10,907 research outputs found
Energetic Consequences for a Northern, Range-Edge Lizard Population
Lizards at the northern, cool edge of their geographic range in the northern hemisphere should encounter environmental conditions that differ from those living near the core of their range. To better understand how modest climate differences affect lizard energetics, we compared daily feeding and metabolism rates of individual Sceloporus occidentalis in two populations during mid-summer. Chuckanut Beach (CB) was a cool, maritime climate in northern Washington State, and Sondino Ranch (SR) was a warmer, drier climate in southern, inland Washington. We found no difference between populations in daily energy expenditure (DEE), as calculated from doubly labeled water estimates. The CB population, however, had significantly higher prey availability and rate of daily energy intake (DEI) as estimated from fecal pellet masses. Consequently, CB lizards had higher size-adjusted body masses than lizards from SR. Within CB, during midsummer, DEE was similar to DEI. Within the SR population, DEE trended higher than DEI during midsummer, but was not significantly different. We found no population differences in lizard activity, active body temperature, or preferred body temperature. Hence, we infer the longer activity season for the SR population may compensate for the low food availability and high daily energy cost of midsummer. Moreover, for the CB population, we infer that cooler temperatures and higher food availability allow the lizards to compensate for the shorter activity. We also suggest the CB population may benefit from the predicted warmer temperatures associated with climate change given the similar activity-period body temperatures and DEE between these lizard populations assuming food availability is sufficient
Nonlinear actuator disk theory and flow field calculations, including nonuniform loading
Actuator disk theory and flow field calculations for propeller induced flow with nonuniform circulation distributio
The 2p yields 1s pionic transition
Pion-atomic transitions, perturbation theory, S waves, and P wave
Climate, Physiology, and Distributions: The Role of Thermal Physiology in Biological Invasions
Climate is a primary factor influencing species range dynamics, particularly for ectotherms whose body temperature is closely tied to the surrounding conditions. While range shifts of ectotherms are attributed to climate warming, the mechanism driving these shifts are not well understood. Studies in macrophysiology demonstrate that the interaction of climate with thermal physiology plays a key role in determining large-scale spatial and temporal patterns for many temperature-sensitive physiological traits. This work has revealed a clear relationship between thermal tolerance breadth and range size. However, more recent analyses of this relationship demonstrate that thermal tolerance breadth only provides a partial explanation for patterns in range size. Resting metabolism is a trait closely tied to energy balance, a key determinant of species distribution and abundance. At the whole-organism level, resting metabolism represents the energetic cost to fuel the maintenance of biological processes. Variation in this trait is related to climate and has a significant impact on how energy is allocated towards growth and reproduction. The aim of this dissertation was to understand the impact of climate on thermal physiology and species range dynamics using the Spongy moth (Lymantria dispar dispar) as a model system. The chapters of this dissertation addressed three primary questions: (Chapter 1) Do metabolic rate-temperature relationships (MR-T) vary across the invasive Spongy moth range and is that variation related to climate? (Chapter 2) How does MR-T vary with ontogeny? (Chapter 3) How does thermal performance at the cellular level compare to whole-organism performance? In the first chapter, we found that MR-T of third instar Spongy moth larvae showed significant variation among wild populations and this variation followed a latitudinal cline that was significantly related to climate variation. In the second chapter, larval MR-T showed significant variation across the first five instars of the larval stage. However, we found that the third instar was the most temperature-sensitive and showed the largest increase in metabolic rate after accounting for differences in body size among instars. In the third chapter, we found that whole-organism performance of metabolic rate and growth were mismatched at temperatures beyond the thermal optimum for growth and development of Spongy moth larvae. As temperature increased, metabolic rate continued to increase while growth rapidly declined. However, mitochondrial performance matched growth performance at these supraoptimal temperatures. Furthermore, this response of MR-T, growth, and mitochondrial performance was consistent across five Spongy moth populations. These results produced three primary conclusions. First, the latitudinal variation in whole-organism MR-T among Spongy moth populations was consistent with a pattern of thermal adaptation to divergent climates and suggests that Spongy moth populations have evolved in response to climate as they have spread and expanded their invasive range. Second, the thermal physiology of Spongy moth show significant variation during ontogeny. However, while MR-T does change with instar, our findings suggest it would not alter the conclusions of chapter 1 which is based on the third instar. Finally, the mismatch of MR-T with growth and mitochondrial performance follows the predictions made by the mitochondrial efficiency hypothesis which posits that changes in mitochondrial coupling efficiency is a key mechanism for reducing ectotherm performance. These provide strong evidence for a temperature-dependent link between mitochondria and whole-organism performance. The implications of these findings for the Spongy moth invasion, species range dynamics, and ectotherm performance are discussed further in each chapter
Connecting to the Feminine and to the Inner Self in Sarah Orne Jewett\u27s \u3cem\u3eThe Country of the Pointed Firs\u3c/em\u3e.
In Dunnet Landing, Jewett creates a feminine world that is characterized by its depth and its moral and emotional significance. There is a foundation in the real world of human feeling, and while there is much grief and sorrow in this community, there are also possibilities for happiness. The connection to death and loss is what gives much in this feminine world meaning. Grief is only a part of the journey. Out of death and sorrow come strength and a restoration to wholeness. Mrs. Todd has learned this and she passes her knowledge down to the narrator. The narrator’s journey is a return to a simpler, older way of life. It is a return to the mother, but it is also a return to self, an inversion of a trip to the frontier. The narrator’s connection to Mrs. Todd and Mrs. Blackett helps her to reconnect with and restore herself
A Study of Constant Voltage Anemometry Frequency Response
The development of the constant voltage anemometer (CVA) for the boundary layer data system (BLDS) has been motivated by a need for the explicit autonomous measurement of velocity fluctuations in the boundary layer. The frequency response of a sensor operated by CVA has been studied analytically and experimentally. The thermal lag of the sensor is quantified by a time constant, MCVA. When the time constant is decreased, the half-amplitude cut-off frequency, fCVA, is increased, thereby decreasing the amount of attenuation during measurements. In this thesis, three main approaches have been outlined in theory and tested experimentally to determine the feasibility and effectiveness of implementing them with CVA to limit attenuation: operation at higher Vw, implementation of software compensation, and utilization of smaller diameter sensors. Operation of CVA at higher voltage results in little improvement in frequency response but is accompanied by increased danger of wire burnout. However, sensors do need to be operated at high wire voltages to be more sensitive to velocity fluctuations and less sensitive to temperature fluctuations, without reaching a temperature high enough for wire burnout. Software compensation of the CVA output has been shown not to be useful for measurements with BLDS. The electrical noise present in the CVA measurement system is amplified by the correction algorithm and creates measurements that are not representative of the fluctuations being measured. Decreasing sensor diameter leads to a significant decrease of MCVA and therefore increase of fCVA. Under similar operating conditions, a 2.5 micron diameter sensor showed less roll off in the frequency spectra (measured higher turbulence intensities) than a 3.8 micron diameter sensor for tests in both a turbulent jet and in a turbulent boundary layer. Smaller sensors are more fragile and have been shown to have a decrease in sensitivity as compared to larger sensors; however, for some applications, the increase in frequency response may be worth the trade-off with fragility and sensitivity
Personality Pathology, Health-related Stress, and General Functioning in Later Adulthood
Personality disorders: PDs) are associated with many negative health outcomes, including overutilization of health care resources, increased risk for chronic health problems, and poor adherence to medical recommendations. It is unclear, however, how significantly personality pathology affects an individual\u27s daily health and functioning when health problems have already occurred. The purpose of this dissertation was to determine whether the presence of PD features moderate individual change over time in physical, emotional, and social functioning among individuals with significant health problems. The sample included 1,630 community-dwelling participants, ages 55-64. PD features were measured at baseline; health problems and all outcome variables were measured at baseline and four follow-up assessments. Multilevel modeling analyses were used to test the interactions between number of health problems, time, and personality disorder features in predicting physical, psychological, and social functioning. The results showed that PD features had a significant effect on functioning above and beyond the effects of health problems alone. Borderline, avoidant, and dependent PD features, in particular, showed significant main effects for all three functional outcome domains. Interaction effects with personality pathology were significant for medication use, medical resource utilization, and depressed mood. Individuals with borderline pathology showed significantly more medication use over the 2.5 years when health problems were not present. Individuals with avoidant features used more medical resources over time when health problems were present. Furthermore, individuals with antisocial or histrionic PD features and a higher number of health problems showed increased depressive mood scores over time
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