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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.
21

Physical activity and obesity in children: measurement, associations, and recommendations

Duncan, Scott January 2007 (has links)
Widespread increases in the prevalence of childhood obesity have raised the prospect of serious public health consequences in many countries. New Zealand is no exception; according to the most recent national estimates, approximately one in three children is overweight or obese. As a consequence, an understanding of the specific risk factors that predict this condition in children is becoming increasingly important. It is generally accepted that the promotion of physical activity is a key strategy for reducing the risk of childhood obesity. However, there is limited information describing physical activity and its relationship with body fatness in young New Zealanders. The overall aim of this thesis was to gain insight into the associations between excess fatness and physical activity in New Zealand children from a diverse range of socio-demographic groups. Three related studies were conducted to achieve this aim: a large descriptive survey of obesity and physical activity patterns in primary-aged children, and two preceding studies which develop the methodology for objective assessment of physical activity in this population. The first study provided the only validation data for the NL-2000 multiday memory (MDM) pedometer in children. In a sample of 85 participants aged 5-7 and 9-11 years, the NL-2000 offered similar accuracy and better precision than the widely used SW-200 pedometer (NL-2000: mean bias = -8.5 ± 13.3%; SW-200: mean bias = -8.6 ± 14.7%). The second study investigated reactivity to wearing pedometers over four 24-hour testing periods in 62 children aged 5-11 years. The sample was divided into two groups: one was given a full explanation of the function of the pedometer, while the other received no information prior to testing. The absence of significant differences in step counts between the first and last test periods indicated that there was no evidence of reactivity to this device for either preparation procedure. The central study presented in this thesis was the measurement of physical activity, body composition, and dietary patterns in 1,226 children aged 5-12 years, from which four chapters (4-7) were derived. The sample was ethnically diverse, with 46.8% European, 33.1% Polynesian, 15.9% Asian, and 4.1% from other ethnicities. Physical activity levels over three weekdays and two weekend days were assessed using NL 2000 pedometers. Percentage body fat (%BF) was determined using hand-to-foot bioelectrical impedance analysis with a prediction equation previously developed for New Zealand children. Waist and hip girths, height, and weight were measured using standard anthropometric techniques. Parent proxy questionnaires were used to assess demographic and lifestyle factors and pedometer compliance. The first reported analyses of this dataset (Chapter 4) examined the effect of weather conditions on children’s activity levels. In boys, a 10ºC rise in ambient temperature was associated with a 10.5% increase in weekday steps and a 26.4% increase in weekend steps. Equivalent temperature changes affected girls’ step counts on weekdays only (16.2% increase). Precipitation also had a substantial impact, with decreases in weekday and weekend step counts during moderate rainfall ranging from 8.3% to 16.3% across all sex, age, and socioeconomic (SES) groups. The aim of Chapter 5 was to understand the relationship between children’s step counts and their body mass index (BMI), waist circumference (WC), and %BF. Mean step counts for this sample were 16,133 ± 3,864 (boys) and 14,124 ± 3,286 (girls) on weekdays, and 12,702 ± 5,048 (boys) and 11,158 ± 4,309 (girls) on weekends. Significant associations were detected between steps.day-1 and both WC and %BF, but not between steps.day-1 and BMI. The findings in Chapter 6 extended these results by estimating the number of steps required to reduce the risk of excess adiposity in children (16,000 and 13,000 steps.day-1 for boys and girls, respectively). Finally, the study described in Chapter 7 examined the associations between excess adiposity and a series of demographic and lifestyle variables, providing the first assessment of body fat correlates in young New Zealanders. Our results indicated that children aged 11-12 years were 15.4 times more likely to be overfat (boys, %BF ≥ 25%; girls, %BF ≥ 30%) than those aged 5-6 years. In addition, the odds of overfat were 1.8 times greater in Asian children than in European children, and 2.7 times greater in the low SES group when compared with the high SES group. Three modifiable behaviours related to fat status were also identified: low physical activity, skipping breakfast, and insufficient sleep on weekdays. Clustering of these risk factors resulted in a cumulative increase in the prevalence of overfat.
22

Distribuce tukové tkáně u dětí předškolního věku - srovnávací studie / Adipose tissue distribution by preschool children- comparative study

Petrů, Dominika January 2014 (has links)
CHARLES UNIVERSITY IN PRAGUE FACULTY OF PHYSICAL EDUCATION AND SPORT ADIPOSE TISSUE DISTRIBUTION BY PRESCHOOL CHILDREN- COMAPARATIVE STUDY ABSTRACT Head of the dissertation: Author: Prof. MUDr. Ivan Dylevský, DrSc. Mgr. Dominika Petrů Prague, 2014 Abstract The dissertation provides information about the distribution of subcutaneous adipose tissue in preschool-aged /5-6 years, n=141/ and younger school-aged children /8- 9 years, n=137/ in the Ústí region. In this review, we describe and evaluate the child's body with anthropometric parameters, skinfold, bioelectrical impedance analysis and selected sample /n=31/ with ultrasonography. We found an increased distribution of adipose tissue in older file with a concentration in the abdominal area and a higher reliability of skinfold than the BIA, considering the ultrasound examination. Key words: subcutaneous fat, skinfold, bioelectrical impedance analysis, ultrasonography
23

Desenvolvimento de um sistema de espectroscopia de impedância elétrica multicanal / Multichannel electrical impedance spectroscopy system

Pereira, Rogério Martins 30 July 2009 (has links)
Made available in DSpace on 2016-12-12T17:38:36Z (GMT). No. of bitstreams: 1 Rogerio Martins Pereira.pdf: 8981376 bytes, checksum: 99bc38e35b4ba47ede892b1ed9f09d6b (MD5) Previous issue date: 2009-07-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Over 40 years the Electrical Impedance Spectroscopy (EIS) has been used to investigate pathologies in biological tissues by analyzing its electrical properties and associate them to a tissue equivalent circuit model. The EIS technique consists of applying a multifrequency current of constant amplitude by two electrodes, measuring the resulting potential by other two electrodes and then extract the electrical parameters from a tissue model by calculating the transfer impedance (ZT). The main objective of this work is to develop an EIS multichannel system for impedance probes within the frequency range of 500 Hz to 1 MHz. A voltage controlled current source (VCCS) circuit and a fully controlled multiplexing system were developed. The potentials were measured by a Data Acquisition (DAQ) board. A software developed in LabVIEW was implemented in order to control and calibrate the hardware, and also to process the data in the calculation of the complex impedance and its electric tissue parameters. In order to present the data and to get an easy-to-use front panel, a graphical interface was developed. This allows one to select both injecting and measuring channels, to present the measured signal in real time and in the frequency domain, which can be chosen between the modulus and phase of the transfer impedance ZT. Preliminary tests were made in the hardware by using resistive loads. The results showed that the frequency response of the developed EIS multichannel system is band limited. Therefore, a compensation process technique was implemented and then fully tested. The results showed that the compensation technique increases the accuracy of the system to approximately 95% in the range of 500 Hz to 1 MHz, with resistive loads. Measurements in tissue equivalent circuits (phantoms) were made and its electrical tissue parameters were calculated. The results showed that the measured data can be easily fitted to the phantoms with a maximum error of 5%. Tissue impedances were measured by an electrode impedance probe. Firstly, the probe was calibrated by using saline solutions with conductivities from 1,0 to 10,0 mS/cm. The objective was to reconstruct the conductivities from measured data. The results showed na accuracy of 98% in the reconstruction within the frequency range of 500 Hz to 200 kHz. Second, measurements in five different samples of bovine tissue were made and their respective electrical parameters were calculated. In order to characterize the bovine tissue, the reactive part of the transfer impedance was plotted against the resistive part and their respective electric parameters were calculated. It can be concluded that the performance of the developed EIS multichannel system was achieved in the frequency range of 500 Hz to 200 kHz. Stray capacitances from the multiplexing system, cable capacitances and the input capacitance of the DAQ board reduced the system frequency range. However, feasible tissue data can be obtained by this system and so tissue characterization may be performed for pathologies identification. / O processo em Espectroscopia de Impedância Elétrica (EIE) para levantamento da impedância elétrica consiste na injeção de uma corrente CA de amplitude constante, ao longo de uma faixa de freqüência, através de dois eletrodos, na medição do potencial resultante e, então, no cálculo da impedância de transferência ZT. EIE é uma técnica usada na determinação de patologias em tecidos biológicos através da análise dos parâmetros elétricos equivalentes do tecido. Estes parâmetros são obtidos através da medição da impedância de transferência do material analisado. O objetivo deste trabalho é desenvolver um sistema EIE multicanal, utilizado em sondas com até oito eletrodos, operando na faixa de freqüência de 500 Hz a 1 MHz. No circuito eletrônico do sistema foi desenvolvida uma fonte de corrente controlada por tensão e um sistema de multiplexação e demultiplexação. Através de uma placa de aquisição de dados, uma plataforma de controle foi desenvolvida em LabVIEW, dispondo de funções especiais para o cálculo da impedância complexa e dos parâmetros elétricos dos tecidos, para a calibração e o armazenamento dos dados. Também foi desenvolvida uma interface gráfica amigável para a manipulação dos dados e seleção dos canais de medição e apresentação dos sinais medidos em tempo real e no domínio da freqüência através do espectro da impedância ZT e das suas componentes: módulo e fase. Testes foram realizados no sistema utilizando cargas puramente resistivas. Os resultados mostraram que o sistema EIE responde de maneira não linear com a freqüência. Após o processo de compensação, obteve-se uma exatidão de 95% na faixa de 500 Hz a 1 MHz. Medições em phantoms (circuitos equivalentes elétricos de tecidos) foram feitas, mostrando que seus respectivos parâmetros podem ser calculados com uma exatidão média de 95%. Utilizando uma sonda de eletrodos, o sistema EIE+sonda foi calibrado através de soluções salinas com condutividades na faixa de 1,0 a 10,0 mS/cm. Os resultados mostraram uma exatidão de 98% no cálculo das condutividades até 200 kHz. Medições feitas em leite de vaca mostraram que é possível identificar o seu teor de gordura. Medições em cinco amostras diferentes de tecido bovino foram feitas e seus respectivos parâmetros elétricos foram calculados. De maneira geral, o sistema EIE multicanal desenvolvido apresentou desempenho satisfatório, embora capacitâncias parasitas nos circuitos, no cabo da sonda e na placa de aquisição prejudicaram sua exatidão nas altas freqüências. Pode-se concluir que é de fundamental importância o uso de técnicas de compensação e calibração para que medições em tecidos biológicos sejam possíveis com este equipamento.
24

Correlation between how glucagon levels reflect obesity in children with regards to weight, fat mass and fat free mass

Ibrahimović, Adisa January 2016 (has links)
Background: Overweight and obesity constitutes a threat to public health all around the world, and more individual’s dies from obesity than from hunger. This condition is increasing worldwide and obesity also occurs in children. According to WHO, there are 42 million overweight children in the world. Obesity and overweight in childhood leads to insulin resistance, elevated blood lipids and cardiovascular effects. Obesity is caused by positive energy intake, poor exercise habits, environmental factors, food habits and stress etc. It is also known that hormones influence the incidence of obesity. It has been found that individuals with overweight and obesity has elevated glucagon levels in the bloodstream Purpose: This work aims to investigate whether there is a difference in glucagon concentration between the sexes at ages 10-18 years with obesity, and if there is an association between glucagon concentration and weight, FM and FFM. Materials and Methods: In this study, obesity is determined by BIA and the caliper in combination as three compartment model. Blood samples were taken by venipuncture and glucagon were analyzed in fasting plasma. Results: BIA and the caliper together had a significant correlation with body composition. Blood glucagon was found to be high in obese children. Conclusion: Glucagon concentration in obese children correlates with weight and FM. However, further investigation is needed regard to how glucagon interact with weight, FM and FFM
25

The relationship between the lumbar lordosis, body fat percentage, lumbar spine range of motion, physical activity level and the incidence of low back pain in females

De Albuquerque, Veronica 17 April 2013 (has links)
M.Tech. (Chiropractic) / Purpose: Low back pain affects the general population worldwide. Low back pain is a multi-factorial problem with debate as to the exact aetiology of low back pain. Thus, this study examines the relationship between lumbar spine lordosis, body fat percentage, physical activity level, lumbar spine range of motion and the incidence of low back pain. Method: There was a total of one hundred female participants between and including eighteen and thirty-five years of age. These females were symptomatic or asymptomatic of mechanical low back pain. Potential candidates were examined and accepted based on the inclusion and exclusion criteria. Participants were evaluated once. No treatment was administered. Procedure: Subjective responses were acquired through the Visual Analog Scale, the International Physical Activity Questionnaire and an Oswestry Low Back Pain and Disability Questionnaire. The objective evaluation included a physical examination and a lumbar spine regional examination. The participant’s height was measured using a stadiometer. The Bioelectrical Impedance Analysis (BIA) measured the participant’s weight, water content, lean tissue mass and body fat percentage. BMI was calculated from the weight and height recordings. Range of motion of the lumbar spine was measured with a Digital Inclinometer. A flexi curve ruler molded the lumbar spine lordosis of each participant, which was then traced onto a piece of paper to measure the magnitude of lumbar spine lordosis. Results: A clinical relationship did not exist between a hyperlordotic lumbar spine posture, the incidence of low back pain, body fat percentage and lumbar spine range of motion. A clinical relationship was evident between a hyperlordotic lumbar spine posture and the level of physical activity. Conclusion: Given that a clinical relationship exists between a hyperlordotic lumbar spine posture and the level of physical activity, physical activity specifically exercise to strengthen the abdominal muscles should be included in a treatment protocol to reduce the degree of lumbar spine lordosis if the degree is excessive.
26

Sledování příjmu a výdeje energie během redukčních pobytů / Monitoring of energy intake and expenditure during reducing stays

Pražanová, Ivana January 2017 (has links)
Obezita představuje ve vyspělých zemích závažný zdravotní problém a hlavní rizikový faktor rozvoje kardiovaskulárních onemocnění, cukrovky 2. typu, nemocí pohybového aparátu a některých nádorových onemocnění. Je také provázena řadou komplikací a výrazně zhoršuje kvalitu života. 27 pacientů, kteří byli hospitalizováni za účelem redukce hmotnosti na oddělení D3 III. interní kliniky Všeobecné fakultní nemocnice v Praze v období ledna až počátku dubna roku 2017 byli sledováni z hlediska výskytu komorbidit a příjmu a výdeje energie za použití aplikace kaloricketabulky.cz, portálu casprozdravi.cz a krokoměrů Garmin Vivofit. Byla hodnocena vhodnost bioimpedanční metody pro sledování změn složení těla pacientů během redukčních pobytů za použití přístroje InBody S10. V souladu s teorií se ve sledované skupině pacientů vyskytovala v důsledku extrémní obezity celá řada komplikací. Diagnostická kritéria pro metabolický syndrom splňovalo 23 (85%) pacientů. Rozdílné hodnoty obsahu energie a jednotlivých živin v aplikacích kaloricketabulky.cz a Nutriservis jsou příčinou průměrného denního rozdílu 717 kJ mezi záznamy pacientů a nemocničním rozpisem. Průměrně pacienti ušli denně 4713 kroků. Pacienti průměrně zredukovali hmotnost o 7,6 kg (SD ±3,54). Bioimpedanční metoda vykazuje příliš vysokou variabilitu a není...
27

Early Changes of Abdominal Adiposity Detected with Weekly Dual Bioelectrical Impedance Analysis during Calorie Restriction / 毎週の経時的なデュアル生体インピーダンス解析により検出されるカロリー制限時の腹腔内脂肪蓄積の変化の早期把握

Ida, Midori 25 November 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18646号 / 医博第3945号 / 新制||医||1006(附属図書館) / 31560 / 京都大学大学院医学研究科医学専攻 / (主査)教授 川上 浩司, 教授 横出 正之, 教授 千葉 勉 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
28

Effects of monthly feedback of VFA measured by dual BIA method in Japanese patients with obesity: a randomized controlled study / 日本人肥満症患者におけるdual BIA法により測定された内臓脂肪面積の毎月のフィードバックの効果:ランダム化比較試験

Moriyasu, Tomoko 23 July 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第21304号 / 人健博第60号 / 新制||人健||5(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 古田 真里枝, 教授 藤井 康友, 教授 横出 正之 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DGAM
29

Distribuce tukové tkáně u dětí předškolního věku - srovnávací studie / Adipose tissue distribution by preschool children- comparative study

Petrů, Dominika January 2014 (has links)
CHARLES UNIVERSITY IN PRAGUE FACULTY OF PHYSICAL EDUCATION AND SPORT ADIPOSE TISSUE DISTRIBUTION BY PRESCHOOL CHILDREN- COMAPARATIVE STUDY ABSTRACT Head of the dissertation: Author: Prof. MUDr. Ivan Dylevský, DrSc. Mgr. Dominika Petrů Prague, 2014 Abstract The dissertation provides information about the distribution of subcutaneous adipose tissue in preschool-aged /5-6 years, n=141/ and younger school-aged children /8- 9 years, n=137/ in the Ústí region. In this review, we describe and evaluate the child's body with anthropometric parameters, skinfold, bioelectrical impedance analysis and selected sample /n=31/ with ultrasonography. We found an increased distribution of adipose tissue in older file with a concentration in the abdominal area and a higher reliability of skinfold than the BIA, considering the ultrasound examination. Key words: subcutaneous fat, skinfold, bioelectrical impedance analysis, ultrasonography
30

OBJECTIVE AND SUBJECTIVE MEASUREMENTS OF NORMAL AND OVER HYDRATION

STEPINSKI, JOY DIANA 11 October 2001 (has links)
No description available.

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