882 resultados para Attrition rate


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The unprecedented increase in the number of older adults is expected to increase the burden of osteoporosis on the individual and society. Blacks have been understudied in osteoporosis prevention education research. Although the risk of osteoporosis is low in this population, its consequences are significant. This study employs a two-group experimental design (experimental and wait-list control groups) to evaluate the effect of an osteoporosis education on two osteoporosis prevention behaviors (OPBs) – calcium intake (CI) and physical activity (PA), in a group of community-dwelling Black older adults, 50 years and older resident in South Florida. A final sample of 110 (mean age 70.15 years), 90% female and 10% male completed a battery of questionnaires at two assessment periods. The experimental group participated in six weekly education program sessions immediately following baseline assessment, and the wait-list control group received the education following end of program assessment by all participants. The weekly educational sessions were conducted in social settings (church or senior center) employing constructs of the Revised Health Belief Model. The sessions focused on improving CI; osteoporosis knowledge (OKT), self-efficacy (SE), health beliefs (HB) and PA. Findings revealed significantly greater increase in reported CI (M = 556 mg, Wilks’ λ = .47, F(1,108)=122.97, p< .001, η2=.53), OKT (p< .001), and SE (p< .001) among participants in the experimental compared to the wait-list control group. There was no significant difference between the two groups for PA and most of the HB subscales. OKT and SE were the best predictors of CI, while perceived barrier was a predominant factor predicting PA. Over the study period, a change in SE was the only variable related to changes in both OPBs. Attrition rate was lower than expected, which can be attributed to the settings utilized for the study. These findings support the importance of utilizing a familiar social setting. These results suggested the effectiveness of a program offered in multiple short sessions among this underserved minority population to improve OKT and SE resulting in a change in OPBs (increase in CI). However, there is need to explore alternative strategies to improve PA in this population group.

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Background: An extensive research literature has documented the impact of caring for an individual with acquired brain injury (ABI) on caregivers and family members, including role adjustment, psychological distress, social isolation, family tension and coping with the cognitive and behavioural difficulties of the injured person. Given these findings it is important this population have access to services and supports. Acceptance and Commitment Therapy (ACT) is an intervention that helps individuals to accept difficult experiences and commit to behaviour that is consistent with their values. Research into the effectiveness of ACT to support caregivers is at a preliminary stage. Aim: To investigate the feasibility of using ACT to reduce psychological distress and increase psychological flexibility in ABI caregivers. A secondary aim was to gain an understanding of the experience of caregivers in this context and how this can inform the development and delivery of interventions for this population. Method: Phase one was a randomised controlled feasibility trial of an ACT intervention for use with ABI caregivers. The parameters of this study were formulated around the PICO (population, intervention, control, and outcome) framework. Eighteen carers were recruited and randomised to ACT or an enhanced treatment as usual (ETAU) group. ACT was implemented over 3 sessions; and ETAU was implemented over 2 sessions. The General Health Questionnaire, Valuing Questionnaire, Acceptance and Action Questionnaire, Experiential Avoidance of Caregiving Questionnaire and the Flexibility of Responses to Self-Critical Thoughts Scale were administered to both groups at baseline and following the final session. Phase two used a retrospective qualitative design that involved conducting semi-structured interviews with four participants from phase one. Results: ACT and control participants were successfully recruited. Positive feedback was obtained from ACT participants suggesting that the intervention was acceptable. There were no significant differences between the ACT and ETAU groups on outcome measures. However, there were challenges retaining participants and the overall attrition rate was high (44.44%). Therefore a number of participants did not complete the full complement of sessions, which may have impacted on this result. Qualitative results illustrated the challenges this population face including significant adjustments in their life, the emotional impact of having a loved one with a brain injury and trying to adapt to the changes in the injured person. In addition, findings elucidated the types of support that this population would find helpful and the barriers to accessing same. Conclusions: Findings from this study highlight factors that will help the development of this intervention further for a caring population. Recommendations for future implementation include completing some preparatory work with carers before beginning the intervention, consideration of a larger sample and wider recruitment strategy from local services, barriers to attending interventions and the possibility of holding groups in local venues.

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Em outubro de 2012, a Direção de Análise e Gestão da Informação (DAGI), em colaboração com a Superintendência do Pessoal (SP) e Direção do Pessoal (DP), iniciou o desenvolvimento de um protótipo de simulador, que designou por “Protótipo Fluxo de Carreiras”. Este simulador permite parametrizar diversos fatores que condicionam o desenvolvimento de carreira dos militares e que estão associados a mecanismos reguladores de carreira que se encontram vertidos no Estatuto dos Militares das Forças Armadas (EMFAR). Para cada ano do período de simulação, a situação de cada militar de uma determinada classe é atualizada e são verificadas as condições para a ocorrência de promoções e passagens à reserva. O evento “passagem à reserva” de um militar pode ter origem em regras determinísticas (exemplo: militar atinge a idade limite de passagem à reserva no seu posto) ou em condições estocásticas ou aleatórias (exemplos: óbito, exclusão da promoção, requerer voluntariamente a passagem à reserva, etc.). Estas últimas situações resultam do fenómeno de erosão dos quadros que pode ser observado a partir do histórico de saídas desta natureza. Até 2015, o simulador de carreiras não comtemplava um modelo de erosão, pelo que os resultados disponibilizados (indicadores de fluxo de carreira) dependiam exclusivamente de mecanismos determinísticos. Desta forma estes resultados apresentam uma natureza “pessimista” e com fraca aderência à realidade. O presente trabalho tem como objetivo construir um modelo descritivo da erosãodos militares oficiais da Marinha, tendo por base dados de saídas (excetuando saídas relacionadas com regras determinísticas previstas no EMFAR) no período de 2008 a2015. Para cada classe da categoria de oficiais é estimada uma função de probabilidadecondicional ao tempo de serviço efetivo ou à idade do militar que representa apropensão para um militar sair do quadro antes de ser verificada uma condição determinística. Estas funções foram integradas no simulador de carreiras para que os resultados possam reproduzir a componente de erosão. Usando o método de simulação de Monte Carlo é possível obter a distribuição dos indicadores de fluxo de carreira. Porfim, objetiva-se realizar uma comparação entre uma simulação com fatores estocásticos (com erosão) e uma simulação considerando apenas fatores determinísticos (semerosão). Este trabalho visa refletir o panorama atual da erosão de pessoal na Marinha, permitindo assim melhorar a qualidade das previsões de efetivos ao longo do tempo bem como aumentar a capacidade de intervenção e resposta na identificação e correção antecipada de possíveis estruturações.

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Expertise in physics has been traditionally studied in cognitive science, where physics expertise is understood through the difference between novice and expert problem solving skills. The cognitive perspective of physics experts only create a partial model of physics expertise and does not take into account the development of physics experts in the natural context of research. This dissertation takes a social and cultural perspective of learning through apprenticeship to model the development of physics expertise of physics graduate students in a research group. I use a qualitative methodological approach of an ethnographic case study to observe and video record the common practices of graduate students in their biophysics weekly research group meetings. I recorded notes on observations and conduct interviews with all participants of the biophysics research group for a period of eight months. I apply the theoretical framework of Communities of Practice to distinguish the cultural norms of the group that cultivate physics expert practices. Results indicate that physics expertise is specific to a topic or subfield and it is established through effectively publishing research in the larger biophysics research community. The participant biophysics research group follows a learning trajectory for its students to contribute to research and learn to communicate their research in the larger biophysics community. In this learning trajectory students develop expert member competencies to learn to communicate their research and to learn the standards and trends of research in the larger research community. Findings from this dissertation expand the model of physics expertise beyond the cognitive realm and add the social and cultural nature of physics expertise development. This research also addresses ways to increase physics graduate student success towards their PhD. and decrease the 48% attrition rate of physics graduate students. Cultivating effective research experiences that give graduate students agency and autonomy beyond their research groups gives students the motivation to finish graduate school and establish their physics expertise.

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Alzheimer’s disease (AD) is the most common form of dementia, currently affecting more than 50 million people worldwide. In recent years attention towards this disease has risen in search for discovery and development of a drug that can stop it. Indeed, therapies for AD provide only temporary symptomatic relief. The cause for the high attrition rate for AD drug discovery has been attributed to several factors, including the fact that the AD pathogenesis is not yet fully understood. Nevertheless, what is increasingly recognized is that AD is a multifactorial syndrome, characterized by many conditions which may lead to neuronal death. Given this, it is widely accepted that a molecule able to modulate more than one target would bring benefit to the therapy of AD. In the first chapter of this thesis, there are reported two projects regarding the design and synthesis of new series of GSK-3/HDAC dual inhibitors, two of the main enzymes involved in AD. Two different series of compounds were synthesized and evaluated for their inhibitory activity towards the target enzymes. The best compounds of the series were selected for further biologic investigation to evaluate their properties. The second project focused on the design of non ATP-competitive GSK-3 inhibitors combined with HDAC inhibition properties. Also in this case, the best compounds of the series were selected for biologic investigation to further evaluate their properties. In chapter 2, the design and synthesis of a GSK-3-directed Proteolysis Targeting Chimeras (PROTAC), a new technology in drug discovery that act through degradation rather than inhibition, is reported. The design and synthesis of a small series of GSK-3-directed PROTACs was achieved. In vitro assays were performed to evaluate the GSK-3-degradation ability, the effective involvement of E3 ubiquitine ligase in the process and their neuroprotective abilities.

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Fine powders of minerals are used commonly in the paper and paint industry, and for ceramics. Research for utilizing of different waste materials in these applications is environmentally important. In this work, the ultrafine grinding of two waste gypsum materials, namely FGD (Flue Gas Desulphurisation) gypsum and phosphogypsum from a phosphoric acid plant, with the attrition bead mill and with the jet mill has been studied. The ' objective of this research was to test the suitability of the attrition bead mill and of the jet mill to produce gypsum powders with a particle size of a few microns. The grinding conditions were optimised by studying the influences of different operational grinding parameters on the grinding rate and on the energy consumption of the process in order to achieve a product fineness such as that required in the paper industry with as low energy consumption as possible. Based on experimental results, the most influential parameters in the attrition grinding were found to be the bead size, the stirrer type, and the stirring speed. The best conditions, based on the product fineness and specific energy consumption of grinding, for the attrition grinding process is to grind the material with small grinding beads and a high rotational speed of the stirrer. Also, by using some suitable grinding additive, a finer product is achieved with a lower energy consumption. In jet mill grinding the most influential parameters were the feed rate, the volumetric flow rate of the grinding air, and the height of the internal classification tube. The optimised condition for the jet is to grind with a small feed rate and with a large rate of volumetric flow rate of grinding air when the inside tube is low. The finer product with a larger rate of production was achieved with the attrition bead mill than with the jet mill, thus the attrition grinding is better for the ultrafine grinding of gypsum than the jet grinding. Finally the suitability of the population balance model for simulation of grinding processes has been studied with different S , B , and C functions. A new S function for the modelling of an attrition mill and a new C function for the modelling of a jet mill were developed. The suitability of the selected models with the developed grinding functions was tested by curve fitting the particle size distributions of the grinding products and then comparing the fitted size distributions to the measured particle sizes. According to the simulation results, the models are suitable for the estimation and simulation of the studied grinding processes.

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The rotary valve is a widely used mechanical device in many solids-handling industrial processes. However, it may also be responsible for most of the attrition effects occurring in a typical process. In this study, the attrition effects occurring in a rotary valve operating as a stand-alone device and as part of a pneumatic conveying system were investigated. In the former case granular attrition was carried out at three different rotary valve speeds and the experimental results obtained were found to be in good agreement with the Gwyn correlation. In the latter case three typical air flow rates were used in the pneumatic conveying system. The size distribution of the attrition product obtained at the lowest air flow rate used was not adequately described by the Gwyn correlation. The attrition process and mechanisms involved were analysed and the minimum size of the attrition product obtained from both modes of operations was found to be similar.

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Background. There is currently a push to increase the number of minorities in cancer clinical trials in an effort to reduce cancer health disparities. Overcoming barriers to clinical trial research for minorities is necessary if we are to achieve the goals of Healthy People 2010. To understand the unexpectedly high rate of attrition in the A NULIFE study, the research team examined the perceived barriers to participation among minority women. The purpose of this study was to determine if either personal or study-related factors influenced healthy pre-menopausal women aged 25-45 years to terminate their participation in the A NULIFE Study. We hypothesized that personal factors were the driving forces for attrition rates in the prevention trial.^ Methods. The target population consisted of eligible women who consented to the A NULIFE study but withdrew prior to being randomized (N= 46), as well as eligible women who completed the informed consent process for the A NULIFE study and withdrew after randomization (N= 42). Examination of attrition rates in this study occurred at a time point when 10 out of 12 participant groups had completed the A NULIFE study. Data involving the 2 groups that were actively engaged in study activities were not used in this analysis. A survey instrument was designed to query the personal and study-related factors that were believed to have contributed to the decision to terminate participation in the A NULIFE study.^ Results. Overall, the highest ranked personal reason that influenced withdrawal from the study was being “too busy” with other obligations. The second highest ranked factor for withdrawal was work obligations. Whereas, more than half of all participants agreed that they were well-informed about the study and considered the study personnel to be approachable, 54% of participants would have been inclined to remain in the study if it were located at a local community center.^ Conclusions. Time commitment was likely a major factor for withdrawal from the A NULIFE study. Future investigators should implement trials within participant communities where possible. Also, focus group settings may provide detailed insight into factors that contribute to the attrition of minorities in cancer clinical trials.^

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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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Principal attrition is a national problem particularly in large urban school districts. Research confirms that schools that serve high proportions of children living in poverty have the most difficulty attracting and retaining competent school leaders. Principals who are at the helm of high poverty schools have a higher turnover rate than the national average of three to four years and higher rates of teacher attrition. This leadership turnover has a fiscal impact on districts and negatively affects student achievement. Research identifies a myriad of reasons why administrators leave the role of principal: some leave the position for retirement; some exit based on difficulty of the role and lack of support; and some simply leave for other opportunities within and outside of the profession altogether. As expectations for both teacher and learner performance drive the national education agenda, understanding how to keep effective principals in their jobs is critical. This study examined the factors that principals in a large urban district identified as potentially affecting their decisions to stay in the position. The study utilized a multi-dimensional, web-based questionnaire to examine principals’ perceptions regarding contributing factors that impact tenure. Results indicated that: • having a quality teaching staff and establishing a positive work-life balance were important stay factors for principals; • having an effective supervisor and collegial support from other principals, were helpful supports; and • having adequate resources, time for long-term planning, and teacher support and resources were critical working conditions. Taken together, these indicators were the most frequently cited factors that would keep principals in their positions. The results were used to create a framework that may serve as a potential guide for addressing principal retention.

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The high rate of teacher attrition in urban schools is well documented. While this does not seem like a problem in Carter County, this equates to hundreds of teachers that need to be replaced annually. Since school year (SY) 2007-08, Carter County has lost over 7,100 teachers, approximately half of (50.1%) of whom resigned, often going to neighboring, higher-paying jurisdictions as suggested by exit survey data (SY2016-2020 Strategic Plan). Included in this study is a range of practices principals use to retain teachers. While the role of the principal is recognized as a critical element in teacher retention, few studies explore the specific practices principals implement to retain teachers and how they use their time to accomplish this task. Through interviews, observations, document analysis and reflective notes, the study identifies the practices four elementary school principals of high and relatively low attrition schools use to support teacher retention. In doing so, the study uses a qualitative cross-case analysis approach. The researcher examined the following leadership practices of the principal and their impact on teacher retention: (a) providing leadership, (b) supporting new teachers, (c) training and mentoring teaching staff, (d) creating opportunities for collaboration, (d) creating a positive school climate, and (e) promoting teacher autonomy. The following research questions served as a foundational guide for the development and implementation of this study: 1. How do principals prioritize addressing teacher attrition or retention relative to all of their other responsibilities? How do they allocate their time to this challenge? 2. What do principals in schools with low attrition rates do to promote retention that principals in high attrition schools do not? What specific practices or interventions are principals in these two types of schools utilizing to retain teachers? Is there evidence to support their use of the practices? The findings that emerge from the data revealed the various practices principals use to influence and support teachers do not differ between the four schools.

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Since insect species are poikilothermic organisms, they generally exhibit different growth patterns depending on the temperature at which they develop. This factor is important in forensic entomology, especially for estimating postmortem interval (PMI) when it is based on the developmental time of the insects reared in decomposing bodies. This study aimed to estimate the rates of development, viability, and survival of immatures of Sarcophaga (Liopygia) ruficornis (Fabricius 1794) and Microcerella halli (Engel 1931) (Diptera: Sarcophagidae) reared in different temperatures: 10, 15, 20, 25, 30, and 35 ± 1 °C. Bovine raw ground meat was offered as food for all experimental groups, each consisting of four replicates, in the proportion of 2 g/larva. To measure the evolution of growth, ten specimens of each group were randomly chosen and weighed every 12 h, from initial feeding larva to pupae, and then discarded. Considering the records of weight gain, survival rates, and stability of growth rates, the range of optimum temperature for the development of S. (L.) ruficornis is between 20 and 35 °C, and that of M. halli is between 20 and 25 °C. For both species, the longest times of development were in the lowest temperatures. The survival rate at extreme temperatures (10 and 35 °C) was lower in both species. Biological data such as the ones obtained in this study are of great importance to achieve a more accurate estimate of the PMI.

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The electrocardiogram (ECG) is the simplest and most effective non-invasive method to assess the electrical activity of the heart and to obtain information on the heart rate (HR) and rhythm. Because information on the HR of very small reptiles (body mass <10 g) is still scarce in the literature, in the present work we describe a procedure for recording the ECG in non-anesthetized geckos (Hemidactylus mabouia, Moreau de Jonnès, 1818) under different conditions, namely manual restraint (MR), spontaneous tonic immobility (TI), and in the non-restrained condition (NR). In the gecko ECG, the P, QRS and T waves were clearly distinguishable. The HR was 2.83 ± 0.02 Hz under MR, which was significantly greater (p < 0.001) than the HR under the TI (1.65 ± 0.09 Hz) and NR (1.60 ± 0.10 Hz) conditions. Spontaneously beating isolated gecko hearts contracted at 0.84 ± 0.03 Hz. The in vitro beating rate was affected in a concentration-dependent fashion by adrenoceptor stimulation with noradrenaline, as well as by the muscarinic cholinergic agonist carbachol, which produced significant positive and negative chronotropic effects, respectively (p < 0.001). To our knowledge, this is the first report on the ECG morphology and HR values in geckos, particularly under TI. The methodology and instrumentation developed here are useful for non-invasive in vivo physiological and pharmacological studies in small reptiles without the need of physical restraint or anesthesia.

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This paper proposes a methodology to predict benzene uptake rate in ambient air, using passive samplers with Tenax TA. Variations in the uptake rate were found to occur as a function of the sampling time; and were greater at the beginning of sampling. An empirical model was obtained and values for uptake rate agree with literature. Concentration prediction errors can be minimized by using sampling times of 4 to 14 days, thus avoiding the influence of excessive uptake rates in the initial days and the influence of back diffusion at the end of the sampling period.