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Disturbances such as fire and harvesting shape forest dynamics and must be accounted for when modelling forest properties. However, acquiring timely disturbance information for all of Canada's large forest area has always been challenging. Therefore, we developed an approach to detect annual forest change resulting from fire, harvesting, or flooding using Moderate Resolution Imaging Spectroradiometer (MODIS) imagery at 250 m spatial resolution across Canada and to estimate the within-pixel fractional change (FC). When this approach was applied to the period from 2000 to 2011, the accuracy of detection of burnt, harvested, or flooded areas against our validation dataset was 82%, 80%, and 85%, respectively. With FC, 77% of the area burnt and 82% of the area harvested within the validation dataset were correctly identified. The methodology was optimized to reduce the commission error but tended to omit smaller disturbances as a result. For example, the omitted area for harvest blocks greater than 80 ha was less than 14% but increased to between 38% and 50% for harvest blocks of 20 to 30 ha. Detection of burnt and harvested areas in some regions was hindered by persistent haze or cloud cover or by insect outbreaks. All resulting data layers are available as supplementary material. Key words: boreal forest, National Burned Area Composite, remote sensing, regression tree, decision tree, change detection. Les perturbations telles que le feu et la coupe faconnent la dynamique forestiere et doivent etre prises en compte lorsqu'on modelise les proprietes de la foret. Cependant, l'acquisition rapide de l'information au sujet des perturbations pour l'ensemble des vastes superficies de foret du Canada a toujours presente un defi. Nous avons par consequent developpe une approche pour detecter les changements annuels de la foret dus au feu, a la coupe ou aux inondations en utilisant l'imagerie MODIS avec une resolution spatiale de 250 m partout au Canada et pour estimer le changement fractionnel (FC) a l'echelle du pixel. Lorsque appliquee a la periode allant de 2000 a 2011, la precision de la detection des superficies brulees, coupees ou inondees sur la base de notre jeu de donnees de validation atteignait respectivement 82,80 et 85%. Avec le FC, 77% des superficies brulees et 82% des superficies coupees ont ete correctement identifiees dans le jeu de donnees de validation. La methodologie a ete optimisee pour reduire les erreurs dues a la detection de faux changements avec le resultat cependant qu'elle a tendance a ne pas detecter les plus petites perturbations. Par exemple, les superficies non detectees pour les aires de coupe plus grandes que 80 ha etaient inferieures a 14%, mais atteignaient entre 38 et 50% pour les aires de coupe de 20 a 30 ha. La detection des superficies brulees et coupees etait difficile dans certaines regions du a la brume ou au couvert nuageux persistant, ou par les epidemies d'insecte. Toutes les couches de donnees resultantes sont disponibles dans la section Materiel supplementaire. [Traduit par la Redaction] Mots-cles: foret boreale, Composite nationale des superficies brulees, teledetection, arbre de regression, arbre de decision, detection de changement., Introduction The managed forests of Canada cover approximately 229 Mha (Environment Canada 2012). Much of this area is in the boreal forest, which is characterized by slow growth and significant [...]

Long-term changes in the Normalized Difference Vegetation Index (NDVI) have been evaluated in several studies but results have not been conclusive due to differences in data processing as well as the length and time of the analysed period. In this research a newly developed 1 km Advanced Very High Resolution Radiometer (AVHRR) satellite data record for the period 1985-2006 was used to rigorously evaluate NDVI trends over Canada. Furthermore, climate and land cover change as potential causes of observed trends were evaluated in eight sample regions. The AVHRR record was generated using improved geolocation, cloud screening, correction for sun-sensor viewing geometry, atmospheric correction, and compositing. Results from both AVHRR and Landsat revealed an increasing NDVI trend over northern regions where comparison was possible. Overall, 22% of the vegetated area in Canada was found to have a positive NDVI trend based on the Mann-Kendal test at the 95% confidence level. Of these, 40% were in northern ecozones. The mean absolute difference of NDVI measurements between AVHRR and Landsat data was <7%. When compared with results from other studies, similar trends were found over northern areas, while in southern regions the results were less consistent. Local assessment of potential causes of trends in each region revealed a stronger influence of climate in the north compared to the south. Southern regions with strong positive trends appeared to be most influenced by land cover change. [ABSTRACT FROM AUTHOR]

An algorithm is presented for automated detection–delineation of coniferous tree regeneration that combines strategies of several existing algorithms, including image processing to isolate conifer crowns, optimal image scale determination, initial crown detection, and crown boundary segmentation and refinement. The algorithm is evaluated using 6-cm pixel airborne imagery in operational regeneration conditions typically encountered in the boreal forest 5–10 years after harvest. Detection omission and commission errors as well as an accuracy index combining both error types were assessed on a tree by tree basis, on an aggregated basis for each study area, in relation to tree size and the amount of woody competition present. Delineation error was assessed in a similar manner using field-measured crown diameters as a reference. The individual tree detection accuracy index improved with increasing tree size and was >70% for trees larger than 30 cm crown diameter. Crown diameter absolute error measured from automated delineations was <23%. Large crown diameters tended to be slightly underestimated. The presence of overtopping woody competition had a negligible effect on detection accuracy and only reduced estimates of crown diameter slightly. [ABSTRACT FROM AUTHOR]

Climate can have direct and indirect effects on population dynamics via changes in resource competition or predation risk, but this influence may be modulated by density- or phase-dependent processes. We hypothesized that for ungulates, climatic conditions close to parturition have a greater influence on the predation risk of neonates during population declines, when females are already under nutritional stress triggered by food limitation. We examined the presence of phase-dependent climate-predator (PDCP) interactions on neonatal ungulate survival by comparing spatial and temporal fluctuations in climatic conditions, cause-specific mortality and per capita resource limitation. We determined cause-specific fates of 1384 caribou (Rangifer tarandus) from 10 herds in Newfoundland, spanning more than 30 years during periods of numerical increase and decline, while exposed to predation from black bears (Ursus americanus) and coyotes (Canis latrans). We conducted Cox proportional hazards analysis for competing risks, fit as a function of weather metrics, to assess pre- and post-partum climatic influences on survival on herds in population increase and decline phases. We used cumulative incidence functions to compare temporal changes in risk from predators. Our results support our main hypothesis; when caribou populations increased, weather conditions preceding calving were the main determinants of cause-specific mortality, but when populations declined, weather conditions during calving also influenced predator-driven mortality. Cause-specific analysis showed that weather conditions can differentially affect predation risk between black bears and coyotes with specific variables increasing the risk from one species and decreasing the risk from the other. For caribou, nutritional stress appears to increase predation risk on neonates, an interaction which is exacerbated by susceptibility to climatic events. These findings support the PDCP interactions framework, where maternal body condition influences susceptibility to climate-related events and, subsequently, risk from predation., (© 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.)

Objective: To determine the efficacy of combined endoscopic medial and external lateral orbital decompression for the treatment of compressive optic neuropathy (CON) in thyroid eye disease (TED)., Design: A retrospective review of all patients undergoing combined surgical orbital decompression for CON between 2000 and 2010 was conducted., Participants: Fifty-nine eyes of 34 patients undergoing combined surgical orbital decompression for CON., Methods: Clinical outcome measures included visual acuity, Hardy-Rand-Rittler (HRR) colour plate testing, relative afferent pupillary defect, intraocular pressure measurement, and Hertel exophthalmometry. A CON score was calculated preoperatively and postoperatively based on the visual acuity and the missed HRR plates. A higher CON score correlates with more severe visual dysfunction., Results: All patients had improvement of their optic neuropathy after surgical decompression. CON score was calculated for 54 eyes and decreased significantly from a mean of 13.2 ± 10.35 preoperatively to a mean of 8.51 ± 10.24 postoperatively (p < 0.0001). Optic neuropathy was completely resolved in 93.22% (55/59 eyes). Eighteen of 34 patients (52.94%) experienced development of new-onset postoperative strabismus that required subsequent surgical intervention., Conclusions: Endoscopic medial combined with external lateral orbital decompression is an effective technique for the treatment of TED-associated CON., (© 2013 Canadian Ophthalmological Society Published by Canadian Ophthalmological Society All rights reserved.)

Objectives/hypothesis: To evaluate the facial nerve outcome postoperatively of schwannoma vestibular surgery with a stimulation threshold (ST) lower than 0.05 mA., Study Design: Retrospective chart review., Methods: A total of 106 patients had undergone schwannoma vestibular surgery between 2002 and 2008 in a tertiary center. The ST near the brainstem was obtained after the tumor removal. Facial nerve function was evaluated according to the House-Brackmann (HB) scale immediately postoperatively and at 1 year. The results were compared among the different STs used: <0.05 mA, 0.05 mA, and >0.05 mA., Results: There were 50 patients who had an ST <0.05 mA, 45 patients who had an ST of 0.05 mA, and 11 patients who had a ST >0.05 mA. Immediately postoperatively, for all of these groups we had a preservation of facial nerve function (HB I-II) in 94%, 80%, and 36% of patients, respectively (P < .0001). At 1 year in the same groups the preservation of the facial nerve function was 100%, 93%, and 82% of patients, respectively (P < .01)., Conclusions: A proximal ST of <0.05 mA is a better predictor of facial nerve function immediately postoperatively., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.)

Aims: First, to assess the outcomes of endoscopic and external lateral orbital decompression in patients with dysthyroid orbitopathy. Second, to establish a correlation between the percentage of postoperative diplopia and the technique used., Methods: A retrospective review of 40 patients (73 eyes) who underwent endoscopic medial orbital decompression and external lateral orbital decompression between 1997 and 2003 at the Hôpital Enfant-Jesus in Quebec City. Some of these patients also had an inferior endoscopic decompression. All patients had exophthalmos. The principal indications for surgery were 42 eyes with compressive optic neuropathy, 13 eyes with other ocular disorders, and 18 eyes with exophthalmos only. All patients with neuropathy underwent endoscopic decompression of the optic canal., Results: All patients had satisfactory improvement of their ocular pathology. Optic neuropathy was completely resolved in 92.85% (39 of 42 eyes). In patients who did not have preoperative diplopia (26), diplopia developed in 70% (14 of 20) of those who underwent medial and inferior decompression compared with 16.6% (1 of 6) of patients who underwent medial decompression only., Conclusion: Endoscopic medial orbital decompression is very effective in resolving compressive optic neuropathy. Preservation of the orbital floor, when the degree of exophthalmos allows, reduces the incidence of postoperative diplopia.

Vascular malformations (angiomas) represent 1% of all pathologies of the temporal bone, including those of the cerebellopontine angle (CPA). We report six new cases of angiomas and compare them to the 48 cases listed in the literature published since 1949. Angiomas develop more frequently in the internal auditory canal (IAC) and at the geniculate ganglion (GG). When present in the IAC, rapidly progressive hearing loss is found in 88% of the patients reported in the literature and in 100% of patients in our series; facial nerve dysfunction is found in 72% and 60% of cases, respectively. The average tumour size is less than 10 mm. Acoustic neuroma, the most frequent tumour of this area, causes a slowly progressive sensorineural hearing loss in 75% of cases and facial weakness in 0.8%, according to the literature. Only 10% of acoustic neuromas measure less than 10 mm. Angiomas differ from acoustic neuromas in their rapid onset of sensorineural deafness and much greater incidence of facial nerve dysfunction despite a smaller tumour size.

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant transmitted condition seen mainly in the French Canadian population. Twenty-one patients with an established diagnosis of this rare disease underwent inferior constrictor myotomy. All patients were evaluated clinically and 12 of them underwent pharyngoesophageal manometric evaluation both preoperatively and postoperatively. All patients presented with severe oropharyngeal dysphagia and frequent aspiration together with pharyngooral and pharyngonasal regurgitation. Our results showed that all symptoms were significantly improved after inferior constrictor myotomy. Manometric assessment showed significant differences in pressure, duration and frequency of pharyngeal contraction when compared with a control group. After surgery pharyngeal contraction frequency was significantly lowered toward the normal level but other parameters of pharyngeal function remained unchanged. At the level of the upper esophageal sphincter, resting and closing pressure, relaxation time, relaxation and coordination were studied. There was no significant difference between control subjects and OPMD patients for these variables. Surgery significantly lowered the resting and closing pressure of the sphincter but did not modify significantly the other parameters.

The possibilities of bone graft to the face are multiple. After reviewing the anatomy and physiology of bone grafting, the authors present different types of cases illustrating some of these possibilities. Each case of malformation of the face presents problems in which bone grafting is often an elegant solution with or without osteotomies. After describing the principles and techniques used in these cases, the authors comment upon 26 personal cases using mostly the intraoral approach for laying bone around the face. Three out of 26 have developed postoperative infections but only one case has needed removal of part of the bone grafts. Their youngest patient was 12 years old.

Following a few European and American authors, we have undertaken tympano-ossicular homografts at the Hotel-Dieu de Quebec. The organization of the bank was achieved with many difficulties. We undertook our first surgical homografts in 1974, and 27 cases have since been performed. Our statistics are based on 19 cases. We obtained a perfect tympanic membrane in 17 cases, and 60 per cent of these have shown good improvement in hearing. This percentage is remarkable when one considers that we limited this procedure to cases for which all other techniques were bound to fail.