Evidence for the repeated, independent evolution of hot- and cool-season breeding populations across colonies of the Band-rumped Storm-petrel has garnered much interest from seabird ecologists and evolutionary biologists, alike. Sympatric seasonal populations have been shown to be each other’s closest relatives, implying that ecological divergence into two seasonal foraging types has taken place several times independently across the species’ range, each time in the absence of geographical barriers to gene flow. I present data on the molecular genetic characteristics of a unique year-round breeding population in the Cape Verde archipelago. Using mitochondrial control region sequence and five microsatellite loci, I characterized genetic relationships among 220 birds breeding in four different months (January, April, June and November) and tested for a relationship between temporal isolation and genetic differentiation. Birds breeding in April, June and November were genetically indistinguishable at microsatellite loci, but control region sequence suggested differentiation between January and other months (pairwise ΦST from 0.19 to 0.46, p≤0.05). No evidence for genetic isolation by time was found. A comparison of birds breeding in June and November revealed significant differences in a suite of morphological traits related to foraging strategy (tarsus length, bill length, bill depth, head length, wing length and tail shape), and even significant variation among birds breeding in the same month, despite evidence for gene flow between these groups. Interpreting these patterns in the context of Band-rumped Storm-petrel populations range-wide, I suggest that divergent selection on standing variation within ancestral populations may be an important mechanism explaining the repeated, independent evolution of conserved seasonal foraging types in this species. / Thesis (Master, Biology) -- Queen's University, 2011-02-28 12:02:44.256

The resonance of stationary waves in a mid-latitude (beta)-plane model is examined. In a series of linear experiments it is found that a large, quasi-resonant response occurs even in the presence of realistic damping. With forcing of reasonable amplitude the resonant growth rates are found to be such that a period of several weeks is required for the resonant mode to achieve large amplitude in the troposphere. When nonlinear effects are included the growing resonant wave is found to cause a stratospheric warming and zonal wind reversal and thus drives the system off resonance. We therefore examine flow configurations for which the nonlinear terms vanish. It is found that these flow configurations can resemble realistic blocking patterns. When diabatically forced, the resonant growth of these patterns does not give rise to any nonlinear interactions, although such interactions do occur if other models, which do not satisfy the non-interaction conditions, are present. We conclude that resonant growth can lead to the establishment of large-amplitude, stationary, long waves even when realistic damping and non-linear effects are operating.

No description available.

Seeds of many grasses and legumes from the Canadian Prairies have dormancy which prevents the germination of viable seeds in otherwise favorable conditions. Plant-derived smoke can improve germination in dormant seeds. Seeds of eight grasses, two legumes, and Lactuca sativa were investigated for the effects of seed priming in aqueous smoke solutions on germination, seedling emergence, seedling growth, and standing crop. Aqueous smoke solutions were produced by bubbling smoke generated from the incomplete combustion of wheat straw (Triticum aestivum cv. Unity) or prairie hay (Festuca hallii) through distilled water. Seeds were primed for 24 h in darkness using serial dilutions (1/1000v/v, 1/100v/v, 1/10v/v and 1/1v/v) of the aqueous smoke solutions. After priming, seeds were dried at 20°C in darkness for 7d and placed in petri dishes containing filter paper, after which 5 mL of distilled water were applied. Seeds were incubated at 10/0°C or 25/15°C in 12h light/12h darkness or 24 h darkness for 49 d. Seeds were also primed using 1/100v/v aqueous smoke solutions of wheat straw or prairie hay and seeded in the field. Non-primed seeds and those primed in distilled water (0/1v/v) were used as controls. Within species, germination varied significantly (P≤0.05) among concentrations of aqueous solutions of smoke, smoke type, light, temperature, and their interactions. Total germination of Astragalus cicer, Trifolium ambiguum, Hesperostipa comata, Stipa viridula, and Pascopyrum smithii was not changed by priming seeds. Depending on light or temperature treatments, priming seeds of Agropyron dasystachyum, Elymus junceus, Dactylis glomerata, Elymus angustus, and Festuca hallii in aqueous smoke solutions improved germination by 16%, 20%, 32%, 49%, and 50%, respectively. Priming seeds in aqueous smoke solutions reduced the number of days to 50% germination for Trifolium ambiguum, Lactuca sativa, Festuca hallii, and Stipa viridula (2 d), Elymus junceus (3 d), Dactylis glomerata (4 d), Hesperostipa comata (10 d), and Pascopyrum smithii (15 d). Priming seeds in aqueous smoke solutions increased seedling lengths (combined hypocotyl and radicle lengths) for Elymus angustus and Hesperostipa comata by 28% and 100%, respectively, but it reduced seedling lengths of Lactuca sativa, Festuca hallii, and Trifolium ambiguum. Seedlings from seeds primed in aqueous smoke solutions generated from wheat straw were longer for Lactuca sativa (83%), Elymus angustus (52%), and Hesperostipa comata (36%) as compared with prairie hay, respectively. Priming seeds interacted with smoke type to increase seedling lengths for Pascopyrum smithii (92%), Elymus junceus (100%), and Agropyron dasystachyum (100%), but it reduced seedling lengths for Astralagus cicer (26%), Trifolium ambiguum (55%), and Dactylis glomerata (90%). Exposing seeds to aqueous smoke solutions partially substituted a light requirement for germination in Pascopyrum smithii, Festuca hallii, Hesperostipa comata, Dactylis glomerata, Agropyron dasystachyum, Stipa viridula, and Elymus junceus. Priming seeds in aqueous smoke solutions increased standing crop of Dactylis glomerata by 57%, but total seedling emergence and rate of emergence of seedlings in the field were not different (P>0.05) among priming treatments. Priming seeds in aqueous smoke solutions generated from wheat straw or prairie hay can stimulate germination in Agropyron dasystachyum, Dactylis glomerata, Elymus junceus, Elymus angustus, and, Festuca hallii.

This thesis examined Autonomic Nervous System activity evoked by postural instability. Autonomic reactions were assessed using measures of electrodermal activity at the surface of the skin. Perturbation-evoked electrodermal responses (EDRs) were consistently observed in conjunction with both upper and lower limb postural reactions. These autonomic responses were sensitive to perturbation amplitude, as well as experimental manipulations which did not influence the perturbation itself but which affected response execution. In particular, stimulus predictability and movement challenge modulated EDRs, although purely cognitive manipulations did not significantly affect autonomic responses. Probes examining the potential role of such autonomic potentials in compensatory balance control revealed that EDRs evoked during compensatory postural reactions were larger and more consistent than potentials evoked by purely motor or sensory stimuli, suggesting that evoked autonomic activity plays a role in compensatory behavior. While the specific role of autonomic contributions in compensatory balance control require further study, speculative models for autonomic contributions propose either feedback-based pathways for detection of instability to initiate the postural reaction, and/ or an adaptive role to higher centers important for establishing sensorimotor gain in future conditions. This thesis presents new evidence regarding basic neural mechanisms engaged in the recognition and response to postural instability, and future work may extend these findings in clinical populations with high fall incidence and offer clues as to alternative causes for falls and fall prevention.

Recovery of the ability to maintain balance during standing is one of the primary and essential goals of rehabilitation programs for individuals with Spinal Cord Injury (SCI). Regaining functionality during standing by means of a neuroprosthesis would decrease secondary complications and increase independence, and would consequently improve the quality of life of these individuals. However, the development of a standing neuro- prosthesis requires techniques to generate reliable and predictable torque vectors in the lower limbs. We proposed and tested a method based on surface Functional Electrical Stimulation (FES) and the idea that three independent muscles can form a basis that would span the joint torque vector space. We tested the proposed stimulation technique on the quadriceps muscles that produce knee extension. The results of this study suggest that the quadriceps muscle basis vectors are insufficient to cover the knee joint vector space.

Thesis (MAppSc in Physiotherapy) -- University of South Australia, 1993

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 95-98).

No description available.

Dynamic standing balance is essential to perform functional activities and is included in the treatment of many lower extremity injuries. Physiotherapists utilize many methods to restore standing balance including stability exercises, functional retraining, and manual therapy. The purpose of this study was to investigate the effects of a rearfoot distraction manipulation on dynamic standing balance. Twenty healthy participants (age: 24.4 ± 2.8 years; height: 162.9 ± 37.7 cm; mass: 68.0 ± 4.8 kg; right leg dominant = 20) completed this study. Following familiarization, dynamic standing balance was assessed during: (1) an experimental condition immediately following a rearfoot distraction manipulation, and (2) a control condition. Dominant leg balance was quantified using the Y-balance test which measures lower extremity reach distances. Reach distances were normalized to leg length and measured in the anterior, posteromedial and posterolateral directions. Overall balance was calculated through the summing of all normalized directions. Paired t-tests and Wilcoxon rank tests were used to compare balance scores for parametric and non-parametric data as appropriate. Significance was set at 0.05 a priori. Effect size (ES) was calculated to determine the clinical impact of the manipulation. Increased reach distances (indicating improved balance) were noted following manipulation for overall balance (p = 0.03, ES = 0.26) and in the posteromedial direction (p = 0.01, ES = 0.42). Reach distances did not differ for the anterior (p = 0.11, ES = 0.16) or posterolateral (p = 0.11, ES = 0.25) components. Dynamic standing balance improved after a rearfoot distraction manipulation in healthy participants. It is hypothesized that manual therapy applied to the foot and ankle may be beneficial to augment other therapeutic modalities when working with patients to improve dynamic standing balance.