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Hydraulic fracturing (HF) can trigger induced seismicity, but documented occurrences tend to be localized compared with the regional extent of industry operations. Factors that determine intrinsic geological susceptibility of a given region to induced seismicity remain incompletely understood. To address this uncertainty, we have developed a stochastic modeling approach to enable statistical testing of hypotheses regarding the distribution of induced seismicity. For reference, we adopted a null hypothesis that HF-induced seismic events are randomly associated with HF wells. Realizations of synthetic induced-seismicity catalogs are generated based on the Gutenberg–Richter relationship for magnitudes and explicit assumed spatial relationship(s) between HF wells and other known features, such as mapped structural corridors. Uncertainties in observed event locations and magnitudes are also considered. Based on 1000 independent realizations for each test scenario, normalized correlation coefficients, Bayesian information criteria and other statistical measures are used to quantify the similarity of synthetic catalogs to the observed seismicity distribution. We applied this approach to induced seismicity associated with HF operations within the Montney Formation, in western Canada. Three hypotheses were tested, each showing a statistically significant improvement over the null hypothesis. A previous machine-learning-based model for Seismogenic Activation Potential (SAP) showed the highest correlation between observed and synthetically generated seismicity catalogs. Our method has been developed using cloud-based computing and is easily adapted to other regions and data types. [ABSTRACT FROM AUTHOR]

Objectives: 1) To determine which characteristics of adolescent athletes with SRC are associated with 'early' versus 'late' presentation for multimodal treatment; 2) to build a propensity score to investigate the effects of treatment timing during the management of SRCs. Methods: Associations between early (0-7 days) versus late (8-28 days) presentation for treatment and pre-specified sociodemographic, pre-injury and injury characteristics were investigated in a historical cohort study of 2949 multi-sport athletes across Canada aged 12-18 years diagnosed with a SRC in community-based healthcare clinics. Results: Early presentation was associated with being male, completing a pre-injury baseline assessment, and responding 'yes' or 'no' to having a diagnosed learning disability. Older athletes who reported previous SRCs were less likely to present early. The propensity score demonstrated an area under the curve of 0.71 (95% CI, 0.69 to 0.73). Conclusions: Male athletes with a completed baseline assessment were more likely to seek early treatment following a SRC, and older athletes who reported a greater number of previous SRCs were less likely to present early. External validation of the propensity score is needed before examining the impact of treatment timing on adolescent athlete recovery outcomes. [ABSTRACT FROM AUTHOR]

Vitamin B6 is important in fetal development, but little is known of the vitamin B6 status of pregnant women and newborns in North America and potential modifying factors. This prospective study determined maternal and cord plasma concentrations of pyridoxal 5′ phosphate (PLP; an indicator of vitamin B6 status) in a convenience sample of 368 Canadian pregnant women and their newborns. The association of maternal intake of vitamin B6 and fetal genetic variants with cord plasma PLP and homocysteine concentrations was also examined. Dietary and supplemental intakes of vitamin B6 were assessed in early and mid to late pregnancy. PLP concentrations were measured in maternal plasma in early pregnancy and at delivery, and in cord plasma. Six fetal variants of the MTHFR and CβS genes were assessed for their association with cord plasma PLP and homocysteine concentrations. Geometric mean (95% CI) PLP concentrations were 107 (98, 116) nmol/L in early pregnancy and 58 (53, 62) nmol/L at delivery, respectively, and 296 (275, 319) nmol/L in cord blood ( p < .0001). During early pregnancy and at delivery, 3.6% and 5.5% of women had plasma PLP concentrations <20 nmol/L, respectively. Ninety eight percent of the women with supplemental B6 intake of at least the recommended dietary allowance had PLP concentrations >20 nmol/L. Fetal genetic variants were not associated with cord PLP and homocysteine concentrations. Vitamin B6 deficiency is uncommon in a cohort of Canadian pregnant women due largely to prevalent vitamin B6 supplement use. [ABSTRACT FROM AUTHOR]

Objectives: The objective of this study was to investigate the degree of knowledge that sports chiropractors have in regard to concussion diagnosis and management. Methods: A concussion knowledge survey was administered to Sport Chiropractic Fellows of the Royal College of Chiropractic Sports Sciences - Canada (RCCSS(C)) (n=44) via SurveyMonkey.com. Results: Sports chiropractors scored statistically higher on the survey when compared to chiropractic residents (mean =5.57 vs. 5.25; t=2.12; p=0.04) and to fourth year chiropractic interns (mean = 5.57 vs 5.2; t=2.45; p=0.02). Additionally, with our modified scoring, the sports chiropractors scored 85.3%. A few knowledge gaps were identified in the sample population. Conclusion: Sports chiropractors demonstrated the skills and knowledge to diagnose concussion and excel at identifying the definition and mechanism of concussion, but knowledge gaps regarding diagnosis and management of concussion were found in the sample population. [ABSTRACT FROM AUTHOR]

The bias correction of climate model outputs is based on the main assumption of the time invariance of the bias, in which the statistical relationship between observations and climate model outputs in the historical period stays constant in the future period. The present study aims to assess statistical bias correction under nonstationary bias conditions and its implications on the simulated streamflow over two snowmelt-driven Canadian catchments. A pseudoreality approach is employed in order to derive a proxy of future observations. In this approach, CRCM-ECHAM5 ensemble simulations are used as pseudoreality observations to correct for bias in the CRCM-CGCM3 ensemble simulations in the reference (1971-2000) period. The climate model simulations are then bias corrected in the future (2041-70) period and compared with the future pseudoreality observations. This process demonstrates that biases (precipitation and temperature) remain after the bias correction. In a second step, the uncorrected and bias-corrected CRCM-CGCM3 simulations are used to drive the Soil and Water Assessment Tool (SWAT) hydrological model in both periods. The bias correction decreases the error on mean monthly streamflow over the reference period; such findings are more mixed over the future period. The results of various hydrological indicators show that the climate change signal on streamflow obtained with uncorrected and bias-corrected simulations is similar in both its magnitude and its direction for the mean monthly streamflow only. Regarding the indicators of extreme hydrological events, more mixed results are found with site dependence. All in all, bias correction under nonstationary bias is an additional source of uncertainty that cannot be neglected in hydrological climate change impact studies. [ABSTRACT FROM AUTHOR]

The article presents the study that explores on the use of haematopoietic stem cell transplantation (SCT) in the treatment of Fanconi anemia (FA) patients in Canada and the U.S. The topics discussed include the attributes of FA, the factors that influenced the decision making of FA patients and family members on SCT, and the benefits and probable risks of SCT.

Noninferiority (NI) trials aim to show that a new treatment or drug is not inferior to a standard, accepted treatment. The rapid proliferation of NI trials within the literature makes it imperative for emergency physicians to be able to read, interpret, and appraise critically this type of research study. Using several emergency medicine examples from the recent literature, this article outlines the key differences between traditional, superiority randomized controlled trials and NI trials. We summarize four important points that an emergency physician should consider when critically appraising an NI trial: 1) Does the new treatment have tangible benefits over the standard treatment? 2) Was the choice of the NI margin appropriate? 3) Was the effect of the standard treatment preserved? Does the trial have assay sensitivity? and 4) What type of analysis strategy was employed: intention-to-treat (ITT) or per protocol (PP)? [ABSTRACT FROM PUBLISHER]

Purpose: Although quality improvement (QI) is an integral part of cancer care, there are few QI publications in the medical oncology literature. We examined the prevailing attitudes of medical oncologists toward QI and causes for the low QI publication rate in the medical oncology literature. Methods: Using a modified Dillman method, we distributed a 13-question online survey to medical oncologists across Canada asking about their attitudes toward and involvement in QI and perceived barriers to publishing QI studies. Results: We attained a 43% response rate (143 of 332). Of the responding oncologists, 97% (138) agreed that QI was an important aspect of their practice, although only 49% (70) had participated in QI in the past 5 years. Physicians with administrative responsibility were more likely than clinicians to be involved in QI (P = .008). Most QI participants focused on domains of safety (70%) and patient centeredness (67%). Among QI participants, 72% did not publish their findings, because of lack of time (34%), no identifiable journals (14%), and unfamiliarity with QI methodology (10%). Barriers for QI nonparticipants included uncertainty about how to get involved (45%), lack of time (18%), and limited institutional support or recognition (18%). QI participants had greater awareness of recent practice-changing QI publications compared with nonparticipants (P = .003). Conclusion: Canadian medical oncologists face limitations to participating in and publishing QI initiatives because of lack of knowledge about ongoing initiatives, lack of time, and lack of resources to aid publication. Improving networking opportunities and prioritizing QI at the institutional level can address this need. [ABSTRACT FROM AUTHOR]

Context: The known detrimental effects of sport concussions on motor system function include balance problems, slowed motor execution, and abnormal motor cortex excitability. Objective: To assess whether these concussion-related alterations of motor system function are still evident in collegiate football players who sustained concussions but returned to competition more than 9 months before testing. Design: Case-control study. Setting: University laboratory. Patients or Other Participants: A group of 21 active, university-level football players who had experienced concussions was compared with 15 university football players who had not sustained concussions. Intervention(s): A force platform was used to assess center-of-pressure (COP) displacement and COP oscillation regularity (approximate entropy) as measures of postural stability in the upright position. A rapid alternating-movement task was also used to assess motor execution speed. Transcranial magnetic stimulation over the motor cortex was used to measure long- interval intracortical inhibition and the cortical silent period, presumably reflecting γ-aminobutyric acid subtype B receptor- mediated intracortical inhibition. Main Outcome Measure(s): COP displacement and oscillation regularity, motor execution speed, long-interval intracortical inhibition, cortical silent period. Results: Relative to controls, previously concussed athletes showed persistently lower COP oscillation randomness, normal performance on a rapid alternating-movement task, and more M1 intracortical inhibition that was related to the number of previous concussions. Conclusions: Sport concussions were associated with pervasive changes in postural control and more M1 intracortical inhibition, providing neurophysiologic and behavioral evidence of lasting, subclinical changes in motor system integrity in concussed athletes. [ABSTRACT FROM AUTHOR]

Estimating number of prey killed by carnivores such as wolves (Canis lupus) per unit time, or kill rate, is important for the conservation and management of carnivores and their prey. We reviewed published methods to estimate wolf kill rates and found them inconsistent and lacking a basis in statistical sampling theory. We developed a general statistical estimator for kill rate and variance using ratio-variable sampling theory. We illustrate our ratio estimator by estimating wolf kill rates in a multiple-prey system in Banff National Park, Alberta, for winters from 1986 to 2000. We used snow tracking and radiotelemetry to locate 429 kills during 195 sampling intervals covering 1,294 days. Mean kill rate by wolf packs (expressed as the number of kills/day/pack, k/d/p) was 0.33 k/d/p, most of which, 0.23 k/d/p, were elk (Cervus elaphus), the most abundant ungulate. Kill-rate estimates were variable despite intensive sampling effort. The mean kill rate of 0.33 k/d/p had a pooled 95% confidence interval of 0.29 to 0.37. An intensive sampling effort of ≥6-8 individual sampling intervals covering approximately 25% of the winter was required to minimize sampling variation. We compared our method to 3 other published methods for estimating kill rates and examined the bias and precision of kill-rate methods using simulations. Our ratio estimator approach was the least biased and most precise when compared to other approaches. Ratio estimators provide a standardized method to estimate kill rates in other predator-prey systems and will facilitate comparison across studies and examination of patterns of kill-rate variation. [ABSTRACT FROM AUTHOR]

(1) Species establishment after 3 years on artificially revegetated ski-slopes of Whistler Mountain, British Columbia, Canada and the nature of species associations were investigated in relation to altitude, slope angle and soil properties. (2) The overall establishment of seeded species from the grass-legume mixture had been satisfactory. (3) Three of the seeded species Fessuca rubra L. Phleum pratense L. and Trifolium hybridum L. had cover values greater than their relative abundance in the seed mixture, whereas the remaining seeded species, A grostis alba L. A. tenuis (Sibth.), Poa compressa L. and Trifolium repens L. were under-represented in the sward. (4) Analysis of variance was used to detect significant variations in the relative abundance of the four most abundant species in relation to altitude and slope angle. In productive habitats F. rubra and T. hybridum attained large cover values and constrained the establishment of the slower growing species, A. tenuis and P. pratense. The latter species were more abundant in resource-poor sites where competition from the productive species was reduced. (5) The vigorous, rhizomatous growth of F. rubra contributed to its dominance in the sward; its positive associations with P. pratense, detected by contact sampling and association analysis, were likely a result of differential rooting strategies. (6) The tussock habit of both A. tenuis and P. pratense restricted their co-habitation in productive sites where competition from F. rubra and T. hybridum is suggested to be most intense. [ABSTRACT FROM AUTHOR]

This article tests the hypothesis of a variable lag of shipments of capital goods behind new orders, applied to three major Canadian industries producing mainly to order. This hypothesis, confirmed by earlier studies on American data, is corroborated on the Canadian data. Several supplementary conclusions are also drawn, including a suggestion that constraining the weights in the Almon lag distribution to zero at the beginning and end of the distribution may introduce distortion into the resulting estimates. [ABSTRACT FROM AUTHOR]

Significance testing is arguably one of the most important concepts of time series analysis.Still, in many applications that include a windowed approach or a repeated analysis over acontinuous range of parameters, results are often tested for every point separately. This givesrise to the requirement of multiple testing corrections and neglects possible intrinsiccorrelations within the analysis results that may make false positive significant points ratherappear as continuous patches than as isolated points. To detect such false positive patches, wehere introduce a general concept for an areawise significance test similar to the one presentedby Maraun et al. [1] for the wavelet spectrum. There, the wavelet reproducing kernel isused to assess the scale of decay of intrinsic correlations which then determinesthe areawise test. Our test is more general and can in principle be applied to anyanalysis method but requires a numerical estimation of the scale of decay of theintrinsic correlations. This estimation can be achieved by choosing a null modeland then calculating correlation functions of the analysis results of surrogate datafollowing the null model for overlapping time windows or for the varying analysisparameters. We here apply the areawise test to windowed and multiscale windowed recurrencenetwork analysis in order to identify dynamical anomalies in palaeoclimate archives such as,for example, tree rings. In this context, recurrence based methods have already proven to bevaluable tools but significance tests have so far only be restricted to pointwise tests. To applythe areawise test, we consider three null models, (i) Gaussian white noise, (ii) anAR(1) process and (iii) a data-adaptive model using iAAFT surrogates. For each nullmodel, we create corresponding sets of surrogate data and then estimate the scale ofdecay of the intrinsic correlations of the measure of interest in the time and windowwidth domains for windowed recurrence network analysis, and in the time andscale domains for multiscale windowed recurrence network analysis. To test ourapproach, we first study a non-stationary Rössler system and then apply the proposedanalysis procedure to a paleoclimate time series of tree ring width indices fromEast Canada. We find dynamical anomalies in times following major explosivevolcanic eruptions depending on the chosen embedding delay, possibly reflecting thatdifferent volcanic eruptions cause dynamical responses on different time scales. Still,to draw reliable conclusions about this effect, more proxy time series need to beanalysed. [1] D. Maraun, J. Kurths, and M. Holschneider. Nonstationary gaussian processes inwavelet domain: Synthesis, estimation, and significance testing. Phys. Rev. E, 75:016707,2007. [ABSTRACT FROM AUTHOR]