Interprétation paléoécologique des dunes à la limite des arbres, secteur nord-est de la mer d’Hudson, Québec

Dans le secteur nord-est de la mer d'Hudson, soit à la limite de la toundra forestière et de la toundra, les datations au radiocarbone les plus anciennes obtenues dans les paléosols dunaires (3490 ans BP dans le secteur continental et 2660 ans BP dans le secteur côtier) font ressortir un délai de plusieurs millénaires entre la mise en place des dépôts et leur remaniement par le vent. Une comparaison avec les données de Desponts (1990) et de Filion (1984) pour la forêt boréale montre que ce décalage est beaucoup plus considérable à la limite des forêts que dans le Haut-Boréal. Elle fait aussi ressortir une diminution, du sud vers le nord, du nombre de paléosols dans les séquences sédimentaires de dunes. Les chronologies éoliennes établies en toundra forestière indiquent une nette recrudescence après 2000 ans BP. Dans la toundra, cette augmentation ressort moins nettement de la chronologie, laquelle repose sur une majorité d'horizons organiques non carbonisés. La faible proportion d'horizons carbonisés dans les paléosols dunaires de la toundra indique que les feux ne constituent pas une condition nécessaire à la formation des dunes, alors qu'en toundra forestière, les séries continues d'horizons avec charbons de bois témoignent de l'importance du rôle des feux dans les récurrences éoliennes. L'analyse macrofossile des paléosols dunaires n'a pas permis d'identifier de périodes d'expansion de la limite des arbres.At the intersection of the forest tundra and the shrub tundra in the north-east sector of Hudson Bay, the oldest radiocarbon dates obtained from dune paleosols (3490 BP inland and 2660 BP on the coast), indicate an extended period (several millenia) between the time of sediment deposition and initiation of eolian activity. A comparison with the northern boreal forest data of Desponts (1991) and Filion (1984), indicated that this difference was far more accentuated at the tree-line than in the northern boreal forest. A decrease in the number of paleosols, from the south to the north, in the dune sequences was also demonstrated. The eolian record established for the forest tundra showed a sharp increase in eolian activity after 2000 BP. In the shrub tundra this increase is less clearly illustrated in the record, which was derived from a high proportion of non-charred organic material. The low count of charcoal samples in dune paleosols suggests that fire was not a critical factor in dune development, while in the forest tundra a continuous series of charcoal fragments was a direct response to fire-mediated eolian processes. Macrofossil analysis of dune paleosols did not allow identification of northward displacement of the tree-line.Im nordôstlichen Bereich der Hudson-See, d.h. an der Grenze von Waldtundra und Tundra, weisen die àltesten, in den Dùnen-Palâobôden gewonnenen Radiokarbondatierungen (3490 Jahre v.u.Z. im kontinentalen Gebiet und 2660 Jahre v.u.Z. im Kiistengebiet) einen Aufschub von mehreren tausend Jahren zwischen den Sedimentablagerungen und ihrer Verànderung durch den Wind auf. Ein Vergleich zwischen den Daten von Desponts (1990) und von Filion (1984) fur den nôrdlichen Waldgùrtel zeigt, dafS dieser Zeitunterschied an der Baumgrenze sehr viel beachtlicher ist als im hohen nôrlichen Waldgùrtel. Er IaBt auch eine Abnahme der Zahl der Palàobôden in den Diinen-Sedimentsequenzen von Suden nach Norden erkennen. Die fur die Waldtundra erstellten Windchronologien zeigen eine klare Zunahme nach 2000 Jahren v.u.Z. In der Tundra ist diese Zunahme weniger klar aus der Chronologie, welche auf einer Mehrheit nicht verkohlter organischer Horizonte beruht, zu erkennen. Der schwache Anteil verkohlter Horizonte in den Dùnen-Palàobôden zeigt, daB die Brànde keine notwendige Bedingung fur die Bildung der Dunen sind, wogegen in der Waldtundra die durchgàngigen Horizonte mit Holzkohle die wichtige RoIIe der Brànde bei den Windprozessen bezeugen. Die makrofossile Analyse der Dûnen-Palàobôden hat nicht erlaubt, die Perioden der Ausdehnung der Baumgrenze zu identifizieren

Uncovering changes in proteomic signature of rat pelvic floor muscles in pregnancy.

BackgroundStructural and functional changes of the rat pelvic floor muscles during pregnancy, specifically, sarcomerogenesis, increase in extracellular matrix content, and higher passive tension at larger strains protect the integral muscle components against birth injury. The mechanisms underlying these antepartum alterations are unknown. Quantitative proteomics is an unbiased method of identifying protein expression changes in differentially conditioned samples. Therefore, proteomics analysis provides an opportunity to identify molecular mechanisms underlying antepartum muscle plasticity.ObjectiveTo elucidate putative mechanisms accountable for pregnancy-induced adaptations of the pelvic floor muscles, and to identify other novel antepartum alterations of the pelvic floor muscles.Materials and methodsPelvic floor muscles, comprised of coccygeus, iliocaudalis, and pubocaudalis, and nonpelvic limb muscle, tibialis anterior, were harvested from 3-month-old nonpregnant and late-pregnant Sprague-Dawley rats. After tissue homogenization, trypsin-digested peptides were analyzed by ultra-high-performance liquid chromatography coupled with tandem mass spectroscopy using nano-spray ionization. Peptide identification and label free relative quantification analysis were carried out using Peaks Studio 8.5 software (Bioinformatics Solutions Inc., Waterloo, ON, Canada). Proteomics data were visualized using the Qlucore Omics Explorer (New York, NY). Differentially expressed peptides were identified using the multi-group differential expression function, with q-value cutoff set at <0.05. Proteomic signatures of the pelvic floor muscles were compared to nonpelvic limb muscle and between nonpregnant and pregnant states.ResultsUnsupervised clustering of the data showed clear separation between samples from nonpregnant and pregnant animals along principal component 1 and between pelvic and nonpelvic muscles along principal component 2. Four major gene clusters were identified segregating proteomic signatures of muscles examined in nonpregnant vs pregnant states: (1) proteins increased in the pelvic floor muscles only; (2) proteins increased in the pelvic floor muscles and tibialis anterior; (3) proteins decreased in the pelvic floor muscles and tibialis anterior; and (4) proteins decreased in the pelvic floor muscles alone. Cluster 1 included proteins involved in cell cycle progression and differentiation. Cluster 2 contained proteins that participate in mitochondrial metabolism. Cluster 3 included proteins involved in transcription, signal transduction, and phosphorylation. Cluster 4 comprised proteins involved in calcium-mediated regulation of muscle contraction via the troponin tropomyosin complex.ConclusionPelvic floor muscles gain a distinct proteomic signature in pregnancy, which provides a mechanistic foundation for the antepartum physiological alterations acquired by these muscles. Variability in genes encoding these proteins may alter plasticity of the pelvic floor muscles and therefore the extent of the protective pregnancy-induced adaptations. Furthermore, pelvic floor muscles' proteome is divergent from that of the nonpelvic skeletal muscles

Questions et perspectives de recherche concernant la pauvreté chez les jeunes

Le nombre de jeunes pauvres, âgés de 16 à 24 ans, qui vivent seuls de façon provisoire ou durable, est en progression rapide au Québec. Cette période de la vie est traversée aujourd'hui par de multiples paradoxes allant d'un désir d'autonomie précoce, fondé sur des valeurs modernes d'affirmation de soi et de liberté, à l'allongement de la dépendance, surtout économique, dans un contexte social en mutation. Si les statistiques renseignent sur les caractéristiques de la pauvreté, telles qu'établies à partir des seuils de faible revenu, elles ne permettent toutefois pas de saisir la complexité des situations, des représentations et des stratégies correspondantes. Le rappel de ces données sera suivi de quelques pistes de réflexion qui pourront alimenter éventuellement la recherche et l'action.In Quebec, the number of poor youths, aged 16 to 24, living alone on a temporary or indefinite basis is quickly expanding. This phase of life is nowadays characterized by many a paradox. The range stretches from a nearly quest for autonomy, brought about by modern values such as self-assertion and independence, to prolonged dependency, mainly financial. If statistical data pertaining to poverty are readily available, they do not however display the many faces taken on by poverty as well as the various representations and strategies associated. The underscoring of this confrontation gives way to the examination of different approaches for the study and the eventual circumventing of juvenile poverty

Comparison of reproducibility, accuracy, sensitivity, and specificity of miRNA quantification platforms

Given the increasing interest in their use as disease biomarkers, the establishment of reproducible, accurate, sensitive, and specific platforms for microRNA (miRNA) quantification in biofluids is of high priority. We compare four platforms for these characteristics: small RNA sequencing (RNA-seq), FirePlex, EdgeSeq, and nCounter. For a pool of synthetic miRNAs, coefficients of variation for technical replicates are lower for EdgeSeq (6.9%) and RNA-seq (8.2%) than for FirePlex (22.4%); nCounter replicates are not performed. Receiver operating characteristic analysis for distinguishing present versus absent miRNAs shows small RNA-seq (area under curve 0.99) is superior to EdgeSeq (0.97), nCounter (0.94), and FirePlex (0.81). Expected differences in expression of placenta-associated miRNAs in plasma from pregnant and non-pregnant women are observed with RNA-seq and EdgeSeq, but not FirePlex or nCounter. These results indicate that differences in performance among miRNA profiling platforms impact ability to detect biological differences among samples and thus their relative utility for research and clinical use

The effect of the eHealth intervention ‘MyPlan 1.0’ on physical activity in adults who visit general practice : a quasi-experimental trial

Physical inactivity is one of the major risk factors for poor health in the world. Therefore, effective interventions that promote physical activity are needed. Hence, we developed an eHealth intervention for adults, i.e., ‘MyPlan 1.0’, which includes self-regulation techniques for behaviour change. This study examined the effect of ‘MyPlan 1.0’ on physical activity (PA) levels in general practice. 615 adults (≥18 years) were recruited in 19 Flemish general practices, for the intervention group (n = 328) or for the wait-list control group (n = 183). Participants in the intervention group received the web-based intervention ‘MyPlan 1.0’ and were prompted to discuss their personal advice/action plan with their general practitioner. Participants in the wait-list control group only received general advice from the website. Self-reported physical activity was assessed with the International Physical Activity Questionnaire (IPAQ) at baseline and after one month. A three-level (general practice, adults, time) regression analysis was conducted in MLwiN. Significant intervention effects were found for total PA and moderate to vigorous PA with an increase for the intervention group compared to a decrease in the control condition. However, there was a high dropout rate in the intervention group (76%) and the wait-list control group (57%). Our self-regulation intervention was effective in increasing physical activity levels in adults. Future studies should consider strategies to prevent the large dropout from participants

The accuracy of smart devices for measuring physical activity in daily life : validation study

Background: Wearables for monitoring physical activity (PA) are increasingly popular. These devices are not only used by consumers to monitor their own levels of PA but also by researchers to track the behavior of large samples. Consequently, it is important to explore how accurately PA can be tracked via these devices. Objectives: The aim of this study was, therefore, to investigate convergent validity of 3 Android Wear smartwatches-Polar M600 (Polar Electro Oy, Kempele, Finland), Huawei Watch (Huawei Technologies Co, Ltd, Shenzhen, Guangdong, China), Asus Zenwatch3 (AsusTek Computer Inc, Taipei, Taiwan)-and Fitbit Charge with an ActiGraph accelerometer for measuring steps and moderate to vigorous physical activity (MVPA) on both a day level and 15-min level. Methods: A free-living protocol was used in which 36 adults engaged in usual daily activities over 2 days while wearing 2 different wearables on the nondominant wrist and an ActiGraph GT3X+ accelerometer on the hip. Validity was evaluated on both levels by comparing each wearable with the ActiGraph GT3X+ accelerometer using correlations and Bland-Altman plots in IBM SPSS 24.0. Results: On a day level, all devices showed strong correlations (Spearman r=.757-.892) and good agreement (interclass correlation coefficient, ICC=.695-.885) for measuring steps, whereas moderate correlations (Spearman r=.557-.577) and low agreement (ICC=.377-.660) for measuring MVPA. Bland-Altman revealed a systematic overestimation of the wearables for measuring steps but a variation between over-and undercounting of MVPA. On a 15-min level, all devices showed strong correlations (Spearman r=.752-.917) and good agreement (ICC=.792-.887) for measuring steps, whereas weak correlations (Spearman r=.116-.208) and low agreement (ICC=.461-.577) for measuring MVPA. Bland-Altman revealed a systematic overestimation of the wearables for steps but under- or overestimation for MVPA depending on the device. Conclusions: In sum, all 4 consumer-level devices can be considered accurate step counters in free-living conditions. This study, however, provides evidence of systematic bias for all devices in measurement of MVPA. The results on a 15-min level also indicate that these devices are not sufficiently accurate to provide correct real-time feedback

Creating successful valuing nature initiatives: A guide to analysing local context and developing strong theories of change

The guide aims to help practitioners understand local context and external pressures – the formal and informal institutional, political, legal, economic and social setting of conservation – to guide action for better ecosystem management

Nonsense-Mediated RNA Decay Influences Human Embryonic Stem Cell Fate.

Nonsense-mediated RNA decay (NMD) is a highly conserved pathway that selectively degrades specific subsets of RNA transcripts. Here, we provide evidence that NMD regulates early human developmental cell fate. We found that NMD factors tend to be expressed at higher levels in human pluripotent cells than in differentiated cells, raising the possibility that NMD must be downregulated to permit differentiation. Loss- and gain-of-function experiments in human embryonic stem cells (hESCs) demonstrated that, indeed, NMD downregulation is essential for efficient generation of definitive endoderm. RNA-seq analysis identified NMD target transcripts induced when NMD is suppressed in hESCs, including many encoding signaling components. This led us to test the role of TGF-β and BMP signaling, which we found NMD acts through to influence definitive endoderm versus mesoderm fate. Our results suggest that selective RNA decay is critical for specifying the developmental fate of specific human embryonic cell lineages

A self-regulation-based eHealth and mHealth intervention for an active lifestyle in adults with type 2 diabetes : protocol for a randomized controlled trial

Background: Adoption of an active lifestyle plays an important role in the management of type 2 diabetes. Online interventions targeting lifestyle changes in adults with type 2 diabetes have provided mixed results. Previous research highlights the importance of creating theory-based interventions adapted to the population's specific needs. The online intervention "MyPlan 2.0" targets physical activity and sedentary behavior in adults with type 2 diabetes. This intervention is grounded in the self-regulation framework and, by incorporating the feedback of users with type 2 diabetes, iteratively adapted to its target population. Objective: The aim of this paper is to thoroughly describe "MyPlan 2.0" and the study protocol that will be used to test the effectiveness of this intervention to alter patients' levels of physical activity and sedentary behavior. Methods: A two-arm superiority randomized controlled trial will be performed. Physical activity and sedentary behavior will be measured using accelerometers and questionnaires. Furthermore, using questionnaires and diaries, patients' stressors and personal determinants for change will be explored in depth. To evaluate the primary outcomes of the intervention, multilevel analyses will be conducted. Results: The randomized controlled trial started in January 2018. As participants can start at different moments, we aim to finish all testing by July 2019. Conclusions: This study will increase our understanding about whether and how a theory-based online intervention can help adults with type 2 diabetes increase their level of physical activity and decrease their sedentary time