56 research outputs found

    2012 Haida Gwaii Mw 7.7 Earthquake Response - Ocean Bottom Seismometer Relocation and Geophone Orientation Analysis and Quality Control of Wide-Angle P-wave Refraction Data

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    Canada's second largest instrumentally recorded earthquake occurred on October 27th, 2012, off the west coast of Moresby Island, Haida Gwaii. Analysis of seismic waveforms and the pattern of aftershocks indicate that it was a thrust earthquake with a magnitude of Mw = 7.7. To accurately locate earthquakes, recording stations need to be positioned such that they surround the epicenter and the sound speed at which seismic waves travel through the earth's crust must be known. The land stations on Haida Gwaii are all to the east of the aftershock sequence, thus making these offshore earthquake locations uncertain and making depths for those events almost impossible to calculate accurately. Only sparse information from seismic refraction work conducted in the early 1980ies on the offshore velocity structure around the epicenter is known. Therefore, a series of 14 ocean bottom seismometers (OBS) were deployed for the duration of 1 month between December 6, 2012 and January 5, 2013 to record a portion of the aftershock sequence. An active source seismic program was conducted in January 2013 prior to the OBS recovery to acquire information on the sediment- and crustal structures to aid in the earthquake location analyses. However, the initial refraction data were not recorded on any of the 14 OBS as the batteries on all of the OBS stations had drained by the time of the survey. An extra set of six OBS was re-deployed and a total of four single-channel seismic profiles were acquired across these six OBS stations for a smaller-scale detailed refraction velocity experiment. Using the active source seismic data, each of the six OBS of the second deployment were re-located on the ocean floor, which is a critical pre-requisite for any velocity analysis. The OBS instruments drifted on average by 200m to the NW of the deployment drop-position. New offset information for the relocated OBS stations were calculated, and used for an initial exemplary but non-ray-tracing based 1D refraction velocity analysis on selected OBS stations to demonstrate the general utility of the OBS refraction data. Additional particle motion analyses were conducted for five of the six OBS stations of the second refraction survey to define the geophone orientation. One of these six stations (OBS-5) appeared to have identical horizontal components and therefore could not be used for a geophone-orientation determination. Long-range refraction seismic arrivals from the active-source experiment with a single 520 cubic inch G-gun were identified on some of the Haida Gwaii land-stations with offset ranges of up to 58 km. This information can potentially be used for a deep-crustal refraction velocity analysis. At this stage, only basic information on these land-station data is documented for potential future analyses

    The 28 November 2020 Landslide, Tsunami, and Outburst Flood – A Hazard Cascade Associated With Rapid Deglaciation at Elliot Creek, British Columbia, Canada

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    We describe and model the evolution of a recent landslide, tsunami, outburst flood, and sediment plume in the southern Coast Mountains, British Columbia, Canada. On November 28, 2020, about 18 million m3 of rock descended 1,000 m from a steep valley wall and traveled across the toe of a glacier before entering a 0.6 km2 glacier lake and producing >100-m high run-up. Water overtopped the lake outlet and scoured a 10-km long channel before depositing debris on a 2-km2 fan below the lake outlet. Floodwater, organic debris, and fine sediment entered a fjord where it produced a 60+km long sediment plume and altered turbidity, water temperature, and water chemistry for weeks. The outburst flood destroyed forest and salmon spawning habitat. Physically based models of the landslide, tsunami, and flood provide real-time simulations of the event and can improve understanding of similar hazard cascades and the risk they pose

    Epidemiologic Relationships Between A1C and All-Cause Mortality During a Median 3.4-Year Follow-up of Glycemic Treatment in the ACCORD Trial

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    OBJECTIVERandomized treatment comparing an intensive glycemic treatment strategy with a standard strategy in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial was ended early because of an unexpected excess of mortality in the intensive arm. As part of ongoing post hoc analyses of potential mechanisms for this finding, we explored whether on-treatment A1C itself had an independent relationship with mortality.RESEARCH DESIGN AND METHODSParticipants with type 2 diabetes (n = 10,251 with mean age 62 years, median duration of diabetes 10 years, and median A1C 8.1%) were randomly assigned to treatment strategies targeting either A1C 7%.CONCLUSIONSThese analyses implicate factors associated with persisting higher A1C levels, rather than low A1C per se, as likely contributors to the increased mortality risk associated with the intensive glycemic treatment strategy in ACCORD

    The October 2012 magnitude (Mw) 7.8 earthquake offshore Haida Gwaii, Canada

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    Alison L. Bird et al. report on the Mw 7.8 earthquake offshore Haida Gwaii, Canada, from 2012 for the Summary of the Bulletin of the International Seismological Centre

    Genetic Discrimination Between LADA and Childhood-Onset Type 1 Diabetes Within the MHC

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    OBJECTIVE The MHC region harbors the strongest loci for latent autoimmune diabetes in adults (LADA); however, the strength of association is likely attenuated compared with that for childhood-onset type 1 diabetes. In this study, we recapitulate independent effects in the MHC class I region in a population with type 1 diabetes and then determine whether such conditioning in LADA yields potential genetic discriminators between the two subtypes within this region. RESEARCH DESIGN AND METHODS Chromosome 6 was imputed using SNP2HLA, with conditional analysis performed in type 1 diabetes case subjects (n = 1,985) and control subjects (n = 2,219). The same approach was applied to a LADA cohort (n = 1,428) using population-based control subjects (n = 2,850) and in a separate replication cohort (656 type 1 diabetes case, 823 LADA case, and 3,218 control subjects). RESULTS The strongest associations in the MHC class II region (rs3957146, beta [SE] = 1.44 [0.05]), as well as the independent effect of MHC class I genes, on type 1 diabetes risk, particularly HLA-B*39 (beta [SE] = 1.36 [0.17]), were confirmed. The conditional analysis in LADA versus control subjects showed significant association in the MHC class II region (rs3957146, beta [SE] = 1.14 [0.06]); however, we did not observe significant independent effects of MHC class I alleles in LADA. CONCLUSIONS In LADA, the independent effects of MHC class I observed in type 1 diabetes were not observed after conditioning on the leading MHC class II associations, suggesting that the MHC class I association may be a genetic discriminator between LADA and childhood-onset type 1 diabetes.Peer reviewe

    Protein and Overtraining: Potential Applications for Free-Living Athletes

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    Despite a more than adequate protein intake in the general population, athletes have special needs and situations that bring it to the forefront. Overtraining is one example. Hard-training athletes are different from sedentary persons from the sub-cellular to whole-organism level. Moreover, competitive, "free-living" (less-monitored) athletes often encounter negative energy balance, sub-optimal dietary variety, injuries, endocrine exacerbations and immune depression. These factors, coupled with "two-a-day" practices and in-season demands require that protein not be dismissed as automatically adequate or worse, deleterious to health. When applying research to practice settings, one should consider methodological aspects such as population specificity and control variables such as energy balance. This review will address data pertinent to the topic of athletic protein needs, particularly from a standpoint of overtraining and soft tissue recovery. Research-driven strategies for adjusting nutrition and exercise assessments will be offered for consideration. Potentially helpful nutrition interventions for preventing and treating training complications will also be presented

    The 28 November 2020 landslide, tsunami, and outburst flood – a hazard cascade associated with rapid deglaciation at Elliot Creek, British Columbia, Canada

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    We describe and model the evolution of a recent landslide, tsunami, outburst flood, and sediment plume in the southern Coast Mountains, British Columbia, Canada. On November 28, 2020, about 18 million m3 of rock descended 1,000 m from a steep valley wall and traveled across the toe of a glacier before entering a 0.6 km2 glacier lake and producing >100-m high run-up. Water overtopped the lake outlet and scoured a 10-km long channel before depositing debris on a 2-km2 fan below the lake outlet. Floodwater, organic debris, and fine sediment entered a fjord where it produced a 60+km long sediment plume and altered turbidity, water temperature, and water chemistry for weeks. The outburst flood destroyed forest and salmon spawning habitat. Physically based models of the landslide, tsunami, and flood provide real-time simulations of the event and can improve understanding of similar hazard cascades and the risk they pose

    First Genome-Wide Association Study of Latent Autoimmune Diabetes in Adults Reveals Novel Insights Linking Immune and Metabolic Diabetes

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    OBJECTIVELatent autoimmune diabetes in adults (LADA) shares clinical features with both type 1 and type 2 diabetes; however, there is ongoing debate regarding the precise definition of LADA. Understanding its genetic basis is one potential strategy to gain insight into appropriate classification of this diabetes subtype.RESEARCH DESIGN AND METHODSWe performed the first genome-wide association study of LADA in case subjects of European ancestry versus population control subjects (n = 2,634 vs. 5,947) and compared against both case subjects with type 1 diabetes (n = 2,454 vs. 968) and type 2 diabetes (n = 2,779 vs. 10,396).RESULTSThe leading genetic signals were principally shared with type 1 diabetes, although we observed positive genetic correlations genome-wide with both type 1 and type 2 diabetes. Additionally, we observed a novel independent signal at the known type 1 diabetes locus harboring PFKFB3, encoding a regulator of glycolysis and insulin signaling in type 2 diabetes and inflammation and autophagy in autoimmune disease, as well as an attenuation of key type 1-associated HLA haplotype frequencies in LADA, suggesting that these are factors that distinguish childhood-onset type 1 diabetes from adult autoimmune diabetes.CONCLUSIONSOur results support the need for further investigations of the genetic factors that distinguish forms of autoimmune diabetes as well as more precise classification strategies.Peer reviewe
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