Variability in daily relationship satisfaction has been shown to undermine future relationship well-being. The current study suggests that the relationship climate may moderate this effect. Namely, and in light of prior work showing that ignoring relationship issues can be detrimental for long-term relationship well-being, it is argued that when the relationship is characterized by more negative relationship experiences, variability in daily satisfaction may actually represent an adaptive acknowledgement of those experiences. Seventy-eight newly-married couples completed a 10-day daily diary task which assessed the variability of daily marital satisfaction, the positive and negative marital events taking place each day, and the daily coping strategies used to manage negative marital events. Spouses then reported on their global marital happiness as well as the severity of their marital problems every six months over the first two and a half years of marriage. Results revealed that when the marriage was characterized by more negative than positive marital events (i.e., a more negative marital climate), greater variability in daily satisfaction predicted initially lower levels of global marital happiness and more severe marital problems. However, greater variability in a more negative marital climate also was associated with less steep declines in global marital happiness and fewer increases in marital problems over time compared to low variability. Together, these findings suggest that variability in daily relationship satisfaction may temporarily feel unpleasant but over time may allow couples to address important relationship issues. / text

Monthly and annual changes in precipitation in South China during 1990-2011 are examined in this study. As located in the sub-tropical climate zone, the annual rainfall in South China is concentrated in the summer. During the same period of time, an average of 9 tropical cyclones approaching South China each year which also contribute ample of rainfall to South China during the tropical cyclone season (June-September). Since the climatic system is interconnected, so this study attempts to examine the combined effect on inter annual rainfall variations in South China due to El Nino Southern Oscillation (ENSO), tropical cyclones affecting South China and the Asian Monsoon. It is generally agreed that during the El Nino onset years, South China would be more wetter, but with less than average tropical cyclones affecting South China. As such, effects on precipitation in South China caused by these two factors offsetting each other and data indicate there is no consistent trend of either more or less rainfall recorded for the El Nino onset years during 1990-2011. On the other hand, the first half of the year right after the El Nino years are in general more wetter than normal. This can be due to the lagging effect of El Nino events normally happened in the winter time, plus the fact that the strength of winter monsoon during the El Nino years is weak, resulting in more rainfall in the following year. Furthermore, annual changes in precipitation in South China directly affect the surface runoff of the Pearl River and a strong positive correlation between the two variables exists for the period 2000-2011. The +/- 25% annual variations and the seasonal variations of rainfall in South China post a challenge to the water resource management in the Pearl River Delta Region. Therefore dams and reservoirs built along the Pearl River are necessary to store surplus rainwater in order to supply sufficient fresh water to the Pearl River Delta Region during the dry seasons or years. On the other hand, further studies and monitoring programs are recommended to continue assessing and evaluating impacts of dam constructions to the environment and the ecosystem of the Pearl River Delta Region. / published_or_final_version / Applied Geosciences / Master / Master of Science

Precipitation patterns in semi-arid river systems of the southwestern U.S. make stream-aquifer exchanges an important source of water in perennial rivers. Nonetheless, the spatial and temporal evolution of surface and ground water interaction are not fully understood. This research utilizes diurnal temperature oscillations as a tracer of vertical water fluxes by applying Stallman's analytical solution to a series of temperature time series recorded in the stream and in the streambed of the San Pedro River. Temperature measurements were recorded at four spatial extents using a nested hierarchy during four different periods since last flood. Time since last flood did not affect vertical fluxes significantly, but fluxes exhibited spatial dependence at lengths of 6-24 m. Stream geomorphic features influenced the magnitude of vertical fluxes; runs were more downwelling than riffles. The data suggests that the spatial distribution of vertical fluxes becomes more homogeneous as time since last flood increases.

Grip kinetics are emerging as an important measure in clinical assessments of handwriting pathologies and fine motor rehabilitation as well as in biometric and forensic applications. The signature verification literature in particular has extensively examined the spatiotemporal, kinematic, and axial pressure characteristics of handwriting, but has minimally considered grip kinetics. Therefore, the focus of this thesis was to investigate the variability of grip kinetics in adults during signature writing. To address this goal, a database of authentic and well-practiced bogus signatures were collected with an instrumented pen that recorded the forces applied to its barrel. Four different analytical studies were conceived. The first study investigated the intra- and inter-participant variability of grip kinetic topography on the pen barrel based on authentic signatures written over 10 days. The main findings were that participants possessed unique grip force topographies even when the same grasp pattern was employed and that participants could be discriminated from each other with an average error rate of 1.2% on the basis of their grip force topographies. The second study examined the stability of different grip kinetic features over an extended period of a few months. The analyses revealed that intra-participant variation was generally much smaller than inter-participant variations even in the long term. In the third study, grip kinetics associated with authentic and well-practiced bogus signatures were compared. Differences in grip kinetic features between authentic and bogus signatures were only observed in a few participants. The kinetics of bogus signatures were not necessarily more variable. The variation of grip kinetic profiles between participants writing the same bogus signature was evaluated in the fourth study and an average error rate of 5.8% was achieved when verifying signatures with kinetic profile-based features. Collectively, the findings of this thesis serve to inform future applications of grip kinetic measures in biometric, clinical and industrial applications.

Grip kinetics are emerging as an important measure in clinical assessments of handwriting pathologies and fine motor rehabilitation as well as in biometric and forensic applications. The signature verification literature in particular has extensively examined the spatiotemporal, kinematic, and axial pressure characteristics of handwriting, but has minimally considered grip kinetics. Therefore, the focus of this thesis was to investigate the variability of grip kinetics in adults during signature writing. To address this goal, a database of authentic and well-practiced bogus signatures were collected with an instrumented pen that recorded the forces applied to its barrel. Four different analytical studies were conceived. The first study investigated the intra- and inter-participant variability of grip kinetic topography on the pen barrel based on authentic signatures written over 10 days. The main findings were that participants possessed unique grip force topographies even when the same grasp pattern was employed and that participants could be discriminated from each other with an average error rate of 1.2% on the basis of their grip force topographies. The second study examined the stability of different grip kinetic features over an extended period of a few months. The analyses revealed that intra-participant variation was generally much smaller than inter-participant variations even in the long term. In the third study, grip kinetics associated with authentic and well-practiced bogus signatures were compared. Differences in grip kinetic features between authentic and bogus signatures were only observed in a few participants. The kinetics of bogus signatures were not necessarily more variable. The variation of grip kinetic profiles between participants writing the same bogus signature was evaluated in the fourth study and an average error rate of 5.8% was achieved when verifying signatures with kinetic profile-based features. Collectively, the findings of this thesis serve to inform future applications of grip kinetic measures in biometric, clinical and industrial applications.

Introduction Many chiropractic articles and textbooks discuss gait, but there actually has been little research into the effects of chiropractic adjustment on gait. This pilot study used a quantitative method of gait evaluation before and after a series of chiropractic visits. Hypotheses: (1) adults with chronic low back pain (CLBP) would show increased variability in vertical ground reaction forces (VGRF) while walking, as compared to healthy control subjects, and (2) that, following chiropractic care, will show decreased variability. Methods VGRF data were collected for 6 controls and compared to 9 CLBP participants, who were also evaluated before and after the first visit of care and over 7 visits. Data were analyzed by Mean Standard Deviation (MSD), Mean Coefficient of Variation (MCV), and the Coefficient of Variation of loading rate. Chiropractic care consisted of “high velocity low amplitude” thrust type procedures, flexion-distraction, pelvic wedges, light mobilization, and stretching. Results CLBP participants had somewhat greater variability and became slightly less variable post-care; differences were not significant. Limitations: Some participants had no impairment of walking at baseline; MSD is an uncommon measure, and more research is needed; these results (small group seen by a single doctor) may not be generalizable. Conclusions Participants with CLBP had slightly more variability and had slight decreases in variability following chiropractic care. Differences were not statistically significant. With this small pilot study as a guide, more research should be done with larger groups and improved participant selection.

Cognitive deficits are highly prevalent in multiple sclerosis (MS) and have a negative impact on daily life. Impairments in information processing speed are among the most commonly reported deficits in MS and are generally assessed by evaluating mean-level performance on time-limited tests. However, this approach to assessing performance ignores potential within-subject differences that may be useful for characterizing cognitive difficulties in MS. An alternative method of measuring performance on timed cognitive tasks is to examine the degree of within-subject variability, termed intraindividual variability (IIV). IIV provides information about the characteristics of an individual’s performance and may provide novel information about cognitive functioning in MS and other neurodegenerative disorders. The research presented in this dissertation examined IIV in performance as an indicator of cognitive functioning in persons with MS and explored the relations of performance variability to measures of neuronal connectivity derived from resting state functional magnetic resonance imaging (rsfMRI). Individuals with MS were found to be both slower and more variable on tests of information processing speed and attention. This variability was observed even when controlling for sensorimotor confounds and other systematic variables that may influence variability, such as practice and learning effects. IIV in performance was found to better distinguish MS patients from matched groups of healthy control subjects when compared to common clinical measures of cognitive performance or average response speed. These differences in IIV were also found consistently across six monthly assessments in a group with MS who remained clinically stable over this period. This stability in IIV suggests its feasibility as a measure of changes in longitudinal cognitive or clinical status. Using rsfMRI, greater stability in performance (i.e., lower IIV) was associated with greater functional connectivity between frontal lobe regions (i.e., ventral medial prefrontal cortex and frontal pole) in persons with MS. This increased connectivity appears to represent potential compensatory processes within mildly affected MS individuals. Together the findings demonstrate that IIV is an important characteristic of cognitive performance that may provide new insights into the cognitive deficits present in MS.

Economic research on climate and productivity effects of ocean phenomena has mostly focused on interannual cases such as the El Niño Southern Oscillation. Here Decadal climate variability (DCV) refers to ocean related climate influences of duration from seven to twenty years. The specific phenomena analyzed here are the Pacific Decadal Oscillation, the Tropical Atlantic Gradient and the West Pacific Warm Pool. Their positive and negative phases, occurring individually or in combination, are associated with variations in crop and water yields. This dissertation examines the value of DCV information to agriculture and water users in the Missouri river basin using a price endogenous agricultural and non-agricultural model that depicts cropping and water use. The model is used to evaluate the welfare gains and adaptations given various levels of DCV information. The analysis shows the value (for a 10-year average) for a perfect forecast is about 5.2 billion dollars, though 86% of this value, 4.55 billion dollars, can be obtained by a less perfect forecast based on already available data in the form of the prediction of DCV phase under transition probabilities. The results indicate that forecasting any DCV state is important because of differential responses in the acreage of major crops plus water use adjustments by residential, agricultural and industrial users.

In patients with normal hearts, increased vagal tone is associated with the onset of paroxysmal atrial fibrillation (AF). Vagal denervation of the atria renders AF less inducible. Circumferential pulmonary vein ablation (CPVA), with or without isolation (CPVI), is effective for treating paroxysmal AF, and has been shown to impact HRV indices, in turn reflecting vagal denervation. We examined the impact of CPVI on HRV indices over time, and evaluated the relationship between vagal modification and rate of recurrence of AF. High resolution ECG recordings were collected from 64 patients (49 male, 15 female, mean age 57.1±9.7) undergoing CPVI for paroxysmal (n=46) or persistent (n=18) AF. Recordings were made pre-procedure, and at intervals up to 12 months. Success was defined as no recurrence. After CPVI, 27 patients presented recurrence. Pre-procedure HRV variables did not differ from controls in patients with a subsequent successful procedure. However, patients with recurrence demonstrated significantly-reduced pre-procedure HRV compared both with controls, and with patients having successful procedures (39.6±23.4 & 33.7±19.2 vs 21.8±11.8, P =0.01 & P=0.04). Following the procedure, HRV was reduced vs pre-procedure in patients with successful procedures (33.7±19.2 vs 18.6±15.8, P=0.01), and did not differ from unsuccessful procedures over a 12 month FU. Both groups were reduced compared with a control value. There was no significant difference in HRV between patients who experienced recurring AF (n=9), and those who experienced AT or flutter (n=18). Our data suggests that patients experiencing recurrence after one procedure have reduced HRV that is not changed by CPVI; whereas patients with a successful single procedure experience a change in HRV variables that is sustained over a long period, but is no different post-procedure from patients experiencing recurrence. These data suggest that denervation associated with CPVI may benefit patients with normal vagal tone prior to the procedure, but that sustained denervation is not a critical factor in successful outcome after CPVI. / Thesis (Master, Computing) -- Queen's University, 2010-12-07 08:32:15.066

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