Active, Small-Scale, Periglacial Features on the South Coast of Newfoundland

Small-scale, patterned ground is currently forming on the south coast of Newfoundland. Small, sorted circles and stripes form in the vicinity of the coast under the influence of marine climate with numerous, short duration, freeze-thaw cycles, high humidity, abundant rainfall and a thin snow cover throughout the winter, inland, no more than 15 to 25 km from the coast, the marine influence has decreased sufficiently that the patterned ground is no longer forming.On trouve présentement des sols structurés à petite échelle en formation sur la côte sud de Terre-Neuve. De petits cercles et des traînées minérales se développent près de la côte sous l'influence du climat maritime, caractérisé par plusieurs cycles de gel-dégel, une humidité relative élevée, des pluies abondantes et une mince couverture de neige, pendant l'hiver. À l'intérieur des terres, à 15-25 km de la côte tout au plus, l'influence maritime est suffisamment amoindrie pour qu'il n'y ait plus formation de sols structurés

Strong-field approximation for Coulomb explosion of H_2^+ by short intense laser pulses

We present a simple quantum mechanical model to describe Coulomb explosion of H$_2^+$ by short, intense, infrared laser pulses. The model is based on the length gauge version of the molecular strong-field approximation and is valid for pulses shorter than 50 fs where the process of dissociation prior to ionization is negligible. The results are compared with recent experimental results for the proton energy spectrum [I. Ben-Itzhak et al., Phys. Rev. Lett. 95, 073002 (2005), B. D. Esry et al., Phys. Rev. Lett. 97, 013003 (2006)]. The predictions of the model reproduce the profile of the spectrum although the peak energy is slightly lower than the observations. For comparison, we also present results obtained by two different tunneling models for this process.Comment: 8 pages, 4 figure

Raised Shoreline Phenomena and Postglacial Emergence in South-Central Newfoundland

Two types of raised marine shoreline features occur in the Burin-Hermitage area of southern Newfoundland marine benches cut in bedrock, and terraces and beaches developed in unconsolidated materials. Most of the benches are older than Late Wisconsinan, and a horizontal rock shoreline at 4.5 ± 1.5 m, which occurs throughout the region, was probably formed in the last interglacial period. Raised deltas and coastal outwash deposits graded to former sea level positions, which define the Late Wisconsinan marine limit across the northern part of the study area, are correlated with terraces and raised beaches further south on the Burin Peninsula. The elevations of these features are used to define the regional pattern of postglacial emergence. More than 30 m of emergence has occurred in the northwest, but the extreme southern part of the region is undergoing submergence.Dans la région de Burin-Hermitage, au sud de Terre-Neuve, on retrouve deux types de lignes de rivage marines soulevées: des plates-formes marines entaillées dans la roche en place ainsi que des terrasses et des plages développées dans des matériaux meubles. La plupart des plates-formes datent d'avant le Wisconsinien inférieur. Une ligne de rivage rocheuse horizontale située à 4,5 ± 1,5 m, qu'on retrouve à travers la région, fut probablement formée au cours du dernier interglaciaire. Des deltas soulevés et des épandages fluvioglaciaires côtiers, associés à des plans d'eau marins qui marquent la limite marine du Wisconsinien inférieur dans la partie nord de la zone d'étude, sont mis en relation avec des terrasses et des plages soulevées existant plus au sud dans la péninsule de Burin. L'altitude de ces formes sert à établir le mode régional d'émersion post-glaciaire. Il s'est produit une emersion de plus de 30 m dans le nord-ouest, alors que l'extrême-sud de la région est en phase de submersion

Relationships Between Injury-Related Fear, Balance Self-Efficacy, and Dynamic Balance Performance in Those With Chronic Ankle Instability

Interactions between sensory-perceptual and motor-behavioral impairments in individuals with chronic ankle instability (CAI) are important for successful assessment and treatment of CAI. One of the most consistently reported motor-behavioral impairments is poor reach performance in a dynamic balance task. Injury-related fear is recognized as an important sensory-perceptual impairment, and those with injury-related fears may engage in protective movement strategies found to be associated with reach deficits. Injury-related fear may also impact one’s perception of ability, or self-efficacy, which has demonstrated positive associations with balance performance in other populations, but these relationships have yet to be investigated in the CAI population. Objective: To examine the relationships between injury-related fear, self-efficacy, and dynamic balance performance in those with CAI. Methods: 33 individuals with CAI (F:18, M:15, 22.8±3.3yrs, 170.2±8.5cm, 78.0±13.6kg) reported their level of injury-related fear via the Tampa Scale of Kinesiophobia (TSK-11). The Self-Efficacy of Balance Scale (SEBS) was utilized to capture participants’ level of balance self-efficacy. Dynamic balance performance was assessed on the involved limb with the Star-Excursion Balance Test in the anterior, posteromedial (SEBT-PM), and posterolateral (SEBT-PL) directions and a composite (SEBT-COMP) score was calculated for overall performance. Pearson correlations were used to analyze associations between these outcomes with significance set at P PResults: Significant negative correlations were identified between TSK-11 and SEBS scores (r=-0.34, P=0.050), indicating those with higher levels of kinesiophobia demonstrated lower levels of balance self-efficacy. Significant positive correlations were identified between SEBS scores and SEBT-COMP (r=0.48, P=0.005), SEBT-PM (r=0.42, P=0.016), and SEBT-PL (r=0.48, P=0.005), indicating that individuals who perceived themselves as more confident in their balance ability demonstrated better balance performance. Conclusions: Injury-related fear did not have a direct relationship with dynamic reach performance in individuals with CAI, but may have an indirect relationship with dynamic balance performance by impacting one’s balance self-efficacy.https://digitalcommons.odu.edu/gradposters2020_healthsciences/1004/thumbnail.jp

Statistical model of dephasing in mesoscopic devices introduced in the scattering matrix formalism

We propose a phenomenological model of dephasing in mesoscopic transport, based on the introduction of random phase fluctuations in the computation of the scattering matrix of the system. A Monte Carlo averaging procedure allows us to extract electrical and microscopic device properties. We show that, in this picture, scattering matrix properties enforced by current conservation and time reversal invariance still hold. In order to assess the validity of the proposed approach, we present simulations of conductance and magnetoconductance of Aharonov-Bohm rings that reproduce the behavior observed in experiments, in particular as far as aspects related to decoherence are concerned.Comment: 6 pages, 6 figure

Remarks on the KLS conjecture and Hardy-type inequalities

We generalize the classical Hardy and Faber-Krahn inequalities to arbitrary functions on a convex body $\Omega \subset \mathbb{R}^n$, not necessarily vanishing on the boundary $\partial \Omega$. This reduces the study of the Neumann Poincar\'e constant on $\Omega$ to that of the cone and Lebesgue measures on $\partial \Omega$; these may be bounded via the curvature of $\partial \Omega$. A second reduction is obtained to the class of harmonic functions on $\Omega$. We also study the relation between the Poincar\'e constant of a log-concave measure $\mu$ and its associated K. Ball body $K_\mu$. In particular, we obtain a simple proof of a conjecture of Kannan--Lov\'asz--Simonovits for unit-balls of $\ell^n_p$, originally due to Sodin and Lata{\l}a--Wojtaszczyk.Comment: 18 pages. Numbering of propositions, theorems, etc.. as appeared in final form in GAFA seminar note