Effect of Rotation Age on Lumber Grade Yield, Bending Strength and Stiffness in Jack Pine (Pinus Banksiana Lamb.) Natural Stands

The effects of rotation age on lumber visual grade yield and lumber bending properties were studied on 142 jack pine trees sampled in three stands located in Timmins, Ontario. The stands, aged 50, 73, and 90 years were all naturally established after forest fires. The visual grading of a total of 1720 lumber pieces showed that the 50-yr-old stand produced a slightly lower Select Structural grade yield (36.1%) compared to the older stands (73 yr 42.9% and 90 yr 39.3%). When No. 2 and Better grades were combined, the 50-yr-old stand resulted in the lowest volume yield (88.2%), whereas the proportions of No. 2 and Better for the 73- and 90-yr-old stands were comparable (93.0 and 92.6%, respectively). Downgrades due to decay were much higher in the 90-yr-old stand (20.6%) than in the 73- and 50-yr-old stands (5.2% and 0%, respectively). Regarding stand productivity, the 50-yr-old stand showed the highest annual stand increment of 5.25 m3/ha/year, compared to 3.82 and 3.21 for the 73- and 90-yr-old stands, respectively. The visual grading of 782 board pieces showed no effect of stand age on board quality. In the 90-yr-old trees, wood density decreased steadily from butt to top for all the diameter classes studied (12-30 cm).The study showed that rotation age had a significant impact on lumber bending properties. The lumber bending properties for the 50-yr-old stand were significantly lower than those of the 73- and 90-yr-old stands. The lumber strength (MOR) and lumber stiffness (MOE) values for the 50-yr-old stand were about 16% lower and 19-16% lower than those of the 73- and 90-yr-old stands, respectively. However, no significant differences in lumber bending properties were found between the two older stands. From the viewpoint of lumber properties, a moderate rotation age of about 70 years is preferred in jack pine

Within-Tree Variability of Wood Color in Paper Birch in Québec

Color variations in paper birch wood were examined in boards sawn from sawlogs from 168 trees harvested from two different stands. Approximately 2250 boards were sawn from the logs. The within-tree variability was considered by looking at the effect of log quality and log height class on board color. Results show that neither the log quality nor the log height class had a significant effect on the proportion of discolored wood on the surface of the board. However, these log parameters had an effect on the wood colorimetric variables. Log position in the tree was found to significantly influence sapwood yellowness as well as discolored wood luminosity and redness. Log quality on the other hand significantly influenced only one colorimetric factor, sapwood redness

Variability of Wood Color in Paper Birch in Québec

Color variability of paper birch (Betula papyrifera Marsh.) wood at the tree level was examined in this article. Tree age, dimension, and vigor were expected to influence the proportion of discolored wood in paper birch boards; older, larger, and less vigorous trees were assumed to produce boards with higher proportions of discolored wood. The color analysis was performed on approximately 2250 boards produced from 168 paper birch trees harvested in two different stands from which only logs of sawing quality were used. An industrial scanner was used to digitize the boards and obtain colorimetric information. Results show that tree diameter and vigor significantly influenced the proportion of discolored wood in boards, whereas the effect of tree age did not have a significant influence in the model. An average area of 32.4% of discolored wood was obtained when considering all boards. Less vigorous trees showed a mean area of 45.32%, whereas middle-vigor and most-vigorous trees had mean areas of 30.78 and 15.47%, respectively. The colorimetric values were mainly affected by tree age and diameter, but these effects were variable for every colorimetric parameter. The analysis of the random effects demonstrated that most of the total random variance of the dependent factors came from the between-board, between-tree, and, to a lesser extent, between-log variation. These findings suggest that favoring shorter rotations would help produce trees with lower proportions of discolored wood

Réappropriation de l’artisanat traditionnellement féminin par le dessin : petits tracés vers une écriture féminine

Ce mémoire de maîtrise accompagne les oeuvres réunies sous l’exposition Manière de faire | Manière de voir, présentée au Centre national d’exposition du 7 décembre 2017 au 14 janvier 2018. Dans notre société, certaines pratiques artisanales sont associées à un genre (féminin ou masculin). C’est, par exemple, le cas du tricot, de la broderie et du tissage qui sont tous des savoir-faire dits féminins. M’intéressant à cette association entre genre et pratique, de même qu’à la place du savoir-faire tant dans les beaux-arts (le dessin, dans le cas présent) qu’au sein des arts appliqués, j’ai fait de l’artisanat traditionnellement féminin le sujet principal de ma recherche en pratique artistique. C’est à travers une approche du dessin basée sur des techniques traditionnelles ainsi que sur la sensibilité et la fragilité du trait fait par la main que je m’intéresse au genre féminin, et cela, avec une approche féministe. L’objectif de ma maîtrise est le suivant : développer, par l’intermédiaire du dessin, un langage plastique issu de la réappropriation de l’artisanat traditionnellement féminin, et ce, de manière à affirmer ma vision d’une écriture féminine. De surcroit, ma recherche s’articule autour des sous-objectifs suivants : 1 — Exploiter une thématique genrée féminine depuis une perspective féministe; 2 — Valoriser, au sein de l’oeuvre d’art, l’artisanat traditionnellement féminin comme héritage culturel; 3 — Mettre à profit le savoir-faire technique, dans ma pratique du dessin, afin d’enrichir l’oeuvre. Abordée depuis une approche autoesthétique, la présente réflexion écrite est le résultat d’un travail de contextualisation (théorique et artistique) et d’analyse du corpus d’oeuvres produit. Le concept féministe d’écriture féminine, élaboré par les différentialistes Hélène Cixous et Luce Irigaray, est le point culminant de mon travail écrit. L’actualisation par le dessin que je propose de ce concept, issu de la linguistique, m’est possible grâce à une démarche d’élaboration de mon positionnement féministe en tant qu’artiste, laquelle occupe une place importante au sein de mon mémoire. Ma posture féministe résulte d’un collage de diverses pensées théoriques (différentialiste, constructivisme, éthique du care et postmoderne). Elle est caractérisée par un désir de valoriser, non pas le sexe féminin (la femme), mais plutôt certaines pratiques, certaines formes ou certaines valeurs qui sont genrées féminines, et ce, par le faire artistique. Le résultat est conçu selon la perspective que l’art qui touche le politique doit rechercher un équilibre entre la valeur accordée au contenant (la facture de l’oeuvre) et celle accordée au contenu (le sens). En plus des notions de savoir-faire et de féminisme, celles d’héritage, de tradition et d’identité relative à un genre sont abordées dans mes dessins qui intègrent la représentation de l’artisanat traditionnellement féminin. De plus, le travail de trois artistes femmes, chez qui j’ai perçu des préoccupations semblables, est présenté de manière à mettre l’accent sur ce qui relie nos pratiques. Ces artistes sont : Nadia Myre, Ghada Amer et Annette Messager

Multivariate consistency of resting-state fMRI connectivity maps acquired on a single individual over 2.5 years, 13 sites and 3 vendors

Studies using resting-state functional magnetic resonance imaging (rsfMRI) are increasingly collecting data at multiple sites in order to speed up recruitment or increase sample size. The main objective of this study was to assess the long-term consistency of rsfMRI connectivity maps derived at multiple sites and vendors using the Canadian Dementia Imaging Protocol (CDIP, www.cdip-pcid.ca). Nine to 10 min of functional BOLD images were acquired from an adult cognitively healthy volunteer scanned repeatedly at 13 Canadian sites on three scanner makes (General Electric, Philips and Siemens) over the course of 2.5 years. The consistency (spatial Pearson’s correlation) of rsfMRI connectivity maps for seven canonical networks ranged from 0.3 to 0.8, with a negligible effect of time, but significant site and vendor effects. We noted systematic differences in data quality (i.e. head motion, number of useable time frames, temporal signal-to-noise ratio) across vendors, which may also confound some of these results, and could not be disentangled in this sample. We also pooled the long-term longitudinal data with a single-site, short-term (1 month) data sample acquired on 26 subjects (10 scans per subject), called HNU1. Using randomly selected pairs of scans from each subject, we quantified the ability of a data-driven unsupervised cluster analysis to match two scans of the same subjects. In this “fingerprinting” experiment, we found that scans from the Canadian subject (Csub) could be matched with high accuracy intra-site (>95% for some networks), but that the accuracy decreased substantially for scans drawn from different sites and vendors, even falling outside of the range of accuracies observed in HNU1. Overall, our results demonstrate good multivariate stability of rsfMRI measures over several years, but substantial impact of scanning site and vendors. How detrimental these effects are will depend on the application, yet our results demonstrate that new methods for harmonizing multisite analysis represent an important area for future work

A rehabilitation program to increase balance and mobility in ataxia of Charlevoix-Saguenay: An exploratory study

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is characterized by balance impairment and mobility limitations, which both increase the risk of falling. The objective of this study was to explore the effects of a rehabilitation program aimed at increasing trunk and lower limb motor control on balance and walking abilities, and accomplishment of activities of daily living. In this exploratory study, a group-supervised rehabilitation program was performed three times a week for 8 weeks (two sessions at a rehabilitation gym and one pool session). Outcome measures included the Ottawa Sitting Scale, Berg Balance Scale, modified Activities-specific Balance Confidence Scale, 30-Second Chair Stand Test, 10-Meter Walk Test, Barthel Index, and Scale for the Assessment and Rating of Ataxia. Significant improvements in balance, trunk control, maximal and self-selected walking speed difference, ataxia severity and accomplishment of specific activities of daily living were noted for the whole group at the end of the program. At the individual level, all participants improved beyond the standard error of measurement in at least two outcome measures. Also, most participants reported many perceived improvements related to balance, posture and functional mobility. This study provides encouraging results on the effects of a rehabilitation program for ambulatory people with ARSACS. Group intervention could have a positive impact on their daily lives and improve the health care service offered to this population. Future studies with larger sample sizes including control groups and other forms of ataxia are necessary to validate our results to generalize them

Explanatory factors of dynamic balance impairment in myotonic dystrophy type 1

Introduction/Aims Myotonic dystrophy type 1 (DM1) is a neuromuscular disease affecting many systems and for which muscle weakness is one of the cardinal symptoms. People with DM1 also present with balance-related impairments and high fall risk. The aim of this study was to explore explanatory factors of dynamic balance impairment in the DM1 population. Methods A secondary analysis of data collected as part of a larger study was performed. The Mini Balance Evaluation System Test (Mini-BESTest) was used to assess dynamic balance. Age, sex, and CTG repeat length in blood were retrieved from medical records and research files. The maximal isometric muscle strength of five lower limb muscle groups (hip flexors and extensors, knee flexors and extensors, and ankle dorsiflexors) was quantitatively assessed as well as fatigue. Standard multiple regression analysis was used. Results Fifty-two individuals (31 men) aged between 24 and 81 years were included. The final model explains 65.9% of the balance score; ankle dorsiflexor muscle strength was the strongest explanatory factor, followed by CTG repeat length, age and fatigue to a lesser extent. Discussion Dynamic balance is impaired in people with DM1. Results of this study suggest that rehabilitation interventions aimed at improving strength of the ankle dorsiflexors and managing fatigue could help to improve dynamic balance in this specific population

Measurement variability following MRI system upgrade

Major hardware/software changes to MRI platforms, either planned or unplanned, will almost invariably occur in longitudinal studies. Our objective was to assess the resulting variability on relevant imaging measurements in such context, specifically for three Siemens Healthcare Magnetom Trio upgrades to the Prismafit platform. We report data acquired on three healthy volunteers scanned before and after three different platform upgrades. We assessed differences in image signal (contrast-to-noise ratio (CNR)) on T1-weighted images (T1w) and fluid-attenuated inversion recovery images (FLAIR); brain morphometry on T1w image; and small vessel disease (white matter hyperintensities; WMH) on FLAIR image. Prismafit upgrade resulted in higher (30%) and more variable neocortical CNR and higher brain volume and thickness mainly in frontal areas. A significant relationship was observed between neocortical CNR and cortical volume. For FLAIR images, no significant CNR difference was observed, but WMH volumes were significantly smaller (-68%) after Prismafit upgrade, when compared to results on the Magnetom Trio. Together, these results indicate that Prismafit upgrade significantly influenced image signal, brain morphometry measures and small vessel diseases measures and that these effects need to be taken into account when analyzing results from any longitudinal study undergoing similar changes

COMPARING GC×GC-TOFMS-BASED METABOLOMIC PROFILING AND WOOD ANATOMY FOR FORENSIC IDENTIFICATION OF FIVE MELIACEAE (MAHOGANY) SPECIES

Illegal logging and associated trade have increased worldwide. Such environmental crimes represent a major threat to forest ecosystems and society, causing distortions in market prices, economic instability, ecological deterioration, and poverty. To prevent illegal imports of forest products, there is a need to develop wood identification methods for identifying tree species regulated by the Convention on International Trade in Species of Wild Fauna andFlora in Trade (CITES) and other look-alike species. In this exploratory study, we applied metabolomic profiling of five species (Swietenia mahagoni, Swietenia macrophylla, Cedrela odorata, Khaya ivorensis, and Toona ciliata) using two-dimensional gas chromatog- raphy combined with time-of-flight mass spectrometry (GC3GC-TOFMS). We also performed qualitative, quantitative (based on the measurement of vessel area, tangential vessel lumina diameter,vessel element length, ray height, and ray width), and machine-vision aided (XyloTron) wood anatomy on a subsample of wood specimens to explore thepotential and limits of each approach. Fifty dried xylaria wood specimens were ground, extracted with methanol, and subsequently analyzed by GC3GC-TOFMS. In this study, the four genera could easily be identified using qualitative wood anatomy and chemical profiling. At the spe- cies level, Swietenia macrophylla and Swietenia mahagoni specimens were found to share many major metabolites and could only be differentiated after feature selection guided by cluster resolution (FS-CR) and visualization using Principal Component Analysis (PCA). Expectedly, specimens from the two Swiete- nia spp. could not be distinguished based on qualitative wood anatomy. However, significant differences in quantitative anatomical features were obtained for these two species. Excluding T. ciliata that was not included in the reference database of end grain images at the time of testing (2021), the XyloTron could successfully identify the majority of the specimens to the right genus and 50% of the specimens to the right species. The machine-vision tool was particularly successful at identifying Cedrela odorata samples, where all samples were correctly identified. Despite the limited number of specimens available for thisstudy, our preliminary results indicate that GC3GC-TOFMS-based metabolomic profiles could be used as comple- mentary method to differentiate CITES-regulated wood specimens at the genus and species levels.