Towards a Lattice Calculation of the Nucleon Structure Functions

We have initiated a programme to compute the lower moments of the unpolarised and polarised deep inelastic structure functions of the nucleon in the quenched approximation. We review our progress to date.Comment: One author missed out in heplat title. Paper unchanged. 9 pages, uuencoded compress postscript, contributed talk to LAT9

The Most Massive Black Holes in the Universe: Effects of Mergers in Massive Galaxy Clusters

Recent observations support the idea that nuclear black holes grew by gas accretion while shining as luminous quasars at high redshift, and they establish a relation of the black hole mass with the host galaxy's spheroidal stellar system. We develop an analytic model to calculate the expected impact of mergers on the masses of black holes in massive clusters of galaxies. We use the extended Press-Schechter formalism to generate Monte Carlo merger histories of halos with a mass 10^{15} h^{-1} Msun. We assume that the black hole mass function at z=2 is similar to that inferred from observations at z=0 (since quasar activity declines markedly at z<2), and we assign black holes to the progenitor halos assuming a monotonic relation between halo mass and black hole mass. We follow the dynamical evolution of subhalos within larger halos, allowing for tidal stripping, the loss of orbital energy by dynamical friction, and random orbital perturbations in gravitational encounters with subhalos, and we assume that mergers of subhalos are followed by mergers of their central black holes. Our analytic model reproduces numerical estimates of the subhalo mass function. We find that the most massive black holes in massive clusters typically grow by a factor ~ 2 by mergers after gas accretion has stopped. In our ten realizations of 10^{15} h^{-1} Msun clusters, the highest initial (z=2) black hole masses are 5-7 x 10^9 Msun, but four of the clusters contain black holes in the range 1-1.5 x 10^{10} Msun at z=0. Satellite galaxies may host black holes whose mass is comparable to, or even greater than, that of the central galaxy. Thus, black hole mergers can significantly extend the very high end of the black hole mass function.Comment: 13 pages, 7 figures, accepted for publication in The Astrophysical Journa

Dynamical Balance in the Indonesian Seas Circulation

A high resolution, four-open port, non-linear, barotropic ocean model (2D POM) is used to analyze the Indonesian Seas circulation. Both local and overall momentum balances are studied. It is shown that geostrophy holds over most of the area and that the Pacific-Indian Ocean pressure difference is essentially balanced by the resultant of pressure forces acting on the bottom

Translation of EphB2 in PKCgamma and Calretinin Interneuron Subpopulations After Spinal Cord Injury

Introduction: Neuropathic pain is a common, debilitating occurrence after spinal cord injury (SCI). EphB signaling has been implicated in neuropathic pain, but different populations of neurons that upregulate EphB after SCI must be discovered. Understanding whether EphB2 is upregulated in specific subpopulations of dorsal horn interneurons (e.g. those expressing PKCgamma or calretinin) after injury would increase the understanding of SCI-induced neuropathic pain. Methods: Mice were either given a contusion-type SCI (n=7) or a laminectomy-only (n=6) at cervical level 5/6. After two weeks of recovery, mRNA was labeled using RNAscope in the sectioned spinal cords. Four different targets were visualized in the sections via confocal microscopy: nuclei, PKCgamma mRNA, calretinin mRNA, and EphB2 mRNA. Results: An average of 6.15 EphB2 mRNA transcripts were visible per PKCgamma positive interneuron in mice with SCI compared to an average of 5.38 in the laminectomy-only controls. These results were not significantly different using a Student’s t-test (p-value = 0.28). As for calretinin expressing interneurons, an average of 5.15 EphB2 transcripts were present in mice with SCI while an average of 4.83 transcripts were present in the laminectomy-only control group. Again, these results were not significantly different (p-value = 0.24). Discussion: Given our results, it is unlikely that an increase in EphB2 expression in PKCgamma or calretinin expressing interneurons is involved in the development of neuropathic pain after SCI. To find mechanisms underlying SCI-induced neuropathic pain, future studies could examine EphB2 upregulation in different populations of interneurons

Motor Performance and Quality of Life in a Community Exercise Program for Parkinson Disease

We investigated the effect of a comprehensive community program composed of exercise, mindfulness practice, and education on motor function and quality of life in individuals with Parkinson disease (PD). Thirty-six participants completed physical and quality-of-life assessments independently at baseline and 12 months. Physical assessments showed stability or improvement in functional mobility, integrated strength, and walking ability over the 1-year interval. PDQ-39 measures showed improvement in 6 of 8 indices: mobility, activities of daily living, emotional well-being, stigma reduction, social support, and bodily discomfort. Our results demonstrate the effectiveness of exercise, mindfulness, and education in community and group settings

Structural phase transitions in the Ag2Nb4O11 – Na2Nb4O11 solid solution

The phase transitions between various structural modifications of the natrotantite-structured system xAg2Nb4O11 – (1-x)Na2Nb4O11 have been investigated and a phase diagram constructed as a function of temperature and composition. This shows three separate phase transition types: (1) paraelectric – ferroelectric, (2) rhombohedral – monoclinic and (3) a phase transition within the ferroelectric rhombohedral zone between space groups R3c and R3. The parent structure for the entire series has space group R-3c. Compositions with x > 0.75 are rhombohedral at all temperatures whereas compositions with x < 0.75 are all monoclinic at room temperature and below. At x = 0.75, rhombohedral and monoclinic phases coexist with the phase boundary below room temperature being virtually temperature-independent. The ferroelectric phase boundary extends into the monoclinic phase field. No evidence was found for the R3–R3c phase boundary extending into the monoclinic phase field and it is concluded that a triple point is formed

The Effects Of Caffeine On Early Second Half Sprint Performance In NCAA DIII Women’s Soccer Players

Objective The purpose of this study was to examine the effects of caffeine on early second half sprint performance in 21 NCAA DIII women’s soccer players. The caffeine dosage attempted to approximate a liquid dosage many student athletes typically consume. Design In a randomized double blind repeated measures design, subjects began the protocol after ingestion of caplets containing 3 mg.kg-1 of caffeine (CAF) and after ingestion of placebo (PLA) caplets. Pre-game, warm-up, and first half conditions were designed to maximize external validity. Methods An adapted version of the Loughborough Intermittent Shuttle Test was applied to replicate first half activity. Sprint performance was measured with the Running Based Anaerobic Sprint Test. Mean power, maximum power, and minimum power, were assessed under each condition. Repeated measures MANOVA was used to determine if there were significant mean vector differences between the trials. Results Although mean, maximum, and minimum power in the CAF trial increased 3.2%, 3.4%, and 4% respectively, MANOVA results showed no statistically significant differences in the mean vector for power variables (Λ = .752, p \u3e .05). Conclusions The lack of statistical significance in this study is likely attributed to the relationship between a small, although contextually plausible, relative caffeine dosage and an extended exercise time. The results also suggest caffeine ingestion of 3 mg.kg-1 should not be considered capable of improving sprint performance at the start of the second half

The Northern Tornadoes Project - Uncovering Canada’s True Tornado Climatology

Canada is a vast country with most of its population located along its southern border. Large areas are sparsely populated and/or heavily forested, and severe weather reports are rare when thunderstorms occur there. Thus, it has been difficult to accurately assess the true tornado climatology and risk. It is also important to establish a reliable baseline for tornado-related climate change studies. The Northern Tornadoes Project (NTP), led by Western University, is an ambitious multidisciplinary initiative aimed at detecting and documenting every tornado that occurs across Canada. A team of meteorologists and wind engineers collects research-quality data during each damage investigation, via thorough ground surveys and high-resolution satellite, aircraft and drone imaging. Crowdsourcing through social media is also key to tracking down events. In addition, NTP conducts research to improve our ability to detect and accurately assess tornadoes that affect forests, cropland and grassland. An open data website allows sharing of resulting data sets and analyses. Pilot investigations were carried out during the warm seasons of 2017 and 2018, with the scope expanding from the detection of any tornadoes in heavily forested regions of central Canada in 2017 to the detection of all EF1+ tornadoes in Ontario plus all significant events outside of Ontario in 2018. The 2019 season was the first full campaign, systemically collecting research-quality tornado data across the entire country. To date, the Project has found 89 tornadoes that otherwise would not have been identified, and increased the national tornado count in 2019 by 78%. © 2020 American Meteorological Societ