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The short-term stability and function of charcoal in soil and its relevance to Ghanaian subsistence agricultureMaxfield, Tom January 2017 (has links)
Maintaining an adequate level of soil organic matter and nutrients cycling is crucial to the success of any soil management in the humid tropics. Cover crops, compost, or manure additions have been used successfully to supply nutrients to crops but the benefits of such amendments are often short-lived in the tropics, since decomposition rates are high. This study focused on charcoal which, when utilised as a soil amendment is termed ‘biochar’. Throughout this thesis, the terms ‘charcoal’ and ‘biochar’ are used interchangeably depending on the context. Charcoal exhibits physiochemical properties potentially suitable for soil improvement as well as for the safe and long-term storage of carbon in the environment. As a way of investigating its recalcitrance as a carbon store, O:C ratios have been shown to reflect the extent of oxidation and therefore decomposition of charcoal. This study aimed to fill a gap in the research by describing the effects of biochar on the water retention capacity of soil under laboratory conditions. It also provides a detailed snapshot of the first ten years of recalcitrance under natural conditions, using X-Ray Photoelectron Spectroscopy (XPS) to determine elemental oxygen and carbon ratios of whole charcoal fragments and how these are affected by the surrounding environment over time. Mechanisms of oxidation are described, showing how both biotic and abiotic factors influence the degradation of charcoal in the soil. It also investigated how these properties affect the nutrient and water retention capability of charcoals of different ages in the laboratory. Results of charcoal/soil mixtures showed significant reduction in nitrate leachate losses with no reduction in performance over a ten year period of residing in the soil. It was also shown that charcoal addition to a sandy soil resulted in a significantly increased available water content. Both these results were argued to support the idea that charcoal is of potential beneficial amendment to sandy, degraded soils.
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Factors that influence the retention of middle managers in Company AMalinga, Khethukuthula 28 June 2011 (has links)
Company A has experienced high voluntary staff turnover at middle management level between 2007 and 2009. During this period 35% of middle managers have resigned and, this has resulted in significant financial costs being incurred. This research focused on understanding what factors would make the current middle managers stay in Company A’s employment and what the financial impact has been due to these resignations.
The research concluded that career development, people development by line manager, feedback of own work, a line manager who teaches and coaches subordinates, and working with a knowledgeable line manager, were the top five factors that would make the current middle managers stay in Company A’s employment. The research further concludes that there was a gap between Company A’s retention initiatives and what the middle managers actually value, thus the resignations. The research has also established that the middle managers’ resignations have had a significant financial impact on the organisation.
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Retention of employees in a professional services firm through wealth creation initiativesAdewuyi, Adebukola Mutiat 04 September 2012 (has links)
In the professional services industry, it is no secret that people are the greatest assets. The investment in human capital is the core of the business, the dividends of which can never be under-estimated. The continued success of the professional services firm therefore lies in being able to retain that investment within the organisation. The current high rate of turnover within the firm, and in the professional services industry, is indeed a big challenge for management. One that necessitates a review into a variety of ways of keeping the talent within the firm.
This research study was commissioned to look into one of the proposed initiatives for retaining employees; that of wealth creation. The aim was to source the views of employees on wealth creation as a way of increasing the rate of retention or otherwise as well as identify the preferred structure of such a scheme.
The results of the research showed that employees deem financial remuneration to be highly important and would stay with the firm longer if provided with a wealth initiative. There was preference for a short to medium term scheme rather than a long term one, with some particular suggested schemes coming out as preferred favourites than others. Respondents also went further to highlight other factors that were contributing to loss of talent within the firm.
The responses from the survey have been comprehensively analysed and recommendations made on the implementation of the wealth creation scheme. / Graduate School for Business Leadership / (M.B.A.)
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Tecnologias em telhados verdes extensivos: meios de cultura, caracterização hidrológica e sustentabilidade do sistema / Technologies extensive green roofs: culture media, hydrologic characterization and sustainability systemWilles, Jorge Alex 07 October 2014 (has links)
Tanto no meio rural como urbano as novas tendências são de buscar uma melhoria de técnicas e de uso de materiais alternativos buscando-se uma maior sustentabilidade. A utilização de plantas nas paredes e telhados é um dos mais recentes campos da pesquisa ambiental e busca encontrar uma solução ecológica e sustentável para melhorar a qualidade de vida urbana e rural. Uma cobertura verde consiste de um substrato leve e de uma vegetação apropriada, plantada sobre uma base impermeável. Podem conter também camadas adicionais, tais como, um sistema de drenagem e irrigação e uma barreira anti-raízes. Os efeitos positivos da vegetação sobre o ambiente urbano já são bem conhecidos e neste caso da cobertura, diminuem as enxurradas, filtro biológico, redução da poluição do ar, amenizam o calor nas edificações durante o verão e o conservam durante o inverno. Há também benefícios para a fauna, com retorno de espécies que mantêm o equilíbrio biológico local. Essas coberturas podem ter muitas aplicações, como em indústrias, residências, escritórios e outras propriedades comerciais e rurais. Uma criteriosa seleção de plantas permite que a cobertura verde tenha sucesso em condições adversas. Por outro lado, são necessárias pesquisas no sentido de assegurar um meio de cultura que retenha água e ao mesmo tempo proporcione uma boa drenagem para que as raízes não apodreçam, permitindo uma maior gama de espécies de plantas na cobertura. Neste sentido, realizou-se um estudo dos substratos mais abundantes na região, buscando tecnologias apropriadas para a confecção dos telhados verdes e identificando as melhores técnicas de aplicação, de acordo com a necessidade de cada ambiente. Para a realização deste trabalho foram utilizados dez tipos de substratos que foram pré-selecionados de acordo com a disponibilidade no mercado, de mais fácil obtenção e de melhor custo beneficio ambiental. As análises estatísticas utilizam o delineamento experimental inteiramente ao acaso, em esquema fatorial com três repetições e utilizando o programa estatístico SAS para auxiliar na análise e confecção dos gráficos e discussões. Na avaliação do conjunto de características, a turfa marrom (TM) apresentou o menor valor de densidade seca, maior porosidade total, maiores valores de água facilmente disponível, água disponível e capacidade de retenção de água, e mesmo valor de espaço de aeração daquele sugerido como referência sendo um bom material para o uso em telhados verdes, formando compostos com outros materiais e buscando as melhores características e sustentabilidade do sistema. Dentre os substratos comerciais estudados, o substrato para espécies hortícolas (SH) apresentou os maiores valores de capacidade de retenção de água e água disponível para as plantas, possibilitando um maior intervalo entre irrigações ou chuvas, características importantes para o uso em telhados verdes. No entanto, tornam-se necessários mais estudos com a finalidade identificar mais materiais e substratos apropriados para o uso em telhados verdes, levando-se em conta as diferentes características de cada local, tipo de vegetação escolhida, capacidade de suporte da edificação, dentre outro fatores. / Rural and urban new trends seek an improvement in techniques and use of alternative materials for greater sustainability. The use of plants on walls and roofs is one of the newest fields of environmental research, looking for a green and sustainable solution to improve the quality of urban and rural life. A green cover consists of a substrate and appropriate vegetation planted on an impermeable base. It can also contain additional layers, such as a system of drainage and irrigation with an anti-root barrier. The positive effects of roof vegetation on urban environment are well known, as reducing the runoff,acting as a biological filter, reducing air pollution, minimizing heat inside the buildings during summer and maximizing during the winter. There are also benefits to fauna, with the return of various species, maintaining the local biological balance. The coverage can be adapted to industries, homes, offices and other commercial and rural properties. Careful selection of plants allows the green roof to succeed in adverse conditions. In addition, research is necessary to ensure a culture medium that retains water that the same time provides good drainage to prevent root rot, allowing a wider range of plant species in the cover. In this sense, a study was conducted involving the most abundant substrates of our region, seeking appropriate technologies for the manufacture of green roofs and identifying the best application techniques, according to the needs of each environment. For this work ten types of preselected substrates were used according to market availability, easier to obtain and with a better environmental cost/benefit ratio. Statistics of the experimental design was completely randomized in a factorial format with three replications and using the SAS statistical software to assist in the analysis and construction of graphs and discussions. In evaluating the feature of the cover set, brown peat (TM) presented the lowest value of dry density, higher porosity, higher values of easily available water, available water capacity and water retention, and even the amount of aeration space, suggested TM as being a good reference material for use in green roofs. Among the studied commercial substrates, the substrate for horticultural species (SH) showed the highest values of water holding capacity and water available to plants, allowing a longer interval between irrigations or rainfall, an important characteristic for its use on green roofs. However, more studies are needed in order to identify the most suitable materials and for use in green roof substrates, taking into account the different characteristics of each site, vegetation type, bearing capacity of the building, among other factors.
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How to Teach, Lead, and Live Well: A Qualitative In-Depth Interview Study With Eight North Carolina Teacher-Leaders Who FlourishSaunders, Chelsey Lee January 2018 (has links)
The embattled profession of teaching is like a sad song on repeat (Goldstein, 2015). For beyond a decade, research has proliferated a deficit narrative of teaching as a “revolving door” (Ingersoll, 2001, p. 514) or “leaky bucket” (Sutcher, Darling-Hammond, & Carver-Thomas, 2016, p. 2), in which at least 50% of teachers quit within the first 5 years (Ingersoll, Merrill, & Stuckey, 2014). In fact, as teacher attrition increases, the teacher-shortage crisis ravages our hardest-to-serve schools (Sutcher et al., 2016). Today, the number of aspiring teachers has dropped to the lowest it has been in 45 years (Flannery, 2016).
The curiosity driving my research was and is whether it is possible to disrupt this deficit narrative of teaching as America’s most embattled profession (Goldstein, 2015). To do so, my goals have been to learn how eight teacher-leaders describe and understand their own flourishing in their careers, if they do at all, and what are the encouragers of and obstacles to their flourishing. In other words, rather than turn up the volume on the narrative of teachers who fail, flee, and quit the profession, I wondered how, if at all, stories exist of teachers who live, teach, and lead well.
For this study, I derived the term flourishing from Aristotle’s eudemonia or the art of living well and doing well for self and others (Aristotle, 2011, line 1095b). I then crafted the beginnings of a flourishing framework for what it might mean for teacher-leaders to live the good life. Through a cross-disciplinary and integrative literature review (Torraco, 2016), I learned that flourishing most frequently includes experiencing passion, purpose, and practical wisdom in work and life. In response, I sought to examine how, if at all, eight teachers who are also leaders—both formally and informally in their schools and beyond—experience their own flourishing. To clarify, I defined teacher-leaders as teachers who I believe grew into leaders (Drago-Severson, 2016) and are “galvanized by the desire to improve and thus ensure learning for all students” and “driven to experiment, take risks, collaborate, seek feedback, and question their own and others’ practices” (Fairman & Mackenzie, 2015, p. 64). Therefore, the eight teacher-leaders for this study fit Fairman and Mackenzie’s definition. They participated in two programs that I believe are strong holding environments (Drago-Severson, 2013): North Carolina Teaching Fellows, a preservice university program for aspiring teachers, and National Board for Professional Teacher Standards, an in-service development opportunity for experienced teachers with more than 4 years of experience. To be clear, “holding environments” can be relationships and contexts that create developmentally spaces for adults to grow and feel “honored for who they are” (Drago-Severson, 2012, p. 48; Kegan, 1982, p. 115; Winnicott, 1990). The Pillar Practices of teaming, mentorship, collegial inquiry, and inviting teachers to assume leadership are four holding environment (i.e., structures) in which adults can feel well held (supported) and adequately challenged—in order to increase internal capacities (Drago-Severson, 2004, p. 88).
I chose to invite teachers who participated in two teacher-development programs (i.e., North Carolina Teaching Fellows and National Board Certification) specifically because these programs seem to provide holding environments. Researchers have shown teachers who participated in these two programs are among the best and brightest or irreplaceable teacher-leaders whom schools want to keep, or retain, in our classrooms (Henry, Bastian, & Smith, 2012; Jacob, Vidyarthi, & Carroll, 2012; Petty, Good, & Handler, 2016). In fact, all eight teacher-leaders who participated in this study stayed in the profession at least ten years despite the last decade of sociopolitical flux and rising complexity of public schools (Drago-Severson, 2016).
To facilitate this dissertation study, I conducted three in-depth semi-structured interviews and document analysis with each of the eight teacher-leaders who work in Wake County Public School System of North Carolina (32 hours), the 15th largest district in the nation (Hui, 2016). I asked them how they describe and understand flourishing, if they do, throughout their career, with close attention to three distinct points in the trajectory of their career, that is, in the beginning years (1-3 years), during the National Board Certification Process (during or after 4 years of teaching), and within the last academic year, which was also an election year (2016-2017). I also asked how they describe and understand the encouragers of and obstacles to their own flourishing. For data analysis, I coded verbatim transcripts from these in-depth interviews with Dedoose in two analytic cycles (Maxwell, 2013; Miles, Huberman, & Saldaña, 2014; Seidman, 2013). In the first cycle, I completed open/descriptive and theoretical coding, and, in the second, I looked for categories and broader themes to display the data in narrative summaries and profiles for each participant (n = 8). Throughout, I attended to research bias, reactivity, and validity threats through analytic memos, member checks, discrepant data, and inter-coder reliability with my sponsor.
Findings from this qualitative in-depth interview study and document analysis contributed to a framework of understanding flourishing for teacher-leaders. Overall, I learned that to flourish, or to teach, lead, and live well, for the eight teacher-leader participants in my study, the good life meant that they needed to prioritize the purpose of relating with students
(n = 8), as I claimed in Chapter V; cultivate connections with colleagues who share common passions (n = 8), as I claimed in Chapter VI; and reflect with their practical wisdom on their priority to teach well in the midst of the push and pull of leadership entangled in flourishing
(n = 8), as I claimed in Chapter VII.
The implications and recommendations for policy, research, and practice from these claims and findings based on these eight teacher-leader participants are as follows:
1. to re-story excellence in teaching by creating teacher pipelines, development programs, and measurement tools (policy and research) that consider holistic frames of teacher excellence to include flourishing (i.e., do the teachers believe they are committed to teaching, leading, and living well?);
2. to re-center relationships in schools, especially for teachers, by intentionally crafting spaces such as holding environments where teachers, principals, and all educational leaders can grow their internal capacities to deepen relationships with students and colleagues; and
3. to re-frame the tides of teacher-leadership and consider the practical wisdom and time it takes for teachers to discern their own priories, their own balance, and their own flow (i.e., push and pull) of leadership based on their own understanding of their ability to teach and live well.
In conclusion, I offer a beginning model and framework for teacher-leader flourishing in order for future research to explore how, if at all, teachers in different districts and states or of different demographics and levels might describe and understand their own good life.
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An Exploration of Nonprofit Human Service Volunteer Training and RetentionKylie K. Lowenberg-Deboer (5930735) 03 January 2019 (has links)
This study was an exploration of nonprofit human service volunteer training as related to the retention of volunteers. In their pursuit to fulfill client needs, human service nonprofit organizations often rely heavily on volunteers, which emphasizes the need for a better understanding of the means through which organizations may affect positively the retention rates of volunteers. Training long has been thought to be an effective tool for decreasing attrition and engaging volunteers. By investigating the training experiences of volunteers with a focus on retention, this study hoped to further develop the research community’s understanding of how training helps or hinders volunteer retention and may serve as the basis for further research on the link between training design and retention.
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Ultrassom portátil de bexiga: evidências científicas e autoconfiança do enfermeiro / Portable ultrasound bladder: scientific evidence and self confidence of nursesBeatriz Maria Jorge 29 January 2014 (has links)
A assistência de enfermagem na retenção urinária (RU) incorre na importância da avaliação clínica do enfermeiro. O ultrassom portátil de bexiga (US) é um método não-invasivo que permite diagnosticar o problema, avaliar o volume de urina na bexiga, e decidir ou não, pela realização do cateterismo urinário. Este estudo teve como objetivo avaliar o impacto do uso do ultrassom portátil de bexiga na autoconfiança do enfermeiro durante a avaliação do paciente em retenção urinária. Estudo realizado em duas etapas. Etapa 1- Revisão integrativa da literatura realizada nas bases de dados CINAHL, MEDLINE e Web of Science através dos descritores enfermagem, retenção urinária e ultrassom. Foram inclusas as publicações realizadas no período de 2001 a 2011, nos idiomas inglês, português e espanhol que responderam a pergunta da pesquisa. Etapa 2- Estudo descritivo, mediante autorização ética (Parecer P129-12/2012), desenvolvido junto aos enfermeiros de um Centro de Reabilitação de Portugal, com auxílio de Escala de Autoconfiança na Assistência de Enfermagem à Retenção Urinária (EAAERU). Trata-se de uma escala já validada, tipo Likert de 32 itens, agrupados em cinco fatores: medidas prévias a realização do cateterismo voltadas ao preparo do paciente e profissional; comunicação, consentimento e preparo do material para realização do cateterismo urinário; medidas realizadas durante a realização do cateterismo urinário e/ou em situações iatrogênicas; medidas realizadas após a realização e retirada do cateterismo; avaliação objetiva da RU. Foram encontrados os seguintes resultados: Etapa 1 - Dos 234 artigos encontrados, após leitura exaustiva dos títulos e resumos, foram selecionados 21 artigos. Entre eles, 21 (100,0%), todos foram publicados em inglês, 10 (47,6%) em periódicos de enfermagem, 10 (47,6%) em periódicos médicos e 1 (4,7%) em periódico interdisciplinar. Em relação aos níveis de evidência, 1 (4,7%) apresentou nível I, 1 (4,7%) nível II, 9 (42,8%) nível III, 1 (4,7%) nível IV e 9 (42,8%) nível VI. Quanto aos países de publicação: Canadá (19,0%), Estados Unidos da América (19,0%), Inglaterra (19,0%), Noruega (9,5%), Taiwan (9,5%), Itália (9,5%), Austrália (4,7%), Holanda (4,7%) e França (4,7%). O ano que apresentou maior número de publicações foi o de 2005 (28,5%). Todos os artigos demonstram a eficácia e a eficiência do uso do equipamento na avaliação do paciente em retenção urinária. Etapa 2 - Fizeram parte da amostra 40 enfermeiros; a maioria do sexo feminino (62,5%), com idade média de 35,3 anos, que obtiveram o título de Enfermagem entre 1978 e 2010. Entre eles 13 (32,5%) eram especialistas em reabilitação. A maior parte dos enfermeiros referiu que trabalha na profissão há cerca de 20 anos e 23 (57,5%) possuem menos de cinco anos de tempo de experiência no local de trabalho atual. Assim como na escala original para avaliação dos itens da escala foi utilizado o teste do Alpha de Cronbach que demonstrou uma elevada correlação (Valor de Alpha 0,969) de todos os itens da EAAERU. Quanto à análise de correspondência da autoconfiança dos enfermeiros em relação aos cinco fatores propostos pela escala os resultados demonstraram que os enfermeiros referem confiante, muito confiante e completamente confiante para medidas prévias a realização do cateterismo voltadas ao preparo do paciente e profissional; muito confiante e completamente confiante para comunicação, consentimento e preparo do material para realização do cateterismo urinário; muito confiante e completamente confiante para medidas realizadas durante a realização do cateterismo urinário e/ou em situações iatrogênicas; completamente confiante para medidas realizadas após a realização e retirada do cateterismo e pouco confiante e confiante para avaliação objetiva da RU. Conclui-se que o US é um método eficiente e confiável, que supera a investigação de sinais e sintomas clínicos. Permite o diagnóstico precoce, é um procedimento não invasivo, indolor, que utiliza a tecnologia de forma segura e avalia com precisão a necessidade ou não do cateterismo urinário, evitando a distensão excessiva da bexiga urinária e as complicações oriundas desse fato. Conforme os resultados da amostra é possível observar que mesmo com os predicados que o US possui, na assistência de enfermagem a retenção urinária, a avaliação do paciente em RU é o procedimento mais complexo e exerce influência negativa na autoconfiança do enfermeiro / Nursing care in urinary retention (RU) incurs the importance of clinical evaluation of the nurse. The portable bladder ultrasound (US) is a noninvasive method that allows you to diagnose the problem, assess the volume of urine in the bladder and decide whether or not for performing urinary catheterization. This study aimed to evaluate the impact of the use of portable ultrasound bladder for the nurse\'s confidence during patient evaluation in urinary retention. This study was conducted in two stages: Step 1 - Integrative literature review conducted in CINAHL, MEDLINE and Web of Science databases using descriptors of nursing, ultrasound and urinary retention. Publications in the period 2001-2011 in English, Portuguese and Spanish which answered the survey questions. Step 2 - Descriptive study by ethical commitment (Opinion P129- 12/2012), developed together with nurses in a rehabilitation center of Portugal with the aid of Self-Confidence Scale in Nursing Assistance Urinary Retention (EAAERU). This is a validated scale, Likert 32 items, grouped into five factors: previous steps of the catheterization realization focused on patient and professional\'s preparation; communication, consent and preparation of the material for performing urinary catheterization; steps performed during urinary catheterization performing and/or iatrogenic situations; steps taken after the completion of the catheterization and withdrawal; objective evaluation of UR. Were found the following results: Step 1 - Of the 234 articles found, after carefully reading the titles and abstracts, 21 articles were selected. Among them, 21 (100,0%) , were all published in English , 10 ( 47,6 % ) in nursing journals, 10 (47,6%) in medical journals and 1 (4,7%) in interdisciplinary journal. Regarding the levels of evidence , 1 (4,7%) presented level I, 1 (4,7%) level II, 9 (42,8%) level III, 1 (4,7%) level IV and 9 (42,8%) level VI. The countries of publication: Canada (19,0%), United States of America (19,0%), England (19,0%), Norway (9,5%), Taiwan (9,5%), Italy (9,5%), Australia (4,7%), Netherlands (4,7%) and France (4,7%). The year that had the highest number of publications was 2005 (28,5%). All articles demonstrate the effectiveness and efficiency of the use of equipment to assess patients in urinary retention. Step 2 - The sample consisted of 40 nurses, the majority of females (62,5%) with mean age of 35,3 years, who obtained the title of Nursing between 1978 to 2010. Among them, 13 (32,5%) were specialists in rehabilitation. Most nurses reported working in the profession for about 20 years and 23 (57,5%) have less than five years of experience time in the current workplace. As in the original scale for assessment of the scale items the Cronbach\'s Alpha test which showed a high correlation (0,969 Alpha value) of all items SSNAUR. As for the correspondence analysis of the self-confidence of nurses in relation to the five factors proposed by the scale results showed that nurses refer confident, very confident and totally confident to previous steps of the catheterization realization focused on patient and professional\'s preparation; very confident and completely confident to communication, consent and preparation of the material for performing urinary catheterization; very confident and completely confident to steps performed during urinary catheterization performing and/or iatrogenic situations; completely confident to steps taken after the completion of the catheterization and withdrawal; and little confident and confident for objective evaluation of UR. It is concluded that the US is an efficient and reliable method, which overcomes the investigation of clinical signs and symptoms. Allows early diagnosis, is a painless, non-invasive procedure that uses technology in a safe way and assess accurately the need or not urinary catheterization, avoiding excessive distension of the urinary bladder and the complications arising from that fact. As the sample results can be observed that, even with the predicates that the US has, in nursing care for urinary retention, patient assessment in the UR is the most complex procedure and exerts negative influence on the confidence of nurses
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Dinâmica de tebuthiuron e hexazinona em solos sob aplicação de biocarvão / Tebuthiuron and hexazinone fate in soils with biochar amendmentLetícia de Pierri 23 February 2018 (has links)
A aplicação de biocarvão ao solo tem sido divulgada como prática com vantagens agrícolas e ambientais. Devido à sua elevada reatividade, o biocarvão pode interagir com contaminantes orgânicos e inorgânicos do solo, diminuindo o potencial poluidor de elementos tóxicos e pesticidas. Contudo, a eficácia de herbicidas pré-emergentes pode ser anulada devido à presença de biocarvão no solo, o que impõe a necessidade de doses maiores e resulta no aumento do risco de contaminação ambiental. Adicionalmente, pode haver maior persistência de pesticidas no solo devido à retenção e menor disponibilidade das moléculas em solos com biocarvão. As reações que ocorrem entre o biocarvão e os pesticidas dependem das próprias características do solo e da molécula, além do tempo de interação com o solo (aging) e das propriedades intrínsecas ao biocarvão (biomassa de origem, T°C de pirólise e granulometria). O tebuthiuron e a hexazinona são herbicidas com elevado potencial de lixiviação e podem ter seu destino alterado em função da presença de biocarvão no solo. Estas moléculas possuem elevado tempo de meia-vida (t1/2) e biodegradam lentamente no ambiente edáfico. Assim, processos oxidativos avançados (POA) podem acelerar a decomposição dos herbicidas, sendo ainda uma maneira de integrar o biocarvão em processos químicos para a dissipação de poluentes. Objetivou-se avaliar os efeitos da aplicação de biocarvão na dinâmica dos herbicidas tebuthiuron e hexazinona em solos, tendo-se como objetivos específicos: i) verificar o comportamento sortivo desses herbicidas frente à aplicação de biocarvões produzidos a partir de diferentes matérias-primas e T°C de pirólise, incluindo a influência de fatores como o aging dos herbicidas no solo, tamanho das partículas do biocarvão e disponibilidade de carbono orgânico dissolvido (COD) no solo promovida pela adição do biocarvão; ii) avaliar se a interação entre os herbicidas e o biocarvão afeta a eficiência de controle de braquiária (Brachiaria decumbens); iii) analisar a influência do biocarvão na dissipação e lixiviação de tebuthiuron e hexazinona; e iv) identificar o potencial de uso do biocarvão em POA, como suporte para catalisadores metálicos heterogêneos e como fonte de ferro para reações de Fenton, bem como avaliar o desempenho destes materiais na catálise oxidativa de hidrocarbonetos e dos herbicidas. Experimentos de sorção, (verificando a influência de biocarvões de diferentes matérias-primas e T°C de pirólise, aging e granulometria, além da avaliação em solos de texturas contrastantes), bem como de dissipação e lixiviação foram conduzidos, utilizando-se herbicidas radiomarcados. Em paralelo, a liberação de COD pelos biocarvões e pelos solos foi quantificada, enquanto que um experimento de eficiência de controle sobre braquiária em casa de vegetação foi conduzido. Os biocarvões foram, ainda, avaliados quanto ao potencial de uso como suporte para catalisadores metálicos e para reações de Fenton, avaliando-se sua performance para a oxidação dos herbicidas e de hidrocarbonetos. Apesar de não alterar a classe de lixiviação de tebuthiuron e hexazinona em curto prazo, quando considerado o efeito do aging, a presença de biocarvão de palha de cana-de-açúcar 550°C (PC550) no solo, independentemente da granulometria, pode auxiliar no manejo de herbicidas com elevada mobilidade, especialmente em solos de textura arenosa e com baixo teor de carbono. Neste caso, o herbicida tebuthiuron teve sua classificação alterada de \"molécula lixiviável\" (Kd,app < 5,0 L kg-1) para \"molécula não-lixiviável\" (Kd,app > 5,0 L kg-1). No entanto, o biocarvão de dejeto de galinha 350°C (DG350) aumenta o COD do solo, resultando na diminuição da sorção dos herbicidas. A adição dos biocarvões PC550 e DG350 ao solo não modificam a eficiência de controle de braquiária por moléculas altamente solúveis. Doses a partir das doses recomendadas em campo promovem controle eficiente, independentemente da presença ou não de biocarvão no solo. Tebuthiuron e hexazinona são moléculas recalcitrantes no ambiente, sendo muito baixas suas taxas de mineralização e de dissipação, tanto na presença como na ausência dos biocarvões PC550 e DG350. A presença de biocarvão no solo pouco influenciou a dissipação dessas moléculas. Os biocarvões PC550 e DG350 diminuem o potencial de lixiviação da hexazinona no solo de textura areia franca, mas não afetam o movimento vertical do tebuthiuron nas mesmas condições. Apesar do menor potencial para degradação de tebuthiuron e hexazinona em relação à epoxidação de hidrocarbonetos, a inserção do biocarvão para a síntese de catalisadores mostrou-se eficiente e permitiu o emprego deste material em processos de catálise industrial e ambiental, podendo auxiliar para o manejo da remediação de poluentes e contribuindo para expandir o uso do biocarvão. / Biochar amendments to soil has been claimed as a practice with agricultural and environmental advantages. Due to its high reactivity, biochar can interact with organic and inorganic soil contaminants, reducing the pollution potential of toxic elements and pesticides. However, pre-emergent herbicides efficacy can be negatively affected by biochar additions to the soil, which may impose higher doses and increase the environmental contamination risk. In addition, there may be increasing in the pesticide\'s persistence due to retention and lower availability of the molecules induced by biochar amendment to the soil. The interactions between biochar and the pesticides depend on the characteristics of the soil and the herbicide itself, besides the aging and the biochar\'s properties (biomass, pyrolysis T°C and granulometry). Tebuthiuron and hexazinone are herbicides with leaching potential and may have their fate modified due to the presence of biochar in the soil. These molecules have a high half-life time (t1/2) and biodegrade slowly in the environment. Thus, advanced oxidative processes (AOP) can accelerate the decomposition of herbicides and can be a way of incorporate biochar in chemical processes towards pollutants dissipation. We aimed to evaluate the effects of biochar amendments on tebuthiuron and hexazinone dynamics in soils, and the specific objectives were: i) to verify the sorption behavior of these herbicides in response to biochar\'s amendment from different feedstock and pyrolysis T°C, including the influence of factors such as herbicide aging on the soil, biochar particle size and availability of dissolved organic carbon (DOC) in the soil promoted by biochar addition; ii) to evaluate if the interaction between the herbicides and the biochars affects braquiária (Brachiaria decumbens) control efficiency; iii) to analyze the biochars influence on the dissipation and leaching of tebuthiuron and hexazinone; and iv) to identify the potential use of biochar in AOP as heterogeneous metal catalysts support and as a source of iron for Fenton reactions, as well as to evaluate the performance of these materials in oxidative catalysis of hydrocarbons and herbicides. Sorption experiments, (checking the influence of biochars from different feedstocks and pyrolysis T°C, aging and granulometry, as well as accessing the differences among soil textures), and dissipation and leaching experiments were conducted using radiolabeled herbicides. In parallel, the release of DOC by the biochars and soils was quantified, whereas an experiment in a greenhouse for braquiária control was conducted. The biochars were also evaluated for use as metal catalysts supports and for Fenton reactions, evaluating their performance for herbicides and hydrocarbons oxidation. Although it does not change tebuthiuron and hexazinone leaching class in short term, when considering the aging, the sugarcane straw biochar pyrolyzed at 550°C (PC550), regardless of granulometry, may be useful in the management of high mobility herbicides, especially in sandy soils with low carbon content. In this case, tebuthiuron had its classification modified from \"leachable\" (Kd,app < 5.0 L kg-1) for \"non-leachable\" molecule (Kd,app > 5.0 L kg-1). However, the biochar from poultry manure pyrolyzed at 350°C (DG350) increases the DOC content in the soil, resulting in decreased sorption of the herbicides. The additions of PC550 and DG350 to the soil does not modify the control efficiency of braquiária by highly soluble molecules. Doses higher than the recommended ones promote efficient control, regardless of the presence or absence of biochar in the soil. Tebuthiuron and hexazinone are highly recalcitrant molecules in the environment, having low rates of mineralization and dissipation both in the presence or absence of the biochars PC550 and DG350. The biochar application to the soil barely influenced the herbicides dissipation. The biochars PC550 and DG350 decrease the leaching potential of hexazinone in the sandy soil, but do not affect tebuthiuron leaching in the same conditions. Despite the lower potential for tebuthiuron and hexazinone degradation in relation to the epoxidation of hydrocarbons potential, biochar insertion in the synthesis of catalysts has been proved to be efficient, allowing the use of these wastes in industrial and environmental catalysis processes for pollutants remediation purposes and helping to expand the biochar range of uses.
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Verksamma lärare och yrkesmotivation : En kvalitativ studie om vad lärare upplever som motiverande till att stanna kvar i yrket / Active teachers and job retention : A qualitative study of what teachers perceive as motivating to stay in the professionBajrami, Bledar, Hallberg, Simon January 2019 (has links)
Syftet med den här studien var att undersöka vad som upplevs som motiverande för att lärare ska stanna i yrket. Detta har undersökts med hjälp av en kvalitativ metod där semistrukturerade intervjuer har använts. I studien medverkade åtta gymnasielärare från södra Sverige och alla delade med sig av sina egna upplevelser av sin yrkesmotivation. Enligt tidigare forskning har det identifierats tre huvudkategorier av motivation, nämligen yttre, inre och altruistisk motivation. Dessa omfattar i sin tur motivationer som bland annat relationer, egen utveckling och att hjälpa andra. De åtta intervjuer som genomförts har transkriberats och noga analyserats i form av kodning och tolkning av text. Detta för att eftersträva hög validitet och att konfidentialiteten i studien bevaras. Med hjälp av Burnards (1991) tematiska analysmetod har studiens resultat analyserats. Resultatet visade att relationer till kollegor och elever samt att hjälpa andra upplevdes som primära motivationer. I resultatet återfanns alla tre motivationer i yrket, däribland fanns kategorier såsom kollegor, arbetsmiljö, intresse för ämnet och elevers utveckling. Resultatet kan möjligtvis vara till hjälp för skolor i Sverige för att öka motivationen hos lärare, vilket kan öka chanserna till deras kvarhållning i yrket. / The purpose of this study was to investigate what is perceived as motivating for teachers to stay in the profession. This has been investigated with the help of a qualitative method in which semi-structured interviews have been used. In the study, eight high school teachers from southern Sweden participated and all shared their own experiences about what motivates them in the profession. According to previous research, three main categories of motivation have been identified, such as external, internal and altruistic motivation. These in turn includes relationships, own development and helping others. The eight interviews that have been conducted have also been transcribed and carefully analyzed in the form of coding and interpretation of text. Thus to strive for high validity and to maintain the confidentiality of the study. With the help of Burnards (1991) thematic analysis method the study results have been analyzes. The result of the study is on one hand that the relationships with the colleagues and students as well as helping others were perceived as primary motivations. On the other that the result included all three motivations in the profession, such as colleagues, work environment, interest in the subject and student development. Furthermore, the result may be helpful for schools in Sweden to increase the motivation of teachers, which can increase the chances of their retention in the profession.
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Factors That Contribute to Teacher Retention in High-Poverty Middle SchoolsMarston, Tracy 01 May 2014 (has links)
Much research has been conducted on what can be done to retain teachers in education. This study is an examination of what keeps teachers in high-poverty middle schools. The purpose of the study was to examine why teachers choose to stay in high poverty schools. According to Ed. Gov.(1999) high poverty schools are defined as schools that have 75% to 100% of students on free or reduced lunch.
Eight teachers were interviewed from 2 high poverty schools located in the southeastern region of the United States. These teachers had been employed by their school for at least 5 years. Data were gathered and analyzed to reveal why teachers stay in high poverty schools even though the work can be extremely difficult.
This study showed that the teachers interviewed feel working in a high poverty school can be more difficulty due to issues such as behavior and lack of parental involvement. However, rewards such as student growth and the love they develop for the students are worth the extra labor they put into their jobs. The good they find in their jobs seemed to outweigh the bad.
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