The thermodynamic water retention capacity of solutions and gels.

Science.gov (United States)

Borchard, W; Jablonski, P

2003-01-01

The thermodynamic water retention capacity (WRC) has been defined and applied to different heterogeneous phase equilibria. This definition includes others known from the literature for testing heterogeneous systems. For the type of a real solution it is shown that at constant values of temperature and pressure the WRC is related to the difference of the chemical potential of water between the original state and the state after having applied a constraint. The dependence of WRC on concentration of a solute is predicted to be described by an e-function which has been experimentally confirmed in the literature.

Analysis of change of retention capacity of a small water reservoir

Science.gov (United States)

Výleta, R.; Danáčová, M.; Valent, P.

2017-10-01

This study is focused on the analysis of the changes of retention capacity of a small water reservoir induced by intensive erosion and sedimentation processes. The water reservoir is situated near the village of Vrbovce in the Western part of Slovakia, and the analysis is carried out for a period 2008-2017. The data used to build a digital elevation model (DEM) of the reservoir’s bed came from a terrain measurement, utilizing an acoustic Doppler current profiler (ADCP) to measure the water depth in the reservoir. The DEM was used to quantify the soil loss from agricultural land situated within the basin of the reservoir. The ability of the water reservoir to transform a design flood with a return period of 100 years is evaluated for both design (2008) and current conditions (2017). The results show that the small water reservoir is a subject to siltation, with sediments comprised of fine soil particles transported from nearby agricultural land. The ability of the water reservoir to transform a 100-year flood has not changed significantly. The reduction of the reservoir’s retention capacity should be systematically and regularly monitored in order to adjust its operational manual and improve its efficiency.

Instructional Interventions and Affective Beliefs as Predictors of Achievement and Retention of Learning

Directory of Open Access Journals (Sweden)

Ambrose Hans G. Aggabao

2015-11-01

Full Text Available Path and factor analyses were used in this study to investigate direct and indirect influences of instructional interventions on achievement and retention of learning among freshmen students in Mathematics as mediated by affective beliefs. The varying classroom contexts were hypothesized to influence affective beliefs through the application of varying instructional interventions – traditional teaching, radical constructivist, and social constructivist. The randomized equivalent groups pre-posttest experimental design was used to generate the needed data for analysis. Results showed that constructivist instructional approaches directly and indirectly influenced achievement measures with the indirect effects mediated by control orientation belief of students which was found to be the only one among four affective beliefs considered in this study to influence achievement measures. Social constructivist interventions did not show direct influence on retention of conceptual understanding and procedural fluency while traditional instructional intervention was not found to be a significant predictor of both affective beliefs and achievement measures.These results confirm for the most part the hypothesized relations among instructional interventions, affective beliefs, and achievement measures.

Load-Bearing Capacity and Retention of Newly Developed Micro-Locking Implant Prosthetic System: An In Vitro Pilot Study

Directory of Open Access Journals (Sweden)

Jae-Won Choi

2018-04-01

Full Text Available The aim of this study was to introduce the newly developed micro-locking implant prosthetic system and to evaluate the resulting its characteristics. To evaluate load-bearing capacity, 25 implants were divided into five groups: external-hexagon connection (EH, internal-octagon connection (IO, internal-hexagon connection (IH, one-body implant (OB, micro-locking implant system (ML. The maximum compressive load was measured using a universal testing machine (UTM according to the ISO 14801. Retention was evaluated in two experiments: (1 a tensile test of the structure modifications of the components (attachment and implant and (2 a tensile test after cyclic loading (total 5,000,000 cycles, 100 N, 2 Hz. The load-bearing capacity of the ML group was not significantly different from the other groups (p > 0.05. The number of balls in the attachment and the presence of a hexagonal receptacle did not show a significant correlation with retention (p > 0.05, but the shape of the retentive groove in the implant post had a statistically significant effect on retention (p < 0.05. On the other hand, the retention loss was observed during the initial 1,000,000 cycles, but an overall constant retention was maintained afterward. Various preclinical studies on this novel micro-locking implant prosthetic system should continue so that it can be applied in clinical practice.

Depth Filters Containing Diatomite Achieve More Efficient Particle Retention than Filters Solely Containing Cellulose Fibers.

Science.gov (United States)

Buyel, Johannes F; Gruchow, Hannah M; Fischer, Rainer

2015-01-01

The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g., when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m(-2) when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU) when diatomite filters were used. We also tested pre-coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m(-2) with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins.

Depth filters containing diatomite achieve more efficient particle retention than filters solely containing cellulose fibers

Directory of Open Access Journals (Sweden)

Johannes Felix Buyel

2015-12-01

Full Text Available The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g. when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m-2 when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU when diatomite filters were used. We also tested pre coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m-2 with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins.

Use of Fe/Al drinking water treatment residuals as amendments for enhancing the retention capacity of glyphosate in agricultural soils.

Science.gov (United States)

Zhao, Yuanyuan; Wendling, Laura A; Wang, Changhui; Pei, Yuansheng

2015-08-01

Fe/Al drinking water treatment residuals (WTRs), ubiquitous and non-hazardous by-products of drinking water purification, are cost-effective adsorbents for glyphosate. Given that repeated glyphosate applications could significantly decrease glyphosate retention by soils and that the adsorbed glyphosate is potentially mobile, high sorption capacity and stability of glyphosate in agricultural soils are needed to prevent pollution of water by glyphosate. Therefore, we investigated the feasibility of reusing Fe/Al WTR as a soil amendment to enhance the retention capacity of glyphosate in two agricultural soils. The results of batch experiments showed that the Fe/Al WTR amendment significantly enhanced the glyphosate sorption capacity of both soils (pretention capacity in soils. Copyright © 2015. Published by Elsevier B.V.

Evaluation of tritiated water retention capacity of fusion reactor concrete building

International Nuclear Information System (INIS)

Numata, S.; Fujii, Y.; Okamoto, M.

1992-01-01

In this paper the diffusion of tritiated water vapor into concrete walls is studied to evaluate tritiated water retention capacity of a fusion reactor concrete building. Using a model of the tritiated water diffusion determined form experimental results, depth profiles of tritiated water in concrete are calculated in the case of being exposed to air containing tritiated water vapor during the normal operational condition of a fusion reactor. A 0.5-m-thick concrete is sufficient for reactor hall walls from a viewpoint of the tritium containment

Effects of Computer-Assisted Jigsaw II Cooperative Learning Strategy on Physics Achievement and Retention

Science.gov (United States)

Gambari, Isiaka Amosa; Yusuf, Mudasiru Olalere

2016-01-01

This study investigated the effects of computer-assisted Jigsaw II cooperative strategy on physics achievement and retention. The study also determined how moderating variables of achievement levels as it affects students' performance in physics when Jigsaw II cooperative learning is used as an instructional strategy. Purposive sampling technique…

"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

Suitability of adsorption isotherms for predicting the retention capacity of active slag filters removing phosphorus from wastewater.

Science.gov (United States)

Pratt, C; Shilton, A

2009-01-01

Active slag filters are an emerging technology for removing phosphorus (P) from wastewater. A number of researchers have suggested that adsorption isotherms are a useful tool for predicting P retention capacity. However, to date the appropriateness of using isotherms for slag filter design remains unverified due to the absence of benchmark data from a full-scale, field filter operated to exhaustion. This investigation compared the isotherm-predicted P retention capacity of a melter slag with the P adsorption capacity determined from a full-scale, melter slag filter which had reached exhaustion after five years of successfully removing P from waste stabilization pond effluent. Results from the standard laboratory batch test showed that P adsorption correlated more strongly with the Freundlich Isotherm (R(2)=0.97, Pretention capacity of 0.014 gP/kg slag; markedly lower than the 1.23 gP/kg slag adsorbed by the field filter. Clearly, the result generated by the isotherm bears no resemblance to actual field capacity. Scanning electron microscopy analysis revealed porous, reactive secondary minerals on the slag granule surfaces from the field filter which were likely created by weathering. This slow weathering effect, which generates substantial new adsorption sites, is not accounted for by adsorption isotherms rendering them ineffective in slag filter design.

The Effects of Cooperative Learning on the Academic Achievement and Knowledge Retention

Science.gov (United States)

Tran, Van Dat

2014-01-01

This experimental study investigated the effects of cooperative learning on the achievement and knowledge retention of 110 first-year primary education students toward the psychology subject over the eight weeks of instruction at An Giang University. These tertiary students were divided into two matched groups of 55 to be taught by the same…

Correlating Lithium Hydroxyl Accumulation with Capacity Retention in V2O5 Aerogel Cathodes.

Science.gov (United States)

Wangoh, Linda W; Huang, Yiqing; Jezorek, Ryan L; Kehoe, Aoife B; Watson, Graeme W; Omenya, Fredrick; Quackenbush, Nicholas F; Chernova, Natasha A; Whittingham, M Stanley; Piper, Louis F J

2016-05-11

V2O5 aerogels are capable of reversibly intercalating more than 5 Li(+)/V2O5 but suffer from lifetime issues due to their poor capacity retention upon cycling. We employed a range of material characterization and electrochemical techniques along with atomic pair distribution function, X-ray photoelectron spectroscopy, and density functional theory to determine the origin of the capacity fading in V2O5 aerogel cathodes. In addition to the expected vanadium redox due to intercalation, we observed LiOH species that formed upon discharge and were only partially removed after charging, resulting in an accumulation of electrochemically inactive LiOH over each cycle. Our results indicate that the tightly bound water that is necessary for maintaining the aerogel structure is also inherently responsible for the capacity fade.

Use of in situ volumetric water content at field capacity to improve prediction of soil water retention properties

OpenAIRE

Al Majou , Hassan; Bruand , Ary; Duval , Odile

2008-01-01

International audience; Use of in situ volumetric water content at field capacity to improve prediction of soil water retention properties. Most pedotransfer functions (PTFs) developed over the last three decades to generate water retention characteristics use soil texture, bulk density and organic carbon content as predictors. Despite of the high number of PTFs published, most being class- or continuous-PTFs, accuracy of prediction remains limited. In this study, we compared the performance ...

Analysis of the temperature effect on the water retention capacity of soil using a thermodynamic approach

International Nuclear Information System (INIS)

Jacinto, A.C.; Ledesma, A.; Villar, M.V.

2012-01-01

between the amount adsorbed and the pressure is called the adsorption isotherm. In Geotechnical Engineering, the adsorption isotherm for a given soil is called the soil water retention curve (SWRC). SWRC defines the constitutive relationship between the amount of water in the soil and the suction. The amount of water in the soil can be given in terms of gravimetric water content , volumetric water content , or degree of saturation . To be useful in modeling processes, a continuous representation of the SWRC is required and needs to be incorporated in predictive models. Several mathematical equations have been proposed to describe the soil water retention curve. Many expressions proposed for the SWRC are mainly based on pore size distribution functions in combination with the concept of bundle of capillaries, in which the pores are represented by cylindrical capillary tubes obeying the Young and Laplace equation. The capillary model, although very intuitive, gives only a first approximation to interpret the effect of variables like temperature on the suction, as capillarity only represents one of the mechanisms by which soil is able to hold water in its voids. A more powerful tool is obtained when thermodynamic concepts of interfacial phenomena are considered to analyse the physical adsorption of water by soils. Surface thermodynamics is able to explain the physical adsorption of thin films on solid surface but its application to porous materials is of very limited utility because of the complex geometry of the interfaces in the case of soils. On the other hand, the thermodynamics of adsorption can be treated as a special case of solution thermodynamics for which the adsorbates are the solutes and the adsorbent is the solvent. Experimental results show that the water retention capacity of soil tends to reduce with increasing temperature. Traditionally, the temperature effect was analysed following the idea proposed by Philip and de Vries (1957) which suggested that changes

Achievable capacity of a spectrum sharing system over hyper fading channels

KAUST Repository

Ekin, Sabit

2009-11-01

Cognitive radio with spectrum sharing feature is a promising technique to address the spectrum under-utilization problem in dynamically changing environments. In this paper, achievable capacity gain of spectrum sharing systems over dynamic fading environments is studied. For the analysis, a theoretical fading model called hyper fading model that is suitable to the dynamic nature of cognitive radio channel is proposed. Closed-form expression of probability density function (PDF) and cumulative density function (CDF) of the signal-to-noise ratio (SNR) for secondary users in spectrum sharing systems are derived. In addition, the capacity gains achievable with spectrum sharing systems in high and low power regions are obtained. Numerical simulations are performed to study the effects of different fading figures, average powers, interference temperature, and number of secondary users on the achievable capacity.

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

Process for retention of iodine and aerosols during containment venting

International Nuclear Information System (INIS)

Eckardt, B.; Betz, R.; Greger, G.U.; Werner, K.D.

1990-05-01

A process for retention of the majority of aerosols and iodine during containment venting was optimized. For this purpose, sections of a two-stage process comprising a venturi scrubber and a metal-fiber filter demister were tested under containment venting conditions assumed to prevail during a hypothetical core - melt accident and optimized with a view to achieving high decontamination factors and loading capacity while minimizing the size of the process. The loading and retention tests performed in a scrubber operating pressure range between 1 and 10 bar, at temperatures from 50 to 200degC (also boiling pools) and in air and steam atmospheres. Under these unfavorable conditions for aerosol retention, the retention efficiencies were determined at various flow rates with soluble and non-soluble aerosols as well as gaseous iodine. The retention efficiencies for BaSO 4 , uranine and SnO 2 aerosols were determined to be 99.95% to 99.99% for venturi scrubbers with metal-fiber filter demister. The retention efficiency for elemental iodine was determined to be ≥99% including revolatization effects over a 24-hour operating period. The high loading capacity of the venturi scrubber unit was verified after process modifications with various aerosols. The use of full-scale process section together with the best possible simulation of containment venting conditions by the test parameters ensured that the results can be transferred to real venting equipment. The aim of ensuring the retention of the majority of the aerosol-borne activity and of elemental iodine activity and minimizing the process size was clearly achieved and verified by means of this optimized venting equipment under an extremely wide range of hypothetical core-melt accident conditions. (orig.) With 17 refs., 3 tabs., 35 annexes [de

The Learning Community: A Program to Address Issues of Academic Achievement and Retention.

Science.gov (United States)

Hummel, Mary; Steele, Claude

1996-01-01

Describes the 21st Century Program at the University of Michigan, a program to address issues of academic achievement and student retention in higher education. The conceptual basis for this program comes from C. Steele's work that finds that there are disruptive pressures tied to racial stereotypes that in turn diminish academic performance. (SLD)

“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

Solvent Retention Capacities of Oat Flour

Directory of Open Access Journals (Sweden)

Qianwen Niu

2017-03-01

Full Text Available This study measured the solvent retention capacities (SRCs of flours from eight oat varieties and one wheat variety against different solvents to explore the swelling volume of oat flour with different solvents, and thus provide a theoretical basis for quick β-glucan analysis. The SRC profile consists of water SRC (WSRC, 50% sucrose SRC (SSRC, 5% lactic acid SRC (LASRC, 5% Na2CO3 SRC (SCASRC, NaCl SRC (SCSRC, CaCl2 SRC (CCSRC, FeCl3 SRC (FCSRC, sodium cholate SRC (SCHSRC, NaOH (pH 10 SRC (SHSRC, Na2CO3 (pH 10 SRC (SCABSRC and SDS (pH 10 SRC (SDSSRC values, and a Chopin SRC kit was used to measure the SRC value. SRCs of the oat flours increased when the solvents turned from neutral (water and NaCl to acidic (5% lactic acid or alkaline (5% Na2CO3, CaCl2, FeCl3, NaOH and pH 10 Na2CO3, and rose as the metal ion valencies of the metal salts (NaCl, CaCl2 and FeCl3 increased. The β-glucan contents were significantly positively correlated with the SCSRC (0.83**, CCSRC (0.82**, SCHSRC (0.80** and FCSRC (0.78*. SRC measurements of β-glucan in oat flours revealed that the CCSRC values were related with β-glucan (0.64* but not related with protein and starch. CaCl2 could therefore potentially be exploited as a reagent for β-glucan assay.

“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

Effects of an additional small group discussion to cognitive achievement and retention in basic principles of bioethics teaching methods

Directory of Open Access Journals (Sweden)

Dedi Afandi

2009-03-01

Full Text Available Aim The place of ethics in undergraduate medical curricula is essential but the methods of teaching medical ethics did not show substantial changes. “Basic principles of bioethics” is the best knowledge to develop student’s reasoning analysis in medical ethics In this study, we investigate the effects of an additional small group discussion in basic principles of bioethics conventional lecture methods to cognitive achievement and retention. This study was a randomized controlled trial with parallel design. Cognitive scores of the basic principles of bioethics as a parameter was measured using basic principles of bioethics (Kaidah Dasar Bioetika, KDB test. Both groups were attending conventional lectures, then the intervention group got an additional small group discussion.Result Conventional lectures with or without small group discussion significantly increased cognitive achievement of basic principles of bioethics (P= 0.001 and P= 0.000, respectively, and there were significant differences in cognitive achievement and retention between the 2 groups (P= 0.000 and P= 0.000, respectively.Conclusion Additional small group discussion method improved cognitive achievement and retention of basic principles of bioethics. (Med J Indones 2009; 18: 48-52Keywords: lecture, specification checklist, multiple choice questions

Does visual short-term memory have a high-capacity stage?

Science.gov (United States)

Matsukura, Michi; Hollingworth, Andrew

2011-12-01

Visual short-term memory (VSTM) has long been considered a durable, limited-capacity system for the brief retention of visual information. However, a recent work by Sligte et al. (Plos One 3:e1699, 2008) reported that, relatively early after the removal of a memory array, a cue allowed participants to access a fragile, high-capacity stage of VSTM that is distinct from iconic memory. In the present study, we examined whether this stage division is warranted by attempting to corroborate the existence of an early, high-capacity form of VSTM. The results of four experiments did not support Sligte et al.'s claim, since we did not obtain evidence for VSTM retention that exceeded traditional estimates of capacity. However, performance approaching that observed in Sligte et al. can be achieved through extensive practice, providing a clear explanation for their findings. Our evidence favors the standard view of VSTM as a limited-capacity system that maintains a few object representations in a relatively durable form.

The Effects of 3D Computer Simulation on Biology Students' Achievement and Memory Retention

Science.gov (United States)

Elangovan, Tavasuria; Ismail, Zurida

2014-01-01

A quasi experimental study was conducted for six weeks to determine the effectiveness of two different 3D computer simulation based teaching methods, that is, realistic simulation and non-realistic simulation on Form Four Biology students' achievement and memory retention in Perak, Malaysia. A sample of 136 Form Four Biology students in Perak,…

Educational Interface Agents as Social Models to Influence Learner Achievement, Attitude and Retention of Learning

Science.gov (United States)

Yilmaz, Ramazan; Kilic-Cakmak, Ebru

2012-01-01

This study examined the impacts of educational interface agents with different attributes on achievement, attitude and retention of elementary school students in their science and technology courses. The study was implemented in four different eighth- grade classes (aged 13-14) of an elementary school. Four different types of educational software,…

Effect of Learning Cycle Approach-Based Science Teaching on Academic Achievement, Attitude, Motivation and Retention

Science.gov (United States)

Uyanik, Gökhan

2016-01-01

The purpose of this study was to examine the effect of learning cycle approach-based teaching on academic achievement, attitude, motivation and retention at primary school 4th grade science lesson. It was conducted pretest-posttest quasi-experimental design in this study. The study was conducted on a total of 65 students studying in two different…

Reform-Based-Instructional Method and Learning Styles on Students' Achievement and Retention in Mathematics: Administrative Implications

Science.gov (United States)

Modebelu, M. N.; Ogbonna, C. C.

2014-01-01

This study aimed at determining the effect of reform-based-instructional method learning styles on students' achievement and retention in mathematics. A sample size of 119 students was randomly selected. The quasiexperimental design comprising pre-test, post-test, and randomized control group were employed. The Collin Rose learning styles…

Biodestruction of strongly swelling polymer hydrogels and its effect on the water retention capacity of soils

Science.gov (United States)

Smagin, A. V.; Sadovnikova, N. B.; Smagina, M. V.

2014-06-01

The biodestruction of strongly swelling polymer hydrogels (water adsorbing soil conditioners of the new generation) has been studied at the quantitative level using original mathematical models. In laboratory experiments, a relationship between the hydrogel degradation rate and the temperature has been obtained, and the effect of the biodestruction on the water retention curve of soil compositions with hydrogels (used as an index of their water retention capacity) has been assessed. From the automatic monitoring data of the temperature regime of soils, the potential biodestruction of hydrogels has been predicted for different climatic conditions. The loss of hydrogels during three months of the vegetation period because of destruction can exceed 30% of their initial content in irrigated agriculture under arid climatic conditions and more than 10% under humid climatic conditions. Thus, the biodestruction of hydrogels is one of the most important factors decreasing their efficiency under actual soil conditions.

Effect of divalent versus monovalent cations on the MS2 retention capacity of amino-functionalized ceramic filters.

Science.gov (United States)

Bartels, J; Hildebrand, N; Nawrocki, M; Kroll, S; Maas, M; Colombi Ciacchi, L; Rezwan, K

2018-04-25

Ceramic capillary membranes conditioned for virus filtration via functionalization with n-(3-trimethoxysilylpropyl)diethylenetriamine (TPDA) are analyzed with respect to their virus retention capacity when using feed solutions based on monovalent and divalent salts (NaCl, MgCl2). The log reduction value (LRV) by operating in dead-end mode using the model bacteriophage MS2 with a diameter of 25 nm and an IEP of 3.9 is as high as 9.6 when using feeds containing MgCl2. In contrast, a lesser LRV of 6.4 is observed for feed solutions based on NaCl. The TPDA functionalized surface is simulated at the atomistic scale using explicit-solvent molecular dynamics in the presence of either Na+ or Mg2+ ions. Computational prediction of the binding free energy reveals that the Mg2+ ions remain preferentially adsorbed at the surface, whereas Na+ ions form a weakly bound dissolved ionic layer. The charge shielding between surface and amino groups by the adsorbed Mg2+ ions leads to an upright orientation of the TPDA molecules as opposed to a more tilted orientation in the presence of Na+ ions. The resulting better accessibility of the TPDA molecules is very likely responsible for the enhanced virus retention capacity using a feed solution with Mg2+ ions.

Potential Water Retention Capacity as a Factor in Silage Effluent Control: Experiments with High Moisture By-product Feedstuffs.

Science.gov (United States)

Razak, Okine Abdul; Masaaki, Hanada; Yimamu, Aibibula; Meiji, Okamoto

2012-04-01

The role of moisture absorptive capacity of pre-silage material and its relationship with silage effluent in high moisture by-product feedstuffs (HMBF) is assessed. The term water retention capacity which is sometimes used in explaining the rate of effluent control in ensilage may be inadequate, since it accounts exclusively for the capacity of an absorbent incorporated into a pre-silage material prior to ensiling, without consideration to how much the pre-silage material can release. A new terminology, 'potential water retention capacity' (PWRC), which attempts to address this shortcoming, is proposed. Data were pooled from a series of experiments conducted separately over a period of five years using laboratory silos with four categories of agro by-products (n = 27) with differing moisture contents (highest 96.9%, lowest 78.1% in fresh matter, respectively), and their silages (n = 81). These were from a vegetable source (Daikon, Raphanus sativus), a root tuber source (potato pulp), a fruit source (apple pomace) and a cereal source (brewer's grain), respectively. The pre-silage materials were adjusted with dry in-silo absorbents consisting wheat straw, wheat or rice bran, beet pulp and bean stalks. The pooled mean for the moisture contents of all pre-silage materials was 78.3% (±10.3). Silage effluent decreased (p<0.01), with increase in PWRC of pre-silage material. The theoretical moisture content and PWRC of pre-silage material necessary to stem effluent flow completely in HMBF silage was 69.1% and 82.9 g/100 g in fresh matter, respectively. The high correlation (r = 0.76) between PWRC of ensiled material and silage effluent indicated that the latter is an important factor in silage-effluent relationship.

Achievable capacity of a spectrum sharing system over hyper fading channels

KAUST Repository

Ekin, Sabit; Yilmaz, Ferkan; Ç elebi, Hasari Burak; Qaraqe, Khalid A.; Alouini, Mohamed-Slim; Serpedin, Erchin

2009-01-01

Cognitive radio with spectrum sharing feature is a promising technique to address the spectrum under-utilization problem in dynamically changing environments. In this paper, achievable capacity gain of spectrum sharing systems over dynamic fading

The Effect of Concept Mapping-Guided Discovery Integrated Teaching Approach on Chemistry Students' Achievement and Retention

Science.gov (United States)

Fatokun, K. V. F.; Eniayeju, P. A.

2014-01-01

This study investigates the effects of Concept Mapping-Guided Discovery Integrated Teaching Approach on the achievement and retention of chemistry students. The sample comprised 162 Senior Secondary two (SS 2) students drawn from two Science Schools in Nasarawa State, Central Nigeria with equivalent mean scores of 9.68 and 9.49 in their pre-test.…

Adolescent reserve capacity, socioeconomic status and school achievement as predictors of mortality in Finland - a longitudinal study.

Science.gov (United States)

Acacio-Claro, Paulyn Jean; Koivusilta, Leena Kristiina; Borja, Judith Rafaelita; Rimpelä, Arja Hannele

2017-12-28

Despite robust evidence on the inverse relationship between socioeconomic status (SES) and mortality, deviations from expected results have been observed likely due to school achievement and psychosocial resources, termed as "reserve capacity." Since adolescence is a critical period in developing sound psychological and behavioural patterns and adolescent markers of SES were seldom used, we determine if family SES in adolescence predicts later mortality. We also study how reserve capacity (perceived health, health-promoting behaviour and social support) and school achievement modify this relationship and reduce the negative effects of low SES. A longitudinal study was designed by linking baseline data on 12 to 18 year-old Finns in 1985-95 (N = 41,833) from the Adolescent Health and Lifestyle Surveys with register data on mortality and SES from Statistics Finland. Average follow-up time was 18.4 years with a total of 770,161 person-years. Cox regression models, stratified by sex, were fitted to determine the effects of variables measured during adolescence: family SES, reserve capacity and school achievement on mortality risk. All reserve capacity dimensions significantly predicted mortality in boys. Perceived health and social support predicted that in girls. Adolescents with the lowest school achievement were more than twice at risk of dying compared to those with better school performance. Low SES increased the risk of death in boys (Hazard ratios: 1.6, 95% CI 1.1-2.4) but not in girls. Reserve capacity and school achievement weakened the effects of low SES on boys' risk of death. High reserve capacity and good school achievement in adolescence significantly reduce the risk of mortality. In boys, these also mitigate the negative effect of low SES on mortality. These findings underscore the roles of reserve capacity and school achievement during adolescence as likely causal or modifying factors in SES-health inequalities.

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.

The Effect of CTL Approach Based on NHT Learning Model toward Students’ motivation, Science Achievement, and Retention

Directory of Open Access Journals (Sweden)

Muhammad Mifta Fausan

2017-07-01

Full Text Available The learning is an interaction process between students and their environment in order to improve good behavior. The results of observation which has been done in grade V SDN No. 4 Tanjung Batu showed that the students’ motivation and science achievement were low. This was becaused by the learning process which was still product oriented (based on material content, consequently, this lead to limit the learning is merely on memorizing concept activities. One of the learning approach that can be used to solve this problem is the Contextual Teaching and Learning (CTL based on Numbered Head Together (NHT. This research aims to determine the effect of CTL based on NHT toward student’s motivation, science achievement, and retention. Subjects in this research were the students of grade V SDN No. 4 Tanjung Batu. This research is a quasi-experimental using post-test only control design. The data obtained were analyzed by using descriptive and inferential statistical analysis. The research instruments were observation sheets and written test. The results showed that there was significant effect of CTL based on NHT toward students’ motivation, science achievement, and retention. It can be seen from the independent sample t-test results which showed significant value less than 0.05.

Filtration and retention capacities of filter aids

International Nuclear Information System (INIS)

Mellah, A.; Boualia, A.

1992-01-01

The present work involves the filtration of impure uranyl nitrate solutions by different filter aids such as kieselguhr, celite and bleaching clay. The retention of substances contained in uranyl nitrate solution was determined using the three filter aids. A study of the effects of granulometry and filter earths treatment (thermal and chemical) on the filtration rate was performed

Effects of Creative Drama Method on Students' Attitude towards Social Studies, Academic Achievement and Retention in Turkey

Science.gov (United States)

Kaf, Ozlem; Yilmaz, Ozge Uygungul

2017-01-01

The purpose of this study was to investigate the effect of creative drama as a teaching method on academic achievement and retention in social studies, students' attitude towards social studies of 4th grade. The research is designed according to quasiexperimental model. The research was conducted with 4th year students in a public school in Adana…

The effect of A teacher questioning strategy training program on teaching behavior, student achievement, and retention

Science.gov (United States)

Otto, Paul B.; Schuck, Robert F.

The use of questions in the classroom has been employed throughout the recorded history of teaching. One still hears the term Socratic method during discussions of questioning procedures. The use of teacher questions is presently viewed as a viable procedure for effective instruction. This study was conducted to investigate the feasibility of training teachers in the use of a questioning technique and the resultant effect upon student learning. The Post-Test Only Control Group Design was used in randomly assigning teachers and students to experimental and control groups. A group of teachers was trained in the use of a specific questioning technique. Follow-up periodic observations were made of questioning technique behavior while teaching science units to groups of students. Post-unit achievement tests were administered to the student groups to obtain evidence of a relationship between the implementation of specific types of teacher questions and student achievement and retention. Analysis of observation data indicated a higher use of managerial and rhetorical questions by the control group than the experimental group. The experimental group employed a greater number of recall and data gathering questions as well as higher order data processing and data verification type questions. The student posttest achievement scores for both units of instruction were greater for the experimental groups than for the control groups. The retention scores for both units were Beater for the experimental groups than for the control groups.

Capacity retention in hydrogen storage alloys

Science.gov (United States)

Anani, A.; Visintin, A.; Srinivasan, S.; Appleby, A. J.; Reilly, J. J.; Johnson, J. R.

1992-01-01

Results of our examination of the properties of several candidate materials for hydrogen storage electrodes and their relation to the decrease in H-storage capacity upon open-circuit storage over time are reported. In some of the alloy samples examined to date, only about 10 percent of the hydrogen capacity was lost upon storage for 20 days, while in others, this number was as high as 30 percent for the same period of time. This loss in capacity is attributed to two separate mechanisms: (1) hydrogen desorbed from the electrode due to pressure differences between the cell and the electrode sample; and (2) chemical and/or electrochemical degradation of the alloy electrode upon exposure to the cell environment. The former process is a direct consequence of the equilibrium dissociation pressure of the hydride alloy phase and the partial pressure of hydrogen in the hydride phase in equilibrium with that in the electrolyte environment, while the latter is related to the stability of the alloy phase in the cell environment. Comparison of the equilibrium gas-phase dissociation pressures of these alloys indicate that reversible loss of hydrogen capacity is higher in alloys with P(eqm) greater than 1 atm than in those with P(eqm) less than 1 atm.

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.

Potential Water Retention Capacity as a Factor in Silage Effluent Control: Experiments with High Moisture By-product Feedstuffs

Science.gov (United States)

Razak, Okine Abdul; Masaaki, Hanada; Yimamu, Aibibula; Meiji, Okamoto

2012-01-01

The role of moisture absorptive capacity of pre-silage material and its relationship with silage effluent in high moisture by-product feedstuffs (HMBF) is assessed. The term water retention capacity which is sometimes used in explaining the rate of effluent control in ensilage may be inadequate, since it accounts exclusively for the capacity of an absorbent incorporated into a pre-silage material prior to ensiling, without consideration to how much the pre-silage material can release. A new terminology, ‘potential water retention capacity’ (PWRC), which attempts to address this shortcoming, is proposed. Data were pooled from a series of experiments conducted separately over a period of five years using laboratory silos with four categories of agro by-products (n = 27) with differing moisture contents (highest 96.9%, lowest 78.1% in fresh matter, respectively), and their silages (n = 81). These were from a vegetable source (Daikon, Raphanus sativus), a root tuber source (potato pulp), a fruit source (apple pomace) and a cereal source (brewer’s grain), respectively. The pre-silage materials were adjusted with dry in-silo absorbents consisting wheat straw, wheat or rice bran, beet pulp and bean stalks. The pooled mean for the moisture contents of all pre-silage materials was 78.3% (±10.3). Silage effluent decreased (p<0.01), with increase in PWRC of pre-silage material. The theoretical moisture content and PWRC of pre-silage material necessary to stem effluent flow completely in HMBF silage was 69.1% and 82.9 g/100 g in fresh matter, respectively. The high correlation (r = 0.76) between PWRC of ensiled material and silage effluent indicated that the latter is an important factor in silage-effluent relationship. PMID:25049587

Potential Water Retention Capacity as a Factor in Silage Effluent Control: Experiments with High Moisture By-product Feedstuffs

Directory of Open Access Journals (Sweden)

Okine Abdul Razak

2012-04-01

Full Text Available The role of moisture absorptive capacity of pre-silage material and its relationship with silage effluent in high moisture by-product feedstuffs (HMBF is assessed. The term water retention capacity which is sometimes used in explaining the rate of effluent control in ensilage may be inadequate, since it accounts exclusively for the capacity of an absorbent incorporated into a pre-silage material prior to ensiling, without consideration to how much the pre-silage material can release. A new terminology, ‘potential water retention capacity’ (PWRC, which attempts to address this shortcoming, is proposed. Data were pooled from a series of experiments conducted separately over a period of five years using laboratory silos with four categories of agro by-products (n = 27 with differing moisture contents (highest 96.9%, lowest 78.1% in fresh matter, respectively, and their silages (n = 81. These were from a vegetable source (Daikon, Raphanus sativus, a root tuber source (potato pulp, a fruit source (apple pomace and a cereal source (brewer’s grain, respectively. The pre-silage materials were adjusted with dry in-silo absorbents consisting wheat straw, wheat or rice bran, beet pulp and bean stalks. The pooled mean for the moisture contents of all pre-silage materials was 78.3% (±10.3. Silage effluent decreased (p<0.01, with increase in PWRC of pre-silage material. The theoretical moisture content and PWRC of pre-silage material necessary to stem effluent flow completely in HMBF silage was 69.1% and 82.9 g/100 g in fresh matter, respectively. The high correlation (r = 0.76 between PWRC of ensiled material and silage effluent indicated that the latter is an important factor in silage-effluent relationship.

Passive cooling effect of RC roof covered with the ceramics having high water retention and evaporation capacity

International Nuclear Information System (INIS)

Yamazaki, M; Kanaya, M; Shimazu, T; Ohashi, T; Kato, N; Horikoshi, T

2011-01-01

Hot days in metropolitan cities have increased remarkably by the heat island phenomenon these days. Thus the authors tried to develop the porous ceramics with high water retention and evaporation capacity as a maintenance-free material to improve thermal environment. The developed ceramic pellets have high water retention of more than 60% of water absorption and high water evaporation which is similar to water surface. In this study, three types of 5 meter squared large flat-roofed structural specimen simulated reinforced concrete (RC) slab were constructed on the outside. The variation of water content and temperature of the specimens and atmosphere temperature around the specimens were measured from summer in 2009. In the case of the ceramic pellets, the temperature under RC slab was around 15 deg. lower than that of the control. The results were probably contributed by passive cooling effect of evaporated rain water, and the effect was similar to in the case of the grasses. From the viewpoint of thermal environment improvement, substitution of a rooftop gardening by the porous ceramics could be a promising method.

Passive cooling effect of RC roof covered with the ceramics having high water retention and evaporation capacity

Energy Technology Data Exchange (ETDEWEB)

Yamazaki, M; Kanaya, M; Shimazu, T; Ohashi, T [INAX Corporation, 97-1, Yariba, Kume, Tokoname, Aichi, 479-0002 (Japan); Kato, N; Horikoshi, T, E-mail: m.yamazaki@i2.inax.co.jp [Department of Architecture, Nagoya Institute of technology, Gokiso-cho, Showa-ku, Nagoya, Aichi, 466-8555 (Japan)

2011-10-29

Hot days in metropolitan cities have increased remarkably by the heat island phenomenon these days. Thus the authors tried to develop the porous ceramics with high water retention and evaporation capacity as a maintenance-free material to improve thermal environment. The developed ceramic pellets have high water retention of more than 60% of water absorption and high water evaporation which is similar to water surface. In this study, three types of 5 meter squared large flat-roofed structural specimen simulated reinforced concrete (RC) slab were constructed on the outside. The variation of water content and temperature of the specimens and atmosphere temperature around the specimens were measured from summer in 2009. In the case of the ceramic pellets, the temperature under RC slab was around 15 deg. lower than that of the control. The results were probably contributed by passive cooling effect of evaporated rain water, and the effect was similar to in the case of the grasses. From the viewpoint of thermal environment improvement, substitution of a rooftop gardening by the porous ceramics could be a promising method.

The effect of teaching methods on cognitive achievement, retention, and attitude among in biology studying

Directory of Open Access Journals (Sweden)

Snezana Stavrova Veselinovskaa

2011-12-01

Full Text Available The purpose of this paper is to determine the effects of usage of sequential teaching method on the academic achievement and retention level of students. Three student groups of biology students in University “Goce Delcev”, Faculty of Natural and Technical Sciences, Institute of Biology, - Stip, R. Macedonia were offered a topic on general characteristics of Proteins: Their Biological Functions and Primary Structure with different sequences of 3 teaching methods. The teaching methods were Laboratory method (student experiment, slide demonstration and lecture method. The first group started to course with experiments in the laboratory, then the relevant theory of proteins was given lecture method, and then the slides was shown (Group I. The sequence of these three teaching methods used in the first group was changed in both second and third group as follow: The lecture methods, slide show and experiment in Group II, and slide show, experiment and lecture method in Group III, respectively. Laboratory method used in the study was focused on the topic of this diversity and abundance reflect the central role of proteins in virtually all aspects of cell structure and function. Achievement test contained 20 questions, testing the knowledge of facts as well as the ability to transfer the knowledge and problem solving ability. This test was used as pre-test before methods’ application, post-test after the methods’ application and retention test after 30 days from methods’ applied.

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

Effects of Information and Communication Technology (ICT) on Students' Academic Achievement and Retention in Chemistry at Secondary Level

Science.gov (United States)

Hussain, Ishtiaq; Suleman, Qaiser; ud Din, M. Naseer; Shafique, Farhan

2017-01-01

The current paper investigated the effects of information and communication technology on the students' academic achievement and retention in chemistry. Fifty students of 9th grade were selected randomly from Kohsar Public School and College Latamber Karak. The students were grouped into equivalent groups based on pretest score. In order to…

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

Microwave-assisted optimization of the manganese redox states for enhanced capacity and capacity retention of LiAl(subx)Mn(sub2-x)O(sub4) (x = 0 and 0.3) spinel materials

CSIR Research Space (South Africa)

Nkosi, FP

2015-03-01

Full Text Available -assisted optimization of the manganese redox states for enhanced capacity and capacity retention of LiAlxMn2-xO4 (x = 0 and 0.3) spinel materials Funeka P. Nkosi1,2, Charl J. Jafta2, Mesfin Kebede2, Lukas le Roux2, Mkhulu K. Mathe2, and Kenneth I. Ozoemena,1... polypropylene-based membrane separator soaked in non-aqueous electrolyte. A 1 M LiPF6 in EC/DC/DMC in 1:1:1 volume ratio solution was used as the electrolyte. LiPF6 in EC-DMC-DEC has increased ion mobility and high ionic conductivity compared to a commercial...

The Effects of Computer-Assisted Instruction on the Achievement, Attitudes and Retention of Fourth Grade Mathematics Students in North Cyprus

Science.gov (United States)

Pilli, Olga; Aksu, Meral

2013-01-01

The purpose of this study was to examine the effects of the educational software "Frizbi Mathematics 4" on 4th grade student's mathematics achievement, retention, attitudes toward mathematics and attitude toward computer assisted learning. Two groups (experimental and control) of students from the state primary school in Gazimagusa,…

Water Retention Capacity of Argillite from the VE Test - Phase II at Mont Terri: Effect of Ventilation

International Nuclear Information System (INIS)

Villar, M. V.; Fernandez, A. M.; Melon, A. M.

2009-01-01

The VE (ventilation) test carried out at the Mont Terri underground laboratory in Switzerland intended to evaluate in situ the behaviour of a consolidated clay formation when subjected to alternate periods of flow of wet and dry air during several months. For that, a 10-m gallery was excavated in the Opalinus Clay formation and carefully instrumented. Before and after a second ventilation phase boreholes were drilled. Samples were taken from the drill cores and were analysed from mineralogical and geochemical points of view. Also, the retention curves of these samples were determined in the laboratory following drying paths performed under free volume conditions at 20 degree centigrade, what is the content of this report. Although there are not large differences in the WRC of samples taken from different boreholes, at different distances from the gallery wall or before or after ventilation, those samples taken near the gallery wall and after ventilation tend to show a higher water retention capacity. This has been correlated to the higher salinity of the pore water of these samples, what increases their osmotic suction. This effect is attenuated towards high suctions. (Author) 10 refs

Water Retention Capacity of Argillite from the VE Test - Phase II at Mont Terri: Effect of Ventilation

Energy Technology Data Exchange (ETDEWEB)

Villar, M. V.; Fernandez, A. M.; Melon, A. M.

2009-10-12

The VE (ventilation) test carried out at the Mont Terri underground laboratory in Switzerland intended to evaluate in situ the behaviour of a consolidated clay formation when subjected to alternate periods of flow of wet and dry air during several months. For that, a 10-m gallery was excavated in the Opalinus Clay formation and carefully instrumented. Before and after a second ventilation phase boreholes were drilled. Samples were taken from the drill cores and were analysed from mineralogical and geochemical points of view. Also, the retention curves of these samples were determined in the laboratory following drying paths performed under free volume conditions at 20 degree centigrade, what is the content of this report. Although there are not large differences in the WRC of samples taken from different boreholes, at different distances from the gallery wall or before or after ventilation, those samples taken near the gallery wall and after ventilation tend to show a higher water retention capacity. This has been correlated to the higher salinity of the pore water of these samples, what increases their osmotic suction. This effect is attenuated towards high suctions. (Author) 10 refs.

Assessing effects of aerobic and anaerobic conditions on phosphorus sorption and retention capacity of water treatment residuals.

Science.gov (United States)

Oliver, Ian W; Grant, Cameron D; Murray, Robert S

2011-03-01

Water treatment residuals (WTRs) are the by-products of drinking water clarification processes, whereby chemical flocculants such as alum or ferric chloride are added to raw water to remove suspended clay particles, organic matter and other materials and impurities. Previous studies have identified a strong phosphorus (P) fixing capacity of WTRs which has led to experimentation with their use as P-sorbing materials for controlling P discharges from agricultural and forestry land. However, the P-fixing capacity of WTRs and its capacity to retain sorbed P under anaerobic conditions have yet to be fully demonstrated, which is an issue that must be addressed for WTR field applications. This study therefore examined the capacity of WTRs to retain sorbed P and sorb further additional P from aqueous solution under both aerobic and anaerobic conditions. An innovative, low cost apparatus was constructed and successfully used to rapidly establish anoxic conditions in anaerobic treatments. The results showed that even in treatments with initial solution P concentrations set at 100 mg l(-1), soluble reactive P concentrations rapidly fell to negligible levels (due to sorption by WTRs), while total P (i.e. dissolved + particulate and colloidal P) was less than 3 mg l(-1). This equated to an added P retention rate of >98% regardless of anaerobic or aerobic status, indicating that WTRs are able to sorb and retain P in both aerobic and anaerobic conditions. Copyright © 2010 Elsevier Ltd. All rights reserved.

A strategic approach to employee retention.

Science.gov (United States)

Gering, John; Conner, John

2002-11-01

A sound retention strategy should incorporate a business plan, a value proposition, progress measures, and management influences. The business plan will indicate whether a healthcare organization will achieve a return on investment for its effort. A value proposition will showcase an organization's strengths and differentiate it from its competitors. Measuring progress toward meeting retention goals at regular intervals will help keep an organization on track. The best managers require accountability, rewarding employees for their successes and taking corrective action as necessary. Retention rate targets must be at a level that will achieve a competitive advantage in the served market.

The water retention of a granite rock fragments in High Tatras stony soils

OpenAIRE

Novák, Viliam; Šurda, Peter

2010-01-01

The water retention capacity of coarse rock fragments is usually considered negligible. But the presence of rock fragments in a soil can play an important role in both water holding capacity and in hydraulic conductivity as well. This paper presents results of maximum water holding capacity measured in coarse rock fragments in the soil classified as cobbly sandy loam sampled at High Tatra mountains. It is shown, that those coarse rock (granite) fragments have the maximum retention capacity up...

Bayesian modeling of the assimilative capacity component of nutrient total maximum daily loads

Science.gov (United States)

Faulkner, B. R.

2008-08-01

Implementing stream restoration techniques and best management practices to reduce nonpoint source nutrients implies enhancement of the assimilative capacity for the stream system. In this paper, a Bayesian method for evaluating this component of a total maximum daily load (TMDL) load capacity is developed and applied. The joint distribution of nutrient retention metrics from a literature review of 495 measurements was used for Monte Carlo sampling with a process transfer function for nutrient attenuation. Using the resulting histograms of nutrient retention, reference prior distributions were developed for sites in which some of the metrics contributing to the transfer function were measured. Contributing metrics for the prior include stream discharge, cross-sectional area, fraction of storage volume to free stream volume, denitrification rate constant, storage zone mass transfer rate, dispersion coefficient, and others. Confidence of compliance (CC) that any given level of nutrient retention has been achieved is also determined using this approach. The shape of the CC curve is dependent on the metrics measured and serves in part as a measure of the information provided by the metrics to predict nutrient retention. It is also a direct measurement, with a margin of safety, of the fraction of export load that can be reduced through changing retention metrics. For an impaired stream in western Oklahoma, a combination of prior information and measurement of nutrient attenuation was used to illustrate the proposed approach. This method may be considered for TMDL implementation.

Water retention in mushroom during sustainable processing

NARCIS (Netherlands)

Paudel, E.

2015-01-01

This thesis deals with the understanding of the water holding capacity of mushroom, in the context of a redesign of their industrial processing. For designing food process the retention of food quality is of the utmost importance. Water holding capacity is an important quality aspect of

Reading Achievement and In-Grade Retention Rate Differentials for Mexican-American and Black Students in Selected States of the Southwest.

Science.gov (United States)

Casavantes, Edward Joseph

Two sets of data from the U.S. Commission on Civil Rights' Mexican American Education Study were selected for analysis in the areas of (1) comparative reading achievement rates of Mexican Americans and black students; and (2) differential in-grade retention rates of Anglo, Mexican American, and black students. Two separate issues were examined.…

Growth, functional capacities and motivation for achievement and competitiveness in youth basketball: an interdisciplinary approach.

Science.gov (United States)

Carvalho, Humberto Moreira; Gonçalves, Carlos E; Collins, Dave; Paes, Roberto R

2018-04-01

The interaction of multiple influences on the path to sport success is not yet fully understood by sport scientists. In this study, we examined variation in body size, functional capacities and motivation for achievement, competitiveness and deliberate practice of youth basketball players associated with differences in biological maturity status, chronological age and years of training experience. Reflecting the importance of interactive effects, we examined the relationships between the psychological variables and functional capacities. Fifty-eight male basketball players aged 9.5 to 15.5 years were considered. Variables included chronological age, estimated age at peak height velocity, stature, body mass and sitting height by anthropometry; the Work and Family Orientation and Deliberate Practice Motivation Questionnaires were also used. Finally, the Line Drill test and Yo-Yo Intermittent Recovery level 1 (Yo-Yo IR1) tests were used as functional capacities indicators for basketball. Variance components models derived from series of multilevel linear regression models revealed a substantial variation by maturity status for body size, functional capacities indicators, mastery and will to excel. The influence of estimated maturity status on mastery and will to excel was independent of age and years of experience. In contrast, no relationships were observed between psychological variables and functional capacities indicators. We conclude that growth-related changes are relevant to understanding players´ motivations for achievement, competitiveness and deliberate practice. This should be of interest to those involved in the selection and development of youth basketball players.

Mentoring--a staff retention tool.

Science.gov (United States)

Kanaskie, Mary Louise

2006-01-01

Staff retention presents a common challenge for hospitals nationwide. Mentorship programs have been explored as one method of creating environments that promote staff retention. Successful achievement of nurse competencies identified in the Synergy Model for Patient Care can best be achieved in an environment that encourages and facilitates mentoring. Mentoring relationships in critical care provide the ongoing interactions, coaching, teaching, and role modeling to facilitate nurses' progression along this continuum. Mentoring relationships offer support and professional development for nurses at all levels within an organization as well as an optimistic outlook for the nursing profession.

Retention of bile salts in micellar electrokinetic chromatography: relation of capacity factor to octanol-water partition coefficient and critical micellar concentration.

Science.gov (United States)

Lucangioli, S E; Carducci, C N; Tripodi, V P; Kenndler, E

2001-12-25

The capacity factors of 16 anionic cholates (from six bile salts, including their glyco- and tauro-conjugates) were determined in a micellar electrokinetic chromatography (MEKC) system consisting of buffer, pH 7.5 (phosphate-boric acid; 20 mmol/l) with 50 mmol/l sodium dodecyl sulfate (SDS) as micelle former and 10% acetonitrile as organic modifier. The capacity factors of the fully dissociated, negatively charged analytes (ranging between 0.2 and 60) were calculated from their mobilities, with a reference background electrolyte (BGE) without SDS representing "free" solution. For comparison, the capacity factors were derived for a second reference BGE where the SDS concentration (5 mmol/l) is close to the critical micellar concentration (CMC). The capacity factors are compared with the logarithm of the octanol-water partition coefficient, log Pow, as measure for lipophilicity. Clear disagreement between these two parameters is found especially for epimeric cholates with the hydroxy group in position 7. In contrast, fair relation between the capacity factor of the analytes and their CMC is observed both depending strongly on the orientation of the OH groups, and tauro-conjugation as well. In this respect the retention behaviour of the bile salts in MEKC seems to reflect their role as detergents in living systems, and might serve as model parameter beyond lipophilicity.

EVALUATION OF WATER RETENTION CAPABILITY IN WETLANDS AT SMALL FOREST CATCHMENT

Directory of Open Access Journals (Sweden)

Daniel Liberacki

2015-07-01

Full Text Available The paper presents the results of researches carried out in the middle part of Pizza Zielonka forest complex. The aim was the evaluation of retention changes at wetlands and mid-forest ponds. The object of the study was the catchment of the Trojanka watercourse, considering from the origin to the cross-section of Zielonka Lake. The catchment is located in in the central part of the Wielkopolska region, approximatelly 20 km on the North-East of Poznań. The area of this forestall catchment is about 223 ha. In the paper an analysis of the results from three hydrological years was presented. The results of the years 1987 (wet year, 2003 (dry year and 2009 (medium year were analysed against meteorological conditions. Retention capacity in each wetlands, as well as the possibility of water retention in the Trojanka watercourse was calculated. The researches confirmed significant meteorological conditions influence the amount of retentioned water. The calculated capacity of retentioned water was 15 852 m3 considering the total area of wetland and swamp (8,58 ha and precipitation sum of 555 mm. 18% increase of water capacity was observed in wet year (1987 In this year the sum of precipitation was 100 mm higher than multiyear average sum. Meanwhile 62% decrease of water capacity was observed in dry year (2003, when the precipitation sum was 208 mm lower than multiyear average one.

Design of a 15N Molecular Unit to Achieve Long Retention of Hyperpolarized Spin State

Science.gov (United States)

Nonaka, Hiroshi; Hirano, Masashi; Imakura, Yuki; Takakusagi, Yoichi; Ichikawa, Kazuhiro; Sando, Shinsuke

2017-01-01

Nuclear hyperpolarization is a phenomenon that can be used to improve the sensitivity of magnetic resonance molecular sensors. However, such sensors typically suffer from short hyperpolarization lifetime. Herein we report that [15N, D14]trimethylphenylammonium (TMPA) has a remarkably long spin-lattice relaxation time (1128 s, 14.1 T, 30 °C, D2O) on its 15N nuclei and achieves a long retention of the hyperpolarized state. [15N, D14]TMPA-based hyperpolarized sensor for carboxylesterase allowed the highly sensitive analysis of enzymatic reaction by 15N NMR for over 40 min in phophate-buffered saline (H2O, pH 7.4, 37 °C).

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

Nitrate retention capacity of milldam-impacted legacy sediments and relict A horizon soils

Directory of Open Access Journals (Sweden)

J. N. Weitzman

2017-05-01

Full Text Available While eutrophication is often attributed to contemporary nutrient pollution, there is growing evidence that past practices, like the accumulation of legacy sediment behind historic milldams, are also important. Given their prevalence, there is a critical need to understand how N flows through, and is retained in, legacy sediments to improve predictions and management of N transport from uplands to streams in the context of climatic variability and land-use change. Our goal was to determine how nitrate (NO3− is cycled through the soil of a legacy-sediment-strewn stream before and after soil drying. We extracted 10.16 cm radius intact soil columns that extended 30 cm into each of the three significant soil horizons at Big Spring Run (BSR in Lancaster, Pennsylvania: surface legacy sediment characterized by a newly developing mineral A horizon soil, mid-layer legacy sediment consisting of mineral B horizon soil and a dark, organic-rich, buried relict A horizon soil. Columns were first preincubated at field capacity and then isotopically labeled nitrate (15NO3− was added and allowed to drain to estimate retention. The columns were then air-dried and subsequently rewet with N-free water and allowed to drain to quantify the drought-induced loss of 15NO3− from the different horizons. We found the highest initial 15N retention in the mid-layer legacy sediment (17 ± 4 % and buried relict A soil (14 ± 3 % horizons, with significantly lower retention in the surface legacy sediment (6 ± 1 % horizon. As expected, rewetting dry soil resulted in 15N losses in all horizons, with the greatest losses in the buried relict A horizon soil, followed by the mid-layer legacy sediment and surface legacy sediment horizons. The 15N remaining in the soil following the post-drought leaching was highest in the mid-layer legacy sediment, intermediate in the surface legacy sediment, and lowest in the buried relict A horizon soil. Fluctuations

Nitrate retention capacity of milldam-impacted legacy sediments and relict A horizon soils

Science.gov (United States)

Weitzman, Julie N.; Kaye, Jason P.

2017-05-01

While eutrophication is often attributed to contemporary nutrient pollution, there is growing evidence that past practices, like the accumulation of legacy sediment behind historic milldams, are also important. Given their prevalence, there is a critical need to understand how N flows through, and is retained in, legacy sediments to improve predictions and management of N transport from uplands to streams in the context of climatic variability and land-use change. Our goal was to determine how nitrate (NO3-) is cycled through the soil of a legacy-sediment-strewn stream before and after soil drying. We extracted 10.16 cm radius intact soil columns that extended 30 cm into each of the three significant soil horizons at Big Spring Run (BSR) in Lancaster, Pennsylvania: surface legacy sediment characterized by a newly developing mineral A horizon soil, mid-layer legacy sediment consisting of mineral B horizon soil and a dark, organic-rich, buried relict A horizon soil. Columns were first preincubated at field capacity and then isotopically labeled nitrate (15NO3-) was added and allowed to drain to estimate retention. The columns were then air-dried and subsequently rewet with N-free water and allowed to drain to quantify the drought-induced loss of 15NO3- from the different horizons. We found the highest initial 15N retention in the mid-layer legacy sediment (17 ± 4 %) and buried relict A soil (14 ± 3 %) horizons, with significantly lower retention in the surface legacy sediment (6 ± 1 %) horizon. As expected, rewetting dry soil resulted in 15N losses in all horizons, with the greatest losses in the buried relict A horizon soil, followed by the mid-layer legacy sediment and surface legacy sediment horizons. The 15N remaining in the soil following the post-drought leaching was highest in the mid-layer legacy sediment, intermediate in the surface legacy sediment, and lowest in the buried relict A horizon soil. Fluctuations in the water table at BSR which affect

effect of differentiated instructional strategies on students' retention

African Journals Online (AJOL)

PROF EKWUEME

show that retention ability was significantly higher in the experimental group ... Differentiated instruction, Lecture , Cognitive Achievement ,Retention ability, Geometry. ... thinking. Based on this knowledge, differentiated instruction applies an ...

Undergraduate Academic Achievement as an Indicator of Fleet Performance and Retention

National Research Council Canada - National Science Library

Gremillion, John

1998-01-01

...) and retention in the Navy. Understanding the relationship between college academic performance and job performance is important because of the organizational and cultural emphasis placed on academic grades...

Influence of cellulose ether particle size on water retention of freshly-mixed mortars

OpenAIRE

Patural , Laetitia; Govin , Alexandre; Grosseau , Philippe; Ruot , Bertrand; Deves , Olivier

2009-01-01

International audience; Cellulose ethers are polymers frequently introduced into mortar formulations in order to improve water retention capacity and workability of the freshly-mixed materials. Physico-chemical parameters of these admixtures (molecular weight, granulometry, substitution degrees, etc) seem to have a strong influence on mortar water retention capacity. In this paper, the influence of cellulose ether particle size was studied. Two behaviors were highlighted regarding the particl...

Predicting the scanning branches of hysteretic soil water-retention capacity with use of the method of mathematical modeling

Science.gov (United States)

Terleev, V.; Ginevsky, R.; Lazarev, V.; Nikonorov, A.; Togo, I.; Topaj, A.; Moiseev, K.; Abakumov, E.; Melnichuk, A.; Dunaieva, I.

2017-10-01

A mathematical model of the hysteresis of the water-retention capacity of the soil is proposed. The parameters of the model are interpreted within the framework of physical concepts of the structure and capillary properties of soil pores. On the basis of the model, a computer program with an interface that allows for dialogue with the user is developed. The program has some of options: visualization of experimental data; identification of the model parameters with use of measured data by means of an optimizing algorithm; graphical presentation of the hysteresis loop with application of the assigned parameters. Using the program, computational experiments were carried out, which consisted in verifying the identifiability of the model parameters from data on the main branches, and also in testing the ability to predict the scanning branches of the hysteresis loop. For the experiments, literature data on two sandy soils were used. The absence of an “artificial pump effect” is proved. A sufficiently high accuracy of the prediction of the scanning branches of the hysteresis loop has been achieved in comparison with the three models of the precursors. The practical importance of the proposed model and computer program, which is developed on its basis, is to ensure the calculation of precision irrigation rates. The application of such rates in irrigation farming will help to prevent excess moisture from flowing beyond the root layer of the soil and, thus, minimize the unproductive loss of irrigation water and agrochemicals, as well as reduce the risk of groundwater contamination and natural water eutrophication.

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.

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.

The Effect of Teaching Activities Done by Using Activity Based Posters on the Students' Academic Achievements, Retention Levels in Their Learning

Science.gov (United States)

Coskun, Ismail; Eker, Cevat

2018-01-01

The aim of the study is to investigate whether the activity based posters have an effect of on the ninth class students' academic achievements and the retention levels in their learning. The research was carried out with 60 students at one of the state schools in The Central Anatolia Region of Turkey in 2015-2016 academic year.…

Thermal effect on water retention curve of bentonite: experiment and thermodynamic modeling

International Nuclear Information System (INIS)

Qin Bing; Chen Zhenghai; Sun Faxin; Liu Yuemiao; Wang Ju

2012-01-01

The thermal effects on water retention curve of GMZ bentonite were investigated experimentally and theoretically. Water retention tests were conducted on GMZ bentonite at five temperatures ranging from 20℃ to 100℃. Test results showed that the water retention capacity and the hysteresis of the water retention curve decreased with increasing temperature, and that the water retention curves at different temperatures were almost parallel to each other. Based on the thermodynamics of sorption, a model was established to describe the temperature influence on the water retention curve. The model was validated by comparing the model predictions and the test results. (authors)

An investigation of the leaf retention capacity, efficiency and mechanism for atmospheric particulate matter of five greening tree species in Beijing, China.

Science.gov (United States)

Liu, Jinqiang; Cao, Zhiguo; Zou, Songyan; Liu, Huanhuan; Hai, Xiao; Wang, Shihua; Duan, Jie; Xi, Benye; Yan, Guangxuan; Zhang, Shaowei; Jia, Zhongkui

2018-03-01

Urban trees have the potential to reduce air pollution, but the retention capacity and efficiency of different tree species for atmospheric particulate matter (PM) accumulation and the underlying mechanism hasn't been well understood. To select tree species with high air purification abilities, the supplementing ultrasonic cleaning (UC) procedure was first introduced into the conventional leaf cleaning methods [single water cleaning (WC) or plus brush cleaning (BC)] for eluting the leaf-retained PM. Further updates to the methodology were applied to investigate the retention capacity, efficiency, and mechanism for PM of five typical greening tree species in Beijing, China. Meanwhile, the particle size distribution of PM on the leaves, the PM retention efficiencies of easily removable (ERP), difficult-to-remove (DRP) and totally removable (TRP) particles on the leaf (AE leaf ), and the individual tree scales were estimated. The experimental leaf samples were collected from trees with similar sizes 4 (SDR) and 14days (LDR) after rainfall. When the leaves were cleaned by WC+BC, there was, on average, 29%-46% of the PM remaining on the leaves of different species, which could be removed almost completely if UC was supplemented. From SDR to LDR, the mass of the leaf-retained PM increased greatly, and the particle size distribution changed markedly for all species except for Sophorajaponica. Pinus tabuliformis retains particles with the largest average diameter (34.2μm), followed by Ginkgo biloba (20.5μm), Sabina chinensis (16.4μm), Salix babylonica (16.0μm), and S. japonica (13.1μm). S. japonica and S. chinensis had the highest AE leaf to retain the TRP and ERP of both PM 1 and PM 1-2.5 , respectively. Conversely, S. babylonica and P. tabuliformis could retain both TRP and ERP of PM 2.5-5 and PM 5-10 , and PM >10 and TSP with the highest AE leaf , respectively. In conclusion, our results could be useful in selecting greening tree species with high air purification

Oil sorption and retention capacities of thermally-bonded hybrid nonwovens prepared from cotton, kapok, milkweed and polypropylene fibers.

Science.gov (United States)

Thilagavathi, G; Praba Karan, C; Das, Dipayan

2018-08-01

This work reports on a series of thermally-bonded, hybrid and oil-sorbent nonwovens developed from binary and tertiary mixing of cotton, kapok, and three varieties of milkweed fibers (Asclepias Syriaca, Calotropis Procera and Calotropis Gigantea) and polypropylene fibers. The physical and chemical properties of the fibers were investigated to examine their oleophilic character. It was observed that all the fiber surfaces were covered with natural wax. Further, kapok and milkweed fibers were found to have less cell wall thickness and high void ratio. Oil sorption and retention characteristics of these fibers were studied in loose fibrous form as well as in structured assembly form (thermally-bonded nonwovens) using high density oil and diesel oil. The effects of fiber diameter, fiber cross-sectional shape, fiber surface area and porosity on the oil sorption behavior were discussed. An excellent and a selective oil sorption behavior of milkweed fibers (Calotropis Procera and Calotropis Gigantea) blended with cotton and polypropylene fibers were observed. The maximum oil sorption capacity of the developed thermal bonded nonwoven was 40.16 g/g for high density (HD) oil and 23.00 g/g for diesel oil. Further, a high porosity combined with high surface area played a major role in deciding the oil sorption and retention characteristics. Copyright © 2018 Elsevier Ltd. All rights reserved.

Neutral particle retention in the JET MK I divertor

International Nuclear Information System (INIS)

Ehrenberg, J.K.; Campbell, D.J.; Harbour, P.J.; Horton, L.D.; Loarte, A.; McCormick, G.K.; Monk, R.D.; Saibene, G.R.; Simonini, R.; Taroni, A.; Stamp, M.F.

1997-01-01

Retention of neutral deuterium and nitrogen in the JET MK I divertor has been investigated. Results show that ohmic plasma detachment reduces deuterium retention, that the magnetic divertor configuration has some influence on the achievable deuterium retention, and that nitrogen in nitrogen-seeded steady state detached H-mode discharges accumulates in the divertor. (orig.)

The Implementation of Knowledge Strategy-Based Entrepreneurial Capacity to Achieve Sustainable Competitive Advantage

OpenAIRE

Widodo

2013-01-01

This study aims to develop a model of knowledge strategy-based entrepreneurial capacity to achieve sustainable competitive advantage of rurol banking in Central Java province. The sampling method is ‘‘Purposive sampling’’ by considering the characteristics of the population items, namely: operational experience for at least 5 years and representatives of each area of rurol banking in Semarang, Surakarta and Purwokerto. Then, the sample size is 150 of 251 (59.7%) of top managers of rurol bank...

Effects of Academic Mindsets on College Students' Achievement and Retention

Science.gov (United States)

Han, Cheon-woo; Farruggia, Susan P.; Moss, Thomas P.

2017-01-01

Noncognitive factors, such as academic self-efficacy, motivation, and sense of belonging, predict college students' academic performance and retention. It is unclear if varying profiles of academic mindset are differentially associated with student success. We examined first-year college students' academic mindsets (perceived academic…

Achieving successful evidence-based practice implementation in juvenile justice: The importance of diagnostic and evaluative capacity.

Science.gov (United States)

Walker, Sarah Cusworth; Bumbarger, Brian K; Phillippi, Stephen W

2015-10-01

Evidence-based programs (EBPs) are an increasingly visible aspect of the treatment landscape in juvenile justice. Research demonstrates that such programs yield positive returns on investment and are replacing more expensive, less effective options. However, programs are unlikely to produce expected benefits when they are not well-matched to community needs, not sustained and do not reach sufficient reach and scale. We argue that achieving these benchmarks for successful implementation will require states and county governments to invest in data-driven decision infrastructure in order to respond in a rigorous and flexible way to shifting political and funding climates. We conceptualize this infrastructure as diagnostic capacity and evaluative capacity: Diagnostic capacity is defined as the process of selecting appropriate programing and evaluative capacity is defined as the ability to monitor and evaluate progress. Policy analyses of Washington State, Pennsylvania and Louisiana's program implementation successes are used to illustrate the benefits of diagnostic and evaluate capacity as a critical element of EBP implementation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Retenção de metais pesados em micélio de fungos micorrízicos arbusculares Retention of heavy metals by arbuscular mycorrhizal fungi mycelium

Directory of Open Access Journals (Sweden)

Lucélia Cabral

2010-01-01

Full Text Available This work evaluated the kinetics as well as the retention capacity of Cu, Zn, Cd, and Pb by arbuscular mycorrhizal fungi (AMF mycelium. The metal retention is a fast process with Cu being retained 3, 30, and 60 times faster than Zn, Cd, and Pb, respectively. Metal retention capacity varied amongst the different tested AMF species and decreased in the following order: Cu>Zn>>Cd>Pb. The Glomus clarum mycelium showed the highest retention capacity for Cu, Cd and Pb, whereas Zn was mostly retained by Gigaspora gigantea mycelium. The simultaneous application of all tested metals in solution decreased Cu and Zn retention by AMF mycelium. The high retention capacity of Cu and Zn by mycelium of G. clarum and G. gigantea suggests a promising use of these isolates in phytoremediation.

Seasonal variations of nitrogen and phosphorus retention in an agricultural drainage river in East China.

Science.gov (United States)

Chen, Dingjiang; Lu, Jun; Wang, Hailong; Shen, Yena; Kimberley, Mark O

2010-02-01

Riverine retention decreases loads of nitrogen (N) and phosphorus (P) in running water. It is an important process in nutrient cycling in watersheds. However, temporal riverine nutrient retention capacity varies due to changes in hydrological, ecological, and nutrient inputs into the watershed. Quantitative information of seasonal riverine N and P retention is critical for developing strategies to combat diffuse source pollution and eutrophication in riverine and coastal systems. This study examined seasonal variation of riverine total N (TN) and total P (TP) retention in the ChangLe River, an agricultural drainage river in east China. Water quality, hydrological parameters, and hydrophyte coverage were monitored along the ChangLe River monthly during 2004-2006. Nutrient export loads (including chemical fertilizer, livestock, and domestic sources) entering the river from the catchment area were computed using an export coefficient model based on estimated nutrient sources. Riverine TN and TP retention loads (RNRL and RPRL) were estimated using mass balance calculations. Temporal variations in riverine nutrient retention were analyzed statistically. Estimated annual riverine retention loads ranged from 1,538 to 2,127 t year(-1) for RNRL and from 79.4 to 90.4 t year(-1) for RPRL. Monthly retention loads varied from 6.4 to 300.8 t month(-1) for RNRL and from 1.4 to 15.3 t month(-1) for RPRL. Both RNRL and RPRL increased with river flow, water temperature, hydrophyte coverage, monthly sunshine hours, and total TN and TP inputs. Dissolved oxygen concentration and the pH level of the river water decreased with RNRL and RPRL. Riverine nutrient retention ratios (retention as a percentage of total input) were only related to hydrophyte coverage and monthly sunshine hours. Monthly variations in RNRL and RPRL were functions of TN and TP loads. Riverine nutrient retention capacity varied with environmental conditions. Annual RNRL and RPRL accounted for 30.3-48.3% and 52

A Simple Approach for Demonstrating Soil Water Retention and Field Capacity

Science.gov (United States)

Howard, A.; Heitman, J. L.; Bowman, D.

2010-01-01

It is difficult to demonstrate the soil water retention relationship and related concepts because the specialized equipment required for performing these measurements is unavailable in most classrooms. This article outlines a low-cost, easily visualized method by which these concepts can be demonstrated in most any classroom. Columns (62.5 cm…

Investigation of Organizational Factors for Achieving Nurse Retention: Literature Review

OpenAIRE

Sherestha Joshi , Archana; Nanba, Mineko

2015-01-01

Aim：In order to identify the organizational factors which influence leaving intention of nurses, this study aims to review literature and prior research from two major perspectives 1） job satisfaction and 2） organizational commitment.Review method: Literature review of articles which focus on relationships between various factors and employee retention. A special emphasis is given on employees’ behavior in health sector. A literature search was undertaken using two major healthcare related da...

The Effect of Computer Assisted Mind Mapping on Students’ Academic Achievement, Attitudes and Retention in Science and Technology Course

Directory of Open Access Journals (Sweden)

Mehmet Nuri GÖMLEKSİZ

2013-12-01

Full Text Available This study aims at determining the effects of computer assisted mind mapping (CAMM technique on students’ academic achievement, attitudes and retention in Science and Technology course. Mixed-method research design which included both quantitative and qualitative methods was used in the study. Pretest-posttest control group experimental design, interview and observation techniques were used. The study included one experimental (N:36 one control group (N:32. The study was conducted on seventh grade students at an elementary school in 2011-2012 academic year. While experimental group used CAMM technique, control group used traditional method. The achievement test, administered as a pre-, post- and delayed post-test, included 34 questions. The mean difficulty of the test was calculated to be .54 and KR-20 reliability coefficient was measured to be .73. To determine students' attitudes towards Science and Technology course, a 20-item five-point Likert-style attitude scale (α: .89 developed by Akınoğlu (2001 was used. The results revealed that CAMM technique had a positive effect on students’ achievement and attitudes towards learning science and technology

The Effects of Head Start on Children's Kindergarten Retention, Reading and Math Achievement in Fall Kindergarten--An Application of Propensity Score Method and Sensitivity Analysis

Science.gov (United States)

Dong, Nianbo

2009-01-01

Using data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 (ECLS-K), this paper applied optimal propensity score matching method to evaluate the effects of Head Start on children's kindergarten retention, reading and math achievement in fall kindergarten comparing with center-based care. Both parametric and nonparametric…

The Impact of Educational Games-Based iPad Applications on the Development of Social Studies Achievement and Learning Retention among Sixth Grade Students in Jeddah

Science.gov (United States)

Najmuldeen, Hanan A.

2017-01-01

The present study aims to evaluate the impact of educational games-based iPad applications on the development of social studies achievement and learning retention. Sample consisted of (48) sixth grade primary students in Jeddah. The author adopted Quasi-experimental design of the experimental and control groups. She also provided the teacher a…

Estimation of water retention and availability in soils of Rio Grande do Sul

OpenAIRE

Reichert,José Miguel; Albuquerque,Jackson Adriano; Kaiser,Douglas Rodrigo; Reinert,Dalvan José; Urach,Felipe Lavarda; Carlesso,Reimar

2009-01-01

Dispersed information on water retention and availability in soils may be compiled in databases to generate pedotransfer functions. The objectives of this study were: to generate pedotransfer functions to estimate soil water retention based on easily measurable soil properties; to evaluate the efficiency of existing pedotransfer functions for different geographical regions for the estimation of water retention in soils of Rio Grande do Sul (RS); and to estimate plant-available water capacity ...

The effect of earthworm coprolites on the soil water retention curve

Science.gov (United States)

Smagin, A. V.; Prusak, A. V.

2008-06-01

The effect of earthworm coprolites on the water retention curves in soils of different geneses and textures was investigated by the method of equilibrium centrifuging. Coprolites sampled in the field were compared with the surrounding soil. The effect of earthworms on a soddy-podzolic light loamy soil (from Moscow oblast) was comprehensively analyzed in the course of a special model experiment in a laboratory. This experiment was necessary because it was difficult to separate the coprolites from the soil, in which additional coprolites could appear under natural conditions. In all the variants of the experiment, the differences between the water retention curves of the coprolites and the surrounding soil (or control substrates unaffected by earthworms) were statistically significant. The development of coprolites favored a considerable increase (up to 20 wt.% and more) of the soil water retention capacity upon equivalent water potentials within the range from 0 to -1000 kPa. In most cases, the soil water retention capacity increased within the entire range of the soil moisture contents. This could be explained by the fact that strongly swelling hygroscopic plant remains (detritus) were included into the coprolites and by the formation of a specific highly porous aggregate structure.

Effect of Retention in First Grade on Children’s Achievement Trajectories Over 4 Years: A Piecewise Growth Analysis Using Propensity Score Matching

OpenAIRE

Wu, Wei; West, Stephen G.; Hughes, Jan N.

2008-01-01

The authors investigated the relatively short-term and longer term effects of grade retention in 1st grade on the growth of mathematics and reading achievement over 4 years. The authors initially identified a large multiethnic sample (n = 784) of children who were below the median in literacy at school entrance. From this sample, the authors closely matched 1 retained with 1 promoted child (n = 97 pairs) on the basis of propensity scores constructed from 72 background variables and compared g...

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.

Adding Behavioural Science Capacity to Document Deterrents and ...

International Development Research Centre (IDRC) Digital Library (Canada)

... psychosocial barriers and motivators to participation and retention in HIV vaccine research ... -promoting government capacity to advocate, support ethical research, ... IWRA/IDRC webinar on climate change and adaptive water management.

Assessment of retention parameters of the fission products in the soil

International Nuclear Information System (INIS)

Endo, Laura Sakiko

1978-01-01

In many countries the discharge of radioactive liquid wastes into the ground is a common practice. The retention capacity presented by soils allows the discharge of bulky amounts of wastes in low and intermediate concentrations, within safety conditions. In addition, operations of ground disposal have advantages in economy and simplicity. However, the possibility of contamination of water resources is important in the site selection for such purpose. In this work, the I.E.A. soil behavior related to the retention capacity of cesium and strontium was studied. Distribution coefficients (Kd) were determined for both elements in function of its concentrations, p H and the presence of K + and Na + in the waste solutions. Soil analysis by X-ray diffraction showed the predominance Kaolinite argyle in this region. Soil parameters were also determined in laboratory conditions, such as permeability, porosity and density. The observed retention capacity for both elements was between 0,7 and 2,0 meg/100 of soil. Evaluation of ground water velocity and ions migration rates were carried out through the results obtained in laboratory measurements. It was also evaluated the amounts of 137 Cs and 90 Sr that if discharged into the ground would produce in the critical group a dose equal to the dose limit fixed by the norms. It was concluded that the maximum discharge amounts is limited by heat dissipation capacity of ground water table, and through a very conservative evaluation the total beta-gamma activity for long-lives radioisotopes presented a value of 3,6 X 10 6 Ci/y. (author)

Brain oscillatory substrates of visual short-term memory capacity.

Science.gov (United States)

Sauseng, Paul; Klimesch, Wolfgang; Heise, Kirstin F; Gruber, Walter R; Holz, Elisa; Karim, Ahmed A; Glennon, Mark; Gerloff, Christian; Birbaumer, Niels; Hummel, Friedhelm C

2009-11-17

The amount of information that can be stored in visual short-term memory is strictly limited to about four items. Therefore, memory capacity relies not only on the successful retention of relevant information but also on efficient suppression of distracting information, visual attention, and executive functions. However, completely separable neural signatures for these memory capacity-limiting factors remain to be identified. Because of its functional diversity, oscillatory brain activity may offer a utile solution. In the present study, we show that capacity-determining mechanisms, namely retention of relevant information and suppression of distracting information, are based on neural substrates independent of each other: the successful maintenance of relevant material in short-term memory is associated with cross-frequency phase synchronization between theta (rhythmical neural activity around 5 Hz) and gamma (> 50 Hz) oscillations at posterior parietal recording sites. On the other hand, electroencephalographic alpha activity (around 10 Hz) predicts memory capacity based on efficient suppression of irrelevant information in short-term memory. Moreover, repetitive transcranial magnetic stimulation at alpha frequency can modulate short-term memory capacity by influencing the ability to suppress distracting information. Taken together, the current study provides evidence for a double dissociation of brain oscillatory correlates of visual short-term memory capacity.

Enhancing Academic Achievement and Retention in Senior Secondary School Chemistry through Discussion and Lecture Methods: A Case Study of Some Selected Secondary Schools in Gboko, Benue State, Nigeria

Science.gov (United States)

Omwirhiren, Efe M.

2015-01-01

The present study was initiated to determine how academic achievement and retention in chemistry is enhanced using the two instructional methods among SSII students and ascertained the differential performance of male and female students in chemistry with a view of improving student performance in chemistry. The study adopted a non-equivalent…

Improving Reversible Capacities of High-Surface Lithium Insertion Materials – The Case of Amorphous TiO2

International Nuclear Information System (INIS)

Ganapathy, Swapna; Basak, Shibabrata; Lefering, Anton; Rogers, Edith; Zandbergen, Henny W.; Wagemaker, Marnix

2014-01-01

Chemisorbed water and solvent molecules and their reactivity with components from the electrolyte in high-surface nano-structured electrodes remains a contributing factor toward capacity diminishment on cycling in lithium ion batteries due to the limit in maximum annealing temperature. Here, we report a marked improvement in the capacity retention of amorphous TiO 2 by the choice of preparation solvent, control of annealing temperature, and the presence of surface functional groups. Careful heating of the amorphous TiO 2 sample prepared in acetone under vacuum lead to complete removal of all molecular solvent and an improved capacity retention of 220 mAh/g over 50 cycles at a C/10 rate. Amorphous TiO 2 when prepared in ethanol and heated under vacuum showed an even better capacity retention of 240 mAh/g. From Fourier transform infra-red spectroscopy and electron energy loss spectroscopy measurements, the improved capacity is attributed to the complete removal of ethanol and the presence of very small fractions of residual functional groups coordinated to oxygen-deficient surface titanium sites. These displace the more reactive chemisorbed hydroxyl groups, limiting reaction with components from the electrolyte and possibly enhancing the integrity of the solid electrolyte interface. The present research provides a facile strategy to improve the capacity retention of nano-structured electrode materials.

Estimating water retention curves for sandy soils at the Doñana National Park, SW Spain

Science.gov (United States)

The determination of soil water retention curves (SWRC) in the laboratory is a slow and tedious task, which is especially challenging for sandy soils due to their low water retention capacity and large water content changes for small pressure head differences. Due to spatial variability within larg...

Synthesis and characterization of advanced high capacity cathode active nanomaterials with three integrated spinel-layered phases for Li-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Bulut, Emrah, E-mail: ebulut@sakarya.edu.tr [Department of Chemistry, Sakarya University, 54187 Serdivan, Sakarya (Turkey); Can, Mustafa, E-mail: mstfacan@gmail.com [Vocational School of Arifiye, Sakarya University, 54580 Arifiye, Sakarya (Turkey); Özacar, Mahmut, E-mail: nmozacart@hotmail.com [Department of Chemistry, Sakarya University, 54187 Serdivan, Sakarya (Turkey); Akbulut, Hatem, E-mail: akbulut@Sakarya.edu.tr [Department of Metallurgical and Materials Engineering, Sakarya University, 54187 Serdivan, Sakarya (Turkey)

2016-06-15

Mesoporous cathode active materials that included undoped and separated Cu{sup 2+} and Co{sup 3+} doped spinels were prepared. The “doped spinel-Layered-Li-rich spinel” composite nanoparticles within the three integrated phased (LiM{sub 0,02}Mn{sub 1,98}O{sub 4}–Li{sub 2}MnO{sub 3}–Li{sub 1,27}Mn{sub 1,73}O{sub 4}; where M is Cu{sup 2+} and Co{sup 3+}) were synthesized by a microwave assisted hydrothermal synthesis. These materials were investigated with X-Ray powder Diffraction spectroscopy (XRD), Scanning Electron Microscopy (SEM and FE-SEM), High Resolution Transmission Electron Microscopy (HR-TEM), galvanostatic cycling at 0.1C and 0.5C rates, Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS). The effects of the calcination temperature and the partial substitution of Mn{sup 3+} in the spinel by Cu{sup 2+} and Co{sup 3+}, and onto the spinel structure were investigated with XRD. The lattice parameters of the spinel structured compounds were calculated from the XRD data using the Williamson-Hall equation. However, the morphological changes, which depended on the calcination temperature, were examined by SEM, FE-SEM and HRTEM. Furthermore, the two other phases which were different from LiM{sub 0,02}Mn{sub 1,98}O{sub 4} had a great impact on the electrochemical performance over the potential range of the 3–5 V. At the 0.1C rate, the first discharge capacities of undoped and Cu{sup 2+}, Co{sup 3+} doped materials were 577, 285, 560 mAh/g respectively. After 50 cycles at 0.5C rate, we achieved 96.2%; 52.5%; 95.4% capacity retention for the undoped and Cu{sup 2+}, Co{sup 3+} doped materials respectively. - Highlights: • Mesoporous cathode active nanomaterials with three integrated phase were synthesized. • The materials were characterized structurally by XRD, FE-SEM, HR-TEM. • Integrated phases provide an additional 400 mAh/g discharge capacity at low rate. • Higher specific capacities than literature values were achieved at 0

The Impact of Early Grade Retention on the Academic Achievement and Self-Esteem of Seventh and Eighth Grade Students.

Science.gov (United States)

Setencich, Jill

Retention has been the answer to the problem of what to do with students who are unprepared for the academic and social demands of the next grade. Studies contend that children view retention as punishment and experience emotions such as fear, anger, and sadness when not promoted. Retention or nonpromotion can be defined as the practice of…

Capacity Bounds and High-SNR Capacity of MIMO Intensity-Modulation Optical Channels

KAUST Repository

Chaaban, Anas

2018-02-19

The capacity of the intensity modulation direct detection multiple-input multiple-output channel is studied. Therein, the nonnegativity constraint of the transmit signal limits the applicability of classical schemes, including precoding. Thus, new ways are required for deriving capacity bounds for this channel. To this end, capacity lower bounds are developed in this paper by deriving the achievable rates of two precodingfree schemes: Channel inversion and QR decomposition. The achievable rate of a DC-offset SVD-based scheme is also derived as a benchmark. Then, capacity upper bounds are derived and compared against the lower bounds. As a result, the capacity at high signal-to-noise ratio (SNR) is characterized for the case where the number of transmit apertures is not larger than the number of receive apertures, and is shown to be achievable by the QR decomposition scheme. This is shown for a channel with average intensity or peak intensity constraints. Under both constraints, the high-SNR capacity is approximated within a small gap. Extensions to a channel with more transmit apertures than receive apertures are discussed, and capacity bounds for this case are derived.

Capacity Bounds and High-SNR Capacity of MIMO Intensity-Modulation Optical Channels

KAUST Repository

Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

2018-01-01

The capacity of the intensity modulation direct detection multiple-input multiple-output channel is studied. Therein, the nonnegativity constraint of the transmit signal limits the applicability of classical schemes, including precoding. Thus, new ways are required for deriving capacity bounds for this channel. To this end, capacity lower bounds are developed in this paper by deriving the achievable rates of two precodingfree schemes: Channel inversion and QR decomposition. The achievable rate of a DC-offset SVD-based scheme is also derived as a benchmark. Then, capacity upper bounds are derived and compared against the lower bounds. As a result, the capacity at high signal-to-noise ratio (SNR) is characterized for the case where the number of transmit apertures is not larger than the number of receive apertures, and is shown to be achievable by the QR decomposition scheme. This is shown for a channel with average intensity or peak intensity constraints. Under both constraints, the high-SNR capacity is approximated within a small gap. Extensions to a channel with more transmit apertures than receive apertures are discussed, and capacity bounds for this case are derived.

Method of valuation of water field capacity

International Nuclear Information System (INIS)

Dancette, C.; Maertens, C.

1973-01-01

A method allowing the obtention of an approximation of field capacity, with only the determination of water retention at pF=3, is described. In alluvial soils, the accuracy of this method appears sufficient to satisfy the current needs in agriculture problems [fr

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

NARCIS (Netherlands)

Illa, Xavi; de Malsche, Wim; Gardeniers, Johannes G.E.; Desmet, Gert; Romano-Rodriguez, Albert

2010-01-01

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

Improving Reversible Capacities of High-Surface Lithium Insertion Materials – The Case of Amorphous TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Ganapathy, Swapna [Fundamental Aspects of Materials and Energy, Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands); Basak, Shibabrata [Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Lefering, Anton; Rogers, Edith [Fundamental Aspects of Materials and Energy, Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands); Zandbergen, Henny W. [Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Wagemaker, Marnix, E-mail: m.wagemaker@tudelft.nl [Fundamental Aspects of Materials and Energy, Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands)

2014-11-28

Chemisorbed water and solvent molecules and their reactivity with components from the electrolyte in high-surface nano-structured electrodes remains a contributing factor toward capacity diminishment on cycling in lithium ion batteries due to the limit in maximum annealing temperature. Here, we report a marked improvement in the capacity retention of amorphous TiO{sub 2} by the choice of preparation solvent, control of annealing temperature, and the presence of surface functional groups. Careful heating of the amorphous TiO{sub 2} sample prepared in acetone under vacuum lead to complete removal of all molecular solvent and an improved capacity retention of 220 mAh/g over 50 cycles at a C/10 rate. Amorphous TiO{sub 2} when prepared in ethanol and heated under vacuum showed an even better capacity retention of 240 mAh/g. From Fourier transform infra-red spectroscopy and electron energy loss spectroscopy measurements, the improved capacity is attributed to the complete removal of ethanol and the presence of very small fractions of residual functional groups coordinated to oxygen-deficient surface titanium sites. These displace the more reactive chemisorbed hydroxyl groups, limiting reaction with components from the electrolyte and possibly enhancing the integrity of the solid electrolyte interface. The present research provides a facile strategy to improve the capacity retention of nano-structured electrode materials.

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.

Bacterial polyextremotolerant bioemulsifiers from arid soils improve water retention capacity and humidity uptake in sandy soil

KAUST Repository

Raddadi, Noura

2018-05-31

Water stress is a critical issue for plant growth in arid sandy soils. Here, we aimed to select bacteria producing polyextremotolerant surface-active compounds capable of improving water retention and humidity uptake in sandy soils.From Tunisian desert and saline systems, we selected eleven isolates able to highly emulsify different organic solvents. The bioemulsifying activities were stable with 30% NaCl, at 4 and 120 °C and in a pH range 4-12. Applications to a sandy soil of the partially purified surface-active compounds improved soil water retention up to 314.3% compared to untreated soil. Similarly, after 36 h of incubation, the humidity uptake rate of treated sandy soil was up to 607.7% higher than untreated controls.Overall, results revealed that polyextremotolerant bioemulsifiers of bacteria from arid and desert soils represent potential sources to develop new natural soil-wetting agents for improving water retention in arid soils.

Bacterial polyextremotolerant bioemulsifiers from arid soils improve water retention capacity and humidity uptake in sandy soil

KAUST Repository

Raddadi, Noura; Giacomucci, Lucia; Marasco, Ramona; Daffonchio, Daniele; Cherif, Ameur; Fava, Fabio

2018-01-01

Water stress is a critical issue for plant growth in arid sandy soils. Here, we aimed to select bacteria producing polyextremotolerant surface-active compounds capable of improving water retention and humidity uptake in sandy soils.From Tunisian desert and saline systems, we selected eleven isolates able to highly emulsify different organic solvents. The bioemulsifying activities were stable with 30% NaCl, at 4 and 120 °C and in a pH range 4-12. Applications to a sandy soil of the partially purified surface-active compounds improved soil water retention up to 314.3% compared to untreated soil. Similarly, after 36 h of incubation, the humidity uptake rate of treated sandy soil was up to 607.7% higher than untreated controls.Overall, results revealed that polyextremotolerant bioemulsifiers of bacteria from arid and desert soils represent potential sources to develop new natural soil-wetting agents for improving water retention in arid soils.

Bacterial polyextremotolerant bioemulsifiers from arid soils improve water retention capacity and humidity uptake in sandy soil.

Science.gov (United States)

Raddadi, Noura; Giacomucci, Lucia; Marasco, Ramona; Daffonchio, Daniele; Cherif, Ameur; Fava, Fabio

2018-05-31

Water stress is a critical issue for plant growth in arid sandy soils. Here, we aimed to select bacteria producing polyextremotolerant surface-active compounds capable of improving water retention and humidity uptake in sandy soils. From Tunisian desert and saline systems, we selected eleven isolates able to highly emulsify different organic solvents. The bioemulsifying activities were stable with 30% NaCl, at 4 and 120 °C and in a pH range 4-12. Applications to a sandy soil of the partially purified surface-active compounds improved soil water retention up to 314.3% compared to untreated soil. Similarly, after 36 h of incubation, the humidity uptake rate of treated sandy soil was up to 607.7% higher than untreated controls. Overall, results revealed that polyextremotolerant bioemulsifiers of bacteria from arid and desert soils represent potential sources to develop new natural soil-wetting agents for improving water retention in arid soils.

Carrying the past to the future: Distinct brain networks underlie individual differences in human spatial working memory capacity.

Science.gov (United States)

Liu, Siwei; Poh, Jia-Hou; Koh, Hui Li; Ng, Kwun Kei; Loke, Yng Miin; Lim, Joseph Kai Wei; Chong, Joanna Su Xian; Zhou, Juan

2018-08-01

Spatial working memory (SWM) relies on the interplay of anatomically separated and interconnected large-scale brain networks. EEG studies often observe load-associated sustained negative activity during SWM retention. Yet, whether and how such sustained negative activity in retention relates to network-specific functional activation/deactivation and relates to individual differences in SWM capacity remain to be elucidated. To cover these gaps, we recorded concurrent EEG-fMRI data in 70 healthy young adults during the Sternberg delayed-match-to-sample SWM task with three memory load levels. To a subset of participants (N = 28) that performed the task properly and had artefact-free fMRI and EEG data, we employed a novel temporo-spatial principal component analysis to derive load-dependent negative slow wave (NSW) from retention-related event-related potentials. The associations between NSW responses with SWM capacity were divergent in the higher (N = 14) and lower (N = 14) SWM capacity groups. Specifically, larger load-related increase in NSW amplitude was associated with greater SWM capacity for the higher capacity group but lower SWM capacity for the lower capacity group. Furthermore, for the higher capacity group, larger NSW amplitude was related to greater activation in bilateral parietal areas of the fronto-parietal network (FPN) and greater deactivation in medial frontal gyrus and posterior mid-cingulate cortex of the default mode network (DMN) during retention. In contrast, the lower capacity group did not show similar pattern. Instead, greater NSW was linked to higher deactivation in right posterior middle temporal gyrus. Our findings shed light on the possible differential EEG-informed neural network mechanism during memory maintenance underlying individual differences in SWM capacity. Copyright © 2018 Elsevier Inc. All rights reserved.

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

Study on soil-water retention curves for loess aerated zone

International Nuclear Information System (INIS)

Guo Zede; Cheng Jinru; Deng An; Masayuki Mukai; Hideo Kamiyama

2000-01-01

The author introduces the measuring method and results of soil-water retention curves of 46 samples taken from ground surface to water table of 28 m depth at CIRP's Field Test Site. The results indicate that the soil-water retention characteristics vary significantly with depth, and the loess-aerated zone at the site can be divided into five layers. From the results, unsaturated hydraulic parameters are deduced, such as conductivity, specific water capacity and equivalent pore diameter. The water velocity calculated from these parameters is satisfactorily consistent with that one obtained from 3 H tracing test carried out at the site

Carbon Dioxide Sealing Capacity: Textural or Compositional Controls?

Energy Technology Data Exchange (ETDEWEB)

Cranganu, Constantin; Soleymani, Hamidreza; Sadiqua, Soleymani; Watson, Kieva

2013-11-30

This research project is aiming to assess the carbon dioxide sealing capacity of most common seal-rocks, such as shales and non-fractured limestones, by analyzing the role of textural and compositional parameters of those rocks. We hypothesize that sealing capacity is controlled by textural and/or compositional pa-rameters of caprocks. In this research, we seek to evaluate the importance of textural and compositional parameters affecting the sealing capacity of caprocks. The conceptu-al framework involves two testable end-member hypotheses concerning the sealing ca-pacity of carbon dioxide reservoir caprocks. Better understanding of the elements controlling sealing quality will advance our knowledge regarding the sealing capacity of shales and carbonates. Due to relatively low permeability, shale and non-fractured carbonate units are considered relatively imper-meable formations which can retard reservoir fluid flow by forming high capillary pres-sure. Similarly, these unites can constitute reliable seals for carbon dioxide capture and sequestration purposes. This project is a part of the comprehensive project with the final aim of studying the caprock sealing properties and the relationship between microscopic and macroscopic characteristics of seal rocks in depleted gas fields of Oklahoma Pan-handle. Through this study we examined various seal rock characteristics to infer about their respective effects on sealing capacity in special case of replacing reservoir fluid with super critical carbon dioxide (scCO{sub 2}). To assess the effect of textural and compositional properties on scCO{sub 2} maximum reten-tion column height we collected 30 representative core samples in caprock formations in three counties (Cimarron, Texas, Beaver) in Oklahoma Panhandle. Core samples were collected from various seal formations (e.g., Cherokee, Keys, Morrowan) at different depths. We studied the compositional and textural properties of the core samples using several techniques

Evaluation and capacity building to improve precollege science and mathematics achievement in the US: 10 CFR, Part 605

Energy Technology Data Exchange (ETDEWEB)

1992-01-01

The National Center for Improving Science Education has undertaken activities to achieve evaluation goals for DOE's Precollege programs: develop means to determine program quality; develop means for determining the contribution of DOE precollege programs to both teacher enhancement and student achievement; provide evaluation designs and instruments and reports of program quality and impact; and strengthen both DOE's and the Labs' capacity to do both short- and long-term planning as well as deliver effective programs and evaluation. Appendices include evaluation/technical assistance report, profiling teacher research participation and teacher development programs, teacher surveys, impact assessment design, and teacher research participation programs anecdotes for 8 labs.

Data on effects of rotenone on calcium retention capacity, respiration and activities of respiratory chain complexes I and II in isolated rat brain mitochondria

Directory of Open Access Journals (Sweden)

Evelina Rekuviene

2017-08-01

Full Text Available The data presented in this article are related to the research article entitled “Rotenone decreases ischemia-induced injury by inhibiting mitochondrial permeability transition in mature brains” (Rekuviene et al., 2017 [1]. Data in this article present the direct effects of rotenone on calcium retention capacity (CRC in isolated normal cortex and cerebellum mitochondria, effects of rotenone intravenous infusion on leak and phosphorylating respiration rates of isolated cortex and cerebellum mitochondria, on activities of respiratory chain complexes I and II in freezed-thawed/sonicated cortex and cerebellum mitochondria after brain ischemia. In addition, detailed experimental procedures of isolation of brain mitochondria, measurements of CRC, respiration, activities of respiratory chain complexes and H2O2 generation in cortex and cerebellum mitochondria are described.

Influence of feedstock on the copper removal capacity of waste-derived biochars.

Science.gov (United States)

Arán, Diego; Antelo, Juan; Fiol, Sarah; Macías, Felipe

2016-07-01

Biochar samples were generated by low temperature pyrolysis of different types of waste. The physicochemical characteristics of the different types of biochar affected the copper retention capacity, by determining the main mechanism involved. The capacity of the biochar to retain copper present in solution depended on the size of the inorganic fraction and varied in the following order: rice biochar>chicken manure biochar>olive mill waste biochar>acacia biochar>eucalyptus biochar>corn cob biochar. The distribution of copper between the forms bound to solid biochar, dissolved organic matter and free organic matter in solution also depended on the starting material. However, the effect of pH on the adsorption capacity was independent of the nature of the starting material, and the copper retention of all types of biochar increased with pH. Copyright © 2016 Elsevier Ltd. All rights reserved.

Psychological career meta-capacities in relation to employees ...

African Journals Online (AJOL)

A canonical correlation analysis indicated a significant overall relationship between the psychological career meta-capacities and the retention- related dispositions. Structural equation modelling indicated a good fit of the data with the canonical correlation-derived measurement model. In the employment equity context, the ...

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.

Improving student retention in computer engineering technology

Science.gov (United States)

Pierozinski, Russell Ivan

The purpose of this research project was to improve student retention in the Computer Engineering Technology program at the Northern Alberta Institute of Technology by reducing the number of dropouts and increasing the graduation rate. This action research project utilized a mixed methods approach of a survey and face-to-face interviews. The participants were male and female, with a large majority ranging from 18 to 21 years of age. The research found that participants recognized their skills and capability, but their capacity to remain in the program was dependent on understanding and meeting the demanding pace and rigour of the program. The participants recognized that curriculum delivery along with instructor-student interaction had an impact on student retention. To be successful in the program, students required support in four domains: academic, learning management, career, and social.

Working Memory Capacity Limits Motor Learning When Implementing Multiple Instructions

Directory of Open Access Journals (Sweden)

Tim Buszard

2017-08-01

Full Text Available Although it is generally accepted that certain practice conditions can place large demands on working memory (WM when performing and learning a motor skill, the influence that WM capacity has on the acquisition of motor skills remains unsubstantiated. This study examined the role of WM capacity in a motor skill practice context that promoted WM involvement through the provision of explicit instructions. A cohort of 90 children aged 8 to 10 years were assessed on measures of WM capacity and attention. Children who scored in the lowest and highest thirds on the WM tasks were allocated to lower WM capacity (n = 24 and higher WM capacity (n = 24 groups, respectively. The remaining 42 participants did not participate in the motor task. The motor task required children to practice basketball shooting for 240 trials in blocks of 20 shots, with pre- and post-tests occurring before and after the intervention. A retention test was administered 1 week after the post-test. Prior to every practice block, children were provided with five explicit instructions that were specific to the technique of shooting a basketball. Results revealed that the higher WM capacity group displayed consistent improvements from pre- to post-test and through to the retention test, while the opposite effect occurred in the lower WM capacity group. This implies that the explicit instructions had a negative influence on learning by the lower WM capacity children. Results are discussed in relation to strategy selection for dealing with instructions and the role of attention control.

[Comparative study of retention of a Zn phosphate cement and 4-META].

Science.gov (United States)

Maroto Garcia, J

1990-12-01

The recent appearance, in the market of the supercements, suggest to us, news concepts of retention-adhesion, of our preparations, that they are going to put in to the mouth. Between his applications, we have the cementation of crowns, post or dowels, adhesive-prosthesis, and inlays. According to the manufactures, the long duration of the bond power, his great physiques properties, and his easy management, gives to this products a good conditions, to use in the mouth. The present report to prove in vitro, the retentive capacity on the dentine without treatment, and metal.

Herpes zoster infection: a rare cause of acute urinary retention.

Science.gov (United States)

Chan, Jonathan E; Kapoor, Anil

2003-06-01

Herpes zoster (HZ) infection has been reported as a rare cause of acute urinary retention. HZ infection involving sacral, thoracolumbar, and rarely high thoracic dermatomes is believed to occasionally cause motor and sensory neuropathy of the bladder. This is specifically achieved by the interruption of the detrusor reflex causing subsequent bladder atonia. As the course and management of this entity is quite benign, HZ should remain a diagnostic consideration in the management of urinary retention. We report a case of acute urinary retention of approximately 2.5 liters associated with HZ infection and review the proposed pathogenesis and therapeutic considerations in the management of this entity.

Occurrence of sweet refuse at disposal sites: rainwater retention capacity and potential breeding opportunities for Aedes aegypti.

Science.gov (United States)

Dieng, Hamady; Satho, Tomomitsu; Meli, Nur Khairatun Khadijah Binti; Abang, Fatimah; Nolasco-Hipolito, Cirilo; Hakim, Hafijah; Miake, Fumio; Zuharah, Wan Fatma; Kassim, Nur Faeza A; Ab Majid, Abdul Hafiz; Morales Vargas, Ronald E; Morales, Noppawan P; Noweg, Gabriel Tonga

2018-05-01

Nectar is the staple diet of adult mosquitoes in the wild, but its availability is inconsistent and can be affected by rainfall. In urban centers, Aedes vectors commonly use man-made containers as their major habitat; however, they can colonize any items replenished by rainfall. Garbage output has increased significantly in recent years, at a time when collection frequency is reducing. Such garbage usually includes organic components, some of which are sweet and can be fed upon by other animals or become can containers for rainwater. Despite evidence that Aedes larvae can thrive in containers comprised of organic waste material, which can be produced by rodents gnawing on fruits or vegetables, and that adults can survive on sweet waste fluids, the capacity of organic waste materials to accumulate rainwater and act as egg deposition sites has not been examined. It is also unknown for how long sweet extracts can sustain the life of adult vectors. Here, we investigated the abundance of sweet leftovers at garbage sites and the rainwater retention capacity of some organic materials through a field survey and laboratory bioassays. We also examined whether sweet waste fluids impact egg hatching success and longevity of Aedes aegypti. The results of this study indicated that sweet products with leftovers are highly prevalent in garbage. When exposed to rain, food items (BAFrc, banana fruit resembling container; and BSPrc, boiled sweet potato resembling container) and the packaging of sweet foods (SMIc, sweetened condensed milk can) retained water. When provided an opportunity to oviposit in cups containing BAF extract (BAFex), BSP extract (BSPex), and SMI extract (SMIex), eggs were deposited in all media. Egg maturation in the BAFex environment resulted in similar larval eclosion success to that resulting from embryo development in a water milieu. Adults maintained on sweet waste extracts had long lifespans, although shorter than that of their sugar solution (SUS

Relationships of flour solvent retention capacity, secondary structure and rheological properties with the cookie making characteristics of wheat cultivars.

Science.gov (United States)

Kaur, Amritpal; Singh, Narpinder; Kaur, Seeratpreet; Ahlawat, Arvind Kumar; Singh, Anju Mahendru

2014-09-01

The relationships of grain, flour solvent retention capacity (SRC) and dough rheological properties with the cookie making properties of wheat cultivars were evaluated. Cultivars with higher proportion of intermolecular-β-sheets+antiparallel β sheets and lower α-helix had greater gluten strength. The grain weight and diameter positively correlated with the proportion of fine particles and the cookie spread factor (SF) and negatively to the grain hardness (GH) and Na2CO3 SRC. The SF was higher in the flour with a higher amount of fine particle and with a lower Na2CO3 SRC and dough stability (DS). The breaking strength (BS) of cookies was positively correlated to lactic acid (LA) SRC, DS, peak time, sedimentation value (SV), G' and G″. Na2CO3 SRC and GH were strongly correlated. The gluten performance index showed a strong positive correlation with SV, DS, G' and G″. The water absorption had a significant positive correlation with sucrose SRC and LASRC. Cultivars with higher GH produced higher amount of coarse particles in flours that had higher Na2CO3 SRC and lower cookie SF. Copyright © 2014 Elsevier Ltd. All rights reserved.

Natural flood retention in mountain areas by forests and forest like short rotation coppices

Science.gov (United States)

Reinhardt-Imjela, Christian; Schulte, Achim; Hartwich, Jens

2017-04-01

Natural water retention is an important element of flood risk management in flood generating headwater areas in the low mountain ranges of Central Europe. In this context forests are of particular interest because of the high infiltration capacities of the soils and to increase water retention reforestation of agricultural land would be worthwhile. However competing claims for land use in intensely cultivated regions in Central Europe impede reforestation plans so the potential for a significant increase of natural water retention in forests is strongly limited. Nevertheless the development of innovative forms of land use and crop types opens new perspectives for a combination of agricultural land use with the water retention potential of forests. Recently the increasing demand for renewable energy resources leads to the cultivation of fast growing poplar and willow hybrids on agricultural land in short rotation coppices (SRC). Harvested in cycles of three to six years the wood from the plantations can be used as wood chips for heat and electricity production in specialized power plants. With short rotation plantations a crop type is established on arable land which is similar to forests so that an improvement of water retention can be expected. To what extend SRC may contribute to flood attenuation in headwater areas is investigated for the Chemnitzbach watershed (48 km2) in the Eastern Ore Mountains (Free State of Saxony, Germany), a low mountain range which is an important source of flood runoff in the Elbe basin. The study is based on a rainfall-runoff model of flood events using the conceptual modelling system NASIM. First results reveal a significant reduction of the flood peaks after the implementation of short rotation coppices. However the effect strongly depends on two factors. The first factor is the availability of areas for the plantations. For a substantial impact on the watershed scale large areas are required and with decreasing percentages of SRC

Effects of Digital Story on Academic Achievement, Learning Motivation and Retention among University Students

Science.gov (United States)

Aktas, Elif; Yurt, Serap Uzuner

2017-01-01

The aim of this study was to determine the effect of the learning environment where digital stories are used as a learning material on the motivation, academic success, retention, and students' opinions. The study was carried out with mixed method which is a combination of quantitative and qualitative research approach. The study was implemented…

Preparation and properties of a coated slow-release and water-retention biuret phosphoramide fertilizer with superabsorbent.

Science.gov (United States)

Jin, Shuping; Yue, Guoren; Feng, Lei; Han, Yuqi; Yu, Xinghai; Zhang, Zenghu

2011-01-12

In this investigation, a novel water-insoluble slow-release fertilizer, biuret polyphosphoramide (BPAM), was formulated and synthesized from urea, phosphoric acid (H(3)PO(4)), and ferric oxide (Fe(2)O(3)). The structure of BPAM was characterized by Fourier transform infrared (FTIR) spectroscopy. Subsequently, a coated slow-release BPAM fertilizer with superabsorbent was prepared by ionic cross-linked carboxymethylchitosan (the core), acrylic acid, acrylamide, and active carbon (the coating). The variable influences on the water absorbency were investigated and optimized. Component analysis results showed that the coated slow-release BPAM contained 5.66% nitrogen and 11.7% phosphorus. The property of water retention, the behavior of slow release of phosphorus, and the capacity of adsorption of cations were evaluated, and the results revealed that the product not only had good slow-release property and excellent water retention capacity but also higher adsorption capacities of cations in saline soil.

Achieving High-Energy-High-Power Density in a Flexible Quasi-Solid-State Sodium Ion Capacitor.

Science.gov (United States)

Li, Hongsen; Peng, Lele; Zhu, Yue; Zhang, Xiaogang; Yu, Guihua

2016-09-14

Simultaneous integration of high-energy output with high-power delivery is a major challenge for electrochemical energy storage systems, limiting dual fine attributes on a device. We introduce a quasi-solid-state sodium ion capacitor (NIC) based on a battery type urchin-like Na2Ti3O7 anode and a capacitor type peanut shell derived carbon cathode, using a sodium ion conducting gel polymer as electrolyte, achieving high-energy-high-power characteristics in solid state. Energy densities can reach 111.2 Wh kg(-1) at power density of 800 W kg(-1), and 33.2 Wh kg(-1) at power density of 11200 W kg(-1), which are among the best reported state-of-the-art NICs. The designed device also exhibits long-term cycling stability over 3000 cycles with capacity retention ∼86%. Furthermore, we demonstrate the assembly of a highly flexible quasi-solid-state NIC and it shows no obvious capacity loss under different bending conditions.

Working memory capacity and the spacing effect in cued recall.

Science.gov (United States)

Delaney, Peter F; Godbole, Namrata R; Holden, Latasha R; Chang, Yoojin

2018-07-01

Spacing repetitions typically improves memory (the spacing effect). In three cued recall experiments, we explored the relationship between working memory capacity and the spacing effect. People with higher working memory capacity are more accurate on memory tasks that require retrieval relative to people with lower working memory capacity. The experiments used different retention intervals and lags between repetitions, but were otherwise similar. Working memory capacity and spacing of repetitions both improved memory in most of conditions, but they did not interact, suggesting additive effects. The results are consistent with the ACT-R model's predictions, and with a study-phase recognition process underpinning the spacing effect in cued recall.

Enhancement of water retention by cross-linked carboxymethylcellulose through polystyrene grafting or γ irradiation

International Nuclear Information System (INIS)

Bhattacharjee, S.S.; Perlin, A.S.

1975-01-01

The absorbency and retention characteristics of crosslinked carboxymethylcellulose (CLCMC) with respect to water and saline can be substantially improved by two different treatments. One treatment involves γ-radioinduced grafting of polystyrene onto fibers of CLCMC. At a critical level of grafting (approximately 25 percent) the retentive capacity of the fibers is almost doubled. Particularly noteworthy is the sharp increase that follows an initial drop in retentivity. It is concluded the polystyrene becomes associated preferentially with residual ordered regions of the CLCMC macromolecule, through the localization of free radicals in these regions. A second means for enhancing the water and saline retention value of CLCMC, consists of subjecting the material to gamma irradiation from a 60 Co source. Dosages used have ranged from 1.0 to 4.8 megarads (MR), depending on the degree of substitution of the initial carboxymethylcellulose. (JGB)

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

Considerations concerning the strategy of corium retention in the reactor vessel

International Nuclear Information System (INIS)

2015-01-01

Third-generation nuclear reactors are characterised by consideration during design of core meltdown accidents. More specifically, dedicated measures or devices must be implemented to avoid basemat melt-through in the reactor building. These devices must have a high level of confidence. The strategy of corium retention in the reactor vessel, if supported by appropriate research and development, makes it possible to achieve this objective. IRSN works alone or in partnerships to address all the issues associated with in-vessel corium retention. This document describes the in-vessel corium retention strategy and its limitations, along with the research programs conducted by IRSN in this area

Cr(VI) retention and transport through Fe(III)-coated natural zeolite

Energy Technology Data Exchange (ETDEWEB)

Du, Gaoxiang [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Li, Zhaohui, E-mail: li@uwp.edu [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Libing [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Hanson, Renee; Leick, Samantha; Hoeppner, Nicole [Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Jiang, Wei-Teh [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

2012-06-30

Graphical abstract: Breakthrough curves of Cr(VI) from columns packed with raw zeolite (a) and Fe(III)-zeolite (b). The solid line in (b) is the HYDRUS-1D fit to the observed data with adsorption term only, while the dashed line in (b) includes a reduction term in the HYDRUS-1D fit. Highlights: Black-Right-Pointing-Pointer Zeolite modified with Fe(III) could be used for adsorption and retention of Cr(VI). Black-Right-Pointing-Pointer The Fe present on zeolite was in an amorphous Fe(OH){sub 3} form. Black-Right-Pointing-Pointer A Cr(VI) adsorption capacity of 82 mg/kg was found on Fe(III)-zeolite. Black-Right-Pointing-Pointer A Cr(VI) retardation factor of 3 or 5 was determined from column and batch studies. - Abstract: Cr(VI) is a group A chemical based on the weight of evidence of carcinogenicity. Its transport and retention in soils and groundwater have been studied extensively. Zeolite is a major component in deposits originated from volcanic ash and tuff after alteration. In this study, zeolite aggregates with the particle size of 1.4-2.4 mm were preloaded with Fe(III). The influence of present Fe(III) on Cr(VI) retention by and transport through zeolite was studied under batch and column experiments. The added Fe(III) resulted in an enhanced Cr(VI) retention by the zeolite with a capacity of 82 mg/kg. The Cr(VI) adsorption on Fe(III)-zeolite followed a pseudo-second order kinetically and the Freundlich adsorption isotherm thermodynamically. Fitting the column experimental data to HYDRUS-1D resulted in a retardation factor of 3 in comparison to 5 calculated from batch tests at an initial Cr(VI) concentration of 3 mg/L. The results from this study showed that enhanced adsorption and retention of Cr(VI) may happen in soils derived from volcanic ash and tuff that contains significant amounts of zeolite with extensive Fe(III) coating.

Assessment of nurse retention challenges and strategies in Lebanese hospitals: the perspective of nursing directors.

Science.gov (United States)

El-Jardali, Fadi; Merhi, Mirvat; Jamal, Diana; Dumit, Nuhad; Mouro, Gladys

2009-05-01

Assess nurse retention challenges and strategies as perceived by nursing directors in Lebanese hospitals. The Kampala Health Workforce Declaration stressed the importance of retaining an effective, responsive and equitably distributed health workforce, particularly nurses. Little is known about nurse retention challenges and strategies in Lebanon. Nursing directors of 76 hospitals participated and were sent a two-page survey on perceived retention challenges and hospital-based retention strategies. Retention challenges included unsatisfactory salary, unsuitable shifts and working hours, as well as better opportunities in other areas within or outside Lebanon. Retention strategies included implementing financial rewards and benefits, a salary scale, staff development, praise and improving work environment. Nursing directors did not address all perceived challenges in their strategies. To better manage the nursing workforce, nursing directors should regularly measure and monitor nurse turnover rates and also their causes and predictors. Nursing directors should develop, implement and evaluate retention strategies. More information is needed on the management and leadership capacities of nursing directors in addition to their span of control. Nursing directors are facing challenges in retaining their nurses. If these problems are not addressed, Lebanon will continue to lose competent and skilled nurses.

Enhancing Nitrogen Availability, Ammonium Adsorption-Desorption, and Soil pH Buffering Capacity using Composted Paddy Husk

Science.gov (United States)

Latifah, O.; Ahmed, O. H.; Abdul Majid, N. M.

2017-12-01

Form of nitrogen present in soils is one of the factors that affect nitrogen loss. Nitrate is mobile in soils because it does not absorb on soil colloids, thus, causing it to be leached by rainfall to deeper soil layers or into the ground water. On the other hand, temporary retention and timely release of ammonium in soils regulate nitrogen availability for crops. In this study, composted paddy husk was used in studies of soil leaching, buffering capacity, and ammonium adsorption and desorption to determine the: (i) availability of exchangeable ammonium, available nitrate, and total nitrogen in an acid soil after leaching the soil for 30 days, (ii) soil buffering capacity, and (iii) ability of the composted paddy husk to adsorb and desorb ammonium from urea. Leaching of ammonium and nitrate were lower in all treatments with urea and composted paddy husk compared with urea alone. Higher retention of soil exchangeable ammonium, available nitrate, and total nitrogen of the soils with composted paddy husk were due to the high buffering capacity and cation exchange capacity of the amendment to adsorb ammonium thus, improving nitrogen availability through temporary retention on the exchange sites of the humic acids of the composted paddy husk. Nitrogen availability can be enhanced if urea is amended with composted paddy husk.

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)

Spatial targeting of conservation tillage to improve water quality and carbon retention benefits

International Nuclear Information System (INIS)

Yang, W.; Sheng, C.; Voroney, P.

2005-01-01

Conservation tillage reduces soil erosion and improves water quality in agricultural watersheds. However, the benefits of conservation tillage in carbon sequestration are the subject of controversy. Public funds are provided to farms to encourage the adoption of conservation tillage. Given the economic costs, the targeting of areas likely to achieve the greatest environmental benefits has become an important policy-making issue. A geographic information system (GIS) based modelling framework which integrated hydrologic, soil organic matter, and farm models to evaluate the spatial targeting of conservation tillage was presented. A case study applying the framework in the Fairchild Creek watershed in Ontario indicated that targeting conservation tillage based on sediment abatement goals can achieve comparable carbon retention benefits in terms of the percentage reduction of base carbon losses. Targeted subcatchments for conservation tillage varied across the watershed based on benefit to cost ratios. Conservation tillage patterns based on carbon retention goals showed similar results to sediment abatement goals but slight differences were observed because of different carbon content in the soils. The results indicated that sediment abatement may be used as an indicator in setting up program goals. The impacts of conservation programs can then be evaluated based on calibrated and validated hydrologic models in conjunction with monitoring data. Results also showed that setting carbon retention may lead to higher costs in order to achieve corresponding sediment abatement benefits. Carbon retention may not be suitable for setting as a stand-alone environmental goal for conservation programs because of the difficulties in verifying the impacts and the discrepancies between carbon and sediment benefits. It was concluded that the modelling results have important policy implications for the design of conservation stewardship programs that aim to achieve environmental

Utilization of wheat straw for the preparation of coated controlled-release fertilizer with the function of water retention.

Science.gov (United States)

Xie, Lihua; Liu, Mingzhu; Ni, Boli; Wang, Yanfang

2012-07-18

With the aim of improving fertilizer use efficiency and minimizing the negative impact on the environment, a new coated controlled-release fertilizer with the function of water retention was prepared. A novel low water solubility macromolecular fertilizer, poly(dimethylourea phosphate) (PDUP), was "designed" and formulated from N,N'-dimethylolurea (DMU) and potassium dihydrogen phosphate. Simultaneously, an eco-friendly superabsorbent composite based on wheat straw (WS), acrylic acid (AA), 2-acryloylamino-2-methyl-1-propanesulfonic acid (AMPS), and N-hydroxymethyl acrylamide (NHMAAm) was synthesized and used as the coating to control the release of nutrient. The nitrogen release profile and water retention capacity of the product were also investigated. The degradation of the coating material in soil solution was studied. Meanwhile, the impact of the content of N-hydroxymethyl acrylamide on the degradation extent was examined. The experimental data showed that the product with good water retention and controlled-release capacities, being economical and eco-friendly, could be promising for applications in agriculture and horticulture.

The potential of hybrid forward osmosis membrane bioreactor (FOMBR) processes in achieving high throughput treatment of municipal wastewater with enhanced phosphorus recovery.

Science.gov (United States)

Qiu, Guanglei; Zhang, Sui; Srinivasa Raghavan, Divya Shankari; Das, Subhabrata; Ting, Yen-Peng

2016-11-15

Extensive research in recent years has explored numerous new features in the forward osmosis membrane bioreactor (FOMBR) process. However, there is an aspect, which is revolutionary but not yet been investigated. In FOMBR, FO membrane shows high rejection for a wide range of soluble contaminants. As a result, hydraulic retention time (HRT) does not correctly reflect the nominal retention of these dissolved contaminants in the bioreactor. This decoupling of contaminants retention time (CRT, i.e. the nominal retention of the dissolved contaminants) from HRT endows FOMBR a potential in significantly reducing the HRT for wastewater treatment. In this work, we report our results in this unexplored treatment potential. Using real municipal wastewater as feed, both a hybrid microfiltration-forward osmosis membrane bioreactor (MF-FOMBR) and a newly developed hybrid biofilm-forward osmosis membrane bioreactor (BF-FOMBR) achieved high removal of organic matter and nitrogen under HRT of down to 2.0 h, with significantly enhanced phosphorus recovery capacities. In the BF-FOMBR, the used of fixed bed biofilm not only obviated the need of additional solid/liquid separation (e.g. MF) to extract the side-stream for salt accumulation control and phosphorus recovery, but effectively quarantined the biomass from the FO membrane. The absence of MF in the side-stream further allowed suspended growth to be continuously removed from the system, which produced a selection pressure for the predominance of attached growth. As a result, a significant reduction in FO membrane fouling (by 24.7-54.5%) was achieved in the BF-FOMBR due to substantially reduced bacteria deposition and colonization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of leaf retention on cutting propagation of Lavandula dentata L.

Directory of Open Access Journals (Sweden)

Claudine Maria de Bona

2010-08-01

Full Text Available Vegetative propagation of lavender offers several advantages over sexual propagation, among them crop homogeneity and yield of higher quality essential oil. However, Lavandula species have been propagated mostly by seeds and are said to be recalcitrant to rooting when propagated by cuttings. During cutting propagation, one of the important variables that influence the rooting capacity of cuttings is the leaf retention. The objective of this work was to evaluate the influence of leaf retention on rooting of L. dentata cuttings. Apical cuttings of L. dentata of 10 cm in length, keeping approximately 1/3, 1/2 or 2/3 of their leaves were planted in commercial substrate Plantmax HT® under intermittent mist. After two months, averages of root number, length of the longest root, root fresh and dry weights, and the survival percentage were evaluated. Root length and fresh weight were statistically greater with 2/3 of leaf retention and when fewer leaves were kept on the cuttings, lower means of root dry weight was observed. Under the conditions applied in this study, greater leaf retention was better for rooting of L. dentata cuttings.

Capacity market design and renewable energy: Performance incentives, qualifying capacity, and demand curves

Energy Technology Data Exchange (ETDEWEB)

Botterud, Audun; Levin, Todd; Byers, Conleigh

2018-01-01

A review of capacity markets in the United States in the context of increasing levels of variable renewable energy finds substantial differences with respect to incentives for operational performance, methods to calculate qualifying capacity for variable renewable energy and energy storage, and demand curves for capacity. The review also reveals large differences in historical capacity market clearing prices. The authors conclude that electricity market design must continue to evolve to achieve cost-effective policies for resource adequacy.

The Effect of Perceptual Learning on L2 Vocabulary Learning and Retention

OpenAIRE

BEDİR, Gülay; BEKTAŞ BEDİR, Sevgi

2018-01-01

It is thought that learning styles have an effecton learning foreign language. This study aims to determine effects ofperceptual learning styles on L2 vocabulary learning and retention. Learningstyle preferences were assessed in the current study through the section ofCohen et al.’s Learning Style Survey (LSS) corresponding to the perceptualmodalities and achievement tests developed by the researcher was used to assessvocabulary learning and retention. And an open-ended question is tried toan...

Capacity Estimation and Near-Capacity Achieving Techniques for Digitally Modulated Communication Systems

DEFF Research Database (Denmark)

Yankov, Metodi Plamenov

investigation will include linear interference channels of high dimensionality (such as multiple-input multiple-output), and the non-linear optical fiber channel, which has been gathering more and more attention from the information theory community in recent years. In both cases novel CCC estimates and lower......This thesis studies potential improvements that can be made to the current data rates of digital communication systems. The physical layer of the system will be investigated in band-limited scenarios, where high spectral efficiency is necessary in order to meet the ever-growing data rate demand....... Several issues are tackled, both with theoretical and more practical aspects. The theoretical part is mainly concerned with estimating the constellation constrained capacity (CCC) of channels with discrete input, which is an inherent property of digital communication systems. The channels under...

Retention of elemental 131I by activated carbons under accident conditions

International Nuclear Information System (INIS)

Deuber, H.

1984-09-01

Under simulated accident conditions (maximum temperature: 130 0 C) no significant difference was found in the retention of I-131 loaded as elemental iodine, by various fresh and aged commercial activated carbons. In all the cases, the I-131 passing through deep beds of activated carbon was in a non-elemental form. It is concluded that a minimum retention of 99.99% for elemental radioiodine, as required by the RSK guidelines for PWR accident filters, can be equally well achieved with various commercial activated carbons. (orig.) [de

Lace-Espana experimental programme on the retention of aerosols in water pools

Energy Technology Data Exchange (ETDEWEB)

Marcos, M. J.; Gomez, F. J.; Melches, I.; Martin, M.; Lopez, M.

1994-07-01

A matrix of eleven experiments on aerosol retention behaviour in submerged beds and suppression pools in water- cooled reactors under severe accident conditions has been performed, for these experiments, an intermediate scales, multi-purpose facility was set up at CIEMAT (Madrid). The facility includes various systems: aerosol generation (Csl), mixing section, injection line and pool-vessel (8 m{sup 3} ), as well as the corresponding aerosol instrumentation and a process control and data acquisition system. Some parameters have been varied in order to study their influence in the DF: steam/noncondensable ratio in the accidental mixture (0.1 to 0.9), particle size, flow rate (two regimes: bubble and jet) and injector geometry (mono orifice and multi orifice). On the other hand, some parameters have been kept constant along the experiments; pool geometry (diameter, water level), water temperature, pressure in the atmosphere above the water, submergence, injection temperature and injection time. A rapid decrease in the DF is observed as the proportion of particles measuring less than 1 {mu}m increases. Retention decreases in the case of smaller particles and considerably higher in the case of larger particles. It has been also possible to observe the influence of the injected steam fraction. Experiments with greater fraction than the saturation fraction have greater DF than those ones with smaller fractions. The jet regime with horizontal injection and the multi orifice geometry would appear to show a somewhat higher capacity of retention than those in the bubble regime under similar conditions. It would be necessary to confirm this greater capacity for retention by means of additional experimental data. This work, performed by the LACE-Espana Consortium, has been carried out in the frame of the European Commissions Shared Cost Action Programme on Reactor Safety 1988-91 on a contractual basis. (Author)18 refs.

Lace-Espana experimental programme on the retention of aerosols in water pools

International Nuclear Information System (INIS)

Marcos, M. J.; Gomez, F. J.; Melches, I.; Martin, M.; Lopez, M.

1994-01-01

A matrix of eleven experiments on aerosol retention behaviour in submerged beds and suppression pools in water- cooled reactors under severe accident conditions has been performed, for these experiments, an intermediate scales, multi-purpose facility was set up at CIEMAT (Madrid). The facility includes various systems: aerosol generation (Csl), mixing section, injection line and pool-vessel (8 m 3 ), as well as the corresponding aerosol instrumentation and a process control and data acquisition system. Some parameters have been varied in order to study their influence in the DF: steam/noncondensable ratio in the accidental mixture (0.1 to 0.9), particle size, flow rate (two regimes: bubble and jet) and injector geometry (mono orifice and multi orifice). On the other hand, some parameters have been kept constant along the experiments; pool geometry (diameter, water level), water temperature, pressure in the atmosphere above the water, submergence, injection temperature and injection time. A rapid decrease in the DF is observed as the proportion of particles measuring less than 1 μm increases. Retention decreases in the case of smaller particles and considerably higher in the case of larger particles. It has been also possible to observe the influence of the injected steam fraction. Experiments with greater fraction than the saturation fraction have greater DF than those ones with smaller fractions. The jet regime with horizontal injection and the multi orifice geometry would appear to show a somewhat higher capacity of retention than those in the bubble regime under similar conditions. It would be necessary to confirm this greater capacity for retention by means of additional experimental data. This work, performed by the LACE-Espana Consortium, has been carried out in the frame of the European Commissions Shared Cost Action Programme on Reactor Safety 1988-91 on a contractual basis. (Author)18 refs

Lace-Espana experimental programme on the retention of aerosols in water pools

International Nuclear Information System (INIS)

Marcos Crespo, M.J.; Gomez; Moreno, F. J.; Melches Serrano, I.; Martin Espigares, M.; Lopez Jimenez, J.

1994-01-01

A matrix of eleven experiments on aerosol retention behaviour in submerged beds and suppression pools in water-cooled reactors under severe accident conditions has been performed, for these experiments, an intermediate scale, multi-purpose facility was set up at CIEMAT (Madrid). The facility includes various systems: aerosol ageneration (CsI), mixing section, injection line and pool-vessel (8 m''3), as well as the corresponding aerosol instrumentation and a process control and data acquisition system. Some parameters have been varied in order to study their influence in the DF: steam/noncondensable ratio in the accidental mixture (0,1 to 0.9) particle size, flow rate (two regimes: bubble and jet) and injector geometry (monoorifice and multiorifice). On the other hand, some parameters have been kept constant along the experiments; pool geometry (diameter, water level), water temperature, pressure in the atmosphere above the water, submergence, injection temperature and injection time. A Rapid decrease in the DF is observed as the proportion of particles measuring les than 1 mum increases. Retention decreases in the case of smaller particles and considerably higher in the case of larger particles. It has been also possible to observe the influence of the injected steam fraction. Experiments with greater fraction than the saturation fraction have greater DF than those ones with smaller fractions. The jet regime with horizontal injection and the multiorifice geometry would appear to show a somewhat higher capacity of retention than those in the bubble regime under similar conditions. It would be necessary to confirm this greater capacity for retention by means of additional experimental data. This work, performed by the LACE-Espana Consortium, has been carried out in the frame of the European Commission's Shared Cost Action Programme on Reactor Safety 1988-91 on a contractual basis

Influence of DMPS on the water retention capacity of electroporated stratum corneum: ATR-FTIR study.

Science.gov (United States)

Sckolnick, Maria; Hui, Sek-Wen; Sen, Arindam

2008-02-28

Anionic lipids like phosphatidylserine are known to significantly enhance electroporation mediated transepidermal transport of polar solutes of molecular weights up to 10kDa. The underlying mechanism of the effect of anionic lipids on transdermal transport is not fully understood. The main barrier to transdermal transport lies within the intercellular lipid matrix (ILM) of the stratum corneum (SC) and our previous studies indicate that dimyristoyl phosphatidylserine (DMPS) can perturb the packing of this lipid matrix. Here we report on our investigation on water retention in the SC following electroporation in the presence and the absence of DMPS. The water content in the outer most layers of the SC of full thickness porcine skin was determined using ATR-FTIR-spectroscopy. The results show that in the presence of DMPS, the SC remains in a state of enhanced hydration for longer periods after electroporation. This increase in water retention in the SC by DMPS is likely to play an important role in trans-epidermal transport, since improved hydration of the skin barrier can be expected to increase the partitioning of polar solutes and possibly the permeability.

Evolution of the concept of Capacity-building, results achieved during the past years and the future

Science.gov (United States)

Laffaiteur, M.; Camacho, S.

Capacity-building is one of the key elements for the implementation of space applications programmes, particularly in developing countries. As early as 1982, the work programme of the United Nations Programme on Space Applications was expanded in order to promote education and training by organizing seminars, training courses and workshops in various areas, such as astronomy, telecommunications and Earth observation. In the framework of this Programme, the Office for Outer Space Affairs undertook the initiative, at the beginning of the 1990's, aimed at establishing regional centres for space science and technology education, affiliated to the United Nations and located in developing countries. These centres have started their activities between 1995 and 2000 in Africa, Asia and the Pacific, and Latin America and the Caribbean. The centres are based on the concept that by pooling material and human resources, developing countries can have education and training centres, of an international-level quality. A considerable impetus has been given to capacity-building after the UNISPACE III Conference, in particular in the "Vienna Declaration on Space and Human Development". The necessity to enhance capacity-building through the development of human and budgetary resources, the training of teachers, the exchange of teaching methods, materials and experience and the development of infrastructure and policy regulatories. In the process of the implementation of the recommendations of UNISPACE III, Action Teams led by Governments were established. One of them was exclusively dealing with capacity-building. Its proposals have been reviewed last June by the Committee on the Peaceful Uses of Outer Space (COPUOS) and will be examined, among other reports of Action Teams, by the General Assembly in next October. A lot of work has been done during the past years and have produced very important results. But there is still an important gap in capacity-building between space

Avoiding The Inevitable? Capacity Loss From Reservoir Sedimentation

Science.gov (United States)

Gray, John R.; Randle, Timothy J.; Collins, Kent L.

2013-01-01

The inexorable loss of capacity of the nation's reservoirs—sooner or later threatening water supplies for municipal, agricultural, and industrial uses—is but one of a number of deleterious effects wrought by sediment deposition. Trapped sediments can also damage or bury dam outlets, water intakes, and related infrastructure. Downstream effects of sediment capture and retention by reservoirs can include channel and habitat degradation and biotic alterations.

Exploring Psychological and Aesthetic Approaches of Bio-Retention Facilities in the Urban Open Space

Directory of Open Access Journals (Sweden)

Suyeon Kim

2017-11-01

Full Text Available Over the last decades, a number of bio-retention facilities have been installed in urban areas for flood control and green amenity purposes. As urban amenity facilities for citizens, bio-retentions have a lot potential; however, the literature on bio-retentions focused mostly on physiochemical aspects like water quality and runoffs. Hence, this paper aims to explore psychological aspects of bio-retentions such as perceptions and landscape aesthetic value for visitors. In order to achieve this purpose, the study employed on-site interviews and questionnaires in the chosen three case studies as research methodology. For the 3 different locations of bio-retention facilities, interviews and questionnaires were carried out. The surveys of 100 bio-retention users were conducted, investigating their general perceptions and landscape aesthetics of the bio-retention facilities. The paper found that only 34% of the interviewees recognised bio-detention facilities, illustrating that most visitors were not aware of such facilities and were unable to distinguish the differences between bio-retention and conventional gardens. On the other hand, the majority of interviewees strongly supported the concept and function of bio-retentions, especially those who recognised the differences in planting species with conventional urban open spaces. Such main findings also encourage further studies of seeking quantitative values by conducting a correlation analysis between the functions and aesthetics of bio-retention facilities.

Optimization of an M/M/1/N Feedback Queue with Retention of Reneged Customers

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Rakesh Kumar

2014-01-01

Full Text Available Customer impatience has become a threat to the business world. Firms employ various customer retention strategies to retain their impatient (or reneged customers. Customer retention mechanisms may help to retain some or all impatient customers. Further, due to unsatisfactory service, customers may rejoin a queue immediately after departure. Such cases are referred to as feedback customers. Kumar and Sharma take this situation into account and study an M/M/1/N feedback queuing system with retention of reneged customers. They obtain only a steady-state solution for this model. In this paper, we extend the work of Kumar and Sharma by performing an economic analysis of the model. We develop a model for the costs incurred and perform the appropriate optimization. The optimum system capacity and optimum service rate are obtained. (original abstract

Co-emergence of multi-scale cortical activities of irregular firing, oscillations and avalanches achieves cost-efficient information capacity.

Directory of Open Access Journals (Sweden)

Dong-Ping Yang

2017-02-01

Full Text Available The brain is highly energy consuming, therefore is under strong selective pressure to achieve cost-efficiency in both cortical connectivities and activities. However, cost-efficiency as a design principle for cortical activities has been rarely studied. Especially it is not clear how cost-efficiency is related to ubiquitously observed multi-scale properties: irregular firing, oscillations and neuronal avalanches. Here we demonstrate that these prominent properties can be simultaneously observed in a generic, biologically plausible neural circuit model that captures excitation-inhibition balance and realistic dynamics of synaptic conductance. Their co-emergence achieves minimal energy cost as well as maximal energy efficiency on information capacity, when neuronal firing are coordinated and shaped by moderate synchrony to reduce otherwise redundant spikes, and the dynamical clusterings are maintained in the form of neuronal avalanches. Such cost-efficient neural dynamics can be employed as a foundation for further efficient information processing under energy constraint.

Meltwater retention in a transect across the Greenland ice sheet

DEFF Research Database (Denmark)

Bøggild, Carl Egede; Forsberg, René; Reeh, Niels

2005-01-01

by different physical mechanisms, their potential magnitude can be estimated, which has been done in a transect at 66 degrees N. Results show that SI declines from west to east and inversely correlates with accumulation. From the total retention capacity, theoretical lowest-runoff lines were determined......Meltwater retention by freezing is a highly climate-sensitive term in the mass budget since the cold content is directly controlled by winter climate, which is expected to change most in an anthropogenic-driven climate change. Meltwater released at the surface percolates into dry snow in a pattern...... with alternating horizontal and vertical water-flow directions, where the processes of pore refreezing (RF) (vertical flow) and superimposed ice (SI) formation (horizontal flow) occur. The flow cannot be forecasted and quantified when water first enters cold, dry snow. However, because the two processes are driven...

Achieving increased spent fuel storage capacity at the High Flux Isotope Reactor (HFIR)

International Nuclear Information System (INIS)

Cook, D.H.; Chang, S.J.; Dabs, R.D.; Freels, J.D.; Morgan, K.A.; Rothrock, R.B.; Griess, J.C.

1994-01-01

The HFIR facility was originally designed to store approximately 25 spent cores, sufficient to allow for operational contingencies and for cooling prior to off-site shipment for reprocessing. The original capacity has now been increased to 60 positions, of which 53 are currently filled (September 1994). Additional spent cores are produced at a rate of about 10 or 11 per year. Continued HFIR operation, therefore, depends on a significant near-term expansion of the pool storage capacity, as well as on a future capability of reprocessing or other storage alternatives once the practical capacity of the pool is reached. To store the much larger inventory of spent fuel that may remain on-site under various future scenarios, the pool capacity is being increased in a phased manner through installation of a new multi-tier spent fuel rack design for higher density storage. A total of 143 positions was used for this paper as the maximum practical pool capacity without impacting operations; however, greater ultimate capacities were addressed in the supporting analyses and approval documents. This paper addresses issues related to the pool storage expansion including (1) seismic effects on the three-tier storage arrays, (2) thermal performance of the new arrays, (3) spent fuel cladding corrosion concerns related to the longer period of pool storage, and (4) impacts of increased spent fuel inventory on the pool water quality, water treatment systems, and LLLW volume

Preparation and Properties of a Novel Semi-IPN Slow-Release Fertilizer with the Function of Water Retention.

Science.gov (United States)

Xiang, Yang; Ru, Xudong; Shi, Jinguo; Song, Jiang; Zhao, Haidong; Liu, Yaqing; Guo, Dongdong; Lu, Xin

2017-12-20

A new semi-interpenetrating polymer network (semi-IPN) slow-release fertilizer (SISRF) with water absorbency, based on the kaolin-g-poly(acrylic acid-co-acrylic amide) (kaolin-g-P(AA-co-AM)) network and linear urea-formaldehyde oligomers (UF), was prepared by solution polymerization. Nutrients phosphorus and potassium were supplied by adding dipotassium hydrogen phosphate during the preparation process. The structure and properties of SISRF were characterized by various characterization methods. SISRF showed excellent water absorbency of 68 g g -1 in tap water. The slow-release behavior of nutrients and water-retention capacity of SISRF were also measured. Meanwhile, the swelling kinetics was well described by a pseudo-second-order kinetics model. Results suggested the formation of SISRF with simultaneously good slow-release and water-retention capacity, which was expected to apply in modern agriculture and horticulture.

MIMO Intensity-Modulation Channels: Capacity Bounds and High SNR Characterization

KAUST Repository

Chaaban, Anas

2016-10-01

The capacity of MIMO intensity modulation channels is studied. The nonnegativity of the transmit signal (intensity) poses a challenge on the precoding of the transmit signal, which limits the applicability of classical schemes in this type of channels. To resolve this issue, capacity lower bounds are developed by using precoding-free schemes. This is achieved by channel inversion or QR decomposition to convert the MIMO channel to a set of parallel channels. The achievable rate of a DC-offset SVD based scheme is also derived as a benchmark. Then, a capacity upper bound is derived and is shown to coincide with the achievable rate of the QR decomposition based scheme at high SNR, consequently characterizing the high-SNR capacity of the channel. The high-SNR gap between capacity and the achievable rates of the channel inversion and the DC-offset SVD based schemes is also characterized. Finally, the ergodic capacity of the channel is also briefly discussed.

Continuously Growing Ultrathick CrN Coating to Achieve High Load-Bearing Capacity and Good Tribological Property.

Science.gov (United States)

Li, Zechao; Wang, Yongxin; Cheng, Xiaoying; Zeng, Zhixiang; Li, Jinlong; Lu, Xia; Wang, Liping; Xue, Qunji

2018-01-24

Continuous growth of traditional monolayer CrN coatings up to 24 h is successfully achieved to fabricate ultrathickness of up to 80 μm on the 316 stainless steel substrate using a multiarc ion plating technique. The microstructures, mechanical properties, and tribological properties evolution with the CrN coating continuously growing was evaluated in detail. The transmission electron microscopy observations and inverse Fourier-filtered images reveal a relaxation mechanism during the continuous growth of CrN coating, which can lead to a decrease in the residual stress when coating growth time exceeds 5 h. The scratch test and friction test results both show that the load-bearing capacity of coating is significantly increased as CrN coatings growing thicker. During the scratch test, the ultrathick CrN coating of thickness 80.6 μm is not failed under the load of 180 N, and the dominant failure mechanism is the cohesive failure including wedge spallation and cracking. The dry-sliding friction test results show the mean coefficient of friction and the wear rate of ultrathick CrN are respectively decreased by 17.2 and 56.8% at most compared with the thin coating (thickness is 5.4 μm). The ultrahigh load-bearing capacity and excellent tribological property are attributed to the relaxation mechanism and limited contact pressure as the coating grows continuously.

The Implementation of Knowledge Strategy-Based Entrepreneurial Capacity to Achieve Sustainable Competitive Advantage

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Widodo

2013-08-01

Full Text Available This study aims to develop a model of knowledge strategy-based entrepreneurial capacity to achieve sustainable competitive advantage of rurol banking in Central Java province. The sampling method is ‘‘Purposive sampling’’ by considering the characteristics of the population items, namely: operational experience for at least 5 years and representatives of each area of rurol banking in Semarang, Surakarta and Purwokerto. Then, the sample size is 150 of 251 (59.7% of top managers of rurol banking. To analyze the data in this study, it used the Structural Equation Modeling (SEM, of the, AMOS software package. The findings of this study explain that 1. The first step in promoting a sustainable competitive advantage through knowledge sharing is by prioritizing the quality of interaction, willingness and ability. 2. Efforts to improve a sustainable competitive advantage through knowledge exploitation built by knowledge sharing are by prioritizing to actively accept changes and introduction, solve problems together, use and combine new knowledge in operation. 3. Efforts to improve a sustainable competitive advantage through the knowledge exploitation built by risk-taking are by prioritizing a strong tendency for high-risk projects (with the possibility of gaining high-return, a high courage for the actions necessary to achieve the goal, having an aggressive attitude to optimize the possibility of utilizing existing potential opportunities and enjoying the challenge of the risk situation. 4. Efforts to improve a sustainable competitive advantage through knowledge exploitation built by a pro-active are by prioritizing to anticipate problem more quickly than competitors, future oriented, addressed by technology, launching product selectively and systematically search for new ideas. 5. Efforts to improve a sustainable competitive advantage through knowledge exploitation built by the innovativeness are by prioritizing the speed of developing products

An economic assessment of local farm multi-purpose surface water retention systems in a Canadian Prairie setting

Science.gov (United States)

Berry, Pamela; Yassin, Fuad; Belcher, Kenneth; Lindenschmidt, Karl-Erich

2017-12-01

There is a need to explore more sustainable approaches to water management on the Canadian Prairies. Retention pond installation schemes designed to capture surface water may be a viable option that would reduce water stress during drought periods by providing water for irrigation. The retention systems would serve to capture excess spring runoff and extreme rainfall events, reducing flood potential downstream. Additionally, retention ponds may be used for biomass production and nutrient retention. The purpose of this research was to investigate the economic viability of adopting local farm surface water retention systems as a strategic water management strategy. A retention pond was analyzed using a dynamic simulation model to predict its storage capacity, installation and upkeep cost, and economic advantage to farmers when used for irrigation. While irrigation application increased crop revenue, the cost of irrigation and reservoir infrastructure and installation costs were too high for the farmer to experience a positive net revenue. Farmers who harvest cattails from retention systems for biomass and available carbon offset credits can gain 642.70/hectare of harvestable cattail/year. Cattail harvest also removes phosphorus and nitrogen, providing a monetized impact of 7014/hectare of harvestable cattail/year. The removal of phosphorus, nitrogen, carbon, and avoided flooding damages of the retention basin itself provide an additional 17,730-18,470/hectare of retention system/year. The recommended use of retention systems is for avoided flood damages, nutrient retention, and biomass production. The revenue gained from these functions can support farmers wanting to invest in irrigation while providing economic and environmental benefits to the region.

Considering clay rock heterogeneity in radionuclide retention

International Nuclear Information System (INIS)

Grambow, B.; Montavon, G.; Tournassat, C.; Giffaut, E.; Altmann, S.

2010-01-01

Document available in extended abstract form only. The Callovo-Oxfordian clay rock formation has a strong retention capacity for radionuclides, a favorable condition for the implementation of a nuclear waste repository. Principal retaining minerals are illite, and inter-stratified illite/smectite (I/S). Radionuclide retention has been studied on illite, illite/smectite and on clay rock obtained from different locations and data for retention on bentonite (80% smectite) are available. Sorption depends on the type of mineral, composition of mineralogical assemblages, individual mineral ion exchange capacities, ion distribution on exchange sites, specific surface areas, surface site types and densities for surface complexation as well as on water/rock ratios, temperature etc. As a consequence of mineralogical and textural variations, radionuclide retention properties are expected to vary with depth in the Callovo-Oxfordian formation. Using a simple additivity approach for the case of sorption of Cs and Ni it is shown that models and databases for illite and bentonite can be used to describe sorption in heterogeneous clay rock systems. A surface complexation/ion-exchange model as proposed by Bradbury and Baeyens without electrostatic contributions, was used directly as far as acid base properties are concerned but was modified with respect to sorption constants, in order to describe Na-, Ca, and Cs montmorillonite and bentonite MX-80 with a single set of surface complexation constants and also to account for carbonate and sulphate concentrations in groundwater. The model is integrated into the geochemical code PHREEQC considering dissolution/ precipitation/solubility constraints of accessory minerals (calcite, illite, celestite, quartz). Site densities for surface complexation and ion exchange are derived from the mass fractions of illite and of smectite in illite/smectite obtained from an overall fit of measured CEC data from all samples of the EST205 drill core

Effect of biochar amendment on nitrate retention in a silty clay loam soil

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Angela Libutti

2016-08-01

Full Text Available Biochar incorporation into agricultural soils has been proposed as a strategy to decrease nutrient leaching. The present study was designed to assess the effect of biochar on nitrate retention in a silty clay loam soil. Biochar obtained from the pyrogasification of fir wood chips was applied to soil and tested in a range of laboratory sorption experiments. Four soil treatments were considered: soil only (control, soil with 2, 4 and 8% of biochar by mass. The Freundlich sorption isotherm model was used to fit the adsorbed amount of nitrate in the soil-biochar mixtures. The model performed very well in interpreting the experimental data according to a general linear regression (analysis of co-variance statistical approach. Nitrate retention in the soilbiochar mixtures was always higher than control, regardless the NO3 – concentration in the range of 0-400 mg L–1. Different sorption capacities and intensities were detected depending on the biochar application rate. The highest adsorption capacity was observed in the soils added with 2 and 4% of biochar, respectively. From the results obtained is possible to infer that nitrate retention is higher at lower biochar addition rate to soil (2 and 4% and at lower nitrate concentration in the soil water solution. These preliminary laboratory results suggest that biochar addition to a typical Mediterranean agricultural soil could be an effective management option to mitigate nitrate leaching.

Sodalite as a vehicle to increase Re retention in waste glass simulant during vitrification

Energy Technology Data Exchange (ETDEWEB)

Luksic, Steven A., E-mail: steven.luksic@pnnl.gov; Riley, Brian J.; Parker, Kent E.; Hrma, Pavel

2016-10-15

Technetium (Tc) retention during Hanford waste vitrification can be increased if the volatility can be controlled. Incorporating Tc into a thermally stable mineral phase, such as sodalite, is one way to achieve increased retention. Here, rhenium (Re)-bearing sodalite was tested as a vehicle to transport perrhenate (ReO{sub 4}{sup −}), a nonradioactive surrogate for pertechnetate (TcO{sub 4}{sup −}), into high-level (HLW) and low-activity waste (LAW) glass simulants. After melting HLW and LAW simulant feeds, the retention of Re in the glass was measured and compared with the Re retention in glass prepared from a feed containing Re{sub 2}O{sub 7}. Phase analysis of sodalite in both these glasses across a profile of temperatures describes the durability of Re-sodalite during the feed-to-glass transition. The use of Re sodalite improved the Re retention by 21% for HLW glass and 85% for LAW glass, demonstrating the potential improvement in Tc-retention if TcO{sub 4}{sup −} were to be encapsulated in a Tc-sodalite prior to vitrification. - Highlights: • Re retention is improved by incorporation into sodalite structure. • LAW-type glass shows lower retention but larger improvement with Re-sodalite. • Sodalite is stable to higher temperatures in high-alumina glass melts.

Enhanced protein retention on poly(caprolactone) via surface initiated polymerization of acrylamide

International Nuclear Information System (INIS)

Ma, Yuhao; Cai, Mengtan; He, Liu; Luo, Xianglin

2016-01-01

Graphical abstract: - Highlights: • Dense package of poly(acrylamide) on poly(caprolactone) surface was achieved by surface-initiated atom transfer radical polymerization. • Poly(acrylamide) grafted surface exhibited high protein retention ability. • Loaded protein was resistant to detachment and maintained its structure without denaturation. - Abstract: To enhance the biocompatibility or extend the biomedical application of poly(caprolactone) (PCL), protein retention on PCL surface is often required. In this study, poly(acrylamide) (PAAm) brushes were grown from PCL surface via surface-initiated atom transfer radical polymerization (SI-ATRP) and served as a protein-capturing platform. Grafted PAAm was densely packed on surface and exhibited superior protein retention ability. Captured protein was found to be resistant to washing under detergent environment. Furthermore, protein structure after being captured was investigated by circular dichroism (CD) spectroscopy, and the CD spectra verified that secondary structure of captured proteins was maintained, indicating no denaturation of protein happened for retention process.

Water Retention in a Small Agricultural Catchment and its Potential Improvement by Design of Water Reservoirs – A Case Study of the Bílý Potok Catchment (Czechia

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Doležal Petr

2018-03-01

Full Text Available Water retention in the landscape is discussed in the context of conservation and improvement of both its productive and non-productive functions. We analysed the retention potential of a small agricultural catchment associated with the Bílý potok brook, investigating the possibility to improve its retention capacity and slow down the surface runoff, thus increasing the underground water resources. Method of curve numbers was used for that purposes. From results, it emerged that present maximum water retention in the Bílý potok catchment is 96.2 mm. It could increase by 101.3 mm in case of grassing about 20% arable land threatened by soil erosion. As next possibility to retain water from precipitations in landscape, capacity and transformation effect of reservoirs designed in master plans was analysed. The latest programming tools working in the GIS environment were used to assess the retention capacity of both the catchment surface and the reservoirs. Analysing master plans in the catchment, it was found that 16 designed water reservoirs (from 31 have a good potential to intercept water and transform flood discharges. In the result, priority for building of reservoirs was recommended according to their pertinence and efficiency in the studied catchment. Presented complex approach can be widely implemented, especially for better effectivity and cohesion of landscape planning and land consolidations processes.

Evaluating Retention-Driven Marketing in a Community College: An Alternative Approach.

Science.gov (United States)

Tichenor, Richard; Cosgrove, John J.

1991-01-01

Community colleges need to adopt a broad conceptual definition of a continuing student in the design and evaluation of their retention strategies, recognizing nondegree goals as legitimate educational achievements and intermittent but persistent attendance as a valid method of pursuing educational goals. (MSE)

Nanosericite as an Innovative Microparticle in Dual-Chemical Paper Retention Systems

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Yuan-Shing Perng

2013-01-01

Full Text Available Dual-chemical retention systems based on 2 cationic polyacrylamides, a colloidal silica, and a globular anionic polymer microparticles were investigated and an exfoliated nanoparticle indigenous mica mineral, sericite, was examined for its efficacy in substituting commercial microparticle preparations. The results indicated that nanosericite generated FPR between 76.9 and 80.9% for fines and chemicals. Its ash retention values, however, were higher and tended to increase with doses of polymer, nanosericite, or Sc to between 16 and 24%. As for paper physical properties, nanosericite was not amenable to substitute the c-PAMb/polymer with only handsheet stiffness superior to the combination. Nanosericite, however, showed good substitution capacity than the c-PAMa-colloidal silica combination. Regardless of the c-PAMa doses, all examined handsheet physical properties incorporating nanosericite were superior to colloidal silica. The optimal performance was observed with c-PAMa dose of 200 ppm. Optical properties of the handsheets indicated that with nanosericite substitution, brightness values were comparable to the polymer group, while its substitution capacity for colloidal silica decreased with increasing c-PAMb dose. Only at c-PAMa dose of 300 ppm, it appeared to have good substitution for colloidal silica. Substituting nanosericite for colloidal silica appeared to reduce the c-PAMa charge and increased the overall cost effectiveness.

The effects of forced-egg retention on the blood-feeding behavior and reproductive potential of Culex pipiens (Diptera: Culicidae).

Science.gov (United States)

Johnson, Brian J; Fonseca, Dina M

2014-07-01

High rates of West Nile virus (WNV) transmission to humans are associated with exceptionally hot and dry summers. This is paradoxical since the eggs of Culex vectors of WNV depend on the persistence of containers with water, which decline during droughts. We examined the effects of forced-egg retention on the reproductive success of female Culex pipiens as well as behavioral responses, such as likelihood of secondary blood meals. As controls we examined the effects of female age and delayed mating. We found that early mating is essential to achieve reproductive success and, consistent with an "all-or-none" ovipositing strategy, C. pipiens females are able to retain considerable reproductive potential while searching for oviposition sites. Specifically, although forced-egg retention resulted in significant decreases in fitness, the decline was moderate for 5 weeks and most can be accounted for by increases in female age. Consequently, no females took blood more than once per gonotrophic cycle, which eliminates the possibility that heightened vectorial capacity due to multiple blood-feedings increases WNV transmission during periods of drought. Instead, our findings suggest that during droughts populations of C. pipiens have time to locate the remaining water holes, which are associated with human populations and WNV-competent bird species. Copyright © 2014. Published by Elsevier Ltd.

Soil Cd, Cr, Cu, Ni, Pb and Zn sorption and retention models using SVM: Variable selection and competitive model.

Science.gov (United States)

González Costa, J J; Reigosa, M J; Matías, J M; Covelo, E F

2017-09-01

The aim of this study was to model the sorption and retention of Cd, Cu, Ni, Pb and Zn in soils. To that extent, the sorption and retention of these metals were studied and the soil characterization was performed separately. Multiple stepwise regression was used to produce multivariate models with linear techniques and with support vector machines, all of which included 15 explanatory variables characterizing soils. When the R-squared values are represented, two different groups are noticed. Cr, Cu and Pb sorption and retention show a higher R-squared; the most explanatory variables being humified organic matter, Al oxides and, in some cases, cation-exchange capacity (CEC). The other group of metals (Cd, Ni and Zn) shows a lower R-squared, and clays are the most explanatory variables, including a percentage of vermiculite and slime. In some cases, quartz, plagioclase or hematite percentages also show some explanatory capacity. Support Vector Machine (SVM) regression shows that the different models are not as regular as in multiple regression in terms of number of variables, the regression for nickel adsorption being the one with the highest number of variables in its optimal model. On the other hand, there are cases where the most explanatory variables are the same for two metals, as it happens with Cd and Cr adsorption. A similar adsorption mechanism is thus postulated. These patterns of the introduction of variables in the model allow us to create explainability sequences. Those which are the most similar to the selectivity sequences obtained by Covelo (2005) are Mn oxides in multiple regression and change capacity in SVM. Among all the variables, the only one that is explanatory for all the metals after applying the maximum parsimony principle is the percentage of sand in the retention process. In the competitive model arising from the aforementioned sequences, the most intense competitiveness for the adsorption and retention of different metals appears between

Retention assessment of magnetic nanoparticles in rat arteries with micro-computed tomography.

Science.gov (United States)

Tu, Shu-Ju; Wu, Siao-Yun; Wang, Fu-Sheng; Ma, Yunn-Hwa

2014-03-07

Magnetic nanoparticles (MNPs) may serve as carriers for pharmacological agents to the target in a magnetic-force guiding system. It is essential to achieve effective retention of MNPs through the external magnet placement. However, it is difficult to estimate the retention efficiency of MNPs and validate the experimental strategies. Micro-CT was used to identify the spatial distribution of MNP retention and image analysis is then extended to evaluate the MNP delivery efficiency. Male Sprague Dawley rats were anesthetized to expose abdominal arteries with an NdFeB magnet of 4.9 kG placed by the left iliac artery. After a 20 min equilibrium period, arteries were ligated, removed and fixed in a paraformaldehyde solution. Experiments were performed with intravenous injection in our platform with two independent groups. MNPs were used in the first group, while chemical compounds of recombinant tissue plaminogen activator were attached to MNPs as rtPA (recombinant tissue plaminogen activator)-MNPs in the second group. Image analysis of micro-CT shows the average retention volume of MNPs and rtPA-MNPs in the left iliac arteries is 9.3 and 6.3 fold of that in the right. Large local aggregation of MNPs and rtPA-MNPs in the left iliac arteries is the consequence of external magnet placement, suggesting feasibility of magnetic targeting through the intravenous administration. We also determined that on average 0.57% and 0.064% of MNPs and rtPA-MNPs respectively were retained in the left iliac artery. It was estimated that the average rtPA concentration of 60.16 µg mL(-1) may be achieved with rtPA-MNPs. With the micro-CT imaging approach, we accomplished visualization of the aggregation of retained particles; reconstructed 3D distribution of relative retention; estimated the average particle number of local retention; determined efficiency of targeted delivery. In particular, our quantitative image assessment suggests that intravenous administration of rtPA-MNPs may retain

The capacity credit of micro-combined heat and power

International Nuclear Information System (INIS)

Hawkes, A.D.; Leach, M.A.

2008-01-01

This article is concerned with development of a methodology to determine the capacity credit of micro-combined heat and power (micro-CHP), and application of the method for the UK. Capacity credit is an important parameter in electricity system planning because it measures the amount of conventional generation that would be displaced by an alternative technology. Firstly, a mathematical formulation is presented. Capacity credit is then calculated for three types of micro-CHP units-Stirling engine, internal combustion engine, and fuel cell systems-operating under various control strategies. It is found that low heat-to-power ratio fuel cell technologies achieve the highest capacity credit of approximately 85% for a 1.1 GW penetration when a heat-led control strategy is applied. Higher heat-to-power ratio Stirling engine technology achieves approximately 33% capacity credit for heat-led operation. Low heat-to-power ratio technologies achieve higher capacity credit because they are able to continue operating even when heat demand is relatively low. Capacity credit diminishes as penetration of the technology increases. Overall, the high capacity credit of micro-CHP contributes to the viewpoint that the technology can help meet a number of economic and environmental energy policy aims

Influence of usual zinc intake and zinc in a meal on 65Zn retention and turnover in the rat

International Nuclear Information System (INIS)

Hunt, J.R.; Johnson, P.E.; Swan, P.B.

1987-01-01

The influences of zinc in a meal and usual zinc intake on zinc retention and turnover were investigated in 7-wk-old male rats fed diets containing 12-151 mg Zn/kg for 3 wk before and after consuming a 65 Zn-labeled meal containing ZnCl 2 . Retention corrected to zero time and turnover rate were determined by whole-body counting. Percent zinc retention was inversely proportional to the natural logarithm of the meal zinc, between 0.09 and 26 mumol. In comparison to lower doses, higher doses resulted in lower percent retention but greater amounts of zinc retained. Although the latter relationship was slightly curvilinear, there was no indication of a limited capacity for zinc retention with high doses. However, doses above 4 mumol resulted in higher turnover rates in rats accustomed to lower zinc intakes. Percent retention and the reciprocal of the turnover rate were proportional to the reciprocal of the dietary zinc concentration. The greatest differences in retention and turnover occurred between 12 and 26 mg Zn/kg diet. The zinc dose in a meal and the usual dietary zinc separately influenced percent zinc retention. These factors also interacted, such that greater dose effects were observed at lower zinc intakes and greater dietary zinc effects were observed at lower doses

Stable High-Capacity Lithium Ion Battery Anodes Produced by Supersonic Spray Deposition of Hematite Nanoparticles and Self-Healing Reduced Graphene Oxide

International Nuclear Information System (INIS)

Lee, Jong-Gun; Joshi, Bhavana N.; Lee, Jong-Hyuk; Kim, Tae-Gun; Kim, Do-Yeon; Al-Deyab, Salem S.; Seong, Il Won; Swihart, Mark T.; Yoon, Woo Young; Yoon, Sam S.

2017-01-01

Hematite (Fe 2 O 3 ) nanoparticles and reduced graphene oxide (rGO) were supersonically sprayed onto copper current collectors to create high-performance, binder-free lithium ion battery (LIB) electrodes. Supersonic spray deposition is rapid, low-cost, and suitable for large-scale production. Supersonic impact of rGO sheets and Fe 2 O 3 nanoparticles on the substrate produces compacted nanocomposite films with short diffusion lengths for Li + ions. This structure produces high reversible capacity and markedly improved capacity retention over many cycles. Decomposition of lithium oxide generated during cycling activates the solid electrolyte interface layer, contributing to high capacity retention. The optimal composition ratio of rGO to Fe 2 O 3 was 9.1 wt.%, which produced a reversible capacity of 1242 mAh g −1 after N = 305 cycles at a current density of 1000 mA g −1 (1C).

Biochar effects on wet and dry regions of the soil water retention curve of a sandy loam

DEFF Research Database (Denmark)

Arthur, Emmanuel; Moldrup, Per; Sun, Zhencai

2014-01-01

Reported beneficial effects of biochar on soil physical properties and processes include decreased soil density, and increased soil water transport, water holding capacity and retention (mainly for the wet region). Research is limited on biochar effects on the full soil water retention curve (wet...... and dry regions) for a given soil and biochar amendment scenarios. This study evaluates how biochar applied to a sandy loam field at rates from 0 to 50 Mg ha−1 yr–1 in 2011, 2012, or both years (2011+2012) influences the full water retention curve. Inorganic fertilizer and pig slurry were added to all...... treatments. Six months after the last biochar application, intact and disturbed soil samples were collected for analyses. Soil water retention was measured from −1 kPa to −100 kPa using tension tables and ceramic plates and from −10 MPa to −480 MPa using a Vapor Sorption Analyzer. Soil specific area...

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.)

Testing plan for critical heat flux measurement during in-vessel retention

International Nuclear Information System (INIS)

Aoki, Kazuyoshi; Iwaki, Chikako; Sato, Hisaki; Mimura, Satoshi; Kanamori, Daisuke

2015-01-01

In-Vessel Retention (IVR) is a method to maintain molten debris in a reactor vessel (RV) by RV outer surface cooling. Structural integrity of RV and cooling capacity on RV outer surface are important to verify IVR strategy. Critical Heat Flux (CHF) data is necessary to estimate cooling capacity on the RV outer surface. And there are some CHF data to estimate cooling capacity on the RV outer surface. However, these data were obtained for specific plants. Thus, the objective of this study is developing a CHF correlation for various PWR plants. The objectives of this paper are developing test equipment and testing plan for the CHF correlation. Firstly, plant conditions during severe accidents were organized. Then, ranges of testing parameters were estimated with the plant conditions. And specifications of the test equipment were set to cover the range of parameters. Secondly, testing cases were set based on design of experiments. The test cases are suitable to develop experimental correlations. (author)

Encapsulation of vitamin E: effect of physicochemical properties of wall material on retention and stability.

Science.gov (United States)

Hategekimana, Joseph; Masamba, Kingsley George; Ma, Jianguo; Zhong, Fang

2015-06-25

Spray drying technique was used to fabricate Vitamin E loaded nanocapsules using Octenyl Succinic Anhydride (OSA) modified starches as emulsifiers and wall materials. Several physicochemical properties of modified starches that are expected to influence emulsification capacity, retention and storage stability of Vitamin E in nanocapsules were investigated. High Degree of Substitution (DS), low Molecular Weight (Mw) and low interfacial tension improved emulsification properties while Oxygen Permeability (OP) and Water Vapor Permeability (WVP) affected the film forming properties. The degradation profile of Vitamin E fitted well with the Weibull model. Nanocapsules from OSA modified starches MS-A and MS-B retained around 50% of Vitamin E after a period of 60 days at 4-35°C. Reduced retention and short half-life (35 days) in nanocapsules fabricated using MS-C at 35°C were attributed to autoxidation reaction occurred due to poor film forming capacity. These results indicated that low molecular weights OSA modified starches were effective at forming stable Vitamin E nanocapsules that could be used in drug and beverage applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of thermal treatment on bentonite used as adsorbent for Cd, Pb, Zn retention from mono-solute and poly-solute aqueous solutions

Directory of Open Access Journals (Sweden)

Susana Yamila Martinez Stagnaro

2012-08-01

Full Text Available The retentions of Zn, Cd and Pb cations by one treated bentonite up to 750 °C were analyzed. The retentions were evaluated by using mono-and poly-solute aqueous solutions of such cations. The adsorptions were carried out in batch system at room temperature. The solid/liquid ratio was 2% wt.v-1. The solids were characterized by X-ray diffraction, thermal and chemical analyses. The Zn cation from mono- or polysolute-solutions was retained in higher amount than Cd and Pb cations in similar solution types by bentonite. The retentions were effective up to 450 °C calcined bentonite, after that, the retention capacity decreased in concordance with dehydroxylation of the structure of clay minerals.

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.

Effects of mineral additives on biochar formation: carbon retention, stability, and properties.

Science.gov (United States)

Li, Feiyue; Cao, Xinde; Zhao, Ling; Wang, Jianfei; Ding, Zhenliang

2014-10-07

Biochar is being recognized as a promising tool for long-term carbon sequestration, and biochar with high carbon retention and strong stability is supposed to be explored for that purpose. In this study, three minerals, including kaolin, calcite (CaCO3), and calcium dihydrogen phosphate [Ca(H2PO4)2], were added to rice straw feedstock at the ratio of 20% (w/w) for biochar formation through pyrolysis treatment, aiming to improve carbon retention and stabilization in biochar. Kaolin and CaCO3 had little effect on the carbon retention, whereas Ca(H2PO4)2 increased the carbon retention by up to 29% compared to untreated biochar. Although the carbon loss from the kaolin-modified biochar with hydrogen peroxide oxidation was enhanced, CaCO3 and Ca(H2PO4)2 modification reduced the carbon loss by 18.6 and 58.5%, respectively. Moreover, all three minerals reduced carbon loss of biochar with potassium dichromate oxidation from 0.3 to 38.8%. The microbial mineralization as CO2 emission in all three modified biochars was reduced by 22.2-88.7% under aerobic incubation and 5-61% under anaerobic incubation. Enhanced carbon retention and stability of biochar with mineral treatment might be caused by the enhanced formation of aromatic C, which was evidenced by cross-polarization magic angle spinning (13)C nuclear magnetic resonance spectra and Fourier transform infrared spectroscopy analysis. Our results indicated that the three minerals, especially Ca(H2PO4)2, were effective in increasing carbon retention and strengthening biochar stabilization, which provided a novel idea that people could explore and produce the designated biochar with high carbon sequestration capacity and stability.

Assessment of metal retention in newly constructed highway embankments.

Science.gov (United States)

Werkenthin, Moritz; Kluge, Björn; Wessolek, Gerd

2016-12-01

Newly constructed embankments should provide both a specific bearing capacity to enable trafficability in emergency cases and a sufficient pollutant retention capacity to protect the groundwater. A number of lysimeters were installed along the A115 highway to determine total and dissolved metal concentrations in road runoff and in the soil solution of newly constructed embankments. Dissolved concentrations in soil solution of the embankments did not exceed the trigger values of the German legislation. Depending on the metal, total concentrations in soil solution were more than twice as high as dissolved concentrations. The high infiltration rates lead to increased groundwater recharge beneath the embankments (up to 4100 mm a -1 ). Although metal concentrations were not problematic from the legislators' point of view, the elevated infiltration rates beside the road facilitated the transfer of high metal loads into deeper soil layers and potentially into the groundwater as well.

Effects of different N sources on riverine DIN export and retention in subtropical high-standing island, Taiwan

Science.gov (United States)

Huang, J.-C.; Lee, T.-Y.; Lin, T.-C.; Hein, T.; Lee, L.-C.; Shih, Y.-T.; Kao, S.-J.; Shiah, F.-K.; Lin, N.-H.

2015-10-01

Increases in nitrogen (N) availability and mobility resulting from anthropogenic activities has substantially altered N cycle both locally and globally. Taiwan characterized by the subtropical montane landscape with abundant rainfall, downwind to the most rapidly industrializing east coast of China can be a demonstration site for extreme high N input and riverine DIN (dissolved inorganic N) export. We used 49 watersheds classified into low-, moderate-, and highly-disturbed categories based on population density to illustrate their differences in nitrogen inputs through atmospheric N deposition, synthetic fertilizers and human emission and DIN export ratios. Our results showed that the island-wide average riverine DIN export is ~ 3800 kg N km-2 yr-1, approximately 18-fold higher than the global average mostly due to the large input of synthetic fertilizers. The average riverine DIN export ratio is 0.30-0.51, which is much higher than the average of 0.20-0.25 of large rivers around the world indicating excessive N input relative to ecosystem demand or retention capacity. The low-disturbed watersheds, despite of high N input, only export 0.06-0.18 of the input so were well buffered to changes in input quantity suggesting high efficiency of nitrogen usage or high N retention capacity of the less disturbed watersheds. The high retention capacity probably is due to the effective uptake by secondary forests in the watersheds. The moderate-disturbed watersheds show a linear increase of output with increases in total N inputs and a mean DIN export ratio of 0.20 to 0.31. The main difference in land use between low and moderately disturbed watershed is the relative proportions of agricultural land and forests, not the built-up lands. Thus, their greater DIN export quantity could be attributed to N fertilizers used in the agricultural lands. The greater export ratios also imply that agricultural lands have lower proportional N retention capacity and that reforestation could be

Plasma wall interaction and tritium retention in TFTR

International Nuclear Information System (INIS)

Skinner, C.H.; Amarescu, E.; Ascione, G.

1996-01-01

The Tokamak Fusion Test Reactor (TFTR) has been operating safely and routinely with deuterium-tritium fuel for more than two years. In this time, TFTR has produced an impressive number of record breaking results including core fusion power, ∼ 2 MW/m 3 , comparable to that expected for ITER. Advances in wall conditioning via lithium pellet injection have played an essential role in achieving these results. Deuterium-tritium operation has also provided a special opportunity to address the issues of tritium recycling and retention. Tritium retention over two years of operation was approximately 40%. Recently, the in-torus tritium inventory was reduced by half through a combination of glow discharge cleaning, moist-air soaks, and plasma discharge cleaning. The tritium inventory is not a constraint in continued operations. The authors present recent results from TFTR in the context of plasma wall interactions and deuterium-tritium issues

Plasma wall interaction and tritium retention in TFTR

International Nuclear Information System (INIS)

Skinner, C.H.; Amarescu, E.; Ascione, G.

1997-01-01

The Tokamak Fusion Test Reactor (TFTR) has been operating safely and routinely with deuterium-tritium fuel for more than two years. In this time, TFTR has produced a number of record breaking results including core fusion power, ∝2 MW/m 3 , comparable to that expected for ITER. Advances in wall conditioning via lithium pellet injection have played an essential role in achieving these results. Deuterium-tritium operation has also provided a special opportunity to address the issues of tritium recycling and retention. Tritium retention over two years of operation was approximately 40%. Recently the in-torus tritium inventory was reduced by half through a combination of glow discharge cleaning, moist-air soaks, and plasma discharge cleaning. The tritium inventory is not a constraint in continued operations. Recent results from TFTR in the context of plasma wall interactions and deuterium-tritium issues are presented. (orig.)

Midwifery capacity building in Papua New Guinea: Key achievements and ways forward.

Science.gov (United States)

Dawson, Angela; Kililo, Mary; Geita, Lahui; Mola, Glen; Brodie, Pat M; Rumsey, Michele; Copeland, Felicity; Neill, Amanda; Homer, Caroline S E

2016-04-01

Papua New Guinea has some of the poorest health outcomes in the Asia-Pacific region. Maternal mortality is unacceptably high and there is a severe midwifery shortage requiring a quadrupling of the workforce. This paper outlines the findings of an evaluation of the Maternal Child Health Initiative (MCHI) (2012-2013) to determine key factors contributing to maternal health workforce strengthening. A descriptive mixed methods study was undertaken. Data were gathered through interviews, focus group discussions and surveys with clinicians, midwifery students and staff from nursing and midwifery schools and National Department of Health staff. Documentation from stakeholder meetings and regular site reports were reviewed. Each data set was analysed separately and meta-inferences were drawn across all data. Learning opportunities were found to have increased for midwifery educators and improvements were described in midwifery educators teaching capacity and student clinical education experience. There was an increase in the number of midwifery graduates and improvements were noted in the working environment and skills of clinical staff. Education challenges were described including the lack of clinical preceptoring and limited continuing education for clinical educators. Participants recommended increasing clinical education hours and extending the length of the midwifery program. Ongoing efforts to accredit the midwifery curricula and regulate midwifery graduates were noted. The MCHI has contributed to strengthening the midwifery workforce nationally. However, scaling-up and sustaining these achievements requires leadership and funding commitments from the midwifery schools and government alongside the accreditation of midwifery curricula and regulation of new graduates. Copyright © 2015 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Using a Complexity-Based Perspective to Better Understand the Relationships among Mentoring, School Conflicts, and Novice Retention

Science.gov (United States)

Waterman, Sheryn Elaine Spencer

2011-01-01

In this study I used complexity-thinking, ecologically-based sustainable capacity-building, narrative methodology, and pragmatism to explore the relationships among mentoring, conflict, and novice retention. In order to explore these relationships, I constructed stories from my interviews with six mentor-novice dyads in a southeastern 9-12 high…

THE IMPACT OF BENEFITS AND SERVICES ON MANAGER ENGAGEMENT AND MANAGER RETENTION IN TOURISM INDUSTRY: ENHANCED BY THE EFFECT OF MANAGEMENT LEVEL

OpenAIRE

ALDATMAZ, Ipek; AYKAÇ, Cansu; DICLE, Ülkü

2016-01-01

Manager engagement and retention are vital to the success and organizational performance of manyservice sector organisations. Maintaining manager retention is a major challenge that many hotelenterprises face today. It is critical that organizations give greater importance to manager engagement,motivation and retention and therefore establish an efficient benefits and services strategy for retainingthese core managers for the persistence and achievement of the organization. Employee motivatio...

Novel biochar-impregnated calcium alginate beads with improved water holding and nutrient retention properties.

Science.gov (United States)

Wang, Bing; Gao, Bin; Zimmerman, Andrew R; Zheng, Yulin; Lyu, Honghong

2018-03-01

Drought conditions and nutrients loss have serious impacts on soil quality as well as crop yields in agroecosystems. New techniques are needed to carry out effective soil water and nutrient conservation and fertilizer application tools. Here, calcium alginate (CA) beads impregnated with ball-milled biochar (BMB) were investigated as a new type of water/nutrients retention agent. Both CA and Ca-alginate/ball milled biochar composite (CA-BMB) beads showed high kinetic swelling ratios in KNO 3 solution and low kinetic swelling ratios in water, indicating that CA-BMB beads have the potential to retain mineral nitrogen and nutrients by ion exchange. Pseudo-second-order kinetic model well-described the swelling kinetics of both beads in KNO 3 solution. Over a range of temperatures, the characteristics of dehydration suggested that impregnation with BMB improved the water holding capacity and postponed the dehydration time of Ca-alginate. The cumulative swelling and release characteristics of water, K + , and NO 3 - indicated that CA-BMB beads have great potential as a soil amendment to improve its nutrient retention and water holding capacity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Plant-available soil water capacity: estimation methods and implications

Directory of Open Access Journals (Sweden)

Bruno Montoani Silva

2014-04-01

Full Text Available The plant-available water capacity of the soil is defined as the water content between field capacity and wilting point, and has wide practical application in planning the land use. In a representative profile of the Cerrado Oxisol, methods for estimating the wilting point were studied and compared, using a WP4-T psychrometer and Richards chamber for undisturbed and disturbed samples. In addition, the field capacity was estimated by the water content at 6, 10, 33 kPa and by the inflection point of the water retention curve, calculated by the van Genuchten and cubic polynomial models. We found that the field capacity moisture determined at the inflection point was higher than by the other methods, and that even at the inflection point the estimates differed, according to the model used. By the WP4-T psychrometer, the water content was significantly lower found the estimate of the permanent wilting point. We concluded that the estimation of the available water holding capacity is markedly influenced by the estimation methods, which has to be taken into consideration because of the practical importance of this parameter.

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.

The role of postural control in the association between aerobic capacity and walking capacity in chronic stroke: a cross-sectional analysis.

Science.gov (United States)

Outermans, Jacqueline C; van de Port, Ingrid; Kwakkel, Gert; Visser-Meily, Johanna M; Wittink, Harriet

2018-03-12

Reports on the association between aerobic capacity and walking capacity in people after stroke show disparate results. To determine (1) if the predictive validity of peak oxygen uptake (VO2peak) for walking capacity post stroke is different from that of maximal oxygen uptake (VO2max) and (2) if postural control, hemiplegic lower extremity muscle strength, age and gender distort the association between aerobic capacity and walking capacity. Cross-sectional study. General community in Utrecht, the Netherlands. Community-dwelling people more than three months after stroke. Measurement of aerobic capacity were performed with cardiopulmonary exercise testing (CPET) and differentiated between the achievement of VO2peak or VO2max. Measurement of walking capacity with the Six Minute Walk Test (6MWT), postural control with the Performance Oriented Mobility Assessment (POMA) and hemiplegic lower extremity muscle strength with the Motricity Index (MI-LE). Fifty-one out of 62 eligible participants, aged 64.7 (±12.5) years were included. Analysis of covariance (ANCOVA) showed a nonsignificant difference between the predictive validities of VO2max (N = 22, β = 0.56; 95%CI 0.12 - 0.97) and VO2peak (N = 29, β = 0.72; 95%CI 0.38 - 0.92). Multiple regression analysis of the pooled sample showed a significant decrease in the β value of VO2peak (21.6%) for the 6MWT when adding the POMA as a covariate in the association model. VO2peak remained significantly related to 6MWT after correcting for the POMA (β = 0.56 (95%CI 0.39 - 0.75)) CONCLUSIONS: The results suggest similar predictive validity of aerobic capacity for walking capacity in participants achieving VO2max compared to those only achieving VO2peak. Postural control confounds the association between aerobic capacity and walking capacity. Aerobic capacity remains a valid predictor of walking capacity. Aerobic capacity is an important factor associated with walking capacity after stroke. However, to understand this

Emporium Model: The Key to Content Retention in Secondary Math Courses

Directory of Open Access Journals (Sweden)

Sandra Wilder

2016-07-01

Full Text Available The math emporium model was first developed by Virginia Tech in 1999. In the emporium model students use computer-based learning resources, engage in active learning, and work toward mastery of concepts. This approach to teaching and learning mathematics was piloted in a rural STEM high school. The purpose of this experimental study was to compare the impact of the emporium model and the traditional approach to instruction on student achievement and retention of algebra. The results indicated that both approaches to instruction were equally effective in improving student mathematics knowledge. However, the findings revealed that the students in the emporium section had significantly higher retention of the content knowledge.

The effects of changes to estuarine hydrology on system phosphorous retention capacity: The Mondego estuary, Portugal

DEFF Research Database (Denmark)

Lillebo, A. I.; Otero, M.; Coelho, J. P.

2012-01-01

with the highest PO4-P adsorption capacity (Q* = 657 mu g P g(-1) wwt), thus the PO4-P availability in the water column was mostly dependent on the mineralization processes, which is in agreement with previous findings; ii) After 1998, the water residence time diminished from moderate (weeks) to short (days......). This change coincided with a diversion of the water to an area with a much lower PO4-P adsorption capacity (Q* = 410 mu g P g(-1) wwt), which represented a decrease in 7.3% of the system adsorption capacity. This means that sediments were not able to adsorb much of the PO4-P and a higher equilibrium...... in the estuary, we framed the hypothesis that the significant increase of DIP could be related to different sorption capacities of the sediments. The results highlighted two scenarios: i) Before 1998 the nutrient-rich freshwater input from the upstream cultivated lands entered the system through the area...

Evaluation and capacity building to improve precollege science and mathematics achievement in the US: 10 CFR, Part 605. Technical progress report, June--December 1992

Energy Technology Data Exchange (ETDEWEB)

1992-12-31

The National Center for Improving Science Education has undertaken activities to achieve evaluation goals for DOE`s Precollege programs: develop means to determine program quality; develop means for determining the contribution of DOE precollege programs to both teacher enhancement and student achievement; provide evaluation designs and instruments and reports of program quality and impact; and strengthen both DOE`s and the Labs` capacity to do both short- and long-term planning as well as deliver effective programs and evaluation. Appendices include evaluation/technical assistance report, profiling teacher research participation and teacher development programs, teacher surveys, impact assessment design, and teacher research participation programs anecdotes for 8 labs.

Recent developments in nanostructured inorganic materials for sorption of cesium and strontium: Synthesis and shaping, sorption capacity, mechanisms, and selectivity-A review.

Science.gov (United States)

Alby, Delhia; Charnay, Clarence; Heran, Marc; Prelot, Bénédicte; Zajac, Jerzy

2018-02-15

Liquid wastes containing non-ferrous heavy metal ions and some radionuclides, 137 Cs and 90 Sr in particular, represent one of the most dangerous sources of environmental contamination. The remediation of wastewater containing such pollutants continue to be among the biggest challenges of Sustainable Development and Environmental Safety. Sorption-based technologies have proven their efficiency also in reducing the radionuclide content in aqueous streams to low-level residual activity, with the concomitant decrease in the amount of ultimate solid waste generated. Although sorption of cesium and strontium by resins, clays, and zeolites has been investigated intensively and even used in real applications, there is still considerable scope for improvement in terms of retention capacity and selectivity. Recent progress in design and preparation of nanostructured inorganic materials has attracted growing interest based on the potential for improving the retention performance when coupling such functionalities as ion exchange capacity, structural flexibility that may result in steric retention effects, as well as the propensity to interact specifically with the target metal cations. Titanate, vanadate, and tungsten based materials, manganese oxides, hexacyanoferrates, metal sulfides, ammonium molybdophosphates, or hydroxyapatite, characterized by various structures and morphologies, are reviewed with the emphasis being put on synthesis and shaping of such materials, their structure in relationship with the capacity and selectivity of trapping cesium and strontium from either single or multi-component aqueous solutions, as well as the possible retention mechanism. The potential candidates for remediation uses are selected with regard to their sorption capacity and distribution coefficient towards target cations, and also the pH window for an optimum cation capture. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Soil retention of hexavalent chromium released from construction and demolition waste in a road-base-application scenario.

Science.gov (United States)

Butera, Stefania; Trapp, Stefan; Astrup, Thomas F; Christensen, Thomas H

2015-11-15

We investigated the retention of Cr(VI) in three subsoils with low organic matter content in laboratory experiments at concentration levels relevant to represent leachates from construction and demolition waste (C&DW) reused as unbound material in road construction. The retention mechanism appeared to be reduction and subsequent precipitation as Cr(III) on the soil. The reduction process was slow and in several experiments it was still proceeding at the end of the six-month experimental period. The overall retention reaction fit well with a second-order reaction governed by actual Cr(VI) concentration and reduction capacity of the soil. The experimentally determined reduction capacities and second-order kinetic parameters were used to model, for a 100-year period, the one-dimensional migration of Cr(VI) in the subsoil under a layer of C&DW. The resulting Cr(VI) concentration would be negligible below 7-70 cm depth. However, in rigid climates and with high water infiltration through the road pavement, the reduction reaction could be so slow that Cr(VI) might migrate as deep as 200 cm under the road. The reaction parameters and the model can form the basis for systematically assessing under which scenarios Cr(VI) from C&DW could lead to an environmental issue for ground- and receiving surface waters. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Adsorption properties of the soils of the Ranger uranium mine land application area for solutes in water from Retention Pond 2

International Nuclear Information System (INIS)

Willett, I.R.; Bond, W.J.

1992-01-01

The research reported here aimed to describe the adsorption properties of the soils of Ranger's irrigation area for important constituents of RP2 water. Three kinds of experiments were conducted. For the major ions (Na + , Mg 2+ , Ca 2+ , K + , SO 4 2-, and Cl - ) measurements were made of cation and anion exchange capacities. For the minor solutes (MN 2+ , U 238 , and Ra 226 ) which undergo more specific, inner-sphere reactions with soil surfaces, the retention capacities were determined by batch adsorption isotherm methods. Lastly, column experiments were conducted to determine whether the soils could retain U 238 , Ra 226 and Pb 210 when the quantities of each radionuclide were applied in much greater quantities than was possible in the batch adsorption studies, or during the field experiment described earlier at this Workshop (Bond and Willett 1992). It was aimed to obtain information on the retention capacity of the three main soil types of the irrigation area; Unit I, II and III, respectively red earths, yellow earths and siliceous sands, in relation to soil pH. 7 refs., 4 tabs., 13 figs

Hydrological performance of dual-substrate-layer green roofs using porous inert substrates with high sorption capacities.

Science.gov (United States)

Wang, Xiaoou; Tian, Yimei; Zhao, Xinhua; Peng, Chenrui

2017-06-01

Given that the common medium in existing green roofs is a single layer composed of organic and inorganic substrates, seven pilot-scale dual-substrate-layer extensive green roofs (G1-G7), which include nutrition and adsorption substrate layers, were constructed in this study. The effectiveness of porous inert substrates (activated charcoal, zeolite, pumice, lava, vermiculite and expanded perlite) used as the adsorption substrate for stormwater retention was investigated. A single-substrate-layer green roof (G8) was built for comparison with G1-G7. Despite the larger total rainfall depth (mm) of six types of simulated rains (43.2, 54.6, 76.2, 87.0, 85.2 and 86.4, respectively), the total percent retention of G1-G7 varied between 14% and 82% with an average of 43%, exhibiting better runoff-retaining capacity than G8 based on the maximum potential rainfall storage depth per unit height of adsorption substrate. Regression analysis showed that there was a logarithmic relationship between cumulative rainfall depth with non-zero runoff and stormwater retention for G1-G4 and a linear relationship for G5-G8. To enhance the water retention capacity and extend the service life of dual-substrate-layer extensive green roofs, the mixture of activated charcoal and/or pumice with expanded perlite and/or vermiculite is more suitable as the adsorption substrate than the mixture containing lava and/or zeolite.

Quantitative structure-retention relationships of pesticides in reversed-phase high-performance liquid chromatography

International Nuclear Information System (INIS)

Aschi, Massimiliano; D'Archivio, Angelo Antonio; Maggi, Maria Anna; Mazzeo, Pietro; Ruggieri, Fabrizio

2007-01-01

In this paper, a quantitative structure-retention relationships (QSRR) method is employed to predict the retention behaviour of pesticides in reversed-phase high-performance liquid chromatography (HPLC). A six-parameter nonlinear model is developed by means of a feed-forward artificial neural network (ANN) with back-propagation learning rule. Accurate description of the retention factors of 26 compounds including commonly used insecticides, herbicides and fungicides and some metabolites is successfully achieved. In addition to the acetonitrile content, included to describe composition of the water-acetonitrile mobile phase, the octanol-water partition coefficient (from literature) and four quantum chemical descriptors are considered to account for the effect of solute structure on the retention. These are: the total dipole moment, the mean polarizability, the anisotropy of polarizability and a descriptor of hydrogen bonding ability based on the atomic charges on hydrogen bond donor and acceptor chemical functionalities. The proposed nonlinear QSRR model exhibits a high degree of correlation between observed and computed retention factors and a good predictive performance in wide range of mobile phase composition (40-65%, v/v acetonitrile) that supports its application for the prediction of the chromatographic behaviour of unknown pesticides. A multilinear regression model based on the same six descriptors shows a significantly worse predictive capability

Quantitative structure-retention relationships of pesticides in reversed-phase high-performance liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Aschi, Massimiliano [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); D' Archivio, Angelo Antonio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)]. E-mail: darchivi@univaq.it; Maggi, Maria Anna [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Mazzeo, Pietro [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Ruggieri, Fabrizio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)

2007-01-23

In this paper, a quantitative structure-retention relationships (QSRR) method is employed to predict the retention behaviour of pesticides in reversed-phase high-performance liquid chromatography (HPLC). A six-parameter nonlinear model is developed by means of a feed-forward artificial neural network (ANN) with back-propagation learning rule. Accurate description of the retention factors of 26 compounds including commonly used insecticides, herbicides and fungicides and some metabolites is successfully achieved. In addition to the acetonitrile content, included to describe composition of the water-acetonitrile mobile phase, the octanol-water partition coefficient (from literature) and four quantum chemical descriptors are considered to account for the effect of solute structure on the retention. These are: the total dipole moment, the mean polarizability, the anisotropy of polarizability and a descriptor of hydrogen bonding ability based on the atomic charges on hydrogen bond donor and acceptor chemical functionalities. The proposed nonlinear QSRR model exhibits a high degree of correlation between observed and computed retention factors and a good predictive performance in wide range of mobile phase composition (40-65%, v/v acetonitrile) that supports its application for the prediction of the chromatographic behaviour of unknown pesticides. A multilinear regression model based on the same six descriptors shows a significantly worse predictive capability.

Identifying, Monitoring, and Benchmarking Teacher Retention and Turnover: Guidelines for TIF Grantees

Science.gov (United States)

Finster, Matthew

2015-01-01

Having a well-qualified, effective teacher in every classroom is a cornerstone of current educational reforms. Clearly, retaining these effective teachers is critical to achieving this goal. This brief presents a strategic accountability approach to managing teacher talent retention and turnover. The brief begins with an overview of a strategic…

Improved positive electrode materials for lithium-ion batteries: Exploring the high specific capacity of lithium cobalt dioxide and the high rate capability of lithium iron phosphate

Science.gov (United States)

Chen, Zhaohui

During the past decade, the search for better electrode materials for Li-ion batteries has been of a great commercial interest, especially since Li-ion technology has become a major rechargeable battery technology with a market value of $3 billion US dollars per year. This thesis focuses on improving two positive electrode materials: one is a traditional positive electrode material--LiCoO2; the other is a new positive electrode material--LiFePO 4. Cho et al. reported that coating LiCoO2 with oxides can improve the capacity retention of LiCoO2 cycled to 4.4 V. The study of coatings in this thesis confirms this effect and shows that further improvement (30% higher energy density than that used in a commercial cell with excellent capacity retention) can be obtained. An in-situ XRD study proves that the mechanism of the improvement in capacity retention by coating proposed by Cho et al. is incorrect. Further experiments identify the suppression of impedance growth in the cell as the key reason for the improvement caused by coating. Based on this, other methods to improve the energy density of LiCoO2, without sacrificing capacity retention, are also developed. Using an XRD study, the structure of the phase between the O3-phase Li 1-xCoO2 (x > 0.5) and the O1 phase CoO2 was measured experimentally for the first time. XRD results confirmed the prediction of an H1-3 phase by Ceder's group. Apparently, because of the structural changes between the O3 phase and the H1-3 phase, good capacity retention cannot be attained for cycling LiCoO2 to 4.6 V with respect to Li metal. An effort was also made to reduce the carbon content in a LiFePO 4/C composite without sacrificing its rate capability. It was found that about 3% carbon by weight maintains both a good rate capability and a high pellet density for the composite.

Striving for Excellence Sometimes Hinders High Achievers: Performance-Approach Goals Deplete Arithmetical Performance in Students with High Working Memory Capacity

Science.gov (United States)

Crouzevialle, Marie; Smeding, Annique; Butera, Fabrizio

2015-01-01

We tested whether the goal to attain normative superiority over other students, referred to as performance-approach goals, is particularly distractive for high-Working Memory Capacity (WMC) students—that is, those who are used to being high achievers. Indeed, WMC is positively related to high-order cognitive performance and academic success, a record of success that confers benefits on high-WMC as compared to low-WMC students. We tested whether such benefits may turn out to be a burden under performance-approach goal pursuit. Indeed, for high achievers, aiming to rise above others may represent an opportunity to reaffirm their positive status—a stake susceptible to trigger disruptive outcome concerns that interfere with task processing. Results revealed that with performance-approach goals—as compared to goals with no emphasis on social comparison—the higher the students’ WMC, the lower their performance at a complex arithmetic task (Experiment 1). Crucially, this pattern appeared to be driven by uncertainty regarding the chances to outclass others (Experiment 2). Moreover, an accessibility measure suggested the mediational role played by status-related concerns in the observed disruption of performance. We discuss why high-stake situations can paradoxically lead high-achievers to sub-optimally perform when high-order cognitive performance is at play. PMID:26407097

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.

Short-Run Effects of Parental Job Loss on Children's Academic Achievement. NBER Working Paper No. 15480

Science.gov (United States)

Stevens, Ann Huff; Schaller, Jessamyn

2009-01-01

We study the relationship between parental job loss and children's academic achievement using data on job loss and grade retention from the 1996, 2001, and 2004 panels of the Survey of Income and Program Participation. We find that a parental job loss increases the probability of children's grade retention by 0.8 percentage points, or around 15…

Porous one-dimensional carbon/iron oxide composite for rechargeable lithium-ion batteries with high and stable capacity

International Nuclear Information System (INIS)

Zhu, Jiadeng; Lu, Yao; Chen, Chen; Ge, Yeqian; Jasper, Samuel; Leary, Jennifer D.; Li, Dawei; Jiang, Mengjin; Zhang, Xiangwu

2016-01-01

Hematite iron oxide (α-Fe_2O_3) is considered to be a prospective anode material for lithium-ion batteries (LIBs) because of its high theoretical capacity (1007 mAh g"−"1), nontoxicity, and low cost. However, the low electrical conductivity and large volume change during Li insertion/extraction of α-Fe_2O_3 hinder its use in practical batteries. In this study, carbon-coated α-Fe_2O_3 nanofibers, prepared via an electrospinning method followed by a thermal treatment process, are employed as the anode material for LIBs. The as-prepared porous nanofibers with a carbon content of 12.5 wt% show improved cycling performance and rate capability. They can still deliver a high and stable capacity of 715 mAh g"−"1 even at superior high current density of 1000 mA g"−"1 after 200 cycles with a large Coulombic efficiency of 99.2%. Such improved electrochemical performance can be assigned to their unique porous fabric structure as well as the conductive carbon coating which shorten the distance for Li ion transport, enhancing Li ion reversibility and kinetic properties. It is, therefore, demonstrated that carbon-coated α-Fe_2O_3 nanofiber prepared under optimized conditions is a promising anode material candidate for LIBs. - Graphical abstract: Carbon-coated α-Fe_2O_3 nanofibers are employed as anode material to achieve high and stable electrochemical performance for lithium-ion batteries, enhancing their commercial viability. - Highlights: • α-Fe_2O_3/C nanofibers were fabricated by electrospinning and thermal treatment. • α-Fe_2O_3/C nanofibers exhibit stable cyclability and good rate capability. • α-Fe_2O_3–C nanofibers maintain high capacity at 1000 mA g"−"1 for 200 cycles. • A capacity retention of 99.2% is achieved by α-Fe_2O_3–C nanofibers after 200 cycles.

Quartz exposure, retention, and early silicosis in sheep.

Science.gov (United States)

Bégin, R; Dufresne, A; Cantin, A; Possmayer, F; Sébastien, P; Fabi, D; Bilodeau, G; Martel, M; Bisson, D; Pietrowski, B

1989-05-01

The purposes of this study were (1) to investigate the chronology of events in cellular and biochemical changes thought to be important in the development of silicosis, (2) to relate these to changes in lung function and radiograph, and (3) to evaluate the relation of quartz exposure and retention to individual response leading to early silicosis. Thirty-six sheep were exposed by repeated intratracheal infusion at 10-day intervals to 100 mg Minusil-5 in 100 ml saline (Si group), and 10 sheep were exposed at the same intervals to 100 ml saline (control). All sheep were investigated at 3-month intervals by chest radiograph, lung function, and lung lavage. At month 9, chest radiograph score of parenchymal opacities was significantly increased at 2.8 +/- 0.6 versus 0.4 +/- 0.4 in the Si group (p less than .05), establishing early radiologic silicosis. Lung function was significantly altered with reduction in lung compliance, vital capacity, and diffusion capacity (p less than .05). Lung lavage cellularity revealed significant increase in total cells (X 2.5), macrophages (X3), and neutrophils (X3). Albumin in BAL remained at the control level. Fibronectin production was significantly increased, as was the fibroblast growth activity, without significant change in procollagen 3 at this early stage of disease. Total phospholipids were significantly elevated in the Si-exposed sheep, and the profile demonstrated an increase in all the phospholipid components. Spontaneous release of hydrogen peroxide by alveolar cells was not increased, but in the presence of phorbol myristate acetate (PMA) higher levels of peroxide were found in the quartz-exposed sheep (p less than .05). The cellular and biochemical alterations of lung lavage preceded other changes. At month 12, there were good correlations (r greater than .49, p less than .001) between parameters evaluating related phenomena but poor correlations between measurements evaluating different aspects of the disorder. To

Peak capacity, peak-capacity production rate, and boiling point resolution for temperature-programmed GC with very high programming rates

Science.gov (United States)

Grall; Leonard; Sacks

2000-02-01

Recent advances in column heating technology have made possible very fast linear temperature programming for high-speed gas chromatography. A fused-silica capillary column is contained in a tubular metal jacket, which is resistively heated by a precision power supply. With very rapid column heating, the rate of peak-capacity production is significantly enhanced, but the total peak capacity and the boiling-point resolution (minimum boiling-point difference required for the separation of two nonpolar compounds on a nonpolar column) are reduced relative to more conventional heating rates used with convection-oven instruments. As temperature-programming rates increase, elution temperatures also increase with the result that retention may become insignificant prior to elution. This results in inefficient utilization of the down-stream end of the column and causes a loss in the rate of peak-capacity production. The rate of peak-capacity production is increased by the use of shorter columns and higher carrier gas velocities. With high programming rates (100-600 degrees C/min), column lengths of 6-12 m and average linear carrier gas velocities in the 100-150 cm/s range are satisfactory. In this study, the rate of peak-capacity production, the total peak capacity, and the boiling point resolution are determined for C10-C28 n-alkanes using 6-18 m long columns, 50-200 cm/s average carrier gas velocities, and 60-600 degrees C/min programming rates. It was found that with a 6-meter-long, 0.25-mm i.d. column programmed at a rate of 600 degrees C/min, a maximum peak-capacity production rate of 6.1 peaks/s was obtained. A total peak capacity of about 75 peaks was produced in a 37-s long separation spanning a boiling-point range from n-C10 (174 degrees C) to n-C28 (432 degrees C).

Separation and retention of iodine

International Nuclear Information System (INIS)

Thomas, T.R.

1976-01-01

Caustic and mercuric nitrate scrubbers have been used for iodine recovery from process offgas, but they exhibit low decontamination factors for organic iodide removal and produce liquid wastes that are unsuitable for final storage. The Iodox process gives high decontamination factors for both organic iodides and elemental iodine. The liquid waste can be evaporated to a solid or concentrated and fixed in cement. Efficient separation and retention of gaseous iodine species can be obtained with silver-loaded adsorbents. The waste is a dry solid easily handled and stored. Adsorbents containing cheaper metals appear to have lower iodine-loading capacities and may be unsuitable for bulk iodine removal from process offgas because of the large amounts of solid waste that would be generated. A potential method for regenerationg and recycling silver-loaded adsorbents is being evaluated. In conjunction with the regeneration, lead-exchanged zeolite is used as a secondary adsorbent for the final fixation and storage of the iodine

Assessment of the exchange parameters of Amberlite IR-45 (OH ...

African Journals Online (AJOL)

CLEMENT O BEWAJI

The results obtained showed retention time of 33min, retention volume of ... 18cm3, and exchange capacity of 41mmole/g and exchange site density of .... This was achieved by preparing the slurry in 30cm3 distilled water in a 100cm3 beaker.

Water Retention Curves of Opalinus Clay

International Nuclear Information System (INIS)

Villar, M. V.; Romero, F. J.

2012-01-01

The water retention curve of Opalinus clay samples was determined under different conditions: total and matric suction, stress or no-stress conditions, wetting and drying paths. Through the fitting of these results to the van Genuchten expression the P parameter, related to the air entry value (AEV), was obtained. The AEV is the suction value above which air is able to enter the pores of the sample, and consequently, above which 2-phase flow can take place in the soil pore structure. The samples used in this research came from two different boreholes, BHT-1 and BHG-D1, but the behaviour of them did not depend on their location, what was probably due to the fact that both were drilled in the shay facies of the Opalinus clay. There was not a distinct difference between the results obtained under total or matric suctions. In the drying paths, both the water contents and the degrees of saturation tended to be higher when total suction was applied, however the reverse trend was observed for the water contents reached in wetting paths. As well, no clear difference was observed in the water retention curves obtained in odometers under matric and total suctions, what points to the osmotic component of suction in Opalinus clay not being significant. Overall, the water contents were lower and the degrees of saturation higher when suction was applied under vertical stress, what would indicate that the water retention capacity was lower under 8 MPa vertical stress than under free volume conditions. This vertical stress value is slightly higher than the maximum in situ stress. Also, the samples showed hysteresis according to the expected behaviour, i.e. the water contents for a given suction were higher during a drying path than during a wetting path. The P values obtained were between 6 and 34 MPa, and tended to be higher for the samples tested under stress, in drying paths and when total suction was used. The air entry value calculated from the mercury intrusion porosimetry

Water Retention Curves of Opalinus Clay

Energy Technology Data Exchange (ETDEWEB)

Villar, M. V.; Romero, F. J.

2012-11-01

The water retention curve of Opalinus clay samples was determined under different conditions: total and matric suction, stress or no-stress conditions, wetting and drying paths. Through the fitting of these results to the van Genuchten expression the P parameter, related to the air entry value (AEV), was obtained. The AEV is the suction value above which air is able to enter the pores of the sample, and consequently, above which 2-phase flow can take place in the soil pore structure. The samples used in this research came from two different boreholes, BHT-1 and BHG-D1, but the behaviour of them did not depend on their location, what was probably due to the fact that both were drilled in the shay facies of the Opalinus clay. There was not a distinct difference between the results obtained under total or matric suctions. In the drying paths, both the water contents and the degrees of saturation tended to be higher when total suction was applied, however the reverse trend was observed for the water contents reached in wetting paths. As well, no clear difference was observed in the water retention curves obtained in odometers under matric and total suctions, what points to the osmotic component of suction in Opalinus clay not being significant. Overall, the water contents were lower and the degrees of saturation higher when suction was applied under vertical stress, what would indicate that the water retention capacity was lower under 8 MPa vertical stress than under free volume conditions. This vertical stress value is slightly higher than the maximum in situ stress. Also, the samples showed hysteresis according to the expected behaviour, i.e. the water contents for a given suction were higher during a drying path than during a wetting path. The P values obtained were between 6 and 34 MPa, and tended to be higher for the samples tested under stress, in drying paths and when total suction was used. The air entry value calculated from the mercury intrusion porosimetry

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.

Improved functional capacity evaluation performance predicts successful return to work one year after completing a functional restoration rehabilitation program.

Science.gov (United States)

Fore, Lisa; Perez, Yoheli; Neblett, Randy; Asih, Sali; Mayer, Tom G; Gatchel, Robert J

2015-04-01

To evaluate whether functional capacity evaluation (FCE) scores are responsive to functional restoration treatment, and to assess the ability of FCEs at program discharge to predict work outcomes. An interdisciplinary cohort study of prospectively collected data. A functional restoration center. A consecutive sample of 354 patients with chronic disabling occupational musculoskeletal disorders (CDOMDs) completed a functional restoration program consisting of quantitatively directed exercise progression and multi-modal disability management with interdisciplinary medical supervision. Each patient participated in an FCE at admission and discharge from treatment. The results of each FCE yielded the physical demand level (PDL) at which patients were functioning. Patients were initially divided into 5 PDL groups, based on job-of-injury lifting, carrying, and pushing/pulling requirements, for the pre- to posttreatment responsiveness analyses. Patients were subsequently divided into 5 PDL groups, based on their performance on the FCE upon program completion. Outcome measures included admission-to-discharge changes in PDLs and 2 specific FCE lifting tasks: isokinetic lifting; and the Progressive Isoinertial Lifting Evaluation (PILE). Socioeconomic outcomes were also evaluated, including post-discharge work return and work retention 1-year after treatment completion. Overall, 96% of the patients demonstrated improvement in their PDLs from admission to discharge. A majority of patients (56%) were able to achieve a discharge PDL that was comparable to their estimated job-of-injury lifting requirement or higher (P work return (P work retention (P work return after treatment completion and work retention 1 year later. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Capacity Markets and Market Stability

International Nuclear Information System (INIS)

Stauffer, Hoff

2006-01-01

The good news is that market stability can be achieved through a combination of longer-term contracts, auctions for far enough in the future to permit new entry, a capacity management system, and a demand curve. The bad news is that if and when stable capacity markets are designed, the markets may seem to be relatively close to where we started - with integrated resource planning. Market ideologues will find this anathema. (author)

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

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.

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...

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.

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

Science.gov (United States)

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

2015-09-18

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

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.

Retention capacity of samarium (III) in zircon for it possible use in retaining walls for confinement of nuclear residues

International Nuclear Information System (INIS)

Garcia G, N.

2006-01-01

Mexico, as country that produces part of its electric power by nuclear means, should put special emphasis in the development of technologies guided to the sure and long term confinement of the high level nuclear residuals. This work studies the capacity that has the natural zircon to retain to the samarium (III) in solution, by what due, firstly, to characterize the zircon for technical instrumental to determine the purity and characteristic of the mineral in study. The instrumental techniques that were used to carry out the physicochemical characterization were the neutron activation analysis (NAA), the infrared spectroscopy (IS), the thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), semiquantitative analysis, dispersive energy spectroscopy (EDS), X-ray diffraction (XRD) and luminescence technique. The characterization of the surface properties carries out by means of the determination of the surface area using the BET multipoint technique, acidity constants, hydration time, the determination of the point of null charge (pH PCN ) and density of surface sites (D s ). The luminescence techniques were useful to determine the optimal point hydration of the zircon and for the quantification of the samarium, for that here intends the development of both analysis techniques. With the adjustment of the titration curves in the FITEQL 4 package the constants of surface acidity in the solid/liquid interface were determined. To the finish of this study it was corroborated that the zircon is a mineral that presents appropriate characteristics to be proposed as a contention barrier for the deep geologic confinement. With regard to the study of adsorption that one carries out the samarium retention it is superior to 90% under the described conditions. This investigation could also be applicable in the confinement of dangerous industrial residuals. (Author)

Building capacity and resilience in the dementia care workforce: a systematic review of interventions targeting worker and organizational outcomes.

Science.gov (United States)

Elliott, Kate-Ellen J; Scott, Jennifer L; Stirling, Christine; Martin, Angela J; Robinson, Andrew

2012-06-01

Dementia increasingly impacts every health and social care system in the world. Preparing the dementia care workforce is therefore paramount, particularly in light of existing problems of staff retention and turnover. Training interventions will need to increase worker and organizational capacity to deliver effective patient care. It is not clear which training interventions best enhance workers' capacity. A review of the evidence for dementia care training interventions to enhance worker capacity and facilitate organizational change is presented. A systematic literature review was conducted. All selected randomized intervention studies aimed to enhance some aspect of dementia care worker or workforce capacity such as knowledge of dementia, psychological well-being, work performance, and organizational factors such as retention or service delivery in dementia care. Seventy-four relevant studies were identified, but only six met inclusion criteria for the review. The six studies selected focused on worker and organizational outcomes in dementia care. All interventions were multi-component with dementia education or instructional training most commonly adopted. No interventions were found for the community setting. Variable effects were found for intervention outcomes and methodological concerns are raised. The rigor of scientific research in training interventions that aim to build capacity of dementia care workers is poor and a strong need exists for evaluation and delivery of such interventions in the community sphere. Wider domains of interest such as worker psychological health and well-being need to be examined further, to understand capacity-building in the dementia care workforce.

Method of Retention Control for Compromised Periodontal Bone Support Abutment of Conical Crown Retained Denture

Directory of Open Access Journals (Sweden)

Chau-Hsiang Wang

2010-08-01

Full Text Available Conical crown-retained dentures (CCRD show a higher survival rate and greater patient satisfaction than transitional removable partial dentures during long-term follow-up. However, unsustainable denture retention force on supporting abutments after initial delivery and loss retention are frequently seen in long-term follow-up of clinical cases. The main causes are insufficient information concerning denture retention designs and the retention-tolerance of the supporting abutments. Monitoring by dental technicians of the quality of dental prostheses is critical. This case report describes an optimal method for CCRD construction that determines and distributes an optimal denture retention force on the supporting abutments to allow the patient to easily remove the denture while ensuring that the CCRD remains in place during physiologic activities. Oral rehabilitation with CCRD should consider the condition of the abutment periodontal support, the interarch occlusal relationship, supplemental fatigue of the terminal abutment, and patient's estimated bite force. The effects of friction on the abutment's inner crown were based on an optimal a angle. The dental laboratory used these measurements to fabricate a CCRD using a Koni-Meter to adjust the retention of the inner crown. This method protects the abutments and reduces the wear between the inner and outer crowns. The CCRD achieved good esthetic results and physiologic functions. Periodic long-term follow-up of the patient and CCRD after initial placement is recommended.

Noncoherent capacity of secret-key agreement with public discussion

KAUST Repository

Agrawal, Anurag

2011-09-01

We study the noncoherent capacity of secret-key agreement with public discussion over independent identically distributed (i.i.d.) Rayleigh fading wireless channels, where neither the sender nor the receivers have access to instantaneous channel state information (CSI). We present two results. At high signal-to-noise ratio (SNR), the secret-key capacity is bounded in SNR, regardless of the number of antennas at each terminal. Second, for a system with a single antenna at both the legitimate and the eavesdropper terminals and an arbitrary number of transmit antennas, the secret-key capacity-achieving input distribution is discrete, with a finite number of mass points. Numerically we observe that at low SNR, the capacity achieving distribution has two mass points with one of them at the origin. © 2011 IEEE.

Noncoherent capacity of secret-key agreement with public discussion

KAUST Repository

Agrawal, Anurag; Rezki, Zouheir; Khisti, Ashish J.; Alouini, Mohamed-Slim

2011-01-01

We study the noncoherent capacity of secret-key agreement with public discussion over independent identically distributed (i.i.d.) Rayleigh fading wireless channels, where neither the sender nor the receivers have access to instantaneous channel state information (CSI). We present two results. At high signal-to-noise ratio (SNR), the secret-key capacity is bounded in SNR, regardless of the number of antennas at each terminal. Second, for a system with a single antenna at both the legitimate and the eavesdropper terminals and an arbitrary number of transmit antennas, the secret-key capacity-achieving input distribution is discrete, with a finite number of mass points. Numerically we observe that at low SNR, the capacity achieving distribution has two mass points with one of them at the origin. © 2011 IEEE.

Water retention properties of ashes; Vattenretentionsegenskaper hos aska

Energy Technology Data Exchange (ETDEWEB)

Hemstroem, Kristian; Ezziyani, Samir; Bendz, David

2009-05-15

The water holding properties of a material can be described with a water retention curve (also called pF curve or characteristic curve). The importance of this material property has until now been neglected in waste and rest products contexts. There is an eminent need for knowledge of the water holding properties of ash and rest products in order to improve the possibility to perform i) assessment of leaching from rest product used in constructions, ii) dimensioning of covers built with rest products and iii) assessment of long term properties of land fill waste concerning leaching, especially for stabilized ash with a monolithic characteristics. The aim of this project was to increase the knowledge of the water holding properties of ashes by determining water retention curves with laboratory methods on four ash materials with the potential to be used in constructions. In the project, four ashes has been studied; one MSWI bottom ash from SYSAV, one aged MSWI bottom ash from Gaerstadverket and two fly ashes from incineration of biofuels; one from SCA Ortviken and one from Jaemtkraft AB. For comparison, data from a silt soil studied in another SGI project is presented. When determining a water retention curve for a specific material water from the examined, beforehand water saturated, sample is eliminated under controlled circumstances in a pressure plate extractor. The sample is exposed to a pressure, with increasing degree, squeezing excess water out of the material. The excess water is measured for each increased pressure step and the remaining volumetric water content in the material can be calculated. The results from such measurements are presented in water retention curves, in which the volumetric water content is plotted as a function of the capillary pressure. The water retention curves shows how various materials differ in water content at the same pressure. The results from the study showed that ashes have great water holding capacity. The study also

A biomimetic high-capacity phenazine-based anolyte for aqueous organic redox flow batteries

Science.gov (United States)

Hollas, Aaron; Wei, Xiaoliang; Murugesan, Vijayakumar; Nie, Zimin; Li, Bin; Reed, David; Liu, Jun; Sprenkle, Vincent; Wang, Wei

2018-06-01

Aqueous soluble organic (ASO) redox-active materials have recently attracted significant attention as alternatives to traditional transition metal ions in redox flow batteries (RFB). However, reported reversible capacities of ASO are often substantially lower than their theoretical values based on the reported maximum solubilities. Here, we describe a phenazine-based ASO compound with an exceptionally high reversible capacity that exceeds 90% of its theoretical value. By strategically modifying the phenazine molecular structure, we demonstrate an increased solubility from near-zero with pristine phenazine to as much as 1.8 M while also shifting its redox potential by more than 400 mV. An RFB based on a phenazine derivative (7,8-dihydroxyphenazine-2-sulfonic acid) at its near-saturation concentration exhibits an operating voltage of 1.4 V with a reversible anolyte capacity of 67 Ah l-1 and a capacity retention of 99.98% per cycle over 500 cycles.

SnO2 nanoparticles anchored on vertically aligned graphene with a high rate, high capacity, and long life for lithium storage

International Nuclear Information System (INIS)

Li, Na; Sonsg, Huawei; Cui, Hao; Wang, Chengxin

2014-01-01

As a high-theoretical-capacity (782 mA hg-1), low-cost and low-toxicity material, SnO2 has attracted intense interest for use as an anode electrode for lithium-ion batteries (LIBs). Despite intensive study, the practical use of SnO2-based anodes is hindered by their poor capacity retention and low rate capacity resulting from their large specific-volume changes and kinetic limitations in ion/electron transfer during the lithium ion insertion/extraction process. Improving the performance of SnO2-based electrodes has become one of the most popular scientific and industrial efforts. Herein, we present a type of SnO2-graphene composite anode in which SnO2 nanoparticles are uniformly anchored on both sides of vertically aligned graphene nanosheets (SnO2-VAGN-SnO2). The VAGNs sandwiched by the nanoparticles can supply rapid ion and electron transport pathways for Li+ and e-. Such integrated electrodes exhibit high specific capacity and excellent cycling stability, even at high current densities. The cells can cycle more than 5,000 times and retain a reversible capacity of 210 mA h g-1 at 9 A g-1. A high current density of up to 20 A g-1 is achieved, and the power and energy density can reach 1576.75 W kg-1 and 110.14 Wh kg-1, respectively. These performances indicate that the composite could offer the advantages of both LIBs (high energy density) and supercapacitors (high power density)

Rainwater runoff retention on an aged intensive green roof.

Science.gov (United States)

Speak, A F; Rothwell, J J; Lindley, S J; Smith, C L

2013-09-01

Urban areas are characterised by large proportions of impervious surfaces which increases rainwater runoff and the potential for surface water flooding. Increased precipitation is predicted under current climate change projections, which will put further pressure on urban populations and infrastructure. Roof greening can be used within flood mitigation schemes to restore the urban hydrological balance of cities. Intensive green roofs, with their deeper substrates and higher plant biomass, are able to retain greater quantities of runoff, and there is a need for more studies on this less common type of green roof which also investigate the effect of factors such as age and vegetation composition. Runoff quantities from an aged intensive green roof in Manchester, UK, were analysed for 69 rainfall events, and compared to those on an adjacent paved roof. Average retention was 65.7% on the green roof and 33.6% on the bare roof. A comprehensive soil classification revealed the substrate, a mineral soil, to be in good general condition and also high in organic matter content which can increase the water holding capacity of soils. Large variation in the retention data made the use of predictive regression models unfeasible. This variation arose from complex interactions between Antecedant Dry Weather Period (ADWP), season, monthly weather trends, and rainfall duration, quantity and peak intensity. However, significantly lower retention was seen for high rainfall events, and in autumn, which had above average rainfall. The study period only covers one unusually wet year, so a longer study may uncover relationships to factors which can be applied to intensive roofs elsewhere. Annual rainfall retention for Manchester city centre could be increased by 2.3% by a 10% increase in intensive green roof construction. The results of this study will be of particular interest to practitioners implementing greenspace adaptation in temperate and cool maritime climates. Copyright © 2013

On the Capacity of the Intensity-Modulation Direct-Detection Optical Broadcast Channel

KAUST Repository

Chaaban, Anas

2016-01-12

The capacity of the intensity-modulation directdetection optical broadcast channel (OBC) is investigated, under both average and peak intensity constraints. An outer bound on the capacity region is derived by adapting Bergmans’ approach to the OBC. Inner bounds are derived by using superposition coding with either truncated-Gaussian (TG) distributions or discrete distributions. While the discrete distribution achieves higher rates, the TG distribution leads to a simpler representation of the achievable rate region. At high signal-to-noise ratio (SNR), it is shown that the TG distribution is nearly optimal. It achieves the symmetric-capacity within a constant gap (independent of SNR), which approaches half a bit as the number of users grows. It also achieves the capacity region within a constant gap. At low SNR, it is shown that on-off keying (OOK) with time-division multipleaccess (TDMA) is optimal. This is interesting in practice since both OOK and TDMA have low complexity. At moderate SNR (typically [0,8] dB), a discrete distribution with a small alphabet size achieves fairly good performance.

On the Capacity of the Intensity-Modulation Direct-Detection Optical Broadcast Channel

KAUST Repository

Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

2016-01-01

The capacity of the intensity-modulation directdetection optical broadcast channel (OBC) is investigated, under both average and peak intensity constraints. An outer bound on the capacity region is derived by adapting Bergmans’ approach to the OBC. Inner bounds are derived by using superposition coding with either truncated-Gaussian (TG) distributions or discrete distributions. While the discrete distribution achieves higher rates, the TG distribution leads to a simpler representation of the achievable rate region. At high signal-to-noise ratio (SNR), it is shown that the TG distribution is nearly optimal. It achieves the symmetric-capacity within a constant gap (independent of SNR), which approaches half a bit as the number of users grows. It also achieves the capacity region within a constant gap. At low SNR, it is shown that on-off keying (OOK) with time-division multipleaccess (TDMA) is optimal. This is interesting in practice since both OOK and TDMA have low complexity. At moderate SNR (typically [0,8] dB), a discrete distribution with a small alphabet size achieves fairly good performance.

The Developmental Influence of Primary Memory Capacity on Working Memory and Academic Achievement

Science.gov (United States)

2015-01-01

In this study, we investigate the development of primary memory capacity among children. Children between the ages of 5 and 8 completed 3 novel tasks (split span, interleaved lists, and a modified free-recall task) that measured primary memory by estimating the number of items in the focus of attention that could be spontaneously recalled in serial order. These tasks were calibrated against traditional measures of simple and complex span. Clear age-related changes in these primary memory estimates were observed. There were marked individual differences in primary memory capacity, but each novel measure was predictive of simple span performance. Among older children, each measure shared variance with reading and mathematics performance, whereas for younger children, the interleaved lists task was the strongest single predictor of academic ability. We argue that these novel tasks have considerable potential for the measurement of primary memory capacity and provide new, complementary ways of measuring the transient memory processes that predict academic performance. The interleaved lists task also shared features with interference control tasks, and our findings suggest that young children have a particular difficulty in resisting distraction and that variance in the ability to resist distraction is also shared with measures of educational attainment. PMID:26075630

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-oxidation-adsorption process for emergent treatment of organic liquid spills.

Science.gov (United States)

Liu, Xianjun; Li, Yu; Zhang, Xingwang; Lei, Lecheng

2011-11-15

The feasibility and effectiveness of retention-oxidation-adsorption process (ROA) for the elimination of organic contaminants induced by chemical accidents were investigated in this study. Organobentonites (DTMA-, TTA-, CTMA- and OTMA-bentonite), potassium ferrate (Fe(VI)), ozone and granular activated carbon (GAC) were used as rapid and efficient materials in the treatment and recovery of organic liquid spills. Results indicated that the retention capacities of organobentonites (especially CTMA-bentonite) were much higher than that of natural bentonite towards the chosen organic compounds. Additionally, pH, oxidant dosage, initial concentration of contaminant and chemical structure had significant influences on the effectiveness of the oxidation process. In a pilot-scale experiment, the ferrate/GAC (F/G) and ozone/GAC (O/G) processes made a comparatively good performance in the treatment of wastewater containing aniline or nitrobenzene, with the removal efficiencies of the contaminants greater than 80%. Overall, the ROA process showed a high efficiency and steady operation in the removal of hazardous organic liquids and subsequent clean up of the contaminated site. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Biosorption and retention of several actinide and fission-product elements by biomass from Mycobacterium phlei

International Nuclear Information System (INIS)

Bouby, M.; MacCordick, H.J.; Billard, I.

1996-01-01

The properties of mobile, 5% w/w cell suspensions of Mycobacterium phlei have been examined for their capacity to adsorb and retain uranyl(VI) and neptunyl(V) cations from nitrate-buffered solutions at pH 1. Equilibrium conditions of sorption were attained after 3 hours for concentrations (C) in the range 0.015-18 mM cation and indicated a maximum specific adsorption capacity (Qe max ) of 182 μmol/g dry biomass for C ≥ 10 mM. NpO 2 + generally showed higher Qe values than UO 2 2+ at corresponding concentrations. Lixiviation tests with cation-loaded biomass in neutral and acidic media indicated that the extent of desorption did not vary extensively between pH 7 and pH 1 and did not exceed 3% for U and 1% for Np ions at pH 7 during 7-day periods of treatment. Analogous experiments with U-loaded biomass subjected to neutron activation prior to lixiviation enabled retention measurements for various fission-product isotopes produced in situ and showed that retention of 239 Np formed within the cellular matrix was >99% at pH 7 and ≥94% at pH 1. (author). 13 refs., 5 figs., 3 tabs

Visual Working Memory Capacity for Emotional Facial Expressions

Directory of Open Access Journals (Sweden)

Domagoj Švegar

2011-12-01

Full Text Available The capacity of visual working memory is limited to no more than four items. At the same time, it is limited not only by the number of objects, but also by the total amount of information that needs to be memorized, and the relation between the information load per object and the number of objects that can be stored into visual working memory is inverse. The objective of the present experiment was to compute visual working memory capacity for emotional facial expressions, and in order to do so, change detection tasks were applied. Pictures of human emotional facial expressions were presented to 24 participants in 1008 experimental trials, each of which began with a presentation of a fixation mark, which was followed by a short simultaneous presentation of six emotional facial expressions. After that, a blank screen was presented, and after such inter-stimulus interval, one facial expression was presented at one of previously occupied locations. Participants had to answer if the facial expression presented at test is different or identical as the expression presented at that same location before the retention interval. Memory capacity was estimated through accuracy of responding, by the formula constructed by Pashler (1988, adopted from signal detection theory. It was found that visual working memory capacity for emotional facial expressions equals 3.07, which is high compared to capacity for facial identities and other visual stimuli. The obtained results were explained within the framework of evolutionary psychology.

Spatial and Temporal Variability of Channel Retention in a Lowland Temperate Forest Stream Settled by European Beaver (Castor fiber

Directory of Open Access Journals (Sweden)

Mateusz Grygoruk

2014-09-01

Full Text Available Beaver ponds remain a challenge for forest management in those countries where expansion of beaver (Castor fiber is observed. Despite undoubted economic losses generated in forests by beaver, their influence on hydrology of forest streams especially in terms of increasing channel retention (amount of water stored in the river channel, is considered a positive aspect of their activity. In our study, we compared water storage capacities of a lowland forest stream settled by beaver in order to unravel the possible temporal variability of beaver’s influence on channel retention. We compared distribution, total damming height, volumes and areas of beaver ponds in the valley of Krzemianka (Northeast Poland in the years 2006 (when a high construction activity of beaver was observed and in 2013 (when the activity of beaver decreased significantly. The study revealed a significant decrease of channel retention of beaver ponds from over 15,000 m3 in 2006 to 7000 m3 in 2013. The total damming height of the cascade of beaver ponds decreased from 6.6 to 5.6 m. Abandoned beaver ponds that transferred into wetlands, where lost channel retention was replaced by soil and groundwater retention, were more constant over time and less vulnerable to the external disturbance means of water storage than channel retention. We concluded that abandoned beaver ponds played an active role in increasing channel retention of the river analyzed for approximately 5 years. We also concluded that if the construction activity of beaver was used as a tool (ecosystem service in increasing channel retention of the river valley, the permanent presence of beaver in the riparian zone of forest streams should have been assured.

Assessment of balance indicators for key fleet segments and review of national reports on Member States efforts to achieve balance between fleet capacity and fishing opportunities (STECF-13-28)

DEFF Research Database (Denmark)

Abella, Alvaro J.; Accadia, Paolo; Berkenhagen, Jörg

The Expert Working Group meeting of the Scientific, Technical and Economic Committee for Fisheries EWG-13-16 on Review of national reports on Member States efforts to achieve balance between fleet capacity and fishing opportunities was from September 29 – October 4, 2013 in Edinburgh. The report...

Crack-resistant polyimide coating for high-capacity battery anodes

Science.gov (United States)

Li, Yingshun; Wang, Shuo; Lee, Pui-Kit; He, Jieqing; Yu, Denis Y. W.

2017-10-01

Electrode cracking is a serious problem that hinders the application of many next-generation high-capacity anode materials for lithium-ion batteries. Even though nano-sizing the material can reduce fracturing of individual particles, capacity fading is still observed due to large volume change and loss of contact in the electrode during lithium insertion and extraction. In this study, we design a crack-resistant high-modulus polyimide coating with high compressive strength which can hold multiple particles together during charge and discharge to maintain contact. The effectiveness of the coating is demonstrated on tin dioxide, a high-capacity large-volume-change material that undergoes both alloy and conversion reactions. The polyimide coating improves capacity retention of SnO2 from 80% to 100% after 80 cycles at 250 mA g-1. Stable capacity of 585 mAh g-1 can be obtained even at 500 mA g-1 after 300 cycles. Scanning electron microscopy and in-situ dilatometry confirm that electrode cracking is suppressed and thickness change is reduced with the coating. In addition, the chemically-stable polyimide film can separate the surface from direct contact with electrolyte, improving coulombic efficiency to ∼100%. We expect the novel strategy of suppressing electrode degradation with a crack-resistant coating can also be used for other alloy and conversion-based anodes.

Retention in buprenorphine treatment is associated with improved HCV care outcomes.

Science.gov (United States)

Norton, B L; Beitin, A; Glenn, M; DeLuca, J; Litwin, A H; Cunningham, C O

2017-04-01

Persons who inject drugs, most of whom are opioid dependent, comprise the majority of the HCV infected in the United States. As the national opioid epidemic unfolds, increasing numbers of people are entering the medical system to access treatment for opioid use disorder, specifically with buprenorphine. Yet little is known about HCV care in patients accessing buprenorphine-based opioid treatment. We sought to determine the HCV prevalence, cascade of care, and the association between patient characteristics and completion of HCV cascade of care milestones for patients initiating buprenorphine treatment. We reviewed electronic health records of all patients who initiated buprenorphine treatment at a primary-care clinic in the Bronx, NY between January 2009 and January 2014. Of the 390 patients who initiated buprenorphine treatment, 123 were confirmed to have chronic HCV infection. The only patient characteristic associated with achieving HCV care milestones was retention in opioid treatment. Patients retained (vs. not retained) in buprenorphine treatment were more likely to be referred for HCV specialty care (63.1% vs. 34.0%, p<0.01), achieve an HCV-specific evaluation (40.8% vs. 21.3%, p<0.05), be offered HCV treatment (22.4% vs. 8.5%, p<0.05), and initiate HCV treatment (9.2% vs. 6.4%, p=0.6). Given the current opioid epidemic in the US and the growing number of people receiving buprenorphine treatment, there is an unprecedented opportunity to access and treat persons with HCV, reducing HCV transmission, morbidity and mortality. Retention in opioid treatment may improve linkage and retention in HCV care; innovative models of care that integrate opioid drug treatment with HCV treatment are essential. Copyright © 2017 Elsevier Inc. All rights reserved.

Influence of cement film thickness on the retention of implant-retained crowns.

Science.gov (United States)

Mehl, Christian; Harder, Sönke; Steiner, Martin; Vollrath, Oliver; Kern, Matthias

2013-12-01

The main goal of this study was to establish a new, high precision procedure to evaluate the influence of cement film thickness on the retention of cemented implant-retained crowns. Ninety-six tapered titanium abutments (6° taper, 4.3 mm diameter, Camlog) were shortened to 4 mm. Computer-aided design was used to design the crowns, and selective laser sintering, using a cobalt-chromium alloy, was used to produce the crowns. This method used a focused high-energy laser beam to fuse a localized region of metal powder to build up the crowns gradually. Before cementing, preset cement film thicknesses of 15, 50, 80, or 110 μm were established. Glass ionomer, polycarboxylate, or resin cements were used for cementation. After 3 days storage in demineralized water, the retention of the crowns was measured in tension using a universal testing machine. The cement film thicknesses could be achieved with a high level of precision. Interactions between the factors cement and cement film thickness could be found (p ≤ 0.001). For all cements, crown retention decreased significantly between a cement film thickness of 15 and 50 μm (p ≤ 0.001). At 15 μm cement film thickness, the resin cement was the most retentive cement, followed by the polycarboxylate and then the glass ionomer cement (p ≤ 0.05). The results suggest that cement film thickness has an influence on the retentive strength of cemented implant-retained crowns. © 2013 by the American College of Prosthodontists.

Effects of different N sources on riverine DIN export and retention in a subtropical high-standing island, Taiwan

Science.gov (United States)

Huang-Chuan, Jr.; Lee, Tsung-Yu; Lin, Teng-Chiu; Hein, Thomas; Lee, Li-Chin; Shih, Yu-Ting; Kao, Shuh-Ji; Shiah, Fuh-Kwo; Lin, Neng-Huei

2016-03-01

Increases in nitrogen (N) availability and mobility resulting from anthropogenic activities have substantially altered the N cycle, both locally and globally. Taiwan characterized by the subtropical montane landscape with abundant rainfall, downwind of the most rapidly industrializing eastern coast of China, can be a demonstration site for extremely high N input and riverine DIN (dissolved inorganic N) export. We used 49 watersheds with similar climatic and landscape settings but classified into low, moderate, and highly disturbed categories based on population density to illustrate their differences in nitrogen inputs (through atmospheric N deposition, synthetic fertilizers, and human emission) and DIN export ratios. Our results showed that the island-wide average riverine DIN export is ˜ 3800 kg N km-2 yr-1, approximately 18 times the global average. The average riverine DIN export ratios are 0.30-0.51, which are much higher than the averages of 0.20-0.25 of large rivers around the world, indicating excessive N input relative to ecosystem demand or retention capacity. The low disturbed watersheds have a high N retention capacity and DIN export ratios of 0.06-0.18 in spite of the high N input (˜ 4900 kg N km-2 yr-1). The high retention capacity is likely due to effective uptake by secondary forests in the watersheds. The moderately disturbed watersheds show a linear increase in DIN export with increases in total N inputs and mean DIN export ratios of 0.20 to 0.31. The main difference in land use between low and moderately disturbed watersheds is the greater proportion of agricultural land cover in the moderately disturbed watersheds. Thus, their greater DIN export could be attributed to N fertilizers used in the agricultural lands. The greater export ratios also imply that agricultural lands have a lower proportional N retention capacity and that reforestation could be an effective land management practice to reduce riverine DIN export. The export ratios of the

Non-coherent capacity of secret-key agreement with public discussion

KAUST Repository

Agrawal, Anurag

2011-06-01

We study the Rayleigh fading non-coherent capacity of secret-key agreement with public discussion, where neither the sender nor the receivers have access to instantaneous channel state information (CSI) of any channel. We present two results. At high Signal-to-Noise Ratio (SNR), the secret-key capacity is bounded in SNR, regardless of the number of antennas at each terminal. Second, for a system with a single antenna at both the legitimate and the eavesdropper terminals and an arbitrary number of transmit antennas, the secret-key capacity-achieving input distribution is discrete, with a finite number of mass points. Numerically we observe that at low-SNR, the capacity achieving distribution has two mass points with one of them at the origin. © 2011 IEEE.

Non-coherent capacity of secret-key agreement with public discussion

KAUST Repository

Agrawal, Anurag; Rezki, Zouheir; Khisti, Ashish J.; Alouini, Mohamed-Slim

2011-01-01

We study the Rayleigh fading non-coherent capacity of secret-key agreement with public discussion, where neither the sender nor the receivers have access to instantaneous channel state information (CSI) of any channel. We present two results. At high Signal-to-Noise Ratio (SNR), the secret-key capacity is bounded in SNR, regardless of the number of antennas at each terminal. Second, for a system with a single antenna at both the legitimate and the eavesdropper terminals and an arbitrary number of transmit antennas, the secret-key capacity-achieving input distribution is discrete, with a finite number of mass points. Numerically we observe that at low-SNR, the capacity achieving distribution has two mass points with one of them at the origin. © 2011 IEEE.

The effect of student-centered and teacher-centered instruction with and without conceptual advocacy on biology students' misconceptions, achievement, attitudes toward science, and cognitive retention

Science.gov (United States)

Gallop, Roger Graham

The purpose of this study was to investigate the effect of student-centered and teacher-centered instructional strategies with and without conceptual advocacy (CA) on ninth-grade biology students' misconceptions (MIS), biology achievement (ACH), attitudes toward science (ATT), and cognitive retention of scientific method and measurement, spontaneous generation, and characteristics of living things. Students were purposively selected using intact classes and assigned to one of four treatment groups (i.e., student-centered instruction without CA, student-centered instruction with CA, teacher-centered instruction with CA, and teacher-centered instruction without CA). A modified quasi-experimental design was used in which students were not matched in the conventional sense but instead, groups were shown to be equivalent on the dependent measure via a pretest. A 5-day treatment implementation period addressed science conceptions under investigation. The treatment period was based on the number of class periods teachers at the target school actually spend teaching the biological concepts under investigation using traditional instruction. At the end of the treatment period, students were posttested using the Concepts in Biology instrument and Science Questionnaire. Eight weeks after the posttest, these instruments were administered again as a delayed posttest to determine cognitive retention of the correct biological conceptions and attitudes toward science. MANCOVA and follow-up univariate ANCOVA results indicated that student-centered instruction without CA (i.e., Group 1) did not have a significant effect on students' MIS, ACH, and ATT (F = .029, p = .8658; F = .002, p =.9688, F = .292, p = .5897, respectively). On the other hand, student-centered instruction with CA (i.e., Group 2) had a significant effect on students' MIS and ACH (F =10.33, p = .0016 and F = 10.17, p = .0017, respectively), but did not on ATT (F = .433, p = .5117). Teacher-centered instruction with

Research projects and capacity building | Breen | Water SA

African Journals Online (AJOL)

... by capacity building in the context of research projects. Based on this interpretation, reasonable and unreasonable expectations with respect to the extent to which capacity building can be achieved within a given project duration are discussed. A model is suggested, which would improve understanding and delivery and ...

Methodology Research on Evaluating the Developmental and Retentive Capacity Level of Human Single -joint Muscular Power in Mode of Isotonic Test%应用等张模式测定人体单关节肌群功率发展与保持能力的方法学研究

Institute of Scientific and Technical Information of China (English)

徐红旗; 张欣; 冉令华; 杨帆; 史冀鹏; 王安利; 郑秀瑗

2011-01-01

人体肌肉功率的发展与保持能力在完成生产劳动、日常体力活动和体育运动中具有重要的作用.本文以12名健康普通大学生为研究对象,运用模拟仿真测试评价训练系统( BTE PrimusRS)的等张测量模式来探讨人体单关节肌群功率发展与保持能力的测评方法.结果表明BTE PrimusRS系统能客观、准确地评价人体单关节肌群功率发展与保持能力的水平；此等张测试模式下,50％等长峰值肌力(或力矩)的阻力负荷设置较为合理；等长峰值肌力应采用非爆发式静力性测量模式获得.%The developmental and retentive capacity of muscular power is of great importance to human endeavor in productive labor, physical activities of daily living and sports events. Twelve healthy college students volunteered to participate in this study; the purpose was to explore the measurement method about the developmental and retentive capacity of human single -joint muscular power, combined with the mode of isotonic test on BTE PrimusRS system. The results show that BTE PrimusRS system could objectively and accurately evaluate the developmental and retentive capacity level of human single -joint muscular power. The reasonable load resistance was 50% of the isometric peak strength or torque (IPS or IPT) in the isotonic test; the mode of isometric peak strength (IPS) should be non -explosively static.

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...

Effect of ceramic membrane channel diameter on limiting retentate protein concentration during skim milk microfiltration.

Science.gov (United States)

Adams, Michael C; Barbano, David M

2016-01-01

Our objective was to determine the effect of retentate flow channel diameter (4 or 6mm) of nongraded permeability 100-nm pore size ceramic membranes operated in nonuniform transmembrane pressure mode on the limiting retentate protein concentration (LRPC) while microfiltering (MF) skim milk at a temperature of 50°C, a flux of 55 kg · m(-2) · h(-1), and an average cross-flow velocity of 7 m · s(-1). At the above conditions, the retentate true protein concentration was incrementally increased from 7 to 11.5%. When temperature, flux, and average cross-flow velocity were controlled, ceramic membrane retentate flow channel diameter did not affect the LRPC. This indicates that LRPC is not a function of the Reynolds number. Computational fluid dynamics data, which indicated that both membranes had similar radial velocity profiles within their retentate flow channels, supported this finding. Membranes with 6-mm flow channels can be operated at a lower pressure decrease from membrane inlet to membrane outlet (ΔP) or at a higher cross-flow velocity, depending on which is controlled, than membranes with 4-mm flow channels. This implies that 6-mm membranes could achieve a higher LRPC than 4-mm membranes at the same ΔP due to an increase in cross-flow velocity. In theory, the higher LRPC of the 6-mm membranes could facilitate 95% serum protein removal in 2 MF stages with diafiltration between stages if no serum protein were rejected by the membrane. At the same flux, retentate protein concentration, and average cross-flow velocity, 4-mm membranes require 21% more energy to remove a given amount of permeate than 6-mm membranes, despite the lower surface area of the 6-mm membranes. Equations to predict skim milk MF retentate viscosity as a function of protein concentration and temperature are provided. Retentate viscosity, retentate recirculation pump frequency required to maintain a given cross-flow velocity at a given retentate viscosity, and retentate protein

THE PRESENT CONDITION OF SMALL WATER RETENTION AND THE PROSPECTS OF ITS DEVELOPMENT USING THE EXAMPLE OF THE PODLASKIE VOIVODESHIP

Directory of Open Access Journals (Sweden)

Joanna Szczykowska

2014-07-01

Full Text Available The necessity and purposefulness of the investments related to water retention are justified mostly due to the preservation of the environment equilibrium as well as due to its farming, anti-flood, landscape and recreation aspects. Reasonable water management where various forms of retention are used gives large chances for the mitigation of the effects of unfavorable phenomena related to its insufficient amount. The creation of plans regarding the formation of reservoirs accumulating water is not necessarily synonymous with their realization. The reason of problems connected with the implementation of plans regarding the formation of new reservoirs lies mainly in financial measures and in problems with obtaining them. Water deficit in Poland is the reason for which the principles of its national usage need to be complied with. Realization of plans at both Voivodeship and municipality level that are focused on small retention will contribute to considerable increase in the retention capacity and will enable considerable increase in available resources in hydrographic catchments of both the characterized area and the entire country. The paper presents the characteristics of the present state and assumes the perspective development of small water retention in the Podlaskie Voivodeship using the example of the Podlaskie Voivodeship.

Achieving Health SDG 3 in Africa through NGO Capacity Building - Insights from the Gates Foundation Investment in Partnership in Advocacy for Child and Family Health (PACFaH) Project.

Science.gov (United States)

Walker, Judith-Ann

2016-09-01

As global impact investors gear up to support roll out of the Sustainable Development Goals in the developing world, African CSOs are urged to ensure that governments shift health funding sources away from aid and loans to innovative domestic funding sources which prioritize health. To do so, African CSOs require support to build their capacity for policy and budget advocacy. Governments and development partners have failed to invest in long term capacity building projects for indigenous NGOs and instead support INGOs to push the health advocacy agenda forward. In Nigeria, the Gates foundation has risen to the challenge of building capacity of indigenous NGOs for social accountability in child and family health. The 3 year pilot project - Partnership for Advocacy in Child and Family Health Project (PACFaH) mainstreams capacity building as an effective implementation strategy for 8 indigenous NGOs to deliver on - policy; budgetary; legislative; and administrative advocacy in four issue areas: 1) family planning; 2) nutrition; 3) routine immunization; and 4) reduction of under-5 deaths from diarrhea and pneumonia. This paper documents the achievements of the eight advocacy NGOs in PACFaH, at midterm and notes that while there have been challenges, working through capacity building as an implementation strategy has enabled the local groups in the delivery of evidence based advocacy.

Influence of aging on the retention of elemental radioiodine by deep bed carbon filters under accident conditions

International Nuclear Information System (INIS)

Deuber, H.

1985-01-01

No significant difference was found in the retention of I-131 loaded as I 2 , by various impregnated activated carbons that had been aged in the containment exhaust air of a pressurized water reactor over a period of 12 months. In all the cases, the I-131 passing through deep beds of carbon was in a nonelemental form. It was concluded that a minimum retention of 99.99%, as required by new guidelines for certain accident filters, can be equally well achieved with various carbons in deep beds

Optimization of wetland restoration siting and zoning in flood retention areas of river basins in China: A case study in Mengwa, Huaihe River Basin

Science.gov (United States)

Zhang, Xiaolei; Song, Yuqin

2014-11-01

Wetland restoration in floodplains is an ecological solution that can address basin-wide flooding issues and minimize flooding and damages to riverine and downstream areas. High population densities, large economic outputs, and heavy reliance on water resources make flood retention and management pressing issues in China. To balance flood control and sustainable development economically, socially, and politically, flood retention areas have been established to increase watershed flood storage capacities and enhance the public welfare for the populace living in the areas. However, conflicts between flood storage functions and human habitation appear irreconcilable. We developed a site-specific methodology for identifying potential sites and functional zones for wetland restoration in a flood retention area in middle and eastern China, optimizing the spatial distribution and functional zones to maximize flood control and human and regional development. This methodology was applied to Mengwa, one of 21 flood retention areas in China's Huaihe River Basin, using nine scenarios that reflected different flood, climatic, and hydraulic conditions. The results demonstrated improved flood retention and ecological functions, as well as increased economic benefits.

Capacity of Intelligent Underlay and Overlay Network

DEFF Research Database (Denmark)

Ling, Yim; Elling, Jan; Nielsen, Thomas Toftegaard

1996-01-01

traffic. The formulas of the model have been implemented with the use of MatLab. To verify the model, measurement methods have been developed to collect the teletraffic information in a real-live GSM network. The measured data indicates that the teletraffic model describes the capacity with high accuracy...... and therefore can be used to dimension the network. The model shows that the increase of capacity for a GSM network with 34 frequencies is about 30%. Further capacity enhancement can be achieved by intelligent frequency planning method which is currently being developed...

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.

Achieving the projected capacity of the Stanyantsi mine

Energy Technology Data Exchange (ETDEWEB)

Dragiev, D

1979-07-01

Equipment includes 2 Skoda excavators, one Skoda E-25 power shovel, KraZ dump trucks, graders and S-100 bulldozers. The annual production of 700,000 tons is consumed by the Maritsa-Iztok 2 power plant. To increase production and eventually achieve the originally projected output of 1,400,000 tons annually it is necessary to procure an ESh-10/70 power shovel for surface work, employ all available excavating equipment in surface mining and complete an estimate of all needed mining equipment. The new exploitation plan calls for a reorganization of surface levels, realignment of surface drainage, arrangements for employment of two conveyor belts, construction of a service base for the ESh-10/70 power shovel, training of operators and maintenance crews for the ESh-10/70 power shovel, installation of new electric lines and substations and resurfacing access roads with gravel.

Preparation and properties of a double-coated slow-release NPK compound fertilizer with superabsorbent and water-retention.

Science.gov (United States)

Wu, Lan; Liu, Mingzhu; Rui Liang

2008-02-01

A double-coated slow-release NPK compound fertilizer with superabsorbent and water-retention was prepared by crosslinked poly(acrylic acid)/diatomite - containing urea (the outer coating), chitosan (the inner coating), and water-soluble granular fertilizer NPK (the core). The effects of the amount of crosslinker, initiator, degree of neutralization of acrylic acid, initial monomer and diatomite concentration on water absorbency were investigated and optimized. The water absorbency of the product was 75 times its own weight if it was allowed to swell in tap water at room temperature for 2 h. Atomic absorption spectrophotometer and element analysis results showed that the product contained 8.47% potassium (shown by K(2)O), 8.51% phosphorus (shown by P(2)O(5)), and 15.77% nitrogen. We also investigated the water-retention property of the product and the slow release behavior of N, P and K in the product. This product with excellent slow release and water-retention capacity, being nontoxic in soil and environment-friendly, could be especially useful in agricultural and horticultural applications.

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)

An assessment of the effect on Olkiluoto repository capacity achievable with advanced fuel cycles

Energy Technology Data Exchange (ETDEWEB)

Juutilainen, P.; Viitanen, T. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland)

2013-07-01

Previously a few scenarios have been simulated for transition from thermal to fast reactor fleet in Finland in order to determine how much the transuranic inventory could be reduced with the partitioning and transmutation (P-T) technologies. Those calculations, performed with COSI6 code developed by CEA, are extended in the present study, in which the effect of P-T on the capacity of the planned final disposal repository at Olkiluoto (Finland) is evaluated by taking into account the created fission products and transuranic residuals from the reprocessing operations. The decay heat is assumed to be the most restrictive factor in defining the waste disposal packing density. The repository capacity evaluation of this study is based on the comparison of the decay heats produced by the deposited waste in various scenarios. The reference scenario of this article involves only Light Water Reactors (LWR) in an open fuel cycle. The capacity requirement of the geological repository is estimated in a few closed fuel cycle scenarios, all including actinide transmutation with Fast Reactors (FR). The comparison between the P-T scenarios and reference is based on the decay heat production of the deposited waste. The COSI6 code is used for simulations to provide the repository decay heat curves. Applying the closed fuel cycle would change the disposal concept and schedule, because of which it is not quite straightforward to assess the impact of P-T on the capacity. However, it can be concluded that recycling the transuranic nuclides probably decreases the required volume for the disposal, but thermal dimensioning analysis is needed for more specific conclusions.

Pedotransfer functions to estimate soil water content at field capacity and permanent wilting point in hot arid western India

NARCIS (Netherlands)

Santra, P.; Kumar, M.; Kumawat, R.N.; Painuli, D.K.; Hati, K.M.; Heuvelink, G.B.M.; Batjes, N.H.

2018-01-01

Characterization of soil water retention, e.g., water content at field capacity (FC) and permanent wilting point (PWP) over a landscape plays a key role in efficient utilization of available scarce water resources in dry land agriculture; however, direct measurement thereof for multiple locations in

Multiseed liposomal drug delivery system using micelle gradient as driving force to improve amphiphilic drug retention and its anti-tumor efficacy.

Science.gov (United States)

Zhang, Wenli; Li, Caibin; Jin, Ya; Liu, Xinyue; Wang, Zhiyu; Shaw, John P; Baguley, Bruce C; Wu, Zimei; Liu, Jianping

2018-11-01

To improve drug retention in carriers for amphiphilic asulacrine (ASL), a novel active loading method using micelle gradient was developed to fabricate the ASL-loaded multiseed liposomes (ASL-ML). The empty ML were prepared by hydrating a thin film with empty micelles. Then the micelles in liposomal compartment acting as 'micelle pool' drove the drug to be loaded after the outer micelles were removed. Some reasoning studies including critical micelle concentration (CMC) determination, influencing factors tests on entrapment efficiency (EE), structure visualization, and drug release were carried out to explore the mechanism of active loading, ASL location, and the structure of ASL-ML. Comparisons were made between pre-loading and active loading method. Finally, the extended drug retention capacity of ML was evaluated through pharmacokinetic, drug tissue irritancy, and in vivo anti-tumor activity studies. Comprehensive results from fluorescent and transmission electron microscope (TEM) observation, encapsulation efficiency (EE) comparison, and release studies demonstrated the formation of ML-shell structure for ASL-ML without inter-carrier fusion. The location of drug mainly in inner micelles as well as the superiority of post-loading to the pre-loading method , in which drug in micelles shifted onto the bilayer membrane was an additional positive of this delivery system. It was observed that the drug amphiphilicity and interaction of micelles with drug were the two prerequisites for this active loading method. The extended retention capacity of ML has been verified through the prolonged half-life, reduced paw-lick responses in rats, and enhanced tumor inhibition in model mice. In conclusion, ASL-ML prepared by active loading method can effectively load drug into micelles with expected structure and improve drug retention.

The Effect of Case Teaching on Meaningful and Retentive Learning When Studying Genetic Engineering

Science.gov (United States)

Güccük, Ahmet; Köksal, Mustafa Serdar

2017-01-01

The purpose of this study is to investigate the effects of case teaching on how students learn about genetic engineering, in terms of meaningful learning and retention of learning. The study was designed as quasi-experimental research including 63 8th graders (28 boys and 35 girls). To collect data, genetic engineering achievement tests were…

Optimization of strawberry disinfection by fogging of a mixture of peracetic acid and hydrogen peroxide based on microbial reduction, color and phytochemicals retention.

Science.gov (United States)

Van de Velde, Franco; Vaccari, María Celia; Piagentini, Andrea Marcela; Pirovani, María Élida

2016-09-01

The fogging of strawberries using a environmentally friendly sanitizer mixture of peracetic acid (5%) and hydrogen peroxide (20%) was performed in a model chamber and modeled as a function of the concentration (3.4, 20.0, 60.0, 100.0 and 116.6 µL sanitizer L(-) (1) air chamber) and the treatment time (5.7, 15.0, 37.5, 60.0 and 69.3 min). The sanitizer fogging was adequate for reducing total mesophilic microbial and yeasts and moulds counts of fruits until seven days of storage at 2℃. However, sanitizer oxidant properties adversely affected the content of total anthocyanins, total phenolics, vitamin C, and antioxidant capacity to various degrees, with some deleterious changes in the fruits color, depending on the fogging conditions. A multiple numeric response optimization was developed based on 2.0 log microbiological reduction, maximum phytochemicals and antioxidant capacity retentions, with no changes in the fruits color, being the optimal fogging conditions achieved: 10.1 µL sanitizer L(-1) air chamber and 29.6 min. The fogging of strawberries at these conditions may represent a promising postharvest treatment option for extending their shelf-life without affecting their sensory quality and bioactive properties. © The Author(s) 2016.

Temporal precision and the capacity of auditory-verbal short-term memory.

Science.gov (United States)

Gilbert, Rebecca A; Hitch, Graham J; Hartley, Tom

2017-12-01

The capacity of serially ordered auditory-verbal short-term memory (AVSTM) is sensitive to the timing of the material to be stored, and both temporal processing and AVSTM capacity are implicated in the development of language. We developed a novel "rehearsal-probe" task to investigate the relationship between temporal precision and the capacity to remember serial order. Participants listened to a sub-span sequence of spoken digits and silently rehearsed the items and their timing during an unfilled retention interval. After an unpredictable delay, a tone prompted report of the item being rehearsed at that moment. An initial experiment showed cyclic distributions of item responses over time, with peaks preserving serial order and broad, overlapping tails. The spread of the response distributions increased with additional memory load and correlated negatively with participants' auditory digit spans. A second study replicated the negative correlation and demonstrated its specificity to AVSTM by controlling for differences in visuo-spatial STM and nonverbal IQ. The results are consistent with the idea that a common resource underpins both the temporal precision and capacity of AVSTM. The rehearsal-probe task may provide a valuable tool for investigating links between temporal processing and AVSTM capacity in the context of speech and language abilities.

Incorporated Woodchips as a Novel Intervention to Support Plant Growth through Increased Water Holding Capacity and Nutrient Retention in Sandy Degraded Soils

Science.gov (United States)

Menzies, E.; Schneider, R.; Walter, T.

2017-12-01

According to the World Wildlife Federation's most recent Plow Print report 53 million acres of temperate, water limited, grasslands across the Great Plains have been converted to agriculture since 2009. This conversion very often begins the process of soil degradation which can lead to desertification and the necessity to convert more land to agriculture. The most common solution to this problem is improved crop efficiency to reduce conversion of grasslands to agriculture while still producing enough food for us all. We suggest that while that may be the beginning of the solution, degraded soils need to be rehabilitated and brought back into production to adequately provide food crops for the increasing population of the globe. Incorporated woodchips can be used to improve the soils' water holding capacity and nutrient (N and P) retention. In a previous study we observed an increase in the gravimetric water content and a decrease in soluble N and P losses when fertilizers were applied in liquid form in soil columns with incorporated woodchips (see attached figure). In this study we examine the availability of the retained water and nutrients to grasses to determine the extent to which this intervention might be used to reestablish plant growth in degraded sandy soils. We also begin examining the quantity of woodchips necessary to retain sufficient water and nutrients to sustain the growth of grasses over the course of a growing season. A laboratory soil column study is currently underway to examine these questions; the results of this study will be presented at the Fall Meeting.

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

OpenAIRE

Ertep, Rifat Hakan

1996-01-01

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

Multi-lane Roundabout Capacity Evaluation

Directory of Open Access Journals (Sweden)

Ammar Šarić

2017-07-01

Full Text Available Although two-lane roundabouts theoretically exhibit excellent operating performance, in practice, safety problems arise because of inappropriate driving behavior. Turbo roundabouts, which are characterized by a much higher level of safety, are alternatives to classic two-lane roundabouts, but the capacity-related benefits derived from such roundabouts remain an open issue. Accordingly, this study uses an equilibrium traffic flow allocation approach to evaluate multi-lane roundabout capacity based on gap acceptance theory. Capacity levels are calculated and compared for different gap acceptance parameters, including local parameters, and different traffic flow scenarios. It is found that the capacity of minor approaches on turbo roundabouts is always higher than on two-lane roundabouts, but that the main approaches on two-lane roundabouts exhibit better performance in terms of fully equilibrium traffic allocation. This state, however, cannot be achieved for every demand scenario. The results depend strongly on traffic movements and gap acceptance parameters indicating the need for local calibration processes.

Gastric emptying of water in children with severe functional fecal retention

Directory of Open Access Journals (Sweden)

V.P.I. Fernandes

Full Text Available The objective of this study was to evaluate gastric emptying (GE in pediatric patients with functional constipation. GE delay has been reported in adults with functional constipation. Gastric emptying studies were performed in 22 children with chronic constipation, fecal retention and fecal incontinence, while presenting fecal retention and after resuming regular bowel movements. Patients (18 boys, median age: 10 years; range: 7.2 to 12.7 years were evaluated in a tertiary pediatric gastroenterology clinic. Gastric half-emptying time of water (reference range: 12 ± 3 min was measured using a radionuclide technique immediately after first patient evaluation, when they presented fecal impaction (GE1, and when they achieved regular bowel movements (GE2, 12 ± 5 weeks after GE1. At study admission, 21 patients had reported dyspeptic symptoms, which were completely relieved after resuming regular bowel movements. Medians (and interquartile ranges for GE1 and GE2 were not significantly different [27.0 (16 and 27.5 (21 min, respectively (P = 0.10]. Delayed GE seems to be a common feature among children with chronic constipation and fecal retention. Resuming satisfactory bowel function and improvement in dyspeptic symptoms did not result in normalization of GE data.

Capacity Decay Mitigation by Asymmetric Positive/Negative Electrolyte Volumes in Vanadium Redox Flow Batteries.

Science.gov (United States)

Park, Jong Ho; Park, Jung Jin; Park, O Ok; Yang, Jung Hoon

2016-11-23

Capacity decay in vanadium redox flow batteries during charge-discharge cycling has become an important issue because it lowers the practical energy density of the battery. The battery capacity tends to drop rapidly within the first tens of cycles and then drops more gradually over subsequent cycles during long-term operation. This paper analyzes and discusses the reasons for this early capacity decay. The imbalanced crossover rate of vanadium species was found to remain high until the total difference in vanadium concentration between the positive and negative electrolytes reached almost 1 mol dm -3 . To minimize the initial crossover imbalance, we introduced an asymmetric volume ratio between the positive and negative electrolytes during cell operation. Changing this ratio significantly reduced the capacity fading rate of the battery during the early cycles and improved its capacity retention at steady state. As an example, the practical energy density of the battery increased from 15.5 to 25.2 Wh L -1 simply after reduction of the positive volume by 25 %. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Utilizing joint routing and capacity assignment algorithms to achieve inter- and intra-group delay fairness in multi-rate multicast wireless sensor networks.

Science.gov (United States)

Lin, Frank Yeong-Sung; Hsiao, Chiu-Han; Lin, Leo Shih-Chang; Wen, Yean-Fu

2013-03-14

Recent advance in wireless sensor network (WSN) applications such as the Internet of Things (IoT) have attracted a lot of attention. Sensor nodes have to monitor and cooperatively pass their data, such as temperature, sound, pressure, etc. through the network under constrained physical or environmental conditions. The Quality of Service (QoS) is very sensitive to network delays. When resources are constrained and when the number of receivers increases rapidly, how the sensor network can provide good QoS (measured as end-to-end delay) becomes a very critical problem. In this paper; a solution to the wireless sensor network multicasting problem is proposed in which a mathematical model that provides services to accommodate delay fairness for each subscriber is constructed. Granting equal consideration to both network link capacity assignment and routing strategies for each multicast group guarantees the intra-group and inter-group delay fairness of end-to-end delay. Minimizing delay and achieving fairness is ultimately achieved through the Lagrangean Relaxation method and Subgradient Optimization Technique. Test results indicate that the new system runs with greater effectiveness and efficiency.

Impacts of Return-to-Work Type and Period on Job Retention in Workers with Occupational Injuries and Diseases.

Science.gov (United States)

Jeong, Inchul; Park, Jae Bum; Kim, Hyoung Ryoul; Yoon, Jin Ha; Won, Jong Uk; Roh, Jaehoon

2018-01-01

Despite the necessity of job retention in achieving return-to-work (RTW) goals, many workers leave their jobs after returning to work. The objective of this study was to examine the impacts of RTW type and period on job retention in Korean workers with occupational injuries and diseases. Data were derived from the Panel Study of Worker's Compensation Insurance, including data from 2,000 systemically sampled workers who had finished recuperation in 2012; three waves of survey data were included in the analyses. Workers who returned to work (n = 1,610) were included in the analysis of the relationship between RTW type and job retention, and 664 workers who returned to their original workplaces were included in the analysis of the relationship between RTW period and job retention. The participants completed a questionnaire, and administrative data were provided by workers' compensation insurance. A Cox proportional-hazards regression analysis showed an increased hazard ratio (HR) for non-retention of 2.66 (95% confidence interval, 2.11-3.35) in reemployed workers compared to that in workers returning to their original workplaces. Among workers returning to their original workplaces, HRs for non-retention were increased in workers with a RTW period of 13-24 months (3.03 [1.52-6.04]) and > 24 months (5.33 [2.14-13.25]) compared to workers with a RTW period of ≤ 3 months. RTW type and period were significantly related to job retention, suggesting that policies for promoting job retention rate should be implemented. © 2018 The Korean Academy of Medical Sciences.

The oil industry experience. Technology cooperation and capacity building

International Nuclear Information System (INIS)

1995-01-01

Technology cooperation is defined as a process of constructive interaction with local, national and international partners to select and apply appropriate technology systems to achieve environmentally sound forms of economic development. Capacity building is the process of constructive interaction between countries and the private sector designed to develop the capability and skills to achieve environmentally sound forms of economic development through the use of modern technologies and management systems, a competent workforce and appropriate laws and regulations. Twelve case histories are presented which demonstrate the efforts of the oil industry to work in partnership with governments, contractors, suppliers and communities in technology cooperation and capacity building to achieve the goals of Agenda 21 which emerged as an action plan from the Rio Earth Summit in 1992. (UK)

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

The Effect of Internal Marketing on Employee retention in Pakistani Banks

OpenAIRE

Naveed Ahmad; Nadeem Iqbal; Muhammad Sheeraz

2012-01-01

This research investigates the effects of internal marketing on employee retention in banking sector of district D. G. Khan, Pakistan. Marketing is the process by which the external customers are satisfied through exact identification of their needs and wants. When we do the same thing- satisfaction- with our employees then this is named as internal marketing. This approach is used to motivate, align and integrate the employees towards the achievement of organizational goals. The motto of int...

The effect of secondary school study skills preparation on first-year university achievement

NARCIS (Netherlands)

Jansen, Ellen P. W. A.; Suhre, Cor J. M.

2010-01-01

Although many studies have revealed the importance of study skills for students' first-year performance and college retention, the extent of the impact of study skills preparation on students' academic achievement is less clear. This paper explores the impact of pre-university study skills

Study of the retention of organic pollutants starting from aqueous solutions by adsorption on local clays

International Nuclear Information System (INIS)

Dali-Youcef, Z; Queneudec, M; Dheilly, R M

2010-01-01

A new adsorbent, mud activated with ammonium chloride, was characterized and employed for the removal of organic pollutants such as phenol and red dye used in the industry of textile, from aqueous solutions. The elaborated material is then used in the treatment of a textile industry waste-water. The use of ammonium chloride activates the mud by increasing its specific surface and thus increases its moisture-holding capacity of phenol and red dye. The experimental data for removal of phenol were analyzed by the Freundlich isotherm and the Langmuir isotherm. Equilibrium data fitted well with the Langmuir model and Freundlich model with maximum adsorption capacity of 40.81 mg/g. The use of column with high diameter facilitates the retention of the red dye.

Three-dimensional graphene sheets with NiO nanobelt outgrowths for enhanced capacity and long term high rate cycling Li-ion battery anode material

Science.gov (United States)

Shi, Waipeng; Zhang, Yingmeng; Key, Julian; Shen, Pei Kang

2018-03-01

An efficient synthesis method to grow well attached NiO nanobelts from 3D graphene sheets (3DGS) is reported herein. Ni-ion exchanged resin provides the initial Ni reactant portion, which serves both as a catalyst to form 3DGS and then as a seeding agent to grow the NiO nanobelts. The macroporous structure of 3DGS provides NiO containment to achieve a high cycling stability of up to 445 mAh g-1 after 360 cycles (and >112% capacity retention after 515 cycles) at a high current density of 2 A g-1. With a 26.8 wt.% content of NiO on 3DGS, increases in specific and volumetric capacity were 41.6 and 75.7% respectively over that of 3DGS at matching current densities. Therefore, the seeded growth of NiO nanobelts from 3DGS significantly boosts volumetric capacity, while 3DGS enables high rate long term cycling of the NiO. The high rate cycling stability of NiO on 3DGS can be attributed to (i) good attachment and contact to the large surface of 3DGS, (ii) high electron conductivity and rapid Li-ion transfer (via the interconnected, highly conductive graphitized walls of 3DGS) and (iii) buffering void space in 3DGS to contain volume expansion of NiO during charge/discharge.

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

Spatial Variation of Phosphorous Retention Capacity in Subsurface Flow Constructed Wetlands: Effect of Wetland Type and Inflow Loading.

Directory of Open Access Journals (Sweden)

Guangwei Yu

Full Text Available For verification of spatial distribution of phosphorous retention capacity in constructed wetlands systems(CWs, two horizontal subsurface flow(HSSF CWs and two vertical subsurface flow(VSSF CWs, using sand as substrate and Typha latifolia as wetland plants, were constructed and put into use for synthetic wastewater treatment. Five months later, significant spatial variations of TP and inorganic phosphorus(Ca-P, Fe-P and Al-P were observed, which were found to be greatly affected by CWs type and hydraulic loading. The results revealed that though spatial distribution of Fe-P and Al-P displayed a similar order of substrate content as "rhizosphere" > "near-rhizosphere" > "non-rhizosphere" and "inflow section" > "outflow section" regardless of types and loading, the distribution of Ca-P was positively correlated to that of Fe-P and Al-P in HSSF CWs, while negative correlation was shown in VSSF CWs. As a result, TP spatial distribution in HSSF CWs demonstrated a greater dissimilarity than that in VSSF CWs. For HSSF CWs with low hydraulic loading, the lowest TP content was found in non-rhizosphere substrate of outflow section, while the highest one was discovered in rhizonsphere substrate of inflow section. The values in 6 parts of areas ranged from 0.138 g·kg-1 to 2.710 g·kg-1, which also were from -33.5% to 1209% compared to the control value. On contrast, spatial difference of TP content in substrates of VSSF CWs was insignificant, with a variation ranging from 0.776 g·kg-1 to 1.080 g·kg-1, that was 275% to 421% higher than the control value. In addition, when hydraulic loading was increased, TP content in VSSF CWs sharply decreased, ranging from 0.210 g·kg-1 to 0.634 g·kg-1. Meanwhile, dissimilarity of TP spatial distribution in HSSF CWs was reduced, with TP content ranging from 0.258 g·kg-1 to 2.237 g·kg-1. The results suggested that P spatial distribution should be taken into account for CWs design and operation.

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...

Hydrogen retention in ion irradiated steels

International Nuclear Information System (INIS)

Hunn, J.D.; Lewis, M.B.; Lee, E.H.

1998-01-01

In the future 1--5 MW Spallation Neutron Source, target radiation damage will be accompanied by high levels of hydrogen and helium transmutation products. The authors have recently carried out investigations using simultaneous Fe/He,H multiple-ion implantations into 316 LN stainless steel between 50 and 350 C to simulate the type of radiation damage expected in spallation neutron sources. Hydrogen and helium were injected at appropriate energy and rate, while displacement damage was introduced by nuclear stopping of 3.5 MeV Fe + , 1 microm below the surface. Nanoindentation measurements showed a cumulative increase in hardness as a result of hydrogen and helium injection over and above the hardness increase due to the displacement damage alone. TEM investigation indicated the presence of small bubbles of the injected gases in the irradiated area. In the current experiment, the retention of hydrogen in irradiated steel was studied in order to better understand its contribution to the observed hardening. To achieve this, the deuterium isotope ( 2 H) was injected in place of natural hydrogen ( 1 H) during the implantation. Trapped deuterium was then profiled, at room temperature, using the high cross-section nuclear resonance reaction with 3 He. Results showed a surprisingly high concentration of deuterium to be retained in the irradiated steel at low temperature, especially in the presence of helium. There is indication that hydrogen retention at spallation neutron source relevant target temperatures may reach as high as 10%

Benefits from retrieval practice are greater for students with lower working memory capacity.

Science.gov (United States)

Agarwal, Pooja K; Finley, Jason R; Rose, Nathan S; Roediger, Henry L

2017-07-01

We examined the effects of retrieval practice for students who varied in working memory capacity as a function of the lag between study of material and its initial test, whether or not feedback was given after the test, and the retention interval of the final test. We sought to determine whether a blend of these conditions exists that maximises benefits from retrieval practice for lower and higher working memory capacity students. College students learned general knowledge facts and then restudied the facts or were tested on them (with or without feedback) at lags of 0-9 intervening items. Final cued recall performance was better for tested items than for restudied items after both 10 minutes and 2 days, particularly for longer study-test lags. Furthermore, on the 2-day delayed test the benefits from retrieval practice with feedback were significantly greater for students with lower working memory capacity than for students with higher working memory capacity (r = -.42). Retrieval practice may be an especially effective learning strategy for lower ability students.

Hanford Waste Vitrification Plant capacity increase options

International Nuclear Information System (INIS)

Larson, D.E.

1996-04-01

Studies are being conducted by the Hanford Waste Vitrification Plant (HWVP) Project on ways to increase the waste processing capacity within the current Vitrification Building structural design. The Phase 1 study on remote systems concepts identification and extent of capacity increase was completed. The study concluded that the HWVP capacity could be increased to four times the current capacity with minor design adjustments to the fixed facility design, and the required design changes would not impact the current footprint of the vitrification building. A further increase in production capacity may be achievable but would require some technology development, verification testing, and a more systematic and extensive engineering evaluation. The primary changes included a single advance melter with a higher capacity, new evaporative feed tank, offgas quench collection tank, ejector venturi scrubbers, and additional inner canister closure station,a smear test station, a new close- coupled analytical facility, waste hold capacity of 400,000 gallon, the ability to concentrate out-of-plant HWVP feed to 90 g/L waste oxide concentration, and limited changes to the current base slab construction package

Predicting and mapping soil available water capacity in Korea.

Science.gov (United States)

Hong, Suk Young; Minasny, Budiman; Han, Kyung Hwa; Kim, Yihyun; Lee, Kyungdo

2013-01-01

The knowledge on the spatial distribution of soil available water capacity at a regional or national extent is essential, as soil water capacity is a component of the water and energy balances in the terrestrial ecosystem. It controls the evapotranspiration rate, and has a major impact on climate. This paper demonstrates a protocol for mapping soil available water capacity in South Korea at a fine scale using data available from surveys. The procedures combined digital soil mapping technology with the available soil map of 1:25,000. We used the modal profile data from the Taxonomical Classification of Korean Soils. The data consist of profile description along with physical and chemical analysis for the modal profiles of the 380 soil series. However not all soil samples have measured bulk density and water content at -10 and -1500 kPa. Thus they need to be predicted using pedotransfer functions. Furthermore, water content at -10 kPa was measured using ground samples. Thus a correction factor is derived to take into account the effect of bulk density. Results showed that Andisols has the highest mean water storage capacity, followed by Entisols and Inceptisols which have loamy texture. The lowest water retention is Entisols which are dominated by sandy materials. Profile available water capacity to a depth of 1 m was calculated and mapped for Korea. The western part of the country shows higher available water capacity than the eastern part which is mountainous and has shallower soils. The highest water storage capacity soils are the Ultisols and Alfisols (mean of 206 and 205 mm, respectively). Validation of the maps showed promising results. The map produced can be used as an indication of soil physical quality of Korean soils.

Predicting and mapping soil available water capacity in Korea

Directory of Open Access Journals (Sweden)

Suk Young Hong

2013-04-01

Full Text Available The knowledge on the spatial distribution of soil available water capacity at a regional or national extent is essential, as soil water capacity is a component of the water and energy balances in the terrestrial ecosystem. It controls the evapotranspiration rate, and has a major impact on climate. This paper demonstrates a protocol for mapping soil available water capacity in South Korea at a fine scale using data available from surveys. The procedures combined digital soil mapping technology with the available soil map of 1:25,000. We used the modal profile data from the Taxonomical Classification of Korean Soils. The data consist of profile description along with physical and chemical analysis for the modal profiles of the 380 soil series. However not all soil samples have measured bulk density and water content at −10 and −1500 kPa. Thus they need to be predicted using pedotransfer functions. Furthermore, water content at −10 kPa was measured using ground samples. Thus a correction factor is derived to take into account the effect of bulk density. Results showed that Andisols has the highest mean water storage capacity, followed by Entisols and Inceptisols which have loamy texture. The lowest water retention is Entisols which are dominated by sandy materials. Profile available water capacity to a depth of 1 m was calculated and mapped for Korea. The western part of the country shows higher available water capacity than the eastern part which is mountainous and has shallower soils. The highest water storage capacity soils are the Ultisols and Alfisols (mean of 206 and 205 mm, respectively. Validation of the maps showed promising results. The map produced can be used as an indication of soil physical quality of Korean soils.

MS PHD'S: Effective Strategies for the Retention and Advancement of URM Students in ESS

Science.gov (United States)

Escalera, J.; Burgess, A. K.; Pace, L.; Scott, O.; Strickland, J.; Johnson, A.; Williamson Whitney, V.; Ithier-Guzman, W.

2012-12-01

The Minorities Striving and Pursuing Higher Degrees of Success (MS PHD'S) Professional Development Program in Earth system science (ESS) is a model initiative for improving the retention of underrepresented minority (URM) students in STEM fields. Entering its ninth cohort, MS PHD'S remains committed to helping URM undergraduate and graduate students achieve outstanding careers in ESS. MS PHD'S facilitates URM student achievement through a three-phase program designed to increase student exposure to the ESS community. By engaging in a series of professional development and skill building exercises, peer-to-peer community building activities, participation in scientific society conferences and workshops, mentoring by URM and other scientists, and a virtual community, URM students gain the confidence and support necessary to achieve their academic goals and enter the ESS workforce. Since its inception, MS PHD'S continues to support 189 participants. Of these 189 participants, 35 have advanced from undergraduate and graduate academic pathways to completion of their PhD and another 60 are currently enrolled in doctoral programs. MS PHD'S maintains close ties with program alumni to further support retention, inclusivity, and broadening participation of URM students and graduates in STEM activities. Its model is built on reengaging alumni to become mentors and leaders for each new cohort as well as facilitating valuable opportunities for alumni to advance in their ESS related academic and professional career pathways.

An examination of factors impacting on talent retention at a financial institution

OpenAIRE

2015-01-01

M.Com. (Business Management) Talent commitment, efficiency and retention issues are emerging as the most important corporate challenges of the present and immediate future, driven by talent loyalty concerns, corporate reorganization efforts and stiff competition for key talent. For most organizations, “surprise” talent departures can be devastating on the execution of business strategy and the achievement of business goals and objectives. This phenomenon is most prevalent now in light of c...

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

Free-Space Optical Communications: Capacity Bounds, Approximations, and a New Sphere-Packing Perspective

KAUST Repository

Chaaban, Anas

2016-02-03

The capacity of the free-space optical channel is studied. A new recursive approach for bounding the capacity of the channel based on sphere-packing is proposed. This approach leads to new capacity upper bounds for a channel with a peak intensity constraint or an average intensity constraint. Under an average constraint only, the derived bound is tighter than an existing sphere-packing bound derived earlier by Farid and Hranilovic. The achievable rate of a truncated-Gaussian input distribution is also derived. It is shown that under both average and peak constraints, this achievable rate and the sphere-packing bounds are within a small gap at high SNR, leading to a simple high-SNR capacity approximation. Simple fitting functions that capture the best known achievable rate for the channel are provided. These functions can be of practical importance especially for the study of systems operating under atmospheric turbulence and misalignment conditions.

Free-Space Optical Communications: Capacity Bounds, Approximations, and a New Sphere-Packing Perspective

KAUST Repository

Chaaban, Anas; Morvan, Jean-Marie; Alouini, Mohamed-Slim

2016-01-01

The capacity of the free-space optical channel is studied. A new recursive approach for bounding the capacity of the channel based on sphere-packing is proposed. This approach leads to new capacity upper bounds for a channel with a peak intensity constraint or an average intensity constraint. Under an average constraint only, the derived bound is tighter than an existing sphere-packing bound derived earlier by Farid and Hranilovic. The achievable rate of a truncated-Gaussian input distribution is also derived. It is shown that under both average and peak constraints, this achievable rate and the sphere-packing bounds are within a small gap at high SNR, leading to a simple high-SNR capacity approximation. Simple fitting functions that capture the best known achievable rate for the channel are provided. These functions can be of practical importance especially for the study of systems operating under atmospheric turbulence and misalignment conditions.

On the Capacity Region of the Intensity-Modulation Direct-Detection Optical Broadcast Channel

KAUST Repository

Chaaban, Anas

2015-08-11

The capacity of the intensity-modulation direct-detection free-space optical broadcast channel (OBC) is investigated. The Gaussian model with input-independent Gaussian noise is used, with both average and peak intensity constraints. An outer bound on the capacity region is derived by adapting Bergmans\\' approach to the OBC. Inner bounds are derived by using superposition coding with either truncated-Gaussian distributions or discrete distributions. While the discrete input distribution achieves higher rates than the truncated-Gaussian distribution, the latter allows expressing the achievable rate region in a closed form. At high signal-to-noise ratio (SNR), it is shown that the truncated-Gaussian distribution is nearly optimal. It achieves the symmetric-capacity within a constant gap (independent of SNR), which approaches half a bit as the number of users grows large. It also achieves the capacity region within a constant gap, which depends on the number of users. At low SNR, it is shown that on-off keying with time-division multiple-access (TDMA) is optimal, as it achieves any point on the boundary of the developed outer bound. This is interesting in practice since both OOK and TDMA have low complexity. At moderate SNR (typically [0,8] dB), a discrete distribution with a small alphabet size achieves a fairly good performance in terms of symmetric rate.

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.

Regeneration limit of classical Shannon capacity

Science.gov (United States)

Sorokina, M. A.; Turitsyn, S. K.

2014-05-01

Since Shannon derived the seminal formula for the capacity of the additive linear white Gaussian noise channel, it has commonly been interpreted as the ultimate limit of error-free information transmission rate. However, the capacity above the corresponding linear channel limit can be achieved when noise is suppressed using nonlinear elements; that is, the regenerative function not available in linear systems. Regeneration is a fundamental concept that extends from biology to optical communications. All-optical regeneration of coherent signal has attracted particular attention. Surprisingly, the quantitative impact of regeneration on the Shannon capacity has remained unstudied. Here we propose a new method of designing regenerative transmission systems with capacity that is higher than the corresponding linear channel, and illustrate it by proposing application of the Fourier transform for efficient regeneration of multilevel multidimensional signals. The regenerative Shannon limit—the upper bound of regeneration efficiency—is derived.

The Role of Some Retention Aids in Water Based Gravure Printing

International Nuclear Information System (INIS)

El-Sherbiny, S.; Morsy, F.A.; Abdel- Sayed, E.S.

2005-01-01

Several commercial retention systems employing either synthetic or natural additives are now able to achieve an acceptable level of filler retention even during high speed paper forming. However, despite their importance, there have been very few reports in the literature regarding the influence of different retention aids on gravure water based ink printability. In the current work, a series of uncoated hand sheets containing the retention aids rosin aids rosin-alum, cationic starch, polyacrylamide and chitosan were prepared under controlled ph conditions. Chitosan is a natural additive only very recently employed in commercial papermaking systems. After printing with two water based ink systems, both printability and print quality were then assessed in terms of print density, gloss and ink transfer. The effect of surfactant addition to gravure water based ink was also studied. The results showed that the amount of ink transferred and the print density both decreased as the percentage of the selected additives increased. The addition of chitosan to the paper furnish led to a substantial decrease in both the amount of ink transferred and the print density compared to the other additives. Conversely, the presence of surfactant in the printing ink enhanced the print density and also increased the amount of ink transferred. In addition, results obtained demonstrated that printing with water based ink greatly decreased the print gloss in comparison to the paper gloss. Increasing the addition level of the selected additives led to an increase of print gloss due to a decrease in the amount of ink transferred. Increasing the ph of the pulp suspension containing 1 % of the selected additives increased the print density in all cases, except when using cationic starch

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.

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

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...

Policy Capacity for Health Reform: Necessary but Insufficient: Comment on "Health Reform Requires Policy Capacity".

Science.gov (United States)

Adams, Owen

2015-09-04

Forest and colleagues have persuasively made the case that policy capacity is a fundamental prerequisite to health reform. They offer a comprehensive life-cycle definition of policy capacity and stress that it involves much more than problem identification and option development. I would like to offer a Canadian perspective. If we define health reform as re-orienting the health system from acute care to prevention and chronic disease management the consensus is that Canada has been unsuccessful in achieving a major transformation of our 14 health systems (one for each province and territory plus the federal government). I argue that 3 additional things are essential to build health policy capacity in a healthcare federation such as Canada: (a) A means of "policy governance" that would promote an approach to cooperative federalism in the health arena; (b) The ability to overcome the "policy inertia" resulting from how Canadian Medicare was implemented and subsequently interpreted; and (c) The ability to entertain a long-range thinking and planning horizon. My assessment indicates that Canada falls short on each of these items, and the prospects for achieving them are not bright. However, hope springs eternal and it will be interesting to see if the July, 2015 report of the Advisory Panel on Healthcare Innovation manages to galvanize national attention and stimulate concerted action. © 2016 by Kerman University of Medical Sciences.

The Developmental Influence of Primary Memory Capacity on Working Memory and Academic Achievement

Science.gov (United States)

Hall, Debbora; Jarrold, Christopher; Towse, John N.; Zarandi, Amy L.

2015-01-01

In this study, we investigate the development of primary memory capacity among children. Children between the ages of 5 and 8 completed 3 novel tasks (split span, interleaved lists, and a modified free-recall task) that measured primary memory by estimating the number of items in the focus of attention that could be spontaneously recalled in…

Capacity analysis of spectrum sharing spatial multiplexing MIMO systems

KAUST Repository

Yang, Liang

2014-12-01

This paper considers a spectrum sharing (SS) multiple-input multiple-output (MIMO) system operating in a Rayleigh fading environment. First the capacity of a single-user SS spatial multiplexing system is investigated in two scenarios that assume different receivers. To explicitly show the capacity scaling law of SS MIMO systems, some approximate capacity expressions for the two scenarios are derived. Next, we extend our analysis to a multiple user system with zero-forcing receivers (ZF) under spatially-independent scheduling and analyze the sum-rate. Furthermore, we provide an asymptotic sum-rate analysis to investigate the effects of different parameters on the multiuser diversity gain. Our results show that the secondary system with a smaller number of transmit antennas Nt and a larger number of receive antennas Nr can achieve higher capacity at lower interference temperature Q, but at high Q the capacity follows the scaling law of the conventional MIMO systems. However, for a ZF SS spatial multiplexing system, the secondary system with small Nt and large Nr can achieve the highest capacity throughout the entire region of Q. For a ZF SS spatial multiplexing system with scheduling, the asymptotic sum-rate scales like Ntlog2(Q(KNtNp-1)/Nt), where Np denotes the number of antennas of the primary receiver and K represents the number of secondary transmitters.

Hierarchical Targeting Strategy for Enhanced Tumor Tissue Accumulation/Retention and Cellular Internalization.

Science.gov (United States)

Wang, Sheng; Huang, Peng; Chen, Xiaoyuan

2016-09-01

Targeted delivery of therapeutic agents is an important way to improve the therapeutic index and reduce side effects. To design nanoparticles for targeted delivery, both enhanced tumor tissue accumulation/retention and enhanced cellular internalization should be considered simultaneously. So far, there have been very few nanoparticles with immutable structures that can achieve this goal efficiently. Hierarchical targeting, a novel targeting strategy based on stimuli responsiveness, shows good potential to enhance both tumor tissue accumulation/retention and cellular internalization. Here, the recent design and development of hierarchical targeting nanoplatforms, based on changeable particle sizes, switchable surface charges and activatable surface ligands, will be introduced. In general, the targeting moieties in these nanoplatforms are not activated during blood circulation for efficient tumor tissue accumulation, but re-activated by certain internal or external stimuli in the tumor microenvironment for enhanced cellular internalization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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

Combining performance measures to investigate capacity changes in fisheries

DEFF Research Database (Denmark)

Thøgersen, Thomas Talund; Pascoe, Sean

2014-01-01

the actual fishing capacity. In both cases, the relationship between effort indicators and capacity needs to be resolved in order for the manager to introduce the right interventions. Previous studies have estimated these relationships in multi-species fisheries using either a multi-output distance function......The Common Fisheries Policy (CFP) aims to achieve a balance between the European fleet capacity and the resources available. This can be realized either by temporarily reducing the fishing effort (i.e. capacity utilization) or quotas in the hope of increasing the resources available or reducing...... catches of cod, plaice and Nephrops and that gross tonnage is a more consistent indicator of fishing capacity than engine power....

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.

Water retention and availability in soils of the State of Santa Catarina-Brazil: effect of textural classes, soil classes and lithology

Directory of Open Access Journals (Sweden)

André da Costa

2013-12-01

Full Text Available The retention and availability of water in the soil vary according to the soil characteristics and determine plant growth. Thus, the aim of this study was to evaluate water retention and availability in the soils of the State of Santa Catarina, Brazil, according to the textural class, soil class and lithology. The surface and subsurface horizons of 44 profiles were sampled in different regions of the State and different cover crops to determine field capacity, permanent wilting point, available water content, particle size, and organic matter content. Water retention and availability between the horizons were compared in a mixed model, considering the textural classes, the soil classes and lithology as fixed factors and profiles as random factors. It may be concluded that water retention is greater in silty or clayey soils and that the organic matter content is higher, especially in Humic Cambisols, Nitisols and Ferralsol developed from igneous or sedimentary rocks. Water availability is greater in loam-textured soils, with high organic matter content, especially in soils of humic character. It is lower in the sandy texture class, especially in Arenosols formed from recent alluvial deposits or in gravelly soils derived from granite. The greater water availability in the surface horizons, with more organic matter than in the subsurface layers, illustrates the importance of organic matter for water retention and availability.

Binders and Hosts for High-Capacity Lithium-ion Battery Anodes

Science.gov (United States)

Dufficy, Martin Kyle

Lithium-ion batteries (LIBs) are universal electrochemical energy storage devices that have revolutionized our mobile society. Nonetheless, societal and technological advances drive consumer demand for LIBs with enhanced electrochemical performance, such as higher charge capacity and longer life, compared to conventional LIBs. One method to enhance LIB performance is to replace graphite, the industry standard anode since commercialization of LIBs in 1991, with high-charge capacity materials. Implementing high-capacity anode materials such as tin, silicon, and manganese vanadates, to LIBs presents challenges; Li-insertion is destructive to anode framework, and increasing capacity increases structural strains that pulverize anode materials and results in a short-cycle life. This thesis reports on various methods to extended the cycle life of high-capacity materials. Most of the work is conducted on nano-sized anode materials to reduce Li and electron transport pathway length (facilitating charge-transfer) and reduce strains from volume expansions (preserving anode structure). The first method involves encapsulating tin particles into a graphene-containing carbon nanofiber (CNF) matrix. The composite-CNF matrix houses tin particles to assume strains from tin-volume expansions and produces favorable surface-electrolyte chemistries for stable charge-discharge cycling. Before tin addition, graphene-containing CNFs are produced and assessed as anode materials for LIBs. Graphene addition to CNFs improves electronic and mechanical properties of CNFs. Furthermore, the 2-D nature of graphene provides Li-binding sites to enhance composite-CNF both first-cycle and high-rate capacities > 150% when compared to CNFs in the absence of graphene. With addition of Sn, we vary loadings and thermal production temperature to elucidate structure-composition relationships of tin and graphene-containing CNF electrodes that lead to increased capacity retention. Of note, electrodes containing

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).

Utilizing Joint Routing and Capacity Assignment Algorithms to Achieve Inter- and Intra-Group Delay Fairness in Multi-Rate Multicast Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Yean-Fu Wen

2013-03-01

Full Text Available Recent advance in wireless sensor network (WSN applications such as the Internet of Things (IoT have attracted a lot of attention. Sensor nodes have to monitor and cooperatively pass their data, such as temperature, sound, pressure, etc. through the network under constrained physical or environmental conditions. The Quality of Service (QoS is very sensitive to network delays. When resources are constrained and when the number of receivers increases rapidly, how the sensor network can provide good QoS (measured as end-to-end delay becomes a very critical problem. In this paper; a solution to the wireless sensor network multicasting problem is proposed in which a mathematical model that provides services to accommodate delay fairness for each subscriber is constructed. Granting equal consideration to both network link capacity assignment and routing strategies for each multicast group guarantees the intra-group and inter-group delay fairness of end-to-end delay. Minimizing delay and achieving fairness is ultimately achieved through the Lagrangean Relaxation method and Subgradient Optimization Technique. Test results indicate that the new system runs with greater effectiveness and efficiency.

Retention of uranium(VI) by laumontite, a fracture-filling material of granite

International Nuclear Information System (INIS)

Baik, M.H.; Lee, S.Y.; Shon, W.J.

2009-01-01

Retention of U(VI) by laumontite, a fracture-filling material of granite as investigated by conducting dynamic and batch sorption experiments in a love-box using a granite core with a natural fracture. The hydrodynamic properties of the granite core were obtained from the elution curve of a on-sorbing tracer, Br - . The elution curve of U(VI) showed a similar behavior to Br - . This reveals that the retention of U(VI) by the fracture-filling material was not significant when migrating through the fracture at a given condition. From the dynamic sorption experiment, the retardation factor R a and the distribution coefficient K a of U(VI) were obtained as about 2.9 and 0.16 cm, respectively. The distribution coefficient K d ) of U(VI) onto laumontite obtained by conducting a batch sorption experiment resulted in a small value of 2.3±0.5 mL/g. This low K d value greed with the result of the dynamic sorption experiment. For the distribution of uranium on the granite surface investigated by an X-ray image mapping, the fracture region filled with laumontite showed a relatively lower content of uranium compared to the surrounding granite surface. Thus, the low retention of U(VI) by the fracture-filling material can be explained by following two mechanisms. One is that U(VI) exists as anionic uranyl hydroxides or uranyl carbonates at a given groundwater condition and the other is the remarkably low sorption capacity of the laumontite for U(VI). author)

Self-assembled Li3V2(PO4)3/reduced graphene oxide multilayer composite prepared by sequential adsorption

Science.gov (United States)

Kim, Myeong-Seong; Bak, Seong-Min; Lee, Suk-Woo; Cho, Byung-Won; Roh, Kwang Chul; Kim, Kwang-Bum

2017-11-01

Herein, we report on Li3V2(PO4)3 (LVP)/reduced graphene oxide (rGO) multilayer composites prepared via a sequential adsorption method and subsequent heat treatment, and their use as cathodes for high-rate lithium-ion batteries. The sequential adsorption process includes adsorbing oppositely charged components of anionic inorganic species and cationic head of a surfactant adsorbed to graphite oxide sheets, which is a key step in the fabrication of the LVP/rGO multilayer composites. The multilayer structure has open channels between the highly conductive rGO layers while achieving a relatively high tap density, which could effectively improve the rate capability. Consequently, the LVP/rGO multilayer composites exhibit a high tap density (0.6 g cm-3) and good electrochemical properties. Specifically, in the voltage range of 3.0-4.3 V, the composite exhibits a specific capacity of 131 mAh g-1 at 0.1C, a good rate capabilities (88% capacity retention at 60C), and long cycling performance (97% capacity retention after 500 cycles at 10C). Moreover, in the extended voltage range of 3.0-4.8 V, it exhibits a high specific capacity of 185 mAh g-1 at 0.2C, a good rate capability (66% capacity retention at 30C), and stable cycling performance (96% capacity retention after 500 cycles at 10C).

College Success: First Year Seminar's Effectiveness on Freshmen Academic and Social Integration, Impact on Academic Achievement and Retention at a Southern Institution

Science.gov (United States)

Malik, Tarun

2011-01-01

Increasing student retention and improving graduation rates continues to remain a critical issue for undergraduate institutions. Previous research suggests that student attrition is predominantly voluntary, and is influenced by institutional characteristics. The importance of academic and social integration as a strategy to reduce attrition is…

Enrofloxacin uptake and retention on different types of clays

Science.gov (United States)

Wan, Miao; Li, Zhaohiu; Hong, Hanlie; Wu, Qingfeng

2013-11-01

The adsorption and retention of enrofloxacin (EN) on different types of clays was studied in batch tests under different pH, contact time, and initial concentration conditions. XRD and FTIR analyses were utilized to characterize EN adsorption and to elucidate mechanisms of EN adsorption. The EN adsorption equilibrium followed the Langmuir isotherm and reached capacities of 667, 228 and 20 mmol/kg at pH 4-5 on the montmorillonite (SWy-2), illite (IMt-2), and kaolinite (KGa-1b), respectively. The pseudo-second-order model fitted the EN sorption kinetics well. Although EN had a much lower adsorption capacity on KGa-1b compared to that on the other two clays, the adsorption rate constant was the fastest at 0.73 kg/mmol-h. Cation exchange interaction was attributed to the major mechanism for EN adsorption on SWy-2 and IMt-2, and non-electrostatic interactions attributed to EN adsorption when solution pH was above 7. Intercalation of EN molecules into the interlayer space of SWy-2 was confirmed by the XRD patterns after EN adsorption. In contrast, the basal spacing and intensity remained the same after EN adsorption on IMt-2 and KGa-1b, indicating that the EN adsorption on the non-swelling clays were limited to the external surfaces.

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.

Capacity limits of spectrum-sharing systems over hyper-fading channels

KAUST Repository

Ekin, Sabit

2011-01-20

Cognitive radio (CR) with spectrum-sharing feature is a promising technique to address the spectrum under-utilization problem in dynamically changing environments. In this paper, the achievable capacity gain of spectrum-sharing systems over dynamic fading environments is studied. To perform a general analysis, a theoretical fading model called hyper-fading model that is suitable to the dynamic nature of CR channel is proposed. Closed-form expressions of probability density function (PDF) and cumulative density function (CDF) of the signal-to-noise ratio (SNR) for secondary users (SUs) in spectrum-sharing systems are derived. In addition, the capacity gains achievable with spectrum-sharing systems in high and low power regions are obtained. The effects of different fading figures, average fading powers, interference temperatures, peak powers of secondary transmitters, and numbers of SUs on the achievable capacity are investigated. The analytical and simulation results show that the fading figure of the channel between SUs and primary base-station (PBS), which describes the diversity of the channel, does not contribute significantly to the system performance gain. © 2011 John Wiley & Sons, Ltd.

Capacity limits of spectrum-sharing systems over hyper-fading channels

KAUST Repository

Ekin, Sabit; Yilmaz, Ferkan; Ç elebi, Hasari Burak; Qaraqe, Khalid A.; Alouini, Mohamed-Slim; Serpedin, Erchin

2011-01-01

Cognitive radio (CR) with spectrum-sharing feature is a promising technique to address the spectrum under-utilization problem in dynamically changing environments. In this paper, the achievable capacity gain of spectrum-sharing systems over dynamic fading environments is studied. To perform a general analysis, a theoretical fading model called hyper-fading model that is suitable to the dynamic nature of CR channel is proposed. Closed-form expressions of probability density function (PDF) and cumulative density function (CDF) of the signal-to-noise ratio (SNR) for secondary users (SUs) in spectrum-sharing systems are derived. In addition, the capacity gains achievable with spectrum-sharing systems in high and low power regions are obtained. The effects of different fading figures, average fading powers, interference temperatures, peak powers of secondary transmitters, and numbers of SUs on the achievable capacity are investigated. The analytical and simulation results show that the fading figure of the channel between SUs and primary base-station (PBS), which describes the diversity of the channel, does not contribute significantly to the system performance gain. © 2011 John Wiley & Sons, Ltd.

Battery designs with high capacity anode materials and cathode materials

Energy Technology Data Exchange (ETDEWEB)

Masarapu, Charan; Anguchamy, Yogesh Kumar; Han, Yongbong; Deng, Haixia; Kumar, Sujeet; Lopez, Herman A.

2017-10-03

Improved high energy capacity designs for lithium ion batteries are described that take advantage of the properties of high specific capacity anode active compositions and high specific capacity cathode active compositions. In particular, specific electrode designs provide for achieving very high energy densities. Furthermore, the complex behavior of the active materials is used advantageously in a radical electrode balancing design that significantly reduced wasted electrode capacity in either electrode when cycling under realistic conditions of moderate to high discharge rates and/or over a reduced depth of discharge.

Feed supplemented with byproducts from olive oil mill wastewater processing increases antioxidant capacity in broiler chickens.

Science.gov (United States)

Gerasopoulos, Konstantinos; Stagos, Dimitrios; Kokkas, Stylianos; Petrotos, Konstantinos; Kantas, Dimitrios; Goulas, Panagiotis; Kouretas, Dimitrios

2015-08-01

In the present study, a ceramic membrane microfiltration method was used for the separation of two liquid products, the downstream permeate and the upstream retentate, from olive mill wastewater (OMWW). These liquid products were examined for their antioxidant activity by incorporating them into broilers' feed. Twenty four broilers 13 d old were divided into two feeding groups receiving supplementation with OMWW retentate or permeate for 37 d. Blood was drawn at 17, 27 and 37 d, while tissues (muscle, heart, liver) were collected at 37 d. The antioxidant effects were assessed by measuring oxidative stress biomarkers in blood and tissues. The results showed that broilers given feed supplemented with OMWW retentate or permeate had significantly lower protein oxidation and lipid peroxidation levels and higher total antioxidant capacity in plasma and tissues compared to control group. In both OMWW groups, catalase activity in erythrocytes and tissues was significantly increased compared to control group. OMWW retentate administration increased significantly GSH in erythrocytes in broilers with low GSH, although both OMWW products significantly reduced GSH in broilers with high GSH. Thus, it has been demonstrated for the first time that supplementation with OMWW processing residues could be used for enhancing broilers' redox status. Copyright © 2015 Elsevier Ltd. All rights reserved.

Diffusion and retention of organic anions in Callovian-Oxfordian clay rock

International Nuclear Information System (INIS)

Rasamimanana, Sabrina

2016-01-01

The Callovo-Oxfordian mud-stone (CO_x) is studied as a possible host rock for a deep disposal of radioactive waste (Cigeo project). Indeed, besides being very weakly permeable, it presents a high content of clayey minerals, capable of retaining radionuclides under cationic form and to delay strongly their transport. Nevertheless, some waste packages may release a significant amount of organic molecules, capable of complexing these radionuclides and drastically increase their mobility. So, the objective of this work was to better understand the diffusive behavior of several organic molecules of interest in this mudstone, by investigating at first their affinity with the host rock. The retention of organic molecules under anionic form (acetate, phthalate, adipate, benzoate, and citrate) was quantified on to the dispersed CO_x mudstone using adsorption/desorption batch experiments. Experiments on de-carbonated rock and clay fraction only (≤ 2μm) were also performed to identify solid phases and chemical functions responsible for the retention. a correlation of the intensity of retention, R_d, was pointed out whit the dipole moment μ(Orga.), providing a qualitative estimate of retention capacity for polar hydrophilic organic molecules. So, phthalate, slightly polar, displays a reversible retention (R_d ≅1,6 L.kg"-"1), mainly on clayey phases. Citrate, very polar and strongly adsorbed (R_d ≅ 40 L.kg"-"1), displays a persistent desorption hysteresis and an affinity to different solid phases (clayey minerals and minor oxides). Lastly, acetate, adipate and benzoate, weakly polar, display a lower affinity with rock (R_d ≤ 0,2 L.kg"-"1). The diffusive behavior in compact rock of these organic anions was then studied. The effective diffusion coefficient and retardation factor values were quantified. The low diffusivity, [D_e/D_0](Organic Anions) ≅ 0,1 a0,25 * [D_e/D_0](Water) evidences an effect of anionic exclusion, with a same intensity as that observed for

High-capacity aqueous zinc batteries using sustainable quinone electrodes

Science.gov (United States)

Zhao, Qing; Huang, Weiwei; Luo, Zhiqiang; Liu, Luojia; Lu, Yong; Li, Yixin; Li, Lin; Hu, Jinyan; Ma, Hua; Chen, Jun

2018-01-01

Quinones, which are ubiquitous in nature, can act as sustainable and green electrode materials but face dissolution in organic electrolytes, resulting in fast fading of capacity and short cycle life. We report that quinone electrodes, especially calix[4]quinone (C4Q) in rechargeable metal zinc batteries coupled with a cation-selective membrane using an aqueous electrolyte, exhibit a high capacity of 335 mA h g−1 with an energy efficiency of 93% at 20 mA g−1 and a long life of 1000 cycles with a capacity retention of 87% at 500 mA g−1. The pouch zinc batteries with a respective depth of discharge of 89% (C4Q) and 49% (zinc anode) can deliver an energy density of 220 Wh kg−1 by mass of both a C4Q cathode and a theoretical Zn anode. We also develop an electrostatic potential computing method to demonstrate that carbonyl groups are active centers of electrochemistry. Moreover, the structural evolution and dissolution behavior of active materials during discharge and charge processes are investigated by operando spectral techniques such as IR, Raman, and ultraviolet-visible spectroscopies. Our results show that batteries using quinone cathodes and metal anodes in aqueous electrolyte are reliable approaches for mass energy storage. PMID:29511734

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.

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

Metal-ion retention properties of water-soluble amphiphilic block copolymer in double emulsion systems (w/o/w) stabilized by non-ionic surfactants.

Science.gov (United States)

Palencia, Manuel; Rivas, Bernabé L

2011-11-15

Metal-ion retention properties of water-soluble amphiphilic polymers in presence of double emulsion were studied by diafiltration. Double emulsion systems, water-in-oil-in-water, with a pH gradient between external and internal aqueous phases were prepared. A poly(styrene-co-maleic anhydride) (PSAM) solution at pH 6.0 was added to the external aqueous phase of double emulsion and by application of pressure a divalent metal-ion stream was continuously added. Metal-ions used were Cu(2+) and Cd(2+) at the same pH of polymer solution. According to our results, metal-ion retention is mainly the result of polymer-metal interaction. Interaction between PSMA and reverse emulsion globules is strongly controlled by amount of metal-ions added in the external aqueous phase. In addition, as metal-ion concentration was increased, a negative effect on polymer retention capacity and promotion of flocculation phenomena were produced. Copyright © 2011 Elsevier Inc. All rights reserved.

Retention in Differentiated Care: Multiple Measures Analysis for a Decentralized HIV Care and Treatment Program in North Central Nigeria

Science.gov (United States)

Agaba, Patricia A; Genberg, Becky L; Sagay, Atiene S; Agbaji, Oche O; Meloni, Seema T; Dadem, Nancin Y; Kolawole, Grace O; Okonkwo, Prosper; Kanki, Phyllis J; Ware, Norma C

2018-01-01

Objective Differentiated care refers collectively to flexible service models designed to meet the differing needs of HIV-infected persons in resource-scarce settings. Decentralization is one such service model. Retention is a key indicator for monitoring the success of HIV treatment and care programs. We used multiple measures to compare retention in a cohort of patients receiving HIV care at “hub” (central) and “spoke” (decentralized) sites in a large public HIV treatment program in north central Nigeria. Methods This retrospective cohort study utilized longitudinal program data representing central and decentralized levels of care in the Plateau State Decentralization Initiative, north central Nigeria. We examined retention with patient- level (retention at fixed times, loss-to-follow-up [LTFU]) and visit-level (gaps-in-care, visit constancy) measures. Regression models with generalized estimating equations (GEE) were used to estimate the effect of decentralization on visit-level measures. Patient-level measures were examined using survival methods with Cox regression models, controlling for baseline variables. Results Of 15,650 patients, 43% were enrolled at the hub. Median time in care was 3.1 years. Hub patients were less likely to be LTFU (adjusted hazard ratio (AHR)=0.91, 95% CI: 0.85-0.97), compared to spoke patients. Visit constancy was lower at the hub (−4.5%, 95% CI: −3.5, −5.5), where gaps in care were also more likely to occur (adjusted odds ratio=1.95, 95% CI: 1.83-2.08). Conclusion Decentralized sites demonstrated better retention outcomes using visit-level measures, while the hub achieved better retention outcomes using patient-level measures. Retention estimates produced by incorporating multiple measures showed substantial variation, confirming the influence of measurement strategies on the results of retention research. Future studies of retention in HIV care in sub-Saharan Africa will be well-served by including multiple measures

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...

Nitrogen retention in contrasting temperate forests exposed to high nitrogen deposition

Science.gov (United States)

Staelens, J.; Adriaenssens, S.; Wuyts, K.; Verheyen, K.; Boeckx, P. F.

2011-12-01

A better understanding of factors affecting nitrogen (N) retention is needed to assess the impact of changing anthropogenic N emissions and climatic conditions on N cycling and N loss by terrestrial ecosystems. Retention of N has been demonstrated for a wide range of forests, including ecosystems exposed to chronically enhanced N deposition, but it is still unclear which factors determine this N retention capacity. Therefore, we examined the possible effects of forest type on N retention using stable N isotopes. The study was carried out in adjacent equal-aged deciduous (pedunculate oak (Quercus robur L.)) and coniferous (Scots pine (Pinus sylvestris L.)) stands with a similar stand history and growing on a well-drained sandy soil in a region with enhanced N deposition (Belgium). The N input-output budgets and gross soil N transformation rates differed significantly between the two stands. The forest floor was exposed to a high inorganic N input from atmospheric deposition, which was nearly twice as high in the pine stand (33 ± 2 kg N ha-1 yr-1; mean ± standard error) as in the oak stand (18 ± 1 kg N ha-1 yr-1). The N input was reflected in the soil solution under the rooting zone, but the mean nitrate concentration was eight times higher under pine (19 ± 5 mg N L-1) than under oak (2.3 ± 0.9 mg N L-1). Gross N dynamics in the mineral topsoil were determined by in situ 15N labelling of undisturbed soil cores combined with numerical data analysis. Gross N mineralization was two times faster in the oak soil while nitrate production was two times faster in the pine soil, indicating a dominant effect of vegetation cover on soil N cycling. The higher gross nitrification, particularly due to oxidation of organic N, in the pine soil compared to the oak soil, combined with negligible nitrate immobilization, was in line with the higher nitrate leaching under the pine forest. On a larger spatial and temporal scale, the fate of dissolved inorganic N within these forests

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

Indicators of sustainable capacity building for health research: analysis of four African case studies.

Science.gov (United States)

Bates, Imelda; Taegtmeyer, Miriam; Squire, S Bertel; Ansong, Daniel; Nhlema-Simwaka, Bertha; Baba, Amuda; Theobald, Sally

2011-03-28

Despite substantial investment in health capacity building in developing countries, evaluations of capacity building effectiveness are scarce. By analysing projects in Africa that had successfully built sustainable capacity, we aimed to identify evidence that could indicate that capacity building was likely to be sustainable. Four projects were selected as case studies using pre-determined criteria, including the achievement of sustainable capacity. By mapping the capacity building activities in each case study onto a framework previously used for evaluating health research capacity in Ghana, we were able to identify activities that were common to all projects. We used these activities to derive indicators which could be used in other projects to monitor progress towards building sustainable research capacity. Indicators of sustainable capacity building increased in complexity as projects matured and included- early engagement of stakeholders; explicit plans for scale up; strategies for influencing policies; quality assessments (awareness and experiential stages)- improved resources; institutionalisation of activities; innovation (expansion stage)- funding for core activities secured; management and decision-making led by southern partners (consolidation stage).Projects became sustainable after a median of 66 months. The main challenges to achieving sustainability were high turnover of staff and stakeholders, and difficulties in embedding new activities into existing systems, securing funding and influencing policy development. Our indicators of sustainable capacity building need to be tested prospectively in a variety of projects to assess their usefulness. For each project the evidence required to show that indicators have been achieved should evolve with the project and they should be determined prospectively in collaboration with stakeholders.

The Limited Capacity of Sleep-Dependent Memory Consolidation

Directory of Open Access Journals (Sweden)

Gordon B Feld

2016-09-01

Full Text Available Sleep supports memory consolidation. However, the conceptually important influence of the amount of items encoded in a memory test on this effect has not been investigated. In two experiments, participants (n=101 learned lists of word-pairs varying in length (40, 160, 320 word-pairs in the evening before a night of sleep (sleep group or of sleep deprivation (wake group. After 36 h (including a night allowing recovery sleep retrieval was tested. Compared with wakefulness, post-learning sleep enhanced retention for the 160 word-pair condition (p < 0.01, importantly, this effect completely vanished for the 320 word-pair condition. This result indicates a limited capacity for sleep-dependent memory consolidation, which is consistent with an active system consolidation view on sleep’s role for memory, if it is complemented by processes of active forgetting and/or gist abstraction. Whereas the absolute benefit from sleep should have increased with increasing amounts of successfully encoded items, if sleep only passively protected memory from interference. Moreover, the finding that retention performance was significantly diminished for the 320 word-pair condition compared to the 160 word-pair condition in the sleep group, makes it tempting to speculate that with increasing loads of information encoded during wakefulness, sleep might favour processes of forgetting over consolidation.

Impact of biocrust succession on water retention and repellency on open-cast lignite mining sites under reclamation in Lower Lusatia, NE-Germany

Science.gov (United States)

Gypser, Stella; Fischer, Thomas; Lange, Philipp; Veste, Maik

2016-04-01

Mining activities can strongly affect ecosystem properties by destruction of naturally developed soils and removal of vegetation. The unstructured substrates show high bulk densities, compaction, low water infiltration rates, reduced water holding capacities and higher susceptibility to wind and water erosion. In the initial stage of the ecosystem development, the post-mining sites are open areas without or with a low cover of higher vegetation. It is well-known that biocrusts are able to colonize the soil surface under such extreme conditions without human support and affect soil hydrological processes such as water infiltration, run-off or re-distribution. Investigations were conducted on two former lignite open-cast mining sites, an artificial sand dune on the reclaimed watershed Welzow "Neuer Lugteich" and a reforestation area in Schlabendorf (Brandenburg, north-east Germany). The aim was to relate the hydrological characteristics of the topsoil to successional stages of biological soil crusts on reclaimed soils and their influence on repellency index and water holding capacity compared to pure mining substrate. Our study emphasized the influence of changing successional stages and species composition of biological soil crusts, forming a small-scale crust pattern, on water repellency and retention on sandy soils in temperate climate. Different successional stages of soil crusts were identified from initial scattered green algae crusts, dominated by Zygogonium spec. and Ulothrix spec., and more developed soil crusts containing mosses such as Ceratodon purpureus and Polytrichum piliferum. Lichens of the Genus Cladonia were more pronouncedly contributed to biocrusts at later and mature stages of development. The repellency index on the one hand increased due to the cross-linking of sand particles by the filamentous green algae Zygogonium spec. which resulted in clogging of pores, and on the other hand decreased with the occurrence of moss plants due to absorption

MIMO channel capacity with full CSI at Low SNR

KAUST Repository

Tall, Abdoulaye

2012-10-01

In this paper, we characterize the ergodic capacity of Multiple Input Multiple Output (MIMO) Rayleigh fading channels with full channel state information (CSI) at both the transmitter (CSI-T) and the receiver (CSI-R) at asymptotically low signal-to-noise ratio (SNR). A simple analytical expression of the capacity is derived for any number of transmit and receive antennas. This characterization clearly shows the substantial gain in terms of capacity over the no CSI-T case and gives a good insight on the effect of the number of antennas used. In addition, an On-Off transmission scheme is proposed and is shown to be asymptotically capacity-achieving. © 2012 IEEE.

Community capacity building and sustainability: outcomes of community-based participatory research.

Science.gov (United States)

Hacker, Karen; Tendulkar, Shalini A; Rideout, Catlin; Bhuiya, Nazmim; Trinh-Shevrin, Chau; Savage, Clara P; Grullon, Milagro; Strelnick, Hal; Leung, Carolyn; DiGirolamo, Ann

2012-01-01

For communities, the value of community-based participatory research (CBPR) is often manifested in the outcomes of increased capacity and sustainable adoption of evidence-based practices for social change. Educational opportunities that promote discourse between community and academic partners can help to advance CBPR and better define these outcomes. This paper describes a community-academic conference to develop shared definitions of community capacity building and sustainability related to CBPR and to identify obstacles and facilitators to both. "Taking It to the Curbside: Engaging Communities to Create Sustainable Change for Health" was planned by five Clinical Translational Science Institutes and four community organizations. After a keynote presentation, breakout groups of community and academic members met to define community capacity building and sustainability, and to identify facilitators and barriers to achieving both. Groups were facilitated by researcher-community partner teams and conversations were recorded and transcribed. Qualitative analysis for thematic content was conducted by a subset of the planning committee. Important findings included learning that (1) the concepts of capacity and sustainability were considered interconnected; (2) partnership was perceived as both a facilitator and an outcome of CBPR; (3) sustainability was linked to "transfer of knowledge" from one generation to another within a community; and (4) capacity and sustainability were enhanced when goals were shared and health outcomes were achieved. Community capacity building and sustainability are key outcomes of CBPR for communities. Co-learning opportunities that engage and mutually educate both community members and academics can be useful strategies for identifying meaningful strategies to achieve these outcomes.

U.S. Public Administration Programs: Increasing Academic Achievement by Identifying and Utilizing Student Learning Styles

Science.gov (United States)

Naylor, Lorenda A; Wooldridge, Blue; Lyles, Alan

2014-01-01

Global economic shifts are forcing universities to become more competitive and operationally efficient. As a result, universities emphasize access, affordability, and achievement. More specifically, U.S. universities have responded by emphasizing course assessment, retention rates, and graduation rates. Both university administrators and faculty…

The ımpact of benefıts and servıces on manager engagement and manager retentıon ın tourısm ındustry: Enhanced by the effect of management level

OpenAIRE

ALDATMAZ, Ipek; AYKAÇ, Cansu; DICLE, Ülkü

2017-01-01

Manager engagement and retention are vital to the success and organizational performance of many service sector organisations. Maintaining manager retention is a major challenge that many hotel enterprises face today. It is critical that organizations give greater importance to manager engagement, motivation and retention and therefore establish an efficient benefits and services strategy for retaining these core managers for the persistence and achievement of the organization...

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

USE OF STRONG ACID RESIN PUROLITE C100E FOR REMOVING PERMANENT HARDNESS OF WATER – FACTORS AFFECTING CATIONIC EXCHANGE CAPACITY

Directory of Open Access Journals (Sweden)

BOGDAN BANDRABUR

2013-12-01

Full Text Available This paper experimentally investigates the performance and capacity of Purolite C100E commercial resin recommended for water softening applications in the food industry. The practical ion exchange capacity and the softening process efficiency are studied in batch mode as a function of the sorption specific process factors. Optimum operation conditions were determined as initial pH 7.1, resin dose 8 g dry resin•L-1, temperature 25 oC, contact time of 360 min, and in those conditions the retention capacity for the Ca2+ ions is 17.18 mg•g-1 that corresponds to a removal efficiency equal to 85.7%.

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.

Effectiveness of creative and productive instructional method towards students' learning achievement in steel structure course

Science.gov (United States)

Sugiyanto, Pribadi, Supriyanto, Bambang

2017-09-01

The purpose of this study was to investigate the effectiveness of Creative & Productive instructional method compared with conventional method. This research was a quasi-experimental study involving all Civil Engineering students at Universitas Negeri Malang who were taking a course of Steel Structure. The students were randomly assigned to two different treatment groups, 30 students in experimental group and 37 students in the control group. It was assumed that these groups were equal in all relevant aspects; they differed only in the treatment administered. We used the t-test to test the hypothesis. The results of this research suggest that: (l) the use of Creative & Productive instructional method can significantly improve students' learning achievement, (2) the use of Creative & Productive instructional method can significantly improve students' retention, (3) students' motivation has a significant effect on their learning achievement, and (4) students' motivation has a significant effect on their retention.

The Effect of Secondary School Study Skills Preparation on First-Year University Achievement

Science.gov (United States)

Jansen, Ellen P. W. A.; Suhre, Cor J. M.

2010-01-01

Although many studies have revealed the importance of study skills for students' first-year performance and college retention, the extent of the impact of study skills preparation on students' academic achievement is less clear. This paper explores the impact of pre-university study skills preparation on students' first-year study experiences,…

Human resource management strategies for the retention of nurses in acute care settings in hospitals in Australia.

Science.gov (United States)

Hogan, Pamela; Moxham, Lorna; Dwyer, Trudy

2007-04-01

It is paramount that there is an adequate nursing workforce supply for now and in the future, to achieve equitable and quality health outcomes and consumer access to healthcare, regardless of geographic location. Nursing forms the largest body of employees in the health care system, spanning all segments of care. A shortage of nurses, particularly in the acute care settings in hospitals, jeopardizes the provision of quality health care to consumers. This article provides a literature review of Australian State and Federal Government reports into nurse retention. All reports discuss staff turnover rates; the average age of nurses; enrolment numbers in nursing courses; workloads; nursing workforce shortfalls and the effect on the work environment; leadership and management styles; organizational culture; change management; the mobility of nursing qualifications both locally and internationally and the critical need to value nurses. Then why has the situation of nurse retention not improved? Possible reasons for the continued nurse shortage and the promise of strategic HRM in addressing nurse retention are discussed.

Colloidal suspensions hydrodynamic retention mechanisms in model porous media; Mecanismes de retention hydrodynamique de suspensions colloidales en milieux poreux modeles

Energy Technology Data Exchange (ETDEWEB)

Salehi, N

1996-04-19

This study deals with the retention mechanisms of colloidal particles in porous media flows, and the subsequent reduction in permeability in the case of stable and non adsorbing colloids. It combines experimental results and modelling. This study has been realised with stable dispersion of monodispersed carboxylate polystyrene latexes negatively charged injected through negatively charged polycarbonate membranes having mono-sized cylindrical pores. The mean particle diameter is smaller than the mean pore diameter. Both batch and flow experiments in Nuclepore membranes have been done. The results of batch experiments have proved no adsorption of the colloidal latex particles on the surface of the Nuclepore membranes without flow at low salinity. In flow experiments at low particle concentration, only deposition on the upstream side of the membrane have been induced by hydrodynamic forces even for non adsorbing particles without creating any permeability reduction. The retention levels are zero at low and high Peclet numbers with a maximum at intermediate values. Partial plugging was observed at higher colloid concentration even at low salinity without any upstream surface deposition. The modelling of plugging processes is achieved by considering the particle concentration, fluid rate and ratio between the mean pore diameter and the mean particle diameter. This study can be particularly useful in the fields of water treatment and of restoration of lands following radioactive contamination. (author). 96 refs., 99 figs., 29 tabs.

Effect of damage on water retention and gas transport properties geo-materials: Application to geological storage of radioactive waste

International Nuclear Information System (INIS)

M'Jahad, S.

2012-01-01

In the context of geological disposal of radioactive waste, this work contributes to the characterization of the effect of diffuse damage on the water retention and gas transfer properties of concrete (CEM I and CEM V) selected by Andra, Callovo-Oxfordian argillite (host rock) and argillite / concrete interfaces. This study provides information on the concrete microstructure from Mercury porosimetry intrusion and water retention curves: each concrete has a distinct microstructure, CEM I concrete is characterized by a significant proportion of capillary pores while CEM V concrete has a large proportion of C-S-H pores. Several protocols have been developed in order to damage concrete. The damage reduces water retention capacity of CEM I concrete and increases its gas permeability. Indeed, gas breakthrough pressure decreases significantly for damaged concrete, and this regardless of the type of concrete. For argillite, the sample mass increases gradually at RH = 100%, which creates and increases damage in the material. This reduces its ability to retain water. Otherwise, water retention and gas transport properties of argillite are highly dependent of its initial water saturation, which is linked to its damage. Finally, we observed a clogging phenomenon at the argillite/concrete interfaces, which is first mechanical and then hydraulic (and probably chemical) after water injection. This reduces the gas breakthrough pressure interfaces. (author)

Three-Way Channels With Multiple Unicast Sessions: Capacity Approximation via Network Transformation

KAUST Repository

Chaaban, Anas

2016-09-28

A network of three nodes mutually communicating with each other is studied. This multi-way network is a suitable model for three-user device-to-device communications. The main goal of this paper is to characterize the capacity region of the underlying Gaussian three-way channel (3WC) within a constant gap. To this end, a capacity outer bound is derived using cut-set bounds and genie-aided bounds. For achievability, the 3WC is first transformed into an equivalent star channel. This latter is then decomposed into a set of “successive” sub-channels, leading to a sub-channel allocation problem. Using backward decoding, interference neutralization, and known results on the capacity of the star-channel relying of physical-layer network coding, an achievable rate region for the 3WC is obtained. It is then shown that the achievable rate region is within a constant gap of the developed outer bound, leading to the desired capacity approximation. Interestingly, in contrast to the Gaussian two-way channel (TWC), adaptation is necessary in the 3WC. Furthermore, message splitting is another ingredient of the developed scheme for the 3WC, which is not required in the TWC. The two setups are, however, similar in terms of their sum-capacity pre-log, which is equal to 2. Finally, some interesting networks and their approximate capacities are recovered as special cases of the 3WC, such as the cooperative broadcast channel and multiple access channel.

Soil moisture retention and mass movement of volcanic soils from the “Sabinas” sector in Caldas, Colombia

OpenAIRE

William Chavarriaga Montoya; Josè Gabriel Cruz Cerón; Johan Cuervo Correa

2017-01-01

The mass movement of soils, are soil, rocks displacements or both, caused by soil water excesses in terrains due to gravity effects and other factors. The aim of this research was to quantify the moisture retention capacity of volcanic soils as a threat indicator in the mass removal phenomena. This research was carried out on soils of the Malteria - Las Margaritas road transept to Magdalena river, right bank of the Chinchiná river in the Department of Caldas, Colombia. Through soil sample des...

Low-SNR Capacity of Parallel IM-DD Optical Wireless Channels

KAUST Repository

Chaaban, Anas

2016-11-29

The capacity of parallel intensity-modulation and direct-detection (IM-DD) optical wireless channels with total average intensity and per-channel peak intensity constraints is studied. The optimal intensity allocation at low signal-to-noise ratio (SNR) is derived, leading to the capacity-achieving onoff keying (OOK) distribution. Interestingly, while activating the strongest channel is optimal if (i) the peak intensity is fixed, this is not the case if (ii) the peak intensity is proportional to the average intensity. The minimum average optical intensity per bit is also studied, and is characterized for case (i) where it is achievable at low SNR. However, in case (ii), the average optical intensity per bit grows indefinitely as SNR decreases, indicating that lower optical intensity per bit can be achieved at moderate SNR than at low SNR.

Biochar impact on improving root growth and water retention capacity in Norfolk hard setting subsoil layer

Science.gov (United States)

The Norfolk soil series is a well-drained soil used commonly for agricultural production in the Eastern Carolinas. Certain profile features such as a hard setting subsoil layer with high bulk density, low water holding capacity and meager soil fertility characteristics makes this soil less producti...

The Retention of Female Unrestricted Line Officers

National Research Council Canada - National Science Library

Pecenco, Elena G

2005-01-01

This thesis analyzes the retention of female Naval officers, focusing on the relationship between officer selection metrics and retention beyond minimum service obligation and the effect of lateral...

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

Directory of Open Access Journals (Sweden)

Hadi Falahati

2017-09-01

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

12 CFR 609.945 - Records retention.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Records retention. 609.945 Section 609.945 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM ELECTRONIC COMMERCE Standards for Boards and Management § 609.945 Records retention. Records stored electronically must be accurate, accessible...

Employee Retention Strategies And Organizational Performance ...

African Journals Online (AJOL)

Implication of the results for practice is that any organization that fails to put in place adequate employee retention strategies is not likely to retain competent and motivated workforce in its employment and hence experience frequent labour turnover and poor organizational performance. Keywords: Employees, Retention ...

African Retentions in Blues and Jazz.

Science.gov (United States)

Meadows, Eddie S.

1979-01-01

The perseverance of African musical characteristics among American Blacks is an historic reality. African retentions have been recorded in Black music of the antebellum period. Various African scales and rhythms permeate Black American music today as evidenced in the retentions found in blues and jazz. (RLV)

Emotional Intelligence and Nursing Student Retention

Science.gov (United States)

Wilson, Victoria Jane

2013-01-01

The study examined the constructs of a Multi-Intelligence Model of Retention with four constructs: cognitive and emotional-social intelligence, student characteristics, and environmental factors. Data were obtained from sophomore students entering two diploma, nine associate, and five baccalaureate nursing programs. One year later, retention and…

Redesigning Schools to Raise Achievement. Item Number 39-0464

Science.gov (United States)

American Federation of Teachers, 2003

2003-01-01

The primary goal of the American Federation of Teachers' (AFT) Redesigning Schools to Raise Achievement (RSRA) project is to build capacity at the state, district, school, and classroom levels to improve student achievement to meet the goals of the 2001 No Child Left Behind Act. This checklist highlights some of the opportunities and support…

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 ...

On the Secrecy Capacity of MISO Visible Light Communication Channels

KAUST Repository

Arfaoui, Mohamed Amine

2017-02-07

We study the secrecy capacity of the multiple- input single-output (MISO) Gaussian wiretap visible light communication (VLC) channel. We study a typical VLC scenario with one transmitter, one legitimate receiver, and one eavesdropper. Specifically, we compute the achievable secrecy rate for various input signaling distributions, including the truncated generalized normal (TGN) and uniform distributions. The transmitter is equipped with multiple light sources, while the legitimate and unauthorized receivers are each equipped with a single photodetector. We analyze the achievable secrecy rates via transmit beamforming and artificial noise. In addition, both zero-forcing beamforming and robust beamforming are considered. In the former case, the location of the eavesdropper is assumed to be known, whereas in the latter case, the location of the eavesdropper is unknown. Our numerical results show that the secrecy rate achieved by the TGN distribution is significantly improved as compared to those achieved by the truncated Gaussian and uniform distributions, for both zero-forcing beamforming and robust beamforming. We also derive an upper bound on the achievable secrecy capacity that we used to assess the closeness of the achievable secrecy rates to the derived bound.

Factors That Influence Enrolment and Retention in Ghana’ National Health Insurance Scheme

Science.gov (United States)

Millicent Kotoh, Agnes; Aryeetey, Genevieve Cecilia; der Geest, Sjaak Van

2018-01-01

Background: The government of Ghana introduced the National Health Insurance Scheme (NHIS) in 2004 with the goal of achieving universal coverage within 5 years. Evidence, however, shows that expanding NHIS coverage and especially retaining members have remained a challenge. A multilevel perspective was employed as a conceptual framework and methodological tool to examine why enrolment and retention in the NHIS remains low. Methods: A household survey was conducted after 20 months educational and promotional activities aimed at improving enrolment and retention rates in 15 communities in the Central and Eastern Regions (ERs) of Ghana. Observation, indepth interviews and informal conversations were used to collect qualitative data. Forty key informants (community members, health providers and district health insurance schemes’ [DHISs] staff) purposely selected from two casestudy communities in the Central Region (CR) were interviewed. Several community members, health providers and DHISs’ staff were also engaged in informal conversations in the other five communities in the region. Also, four staff of the Ministry of Health (MoH), Ghana Health Service (GHS) and National Health Insurance Authority (NHIA) were engaged in in-depth interviews. Descriptive statistics was used to analyse quantitative data. Qualitative data was analysed using thematic content analysis. Results: The results show that factors that influence enrolment and retention in the NHIS are multi-dimensional and cut across all stakeholders. People enrolled and renewed their membership because of NHIS’ benefits and health providers’ positive behaviour. Barriers to enrolment and retention included: poverty, traditional risk-sharing arrangements influence people to enrol or renew their membership only when they need healthcare, dissatisfaction about health providers’ behaviour and service delivery challenges. Conclusion: Given the multi-dimensional nature of barriers to enrolment and retention

Retention of airborne particles in granular bed filters

International Nuclear Information System (INIS)

Stroem, L.

1981-01-01

A literature survey was made on theoretical models for the prediction of particle retention in sand beds. Also data on observed retention was collected from the literature. Based on this information, a semi-empirical model was compiled. Comparison of the model with published retention data shows a general agreement. (Auth.)

On the ergodic secret message capacity of the wiretap channel with finite-rate feedback

KAUST Repository

Rezki, Zouheir

2012-07-01

We study the secret message capacity of an ergodic block fading wiretap channel with partial channel state information at the transmitter and perfect channel state information at the receivers. We consider that in addition to the statistics of the main and the eavesdropper channel state information (CSI), the sender is provided by the legitimate receiver with a q-bit feedback, at the beginning of each coherence block, through an error-free feedback channel, with capacity q bits. We establish upper and lower bounds on the secrecy capacity. We show that a positive secrecy rate is achievable even when the feedback is at the end of each coherence block and q = 1. We also show that the lower and the upper bounds coincide asymptotically as q → ∞. Finally, asymptotic analysis at high Signal-to-Noise Ratio (SNR) are presented where it is found that the capacity is bounded at high-SNR and present a simple suboptimal scalar quantizer that is capacity achieving, without the need of any numerical optimization, as q → ∞. When applied to Rayleigh fading channels, we show that, at high-SNR, a 4-bit feedback achieves 90% of the secrecy capacity when perfect main CSI is available at the transmitter. © 2012 IEEE.

On the ergodic secret message capacity of the wiretap channel with finite-rate feedback

KAUST Repository

Rezki, Zouheir; Khisti, Ashish J.; Alouini, Mohamed-Slim

2012-01-01

We study the secret message capacity of an ergodic block fading wiretap channel with partial channel state information at the transmitter and perfect channel state information at the receivers. We consider that in addition to the statistics of the main and the eavesdropper channel state information (CSI), the sender is provided by the legitimate receiver with a q-bit feedback, at the beginning of each coherence block, through an error-free feedback channel, with capacity q bits. We establish upper and lower bounds on the secrecy capacity. We show that a positive secrecy rate is achievable even when the feedback is at the end of each coherence block and q = 1. We also show that the lower and the upper bounds coincide asymptotically as q → ∞. Finally, asymptotic analysis at high Signal-to-Noise Ratio (SNR) are presented where it is found that the capacity is bounded at high-SNR and present a simple suboptimal scalar quantizer that is capacity achieving, without the need of any numerical optimization, as q → ∞. When applied to Rayleigh fading channels, we show that, at high-SNR, a 4-bit feedback achieves 90% of the secrecy capacity when perfect main CSI is available at the transmitter. © 2012 IEEE.

Black Student Retention in Higher Education.

Science.gov (United States)

Lang, Marvel, Ed.; Ford, Clinita A., Ed.

This collection focuses on problems in the recruitment, enrollment and retention of Blacks in higher education in America. The following chapters are provided: "The Black Student Retention Problem in Higher Education: Some Introductory Perspectives" (Marvel Lang); "Early Acceptance and Institutional Linkages in a Model Program of Recruitment,…

Minority Teacher Recruitment and Retention Strategies

Science.gov (United States)

Kearney-Gissendaner, Janet E.

2010-01-01

The tools and resources in this book help school leaders seamlessly incorporate minority teacher recruitment and retention programs into current human-resources activities. With details about exemplary minority teacher recruitment and retention programs, this book also showcases strategies for how to replicate such programs in your own school or…

The Approximate Capacity Region of the Symmetric $K$-user Gaussian Interference Channel with Strong Interference

KAUST Repository

Chaaban, Anas

2016-03-01

The symmetric K-user interference channel is studied with the goal of characterizing its capacity region in the strong interference regime within a constant gap. The achievable rate region of a scheme combining rate-splitting at the transmitters and interference alignment and successive decoding/computation at the receivers is derived. Next it is shown that this scheme achieves the so-called greedy-max corner points of the capacity region within a constant gap. By combining this result with previous results by Ordentlich et al. on the sum-capacity of the symmetric interference channel, a constant gap characterization of the capacity region for the strong interference regime is obtained. This leads to the first approximate characterization of the capacity region of the symmetric K-user IC. Furthermore, a new scheme that achieves the sum-capacity of the channel in the strong interference regime within a constant gap is also proposed, and the corresponding gap is calculated. The advantage of the new scheme is that it leads to a characterization within a constant gap without leaving an outage set contrary to the scheme by Ordentlich et al..

The Approximate Capacity Region of the Symmetric $K$-user Gaussian Interference Channel with Strong Interference

KAUST Repository

Chaaban, Anas; Sezgin, Aydin

2016-01-01

The symmetric K-user interference channel is studied with the goal of characterizing its capacity region in the strong interference regime within a constant gap. The achievable rate region of a scheme combining rate-splitting at the transmitters and interference alignment and successive decoding/computation at the receivers is derived. Next it is shown that this scheme achieves the so-called greedy-max corner points of the capacity region within a constant gap. By combining this result with previous results by Ordentlich et al. on the sum-capacity of the symmetric interference channel, a constant gap characterization of the capacity region for the strong interference regime is obtained. This leads to the first approximate characterization of the capacity region of the symmetric K-user IC. Furthermore, a new scheme that achieves the sum-capacity of the channel in the strong interference regime within a constant gap is also proposed, and the corresponding gap is calculated. The advantage of the new scheme is that it leads to a characterization within a constant gap without leaving an outage set contrary to the scheme by Ordentlich et al..

Water absorption, retention and the swelling characteristics of cassava starch grafted with polyacrylic acid.

Science.gov (United States)

Witono, J R; Noordergraaf, I W; Heeres, H J; Janssen, L P B M

2014-03-15

An important application of starch grafted with copolymers from unsaturated organic acids is the use as water absorbent. Although much research has been published in recent years, the kinetics of water absorption and the swelling behavior of starch based superabsorbents are relatively unexplored. Also, water retention under mechanical strain is usually not reported. Cassava starch was used since it has considerable economic potential in Asia. The gelatinized starch was grafted with acrylic acid and Fenton's initiator and crosslinked with N,N'-methylenebisacrylamide (MBAM). Besides a good initial absorption capacity, the product could retain up to 63 g H2O/g under severe suction. The material thus combines a good absorption capacity with sufficient gel strength. The mathematical analysis of the absorption kinetics shows that at conditions of practical interest, the rate of water penetration into the gel is determined by polymer chain relaxations and not by osmotic driven diffusion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Should fully autonomous artificial intelligence systems be granted legal capacity?

OpenAIRE

Naučius, Mindaugas

2018-01-01

The aim of this article is to address the issue of granting legal capacity to artificial inteligence systems. In order to approach the solution to the problem addressed, the article includes several aspects, relevant in order to achieve it. To begin with, the general concept of legal capacity is introduced. Following this aspect, the main features of both natural and juridical persons are addressed, in order to become familiar with the content of legal capacity, or in other words, to be aware...

Flavor Dependent Retention of Remote Food Preference Memory.

Science.gov (United States)

Singh, Aditya; Kumar, Suraj; Singh, Vikram Pal; Das, Asish; Balaji, J

2017-01-01

Social Transmission of Food Preference (STFP) is a single trial non-aversive learning task that is used for testing non-spatial memory. This task relies on an accurate estimate of a change in food preference of the animals following social demonstration of a novel flavor. Conventionally this is done by providing two flavors of powdered food and later estimating the amount of food consumed for each of these flavors in a defined period of time. This is achieved through a careful measurement of leftover food for each of these flavors. However, in mice, only a small (~1 g) amount of food is consumed making the weight estimates error prone and thereby limiting the sensitivity of the paradigm. Using multiplexed video tracking, we show that the pattern of consumption can be used as a reliable reporter of memory retention in this task. In our current study, we use this as a measure and show that the preference for the demonstrated flavor significantly increases following demonstration and the retention of this change in preference during remote testing is flavor specific. Further, we report a modified experimental design for performing STFP that allows testing of change in preference among two flavors simultaneously. Using this paradigm, we show that during remote testing for thyme and basil demonstrated flavors, only basil demonstrated mice retain the change in preference while thyme demonstrated mice do not.

Supporting Capacity Development for Sustainable Land Administration Infrastructures

DEFF Research Database (Denmark)

Enemark, Stig

2005-01-01

and for identifying an adequate response to these needs at societal, organisational and individual levels. The paper examines the capacity building concept and underpins the need for institutional development to facilitate the design and implementation of efficient Land Administration Models and to support good......Land management is the process by which the resources of land are put into good effect. Land management encompasses all activities associated with the management of land and natural resources that are required to achieve sustainable development. Land Administration Systems are institutional......, the national capacity to manage land rights, restrictions and responsibilities is not well developed in terms of mature institutions and the necessary human resources and skills. In this regard, the capacity building concept offers some guidance for analysing and assessing the capacity needs...

Restoration of stormwater retention capacity at the allotment-scale through a novel economic instrument.

Science.gov (United States)

Fletcher, Tim D; Walsh, Chistopher J; Bos, Darren; Nemes, Veronika; RossRakesh, Sharyn; Prosser, Toby; Hatt, Belinda; Birch, Rhiannon

2011-01-01

Urbanisation results in changes to runoff behaviour which, if not addressed, inevitably degrade receiving waters. To date, most stormwater management has focussed on the streetscape and public open space. Given that much of the catchment imperviousness is located on private land, we developed and tested a novel economic instrument (a uniform price auction) for encouraging allotment-scale stormwater retention. We evaluated bids using an integrated environmental benefit index (EBI), based on the ability of the proposed works to reduce runoff frequency, pollutant loads and to reduce potable water demand. The uniform price auction resulted in 1.4 ha of impervious areas being effectively 'disconnected' from the stormwater system. The EBI provided an objective and transparent method of comparing bids, which varied in the type of works proposed (e.g. rainwater tank, rain-garden), the cost and the resulting environmental benefit. Whilst the pilot auction was a success, the public subsidy of works undertaken was around 85%, meaning that property owners a relatively small private benefit in the works. Future auction rounds will be revised to (i) test an EBI which is more focussed on the protection of streams (assessing changes to runoff frequency, baseflow volumes and water quality) and (ii) provide an auction process which is simpler to understand, and provides greater practical support for landholders who wish to undertake works.

76 FR 34010 - Credit Risk Retention

Science.gov (United States)

2011-06-10

... 2501-AD53 Credit Risk Retention AGENCIES: Office of the Comptroller of the Currency, Treasury (OCC... credit risk retention requirements of section 15G of the Securities Exchange Act of 1934, as added by the Dodd-Frank Wall Street Reform and Consumer Protection Act (``Credit Risk NPR'' or ``proposed rule...

A Study of Perceived Admission and Achievement Barriers of Learning-Disabled Students in Postsecondary Institutions

Science.gov (United States)

Lamberg, Catherine Denise

2012-01-01

Learning-disabled students face ongoing challenges in higher education. Despite efforts to promote recruitment and retention of students with learning disabilities to trade schools, colleges, and universities, barriers to enrollment and academic achievement persist. Barriers for learning-disabled students are not fully understood and might be…

The Effects of Elaboration and Rehearsal on Long-Term Retention of Shape Names by Kindergarteners. Technical Report #31.

Science.gov (United States)

Gallimore, Ronald; And Others

This paper examines the use of elaboration and overt rehearsal as strategies for increasing kindergarten children's retention and recall of shape names. The study is part of a large scale investigation concerned with improving the school achievement of Hawaiian and part-Hawaiian children. Twenty-four kindergarten children enrolled in a…

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…

Investigation of the variation of the specific heat capacity of local soil samples from the Niger delta, Nigeria with moisture content

International Nuclear Information System (INIS)

Ofoegbu, C.O.; Adjepong, S.K.

1987-11-01

Results of an investigation of the variation, with moisture content, of the specific heat capacity of samples of three texturally different types of soil (clayey, sandy and sandy loam) obtained from the Niger delta area of Nigeria, are presented. The results show that the specific heat capacities of the soils studied, increase with moisture content. This increase is found to be linear for the entire range of moisture contents considered (0-25%), in the case of the sandy loam soil while for the clayey and sandy soils the specific heat capacity is found to increase linearly with moisture content up to about 15% after which the increase becomes parabolic. The rate of increase of specific heat capacity with moisture content appears to be highest in the clayey soil and lowest in the sandy soil. It is thought that the differences in the rates of increase of specific heat capacity with moisture content, observed for the soils, reflect the soils' water-retention capacities. (author) 3 refs, 5 figs

Reusable Xerogel Containing Quantum Dots with High Fluorescence Retention

Directory of Open Access Journals (Sweden)

Xiang-Yong Liang

2018-03-01

Full Text Available Although various analytical methods have been established based on quantum dots (QDs, most were conducted in solution, which is inadequate for storage/transportation and rapid analysis. Moreover, the potential environmental problems caused by abandoned QDs cannot be ignored. In this paper, a reusable xerogel containing CdTe with strong emission is established by introducing host–guest interactions between QDs and polymer matrix. This xerogel shows high QDs loading capacity without decrease or redshift in fluorescence (the maximum of loading is 50 wt % of the final xerogel, which benefits from the steric hindrance of β-cyclodextrin (βCD molecules. Host–guest interactions immobilize QDs firmly, resulting in the excellent fluorescence retention of the xerogel. The good detecting performance and reusability mean this xerogel could be employed as a versatile analysis platform (for quantitative and qualitative analyses. In addition, the xerogel can be self-healed by the aid of water.

A Model for Freshman Engineering Retention

Science.gov (United States)

Veenstra, Cindy P.; Dey, Eric L.; Herrin, Gary D.

2009-01-01

With the current concern over the growing need for more engineers, there is an immediate need to improve freshman engineering retention. A working model for freshman engineering retention is needed. This paper proposes such a model based on Tinto's Interactionalist Theory. Emphasis in this model is placed on pre-college characteristics as…

Retention of Content Utilizing a Flipped Classroom Approach.

Science.gov (United States)

Shatto, Bobbi; LʼEcuyer, Kristine; Quinn, Jerod

The flipped classroom experience promotes retention and accountability for learning. The authors report their evaluation of a flipped classroom for accelerated second-degree nursing students during their primary medical-surgical nursing course. Standardized HESI® scores were compared between a group of students who experienced the flipped classroom and a previous group who had traditional teaching methods. Short- and long-term retention was measured using standardized exams 3 months and 12 months following the course. Results indicated that short-term retention was greater and long- term retention was significantly great in the students who were taught using flipped classroom methodology.

Approaches to developing the capacity of health policy analysis institutes: a comparative case study

Directory of Open Access Journals (Sweden)

Bennett Sara

2012-03-01

Full Text Available Abstract Objectives To review and assess (i the factors that facilitate the development of sustainable health policy analysis institutes in low and middle income countries and (ii the nature of external support for capacity development provided to such institutes. Methods Comparative case studies of six health policy analysis institutes (3 from Asia and 3 from Africa were conducted. In each region an NGO institute, an institute linked to government and a university based institute were included. Data collection comprised document review, semi-structured interviews with stakeholders and discussion of preliminary findings with institute staff. Findings The findings are organized around four key themes: (i Financial resources: three of the institutes had received substantial external grants at start-up, however two of these institutes subsequently collapsed. At all but one institute, reliance upon short term, donor funding, created high administrative costs and unpredictability. (ii Human resources: the retention of skilled human resources was perceived to be key to institute success but was problematic at all but one institute. In particular staff often moved to better paid positions elsewhere once having acquired necessary skills and experience, leaving remaining senior staff with heavy workloads. (iii Governance and management: board structures and roles varied according to the nature of institute ownership. Boards made important contributions to organizational capacity through promoting continuity, independence and fund raising. Routine management systems were typically perceived to be strong. (iv Networks: linkages to policy makers helped promote policy influences. External networks with other research organizations, particularly where these were longer term institutional collaborations helped promote capacity. Conclusions The development of strong in-country analytical and research capacity to guide health policy development is critical, yet

Optimising the weighting of the water retention index using sensitivity analysis

Science.gov (United States)

Becker, William; Vandecasteele, Ine

2015-04-01

A robust composite indicator was developed to assess the capacity of the landscape to regulate and retain water passing through it at Pan-European scale. The "Water Retention Index" (WRI) takes into account the role of interception by vegetation, the water-holding capacity of the soil, and the relative capacity of the bedrock to allow percolation of water, as well as the influence of soil sealing and slope gradient. A delicate issue in composite indicators is however the relative weighting of each variable used in the indicator - strong correlations and skewness are known to cause unequal influence of the input variables, even though the weighting coefficients are equal (Paruolo et al, 2013). To understand the effects of the weightings in the WRI, penalised splines were used to calculate the first order sensitivity index of each variable used in the construction of the WRI, allowing the true influence of each input to be determined. Furthermore, the weighting coefficients were optimised using an iterative nonlinear algorithm to find the coefficients which resulted in the most equal influence of each input to the indicator. In principle, this approach can be used to improve the weighting of many different kinds of composite indicator, the results of which are often used as the basis for important policy decisions at the European level. Paruolo, Paolo, Michaela Saisana, and Andrea Saltelli. "Ratings and rankings: voodoo or science?." Journal of the Royal Statistical Society: Series A (Statistics in Society) 176.3 (2013): 609-634.

Mucous retention cyst of the maxillary sinus.

Science.gov (United States)

Ruprecht, A; Batniji, S; el-Neweihi, E

1986-12-01

The mucous retention cyst is not a rare phenomenon. The incidence of dental patients was determined. Of 1685 patient radiographs reviewed, 44 (2.6%) had one or more mucous retention cysts in the maxillary sinuses.

Preparation and characterization of carbons for the retention of halogens in the condenser vacuum system of a thermonuclear plant

International Nuclear Information System (INIS)

Roman, S.; Gonzalez, J.F.; Ganan, J.; Sabio, E.; Gonzalez-Garcia, C.M.; Ramiro, A.; Mangut, V.

2006-01-01

Activated carbons were prepared by air and carbon dioxide activation, from almond tree pruning, with the aim of obtaining carbons that reproduce the textural and mechanical properties of the carbons currently used in the filtering system of the condenser vacuum installation of a Thermonuclear Plant (CNA; Central Nuclear de Almaraz in Caceres, Spain), produced from coconut shell. The variables studied in non-catalytic gasification series with air were the temperature (215-270 deg. C) and the time (1-16 h) and the influence of the addition of one catalyst (Co) and the time (1-2 h) in catalytic gasification. In the case of activation with CO 2 , the influence of the temperature (700-950 deg. C) and the time (1-8 h) was studied. The resulting carbons were characterized in terms of their BET surface, porosity, and pore size distribution. The N 2 adsorption isotherms at 77 K for both series showed a type I behaviour, typical of microporous materials. The isotherms showed that with both gasificant agents the temperature rise produced an increase in the carbon porosity. With regards to the activation time, a positive effect on the N 2 adsorbed volume on the carbons was observed. The best carbons of each series, as well as the CNA (carbon currently used in the CNA), were characterized by mercury porosimetry and iodine solution adsorption isotherms. The results obtained allowed to state that several of the carbons produced had characteristics similar to the carbon that is target of reproduction (which has S BET of 741 m 2 g -1 , V mi of 0.39 cm 3 g -1 and a iodine retention capacity of 429.3 mg g -1 ): carbon C (gasification with CO 2 at 850 deg. Cduring 1 h), with S BET of 523 m 2 g -1 , V mi of 0.33 cm 3 g -1 and a iodine retention capacity of 402.5 mg g -1 , and carbon D (gasification with CO 2 at 900 deg. Cduring 1 h), whose S BET is 672 m 2 g -1 , V mi is 0.28 cm 3 g -1 and has a iodine retention capacity of 345.2 mg g -1

[Study on retention and stability of linear occlusal complete dentures].

Science.gov (United States)

Zhang, Ping; Xu, Jun

2003-01-01

To learn retention and stability of linear occlusal complete dentures by investigating the subjective feelings of patient and the value of retention force. Static retention forces of maxillary and mandibular dentures were measured for 25 patients wearing linear occlusal dentures by using Hz-1 retention dynamometer. The subjective feelings of patients in functional state were gained simultaneously through questionnaire. Linear occlusal dentures demonstrate good retention in static and dynamic state. Among patients with severe resorption of residual ridge (RRR), mandibular linear occlusal dentures (shown good retentive subjective feelings) demonstrate significantly smaller retention force than those with slight or medium degree of RRR. There is no correlation between the subjective feelings and the values of retention forces of mandibular dentures. The subjective feelings of patients wearing new linear occlusal dentures are much better than that of old anatomic occlusal dentures. Linear occlusal dentures improve the performances of dentures by enhancing their stability during mastication movement.

Determination of quantitative retention-activity relationships between pharmacokinetic parameters and biological effectiveness fingerprints of Salvia miltiorrhiza constituents using biopartitioning and microemulsion high-performance liquid chromatography.

Science.gov (United States)

Gao, Haoshi; Huang, Hongzhang; Zheng, Aini; Yu, Nuojun; Li, Ning

2017-11-01

In this study, we analyzed danshen (Salvia miltiorrhiza) constituents using biopartitioning and microemulsion high-performance liquid chromatography (MELC). The quantitative retention-activity relationships (QRARs) of the constituents were established to model their pharmacokinetic (PK) parameters and chromatographic retention data, and generate their biological effectiveness fingerprints. A high-performance liquid chromatography (HPLC) method was established to determine the abundance of the extracted danshen constituents, such as sodium danshensu, rosmarinic acid, salvianolic acid B, protocatechuic aldehyde, cryptotanshinone, and tanshinone IIA. And another HPLC protocol was established to determine the abundance of those constituents in rat plasma samples. An experimental model was built in Sprague Dawley (SD) rats, and calculated the corresponding PK parameterst with 3P97 software package. Thirty-five model drugs were selected to test the PK parameter prediction capacities of the various MELC systems and to optimize the chromatographic protocols. QRARs and generated PK fingerprints were established. The test included water/oil-soluble danshen constituents and the prediction capacity of the regression model was validated. The results showed that the model had good predictability. Copyright © 2017. Published by Elsevier B.V.

Alveolar ridge rehabilitation to increase full denture retention and stability

Directory of Open Access Journals (Sweden)

Mefina Kuntjoro

2010-12-01

Full Text Available Background: Atrophic mandibular alveolar ridge generally complicates prostetic restoration expecially full denture. Low residual alveolar ridge and basal seat can cause unstable denture, permanent ulcer, pain, neuralgia, and mastication difficulty. Pre-proshetic surgery is needed to improve denture retention and stability. Augmentation is a major surgery to increase vertical height of the atrophic mandible while vestibuloplasty is aimed to increase the denture bearing area. Purpose: The augmentation and vestibuloplasty was aimed to provide stability and retentive denture atrophic mandibular alveolar ridge. Case: A 65 years old woman patient complained about uncomfortable denture. Clinical evaluate showed flat ridge in the anterior mandible, flabby tissue and candidiasis, while residual ridge height was classified into class IV. Case management: Augmentation using autograph was conducted as the mandible vertical height is less than 15 mm. Autograph was used to achieve better bone quantity and quality. Separated alveolar ridge was conducted from left to right canine region and was elevated 0.5 mm from the previous position to get new ridge in the anterior region. The separated alveolar ridge was fixated by using T-plate and ligature wire. Three months after augmentation fixation appliances was removed vestibuloplasty was performed to increase denture bearing area that can make a stable and retentive denture. Conclusion: Augmentation and vestibuloplasty can improve flat ridge to become prominent.Latar belakang: Ridge mandibula yang atrofi pada umumnya mempersulit pembuatan restorasi prostetik terutama gigi tiruan lengkap (GTL. Residual alveolar ridge dan basal seat yang rendah menyebabkan gigi tiruan menjadi tidak stabil, menimbulkan ulser permanen, nyeri, neuralgia, dan kesulitan mengunyah. Tujuan: Augmentasi dan vestibuloplasti pada ridge mandibula yang atrofi dilakukan untuk menciptakan gigi tiruan yang stabil dan retentive. Kasus: Pasien wanita

High cell density cultures produced by internal retention: application in continuous ethanol fermentation

Directory of Open Access Journals (Sweden)

Berta Carola Pérez

2004-07-01

Full Text Available Ethanol has provoked great interest due to its potential as an alternative fuel. Nevertheless, fermentation processes must be developed by increasing the low volumetric productivity achieved in conventional cultures (batch or continuous to make this product become economically competitive. This can be achieved by using techniques leading to high cell concentration and reducing inhibition by the end-product. One of the frequently employed methods involves cell recycling. This work thus developed a membrane reactor incorporating a filtration module with 5 u,m stainless steel tubular units inside a 3L stirred jar fermenter for investigating its application in continuous ethanol production. The effects of cell concentration and transmembrane pressure difference on permeate flux were evaluated for testing the filtration module's performance. The internal cell retention system was operated in Saccharomyces cerevisiae continuous culture derived from sucrose, once fermentation conditions had been selected (30 °C, 1.25 -1.75 vvm, pH 4.5. Filter unit permeability was maintained by applying pulses of air. More than 97% of the grown cells were retained in the fermenter, reaching 51 g/L cell concentration and 8.51 g/L.h average ethanol productivity in culture with internal cell retention; this was twice that obtained in a conventional continuous culture. Key words: Membrane reactor, Saccharomyces cerevisiae, alcoholic fermentation, cell recycling.

Effects of the radiation gamma on the activity and selectivity of the Al2 O3 in the retention of uranium and fission products

International Nuclear Information System (INIS)

Duran B, J.M.

1996-01-01

The study that here comes constitute a contribution for the treatment of based on waste the properties of retention of the inorganic oxides. The effect induced of the radiation has been determined gamma of the 60 Co in the Al 2 O 3 and their influence in their capacity of retention of uranium and products of fission of watery solutions strongly alkaline. In order to obtain useful information it made the superficial characterizations, structural, crystalline and of retention by means of the techniques of superficial adsorption, spectroscopy infrared, rays-X diffraction, liquid twinkling and γ- spectrometry. The obtained results show that the treatment of the Al 2 O 3 this associated with slight changes in their structural characteristics and superficialities concluding that the molecular water present in the crystalline net of the oxide was not displaced radiolytic for effect, but rather, this spread in the volume of the oxide, blocking the change in the contribution to crystalline of the oxide. (Author)

Absorptive capacity and smart companies

Directory of Open Access Journals (Sweden)

Patricia Moro González

2014-12-01

Full Text Available Purpose: The current competitive environment is substantially modifying the organizations’ learning processes due to a global increase of available information allowing this to be transformed into knowledge. This opportunity has been exploited since the nineties by the tools of “Business Analytics” and “Business Intelligence” but, nevertheless, being integrated in the study of new organizational capacities engaged in the process of creating intelligence inside organizations is still an outstanding task. The review of the concept of absorptive capacity and a detailed study from the perspective of this new reality will be the main objective of study of this paper.Design/methodology/approach: By comparing classical absorptive capacity and absorptive capacity from the point of view of information management tools in each one of the three stages of the organizational learning cycle, some gaps of the former are overcome/fulfilled. The academic/bibliographical references provided in this paper have been obtained from ISI web of knowledge, Scopus and Dialnet data bases, supporting the state of affairs on absorptive capacity and thereafter filtering by "Business Intelligence" and "Business Analytics". Specialized websites and Business Schools` Publications there have also been included, crowning the content on information management tools used that are currently used in the strategic consulting.Findings: Our contribution to the literature is the development of "smart absorptive capacity". This is a new capacity emerging from the reformulation of the classical concept of absorptive capacity wherein some aspects of its definition that might have been omitted are emphasized. The result of this new approach is the creation of a new Theoretical Model of Organizational Intelligence, which aims to explain, within the framework of the Resources and Capabilities Theory, the competitive advantage achieved by the so-called smart companies

The retention of first-generation college students in STEM: An extension of Tinto's longitudinal model

Science.gov (United States)

Uche, Ada Rosemary

In the current technologically advanced global economy, the role of human capital and education cannot be over-emphasized. Since almost all great inventions in the world have a scientific or technological foundation, having a skilled workforce is imperative for any nation's economic growth. Currently, large segments of the United States' population are underrepresented in the attainment of science, technology, engineering, and math (STEM) degrees, and in the STEM professions. Scholars, educators, policy-makers, and employers are concerned about the decline in student enrollment and graduation from STEM disciplines. This trend is especially problematic for first-generation college students. This study uses both quantitative and qualitative methods to assess the factors that predict the retention of first-generation college students in the STEM majors. It employs Tinto's longitudinal model (1993) as a conceptual framework to predict STEM retention for first-generation college students. The analysis uses the Beginning Post-secondary Students study (BPS 04/09) data and Roots of STEM qualitative data to investigate the role of first-generation status in STEM major retention. Results indicate that upper levels of achievement in high school math have a significant effect on first-generation status in STEM outcomes.

What factors determine academic achievement in high achieving undergraduate medical students? A qualitative study.

Science.gov (United States)

Abdulghani, Hamza M; Al-Drees, Abdulmajeed A; Khalil, Mahmood S; Ahmad, Farah; Ponnamperuma, Gominda G; Amin, Zubair

2014-04-01

Medical students' academic achievement is affected by many factors such as motivational beliefs and emotions. Although students with high intellectual capacity are selected to study medicine, their academic performance varies widely. The aim of this study is to explore the high achieving students' perceptions of factors contributing to academic achievement. Focus group discussions (FGD) were carried out with 10 male and 9 female high achieving (scores more than 85% in all tests) students, from the second, third, fourth and fifth academic years. During the FGDs, the students were encouraged to reflect on their learning strategies and activities. The discussion was audio-recorded, transcribed and analysed qualitatively. Factors influencing high academic achievement include: attendance to lectures, early revision, prioritization of learning needs, deep learning, learning in small groups, mind mapping, learning in skills lab, learning with patients, learning from mistakes, time management, and family support. Internal motivation and expected examination results are important drivers of high academic performance. Management of non-academic issues like sleep deprivation, homesickness, language barriers, and stress is also important for academic success. Addressing these factors, which might be unique for a given student community, in a systematic manner would be helpful to improve students' performance.

Super enhanced permeability and retention (SUPR) effects in tumors following near infrared photoimmunotherapy

Science.gov (United States)

Kobayashi, Hisataka; Choyke, Peter L.

2016-06-01

To date, the delivery of nano-sized therapeutic agents to cancers largely relies on enhanced permeability and retention (EPR) effects that are caused by the leaky nature of cancer vasculature. However, nano-sized agents delivered in this way have demonstrated limited success in oncology due to the relatively small magnitude of the EPR effect. For achieving superior delivery of nano-sized agents, super-enhanced permeability and retention (SUPR) effects are needed. Near infrared photo-immunotherapy (NIR-PIT) is a recently reported therapy that treats tumors with light therapy and subsequently causes an increase in nano-drug delivery up to 24-fold compared with untreated tumors in which only the EPR effect is present. SUPR effects could enhance delivery into tumor beds of a wide variety of nano-sized agents including particles, antibodies, and protein binding small molecular agents. Therefore, taking advantage of the SUPR effects after NIR-PIT may be a promising avenue to utilize a wide variety of nano-drugs in a highly effective manner.

Mode change design for capacity modulation in reciprocating compressor

International Nuclear Information System (INIS)

Bae, Young Ju; Kim, Jin Kook; Kim, Jong Bong; Chang, Young June

2008-01-01

Due to environmental issues, the development of low energy consumption products has become one of the main topics in the home appliance industry. The energy consumption of a refrigerator depends on the efficiency of its compressor as well as on the refrigerator cycle design, such as the capacity modulation. This study features the design of a novel capacity modulation reciprocating compressor, i.e., two-step capacity modulation (TCM). In a TCM compressor, capacity modulation is achieved by changing the dead volume in the cylinder. Instead of a concentric sleeve, an eccentric sleeve is used to change the dead volume for the clockwise and counterclockwise rotation of a motor. For stable capacity modulation, a new latching system with a key, a spring, and an eccentric sleeve is introduced, and the mode change reliability is verified by dynamic analysis

Global Disease Detection-Achievements in Applied Public Health Research, Capacity Building, and Public Health Diplomacy, 2001-2016.

Science.gov (United States)

Rao, Carol Y; Goryoka, Grace W; Henao, Olga L; Clarke, Kevin R; Salyer, Stephanie J; Montgomery, Joel M

2017-11-01

The Centers for Disease Control and Prevention has established 10 Global Disease Detection (GDD) Program regional centers around the world that serve as centers of excellence for public health research on emerging and reemerging infectious diseases. The core activities of the GDD Program focus on applied public health research, surveillance, laboratory, public health informatics, and technical capacity building. During 2015-2016, program staff conducted 205 discrete projects on a range of topics, including acute respiratory illnesses, health systems strengthening, infectious diseases at the human-animal interface, and emerging infectious diseases. Projects incorporated multiple core activities, with technical capacity building being most prevalent. Collaborating with host countries to implement such projects promotes public health diplomacy. The GDD Program continues to work with countries to strengthen core capacities so that emerging diseases can be detected and stopped faster and closer to the source, thereby enhancing global health security.

Investigation of Phosphate Retention in some Allophanic and Non-Allophanic Nano-Clays from Karaj Formation

Directory of Open Access Journals (Sweden)

Mohammad Ali Monajjem

2017-02-01

Full Text Available Introduction: Nanoclays, due to their high specific surface area (SSA chemical and mechanical stabilities, and a variety of surface and structural properties are widely applied. Some of their applications are using them as nano composite polymers, heavy metal ions absorbents, catalysts, photochemical reaction fields, ceramics, paper fillings and coatings, sensors and biosensors. Nano clays and Clays are the most important components constructing soil ecosystems. The physical and chemical properties of soils are mainly depending on the type and amount their clay fraction pertaining to considerable nanoclays. Nano clays have been frequently used to eliminate environmental contaminants from soil and water. Nano clays have also an effective role in the phosphate sorption and desorption from soil solution. Phosphate retention is highly affected by the chemical bonds of the materials, cristalographic properties and pH. In clay size particles there are different structures of nano particles such as alominosilicates with nano ball and nano tube construction. Soils with andic properties have amorphous clay minerals such as allophone. Allophane has a diameter of 3 to 5 nano meter under a transmission electron microscope (TEM and its atomic Si/Al ratio ranges between 0.5 and 1. Allophane shows variable charge characteristics and high selectivity for divalent cations, and is highly reactive with phosphate. Materials and Methods: The objective of this research was to inspect the effect of soil components particularly clay and nanoclay on the sorption of phosphate. To achieve this goal, we studied the amount of phosphate sorption by the natural nanoclays. Samples with andic and vitric properties which were previously formed on volcanic ash in Karaj were chosen in 5 pedons as two Andic ( > 5 percent volcanic glass, > 25 percent P retention, pH NaF > 8.6 and Alo +½ Feo > 0.4 and non Andic soils.. After removal of organic materials, soluble salts, carbonates

Building Capacity for Protected Area Management in Lao PDR

Science.gov (United States)

Rao, Madhu; Johnson, Arlyne; Spence, Kelly; Sypasong, Ahnsany; Bynum, Nora; Sterling, Eleanor; Phimminith, Thavy; Praxaysombath, Bounthob

2014-04-01

Declining biodiversity in protected areas in Laos is attributed to unsustainable exploitation of natural resources. At a basic level, an important need is to develop capacity in academic and professional training institutions to provide relevant training to conservation professionals. The paper (a) describes the capacity building approach undertaken to achieve this goal, (b) evaluates the effectiveness of the approach in building capacity for implementing conservation and (c) reviews implementation outcomes. Strong linkages between organizations implementing field conservation, professional training institutions, and relevant Government agencies are central to enhancing effectiveness of capacity building initiatives aimed at improving the practice of conservation. Protected area management technical capacity needs will need to directly influence curriculum design to insure both relevance and effectiveness of training in improving protected area management. Sustainability of capacity building initiatives is largely dependent on the level of interest and commitment by host-country institutions within a supportive Government policy framework in addition to engagement of organizations implementing conservation.

Radionuclide Retention Mechanisms in Secondary Waste-Form Testing: Phase II

Energy Technology Data Exchange (ETDEWEB)

Um, Wooyong; Valenta, Michelle M.; Chung, Chul-Woo; Yang, Jungseok; Engelhard, Mark H.; Serne, R. Jeffrey; Parker, Kent E.; Wang, Guohui; Cantrell, Kirk J.; Westsik, Joseph H.

2011-09-26

This report describes the results from laboratory tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate candidate stabilization technologies that have the potential to successfully treat liquid secondary waste stream effluents produced by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). WRPS is considering the design and construction of a Solidification Treatment Unit (STU) for the Effluent Treatment Facility (ETF) at Hanford. The ETF, a multi-waste, treatment-and-storage unit that has been permitted under the Resource Conservation and Recovery Act (RCRA), can accept dangerous, low-level, and mixed wastewaters for treatment. The STU needs to be operational by 2018 to receive secondary liquid waste generated during operation of the WTP. The STU will provide the additional capacity needed for ETF to process the increased volume of secondary waste expected to be produced by WTP. This report on radionuclide retention mechanisms describes the testing and characterization results that improve understanding of radionuclide retention mechanisms, especially for pertechnetate, {sup 99}TcO{sub 4}{sup -} in four different waste forms: Cast Stone, DuraLith alkali aluminosilicate geopolymer, encapsulated fluidized bed steam reforming (FBSR) product, and Ceramicrete phosphate bonded ceramic. These data and results will be used to fill existing data gaps on the candidate technologies to support a decision-making process that will identify a subset of the candidate waste forms that are most promising and should undergo further performance testing.

Reduced short-term memory capacity in Alzheimer's disease: the role of phonological, lexical, and semantic processing.

Science.gov (United States)

Caza, Nicole; Belleville, Sylvie

2008-05-01

Individuals with Alzheimer's disease (AD) are often reported to have reduced verbal short-term memory capacity, typically attributed to their attention/executive deficits. However, these individuals also tend to show progressive impairment of semantic, lexical, and phonological processing which may underlie their low short-term memory capacity. The goals of this study were to assess the contribution of each level of representation (phonological, lexical, and semantic) to immediate serial recall performance in 18 individuals with AD, and to examine how these linguistic effects on short-term memory were modulated by their reduced capacity to manipulate information in short-term memory associated with executive dysfunction. Results showed that individuals with AD had difficulty recalling items that relied on phonological representations, which led to increased lexicality effects relative to the control group. This finding suggests that patients have a greater reliance on lexical/semantic information than controls, possibly to make up for deficits in retention and processing of phonological material. This lexical/semantic effect was not found to be significantly correlated with patients' capacity to manipulate verbal material in short-term memory, indicating that language processing and executive deficits may independently contribute to reducing verbal short-term memory capacity in AD.

Continuing dental education in radiation protection: knowledge retention following a postgraduate course.

Science.gov (United States)

Absi, E G; Drage, N A; Thomas, H S; Newcombe, R G; Cowpe, J

2011-08-01

To evaluate medium-term knowledge retention of dental personnel following attendance at a postgraduate course in radiation protection. Knowledge was measured using identical pre- and post-course validated single best-answer multiple-choice instruments, administered immediately before and after training and at follow-up at 6 or 12 months. These comprise 16 questions each with 5 choices. The range of possible scores was from 0 to 16, and scores were scaled to percentages. Participants were predominantly dental practitioners, but a minority consisted of dental care professionals (dental nurses, hygienists and therapists). Of 285 participants, 272 (95.4%) completed both pre- and post-course questionnaires. One hundred and seventeen (43%) of these also completed the follow-up test, but only 109 (40%) individuals could be linked to the original course. Mean (standard deviation) pre-, post-course and follow-up-corrected percentage scores were 39.1 (16.1), 74.6 (16.9) and 58.9 (22.7), respectively. There was attrition in knowledge at follow-up: the average increase in adjusted score after training was 35.5 points, but only 56% of this was retained at follow-up. Paired t-tests confirmed that the mean score at follow-up was firmly intermediate between the pre- and post-course scores. Of the 109 participants, 7 (6%) achieved a satisfactory score pre-training, 82 (75%) immediately post-training and 41 (38%) at follow-up. There were gross differences between the levels of performance achieved for the eight subject areas tested. Immediate post-course assessments have indicated that current postgraduate courses in radiation protection are effective. However, a substantial amount of knowledge is lost by 6-12 months following course attendance. To achieve long-term knowledge retention, early or repeated reinforcement may be necessary. © 2011 John Wiley & Sons A/S.

Wind Effects on Retention Time in Highway Ponds

DEFF Research Database (Denmark)

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

2007-01-01

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

Wind Effects on Retention Time in Highway Ponds

DEFF Research Database (Denmark)

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

2008-01-01

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

The influence of Lampblack on capacity retention in Pb/PbSO/sub 4/ electrodes with forced flow of electrolyte

Energy Technology Data Exchange (ETDEWEB)

Borger, W.; Hullmeine, U.

1984-10-01

High active material utilization of Pb/PbSO/sub 4/ electrodes after formation in the range of 170 - 120 Ah/kg is obtained when these electrodes are discharged at 50-200 A/kg current density with forced flow of electrolyte. Decline of capacity was observed on further cycling at high current density and forced flow of electrolyte. The extent of capacity decline in these electrodes is largely influenced by the amount of additives in the active material, e.g. lampblack and expander.

Retention and failure morphology of prefabricated posts

DEFF Research Database (Denmark)

Sahafi, Alireza; Peutzfeldt, Anne; Asmussen, Erik

2004-01-01

PURPOSE: This study evaluated the effect of cement, post material, surface treatment, and shape (1) on the retention of posts luted in the root canals of extracted human teeth and (2) on the failure morphology. MATERIALS AND METHODS: Posts of titanium alloy (ParaPost XH), glass fiber (Para...... at 37 degrees C for 7 days, retention was determined by extraction of the posts. Failure morphology of extracted posts was analyzed and quantified stereomicroscopically. RESULTS: Type of luting cement, post material, and shape of post influenced the retention and failure morphology of the posts. Because...

Urinary retention associated with herpes zoster infection.

Science.gov (United States)

Cohen, L M; Fowler, J F; Owen, L G; Callen, J P

1993-01-01

Herpes zoster infection particularly involving the sacral dermatomes has been associated with bladder and bowel dysfunction, most commonly urinary retention. We report two patients who developed acute urinary retention, one of whom also had constipation, within days of herpes zoster skin lesions of the S2-S4 dermatomes. Herpes zoster is a reversible cause of neurogenic bladder and bowel dysfunction and should be considered in a patient that presents with acute urinary retention and/or constipation. Sensory abnormalities and flaccid detrusor paralysis are most likely involved in the pathogenesis.

Drug Retention Times

Energy Technology Data Exchange (ETDEWEB)

Center for Human Reliability Studies

2007-05-01

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

The sensory strength of voluntary visual imagery predicts visual working memory capacity.

Science.gov (United States)

Keogh, Rebecca; Pearson, Joel

2014-10-09

How much we can actively hold in mind is severely limited and differs greatly from one person to the next. Why some individuals have greater capacities than others is largely unknown. Here, we investigated why such large variations in visual working memory (VWM) capacity might occur, by examining the relationship between visual working memory and visual mental imagery. To assess visual working memory capacity participants were required to remember the orientation of a number of Gabor patches and make subsequent judgments about relative changes in orientation. The sensory strength of voluntary imagery was measured using a previously documented binocular rivalry paradigm. Participants with greater imagery strength also had greater visual working memory capacity. However, they were no better on a verbal number working memory task. Introducing a uniform luminous background during the retention interval of the visual working memory task reduced memory capacity, but only for those with strong imagery. Likewise, for the good imagers increasing background luminance during imagery generation reduced its effect on subsequent binocular rivalry. Luminance increases did not affect any of the subgroups on the verbal number working memory task. Together, these results suggest that luminance was disrupting sensory mechanisms common to both visual working memory and imagery, and not a general working memory system. The disruptive selectivity of background luminance suggests that good imagers, unlike moderate or poor imagers, may use imagery as a mnemonic strategy to perform the visual working memory task. © 2014 ARVO.

Promoting Special Educator Teacher Retention

Directory of Open Access Journals (Sweden)

Jeremy E. Vittek

2015-06-01

Full Text Available This article is a critical review of the literature on special education teacher attrition and retention. The research focused on journal articles from 2004 to present. The results of the study helped define special educator attrition and retention. The major themes present in the findings were job satisfaction, administrative support, induction programs, and mentoring. The literature shows a clear need for comprehensive administrative support to improve job satisfaction and the likelihood a special educator will remain in their job.

Radionuclide migration in geological formations

International Nuclear Information System (INIS)

Barbreau, A.; Heremans, R.; Skytte Jensen, B.

1980-01-01

Radioactive waste disposal into geological formation is based on the capacity of rocks to confine radioactivity for a long period of time. Radionuclide migration from the repository to the environment depends on different mechanisms and phenomena whose two main ones are groundwater flow and the retention and ion-exchange property of rocks. Many studies are underway presently in EEC countries concerning hydrodynamic characteristics of deep geological formations as well as in radionuclide retention capacity and modelling. Important results have already been achieved which show the complexity of some phenomena and further studies shall principally be developed taking into account real conditions of the repository and its environment

Retention in a public health care system with free access to treatment

DEFF Research Database (Denmark)

Helleberg, Marie; Engsig, Frederik N; Kronborg, Gitte

2012-01-01

were retained in care 95.0% of person-years under observation, increasing to 98.1% after initiation of antiretroviral treatment (HAART). The overall IR/100 person-years for first episode of LTFU was 2.6 (95% CI: 2.5-2.8) and was significantly lower after initiation of HAART (1.2 (95% CI: 1......, especially after initiation of HAART. Absence from HIV care is associated with increased mortality. We conclude that high rates of retention can be achieved in a health care system with free access to treatment and is associated with a favorable outcome....

Retention performance of green roofs in three different climate regions

Science.gov (United States)

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

2016-11-01

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

Robustness indicators and capacity models for railway networks

DEFF Research Database (Denmark)

Jensen, Lars Wittrup

In a world continuous striving for higher mobility and the use of more sustainable modes of transport, there is a constant pressure on utilising railway capacity better and, at the same time, obtaining a high robustness against delays. During the planning of railway operations and infrastructure ....... This has motivated the research conducted and described in this thesis, where the objective has been to develop and improve existing methods to achieve timetable and infrastructure plans with robust capacity utilisation aimed at the strategic and early tactical planning phases....

Herpes zoster-induced acute urinary retention.

Science.gov (United States)

Addison, Ben; Harvey, Martyn

2013-06-01

Urinary retention is a common acute presentation for men in their later decades. Potential contributing pathologies are numerous. We report an unusual case of acute urinary retention requiring catheterisation secondary to sacral herpes zoster reactivation (S2-4) in an 88-year-old man with minimal preceding obstructive symptoms. © 2013 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Job satisfaction and retention of midwives in rural Nigeria.

Science.gov (United States)

Adegoke, A A; Atiyaye, F B; Abubakar, A S; Auta, A; Aboda, A

2015-10-01

scheme within two years, of which 16 (18%) wanted to leave within one year. However, 39% of the midwives (n=34) indicated that they would be happy to continue working even after the scheme has ended. Of these 34 participants, 18 would like to continue working in the same facility where they are now whereas the remaining 16 would like to continue working in the north but not in the facility where they are working currently. Eight themes on job satisfaction and retention emerged from the FGDs conducted with current midwives, whereas six themes emerged from the exit interviews from midwives who have left the scheme. the MSS programme is a short-term solution to increase SBA coverage in rural Nigeria. MSS midwives were dissatisfied with the short term contract, lack of career structure, irregular payment, poor working condition, inadequate supervision and poor accommodation being offered by the programme, which all contribute to poor retention of MSS midwives. IMPLICATIONS FOR POLICY AND PRACTICE: midwives׳ job satisfaction and retention are critical to improving the health of mothers and their newborn. Poor job satisfaction and retention therefore requires improvements in financial and non-financial incentives, health systems, supportive supervision, ensuring job security and a career structure for midwives working in rural health facilities. Initiating effective strategies to motivate and increase the retention of rural health workers is important for Nigeria to achieve the Millennium/Sustainable Development Goals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of biochar amendment on soil's retention capacity for estrogenic hormones from poultry manure treatment

Institute of Scientific and Technical Information of China (English)

Sukhjot MANN; Zhiming QI; Shiv O.PRASHER; Lanhai LI; Dongwei GUI; Qianjing JIANG

2017-01-01

Most animals,including humans,produce natural sex hormones such as estrogens:17β-estradiol (E2) and estrone (El).These compounds are able to disrupt the reproductive systems of living organisms at trace concentrations (ng.L-1).This experiment tests the hypothesis that 1％ slow pyrolysis biochar-amended sandy soil could retain significant amount of estrogens (El,E2) from poultry manure in its second year of application.The experiment was conducted over 46 days and consisted of a series of lysimeters containing sandy soil with biocharamended topsoil.The application rate of poultry manure was kept at 2.47 kg.m-2.The biochar held a significant concentration of hormone during the first year of its application.However,in the following year (current study),there was no significant retention of hormones in the biochar-amended soil.During the first year after application,the biochar was fresh,so its pores were available for hydrophobic interactions and held significant concentration of hormones.As time passed there were several biotic and abiotic changes on the surface of the biochar so that after some physical fragmentation,pores on the surface were no longer available for hydrophobic interactions.The biochar started releasing dissolved organic carbon,which facilitated greater mobility of hormones from poultry manure down the soil profile.

Scale-up, retention and HIV/STI prevalence trends among female sex workers attending VICITS clinics in Guatemala.

Directory of Open Access Journals (Sweden)

Sonia Morales-Miranda

Full Text Available Since 2007, Guatemala integrated STI clinical service with an HIV prevention model into four existing public health clinics to prevent HIV infection, known as the VICITS strategy. We present the first assessment of VICITS scale-up, retention, HIV and STI prevalence trends, and risk factors associated with HIV infection among Female Sex Workers (FSW attending VICITS clinics in Guatemala.Demographic, behavioral and clinical data were collected using a standardized form. Data was analyzed by year and health center. HIV and STI prevalence were estimated from routine visits. Retention was estimated as the percent of new users attending VICITS clinics who returned for at least one follow-up visit to any VICITS clinic within 12 months. Separate multivariate logistic regression models were conducted to investigate factors associated with HIV infection and program retention.During 2007-2011 5,682 FSW visited a VICITS clinic for the first-time. HIV prevalence varied from 0.4% to 5.8%, and chlamydia prevalence from 0% to 14.3%, across sites. Attending the Puerto Barrios clinic, having a current syphilis infection, working primarily on the street, and using the telephone or internet to contact clients were associated with HIV infection. The number of FSW accessing VICITS annually increased from 556 to 2,557 (361% during the period. In 2011 retention varied across locations from 7.7% to 42.7%. Factors negatively impacting retention included current HIV diagnosis, having practiced sex work in another country, being born in Honduras, and attending Marco Antonio Foundation or Quetzaltenango clinic sites. Systematic time trends did not emerge, however 2008 and 2010 were characterized by reduced retention.Our data show local differences in HIV prevalence and clinic attendance that can be used to prioritize prevention activities targeting FSW in Guatemala. VICITS achieved rapid scale-up; however, a better understanding of the causes of low return rates is urgently

Scale-up, retention and HIV/STI prevalence trends among female sex workers attending VICITS clinics in Guatemala.

Science.gov (United States)

Morales-Miranda, Sonia; Jacobson, Jerry O; Loya-Montiel, Itzel; Mendizabal-Burastero, Ricardo; Galindo-Arandi, César; Flores, Carlos; Chen, Sanny Y

2014-01-01

Since 2007, Guatemala integrated STI clinical service with an HIV prevention model into four existing public health clinics to prevent HIV infection, known as the VICITS strategy. We present the first assessment of VICITS scale-up, retention, HIV and STI prevalence trends, and risk factors associated with HIV infection among Female Sex Workers (FSW) attending VICITS clinics in Guatemala. Demographic, behavioral and clinical data were collected using a standardized form. Data was analyzed by year and health center. HIV and STI prevalence were estimated from routine visits. Retention was estimated as the percent of new users attending VICITS clinics who returned for at least one follow-up visit to any VICITS clinic within 12 months. Separate multivariate logistic regression models were conducted to investigate factors associated with HIV infection and program retention. During 2007-2011 5,682 FSW visited a VICITS clinic for the first-time. HIV prevalence varied from 0.4% to 5.8%, and chlamydia prevalence from 0% to 14.3%, across sites. Attending the Puerto Barrios clinic, having a current syphilis infection, working primarily on the street, and using the telephone or internet to contact clients were associated with HIV infection. The number of FSW accessing VICITS annually increased from 556 to 2,557 (361%) during the period. In 2011 retention varied across locations from 7.7% to 42.7%. Factors negatively impacting retention included current HIV diagnosis, having practiced sex work in another country, being born in Honduras, and attending Marco Antonio Foundation or Quetzaltenango clinic sites. Systematic time trends did not emerge, however 2008 and 2010 were characterized by reduced retention. Our data show local differences in HIV prevalence and clinic attendance that can be used to prioritize prevention activities targeting FSW in Guatemala. VICITS achieved rapid scale-up; however, a better understanding of the causes of low return rates is urgently needed.

Effective capacity of multiple antenna channels: Correlation and keyhole

KAUST Repository

Zhong, Caijun

2012-01-01

In this study, the authors derive the effective capacity limits for multiple antenna channels which quantify the maximum achievable rate with consideration of link-layer delay-bound violation probability. Both correlated multiple-input single-output and multiple-input multiple-output keyhole channels are studied. Based on the closed-form exact expressions for the effective capacity of both channels, the authors look into the asymptotic high and low signal-to-noise ratio regimes, and derive simple expressions to gain more insights. The impact of spatial correlation on effective capacity is also characterised with the aid of a majorisation theory result. It is revealed that antenna correlation reduces the effective capacity of the channels and a stringent quality-of-service requirement causes a severe reduction in the effective capacity but can be alleviated by increasing the number of antennas. © 2012 The Institution of Engineering and Technology.

Effective capacity of multiple antenna channels: Correlation and keyhole

KAUST Repository

Zhong, Caijun; Ratnarajah, Tharm; Wong, Kaikit; Alouini, Mohamed-Slim

2012-01-01

In this study, the authors derive the effective capacity limits for multiple antenna channels which quantify the maximum achievable rate with consideration of link-layer delay-bound violation probability. Both correlated multiple-input single

Assessment of pedotransfer functions for estimating soil water retention curves for the amazon region

Directory of Open Access Journals (Sweden)

João Carlos Medeiros

2014-06-01

Full Text Available Knowledge of the soil water retention curve (SWRC is essential for understanding and modeling hydraulic processes in the soil. However, direct determination of the SWRC is time consuming and costly. In addition, it requires a large number of samples, due to the high spatial and temporal variability of soil hydraulic properties. An alternative is the use of models, called pedotransfer functions (PTFs, which estimate the SWRC from easy-to-measure properties. The aim of this paper was to test the accuracy of 16 point or parametric PTFs reported in the literature on different soils from the south and southeast of the State of Pará, Brazil. The PTFs tested were proposed by Pidgeon (1972, Lal (1979, Aina & Periaswamy (1985, Arruda et al. (1987, Dijkerman (1988, Vereecken et al. (1989, Batjes (1996, van den Berg et al. (1997, Tomasella et al. (2000, Hodnett & Tomasella (2002, Oliveira et al. (2002, and Barros (2010. We used a database that includes soil texture (sand, silt, and clay, bulk density, soil organic carbon, soil pH, cation exchange capacity, and the SWRC. Most of the PTFs tested did not show good performance in estimating the SWRC. The parametric PTFs, however, performed better than the point PTFs in assessing the SWRC in the tested region. Among the parametric PTFs, those proposed by Tomasella et al. (2000 achieved the best accuracy in estimating the empirical parameters of the van Genuchten (1980 model, especially when tested in the top soil layer.

Emergent biosynthetic capacity in simple microbial communities.

Directory of Open Access Journals (Sweden)

Hsuan-Chao Chiu

2014-07-01

Full Text Available Microbes have an astonishing capacity to transform their environments. Yet, the metabolic capacity of a single species is limited and the vast majority of microorganisms form complex communities and join forces to exhibit capabilities far exceeding those achieved by any single species. Such enhanced metabolic capacities represent a promising route to many medical, environmental, and industrial applications and call for the development of a predictive, systems-level understanding of synergistic microbial capacity. Here we present a comprehensive computational framework, integrating high-quality metabolic models of multiple species, temporal dynamics, and flux variability analysis, to study the metabolic capacity and dynamics of simple two-species microbial ecosystems. We specifically focus on detecting emergent biosynthetic capacity--instances in which a community growing on some medium produces and secretes metabolites that are not secreted by any member species when growing in isolation on that same medium. Using this framework to model a large collection of two-species communities on multiple media, we demonstrate that emergent biosynthetic capacity is highly prevalent. We identify commonly observed emergent metabolites and metabolic reprogramming patterns, characterizing typical mechanisms of emergent capacity. We further find that emergent secretion tends to occur in two waves, the first as soon as the two organisms are introduced, and the second when the medium is depleted and nutrients become limited. Finally, aiming to identify global community determinants of emergent capacity, we find a marked association between the level of emergent biosynthetic capacity and the functional/phylogenetic distance between community members. Specifically, we demonstrate a "Goldilocks" principle, where high levels of emergent capacity are observed when the species comprising the community are functionally neither too close, nor too distant. Taken together

The Effects of Long-Duration Spaceflight on Training Retention and Transfer

Science.gov (United States)

Barshi, Immanuel; Healy, Alice; Dempsey, Donna L.; McGuire, Kerry M.; Landon, Lauren B.

2018-01-01

Training our crew members for long duration, exploration-class missions will have to maximize long-term retention and transfer of the trained skills. The expected duration of the missions, our inability to predict all the possible tasks the crew will be called upon to perform, and the low training-to-mission time ratio require that the training be maximally effective such that the skills acquired during training will be retained and will be transferrable across a wide range of specific tasks that are different from the particular tasks used during training. However, to be able to design training that can achieve these ambitious goals, we must first understand the ways in which long-duration spaceflight affects training retention and transfer. Current theories of training retention and transfer are largely based on experimental studies conducted at university laboratories using undergraduate students as participants. Furthermore, all such studies have been conducted on Earth. We do not know how well the results of these studies predict the performance of crew members. More specifically, we do not know how well the results of these studies predict the performance of crew members in space and especially during long-duration missions. To address this gap in our knowledge, the current on-going study seeks to test the null hypothesis that performance of university undergraduate students on Earth on training retention and transfer tests do in fact predict accurately the performance of crew members during long-duration spaceflights. To test this hypothesis, the study employs a single 16-month long experimental protocol with 3 different participant groups: undergraduate university students, crew members on the ground, and crew members in space. Results from this study will be presented upon its completion. This poster presents results of study trials of the two tasks used in this study: a data entry task and a mapping task. By researching established training principles, by

Low-SNR Capacity of MIMO Optical Intensity Channels

KAUST Repository

Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

2017-01-01

The capacity of the multiple-input multiple-output (MIMO) optical intensity channel is studied, under both average and peak intensity constraints. We focus on low SNR, which can be modeled as the scenario where both constraints proportionally vanish, or where the peak constraint is held constant while the average constraint vanishes. A capacity upper bound is derived, and is shown to be tight at low SNR under both scenarios. The capacity achieving input distribution at low SNR is shown to be a maximally-correlated vector-binary input distribution. Consequently, the low-SNR capacity of the channel is characterized. As a byproduct, it is shown that for a channel with peak intensity constraints only, or with peak intensity constraints and individual (per aperture) average intensity constraints, a simple scheme composed of coded on-off keying, spatial repetition, and maximum-ratio combining is optimal at low SNR.

Low-SNR Capacity of MIMO Optical Intensity Channels

KAUST Repository

Chaaban, Anas

2017-09-18

The capacity of the multiple-input multiple-output (MIMO) optical intensity channel is studied, under both average and peak intensity constraints. We focus on low SNR, which can be modeled as the scenario where both constraints proportionally vanish, or where the peak constraint is held constant while the average constraint vanishes. A capacity upper bound is derived, and is shown to be tight at low SNR under both scenarios. The capacity achieving input distribution at low SNR is shown to be a maximally-correlated vector-binary input distribution. Consequently, the low-SNR capacity of the channel is characterized. As a byproduct, it is shown that for a channel with peak intensity constraints only, or with peak intensity constraints and individual (per aperture) average intensity constraints, a simple scheme composed of coded on-off keying, spatial repetition, and maximum-ratio combining is optimal at low SNR.

Collaborative-group testing improves learning and knowledge retention of human physiology topics in second-year medical students.

Science.gov (United States)

Vázquez-García, Mario

2018-06-01

The present study examined the relationship between second-year medical students' group performance and individual performance in a collaborative-learning environment. In recent decades, university professors in the scientific and humanistic disciplines have successfully put into practice different modalities of collaborative approaches to teaching. Essentially, collaborative approach refers to a variety of techniques that involves the joint intellectual effort of a small group of students, which encourages interaction and discussion among students and professors. The present results show the efficacy of collaborative learning, which, furthermore, allowed students to participate actively in the physiology class. Average student's grades were significantly higher when they engaged in single-best-response, multiple-choice tests as a student team, compared with taking the same examinations individually. The method improved notably knowledge retention, as learning is more effective when performed in the context of collaborative partnership. A selected subset of questions answered wrongly in an initial test, both individually and collectively, was used on a second test to examine student retention of studied material. Grade averages were significantly improved, both individually and groupwise, when students responded to the subset of questions a second time, 1, 2, or 3 wk after the first attempt. These results suggest that the collaborative approach to teaching allowed a more effective understanding of course content, which meant an improved capacity for retention of human physiology knowledge.

Nuclear reactor melt-retention structure to mitigate direct containment heating

Science.gov (United States)

Tutu, Narinder K.; Ginsberg, Theodore; Klages, John R.

1991-01-01

A light water nuclear reactor melt-retention structure to mitigate the extent of direct containment heating of the reactor containment building. The structure includes a retention chamber for retaining molten core material away from the upper regions of the reactor containment building when a severe accident causes the bottom of the pressure vessel of the reactor to fail and discharge such molten material under high pressure through the reactor cavity into the retention chamber. In combination with the melt-retention chamber there is provided a passageway that includes molten core droplet deflector vanes and has gas vent means in its upper surface, which means are operable to deflect molten core droplets into the retention chamber while allowing high pressure steam and gases to be vented into the upper regions of the containment building. A plurality of platforms are mounted within the passageway and the melt-retention structure to direct the flow of molten core material and help retain it within the melt-retention chamber. In addition, ribs are mounted at spaced positions on the floor of the melt-retention chamber, and grid means are positioned at the entrance side of the retention chamber. The grid means develop gas back pressure that helps separate the molten core droplets from discharged high pressure steam and gases, thereby forcing the steam and gases to vent into the upper regions of the reactor containment building.

Research Regarding Membrane Filtration Capacity of Water Collected from Siret River

Science.gov (United States)

Mihalache, I.; Pintilie, Ş. C.; Bîrsan, I. G.; Dănăila, E.; Baltă, Ş.

2018-06-01

In the past decade, the high demand and strict legislations regarding pure and potable water production and quality require finding new treatment technologies with higher effectiveness. When compared with conventional treatment technologies, membrane technology is a viable option in water and wastewater treatment due to high performance, ease in implementation, cost-efficiency among other advantages, also, leading to a rapid expansion in use in almost all areas of industry. Polymeric ultrafiltration membranes have been successfully used in various industries since 1969, and in later years they were studied in the water purification sector, mainly as a pre-treatment step to reduce severe fouling that could occur in reverse osmosis filtration stage. Polysulfone (PSf) was the polymer of choice in this study with two concentrations, 25 wt.% and 30 wt.%. Surface SEM morphology, roughness and water affinity were analyzed for the studied membranes. Water from Siret river was used in the permeation tests in order to analyze the retention capacity and anti-fouling ability. The present study revealed higher retention for the 30 wt.% PSf membranes, from the physico-chemical and microbiological point-of-view and lower fouling, also.

The Causal Effects of Grade Retention on Behavioral Outcomes

Science.gov (United States)

Martorell, Paco; Mariano, Louis T.

2018-01-01

This study examines the impact of grade retention on behavioral outcomes under a comprehensive assessment-based student promotion policy in New York City. To isolate the causal effect of grade retention, we implement a fuzzy regression discontinuity (RD) design that exploits the fact that grade retention is largely determined by whether a student…

Comparison of pharmaceutical nanoformulations for curcumin: Enhancement of aqueous solubility and carrier retention.

Science.gov (United States)

Allijn, Iris E; Schiffelers, Raymond M; Storm, Gert

2016-06-15

Curcumin, originally used in traditional medicine and as a spice, is one of the most studied and most popular natural products of the past decade. It has been described to be an effective anti-inflammatory and anti-cancer drug and protects against chronic diseases such as rheumatoid arthritis and atherosclerosis. Despite these promising pharmacological properties, curcumin is also very lipophilic, which makes its formulation challenging. Ideally the nanocarrier should additionally also retain the encapsulated curcumin to provide target tissue accumulation. In this study we aimed to tackle this aqueous solubility and carrier retention challenge of curcumin by encapsulating curcumin in different nanoparticles. We successfully loaded LDL (30nm), polymeric micelles (80nm), liposomes (180nm) and Intralipid (280nm) with curcumin. The relative loading capacity was inversely related to the size of the particle. The stability for all formulations was determined in fetal bovine serum over a course of 24h. Although all curcumin-nanoparticles were stable in buffer solution, all leaked more than 70% of curcumin under physiological conditions. Altogether, tested nanoparticles do solve the aqueous insolubility problem of curcumin, however, because of their leaky nature, the challenge of carrier retention remains. Copyright © 2016 Elsevier B.V. All rights reserved.

Transmutation effects on long-term Cs retention in phyllosilicate minerals from first principles.

Science.gov (United States)

Sassi, Michel; Okumura, Masahiko; Machida, Masahiko; Rosso, Kevin M

2017-10-11

The accidental release and incorporation of radiocesium into soil minerals represents a massive environmental, technical and social challenge. Accurately forecasting the evolving distribution and fate of long- and medium-lived isotopes such as 137 Cs and 134 Cs over decadal time scales is essential. The cesium cation has long been modeled as a strongly and selectively sorbed species into clay mineral interlayers; however, because of the time scales involved by the radioisotopes half-lives, the effects of radioactive decay on Cs retention have been unknown. We report density functional theory (DFT) simulations of transmutation effects of radiocesium on long-term Cs retention in phlogopite. The calculations show that the progressive appearance of daughter product Ba 2+ is accompanied by a proportional increase in thermodynamic driving force to preferentially discharge remaining Cs, both radioactive and stable, back into aqueous solution. Based on thermodynamic analysis, the findings indicate that radiocesium transmutation provides a mean to weaken the binding of Cs in phyllosilicate minerals, therefore potentially involving a premature re-release of Cs back into the environment. In the case where radiogenic Ba 2+ ions accumulate in the mineral, collateral effects would ultimately be an increase in the overall interlayer binding energy and a lower resorption capacity.

Relationship between potassium intake and radiocesium retention in the reindeer

International Nuclear Information System (INIS)

Holleman, D.F.; Luick, J.R.

1975-01-01

The effect of dietary potassium on radiocesium retention was studied in reindeer fed winter diets of lichens. Potassium added to the diet markedly decreased radiocesium retention; this suggests that seasonal changes in cesium retention observed earlier in reindeer might be caused largely by nutritional factors. Data indicate that a 20-fold increase in dietary potassium results in a 2-fold decrease in radiocesium retention

Record Retention Practices among the Nation's “Most Wired” Hospitals

OpenAIRE

Rinehart-Thompson, Laurie A.

2008-01-01

This exploratory study examined health record retention practices among health information management professionals in acute care general hospitals in the United States. A descriptive research design was used, and data were collected using a self-reporting survey. Respondents answered questions about record retention policies, the responsibility of health information professionals in policy administration, record retention periods, factors that determine retention periods, and other informati...

Factors That Influence Enrolment and Retention in Ghana' National Health Insurance Scheme.

Science.gov (United States)

Kotoh, Agnes Millicent; Aryeetey, Genevieve Cecilia; Van der Geest, Sjaak

2017-10-17

The government of Ghana introduced the National Health Insurance Scheme (NHIS) in 2004 with the goal of achieving universal coverage within 5 years. Evidence, however, shows that expanding NHIS coverage and especially retaining members have remained a challenge. A multilevel perspective was employed as a conceptual framework and methodological tool to examine why enrolment and retention in the NHIS remains low. A household survey was conducted after 20 months educational and promotional activities aimed at improving enrolment and retention rates in 15 communities in the Central and Eastern Regions (ERs) of Ghana. Observation, indepth interviews and informal conversations were used to collect qualitative data. Forty key informants (community members, health providers and district health insurance schemes' [DHISs] staff) purposely selected from two casestudy communities in the Central Region (CR) were interviewed. Several community members, health providers and DHISs' staff were also engaged in informal conversations in the other five communities in the region. Also, four staff of the Ministry of Health (MoH), Ghana Health Service (GHS) and National Health Insurance Authority (NHIA) were engaged in in-depth interviews. Descriptive statistics was used to analyse quantitative data. Qualitative data was analysed using thematic content analysis. The results show that factors that influence enrolment and retention in the NHIS are multi-dimensional and cut across all stakeholders. People enrolled and renewed their membership because of NHIS' benefits and health providers' positive behaviour. Barriers to enrolment and retention included: poverty, traditional risk-sharing arrangements influence people to enrol or renew their membership only when they need healthcare, dissatisfaction about health providers' behaviour and service delivery challenges. Given the multi-dimensional nature of barriers to enrolment and retention, we suggest that the NHIA should engage DHISs, health

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...

The Association Between Health Program Participation and Employee Retention.

Science.gov (United States)

Mitchell, Rebecca J; Ozminkowski, Ronald J; Hartley, Stephen K

2016-09-01

Using health plan membership as a proxy for employee retention, the objective of this study was to examine whether use of health promotion programs was associated with employee retention. Propensity score weighted generalized linear regression models were used to estimate the association between telephonic programs or health risk surveys and retention. Analyses were conducted with six study samples based on type of program participation. Retention rates were highest for employees with either telephonic program activity or health risk surveys and lowest for employees who did not participate in any interventions. Participants ranged from 71% more likely to 5% less likely to remain with their employers compared with nonparticipants, depending on the sample used in analyses. Using health promotion programs in combination with health risk surveys may lead to improvements in employee retention.

Gatherings as a retention strategy.

Science.gov (United States)

Stokes, Lillian Gatlin

2003-01-01

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

Mechanistic failure mode investigation and resolution of parvovirus retentive filters.

Science.gov (United States)

LaCasse, Daniel; Lute, Scott; Fiadeiro, Marcus; Basha, Jonida; Stork, Matthew; Brorson, Kurt; Godavarti, Ranga; Gallo, Chris

2016-07-08

Virus retentive filters are a key product safety measure for biopharmaceuticals. A simplistic perception is that they function solely based on a size-based particle removal mechanism of mechanical sieving and retention of particles based on their hydrodynamic size. Recent observations have revealed a more nuanced picture, indicating that changes in viral particle retention can result from process pressure and/or flow interruptions. In this study, a mechanistic investigation was performed to help identify a potential mechanism leading to the reported reduced particle retention in small virus filters. Permeate flow rate or permeate driving force were varied and analyzed for their impact on particle retention in three commercially available small virus retentive filters. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:959-970, 2016. © 2016 American Institute of Chemical Engineers.

Colloidal suspensions hydrodynamic retention mechanisms in model porous media

International Nuclear Information System (INIS)

Salehi, N.

1996-01-01

This study deals with the retention mechanisms of colloidal particles in porous media flows, and the subsequent reduction in permeability in the case of stable and non adsorbing colloids. It combines experimental results and modelling. This study has been realised with stable dispersion of monodispersed carboxylate polystyrene latexes negatively charged injected through negatively charged polycarbonate membranes having mono-sized cylindrical pores. The mean particle diameter is smaller than the mean pore diameter. Both batch and flow experiments in Nuclepore membranes have been done. The results of batch experiments have proved no adsorption of the colloidal latex particles on the surface of the Nuclepore membranes without flow at low salinity. In flow experiments at low particle concentration, only deposition on the upstream side of the membrane have been induced by hydrodynamic forces even for non adsorbing particles without creating any permeability reduction. The retention levels are zero at low and high Peclet numbers with a maximum at intermediate values. Partial plugging was observed at higher colloid concentration even at low salinity without any upstream surface deposition. The modelling of plugging processes is achieved by considering the particle concentration, fluid rate and ratio between the mean pore diameter and the mean particle diameter. This study can be particularly useful in the fields of water treatment and of restoration of lands following radioactive contamination. (author). 96 refs., 99 figs., 29 tabs

Improving retention and motivation in non-clinical dialysis employees.

Science.gov (United States)

Campbell, Anne

2004-02-01

For no additional expense, little intrusion into the schedule or duties of the day, and no additional personnel to hire, dialysis facilities can make a dramatic impact on the training, motivation, and retention of employees through the use of classes designed specifically for the needs of newly employed non-clinical personnel. In today's world where many are expected to do a task with little or no orientation to the overall values and goals of the organization and how their tasks matter, what other action can accomplish so much for employee motivation and retention for so little time and expense? At DCI Mid-Missouri this program has been successful in retaining many excellent employees over many years and has been part of an ongoing effort to increase employees' interest and commitment to their work and the organization. It has also made them much more aware of treatments, other personnel and most of all, of our patients and their needs. It fulfills the needs of humans to be valued and have meaningful work. It contains costs and helps efficiency and productivity. Most of all, it keeps excellent people on the job and enjoying their work more than they would have. Participants' words when evaluating the most recent series of classes speak for themselves in demonstrating these important benefits that can be achieved easily in dialysis facilities throughout the United States and the world.

Iodine and fluorine removal of the water using two synthetic adsorbents of great fixation capacity

International Nuclear Information System (INIS)

Neri G, M.; Badillo A, V. E.

2012-10-01

In this work is studied the affinity of two synthetic adsorbents of great fixation capacity, the alumina and the hydroxyapatite, as alternative for the removal of two halogens, iodine and fluorine of the water; the first of importance in the radioactive wastes management and the second of interest in public health. This study was carried out applying the technique of radioactive tracers, with 131 I and the radionuclide 18 F (it produced in the unit PET-cyclotron of the UNAM). The affinity of the synthetic adsorbents for the halogens is expressed in terms of the distribution coefficient and of the retention percent in function of the solution ph. The results obtained for the iodine and fluorine in the synthetic solids are markedly different; in the case of the iodine, the retention is worthless in the whole interval of studied ph while for the fluorine high distribution coefficient and fixation percentages are presented of until 100%. Also for the fluorine in hydroxyapatite high distribution coefficients and superiors are obtained in relation to those that are obtained in the alumina. In both solids the fluorine retention diminishes as the ph of the solution increases, what shows the competition with the hydroxyl ions for the active places in surface. (Author)

Is cunnilingus-assisted orgasm a male sperm-retention strategy?

Science.gov (United States)

Pham, Michael N; Shackelford, Todd K; Sela, Yael; Welling, Lisa Lm

2013-06-06

We secured data from 243 men in committed, sexual, heterosexual relationships to test the sperm retention hypothesis of oral sex. We predicted that, among men who perform cunnilingus on their partner, those at greater risk of sperm competition are more likely to perform cunnilingus until their partner achieves orgasm (Prediction 1), and that, among men who ejaculate during penile-vaginal intercourse and whose partner experiences a cunnilingus-assisted orgasm, ejaculation will occur during the brief period in which female orgasm might function to retain sperm (Prediction 2). The results support Prediction 1 but not Prediction 2. We discuss limitations of the current research and discuss how these results may be more consistent with alternative hypotheses regarding female orgasm and oral sex.

Is Cunnilingus-Assisted Orgasm a Male Sperm-Retention Strategy?