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Sample records for similar retention times

  1. Drug Retention Times

    Energy Technology Data Exchange (ETDEWEB)

    Center for Human Reliability Studies

    2007-05-01

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user.

  2. Drug Retention Times

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2007-05-01

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user. Based on anecdotal evidence, most people “party” during extended time away from the work environment. Therefore, the following scenarios were envisioned: (1) a person uses an illicit drug at a party on Saturday night (infrequent user); (2) a person uses a drug one time on Friday night and once again on Saturday night (infrequent user); and (3) a person uses a drug on Friday night, uses a drug twice on Saturday night, and once again on Sunday (frequent user).

  3. Changing times, similar challenges.

    Science.gov (United States)

    Baillie, Jonathan

    2013-11-01

    With IHEEM celebrating its 70th Anniversary this month, HEJ editor, Jonathan Baillie, recently met the Institute's oldest surviving Past-President, Lawrence Turner OBE, who, having in 1964 established a small engineering business producing some of the NHS's earliest nurse call systems from the basement of his three-storey West Midlands home, has since seen the company, Static Systems Group, grow to become one of the U.K. market-leaders in its field. The Institute's President from 1979-1981, he looked back, during a fascinating two-hour discussion, at his time in the role, talked through some of the key technological and other changes he has seen in the past five decades, reflected on an interesting and varied career, and considered some of the very different current-day challenges that today's IHEEM President, and the Institute as a whole, face.

  4. Towards a chromatographic similarity index to establish localised quantitative structure-retention relationships for retention prediction. II Use of Tanimoto similarity index in ion chromatography.

    Science.gov (United States)

    Park, Soo Hyun; Talebi, Mohammad; Amos, Ruth I J; Tyteca, Eva; Haddad, Paul R; Szucs, Roman; Pohl, Christopher A; Dolan, John W

    2017-11-10

    Quantitative Structure-Retention Relationships (QSRR) are used to predict retention times of compounds based only on their chemical structures encoded by molecular descriptors. The main concern in QSRR modelling is to build models with high predictive power, allowing reliable retention prediction for the unknown compounds across the chromatographic space. With the aim of enhancing the prediction power of the models, in this work, our previously proposed QSRR modelling approach called "federation of local models" is extended in ion chromatography to predict retention times of unknown ions, where a local model for each target ion (unknown) is created using only structurally similar ions from the dataset. A Tanimoto similarity (TS) score was utilised as a measure of structural similarity and training sets were developed by including ions that were similar to the target ion, as defined by a threshold value. The prediction of retention parameters (a- and b-values) in the linear solvent strength (LSS) model in ion chromatography, log k=a - blog[eluent], allows the prediction of retention times under all eluent concentrations. The QSRR models for a- and b-values were developed by a genetic algorithm-partial least squares method using the retention data of inorganic and small organic anions and larger organic cations (molecular mass up to 507) on four Thermo Fisher Scientific columns (AS20, AS19, AS11HC and CS17). The corresponding predicted retention times were calculated by fitting the predicted a- and b-values of the models into the LSS model equation. The predicted retention times were also plotted against the experimental values to evaluate the goodness of fit and the predictive power of the models. The application of a TS threshold of 0.6 was found to successfully produce predictive and reliable QSRR models (Q ext(F2) 2 >0.8 and Mean Absolute Error<0.1), and hence accurate retention time predictions with an average Mean Absolute Error of 0.2min. Crown Copyright

  5. Lesser Neural Pattern Similarity across Repeated Tests Is Associated with Better Long-Term Memory Retention.

    Science.gov (United States)

    Karlsson Wirebring, Linnea; Wiklund-Hörnqvist, Carola; Eriksson, Johan; Andersson, Micael; Jonsson, Bert; Nyberg, Lars

    2015-07-01

    Encoding and retrieval processes enhance long-term memory performance. The efficiency of encoding processes has recently been linked to representational consistency: the reactivation of a representation that gets more specific each time an item is further studied. Here we examined the complementary hypothesis of whether the efficiency of retrieval processes also is linked to representational consistency. Alternatively, recurrent retrieval might foster representational variability--the altering or adding of underlying memory representations. Human participants studied 60 Swahili-Swedish word pairs before being scanned with fMRI the same day and 1 week later. On Day 1, participants were tested three times on each word pair, and on Day 7 each pair was tested once. A BOLD signal change in right superior parietal cortex was associated with subsequent memory on Day 1 and with successful long-term retention on Day 7. A representational similarity analysis in this parietal region revealed that beneficial recurrent retrieval was associated with representational variability, such that the pattern similarity on Day 1 was lower for retrieved words subsequently remembered compared with those subsequently forgotten. This was mirrored by a monotonically decreased BOLD signal change in dorsolateral prefrontal cortex on Day 1 as a function of repeated successful retrieval for words subsequently remembered, but not for words subsequently forgotten. This reduction in prefrontal response could reflect reduced demands on cognitive control. Collectively, the results offer novel insights into why memory retention benefits from repeated retrieval, and they suggest fundamental differences between repeated study and repeated testing. Repeated testing is known to produce superior long-term retention of the to-be-learned material compared with repeated encoding and other learning techniques, much because it fosters repeated memory retrieval. This study demonstrates that repeated memory

  6. Wind Effects on Retention Time in Highway Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Rasmussen, Michael R.

    2007-01-01

    is to evaluate the quality of long term simulations based on historical rain series of the pollutant discharges from roads and highways. The idea of this paper is to evaluate the effects of wind on the retention time and compare the retention time for the situation of a spatial uniform wind shear stress...... with the situation of a "real" spatial non-uniform shear stress distribution on the surface of the pond. The result of this paper shows that wind plays a dominant role for the retention time and flow pattern. Furthermore, the results shows that the differences in retention time between the use of uniform and non...

  7. Wind Effects on Retention Time in Highway Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Rasmussen, Michael R.

    2008-01-01

    is to evaluate the quality of long term simulations based on historical rain series of the pollutant discharges from roads and highways. The idea of this paper is to evaluate the effects of wind on the retention time and compare the retention time for the situation of a spatial uniform wind shear stress...... with the situation of a "real" spatial non-uniform shear stress distribution on the surface of the pond. The result of this paper shows that wind plays a dominant role for the retention time and flow pattern. Furthermore, the results shows that the differences in retention time between the use of uniform and non...

  8. Effect of Retention Time on Biogas Production from Poultry ...

    African Journals Online (AJOL)

    A study was carried out on different retention times in the anaerobic fermentation of slurry from poultry droppings and cassava peels. The system adopted in this work was batch-type. Daily gas production fell slightly from 130 to 32 litres as retention time was increased from 10 to 40 days for poultry droppings. For cassava ...

  9. Extrapolation of animal radionuclide retention data to man: Use of similarity ratios

    International Nuclear Information System (INIS)

    Thomas, J.M.; Eberhardt, L.L.

    1976-01-01

    A major problem in toxicology is the need for testing a myriad possible substances on several animal species as an aid in establishing standards for man. Particular interest in the problem of extrapolation to man is linked to a need for a method of obtaining transfer coefficients in food-chain models of ecosystems. Such a method could circumvent the necessity to test many species and compounds. Because of their particular interest in radioecology, the authors' studies were initiated using radionuclide retention data available in the literature. Since radionuclide retention should be a function of metabolism it follows that direct or indirect measures could be described by a ''power law'' based on body weight of the organism(s). However, when such power laws have been extended to interspecies comparisons the resulting power coefficients are usually substantially less than the value anticipated and seem to be different for each radionuclide. This paper proposes that interspecies comparisons ought to be based on the proportionality coefficient rather than the power parameter of the power function model and have called pairwise comparisons amongst species ''similarity ratios''. Retention data were examined from five non-ruminant species (including man) where several radionuclides with different physical properties were fed. Subsequently an expression was devised whereby an estimate of biological equilibrium level in man could be calculated using similar estimates from experiments using mice, rats or dogs. There are some statistical questions to resolve which have to do with the assumed frequency distribution for estimates of the proportionality coefficient. In addition, repeated use was made of the same data sets. (author)

  10. Calculation of retention time tolerance windows with absolute confidence from shared liquid chromatographic retention data.

    Science.gov (United States)

    Boswell, Paul G; Abate-Pella, Daniel; Hewitt, Joshua T

    2015-09-18

    Compound identification by liquid chromatography-mass spectrometry (LC-MS) is a tedious process, mainly because authentic standards must be run on a user's system to be able to confidently reject a potential identity from its retention time and mass spectral properties. Instead, it would be preferable to use shared retention time/index data to narrow down the identity, but shared data cannot be used to reject candidates with an absolute level of confidence because the data are strongly affected by differences between HPLC systems and experimental conditions. However, a technique called "retention projection" was recently shown to account for many of the differences. In this manuscript, we discuss an approach to calculate appropriate retention time tolerance windows for projected retention times, potentially making it possible to exclude candidates with an absolute level of confidence, without needing to have authentic standards of each candidate on hand. In a range of multi-segment gradients and flow rates run among seven different labs, the new approach calculated tolerance windows that were significantly more appropriate for each retention projection than global tolerance windows calculated for retention projections or linear retention indices. Though there were still some small differences between the labs that evidently were not taken into account, the calculated tolerance windows only needed to be relaxed by 50% to make them appropriate for all labs. Even then, 42% of the tolerance windows calculated in this study without standards were narrower than those required by WADA for positive identification, where standards must be run contemporaneously. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. RETENTION TIME EFFECT ON METAL REMOVAL BY PEAT COLUMNS

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, E

    2007-02-28

    The potential use of a peat bed to treat the H-12 Outfall discharge to bring it to new compliance limits was previously investigated and reported utilizing a 7 hour retention time. The influence of retention time (contact time) of water with peat moss on the removal of copper from the water was investigated under laboratory conditions using vertical flow peat moss columns. Reduction of the necessary retention time has a large influence on the design sizing of any peat bed that would be constructed to treat the H-12 discharge on a full scale basis. Retention times of 5 hours, 3 hours and 1 hour were tested to determine the copper removal by the peat columns using vertical flow. Water samples were collected after 4, 8, 12, and 16 water volumes had passed through the columns and analyzed for a suite of metals, with quantitative emphasis on copper. Laboratory results indicated that copper removal was very high at each of the 3 retention times tested, ranging from 99.6 % removal at 5 and 3 hours to 98.8% removal at 1 hour. All these values are much lower that the new compliance limit for the outfall. The results also indicated that most divalent metals were removed to their normal reporting detection limit for the analytical methods used, including zinc. Lead levels in the H-12 discharge used in this study were below PQL in all samples analyzed. While each of the retention times studied removed copper very well, there were indications that 1 hour is probably too short for an operational, long-term facility. At that retention time, there was about 6% compaction of the peat in the column due to the water velocity, and this may affect long term hydraulic conductivity of the peat bed. At that retention time, copper concentration in the effluent was higher than the other times tested, although still very low. Because of the potential compacting and somewhat reduced removal efficiency at a 1 hour retention time, it would be prudent to design to at least a 3 hour retention

  12. Improving Retention and Enrollment Forecasting in Part-Time Programs

    Science.gov (United States)

    Shapiro, Joel; Bray, Christopher

    2011-01-01

    This article describes a model that can be used to analyze student enrollment data and can give insights for improving retention of part-time students and refining institutional budgeting and planning efforts. Adult higher-education programs are often challenged in that part-time students take courses less reliably than full-time students. For…

  13. The human body retention time of environmental organically bound tritium

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, John; Bailey, Trevor [Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT (United Kingdom); Reese, Allan [Centre for Environment, Fisheries and Aquaculture Science, The Nothe, Barrack Road, Weymouth, Dorset DT4 8UB (United Kingdom)], E-mail: john.hunt@cefas.co.uk

    2009-03-15

    Tritium in the UK environment causes low radiation doses to the public, but uncertainty exists in the dose coefficient for the organically bound component of tritium (OBT). This can affect the assessment of effective doses to representative persons. Contributing to that uncertainty is poor knowledge of the body retention time of OBT and how this varies for different OBT compounds in food. This study was undertaken to measure the retention time of tritium by volunteers after eating sole from Cardiff Bay, which may contain OBT from discharges from the GE Healthcare Ltd plant. Five volunteers provided samples of excreta over periods up to 150 days after intake. The results, which are presented in raw form to allow independent analysis, suggest retention of total tritium with body half-times ranging from 4 to 11 days, with no evidence (subject to experimental noise) of a significant contribution due to retention with a longer half-time. This range covers the half-time of 10 days used by the ICRP for tritiated water. The short timescale could be due to rapid hydrolysis in body tissues of the particular form of OBT used in this study. Implications for the dose coefficient for OBT are that the use of the ICRP value of 4.2 x 10{sup -11} Sv Bq{sup -1} may be cautious in this specific situation. These observations on dose coefficients are separate from any implications of recent discussion on whether the tritium radiation weighting factor should be increased from 1 to 2.

  14. Effect of Retention Time on Biogas Production from Poultry ...

    African Journals Online (AJOL)

    JPC

    Daily gas production fell slightly from 130 to 32 litres as retention time was ... The continuing energy crisis has reawakened interest in the anaerobic ... and hydrogen sulfide (H2S2): 0.3 vol.%. ..... Nigerian Journal of Solar Energy 15: 80 – 85.

  15. Apparent mineral retention is similar in control and hyperinsulinemic men after consumption of high amylose cornstarch.

    Science.gov (United States)

    Behall, Kay M; Howe, Juliette C; Anderson, Richard A

    2002-07-01

    The effects on apparent mineral retention after long-term consumption of a high amylose diet containing 30 g resistant starch (RS) were investigated in 10 control and 14 hyperinsulinemic men. Subjects consumed products (bread, muffins, cookies, corn flakes and cheese puffs) made with standard (70% amylopectin, 30% amylose; AP) or high amylose (70% amylose, 30% amylopectin; AM) cornstarch for two 14-wk periods in a crossover pattern. Starch products replaced usual starches in the habitual diet for 10 wk followed by 4 wk of consuming the controlled diets. During wk 12, all urine, feces and duplicate foods were collected for 7 d. Urinary chromium losses after a glucose tolerance test or 24-h collections of the hyperinsulinemic and control subjects did not differ and were not altered by diet. Except for zinc, the two subject types did not differ significantly in apparent mineral balance. Apparent retentions of calcium and magnesium were not significantly affected by diet (AM vs. AP) or type-by-diet interaction. Apparent iron retention tended to be greater after AM than AP consumption (P copper retention was greater after consuming AP than after AM (P < 0.02), whereas apparent zinc retention was greater after consuming AM than after AP (P < 0.018). Zinc also showed a significant type-by-diet interaction (P < 0.034) with control subjects retaining less zinc after consuming AP than after AM. In summary, a high amylose cornstarch diet containing 30 g RS could be consumed long term without markedly affecting, and possibly enhancing, retention of some minerals.

  16. Factors Influencing Retention Among Part-Time Clinical Nursing Faculty.

    Science.gov (United States)

    Carlson, Joanne S

    This study sought to determine job characteristics influencing retention of part-time clinical nurse faculty teaching in pre-licensure nursing education. Large numbers of part-time faculty are needed to educate students in the clinical setting. Faculty retention helps maintain consistency and may positively influence student learning. A national sample of part-time clinical nurse faculty teaching in baccalaureate programs responded to a web-based survey. Respondents were asked to identify the primary reason for wanting or not wanting to continue working for a school of nursing (SON). Affinity for students, pay and benefits, support, and feeling valued were the top three reasons given for continuing to work at an SON. Conflicts with life and other job responsibilities, low pay, and workload were the top three reasons given for not continuing. Results from this study can assist nursing programs in finding strategies to help reduce attrition among part-time clinical faculty.

  17. Engaging narratives evoke similar neural activity and lead to similar time perception.

    Science.gov (United States)

    Cohen, Samantha S; Henin, Simon; Parra, Lucas C

    2017-07-04

    It is said that we lose track of time - that "time flies" - when we are engrossed in a story. How does engagement with the story cause this distorted perception of time, and what are its neural correlates? People commit both time and attentional resources to an engaging stimulus. For narrative videos, attentional engagement can be represented as the level of similarity between the electroencephalographic responses of different viewers. Here we show that this measure of neural engagement predicted the duration of time that viewers were willing to commit to narrative videos. Contrary to popular wisdom, engagement did not distort the average perception of time duration. Rather, more similar brain responses resulted in a more uniform perception of time across viewers. These findings suggest that by capturing the attention of an audience, narrative videos bring both neural processing and the subjective perception of time into synchrony.

  18. A Study Similarities and Differences in Selected Human Resource Practices and Their Relation to Teacher Retention in a Sample of Four School Districts, Two with High and Two with Low Rates of Retention

    Science.gov (United States)

    Phelan, Patrick M.

    2010-01-01

    This is a study of the practices utilized by four school districts, two with high and two with low retention rates of teachers, to examine how similarities and differences in selected human resources practices relate to the successful retention of teachers in these districts. The factors studied that may impact teacher retention included…

  19. Testing the shape-similarity hypothesis between particle-size distribution and water retention for Sicilian soils

    Directory of Open Access Journals (Sweden)

    Chiara Antinoro

    2012-12-01

    Full Text Available Application of the Arya and Paris (AP model to estimate the soil water retention curve requires a detailed description of the particlesize distribution (PSD but limited experimental PSD data are generally determined by the conventional sieve-hydrometer (SH method. Detailed PSDs can be obtained by fitting a continuous model to SH data or performing measurements by the laser diffraction (LD method. The AP model was applied to 40 Sicilian soils for which the PSD was measured by both the SH and LD methods. The scale factor was set equal to 1.38 (procedure AP1 or estimated by a logistical model with parameters gathered from literature (procedure AP2. For both SH and LD data, procedure AP2 allowed a more accurate prediction of the water retention than procedure AP1, confirming that it is not convenient to use a unique value of  for soils that are very different in texture. Despite the differences in PSDs obtained by the SH and LD methods, the water retention predicted by a given procedure (AP1 or AP2 using SH or LD data was characterized by the same level of accuracy. Discrepancies in the estimated water retention from the two PSD measurement methods were attributed to underestimation of the finest diameter frequency obtained by the LD method. Analysis also showed that the soil water retention estimated using the SH method was affected by an estimation bias that could be corrected by an optimization procedure (OPT. Comparison of a-distributions and water retention shape indices obtained by the two methods (SH or LD indicated that the shape-similarity hypothesis is better verified if the traditional sieve-hydrometer data are used to apply the AP model. The optimization procedure allowed more accurate predictions of the water retention curves than the traditional AP1 and AP2 procedures. Therefore, OPT can be considered a valid alternative to the more complex logistical model for estimating the water retention curve of Sicilian soils.

  20. Bryophyte species richness on retention aspens recovers in time but community structure does not.

    Science.gov (United States)

    Oldén, Anna; Ovaskainen, Otso; Kotiaho, Janne S; Laaka-Lindberg, Sanna; Halme, Panu

    2014-01-01

    Green-tree retention is a forest management method in which some living trees are left on a logged area. The aim is to offer 'lifeboats' to support species immediately after logging and to provide microhabitats during and after forest re-establishment. Several studies have shown immediate decline in bryophyte diversity after retention logging and thus questioned the effectiveness of this method, but longer term studies are lacking. Here we studied the epiphytic bryophytes on European aspen (Populus tremula L.) retention trees along a 30-year chronosequence. We compared the bryophyte flora of 102 'retention aspens' on 14 differently aged retention sites with 102 'conservation aspens' on 14 differently aged conservation sites. We used a Bayesian community-level modelling approach to estimate the changes in bryophyte species richness, abundance (area covered) and community structure during 30 years after logging. Using the fitted model, we estimated that two years after logging both species richness and abundance of bryophytes declined, but during the following 20-30 years both recovered to the level of conservation aspens. However, logging-induced changes in bryophyte community structure did not fully recover over the same time period. Liverwort species showed some or low potential to benefit from lifeboating and high potential to re-colonise as time since logging increases. Most moss species responded similarly, but two cushion-forming mosses benefited from the logging disturbance while several weft- or mat-forming mosses declined and did not re-colonise in 20-30 years. We conclude that retention trees do not function as equally effective lifeboats for all bryophyte species but are successful in providing suitable habitats for many species in the long-term. To be most effective, retention cuts should be located adjacent to conservation sites, which may function as sources of re-colonisation and support the populations of species that require old-growth forests.

  1. Bryophyte species richness on retention aspens recovers in time but community structure does not.

    Directory of Open Access Journals (Sweden)

    Anna Oldén

    Full Text Available Green-tree retention is a forest management method in which some living trees are left on a logged area. The aim is to offer 'lifeboats' to support species immediately after logging and to provide microhabitats during and after forest re-establishment. Several studies have shown immediate decline in bryophyte diversity after retention logging and thus questioned the effectiveness of this method, but longer term studies are lacking. Here we studied the epiphytic bryophytes on European aspen (Populus tremula L. retention trees along a 30-year chronosequence. We compared the bryophyte flora of 102 'retention aspens' on 14 differently aged retention sites with 102 'conservation aspens' on 14 differently aged conservation sites. We used a Bayesian community-level modelling approach to estimate the changes in bryophyte species richness, abundance (area covered and community structure during 30 years after logging. Using the fitted model, we estimated that two years after logging both species richness and abundance of bryophytes declined, but during the following 20-30 years both recovered to the level of conservation aspens. However, logging-induced changes in bryophyte community structure did not fully recover over the same time period. Liverwort species showed some or low potential to benefit from lifeboating and high potential to re-colonise as time since logging increases. Most moss species responded similarly, but two cushion-forming mosses benefited from the logging disturbance while several weft- or mat-forming mosses declined and did not re-colonise in 20-30 years. We conclude that retention trees do not function as equally effective lifeboats for all bryophyte species but are successful in providing suitable habitats for many species in the long-term. To be most effective, retention cuts should be located adjacent to conservation sites, which may function as sources of re-colonisation and support the populations of species that require old

  2. An Energy-Based Similarity Measure for Time Series

    Directory of Open Access Journals (Sweden)

    Pierre Brunagel

    2007-11-01

    Full Text Available A new similarity measure, called SimilB, for time series analysis, based on the cross-ΨB-energy operator (2004, is introduced. ΨB is a nonlinear measure which quantifies the interaction between two time series. Compared to Euclidean distance (ED or the Pearson correlation coefficient (CC, SimilB includes the temporal information and relative changes of the time series using the first and second derivatives of the time series. SimilB is well suited for both nonstationary and stationary time series and particularly those presenting discontinuities. Some new properties of ΨB are presented. Particularly, we show that ΨB as similarity measure is robust to both scale and time shift. SimilB is illustrated with synthetic time series and an artificial dataset and compared to the CC and the ED measures.

  3. Optimal Retention Level for Infinite Time Horizons under MADM

    Directory of Open Access Journals (Sweden)

    Başak Bulut Karageyik

    2016-12-01

    Full Text Available In this paper, we approximate the aggregate claims process by using the translated gamma process under the classical risk model assumptions, and we investigate the ultimate ruin probability. We consider optimal reinsurance under the minimum ultimate ruin probability, as well as the maximum benefit criteria: released capital, expected profit and exponential-fractional-logarithmic utility from the insurer’s point of view. Numerical examples are presented to explain how the optimal initial surplus and retention level are changed according to the individual claim amounts, loading factors and weights of the criteria. In the decision making process, we use The Analytical Hierarchy Process (AHP and The Technique for Order of Preference by Similarity to ideal Solution (TOPSIS methods as the Multi-Attribute Decision Making methods (MADM and compare our results considering different combinations of loading factors for both exponential and Pareto individual claims.

  4. Similarity estimators for irregular and age uncertain time series

    Science.gov (United States)

    Rehfeld, K.; Kurths, J.

    2013-09-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many datasets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age uncertain time series. We compare the Gaussian-kernel based cross correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  5. Similarity estimators for irregular and age-uncertain time series

    Science.gov (United States)

    Rehfeld, K.; Kurths, J.

    2014-01-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many data sets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age-uncertain time series. We compare the Gaussian-kernel-based cross-correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case, coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  6. Effect of hydraulic retention time on continuous biocatalytic calcification reactor

    International Nuclear Information System (INIS)

    Isik, Mustafa; Altas, Levent; Kurmac, Yakup; Ozcan, Samet; Oruc, Ozcan

    2010-01-01

    High calcium concentrations in the wastewaters are problematic, because they lead to clogging of pipelines, boilers and heat exchangers through scaling (as carbonate, sulfate or phosphate precipitates), or malfunctioning of aerobic and anaerobic reactors. As a remedy to this problem, the industry typically uses chemical crystallization reactors which are efficient but often require complex monitoring and control and, as a drawback, can give rise to highly alkaline effluents. Biomineralization are emerging as alternative mechanisms for the removal of calcium from aqueous environments. Biocatalytic calcification reactors (BCR) utilize microbial urea hydrolysis by bacteria for the removal of calcium, as calcite, from industrial wastewater. Hydraulic retention time (HRT) effect on calcium removal was studied with a continuous feed BCR reactor treating a simulated pulp paper wastewater. Study showed that HRT is important parameter and HRT of 5-6 h is optimum for calcium removal from calcium-rich wastewaters.

  7. Tokunaga self-similarity arises naturally from time invariance

    Science.gov (United States)

    Kovchegov, Yevgeniy; Zaliapin, Ilya

    2018-04-01

    The Tokunaga condition is an algebraic rule that provides a detailed description of the branching structure in a self-similar tree. Despite a solid empirical validation and practical convenience, the Tokunaga condition lacks a theoretical justification. Such a justification is suggested in this work. We define a geometric branching process G (s ) that generates self-similar rooted trees. The main result establishes the equivalence between the invariance of G (s ) with respect to a time shift and a one-parametric version of the Tokunaga condition. In the parameter region where the process satisfies the Tokunaga condition (and hence is time invariant), G (s ) enjoys many of the symmetries observed in a critical binary Galton-Watson branching process and reproduces the latter for a particular parameter value.

  8. Similarity Solutions for Multiterm Time-Fractional Diffusion Equation

    OpenAIRE

    Elsaid, A.; Abdel Latif, M. S.; Maneea, M.

    2016-01-01

    Similarity method is employed to solve multiterm time-fractional diffusion equation. The orders of the fractional derivatives belong to the interval (0,1] and are defined in the Caputo sense. We illustrate how the problem is reduced from a multiterm two-variable fractional partial differential equation to a multiterm ordinary fractional differential equation. Power series solution is obtained for the resulting ordinary problem and the convergence of the series solution is discussed. Based on ...

  9. Estimating retention potential of headwater catchment using Tritium time series

    Science.gov (United States)

    Hofmann, Harald; Cartwright, Ian; Morgenstern, Uwe

    2018-06-01

    Headwater catchments provide substantial streamflow to rivers even during long periods of drought. Documenting the mean transit times (MTT) of stream water in headwater catchments and therefore the retention capacities of these catchments is crucial for water management. This study uses time series of 3H activities in combination with major ion concentrations, stable isotope ratios and radon activities (222Rn) in the Lyrebird Creek catchment in Victoria, Australia to provide a unique insight into the mean transit time distributions and flow systems of this small temperate headwater catchment. At all streamflows, the stream has 3H activities (water in the stream is derived from stores with long transit times. If the water in the catchment can be represented by a single store with a continuum of ages, mean transit times of the stream water range from ∼6 up to 40 years, which indicates the large retention potential for this catchment. Alternatively, variations of 3H activities, stable isotopes and major ions can be explained by mixing between of young recent recharge and older water stored in the catchment. While surface runoff is negligible, the variation in stable isotope ratios, major ion concentrations and radon activities during most of the year is minimal (±12%) and only occurs during major storm events. This suggests that different subsurface water stores are activated during the storm events and that these cease to provide water to the stream within a few days or weeks after storm events. The stores comprise micro and macropore flow in the soils and saprolite as well as the boundary between the saprolite and the fractured bed rock. Hydrograph separations from three major storm events using Tritium, electrical conductivity and selected major ions as well a δ18O suggest a minimum of 50% baseflow at most flow conditions. We demonstrate that headwater catchments can have a significant storage capacity and that the relationship between long-water stores and

  10. Similarity Solutions for Multiterm Time-Fractional Diffusion Equation

    Directory of Open Access Journals (Sweden)

    A. Elsaid

    2016-01-01

    Full Text Available Similarity method is employed to solve multiterm time-fractional diffusion equation. The orders of the fractional derivatives belong to the interval (0,1] and are defined in the Caputo sense. We illustrate how the problem is reduced from a multiterm two-variable fractional partial differential equation to a multiterm ordinary fractional differential equation. Power series solution is obtained for the resulting ordinary problem and the convergence of the series solution is discussed. Based on the obtained results, we propose a definition for a multiterm error function with generalized coefficients.

  11. Timing of quizzes during learning: Effects on motivation and retention.

    Science.gov (United States)

    Healy, Alice F; Jones, Matt; Lalchandani, Lakshmi A; Tack, Lindsay Anderson

    2017-06-01

    This article investigates how the timing of quizzes given during learning impacts retention of studied material. We investigated the hypothesis that interspersing quizzes among study blocks increases student engagement, thus improving learning. Participants learned 8 artificial facts about each of 8 plant categories, with the categories blocked during learning. Quizzes about 4 of the 8 facts from each category occurred either immediately after studying the facts for that category (standard) or after studying the facts from all 8 categories (postponed). In Experiment 1, participants were given tests shortly after learning and several days later, including both the initially quizzed and unquizzed facts. Test performance was better in the standard than in the postponed condition, especially for categories learned later in the sequence. This result held even for the facts not quizzed during learning, suggesting that the advantage cannot be due to any direct testing effects. Instead the results support the hypothesis that interrupting learning with quiz questions is beneficial because it can enhance learner engagement. Experiment 2 provided further support for this hypothesis, based on participants' retrospective ratings of their task engagement during the learning phase. These findings have practical implications for when to introduce quizzes in the classroom. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  12. Initial polishing time affects gloss retention in resin composites.

    Science.gov (United States)

    Waheeb, Nehal; Silikas, Nick; Watts, David

    2012-10-01

    To determine the effect of finishing and polishing time on the surface gloss of various resin-composites before and after simulated toothbrushing. Eight representative resin-composites (Ceram X mono, Ceram X duo, Tetric EvoCeram, Venus Diamond, EsteliteSigma Quick, Esthet.X HD, Filtek Supreme XT and Spectrum TPH) were used to prepare 80 disc-shaped (12 mm x 2 mm) specimens. The two step system Venus Supra was used for polishing the specimens for 3 minutes (Group A) and 10 minutes (Group B). All specimens were subjected to 16,000 cycles of simulated toothbrushing. The surface gloss was measured after polishing and after brushing using the gloss meter. Results were evaluated using one way ANOVA, two ways ANOVA and Dennett's post hoc test (P = 0.05). Group B (10-minute polishing) resulted in higher gloss values (GV) for all specimens compared to Group A (3 minutes). Also Group B showed better gloss retention compared to Group A after simulated toothbrushing. In each group, there was a significant difference between the polished composite resins (P gloss after the simulated toothbrushing.

  13. Bronchoscopic assessment of airway retention time of aerosolized xylitol

    Science.gov (United States)

    Durairaj, Lakshmi; Neelakantan, Srividya; Launspach, Janice; Watt, Janet L; Allaman, Margaret M; Kearney, William R; Veng-Pedersen, Peter; Zabner, Joseph

    2006-01-01

    Background Human airway surface liquid (ASL) has abundant antimicrobial peptides whose potency increases as the salt concentration decreases. Xylitol is a 5-carbon sugar that has the ability to lower ASL salt concentration, potentially enhancing innate immunity. Xylitol was detected for 8 hours in the ASL after application in airway epithelium in vitro. We tested the airway retention time of aerosolized iso-osmotic xylitol in healthy volunteers. Methods After a screening spirometry, volunteers received 10 ml of nebulized 5% xylitol. Bronchoscopy was done at 20 minutes (n = 6), 90 minutes (n = 6), and 3 hours (n = 5) after nebulization and ASL was collected using microsampling probes, followed by bronchoalveolar lavage (BAL). Xylitol concentration was measured by nuclear magnetic resonance spectroscopy and corrected for dilution using urea concentration. Results All subjects tolerated nebulization and bronchoscopy well. Mean ASL volume recovered from the probes was 49 ± 23 μl. The mean ASL xylitol concentration at 20, 90, and 180 minutes was 1.6 ± 1.9 μg/μl, 0.6 ± 0.6 μg/μl, and 0.1 ± 0.1 μg/μl, respectively. Corresponding BAL concentration corrected for dilution was consistently lower at all time points. The terminal half-life of aerosolized xylitol obtained by the probes was 45 minutes with a mean residence time of 65 minutes in ASL. Corresponding BAL values were 36 and 50 minutes, respectively. Conclusion After a single dose nebulization, xylitol was detected in ASL for 3 hours, which was shorter than our in vitro measurement. The microsampling probe performed superior to BAL when sampling bronchial ASL. PMID:16483382

  14. Retention of Idioms Following One-Time Exposure

    Science.gov (United States)

    Reuterskiold, Christina; Van Lancker Sidtis, Diana

    2013-01-01

    This study explored retention of idioms and novel (i.e. newly created or grammatically generated) expressions in English-speaking girls following exposure only once during a conversation. Our hypothesis was that idioms, because of their inherent holistic, nonliteral and social characteristics, are acquired differently and more rapidly than novel…

  15. The Effect of Graduate Education Timing on the Retention of Surface Warfare Officers

    Science.gov (United States)

    2016-03-01

    significance of graduate education timing within the SWO community and its effect on retention and job performance. Job performance is measured as promotion...d. Marriage Marital status was used in previous studies of SWO retention and is included within this study (Abunaz & Tobrun, 2012). Three binary...the Navy or to separate such as demand for billets variation across years, private sector job opportunities. 44 Figure 5. Basic Retention Model

  16. Concept of Compound Retention Time for Organic Micro Pollutants in Anaerobic Membrane Bioreactor with Nanofiltration

    KAUST Repository

    Pan, Jiangjiang

    2011-01-01

    to control OMPs wastage. An innovative hybrid process, anaerobic membrane bioreactor with nanofiltration (AnMBR-NF), in which enhanced OMPs removal is possible based on the concept of compound retention time (CRT) through coupling anaerobic biodegradation

  17. DeepRT: deep learning for peptide retention time prediction in proteomics

    OpenAIRE

    Ma, Chunwei; Zhu, Zhiyong; Ye, Jun; Yang, Jiarui; Pei, Jianguo; Xu, Shaohang; Zhou, Ruo; Yu, Chang; Mo, Fan; Wen, Bo; Liu, Siqi

    2017-01-01

    Accurate predictions of peptide retention times (RT) in liquid chromatography have many applications in mass spectrometry-based proteomics. Herein, we present DeepRT, a deep learning based software for peptide retention time prediction. DeepRT automatically learns features directly from the peptide sequences using the deep convolutional Neural Network (CNN) and Recurrent Neural Network (RNN) model, which eliminates the need to use hand-crafted features or rules. After the feature learning, pr...

  18. Long-Term Retention in 3.5-Month-Olds: Familiarization Time and Individual Differences in Attentional Style.

    Science.gov (United States)

    Courage, Mary L.; Howe, Mark L.

    2001-01-01

    Examined effect of familiarization on 3.5-month-olds' retention of visual stimuli with varying delay times. Found support for retention models in which direction of attentional preferences (novel, familiar, or null) depends on memory accessibility. Short lookers showed better retention over time than long lookers, indicating that much of the…

  19. Optimal methods for fitting probability distributions to propagule retention time in studies of zoochorous dispersal.

    Science.gov (United States)

    Viana, Duarte S; Santamaría, Luis; Figuerola, Jordi

    2016-02-01

    Propagule retention time is a key factor in determining propagule dispersal distance and the shape of "seed shadows". Propagules dispersed by animal vectors are either ingested and retained in the gut until defecation or attached externally to the body until detachment. Retention time is a continuous variable, but it is commonly measured at discrete time points, according to pre-established sampling time-intervals. Although parametric continuous distributions have been widely fitted to these interval-censored data, the performance of different fitting methods has not been evaluated. To investigate the performance of five different fitting methods, we fitted parametric probability distributions to typical discretized retention-time data with known distribution using as data-points either the lower, mid or upper bounds of sampling intervals, as well as the cumulative distribution of observed values (using either maximum likelihood or non-linear least squares for parameter estimation); then compared the estimated and original distributions to assess the accuracy of each method. We also assessed the robustness of these methods to variations in the sampling procedure (sample size and length of sampling time-intervals). Fittings to the cumulative distribution performed better for all types of parametric distributions (lognormal, gamma and Weibull distributions) and were more robust to variations in sample size and sampling time-intervals. These estimated distributions had negligible deviations of up to 0.045 in cumulative probability of retention times (according to the Kolmogorov-Smirnov statistic) in relation to original distributions from which propagule retention time was simulated, supporting the overall accuracy of this fitting method. In contrast, fitting the sampling-interval bounds resulted in greater deviations that ranged from 0.058 to 0.273 in cumulative probability of retention times, which may introduce considerable biases in parameter estimates. We

  20. Determination of the retention time of feed in rumen using Sc-46 tracer

    International Nuclear Information System (INIS)

    Nadai, E.A. de; Castro, F.B. de; Barros Ferraz, E.S. de; Machado, P.F.; Nascimento Filho, V.F. do; Pessenda, L.C.R.; Sao Paulo Univ., Piracicaba

    1988-01-01

    The retention time of fibrous feed materials in rumen is of prime importance by providing parameters to evaluate its nutritional value. Some existing marker methods have been presenting serious problems such as physico-chemical alterations of feedstuff during the treatment and also marker migration in rumen conditions. In this study, the rare-earth element Scandium-46 has been applied to marking sugarcane bagasse physically processed. The data showed no significant migration of marker to liquid phase. The retention time in the rumen fistulated cow was 23.06 hours. Correlation coefficient of elapsed time after marking with logarithm of specific activity of ruminal content was 0.9986**. (author) [pt

  1. Hydraulic retention time on vinasse stabilisation with limestone in the acidogenic phase of anaerobic digestion

    Directory of Open Access Journals (Sweden)

    Ismael Plácido Tomielis

    Full Text Available ABSTRACT: The main problem in anaerobic digestion of low-protein residues is the instability caused acidity. The use of limestone at the same time as a neutralizing agent and support material is innovative because stones wear allows the slow release of the calcium carbonate thereby eliminating dispersers. Free calcium content in the system was measured in two plug flow reactors filled with vinasse at initial pH of 4.50. The proportion of 1.8 tonnes of limestone per m³ of vinasse was evaluated at the Hydraulic Retention Times (HRT of 24, 48, 72, 96 and 120 hours, allowing stabilisation at 96 hours. The ratio of Volatile Acids/Total Alkalinity (VA/TA ranged from 0.2 to 0.4 and the pH reached 7.0, at the HRT of 120 hours. Increasing the HRT also increased the volatile total solids (VTS and fixed total solids (TFS in a similar profile to the measured free calcium content, but calcium remained at the appropriate level of 100 to 250mg l-1. The proportion of limestone/vinasse was adequate to ensure stabilisation, but it is not recommended to reduce the HRT below 96 hours due to the risk of compromising the stability of the anaerobic system.

  2. Determination of the main retention time of feed in the digestive tract of sheep

    International Nuclear Information System (INIS)

    Geissler, C.; Dittrich, A.; Hoffmann, M.; Leistner, E.; Bier, H.; Militz, H.

    1985-01-01

    The medium retention time of the test feed in sheep was determined in ewes during three stages of the reproduction cycle. The feed was labelled with 51 Cr 2 O 3 . Experimental conditions are described on which the experiments can be carried out within the permissible limits. (author)

  3. Retention time variability as a mechanism for animal mediated long-distance dispersal.

    Directory of Open Access Journals (Sweden)

    Vishwesha Guttal

    Full Text Available Long-distance dispersal (LDD events, although rare for most plant species, can strongly influence population and community dynamics. Animals function as a key biotic vector of seeds and thus, a mechanistic and quantitative understanding of how individual animal behaviors scale to dispersal patterns at different spatial scales is a question of critical importance from both basic and applied perspectives. Using a diffusion-theory based analytical approach for a wide range of animal movement and seed transportation patterns, we show that the scale (a measure of local dispersal of the seed dispersal kernel increases with the organisms' rate of movement and mean seed retention time. We reveal that variations in seed retention time is a key determinant of various measures of LDD such as kurtosis (or shape of the kernel, thinkness of tails and the absolute number of seeds falling beyond a threshold distance. Using empirical data sets of frugivores, we illustrate the importance of variability in retention times for predicting the key disperser species that influence LDD. Our study makes testable predictions linking animal movement behaviors and gut retention times to dispersal patterns and, more generally, highlights the potential importance of animal behavioral variability for the LDD of seeds.

  4. Effect of temperature and hydraulic retention time on hydrogen producing granules: Homoacetogenesis and morphological characteristics

    International Nuclear Information System (INIS)

    Abreu, A. A.; Danko, A. S.; Alves, M. M.

    2009-01-01

    The effect of temperature and hydraulic retention time (HRT) on the homoacetogenesisi and on the morphological characteristics of hydrogen producing granules was investigated. Hydrogen was produced using an expanded granular sludge blanket (EGSB) reactor, fed with glucose and L-arabinose, under mesophilic (37 degree centigrade), thermophilic (55 degree centigrade), and hyper thermophilic (70 degree centigrade) conditions. (Author)

  5. Everyday Attention and Lecture Retention: The Effects of Time, Fidgeting, and Mind Wandering

    Directory of Open Access Journals (Sweden)

    James eFarley

    2013-09-01

    Full Text Available We have all had our thoughts wander from the immediate task at hand. The emerging embodied cognition literature emphasizes the role that the body plays in human thought, and raises the possibility that changes in attentional focus may be associated with changes in body behaviour. Recent research has found that when individuals view a lecture, mind wandering increases as a function of time. In the present study we asked whether this decline in attention during lecture viewing was associated with fidgeting. Participants were filmed while they watched a 40-minute lecture video, and at regular 5 minute intervals provided ratings of their attentiveness. Following the lecture, participant's memory for the material was assessed. Fidgeting behaviour was coded from video recordings of each session. Results indicated that attention to, and retention of, lecture material declined as a function of time on task. Critically, and as predicted, fidgeting also increased with time on task. We also found that the relation between fidgeting and retention was significant even when the role of attention was factored into the equation, suggesting that fidgeting makes a unique contribution to retention of lecture material over and above that contributed by an individual’s attention. We propose a novel non-attentional stress-based account of fidgeting and how this impacts retention for lecture material over and above changes in levels in mind wandering vis-a-vis changes in attention.

  6. Negative Impact of Employment on Engineering Student Time Management, Time to Degree, and Retention: Faculty, Administrator, and Staff Perspectives

    Science.gov (United States)

    Tyson, Will

    2012-01-01

    Interviews with faculty, administrators, staff, and students at four engineering programs reveal the role of undergraduate student employment on retention and timely degree completion among engineering students. Dueling narratives reveal how student approaches to earning an engineering degree differ greatly from faculty, administrator, and staff…

  7. Matrix diffusion: heavy-tailed residence time distributions and their influence on radionuclide retention

    International Nuclear Information System (INIS)

    Haggerty, R.

    2002-01-01

    Matrix diffusion in rocks is frequently assumed to be both Fickian and effectively homogeneous over space- and time-scales relevant to radionuclide retention. This paper discusses some cases of rocks where one or both of these assumptions may be invalid and what the consequences may be for modeling and performance assessment: a single pore diffusivity and matrix block size which is not representative of the diffusion process at all time- or space-scales, a scale-dependent diffusion rate coefficient which decreases with time- and space-scales, a retention capacity of host rocks that may be smaller than apparent in laboratory and field tests because all of the pore space is not accessible via diffusion over the performance assessment-scale transport time. (J.S.)

  8. Prediction of retention time in reversed-phase liquid chromatography as a tool for steroid identification

    International Nuclear Information System (INIS)

    Randazzo, Giuseppe Marco; Tonoli, David; Hambye, Stephanie; Guillarme, Davy; Jeanneret, Fabienne; Nurisso, Alessandra; Goracci, Laura; Boccard, Julien; Rudaz, Serge

    2016-01-01

    The untargeted profiling of steroids constitutes a growing research field because of their importance as biomarkers of endocrine disruption. New technologies in analytical chemistry, such as ultra high-pressure liquid chromatography coupled with mass spectrometry (MS), offer the possibility of a fast and sensitive analysis. Nevertheless, difficulties regarding steroid identification are encountered when considering isotopomeric steroids. Thus, the use of retention times is of great help for the unambiguous identification of steroids. In this context, starting from the linear solvent strength (LSS) theory, quantitative structure retention relationship (QSRR) models, based on a dataset composed of 91 endogenous steroids and VolSurf + descriptors combined with a new dedicated molecular fingerprint, were developed to predict retention times of steroid structures in any gradient mode conditions. Satisfactory performance was obtained during nested cross-validation with a predictive ability (Q"2) of 0.92. The generalisation ability of the model was further confirmed by an average error of 4.4% in external prediction. This allowed the list of candidates associated with identical monoisotopic masses to be strongly reduced, facilitating definitive steroid identification. - Highlights: • Difficulties regarding steroid identification are encountered when considering isotopomeric steroids. • Quantitative structure retention relationship (QSRR) models were developed from the linear solvent strength theory. • A dataset composed of 91 steroids and VolSurf + descriptors combined with a new dedicated molecular fingerprint, were used. • The list of candidates associated with identical monoisotopic masses was reduced, facilitating steroid identification.

  9. Prediction of retention time in reversed-phase liquid chromatography as a tool for steroid identification

    Energy Technology Data Exchange (ETDEWEB)

    Randazzo, Giuseppe Marco [School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva (Switzerland); Tonoli, David [School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva (Switzerland); Swiss Centre for Applied Human Toxicology (SCAHT), Universities of Basel and Geneva, Basel (Switzerland); Human Protein Sciences Department, University of Geneva, Geneva (Switzerland); Hambye, Stephanie; Guillarme, Davy [School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva (Switzerland); Jeanneret, Fabienne [School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva (Switzerland); Swiss Centre for Applied Human Toxicology (SCAHT), Universities of Basel and Geneva, Basel (Switzerland); Human Protein Sciences Department, University of Geneva, Geneva (Switzerland); Nurisso, Alessandra [School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva (Switzerland); Goracci, Laura [Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia (Italy); Boccard, Julien [School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva (Switzerland); Rudaz, Serge, E-mail: serge.rudaz@unige.ch [School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva (Switzerland); Swiss Centre for Applied Human Toxicology (SCAHT), Universities of Basel and Geneva, Basel (Switzerland)

    2016-04-15

    The untargeted profiling of steroids constitutes a growing research field because of their importance as biomarkers of endocrine disruption. New technologies in analytical chemistry, such as ultra high-pressure liquid chromatography coupled with mass spectrometry (MS), offer the possibility of a fast and sensitive analysis. Nevertheless, difficulties regarding steroid identification are encountered when considering isotopomeric steroids. Thus, the use of retention times is of great help for the unambiguous identification of steroids. In this context, starting from the linear solvent strength (LSS) theory, quantitative structure retention relationship (QSRR) models, based on a dataset composed of 91 endogenous steroids and VolSurf + descriptors combined with a new dedicated molecular fingerprint, were developed to predict retention times of steroid structures in any gradient mode conditions. Satisfactory performance was obtained during nested cross-validation with a predictive ability (Q{sup 2}) of 0.92. The generalisation ability of the model was further confirmed by an average error of 4.4% in external prediction. This allowed the list of candidates associated with identical monoisotopic masses to be strongly reduced, facilitating definitive steroid identification. - Highlights: • Difficulties regarding steroid identification are encountered when considering isotopomeric steroids. • Quantitative structure retention relationship (QSRR) models were developed from the linear solvent strength theory. • A dataset composed of 91 steroids and VolSurf + descriptors combined with a new dedicated molecular fingerprint, were used. • The list of candidates associated with identical monoisotopic masses was reduced, facilitating steroid identification.

  10. Retention time prediction in temperature-​programmed, comprehensive two-​dimensional gas chromatography: Modeling and error assessment

    NARCIS (Netherlands)

    Barcaru, A.; Anroedh-Sampat, A.; Janssen, H.-G.; Vivó-Truyols, G.

    2014-01-01

    In this paper we present a model relating exptl. factors (column lengths, diams. and thickness, modulation times, pressures and temp. programs) with retention times. Unfortunately, an anal. soln. to calc. the retention in temp. programmed GC×GC is impossible, making thus necessary to perform a

  11. Field Soil Water Retention of the Prototype Hanford Barrier and Its Variability with Space and Time

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. F.

    2015-08-14

    Engineered surface barriers are used to isolate underlying contaminants from water, plants, animals, and humans. To understand the flow processes within a barrier and the barrier’s ability to store and release water, the field hydraulic properties of the barrier need to be known. In situ measurement of soil hydraulic properties and their variation over time is challenging because most measurement methods are destructive. A multiyear test of the Prototype Hanford Barrier (PHB) has yielded in situ soil water content and pressure data for a nine-year period. The upper 2 m layer of the PHB is a silt loam. Within this layer, water content and water pressure were monitored at multiple depths at 12 water balance stations using a neutron probe and heat dissipation units. Valid monitoring data from 1995 to 2003 for 4 depths at 12 monitoring stations were used to determine the field water retention of the silt loam layer. The data covered a wide range of wetness, from near saturation to the permanent wilt point, and each retention curve contained 51 to 96 data points. The data were described well with the commonly used van Genuchten water retention model. It was found that the spatial variation of the saturated and residual water content and the pore size distribution parameter were relatively small, while that of the van Genuchten alpha was relatively large. The effects of spatial variability of the retention properties appeared to be larger than the combined effects of added 15% w/w pea gravel and plant roots on the properties. Neither of the primary hydrological processes nor time had a detectible effect on the water retention of the silt loam barrier.

  12. Thermodynamic-based retention time predictions of endogenous steroids in comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Silva, Aline C A; Ebrahimi-Najafadabi, Heshmatollah; McGinitie, Teague M; Casilli, Alessandro; Pereira, Henrique M G; Aquino Neto, Francisco R; Harynuk, James J

    2015-05-01

    This work evaluates the application of a thermodynamic model to comprehensive two-dimensional gas chromatography (GC × GC) coupled with time-of-flight mass spectrometry for anabolic agent investigation. Doping control deals with hundreds of drugs that are prohibited in sports. Drug discovery in biological matrices is a challenging task that requires powerful tools when one is faced with the rapidly changing designer drug landscape. In this work, a thermodynamic model developed for the prediction of both primary and secondary retention times in GC × GC has been applied to trimethylsilylated hydroxyl (O-TMS)- and methoxime-trimethylsilylated carbonyl (MO-TMS)-derivatized endogenous steroids. This model was previously demonstrated on a pneumatically modulated GC × GC system, and is applied for the first time to a thermally modulated GC × GC system. Preliminary one-dimensional experiments allowed the calculation of thermodynamic parameters (ΔH, ΔS, and ΔC p ) which were successfully applied for the prediction of the analytes' interactions with the stationary phases of both the first-dimension column and the second-dimension column. The model was able to predict both first-dimension and second-dimension retention times with high accuracy compared with the GC × GC experimental measurements. Maximum differences of -8.22 s in the first dimension and 0.4 s in the second dimension were encountered for the O-TMS derivatives of 11β-hydroxyandrosterone and 11-ketoetiocholanolone, respectively. For the MO-TMS derivatives, the largest discrepancies were from testosterone (9.65 ) for the first-dimension retention times and 11-keto-etiocholanolone (0.4 s) for the second-dimension retention times.

  13. Prediction of retention times in comprehensive two-dimensional gas chromatography using thermodynamic models.

    Science.gov (United States)

    McGinitie, Teague M; Harynuk, James J

    2012-09-14

    A method was developed to accurately predict both the primary and secondary retention times for a series of alkanes, ketones and alcohols in a flow-modulated GC×GC system. This was accomplished through the use of a three-parameter thermodynamic model where ΔH, ΔS, and ΔC(p) for an analyte's interaction with the stationary phases in both dimensions are known. Coupling this thermodynamic model with a time summation calculation it was possible to accurately predict both (1)t(r) and (2)t(r) for all analytes. The model was able to predict retention times regardless of the temperature ramp used, with an average error of only 0.64% for (1)t(r) and an average error of only 2.22% for (2)t(r). The model shows promise for the accurate prediction of retention times in GC×GC for a wide range of compounds and is able to utilize data collected from 1D experiments. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Mini Tensiometer-Time Domain Reflectometry Coil Probe for Measuring Soil Water Retention Properties

    DEFF Research Database (Denmark)

    Subedi, Shaphal; Kawamoto, Ken; Karunarathna, Anurudda Kumara

    2013-01-01

    Time domain reflectometry (TDR) is used widely for measuring soil-water content. New TDR coil probe technology facilitates the development of small, nondestructive probes for simultaneous measurement of soil-water content (θ) and soil-water potential (ψ). In this study we developed mini tensiomet...... between measured soil-water retention curves (ψ > –100 cm H2O) by the new T-TDR coil probes and independent measurements by the hanging water column method....

  15. Cross-Linked Fluorescent Supramolecular Nanoparticles as Finite Tattoo Pigments with Controllable Intradermal Retention Times.

    Science.gov (United States)

    Choi, Jin-Sil; Zhu, Yazhen; Li, Hongsheng; Peyda, Parham; Nguyen, Thuy Tien; Shen, Mo Yuan; Yang, Yang Michael; Zhu, Jingyi; Liu, Mei; Lee, Mandy M; Sun, Shih-Sheng; Yang, Yang; Yu, Hsiao-Hua; Chen, Kai; Chuang, Gary S; Tseng, Hsian-Rong

    2017-01-24

    Tattooing has been utilized by the medical community for precisely demarcating anatomic landmarks. This practice is especially important for identifying biopsy sites of nonmelanoma skin cancer (NMSC) due to the long interval (i.e., up to 3 months) between the initial diagnostic biopsy and surgical treatment. Commercially available tattoo pigments possess several issues, which include causing poor cosmesis, being mistaken for a melanocytic lesion, requiring additional removal procedures when no longer desired, and potentially inducing inflammatory responses. The ideal tattoo pigment for labeling of skin biopsy sites for NMSC requires (i) invisibility under ambient light, (ii) fluorescence under a selective light source, (iii) a finite intradermal retention time (ca. 3 months), and (iv) biocompatibility. Herein, we introduce cross-linked fluorescent supramolecular nanoparticles (c-FSNPs) as a "finite tattoo" pigment, with optimized photophysical properties and intradermal retention time to achieve successful in vivo finite tattooing. Fluorescent supramolecular nanoparticles encapsulate a fluorescent conjugated polymer, poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene] (MPS-PPV), into a core via a supramolecular synthetic approach. FSNPs which possess fluorescent properties superior to those of the free MPS-PPV are obtained through a combinatorial screening process. Covalent cross-linking of FSNPs results in micrometer-sized c-FSNPs, which exhibit a size-dependent intradermal retention. The 1456 nm sized c-FSNPs display an ideal intradermal retention time (ca. 3 months) for NMSC lesion labeling, as observed in an in vivo tattoo study. In addition, the c-FSNPs induce undetectable inflammatory responses after tattooing. We believe that the c-FSNPs can serve as a "finite tattoo" pigment to label potential malignant NMSC lesions.

  16. A simple method for HPLC retention time prediction: linear calibration using two reference substances.

    Science.gov (United States)

    Sun, Lei; Jin, Hong-Yu; Tian, Run-Tao; Wang, Ming-Juan; Liu, Li-Na; Ye, Liu-Ping; Zuo, Tian-Tian; Ma, Shuang-Cheng

    2017-01-01

    Analysis of related substances in pharmaceutical chemicals and multi-components in traditional Chinese medicines needs bulk of reference substances to identify the chromatographic peaks accurately. But the reference substances are costly. Thus, the relative retention (RR) method has been widely adopted in pharmacopoeias and literatures for characterizing HPLC behaviors of those reference substances unavailable. The problem is it is difficult to reproduce the RR on different columns due to the error between measured retention time (t R ) and predicted t R in some cases. Therefore, it is useful to develop an alternative and simple method for prediction of t R accurately. In the present study, based on the thermodynamic theory of HPLC, a method named linear calibration using two reference substances (LCTRS) was proposed. The method includes three steps, procedure of two points prediction, procedure of validation by multiple points regression and sequential matching. The t R of compounds on a HPLC column can be calculated by standard retention time and linear relationship. The method was validated in two medicines on 30 columns. It was demonstrated that, LCTRS method is simple, but more accurate and more robust on different HPLC columns than RR method. Hence quality standards using LCTRS method are easy to reproduce in different laboratories with lower cost of reference substances.

  17. Fast Mapping Across Time: Memory Processes Support Children's Retention of Learned Words

    Directory of Open Access Journals (Sweden)

    Haley eVlach

    2012-02-01

    Full Text Available Children's remarkable ability to map linguistic labels to objects in the world is referred to as fast mapping. The current study examined children's (N = 216 and adults’ (N = 54 retention of fast-mapped words over time (immediately, after a 1 week delay, and after a 1 month delay. The fast mapping literature often characterizes children's retention of words as consistently high across timescales. However, the current study demonstrates that learners forget word mappings at a rapid rate. Moreover, these patterns of forgetting parallel forgetting functions of domain general memory processes. Memory processes are critical to children's word learning and the role of one such process, forgetting, is discussed in detail—forgetting supports both word mapping and the generalization of words and categories.

  18. Fast Mapping Across Time: Memory Processes Support Children's Retention of Learned Words.

    Science.gov (United States)

    Vlach, Haley A; Sandhofer, Catherine M

    2012-01-01

    Children's remarkable ability to map linguistic labels to referents in the world is commonly called fast mapping. The current study examined children's (N = 216) and adults' (N = 54) retention of fast-mapped words over time (immediately, after a 1-week delay, and after a 1-month delay). The fast mapping literature often characterizes children's retention of words as consistently high across timescales. However, the current study demonstrates that learners forget word mappings at a rapid rate. Moreover, these patterns of forgetting parallel forgetting functions of domain-general memory processes. Memory processes are critical to children's word learning and the role of one such process, forgetting, is discussed in detail - forgetting supports extended mapping by promoting the memory and generalization of words and categories.

  19. Measurement of the Retention Time of Different Ophthalmic Formulations with Ultrahigh-Resolution Optical Coherence Tomography.

    Science.gov (United States)

    Gagliano, Caterina; Papa, Vincenzo; Amato, Roberta; Malaguarnera, Giulia; Avitabile, Teresio

    2018-04-01

    Purpose/aim of the study: The purpose of this study was to measure the pre-corneal retention time of two marketed formulations (eye drops and eye gel) of a steroid-antibiotic fixed combination (FC) containing 0.1% dexamethasone and 0.3% netilmicin. Pre-corneal retention time was evaluated in 16 healthy subjects using an ultrahigh-resolution anterior segment spectral domain optical coherence tomography (OCT). All subjects randomly received both formulations of the FC (Netildex, SIFI, Italy). Central tear film thickness (CTFT) was measured before instillation (time 0) and then after 1, 10, 20, 30, 40 50, 60 and 120 min. The pre-corneal retention time was calculated by plotting CTFT as a function of time. Differences between time points and groups were analyzed by Student's t-test. CTFT increased significantly after the instillation of the eye gel formulation (p < 0.001). CTFT reached its maximum value 1 min after instillation and returned to baseline after 60 min. No effect on CTFT was observed after the instillation of eye drops. The difference between the two formulations was statistically significant at time 1 min (p < 0.0001), 10 min (p < 0.001) and 20 min (p < 0.01). The FC formulated as eye gel was retained on the ocular surface longer than the corresponding eye drop solution. Consequently, the use of the eye gel might extend the interval between instillations and decrease the frequency of administration.

  20. Predicting Factors of Perceived Organizational Support by Full-Time and Part-Time Community College Faculty as Relates to Student Retention Rates

    Science.gov (United States)

    Nichols, Sarah K.

    2012-01-01

    Student retention is socially, politically, and financially important to educational institutions. This quantitative study explored the gap in research regarding the relationship between employment of part-time in lieu of full-time faculty and student retention. The campus climate exchange model (CCEM), served as the conceptual framework in this…

  1. Retention time generates short-term phytoplankton blooms in a shallow microtidal subtropical estuary

    Science.gov (United States)

    Odebrecht, Clarisse; Abreu, Paulo C.; Carstensen, Jacob

    2015-09-01

    In this study it was hypothesised that increasing water retention time promotes phytoplankton blooms in the shallow microtidal Patos Lagoon estuary (PLE). This hypothesis was tested using salinity variation as a proxy of water retention time and chlorophyll a for phytoplankton biomass. Submersible sensors fixed at 5 m depth near the mouth of PLE continuously measured water temperature, salinity and pigments fluorescence (calibrated to chlorophyll a) between March 2010 and 12th of December 2011, with some gaps. Salinity variations were used to separate alternating patterns of outflow of lagoon water (salinity 24; 35% of the time). The two transition phases represented a rapid change from lagoon water outflow to marine water inflow and a more gradually declining salinity between the dominating inflow and outflow conditions. During the latter of these, a significant chlorophyll a increase relative to that expected from a linear mixing relationship was observed at intermediate salinities (10-20). The increase in chlorophyll a was positively related to the duration of the prior coastal water inflow in the PLE. Moreover, chlorophyll a increase was significantly higher during austral spring-summer than autumn-winter, probably due to higher light and nutrient availability in the former. Moreover, the retention time process operating on time scales of days influences the long-term phytoplankton variability in this ecosystem. Comparing these results with monthly data from a nearby long-term water quality monitoring station (1993-2011) support the hypothesis that chlorophyll a accumulations occur after marine inflow events, whereas phytoplankton does not accumulate during high water outflow, when the water residence time is short. These results suggest that changing hydrological pattern is the most important mechanism underlying phytoplankton blooms in the PLE.

  2. Fission track retention in minerals as a function of heating time during isothermal experiments

    International Nuclear Information System (INIS)

    Burchart, J.; Butkiewicz, T.; Dakowski, M.; Galazka-Friedman, J.

    1979-01-01

    The linear dependence of track retention on logarithm of heating time (at constant temperature) has been verified by statistical analysis of data on isothermal annealing of apatite. The other functions proposed (rho/rho 0 as a linearly decreasing function of exp t or t) fit the experimental data only within a limited range of heating times, where the shapes of all three are experimentally hard to resolve. The logarithmic relationship implies a memory of tracks for thermal events and creates a basis for methods of age corrections. (author)

  3. A simple, fast, and accurate thermodynamic-based approach for transfer and prediction of gas chromatography retention times between columns and instruments Part III: Retention time prediction on target column.

    Science.gov (United States)

    Hou, Siyuan; Stevenson, Keisean A J M; Harynuk, James J

    2018-03-27

    This is the third part of a three-part series of papers. In Part I, we presented a method for determining the actual effective geometry of a reference column as well as the thermodynamic-based parameters of a set of probe compounds in an in-house mixture. Part II introduced an approach for estimating the actual effective geometry of a target column by collecting retention data of the same mixture of probe compounds on the target column and using their thermodynamic parameters, acquired on the reference column, as a bridge between both systems. Part III, presented here, demonstrates the retention time transfer and prediction from the reference column to the target column using experimental data for a separate mixture of compounds. To predict the retention time of a new compound, we first estimate its thermodynamic-based parameters on the reference column (using geometric parameters determined previously). The compound's retention time on a second column (of previously determined geometry) is then predicted. The models and the associated optimization algorithms were tested using simulated and experimental data. The accuracy of predicted retention times shows that the proposed approach is simple, fast, and accurate for retention time transfer and prediction between gas chromatography columns. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Uncertainty estimation of predictions of peptides' chromatographic retention times in shotgun proteomics.

    Science.gov (United States)

    Maboudi Afkham, Heydar; Qiu, Xuanbin; The, Matthew; Käll, Lukas

    2017-02-15

    Liquid chromatography is frequently used as a means to reduce the complexity of peptide-mixtures in shotgun proteomics. For such systems, the time when a peptide is released from a chromatography column and registered in the mass spectrometer is referred to as the peptide's retention time . Using heuristics or machine learning techniques, previous studies have demonstrated that it is possible to predict the retention time of a peptide from its amino acid sequence. In this paper, we are applying Gaussian Process Regression to the feature representation of a previously described predictor E lude . Using this framework, we demonstrate that it is possible to estimate the uncertainty of the prediction made by the model. Here we show how this uncertainty relates to the actual error of the prediction. In our experiments, we observe a strong correlation between the estimated uncertainty provided by Gaussian Process Regression and the actual prediction error. This relation provides us with new means for assessment of the predictions. We demonstrate how a subset of the peptides can be selected with lower prediction error compared to the whole set. We also demonstrate how such predicted standard deviations can be used for designing adaptive windowing strategies. lukas.kall@scilifelab.se. Our software and the data used in our experiments is publicly available and can be downloaded from https://github.com/statisticalbiotechnology/GPTime . © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

  5. Concept of Compound Retention Time for Organic Micro Pollutants in Anaerobic Membrane Bioreactor with Nanofiltration

    KAUST Repository

    Pan, Jiangjiang

    2011-12-01

    Organic micropollutants (OMPs) have received more and more attention in recent years due to their potential harmful effects on public health and aquatic ecosystems, and eliminating OMPs in wastewater treatment systems is an important solution to control OMPs wastage. An innovative hybrid process, anaerobic membrane bioreactor with nanofiltration (AnMBR-NF), in which enhanced OMPs removal is possible based on the concept of compound retention time (CRT) through coupling anaerobic biodegradation and NF rejection, is proposed and examined in terms of preliminary feasibility in this study. First, NF membrane screening through sludge water dead-end filtration tests demonstrated that KOCH NF200 (molecular weight cut-off (MWCO) 200 Da, acid/base stable) performed best in organic matter rejection. Then, selected OMPs (ketobrofen and naproxen) in MQ water and a biologically treated wastewater matrix were filtered through NF200 under constant-pressure dead-end mode, with and without stirring, and several methods (contact angle, scanning electronic microscopy, Zeta potential, Fourier transform infra-red spectroscopy) were used to characterize membranes. Results show selected OMPs in MQ could be rejected (about 40%) by a clean NF200 membrane. The main rejection mechanism was initial absorption by the membrane followed by size exclusion (electric charge interaction plays a less important role). The wastewater matrix could enhance the rejection significantly (up to 90%) because effluent organic matter (EfOM) enhanced size exclusion and electric charge interaction through blocking membrane pores and forming a gel layer as well as binding some OMPs through partitioning followed by retention by NF. Third, an anaerobic bioreactor was set up to evaluate the anaerobic biodegradability of selected OMPs. Results showed selected OMPs could be absorbed by sludge and reached equilibrium within one day, and then were consumed by anaerobic microorganism with a half life 9.4 days for

  6. An Interactionalist Analysis of Soldier Retention across Career Stages and Time

    National Research Council Canada - National Science Library

    Chen, Gilad; Ployhart, Robert E

    2006-01-01

    ...., work characteristics and social support), job attitudes, motivation, and retention. In general, it is proposed that job attitudes and motivation mediate the impact of ability and situational variables on retention outcomes...

  7. Lead pellet retention time and associated toxicity in northern bobwhite quail (Colinus virginianus).

    Science.gov (United States)

    Kerr, Richard; Holladay, Steven; Jarrett, Timothy; Selcer, Barbara; Meldrum, Blair; Williams, Susan; Tannenbaum, Lawrence; Holladay, Jeremy; Williams, Jamie; Gogal, Robert

    2010-12-01

    Birds are exposed to Pb by oral ingestion of spent Pb shot as grit. A paucity of data exists for retention and clearance of these particles in the bird gastrointestinal tract. In the current study, northern bobwhite quail (Colinus virginianus) were orally gavaged with 1, 5, or 10 Pb shot pellets, of 2-mm diameter, and radiographically followed over time. Blood Pb levels and other measures of toxicity were collected, to correlate with pellet retention. Quail dosed with either 5 or 10 pellets exhibited morbidity between weeks 1 and 2 and were removed from further study. Most of the Pb pellets were absorbed or excreted within 14 d of gavage, independent of dose. Pellet size in the ventriculus decreased over time in radiographs, suggesting dissolution caused by the acidic pH. Birds dosed with one pellet showed mean blood Pb levels that exceeded 1,300 µg/dl at week 1, further supporting dissolution in the gastrointestinal tract. Limited signs of toxicity were seen in the one-pellet birds; however, plasma δ-aminolevulinic acid dehydratase (d-ALAD) activity was persistently depressed, suggesting possible impaired hematological function. © 2010 SETAC.

  8. Waste activated sludge fermentation: effect of solids retention time and biomass concentration.

    Science.gov (United States)

    Yuan, Q; Sparling, R; Oleszkiewicz, J A

    2009-12-01

    Laboratory scale, room temperature, semi-continuous reactors were set-up to investigate the effect of solids retention time (SRT, equal to HRT hydraulic retention time) and biomass concentration on generation of volatile fatty acids (VFA) from the non-methanogenic fermentation of waste activated sludge (WAS) originating from an enhanced biological phosphorus removal process. It was found that VFA yields increased with SRT. At the longest SRT (10d), improved biomass degradation resulted in the highest soluble to total COD ratio and the highest VFA yield from the influent COD (0.14g VFA-COD/g TCOD). It was also observed that under the same SRT, VFA yields increased when the biomass concentration decreased. At a 10d SRT the VFA yield increased by 46%, when the biomass concentration decreased from 13g/L to 4.8g/L. Relatively high nutrient release was observed during fermentation. The average phosphorus release was 17.3mg PO(4)-P/g TCOD and nitrogen release was 25.8mg NH(4)-N/g TCOD.

  9. Similarity solutions of the Fokker–Planck equation with time-dependent coefficients

    International Nuclear Information System (INIS)

    Lin, W.-T.; Ho, C.-L.

    2012-01-01

    In this work, we consider the solvability of the Fokker–Planck equation with both time-dependent drift and diffusion coefficients by means of the similarity method. By the introduction of the similarity variable, the Fokker–Planck equation is reduced to an ordinary differential equation. Adopting the natural requirement that the probability current density vanishes at the boundary, the resulting ordinary differential equation turns out to be integrable, and the probability density function can be given in closed form. New examples of exactly solvable Fokker–Planck equations are presented, and their properties analyzed. - Highlights: ► Scaling form of the Fokker–Planck equation with time-dependent drift and diffusion coefficients is derived. ► Exact similarity solution of the Fokker–Planck equation is given in closed forms. ► New examples of Fokker–Planck equations exactly solvable by similarity methods are discussed.

  10. Dynamic Time Warping Distance Method for Similarity Test of Multipoint Ground Motion Field

    Directory of Open Access Journals (Sweden)

    Yingmin Li

    2010-01-01

    Full Text Available The reasonability of artificial multi-point ground motions and the identification of abnormal records in seismic array observations, are two important issues in application and analysis of multi-point ground motion fields. Based on the dynamic time warping (DTW distance method, this paper discusses the application of similarity measurement in the similarity analysis of simulated multi-point ground motions and the actual seismic array records. Analysis results show that the DTW distance method not only can quantitatively reflect the similarity of simulated ground motion field, but also offers advantages in clustering analysis and singularity recognition of actual multi-point ground motion field.

  11. Models for discrete-time self-similar vector processes with application to network traffic

    Science.gov (United States)

    Lee, Seungsin; Rao, Raghuveer M.; Narasimha, Rajesh

    2003-07-01

    The paper defines self-similarity for vector processes by employing the discrete-time continuous-dilation operation which has successfully been used previously by the authors to define 1-D discrete-time stochastic self-similar processes. To define self-similarity of vector processes, it is required to consider the cross-correlation functions between different 1-D processes as well as the autocorrelation function of each constituent 1-D process in it. System models to synthesize self-similar vector processes are constructed based on the definition. With these systems, it is possible to generate self-similar vector processes from white noise inputs. An important aspect of the proposed models is that they can be used to synthesize various types of self-similar vector processes by choosing proper parameters. Additionally, the paper presents evidence of vector self-similarity in two-channel wireless LAN data and applies the aforementioned systems to simulate the corresponding network traffic traces.

  12. Effects of oxidation potential and retention time on electrochromic stability of poly (3-hexyl thiophene) films

    Science.gov (United States)

    Kim, Tae-Ho; Hyun Song, Seok; Kim, Hyo-Jae; Oh, Seong-Hyeon; Han, Song-Yi; Kim, Goung; Nah, Yoon-Chae

    2018-06-01

    Herein, we report the effects of applied voltage on the electrochromic (EC) stability of poly(3-hexylthiophene) (P3HT) films during EC reactions. The transmittance difference and cycling stability of these films were monitored to optimize the oxidation voltage, and their chemical compositions were analyzed by X-ray photoelectron spectroscopy after long-term electrochemical cycling. High oxidation voltages increased the color contrast of P3HT films but decreased their cycling stability due to facilitating chemical degradation. Furthermore, at an optimized oxidation voltage, the retention time during potential pulsing was adjusted utilizing the optical memory of P3HT, revealing that the decreased voltage application time reduced power consumption by 9.6% and enhanced EC stability without loss of color contrast.

  13. Prediction of the human response time with the similarity and quantity of information

    International Nuclear Information System (INIS)

    Lee, Sungjin; Heo, Gyunyoung; Chang, Soon Heung

    2006-01-01

    Memory is one of brain processes that are important when trying to understand how people process information. Although a large number of studies have been made on the human performance, little is known about the similarity effect in human performance. The purpose of this paper is to propose and validate the quantitative and predictive model on the human response time in the user interface with the concept of similarity. However, it is not easy to explain the human performance with only similarity or information amount. We are confronted by two difficulties: making the quantitative model on the human response time with the similarity and validating the proposed model by experimental work. We made the quantitative model based on the Hick's law and the law of practice. In addition, we validated the model with various experimental conditions by measuring participants' response time in the environment of computer-based display. Experimental results reveal that the human performance is improved by the user interface's similarity. We think that the proposed model is useful for the user interface design and evaluation phases

  14. The predictive model on the user reaction time using the information similarity

    International Nuclear Information System (INIS)

    Lee, Sung Jin; Heo, Gyun Young; Chang, Soon Heung

    2005-01-01

    Human performance is frequently degraded because people forget. Memory is one of brain processes that are important when trying to understand how people process information. Although a large number of studies have been made on the human performance, little is known about the similarity effect in human performance. The purpose of this paper is to propose and validate the quantitative and predictive model on the human response time in the user interface with the concept of similarity. However, it is not easy to explain the human performance with only similarity or information amount. We are confronted by two difficulties: making the quantitative model on the human response time with the similarity and validating the proposed model by experimental work. We made the quantitative model based on the Hick's law and the law of practice. In addition, we validated the model with various experimental conditions by measuring participants' response time in the environment of computer-based display. Experimental results reveal that the human performance is improved by the user interface's similarity. We think that the proposed model is useful for the user interface design and evaluation phases

  15. Real-life 10-year retention rate of first-line anti-TNF drugs for inflammatory arthritides in adult- and juvenile-onset populations: similarities and differences.

    Science.gov (United States)

    Favalli, Ennio Giulio; Pontikaki, Irene; Becciolini, Andrea; Biggioggero, Martina; Ughi, Nicola; Romano, Micol; Crotti, Chiara; Gattinara, Maurizio; Gerloni, Valeria; Marchesoni, Antonio; Meroni, Pier Luigi

    2017-08-01

    The aim of this study is to retrospectively analyze 10-year drug survival of first-line TNF inhibitor (TNFi) in rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic arthritis (PsA), and juvenile idiopathic arthritis (JIA) patients, comparing withdrawal rates and discontinuation pattern between adult- and juvenile-onset populations. RA, AS, PsA, and JIA patients treated with infliximab, etanercept, or adalimumab as first TNFi between 1999 and 2015 were extracted from a local registry. Drug survival up to 10-year follow-up was evaluated by the Kaplan-Meier method and compared according to age (adult vs juvenile onset), TNFi agent, and discontinuation reason by a stratified log-rank test. Three hundred sixty JIA (205 etanercept, 66 adalimumab, and 89 infliximab) and 951 (607 RA, 188 AS, and 156 PsA) adult patients (464 infliximab, 262 adalimumab, and 225 etanercept) were included. After exclusion of systemic-onset JIA (18.5%), overall 10-year retention rate was 31.8%, with no difference between adult- and juvenile-onset patients (32.1 and 30.2%, respectively; HR 0.938 [95% CI 0.782-1.125]). Etanercept showed the highest drug survival in adult-onset population (p adult population (29.75%) with a significantly higher risk of discontinuation than in juvenile-onset subgroup (HR 1.390 [95% CI 1.060-1.824]). Serious infections and malignancies caused TNFi withdrawal only in adult whereas gastrointestinal, neuropsychiatric, and ocular complications quite only in juvenile patients. Despite a similar 10-year drug survival, adult- and juvenile-onset subpopulations showed a significantly different pattern of TNFi reasons for discontinuation.

  16. Are the correlates of sport participation similar to those of screen time?

    Directory of Open Access Journals (Sweden)

    Mark S. Allen

    2015-01-01

    Conclusion: Our findings show that demographic, socioeconomic and environmental factors measured at age 4 predict sport participation and screen time at age 12, and that the correlates of childhood sport participation and childhood sedentary behavior may be more similar than previously estimated.

  17. Collapsing perfect fluid in self-similar five dimensional space-time and cosmic censorship

    International Nuclear Information System (INIS)

    Ghosh, S.G.; Sarwe, S.B.; Saraykar, R.V.

    2002-01-01

    We investigate the occurrence and nature of naked singularities in the gravitational collapse of a self-similar adiabatic perfect fluid in a five dimensional space-time. The naked singularities are found to be gravitationally strong in the sense of Tipler and thus violate the cosmic censorship conjecture

  18. Gait Patterns in Twins with Cerebral Palsy: Similarities and Development over Time after Multilevel Surgery

    Science.gov (United States)

    van Drongelen, Stefan; Dreher, Thomas; Heitzmann, Daniel W. W.; Wolf, Sebastian I.

    2013-01-01

    To examine gait patterns and gait quality, 7 twins with cerebral palsy were measured preoperatively and after surgical intervention. The aim was to study differences and/or similarities in gait between twins, the influence of personal characteristics and birth conditions, and to describe the development of gait over time after single event…

  19. Retention of Basic Life Support in Laypeople: Mastery Learning vs. Time-based Education.

    Science.gov (United States)

    Boet, Sylvain; Bould, M Dylan; Pigford, Ashlee-Ann; Rössler, Bernhard; Nambyiah, Pratheeban; Li, Qi; Bunting, Alexandra; Schebesta, Karl

    2017-01-01

    To compare the effectiveness of a mastery learning (ML) versus a time-based (TB) BLS course for the acquisition and retention of BLS knowledge and skills in laypeople. After ethics approval, laypeople were randomized to a ML or TB BLS course based on the American Heart Association (AHA) Heartsaver course. In the ML group, subjects practiced and received feedback at six BLS stations until they reached a pre-determined level of performance. The TB group received a standard AHA six-station BLS course. All participants took the standard in-course BLS skills test at the end of their course. BLS skills and knowledge were tested using a high-fidelity scenario and knowledge questionnaire upon course completion (immediate post-test) and after four months (retention test). Video recorded scenarios were assessed by two blinded, independent raters using the AHA skills checklist. Forty-three subjects were included in analysis (23ML;20TB). For primary outcome, subjects' performance did not change after four months, regardless of the teaching modality (TB from (median[IQR]) 8.0[6.125;8.375] to 8.5[5.625;9.0] vs. ML from 8.0[7.0;9.0] to 7.0[6.0;8.0], p = 0.12 for test phase, p = 0.21 for interaction between effect of teaching modality and test phase). For secondary outcomes, subjects acquired knowledge between pre- and immediate post-tests (p < 0.005), and partially retained the acquired knowledge up to four months (p < 0.005) despite a decrease between immediate post-test and retention test (p = 0.009), irrespectively of the group (p = 0.59) (TB from 63.3[48.3;73.3] to 93.3[81.7;100.0] and then 93.3[81.7;93.3] vs. ML from 60.0[46.7;66.7] to 93.3[80.0;100.0] and then 80.0[73.3;93.3]). Regardless of the group after 4 months, chest compression depth improved (TB from 39.0[35.0;46.0] to 48.5[40.25;58.0] vs. ML from 40.0[37.0;47.0] to 45.0[37.0;52.0]; p = 0.012), but not the rate (TB from 118.0[114.0;125.0] to 120.5[113.0;129.5] vs. ML from 119.0[113.0;130.0] to 123.0[102.0;132.0]; p

  20. On the nature and impact of self-similarity in real-time systems

    OpenAIRE

    Enrique Hernández-Orallo; Vila Carbó, Juan Antonio

    2012-01-01

    In real-time systems with highly variable task execution times simplistic task models are insufficient to accurately model and to analyze the system. Variability can be tackled using distributions rather than a single value, but the proper charac- terization depends on the degree of variability. Self-similarity is one of the deep- est kinds of variability. It characterizes the fact that a workload is not only highly variable, but it is also bursty on many time-scales. This paper identifies in...

  1. Carbamazepine behaviour and effects in an urban wastewater MBR working with high sludge and hydraulic retention time.

    Science.gov (United States)

    González-Pérez, Daniel María; Pérez, Jorge Ignacio; Nieto, Miguel Ángel Gómez

    2016-08-23

    The behaviour and fate of carbamazepine (CBZ) in urban wastewater treatment by a membrane bioreactor (MBR) and its possible effects on the system's efficiency, and on mixed microbial communities, has been studied. The experimental microfiltration MBR system, with capacity to treat 10.8 m(3) d(-1) of urban wastewater, operated with a pre-denitrification configuration with high sludge and hydraulic retention time. The CBZ concentration assayed was higher than in the usual urban wastewater, in order to provoke a strong biomass reaction. Influent, effluent, and all bioreactors of the MBR system were analysed in order to calculate a CBZ balance. Bench-scale experiments and respirometric analyses were performed, with and without the presence of CBZ, to evaluate its influence on the bacterial activity. The respirometric assays showed variations in the oxygen uptake rate (OUR) in the presence of CBZ. Negative effects were detected in the MBR bacterial community during the initial period of dosing. However, the effects were not permanent and the biomass spiked with CBZ had behaviour similar to that of the biomass without CBZ after a few hours. Biodegradation was not detected during the MBR treatment. The system showed an inefficient elimination of CBZ (less than 10%) with a high concentration in the effluent. The small percentage of CBZ removal was associated with the sludge retention and eliminated by the purge. All CBZ present in the influent was accounted for, and even an increase in the total amount of CBZ was registered in the permeate. During and after the experimental process, CBZ did not significantly affect the efficiency of the MBR system, and the quality of the effluent was not affected by the dosing of CBZ in terms of COD and nitrogen removal.

  2. A standardized method for the calibration of thermodynamic data for the prediction of gas chromatographic retention times.

    Science.gov (United States)

    McGinitie, Teague M; Ebrahimi-Najafabadi, Heshmatollah; Harynuk, James J

    2014-02-21

    A new method for calibrating thermodynamic data to be used in the prediction of analyte retention times is presented. The method allows thermodynamic data collected on one column to be used in making predictions across columns of the same stationary phase but with varying geometries. This calibration is essential as slight variances in the column inner diameter and stationary phase film thickness between columns or as a column ages will adversely affect the accuracy of predictions. The calibration technique uses a Grob standard mixture along with a Nelder-Mead simplex algorithm and a previously developed model of GC retention times based on a three-parameter thermodynamic model to estimate both inner diameter and stationary phase film thickness. The calibration method is highly successful with the predicted retention times for a set of alkanes, ketones and alcohols having an average error of 1.6s across three columns. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Scaling relation between earthquake magnitude and the departure time from P wave similar growth

    Science.gov (United States)

    Noda, Shunta; Ellsworth, William L.

    2016-01-01

    We introduce a new scaling relation between earthquake magnitude (M) and a characteristic of initial P wave displacement. By examining Japanese K-NET data averaged in bins partitioned by Mw and hypocentral distance, we demonstrate that the P wave displacement briefly displays similar growth at the onset of rupture and that the departure time (Tdp), which is defined as the time of departure from similarity of the absolute displacement after applying a band-pass filter, correlates with the final M in a range of 4.5 ≤ Mw ≤ 7. The scaling relation between Mw and Tdp implies that useful information on the final M can be derived while the event is still in progress because Tdp occurs before the completion of rupture. We conclude that the scaling relation is important not only for earthquake early warning but also for the source physics of earthquakes.

  4. Similarity solutions of time-dependent relativistic radiation-hydrodynamical plane-parallel flows

    Science.gov (United States)

    Fukue, Jun

    2018-04-01

    Similarity solutions are examined for the frequency-integrated relativistic radiation-hydrodynamical flows, which are described by the comoving quantities. The flows are vertical plane-parallel time-dependent ones with a gray opacity coefficient. For adequate boundary conditions, the flows are accelerated in a somewhat homologous manner, but terminate at some singular locus, which originates from the pathological behavior in relativistic radiation moment equations truncated in finite orders.

  5. Prediction of gas chromatography/electron capture detector retention times of chlorinated pesticides, herbicides, and organohalides by multivariate chemometrics methods

    International Nuclear Information System (INIS)

    Ghasemi, Jahanbakhsh; Asadpour, Saeid; Abdolmaleki, Azizeh

    2007-01-01

    A quantitative structure-retention relationship (QSRR) study, has been carried out on the gas chromatograph/electron capture detector (GC/ECD) system retention times (t R s) of 38 diverse chlorinated pesticides, herbicides, and organohalides by using molecular structural descriptors. Modeling of retention times of these compounds as a function of the theoretically derived descriptors was established by multiple linear regression (MLR) and partial least squares (PLS) regression. The stepwise regression using SPSS was used for the selection of the variables that resulted in the best-fitted models. Appropriate models with low standard errors and high correlation coefficients were obtained. Three types of molecular descriptors including electronic, steric and thermodynamic were used to develop a quantitative relationship between the retention times and structural properties. MLR and PLS analysis has been carried out to derive the best QSRR models. After variables selection, MLR and PLS methods used with leave-one-out cross validation for building the regression models. The predictive quality of the QSRR models were tested for an external prediction set of 12 compounds randomly chosen from 38 compounds. The PLS regression method was used to model the structure-retention relationships, more accurately. However, the results surprisingly showed more or less the same quality for MLR and PLS modeling according to squared regression coefficients R 2 which were 0.951 and 0.948 for MLR and PLS, respectively

  6. Investigation of Time Series Representations and Similarity Measures for Structural Damage Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Wenjia Liu

    2013-01-01

    Full Text Available This paper investigates the time series representation methods and similarity measures for sensor data feature extraction and structural damage pattern recognition. Both model-based time series representation and dimensionality reduction methods are studied to compare the effectiveness of feature extraction for damage pattern recognition. The evaluation of feature extraction methods is performed by examining the separation of feature vectors among different damage patterns and the pattern recognition success rate. In addition, the impact of similarity measures on the pattern recognition success rate and the metrics for damage localization are also investigated. The test data used in this study are from the System Identification to Monitor Civil Engineering Structures (SIMCES Z24 Bridge damage detection tests, a rigorous instrumentation campaign that recorded the dynamic performance of a concrete box-girder bridge under progressively increasing damage scenarios. A number of progressive damage test case datasets and damage test data with different damage modalities are used. The simulation results show that both time series representation methods and similarity measures have significant impact on the pattern recognition success rate.

  7. Investigation of Time Series Representations and Similarity Measures for Structural Damage Pattern Recognition

    Science.gov (United States)

    Swartz, R. Andrew

    2013-01-01

    This paper investigates the time series representation methods and similarity measures for sensor data feature extraction and structural damage pattern recognition. Both model-based time series representation and dimensionality reduction methods are studied to compare the effectiveness of feature extraction for damage pattern recognition. The evaluation of feature extraction methods is performed by examining the separation of feature vectors among different damage patterns and the pattern recognition success rate. In addition, the impact of similarity measures on the pattern recognition success rate and the metrics for damage localization are also investigated. The test data used in this study are from the System Identification to Monitor Civil Engineering Structures (SIMCES) Z24 Bridge damage detection tests, a rigorous instrumentation campaign that recorded the dynamic performance of a concrete box-girder bridge under progressively increasing damage scenarios. A number of progressive damage test case datasets and damage test data with different damage modalities are used. The simulation results show that both time series representation methods and similarity measures have significant impact on the pattern recognition success rate. PMID:24191136

  8. Similarity-Based Prediction of Travel Times for Vehicles Traveling on Known Routes

    DEFF Research Database (Denmark)

    Tiesyte, Dalia; Jensen, Christian Søndergaard

    2008-01-01

    , historical data in combination with real-time data may be used to predict the future travel times of vehicles more accurately, thus improving the experience of the users who rely on such information. We propose a Nearest-Neighbor Trajectory (NNT) technique that identifies the historical trajectory......The use of centralized, real-time position tracking is proliferating in the areas of logistics and public transportation. Real-time positions can be used to provide up-to-date information to a variety of users, and they can also be accumulated for uses in subsequent data analyses. In particular...... of vehicles that travel along known routes. In empirical studies with real data from buses, we evaluate how well the proposed distance functions are capable of predicting future vehicle movements. Second, we propose a main-memory index structure that enables incremental similarity search and that is capable...

  9. Time, number and length: similarities and differences in discrimination in adults and children.

    Science.gov (United States)

    Droit-Volet, Sylvie; Clément, Angélique; Fayol, Michel

    2008-01-01

    The aim of this study was to focus on similarities in the discrimination of three different quantities--time, number, and line length--using a bisection task involving children aged 5 and 8 years and adults, when number and length were presented nonsequentially (Experiment 1) and sequentially (Experiment 2). In the nonsequential condition, for all age groups, although to a greater extent in the younger children, the psychophysical functions were flatter, and the Weber ratio higher for time than for number and length. Number and length yielded similar psychophysical functions. Thus, sensitivity to time was lower than that to the other quantities, whether continuous or not. However, when number and length were presented sequentially (Experiment 2), the differences in discrimination performance between time, number, and length disappeared. Furthermore, the Weber ratio values as well as the bisection points for all quantities presented sequentially appeared to be close to that found for duration in the nonsequential condition. The results are discussed within the framework of recent theories suggesting a common mechanism for all analogical quantities.

  10. Effect of hydraulic retention time on metal precipitation in sulfate reducing inverse fluidized bed reactors

    KAUST Repository

    Villa-Gómez, Denys Kristalia

    2014-02-13

    BACKGROUND: Metal sulfide recovery in sulfate reducing bioreactors is a challenge due to the formation of small precipitates with poor settling properties. The size of the metal sulfide precipitates with the change in operational parameters such as pH, sulfide concentration and reactor configuration has been previously studied. The effect of the hydraulic retention time (HRT) on the metal precipitate characteristics such as particle size for settling has not yet been addressed. RESULTS: The change in size of the metal (Cu, Zn, Pb and Cd) sulfide precipitates as a function of the HRT was studied in two sulfate reducing inversed fluidized bed (IFB) reactors operating at different chemical oxygen demand concentrations to produce high and low sulfide concentrations. The decrease of the HRT from 24 to 9h in both IFB reactors affected the contact time of the precipitates formed, thus making differences in aggregation and particle growth regardless of the differences in sulfide concentration. Further HRT decrease to 4.5h affected the sulfate reducing activity for sulfide production and hence, the supersaturation level and solid phase speciation. Metal sulfide precipitates affected the sulfate reducing activity and community in the biofilm, probably because of the stronger local supersaturation causing metal sulfides accumulation in the biofilm. CONCLUSIONS: This study shows that the HRT is an important factor determining the size and thus the settling rate of the metal sulfides formed in bioreactors.

  11. Kinetic modeling of the effect of solids retention time on methanethiol dynamics in anaerobic digestion.

    Science.gov (United States)

    Zhang, Dian; Strawn, Mary; Novak, John T; Wang, Zhi-Wu

    2018-07-01

    The highly volatile methanethiol (MT) with an extremely low odor threshold and distinctive putrid smell is often identified as a major odorous compound generated under anaerobic conditions. As an intermediate compound in the course of anaerobic digestion, the extent of MT emission is closely related to the time of anaerobic reaction. In this study, lab-scale anaerobic digesters were operated at solids retention time (SRTs) of 15, 20, 25, 30, 40 and 50 days to investigate the effect of SRT on MT emission. The experimental results demonstrated a bell-shaped curve of MT emission versus SRT with a peak around 20 days SRT. In order to understand this SRT effect, a kinetic model was developed to describe MT production and utilization dynamics in the course of anaerobic digestion and calibrated with the experimental results collected from this study. The model outcome revealed that the high protein content in the feed sludge together with the large maintenance coefficient of MT fermenters are responsible for the peak MT emission emergence in the range of typical SRT used for anaerobic digestion. A further analysis of the kinetic model shows that it can be extensively simplified with reasonable approximation to a form that anaerobic digestion practitioners could easily use to predict the MT and SRT relationship. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Timing of revenue streams from newly recruited faculty: implications for faculty retention.

    Science.gov (United States)

    Joiner, Keith A; Hiteman, Sarah; Wormsley, Steven; St Germain, Patricia

    2007-12-01

    To determine the timing and magnitude of revenues generated by newly recruited faculty, to facilitate configuration of recruitment packages appropriately matched to expected financial returns. The aggregate of all positive cash flows to central college of medicine administration -- from research, clinical care, tuition, philanthropy, and royalties and patents, from all faculty newly recruited to the University of Arizona College of Medicine between 1998 and 2004 -- was quantified using the net present value (npv) methodology, which incorporates the time value of money. Tenure-track faculty and, in particular, those with laboratory research programs, generated the highest positive central cash flows. The npv for positive cash flows (npv[+]) during 6 and 10 years for newly recruited assistant professors with laboratory research programs were $118,600 and $255,400, respectively, and, for professors with laboratory research programs, $172,600 and $298,000, respectively (associate professors were not analyzed because of limited numbers). Faculty whose appointments at the University of Arizona College of Medicine exceeded 15 years in duration were the most productive in central revenue generation, far in excess of their numbers proportionate to the total. The results emphasize the critical importance of faculty retention, because even those newly recruited faculty who are most successful in central revenue generation (tenure track with laboratory research programs) must be retained for periods well in excess of 10 years to recoup the initial central investment required for their recruitment.

  13. Sequence-Specific Model for Peptide Retention Time Prediction in Strong Cation Exchange Chromatography.

    Science.gov (United States)

    Gussakovsky, Daniel; Neustaeter, Haley; Spicer, Victor; Krokhin, Oleg V

    2017-11-07

    The development of a peptide retention prediction model for strong cation exchange (SCX) separation on a Polysulfoethyl A column is reported. Off-line 2D LC-MS/MS analysis (SCX-RPLC) of S. cerevisiae whole cell lysate was used to generate a retention dataset of ∼30 000 peptides, sufficient for identifying the major sequence-specific features of peptide retention mechanisms in SCX. In contrast to RPLC/hydrophilic interaction liquid chromatography (HILIC) separation modes, where retention is driven by hydrophobic/hydrophilic contributions of all individual residues, SCX interactions depend mainly on peptide charge (number of basic residues at acidic pH) and size. An additive model (incorporating the contributions of all 20 residues into the peptide retention) combined with a peptide length correction produces a 0.976 R 2 value prediction accuracy, significantly higher than the additive models for either HILIC or RPLC. Position-dependent effects on peptide retention for different residues were driven by the spatial orientation of tryptic peptides upon interaction with the negatively charged surface functional groups. The positively charged N-termini serve as a primary point of interaction. For example, basic residues (Arg, His, Lys) increase peptide retention when located closer to the N-terminus. We also found that hydrophobic interactions, which could lead to a mixed-mode separation mechanism, are largely suppressed at 20-30% of acetonitrile in the eluent. The accuracy of the final Sequence-Specific Retention Calculator (SSRCalc) SCX model (∼0.99 R 2 value) exceeds all previously reported predictors for peptide LC separations. This also provides a solid platform for method development in 2D LC-MS protocols in proteomics and peptide retention prediction filtering of false positive identifications.

  14. Improvement of training set structure in fusion data cleaning using Time-Domain Global Similarity method

    International Nuclear Information System (INIS)

    Liu, J.; Lan, T.; Qin, H.

    2017-01-01

    Traditional data cleaning identifies dirty data by classifying original data sequences, which is a class-imbalanced problem since the proportion of incorrect data is much less than the proportion of correct ones for most diagnostic systems in Magnetic Confinement Fusion (MCF) devices. When using machine learning algorithms to classify diagnostic data based on class-imbalanced training set, most classifiers are biased towards the major class and show very poor classification rates on the minor class. By transforming the direct classification problem about original data sequences into a classification problem about the physical similarity between data sequences, the class-balanced effect of Time-Domain Global Similarity (TDGS) method on training set structure is investigated in this paper. Meanwhile, the impact of improved training set structure on data cleaning performance of TDGS method is demonstrated with an application example in EAST POlarimetry-INTerferometry (POINT) system.

  15. A Framework for Similarity Search with Space-Time Tradeoffs using Locality Sensitive Filtering

    DEFF Research Database (Denmark)

    Christiani, Tobias Lybecker

    2017-01-01

    that satisfies certain locality-sensitivity properties, we can construct a dynamic data structure that solves the approximate near neighbor problem in $d$-dimensional space with query time $dn^{\\rho_q + o(1)}$, update time $dn^{\\rho_u + o(1)}$, and space usage $dn + n^{1 + \\rho_u + o(1)}$ where $n$ denotes......We present a framework for similarity search based on Locality-Sensitive Filtering~(LSF),generalizing the Indyk-Motwani (STOC 1998) Locality-Sensitive Hashing~(LSH) framework to support space-time tradeoffs. Given a family of filters, defined as a distribution over pairs of subsets of space...... the number of points in the data structure.The space-time tradeoff is tied to the tradeoff between query time and update time (insertions/deletions), controlled by the exponents $\\rho_q, \\rho_u$ that are determined by the filter family. \\\\ Locality-sensitive filtering was introduced by Becker et al. (SODA...

  16. The Influence of a Career Exploration Course on New First-Time Student Retention at a Public Midwest Community College

    Science.gov (United States)

    French, Brenda F.

    2013-01-01

    The purpose of this study was to examine whether a relationship exists between new first- time students enrolled in a career exploration course and retention during the academic years of 2009 to 2011 at a public Midwest community college. Change of major after the first semester was also investigated. The study utilized quantitative, archival data…

  17. Effect of solids retention time on the bioavailability of organic carbon in anaerobically digested swine waste.

    Science.gov (United States)

    Kinyua, Maureen N; Cunningham, Jeffrey; Ergas, Sarina J

    2014-06-01

    Anaerobic digestion (AD) can be used to stabilize and produce energy from livestock waste; however, digester effluents may require further treatment to remove nitrogen. This paper quantifies the effects of varying solids retention time (SRT) methane yield, volatile solids (VS) reduction and organic carbon bioavailability for denitrification during swine waste AD. Four bench-scale anaerobic digesters, with SRTs of 14, 21, 28 and 42 days, operated with swine waste feed. Effluent organic carbon bioavailability was measured using anoxic microcosms and respirometry. Excellent performance was observed for all four digesters, with >60% VS removal and CH4 yields between 0.1 and 0.3(m(3)CH4)/(kg VS added). Organic carbon in the centrate as an internal organic carbon source for denitrification supported maximum specific denitrification rates between 47 and 56(mg NO3(-)-N)/(g VSS h). The digester with the 21-day SRT had the highest CH4 yield and maximum specific denitrification rates. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Characteristics and fates of soluble microbial products in ceramic membrane bioreactor at various sludge retention times.

    Science.gov (United States)

    Shin, Hang-Sik; Kang, Seok-Tae

    2003-01-01

    The formation and fate of soluble microbial products (SMP) in membrane bioreactor (MBR) was investigated at various sludge retention times (SRT) for 170 days. The SMP concentration was estimated by feeding glucose, which could be completely degraded, and by measuring the dissolved organic carbon (DOC) of the effluent from MBR. Under the conditions of SRT of 20 days, influent DOC of 112 mg/l and HRT of 6 h, the produced SMP was 4.7 mg DOC/l of which 57% was removed or retained by the membrane. DOC of MBR supernatant increased during 100 days and then gradually decreased. Specific UV absorbance showed that the accumulated compounds had a portion of larger, more aromatic, more hydrophobic and double-bond-rich organics, which originated from the decayed biomass. Molecular weight distributions of SMP in MBR supernatant showed that the acclimated microorganisms in a long SRT could decompose high molecular weight organics, it caused the shift of molecular weight distributions of SMP to a lower range. During the operation period, enumeration of active cells in the MBR showed that microbial inhibitions by accumulated SMP was not observed.

  19. Influence of hydraulic retention time on UASB post-treatment with UF membranes.

    Science.gov (United States)

    Salazar-Peláez, M L; Morgan-Sagastume, J M; Noyola, A

    2011-01-01

    A pilot UASB reactor coupled with an external ultrafiltration (UF) membrane was operated under three different hydraulic retention times (HRT) for domestic wastewater treatment. The aim was to assess the HRT influence on system performance and fouling. The highest concentrations of COD, total solids, extracellular polymeric substances (EPS) and soluble microbial products (SMP) in UASB effluent and permeate were found when the UASB reactor was operated under the lowest HRT studied (4 hours); although the fulfillment of Mexican Standard for wastewater reclamation was not compromised. This fact could be attributed to the higher shear stress forces inside the UASB reactor when it was operated at low HRT, which promoted the release of biopolymeric substances in its effluent. Besides, the fouling propensity in the UASB effluent was worsened with HRT reduction, by increasing the fouling rate and the specific cake resistance. Based on these results, it is recommended to avoid operating the UASB reactor at low HRTs (less than 4 hours) in order to control SMP and EPS fouling potential. The results presented also suggest that HRT reduction has a detrimental effect on performance and fouling.

  20. The effect of organic loading rate and retention time on hydrogen production from a methanogenic CSTR.

    Science.gov (United States)

    Pakarinen, O; Kaparaju, P; Rintala, J

    2011-10-01

    The possibility of shifting a methanogenic process for hydrogen production by changing the process parameters viz., organic loading rate (OLR) and hydraulic retention time (HRT) was evaluated. At first, two parallel semi-continuously fed continuously stirred tank reactors (CSTR) were operated as methanogenic reactors (M1 and M2) for 78 days. Results showed that a methane yield of 198-218 L/kg volatile solids fed (VS(fed)) was obtained when fed with grass silage at an OLR of 2 kgVS/m³/d and HRT of 30 days. After 78 days of operation, hydrogen production was induced in M2 by increasing the OLR from 2 to 10 kgVS/m³/d and shortening the HRT from 30 to 6 days. The highest H₂ yield of 42 L/kgVS(fed) was obtained with a maximum H₂ content of 24%. The present results thus demonstrate that methanogenic process can be shifted towards hydrogen production by increasing the OLR and decreasing HRT. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Impact of sludge retention time on sludge characteristics and microbial community in MBR.

    Science.gov (United States)

    Su, Yuchun; Pan, Jill Ruhsing; Huang, Chihpin; Chang, Chialing

    2011-01-01

    In this study, the impact of sludge retention time (SRT) on sludge characteristics and microbial community and the effect on membrane fouling in membrane bioreactor (MBR) was investigated. The results show that MBR with longer SRT has less fouling propensity, in agreement with other studies, despite the fact that the MBR with longer SRT contained higher MLSS and smaller particle size. However, much more soluble microbial products (SMPs) were released in MBR with shorter SRT. More slime on the membrane surface was observed in MBR with shorter SRT while sludge cakes formed on the membrane surface in MBR with longer SRT. The results show that SMP contributes to the severe fouling observed in MBR with shorter SRT, which is in agreement with other studies showing that SMPs were the major foulants in MBR. Under different SRTs of operation, the bacterial community structures of the sludge obtained by use of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) were almost identical, but those on the membrane surface differed substantially. It suggests that, although SRT has impact on sludge characteristics, it doesn't affect the microbial community in the suspension.

  2. Nonunitary similarity transformation of conservative to dissipative evolutions: Intertwining without time operator

    Science.gov (United States)

    Gómez, Fernando

    2007-04-01

    Reversible evolutions are usually expressed in terms of unitary groups on separable Hilbert spaces, whereas irreversible ones are described by contraction semigroups. In the theory of nonunitary similarity transformations intertwining unitary groups and contraction semigroups, proposed initially in the context of statistical mechanics as part of an exact theory of irreversibility, the unitary groups with such intertwining property have been qualified by the existence of an internal time operator. This work tackles the question of existence of internal time operators for unitary groups with the intertwining property. Equivalent conditions to the existence of internal time operators for such unitary groups are given on the basis of the Sz.-Nagy-Foiaş [Harmonic Analysis of Operators on Hilbert Spaces (North-Holland, Amsterdam, 1970)] dilation theory and the theory of shift invariant subspaces. These conditions permit us to solve the inverse intertwining problem in the negative: there are unitary groups with the intertwining property which do not admit internal time operator. A representative family of such unitary groups is given.

  3. Microbubble responses to a similar mechanical index with different real-time perfusion imaging techniques.

    Science.gov (United States)

    Porter, Thomas R; Oberdorfer, Joseph; Rafter, Patrick; Lof, John; Xie, Feng

    2003-08-01

    The purpose of this study was to determine differences in contrast enhancement and microbubble destruction rates with current commercially available low-mechanical index (MI) real-time perfusion imaging modalities. A tissue-mimicking phantom was developed that had vessels at 3 cm (near field) and 9 cm (far field) from a real-time transducer. Perfluorocarbon-exposed sonicated dextrose albumin microbubbles (PESDA) were injected proximal to a mixing chamber, and then passed through these vessels while the region was insonified with either pulses of alternating polarity with pulse inversion Doppler (PID) or pulses of alternating amplitude by power modulation (PM) at MIs of 0.1, 0.2 and 0.3. Effluent microbubble concentration, contrast intensity and the slope of digital contrast intensity vs. time were measured. Our results demonstrated that microbubble destruction already occurs with PID at an MI of 0.1. Contrast intensity seen with PID was less than with PM. Therefore, differences in contrast enhancement and microbubble destruction rates occur at a similar MI setting when using different real-time pulse sequence schemes.

  4. Simplified tools for measuring retention in care in antiretroviral treatment program in Ethiopia: cohort and current retention in care.

    Science.gov (United States)

    Assefa, Yibeltal; Worku, Alemayehu; Wouters, Edwin; Koole, Olivier; Haile Mariam, Damen; Van Damme, Wim

    2012-01-01

    Patient retention in care is a critical challenge for antiretroviral treatment programs. This is mainly because retention in care is related to adherence to treatment and patient survival. It is therefore imperative that health facilities and programs measure patient retention in care. However, the currently available tools, such as Kaplan Meier, for measuring retention in care have a lot of practical limitations. The objective of this study was to develop simplified tools for measuring retention in care. Retrospective cohort data were collected from patient registers in nine health facilities in Ethiopia. Retention in care was the primary outcome for the study. Tools were developed to measure "current retention" in care during a specific period of time for a specific "ART-age group" and "cohort retention" in care among patients who were followed for the last "Y" number of years on ART. "Probability of retention" based on the tool for "cohort retention" in care was compared with "probability of retention" based on Kaplan Meier. We found that the new tools enable to measure "current retention" and "cohort retention" in care. We also found that the tools were easy to use and did not require advanced statistical skills. Both "current retention" and "cohort retention" are lower among patients in the first two "ART-age groups" and "ART-age cohorts" than in subsequent "ART-age groups" and "ART-age cohorts". The "probability of retention" based on the new tools were found to be similar to the "probability of retention" based on Kaplan Meier. The simplified tools for "current retention" and "cohort retention" will enable practitioners and program managers to measure and monitor rates of retention in care easily and appropriately. We therefore recommend that health facilities and programs start to use these tools in their efforts to improve retention in care and patient outcomes.

  5. Simplified tools for measuring retention in care in antiretroviral treatment program in Ethiopia: cohort and current retention in care.

    Directory of Open Access Journals (Sweden)

    Yibeltal Assefa

    Full Text Available INTRODUCTION: Patient retention in care is a critical challenge for antiretroviral treatment programs. This is mainly because retention in care is related to adherence to treatment and patient survival. It is therefore imperative that health facilities and programs measure patient retention in care. However, the currently available tools, such as Kaplan Meier, for measuring retention in care have a lot of practical limitations. The objective of this study was to develop simplified tools for measuring retention in care. METHODS: Retrospective cohort data were collected from patient registers in nine health facilities in Ethiopia. Retention in care was the primary outcome for the study. Tools were developed to measure "current retention" in care during a specific period of time for a specific "ART-age group" and "cohort retention" in care among patients who were followed for the last "Y" number of years on ART. "Probability of retention" based on the tool for "cohort retention" in care was compared with "probability of retention" based on Kaplan Meier. RESULTS: We found that the new tools enable to measure "current retention" and "cohort retention" in care. We also found that the tools were easy to use and did not require advanced statistical skills. Both "current retention" and "cohort retention" are lower among patients in the first two "ART-age groups" and "ART-age cohorts" than in subsequent "ART-age groups" and "ART-age cohorts". The "probability of retention" based on the new tools were found to be similar to the "probability of retention" based on Kaplan Meier. CONCLUSION: The simplified tools for "current retention" and "cohort retention" will enable practitioners and program managers to measure and monitor rates of retention in care easily and appropriately. We therefore recommend that health facilities and programs start to use these tools in their efforts to improve retention in care and patient outcomes.

  6. Study of bioleaching under different hydraulic retention time for enhancing the dewaterability of digestate.

    Science.gov (United States)

    Li, Linshuai; Gao, Jingqing; Zhu, Songfeng; Li, Yonghong; Zhang, Ruiqin

    2015-12-01

    Dewatering of kitchen waste digestate is a key problem to solve so as to increase the application of kitchen waste after anaerobic digestion. In this study, the effects of bioleaching under different hydraulic retention time (HRT = 2, 2.5, and 3 days) on dewaterability of kitchen waste digestate were evaluated. A 12-stage plug flow bioreactor with 180 L working volume was used for digestate bioleaching. The bioleached digestate under different HRTs were collected and dewatered by plate-and-frame filter press. The results showed that the moisture contents of digestate cakes were 67.87 % at 2 days of HRT, 58.06 % at 2.5 days of HRT, and 54.45 % at 3 days of HRT, respectively, indicating the longer the HRT, the lower the moisture content of filter cake. Balanced between the cost and practical need, 2.5 days can be used as the HRT in engineering application. Under the condition of HRT of 2.5 days, the pH, specific resistance to filtration (SRF), capillary suction time (CST), and sedimentation rate of digestate changed from the initial values of 8.08, 210.6 s, 23.4 × 10(12) m kg(-1) and 10 % to 3.21, 32.7 s, 2.44 × 10(12) m kg(-1) and 76.8 %, respectively. Based on the observations above, the authors conclude that bioleaching technology is an effective method to enhance digestate dewaterability and reduce the cost of subsequent reutilization.

  7. Effect of prolonging radiation delivery time on retention of gammaH2AX

    International Nuclear Information System (INIS)

    Moiseenko, Vitali; Banáth, Judit P; Duzenli, Cheryl; Olive, Peggy L

    2008-01-01

    Compared to conventional external beam radiotherapy, IMRT requires significantly more time to deliver the dose. Prolonging dose delivery potentially increases DNA repair which would reduce the biological effect. We questioned whether retention of γH2AX, a measure of lack of repair of DNA damage, would decrease when dose delivery was protracted. Exponentially growing SiHa cervical carinoma cells were irradiated with 6 MV photons in a water tank using a VarianEX linear accelerator. Cells held at 37°C received 2 Gy in 0.5 min and 4 Gy in 1 min. To evaluate effect of dose delivery prolongation, 2 and 4 Gy were delivered in 30 and 60 min. After 24 h recovery, cells were analyzed for clonogenic survival and for residual γH2AX as measured using flow cytometry. Increasing the dose delivery time from 0.5 or 1 min to 30 or 60 min produced a signficant increase in cell survival from 0.45 to 0.48 after 2 Gy, and from 0.17 to 0.20 after 4 Gy. Expression of residual γH2AX decreased from 1.27 to 1.22 relative to background after 2 Gy and 1.46 to 1.39 relative to background after 4 Gy, but differences were not statistically significant. The relative differences in the slopes of residual γH2AX versus dose for acute versus prolonged irradiation bordered on significant (p = 0.055), and the magnitude of the change was consistent with the observed increase in surviving fraction. These results support the concept that DNA repair underlies the increase in survival observed when dose delivery is prolonged. They also help to establish the limits of sensitivity of residual γH2AX, as measured using flow cytometry, for detecting differences in response to irradiation

  8. Maximizing the retention level for proportional reinsurance under  -regulation of the finite time surplus process with unit-equalized interarrival time

    Directory of Open Access Journals (Sweden)

    Sukanya Somprom

    2016-07-01

    Full Text Available The research focuses on an insurance model controlled by proportional reinsurance in the finite-time surplus process with a unit-equalized time interval. We prove the existence of the maximal retention level for independent and identically distributed claim processes under α-regulation, i.e., a model where the insurance company has to manage the probability of insolvency to be at most α. In addition, we illustrate the maximal retention level for exponential claims by applying the bisection technique.

  9. Similar star formation rate and metallicity variability time-scales drive the fundamental metallicity relation

    Science.gov (United States)

    Torrey, Paul; Vogelsberger, Mark; Hernquist, Lars; McKinnon, Ryan; Marinacci, Federico; Simcoe, Robert A.; Springel, Volker; Pillepich, Annalisa; Naiman, Jill; Pakmor, Rüdiger; Weinberger, Rainer; Nelson, Dylan; Genel, Shy

    2018-06-01

    The fundamental metallicity relation (FMR) is a postulated correlation between galaxy stellar mass, star formation rate (SFR), and gas-phase metallicity. At its core, this relation posits that offsets from the mass-metallicity relation (MZR) at a fixed stellar mass are correlated with galactic SFR. In this Letter, we use hydrodynamical simulations to quantify the time-scales over which populations of galaxies oscillate about the average SFR and metallicity values at fixed stellar mass. We find that Illustris and IllustrisTNG predict that galaxy offsets from the star formation main sequence and MZR oscillate over similar time-scales, are often anticorrelated in their evolution, evolve with the halo dynamical time, and produce a pronounced FMR. Our models indicate that galaxies oscillate about equilibrium SFR and metallicity values - set by the galaxy's stellar mass - and that SFR and metallicity offsets evolve in an anticorrelated fashion. This anticorrelated variability of the metallicity and SFR offsets drives the existence of the FMR in our models. In contrast to Illustris and IllustrisTNG, we speculate that the SFR and metallicity evolution tracks may become decoupled in galaxy formation models dominated by feedback-driven globally bursty SFR histories, which could weaken the FMR residual correlation strength. This opens the possibility of discriminating between bursty and non-bursty feedback models based on the strength and persistence of the FMR - especially at high redshift.

  10. Analysis and Modeling of Time-Correlated Characteristics of Rainfall-Runoff Similarity in the Upstream Red River Basin

    Directory of Open Access Journals (Sweden)

    Xiuli Sang

    2012-01-01

    Full Text Available We constructed a similarity model (based on Euclidean distance between rainfall and runoff to study time-correlated characteristics of rainfall-runoff similar patterns in the upstream Red River Basin and presented a detailed evaluation of the time correlation of rainfall-runoff similarity. The rainfall-runoff similarity was used to determine the optimum similarity. The results showed that a time-correlated model was found to be capable of predicting the rainfall-runoff similarity in the upstream Red River Basin in a satisfactory way. Both noised and denoised time series by thresholding the wavelet coefficients were applied to verify the accuracy of model. And the corresponding optimum similar sets obtained as the equation solution conditions showed an interesting and stable trend. On the whole, the annual mean similarity presented a gradually rising trend, for quantitatively estimating comprehensive influence of climate change and of human activities on rainfall-runoff similarity.

  11. The influence of solid retention time on IFAS-MBR systems: Assessment of nitrous oxide emission.

    Science.gov (United States)

    Mannina, Giorgio; Capodici, Marco; Cosenza, Alida; Laudicina, Vito Armando; Di Trapani, Daniele

    2017-12-01

    The aim of the present study was to investigate the nitrous oxide (N 2 O) emissions from a moving bed based Integrated Fixed Film Activated Sludge (IFAS) - membrane bioreactor (MBR) pilot plant, designed according to the University of Cape Town (UCT) layout. The experimental campaign had a duration of 110 days and was characterized by three different sludge retention time (SRT) values (∞, 30 d and 15 d). Results highlighted that N 2 O concentrations decreased when the biofilm concentrations increased within the aerobic reactor. Results have shown an increase of N 2 O with the decrease of SRT. Specifically, an increase of N 2 O-N emission factor occurred with the decrease of the SRT (0.13%, 0.21% and 0.76% of influent nitrogen for SRT = ∞, SRT = 30 d and SRT = 15 d, respectively). Moreover, the MBR tank resulted the key emission source (up to 70% of the total N 2 O emission during SRT = ∞ period) whereas the highest N 2 O production occurred in the anoxic reactor. Moreover, N 2 O concentrations measured in the permeate flow were not negligible, thus highlighting its potential detrimental contribution for the receiving water body. The role of each plant reactor as N 2 O-N producer/consumer varies with the SRT variation, indeed the aerobic reactor was a N 2 O consumer at SRT = ∞ and a producer at SRT = 30 d. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Effects of Hydraulic Retention Time on the Performance of a Membrane Bioreactor Treating Municipal Wastewater

    Directory of Open Access Journals (Sweden)

    Hadi Falahati

    2017-09-01

    Full Text Available There is an increasing demand for effluents of higher quality from wastewater treatment plants due to the more stringent quality standards as well as the increasing pressure on water resources worldwide, which calls for effluent recycle and reuse. Membrane bioreactors (MBRs have been recently gaining rapid popularity as a promising technology for wastewater treatment. In order to improve the quality of the effluent from Shiraz wastewater treatment plant, an on-site pilot-scale membrane bioreactor was operated for 9 months. The pilot plant built at Shiraz wastewater treatment plant consisted of an aerobic reactor and a membrane compartment containing one submerged hollow fiber membrane module. In this study, eleven different aerobic hydraulic retention times (HRT ranging from 2 to 12 hours were tested to determine the membrane capacity and to investigate the performance of the system in removing total ammonia nitrogen, organic matter, total suspended solids, and turbidity.The system recorded a perfectly stable removal efficiency over the whole experimental period, except for the 2-hour aerobic HRT, so that its COD and BOD reductions exceeded 95% and 99%, respectively. Moreover, the system achieved complete nitrification in a stable manner during the whole study period, except for the 2-hour aerobic operation period. TSS concentration was almost zero and turbidity was less than 1 NTU. Membrane capacity measurements showed an average flux of 5.5 Lm-2h-1 with a mean trans-membrane pressure difference of 30 kPa. Results showed that the MBR outperformed the conventional sewage treatment processes. Additionally, it was not affected by aerobic HRT changes (12, 10, 8, 6, 4, and 3h. Based on the effluent qulity, teh system may be recommended for application toward water reuse in industrial and agricultural settings

  13. The retention time of inorganic mercury in the brain — A systematic review of the evidence

    Energy Technology Data Exchange (ETDEWEB)

    Rooney, James P.K., E-mail: jrooney@rcsi.ie

    2014-02-01

    Reports from human case studies indicate a half-life for inorganic mercury in the brain in the order of years—contradicting older radioisotope studies that estimated half-lives in the order of weeks to months in duration. This study systematically reviews available evidence on the retention time of inorganic mercury in humans and primates to better understand this conflicting evidence. A broad search strategy was used to capture 16,539 abstracts on the Pubmed database. Abstracts were screened to include only study types containing relevant information. 131 studies of interest were identified. Only 1 primate study made a numeric estimate for the half-life of inorganic mercury (227–540 days). Eighteen human mercury poisoning cases were followed up long term including autopsy. Brain inorganic mercury concentrations at death were consistent with a half-life of several years or longer. 5 radionucleotide studies were found, one of which estimated head half-life (21 days). This estimate has sometimes been misinterpreted to be equivalent to brain half-life—which ignores several confounding factors including limited radioactive half-life and radioactive decay from surrounding tissues including circulating blood. No autopsy cohort study estimated a half-life for inorganic mercury, although some noted bioaccumulation of brain mercury with age. Modelling studies provided some extreme estimates (69 days vs 22 years). Estimates from modelling studies appear sensitive to model assumptions, however predications based on a long half-life (27.4 years) are consistent with autopsy findings. In summary, shorter estimates of half-life are not supported by evidence from animal studies, human case studies, or modelling studies based on appropriate assumptions. Evidence from such studies point to a half-life of inorganic mercury in human brains of several years to several decades. This finding carries important implications for pharmcokinetic modelling of mercury and potentially for

  14. The retention time of inorganic mercury in the brain — A systematic review of the evidence

    International Nuclear Information System (INIS)

    Rooney, James P.K.

    2014-01-01

    Reports from human case studies indicate a half-life for inorganic mercury in the brain in the order of years—contradicting older radioisotope studies that estimated half-lives in the order of weeks to months in duration. This study systematically reviews available evidence on the retention time of inorganic mercury in humans and primates to better understand this conflicting evidence. A broad search strategy was used to capture 16,539 abstracts on the Pubmed database. Abstracts were screened to include only study types containing relevant information. 131 studies of interest were identified. Only 1 primate study made a numeric estimate for the half-life of inorganic mercury (227–540 days). Eighteen human mercury poisoning cases were followed up long term including autopsy. Brain inorganic mercury concentrations at death were consistent with a half-life of several years or longer. 5 radionucleotide studies were found, one of which estimated head half-life (21 days). This estimate has sometimes been misinterpreted to be equivalent to brain half-life—which ignores several confounding factors including limited radioactive half-life and radioactive decay from surrounding tissues including circulating blood. No autopsy cohort study estimated a half-life for inorganic mercury, although some noted bioaccumulation of brain mercury with age. Modelling studies provided some extreme estimates (69 days vs 22 years). Estimates from modelling studies appear sensitive to model assumptions, however predications based on a long half-life (27.4 years) are consistent with autopsy findings. In summary, shorter estimates of half-life are not supported by evidence from animal studies, human case studies, or modelling studies based on appropriate assumptions. Evidence from such studies point to a half-life of inorganic mercury in human brains of several years to several decades. This finding carries important implications for pharmcokinetic modelling of mercury and potentially for

  15. Role of hydraulic retention time and granular medium in microbial removal in tertiary treatment reed beds.

    Science.gov (United States)

    García, Joan; Vivar, Joan; Aromir, Maria; Mujeriego, Rafael

    2003-06-01

    The main objective of this paper is to evaluate the role of hydraulic retention time (HRT) and granular medium in faecal coliform (FC) and somatic coliphage (SC) removal in tertiary reed beds. Experiments were carried out in a pilot plant with four parallel reed beds (horizontal subsurface flow constructed wetlands), each one containing a different type of granular medium. This pilot plant is located in a wastewater treatment plant in Montcada i Reixac, near Barcelona, in northeastern Spain. The microbial inactivation ratios obtained in the different beds are compared as a function of three selected HRTs. Secondary effluent from the wastewater treatment plant was used as the influent of the pilot system. The microbial inactivation ratio ranged between 0.1 and 2.7 log-units for FC and from 0.5 to 1.7 log-units for SC in beds with coarser granular material (5-25mm), while it ranged between 0.7 and 3.4 log-units for FC and from 0.9 to 2.6 log-units for SC in the bed with finer material (2-13mm). HRT and granular medium are both key factors in microbial removal in the tertiary reed beds. The microbial inactivation ratio rises as the HRT increases until it reaches a saturation value (in general at an HRT of 3 days). The value of the microbial inactivation ratio at the saturation level depends on the granular medium contained in the bed. The specific surface area necessary to reach 2-3 log-units of FC and SC is approximately 3m(2)/person-equivalent.

  16. How Similar Are Forest Disturbance Maps Derived from Different Landsat Time Series Algorithms?

    Directory of Open Access Journals (Sweden)

    Warren B. Cohen

    2017-03-01

    Full Text Available Disturbance is a critical ecological process in forested systems, and disturbance maps are important for understanding forest dynamics. Landsat data are a key remote sensing dataset for monitoring forest disturbance and there recently has been major growth in the development of disturbance mapping algorithms. Many of these algorithms take advantage of the high temporal data volume to mine subtle signals in Landsat time series, but as those signals become subtler, they are more likely to be mixed with noise in Landsat data. This study examines the similarity among seven different algorithms in their ability to map the full range of magnitudes of forest disturbance over six different Landsat scenes distributed across the conterminous US. The maps agreed very well in terms of the amount of undisturbed forest over time; however, for the ~30% of forest mapped as disturbed in a given year by at least one algorithm, there was little agreement about which pixels were affected. Algorithms that targeted higher-magnitude disturbances exhibited higher omission errors but lower commission errors than those targeting a broader range of disturbance magnitudes. These results suggest that a user of any given forest disturbance map should understand the map’s strengths and weaknesses (in terms of omission and commission error rates, with respect to the disturbance targets of interest.

  17. Similarity transformed coupled cluster response (ST-CCR) theory--a time-dependent similarity transformed equation-of-motion coupled cluster (STEOM-CC) approach.

    Science.gov (United States)

    Landau, Arie

    2013-07-07

    This paper presents a new method for calculating spectroscopic properties in the framework of response theory utilizing a sequence of similarity transformations (STs). The STs are preformed using the coupled cluster (CC) and Fock-space coupled cluster operators. The linear and quadratic response functions of the new similarity transformed CC response (ST-CCR) method are derived. The poles of the linear response yield excitation-energy (EE) expressions identical to the ones in the similarity transformed equation-of-motion coupled cluster (STEOM-CC) approach. ST-CCR and STEOM-CC complement each other, in analogy to the complementarity of CC response (CCR) and equation-of-motion coupled cluster (EOM-CC). ST-CCR/STEOM-CC and CCR/EOM-CC yield size-extensive and size-intensive EEs, respectively. Other electronic-properties, e.g., transition dipole strengths, are also size-extensive within ST-CCR, in contrast to STEOM-CC. Moreover, analysis suggests that in comparison with CCR, the ST-CCR expressions may be confined to a smaller subspace, however, the precise scope of the truncation can only be determined numerically. In addition, reformulation of the time-independent STEOM-CC using the same parameterization as in ST-CCR, as well as an efficient truncation scheme, is presented. The shown convergence of the time-dependent and time-independent expressions displays the completeness of the presented formalism.

  18. One-year retention of general and sequence-specific skills in a probabilistic, serial reaction time task.

    Science.gov (United States)

    Romano, Jennifer C; Howard, James H; Howard, Darlene V

    2010-05-01

    Procedural skills such as riding a bicycle and playing a musical instrument play a central role in daily life. Such skills are learned gradually and are retained throughout life. The present study investigated 1-year retention of procedural skill in a version of the widely used serial reaction time task (SRTT) in young and older motor-skill experts and older controls in two experiments. The young experts were college-age piano and action video-game players, and the older experts were piano players. Previous studies have reported sequence-specific skill retention in the SRTT as long as 2 weeks but not at 1 year. Results indicated that both young and older experts and older non-experts revealed sequence-specific skill retention after 1 year with some evidence that general motor skill was retained as well. These findings are consistent with theoretical accounts of procedural skill learning such as the procedural reinstatement theory as well as with previous studies of retention of other motor skills.

  19. The human body retention time of environmental organically bound Tritium : preliminary analysis of results from a volunteer study

    International Nuclear Information System (INIS)

    Hunt, John; Bailey, Trevor; Reese, Allan

    2008-01-01

    Tritium in the UK environment causes low radiation doses to the public, but uncertainty exists in the dose coefficient for the organically-bound component of tritium (OBT). This can affect the assessment of effective doses to representative persons. Contributing to that uncertainty is poor knowledge of the body retention time of OBT and how this varies for different OBT compounds in food. This study was undertaken to measure the retention time of tritium by volunteers after eating sole from Cardiff Bay, which may contain OBT from discharges from the GE Healthcare Ltd. plant. Five volunteers provided samples of excreta over periods up to 150 days after intake. Preliminary analysis of the results suggests retention of total tritium with body half-times ranging from 4 to 11 days, with no evidence of a significant contribution due to retention with a longer half-time. This range covers the half-time of 10 days used by the ICRP for tritiated water. The short timescale could be due to rapid hydrolysis in body tissues of the particular form of OBT used in this study. Implications for the dose coefficient for OBT are that the use of the ICRP value of 4.2 10- 11 Sv Bq -1 may be cautious in this specific situation, and the value of 1.6 10 -11 Sv Bq-1 used by the ICRP for tritiated water might even be more appropriate. These observations on dose coefficients are separate from any implications of recent discussion on whether the tritium radiation weighting factor should be increased from 1 to 2. (author)

  20. Measuring time series regularity using nonlinear similarity-based sample entropy

    International Nuclear Information System (INIS)

    Xie Hongbo; He Weixing; Liu Hui

    2008-01-01

    Sampe Entropy (SampEn), a measure quantifying regularity and complexity, is believed to be an effective analyzing method of diverse settings that include both deterministic chaotic and stochastic processes, particularly operative in the analysis of physiological signals that involve relatively small amount of data. However, the similarity definition of vectors is based on Heaviside function, of which the boundary is discontinuous and hard, may cause some problems in the validity and accuracy of SampEn. Sigmoid function is a smoothed and continuous version of Heaviside function. To overcome the problems SampEn encountered, a modified SampEn (mSampEn) based on nonlinear Sigmoid function was proposed. The performance of mSampEn was tested on the independent identically distributed (i.i.d.) uniform random numbers, the MIX stochastic model, the Rossler map, and the Hennon map. The results showed that mSampEn was superior to SampEn in several aspects, including giving entropy definition in case of small parameters, better relative consistency, robust to noise, and more independence on record length when characterizing time series generated from either deterministic or stochastic system with different regularities

  1. Effects of sludge retention time (SRT) and biosurfactant on the removal of polyaromatic compounds and toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Sponza, Delia Teresa, E-mail: delya.sponza@deu.edu.tr [Dokuz Eylul University, Engineering Faculty, Environmental Engineering Department, Buca Kaynaklar Campus, 35160 Izmir (Turkey); Gok, Oguzhan [Dokuz Eylul University, Engineering Faculty, Environmental Engineering Department, Buca Kaynaklar Campus, 35160 Izmir (Turkey)

    2011-12-15

    Graphical abstract: Acute toxicities in (a) influent wastewater (EC{sub 50} = 45.02 ng ml{sup -1}) and (b) effluent wastewater in aerobic activated sludge reactor at SRT = 25 days (EC{sub 6} = 5.30 ng ml{sup -1}). Highlights: Black-Right-Pointing-Pointer Over 90% of the total PAHs was removed at Rhamnolipid and sludge retention time of 15 mg l{sup -1} and 25 days. Black-Right-Pointing-Pointer 93% of the COD originating from the inert organics was removed in the aerobic reactor. 96-97% of the Rhamnolipid was biodegraded. Black-Right-Pointing-Pointer The EC50 value was reduced from EC{sub 50} = 45.02 ng ml{sup -1} to C{sub 6} = 5.30 ng ml{sup -1} with Daphnia magna. Toxicity removals originating from the PAHs were 96%. - Abstract: A laboratory-scale aerobic activated sludge reactor (AASR) system was employed to investigate the effects of SRT on the removal of three less hydrophobic and six more hydrophobic PAHs in the presence of rhamnolipid (RD), emulsan (EM) and surfactine (SR) biosurfactants. Among the biosurfactants it was found that RD exhibits a better performance than the others in the removal of PAHs. At a RD of 15 mg l{sup -1} aerobic treatment for 25 days SRT was enough to remove over 90% of the total PAHs, 88% of the COD originating from the inert organics (COD{sub inert}) and 93% of the COD originating from the inert soluble microbial products (COD{sub imp}). At this SRT and RD concentration, about 96-98% of the RD was biodegraded by the AASR system, 1.2-1.4% was accumulated in the system, 1.1-1.3% was released in the effluent, and 1.2-1.4% remained in the waste sludge. The addition of electron acceptors (NO{sub 3}{sup -1}, SO{sub 4}{sup -2}) and increasing of temperature up to 45 Degree-Sign C enhanced the PAH yields. The most effective PAH degradation occurred in high-oxygenated and neutral pH conditions. The PAH concentration affecting half of the Daphnia magna organism (EC{sub 50} value) was reduced from EC{sub 50} = 45.02 ng ml{sup -1} to the PAH

  2. Effects of sludge retention time (SRT) and biosurfactant on the removal of polyaromatic compounds and toxicity

    International Nuclear Information System (INIS)

    Sponza, Delia Teresa; Gok, Oguzhan

    2011-01-01

    Graphical abstract: Acute toxicities in (a) influent wastewater (EC 50 = 45.02 ng ml −1 ) and (b) effluent wastewater in aerobic activated sludge reactor at SRT = 25 days (EC 6 = 5.30 ng ml −1 ). Highlights: ► Over 90% of the total PAHs was removed at Rhamnolipid and sludge retention time of 15 mg l −1 and 25 days. ► 93% of the COD originating from the inert organics was removed in the aerobic reactor. 96–97% of the Rhamnolipid was biodegraded. ► The EC50 value was reduced from EC 50 = 45.02 ng ml −1 to C 6 = 5.30 ng ml −1 with Daphnia magna. Toxicity removals originating from the PAHs were 96%. - Abstract: A laboratory-scale aerobic activated sludge reactor (AASR) system was employed to investigate the effects of SRT on the removal of three less hydrophobic and six more hydrophobic PAHs in the presence of rhamnolipid (RD), emulsan (EM) and surfactine (SR) biosurfactants. Among the biosurfactants it was found that RD exhibits a better performance than the others in the removal of PAHs. At a RD of 15 mg l −1 aerobic treatment for 25 days SRT was enough to remove over 90% of the total PAHs, 88% of the COD originating from the inert organics (COD inert ) and 93% of the COD originating from the inert soluble microbial products (COD imp ). At this SRT and RD concentration, about 96–98% of the RD was biodegraded by the AASR system, 1.2–1.4% was accumulated in the system, 1.1–1.3% was released in the effluent, and 1.2–1.4% remained in the waste sludge. The addition of electron acceptors (NO 3 −1 , SO 4 −2 ) and increasing of temperature up to 45 °C enhanced the PAH yields. The most effective PAH degradation occurred in high-oxygenated and neutral pH conditions. The PAH concentration affecting half of the Daphnia magna organism (EC 50 value) was reduced from EC 50 = 45.02 ng ml −1 to the PAH concentration affecting only 6% of the live Daphnia magna (EC 6 = 5.30 ng ml −1 ) at the end of the aerobic treatment at a SRT of 25 days. Toxicity

  3. Urinary Retention

    Science.gov (United States)

    ... 2011. [4] Mevcha A, Drake MJ. Etiology and management of urinary retention in women. Indian Journal of Urology. 2010;26(2):230–235. August ... 30 a.m. to 5 p.m. eastern time, M-F Follow Us NIH… Turning Discovery Into ... Disease Urologic Diseases Endocrine Diseases Diet & Nutrition ...

  4. Time-Series Similarity Analysis of Satellite Derived Data to Understand Changes in Forest Biomass.

    Science.gov (United States)

    Singh, N.; Fritz, B.

    2017-12-01

    One of the goals of promoting bioenergy is reducing green-house gas emissions by replacing fossil fuels. However, there are concerns that carbon emissions due to changes in land use resulting from crop production for ethanol will negate the impact of biofuels on the environment. So, the current focus is to use lignocellulose feedstocks also referred to as second generation biofuels as the new source of bioenergy. Wood based pellets derived from the forests of southeastern United States are one such source which is being exported to Europe as a carbon-neutral fuel. These wood-pellets meet the EU standard for carbon emissions and are being used to replace coal for energy generation and heating. As a result US exports of wood-based pellets have increased from nearly zero to over 6 million metric tons over the past 8 years. Wood-based pellets are traditionally produced from softwood trees which have a relatively shorter life-cycle and propagate easily, and thus are expected to provide a sustainable source of wood chips used for pellet production. However, there are concerns that as the demand and price of wood pellets increases, lumber mills will seek wood chips from other sources as well, particularly from hardwood trees resulting in higher carbon emissions as well as loss of biodiversity. In this study we use annual stacks of normalized difference vegetation index (NDVI) data at a 16-day temporal resolution to monitor biomass around pellet mills in southeastern United States. We use a combination of time series similarity technique and supervised learning to understand if there have been significant changes in biomass around pellet mills in the southeastern US. We also demonstrate how our method can be used to monitor biomass over large geographic regions using phenological properties of growing vegetation.

  5. Investigating the Effects of Three Needling Parameters (Manipulation, Retention Time, and Insertion Site) on Needling Sensation and Pain Profiles: A Study of Eight Deep Needling Interventions

    Science.gov (United States)

    Loyeung, Bertrand Y. K.; Cobbin, Deirdre M.

    2013-01-01

    Introduction. In traditional Chinese acupuncture, needle sensation (deqi) is purported to contribute to a therapeutic outcome. While researchers have attempted to define deqi qualitatively, few have examined the effects of needling parameters on its intensity. Methods. 24 healthy subjects completed eight interventions scheduled at least one week apart, which involved manual acupuncture to LI4 or a designated nonacupoint (NAP) on the hand, with real or simulated manipulation each three minutes and needle retentions of one or 21 minutes. Intensities of needling sensation and pain were reported every three minutes and sensation qualities were reported post-intervention. Results. Immediately after needle insertion, similar levels of mean needle sensation and of pain were reported independent of intervention. At subsequent measurement times, only two interventions (one at LI4 and one at NAP) maintained statistically significantly elevated needle sensation and pain scores and reported higher numbers of needle sensation descriptors. For both, the needle was retained for 21 minutes and manipulated every three minutes. Neither intervention differed significantly in terms of levels of pain, and needle sensation or numbers and qualities of needle sensation described. Conclusion. In this group of healthy subjects, the initial needling for all eight interventions elicited similar levels of needle sensation and pain. These levels were only maintained if there was ongoing of needle manipulation and retention of the needle. By contrast, the strength of needle sensation or pain experienced was independent of insertion site. PMID:24159337

  6. Similarity solutions for explosions in radiating stars with time-dependent energy and idealized magnetic field

    International Nuclear Information System (INIS)

    Verma, G.B.; Vishwakarma, J.P.; Sharan, V.

    1983-01-01

    A stellar model in which density in the undisturbed conducting-gas medium is assumed to obey a power law is considered. Similarity solutions for central explosion in radiating stars have been obtained under the assumption of isothermal-shock conditions. For the existence of self-similar character, it has been assumed that both radiation pressure and energy are negligible. The results of numerical calculations for different models are illustrated through graphs. Moreover, a comparative study has been made between the results in ordinary gasdynamics and those obtained in magnetogasdynamics

  7. The effect of hydraulic retention time in onsite wastewater treatment and removal of pharmaceuticals, hormones and phenolic utility substances.

    Science.gov (United States)

    Ejhed, H; Fång, J; Hansen, K; Graae, L; Rahmberg, M; Magnér, J; Dorgeloh, E; Plaza, G

    2018-03-15

    Micropollutants such as pharmaceuticals, hormones and phenolic utility chemicals in sewage water are considered to be an emerging problem because of increased use and observed adverse effects in the environment. The study provides knowledge on the removal efficiency of micropollutants with a range of physical and chemical properties in three commercially available onsite wastewater treatment facilities (OWTFs), tested on influent wastewater collected from 2500 person equivalents in Bildchen, Germany. A longer hydraulic retention time would in theory be expected to have a positive effect, and this study presents results for three different OWTFs in full-scale comparable tests under natural conditions. A range of 24 different pharmaceuticals, five phenols and three hormones were analyzed. Flow-proportional consecutive sampling was performed in order to determine the removal efficiency. Twenty-eight substances were detected in the effluent wastewater out of 32 substances included. Average effluent concentrations of Simvastatin, Estrone, Estradiol and Ethinylestradiol were above the indicative critical-effect concentration of pharmacological effect on fish in all facilities. Average effluent concentrations of both Diclofenac and Estradiol were higher than the Environmental Quality Standards applied in Sweden (190-240 times and 9-35 times respectively). The removal efficiency of micropollutants was high for substances with high logK ow , which enhance the adsorption and removal with sludge. Low removal was observed for substances with low logK ow and acidic characteristics, and for substances with stabilizing elements of the chemical structure. Facilities that use activated sludge processes removed hormones more efficiently than facilities using trickling filter treatment technique. Moreover, longer hydraulic retention time increased the removal of pharmaceuticals, hormones, turbidity and total nitrogen. Removal of Caffeine, Ibuprofen, Estrone, Naproxen and Estradiol

  8. Stimulus Similarity and Encoding Time Influence Incidental Recognition Memory in Adult Monkeys with Selective Hippocampal Lesions

    Science.gov (United States)

    Zeamer, Alyson; Meunier, Martine; Bachevalier, Jocelyne

    2011-01-01

    Recognition memory impairment after selective hippocampal lesions in monkeys is more profound when measured with visual paired-comparison (VPC) than with delayed nonmatching-to-sample (DNMS). To clarify this issue, we assessed the impact of stimuli similarity and encoding duration on the VPC performance in monkeys with hippocampal lesions and…

  9. Families of birth-death processes with similar time-dependent behaviour.

    NARCIS (Netherlands)

    Lenin, R.B.; Parthasarathy, P.R.; Scheinhardt, Willem R.W.; van Doorn, Erik A.

    2000-01-01

    We consider birth-death processes taking values in N ≡ {0,1,... }, but allow the death rate in state 0 to be positive, so that escape from N is possible. Two such processes with transition functions { pij(t) } and { ̃pij(t) } are said to be similar if, for all i, j ∈ N, there are constants cij such

  10. Organic acid formation in steam–water cycles: Influence of temperature, retention time, heating rate and O2

    International Nuclear Information System (INIS)

    Moed, D.H.; Verliefde, A.R.D.; Heijman, S.G.J.; Rietveld, L.C.

    2014-01-01

    Organic carbon breaks down in boilers by hydrothermolysis, leading to the formation of organic acid anions, which are suspected to cause corrosion of steam–water cycle components. Prediction of the identity and quantity of these anions, based on feedwater organic carbon concentrations, has not been attempted, making it hard to establish a well-founded organic carbon guideline. By using a batch-reactor and flow reactor, the influence of temperature (276–352 °C), retention time (1–25 min), concentration (150–2400 ppb) and an oxygen scavenger (carbohydrazide) on organic acid anion formation from organic carbon was investigated. By comparing this to data gathered at a case-study site, the validity of setups was tested as well. The flow reactor provided results more representative for steam–water cycles than the batch reactor. It was found that lower heating rates give more organic acid anions as degradation products of organic carbon, both in quantity and species variety. The thermal stability of the organic acid anions is key. As boiler temperature increases, acetate becomes the dominant degradation product, due to its thermal stability. Shorter retention times lead to more variety and quantity of organic acid anions, due to a lack of time for the thermally less stable ones to degrade. Reducing conditions (or the absence of oxygen) increase the thermal stability of organic acid anions. As the feedwater organic carbon concentration decreases, there are relatively more organic acid anions formed. - Highlights: •Formation of organic acids from hydrothermolysis of organic carbon has been investigated. •The lower the temperature, the higher the variety of organic acid anions. •At the higher tested temperatures (331–352 °C) acetate is the dominant degradation product. •At longer retention times acetate is the dominant degradation product. •There is no linear relation between the organic carbon concentration and formed organic acids

  11. Effect of hydraulic retention time on hydrodynamic behavior of anaerobic-aerobic fixed bed reactor treating cattle slaughterhouse effluent

    Directory of Open Access Journals (Sweden)

    Daiane Cristina de Freitas

    2017-09-01

    Full Text Available The study of the hydrodynamic behavior in reactors provides characteristics of the flow regime and its anomalies that can reduce biological processes efficiency due to the decrease of the useful volume and the hydraulic retention time required for the performance of microbial activity. In this study, the hydrodynamic behavior of an anaerobic-aerobic fixed bed reactor, operated with HRT (hydraulic retention time of 24, 18 and 12 hours, was evaluated in the treatment of raw cattle slaughterhouse wastewater. Polyurethane foam and expanded clay were used as support media for biomass immobilization. Experimental data of pulse type stimulus-response assays were performed with eosin Y and bromophenol blue, and adjusted to the single-parameter theoretical models of dispersion and N-continuous stirred tank reactors in series (N-CSTR. N-CSTR model presented the best adjustment for the HRT and tracers evaluated. RDT (residence time distribution curves obtained with N-CSTR model in the assays with bromophenol blue resulted in better adjustment compared to the eosin Y. The predominant flow regime in AAFBR (anaerobic aerobic fixed bed reactor is the N-CSTR in series, as well as the existence of preferential paths and hydraulic short-circuiting.

  12. Biocompatible KMnF3 nanoparticular contrast agent with proper plasma retention time for in vivo magnetic resonance imaging.

    Science.gov (United States)

    Liu, Zhi-jun; Song, Xiao-xia; Xu, Xian-zhu; Tang, Qun

    2014-04-18

    Nanoparticular MRI contrast agents are rapidly becoming suitable for use in clinical diagnosis. An ideal nanoparticular contrast agent should be endowed with high relaxivity, biocompatibility, proper plasma retention time, and tissue-specific or tumor-targeting imaging. Herein we introduce PEGylated KMnF3 nanoparticles as a new type of T1 contrast agent. Studies showed that the nanoparticular contrast agent revealed high bio-stability with bovine serum albumin in PBS buffer solution, and presented excellent biocompatibility (low cytotoxicity, undetectable hemolysis and hemagglutination). Meanwhile the new contrast agent possessed proper plasma retention time (circulation half-life t1/2 is approximately 2 h) in the body of the administrated mice. It can be delivered into brain vessels and maintained there for hours, and is mostly cleared from the body within 48 h, as demonstrated by time-resolved MRI and Mn-biodistribution analysis. Those distinguishing features make it suitable to obtain contrast-enhanced brain magnetic resonance angiography. Moreover, through the process of passive targeting delivery, the T1 contrast agent clearly illuminates a brain tumor (glioma) with high contrast image and defined shape. This study demonstrates that PEGylated KMnF3 nanoparticles represent a promising biocompatible vascular contrast agent for magnetic resonance angiography and can potentially be further developed into an active targeted tumor MRI contrast agent.

  13. PROCAL: A Set of 40 Peptide Standards for Retention Time Indexing, Column Performance Monitoring, and Collision Energy Calibration.

    Science.gov (United States)

    Zolg, Daniel Paul; Wilhelm, Mathias; Yu, Peng; Knaute, Tobias; Zerweck, Johannes; Wenschuh, Holger; Reimer, Ulf; Schnatbaum, Karsten; Kuster, Bernhard

    2017-11-01

    Beyond specific applications, such as the relative or absolute quantification of peptides in targeted proteomic experiments, synthetic spike-in peptides are not yet systematically used as internal standards in bottom-up proteomics. A number of retention time standards have been reported that enable chromatographic aligning of multiple LC-MS/MS experiments. However, only few peptides are typically included in such sets limiting the analytical parameters that can be monitored. Here, we describe PROCAL (ProteomeTools Calibration Standard), a set of 40 synthetic peptides that span the entire hydrophobicity range of tryptic digests, enabling not only accurate determination of retention time indices but also monitoring of chromatographic separation performance over time. The fragmentation characteristics of the peptides can also be used to calibrate and compare collision energies between mass spectrometers. The sequences of all selected peptides do not occur in any natural protein, thus eliminating the need for stable isotope labeling. We anticipate that this set of peptides will be useful for multiple purposes in individual laboratories but also aiding the transfer of data acquisition and analysis methods between laboratories, notably the use of spectral libraries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. On the Relationship Between Transfer Function-derived Response Times and Hydrograph Analysis Timing Parameters: Are there Similarities?

    Science.gov (United States)

    Bansah, S.; Ali, G.; Haque, M. A.; Tang, V.

    2017-12-01

    The proportion of precipitation that becomes streamflow is a function of internal catchment characteristics - which include geology, landscape characteristics and vegetation - and influence overall storage dynamics. The timing and quantity of water discharged by a catchment are indeed embedded in event hydrographs. Event hydrograph timing parameters, such as the response lag and time of concentration, are important descriptors of how long it takes the catchment to respond to input precipitation and how long it takes the latter to filter through the catchment. However, the extent to which hydrograph timing parameters relate to average response times derived from fitting transfer functions to annual hydrographs is unknown. In this study, we used a gamma transfer function to determine catchment average response times as well as event-specific hydrograph parameters across a network of eight nested watersheds ranging from 0.19 km2 to 74.6 km2 prairie catchments located in south central Manitoba (Canada). Various statistical analyses were then performed to correlate average response times - estimated using the parameters of the fitted gamma transfer function - to event-specific hydrograph parameters. Preliminary results show significant interannual variations in response times and hydrograph timing parameters: the former were in the order of a few hours to days, while the latter ranged from a few days to weeks. Some statistically significant relationships were detected between response times and event-specific hydrograph parameters. Future analyses will involve the comparison of statistical distributions of event-specific hydrograph parameters with that of runoff response times and baseflow transit times in order to quantity catchment storage dynamics across a range of temporal scales.

  15. Combining similarity in time and space for training set formation under concept drift

    NARCIS (Netherlands)

    Zliobaite, I.

    2011-01-01

    Concept drift is a challenge in supervised learning for sequential data. It describes a phenomenon when the data distributions change over time. In such a case accuracy of a classifier benefits from the selective sampling for training. We develop a method for training set selection, particularly

  16. Fast Diffusion to Self-Similarity: Complete Spectrum, Long-Time Asymptotics, and Numerology

    Science.gov (United States)

    Denzler, Jochen; McCann, Robert J.

    2005-03-01

    The complete spectrum is determined for the operator on the Sobolev space W1,2ρ(Rn) formed by closing the smooth functions of compact support with respect to the norm Here the Barenblatt profile ρ is the stationary attractor of the rescaled diffusion equation in the fast, supercritical regime m the same diffusion dynamics represent the steepest descent down an entropy E(u) on probability measures with respect to the Wasserstein distance d2. Formally, the operator H=HessρE is the Hessian of this entropy at its minimum ρ, so the spectral gap H≧α:=2-n(1-m) found below suggests the sharp rate of asymptotic convergence: from any centered initial data 0≦u(0,x) ∈ L1(Rn) with second moments. This bound improves various results in the literature, and suggests the conjecture that the self-similar solution u(t,x)=R(t)-nρ(x/R(t)) is always slowest to converge. The higher eigenfunctions which are polynomials with hypergeometric radial parts and the presence of continuous spectrum yield additional insight into the relations between symmetries of Rn and the flow. Thus the rate of convergence can be improved if we are willing to replace the distance to ρ with the distance to its nearest mass-preserving dilation (or still better, affine image). The strange numerology of the spectrum is explained in terms of the number of moments of ρ.

  17. Classification of chilli sauces: Multivariate pattern recognition using selected GCMS retention time peaks of chilli sauces samples

    International Nuclear Information System (INIS)

    Low, Kah Hin; Sharifuddin Mohd Zain; Mohd Radzi Abas

    2008-01-01

    As a preliminary work on the possibility of separating classes of chili sauces based on taste or customer preferences, organic compounds from different kinds of chili sauces of various brands were separated and analyzed by gas chromatography/ mass spectrometry (GC/ MS). It was found that these organic compounds do form a basis for separation of different types of sauces. The similarity and dissimilarity of chromatograms due to the organic composition of the chili sauces were explored by multivariate pattern recognition techniques based on cluster analysis (CA) and principal component analysis (PCA). Both CA and PCA results exhibit four linearly separable classes, namely general sauces, hot sauces, sauces with benzoic acid and sauces with garlic. It was concluded that by using chosen retention peaks in the chromatograms of various sauce samples as multivariate features, CA and PCA can be successfully used to reveal the natural clusters existing in chili sauces according to their organic composition. (author)

  18. Puerarin exhibits greater distribution and longer retention time in neurons than astrocytes in a co-cultured system

    Directory of Open Access Journals (Sweden)

    Shu-Yong Wei

    2015-01-01

    Full Text Available The phytoestrogen puerarin has been shown to protect neurons and astrocytes in the brain, and is therefore an attractive drug in the treatment of Alzheimer′s disease, Parkinson′s disease and cerebral ischemia. Whether puerarin exhibits the same biological processes in neurons and astrocytes in vitro has rarely been reported. In this study, cortical neurons and astrocytes of newborn Sprague-Dawley rats were separated, identified and co-cultured in a system based on Transwell membranes. The retention time and distribution of puerarin in each cell type was detected by fluorescence spectrophotometry and fluorescence microscope. The concentration of puerarin in both co-cultured and separately cultured neurons was greater than that of astrocytes. Puerarin concentration reached a maximum 20 minutes after it was added. At 60 minutes after its addition, a scant amount of drug was detected in astrocytes; however in both separately cultured and co-cultured neurons, the concentration of puerarin achieved a stable level of about 12.8 ng/mL. The results indicate that puerarin had a higher concentration and longer retention time in neurons than that observed in astrocytes.

  19. A study of the predictive model on the user reaction time using the information amount and its similarity

    International Nuclear Information System (INIS)

    Lee, Sung Jin; Heo, Gyun Young; Chang, Soon Heung

    2004-01-01

    There are lots of studies on the user interface evaluation since it started. Recent studies focus on the contextual information of the user interface. We knew that the user reaction time increases as the amount of information increases. But, the relation between the contextual information and the user reaction time may be unknown. In this study, we proposed the similarity as one of the contextual information. We can expect that the similarity decreases the user reaction time. The goal of this study is to find some correlation about the user reaction time with both the information amount and the similarity. The experiment was performed with 20 participants. The results of experiment demonstrated our proposals

  20. Using just-in-time teaching and peer instruction in a residency program's core curriculum: enhancing satisfaction, engagement, and retention.

    Science.gov (United States)

    Schuller, Mary C; DaRosa, Debra A; Crandall, Marie L

    2015-03-01

    To assess use of the combined just-in-time teaching (JiTT) and peer instruction (PI) instructional strategy in a residency program's core curriculum. In 2010-2011, JiTT/PI was piloted in 31 core curriculum sessions taught by 22 faculty in the Northwestern University Feinberg School of Medicine's general surgery residency program. JiTT/PI required preliminary and categorical residents (n=31) to complete Web-based study questions before weekly specialty topic sessions. Responses were examined by faculty members "just in time" to tailor session content to residents' learning needs. In the sessions, residents answered multiple-choice questions (MCQs) using clickers and engaged in PI. Participants completed surveys assessing their perceptions of JiTT/PI. Videos were coded to assess resident engagement time in JiTT/PI sessions versus prior lecture-based sessions. Responses to topic session MCQs repeated in review sessions were evaluated to study retention. More than 70% of resident survey respondents indicated that JiTT/PI aided in the learning of key points. At least 90% of faculty survey respondents reported positive perceptions of aspects of the JiTT/PI strategy. Resident engagement time for JiTT/PI sessions was significantly greater than for prior lecture-based sessions (z=-2.4, P=.016). Significantly more review session MCQ responses were correct for residents who had attended corresponding JiTT/PI sessions than for residents who had not (chi-square=13.7; df=1; P<.001). JiTT/PI increased learner participation, learner retention, and the amount of learner-centered time. JiTT/PI represents an effective approach for meaningful and active learning in core curriculum sessions.

  1. The dynamics of single protein molecules is non-equilibrium and self-similar over thirteen decades in time

    Science.gov (United States)

    Hu, Xiaohu; Hong, Liang; Dean Smith, Micholas; Neusius, Thomas; Cheng, Xiaolin; Smith, Jeremy C.

    2016-02-01

    Internal motions of proteins are essential to their function. The time dependence of protein structural fluctuations is highly complex, manifesting subdiffusive, non-exponential behaviour with effective relaxation times existing over many decades in time, from ps up to ~102 s (refs ,,,). Here, using molecular dynamics simulations, we show that, on timescales from 10-12 to 10-5 s, motions in single proteins are self-similar, non-equilibrium and exhibit ageing. The characteristic relaxation time for a distance fluctuation, such as inter-domain motion, is observation-time-dependent, increasing in a simple, power-law fashion, arising from the fractal nature of the topology and geometry of the energy landscape explored. Diffusion over the energy landscape follows a non-ergodic continuous time random walk. Comparison with single-molecule experiments suggests that the non-equilibrium self-similar dynamical behaviour persists up to timescales approaching the in vivo lifespan of individual protein molecules.

  2. Similarity solutions of reaction–diffusion equation with space- and time-dependent diffusion and reaction terms

    Energy Technology Data Exchange (ETDEWEB)

    Ho, C.-L. [Department of Physics, Tamkang University, Tamsui 25137, Taiwan (China); Lee, C.-C., E-mail: chieh.no27@gmail.com [Center of General Education, Aletheia University, Tamsui 25103, Taiwan (China)

    2016-01-15

    We consider solvability of the generalized reaction–diffusion equation with both space- and time-dependent diffusion and reaction terms by means of the similarity method. By introducing the similarity variable, the reaction–diffusion equation is reduced to an ordinary differential equation. Matching the resulting ordinary differential equation with known exactly solvable equations, one can obtain corresponding exactly solvable reaction–diffusion systems. Several representative examples of exactly solvable reaction–diffusion equations are presented.

  3. Working with a fixed operating room team on consecutive similar cases and the effect on case duration and turnover time.

    Science.gov (United States)

    Stepaniak, Pieter S; Vrijland, Wietske W; de Quelerij, Marcel; de Vries, Guus; Heij, Christiaan

    2010-12-01

    If variation in procedure times could be controlled or better predicted, the cost of surgeries could be reduced through improved scheduling of surgical resources. This study on the impact of similar consecutive cases on the turnover, surgical, and procedure times tests the perception that repeating the same manual tasks reduces the duration of these tasks. We hypothesize that when a fixed team works on similar consecutive cases the result will be shorter turnover and procedure duration as well as less variation as compared with the situation without a fixed team. Case-control study. St Franciscus Hospital, a large general teaching hospital in Rotterdam, the Netherlands. Two procedures, inguinal hernia repair and laparoscopic cholecystectomy, were selected and divided across a control group and a study group. Patients were randomly assigned to the study or control group. Preparation time, surgical time, procedure time, and turnover time. For inguinal hernia repair, we found a significantly lower preparation time and 10 minutes less procedure time in the study group, as compared with the control group. Variation in the study group was lower, as compared with the control group. For laparoscopic cholecystectomy, preparation time was significantly lower in the study group, as compared with the control group. For both procedures, there was a significant decrease in turnover time. Scheduling similar consecutive cases and performing with a fixed team results in lower turnover times and preparation times. The procedure time of the inguinal hernia repair decreased significantly and has practical scheduling implications. For more complex surgery, like laparoscopic cholecystectomy, there is no effect on procedure time.

  4. Critical evaluation of a simple retention time predictor based on LogKow as a complementary tool in the identification of emerging contaminants in water.

    Science.gov (United States)

    Bade, Richard; Bijlsma, Lubertus; Sancho, Juan V; Hernández, Felix

    2015-07-01

    There has been great interest in environmental analytical chemistry in developing screening methods based on liquid chromatography-high resolution mass spectrometry (LC-HRMS) for emerging contaminants. Using HRMS, compound identification relies on the high mass resolving power and mass accuracy attainable by these analyzers. When dealing with wide-scope screening, retention time prediction can be a complementary tool for the identification of compounds, and can also reduce tedious data processing when several peaks appear in the extracted ion chromatograms. There are many in silico, Quantitative Structure-Retention Relationship methods available for the prediction of retention time for LC. However, most of these methods use commercial software to predict retention time based on various molecular descriptors. This paper explores the applicability and makes a critical discussion on a far simpler and cheaper approach to predict retention times by using LogKow. The predictor was based on a database of 595 compounds, their respective LogKow values and a chromatographic run time of 18min. Approximately 95% of the compounds were found within 4.0min of their actual retention times, and 70% within 2.0min. A predictor based purely on pesticides was also made, enabling 80% of these compounds to be found within 2.0min of their actual retention times. To demonstrate the utility of the predictors, they were successfully used as an additional tool in the identification of 30 commonly found emerging contaminants in water. Furthermore, a comparison was made by using different mass extraction windows to minimize the number of false positives obtained. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Recovery of resources for advanced life support space applications: effect of retention time on biodegradation of two crop residues in a fed-batch, continuous stirred tank reactor

    Science.gov (United States)

    Strayer, R. F.; Finger, B. W.; Alazraki, M. P.; Cook, K.; Garland, J. L.

    2002-01-01

    Bioreactor retention time is a key process variable that will influence costs that are relevant to long distance space travel or long duration space habitation. However. little is known about the effects of this parameter on the microbiological treatment options that are being proposed for Advanced Life Support (ALS) systems. Two bioreactor studies were designed to examine this variable. In the first one, six retention times ranging from 1.3 to 21.3 days--were run in duplicate, 81 working-volume continuous stirred tank reactors (CSTR) that were fed ALS wheat residues. Ash-free dry weight loss, carbon mineralization, soluble TOC reduction, changes in fiber content (cellulose, hemicellulose, and lignin), bacterial numbers, and mineral recoveries were monitored. At short retention times--1.33 days--biodegradation was poor (total: 16-20%, cellulose - 12%, hemicellulose - 28%) but soluble TOC was decreased by 75-80% and recovery of major crop inorganic nutrients was adequate, except for phosphorus. A high proportion of the total bacteria (ca. 83%) was actively respiring. At the longest retention time tested, 21.3 days, biodegradation was good (total: 55-60%, cellulose ca. 70%, hemicellulose - ca. 55%) and soluble TOC was decreased by 80%. Recovery of major nutrients, except phosphorus, remained adequate. A very low proportion of total bacteria was actively respiring (ca. 16%). The second bioreactor study used potato residue to determine if even shorter retention times could be used (range 0.25-2.0 days). Although overall biodegradation deteriorated, the degradation of soluble TOC continued to be ca. 75%. We conclude that if the goal of ALS bioprocessing is maximal degradation of crop residues, including cellulose, then retention times of 10 days or longer will be needed. If the goal is to provide inorganic nutrients with the smallest volume/weight bioreactor possible, then a retention time of 1 day (or less) is sufficient.

  6. Effect of dietary coarsely ground corn on broiler live performance, gastrointestinal tract development, apparent ileal digestibility of energy and nitrogen, and digesta particle size distribution and retention time.

    Science.gov (United States)

    Xu, Y; Stark, C R; Ferket, P R; Williams, C M; Pacheco, W J; Brake, J

    2015-01-01

    Dietary structural material has been reported to improve broiler live performance and gastrointestinal tract (GIT) function. In this 50 d cage study, the effects of coarsely ground corn (CC) inclusion on broiler live performance, GIT development, apparent ileal digestibility (AID) of energy and nitrogen (N), and digesta particle size distribution and retention time were investigated. This study included 3 CC inclusions (0, 25, and 50% fine corn [FC] replaced by CC), with 6 replicate cages of 10 birds per treatment. The feed conversion ratio (FCR) at 35 and 42 d was improved (P<0.01) as the dietary inclusion of CC increased without effect on feed intake. The 50% CC diet increased absolute and relative gizzard weight at 42 d of age as compared to diets with 0 and 25% CC (P<0.01). Dietary CC increased absolute proventriculus weight at 28 d of age (P<0.05). A numerically lower gizzard digesta pH (P<0.08) was observed at 28 d but not 42 d of age, and there was no difference in proventriculus, jejunum, or ileum digesta pH at 28 or 42 d of age. The 25 and 50% CC treatments increased the digesta retention time at 30 and 45 d of age (P<0.05 and P<0.01, respectively). The 25 and 50% CC treatments improved AID of energy by 7.1 and 8.2%, respectively, when compared with the 0% CC treatment, and they improved AID of N by 12.2 and 12.4%, respectively (P<0.01). The digesta particles in the jejunum exhibited a similar distribution, with a dgw (geometric mean diameter by mass) of 218, 204, and 181 μm when 0, 25, of 50% CC diets were consumed, respectively. In conclusion, birds fed pelleted and screened diets that contained 25 and 50% CC exhibited increased BW, improved FCR, and increased AID of energy and N, which was probably due to enhanced gizzard development and greater digesta retention time. © The Author 2015. Published by Oxford University Press on behalf of Poultry Science Association.

  7. Determination of n-octanol/water partition coefficient for DDT-related compounds by RP-HPLC with a novel dual-point retention time correction.

    Science.gov (United States)

    Han, Shu-ying; Qiao, Jun-qin; Zhang, Yun-yang; Yang, Li-li; Lian, Hong-zhen; Ge, Xin; Chen, Hong-yuan

    2011-03-01

    n-Octanol/water partition coefficients (P) for DDTs and dicofol were determined by reversed-phase high performance liquid chromatography (RP-HPLC) on a C(18) column using methanol-water mixture as mobile phase. A dual-point retention time correction (DP-RTC) was proposed to rectify chromatographic retention time (t(R)) shift resulted from stationary phase aging. Based on this correction, the relationship between logP and logk(w), the logarithm of the retention factor extrapolated to pure water, was investigated for a set of 12 benzene homologues and DDT-related compounds with reliable experimental P as model compounds. A linear regression logP=(1.10±0.04) logk(w) - (0.60±0.17) was established with correlation coefficient R(2) of 0.988, cross-validated correlation coefficient R(cv)(2) of 0.983 and standard deviation (SD) of 0.156. This model was further validated using four verification compounds, naphthalene, biphenyl, 2,2-bis(4-chlorophenyl)-1,1-dichloroethane (p,p'-DDD) and 2,2-bis(4-chlorophenyl)-1,1-dichloroethene (p,p'-DDE) with similar structure to DDT. The RP-HPLC-determined P values showed good consistency with shake-flask (SFM) or slow-stirring (SSM) results, especially for highly hydrophobic compounds with logP in the range of 4-7. Then, the P values for five DDT-related compounds, 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1,1-trichloroethane (o,p'-DDT), 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1-dichloroethane (o,p'-DDD), 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1-dichloroethene (o,p'-DDE), and 2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol (dicofol) and its main degradation product 4,4'-dichlorobenzophenone (p,p'-DBP) were evaluated by the improved RP-HPLC method for the first time. The excellent precision with SD less than 0.03 proved that the novel DP-RTC protocol can significantly increases the determination accuracy and reliability of P by RP-HPLC. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. [Effect of different sludge retention time (SRT) on municipal sewage sludge bioleaching continuous plug flow reaction system].

    Science.gov (United States)

    Liu, Fen-Wu; Zhou, Li-Xiang; Zhou, Jun; Jiang, Feng; Wang, Dian-Zhan

    2012-01-01

    A plug-flow bio-reactor of 700 L working volume for sludge bioleaching was used in this study. The reactor was divided into six sections along the direction of the sludge movement. Fourteen days of continuous operation of sludge bioleaching with different sludge retention time (SRT) under the condition of 1.2 m3 x h(-1) aeration amount and 4 g x L(-1) of microbial nutritional substance was conducted. During sludge bioleaching, the dynamic changes of pH, DO, dewaterability (specific resistance to filtration, SRF) of sewage sludge in different sections were investigated in the present study. The results showed that sludge pH were maintained at 5.00, 3.00, 2.90, 2.70, 2.60 and 2.40 from section 1 to section 6 and the SRF of sludge was drastically decreased from initial 0.64 x 10(13) m x kg(-1) to the final 0.33 x 10(13) m x kg(-1) when bioleaching system reached stable at hour 72 with SRT 2.5d. In addition, the sludge pH were maintained at 5.10, 4.10, 3.20, 2.90, 2.70 and 2.60, the DO value were 0.43, 1.47, 3.29, 4.76, 5.75 and 5.88 mg x L(-1) from section 1 to section 6, and the SRF of sludge was drastically decreased from initial 0.56 x 10(13) to the final 0.20 x 10(13) m x kg(-1) when bioleaching system reached stable at hour 120 with SRT 2 d. The pH value was increased to 3.00 at section 6 at hour 48 h with SRT 1.25 d. The bioleaching system imbalanced in this operation conditions because of the utilization efficiency of microbial nutritional substance by Acidibacillus spp. was decreased. The longer sludge retention time, the easier bioleaching system reached stable. 2 d could be used as the optimum sludge retention time in engineering application. The bioleached sludge was collected and dewatered by plate-and-frame filter press to the moisture content of dewatered sludge cake under 60%. This study would provide the necessary data to the engineering application on municipal sewage sludge bioleaching.

  9. A study on the quantitative model of human response time using the amount and the similarity of information

    International Nuclear Information System (INIS)

    Lee, Sung Jin

    2006-02-01

    The mental capacity to retain or recall information, or memory is related to human performance during processing of information. Although a large number of studies have been carried out on human performance, little is known about the similarity effect. The purpose of this study was to propose and validate a quantitative and predictive model on human response time in the user interface with the basic concepts of information amount, similarity and degree of practice. It was difficult to explain human performance by only similarity or information amount. There were two difficulties: constructing a quantitative model on human response time and validating the proposed model by experimental work. A quantitative model based on the Hick's law, the law of practice and similarity theory was developed. The model was validated under various experimental conditions by measuring the participants' response time in the environment of a computer-based display. Human performance was improved by degree of similarity and practice in the user interface. Also we found the age-related human performance which was degraded as he or she was more elder. The proposed model may be useful for training operators who will handle some interfaces and predicting human performance by changing system design

  10. Influence of solids retention time on membrane fouling: characterization of extracellular polymeric substances and soluble microbial products.

    Science.gov (United States)

    Duan, Liang; Tian, Zhiyong; Song, Yonghui; Jiang, Wei; Tian, Yuan; Li, Shan

    2015-01-01

    The objective of this study was to investigate the influence of solids retention time (SRT) on membrane fouling and the characteristics of biomacromolecules. Four identical laboratory-scale membrane bioreactors (MBRs) were operated with SRTs for 10, 20, 40 and 80 days. The results indicated that membrane fouling occurred faster and more readily under short SRTs. Fouling resistance was the primary source of filtration resistance. The modified fouling index (MFI) results suggested that the more ready fouling at short SRTs could be attributed to higher concentrations of soluble microbial products (SMP). Fourier transform infrared (FTIR) spectra indicated that the SRT had a weak influence on the functional groups of the total extracellular polymeric substances (TEPS) and SMP. However, the MBR under a short SRT had more low-molecular-weight (MW) compounds (100 kDa). Aromatic protein and tryptophan protein-like substances were the dominant groups in the TEPS and SMP, respectively.

  11. Photo-fermentative hydrogen production in a 4m3 baffled reactor: Effects of hydraulic retention time.

    Science.gov (United States)

    Zhang, Quanguo; Lu, Chaoyang; Lee, Duu-Jong; Lee, Yu-Jen; Zhang, Zhiping; Zhou, Xuehua; Hu, Jianjun; Wang, Yi; Jiang, Danping; He, Chao; Zhang, Tian

    2017-09-01

    A 4m 3 pilot-scale baffled continuous-flow photoreactor with four sequential chambers (#1-#4) was established and tested to evaluate its photo-fermentative hydrogen production from wastewater that contains (10g/L glucose using a functional consortium at 30°C, under light with an intensity of 3000±200lux with a hydraulic retention time (HRT) of 24-72h. The hydrogen production rate and the broth characteristics varied significantly in the flow direction. The hydrogen production rate was highest in chamber #1, and lower in chambers #2-#4 at an HRT of 72h, while the peak production rate shifted to the latter chambers as the HRT was shortened. The overall H 2 production rate increased as HRT decreased, but was not consistent with the predictions that were based on the complete-mixing assumption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Diversity and dynamics of dominant and rare bacterial taxa in replicate sequencing batch reactors operated under different solids retention time

    KAUST Repository

    Bagchi, Samik

    2014-10-19

    In this study, 16S rRNA gene pyrosequencing was applied in order to provide a better insight on the diversity and dynamics of total, dominant, and rare bacterial taxa in replicate lab-scale sequencing batch reactors (SBRs) operated at different solids retention time (SRT). Rank-abundance curves showed few dominant operational taxonomic units (OTUs) and a long tail of rare OTUs in all reactors. Results revealed that there was no detectable effect of SRT (2 vs. 10 days) on Shannon diversity index and OTU richness of both dominant and rare taxa. Nonmetric multidimensional scaling analysis showed that the total, dominant, and rare bacterial taxa were highly dynamic during the entire period of stable reactor performance. Also, the rare taxa were more dynamic than the dominant taxa despite expected low invasion rates because of the use of sterile synthetic media.

  13. Anaerobic co-digestion of swine manure and crude glycerol derived from animal fat - Effect of hydraulic retention time

    DEFF Research Database (Denmark)

    Lymperatou, Anna; Skiadas, Ioannis V.; Gavala, Hariklia N.

    2018-01-01

    Crude glycerol (CG), an abundant by-product of bio-diesel production, has been identified as a suitable co-substrate for improving the biogas production of livestock manure through anaerobic digestion (AD). In this study, the potential of utilizing CG generated from the esterification of animal......, biochemical methane potential tests indicated that the addition of 1% w/w CG to swine manure-AD is more efficient in terms of percent of theoretical amount of methane obtained than the addition of 3% w/w. However, in continuous experiments, co-digestion of manure with 3% w/w CG did not exhibit any sign...... fats for biogas production was studied in both batch and continuous AD experiments, with emphasis on the importance of the hydraulic retention time (HRT). Batch experiments showed that the limiting step in the methane production rate during CG mono-digestion was the 1,3-propanediol uptake. Additionally...

  14. First-time whole blood donation: A critical step for donor safety and retention on first three donations.

    Science.gov (United States)

    Gillet, P; Rapaille, A; Benoît, A; Ceinos, M; Bertrand, O; de Bouyalsky, I; Govaerts, B; Lambermont, M

    2015-01-01

    Whole blood donation is generally safe although vasovagal reactions can occur (approximately 1%). Risk factors are well known and prevention measures are shown as efficient. This study evaluates the impact of the donor's retention in relation to the occurrence of vasovagal reaction for the first three blood donations. Our study of data collected over three years evaluated the impact of classical risk factors and provided a model including the best combination of covariates predicting VVR. The impact of a reaction at first donation on return rate and complication until the third donation was evaluated. Our data (523,471 donations) confirmed the classical risk factors (gender, age, donor status and relative blood volume). After stepwise variable selection, donor status, relative blood volume and their interaction were the only remaining covariates in the model. Of 33,279 first-time donors monitored over a period of at least 15 months, the first three donations were followed. Data emphasised the impact of complication at first donation. The return rate for a second donation was reduced and the risk of vasovagal reaction was increased at least until the third donation. First-time donation is a crucial step in the donors' career. Donors who experienced a reaction at their first donation have a lower return rate for a second donation and a higher risk of vasovagal reaction at least until the third donation. Prevention measures have to be processed to improve donor retention and provide blood banks with adequate blood supply. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  15. Low ambient temperature elevates plasma triiodothyronine concentrations while reducing digesta mean retention time and methane yield in sheep.

    Science.gov (United States)

    Barnett, M C; McFarlane, J R; Hegarty, R S

    2015-06-01

    Ruminant methane yield (MY) is positively correlated with mean retention time (MRT) of digesta. The hormone triiodothyronine (T3 ), which is negatively correlated with ambient temperature, is known to influence MRT. It was hypothesised that exposing sheep to low ambient temperatures would increase plasma T3 concentration and decrease MRT of digesta within the rumen of sheep, resulting in a reduction of MY. To test this hypothesis, six Merino sheep were exposed to two different ambient temperatures (cold treatment, 9 ± 1 °C; warm control 26 ± 1 °C). The effects on MY, digesta MRT, plasma T3 concentration, CO2 production, DM intake, DM digestibility, change in body weight (BW), rumen volatile fatty acid (VFA) concentrations, estimated microbial protein output, protozoa abundance, wool growth, water intake, urine output and rectal temperature were studied. Cold treatment resulted in a reduction in MY (p < 0.01); digesta MRT in rumen (p < 0.01), hindgut (p = 0.01) and total digestive tract (p < 0.01); protozoa abundance (p < 0.05); and water intake (p < 0.001). Exposure to cold temperature increased plasma T3 concentration (p < 0.05), CO2 production (p = 0.01), total VFA concentrations (p = 0.03) and estimated microbial output from the rumen (p = 0.03). The rate of wool growth increased (p < 0.01) due to cold treatment, but DM intake, DM digestibility and BW change were not affected. The results suggest that exposure of sheep to cold ambient temperatures reduces digesta retention time in the gastrointestinal tract, leading to a reduction in enteric methane yield. Further research is warranted to determine whether T3 could be used as an indirect selection tool for genetic selection of low enteric methane-producing ruminants. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

  16. Behaviour of biopolymeric substances in the activated sludge of an MBR system working with high hydraulic retention time.

    Science.gov (United States)

    Marín, Eugenio; Pérez, Jorge I; Gómez, Miguel A

    2017-10-15

    This study was undertaken to analyse the activated sludge of a membrane bioreactor (MBR), the behaviour of extracellular polymeric substances (EPS) and soluble microbial products (SMP) as well as their biopolymers composition, in the activated sludge of a membrane bioreactor (MBR) and their influence on membrane fouling were analysed. For the experiment an experimental fullscale MBR working with real urban wastewater at high hydraulic retention time with a variable sludge-retention time (SRT) was used. The MBR system worked in denitrification/nitrification conformation at a constant flow rate (Q = 0.45 m 3 /h) with a recirculation flow rate of 4Q. The concentrations of SMP in the activated sludge were lower than the concentrations of EPS over the entire study, with humic substances being the main components of the two biopolymers. SMP and, more specifically, SMP carbohydrates, were the most influential biopolymers in membrane fouling, while for EPS and their components, no relation was found with fouling. The SRT and temperature were the operational variables that most influenced the SMP and EPS concentration, causing the increase of SRT and temperature a lower concentration in both biopolymers, although the effect was not the same for all the components, particularly for the EPS carbohydrates, which increased with longer SRTs. Both operational variables were also the ones most influential on the concentration of organic matter of the effluent, due to their effect on the SMP. The volatile suspended solid/total suspended solid (VSS/TSS) ratio in the activated sludge can be applied as a good indicator of the risk of membrane fouling by biopolymers in MBR systems.

  17. Short time-scale wind forced variability in the Río de la Plata Estuary and its role on ichthyoplankton retention

    Science.gov (United States)

    Simionato, C. G.; Berasategui, A.; Meccia, V. L.; Acha, M.; Mianzan, H.

    2008-01-01

    The Río de la Plata Estuary presents a strong bottom salinity front located over a submerged shoal. Apparently favored by retention processes, it is a spawning ground for several coastal fishes. This estuary is very shallow and essentially wind driven and, moreover, in time scales relevant to biota, estuarine circulation is wind dominated and highly variable. Two intriguing questions are, therefore, how this system can favor retention and what the involved mechanisms are. This paper qualitatively explores mechanisms involved in the estuary where retention is favored applying numerical simulations in which neutral particles - simulating fish eggs and early larvae - are released along the bottom frontal zone and tracked for different wind conditions. Results suggest that retentive features can be a consequence of estuarine response to natural wind variability acting over bathymetric features. For winds from most directions, particles either remain trapped near their launching position or move northeastward to southwestward along the shoal. As alternation of winds that favor along-shoal motion is the dominant feature of wind variability in the region, a retentive scenario results from prevailing wind variability. Additionally, winds that tend to export particles with a poor chance of being restored to the front are neither frequent nor persistent. Results show, therefore, that physical forcing alone might generate a retentive scenario at the inner part of this estuary. The physical retention mechanism is more effective for bottom than for surface launched particles. Wind statistics indicate that the proposed mechanism has different implications for retention along the seasons. Spring is the most favorable season, followed by summer, when particles would have a larger propensity to reach the southern area of the estuary (Samborombón Bay). Fall and winter are increasingly less favorable. All these features are consistent with patterns observed in the region in

  18. Effects of Feedback Frequency and Timing on Acquisition, Retention, and Transfer of Speech Skills in Acquired Apraxia of Speech

    Science.gov (United States)

    Hula, Shannon N. Austermann; Robin, Donald A.; Maas, Edwin; Ballard, Kirrie J.; Schmidt, Richard A.

    2008-01-01

    Purpose: Two studies examined speech skill learning in persons with apraxia of speech (AOS). Motor-learning research shows that delaying or reducing the frequency of feedback promotes retention and transfer of skills. By contrast, immediate or frequent feedback promotes temporary performance enhancement but interferes with retention and transfer.…

  19. Improving Attendance and Retention in Out-of-School Time Programs. Research-to-Results Practitioner Insights. Publication # 2007-17

    Science.gov (United States)

    Kennedy, Elena; Wilson, Brooke; Valladares, Sherylls; Bronte-Tinkew, Jacinta

    2007-01-01

    Regular participation in out-of-school time activities is associated with benefits for children. However, children cannot reap the benefits of program participation if they do not attend programs in the first place. This brief focuses on ways in which out-of-school time programs can improve the attendance and retention of children and youth in…

  20. A study of the predictive model on the user reaction time using the information amount and similarity

    International Nuclear Information System (INIS)

    Lee, Sungjin; Heo, Gyunyoung; Chang, S.H.

    2004-01-01

    Human operations through a user interface are divided into two types. The one is the single operation that is performed on a static interface. The other is the sequential operation that achieves a goal by handling several displays through operator's navigation in the crt-based console. Sequential operation has similar meaning with continuous task. Most operations in recently developed computer applications correspond to the sequential operation, and the single operation can be considered as a part of the sequential operation. In the area of HCI (human computer interaction) evaluation, the Hick-Hyman law counts as the most powerful theory. The most important factor in the equation of Hick-Hyman law about choice reaction time is the quantified amount of information conveyed by a statement, stimulus, or event. Generally, we can expect that if there are some similarities between a series of interfaces, human operator is able to use his attention resource effectively. That is the performance of human operator is increased by the similarity. The similarity may be able to affect the allocation of attention resource based on separate STSS (short-term sensory store) and long-term memory. There are theories related with this concept, which are task switching paradigm and the law of practice. However, it is not easy to explain the human operator performance with only the similarity or the information amount. There are few theories to explain the performance with the combination of the similarity and the information amount. The objective of this paper is to purpose and validate the quantitative and predictive model on the user reaction time in CRT-based displays. Another objective is to validate various theories related with human cognition and perception, which are Hick-Hyman law and the law of practice as representative theories. (author)

  1. Extended local similarity analysis (eLSA) of microbial community and other time series data with replicates.

    Science.gov (United States)

    Xia, Li C; Steele, Joshua A; Cram, Jacob A; Cardon, Zoe G; Simmons, Sheri L; Vallino, Joseph J; Fuhrman, Jed A; Sun, Fengzhu

    2011-01-01

    The increasing availability of time series microbial community data from metagenomics and other molecular biological studies has enabled the analysis of large-scale microbial co-occurrence and association networks. Among the many analytical techniques available, the Local Similarity Analysis (LSA) method is unique in that it captures local and potentially time-delayed co-occurrence and association patterns in time series data that cannot otherwise be identified by ordinary correlation analysis. However LSA, as originally developed, does not consider time series data with replicates, which hinders the full exploitation of available information. With replicates, it is possible to understand the variability of local similarity (LS) score and to obtain its confidence interval. We extended our LSA technique to time series data with replicates and termed it extended LSA, or eLSA. Simulations showed the capability of eLSA to capture subinterval and time-delayed associations. We implemented the eLSA technique into an easy-to-use analytic software package. The software pipeline integrates data normalization, statistical correlation calculation, statistical significance evaluation, and association network construction steps. We applied the eLSA technique to microbial community and gene expression datasets, where unique time-dependent associations were identified. The extended LSA analysis technique was demonstrated to reveal statistically significant local and potentially time-delayed association patterns in replicated time series data beyond that of ordinary correlation analysis. These statistically significant associations can provide insights to the real dynamics of biological systems. The newly designed eLSA software efficiently streamlines the analysis and is freely available from the eLSA homepage, which can be accessed at http://meta.usc.edu/softs/lsa.

  2. A Study of Wavelet Analysis and Data Extraction from Second-Order Self-Similar Time Series

    Directory of Open Access Journals (Sweden)

    Leopoldo Estrada Vargas

    2013-01-01

    Full Text Available Statistical analysis and synthesis of self-similar discrete time signals are presented. The analysis equation is formally defined through a special family of basis functions of which the simplest case matches the Haar wavelet. The original discrete time series is synthesized without loss by a linear combination of the basis functions after some scaling, displacement, and phase shift. The decomposition is then used to synthesize a new second-order self-similar signal with a different Hurst index than the original. The components are also used to describe the behavior of the estimated mean and variance of self-similar discrete time series. It is shown that the sample mean, although it is unbiased, provides less information about the process mean as its Hurst index is higher. It is also demonstrated that the classical variance estimator is biased and that the widely accepted aggregated variance-based estimator of the Hurst index results biased not due to its nature (which is being unbiased and has minimal variance but to flaws in its implementation. Using the proposed decomposition, the correct estimation of the Variance Plot is described, as well as its close association with the popular Logscale Diagram.

  3. Effect of solids retention time and wastewater characteristics on biological phosphorus removal

    DEFF Research Database (Denmark)

    Henze, Mogens; Aspegren, H.; Jansen, J.l.C.

    2002-01-01

    with time which has importance in relation to modelling. The overall conclusion of the comparison between the two plants is that the biological phosphorus removal efficiency under practical operating conditions is affected by the SRT in the plant and the wastewater composition. Thus great care should......The paper deals with the effect of wastewater, plant design and operation in relation to biological nitrogen and phosphorus removal and the possibilities to model the processes. Two Bio-P pilot plants were operated for 2.5 years in parallel receiving identical wastewater. The plants had SRT of 4...... and 21 days, the latter had nitrification and denitrification. The plant with 4 days SRT had much more variable biomass characteristics, than the one with the high SRT. The internal storage compounds, PHA, were affected significantly by the concentration of fatty acids or other easily degradable organics...

  4. Mapping Rice Cropping Systems in Vietnam Using an NDVI-Based Time-Series Similarity Measurement Based on DTW Distance

    Directory of Open Access Journals (Sweden)

    Xudong Guan

    2016-01-01

    Full Text Available Normalized Difference Vegetation Index (NDVI derived from Moderate Resolution Imaging Spectroradiometer (MODIS time-series data has been widely used in the fields of crop and rice classification. The cloudy and rainy weather characteristics of the monsoon season greatly reduce the likelihood of obtaining high-quality optical remote sensing images. In addition, the diverse crop-planting system in Vietnam also hinders the comparison of NDVI among different crop stages. To address these problems, we apply a Dynamic Time Warping (DTW distance-based similarity measure approach and use the entire yearly NDVI time series to reduce the inaccuracy of classification using a single image. We first de-noise the NDVI time series using S-G filtering based on the TIMESAT software. Then, a standard NDVI time-series base for rice growth is established based on field survey data and Google Earth sample data. NDVI time-series data for each pixel are constructed and the DTW distance with the standard rice growth NDVI time series is calculated. Then, we apply thresholds to extract rice growth areas. A qualitative assessment using statistical data and a spatial assessment using sampled data from the rice-cropping map reveal a high mapping accuracy at the national scale between the statistical data, with the corresponding R2 being as high as 0.809; however, the mapped rice accuracy decreased at the provincial scale due to the reduced number of rice planting areas per province. An analysis of the results indicates that the 500-m resolution MODIS data are limited in terms of mapping scattered rice parcels. The results demonstrate that the DTW-based similarity measure of the NDVI time series can be effectively used to map large-area rice cropping systems with diverse cultivation processes.

  5. Ultrasonic sludge disintegration for enhanced methane production in anaerobic digestion: effects of sludge hydrolysis efficiency and hydraulic retention time.

    Science.gov (United States)

    Kim, Dong-Jin; Lee, Jonghak

    2012-01-01

    Hydrolysis of waste activated sludge (WAS) has been regarded as the rate limiting step of anaerobic sludge digestion. Therefore, in this study, the effect of ultrasound and hydraulic residence time during sludge hydrolysis was investigated with the goal of enhancing methane production from anaerobic digestion (AD). WAS was ultrasonically disintegrated for hydrolysis, and it was semi-continuously fed to an anaerobic digesters at various hydraulic retention times (HRTs). The results of these experiments showed that the solids and chemical oxygen demand (COD) removal efficiencies when using ultrasonically disintegrated sludge were higher during AD than the control sludge. The longer the HRT, the higher the removal efficiencies of solids and COD, while methane production increased with lower HRT. Sludge with 30% hydrolysis produced 7 × more methane production than the control sludge. The highest methane yields were 0.350 m(3)/kg volatile solids (VS)(add) and 0.301 m(3)/kg COD(con) for 16 and 30% hydrolyzed sludge, respectively. In addition, we found that excess ultrasound irradiation may inhibit AD since the 50% hydrolyzed sludge produced lower methane yields than 16 and 30% hydrolyzed sludge.

  6. Bioleaching of spent Ni-Cd batteries by continuous flow system: Effect of hydraulic retention time and process load

    International Nuclear Information System (INIS)

    Zhao Ling; Yang Dong; Zhu Nanwen

    2008-01-01

    Spent Ni-Cd batteries bring a severe environmental problem that needs to be solved urgently. A novel continuous flow two-step leaching system based on bioleaching was introduced to dissolve heavy metals in batteries. It consists of an acidifying reactor which was used to culture indigenous thiobacilli and a leaching reactor which was used to leach metals from spent batteries. The indigenous acidophilic thiobacilli in sewage sludge was used as the microorganisms and the sludge itself as culture medium. Bioleaching tests at different hydraulic retention time (HRT) and process load in the leaching reactor were performed. The results showed that the longer the HRT (1, 3, 6, 9 and 15 days) was, the more time required to achieve the complete leaching of Ni, Cd and Co. The maximum dissolution of cadmium and cobalt was achieved at higher pH values (3.0-4.5) while the leaching of nickel hydroxide and nickel in metallic form (Ni 0 ) were obtained separately in different acidity (pH 2.5-3.5). It cost about 25, 30 and more than 40 days to remove all of the three heavy metals with the process load of two, four and eight Ni-Cd batteries under the conditions that the ingoing bio-sulphuric acid was 1 L d -1 and HRT was 3 days

  7. Bioleaching of spent Ni-Cd batteries by continuous flow system: effect of hydraulic retention time and process load.

    Science.gov (United States)

    Zhao, Ling; Yang, Dong; Zhu, Nan-Wen

    2008-12-30

    Spent Ni-Cd batteries bring a severe environmental problem that needs to be solved urgently. A novel continuous flow two-step leaching system based on bioleaching was introduced to dissolve heavy metals in batteries. It consists of an acidifying reactor which was used to culture indigenous thiobacilli and a leaching reactor which was used to leach metals from spent batteries. The indigenous acidophilic thiobacilli in sewage sludge was used as the microorganisms and the sludge itself as culture medium. Bioleaching tests at different hydraulic retention time (HRT) and process load in the leaching reactor were performed. The results showed that the longer the HRT (1, 3, 6, 9 and 15 days) was, the more time required to achieve the complete leaching of Ni, Cd and Co. The maximum dissolution of cadmium and cobalt was achieved at higher pH values (3.0-4.5) while the leaching of nickel hydroxide and nickel in metallic form (Ni0) were obtained separately in different acidity (pH 2.5-3.5). It cost about 25, 30 and more than 40 days to remove all of the three heavy metals with the process load of two, four and eight Ni-Cd batteries under the conditions that the ingoing bio-sulphuric acid was 1Ld(-1) and HRT was 3 days.

  8. Bioleaching of spent Ni-Cd batteries by continuous flow system: Effect of hydraulic retention time and process load

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Ling; Yang Dong [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhu Nanwen [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)], E-mail: nwzhu@sina.com

    2008-12-30

    Spent Ni-Cd batteries bring a severe environmental problem that needs to be solved urgently. A novel continuous flow two-step leaching system based on bioleaching was introduced to dissolve heavy metals in batteries. It consists of an acidifying reactor which was used to culture indigenous thiobacilli and a leaching reactor which was used to leach metals from spent batteries. The indigenous acidophilic thiobacilli in sewage sludge was used as the microorganisms and the sludge itself as culture medium. Bioleaching tests at different hydraulic retention time (HRT) and process load in the leaching reactor were performed. The results showed that the longer the HRT (1, 3, 6, 9 and 15 days) was, the more time required to achieve the complete leaching of Ni, Cd and Co. The maximum dissolution of cadmium and cobalt was achieved at higher pH values (3.0-4.5) while the leaching of nickel hydroxide and nickel in metallic form (Ni{sup 0}) were obtained separately in different acidity (pH 2.5-3.5). It cost about 25, 30 and more than 40 days to remove all of the three heavy metals with the process load of two, four and eight Ni-Cd batteries under the conditions that the ingoing bio-sulphuric acid was 1 L d{sup -1} and HRT was 3 days.

  9. Should I stay or should I go? The impact of working time and wages on retention in the health workforce.

    Science.gov (United States)

    Steinmetz, Stephanie; de Vries, Daniel H; Tijdens, Kea G

    2014-04-23

    findings hold for all three countries, for a variety of health occupations. When following a policy of wage increases, attention to the issues of working time-including overtime hours, working part-time, and commuting time-and wage satisfaction are suitable strategies in managing health workforce retention.

  10. Postexercise rehydration with beer impairs fluid retention, reaction time, and balance.

    Science.gov (United States)

    Flores-Salamanca, Rebeca; Aragón-Vargas, Luis Fernando

    2014-10-01

    Beer is promoted by popular media as a good choice for rehydration, but there is limited support for the claim. To assess the effect of beer alcohol on rehydration and motor control, 11 young (24.4 ± 3.7 years old) males of legal drinking age were dehydrated to 2.12% ± 0.20% body mass (mean ± SD) by exercising in a climatic chamber (31.7 ± 1.6 °C, 55.0% ± 8.3% relative humidity) on 3 different days, 1 week apart, and rehydrated with 100% of their sweat loss using water (WATER), 4.6% alcohol beer (BEER), or low-alcohol beer (LAB), in random order. Urine output, blood alcohol content (BAC), reaction time (RT), and balance (as measured by center of pressure velocity (VCoP)) were measured every 30 min over 3 h and compared via 2-way, repeated-measures analyses of variance (ANOVAs). After consuming ≈1.6 L in 1 h, urine output was greater for BEER (1218 ± 279 mL) than for LAB (745 ± 313 mL, p = 0.007) and WATER (774 ± 304 mL, p = 0.043). BAC remained at 0 with WATER and LAB; with BEER, BAC reached 0.857 g/L (95% confidence intervals [0.752, 0.963]) immediately postrehydration. RT was longer for BEER (0.314 ± 0.039 s) than for LAB (0.294 ± 0.034 s, p = 0.009), but was no different from WATER (0.293 ± 0.049 s, p = 0.077). VCoPx was significantly higher for BEER (0.0284 ± 0.0020 m/s) compared with LAB (0.0233 ± 0.0010 m/s) or WATER (0.0238 ± 0.0010 m/s) (p = 0.022), but VCoPy was not different among beverages. In conclusion, rehydration with BEER resulted in higher diuresis, slower RT, and impaired VCoP than rehydration with LAB or WATER.

  11. Gastric Emptying in Patients with Diabetes: Gastric Emptying Time, Retention Rate and Effect of Cisapride

    International Nuclear Information System (INIS)

    Chung, Byung Chun; Choi, Chung Il; Gwak, Dong Suck; Lee, Jae Tae; Lee, Kyu Bo; Kim, Bo Wan; Chung, Jun Mo

    1992-01-01

    Gastic emptying scan in diabetic patients is widely used to assess the degree of motility disturbance and the symptoms such as nausea, vomiting, bloating, abdominal pain and early gastric fullness which we can't find anatomic lesion by fiberoscopic or barium study. In order to determine the relationship among diabetic gastropathy, neropathy, retinopathy and disease duration, gastric emptying scan using 99m Tc-tin colloid labeled scramble egg in hamburger was performed in 10 healthy male controls and 50 diabetic patients which were subdivided to no neuropathy, peripheral neuropathy and autonomic neuropathy groups according to the degree of diabetic neuropathy and no retinopathy, background retinopathy and proliferative retinopathy groups according to the degree of diabetic retinopathy. After medication of cisapride for 2 weeks, we observed the presence of improvement of gastric motility in diabetics. The results were as following: 1) In controls, gastric emptying time (GET1/2) was 75 ± 13.6 min and 2 hour gastric retension rate(GRR2) was 32 ± 11.1%. 2) In diabetics, GET/2 was prolonged more than 2 hours and GRR2 was 58 ± 23.1%. According to degree of neuropathy, GET1/2 was prolonged more than 2 hours in all three groups and GRR2 was 54± 24.1% in no neuropathy group, 57 ± 24.3% in peripheral neuropathy group and 69 ± 24.6% in autonomic neuropathy group. According to degree of retinopathy, GET1/2 was 110 ± 23.4 min in no retinopathy group and prolonged more than 2 hours in other two groups and GRR2 was 45 ± 21.6% in no retinopathy group, 71 ± 19.7% in background retinopathy group and 73 ± 21.5% in proliferative retinopathy group. 3) After cisapride for 2 weeks, GET1/2 and GRR2 were improved as 90 ± 14.6 min and 40 ± 13.8% (initial GET1/2 and GRR2 were above 2 hours and 61 ± 15.4%). We can conclude from above findings that gastropathy in diabetic neuropathy suggesting main underlying factor in motility disorder. The degree of retinopathy and disease

  12. Gastric Emptying in Patients with Diabetes: Gastric Emptying Time, Retention Rate and Effect of Cisapride

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Byung Chun; Choi, Chung Il; Gwak, Dong Suck; Lee, Jae Tae; Lee, Kyu Bo; Kim, Bo Wan; Chung, Jun Mo [Kyungpook National University School of Medicine, Daegu (Korea, Republic of)

    1992-07-15

    Gastic emptying scan in diabetic patients is widely used to assess the degree of motility disturbance and the symptoms such as nausea, vomiting, bloating, abdominal pain and early gastric fullness which we can't find anatomic lesion by fiberoscopic or barium study. In order to determine the relationship among diabetic gastropathy, neropathy, retinopathy and disease duration, gastric emptying scan using {sup 99m}Tc-tin colloid labeled scramble egg in hamburger was performed in 10 healthy male controls and 50 diabetic patients which were subdivided to no neuropathy, peripheral neuropathy and autonomic neuropathy groups according to the degree of diabetic neuropathy and no retinopathy, background retinopathy and proliferative retinopathy groups according to the degree of diabetic retinopathy. After medication of cisapride for 2 weeks, we observed the presence of improvement of gastric motility in diabetics. The results were as following: 1) In controls, gastric emptying time (GET1/2) was 75 +- 13.6 min and 2 hour gastric retension rate(GRR2) was 32 +- 11.1%. 2) In diabetics, GET/2 was prolonged more than 2 hours and GRR2 was 58 +- 23.1%. According to degree of neuropathy, GET1/2 was prolonged more than 2 hours in all three groups and GRR2 was 54+- 24.1% in no neuropathy group, 57 +- 24.3% in peripheral neuropathy group and 69 +- 24.6% in autonomic neuropathy group. According to degree of retinopathy, GET1/2 was 110 +- 23.4 min in no retinopathy group and prolonged more than 2 hours in other two groups and GRR2 was 45 +- 21.6% in no retinopathy group, 71 +- 19.7% in background retinopathy group and 73 +- 21.5% in proliferative retinopathy group. 3) After cisapride for 2 weeks, GET1/2 and GRR2 were improved as 90 +- 14.6 min and 40 +- 13.8% (initial GET1/2 and GRR2 were above 2 hours and 61 +- 15.4%). We can conclude from above findings that gastropathy in diabetic neuropathy suggesting main underlying factor in motility disorder. The degree of retinopathy and

  13. Correction of misleading information in prescription drug television advertising: The roles of advertisement similarity and time delay.

    Science.gov (United States)

    Aikin, Kathryn J; Southwell, Brian G; Paquin, Ryan S; Rupert, Douglas J; O'Donoghue, Amie C; Betts, Kevin R; Lee, Philip K

    Prescription drug television advertisements containing potentially consequential misinformation sometimes appear in the United States. When that happens, the U.S. Food and Drug Administration can request that companies distribute corrective advertisements to address misinformation and inaccurate claims. Previous research has demonstrated effectiveness in corrective advertising for various products. The present article builds on that work with a randomized experimental study (n = 6454) of corrective advertising investigating the extent to which visual similarity matters between violative and corrective ads and the extent to which time delay matters between violative and corrective advertisement exposure. Our study sample included overweight or obese U.S. adults recruited from an existing online consumer panel representative of the U.S. adult population. We created a brand for a fictitious prescription weight-loss drug and produced corresponding direct-to-consumer (DTC) television ads. All participants viewed the same violative ad, but were randomly assigned to view corrective ads with different levels of visual similarity and exposure time delay using a 4 × 4 between-subjects factorial design. Results suggest corrective ad exposure can influence consumer perceptions of drug efficacy, risks, and benefits previously established by violative ads that overstated drug efficacy, broadened drug indication, and omitted important risk information. Corrective ads also can weaken consumer intentions to consider and investigate a drug. However, ad similarity does not appear to affect consumer perceptions and preferences. Although we found that the effects of violative ad exposure tend to diminish over time, the length of the delay between violative and corrective ad exposure has limited influence. An exception to this was observed with regard to recall of drug benefits and risks, where the impact of corrective ad exposure increases with greater time delay. These results

  14. INFLUENCE OF HYDRAULIC RETENTION TIME ON EXTENT OF PCE DECHLORINATION AND PRELIMINARY CHARACTERIZATION OF THE ENRICHMENT CULTURE. (R826694C703)

    Science.gov (United States)

    The extent of tetrachloroethene (PCE) dechlorination in two chemostats was evaluated as a function of hydraulic retention time (HRT). The inoculum of these chemostats was from an upflow anaerobic sludge blanket (UASB) reactor that rapidly converts PCE to vinyl chloride (VC) an...

  15. Effects of dietary energy concentration, nonstarch polysaccharide concentration, and particle sizes of nonstarch polysaccharides on digesta mean retention time and gut development in laying hens

    NARCIS (Netherlands)

    Krimpen, van M.M.; Kwakkel, R.P.; Peet-Schwering, van der C.M.C.; Hartog, den L.A.; Verstegen, M.W.A.

    2011-01-01

    1. From an experiment with 504 laying hens (ISA Brown strain, 18–40 weeks of age), 90 40-week old hens were used for determining digesta mean retention time (MRT) and gut weight development. This experiment comprised 6 dietary treatments according to a 2¿×¿3 factorial design. Factors were dietary

  16. Effect of hydraulic retention time on deterioration/restarting of sludge anaerobic digestion: Extracellular polymeric substances and microbial response.

    Science.gov (United States)

    Wei, Liangliang; An, Xiaoyan; Wang, Sheng; Xue, Chonghua; Jiang, Junqiu; Zhao, Qingliang; Kabutey, Felix Tetteh; Wang, Kun

    2017-11-01

    In this study, the transformation of the sludge-related extracellular polymeric substances (EPS) during mesophilic anaerobic digestion was characterized to assess the effect of hydraulic retention time (HRT) on reactor deterioration/restarting. Experimental HRT variations from 20 to 15 and 10d was implemented for deterioration, and from 10 to 20d for restarting. Long-term digestion at the lowest HRT (10d) resulted in significant accumulation of hydrolyzed hydrophobic materials and volatile fatty acids in the supernatants. Moreover, less efficient hydrolysis of sludge EPS, especially of proteins related substances which contributed to the deterioration of digester. Aceticlastic species of Methanosaetaceae decreased from 36.3% to 27.6% with decreasing HRT (20-10d), while hydrogenotrophic methanogens (Methanomicrobiales and Methanobacteriales) increased from 30.4% to 38.3%. Proteins and soluble microbial byproducts related fluorophores in feed sludge for the anaerobic digester changed insignificantly at high HRT, whereas the fluorescent intensity of fulvic acid-like components declined sharply once the digestion deteriorated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Effect of Hydraulic Retention Time on Anaerobic Digestion of Wheat Straw in the Semicontinuous Continuous Stirred-Tank Reactors

    Directory of Open Access Journals (Sweden)

    Xiao-Shuang Shi

    2017-01-01

    Full Text Available Three semicontinuous continuous stirred-tank reactors (CSTR operating at mesophilic conditions (35°C were used to investigate the effect of hydraulic retention time (HRT on anaerobic digestion of wheat straw. The results showed that the average biogas production with HRT of 20, 40, and 60 days was 46.8, 79.9, and 89.1 mL/g total solid as well as 55.2, 94.3, and 105.2 mL/g volatile solids, respectively. The methane content with HRT of 20 days, from 14.2% to 28.5%, was the lowest among the three reactors. The pH values with HRT of 40 and 60 days were in the acceptable range compared to that with HRT of 20 days. The propionate was dominant in the reactor with HRT of 20 days, inhibiting the activities of methanogens and causing the lower methane content in biogas. The degradation of cellulose, hemicellulose, and crystalline cellulose based on XRD was also strongly influenced by HRTs.

  18. Effect of low solids retention time and focused pulsed pre-treatment on anaerobic digestion of waste activated sludge.

    Science.gov (United States)

    Lee, Il-Su; Rittmann, Bruce E

    2011-02-01

    The interacting effects of Focused Pulsed (FP) treatment and solids retention time (SRT) were evaluated in laboratory-scale digesters operated at SRTs of 2-20 days. Anaerobic digestion and methanogenesis of waste activated sludge (WAS) were stable for SRT ≥ 5 days, but the effluent soluble organic compounds increased significantly for SRT=2 days due to a combination of faster hydrolysis kinetics and washout of methanogens. FP treatment increased the CH(4) production rate and TCOD removal efficiency by up to 33% and 18%, respectively, at a SRT of 20 days. These effects were the result of an increase in the hydrolysis rate, since the concentrations of soluble components remained low for SRT ≥ 5 days. Alternately, FP pre-treatment of WAS allowed the same conversion of TCOD to CH(4) with a smaller SRT and digester size: e.g., 40% size savings with a CH(4) conversion of 0.23 g CH(4)-COD/g COD(in). Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Effect of sludge retention time on continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

    Science.gov (United States)

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-11-01

    The effect of sludge retention time (SRT) on the continuous-flow system with enhanced biological phosphorus removal (EBPR) granules at different COD loading was investigated during the operation of more than 220days. And the results showed that when the system operated at long SRT (30days) and low COD loading (200mg·L(-1)), it could maintain excellent performance. However, long SRT and high COD loading (300mg·L(-1)) deteriorated the settling ability of granules and the performance of system and resulted in the overgrowth of filamentous bacteria. Meanwhile, the transformation of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process was inhibited. Moreover, the results of pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading and long SRT. The PAOs specious of Candidatus_Accumlibater and system performance increased obviously when the SRT was reduced to 20days at high COD loading. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Effect of hydraulic retention time on ABR tail water treatment by contact oxidation process under low oxygen condition

    Science.gov (United States)

    Huang, Xiaolong; Shi, Chunhong; Wang, Zhenbao; Jiang, Kai

    2018-02-01

    Biological contact oxidation process of low dissolved oxygen was applied to the treatment of ABR tail water, which were pretreatment effluent for Island sewage. The reactor was built and filled with polyurethane suspension filler as carrier for biofilm growth in laboratory. The dissolved oxygen in the reactor is kept at 1.3-1.8mg/L to distinguish between traditional method which is 2.5-3.5mg/L. Influence of hydraulic retention time(HRT) on ABR tail water treatment by the process was studied. Results show that the system has good effect on removal of COD and TN under this condition. When HRT is among 4h to 12h, the removal rate of COD can be maintained at 80-90%.From period 1 to period 3, the removal rate of NH4 +N and TN at the end of each period can be recovered to a higher level, and the average removal rate after stabilization is 99% and 67% respectively which can come up to first grade of the national standard GB18918-2002. It is remarkable that when HRT is 4h, the removal rate of NH4 +-N and TN showed a significant decrease trend, the concentration of effluent was 14.79mg/L and 19.5mg/L, respectively.

  1. Self-Similar Nonlinear Dynamical Solutions for One-Component Nonneutral Plasma in a Time-Dependent Linear Focusing Field

    International Nuclear Information System (INIS)

    Qin, Hong; Davidson, Ronald C.

    2011-01-01

    In a linear trap confining a one-component nonneutral plasma, the external focusing force is a linear function of the configuration coordinates and/or the velocity coordinates. Linear traps include the classical Paul trap and the Penning trap, as well as the newly proposed rotating-radio- frequency traps and the Mobius accelerator. This paper describes a class of self-similar nonlinear solutions of nonneutral plasma in general time-dependent linear focusing devices, with self-consistent electrostatic field. This class of nonlinear solutions includes many known solutions as special cases.

  2. Series distance – an intuitive metric to quantify hydrograph similarity in terms of occurrence, amplitude and timing of hydrological events

    Directory of Open Access Journals (Sweden)

    U. Ehret

    2011-03-01

    Full Text Available Applying metrics to quantify the similarity or dissimilarity of hydrographs is a central task in hydrological modelling, used both in model calibration and the evaluation of simulations or forecasts. Motivated by the shortcomings of standard objective metrics such as the Root Mean Square Error (RMSE or the Mean Absolute Peak Time Error (MAPTE and the advantages of visual inspection as a powerful tool for simultaneous, case-specific and multi-criteria (yet subjective evaluation, we propose a new objective metric termed Series Distance, which is in close accordance with visual evaluation. The Series Distance quantifies the similarity of two hydrographs neither in a time-aggregated nor in a point-by-point manner, but on the scale of hydrological events. It consists of three parts, namely a Threat Score which evaluates overall agreement of event occurrence, and the overall distance of matching observed and simulated events with respect to amplitude and timing. The novelty of the latter two is the way in which matching point pairs on the observed and simulated hydrographs are identified: not by equality in time (as is the case with the RMSE, but by the same relative position in matching segments (rise or recession of the event, indicating the same underlying hydrological process. Thus, amplitude and timing errors are calculated simultaneously but separately, from point pairs that also match visually, considering complete events rather than only individual points (as is the case with MAPTE. Relative weights can freely be assigned to each component of the Series Distance, which allows (subjective customization of the metric to various fields of application, but in a traceable way. Each of the three components of the Series Distance can be used in an aggregated or non-aggregated way, which makes the Series Distance a suitable tool for differentiated, process-based model diagnostics.

    After discussing the applicability of established time series

  3. Reducing turnaround time for laboratory test results does not improve retention of stable HIV-infected adults on POV program: experience from Uganda.

    Science.gov (United States)

    Maselle, Edna; Muhanguzi, Asaph; Muhumuza, Simon; Nansubuga, Jeniffer; Nawavvu, Cecilia; Namusobya, Jeniffer; Kamya, Moses R; Semitala, Fred C

    2014-01-01

    HIV/ AIDS clinics in resource limited settings (RLS) face increasing numbers of patients and workforce shortage [1, 2]. To address these challenges, efficient models of care like pharmacy only visits (POV) and nurse only visits (NOV) are recommended [3]. The Makerere University Joint AIDS Program (MJAP), a PEPFAR funded program providing care to over 42,000 HIV infected adults has implemented the POV model since 2009. In this model, stable patients on antiretroviral therapy (ART) with adherence to ART >95% and Karnofsky score >90% are reviewed by a doctor every four months but visit pharmacy for ART re-fills every two months. A study conducted in August 2011 showed low retention on the POV program with symptomatic diseases, pending CD4 count, complete blood count results, and poor adherence to ART as the major reasons for the non-retention in the POV program. To improve retention on POV, the TAT (Turnaround Time) for laboratory results (the main reason for non-retention in the previous study) was reduced from one month to one week. In August 2012, the study was repeated to assess the effect of reducing TAT on improving retention one year after patients were placed on POV. A cohort analysis of data from patients in August 2011 and in August 2012 on POV was done. We compared retention of POV before and after reducing the TAT for laboratory results. Retention on POV was 12.0% (95% CI 9.50-14.7) among 619 patients in 2011, (70% Females), mean age was 33 years, Standard Deviation (SD) 8.5 compared to 11.1% (95% CI 9.15-13.4) among 888 patients (70% Females), mean age 38.3 years, SD 8.9 in 2012 (p=0.59). The main reasons for non-retention on the POV program in 2012 were poor adherence to ART (23%) and missed clinic appointments (14%). Reducing TAT for laboratory test results did not improve retention of stable HIV-infected adults on POV in our clinic. Strategies for improving adherence to ART and keeping clinic appointments need to be employed to balance workload and

  4. Similarity in Chronotype and Preferred Time for Sex and Its Role in Relationship Quality and Sexual Satisfaction

    Directory of Open Access Journals (Sweden)

    Paulina Jocz

    2018-04-01

    Full Text Available Recently, the issue of diurnal preferences has been increasingly studied within the context of romantic relationships and sexual functioning. In the present paper we apply a dyadic design to investigate the role of romantic partners' diurnal preferences in determining a variety of relationship outcomes. A sample of 91 heterosexual couples completed a set of questionnaires measuring relationship satisfaction, sexual satisfaction, and morningness-eveningness, and answered questions regarding their actual and preferred time for sexual activity. Conducted analyses revealed that similarity in chronotype between partners and female morningness fostered relationship satisfaction in females, but not in males. Furthermore, morningness-eveningness was associated with preferred time for sex in males, but not in females, who in principle preferred evening hours. Although actual time for sex was up to the female preference, sexual satisfaction in both genders was associated with lower discrepancy in their preferred time for sex and greater frequency of intercourse. In sum, these results indicate that chronotype and time for sex are important factors affecting sexual and relationships satisfaction in heterosexual couples.

  5. Chemical dynamics between wells across a time-dependent barrier: Self-similarity in the Lagrangian descriptor and reactive basins.

    Science.gov (United States)

    Junginger, Andrej; Duvenbeck, Lennart; Feldmaier, Matthias; Main, Jörg; Wunner, Günter; Hernandez, Rigoberto

    2017-08-14

    In chemical or physical reaction dynamics, it is essential to distinguish precisely between reactants and products for all times. This task is especially demanding in time-dependent or driven systems because therein the dividing surface (DS) between these states often exhibits a nontrivial time-dependence. The so-called transition state (TS) trajectory has been seen to define a DS which is free of recrossings in a large number of one-dimensional reactions across time-dependent barriers and thus, allows one to determine exact reaction rates. A fundamental challenge to applying this method is the construction of the TS trajectory itself. The minimization of Lagrangian descriptors (LDs) provides a general and powerful scheme to obtain that trajectory even when perturbation theory fails. Both approaches encounter possible breakdowns when the overall potential is bounded, admitting the possibility of returns to the barrier long after the trajectories have reached the product or reactant wells. Such global dynamics cannot be captured by perturbation theory. Meanwhile, in the LD-DS approach, it leads to the emergence of additional local minima which make it difficult to extract the optimal branch associated with the desired TS trajectory. In this work, we illustrate this behavior for a time-dependent double-well potential revealing a self-similar structure of the LD, and we demonstrate how the reflections and side-minima can be addressed by an appropriate modification of the LD associated with the direct rate across the barrier.

  6. Comparison of multiple linear regression, partial least squares and artificial neural networks for prediction of gas chromatographic relative retention times of trimethylsilylated anabolic androgenic steroids.

    Science.gov (United States)

    Fragkaki, A G; Farmaki, E; Thomaidis, N; Tsantili-Kakoulidou, A; Angelis, Y S; Koupparis, M; Georgakopoulos, C

    2012-09-21

    The comparison among different modelling techniques, such as multiple linear regression, partial least squares and artificial neural networks, has been performed in order to construct and evaluate models for prediction of gas chromatographic relative retention times of trimethylsilylated anabolic androgenic steroids. The performance of the quantitative structure-retention relationship study, using the multiple linear regression and partial least squares techniques, has been previously conducted. In the present study, artificial neural networks models were constructed and used for the prediction of relative retention times of anabolic androgenic steroids, while their efficiency is compared with that of the models derived from the multiple linear regression and partial least squares techniques. For overall ranking of the models, a novel procedure [Trends Anal. Chem. 29 (2010) 101-109] based on sum of ranking differences was applied, which permits the best model to be selected. The suggested models are considered useful for the estimation of relative retention times of designer steroids for which no analytical data are available. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Shift workers have similar leisure-time physical activity levels as day workers but are more sedentary at work.

    Science.gov (United States)

    Hulsegge, Gerben; Gupta, Nidhi; Holtermann, Andreas; Jørgensen, Marie Birk; Proper, Karin I; van der Beek, Allard J

    2017-03-01

    Objective Physical inactivity has been hypothesized as an underlying factor for the association between shift work and adverse health outcomes. We compared leisure-time and occupational physical activity and sedentary behavior between day, night, and non-night shift workers. Methods We identified 612 day workers, 139 night shift workers and 61 non-night shift workers aged 18-65 years (54% men) in two Danish studies: the New method for Objective Measurements of physical Activity in Daily living (NOMAD) and the Danish Physical ACTivity cohort with Objective measurements (DPhacto) between 2011-2013. Sedentary behavior, light, and moderate-to-vigorous physical activity were measured using an accelerometer. Physical activity was expressed as percentage of leisure and work time spent in each activity. Linear regression analyses were used to test differences in physical activity and sedentary behavior between day, night, and non-night shift workers. Results No differences in leisure-time sedentary behavior and physical activity were observed between day and shift workers (P>0.05). Non-night shift workers spent 7.2% [95% confidence interval (95% CI) 2.3-12.1) more time in occupational sedentary behavior than day workers and 5.9% (95% CI -10.1- -1.7) and 1.9% (95% CI -3.7- -0.2) less time in occupational light and moderate-to-vigorous physical activity, respectively. Compared to day workers, night shift workers spent 4.3% (95% CI 2.4-6.1) more time at work in uninterrupted sedentary periods of ≥30 minutes. Conclusions Shift workers had similar leisure-time physical activity patterns as day workers, but were more sedentary at work. Future research should elucidate whether occupational physical inactivity and sedentary behavior contributes to shift work-related adverse health effects.

  8. Influence of Hydraulic Retention Time on Biogas Production from Frozen Seafood Wastewater using Decanter Cake as Anaerobic Co-digestion Material

    OpenAIRE

    Thaniya Kaosol; Narumol Sohgrathok

    2012-01-01

    In this research, an anaerobic co-digestion using decanter cake from palm oil mill industry to improve the biogas production from frozen seafood wastewater is studied using Continuously Stirred Tank Reactor (CSTR) process. The experiments were conducted in laboratory-scale. The suitable Hydraulic Retention Time (HRT) was observed in CSTR experiments with 24 hours of mixing time using the mechanical mixer. The HRT of CSTR process impacts on the efficiency of biogas production. The best perform...

  9. Semi-continuous anaerobic digestion of solid poultry slaughterhouse waste: effect of hydraulic retention time and loading.

    Science.gov (United States)

    Salminen, Esa A; Rintala, Jukka A

    2002-07-01

    We studied the effect of hydraulic retention time (HRT) and loading on anaerobic digestion of poultry slaughterhouse wastes, using semi-continuously fed, laboratory-scale digesters at 31 degrees C. The effect on process performance was highly significant: Anaerobic digestion appeared feasible with a loading of up to 0.8 kg volatile solids (VS)/m3 d and an HRT of 50-100 days. The specific methane yield was high, from 0.52 to 0.55 m3/kg VS(added). On the other hand, at a higher loading, in the range from 1.0 to 2.1 kg VS/m3 d, and a shorter HRT, in the range from 25 to 13 days, the process appeared inhibited and/or overloaded, as indicated by the accumulation of volatile fatty acids and long-chain fatty acids and the decline in the methane yield. However, the inhibition was reversible. The nitrogen in the feed, ca. 7.8% of total solids (TS), was organic nitrogen with little ammonia present, whereas in the digested material ammonia accounted for 52-67% (up to 3.8 g/l) of total nitrogen. The TS and VS removals amounted to 76% and 64%, respectively. Our results show that on a continuous basis under the studied conditions and with a loading of up to 0.8 kg VS/m3 d metric ton (wet weight) of the studied waste mixture could yield up to 140 m3 of methane.

  10. Effect of hydraulic retention time on the biodegradation of complex phenolic mixture from simulated coal wastewater in hybrid UASB reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Anushuya [Centre for Environmental Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India); Gupta, Sudhir Kumar [Centre for Environmental Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)], E-mail: skgupta@iitb.ac.in

    2008-05-01

    This study describes the feasibility of anaerobic treatment of complex phenolics mixture from a simulated synthetic coal wastewater using four identical 13.5 L (effective volume) bench scale hybrid up-flow anaerobic sludge blanket (HUASB) (combining UASB + anaerobic filter) reactors at four different hydraulic retention times (HRT) under mesophilic (27 {+-} 5 {sup o}C) conditions. Synthetic coal wastewater with an average chemical oxygen demand (COD) of 2240 mg/L and phenolics concentration of 752 mg/L was used as substrate. The phenolics contained phenol (490 mg/L); m-, o-, p-cresols (123.0, 58.6, 42 mg/L); 2,4-, 2,5-, 3,4- and 3,5-dimethyl phenols (6.3, 6.3, 4.4 and 21.3 mg/L) as major phenolic compounds. The study demonstrated that at optimum HRT, 24 h, and phenolic loading rate of 0.75 g COD/(m{sup 3}-d), the phenolics and COD removal efficiency of the reactors were 96% and 86%, respectively. Bio-kinetic models were applied to data obtained from experimental studies in hybrid UASB reactor. Grau second-order multi-component substrate removal model was best fitted to the hybrid UASB reactor. The second-order substrate removal rate constant (k{sub 2(s)}) was found as 1.72 h{sup -1} for the hybrid reactor treating complex phenolic mixture. Morphological examination of the sludge revealed rod-type Methanothrix-like, cells to be dominant on the surface.

  11. Effect of hydraulic retention time on the biodegradation of complex phenolic mixture from simulated coal wastewater in hybrid UASB reactors

    International Nuclear Information System (INIS)

    Ramakrishnan, Anushuya; Gupta, Sudhir Kumar

    2008-01-01

    This study describes the feasibility of anaerobic treatment of complex phenolics mixture from a simulated synthetic coal wastewater using four identical 13.5 L (effective volume) bench scale hybrid up-flow anaerobic sludge blanket (HUASB) (combining UASB + anaerobic filter) reactors at four different hydraulic retention times (HRT) under mesophilic (27 ± 5 o C) conditions. Synthetic coal wastewater with an average chemical oxygen demand (COD) of 2240 mg/L and phenolics concentration of 752 mg/L was used as substrate. The phenolics contained phenol (490 mg/L); m-, o-, p-cresols (123.0, 58.6, 42 mg/L); 2,4-, 2,5-, 3,4- and 3,5-dimethyl phenols (6.3, 6.3, 4.4 and 21.3 mg/L) as major phenolic compounds. The study demonstrated that at optimum HRT, 24 h, and phenolic loading rate of 0.75 g COD/(m 3 -d), the phenolics and COD removal efficiency of the reactors were 96% and 86%, respectively. Bio-kinetic models were applied to data obtained from experimental studies in hybrid UASB reactor. Grau second-order multi-component substrate removal model was best fitted to the hybrid UASB reactor. The second-order substrate removal rate constant (k 2(s) ) was found as 1.72 h -1 for the hybrid reactor treating complex phenolic mixture. Morphological examination of the sludge revealed rod-type Methanothrix-like, cells to be dominant on the surface

  12. Successful operation of continuous reactors at short retention times results in high-density, fast-rate Dehalococcoides dechlorinating cultures.

    Science.gov (United States)

    Delgado, Anca G; Fajardo-Williams, Devyn; Popat, Sudeep C; Torres, César I; Krajmalnik-Brown, Rosa

    2014-03-01

    The discovery of Dehalococcoides mccartyi reducing perchloroethene and trichloroethene (TCE) to ethene was a key landmark for bioremediation applications at contaminated sites. D. mccartyi-containing cultures are typically grown in batch-fed reactors. On the other hand, continuous cultivation of these microorganisms has been described only at long hydraulic retention times (HRTs). We report the cultivation of a representative D. mccartyi-containing culture in continuous stirred-tank reactors (CSTRs) at a short, 3-d HRT, using TCE as the electron acceptor. We successfully operated 3-d HRT CSTRs for up to 120 days and observed sustained dechlorination of TCE at influent concentrations of 1 and 2 mM TCE to ≥ 97 % ethene, coupled to the production of 10(12) D. mccartyi cells Lculture (-1). These outcomes were possible in part by using a medium with low bicarbonate concentrations (5 mM) to minimize the excessive proliferation of microorganisms that use bicarbonate as an electron acceptor and compete with D. mccartyi for H2. The maximum conversion rates for the CSTR-produced culture were 0.13 ± 0.016, 0.06 ± 0.018, and 0.02 ± 0.007 mmol Cl(-) Lculture (-1) h(-1), respectively, for TCE, cis-dichloroethene, and vinyl chloride. The CSTR operation described here provides the fastest laboratory cultivation rate of high-cell density Dehalococcoides cultures reported in the literature to date. This cultivation method provides a fundamental scientific platform for potential future operations of such a system at larger scales.

  13. Effect of hydraulic retention time on biohydrogen and volatile fatty acids production during acidogenic digestion of dephenolized olive mill wastewaters

    International Nuclear Information System (INIS)

    Scoma, Alberto; Bertin, Lorenzo; Fava, Fabio

    2013-01-01

    The influence of Hydraulic Retention Time (HRT) on the performances of a recently developed biotechnological anaerobic acidogenic process fed with dephenolized Olive Mill Wastewater (OMW) was investigated. The study was carried out under mesophilic conditions in Packed Bed Biofilm Reactors (PBBRs), filled with ceramic cubes and inoculated with a characterized and acclimated acidogenic microbial consortium. The PBBRs were fed with a HRT of 7, 5, 3 or 1 day, which corresponded to Organic Loading Rates (OLRs) of about 5.5, 7.8, 12.9 and 38.8 g L −1 d −1 , respectively. A significant production of a H 2 -rich biogas was observed when shorter HRTs were applied: in particular, H 2 relative amount and productivity increased from 3% to 32% and from 0.20 to 6.10 dm 3 m −3 h −1 , respectively, by decreasing the HRT from 7 to 1 day. On the contrary, shorter HRTs turned into a lower accumulation of Volatile Fatty Acids (VFAs), whose highest amounts were found with HRTs of 7 and 5 days (about 18.4 and 19.7 g L −1 COD equivalents, respectively). The highest conversion yield of COD into VFAs (36%) was obtained with a HRT of 5 days, when VFAs represented about 78% of the effluent COD. HRT also influenced the composition of the VFA mixture: acetic, propionic and butyric acid were the most prominent VFAs, being their relative amounts higher when PBBRs were operated with shorter HRTs (up to 19, 12 and 42% of the whole mixture, respectively, when HRT was 1 day). -- Highlights: ► HRT affects the acidogenic digestion of dephenolized olive mill wastewater. ► A significant production of bioH 2 can be coupled to that of volatile fatty acids. ► Higher H 2 and lower VFA productions were obtained by shortening the HRT

  14. Bioaugmentation of anaerobic sludge digestion with iron-reducing bacteria: process and microbial responses to variations in hydraulic retention time.

    Science.gov (United States)

    Baek, Gahyun; Kim, Jaai; Shin, Seung Gu; Lee, Changsoo

    2016-01-01

    Although anaerobic digestion (AD) is a widely used option to manage waste activated sludge (WAS), there are some drawbacks related to its slow reaction rate and low energy productivity. This study examined an anaerobic WAS digester, augmented with an iron-reducing microbial consortium, relative to changes in microbial community structure and process performance at decreasing hydraulic retention times (HRTs) of 20 to 10 days. The enhanced methanation performance (approximately 40 % increase in methane yield) by the bioaugmentation was sustained until the HRT was decreased to 12.5 days, under Fe(3+)-rich conditions (ferric oxyhydroxide, 20 mM Fe). Enhanced iron-reducing activity was evidenced by the increased Fe(2+) to total Fe ratio maintained above 50 % during the stable operational phases. A further decrease in HRT to 10 days resulted in a significant performance deterioration, along with a drop in the Fe(2+) to total Fe ratio to bacteria (IRBs) was identified by denaturing gradient gel electrophoresis (DGGE), with Spirochaetaceae- and Thauera-related organisms being dominant members, and clear dominance shifts among them with respect to decrease in HRT were observed. Lowering HRT led to evident shifts in bacterial community structure likely associated with washout of IRBs, leading to decreases in iron respiration activity and AD performance at a lower HRT. The bacterial community structure shifted dynamically over phases, and the community transitions correlated well with the changes in process performance. Overall, the combined biostimulation and bioaugmentation investigated in this study proved effective for enhanced methane recovery from anaerobic WAS digestion, which suggests an interesting potential for high-rate AD.

  15. Suspected-target pesticide screening using gas chromatography-quadrupole time-of-flight mass spectrometry with high resolution deconvolution and retention index/mass spectrum library.

    Science.gov (United States)

    Zhang, Fang; Wang, Haoyang; Zhang, Li; Zhang, Jing; Fan, Ruojing; Yu, Chongtian; Wang, Wenwen; Guo, Yinlong

    2014-10-01

    A strategy for suspected-target screening of pesticide residues in complicated matrices was exploited using gas chromatography in combination with hybrid quadrupole time-of-flight mass spectrometry (GC-QTOF MS). The screening workflow followed three key steps of, initial detection, preliminary identification, and final confirmation. The initial detection of components in a matrix was done by a high resolution mass spectrum deconvolution; the preliminary identification of suspected pesticides was based on a special retention index/mass spectrum (RI/MS) library that contained both the first-stage mass spectra (MS(1) spectra) and retention indices; and the final confirmation was accomplished by accurate mass measurements of representative ions with their response ratios from the MS(1) spectra or representative product ions from the second-stage mass spectra (MS(2) spectra). To evaluate the applicability of the workflow in real samples, three matrices of apple, spinach, and scallion, each spiked with 165 test pesticides in a set of concentrations, were selected as the models. The results showed that the use of high-resolution TOF enabled effective extractions of spectra from noisy chromatograms, which was based on a narrow mass window (5 mDa) and suspected-target compounds identified by the similarity match of deconvoluted full mass spectra and filtering of linear RIs. On average, over 74% of pesticides at 50 ng/mL could be identified using deconvolution and the RI/MS library. Over 80% of pesticides at 5 ng/mL or lower concentrations could be confirmed in each matrix using at least two representative ions with their response ratios from the MS(1) spectra. In addition, the application of product ion spectra was capable of confirming suspected pesticides with specificity for some pesticides in complicated matrices. In conclusion, GC-QTOF MS combined with the RI/MS library seems to be one of the most efficient tools for the analysis of suspected-target pesticide residues

  16. Artificial neural network modelling of pharmaceutical residue retention times in wastewater extracts using gradient liquid chromatography-high resolution mass spectrometry data.

    Science.gov (United States)

    Munro, Kelly; Miller, Thomas H; Martins, Claudia P B; Edge, Anthony M; Cowan, David A; Barron, Leon P

    2015-05-29

    The modelling and prediction of reversed-phase chromatographic retention time (tR) under gradient elution conditions for 166 pharmaceuticals in wastewater extracts is presented using artificial neural networks for the first time. Radial basis function, multilayer perceptron and generalised regression neural networks were investigated and a comparison of their predictive ability for model solutions discussed. For real world application, the effect of matrix complexity on tR measurements is presented. Measured tR for some compounds in influent wastewater varied by >1min in comparison to tR in model solutions. Similarly, matrix impact on artificial neural network predictive ability was addressed towards developing a more robust approach for routine screening applications. Overall, the best neural network had a predictive accuracy of <1.3min at the 75th percentile of all measured tR data in wastewater samples (<10% of the total runtime). Coefficients of determination for 30 blind test compounds in wastewater matrices lay at or above R(2)=0.92. Finally, the model was evaluated for application to the semi-targeted identification of pharmaceutical residues during a weeklong wastewater sampling campaign. The model successfully identified native compounds at a rate of 83±4% and 73±5% in influent and effluent extracts, respectively. The use of an HRMS database and the optimised ANN model was also applied to shortlisting of 37 additional compounds in wastewater. Ultimately, this research will potentially enable faster identification of emerging contaminants in the environment through more efficient post-acquisition data mining. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Robust estimation of thermodynamic parameters (ΔH, ΔS and ΔCp) for prediction of retention time in gas chromatography - Part I (Theoretical).

    Science.gov (United States)

    Claumann, Carlos Alberto; Wüst Zibetti, André; Bolzan, Ariovaldo; Machado, Ricardo A F; Pinto, Leonel Teixeira

    2015-12-18

    An approach that is commonly used for calculating the retention time of a compound in GC departs from the thermodynamic properties ΔH, ΔS and ΔCp of phase change (from mobile to stationary). Such properties can be estimated by using experimental retention time data, which results in a non-linear regression problem for non-isothermal temperature programs. As shown in this work, the surface of the objective function (approximation error criterion) on the basis of thermodynamic parameters can be divided into three clearly defined regions, and solely in one of them there is a possibility for the global optimum to be found. The main contribution of this study was the development of an algorithm that distinguishes the different regions of the error surface and its use in the robust initialization of the estimation of parameters ΔH, ΔS and ΔCp. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Time indices of multiphasic development in genotypes of sweet cherry are similar from dormancy to cessation of pit growth.

    Science.gov (United States)

    Gibeaut, David M; Whiting, Matthew D; Einhorn, Todd

    2017-02-01

    The archetypical double sigmoid-shaped growth curve of the sweet cherry drupe (Prunus avium) does not address critical development from eco-dormancy to anthesis and has not been correlated to reproductive bud development. Accurate representation of the growth and development of post-anthesis ovaries is confounded by anthesis timing, fruiting-density and the presence of unfertilized and defective ovaries whose growth differs from those that persist to maturation. These factors were addressed to assess pre-anthesis and full-season growth and development of three sweet cherry cultivars, 'Chelan', 'Bing' and 'Sweetheart', differing primarily in seasonal duration and fruit size. Volume was calculated from photographic measurements of reproductive buds, ovaries and pits at all phases of development. A population of unfertilized ovaries was produced using bee-exclusion netting to enable a statistical comparison with an open pollinated population to detect differences in size and shape between successful and failing fruit growth. Anthesis timing and fruiting-density were manipulated by floral extinction at the spur and whole-tree scales. Developmental time indices were analysed using polynomial curve fitting of log-transformed data supported by Richards and logistic functions of asymptotic growth of the pit and maturing fruit, respectively. Pre-anthesis growth began at the completion of eco-dormancy. A slight decline in relative growth rate (RGR) was observed during bud scale separation approx. -16 d from anthesis (DFA) before resumption of exponential growth to a maximum about 14 DFA. After anthesis, reduced growth of unfertilized or defective ovaries was partly discriminated from successful fruit at 5 DFA and completely at 25 DFA. Time indices of RGR inflections were similar among cultivars when adjusted for anthesis date alone, until the end of pit growth. Asymptotic growth of the pit underpinned the declining growth rate of fruit at the end of the first exponential

  19. Morphometry and retention time as forcing functions to establishment and maintenance of aquatic macrophytes in a tropical reservoir

    Directory of Open Access Journals (Sweden)

    M. B. Cunha-Santino

    Full Text Available Abstract Macrophytes may constitute an important resource for several chemical, physical and biological processes within aquatic ecosystems. This study considers that in tropical reservoirs with low retention time and with low values of shoreline development (DL, the expansion and persistence of aquatic macrophytes are mainly reported to local conditions (e.g., hydrodynamic and wind exposure rather than trophic status and depth of the euphotic zone. In this context, this study aimed at describing and comparing the incidence of aquatic macrophytes in a throughflowing, non-dendritic tropical reservoir. During February 2006 to November 2007, eight limnological surveys were performed quarterly within the Ourinhos Reservoir, and in the mouth areas of its tributaries. At the six sampling stations 30 variables were measured. The number of sites with plants varied between 21 and 38 and at the end of the 1st year the total richness was found. The sampling survey outcome the recognition of 18 species of aquatic macrophytes; Cyperaceae (2 genera and 1 species, Pontederiaceae (3 species and Onarograceae (3 genera were the families with higher diversity. Seven species (Typha domingensis Pers., Myriophyllum aquaticum (Vell. Verdec, Salvinia auriculata Aubl., Eichhornia azurea (Sw. Kunth, Eleocharis sp1, Eichhornia crassipes (Mart. Solms, Oxycaryum cubense (Poepp. & Kunth Lye always were present and were more frequent in the sites. The occurrence of emergent species predominated (45.9%, followed by submersed rooted (24.5%, free floating (19.5%, floating rooted (9.7% and free submersed (0.3%. Although limnological variables and the distribution of macrophytes have discriminated the same sampling points, the stepwise multiple linear regressions did not pointed out strong correspondences (or coherence among the most constant and distributed macrophyte species and the selected limnological variables, as well the trophic statuses. Seeing the low relationship among

  20. Morphometry and retention time as forcing functions to establishment and maintenance of aquatic macrophytes in a tropical reservoir.

    Science.gov (United States)

    Cunha-Santino, M B; Fushita, A T; Peret, A C; Bianchini-Junior, I

    2016-05-03

    Macrophytes may constitute an important resource for several chemical, physical and biological processes within aquatic ecosystems. This study considers that in tropical reservoirs with low retention time and with low values of shoreline development (DL), the expansion and persistence of aquatic macrophytes are mainly reported to local conditions (e.g., hydrodynamic and wind exposure) rather than trophic status and depth of the euphotic zone. In this context, this study aimed at describing and comparing the incidence of aquatic macrophytes in a throughflowing, non-dendritic tropical reservoir. During February 2006 to November 2007, eight limnological surveys were performed quarterly within the Ourinhos Reservoir, and in the mouth areas of its tributaries. At the six sampling stations 30 variables were measured. The number of sites with plants varied between 21 and 38 and at the end of the 1st year the total richness was found. The sampling survey outcome the recognition of 18 species of aquatic macrophytes; Cyperaceae (2 genera and 1 species), Pontederiaceae (3 species) and Onarograceae (3 genera) were the families with higher diversity. Seven species (Typha domingensis Pers., Myriophyllum aquaticum (Vell.) Verdec, Salvinia auriculata Aubl., Eichhornia azurea (Sw.) Kunth, Eleocharis sp1, Eichhornia crassipes (Mart.) Solms, Oxycaryum cubense (Poepp. & Kunth) Lye) always were present and were more frequent in the sites. The occurrence of emergent species predominated (45.9%), followed by submersed rooted (24.5%), free floating (19.5%), floating rooted (9.7%) and free submersed (0.3%). Although limnological variables and the distribution of macrophytes have discriminated the same sampling points, the stepwise multiple linear regressions did not pointed out strong correspondences (or coherence) among the most constant and distributed macrophyte species and the selected limnological variables, as well the trophic statuses. Seeing the low relationship among limnological

  1. Urinary retention in women.

    Science.gov (United States)

    Juma, Saad

    2014-07-01

    This review is a summary of the most pertinent published studies in the literature in the last 18 months that address cause, diagnosis, and management of urinary retention in women. Symptoms, uroflow, and pressure-flow studies have a low predictive value for and do not correlate with elevated postvoid residual urine (PVR). Anterior and posterior colporrhaphy do not cause de-novo bladder outlet obstruction in the majority of patients with elevated PVR, and the cause of elevated PVR may be other factors such as pain or anxiety causing abnormal relaxation of the pelvic floor and contributing to voiding difficulty. The risk of urinary retention in a future pregnancy after mid-urethral sling (MUS) is small. The risk of urinary tract infection and urinary retention after chemodenervation of the bladder with onabotulinumtoxin-A (100 IU) in patients with non-neurogenic urge incontinence is 33 and 5%, respectively. There is a lack of consensus among experts on the timing of sling takedown in the management of acute urinary retention following MUS procedures. There has been a significant progress in the understanding of the causation of urinary retention. Important areas that need further research (basic and clinical) are post-MUS and pelvic organ prolapse repair urinary retention and obstruction, and urinary retention owing to detrusor underactivity.

  2. Similarity measure and topology evolution of foreign exchange markets using dynamic time warping method: Evidence from minimal spanning tree

    Science.gov (United States)

    Wang, Gang-Jin; Xie, Chi; Han, Feng; Sun, Bo

    2012-08-01

    In this study, we employ a dynamic time warping method to study the topology of similarity networks among 35 major currencies in international foreign exchange (FX) markets, measured by the minimal spanning tree (MST) approach, which is expected to overcome the synchronous restriction of the Pearson correlation coefficient. In the empirical process, firstly, we subdivide the analysis period from June 2005 to May 2011 into three sub-periods: before, during, and after the US sub-prime crisis. Secondly, we choose NZD (New Zealand dollar) as the numeraire and then, analyze the topology evolution of FX markets in terms of the structure changes of MSTs during the above periods. We also present the hierarchical tree associated with the MST to study the currency clusters in each sub-period. Our results confirm that USD and EUR are the predominant world currencies. But USD gradually loses the most central position while EUR acts as a stable center in the MST passing through the crisis. Furthermore, an interesting finding is that, after the crisis, SGD (Singapore dollar) becomes a new center currency for the network.

  3. Characterizing multi-scale self-similar behavior and non-statistical properties of fluctuations in financial time series

    Science.gov (United States)

    Ghosh, Sayantan; Manimaran, P.; Panigrahi, Prasanta K.

    2011-11-01

    We make use of wavelet transform to study the multi-scale, self-similar behavior and deviations thereof, in the stock prices of large companies, belonging to different economic sectors. The stock market returns exhibit multi-fractal characteristics, with some of the companies showing deviations at small and large scales. The fact that, the wavelets belonging to the Daubechies’ (Db) basis enables one to isolate local polynomial trends of different degrees, plays the key role in isolating fluctuations at different scales. One of the primary motivations of this work is to study the emergence of the k-3 behavior [X. Gabaix, P. Gopikrishnan, V. Plerou, H. Stanley, A theory of power law distributions in financial market fluctuations, Nature 423 (2003) 267-270] of the fluctuations starting with high frequency fluctuations. We make use of Db4 and Db6 basis sets to respectively isolate local linear and quadratic trends at different scales in order to study the statistical characteristics of these financial time series. The fluctuations reveal fat tail non-Gaussian behavior, unstable periodic modulations, at finer scales, from which the characteristic k-3 power law behavior emerges at sufficiently large scales. We further identify stable periodic behavior through the continuous Morlet wavelet.

  4. Managing retention.

    Science.gov (United States)

    Carter, Tony

    2007-01-01

    To build this process it is necessary to consult customers for preferences, build familiarity and knowledge to build a relationship and conduct business in a customized fashion. The process takes every opportunity to build customer satisfaction with each customer contact. It is an important process to have, since customers today are more demanding, sophisticated, educated and comfortable speaking to the company as an equal (Belk, 2003). Customers have more customized expectations so they want to be reached as individuals (Raymond and Tanner, 1994). Also, a disproportionate search for new business is costly. The cost to cultivate new customers is more than maintaining existing customers (Cathcart, 1990). Other reasons that customer retention is necessary is because many unhappy customers will never buy again from a company that dissatisfied them and they will communicate their displeasure to other people. These dissatisfied customers may not even convey their displeasure but without saying anything just stop doing business with that company, which may keep them unaware for some time that there is any problem (Cathcart, 1990).

  5. Relationship Between Timing of Multiple Retention Bonuses and the Quality of Officers Retained on the Cost Savings for the Navy

    Science.gov (United States)

    2016-12-01

    psychologically anchor an item’s value at a high price before lowering it until one bidder accepts, earning its name from the way cut flowers are sold...Using the standard bonus system compared to the uniform price auction, the Quality Adjusted Discount (QUAD) auction, and Combinatorial Retention...NUMBER OF PAGES 85 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS PAGE Unclassified 19

  6. The effect of graphic design materials on the retention level of viewers in prime time television newscasts

    OpenAIRE

    Ertep, Rifat Hakan

    1996-01-01

    Ankara : Institute of Economics and Social Sciences, Bilkent Univ., 1996. Thesis (Ph.D.) -- Bilkent University, 1996. Includes bibliographical references. This study investigates the role of graphic design materials in improving the recall and retention level of television news viewers, and examines the capacity and power of these materials to shape or distort people's perception of reality. To this end, two experiments have been conducted with the aim of providing an emp...

  7. Echoic memory in the rat: effects of inspection time, retention interval, and the spectral composition of masking noise.

    Science.gov (United States)

    O'Connor, K; Ison, J R

    1991-10-01

    Memory for tones (1100 vs. 2330 Hz) was studied in 4 rats (Rattus norvegicus), as affected by the durations of both target tones (30 to 620 ms) and noise-filled retention intervals (0 to 480 ms). With a 0-ms delay, performance was near asymptotic with the 30-ms tone, but the memory of this brief tone suffered a massive decrement at retention intervals as brief as 60 ms; in contrast, memory for the 340-ms tone was stable for at least 240 ms. If the retention interval was filled by band-stop noise (with targets presented in the spectral gap), then the rat's memory for brief tones was superior to that obtained with the standard broad-band noise filler, and band-stop noise was better than a band-pass noise that had the tones embedded in the region of its spectral energy. These findings are consistent with the hypotheses that auditory memory in the rat consists of a transient sensorylike echoic store and a short-term store more resistant to the effects of retroactive interference.

  8. Difference equation model for isothermal gas chromatography expresses retention behavior of homologues of n-alkanes excluding the influence of holdup time

    Science.gov (United States)

    Wu, Liejun; Chen, Yongli; Caccamise, Sarah A.L.; Li, Qing X.

    2012-01-01

    A difference equation (DE) model is developed using the methylene retention increment (Δtz) of n-alkanes to avoid the influence of gas holdup time (tM). The effects of the equation orders (1st–5th) on the accuracy of a curve fitting show that a linear equation (LE) is less satisfactory and it is not necessary to use a complicated cubic or higher order equation. The relationship between the logarithm of Δtz and the carbon number (z) of the n-alkanes under isothermal conditions closely follows the quadratic equation for C3–C30 n-alkanes at column temperatures of 24–260 °C. The first and second order forward differences of the expression (Δlog Δtz and Δ2log Δtz, respectively) are linear and constant, respectively, which validates the DE model. This DE model lays a necessary foundation for further developing a retention model to accurately describe the relationship between the adjusted retention time and z of n-alkanes. PMID:22939376

  9. A retention-time-shift-tolerant background subtraction and noise reduction algorithm (BgS-NoRA) for extraction of drug metabolites in liquid chromatography/mass spectrometry data from biological matrices.

    Science.gov (United States)

    Zhu, Peijuan; Ding, Wei; Tong, Wei; Ghosal, Anima; Alton, Kevin; Chowdhury, Swapan

    2009-06-01

    A retention-time-shift-tolerant background subtraction and noise reduction algorithm (BgS-NoRA) is implemented using the statistical programming language R to remove non-drug-related ion signals from accurate mass liquid chromatography/mass spectrometry (LC/MS) data. The background-subtraction part of the algorithm is similar to a previously published procedure (Zhang H and Yang Y. J. Mass Spectrom. 2008, 43: 1181-1190). The noise reduction algorithm (NoRA) is an add-on feature to help further clean up the residual matrix ion noises after background subtraction. It functions by removing ion signals that are not consistent across many adjacent scans. The effectiveness of BgS-NoRA was examined in biological matrices by spiking blank plasma extract, bile and urine with diclofenac and ibuprofen that have been pre-metabolized by microsomal incubation. Efficient removal of background ions permitted the detection of drug-related ions in in vivo samples (plasma, bile, urine and feces) obtained from rats orally dosed with (14)C-loratadine with minimal interference. Results from these experiments demonstrate that BgS-NoRA is more effective in removing analyte-unrelated ions than background subtraction alone. NoRA is shown to be particularly effective in the early retention region for urine samples and middle retention region for bile samples, where the matrix ion signals still dominate the total ion chromatograms (TICs) after background subtraction. In most cases, the TICs after BgS-NoRA are in excellent qualitative correlation to the radiochromatograms. BgS-NoRA will be a very useful tool in metabolite detection and identification work, especially in first-in-human (FIH) studies and multiple dose toxicology studies where non-radio-labeled drugs are administered. Data from these types of studies are critical to meet the latest FDA guidance on Metabolite in Safety Testing (MIST). Copyright (c) 2009 John Wiley & Sons, Ltd.

  10. Study of thermal behavior of vitamin D3 by pyrolysis-GC-MS in combination with boiling point-retention time correlation.

    Science.gov (United States)

    Sun, Yu'an; Liu, Baoxia; Wang, Guoqing; Zhang, Rongjie; Xie, Bing

    2005-01-01

    The thermal behavior of vitamin D3 was studied based on pyrolysis-GC-MS technique. It was pyrolyzed at 600 degrees C, 750 degrees C, 900 degrees C, respectively. The pyrolysis product were separated With an HP-5 column and identified by the NIST mass spectral search program in combination with the correlation of boiling point and retention time (BP-RT). There are totally 50 components, including mono aromatics and polycyclic aromatic hydrocarbons (PAHs), were determined. It is shown that the contents of the PAHs are increasing with the increasing of the pyrolysis temperature. The contents of the determined components vary from 0.04% to 37.08%.

  11. Prediction of collision cross section and retention time for broad scope screening in gradient reversed-phase liquid chromatography-ion mobility-high resolution accurate mass spectrometry

    DEFF Research Database (Denmark)

    Mollerup, Christian Brinch; Mardal, Marie; Dalsgaard, Petur Weihe

    2018-01-01

    artificial neural networks (ANNs). Prediction was based on molecular descriptors, 827 RTs, and 357 CCS values from pharmaceuticals, drugs of abuse, and their metabolites. ANN models for the prediction of RT or CCS separately were examined, and the potential to predict both from a single model......Exact mass, retention time (RT), and collision cross section (CCS) are used as identification parameters in liquid chromatography coupled to ion mobility high resolution accurate mass spectrometry (LC-IM-HRMS). Targeted screening analyses are now more flexible and can be expanded for suspect...

  12. Assessment of the heterogeneous ruminal fiber pool and development of a mathematical approach for predicting the mean retention time of feeds in goats.

    Science.gov (United States)

    Regadas Filho, J G L; Tedeschi, L O; Vieira, R A M; Rodrigues, M T

    2014-03-01

    The objectives of this study were to evaluate ruminal fiber stratification and to develop a mathematical approach for predicting the mean retention time (MRT) of forage and concentrates in goats. A dataset from 3 studies was used that contained information regarding fiber and lignin intake as well as ruminal content and the kinetics of fiber passage for forage and concentrates. The kinetic information was obtained through pulse dose and the fecal concentration measurement of forage and concentrate markers in the same animals that were used to measure ruminal content. The evaluation of heterogeneous fiber pools in the rumen was performed using the Lucas' test assumptions, and the marker excretion profiles were interpreted using a model known in the literature as GNG1. The GNG1 model assumes an age-dependent fractional rate for the transfer of particles from the raft to the escapable pool in the rumen (λ(r); h(-1)) and an age-independent fractional rate for the escape of particles from the escapable pool to the remaining parts of the stomach (k(e); h(-1)). The equations used to predict the MRT for forage and concentrate fiber were developed using stepwise regression. A sensitivity analysis was conducted using a Monte Carlo simulation to investigate the relationships between the dependent and independent variables and between forage and concentrate passage rates. The Lucas' test yields goodness-of-fit estimates for NDF analysis; however, the homogeneous fiber pool approach could not be applied because a positive intercept (P ruminal content. The stepwise regression model for MRT estimation had an approximate coefficient of determination and a root mean square error (RMSE) for forage of 0.53 and 9.78 h, respectively, and for concentrate of 0.49 and 5.86 h, respectively. The sensitivity analysis yielded a mean rate of passage (k(p)) value for forage of 0.0322 h(-1) (0.0158 to 0.0556 h(-1)) with 99% confidence interval. For the concentrate, the mean k(p) value was of 0

  13. A seasonal comparison of deposition velocities and retention half-times for Cs-134 and Ce-141 on cool desert vegetation

    International Nuclear Information System (INIS)

    Millard, Gloria C.; Fraley, Leslie Jr.; Markham, O.D.

    1978-01-01

    Due to a scarcity of reliable deposition velocity estimates for radionuclides (particularly those in the submicron range) pooled estimates have been used to predict population doses resulting from atmospheric releases of radioactive particulates. The use of these estimates has led to large uncertainties in whole body dose estimates. Deposition velocities and retention half-times were therefore determined for submicron aerosols of 141 Ce (biologically inactive) and 134 Cs (biologically active) on sagebrush dominated desert vegetation in SE Idaho. Approximately 250 mCi (9.3 GBq) of each radionuclide were released over stands of Artemisia tridentata (big sagebrush) and bottlebrush grass (Sitanion hystrix) during three stages of plant development - spring vegetative growth, seed development, and plant dormancy. Air filters and vegetation samples were collected immediately following each release for use in deposition velocity calculations. Vegetation sampling was continued for a period of three months to obtain retention data. Deposition velocity values were 0.20 cm/s for sagebrush and 0.025 cm/s for grass. The loss of activity on the vegetation seemed to best fit a two component exponential loss function. Short component half-times were 1 to 2 days for both species. Long component half-times were two to three weeks for the shrub species and one to two weeks for the grass species. No significant difference was observed between nuclides. (author)

  14. American Recovery and Reinvestment Act of 2009. Interim Report on Customer Acceptance, Retention, and Response to Time-Based Rates from the Consumer Behavior Studies

    Energy Technology Data Exchange (ETDEWEB)

    Cappers, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hans, Liesel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Scheer, Richard [Scheer Ventures, Takoma Park, MD (United States)

    2015-06-01

    Time-based rate programs1, enabled by utility investments in advanced metering infrastructure (AMI), are increasingly being considered by utilities as tools to reduce peak demand and enable customers to better manage consumption and costs. There are several customer systems that are relatively new to the marketplace and have the potential for improving the effectiveness of these programs, including in-home displays (IHDs), programmable communicating thermostats (PCTs), and web portals. Policy and decision makers are interested in more information about customer acceptance, retention, and response before moving forward with expanded deployments of AMI-enabled new rates and technologies. Under the Smart Grid Investment Grant Program (SGIG), the U.S. Department of Energy (DOE) partnered with several utilities to conduct consumer behavior studies (CBS). The goals involved applying randomized and controlled experimental designs for estimating customer responses more precisely and credibly to advance understanding of time-based rates and customer systems, and provide new information for improving program designs, implementation strategies, and evaluations. The intent was to produce more robust and credible analysis of impacts, costs, benefits, and lessons learned and assist utility and regulatory decision makers in evaluating investment opportunities involving time-based rates. To help achieve these goals, DOE developed technical guidelines to help the CBS utilities estimate customer acceptance, retention, and response more precisely.

  15. Searching for Contracting Patterns over Time: Do Prime Contractor and Subcontractor Relations Follow Similar Patterns for Professional Services Provision?

    Science.gov (United States)

    Ponomariov, Branco; Kingsley, Gordon; Boardman, Craig

    2011-01-01

    This paper compares over a 12-year period (1) patterns of contracting between a state transportation agency and its prime contractors providing engineering design services with (2) patterns between these prime contractors and their subcontractors. We find evidence of different contracting patterns at each level that emerge over time and coexist in…

  16. Enhancement of anaerobic acidogenesis by integrating an electrochemical system into an acidogenic reactor: effect of hydraulic retention times (HRT) and role of bacteria and acidophilic methanogenic Archaea.

    Science.gov (United States)

    Zhang, Jingxin; Zhang, Yaobin; Quan, Xie; Chen, Shuo

    2015-03-01

    In this study, an acidogenic reactor packed with a pair of Fe-carbon electrodes (R1) was developed to enhance anaerobic acidogenesis of organic wastewater at short hydraulic retention times. The results indicated that the acidogenic efficiency was improved by settling a bio-electrochemical system. When hydraulic retention times decreased from 12 to 3h, R1 showed 18.9% more chemical oxygen demand removal and 13.8% more acidification efficiency. After cutting off the voltage of R1, the COD removal decreased by about 5%. Coupling of Fe(2+) leaching and electric field accelerated the hydrolysis of polysaccharide, relieving its accumulation in the sludge phase. Several acidophilic methanogenic Archaea such as Methanosarcina sp. were enriched in R1, which was favorable for consuming organic acids and preventing excessive pH decline. Thus, the developed acidogenic reactor with Fe-carbon electrodes is expected to be potentially effective and useful for wastewater treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Rapid determination of thermodynamic parameters from one-dimensional programmed-temperature gas chromatography for use in retention time prediction in comprehensive multidimensional chromatography.

    Science.gov (United States)

    McGinitie, Teague M; Ebrahimi-Najafabadi, Heshmatollah; Harynuk, James J

    2014-01-17

    A new method for estimating the thermodynamic parameters of ΔH(T0), ΔS(T0), and ΔCP for use in thermodynamic modeling of GC×GC separations has been developed. The method is an alternative to the traditional isothermal separations required to fit a three-parameter thermodynamic model to retention data. Herein, a non-linear optimization technique is used to estimate the parameters from a series of temperature-programmed separations using the Nelder-Mead simplex algorithm. With this method, the time required to obtain estimates of thermodynamic parameters a series of analytes is significantly reduced. This new method allows for precise predictions of retention time with the average error being only 0.2s for 1D separations. Predictions for GC×GC separations were also in agreement with experimental measurements; having an average relative error of 0.37% for (1)tr and 2.1% for (2)tr. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time.

    Science.gov (United States)

    Esparza-Soto, M; Arzate-Archundia, O; Solís-Morelos, C; Fall, C

    2013-01-01

    The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 ± 0.6 °C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m(3)/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 ± 0.3 h). The CODsol removal efficiency was low (59-78%). The measured biogas production increased from 240 ± 54 to 431 ± 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m(3) of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700-4,800 mg/L) and high effluent VSS (177-313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater.

  19. Transit ridership, reliability, and retention.

    Science.gov (United States)

    2008-10-01

    This project explores two major components that affect transit ridership: travel time reliability and rider : retention. It has been recognized that transit travel time reliability may have a significant impact on : attractiveness of transit to many ...

  20. A similarity solution of time dependent MHD liquid film flow over stretching sheet with variable physical properties

    Directory of Open Access Journals (Sweden)

    M. Idrees

    2018-03-01

    Full Text Available An analysis is performed for the fluid dynamics incorporating the variation of viscosity and thermal conductivity on an unsteady two-dimensional free surface flow of a viscous incompressible conducting fluid taking into account the effect of a magnetic field. Surface tension quadratically vary with temperature while fluid viscosity and thermal conductivity are assumed to vary as a linear function of temperature. The boundary layer partial differential equations in cartesian coordinates are transformed into a system of nonlinear ordinary differential equations (ODEs by similarity transformation. The developed nonlinear equations are solved analytically by Homotopy Analysis Method (HAM while numerically by using the shooting method. The Effects of natural parameters such as the variable viscosity parameter A, variable thermal conductivity parameter N, Hartmann number Ma, film Thickness, unsteadiness parameter S, Thermocapillary number M and Prandtl number Pr on the velocity and temperature profiles are investigated. The results for the surface skin friction coefficient f″(0, Nusselt number (heat flux -θ′(0 and free surface temperature θ(1 are presented graphically and in tabular form. Keywords: Variable viscosity and thermal conductivity, Thermocapillary number, Magnetic field, Thin film, Unsteady stretching surface

  1. A similarity solution of time dependent MHD liquid film flow over stretching sheet with variable physical properties

    Science.gov (United States)

    Idrees, M.; Rehman, Sajid; Shah, Rehan Ali; Ullah, M.; Abbas, Tariq

    2018-03-01

    An analysis is performed for the fluid dynamics incorporating the variation of viscosity and thermal conductivity on an unsteady two-dimensional free surface flow of a viscous incompressible conducting fluid taking into account the effect of a magnetic field. Surface tension quadratically vary with temperature while fluid viscosity and thermal conductivity are assumed to vary as a linear function of temperature. The boundary layer partial differential equations in cartesian coordinates are transformed into a system of nonlinear ordinary differential equations (ODEs) by similarity transformation. The developed nonlinear equations are solved analytically by Homotopy Analysis Method (HAM) while numerically by using the shooting method. The Effects of natural parameters such as the variable viscosity parameter A, variable thermal conductivity parameter N, Hartmann number Ma, film Thickness, unsteadiness parameter S, Thermocapillary number M and Prandtl number Pr on the velocity and temperature profiles are investigated. The results for the surface skin friction coefficient f″ (0) , Nusselt number (heat flux) -θ‧ (0) and free surface temperature θ (1) are presented graphically and in tabular form.

  2. Similarity recognition of online data curves based on dynamic spatial time warping for the estimation of lithium-ion battery capacity

    Science.gov (United States)

    Tao, Laifa; Lu, Chen; Noktehdan, Azadeh

    2015-10-01

    Battery capacity estimation is a significant recent challenge given the complex physical and chemical processes that occur within batteries and the restrictions on the accessibility of capacity degradation data. In this study, we describe an approach called dynamic spatial time warping, which is used to determine the similarities of two arbitrary curves. Unlike classical dynamic time warping methods, this approach can maintain the invariance of curve similarity to the rotations and translations of curves, which is vital in curve similarity search. Moreover, it utilizes the online charging or discharging data that are easily collected and do not require special assumptions. The accuracy of this approach is verified using NASA battery datasets. Results suggest that the proposed approach provides a highly accurate means of estimating battery capacity at less time cost than traditional dynamic time warping methods do for different individuals and under various operating conditions.

  3. Robust estimation of thermodynamic parameters (ΔH, ΔS and ΔCp) for prediction of retention time in gas chromatography - Part II (Application).

    Science.gov (United States)

    Claumann, Carlos Alberto; Wüst Zibetti, André; Bolzan, Ariovaldo; Machado, Ricardo A F; Pinto, Leonel Teixeira

    2015-12-18

    For this work, an analysis of parameter estimation for the retention factor in GC model was performed, considering two different criteria: sum of square error, and maximum error in absolute value; relevant statistics are described for each case. The main contribution of this work is the implementation of an initialization scheme (specialized) for the estimated parameters, which features fast convergence (low computational time) and is based on knowledge of the surface of the error criterion. In an application to a series of alkanes, specialized initialization resulted in significant reduction to the number of evaluations of the objective function (reducing computational time) in the parameter estimation. The obtained reduction happened between one and two orders of magnitude, compared with the simple random initialization. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Effect of sludge retention time on the biological performance of anaerobic membrane bioreactors treating corn-to-ethanol thin stillage with high lipid content.

    Science.gov (United States)

    Dereli, Recep Kaan; van der Zee, Frank P; Heffernan, Barry; Grelot, Aurelie; van Lier, Jules B

    2014-02-01

    The potential of anaerobic membrane bioreactors (AnMBRs) for the treatment of lipid rich corn-to-ethanol thin stillage was investigated at three different sludge retention times (SRT), i.e. 20, 30 and 50 days. The membrane assisted biomass retention in AnMBRs provided an excellent solution to sludge washout problems reported for the treatment of lipid rich wastewaters by granular sludge bed reactors. The AnMBRs achieved high COD removal efficiencies up to 99% and excellent effluent quality. Although higher organic loading rates (OLRs) up to 8.0 kg COD m(-3) d(-1) could be applied to the reactors operated at shorter SRTs, better biological degradation efficiencies, i.e. up to 83%, was achieved at increased SRTs. Severe long chain fatty acid (LCFA) inhibition was observed at 50 days SRT, possibly caused by the extensive dissolution of LCFA in the reactor broth, inhibiting the methanogenic biomass. Physicochemical mechanisms such as precipitation with divalent cations and adsorption on the sludge played an important role in the occurrence of LCFA removal, conversion, and inhibition. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Reduction of the hydraulic retention time at constant high organic loading rate to reach the microbial limits of anaerobic digestion in various reactor systems.

    Science.gov (United States)

    Ziganshin, Ayrat M; Schmidt, Thomas; Lv, Zuopeng; Liebetrau, Jan; Richnow, Hans Hermann; Kleinsteuber, Sabine; Nikolausz, Marcell

    2016-10-01

    The effects of hydraulic retention time (HRT) reduction at constant high organic loading rate on the activity of hydrogen-producing bacteria and methanogens were investigated in reactors digesting thin stillage. Stable isotope fingerprinting was additionally applied to assess methanogenic pathways. Based on hydA gene transcripts, Clostridiales was the most active hydrogen-producing order in continuous stirred tank reactor (CSTR), fixed-bed reactor (FBR) and anaerobic sequencing batch reactor (ASBR), but shorter HRT stimulated the activity of Spirochaetales. Further decreasing HRT diminished Spirochaetales activity in systems with biomass retention. Based on mcrA gene transcripts, Methanoculleus and Methanosarcina were the predominantly active in CSTR and ASBR, whereas Methanosaeta and Methanospirillum activity was more significant in stably performing FBR. Isotope values indicated the predominance of aceticlastic pathway in FBR. Interestingly, an increased activity of Methanosaeta was observed during shortening HRT in CSTR and ASBR despite high organic acids concentrations, what was supported by stable isotope data. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Identification and Sensitivity Analysis for Average Causal Mediation Effects with Time-Varying Treatments and Mediators: Investigating the Underlying Mechanisms of Kindergarten Retention Policy.

    Science.gov (United States)

    Park, Soojin; Steiner, Peter M; Kaplan, David

    2018-06-01

    Considering that causal mechanisms unfold over time, it is important to investigate the mechanisms over time, taking into account the time-varying features of treatments and mediators. However, identification of the average causal mediation effect in the presence of time-varying treatments and mediators is often complicated by time-varying confounding. This article aims to provide a novel approach to uncovering causal mechanisms in time-varying treatments and mediators in the presence of time-varying confounding. We provide different strategies for identification and sensitivity analysis under homogeneous and heterogeneous effects. Homogeneous effects are those in which each individual experiences the same effect, and heterogeneous effects are those in which the effects vary over individuals. Most importantly, we provide an alternative definition of average causal mediation effects that evaluates a partial mediation effect; the effect that is mediated by paths other than through an intermediate confounding variable. We argue that this alternative definition allows us to better assess at least a part of the mediated effect and provides meaningful and unique interpretations. A case study using ECLS-K data that evaluates kindergarten retention policy is offered to illustrate our proposed approach.

  7. Suspect screening of large numbers of emerging contaminants in environmental waters using artificial neural networks for chromatographic retention time prediction and high resolution mass spectrometry data analysis.

    Science.gov (United States)

    Bade, Richard; Bijlsma, Lubertus; Miller, Thomas H; Barron, Leon P; Sancho, Juan Vicente; Hernández, Felix

    2015-12-15

    The recent development of broad-scope high resolution mass spectrometry (HRMS) screening methods has resulted in a much improved capability for new compound identification in environmental samples. However, positive identifications at the ng/L concentration level rely on analytical reference standards for chromatographic retention time (tR) and mass spectral comparisons. Chromatographic tR prediction can play a role in increasing confidence in suspect screening efforts for new compounds in the environment, especially when standards are not available, but reliable methods are lacking. The current work focuses on the development of artificial neural networks (ANNs) for tR prediction in gradient reversed-phase liquid chromatography and applied along with HRMS data to suspect screening of wastewater and environmental surface water samples. Based on a compound tR dataset of >500 compounds, an optimized 4-layer back-propagation multi-layer perceptron model enabled predictions for 85% of all compounds to within 2min of their measured tR for training (n=344) and verification (n=100) datasets. To evaluate the ANN ability for generalization to new data, the model was further tested using 100 randomly selected compounds and revealed 95% prediction accuracy within the 2-minute elution interval. Given the increasing concern on the presence of drug metabolites and other transformation products (TPs) in the aquatic environment, the model was applied along with HRMS data for preliminary identification of pharmaceutically-related compounds in real samples. Examples of compounds where reference standards were subsequently acquired and later confirmed are also presented. To our knowledge, this work presents for the first time, the successful application of an accurate retention time predictor and HRMS data-mining using the largest number of compounds to preliminarily identify new or emerging contaminants in wastewater and surface waters. Copyright © 2015 Elsevier B.V. All rights

  8. The effect of solids retention times on the characterization of extracellular polymeric substances and soluble microbial products in a submerged membrane bioreactor.

    Science.gov (United States)

    Duan, Liang; Song, Yonghui; Yu, Huibin; Xia, Siqing; Hermanowicz, Slawomir W

    2014-07-01

    In this study, the effect of solids retention times (SRTs) on extracellular polymeric substances (EPS) and soluble microbial products (SMPs) were investigated in a membrane bioreactor (MBR) at SRTs of 10, 5 and 3 days. The results showed that more carbohydrates and proteins were accumulated at short SRT, which can due to the higher biomass activity in the reactor. The molecular weight (MW) distribution analysis suggested that macromolecules (MW>30 kDa) and small molecules (MW<1 kDa) were the dominant fraction of EPS and SMP, respectively. The reactor at shorter SRT had more small molecules and less macromolecules of carbohydrates. The MW distribution of total organic carbon (TOC) suggested that other organic moieties were exuded by microbes into the solution. The shorter SRT had more undefined microbial by-product-like substances and different O − H bonds in hydroxyl functional groups. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Influence of sludge retention time on tolerance of copper toxicity for polyphosphate accumulating organisms linked to polyhydroxyalkanoates metabolism and phosphate removal.

    Science.gov (United States)

    Tsai, Yung-Pin; Chen, Hsiu-Ting

    2011-12-01

    This study explored the influence of sludge retention time (SRT) on tolerance of copper invasion for polyphosphate accumulating organisms (PAOs) in an enhanced biological phosphorus removal (EBPR). The experimental data showed the anaerobic polyhydroxyalkanoates (PHA) storage for the sludge at 10d SRT was less influenced by copper invasion than those at 5d and 15d SRTs. The reaction of PAOs aerobically taking up phosphate for the sludge at 5d or 15d SRT almost ceased at 2 mg Cu L(-1), whereas PAOs in the sludge at 10d SRT retained half of the ability to take up phosphate. Both the PHAs degradation and synthesis rates decreased with increasing copper concentration, regardless of the SRTs. However, the copper inhibition of the former was greater than that of the later. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Cationic PLGA/Eudragit RL nanoparticles for increasing retention time in synovial cavity after intra-articular injection in knee joint

    Directory of Open Access Journals (Sweden)

    Kim SR

    2015-08-01

    Full Text Available Sung Rae Kim,1 Myoung Jin Ho,2 Eugene Lee,3 Joon Woo Lee,3 Young Wook Choi,1 Myung Joo Kang21College of Pharmacy, Chung-Ang University, Dongjak-gu, Seoul, 2College of Pharmacy, Dankook University, Dongnam-gu, Cheonan, Chungnam, 3Department of Radiology, Seoul National University Bundang Hospital, Bundang-gu, Seongnam, Gyeonggi-do, South KoreaAbstract: Positively surface-charged poly(lactide-co-glycolide (PLGA/Eudragit RL nanoparticles (NPs were designed to increase retention time and sustain release profile in joints after intra-articular injection, by forming micrometer-sized electrostatic aggregates with hyaluronic acid, an endogenous anionic polysaccharide found in high amounts in synovial fluid. The cationic NPs consisting of PLGA, Eudragit RL, and polyvinyl alcohol were fabricated by solvent evaporation technique. The NPs were 170.1 nm in size, with a zeta potential of 21.3 mV in phosphate-buffered saline. Hyperspectral imaging (CytoViva® revealed the formation of the micrometer-sized filamentous aggregates upon admixing, due to electrostatic interaction between NPs and the polysaccharides. NPs loaded with a fluorescent probe (1,1'-dioctadecyl-3,3,3',3' tetramethylindotricarbocyanine iodide, DiR displayed a significantly improved retention time in the knee joint, with over 50% preservation of the fluorescent signal 28 days after injection. When DiR solution was injected intra-articularly, the fluorescence levels rapidly decreased to 30% of the initial concentration within 3 days in mice. From these findings, we suggest that PLGA-based cationic NPs could be a promising tool for prolonged delivery of therapeutic agents in joints selectively.Keywords: PLGA, Eudragit RL, hyaluronic acid, cationic nanoparticles, intra-articular injection, electrostatic interaction

  11. Removal of antibiotics in wastewater: Effect of hydraulic and solid retention times on the fate of tetracycline in the activated sludge process.

    Science.gov (United States)

    Kim, Sungpyo; Eichhorn, Peter; Jensen, James N; Weber, A Scott; Aga, Diana S

    2005-08-01

    A study was conducted to examine the influence of hydraulic retention time (HRT) and solid retention time (SRT) on the removal of tetracycline in the activated sludge processes. Two lab-scale sequencing batch reactors (SBRs) were operated to simulate the activated sludge process. One SBR was spiked with 250 microg/L tetracycline, while the other SBR was evaluated at tetracycline concentrations found in the influent of the wastewater treatment plant (WWTP) where the activated sludge was obtained. The concentrations of tetracyclines in the influent of the WWTP ranged from 0.1 to 0.6 microg/L. Three different operating conditions were applied during the study (phase 1-HRT: 24 h and SRT: 10 days; phase 2-HRT: 7.4 h and SRT: 10 days; and phase 3-HRT: 7.4 h and SRT: 3 days). The removal efficiency of tetracycline in phase 3 (78.4 +/- 7.1%) was significantly lower than that observed in phase 1 (86.4 +/- 8.7%) and phase 2 (85.1 +/- 5.4%) at the 95% confidence level. The reduction of SRT in phase 3 while maintaining a constant HRT decreased tetracycline removal efficiency. Sorption kinetics reached equilibrium within 24 h. Batch equilibrium experiments yielded an adsorption coefficient (Kads) of 8400 +/- 500 mL/g and a desorption coefficient (Kdes) of 22 600 +/- 2200 mL/g. No evidence of biodegradation for tetracycline was observed during the biodegradability test, and sorption was found to be the principal removal mechanism of tetracycline in activated sludge.

  12. Intramuscular Administration of Drotaverine Hydrochloride Decreases Both Incidence of Urinary Retention and Time to Micturition in Orthopedic Patients under Spinal Anesthesia: A Single Blinded Randomized Study

    Directory of Open Access Journals (Sweden)

    Dariusz Tomaszewski

    2015-01-01

    Full Text Available Purpose. Postoperative urinary retention (POUR increases the duration of hospitalization and frequency and risk of urinary bladder catheterization. The objective of this study was to analyze the efficacy of intramuscularly administered drotaverine hydrochloride in the prevention of POUR in orthopedic patients. Methods. Two hundred and thirty patients 17–40 years of age undergoing lower limb orthopedic procedures under spinal anesthesia were enrolled in the study. The study group received 40 mg of drotaverine hydrochloride intramuscularly; the second group was the control. The main outcome measure was (1 the time to micturition and (2 the incidence of urinary bladder catheterization and time to catheterization. Results. Two hundred and one patients of 230 enrolled participants completed the study. Compared to the control group, the male patients in study group exhibited a shorter time to spontaneous micturition (441 versus 563 minutes, 95% CI of the difference of means between 39 and 205 minutes and a lower incidence of urinary bladder catheterization (4/75 versus 10/54 (RR 0.29, 95% CI: 0.1–0.87; P=0.0175. Conclusions. Intramuscular administration of drotaverine hydrochloride decreased the time to spontaneous micturition and decreased the incidence of urinary bladder catheterization in male patients who underwent orthopedic surgery under spinal anesthesia. This trial is registered with NCT02026427.

  13. Recruitment and Retention of Full-Time Engineering Faculty, Fall 1980. Higher Education Panel Report Number 52.

    Science.gov (United States)

    Atelsek, Frank J.; Gomberg, Irene L.

    The extent of faculty vacancies in colleges of engineering, the effects of such vacancies upon research and instructional programs, and the nature of the competition between academia and industry in hiring engineering faculty were surveyed. The focus is on permanent full-time faculty positions in the following major engineering fields:…

  14. Time evolution of the general characteristics and Cu retention capacity in an acid soil amended with a bentonite winery waste

    DEFF Research Database (Denmark)

    Fernandez Calviño, David; Rodríguez-Salgado, Isabel; Pérez-Rodríguez, Paula

    2015-01-01

    The effect of bentonite waste added to a "poor" soil on its general characteristic and copper adsorption capacity was assessed. The soil was amended with different bentonite waste concentrations (0, 10, 20, 40 and 80Mgha-1) in laboratory pots, and different times of incubation of samples were tes...

  15. Acidity-Triggered Tumor Retention/Internalization of Chimeric Peptide for Enhanced Photodynamic Therapy and Real-Time Monitoring of Therapeutic Effects.

    Science.gov (United States)

    Han, Kai; Zhang, Wei-Yun; Ma, Zhao-Yu; Wang, Shi-Bo; Xu, Lu-Ming; Liu, Jia; Zhang, Xian-Zheng; Han, He-You

    2017-05-17

    Photodynamic therapy (PDT) holds great promise in tumor treatment. Nevertheless, it remains highly desirable to develop easy-to-fabricated PDT systems with improved tumor accumulation/internalization and timely therapeutic feedback. Here, we report a tumor-acidity-responsive chimeric peptide for enhanced PDT and noninvasive real-time apoptosis imaging. Both in vitro and in vivo studies revealed that a tumor mildly acidic microenvironment could trigger rapid protonation of carboxylate anions in chimeric peptide, which led to increased ζ potential, improved hydrophobicity, controlled size enlargement, and precise morphology switching from sphere to spherocylinder shape of the chimeric peptide. All of these factors realized superfast accumulation and prolonged retention in the tumor region, selective cellular internalization, and enhanced PDT against the tumor. Meanwhile, this chimeric peptide could further generate reactive oxygen species and initiate cell apoptosis during PDT. The subsequent formation of caspase-3 enzyme hydrolyzed the chimeric peptide, achieving a high signal/noise ratio and timely fluorescence feedback. Importantly, direct utilization of the acidity responsiveness of a biofunctional Asp-Glu-Val-Asp-Gly (DEVDG, caspase-3 enzyme substrate) peptide sequence dramatically simplified the preparation and increased the performance of the chimeric peptide furthest.

  16. Soil Water Retention Curve

    Science.gov (United States)

    Johnson, L. E.; Kim, J.; Cifelli, R.; Chandra, C. V.

    2016-12-01

    Potential water retention, S, is one of parameters commonly used in hydrologic modeling for soil moisture accounting. Physically, S indicates total amount of water which can be stored in soil and is expressed in units of depth. S can be represented as a change of soil moisture content and in this context is commonly used to estimate direct runoff, especially in the Soil Conservation Service (SCS) curve number (CN) method. Generally, the lumped and the distributed hydrologic models can easily use the SCS-CN method to estimate direct runoff. Changes in potential water retention have been used in previous SCS-CN studies; however, these studies have focused on long-term hydrologic simulations where S is allowed to vary at the daily time scale. While useful for hydrologic events that span multiple days, the resolution is too coarse for short-term applications such as flash flood events where S may not recover its full potential. In this study, a new method for estimating a time-variable potential water retention at hourly time-scales is presented. The methodology is applied for the Napa River basin, California. The streamflow gage at St Helena, located in the upper reaches of the basin, is used as the control gage site to evaluate the model performance as it is has minimal influences by reservoirs and diversions. Rainfall events from 2011 to 2012 are used for estimating the event-based SCS CN to transfer to S. As a result, we have derived the potential water retention curve and it is classified into three sections depending on the relative change in S. The first is a negative slope section arising from the difference in the rate of moving water through the soil column, the second is a zero change section representing the initial recovery the potential water retention, and the third is a positive change section representing the full recovery of the potential water retention. Also, we found that the soil water moving has traffic jam within 24 hours after finished first

  17. Estimating serial correlation and self-similarity in financial time series-A diversification approach with applications to high frequency data

    Science.gov (United States)

    Gerlich, Nikolas; Rostek, Stefan

    2015-09-01

    We derive a heuristic method to estimate the degree of self-similarity and serial correlation in financial time series. Especially, we propagate the use of a tailor-made selection of different estimation techniques that are used in various fields of time series analysis but until now have not consequently found their way into the finance literature. Following the idea of portfolio diversification, we show that considerable improvements with respect to robustness and unbiasedness can be achieved by using a basket of estimation methods. With this methodological toolbox at hand, we investigate real market data to show that noticeable deviations from the assumptions of constant self-similarity and absence of serial correlation occur during certain periods. On the one hand, this may shed a new light on seemingly ambiguous scientific findings concerning serial correlation of financial time series. On the other hand, a proven time-changing degree of self-similarity may help to explain high-volatility clusters of stock price indices.

  18. Time evolution of the general characteristics and Cu retention capacity in an acid soil amended with a bentonite winery waste.

    Science.gov (United States)

    Fernández-Calviño, David; Rodríguez-Salgado, Isabel; Pérez-Rodríguez, Paula; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel

    2015-03-01

    The effect of bentonite waste added to a "poor" soil on its general characteristic and copper adsorption capacity was assessed. The soil was amended with different bentonite waste concentrations (0, 10, 20, 40 and 80 Mg ha(-1)) in laboratory pots, and different times of incubation of samples were tested (one day and one, four and eight months). The addition of bentonite waste increased the pH, organic matter content and phosphorus and potassium concentrations in the soil, being stable for P and K, whereas the organic matter decreased with time. Additionally, the copper sorption capacity of the soil and the energy of the Cu bonds increased with bentonite waste additions. However, the use of this type of waste in soil presented important drawbacks for waste dosages higher than 20 Mg ha(-1), such as an excessive increase of the soil pH and an increase of copper in the soil solution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Structure of nitrogen-converting communities induced by hydraulic retention time and COD/N ratio in constantly aerated granular sludge reactors treating digester supernatant.

    Science.gov (United States)

    Cydzik-Kwiatkowska, Agnieszka; Rusanowska, Paulina; Zielińska, Magdalena; Bernat, Katarzyna; Wojnowska-Baryła, Irena

    2014-02-01

    This study investigated how hydraulic retention time (HRT) and COD/N ratio affect nitrogen-converting consortia in constantly aerated granules treating high-ammonium digester supernatant. Three HRTs (10, 13, 19 h) were tested at COD/N ratios of 4.5 and 2.3. Denaturing gradient gel electrophoresis and relative real-time PCR were used to characterize the microbial communities. When changes in HRT and COD/N increased nitrogen loading, the ratio of the relative abundance of aerobic to anaerobic ammonium-oxidizers decreased. The COD/N ratio determined the species composition of the denitrifiers; however, Thiobacillus denitrificans, Pseudomonas denitrificans and Azoarcus sp. showed a high tolerance to the environmental conditions and occurred in the granules from all reactors. Denitrifier genera that support granule formation were identified, such as Pseudomonas, Shinella, and Flavobacterium. In aerated granules, nirK-possessing bacteria were more diverse than nirS-possessing bacteria. At a low COD/N ratio, N2O-reducer diversity increased because of the presence of bacteria known as aerobic denitrifiers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Effect of solids retention time and temperature on waste activated sludge hydrolysis and short-chain fatty acids accumulation under alkaline conditions in continuous-flow reactors.

    Science.gov (United States)

    Feng, Leiyu; Wang, Hua; Chen, Yinguang; Wang, Qin

    2009-01-01

    The effects of solids retention time (SRT) and temperature on waste activated sludge (WAS) hydrolysis and short-chain fatty acids (SCFAs) accumulation were investigated in a series of continuous-flow reactors at pH 10. The experimental results showed that the increase of either SRT or temperature benefited the hydrolysis of WAS and the production of SCFAs. The changes in SRT gave also impact on the percentage of acetic and propionic acids in the fermentative SCFAs, but little influence on that of the slightly long-chain SCFAs, such as n-butyric, iso-butyric, n-valeric and iso-valeric acids. Compared with the control (pH unadjusted) experiment, at SRT of 12d and temperature of 20 degrees C the concentration of SCFAs produced at pH 10 increased from 261.2 to 933.5mg COD/L, and the propionic acid percentage improved from 11.7 to 16.0%. It can be concluded from this investigation that the efficient continuous production of SCFAs at pH 10 is feasible.

  1. Effect of hydraulic retention time and sludge recirculation on greenhouse gas emission and related microbial communities in two-stage membrane bioreactor treating solid waste leachate.

    Science.gov (United States)

    Nuansawan, Nararatchporn; Boonnorat, Jarungwit; Chiemchaisri, Wilai; Chiemchaisri, Chart

    2016-06-01

    Methane (CH4) and nitrous oxide (N2O) emissions and responsible microorganisms during the treatment of municipal solid waste leachate in two-stage membrane bioreactor (MBR) was investigated. The MBR system, consisting of anaerobic and aerobic stages, were operated at hydraulic retention time (HRT) of 5 and 2.5days in each reactor under the presence and absence of sludge recirculation. Organic and nitrogen removals were more than 80% under all operating conditions during which CH4 emission were found highest under no sludge recirculation condition at HRT of 5days. An increase in hydraulic loading resulted in a reduction in CH4 emission from anaerobic reactor but an increase from the aerobic reactor. N2O emission rates were found relatively constant from anaerobic and aerobic reactors under different operating conditions. Diversity of CH4 and N2O producing microorganisms were found decreasing when hydraulic loading rate to the reactors was increased. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Anaerobic mesophilic co-digestion of ensiled sorghum, cheese whey and liquid cow manure in a two-stage CSTR system: Effect of hydraulic retention time.

    Science.gov (United States)

    Dareioti, Margarita Andreas; Kornaros, Michael

    2015-01-01

    The aim of this study was to investigate the effect of hydraulic retention time (HRT) on hydrogen and methane production using a two-stage anaerobic process. Two continuously stirred tank reactors (CSTRs) were used under mesophilic conditions (37°C) in order to enhance acidogenesis and methanogenesis. A mixture of pretreated ensiled sorghum, cheese whey and liquid cow manure (55:40:5, v/v/v) was used. The acidogenic reactor was operated at six different HRTs of 5, 3, 2, 1, 0.75 and 0.5d, under controlled pH5.5, whereas the methanogenic reactor was operated at three HRTs of 24, 16 and 12d. The maximum H2 productivity (2.14L/LRd) and maximum H2 yield (0.70mol H2/mol carbohydrates consumed) were observed at 0.5d HRT. On the other hand, the maximum CH4 production rate of 0.90L/LRd was achieved at HRT of 16d, whereas at lower HRT the process appeared to be inhibited and/or overloaded. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Effect of hydraulic retention time (HRT) on the anaerobic co-digestion of agro-industrial wastes in a two-stage CSTR system.

    Science.gov (United States)

    Dareioti, Margarita Andreas; Kornaros, Michael

    2014-09-01

    A two-stage anaerobic digestion system consisting of two continuously stirred tank reactors (CSTRs) operating at mesophilic conditions (37°C) were used to investigate the effect of hydraulic retention time (HRT) on hydrogen and methane production. The acidogenic reactor was fed with a mixture consisting of olive mill wastewater, cheese whey and liquid cow manure (in a ratio 55:40:5, v/v/v) and operated at five different HRTs (5, 3, 2, 1 and 0.75 d) aiming to evaluate hydrogen productivity and operational stability. The highest system efficiency was achieved at HRT 0.75 d with a maximum hydrogen production rate of 1.72 L/LRd and hydrogen yield of 0.54 mol H2/mol carbohydrates consumed. The methanogenic reactor was operated at HRTs 20 and 25 d with better stability observed at HRT 25 d, whereas accumulation of volatile fatty acids took place at HRT 20 d. The methane production rate at the steady state of HRT 25 d reached 0.33 L CH4/LRd. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Hydraulic retention time affects stable acetate production from tofu processing wastewater in extreme-thermophilic (70°C) mixed culture fermentation.

    Science.gov (United States)

    Chen, Yun; Zhang, Fang; Wang, Ting; Shen, Nan; Yu, Zhong-Wei; Zeng, Raymond J

    2016-09-01

    Acetate is an important industrial chemical and its production from wastes via mixed culture fermentation (MCF) is economic. In this work, the effect of hydraulic retention time (HRT) on acetate production from tofu processing wastewater (TPW) in extreme-thermophilic (70°C) MCF was first investigated. It was found that long HRT (>3days) could lead to less acetate production while stable acetate production was achieved at short HRT (3days) with the yield of 0.57g-COD/g-CODTPW. The microbial community analysis showed that hydrogenotrophic methanogens (mainly Methanothermobacter) occupied up to 90% of archaea at both HRTs of 3 and 5days. However, Coprothermobacter, the main acetate-degraders, decreased from 35.74% to 10.58% of bacteria when HRT decreased from 5 to 3days, supporting the aggravation of syntrophic acetate oxidation in long HRT. This work demonstrated that HRT was a crucial factor to maintain stable acetate production from TPW in extreme-thermophilic MCF. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Effect of mixed liquor volatile suspended solids (MLVSS and hydraulic retention time (HRT on the performance of activated sludge process during the biotreatment of real textile wastewater

    Directory of Open Access Journals (Sweden)

    Kapil Kumar

    2014-03-01

    Full Text Available Adequate information is available on colour and organics removal in batch mode using pure microbial cultures from dye contaminated wastewater. There was a need to develop environment friendly and cost effective treatment technique for actual field conditions. Therefore, the present study was undertaken with an aim to evaluate the potential of acclimatized mixed microbial consortia for the removal of colour and organics from real textile wastewater. Experiments were performed in laboratory scale activated sludge process (ASP unit under steady state condition, varying mixed liquor volatile suspended solids (MLVSS (2500, 3500 and 5000 mg/l and hydraulic retention time (HRT (18, 24 and 36 h. The results showed that decolourization and chemical oxygen demand (COD removal increased with increase in MLVSS and HRT. At 18 h HRT, decolourization was found to be 46, 54 and 67%, which increased to 67, 75 and 90% (36 h HRT at 2500, 3500 and 5000 mg/l MLVSS, respectively. COD removal was found to be 62, 73 and 77% (at 18 h HRT which increased to 77, 85 and 91% (36 h HRT at 2000, 3500 and 5000 mg/l MLVSS, respectively. On the basis of the results obtained in this study suitable treatment techniques can be developed for the treatment of wastewater contaminated with variety of dyes in continuous mode of operation. This shall have the advantage of treatment of larger quantity of wastewater in shorter duration.

  6. Dynamics of Archaeal and Bacterial Communities in Response to Variations of Hydraulic Retention Time in an Integrated Anaerobic Fluidized-Bed Membrane Bioreactor Treating Benzothiazole Wastewater

    Directory of Open Access Journals (Sweden)

    Yue Li

    2018-01-01

    Full Text Available An integrated anaerobic fluidized-bed membrane bioreactor (IAFMBR was investigated to treat synthetic high-strength benzothiazole wastewater (50 mg/L at a hydraulic retention time (HRT of 24, 18, and 12 h. The chemical oxygen demand (COD removal efficiency (from 93.6% to 90.9%, the methane percentage (from 70.9% to 69.27%, and the methane yield (from 0.309 m3 CH4/kg·CODremoved to 0.316 m3 CH4/kg·CODremoved were not affected by decreasing HRTs. However, it had an adverse effect on membrane fouling (decreasing service period from 5.3 d to 3.2 d and benzothiazole removal efficiency (reducing it from 97.5% to 82.3%. Three sludge samples that were collected on day 185, day 240, and day 297 were analyzed using an Illumina® MiSeq platform. It is striking that the dominant genus of archaea was always Methanosaeta despite of HRTs. The proportions of Methanosaeta were 80.6% (HRT 24, 91.9% (HRT 18, and 91.2% (HRT 12. The dominant bacterial genera were Clostridium in proportions of 23.9% (HRT 24, 16.4% (HRT 18, and 15.3% (HRT 12, respectively.

  7. Effects of hydraulic retention time on anaerobic hydrogenation performance and microbial ecology of bioreactors fed with glucose-peptone and starch-peptone

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shiue-Lin; Chao, Yu-Chieh; Wang, Yu-Hsuan; Hsiao, Chia-Jung; Bai, Ming-Der [Department of Environmental Engineering, National Cheng-Kung University, No. 1, University Road, Tainan 701 (China); Whang, Liang-Ming; Wang, Yung-Fu; Cheng, Sheng-Shung [Department of Environmental Engineering, National Cheng-Kung University, No. 1, University Road, Tainan 701 (China); Sustainable Environment Research Center (SERC), National Cheng-Kung University, No. 1, University Road, Tainan 701 (China); Tseng, I.-Cheng [Sustainable Environment Research Center (SERC), National Cheng-Kung University, No. 1, University Road, Tainan 701 (China); Department of Life Science, National Cheng-Kung University, No. 1, University Road, Tainan 701 (China)

    2010-01-15

    This study evaluated anaerobic hydrogenation performance and microbial ecology in bioreactors operated at different hydraulic retention time (HRT) conditions and fed with glucose-peptone (GP) and starch-peptone (SP). The maximum hydrogen production rates for GP- and SP-fed bioreactors were found to be 1247 and 412 mmol-H{sub 2}/L/d at HRT of 2 and 3 h, respectively. At HRT > 8 h, hydrogen consumption due to peptone fermentation could occur and thus reduced hydrogen yield from carbohydrate fermentation. Results of cloning/sequencing and denaturant gradient gel electrophoresis (DGGE) indicated that Clostridium sporogenes and Clostridium celerecrescens were dominant hydrogen-producing bacteria in the GP-fed bioreactor, presumably due to their capability on protein hydrolysis. In the SP-fed bioreactor, Lactobacillus plantarum, Propionispira arboris, and Clostridium butyricum were found to be dominant populations, but the presence of P. arboris at HRT > 3 h might be responsible for a lower hydrogen yield from starch fermentation. As a result, optimizing HRT operation for bioreactors was considered an important asset in order to minimize hydrogen-consuming activities and thus maximize net hydrogen production. The limitation of simple parameters such as butyrate to acetate ratio (B/A ratio) in predicting hydrogen production was recognized in this study for bioreactors fed with multiple substrates. It is suggested that microbial ecology analysis, in addition to chemical analysis, should be performed when complex substrates and mixed cultures are used in hydrogen-producing bioreactors. (author)

  8. Modeling the dynamic volatile fatty acids profiles with pH and hydraulic retention time in an anaerobic baffled reactor during the startup period.

    Science.gov (United States)

    Shi, En; Li, Jianzheng; Leu, Shao-Yuan; Antwi, Philip

    2016-12-01

    To predict the dynamic profiles in volatile fatty acids (VFAs) with pH and hydraulic retention time (HRT) during the startup of a 4-compartment ABR, a mathematical model was constructed by introducing pH and thermodynamic inhibition functions into the biochemical processes derived from the ADM1. The calibration of inhibition parameter for propionate uptake effectively improved the prediction accuracy of VFAs. The developed model could simulate the VFAs profiles very well no matter the observable change of pH or/and HRT. The simulation results indicated that both H 2 -producing acetogenesis and methanogenesis in the ABR would be inhibited with a pH less than 4.61, and the propionate oxidation could be thermodynamically restricted even with a neutral pH. A decreased HRT would enhanced the acidogenesis and H 2 -producing acetogenesis in the first 3 compartments, but no observable increase in effluent VFAs could be found due to the synchronously enhanced methanogenesis in the last compartment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. The Effect of the Hydraulic Retention Time on the Performance of an Ecological Wastewater Treatment System: An Anaerobic Filter with a Constructed Wetland

    Directory of Open Access Journals (Sweden)

    María L. Merino-Solís

    2015-03-01

    Full Text Available This work assesses the performance of a municipal pilot wastewater treatment system employing an up-flow anaerobic filter (UAF followed by a horizontal subsurface constructed wetland (HSSCW. This pilot scale demonstration project was implemented in a zone with subtropical climate in order to protect Lake Chapala from wastewater loads that are discharged by small communities in the Lake’s vicinity. The filters were filled with tezontle as the media for biofilm support and the HSSCW was planted with two ornamental plants species, Canna hybrids and Strelitzia reginae. The experiment evaluated three hydraulic retention times (HRT of 18, 28 and 38 h in the UAF, which corresponds to two, three and four days in HSSCW over 66 weeks. The mean efficiencies found for the complete system were 80% and 90% of BOD, 80% and 86% of COD, 30% and 33% of Ntot and between 24% and 44% of Ptot. It was possible to remove almost 80% of organic matter in 18 h in the UAF while the HSSCW reached 30% of removal for Ntot in a HRT of three days. As expected, the UAF was responsible for removing most of the organic matter and the HSSCW removed most of the nitrogen.

  10. Distribution of sulfonamides in liquid and solid anaerobic digestates: effects of hydraulic retention time and swine manure to rice straw ratio.

    Science.gov (United States)

    Jin, Hongmei; Xu, Caiyun; Du, Jing; Wu, Huashan; Huang, Hongying; Chang, Zhizhou; Xu, Yueding; Zhou, Lixiang

    2017-02-01

    The effects of hydraulic retention time (20 and 15 days) and swine manure to rice straw ratios on distribution of sulfonamides (SAs) in liquid and solid anaerobic digestates were studied using bench-scale completely stirred tank reactors at (37 ± 1) °C. Results showed that anaerobic digestion (AD) treatment exhibited a good removal effect on sulfadiazine (SDZ), sulfadimidine (SM2) and sulfachloropyridazine (SCP), especially at HRT = 20 days and co-digestion with swine manure and rice straw. The removal rates of SDZ and SM2 were more than 90%, but only 72.8% for SCP. The residual SAs were mainly remained in solid digestates, with residual rates ranging from 28.8% to 71.3%, 40.6% to 88.0, and 82.7% to 97.0% for SDZ, SM2 and SCP, respectively. Due to lower pKa and higher log K ow of SCP, its residue in solid digestates was far more than SDZ and SM2. Higher HRT and co-digestion could improve the degradation of SAs, which can also be put down to the occurrence of cometabolism of SAs and COD.

  11. Performance, carotenoids yield and microbial population dynamics in a photobioreactor system treating acidic wastewater: Effect of hydraulic retention time (HRT) and organic loading rate (OLR).

    Science.gov (United States)

    Liu, Shuli; Zhang, Guangming; Zhang, Jie; Li, Xiangkun; Li, Jianzheng

    2016-01-01

    Effects of hydraulic retention time (HRT) and influent organic loading rate (OLR) were investigated in a photobioreactor containing PNSB (Rhodopseudomonas palustris)-chemoheterotrophic bacteria to treat volatile fatty acid wastewater. Pollutants removal, biomass production and carotenoids yield in different phases were investigated in together with functional microbial population dynamics. The results indicated that properly decreasing HRT and increasing OLR improved the nutrient removal performance as well as the biomass and carotenoids productions. 85.7% COD, 89.9% TN and 91.8% TP removals were achieved under the optimal HRT of 48h and OLR of 2.51g/L/d. Meanwhile, the highest biomass production and carotenoids yield were 2719.3mg/L and 3.91mg/g-biomass respectively. In addition, HRT and OLR have obvious impacts on PNSB and total bacteria dynamics. Statistical analyses indicated that the COD removal exhibited a positive relationship with OLR, biomass and carotenoids production. PNSB/total bacteria ratio had a positive correlation with the carotenoids yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Mathematical modelling of digesta passage rate, mean retention time and in vivo apparent digestibility of two different lengths of hay and big-bale grass silage in ponies.

    Science.gov (United States)

    Moore-Colyer, M J S; Morrow, H J; Longland, A C

    2003-07-01

    Welsh-cross pony geldings (about 300 kg live weight) were used in a 4x4 Latin square experiment to determine the rate of passage and apparent digestibility of unchopped big-bale grass silage (BBL), chopped big-bale grass silage (BBS), unchopped grass hay (HL) and chopped grass hay (HS) offered at approximately 15 g/kg live weight per d. On day 1 of collection weeks, ponies were fed 85 g ytterbium chloride hexahydrate-marked feed 1.5 h after the morning meal. Total faecal collections commenced 8 h later and continued for 168 h. Apparent digestibilities of feed DM, organic matter (OM), crude protein (CP, Nx6.25), acid-detergent fibre (ADF) and neutral-detergent fibre (NDF) were also determined. Faecal excretion data were subjected to the models of Pond et al. (1988) and digesta mean retention time (MRT) calculated from these models and using the algebraic method of Thielmans et al. (1978). Silage had significantly (Peffect. All the models of Pond et al. (1988) accurately described (R(2)>0.8) the pattern of faecal marker excretion. MRT of BBL (29.0 h)>BBS(27 h)>HS and HL (26 h). Compartmental analysis using the G3 model of Pond et al. (1988) showed BBL and HS diets had longer MRT in the time-dependent compartment, whereas BBS and HL had longer MRT in the time-independent compartment. Results from this experiment indicate that BBL and BBS are readily accepted and digested by ponies. While Yb is a successful external marker for determining total tract MRT and for modelling faecal excretion curves in horses, the results did not allow any definite conclusions to be drawn on digesta MRT within the different compartments of the equid gut.

  13. Gatherings as a retention strategy.

    Science.gov (United States)

    Stokes, Lillian Gatlin

    2003-01-01

    Retention has long been an issue for minority students enrolled in nursing programs. Indiana University put into place an initiative to enhance retention. The initiative is "Gatherings" which provide a means for maintaining contact and direct communication with minority/international students. Gatherings allow students at varied levels in the program to interact with each other and to share issues and concerns. Over a five-year period, the benefits of this initiative have been voiced by students. These students have strongly encouraged continuation of "gatherings". Plans are underway to start similar sessions for all students.

  14. Performance of a haloalkaliphilic bioreactor and bacterial community shifts under different COD/SO{sub 4}{sup 2−} ratios and hydraulic retention times

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jie-Min [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Song, Zi-Yu [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); Yan, Dao-Jiang; Liu, Yi-Lan [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Mao-Hua [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); Cao, Hong-Bin [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); Xing, Jian-Min, E-mail: jmxing@home.ipe.ac.cn [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China)

    2014-06-01

    Highlights: • Haloalkaliphilic microorganisms were used to reduce sulfate. • Sulfide concentration reached up to 1603 mg/L. • There was no sulfide inhibition to haloalkaliphilic microorganisms. • Bacterial community of haloalkaliphilic bioreactor was studied. - Abstract: Sulfur dioxide from flue gas was converted into sulfate after the absorption of alkaline solutions. Haloalkaliphilic microorganisms have been used in reducing sulfate to decrease expenses and avoid sulfide inhibition. The effects of different COD/SO{sub 4}{sup 2−} ratios and hydraulic retention times (HRTs) on the sulfate removal efficiency and bacterial community were investigated in model experiments. Ethanol showed better performance as an electron donor than lactate. The optimum COD/SO{sub 4}{sup 2−} ratio and HRT were 4.0 and 18 h, respectively, with respective sulfate removal efficiency and rate of 97.8 ± 1.11% and 6.26 ± 0.0710 g/L d. Sulfide concentrations reached 1603 ± 3.38 mg/L. Based on denaturing gradient gel electrophoresis analysis of 16S rDNA, the major sulfate-reducing bacterium (SRB) was Desulfonatronovibrio sp., which was only detected at a COD/SO{sub 4}{sup 2−} ratio of 4.0 using ethanol as an electron donor. Different HRTs had no significant effect on the band corresponding to this species. PCR results show that methane-producing archaea (MPA) were from the acetoclastic methanogenic family Methanosarcinaceae. Quantitative real-time PCR did not demonstrate any significant competition between SRB and MPA. The findings of this study indicate that sulfate reduction, nitrate reduction, and sulfide oxidization may occur in the same bioreactor.

  15. Prediction of collision cross section and retention time for broad scope screening in gradient reversed-phase liquid chromatography-ion mobility-high resolution accurate mass spectrometry.

    Science.gov (United States)

    Mollerup, Christian Brinch; Mardal, Marie; Dalsgaard, Petur Weihe; Linnet, Kristian; Barron, Leon Patrick

    2018-03-23

    Exact mass, retention time (RT), and collision cross section (CCS) are used as identification parameters in liquid chromatography coupled to ion mobility high resolution accurate mass spectrometry (LC-IM-HRMS). Targeted screening analyses are now more flexible and can be expanded for suspect and non-targeted screening. These allow for tentative identification of new compounds, and in-silico predicted reference values are used for improving confidence and filtering false-positive identifications. In this work, predictions of both RT and CCS values are performed with machine learning using artificial neural networks (ANNs). Prediction was based on molecular descriptors, 827 RTs, and 357 CCS values from pharmaceuticals, drugs of abuse, and their metabolites. ANN models for the prediction of RT or CCS separately were examined, and the potential to predict both from a single model was investigated for the first time. The optimized combined RT-CCS model was a four-layered multi-layer perceptron ANN, and the 95th prediction error percentiles were within 2 min RT error and 5% relative CCS error for the external validation set (n = 36) and the full RT-CCS dataset (n = 357). 88.6% (n = 733) of predicted RTs were within 2 min error for the full dataset. Overall, when using 2 min RT error and 5% relative CCS error, 91.9% (n = 328) of compounds were retained, while 99.4% (n = 355) were retained when using at least one of these thresholds. This combined prediction approach can therefore be useful for rapid suspect/non-targeted screening involving HRMS, and will support current workflows. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Improved motor sequence retention by motionless listening.

    Science.gov (United States)

    Lahav, Amir; Katz, Tal; Chess, Roxanne; Saltzman, Elliot

    2013-05-01

    This study examined the effect of listening to a newly learned musical piece on subsequent motor retention of the piece. Thirty-six non-musicians were trained to play an unfamiliar melody on a piano keyboard. Next, they were randomly assigned to participate in three follow-up listening sessions over 1 week. Subjects who, during their listening sessions, listened to the same initial piece showed significant improvements in motor memory and retention of the piece despite the absence of physical practice. These improvements included increased pitch accuracy, time accuracy, and dynamic intensity of key pressing. Similar improvements, though to a lesser degree, were observed in subjects who, during their listening sessions, were distracted by another task. Control subjects, who after learning the piece had listened to nonmusical sounds, showed impaired motoric retention of the piece at 1 week from the initial acquisition day. These results imply that motor sequences can be established in motor memory without direct access to motor-related information. In addition, the study revealed that the listening-induced improvements did not generalize to the learning of a new musical piece composed of the same notes as the initial piece learned, limiting the effects to musical motor sequences that are already part of the individual's motor repertoire.

  17. Determining when a fracture occurred: Does the method matter? Analysis of the similarity of three different methods for estimating time since fracture of juvenile long bones.

    Science.gov (United States)

    Drury, Anne; Cunningham, Craig

    2018-01-01

    Radiographic fracture date estimation is a critical component of skeletal trauma analysis in the living. Several timetables have been proposed for how the appearance of radiographic features can be interpreted to provide a likely time frame for fracture occurrence. This study compares three such timetables for pediatric fractures, by Islam et al. (2000), Malone et al. (2011), and Prosser et al. (2012), in order to determine whether the fracture date ranges produced by using these methods are in agreement with one another. Fracture date ranges were estimated for 112 long bone fractures in 96 children aged 1-17 years, using the three different timetables. The extent of similarity of the intervals was tested by statistically comparing the overlap between the ranges. Results showed that none of the methods were in perfect agreement with one another. Differences seen included the size of the estimated date range for when a fracture occurred, and the specific dates given for both the upper and lower ends of the fracture date range. There was greater similarity between the ranges produced by Malone et al. (2011) and both the other two studies than there was between Islam et al. (2000) and Prosser et al. (2012). The greatest similarity existed between Malone et al. (2011) and Islam et al. (2000). The extent of differences between methods can vary widely, depending on the fracture analysed. Using one timetable gives an average earliest possible fracture date of less than 2 days before another, but the range was extreme, with one method estimating minimum time since fracture as 25 days before another method for a given fracture. In most cases, one method gave maximum time since fracture as a week less than the other two methods, but range was extreme and some estimates were nearly two months different. The variability in fracture date estimates given by these timetables indicates that caution should be exercised when estimating the timing of a juvenile fracture if relying

  18. A self-similar solution of a curved shock wave and its time-dependent force variation for a starting flat plate airfoil in supersonic flow

    Directory of Open Access Journals (Sweden)

    Zijun CHEN

    2018-02-01

    Full Text Available The problem of aeroelasticity and maneuvering of command surface and gust wing interaction involves a starting flow period which can be seen as the flow of an airfoil attaining suddenly an angle of attack. In the linear or nonlinear case, compressive Mach or shock waves are generated on the windward side and expansive Mach or rarefaction waves are generated on the leeward side. On each side, these waves are composed of an oblique steady state wave, a vertically-moving one-dimensional unsteady wave, and a secondary wave resulting from the interaction between the steady and unsteady ones. An analytical solution in the secondary wave has been obtained by Heaslet and Lomax in the linear case, and this linear solution has been borrowed to give an approximate solution by Bai and Wu for the nonlinear case. The structure of the secondary shock wave and the appearance of various force stages are two issues not yet considered in previous studies and has been studied in the present paper. A self-similar solution is obtained for the secondary shock wave, and the reason to have an initial force plateau as observed numerically is identified. Moreover, six theoretical characteristic time scales for pressure load variation are determined which explain the slope changes of the time-dependent force curve. Keywords: Force, Self-similar solution, Shock-shock interaction, Shock waves, Unsteady flow

  19. The influence of age at time of exposure to 226Ra or 239Pu on distribution, retention, postinjection survival, and tumor induction in beagle dogs

    International Nuclear Information System (INIS)

    Bruenger, F.W.; Lloyd, R.D.; Miller, S.C.

    1991-01-01

    The influence of age at injection of 226Ra or 239Pu on skeletal deposition and local distribution, the pattern of bone tumor formation, and postinjection survival was assessed in parallel short-term studies of mechanisms and lifetime toxicity. Beagles received a single intravenous injection of 226Ra or 239Pu at 3 months (juveniles), 17-19 months (young adults) or 60 months (mature). Data from short-term studies of mechanisms and dosimetry and from one dosage level of each of the toxicity experiments were compared. Skeletal growth and turnover produced differential initial deposition and distribution patterns typical for each age group. At 1 week after injection, skeletal retention of 226Ra or 239Pu was 68 and 68%, respectively, in the juveniles, 32 and 46% in the young adults, and 31 and 43% in the mature dogs. Comparing individual bones in the juveniles, gradients in the concentration of 239Pu were small since all bones were actively growing, but substantial gradients, corresponding to centers of ossification, were present within individual bones. In other age groups, local concentration gradients were less pronounced, but much larger differences were present among the various bones. In the toxicity study all animals injected with either 41 kBq 226Ra/kg or 11 kBq 239Pu/kg have died. The cumulative average skeletal doses to the presumed time of start of tumor growth (1 year before death) were 25 and 4 Gy, respectively, for the juveniles, 22 and 5 Gy for the young adults, and 15 and 4 Gy for the mature dogs. The highest bone tumor incidence was seen in the young adult groups. Differences were observed in location of bone tumors between dogs in the same age group given radium or plutonium and among age groups injected with either radionuclide, some of which could be explained by differences in local dose distributions

  20. Impact of sludge retention time on the fine composition of the microbial community and extracellular polymeric substances in a membrane bioreactor.

    Science.gov (United States)

    Silva, Ana F; Antunes, Sílvia; Saunders, Aaron; Freitas, Filomena; Vieira, Anabela; Galinha, Claudia F; Nielsen, Per H; Barreto Crespo, Maria Teresa; Carvalho, Gilda

    2016-10-01

    Membrane bioreactors (MBRs) are an advanced technology for wastewater treatment whose wide application has been hindered by rapid fouling of the membranes. MBRs can be operated with long sludge retention time (SRT), a crucial parameter impacting microbial selection in the reactor. This also affects filtration performance, since a major fouling agent are the extracellular polymeric substances (EPS). In this study, the impact of the SRT on the ecophysiology of the MBRs and, consequently, on membrane fouling was evaluated. A MBR was operated under a SRT of 60 days followed by a SRT of 20 days. A comprehensive analysis of the microbial community structure and EPS proteins and polysaccharide profiles of the mixed liquor and cake layer was carried out throughout both operation periods. The results of this study showed that the imposition of a shorter SRT led to a shift in the dominant bacterial populations. The mixed liquor and cake layer communities were very different, with Actinomycetales order standing out in the cake layer at SRT of 20 days. Overall, higher EPS concentrations (particularly proteins) were found at this SRT. Furthermore, EPS profiles were clearly affected by the SRT: it was possible to correlate a group of soluble EPS proteins with the SRT of 60 days, and a lower sludge age led to a lower diversity of polysaccharide sugar monomers, with an increase of glucose and galactose in the cake layer. This study improves our knowledge regarding the molecular reasons for fouling, which may contribute to improve MBR design and operation.

  1. Effect of mixture ratio, solids concentration and hydraulic retention time on the anaerobic digestion of the organic fraction of municipal solid waste.

    Science.gov (United States)

    Fongsatitkul, Prayoon; Elefsiniotis, Panagiotis; Wareham, David G

    2010-09-01

    This paper describes how the degradation of the organic fraction of municipal solid waste (OFMSW) is affected through codigestion with varying amounts of return activated sludge (RAS). Solid waste that had its inorganic fraction selectively removed was mixed with RAS in ratios of 100% OFMSW, 50% OFMSW/50% RAS, and 25% OFMSW/75% RAS. The total solids (TS) concentration was held at 8% and three anaerobic digester systems treating the mixtures were held (for the first run) at a total hydraulic retention time (HRT) of 28 days. Increasing amounts of RAS did not however improve the mixture's digestability, as indicated by little change and/or a drop in the main performance indices [including percentage volatile solids (VS) removal and specific gas production]. The optimum ratio in this research therefore appeared to be 100% OFMSW with an associated 85.1 ± 0.6% VS removal and 0.72 ± 0.01 L total gas g(- 1) VS. In the second run, the effect of increasing percentage of TS (8, 12% and 15%) at a system HRT of 28 days was observed to yield no improvement in the main performance indices (i.e. percentage VS removal and specific gas production). Finally, during the third run, variations in the total system HRT were investigated at an 8% TS, again using 100% OFMSW. Of the HRTs explored (23, 28 and 33 days), the longest HRT yielded the best performance overall, particularly in terms of specific gas production (0.77 ± 0.01 L total gas g(-1) VS).

  2. Hydraulic retention time and pH affect the performance and microbial communities of passive bioreactors for treatment of acid mine drainage.

    Science.gov (United States)

    Aoyagi, Tomo; Hamai, Takaya; Hori, Tomoyuki; Sato, Yuki; Kobayashi, Mikio; Sato, Yuya; Inaba, Tomohiro; Ogata, Atsushi; Habe, Hiroshi; Sakata, Takeshi

    2017-12-01

    For acceleration of removing toxic metals from acid mine drainage (AMD), the effects of hydraulic retention time (HRT) and pH on the reactor performance and microbial community structure in the depth direction of a laboratory-scale packed-bed bioreactor containing rice bran as waste organic material were investigated. The HRT was shortened stepwise from 25 to 12 h, 8 h, and 6 to 5 h under the neutral condition using AMD neutralized with limestone (pH 6.3), and from 25 to 20 h, 12 h, and 8 to 7 h under the acid condition using AMD (pH 3.0). Under the neutral condition, the bioreactor stably operated up to 6 h HRT, which was shorter than under the acid condition (up to 20 h HRT). During stable sulfate reduction, both the organic matter-remaining condition and the low oxidation-reduction potential condition in lower parts of the reactor were observed. Principal coordinate analysis of Illumina sequencing data of 16S rRNA genes revealed a dynamic transition of the microbial communities at the boundary between stable and unstable operation in response to reductions in HRT. During stable operation under both the neutral and acid conditions, several fermentative operational taxonomic units (OTUs) from the phyla Firmicutes and Bacteroidetes dominated in lower parts of the bioreactor, suggesting that co-existence of these OTUs might lead to metabolic activation of sulfate-reducing bacteria. In contrast, during unstable operation at shorter HRTs, an OTU from the candidate phylum OP11 were found under both conditions. This study demonstrated that these microorganisms can be used to monitor the treatment of AMD, which suggests stable or deteriorated performance of the system.

  3. Similar circuits but different connectivity patterns between the cerebellum, basal ganglia, and supplementary motor area in early Parkinson's disease patients and controls during predictive motor timing.

    Science.gov (United States)

    Husárová, Ivica; Mikl, Michal; Lungu, Ovidiu V; Mareček, Radek; Vaníček, Jiří; Bareš, Martin

    2013-10-01

    The cerebellum, basal ganglia (BG), and other cortical regions, such as supplementary motor area (SMA) have emerged as important structures dealing with various aspects of timing, yet the modulation of functional connectivity between them during motor timing tasks remains unexplored. We used dynamic causal modeling to investigate the differences in effective connectivity (EC) between these regions and its modulation by behavioral outcome during a motor timing prediction task in a group of 16 patients with early Parkinson's disease (PD) and 17 healthy controls. Behavioral events (hits and errors) constituted the driving input connected to the cerebellum, and the modulation in connectivity was assessed relative to the hit condition (successful interception of target). The driving input elicited response in the target area, while modulatory input changed the specific connection strength. The neuroimaging data revealed similar structure of intrinsic connectivity in both groups with unidirectional connections from cerebellum to both sides of the BG, from BG to the SMA, and then from SMA to the cerebellum. However, the type of intrinsic connection was different between two groups. In the PD group, the connection between the SMA and cerebellum was inhibitory in comparison to the HC group, where the connection was activated. Furthermore, the modulation of connectivity by the performance in the task was different between the two groups, with decreased connectivity between the cerebellum and left BG and SMA and a more pronounced symmetry of these connections in controls. In the same time, there was an increased EC between the cerebellum and both sides of BG with more pronounced asymmetry (stronger connection with left BG) in patients. In addition, in the PD group the modulatory input strengthened inhibitory connectivity between the SMA and the cerebellum, while in the HC group the excitatory connection was slightly strengthened. Our findings indicate that although early PD

  4. Measuring extended families over time in informal settlements in Nairobi, Kenya: Retention and data consistency in a two-round survey.

    Science.gov (United States)

    Madhavan, Sangeetha; Beguy, Donatien; Clark, Shelley; Kabiru, Caroline

    2018-01-01

    Researchers have increasingly turned to longitudinal data to understand how the family environment of children changes over time and how this change affects their well-being. While the value of such efforts is clear, the inherent challenges of collecting robust data over time may limit or bias our understanding of family complexity. Drawing on data from an exploratory study on kinship structure and support for low income single mothers and their young children in Nairobi, Kenya, this paper aims to (1) assess the strengths and weaknesses of our approach in reflecting the complexities of kinship dynamics and (2) analyze how methodological issues such as selection and reporting inconsistency can influence our understanding of the role of kin in children's lives. The analysis used data from two waves of the Kinship Support Tree (KST) project. The starting sample consisted of 462 single mothers with at least one child under the age of 7, with data collected on approximately 5,000 resident and nonresident kin. Descriptive statistics and conventional tests of significance were used to analyze selection factors and inconsistencies in reporting across waves. The study yielded a 91% retention rate after six months and the analysis provides some assurance that selectivity from attrition and reporting inconsistency are not entirely driven by shifts in support provision by kin. However, the selectivity of the sample underscores caution in generalizing the results. While the challenges of conducting follow-up surveys such as the KST are serious, these findings suggest that it is possible to collect consistent data on kinship structure and support from the perspective of children in a mobile population. Tracking kinship structure over time using the KST is not only feasible but more importantly is unlikely to lead to incomplete or biased understanding of kinship. After further testing with a wider range of women, we hope to disseminate our results for use in a wide range of

  5. Measuring extended families over time in informal settlements in Nairobi, Kenya: Retention and data consistency in a two-round survey

    Directory of Open Access Journals (Sweden)

    Sangeetha Madhavan

    2018-04-01

    Full Text Available Background: Researchers have increasingly turned to longitudinal data to understand how the family environment of children changes over time and how this change affects their well-being. While the value of such efforts is clear, the inherent challenges of collecting robust data over time may limit or bias our understanding of family complexity. Objective: Drawing on data from an exploratory study on kinship structure and support for low income single mothers and their young children in Nairobi, Kenya, this paper aims to (1 assess the strengths and weaknesses of our approach in reflecting the complexities of kinship dynamics and (2 analyze how methodological issues such as selection and reporting inconsistency can influence our understanding of the role of kin in children's lives. Methods: The analysis used data from two waves of the Kinship Support Tree (KST project. The starting sample consisted of 462 single mothers with at least one child under the age of 7, with data collected on approximately 5,000 resident and nonresident kin. Descriptive statistics and conventional tests of significance were used to analyze selection factors and inconsistencies in reporting across waves. Results: The study yielded a 91Š retention rate after six months and the analysis provides some assurance that selectivity from attrition and reporting inconsistency are not entirely driven by shifts in support provision by kin. However, the selectivity of the sample underscores caution in generalizing the results. Conclusions: While the challenges of conducting follow-up surveys such as the KST are serious, these findings suggest that it is possible to collect consistent data on kinship structure and support from the perspective of children in a mobile population. Tracking kinship structure over time using the KST is not only feasible but more importantly is unlikely to lead to incomplete or biased understanding of kinship. Contribution: After further testing with a

  6. Similarity Measure of Graphs

    Directory of Open Access Journals (Sweden)

    Amine Labriji

    2017-07-01

    Full Text Available The topic of identifying the similarity of graphs was considered as highly recommended research field in the Web semantic, artificial intelligence, the shape recognition and information research. One of the fundamental problems of graph databases is finding similar graphs to a graph query. Existing approaches dealing with this problem are usually based on the nodes and arcs of the two graphs, regardless of parental semantic links. For instance, a common connection is not identified as being part of the similarity of two graphs in cases like two graphs without common concepts, the measure of similarity based on the union of two graphs, or the one based on the notion of maximum common sub-graph (SCM, or the distance of edition of graphs. This leads to an inadequate situation in the context of information research. To overcome this problem, we suggest a new measure of similarity between graphs, based on the similarity measure of Wu and Palmer. We have shown that this new measure satisfies the properties of a measure of similarities and we applied this new measure on examples. The results show that our measure provides a run time with a gain of time compared to existing approaches. In addition, we compared the relevance of the similarity values obtained, it appears that this new graphs measure is advantageous and  offers a contribution to solving the problem mentioned above.

  7. Do Developmental Mathematics Programs Have a Causal Impact on Student Retention? An Application of Discrete-Time Survival and Regression-Discontinuity Analysis

    Science.gov (United States)

    Lesik, Sally A.

    2007-01-01

    The impact of academic programs--such as developmental mathematics programs--on student retention, has been a controversial topic for administrators, policy makers, and faculty in higher education. Despite deep interest in the effectiveness of these programs in retaining students, scholars have been unable to determine whether such programs have a…

  8. Twelve Weeks of Sprint Interval Training Improves Indices of Cardiometabolic Health Similar to Traditional Endurance Training despite a Five-Fold Lower Exercise Volume and Time Commitment.

    Directory of Open Access Journals (Sweden)

    Jenna B Gillen

    Full Text Available We investigated whether sprint interval training (SIT was a time-efficient exercise strategy to improve insulin sensitivity and other indices of cardiometabolic health to the same extent as traditional moderate-intensity continuous training (MICT. SIT involved 1 minute of intense exercise within a 10-minute time commitment, whereas MICT involved 50 minutes of continuous exercise per session.Sedentary men (27±8y; BMI = 26±6kg/m2 performed three weekly sessions of SIT (n = 9 or MICT (n = 10 for 12 weeks or served as non-training controls (n = 6. SIT involved 3x20-second 'all-out' cycle sprints (~500W interspersed with 2 minutes of cycling at 50W, whereas MICT involved 45 minutes of continuous cycling at ~70% maximal heart rate (~110W. Both protocols involved a 2-minute warm-up and 3-minute cool-down at 50W.Peak oxygen uptake increased after training by 19% in both groups (SIT: 32±7 to 38±8; MICT: 34±6 to 40±8ml/kg/min; p<0.001 for both. Insulin sensitivity index (CSI, determined by intravenous glucose tolerance tests performed before and 72 hours after training, increased similarly after SIT (4.9±2.5 to 7.5±4.7, p = 0.002 and MICT (5.0±3.3 to 6.7±5.0 x 10-4 min-1 [μU/mL]-1, p = 0.013 (p<0.05. Skeletal muscle mitochondrial content also increased similarly after SIT and MICT, as primarily reflected by the maximal activity of citrate synthase (CS; P<0.001. The corresponding changes in the control group were small for VO2peak (p = 0.99, CSI (p = 0.63 and CS (p = 0.97.Twelve weeks of brief intense interval exercise improved indices of cardiometabolic health to the same extent as traditional endurance training in sedentary men, despite a five-fold lower exercise volume and time commitment.

  9. Correlation between HBsAg, prothrombin time activity, and indocyanine green retention rate at 15 minutes in patients with HBeAg-positive chronic HBV infection

    Directory of Open Access Journals (Sweden)

    FAN Wenhai

    2016-11-01

    Full Text Available ObjectiveTo investigate the correlation between HBsAg, prothrombin time activity (PTA, and indocyanine green retention rate at 15 minutes (ICG R15 in patients with HBeAg-positive chronic HBV infection. MethodsA total of 92 patients with HBeAg-positive chronic HBV infection who were admitted to The First Hospital of Lanzhou University from December 2015 to April 2016 were enrolled and divided into chronic hepatitis B (CHB group (24 patients, compensated liver cirrhosis group (38 patients, and decompensated liver cirrhosis group (30 patients. Serum HBsAg quantitation, PTA test, and liver reserve function test (ICG R15 were performed for all patients. The chi-square test was used for comparison of categorical data between groups, an analysis of variance was used for comparison of continuous data between multiple groups, and a Pearson correlation analysis was also performed. ResultsThere were significant differences between the three groups in serum HBsAg quantitation (3.82±0.43 log10IU/ml vs 2.88±0.36 log10IU/ml vs 2.60±0.27 log10IU/ml, F=25.19, P<0.001, ICG R15 (7.51%±3.10% vs 9.57%±8.18% vs 24.13%±14.28%, F=24.00, P=0.001, and PTA (8100%±1762% vs 83.08%±9.64% vs 62.32%±16.90%, F=13.42, P=0.009. The correlation analysis showed that PTA was negatively correlated with ICG R15 in all three groups (r=-0.948, -0.602, and -0.735, all P<0.01. In the compensated liver cirrhosis group and decompensated liver cirrhosis group, HBsAg was positively correlated with PTA (r=0.410 and 0.473, both P<0.05 and negatively correlated with ICG R15 (r=-0.427 and -0.768, P<0.01. ConclusionIn HBeAg positive patients, there are certain correlations between HBsAg, PTA, and ICG R15, which, to a certain degree, reflects the liver reserve function in patients with chronic HBV infection.

  10. A comparison of the effect of forage type and level of feeding on the digestibility and gastrointestinal mean retention time of dry forages given to cattle, sheep, ponies and donkeys.

    Science.gov (United States)

    Pearson, R A; Archibald, R F; Muirhead, R H

    2006-01-01

    Four cattle, sheep, ponies and donkeys were fed dehydrated lucerne, early-cut hay, later-cut hay or barley straw in a Latin square-based design for four periods of 35 d. In the first sub-period animals were fed the diets ad libitum (1-21 d) and in the second sub-period they were fed the same diet restricted to 0.75 of ad libitum intake (days 22-35). Measurements of forage intake, apparent digestibilities and gastrointestinal mean retention times (MRT) were made in the last 7 d of each sub-period. Differences between species in voluntary DM intake (VDMI; g/kg live weight (LW)(0.75) and g/LW) were greatest on the lucerne and least on barley straw. Cattle VDMI (g/kg LW(0.75)) compared with intake of the other species was > ponies > sheep > donkeys on lucerne. On barley straw VDMI (g/kg LW(0.75)) of cattle compared with intake of the other species was = donkey = ponies > sheep. VDMI of hays were intermediate between the lucerne and straw forages. Apparent digestibilities of DM, organic matter (OM), neutral-detergent fibre (NDF) and acid-detergent fibre (ADF) of the lucerne and hays were higher in the ruminants than in the equids. Effect of feeding level was not significant. Gastrointestinal MRT was shorter in the equids than in the ruminants. On straw diets donkeys showed similar apparent digestibilities of feed components to those of the cattle, whilst apparent digestibility of the straw diet by the ponies was lowest. Results are discussed in relation to evolutionary differences in feeding and digestion strategy associated with fore- or hind-gut fermentation in ruminants and equids.

  11. Quick-low-density parity check and dynamic threshold voltage optimization in 1X nm triple-level cell NAND flash memory with comprehensive analysis of endurance, retention-time, and temperature variation

    Science.gov (United States)

    Doi, Masafumi; Tokutomi, Tsukasa; Hachiya, Shogo; Kobayashi, Atsuro; Tanakamaru, Shuhei; Ning, Sheyang; Ogura Iwasaki, Tomoko; Takeuchi, Ken

    2016-08-01

    NAND flash memory’s reliability degrades with increasing endurance, retention-time and/or temperature. After a comprehensive evaluation of 1X nm triple-level cell (TLC) NAND flash, two highly reliable techniques are proposed. The first proposal, quick low-density parity check (Quick-LDPC), requires only one cell read in order to accurately estimate a bit-error rate (BER) that includes the effects of temperature, write and erase (W/E) cycles and retention-time. As a result, 83% read latency reduction is achieved compared to conventional AEP-LDPC. Also, W/E cycling is extended by 100% compared with conventional Bose-Chaudhuri-Hocquenghem (BCH) error-correcting code (ECC). The second proposal, dynamic threshold voltage optimization (DVO) has two parts, adaptive V Ref shift (AVS) and V TH space control (VSC). AVS reduces read error and latency by adaptively optimizing the reference voltage (V Ref) based on temperature, W/E cycles and retention-time. AVS stores the optimal V Ref’s in a table in order to enable one cell read. VSC further improves AVS by optimizing the voltage margins between V TH states. DVO reduces BER by 80%.

  12. Recycling retention functions

    International Nuclear Information System (INIS)

    Skrable, K.W.; Chabot, G.E.; Johnson, M.H.

    1981-01-01

    Beginning with the concept of any number of physiologically meaningful compartments that recycle material with a central extracellular fluid compartment and considering various excretion pathways, we solve the differential equations describing the kinetics by the method of Laplace to obtain concise algebraic expressions for the retentions. These expressions contain both fundamental and eigenvalue rate constants; the eigenvalue rate constants are obtained from the solution of a polynomial incorporating the fundamental rate constants. Mathematically exact expressions that predict the biodistribution resulting from continuous uptakes are used to obtain very simple mathematically exact steady state expressions as well as approximate expressions applicable to any time. These steady state and approximate expressions contain only the fundamental rate constants; also, they include a recycling factor that describes the increase in the biodistributions because of recycling. To obtain the values of the fundamental rate constants, short term kinetics studies along with data on the long term distributions are suggested. Retention functions obtained in this way predict both the short term and long term distributions; they therefore are useful in the interpretation of bioassay data and in the estimation of internal doses

  13. Cycling Time Trial Performance 4 Hours After Glycogen-Lowering Exercise Is Similarly Enhanced by Recovery Nondairy Chocolate Beverages Versus Chocolate Milk.

    Science.gov (United States)

    Upshaw, Adam U; Wong, Tiffany S; Bandegan, Arash; Lemon, Peter W

    2016-02-01

    Postexercise chocolate milk ingestion has been shown to enhance both glycogen resynthesis and subsequent exercise performance. To assess whether nondairy chocolate beverage ingestion post-glycogen-lowering exercise can enhance 20-km cycling time trial performance 4 hr later, eight healthy trained male cyclists (21.8 ± 2.3y, VO2max = 61.2 ± 1.4 ml·kg-1·min-1; M ± SD) completed a series of intense cycling intervals designed to lower muscle glycogen (Jentjens & Jeukendrup, 2003) followed by 4 hr of recovery and a subsequent 20-km cycling time trial. During the first 2 hr of recovery, participants ingested chocolate dairy milk (DAIRYCHOC), chocolate soy beverage (SOYCHOC), chocolate hemp beverage (HEMPCHOC), low-fat dairy milk (MILK), or a low-energy artificially sweetened, flavored beverage (PLACEBO) at 30-min intervals in a double-blind, counterbalanced repeated-measures design. All drinks, except the PLACEBO (247 kJ) were isoenergetic (2,107 kJ), and all chocolate-flavored drinks provided 1-g CHO·kg body mass-1·h-1. Fluid intake across treatments was equalized (2,262 ± 148 ml) by ingesting appropriate quantities of water based on drink intake. The CHO:PRO ratio was 4:1, 1.5:1, 4:1, and 6:1 for DAIRYCHOC, MILK, SOYCHOC, and HEMPCHOC, respectively. One-way analysis of variance with repeated measures showed time trial performance (DAIRYCHOC = 34.58 ± 2.5 min, SOYCHOC = 34.83 ± 2.2 min, HEMPCHOC = 34.88 ± 1.1 min, MILK = 34.47 ± 1.7 min) was enhanced similarly vs PLACEBO (37.85 ± 2.1) for all treatments (p = .019) These data suggest that postexercise macronutrient and total energy intake are more important for same-day 20-km cycling time trial performance after glycogen-lowering exercise than protein type or protein-to-carbohydrate ratio.

  14. Gas Retention in a Heated Plastic Bonded Explosive (LX-14).

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, Michael L. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Engineering Sciences Center; Kaneshige, Michael J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Energetics Components Center; Erikson, William W. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Engineering Sciences Center; Meirs, Kevin T. [U.S. Army Armament Research, Development and Engineering Center (ARDEC), Picatinny Arsenal, NJ (United States)

    2017-09-01

    In prior work, we found that the nitroplasticizer in the plastic bonded explosive PBX 9501 played a crucial role in cookoff, especially when predicting response in larger systems [1]. We have recently completed experiments with a similar explosive, LX-14, that has a relatively nonreactive binder. We expected the ignition times for LX-14 to be longer than PBX 9501 since PBX 9501 has a more reactive binder. However, our experiments show the opposite trend. This paradox can be explained by retention of reactive gases within the interior of LX-14 by the higher strength binder resulting in faster ignition times. In contrast, the binder in PBX 9501 melts at low temperatures and does not retain decomposition gases as well as the LX-14 binder. Retention of reactive gases in LX-14 may also explain the more violent response in oblique impact tests [2] when compared to PBX 9501.

  15. 28 CFR 345.67 - Retention of benefits.

    Science.gov (United States)

    2010-07-01

    ... INDUSTRIES (FPI) INMATE WORK PROGRAMS Inmate Pay and Benefits § 345.67 Retention of benefits. (a) Job retention. Ordinarily, when an inmate is absent from the job for a significant period of time, the SOI will... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Retention of benefits. 345.67 Section 345...

  16. Importance of material matching in the calibration of asymmetric flow field-flow fractionation: material specificity and nanoparticle surface coating effects on retention time

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Haiou [U.S. Food and Drug Administration, Office of Regulatory Affairs, Arkansas Regional Laboratory (United States); Quevedo, Ivan R. [Universidad Iberoamericana, Departamento de Ingeniería y Ciencias Químicas (Mexico); Linder, Sean W.; Fong, Andrew; Mudalige, Thilak K., E-mail: Thilak.Mudalige@fda.hhs.gov [U.S. Food and Drug Administration, Office of Regulatory Affairs, Arkansas Regional Laboratory (United States)

    2016-10-15

    Asymmetric flow field-flow fractionation (AF4) coupled with dynamic light scattering or multiangle light scattering detectors is a promising technique for the size-based separation of colloidal particles (nano- and submicron scale) and the online determination of the particle size of the separated fractions in aqueous suspensions. In most cases, the applications of these detectors are problematic due to the material-specific properties of the analyte that results in erroneous calculations, and as an alternative, different nanoparticle size standards are required to properly calibrate the size-based retention in AF4. The availability of nanoparticle size standards in different materials is limited, and this deviation from ideal conditions of retention is mainly due to material-specific and particle coating-specific membrane–particle interactions. Here, we present an experimental method on the applicability of polystyrene nanoparticles (PS NP) as standard for AF4 calibration and compare with gold nanoparticle (Au NP) standards having different nominal sizes and surface functionalities.

  17. Importance of material matching in the calibration of asymmetric flow field-flow fractionation: material specificity and nanoparticle surface coating effects on retention time

    International Nuclear Information System (INIS)

    Qu, Haiou; Quevedo, Ivan R.; Linder, Sean W.; Fong, Andrew; Mudalige, Thilak K.

    2016-01-01

    Asymmetric flow field-flow fractionation (AF4) coupled with dynamic light scattering or multiangle light scattering detectors is a promising technique for the size-based separation of colloidal particles (nano- and submicron scale) and the online determination of the particle size of the separated fractions in aqueous suspensions. In most cases, the applications of these detectors are problematic due to the material-specific properties of the analyte that results in erroneous calculations, and as an alternative, different nanoparticle size standards are required to properly calibrate the size-based retention in AF4. The availability of nanoparticle size standards in different materials is limited, and this deviation from ideal conditions of retention is mainly due to material-specific and particle coating-specific membrane–particle interactions. Here, we present an experimental method on the applicability of polystyrene nanoparticles (PS NP) as standard for AF4 calibration and compare with gold nanoparticle (Au NP) standards having different nominal sizes and surface functionalities.

  18. Urinary retention in women

    African Journals Online (AJOL)

    Urinary retention in women. Urinary retention in women is often transient and of no known cause. ... stones, constipation, urethral cancer, uterine fibroids ... present with abnormal bladder function secondary to ... (CT), magnetic resonance imaging (MRI) or myelography ... full blood count, urea, electrolytes and creatinine can ...

  19. Strategies for improving employee retention.

    Science.gov (United States)

    Verlander, Edward G; Evans, Martin R

    2007-03-28

    This article proposes a solution to the perennial problem of talent retention in the clinical laboratory. It includes the presentation of 12 strategies that may be used to significantly improve institutional identity formation and establishment of the psychological contract that employees form with laboratory management. Identity formation and psychological contracting are deemed as essential in helping reduce employee turnover and increase retention. The 12 conversational strategies may be used as a set of best practices for all employees, but most importantly for new employees, and should be implemented at the critical moment when employees first join the laboratory. This time is referred to as "retention on-boarding"--the period of induction and laboratory orientation. Retention on-boarding involves a dialogue between employees and management that is focused on the psychological, practical, cultural, and political dimensions of the laboratory. It is placed in the context of the modern clinical laboratory, which is faced with employing and managing Generation X knowledge workers. Specific topics and broad content areas of those conversations are outlined.

  20. Post 2000-swarm microearthquake activity in the principal focal zone of West Bohemia/Vogtland: space-time distribution and waveform similarity analysis

    Czech Academy of Sciences Publication Activity Database

    Fischer, Tomáš; Michálek, J.

    2008-01-01

    Roč. 52, č. 4 (2008), s. 493-511 ISSN 0039-3169 R&D Projects: GA ČR(CZ) GA205/06/1780 Grant - others:GA UK(CZ) 105707 Institutional research plan: CEZ:AV0Z30120515 Keywords : earthquake swarms * relative location * waveform similarity * seismic activity * West Bohemia/Vogtland Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.770, year: 2008

  1. Motor skill learning, retention, and control deficits in Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Lisa Katharina Pendt

    Full Text Available Parkinson's disease, which affects the basal ganglia, is known to lead to various impairments of motor control. Since the basal ganglia have also been shown to be involved in learning processes, motor learning has frequently been investigated in this group of patients. However, results are still inconsistent, mainly due to skill levels and time scales of testing. To bridge across the time scale problem, the present study examined de novo skill learning over a long series of practice sessions that comprised early and late learning stages as well as retention. 19 non-demented, medicated, mild to moderate patients with Parkinson's disease and 19 healthy age and gender matched participants practiced a novel throwing task over five days in a virtual environment where timing of release was a critical element. Six patients and seven control participants came to an additional long-term retention testing after seven to nine months. Changes in task performance were analyzed by a method that differentiates between three components of motor learning prominent in different stages of learning: Tolerance, Noise and Covariation. In addition, kinematic analysis related the influence of skill levels as affected by the specific motor control deficits in Parkinson patients to the process of learning. As a result, patients showed similar learning in early and late stages compared to the control subjects. Differences occurred in short-term retention tests; patients' performance constantly decreased after breaks arising from poorer release timing. However, patients were able to overcome the initial timing problems within the course of each practice session and could further improve their throwing performance. Thus, results demonstrate the intact ability to learn a novel motor skill in non-demented, medicated patients with Parkinson's disease and indicate confounding effects of motor control deficits on retention performance.

  2. Effects of pH and hydraulic retention time on hydrogen production versus methanogenesis during anaerobic fermentation of organic household solid waste under extreme-thermophilic temperature (70ºC)

    DEFF Research Database (Denmark)

    Liu, Dawei; Zeng, Raymond Jianxiong; Angelidaki, Irini

    2008-01-01

    Two continuously stirred tank reactors were operated with household solid waste at 70°C, for hydrogen and methane production. The individual effect of hydraulic retention time (HRT as 1, 2, 3, 4, and 6 days) at pH 7 or pH (5, 5.5, 6, 6.5, 7) at 3-day HRT was investigated on the hydrogen production...... versus methanogenesis. It was found that at pH 7, the maximum hydrogen yield was 107 mL-H2/g VSadded (volatile solid added) but no stable hydrogen production was obtained as after some time methanogenesis was initiated at all tested HRTs. This demonstrated that sludge retention time alone was not enough...... for washing out the methanogens at pH 7 under extreme-thermophilic conditions. Oppositely, we showed that keeping the pH level at 5.5 was enough to inhibit methane and produce hydrogen stably at 3-day HRT. However, the maximum stable hydrogen yield was low at 21 mL-H2/g VSadded. Biotechnol. Bioeng. 2008...

  3. Comparisons of methods for calculating retention and separation of chromatographic peaks

    International Nuclear Information System (INIS)

    Pauls, R.E.; Rogers, L.B.

    1976-09-01

    The accuracy and precision of calculating retention times from means and peak maxima have been examined using an exponentially modified Gaussian as a model for tailed chromotographic peaks. At different levels of random noise, retention times could be determined with nearly the same precision using either the mean or maximum. However, the accuracies and precisions of the maxima were affected by the number of points used in the digital smooth and by the number of points recorded per unit of standard deviation. For two peaks of similar shape, consistency in the selection of points should usually permit differences in retention to be determined accurately and with approximately the same precision using maxima, means, or half-heights on the leading side of the peak

  4. Supporting nurse practitioner education: Preceptorship recruitment and retention

    Directory of Open Access Journals (Sweden)

    Eric Staples

    2018-04-01

    Full Text Available Objectives: Clinical experience is an essential component of nurse practitioner (NP education that relies heavily on preceptors. Recruitment and retention of preceptors is challenging due to many variables that can affect NP education and practice. We surveyed Canadian NP programs to understand their preceptorship structures, how they support preceptorship, and to identify gaps and challenges to recruitment and retention of preceptors. Methods: An 18-item survey, developed by the NP Education Interest Group, was distributed to 24 universities across 10 Canadian provinces. Construct validity and reliability was assessed by experienced NPs and NP faculty. Data were analyzed using relative frequency statistics and thematic analysis. Participants consisted of administrative staff and/or faculty designated as responsible for recruitment and retention of NP preceptors. Results: Seventeen returned surveys were analyzed and demonstrated more similarities than differences across Canada's NP programs, particularly related to barriers affecting recruitment and retention of preceptors. The findings identified NP programs have too many students for the number of available clinical sites/preceptors, resulting in overutilization, burnout, or refusal to take students. Competition with other health disciplines for clinical placements was identified as a challenge to placements. Respondents commented they lack time to recruit, provide follow-up, offer support, or seek preceptors' feedback due to competing work demands. They identified the need for standardized funding for preceptor remuneration and recognition across the country. Conclusion: The findings suggest the need for exploring a wider intraprofessional collaboration among graduate NP programs/faculty, clinical placement sites, and NPs to facilitate the recruitment and retention of preceptors.

  5. Biomarker- and similarity coefficient-based approaches to bacterial mixture characterization using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).

    Science.gov (United States)

    Zhang, Lin; Smart, Sonja; Sandrin, Todd R

    2015-11-05

    MALDI-TOF MS profiling has been shown to be a rapid and reliable method to characterize pure cultures of bacteria. Currently, there is keen interest in using this technique to identify bacteria in mixtures. Promising results have been reported with two- or three-isolate model systems using biomarker-based approaches. In this work, we applied MALDI-TOF MS-based methods to a more complex model mixture containing six bacteria. We employed: 1) a biomarker-based approach that has previously been shown to be useful in identification of individual bacteria in pure cultures and simple mixtures and 2) a similarity coefficient-based approach that is routinely and nearly exclusively applied to identification of individual bacteria in pure cultures. Both strategies were developed and evaluated using blind-coded mixtures. With regard to the biomarker-based approach, results showed that most peaks in mixture spectra could be assigned to those found in spectra of each component bacterium; however, peaks shared by two isolates as well as peaks that could not be assigned to any individual component isolate were observed. For two-isolate blind-coded samples, bacteria were correctly identified using both similarity coefficient- and biomarker-based strategies, while for blind-coded samples containing more than two isolates, bacteria were more effectively identified using a biomarker-based strategy.

  6. Liquid Effluent Retention Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Liquid Effluent Retention Facility (LERF) is located in the central part of the Hanford Site. LERF is permitted by the State of Washington and has three liquid...

  7. Krypton retention on solid adsorbents

    International Nuclear Information System (INIS)

    Monson, P.R. Jr.

    1982-01-01

    An experimental laboratory program was conducted to develop economical solid adsorbents for the retention of krypton from a dissolver off-gas stream. The study indicates that a solid adsorbent system is feasible and competitive with other developing systems which utilize fluorocarbon absorption nd cryogenic distillation. This technology may have potential applications not only in nuclear fuel reprocessing plants, but also in nuclear reactors and in environmental monitoring. Of the 13 prospective adsorbents evaluated with respect to adsorption capacity and cost, the commercially available hydrogen mordenite was the most cost-effective material at subambient temperatures (-40 0 to -80 0 C). Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite

  8. Distribution and retention of 239Pu administered to rats at representative stages of gestation

    International Nuclear Information System (INIS)

    Sikov, M.R.; Andrew, F.D.

    1979-01-01

    The distribution of 239 Pu in tissues of mothers and their offspring, as well as in other fetoplacental unit components, was measured following intravenous injection at 9, 15, or 19 days of gestation. Deposition levels and retention were markedly different at the earliest time of gestation, but less difference was seen between the two later times. Radiation dose to the fetus was similar for all ages, but dose to specific organs and tissues varied with stage of gestation

  9. Blastocystis Isolates from Patients with Irritable Bowel Syndrome and from Asymptomatic Carriers Exhibit Similar Parasitological Loads, but Significantly Different Generation Times and Genetic Variability across Multiple Subtypes.

    Directory of Open Access Journals (Sweden)

    Gie-Bele Vargas-Sanchez

    Full Text Available Blastocystis spp is a common intestinal parasite of humans and animals that has been associated to the etiology of irritable bowel syndrome (IBS; however, some studies have not found this association. Furthermore, many biological features of Blastocystis are little known. The objective of present study was to assess the generation times of Blastocystis cultures, from IBS patients and from asymptomatic carriers. A total of 100 isolates were obtained from 50 IBS patients and from 50 asymptomatic carriers. Up to 50 mg of feces from each participant were cultured in Barret's and in Pavlova's media during 48 h. Initial and final parasitological load were measured by microscopy and by quantitative PCR. Amplicons were purified, sequenced and submitted to GenBank; sequences were analysed for genetic diversity and a Bayesian inference allowed identifying genetic subtypes (ST. Generation times for Blastocystis isolates in both media, based on microscopic measures and molecular assays, were calculated. The clinical symptoms of IBS patients and distribution of Blastocystis ST 1, 2 and 3 in both groups was comparable to previous reports. Interestingly, the group of cases showed scarce mean nucleotide diversity (π as compared to the control group (0.011±0.016 and 0.118±0.177, respectively, whilst high gene flow and small genetic differentiation indexes between different ST were found. Besides, Tajima's D test showed negative values for ST1-ST3. No statistical differences regarding parasitological load between cases and controls in both media, as searched by microscopy and by qPCR, were detected except that parasites grew faster in Barret's than in Pavlova's medium. Interestingly, slow growth of isolates recovered from cases in comparison to those of controls was observed (p<0.05. We propose that generation times of Blastocystis might be easily affected by intestinal environmental changes due to IBS probably because virulent strains with slow growth may be

  10. The influence of flushing time on the bonding quality of liquid white cast iron on the solid surface of similar material

    Science.gov (United States)

    Bandanadjaja, Beny; Purwadi, Wiwik; Idamayanti, Dewi; Lilansa, Noval; Hanaldi, Kus; Nurzaenal, Friya Kurnia

    2018-05-01

    Hard metal castings are widely used in the coal mill pulverizer as construction material for coal crushers. During its operation crushers and mills experience degradation caused by abrasion load. This research dealed with the surface overlaying of similiar material on the surface of white cast iron by mean of gravity casting. The die blank casting was preheated prior to the casting process of outer layer made of Ni-Hard white cast iron to guarantee bonding processes and avoid any crack. The preheating temperature of die blankin ther range of 500C up to 850C was set up to reach the interface temperature in the range of 887°C -1198°C and the flushing time was varied between 10-20 seconds. Studies carried on the microstructure of sample material revealed a formation of metallurgical bonding at the preheating temperature above 625 °C by pouring temperature ranging from 1438 °C to 1468 °C. Metallographical and chemical composition by mean of EDS examination were performed to observed the resut. This research concludes that the casting of Ni-Hard 1 overlay by applying gravity casting method can be done by preheating the surface of casting to 625 °C, interface temperature of 1150 °C, flushing time of 7 seconds and pouring temperature of 1430 °C. Excellent metallurgical bonding at the contact area between dieblank and overlay material has been achieved in which there is no parting line at the interface area to be observed.

  11. Urinary Analysis of Fluid Retention in the General Population: A Cross-Sectional Study.

    Directory of Open Access Journals (Sweden)

    Robert G Hahn

    Full Text Available Renal conservation (retention of fluid might affect the outcome of hospital care and can be indicated by increased urinary concentrations of metabolic waste products. We obtained a reference material for further studies by exploring the prevalence of fluid retention in a healthy population.Spot urine sampling was performed in 300 healthy hospital workers. A previously validated algorithm summarized the urine-specific gravity, osmolality, creatinine, and color to a fluid retention index (FRI, where 4.0 is the cut-off for fluid retention consistent with dehydration. In 50 of the volunteers, we also studied the relationships between FRI, plasma osmolality, and water-retaining hormones.The cut-off for fluid retention (FRI ≥ 4.0 was reached by 38% of the population. No correlation was found between the FRI and the time of the day of urine sample collection, and the FRI was only marginally correlated with the time period spent without fluid intake. Volunteers with fluid retention were younger, generally men, and more often had albuminuria (88% vs. 34%, P < 0.001. Plasma osmolality and plasma sodium were somewhat higher in those with a high FRI (mean 294.8 vs. 293.4 mosmol/kg and 140.3 vs. 139.9 mmol/l. Plasma vasopressin was consistently below the limit of detection, and the plasma cortisol, aldosterone, and renin concentrations were similar in subjects with a high or low FRI. The very highest FRI values (≥ 5.0, N = 61 were always accompanied by albuminuria.Fluid retention consistent with moderate dehydration is common in healthy staff working in a Swedish hospital.

  12. A dynamic processes study of PM retention by trees under different wind conditions.

    Science.gov (United States)

    Xie, Changkun; Kan, Liyan; Guo, Jiankang; Jin, Sijia; Li, Zhigang; Chen, Dan; Li, Xin; Che, Shengquan

    2018-02-01

    Particulate matter (PM) is one of the most serious environmental problems, exacerbating respiratory and vascular illnesses. Plants have the ability to reduce non-point source PM pollution through retention on leaves and branches. Studies of the dynamic processes of PM retention by plants and the mechanisms influencing this process will help to improve the efficiency of urban greening for PM reduction. We examined dynamic processes of PM retention and the major factors influencing PM retention by six trees with different branch structure characteristics in wind tunnel experiments at three different wind speeds. The results showed that the changes of PM numbers retained by plant leaves over time were complex dynamic processes for which maximum values could exceed minimum values by over 10 times. The average value of PM measured in multiple periods and situations can be considered a reliable indicator of the ability of the plant to retain PM. The dynamic processes were similar for PM 10 and PM 2.5 . They could be clustered into three groups simulated by continually-rising, inverse U-shaped, and U-shaped polynomial functions, respectively. The processes were the synthetic effect of characteristics such as species, wind speed, period of exposure and their interactions. Continually-rising functions always explained PM retention in species with extremely complex branch structure. Inverse U-shaped processes explained PM retention in species with relatively simple branch structure and gentle wind. The U-shaped processes mainly explained PM retention at high wind speeds and in species with a relatively simple crown. These results indicate that using plants with complex crowns in urban greening and decreasing wind speed in plant communities increases the chance of continually-rising or inverse U-shaped relationships, which have a positive effect in reducing PM pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Anaerobic digestion of the vinasses from the fermentation of Agave tequilana Weber to tequila: The effect of pH, temperature and hydraulic retention time on the production of hydrogen and methane

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza-Escalante, Froylan M.; Pelayo-Ortiz, Carlos; Navarro-Corona, Jose; Gonzalez-Garcia, Yolanda [Department of Chemical Engineering, University of Guadalajara, Blvd. M. Garcia Barragan No. 1421, Guadalajara CP 44430 (Mexico); Bories, Andre [INRA-Unite Experimentale de Pech-Rouge, 11430 Gruissan (France); Gutierrez-Pulido, Humberto [Department of Mathematics, University of Guadalajara, Blvd. M. Garcia Barragan No. 1421, Guadalajara CP 44430 (Mexico)

    2009-01-15

    The objective of this work was to study the effect of three operational parameters (pH, hydraulic retention time (HRT) and growing temperature) on a semi-continuous bioreactor treating Tequila's vinasses by anaerobic digestion (AD). The response was measured through four response variables: total reducing sugars (TRS) consumption, VFA's, hydrogen and methane production. Trials were done according to a factorial design. The experimental results were studied through a multiple response optimization (MRO) analysis to find single and multiple optimums for the above-mentioned variables. Mathematical models that can describe the effect of the operational parameters on each response variable were found. In this study it is shown that hydrogen production is favored at thermophilic growth (55 C), operating the reactor at a slight acidic pH range and at the higher HRT in the boundaries of the experimental region. (author)

  14. Anaerobic digestion of the vinasses from the fermentation of Agave tequilana Weber to tequila: The effect of pH, temperature and hydraulic retention time on the production of hydrogen and methane

    International Nuclear Information System (INIS)

    Espinoza-Escalante, Froylan M.; Pelayo-Ortiz, Carlos; Navarro-Corona, Jose; Gonzalez-Garcia, Yolanda; Bories, Andre; Gutierrez-Pulido, Humberto

    2009-01-01

    The objective of this work was to study the effect of three operational parameters (pH, hydraulic retention time (HRT) and growing temperature) on a semi-continuous bioreactor treating Tequila's vinasses by anaerobic digestion (AD). The response was measured through four response variables: total reducing sugars (TRS) consumption, VFA's, hydrogen and methane production. Trials were done according to a factorial design. The experimental results were studied through a multiple response optimization (MRO) analysis to find single and multiple optimums for the above-mentioned variables. Mathematical models that can describe the effect of the operational parameters on each response variable were found. In this study it is shown that hydrogen production is favored at thermophilic growth (55 deg. C), operating the reactor at a slight acidic pH range and at the higher HRT in the boundaries of the experimental region

  15. Factors influencing recruitment and retention of professional nurses ...

    African Journals Online (AJOL)

    J. Lyn Haskins

    factors influencing recruitment and retention of three categories of HPs in KwaZulu-Natal and has ...... tion, with good career opportunities which were similar in both urban and rural .... attract nurses to rural areas: A multicountry discrete choice.

  16. New Similarity Functions

    DEFF Research Database (Denmark)

    Yazdani, Hossein; Ortiz-Arroyo, Daniel; Kwasnicka, Halina

    2016-01-01

    spaces, in addition to their similarity in the vector space. Prioritized Weighted Feature Distance (PWFD) works similarly as WFD, but provides the ability to give priorities to desirable features. The accuracy of the proposed functions are compared with other similarity functions on several data sets....... Our results show that the proposed functions work better than other methods proposed in the literature....

  17. Phoneme Similarity and Confusability

    Science.gov (United States)

    Bailey, T.M.; Hahn, U.

    2005-01-01

    Similarity between component speech sounds influences language processing in numerous ways. Explanation and detailed prediction of linguistic performance consequently requires an understanding of these basic similarities. The research reported in this paper contrasts two broad classes of approach to the issue of phoneme similarity-theoretically…

  18. Krypton retention on solid adsorbents

    International Nuclear Information System (INIS)

    Monson, P.R. Jr.

    1981-08-01

    Over a dozen prospective adsorbents for krypton were studied and evaluated with respect to adsorption capacity and cost for dissolver off-gas streams from nuclear reprocessing plants. Results show that, at subambient temperature (-40 0 to -80 0 C), the commercially available hydrogen mordenite has sufficient adsorptive capacity to be the most cost-effective material studied. Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite. The results indicate that a solid adsorbent system is feasible and competitive with other developing systems whih utilize fluorocarbon absorption and cryogenic distillation

  19. Retention of long-term interim restorations with sodium fluoride enriched interim cement

    Science.gov (United States)

    Strash, Carolyn

    Purpose: Interim fixed dental prostheses, or "provisional restorations", are fabricated to restore teeth when definitive prostheses are made indirectly. Patients undergoing extensive prosthodontic treatment frequently require provisionalization for several months or years. The ideal interim cement would retain the restoration for as long as needed and still allow for ease of removal. It would also avoid recurrent caries by preventing demineralization of tooth structure. This study aims to determine if adding sodium fluoride varnish to interim cement may assist in the retention of interim restorations. Materials and methods: stainless steel dies representing a crown preparation were fabricated. Provisional crowns were milled for the dies using CAD/CAM technology. Crowns were provisionally cemented onto the dies using TempBond NE and NexTemp provisional cements as well as a mixture of TempBond NE and Duraphat fluoride varnish. Samples were stored for 24h then tested or thermocycled for 2500 or 5000 cycles before being tested. Retentive strength of each cement was recorded using a universal testing machine. Results: TempBond NE and NexTemp cements performed similarly when tested after 24h. The addition of Duraphat significantly decreased the retention when added to TempBond NE. NexTemp cement had high variability in retention over all tested time periods. Thermocycling for 2500 and 5000 cycles significantly decreased the retention of all cements. Conclusions: The addition of Duraphat fluoride varnish significantly decreased the retention of TempBond NE and is therefore not recommended for clinical use. Thermocycling significantly reduced the retention of TempBond NE and NexTemp. This may suggest that use of these cements for three months, as simulated in this study, is not recommended.

  20. Background or Experience? Using Logistic Regression to Predict College Retention

    Science.gov (United States)

    Synco, Tracee M.

    2012-01-01

    Tinto, Astin and countless others have researched the retention and attrition of students from college for more than thirty years. However, the six year graduation rate for all first-time full-time freshmen for the 2002 cohort was 57%. This study sought to determine the retention variables that predicted continued enrollment of entering freshmen…

  1. Secrets of Retention

    Science.gov (United States)

    Poliniak, Susan

    2012-01-01

    Recruiting students is one thing, but keeping them in a chorus, orchestra, or band is another. Although a music director has no control over some variables, there is much that can be done to help students to stay. Several experts share their advice on retention. One expert said a teacher's own attitude and classroom strategies may be two of the…

  2. Radionuclide Retention in Concrete Wasteforms

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Dawn M.; Jansik, Danielle P.; Golovich, Elizabeth C.; Cordova, Elsa A.

    2012-09-24

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of LLW and MLLW, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  3. American Recovery and Reinvestment Act of 2009: Final Report on Customer Acceptance, Retention, and Response to Time-Based Rates from Consumer Behavior Studies

    Energy Technology Data Exchange (ETDEWEB)

    Cappers, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Division; Scheer, Rich [Scheer Ventures LLC, Takoma Park, MD (United States)

    2018-03-07

    Time-based rate programs, enabled by utility investments in advanced metering infrastructure (AMI), are increasingly being considered by utilities as tools to reduce peak demand and enable customers to better manage consumption and costs. Under the Smart Grid Investment Grant Program (SGIG), the U.S. Department of Energy (DOE) partnered with several electric utilities to conduct consumer behavior studies (CBS). The goals involved applying randomized and controlled experimental designs for estimating customer responses more precisely and credibly to advance understanding of time-based rates and customer systems, and provide new information for improving program designs, implementation strategies, and evaluations. The intent was to produce more robust and credible analysis of impacts, costs, benefits, and lessons learned and assist utility and regulatory decision makers in evaluating investment opportunities involving time-based rates.

  4. Plant species richness enhances nitrogen retention in green roof plots.

    Science.gov (United States)

    Johnson, Catherine; Schweinhart, Shelbye; Buffam, Ishi

    2016-10-01

    Vegetated (green) roofs have become common in many cities and are projected to continue to increase in coverage, but little is known about the ecological properties of these engineered ecosystems. In this study, we tested the biodiversity-ecosystem function hypothesis using commercially available green roof trays as replicated plots with varying levels of plant species richness (0, 1, 3, or 6 common green roof species per plot, using plants with different functional characteristics). We estimated accumulated plant biomass near the peak of the first full growing season (July 2013) and measured runoff volume after nearly every rain event from September 2012 to September 2013 (33 events) and runoff fluxes of inorganic nutrients ammonium, nitrate, and phosphate from a subset of 10 events. We found that (1) total plant biomass increased with increasing species richness, (2) green roof plots were effective at reducing storm runoff, with vegetation increasing water retention more than soil-like substrate alone, but there was no significant effect of plant species identity or richness on runoff volume, (3) green roof substrate was a significant source of phosphate, regardless of presence/absence of plants, and (4) dissolved inorganic nitrogen (DIN = nitrate + ammonium) runoff fluxes were different among plant species and decreased significantly with increasing plant species richness. The variation in N retention was positively related to variation in plant biomass. Notably, the increased biomass and N retention with species richness in this engineered ecosystem are similar to patterns observed in published studies from grasslands and other well-studied ecosystems. We suggest that more diverse plantings on vegetated roofs may enhance the retention capacity for reactive nitrogen. This is of importance for the sustained health of vegetated roof ecosystems, which over time often experience nitrogen limitation, and is also relevant for water quality in receiving waters

  5. Liquid chromatography coupled to quadrupole-time of flight tandem mass spectrometry based quantitative structure-retention relationships of amino acid analogues derivatized via n-propyl chloroformate mediated reaction.

    Science.gov (United States)

    Kritikos, Nikolaos; Tsantili-Kakoulidou, Anna; Loukas, Yannis L; Dotsikas, Yannis

    2015-07-17

    In the current study, quantitative structure-retention relationships (QSRR) were constructed based on data obtained by a LC-(ESI)-QTOF-MS/MS method for the determination of amino acid analogues, following their derivatization via chloroformate esters. Molecules were derivatized via n-propyl chloroformate/n-propanol mediated reaction. Derivatives were acquired through a liquid-liquid extraction procedure. Chromatographic separation is based on gradient elution using methanol/water mixtures from a 70/30% composition to an 85/15% final one, maintaining a constant rate of change. The group of examined molecules was diverse, including mainly α-amino acids, yet also β- and γ-amino acids, γ-amino acid analogues, decarboxylated and phosphorylated analogues and dipeptides. Projection to latent structures (PLS) method was selected for the formation of QSRRs, resulting in a total of three PLS models with high cross-validated coefficients of determination Q(2)Y. For this reason, molecular structures were previously described through the use of descriptors. Through stratified random sampling procedures, 57 compounds were split to a training set and a test set. Model creation was based on multiple criteria including principal component significance and eigenvalue, variable importance, form of residuals, etc. Validation was based on statistical metrics Rpred(2),QextF2(2),QextF3(2) for the test set and Roy's metrics rm(Av)(2) and rm(δ)(2), assessing both predictive stability and internal validity. Based on aforementioned models, simplified equivalent were then created using a multi-linear regression (MLR) method. MLR models were also validated with the same metrics. The suggested models are considered useful for the estimation of retention times of amino acid analogues for a series of applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Retention of Emergency Care Knowledge.

    Science.gov (United States)

    Burckes, Mardie E.; Shao, Kung Ping Pam

    1984-01-01

    Data on the emergency care knowledge of college students were measured by a pretest, posttest, and retention test. A high relationship was found between students' posttest scores and retention test scores. Findings are discussed. (Author/DF)

  7. Retention performance of green roofs in three different climate regions

    Science.gov (United States)

    Sims, Andrew W.; Robinson, Clare E.; Smart, Charles C.; Voogt, James A.; Hay, Geoffrey J.; Lundholm, Jeremey T.; Powers, Brandon; O'Carroll, Denis M.

    2016-11-01

    Green roofs are becoming increasingly popular for moderating stormwater runoff in urban areas. This study investigated the impact different climates have on the retention performance of identical green roofs installed in London Ontario (humid continental), Calgary Alberta (semi-arid, continental), and Halifax Nova Scotia (humid, maritime). Drier climates were found to have greater percent cumulative stormwater retention with Calgary (67%) having significantly better percent retention than both London (48%) and Halifax (34%). However, over the same study period the green roof in London retained the greatest depth of stormwater (598 mm), followed by the green roof in Halifax (471 mm) and then Calgary (411 mm). The impact of climate was largest for medium sized storms where the antecedent moisture condition (AMC) at the beginning of a rainfall event governs retention performance. Importantly AMC was a very good predictor of stormwater retention, with similar retention at all three sites for a given AMC, emphasizing that AMC is a relevant indicator of retention performance in any climate. For large rainfall events (i.e., >45 mm) green roof average retention ranged between 16% and 29% in all cities. Overall, drier climates have superior retention due to lower AMC in the media. However, moderate and wet climates still provide substantial total volume reduction benefits.

  8. Retention of a 24-hour time memory in Syrian hamsters carrying the 20-hour short circadian period mutation in casein kinase-1ε (ck1εtau/tau).

    Science.gov (United States)

    Cain, Sean W; Yoon, Jeena; Shrestha, Tenjin C; Ralph, Martin R

    2014-10-01

    Circadian rhythmic expression of conditioned place avoidance (CPA) was produced in Syrian hamsters homozygous for the circadian short period mutation, tau. In constant dim red light neither the 20 h endogenous period, nor a 20 h place conditioning schedule eliminated the 24 h modulation of CPA behavior described previously for wild type (wt) hamsters and other species. Tau mutants exhibited a 20 h rhythm superimposed on the 24 h modulation. The 20 h component was removed selectively with lesions of the suprachiasmatic nucleus. Wt animals conditioned on a 20 h schedule did not produce a 20 h rhythm, but still expressed the 24 h modulation. The results show that the context entrainable oscillator (CEO) underlying memory for the timing of an unconditioned stimulus, retains a period of about 24 h regardless of clock gene background (tau mutation) and/or the conditioning schedule (24 vs 20 h). Therefore the CEO responsible for time memory is distinct from the biological clock controlling activity; the underlying circadian molecular mechanisms may differ from the ubiquitous transcription-translation feedback oscillator; and time memory itself is not classically conditioned. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Novel word retention in bilingual and monolingual speakers

    Directory of Open Access Journals (Sweden)

    Pui Fong eKan

    2014-09-01

    Full Text Available The goal of this research was to examine word retention in bilinguals and monolinguals. Long-term word retention is an essential part of vocabulary learning. Previous studies have documented that bilinguals outperform monolinguals in terms of retrieving newly-exposed words. Yet, little is known about whether or to what extent bilinguals are different from monolinguals in word retention. Participants were 30 English-speaking monolingual adults and 30 bilingual adults who speak Spanish as a home language and learned English as a second language during childhood. In a previous study (Kan, Sadagopan, Janich, & Andrade, 2014, the participants were exposed to the target novel words in English, Spanish, and Cantonese. In this current study, word retention was measured a week after the fast mapping task. No exposures were given during the one-week interval. Results showed that bilinguals and monolinguals retain a similar number of words. However, participants produced more words in English than in either Spanish or Cantonese. Correlation analyses revealed that language knowledge plays a role in the relationships between fast mapping and word retention. Specifically, within- and across-language relationships between bilinguals’ fast mapping and word retention were found in Spanish and English, by contrast, within-language relationships between monolinguals’ fast mapping and word retention were found in English and across-language relationships between their fast mapping and word retention performance in English and Cantonese. Similarly, bilinguals differed from monolinguals in the relationships among the word retention scores in three languages. Significant correlations were found among bilinguals’ retention scores. However, no such correlations were found among monolinguals’ retention scores. The overall findings suggest that bilinguals’ language experience and language knowledge most likely contribute to how they learn and retain new words.

  10. Novel word retention in bilingual and monolingual speakers.

    Science.gov (United States)

    Kan, Pui Fong; Sadagopan, Neeraja

    2014-01-01

    The goal of this research was to examine word retention in bilinguals and monolinguals. Long-term word retention is an essential part of vocabulary learning. Previous studies have documented that bilinguals outperform monolinguals in terms of retrieving newly-exposed words. Yet, little is known about whether or to what extent bilinguals are different from monolinguals in word retention. Participants were 30 English-speaking monolingual adults and 30 bilingual adults who speak Spanish as a home language and learned English as a second language during childhood. In a previous study (Kan et al., 2014), the participants were exposed to the target novel words in English, Spanish, and Cantonese. In this current study, word retention was measured a week after the fast mapping task. No exposures were given during the one-week interval. Results showed that bilinguals and monolinguals retain a similar number of words. However, participants produced more words in English than in either Spanish or Cantonese. Correlation analyses revealed that language knowledge plays a role in the relationships between fast mapping and word retention. Specifically, within- and across-language relationships between bilinguals' fast mapping and word retention were found in Spanish and English, by contrast, within-language relationships between monolinguals' fast mapping and word retention were found in English and across-language relationships between their fast mapping and word retention performance in English and Cantonese. Similarly, bilinguals differed from monolinguals in the relationships among the word retention scores in three languages. Significant correlations were found among bilinguals' retention scores. However, no such correlations were found among monolinguals' retention scores. The overall findings suggest that bilinguals' language experience and language knowledge most likely contribute to how they learn and retain new words.

  11. Molecular similarity measures.

    Science.gov (United States)

    Maggiora, Gerald M; Shanmugasundaram, Veerabahu

    2011-01-01

    Molecular similarity is a pervasive concept in chemistry. It is essential to many aspects of chemical reasoning and analysis and is perhaps the fundamental assumption underlying medicinal chemistry. Dissimilarity, the complement of similarity, also plays a major role in a growing number of applications of molecular diversity in combinatorial chemistry, high-throughput screening, and related fields. How molecular information is represented, called the representation problem, is important to the type of molecular similarity analysis (MSA) that can be carried out in any given situation. In this work, four types of mathematical structure are used to represent molecular information: sets, graphs, vectors, and functions. Molecular similarity is a pairwise relationship that induces structure into sets of molecules, giving rise to the concept of chemical space. Although all three concepts - molecular similarity, molecular representation, and chemical space - are treated in this chapter, the emphasis is on molecular similarity measures. Similarity measures, also called similarity coefficients or indices, are functions that map pairs of compatible molecular representations that are of the same mathematical form into real numbers usually, but not always, lying on the unit interval. This chapter presents a somewhat pedagogical discussion of many types of molecular similarity measures, their strengths and limitations, and their relationship to one another. An expanded account of the material on chemical spaces presented in the first edition of this book is also provided. It includes a discussion of the topography of activity landscapes and the role that activity cliffs in these landscapes play in structure-activity studies.

  12. Effects of changing pH, incubation time, and As(V) competition, on F- retention on soils, natural adsorbents, by-products, and waste materials

    Science.gov (United States)

    Quintáns-Fondo, Ana; Santás-Miguel, Vanesa; Nóvoa-Muñoz, Juan C.; Arias-Estévez, Manuel; Fernández-Sanjurjo, María J.; Álvarez-Rodríguez, Esperanza; Núñez-Delgado, Avelino

    2018-03-01

    The purpose of this work was to elucidate the repercussion of changing pH, incubation time and As(V) competition on fluoride (F-) sorption on forest and vineyard soil samples, pyritic and granitic materials, as well as on the by-products pine sawdust, oak wood ash, mussel shell ash, fine and coarse mussel shell, and slate processing waste fines. To reach this end, the methodological approach was based on batch-type experiments. The results indicate that, for most materials, F- sorption was very high at the start, but was clearly diminished when the pH value increased. However, oak wood ash and shell ash showed high F- sorption even at alkaline pH, and pine sawdust showed low F- sorption for any pH value. Specifically, F- sorption was close to 100% for both ashes at pH time on F- sorption, it was very low for both soils, pyritic material, granitic material and both kinds of ashes, as all of them showed very rapid F- sorption from the start, with differences being lesser than 10% between sorption at 30 min and 1 month of incubation. However, sawdust and slate fines sorbed 20% of added F- in 30 minutes, remaining constant up to twelve hours, and doubling after 30 days. And finally, mussel shell sorbed 20% at 30 minutes, increasing to close to 60% when incubation time was 30 days. This means that some of the materials showed a first sorption phase characterized by rapid F- sorption, and a slower sorption in a second phase. As regards the effect of the presence of As(V) on F- sorption, it was almost negligible, indicating the absence of competition for sorption sites. In view of that all, these results could aid to appropriately manage soils and by-products when focusing on F- removal, in circumstances where pH value changes, contact time vary from hours to days, and potential competition between F- and As(V) could take place.

  13. Enhancing retention of partial dentures using elastomeric retention rings

    Directory of Open Access Journals (Sweden)

    Kakkirala Revathi

    2015-01-01

    Full Text Available This report presents an alternative method for the retention of partial dentures that relies on the engagement of tooth undercuts by a lining material. The lab procedures are also presented. A new maxillary and mandibular acrylic partial dentures were fabricated using elastomeric retention technique for a partially dentate patient. A partially dentate man reported difficulty in retaining his upper removable partial denture (RPD. The maxillary RPD was designed utilizing elastomeric retention technique. During follow-up, it was necessary to replace the retention rings due to wear. The replacement of the retention rings, in this case, was done through a chairside reline technique. Elastomeric retention technique provides exceptionally good retention can be indicated to stabilize, cushion, splint periodontally involved teeth, no enough undercut for clasps, eliminate extractions, single or isolated teeth.

  14. Processes of Similarity Judgment

    Science.gov (United States)

    Larkey, Levi B.; Markman, Arthur B.

    2005-01-01

    Similarity underlies fundamental cognitive capabilities such as memory, categorization, decision making, problem solving, and reasoning. Although recent approaches to similarity appreciate the structure of mental representations, they differ in the processes posited to operate over these representations. We present an experiment that…

  15. Judgments of brand similarity

    NARCIS (Netherlands)

    Bijmolt, THA; Wedel, M; Pieters, RGM; DeSarbo, WS

    This paper provides empirical insight into the way consumers make pairwise similarity judgments between brands, and how familiarity with the brands, serial position of the pair in a sequence, and the presentation format affect these judgments. Within the similarity judgment process both the

  16. Job embeddedness: a theoretical foundation for developing a comprehensive nurse retention plan.

    Science.gov (United States)

    Holtom, Brooks C; O'Neill, Bonnie S

    2004-05-01

    Using a new construct, job embeddedness, from the business management literature, this study first examines its value in predicting employee retention in a healthcare setting and second, assesses whether the factors that influence the retention of nurses are systematically different from those influencing other healthcare workers. The shortage of skilled healthcare workers makes it imperative that healthcare providers develop effective recruitment and retention plans. With nursing turnover averaging more than 20% a year and competition to hire new nurses fierce, many administrators rightly question whether they should develop specialized plans to recruit and retain nurses. A longitudinal research design was employed to assess the predictive validity of the job embeddedness concept. At time 1, surveys were mailed to a random sample of 500 employees of a community-based hospital in the Northwest region of the United States. The survey assessed personal characteristics, job satisfaction, organizational commitment, job embeddedness, job search, perceived alternatives, and intent to leave. One year later (time 2) the organization provided data regarding voluntary leavers from the hospital. Hospital employees returned 232 surveys, yielding a response rate of 46.4 %. The results indicate that job embeddedness predicted turnover over and beyond a combination of perceived desirability of movement measures (job satisfaction, organizational commitment) and perceived ease of movement measures (job alternatives, job search). Thus, job embeddedness assesses new and meaningful variance in turnover in excess of that predicted by the major variables included in almost all the major models of turnover. The findings suggest that job embeddedness is a valuable lens through which to evaluate employee retention in healthcare organizations. Further, the levers for influencing retention are substantially similar for nurses and other healthcare workers. Implications of these findings and

  17. Retention prediction of highly polar ionizable solutes under gradient conditions on a mixed-mode reversed-phase and weak anion-exchange stationary phase.

    Science.gov (United States)

    Balkatzopoulou, P; Fasoula, S; Gika, H; Nikitas, P; Pappa-Louisi, A

    2015-05-29

    In the present work the retention of three highly polar and ionizable solutes - uric acid, nicotinic acid and ascorbic acid - was investigated on a mixed-mode reversed-phase and weak anion-exchange (RP/WAX) stationary phase in buffered aqueous acetonitrile (ACN) mobile phases. A U-shaped retention behavior was observed for all solutes with respect to the eluent organic modifier content studied in a range of 5-95% (v/v). This retention behavior clearly demonstrates the presence of a HILIC-type retention mechanism at ACN-rich hydro-organic eluents and an RP-like retention at aqueous-rich hydro-organic eluents. Hence, this column should be promising for application under both RP and HILIC gradient elution modes. For this reason, a series of programmed elution runs were carried out with increasing (RP) and decreasing (HILIC) organic solvent concentration in the mobile phase. This dual gradient process was successfully modeled by two retention models exhibiting a quadratic or a cubic dependence of the logarithm of the solute retention factor (lnk) upon the organic modifier volume fraction (φ). It was found that both models produced by gradient retention data allow the prediction of solute retention times for both types of programmed elution on the mixed-mode column. Four, in the case of the quadratic model, or five, in the case of the cubic model, initial HILIC- and RP-type gradient runs gave satisfactory retention predictions of any similar kind elution program, even with different flow rate, with an overall error of only 2.5 or 1.7%, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. The semantic similarity ensemble

    Directory of Open Access Journals (Sweden)

    Andrea Ballatore

    2013-12-01

    Full Text Available Computational measures of semantic similarity between geographic terms provide valuable support across geographic information retrieval, data mining, and information integration. To date, a wide variety of approaches to geo-semantic similarity have been devised. A judgment of similarity is not intrinsically right or wrong, but obtains a certain degree of cognitive plausibility, depending on how closely it mimics human behavior. Thus selecting the most appropriate measure for a specific task is a significant challenge. To address this issue, we make an analogy between computational similarity measures and soliciting domain expert opinions, which incorporate a subjective set of beliefs, perceptions, hypotheses, and epistemic biases. Following this analogy, we define the semantic similarity ensemble (SSE as a composition of different similarity measures, acting as a panel of experts having to reach a decision on the semantic similarity of a set of geographic terms. The approach is evaluated in comparison to human judgments, and results indicate that an SSE performs better than the average of its parts. Although the best member tends to outperform the ensemble, all ensembles outperform the average performance of each ensemble's member. Hence, in contexts where the best measure is unknown, the ensemble provides a more cognitively plausible approach.

  19. The influence of age at time of exposure to 239Pu or 226Ra on retention, distribution, survival and tumor induction in Beagles

    International Nuclear Information System (INIS)

    Bruenger, F.W.; Miller, S.C.; Lloyd, R.D.

    1991-01-01

    The influence of age at injection of 226 Ra or 239 Pu on skeletal deposition and local distribution, the pattern of bone tumor formation and post-injection survival were studied in parallel short-term mechanistic and lifetime toxicity experiments. Beagles received a single intravenous injection of 226 Ra or 239 Pu at age 3 months (juveniles), 17-19 months (young adults) or 60 months (mature). Data from short-term mechanistic-dosimetric studies and from one dosage level (41 kBq 226 Ra/kg or 11 kBq 239 Pu/kg body mass) of each of the toxicity experiments were compared. Skeletal growth and turnover produced differential initial deposition and distribution patterns typical for each age group. The highest bone tumor incidence was seen in the young adult groups. Differences were observed in bone tumor location between dogs in the same age group given radium or plutonium and among age groups injected with either radionuclide, and some of these could be explained by differences in local dose distributions (e.g., trabecular vs. cortical bone). Cox regression indicated no significant differences in post-injection survivals (uncorrected for the different pre-injection periods) of Ra-injected groups, but there was a statistically significant difference among the Pu-injected groups. Neutron-induced autoradiography showed that differences in the effects of Pu in the three age groups were due primarily to the age- and time-dependent local distribution of the nuclide

  20. Exploitation of rapid acidification phenomena of food waste in reducing the hydraulic retention time (HRT) of high rate anaerobic digester without conceding on biogas yield.

    Science.gov (United States)

    Kuruti, Kranti; Begum, Sameena; Ahuja, Shruti; Anupoju, Gangagni Rao; Juntupally, Sudharshan; Gandu, Bharath; Ahuja, Devender Kumar

    2017-02-01

    The aim of the present work was to study and infer a full scale experience on co-digestion of 1000kg of FW (400kg cooked food waste and 600kg uncooked food waste) and 2000L of rice gruel (RG) on daily basis based on a high rate biomethanation technology called "Anaerobic gas lift reactor" (AGR). The pH of raw substrate was low (5.2-5.5) that resulted in rapid acidification phenomena with in 12h in the feed preparation tank that facilitated to obtain a lower hydraulic residence time (HRT) of 10days. At full load, AGR was fed with 245kg of total solids, 205kg of volatile solids (167kg of organic matter in terms of chemical oxygen demand) which resulted in the generation of biogas and bio manure of 140m 3 /day and 110kg/day respectively. The produced biogas replaced 60-70kg of LPG per day. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Retention of anatomy knowledge by student radiographers

    International Nuclear Information System (INIS)

    Hall, A. Susanne; Durward, Brian R.

    2009-01-01

    Introduction: Anatomy has long been regarded as an integral part of the core curriculum. However, anecdotal evidence suggests that long-term retention of anatomy knowledge may be deficient. This study aims to evidence whether student radiographers demonstrate the same level of knowledge of anatomy after a period of time has elapsed and to correlate to approaches to learning and studying. Methodology: A repeated measures design was utilised to measure retention of anatomy knowledge for both MCQs and short-response answers to a Practical Radiographic Anatomy Examination; alpha value p < 0.05. Fifty-one students from levels 2 and 3 were retested after a time lapse of 10 and 22 months respectively. The students were not aware that their knowledge was being retested. Approaches to learning and studying were measured using the ASSIST inventory. Results: Statistical analysis found no difference in performance on MCQ assessment, in either the combined sample or levels 2 and 3 separately, from baseline to retention occasions; average retention rate being 99%. However, a statistical difference in performance on PRAE assessment was found, with level 2 experiencing a larger reduction in scores; retention rate of 67% compared to level 3 at 77%. The students perceived themselves to be principally strategic in their approach to learning and studying but no strong relationships were found when correlated to test scores. Conclusion: The student radiographers in this study demonstrated varied anatomy retention rates dependent on assessment method employed and time interval that had elapsed. It is recommended that diverse teaching and assessment strategies are adopted to encourage a deeper approach to learning and studying.

  2. Retention of gaseous isotopes

    International Nuclear Information System (INIS)

    Yarbro, O.O.; Mailen, J.C.; Stephenson, M.J.

    1977-01-01

    Retention of gaseous fission products during fuel reprocessing has, in the past, been limited to a modest retention of 131 I when processing fuels decayed less than about 180 days. The projected rapid growth of the nuclear power industry along with a desire to minimize environmental effects is leading to the reassessment of requirements for retention of gaseous fission products, including 131 I, 129 I, 85 Kr, 3 H, and 14 C. Starting in the late 1960s, a significant part of the LMFBR reprocessing development program has been devoted to understanding the behavior of gaseous fission products in plant process and effluent streams and the development of advanced systems for their removal. Systems for iodine control include methods for evolving up to 99% of the iodine from dissolver solutions to minimize its introduction and distribution throughout downstream equipment. An aqueous scrubbing system (Iodox) using 20 M HNO 3 as the scrubbing media effectively removes all significant iodine forms from off-gas streams while handling the kilogram quantities of iodine present in head-end and dissolver off-gas streams. Silver zeolite is very effective for removing iodine forms at low concentration from the larger-volume plant off-gas streams. Removal of iodine from plant liquid effluents by solid sorbents either prior to or following final vaporization appears feasible. Krypton is effectively released during dissolution and can be removed from the relatively small volume head-end and dissolver off-gas stream. Two methods appear applicable for removal and concentration of krypton: (1) selective absorption in fluorocarbons, and (2) cryogenic absorption in liquid nitrogen. The fluorocarbon absorption process appears to be rather tolerant of the normal contaminants (H 2 O, CO 2 , NOsub(x), and organics) present in typical reprocessing plant off-gas whereas the cryogenic system requires an extensive feed gas pretreatment system. Retention of tritium in a reprocessing plant is

  3. Early retention of 237Pu + 239Pu in mature beagles

    International Nuclear Information System (INIS)

    Lloyd, R.D.; McFarland, S.S.; Atherton, D.R.; Bruenger, F.W.; Taylor, G.N.; Mays, C.W.

    1978-01-01

    Five mature beagles, ranging in age from 57 to 84 months, were injected intravenously with about 0.05-0.1 μCi/kg of 239 Pu(IV) citrate to which tracer amounts of the photon-emitter 237 Pu had been added. Plutonium retention in liver and in non-liver tissue (mainly skeleton) was measured periodically in the living dogs for nearly 4 months after injection by a combination of total-body and partial-body counting. All excreta were collected during the first 21 days and analysed for their Pu content. One dog was sacrificed at 14 days and another at 118 days for distribution studies. About 17% (14-20%) of the injected Pu was excreted in the urine and feces in the first 3 weeks, about the same as that excreted in a corresponding time by beagles injected as young adults (14%), but substantially more than beagles injected as juveniles (11%). In contrasts to juvenile beagles injected at 3 months of age, in which early retention was about 12% in liver and 68% in the skeleton, mature beagles retained about 30% in liver and 50% in the skeleton. Retention in young adult beagles injected at 17 months of age was similar to that of mature dogs. Relative distribution of skeletal plutonium among various bones was similar in the mature animals to that seen previously in young adults, but quite different from that of juveniles. A notable exception was the humerus for which there was no significant difference (P>0.2) in the % of retained skeletal Pu represented by the humerus among the juvenile, young adult and mature dogs. (author)

  4. Gender similarities and differences.

    Science.gov (United States)

    Hyde, Janet Shibley

    2014-01-01

    Whether men and women are fundamentally different or similar has been debated for more than a century. This review summarizes major theories designed to explain gender differences: evolutionary theories, cognitive social learning theory, sociocultural theory, and expectancy-value theory. The gender similarities hypothesis raises the possibility of theorizing gender similarities. Statistical methods for the analysis of gender differences and similarities are reviewed, including effect sizes, meta-analysis, taxometric analysis, and equivalence testing. Then, relying mainly on evidence from meta-analyses, gender differences are reviewed in cognitive performance (e.g., math performance), personality and social behaviors (e.g., temperament, emotions, aggression, and leadership), and psychological well-being. The evidence on gender differences in variance is summarized. The final sections explore applications of intersectionality and directions for future research.

  5. Volatilizable Biogenic Organic Compounds (VBOCs with two dimensional Gas Chromatography-Time of Flight Mass Spectrometry (GC × GC-TOFMS: sampling methods, VBOC complexity, and chromatographic retention data

    Directory of Open Access Journals (Sweden)

    C. Chen

    2012-02-01

    Full Text Available Two dimensional gas chromatography (GC × GC with detection by time-of-flight mass spectrometry (TOFMS was applied in the rapid analysis of air samples containing highly complex mixtures of volatilizable biogenic organic compounds (VBOCs. VBOC analytical methodologies are briefly reviewed, and optimal conditions are discussed for sampling with both adsorption/thermal desorption (ATD cartridges and solid-phase microextraction (SPME fibers. Air samples containing VBOC emissions from leaves of two tree species (Cedrus atlantica and Calycolpus moritzianus were obtained by both ATD and SPME. The optimized gas chromatographic conditions utilized a 45 m, 0.25 mm I.D. low-polarity primary column (DB-VRX, 1.4 μm film and a 1.5 m, 0.25 mm I.D. polar secondary column (StabilwaxTM, 0.25 μm film. Excellent separation was achieved in a 36 min temperature programmed GC × GC chromatogram. Thousands of VBOC peaks were present in the sample chromatograms; hundreds of tentative identifications by NIST mass spectral matching are provided. Very few of the tentatively identified compounds are currently available as authentic standards. Minimum detection limit values for a 5 l ATD sample were 3.5 pptv (10 ng m−3 for isoprene, methyl vinyl ketone, and methacrolein, and ~1.5 pptv (~10 ng m−3 for monoterpenes and sesquiterpenes. Kovats-type chromatographic retention index values on the primary column and relative retention time values on the secondary column are provided for 21 standard compounds and for 417 tentatively identified VBOCs. 19 of the 21 authentic standard compounds were found in one of the Cedrus atlantica SPME samples. In addition, easily quantifiable levels of at least 13 sesquiterpenes were found in an ATD sample obtained from a branch enclosure of Calycolpus moritzianus. Overall, the results obtained via GC × GC-TOFMS highlight an extreme, and largely uncharacterized diversity of VBOCs, consistent with the hypothesis that sesquiterpenes and

  6. Volatilizable Biogenic Organic Compounds (VBOCs) with two dimensional Gas Chromatography-Time of Flight Mass Spectrometry (GC × GC-TOFMS): sampling methods, VBOC complexity, and chromatographic retention data

    Science.gov (United States)

    Pankow, J. F.; Luo, W.; Melnychenko, A. N.; Barsanti, K. C.; Isabelle, L. M.; Chen, C.; Guenther, A. B.; Rosenstiel, T. N.

    2012-02-01

    Two dimensional gas chromatography (GC × GC) with detection by time-of-flight mass spectrometry (TOFMS) was applied in the rapid analysis of air samples containing highly complex mixtures of volatilizable biogenic organic compounds (VBOCs). VBOC analytical methodologies are briefly reviewed, and optimal conditions are discussed for sampling with both adsorption/thermal desorption (ATD) cartridges and solid-phase microextraction (SPME) fibers. Air samples containing VBOC emissions from leaves of two tree species (Cedrus atlantica and Calycolpus moritzianus) were obtained by both ATD and SPME. The optimized gas chromatographic conditions utilized a 45 m, 0.25 mm I.D. low-polarity primary column (DB-VRX, 1.4 μm film) and a 1.5 m, 0.25 mm I.D. polar secondary column (StabilwaxTM, 0.25 μm film). Excellent separation was achieved in a 36 min temperature programmed GC × GC chromatogram. Thousands of VBOC peaks were present in the sample chromatograms; hundreds of tentative identifications by NIST mass spectral matching are provided. Very few of the tentatively identified compounds are currently available as authentic standards. Minimum detection limit values for a 5 l ATD sample were 3.5 pptv (10 ng m-3) for isoprene, methyl vinyl ketone, and methacrolein, and ~1.5 pptv (~10 ng m-3) for monoterpenes and sesquiterpenes. Kovats-type chromatographic retention index values on the primary column and relative retention time values on the secondary column are provided for 21 standard compounds and for 417 tentatively identified VBOCs. 19 of the 21 authentic standard compounds were found in one of the Cedrus atlantica SPME samples. In addition, easily quantifiable levels of at least 13 sesquiterpenes were found in an ATD sample obtained from a branch enclosure of Calycolpus moritzianus. Overall, the results obtained via GC × GC-TOFMS highlight an extreme, and largely uncharacterized diversity of VBOCs, consistent with the hypothesis that sesquiterpenes and other compounds

  7. Chromatographic fingerprint similarity analysis for pollutant source identification

    International Nuclear Information System (INIS)

    Xie, Juan-Ping; Ni, Hong-Gang

    2015-01-01

    In the present study, a similarity analysis method was proposed to evaluate the source-sink relationships among environmental media for polybrominated diphenyl ethers (PBDEs), which were taken as the representative contaminants. Chromatographic fingerprint analysis has been widely used in the fields of natural products chemistry and forensic chemistry, but its application to environmental science has been limited. We established a library of various sources of media containing contaminants (e.g., plastics), recognizing that the establishment of a more comprehensive library allows for a better understanding of the sources of contamination. We then compared an environmental complex mixture (e.g., sediment, soil) with the profiles in the library. These comparisons could be used as the first step in source tracking. The cosine similarities between plastic and soil or sediment ranged from 0.53 to 0.68, suggesting that plastic in electronic waste is an important source of PBDEs in the environment, but it is not the only source. A similarity analysis between soil and sediment indicated that they have a source-sink relationship. Generally, the similarity analysis method can encompass more relevant information of complex mixtures in the environment than a profile-based approach that only focuses on target pollutants. There is an inherent advantage to creating a data matrix containing all peaks and their relative levels after matching the peaks based on retention times and peak areas. This data matrix can be used for source identification via a similarity analysis without quantitative or qualitative analysis of all chemicals in a sample. - Highlights: • Chromatographic fingerprint analysis can be used as the first step in source tracking. • Similarity analysis method can encompass more relevant information of pollution. • The fingerprints strongly depend on the chromatographic conditions. • A more effective and robust method for identifying similarities is required

  8. Mentoring: the retention factor in the acute care setting.

    Science.gov (United States)

    Funderburk, Amy E

    2008-01-01

    The most difficult time to retain staff nurses can be the first year after hire. Because of the high costs of recruitment and orientation, retention of these new employees is essential. Mentoring is a viable retention tool for the new employee and for existing experienced nurses. Mentoring also provides professional growth benefits that appeal to existing employees and increase their job enjoyment and satisfaction.

  9. Gamma-variate plasma clearance versus urinary plasma clearance of 51Cr-EDTA in patients with cirrhosis with and without fluid retention

    DEFF Research Database (Denmark)

    Fuglsang, Stefan; Henriksen, Ulrik L; Hansen, Hanne Boskov

    2017-01-01

    In patients with fluid retention, the plasma clearance of (51) Cr-EDTA (Clexp obtained by multiexponential fit) may overestimate the glomerular filtration rate (GFR). The present study was undertaken to compare a gamma-variate plasma clearance (Clgv) with the urinary plasma clearance of (51) Cr......-EDTA (Clu ) in patients with cirrhosis with and without fluid retention. A total of 81 patients with cirrhosis (22 without fluid retention, 59 with ascites) received a quantitative intravenous injection of (51) Cr-EDTA followed by plasma and quantitative urinary samples for 5 h. Clgv was determined from...... the injected dose relative to the plasma concentration-time area, obtained by a gamma-variate iterative fit. Clexp and Clu were determined by standard technique. In patients without fluid retention, Clgv , Clexp and Clu were closely similar. The difference between Clgv and Clu (Clgv - Clu = ΔCl) was mean -0...

  10. Search Improvement Process-Chaotic Optimization-Particle Swarm Optimization-Elite Retention Strategy and Improved Combined Cooling-Heating-Power Strategy Based Two-Time Scale Multi-Objective Optimization Model for Stand-Alone Microgrid Operation

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2017-11-01

    Full Text Available The optimal dispatching model for a stand-alone microgrid (MG is of great importance to its operation reliability and economy. This paper aims at addressing the difficulties in improving the operational economy and maintaining the power balance under uncertain load demand and renewable generation, which could be even worse in such abnormal conditions as storms or abnormally low or high temperatures. A new two-time scale multi-objective optimization model, including day-ahead cursory scheduling and real-time scheduling for finer adjustments, is proposed to optimize the operational cost, load shedding compensation and environmental benefit of stand-alone MG through controllable load (CL and multi-distributed generations (DGs. The main novelty of the proposed model is that the synergetic response of CL and energy storage system (ESS in real-time scheduling offset the operation uncertainty quickly. And the improved dispatch strategy for combined cooling-heating-power (CCHP enhanced the system economy while the comfort is guaranteed. An improved algorithm, Search Improvement Process-Chaotic Optimization-Particle Swarm Optimization-Elite Retention Strategy (SIP-CO-PSO-ERS algorithm with strong searching capability and fast convergence speed, was presented to deal with the problem brought by the increased errors between actual renewable generation and load and prior predictions. Four typical scenarios are designed according to the combinations of day types (work day or weekend and weather categories (sunny or rainy to verify the performance of the presented dispatch strategy. The simulation results show that the proposed two-time scale model and SIP-CO-PSO-ERS algorithm exhibit better performance in adaptability, convergence speed and search ability than conventional methods for the stand-alone MG’s operation.

  11. Similarity or difference?

    DEFF Research Database (Denmark)

    Villadsen, Anders Ryom

    2013-01-01

    While the organizational structures and strategies of public organizations have attracted substantial research attention among public management scholars, little research has explored how these organizational core dimensions are interconnected and influenced by pressures for similarity....... In this paper I address this topic by exploring the relation between expenditure strategy isomorphism and structure isomorphism in Danish municipalities. Different literatures suggest that organizations exist in concurrent pressures for being similar to and different from other organizations in their field......-shaped relation exists between expenditure strategy isomorphism and structure isomorphism in a longitudinal quantitative study of Danish municipalities....

  12. Comparing Harmonic Similarity Measures

    NARCIS (Netherlands)

    de Haas, W.B.; Robine, M.; Hanna, P.; Veltkamp, R.C.; Wiering, F.

    2010-01-01

    We present an overview of the most recent developments in polyphonic music retrieval and an experiment in which we compare two harmonic similarity measures. In contrast to earlier work, in this paper we specifically focus on the symbolic chord description as the primary musical representation and

  13. Does skill retention benefit from retentivity and symbolic rehearsal? - two studies with a simulated process control task.

    Science.gov (United States)

    Kluge, Annette; Frank, Barbara; Maafi, Sanaz; Kuzmanovska, Aleksandra

    2016-05-01

    Two experiments were designed to compare two symbolic rehearsal refresher interventions (imaginary practice, a hidden introspective process) and investigate the role of retentivity in skill retention. Retentivity is investigated as the ability to memorise and reproduce information and associations that were learned a short time ago. Both experiments comprised initial training (week 1), a symbolic rehearsal for the experimental group (week 2) and a retention assessment (week 3). In the first study, the experimental group received a symbolic rehearsal, while the control group received no rehearsal. In the second study, the experimental group received the same symbolic rehearsal used in study 1, enhanced with rehearsal tasks addressing human-computer interaction. The results showed that both symbolic rehearsal interventions were equally likely to mitigate skill decay. The retentivity showed medium to high correlations with skill retention in both studies, and the results suggest that subjects high in retentivity benefit more from a symbolic rehearsal refresher intervention. Practitioner Summary: Skill decay becomes a problem in situations in which jobs require the correct mastery of non-routine situations. Two experimental studies with simulated process control tasks showed that symbolic rehearsal and retentivity can significantly mitigate skill decay and that subjects higher in retentivity benefit more from refresher interventions.

  14. Factors affecting the initial adhesion and retention of the plant pathogen Xylella fastidiosa in the foregut of an insect vector.

    Science.gov (United States)

    Killiny, Nabil; Almeida, Rodrigo P P

    2014-01-01

    Vector transmission of bacterial plant pathogens involves three steps: pathogen acquisition from an infected host, retention within the vector, and inoculation of cells into susceptible tissue of an uninfected plant. In this study, a combination of plant and artificial diet systems were used to determine the importance of several genes on the initial adhesion and retention of the bacterium Xylella fastidiosa to an efficient insect vector. Mutant strains included fimbrial (fimA and pilB) and afimbrial (hxfA and hxfB) adhesins and three loci involved in regulatory systems (rpfF, rpfC, and cgsA). Transmission assays with variable retention time indicated that HxfA and HxfB were primarily important for early adhesion to vectors, while FimA was necessary for both adhesion and retention. The long pilus protein PilB was not deficient in initial adhesion but may be important for retention. Genes upregulated under the control of rpfF are important for both initial adhesion and retention, as transmission rates of this mutant strain were initially low and decreased over time, while disruption of rpfC and cgsA yielded trends similar to that shown by the wild-type control. Because induction of an X. fastidiosa transmissible state requires pectin, a series of experiments were used to test the roles of a polygalacturonase (pglA) and the pectin and galacturonic acid carbohydrates on the transmission of X. fastidiosa. Results show that galacturonic acid, or PglA activity breaking pectin into its major subunit (galacturonic acid), is required for X. fastidiosa vector transmission using an artificial diet system. This study shows that early adhesion and retention of X. fastidiosa are mediated by different factors. It also illustrates that the interpretation of results of vector transmission experiments, in the context of vector-pathogen interaction studies, is highly dependent on experimental design.

  15. NOx retention in scrubbing column

    International Nuclear Information System (INIS)

    Nakazone, A.K.; Costa, R.E.; Lobao, A.S.T.; Matsuda, H.T.; Araujo, B.F.

    1988-07-01

    During the UO 2 dissolution in nitric acid, some different species of NO x are released. The off gas can either be refluxed to the dissolver or be released and retained on special columns. The final composition of the solution is the main parameter to take in account. A process for nitrous gases retention using scubber columns containing H 2 O or diluted HNO 3 is presented. Chemiluminescence measurement was employed to NO x evalution before and after scrubbing. Gas flow, temperature, residence time are the main parameters considered in this paper. For the dissolution of 100g UO 2 in 8M nitric acid, a 6NL/h O 2 flow was the best condition for the NO/NO 2 oxidation with maximum adsorption in the scrubber columns. (author) [pt

  16. Age influence on retention, distribution and internal doses of 85Sr in rat

    International Nuclear Information System (INIS)

    Tian Wuxun; Wang Decheng; Zhang Hongyuan

    1990-01-01

    After I.V. 85 Sr, the whole body 85 Sr-retentions in rats were fit to two compartment exponential equations. The equation parameters showed a significantly difference between the young group and both the adult and old groups (p 2 ) for 85 Sr in the slow compartment decreased in regular order from the young to the old groups. In the bone 85 Sr-retention equations Tb 2 of the slow compartment for 85 Sr in the young group was significantly lower than the adult and old groups. The doses of the whole body and red-marrow for young rats were 4.2 times as much as those of adult rats, and 6.2 and 5.9 times as much as those old rats. The dose-cumulative speeds was most quick in the young groups and similar in the adult and the old

  17. Retention capacity of correlated surfaces.

    Science.gov (United States)

    Schrenk, K J; Araújo, N A M; Ziff, R M; Herrmann, H J

    2014-06-01

    We extend the water retention model [C. L. Knecht et al., Phys. Rev. Lett. 108, 045703 (2012)] to correlated random surfaces. We find that the retention capacity of discrete random landscapes is strongly affected by spatial correlations among the heights. This phenomenon is related to the emergence of power-law scaling in the lake volume distribution. We also solve the uncorrelated case exactly for a small lattice and present bounds on the retention of uncorrelated landscapes.

  18. Retention capacity of correlated surfaces

    OpenAIRE

    Schrenk, K. J.; Araújo, N. A. M.; Ziff, R. M.; Herrmann, H. J.

    2014-01-01

    We extend the water retention model [C. L. Knecht et al., Phys. Rev. Lett. 108, 045703 (2012)] to correlated random surfaces. We find that the retention capacity of discrete random landscapes is strongly affected by spatial correlations among the heights. This phenomenon is related to the emergence of power-law scaling in the lake volume distribution. We also solve the uncorrelated case exactly for a small lattice and present bounds on the retention of uncorrelated landscapes.

  19. Nitrogen Saturation in Highly Retentive Watersheds?

    Science.gov (United States)

    Daley, M. L.; McDowell, W. H.

    2009-12-01

    Watershed managers are often concerned with minimizing the amount of N delivered to N-limited estuaries and coastal zones. A major concern is that watersheds might reach N saturation, in which N delivered to coastal zones increases due to declines in the efficiency of N retention despite constant or even reduced N inputs. We have quantified long-term changes in N inputs (atmospheric deposition, imported food and agricultural fertilizers), outputs (N concentration and export) and retention in the urbanizing Lamprey River watershed in coastal NH. Overall, the Lamprey watershed is 70% forested, receives about 13.5 kg N/ha/yr and has a high rate of annual N retention (85%). Atmospheric deposition (8.7 kg/ha/yr) is the largest N input to the watershed. Of the 2.2 kg N/ha/yr exported in the Lamprey River, dissolved organic N (DON) is the dominant form (50% of total) and it varies spatially throughout the watershed with wetland cover. Nitrate accounts for 30% of the N exported, shows a statistically significant increase from 1999 to 2009, and its spatial variability in both concentration and export is related to human population density. In sub-basins throughout the Lamprey, inorganic N retention is high (85-99%), but the efficiency of N retention declines sharply with increased human population density and associated anthropogenic N inputs. N assimilation in the vegetation, denitrification to the atmosphere and storage in the groundwater pool could all be important contributors to the current high rates of N retention. The temporal and spatial patterns that we have observed in nitrate concentration and export are driven by increases in N inputs and impervious surfaces over time, but the declining efficiency of N retention suggests that the watershed may also be reaching N saturation. The downstream receiving estuary, Great Bay, already suffers from low dissolved oxygen levels and eelgrass loss in part due to N loading from the Lamprey watershed. Targeting and reducing

  20. Retention of children under 18 months testing HIV positive in care in ...

    African Journals Online (AJOL)

    Retention of children under 18 months testing HIV positive in care in Swaziland: a retrospective study. ... children within the first two months of life and linking them into care. However, as time progresses the retention of children in care declines. Innovative strategies need to be developed to enhance patient retention.

  1. Molten core retention assembly

    International Nuclear Information System (INIS)

    Lampe, R.F.

    1976-01-01

    Molten fuel produced in a core overheating accident is caught by a molten core retention assembly consisting of a horizontal baffle plate having a plurality of openings therein, heat exchange tubes having flow holes near the top thereof mounted in the openings, and a cylindrical imperforate baffle attached to the plate and surrounding the tubes. The baffle assembly is supported from the core support plate of the reactor by a plurality of hanger rods which are welded to radial beams passing under the baffle plate and intermittently welded thereto. Preferably the upper end of the cylindrical baffle terminates in an outwardly facing lip to which are welded a plurality of bearings having slots therein adapted to accept the hanger rods

  2. Postgraduation retention of medical students from Otago and Auckland medical programmes.

    Science.gov (United States)

    Shelker, William; Poole, Phillippa; Bagg, Warwick; Wood, Ian; Glue, Paul

    2014-01-24

    Auckland and Otago medical programmes have different methods for selecting students. This study compared postgraduate retention in New Zealand (NZ) of medical graduates from the two medical programmes, to assess whether different selection methods influenced retention. Other variables assessed included entrance category and age at graduation. Anonymised databases were created of all graduates from the Otago Faculty of Medicine (1999-2011) and the Auckland medical programme (2000-2012). Demographic and entry category data were recorded. Retention was defined as presence on the NZ Medical Register in December 2012. Risk differences (RD) were calculated to compare retention between the two medical programmes using the Mantel-Haenszel method. The influence of medical programme entrance category on retention was also tested. The influence of covariates on retaining graduates on the register was evaluated using a multiple logistic regression model. The postgraduate retention of graduates of the two medical programmes over 13 years was identical (Auckland 74.9%, Otago 73.6%, P=0.48). Retention of graduate and non-graduate entry students from both medical programmes was similar by 6 years after graduation. Age during medical school did not affect retention. University of attendance had no effect on postgraduation retention of students on the NZ Medical Register, suggesting that retention is not influenced by the different student selection methods at each programme. The data presented shows that New Zealand graduates regardless of programme completed show a similar profile in terms of retention.

  3. Effects of the reduction of the hydraulic retention time to 1.5 days at constant organic loading in CSTR, ASBR, and fixed-bed reactors – Performance and methanogenic community composition

    International Nuclear Information System (INIS)

    Schmidt, Thomas; Ziganshin, Ayrat M.; Nikolausz, Marcell; Scholwin, Frank; Nelles, Michael; Kleinsteuber, Sabine; Pröter, Jürgen

    2014-01-01

    The hydraulic retention time (HRT) is one of the key parameters in biogas processes and often it is postulated that a minimum HRT of 10–25 days is obligatory in continuous stirred tank reactors (CSTR) to prevent a washout of slow growing methanogens. In this study the effects of the reduction of the HRT from 6 to 1.5 days on performance and methanogenic community composition in different systems with and without immobilization operated with simulated thin stillage (STS) at mesophilic conditions and constant organic loading rates (OLR) of 10 g L −1 d −1 of volatile solids were investigated. With the reduction of the HRT process instability was first observed in the anaerobic sequencing batch reactor (ASBR) (at HRT of 3 days) followed by the CSTR (at HRT of 2 days). The fixed bed reactor (FBR) was stable until the end of the experiment, but the reduction of the HRT to 1.5 days caused a decrease of the specific biogas production to about 450 L kg −1 of VS compared to about 600 L kg −1 of VS at HRTs of 4–5 days. Methanoculleus and Methanosarcina were the dominant genera under stable process conditions in the CSTR and the ASBR and members of Methanosaeta and Methanospirillum were only present at HRT of 4 days and lower. In the effluent of the FBR Methanosarcina spp. were not detected and Methanosaeta spp. were more abundant then in the other reactors. - Highlights: • A CSTR was operated at high OLR of 10 (g L −1  d −1  VS) and low HRT of 3 days. • Exceeding washout of methanogenic archaea did not take place. • pH and nutrient concentrations influenced the reproduction rate more than HRT. • Methanoculleus and Methanosarcina were the dominant genera in the CSTR

  4. Promoting Special Educator Teacher Retention

    OpenAIRE

    Jeremy E. Vittek

    2015-01-01

    This article is a critical review of the literature on special education teacher attrition and retention. The research focused on journal articles from 2004 to present. The results of the study helped define special educator attrition and retention. The major themes present in the findings were job satisfaction, administrative support, induction programs, and mentoring. The literature shows a clear need for comprehensi...

  5. [Systematic evaluation of retention behavior of carbohydrates in hydrophilic interaction liquid chromatography].

    Science.gov (United States)

    Fu, Qing; Wang, Jun; Liang, Tu; Xu, Xiaoyong; Jin, Yu

    2013-11-01

    A systematic evaluation of retention behavior of carbohydrates in hydrophilic interaction liquid chromatography (HILIC) was performed. The influences of mobile phase, stationary phase and buffer salt on the retention of carbohydrates were investigated. According to the results, the retention time of carbohydrates decreased as the proportion of acetonitrile in mobile phase decreased. Increased time of carbohydrates was observed as the concentration of buffer salt in mobile phase increased. The retention behavior of carbohydrates was also affected by organic solvent and HILIC stationary phase. Furthermore, an appropriate retention equation was used in HILIC mode. The retention equation lnk = a + blnC(B) + cC(B) could quantitatively describe the retention factors of carbohydrates of plant origin with good accuracy: the relative error of the predicted time to actual time was less than 0.3%. The evaluation results could provide guidance for carbohydrates to optimize the experimental conditions in HILIC method development especially for carbohydrate separation

  6. Domain similarity based orthology detection.

    Science.gov (United States)

    Bitard-Feildel, Tristan; Kemena, Carsten; Greenwood, Jenny M; Bornberg-Bauer, Erich

    2015-05-13

    Orthologous protein detection software mostly uses pairwise comparisons of amino-acid sequences to assert whether two proteins are orthologous or not. Accordingly, when the number of sequences for comparison increases, the number of comparisons to compute grows in a quadratic order. A current challenge of bioinformatic research, especially when taking into account the increasing number of sequenced organisms available, is to make this ever-growing number of comparisons computationally feasible in a reasonable amount of time. We propose to speed up the detection of orthologous proteins by using strings of domains to characterize the proteins. We present two new protein similarity measures, a cosine and a maximal weight matching score based on domain content similarity, and new software, named porthoDom. The qualities of the cosine and the maximal weight matching similarity measures are compared against curated datasets. The measures show that domain content similarities are able to correctly group proteins into their families. Accordingly, the cosine similarity measure is used inside porthoDom, the wrapper developed for proteinortho. porthoDom makes use of domain content similarity measures to group proteins together before searching for orthologs. By using domains instead of amino acid sequences, the reduction of the search space decreases the computational complexity of an all-against-all sequence comparison. We demonstrate that representing and comparing proteins as strings of discrete domains, i.e. as a concatenation of their unique identifiers, allows a drastic simplification of search space. porthoDom has the advantage of speeding up orthology detection while maintaining a degree of accuracy similar to proteinortho. The implementation of porthoDom is released using python and C++ languages and is available under the GNU GPL licence 3 at http://www.bornberglab.org/pages/porthoda .

  7. Retention of Root Canal Posts

    DEFF Research Database (Denmark)

    Sahafi, A; Benetti, Ana Raquel; Flury, S

    2015-01-01

    The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc...... received tribochemical silicate coating according to the manufacturer's instructions. Posts were then luted in the prepared root canals (n=30 per group). Following water storage at 37°C for seven days, retention of the posts was determined by the pull-out method. Irrespective of the luting cement......, pretreatment with tribochemical silicate coating significantly increased retention of the posts. Increased cement film thickness resulted in decreased retention of untreated posts and of pretreated posts luted with zinc phosphate cement. Increased cement film thickness had no influence on retention...

  8. Military Retention. A Comparative Outlook

    Directory of Open Access Journals (Sweden)

    Vasile Sminchise

    2016-06-01

    Full Text Available One of the main goals for human resources management structures and for armed forces leaders is to maintain all necessary personnel, both qualitatively and quantitatively for operational needs or for full required capabilities. The retention of military personnel is essential to keep morale and unit readiness and to reduce the costs for recruiting, training, replacement of manpower. Retention rates depend not only on money or other social measures. The goal for retention is to keep in use the most valuable resource that belongs to an organization: the human beings and their knowledge. The aim pf this paper is to provide a comparative analysis of retention measures in various countries based on Research and Technology Organisation report released in 2007 and, thus, provide more examples of retention measures as far as the Romanian military system is concerned.

  9. Influence of Influent Concentration and Hydraulic Retention Time on Purification Effect of Three Floating Plants%进水浓度和水力停留时间对浮水植物净化效果的影响

    Institute of Scientific and Technical Information of China (English)

    王小娟; 陈年来; 褚润

    2016-01-01

    以浮萍、大薸、凤眼莲3种浮水植物为试材,分别在水力停留2d、4d、8d、10d、12d和14d测定污水中DO、COD、TP、NH3-N含量。通过比较植物在不同浓度污水中的净化效果,确定其在最佳浓度污水中对各污染物处理的最佳停留时间。结果表明,3种植物在适宜污水浓度均表现出较强净化效果。净化周期内,NH3-N、TP去除率变化趋势与DO变化趋势一致,大薸、浮萍、凤眼莲在低浓度污水中对NH3-N、TP去除率最好,NH3-N最佳停留时间分别为8 d、12 d、14 d, TP去除的最佳停留时间均为10 d,中浓度污水适合COD去除,大薸、浮萍、凤眼莲对COD去除的最佳停留时间分别为14 d、8 d、10 d。%Taking three floating plants Pistia stratiotes L., Lemna minor L.and Eichhornia crassipes ( Mart.) Solme as test materials , the concentration of DO , COD, TP, NH3 -N in sewage were determined by setting hydraulic residence time as 2 d, 4 d, 8 d, 10 d, 12 d and 14 d, respectively.Comparing the plant purification effect in different concentration sewage , the optimal hydraulic retention time ( HRT) of plants in the optimal sewage concentration was determined , Results showed that these three floating plants had strong purifying effect on appropriate concentration sewage .During the purification cycle , Pistia stratiotes L., Lemna minor L. and Eichhornia crassipes ( Mart.) Solme had the best removal rate of NH 3 -N and TP in low concentration .The optimal HRT of NH3 -N removal were 8 d, 12 d and 14 d, respectively.The best HRT of TP removal were all 10 d.Medium concentration sewage was appropriate for COD removal .The optimal residence time of Pistia stratiotes L., Lemna minor L., and Eichhournia crassipes ( Mart.) Slome on COD removal were 14 d, 8 d and 10 d, respectively .

  10. Nicotine delivery, retention and pharmacokinetics from various electronic cigarettes.

    Science.gov (United States)

    St Helen, Gideon; Havel, Christopher; Dempsey, Delia A; Jacob, Peyton; Benowitz, Neal L

    2016-03-01

    To measure the systemic retention of nicotine, propylene glycol (PG) and vegetable glycerin (VG) in electronic cigarette (e-cigarette) users, and assess the abuse liability of e-cigarettes by characterizing nicotine pharmacokinetics. E-cigarette users recruited over the internet participated in a 1-day research ward study. Subjects took 15 puffs from their usual brand of e-cigarette. Exhaled breath was trapped in gas-washing bottles and blood was sampled before and several times after use. San Francisco, California, USA. Thirteen healthy, experienced adult e-cigarette users (six females and seven males). Plasma nicotine was analyzed by gas chromatography-mass spectrometry (GC-MS/MS) and nicotine, VG and PG in e-liquids and gas traps were analyzed by LC-MS/MS. Heart rate changes and subjective effects were assessed. E-cigarettes delivered an average of 1.33 (0.87-1.79) mg [mean and 95% confidence interval (CI)] of nicotine, and 93.8% of the inhaled dose, 1.22 (0.80-1.66) was systemically retained. Average maximum plasma nicotine concentration (Cmax ) was 8.4 (5.4-11.5) ng/ml and time of maximal concentration (Tmax ) was 2-5 minutes. One participant had Tmax of 30 minutes. 84.4% and 91.7% of VG and PG, respectively, was systemically retained. Heart rate increased by an average of 8.0 beats per minute after 5 minutes. Withdrawal and urge to smoke decreased and the e-cigarettes were described as satisfying. E-cigarettes can deliver levels of nicotine that are comparable to or higher than typical tobacco cigarettes, with similar systemic retention. Although the average maximum plasma nicotine concentration in experienced e-cigarette users appears to be generally lower than what has been reported from tobacco cigarette use, the shape of the pharmacokinetic curve is similar, suggesting addictive potential. © 2015 Society for the Study of Addiction.

  11. Similar or different?

    DEFF Research Database (Denmark)

    Cornér, Solveig; Pyhältö, Kirsi; Peltonen, Jouni

    2018-01-01

    Previous research has identified researcher community and supervisory support as key determinants of the doctoral journey contributing to students’ persistence and robustness. However, we still know little about cross-cultural variation in the researcher community and supervisory support experien...... counter partners, whereas the Finnish students perceived lower levels of instrumental support than the Danish students. The findings imply that seemingly similar contexts hold valid differences in experienced social support and educational strategies at the PhD level....... experienced by PhD students within the same discipline. This study explores the support experiences of 381 PhD students within the humanities and social sciences from three research-intensive universities in Denmark (n=145) and Finland (n=236). The mixed methods design was utilized. The data were collected...... counter partners. The results also indicated that the only form of support in which the students expressed more matched support than mismatched support was informational support. Further investigation showed that the Danish students reported a high level of mismatch in emotional support than their Finnish...

  12. Urinary Retention Associated with Stroke.

    Science.gov (United States)

    Umemura, Takeru; Ohta, Hirotsugu; Yokota, Akira; Yarimizu, Shiroh; Nishizawa, Shigeru

    Patients often exhibit urinary retention following a stroke. Various neuropathological and animal studies have implicated the medulla oblongata, pons, limbic system, frontal lobe as areas responsible for micturition control, although the exact area responsible for urinary retention after stroke is not clear. The purpose of this study was to identify the stroke area responsible for urinary retention by localizing the areas where strokes occur. We assessed 110 patients with cerebral infarction and 27 patients with cerebral hemorrhage (78 men, 59 women; mean age, 73.0 years) who had been admitted to our hospital between October, 2012 and September, 2013. We used computed tomography (CT) and magnetic resonance imaging (MRI) to investigate the stroke location, and evaluated whether post-stroke urinary retention occurred. Twelve (8.8%) of the 137 patients (7 men, 5 women; mean age, 78.8 years) exhibited urinary retention after a stroke. Stroke occurred in the right/left dominant hemisphere in 7 patients; nondominant hemisphere in 1; cerebellum in 3; and brainstem in 1. Strokes in the dominant hemisphere were associated with urinary retention (P = 0.0314), particularly in the area of the insula (P < 0.01). We concluded that stroke affecting the insula of the dominant hemisphere tends to cause urinary retention.

  13. Job embeddedness and nurse retention.

    Science.gov (United States)

    Reitz, O Ed; Anderson, Mary Ann; Hill, Pamela D

    2010-01-01

    Nurse retention is a different way of conceptualizing the employer-employee relationship when compared with turnover. Job embeddedness (JE), a construct based on retention, represents the sum of reasons why employees remain at their jobs. However, JE has not been investigated in relation to locale (urban or rural) or exclusively with a sample of registered nurses (RNs). The purpose of this study was to determine what factors (JE, age, gender, locale, and income) help predict nurse retention. A cross-sectional mailed survey design was used with RNs in different locales (urban or rural). Job embeddedness was measured by the score on the composite, standardized instrument. Nurse retention was measured by self-report items concerning intent to stay. A response rate of 49.3% was obtained. The typical respondent was female (96.1%), white, non-Hispanic (87.4%), and married (74.9%). Age and JE were predictive of nurse retention and accounted for 26% of the explained variance in intent to stay. Although age was a significant predictor of intent to stay, it accounted for only 1.4% of the variance while JE accounted for 24.6% of the variance of nurse retention (as measured by intent to stay). Older, more "embedded" nurses are more likely to remain employed in their current organization. Based on these findings, JE may form the basis for the development of an effective nurse retention program.

  14. The Retention of Female Unrestricted Line Officers

    National Research Council Canada - National Science Library

    Pecenco, Elena G

    2005-01-01

    This thesis analyzes the retention of female Naval officers, focusing on the relationship between officer selection metrics and retention beyond minimum service obligation and the effect of lateral...

  15. Data Retention and Anonymity Services

    Science.gov (United States)

    Berthold, Stefan; Böhme, Rainer; Köpsell, Stefan

    The recently introduced legislation on data retention to aid prosecuting cyber-related crime in Europe also affects the achievable security of systems for anonymous communication on the Internet. We argue that data retention requires a review of existing security evaluations against a new class of realistic adversary models. In particular, we present theoretical results and first empirical evidence for intersection attacks by law enforcement authorities. The reference architecture for our study is the anonymity service AN.ON, from which we also collect empirical data. Our adversary model reflects an interpretation of the current implementation of the EC Directive on Data Retention in Germany.

  16. Modeling of similar economies

    Directory of Open Access Journals (Sweden)

    Sergey B. Kuznetsov

    2017-06-01

    Full Text Available Objective to obtain dimensionless criteria ndash economic indices characterizing the national economy and not depending on its size. Methods mathematical modeling theory of dimensions processing statistical data. Results basing on differential equations describing the national economy with the account of economical environment resistance two dimensionless criteria are obtained which allow to compare economies regardless of their sizes. With the theory of dimensions we show that the obtained indices are not accidental. We demonstrate the implementation of the obtained dimensionless criteria for the analysis of behavior of certain countriesrsquo economies. Scientific novelty the dimensionless criteria are obtained ndash economic indices which allow to compare economies regardless of their sizes and to analyze the dynamic changes in the economies with time. nbsp Practical significance the obtained results can be used for dynamic and comparative analysis of different countriesrsquo economies regardless of their sizes.

  17. Localization of plutonium retention in the small intestine of the neonatal rat, guinea pig, baboon and macaca after Pu-citrate ingestion

    International Nuclear Information System (INIS)

    Fritsch, P.; Lataillade, G.; Beauvallet, M.; L'Hullier, I.; Lepage, M.; Metivier, H.; Masse, R.; Moutairou, K.; avi, 526, Republique Populaire du Benin)

    1988-01-01

    The retention of Pu-citrate in the gastrointestinal wall was compared at similar post ingestion times after ingestion at 2 days of age by rats and guinea pigs and at 1 to 34 days by neonatal primates. The small intestine was the main site of the Pu retention in all species. In rats and primates, most of the Pu was retained in the distal ileum, whereas in guinea pigs it was more homogeneously distributed. In the rats, Pu was retained in the epithelial cells on villi, but in the guinea pigs and primates it was confined to the macrophages under the epithelial cells in the lacteal region. (author)

  18. A low-volume polyethylene glycol solution was associated with an increased suboptimal bowel preparation rate but had similar recommendations for an early repeat colonoscopy, procedure times, and adenoma detection rates.

    Directory of Open Access Journals (Sweden)

    Sam C Hankins

    Full Text Available Low-volume polyethylene glycol (PEG bowel preparations are better tolerated by patients than high-volume preparations and may achieve similar preparation quality. However, there is little data comparing their effects on a recommendation for an early repeat colonoscopy (because of a suboptimal preparation, procedure times, adenoma detection rate (ADR, and advanced adenoma detection rate (AADR.This is a retrospective cohort study of outpatient colonoscopies performed during a one-year period at a single academic medical center in which low-volume MoviPrep® (n = 1841 or high-volume Colyte® (n = 1337 was used. All preparations were split-dosed. Appropriate covariates were included in regression models assessing suboptimal preparation quality (fair, poor, or inadequate, procedure times, recommendation for an early repeat colonoscopy, ADR, and AADR.MoviPrep® was associated with an increase in having a suboptimal bowel preparation (OR 1.36; 95% CI: 1.06-1.76, but it was not associated with differences in insertion (p = 0.43, withdrawal (p = 0.22, or total procedure times (p = 0.10. The adjusted percentage with a suboptimal preparation was 11.7% for patients using MoviPrep® and 8.8% for patients using Colyte®. MoviPrep® was not associated with a significant difference in overall ADR (OR 0.93; 95% CI: 0.78-1.11, AADR (OR 1.18; 95% CI: 0.87-1.62, or recommendation for early repeat colonoscopy (OR 1.16; 95% CI: 0.72-1.88.MoviPrep® was associated with a small absolute increase in having a suboptimal preparation, but did not affect recommendations for an early repeat colonoscopy, procedure times, or adenoma detection rates. Mechanisms to reduce financial barriers limiting low-volume preparations should be considered because of their favorable tolerability profile.

  19. Farklı Hidrolik Bekletme Sürelerinin Anaerobik Perdeli Reaktörde Sülfat İndirgenmesi Üzerine Etkisi / Effect of Different Hydraulic Retention Time (HRT on Sulfate Reduction in Anaerobic Baffled Reactor

    Directory of Open Access Journals (Sweden)

    Şebnem ÖZDEMİR

    2012-12-01

    üresinin 2 gün olduğu çalışma koşullarında çıkış suyundaki KOİ ve SO4-2 verimleri %84 ile %88 olarak gözlemlenirken bekleme süresinin 0,5 gün olduğu çalışma koşullarında ise bu değer %80 ve %75 olarak gözlemlenmiştir. Ayrıca bekleme süresinin 2 gün olduğu çalışma koşullarında son bölmedeki sülfür oluşum verimi % 75 iken, bekleme süresi 0,5 güne indirildiğinde aynı bölmedeki sülfür oluşum veriminin %96’a çıktığı gözlemlenmiştir. Çıkarımlar ve Özgün Değer: Yapılan bu çalışma ile yüksek sülfat konsantrasyona sahip atıksuların arıtımında anaerobik perdeli reaktörün iyi bir alternatif olabileceği kanıtlanmıştır. Ayrıca çıkış sülfat ve sülfür konsantrasyonlarının değişen HBS’den etkilenmediği gözlenmiştir. Effect of Different Hydraulic Retention Time (HRT on Sulfate Reduction in Anaerobic Baffled Reactor Design and Method: The anaerobic baffled reactor (ABR is a modification of up-flow anaerobic sludge blanket (UASB reactor. A laboratory scale ABR was inoculated with an effluent of a full scale anaerobic digester located in Kayseri Wastewater Treatment Plant, Turkey. Before inoculation, the sludge was sieved to remove coarse materials. The ABR was 20 cm wide, 80 cm long, 20 cm deep and constructed from glass, with a working volume of 19 L. Reactor was divided into four equal 4.75 L compartments by vertical baffles, each compartment having down-comer and riser regions created by further vertical baffle. The lower parts of down-comer baffles were angled at 450 in order to direct the flow evenly through the riser. Ethanol and sulfate are consumed as electron donor and electron acceptor, respectively. Sulfate, dissolved sulfide, pH, alkalinity and chemical oxygen demand (COD have measured three times a week. Aim: There are varying structures and concentrations of sulfate compounds in natural waters. In addition, the amount of sulfate is higher in some industrial wastewaters In addition, some

  20. POSSIBLE RECESSION CURVE APPLICATIONS FOR RETENTION EVALUATION

    Directory of Open Access Journals (Sweden)

    Daniel Liberacki

    2015-11-01

    Full Text Available The objective of the article was to present possible applications of recession flow curve in a small lowland watershed retention discharge size evaluation. The examined woodland micro catchment area of 0.52 sq km is located in Puszcza Zielonka in central Wielkopolska. The Hutka catchment is typically woody with high retention abilities. The catchment of the Hutka watercourse is forested in 89%, the other 11% is covered by swamps and wasteland. The predominant sites are fresh mixed coniferous forest (BMśw, fresh coniferous forest (Bśw and alder carr forest (Ol. Landscape in catchment is characterized by a large number of interior depressions, filled partly with rainwater or peatbogs, with poorly developed natural drainage. The watercourses do not exceed 1 km in length, the mean width is approx. 0.5 m, while mean depth ranges from 0.2 to 0.3 m. During hydrological research conducted in 1997/1998–1999/2000, 35 major (characteristic raised water stages were observed in Hutka after substantial precipitation. The recession curve dating from 18–24 September 2000 has the α and n rates nearest to average. Comparing the model curve and the curve created by observing watercourse flow, one can notice their resemblance and that they have similar ordinate values as well as shape. In the case of other recession curves, the maximum differences of ordinate values are also about 0.1–0.2 l/s/km2. The measuured α and n rates do not reveal any regularities. There are no significant statistical Horton model parameter (for recession flow curves dependencies between α and n and e.g. initial flows (Qo or the whole period of high water waves (Qp. Consequently, calculated relation between these parameters is only an approximation for the general evaluation of the retention discharge in the catchment area towards retention with flow function.

  1. A modelling study of long term green roof retention performance.

    Science.gov (United States)

    Stovin, Virginia; Poë, Simon; Berretta, Christian

    2013-12-15

    This paper outlines the development of a conceptual hydrological flux model for the long term continuous simulation of runoff and drought risk for green roof systems. A green roof's retention capacity depends upon its physical configuration, but it is also strongly influenced by local climatic controls, including the rainfall characteristics and the restoration of retention capacity associated with evapotranspiration during dry weather periods. The model includes a function that links evapotranspiration rates to substrate moisture content, and is validated against observed runoff data. The model's application to typical extensive green roof configurations is demonstrated with reference to four UK locations characterised by contrasting climatic regimes, using 30-year rainfall time-series inputs at hourly simulation time steps. It is shown that retention performance is dependent upon local climatic conditions. Volumetric retention ranges from 0.19 (cool, wet climate) to 0.59 (warm, dry climate). Per event retention is also considered, and it is demonstrated that retention performance decreases significantly when high return period events are considered in isolation. For example, in Sheffield the median per-event retention is 1.00 (many small events), but the median retention for events exceeding a 1 in 1 yr return period threshold is only 0.10. The simulation tool also provides useful information about the likelihood of drought periods, for which irrigation may be required. A sensitivity study suggests that green roofs with reduced moisture-holding capacity and/or low evapotranspiration rates will tend to offer reduced levels of retention, whilst high moisture-holding capacity and low evapotranspiration rates offer the strongest drought resistance. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Increasing Army Retention Through Incentives

    National Research Council Canada - National Science Library

    Beerman, Kevin

    2006-01-01

    .... If the Army fails to address the enlisted retention issue in the near future departures of experienced NCOs will have a detrimental impact our military's ability to provide for our nation's security...

  3. Is Enlisted Retention too High?

    National Research Council Canada - National Science Library

    Hansen, M

    2003-01-01

    .... The consensus appears to be that higher retention is better for the Navy; more experienced Sailors improve readiness and allow the Navy to devote fewer resources to the recruiting, training, and acculturation of new accessions...

  4. phosphorus retention data and metadata

    Science.gov (United States)

    phosphorus retention in wetlands data and metadataThis dataset is associated with the following publication:Lane , C., and B. Autrey. Phosphorus retention of forested and emergent marsh depressional wetlands in differing land uses in Florida, USA. Wetlands Ecology and Management. Springer Science and Business Media B.V;Formerly Kluwer Academic Publishers B.V., GERMANY, 24(1): 45-60, (2016).

  5. Promoting Special Educator Teacher Retention

    Directory of Open Access Journals (Sweden)

    Jeremy E. Vittek

    2015-06-01

    Full Text Available This article is a critical review of the literature on special education teacher attrition and retention. The research focused on journal articles from 2004 to present. The results of the study helped define special educator attrition and retention. The major themes present in the findings were job satisfaction, administrative support, induction programs, and mentoring. The literature shows a clear need for comprehensive administrative support to improve job satisfaction and the likelihood a special educator will remain in their job.

  6. Retention and Healing Outcomes after Intentional Replantation.

    Science.gov (United States)

    Cho, Sin-Yeon; Lee, Yoon; Shin, Su-Jung; Kim, Euiseong; Jung, Il-Young; Friedman, Shimon; Lee, Seung-Jong

    2016-06-01

    Intentional replantation is an alternative to tooth extraction and prosthetic replacement when conventional endodontic treatment modalities are unfeasible or contraindicated. This study assessed tooth retention and healing after intentional replantation and explored predictors of these outcomes. Data of intentional replantation procedures performed between March 2000 and December 2010 were collected prospectively, excluding teeth with preoperative periodontal and root defects. A cohort of 159 teeth was followed up for 0.5-12 years. Retention and healed status without complications (periapical radiolucency, external root resorption, ankylosis, signs/symptoms, probing ≥6 mm) was recorded and analyzed with Kaplan-Meier survival analysis and Cox proportional hazard regression model (P regression identified extraoral time ≤15 minutes as predictor of complication-free healing (P < .04; hazard ratio, 2.767; 95% confidence interval, 1.053-7.272). This prospective cohort study of contemporary intentional replantation suggested a cumulative 12-year retention rate of 93% and healed rate of 77% after 3 years. Healing occurred 1.7 times more frequently in teeth replanted within 15 minutes. Although most complications occurred within 1 year after replantation, follow-up should extend for at least 3 years to capture late complications. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. Determination of water retention curves of concrete

    International Nuclear Information System (INIS)

    Villar, M.V.; Romero, F.J.

    2015-01-01

    The water retention curves of concrete and mortar obtained with two different techniques and following wetting and drying paths were determined. The material was the same used to manufacture the disposal cells of the Spanish surface facility of El Cabril. The water retention capacity of mortar is clearly higher than that of concrete when expressed as gravimetric water content, but the difference reduces when it is expressed as degree of saturation. Hysteresis between wetting and drying was observed for both materials, particularly for mortar. The tests went on for very long periods of time, and concerns about the geochemical, mineralogical and porosity changes occurred in the materials during the determinations (changes in dry mass, grain density, samples volume) and their repercussion on the results obtained (water content and degree of saturation computation) were raised. Also, the fact of having used techniques applying total and matrix suction could have affected the results. (authors)

  8. Motivational Factors of Employee Retention and Engagement in Organizations

    OpenAIRE

    Benjamin Balbuena Aguenza; Ahmad Puad Mat Som

    2012-01-01

    Retention is the process of physically keeping employee members in an organization as it is one of the key fundamentals that are necessary for organizational success. In a globalized environment, retention and engagement of high prospective employees are a huge challenge to organizations especially in times of high turnover rates. In many cases, even engaged employees are sometimes dissatisfied with the outcomes of organizational performance which may lead them to look elsewhere. ...

  9. Sexual dimorphism in stature (SDS), jealousy and mate retention.

    Science.gov (United States)

    Brewer, Gayle; Riley, Charlene

    2010-10-02

    Previous research has investigated the manner in which absolute height impacts on jealousy and mate retention. Although relative height is also important, little information exists about the potential influence of sexual dimorphism in stature (SDS) within established relationships. The current study investigated the relationship between SDS and the satisfaction, jealousy and mate retention behaviors reported by men and women. Heterosexual men (n = 98) and women (n = 102) completed a questionnaire. Men in high SDS relationships reported the lowest levels of cognitive and behavioral jealousy, although the impact of SDS on relationship satisfaction was less clear. SDS was not associated with the overall use of mate retention strategies; SDS did however affect the use of three specific strategies (vigilance, monopolization of time, love and care). SDS did not affect women's relationship satisfaction, jealousy (cognitive, behavioral, or emotional) or the use of mate retention strategies (with the exception of resource display).

  10. Retrieval practice in the form of online homework improved information retention more when spaced 5 days rather than 1 day after class in two physiology courses.

    Science.gov (United States)

    Cadaret, Caitlin N; Yates, Dustin T

    2018-06-01

    Studies have shown that practicing temporally spaced retrieval of previously learned information via formal assessments increases student retention of the information. Our objective was to determine the impact of online homework administered as a first retrieval practice 1 or 5 days after introduction of physiology topics on long-term information retention. Students in two undergraduate courses, Anatomy and Physiology (ASCI 240) and Animal Physiological Systems (ASCI 340), were presented with information on a specific physiological system during each weekly laboratory and then completed an online homework assignment either 1 or 5 days later. Information retention was assessed via an in-class quiz the following week and by a comprehensive final exam at semester's end (4-13 wk later). Performance on homework assignments was generally similar between groups for both courses. Information retention at 1 wk did not differ due to timing of homework in either course. In both courses, however, students who received homework 5 days after class performed better on final exam questions relevant to that week's topic compared with their day 1 counterparts. These findings indicate that the longer period between introducing physiology information in class and assigning the first retrieval practice was more beneficial to long-term information retention than the shorter period, despite seemingly equivalent benefits in the shorter term. Since information is typically forgotten over time, we speculate that the longer interval necessitates greater retrieval effort in much the same way as built-in desirable difficulties, thus allowing for stronger conceptual connections and deeper comprehension.

  11. Description of the Retention and Peak Profile for Chromolith Columns in Isocratic and Gradient Elution Using Mobile Phase Composition and Flow Rate as Factors

    Directory of Open Access Journals (Sweden)

    Elsa Cabo-Calvet

    2014-11-01

    Full Text Available The effect of the modifier concentration and flow rate on the chromatographic performance of a second generation Chromolith® RP-18e column, under isocratic and gradient elution with acetonitrile-water mixtures, was examined using four sulphonamides as probe compounds. The acetonitrile concentration was varied between 5 and 55% (v/v, and the flow rate between 0.1 and 5.0 mL/min, keeping the other factors constant. The changes in both retention and peak profile were modelled, and used to build simple plots, where the logarithm of the retention factor was represented against the modifier concentration (in gradient elution, against the initial modifier concentration, and the half-widths or widths against the retention time (in gradient elution, against the time at the column outlet. A particular plot was needed for describing the retention of each sulphonamide, but due to the similar interaction kinetics, a unique plot described the changes in the half-widths for all four sulphonamides. The changes in retention with the flow showed that allegedly in the second generation Chromolith, the column deformation observed for the first generation Chromolith, with the applied pressure at increasing flow, is decreased.

  12. RAINWATER RETENTION ON THE HEAVILY INDUSTRIALIZED AREAS

    Directory of Open Access Journals (Sweden)

    Bartosz Kaźmierczak

    2016-06-01

    Full Text Available The paper presents the dimensioning of retention reservoirs indicator method regarding to the German DWA-A 117 guideline, recommended for small rainfall catchments (with an area of 200 ha. A comparative calculation of the retention reservoirs overflow useful volume were conducted for 4 variants of catchment development (degree sealing surface varied from 60% to 90%, under the assumed sewage outflow from the tank at the level of the urban basin natural runoff. At given conditions required unit volume of retention reservoirs, from 145.4 m3 to 206.7 m3 for each 1 ha of catchment area were determined. The obtained results confirmed the fact that useful volume of the tanks were decreased, when Blaszczyk’s pattern reliable rainwater streams were used for calculations. Because the DWA-A 117 guideline method should be applied to a small rainfall catchments, it is recommended to verify the hydraulic capacity of dimensioned channels and objects using hydrodynamic simulations at different load of rainfall catchment scenarios, variable in time and space.

  13. Mobile Learning and Student Retention

    Directory of Open Access Journals (Sweden)

    Bharat Inder Fozdar

    2007-06-01

    Full Text Available Student retention in open and distance learning (ODL is comparatively poor to traditional education and, in some contexts, embarrassingly low. Literature on the subject of student retention in ODL indicates that even when interventions are designed and undertaken to improve student retention, they tend to fall short. Moreover, this area has not been well researched. The main aim of our research, therefore, is to better understand and measure students’ attitudes and perceptions towards the effectiveness of mobile learning. Our hope is to determine how this technology can be optimally used to improve student retention at Bachelor of Science programmes at Indira Gandhi National Open University (IGNOU in India. For our research, we used a survey. Results of this survey clearly indicate that offering mobile learning could be one method improving retention of BSc students, by enhancing their teaching/ learning and improving the efficacy of IGNOU’s existing student support system. The biggest advantage of this technology is that it can be used anywhere, anytime. Moreover, as mobile phone usage in India explodes, it offers IGNOU easy access to a larger number of learners. This study is intended to help inform those who are seeking to adopt mobile learning systems with the aim of improving communication and enriching students’ learning experiences in their ODL institutions.

  14. Flocculation of retention pond water

    International Nuclear Information System (INIS)

    Hart, B.T.; McGregor, R.J.

    1982-05-01

    An integral part of the water management strategy proposed by Ranger Uranium Mining Pty. Ltd. involves the collection of runoff water in a series of retention ponds. This water will subsequently be used in the uranium milling plant or released to Magela Creek. Runoff water collected during the wet season caused a section of Magela Creek to become turbid when it was released. The eroded material causing the turbidity was very highly dispersed and showed little tendency to sediment out in the retention ponds. Results of a preliminary study to determine the feasibility of clarifying retention pond water by flocculation with alum are presented. A concentration of 30 Mg/L alum reduced turbidity from an initial 340 NTU to less than 30 NTU in four hours

  15. Strategies to improve retention in randomised trials

    Science.gov (United States)

    Brueton, Valerie C; Tierney, Jayne; Stenning, Sally; Harding, Seeromanie; Meredith, Sarah; Nazareth, Irwin; Rait, Greta

    2013-01-01

    Background Loss to follow-up from randomised trials can introduce bias and reduce study power, affecting the generalisability, validity and reliability of results. Many strategies are used to reduce loss to follow-up and improve retention but few have been formally evaluated. Objectives To quantify the effect of strategies to improve retention on the proportion of participants retained in randomised trials and to investigate if the effect varied by trial strategy and trial setting. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PreMEDLINE, EMBASE, PsycINFO, DARE, CINAHL, Campbell Collaboration's Social, Psychological, Educational and Criminological Trials Register, and ERIC. We handsearched conference proceedings and publication reference lists for eligible retention trials. We also surveyed all UK Clinical Trials Units to identify further studies. Selection criteria We included eligible retention trials of randomised or quasi-randomised evaluations of strategies to increase retention that were embedded in 'host' randomised trials from all disease areas and healthcare settings. We excluded studies aiming to increase treatment compliance. Data collection and analysis We contacted authors to supplement or confirm data that we had extracted. For retention trials, we recorded data on the method of randomisation, type of strategy evaluated, comparator, primary outcome, planned sample size, numbers randomised and numbers retained. We used risk ratios (RR) to evaluate the effectiveness of the addition of strategies to improve retention. We assessed heterogeneity between trials using the Chi2 and I2 statistics. For main trials that hosted retention trials, we extracted data on disease area, intervention, population, healthcare setting, sequence generation and allocation concealment. Main results We identified 38 eligible retention trials. Included trials evaluated six broad types of strategies to improve retention. These

  16. EFFECTS OF ANISOMYCIN ON RETENTION OF THE PASSIVE-AVOIDANCE HABIT AS A FUNCTION OF AGE

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Hasker P.; Rosenzweig, Mark R.; Kinkade, Patrick T.; Bennett, Edward L.

    1980-09-01

    Three age groups of male Swiss albino CD-1 mice (2-3 mo, 6-7 mo, and 14-15 mo) were treated with a 120 mg/kg dose of the protein synthesis inhibitor anisomycin or with an equal volume of saline at various times before and after training (20 min pretraining, 0, 10, 30, and 180 min posttraining) in a shock motivated passive-avoidance task. Young (2-3 mo) and intermediate-aged (6-7 mo) mice treated with anisomycin before or immediately after training demonstrated impaired retention at a 7 day test, but retention was normal for mice injected 10, 30, or 180 min posttraining. The older mice (14-15 mo) showed similar results, with one exception: Those older mice injected with anisomycin 10 min posttraining were significantly impared in retention as compared to older saline controls and to identically treated young or intermediate-aged mice. The prolonged gradient of retrograde amnesia demonstrated by older mice could not be accounted for by impaired acquisition, impaired short-term memory, altered spontaneous locomotor activity, or differential inhibition of brain protein synthesis.

  17. Seniority bosons from similarity transformations

    International Nuclear Information System (INIS)

    Geyer, H.B.

    1986-01-01

    The requirement of associating in the boson space seniority with twice the number of non-s bosons defines a similarity transformation which re-expresses the Dyson pair boson images in terms of seniority bosons. In particular the fermion S-pair creation operator is mapped onto an operator which, unlike the pair boson image, does not change the number of non-s bosons. The original results of Otsuka, Arima and Iachello are recovered by this procedure while at the same time they are generalized to include g-bosons or even bosons with J>4 as well as any higher order boson terms. Furthermore the seniority boson images are valid for an arbitrary number of d- or g-bosons - a result which is not readily obtainable within the framework of the usual Marumori- or OAI-method

  18. Sleep confers a benefit for retention of statistical language learning in 6.5month old infants.

    Science.gov (United States)

    Simon, Katharine N S; Werchan, Denise; Goldstein, Michael R; Sweeney, Lucia; Bootzin, Richard R; Nadel, Lynn; Gómez, Rebecca L

    2017-04-01

    Infants show robust ability to track transitional probabilities within language and can use this information to extract words from continuous speech. The degree to which infants remember these words across a delay is unknown. Given well-established benefits of sleep on long-term memory retention in adults, we examine whether sleep similarly facilitates memory in 6.5month olds. Infants listened to an artificial language for 7minutes, followed by a period of sleep or wakefulness. After a time-matched delay for sleep and wakefulness dyads, we measured retention using the head-turn-preference procedure. Infants who slept retained memory for the extracted words that was prone to interference during the test. Infants who remained awake showed no retention. Within the nap group, retention correlated with three electrophysiological measures (1) absolute theta across the brain, (2) absolute alpha across the brain, and (3) greater fronto-central slow wave activity (SWA). Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Clinical trials: the challenge of recruitment and retention of participants.

    Science.gov (United States)

    Gul, Raisa B; Ali, Parveen A

    2010-01-01

    conceptual thinking as part of the research design. An understanding of the challenges and issues related to recruitment and retention can help researchers to think ahead about the strategies to overcome these issues and consequently save the time and energy of the participants, researchers and funding agencies.

  20. Safeguards Knowledge Management & Retention at U.S. National Laboratories.

    Energy Technology Data Exchange (ETDEWEB)

    Haddal, Risa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Rebecca [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bersell, Bridget [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Frazar, Sarah [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burbank, Roberta [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stevens, Rebecca [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cain, Ron [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kirk, Bernadette [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Morell, Sean [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    In 2017, four U.S. National Laboratories collaborated on behalf of DOE/NNSA to explore the safeguards knowledge retention problem, identify possible approaches, and develop a strategy to address it. The one-year effort consisted of four primary tasks. First, the project sought to identify critical safeguards information at risk of loss. Second, a survey and workshop were conducted to assess nine U.S. National Laboratories' efforts to determine current safeguards knowledge retention practices and challenges, and identify best practices. Third, specific tools were developed to identify and predict critical safeguards knowledge gaps and how best to recruit in order to fill those gaps. Finally, based on findings from the first three tasks and research on other organizational approaches to address similar issues, a strategy was developed on potential knowledge retention methods, customized HR policies, and best practices that could be implemented across the National Laboratory Complex.

  1. Retention of Esperanto Is Affected by Delay-Interval Task and Item Closure: A Partial Resolution of the Delay-Retention Effect

    Science.gov (United States)

    Brosvic, Gary M.; Epstein, Michael L.; Dihoff, Roberta E.; Cook, Michael L.

    2006-01-01

    The present studies were undertaken to examine the effects of manipulating delay-interval task (Study 1) and timing of feedback (Study 2) on acquisition and retention. Participants completed a 100-item cumulative final examination, which included 50 items from each laboratory examination, plus 50 entirely new items. Acquisition and retention were…

  2. 60Co retention by Mexican montmorillonites

    International Nuclear Information System (INIS)

    Pacheco, G.; Martinez, V.; Bosch, P.; Bulbulian, S.

    1995-01-01

    Radioactive elements may be retained by clays. The ability of natural Mexican clays to retain radioactive Co from aqueous solutions, is discussed. Experiments were performed with solutions containing labeled cobalt. The effect of contact time on Co 2+ retention was studied. It was found that the Co 2+ uptake value in dehydrated montmorillonites is between 0.30 and 0.70 meq g -1 of clay. A sorption sequence was obtained for the various clays. The samples were characterized, before and after cobalt exchange, by X-ray diffraction. (author). 7 refs., 3 figs., 3 tabs

  3. Cyber Workforce Retention

    Science.gov (United States)

    2016-10-01

    analysts, who most closely coincide with members of the 1B4 occupation skill set . However, adjusting for the local labor markets where approximately 80–85...fewer than 10 years. 2. Cyber Airmen, in particular 1B4s, have the skill sets needed in the labor market : their skills are extremely portable and...professionals collides with a world labor market already experi- encing a dramatic deficit in individuals with these skills . At the same time, the United

  4. Modelling of long term nitrogen retention in surface waters

    Science.gov (United States)

    Halbfaß, S.; Gebel, M.; Bürger, S.

    2010-12-01

    In order to derive measures to reduce nutrient loadings into waters in Saxony, we calculated nitrogen inputs with the model STOFFBILANZ on the regional scale. Thereby we have to compare our modelling results to measured loadings at the river basin outlets, considering long term nutrient retention in surface waters. The most important mechanism of nitrogen retention is the denitrification in the contact zone of water and sediment, being controlled by hydraulic and micro-biological processes. Retention capacity is derived on the basis of the nutrient spiralling concept, using water residence time (hydraulic aspect) and time-specific N-uptake by microorganisms (biological aspect). Short time related processes of mobilization and immobilization are neglected, because they are of minor importance for the derivation of measures on the regional scale.

  5. Sodium and chloride exclusion and retention by non-grafted and grafted melon and Cucurbita plants

    Science.gov (United States)

    Edelstein, M.; Plaut, Z.; Ben-Hur, M.

    2011-01-01

    The effects of grafting on Na and Cl– uptake and distribution in plant tissues were quantified in a greenhouse experiment using six combinations of melon (Cucumis melo L. cv. Arava) and pumpkin (Cucurbita maxima Duchesne×Cucurbita moschata Duchesne cv. TZ-148): non-grafted, self-grafted, melons grafted on pumpkins, and pumpkins grafted on melons. Total Na concentration in shoots of plants with pumpkin or melon rootstocks was 400 mmol kg−1, respectively, regardless of the scion. In contrast, shoot Cl– concentrations were quite similar among the different scion–rootstock combinations. Na concentrations in exudates from cut stems of plants with a pumpkin rootstock were very low (<0.18 mM), whereas those in the exudates of plants with melon rootstocks ranged from 4.7 mM to 6.2 mM, and were quite similar to the Na concentration in the irrigation water. Root Na concentrations averaged 11.7 times those in the shoots of plants with pumpkin rootstocks, while in plants with melon rootstocks, values were similar. Two mechanisms could explain the decrease in shoot Na concentrations in plants with pumpkin rootstocks: (i) Na exclusion by the pumpkin roots; and (ii) Na retention and accumulation within the pumpkin rootstock. Quantitative analysis indicated that the pumpkin roots excluded ∼74% of available Na, while there was nearly no Na exclusion by melon roots. Na retention by the pumpkin rootstocks decreased its amount in the shoot by an average 46.9% compared with uniform Na distribution throughout the plant. In contrast, no retention of Na could be found in plants grafted on melons. PMID:20729482

  6. Sodium and chloride exclusion and retention by non-grafted and grafted melon and Cucurbita plants.

    Science.gov (United States)

    Edelstein, M; Plaut, Z; Ben-Hur, M

    2011-01-01

    The effects of grafting on Na and Cl(-) uptake and distribution in plant tissues were quantified in a greenhouse experiment using six combinations of melon (Cucumis melo L. cv. Arava) and pumpkin (Cucurbita maxima Duchesne×Cucurbita moschata Duchesne cv. TZ-148): non-grafted, self-grafted, melons grafted on pumpkins, and pumpkins grafted on melons. Total Na concentration in shoots of plants with pumpkin or melon rootstocks was 400 mmol kg(-1), respectively, regardless of the scion. In contrast, shoot Cl(-) concentrations were quite similar among the different scion-rootstock combinations. Na concentrations in exudates from cut stems of plants with a pumpkin rootstock were very low (<0.18 mM), whereas those in the exudates of plants with melon rootstocks ranged from 4.7 mM to 6.2 mM, and were quite similar to the Na concentration in the irrigation water. Root Na concentrations averaged 11.7 times those in the shoots of plants with pumpkin rootstocks, while in plants with melon rootstocks, values were similar. Two mechanisms could explain the decrease in shoot Na concentrations in plants with pumpkin rootstocks: (i) Na exclusion by the pumpkin roots; and (ii) Na retention and accumulation within the pumpkin rootstock. Quantitative analysis indicated that the pumpkin roots excluded ∼74% of available Na, while there was nearly no Na exclusion by melon roots. Na retention by the pumpkin rootstocks decreased its amount in the shoot by an average 46.9% compared with uniform Na distribution throughout the plant. In contrast, no retention of Na could be found in plants grafted on melons.

  7. 31 CFR 103.38 - Nature of records and retention period.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Nature of records and retention... § 103.38 Nature of records and retention period. (a) Wherever it is required that there be retained... reasonable period of time, taking into consideration the nature of the record, and the amount of time expired...

  8. Retention-Oriented Curricular Design

    Science.gov (United States)

    Milanovic, Ivana; Eppes, Tom A.; Girouard, Janice; Townsend, Lee

    2010-01-01

    This paper presents a retention-oriented approach to the educational value stream within the STEM undergraduate area. Faced with several strategic challenges and opportunities, a Flex Advantage Plan was developed to enhance the undergraduate engineering technology programs and better utilize the curricular flexibilities inherent in the current…

  9. Memory control with selective retention

    NARCIS (Netherlands)

    2012-01-01

    The present invention relates to a memory circuit and a method of controlling data retention in the memory circuit, wherein a supply signal is selectively switched to a respective one of at least two virtual supply lines (24) each shared by a respective one of a plurality of groups (30-1 to 30-n) of

  10. Memory control with selective retention

    NARCIS (Netherlands)

    2010-01-01

    The present invention relates to a memory circuit and a method of controlling data retention in the memory circuit, wherein a supply signal is selectively switched to a respective one of at least two virtual supply lines (24) each shared by a respective one of a plurality of groups (30-1 to 30-n) of

  11. Maslow's Hierarchy and Student Retention.

    Science.gov (United States)

    Brookman, David M.

    1989-01-01

    Abraham Maslow's hierarchy of needs offers perspective on student motivation and a rationale for college retention programing. Student affairs and faculty interventions addressing student safety needs and engaging students' sense of purpose reinforce persistence. A mentor program is a possible cooperative effort between student personnel and…

  12. [Gastroduodenal intussusception causing gastric retention.

    DEFF Research Database (Denmark)

    Alamili, M.; Berg, J.O.; Lindstrom, C.

    2008-01-01

    A case of gastroduodenal intussusception caused by a duodenal lipoma is presented. The condition was characterized by severe upper gastrointestinal retention, epigastric pain and weight loss. The mass was diagnosed by CT scan. The diagnosis was confirmed by operation. The patient was treated succ...

  13. Teacher Retention: An Appreciative Approach

    Science.gov (United States)

    Pesavento-Conway, Jennifer Jean

    2010-01-01

    Nationally, the problem of teacher retention compounds the unstable nature of the educational situation, especially in urban, high-needs schools. Much of the instability of urban schools is due to teacher movement, the migration of teachers from school to another school within or between school districts, particularly from high-needs schools.…

  14. [Gastroduodenal intussusception causing gastric retention.

    DEFF Research Database (Denmark)

    Alamili, M.; Berg, J.O.; Lindstrom, C.

    2008-01-01

    A case of gastroduodenal intussusception caused by a duodenal lipoma is presented. The condition was characterized by severe upper gastrointestinal retention, epigastric pain and weight loss. The mass was diagnosed by CT scan. The diagnosis was confirmed by operation. The patient was treated...

  15. Quantifying Long-term Retention of Excised Fat Grafts

    DEFF Research Database (Denmark)

    Herly, Mikkel; Ørholt, Mathias; Glovinski, Peter V.

    2017-01-01

    Background: Predicting the degree of fat graft retention is essential whenplanning reconstruction or augmentation with free fat grafting. Most surgeonsobserve volume loss over time after fat grafting; however, the portion lost toresorption after surgery is still poorly defined, and the time to re...

  16. Similarity Structure of Wave-Collapse

    DEFF Research Database (Denmark)

    Rypdal, Kristoffer; Juul Rasmussen, Jens; Thomsen, Kenneth

    1985-01-01

    Similarity transformations of the cubic Schrödinger equation (CSE) are investigated. The transformations are used to remove the explicit time variation in the CSE and reduce it to differential equations in the spatial variables only. Two different methods for similarity reduction are employed and...

  17. Radionuclide Retention in Concrete Wasteforms - FY13

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, Michelle MV; Golovich, Elizabeth C.; Wellman, Dawn M.; Crum, Jarrod V.; Lapierre, Robert; Dage, Denomy C.; Parker, Kent E.; Cordova, Elsa A.

    2013-10-15

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of low-level waste and mixed low-level waste, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  18. Radionuclide Retention in Concrete Waste Forms

    Energy Technology Data Exchange (ETDEWEB)

    Mattigod, Shas V.; Bovaird, Chase C.; Wellman, Dawn M.; Wood, Marcus I.

    2010-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how waste form performance is affected by the full range of environmental conditions within the disposal facility; the process of waste form aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of waste form aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the waste forms come in contact with groundwater. The information presented in the report provides data that 1) quantify radionuclide retention within concrete waste form materials similar to those used to encapsulate waste in the Low-Level Waste Burial Grounds (LLBG); 2) measure the effect of concrete waste form properties likely to influence radionuclide migration; and 3) quantify the stability of uranium-bearing solid phases of limited solubility in concrete.

  19. Similarity of Students' Experiences and Accuracy of Faculty and Staff Perceptions: Issues for Student Retention.

    Science.gov (United States)

    Heinemann, Allen W.; And Others

    Research on attrition of university students has recently examined "dropping out" as the culmination of a complex interactive process. In order to examine differences between successful students (persisters) and students who officially withdrew from a major university, and to examine the accuracy of faculty and staff perceptions of students'…

  20. Tritium retention in S-65 beryllium after 100 eV plasma exposure

    Energy Technology Data Exchange (ETDEWEB)

    Causey, R.A. [Sandia National Labs., Livermore, CA (United States); Longhurst, G.R. [Idaho National Engineering Laboratories, Idaho Falls, 83415 (United States); Harbin, W. [Los Alamos National Laboratories, Los Alamos, NM 87545 (United States)

    1997-02-01

    The tritium plasma experiment (TPE) has been used to measure the retention of tritium in S-65 beryllium under conditions similar to that expected for the international thermonuclear experimental reactor (ITER). Beryllium samples 2 mm thick and 50 mm in diameter were exposed to a plasma of tritium and deuterium. The particle flux striking the samples was varied from approximately 1 x 10{sup 17} (D+T)/cm{sup 2} s up to about 3 x 10{sup 18} (D+T)/cm{sup 2} s. The beryllium samples were negatively biased to elevate the energy of the impinging ions to 100 eV. The temperature of the samples was varied from 373 K to 973 K. Exposure times of 1 h were used. Subsequent to the plasma exposure, the samples were outgassed in a separate system where 99% He and 1% H{sub 2} gas was swept over the samples during heating. The sweep gas along with the released tritium was sent through an ionization chamber, through a copper oxide catalyst bed, and into a series of glycol bubblers. The amount of released tritium was determined both by the ionization chamber and by liquid scintillation counting of the glycol. Tritium retention in the beryllium disks varied from a high of 2.4 x 10{sup 17} (D+T)/cm{sup 2} at 373 K to a low of 1 x 10{sup 16} (D+T)/cm{sup 2} at 573 K. For almost every case, the tritium retention in the beryllium was less than that calculated using the C=0 boundary condition at the plasma facing surface. It is believed that this lower than expected retention is due to rapid release of tritium from the large specific surface area created in the implant zone due to the production of voids, bubbles, and blisters. (orig.).

  1. Tritium retention in S-65 beryllium after 100 eV plasma exposure

    Science.gov (United States)

    Causey, Rion A.; Longhurst, Glen R.; Harbin, Wally

    1997-02-01

    The tritium plasma experiment (TPE) has been used to measure the retention of tritium in S-65 beryllium under conditions similar to that expected for the international thermonuclear experimental reactor (ITER). Beryllium samples 2 mm thick and 50 mm in diameter were exposed to a plasma of tritium and deuterium. The particle flux striking the samples was varied from approximately 1 × 10 17 ( D + T)/ cm2s up to about 3 × 10 18 ( D + T)/ cm2s. The beryllium samples were negatively biased to elevate the energy of the impinging ions to 100 eV. The temperature of the samples was varied from 373 K to 973 K. Exposure times of 1 h were used. Subsequent to the plasma exposure, the samples were outgassed in a separate system where 99% He and 1% H 2 gas was swept over the samples during heating. The sweep gas along with the released tritium was sent through an ionization chamber, through a copper oxide catalyst bed, and into a series of glycol bubblers. The amount of released tritium was determined both by the ionization chamber and by liquid scintillation counting of the glycol. Tritium retention in the beryllium disks varied from a high of 2.4 × 10 17 ( D + T)/ cm2 at 373 K to a low of 1 × 10 16 ( D + T)/ cm2 at 573 K. For almost every case, the tritium retention in the beryllium was less than that calculated using the C = 0 boundary condition at the plasma facing surface. It is believed that this lower than expected retention is due to rapid release of tritium from the large specific surface area created in the implant zone due to the production of voids, bubbles, and blisters.

  2. Lace-Espana experimental programme on the retention of aerosols in water pools

    Energy Technology Data Exchange (ETDEWEB)

    Marcos, M. J.; Gomez, F. J.; Melches, I.; Martin, M.; Lopez, M.

    1994-07-01

    A matrix of eleven experiments on aerosol retention behaviour in submerged beds and suppression pools in water- cooled reactors under severe accident conditions has been performed, for these experiments, an intermediate scales, multi-purpose facility was set up at CIEMAT (Madrid). The facility includes various systems: aerosol generation (Csl), mixing section, injection line and pool-vessel (8 m{sup 3} ), as well as the corresponding aerosol instrumentation and a process control and data acquisition system. Some parameters have been varied in order to study their influence in the DF: steam/noncondensable ratio in the accidental mixture (0.1 to 0.9), particle size, flow rate (two regimes: bubble and jet) and injector geometry (mono orifice and multi orifice). On the other hand, some parameters have been kept constant along the experiments; pool geometry (diameter, water level), water temperature, pressure in the atmosphere above the water, submergence, injection temperature and injection time. A rapid decrease in the DF is observed as the proportion of particles measuring less than 1 {mu}m increases. Retention decreases in the case of smaller particles and considerably higher in the case of larger particles. It has been also possible to observe the influence of the injected steam fraction. Experiments with greater fraction than the saturation fraction have greater DF than those ones with smaller fractions. The jet regime with horizontal injection and the multi orifice geometry would appear to show a somewhat higher capacity of retention than those in the bubble regime under similar conditions. It would be necessary to confirm this greater capacity for retention by means of additional experimental data. This work, performed by the LACE-Espana Consortium, has been carried out in the frame of the European Commissions Shared Cost Action Programme on Reactor Safety 1988-91 on a contractual basis. (Author)18 refs.

  3. Lace-Espana experimental programme on the retention of aerosols in water pools

    International Nuclear Information System (INIS)

    Marcos, M. J.; Gomez, F. J.; Melches, I.; Martin, M.; Lopez, M.

    1994-01-01

    A matrix of eleven experiments on aerosol retention behaviour in submerged beds and suppression pools in water- cooled reactors under severe accident conditions has been performed, for these experiments, an intermediate scales, multi-purpose facility was set up at CIEMAT (Madrid). The facility includes various systems: aerosol generation (Csl), mixing section, injection line and pool-vessel (8 m 3 ), as well as the corresponding aerosol instrumentation and a process control and data acquisition system. Some parameters have been varied in order to study their influence in the DF: steam/noncondensable ratio in the accidental mixture (0.1 to 0.9), particle size, flow rate (two regimes: bubble and jet) and injector geometry (mono orifice and multi orifice). On the other hand, some parameters have been kept constant along the experiments; pool geometry (diameter, water level), water temperature, pressure in the atmosphere above the water, submergence, injection temperature and injection time. A rapid decrease in the DF is observed as the proportion of particles measuring less than 1 μm increases. Retention decreases in the case of smaller particles and considerably higher in the case of larger particles. It has been also possible to observe the influence of the injected steam fraction. Experiments with greater fraction than the saturation fraction have greater DF than those ones with smaller fractions. The jet regime with horizontal injection and the multi orifice geometry would appear to show a somewhat higher capacity of retention than those in the bubble regime under similar conditions. It would be necessary to confirm this greater capacity for retention by means of additional experimental data. This work, performed by the LACE-Espana Consortium, has been carried out in the frame of the European Commissions Shared Cost Action Programme on Reactor Safety 1988-91 on a contractual basis. (Author)18 refs

  4. Lace-Espana experimental programme on the retention of aerosols in water pools

    International Nuclear Information System (INIS)

    Marcos Crespo, M.J.; Gomez; Moreno, F. J.; Melches Serrano, I.; Martin Espigares, M.; Lopez Jimenez, J.

    1994-01-01

    A matrix of eleven experiments on aerosol retention behaviour in submerged beds and suppression pools in water-cooled reactors under severe accident conditions has been performed, for these experiments, an intermediate scale, multi-purpose facility was set up at CIEMAT (Madrid). The facility includes various systems: aerosol ageneration (CsI), mixing section, injection line and pool-vessel (8 m''3), as well as the corresponding aerosol instrumentation and a process control and data acquisition system. Some parameters have been varied in order to study their influence in the DF: steam/noncondensable ratio in the accidental mixture (0,1 to 0.9) particle size, flow rate (two regimes: bubble and jet) and injector geometry (monoorifice and multiorifice). On the other hand, some parameters have been kept constant along the experiments; pool geometry (diameter, water level), water temperature, pressure in the atmosphere above the water, submergence, injection temperature and injection time. A Rapid decrease in the DF is observed as the proportion of particles measuring les than 1 mum increases. Retention decreases in the case of smaller particles and considerably higher in the case of larger particles. It has been also possible to observe the influence of the injected steam fraction. Experiments with greater fraction than the saturation fraction have greater DF than those ones with smaller fractions. The jet regime with horizontal injection and the multiorifice geometry would appear to show a somewhat higher capacity of retention than those in the bubble regime under similar conditions. It would be necessary to confirm this greater capacity for retention by means of additional experimental data. This work, performed by the LACE-Espana Consortium, has been carried out in the frame of the European Commission's Shared Cost Action Programme on Reactor Safety 1988-91 on a contractual basis

  5. Integral analyses of fission product retention at mitigated thermally-induced SGTR using ARTIST experimental data

    International Nuclear Information System (INIS)

    Rýdl, Adolf; Lind, Terttaliisa; Birchley, Jonathan

    2016-01-01

    Highlights: • Source term analyses in a PWR of mitigated thermally-induced SGTR scenario performed. • Experimental ARTIST program results on aerosol scrubbing efficiency used in analyses. • Results demonstrate enhanced aerosol retention in a flooded steam generator. • High aerosol retention cannot be predicted by current theoretical scrubbing models. - Abstract: Integral source-term analyses are performed using MELCOR for a PWR Station Blackout (SBO) sequence leading to induced steam generator tube rupture (SGTR). In the absence of any mitigation measures, such a sequence can result in a containment bypass where the radioactive materials can be released directly to the environment. In some SGTR scenarios flooding of the faulted SG secondary side with water can mitigate the accident escalation and also the release of aerosol-borne and volatile radioactive materials. Data on the efficiency of aerosol scrubbing in an SG tube bundle were obtained in the international ARTIST project. In this paper ARTIST data are used directly with parametric MELCOR analyses of a mitigated SGTR sequence to provide more realistic estimates of the releases to environment in such a type of scenario or similar. Comparison is made with predictions using the default scrubbing model in MELCOR, as a representative of the aerosol scrubbing models in current integral codes. Specifically, simulations are performed for an unmitigated sequence and 2 cases where the SG secondary was refilled at different times after the tube rupture. The results, reflecting the experimental observations from ARTIST, demonstrate enhanced aerosol retention in the highly turbulent two-phase flow conditions caused by the complex geometry of the SG secondary side. This effect is not captured by any of the models currently available. The underlying physics remains only partly understood, indicating need for further studies to support a more mechanistic treatment of the retention process.

  6. Adenoid cystic carcinoma associated with mucous retention cyst of the parotid gland.

    Science.gov (United States)

    Hebbale, Manjula Advisha; Halli, Rajshekhar C; Kini, Yogesh K; Kharkar, Viraj R; Metgud, Rashmi

    2011-09-01

    Mucous retention cysts of the parotid gland are rare, and a coexistent adenoid cystic carcinoma is even an unusual occurrence. Such coexistent adenoid cystic carcinomas with mucous retention cyst of the parotid gland are difficult to diagnose clinically and, at times, stage difficulty in their management. We report a rare case of adenoid cystic carcinoma associated with mucous retention cyst of the parotid gland with its diagnostic and management dilemma in a 14-year-old adolescent girl.

  7. Mucous retention cyst of the maxillary sinus.

    Science.gov (United States)

    Ruprecht, A; Batniji, S; el-Neweihi, E

    1986-12-01

    The mucous retention cyst is not a rare phenomenon. The incidence of dental patients was determined. Of 1685 patient radiographs reviewed, 44 (2.6%) had one or more mucous retention cysts in the maxillary sinuses.

  8. Retention of Cationic Starch onto Cellulose Fibres

    Science.gov (United States)

    Missaoui, Mohamed; Mauret, Evelyne; Belgacem, Mohamed Naceur

    2008-08-01

    Three methods of cationic starch titration were used to quantify its retention on cellulose fibres, namely: (i) the complexation of CS with iodine and measurement of the absorbency of the ensuing blue solution by UV-vis spectroscopy; (ii) hydrolysis of the starch macromolecules followed by the conversion of the resulting sugars to furan-based molecules and quantifying the ensuing mixture by measuring their absorbance at a Ι of 490 nm, using the same technique as previous one and; finally (iii) hydrolysis of starch macromolecules by trifluoro-acetic acid and quantification of the sugars in the resulting hydrolysates by high performance liquid chromatography. The three methods were found to give similar results within the range of CS addition from 0 to 50 mg per g of cellulose fibres.

  9. Guide-Plane Retention in Designing Removable Partial Dentures.

    Science.gov (United States)

    Mothopi-Peri, Matshediso; Owen, C Peter

    To compare the influence of abutment teeth guide planes and guiding surfaces on retention of a removable partial denture (RPD). Extracted teeth embedded into a maxillary cast in the first premolar and second molar positions simulated two bounded saddles. Acrylic resin RPDs were made with no guide planes, then with guide planes, then with guiding surfaces added to directly contact the guide planes. The maximum loads on removal from the cast were recorded. There was a significant increase in retention force of 1.6 times when only guide planes were present and of 10.2 times when guiding surfaces intimately contacted the guide planes. The retention of acrylic resin RPDs can be substantially increased by making their guiding surfaces intimately contact the guide planes of the teeth.

  10. Retention of autobiographical memories: an Internet-based diary study.

    Science.gov (United States)

    Kristo, Gert; Janssen, Steve M J; Murre, Jaap M J

    2009-11-01

    In this online study we examined the retention of recent personal events using an Internet-based diary technique. Each participant (N=878) recorded on a website one recent personal event and was contacted after a retention interval that ranged between 2 and 46 days. We investigated how well the participants could recall the content, time, and details of their recorded event. We found a classic retention function. Details of the events were forgotten more rapidly than the content and the time of the events. There were no differences between the forgetting rates of the "who", "what" and "where" elements of the content component. Reminiscing, social sharing, pleasantness, and frequency of occurrence aided recall, but surprisingly importance and emotionality did not. They were, however, strongly associated with reminiscing and social sharing.

  11. 76 FR 24089 - Credit Risk Retention

    Science.gov (United States)

    2011-04-29

    ... 17 CFR Part 246 Department of Housing and Urban Development 24 CFR Part 267 Credit Risk Retention... 2501-AD53 Credit Risk Retention AGENCIES: Office of the Comptroller of the Currency, Treasury (OCC..., Commission, FHFA, and HUD (the Agencies) are proposing rules to implement the credit risk retention...

  12. Retention of Mohs surgeons in academic dermatology.

    Science.gov (United States)

    Zhang, Shali; Mina, Mary Alice; Brown, Marc D; Zwald, Fiona O

    2015-08-01

    Retention of academic Mohs surgeons is important for the growth of this specialty and teaching of residents and students. To examine factors that influence retention of Mohs surgeons in academics and to better understand reasons for their departure. A survey was electronically distributed to academic Mohs surgeons in the American College of Mohs Surgery, asking them to rate the importance of several variables on their decision to remain in academia. Private practice Mohs surgeons who had left academics were also surveyed. Two hundred thirty-six dermatologic surgeons completed the survey. Twenty-nine percent work full time in academics, and approximately 7% work part time. The top reasons for practicing in the academic setting are intellectual stimulation, teaching opportunities, and collaboration with other university physicians and researchers. Seventy-one percent of respondents reported they would stay in academics, 7% indicated they would not, and 22% were unsure. Unfair compensation, inadequate support staff, poor leadership, increased bureaucracy, and decreased autonomy were top reasons that may compel a Mohs surgeon to leave. Opportunities for intellectual stimulation, collaboration, and teaching remain the main draw for academic Mohs surgeons. A supportive environment, strong leadership, and establishing fair compensation are imperative in ensuring their stay.

  13. A COMPARISON OF SEMANTIC SIMILARITY MODELS IN EVALUATING CONCEPT SIMILARITY

    Directory of Open Access Journals (Sweden)

    Q. X. Xu

    2012-08-01

    Full Text Available The semantic similarities are important in concept definition, recognition, categorization, interpretation, and integration. Many semantic similarity models have been established to evaluate semantic similarities of objects or/and concepts. To find out the suitability and performance of different models in evaluating concept similarities, we make a comparison of four main types of models in this paper: the geometric model, the feature model, the network model, and the transformational model. Fundamental principles and main characteristics of these models are introduced and compared firstly. Land use and land cover concepts of NLCD92 are employed as examples in the case study. The results demonstrate that correlations between these models are very high for a possible reason that all these models are designed to simulate the similarity judgement of human mind.

  14. Testing Self-Similarity Through Lamperti Transformations

    KAUST Repository

    Lee, Myoungji

    2016-07-14

    Self-similar processes have been widely used in modeling real-world phenomena occurring in environmetrics, network traffic, image processing, and stock pricing, to name but a few. The estimation of the degree of self-similarity has been studied extensively, while statistical tests for self-similarity are scarce and limited to processes indexed in one dimension. This paper proposes a statistical hypothesis test procedure for self-similarity of a stochastic process indexed in one dimension and multi-self-similarity for a random field indexed in higher dimensions. If self-similarity is not rejected, our test provides a set of estimated self-similarity indexes. The key is to test stationarity of the inverse Lamperti transformations of the process. The inverse Lamperti transformation of a self-similar process is a strongly stationary process, revealing a theoretical connection between the two processes. To demonstrate the capability of our test, we test self-similarity of fractional Brownian motions and sheets, their time deformations and mixtures with Gaussian white noise, and the generalized Cauchy family. We also apply the self-similarity test to real data: annual minimum water levels of the Nile River, network traffic records, and surface heights of food wrappings. © 2016, International Biometric Society.

  15. Similarity increases altruistic punishment in humans.

    Science.gov (United States)

    Mussweiler, Thomas; Ockenfels, Axel

    2013-11-26

    Humans are attracted to similar others. As a consequence, social networks are homogeneous in sociodemographic, intrapersonal, and other characteristics--a principle called homophily. Despite abundant evidence showing the importance of interpersonal similarity and homophily for human relationships, their behavioral correlates and cognitive foundations are poorly understood. Here, we show that perceived similarity substantially increases altruistic punishment, a key mechanism underlying human cooperation. We induced (dis)similarity perception by manipulating basic cognitive mechanisms in an economic cooperation game that included a punishment phase. We found that similarity-focused participants were more willing to punish others' uncooperative behavior. This influence of similarity is not explained by group identity, which has the opposite effect on altruistic punishment. Our findings demonstrate that pure similarity promotes reciprocity in ways known to encourage cooperation. At the same time, the increased willingness to punish norm violations among similarity-focused participants provides a rationale for why similar people are more likely to build stable social relationships. Finally, our findings show that altruistic punishment is differentially involved in encouraging cooperation under pure similarity vs. in-group conditions.

  16. Renewing the Respect for Similarity

    Directory of Open Access Journals (Sweden)

    Shimon eEdelman

    2012-07-01

    Full Text Available In psychology, the concept of similarity has traditionally evoked a mixture of respect, stemmingfrom its ubiquity and intuitive appeal, and concern, due to its dependence on the framing of the problemat hand and on its context. We argue for a renewed focus on similarity as an explanatory concept, bysurveying established results and new developments in the theory and methods of similarity-preservingassociative lookup and dimensionality reduction — critical components of many cognitive functions, aswell as of intelligent data management in computer vision. We focus in particular on the growing familyof algorithms that support associative memory by performing hashing that respects local similarity, andon the uses of similarity in representing structured objects and scenes. Insofar as these similarity-basedideas and methods are useful in cognitive modeling and in AI applications, they should be included inthe core conceptual toolkit of computational neuroscience.

  17. Influence of the mechanical properties of resilient denture liners on the retention of overdenture attachments.

    Science.gov (United States)

    Kubo, Keitaro; Koike, Takashi; Ueda, Takayuki; Sakurai, Kaoru

    2018-03-15

    Information is lacking about the selection criteria for silicone resilient denture liners applied as a matrix material for attachments on overdentures. The purpose of this in vitro study was to investigate the mechanical properties of silicone resilient denture liners and their influence on the initial retention force of overdenture attachments and the reduction in retention force over time. Nine types of silicone resilient denture liner were injected and fixed to the matrix section of an experimental denture base. They were then fitted to an epoxy resin model that simulated the residual ridge with a patrix ball attachment (n=10). The retention force of the denture was measured with a digital force gauge, and the maximum force of traction (N) was regarded as the initial retention force. The retention force reduction (N) after repeated insertion and removal (n=5) was calculated by subtracting the retention force after 3348 cycles (3-year simulated insertion and removal) from the initial retention force. The intaglio of the matrix was observed with a scanning electron microscope (SEM) before and after the 3348 cycles. Four mechanical properties (hardness, strain-in-compression, tensile strength, and arithmetic mean roughness) of the resilient denture liners were measured. One-way ANOVA of the initial retention force of each lining material was performed, followed by the Scheffe test (α=.05). Pearson correlation analysis was used (α=.05) to analyze correlations of the initial retention force with the retention force reduction after insertion and removal and the mechanical properties of each material. Multiple regression analysis with the stepwise method extracted the initial retention force and the retention force reduction as dependent variables, and the resilient denture liner mechanical properties as explanatory variables (α=.05). The initial retention force of the resilient denture liners was 1.3 to 5.4 N. Multiple comparisons showed significant differences in

  18. Deuterium retention in liquid lithium

    International Nuclear Information System (INIS)

    Baldwin, M.J.; Doerner, R.P.; Luckhardt, S.C.; Conn, R.W.

    2002-01-01

    Measurements of deuterium retention in samples of lithium exposed in the liquid state to deuterium plasma are reported. Retention was measured as a function of plasma ion dose in the range 6x10 19 -4x10 22 D atoms and exposure temperature between 523 and 673 K using thermal desorption spectrometry. The results are consistent with the full uptake of all deuterium ions incident on the liquid metal surface and are found to be independent of the temperature of the liquid lithium over the range explored. Full uptake, consistent with very low recycling, continues until the sample is volumetrically converted to lithium deuteride. This occurs for exposure temperatures where the gas pressure during exposure was both below and slightly above the corresponding decomposition pressure for LiD in Li. (author)

  19. Strategies to enhance participant recruitment and retention in research involving a community-based population.

    Science.gov (United States)

    McCullagh, Marjorie C; Sanon, Marie-Anne; Cohen, Michael A

    2014-11-01

    Challenges associated with recruiting and retaining community-based populations in research studies have been recognized yet remain of major concern for researchers. There is a need for exchange of recruitment and retention techniques that inform recruitment and retention strategies. Here, the authors discuss a variety of methods that were successful in exceeding target recruitment and retention goals in a randomized clinical trial of hearing protector use among farm operators. Recruitment and retention strategies were 1) based on a philosophy of mutually beneficial engagement in the research process, 2) culturally appropriate, 3) tailored to the unique needs of partnering agencies, and 4) developed and refined in a cyclical and iterative process. Sponsoring organizations are interested in cost-effective recruitment and retention strategies, particularly relating to culturally and ethnically diverse groups. These approaches may result in enhanced subject recruitment and retention, concomitant containment of study costs, and timely accomplishment of study aims. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Facilitating student retention in online graduate nursing education programs: a review of the literature.

    Science.gov (United States)

    Gazza, Elizabeth A; Hunker, Diane F

    2014-07-01

    Online education, a form of distance education, provides students with opportunities to engage in lifelong learning without the restrictions of time and space. However, while this approach meets the needs of employed nursing professionals, it poses some challenges for educators. Student retention is one such challenge. Student retention rates serve as measures of program quality and are reported to accrediting bodies. Therefore, it is imperative that administrators and program faculty implement comprehensive programs to ensure student retention. This review of the literature was designed to identify strategies to improve student retention in online graduate nursing education programs. The review includes 23 articles that address models, research, and best practices supported in nursing and higher education. The findings indicate that student retention in online programs is a multidimensional problem requiring a multifaceted approach. Recommendations for facilitating retention in online nursing programs include ensuring social presence and program and course quality, and attentiveness to individual student characteristics. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. The recent similarity hypotheses to describe water infiltration into homogeneous soils

    OpenAIRE

    Reichardt,Klaus; Timm,Luís Carlos; Dourado-Neto,Durval

    2016-01-01

    ABSTRACT A similarity hypothesis recently presented to describe horizontal infiltration into homogeneous soils, developed for coarse-textured soils like sieved marine sand, implies that the soil water retention function θ(h) is the mirror image of an extended Boltzmann transform function θ(λ2). A second hypothesis applicable to vertical infiltration suggests that the soil water retention function θ(h) is also the mirror image of the soil water profile θ(z). Using prev...

  2. Plunger with simple retention valve

    International Nuclear Information System (INIS)

    Fekete, A.V.

    1987-01-01

    This patent describes a positive displacement retention valve apparatus in which the actual flow equals the theoretical maximum flow through the retention valve. The apparatus includes, in combination, a confined fluid flow conduit, a piston adapted for reciprocal movement within the fluid flow conduit between upstream and downstream limit positions, piston reciprocating means, and pressure responsive check valve means located upstream with respect to the piston in the fluid flow conduit. The pressure responsive check valve means operable to permit fluid flow therethrough in a downstream direction toward the piston, and to preclude fluid flow therethrough in an opposite direction. The piston is composed of parts which are relatively movable with respect to one another. The piston includes a simple retention valve consisting of a plug means, a cylinder having a minimum and a maximum internal cross section flow area therein and being reciprocal within the confined fluid flow conduit, and a seat on the cylinder for the plug means. The piston reciprocating means are operatively connected to the plug means

  3. In search of late time evolution self-similar scaling laws of Rayleigh-Taylor and Richtmyer-Meshkov hydrodynamic instabilities - recent theorical advance and NIF Discovery-Science experiments

    Science.gov (United States)

    Shvarts, Dov

    2017-10-01

    Hydrodynamic instabilities, and the mixing that they cause, are of crucial importance in describing many phenomena, from very large scales such as stellar explosions (supernovae) to very small scales, such as inertial confinement fusion (ICF) implosions. Such mixing causes the ejection of stellar core material in supernovae, and impedes attempts at ICF ignition. The Rayleigh-Taylor instability (RTI) occurs at an accelerated interface between two fluids with the lower density accelerating the higher density fluid. The Richtmyer-Meshkov (RM) instability occurs when a shock wave passes an interface between the two fluids of different density. In the RTI, buoyancy causes ``bubbles'' of the light fluid to rise through (penetrate) the denser fluid, while ``spikes'' of the heavy fluid sink through (penetrate) the lighter fluid. With realistic multi-mode initial conditions, in the deep nonlinear regime, the mixing zone width, H, and its internal structure, progress through an inverse cascade of spatial scales, reaching an asymptotic self-similar evolution: hRT =αRT Agt2 for RT and hRM =αRM tθ for RM. While this characteristic behavior has been known for years, the self-similar parameters αRT and θRM and their dependence on dimensionality and density ratio have continued to be intensively studied and a relatively wide distribution of those values have emerged. This talk will describe recent theoretical advances in the description of this turbulent mixing evolution that sheds light on the spread in αRT and θRM. Results of new and specially designed experiments, done by scientists from several laboratories, were performed recently using NIF, the only facility that is powerful enough to reach the self-similar regime, for quantitative testing of this theoretical advance, will be presented.

  4. Self-similar cosmological models

    Energy Technology Data Exchange (ETDEWEB)

    Chao, W Z [Cambridge Univ. (UK). Dept. of Applied Mathematics and Theoretical Physics

    1981-07-01

    The kinematics and dynamics of self-similar cosmological models are discussed. The degrees of freedom of the solutions of Einstein's equations for different types of models are listed. The relation between kinematic quantities and the classifications of the self-similarity group is examined. All dust local rotational symmetry models have been found.

  5. Self-similar factor approximants

    International Nuclear Information System (INIS)

    Gluzman, S.; Yukalov, V.I.; Sornette, D.

    2003-01-01

    The problem of reconstructing functions from their asymptotic expansions in powers of a small variable is addressed by deriving an improved type of approximants. The derivation is based on the self-similar approximation theory, which presents the passage from one approximant to another as the motion realized by a dynamical system with the property of group self-similarity. The derived approximants, because of their form, are called self-similar factor approximants. These complement the obtained earlier self-similar exponential approximants and self-similar root approximants. The specific feature of self-similar factor approximants is that their control functions, providing convergence of the computational algorithm, are completely defined from the accuracy-through-order conditions. These approximants contain the Pade approximants as a particular case, and in some limit they can be reduced to the self-similar exponential approximants previously introduced by two of us. It is proved that the self-similar factor approximants are able to reproduce exactly a wide class of functions, which include a variety of nonalgebraic functions. For other functions, not pertaining to this exactly reproducible class, the factor approximants provide very accurate approximations, whose accuracy surpasses significantly that of the most accurate Pade approximants. This is illustrated by a number of examples showing the generality and accuracy of the factor approximants even when conventional techniques meet serious difficulties

  6. Dynamic similarity in erosional processes

    Science.gov (United States)

    Scheidegger, A.E.

    1963-01-01

    A study is made of the dynamic similarity conditions obtaining in a variety of erosional processes. The pertinent equations for each type of process are written in dimensionless form; the similarity conditions can then easily be deduced. The processes treated are: raindrop action, slope evolution and river erosion. ?? 1963 Istituto Geofisico Italiano.

  7. Personalized recommendation with corrected similarity

    International Nuclear Information System (INIS)

    Zhu, Xuzhen; Tian, Hui; Cai, Shimin

    2014-01-01

    Personalized recommendation has attracted a surge of interdisciplinary research. Especially, similarity-based methods in applications of real recommendation systems have achieved great success. However, the computations of similarities are overestimated or underestimated, in particular because of the defective strategy of unidirectional similarity estimation. In this paper, we solve this drawback by leveraging mutual correction of forward and backward similarity estimations, and propose a new personalized recommendation index, i.e., corrected similarity based inference (CSI). Through extensive experiments on four benchmark datasets, the results show a greater improvement of CSI in comparison with these mainstream baselines. And a detailed analysis is presented to unveil and understand the origin of such difference between CSI and mainstream indices. (paper)

  8. Estradiol enhances retention but not organization of hippocampus-dependent memory in intact male mice.

    Science.gov (United States)

    Al Abed, Alice Shaam; Sellami, Azza; Brayda-Bruno, Laurent; Lamothe, Valérie; Noguès, Xavier; Potier, Mylène; Bennetau-Pelissero, Catherine; Marighetto, Aline

    2016-07-01

    Because estrogens have mostly been studied in gonadectomized females, effects of chronic exposure to environmental estrogens in the general population are underestimated. Estrogens can enhance hippocampus-dependent memory through the modulation of information storage. However, declarative memory, the hippocampus-dependent memory of facts and events, demands more than abilities to retain information. Specifically, memory of repetitive events of everyday life such as "where I parked" requires abilities to organize/update memories to prevent proactive interference from similar memories of previous "parking events". Whether such organizational processes are estrogen-sensitive is unknown. We here studied, in intact young and aged adult mice, drinking-water (1μM) estradiol effects on both retention and organizational components of hippocampus-dependent memory, using a radial-maze task of everyday-like memory. Demand on retention vs organization was manipulated by varying the time-interval separating repetitions of similar events. Estradiol increased performance in young and aged mice under minimized organizational demand, but failed to improve the age-associated memory impairment and diminished performance in young mice under high organizational demand. In fact, estradiol prolonged mnemonic retention of successive events without improving organization abilities, hence resulted in more proactive interference from irrelevant memories. c-Fos imaging of testing-induced brain activations showed that the deterioration of young memory was associated with dentate gyrus dysconnectivity, reminiscent of that seen in aged mice. Our findings support the view that estradiol is promnesic but also reveal that such property can paradoxically impair memory. These findings have important outcomes regarding health issues relative to the impact of environmental estrogens in the general population. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Towards Personalized Medicine: Leveraging Patient Similarity and Drug Similarity Analytics

    Science.gov (United States)

    Zhang, Ping; Wang, Fei; Hu, Jianying; Sorrentino, Robert

    2014-01-01

    The rapid adoption of electronic health records (EHR) provides a comprehensive source for exploratory and predictive analytic to support clinical decision-making. In this paper, we investigate how to utilize EHR to tailor treatments to individual patients based on their likelihood to respond to a therapy. We construct a heterogeneous graph which includes two domains (patients and drugs) and encodes three relationships (patient similarity, drug similarity, and patient-drug prior associations). We describe a novel approach for performing a label propagation procedure to spread the label information representing the effectiveness of different drugs for different patients over this heterogeneous graph. The proposed method has been applied on a real-world EHR dataset to help identify personalized treatments for hypercholesterolemia. The experimental results demonstrate the effectiveness of the approach and suggest that the combination of appropriate patient similarity and drug similarity analytics could lead to actionable insights for personalized medicine. Particularly, by leveraging drug similarity in combination with patient similarity, our method could perform well even on new or rarely used drugs for which there are few records of known past performance. PMID:25717413

  10. Uncovering client retention antecedents in service organizations

    Directory of Open Access Journals (Sweden)

    Mari Jansen van Rensburg

    2014-01-01

    Full Text Available This paper develops a multi-dimensional model of retention to provide a more complete and integrated view of client retention and its determinants in service contexts. To uncover the antecedents of client retention, social and economic exchanges were reviewed under the fundamental ideas of the Social Exchange Theory. Findings from a survey of senior South African advertising executives suggest that client retention is the result of evaluative as well as relational factors that can influence client responses. Despite contractual obligations, advertisers are willing to pay the costs and make the sacrifices of switching should their expectations be unmet. An important contribution of this study is the use of multi-item scales to measure retention. The model developed provides valuable insight to agencies on client retention management and the optimal allocation of resources for maximum customer equity. This model may also be applied to other service organisations to provide insight to client retention.

  11. Visual and Phonological Similarity Effects in Verbal Immediate Serial Recall: A Test with Kanji Materials

    Science.gov (United States)

    Saito, Satoru; Logie, Robert H.; Morita, Aiko; Law, Anna

    2008-01-01

    In a series of three experiments, native speakers of Japanese performed serial ordered written recall of visually presented Japanese kanji characters that varied systematically in visual and phonological similarity. Overall effects of phonological similarity were observed for retention of serial order under silent reading in Experiments 1 and 3…

  12. Psychological determinants of job retention in multiple sclerosis.

    Science.gov (United States)

    Ford, Helen L; Wicks, Charlotte R; Stroud, Amanda; Tennant, Alan

    2018-01-01

    Maintaining paid work is a key issue for people with multiple sclerosis (PwMS). Different factors, including psychological attributes, can influence job retention. Understanding their role should inform potential interventions to help PwMS retain employment. The aim of this study was to identify the key factors which improve job retention in an employed cohort of PwMS. This three-year longitudinal study used validated self-completed measures of physical and psychological factors at four time points over 28 months. Of 208 employed PwMS, just over 1 in 10 was no longer working at the end of the study. Three variables were predictive of continuing employment; low 'work instability' at baseline increased the odds of job retention by a factor of 12.76; high levels of self-efficacy by a factor of 4.66 and being less than 50 years of age increased the odds of job retention by a factor of 3.90. Path analysis demonstrated the mediating role of self-efficacy between the physical impact of MS and the level of work instability at exit. Screening for work instability and self-efficacy in a clinical setting followed by appropriate interventions to increase self-efficacy and reduce work instability could aid job retention in MS.

  13. Phonological similarity and orthographic similarity affect probed serial recall of Chinese characters.

    Science.gov (United States)

    Lin, Yi-Chen; Chen, Hsiang-Yu; Lai, Yvonne C; Wu, Denise H

    2015-04-01

    The previous literature on working memory (WM) has indicated that verbal materials are dominantly retained in phonological representations, whereas other linguistic information (e.g., orthography, semantics) only contributes to verbal WM minimally, if not negligibly. Although accumulating evidence has suggested that multiple linguistic components jointly support verbal WM, the visual/orthographic contribution has rarely been addressed in alphabetic languages, possibly due to the difficulty of dissociating the effects of word forms from the effects of their pronunciations in relatively shallow orthography. In the present study, we examined whether the orthographic representations of Chinese characters support the retention of verbal materials in this language of deep orthography. In Experiments 1a and 2, we independently manipulated the phonological and orthographic similarity of horizontal and vertical characters, respectively, and found that participants' accuracy of probed serial recall was reduced by both similar pronunciations and shared phonetic radicals in the to-be-remembered stimuli. Moreover, Experiment 1b showed that only the effect of phonological, but not that of orthographic, similarity was affected by concurrent articulatory suppression. Taken together, the present results indicate the indispensable contribution of orthographic representations to verbal WM of Chinese characters, and suggest that the linguistic characteristics of a specific language not only determine long-term linguistic-processing mechanisms, but also delineate the organization of verbal WM for that language.

  14. Forecasting Mobile Games' Retention using Weka

    Directory of Open Access Journals (Sweden)

    Roxana Ioana STIRCU

    2016-08-01

    Full Text Available In the actual market, when thousands of mobile, PC or console games are released every year, developing and publishing a successful and profitable game is a very challenging process. The gaming industry is very competitive, and all the distribution channels are full of projects competing for players. More and more companies are investing a lot of time and resources in developing an effective way to save and store all the data used and generated by their game's users. In order to develop effective and successful projects, companies adopted a lot of tools and techniques from other domains, like Statistics, Business Intelligence, or Project Management. The method most currently used is Analytics, defined as the process of discovering and communicating patterns in data, to better understand players' behavior, analyze their in-game interaction, and predicting their next in-game actions. This represents a huge step forward for the gaming industry, towards successful projects and user-tailored gaming experience. In this article the problem of users' retention is discussed, and a regression model is proposed in order to forecast players' retention, and prevent players from leaving the game.

  15. A pin-assisted retention technique for resin-bonded restorations.

    Science.gov (United States)

    Miara, P; Touati, B

    1992-09-01

    The value of pins for auxiliary retention has been demonstrated many times. The use of pins with resin-bonded restorations allows for improved aesthetics and less tooth reduction while increasing resistance to dislodging forces. Clinical and technical procedures for resin-bonded bridges with pin-assisted retention are presented.

  16. On self-similarity of crack layer

    Science.gov (United States)

    Botsis, J.; Kunin, B.

    1987-01-01

    The crack layer (CL) theory of Chudnovsky (1986), based on principles of thermodynamics of irreversible processes, employs a crucial hypothesis of self-similarity. The self-similarity hypothesis states that the value of the damage density at a point x of the active zone at a time t coincides with that at the corresponding point in the initial (t = 0) configuration of the active zone, the correspondence being given by a time-dependent affine transformation of the space variables. In this paper, the implications of the self-similarity hypothesis for qusi-static CL propagation is investigated using polystyrene as a model material and examining the evolution of damage distribution along the trailing edge which is approximated by a straight segment perpendicular to the crack path. The results support the self-similarity hypothesis adopted by the CL theory.

  17. Cracks in bread crust cause longer crispness retention

    NARCIS (Netherlands)

    Hirte, A.; Hamer, R.J.; Hoffmann, L.; Primo Martin, C.

    2013-01-01

    Crispness is among the most important factors that the consumer uses to assess the quality of crispy bread. However, this quality attribute is rapidly lost after baking. It is known that crispness retention can be increased more than eight times by enhancing the water vapor permeability of the

  18. The predictive ability of different customer feedback metrics for retention

    NARCIS (Netherlands)

    de Haan, Evert; Verhoef, Peter C.; Wiesel, Thorsten

    This study systematically compares different customer feedback metrics (CFMs) - namely customer satisfaction, the Net Promoter Score, and the Customer Effort Score - to test their ability to predict retention across a wide range of industries. We classify the CFMs according to a time focus (past,

  19. New Estimates of the Effect of Unemployment on Enlisted Retention

    Science.gov (United States)

    1985-07-01

    S14cw’tity lafication) New Estimates of the Effect of Umemployment on Enlisted Retention 12. PERSONAL AUTHOR(S) Ile, TYPE OF REPORT 3b~. TIME COVERED...wider swings in the umemployment rate during recent years, relative military pay has played at least as important a role as the unemployment rate in

  20. Estimation of soil water retention curve using fractal dimension ...

    African Journals Online (AJOL)

    The soil water retention curve (SWRC) is a fundamental hydraulic property majorly used to study flow transport in soils and calculate plant-available water. Since, direct measurement of SWRC is time-consuming and expensive, different models have been developed to estimate SWRC. In this study, a fractal-based model ...

  1. A national study of the retention of Irish opiate users in methadone substitution treatment

    LENUS (Irish Health Repository)

    Mullen, Louise

    2012-07-02

    Background: Retention in treatment is a key indicator of methadone treatment success. The study aims to identify factors that are associated with retention. Objectives: To determine retention in treatment at 12 months for Irish opiate users in methadone substitution treatment and to indicate factors that increase the likelihood of retention. Methods: National cohort study of randomly selected opiate users commencing methadone treatment in 1999, 2001, and 2003 (n = 1269). Results: Sixty-one percent of patients attending methadone treatment remained in continuous treatment for more than 1 year. Retention in treatment at 12 months was associated with age, gender, facility type, and methadone dose. Age and gender were no longer significant when adjusted for other variables in the model. Those who attended a specialist site were twice as likely to leave methadone treatment within 12 months compared with those who attended a primary care physician. The most important predictor of retention in treatment was methadone dose. Those who received <60 mg of methadone were three times more likely to leave treatment. Conclusion: Retention in methadone treatment is high in Ireland in a variety of settings. The main factors influencing retention in methadone treatment was an adequate methadone dose and access to a range of treatment settings including from primary care physicians. Scientific Significance: Providing an adequate dose of methadone during treatment will increase the likelihood of treatment retention. Methadone treatment by the primary care physician is a successful method of retaining opioid users in treatment.

  2. Impact of Motivational Pharmacotherapy on Treatment Retention among Depressed Latinos

    Science.gov (United States)

    Lewis-Fernández, Roberto; Balán, Iván C.; Patel, Sapana R.; Sánchez-Lacay, J. Arturo; Alfonso, César; Gorritz, Magdaliz; Blanco, Carlos; Schmidt, Andrew; Jiang, Huiping; Schneier, Franklin; Moyers, Theresa B.

    2015-01-01

    Compared to non-Latino Whites, US racial/ethnic minority groups show higher non-adherence with outpatient antidepressant therapy, including lower retention, despite adjusting for sociodemographic and insurance covariates. Culturally salient concerns about antidepressants leading to ambivalence about treatment engagement may contribute to this discrepancy. To improve treatment adherence among depressed Latinos, we developed Motivational Pharmacotherapy, a novel approach that combines Motivational Interviewing, standard pharmacotherapy, and attention to Latino cultural concerns about antidepressants. This 12-week, open-trial, pre-post pilot study assessed the impact of Motivational Pharmacotherapy on antidepressant therapy retention, response (symptoms, functioning, and quality of life), and visit duration among N=50 first-generation Latino outpatients with Major Depressive Disorder. At study endpoint, 20% of patients discontinued treatment, with a mean therapy duration of 74.2 out of 84 days. Patients’ symptoms, psychosocial functioning, and quality of life improved significantly. Mean visit length was 36.7 minutes for visit 1 and 24.3 minutes for subsequent visits, compatible with use in community clinics. Responder and remitter rates were 82% and 68%. Compared to published Latino proportions of non-retention (32-53%) and previous studies at our clinic with similar samples and medications (36-46%), Motivational Pharmacotherapy appears to improve Latino retention in antidepressant therapy, and should be investigated further in controlled designs. PMID:23965261

  3. Nitrogen retention in contrasting temperate forests exposed to high nitrogen deposition

    Science.gov (United States)

    Staelens, J.; Adriaenssens, S.; Wuyts, K.; Verheyen, K.; Boeckx, P. F.

    2011-12-01

    A better understanding of factors affecting nitrogen (N) retention is needed to assess the impact of changing anthropogenic N emissions and climatic conditions on N cycling and N loss by terrestrial ecosystems. Retention of N has been demonstrated for a wide range of forests, including ecosystems exposed to chronically enhanced N deposition, but it is still unclear which factors determine this N retention capacity. Therefore, we examined the possible effects of forest type on N retention using stable N isotopes. The study was carried out in adjacent equal-aged deciduous (pedunculate oak (Quercus robur L.)) and coniferous (Scots pine (Pinus sylvestris L.)) stands with a similar stand history and growing on a well-drained sandy soil in a region with enhanced N deposition (Belgium). The N input-output budgets and gross soil N transformation rates differed significantly between the two stands. The forest floor was exposed to a high inorganic N input from atmospheric deposition, which was nearly twice as high in the pine stand (33 ± 2 kg N ha-1 yr-1; mean ± standard error) as in the oak stand (18 ± 1 kg N ha-1 yr-1). The N input was reflected in the soil solution under the rooting zone, but the mean nitrate concentration was eight times higher under pine (19 ± 5 mg N L-1) than under oak (2.3 ± 0.9 mg N L-1). Gross N dynamics in the mineral topsoil were determined by in situ 15N labelling of undisturbed soil cores combined with numerical data analysis. Gross N mineralization was two times faster in the oak soil while nitrate production was two times faster in the pine soil, indicating a dominant effect of vegetation cover on soil N cycling. The higher gross nitrification, particularly due to oxidation of organic N, in the pine soil compared to the oak soil, combined with negligible nitrate immobilization, was in line with the higher nitrate leaching under the pine forest. On a larger spatial and temporal scale, the fate of dissolved inorganic N within these forests

  4. High retention of 15N-labeled nitrogen deposition in a nitrogen saturated old-growth tropical forest

    DEFF Research Database (Denmark)

    Gurmesa, Geshere Abdisa; Lu, Xiankai; Gundersen, Per

    2016-01-01

    ecosystem compartments were quantified 4 months after the last addition. Tracer recoveries in soil solution were monitored monthly to quantify leaching losses. Total tracer recovery in plant and soil (N retention) in the control plots was 72% and similar to those observed in temperate forests. The retention...

  5. Improved Intranasal Retentivity and Transnasal Absorption Enhancement by PEGylated Poly-l-ornithine

    Directory of Open Access Journals (Sweden)

    Yusuke Kamiya

    2018-01-01

    Full Text Available We reported that the introduction of polyethylene glycol (PEG to poly-l-ornithine (PLO, which is an homopolymeric basic amino acid having absorption-enhancement ability, prolonged retention time in an in vitro inclined plate test, probably due to an increase in viscosity caused by PEGylation. The aim of the present study is to investigate whether the introduction of PEG chains to PLO improves intranasal retention and transnasal absorption in vivo. We performed intranasal administration experiments using PLO and PEG-PLO with a model drug, fluorescein isothiocyanate dextran (FD-4, in rats under closed and open systems. In the open system, transition of plasma FD-4 concentration after co-administration with unmodified PLO was low, and the area under the plasma concentration-time curve (AUC decreased to about 60% of that in the closed system. In contrast, the AUC after co-administration with PEG-PLO in the open system was about 90% of that in the closed system, and the transition of plasma FD-4 concentration and FD-4 absorption profile were similar to those of the closed system. These findings indicate that introducing PEG chains to homopolymeric basic amino acids (HPBAAs is a very useful method for developing a functional absorption enhancer that can exhibit an efficient in vivo absorption-enhancing effect.

  6. Similarity measures for face recognition

    CERN Document Server

    Vezzetti, Enrico

    2015-01-01

    Face recognition has several applications, including security, such as (authentication and identification of device users and criminal suspects), and in medicine (corrective surgery and diagnosis). Facial recognition programs rely on algorithms that can compare and compute the similarity between two sets of images. This eBook explains some of the similarity measures used in facial recognition systems in a single volume. Readers will learn about various measures including Minkowski distances, Mahalanobis distances, Hansdorff distances, cosine-based distances, among other methods. The book also summarizes errors that may occur in face recognition methods. Computer scientists "facing face" and looking to select and test different methods of computing similarities will benefit from this book. The book is also useful tool for students undertaking computer vision courses.

  7. Similarity in Bilateral Isolated Internal Orbital Fractures.

    Science.gov (United States)

    Chen, Hung-Chang; Cox, Jacob T; Sanyal, Abanti; Mahoney, Nicholas R

    2018-04-13

    In evaluating patients sustaining bilateral isolated internal orbital fractures, the authors have observed both similar fracture locations and also similar expansion of orbital volumes. In this study, we aim to investigate if there is a propensity for the 2 orbits to fracture in symmetrically similar patterns when sustaining similar trauma. A retrospective chart review was performed studying all cases at our institution of bilateral isolated internal orbital fractures involving the medial wall and/or the floor at the time of presentation. The similarity of the bilateral fracture locations was evaluated using the Fisher's exact test. The bilateral expanded orbital volumes were analyzed using the Wilcoxon signed-rank test to assess for orbital volume similarity. Twenty-four patients with bilateral internal orbital fractures were analyzed for fracture location similarity. Seventeen patients (70.8%) had 100% concordance in the orbital subregion fractured, and the association between the right and the left orbital fracture subregion locations was statistically significant (P < 0.0001). Fifteen patients were analyzed for orbital volume similarity. The average orbital cavity volume was 31.2 ± 3.8 cm on the right and 32.0 ± 3.7 cm on the left. There was a statistically significant difference between right and left orbital cavity volumes (P = 0.0026). The data from this study suggest that an individual who suffers isolated bilateral internal orbital fractures has a statistically significant similarity in the location of their orbital fractures. However, there does not appear to be statistically significant similarity in the expansion of the orbital volumes in these patients.

  8. Is the population level link between drinking and harm similar for women and men?--a time series analysis with focus on gender-specific drinking and alcohol-related hospitalizations in Sweden.

    Science.gov (United States)

    Engdahl, Barbro; Ramstedt, Mats

    2011-08-01

    A question that has not been addressed in the literature is whether the population level association between alcohol and harm differs between men and women. The main aim of this article is to fill this gap by analysing recently collected time series data of male and female self-reported drinking in relation to gender-specific harm indicators in Sweden. Male and female per capita and risk consumption was estimated on the basis of self-reported data from monthly alcohol surveys for the period 2002-07. Overall per capita consumption including recorded sales and estimates of unrecorded consumption were also collected for the same period. Alcohol-related hospitalizations were used as indicators of alcohol-related harm. Data were aggregated into quarterly observations and analysed by means of time series analyses (ARIMA-modelling). Overall per capita consumption was significantly related to both male and female alcohol-related hospitalizations. Male per capita consumption and risk consumption were also significantly related to alcohol-related hospitalizations among men. Female per capita consumption and risk consumption had also a positive association with alcohol-related hospitalizations but statistical significance was only reached for alcohol poisonings where the association was even stronger than for men. Changes in alcohol consumption in Sweden was associated with changes in male and female alcohol-related hospitalizations also in analyses based on gender-specific consumption measures. There was no clear evidence that the population level association between alcohol and harm differed between men and women.

  9. Retention of nitrous gases in scrubber columns

    International Nuclear Information System (INIS)

    Nakazone, A.K.; Costa, R.C.; Lobao, A.S.T.; Matsuda, H.T.; Araujo, B.F. de

    1988-01-01

    During the UO 2 dissolution in nitric acid, some different species of NO (sub)x are released. The off gas can either be refluxed to the dissolver or be released and retained on special colums. The final composition of the solution is the main parameter to take in account. A process for nitrous gases retention using scrubber colums containing H 2 O or diluted HNO 3 is presented. Chemiluminescence measurement was employed to NO x evaluation before and after scrubing. Gas flow, temperature, residence time are the main parameters considered in this paper. For the dissolution of 100g UO 2 in 8M nitric acid, a 6NL/h O 2 flow was the best condition for the NO/NO 2 oxidation with maximum absorption in the scrubber columns. (author) [pt

  10. Retention of krypton on polymethyl methacrylate

    International Nuclear Information System (INIS)

    Ciric, M.M.; Cvjeticanin, N.M.; Radak, B.B.

    1975-01-01

    Retention of krypton on polymethyl methacrylate was studied as a function of kryptonation pressure (P), temperature (T) and time (t). It was found that the dependence of the retained quantity on P, T, and t is in accordance with the diffusion theory. The optimum results (i.e., the maximum retained quantity and the best stability of the kryptonate) were obtained at elevated kryptonation temperatures (200 0 C). The diffusion coefficients of krypton in polymethyl methacrylate, determined from the dekryptonation process, vary from 1 x 10 -10 cm 2 /s to 0.2 x 10 -10 cm 2 /s for samples kryptonated at 20 0 C and 200 0 C respectively. The results have been discussed from the viewpoint of radiation and thermal stability of kryptonated polymethyl methacrylate. Inadequate radiation stability could be the main obstacle for practical purposes. (U.S.)

  11. Actual drawing of histological images improves knowledge retention.

    Science.gov (United States)

    Balemans, Monique C M; Kooloos, Jan G M; Donders, A Rogier T; Van der Zee, Catharina E E M

    2016-01-01

    Medical students have to process a large amount of information during the first years of their study, which has to be retained over long periods of nonuse. Therefore, it would be beneficial when knowledge is gained in a way that promotes long-term retention. Paper-and-pencil drawings for the uptake of form-function relationships of basic tissues has been a teaching tool for a long time, but now seems to be redundant with virtual microscopy on computer-screens and printers everywhere. Several studies claimed that, apart from learning from pictures, actual drawing of images significantly improved knowledge retention. However, these studies applied only immediate post-tests. We investigated the effects of actual drawing of histological images, using randomized cross-over design and different retention periods. The first part of the study concerned esophageal and tracheal epithelium, with 384 medical and biomedical sciences students randomly assigned to either the drawing or the nondrawing group. For the second part of the study, concerning heart muscle cells, students from the previous drawing group were now assigned to the nondrawing group and vice versa. One, four, and six weeks after the experimental intervention, the students were given a free recall test and a questionnaire or drawing exercise, to determine the amount of knowledge retention. The data from this study showed that knowledge retention was significantly improved in the drawing groups compared with the nondrawing groups, even after four or six weeks. This suggests that actual drawing of histological images can be used as a tool to improve long-term knowledge retention. © 2015 American Association of Anatomists.

  12. Fission-product retention in HTGR fuels

    International Nuclear Information System (INIS)

    Homan, F.J.; Kania, M.J.; Tiegs, T.N.

    1982-01-01

    Retention data for gaseous and metallic fission products are presented for both Triso-coated and Biso-coated HTGR fuel particles. Performance trends are established that relate fission product retention to operating parameters, such as temperature, burnup, and neutron exposure. It is concluded that Biso-coated particles are not adequately retentive of fission gas or metallic cesium, and Triso-coated particles which retain cesium still lose silver. Design implications related to these performance trends are identified and discussed

  13. A Study on Employee Retention Techniques

    OpenAIRE

    Savarimuthu, Dr. A; Hemalatha, N.

    2013-01-01

    The objective of perusing this study is to assess the level of satisfaction of employee retention techniques at GB Engineering Enterprises PVT Limited., Trichy.This study gains significance because of employee retention techniques can be approached from various angles. It is desirable state of existence involving retention strategies generally fall in to one of four categories salary, working conditions, job enrichment and education. These four elements together constitute. The structure of e...

  14. Revisiting Inter-Genre Similarity

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Gouyon, Fabien

    2013-01-01

    We revisit the idea of ``inter-genre similarity'' (IGS) for machine learning in general, and music genre recognition in particular. We show analytically that the probability of error for IGS is higher than naive Bayes classification with zero-one loss (NB). We show empirically that IGS does...... not perform well, even for data that satisfies all its assumptions....

  15. Fast business process similarity search

    NARCIS (Netherlands)

    Yan, Z.; Dijkman, R.M.; Grefen, P.W.P.J.

    2012-01-01

    Nowadays, it is common for organizations to maintain collections of hundreds or even thousands of business processes. Techniques exist to search through such a collection, for business process models that are similar to a given query model. However, those techniques compare the query model to each

  16. Glove boxes and similar containments

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    According to the present invention a glove box or similar containment is provided with an exhaust system including a vortex amplifier venting into the system, the vortex amplifier also having its main inlet in fluid flow connection with the containment and a control inlet in fluid flow connection with the atmosphere outside the containment. (U.S.)

  17. Job sharing: a retention strategy for nurses.

    Science.gov (United States)

    Kane, D

    1999-01-01

    Job sharing is a part-time employment alternative which offers advantages for employers interested in retaining experienced staff and nurses who are seeking a more equitable balance between work life and home life responsibilities. This quasi experimental, ex post facto research study was designed to determine if there are differences in job satisfaction, burnout, and desire to leave their position, in nurses who are employed in full-time, part-time, or job sharing positions. The sample (N = 269) was drawn from a large Canadian teaching and referral hospital. Three sample groups were developed, consisting of job sharing, full-time, and part-time nurses, respectively. Descriptive statistics were used to identify characteristics of the selected population. Analysis of variance was used to examine differences between the three employment groups on the outcome measures of job satisfaction, burnout, and desire to leave their position. The results of this study significantly support the belief that job sharing has a positive impact on job satisfaction and job retention. Implications for nursing administrators as well as individual nurses will be discussed.

  18. Specialized moisture retention eyewear for evaporative dry eye.

    Science.gov (United States)

    Waduthantri, Samanthila; Tan, Chien Hua; Fong, Yee Wei; Tong, Louis

    2015-05-01

    To evaluate the suitablity of commercially available moisture retention eyewear for treating evaporative dry eye. Eleven patients with evaporative dry eyes were prescibed moisture retention eyewear for 3 months in addition to regular lubricant eye drops. Frequency and severity of dry eye symptoms, corneal fluorescein staining and tear break up time (TBUT) were evaluated at baseline and 3-month post-treatment. Main outcome measure was global symptom score (based on severity and frequency of dry eye symptoms on a visual analog scale) and secondary outcomes were changes in sectoral corneal fluorescein staining and tear break up time (TBUT) from pre-treatment level. There was a significant improvement in dry eye symptoms after using moisture retention eyewear for 3 months (p eyes improved significantly (p dry eye symptoms in windy, air-conditioned environments or when doing vision-related daily tasks. This study shows that moisture retention eyewear might be a valuable adjunct in management of evaporative dry eye and this new design of commercially available eyewear could have a good acceptability rate.

  19. Multidimensional Scaling Visualization using Parametric Similarity Indices

    OpenAIRE

    Machado, J. A. Tenreiro; Lopes, António M.; Galhano, A.M.

    2015-01-01

    In this paper, we apply multidimensional scaling (MDS) and parametric similarity indices (PSI) in the analysis of complex systems (CS). Each CS is viewed as a dynamical system, exhibiting an output time-series to be interpreted as a manifestation of its behavior. We start by adopting a sliding window to sample the original data into several consecutive time periods. Second, we define a given PSI for tracking pieces of data. We then compare the windows for different values of the parameter, an...

  20. Music Retrieval based on Melodic Similarity

    NARCIS (Netherlands)

    Typke, R.

    2007-01-01

    This thesis introduces a method for measuring melodic similarity for notated music such as MIDI files. This music search algorithm views music as sets of notes that are represented as weighted points in the two-dimensional space of time and pitch. Two point sets can be compared by calculating how

  1. Variance in exposed perturbations impairs retention of visuomotor adaptation.

    Science.gov (United States)

    Canaveral, Cesar Augusto; Danion, Frédéric; Berrigan, Félix; Bernier, Pierre-Michel

    2017-11-01

    Sensorimotor control requires an accurate estimate of the state of the body. The brain optimizes state estimation by combining sensory signals with predictions of the sensory consequences of motor commands using a forward model. Given that both sensory signals and predictions are uncertain (i.e., noisy), the brain optimally weights the relative reliance on each source of information during adaptation. In support, it is known that uncertainty in the sensory predictions influences the rate and generalization of visuomotor adaptation. We investigated whether uncertainty in the sensory predictions affects the retention of a new visuomotor relationship. This was done by exposing three separate groups to a visuomotor rotation whose mean was common at 15° counterclockwise but whose variance around the mean differed (i.e., SD of 0°, 3.2°, or 4.5°). Retention was assessed by measuring the persistence of the adapted behavior in a no-vision phase. Results revealed that mean reach direction late in adaptation was similar across groups, suggesting it depended mainly on the mean of exposed rotations and was robust to differences in variance. However, retention differed across groups, with higher levels of variance being associated with a more rapid reversion toward nonadapted behavior. A control experiment ruled out the possibility that differences in retention were accounted for by differences in success rates. Exposure to variable rotations may have increased the uncertainty in sensory predictions, making the adapted forward model more labile and susceptible to change or decay. NEW & NOTEWORTHY The brain predicts the sensory consequences of motor commands through a forward model. These predictions are subject to uncertainty. We use visuomotor adaptation and modulate uncertainty in the sensory predictions by manipulating the variance in exposed rotations. Results reveal that variance does not influence the final extent of adaptation but selectively impairs the retention of

  2. Estuarine retention of larvae of the crab Rhithropanopeus harrisii

    Science.gov (United States)

    Cronin, Thomas W.

    1982-08-01

    Larvae of estuarine organisms continually face possible export from the parent estuary. Retention of larvae of the estuarine crab Rhithropanopeus harrisii was investigated in the upper Newport River estuary, North Carolina. All of the developmental stages occurred in the same area of the estuary with similar horizontal distributions, and the concentrations of intermediate and late stages were not greatly reduced from those of the first larval stage. This was strong evidence for the continuous retention of larvae in the upper estuary. To determine mechanisms by which retention might be effected, field studies of the vertical distributions and migrations of these larvae were made. The four zoeal stages had similar but complex vertical migration patterns, which varied from study to study. These migrations centered on the depth of no net flow, reducing longitudinal transport during development. Cross-spectral analysis of the larval migrations and the environmental cycles of light, salinity and current speed revealed that each of these external cycles affected larval depth. Megalopae of R. harrisii also migrated vertically, but they were present in much lower concentrations than the zoeal stages, an indication of a change to benthic existence in this final larval form.

  3. An Alfven eigenmode similarity experiment

    International Nuclear Information System (INIS)

    Heidbrink, W W; Fredrickson, E; Gorelenkov, N N; Hyatt, A W; Kramer, G; Luo, Y

    2003-01-01

    The major radius dependence of Alfven mode stability is studied by creating plasmas with similar minor radius, shape, magnetic field (0.5 T), density (n e ≅3x10 19 m -3 ), electron temperature (1.0 keV) and beam ion population (near-tangential 80 keV deuterium injection) on both NSTX and DIII-D. The major radius of NSTX is half the major radius of DIII-D. The super-Alfvenic beam ions that drive the modes have overlapping values of v f /v A in the two devices. Observed beam-driven instabilities include toroidicity-induced Alfven eigenmodes (TAE). The stability threshold for the TAE is similar in the two devices. As expected theoretically, the most unstable toroidal mode number n is larger in DIII-D

  4. Compressional Alfven Eigenmode Similarity Study

    Science.gov (United States)

    Heidbrink, W. W.; Fredrickson, E. D.; Gorelenkov, N. N.; Rhodes, T. L.

    2004-11-01

    NSTX and DIII-D are nearly ideal for Alfven eigenmode (AE) similarity experiments, having similar neutral beams, fast-ion to Alfven speed v_f/v_A, fast-ion pressure, and shape of the plasma, but with a factor of 2 difference in the major radius. Toroidicity-induced AE with ˜100 kHz frequencies were compared in an earlier study [1]; this paper focuses on higher frequency AE with f ˜ 1 MHz. Compressional AE (CAE) on NSTX have a polarization, dependence on the fast-ion distribution function, frequency scaling, and low-frequency limit that are qualitatively consistent with CAE theory [2]. Global AE (GAE) are also observed. On DIII-D, coherent modes in this frequency range are observed during low-field (0.6 T) similarity experiments. Experiments will compare the CAE stability limits on DIII-D with the NSTX stability limits, with the aim of determining if CAE will be excited by alphas in a reactor. Predicted differences in the frequency splitting Δ f between excited modes will also be used. \\vspace0.25em [1] W.W. Heidbrink, et al., Plasmas Phys. Control. Fusion 45, 983 (2003). [2] E.D. Fredrickson, et al., Princeton Plasma Physics Laboratory Report PPPL-3955 (2004).

  5. Prediction of gradient retention data for hydrophilic interaction liquid chromatographic separation of native and fluorescently labeled oligosaccharides.

    Science.gov (United States)

    Vaňková, Nikola; Česla, Petr

    2017-02-17

    In this work, we have investigated the predictive properties of mixed-mode retention model and oligomeric mixed-mode model, taking into account the contribution of monomeric units to the retention, in hydrophilic interaction liquid chromatography. The gradient retention times of native maltooligosaccharides and their fluorescent derivatives were predicted in the oligomeric series with number of monomeric glucose units in the range from two to seven. The maltooligosaccharides were separated on a packed column with carbamoyl-bonded silica stationary phase and 15 gradient profiles with different initial and final mobile phase composition were used with the gradient times 5; 7.5 and 10min. The predicted gradient retention times were compared for calculations based on isocratic retention data and gradient retention data, which provided better accuracy of the results. By comparing two different mobile phase additives, the more accurate retention times were predicted in mobile phases containing ammonium acetate. The acidic derivatives, prepared by reaction of an oligosaccharide with 2-aminobenzoic acid or 8-aminonaphthalene-1,3,6-trisulfonic acid, provided more accurate predictions of the retention data in comparison to native oligosaccharides or their neutral derivatives. The oligomeric mixed-mode model allowed prediction of gradient retention times using only one gradient profile, which significantly speeded-up the method development. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Radionuclide Retention in Concrete Wasteforms

    Energy Technology Data Exchange (ETDEWEB)

    Bovaird, Chase C.; Jansik, Danielle P.; Wellman, Dawn M.; Wood, Marcus I.

    2011-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. The information present in the report provides data that (1) measures the effect of concrete wasteform properties likely to influence radionuclide migration; and (2) quantifies the rate of carbonation of concrete materials in a simulated vadose zone repository.

  7. Breastfeeding reduces postpartum weight retention

    DEFF Research Database (Denmark)

    Baker, Jennifer Lyn; Gamborg, Michael; Heitmann, Berit L

    2008-01-01

    BACKGROUND: Weight gained during pregnancy and not lost postpartum may contribute to obesity in women of childbearing age. OBJECTIVE: We aimed to determine whether breastfeeding reduces postpartum weight retention (PPWR) in a population among which full breastfeeding is common and breastfeeding...... duration is long. DESIGN: We selected women from the Danish National Birth Cohort who ever breastfed (>98%), and we conducted the interviews at 6 (n = 36 030) and 18 (n = 26 846) mo postpartum. We used regression analyses to investigate whether breastfeeding (scored to account for duration and intensity......) reduced PPWR at 6 and 18 mo after adjustment for maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG). RESULTS: GWG was positively (P postpartum. Breastfeeding was negatively associated with PPWR in all women but those...

  8. Implicit memory. Retention without remembering.

    Science.gov (United States)

    Roediger, H L

    1990-09-01

    Explicit measures of human memory, such as recall or recognition, reflect conscious recollection of the past. Implicit tests of retention measure transfer (or priming) from past experience on tasks that do not require conscious recollection of recent experiences for their performance. The article reviews research on the relation between explicit and implicit memory. The evidence points to substantial differences between standard explicit and implicit tests, because many variables create dissociations between these tests. For example, although pictures are remembered better than words on explicit tests, words produce more priming than do pictures on several implicit tests. These dissociations may implicate different memory systems that subserve distinct memorial functions, but the present argument is that many dissociations can be understood by appealing to general principles that apply to both explicit and implicit tests. Phenomena studied under the rubric of implicit memory may have important implications in many other fields, including social cognition, problem solving, and cognitive development.

  9. Separation and retention of iodine

    International Nuclear Information System (INIS)

    Thomas, T.R.

    1976-01-01

    Caustic and mercuric nitrate scrubbers have been used for iodine recovery from process offgas, but they exhibit low decontamination factors for organic iodide removal and produce liquid wastes that are unsuitable for final storage. The Iodox process gives high decontamination factors for both organic iodides and elemental iodine. The liquid waste can be evaporated to a solid or concentrated and fixed in cement. Efficient separation and retention of gaseous iodine species can be obtained with silver-loaded adsorbents. The waste is a dry solid easily handled and stored. Adsorbents containing cheaper metals appear to have lower iodine-loading capacities and may be unsuitable for bulk iodine removal from process offgas because of the large amounts of solid waste that would be generated. A potential method for regenerationg and recycling silver-loaded adsorbents is being evaluated. In conjunction with the regeneration, lead-exchanged zeolite is used as a secondary adsorbent for the final fixation and storage of the iodine

  10. Identifying mechanistic similarities in drug responses

    KAUST Repository

    Zhao, C.

    2012-05-15

    Motivation: In early drug development, it would be beneficial to be able to identify those dynamic patterns of gene response that indicate that drugs targeting a particular gene will be likely or not to elicit the desired response. One approach would be to quantitate the degree of similarity between the responses that cells show when exposed to drugs, so that consistencies in the regulation of cellular response processes that produce success or failure can be more readily identified.Results: We track drug response using fluorescent proteins as transcription activity reporters. Our basic assumption is that drugs inducing very similar alteration in transcriptional regulation will produce similar temporal trajectories on many of the reporter proteins and hence be identified as having similarities in their mechanisms of action (MOA). The main body of this work is devoted to characterizing similarity in temporal trajectories/signals. To do so, we must first identify the key points that determine mechanistic similarity between two drug responses. Directly comparing points on the two signals is unrealistic, as it cannot handle delays and speed variations on the time axis. Hence, to capture the similarities between reporter responses, we develop an alignment algorithm that is robust to noise, time delays and is able to find all the contiguous parts of signals centered about a core alignment (reflecting a core mechanism in drug response). Applying the proposed algorithm to a range of real drug experiments shows that the result agrees well with the prior drug MOA knowledge. © The Author 2012. Published by Oxford University Press. All rights reserved.

  11. Retention in HIV care depends on patients' perceptions of the clinic experience.

    Science.gov (United States)

    Wessinger, Matthew H; Hennink, Monique M; Kaiser, Bonnie N; Mangal, Jed P; Gokhale, Runa H; Ruchin, Lauren; Moanna, Abeer; Rimland, David; Farber, Eugene W; Marconi, Vincent C

    2017-10-01

    Institutional barriers in HIV primary care settings can contribute substantially to disparities in retention in HIV treatment and HIV-related outcomes. This qualitative study compared the perceptions of clinic experiences of persons living with HIV (PLWH) in a Veterans Affairs HIV primary care clinic setting who were retained in care with the experiences of those who were not retained in care. Qualitative data from 25 in-depth interviews were analyzed to identify facilitators and barriers to retention in HIV care. Results showed that participants not retained in care experienced barriers to retention involving dissatisfaction with clinic wait times, low confidence in clinicians, and customer service concerns. For participants retained in care, patience with procedural issues, confidence in clinicians, and interpersonal connections were factors that enhanced retention despite the fact that these participants recognized the same barriers as those who were not retained in care. These findings can inform interventions aimed at improving retention in HIV care.

  12. The contributions of encoding, retention, and recall to the Hebb effect.

    Science.gov (United States)

    Oberauer, Klaus; Meyer, Nadine

    2009-10-01

    The article reports an experiment testing whether the Hebb repetition effect-the gradual improvement of immediate serial recall when the same list is repeated several times-depends on overt recall of the repeated lists. Previous reports which suggest that recall is critical confound the recall manipulation with retention interval. The present experiment orthogonally varies retention interval (0 or 9 s) and whether the list is to be recalled after the retention interval. Hebb repetition learning is assessed in a final test phase. A repetition effect was obtained in all four experimental conditions; it was larger for recalled than non-recalled lists, whereas retention interval had no effect. The results show that encoding is sufficient to generate cumulative long-term learning, which is strengthened by recall. Rehearsal, if it takes place in the retention interval at all, does not have the same effect on long-term learning as overt recall.

  13. Cultural similarity and adjustment of expatriate academics

    DEFF Research Database (Denmark)

    Selmer, Jan; Lauring, Jakob

    2009-01-01

    The findings of a number of recent empirical studies of business expatriates, using different samples and methodologies, seem to support the counter-intuitive proposition that cultural similarity may be as difficult to adjust to as cultural dissimilarity. However, it is not obvious...... and non-EU countries. Results showed that although the perceived cultural similarity between host and home country for the two groups of investigated respondents was different, there was neither any difference in their adjustment nor in the time it took for them to become proficient. Implications...

  14. Protein structural similarity search by Ramachandran codes

    Directory of Open Access Journals (Sweden)

    Chang Chih-Hung

    2007-08-01

    Full Text Available Abstract Background Protein structural data has increased exponentially, such that fast and accurate tools are necessary to access structure similarity search. To improve the search speed, several methods have been designed to reduce three-dimensional protein structures to one-dimensional text strings that are then analyzed by traditional sequence alignment methods; however, the accuracy is usually sacrificed and the speed is still unable to match sequence similarity search tools. Here, we aimed to improve the linear encoding methodology and develop efficient search tools that can rapidly retrieve structural homologs from large protein databases. Results We propose a new linear encoding method, SARST (Structural similarity search Aided by Ramachandran Sequential Transformation. SARST transforms protein structures into text strings through a Ramachandran map organized by nearest-neighbor clustering and uses a regenerative approach to produce substitution matrices. Then, classical sequence similarity search methods can be applied to the structural similarity search. Its accuracy is similar to Combinatorial Extension (CE and works over 243,000 times faster, searching 34,000 proteins in 0.34 sec with a 3.2-GHz CPU. SARST provides statistically meaningful expectation values to assess the retrieved information. It has been implemented into a web service and a stand-alone Java program that is able to run on many different platforms. Conclusion As a database search method, SARST can rapidly distinguish high from low similarities and efficiently retrieve homologous structures. It demonstrates that the easily accessible linear encoding methodology has the potential to serve as a foundation for efficient protein structural similarity search tools. These search tools are supposed applicable to automated and high-throughput functional annotations or predictions for the ever increasing number of published protein structures in this post-genomic era.

  15. 12 CFR 609.945 - Records retention.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Records retention. 609.945 Section 609.945 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM ELECTRONIC COMMERCE Standards for Boards and Management § 609.945 Records retention. Records stored electronically must be accurate, accessible...

  16. Black Student Retention in Higher Education.

    Science.gov (United States)

    Lang, Marvel, Ed.; Ford, Clinita A., Ed.

    This collection focuses on problems in the recruitment, enrollment and retention of Blacks in higher education in America. The following chapters are provided: "The Black Student Retention Problem in Higher Education: Some Introductory Perspectives" (Marvel Lang); "Early Acceptance and Institutional Linkages in a Model Program of Recruitment,…

  17. 76 FR 34010 - Credit Risk Retention

    Science.gov (United States)

    2011-06-10

    ... 2501-AD53 Credit Risk Retention AGENCIES: Office of the Comptroller of the Currency, Treasury (OCC... credit risk retention requirements of section 15G of the Securities Exchange Act of 1934, as added by the Dodd-Frank Wall Street Reform and Consumer Protection Act (``Credit Risk NPR'' or ``proposed rule...

  18. African Retentions in Blues and Jazz.

    Science.gov (United States)

    Meadows, Eddie S.

    1979-01-01

    The perseverance of African musical characteristics among American Blacks is an historic reality. African retentions have been recorded in Black music of the antebellum period. Various African scales and rhythms permeate Black American music today as evidenced in the retentions found in blues and jazz. (RLV)

  19. Emotional Intelligence and Nursing Student Retention

    Science.gov (United States)

    Wilson, Victoria Jane

    2013-01-01

    The study examined the constructs of a Multi-Intelligence Model of Retention with four constructs: cognitive and emotional-social intelligence, student characteristics, and environmental factors. Data were obtained from sophomore students entering two diploma, nine associate, and five baccalaureate nursing programs. One year later, retention and…

  20. A Model for Freshman Engineering Retention

    Science.gov (United States)

    Veenstra, Cindy P.; Dey, Eric L.; Herrin, Gary D.

    2009-01-01

    With the current concern over the growing need for more engineers, there is an immediate need to improve freshman engineering retention. A working model for freshman engineering retention is needed. This paper proposes such a model based on Tinto's Interactionalist Theory. Emphasis in this model is placed on pre-college characteristics as…

  1. Employee Retention Strategies And Organizational Performance ...

    African Journals Online (AJOL)

    Implication of the results for practice is that any organization that fails to put in place adequate employee retention strategies is not likely to retain competent and motivated workforce in its employment and hence experience frequent labour turnover and poor organizational performance. Keywords: Employees, Retention ...

  2. Faculty Personality: A Factor of Student Retention

    Science.gov (United States)

    Shaw, Cassandra S.; Wu, Xiaodong; Irwin, Kathleen C.; Patrizi, L. A. Chad

    2016-01-01

    The purpose of this study was to determine the relationship between student retention and faculty personality as it was hypothesized that faculty personality has an effect on student retention. The methodology adopted for this study was quantitative and in two parts 1) using linear regression models to examine the impact or causality of faculty…

  3. Minority Teacher Recruitment and Retention Strategies

    Science.gov (United States)

    Kearney-Gissendaner, Janet E.

    2010-01-01

    The tools and resources in this book help school leaders seamlessly incorporate minority teacher recruitment and retention programs into current human-resources activities. With details about exemplary minority teacher recruitment and retention programs, this book also showcases strategies for how to replicate such programs in your own school or…

  4. Herpes zoster-induced acute urinary retention.

    Science.gov (United States)

    Addison, Ben; Harvey, Martyn

    2013-06-01

    Urinary retention is a common acute presentation for men in their later decades. Potential contributing pathologies are numerous. We report an unusual case of acute urinary retention requiring catheterisation secondary to sacral herpes zoster reactivation (S2-4) in an 88-year-old man with minimal preceding obstructive symptoms. © 2013 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  5. Effect of Infrared Blanching on Enzyme Activity and Retention of β-Carotene and Vitamin C in Dried Mango.

    Science.gov (United States)

    Guiamba, Isabel R F; Svanberg, Ulf; Ahrné, Lilia

    2015-06-01

    The objectives of this work were to evaluate infrared (IR) dry blanching in comparison with conventional water blanching prior to hot air drying of mango to inactivate polyphenol oxidase (PPO) and ascorbic acid oxidase (AAO) enzymes, and to study its effect on color change and retention of vitamin C and β-carotene. Mango cylinders were blanched under similar temperature-time conditions either by IR heating or by immersion in a water bath during 2 min at 90 °C (high-temperature-short-time-HTST) or for 10 min at 65 °C (low-temperature-long-time-LTLT). After blanching mango was hot air dried at 70 °C. PPO was completely inactivated during the blanching treatments, but AAO had a moderate remaining activity after LTLT treatment (∼30%) and a low remaining activity after HTST treatment (9% to 15%). A higher retention of vitamin C was observed in mango subjected to IR dry blanching, 88.3 ± 1.0% (HTST) and 69.2 ± 2.9% (LTLT), compared with water blanching, 61.4 ± 5.3% (HTST) and 50.7 ± 9.6% (LTLT). All-trans-β-carotene retention was significantly higher in water blanched dried mango, 93.2 ± 5.2% (LTLT) and 91.4 ± 5.1% (HTST), compared with IR dry blanched, 73.6 ± 3.6% (LTLT) and 76.9 ± 2.9% (HTST). Increased levels of 13-cis-β-carotene isomer were detected only in IR dry blanched mango, and the corresponding dried mango also had a slightly darker color. IR blanching of mango prior to drying can improve the retention of vitamin C, but not the retention of carotenoids, which showed to be more dependent on the temperature than the blanching process. A reduction of drying time was observed in LTLT IR-blanching mango. © 2015 Institute of Food Technologists®

  6. Retention of simulated fallout nuclides in agricultural crops. 2. Deposition of Cs and Sr on grain crops

    International Nuclear Information System (INIS)

    Eriksson, Aake; Rosen, K.; Haak, E.

    1998-01-01

    Experiments with artificial wet depositions of 134 Cs and 85 Sr at different times during the growth period were carried out. The studies are complementary to the experiences after the Chernobyl fallout and the results are compared with similar earlier Swedish works on nuclide retention in experiments and on fallout in agriculture. The aim has been to cover the nuclide transfer to grain crops after deposition at different times during the growing period. The initial interception capacity per kg d.w., TRd, seemed to depend on the surface/weight ratio of the plant parts considered. Changes in TRd-values were rapid during the early growth but slower in later stages. The reduction half-time was then often 2 weeks for vegetative parts. Considering the fraction of a deposition retained, FRd, the residence half-time had an average length of 3-4 weeks. During that time there were possibilities for cesium penetration into the plant and further transfer to ears and grain. Strontium did not seem to be transferred that way. There was no increase of cesium in the ears per unit d.w. after the initial interception. However, there was a steady increase in the total content, especially after deposition during the latter half of the growth period when about 5 % was retained of cesium, and 2 % of strontium. The retention of fallout caesium in 1964 was statistically estimated to be of about the same size in Swedish grains

  7. Similarity analysis between quantum images

    Science.gov (United States)

    Zhou, Ri-Gui; Liu, XingAo; Zhu, Changming; Wei, Lai; Zhang, Xiafen; Ian, Hou

    2018-06-01

    Similarity analyses between quantum images are so essential in quantum image processing that it provides fundamental research for the other fields, such as quantum image matching, quantum pattern recognition. In this paper, a quantum scheme based on a novel quantum image representation and quantum amplitude amplification algorithm is proposed. At the end of the paper, three examples and simulation experiments show that the measurement result must be 0 when two images are same, and the measurement result has high probability of being 1 when two images are different.

  8. Similarity flows in relativistic hydrodynamics

    International Nuclear Information System (INIS)

    Blaizot, J.P.; Ollitrault, J.Y.

    1986-01-01

    In ultra-relativistic heavy ion collisions, one expects in particular to observe a deconfinement transition leading to a formation of quark gluon plasma. In the framework of the hydrodynamic model, experimental signatures of such a plasma may be looked for as observable consequences of a first order transition on the evolution of the system. In most of the possible scenario, the phase transition is accompanied with discontinuities in the hydrodynamic flow, such as shock waves. The method presented in this paper has been developed to treat without too much numerical effort such discontinuous flow. It relies heavily on the use of similarity solutions of the hydrodynamic equations

  9. Effect of γ-exposure on retention of recoil 56Mn in permanganates

    International Nuclear Information System (INIS)

    Mishra, S.P.; Vijaya

    2002-01-01

    Full text: γ-exposure effect on recombination of recoil 56 Mn atom in La, Sr and Ba permanganates were studied with a special emphasis to pre-and post-activation γ-ray irradiation treatment using 60 Co source. Permanganates were inactivated by ionizing radiation as a function of γ-dose without neutron irradiation, however, pronounced effects were seen after neutron activation. Pre-irradiation increase the initial retention and promotes the annealing phenomenon as the introduction of defect into the lattice though on the other hand radiolytic phenomenon may also appear. Pre-activated sample gave higher retention value for lanthanum and barium permanganates in comparison to strontium permanganate at different γ-doses for desired period of gamma annealing than those obtained at corresponding γ-doses for similar length of time in case of post-activated targets. Kinetics of annealing by γ-radiolytic effects follow first order rate law. The observed results are discussed in the light of existing ideas for understanding the recoil stabilization phenomenon of parent reformation and the nature of precursors in permanganates

  10. A study on fission product retention capability in a sodium coolant system

    International Nuclear Information System (INIS)

    Satoh, K.; Kubo, S.; Hashiguchi, Y.; Itooka, S.; Akatsu, Y.; Miyagi, K.; Wakamatsu, M.; Endo, H.; Tachino, T.

    1992-01-01

    Three kinds of separate model tests have been performed using water and air, focusing on the transport behavior of FP gas bubbles from subassembly outlets into a cover gas region, to study the dominant processes regarding the retention for volatiles ejected with inert gas into sodium after fuel failures. In the case that whole fuel pin failures occurring coherently in a subassembly were assumed, a periodic formation of globules was observed at the subassembly outlet. The globules rapidly broke up into small bubbles of less than 10 mm in mean diameter. The small bubbles at the top region had a tendency to be coalesced during rising through the upper plenum. As the coolant flow rate increased, bubble deformation and breakup were accelerated, but the bubble transport time did not vary remarkably. It is expected that bubbles in sodium would play in a similar way as in the water test, and the importance of the bubble behavior for the retention capability of volatiles has been confirmed. (author)

  11. Inhalation toxicology of industrial plutonium and uranium oxide aerosols II. Deposition, retention and dosimetry

    International Nuclear Information System (INIS)

    Stanley, J.A.; Eidson, A.F.; Mewhinney, J.A.; Mo, T.

    1978-01-01

    A series of studies has been initiated in which powdered fuel materials obtained at industrial sites have been aerosolized in the dry state for the inhalation exposure of Fischer-344 rats, Beagle dogs and Cynomolgus monkeys to evaluate the potential biological hazard of such accidents. The materials chosen for study were 750 deg. C heat-treated mixed PuO 2 and UO 2 obtained from a ball milling process and 1750 deg. C heat-treated (U,Pu)O 1.97 powder obtained from the centerless grinding of fuel pellets. Care was taken to insure that the regenerated aerosols used in animal inhalation exposures had similar particle size and size distribution characteristics to those measured during glove box sampling at the industrial plant. The deposition, retention, distribution and excretion of these materials are being studied, using serial sacrifice of animals at times from 4 hours to several years after inhalation exposure. Periodic excreta samples are collected on all animals. Biological samples are analyzed to yield data on Pu, Am and U content. Data from animals sacrificed up to one year will be presented. The retention of 239 Pu and 241 Am in the lung and their subsequent clearance and translocation to other tissues such as liver, skeleton and tracheobronchial lymph nodes will be discussed in relation to the influence of species and of the physical chemical properties of the exposure aerosol. (author)

  12. Stellar Wind Retention and Expulsion in Massive Star Clusters

    Science.gov (United States)

    Naiman, J. P.; Ramirez-Ruiz, E.; Lin, D. N. C.

    2018-05-01

    Mass and energy injection throughout the lifetime of a star cluster contributes to the gas reservoir available for subsequent episodes of star formation and the feedback energy budget responsible for ejecting material from the cluster. In addition, mass processed in stellar interiors and ejected as winds has the potential to augment the abundance ratios of currently forming stars, or stars which form at a later time from a retained gas reservoir. Here we present hydrodynamical simulations that explore a wide range of cluster masses, compactnesses, metallicities and stellar population age combinations in order to determine the range of parameter space conducive to stellar wind retention or wind powered gas expulsion in star clusters. We discuss the effects of the stellar wind prescription on retention and expulsion effectiveness, using MESA stellar evolutionary models as a test bed for exploring how the amounts of wind retention/expulsion depend upon the amount of mixing between the winds from stars of different masses and ages. We conclude by summarizing some implications for gas retention and expulsion in a variety of compact (σv ≳ 20 kms-1) star clusters including young massive star clusters (105 ≲ M/M⊙ ≲ 107, age ≲ 500 Myrs), intermediate age clusters (105 ≲ M/M⊙ ≲ 107, age ≈ 1 - 4 Gyrs), and globular clusters (105 ≲ M/M⊙ ≲ 107, age ≳ 10 Gyrs).

  13. Novel word retention in sequential bilingual children.

    Science.gov (United States)

    Kan, Pui Fong

    2014-03-01

    Children's ability to learn and retain new words is fundamental to their vocabulary development. This study examined word retention in children learning a home language (L1) from birth and a second language (L2) in preschool settings. Participants were presented with sixteen novel words in L1 and in L2 and were tested for retention after either a 2-month or a 4-month delay. Results showed that children retained more words in L1 than in L2 for both of the retention interval conditions. In addition, children's word retention was associated with their existing language knowledge and their fast-mapping performance within and across language. The patterns of association, however, were different between L1 and L2. These findings suggest that children's word retention might be related to the interactions of various components that are operating within a dynamic system.

  14. Self-similar gravitational clustering

    International Nuclear Information System (INIS)

    Efstathiou, G.; Fall, S.M.; Hogan, C.

    1979-01-01

    The evolution of gravitational clustering is considered and several new scaling relations are derived for the multiplicity function. These include generalizations of the Press-Schechter theory to different densities and cosmological parameters. The theory is then tested against multiplicity function and correlation function estimates for a series of 1000-body experiments. The results are consistent with the theory and show some dependence on initial conditions and cosmological density parameter. The statistical significance of the results, however, is fairly low because of several small number effects in the experiments. There is no evidence for a non-linear bootstrap effect or a dependence of the multiplicity function on the internal dynamics of condensed groups. Empirical estimates of the multiplicity function by Gott and Turner have a feature near the characteristic luminosity predicted by the theory. The scaling relations allow the inference from estimates of the galaxy luminosity function that galaxies must have suffered considerable dissipation if they originally formed from a self-similar hierarchy. A method is also developed for relating the multiplicity function to similar measures of clustering, such as those of Bhavsar, for the distribution of galaxies on the sky. These are shown to depend on the luminosity function in a complicated way. (author)

  15. Personnel Retention Policy and Force Quality: Twice-Passed Staff Sergeants

    Science.gov (United States)

    2015-06-01

    61 Figure 20. Impact of Policy Changes on Average TIG . For Staff Sergeants, average TIG is reduced from 4.4 years to 3.8 years...with a 2P non-retention policy. Sergeants (E5) experience the only other significant reduction in average TIG , which goes from 3.2 years in the base...Warehouse TFRS Total Force Retention System TIG Time in Grade TIS Time in Service VSP Voluntary Separations Pay xxiii EXECUTIVE SUMMARY In

  16. Universal self-similarity of propagating populations.

    Science.gov (United States)

    Eliazar, Iddo; Klafter, Joseph

    2010-07-01

    This paper explores the universal self-similarity of propagating populations. The following general propagation model is considered: particles are randomly emitted from the origin of a d-dimensional Euclidean space and propagate randomly and independently of each other in space; all particles share a statistically common--yet arbitrary--motion pattern; each particle has its own random propagation parameters--emission epoch, motion frequency, and motion amplitude. The universally self-similar statistics of the particles' displacements and first passage times (FPTs) are analyzed: statistics which are invariant with respect to the details of the displacement and FPT measurements and with respect to the particles' underlying motion pattern. Analysis concludes that the universally self-similar statistics are governed by Poisson processes with power-law intensities and by the Fréchet and Weibull extreme-value laws.

  17. Universal self-similarity of propagating populations

    Science.gov (United States)

    Eliazar, Iddo; Klafter, Joseph

    2010-07-01

    This paper explores the universal self-similarity of propagating populations. The following general propagation model is considered: particles are randomly emitted from the origin of a d -dimensional Euclidean space and propagate randomly and independently of each other in space; all particles share a statistically common—yet arbitrary—motion pattern; each particle has its own random propagation parameters—emission epoch, motion frequency, and motion amplitude. The universally self-similar statistics of the particles’ displacements and first passage times (FPTs) are analyzed: statistics which are invariant with respect to the details of the displacement and FPT measurements and with respect to the particles’ underlying motion pattern. Analysis concludes that the universally self-similar statistics are governed by Poisson processes with power-law intensities and by the Fréchet and Weibull extreme-value laws.

  18. Time Searching for Similar Binary Vectors in Associative Memory

    Czech Academy of Sciences Publication Activity Database

    Frolov, A. A.; Húsek, Dušan; Rachkovskij, D.

    2006-01-01

    Roč. 42, č. 5 (2006), s. 615-623 ISSN 1060-0396 R&D Projects: GA MŠk(CZ) 1M0567 Institutional research plan: CEZ:AV0Z10300504 Keywords : associative memory * neural network * Hopfield network * binary vector * indexing * hashing Subject RIV: BB - Applied Statistics, Operational Research

  19. Effect of gavaged chemical form of 241Am on its retention in mice

    International Nuclear Information System (INIS)

    Hisamatsu, S.; Takizawa, Y.

    1987-01-01

    The retention of 241 Am in mice 48 h after administration by gavage is reported here. The 241 Am was given to mice in the form of either 241 Am nitrate or 241 Am citrate. The 241 Am was also injected into rats in the same form. The homogenized livers of those rats were subsequently administered by gavage to another group of mice. The retention of 241 Am citrate was 1.5 X 10(-2)% of the original dose and was the highest among the compounds examined. The retention of biologically incorporated 241 Am into the liver as 241 Am nitrate and as 241 Am citrate was 2.4 X 10(-3) and 2.6 X 10(-3)%, respectively, and was similar to the retention of 241 Am nitrate, which was 2.8 X 10(-3)%. The ratio of the retention in the carcass to that in the liver for the 241 Am citrate was lower than that of the 241 Am nitrate and the biologically incorporated 241 Am. This difference indicates that the distribution of 241 Am in the animal body depends on the chemical form administered. The retention of liver-incorporated 241 Am as citrate after autolysis of the liver is similar to that of fresh liver-incorporated 241 Am citrate

  20. Effect of ceramic membrane channel diameter on limiting retentate protein concentration during skim milk microfiltration.

    Science.gov (United States)

    Adams, Michael C; Barbano, David M

    2016-01-01

    Our objective was to determine the effect of retentate flow channel diameter (4 or 6mm) of nongraded permeability 100-nm pore size ceramic membranes operated in nonuniform transmembrane pressure mode on the limiting retentate protein concentration (LRPC) while microfiltering (MF) skim milk at a temperature of 50°C, a flux of 55 kg · m(-2) · h(-1), and an average cross-flow velocity of 7 m · s(-1). At the above conditions, the retentate true protein concentration was incrementally increased from 7 to 11.5%. When temperature, flux, and average cross-flow velocity were controlled, ceramic membrane retentate flow channel diameter did not affect the LRPC. This indicates that LRPC is not a function of the Reynolds number. Computational fluid dynamics data, which indicated that both membranes had similar radial velocity profiles within their retentate flow channels, supported this finding. Membranes with 6-mm flow channels can be operated at a lower pressure decrease from membrane inlet to membrane outlet (ΔP) or at a higher cross-flow velocity, depending on which is controlled, than membranes with 4-mm flow channels. This implies that 6-mm membranes could achieve a higher LRPC than 4-mm membranes at the same ΔP due to an increase in cross-flow velocity. In theory, the higher LRPC of the 6-mm membranes could facilitate 95% serum protein removal in 2 MF stages with diafiltration between stages if no serum protein were rejected by the membrane. At the same flux, retentate protein concentration, and average cross-flow velocity, 4-mm membranes require 21% more energy to remove a given amount of permeate than 6-mm membranes, despite the lower surface area of the 6-mm membranes. Equations to predict skim milk MF retentate viscosity as a function of protein concentration and temperature are provided. Retentate viscosity, retentate recirculation pump frequency required to maintain a given cross-flow velocity at a given retentate viscosity, and retentate protein