Overlapping modularity at the critical point of k-clique percolation

One of the most remarkable social phenomena is the formation of communities in social networks corresponding to families, friendship circles, work teams, etc. Since people usually belong to several different communities at the same time, the induced overlaps result in an extremely complicated web of the communities themselves. Thus, uncovering the intricate community structure of social networks is a non-trivial task with great potential for practical applications, gaining a notable interest in the recent years. The Clique Percolation Method (CPM) is one of the earliest overlapping community finding methods, which was already used in the analysis of several different social networks. In this approach the communities correspond to k-clique percolation clusters, and the general heuristic for setting the parameters of the method is to tune the system just below the critical point of k-clique percolation. However, this rule is based on simple physical principles and its validity was never subject to quantitative analysis. Here we examine the quality of the partitioning in the vicinity of the critical point using recently introduced overlapping modularity measures. According to our results on real social- and other networks, the overlapping modularities show a maximum close to the critical point, justifying the original criteria for the optimal parameter settings.Comment: 20 pages, 6 figure

Agri-Environmental Soil Quality Indicator in the European Perspective

Soil quality is an account of the soil¿s ability to provide ecosystem and social services through its capacities to perform its functions under changing conditions (after Tóth et al. 2007.) The concept of soil quality expressed by this definition allows practical applications with regards to targeted social and/or ecosystem services, including agri-environmental services. The Thematic Strategy for Soil Protection of the European Union (COM 2006/231) identifies key soil functions of which the maintenance and improvement have to be considered in soil-related policies of the EU. Among the main soil functions several have agri-environmental relevance, which has to be taken into account when developing an Agri-environmental Soil Quality Indicator (AE-SQI). For agronomic purposes the biomass production function of soil is of absolute importance. This function, however, can be performed under varying external influences. The two main factors conditioning the performance of biomass production of soil are climate and management. During the evaluation of production function, the reacting capacities of soil to these factors need to be considered. Indication of soil quality from environmental point of view in the agricultural context can relate to off side environmental effects of soil condition and land management practices. The soil¿s capacity to store, filter and transform substances is crucial in this perspective (e.g. carbon storage and climate change; buffering capacity and diffuse contamination). Soil biodiversity can indicate local environmental quality. Based on the above concept an agri-environmental soil quality indicator is being developed for application in the European Union. The agri-environmental soil quality is expressed by an index constituted by four sub indicators: ¿ Productivity index (the capacity of soil to biomass production) ¿ Fertilizer response rate (input change / yield increase ratio) ¿ Production stability index (the soil-response to climatic variability) ¿ Soil environmental quality index (to express environmental aspects of SQ) The four sub indicators cover both agronomic and environmental aspects of the goodness of soil (soil quality), therefore constitute to a comprehensive agri-environmental soil quality indicator, which might be applied on different spatial and temporal scales. The proposed soil quality indicator can be used for policy development (including agricultural and soil protection policies) and monitoring through its capacity: - to indicate the effect of land use change (marginalization; soil sealing etc.) on the availability and functioning capacity of soil resources; - to indicate the effect of land management (e.g. intensification) on the functioning capacity of soil resources; - to indicate the effect of climatic variability on the production function of soil resources; - to indicate the capacity of soil to mitigate environmental problems (climate change, water pollution etc.). Based on the information provided by the AE-SQI and its sub-indicators, current levels of soil agri-environmental services can be assessed, monitored and future levels of such services can be projected.JRC.H.7-Land management and natural hazard

Threats to Soil Quality in Europe

During the recent years, there has been a surge of concern and attention in Europe to soil degradation processes. One of the most innovative aspects of the newly proposed Soil Thematic Strategy for the EU is the recognition of the multifunctionality of soils. This report is summarizing the reserch results on the fields of soil degradation and soil quality reserach. Chapters of the report include: Preface Characterisation of soil degradation risk: an overview Soil quality in the European Union Main threats to soil quality in Europe The Natural Susceptibility on European Soils to Compaction Soil Erosion: a main threats to the soils in Europe Soil Erosion risk assessment in the alpine area according to the IPCC scenarios An example of the threat of wind erosion using DSM techniques Updated map of salt affected soils in the European Union A framework to estimate the distribution of heavy metals in European Soils Application of Soil Organic Carbon Status Indicators for policy-decision making in the EU Main threats on soil biodiversity: The case of agricultural activities impacts on soil microarthropods Implications of soil threats on agricultural areas in Europe MEUSIS, a Multi-Scale European Soil Information System (MEUSIS): novel ways to derive soil indicators through UpscalingJRC.H.7-Land management and natural hazard

Soil Quality and Sustainability Evaluation - an Integrated Approach to Support Soil-Related Policies in the European Union - A JRC Position Paper

In the context of the policies of the European Union the purposes of soil quality descriptions can be on the one hand represented by the performed functions of the soil, which correspond to the land use goals. With the consideration of soil dynamics through responses to human or natural impacts on the other hand, a complex approach is achieved that gives a solid ground to evaluate and relate the quality of soil according to the requirements of sustainability. Therefore functions and responses are considered in our soil quality perception with special regards to major degradation threats, which are in the focus of the Thematic Strategy for Soil Protection in the European Union. Concept and definitions in the soil quality domain (soil quality, soil threath index, soil sustainability index etc.) are given in the report. The report provides a framework for soil quality and sustainability evaluation, that can be applied in variouse planning and decision making procedures.JRC.H.7-Land management and natural hazard

Land Quality and Landscape Processes

This monograph contains a selection of scientific papers presented on the conference on Land Quality and Landscape Processes, hold in Keszthely, Hungary. It covers topics related to various aspects of land quality including : concepts of assessment; evaluation of biomass productivity ; bioindicators of land quality ; quality assessment of degraded land ; land use related data processingJRC.H.5-Land Resources Managemen

Opportunities and challenges of bio-based fertilizers utilization for improving soil health

Bio-based fertilizers (BBFs) have been promoted as a solution to help manage bio-waste problems and improve soil health conditions. Their potential is to replace mineral fertilizers due to nonrenewable energy dependency and the accumulation that threatens environmental issues. Currently, laboratory and field-based literature have been growing since European Union (EU) looks BBFs as the future of agriculture bio-based products. Nevertheless, it is worth to summarizing the results on a regular basis. The added value of this work is to study the opportunities of bio-based fertilizer utilization to sustain plant productivity and investigate the challenges to water footprints and human health. This study found that contamination of heavy metals and pathogens is the main problems of BBFs implementation which need more attention to develop the technology process including the environmental risk assessments. Furthermore, compared to mineral fertilizers, BBFs have obstacles to getting social acceptance due to the challenges of transportation and production cost, the concentration of nutrients, matching crops, and policy framework. To sum up, BBF is a long-run scheme that should be started to tackle global issues since the potency as energy alternative sources to support the circular economy paradigm

Soils of the European Union

This report make a detailed summary of the soil resources of the EU. Contents: Acknowledgements 2 1. Introduction 3 2. Materials and methods 4 2.1 Soil Geographical Database of Eurasia at scale 1:1,000,000 (SGDBE) 4 2.2 Nomenclature of soil types 6 2.3 Map legend and representation 6 3. Soils of the European Union: an overview 8 4. Spatial distribution of the major soils in the European Union 11 4.1 Acrisols 11 4.2 Albeluvisols 13 4.3 Andosols 15 4.4 Anthrosols 17 4.5 Arenosols 19 4.6 Calcisols 21 4.7 Cambisols 23 4.8 Chernozems 25 4.9 Fluvisols 27 4.10 Gleysols 29 4.11 Gypsisols 31 4.12 Histosols 33 4.13 Kastanozems 35 4.14 Leptosols 37 4.15 Luvisols 39 4.16 Phaeozems 41 4.17 Planosol 43 4.18 Podzols 45 4.19 Regosols 47 4.20 Solonchaks 49 4.21 Solonetz 51 4.22 Umbrisols 53 4.23 Vertisols 55 5. Concluding remarks 57 References 58 Appendix 1. 59 Appendix 2. 62JRC.H.7-Land management and natural hazard

The ultrastructure and flexibility of thylakoid membranes in leaves and isolated chloroplasts as revealed by small-angle neutron scattering

We studied the periodicity of the multilamellar membrane system of granal chloroplasts in different isolated plant thylakoid membranes, using different suspension media, as well as on different detached leaves and isolated protoplasts—using small-angle neutron scattering. Freshly isolated thylakoid membranes suspended in isotonic or hypertonic media, containing sorbitol supplemented with cations, displayed Bragg peaks typically between 0.019 and 0.023 Å− 1, corresponding to spatially and statistically averaged repeat distance values of about 275–330 Å. Similar data obtained earlier led us in previous work to propose an origin from the periodicity of stroma thylakoid membranes. However, detached leaves, of eleven different species, infiltrated with or soaked in D2O in dim laboratory light or transpired with D2O prior to measurements, exhibited considerably smaller repeat distances, typically between 210 and 230 Å, ruling out a stromal membrane origin. Similar values were obtained on isolated tobacco and spinach protoplasts. When NaCl was used as osmoticum, the Bragg peaks of isolated thylakoid membranes almost coincided with those in the same batch of leaves and the repeat distances were very close to the electron microscopically determined values in the grana. Although neutron scattering and electron microscopy yield somewhat different values, which is not fully understood, we can conclude that small-angle neutron scattering is a suitable technique to study the periodic organization of granal thylakoid membranes in intact leaves under physiological conditions and with a time resolution of minutes or shorter. We also show here, for the first time on leaves, that the periodicity of thylakoid membranes in situ responds dynamically to moderately strong illumination. This article is part of a Special Issue entitled: Photosynthesis research for sustainability: Keys to produce clean energy