A review on polycyclic aromatic hydrocarbons distribution in freshwater ecosystems and their toxicity to benthic fauna

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds, found ubiquitously in all environmental compartments. PAHs are considered hazardous pollutants, being of concern to both the environmental and human health. In the aquatic environment, PAHs tend to accumulate in the sediment due to their high hydrophobicity, and thus sediments can be considered their ultimate sink. Concurrently, sediments comprise important habitats for benthic species. This raises concern over the toxic effects of PAHs to benthic communities. Despite PAHs have been the subject of several reviews, their toxicity to freshwater benthic species has not been comprehensively discussed. This review aimed to provide an overview on PAHs distribution in freshwater environments and on their toxicity to benthic fauna species. The distribution of PAHs between sediments and the overlying water column, given by the sediment-water partition coefficient, revealed that PAHs concentrations were 2 to 4 orders of magnitude higher in sediments than in water. The sediment-water partition coefficient was positively correlated to PAHs hydrophobicity. Toxicity of PAHs to benthic fauna was addressed through Species Sensitivity Distributions. The derived hazardous concentration for 5% of the species (HC5) decreased as follows: NAP (376 μg L-1) > PHE > PYR > FLT > ANT (0.854 μg L-1), varying by 3 orders of magnitude. The hazardous concentrations (HC5) to benthic species were inversely correlated to the hydrophobicity of the individual PAHs. These findings are pertinent for environmental risk assessment of these compounds. This review also identified future challenges regarding the environmental toxicity of PAHs to freshwater benthic communities, namely the need for updating the PAHs priority list and the importance of comprehensively and more realistically assess the toxicity of PAHs in combination with other stressors, both chemical and climate-related.publishe

Optimal Self-Organization

We present computational and analytical results indicating that systems of driven entities with repulsive interactions tend to reach an optimal state associated with minimal interaction and minimal dissipation. Using concepts from non-equilibrium thermodynamics and game theoretical ideas, we generalize this finding to an even wider class of self-organizing systems which have the ability to reach a state of maximal overall ``success''. This principle is expected to be relevant for driven systems in physics like sheared granular media, but it is also applicable to biological, social, and economic systems, for which only a limited number of quantitative principles are available yet.Comment: This is the detailled revised version of a preprint on ``Self-Organised Optimality'' (cond-mat/9903319). For related work see http://www.theo2.physik.uni-stuttgart.de/helbing.html and http://angel.elte.hu/~vicsek

Learning curve and factors influencing successful robot-assisted bilateral sentinel lymph node mapping in early-stage cervical cancer: an observational cohort study

OBJECTIVES: To evaluate whether a learning curve affects the bilateral sentinel lymph node (SLN) detection in early-stage cervical cancer. METHODS: All patients with FIGO (2018) stage IA1-IB2 or IIA1 cervical cancer who had undergone robot-assisted SLN mapping performed with a combination of preoperative technetium-99m nanocolloids (including preoperative imaging) and intraoperative blue dye were retrospectively included. Risk-adjusted cumulative sum (RA-CUSUM) analysis was used to determine if a learning curve based on bilateral SLN detection existed in this cohort. RESULTS: A total of 227 cervical cancer patients were included. In 98.2% of patients (223/227) at least one SLN was detected. The bilateral SLN detection rate was 87.2% (198/227). Except for age (OR 1.06 per year, 95%CI 1.02-1.09), no significant risk factors for non-bilateral SLN detection were found (e.g., prior conization, BMI or FIGO stage). The RA-CUSUM analysis showed no clear learning phase during the first procedures and cumulative bilateral detection rate remained at least 80% during the entire inclusion period. CONCLUSIONS: In this single-institution experience, we observed no learning curve affecting robot-assisted SLN mapping using a radiotracer and blue dye in early-stage cervical cancer patients, with stable bilateral detection rates of at least 80% when adhering to a standardized methodology

ScenaLand: a simple methodology for developing land use and management scenarios

Scenarios serve science by testing the sensitivity of a system and/or society to adapt to the future. In this study, we present a new land use scenario methodology called ScenaLand. This methodology aims to develop plausible and contrasting land use and management (LUM) scenarios, useful to explore how LUM (e.g. soil and water conservation techniques) may afect ecosystem services under global change in a wide range of environments. ScenaLand is a method for constructing narrative and spatially explicit land use scenarios that are useful for end-users and impact modellers. This method is innovative because it merges literature and expert knowledge, and its low data requirement makes it easy to be implemented in the context of inter-site comparison, including global change projections. ScenaLand was developed and tested on six diferent Mediterranean agroecological and socioeconomic contexts during the MASCC research project (Mediterranean agricultural soil conservation under global change). The method frst highlights the socioeconomic trends of each study site including emerging trends such as new government laws, LUM techniques through a qualitative survey addressed to local experts. Then, the method includes a ranking of driving factors, a matrix about land use evolution, and soil and water conservation techniques. ScenaLand also includes a framework to develop narratives along with two priority axes (contextualized to environmental protection vs. land productivity in this study). In the context of this research project, four contrasting scenarios are proposed: S1 (business-as-usual), S2 (market-oriented), S3 (environmental protection), and S4 (sustainable). Land use maps are then built with the creation of LUM allocation rules based on agroecological zoning. ScenaLand resulted in a robust and easy method to apply with the creation of 24 contrasted scenarios. These scenarios come not only with narratives but also with spatially explicit maps that are potentially used by impact modellers and other endusers. The last part of our study discusses the way the method can be implemented including a comparison between sites and the possibilities to implement ScenaLand in other contexts.info:eu-repo/semantics/publishedVersio

Runoff and inter-rill erosion in a maritime pine and a eucalypt plantation following wildfire and terracing in north-central portugal

The purpose of this study was to assess how terracing affected overland\nflow and associated sediment losses, at the micro-plot scale (0.25\nm(2)), in recently burnt stands of the two principal forest types in\nnorth-central Portugal, i.e. mono-specific stands of Maritime Pine and\nEucalypt. Terracing is an increasingly common practice of slope\nengineering in the study region but its impacts on runoff and erosion\nare poorly studied. Non-terraced plots at the Eucalypt and the Pine site\nrevealed similar median runoff coefficients (rc: 20-30%) as well as\ncomparable median sediment losses (15-25 g m(-2)) during the first seven\nmonths following wildfire. During the ensuing, slightly wetter 18-month\nperiod, however, non-terraced plots at the Pine site lost noticeably\nmore sediments (in median, 90 vs. 18 g m(-2)), in spite the runoff\nresponse had remained basically the same (median rc: 33 vs. 28%). By\ncontrast, terraced plots at the same Pine site lost hugely more\nsediments (in median, 1,200 g m(-2)) during this 18-month period.\nTerraced plots at the Eucalypt site even lost three times more sediments\n(in median, 3,600 g m(-2)). Ground cover and resistance to shear stress\nseemed to be key factors in the observed/inferred impacts of terracing.The present study was carried out in the framework of the FIRECNUTS project (PTDC/AGRCFL/104559/2008), funded by the FCT/MCTES (PIDDAC), with co-funding by FEDER through COMPETE (Programa Operacional Factores de Competitividade; POFC), and with support of the research grants, attributed by FCT/MCTES, of SPA (SFRH/BD/ 33392/2008), SRF (SFRH/BD/75562/2010) and METV (SFRH/BPD/63808/ 2009). We further gratefully acknowledge the help of Margarida Caria, Raquel Ferreira, Ana Heitor, Stefan Van den Heuvel, Maruxa Malvar, Robbert de Lenne, Ton van der Linden, Max Shu Fen Sheng, Iryna Skulska, Hein Vermin and Jovana Vilimonovic with field data and sample collection and/or with laboratory analysis of the runoff samples. Finally, we are much obliged to the two anonymous reviewers for their contribution in improving the original manuscript.publishe

Cooperation, Norms, and Revolutions: A Unified Game-Theoretical Approach

Cooperation is of utmost importance to society as a whole, but is often challenged by individual self-interests. While game theory has studied this problem extensively, there is little work on interactions within and across groups with different preferences or beliefs. Yet, people from different social or cultural backgrounds often meet and interact. This can yield conflict, since behavior that is considered cooperative by one population might be perceived as non-cooperative from the viewpoint of another. To understand the dynamics and outcome of the competitive interactions within and between groups, we study game-dynamical replicator equations for multiple populations with incompatible interests and different power (be this due to different population sizes, material resources, social capital, or other factors). These equations allow us to address various important questions: For example, can cooperation in the prisoner's dilemma be promoted, when two interacting groups have different preferences? Under what conditions can costly punishment, or other mechanisms, foster the evolution of norms? When does cooperation fail, leading to antagonistic behavior, conflict, or even revolutions? And what incentives are needed to reach peaceful agreements between groups with conflicting interests? Our detailed quantitative analysis reveals a large variety of interesting results, which are relevant for society, law and economics, and have implications for the evolution of language and culture as well

Reductions in soil surface albedo as a function of biochar application rate: implications for global radiative forcing

Biochar can be defined as pyrolysed (charred) biomass produced for application to soils with the aim of mitigating global climate change while improving soil functions. Sustainable biochar application to soils has been estimated to reduce global greenhouse gas emissions by 71–130 Pg CO2-Ce over 100 years, indicating an important potential to mitigate climate change. However, these estimates ignored changes in soil surface reflection by the application of dark-coloured biochar. Through a laboratory experiment we show a strong tendency for soil surface albedo to decrease as a power decay function with increasing biochar application rate, depending on soil moisture content, biochar application method and land use. Surface application of biochar resulted in strong reductions in soil surface albedo even at relatively low application rates. As a first assessment of the implications for climate change mitigation of these biochar–albedo relationships, we applied a first order global energy balance model to compare negative radiative forcings (from avoided CO2 emissions) with positive radiative forcings (from reduced soil surface albedos). For a global-scale biochar application equivalent to 120 t ha−1, we obtained reductions in negative radiative forcings of 5 and 11% for croplands and 11 and 23% for grasslands, when incorporating biochar into the topsoil or applying it to the soil surface, respectively. For a lower global biochar application rate (equivalent to 10 t ha−1), these reductions amounted to 13 and 44% for croplands and 28 and 94% for grasslands. Thus, our findings revealed the importance of including changes in soil surface albedo in studies assessing the net climate change mitigation potential of biochar, and we discuss the urgent need for field studies and more detailed spatiotemporal modelling.We thank L Montanarella (Joint Research Centre) for making this study possible, W Mehl for help with the spectroscopy work and P Drahota for the mineralogy analyses. We thank the Portuguese Fundação para a Ciência e a Tecnologia (FCT) for providing F G A Verheijen with a postdoctoral grant (SFRH/BPD/74108/2010), and further want to acknowledge the financial support of the Czech Science Foundation (under grant No. GA 526/09/1762), and the Marie Curie CIG grant (No. GA 526/09/1762). We thank two anonymous reviewers for strengthening the letter.publishe

Superconducting spintronics

The interaction between superconducting and spin-polarized orders has recently emerged as a major research field following a series of fundamental breakthroughs in charge transport in superconductor-ferromagnet heterodevices which promise new device functionality. Traditional studies which combine spintronics and superconductivity have mainly focused on the injection of spin-polarized quasiparticles into superconducting materials. However, a complete synergy between superconducting and magnetic orders turns out to be possible through the creation of spin-triplet Cooper pairs which are generated at carefully engineered superconductor interfaces with ferromagnetic materials. Currently, there is intense activity focused on identifying materials combinations which merge superconductivity and spintronics in order to enhance device functionality and performance. The results look promising: it has been shown, for example, that superconducting order can greatly enhance central effects in spintronics such as spin injection and magnetoresistance. Here, we review the experimental and theoretical advances in this field and provide an outlook for upcoming challenges related to the new concept of superconducting spintronics.J.L. was supported by the Research Council of Norway, Grants No. 205591 and 216700. J.W.A.R. was supported by the UK Royal Society and the Leverhulme Trust through an International Network Grant (IN-2013-033).This is the accepted manuscript. The final version is available at http://www.nature.com/nphys/journal/v11/n4/full/nphys3242.html