382 research outputs found

    Tornadoes in Canada: Improving our Understanding

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    Environment Canada presentation at ICLR What is a tornado? How do tornadoes form? How are tornadoes rated? Where / when do tornadoes occur? How does EC provide tornado alerts? Are tornadoes in Canada increasing in frequency and/or intensity

    Northern Tornadoes Project. Annual Report 2021 v2

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    The Northern Tornado Project’s third year of detecting, assessing and documenting tornadoes and other damaging wind events across Canada saw some interesting extremes – tornadoes in parts of both the Atlantic and Pacific coasts for the first time in decades, an apparent absence of tornadoes on the Prairies over the 60 days with the highest climatological frequency, a record number of significant (EF2+) tornadoes in Ontario, and massive downbursts in NE British Columbia, NW Alberta and SW Northwest Territories associated with an historic ‘heat dome’. On top of this, the COVID-19 pandemic was still spreading across the country in waves. Thankfully, it subsided enough over the summer that NTP teams were able to travel safely to various locations across the country for ground surveys. Some of the most challenging ground surveys investigated high-impact damage from the July 15th EF2 Barrie, Ontario tornado, and others significant tornadoes from that day. Since 2019, founding partners Western University and ImpactWX, in conjunction with other partners and collaborators, have been undertaking the most comprehensive tornado analyses ever made in Canada. In 2021, we were able to bring on new partners (Instant Weather, CatIQ) and new staff members (bilingual research assistant Francis Lavigne-Theriault, Western Libraries GIS Technical Specialist Jordan Fuller). We also sadly lost one of our external research partners, Arn Womble. In addition, the public-facing Dashboard and Open Data Site have become more useful and user friendly. Together with our research, it is a step towards fulfilling our vision that Canadians are better informed about tornadoes and are able to better protect their homes and communities. We’ve also continued to be community driven. We initiated a Super-Contributor program to recognize our most active and knowledgeable contributors of social media reports and data (and rewarded them with stylish NTP ball caps!). We’ve made numerous media appearances, some national in scope, as well as given NTP talks to a number of different organizations. You’ll find the details in the pages of our annual report

    Assessment of Tornado Alerting Performance for Canada

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    The Northern Tornadoes Project (NTP) completed a first independent assessment of national tornado warning alerting (watches and warnings) in Canada covering the 2019–2021 period. The NTP undertook this study in the spirit of open data, understanding tornado warning issues unique to this country, and improving tornado warning performance. Utilizing the NTP tornado event database for verification, tornado alerts were reviewed for accuracy and timeliness. For the 250 tornadoes that occurred during the study period–and using a definition of what constitutes a warning ‘hit’ developed for the study–the standard 2 × 2 contingency table scores were Probability of Detection = 0.23, FAR = 0.78, and CSI = 0.13. Over 70% of tornadoes had no tornado warning, including 35 EF2 tornadoes. The tornado warning results were compared with US National Weather Service tornado warning scores for the US and US states along the southern Canadian border to provide context. NTP also developed a ‘report card’ aimed at public and media consumption that took into consideration Environment and Climate Change Canada’s national performance targets for tornado warning Probability of Detection (POD) and lead time as well as tornado watch issuance. Using weighted scores for these criteria, NTP assigned a total score of 33.3/100, indicating significant room for improvement. A follow-up assessment was conducted for the 2022 tornado season in Canada following the same established procedures. It was found that the number of both tornado watches and tornado warnings had roughly doubled, resulting in a significant increase in the POD for tornado warnings to 0.35. The report card score also improved to a passing grade of 56.6/100. Further exploration of the results showed enhanced performance for tornadoes that occurred within Doppler radar range, when the parent thunderstorm involved supercell processes, and for tornadoes rated EF2 or higher. A number of recommendations are made aimed at further improvements to tornado alerting performance

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

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    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

    Northern Tornadoes Project. Northern Tornadoes Flyover Project: Summary Technical Report of the Year 1 Pilot Study

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    Summary Northern Tornadoes Flyover Project: Summary Technical Report of the Year 1 Pilot Study Gregory A. Kopp, Emilio Hong and Joanne Kennell Faculty of Engineering, University of Western Ontario David Sills Environment and Climate Change Canada 12 January 2018 The objectives of the Year 1 Pilot Study were to (i) develop a methodology for determining tornado occurrence in Northern Ontario, and (ii) obtain research quality data for at least one event. Because of the isolation of many regions, the approach assumed the use of radar data analysis combined with aerial surveys. These objectives were achieved. Aerial surveys were conducted for a total of seven events in Ontario and southern Quebec and 15 confirmed or probable tornadoes identified. Archival geo-tagged imagery was obtained for six of these events. Ten confirmed or probable tornadoes were identified in Ontario, five of which were not in the OSPC database. In addition, 5 tornadoes were confirmed in Quebec. For the 2017 season, the OSPC had a list of 10 verified tornadoes, as of December 21, 2017. The pilot project raises this number to 15. In total, 4 EF2 tornadoes and 1 EF3 tornado were identified via aerial photography. The remainder were EF1 or EF0. UPDATE – 1 March 2021 Based on the analysis of newly available Planet.com high-resolution satellite imagery and the use of related tools, events were reassessed and six additional tornadoes were discovered. However, four tornadoes were reassessed as downbursts. Overall, an additional two tornadoes were added to the 2017 count. The updated events are listed in a revised 2017 summary table appended at the end of this document

    The Fabric of Clasts, Veins and Foliations within the Actively Creeping Zones of the San Andreas Fault at SAFOD: Implications for Deformation Processes

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    Recovered core samples from the San Andreas Fault Observatory at Depth (SAFOD), located near Parkfield, CA, offer a unique opportunity to study the products of faulting and to learn about the mechanisms of slip at 3 km depth. Casing deformation reflects active creep along two strands of the San Andreas Fault (SAF) at SAFOD. The two fault strands are referred to as the Southwest Deforming Zone (SDZ) at 3194 m measured depth (MD) and the Central Deforming Zone (CDZ) at 3301 m MD. The SDZ and CDZ contain remarkably similar gouge layers, both of which consist of a clay-bearing, ultrafine grain matrix containing survivor clasts of sandstone and serpentinite. The two gouges have sharp boundary contacts with the adjacent rocks. We have used X-ray Computed Tomography (XCT) imaging, at two different sampling resolutions, to investigate the mesoscale and microscale structure of the fault zone, specifically to characterize the shape, preferred orientation, and size distribution of the survivor clasts. Using various image processing techniques, survivor clast shape and size are characterized in 3D by best-fit ellipsoids. Renderings of survivor clasts illustrate that survivor clasts have fine tips reminiscent of sigma type tails of porphyroclasts observed in myolonites. The resolution of the XCT imaging permits characterization of survivor clasts with equivalent spherical diameters greater than 0.63 mm. The survivor clast population in both the SDZ and CDZ gouge layers have similar particle size distributions (PSD) which fit a power law with a slope of approximately -3; aspect ratio (major to minor axis ratios) distributions also are similar throughout ranging between 1.5 and 4, with the majority occurring between 2-2.5. The volume- and shape- distributions vary little with position across the gouge zones. A strong shape preferred orientation (SPO) exists in both creeping zones. In both the SDZ and CDZ the minor axes form a SPO approximately normal to the plane of the San Andreas Fault (SAF), and the major axes define a lineation in the plane of the SAF. The observation that the size-, shape- and orientation-distributions of mesoscale, matrix-supported clasts are similar in the SDZ and CDZ gouge layers, and vary little with position in each gouge layer, is consistent with the hypothesis that aseismic creep in the SDZ and CDZ is achieved by distributed, shearing. The consistency between the SPO and simple-shear, strike-slip kinematics, and the marked difference of PSD, fabric, cohesion and clast lithology of the gouge with that of the adjacent rock, is consistent with the hypothesis that the vast majority of the shear displacement on the SAF at SAFOD is accommodated within the gouge layers and the gouge displays a mature, nearly steady-state structure

    A need for definition: a matter of life and death for human embryos

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    A recent IMJ commentaryon brain stem death criteria summarised ethical and technical issues concerning “end of life decisions”, and we concur that physicians should have competence in eliciting the proper sequence of brain stem signs in clinical practice. However, a truly comprehensive dialogue on the definition of death should address another question that confronts IVF clinics in Ireland each day—when does a human embryo die? Despite the enormous social and political energy focused on “right to life” issues over recent decades, the death of a human embryo remains a sadly forgotten topic. As Dr Murphy indicated1, the introduction of brain stem death criteria in 1967 recognised permanent loss of consciousness and spontaneous breathing after the inactivation of essential human neural elements. But our IVF clinics and allied research facilities are responsible for human life well before any discrete neurological system has developed. For practitioners and scientists engaged in the care of these tiniest of “patients”, a relevant definition of death should not be neglected

    Epilepsy and the inflammasome: targeting inflammation as a novel therapeutic strategy for seizure disorders

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    Epilepsy is the most common serious brain disorder worldwide. Recent evidence from experimental models of epilepsy and clinical brain tissue from epilepsy surgery suggests inflammation may play a pathological role in this disorder. Activation of a multimolecular protein complex termed the ‘inflammasome’ occurs during inflammation to drive the innate immune response. Inflammasome activation, with release of inflammatory mediators including interleukin-1β and high-mobility group box-1, may play a crucial role in the development of epilepsy (epileptogenesis) after brain insult. Immunomodulatory drugs targeting the inflammasome pathway may represent a novel antiepileptogenic treatment strategy for epilepsy. This review summarises the current literature surrounding inflammasome activation and epilepsy

    Recipient screening in IVF: First data from women undergoing anonymous oocyte donation in Dublin

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    BACKGROUND: Guidelines for safe gamete donation have emphasised donor screening, although none exist specifically for testing oocyte recipients. Pre-treatment assessment of anonymous donor oocyte IVF treatment in Ireland must comply with the European Union Tissues and Cells Directive (Directive 2004/23/EC). To determine the effectiveness of this Directive when applied to anonymous oocyte recipients in IVF, we reviewed data derived from selected screening tests performed in this clinical setting. METHODS: Data from tests conducted at baseline for all women enrolling as recipients (n = 225) in the anonymous oocyte donor IVF programme at an urban IVF referral centre during a 24-month period were analysed. Patient age at programme entry and clinical pregnancy rate were also tabulated. All recipients had at least one prior negative test for HIV, Hepatitis B/C, chlamydia, gonorrhoea and syphilis performed by her GP or other primary care provider before reproductive endocrinology consultation. RESULTS: Mean (±SD) age for donor egg IVF recipients was 40.7 ± 4.2 yrs. No baseline positive chlamydia, gonorrhoea or syphilis screening results were identified among recipients for anonymous oocyte donation IVF during the assessment interval. Mean pregnancy rate (per embryo transfer) in this group was 50.5%. CONCLUSION: When tests for HIV, Hepatitis B/C, chlamydia, gonorrhoea and syphilis already have been confirmed to be negative before starting the anonymous donor oocyte IVF sequence, additional (repeat) testing on the recipient contributes no new clinical information that would influence treatment in this setting. Patient safety does not appear to be enhanced by application of Directive 2004/23/EC to recipients of anonymous donor oocyte IVF treatment. Given the absence of evidence to quantify risk, this practice is difficult to justify when applied to this low-risk population
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