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Strachan S.A.,Environment Canada | Reynoldson T.B.,University of Canberra | Reynoldson T.B.,NS Solar Material Co.
Freshwater Science | Year: 2014

The objective of this study was to evaluate the performance of 3 bioassessment models for reference data sets collected from the Australia Capital Territory (ACT), the Yukon River Basin (YT), and the Laurentian Great Lakes (GL) built following the standard Canadian Aquatic Biomonitoring Network (CABIN) method. To evaluate the models, we used validation reference-site data, which were artificially impaired to simulate 3 levels of eutrophication by varying the proportions of sensitive, intermediate, and tolerant taxa. Models correctly classified 56 to 62% of reference sites. Type 1 errors (assessing reference sites as degraded) were high for all data sets and ranged from 30 to 75%, in part because the biological communities of the validation sites extended to or beyond the range of the reference-site data used to build the models. Capturing the full range of ecological variation with adequate sample size is critical for reference-condition approach (RCA)-type models. Type 2 errors (assessing degraded sites as in reference condition) varied greatly among data sets and for each reference group within each data set. Resource managers must carefully consider the risks associated with making errors. Thus, standard methods for quality assurance of assessment models should include simulated data so that error rates and adjusted assessment thresholds can be reported to ensure that degradation can be detected and that undisturbed sites are not mistakenly subjected to unnecessary management action. © 2014 by The Society for Freshwater Science.


Reynoldson T.B.,University of Canberra | Reynoldson T.B.,NS Solar Material Co. | Strachan S.,Environment Canada | Bailey J.L.,Laurentian University
Freshwater Science | Year: 2014

Reference Condition Approach (RCA) predictive models are used to assess a test site against reference sites probabilistically matched based on habitat. These models are the basis of several major national stream bioassessment programs in the UK, Australia, and Canada. In the usual approach to developing predictive models, discriminant function analysis (DFA) is used to assign a test site to a group of matched reference sites. These groups typically are established by classification of a macroinvertebrate assemblage and matched to the habitat attributes in a single-step DFA model. We examined an alternative to standard DFA in which a series of tiered models are used. This tiered method constructs a model for the 1st division in a hierarchical classification, and then develops models for each further step in the hierarchical classification. We examined the method with 3 training and validation data sets. Validation data consisted of data from reference sites and those same sites after they underwent simulated impairment. We compared the tiered approach to the standard approach based on prediction accuracy and Type 1 and Type 2 error rates for each data set. The tiered DFA models were similar to or slightly better than the standard single-step DFA models in correctly matching validation sites to reference groups, but this improvement in accuracy did not necessarily translate into improved bioassessment error rates. © 2014 by The Society for Freshwater Science.


Kirmayer L.J.,McGill University | Kirmayer L.J.,Jewish General Hospital | Dandeneau S.,University of Quebec at Montréal | Marshall E.,NS Solar Material Co. | And 3 more authors.
Canadian Journal of Psychiatry | Year: 2011

The notions of resilience that have emerged in developmental psychology and psychiatry in recent years require systematic rethinking to address the distinctive cultures, geographic and social settings, and histories of adversity of indigenous peoples. In Canada, the overriding social realities of indigenous peoples include their historical rootedness to a specific place (with traditional lands, communities, and transactions with the environment) and the profound displacements caused by colonization and subsequent loss of autonomy, political oppression, and bureaucratic control. We report observations from an ongoing collaborative project on resilience in Inuit, Métis, Mi'kmaq, and Mohawk communities that suggests the value of incorporating indigenous constructs in resilience research. These constructs are expressed through specific stories and metaphors grounded in local culture and language; however, they can be framed more generally in terms of processes that include: regulating emotion and supporting adaptation through relational, ecocentric, and cosmocentric concepts of self and personhood; revisioning collective history in ways that valorize collective identity; revitalizing language and culture as resources for narrative self-fashioning, social positioning, and healing; and renewing individual and collective agency through political activism, empowerment, and reconciliation. Each of these sources of resilience can be understood in dynamic terms as emerging from interactions between individuals, their communities, and the larger regional, national, and global systems that locate and sustain indigenous agency and identity. This social-ecological view of resilience has important implications for mental health promotion, policy, and clinical practice.


Heard G.J.,NS Solar Material Co.
Proceedings of Meetings on Acoustics | Year: 2013

During August 2012, acoustic recording systems were deployed in Barrow Strait as part of the Defence Research and Development Canada (DRDC) Northern Watch Technology Demonstration Project. Two Starfish Sensor Cubes each with a 1-m cube of seven hydrophones operating in the frequency range of 5 - 750 Hz, and two single-hydrophone, Autonomous Multichannel Acoustic Recorders (AMAR) providing a 30-kHz signal bandwidth were deployed. The Starfish were deployed for two one-week intervals. One AMAR was deployed for two weeks partially overlapping the Starfish deployment. The second AMAR was deployed for a period of one year with recovery planned for August 2013. The observed underwater noise picture is one of high variability ranging from an extremely quiet to a noisy environment. Noise sources included: A 500-m long iceberg grounded within 500 m of one of the Starfish; a large ice island (4-5 km2) that passed within 4 km of the sensors; a small number of motoring vessels; significant wind events that caused rapid and strong variations in the noise field; and a small number of marine mammal detections. After our departure, a large number of Beluga whales were observed visually. The remaining AMAR may detect these late summer visitors. © 2013 Acoustical Society of America.


Pecknold S.P.,NS Solar Material Co.
Proceedings of Meetings on Acoustics | Year: 2013

During the summer of 2012, a field trial was held in Barrow Strait, south of Devon Island in the Canadian Arctic. The trial included a set of acoustic transmission loss experiments recorded on Starfish Sensor Cubes, which include a 1-m cube of seven hydrophones operating in the frequency range of 5 - 750 Hz. The transmission loss runs consisted of 10-minute and 20-minute duration transmissions of 400 Hz and 500 Hz tones made at a discrete set of distances up to 60 km from the recorders. Supporting environmental measurements included sets of CTD (conductivity-temperature-depth) profiles and bathymetric measurements. The effects of the measured environmental properties and variability are investigated via propagation modeling, and compared to the experimental data acquired during these experiments. © 2013 Acoustical Society of America.


Martin B.,NS Solar Material Co.
Proceedings of Meetings on Acoustics | Year: 2013

The goal of many underwater acoustic environmental assessments is to characterize the soundscape in an area before, during or after an anthropogenic activity. The assessment determines the range of baseline noise levels from natural and anthropogenic sources and the contribution of the new anthropogenic activity. The noise levels are considered in aggregate for possible effects on the environment. It is accepted that the effects of anthropogenic noise on marine life depend on the intensity and duration of exposure, the frequency content of the sound relative to the hearing abilities of the species, and the behaviour context of the species exposed to the sounds. A growing body of scientific evidence is being analyzed to establish threshold sound levels and dose-response curves for injury or behavioural disturbance effects to marine life. Recent research is also raising new questions about the most appropriate ways to compute ambient sound levels and exposure metrics. In this paper we present our methods for quantifying ambient sound levels and anthropogenic sound levels from shipping and seismic survey activities in large data sets. We also make recommendations on how to estimate background sound levels in the presence of these sound sources. © 2013 Acoustical Society of America.


Matthews M.-N.R.,NS Solar Material Co.
Proceedings of Meetings on Acoustics | Year: 2013

In this paper, we compare airgun sound levels measured during an offshore seismic survey to acoustic model predictions. The survey occurred in deep water (>650 m), on and beyond the continental slope in the Canadian Beaufort Sea. The modeling was performed with JASCO Applied Sciences' Marine Operations Noise Model, which uses a parabolic-equation-based algorithm to predict N×2 D sound propagation in ocean environments. Sound levels were measured with up to five calibrated Autonomous Multichannel Acoustic Recorders at distances of 50 to 50,000 m from the airgun array in water depths between 50 and 1,500 m. The sound levels were measured in both the broadside (across-track) and endfire (along-track) directions. The high-resolution digital recordings of seismic sounds were analyzed to determine peak and root-mean-square sound pressure levels and sound exposure levels as functions of range from the airgun array, and compared to the model results. Although the modeled sound levels were generally conservative, the model results accurately predicted the existence of a shadow zone and the overall transmission loss trend. © 2013 Acoustical Society of America.


Ellis D.D.,NS Solar Material Co.
Proceedings of Meetings on Acoustics | Year: 2013

Reverberation measurements were made in the Gulf of Mexico off Panama City, Florida, USA in April 2012 in preparation for the main Target and Reverberation Experiment (TREX) in May 2013. The data were gathered using the triplet section of the ONR Five Octave Research Array (FORA), deployed as a fixed receiver. By steering cardioid beams to the right or left the array can reduce ambiguity. Beamformed data from the 2012 trial show background noise with high directionality and variability due to nearby shipping. Model predictions of reverberation and target are compared with data using a range-dependent Clutter Model, which uses adiabatic normal modes as the computational engine. The initial predictions use isovelocity water, over a sandy bottom halfspace with Lambert scattering, and bathymetry from the GEBCO 08 database. These initial results will be presented, hopefully supplemented by improved predictions with better environmental inputs and additional clutter data obtained during the May 2013 experiment. © 2013 Acoustical Society of America.


Martin B.,NS Solar Material Co.
Proceedings of Meetings on Acoustics | Year: 2013

The Gully Marine Protected Area (MPA) is a large submarine canyon at the edge of the Scotian Shelf, south of Nova Scotia. A resident population of northern bottlenose whales are known to occur in the Gully throughout the year, and the canyon provides important foraging grounds for the population. Bottom-mounted Autonomous Multichannel Acoustic Recorders (AMAR) were deployed in the Gully for ten days in in March 2010 (sampling rate = 375 ksps) and two days in October 2011 (sampling rate = 128 ksps). Bisonar pulses produced northern bottlenose whales (likely used to echolocate prey) were recorded consistently throughout these AMAR deployments. The swept FM characteristics of the northern bottlenose whale pulses recorded were consistent over both years, and both data sets contained clear pulse reflections from bottom clutter or prey targets. In this paper we provide a description of the northern bottlenose whale pulses recorded in the Gully and make recommendations on short-time Fourier transform parameters for analysis of the pulses. A description of the pulse reflections is also provided, based on analysis of the reflection patterns using short-time Fourier transforms and by matched filtering with the direct arrival from the whales. © 2013 Acoustical Society of America.


Majaess D.,Saint Mary's University, Halifax | Majaess D.,NS Solar Material Co. | Turner D.,Saint Mary's University, Halifax | Turner D.,NS Solar Material Co. | Gieren W.,University of Concepción
Astrophysical Journal Letters | Year: 2011

Evidence is presented which supports findings that the classical Cepheid VIC period Wesenheit function is relatively insensitive to metallicity. The viability of a recently advocated strong metallicity dependence was evaluated by applying the proposed correction (γ = -0.8magdex -1) to distances established for the Magellanic Clouds via a Galactic VIC Wesenheit calibration, which is anchored to 10 nearby classical Cepheids with measured Hubble Space Telescope (HST) parallaxes. The resulting γ-corrected distances for the Magellanic Clouds (e.g., Small Magellanic Cloud, μ0, γ ∼ 18.3) are in significant disagreement with that established from a mean of >300 published estimates (NED-D), and a universal Wesenheit template featuring 11 δ Scuti, SX Phe, RRLyrae, and Type II Cepheid variables with HST/Hipparcos parallaxes. Conversely, adopting a null correction (i.e., γ = 0magdex-1) consolidates the estimates. In tandem with existing evidence, the results imply that variations in chemical composition among Cepheids are a comparatively negligible source of uncertainty for -based extragalactic distances and determinations of H 0. A new approach is described which aims to provide additional Galactic Cepheid calibrators to facilitate subsequent assessments of the VI C Wesenheit function's relative (in) sensitivity to abundance changes. VVV/UKIDSS/Two Micron All Sky Survey JHKs photometry for clusters in spiral arms shall be employed to establish a precise galactic longitude-distance relation, which can be applied in certain cases to determine the absolute Wesenheit magnitudes for younger Cepheids. © 2011. The American Astronomical Society. All rights reserved.

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