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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.
71

Determining the water needs of dairy cattle

Potts, Justin C. January 1900 (has links)
Master of Science / Department of Animal Science and Industry / Micheal J. Brouk / Data obtained from 50 individual published studies recording water intake by dairy cattle were utilized in a meta-analysis to develop a prediction equation for free water intake (FWI). Studies were selected based on quantitative measurements of DMI, diet DM%, water intake (WI), and milk yield. Many of the studies determined FWI on multiple treatments resulting in 116 mean data points from the 50 studies. With the addition of Na in the meta-analysis, 40 data points were available from the studies to examine the effects of Na on FWI. The effects of DMI, ration water intake (RWI), and milk yield (MY) were used to develop a FWI prediction equation from the 116 data points. The effects of DMI, RWI, MY, and sodium intake were used to develop a second prediction equation from the 40 data points. These equations were then compared with five published FWI prediction equations from Castle and Thomas (1975), Dahlborn et al. (1998), Little and Shaw (1978), Murphy et al. (1983) and Stockdale and King (1983). This data set showed that the five published equations either over or under predicted (P < 0.05) FWI when compared the actual FWI calculated from the meta-analysis data points. It also showed that the equation developed from the meta-analysis data points is the more accurate in determining FWI from the data points selected from the studies. A second project was conducted with the fresh water data collected from 13 freestall (FS) and 11 dry lot (DL) Kansas dairies over a 10-year period (2000-2009). Fresh water was recorded from water pumping records. Data were first summarized annually by operation and then converted to a per cow per day basis prior to analysis. Data were then analyzed by using the mixed procedures of SAS. Fixed effects included in the model were dairy type (FS or DL) and year was considered a random effect. The DL dairies averaged 186 L/cow per day and were lower than the FS dairies which averaged 237 L/cow per day. Differences between DL and FS style dairies may have been due to differences in parlor fresh water usage or cow cooling systems.
72

Aerodynamic Optimization of Compact Engine Intakes for High Subsonic Speed Turbofans

Udit Vyas (6636125) 10 June 2019 (has links)
<p>Within the gas turbine industry, turbofan engines are widely implemented to enhance engine efficiency, specific thrust, and specific fuel consumption. However, these turbofans have yet to be widely implemented into microgas turbine engines. As turbofans become implemented into smaller engines, the need to design engine intakes for high-speed mission becomes more vital. In this work, a design procedure for compact, highly diffusive engine intakes for high subsonic speed applications is set about. The aerodynamic tradeoffs between cruise and takeoff flights are discussed and methods to enhance takeoff performance without negatively impacting high-speed cruise performance is discussed. Intake performance is integrated into overall engine analysis to help guide future mission analyses. Finally, an experimental model for engine intakes is developed for application to linear wind tunnels; allowing future designers to effectively validate numerical results.<br></p> <p>A multi-objective optimization routine is performed for compact engine intakes at a Mach number of 0.9. This optimization routine yielded a family of related curves that maximize intake diffusive capability and minimize intake pressure losses. Design recommendations to create such optimal intakes are discussed in this work so that future designers do not need to perform an optimization. Due to high diffusion rate of the intake, the intake performance at takeoff suffers greatly (as measured by massflow ingestion). Methods to enhance takeoff performance, from designing a variable geometry intake, to creating slots, to sliding intake components are evaluated and ranked for future designers to get an order of magnitude understanding of the types of massflow enhancements possible. Then, off-design performance of the intake is considered: with different Mach number flights, non-axial flow conditions, various altitudes, and unsteady engine operation considered. These off-design effects are evaluated to generate an intake map across a wide engine operational envelope. This map is then inputted into an engine model to generate a performance map of an engine; which allows for mission planning analysis. Finally, various methods to replicate intake flow physics in a linear wind tunnel are considered. It is shown that replicating diffuser curvature in a linear wind tunnel allows for best replication of flow physics. Additionally, a method to non-dimesnsionalize intake performance for application to a wind tunnel is developed. </p> <p>This work can be utilized by future engine intake designers in a variety of ways. The results shown here can help guide future designers create highly compact diffuser technology, capable of operating across a wide breadth of conditions. Methods to assess intake performance effects on overall engine performance are demonstrated; and an experimental approach to intake analysis is developed.</p>
73

Effect of acute exercise on energy intake, physical activity energy expenditure and energy balance hormones in sedentary and active men

Silalertdetkul, Supaporn January 2009 (has links)
An exercise-induced energy deficit may affect post-exercise energy intake, physical activity energy expenditure (PAEE) and energy balance hormones. Therefore, the objective of this thesis was to investigate the impact of a single bout of exercise either of moderate (40% O2max) or high (70% O2max) intensity on post-exercise energy intake, physical activity energy expenditure and energy balance hormones in both sedentary and active males. Physical activity energy expenditure increased between 38 and 62 hours following moderate intensity exercise in sedentary males (Chapters 3 and 4). This was due to increased light intensity energy expenditure (2.4-4.79 METs) such as standing and walking activities (Chapter 4). The Change in PAEE was not associated with circulating leptin and adiponectin concentrations. There was no impact of a single bout of exercise on post-exercise energy intake in sedentary males during a buffet meal (Chapter 4). Chapter 5 aimed to determine whether changes in PAEE, energy intake, and energy balance hormones were related to physical activity status. Interestingly, plasma acylated ghrelin concentration was suppressed while total peptide YY (PYY) concentration tended to be elevated after high intensity exercise in active males (Chapter 5). However, there was no impact of either moderate or high intensity exercise on PAEE and post-exercise energy intake in active males. The final study (Chapter 6) determined whether high intensity exercise in the fed state after a few days of food restriction had an impact on circulating energy balance hormones. Circulating postprandial total PYY and pancreatic polypeptide (PP) were increased for one hour after high intensity exercise in active men. There was no change in PAEE and post-exercise energy intake after exercise.
74

The Effects of Long Term Modernate Ethanol Intake on Plasma Levels of ACTH, Beta Endorphin, and Corticosterone in Rats

Breedlove, Kenneth 12 1900 (has links)
The effects of single injections and daily oral administration of ethanol on plasma levels of ACTH, beta endorphin, and corticosterone in response to cold stress were examined. The long-term experimental animals were given 0.25 ml of 28% ethanol or water orally once a day, five days a week, for fourteen months. Plasma levels of ACTH, beta endorphin, and corticosterone were lower in alcohol-treated rats as compared with water-treated rats when exposed to cold stress. The effects of a single injection of ethanol significantly elevated plasma levels of all three hormones. Mortality in sham-treated males was higher than ethanol-treated.
75

A Multiday Record-Assisted Fruit, Vegetable, and Snack Questionnaire to Assess Intake Among Fourth and fifth Grade Students

Lambert, Anne B. 01 May 2013 (has links)
Assessing FV intake among young children is difficult and can be a time- consuming, resource-intensive, and burdensome. The aim of this study was to create a simple, self-assessment tool to estimate and detect changes in FV consumption among fourth and fifth graders. Such a tool would ease the complications and resources of other diet assessment options that are used to measure FV consumption when implementing school-based nutrition programs.The questionnaire provided a moderately valid estimate of lunchtime FV consumption, but it was inconsistent at detecting small, yet important increases in FV consumption between time points. The ability of the questionnaire to measure total FV consumption was also tested and found to be poor. In addition, having the students record what they ate on a food tracker during meals did not improve performance on the questionnaire.The tool examined in this study could provide a reasonable estimate of average lunchtime FV consumption among fourth and fifth grade children, but could not be used to detect sensitive changes in consumption during a FV intervention study. While it is difficult for children to recall dietary information, it beneficial to continue to explore the development of a self-report questionnaire that can accurately assess total FV intake in children.
76

Examining the Association Between Children's Fruit and Vegetable Intake at and Away from School

Yaa Ankrah Ansu, Velarie 01 August 2015 (has links)
Several school-based interventions aimed at increasing fruit and vegetables (FV) intake among children have demonstrated success in short-term interventions. The Fit Game is a school-based intervention aimed at encouraging children to consume increasing amounts of FV during a game, which is a narrative. Just as children are being encouraged to eat FV at school, so is it equally important for them to eat FV at home. Parents strongly influence the amount of FV children consume at home. The aim of this thesis is to examine associations between factors that influence consumption of fruits and vegetables at and away from school among children who are participating in a schoolbased intervention, which has been shown to increase fruit and vegetable consumption at school. Associations between factors of the home environment and FV intake of children at and away from school are also explored. The study population was 37 parent-child pairs who participated in the Fit Game intervention conducted at one elementary school in 2013 (n = 252). This study showed that there was an increase in FV intake of children at school during the period they played the Fit Game; however there was no change in fruit and vegetable intake away from school during that same period of time. In addition, though parents and children’s intake of FV were correlated, parents did not change their FV intake during the period of time their child participated in the Fit Game at school. There was no significance between children’s intake and the factors in the home environment including family meals, FV accessibility and availability as well as parental knowledge. This study used rigorous methods to assess dietary intake. It is, however, important that this study is replicated with a larger sample that is more diverse.
77

Hemodialyspatienters självrapporterande saltvanor

Persson, Ann-Christine, Halvarsson, Anna-Karin January 2008 (has links)
<p>The purpose of the study was to describe hemodialysis patients self-reporting salt habits associated with cooking and food intake. Furthermore, the purpose was to investigate possible differences in inter Dialyze significant weight gain at low and high self-reported salt consumption. The study was an empirical descriptive study of comparative features and consisted of a convenience sample from two hemodialysis units in southern Norrland. Study group consisted of 37 persons who had been ongoing hemodialysis treatment and their age ranged from 42-86 years. A questionnaire was used in two parts and both parts contained 15 foods. The first part was stated how often the food consumed in a week on the basis of six possible answers. In the second set of salt to the cooking in and / or eating for the food on the basis of four possible answers. Information on age, gender and type of accommodation indicated in the survey and data on weight before and after dialysis was collected from the medical record. The results showed that the study group predominantly consumed foods that have a moderate natural salt content. Half of the study group ate soft bakery bread baked daily and only 16 people at homemade bread less than once a week. Participants put extra salt to all eligible food and salted also on the green salat. There was no difference in inter Dialyze weight gain at the high and low self-reported salt consumption.</p>
78

Evaluation of a mathematical model in predicting intake of growing and finishing cattle

Bourg, Brandi Marie 10 October 2008 (has links)
The Cattle Value Discovery System (CVDS) was developed to predict growth and feed requirements of individual cattle fed in groups based on animal, diet, and environment information (Tedeschi et al., 2006). Evaluations of the CVDS using several databases of finishing cattle were conducted to determine the accuracy and precision of the model in predicted dry matter required (DMR) of pen-fed cattle. As well, the sensitivity of the model's predictions to deviations from actual ration metabolizable energy (ME) value was conducted. A meta-analysis of growing and finishing steers evaluated to model's accuracy in predicting DMR of individually fed steers, and the relationships between several model-predicted variables and actual performance and efficiency measures. Results for the first CVDS model evaluation involving pen-fed Santa Gertrudis cattle fed finishing diets revealed that accurate predictions of DMR are possible. The average mean bias for both steers and heifers was 2.43%. The sensitivity analysis of dietary ME values revealed that the model tends to consistently over- and under-predict DMR when the ME values are under- and over-estimated, respectively. However the ranking of pens was not affected by this mis-estimation of diet ME. In the second evaluations, both methods (mean body weight; MBW, dynamic iterative model; DIM) of CVDS were highly accurate and precise in allocating feed to pens of steers fed diverse types of diets and environmental conditions, with both models having a mean bias under 4%. The DIM model was slightly more accurate than the MBW model in predicting DMR. An evaluation of sources of variation revealed that for both models a large portion of the error was random, indicating that further work is needed to account for this variation. The meta-analysis study revealed that the model was able to account for 64% and 67% of the variation in observed dry matter intake (DMI) for growing and finishing steers, respectively. The two model-predicted efficiency measures, the ratio of DMR to average daily gain (ADG) and predicted intake difference (PID), were strongly to moderately correlated with their observed efficiency counterparts. In growing and finishing steers, DMR: ADG was able to account for 76% and 64% of the variation in observed feed conversion ratio (FCR) in growing and finishing studies, respectively. Strong correlations were also found between residual feed intake (RFI) and PID, suggesting that there may also be some similarity on these two measurements.
79

Evaluation of a mathematical model in predicting intake of growing and finishing cattle

Bourg, Brandi Marie 15 May 2009 (has links)
The Cattle Value Discovery System (CVDS) was developed to predict growth and feed requirements of individual cattle fed in groups based on animal, diet, and environment information (Tedeschi et al., 2006). Evaluations of the CVDS using several databases of finishing cattle were conducted to determine the accuracy and precision of the model in predicted dry matter required (DMR) of pen-fed cattle. As well, the sensitivity of the model’s predictions to deviations from actual ration metabolizable energy (ME) value was conducted. A meta-analysis of growing and finishing steers evaluated to model’s accuracy in predicting DMR of individually fed steers, and the relationships between several model-predicted variables and actual performance and efficiency measures. Results for the first CVDS model evaluation involving pen-fed Santa Gertrudis cattle fed finishing diets revealed that accurate predictions of DMR are possible. The average mean bias for both steers and heifers was 2.43%. The sensitivity analysis of dietary ME values revealed that the model tends to consistently over- and under-predict DMR when the ME values are under- and over-estimated, respectively. However the ranking of pens was not affected by this mis-estimation of diet ME. In the second evaluations, both methods (mean body weight; MBW, dynamic iterative model; DIM) of CVDS were highly accurate and precise in allocating feed to pens of steers fed diverse types of diets and environmental conditions, with both models having a mean bias under 4%. The DIM model was slightly more accurate than the MBW model in predicting DMR. An evaluation of sources of variation revealed that for both models a large portion of the error was random, indicating that further work is needed to account for this variation. The meta-analysis study revealed that the model was able to account for 64% and 67% of the variation in observed dry matter intake (DMI) for growing and finishing steers, respectively. The two model-predicted efficiency measures, the ratio of DMR to average daily gain (ADG) and predicted intake difference (PID), were strongly to moderately correlated with their observed efficiency counterparts. In growing and finishing steers, DMR: ADG was able to account for 76% and 64% of the variation in observed feed conversion ratio (FCR) in growing and finishing studies, respectively. Strong correlations were also found between residual feed intake (RFI) and PID, suggesting that there may also be some similarity on these two measurements.
80

Nutritional consequences in children undergoing chemotherapy for malignant disease

Skolin, Inger January 2005 (has links)
Background: Chemotherapy has side effects that may interfere with food intake. Children suffering from a malignant disease are subjected to treatment with chemotherapy. They may therefore become at risk of undernutrition during the period of treatment. This in turn may increase the risk of infections, delayed therapy and influence the outcome of treatment. Few studies have investigated how children undergoing chemotherapy for cancer perceive food and eating. Attempts to improve food intake and the nutritional status require an understand-ing of how eating patterns are altered during chemotherapy in children. Study design: Dietary information and anthropometric data were collected after the initiation of chemotherapy in 14 children, consecutively admitted to the Paediatric Haematology and Oncology Unit at Umeå University Hospital. This initial study resulted in the establishment of more flexible mealtime routines on the ward. A follow-up study was conducted with another group of 11 children. Interviews were performed with a third group of 21 consecutively ad-mitted children, their parents and attending nurses. The focus was on the children’s own per-ception of and their parents’ and nurses’ attitudes to their food intake during hospitalisation. Recognition thresholds for the basic tastes were determined with 10 of the oldest of these children and 10 healthy controls. Results: Before introduction of new mealtime routines, the average daily oral energy intake during hospitalisation was 58% of the Swedish Nutrition Recommendations, SNR. The chil-dren had a significant weight loss up to three months after onset of chemotherapy. After the introduction of new mealtime routines, the average daily oral intake on hospital days was 61% of SNR and thus still lower than recommended despite efforts to serve palatable food on the ward. When enteral and parenteral nutrition was included, the energy intake came close to that recommended for healthy children, 91% of SNR. Both children and parents perceived that altered taste was an important cause of the children’s eating problems. The children also viewed food aversions, nausea and vomiting and pain as important causes, while the parents perceived nausea, food aversions and altered smell as significant factors. The nurses on the other hand, viewed nausea, the ward environment, and food rejection as a way of gaining some influence over the situation as important factors. The patients had significantly higher thresholds for bitter taste and significantly more patients made mistakes in taste recognition compared with controls. Conclusion and clinical implication: There seem to be changes both in the sense of taste as well as in the perception of food in children undergoing chemotherapy for malignant disease. Thus, single solutions such as providing a variety of “tasty food” in the hospital setting in order to improve food intake does not suffice for many paediatric cancer patients. The indi-vidual’s food preferences and aversions should be considered and combinations of oral, en-teral and parenteral nutrition support should be provided.

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