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…

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.

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.

Teacher professionalisation in relation to retention strategies

DEFF Research Database (Denmark)

Mariager-Anderson, Kristina; Wahlgren, Bjarne

pedagogical strategies have any impact on retention? The project started in 2010 and includes annual interventions and measurements of the output of these inventions. The intervention includes various teacher training programs e.g. about training in cooperative learning, classroom management, conflict......Teacher professionalization in relation to retention strategies Bjarne Wahlgren, professor, director National Centre of Competence Development, University of Aarhus, Denmark The research project ‘New roles for the teacher’ was initiated due to a concern about the increasing number of dropouts...... within Danish VET. The main research questions are: Is it possible to train teachers to be able to focus on the students’ completion of the program and not only on the subject matter? Do teachers change their attitudes and actual performance in the classroom after training programs? And do new...

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.

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

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…

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

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.

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.

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

Using a retention in care protocol to promote positive health and systems related outcomes.

Science.gov (United States)

Larbi, Alfred A; Spielberg, Freya; Kamanu Elias, Nnemdi; Athey, Erin; Ogbuawa, Ngozi; Murphy, Nancy

2018-04-18

People living with HIV can experience the full benefits of retention when they are continuously engaged in care. Continuous engagement in care promotes improved adherence to ART and positive health outcomes. An infectious disease clinic has implemented a protocol to primarily improve patient retention. The retrospective, facility-based, costing study took place in an infectious disease clinic in Washington DC. Retention was defined in two ways and over a 12-month period. Micro-costing direct measurement methods were used to collect unit costs in time series. Return on investment accounted for the cost of treatment based on CD4 strata. ROI was expressed in 2016USD. The difference in CD4 and viral load levels between the two periods of analysis were determined for active patients, infected with HIV. The year before the intervention was compared to the year of the intervention. Total treatment expenditure decreased from $2,435,653.00 to $2,283,296.23, resulting in a $152,356.77 gain from investment for the healthcare system over a 12-month investment period. The viral load suppression rate increased from 81 to 95 (p = 0.04) over the investment period. The number of patients in need of HIV related opportunistic infection prophylaxis decreased from 21 to 13 (p = 0.06). Improved immunologic, virologic and healthcare expenditure outcomes can be linked to the quality of retention practice.

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.)

Improving subject recruitment, retention, and participation in research through Peplau's theory of interpersonal relations.

Science.gov (United States)

Penckofer, Sue; Byrn, Mary; Mumby, Patricia; Ferrans, Carol Estwing

2011-04-01

Recruitment and retention of persons participating in research is one of the most significant challenges faced by investigators. Although incentives are often used to improve recruitment and retention, evidence suggests that the relationship of the patient to study personnel may be the single, most important factor in subject accrual and continued participation. Peplau's theory of interpersonal relations provides a framework to study the nurse-patient relationship during the research process. In this paper the authors provide a brief summary of research strategies that have been used for the recruitment and retention of subjects and an overview of Peplau's theory of interpersonal relations including its use in research studies. In addition, a discussion of how this theory was used for the successful recruitment and retention of women with type 2 diabetes who participated in a clinical trial using a nurse-delivered psychoeducational intervention for depression is addressed.

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.

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

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.

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.

[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

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

Retention of Mastoidectomy Skills After Virtual Reality Simulation Training.

Science.gov (United States)

Andersen, Steven Arild Wuyts; Konge, Lars; Cayé-Thomasen, Per; Sørensen, Mads Sølvsten

2016-07-01

pretraining relative reaction time, 1.42 [95% CI, 1.37-1.47]; mean end of training relative reaction time, 1.24 [95% CI, 1.16-1.32]; and mean retention relative reaction time, 1.36 [95% CI, 1.30-1.42]; massed practice group: mean pretraining relative reaction time, 1.34 [95% CI, 1.28-1.40]; mean end of training relative reaction time, 1.31 [95% CI, 1.21-1.42]; and mean retention relative reaction time, 1.39 [95% CI, 1.31-1.46]) indicated that cognitive load during the virtual procedures had returned to the pretraining level. Mastoidectomy skills acquired under time-distributed practice conditions were retained better than skills acquired under massed practice conditions. Complex psychomotor skills should be regularly reinforced to consolidate both motor and cognitive aspects. Virtual reality simulation training provides the opportunity for such repeated training and should be integrated into training curricula.

How Tenure in Higher Education Relates to Faculty Productivity and Retention

Science.gov (United States)

Manjounes, Cindy Kay

2016-01-01

Some public university systems are considering abolishing tenure as a cost-saving mechanism, but little is known about how this change may impact organizational outcomes related to faculty retention and research productivity. Using Almendarez' human capital theory, the purpose of this concurrent mixed methods study was to explore how tenure…

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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…

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…

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.

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.

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.

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...

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.

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

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…

Exploring the socio-demographic differences on psychological career meta-capacities and retention-related dispositions

Directory of Open Access Journals (Sweden)

Rebecca Tladinyane

2015-08-01

Full Text Available The aim of this study was to better understand socio-demographic differences of individuals in terms of their psychological career meta-capacities (measured by the Psychological Career Resources Inventory and their retention related dispositions construct variables ((measured by the Utrecht Work Engagement Scale and Organisation-Related Commitment Scale. A quantitative survey was conducted involving a non-probability purposive sample of predominantly black females employed at managerial and staff levels (N = 318 in the field of industrial and organisational psychology. An independent-samples t-test indicated significant differences between the various socio-demographic groups in regard to the measured variables. The findings contribute new knowledge that may be used to inform human resource career development practices concerned with the retention of particularly female employees in South African service industry

77 FR 3745 - Establishment of a One-Year Retention Period for Trademark-Related Papers That Have Been Scanned...

Science.gov (United States)

2012-01-25

... to the USPTO's past practice of indefinitely retaining papers that have been scanned into TICRS stems... One-Year Retention Period for Trademark- Related Papers That Have Been Scanned Into the Trademark... retention period that began on September 26, 2011, for papers scanned into the Trademark Initial Capture...

Principles of Precision Prevention Science for Improving Recruitment and Retention of Participants.

Science.gov (United States)

Supplee, Lauren H; Parekh, Jenita; Johnson, Makedah

2018-03-12

Precision medicine and precision public health focus on identifying and providing the right intervention to the right population at the right time. Expanding on the concept, precision prevention science could allow the field to examine prevention programs to identify ways to make them more efficient and effective at scale, including addressing issues related to engagement and retention of participants. Research to date on engagement and retention has often focused on demographics and risk factors. The current paper proposes using McCurdy and Daro (Family Relations, 50, 113-121, 2001) model that posits a complex mixture of individual, provider, program, and community-level factors synergistically affect enrollment, engagement, and retention. The paper concludes recommending the use of research-practice partnerships and innovative, rapid cycle methods to design and improve prevention programs related to participant engagement and retention at scale.

Patient-centered recruitment and retention for a randomized controlled study.

Science.gov (United States)

Chhatre, Sumedha; Jefferson, Ashlie; Cook, Ratna; Meeker, Caitlin R; Kim, Ji Hyun; Hartz, Kayla Marie; Wong, Yu-Ning; Caruso, Adele; Newman, Diane K; Morales, Knashawn H; Jayadevappa, Ravishankar

2018-03-27

Recruitment and retention strategies for patient-centered outcomes research are evolving and research on the subject is limited. In this work, we present a conceptual model of patient-centered recruitment and retention, and describe the recruitment and retention activities and related challenges in a patient-centered comparative effectiveness trial. This is a multicenter, longitudinal randomized controlled trial in localized prostate cancer patients. We recruited 743 participants from three sites over 15 months period (January 2014 to March 2015), and followed them for 24 months. At site 1, of the 773 eligible participants, 551 (72%) were enrolled. At site 2, 34 participants were eligible and 23 (68%) enrolled. Of the 434 eligible participants at site 3, 169 (39%) enrolled. We observed that strategies related to the concepts of trust (e.g., physician involvement, ensuring protection of information), communication (e.g., brochures and pamphlets in physicians' offices, continued contact during regular clinic visits and calling/emailing assessment), attitude (e.g., emphasizing the altruistic value of research, positive attitude of providers and research staff), and expectations (e.g., full disclosure of study requirements and time commitment, update letters) facilitated successful patient recruitment and retention. A stakeholders' advisory board provided important input for the recruitment and retention activities. Active engagement, reminders at the offices, and personalized update letters helped retention during follow-up. Usefulness of telephone recruitment was site specific and, at one site, the time requirement for telephone recruitment was a challenge. We have presented multilevel strategies for successful recruitment and retention in a clinical trial using a patient-centered approach. Our strategies were flexible to accommodate site-level requirements. These strategies as well as the challenges can aid recruitment and retention efforts of future large

Recruitment and retention of young women into nutrition research studies: practical considerations.

Science.gov (United States)

Leonard, Alecia; Hutchesson, Melinda; Patterson, Amanda; Chalmers, Kerry; Collins, Clare

2014-01-16

Successful recruitment and retention of participants into research studies is critical for optimising internal and external validity. Research into diet and lifestyle of young women is important due to the physiological transitions experienced at this life stage. This paper aims to evaluate data related to recruitment and retention across three research studies with young women, and present practical advice related to recruiting and retaining young women in order to optimise study quality within nutrition research. Recruitment and retention strategies used in three nutrition studies that targeted young women (18 to 35 years) were critiqued. A randomised controlled trial (RCT), a crossover validation study and a cross-sectional survey were conducted at the University of Newcastle, Australia between 2010 and 2013Successful recruitment was defined as maximum recruitment relative to time. Retention was assessed as maximum participants remaining enrolled at study completion. Recruitment approaches included notice boards, web and social network sites (Facebook and Twitter), with social media most successful in recruitment. The online survey had the highest recruitment in the shortest time-frame (751 participants in one month). Email, phone and text message were used in study one (RCT) and study two (crossover validation) and assisted in low attrition rates, with 93% and 75.7% completing the RCT and crossover validation study respectively. Of those who did not complete the RCT, reported reasons were: being too busy; and having an unrelated illness. Recruiting young women into nutrition research is challenging. Use of social media enhances recruitment, while Email, phone and text message contact improves retention within interventions. Further research comparing strategies to optimise recruitment and retention in young women, including flexible testing times, reminders and incentives is warranted.

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)

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

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)

Examining the Relations among Student Motivation, Engagement, and Retention in a MOOC: A Structural Equation Modeling Approach

Directory of Open Access Journals (Sweden)

Yao Xiong

2015-09-01

Full Text Available Students who are enrolled in MOOCs tend to have different motivational patterns than fee-paying college students. A majority of MOOC students demonstrate characteristics akin more to "tourists" than formal learners. As a consequence, MOOC students’ completion rate is usually very low. The current study examines the relations among student motivation, engagement, and retention using structural equation modeling and data from a Penn State University MOOC. Three distinct types of motivation are examined: intrinsic motivation, extrinsic motivation, and social motivation. Two main hypotheses are tested: (a motivation predicts student course engagement; and (b student engagement predicts their retention in the course. The results show that motivation is significantly predictive of student course engagement. Furthermore, engagement is a strong predictor of retention. The findings suggest that promoting student motivation and monitoring individual students’ online activities might improve course retention

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.

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.

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

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.

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.

Causal modeling of self-concept, job satisfaction, and retention of nurses.

Science.gov (United States)

Cowin, Leanne S; Johnson, Maree; Craven, Rhonda G; Marsh, Herbert W

2008-10-01

The critical shortage of nurses experienced throughout the western world has prompted researchers to examine one major component of this complex problem - the impact of nurses' professional identity and job satisfaction on retention. A descriptive correlational design with a longitudinal element was used to examine a causal model of nurses' self-concept, job satisfaction, and retention plans in 2002. A random sample of 2000 registered nurses was selected from the state registering authority listing. A postal survey assessing multiple dimensions of nurses' self-concept (measured by the nurse self-concept questionnaire), job satisfaction (measured by the index of work satisfaction) was undertaken at Time 1 (n=528) and 8 months later at Time 2 (n=332) (including retention plans (measured by the Nurse Retention Index). Using confirmatory factor analysis, correlation matrices and path analysis, measurement and structural models were examined on matching pairs of data from T1 and T2 (total sample N=332). Nurses' self-concept was found to have a stronger association with nurses' retention plans (B=.45) than job satisfaction (B=.28). Aspects of pay and task were not significantly related to retention plans, however, professional status (r=.51), and to a lesser extent, organizational policies (r=.27) were significant factors. Nurses' general self-concept was strongly related (r=.57) to retention plans. Strategies or interventions requiring implementation and evaluation include: counseling to improve nurse general self-concept, education programs and competencies in health communication between health professionals, reporting of nurse-initiated programs with substantial patient benefit, nurse-friendly organizational policies, common health team learning opportunities, and autonomous practice models.

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.

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

The effect of 2,3-dimercaptopropane sodium sulfonate on mercury retention in rats in relation to age

International Nuclear Information System (INIS)

Kostial, K.; Kargacin, B.; Blanusa, M.; Landeka, M.

1984-01-01

The effectiveness of DMPS (sodium 2,3-dimercaptopropane-l-sulfonate) in reducing inorganic mercury retention was studied in 2-, 6-, and 28-week-old albino rats. 203 Hg was administered IP. The chelating agent DMPS was administered by injection at a dose of 250 μmol/kg body weight three times, 1 day after 203 Hg administration and at 24 h intervals thereafter. The whole body retention determined 1, 2, 3, and 6 days after 203 Hg administration showed that DMPS decreased the body retention of mercury in all age groups, being about twice as effective in adult compared to suckling rats. The reduced effectiveness was due to the reduced efficacy of DMPS in reducing kidney retention in young animals. In other organs the effectiveness of DMPS was not age dependent. These and previous results obtained with different chelating agents and other metals indicate that age might be an important factor in chelation therapy in general. (orig.)

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).

Retention predictors related to intensive outpatient programs for substance use disorders.

Science.gov (United States)

Veach, L J; Remley, T P; Kippers, S M; Sorg, J D

2000-08-01

The purpose of this research was to expand knowledge in the current literature regarding treatment retention in intensive outpatient substance abuse treatment programs. The sample in this study participated in a hospital-based program accredited by the Joint Commission on Accreditation for Health Organizations (JCAHO) that utilized the Minnesota model. Specifically, this inquiry investigated whether treatment retention would be predicted by gender, age, employment status, number of problems on the treatment plan, whether the referral was related to driving while intoxicated (DWI), marital status, race, and whether each of the following substance problems was listed as the client's primary DSM-IV diagnosis: alcohol dependence, cocaine dependence, polysubstance dependence, opioid dependence, sedative/hypnotic dependence, cannabis dependence, other (or unknown) dependence, alcohol abuse, cannabis abuse, amphetamine abuse, and caffeine intoxication. Findings indicated that those retained in treatment, when compared to those who dropped out, had significantly more problems on their treatment plans, were more likely to be alcoholics, were less often cocaine addicts, and were more likely to be employed. The results of this study suggest that clients with this profile have increased likelihood of being retained in intensive outpatient substance abuse treatment programs.

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.

Stability of orthodontic treatment outcome in relation to retention status: An 8-year follow-up.

Science.gov (United States)

Steinnes, Jeanett; Johnsen, Gunn; Kerosuo, Heidi

2017-06-01

Our aim was to evaluate the stability of orthodontic treatment outcome and retention status 7 or more years after active treatment in relation to posttreatment or postretention time, type of retention appliance, and duration of retainer use. The subjects were former patients who completed orthodontic treatment with fixed appliances from 2000 to 2007. The pretreatment eligibility criteria were anterior crowding of 4 mm or more in the maxilla or the mandible and Angle Class I or Class II sagittal molar relationship. Acceptable pretreatment and posttreatment dental casts were required. A total of 67 patients participated, 24 men and 43 women, with a mean age of 24.7 years (range, 20.0-50.0 years). All participants had a follow-up clinical examination, which included impressions for follow-up casts, and each completed a questionnaire. Data were obtained from pretreatment, posttreatment, and follow-up (T2) casts as well as from the patients' dental records. Treatment stability was evaluated with the peer assessment rating (PAR) index and Little's irregularity index. The participation rate was 64%. The average posttreatment time was 8.5 years (range, 7.0-11.0). All participants had received a retainer in the mandible, maxilla, or both after active treatment. At T2, the PAR score showed a mean relapse of 14%. The majority (78%) of participants still had a fixed retainer at T2 (retainer group), and 22% had been out of retention for at least 1 year (postretention group). The relapse according to the PAR did not differ significantly between participants with and without a retainer at T2. From posttreatment to T2, the irregularity of the mandibular incisors increased almost 3 times more in participants with no retainer in the mandible compared with those with an intact retainer at T2 (P = 0.001). In the maxilla, no corresponding difference was found. Our results suggest that occlusal relapse can be expected after active orthodontic treatment irrespective of long

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

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....

On the relation between motivation and retention in educational contexts: The role of intentional and unintentional mind wandering.

Science.gov (United States)

Seli, Paul; Wammes, Jeffrey D; Risko, Evan F; Smilek, Daniel

2016-08-01

Highly motivated students often exhibit better academic performance than less motivated students. However, to date, the specific cognitive mechanisms through which motivation increases academic achievement are not well understood. Here we explored the possibility that mind wandering mediates the relation between motivation and academic performance, and additionally, we examined possible mediation by both intentional and unintentional forms of mind wandering. We found that participants reporting higher motivation to learn in a lecture-based setting tended to engage in less mind wandering, and that this decrease in mind wandering was in turn associated with greater retention of the lecture material. Critically, we also found that the influence of motivation on retention was mediated by both intentional and unintentional types of mind wandering. Not only do the present results advance our theoretical understanding of the mechanisms underlying the relation between motivation and academic achievement, they also provide insights into possible methods of intervention that may be useful in improving student retention in educational settings.

A biologically relevant method for considering patterns of oceanic retention in the Southern Ocean

Science.gov (United States)

Mori, Mao; Corney, Stuart P.; Melbourne-Thomas, Jessica; Klocker, Andreas; Sumner, Michael; Constable, Andrew

2017-12-01

Many marine species have planktonic forms - either during a larval stage or throughout their lifecycle - that move passively or are strongly influenced by ocean currents. Understanding these patterns of movement is important for informing marine ecosystem management and for understanding ecological processes generally. Retention of biological particles in a particular area due to ocean currents has received less attention than transport pathways, particularly for the Southern Ocean. We present a method for modelling retention time, based on the half-life for particles in a particular region, that is relevant for biological processes. This method uses geostrophic velocities at the ocean surface, derived from 23 years of satellite altimetry data (1993-2016), to simulate the advection of passive particles during the Southern Hemisphere summer season (from December to March). We assess spatial patterns in the retention time of passive particles and evaluate the processes affecting these patterns for the Indian sector of the Southern Ocean. Our results indicate that the distribution of retention time is related to bathymetric features and the resulting ocean dynamics. Our analysis also reveals a moderate level of consistency between spatial patterns of retention time and observations of Antarctic krill (Euphausia superba) distribution.

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.

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.

Adaptive memory: young children show enhanced retention of fitness-related information.

Science.gov (United States)

Aslan, Alp; Bäuml, Karl-Heinz T

2012-01-01

Evolutionary psychologists propose that human cognition evolved through natural selection to solve adaptive problems related to survival and reproduction, with its ultimate function being the enhancement of reproductive fitness. Following this proposal and the evolutionary-developmental view that ancestral selection pressures operated not only on reproductive adults, but also on pre-reproductive children, the present study examined whether young children show superior memory for information that is processed in terms of its survival value. In two experiments, we found such survival processing to enhance retention in 4- to 10-year-old children, relative to various control conditions that also required deep, meaningful processing but were not related to survival. These results suggest that, already in very young children, survival processing is a special and extraordinarily effective form of memory encoding. The results support the functional-evolutionary proposal that young children's memory is "tuned" to process and retain fitness-related information. Copyright © 2011 Elsevier B.V. All rights reserved.

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)

Short-term Retention of Relational Memory in Amnesia Revisited: Accurate Performance Depends on Hippocampal Integrity

Directory of Open Access Journals (Sweden)

Lydia T.S. Yee

2014-01-01

Full Text Available Traditionally, it has been proposed that the hippocampus and adjacent medial temporal lobe cortical structures are selectively critical for long-term declarative memory, which entails memory for inter-item and item-context relationships. Whether the hippocampus might also contribute to short-term retention of relational memory representations has remained controversial. In two experiments, we revisit this question by testing memory for relationships among items embedded in scenes using a standard working memory trial structure in which a sample stimulus is followed by a brief delay and the corresponding test stimulus. In each experimental block, eight trials using different exemplars of the same scene were presented. The exemplars contained the same items but with different spatial relationships among them. By repeating the pictures across trials, any potential contributions of item or scene memory to performance were minimized, and relational memory could be assessed more directly than has been done previously. When test displays were presented, participants indicated whether any of the item-location relationships had changed. Then, regardless of their responses (and whether any item did change its location, participants indicated on a forced-choice test, which item might have moved, guessing if necessary. Amnesic patients were impaired on the change detection test, and were frequently unable to specify the change after having reported correctly that a change had taken place. Comparison participants, by contrast, frequently identified the change even when they failed to report the mismatch, an outcome that speaks to the sensitivity of the change specification measure. These results confirm past reports of hippocampal contributions to short-term retention of relational memory representations, and suggest that the role of the hippocampus in memory has more to do with relational memory requirements than the length of a retention interval.

Validating Student Satisfaction Related to Persistence, Academic Performance, Retention and Career Advancement within ODL Perspectives

Science.gov (United States)

Sembiring, Maximus Gorky

2015-01-01

Student satisfaction associated with persistence, academic performance, retention, and its relations to career advancement were examined. It was aimed at measuring service quality (Servqual) dimensions as a foundation of satisfaction and how, in what comportments, they were interrelated. The study was conducted under explanatory-design. Data was…

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.

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)

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...

Consideration of age-dependent radium retention in people on the basis of the beagle model

International Nuclear Information System (INIS)

Parks, N.J.; Keane, A.T.

1981-01-01

This paper examines in humans the proposition emanating from studies in beagles that long-term retention of radium varies in proportion to the calcium addition rate at the time of intake. Because data on the calcium addition rate in younger humans were fragmentary, human calcium-addition rates were scaled from those in beagles, the relative calcium accretion rates in the two species at equivalent stages of skeletal growth providing the scaling factor. The variation of radium retention with age was determined by fitting a modified power function to data on the retention of radium from about 30 to 15,000 days following a series of therapeutic injections of 226 Ra in humans ranging in age from 18 to 63 yr. The fractional retention R at t days following a single injection of 226 Ra was described by R = (1 + t/d) - 0 44 . The age-dependent time constant d in the retention function was found to be proportional to the calcium addition rate at the time of injection in subjects receiving 226 Ra

The effect of extensive reading and paired-associate learning on long-term vocabulary retention: an event-related potential study.

Science.gov (United States)

Chun, Eunjin; Choi, Sungmook; Kim, Junsoo

2012-07-19

We investigated the relative efficacy of extensive reading (ER) and paired-associate learning (PAL) in the ability of second language (L2) learners to retain new vocabulary words. To that end, we combined behavioral measures (i.e., vocabulary tests) and an event-related potential (ERP) investigation with a focus on the N400 ERP component to track short- and long-term vocabulary retention as a consequence of the two different approaches. Behavioral results indicated that both ER and PAL led to substantial short-term retention of the target words. In contrast, on a long-term basis, ER was more effective than PAL to a considerable degree as indicated by a large-size effect (d=1.35). Evidence from the N400 effects (d=1.70) observed in the parietal electrode group (P3, Pz, P4) provided further support for the superior effects of ER over PAL on long-term vocabulary retention. The converging evidence challenges the assumptions of some L2 researchers and makes a significant contribution to the literature of vocabulary acquisition, because it provides the first ERP evidence that ER is more conducive to long-term vocabulary retention than PAL. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

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

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

Retention factors in relation to organisational commitment in medical and information technology services

Directory of Open Access Journals (Sweden)

Jeannette van Dyk

2012-07-01

Research purpose: The objectives of the study were to investigate empirically: (1 the relationship between employees’ satisfaction with organisational retention factors (measured by the Retention Factors Scale and their organisational commitment (measured by the Organisational Commitment Questionnaire and (2 whether gender, age, race and tenure groups differ significantly in terms of these variables. Motivation for the study: Medical and information technology professionals have specialised and hard to replace skills. They also have strong tendencies to leave their organisations and countries. Understanding the retention factors that will increase their organisational commitment may benefit the organisations who want to retain their valuable talent. Research design, approach and method: The researchers used a cross-sectional survey design to collect data from a purposive sample of 206 staff members who had scarce skills in a South African medical and information technology services company. Correlational and inferential statistics were computed to achieve the objectives. Main findings: The results showed that the participants’ satisfaction with retention factors has a significant relationship with their organisational commitment and that the biographical groups differ significantly in terms of the variables. Practical/managerial implications: The measured retention factors were all associated with human resource management practices that influence employees’ intentions to leave. Contribution/value-add: The results are important to managers who are interested in retaining staff who have scarce skills and provide valuable pointers for designing effective retention strategies.

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.

A theoretical model of job retention for home health care nurses.

Science.gov (United States)

Ellenbecker, Carol Hall

2004-08-01

Predicted severe nursing shortages and an increasing demand for home health care services have made the retention of experienced, qualified nursing staff a priority for health care organizations. The purpose of this paper is to describe a theoretical model of job retention for home health care nurses. The theoretical model is an integration of the findings of empirical research related to intent to stay and retention, components of Neal's theory of home health care nursing practice and findings from earlier work to develop an instrument to measure home health care nurses' job satisfaction. The theoretical model identifies antecedents to job satisfaction of home health care nurses. The antecedents are intrinsic and extrinsic job characteristics. The model also proposes that job satisfaction is directly related to retention and indirectly related to retention though intent to stay. Individual nurse characteristics are indirectly related to retention through intent to stay. The individual characteristic of tenure is indirectly related to retention through autonomy, as an intrinsic characteristic of job satisfaction, and intent to stay. The proposed model can be used to guide research that explores gaps in knowledge about intent to stay and retention among home health care nurses.

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.

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.

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.

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 ...

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 �

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.

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…

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

Alcohol Consumption and Academic Retention in First-Year College Students

Science.gov (United States)

Liguori, Gary; Lonbaken, Barb

2015-01-01

Objectives: This study attempted to identify relationships between alcohol consumption and first-to-second-year student retention among college students. Methods: 820 students in general education courses completed an online wellness assessment at four separate time points, including questions related to alcohol consumption. Data were analyzed…

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.

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.

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.

Retention factors in relation to organisational commitment in medical and information technology services

Directory of Open Access Journals (Sweden)

Jeannette van Dyk

2012-02-01

Full Text Available Orientation: Retaining staff with scarce and critical skills in the medical and information technology (IT industry has become a top priority because of skills shortages.Research purpose: The objectives of the study were to investigate empirically: (1 the relationship between employees’ satisfaction with organisational retention factors (measured by the Retention Factors Scale and their organisational commitment (measured by the Organisational Commitment Questionnaire and (2 whether gender, age, race and tenure groups differ significantly in terms of these variables.Motivation for the study: Medical and information technology professionals have specialised and hard to replace skills. They also have strong tendencies to leave their organisations and countries. Understanding the retention factors that will increase their organisational commitment may benefit the organisations who want to retain their valuable talent.Research design, approach and method: The researchers used a cross-sectional survey design to collect data from a purposive sample of 206 staff members who had scarce skills in a South African medical and information technology services company. Correlational and inferential statistics were computed to achieve the objectives.Main findings: The results showed that the participants’ satisfaction with retention factors has a significant relationship with their organisational commitment and that the biographical groups differ significantly in terms of the variables.Practical/managerial implications: The measured retention factors were all associated with human resource management practices that influence employees’ intentions to leave.Contribution/value-add: The results are important to managers who are interested in retaining staff who have scarce skills and provide valuable pointers for designing effective retention strategies.

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.

77 FR 3745 - Establishment of a One-Year Retention Period for Patent-Related Papers That Have Been Scanned...

Science.gov (United States)

2012-01-25

... past practice of indefinitely retaining the papers, which has been rendered unnecessary and not cost...] Establishment of a One-Year Retention Period for Patent-Related Papers That Have Been Scanned Into the Image... period of one year for patent-related papers that have been scanned into the Image File Wrapper system...

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.

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.

Correlations between boiling points and relative retention data for hydrocarbons

NARCIS (Netherlands)

Sojak, L.; Krupcik, J.; Rijks, J.A.

1974-01-01

An equation correlating retention indices, boiling points and activity coefficients is proposed. The equation can be applied not only to homologous series, but also to different classes of hydrocarbons.

European Top Managers’ Age-Related Workplace Norms and Their Organizations’ Recruitment and Retention Practices Regarding Older Workers

NARCIS (Netherlands)

Oude Mulders, J.; Henkens, K.; Schippers, J.

2017-01-01

Purpose: Top managers guide organizational strategy and practices, but their role in the employment of older workers is understudied. We study the effects that age-related workplace norms of top managers have on organizations’ recruitment and retention practices regarding older workers. We

European Top Managers' Age-Related Workplace Norms and Their Organizations' Recruitment and Retention Practices Regarding Older Workers

NARCIS (Netherlands)

Mulders, Jaap Oude; Henkens, Kene; Schippers, Joop

2017-01-01

Purpose: Top managers guide organizational strategy and practices, but their role in the employment of older workers is understudied. We study the effects that age-related workplace norms of top managers have on organizations' recruitment and retention practices regarding older workers. We

Affairs of State and Student Retention: An Exploratory Study of the Factors that Impact Student Retention in a Politically Turbulent Region

Science.gov (United States)

Ben-Tsur, Dalia

2007-01-01

This study examines the impact of a country's security unrest on student retention. It draws on the key factors that influence retention worldwide, adopts Bourdieu's notion of cultural capital and also brings in concepts related to terrorism and security unrest traditionally absent from theories on student retention. Based on a case study carried…

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.

Retaining the mental health nursing workforce: early indicators of retention and attrition.

Science.gov (United States)

Robinson, Sarah; Murrells, Trevor; Smith, Elizabeth M

2005-12-01

In the UK, strategies to improve retention of the mental health workforce feature prominently in health policy. This paper reports on a longitudinal national study into the careers of mental health nurses in the UK. The findings reveal little attrition during the first 6 months after qualification. Investigation of career experiences showed that the main sources of job satisfaction were caregiving opportunities and supportive working relationships. The main sources of dissatisfaction were pay in relation to responsibility, paperwork, continuing education opportunities, and career guidance. Participants were asked whether they predicted being in nursing in the future. Gender and ethnicity were related to likelihood to remain in nursing in 5 years time. Age, having children, educational background, ethnic background, and time in first job were associated with likelihood of remaining in nursing at 10 years. Associations between elements of job satisfaction (quality of clinical supervision, ratio of qualified to unqualified staff, support from immediate line manager, and paperwork) and anticipated retention are complex and there are likely to be interaction effects because of the complexity of the issues. Sustaining positive experiences, remedying sources of dissatisfaction, and supporting diplomats from all backgrounds should be central to the development of retention strategies.

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.

Adherence of pregnant women to Nordic dietary guidelines in relation to postpartum weight retention: results from the Norwegian Mother and Child Cohort Study.

Science.gov (United States)

von Ruesten, Anne; Brantsæter, Anne Lise; Haugen, Margaretha; Meltzer, Helle Margrete; Mehlig, Kirsten; Winkvist, Anna; Lissner, Lauren

2014-01-24

Pregnancy is a major life event for women and often connected with changes in diet and lifestyle and natural gestational weight gain. However, excessive weight gain during pregnancy may lead to postpartum weight retention and add to the burden of increasing obesity prevalence. Therefore, it is of interest to examine whether adherence to nutrient recommendations or food-based guidelines is associated with postpartum weight retention 6 months after birth. This analysis is based on data from the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. Diet during the first 4-5 months of pregnancy was assessed by a food-frequency questionnaire and maternal weight before pregnancy as well as in the postpartum period was assessed by questionnaires. Two Healthy Eating Index (HEI) scores were applied to measure compliance with either the official Norwegian food-based guidelines (HEI-NFG) or the Nordic Nutrition Recommendations (HEI-NNR) during pregnancy. The considered outcome, i.e. weight retention 6 months after birth, was modelled in two ways: continuously (in kg) and categorically (risk of substantial postpartum weight retention, i.e. ≥ 5% gain to pre-pregnancy weight). Associations between the HEI-NFG and HEI-NNR score with postpartum weight retention on the continuous scale were estimated by linear regression models. Relationships of both HEI scores with the categorical outcome variable were evaluated using logistic regression. In the continuous model without adjustment for gestational weight gain (GWG), the HEI-NFG score but not the HEI-NNR score was inversely related to postpartum weight retention. However, after additional adjustment for GWG as potential intermediate the HEI-NFG score was marginally inversely and the HEI-NNR score was inversely associated with postpartum weight retention. In the categorical model, both HEI scores were inversely related with risk of substantial postpartum weight retention

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 ...

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.

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

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

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

Multivariate analysis of chromatographic retention data as a supplementary means for grouping structurally related compounds.

Science.gov (United States)

Fasoula, S; Zisi, Ch; Sampsonidis, I; Virgiliou, Ch; Theodoridis, G; Gika, H; Nikitas, P; Pappa-Louisi, A

2015-03-27

In the present study a series of 45 metabolite standards belonging to four chemically similar metabolite classes (sugars, amino acids, nucleosides and nucleobases, and amines) was subjected to LC analysis on three HILIC columns under 21 different gradient conditions with the aim to explore whether the retention properties of these analytes are determined from the chemical group they belong. Two multivariate techniques, principal component analysis (PCA) and discriminant analysis (DA), were used for statistical evaluation of the chromatographic data and extraction similarities between chemically related compounds. The total variance explained by the first two principal components of PCA was found to be about 98%, whereas both statistical analyses indicated that all analytes are successfully grouped in four clusters of chemical structure based on the retention obtained in four or at least three chromatographic runs, which, however should be performed on two different HILIC columns. Moreover, leave-one-out cross-validation of the above retention data set showed that the chemical group in which an analyte belongs can be 95.6% correctly predicted when the analyte is subjected to LC analysis under the same four or three experimental conditions as the all set of analytes was run beforehand. That, in turn, may assist with disambiguation of analyte identification in complex biological extracts. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Linking local retention, self-recruitment, and persistence in marine metapopulations

KAUST Repository

Lett, Christophe; Nguyen-Huu, Tri; Cuif, Marion; Saenz Agudelo, Pablo; Kaplan, David M.

2015-01-01

Three indices of larval retention have been used in the literature to assess the tendency for self-maintenance of local marine populations: local retention (LR), self-recruitment (SR), and relative local retention (RLR). Only one of these, LR

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.

International perspectives on retention and persistence

Directory of Open Access Journals (Sweden)

Gary Burkholder

2014-06-01

Full Text Available Access to higher education globally is increasing dramatically; attainment of tertiary degrees is a high priority, as educational attainment is associated with increased personal incomes as well as growth of the middle class in developing countries. The purpose of this essay is to briefly examine retention and persistence issues from a global perspective, review some retention strategies that have been employed at schools outside the United States, and to identify several key factors that related to retention and persistence globally, including access, infrastructure, financial consideration, and readiness for tertiary education.  There exists an opportunity to utilize knowledge gained in the evolution of the higher education system in the United States to help address the problems associated with retention and persistence.   DOI: 10.18870/hlrc.v4i2.208

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

Hydrophilic interaction liquid chromatography in analysis of granisetron HCl and its related substances. Retention mechanisms and method development.

Science.gov (United States)

Maksić, Jelena; Tumpa, Anja; Stajić, Ana; Jovanović, Marko; Rakić, Tijana; Jančić-Stojanović, Biljana

2016-05-10

In this paper separation of granisetron and its two related substances in HILIC mode is presented. Separation was done on silica column derivatized with sulfoalkylbetaine groups (ZIC-HILIC). Firstly, retention mechanisms were assessed whereby retention factors of substances were followed in wide range of acetonitrile content (80-97%), at constant concentration of aqueous buffer (10mM) as well as at constant pH value of 3.0. Further, in order to developed optimal HILIC method, Design of Experiments (DoE) methodology was applied. For optimization full factorial design 3(2) was employed. Influence of acetonitrile content and ammonium acetate concentration were investigated while pH of the water phase was kept at 3.3. Adequacy of obtained mathematical models was confirmed by ANOVA. Optimization goals (α>1.15 and minimal run time) were accomplished with 94.7% of acetonitrile in mobile phase and 70 mM of ammonium acetate in water phase. Optimal point was in the middle of defined Design Space. In the next phase, robustness was experimetally tested by Rechtschaffen design. The investigated factors and their levels were: acetonitrile content (±1%), ammonium acetate molarity in water phase (±2 mM), pH value of water phase (±0.2) and column temperature (±4 °C). The validation scope included selectivity, linearity, accuracy and precision as well as determination of limit of detection (LOD) and limit of quantification (LOQ) for the related substances. Additionally, the validation acceptance criteria were met in all cases. Finally, the proposed method could be successfully utilized for estimation of granisetron HCl and its related substances in tablets and parenteral dosage forms, as well as for monitoring degradation under various stress conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Validating Student Satisfaction Related to Persistence, Academic Performance, Retention and Career Advancement within ODL Perspectives

Directory of Open Access Journals (Sweden)

Maximus Gorky Sembiring

2015-11-01

Full Text Available Student satisfaction associated with persistence, academic performance, retention, and its relations to career advancement were examined. It was aimed at measuring service quality (Servqual dimensions as a foundation of satisfaction and how, in what comportments, they were interrelated. The study was conducted under explanatory-design. Data was collected proportionally and purposively followed by congregating them through unified interviews. Population was 1,814 Universitas Terbuka students domiciled overseas; 350 questionnaires were dispersed, 169 completed. Satisfaction was assessed by examining Servqual dimensions. Importance-performance analysis (IPA and customer-satisfaction index (CSI were applied to measure satisfaction and the level of its importance. Structural equation model (SEM was then employed to examine influencing variables. Nine hypotheses developed were all validated by the analysis. Responsiveness, assurance, tangible, reliability, and empathy were in harmony to satisfaction. Career advancement, retention, academic performance, and persistence were influenced by satisfaction. Qualitative inquiry implemented afterwards was basically coherent with the quantitative findings.

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.

Characterizing retention in HAART as a recurrent event process: insights into 'cascade churn'.

Science.gov (United States)

Nosyk, Bohdan; Lourenço, Lillian; Min, Jeong Eun; Shopin, Dimitry; Lima, Viviane D; Montaner, Julio S G

2015-08-24

The benefits of HAART rely on continuous lifelong treatment retention. We used linked population-level health administrative data to characterize durations of HAART retention and nonretention. This is a retrospective cohort study. We considered individuals initiating HAART in British Columbia (1996-2012). An HAART episode was considered discontinued if individuals had a gap of at least 30 days between days in which medication was prescribed. We considered durations of HAART retention and nonretention separately, and used Cox proportional hazards frailty models to identify demographic and treatment-related factors associated with durations of HAART retention and nonretention. Six thousand one hundred fifty-two individuals were included in the analysis; 81.2% were male, 40.6% were people who inject drugs, and 42.8% initiated treatment with CD4 cell count less than 200 cells/μl. Overall, 29% were continuously retained on HAART through the end of follow-up. HAART episodes were a median 6.8 months (25th, 75th percentile: 2.3, 19.5), whereas off-HAART episodes lasted a median 1.9 months (1.2, 4.5). In Cox proportional hazards frailty models, durations of HAART retention improved over time. Successive treatment episodes tended to decrease in duration among those with multiple attempts, whereas off-HAART episodes remained relatively stable. Younger age, earlier stages of disease progression, and injection drug use were all associated with shorter durations of HAART retention and longer off-HAART durations. Metrics to monitor HAART retention, dropout, and reentry should be prioritized for HIV surveillance. Clinical strategies and public health policies are urgently needed to improve HAART retention, particularly among those at earlier stages of disease progression, the young, and people who inject drugs.

The Impact of a Junior Faculty Fellowship Award on Academic Advancement and Retention.

Science.gov (United States)

Connelly, Maureen T; Sullivan, Amy M; Chinchilla, Manuel; Dale, Margaret L; Emans, S Jean; Nadelson, Carol Cooperman; Notman, Malkah Tolpin; Tarbell, Nancy J; Zigler, Corwin M; Shore, Eleanor G

2017-08-01

Academic faculty experience barriers to career development and promotion. In 1996, Harvard Medical School (HMS) initiated an intramural junior faculty fellowship to address these obstacles. The authors sought to understand whether receiving a fellowship was associated with more rapid academic promotion and retention. Junior faculty fellowship recipients and all other instructor and assistant professors at HMS between 1996 and 2011 were identified. Using propensity score modeling, the authors created a matched comparison group for the fellowship recipients based on educational background, training, academic rank, department, hospital affiliation, and demographics. Time to promotion and time to leaving were assessed by Kaplan-Meier curves. A total of 622 junior faculty received fellowships. Faculty who received fellowships while instructors (n = 480) had shorter times to promotion to assistant professor (P Women instructors advanced more quickly than matched controls, while male instructors' rates of promotions did not differ. Fellowships to support junior faculty were associated with shorter times to promotion for instructors and more sustained faculty retention for both instructors and assistant professors. This suggests that relatively small amounts of funding early in faculty careers can play a critical role in supporting academic advancement and retention.

Nitrogen Retention in Coastal Marine Sediments—a Field Study of the Relative Importance of Biological and Physical Removal in a Danish Estuary

DEFF Research Database (Denmark)

Laurentius Nielsen, Søren; Risgaard-Petersen, Nils; Banta, Gary

2017-01-01

The aim of this study was to elucidate the relative importance of physical versus biological loss processes for the removal of microphytobenthic (MPB) bound nitrogen in a coastal environment at different times of the year via a dual isotope labeling technique. We used 51Cr, binding to inorganic...... were able to discern the relative importance of physical and biological processes. The isotope marking was supplemented with measurements of sediment chlorophyll biomass and oxygen fluxes, allowing us to evaluate MPB biomass as well as primary production vs. respiration in the sediment. In spring...... was physically dominated due to low MPB biomasses and activity combined with a significant storm event. Our data support the hypothesis that the relative balance between physical and biological processes in determining retention and removal of MPB-bound nitrogen changes seasonally....

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.

RESEARCH ANALYSIS ON MOOC COURSE DROPOUT AND RETENTION RATES

Directory of Open Access Journals (Sweden)

Marcela Gerogina GOMEZ-ZERMENO

2016-04-01

Full Text Available This research’s objective was to identify the terminal efficiency of the Massive Online Open Course “Educational Innovation with Open Resources” offered by a Mexican private university. A quantitative methodology was used, combining descriptive statistics and probabilistic models to analyze the levels of retention, completion, and desertion, as well as the characteristics of the students who completed the course. The results show a 14% of student retention and an 11.7% of student completion, relative to the total number of participants, who had some common characteristics: having a graduate (master or doctorate, being experienced in online education, committed to the course and self-taught. The participants who abandoned the course expressed the following reasons: problems with the course’s structure, limitations in the use of information and communication technologies or limited English proficiency, family reasons or low time disposition. It is recommended to take actions that will increase the knowledge in order to explain the MOOCs’ desertion rates and to strengthen their structures to improve the retention and completion rates.

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.

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.

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.

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.

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.

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…

The development of adaptive memory: Young children show enhanced retention of animacy-related information.

Science.gov (United States)

Aslan, Alp; John, Thomas

2016-12-01

Previous developmental work has indicated that animacy is a foundational ontogenetic category that is given priority already early in life. Here, we investigated whether such priority is also present in children's episodic memory, examining whether young children show enhanced retention of animacy-related information. Kindergartners and younger and older elementary school children were presented with fictitious (non)words (e.g., BULA, LAFE) paired with properties characteristic of humans (e.g., "likes music"), (nonhuman) animals (e.g., "builds nests"), and inanimate things (e.g., "has four edges") and were asked to rate the animacy status of each nonword. After a retention interval, a surprise recognition test for the nonwords was administered. We found enhanced recognition of nonwords paired with human and animal properties compared with (the same) nonwords paired with inanimate properties. The size of this animacy advantage was comparable across age groups, suggesting developmental invariance of the advantage over the age range examined (i.e., 4-11years). The results support a functional-evolutionary view on memory, suggesting that already young children's memory is "tuned" to process and retain animacy. Copyright © 2016 Elsevier Inc. All rights reserved.

5 CFR 2411.14 - Record retention and preservation.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Record retention and preservation. 2411.14 Section 2411.14 Administrative Personnel FEDERAL LABOR RELATIONS AUTHORITY, GENERAL COUNSEL OF THE... OFFICIAL INFORMATION § 2411.14 Record retention and preservation. The Authority, the General Counsel, the...

HPLC retention thermodynamics of grape and wine tannins.

Science.gov (United States)

Barak, Jennifer A; Kennedy, James A

2013-05-08

The effect of grape and wine tannin structure on retention thermodynamics under reversed-phase high-performance liquid chromatography conditions on a polystyrene divinylbenzene column was investigated. On the basis of retention response to temperature, an alternative retention factor was developed to approximate the combined temperature response of the complex, unresolvable tannin mixture. This alternative retention factor was based upon relative tannin peak areas separated by an abrupt change in solvent gradient. Using this alternative retention factor, retention thermodynamics were calculated. Van't Hoff relationships of the natural log of the alternative retention factor against temperature followed Kirchoff's relationship. An inverse quadratic equation was fit to the data, and from this the thermodynamic parameters for tannin retention were calculated. All tannin fractions exhibited exothermic, spontaneous interaction, with enthalpy-entropy compensation observed. Normalizing for tannin size, distinct tannin compositional effects on thermodynamic parameters were observed. The results of this study indicate that HPLC can be valuable for measuring the thermodynamics of tannin interaction with a hydrophobic surface and provides a potentially valuable alternative to calorimetry. Furthermore, the information gathered may provide insight into understanding red wine astringency quality.

76 FR 53667 - Establishing a One-Year Retention Period for Patent-Related Papers That Have Been Scanned Into...

Science.gov (United States)

2011-08-29

... replace the USPTO's past practice of indefinitely retaining the papers, which has been rendered... costs. The USPTO's past practice of indefinitely retaining the boxes of papers that it scans into IFW or...-Year Retention Period for Patent-Related Papers That Have Been Scanned Into the Image File Wrapper...

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.

Characterizing retention in HAART as a recurrent event process: insights into ‘cascade churn’

Science.gov (United States)

Nosyk, Bohdan; Lourenço, Lillian; Min, Jeong Eun; Shopin, Dimitry; Lima, Viviane D.; Montaner, Julio S.G.

2015-01-01

Objective The benefits of HAART rely on continuous lifelong treatment retention. We used linked population-level health administrative data to characterize durations of HAART retention and nonretention. Design This is a retrospective cohort study. Methods We considered individuals initiating HAART in British Columbia (1996–2012). An HAART episode was considered discontinued if individuals had a gap of at least 30 days between days in which medication was prescribed. We considered durations of HAART retention and nonretention separately, and used Cox proportional hazards frailty models to identify demographic and treatment-related factors associated with durations of HAART retention and nonretention. Results Six thousand one hundred fifty-two individuals were included in the analysis; 81.2% were male, 40.6% were people who inject drugs, and 42.8% initiated treatment with CD4 cell count less than 200 cells/μl. Overall, 29% were continuously retained on HAART through the end of follow-up. HAART episodes were a median 6.8 months (25th, 75th percentile: 2.3, 19.5), whereas off-HAART episodes lasted a median 1.9 months (1.2, 4.5). In Cox proportional hazards frailty models, durations of HAART retention improved over time. Successive treatment episodes tended to decrease in duration among those with multiple attempts, whereas off-HAART episodes remained relatively stable. Younger age, earlier stages of disease progression, and injection drug use were all associated with shorter durations of HAART retention and longer off-HAART durations. Conclusion Metrics to monitor HAART retention, dropout, and reentry should be prioritized for HIV surveillance. Clinical strategies and public health policies are urgently needed to improve HAART retention, particularly among those at earlier stages of disease progression, the young, and people who inject drugs. PMID:26372279

Whole-body retention studies of /sup 167/Tm--citrate. Estimation of radiation dose to humans from /sup 167/Tm--citrate

Energy Technology Data Exchange (ETDEWEB)

Hiraki, T; Ando, A [Kanazawa Univ. (Japan). School of Paramedicine; Mori, H; Ando, I; Sakamoto, K

1978-02-01

For the purpose of calculating absorbed dose to humans from /sup 167/Tm-citrate, the whole-body retention studies using 5 rats were carried out. Up to 40 days following intravenous injection of /sup 167/Tm-citrate, the whole-body counts were monitored with an animal counter. The whole-body retention curve was obtained with three exponential components. Namely, the 26% of the injected /sup 167/Tm-citrate had a biological half-time of 3.4 hours, 12.5% had a biological half-time of 99 hours and 61.5% had a biological half-time of 106 days. These results indicate, that three components consist of the rapid clearance from the kidneys, the retention in the liver and other soft tissues with relatively long half-time and the retention in the bones with long half-time. Based on these biological data and the MIRD Committee method, the average dose estimates to the bone and whole-body from intravenous administration of 1 mCi /sup 167/Tm-citrate were 7.08 rads and 1.28 rads, respectively.

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

Relating shear strength of unsaturated soils with capillary water retention curve

Directory of Open Access Journals (Sweden)

Zhou Annan

2016-01-01

Full Text Available This paper proposes a new water retention model for unsaturated soils, which takes into account capillary condensation of adsorbed water. In the proposed water retention model, the degree of saturation of a soil is separated into that based on capillary water and that based on adsorbed water. Through the analysis of a partially saturated two-cylinder system, a new shear strength criterion for unsaturated soils is proposed, in which only the degree of saturation based on capillary water contributes to the variation of shear strength with suction. The proposed shear strength criterion is justified against thermodynamic principles. The proposed strength criterion is compared against existing criteria in the literature, which shows that it provides a much improved prediction of the experimental data, for a wide range of suction values.

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.

Factors influencing intentions to stay and retention of nurse managers: a systematic review.

Science.gov (United States)

Brown, Pamela; Fraser, Kimberly; Wong, Carol A; Muise, Melanie; Cummings, Greta

2013-04-01

This systematic review aimed to explore factors known to influence intentions to stay and retention of nurse managers in their current position. Retaining staff nurses and recruiting nurses to management positions are well documented; however, there is sparse research examining factors that influence retention of nurse managers. Thirteen studies were identified through a systematic search of the literature. Eligibility criteria included both qualitative and quantitative studies that examined factors related to nurse manager intentions to stay and retention. Quality assessments, data extraction and analysis were completed on all studies included. Twenty-one factors were categorized into three major categories: organizational, role and personal. Job satisfaction, organizational commitment, organizational culture and values, feelings of being valued and lack of time to complete tasks leading to work/life imbalance, were prominent across all categories. These findings suggest that intentions to stay and retention of nurse managers are multifactoral. However, lack of robust literature highlights the need for further research to develop strategies to retain nurse managers. ImplICATIONS FOR NURSE MANAGEMENT: Health-care organizations and senior decision-makers should feel a responsibility to support front-line managers in relation to workload and span of control, and in understanding work/life balance issues faced by managers. © 2012 Blackwell Publishing Ltd.

Influence of transportation cost on long-term retention in clinic for HIV patients in rural Haiti.

Science.gov (United States)

Sowah, Leonard A; Turenne, Franck V; Buchwald, Ulrike K; Delva, Guesly; Mesidor, Romaine N; Dessaigne, Camille G; Previl, Harold; Patel, Devang; Edozien, Anthony; Redfield, Robert R; Amoroso, Anthony

2014-12-01

With improved access to antiretroviral therapy in resource-constrained settings, long-term retention in HIV clinics has become an important means of reducing costs and improving outcomes. Published data on retention in HIV clinics beyond 24 months are, however, limited. In our clinic in rural Haiti, we hypothesized that individuals residing in locations with higher transportation costs to clinic would have poorer retention than those who had lower costs. We used a retrospective cohort design to evaluate potential predictors of HIV clinic retention. Patient information was abstracted from the electronic medical records. Cox proportional hazards regression was used to identify independent predictors of 4-year clinic retention. There were 410 patients in our cohort, 266 (64.9%) females and 144 (35.1%) males. Forty-five (11%) patients lived in locations with transportation costs >$2. Males were 1.5 times more likely to live in municipalities with transportation costs to clinic of >$2. Multivariate analysis suggested that age transportation cost were independent predictors of loss to follow-up (LTFU): risk ratio of 2.98, 95% confidence interval (CI): 1.73 to 4.96, P transportation costs greater than $2 were 1.9 times more likely to be lost to care compared with those who paid less for transportation. HIV treatment programs in resource-constrained settings may need to pay closer attention to issues related to transportation cost to improve patient retention.

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

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…

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...

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

Turnover in the health workforce is a concern as it is costly and detrimental to organizational performance and quality of care. Most studies have focused on the influence of individual and organizational factors on an employee's intention to quit. Inspired by the observation that providing care is based on the duration of practices, tasks and processes (issues of time) rather than exchange values (wages), this paper focuses on the influence of working-time characteristics and wages on an employee's intention to stay. Using data from the WageIndicator web survey (N = 5,323), three logistic regression models were used to estimate health care employee's intention to stay for Belgium, Germany and the Netherlands. The first model includes working-time characteristics controlling for a set of sociodemographic variables, job categories, promotion and organization-related characteristics. The second model tests the impact of wage-related characteristics. The third model includes both working-time- and wage-related aspects. Model 1 reveals that working-time-related factors significantly affect intention to stay across all countries. In particular, working part-time hours, overtime and a long commuting time decrease the intention to stay with the same employer. The analysis also shows that job dissatisfaction is a strong predictor for the intention to leave, next to being a woman, being moderately or well educated, and being promoted in the current organization. In Model 2, wage-related characteristics demonstrate that employees with a low wage or low wage satisfaction are less likely to express an intention to stay. The effect of wage satisfaction is not surprising; it confirms that besides a high wage, wage satisfaction is essential. When considering all factors in Model 3, all effects remain significant, indicating that attention to working and commuting times can complement attention to wages and wage satisfaction to increase employees' intention to stay. These

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…

"To be or not to be Retained … That's the Question!" Retention, Self-esteem, Self-concept, Achievement Goals, and Grades.

Science.gov (United States)

Peixoto, Francisco; Monteiro, Vera; Mata, Lourdes; Sanches, Cristina; Pipa, Joana; Almeida, Leandro S

2016-01-01

Keeping students back in the same grade - retention - has always been a controversial issue in Education, with some defending it as a beneficial remedial practice and others arguing against its detrimental effects. This paper undertakes an analysis of this issue, focusing on the differences in student motivation and self-related variables according to their retention related status, and the interrelationship between retention and these variables. The participants were 695 students selected from two cohorts (5th and 7th graders) of a larger group of students followed over a 3-year project. The students were assigned to four groups according to their retention-related status over time: (1) students with past and recent retention; (2) students with past but no recent retention; (3) students with no past but recent retention; (4) students with no past or recent retention. Measures of achievement goal orientations, self-concept, self-esteem, importance given to school subjects and Grade Point Average (GPA) were collected for all students. Repeated measures MANCOVA analyses were carried out showing group differences in self-esteem, academic self-concept, importance attributed to academic competencies, task and avoidance orientation and academic achievement. To attain a deeper understanding of these results and to identify profiles across variables, a cluster analysis based on achievement goals was conducted and four clusters were identified. Students who were retained at the end of the school year are mainly represented in clusters with less adaptive motivational profiles and almost absent from clusters exhibiting more adaptive ones. Findings highlight that retention leaves a significant mark that remains even when students recover academic achievement and retention is in the distant past. This is reflected in the low academic self-concept as well as in the devaluation of academic competencies and in the avoidance orientation which, taken together, can undermine students

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.

The grit effect: predicting retention in the military, the workplace, school and marriage.

Science.gov (United States)

Eskreis-Winkler, Lauren; Shulman, Elizabeth P; Beal, Scott A; Duckworth, Angela L

2014-01-01

Remaining committed to goals is necessary (albeit not sufficient) to attaining them, but very little is known about domain-general individual differences that contribute to sustained goal commitment. The current investigation examines the association between grit, defined as passion and perseverance for long-term goals, other individual difference variables, and retention in four different contexts: the military, workplace sales, high school, and marriage. Grit predicted retention over and beyond established context-specific predictors of retention (e.g., intelligence, physical aptitude, Big Five personality traits, job tenure) and demographic variables in each setting. Grittier soldiers were more likely to complete an Army Special Operations Forces (ARSOF) selection course, grittier sales employees were more likely to keep their jobs, grittier students were more likely to graduate from high school, and grittier men were more likely to stay married. The relative predictive validity of grit compared to other traditional predictors of retention is examined in each of the four studies. These findings suggest that in addition to domain-specific influences, there may be domain-general individual differences which influence commitment to diverse life goals over time.

Retention behaviour of some estradiol derivatives on alumina in normal phase chromatography

Directory of Open Access Journals (Sweden)

MARIJANA M. ACANSKI

2003-03-01

Full Text Available The retention constants of variously substituted estradiol derivatives were measured as a function of the composition of various binary mobile phases in order to study the relationship between chemical structure and retention behaviour in TLC on alumina. The slopes and intercepts of the linear relationships between the retention constant RM and the logarithm of the volume fraction of the polar mobile phase component were calculated and are discussed in relation to the characteristics of the solute and mobile phase. The RFvalues and relative retention DRM of the compounds depend largely on the retention behaviour of their substituents. The results obtained in this investigation are compared with the results of the same derivatives obtained in previous investigations on silica gel.

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...

Soil Water Retention and Relative Permeability for Full Range of Saturation

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z. F.

2010-09-28

Common conceptual models for unsaturated flow often rely on the oversimplified representation of medium pores as a bundle of cylindrical capillaries and assume that the matric potential is attributed to capillary forces only. The adsorptive surface forces are ignored. It is often assumed that aqueous flow is negligible when a soil is near or at the residual water content. These models are successful at high and medium water contents but often give poor results at low water contents. These models do not apply to conditions at which water content is less than the residual water content. We extend the lower bound of existing water-retention functions and conductivity models from residual water content to the oven-dry condition (i.e., zero water content) by defining a state-dependent, residual-water content for a soil drier than a critical value. Furthermore, a hydraulic conductivity model for smooth uniform spheres was modified by introducing a correction factor to describe the film flow-induced hydraulic conductivity for natural porous media. The total unsaturated hydraulic conductivity is the sum of those due to capillary and film flow. The extended retention and conductivity models were verified with six datasets from the literature. Results show that, when the soil is at high and intermediate water content, there is no difference between the un-extended and the extended models; when the soil is at low water content, the un-extended models overestimate the water content but under-estimate the conductivity while the extended models match the retention and conductivity measurements well.

[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.

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.

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.

Estimation of hydraulic conductivities of Yucca Mountain tuffs from sorptivity and water retention measurements

International Nuclear Information System (INIS)

Zimmerman, R.W.; Bodvarsson, G.S.

1995-06-01

The hydraulic conductivity functions of the matrix rocks at Yucca Mountain, Nevada, are among the most important data needed as input for the site-scale hydrological model of the unsaturated zone. The difficult and time-consuming nature of hydraulic conductivity measurements renders it infeasible to directly measure this property on large numbers of cores. Water retention and sorptivity measurements, however, can be made relatively rapidly. The sorptivity is, in principle, a unique functional of the conductivity and water retention functions. It therefore should be possible to invert sorptivity and water retention measurements in order to estimate the conductivity; the porosity is the only other parameter that is required for this inversion. In this report two methods of carrying out this inversion are presented, and are tested against a limited data set that has been collected by Flint et al. at the USGS on a set of Yucca Mountain tuffs. The absolute permeability is usually predicted by both methods to within an average error of about 0.5 - 1.0 orders of magnitude. The discrepancy appears to be due to the fact that the water retention curves have only been measured during drainage, whereas the imbibition water retention curve is the one that is relevant to sorptivity measurements. Although the inversion methods also yield predictions of the relative permeability function, there are yet no unsaturated hydraulic conductivity data against which to test these predictions

Online Mate-Retention Tactics on Facebook Are Associated With Relationship Aggression.

Science.gov (United States)

Brem, Meagan J; Spiller, Laura C; Vandehey, Michael A

2015-10-01

A measure of Facebook-related mate-retention tactics was developed to investigate the relationship between online behaviors and intimate partner aggression. One hundred and seventy-seven young adults (65 men, 112 women) completed questionnaires that included measures of online and offline mate-retention tactics, Facebook jealousy, Facebook surveillance, and intimate partner violence. A factor analysis yielded four subscales for the Facebook Mate-Retention Tactic Inventory (FMRTI): Care and Affection, Jealousy and Surveillance, Possession Signals, and Punishment of Infidelity Threat. The FMRTI total scores were positively correlated with Facebook jealousy, Facebook surveillance, and use of offline mate-retention tactics. The Jealousy and Surveillance subscale uniquely predicted intimate partner psychological and physical aggression over and above existing measures. Facebook mate-retention tactics fully mediated the relation between Facebook jealousy and both intimate partner psychological and physical aggression. The current study provides preliminary evidence for conceptualizing Facebook as an environment for the use of mate-retention tactics that have real-life implications for intimate partner violence. © The Author(s) 2014.

Climatic variability and its role in regulating C, N and P retention in the James River Estuary

Science.gov (United States)

Bukaveckas, Paul A.; Beck, Michael; Devore, Dana; Lee, William M.

2018-05-01

Transformations and retention of C, N and P inputs to estuaries are subject to external factors such as discharge-driven variation in loading rates, and internal processes regulating biogeochemical cycles. We used an 8-year time series of finely resolved (monthly) mass balances for the tidal freshwater segment of the James River Estuary to assess the influence of discharge and temperature on C, N and P retention. Peak export and retention of organic, likely particulate, fractions occurred in months of highest discharge. With increasing discharge we observed higher mass retention, greater proportional retention (in relation to inputs) and more selective retention (with P retained preferentially over N and C). DIN retention was strongly influenced by water temperature with 10-fold high retention occurring at high (>20 °C) vs. low (estuaries is in dissolved inorganic form, and therefore subject to temperature dependent rates of biological assimilation and denitrification. By contrast, the bulk of the P load was in particulate form, which is retained via sediment trapping, and not appreciably affected by water temperature. The tidal freshwater estuary was an important site for nutrient removal where the accumulation of N- and P- rich materials may delay recovery in response to nutrient load reductions.

Employee retention and integrated disability management practices as demand side factors.

Science.gov (United States)

Habeck, Rochelle; Hunt, Allan; Rachel, Colleen Head; Kregel, John; Chan, Fong

2010-12-01

Demand-side employment research on company policies and practices related to retention and absence and disability management (ADM) can contribute to our understanding of employment issues related to people with disabilities from the employers' perspective. To examine company ADM and retention practices and their effectiveness, as well as how these company policies and practices might influence hiring of people with disabilities. Disability Management Employer Coalition employer members (N = 650) were surveyed by internet and the survey data were analyzed using descriptive statistics, correlation, and multiple regression. Ninety-five participants responded to the survey resulting in a response rate of 14%. Retention practice was found to be associated with retention effectiveness (r = .39, P ideas and involvement of employees, and assuring they know how their work and performance support the mission. ADM practice was related to improving health and managing health conditions (r = .26, P companies.

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).

Interception and retention of simulated cooling tower drift by vegetation

International Nuclear Information System (INIS)

Taylor, F.G. Jr.; Parr, P.D.

1978-01-01

A key issue concerning environmental impacts from cooling tower operation is the interception of drift by vegetation and the efficiency of plants in retaining the residue scavenged from the atmosphere. Chromated drift water, typical of the cooling towers of the Department of Energy's uranium enrichment facilities at Oak Ridge, Tennessee, was prepared using radio-labelled chromium. A portable aerosol generator was used to produce a spectrum of droplets with diameters (100 to 1300 μ) characteristic of cooling towers using state-of-the-art drift eliminators. Efficiency of interception by foliage varied according to leaf morphology with yellow poplar seedlings intercepting 72% of the deposition mass in contrast to 45% by loblolly pine and 24% by fescue grass. Retention patterns of intercepted deposition consisted of a short-time component (0 to 3 days) and a long-time component (3 to 63 days). Retention times, estimated from the regression equation of the long component, indicated that drift contamination from any deposition event may persist from between 8 and 12 weeks. In field situations adjacent to cooling towers, the average annual concentration of drift on vegetation at any distance remains relatively constant, with losses from weathering being compensated by chronic deposition

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.

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.

Studies on nitrogen retention in growing pigs

DEFF Research Database (Denmark)

Thorbek, G; Henckel, S; Chwalibog, André

1987-01-01

Nitrogen retention (RN) was measured in 60 barrows of Danish Landrace and a total of 470 balance periods was carried out during the growth period from 20 to 85 kg live weight. In the first serie (Expt A) six different feed compounds of high biological value (HBV) were fed to 48 barrows, while...... in the second serie (Expt B) 12 barrows were measured on feed compounds of HBV or low biological value (LBV). Three different levels of gross energy were used in Expt B. Individual differences of 10-20% in the pigs capability for nitrogen retention were observed. Nitrogen retention increased from 12 to 21 g N....../d on the HBV-compounds and was not influenced by increasing nitrogen or energy intake. Nitrogen retention was curvilinear in relation to metabolic live weight (kg0.75) in both series. A parabolic function on kg0.75 gave the best fit to the data with the following regression equations: Expt A + B: RN, g/d = 1...

Mate Value Discrepancy and Mate Retention Behaviors of Self and Partner.

Science.gov (United States)

Sela, Yael; Mogilski, Justin K; Shackelford, Todd K; Zeigler-Hill, Virgil; Fink, Bernhard

2017-10-01

This study investigated the relationship between perceived mate value discrepancy (i.e., the difference between an individual's mate value and their partner's mate value) and perceived frequency of mate retention performed by an individual relative to his or her partner. In two studies, participants in long-term, exclusive, sexual, heterosexual relationships reported their own, and their partner's, mate value and mate retention. Samples included 899 community members (Study 1) and 941 students and community members (Study 2). In Study 1, we documented that individuals with higher self-perceived short-term mate value, and who perceive their partner to have lower (vs. higher) short-term mate value, perform less frequent Benefit-Provisioning mate retention, controlling for the partner's Benefit-Provisioning mate retention. In Study 2, we documented that individuals who perceive that they could less easily replace their partner, and who perceive their partner could more (vs. less) easily replace them, perform more frequent mate retention (Benefit-Provisioning and Cost-Inflicting), controlling for the partner's mate retention. These results highlight the importance of assessing perceived discrepancies in mate value (notably, regarding the replaceability of self and partner with another long-term mate) and perceived mate retention behaviors of self, relative to partner, between men and women in long-term relationships. © 2016 Wiley Periodicals, Inc.

Skill retention and control room operator competency

International Nuclear Information System (INIS)

Stammers, R.B.

1981-12-01

The problem of skill retention in relation to the competency of control room operators is addressed. Although there are a number of related reviews of the literature, this particular topic has not been examined in detail before. The findings of these reviews are summarised and their implications for the area discussed. The limited research on skill retention in connection with process control is also reviewed. Some topics from cognitive and instructional psychology are also raised. In particular overlearning is tackled and the potential value of learning strategies is assessed. In conclusion the important topic of measurement of performance is introduced and a number of potentially valuable training approaches are outlined. (author)

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...

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.

Age-related changes relevant to health in women: design, recruitment, and retention strategies for the Longitudinal Assessment of Women (LAW) study.

Science.gov (United States)

Khoo, Soo Keat; O'Neill, Sheila; Travers, Catherine; Oldenburg, Brian

2008-01-01

The primary aim was to assess the age-related changes that occur in older women. This paper describes the study rationale and methods, recruitment, and retention strategies. The Longitudinal Assessment of Women (LAW) Study was a longitudinal, observational, and multidisciplinary evaluation of a population-based cohort of urban-living women, aged between 40 and 80 years at recruitment and randomly invited from a district in Brisbane (a city in Australia) via the electoral roll. Five hundred eleven women were recruited and stratified into four age groups (40-49, 50-59, 60-69, 70-79 years) and were assessed on three or four occasions each year, using interviews and diagnostic instruments (echocardiography, applination tonometry, dual-energy x-ray absorptiometry [DEXA]) Retention strategies included flexibility, accessibility, personalized attention, and feedback. From a sample frame of 1598 names, there were 1082 respondents, of whom 511 (47%) were successfully recruited from those eligible to participate. Recruitment was quickest for the oldest age group, 70-79 years, and slowest for the age group 40-49 years; all age groups achieved their required quota. A scheduling program was developed to minimize the number of visits and maximize the use of allocated time. The largest dropout was seen in year 1 of the study, with very few thereafter. Of the 9 deaths, cancer was the cause in 7. The retention rate after 5 years was 95.5%. The design of the present study, with careful attention to coordination and a personal approach, facilitated the completion of a 5-year study, enabling a collection of a set of wide-ranging data from almost all the women recruited. The information thus collected will form the basis of cross-linking analysis of the risk factors associated with health problems in aging women.

Historical and Future Trends in Studying the Development of Long-Term Retention.

Science.gov (United States)

Howe, Mark L.

2000-01-01

Considers the relative lack of research attention to retention in developmental psychology and recent findings on age differences in retention. Highlights unresolved issues and how Bauer and colleagues' work may help set the research agenda and contribute to a shift in how early childhood retention is studied. Discusses memory strength,…

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.

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

Total plasma clearance versus urinary plasma clearance of (51)Cr-EDTA in patients with cirrhosis with and without fluid retention

DEFF Research Database (Denmark)

Henriksen, Ulrik Lütken; Hansen, Hanne B; Ring-Larsen, Helmer

2015-01-01

the injected dose relative to the plasma concentration-time area, extrapolated to infinity. ClU was determined as urinary excretion relative to the plasma concentration-time area up to voiding. Results. In patients without fluid retention, the difference between ClP and ClU (ClP - ClU = ClΔ) was mean 4.5 m...

Clinicopathologic correlation of submacular membranectomy with retention of good vision in a patient with age-related macular degeneration.

Science.gov (United States)

Rosa, R H; Thomas, M A; Green, W R

1996-04-01

We present the clinicopathologic features of the eye of a patient with age-related macular degeneration who underwent submacular membranectomy and had retention of good visual acuity for almost 4 years despite recurrent choroidal neovascularization treated with krypton laser photocoagulation and mild expansion of the laser lesion with time. Histopathologic study of the surgically removed membrane from the right eye disclosed a thin fibrovascular membrane lined by retinal pigment epithelium on one surface. Microscopic examination of the right eye obtained post mortem disclosed a 2.75-mm (horizontal) x 2.1-mm (vertical) retinal pigment epithelium defect with overlying photoreceptor cell atrophy centered on the temporal parafoveal area, and a 0.6 x 0.1-mm subretinal pigment epithelium fibrovascular membrane with an area of retinal pigment epithelial hyperplasia and vascularization from the retina 0.4 mm temporal to the fovea. Basal laminar deposit was present in the region of the fovea and nasal parafoveal area.

The grit effect: predicting retention in the military, the workplace, school and marriage

Directory of Open Access Journals (Sweden)

Lauren eEskreis-Winkler

2014-02-01

Full Text Available Remaining committed to goals is necessary (albeit not sufficient to attaining them, but very little is known about domain-general individual differences that contribute to sustained goal commitment. The current investigation examines the association between grit, defined as passion and perseverance for long-term goals, other individual difference variables, and retention in four different contexts: the military, workplace sales, high school, and marriage. Grit predicted retention over and beyond established context-specific predictors of retention (e.g. intelligence, physical aptitude, Big Five personality traits, job tenure and demographic variables in each setting. Grittier soldiers were more likely to complete an Army Special Operations Forces (ARSOF selection course, grittier sales employees were more likely to keep their jobs, grittier students were more likely to graduate from high school, and grittier men were more likely to stay married. The relative predictive validity of grit compared to other traditional predictors of retention is examined in each of the four studies. These findings suggest that in addition to domain-specific influences, there may be domain-general individual differences which influence commitment to diverse life goals over time.

The Effect of Sleep on Children’s Word Retention and Generalization

Directory of Open Access Journals (Sweden)

Emma L. Axelsson

2016-08-01

Full Text Available In the first few years of life children spend a good proportion of time sleeping as well as acquiring the meanings of hundreds of words and their related associations. There is now ample evidence of the effects of sleep on memory in adults and the number of studies demonstrating the effects of napping and nocturnal sleep in children is also mounting. In particular, sleep appears to benefit children’s memory for recently-encountered novel words. The effect of sleep on children’s generalization of novel words across multiple items, however, is less clear. Given that sleep is polyphasic in the early years, made up of multiple episodes, and children’s word learning is gradual and strengthened slowly over time, it is highly plausible that sleep is a strong candidate in supporting children’s memory for novel words. Importantly, it appears that when children sleep shortly after exposure to novel word-object pairs retention is better than if sleep is delayed, suggesting that napping plays a vital role in long-term word retention for young children. Word learning is a complex, challenging and important part of development, thus the role that sleep plays in children’s retention of novel words is worthy of attention. As such, ensuring children get sufficient good quality sleep and regular opportunities to nap may be critical for strong language acquisition.

Safeguards Workforce Repatriation, Retention and Utilization

Energy Technology Data Exchange (ETDEWEB)

Gallucci, Nicholas [Brookhaven National Lab. (BNL), Upton, NY (United States); Poe, Sarah [Brookhaven National Lab. (BNL), Upton, NY (United States)

2015-10-01

Brookhaven National Laboratory was tasked by NA-241 to assess the transition of former IAEA employees back to the United States, investigating the rate of retention and overall smoothness of the repatriation process among returning safeguards professionals. Upon conducting several phone interviews, study authors found that the repatriation process went smoothly for the vast majority and that workforce retention was high. However, several respondents expressed irritation over the minimal extent to which their safeguards expertise had been leveraged in their current positions. This sentiment was pervasive enough to prompt a follow-on study focusing on questions relating to the utilization rather than the retention of safeguards professionals. A second, web-based survey was conducted, soliciting responses from a larger sample pool. Results suggest that the safeguards workforce may be oversaturated, and that young professionals returning to the United States from Agency positions may soon encounter difficulties finding jobs in the field.

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

Three-Year Retention Rates of Levetiracetam, Topiramate, and Oxcarbazepine: A Retrospective Hospital-Based Study.

Science.gov (United States)

Sunwoo, Jun-Sang; Park, Byeong-Su; Ahn, Seon Jae; Hwang, Sungeun; Park, Chan-Young; Jun, Jin-Sun; Kim, Dong Wook; Lee, Soon-Tae; Jung, Keun-Hwa; Park, Kyung-Il; Chu, Kon; Jung, Ki-Young; Lee, Sang Kun

We evaluated and compared the 3-year retention rates of levetiracetam (LEV), topiramate (TPM), and oxcarbazepine (OXC) in patients with epilepsy in routine clinical practice. We retrospectively reviewed medical records of patients with epilepsy who were newly prescribed LEV, TPM, or OXC from 2006 to 2010. The retention rates were estimated by the Kaplan-Meier analysis, and independent risk factors for drug discontinuation were analyzed by the Cox regression method. A total of 588 patients were included: LEV (n = 345), TPM (n = 190), and OXC (n = 53). Among them, 82% had focal epilepsy, whereas 14.8% had generalized epilepsy. The 3-year retention rates for LEV, TPM, and OXC, were 81.2%, 78.3%, and 54.7%, respectively. Levetiracetam and TPM had equivalent retention rates, whereas patients remained on OXC for a significantly shorter amount of time (P effects leading to drug withdrawal of OXC (87.5%) was higher than that of LEV (34.4%, P < 0.001) and TPM (52.5%, P = 0.012). The current study suggested that LEV and TPM had comparable retention profiles in the long-term treatment for both focal and generalized epilepsy. Meanwhile, OXC therapy seemed to be relatively less useful because of its poor tolerability.

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

Survival Analysis of Faculty Retention and Promotion in the Social Sciences by Gender.

Directory of Open Access Journals (Sweden)

Janet M Box-Steffensmeier

Full Text Available Recruitment and retention of talent is central to the research performance of universities. Existing research shows that, while men are more likely than women to be promoted at the different stages of the academic career, no such difference is found when it comes to faculty retention rates. Current research on faculty retention, however, focuses on careers in science, technology, engineering, and mathematics (STEM. We extend this line of inquiry to the social sciences.We follow 2,218 tenure-track assistant professors hired since 1990 in seven social science disciplines at nineteen U.S. universities from time of hire to time of departure. We also track their time to promotion to associate and full professor. Using survival analysis, we examine gender differences in time to departure and time to promotion. Our methods account for censoring and unobserved heterogeneity, as well as effect heterogeneity across disciplines and cohorts.We find no statistically significant differences between genders in faculty retention. However, we do find that men are more likely to be granted tenure than women. When it comes to promotion to full professor, the results are less conclusive, as the effect of gender is sensitive to model specification.The results corroborate previous findings about gender patterns in faculty retention and promotion. They suggest that advances have been made when it comes to gender equality in retention and promotion, but important differences still persist.

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.

A Study of Retention Trends of International Students at a Southwestern Public University

Science.gov (United States)

Wong Davis, Kristina Marie

2012-01-01

Literature on factors contributing to the retention of international students remained limited. The purpose of this study was to examine the factors related to retention of international undergraduate degree seeking students through conducting pairwise correlational analysis to test the relationship between retention and age, gender, country of…

Employee Engagement as a Predictor of Seafarer Retention: A Study among Indian Officers

Directory of Open Access Journals (Sweden)

Yogendra Bhattacharya

2015-06-01

Full Text Available This paper is part of a study of employee engagement and its relationship with seafarer safety, performance and retention. This section focuses on the impact of seafarer turnover, identifies and understands drivers of retention and their relevance in shipping, and explores the relationship of engagement with retention. It determines the correlation between retention and engagement and analyses drivers of retention from the seafarer's perspective. It also identifies aspects of shipboard life that can contribute towards higher retention. The study confirms that engagement was significantly and positively related with retention levels, while factor analysis isolated six contributory factors. The study also reveals that retention levels of officers employed directly by ship owners and by managers did not differ significantly, nor did they significantly differ between senior and junior officers.

Retention of minority participants in clinical research studies.

Science.gov (United States)

Keller, Colleen S; Gonzales, Adelita; Fleuriet, K Jill

2005-04-01

Recruitment of minority participants for clinical research studies has been the topic of several analytical works. Yet retention of participants, most notably minority and underserved populations, is less reported and understood, even though these populations have elevated health risks. This article describes two related, intervention-based formative research projects in which researchers used treatment theory to address issues of recruitment and retention of minority women participants in an exercise program to reduce obesity. Treatment theory incorporates a model of health promotion that allows investigators to identify and control sources of extraneous variables. The authors' research demonstrates that treatment theory can improve retention of minority women participants by considering critical inputs, mediating processes, and substantive participant characteristics in intervention design.

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.

[Academic stress, desertion, and retention strategies for students in higher education].

Science.gov (United States)

Suárez-Montes, Nancy; Díaz-Subieta, Luz B

2015-04-01

A systematic review was performed to specify the characteristics of academic stress that affect the mental health of the university population. To do this, recent publications regarding academic stress, student desertion, and retention strategies were examined. Throughout this text, we present the results of the review in terms of the definitions of academic stress, student desertion, and retention strategies. In the same way, we examine the interpretative models with regard to student desertion and approach retention strategies in higher education. We also review retention experiences of several other countries. In terms of Colombia, we present aspects related to student desertion and retention programs from the point of view of the National Ministry of Education and from the experience of some universities with consolidated programs.

Factors Affecting Customer Retention in the Airline Industry

Directory of Open Access Journals (Sweden)

Raghda Climis

2017-01-01

Full Text Available Purpose: This study empirically investigated the factors that affect customer retention in the airline industry in North Cyprus. These factors were service quality attributes, perceived safety, customer satisfaction, loyalty reward program, relationship commitment and customer loyalty. The study also investigated four different groups for purposes of travel (business, education, vacation and family visit in the empirical model. Methodology: A descriptive approach was chosen to conduct this research. A quanhip between customer retention and the related study factors; however, not all of these relations are signifcant. The results also showed that the different purposes of travel had different influences on the variables regarding the positive and signifcant relations between them. Some independent variables had a negative effect on the dependent variables. Conclusions: This research was limited to one group and place: the students of Eastern Mediterranean University in North Cyprus. Originality: This study connected the retention, loyalty, satisfaction and service quality factors as attributes. In addition, this research was the frst to include other independent factors affecting satisfaction and loyalty in a comparison between four different groups regarding the purpose of travel in the airline industry.

Retention of movement technique : Implications for primary prevention of ACL injuries

NARCIS (Netherlands)

Welling, Wouter; Benjaminse, Anne; Gokeler, Alli; Otten, Bert

2017-01-01

Background: Retention of movement technique is crucial in anterior cruciate ligament (ACL) injury prevention programs. It is unknown if specific instructions or video instructions result in changes in kinematic and kinetic measures during a relatively short training session, and in a retention test

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.

Strategies to improve recruitment and retention of older stroke survivors to a randomized clinical exercise trial.

Science.gov (United States)

Taylor-Piliae, Ruth E; Boros, Daniella; Coull, Bruce M

2014-03-01

Relatively few exercise randomized clinical trials (RCTs) among stroke survivors have reported the effectiveness of recruitment and retention strategies, despite its central importance to study integrity. Our objective is to examine recruitment and retention strategies used among a group of older community-dwelling stroke survivors for an exercise RCT. Recruitment strategies were multidimensional using both paid (ie, newspaper, radio and, television) and unpaid advertisements (ie, staff visits, flyers, and brochures placed at outpatient rehabilitation centers, physician offices, and community facilities working with older adults; free media coverage of the study, presentations at stroke support groups, relatives/friends, and study Web site) to obtain referrals. Retention strategies centered on excellent communication, the study participants' needs, and having dedicated study staff. Attrition rates and adherence to the intervention were used to examine the effectiveness of these retention strategies. A total of 393 referrals were received, 233 persons were screened, and 145 stroke survivors enrolled in the study. During 3 years of study recruitment, we achieved 97% of our enrollment target. We enrolled 62% of those screened. Study enrollment from paid advertising was 21.4% (n = 31), whereas unpaid advertisements resulted in 78.6% (n = 114) of our participants. Attrition was 10% (n = 14 dropouts), and adherence to the intervention was 85%. Recruitment and retention of participants in an exercise RCT are time and labor intensive. Multiple recruitment and retention strategies are required to ensure an adequate sample of community-dwelling stroke survivors. Many of these strategies are also relevant for exercise RCTs among adults with other chronic illnesses. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

A Temperament for Teaching? Associations Between Personality Traits and Beginning Teacher Performance and Retention

Directory of Open Access Journals (Sweden)

Kevin C. Bastian

2017-01-01

Full Text Available The “greening” (i.e., inexperience of the U.S. teacher workforce puts a premium on districts and schools hiring effective and persistent beginning teachers. Given the limitations of characteristics currently available at the time of hiring (e.g., academic ability, preparation type, we built off previous research in economics and psychology to investigate associations between personality traits and first-year teachers’ performance and retention in North Carolina public schools. Using the 5-factor model of personality, we find that conscientiousness is significantly associated with higher value-added estimates, higher evaluation ratings, and higher retention rates. Additionally, general self-efficacy, a subdomain of conscientiousness, is significantly associated with teacher value added and evaluation ratings. These conscientiousness results are consistent with a rich body of evidence connecting conscientiousness-related measures to employee performance and retention across professions, and they suggest that districts and schools should consider using personality trait measures, along with other valid indicators, as a way to improve teacher hiring decisions.

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)

“To be or not to be retained … That’s the question!”Retention,self - esteem,self - concept,achievement goalsand grades

Directory of Open Access Journals (Sweden)

Francisco Peixoto

2016-10-01

Full Text Available Keeping students back in the same grade – retention – has always been a controversial issue in Education, with some defending it as a beneficial remedial practice and others arguing against its detrimental effects. This paper undertakes an analysis of this issue, focusing on the differences in student motivation and self-related variables according to their retention related status, and the interrelationship between retention and these variables. The participants were 695 students selected from two cohorts (5th and 7th graders of a larger group of students followed over a three-year project. The students were assigned to four groups according to their retention-related status over time: 1 students with past and recent retention; 2 students with past but no recent retention; 3 students with no past but recent retention; 4 students with no past or recent retention. Measures of achievement goal orientations, self-concept, self-esteem, importance given to school subjects and Grade Point Average (GPA were collected for all students.Repeated measures MANCOVA analyses were carried out showing group differences in self-esteem, academic self-concept, importance attributed to academic competencies, task and avoidance orientation and academic achievement. To attain a deeper understanding of these results and to identify profiles across variables, a cluster analysis based on achievement goals was conducted and four clusters were identified. Students who were retained at the end of the school year are mainly represented in clusters with less adaptive motivational profiles and almost absent from clusters exhibiting more adaptive ones.Findings highlight that retention leaves a significant mark that remains even when students recover academic achievement and retention is in the distant past. This is reflected in the low academic self-concept as well as in the devaluation of academic competencies and in the avoidance orientation which, taken together, can

Retention of zinc and calcium from the human colon

International Nuclear Information System (INIS)

Sandstroem, B.C.; Cederblad, A.; Kivistoe, B.S.; Stenquist, B.; Andersson, H.

1986-01-01

Colonic retention of zinc and calcium was studied after installation during colonoscopy of 30 mumol of zinc and 6.4 mmol of calcium labeled with 65 Zn and 47 Ca, and measurement of the whole-body retention of the radionuclides. After cecal installation in nine patients, retention (day 13) of zinc was 3.5 +/- 2.1% (mean +/- SD) and of calcium 3.5 +/- 2.7%. The calculated mean absorption was 4.1% for zinc and 14.1% for calcium. Application at the hepatic flexure in four patients resulted in a mean retention (day 13) of 1.2% for zinc and 0.6% for calcium. Under prevailing conditions, colonic absorption of zinc is relatively small, compared to the uptake after oral administration. Colonic absorption of calcium could, however, account for a substantial part of the total calcium uptake

Continuous Improvement: A Way of Integrating Student Enrollment, Advising, and Retention Systems in a Metropolitan University.

Science.gov (United States)

Beeler, Karl J.; Moehl, Pamela J.

1996-01-01

The University of Missouri-St. Louis has discovered the value of continuous quality improvement methods in upgrading its core student-related administrative processes. As a result, it is increasing efficiency and personalizing a traditionally bureaucratic system of student service. Concurrent goals are to increase retention and decrease time to…

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...

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.

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

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

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.

Influence of the structure and the texture of materials on the radionuclides retention

International Nuclear Information System (INIS)

Rancon, Daniel.

1980-12-01

The solid materials occur with various structures and textures: powdery rocks with micro-gains or micro-cristals, impermeable, permeable or very little permeable compact rocks, homogeneous or inhomogeneous rocks. The retention of the elements in solution for a given physico-chemical equilibrium must be characterized by different retention coefficients according to the type materials. The massic distribution coefficient, Kd, must be used when the whole mass participates to the interactions. With the impermeable rocks, a surfacic distribution coefficient, Ka must be used; with weakly permeable rocks where only a fraction of the mass is involved only can be used the K'd which is evolutive with the impregnation time. This theoretical study, verified by experiments, values the relations between these coefficients, it shows the preponderant influence of granulometry and matricial permeability, the influence of grinding of the rocks on the measurements validity. It shows at last the most suitable methods to establish retention coefficients representative of natural media which will be able to be introduced in a realistic transfert model [fr

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

Retention behavior of resorcinarene-based cavitands on C8 and C18 stationary phases.

Science.gov (United States)

Bartó, Endre; Prauda, Ibolya; Kilár, Ferenc; Kiss, Ibolya; Felinger, Attila

2015-09-01

The understanding of the retention behavior of large molecules is an area of interest in liquid chromatography. Resorcinarene-based cavitands are cavity-shaped cyclic oligomers that can create host-guest interactions. We have investigated the chromatographic behavior of two types of cyclic tetramers as analytes in high-performance liquid chromatography. The experiments were performed at four different temperatures (15, 25, 35, 45°C) on two types of reversed stationary phases (C8 and C18 ) from two different manufacturers. We have found a huge difference between the retention of resorcinarenes and cavitands. In some cases, the retention factor of cavitands was even a hundred times larger than the retention factor of resorcinarenes. The retention of methylated derivates was two to four times larger compared to that of demethylated compounds on every column. The opposite retention behavior of the resorcinarenes and cavitands on the two types of stationary phases showed well the difference of the selectivity of the XTerra and BDS Hypersil columns. The retention mechanism was studied by the thermodynamic parameters calculated from the van't Hoff equation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Retention of alkaline earth elements in man

International Nuclear Information System (INIS)

Newton, D.

1990-06-01

The data on human metabolism and long-term retention of alkaline earth elements ( 133 Ba injected into six healthy male volunteers at age 25-81 y and 45 Ca and 85 Sr received by one healthy male volunteer) are presented. Excreta were collected for 2-3 weeks after injection of the tracer into an antecubital vein. Activity in urine, ashed faeces and early samples of blood plasma was determined by gamma-ray scintillation spectrometry. Whole body retention has been assessed through serial measurements of body radioactivity. The injected 133 Ba apparently became mainly skeletal within several days, much earlier than predicted by the ICRP model. The whole-body retention at 32 d ranged from 5 to 14%, the rate of loss correlating with the excretory plasma clearance rate. No age-related trends were identified in the metabolism of Ca and Sr. 2 refs, 2 figs

Career satisfaction and retention risk among Wisconsin internists.

Science.gov (United States)

Giriyappa, Pradeep; Sullivan, Kandis K

2009-09-01

Physician career satisfaction has been studied extensively, but career satisfaction as it relates to retention is less well studied. The objective was to assess the relationship between career satisfaction and retention in primary care internal medicine physicians in Wisconsin. In this descriptive quantitative study, survey data was assessed for correlations between career satisfaction, risk to retention, and demographics. The survey included 1231 primary care internal medicine physicians in the Wisconsin Medical Directory (2007). Responses were measured by career satisfaction variables, and demographics and retention variables for the purpose of correlations and regression analysis. Survey responses included 573 physicians. An additional 85 physicians were disqualified. The final survey group included 1146 physicians for a response rate of 50%. A total of 116 physicians (20.2%) reported anticipating leaving their current position, 84 (14.7%) physicians reported anticipating leaving the career of medicine. Identified at risk for retention were 144 (25.1%) physicians. The lowest career satisfaction scores were reported in the areas of compensation (3.19) and practice (3.42) on a scale of 1 (very dissatisfied) to 5 (very satisfied). The highest correlations to retention were associated with practice, followed by compensation satisfaction. The level of significance for this study was identified as 0.05, and the P-value was 0.000. The study findings reveal a significant risk to the stability of continuity of care for patients, and may cost Wisconsin health care organizations more than $35 million in recruitment costs to replace departing physicians.

“To be or not to be Retained … That’s the Question!” Retention, Self-esteem, Self-concept, Achievement Goals, and Grades

Science.gov (United States)

Peixoto, Francisco; Monteiro, Vera; Mata, Lourdes; Sanches, Cristina; Pipa, Joana; Almeida, Leandro S.

2016-01-01

Keeping students back in the same grade – retention – has always been a controversial issue in Education, with some defending it as a beneficial remedial practice and others arguing against its detrimental effects. This paper undertakes an analysis of this issue, focusing on the differences in student motivation and self-related variables according to their retention related status, and the interrelationship between retention and these variables. The participants were 695 students selected from two cohorts (5th and 7th graders) of a larger group of students followed over a 3-year project. The students were assigned to four groups according to their retention-related status over time: (1) students with past and recent retention; (2) students with past but no recent retention; (3) students with no past but recent retention; (4) students with no past or recent retention. Measures of achievement goal orientations, self-concept, self-esteem, importance given to school subjects and Grade Point Average (GPA) were collected for all students. Repeated measures MANCOVA analyses were carried out showing group differences in self-esteem, academic self-concept, importance attributed to academic competencies, task and avoidance orientation and academic achievement. To attain a deeper understanding of these results and to identify profiles across variables, a cluster analysis based on achievement goals was conducted and four clusters were identified. Students who were retained at the end of the school year are mainly represented in clusters with less adaptive motivational profiles and almost absent from clusters exhibiting more adaptive ones. Findings highlight that retention leaves a significant mark that remains even when students recover academic achievement and retention is in the distant past. This is reflected in the low academic self-concept as well as in the devaluation of academic competencies and in the avoidance orientation which, taken together, can undermine

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. ...

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.

More data on mercury absorption in relation to dietary treatment in rats

International Nuclear Information System (INIS)

Kostial, K.; Blanusa, M.; Rabar, I.; Simonovic, I.

1981-01-01

The kinetics of mercury (Hg) absorption in relation to diet by determining whole body (WB), carcass (C) and gut (G) retention in control and milk-fed rats 6, 9, 12 and 15 days after oral administration of 203 Hg have been studied. All retention values were higher in the milk-fed than in control rats during the experimental period. The higher WB retention in the milk-fed animals was primarily due to increased G retention especially at shorter time intervals. Animals on the milk diet had in the C, higher retention values, and in the G, higher retention and longer residence time. There was no evidence that Hg from the gut compartment entered into other parts of the body within the observation period. More evidence is needed about the effect of other dietary treatments on Hg metabolism. (Auth.)

Seed Implant Retention Score Predicts the Risk of Prolonged Urinary Retention After Prostate Brachytherapy

International Nuclear Information System (INIS)

Lee, Hoon K.; Adams, Marc T.; Shi, Qiuhu; Basillote, Jay; LaMonica, Joanne; Miranda, Luis; Motta, Joseph

2010-01-01

Purpose: To risk-stratify patients for urinary retention after prostate brachytherapy according to a novel seed implant retention score (SIRS). Patients and Methods: A total of 835 patients underwent transperineal prostate seed implant from March 1993 to January 2007; 197 patients had 125 I and 638 patients had 103 Pd brachytherapy. Four hundred ninety-four patients had supplemental external-beam radiation. The final downsized prostate volume was used for the 424 patients who had neoadjuvant hormone therapy. Retention was defined as reinsertion of a Foley catheter after the implant. Results: Retention developed in 7.4% of patients, with an average duration of 6.7 weeks. On univariate analysis, implant without supplemental external-beam radiation (10% vs. 5.6%; p = 0.02), neoadjuvant hormone therapy (9.4% vs. 5.4%; p = 0.02), baseline α-blocker use (12.5% vs. 6.3%; p = 0.008), and increased prostate volume (13.4% vs. 6.9% vs. 2.9%, >45 cm 3 , 25-45 cm 3 , 3 ; p = 0.0008) were significantly correlated with increased rates of retention. On multivariate analysis, implant without supplemental external-beam radiation, neoadjuvant hormone therapy, baseline α-blocker use, and increased prostate volume were correlated with retention. A novel SIRS was modeled as the combined score of these factors, ranging from 0 to 5. There was a significant correlation between the SIRS and retention (p < 0.0001). The rates of retention were 0, 4%, 5.6%, 9%, 20.9%, and 36.4% for SIRS of 0 to 5, respectively. Conclusions: The SIRS may identify patients who are at high risk for prolonged retention after prostate brachytherapy. A prospective validation study of the SIRS is planned.

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.

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.

Healthcare Learning Community and Student Retention

Science.gov (United States)

Johnson, Sherryl W.

2014-01-01

Teaching, learning, and retention processes have evolved historically to include multifaceted techniques beyond the traditional lecture. This article presents related results of a study using a healthcare learning community in a southwest Georgia university. The value of novel techniques and tools in promoting student learning and retention…

Effects of temperature and surface contamination on D retention in ultrathin Li films on TZM

Energy Technology Data Exchange (ETDEWEB)

Capece, A.M., E-mail: acapece@pppl.gov [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Roszell, J.P. [Princeton University, Department of Chemical and Biological Engineering, Princeton, NJ (United States); Skinner, C.H. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Koel, B.E. [Princeton University, Department of Chemical and Biological Engineering, Princeton, NJ (United States)

2015-08-15

In this work, we investigate deuterium retention at the Mo–Li interface by studying thin Li films three monolayers thick on a TZM Mo alloy. Li films at temperatures between 315 and 460 K were exposed to a deuterium ion beam and D retention was measured using temperature programmed desorption. In the absence of oxygen, D is retained as LiD, and the relative amount of retained D decreases with increasing substrate temperature. In three-monolayer thick lithium oxide films, the amount of D retained was 2.5 times higher than the amount retained as LiD in the metallic Li film. However, oxygen reduces the thermal stability of D in the film, causing D{sub 2}O and D{sub 2} to be released from the surface at temperatures 150–200 K below the LiD decomposition temperature. These results highlight the importance of maintaining a metallic Li layer for high D retention in Li films on TZM at elevated temperatures.

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.

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

Psychometric Evaluation and Cultural Correlates of the Mate Retention Inventory–Short Form (MRI-SF in Iran

Directory of Open Access Journals (Sweden)

Mohammad Atari

2017-02-01

Full Text Available The current study investigated the psychometric properties of the Persian translation of the Mate Retention Inventory–Short Form (MRI-SF in Iran. We also investigated sex differences in the use of mate retention tactics and investigated the relationships between mate retention behaviors and a number of related cultural constructs. Participants (N = 308 ranged in age from 18 to 57 years. All participants were in a committed romantic relationship, with mean relationship length of 63.5 months (SD = 73.8. Participants completed the Persian translation of the MRI-SF and measures of religiosity, relationship satisfaction, self-esteem, and socioeconomic status. Cultural measures specific to Iran were also included, such as Mahr (for married individuals, self-perceived Qeiratiness (for men, and self-perceived jealousy (for women. Mahr is a mandatory amount of money or possessions paid or promised to be paid by the groom to the bride at the time of the marriage contract. Qeirati is a male-specific adjective in Persian meaning protective against unwanted attention toward a man’s romantic partner. Female jealousy is usually regarded the counterpart of male Qeiratiness in Iranian culture. The 19 mate retention tactics formed a two-component structure, consistent with previous research. Results demonstrate adequate internal consistency of 2-item assessments of mate retention tactics. Observed sex differences accorded with previous mate retention research and are discussed in reference to evolutionary perspectives on human mating. Several significant associations emerged between mate retention tactics and Iranian culture-specific variables and are discussed from a cross-cultural perspective.

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.

Emotional intelligence in nurse management and nurse job satisfaction and retention: a scoping review protocol.

Science.gov (United States)

Phillips, Jacqueline; Harris, Janet

2017-11-01

The objective of this review is to map what is known about emotional intelligence (EI) in relation to staff job satisfaction and retention in nursing, and the tools that are used to measure EI in this context. The primary question of this review is: What is known about nurse managers' EI as it relates to staff job satisfaction and retention in nursing?Sub-question 1: What tools are being used to measure nurse managers' EI and what theoretical frameworks are they based on?Sub-question 2: What gaps exist in the research related to nurse managers' EI as it relates to staff job satisfaction and retention in nursing?

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...

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.

Causes and Recommendations for Unanticipated Ink Retention Following Tattoo Removal Treatment

Science.gov (United States)

Chen, Cynthia L.; Desai, Alpesh; Desai, Tejas

2013-01-01

While placement of ink into the skin is a long-standing tradition, patients are now seeking tattoo removal on a more frequent basis. Once considered acceptable removal options, tattoo ink removal via physical destruction included dermabrasion, chemical destruction, salabrasion, thermal destruction, and cryotherapy. Now these options are used extremely infrequently. These modalities provided unpredictable results and often required prolonged healing times and left patients with skin discoloration, pain, scarring, and ink retention. Even the widely adopted use of lasers, now considered the gold standard method, offers some level of unpredictability surrounding the natural progression of ink resolution. Multiple factors need to be taken into consideration when successfully removing tattoo pigment including the modalities used, number and frequency of treatments, proper device technique, and physiological barriers to tattoo removal. This paper serves to elucidate the common causes of ink retention following tattoo removal treatment with recommendations on how best to address this relatively common occurrence. PMID:23882312

Essential Elements for Recruitment and Retention: Generation Y

Science.gov (United States)

Luscombe, Jenna; Lewis, Ioni; Biggs, Herbert C.

2013-01-01

Purpose: Generation Y (Gen Y) is the newest and largest generation entering the workforce. Gen Y may differ from previous generations in work-related characteristics which may have recruitment and retention repercussions. Currently, limited theoretically-based research exists regarding Gen Y's work expectations and goals in relation to…

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.

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

were incentives, communication strategies, new questionnaire format, participant case management, behavioural and methodological interventions. For 34 of the included trials, retention was response to postal and electronic questionnaires with or without medical test kits. For four trials, retention was the number of participants remaining in the trial. Included trials were conducted across a spectrum of disease areas, countries, healthcare and community settings. Strategies that improved trial retention were addition of monetary incentives compared with no incentive for return of trial-related postal questionnaires (RR 1.18; 95% CI 1.09 to 1.28, P value reminders (RR 2.08; 95% CI 1.11 to 3.87, P value = 0.02) and a 'package' of postal communication strategies with reminder letters appeared to be better than standard procedures (RR 1.43; 95% CI 1.22 to 1.67, P value reminders, or questionnaire question order either increased or decreased trial questionnaire response/retention. There was also no evidence that a telephone survey was either more or less effective than a monetary incentive and a questionnaire. As our analyses are based on single trials, the effect on questionnaire response of using offers of charity donations, sending reminders to trial sites and when a questionnaire is sent, may need further evaluation. Case management and behavioural strategies used for trial retention may also warrant further evaluation. Authors' conclusions Most of the retention trials that we identified evaluated questionnaire response. There were few evaluations of ways to improve participants returning to trial sites for trial follow-up. Monetary incentives and offers of monetary incentives increased postal and electronic questionnaire response. Some other strategies evaluated in single trials looked promising but need further evaluation. Application of the findings of this review would depend on trial setting, population, disease area, data collection and follow-up procedures. PLAIN

Retention of community college students in online courses

Science.gov (United States)

Krajewski, Sarah

The issue of attrition in online courses at higher learning institutions remains a high priority in the United States. A recent rapid growth of online courses at community colleges has been instigated by student demand, as they meet the time constraints many nontraditional community college students have as a result of the need to work and care for dependents. Failure in an online course can cause students to become frustrated with the college experience, financially burdened, or to even give up and leave college. Attrition could be avoided by proper guidance of who is best suited for online courses. This study examined factors related to retention (i.e., course completion) and success (i.e., receiving a C or better) in an online biology course at a community college in the Midwest by operationalizing student characteristics (age, race, gender), student skills (whether or not the student met the criteria to be placed in an AFP course), and external factors (Pell recipient, full/part time status, first term) from the persistence model developed by Rovai. Internal factors from this model were not included in this study. Both univariate analyses and multivariate logistic regression were used to analyze the variables. Results suggest that race and Pell recipient were both predictive of course completion on univariate analyses. However, multivariate analyses showed that age, race, academic load and first term were predictive of completion and Pell recipient was no longer predictive. The univariate results for the C or better showed that age, race, Pell recipient, academic load, and meeting AFP criteria were predictive of success. Multivariate analyses showed that only age, race, and Pell recipient were significant predictors of success. Both regression models explained very little (<15%) of the variability within the outcome variables of retention and success. Therefore, although significant predictors were identified for course completion and retention, there are still

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.…

Assessing knowledge retention in construction organisations: Cases from the UAE

Directory of Open Access Journals (Sweden)

Mohammed Arif

2012-05-01

Full Text Available Purpose: The purpose of this paper is to present different issues facing the problem of knowledge retention by construction sector companies in the UAE. Methodology: Existing framework in the area of knowledge retention has been used to assess three large construction consultancies in the UAE. The case study methodology used in this paper highlights some key issues in the area of knowledge retention in the UAE. Findings: Based on the analysis of the knowledge retention system the major drivers for its successful implementation are prevalence of a culture of sharing knowledge, reward and recognition for sharing knowledge, a technology platform that can accommodate multi formats of files, awareness of knowledge retention system and its benefits among its employees, and top management support. Research Limitations: The paper presents three case studies and draws conclusions about the UAE construction sector. Although the three companies are large companies, there are several Small and Medium sized Enterprise (SME operating in the construction sector in the UAE. Future researchers need to look at these SMEs. Originality / Value: Through the three case studies, several issues related to the implementation of robust knowledge retention practices have been identified and highlighted for the UAE construction sector.

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.

Assessing Potential Additional PFAS Retention Processes in the Subsurface

Science.gov (United States)

Brusseau, M. L.

2017-12-01

Understanding the transport and fate of per- and poly-fluorinated alkyl substances (PFASs) in the subsurface is critical for accurate risk assessments and design of effective remedial actions. Current conceptual and mathematical models are based on an assumption that solid-phase adsorption is the sole source of retention for PFASs. However, additional retention processes may be relevant for PFAS compounds in vadose-zone systems and in source zones that contain trapped immiscible organic liquids. These include adsorption at the air-water interface, partitioning to the soil atmosphere, adsorption at the NAPL-water interface, and absorption by NAPL. A multi-process retention model is proposed to account for these potential additional sources of PFAS retardation. An initial assessment of the relative magnitudes and significance of these retention processes was conducted for three representative PFASs, perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and 8:2 fluorotelomer alcohol (FTOH). Data collected from the literature were used to determine measured or estimated values for the relevant distribution coefficients, which were in turn used to calculate retardation factors for a representative porous medium. Adsorption at the air-water interface was shown to be a primary source of retention for PFOA and PFOS, contributing approximately 80% of total retardation. Adsorption to NAPL-water interfaces and absorption by bulk NAPL were also shown to be significant sources of retention for PFOS and PFOA. The latter process was the predominant source of retention for 8:2 FTOH, contributing 98% of total retardation. These results indicate that we may anticipate significant retention of PFASs by these additional processes. In such cases, retardation of PFASs in source areas may be significantly greater than what is typically estimated based on the standard assumption of solid-phase adsorption as the sole retention mechanism. This has significant ramifications for

Chromatographic determination of the relative retention of isotopic species of oxygen in methanol and methan-d3-ol

International Nuclear Information System (INIS)

Pauls, R.E.; Mahle, N.H.; Shepard, A.T.; Gaw, J.C.; Rogers, L.B.

1976-08-01

A high-precision gas chromatograph was used in conjunction with a quadrupole mass filter and an on-line computer to study the fractionation of oxygen isotopes by Porapak T and glycerol in CH 3 OH and CD 3 OH as a function of temperature. Values of relative retention on the order of 1.002 compared favorably with results for the vapor pressure ratio obtained by classical means. Differences from unity were much smaller for the activity-coefficient ratio than for the vapor-pressure ratio. Differential thermodynamic data were also reported

The Effect of Instant Messaging on Lecture Retention

Science.gov (United States)

McVaugh, Nathan Kant

2012-01-01

The impact of instant message interruptions via computer on immediate lecture retention for college students was examined. While watching a 24-minute video of a classroom lecture, students received various numbers of related-to-lecture ("Is consistent use of the eye contact method necessary for success?") versus not-related-to lecture…

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.

University First Year Advisors: A network approach for first year student transition and retention. A Practice Report.

Directory of Open Access Journals (Sweden)

Geraldine Box

2012-03-01

Full Text Available Focussing expressly on student support and retention, improving the first year experience has been addressed by Murdoch University through the implementation of a School discipline-specific network of professional First Year Advisors (FYAs. FYA initiatives, both broad-based and varied, have been developed in alignment with the changing needs of students as identified throughout the semesters. A combination of outreach telephone campaigns and face-to-face student support enables FYAs to conduct a "just in time" approach to positively increase student engagement, and ultimately, retention. With a bespoke database, FYAs and academic staff have been able to streamline the process of reporting students in need of support, and gather data relating to student retention. The FYA program is yet to be formally evaluated although initial feedback and student consultation is promising. This paper outlines the program's development, current initiatives and expected outcomes.  

Retention of Knowledge following training of students in Basic Trauma Life Support.

Science.gov (United States)

Lim, K G; Lum, S K; Burud, I A S

2016-12-01

In the course of their undergraduate training at the International Medical University, students receive a Basic Trauma Life Support course. We wanted to test the long-term retention of knowledge (after 16 months) of third year medical students who had received training in Basic Trauma Life Support Method: To assess the retention of knowledge one cohort of students who received the training course were tested again 16 months later using the same 30 question One Best Answer quiz. Seventy-three students who underwent the course sat for the Retention test. The number of students who passed the Retention test was not significantly different from the test taken immediately after the course. The mean scores, 62.5% and 59.5% respectively, were however significantly different. Our study involves a relatively long interval between the course and retention of knowledge test shows encouraging results.

Recruitment and Retention Problems in Paradise? Lessons from the Northern Mariana Islands.

Science.gov (United States)

Rude, Harvey; And Others

This paper reports on a study that examined teacher recruitment and retention practices in the Northern Mariana Islands public school system. The study was conducted due to shortages of special education teachers and related services personnel. Based on a review of school district documents on recruitment and retention practices and interviews…

Nutrient Cycling and Retention Along a Littoral Gradient in a Dutch Shallow Lake in Relation to Water Level Regime

NARCIS (Netherlands)

Sollie, S.; Verhoeven, J.T.A.

Littoral zones are characterized by gradients in depth and vegetation biomass, influencing nutrient retention capacity. A field experiment was conducted in a Phragmites australis dominated littoral zone to investigate nutrient retention and its effect on surface water quality. Measurements were done

Strategy for reduced calibration sets to develop quantitative structure-retention relationships in high-performance liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Andries, Jan P.M. [University of Professional Education, Department of Life Sciences, P.O. Box 90116, 4800 RA Breda (Netherlands); Claessens, Henk A. [University of Professional Education, Department of Life Sciences, P.O. Box 90116, 4800 RA Breda (Netherlands); Eindhoven University of Technology, Department of Chemical Engineering and Chemistry, Laboratory of Polymer Chemistry, P.O. Box 513 (Helix, STW 1.35), 5600 MB Eindhoven (Netherlands); Heyden, Yvan Vander [Department of Analytical Chemistry and Pharmaceutical Technology, Vrije Universiteit Brussel-VUB, Laarbeeklaan 103, B-1090 Brussels (Belgium); Buydens, Lutgarde M.C., E-mail: L.Buydens@science.ru.nl [Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands)

2009-10-12

In high-performance liquid chromatography, quantitative structure-retention relationships (QSRRs) are applied to model the relation between chromatographic retention and quantities derived from molecular structure of analytes. Classically a substantial number of test analytes is used to build QSRR models. This makes their application laborious and time consuming. In this work a strategy is presented to build QSRR models based on selected reduced calibration sets. The analytes in the reduced calibration sets are selected from larger sets of analytes by applying the algorithm of Kennard and Stone on the molecular descriptors used in the QSRR concerned. The strategy was applied on three QSRR models of different complexity, relating logk{sub w} or log k with either: (i) log P, the n-octanol-water partition coefficient, (ii) calculated quantum chemical indices (QCI), or (iii) descriptors from the linear solvation energy relationship (LSER). Models were developed and validated for 76 reversed-phase high-performance liquid chromatography systems. From the results we can conclude that it is possible to develop log P models suitable for the future prediction of retentions with as few as seven analytes. For the QCI and LSER models we derived the rule that three selected analytes per descriptor are sufficient. Both the dependent variable space, formed by the retention values, and the independent variable space, formed by the descriptors, are covered well by the reduced calibration sets. Finally guidelines to construct small calibration sets are formulated.

Crust growth and gas retention in synthetic Hanford waste

International Nuclear Information System (INIS)

Bryan, S.A.; Pederson, L.R.; Scheele, R.D.

1992-03-01

The focus of the work described here is to examine the principal contributing factors leading to slurry growth and gas retention within waste from a particular high-level waste tanks on the Hanford Site. Laboratory studies of aged synthetic waste have shown that the waste retains gases in the form of bubble attachment to solid particles. This attachment phenomenon is related to the presence of organic constituents (HEDTA, EDTA, and citrate) added to the waste matrix. The mechanism for bubble attachment is related to the hydrophobic surface produced by the organic complexant. The formation of a stable gas bubble/solid interaction is believed to be responsible for crust flotation and gas retention in the synthetic waste used here

Effects of glibenclamide on memory retention of passive avoidance learning in rats

Directory of Open Access Journals (Sweden)

MH. Esmaeili

2017-08-01

Full Text Available Background: Glucose increases memory in rats, and inhibit memory impairments produced by morphine. One mechanism by which glucose might act on memory via regulating the ATP-sensitive potassium channel. Objective: The aim of present study was to investigate the effects of glibenclamide on memory retention of passive avoidance learning in rats. Methods: This experimental study has been conducted in Qazvin University of Medical Sciences (2016. Forty male Wistar rats were divided into: Control, DMSO and glibenclamide groups (n=8. All rats were trained in a passive avoidance task (50 Hz, 1 mA, 3 s. DMSO (0.2 ml or glibenclamide (1, 2, 5 mg/kg, i.p. were injected for 10 days before training. Retention test was done 48 h later. Memory retention of each animal was measured as latency takes to enter the dark chamber. Findings: The time spent in the light chamber area before entering to the dark area and total time spent in the light chamber in the glibenclamide groups were less than control group. These times in the glibenclamide (5 mg/kg group was significantly lower than control group (P<0.05, conversely total time spent in the dark chamber in the glibenclamide groups were higher than control group. Conclusion: Glibenclamide, as an ATP-sensitive potassium channel blocker, may reduce memory retention by increasing insulin levels and, consequently, reducing blood glucose levels.

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.

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...

Evaluation of a Community College's Nursing Faculty Advising Program Relative to Students' Satisfaction and Retention

Science.gov (United States)

Harrell, Johnna C.; Reglin, Gary

2018-01-01

Problem was the community college recognized a decline in student retention rates from 2009 to 2012 in the School of Nursing. Purpose of this program evaluation was to evaluate a faculty advising program (FAP) in the School of Nursing at a community college in regard to students' satisfaction and retention. Evaluation period was from Fall 2012 to…

Evaluation for In-Vessel Retention Capabilities with In-Vessel Injection and External Reactor Vessel Cooling

International Nuclear Information System (INIS)

Lee, Jeong Seong; Ryu, In Chul; Moon, Young Tae

2016-01-01

If the accident has not progressed to the point of substantial changes in the core geometry, establishing adequate cooling is as straightforward as re-establishing flow through the reactor core. However, if the accident has progressed to the point where the core geometry is substantially altered as a result of material melting and relocation, as was the case in the TMI-2 accident, the means of cooling the debris are not as straightforward. From this time on, the reactor core was either completely or nearly covered by water, with high pressure injection flow initiated shortly after three hours into the accident. However, the core debris was not coolable in this configuration and a substantial quantity of molten core material drained into the bypass region, with approximately twenty metric tons of molten debris draining into the reactor pressure vessel (RPV) lower head. Hence, the core configuration developed at approximately three hours into the accident was not coolable, even submerged in water. The purpose of this paper is to evaluate in-vessel retention capabilities with in-vessel injection (IVI) and external reactor vessel cooling (ERVC) available in a reactor application by using the integrated severe accident analysis code. The MAAP5 models were improved to facilitate evaluation of the in-vessel retention capability of APR1400. In-vessel retention capabilities have been analyzed for the APR1400 using the MAAP5.03 code. The results show that in-vessel retention is feasible when in-vessel injection is initiated within a relatively short time frame under the simulation condition used in the present study

Evaluation for In-Vessel Retention Capabilities with In-Vessel Injection and External Reactor Vessel Cooling

Energy Technology Data Exchange (ETDEWEB)

Lee, Jeong Seong; Ryu, In Chul; Moon, Young Tae [KEPCO Engineering and Construction Co. Ltd., Deajeon (Korea, Republic of)

2016-10-15

If the accident has not progressed to the point of substantial changes in the core geometry, establishing adequate cooling is as straightforward as re-establishing flow through the reactor core. However, if the accident has progressed to the point where the core geometry is substantially altered as a result of material melting and relocation, as was the case in the TMI-2 accident, the means of cooling the debris are not as straightforward. From this time on, the reactor core was either completely or nearly covered by water, with high pressure injection flow initiated shortly after three hours into the accident. However, the core debris was not coolable in this configuration and a substantial quantity of molten core material drained into the bypass region, with approximately twenty metric tons of molten debris draining into the reactor pressure vessel (RPV) lower head. Hence, the core configuration developed at approximately three hours into the accident was not coolable, even submerged in water. The purpose of this paper is to evaluate in-vessel retention capabilities with in-vessel injection (IVI) and external reactor vessel cooling (ERVC) available in a reactor application by using the integrated severe accident analysis code. The MAAP5 models were improved to facilitate evaluation of the in-vessel retention capability of APR1400. In-vessel retention capabilities have been analyzed for the APR1400 using the MAAP5.03 code. The results show that in-vessel retention is feasible when in-vessel injection is initiated within a relatively short time frame under the simulation condition used in the present study.

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.

15 CFR 762.6 - Period of retention.

Science.gov (United States)

2010-01-01

... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Period of retention. 762.6 Section 762.6 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS RECORDKEEPING...

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%.

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

Prediction of retention in micellar electrokinetic chromatography based on molecular structural descriptors by using the heuristic method

International Nuclear Information System (INIS)

Liu Huanxiang; Yao Xiaojun; Liu Mancang; Hu Zhide; Fan Botao

2006-01-01

Based on calculated molecular descriptors from the solutes' structure alone, the micelle-water partition coefficients of 103 solutes in micellar electrokinetic chromatography (MEKC) were predicted using the heuristic method (HM). At the same time, in order to show the influence of different molecular descriptors on the micelle-water partition of solute and to well understand the retention mechanism in MEKC, HM was used to build several multivariable linear models using different numbers of molecular descriptors. The best 6-parameter model gave the following results: the square of correlation coefficient R 2 was 0.958 and the mean relative error was 3.98%, which proved that the predictive values were in good agreement with the experimental results. From the built model, it can be concluded that the hydrophobic, H-bond, polar interactions of solutes with the micellar and aqueous phases are the main factors that determine their partitioning behavior. In addition, this paper provided a simple, fast and effective method for predicting the retention of the solutes in MEKC from their structures and gave some insight into structural features related to the retention of the solutes

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.

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 ...

Retention in methadone maintenance treatment in mainland China, 2004-2012: a literature review.

Science.gov (United States)

Zhou, Kaina; Zhuang, Guihua

2014-01-01

Methadone maintenance treatment (MMT) was implemented in mainland China since 2004. Numerous individual studies have investigated MMT retention but the overview still remains unclear. The aim of the study was to review MMT retention rates and predicting factors in mainland China during 2004-2012. Chinese and English databases of literature were searched for studies reporting on retention rates and predicting factors in non-transfer MMT patients of fixed-site clinics in mainland China (2004-2012). Qualitative methods were used to synthesize the results. Nineteen studies were eligible for review, with sample size ranging from 29 to 3758. Retention rates varied between 30.0% at 6 months in Shanghai and 70.3% at 12 months in Xi'an. Predicting factors were non-treatment including sociodemographics (n=14), support system and social function (n=9), economic status (n=2) and psychological status (n=1), and treatment-related including drug use (n=15), methadone use (n=12), MMT clinics (n=9), MMT participation (n=7), awareness on MMT (n=5) and HIV serostatus (n=3). Methadone dose (n=12) and age (n=7) were the first two important specific factors. In mainland China, MMT retention rates are heterogeneous and relatively lower, and predicting factors mainly focus on objective aspects. Future work should further explore subjective predicting factors regarding MMT retention. © 2013.

Retention of fundamental surgical skills learned in robot-assisted surgery.

Science.gov (United States)

Suh, Irene H; Mukherjee, Mukul; Shah, Bhavin C; Oleynikov, Dmitry; Siu, Ka-Chun

2012-12-01

Evaluation of the learning curve for robotic surgery has shown reduced errors and decreased task completion and training times compared with regular laparoscopic surgery. However, most training evaluations of robotic surgery have only addressed short-term retention after the completion of training. Our goal was to investigate the amount of surgical skills retained after 3 months of training with the da Vinci™ Surgical System. Seven medical students without any surgical experience were recruited. Participants were trained with a 4-day training program of robotic surgical skills and underwent a series of retention tests at 1 day, 1 week, 1 month, and 3 months post-training. Data analysis included time to task completion, speed, distance traveled, and movement curvature by the instrument tip. Performance of the participants was graded using the modified Objective Structured Assessment of Technical Skills (OSATS) for robotic surgery. Participants filled out a survey after each training session by answering a set of questions. Time to task completion and the movement curvature was decreased from pre- to post-training and the performance was retained at all the corresponding retention periods: 1 day, 1 week, 1 month, and 3 months. The modified OSATS showed improvement from pre-test to post-test and this improvement was maintained during all the retention periods. Participants increased in self-confidence and mastery in performing robotic surgical tasks after training. Our novel comprehensive training program improved robot-assisted surgical performance and learning. All trainees retained their fundamental surgical skills for 3 months after receiving the training program.

Retention interval affects visual short-term memory encoding.

Science.gov (United States)

Bankó, Eva M; Vidnyánszky, Zoltán

2010-03-01

Humans can efficiently store fine-detailed facial emotional information in visual short-term memory for several seconds. However, an unresolved question is whether the same neural mechanisms underlie high-fidelity short-term memory for emotional expressions at different retention intervals. Here we show that retention interval affects the neural processes of short-term memory encoding using a delayed facial emotion discrimination task. The early sensory P100 component of the event-related potentials (ERP) was larger in the 1-s interstimulus interval (ISI) condition than in the 6-s ISI condition, whereas the face-specific N170 component was larger in the longer ISI condition. Furthermore, the memory-related late P3b component of the ERP responses was also modulated by retention interval: it was reduced in the 1-s ISI as compared with the 6-s condition. The present findings cannot be explained based on differences in sensory processing demands or overall task difficulty because there was no difference in the stimulus information and subjects' performance between the two different ISI conditions. These results reveal that encoding processes underlying high-precision short-term memory for facial emotional expressions are modulated depending on whether information has to be stored for one or for several seconds.

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.

Electrophysiological correlates of the retention of tones differing in timbre in auditory short-term memory.

Science.gov (United States)

Nolden, Sophie; Bermudez, Patrick; Alunni-Menichini, Kristelle; Lefebvre, Christine; Grimault, Stephan; Jolicoeur, Pierre

2013-11-01

We examined the electrophysiological correlates of retention in auditory short-term memory (ASTM) for sequences of one, two, or three tones differing in timbre but having the same pitch. We focused on event-related potentials (ERPs) during the retention interval and revealed a sustained fronto-central ERP component (most likely a sustained anterior negativity; SAN) that became more negative as memory load increased. Our results are consistent with recent ERP studies on the retention of pitch and suggest that the SAN reflects brain activity mediating the low-level retention of basic acoustic features in ASTM. The present work shows that the retention of timbre shares common features with the retention of pitch, hence supporting the notion that the retention of basic sensory features is an active process that recruits modality-specific brain areas. © 2013 Elsevier Ltd. All rights reserved.

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.

Psychogenic Urinary Retention in Children: A Case Report

Directory of Open Access Journals (Sweden)

Kong-Sang Wan

2010-10-01

Full Text Available Psychogenic urinary retention occurs relatively infrequently in children and is less common than in adults. The influence of psychogenic factors on voiding generally results in an irritative syndrome, but rarely in urinary retention. A definitive diagnosis is established by excluding other pathological conditions. Evaluation includes urine culture, renal echography, spine magnetic resonance imaging, voiding cysto-urethrography, intravenous pyelography, and uroflowmetry. Here, we report on a 6-year-old girl with a 1-month history of voiding difficulty. Urology studies, including urine culture, revealed Escherichia coli, which was not present in preadmission urine cultures. Renal ultrasound and radiological images showed no gross abnormalities or vesicoureteral reflux, but uroflowmetry showed a low flow rate with residual urine. The results of imaging studies and pediatric psychiatric consultation led to a diagnosis of psychogenic urinary retention combined with urinary tract infection. Urinary rehabilitation included intermittent catheterization, bladder training, and supportive psychotherapy, after which the patient recovered and was discharged.

Urinary retention and post-void residual urine in men: separating truth from tradition.

Science.gov (United States)

Kaplan, Steven A; Wein, Alan J; Staskin, David R; Roehrborn, Claus G; Steers, William D

2008-07-01

The definitions of acute and chronic urinary retention remain empirical and subject to wide interpretation. Standardized criteria have not been established and many questions remain unanswered. Moreover, the definition of significant post-void residual urine is unclear. We reviewed several aspects of urinary retention that require clarification with the objective of stimulating discussion among urologists to establish an accurate and coherent definition of urinary retention and significant post-void residual urine, and clarify risk factors. A MEDLINE search for articles written in English and published before April 2007 was done using a list of terms related to urinary retention. Articles not directly relevant to urinary retention or post-void residual urine were excluded. The term urinary retention lacks precise clinical or urodynamic meaning. Use of this term to describe a symptom, a sign, and a condition further complicates the issue. Many factors can contribute to the development of retention, including bladder outlet obstruction, detrusor underactivity, and neurogenic bladder conditions. Community based studies and clinical trials in patients with benign prostatic enlargement and/or lower urinary tract symptoms yield different estimates of the incidence of retention and only provide information on the epidemiology of acute urinary retention. However, age, previous retention episodes, lower urinary tract symptoms, chronic inflammation, serum prostate specific antigen level, prostate size, and urodynamic variables appear to be predictors of acute urinary retention. Alpha-receptor antagonists and 5alpha-reductase inhibitors may be useful in preventing urinary retention episodes and progressive benign prostatic enlargement. Clinical trials on the short-term use of antimuscarinics have not provided evidence that these agents increase the risk of retention; data on longer term administration are needed. Clinicians are adopting less invasive approaches (eg

Relational time in physics

International Nuclear Information System (INIS)

Assis, A.K.T.

2011-01-01

Full text: Isaac Newton (1642-1727) defended in his book Mathematical Principles of Natural Philosophy, also know as Principia, published in 1687, the utilization of absolute time in physics. According to him 'absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external'. Leibniz (1646-1716), on the other hand, was against this concept and proposed relative time to replace it: 'As for my opinion, I have said more than once, that I hold space to be something merely relative, as time is; that I hold it to be an order of coexistence, as time is an order of successions'. Leibniz ideas were accepted and developed by Ernst Mach (1838-1916) in his book The Science of Mechanics, published in 1883. In this work we consider the implementation of relational time, as proposed by Leibniz and Mach, and the consequences this implementation will mean for physics as a whole. We consider some specific examples related to mechanics (Newton's bucket experiment, the flattening of the Earth, Foucault's pendulum experiment) and to electromagnetism (Ampere's force between current carrying wires, an electric charge describing a Larmor radius due to a nearby large magnet, two charges orbiting around one another). We generalize these ideas considering the principle of physical proportions (PPP), according to which no absolute magnitudes should appear in the laws of physics. We present some laws satisfying this principle and others which do not comply with it. The laws which do not satisfy the PPP should be based upon incomplete theories. We present the consequences of complete theories complying with this fundamental principle of nature. (author)

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.

Relative Effectiveness of Computer-Supported Jigsaw II, STAD and TAI Cooperative Learning Strategies on Performance, Attitude, and Retention of Secondary School Students in Physics

Science.gov (United States)

Gambari, Amosa Isiaka; Yusuf, Mudasiru Olalere

2017-01-01

This study investigated the relative effectiveness of computer-supported cooperative learning strategies on the performance, attitudes, and retention of secondary school students in physics. A purposive sampling technique was used to select four senior secondary schools from Minna, Nigeria. The students were allocated to one of four groups:…

Soil Water Retention and Relative Permeability for Conditions from Oven-Dry to Full Saturation

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z. F.

2011-11-04

Common conceptual models for unsaturated flow often rely on the oversimplified representation of medium pores as a bundle of cylindrical capillaries and assume that the matric potential is attributed to the capillary force only. The adsorptive surface forces are ignored. It is often assumed that aqueous flow is negligible when a soil is near or at the residual water content. These models are successful at high and medium water contents but often give poor results at low water contents. These models do not apply to conditions at which the water content is less than the residual water content. We extend the lower bound of existing water-retention functions and conductivity models from residual water content to the oven-dry condition (i.e., zero water content) by defining a state-dependent, residual-water content for a soil drier than a critical value. Furthermore, a hydraulic conductivity model for smooth uniform spheres was modified by introducing a correction factor to describe the film flow-induced hydraulic conductivity for natural porous media. The total unsaturated hydraulic conductivity is the sum of those due to capillary and film flow. The extended retention and conductivity models were verified measurements. Results show that, when the soil is at high and intermediate water content, there is no difference between the un-extended and the extended models; when the soil is at low water content, the un-extended models overestimate the water content but underestimate the conductivity. The extended models match the retention and conductivity measurements well.

Cigarette smoke retention and bronchodilation in patients with COPD. A controlled randomized trial.

Science.gov (United States)

van Dijk, Wouter D; Heijdra, Yvonne; Lenders, Jacques W M; Klerx, Walther; Akkermans, Reinier; van der Pouw, Anouschka; van Weel, Chris; Scheepers, Paul T J; Schermer, Tjard R J

2013-01-01

Bronchodilators are the cornerstone for symptomatic treatment of chronic obstructive pulmonary disease (COPD). Many patients use these agents while persisting in their habit of cigarette smoking. We hypothesized that bronchodilators increase pulmonary retention of cigarette smoke and hence the risk of smoking-related (cardiovascular) disease. Our aim was to investigate if bronchodilation causes increased pulmonary retention of cigarette smoke in patients with COPD. A double-blinded, placebo-controlled, randomized crossover trial, in which COPD patients smoked cigarettes during undilated conditions at one session and maximal bronchodilated conditions at the other session. Co-primary outcomes were pulmonary tar and nicotine retention. We performed a secondary analysis that excludes errors due to possible contamination. Secondary outcomes included the biomarkers C-reactive protein and fibrinogen, and smoke inhalation patterns. Of 39 randomized patients, 35 patients completed the experiment and were included in the final analysis. Bronchodilation did not significantly increase tar retention (-4.5%, p = 0.20) or nicotine retention (-2.6%, p = 0.11). Secondary analysis revealed a potential reduction of retention due to bronchodilation: tar retention (-3.8%, p = 0.13), and nicotine retention (-3.4%, p = 0.01). Bronchodilation did not modify our secondary outcomes. Our results do not support the hypothesis that cigarette tar and nicotine retention in COPD patients is increased by bronchodilation, whereas we observed a possibility towards less retention. www.clinicaltrials.gov: NCT00981851. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

Sexual differences in the distribution and retention of organic and inorganic mercury in methyl mercury-treated rats

International Nuclear Information System (INIS)

Thomas, D.J.; Fisher, H.L.; Sumler, M.R.; Marcus, A.H.; Mushak, P.; Hall, L.L.

1986-01-01

At 56 days of age, male and female Long-Evans rats received 1 μmole of 203 Hg-labeled mercuric chloride per kilogram sc and total, organic, and inorganic mercury contents and concentrations in tissues were determined for up to 98 days postdosing. When expressed on a concentration basis, the only significant sexual difference was in the higher average concentration of organic mercury in the kidneys of females. When expressed on a tissue content basis, significant male-female differences in the kinetics (sex x time interactions) of organic mercury retention were found in kidney, brain, skeletal muscle, pelt, and whole body. Significant sex x time interactions in the concentrations of organic mercury were found in kidney, skeletal muscle, and whole body. Kinetics of retention and concentration of inorganic Hg in the pelt differed significantly for males and females. Discordance of degree of statistical significance of differences in mercury contents and concentrations reflected in part differences in relative body composition of males and females. Differences in integrated exposure were estimated by the female-to-male ratio of areas under retention curves. Reconstruction of whole body organic and inorganic mercury burdens from constituent tissues indicated that integrated exposures of males and females to inorganic mercury were equal but females had a lower integrated exposure to organic mercury. Integrated exposure of liver to either form of mercury was about equal in males and females. However, the integrated exposure of the brain of females to inorganic mercury was 2.19 times that of males suggest'ing a sexual difference in accumulation or retention of inorganic mercury in the nervous system

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.

Relational time in physics

Energy Technology Data Exchange (ETDEWEB)

Assis, A.K.T. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

2011-07-01

Full text: Isaac Newton (1642-1727) defended in his book Mathematical Principles of Natural Philosophy, also know as Principia, published in 1687, the utilization of absolute time in physics. According to him 'absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external'. Leibniz (1646-1716), on the other hand, was against this concept and proposed relative time to replace it: 'As for my opinion, I have said more than once, that I hold space to be something merely relative, as time is; that I hold it to be an order of coexistence, as time is an order of successions'. Leibniz ideas were accepted and developed by Ernst Mach (1838-1916) in his book The Science of Mechanics, published in 1883. In this work we consider the implementation of relational time, as proposed by Leibniz and Mach, and the consequences this implementation will mean for physics as a whole. We consider some specific examples related to mechanics (Newton's bucket experiment, the flattening of the Earth, Foucault's pendulum experiment) and to electromagnetism (Ampere's force between current carrying wires, an electric charge describing a Larmor radius due to a nearby large magnet, two charges orbiting around one another). We generalize these ideas considering the principle of physical proportions (PPP), according to which no absolute magnitudes should appear in the laws of physics. We present some laws satisfying this principle and others which do not comply with it. The laws which do not satisfy the PPP should be based upon incomplete theories. We present the consequences of complete theories complying with this fundamental principle of nature. (author)

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...

Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

Energy Technology Data Exchange (ETDEWEB)

Bai, Yuanyuan; Xiang, Feng; Wang, Hong, E-mail: hwang@mail.xjtu.edu.cn, E-mail: suo@seas.harvard.edu [Electronic Materials Research Laboratory, School of Electronics and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, Baohong; Zhou, Jinxiong [State Key Laboratory for Strength and Vibration of Mechanical Structures, International Center for Applied Mechanics and School of Aerospace, Xi' an Jiaotong University, Xi' an 710049 (China); Suo, Zhigang, E-mail: hwang@mail.xjtu.edu.cn, E-mail: suo@seas.harvard.edu [School of Engineering and Applied Sciences, Kavli Institute of Bionano Science and Technology, Harvard University, Cambridge, Massachusetts 02138 (United States)

2014-10-13

Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels become possible.

Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

International Nuclear Information System (INIS)

Bai, Yuanyuan; Xiang, Feng; Wang, Hong; Chen, Baohong; Zhou, Jinxiong; Suo, Zhigang

2014-01-01

Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels become possible.

Charge retention characteristics of (Bi,La)4Ti3O12 capacitors : comparison with Pb(Zr,Ti)O3 capacitors

International Nuclear Information System (INIS)

Yoon, J. G.; Kim, D. J.; So, Y. W.

2005-01-01

We investigated the retention characteristics of (Bi,La) 4 Ti 3 O 12 (BLT) capacitors with Pt electrodes and compared them with Pb(Zr,Ti)O 3 (PZT) capacitors in the same- and opposite-state retentions. Polarization relaxations in short-time regime (t < 100 s) were well described by a power-law decay function, but the polarization relaxation of BLT was more significant than that of PZT. We discuss the difference in the relaxation process of polarization in conjunction with film microstructures and magnitudes of polarization for BLT and PZT. In long-time opposite-state retention, BLT capacitors showed much better characteristics than PZT. For both BLT and PZT, the opposite-state retention loss was governed by the development of an internal field during retention. For BLT capacitors, internal field development was much weaker than for PZT after retention, resulting in a good opposite-state retention. Structural and electrical properties are discussed in conjunction with the retention characteristics of the materials.

[Mucoceles of the minor salivary glands. Extravasation mucoceles (mucus granulomas) and retention mucoceles (mucus retention cysts) (author's transl)].

Science.gov (United States)

Seifert, G; Donath, K; von Gumberz, C

1981-06-01

. Partial obstructions of the ducts are considered as the important factor in the development of the retention mucocele. Besides, relations are discussed to high differentiated monomorphic adenomas. 9. In differential diagnosis, the retention mucoceles must be distinguished from other salivary glands cysts (lymphoepithelial cysts etc.), the extravasation mucoceles from other granulomatous reactions of the salivary glands.

External and Internal Barriers to Studying Can Affect Student Success and Retention in a Diverse Classroom

Directory of Open Access Journals (Sweden)

Laurence Clement

2016-12-01

Full Text Available Although a majority of under-represented minority (URM students begin their postsecondary education at community colleges, little is known about barriers to success and retention for transfer-bound science students. This study focuses on some of the barriers that affect these students’ ability to study adequately for a community college “gateway” course. It tests whether instructors’ expectations of study time were realistic for community college students and whether students reported facing external barriers, such as job and family responsibilities, or internal barriers to studying, such as lack of motivational, cognitive, and metacognitive abilities, all of which have been shown to impact academic success and retention. It also tests whether students who faced such barriers were less likely to succeed in and complete the course, as well as whether time spent studying was related to course success. The findings reported here show that community college students do not have enough available time to study and that external and internal barriers are both prevalent among these students. In addition, students who faced such barriers are more likely to fail or drop the class. Results also show that study time is positively correlated with retention, but not performance, as well as with some motivational, cognitive, and metacognitive dimensions of self-regulated learning. These findings lead to new questions, including whether student success in a community college class is associated with the use of cognitive and metacognitive learning strategies for students with no prior degrees, and whether increased course structure may improve success for college students with lower self-regulated abilities.

Deuterium in-vessel retention characterisation through the use of particle balance on Tore Supra

International Nuclear Information System (INIS)

Bucalossi, J.; Brosset, C.; Pegourie, B.; Tsitrone, E.; Dufour, E.; Eckedahl, A.; Geraud, A.; Goniche, M.; Gunn, J.; Loarer, T.; Monier-Garbet, P.; Vallet, J.C.; Vartanian, S.

2007-01-01

Fuel retention inside plasma facing components will be a crucial issue not only in fusion reactors of the future, but also in ITER. The estimation of the fraction of the fuel which remains trapped inside the vessel is quite a difficult task. Particle balance analysis provides information for the whole vacuum chamber as a function of time and can be use to monitor the tritium in-vessel retention in real-time. On Tore Supra with a careful choice and position of pressure sensors, proper calibration procedures, the accuracy of the balance is around 10%. Particle balance analysis have been performed on many long pulse discharges and deuterium in-vessel retention has been found to be a constant around 5 x 10 20 D/s after several minutes of plasma. The evolution of the retention rate with plasma parameters indicates that deuterium bulk implantation and diffusion could dominate codeposition with carbon atoms. Particle balance is a powerful tool that should be implemented in ITER

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.

Influence of particle flux density and temperature on surface modifications of tungsten and deuterium retention

International Nuclear Information System (INIS)

Buzi, Luxherta; Temmerman, Greg De; Unterberg, Bernhard; Reinhart, Michael; Litnovsky, Andrey; Philipps, Volker; Oost, Guido Van; Möller, Sören

2014-01-01

Systematic study of deuterium irradiation effects on tungsten was done under ITER – relevant high particle flux density, scanning a broad surface temperature range. Polycrystalline ITER – like grade tungsten samples were exposed in linear plasma devices to two different ranges of deuterium ion flux densities (high: 3.5–7 · 10 23 D + /m 2 s and low: 9 · 10 21 D + /m 2 s). Particle fluence and ion energy, respectively 10 26 D + /m 2 and ∼38 eV were kept constant in all cases. The experiments were performed at three different surface temperatures 530 K, 630 K and 870 K. Experimental results concerning the deuterium retention and surface modifications of low flux exposure confirmed previous investigations. At temperatures 530 K and 630 K, deuterium retention was higher at lower flux density due to the longer exposure time (steady state plasma operation) and a consequently deeper diffusion range. At 870 K, deuterium retention was found to be higher at high flux density according to the thermal desorption spectroscopy (TDS) measurements. While blisters were completely absent at low flux density, small blisters of about 40–50 nm were formed at high flux density exposure. At the given conditions, a relation between deuterium retention and blister formation has been found which has to be considered in addition to deuterium trapping in defects populated by diffusion

Retention and effective diffusion of model metabolites on porous graphitic carbon.

Science.gov (United States)

Lunn, Daniel B; Yun, Young J; Jorgenson, James W

2017-12-29

The study of metabolites in biological samples is of high interest for a wide range of biological and pharmaceutical applications. Reversed phase liquid chromatography is a common technique used for the separation of metabolites, but it provides little retention for polar metabolites. An alternative to C18 bonded phases, porous graphitic carbon has the ability to provide significant retention for both non-polar and polar analytes. The goal of this work is to study the retention and effective diffusion properties of porous graphitic carbon, to see if it is suitable for the wide injection bands and long run times associated with long, packed capillary-scale separations. The retention of a set of standard metabolites was studied for both stationary phases over a wide range of mobile phase conditions. This data showed that porous graphitic carbon benefits from significantly increased retention (often >100 fold) under initial gradient conditions for these metabolites, suggesting much improved ability to focus a wide injection band at the column inlet. The effective diffusion properties of these columns were studied using peak-parking experiments with the standard metabolites under a wide range of retention conditions. Under the high retention conditions, which can be associated with retention after injection loading for gradient separations, D eff /D m ∼0.1 for both the C18-bonded and porous graphitic carbon columns. As C18 bonded particles are widely, and successfully utilized for long gradient separations without issue of increasing peak width from longitudinal diffusion, this suggests that porous graphitic carbon should be amenable for long runtime gradient separations as well. Copyright © 2017 Elsevier B.V. All rights reserved.

The influence of secondary conditions on job acquisition and retention in adults with spinal cord injury.

Science.gov (United States)

Meade, Michelle A; Forchheimer, Martin B; Krause, James S; Charlifue, Susan

2011-03-01

To examine the associations of job acquisition and job retention to secondary conditions, hospitalizations, and nursing home stays for adults with spinal cord injury (SCI). Retrospective analysis of longitudinal data from multicenter study. Community setting. Two samples of adults participating in the SCI Model Systems; the first sample consisted of persons who reported being unemployed at follow-up (n=9501); the second sample consisted of those who reported working at follow-up (n=5,150). Not applicable. Job acquisition (change from not working at 1 anniversary of injury to working at the following data collection) and job retention (maintenance of work between 2 assessment periods). Discrete time hazard modeling was used to assess how secondary conditions affect job acquisition. After controlling for the effects of demographic and injury characteristics, hospitalizations within the last 12 months were associated with decreased chance of having obtained employment. Hierarchic logistic regression analyses were used to examine job retention. Hospitalizations and the presence of PUs were associated with lower odds of job retention once demographic and injury characteristics were controlled. Secondary conditions from the previous assessment period were not significantly related to either job acquisition or job retention after the variance from demographic and injury characteristics and current secondary conditions were controlled. Hospitalization, as well as a limited number of secondary conditions, were associated with reduced odds of both job acquisition and job retention among adults with SCI. Interventions that can prevent secondary conditions and reduce the need for hospitalizations may be beneficial in improving employment for this population. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Injuries from non-retention in gillnet fisheries suppress reproductive maturation in escaped fish.

Science.gov (United States)

Baker, Matthew R; Swanson, Penny; Young, Graham

2013-01-01

Exploitation of fisheries resources has unintended consequences, not only in the bycatch and discard of non-target organisms, but also in damage to targeted fish that are injured by gear but not landed (non-retention). Delayed mortality due to non-retention represents lost reproductive potential in exploited stocks, while not contributing to harvest. Our study examined the physiological mechanisms by which delayed mortality occurs and the extent to which injuries related to disentanglement from commercial gear compromise reproductive success in spawning stocks of Pacific salmon (Oncorhynchus spp.). We found evidence for elevated stress in fish injured via non-retention in gillnet fisheries. Plasma cortisol levels correlated with the severity of disentanglement injury and were elevated in fish that developed infections related to disentanglement injuries. We also analyzed sex steroid concentrations in females (estradiol-17β and 17,20β-dihydroxy-4-pregnen-3-one) to determine whether non-retention impairs reproductive potential in escaped individuals. We demonstrate evidence for delayed or inhibited maturation in fish with disentanglement injuries. These findings have important implications for effective conservation and management of exploited fish stocks and suggest means to improve spawning success in such stocks if retention in commercial fisheries is improved and incidental mortality reduced.

Injuries from non-retention in gillnet fisheries suppress reproductive maturation in escaped fish.

Directory of Open Access Journals (Sweden)

Matthew R Baker

Full Text Available Exploitation of fisheries resources has unintended consequences, not only in the bycatch and discard of non-target organisms, but also in damage to targeted fish that are injured by gear but not landed (non-retention. Delayed mortality due to non-retention represents lost reproductive potential in exploited stocks, while not contributing to harvest. Our study examined the physiological mechanisms by which delayed mortality occurs and the extent to which injuries related to disentanglement from commercial gear compromise reproductive success in spawning stocks of Pacific salmon (Oncorhynchus spp.. We found evidence for elevated stress in fish injured via non-retention in gillnet fisheries. Plasma cortisol levels correlated with the severity of disentanglement injury and were elevated in fish that developed infections related to disentanglement injuries. We also analyzed sex steroid concentrations in females (estradiol-17β and 17,20β-dihydroxy-4-pregnen-3-one to determine whether non-retention impairs reproductive potential in escaped individuals. We demonstrate evidence for delayed or inhibited maturation in fish with disentanglement injuries. These findings have important implications for effective conservation and management of exploited fish stocks and suggest means to improve spawning success in such stocks if retention in commercial fisheries is improved and incidental mortality reduced.

The effects of flow-path modification on water-quality constituent retention in an urban stormwater detention pond and wetland system, Orlando, Florida

Science.gov (United States)

Gain, W.S.

1996-01-01

Changes in constituent retention in a wet stormwater-detention pond and wetland system in Orlando, Florida, were evaluated following the 1988 installation of a flow barrier which approximately doubled the flow path and increased detention time in the pond. The pond and wetland were arranged in series so that stormwater first enters the pond and overflows into the wetland before spilling over to the regional stream system. Several principal factors that contribute to constituent retention were examined, including changes in pond-water quality between storms, stormwater quality, and pond-water flushing during storms. A simple, analytical pond-water mixing model was used as the basis for interpreting changes in retention efficiencies caused by pond modification. Retention efficiencies were calculated by a modified event-mean concentration efficiency method using a minimum variance unbiased estimator approach. The results of this study generally support the hypothesis that changes in the geometry of stormwater treatment systems can significantly affect the constituent retention efficiency of the pond and wetland system. However, the results also indicate that these changes in efficiency are caused not only by changes in residence time, but also by changes in stormwater mixing and pond water flushing during storms. Additionally, the use of average efficiencies as indications of treatment effectiveness may fail to account for biases associated with sample distribution and independent physical properties of the system, such as the range and concentrations of constituents in stormwater inflows and stormwater volume. Changes in retention efficiencies varied among chemical constituents and were significantly different in the pond and wetland. Retention efficiency was related to inflow concentration for most constituents. Increased flushing of the pond after modification caused decreases in retention efficiencies for constituents that concentrate in the pond between storms

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.

Linking local retention, self-recruitment, and persistence in marine metapopulations

KAUST Repository

Lett, Christophe

2015-08-01

Three indices of larval retention have been used in the literature to assess the tendency for self-maintenance of local marine populations: local retention (LR), self-recruitment (SR), and relative local retention (RLR). Only one of these, LR, defined as the ratio of locally produced settlement to local egg production, has a clear relationship to self-persistence of individual sites. However, SR, the ratio of locally produced settlement to settlement of all origins at a site, is generally easier to measure experimentally. We use theoretical, simulation, and empirical approaches to bridge the gap between these different indices, and demonstrate that there is a proportional relationship between SR and LR for metapopulations close to a stable state and with lifetime egg production (LEP) approximately uniform over space. Similarly, for systems where larval mortality rates are a relatively uniform function of release site, RLR (defined as the ratio of locally produced settlement to all settlement of local origin) and LR will also be proportional. Therefore, SR and RLR provide information on relative rates of LR for systems satisfying these conditions. Furthermore, the ratio between LR and SR can be used to evaluate global persistence of metapopulations, and therefore provides valuable information not necessarily available if only LR is considered.

A Low Leakage Autonomous Data Retention Flip-Flop with Power Gating Technique

Directory of Open Access Journals (Sweden)

Xiaohui Fan

2014-01-01

Full Text Available With the scaling of technology process, leakage power becomes an increasing portion of total power. Power gating technology is an effective method to suppress the leakage power in VLSI design. When the power gating technique is applied in sequential circuits, such as flip-flops and latches, the data retention is necessary to store the circuit states. A low leakage autonomous data retention flip-flop (ADR-FF is proposed in this paper. Two high-Vth transistors are utilized to reduce the leakage power consumption in the sleep mode. The data retention cell is composed of a pair of always powered cross-coupled inverters in the slave latch. No extra control signals and complex operations are needed for controlling the data retention and restoration. The data retention flip-flops are simulated with NCSU 45 nm technology. The postlayout simulation results show that the leakage power of the ADR-FF reduces 51.39% compared with the Mutoh-FF. The active power of the ADR-FF is almost equal to other data retention flip-flops. The average state mode transition time of ADR-FF decreases 55.98%, 51.35%, and 21.07% as compared with Mutoh-FF, Balloon-FF, and Memory-TG-FF, respectively. Furthermore, the area overhead of ADR-FF is smaller than other data retention flip-flops.

Color Functions in Information Perception and Retention

Science.gov (United States)

Tolliver, Don L.

1973-01-01

This paper reviews research findings related to color and how it affects perception and retention of information. From the literature it appears colors have varying degrees of value as cues or aids to memory of stimulus information and difference appears to exist between colors as they interact in informational materials. (21 references)…

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

Employee Retention Strategies : the case of a patent firm in Australia

OpenAIRE

Ahmad, Khalid; Azumah, Kenneth

2012-01-01

Retaining employees is an important goal of every organization. This thesis explores the factors that can significantly impact employee retention in an organisation. It attempts to relate some of the factors discovered to major theories such as the Employee Equity Model, Herzberg’s (Two-Factor) Theory and the Job Embeddedness Theory. The literature surveyed by this study mention employee motivation, job satisfaction and job embeddedness as the main factors that influence employee retention ra...

A Reinforcement-Based Learning Paradigm Increases Anatomical Learning and Retention-A Neuroeducation Study.

Science.gov (United States)

Anderson, Sarah J; Hecker, Kent G; Krigolson, Olave E; Jamniczky, Heather A

2018-01-01

In anatomy education, a key hurdle to engaging in higher-level discussion in the classroom is recognizing and understanding the extensive terminology used to identify and describe anatomical structures. Given the time-limited classroom environment, seeking methods to impart this foundational knowledge to students in an efficient manner is essential. Just-in-Time Teaching (JiTT) methods incorporate pre-class exercises (typically online) meant to establish foundational knowledge in novice learners so subsequent instructor-led sessions can focus on deeper, more complex concepts. Determining how best do we design and assess pre-class exercises requires a detailed examination of learning and retention in an applied educational context. Here we used electroencephalography (EEG) as a quantitative dependent variable to track learning and examine the efficacy of JiTT activities to teach anatomy. Specifically, we examined changes in the amplitude of the N250 and reward positivity event-related brain potential (ERP) components alongside behavioral performance as novice students participated in a series of computerized reinforcement-based learning modules to teach neuroanatomical structures. We found that as students learned to identify anatomical structures, the amplitude of the N250 increased and reward positivity amplitude decreased in response to positive feedback. Both on a retention and transfer exercise when learners successfully remembered and translated their knowledge to novel images, the amplitude of the reward positivity remained decreased compared to early learning. Our findings suggest ERPs can be used as a tool to track learning, retention, and transfer of knowledge and that employing the reinforcement learning paradigm is an effective educational approach for developing anatomical expertise.

Factors affecting de novo urinary retention after Holmium laser enucleation of the prostate.

Directory of Open Access Journals (Sweden)

Sung Han Kim

Full Text Available OBJECTIVE: Patients can experience urinary retention (UR after Holmium laser enucleation of the prostate (HoLEP that requires bladder distension during the procedure. The aim of this retrospective study is to identify factors affecting the UR after HoLEP. MATERIALS AND METHODS: 336 patients, which underwent HoLEP for a symptomatic benign prostatic hyperplasia between July 2008 and March 2012, were included in this study. Urethral catheters were routinely removed one or two days after surgery. UR was defined as the need for an indwelling catheter placement following a failure to void after catheter removal. Demographic and clinical parameters were compared between the UR (n = 37 and the non-urinary retention (non-UR; n = 299 groups. RESULTS: The mean age of patients was 68.3 (±6.5 years and the mean operative time was 75.3 (±37.4 min. Thirty seven patients (11.0% experienced a postoperative UR. UR patients voided catheter free an average of 1.9 (±1.7 days after UR. With regard to the causes of UR, 24 (7.1% and 13 (3.9% patients experienced a blood clot-related UR and a non-clot related UR respectively. Using multivariate analysis (p0.05. CONCLUSIONS: De novo UR after HoLEP was found to be self-limited and it was not related to learning curve, patient age, diabetes, or operative time. Efficient morcellation and careful control of bleeding, which reduces clot formation, decrease the risk of UR after HoLEP.

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.

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

Phosphorus retention in a newly constructed wetland receiving agricultural tile drainage water.

Science.gov (United States)

Kynkäänniemi, Pia; Ulén, Barbro; Torstensson, Gunnar; Tonderski, Karin S

2013-01-01

One measure used in Sweden to mitigate eutrophication of waters is the construction of small wetlands (free water surface wetland for phosphorus retention [P wetlands]) to trap particulate phosphorus (PP) transported in ditches and streams. This study evaluated P retention dynamics in a newly constructed P wetland serving a 26-ha agricultural catchment with clay soil. Flow-proportional composite water samples were collected at the wetland inlet and outlet over 2 yr (2010-2011) and analyzed for total P (TP), dissolved P (DP), particulate P (PP), and total suspended solids (TSS). Both winters had unusually long periods of snow accumulation, and additional time-proportional water samples were frequently collected during snowmelt. Inflow TP and DP concentrations varied greatly (0.02-1.09 mg L) during the sampling period. During snowmelt in 2010, there was a daily oscillation in P concentration and water flow in line with air temperature variations. Outflow P concentrations were generally lower than inflow concentrations, with net P losses observed only in August and December 2010. On an annual basis, the wetland acted as a net P sink, with mean specific retention of 69 kg TP, 17 kg DP, and 30 t TSS ha yr, corresponding to a reduction in losses of 0.22 kg TP ha yr from the agricultural catchment. Relative retention was high (36% TP, 9% DP, and 36% TSS), indicating that small constructed wetlands (0.3% of catchment area) can substantially reduce P loads from agricultural clay soils with moderately undulating topography. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Therapeutic Alliance and Retention in Brief Strategic Family Therapy: A Mixed-Methods Study.

Science.gov (United States)

Sheehan, Alyson H; Friedlander, Myrna L

2015-10-01

We explored how the therapeutic alliance contributed to retention in Brief Strategic Family Therapy by analyzing videotapes of eight-first sessions in which four therapists worked with one family that stayed in treatment and one family that dropped out. Although behavioral exchange patterns between clients and therapists did not differ by retention status, positive therapist alliance-related behavior followed negative client alliance behavior somewhat more frequently in the retained cases. In the qualitative aspect of the study, four family therapy experts each viewed two randomly assigned sessions and commented on their quality without knowing the families' retention status. A qualitative analysis of the audiotaped commentaries revealed 18 alliance-related themes that were more characteristic of either the retained or the nonretained cases. © 2015 American Association for Marriage and Family Therapy.

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)

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

Retention/Diffusivity Studies in Free-Surface Flowing Liquid Lithium

International Nuclear Information System (INIS)

R.A. Stubbers; G.H. Miley; M. Nieto; W. Olczak; D.N. Ruzic; A. Hassanein

2004-01-01

FLIRE was designed to measure the hydrogen and helium retention and diffusivity in a flowing stream of liquid lithium, and it has accomplished these goals. Retention coefficients for helium in the flowing liquid stream were 0.1-2% for flow speeds of 44 cm/s and implantation energies between 500 and 2000 eV. The energy dependence of retention is linear for the energy range considered, as expected, and the dependence of retention on flow velocity fits the expected square-root of flow speed dependence. Estimates of the helium diffusion coefficient in the flowing lithium stream were ∼ 4 x 10 -7 cm 2 /s, and are independent of implantation energy. This value is much lower than expected, which could be due to several factors, such as mixing, bubble formation or surface film formation. In the case of hydrogen, long term retention and release mechanisms are of greatest importance, since this relates to tritium inventory in flowing lithium PFCs for fusion applications. The amount of hydride formation was measured for flowing lithium exposed to neutral deuterium gas. Thermal desorption spectroscopy (TDS) measurements indicate that the hydride concentration was between 0.1 and 0.2% over a wide range of pressures (6.5 x 10 -5 to 1 Torr). This result implies that the deuterium absorption rate is limited by the surface dissociation rate, since deuterium (hydrogen/tritium) is absorbed in its atomic form, not its molecular form

Retention/Diffusivity Studies in Free-Surface Flowing Liquid Lithium

Energy Technology Data Exchange (ETDEWEB)

R.A. Stubbers; G.H. Miley; M. Nieto; W. Olczak; D.N. Ruzic; A. Hassanein

2004-12-14

FLIRE was designed to measure the hydrogen and helium retention and diffusivity in a flowing stream of liquid lithium, and it has accomplished these goals. Retention coefficients for helium in the flowing liquid stream were 0.1-2% for flow speeds of 44 cm/s and implantation energies between 500 and 2000 eV. The energy dependence of retention is linear for the energy range considered, as expected, and the dependence of retention on flow velocity fits the expected square-root of flow speed dependence. Estimates of the helium diffusion coefficient in the flowing lithium stream were {approx} 4 x 10{sup -7} cm{sup 2}/s, and are independent of implantation energy. This value is much lower than expected, which could be due to several factors, such as mixing, bubble formation or surface film formation. In the case of hydrogen, long term retention and release mechanisms are of greatest importance, since this relates to tritium inventory in flowing lithium PFCs for fusion applications. The amount of hydride formation was measured for flowing lithium exposed to neutral deuterium gas. Thermal desorption spectroscopy (TDS) measurements indicate that the hydride concentration was between 0.1 and 0.2% over a wide range of pressures (6.5 x 10{sup -5} to 1 Torr). This result implies that the deuterium absorption rate is limited by the surface dissociation rate, since deuterium (hydrogen/tritium) is absorbed in its atomic form, not its molecular form.

Retention of School-Based SLPs: Relationships among Caseload Size, Workload Satisfaction, Job Satisfaction, and Best Practice

Science.gov (United States)

Hutchins, Tiffany L.; Howard, Malinda; Prelock, Patricia A.; Belin, Gayle

2010-01-01

Nationally, the shortage of speech-language pathologists (SLPs) in the schools is growing. As such, it is important to understand factors related to the retention of SLPs in this setting. This study expanded on previous research by examining a wider range of factors that may be related to the retention of SLPs including caseload size, workload…

Whole-body retention studies of /sup 169/Yb-citrate. Estimation of radiation dose to humans from /sup 169/Yb-citrate

Energy Technology Data Exchange (ETDEWEB)

Ando, A; Hiraki, T [Kanazawa Univ. (Japan). School of Paramedicine; Mori, H; Ando, I; Hisada, K

1977-09-01

For purpose of the estimation of the radiation dose to humans from /sup 169/Yb-citrate, the whole-body retention studies using five rats were carried out. Following intravenous administration of /sup 169/Yb-citrate, the whole-body activity was monitored for 40 days by the animal counter. The whole-body retention curve consisted of three components: the first with a 3.6 hours effective half-time, the second with an 154 hours effective half-time and the third with a 29.9 days effective half-time. Therefore it was assumed that 32% of the administered /sup 169/Yb-citrate clears from the kidney with a short biologic half-time (3.6 hours), 18% remains in the liver and other soft tissues with a relatively long biologic half-time (194 hours) and 50% remains in the bone with a long biologic half-time (850 days). Based on these biological data and the MIRD Committee method, the average dose to the bone and whole-body were 20.8 rads/mCi and 4.5 rads/mCi respectively.

Accurate prediction of retention in hydrophilic interaction chromatography by back calculation of high pressure liquid chromatography gradient profiles.

Science.gov (United States)

Wang, Nu; Boswell, Paul G

2017-10-20

Gradient retention times are difficult to project from the underlying retention factor (k) vs. solvent composition (φ) relationships. A major reason for this difficulty is that gradients produced by HPLC pumps are imperfect - gradient delay, gradient dispersion, and solvent mis-proportioning are all difficult to account for in calculations. However, we recently showed that a gradient "back-calculation" methodology can measure these imperfections and take them into account. In RPLC, when the back-calculation methodology was used, error in projected gradient retention times is as low as could be expected based on repeatability in the k vs. φ relationships. HILIC, however, presents a new challenge: the selectivity of HILIC columns drift strongly over time. Retention is repeatable in short time, but selectivity frequently drifts over the course of weeks. In this study, we set out to understand if the issue of selectivity drift can be avoid by doing our experiments quickly, and if there any other factors that make it difficult to predict gradient retention times from isocratic k vs. φ relationships when gradient imperfections are taken into account with the back-calculation methodology. While in past reports, the accuracy of retention projections was >5%, the back-calculation methodology brought our error down to ∼1%. This result was 6-43 times more accurate than projections made using ideal gradients and 3-5 times more accurate than the same retention projections made using offset gradients (i.e., gradients that only took gradient delay into account). Still, the error remained higher in our HILIC projections than in RPLC. Based on the shape of the back-calculated gradients, we suspect the higher error is a result of prominent gradient distortion caused by strong, preferential water uptake from the mobile phase into the stationary phase during the gradient - a factor our model did not properly take into account. It appears that, at least with the stationary phase

22 CFR 226.53 - Retention and access requirements for records.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Retention and access requirements for records. 226.53 Section 226.53 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ADMINISTRATION OF... date of submission of the final expenditure report or, for awards that are renewed quarterly or...

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.

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.

Addressing employee turnover and retention: keeping your valued performers.

Science.gov (United States)

McConnell, Charles R

2011-01-01

Employee turnover and employee retention are inextricably linked; to control turnover is to enhance retention. Turnover is a relatively simple concept; however, considerable confusion often results when addressing turnover because of differences in how it is defined; that is, what is counted, how it is counted, and how the turnover rates are expressed. Turnover is also costly, although not enough attention is paid to its cost because so much of it is indirect and thus not readily visible. There are a variety of causes of turnover, some that can be corrected and some that cannot be avoided. Reducing or otherwise controlling turnover requires continuing management attention to its causes and constant recognition of what can and should be controlled and what cannot be controlled. Ongoing attention to turnover is an essential part of the department manager's role; every improvement in turnover is a direct improvement in retention, with eventual positive effects on the bottom line.

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

Pre-stimulus BOLD-network activation modulates EEG spectral activity during working memory retention

Directory of Open Access Journals (Sweden)

Mara eKottlow

2015-05-01

Full Text Available Working memory (WM processes depend on our momentary mental state and therefore exhibit considerable fluctuations. Here, we investigate the interplay of task-preparatory and task-related brain activity as represented by pre-stimulus BOLD-fluctuations and spectral EEG from the retention periods of a visual WM task. Visual WM is used to maintain sensory information in the brain enabling the performance of cognitive operations and is associated with mental health.We tested 22 subjects simultaneously with EEG and fMRI while performing a visuo-verbal Sternberg task with two different loads, allowing for the temporal separation of preparation, encoding, retention and retrieval periods.Four temporally coherent networks - the default mode network (DMN, the dorsal attention, the right and the left WM network - were extracted from the continuous BOLD data by means of a group ICA. Subsequently, the modulatory effect of these networks’ pre-stimulus activation upon retention-related EEG activity in the theta, alpha and beta frequencies was analyzed. The obtained results are informative in the context of state-dependent information processing.We were able to replicate two well-known load-dependent effects: the frontal-midline theta increase during the task and the decrease of pre-stimulus DMN activity. As our main finding, these two measures seem to depend on each other as the significant negative correlations at frontal-midline channels suggested. Thus, suppressed pre-stimulus DMN levels facilitated later task related frontal midline theta increases. In general, based on previous findings that neuronal coupling in different frequency bands may underlie distinct functions in WM retention, our results suggest that processes reflected by spectral oscillations during retention seem not only to be online synchronized with activity in different attention-related networks but are also modulated by activity in these networks during preparation intervals.

Extensive Management Promotes Plant and Microbial Nitrogen Retention in Temperate Grassland

Science.gov (United States)

de Vries, Franciska T.; Bloem, Jaap; Quirk, Helen; Stevens, Carly J.; Bol, Roland; Bardgett, Richard D.

2012-01-01

Leaching losses of nitrogen (N) from soil and atmospheric N deposition have led to widespread changes in plant community and microbial community composition, but our knowledge of the factors that determine ecosystem N retention is limited. A common feature of extensively managed, species-rich grasslands is that they have fungal-dominated microbial communities, which might reduce soil N losses and increase ecosystem N retention, which is pivotal for pollution mitigation and sustainable food production. However, the mechanisms that underpin improved N retention in extensively managed, species-rich grasslands are unclear. We combined a landscape-scale field study and glasshouse experiment to test how grassland management affects plant and soil N retention. Specifically, we hypothesised that extensively managed, species-rich grasslands of high conservation value would have lower N loss and greater N retention than intensively managed, species-poor grasslands, and that this would be due to a greater immobilisation of N by a more fungal-dominated microbial community. In the field study, we found that extensively managed, species-rich grasslands had lower N leaching losses. Soil inorganic N availability decreased with increasing abundance of fungi relative to bacteria, although the best predictor of soil N leaching was the C/N ratio of aboveground plant biomass. In the associated glasshouse experiment we found that retention of added 15N was greater in extensively than in intensively managed grasslands, which was attributed to a combination of greater root uptake and microbial immobilisation of 15N in the former, and that microbial immobilisation increased with increasing biomass and abundance of fungi. These findings show that grassland management affects mechanisms of N retention in soil through changes in root and microbial uptake of N. Moreover, they support the notion that microbial communities might be the key to improved N retention through tightening linkages

Peptide retention prediction using hydrophilic interaction liquid chromatography coupled to mass spectrometry.

Science.gov (United States)

Badgett, Majors J; Boyes, Barry; Orlando, Ron

2018-02-16

A model that predicts retention for peptides using a HALO ® penta-HILIC column and gradient elution was created. Coefficients for each amino acid were derived using linear regression analysis and these coefficients can be summed to predict the retention of peptides. This model has a high correlation between experimental and predicted retention times (0.946), which is on par with previous RP and HILIC models. External validation of the model was performed using a set of H. pylori samples on the same LC-MS system used to create the model, and the deviation from actual to predicted times was low. Apart from amino acid composition, length and location of amino acid residues on a peptide were examined and two site-specific corrections for hydrophobic residues at the N-terminus as well as hydrophobic residues one spot over from the N-terminus were created. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental study of the retention properties of a cyclo olefin polymer pillar array column in reversed-phase mode.

Science.gov (United States)

Illa, Xavi; De Malsche, Wim; Gardeniers, Han; Desmet, Gert; Romano-Rodríguez, Albert

2010-11-01

Experimental measurements to study the retention capacity and band broadening under retentive conditions using micromachined non-porous pillar array columns fabricated in cyclo olefin polymer are presented. In particular, three columns with different depths but with the same pillar structure have been fabricated via hot embossing and pressure-assisted thermal bonding. Separations of a mixture of four coumarins using varying mobile phase compositions have been monitored to study the relation between the retention factor and the ratio of organic solvent in the aqueous mobile phase. Moreover, the linear relation between the retention and the surface/volume ratio predicted in theory has been observed, achieving retention factors up to k=2.5. Under the same retentive conditions, minimal reduced plate height values of h(min)=0.4 have been obtained at retention factors of k=1.2. These experimental results are compared with the case of non-porous and porous silicon pillars. Similar results for the plate heights are achieved while retention factors are higher than the non-porous silicon column and considerably smaller than the porous pillar column, given the non-porous nature of the used cyclo olefin polymer. The feasibility of using this polymer column as an alternative to the pillar array silicon columns is corroborated.

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

Separation optimization of aniline and seven 4-substituted anilines in high-submicellar liquid chromatography using empirical retention modeling and Derringer's desirability function.

Science.gov (United States)

Hadjmohammadi, Mohammad Reza; S J Nazari, S Saman

2013-08-01

The separation optimization of aniline and seven 4-substituted derivatives in high-submicellar LC was performed using an interpretive optimization strategy and Derringer's desirability function. Description of the retention of solutes was carried out through several hyperbolic and logarithmic retention models using the retention data of five mobile phases of SDS (0.06-0.12 M) and methanol (50-70% v/v) at pH 3. Among the investigated models, a logarithmic retention model logk=c0+c1φ+c2[S]+c12φ[S]+d12(φ[S])0.5 showed the best prediction capability and was used to predict the solute retention factors. A grid search program was used to calculate the retention times of each solute, based on the best retention model, for all combinations of SDS and methanol concentrations in the factor space. Two different chromatographic goals, analysis time and retention differences between adjacent peaks, were evaluated simultaneously using Derringer's desirability function for each mobile phase conditions in the grid search. Optimal mobile phase composition for separation of eight anilines was found to be 0.119 M SDS and 53% v/v methanol. Under these conditions, full resolutions with a reasonable analysis time (22 min) were obtained. At the optimal condition, a good agreement was observed between predicted and experimental values of the retention times. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Scientific method by argumentation design: learning process for maintaining student’s retention

Science.gov (United States)

Siswanto; Yusiran; Asriyadin; Gumilar, S.; Subali, B.

2018-03-01

The purpose of this research describes the effect of scientific methods designed by argumentation in maintaining retention of pre-service physics teachers (students) in mechanical concept. This learning consists of five stages including the first two stages namely observing and questioning. While the next three stages of reasoning, trying, and communicating are made of argumentation design. To know the effectiveness of treatment, students are given pre-test and post-test in one time. On the other hand, students were given advanced post-test to know the durability of retention as many as four times in four months. The results show that there was mean difference between pre-test and post-test based on the Wilcoxon test (z = -3.4, p=0.001). While the effectiveness of treatment is in the high category based on normalized gain values ( = 0.86). Meanwhile, mean difference of all post-test is significantly different based on Analysis of Varian (F = 365.63, p = 0.00). However, in the fourth month, students retention rates began to stabilize based on Tuckey’s HSD (p=0.074) for comparison of mean difference between fourth and fifth post-test. Overall, learning designed can maintain students retention within 4 months after the learning finish.

Emotional intelligence and clinical performance/retention of nursing students

Science.gov (United States)

Marvos, Chelsea; Hale, Frankie B.

2015-01-01

Objective: This exploratory, quantitative, descriptive study was undertaken to explore the relationship between clinical performance and anticipated retention in nursing students. Methods: After approval by the university's Human Subjects Committee, a sample of 104 nursing students were recruited for this study, which involved testing with a valid and reliable emotional intelligence (EI) instrument and a self-report survey of clinical competencies. Results: Statistical analysis revealed that although the group average for total EI score and the 6 score subsets were in the average range, approximately 30% of the individual total EI scores and 30% of two branch scores, identifying emotions correctly and understanding emotions, fell in the less than average range. This data, as well as the analysis of correlation with clinical self-report scores, suggest recommendations applicable to educators of clinical nursing students. Conclusions: Registered nurses make-up the largest segment of the ever-growing healthcare workforce. Yet, retention of new graduates has historically been a challenge for the profession. Given the projected employment growth in nursing, it is important to identify factors which correlate with high levels of performance and job retention among nurses. There is preliminary evidence that EI a nontraditional intelligence measure relates positively not only with retention of clinical staff nurses, but with overall clinical performance as well. PMID:27981096

Predictors of retention in a multicomponent treatment for smokers

Directory of Open Access Journals (Sweden)

Ana Moreno-Coutiño

Full Text Available Abstract Background: There is a lack of knowledge about factors that promote or hinder retention of smokers in treatment. Objective: The aim of this study was the identification of variables that predict retention of smokers who received a multicomponent treatment against smoking. Method: Participants (n = 79 simultaneously received pharmacological and psychological treatment, including an intervention phase prior to the date of smoking cessation. They were evaluated periodically in their abstinence, depressive and anxious symptoms, and were randomly assigned to three treatment conditions (nicotine patch, bupropion or nicotine patch + bupropion. Eighteen variables were grouped into four categories (demographic, consumption pattern, mood and treatment. Data were analyzed using student's t test and X2, for inclusion into a multivariate logistic regression model. Results: Results indicate that age of onset of regular tobacco consumption, secondary education and bupropion pharmacological treatment are significant in relation to the retention of smokers to smoking treatment. Discussion: The reported “age of onset” correlates with treatment retention (OR = 1.545, 95 % CI = 1.175-2.032. This variable has not previously been reported in the literature, and taking it into account in the design of prevention and treatment for smoking could increase their success.

Evaluation of Retention in Methadone Treatment in Patients Attending Baharan Hospital Clinic in Zahedan City

Directory of Open Access Journals (Sweden)

M.D. Mohebi

2015-04-01

Full Text Available Introduction & Objectives: Substance abuse and opioid dependency refers to hazardous use of psychoactive substance .Prevention and treatment of opiate dependence has not been success-ful. Most effective drug in agonist treatment of opiates is methadone maintenance therapy (MMT.But the lack of cooperation of addicts in methadone maintenance therapy has always been a big problem to continue. The purpose of this study is to investigate the retention in the MMT. Materials & Methods: This historical cohort study analyzed the medical records of patients of Baharan hospital in Zahedan. All 912 cases of methadone maintenance clinic of Baharan hos-pital in Zahedan 2011-2012 were studied and the data were analyzed using SPSS. Tables and indexes were analyzed by the Chi-square test and survival curves were plotted using Kaplan–Meier method and analyzed by Log-Rank test. Results: This study reviewed records from 912 patients with a mean age of 34.67% and stan-dard deviation of 10.88 and the range of 15-86 years. 735 were male and 177 ware female. 1-moth retention rate was 71%, 3 months was 59%, 6 months was 47%, 1 year was 30% and 2 years was 17%. Kaplan-Meier median survival time of 8 months was estimated by relation-ship. Doses higher than 60 mg/d of methadone was associated with increased survival on MMT. Conclusion: Age increase, increase of employment time, increasing of the duration of drug abuse, increasing the daily dose of methadone, oral substance abuse increased retention rate and heroin abuse and smoking were associated with decrease retention rate of methadone maintenance therapy. So, with an emphasis on each of these factors effective steps can be taken to improve the cooperation of patients in MMT. (Sci J Hamadan Univ Med Sci 2015; 22 (1:30-36

On the optimal design of risk retention in securitisation

Directory of Open Access Journals (Sweden)

Metin Kaptan

2011-09-01

Full Text Available This paper examines the optimal design of retention in securitisation, in order to maximize welfare of screening per unit of retention, assuming that screening is costly and that the bank intends to securitise its loans. In contrast to the focus of previous literature on tranche retention, we deviate from the constitutional mechanisms of tranche retention to present a pareto-optimal method of tranche retention. Unlike the current ad-hoc-regulations, we derive the optimal design of retention from a utility maximization problem. We show that the level of retention per tranche should be dependent on the rate of credit default, i.e. the higher the rate of default, the higher the optimal rate of retention required to provide an incentive to screen carefully. From this approach, it follows that the rate of retention per tranche should be higher, the higher the position within the ranking order of subordination. Accordingly, the efficiency of tranche retention can be enhanced, reducing the level of retention required to maintain a given level of screening-effort. This retention design entails a recovery of the bank’s equity capital, thereby increasing liquidity and lending capacities.

Average Soil Water Retention Curves Measured by Neutron Radiography

Energy Technology Data Exchange (ETDEWEB)

Cheng, Chu-Lin [ORNL; Perfect, Edmund [University of Tennessee, Knoxville (UTK); Kang, Misun [ORNL; Voisin, Sophie [ORNL; Bilheux, Hassina Z [ORNL; Horita, Juske [Texas Tech University (TTU); Hussey, Dan [NIST Center for Neutron Research (NCRN), Gaithersburg, MD

2011-01-01

Water retention curves are essential for understanding the hydrologic behavior of partially-saturated porous media and modeling flow transport processes within the vadose zone. In this paper we report direct measurements of the main drying and wetting branches of the average water retention function obtained using 2-dimensional neutron radiography. Flint sand columns were saturated with water and then drained under quasi-equilibrium conditions using a hanging water column setup. Digital images (2048 x 2048 pixels) of the transmitted flux of neutrons were acquired at each imposed matric potential (~10-15 matric potential values per experiment) at the NCNR BT-2 neutron imaging beam line. Volumetric water contents were calculated on a pixel by pixel basis using Beer-Lambert s law after taking into account beam hardening and geometric corrections. To remove scattering effects at high water contents the volumetric water contents were normalized (to give relative saturations) by dividing the drying and wetting sequences of images by the images obtained at saturation and satiation, respectively. The resulting pixel values were then averaged and combined with information on the imposed basal matric potentials to give average water retention curves. The average relative saturations obtained by neutron radiography showed an approximate one-to-one relationship with the average values measured volumetrically using the hanging water column setup. There were no significant differences (at p < 0.05) between the parameters of the van Genuchten equation fitted to the average neutron radiography data and those estimated from replicated hanging water column data. Our results indicate that neutron imaging is a very effective tool for quantifying the average water retention curve.

Pharmacological evidence that a failure to recruit NMDA receptors contributes to impaired fear extinction retention in adolescent rats.

Science.gov (United States)

Baker, Kathryn D; Richardson, Rick

2017-09-01

Adolescents, both humans and rodents, exhibit a marked impairment in extinction of fear relative to younger and older groups which could be caused by a failure to efficiently recruit NMDA receptors (NMDARs) in adolescence. It is well-established that systemic administration of NMDAR antagonists (e.g., MK801) before extinction training impairs the retention of extinction in adult and juvenile rodents, but it is unknown whether this is also the case for adolescents. Therefore, in the present study we investigated the effect of pharmacologically manipulating the NMDAR on extinction retention in adolescent rats. When extinction retention is typically impaired (i.e., after one session of extinction training) adolescent male rats given d-cycloserine (a partial NMDAR agonist) showed enhanced extinction retention relative to saline-treated animals while animals given MK801 (a non-competitive antagonist) did not exhibit any further impairment of extinction retention relative to the controls. In a further two experiments we demonstrated that when two sessions of extinction training separated by either 4 or 24h intervals were given to adolescent rats, saline-treated animals exhibited good extinction retention and the animals given MK801 before the second session exhibited impaired extinction retention. These findings suggest that extinction in adolescence does not initially involve NMDARs and this is a likely mechanism that contributes to the impaired fear inhibition observed at this age. However, NMDARs appear to be recruited with extended extinction training or after administration of a partial agonist, both of which lead to effective extinction retention. Copyright © 2016 Elsevier Inc. All rights reserved.

29 CFR 501.46 - Retention of official record.

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Retention of official record. 501.46 Section 501.46 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS ENFORCEMENT OF CONTRACTUAL OBLIGATIONS FOR TEMPORARY ALIEN AGRICULTURAL WORKERS ADMITTED UNDER SECTION 218 OF THE...

29 CFR 502.46 - Retention of official record.

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Retention of official record. 502.46 Section 502.46 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS ENFORCEMENT OF CONTRACTUAL OBLIGATIONS FOR TEMPORARY ALIEN AGRICULTURAL WORKERS ADMITTED UNDER SECTION 218 OF THE...

The application of talent retention theories in Japan and South Korea

OpenAIRE

Le, Tam

2016-01-01

This report is a study of talent management theory – a new approach to HRM to retain and maximize employees’ potentials, relating practices and to what extend it is applied in Japan and South Korea. To better explain why the implementation of talent retention theory may vary from Western countries or the US, a brief look into East (Confucian) Asian culture was taken, as culture plays a decisive role in human behavior and partly determines the archetypical retention requirements of different c...

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.

Influence of particle flux density and temperature on surface modifications of tungsten and deuterium retention

Energy Technology Data Exchange (ETDEWEB)

Buzi, Luxherta, E-mail: l.buzi@fz-juelich.de [Ghent University, Department of Applied Physics, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Edisonbaan 14, 3439 MN, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Institut für Energie und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany); Université de Lorraine, Institut Jean Lamour, CNRS UMR 7198, Bvd. des Aiguillettes, F-54506 Vandoeuvre (France); Temmerman, Greg De [FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Edisonbaan 14, 3439 MN, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Unterberg, Bernhard; Reinhart, Michael; Litnovsky, Andrey; Philipps, Volker [Institut für Energie und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany); Oost, Guido Van [Ghent University, Department of Applied Physics, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); Möller, Sören [Institut für Energie und Klimaforschung – Plasmaphysik, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich (Germany)

2014-12-15

Systematic study of deuterium irradiation effects on tungsten was done under ITER – relevant high particle flux density, scanning a broad surface temperature range. Polycrystalline ITER – like grade tungsten samples were exposed in linear plasma devices to two different ranges of deuterium ion flux densities (high: 3.5–7 · 10{sup 23} D{sup +}/m{sup 2} s and low: 9 · 10{sup 21} D{sup +}/m{sup 2} s). Particle fluence and ion energy, respectively 10{sup 26} D{sup +}/m{sup 2} and ∼38 eV were kept constant in all cases. The experiments were performed at three different surface temperatures 530 K, 630 K and 870 K. Experimental results concerning the deuterium retention and surface modifications of low flux exposure confirmed previous investigations. At temperatures 530 K and 630 K, deuterium retention was higher at lower flux density due to the longer exposure time (steady state plasma operation) and a consequently deeper diffusion range. At 870 K, deuterium retention was found to be higher at high flux density according to the thermal desorption spectroscopy (TDS) measurements. While blisters were completely absent at low flux density, small blisters of about 40–50 nm were formed at high flux density exposure. At the given conditions, a relation between deuterium retention and blister formation has been found which has to be considered in addition to deuterium trapping in defects populated by diffusion.

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...

Fuel retention under elevated wall temperature in KSTAR with a carbon wall

Science.gov (United States)

Cao, B.; Hong, S. H.

2018-03-01

The fuel retention during KSTAR discharges with elevated wall temperature (150 °C) has been studied by using the method of global particle balance. The results show that the elevated wall temperature could reduce the dynamic retention via implantation and absorption, especially for the short pulse shots with large injected fuel particles. There is no signature changing of long-term retention, which related to co-deposition, under elevated wall temperature. For soft-landing shots (normal shots), the exhausted fuel particles during discharges is larger with elevated wall temperature than without, but the exhausted particles after discharges within 90 s looks similar. The outgassing particles because of disruption could be exhausted within 15 s.

Nitrogen assimilation and short term retention in a nutrient-rich tidal freshwater marsh – a whole ecosystem 15N enrichment study

Directory of Open Access Journals (Sweden)

B. Gribsholt

2007-01-01

Full Text Available An intact tidal freshwater marsh system (3477 m2 was labelled by adding 15N-ammonium as a tracer to the flood water inundating the ecosystem. The appearance and retention of 15N-label in different marsh components (leaves, roots, sediment, leaf litter and invertebrate fauna was followed over 15 days. This allowed us to elucidate the direct assimilation and dependence on creek-water nitrogen on a relatively short term and provided an unbiased assessment of the relative importance of the various compartments within the ecosystem. Two separate experiments were conducted, one in spring/early summer (May 2002 when plants were young and building up biomass; the other in late summer (September 2003 when macrophytes were in a flowering or early senescent state. Nitrogen assimilation rate (per hour inundated was >3 times faster in May compared to September. On both occasions, however, the results clearly revealed that the less conspicuous compartments such as leaf litter and ruderal vegetations are more important in nitrogen uptake and retention than the prominent reed (Phragmites australis meadows. Moreover, short-term nitrogen retention in these nutrient rich marshes occurs mainly via microbial pathways associated with the litter and sediment. Rather than direct uptake by macrophytes, it is the large reactive surface area provided by the tidal freshwater marsh vegetation that is most crucial for nitrogen transformation, assimilation and short term retention in nutrient rich tidal freshwater marshes. Our results clearly revealed the dominant role of microbes in initial nitrogen retention in marsh ecosystems.

Best practices in doctoral retention: Mentoring

Directory of Open Access Journals (Sweden)

Judie L. Brill

2014-06-01

Full Text Available  The aim of this critical literature review is to outline best practices in doctoral retention and the successful approach of one university to improve graduation success by providing effective mentorship for faculty and students alike. The focus of this literature review is on distance learning relationships between faculty and doctoral students, regarding retention, persistence, and mentoring models. Key phrases and words used in the search and focusing on mentoring resulted in over 20,000 sources. The search was narrowed to include only doctoral study and mentoring. Research questions of interest were: Why do high attrition rates exist for doctoral students? What are the barriers to retention? What are the benefits of doctoral mentoring? What programs do institutions have in place to reduce attrition? The researchers found a key factor influencing doctoral student retention and success is effective faculty mentorship. In particular, the design of a mentoring and faculty training program to increase retention and provide for success after graduation is important. This research represents a key area of interest in the retention literature, as institutions continue to search for ways to better support students during their doctoral programs and post-graduation. DOI: 10.18870/hlrc.v4i2.186

Female Athletic Training Students' Perceptions of Motherhood and Retention in Athletic Training

Science.gov (United States)

Mazerolle, Stephanie M.; Gavin, Kerri

2013-01-01

Context: Motherhood appears to be a catalyst in job turnover for female athletic trainers, especially those employed at the National Collegiate Athletic Association Division I level. However, most researchers examining this topic have investigated the perspectives of those who are currently employed rather than those who are preparing to enter the profession. Objective: To evaluate female athletic training students' perceptions of motherhood and retention. Design: Qualitative study. Setting: Athletic training education program. Patients or Other Participants: A total of 18 female athletic training students volunteered to participate. They were enrolled in 1 Commission on Accrediting Athletic Training Education–accredited athletic training program and represented 3 levels of academic study. Data Collection and Analysis: The participants responded to a series of questions related to work–life balance and retention in athletic training. Analysis of the data followed a general inductive process. Credibility was established by interpretive member checks and peer review. Results: The first theme, clinical setting, speaks to the belief that work–life balance and retention in athletic training require an employment setting that fosters a family-friendly atmosphere and a work schedule (including travel) that allows for time at home. The second theme, mentorship, reflects the acknowledgment that a female mentor who is successful in balancing the roles of mother and athletic trainer can serve as a role model. The final theme, work–life balance strategies, illustrates the need to have a plan in place to meet the demands of both home and work life. Conclusions: A female athletic trainer who is successfully balancing her career and family responsibilities may be the most helpful factor in retention, especially for female athletic training students. Young professionals need to be educated on the importance of developing successful work–life balance strategies, which can

Female athletic training students' perceptions of motherhood and retention in athletic training.

Science.gov (United States)

Mazerolle, Stephanie M; Gavin, Kerri

2013-01-01

Motherhood appears to be a catalyst in job turnover for female athletic trainers, especially those employed at the National Collegiate Athletic Association Division I level. However, most researchers examining this topic have investigated the perspectives of those who are currently employed rather than those who are preparing to enter the profession. To evaluate female athletic training students' perceptions of motherhood and retention. Qualitative study. Athletic training education program. A total of 18 female athletic training students volunteered to participate. They were enrolled in 1 Commission on Accrediting Athletic Training Education-accredited athletic training program and represented 3 levels of academic STUDY. The participants responded to a series of questions related to work-life balance and retention in athletic training. Analysis of the data followed a general inductive process. Credibility was established by interpretive member checks and peer review. The first theme, clinical setting, speaks to the belief that work-life balance and retention in athletic training require an employment setting that fosters a family-friendly atmosphere and a work schedule (including travel) that allows for time at home. The second theme, mentorship, reflects the acknowledgment that a female mentor who is successful in balancing the roles of mother and athletic trainer can serve as a role model. The final theme, work-life balance strategies, illustrates the need to have a plan in place to meet the demands of both home and work life. A female athletic trainer who is successfully balancing her career and family responsibilities may be the most helpful factor in retention, especially for female athletic training students. Young professionals need to be educated on the importance of developing successful work-life balance strategies, which can be helpful in reducing attrition from the profession.

Prolonged postpartum urinary retention: A case report and review of ...

African Journals Online (AJOL)

Postpartum urinary retention (PUR), which is defined as difficulty in emptying the bladder completely after ... Although many risk factors for this disturbance are identified in ... Despite incontinence related to pregnancy or labour having been.

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...

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.

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)

Effects of temperature and body size on radiocaesium retention in brown trout, Salmo trutta

International Nuclear Information System (INIS)

Ugedal, O.; Jonsson, B.; Njastad, O.; Naeumann, R.

1992-01-01

The elimination rate of radiocaesium in brown trout Salmo trutta L. was determined in the laboratory at four water temperatures (range 4.4 -15.6 0 C). In the experiments three or four homogeneous size-groups of fish (mean weights 23-496g) were studied at each temperature. The brown trout received acute oral doses of 134 Cs and were killed at intervals for radioactivity counting. The retention versus time curves were composed of two distinct exponential components. The long-lived component was quantitatively the most important for retention of radiocaesium. Elimination rate increased with increasing water temperature and decreased with increasing body weight. The biological half-life of 134 Cs (T b , days) was related to fresh body weight (W, g) and water temperature (t, 0 C) by the equation: T b = 290 x W 0.176 x e -0.106 x t . The elimination rate of Cs could be predicted from weight-specific metabolic rate as given by Elliott's equations for brown trout. (author)

New York's Health Care Workforce Recruitment and Retention Act: an investigation of the effects of nonrecurring increases in health worker wage on health worker supply.

Science.gov (United States)

Patel, Kavin

2014-01-01

This article analyzes New York's Health Care Workforce Recruitment and Retention Act of 2002. The analysis comes in 4 parts: part 1 provides a brief overview of New York's economy as it relates to health care, a feel for the political climate at the time, and a detailed presentation of the chain of events that connect this climate to the birth of the Health Care Workforce Recruitment and Retention Act of 2002; part 2 consists of a breakdown of the provisions contained within bill, including major and minor goals, intended effects, and the mechanics behind raising supporting funds; part 3 explores what actually happened by evaluating available data to determine whether the bill's 2 major goals of workforce recruitment and retention were fulfilled; and finally, part 4 will take all the aforementioned information to determine the overall success of the bill, the implications, and specific suggestions for future policy changes that time has revealed since its inception.

Estimation for Retention Factor of Isoflavones in Physico-Chemical Properties

International Nuclear Information System (INIS)

Lee, Seung Ki; Row, Kyung Ho

2003-01-01

The estimation of retention factors by correlation equations with physico-chmical properties maybe helpful in chromatographic work. The physico-chemical properties were water solubility (S), hydrophobicity (P), total energy (Et), connectivity index 1 (1χ), hydrophilic-lipophlic balance (x) and hydrophilic surface area (h) of isoflavones. The retention factors were experimentally measured by RP-HPLC. Especially, the empirical regulations of water solubility and hydrophobicity were expressed in a linear form. The equation between retention factors and various physico-chemical properties of isoflavones was suggested as k = a0 + a 1 log S + a2 log P Q + a3 (E t ) + a4 ( 1 χ) + a5 (x) + a6 (h), and the correlation coefficients estimated were relatively higher than 0.95. The empirical equations might be successfully used for a prediction of the various chromatographic characteristics of substances, with a similar chemical structure

Development of Calculation Module for Intake Retention Functions based on Occupational Intakes of Radionuclides

Energy Technology Data Exchange (ETDEWEB)

Noh, Siwan; Kwon, Tae-Eun; Lee, Jai-Ki [Hanyang Univ., Seoul (Korea, Republic of); Lee, Jong-Il; Kim, Jang-Lyul [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-10-15

In internal dosimetry, intake retention and excretion functions are essential to estimate intake activity using bioassay sample such as whole body counter, lung counter, and urine sample. Even though ICRP (International Commission on Radiological Protection)provides the functions in some ICRP publications, it is needed to calculate the functions because the functions from the publications are provided for very limited time. Thus, some computer program are generally used to calculate intake retention and excretion functions and estimate intake activity. OIR (Occupational Intakes of Radionuclides) will be published soon by ICRP, which totally replaces existing internal dosimetry models and relevant data including intake retention and excretion functions. Thus, the calculation tool for the functions is needed based on OIR. In this study, we developed calculation module for intake retention and excretion functions based on OIR using C++ programming language with Intel Math Kernel Library. In this study, we developed the intake retention and excretion function calculation module based on OIR using C++ programing language.

Development of Calculation Module for Intake Retention Functions based on Occupational Intakes of Radionuclides

International Nuclear Information System (INIS)

Noh, Siwan; Kwon, Tae-Eun; Lee, Jai-Ki; Lee, Jong-Il; Kim, Jang-Lyul

2014-01-01

In internal dosimetry, intake retention and excretion functions are essential to estimate intake activity using bioassay sample such as whole body counter, lung counter, and urine sample. Even though ICRP (International Commission on Radiological Protection)provides the functions in some ICRP publications, it is needed to calculate the functions because the functions from the publications are provided for very limited time. Thus, some computer program are generally used to calculate intake retention and excretion functions and estimate intake activity. OIR (Occupational Intakes of Radionuclides) will be published soon by ICRP, which totally replaces existing internal dosimetry models and relevant data including intake retention and excretion functions. Thus, the calculation tool for the functions is needed based on OIR. In this study, we developed calculation module for intake retention and excretion functions based on OIR using C++ programming language with Intel Math Kernel Library. In this study, we developed the intake retention and excretion function calculation module based on OIR using C++ programing language

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.

Stability of Balloon-Retention Gastrostomy Tubes with Different Concentrations of Contrast Material: In Vitro Study

International Nuclear Information System (INIS)

Lopera, Jorge E.; Alvarez, Alex; Trimmer, Clayton; Josephs, Shellie; Anderson, Matthew; Dolmatch, Bart

2009-01-01

The purpose of this study was to determine the performance of two balloon-retention-type gastrostomy tubes when the balloons are inflated with two types of contrast materials at different concentrations. Two commonly used balloon-retention-type tubes (MIC and Tri-Funnel) were inflated to the manufacturer's recommended volumes (4 and 20 cm 3 , respectively) with normal saline or normal saline plus different concentrations of contrast material. Five tubes of each brand were inflated with normal saline and 0%, 25%, 50%, 75%, and 100% contrast material dilutions, using either nonionic hyperosmolar contrast, or nonionic iso-osmolar contrast. The tubes were submerged in a glass basin containing a solution with a pH of 4. Every week the tubes were visually inspected to determine the integrity of the balloons, and the diameter of the balloons was measured with a caliper. The tests were repeated every week for a total of 12 weeks. The MIC balloons deflated slightly faster over time than the Tri-Funnel balloons. The Tri-Funnel balloons remained relatively stable over the study period for the different concentrations of contrast materials. The deflation rates of the MIC balloons were proportionally related to the concentration of saline and inversely related to the concentration of the contrast material. At high contrast material concentrations, solidification of the balloons was observed. In conclusion, this in vitro study confirms that the use of diluted amounts of nonionic contrast materials is safe for inflating the balloons of two types of balloon-retention feeding tubes. High concentrations of contrast could result in solidification of the balloons and should be avoided.

Attainment and retention of force moderation following laparoscopic resection training with visual force feedback.

Science.gov (United States)

Hernandez, Rafael; Onar-Thomas, Arzu; Travascio, Francesco; Asfour, Shihab

2017-11-01

Laparoscopic training with visual force feedback can lead to immediate improvements in force moderation. However, the long-term retention of this kind of learning and its potential decay are yet unclear. A laparoscopic resection task and force sensing apparatus were designed to assess the benefits of visual force feedback training. Twenty-two male university students with no previous experience in laparoscopy underwent relevant FLS proficiency training. Participants were randomly assigned to either a control or treatment group. Both groups trained on the task for 2 weeks as follows: initial baseline, sixteen training trials, and post-test immediately after. The treatment group had visual force feedback during training, whereas the control group did not. Participants then performed four weekly test trials to assess long-term retention of training. Outcomes recorded were maximum pulling and pushing forces, completion time, and rated task difficulty. Extreme maximum pulling force values were tapered throughout both the training and retention periods. Average maximum pushing forces were significantly lowered towards the end of training and during retention period. No significant decay of applied force learning was found during the 4-week retention period. Completion time and rated task difficulty were higher during training, but results indicate that the difference eventually fades during the retention period. Significant differences in aptitude across participants were found. Visual force feedback training improves on certain aspects of force moderation in a laparoscopic resection task. Results suggest that with enough training there is no significant decay of learning within the first month of the retention period. It is essential to account for differences in aptitude between individuals in this type of longitudinal research. This study shows how an inexpensive force measuring system can be used with an FLS Trainer System after some retrofitting. Surgical

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.

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).

29 CFR 801.74 - Retention of official record.

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Retention of official record. 801.74 Section 801.74 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR OTHER LAWS APPLICATION... part shall be maintained and filed under the custody and control of the Chief Administrative Law Judge. ...

Student Mental Models of the Greenhouse Effect: Retention Months After Interventions

Science.gov (United States)

Harris, S. E.; Gold, A. U.

2013-12-01

Individual understanding of climate science, and the greenhouse effect in particular, is one factor important for societal decision-making. Ideally, learning opportunities about the greenhouse effect will not only move people toward expert-like ideas but will also have long-lasting effects for those individuals. We assessed university students' mental models of the greenhouse effect before and after specific learning experiences, on a final exam, then again a few months later. Our aim was to measure retention after students had not necessarily been thinking about, nor studying, the greenhouse effect recently. How sticky were the ideas learned? 164 students in an introductory science course participated in a sequence of two learning activities and assessments regarding the greenhouse effect. The first lesson involved the full class, then, for the second lesson, half the students completed a simulation-based activity and the other half completed a data-driven activity. We assessed student thinking through concept sketches, multiple choice and short answer questions. All students generated concept sketches four times, and completed a set of multiple choice (MCQs) and short answer questions twice. Later, 3-4 months after the course ended, 27 students ('retention students') completed an additional concept sketch and answered the questions again, as a retention assessment. These 27 students were nearly evenly split between the two contrasting second lessons in the sequence and included both high and low-achieving students. We then compared student sketches and scores to 'expert' answers. The general pattern over time showed a significant increase in student scores from before the lesson sequence to after, both on concept sketches and MCQs, then an additional increase in concept sketch score on the final exam (MCQs were not asked on the final exam). The scores for the retention students were not significantly different from the full class. Within the retention group

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.

Gastrointestinal absorption and retention of plutonium and uranium in the baboon

International Nuclear Information System (INIS)

Larsen, R.P.; Bhattacharyya, M.H.; Oldham, R.D.; Moretti, E.S.; Cohen, N.

1984-01-01

Individual isotopes of plutonium and uranium were administered both intragastrically and intravenously to a baboon. Samples of urine, faces, blood, and tissues were taken and are now being analyzed. Preliminary results indicate that the fractional absorptions of plutonium and uranium were 1 x 10 -3 and 1 x 10 -2 , respectively, and their retentions about one month later were about 20% and 10%, respectively, of the amounts absorbed. The fractional retentions of the intravenously injected plutonium and uranium at that time were 0.90 and 0.07. 13 references, 1 figure, 3 tables

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%.

Factors affecting the retention of methyl iodide by iodide-impregnated carbon

International Nuclear Information System (INIS)

Hyder, M.L.; Malstrom, R.A.

1991-01-01

This paper comprises two sets of studies of methyl iodide retention by iodide-impregnated carbon. In the first of these, the retention of the methyl iodide on the carbon surface and its subsequent evolution were observed directly by a technique of combustion and phosphorescence. In the second, the methyl iodide retention in a standard test was compared with surface area measurements and the concentration of unreacted iodine. A correlation among these parameters was identified and characterized. Carbon quality was varied through the selection of used material with differing service histories. Air from the Savannah River Site reactor buildings is vented through carbon beds for control of radioiodine before release to the atmosphere. The carbon used is North American Carbon Co. type GX-176 coconut shell carbon impregnated with 1% triethylenedimaine (TEDA) and 2% potassium iodide by weight. Replacement intervals for the carbon have been as long as thirty months. Analysis of samples withdrawn at much shorter times has shown that the TEDA is lost after a few months, and the performance of the carbon for methyl iodide retention is dependent on the iodide impregnant. Efficient methyl iodide retention is not a requirement for carbon in this service; however, methyl iodide retention as measured by the ASTM Test D3803 (method B) has been found to correlate well with other desirable properties of the carbon such as radiation stability. The studies undertaken here were intended to shed light on the changes taking place in this carbon during long-term service and to provide a basis for simpler measurements of carbon quality

Interception and retention of technetium by vegetation and soil

International Nuclear Information System (INIS)

Hoffman, F.O.; Garten, C.T. Jr.; Huckabee, J.W.; Lucas, D.M.

1982-01-01

Field experiments were performed to quantify the initial interception and retention of technetium (Tc) by herbaceous vegetation as a consequence of direct deposition and uptake from soil. A simulated rain containing a solution of 95 /sup m/TcO 4 - was applied to plots of bare soil and plots with standing vegetation. Vegetation emerging in the baresoil plots obtained Tc predominantly from root uptake. Vegetation standing during the initial application obtained Tc from both direct foliar interception and root uptake. For the plots with standing vegetation, the estimated initial interception fraction (r) ranged from 0.079 to 0.17. The mass interception factor (r/Y/sub v/) ranged from 0.65 to 1.1 m 2 /kg. The retention of Tc by vegetation receiving direct foliar contamination varied with environmental half-times (T/sub w/) ranging from 15.9 to 18.7 days. Adjusting for the effects of growth dilution increased the values of T/sub w/ (range 21.6-28.7 days). For vegetation emerging from the plots of initial bare soil, retention was equivalent to a T/sub w/ of 43 days. These data indicated that uptake of Tc from soil diminished with time and that Tc was removed from plant tissue. In soil, a downward movement was evident, because Tc in the top 2 cm decreased with time and concentrations at lower soil depths (6-8 and 14-15 cm) and increased with time. The application of these data to predict steady-state concentrations of Tc in vegetation resulting from continuous deposition does not differ substantially from predictions based on the use of generic-default parameter values recommend in Regulatory Guide 1.109 of the U. S. Nuclear Regulatory Commission

Emotional intelligence and clinical performance/retention of nursing students

Directory of Open Access Journals (Sweden)

Chelsea Marvos

2015-01-01

Full Text Available Objective: This exploratory, quantitative, descriptive study was undertaken to explore the relationship between clinical performance and anticipated retention in nursing students. Methods: After approval by the university′s Human Subjects Committee, a sample of 104 nursing students were recruited for this study, which involved testing with a valid and reliable emotional intelligence (EI instrument and a self-report survey of clinical competencies. Results: Statistical analysis revealed that although the group average for total EI score and the 6 score subsets were in the average range, approximately 30% of the individual total EI scores and 30% of two branch scores, identifying emotions correctly and understanding emotions, fell in the less than average range. This data, as well as the analysis of correlation with clinical self-report scores, suggest recommendations applicable to educators of clinical nursing students. Conclusions: Registered nurses make-up the largest segment of the ever-growing healthcare workforce. Yet, retention of new graduates has historically been a challenge for the profession. Given the projected employment growth in nursing, it is important to identify factors which correlate with high levels of performance and job retention among nurses. There is preliminary evidence that EI "a nontraditional intelligence measure" relates positively not only with retention of clinical staff nurses, but with overall clinical performance as well.

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.

Building the Relations of New and Veteran Teachers to Address Retention: An Action Research Study

Science.gov (United States)

Roberts, John-Bernard

2016-01-01

This dissertation analyzed the factors that affected the retention of new teachers in the United States. This action research study was conducted utilizing qualitative data. Qualitative methods were relied upon to investigate perspectives from new and veteran teachers. It was proposed that teachers left the profession due to opportunity cost…

Evaluation of Data Retention Characteristics for Ferroelectric Random Access Memories (FRAMs)

Science.gov (United States)

Sharma, Ashok K.; Teverovsky, Alexander

2001-01-01

Data retention and fatigue characteristics of 64 Kb lead zirconate titanate (PZT)-based Ferroelectric Random Access Memories (FRAMs) microcircuits manufactured by Ramtron were examined over temperature range from -85 C to +310 C for ceramic packaged parts and from -85 C to +175 C for plastic parts, during retention periods up to several thousand hours. Intrinsic failures, which were caused by a thermal degradation of the ferroelectric cells, occurred in ceramic parts after tens or hundreds hours of aging at temperatures above 200 C. The activation energy of the retention test failures was 1.05 eV and the extrapolated mean-time-to-failure (MTTF) at room temperature was estimated to be more than 280 years. Multiple write-read cycling (up to 3x10(exp 7)) during the fatigue testing of plastic and ceramic parts did not result in any parametric or functional failures. However, operational currents linearly decreased with the logarithm of number of cycles thus indicating fatigue process in PZT films. Plastic parts, that had more recent date code as compared to ceramic parts, appeared to be using die with improved process technology and showed significantly smaller changes in operational currents and data access times.

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.

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.

Comparison of iodine, krypton, and xenon retention efficiencies for various silver loaded adsorption media

International Nuclear Information System (INIS)

Huchton, R.L.; Tkachyk, J.W.; Taylor, J.T.; Motes, B.G.

1985-03-01

A comparison was made among various silver impregnated adsorption media to determine their iodine, krypton, and xenon retention efficiencies. The program consisted of three components. First, laboratory measurements of the noble gas retention efficiencies of commercially available adsorption media were determined as a function of relative humidity, sample duration, test cartridge geometry, and ambient air purge. Second, a literature survey was performed to evaluate the iodine species retention efficiencies of the selected media. Third, data associated with a media previously proposed for an emergency response air sampler were incorporated to enlarge the data base. 41 refs., 6 figs., 14 tabs

The Effect of Internal Salary Increment Distributions on Retention Behaviors of Western New York Teachers

Science.gov (United States)

Patterson, Michele M.

2013-01-01

This is a study of district internal salary distribution practices and its effect on retention. The study is a replication study as recommended by Jacobson (1986) and Lankford and Wyckoff (1997) whereby their research shows the prevalence of "back loading" and ineffectiveness relative to retention. In the case of this study, the…

Addressing the crisis of GP recruitment and retention: a systematic review.

Science.gov (United States)

Marchand, Catherine; Peckham, Stephen

2017-04-01

The numbers of GPs and training places in general practice are declining, and retaining GPs in their practices is an increasing problem. To identify evidence on different approaches to retention and recruitment of GPs, such as intrinsic versus extrinsic motivational determinants. Synthesis of qualitative and quantitative research using seven electronic databases from 1990 onwards (Medline, Embase, Cochrane Library, Health Management Information Consortium [HMIC], Cumulative Index to Nursing and Allied Health Literature (Cinahl), PsycINFO, and the Turning Research Into Practice [TRIP] database). A qualitative approach to reviewing the literature on recruitment and retention of GPs was used. The studies included were English-language studies from Organisation for Economic Cooperation and Development countries. The titles and abstracts of 138 articles were reviewed and analysed by the research team. Some of the most important determinants to increase recruitment in primary care were early exposure to primary care practice, the fit between skills and attributes, and a significant experience in a primary care setting. Factors that seemed to influence retention were subspecialisation and portfolio careers, and job satisfaction. The most important determinants of recruitment and retention were intrinsic and idiosyncratic factors, such as recognition, rather than extrinsic factors, such as income. Although the published evidence relating to GP recruitment and retention is limited, and most focused on attracting GPs to rural areas, the authors found that there are clear overlaps between strategies to increase recruitment and retention. Indeed, the most influential factors are idiosyncratic and intrinsic to the individuals. © British Journal of General Practice 2017.

Structure-retention and mobile phase-retention relationships for reversed-phase high-performance liquid chromatography of several hydroxythioxanthone derivatives in binary acetonitrile-water mixtures

International Nuclear Information System (INIS)

Amiri, Ali Asghar; Hemmateenejad, Bahram; Safavi, Afsaneh; Sharghi, Hashem; Beni, Ali Reza Salimi; Shamsipur, Mojtaba

2007-01-01

The reversed-phase high-performance liquid chromatographic (RP-HPLC) behavior of some newly synthesized hydroxythioxanthone derivatives using binary acetonitrile-water mixtures as mobile phase has been examined. First, the variation in the retention time of each molecule as a function of mobile phase properties was studied by Kamlet-Taft solvatochromic equations. Then, the influences of molecular structure of the hydroxythioxanthone derivatives on their retention time in various mobile phase mixtures were investigated by quantitative structure-property relationship (QSPR) analysis. Finally, a unified model containing both the molecular structure parameters and mobile phase properties was developed to describe the chromatographic behavior of the systems studied. Among the solvent properties, polarity/polarizability parameter (π * ) and hydrogen-bond basicity (β), and among the solute properties, the most positive local charge (MPC), the sum of positive charges on hydrogen atoms contributing in hydrogen bonding (SPCH) and lipophilicity index (log P) were identified as controlling factors in the RP-HPLC behavior of hydroxythioxanthone derivatives in actonitrile-water binary solvents

Predicting the Campbell Soil Water Retention Function: Comparing Visible–Near-Infrared Spectroscopy with Classical Pedotransfer Function

DEFF Research Database (Denmark)

Chrysodonta, Zampela Pittaki; Møldrup, Per; Knadel, Maria

2018-01-01

The soil water retention curve (SWRC) is essential for the modeling of water flow and chemical transport in the vadose zone. The Campbell function and its b (pore-size distribution index) parameter fitted to measured data is a simple method to quantify retention under relatively moist conditions...

Effect of dose on lead retention and distribution in suckling and adult female mice

International Nuclear Information System (INIS)

Keller, C.A.; Doherty, R.A.

1980-01-01

Single doses of lead (trace to 445 mg/kg) were administered per os to suckling and adult mice. Both groups exhibited dose-independent lead retention when doses of 4 to 445 mg/kg were administered. However, developmental differences in the fraction of initial dose (FID) retained were evident for all doses administered. A much larger FID was retained in both age groups following administration of carrier-free 203 Pb. The results are consistent with a mechanism of gastrointestinal lead absorption comprising two or more processes. Developmental differences were also observed in organ lead concentration relative to whole body concentration for kidneys, skull and brain 6 days following lead administration. Lead retentions (relative to whole body retention) in brain and in bone were linearly related to dose of lead administered in both suckling and adult age groups. Though uptake of lead into brain and into femur was observed to be directly related to dose over a wide range, relative blood lead concentrations were not linearly correlated with dose administered. The relationships between lead concentrations of blood and organ(s) were also shown to be nonlinear relative to dose. However, blood lead concentration was found to be a reliable indicator of kidney and liver lead concentrations following an acute lead exposure

The drivers of student enrolment and retention: A stakeholder ...

African Journals Online (AJOL)

The main factors that undermined enrolment and retention were the scope of research and tuition, institutional performance, inconsistency in teaching quality and the relative inaccessibility of tuition material. The research framework described in this paper offers a promising resource for the student development strategies of ...

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).

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.

Managing student retention through the assessment of cost of quality

African Journals Online (AJOL)

The primary goal of this article is to introduce a relatively new costing tool that could assist with the formulation of a retention strategy. There is a cost factor linked to the education and training of students: the money spent on a successful student could be perceived as adding value; whilst the costs related to unsuccessful ...

Empowering employees with chronic diseases: process evaluation of an intervention aimed at job retention.

Science.gov (United States)

Varekamp, Inge; Krol, Boudien; van Dijk, Frank J H

2011-01-01

Employees with a chronic disease may experience work-related problems that contribute to the risk of job loss. We developed a group-based intervention programme aimed at clarifying problems, making these a subject of discussion at work, and realizing solutions. This process evaluation investigates the intervention's feasibility and the satisfaction of 64 participants in eight groups. Data were collected through process evaluation forms and self-report questionnaires. The recruitment of participants was time-consuming. Highly educated women working in the service sector were overrepresented. The programme was administered as planned, although components were sometimes only discussed briefly, due to lack of time. Satisfaction with the overall programme among participants was high; it was perceived as effective and there were only three dropouts. In particular, the focus on feelings and thoughts about having a chronic disease was highly valued, as were the exchange of experiences and role-playing directed at more assertive communication. A vocational rehabilitation programme aimed at job retention is feasible and is perceived to be effective. Such a programme should address psychosocial aspects of working with a chronic disease beside practical problems. The recruitment of participants is time-consuming. Cooperation with outpatient clinics is necessary in order to reach all groups of employees with a chronic disease that might benefit from job retention programmes. ISRCTN77240155.

Pengaruh Customer Satisfaction terhadap Customer Retention (Survei Pelanggan J.co Donut & Coffee Malang)

OpenAIRE

Tanjung, Andhika; Sanawiri, Brillyanes

2017-01-01

This research aims to identify influence of Customer Satisfaction, to Customer Retention. The independent varible in this research are Customer Satsisfaction (X), with the dependent variable Customer Retention (Y). The type of research is explanatory research with quantitative approach. The object of research is the customer J.Co Donut & Coffee with minimum purchase at least 2 times. The sampling after selectes by purposive sampling tehcnique is as many as 116 people of respondents. The d...

Artificial neural network prediction of quantitative structure - retention relationships of polycyclic aromatic hydocarbons in gas chromatography

Directory of Open Access Journals (Sweden)

SNEZANA SREMAC

2005-11-01

Full Text Available A feed-forward artificial neural network (ANN model was used to link molecular structures (boiling points, connectivity indices and molecular weights and retention indices of polycyclic aromatic hydrocarbons (PAHs in linear temperature-programmed gas chromatography. A randomly taken subset of PAH retention data reported by Lee et al. [Anal. Chem. 51 (1979 768], containing retention index data for 30 PAHs, was used to make the ANN model. The prediction ability of the trained ANN was tested on unseen data for 18 PAHs from the same article, as well as on the retention data for 7 PAHs experimentally obtained in this work. In addition, two different data sets with known retention indices taken from the literature were analyzed by the same ANN model. It has been shown that the relative accuracy as the degree of agreement between the measured and the predicted retention indices in all testing sets, for most of the studied PAHs, were within the experimental error margins (±3%.

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

Xenon-133 hepatic retention ratio: A useful index for fatty liver quantification

International Nuclear Information System (INIS)

Yeh, S.H.; Wu, L.C.; Wang, S.J.; Lin, H.C.; Liu, R.S.; Lee, S.D.; Wu, J.C.

1989-01-01

Xenon-133 hepatic retention ratio was developed for quantifying fatty liver. Data were acquired in frame mode in the hepatic region and both lung bases for 5 min after rebreathing 20 mCi of gaseous 133 Xe and for another 5 min during washout. Static [ 99m Tc]sulfur colloid liver imaging was performed with the patient in the identical position immediately after the ventilation study and data were stored for liver localization. A hepatic time-activity curve corrected for background activity was generated. The 133Xe retention ratio was derived by dividing the activity at 3.5 min after washout by the peak activity. The data of 16 controls and 20 patients with fatty liver were analyzed. The retention ratio (mean +/- s.d.) was greatly increased in patients with fatty infiltration (0.43 +/- 0.20 vs. 0.04 +/- 0.08 in controls, p less than 0.001). There was a strong positive correlation between the 133 Xe retention ratios and percentage of fat on biopsy as assessed by the amount of the liver tissue occupied by fat globules on H ampersand E stained sections. The 133 Xe hepatic retention ratio is a simple, accurate and clinically useful index of detecting, quantifying and managing fatty infiltration of the liver

Employee retention: a customer service approach.

Science.gov (United States)

Gerson, Richard F

2002-01-01

Employee retention is a huge problem. There are staff shortages in radiology because not enough people are entering the profession; too many people are leaving the profession for retirement, higher-paying jobs or jobs with less stress; and there are not enough opportunities for career advancement. Staff shortages are exacerbated by difficulty in retaining people who enter the profession. While much work has been focused on recruitment and getting more people "in the front door," I suggest that the bulk of future efforts be focused on employee retention and "closing the back door." Employee retention must be an ongoing process, not a program. Approaches to employee retention that focus on external things, i.e., things that the company can do to or for the employee, generally are not successful. The truth is that employee retention processes must focus on what the employee gets out of the job. The process must be a benefits-based approach that helps employees answer the question, "What's in it for me?" The retention processes must be ongoing and integrated into the daily culture of the company. The best way to keep your employees is to treat them like customers. Customer service works for external customers. We treat them nicely. We work to satisfy them. We help them achieve their goals. Why not do the same for our employees? If positive customer service policies and practices can satisfy and keep external customers, why not adapt these policies and practices for employees? And, there is a service/satisfaction link between employee retention and higher levels of customer satisfaction. Customers prefer dealing with the same employees over and over again. Employee turnover destroys a customer's confidence in the company. Just like a customer does not want to have to "train and educate" a new provider, they do not want to do the same for your "revolving door" employees. So, the key is to keep employees so they in turn will help you keep your customers. Because the

Deuterium retention in molten salt electrodeposition tungsten coatings

International Nuclear Information System (INIS)

Zhou, Hai-Shan; Xu, Yu-Ping; Sun, Ning-Bo; Zhang, Ying-Chun; Oya, Yasuhisa; Zhao, Ming-Zhong; Mao, Hong-Min; Ding, Fang; Liu, Feng; Luo, Guang-Nan

2016-01-01

Highlights: • We investigate D retention in electrodeposition W coatings. • W coatings are exposed to D plasmas in the EAST tokamak. • A cathodic current density dependence on D retention is found. • Electrodeposition W exhibits lower D retention than VPS-W. - Abstract: Molten salt electrodeposition is a promising technology to manufacture the first wall of a fusion reactor. Deuterium (D) retention behavior in molten salt electrodeposition tungsten (W) coatings has been investigated by D-plasma exposure in the EAST tokamak and D-ion implantation in an ion beam facility. Tokamak exposure experiments demonstrate that coatings prepared with lower current density exhibit less D retention and milder surface damage. Deuterium-ion implantation experiments indicate the D retention in the molten salt electrodeposition W is less than that in vacuum plasma spraying W and polycrystalline W.

Deuterium retention in molten salt electrodeposition tungsten coatings

Energy Technology Data Exchange (ETDEWEB)

Zhou, Hai-Shan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Xu, Yu-Ping [Science Island Branch of Graduate School, University of Science and Technology of China, Hefei (China); Sun, Ning-Bo; Zhang, Ying-Chun [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing (China); Oya, Yasuhisa [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan); Zhao, Ming-Zhong [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Mao, Hong-Min [Science Island Branch of Graduate School, University of Science and Technology of China, Hefei (China); Ding, Fang; Liu, Feng [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Luo, Guang-Nan, E-mail: gnluo@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Science Island Branch of Graduate School, University of Science and Technology of China, Hefei (China); Hefei Center for Physical Science and Technology, Hefei (China); Hefei Science Center of Chinese Academy of Science, Hefei (China)

2016-12-15

Highlights: • We investigate D retention in electrodeposition W coatings. • W coatings are exposed to D plasmas in the EAST tokamak. • A cathodic current density dependence on D retention is found. • Electrodeposition W exhibits lower D retention than VPS-W. - Abstract: Molten salt electrodeposition is a promising technology to manufacture the first wall of a fusion reactor. Deuterium (D) retention behavior in molten salt electrodeposition tungsten (W) coatings has been investigated by D-plasma exposure in the EAST tokamak and D-ion implantation in an ion beam facility. Tokamak exposure experiments demonstrate that coatings prepared with lower current density exhibit less D retention and milder surface damage. Deuterium-ion implantation experiments indicate the D retention in the molten salt electrodeposition W is less than that in vacuum plasma spraying W and polycrystalline W.

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.

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.

Study of water retention capacity in mortars with the incorporation of exhaust powder

International Nuclear Information System (INIS)

Pereira, Helena Ravache Samy; Valentina, Luiz Veriano Oliveira Dalla; Priscila Warch

2011-01-01

The purpose of this study is to suggest the incorporation of exhaust powder waste in mortars for laying and coating walls and ceilings, to evaluate the representative proportions through mixture design, aiming for a satisfactory performance of the analyzed property and the water retention capacity. In the experimental procedure ten mixtures were performed with consistence index of 230±10mm. The surface response generated showed a water retention capacity in mortar varying from 88% to 95%, which could be classified as normal and high. In relation to the water retention, the incorporation of foundry exhaust powder waste in the studied proportions is viable in mortars for laying and coating walls and ceilings. (author)

Factors Affecting Retention Behavior: A Model To Predict At-Risk Students. AIR 1997 Annual Forum Paper.

Science.gov (United States)

Sadler, William E.; Cohen, Frederic L.; Kockesen, Levent

This paper describes a methodology used in an on-going retention study at New York University (NYU) to identify a series of easily measured factors affecting student departure decisions. Three logistic regression models for predicting student retention were developed, each containing data available at three distinct times during the first…

Identifying research priorities for effective retention strategies in clinical trials.

Science.gov (United States)

Kearney, Anna; Daykin, Anne; Shaw, Alison R G; Lane, Athene J; Blazeby, Jane M; Clarke, Mike; Williamson, Paula; Gamble, Carrol

2017-08-31

during a trial, the use of routinely collected data, the frequency and timing of reminders, triggered site training and the time needed to complete questionnaires was deemed critical. Research into the effectiveness of Christmas cards for site staff was not of critical importance. The surveys of current practices demonstrates that a variety of strategies are being used to mitigate missing data but with little evidence to support their use. Six retention strategies were deemed critically important within the Delphi survey and should be a primary focus of future retention research.

75 FR 32984 - Policy on the Retention of Supporting Documents and the Use of Electronic Mobile Communication...

Science.gov (United States)

2010-06-10

...-0168] Policy on the Retention of Supporting Documents and the Use of Electronic Mobile Communication... changes regarding the retention of supporting documents and the use of electronic mobile communication... electronic mobile communication/tracking records to be supporting documents, as they record the time, date...

A Cost Benefit Analysis Between the Current Naval Officer Retention Bonus Plan and the Enlisted Retention Bonus Plan

Science.gov (United States)

2016-06-01

that personnel targeted for retention had a direct ability to affect the success of the transaction and company. High potential, job function, job level...and job title rounded out the top five reasons personnel were targeted for retention . In brief, this study found that slightly more than half of...lower income may value the job security provided by service in the military, thus making retention in the military a more attractive option. 4

Effect of lowering dietary calcium intake on fractional whole body calcium retention

International Nuclear Information System (INIS)

Dawson-Hughes, B.; Stern, D.T.; Shipp, C.C.; Rasmussen, H.M.

1988-01-01

Although fractional calcium absorption is known to vary inversely with calcium intake, the extent and timing of individual hormonal and calcium absorption responses to altered calcium intake have not been defined. We measured fractional whole body retention of orally ingested 47 Ca, an index of calcium absorption, in nine normal women after they had eaten a 2000-mg calcium diet for 8 weeks and a 300-mg calcium diet for 1, 2, 4, and 8 weeks. After the diet change, serum intact PTH (32.2% increase; P = 0.005), serum 1,25-dihydroxyvitamin D [1,25-(OH)2D; 43.8% increase; P = 0.003], and fractional whole body calcium retention (42.8% increase; P = 0.004) increased within 1 week. Although the PTH and calcium retention responses remained fairly constant throughout the low calcium intake period, serum 1,25-(OH)2D concentrations declined toward baseline after week 1. Thus, the late increase in calcium retention may have resulted from calcium absorption that was independent of 1,25-(OH)2D stimulation

Positive organisation:  the role of leader behaviour in work engagement and retention

OpenAIRE

Mendes, Fallen; Stander, Marius W.

2011-01-01

Orientation: The positive organisation creates a framework in which its elements can be investigated in relation to the retention of talent. Research purpose: The aim of this study was to investigate if leader empowering behaviour can positively impact on role clarity, psychological empowerment and work engagement, with the final outcome being the retention of talent. Motivation for the study: In the ever changing work environment organisations place great emphasis on their human ...

Injuries from Non-Retention in Gillnet Fisheries Suppress Reproductive Maturation in Escaped Fish

OpenAIRE

Baker, Matthew R.; Swanson, Penny; Young, Graham

2013-01-01

Exploitation of fisheries resources has unintended consequences, not only in the bycatch and discard of non-target organisms, but also in damage to targeted fish that are injured by gear but not landed (non-retention). Delayed mortality due to non-retention represents lost reproductive potential in exploited stocks, while not contributing to harvest. Our study examined the physiological mechanisms by which delayed mortality occurs and the extent to which injuries related to disentanglement fr...

A Job Retention Model for Individuals with Mental Retardation

Science.gov (United States)

Fornes, Sandra

2006-01-01

This structured literature review examines the literature and addresses issues of job retention for adult workers with moderate to mild mental retardation (MR), investigating the relationships between work-related social behaviors, self-determination, person-job congruency of individuals with MR, and their job performance and job satisfaction with…

Absorption and retention of nickel from drinking water in relation to food intake and nickel sensitivity.

Science.gov (United States)

Nielsen, G D; Søderberg, U; Jørgensen, P J; Templeton, D M; Rasmussen, S N; Andersen, K E; Grandjean, P

1999-01-01

Two studies were performed to examine the influence of fasting and food intake on the absorption and retention of nickel added to drinking water and to determine if nickel sensitization played any role in this regard. First, eight nonallergic male volunteers fasted overnight before being given nickel in drinking water (12 micrograms Ni/kg) and, at different time intervals, standardized 1400-kJ portions of scrambled eggs. When nickel was ingested in water 30 min or 1 h prior to the meal, peak nickel concentrations in serum occurred 1 h after the water intake, and the peak was 13-fold higher than the one seen 1 h after simultaneous intake of nickel-containing water and scrambled eggs. In the latter case, a smaller, delayed peak occurred 3 h after the meal. Median urinary nickel excretion half-times varied between 19.9 and 26.7 h. Within 3 days, the amount of nickel excreted corresponded to 2.5% of the nickel ingested when it was mixed into the scrambled eggs. Increasing amounts were excreted as the interval between the water and the meal increased, with 25.8% of the administered dose being excreted when the eggs were served 4 h prior to the nickel-containing drinking water. In the second experiment, a stable nickel isotope, 61Ni, was given in drinking water to 20 nickel-sensitized women and 20 age-matched controls, both groups having vesicular hand eczema of the pompholyx type. Nine of 20 nickel allergic eczema patients experienced aggravation of hand eczema after nickel administration, and three also developed a maculopapular exanthema. No exacerbation was seen in the control group. The course of nickel absorption and excretion in the allergic groups did not differ and was similar to the pattern seen in the first study, although the absorption in the women was less. A sex-related difference in gastric emptying rates may play a role. Thus, food intake and gastric emptying are of substantial significance for the bioavailability of nickel from aqueous solutions

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)

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.

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...

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

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 ...

Pennsylvania Academic Libraries and Student Retention and Graduation: A Preliminary Investigation with Confusing Results

Directory of Open Access Journals (Sweden)

Gregory A. Crawford

2014-11-01

Full Text Available This study examined the relationships between specific institutional financial variables and two library-related variables on graduation and retention rates for colleges and universities through correlations and multiple regression analysis. The analyses used data for Pennsylvania colleges and universities that were extracted from the Integrated Postsecondary Educational Data System (IPEDS and the Academic Libraries Survey (ALS.  All analyses were run using IBM SPSS software. The correlations showed that both library expenses per student and library use per student were significantly correlated with both graduation and retention rates. In contrast, the multiple regression results showed that neither library budgets nor library use had significant effects on either graduation rates or retention rates. As would be expected, instructional expenses per student had the highest correlation with both graduation and retention and also yielded the strongest coefficient in the resulting regression equations.

Modeling mixed retention and early arrivals in multidimensional heterogeneous media using an explicit Lagrangian scheme

Science.gov (United States)

Zhang, Yong; Meerschaert, Mark M.; Baeumer, Boris; LaBolle, Eric M.

2015-08-01

This study develops an explicit two-step Lagrangian scheme based on the renewal-reward process to capture transient anomalous diffusion with mixed retention and early arrivals in multidimensional media. The resulting 3-D anomalous transport simulator provides a flexible platform for modeling transport. The first step explicitly models retention due to mass exchange between one mobile zone and any number of parallel immobile zones. The mobile component of the renewal process can be calculated as either an exponential random variable or a preassigned time step, and the subsequent random immobile time follows a Hyper-exponential distribution for finite immobile zones or a tempered stable distribution for infinite immobile zones with an exponentially tempered power-law memory function. The second step describes well-documented early arrivals which can follow streamlines due to mechanical dispersion using the method of subordination to regional flow. Applicability and implementation of the Lagrangian solver are further checked against transport observed in various media. Results show that, although the time-nonlocal model parameters are predictable for transport with retention in alluvial settings, the standard time-nonlocal model cannot capture early arrivals. Retention and early arrivals observed in porous and fractured media can be efficiently modeled by our Lagrangian solver, allowing anomalous transport to be incorporated into 2-D/3-D models with irregular flow fields. Extensions of the particle-tracking approach are also discussed for transport with parameters conditioned on local aquifer properties, as required by transient flow and nonstationary media.

Shade and flow effects on ammonia retention in macrophyte-rich streams: implications for water quality

International Nuclear Information System (INIS)

Wilcock, Robert J.; Scarsbrook, Mike R.; Cooke, James G.; Costley, Kerry J.; Nagels, John W.

2004-01-01

Controlled releases of NH 4 -N and conservative tracers (Br - and Cl - ) to five reaches of four streams with contrasting macrophyte communities have shown differing retentions, largely as a result of the way plants interact with stream flow and velocity. First-order constants (k) were 1.0-4.8 d -1 and retention of NH 4 -N was 6-71% of amounts added to each reach. Distance travelled before a 50% reduction in concentration was achieved were 40-450 m in three streams under low-flow conditions, and 2400-3800 m at higher flows. Retention (%) of NH 4 -N can be approximated by a simple function of travel time and k, highlighting the importance of the relationship between macrophytes and stream velocity on nutrient processing. This finding has significant management implications, particularly with respect to restoration of riparian shade. Small streams with predominantly marginal emergent plants are likely to have improved retention of NH 4 -N as a result of shading or other means of reducing plant biomass. Streams dominated by submerged macrophytes will have impaired NH 4 -N retention if plant biomass is reduced because of reduced contact times between NH 4 -N molecules and reactive sites. In these conditions water resource managers should utilise riparian shading in concert with unshaded vegetated reaches to achieve a balance between enhanced in-stream habitat and nutrient processing capacity

A case of urinary retention in the early stages of herpes simplex virus type-1 encephalitis.

Science.gov (United States)

Fukuoka, Takuya; Nakazato, Yoshihiko; Miyake, Akifumi; Tamura, Naotoshi; Araki, Nobuo; Yamamoto, Toshimasa

2017-06-01

A 70-year-old man developed urinary retention in the early stages of herpes simplex virus (HSV) type-1 encephalitis. A nerve conduction study suggested latent myeloradiculitis. This is the first report of human herpes simplex virus-1 encephalitis followed by urinary retention at early stage from the onset like the Elsberg syndrome. Although relatively few similar cases have been reported, we consider that urinary retention is common in HSV-1 encephalitis, in which disturbances of consciousness usually require bladder catheterization from the onset. We further emphasize that urinary retention may occasionally occur in early stages of HSV-1 encephalitis, with a significant possibility of recovery. Copyright © 2017. Published by Elsevier B.V.

Carbon transport and fuel retention in JT-60U with high temperature operation based on postmortem analysis

Energy Technology Data Exchange (ETDEWEB)

Yoshida, M., E-mail: yoshida.masafumi@jaea.go.jp [Japan Atomic Energy Agency, Mukoyama 801-1, Naka-shi, Ibaraki-ken 311-0193 (Japan); Tanabe, T.; Adachi, A. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Hayashi, T.; Nakano, T.; Fukumoto, M.; Yagyu, J.; Miyo, Y.; Masaki, K.; Itami, K. [Japan Atomic Energy Agency, Mukoyama 801-1, Naka-shi, Ibaraki-ken 311-0193 (Japan)

2013-07-15

Fuel retention rates and carbon re-deposition rates in the plasma shadowed areas, or tile gaps and remote areas, in JT-60U were measured. The total fuel retention rate in the plasma shadowed areas was more than two times higher than that in the carbon re-deposited layers on the plasma facing surfaces, or the divertor tiles. This is because of lower temperature in the plasma shadowed areas than in the plasma facing surfaces, which leads to high hydrogen saturation concentration, although the amount of the carbon re-deposited on the plasma shadowed areas was only 60% of that on the plasma facing surfaces. The total fuel retention rate in JT-60U, including previously determined for all the plasma facing areas, was evaluated to be 1.3 × 10{sup 20} H + D s{sup −1}, and this retention rate was lower than that in the other devices, due probably to high baking temperature operation in JT-60U. Distributions of the fuel retention and the carbon re-deposition in the whole in-vessel of a large tokamak were determined for the first time in the world.

Carbon transport and fuel retention in JT-60U with high temperature operation based on postmortem analysis

International Nuclear Information System (INIS)

Yoshida, M.; Tanabe, T.; Adachi, A.; Hayashi, T.; Nakano, T.; Fukumoto, M.; Yagyu, J.; Miyo, Y.; Masaki, K.; Itami, K.

2013-01-01

Fuel retention rates and carbon re-deposition rates in the plasma shadowed areas, or tile gaps and remote areas, in JT-60U were measured. The total fuel retention rate in the plasma shadowed areas was more than two times higher than that in the carbon re-deposited layers on the plasma facing surfaces, or the divertor tiles. This is because of lower temperature in the plasma shadowed areas than in the plasma facing surfaces, which leads to high hydrogen saturation concentration, although the amount of the carbon re-deposited on the plasma shadowed areas was only 60% of that on the plasma facing surfaces. The total fuel retention rate in JT-60U, including previously determined for all the plasma facing areas, was evaluated to be 1.3 × 10 20 H + D s −1 , and this retention rate was lower than that in the other devices, due probably to high baking temperature operation in JT-60U. Distributions of the fuel retention and the carbon re-deposition in the whole in-vessel of a large tokamak were determined for the first time in the world

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

Effect of molecular interactions on retention and selectivity in reversed-phase liquid chromatography.

Science.gov (United States)

Szepesy, László

2002-06-25

The linear solvation energy relationships (LSERs) have been applied in the last years for description and prediction of retention and selectivity in reversed-phase liquid chromatography with good results. Widely different stationary phases have been compared and characterized by LSERs. In recent publications the influence of the type of the organic moderator and the composition of the mobile phase have also been described. However, the influence of the molecular properties of the solutes to be separated has never been discussed. According to the LSER model variation in retention factors (log k) with solute structure can be related to their potential for various intermolecular interactions. The retention factor is given as the sum of the terms of the LSER equation representing various types of molecular interactions. For this reason the influence of the structure and molecular properties of the solutes to be separated can also be investigated using the LSER equation. In this study we shall demonstrate how the specific molecular interactions influence chromatographic retention and selectivity. We intend to show that retention and selectivity depend on all participants of the system. In addition to the structure and properties of the stationary phase and the type and composition of the mobile phase the molecular properties of the solutes, characterized by the solvation parameters, will also influence the type and extent of the various molecular interactions governing retention and selectivity.

Retention period after treatment of posterior crossbite with maxillary expansion: a systematic review

Directory of Open Access Journals (Sweden)

Julia Garcia Costa

Full Text Available ABSTRACT OBJECTIVE: The aim of this systematic review was to evaluate the duration of the retention period in growing patients undergoing maxillary expansion and its relation with posterior crossbite stability. METHODS: Search strategies were executed for electronic databases Cochrane Library, Web of Science, PubMed and Scopus, which were completed on January 15, 2016. The inclusion criteria included randomized, prospective or retrospective controlled trials in growing subjects with posterior crossbite; treated with maxillary expanders; retention phase after expansion; post-retention phase of at least 6 months. The exclusion criteria were anterior crossbite, craniofacial anomalies, surgery or another orthodontic intervention; case reports; author’s opinions articles, thesis, literature reviews and systematic reviews. The risk of bias of selected articles was assessed with Cochrane risk of bias tool for RCTs and Downs and Black checklist for non-RCTs. RESULTS: A total of 156 titles/abstracts was retrieved, 44 full-texts were examined, and 6 articles were selected and assessed for their methodological quality. The retention period after maxillary expansion ranged between 4 weeks and 16 months. Fixed (acrylic plate, Haas, Hyrax and quad-helix or removable (Hawley and Hawley expander appliances were used for retention. CONCLUSIONS: Six months of retention with either fixed or removable appliances seem to be enough to avoid relapse or to guarantee minimal changes in a short-term follow-up.

An integrated dataset on organisational retention attributes and commitment of selected ICT and accounting firms

Directory of Open Access Journals (Sweden)

Odunayo Salau

2018-06-01

Full Text Available The article presented an integrated data on organisational retention strategies and commitment of selected ICT and Accounting firms in Nigeria. The study adopted a quantitative approach with a survey research design to establish the major determinants of employee retention strategies. The population of this study included staff and management of the selected firms. Data was analysed with the use of structural equation modelling and the field data set is made widely accessible to enable critical or a more comprehensive investigation. The findings identified critical attraction factors for the retention of sampled firms. It was recommended that ICT firms will need to adopt consistent range of strategies to attract and retain people with the right ICT skills, in the right place and at the right time. Keywords: Retention, Commitment, Reward, Satisfaction, Performance

Safety of systems for the retention of wastes containing radionuclides

International Nuclear Information System (INIS)

1980-11-01

Information and minimal requirements demanded by CNEN for the emission of the Approval Certificate of the Safety Analysis Report related to system for the retention of wastes containing radionuclide, are established, aiming to assure low radioactivity levels to the environment. (E.G.) [pt

Geoecological controls on net mercury retention in northern peatlands

Science.gov (United States)

Bindler, R.; Rydberg, J.

2010-12-01

Peatlands, which receive much or all of their element inputs (e.g. nutrients or trace metals) via the atmosphere, are considered an ideal archive for studying past changes in mercury (Hg) deposition. These archives potentially contain information not only on important anthropogenic contributions to the environment over the past few centuries, but also on the natural antecedent conditions over the past several millennia. However, the assumption that Hg accumulation rates in peat represent an absolute record of past atmospheric deposition has proved problematic. In on-going studies of Hg retention in northern peatlands (bogs and oligotrophic fens) we find that net Hg accumulation is influenced by a range of geoecological factors in addition to actual changes in atmospheric deposition. Factors that influence the interception and net retention of Hg include differences in vegetation and microtopography - both of which may enhance dry deposition, and properties and processes within the peat such as decomposition that might influence long-term retention. Wetness, too, may play an important role in net retention in the surface peat through increased evasive losses of Hg. Differences between Hg concentrations in vascular plants and mosses are well established (at our site: 5-15 ng/g for leaves/needles of cottongrass, heather, Labrador tea and pine; 15-45 ng/g for mosses Sphagnum centrale and S. rubellum), but we also measured significant differences between different mosses within the same plots (S. rubellum, 24±3 ng/g; S. centrale, 18±2 ng/g). Further differences in Hg concentrations occur for single moss species in different settings; for example, Hg concentrations in S. centrale in open Sphagnum-only plots relative to plots including a mixture of vascular plants that form a field-layer canopy are 18±2 and 32±6 ng/g, respectively. As a result, sampling sites consisting of both Sphagnum and vascular plants have long-term cumulative inventories of mercury in the peat

The Retention of Meaningful Understanding of Meiosis and Genetics.

Science.gov (United States)

Cavallo, Ann Liberatore

This study investigated the retention of meaningful understanding of the biological topics of meiosis, the Punnett square method and the relations between these two topics. This study also explored the predictive influence of students' general tendency to learn meaningfully or by rote (meaningful learning orientation), prior knowledge of meiosis,…

Quantitative assessment of radionuclide retention in the near-surface system at Forsmark. Development of a reactive transport model using Forsmark 1.2 data

International Nuclear Information System (INIS)

Grandia, Fidel; Sena, Clara; Arcos, David; Molinero, Jorge; Duro, Lara; Bruno, Jordi

2007-12-01

The main objective of this work is to assess the migration behaviour of selected long-lived radionuclides through the near-surface system of Forsmark, with special focus on the evaluation of the capacity of the Quaternary deposits and sediments for radionuclide retention. The work reported here is based on data and information from Forsmark Site Descriptive Model version 1.2. From the geological point of view, the near-surface systems in the Forsmark area consist of Quaternary deposits and sediments that overlay the granitic bedrock. Glacial till is the more abundant outcropping Quaternary deposit and the remainder is made of clayey deposits. These types of near-surface sediments show distinctive hydraulic and geochemical features. The main reactive mineral in the till deposits, for the time horizons considered in this work, is calcium carbonate together with minor amounts of clay minerals (e.g. illite). The till deposits forms aquifers with relatively high hydraulic conductivities. In contrast, glacial and post-glacial clays are basically composed of illite with low to very low amounts of calcium carbonate, and containing organic matter-rich layers (gyttja), which can promote reducing conditions in the porewaters. All these clays exhibits relatively low hydraulic conductivity values. Five radionuclides have been selected for conceptualization and qualitative evaluation of retention process: U as an actinide, Se as a redox-sensitive radionuclide, Cs as a monovalent cation, Sr as a divalent cation, and I as an anion radionuclide. Overall, radionuclide retention capacity in the surface systems at Forsmark can be provided by sorption on charged surfaces of clays and oxyhydroxides, co-precipitation with sulphates, sulphides, oxyhydroxides and carbonates, and sorption on organic matter. Two-dimensional coupled hydrogeological and reactive solute transport models have been developed to simulate the geochemical behaviour of U, Cs and Sr. These three radionuclides have

SILICON CARBIDE GRAIN BOUNDARY DISTRIBUTIONS, IRRADIATION CONDITIONS, AND SILVER RETENTION IN IRRADIATED AGR-1 TRISO FUEL PARTICLES

Energy Technology Data Exchange (ETDEWEB)

Lillo, T. M.; Rooyen, I. J.; Aguiar, J. A.

2016-11-01

Precession electron diffraction in the transmission electron microscope was used to map grain orientation and ultimately determine grain boundary misorientation angle distributions, relative fractions of grain boundary types (random high angle, low angle or coincident site lattice (CSL)-related boundaries) and the distributions of CSL-related grain boundaries in the SiC layer of irradiated TRISO-coated fuel particles. Two particles from the AGR-1 experiment exhibiting high Ag-110m retention (>80%) were compared to a particle exhibiting low Ag-110m retention (<19%). Irradiated particles with high Ag-110m retention exhibited a lower fraction of random, high angle grain boundaries compared to the low Ag-110m retention particle. An inverse relationship between the random, high angle grain boundary fraction and Ag-110m retention is found and is consistent with grain boundary percolation theory. Also, comparison of the grain boundary distributions with previously reported unirradiated grain boundary distributions, based on SEM-based EBSD for similarly fabricated particles, showed only small differences, i.e. a greater low angle grain boundary fraction in unirradiated SiC. It was, thus, concluded that SiC layers with grain boundary distributions susceptible to Ag-110m release were present prior to irradiation. Finally, irradiation parameters were found to have little effect on the association of fission product precipitates with specific grain boundary types.

Fractional intestinal absorption and retention of calcium measured by whole-body counting. Application of a power function model

International Nuclear Information System (INIS)

Pors Nielsen, S.; Baerenholdt, O.; Munck, O.

1975-01-01

By application of a power function model, fractional intestinal calcium absorption was investigated with a new technique involving whole-body counting after successive oral and intravenous administration of standard doses of 47 Ca. The fractional calcium retention 7 days after the oral load of 47 Ca was also measured. Fractional calcium retention averaged 30.3% in normal subjects and 11.5% in 11 patients with intestinal malabsorption. In the same groups fractional calcium absorption averaged 46.6% and 16.4%, respectively. Fractional calcium retention and intestinal calcium absorption were significantly correlated to body surface area, and there was a well-defined relation between fractional retention and absorption of calcium. These studies demonstrate that measurements of fractional retention and fractional intestinal absorption of calcium can be combined by the use of a whole-body counter, that fractional retention and intestinal absorption are proportional to total body surface area and therefore probably also to the total bone mass, and that fractional retention and absorption are so closely interrelated that frational absorption can be estimated from fractional retention with reasonable accuracy in normal subjects. (auth.)

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.

Inhaled hyaluronic acid microparticles extended pulmonary retention and suppressed systemic exposure of a short-acting bronchodilator

DEFF Research Database (Denmark)

Li, Ying; Han, Meihua; Liu, Tingting

2017-01-01

The aim of this study was to investigate the feasibility of using hyaluronic acid (HA), a biomucoadhesive carbohydrate polymer to prolong the pulmonary retention and reduce the systemic exposure of inhaled medicine. Salbutamol sulphate (SAS), a model bronchodilator, was co-spray dried with HA...... to spray-dried plain SAS powders, the SAS-loaded HA microparticles possessed enhanced biomucoadhesive property in vitro and had much longer pulmonary retention and reduced systemic exposure in vivo. By incorporation, the pulmonary retention time of SAS was prolonged from 2h to 8h while the maximum...

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.

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,