Griffiths phases and localization in hierarchical modular networks

We study variants of hierarchical modular network models suggested by Kaiser and Hilgetag [Frontiers in Neuroinformatics, 4 (2010) 8] to model functional brain connectivity, using extensive simulations and quenched mean-field theory (QMF), focusing on structures with a connection probability that decays exponentially with the level index. Such networks can be embedded in two-dimensional Euclidean space. We explore the dynamic behavior of the contact process (CP) and threshold models on networks of this kind, including hierarchical trees. While in the small-world networks originally proposed to model brain connectivity, the topological heterogeneities are not strong enough to induce deviations from mean-field behavior, we show that a Griffiths phase can emerge under reduced connection probabilities, approaching the percolation threshold. In this case the topological dimension of the networks is finite, and extended regions of bursty, power-law dynamics are observed. Localization in the steady state is also shown via QMF. We investigate the effects of link asymmetry and coupling disorder, and show that localization can occur even in small-world networks with high connectivity in case of link disorder.Comment: 18 pages, 20 figures, accepted version in Scientific Report

Analysing sporting goods manufacturers' environmental management tools

Organizations around the developed world are facing pressure from governments, international agreements, society and various stakeholders, to improve their behavior towards the natural environment. The application of environmental management tools may be an important step towards sustainability and the preservation of environmental values, however marketing could be the key – with the help of information and communication technologies (ICT) – in publicizing and spreading these ideas thus forming customers’, stakeholders’ attitude in this respect.The aim of this study was to define the concept of environmental consciousness and environmentally conscious behaviour, then to present the shift the traditional marketing philosophy towards the sustainable marketing approach, finally to analyse two top sporting goods manufacturers’ (Nike, Adidas) environmental management tools with the help of data gained from their web sites, reports, case studies. Interpreting environmental consciousness is difficult without knowing the attitude to it. In spite of that it is important to distinguish between environmental consciousness and environmentally conscious attitude, because consciousness often appears in attitude influenced by other, outer effects.The environmental conscious attitude of companies in itself is not enough for making use of the advantages deriving from a positive environmental concern. They need to pursue more active communication, to „green” the whole of marketing activities. Thus marketing seems a possible means to naturalize and expand environmental protection both among customers and in company practice. According to the analysed companies, we need to say, that they are commitment with the environmental protection. They are used state-of-theart technologies to make their activity greener and introduce these with full particulars, examples e.g. ColorDry technologies, Better Cotton, The Framaprene ECO heel. Either Nike, Inc., or Adidas Group realised that ICT have the ability to improve efficiency and cut the use of material goods, thus reducing energy demands and the burden upon the environment

On the robustness of the metric dimension of grid graphs to adding a single edge

The metric dimension (MD) of a graph is a combinatorial notion capturing the minimum number of landmark nodes needed to distinguish every pair of nodes in the graph based on graph distance. We study how much the MD can increase if we add a single edge to the graph. The extra edge can either be selected adversarially, in which case we are interested in the largest possible value that the MD can take, or uniformly at random, in which case we are interested in the distribution of the MD. The adversarial setting has already been studied by [Eroh et. al., 2015] for general graphs, who found an example where the MD doubles on adding a single edge. By constructing a different example, we show that this increase can be as large as exponential. However, we believe that such a large increase can occur only in specially constructed graphs, and that in most interesting graph families, the MD at most doubles on adding a single edge. We prove this for $d$-dimensional grid graphs, by showing that $2d$ appropriately chosen corners and the endpoints of the extra edge can distinguish every pair of nodes, no matter where the edge is added. For the special case of $d=2$, we show that it suffices to choose the four corners as landmarks. Finally, when the extra edge is sampled uniformly at random, we conjecture that the MD of 2-dimensional grids converges in probability to $3+\mathrm{Ber}(8/27)$, and we give an almost complete proof

Simulation of 1+1 dimensional surface growth and lattices gases using GPUs

Restricted solid on solid surface growth models can be mapped onto binary lattice gases. We show that efficient simulation algorithms can be realized on GPUs either by CUDA or by OpenCL programming. We consider a deposition/evaporation model following Kardar-Parisi-Zhang growth in 1+1 dimensions related to the Asymmetric Simple Exclusion Process and show that for sizes, that fit into the shared memory of GPUs one can achieve the maximum parallelization speedup ~ x100 for a Quadro FX 5800 graphics card with respect to a single CPU of 2.67 GHz). This permits us to study the effect of quenched columnar disorder, requiring extremely long simulation times. We compare the CUDA realization with an OpenCL implementation designed for processor clusters via MPI. A two-lane traffic model with randomized turning points is also realized and the dynamical behavior has been investigated.Comment: 20 pages 12 figures, 1 table, to appear in Comp. Phys. Com

Wearable Activity Trackers Usage among University Students

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Green tree retention enhances negative short-term effects of clear-cutting on enchytraeid assemblages in a temperate forest

We studied the response of enchytraeid (Annelida: Oligochaeta) community structure to different forest management treatments via an open-field forestry experiment in a managed sessile oak-hornbeam forest in Hungary. The applied forestry treatments were 1) clear-cutting 2) clear cutting with a small patch of retention tree group, 3) gap-cutting, 4) preparation cutting and 5) control (closed mature stand). Our questions were: how did the selected forestry treatments influence the abundance and species richness of enchytraeids two years after the intervention, and how could the worms compensate the altered environmental conditions by vertical movements in topsoil layers (0–12 cm). The effects of the treatments on the species composition of the assemblages and species-specific responses were also analysed. Two years after the treatments, a strong response of enchytraeids was observed in clear-cutting and even more in retention tree group: in both treatments the abundance and the species richness of enchytraeids were reduced. Species did not show vertical movements into deeper layers and were not able to tolerate the altered soil conditions caused by changed microclimate. Gap-cutting and preparation cutting did not differ significantly from control plots. Our study showed that right after the interventions tree retention at the size of one tree height in diameter had no sheltering effect on this important soil decomposer animal community. These results are in contrast with earlier findings in boreal zones, where soil organic layer is considered a well buffered habitat against environmental changes. Oppositely, enchytraeid assemblages in a temperate deciduous forest are more diverse but seem more vulnerable to management-related alterations in soil conditions (soil temperate increment, reduced soil moisture)

Nike vs Adidas – Környezetvédelmi erőfeszítések eredményei = Nike vs Adidas – Results of Environmental Efforts

A „felelős magatartás” kérdéskörével foglalkozó kutatások alapján elmondható, hogy a fogalom tisztázása nem egyszerű feladat, hiszen a szakirodalom sem egységes. Az eltérő meghatározások hasonlóak abban a tekintetben, hogy az üzletmenetben meg kell teremtődnie egy egészséges és fenntartható egyensúlynak a gazdasági érdekek, a társadalmi elvárások és a környezeti értékek figyelembe vétele között. A felelős magatartás megjelenése a gazdasági élet különböző szektoraiban, eltérő tevékenységek révén valósulhat meg. Az egyik ilyen, napjainkban egyre népszerűbb kutatási terület, a sportszektor felelős magatartásának vizsgálata. Vitathatatlan, hogy minden sporttal kapcsolatos tevékenység hatással van a természetes környezetre, hiszen természeti erőforrásokat használ. A területek kisajátítása, a biodiverzitásra gyakorolt hatás, az ivóvíz minőségű vizek felhasználása, a hulladék kibocsátása, a vendéglátás, a sportlétesítmények építése és működtetés, valamint a sporteszközök gyártása és eladása megsokszorozza azokat a megoldásra, zöldítésre váró feladatokat, melyeken segíthet a felelős magatartás. Jelen tanulmány célja, hogy vezető piaci pozícióban lévő multinacionális sportszer- és sportruházat gyártó vállalatok – Nike, Adidas – tevékenységébe integrált környezetbarát megoldásait ismertesse. According to study, dealing with „responsible behaviour”, we can say that clarification of this concept is not easy, because literatures are not integrated. The various definitions are common in the respect that a healthy and sustainable balance should be created between economic interests, social expectations and environmental limits in the course of business. The socially responsible approach of a firm can be manifested through its actions One of these, increasingly popular research area is the study of responsible behavior in the sport sector. Undoubted, that all sports use natural resources in some measure and have an impact on natural environment. Expropriation of territory, affect of biodiversity, use of clean water, waste emission, building and operation of sports facilities, cuttering, producing and disposal of sports equipment multiply are those tasks, waiting for greening, that can and should be helped by responsible behaviour. The aim of our study is to present top sporting goods manufacturers’ – Nike, Adidas – environmentally friendly solution in the course of their manufacturer activity