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While the population of America's public schools is becoming more diverse, the percentage of minority teachers is steadily decreasing. While over 44% of all students in America are minority, only 12-14% of teachers are minorities and less than 2% are African American males. The challenge for colleges of education is to recruit more African American male teachers. Therefore, this study was undertaken to explore the concept of grit and its impact on African American males entering the teaching profession.

In an environment of uncertain climatic change, there is an urgent need to develop robust reserve networks, i.e., networks that conserve species across multiple climatic futures. Using climatic envelopes based on multiple future climatic scenarios, we first estimate the impacts that these scenarios might have on the distributions of 63 native tree species in the Province of Ontario. Next, an optimization model is applied to expand an existing system of reserves in this province by determining the minimum number of optimal locations for additional reserves both with and without the need for migration. The optimization model formulated differs from previous work in that it meets the need for present and future distributions to occur in the same reserve and accommodates multiple differing climate change scenarios rather than a single scenario. The reserve selection approach described here can be applied anywhere that species' distributions and environmental grids are available. Although this approach is designed to produce a robust solution to the uncertainties over future climatic scenarios, it does not eliminate these uncertainties because the proposed solutions inherit the uncertainties of the global climate change models. Resume: Dans un contexte d'incertitude face au changement climatique, il est urgent de mettre sur pied des reseaux robustes de reserves, c.-a-d. des reseaux qui preservent les especes face a un eventail d'avenirs climatiques plausibles. A l'aide d'enveloppes climatiques basees sur un ensemble de scenarios climatiques futurs, nous estimons d'abord l'impact que ces scenarios pourraient avoir sur la repartition geographique de 63 especes indigenes arborescentes dans la province d'Ontario. Ensuite, un modele d'optimisation est applique pour etendre le systeme existant de reserves dans cette province en determinant le nombre minimum de localisations optimales pour des reserves additionnelles avec et sans besoin de migration. Le modele d'optimisation qui a ete developpe differe des modeles precedents en ce qu'il repond a la necessite que les repartitions actuelle et future se retrouvent dans la meme reserve et qu'il tient compte de plusieurs scenarios de changement climatique differents plutot que d'un seul. L'approche presentee ici pour choisir des reserves peut etre appliquee partout ou la repartition des especes et des grilles environnementales sont disponibles. Bien que cette approche soit concue pour produire une solution robuste aux incertitudes inherentes aux scenarios climatiques futurs, elle n'elimine pas ces incertitudes parce que les solutions proposees heritent des incertitudes des modeles de changement climatique planetaire. [Traduit par la Redaction], Introduction Since climate is the primary force determining the presence and absence of plant species and associated communities within a region, large shifts in the distribution of tree species can [...]

Optimal breeding zones were developed for white spruce (Picea glauca (Moench) Voss) in Ontario under present and future climate conditions to examine potential shifts due to climate change. These zones were developed by (i) determining a set of candidate breeding zones based on the relationship between measured performance variables and climate and (ii) employing a decision support model to select subsets of breeding zones that maximize geographic coverage subject to a constraint on the maximum number of zones. Current optimal breeding zones were based on 1961-1990 climate normals, and future breeding zones were based on three general circulation model (CGCM2, HADCM3, and CSIRO) predictions of 2041-2070 climate. Based on a maximum adaptive distance of 2.0 least significant difference values between sites within zones, 14 zones were required to cover the Ontario range of white spruce for the 1961-1990 data. Compared with breeding zones of other boreal conifers, current optimal breeding zones for white spruce were quite large, spanning up to 3° latitude and 10°-12° longitude and indicating large distances of effective seed transfer. Of the three general circulation models used to simulate future climate, HADCM3 B2 and CGCM2 B2 predicted 2041-2070 breeding zones that largely coincide with 1961-1990 zones. In contrast, CSIRO B2 indicated much narrower 2041-2070 breeding zones. Resume: Les auteurs ont determine des zones optimales damelioration de lepinette blanche (Picea glauca (Moench) Voss) en Ontario pour les conditions climatiques actuelles et futures afin dexaminer les modifications potentielles dues aux changements climatiques. Ces zones ont ete obtenues (i) en determinant un ensemble de zones candidates damelioration a partir des relations entre les variables de performance et le climat et (ii) en utilisant un modele daide a la decision pour choisir un sous-ensemble de zones damelioration maximisant la couverture geographique avec une contrainte quant au nombre maximal de zones. Les zones optimales actuelles damelioration etaient basees sur les normales climatiques de la periode 1961-1990. Les zones futures damelioration etaient basees sur les predictions de trois modeles de circulation generale (GCM2, HADCM3 et CSIRO) pour le climat de la periode 2041-2070. Avec la restriction que la distance reliee a ladaptation ne depasse pas deux fois la plus petite difference significative entre deux sites dune meme zone, 14 zones sont apparues necessaires pour representer adequatement la distribution de lepinette blanche en Ontario durant la periode 1961-1990. Comparativement aux zones damelioration des autres coniferes boreaux, les zones optimales actuelles dame--lioration pour lepinette blanche etaient relativement grandes, couvrant jusqua 3° de latitude et de 10° a 12° de longitude, impliquant de grandes distances pour le transfert effectif des semences. Parmi les trois modeles de circulation generale utilise s pour simuler le climat futur pour la periode 2041-2070, les modeles HADCM3 B2 et CGCM2 B2 predisaient des zones damelioration largement similaires a celles de la periode 1961-1990. A loppose, le modele CSIRO B2 predisait des zones damelioration beaucoup plus etroites. [Traduit par la Redaction], Introduction Ensuring local adaptation of planted sources is of paramount concern in forest regeneration and tree improvement practices. Tree seeds planted outside of their environmental tolerance limits are unable to [...]

Height, diameter, and survival data were obtained from 20 range-wide black spruce (Picea mariana (Mill.) BSP) provenance trials established from 1973 to 1977. Population response functions based on February minimum temperatures were developed for 23 Ontario and Great Lakes states provenances to predict climate values maximizing height growth for individual seed sources. Site transfer functions based on February maximum temperatures and May maximum temperatures were developed for five test sites to predict climate values maximizing height growth for test locations. Contour lines representing optimal performance were fitted to current (1961-1990) and future (2041-2070) climate grids. For black spruce seed sources from the east of Lake Superior and Lake Huron, optimal height growth was achieved between 45° and 47°N; for the western sources optimal performance moved north between 46° and 48°N. In eastern Ontario, height growth of northern sources may increase with transfer to warmer environments and with future temperature increases. Central sources are currently growing at or close to optimum and will be negatively affected by increased future temperatures. Southern sources may currently benefit from transfer to cooler environments, and the effects of global warming may cause significant height growth loss and the potential extirpation of local populations. Des donnees de hauteur, de diametre et de survie ont ete obtenues pour 20 tests de provenances d' epinette noire (Picea mariana (Mill.) BSP) etablis entre 1973 et 1977 a travers l'aire naturelle de repartition de cette essence. Des fonctions de response de la population bases sur la temperature minimum en fevrier ont ete developpees pour 23 provenances de l'Ontario et des Grands Lacs afin de predire les valeurs du climat qui maximisent la croissance en hauteur de provenances individuelles. Des fonctions de transfert de site basees sur la temperature maximum en fevrier et la temperature maximum en mai ont ete developpees pour cinq sites d'essai afin de predire les valeurs du climat qui maximisent la croissance en hauteur dans les sites d'essai. Des lignes de contour correspondant a la performance optimale ont ete ajustees aux grilles climatiques actuelles (1961-1990) et futures (2041-2070). Dans le cas des provenances d'epinette noire de l'est des lacs Superieur et Huron, la croissance optimale en hauteur survenait entre le 45 et 47°N; dans le cas des provenances de l'ouest, la performance optimale survenait plus au nord entre le 46 et 48° N. Dans l'est de l'Ontario, la croissance en hauteur des provenances nordiques pourrait augmenter en effectuant un transfert vers des milieux plus chauds ou a cause de l'augmentation future de la temperature. Les provenances centrales croissent presentement de facon optimale ou presque et seront affectees negativement par l'augmentation future de la temperature. Les provenances meridionales pourraient des maintenant beneficier d'un transfert vers des milieux plus froids et les effets du rechauffement global pourraient engendrer une perte significative de croissance en hauteur et la disparition potentielle des populations locales. [Traduit par la Redaction], Introduction The primary force determining the vegetation of a region is climate--in particular temperature, precipitation, and seasonal variation (Adams 2007). Over the next century, increasing concentrations of atmospheric carbon dioxide [...]

Abstract: Height, diameter, and survival data were obtained from 16 rangewide jack pine provenance trials in eastern Canada and the United States. Climate data for each seed source and test [...]

Abstract: The focal point seed zone methodology determines spatially explicit areas of adaptive similarity for any selected geographic point and is used to match seed sources and planting sites. A [...]

Abstract: To investigate the genetic variation of trembling aspen (Populus tremuloides Michx.) in ecophysiological responses to [C[O.sub.2]] elevation, 1-year-old seedlings of four provenances (three families per provenance) from northwestern Ontario [...]

Background Postural tachycardia syndrome (PTS) is a novel identified sequela of COVID-19 infection. This observational study describes clinical presentation, testing, and treatment response in seven patients diagnosed with PTS following COVID-19 infection. Case summary A total of seven active patients (three collegiate athletes, one recreational athlete, two registered nurses, one hospitality employee), age 24 ± 6 years, and six females were followed for a mean of 152 ± 105 days after contracting COVID-19. Tilt table was performed to establish the diagnosis. The most common presenting symptoms were palpitations (7/7), dyspnoea (6/7), and gastrointestinal complaints (5/7). One patient required hospitalization for symptom management. The mean latency of PTS onset following COVID-19 was 21 ± 15 days. Electrocardiograms (ECGs) demonstrated sinus rhythm in all patients, one with resting sinus tachycardia. Echocardiogram demonstrated normal systolic and diastolic left ventricular function in all patients. On tilt table testing, baseline heart rate (HR) was 72 ± 12 with maximum HR reaching 136 ± 13. Six of seven patients failed to respond to supportive therapy alone, and two patients failed medical management with ivabradine, midodrine, and/or metoprolol. Of three severely symptomatic patients, two demonstrated some degree of clinical recovery with intravenous immunoglobulin (IVIG). Discussion This novel case series describes the development of PTS in the context of COVID-19 infection. Severity of symptoms and response to treatment was heterogeneous. Interestingly, patients were poorly responsive to traditional PTS treatments, but IVIG showed potential as a possible therapeutic strategy for refractory PTS in two patients, particularly following COVID-19 infection. [ABSTRACT FROM AUTHOR]