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  • 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.
41

Responses of Diaptomus spp. from an oligotrophic lake to variations in food quality

Butler, Nancy M. January 1990 (has links)
Copepods live in a nutritionally dilute environment, experiencing temporal and spatial variations in food supply which differ in magnitude and predictability. Understanding the mechanisms by which organisms deal with changes in their food is a primary concern in elucidating the nutritional ecology of zooplankton and the role of food in structuring zooplankton communities. In this thesis, I examine changes in behavior, morphology, and physiology of two species of calanoid copepods (Diaptomus kenai and D. leptopus) in response to variation in food composition and density. In Chapter Two, I present a study of population-level responses to variation in food composition and quality, using fertilization techniques to generate a range of phytoplankton communities in field enclosures. The phytoplankton assemblages studied supported copepod populations which differed in such attributes as population size, reproduction, and body size. The most striking finding of this study was the occurrence of two co-existing size classes of D. kenai, the abundance and clutch size of which varied among the enclosures, suggesting differences between the two classes in their ability to utilize the different phytoplankton communities. Chapter Three investigates patterns of lipid storage in response to changes in food supply. I concluded that lipid stores were affected by species composition of the phytoplankton food and the two copepod species differed in their sensitivity to differences in cell chemistry. Chapter Four investigates behavioral responses of the two size classes of D. kenai to changes in food composition and abundance. Subtle differences in feeding behavior suggest that the two sizes differ in their utilization of available food. These results demonstrate that D. kenai and D. leptopus are capable of responding to changes in their food supply through modifications of their behavior, morphology, and physiology over a range of magnitudes and time scales. There can be very subtle changes in feeding behavior or very pronounced changes in size structure. Responses occur over time scales ranging from hours to days to seasons. These results also bring into question the utility of models generated under laboratory conditions in predicting behaviors or dynamics of copepod populations and communities in nature. / Science, Faculty of / Zoology, Department of / Graduate
42

Kuwaiti Mothers’ Food Parenting Styles, Practices, and Food-Environments in the Context of Living With or Without Extended Family - A Mixed Methods Study

Alawadhi, Noor January 2020 (has links)
Background and Objectives: Childhood obesity and its comorbidities are an emerging health problem among the Kuwaiti population and their neighboring countries. The food environment and parental role are among the key determinates of eating behavior in children. Parents influence their children's eating through both their food parenting styles (FPS) during meal and snack times, and their goal-directed food parenting practices (FPP). The majority of studies have examined nuclear families; however, with the increased cost of daily living and women in the workforce, many mothers are feeding their children in multigenerational or extended family households. This study aimed to examine the prevalence of FPS and FPP among Kuwaiti mothers with school-age children and the demographic variables associated with them; and to further explore the mothers' benefits, challenges, and strategies of child feeding between those who live with their in-laws, those who live independently, and during Zwara the weekly family gatherings. Methods: Using a sequential explanatory design, this mixed-methods study consisted of two distinct phases. Phase 1 (quantitative): 1625 Kuwaiti mothers with children aged 6 to 12 years completed a cross-sectional electronic survey including the Caregiver Feeding Styles Questionnaire (CFSQ), five constructs from the Comprehensive Feeding Practices Questionnaire (CFPQ) and a range of socioeconomic and living situations. Phase 2 (qualitative): 32 mothers took part in a follow-up in-person semi-structured interview about benefits, challenges, and strategies of child feeding within two groups - 16 living with in-laws, and 16 living independently; each group consisted of equal numbers of Authoritative and Indulgent feeding styles. Conclusion: Phase 1: The mother's perception of child weight was the only factor associated with both FPSs and FPPs, indicating that it as a key influential factor. The mother's education level and childbirth order were associated with FPPs, implying their direct influence on specific goal-directed practices of child-eating. Whereas, living arrangements, number of hired help, living district, and child age were associated with FPSs, suggesting their indirect influence on the parent-child interaction. Phase 2: The benefits, challenges, and strategies of child feeding differed between the living arrangements, and the Indulgent and Authoritative feeding styles differed only by the strategies used. Also, the Kuwaiti mothers were more prone to follow the Indulgent style during the weekend gatherings, despite being more likely to use the Authoritative style during the weekday. Likewise, Kuwaiti Grandparents were perceived to have Indulgent feeding styles tendencies with Grandchild, which has been linked with higher child weight in other studies. These differences in usage of FPPs and FPSs in different settings suggest that there is a need to develop and implement nutrition interventions to improve maternal feeding practices based on their household arrangements.
43

Níveis de sombreamento sobre a produtividade e valor nutritivo do capim-xaraés (Urochloa brizantha cv. Xaraés)

Leal, Natalia Santos, 1987. January 2017 (has links)
Orientador: Mario de Beni Arrigoni / Coorientador: Paulo Roberto de Lima Meirelles / Resumo: Em razão da excelente adaptação das plantas do gênero Urochloa aos ecossistemas brasileiros, a utilização de sombreamento artificial em estudos com avaliação de valor nutritivo se torna uma ferramenta importante para se conhecer o comportamento e a qualidade das plantas quando utilizadas em integrações com componentes arbóreos. O experimento foi conduzido na FMVZ - UNESP Botucatu, com objetivo de avaliar o valor nutritivo e a força de cisalhamento da cultivar de Urochloa brizantha (syn Brachiaria brizantha) cv Xaraés submetida a três intensidades luminosas e quatro cortes. O delineamento experimental foi em blocos completos ao acaso, sendo os tratamentos: luminosidade natural, redução de 30% e 60% de luz, com três repetições e quatro cortes. Foi realizada a composição bromatologica, a digestibilidade e a força de cisalhamento. Não houve diferença na digestibiliade entre os tratamentos em nenhum dos cortes, mas a qualidade forrageira foi influenciada pelos níveis de intensidade de luz, sendo que o tratamento com 60% de redução de luminosidade produziu forragem com maiores concentrações de proteína bruta e cinzas, menores teores de fibra de detergente neutro, hemicelulose, celulose e força de cisalhamento. Em relação aos cortes estudados, o primeiro teve o menor intervalo de corte e produziu forragem com qualidade superior em comparação ao último, pois obteve menor teores de fibra de detergente ácido, lignina, hemicelulose, celulose e consequente menor força de cisalhamento. Po... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In reason of the excellent adaptation of the plants of the genus Urochloa to the Brazilian ecosystems, the use of artificial tests in studies with evaluation of nutritive value, the use of artificial tests in studies with evaluation of nutritive value becomes an important tool to know the function and quality of plants when in integrations with tree components. The experiment was conducted at FMVZ - UNESP Botucatu, with the objective of evaluating the nutritive value and the shear force of the cultivar Urochloa brizantha (syn Brachiaria brizantha) cv Xaraes submitted to three luminous intensities and four cuts. The experimental design was in complete blocks at random, being the treatments: natural luminosity, reduction of 30% and 60% of light, with three repetitions and four cuts. It was made the bromatological composition, the digestibility and the shear force. No there was difference in digestibiliade between... (Complete abstract click electronic access below) / Doutor
44

Polarographic trace analysis of copper, lead and cadmium

Jepson, Donald Paul 01 January 1973 (has links)
The area of study for this project was the development of an accurate, reliable, and inexpensive method of trace analysis for copper, cadmium, and lead in foods. AT this time, the Association of Official Analytical Chemists Manual, eleventh edition, (4) has only official and recognized methods of analysis for copper (25.023), cadmium (25.018), and lead (25.041). In general, these procedures are long and tedious. The digestions involved often require many hours and are quite dangerous due to leakage of metallic and organometallic fumes from the digestion apparatus. The official methods of analysis for these elements require a very large outlay of money for special equipment and reagents. It was the purpose of this project to determine the following: (A) The feasibility of using polarographic detection for copper, cadmium, and lead in trace amounts.; (B) Fina da new method of sample decomposition to replace the present digestion methods.; (C) Study the selection media prior to polarographic detection.; (D) Develop a method of simultaneous polarographic detection of copper, cadmium, and lead.
45

Quantitative aqueous ammonium ion analysis by transmission infrared spectroscopy

Grunfeld, Eva January 1987 (has links)
No description available.
46

A Multicomponent Evaluation of Food Properties Affecting Rumination in an Adult with Intellectual Disabilities

Sanchez, Aaron Joseph 07 1900 (has links)
Rumination consists of voluntary regurgitation of partially digested food, followed by chewing and re-swallowing or expulsion of regurgitated stomach contents (DM-ID2). Little research has systematically analyzed the differential effects of type or quantity of food on rumination across extended observations. This analysis demonstrated that certain (isolated) foods may differentially affect the rate of rumination. Furthermore, patterns of responding and manipulations of quantity may provide evidence for naturally occurring contingencies of punishment for the rumination of particular foods. These results may provide an avenue for minimally invasive, sustainable treatment for individuals with severe and chronic rumination.
47

Comprehensive two-dimensional liquid chromatographic analysis of anthocyanins

Willemse, Chandre Monique 04 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Anthocyanins are naturally occurring pigments responsible for the colour of many natural products, including grapes and wine. These pigments are important to the food industry and have been recognised for their nutritional value since they play an important role in the reduced risk of various chronic diseases in humans. Anthocyanins also play an important role in the aesthetic perception and quality of red wine. However, due to the large structural diversity of grape-derived anthocyanins and the many derivatives formed from these during wine ageing, the accurate analysis of wine pigments is extremely challenging. Reversed-phase liquid chromatography (RP-LC) is mostly used for anthocyanin analysis, although the technique often provides insufficient resolving power for complex mixtures of anthocyanins. In addition, the lack of commercially available standards and identical mass spectral characteristics hampers identification of these compounds. The coupling of multiple orthogonal separation systems in comprehensive 2-dimensional liquid chromatography (LC×LC) offers a more powerful approach for the separation of complex mixtures. The current work therefore focussed on exploring the potential of LC×LC for the improved analysis of anthocyanins and derived pigments in natural products and wine. The first part of this work focussed on developing a hydrophilic interaction chromatography (HILIC) method as an alternative to RP-LC for the anthocyanin analysis. Following extensive optimisation, the method proved suitable for the analysis of a diverse range of anthocyanins in natural products. Significantly, it also showed alternative selectivity compared to RP-LC. The optimised HILIC method was then used in combination with RP-LC to develop an off-line LC×LC approach for anthocyanins. For this purpose, half-minute fractions of the HILIC effluent were collected and reinjected onto a RP-LC column. The off-line HILIC×RP-LC method demonstrated exceptionally high resolving power, as measured in terms of the practical peak capacity, with many compounds separated in two dimensions that co-eluted in 1-dimensional HPLC. Interestingly, group-type separation was also observed based on the degree and/or nature of glycosylation and acylation of anthocyanins. In the final part of the work, a systematic approach was used for the development and optimisation of and on-line HILIC×RP-LC method by using a 10-port switching valve to automatically transfer fractions between the two columns. This method was then coupled to high resolution mass spectrometry (MS) to allow the detailed investigation of anthocyanins and derived products in wine. Ninety four pigments were identified in one- and six-year old Pinotage wines based on HILIC×RPLC separation in combination with accurate mass MS data and fragmentation information. Significant differences in especially the content of derived pigments were observed between the wines. In summary, the methods developed in this work provide the means to improve anthocyanin analysis, and therefore also show promise for the detailed investigation of these important compounds and their alteration in natural products and their derived commodities. / AFRIKAANSE OPSOMMING: Antosianiene is natuurlike pigmente wat verantwoordelik is vir die kleur van baie natuurlike produkte, insluitende dié van druiwe en wyn. Hierdie pigmente is belangrik vir die voedsel industrie en word gereken vir hul voedingswaarde aangesien hulle 'n belangrike rol speel in die verlaagde risiko van verskeie chroniese siektes onder die mens. Antosianiene speel ook 'n belangrike rol in die estetiese persepsie en kwaliteit van rooiwyn. Desnieteenstaande, as gevolg van die groot strukturele diversiteit van druifgeproduseerde antosianiene en die vele chemiese afgeleides wat uit hulle gevorm kan word tydens wyn bereiding en veroudering, is die akkurate analise van natuurlike wyn-pigmente uiters uitdagend. Omgekeerde-fase vloeistofchromatografie (RP-LC) word meestal gebruik vir die analise van antosianiene. Dié tegniek bied egter dikwels onvoldoende skeidingsvermoë vir komplekse mengsels van antosianiene en verwante molekules. Verder belemmer die onbeskikbaarheid van kommersiële standaarde en identiese massa spektrale eienskappe die identifikasie van hierdie verbindings. Die kombinasie van verskillende ortogonale skeidings meganismes in omvattende 2- dimensionele vloeistofchromatografie (LC×LC) bied egter 'n baie kragtiger benadering vir die skeiding van komplekse mengsels. Die huidige werk fokus dus op die ontginning van die potensiaal van LC×LC vir die verbeterde ontleding van antosianiene en verwante afgeleide pigmente in natuurlike produkte en wyn. Die eerste deel van hierdie werk het gefokus op die ontwikkeling van 'n hidrofiliese interaksie chromatografiese (HILIC) metode as ʼn alternatief vir RP-LC analise van antosianiene. Na uitgebreide optimisering, is gevind dat die metode geskik is vir die ontleding van 'n verskeidenheid van antosianiene in natuurlike produkte. Van groot belang is dat dit ook alternatiewe selektiwiteit in vergelyking met RP-LC demonstreer. Hierdie geoptimiseerde HILIC metode word dan voorts gebruik in kombinasie met RP-LC vir die ontwikkeling van ʼn af-lyn LC×LC benadering vir die analise van antosianiene. Hiervoor is half-minuut fraksies van die HILIC uitvloei opgevang en her-ingespuit op 'n RP-LC kolom. Dié af-lyn HILIC×RP-LC metode toon buitengewoon hoë skeidingsvermoë, gemeet in terme van die bereikbare praktiese piek kapasiteit, met baie verbindings wat geskei is in die twee dimensies wat saam elueer in 1-dimensionele HPLC. Interessant genoeg is groep-tipe skeiding ook waargeneem gebaseer op die graad en / of aard van glukosilasie en asilering van die antosianiene. In die laaste deel van die werk, is 'n sistematiese benadering gevolg vir die ontwikkeling en optimisering van ʼn aan-lyn HILIC×RP-LC deur gebruik te maak van 'n 10-poort oorskakelingsklep wat fraksies outomaties oordra tussen die twee kolomme. Die bogenoemde metode is ook verder gekoppel aan hoë resolusie massaspektrometrie (HR-MS) om ʼn gedetailleerde ondersoek van antosianiene en hulle afgeleide verbindings in wyn moontlik te maak. Vier en negentig pigmente is in een- en ses jaar oue Pinotage wyne geïdentifiseer gebaseer op HILIC×RP-LC skeiding in kombinasie met akkurate massa MS data en fragmentasie inligting. Beduidende verskille in veral die inhoud van antosianien-afgeleide pigmente is tussen die wyne waargeneem. Ter samevatting, die metodes ontwikkel in hierdie werk baan die weg om antosianien ontleding te verbeter en stel gevolglik die moontlikheid van selfs meer gedetailleerde studies van hierdie belangrike verbindings in natuurlike produkte in die vooruitsig.
48

Determination of arsenic in seaweed kelp tablets by hydride generation: inductively coupled plasma atomic emission spectroscopy (ICP- AES)

January 2004 (has links)
No abstract available. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004
49

Food Buzzwords: Understanding How Schemas of Proper Dieting Are Formed

Unknown Date (has links)
In the modern United States, the concept of food has become as much of a social phenomenon as it is a biological need. The process of eating has become highly structured into a system of communication. Food terms used to share ideas are referred to as food buzzwords, terms rife with additional meanings whose values are continuously debated, discussed, and altered. Such terminology has swayed how middle-class Americans interpret the proper status quo of food consumption and production. This thesis analyzes how middle-class Americans form their view of a proper diet based on their understanding of food buzzwords and other factors that influence their food choices. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
50

Estudo dos efeitos dos flavonóides provenientes do quiabo (Abelmoschus esculentum) em comportamentos relacionados à ansiedade em camundongos / Study of the effects of flavonoids from okra (Abe/moschus Esculentum) in anxiety-related behavior in mice

Dovichi, Selma Sanches 07 April 2009 (has links)
A ansiedade é uma enfermidade psiquiátrica que acomete milhões de pessoas no mundo todo. Dentre as substâncias que podem ser ligadas ao efeito ansiolítico de ervas medicinais, os flavonóides se destacam porque freqüentemente são detectados nestas ervas. Neste estudo procurou-se avaliar se compostos bioativos da classe dos flavonóides, presentes no quiabo (Abelmoschus esculentum), poderiam exercer atividade ansiolítica, empregando-se modelos comportamentais para análise de ansiedade em camundongos. Avaliou-se a quantidade e a qualidade dos flavonóides do quiabo, evidenciando-se que o quiabo liofilizado possui 16mg do flavonóide rutina/ 100g. Ratos mostraram-se capazes de absorver rutina, quando esta foi perfundida in situ no duodeno destes animais. Os comportamentos relacionados à ansiedade foram a avaliados no Campo Aberto, no Labirinto em Cruz Elevado e na Placa Perfurada após a ingestão de rações com diferentes concentrações de quiabo (4,5; 7 e 10%) por 7, 14 e 21 dias. Camundongos foram tratados com pentilenotetrazol, droga ansiogênica, e diazepam, droga ansiolítica, para comparar os resultados com aqueles de animais que receberam ração com quiabo. Os resultados obtidos no Campo Aberto mostraram que a suplementação dietética com quiabo aumentou o tempo de permanência na zona interna e também o número de quadros percorridos nesta região, de maneira semelhante ao diazepam, o que evidencia um efeito com perfil ansiolítico. No Labirinto, tanto o tempo de permanência, como o número de entradas nos braços abertos aumentaram em camundongos que consumiram rações suplementadas com quiabo e naqueles tratados com diazepam, corroborando os resultados obtidos no Campo Aberto. Na Placa Perfurada, o tempo de latência para o primeiro mergulho em um dos orifícios diminuiu em camundongos que se alimentaram com ração suplementada com quiabo, de modo similar ou superior ao efeito obtido pelo tratamento com diazepam e significativamente menor que o efeito produzido pelo tratamento com pentilenotetrazol. Não foram detectados flavonóides em tecidos biológicos de ratos e camundongos tratados com quiabo ou com rutina. Assim, concluiu-se que a suplementação dietética com o flavonóide rutina, proveniente do quiabo, resultou em efeito ansiolítico em camundongos, mostrando que o enriquecimento da dieta com alimentos ricos em rutina pode contribuir para a prevenção e tratamento do comportamento relacionado à ansiedade em camundongos. / Anxiety is a psychiatric disorder that affects millions of people around the world. Among the substances that may be linked to the anxiolytic effect of medicinal herbs, the flavonoids stand out because they are often found in these herbs. In the present study we sought to evaluate whether the c1ass of bioactive compounds flavonoids, present in okra (Abelmoschus esculentum), could exert anxiolytic activity, using models for behavioral analysis of anxiolytic activity in mice. We evaluate the quantity and quality of flavonoids of okra, showing that the okra lyophilisate has 16mg of flavonoid rutin/100g. Rats were shown able of absorb rutin, when it was perfused in situ in the duodenum of these animals. Behaviors related to anxiety were evaluated in the Open Field, Elevated Plus Maze and Hole Board after the intake of diets with different concentrations of okra (4.5, 7 and 10%) for 7, 14 and 21 days. Mice were treated with pentilenotetrazol, an ansiogenic drug, and diazepam, an anxiolytic drug, to compare the results with those of animals that received diet with okra. The results obtained in the Open Field showed that dietary supplementation with okra increased the permanence in the inner zone and also the number of tables covered in this region, so similar to diazepam, shows a anxiolytic profile. In the Elevated Plus Maze, the time, as the number of entries in open arms increased in mice that consumed diets supplemented with okra and those treated with diazepam, corroborating the results obtained in the Open Field. In the Hole Board, the latency time to first diving in one of the holes decreased in mice that are treated with diet supplemented with okra, so similar to or greater than the effect obtained by treatment with diazepam and significantly smaller than the effect produced by treatment with pentilenotetrazol. Flavonoids were not detected in biological tissues of rats and mice treated with okra or with rutin. Thus, it was concluded that dietary treatment with the flavonoid rutin, from okra, resulted in anxiolytic effect in mice, showing that the enrichment of the diet with foods rich in rutin can contribute to the prevention and treatment of anxiety-related behavior in mice.

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