61 research outputs found
Stochastic and Discrete Time Models of Long-Range Turbulent Transport in the Scrape-Off Layer
Two dimensional stochastic time model of scrape-off layer (SOL) turbulent
transport is studied. Instability arisen in the system with respect to the
stochastic perturbations of both either density or vorticity reveals itself in
the strong outward bursts of particle density propagating ballistically across
the SOL. The stability and possible stabilization of the cross- field turbulent
system depend very much upon the reciprocal correlation time between density
and vorticity fluctuations. Pdf of the particle flux for the large magnitudes
of flux events can be modelled with a simple discrete time toy model of random
walks concluding at a boundary. The spectra of wandering times feature the pdf
of particle flux in the model and qualitatively reproduce the experimental
statistics of transport events.Comment: 21 pages,11 figure
Homogeneous and Scalable Gene Expression Regulatory Networks with Random Layouts of Switching Parameters
We consider a model of large regulatory gene expression networks where the
thresholds activating the sigmoidal interactions between genes and the signs of
these interactions are shuffled randomly. Such an approach allows for a
qualitative understanding of network dynamics in a lack of empirical data
concerning the large genomes of living organisms. Local dynamics of network
nodes exhibits the multistationarity and oscillations and depends crucially
upon the global topology of a "maximal" graph (comprising of all possible
interactions between genes in the network). The long time behavior observed in
the network defined on the homogeneous "maximal" graphs is featured by the
fraction of positive interactions () allowed between genes.
There exists a critical value such that if , the
oscillations persist in the system, otherwise, when it tends to
a fixed point (which position in the phase space is determined by the initial
conditions and the certain layout of switching parameters). In networks defined
on the inhomogeneous directed graphs depleted in cycles, no oscillations arise
in the system even if the negative interactions in between genes present
therein in abundance (). For such networks, the bidirectional edges
(if occur) influence on the dynamics essentially. In particular, if a number of
edges in the "maximal" graph is bidirectional, oscillations can arise and
persist in the system at any low rate of negative interactions between genes
(). Local dynamics observed in the inhomogeneous scalable regulatory
networks is less sensitive to the choice of initial conditions. The scale free
networks demonstrate their high error tolerance.Comment: LaTeX, 30 pages, 20 picture
A Phase Transistion in the Water Coupled to a Local External Perturbation
A flux of ideal fluid coupled to perturbation is investigated by
nonperturbative methods of the quantum field theory. Asymptotic behavior of the
flux coupled to perturbation turns out to be similiar to that of superfluids.Comment: 17 pages, 5 figures, Late
Nonlinear Diffusion Through Large Complex Networks Containing Regular Subgraphs
Transport through generalized trees is considered. Trees contain the simple
nodes and supernodes, either well-structured regular subgraphs or those with
many triangles. We observe a superdiffusion for the highly connected nodes
while it is Brownian for the rest of the nodes. Transport within a supernode is
affected by the finite size effects vanishing as For the even
dimensions of space, , the finite size effects break down the
perturbation theory at small scales and can be regularized by using the
heat-kernel expansion.Comment: 21 pages, 2 figures include
Tuberculosis
Asserts that despite progress in controlling tuberculosis (TB), the decline in incidence has been disappointing, pointing to the need for new strategies and more effective tools. HIV/AIDS is one factor that challenges effective control of TB, especially in Southern African countries. Three key elements are needed to achieve effective TB control and to meet the Sustainable Development Goals: (1) early and accurate diagnosis and drug-sensitivity testing, (2) patient access to and completion of effective treatment, and (3) prevention of progression from latent infection to disease. Prevention requires vaccination and screening of individual at high risk as well as interventions such as air disinfection and the use of masks and respirators in hospitals and other congregate settings. Recommendations stress the need to strengthen health systems in high-burden countries by emphasizing community-based care over hospital care; to improve information systems to ensure patient adherence and manage medication supply chains; and to invest in research to develop the necessary interventions. Fundamentally, current global TB control strategies must undergo revision and receive significant research funding
MDR/XDR-TB management of patients and contacts: Challenges facing the new decade. The 2020 clinical update by the Global Tuberculosis Network.
The continuous flow of new research articles on MDR-TB diagnosis, treatment, prevention and rehabilitation requires frequent update of existing guidelines. This review is aimed at providing clinicians and public health staff with an updated and easy-to-consult document arising from consensus of Global Tuberculosis Network (GTN) experts. The core published documents and guidelines have been reviewed, including the recently published MDR-TB WHO rapid advice and ATS/CDC/ERS/IDSA guidelines. After a rapid review of epidemiology and risk factors, the clinical priorities on MDR-TB diagnosis (including whole genome sequencing and drug-susceptibility testing interpretations) and treatment (treatment design and management, TB in children) are discussed. Furthermore, the review comprehensively describes the latest information on contact tracing and LTBI management in MDR-TB contacts, while providing guidance on post-treatment functional evaluation and rehabilitation of TB sequelae, infection control and other public health priorities
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