• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 162
  • 94
  • 42
  • 22
  • 14
  • 10
  • 10
  • 10
  • 7
  • 6
  • 5
  • 4
  • 4
  • 4
  • 4
  • Tagged with
  • 460
  • 264
  • 104
  • 71
  • 58
  • 46
  • 44
  • 39
  • 34
  • 33
  • 32
  • 31
  • 27
  • 27
  • 26
  • 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.
331

Placing a Lens on the First 1000 Days of Life: Prenatal Intake, Infant Feeding, the Microbiome and Child Growth

Rana Chehab (11139342) 26 July 2021 (has links)
<div>The first 1000 days of life, from conception until the child’s second birthday, constitute a critical window for child growth and development. During infancy and early childhood, significant and rapid physical changes occur, including increases in weight, height, and brain size and organ development accompanied by cognitive and psychomotor development. Adequate infant feeding, including breastfeeding and complementary feeding, that meets the infants’ energy and nutrient requirements can help protect against growth faltering, infant and child morbidity and mortality, and delayed mental and motor development. Adequate nutrition during this critical period can also protect against adverse health outcomes and chronic diseases later in life according to the hypothesis of developmental origins of health and disease.</div><div><br></div><div>A web of factors that are country- and culture- specific influence infant feeding practices and child growth. Further, the microbiome has been suggested as a strong potential player in the association between infant nutrition and child growth. Therefore, the overarching theme of the current dissertation is to investigate hypotheses that can provide evidence to inform the paradigm linking socio-demographic, maternal, and child determinants including prenatal intake to infant feeding, the breast milk and infant gut microbiome, and child growth within the first 1000 days of life. Specifically, aims one and two examine the socio-demographic, maternal, and child determinants of child growth and breastfeeding in a cross-sectional survey of mother-child dyads in Lebanon, a middle-income country undergoing nutrition transition in the Middle East. The third aim focuses on the CHILD cohort study, a multi-center longitudinal prospective birth cohort study, to examine the associations between prenatal diet and supplement intake and the breast milk microbiome. Finally, the fourth aim is to review the evidence for the potential of the infant gut microbiome as a promising target linking complementary feeding to child undernutrition in low- and middle- income countries (LMIC) with the highest burden of undernutrition.</div><div><br></div><div>The results for aim one revealed sex-specific determinants of child growth in Lebanon. The determinants examined through a hierarchical conceptual framework included: maternal and paternal education among boys and crowding index among girls at the distal sociodemographic level, and maternal obesity among girls at the intermediate maternal level. The proximal child determinants included birth length, number of children in the household and breastfeeding duration among girls, birthweight among boys and child’s age among boys and girls.</div><div><br></div><div>In the analysis for aim two, breastfeeding practices were suboptimal in Lebanon as less than half (41.5%) of the infants were exclusively breastfed during the 40-day rest period and 12.3% were exclusively breastfed during the 6-month duration recommended by the World Health Organization. Higher socioeconomic status, as reflected by a larger number of cars owned, and C-section delivery were consistently inversely associated with lower odds of exclusive breastfeeding for 40 days and 6 months. Belonging to a family with more children was associated with higher odds of exclusive breastfeeding for 40 days; while maternal overweight and obesity were associated with lower odds of exclusive breastfeeding for 6 months.</div><div><br></div><div>Findings from aim three suggested that prenatal supplement use, but not prenatal dietary quality and patterns, modulate the breast milk microbiota composition in the CHILD cohort in Canada. This project was exploratory and utilized one of the largest birth cohort studies with available breast milk microbiome data. Specifically, use of vitamin C and D supplements plus multivitamins during any trimester in pregnancy was consistently associated with milk microbial diversity and genus composition before and after adjustment for socio-demographic, maternal, and child covariates. Use of other supplements such as fish oil, folate, and calcium was less consistently associated with the breast milk microbiome.</div><div>The fourth aim of the review chapter focused on the infant gut microbiome. The effects of complementary feeding on the infant gut microbiome are less commonly studied than those of breastfeeding, with most research conducted in high-income countries but not LMIC. In contrast, associations between inadequate complementary feeding and undernutrition have been examined in LMIC where undernutrition is most prevalent. Further, a disrupted gut microbiota has been associated with child undernutrition. Indeed, animal studies have suggested a causal association although the direction of the causality is not clear and is potentially bi-directional depending on genetic and environmental conditions. In light of the current state of knowledge described in our review supporting the potential of the gut microbiota as a key player in the relation between complementary feeding and undernutrition, the development of microbiota-directed interventions during the complementary period offers a promising route for undernutrition management.</div><div><br></div><div>Findings from the studies presented in this dissertation highlight several culture-specific determinants of child growth and breastfeeding in Lebanon. The findings also highlight the need for future research using longitudinal prospective cohorts, intervention trails and animal models to provide evidence for the proposed links to enhance the understanding of the paradigm. Such a holistic view of the determinants of and pathways between infant feeding and child growth are of great public health significance to improve the health of children throughout their lives.</div>
332

The Development of the Total Nutrient Index

Alexandra Elizabeth Cowan (7040936) 18 April 2022 (has links)
<p>Dietary supplement (DS) use is highly prevalent in the U.S. and can contribute substantial amounts of micronutrients to the one-half of U.S. adults and nearly one-third of U.S. children who use them. Despite their pervasive use, the best practices for assessing the prevalence of use of and measuring nutrient intakes from supplemental sources remain largely unknown, and currently no metric designed to assess total micronutrient exposures from foods, beverages, and DS exists. Comprehensive and robust methods for assessing the prevalence of use of and nutrient intakes from DS are critical for population-level research and surveillance. </p> <p>Therefore, the overarching aims of the research presented in this dissertation were to 1) identify the most comprehensive method for assessing the prevalence of use of and estimating nutrient intakes from DS, 2) characterize DS use and examine trends in overall and micronutrient-containing DS use among the U.S. population using multiple modes of DS assessment, 3) develop the first micronutrient-based diet quality index designed to capture usual intakes from all sources of under-consumed micronutrients among the U.S. population (i.e., the Total Nutrient Index (TNI)) and 4) to determine if the TNI is a useful measure for assessing total micronutrient exposures among the U.S. adult population.</p> <p>National Health and Nutrition Examination Survey (NHANES) 2011-2014 data among U.S. adults were employed to evaluate four combinations of methods constructed from two data collection instruments (i.e., the 24-hour dietary recall (24HR) and the NHANES in-home inventory with a frequency-based DS prescription medicine questionnaire (DSMQ)) for measuring the prevalence of use of and amounts of selected nutrients from DS. The results from the analysis indicated that a higher prevalence of DS use is reported when using frequency-based methods, like the DSMQ, but higher nutrient amounts are reported on the 24HR. Thus, combining the DSMQ with at least one 24HR (i.e., DSMQ or ≥1 24HR) provides the most comprehensive approach for measuring DS use and estimating nutrient intakes from supplemental sources among U.S. adults.</p> <p>Differences in the estimated prevalence of use of DS on the DSMQ or ≥1 24HR as compared with the DSMQ only were also noted among a nationally representative sample of the U.S. population from the 2007-2018 NHANES. When characterizing DS use and examining trends in overall and micronutrient-containing DS use among the U.S. population using multiple modes of DS assessment, increases in both overall and micronutrient-containing DS use were observed over time, but the prevalence of use was lower on the DSMQ than the DSMQ or ≥1 24HR among the total population and across all population subgroups. Therefore, the findings from this study were congruent with our previous analysis and contributed to a growing body of literature that utilizes multiple methods of DS assessment to improve the comprehensiveness of DS exposure assessment. </p> <p>The insights garnered from identifying the most comprehensive method for approximating micronutrient intakes from supplemental sources were implemented in the development and initial application of the first micronutrient-based diet quality index designed to capture usual intakes from all sources of under-consumed micronutrients among the U.S. population, named the TNI. The TNI assesses U.S. adults’ total nutrient intakes relative to the Recommended Dietary Allowance or Adequate Intake for eight under-consumed micronutrients identified by the Dietary Guidelines for Americans: calcium, magnesium, potassium, choline, and vitamins A, C, D, E. In the initial application of the TNI, based on dietary data from the 2011-2014 NHANES, the mean TNI score of U.S. adults was 75.4 out of 100, whereas the mean score when ignoring contributions from DS was only 69.0 (t-test; p<0.001). Therefore, the results from this analysis suggested that the TNI extends existing measures of diet quality by including nutrient intakes from all sources.</p> <p>However, another analysis designed to examine the construct and criterion validity of the TNI was completed using data from a nationally representative sample of U.S. adults who participated in the 2011-2014 NHANES, as well as exemplary menus reflective of high-quality diets. The results showed that the TNI yielded high scores on exemplary menus (84.8-93.3 out of 100), was moderately correlated with the Healthy Eating Index-2015 (r=0.48) and was able to differentiate between groups with known differences in nutrient intake for DS users vs. non-DS users, non-smokers vs. smokers, and those who were food-secure vs. food insecure (all <em>p</em><0.001). Moreover, correlations of TNI component scores with nutritional biomarkers for vitamins A, C, D, and E were significantly higher when compared with those obtained via the diet alone.</p> <p>Taken together, the research findings from the studies presented in this dissertation contribute evidence supporting the use of multiple modes of DS assessment to improve the comprehensiveness of DS exposure assessment, as well as the importance of capturing micronutrient exposures from all sources. These results also highlight the broad applicability of the TNI framework as a tool for comprehensively representing the totality of nutrient exposures, inclusive of DS. Our outcomes point towards a need for additional investigation into the random and systematic error that pervades DS assessment, the development of tools that can be used to describe micronutrient exposures more completely and how those relate to nutritional status, as well as further applications of the TNI. </p>
333

Effect of dietary threonine level on productivity and carcass characteristics of indigenous Venda chickens

Ramuthaga, Ndivhuho January 2014 (has links)
(M.Sc. (Animal Production)) -- University of Limpopo, 2014 / Two experiments were conducted to determine the effect of dietary threonine level on productivity and carcass characteristics of indigenous Venda chickens. In each experiment the diets were isocaloric and isonitrogenous but with different dietary threonine levels. A complete randomized design was used in both experiments, the starter (1-7 weeks old unsexed chickens) and finisher (8-13 weeks old female chickens) experiments. The treatments were CT4 (4 g of threonine/kg DM), CT5 (5 g of threonine/kg DM), CT6 (6 g of threonine/kg DM), CT7 (7 g of threonine/kg DM) and CT8 (8 g of threonine/kg DM). A quadratic type of equation was used to determine dietary threonine levels for optimal feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy intake and nitrogen retention of unsexed Venda chickens aged one to seven weeks. Dietary threonine level affected (P<0.05) feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy and nitrogen retention. However, feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy and nitrogen retention of indigenous Venda chickens were optimized at different dietary threonine levels of 6.218, 6.437, 6.331, 6.655, 5.979 and 6.158 g/kg DM feed, respectively. Dietary threonine level did not affect (P>0.05) mortality rate of the chickens. The treatments for the second experiment were FT4 (4 g of threonine/kg DM), FT5 (5 g of threonine/kg DM), FT6 (6 g of threonine/kg DM), FT7 (7 g of threonine/kg DM) and FT8 (8 g of threonine/kg DM). Dietary threonine level had effect (P<0.05) on feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy and nitrogen retention of female Venda chickens aged eight to 13 weeks. Feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy intake and nitrogen retention of chickens were optimized at dietary threonine levels of 6.054, 6.142, 6.442, 6.201, 5.72 and 6.088 g/kg DM, respectively. However, dietary threonine level had no effect (P>0.05) on pH values of crop, proventriculus, gizzard, small intestine, large intestine and caecum of female Venda chickens aged 91 days. Carcass weights of female Venda chickens were affected (P<0.05) by dietary threonine level. Carcass, breast, drumstick, thigh, gizzard and liver weights of female Venda chickens aged 91 days were optimized at dietary threonine levels of 6.183, 6.201, 5.712, 5.847, 4.820 and 6.180 g/kg DM, respectively. Dietary threonine level v had effect (P<0.05) on crude protein and threonine contents of female Venda chicken meat. Meat crude protein and threonine contents of female Venda chickens aged 91 days were optimized at dietary threonine levels of 5.9 and 5.7 g/kg DM, respectively. Dietary threonine level had no effect (P>0.05) on meat flavour, tenderness and juiciness of female Venda chickens. However, meat flavour, tenderness and juiciness of female Venda chickens aged 91 days were optimized at dietary threonine levels of 5.977, 6.103 and 5.977 g/kg DM, respectively. No chicken deaths were observed. / National Research Foundation (NRF)
334

Effect of dietary citric acid supplementation & use of non-linear models on growth performance in Venda chickens

Zulu, Blantina Fangele January 2023 (has links)
Thesis (M.Sc. (Animal Production)) -- University of Limpopo, 2023 / The development curve of Venda chicken fed with various amounts of citric acid was evaluated using nonlinear models in an experiment. to ascertain the effects of citric acid supplementation level on feed intake, body weight increase, and linear measurements on Venda chickens. 200 male Venda chickens were used in the experiment which lasted 90 days. The chicks were randomly assigned to four treatments (0, 12.5, 25 and 50g of citric acid inclusion) with 5 replications, resulting in 20 floor pens with 10 chicks per replicate. A completely randomized design was employed as experimental design. Analysis of Variance (ANOVA) was used to determine the effect of citric acid on feed intake, body weight gain, FCR, GR and body linear measurements. Three different non-linear models, namely Gompertz, Weibull, and Richards, were used to define the growth curves of the Venda chickens. The Duncan multiple range test at the 5% level of significance was utilized to detect significant differences between the means. Models were compared using coefficients of determination (R2) and standard errors (SE). The results indicated that feed intake, body weight, average daily gain and growth rate of Venda chickens were not affected (p > 0.05) by citric acid supplementation levels. Similarly, Citric acid supplementation had no effects (p > 0.05) on the shank length and wing length of Venda chickens. However, feed conversion ratio (FCR) of Venda chickens was improved (p < 0.05) by with an increase in citric acid supplementation. The Venda chicken fed citric acid at grower phase and finisher phase had better growth performances than the starter phase. Citric acid supplementation improved the back length and thigh length of Venda chickens. The Venda chickens fed citric acid at 25g inclusion level significantly higher back and thigh length. The coefficient of determination ranged from 0.00 to 0.98 in all the treatments. The Gompertz Model and Richards Models both exhibited the same coefficient of determination across all treatments. The model with the lowest standard error was found to best describe the growth curve of male Venda across all treatments. The Gompertz model was observed to be suitable for explaining the growth of Venda chickens fed with feed without citric acid (CA0g) and citric acid 125g inclusion (CA12.5g). The Richards model was observed to be suitable for explaining the growth of Venda chickens fed citric acid 25g inclusion (CA25g) and citric acid 50g inclusion (CA50g). It is recommended to use a supplement containing lower citric acid to enhance the body linear measurements and growth performance of the chickens. Gompertz and Richards models can be utilized to characterize the growth curve of Venda chickens. / National Research Foundation (NRF)
335

En temporär hälsoanpassning eller kvarstående samhällsförändring? : Två Pingstförsamlingar i södra Norrland och dess digitala anpassningar vid Covid-19

Näslund Sandström, Hannah January 2022 (has links)
This study aims to investigate how the nature, structure and experience of religious life has changed in two Pentecostal churches during Covid-19 and how digital supplements were used and interpreted. A further aim is to investigate the consequences of the usage of digital media and how digital media is being used today, after the Public Health restrictions have been eased. Heidi Campbell, who is a prominent researcher in the subject of digital religion, has developed the theory Religious-social shaping of technology or RSST. The theory claims that communities' digital use is based on the community's historical background and tradition; these create common precedents that either have an innovative, accepting or deviant attitude towards new media. The material created in this study discusses through Campbell’s theory of digital usages that the impact digitalization has had on the organization, authority and community has been dominant. The result is that the churches after the easing of restrictions is resistant against digital media, since it removes the feeling of solidarity.
336

Využití výživových suplementů v jednotlivých sportovních odvětvích / Use of Nutritional Supplements in Individual Sport Sectors

Weiser, Martin January 2015 (has links)
The aim of the diploma thesis was to determine, which nutritional supplements are selected by athletes of strength and endurance sports branches and what is the reason for their option. The theoretical part characterizes the 8 selected sports sector from point of view of the sport performance structure. There is also mentioned the issue of nutritional supplements, their division, legislation or general recommendations for the use in sport. The last chapter deals with the requirements for the use of nutritional supplements in different periods with respect to the branche of sport. Research part has specifically determined the nutritional strategy for athletes in the field of mentioned food supplements at strength and endurance-oriented sports disciplines by using the questionnaire. The research is supported by an interview with an expert nutritionist and sports through collaboration with the staff of the Centre for Sports of the Ministry of Interior
337

Effects of two levels of dietary energy supplementation and rearing systems on growth and carcass characteristics of grower pigs

Makgothi, Onkabetswe Gogakgamatsamang January 2012 (has links)
Thesis (M. Tech. Agriculture) -- Central University of Technology, Free state, 2012 / The eight-week study was conducted to evaluate the effects of rearing system (indoor vs. outdoor) and energy level on digestibility, growth performance and on the carcass characteristics and visceral organs of pigs. A total of 48 Large Whites (LW) X Landrace (LR) male grower pigs were randomly selected at average weights of 27 ± 4.6.kg and divided into two equal groups that were either raised indoors or outdoors. Within each rearing system, half the pigs were fed on a diet formulated to contain either a normal energy level (14 MJ DE/kg) or high energy level (16.1 MJ DE/kg) resulting in a 2 X 2 factorial design. The pigs were fed ad libitum and water was freely available. Pigs were housed in pairs and each indoor and outdoor pig was offered a space allowance of 0.51 and 13.5 m2 respectively. Indoor pigs were raised in a temperature controlled house consisting of a concrete floor pen while outdoor pigs were on a pasture that predominantly consisted of Kikuyu. Movable gates were used to construct outdoor camps and empty feed bags were used to construct a shade for use as shelter. Faecal collection for digestibility determination took place during week 7 while the growth performance trial was still in progress. Chromium oxide was used to evaluate digestibility and faeces were grabbed before they fell to the ground and sampled. With the exception of ether extracts (EE), the digestibilities of crude protein (CP), digestible energy (DE), crude fibre (CF), neutral detergent fibre (NDF), acid detergent fibre (ADF) and organic matter (OM) were reduced (P <0.05) by rearing pigs outdoors. EE followed the same trend. Feeding the high energy (HE) diet significantly (P >0.05) improved the digestibilities of all the nutrients except for CP. There were no significant interactions (P>0.05) between rearing system and diet for the digestibility of nutrients. Daily gains were similar (P >0.05) between indoor and outdoor pigs. Daily feed intakes and conversions were significantly (P <0.05) lower in indoor pigs. There were no significant (P >0.05) differences between the daily gains and feed conversions of pigs fed either the normal energy (NE) or the HE diet. Indoor pigs fed the HE diet had lower (P < 0.05) feed intakes compared to pigs on the other treatments. In general, average daily feed intakes (ADFI) of the HE fed pigs were significantly (P <0.05) lower than those of the NE fed pigs. The carcass measurements of the indoor and outdoor pigs were similar. The gastro-intestinal tract (GIT) and the liver weights of the outdoor reared pigs were significantly (P <0.05) heavier than those of the indoor reared pigs. Feeding the HE diet led to significantly (P <0.05) higher carcass weights and dressing percentages. Interactive effects (P <0.05) of diet and rearing system were found for lean meat percentage (Lean P) and eye muscle area (EMA). Indoor pigs fed on the NE diet had higher Lean P and EMA while an opposite effect was obtained in the outdoor system. The liver of the NE diet fed pigs was significantly (P < 0.05) heavier than that of the pigs fed the HE diet. It can be concluded that with regard to growth performance and carcass characteristics, the NE and HE diets are respectively best suited for the indoor and outdoor rearing of pigs.
338

The role of ethical business behaviour awareness in consumer sports supplement purchase intentions

Gottsche, Louise Theresia 27 July 2011 (has links)
The gap between ethical purchase intentions and ethical purchase behaviour is well-documented. Although this gap can be bridged by increasing the level of awareness among consumers with regards to ethical business practices, it was found that consumers between the ages of 19 to 56 years were already aware of ethical organisations and business practices in the South African sports supplement industry. They are however unaware of companies that operate unethically. Several factors such as brand familiarity, price and convenience were found to compete with ethical business behaviour during the purchase decision-making process. It is thus recommended that organisations that incorporate ethical business behaviour at a strategic level should provide ethical products that are competitively priced, convenient to use and from a brand that is familiar / Graduate School of Business Leadership / MBA
339

The relative efficacy of Advanced Brain Food and a homeopathic complex (Quietude) in the management of Attention Deficit Hyperactivity Disorder (ADHD) in males between the ages of 8 and 13 years

Lottering, John-John Brian January 2006 (has links)
Thesis (M.Tech.: Homoeopathy)-Dept. of Homoeopathy, Durban Institute of Technology, 2006 xxv, 261 leaves / The aim of the study was to evaluate the efficacy of a Nutritional Supplement (Advanced Brain Food®) and a homoeopathic complex (Quietude®) in the management of Attention Deficit Hyperactivity Disorder (ADHD). ADHD is primarily a childhood disorder affecting ten to twenty percent of school going children. The three main presenting features of ADHD are inattention, impulsivity, and hyperactivity. This triad often results in numerous adjustment difficulties for the child in the social and academic sectors (NIH Consensus Statement, 1998).
340

Impact of vitamins B12, B6 and folate supplementation on cardiovascular risk markers in an elderly community of Sharpeville

Grobler, Christina Johanna 09 1900 (has links)
Submitted in fulfillment of the requirements of the degree of Doctor of Technology: Health Sciences, Durban University of Technology, Durban, South Africa, 2015. / Background: In a vulnerable low-income group with a confirmed high risk of cardiovascular disease, like the elderly in the Sharpeville care centre, an acute intervention is needed in order to improve their health profile. Previous studies suggested homocysteine lowering by vitamin B12, B6 and folate supplementation. The effect of vitamin B12, B6 and folate supplementation on the inflammatory response, thrombotic risk, lipid profile, hypertension, risk of metabolic syndrome and homocysteine metabolism in an elderly, black South African population has never been reported. Objectives: The main aim of this interventional study was to assess the effect of vitamins B12, B6 and folate supplementation at 200% RDA for six months on cardiovascular risk markers of an elderly semi-urbanised black South African community. Design: This study was an experimental intervention non-equivalent control group study design in 104 purposively selected samples of all the elderly attending the day-care centre. Setting and participants: A homogeneous group of respondents was included in the study. All subjects were equivalent in age (>60 years), race (black), unemployed/pensioners (socio-demographic) and 60 years and older attending a day care centre in Sharpeville, situated in the Vaal region, Gauteng, SA. Measurements: The distinctiveness of this study lies in the broad panel of parameters evaluating the CVR in correlation with the increased nutritional intake of vitamin B6, B12 and folate. These included: weight, height, waist, serum cholesterol, high density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides, blood pressure, fibrinogen, high-sensitivity C-reactive protein (HS–CRP), homocysteine, vitamin B12, folate, glucose, insulin, adiponectin and fibronectin. Results: A very high incidence (66.36%) of hyperhomocysteinaemia is present in the sample. The mean serum homocysteine level in hyperhomocysteinaemic individuals decreased statistically significantly from 25.00±8.00 umol/l to 18.80±12.00 umol/l after the intervention. The number of respondents with an increased homocysteine level decreased from 100% (baseline) to 67% (follow-up). The supplementation was beneficial (statistically significant changes) to the glucose levels, fibrinolytic status, vitamin B6 serum levels, fibronectin levels and haemopoeiesis (decreased macrocytosis) of all the individuals (regardless of their homocysteine status). Conclusion: It is concluded that supplementation of vitamins B6, B12 and folate at 200% RDA for six months is an effective homocysteine-lowering approach as a strategy to reduce hyperhomocysteinaemia in an elderly population and thereby reduce cardiovascular risk (CVR). The supplementation intervention mentioned is not an effective multifactorial strategy to decrease CVR although beneficial effects were found with other CVR markers independent of homocysteine status.

Page generated in 0.1213 seconds