962 resultados para seed retention time
Resumo:
The purpose of this research was to investigate the retention of flavour volatiles encapsulated in water-insoluble systems during high temperature–short time extrusion process. A protein precipitation method was used to produce water-insoluble capsules encapsulating limonene, and the capsules were added to the extruder feed material (cornstarch). A twin-screw extruder was used to evaluate the effect of capsule level of addition (0–5%), barrel temperature (125–145 °C) and screw speed (145–175 r.p.m.) on extruder parameters (torque, die pressure, specific mechanical energy, residence time distribution) and extrudate properties [flavour retention, texture, colour, density, expansion, water absorption index, water solubility index (WSI)]. Capsule level had a significant effect on extrusion conditions, flavour retention and extrudate physical properties. Flavour retention increased with the increase in capsule level from 0% to 2.5%, reached a maximum value at capsule level of 2.5% and decreased when the capsule level increased from 2.5% to 5%. The die pressure, torque, expansion ratio, hardness and WSI exhibited the opposite effect with the presence of capsules.
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Engineering education in the United Kingdom is at the point of embarking upon an interesting journey into uncharted waters. At no point in the past have there been so many drivers for change and so many opportunities for the development of engineering pedagogy. This paper will look at how Engineering Education Research (EER) has developed within the UK and what differentiates it from the many small scale practitioner interventions, perhaps without a clear research question or with little evaluation, which are presented at numerous staff development sessions, workshops and conferences. From this position some examples of current projects will be described, outcomes of funding opportunities will be summarised and the benefits of collaboration with other disciplines illustrated. In this study, I will account for how the design of task structure according to variation theory, as well as the probe-ware technology, make the laws of force and motion visible and learnable and, especially, in the lab studied make Newton's third law visible and learnable. I will also, as a comparison, include data from a mechanics lab that use the same probe-ware technology and deal with the same topics in mechanics, but uses a differently designed task structure. I will argue that the lower achievements on the FMCE-test in this latter case can be attributed to these differences in task structure in the lab instructions. According to my analysis, the necessary pattern of variation is not included in the design. I will also present a microanalysis of 15 hours collected from engineering students' activities in a lab about impulse and collisions based on video recordings of student's activities in a lab about impulse and collisions. The important object of learning in this lab is the development of an understanding of Newton's third law. The approach analysing students interaction using video data is inspired by ethnomethodology and conversation analysis, i.e. I will focus on students practical, contingent and embodied inquiry in the setting of the lab. I argue that my result corroborates variation theory and show this theory can be used as a 'tool' for designing labs as well as for analysing labs and lab instructions. Thus my results have implications outside the domain of this study and have implications for understanding critical features for student learning in labs. Engineering higher education is well used to change. As technology develops the abilities expected by employers of graduates expand, yet our understanding of how to make informed decisions about learning and teaching strategies does not without a conscious effort to do so. With the numerous demands of academic life, we often fail to acknowledge our incomplete understanding of how our students learn within our discipline. The journey facing engineering education in the UK is being driven by two classes of driver. Firstly there are those which we have been working to expand our understanding of, such as retention and employability, and secondly the new challenges such as substantial changes to funding systems allied with an increase in student expectations. Only through continued research can priorities be identified, addressed and a coherent and strong voice for informed change be heard within the wider engineering education community. This new position makes it even more important that through EER we acquire the knowledge and understanding needed to make informed decisions regarding approaches to teaching, curriculum design and measures to promote effective student learning. This then raises the question 'how does EER function within a diverse academic community?' Within an existing community of academics interested in taking meaningful steps towards understanding the ongoing challenges of engineering education a Special Interest Group (SIG) has formed in the UK. The formation of this group has itself been part of the rapidly changing environment through its facilitation by the Higher Education Academy's Engineering Subject Centre, an entity which through the Academy's current restructuring will no longer exist as a discrete Centre dedicated to supporting engineering academics. The aims of this group, the activities it is currently undertaking and how it expects to network and collaborate with the global EER community will be reported in this paper. This will include explanation of how the group has identified barriers to the progress of EER and how it is seeking, through a series of activities, to facilitate recognition and growth of EER both within the UK and with our valued international colleagues.
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In community college nursing programs the high rate of attrition was a major concern to faculty and administrators. Since first semester attrition could lead to permanent loss of students and low retention in nursing programs, it was important to identify at-risk students early and develop proactive approaches to assist them to be successful. The goal of nursing programs was to graduate students who were eligible to take the national council licensing examination (RN). This was especially important during a time of critical shortage in the nursing workforce. ^ This study took place at a large, multi-campus community college, and used Tinto's (1975) Student Integration Model of persistence as the framework. A correlational study was conducted to determine whether the independent variables, past academic achievement, English proficiency, achievement tendency, weekly hours of employment and financial resources, could discriminate between the two grade groups, pass and not pass. Establishing the relationship between the selected variables and successful course completion might be used to reduce attrition and improve retention. Three research instruments were used to collect data. A Demographic Information form developed by the researcher was used to obtain academic data, the research questionnaire Measure of Achieving Tendency measured achievement motivation, and the Test of Adult Basic Education (TABE), Form 8, Level A, Tests 1, 4, and 5 measured the level of English proficiency. The Department of Nursing academic policy, requiring a minimum course grade of “C” or better was used to determine the final course outcome. A stepwise discriminant analysis procedure indicated that college language level and pre-semester grade point average were significant predictors of final course outcome. ^ Based on the findings of the study recommendations focused on assessing students' English proficiency prior to admission into the nursing program, an intensive remediation plan in language comprehension for at-risk students, and the selection of alternate textbooks and readings that more closely matched the English proficiency level of the students. A pilot study should be conducted to investigate the benefit of raising the admission grade point average. ^
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The purpose of this study was twofold: (1) to evaluate the effect of a specific instructional Intervention, a Nursing Theory Laboratory, on increasing the retention of high risk students in the associate degree nursing program at Miami-Dade Community College in Miami, Florida; and (2) to identify predictors of success of high risk nursing students in this associate degree nursing program.^ Data were collected from the 195 nursing students enrolled in Nursing Fundamentals during the 1985-1987 academic years, and identified as high risk students. Control and experimental groups were selected based on enrollment in the Nursing Theory Laboratory.^ Results were determined by analyzing several cross-tabulations of selected variables and yielding chi square values, t-tests, and two discriminant analyses. There was no significant relationship between age or ethnic background and enrollment in the Nursing Theory Laboratory. There was no significant relationship between enrollment in the Nursing Theory Laboratory and success in Nursing 1 (Nursing Fundamentals). There was a significant relationship between enrollment in the Nursing Theory Laboratory and success in Nursing 3 (Medical-Surgical Nursing). Writing assessment test scores in two entrance tests and high risk categories, based on the number of enrollments in required science courses, were identified as predictors of success in this program.^ The conclusion was that the Nursing Theory Laboratory does not significantly improve retention of high risk associate degree nursing students if they are enrolled in this intervention at the same time they are enrolled in Nursing Fundamentals. Since those students who were enrolled in the Nursing Theory Laboratory had a significantly higher success rate in Nursing 3, than those students who were not enrolled in the Nursing Theory Laboratory, a recommendation of this study was to offer the Nursing Theory Laboratory to high risk students prior to the beginning of nursing courses. Another recommendation was that students deficient in reading and writing skills should be required to enroll in developmental courses prior to enrollment in the nursing course. ^
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Increased treatment retention among substance abusing individuals has been associated with reduced drug use, fewer arrests, and decreased unemployment, as well as a reduction in health risk behaviors. This longitudinal study examined the predictors of client retention for alternative to prison substance abuse treatment programs through assessing the roles of motivational factors and the client-worker relationship. The sample was comprised of 141 male felony offenders who were legally mandated to community based long-term residential drug treatment programs. ^ The primary measures used in the study were the consecutive days a participant remained in treatment, Stages of Change Readiness Model and Treatment Eagerness Scale (SOCRATES), the Working Alliance Inventory (WAI), and The Readiness Ruler. Hierarchical multiple regression analysis was conducted for four hypotheses (a) participants who are more motivated to change at the time of entry will remain in treatment longer, (b) participants who have a strong therapeutic alliance will remain in treatment a greater number of consecutive days than participants who have weaker therapeutic alliance, (c) motivation to change, as measured at treatment entry, will be positively related to therapeutic alliance, (d) during the course of treatment variation in motivation to change will be predicted by the therapeutic alliance. ^ Results support the following conclusions: Among clients in alternative-to prison programs the number of days in treatment is positively related to their motivation to change. The therapeutic alliance is not a predictor of the number of days in treatment. Motivation to change, particularly recognition of a drug problem, is positively related to the therapeutic alliance. Changes in motivation to change in response to treatment are positively related to the therapeutic alliance among clients in an alternative to prison substance abuse treatment programs. These results carry forward prior research and have implications for social work practice, research, and social welfare policy. ^
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The rewards and sanctions associated with high-stakes testing may induce educators to participate in practices that will ensure the elimination of the scores of low-achieving students from the testing pool. Two ways in which scores may be eliminated is through retention or referral to special education. ^ This study examined the use of these practices at 179 elementary schools in Miami-Dade County Public Schools, the 4th largest school district in the country. Between- and within-subjects designs were analyzed using repeated measures analysis of variance to compare retention and referral to special education practices over a five-year period of time, two years prior to and two years after the implementation of Florida's high-stakes test, the Florida Comprehensive Assessment Test, FCAT. ^ Significant main effects for referral and retention over time were demonstrated. The use of retention steadily increased over the first three years, with its usage maintained during the fourth year. While the use of referral actually decreased from the first to second years, a significant change occurred after the implementation of the FCAT. ^ Examination of the use of these practices according to student and school characteristics revealed significant differences. Increases in the use of referral across time was significant for Black, non-Hispanic and Hispanic students, all limited English proficiency population categories, medium and low socioeconomic status category schools, all grade levels, and for schools with accountability grades of A. C, D and F with the most striking absolute increase occurring for F schools. Increases in the use of retention across time were significant for all ethnic groups, limited English proficiency categories, and socioeconomic status categories, for grades kindergarten through four and by gender. Significant increases occurred for schools with accountability performance grades of C, D and F; however the most dramatic increase occurred for the F schools. A direct relationship between performance category grade of school and their use of retention was demonstrated. The results suggest that schools changed their use of referral and retention in response to the implementation of the FCAT. ^
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Objective Patients can experience urinary retention (UR) after Holmium laser enucleation of the prostate (HoLEP) that requires bladder distension during the procedure. The aim of this retrospective study is to identify factors affecting the UR after HoLEP. Materials and Methods 336 patients, which underwent HoLEP for a symptomatic benign prostatic hyperplasia between July 2008 and March 2012, were included in this study. Urethral catheters were routinely removed one or two days after surgery. UR was defined as the need for an indwelling catheter placement following a failure to void after catheter removal. Demographic and clinical parameters were compared between the UR (n = 37) and the non-urinary retention (non-UR; n = 299) groups. Results The mean age of patients was 68.3 (±6.5) years and the mean operative time was 75.3 (±37.4) min. Thirty seven patients (11.0%) experienced a postoperative UR. UR patients voided catheter free an average of 1.9 (±1.7) days after UR. With regard to the causes of UR, 24 (7.1%) and 13 (3.9%) patients experienced a blood clot-related UR and a non-clot related UR respectively. Using multivariate analysis (p<0.05), we found significant differences between the UR and the non-UR groups with regard to a morcellation efficiency (OR 0.701, 95% CI 0.498–0.988) and a bleeding-related complication, such as, a reoperation for bleeding (OR 0.039, 95% CI 0.004–0.383) or a transfusion (OR 0.144, 95% CI 0.027–0.877). Age, history of diabetes, prostate volume, pre-operative post-void residual, bladder contractility index, learning curve, and operative time were not significantly associated with the UR (p>0.05). Conclusions De novo UR after HoLEP was found to be self-limited and it was not related to learning curve, patient age, diabetes, or operative time. Efficient morcellation and careful control of bleeding, which reduces clot formation, decrease the risk of UR after HoLEP.
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Institutions have implemented many campus interventions to address student persistence/retention, one of which is Early Warning Systems (EWS). However, few research studies show evidence of interventions that incorporate noncognitive factors/skills, and psychotherapy/psycho-educational processes in the EWS. A qualitative study (phenomenological interview and document analysis) of EWS at both a public and private 4-year Florida university was conducted to explore EWS through the eyes of the administrators of the ways administrators make sense of students' experiences and the services they provide and do not provide to assist students. Administrators' understanding of noncognitive factors and the executive skills subset and their contribution to retention and the executive skills development of at-risk students were also explored. Hossler and Bean's multiple retention lenses theory/paradigms and Perez's retention strategies were used to guide the study. Six administrators from each institution who oversee and/or assist with EWS for first time in college undergraduate students considered academically at-risk for attrition were interviewed. Among numerous findings, at Institution X: EWS was infrequently identified as a service, EWS training was not conducted, numerous cognitive and noncognitive issues/deficits were identified for students, and services/critical departments such as EWS did not work together to share students' information to benefit students. Assessment measures were used to identify students' issues/deficits; however, they were not used to assess, track, and monitor students' issues/deficits. Additionally, the institution's EWS did address students' executive skills function beyond time management and organizational skills, but did not address students' psychotherapy/psycho-educational processes. Among numerous findings, at Institution Y: EWS was frequently identified as a service, EWS training was not conducted, numerous cognitive and noncognitive issues/deficits were identified for students, and services/critical departments such as EWS worked together to share students' information to benefit students. Assessment measures were used to identify, track, and monitor students' issues/deficits; however, they were not used to assess students' issues/deficits. Additionally, the institution's EWS addressed students' executive skills function beyond time management and organizational skills, and psychotherapy/psycho-educational processes. Based on the findings, Perez's retention strategies were not utilized in EWS at Institution X, yet were collectively utilized in EWS at Institution Y, to achieve Hossler and Bean's retention paradigms. Future research could be designed to test the link between engaging in the specific promising activities identified in this research (one-to-one coaching, participation in student success workshops, academic contracts, and tutoring) and student success (e.g., higher GPA, retention). Further, because this research uncovered some concern with how to best handle students with physical and psychological disabilities, future research could link these same promising strategies for improving student performance for example among ADHD students or those with clinical depression.
Resumo:
Increased numbers of students are enrolling in online doctoral programs. Although students enroll for a variety of reasons, many do not persist to the dissertation phase. The results of this quantitative study can guide the development of retention strategies for students who are at risk of academic failure in doctoral programs.
Resumo:
Increased treatment retention among substance abusing individuals has been associated with reduced drug use, fewer arrests, and decreased unemployment, as well as a reduction in health risk behaviors. This longitudinal study examined the predictors of client retention for alternative to prison substance abuse treatment programs through assessing the roles of motivational factors and the client-worker relationship. The sample was comprised of 141 male felony offenders who were legally mandated to community based long-term residential drug treatment programs. The primary measures used in the study were the consecutive days a participant remained in treatment, Stages of Change Readiness Model and Treatment Eagerness Scale (SOCRATES), the Working Alliance Inventory (WAI), and The Readiness Ruler. Hierarchical multiple regression analysis was conducted for four hypotheses (a) participants who are more motivated to change at the time of entry will remain in treatment longer, (b) participants who have a strong therapeutic alliance will remain in treatment a greater number of consecutive days than participants who have weaker therapeutic alliance, (c) motivation to change, as measured at treatment entry, will be positively related to therapeutic alliance, (d) during the course of treatment variation in motivation to change will be predicted by the therapeutic alliance. Results support the following conclusions: Among clients in alternative-to prison programs the number of days in treatment is positively related to their motivation to change. The therapeutic alliance is not a predictor of the number of days in treatment. Motivation to change, particularly recognition of a drug problem, is positively related to the therapeutic alliance. Changes in motivation to change in response to treatment are positively related to the therapeutic alliance among clients in an alternative to prison substance abuse treatment programs. These results carry forward prior research and have implications for social work practice, research, and social welfare policy.
Resumo:
The rewards and sanctions associated with high-stakes testing may induce educators to participate in practices that will ensure the elimination of the scores of low-achieving students from the testing pool. Two ways in which scores may be eliminated is through retention or referral to special education. This study examined the use of these practices at 179 elementary schools in Miami-Dade County Public Schools, the 4th largest school district in the country. Between- and within-subjects designs were analyzed using repeated measures analysis of variance to compare retention and referral to special education practices over a five-year period of time, two years prior to and two years after the implementation of Florida's high-stakes test, the Florida Comprehensive Assessment Test, FCAT. Significant main effects for referral and retention over time were demonstrated. The use of retention steadily increased over the first three years, with its usage maintained during the fourth year. While the use of referral actually decreased from the first to second years, a significant change occurred after the implementation of the FCAT. Examination of the use of these practices according to student and school characteristics revealed significant differences. Increases in the use of referral across time was significant for Black, non-Hispanic and Hispanic students, all limited English proficiency population categories, medium and low socioeconomic status category schools, all grade levels, and for schools with accountability grades of A, C, D and F with the most striking absolute increase occurring for F schools. Increases in the use of retention across time were significant for all ethnic groups, limited English proficiency categories, and socioeconomic status categories, for grades kindergarten through four and by gender. Significant increases occurred for schools with accountability performance grades of C, D and F; however the most dramatic increase occurred for the F schools. A direct relationship between performance category grade of school and their use of retention was demonstrated. The results suggest that schools changed their use of referral and retention in response to the implementation of the FCAT.
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The Hf isotope composition of seawater does not match that expected from dissolution of bulk continental crust. This mismatch is generally considered to be due to retention of unradiogenic Hf in resistant zircons during incomplete weathering of continental crust. During periods of intense glacial weathering, zircons should break down more efficiently, resulting in the release of highly unradiogenic Hf to the oceans. We test this hypothesis by comparing Nd and Hf isotope time series obtained from NW Atlantic ferromanganese crusts. Both isotope systems show a decrease associated with the onset of northern hemisphere glaciation. The observed changes display distinct trajectories in epsilon Nd- epsilon Hf space, which differ from previously reported arrays of bulk terrestrial material and seawater. Such patterns are consistent with the release of highly unradiogenic Hf from very old zircons, facilitated by enhanced mechanical weathering.
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Atomic layer deposition (ALD) of highly conformal, silicon-based dielectric thin films has become necessary because of the continuing decrease in feature size in microelectronic devices. The ALD of oxides and nitrides is usually thought to be mechanistically similar, but plasma-enhanced ALD of silicon nitride is found to be problematic, while that of silicon oxide is straightforward. To find why, the ALD of silicon nitride and silicon oxide dielectric films was studied by applying ab initio methods to theoretical models for proposed surface reaction mechanisms. The thermodynamic energies for the elimination of functional groups from different silicon precursors reacting with simple model molecules were calculated using density functional theory (DFT), explaining the lower reactivity of precursors toward the deposition of silicon nitride relative to silicon oxide seen in experiments, but not explaining the trends between precursors. Using more realistic cluster models of amine and hydroxyl covered surfaces, the structures and energies were calculated of reaction pathways for chemisorption of different silicon precursors via functional group elimination, with more success. DFT calculations identified the initial physisorption step as crucial toward deposition and this step was thus used to predict the ALD reactivity of a range of amino-silane precursors, yielding good agreement with experiment. The retention of hydrogen within silicon nitride films but not in silicon oxide observed in FTIR spectra was accounted for by the theoretical calculations and helped verify the application of the model.
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This study investigated the effects of long-term-enhanced UV-B, and combined UV-B with elevated CO2 on dwarf shrub berry characteristics in a sub-arctic heath community. Germination of Vaccinium myrtillus was enhanced in seeds produced at elevated UV-B, but seed numbers and berry size were unaffected. Elevated UV-B and CO2 stimulated the abundance of V. myrtillus berries, whilst UV-B alone stimulated the berry abundance of V. vitis-idaea and Empetrum hermaphroditum. Enhanced UV-B reduced concentrations of several polyphenolics in V. myrtillus berries, whilst elevated CO2 increased quercetin glycosides in V. myrtillus, and syringetin glycosides and anthocyanins in E. hermaphroditum berries. UV-B x CO2 interactions were found for total anthocyanins, delphinidin-3-hexoside and peonidin-3-pentosidein in V. myrtillus berries but not E. hermaphroditum. Results suggest positive impacts of UV-B on the germination of V. myrtillus and species-specific impacts of UV-B x elevated CO2 on berry abundance and quality. The findings have relevance and implications for human and animal consumers plus seed dispersal and seedling establishment.
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This data set comprises time series of aboveground community plant biomass (Sown plant community, Weed plant community, Dead plant material, and Unidentified plant material; all measured in biomass as dry weight) and species-specific biomass from the sown species of several experiments at the field site of a large grassland biodiversity experiment (the Jena Experiment; see further details below). Aboveground community biomass was normally harvested twice a year just prior to mowing (during peak standing biomass twice a year, generally in May and August; in 2002 only once in September) on all experimental plots in the Jena Experiment. This was done by clipping the vegetation at 3 cm above ground in up to four rectangles of 0.2 x 0.5 m per large plot. The location of these rectangles was assigned by random selection of new coordinates every year within the core area of the plots. The positions of the rectangles within plots were identical for all plots. The harvested biomass was sorted into categories: individual species for the sown plant species, weed plant species (species not sown at the particular plot), detached dead plant material (i.e., dead plant material in the data file), and remaining plant material that could not be assigned to any category (i.e., unidentified plant material in the data file). All biomass was dried to constant weight (70°C, >= 48 h) and weighed. Sown plant community biomass was calculated as the sum of the biomass of the individual sown species. The data for individual samples and the mean over samples for the biomass measures on the community level are given. Overall, analyses of the community biomass data have identified species richness as well as functional group composition as important drivers of a positive biodiversity-productivity relationship. The following series of datasets are contained in this collection: 1. Plant biomass form the Main Experiment: In the Main Experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). 2. Plant biomass from the Dominance Experiment: In the Dominance Experiment, 206 grassland plots of 3.5 x 3.5 m were established from a pool of 9 species that can be dominant in semi-natural grassland communities of the study region. In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 3, 4, 6, and 9 species). 3. Plant biomass from the monoculture plots: In the monoculture plots the sown plant community contains only a single species per plot and this species is a different one for each plot. Which species has been sown in which plot is stated in the plot information table for monocultures (see further details below). The monoculture plots of 3.5 x 3.5 m were established for all of the 60 plant species of the Jena Experiment species pool with two replicates per species like the other experiments in May 2002. All plots were maintained by bi-annual weeding and mowing.