The Hunt for Missing Tornadoes: Using Satellite Imagery to Detect and Document Historical Tornado Damage in Canadian Forests

Historical tornado events from 1982 to 2020 were documented within Canada’s forested regions using high-resolution satellite imagery. Tornado forest disturbances were identified using a three-step process: 1) detecting, 2) assessing, and 3) dating each event. A grid of 120 km 3 120 km boxes was created covering Canada (excluding the extreme north). Of the 484 boxes, 367 were manually searched. Once a long, narrow region of tree damage was detected, it was first cross-referenced with known tornado databases to ensure it was a unique event. Once events were classified as either tornadic or downburst, the coordinates of the start, worst damage, and end locations were documented, as well as the direction of motion, damage indicators, degree of damage, estimated maximum wind speed, and F/EF-scale rating. In total, 231 previously unknown tornadoes were identified. In Ontario, 103 events were discovered, followed by 98 in Quebec, 9 in Manitoba, 6 in Saskatchewan, 9 in Alberta, 5 in British Columbia, and 1 in New Brunswick. The largest number of discovered tornadoes occurred in 2015, and the largest number of strong F2 tornadoes occurred in 2005. Most of the discovered tornadoes occurred in July for both F/EF1 and F/EF2 ratings. Most tornado tracks had widths between 200 and 400 m, and more than 50% of the tornadoes had a pathlength of less than 10 km. Of all the events that were discov-ered, 125 events could be fully dated, 19 were dated only by month, 41 were dated only by year, and 46 remained undated

Perfidious Albion revisited: Anglo-Australian trade relations and European economic integration

...This paper explores the history of Anglo-Australian trade relations over the course of Britain’s uncertain and at times faltering path towards economic integration with Europe. Anxiety about being kept in the dark over British economic links with Europe dates back at least to the Chifley government. Despite new sources of tension in Anglo-Australian trade relations in the 1950s, Australia placed considerable faith in repeated British assurances that nothing would be done to diminish Commonwealth economic links. As such, John Crawford (1968: 268) would claim that Britain’s application to join the EEC in mid 1961 was a reversal of ‘all previous declarations of policy’ and that it came as ‘a major shock to the Australian public, even if ministers and officials had been less unaware of a possible change’. This reversal was seen as nothing less than an affront to Australian (and British) conceptions of fair play...

Boundary data smoothness for solutions of nonlocal boundary value problems for second order differential equations

AbstractUnder certain conditions, solutions of the boundary value problem, y″=f(x,y,y′), y(x1)=y1, and y(x2)−∑i=1mriy(ηi)=y2, are differentiated with respect to boundary conditions, where a<x1<η1<⋯<ηm<x2<b, r1,…,rm∈R, and y1,y2∈R

From Eden to Sahara : Florida\u27s tragedy

Kitchen-middens of the Upper Eastern Coast pg. 13 Kitchen-middens of the Upper Western Coast pg. 30 Some Hammocks of the Everglade Keys pg. 46 A Prehistoric Canal at Cape Sable pg. 54 Aboriginal Activities at Cape Romano pg. 56 A Detour across the Peninsula pg. 78 A Cruise amonf the Florida Keys pg. 85 Aboriginal Ruins on Bay Biscayne pg. 94 Mounds of Floristics of Cape Sable pg. 99 Observations along the East Coast pg. 106 Prophecies pg. 11

A framework for examining climate-driven changes to the seasonality and geographical range of coastal pathogens and harmful algae

AbstractClimate change is expected to alter coastal ecosystems in ways which may have predictable consequences for the seasonality and geographical distribution of human pathogens and harmful algae. Here we demonstrate relatively simple approaches for evaluating the risk of occurrence of pathogenic bacteria in the genus Vibrio and outbreaks of toxin-producing harmful algae in the genus Alexandrium, with estimates of uncertainty, in U.S. coastal waters under future climate change scenarios through the end of the 21st century. One approach forces empirical models of growth, abundance and the probability of occurrence of the pathogens and algae at specific locations in the Chesapeake Bay and Puget Sound with ensembles of statistically downscaled climate model projections to produce first order assessments of changes in seasonality. In all of the case studies examined, the seasonal window of occurrence for Vibrio and Alexandrium broadened, indicating longer annual periods of time when there is increased risk for outbreaks. A second approach uses climate model projections coupled with GIS to identify the potential for geographic range shifts for Vibrio spp. in the coastal waters of Alaska. These two approaches could be applied to other coastal pathogens that have climate sensitive drivers to investigate potential changes to the risk of outbreaks in both time (seasonality) and space (geographical distribution) under future climate change scenarios

Dephasing mechanisms of optical transitions in rare-earth-doped transparent ceramics

We identify and analyze dephasing mechanisms that broaden the optical transitions of rare-earth ions in randomly oriented transparent ceramics. The study examines the narrow F_0^7 ↔ D_0^5 transition of Eu^(3+) dopants in a series of Y_2O_3 ceramic samples prepared under varying conditions. We characterize the temperature and magnetic field dependence of the homogeneous linewidth, as well as long-term spectral diffusion on time scales up to 1 s. The results highlight significant differences between samples with differing thermal treatments and Zr^(4+) additive concentrations. In particular, several distinct magnetic interactions from defect centers are observed, which are clearly distinguished from the broadening due to interactions with two-level systems and phonons. By minimizing the broadening due to the different defect centers, linewidths of the order of 4 kHz are achieved for all samples. The linewidths are limited by temperature-dependent interactions and by an interaction that is yet to be identified. Although the homogeneous linewidth can be narrowed further in these ceramic samples, the broadening is now comparable to the linewidths achieved in rare-earth-ion–doped single crystals. Thus, this work emphasizes the usefulness of studying ceramics to gain insights into dephasing mechanisms relevant to single crystals and suggests that ceramics may be an interesting alternative for applications in classical and quantum information processing

Analysis of resistance gene-mediated defense responses in Arabidopsis thaliana plants carrying a mutation in CPR5

In resistant plants, pathogen attack often leads to rapid activation of defense responses that limit multiplication and spread of the pathogen. To investigate the signaling mechanisms underlying this process, we carried out a screen for mutants in the signaling pathway governing resistance in Arabidopsis thaliana to the bacterial pathogen Pseudomonas syringae. This involved screening for suppressor mutations that restored resistance to a susceptible line carrying a mutation in the RPS2 resistance gene. A mutant that conferred resistance by activating defense responses in the absence of pathogens was isolated. This mutant, which carries a mutation at the CPR5 locus and was thus designated cpr5-2, exhibited resistance to P. syringae, spontaneous development of necrotic lesions, elevated PR gene expression in the absence of pathogens, and abnormal trichomes. Resistance gene-mediated defenses, including the hypersensitive response, restriction of pathogen growth, and induction of defense-related gene expression, were functional in cpr5-2 mutant plants. Additionally, in cpr5-2 plants RPS2-mediated induction of PR-1 expression was enhanced, whereas RPM1-mediated induction of ELI3 was not. These findings suggest that CPR5 encodes a negative regulator of the RPS2 signal transduction pathway