioactivation on acute toxic effects in aquatic organisms.32 references.

  13. Graduates: Perceptions of MBA Value

    ERIC Educational Resources Information Center

    Bledsoe, Maynard T.; Oatsvall, Rebecca

    2009-01-01

    MBA worth--who decides? Much of the current assessment comes from market driven and/or institutional perspectives. This research examines responses from Meredith College MBA graduates to determine their perceptions of the worth and value of their MBA experience.

  14. Teaching the Values of Competition

    ERIC Educational Resources Information Center

    Buyer, Paul

    2005-01-01

    The author of this paper first learned about the values of competition as a member of the 1989 Star of Indiana Drum and Bugle Corps. Because they played more than thirty shows that summer, it was common to compete two nights in a row. He vividly remembers one such occasion. Their first show was outstanding, and they finished second. Everyone was…

  15. The Value of the Arts

    ERIC Educational Resources Information Center

    Tubbs, Nigel

    2013-01-01

    The value of the arts is often measured in terms of human creativity against instrumental rationality, while art for art's sake defends against a utility of art. Such critiques of the technical and formulaic are themselves formulaic, repeating the dualism of the head and the heart. How should we account for this formula? We should do so by…

  16. WORK VALUES OF THE HANDICAPPED.

    ERIC Educational Resources Information Center

    KINNANE, JOHN F.; SUZIEDELIS, ANTANAS

    TO DETERMINE THE WORK VALUES OF THE PHYSICALLY HANDICAPPED, A WORK MOTIVATION SCHEDULE WAS DEVELOPED AND ADMINISTERED TO 200 NORMAL WHITE MEN AND 200 WOMEN OF REPRESENTATIVE NATIONAL AVERAGE AGE AND EDUCATION AND TO CEREBRAL PALSIED, DEAF, 63 RECENT AMPUTEES FROM THE VIETNAM WAR AND NEURO-PSYCHIATRIC PATIENTS. COMPARISON OF THE TWO GROUPS SHOWED…

  17. Sexual Values of 783 Undergraduates

    ERIC Educational Resources Information Center

    Richey, Emily; Knox, David; Zusman, Marty

    2009-01-01

    The sexual values of absolutism (abstinence until marriage), relativism (sexual decisions made in reference to the nature of the relationship), and hedonism ("if it feels good, do it") were assessed in a convenience sample of 783 undergraduate students at a large southeastern university. Results revealed that relativism (62.1%) was the predominate…

  18. Children's Judgments of Expected Value.

    ERIC Educational Resources Information Center

    Schlottmann, Anne; Anderson, Norman H.

    1994-01-01

    Expected value judgments of 5- through 10-year-olds were studied by having children view roulette-type games and make judgments of how happy a puppet playing the game would be. Even the youngest children showed some understanding of probability dependence, with children under eight using an additive integration rule and children eight and older…

  19. What Works in Values Education

    ERIC Educational Resources Information Center

    Berkowitz, Marvin W.

    2011-01-01

    Values education (alternatively, moral education, character education) is the attempt, within schools, to craft pedagogies and supportive structures to foster the development of positive, ethical, pro-social inclinations and competencies in youth, including around strengthening their academic focus and achievement. Recent research has uncovered…

  20. Unshackled by Visions and Values.

    ERIC Educational Resources Information Center

    Brokenleg, Martin

    1996-01-01

    Uses a case study to demonstrate the effects of cultural conflict, alienation, anomie, and contemporary urban society on the lives of troubled Native American youth. Shows that by teaching traditional Native American values, such as visions of hope and independence, society can help these youth enjoy a promising future. (RJM)

  1. Value-sensitive psychiatric rehabilitation.

    PubMed

    Greenberg, David; Kalian, Moshe; Witztum, Eliezer

    2010-09-01

    Psychiatric rehabilitation contains value-laden concepts that may be unacceptable to certain cultures and many individuals. The concepts of independence and work are examined in a clash between mental health professionals in charge of national policies in psychiatric rehabilitation in Israel and a rehabilitation center for the severely mentally ill within the ultra-orthodox Jewish community. The government professionals considered that having the living quarters and work site in the same building deemed it unsuitable for rehabilitation, and too few progressed to independent living and working. As such, they ordered the center to be closed. Clients' families turned to the Supreme Court and the claims and counter claims reveal value-laden positions. The bases for misunderstanding and lack of cooperation between the government professionals and the rehabilitation center are explained in the context of everyday life and values in the ultra-orthodox Jewish community and attitudes in the general population. Fruitful cooperation is based on appreciating core values, identifying and working with the community's figures of authority, and accepting that the role of the mental health professional is to advise the community, within which the professional has no status.

  2. A Blizzard of a Value

    ERIC Educational Resources Information Center

    Bostic, Jonathan D.

    2015-01-01

    "Who has been to Dairy Queen® and purchased a Blizzard?®" Ms. Bosetti asked her students. During the summer, Bosetti had seen many of her former and future students at the local Dairy Queen enjoying Blizzard desserts and wondered, "Which Blizzard size is the best value?" She used this context for a ratios and proportions task…

  3. Values in Persons With Schizophrenia

    PubMed Central

    Stanghellini, Giovanni; Ballerini, Massimo

    2007-01-01

    This is an explorative study on the values of persons with schizophrenia based on transcripts of individual therapy sessions conducted for 40 persons with chart diagnoses of schizophrenia or schizotypal disorder. Values are action-guiding attitudes that subject human activities to be worthy of praise or blame. The schizophrenic value system conveys an overall crisis of common sense. The outcome of this has been designated as antagonomia and idionomia. Antagonomia reflects the choice to take an eccentric stand in the face of commonly shared assumptions and the here and now “other.” Idionomia reflects the feeling of the radical uniqueness and exceptionality of one's being with respect to common sense and the other human beings. This sentiment of radical exceptionality is felt as a “gift,” often in view of an eschatological mission or a vocation to a superior, novel, metaphysical understanding of the world. The aim of this study is neither establishing new diagnostic criteria nor suggesting that values play an etio-pathogenetical role in the development of schizophrenia but improving our understanding of the “meaning” of schizophrenic experiences and beliefs, and by doing so reducing stigmatization, and enhancing the specificity and validity of “psychotic symptoms” (especially bizarre delusions) and of “social and occupational dysfunction” through a detailed description of the anthropological and existential matrix they arise from. PMID:16940339

  4. Moral Rudders and Superintendent Values

    ERIC Educational Resources Information Center

    Kidder, Rushworth M.

    2008-01-01

    The core challenge is this--a difficult ethical decision, where values are in play and both sides have powerful moral arguments in their favor. One case presented in this article outlines a dilemma faced by one teacher who became a superintendent herself. The case exploded dramatically in a midsize metropolitan school district, where a principal…

  5. Added Value in Electronic Publications.

    ERIC Educational Resources Information Center

    Bothma, Theo J. D.

    Electronic publications are flooding the market. Some of these publications are created specifically for the electronic environment, but many are conversions of existing material to electronic format. It is not worth the time and effort merely to publish existing material in electronic format if no value is added in the conversion process. The…

  6. Richard Peters and Valuing Authenticity

    ERIC Educational Resources Information Center

    Degenhardt, M. A. B.

    2009-01-01

    Richard Peters has been praised for the authenticity of his philosophy, and inquiry into aspects of the development of his philosophy reveals a profound authenticity. Yet authenticity is something he seems not to favour. The apparent paradox is resolved by observing historical changes in the understanding of authenticity as an important value.…

  7. Education's Lasting Influence on Values.

    ERIC Educational Resources Information Center

    Hyman, Herbert H.; Wright, Charles R.

    This book examines the long-term effects of education on the values of adult Americans. To measure education's lasting effects the authors did a "secondary analysis" of national attitude surveys that had been conducted in four time periods from 1950 to 1975. Thirty-eight surveys that included 45,000 white adults from 25 to 72 years of age were…

  8. The value of percutaneous cholangiography

    PubMed Central

    Evison, Gordon; McNulty, Myles; Thomson, Colin

    1973-01-01

    Percutaneous cholangiograms performed on fifty patients in a district general hospital have been reviewed, and the advantages and limitations of the examination are described. The investigation is considered to have sufficient diagnostic value to warrant its inclusion in the diagnostic armamentarium of every general radiological department. ImagesFig. 1Fig. 2Fig. 3Fig. 4 PMID:4788917

  9. Forecasting the Value of Training

    ERIC Educational Resources Information Center

    Basarab, Dave

    2011-01-01

    The Predictive Evaluation (PE) model is a training and evaluation approach with the element of prediction. PE allows trainers and business leaders to predict the results, value, intention, adoption, and impact of training, allowing them to make smarter, more strategic training and evaluation investments. PE is invaluable for companies that…

  10. Valuing the Environment, K-6.

    ERIC Educational Resources Information Center

    Charlotte-Mecklenburg Public Schools, Charlotte, NC.

    This guide was developed for use in grades K-6 as an enrichment program based on clarifying values. The program, designed by teachers, aims to develop in the student a greater awareness and understanding of the community, themselves, and the earth. The program includes a number of environmental encounters. Topical themes lead teachers and students…

  11. Economic demand and essential value.

    PubMed

    Hursh, Steven R; Silberberg, Alan

    2008-01-01

    The strength of a rat's eating reflex correlates with hunger level when strength is measured by the response frequency that precedes eating (B. F. Skinner, 1932a, 1932b). On the basis of this finding, Skinner argued response frequency could index reflex strength. Subsequent work documented difficulties with this notion because responding was affected not only by the strengthening properties of the reinforcer but also by the rate-shaping effects of the schedule. This article obviates this problem by measuring strength via methods from behavioral economics. This approach uses demand curves to map how reinforcer consumption changes with changes in the "price" different ratio schedules impose. An exponential equation is used to model these demand curves. The value of this exponential's rate constant is used to scale the strength or essential value of a reinforcer, independent of the scalar dimensions of the reinforcer. Essential value determines the consumption level to be expected at particular prices and the response level that will occur to support that consumption. This approach permits comparing reinforcers that differ in kind, contributing toward the goal of scaling reinforcer value.

  12. More Value to Defining Quality

    ERIC Educational Resources Information Center

    Van Kemenade, Everard; Pupius, Mike; Hardjono, Teun W.

    2008-01-01

    There are lots of definitions of quality, and also of quality in education. Garvin (1984) discerns five approaches: the transcendental approach, the product-oriented approach, the customer-oriented approach, the manufacturing-oriented approach and the value-for-money approach. Harvey and Green (1993) give five interrelated concepts of quality as:…

  13. Baseball and American Cultural Values.

    ERIC Educational Resources Information Center

    Briley, Ronald

    1992-01-01

    Presents a lesson plan exploring social values and historical periods as it is reflected in the sport of baseball. Suggests that teachers start with an overview of the game's history and rules in the nineteenth century. Includes four sets of quotes relating to baseball and race, capitalism, community, and cultural context. (DK)

  14. The Epistemic Value of Diversity

    ERIC Educational Resources Information Center

    Robertson, Emily

    2013-01-01

    This article briefly considers current positions about whether the inclusion of the perspectives and interests of marginalised groups in the construction of knowledge is of epistemic value. It is then argued that applied social epistemology is the proper epistemic stance to take in evaluating this question. Theorists who have held that diversity…

  15. Rural-Urban Value Patterns.

    ERIC Educational Resources Information Center

    Christenson, James A.; Dillman, Don A.

    The purpose of this study was to assess whether ecological or occupational rural-urban differences imply sociocultural differences as measured by public values. Data were gathered during 1970 in a random state-wide survey of Washington residents, N = 3101, response rate = 75%. Two indicators were selected to measure the ecological aspect of…

  16. THE NUTRITIVE VALUE OF FUSARIA.

    PubMed

    Vinson, L J; Cerecedo, L R; Mull, R P; Nord, F F

    1945-04-13

    It has been shown that Fusarium lini B. grown on an artificial stock culture medium when supplemented with thiamin provides adequate amounts of the B-complex vitamins for normal growth, reproduction and lactation in mice, and that it compares very favorably with brewer's yeast in its food value.

  17. Estimation of environment-related properties of chemicals for design of sustainable processes: development of group-contribution+ (GC+) property models and uncertainty analysis.

    PubMed

    Hukkerikar, Amol Shivajirao; Kalakul, Sawitree; Sarup, Bent; Young, Douglas M; Sin, Gürkan; Gani, Rafiqul

    2012-11-26

    The aim of this work is to develop group-contribution(+) (GC(+)) method (combined group-contribution (GC) method and atom connectivity index (CI) method) based property models to provide reliable estimations of environment-related properties of organic chemicals together with uncertainties of estimated property values. For this purpose, a systematic methodology for property modeling and uncertainty analysis is used. The methodology includes a parameter estimation step to determine parameters of property models and an uncertainty analysis step to establish statistical information about the quality of parameter estimation, such as the parameter covariance, the standard errors in predicted properties, and the confidence intervals. For parameter estimation, large data sets of experimentally measured property values of a wide range of chemicals (hydrocarbons, oxygenated chemicals, nitrogenated chemicals, poly functional chemicals, etc.) taken from the database of the US Environmental Protection Agency (EPA) and from the database of USEtox is used. For property modeling and uncertainty analysis, the Marrero and Gani GC method and atom connectivity index method have been considered. In total, 22 environment-related properties, which include the fathead minnow 96-h LC(50), Daphnia magna 48-h LC(50), oral rat LD(50), aqueous solubility, bioconcentration factor, permissible exposure limit (OSHA-TWA), photochemical oxidation potential, global warming potential, ozone depletion potential, acidification potential, emission to urban air (carcinogenic and noncarcinogenic), emission to continental rural air (carcinogenic and noncarcinogenic), emission to continental fresh water (carcinogenic and noncarcinogenic), emission to continental seawater (carcinogenic and noncarcinogenic), emission to continental natural soil (carcinogenic and noncarcinogenic), and emission to continental agricultural soil (carcinogenic and noncarcinogenic) have been modeled and analyzed. The application

  18. Estimation of environment-related properties of chemicals for design of sustainable processes: development of group-contribution+ (GC+) property models and uncertainty analysis.

    PubMed

    Hukkerikar, Amol Shivajirao; Kalakul, Sawitree; Sarup, Bent; Young, Douglas M; Sin, Gürkan; Gani, Rafiqul

    2012-11-26

    The aim of this work is to develop group-contribution(+) (GC(+)) method (combined group-contribution (GC) method and atom connectivity index (CI) method) based property models to provide reliable estimations of environment-related properties of organic chemicals together with uncertainties of estimated property values. For this purpose, a systematic methodology for property modeling and uncertainty analysis is used. The methodology includes a parameter estimation step to determine parameters of property models and an uncertainty analysis step to establish statistical information about the quality of parameter estimation, such as the parameter covariance, the standard errors in predicted properties, and the confidence intervals. For parameter estimation, large data sets of experimentally measured property values of a wide range of chemicals (hydrocarbons, oxygenated chemicals, nitrogenated chemicals, poly functional chemicals, etc.) taken from the database of the US Environmental Protection Agency (EPA) and from the database of USEtox is used. For property modeling and uncertainty analysis, the Marrero and Gani GC method and atom connectivity index method have been considered. In total, 22 environment-related properties, which include the fathead minnow 96-h LC(50), Daphnia magna 48-h LC(50), oral rat LD(50), aqueous solubility, bioconcentration factor, permissible exposure limit (OSHA-TWA), photochemical oxidation potential, global warming potential, ozone depletion potential, acidification potential, emission to urban air (carcinogenic and noncarcinogenic), emission to continental rural air (carcinogenic and noncarcinogenic), emission to continental fresh water (carcinogenic and noncarcinogenic), emission to continental seawater (carcinogenic and noncarcinogenic), emission to continental natural soil (carcinogenic and noncarcinogenic), and emission to continental agricultural soil (carcinogenic and noncarcinogenic) have been modeled and analyzed. The application

  19. Systems of Values and Their Multidimensional Representations

    ERIC Educational Resources Information Center

    Jones, Russell A.; And Others

    1978-01-01

    Values were elicited spontaneously from a sample of undergraduates and adults attending college, and were compared to Rokeach's terminal and instrumental values. Multidimensional scaling revealed a simpler structure among spontaneously mentioned values than Rokeach's values. (JKS)

  20. Interclonal variation in the acute and delayed toxicity of cadmium to the European prosobranch gastropod Potamopyrgus antipodarum (Gray).

    PubMed

    Jensen, A; Forbes, V E

    2001-02-01

    The lethal responses of three European clones--A, B, and C-of the prosobranch snail Potamopyrgus antipodarum to acute cadmium exposure were examined by the use of a conventional LC50 test and a delayed toxicity test. The questions addressed were: (1) Are there differences in susceptibility (LC50 values and uniformity of response) among the three European clones of P. antipodarum? (2) Are the patterns of differences in susceptibility among clones observed in the LC50 test also observed for the delayed toxicity test? (3) Is there concordance in the ranking of susceptibility among clones under acute cadmium exposure and under chronic cadmium exposure? The results showed that the widths of the tolerance distribution differed among clones. Clones A and B had a steeper slope than clone C (for clone A the difference was marginally significant), which indicates that individuals from clones A and B showed a more uniform response to acute lethal cadmium stress than individuals from clone C. On the basis of the measured differences in LC50 values, clone A individuals showed the highest tolerance to acute cadmium (LC50 value: 1.92 mg Cd L(-1)) followed by clone B (LC50 value: 1.29 mg Cd L(-1)) and clone C (LC50 value: 0.56 mg Cd L(-1)). Clone C was significantly less tolerant than clones A and B. The delayed toxicity test showed a similar pattern to the LC50 test with regard to tolerance differences among clones; however, mortality continued following transfer to clean water, indicating that cadmium was lethal at much lower concentrations than indicated by the conventional LC50 test. Results of the LC50 test and the delayed toxicity test in the present study were in general agreement with results from chronic cadmium exposure experiments (Jensen et al. [2000] Ecol Appl [submitted]), i.e., the least susceptible clone A in the acute cadmium exposure test was also the least susceptible clone in the chronic cadmium exposure test. Based on the dramatic differences between the LC50

  1. Comparison of on-site and laboratory toxicity tests: derivation of site-specific criteria for un-ionized ammonia in a Colorado transitional stream

    USGS Publications Warehouse

    Nimmo, Del Wayne R.; Link, Denise; Parrish, Loys P.; Rodriguez, Glenn J.; Wuerthele, William; Davies, Patrick H.

    1989-01-01

    Acute tests with fathead minnows (Pimephales prornelas Rafinesque), johnny darters (Etheostoma nigrum Rafinesque), white suckers (Catostomus commersoni Lacépède) and acute and chronic tests with Ceriodaphnia dubia were conducted to evaluate whether characteristics of the St. Vrain River in Colorado would ameliorate or enhance toxicity of un-ionized ammonia compared to laboratory (well) water and LC50 values found in the literature. Concurrently, tests were conducted on dilutions of Longmont, Colorado, wastewater to evaluate its toxicity in differing ammonia concentrations. Tests were conducted at two temperatures (approximately 6 and 20°C) to simulate seasonal differences. LC50s for fishes in the St. Vrain River water were similar to LC50s in laboratory water, indicating there was no site water effect. LC50s derived for fishes tested in warm conditions were within a factor of about two or three of literature values. However, the constituents in or characteristics of the wastewater appeared to enhance ammonia toxicity. Literature values (LC50s) for resident aquatic organisms and the new LC50 value for johnny darters tested on-site were used to derive site-specific criteria for un-ionized ammonia. Greater sensitivities of species to ammonia at cold versus warm temperatures suggests that colder, low-flow conditions may be a critical period for warm-water aquatic communities with regard to ammonia toxicity.

  2. Baseline Susceptibility of Lygus lineolaris (Hemiptera: Miridae) to Novaluron.

    PubMed

    Parys, Katherine A; Snodgrass, Gordon L; Luttrell, Randall G; Allen, K Clint; Little, Nathan S

    2016-02-01

    Tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), populations were collected from field locations in the Mississippi River Delta of Arkansas, Louisiana, and Mississippi. Third-instar F(1) nymphs from each field location, in addition to a laboratory colony, were screened for susceptibility to novaluron. Both a glass vial bioassay and a diet-incorporated bioassay used dose-response regression lines to calculate LC(50) and LC(90) values for novaluron. Mean LC(50s) for glass vial bioassays ranged from 44.70 ± 3.58 to 66.54 ± 4.19 μg/vial, while mean LC(50s) for diet-incorporated bioassays ranged from 12.10 ± 0.77 to 17.63 ± 2.42 μg/200 ml of artificial diet. A comparison of LC(50) values from the same field population screened using both bioassay methods failed to show a relationship. LC(50) values from field locations were compared with a historically susceptible population from Crossett, AR. Results indicated that considerable variability in susceptibility to novaluron exists within field populations of tarnished plant bugs across the Delta, including some locations with lower LC(50) values than a historically susceptible population. PMID:26546489

  3. Metal and pharmaceutical mixtures: is ion loss the mechanism underlying acute toxicity and widespread additive toxicity in zebrafish?

    PubMed

    Alsop, Derek; Wood, Chris M

    2013-09-15

    The acute toxicities and mechanisms of action of a variety of environmental contaminants were examined using zebrafish larvae (Danio rerio; 4-8 days post fertilization). Toxic interactions were observed between metals. For example, the addition of a sublethal level of nickel (15% of the LC50, one third of the LC01) to all copper treatments decreased the copper 96 h LC50 by 58%, while sublethal copper exposure (6% of the copper LC50, 13% of the LC01) decreased the cadmium 96 h LC50 by 47%. Two predictive models were assessed, the concentration addition (CA) model, which assumes similar mechanisms of action, and the independent action (IA) model, which assumes different mechanisms of action. Quantitative comparisons indicated the CA model performed better than the IA model; the latter tended to underestimate combined toxicity to a greater extent. The effects of mixtures with nickel or ammonia were typically additive, while mixtures with copper or cadmium were typically greater than additive. Larvae exposed to cadmium, copper or nickel experienced whole body ion loss. Decreases were greatest for Na(+) followed by K(+) (as high as 19% and 9%, respectively, in 24h). Additive toxicity between copper and other pharmaceutical compounds such as fluoxetine (Prozac™), β-naphthoflavone, estrogen and 17α-ethinylestradiol were also observed. Similar to metals, acutely toxic concentrations of fluoxetine, β-naphthoflavone and ammonia all decreased whole body Na(+) and K(+). Overall, whole body Na(+) loss showed the greatest correlation with mortality across a variety of toxicants. We theorize that a disruption of ion homeostasis may be a common mechanism underlying the acute additive toxicity of many contaminants in fish.

  4. Comparison of nanosilver and ionic silver toxicity in Daphnia magna and Pimephales promelas.

    PubMed

    Hoheisel, Sarah M; Diamond, Steve; Mount, David

    2012-11-01

    The increasing use of nanosilver in consumer products and the likelihood of environmental exposure warrant investigation into the toxicity of nanosilver to aquatic organisms. A series of studies were conducted comparing the potency of nanosilver to ionic silver (Ag(+)) at acute and sublethal levels using two test organisms (Daphnia magna and Pimephales promelas). The 48-h D. magna median lethal concentration (LC50) of multiple sizes (10, 20, 30, and 50 nm) of commercially prepared nanosilver (nanoComposix) ranged from 4.31 to 30.36 µg total Ag L(-1) with increasing toxicity associated with decreasing particle size. A strong relationship between estimated specific particle surface area and acute toxicity was observed. Nanosilver suspensions (10 nm) treated with cation exchange resin to reduce the concentration of Ag(+) associated with it were approximately equally toxic to D. magna compared to untreated nanosilver (48-h LC50s were 2.15 and 2.79 µg total Ag L(-1), respectively). The 96-h LC50 and 7-d sublethal 20% effective concentrations (EC20s) for P. promelas were 89.4 and 46.1 µg total Ag L(-1), respectively, for 10 nm nanosilver and 4.70 and 1.37 µg total Ag L(-1), respectively, for Ag(+); the resulting ratios of 96-h LC50 to 7-d EC20 were not significantly different for nanosilver and ionic silver. Overall, these studies did not provide strong evidence that nanosilver either acts by a different mechanism of toxicity than ionic silver, or is likely to cause acute or lethal toxicity beyond that which would be predicted by mass concentration of total silver. This in turn suggests that regulatory approaches based on the toxicity of ionic silver to aquatic life would not be underprotective for environmental releases of nanosilver.

  5. Toxicity of Chlorophyllin against Lymnaea acuminata at Different Wavelengths of Visible Light.

    PubMed

    Chaturvedi, Divya; Singh, Vinay Kumar

    2016-08-01

    Fasciolosis is a water and food-borne disease caused by the liver fluke Fasciola hepatica and Fasciola gigantica. This disease is widespread in different parts of the world. Lymnaeidae and Planorbidae snails are the intermediate hosts of these flukes. Snail population management is a good tool to control fasciolosis because gastropods represent the weakest link in the life-cycle of trematodes. Chlorophyll can be extracted from any green plant. Chlorophyllin was prepared from spinach in 100% ethanol by using different types of chemicals. The chlorophyll obtained from spinach was transformed into water-soluble chlorophyllin. In the present paper, toxicity of chlorophyllin against the snail Lymnaea acuminata was time and concentration dependent. The toxicity of extracted and pure chlorophyllin at continuous 4 h exposure of sunlight was highest with lethal concentration (LC50) of 331.01 mg/L and 2.60 mg/L, respectively, than discontinuous exposure of sunlight up to 8 h with LC50 of 357.04 mg/L and 4.94 mg/L, respectively. Toxicity of extracted chlorophyllin was noted in the presence of different monochromatic visible lights. The highest toxicity was noted in yellow light (96 h, LC50 392.77 mg/L) and the lowest in green light (96 h, LC50 833.02 mg/L). Chlorophyllin in combination with solar radiation or different wavelength of monochromatic visible lights may become a latent remedy against the snail L. acuminata. It was demonstrated that chlorophyllin was more toxic in sunlight. Chlorophyllin is ecologically safe and more economical than synthetic molluscicides which have the potential to control the incidence of fasciolosis in developing countries. PMID:27688849

  6. Toxicity of Chlorophyllin against Lymnaea acuminata at Different Wavelengths of Visible Light.

    PubMed

    Chaturvedi, Divya; Singh, Vinay Kumar

    2016-08-01

    Fasciolosis is a water and food-borne disease caused by the liver fluke Fasciola hepatica and Fasciola gigantica. This disease is widespread in different parts of the world. Lymnaeidae and Planorbidae snails are the intermediate hosts of these flukes. Snail population management is a good tool to control fasciolosis because gastropods represent the weakest link in the life-cycle of trematodes. Chlorophyll can be extracted from any green plant. Chlorophyllin was prepared from spinach in 100% ethanol by using different types of chemicals. The chlorophyll obtained from spinach was transformed into water-soluble chlorophyllin. In the present paper, toxicity of chlorophyllin against the snail Lymnaea acuminata was time and concentration dependent. The toxicity of extracted and pure chlorophyllin at continuous 4 h exposure of sunlight was highest with lethal concentration (LC50) of 331.01 mg/L and 2.60 mg/L, respectively, than discontinuous exposure of sunlight up to 8 h with LC50 of 357.04 mg/L and 4.94 mg/L, respectively. Toxicity of extracted chlorophyllin was noted in the presence of different monochromatic visible lights. The highest toxicity was noted in yellow light (96 h, LC50 392.77 mg/L) and the lowest in green light (96 h, LC50 833.02 mg/L). Chlorophyllin in combination with solar radiation or different wavelength of monochromatic visible lights may become a latent remedy against the snail L. acuminata. It was demonstrated that chlorophyllin was more toxic in sunlight. Chlorophyllin is ecologically safe and more economical than synthetic molluscicides which have the potential to control the incidence of fasciolosis in developing countries.

  7. Toxicity of Chlorophyllin against Lymnaea acuminata at Different Wavelengths of Visible Light

    PubMed Central

    Chaturvedi, Divya; Singh, Vinay Kumar

    2016-01-01

    Fasciolosis is a water and food-borne disease caused by the liver fluke Fasciola hepatica and Fasciola gigantica. This disease is widespread in different parts of the world. Lymnaeidae and Planorbidae snails are the intermediate hosts of these flukes. Snail population management is a good tool to control fasciolosis because gastropods represent the weakest link in the life-cycle of trematodes. Chlorophyll can be extracted from any green plant. Chlorophyllin was prepared from spinach in 100% ethanol by using different types of chemicals. The chlorophyll obtained from spinach was transformed into water-soluble chlorophyllin. In the present paper, toxicity of chlorophyllin against the snail Lymnaea acuminata was time and concentration dependent. The toxicity of extracted and pure chlorophyllin at continuous 4 h exposure of sunlight was highest with lethal concentration (LC50) of 331.01 mg/L and 2.60 mg/L, respectively, than discontinuous exposure of sunlight up to 8 h with LC50 of 357.04 mg/L and 4.94 mg/L, respectively. Toxicity of extracted chlorophyllin was noted in the presence of different monochromatic visible lights. The highest toxicity was noted in yellow light (96 h, LC50 392.77 mg/L) and the lowest in green light (96 h, LC50 833.02 mg/L). Chlorophyllin in combination with solar radiation or different wavelength of monochromatic visible lights may become a latent remedy against the snail L. acuminata. It was demonstrated that chlorophyllin was more toxic in sunlight. Chlorophyllin is ecologically safe and more economical than synthetic molluscicides which have the potential to control the incidence of fasciolosis in developing countries. PMID:27688849

  8. Toxicity of Chlorophyllin against Lymnaea acuminata at Different Wavelengths of Visible Light

    PubMed Central

    Chaturvedi, Divya; Singh, Vinay Kumar

    2016-01-01

    Fasciolosis is a water and food-borne disease caused by the liver fluke Fasciola hepatica and Fasciola gigantica. This disease is widespread in different parts of the world. Lymnaeidae and Planorbidae snails are the intermediate hosts of these flukes. Snail population management is a good tool to control fasciolosis because gastropods represent the weakest link in the life-cycle of trematodes. Chlorophyll can be extracted from any green plant. Chlorophyllin was prepared from spinach in 100% ethanol by using different types of chemicals. The chlorophyll obtained from spinach was transformed into water-soluble chlorophyllin. In the present paper, toxicity of chlorophyllin against the snail Lymnaea acuminata was time and concentration dependent. The toxicity of extracted and pure chlorophyllin at continuous 4 h exposure of sunlight was highest with lethal concentration (LC50) of 331.01 mg/L and 2.60 mg/L, respectively, than discontinuous exposure of sunlight up to 8 h with LC50 of 357.04 mg/L and 4.94 mg/L, respectively. Toxicity of extracted chlorophyllin was noted in the presence of different monochromatic visible lights. The highest toxicity was noted in yellow light (96 h, LC50 392.77 mg/L) and the lowest in green light (96 h, LC50 833.02 mg/L). Chlorophyllin in combination with solar radiation or different wavelength of monochromatic visible lights may become a latent remedy against the snail L. acuminata. It was demonstrated that chlorophyllin was more toxic in sunlight. Chlorophyllin is ecologically safe and more economical than synthetic molluscicides which have the potential to control the incidence of fasciolosis in developing countries.

  9. Living the Good (Work) Life: Implications of General Values for Work Values

    ERIC Educational Resources Information Center

    Carlstrom, Aaron H.

    2011-01-01

    Advances in the understanding of general values from personality and social psychology apply to work values. In this paper, I introduce the concepts of values, value priorities, motivational goals, value types, and personal value systems used to clarify work values. I also introduce the terms basic and broad value and work value types. Second, I…

  10. Process for recovering actinide values

    DOEpatents

    Horwitz, E. Philip; Mason, George W.

    1980-01-01

    A process for rendering actinide values recoverable from sodium carbonate scrub waste solutions containing these and other values along with organic compounds resulting from the radiolytic and hydrolytic degradation of neutral organophosphorous extractants such as tri-n butyl phosphate (TBP) and dihexyl-N,N-diethyl carbamylmethylene phosphonate (DHDECAMP) which have been used in the reprocessing of irradiated nuclear reactor fuels. The scrub waste solution is preferably made acidic with mineral acid, to form a feed solution which is then contacted with a water-immiscible, highly polar organic extractant which selectively extracts the degradation products from the feed solution. The feed solution can then be processed to recover the actinides for storage or recycled back into the high-level waste process stream. The extractant is recycled after stripping the degradation products with a neutral sodium carbonate solution.

  11. Neuronal imprinting of human values.

    PubMed

    Delgado, J M

    2000-03-01

    In the 21st century, psychophysiology will face the challenge of establishing ethical principles and practical means for the genetic and social influencing of the development of human beings. Neuronal imprinting of beliefs and morality within infantile minds will be necessary for the peaceful coexistence of races and cultures. This process requires study and consideration, among others, of the following psychophysiological facts: (1) Genes do not transmit moral values. (2) Material support of physiological activities is necessary for the existence and development of mental functions. (3) Imprinting of human values is based on material changes within neuronal structures. (4) Early neuronal imprinting is performed without personal awareness or consent of the individual and depends on sensory inputs, mainly from the social structure of the group. (5) Biological structures lack values. Personal and social antagonisms do not depend on genes, but on cultural indoctrination. (6) Pleasure and punishment (positive and negative reinforcement) are the two main elements, which regulate animal and human behavior. (7) Values must be chosen by adults, who decide the questions 'why'? 'when'? 'which ones'?, 'who should teach'?, 'what?' and 'how'? (8) Many biological imperatives are shared by all animals and by all people. Human beings may be considered the 'crickets of the Universe', unable to understand the mysteries of nature because of our insufficient neuronal capacity. (9) Our emotional life is mainly related to the structure of the limbic system controlled by the neocortex. (10) New theories based on the integration of physics, chemistry, biology and other specific areas of knowledge, as proposed by the General Theory of Systems, will avoid 'opposites', favoring the acceptance of complementary aspects of reality. (11) Early education will promote preferential learning which depends on both genetic endowment and neuronal development influenced by experience. It is the

  12. Enduring values of municipal utilities

    SciTech Connect

    Telly, C.S.; Grove, J.F.

    1981-05-01

    The value of municipal utilities is assessed in terms of their social responsibility, the political responsiveness of the owners, and pricing policy - issues which conflict with the traditional concept of corporate responsibility to the shareholder and which reveal a growing demand for accountability. Although municipal utilities are only a small part of the economic, legal, and political setting, they contribute as a small, locally-controlled natural monopoly to the American goals of democracy and self-determination. (DCK)

  13. Maximising value from PFI contracts.

    PubMed

    Prosser, Karen; Gates, Russell

    2012-05-01

    Against a backdrop where the Coalition Government has said more 'value' needs to be squeezed out of existing healthcare PFI projects, Karen Prosser, head of the health sector team at built asset consultancy, EC Harris, and Russell Gates, one of the company's partners on the same team, set out some of the key elements that NHS Trusts with operational PFI contracts should consider when undertaking a contract savings review.

  14. P value interpretations and considerations

    PubMed Central

    Ronna, Brenden; Ott, Ulrike

    2016-01-01

    Application and interpretation of statistical evaluation of relationships is a necessary element in biomedical research. Statistical analyses rely on P value to demonstrate relationships. The traditional level of significance, P<0.05, can be negatively impacted by small sample size, bias, and random error, and has evolved to include interpretation of statistical trends, correction factors for multiple analyses, and acceptance of statistical significance for P>0.05 for complex relationships such as effect modification. PMID:27747028

  15. Valuing ecosystem integrity and health

    SciTech Connect

    Rolston, H. III

    1995-12-31

    There is widespread concern for valuing ecosystem integrity and health, in Congressional legislation, in policy for ecosystem management, sustainable development, and environmental quality. Both integrity and health are combined fact-value words that significantly mix science and advocacy. Science orients policy, though policy also orients science. Recent ecological science raises questions about the mix of stability and historical change in ecosystems, about how structure and process combine to form biotic communities, about order and disorder in natural systems, and the scales on which these occur. Concern for sustainable development mixes the concern for a sustainable biosphere. Ecosystem integrity and health require much restoration of degraded environments, but restoration goals also mix science and values. A traditional attitude toward nature as resources to be for several centuries, is being challenged by an attitude toward nature as resources to be managed by sound scientific management, increasingly successful for several centuries, is being challenged by an attitude of responsibility for harmonizing culture with nature. This will require an unprecendented mix of science, ethics, and policy in the century ahead. It would be a tragic failure of human culture, especially of modern scientifically advanced culture, if it were further to degrade the integrity, health, and biodiversity achieved over many millennia, leaving a still more depauperate Earth. Homo sapiens, improverishing people and the planet, would not be the {open_quotes}wise{close_quotes} species at all.

  16. Historical Medical Value of Donguibogam

    PubMed Central

    Song, Bong-Keun; Won, Jin-Hee

    2016-01-01

    Oriental medicine, since its origin in China, has had a long history extending over 2000 years. Today, it comprises several types of medicine predominately practiced in East Asia, including traditional Chinese, traditional Korean, and Kampo medicine. The distinctive medical system of traditional Korean medicine was established shortly after the publication of Donguibogam by Dr. Heo Jun in 1613. Donguibogam is highly acclaimed across East Asia; in 2009, in light of its historical medical value, the United Nations Educational, Scientific, and Cultural Organization registered the book on its cultural heritage list. Here, we review the historical medical value of Donguibogam. The findings confirm that Donguibogam developed a unique and independent form of traditional Korean medicine and innovatively reformed the disease classification system. Moreover, Donguibogam emphasized the importance of disease prevention and medical pragmatism. This book also accelerated the development of folk medicine. Owing to its historical medical value, Donguibogam is now considered the 'bible' of Oriental medicine. Its wide acceptance has contributed to the expansion of Korean medicine utilization among the general public. Donguibogam has also played an important role in the establishment of traditional Korean medicine as a universally valid and original form of medicine, independent of traditional Chinese medicine. PMID:27280045

  17. Historical Medical Value of Donguibogam.

    PubMed

    Song, Bong-Keun; Won, Jin-Hee; Kim, Sungchul

    2016-03-01

    Oriental medicine, since its origin in China, has had a long history extending over 2000 years. Today, it comprises several types of medicine predominately practiced in East Asia, including traditional Chinese, traditional Korean, and Kampo medicine. The distinctive medical system of traditional Korean medicine was established shortly after the publication of Donguibogam by Dr. Heo Jun in 1613. Donguibogam is highly acclaimed across East Asia; in 2009, in light of its historical medical value, the United Nations Educational, Scientific, and Cultural Organization registered the book on its cultural heritage list. Here, we review the historical medical value of Donguibogam. The findings confirm that Donguibogam developed a unique and independent form of traditional Korean medicine and innovatively reformed the disease classification system. Moreover, Donguibogam emphasized the importance of disease prevention and medical pragmatism. This book also accelerated the development of folk medicine. Owing to its historical medical value, Donguibogam is now considered the 'bible' of Oriental medicine. Its wide acceptance has contributed to the expansion of Korean medicine utilization among the general public. Donguibogam has also played an important role in the establishment of traditional Korean medicine as a universally valid and original form of medicine, independent of traditional Chinese medicine. PMID:27280045

  18. Harmonization of nutrient intake values.

    PubMed

    King, Janet C; Garza, Cutberto

    2007-03-01

    The conceptual framework for the various NIVs is depicted in figure 1 along with the methodological approaches and applications. The NIVs consist of two values derived from a statistical evaluation of data on nutrient requirements, the average nutrient requirement (ANR), or nutrient toxicities, the upper nutrient level (UNL). The individual nutrient levelx (INLx) is derived from the distribution of average nutrient requirements. The percentile chosen is often 98%, which is equivalent to 2 SD above the mean requirement. Concepts underlying the NIVs include criteria for establishing a nutrient requirement, e.g., ferritin stores, nitrogen balance, or serum vitamin C. Once the requirement for the absorbed nutrient is determined, it may be necessary to adjust the value for food sources, i.e., bioavailability, or host factors, such as the effect of infection on nutrient utilization. Other concepts that committees may want to consider when establishing NIVs include the effects of genetic variation on nutrient requirements and the role of the nutrient in preventing long-term disease. Two fundamental uses of NIVs are for assessing the adequacy of nutrient intakes and for planning diets for individuals and populations. Establishing the NIV using the statistical framework proposed in this report improves the efficacy of the values for identifying risks of nutrient deficiency or excess among individuals and populations. NIVs also are applied to a number of aspects of food and nutrition policy. Some examples include regulatory issues and trade, labeling, planning programs for alleviating public health nutrition problems, food fortification, and dietary guidance.

  19. ADSORPTION METHOD FOR SEPARATING THORIUM VALUES FROM URANIUM VALUES

    DOEpatents

    Boyd, G.E.; Russell, E.R.; Schubert, J.

    1959-08-01

    An improved ion exchange method is described for recovery of uranium and thorium values as separate functions from an aqueous acidic solution containing less than 10/sup -3/ M thorium ions and between 0.1 and 1 M uranyl ions. The solution is passed through a bed of cation exchange resin in the acid form to adsorb all the thorium ions and a portion of the uranyl ions. The uranium is eluted by means of aqueous 0.1 to 0.4 M sulfuric acid. The thorium may then be stripped from the resin by elution with aqueous 0.5 M oxalic acid.

  20. Making equity a value in value-based health care.

    PubMed

    Alberti, Philip M; Bonham, Ann C; Kirch, Darrell G

    2013-11-01

    Equity in health and health care in America continues to be a goal unmet. Certain demographic groups in the United States-including racial and ethnic minorities and individuals with lower socioeconomic status-have poorer health outcomes across a wide array of diseases, and have higher all-cause mortality. Yet despite growing understanding of how social-, structural-, and individual-level factors maintain and create inequities, solutions to reduce or eliminate them have been elusive. In this article, the authors envision how disparities-related provisions in the Affordable Care Act and other recent legislation could be linked with new value-based health care requirements and payment models to create incentives for narrowing health care disparities and move the nation toward equity.Specifically, the authors explore how recent legislative actions regarding payment reform, health information technology, community health needs assessments, and expanding health equity research could be woven together to build an evidence base for solutions to health care inequities. Although policy interventions at the clinical and payer levels alone will not eliminate disparities, given the significant role the social determinants of health play in the etiology and maintenance of inequity, such policies can allow the health care system to better identify and leverage community assets; provide high-quality, more equitable care; and demonstrate that equity is a value in health. PMID:24072123

  1. Variability in the relationships for alfalfa stem 16- and 96-h in vitro neutral detergent fiber digestibility with composition due to maturity and harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignin concentration is strongly negatively correlated with in vitro digestibility of neutral detergent fiber (IVNDFD) when examined across a wide forage maturity range, but this relationship is less clear among forages of similar maturity. We examined the relationships of IVNDFD with lignin and oth...

  2. Effects of chlorpyrifos on the transcription of CYP3A cDNA, activity of acetylcholinesterase, and oxidative stress response of goldfish (Carassius auratus).

    PubMed

    Ma, Junguo; Liu, Yang; Niu, Daichun; Li, Xiaoyu

    2015-04-01

    Chlorpyrifos (CPF) is the widely used organophosphate pesticide in agriculture throughout the world. It has been found that CPF is relatively safe to human but highly toxic to fish. In this study, acute toxicity of CPF on goldfish was determined and then the transcription of goldfish cytochrome P450 (CYP) 3A was evaluated after 96 h of CPF exposure at concentrations of 15.3 [1/10 50% lethal concentration (LC50 )] or 51 μg L(-1) (1/3 LC50 ) of CPF. Meanwhile, the enzymatic activities of acetylcholinesterase (AChE), superoxide dismutase (SOD), and catalase (CAT), total antioxidant activity (T-AOC), and the contents of malondialdehyde (MDA) in the liver or brain of goldfish were also determined. The results of acute toxicity testing showed that the 96-h LC50 of CPF to the goldfish was 153 μg L(-1) . Moreover, a length sequence of 1243 bp CYP3A cDNA encoding for 413 amino acids from goldfish liver was cloned. Polymerase chain reaction results reveal that CPF exposure downregulates CYP 3A transcription in goldfish liver, suggesting that goldfish CYP 3A may be not involved in CPF bioactivation. Finally, the results of biochemical assays indicate that 96 h of CPF exposure remarkably inhibits AChE activity in fish liver or brain, alters hepatic antioxidant enzyme activities, decreases brain T-AOC, and causes lipid peroxidation in fish liver. These results suggest that oxidative stress might be involved in CPF toxicity on goldfish.

  3. Cytotoxicity and antiviral activity of methanol extract from Polygonum minus

    NASA Astrophysics Data System (ADS)

    Wahab, Noor Zarina Abd; Bunawan, Hamidun; Ibrahim, Nazlina

    2015-09-01

    A study was carried out to test the cytotoxicity and antiviral effects of methanolic extracts from the leaves and stem of Polygonum minus or kesum. Cytotoxicity tests were performed on Vero cells indicates the LC50 value for leaf extract towards the Vero cells was 875 mg/L and the LC50 value for stem extract was 95 mg/L. The LC50 values indidcate the non-cytotoxic effect of the extracts and worth for further testing. Antiviral test were carried out towards herpes simplex virus infected Vero cells using three concentration of extract which were equivalent to 1.0 LC50, 0.1 LC50 and 0.01 LC50. Three different treatments to detect antiviral activity were used. Mild antiviral activity of the stem extract was detected when cells were treated for 24 hours with plant extract before viral infection. This demonstrates the capability of the test compound to protect the cells from viral attachment and of the possible prophylactic effect of the P. minus stem methanol extract.

  4. Comparative responses of speckled dace and cutthroat trout to air-supersaturated water

    SciTech Connect

    Nebeker, A.V.; Hauck, A.K.; Baker, F.D.; Weitz, S.L.

    1980-11-01

    Speckled dace (Rhinichthys osculus) are more tolerant of air-supersaturated water than adult or juvenile cutthroat trout (Salmo clarki). Speckled dace were tested in concentrations from 110 to 142% saturation and had a 96-hour median lethal concentration (LC50) of 140%, a 7-day LC50 of 137%, and 2-week LC50's of 129 and 131% saturation. The estimated mean threshold concentration, based on time to 50% death (TM50), was 123% saturation. The speckled dace also exhibited consistent external signs of gas bubble disease. Cutthroat trout were tested from 111 to 130% saturation and had 96-hour LC50's of 119 and 120% (adults) and 119 and 119% (juveniles) saturation. Estimated mean threshold concentrations (from TM50 values) were 117% (adults) and 114% (juveniles) saturation. Signs of gas bubble disease exhibited by the cutthroat trout were similar to those seen with other salmonids examined in earlier studies.

  5. Sensitivity of species to chemicals: dose-response characteristics for various test types (coldbloodedLC50, cold-blooded LR50 and warm-blooded LD50) and modes of action

    EPA Science Inventory

    While sensitivity of model species to common toxicants has been addressed, a systematic analysis of inter-species variability for different test types, modes of action and species is as yet lacking. Hence, the aim of the present study was to identify similarities and differences ...

  6. The Predictive Value of Foreshocks

    NASA Astrophysics Data System (ADS)

    Papadopoulos, G. A.; Avlonitis, M.; Di Fiore, B.; Minadakis, G.

    2012-04-01

    Foreshock activity was considered as a potential precursor of mainshocks since the 1960's. This is because foreshocks come directly from the source where mainshock is under preparation. However, the precise predictive value of foreshocks remained unrevealed due to the lack of precise earthquake catalogue data. We use recent examples of foreshocks from Japan, Italy, Greece and California and show that significant changes of seismicity in space-time-size domains during precisely located foreshock sequences provide seismicity patterns bearing high probability gain before the mainshock. The power-law increase of the event rate and the move of foreshocks towards mainshock epicenter indicate an accumulated or cascade stress redistribution process and a nucleation process, respectively. On the other hand, the statistically significant drop of b-value during foreshock sequences, from physical point of view provides clues for a softening material process in the seismogenic volume. We show analytically that the microstructural parameter α of the Olami-Feder-Christensen model controls the macroscopically observed b-value. This is further supported by our simulation results. The seismicity changes in the time, space and size domains during foreshocks provide information about the time and space of mainshock preparation as well as about the lower threshold of the mainshock magnitude, M. However, they do not provide an approximation of M. The recent examples used yield evidence that the foreshock area is likely a function of M. We propose that in selected target areas the close seismicity monitoring may provide evidence for foreshock activity beforehand, which may open possibilities for the predictability of mainshocks.

  7. Tolerance of ciliated protozoan Paramecium bursaria (Protozoa, Ciliophora) to ammonia and nitrites

    NASA Astrophysics Data System (ADS)

    Xu, Henglong; Song, Weibo; Lu, Lu; Alan, Warren

    2005-09-01

    The tolerance to ammonia and nitrites in freshwater ciliate Paramecium bursaria was measured in a conventional open system. The ciliate was exposed to different concentrations of ammonia and nitrites for 2h and 12h in order to determine the lethal concentrations. Linear regression analysis revealed that the 2h-LC50 value for ammonia was 95.94 mg/L and for nitrite 27.35 mg/L using probit scale method (with 95% confidence intervals). There was a linear correlation between the mortality probit scale and logarithmic concentration of ammonia which fit by a regression equation y=7.32 x 9.51 ( R 2=0.98; y, mortality probit scale; x, logarithmic concentration of ammonia), by which 2 h-LC50 value for ammonia was found to be 95.50 mg/L. A linear correlation between mortality probit scales and logarithmic concentration of nitrite is also followed the regression equation y=2.86 x+0.89 ( R 2=0.95; y, mortality probit scale; x, logarithmic concentration of nitrite). The regression analysis of toxicity curves showed that the linear correlation between exposed time of ammonia-N LC50 value and ammonia-N LC50 value followed the regression equation y=2 862.85 e -0.08 x ( R 2=0.95; y, duration of exposure to LC50 value; x, LC50 value), and that between exposed time of nitrite-N LC50 value and nitrite-N LC50 value followed the regression equation y=127.15 e -0.13 x ( R 2=0.91; y, exposed time of LC50 value; x, LC50 value). The results demonstrate that the tolerance to ammonia in P. bursaria is considerably higher than that of the larvae or juveniles of some metozoa, e.g. cultured prawns and oysters. In addition, ciliates, as bacterial predators, are likely to play a positive role in maintaining and improving water quality in aquatic environments with high-level ammonium, such as sewage treatment systems.

  8. [Nutritional value of sesame seeds].

    PubMed

    Martinchik, A N

    2011-01-01

    Literature data on the nutritional value of sesame seeds (Sesamum indicum L.), their use in feeding the world population and food production are presented. Sesame seeds contain up to 55% oil and 20% protein. Sesame proteins are limited by lysine but rich in tryptophan and methionine. Sesame oil is rich in linoleic and oleic acids, the predominance of gamma-tocopherol over the other isomers of vitamin E and high content of fat-soluble lignans (sesamin and sesamolin). Thanks to recent sesame oil has a phytoestrogen activity; it has a cholesterol-lowering effect.

  9. Value basis for conservation policy

    SciTech Connect

    Leiss, W.

    1981-01-01

    This paper is a case study in attempting to apply a particular value (caring) to the domain of social policy, specifically resource conservation policy. The argument is that our consumer society erodes the social basis for the development by individuals of a sense of well-being and personal identity, and that a conservation ethic based on the concept of caring could provide a foundation in practical morality and public policy for a viable sense of well-being. Conservation, then, goes beyond eliminating wasteful consumption to encompass a public commitment that can further economic and social goals. 11 references.

  10. Medical science and social values.

    PubMed

    Caton, D

    2004-07-01

    Social Values, no less than medical science, have shaped the medical management of the pain of childbirth. Nineteenth century feminists fought for greater use of anesthesia in obstetrics at a time when physicians held back for fear of its effects on labor, hemorrhage, rates of infection and the condition of the child. A century later, after physicians became comfortable with the use of anesthesia, a new generation of feminists challenged the use of such drugs, once again citing social considerations. The personalities of colorful and charismatic obstetricians such as James Young Simpson and Grantley Dick-Read played a strong part in the outcome of each confrontation. PMID:15321396

  11. Valuing vaccines: deficiencies and remedies.

    PubMed

    Bloom, David E

    2015-06-01

    Current evaluation models for the value of vaccines typically account for a small subset of the full social and economic benefits of vaccination. Health investments yield positive economic benefits via several channels at the household, community, and national levels. Underestimating, or worse, not considering these benefits can lead to ill-founded recommendations regarding the introduction of vaccines into immunization programs. The clear and strong links between health and wealth suggest the need to redesign valuation frameworks for vaccination so that the full costs may be properly weighed against the full benefits of vaccines.

  12. The complex structured singular value

    NASA Technical Reports Server (NTRS)

    Packard, A.; Doyle, J.

    1993-01-01

    A tutorial introduction to the complex structured singular value (mu) is presented, with an emphasis on the mathematical aspects of mu. The mu-based methods discussed here have been useful for analyzing the performance and robustness properties of linear feedback systems. Several tests for robust stability and performance with computable bounds for transfer functions and their state space realizations are compared, and a simple synthesis problem is studied. Uncertain systems are represented using linear fractional transformations which naturally unify the frequency-domain and state space methods.

  13. Influence of dissolved organic matter on acute toxicity of zinc to larval fathead minnows (Pimephales promelas).

    PubMed

    Bringolf, Robert B; Morris, Brady A; Boese, Connie J; Santore, Robert C; Allen, Herbert E; Meyer, Joseph S

    2006-10-01

    We conducted laboratory toxicity tests in support of the development of a biotic ligand model (BLM) to predict acute toxicity of zinc (Zn) to fathead minnows (Pimephales promelas). To test the effect of dissolved organic matter (DOM) on Zn toxicity, we exposed larval fathead minnows to Zn in water containing elevated concentrations of dissolved organic carbon (DOC) in 96-h static-renewal toxicity tests. We tested DOM isolated from four surface waters: Cypress Swamp, Delaware; Edisto River, South Carolina; Suwannee River, Georgia; and Wilmington, Delaware, wastewater treatment effluent. The DOM isolates from the Edisto River and Wilmington wastewater treatment effluent contained elevated concentrations of NaCl (20-110x control NaCl) due to the use of a Na+-exchange resin to remove Ca2+ and Mg2+ during the DOM isolation process. Therefore, we also performed Zn toxicity tests in which we added up to 20 mM NaCl to exposure solutions containing Cypress Swamp and Suwannee River DOM. A threshold concentration of 11 mg DOC/L was needed to decrease Zn toxicity, after which the 96 h Zn LC50 was positively correlated with DOC concentration. Elevated NaCl concentrations did not alter Zn toxicity in the presence of DOM. In conjunction with data from other studies with fish and invertebrates, results of this study were used to calibrate Version 2.1.1 of the Zn BLM. BLM-predicted LC50s for our exposure waters containing elevated DOM concentrations were within the range of acceptable deviation relative to the observed LC50s (i.e., 0.5-2x observed LC50s); however, BLM-predicted LC50s for our exposure waters containing < 1 mg DOC/L were 2-3x lower than the observed LC50s (i.e., the BLM over-predicted the toxicity). Therefore, the current composite-species BLM for Zn could be improved for fathead minnows if that species were modeled separately from the other species used to calibrate Version 2.1.1. PMID:16788742

  14. Valuing and selling a practice.

    PubMed

    Sullivan, Walter

    2012-11-01

    Surgeons, as they contemplate retirement, wrongly believe that their practices do not have financial value. In fact, a well-organized efficiently functioning office with an emphasis on excellent service in combination with a constant stream of patients make it financially ideal for the new surgeon. Being able to assume such a practice can be a very smart financial decision. The practice's worth can be determined by a careful analysis of the practice financials and an evaluation of the functioning of the office and employees. Purchasing such a practice can be, economically, a very smart move by a new surgeon. Payments are made over time at a rate that allows the surgeon to make a good living, leaving him with real equity once the payments are complete. The departing surgeon, who had spent years building this successful practice, gets some of this value back in the form of an income stream to supplement his retirement. This process should be considered in virtually every case. Do not just "close the door."

  15. The "trophic" value of foods.

    PubMed

    Williams, R J; Heffley, J D; Yew, M L; Bode, C W

    1973-03-01

    Foods must furnish (i) calories, which can readily be measured, and (ii) raw materials necessary for the building and maintenance of metabolic machinery which makes possible fuel utilization. We have called this "beyond-calorie" quality of food its "trophic" value. This concept has more unity than appears on the surface, and is capable of approximate measurement by biological testing as our experiments show. The trophic value of a food cannot be ascertained from food composition tables because only a smattering of the necessary information is commonly furnished. A food cannot support life if it is missing, or deficient with respect to, any one of the necessary nutrients. A tabulation which includes only a few nutrients-e.g., calcium, thiamin, riboflavin, niacin, phosphorus, and iron-can be woefully misleading, especially if these individual nutrients have been added by way of fortification. THE MEASUREMENT WE HAVE APPLIED TO A NUMBER OF FOODS IS POTENTIALLY VALUABLE FOR COMPARING SIMILAR FOOD PRODUCTS: two grains, two breads, two milk products, or for comparison of the same food grown, processed, or preserved in different ways. By using essentially this method we have found that barnyard eggs are somewhat superior to battery eggs, but that whether they are fertile or infertile makes no difference. We are of the opinion that extensive biological testing of many commercial food products is highly desirable to help promote human health and better internal environments for our cells and tissues.

  16. Total Value of Phosphorus Recovery.

    PubMed

    Mayer, Brooke K; Baker, Lawrence A; Boyer, Treavor H; Drechsel, Pay; Gifford, Mac; Hanjra, Munir A; Parameswaran, Prathap; Stoltzfus, Jared; Westerhoff, Paul; Rittmann, Bruce E

    2016-07-01

    Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies.

  17. Total Value of Phosphorus Recovery.

    PubMed

    Mayer, Brooke K; Baker, Lawrence A; Boyer, Treavor H; Drechsel, Pay; Gifford, Mac; Hanjra, Munir A; Parameswaran, Prathap; Stoltzfus, Jared; Westerhoff, Paul; Rittmann, Bruce E

    2016-07-01

    Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies. PMID:27214029

  18. Human values in medical education.

    PubMed

    Ellis, J R

    1976-11-01

    Attitudes and values in medicine vary with the nature of the individual, his education and training, and the circumstances of his professional life. Comparisons are drawn between medical education in Britain 40 years ago and today. Though education has changed, British students are still mainly motivated by a desire to care for sick people. The impact of personal medicine on a country that has long accepted the need for some kind of national health service is described. It is postulated that as government and public become increasingly involved in health care, it is of paramount importance that medical education should provide a clear understanding of what a profession is and inculcate a determination to maintain true professional status. New responsibilities of the profession, to the public at large and to society, are suggested. The ability of medical education to exert a good influence on concern for human values in medicine depends in the final analysis on the ability to show excellence to medical students.

  19. Manifold-valued Dirichlet Processes

    PubMed Central

    Kim, Hyunwoo J.; Xu, Jia; Vemuri, Baba C.; Singh, Vikas

    2016-01-01

    Statistical models for manifold-valued data permit capturing the intrinsic nature of the curved spaces in which the data lie and have been a topic of research for several decades. Typically, these formulations use geodesic curves and distances defined locally for most cases — this makes it hard to design parametric models globally on smooth manifolds. Thus, most (manifold specific) parametric models available today assume that the data lie in a small neighborhood on the manifold. To address this ‘locality’ problem, we propose a novel nonparametric model which unifies multivariate general linear models (MGLMs) using multiple tangent spaces. Our framework generalizes existing work on (both Euclidean and non-Euclidean) general linear models providing a recipe to globally extend the locally-defined parametric models (using a mixture of local models). By grouping observations into sub-populations at multiple tangent spaces, our method provides insights into the hidden structure (geodesic relationships) in the data. This yields a framework to group observations and discover geodesic relationships between covariates X and manifold-valued responses Y, which we call Dirichlet process mixtures of multivariate general linear models (DP-MGLM) on Riemannian manifolds. Finally, we present proof of concept experiments to validate our model. PMID:26973982

  20. Student Views on the Value of Feedback

    ERIC Educational Resources Information Center

    Marie, Jenny A.

    2016-01-01

    This paper investigates the value that a sample of students placed on feedback, what they valued it for and the conditions that affected this value judgement. I show that not all students value feedback particularly highly, especially when considered in relation to other factors in their education and when considered for its intrinsic value as…