Classification, caractérisation et facteurs de variabilité spatiale des régimes hydrologiques naturels au Québec (Canada). Approche éco-géographique

Nous proposons onze nouvelles variables pour classifier, caractériser et analyser les facteurs de variabilité spatiale des régimes hydrologiques des affluents du fleuve Saint-Laurent au Québec. Ces variables se rapportent exclusivement aux débits mensuels et utilisent quatre (volume d’écoulement, période d’occurrence, durée et amplitude de variabilité intra-annuelle des débits) des cinq critères proposés par Richter et al. (1996) pour caractériser écologiquement les régimes hydrologiques.L’analyse en composantes principales de ces onze variables hydrologiques a permis d’extraire trois composantes principales significatives après rotation d’axes par la méthode varimax. La première composante principale est associée aux débits saisonniers hivernaux et aux mois d’occurrence des débits mensuels maximums et minimums. La seconde composante est associée aux débits saisonniers printaniers et au rapport entre ces débits et les débits estivaux. Enfin, la dernière composante est associée au coefficient d’immodération (rapport entre les débits mensuels maximums et minimums) et aux débits mensuels minimums. La variance totale expliquée par ces trois composantes, à part presqu’égale, est d’environ 83%. Sur la base des signes de notes factorielles sur les trois composantes principales, les 72 rivières analysées ont été groupées en huit régimes hydrologiques naturels non contigus dans l’espace. Les caractéristiques de chaque régime hydrologique ont été clairement définies.Quant aux facteurs environnementaux qui influencent la variabilité spatiale des régimes hydrologiques, il est apparu que les six variables hydrologiques associées aux trois composantes principales sont principalement influencées par la température de l’air ainsi que la superficie couverte par les forêts, les lacs et les marais.Several classifications of hydrologic regimes have already been proposed in Quebec. However, these classifications are exclusively based upon the magnitude of discharge (annual and monthly discharge, annual maximum and minimum discharge). This hydrologic parameter isn’t sufficient to describe the ecological hydrologic regime. Thus, Richter et al. (1996) suggested five fundamental characteristics to describe hydrologic regimes that regulate ecological processes in river ecosystems :1. The magnitude of the water condition at any given time. It is a measure of the availability or suitability of a habitat. It defines such habitat attributes as wetted area or habitat volume, or the position of the water table relative to wetland or riparian plant rooting zones.2. The timing of occurrence of particular water conditions can determine whether certain life-cycle requirements can influence the degree of stress or mortality associated with extreme water conditions such as flood or droughts.3. The frequency of occurrence of specific water conditions such as droughts or floods may be tied to reproduction or mortality events for various species, thereby influencing population dynamics.4. The duration of time over which a particular life-cycle phase can be completed or the degree to which stressful effects such as inundation or drought can accumulate.5. The rate of change (range) in water conditions may be related to the stranding of certain organisms along the water’s edge, in ponded depressions, or the ability of plant roots to maintain contact with phreatic water supplies.The application of these characteristics requires a daily discharge time series, but these data are not always available. To overcome this difficulty, we propose eleven new hydrological variables exclusively based upon monthly discharge data. These new variables describe four (magnitude, timing of occurrence, duration of time and the rate of change) of the five characteristics of hydrologic regimes suggested by Richter et al. (1996). The eleven new variables are as follows: seasonal discharge coefficients (%); monthly maximum and minimum discharge coefficients (%); median Julian day of occurrence of maximum monthly discharge; median Julian day of occurrence of monthly minimum discharge; spring and winter seasonal discharge ratios; spring and summer seasonal discharge ratios and monthly maximum and minimum discharge ratios.We have isolated, using principal component analysis (PCA), three significant principal components after varimax rotation. The first principal component was linked with the magnitude of winter discharge and the timing of monthly maximum and minimum discharge. The second principal component was associated with the magnitude of spring seasonal discharge and the spring and summer seasonal discharge ratio. The third component was linked with the coefficient of immoderation (monthly maximum/minimum discharge ratio) and the magnitude of monthly minimum discharge. The three principal components explain, almost weight for weight, about 83% of the total variance. On the basis of signs of loadings for these three components, 72 rivers were analysed and grouped into eight natural hydrologic regimes that are not geographically contiguous. For example, the first hydrologic regime was characterized by high winter discharge (> 12%), timing of monthly maximum discharge in April, high summer discharge (> 54%), high spring and summer seasonal discharge ratios (> 3.5), high monthly maximum and minimum discharge (> 12) and low monthly minimum discharge ( 0ºC. The correlation analysis revealed the following mean results:- The winter seasonal discharge was influenced by the forest surface area (negative correlation) and both annual and seasonal temperature (positive correlation).- The timing of the monthly maximum discharge was influenced by the length of rivers (positive correlation), the forest and lake surface area (positive correlation) and both annual and seasonal temperatures (negative correlation).- The spring seasonal discharge was influenced by the length of rivers (negative correlation), the mean basin slope (positive correlation), the forest surface area (positive correlation), the lake surface area (negative correlation), the annual precipitation (negative correlation) and the winter and summer seasonal temperature (negative correlation).- The spring and summer seasonal discharge ratio was negatively correlated with the drainage basin, the length of rivers, the mean basin drainage, the annual precipitation and the number of winter days with temperature > 0ºC, but was positively correlated with annual and seasonal temperature.- The monthly maximum and minimum discharge was positively correlated with forest surface area but negatively correlated with lake surface area, annual and seasonal temperature.- The monthly minimum discharge was negatively correlated with forest surface area but positively correlated with annual and seasonal discharge.From this correlation analysis, it appeared that temperature was the only factor that influenced the spatial variability of all hydrological variables, followed by forest and lake surface area. The influence of precipitation on this spatial variability was very weak

The Impact of the Purchaser Provider Funding Model inthe U.K. on the Independence of Persons with Disabilities:Implications for Canada

Through large-scale system restructuring, a number of jurisdictions around the world have adopted a purchaserprovider approach to the funding and delivery of health care services. In this model, a decision-making body, such as a regional board, is provided with a budget to purchase health care services on behalf of, and in response to the identified needs of a defined population. This paper reviews the purchaser provider funding model of the United Kingdom and comments on the impact of this system on the health needs of individuals with disabilities. Generally, the purchaser provider split in the U.K. appears to have resulted in greater fragmentation and inequity in care among the disabled population. The implications of the use of this type of funding method on individuals with disabilities residing in Canada are then discussed in relation to the Canadian Charter of Rights and Freedoms

Investigating microstructural variation in the human hippocampus using non-negative matrix factorization

In this work we use non-negative matrix factorization to identify patterns of microstructural variance in the human hippocampus. We utilize high-resolution structural and diffusion magnetic resonance imaging data from the Human Connectome Project to query hippocampus microstructure on a multivariate, voxelwise basis. Application of non-negative matrix factorization identifies spatial components (clusters of voxels sharing similar covariance patterns), as well as subject weightings (individual variance across hippocampus microstructure). By assessing the stability of spatial components as well as the accuracy of factorization, we identified 4 distinct microstructural components. Furthermore, we quantified the benefit of using multiple microstructural metrics by demonstrating that using three microstructural metrics (T1-weighted/T2-weighted signal, mean diffusivity and fractional anisotropy) produced more stable spatial components than when assessing metrics individually. Finally, we related individual subject weightings to demographic and behavioural measures using a partial least squares analysis. Through this approach we identified interpretable relationships between hippocampus microstructure and demographic and behavioural measures. Taken together, our work suggests non-negative matrix factorization as a spatially specific analytical approach for neuroimaging studies and advocates for the use of multiple metrics for data-driven component analyses

Exchange bias in GeMn nanocolumns: the role of surface oxidation

We report on the exchange biasing of self-assembled ferromagnetic GeMn nanocolumns by GeMn-oxide caps. The x-ray absorption spectroscopy analysis of this surface oxide shows a multiplet fine structure that is typical of the Mn2+ valence state in MnO. A magnetization hysteresis shift |HE|~100 Oe and a coercivity enhancement of about 70 Oe have been obtained upon cooling (300-5 K) in a magnetic field as low as 0.25 T. This exchange bias is attributed to the interface coupling between the ferromagnetic nanocolumns and the antiferromagnetic MnO-like caps. The effect enhancement is achieved by depositing a MnO layer on the GeMn nanocolumns.Comment: 7 pages, 5 figure

Pharmacogenetic GWAS meta-analysis of LDL cholesterol response to statins

Cardiolog

Exploring Children’s Insights about Participating in Recreational Activities with Horses and Farm Animals: Social Emotional Experiences and Belief in Animal Mind

Research continues to shed light on the impact of children’s interactions with horses in equine-assisted, learning, and therapeutic contexts. However, we know relatively less about the impact of children’s recreational activities with horses and a diversity of farm animals. What is needed is research that explores how recreational programs involving activities with horses and farm animals are perceived by the child participants themselves. This pilot study sought to explore the insights of children who participated in a nine-week recreational program involving activities with horses and farm animals, with a focus on children’s social emotional experiences and belief in animal mind, which involves attributing to animals the ability to think, feel, and experience emotions. Prior to beginning the nine-week program and upon its conclusion, we interviewed eight children (5 girls; 3 boys; aged 9 to 11 years) who were referred to the pro-gram because they were living in socioeconomically disadvantaged homes. Children responded to open-ended questions about their belief in animal mind and social emotional experiences. Salient themes in children’s responses prior to and following their participation in the program were identified using qualitative content analysis. Overall, children’s responses revealed new insights into animal minds and positive social emotional experiences following their participa-tion in the program. Children’s responses also revealed the following themes as key aspects of their experience in the program: (1) new opportunities and interest in the program, (2) feeling more confident with horses and farm animals, (3) new social opportunities and support, and (4) sadness that the program was ending. These findings hold significance for human–animal interaction practitioners and educators interested in supporting children’s positive social and emotional experiences and stimulating children’s belief in animal mind and knowledge of and respect for the needs of diverse animals

Aging Phenotypes of Common Marmosets (Callithrix Jacchus)

Characterizing the phenotypic changes associated with aging in a short-lived primate is necessary in order to develop better translational models for human health, aging, and disease research. A population of conventionally housed marmoset monkeys was assessed to determine if phenotypes of body composition, hematology, and morphometrical measures were associated with age or risk of death. We found that the cause of mortality in older marmosets was more likely to be due to cardiac and chronic kidney disease than in younger marmosets. Older marmosets have decreased fat mass, morphometric measures, and serum albumin. Older marmosets are more likely to show a modified posture while at rest and this modified posture was significantly associated with an increased risk of imminent death. These assessments provide an initial definition of aged health in marmosets and a base for future translational aging research with this species

Strain and correlation of self-organized Ge_(1-x)Mn_x nanocolumns embedded in Ge (001)

We report on the structural properties of Ge_(1-x)Mn_x layers grown by molecular beam epitaxy. In these layers, nanocolumns with a high Mn content are embedded in an almost-pure Ge matrix. We have used grazing-incidence X-ray scattering, atomic force and transmission electron microscopy to study the structural properties of the columns. We demonstrate how the elastic deformation of the matrix (as calculated using atomistic simulations) around the columns, as well as the average inter-column distance can account for the shape of the diffusion around Bragg peaks.Comment: 9 pages, 7 figure

Interactional Structure Applied to the Identification and Generation of Visual Interactive Behavior: Robots that (Usually) Follow the Rules

Peer reviewe