• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 37
  • 17
  • 9
  • 5
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 85
  • 32
  • 11
  • 11
  • 10
  • 9
  • 9
  • 9
  • 8
  • 8
  • 8
  • 8
  • 7
  • 7
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Micotoxinas em gr?os de trigo: ocorr?ncia, efeitos da ozoniza??o e determina??o de uma forma modificada do desoxinivalenol / Mycotoxins in wheat grains: Occurrence, effects of ozonation and determination of a modified form of deoxynivalenol

Trombete, Felipe Machado 18 March 2016 (has links)
Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-01-04T11:32:19Z No. of bitstreams: 1 2016 - Felipe Machado Trombete.pdf: 1613295 bytes, checksum: 957f0b025def400e446f7c3176c76b4c (MD5) / Made available in DSpace on 2017-01-04T11:32:19Z (GMT). No. of bitstreams: 1 2016 - Felipe Machado Trombete.pdf: 1613295 bytes, checksum: 957f0b025def400e446f7c3176c76b4c (MD5) Previous issue date: 2016-03-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Mycotoxins are natural contaminants produced by filamentous fungi and they are widely present in food. In wheat grains, the presence of trichothecenes produced by Fusarium spp. and also aflatoxins, produced by Aspergillus spp. are a serious public health problem because they are toxic metabolites to man and animals that remain stable during the industrial processes to which wheat is subjected when manufacturing derived products. One way to reduce such contaminants is to use ozone (O3) in food processing. Due to its high potential as an oxidant, O3 may react with mycotoxins and reduce their toxicity due to molecular degradation. This research aimed to evaluate the effects of different conditions of ozonation on the i) reduction in mycotoxins levels (deoxynivalenol and total aflatoxins); ii): reduction in total fungal count; iii) the effects on chemical, mineral and technological profiles and; iv) the possible differences sensorial profile of the flour obtained from the ozonized grains. In a second phase of this project, a methodology for determination of D3G (deoxynivalenol-3-glucoside), a masked form of DON, using High Performance Liquid Chromatography with photodiode array detector (HPLC-PDA) was optimized and in-house validated. Results obtained from ozonation study showed that O3 reduced total fungal count in approximately 3.0 cycles log CFU/g of wheat grain and deoxynivalenol and total aflatoxins contamination up to 64.3% and 48.0%, respectively. The gaseous ozonation can be applied without negatively changing the chemical, technological and sensory characteristics of the grains and can be considered an excellent method for remediation of fungal and mycotoxin contaminations. Also, the method optimized and in-house validated for determination of D3G by HPLC-PDA showed adequate results and, it could be considered an alternative to mass spectrometry determination of D3G in wheat grains. / Micotoxinas s?o contaminantes naturais, produzidos por fungos filamentosos e, podem ocorrer em altos n?veis nos alimentos. Nos gr?os de trigo, a presen?a de tricotecenos, um grupo de micotoxinas produzidas por Fusarium spp. e, aflatoxinas, produzidas por Aspergillus spp., representam um importante problema de sa?de p?blica por serem t?xicas ao homem e animais e muito est?veis aos processos no qual o trigo ? submetido para obten??o de produtos industrializados. Uma forma de reduzir a contamina??o dos alimentos por micotoxinas ? atrav?s do uso do oz?nio (O3) no processamento do alimento. Devido ao alto potencial oxidante do O3, esse pode degradar as mol?culas das micotoxinas, tendo como consequ?ncia a elimina??o ou redu??o de seus efeitos t?xicos. Essa pesquisa teve como objetivos principais avaliar os efeitos de diferentes condi??es de ozoniza??o na i) redu??o de micotoxinas (desoxinivalenol e aflatoxinas) em gr?os de trigo; ii) redu??o nos n?veis de fungos filamentosos; iii) influ?ncia nos par?metros qu?micos, perfil de minerais e par?metros tecnol?gico dos gr?os e da farinha obtida ap?s o processamento e; iv) influ?ncia nas caracter?sticas sensoriais da farinha elaborada a partir dos gr?os ozonizados. Em uma segunda etapa do projeto, um m?todo para determina??o de uma forma modificada do desoxinivalenol (DON), o desoxinivalenol-3-glicos?deo (D3G) foi otimizada e validada intralaboratorialmente, utilizando cromatografia l?quida de alta efici?ncia com detector de arranjo de diodos (CLAE-DAD). Os resultados obtidos dos ensaios de ozoniza??o demonstraram que o O3, nas condi??es experimentais utilizadas, reduziu a contagem de fungos totais em cerca 3,0 logs UFC/g de gr?os e a contamina??o por desoxinivalenol e aflatoxinas totais em at? 64,3 % e 48,0 %, respectivamente. O processo de ozoniza??o n?o influenciou de modo negativo a qualidade qu?mica, tecnol?gica e sensorial dos gr?os de trigo, podendo ser utilizado como um excelente m?todo para remedia??o da contamina??o dos gr?os por fungos e micotoxinas. Resultados adequados tamb?m foram obtidos na valida??o do m?todo de determina??o de D3G por CLAE-DAD, demonstrando que o m?todo ? confi?vel para a determina??o dessa forma mascarada do DON em gr?os e trigo e, pode ser utilizado como um m?todo alternativo a espectrometria de massas para tal an?lise.
62

The evaluation of the group differences and item bias of the English version of a standardised test of academic language proficiency for use across English and Xhosa first-language speakers

Genevieve Ruth Haupt January 2010 (has links)
<p>South Africa&rsquo / s Language-in-Education Policy is one of additive multilingualism, but in reality this policy is not adhered to, in that most black children are being educated through the medium of English from Grade 4. This type of instruction affects the development of academic language proficiency in their primary language, as these children are not engaging in cognitively demanding tasks in their primary or first language. The Woodcock Mu&ntilde / oz Language Survey (WMLS) is a test to assess academic language proficiency in Additive Bilingual Education, and is extensively used in the United States of America (USA) for this purpose. It is important to note that the proposed study is a sub-study of a larger study, in which the original WMLS (American-English version) was adapted into English and Xhosa, to be used in South Africa to assess additive bilingual programmes. For this sub-study, the researcher was interested in examining the overall equivalence of the adapted English version of the WMLS. Owing to insufficient tests evaluating academic language proficiency in the South African context, the significance, as well as the overall aim, of the study is to ensure that the issues of group difference and item bias have been assessed to ensure that the adapted English version of the WMLS is suitable to be used across English first-language and Xhosa first-language speakers. Because this is a sub-study, the researcher (of the sub-study) has conducted an exploratory quantitative study with the use of Secondary Data. The researcher has used the framework of equivalence as a theoretical framework in order to examine the research question. Given the use of existing data, the procedures of the collection of the data by the researcher of the larger study have been outlined in the Methodology section of the present study. The sample consisted of 198 English and 197 Xhosa first-language speakers...</p>
63

The evaluation of the group differences and item bias of the English version of a standardised test of academic language proficiency for use across English and Xhosa first-language speakers

Genevieve Ruth Haupt January 2010 (has links)
<p>South Africa&rsquo / s Language-in-Education Policy is one of additive multilingualism, but in reality this policy is not adhered to, in that most black children are being educated through the medium of English from Grade 4. This type of instruction affects the development of academic language proficiency in their primary language, as these children are not engaging in cognitively demanding tasks in their primary or first language. The Woodcock Mu&ntilde / oz Language Survey (WMLS) is a test to assess academic language proficiency in Additive Bilingual Education, and is extensively used in the United States of America (USA) for this purpose. It is important to note that the proposed study is a sub-study of a larger study, in which the original WMLS (American-English version) was adapted into English and Xhosa, to be used in South Africa to assess additive bilingual programmes. For this sub-study, the researcher was interested in examining the overall equivalence of the adapted English version of the WMLS. Owing to insufficient tests evaluating academic language proficiency in the South African context, the significance, as well as the overall aim, of the study is to ensure that the issues of group difference and item bias have been assessed to ensure that the adapted English version of the WMLS is suitable to be used across English first-language and Xhosa first-language speakers. Because this is a sub-study, the researcher (of the sub-study) has conducted an exploratory quantitative study with the use of Secondary Data. The researcher has used the framework of equivalence as a theoretical framework in order to examine the research question. Given the use of existing data, the procedures of the collection of the data by the researcher of the larger study have been outlined in the Methodology section of the present study. The sample consisted of 198 English and 197 Xhosa first-language speakers...</p>
64

Modelagem estoc?stica do ?ndice de radia??o ultravioleta na costa leste do nordeste do Brasil

Lopo, Alexandre Boleira 26 March 2014 (has links)
Made available in DSpace on 2014-12-17T14:12:03Z (GMT). No. of bitstreams: 1 AlexandreBL_TESE.pdf: 4327655 bytes, checksum: 57b0b9f8e05c550b153e77bf0aa25eff (MD5) Previous issue date: 2014-03-26 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The increase in ultraviolet radiation (UV) at surface, the high incidence of non-melanoma skin cancer (NMSC) in coast of Northeast of Brazil (NEB) and reduction of total ozone were the motivation for the present study. The overall objective was to identify and understand the variability of UV or Index Ultraviolet Radiation (UV Index) in the capitals of the east coast of the NEB and adjust stochastic models to time series of UV index aiming make predictions (interpolations) and forecasts / projections (extrapolations) followed by trend analysis. The methodology consisted of applying multivariate analysis (principal component analysis and cluster analysis), Predictive Mean Matching method for filling gaps in the data, autoregressive distributed lag (ADL) and Mann-Kendal. The modeling via the ADL consisted of parameter estimation, diagnostics, residuals analysis and evaluation of the quality of the predictions and forecasts via mean squared error and Pearson correlation coefficient. The research results indicated that the annual variability of UV in the capital of Rio Grande do Norte (Natal) has a feature in the months of September and October that consisting of a stabilization / reduction of UV index because of the greater annual concentration total ozone. The increased amount of aerosol during this period contributes in lesser intensity for this event. The increased amount of aerosol during this period contributes in lesser intensity for this event. The application of cluster analysis on the east coast of the NEB showed that this event also occurs in the capitals of Paraiba (Jo?o Pessoa) and Pernambuco (Recife). Extreme events of UV in NEB were analyzed from the city of Natal and were associated with absence of cloud cover and levels below the annual average of total ozone and did not occurring in the entire region because of the uneven spatial distribution of these variables. The ADL (4, 1) model, adjusted with data of the UV index and total ozone to period 2001-2012 made a the projection / extrapolation for the next 30 years (2013-2043) indicating in end of that period an increase to the UV index of one unit (approximately), case total ozone maintain the downward trend observed in study period / A eleva??o da radia??o ultravioleta (UV), a alta incid?ncia de c?ncer de pele n?o melanoma (CPNM) no Nordeste do Brasil (NEB) e a redu??o da coluna total de oz?nio foram os motivadores do presente estudo. O objetivo desta investiga??o ? identificar e compreender a variabilidade da UV e do ?ndice de Radia??o Ultravioleta (?ndice UV) nas capitais da costa leste do NEB e ajustar modelos estoc?sticos ?s s?ries temporais do ?ndice UV visando realizar predi??es (interpola??es) e previs?es/proje??es (extrapola??es) seguido de an?lise de tend?ncia. A metodologia consistiu da aplica??o da an?lise multivariada (an?lise de componentes principais e an?lise de agrupamentos), m?todo Predictive Mean Matching (PMM) para preenchimento de falhas nos dados, modelo autoregressivo de defasagens distribu?das ou Autoregressive Distributed Lag (ADL) e teste Mann-Kendal. A modelagem via ADL ocorreu atrav?s da estima??o de par?metros, diagn?stico, an?lise de res?duos e avalia??o da qualidade das predi??es/previs?es via erro quadr?tico m?dio e coeficiente de correla??o de Pearson. Os resultados da investiga??o indicaram que a variabilidade anual da UV na capital do Rio Grande do Norte (Natal) possui uma caracter?stica nos meses de setembro e outubro que consiste em uma estabiliza??o/redu??o do ?ndice UV em raz?o da maior concentra??o anual de oz?nio total. A maior quantidade de aeross?is neste per?odo contribui em menor intensidade para este evento. A aplica??o da an?lise de agrupamento (cluster) na costa leste do NEB mostrou que este evento tamb?m ocorre nas capitais da Para?ba (Jo?o Pessoa) e Pernambuco (Recife). Os eventos extremos da UV do NEB foram analisados a partir da cidade de Natal e estavam associados ? falta de cobertura de nuvens e n?veis abaixo da m?dia anual de oz?nio total e n?o ocorriam na totalidade da regi?o em fun??o da distribui??o espacial desigual dessas vari?veis. O modelo ADL (4, 1), ajustado com dados do ?ndice UV e oz?nio total para o per?odo de 2001 a 2012, realizou a proje??o/extrapola??o para os pr?ximos 30 anos (2013-2043) indicando ao fim deste per?odo eleva??o de aproximadamente uma unidade do ?ndice UV, caso o oz?nio total mantenha a tend?ncia de queda verificada no per?odo de estudo
65

An?lise de desempenho de um refrigerador de pequeno porte com drop in de refrigerantes hidrocarbonetos

Marques, Jo?o Carlos Borges 20 December 2010 (has links)
Made available in DSpace on 2014-12-17T14:58:09Z (GMT). No. of bitstreams: 1 JoaoCBM_DISSERT.pdf: 5805236 bytes, checksum: 65458c7bbde564338d0a049065004604 (MD5) Previous issue date: 2010-12-20 / From what was stated in the Montreal Protocol, the researchers and refrigeration industry seek substitutes for synthetic refrigerants -chlorofluorocarbons (CFCs) and HCFCs (HCFC) - that contribute to the depletion of the ozone layer. The phase-out of these substances was started using as one of the replacement alternatives the synthetic fluids based on hydro fluorocarbons (HFCs) that have zero potential depletion of the ozone layer. However, contribute to the process of global warming. HFC refrigerants are greenhouse gases and are part of the group of gases whose emissions must be reduced as the Kyoto Protocol says. The hydrocarbons (HC's), for not contribute to the depletion of the ozone layer, because they have very low global warming potential, and are found abundantly in nature, has been presented as an alternative, and therefore, are being used in new home refrigeration equipment in several countries. In Brazil, due to incipient production of domestic refrigerators using HC's, the transition refrigerants remain on the scene for some years. This dissertation deals with an experimental evaluation of the conduct of a drinking fountain designed to work with HFC (R-134a), operating with a mixture of HC's or isobutane (R-600a) without any modification to the system or the lubricating oil. In the refrigeration laboratory of Federal University of Rio Grande do Norte were installed, in a drinking fountain, temperature and pressure sensors at strategic points in the refrigeration cycle, connected to an acquisition system of computerized data, to enable the mapping and thermodynamics analysis of the device operating with R-134a or with a mixture of HC's or with R-600a. The refrigerator-test operating with the natural fluids (mixture of HC's or R-600a) had a coefficient of performance (COP) lower than the R-134a / A partir do estabelecido no Protocolo de Montreal, os pesquisadores e a ind?stria de refrigera??o buscam substitutos para os refrigerantes sint?ticos clorofluorcarbonos (CFC s) e os hidroclorofluorcabonos (HCFC s), que contribuem para a degrada??o da camada de oz?nio. O phase- out dessas subst?ncias foi iniciado utilizando como uma das alternativas de substitui??o os fluidos sint?ticos baseados em hidrofluorcarbonos (HFC s) que possuem potencial nulo de deple??o da camada de oz?nio, entretanto, contribuem para o processo de aquecimento global. Os refrigerantes HCF s s?o gases de efeito estufa e fazem parte do grupo de gases cujas emiss?es devem ser reduzidas, conforme Protocolo de Kyoto. Os hidrocarbonetos (HC s), por n?o contribu?rem para a degrada??o da camada de oz?nio, por terem muito baixo potencial de aquecimento global, e por serem encontrados abundantemente na natureza, t?m sido apresentados como alternativa e, por isso, est?o sendo usados em novos equipamentos de refrigera??o dom?stica em diversos pa?ses. No Brasil, devido ? produ??o incipiente de refrigeradores dom?sticos utilizando HC s, os refrigerantes de transi??o continuar?o em cena por mais alguns anos. Este trabalho trata de uma avalia??o experimental do comportamento de um bebedouro projetado para trabalhar com HFC (R-134a), operando com uma mistura de HC s ou isobutano (R-600a) sem nenhuma modifica??o no sistema ou no ?leo lubrificante. No laborat?rio de refrigera??o da Universidade Federal do Rio Grande do Norte foram instalados, em um bebedouro, sensores de press?o e temperatura em pontos estrat?gicos do ciclo de refrigera??o, conectados a um sistema de aquisi??o de dados computadorizado, de modo a permitir o mapeamento e a an?lise termodin?mica do dispositivo operando com R-134a ou com a mistura HC s ou com R-600a. O refrigerador de testes, operando com fluidos naturais (mistura de HC s ou R-600a), apresentam um coeficiente de performance (COP) inferior ao do R-134a
66

Adaptiva talbaserade system i fordon : Designförslag för att främja user experience

Holdaj Petersson, Kalle, Thunberg, Martin January 2013 (has links)
Denna kandidatuppsats undersöker hur user experience kan främjas i ett adaptivt talbaserat system i en fordonskontext. Att undersöka och involvera user experiencei adaptiva talbaserade system är i synnerhet viktigt i denna kontext då den primära sysslan, att köra, bör störas så lite som möjligt. Ett adaptivt system ger möjlighet att effektivisera interaktion och ett talbaserat system låter föraren fokusera på trafiken.Genom att undersöka existerande teori och utföra empiriska undersökningar i form av användartester genom Wizard of Oz-tekniken och intervjuer har vi skapat designoch dialogexempel. Dessa förslag kan främja user experience och på så vis bidra till att den interaktion som sker är effektiv och behaglig. / This bachelor thesis aims to build an understanding how user experience can be promoted in an adaptive speech-based system, which is found in the context of an automobile. Investigating this particular context and system is of importance since the primary task is to drive safely and let the driver focus on driving rather than system. An adaptive system provides the opportunity to make the interaction more effective and a speech-based system lets the driver focus on the traffic environment. By studying relevant theory and by carrying out user tests, with the technique Wizard of Oz, we have drafted design and dialogue recommendations. These recommendations can promote user experience and make the interaction of the system more effective and pleasant. / Safe Speech for Knowledge (SSK)
67

Persuasive Chatbot Conversations : Towards a Personalized User Experience

Rönnberg, Sofia January 2020 (has links)
Helping drivers improve their driving skills and become safer drivers is a problematic topic. Most drivers have a lacking self-assessment ability and consider themselves above average driving skills. This is believed to be related to the lack of continuous feedback after getting the driver’s license. This has led to initiatives to find alternative ways of coaching drivers toward better self-assessment and thereby toward safer driving. Chatbots and conversational interfaces has received increasing attention over the years and could be technologies that can solve these challenges. However, a major challenge to chatbots is that they are mostly implemented in a “one-size-fits-all” approach, and while personalization of the chatbot could solve that challenge, it ishard to achieve. In this study, personalized chatbot conversations that aim to coach drivers are examined. The aim is to create a guide that can help designers and practitioners with design decisions that needs to be considered when creating coaching chatbot conversations. The study was performed as a Wizard of Oz study, where attributes for personalization as well as coaching considerations were tested with users in two iterations to iteratively develop the guide. The findings of the study include the guide itself with its guidelines (see appendix 4), as well as insights on considerations required chatbot personalization and coaching. Regarding personalization, chatbot personality and level of control were identified as two attributes that were fit for adaptation. These can lead to social benefits as well as more tailored services to the users. For coaching, the use of follow-ups, feedback and the chatbot’s attitude are identified as necessary considerations when designing coaching chatbot conversations.
68

"Sorry, what was your name again?" : How to Use a Social Robot to Simulate Alzheimer’s Disease and Exploring the Effects on its Interlocutors

Kanov, Maria January 2017 (has links)
Machines are designed to be infallible, but what happens if they are suddenly struck by chronic mental decline such as dementia? In this research, a social robot has been transformed into a mild-stage Alzheimer’s patient. The ultimate goal is to use it as a training tool for caregivers and medical students, as well as to raise general awareness for the disease. In particular, the study aimed to identify how to simulate Alzheimer’s with a social robot and what the effects are on its conversation partners. Thanks to its properties, the back-projected robotic head Furhat was the ideal candidate to adopt the role of Max. The sources of inspiration derived from interviews and observations. A Wizard of Oz setup enabled a conversation between the character and the user, who was given the task of asking about the robot’s life. To allow for in-between subject comparisons, the set of 20 participants was a mixture of medical and non- medical students, as well as people who knew someone with dementia closely and those who never met any. The experience was evaluated through pre- and post-interviews along with user observations. The results indicate that the patient simulation was convincing, leading the users to treat the machine as a human being and develop an emotional bond to it. They remained patient in spite of the robot’s symptoms, which affirms its potential for educational use. After all, this project aims to inspire researchers to find solutions in unconventional ways.
69

Towards establishing the equivalence of the IsiXhosa and English versions of the Woodcok Munoz language survey : an item and construct bias analysis of the verbal analogies scale

Roomaney, Rizwana January 2010 (has links)
<p>This study formed part of a larger project that is concerned with the adaptation of a test of cognitive academic language proficiency, the Woodcock Mu&ntilde / oz Language Survey (WMLS). The WMLS has been adapted from English into isiXhosa and the present study is located within the broader study that is concerned with establishing overall equivalence between the two language versions of the WMLS. It was primarily concerned with the Verbal Analogies (VA) scale. Previous research on this scale has demonstrated promising results, but continues to find evidence of some inequivalence. This study aimed to cross-validate previous research on the two language versions of the WMLS and improve on methodological issues by employing matched groups. It drew upon an existing dataset from the larger research project. The study employed a monolingual matched two-group design consisting of 150 mainly English speaking and 149 mainly isiXhosa learners in grades 6 and 7. This study had two sub aims. The first was to investigate item bias by identifying DIF items in the VA scale across the isiXhosa and English by conducting a logistic regression and Mantel-Haenszel procedure. Five items were identified by both techniques as DIF. The second sub aim was to evaluate construct equivalence between the isiXhosa and English versions of the WMLS on the VA scale by conducting a factor analysis on the tests after removal of DIF items. Two factors were requested during the factor analysis. The first factor displayed significant loadings across both language versions and was identified as a stable factor. This was confirmed by the Tucker&rsquo / s Phi and scatter plot. The second factor was stable for the English version but not for the isiXhosa version. The Tucker&rsquo / s phi and scatter plot indicated that this factor is not structurally equivalent across the two language versions</p>
70

Towards establishing the equivalence of the English version of the verbal analogies scale of the Woodcock Munuz Language Survey across English and Xhosa first language speakers

Ismail, Ghouwa January 2010 (has links)
<p>In the majority of the schools in South Africa (SA), learners commence education in English. This English milieu poses a considerable challenge for English second-language speakers. In an attempt to bridge the gap between English as the main medium of instruction and the nine indigenous languages of the country and assist with the implementation of mother-tongue based bilingual education, this study focuses on the cross-validation of a monolingual English test used in the assessment of multilingual or bilingual learners in the South African context. This test, namely the Woodcock Mu&ntilde / oz Language Survey (WMLS), is extensively used in the United States in Additive Bilingual Education in the country. The present study is a substudy of a broader study, in which the original WMLS (American-English version) was adapted into SA English and Xhosa. For this specific sub-study, the researcher was interested in investigating the scalar equivalence of the adapted English version of the Verbal Analogies (VA) subscale of the WMLS across English first-language speakers and Xhosa first-language speakers. This was achieved by utilising differential item functioning (DIF) and construct bias statistical techniques. The Mantel-Haenszel DIF detection method was employed to detect DIF, while construct equivalence was examined by means of exploratory factor analysis (EFA) utilising an a priori two-factor structure. The Tucker&rsquo / s phi coefficient was used to assess the congruence of the construct across the two language groups</p>

Page generated in 0.0595 seconds