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Mudanças no uso e cobertura do solo na Amazônia e suas implicações no ciclo de nitrogênio / Land-use and land-cover changes in the Amazon and their implications for the nitrogen cycleFigueira, Adelaine Michela e Silva 20 October 2006 (has links)
O estudo da dinâmica de áreas alteradas na Amazônia pode contribuir para a elucidação dos possíveis impactos dos atuais modelos de uso do solo sobre o sistema florestal bem como sua capacidade de recuperação ao longo do tempo, permitindo assim, que sejam feitas previsões quanto ao futuro ambiental da região. O objetivo deste trabalho foi investigar a dinâmica de nitrogênio ao longo de florestas secundárias formadas pela agricultura de corte e queima no município de São Francisco do Pará, e ao longo de clareiras formadas pela exploração seletiva de madeira na Floresta Nacional do Tapajós, ambas no Estado do Pará. Foram selecionadas florestas secundárias de diferentes idades (6, 20 e 40 anos) e clareiras de diferentes idades de formação (1, 3 e 5 anos) bem como áreas de florestas de terra-firme não perturbadas. Nestas áreas, foram avaliadas a abundância natural de 15N e concentrações de N e C em solo, serapilheira e vegetação. Nas clareiras e floresta não perturbada em áreas de exploração seletiva também foram realizados experimentos de mineralização e nitrificação. De um modo geral, todas as áreas investigadas apresentaram um aumento nos valores de &23515N no solo de acordo com a profundidade. Ao longo da cronossequência de florestas secundárias foi observado um aumento no ð15N e na concentração de N foliar, assim como uma diminuição na razão C/N foliar. As concentrações de N foliar foram maiores em espécies de leguminosas e a razão C/N foi mais elevada em espécies de não leguminosas em todas as áreas amostradas. O ð15N da serapilheira também aumentou com a idade da vegetação. Estes resultados indicam que as florestas secundárias tornam-se mais ricas em N à medida que o sistema recupera-se da perturbação, sugerindo uma mudança na ciclagem de N, de mais fechada nos primeiros estágios da sucessão, à mais aberta à medida que esta se aproxima da fisionomia original. Já na área de exploração seletiva de madeira, foram observadas menores taxas de mineralização e nitrificação nas clareiras de 1 ano, porém estas taxas não diferiram entre as demais idades de clareira e entre estas e a floresta de terra-firme. Os valores de ð15N foliar não diferiram entre as áreas, nem entre leguminosas e não-leguminosas dentro de uma mesma área, no entanto, as concentrações de N foliar foram maiores em espécies de leguminosas em todas as áreas amostradas e a razão C/N foi mais elevada em espécies de não leguminosas. Estes fatores indicam a ocorrência de uma ciclagem aberta de N nestas áreas independentemente da perturbação, sugerindo assim, que impactos, como a abertura de uma clareira em florestas ricas em N, não sejam de intensidade suficiente a ponto de causar uma alteração significativa na ciclagem de N nestas áreas, como o que foi observado no estudo enfocando as florestas secundárias estabelecidas em áreas previamente utilizadas para agricultura, onde a perturbação no sistema foi mais intensa. / The study of nutrient dynamics in disturbed areas of the Amazon region helps to provide understanding of how the current land-use models affect the forest ecosystem and its capacity to recover over time. The object of this study was to investigate the nitrogen dynamics along a chronosequence of secondary forests (6, 20 and 40 yearold), following slash-and-burn agriculture that occurred in the municipality of São Francisco do Pará, and along gaps in different stages of development (1,3 and 5 yearold) created by selective logging in the Tapajós National Forest, both in the state of Pará. In order to understand the effects of land cover changes in the nitrogen cycle, we investigated the ð15N, C and N concentrations in soil, litter, and vegetation in these areas. At the selective logging sites, mineralization and nitrification rates were measured. All sites showed an increase in ð15N values in the soil, correlated with depth, in the first 50 cm. There were significant increases in ð15 N and N concentrations in the vegetation along the chronosequence of secondary forests and a decrease in the C/N ratio. The litter ð15N measurements also increased with secondary forest age. These parameters suggest an increasing N availability with stand age. That is, nitrogen cycling is more closed due to N limitation during the first stages of secondary succession, and becomes more open as the secondary forest ages and as rates of N cycling accelerate. At the selective logging sites, mineralization and nitrification rates were lower in the oneyear gap. However, differences were not found within the other gap ages and between those gaps and the undisturbed forest. Significant differences in the foliar ð15N were not found among the various areas, including legume and non-legume groups that belong to a common area. Foliar N contents were greater in legume than in non-legume species and the C/N ratio was higher in the non-legume species in all areas. Nevertheless, these parameters did not differ among the overall areas. These results indicate an open nitrogen cycle occurring in these areas, suggesting that disturbances such as canopy opening in forests originally enriched in nitrogen, are not strong enough to alter significantly this nutrient cycling, as is the conversion of mature to secondary forest through slash and burn agriculture.
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A critical review of graduate employability skills : lessons from the Maltese experienceThake, Anne Marie January 2017 (has links)
This study examines how institutional actors interpret, influence and respond to skills availability in the labour market for graduates. It researches and draws lessons from the Maltese experience of managing graduate employability over three decades, focusing on the three fastest-growing economic sectors, namely, Accountancy, Pharmachem and ICT, each of which is the subject of a case study. The study investigates the interaction of governments, firms, higher education institutions and professional associations in identifying skills shortages and gaps, as well as in devising policy frameworks and skills regimes at national, sectoral and corporate levels. Drawing upon theories of employability and employee skills, first, there is development of an analytical framework to examine how these institutional actors affect the labour market, which informs the analysis of the three case studies. The qualitative research involved an interpretative analysis of key policy documents related to graduate employability and seventy in-depth interviews with interlocutors positioned in strategic policy making, senior management, academic, expert and professional leadership roles within government, regulators, major corporations, higher education institutions, training providers and professional associations. The data was thematically analysed. Twelve key themes emerged from the in-depth interviews, which included the following: use of different language; the meaning of employability; the value of credentials; the role of the University; perceptions; expectations; competitiveness; modes of training provision; labour mobility; placements and incentives; collaboration and skills gap. The institutional actors across the three focal sectors, namely, accountancy, pharmachem and ICT tended to emphasise some themes more than others, these having previously been identified in scholarly literature (Appendix 1). Both patterns and inconsistencies emerged from a comparison of the accountancy, pharmachem and ICT sectors. In so far as the labour market is concerned, the study revealed a lack of technical skills and major non-technical graduate skills gaps, specifically, in the aspects of communication, teamwork and problem-solving. A number of professional characteristics or behaviours were also identified as lacking with Accountancy, Pharmachem and ICT graduates, namely, attitude, confidence, drive, professional outlook, independent working, personality fit and a ‘can do’ approach. The study revealed the absence of permanent systemic connections between the formulation of national and sectoral economic strategies on the one hand, and higher education and training policies on the other. Consequently, state higher education institutions have been responding reactively to labour market needs, which could explain the endemic skills gap which the study found. The study concludes by discussing limitations and limits to this research as well as recommending policy initiatives and further research that could contribute to the science and practice of public policy in this field.
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O uso do ultra-som pulsado de baixa intensidade em falhas ósseas produzidas experimentalmente em rádio de coelhos, preenchdas ou não com cimento de fosfato de cálcio /Moraes, Paola Castro. January 2006 (has links)
Orientador: João Guilherme Padilha Filho / Banca: Claudia Acosta Duarte / Banca: Fabrício Bernardo de Jesus Brasil / Banca: Júlio Carlos Canola / Banca: Márcia Rita Fernandes Machado / Resumo: Foi utilizado na presente pesquisa o ultra-som pulsado de baixa intensidade, com a finalidade de avaliar, experimentalmente, seus efeitos sobre a reparação de falhas ósseas produzidas em rádio de coelhos, preenchidas ou não com o cimento de fosfato de cálcio adicionado com fibras de náilon. Foram utilizados 12 coelhos, raça Nova Zelândia, separados em dois grupos experimentais iguais (n=6) e escolhidos aleatoriamente (Grupo Tratado- GT e Grupo Controle-GC). As falhas ósseas de aproximadamente oito milímetros de extensão foram produzidas na diáfise de ambos os rádios, sendo as do membro direito preenchidas com o cimento de fosfato de cálcio sob a forma granulada e as do esquerdo, não preenchidas. Os animais do grupo tratado receberam estímulo pelo ultra-som pulsado de baixa intensidade durante 15 minutos nos primeiros cinco dias e dez minutos nos cinco dias seguintes, em ambos os membros. Os animais do grupo controle não foram estimulados pelo ultra-som. O controle radiográfico foi realizado no pós-operatório imediato e aos sete, 15 e 30 dias, de acordo com o tempo de observação de cada subgrupo (15 e 30 dias). Após o sacrifício, as áreas que continham as falhas ósseas foram processadas para a avaliação histopatológica. Os resultados das análises radiográfica e histolopatológica revelaram uma evolução mais rápida e intensa da proliferação de tecido ósseo nas falhas, preenchidas ou não pelo cimento, porém que receberam estímulo pelo ultra-som. Os resultados obtidos neste trabalho mostraram que o ultra-som pulsado de baixa intensidade é ser um recurso extremamente eficaz na aceleração do processo de ossificação e que, associado ao cimento de fosfato de cálcio com fibras de náilon, tem este processo intensificado, demonstrando, assim, o poder osteoindutor deste biomaterial. / Abstract: The present experimental research evaluated the effects of low intensity pulsed ultrasound for repair bone defects produced in rabbit's radius, filled in or not with calcium phosphate cement incorporated with nylon fibers. Twelve rabbits, from the New Zealand lineage, were randomly allocated in two equal experimental groups. An eight millimeters bone gap was surgically produced in the radius bone diaphysis and filled with the cement (right radius). The left limb bone gap remained empty. Animais were submitted to dessions of pulsed ultrasonic stimulus for 15 minutes during five days and ten minutes during more five days, in both radius. Radiological examinations were performed in the immediate postoperative and seven, 15 and 30 days after surgery (according with the postoperative follow-up -15 and 30 days). The bone defects were collected and submitted to optical microscopy. The results showed an increase and faster evolution of ossification's process in the bone defects, filled or not with the bone cement, but that received stimulus by ultrasound when compared to the control group. These results suggest that low-intensity pulsed ultrasound is an effective resource for acceleration of the ossification process and, when combined with calcium phosphate cement, this effect was increased. / Doutor
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Three essays on tax compliance and the estimation of income-gapsGonzalez Cabral, Ana Cinta January 2017 (has links)
Quoting James Andreoni, `the problem of tax compliance is as old as taxes themselves'. The sources of missing tax revenues have traditionally concerned tax administrations and particularly now in times when public finances are striving. In the quest for analysing the revenue that is foregone, tax administrations have started to produce a report of their tax gap, understood as the difference between the theoretical tax liability and the actual collection, to obtain a measure of the extent of non-compliance. Due to the complexity of the non-compliance behaviour and the lack of visibility of certain types of income, different methods are usually put in place in order to offer a plausible range for the estimates. This dissertation dedicates its two first chapters to providing an alternative method for estimating the income-gap (de fined to be one minus the proportion of reported to actual income) for two populations: the self-employed and the employees. The underlying data used for both cases is publicly available survey data on expenditures and income that is generated on a timely manner. This carries substantial advantages. First, relying on a general purpose survey dataset means that the estimation can be updated more frequently than if it was to rely solely on either the timing of administrative data or on survey data that is speci fically targeted to measure non-compliance. Second, it provides an alternative estimation using an independent source of data which allows for the triangulation of the estimate obtained using administrative sources. Third, it allows tax administrations which do not have readily available administrative data to perform estimations using a type of survey widespread available in most countries. The third chapter of this thesis explores the role of the extrinsic and intrinsic incentives in explaining engagement in the hidden economy defined as undeclared work practices. This chapter contributes firstly to the literature on shadow economy and to the debate of whether crowding effects are found between extrinsic and intrinsic motivations in a tax environment.
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The Vascular Flora of Steele Creek Park and a Quantitative Study of Vegetation Patterns in Canopy Gaps, Sullivan County, TennesseeKlahs, Phillip C 01 December 2014 (has links)
An inventory of vascular plants was conducted in Steele Creek Park in Sullivan County, Tennessee from March 2013 to September 2014. The park covers an area of 892 ha and lies within the Ridge and Valley Province. The inventory of vascular plants documented 547 species of 323 genera and 101 families. Two hundred sixteen taxa were newly reported for Sullivan County. Tennessee Special Concern Species included Cardamine rotundifolia, Castanea dentata, Lonicera dioica, Allium tricoccum, Cypripedium acaule, and Panax quinquefolius. A single species, Juglans cinerea L., is considered a Tennessee Threatened Species. Vegetation patterns were studied quantitatively by installing 10 study plots within forest canopy gaps and a comparable set of 10 in areas with intact canopy. Plots within a canopy gap recorded more vascular plant diversity when compared to plots of intact canopy when unshared species were considered. Steele Creek Park provides a botanically rich area for future studies.
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Comparing trend and gap statistics across tests: distributional change using ordinal methods and bayesian inferenceDenbleyker, John Nickolas 01 May 2012 (has links)
The shortcomings of the proportion above cut (PAC) statistic used so prominently in the educational landscape renders it a very problematic measure for making correct inferences with student test data. The limitations of PAC-based statistics are more pronounced with cross-test comparisons due to their dependency on cut-score locations. A better alternative is using mean-based statistics that can translate to parametric effect-size measures. However, these statistics as well can be problematic. When Gaussian assumptions are not met, reasonable transformations of a score scale produce non-monotonic outcomes.
The present study develops a distribution-wide approach to summarize trend, gap, and gap trend (TGGT) measures. This approach counters the limitations of PAC-based measures and mean-based statistics in addition to addressing TGGT-related statistics in a manner more closely tied to both the data and questions regarding student achievement. This distribution-wide approach encompasses visual graphics such as percentile trend displays and probability-probability plots fashioned after Receiver Operating Characteristic (ROC) curve methodology. The latter is framed as the P-P plot framework that was proposed by Ho (2008) as a way to examine trends and gaps with more consideration given to questions of scale and policy decisions. The extension in this study involves three main components: (1) incorporating Bayesian inference, (2) using a multivariate structure for longitudinal data, and (3) accounting for measurement error at the individual level. The analysis is based on mathematical assessment data comprising Grade 3 to Grade 7 from a large Midwestern school district. Findings suggest that PP-based effect sizes provide a useful framework to measure aggregate test score change and achievement gaps. The distribution-wide perspective adds insight by examining both visually and numerically how trends and gaps are affected throughout the score distribution. Two notable findings using the PP-based effect sizes were (1) achievement gaps were very similar between the Focal and Audit test, and (2) trend measures were significantly larger for the Audit test. Additionally, measurement error corrections using the multivariate Bayesian CTT approach had effect sizes disattenuated from those based on observed scores. Also, the ordinal-based effect size statistics were generally larger than their parametric-based counterparts, and this disattenuation was practically equivalent to that seen by accounting for measurement error. Finally, the rank-based estimator of P(X>Y) via estimated true scores had smaller standard errors than for its parametric-based counterpart.
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Bhutanese Refugee Students: Their Perceptions Of High School And Challenges Of Accessing A Four-Year College Degree In The U.s.Ghising, Hemant Tamang 01 January 2019 (has links)
The recent trend of refugee resettlement in the U.S. has presumably shifted to a new and more hopeful life for refugees. However, refugees experience another phase of challenges once they resettle in the U.S. Their transition from a life of statelessness to that of the citizen in a developed country is a painful experience, yet life has improved economically, especially after years of living in poverty in a refugee camp. The fact that Bhutanese refugee parents choose to resettle in the U.S. is primarily motivated by their hopes for a better education for their children. The following qualitative research study strives to understand both the opportunity gaps and the challenges that Bhutanese refugee students experience. This study also helps to shift the narrative from the student being the problem to the school systems in place that maintains or ameliorate the gaps in opportunities for refugee students in higher education.
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Examining Lifestyle Behaviours and Weight Status of Primary Schoolchildren: Using Mozambique to Explore the Data Gaps in Low- and Middle-Income CountriesManyanga, Taru 11 October 2019 (has links)
The emergency of malnutrition, in all of its forms, and physical inactivity among children and adolescents as serious public health challenges, especially in resource-limited low- and middle-income countries is concerning and requires attention. Data on the prevalence of unhealthy weight status and levels of physical inactivity among children and adolescents in these low- and middle-income countries are limited, not systematically collected nor are they well documented. Accurate prevalence estimates, and an informed understanding of the relationships among movement behaviours and weight status of children and adolescents, are required to facilitate evidence-informed interventions and public health policies in these countries.
The main purposes of this dissertation were to examine relationships between lifestyle behaviours and weight status among primary schoolchildren in Mozambique; compare body mass indices and movement behaviours of Mozambican schoolchildren to those of children from other countries; and use these findings to highlight important data gaps that exist in low- and middle-income countries. First, the Active Healthy Kids Global Alliance’s Report Card development methodology was used to conduct thorough narrative literature searches, identify data gaps and research needs which subsequently informed research questions and primary data collection. A published protocol that was developed for the multinational cross-sectional International Study of Childhood Obesity, Lifestyle and the Environment was adopted and used for primary data collection among urban and rural schoolchildren in Mozambique (n=683), to facilitate data comparability. Anthropometric (weight, height, percent body fat, bioelectric impedance, mid-upper-arm circumference, waist-circumference) and accelerometry (nocturnal sleep, sedentary time, various intensities of physical activity) data were objectively measured by trained personnel. Data about lifestyle behaviours (diet and movement behaviours), demographics and environmental (home, neighbourhood, school) factors associated with child weight status were collected using context-adapted questionnaires. As part of this dissertation, six manuscripts were developed and submitted for publication in peer-reviewed scientific journals.
Overall, the narrative literature searches revealed a dearth of information about prevalences of unhealthy weight status, and key lifestyle behaviours among children and adolescents in low- and middle-income countries. Results from data collected in Mozambique showed overweight/obesity to be an emerging public health concern, especially among urban children (11.4%), while thinness still persists and is more prevalent among rural schoolchildren (6.3%). Moderate- to vigorous-intensity physical activity, active transport and mother’s body mass index were found to be important modifiable correlates of weight status for Mozambican children. Distinct differences in the prevalences and correlates of lifestyle behaviours (sleep and physical activity) were observed between urban and rural children in Mozambique. The findings showed that mean moderate- to vigorous-intensity physical activity was lower (82.9±29.5 minutes/day) among urban compared to rural Mozambican children (96.7±31.8 minutes/day). Compared to children from 12 other countries, on average, children from Mozambique had lower body mass indices, higher daily moderate- to vigorous-intensity physical activity, lower daily sedentary time and comparable sleep duration. For example, rural Mozambican children had lower mean BMI z-scores (-0.5±0.9) than the rest of the sample (0.4±1.3), 46 more minutes of daily moderate- to vigorous-intensity physical activity, and 99 less minutes of daily sedentary time than the other children. Furthermore, linear distributions of study site-specific body mass index (positive), minutes of daily moderate- to vigorous-intensity physical activity (negative), and daily sedentary time (positive) by country human development index were observed. Compared to others, children from the urban Mozambican site closely resembled those from Nairobi Kenya on body mass index and movement behaviours, whereas those from rural Mozambique were distinctly different from the rest of the sample on many indicators.
Findings from this dissertation highlight the importance of including participants from low, medium, high, and very high-income countries in multinational studies investigating contextual and environmental factors related to childhood weight status. The findings revealed important differences between urban and rural children supporting the need to include both in study samples and especially in low- and middle-income countries where the majority of people live in rural areas. Finally, findings from this dissertation have demonstrated that despite the reported global progress in the availability of data about obesity and related factors among children and adolescents, gaps still exist and need to be filled in low- and middle-income countries.
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Advertising Message and Customer Satisfaction : A Case of LIDL SwedenIftikhar, Ahmed, Yusi, Zhao January 2008 (has links)
<p>Title: Advertising message and Customer Satisfaction A case of Lidl Sweden</p><p>Problem: “Are the customers satisfied when they compare marketing message with services provided by Lidl grocery store?”</p><p>Purpose: We aim to analyze the satisfaction level of customers at Lidl store and how</p><p>effective messages delivered in the advertisement.</p><p>Method: We used a primary research through the interviews of the managers in Lidl, and</p><p>a survey questionnaire by the customers. We also used the secondary data from</p><p>the website of Lidl and some qualitative information from textbooks and</p><p>different sources.</p><p>Conclusion: After the research, we conclude that the advertising messages of Lidl is clear</p><p>and most of the customers feel satisfied with price and the quality of Lidl’s</p><p>products. However, about the non-food products, the customers do not feel so</p><p>pleasant and they do not have much knowledge about after sale services.</p>
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Implementation of the University of Missouri Terawatt Test Stand and the study of a large, multichanneling, laser tirggered gas switchLeChien, Keith Robert, January 2006 (has links)
Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 27, 2007) Vita. Includes bibliographical references.
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