• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 54
  • 20
  • 9
  • 7
  • 6
  • 3
  • 1
  • Tagged with
  • 129
  • 129
  • 46
  • 25
  • 22
  • 22
  • 21
  • 16
  • 16
  • 15
  • 14
  • 14
  • 13
  • 13
  • 12
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Reproduction and Metabolic Responses to Acute and Chronic Hypoxia in Ovoviviparous Blaberid Cockroaches, with a Focus on Blaptica dubia

Mallery, Christopher Sean 08 1900 (has links)
The major components of the tracheal system of insects are an extension of the exoskeleton, and the size of the exoskeleton is fixed in the adult stage, so any increase in metabolic demand that may accompany reproduction must be met by a relatively unaltered tracheal system that the female set in place at ecdysis, when entering adulthood. Acute hypoxia tends to elicit an increase in ventilation in insects, and here, I observe increased interburst VCO2 release, and a tendency towards a more continuous gas exchange pattern being preferred over discontinuous gas exchange when Blaptica dubia and Eublaberus posticus are exposed to a descending regime of hypoxia. Additionally, higher temperatures appear to increase sensitivity to hypoxia in these species, an expected result because both species, like most ectothermic animals, display a Q10 effect, increasing metabolic rates as temperature increases. The reproductive mode of B. dubia is considered to be lecithotrophic pseudoviviparity (or type A ovoviviparity), and by the time the embryos are born, they have more than doubles in volume from the time of oviposition. This gain is apparent in the wet mass of the embryo, with no change occurring in dry mass. The egg mass that can be attributed to water begins at 39% at oviposition and increased to nearly 82% at hatching. The metabolic rates of females and embryos increase as embryonic development progresses, but bomb calorimetry reveals that energy content of the embryos does not change. It is possible that these embryos gain some nutrition from the mother during embryonic development, but direct evidence remains to be demonstrated. Blaptica dubia and Eublaberus posticusare both blaberid species that display the same reproductive mode, pseudoviviparity, with incubation occurring in a brood sac. Comparisons between the reproductive traits of B. dubia and E. posticus reveal that the two species have similar reproductive periods, interbirth periods, and clutch sizes to one another, and that both have reproductive cycles and incubation times intermediate to oviparous species and the one species of cockroach that some consider to be truly viviparous (Diploptera punctata). However, whereas adult female E. posticus are larger than female B. dubia (E. posticus non-gravid female mass: 2.91 +/- 0.42 g, 20; B. dubia non-gravid female mass: 2.60 +/- 0.40 g, 20), the offspring of B. dubia are larger than those of E. posticus at the time of birth (B. dubia neonate mass: 24.70 +/- 4.01 mg, 19; E. posticus neonate mass: 22.40 +/- 1.36 mg, 19). Both gravid and non-gravid female B. dubia respond similarly to acute hypoxia exposure, increasing mean total VCO2. However, the reproductive state does not appear to exacerbate, nor dull, the acute response to hypoxia. Gravid and non-gravid female B. dubia were exposed to chronic hypoxia for 30 days and 45 days. Relatively high mortality was observed in nearly all chronic hypoxic treatment groups as compared to controls at 21 kPa O2. Comparing treatment groups to controls maintained at 21 kPa O2, embryo mass was not decreased, nor was embryo VCO2 at day 30. Adult female B. dubia metabolic rates did not show a consistent change in response to chronic hypoxia, but decreased metabolic rate was observed in the non-gravid B. dubia exposed to chronic 4 kPa O2, an observation that is consistent with past studies in insects. Survival rates were lower for both gravid and non-gravid females in 4, 8, and 12 kPa O2, as well as in 15 kPa O2 in gravid females, as compared to 21 kPa O2. Gravid females experiences a decreased survival rate compared with non-gravid females at 12 and 15 kPa O2, but gravid and non-gravid females had similarly low survival rates at 4 and 8 kPa O2. This difference in survival rates suggests there is a cost associated with carrying an ootheca in a brood sac, resulting in an increased sensitivity to hypoxia, at least over a long period of time.
62

The role of energy expenditure in roost selection by bats

Marroquin, Cynthia Maria January 2020 (has links)
No description available.
63

Bazální metabolismus, výživová intervence a potraviny způsobující nociceptivní bolest u osob s míšní lézí / Basal metabolic rate, dietary intervention and nutrients producing nociceptive pain in individuals with spinal cord injury

Chaloupková, Eva January 2020 (has links)
Title: Basal metabolism and nutritional intervention for people with spinal cord injuries Objectives: The main objective of this work was empirical research of case evaluation studies (n = 3), where we analyzed: the relationship between energy expenditure (basal metabolism) and energy intake for people diagnosed with spinal cord injury (SCI). The secondary objective was to determine whether the changes in macronutrient distribution and daily energy intake would result in a decrease in body weight and body fat for individual probands. The pilot study in our work was focused on the overview of variable basal metabolism (BM) values for people with SCI. Methods: In our work, we used the method of indirect calorimetry to measure BM and together with the value of working metabolism we determined in the nutritional intervention (n. i.) the ideal energy intake for our probands. We observed primarily measurable changes in the amount of fat and muscle tissue. Results: We have found that, in keeping with the prescribed n. i. rules, all probands achieved to reduce their body weight. The average body weight loss for probands was 0.29 ± 0.02 kg per week. BM values in our pilot study were 15 to 61% lower for our probands (n = 15) and did not correlate with the height of SCI. Key words: spinal cord injury (SCI),...
64

Bazální metabolismus, výživová intervence a potraviny způsobující nociceptivní bolest u osob s míšní lézí / Basal metabolic rate, dietary intervention and nutrients producing nociceptive pain in individuals with spinal cord injury

Chaloupková, Eva January 2020 (has links)
Title: Basal metabolism and nutritional intervention for people with spinal cord injuries Objectives: The main objective of this work was empirical research of case evaluation studies (n = 3), where we analyzed: the relationship between energy expenditure (basal metabolism) and energy intake for people diagnosed with spinal cord injury (SCI). The secondary objective was to determine whether the changes in macronutrient distribution and daily energy intake would result in a decrease in body weight and body fat for individual probands. The pilot study in our work was focused on the overview of variable basal metabolism (BM) values for people with SCI. Methods: In our work, we used the method of indirect calorimetry to measure BM and together with the value of working metabolism we determined in the nutritional intervention (n. i.) the ideal energy intake for our probands. We observed primarily measurable changes in the amount of fat and muscle tissue. Results: We have found that, in keeping with the prescribed n. i. rules, all probands achieved to reduce their body weight. The average body weight loss for probands was 0.29 ± 0.02 kg per week. BM values in our pilot study were 15 to 61% lower for our probands (n = 15) and did not correlate with the height of SCI. Key words: spinal cord injury (SCI),...
65

Effects of a phthalate mixture on Wnt/β-catenin signaling, apoptosis and metabolic rate in zebrafish embryos

Bountis, Stavros January 2020 (has links)
One of the most common plasticizers used in the production of plastic are phthalates. These chemicals have been associated with many adverse effects including developmental and reproductive anomalies. Early developmental processes targeted by chemicals can have long-lasting effects on individuals. The focus of this study was on investigating the effects of a phthalate monoester mixture on two evolutionarily conserved processes, Wnt/β-catenin signaling and apoptosis, both of which play an important role during development. Focus was also given on the mixture’s effect in metabolic rate. The phthalate mixture used is part of mixture G, a mixture which additionally contains triclosan and three perfluoroalkyl acids. The components of Mixture G were identified in a Swedish pregnancy cohort (SELMA) and were inversely associated with birth weight. The experiments were conducted in zebrafish embryos. Wnt signaling was analyzed in a transgenic zebrafish line, which had the EGFP gene linked to β-catenin regulated promoters, by measuring the fluorescence in the caudal fin. Apoptosis was analyzed through the acridine orange assay and metabolic rate through the transformation of resazurin to resorufin in presence of NADH/NADPH. The results showed a downregulation of Wnt signaling in zebrafish at two days post-fertilization (2 dpf), at a water concentration 100 times higher than the geometric mean serum concentration (100x hsc) of the mothers in the SELMA cohort. An upregulation of apoptosis was found at 1 dpf, at 60x hsc and 100x hsc. An effect on metabolic rate was observed at 100x hsc at 5 dpf. The results indicate that phthalates can disrupt Wnt signaling, induce apoptosis and influence metabolic rate, which along with the various reproductive effects they can induce warrants cause for concern not only for zebrafish embryos but for human fetuses as well.
66

Effect of Hypoxia on Metabolic Rate, Core Body Temperature, and C-Fos Expression in the Naked Mole Rat

Nathaniel, Thomas I., Otukonyong, Effiong, Abdellatif, Ahmed, Soyinka, Julius O. 01 October 2012 (has links)
Recent investigations of hypoxia physiology in the naked mole rat have opened up an interesting line of research into the basic physiological and genomic alterations that accompany hypoxia survival. The extent to which such findings connect the effect of hypoxia to metabolic rate (O2 consumption), core body temperature (Tb), and transcripts encoding the immediate early gene product (such as c-fos) under a constant ambient temperature (Ta) is not well known. We investigated this issue in the current study. Our first sets of experiments measured Tb and metabolic rates during exposure of naked mole rats to hypoxia over a constant Ta. Hypoxia significantly decreased metabolic rates in the naked mole rat. Although core Tb also decreased during hypoxia, the effect of hypoxia in suppressing core Tb was not significant. The second series of experiments revealed that c-fos protein and mRNA expression in the hippocampus neurons (CA1) increased in naked mole rats that were repeatedly exposed to 3% O2 for 60min per day for 5 days when compared to normoxia. Our findings provide evidence for the up-regulation of c-fos and suppression of metabolic rate in hypoxia tolerating naked mole rats under constant ambient temperature. Metabolic suppression and c-fos upregulation constitute part of the physiological complex associated with adaptation to hypoxia.
67

Vliv tělesného složení na hodnotu klidového energetického výdeje u obézních pacientů / Effect of body composition on resting metabolic rate in obese patients

Staňová, Alžběta January 2021 (has links)
Introduction: Changes in eating habits and incorporation of physical activities remain to be the main methods in treating obesity. To set an adequate calorie intake, which would lead to weight loss, it is necessary to determine energy needs of an individual. For that energy intake and energy expenditure need to be determinate. However, energy expenditure is difficult to determine since it is contributed of three components. Basal, respectively resting metabolic rate (RMR), which is affected by a body composition, has the greatest influence on a total energy expenditure. Indirect calorimetry (IC) is considered to be a gold standard to determine RMR. When RMR is calculated by prediction equations instead, such as Harris-Benedict (H-B) equation, energy needs are overestimate or underestimate for people with abnormal body composition. Objectives: The aim of this study is to analyse data of RMR obtained using IC in connection to body composition. The main aim is to determine how fat free mas (FFM) and fat mass (FM) are affecting RMR in obese patients. There is also a comparation of RMR measured by the IC and RMR calculated using H-B equation as a part of this study, while IC is considered to be a reference method. Methods: Patients new to ambulance of obesitology at General University Hospital in Prague...
68

The role of thermal niche selection in the maintenance of a colour polymorphism in Plethodon cinereus

Petruzzi, Erin E. 03 August 2005 (has links)
No description available.
69

Reproduction, Energy Budget, and the Sibling Effect in Nine-Banned Armadillo, Dasypus Novemcinctus

Lengyel, Megan S. 13 May 2011 (has links)
No description available.
70

A Comparison of the Effects of Interval Training vs. Continuous Training on Weight Loss and Body Composition in Obese Pre-Menopausal Women.

King, Jeffrey Warren 01 May 2001 (has links) (PDF)
The purpose of this study was to investigate the role exercise intensity plays in reducing body weight and percent body fat in overweight women. Subjects were randomized to either a high intensity interval training group (IT) or a lower intensity steady state training group (ST). Each group exercised 3 times per week for 8 weeks and expended 300 kcal per exercise session. VO2max, body composition, and resting metabolic rate (RMR) were measured pre and post training. RMR was measured after exercise at week 2 to see if intensity levels affected RMR. VO2max and body composition improved in IT but not in ST. Neither group showed a change in RMR from pretest to posttest; however, IT had an increase in RMR 24 hours post-exercise whereas ST did not. These findings show that high intensity interval exercise produces improvements in body composition, fitness, and acute RMR compared to low intensity steady state training.

Page generated in 0.086 seconds