Оценка надежности высоконадежных систем с учетом ЗИП

Предложены приближенные верхние и нижние оценки коэффициента готовности высоконадежной восстанавливаемой системы со структурной избыточностью. Полученные расчетные соотношения могут использоваться для оценки надежности высоконадежных систем с учетом различных стратегий пополнения ЗИП

Order-of-magnitude speedup for steady states and traveling waves via Stokes preconditioning in Channelflow and Openpipeflow

Steady states and traveling waves play a fundamental role in understanding hydrodynamic problems. Even when unstable, these states provide the bifurcation-theoretic explanation for the origin of the observed states. In turbulent wall-bounded shear flows, these states have been hypothesized to be saddle points organizing the trajectories within a chaotic attractor. These states must be computed with Newton's method or one of its generalizations, since time-integration cannot converge to unstable equilibria. The bottleneck is the solution of linear systems involving the Jacobian of the Navier-Stokes or Boussinesq equations. Originally such computations were carried out by constructing and directly inverting the Jacobian, but this is unfeasible for the matrices arising from three-dimensional hydrodynamic configurations in large domains. A popular method is to seek states that are invariant under numerical time integration. Surprisingly, equilibria may also be found by seeking flows that are invariant under a single very large Backwards-Euler Forwards-Euler timestep. We show that this method, called Stokes preconditioning, is 10 to 50 times faster at computing steady states in plane Couette flow and traveling waves in pipe flow. Moreover, it can be carried out using Channelflow (by Gibson) and Openpipeflow (by Willis) without any changes to these popular spectral codes. We explain the convergence rate as a function of the integration period and Reynolds number by computing the full spectra of the operators corresponding to the Jacobians of both methods.Comment: in Computational Modelling of Bifurcations and Instabilities in Fluid Dynamics, ed. Alexander Gelfgat (Springer, 2018

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Lifestyle Change, Nutrition Transition and Cardiovascular Risk in Settat Region, Morocco

Ibtissam Talha, Noureddine Elkhoudri, Abderraouf Hilali Laboratory of Health Sciences and Technologies, Higher Institute of Health Sciences, Hassan First University of Settat, Settat, MoroccoCorrespondence: Ibtissam Talha, Email [email protected]: Morocco, a north African country undergoing a significant nutritional transition, with a clear shift from traditional dietary patterns towards those of the Western model. This transition has a profound impact on the health of its population, most notably in the rise of chronic illnesses and mainly cardiovascular diseases. The following cross-sectional study examines risk factors associated with these nutritional and lifestyle changes and their effects on cardiovascular risk among adults residing in Settat, central Morocco.Subjects and Methods: The study was conducted between January 20th and April 25th, 2023, involving 981 participants aged 20 and above who attended health centers in Settat. Risk factors were assessed using a questionnaire encompassing sociodemographic, health, clinical, dietary, and lifestyle data. To estimate cardiovascular risk, the National Health and Nutrition Examination Survey “NHANES” risk score was employed.Results: Abdominal obesity, a sedentary lifestyle, hypertension, hyperglycemia, and hypercholesterolemia stood out as the most prevalent risk factors, with percentages of 44.3%, 69.7%, 17.6%, 15%, and 26.5%, respectively. As per the “NHANES” risk score, 22.8% were projected to face a cardiovascular risk exceeding 20% within the following five years. This risk was notably linked to the population’s sedentary lifestyle and the dietary habits oscillating between the traditional Moroccan pattern and the Western one, marking the nutritional transition.Conclusion: The high prevalence of cardiovascular risk factors underlines the substantial impact of lifestyle changes and nutritional transitions on cardiovascular risk. Consequently, this situation calls for immediate action to devise and deploy strategies aimed at promoting healthy lifestyle choices. Raising awareness about the critical importance of maintaining such a lifestyle is imperative to mitigate the risks and prevent the onset of cardiovascular diseases.Keywords: Nutritional transition, lifestyle change, cardiovascular incidence, cardiovascular risk, settat, Morocc

Evolution de la mortalité infantile et juvénile dans deux milieux défavorisés : la zone péri-urbaine El Azzouzia et la vallée Erdouze du Haut Atlas (Marrakech, Maroc)

Les populations vulnérables sont les plus exposées aux maladies et au manque d'hygiène. Vivant dans des conditions précaires, elles connaissent des taux de mortalité infantile et juvénile très élevés. Dans le présent article, nous comparons l'évolution des quotients de mortalité infantile, juvénile et infanto-juvénile dans le temps et dans l'espace. Les zones étudiées sont marginalisées et défavorisées à savoir la zone péri-urbaine de la ville de Marrakech (El Azzouzia : 1984-2000) et une des vallées du Haut Atlas occidental de Marrakech (vallée d'Erdouze : 1985-1997). L'évolution de la mortalité infantile est également analysée en fonction du sexe et en fonction de la vaccination. Dans les deux zones les quotients de mortalité sont très élevés par rapport à la moyenne nationale. Comparée dans le temps, la mortalité a chuté dans les deux zones, mais reste plus importante dans la vallée que dans la zone péri-urbaine. La chute de cette mortalité est plus spectaculaire avec la vaccination. La mortalité infantile diminue de plus de la moitié chez les vaccinés que ce soit dans le temps ou dans l'espac