Long-Range Navigation on Complex Networks using L\'evy Random Walks

We introduce a strategy of navigation in undirected networks, including regular, random, and complex networks, that is inspired by L\'evy random walks, generalizing previous navigation rules. We obtained exact expressions for the stationary probability distribution, the occupation probability, the mean first passage time, and the average time to reach a node on the network. We found that the long-range navigation using the L\'evy random walk strategy, compared with the normal random walk strategy, is more efficient at reducing the time to cover the network. The dynamical effect of using the L\'evy walk strategy is to transform a large-world network into a small world. Our exact results provide a general framework that connects two important fields: L\'evy navigation strategies and dynamics on complex networks.Comment: 6 pages, 3 figure

Evolution of transport under cumulative damage in metro systems

One dominant aspect of cities is transport and massive passenger mobilization which remains a challenge with the increasing demand on the public as cities grow. In addition, public transport infrastructure suffers from traffic congestion and deterioration, reducing its efficiency. In this paper, we study the capacity of transport in 33 worldwide metro systems under the accumulation of damage. We explore the gradual reduction of functionality in these systems associated with damage that occurs stochastically. The global transport of each network is modeled as the diffusive movement of Markovian random walkers on networks considering the capacity of transport of each link, where these links are susceptible to damage. Monte Carlo simulations of this process in metro networks show the evolution of the functionality of the system under damage considering all the complexity in the transportation structure. This information allows us to compare and classify the effect of damage in metro systems. Our findings provide a general framework for the characterization of the capacity to maintain the transport under failure in different systems described by networks.Comment: 9 pages; 4 figure

Explaining Africa’s public consumption procyclicality : revisiting old evidence

This paper compiles a novel dataset of time-varying measures of government consumption cyclicality for a panel of 46 African economies between 1960 and 2014. Government consumption has, generally, been highly procyclical over time in this group of countries. However, sample averages hide serious heterogeneity across countries with the majority of them showing procyclical behavior despite some positive signs of graduation from the “procyclicality trap” in a few cases. By means of weighted least squares regressions, we find that more developed African economies tend to have a smaller degree of government consumption procyclicality. Countries with higher social fragmentation and those are more reliant on foreign aid inflows tend to have a more procyclical government consumption policy. Better governance promotes counter- cyclical fiscal policy whileincreased democracy dampens it. Finally, some fiscal rules are important in curbing the procyclical behavior of government consumption.info:eu-repo/semantics/publishedVersio

Snakebites mapping in municipalities of the Coffee Triangle Region in Colombia using Geographic Information Systems (GIS)

Objective: We sought to develop epidemiological maps using geographical information systems (GIS) for the incidence of reported venomous snakebites in the Coffee-Triangle region of Colombia, between 2007 and 2011. Methods: Surveillance cases data (2007-2011) were used to estimate annual incidence rates of snakebites (cases/100,000 pop) to develop the first maps in the 53 municipalities of this region (departments Caldas, Quindío, Risaralda). The GIS software used was Kosmo Desktop 3.0RC1®. Thirty thematic maps were developed according to municipalities and years. Results: A total of 617 cases were reported (56.08% from Caldas, 32.58% from Risaralda and 11.35% from Quindío), for a cumulated regional rate of 25. 25 cases/100,000 pop (35.43 for Caldas, 21.86 for Risaralda and 12.81% for Quindío). The highest cumulated rate was reported in the less developed and more rural municipality of one department (Pueblo Rico, Risaralda) with 265.64 cases/100,000 pop. Between 2007 and 2011, a considerable increase was seen in the rates. At Pueblo Rico, Risaralda, there was a change from 41.04 cases/100,000pop in 2007 up to 63.11 cases/100,000pop in 2011 (1.54 times higher). From Caldas, Samaná showed a high variation from 19.47 to 77.7 (3.99 times higher). Conclusions: Morbidity of snakebites is highly concentrated in one department (Caldas). Use of GIS-based epidemiological maps allows guiding decisions-taking for prevention and control of public health problems that still represents a significant issue in the region and the country, such as snakebites

Snakebites mapping in municipalities of the Coffee Triangle Region in Colombia using Geographic Information Systems (GIS)

Objective: We sought to develop epidemiological maps using geographical information systems (GIS) for the incidence of reported venomous snakebites in the Coffee-Triangle region of Colombia, between 2007 and 2011. Methods: Surveillance cases data (2007-2011) were used to estimate annual incidence rates of snakebites (cases/100,000 pop) to develop the first maps in the 53 municipalities of this region (departments Caldas, Quindío, Risaralda). The GIS software used was Kosmo Desktop 3.0RC1®. Thirty thematic maps were developed according to municipalities and years. Results: A total of 617 cases were reported (56.08% from Caldas, 32.58% from Risaralda and 11.35% from Quindío), for a cumulated regional rate of 25. 25 cases/100,000 pop (35.43 for Caldas, 21.86 for Risaralda and 12.81% for Quindío). The highest cumulated rate was reported in the less developed and more rural municipality of one department (Pueblo Rico, Risaralda) with 265.64 cases/100,000 pop. Between 2007 and 2011, a considerable increase was seen in the rates. At Pueblo Rico, Risaralda, there was a change from 41.04 cases/100,000pop in 2007 up to 63.11 cases/100,000pop in 2011 (1.54 times higher). From Caldas, Samaná showed a high variation from 19.47 to 77.7 (3.99 times higher). Conclusions: Morbidity of snakebites is highly concentrated in one department (Caldas). Use of GIS-based epidemiological maps allows guiding decisions-taking for prevention and control of public health problems that still represents a significant issue in the region and the country, such as snakebites

Protective role of chaperone-mediated autophagy against atherosclerosis

Significance Cardiovascular diseases remain the leading cause of death worldwide, with atherosclerosis being the most common source of clinical events. Metabolic changes with aging associate with concurrent increased risk of both type 2 diabetes and cardiovascular disease, with the former further raising the risk of the latter. The activity of a selective type of autophagy, chaperone-mediated autophagy (CMA), decreases with age or upon dietary excesses. Here we study whether reduced CMA activity increases risk of atherosclerosis in mouse models. We have identified that CMA is up-regulated early in response to proatherogenic challenges and demonstrate that reduced systemic CMA aggravates vascular pathology in these conditions. We also provide proof-of-concept support that CMA up-regulation is an effective intervention to reduce atherosclerosis severity and progression