90 research outputs found
Arctic Security and Defence in a Competitive World
On November 22, 2021, Dr. Andrea Charron, Director for the Center for Defence and Security Studies at the University of Manitoba, presented on Arctic Security and Defence in a Competitive World at the 2021 CASIS West Coast Security Conference. The primary focus of Dr. Charronâs presentation was on three key areas of questioning the competitiveness of international order within Arctic security and defence. These areas were: competition, decision makers, and fora for navigating competition. The presentation was followed by a question and answer period with questions from the audience and CASIS Vancouver executives
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Examining the predictability of the Stratospheric Sudden Warming of January 2013 using multiple NWP systems
The first multi-model study to estimate the predictability of a boreal Sudden Stratospheric Warming (SSW) is performed using five NWP systems. During the 2012-2013 boreal winter, anomalous upward propagating planetary wave activity was observed towards the end of December, which followed by a rapid deceleration of the westerly circulation around 2 January 2013, and on 7 January 2013 the zonal mean zonal wind at 60°N and 10 hPa reversed to easterly. This stratospheric dynamical activity was followed by an equatorward shift of the tropospheric jet stream and by a high pressure anomaly over the North Atlantic, which resulted in severe cold conditions in the UK and Northern Europe. In most of the five models, the SSW event was predicted 10 days in advance. However, only some ensemble members in most of the models predicted weakening of westerly wind when the models were initialized 15 days in advance of the SSW. Further dynamical analysis of the SSW shows that this event was characterized by the anomalous planetary wave-1 amplification followed by the anomalous wave-2 amplification in the stratosphere, which resulted in a split vortex occurring between 6 January 2013 and 8 January 2013. The models have some success in reproducing wave-1 activity when initialized 15 days in advance, they but generally failed to produce the wave-2 activity during the final days of the event. Detailed analysis shows that models have reasonably good skill in forecasting tropospheric blocking features that stimulate wave-2 amplification in the troposphere, but they have limited skill in reproducing wave-2 amplification in the stratosphere
Navigating protein landscapes with a machine-learned transferable coarse-grained model
The most popular and universally predictive protein simulation models employ
all-atom molecular dynamics (MD), but they come at extreme computational cost.
The development of a universal, computationally efficient coarse-grained (CG)
model with similar prediction performance has been a long-standing challenge.
By combining recent deep learning methods with a large and diverse training set
of all-atom protein simulations, we here develop a bottom-up CG force field
with chemical transferability, which can be used for extrapolative molecular
dynamics on new sequences not used during model parametrization. We demonstrate
that the model successfully predicts folded structures, intermediates,
metastable folded and unfolded basins, and the fluctuations of intrinsically
disordered proteins while it is several orders of magnitude faster than an
all-atom model. This showcases the feasibility of a universal and
computationally efficient machine-learned CG model for proteins
Why East Germany Did Not Become a New Mezzogiorno
Economic integration is generally thought to favour convergence in the economic performance of previously separated regions; but this is far from universally true, as the experience of the members of the Eurozone testifies. The paper considers the two sharply contrasting cases of East and West German convergence following reunification and the enduring poverty of the Italian Mezzogiorno since Italian unification a century and a half ago. In both countries, political integration delivers much higher consumption in the lagging relative to the leading region than of per capita GDP. Consumption convergence can be supported by transfers but âproductionâ convergence ultimately requires catch-up in the production of tradeables. The paper demonstrates the radically different performance of the tradeable sector in the two cases, and suggests that this may be the result of differences in labour market flexibility, in investment performance and in the social norms required for the production of complex manufacturing
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Review: the predictability of the extra-tropical stratosphere on monthly timescales and its impact on the skill of tropospheric forecasts
Extreme variability of the winter- and spring-time stratospheric polar vortex has been shown to affect
extratropical tropospheric weather. Therefore, reducing stratospheric forecast error may be one way to improve
the skill of tropospheric weather forecasts. In this review, the basis for this idea is examined. A range of studies of different stratospheric extreme vortex events shows that they can be skilfully forecasted beyond five days and into the sub-seasonal range (0-30 days) in some cases. Separate studies show that typical errors in forecasting a stratospheric extreme vortex event can alter tropospheric forecasts skill by 5-7% in the extratropics on sub-seasonal timescales. Thus understanding what limits stratospheric predictability is of significant interest to
operational forecasting centres. Both limitations in forecasting tropospheric planetary waves and stratospheric
model biases have been shown to be important in this context
ccdc80-l1 Is Involved in Axon Pathfinding of Zebrafish Motoneurons
Axon pathfinding is a subfield of neural development by which neurons send out axons to reach the correct targets. In particular, motoneurons extend their axons toward skeletal muscles, leading to spontaneous motor activity. In this study, we identified the zebrafish Ccdc80 and Ccdc80-like1 (Ccdc80-l1) proteins in silico on the basis of their high aminoacidic sequence identity with the human CCDC80 (Coiled-Coil Domain Containing 80). We focused on ccdc80-l1 gene that is expressed in nervous and non-nervous tissues, in particular in territories correlated with axonal migration, such as adaxial cells and muscle pioneers. Loss of ccdc80-l1 in zebrafish embryos induced motility issues, although somitogenesis and myogenesis were not impaired. Our results strongly suggest that ccdc80-l1 is involved in axon guidance of primary and secondary motoneurons populations, but not in their proper formation. ccdc80-l1 has a differential role as regards the development of ventral and dorsal motoneurons, and this is consistent with the asymmetric distribution of the transcript. The axonal migration defects observed in ccdc80-l1 loss-of-function embryos are similar to the phenotype of several mutants with altered Hedgehog activity. Indeed, we reported that ccdc80-l1 expression is positively regulated by the Hedgehog pathway in adaxial cells and muscle pioneers. These findings strongly indicate ccdc80-l1 as a down-stream effector of the Hedgehog pathway
Local and regional components of aerosol in a heavily trafficked street canyon in central London derived from PMF and cluster analysis of single-particle ATOFMS spectra.
Positive matrix factorization (PMF) has been applied to single particle ATOFMS spectra collected on a six lane heavily trafficked road in central London (Marylebone Road), which well represents an urban street canyon. PMF analysis successfully extracted 11 factors from mass spectra of about 700,000 particles as a complement to information on particle types (from K-means cluster analysis). The factors were associated with specific sources and represent the contribution of different traffic related components (i.e., lubricating oils, fresh elemental carbon, organonitrogen and aromatic compounds), secondary aerosol locally produced (i.e., nitrate, oxidized organic aerosol and oxidized organonitrogen compounds), urban background together with regional transport (aged elemental carbon and ammonium) and fresh sea spray. An important result from this study is the evidence that rapid chemical processes occur in the street canyon with production of secondary particles from road traffic emissions. These locally generated particles, together with aging processes, dramatically affected aerosol composition producing internally mixed particles. These processes may become important with stagnant air conditions and in countries where gasoline vehicles are predominant and need to be considered when quantifying the impact of traffic emissions.This is the author accepted manuscript. The final version is available via ACS at http://pubs.acs.org/doi/abs/10.1021/es506249z
Systems medicine and integrated care to combat chronic noncommunicable diseases
We propose an innovative, integrated, cost-effective health system to combat major non-communicable diseases (NCDs), including cardiovascular, chronic respiratory, metabolic, rheumatologic and neurologic disorders and cancers, which together are the predominant health problem of the 21st century. This proposed holistic strategy involves comprehensive patient-centered integrated care and multi-scale, multi-modal and multi-level systems approaches to tackle NCDs as a common group of diseases. Rather than studying each disease individually, it will take into account their intertwined gene-environment, socio-economic interactions and co-morbidities that lead to individual-specific complex phenotypes. It will implement a road map for predictive, preventive, personalized and participatory (P4) medicine based on a robust and extensive knowledge management infrastructure that contains individual patient information. It will be supported by strategic partnerships involving all stakeholders, including general practitioners associated with patient-centered care. This systems medicine strategy, which will take a holistic approach to disease, is designed to allow the results to be used globally, taking into account the needs and specificities of local economies and health systems
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