314 research outputs found
Estimating causal networks in biosphere–atmosphere interaction with the PCMCI approach
Local meteorological conditions and biospheric activity are tightly coupled. Understanding these links is an essential prerequisite for predicting the Earth system under climate change conditions. However, many empirical studies on the interaction between the biosphere and the atmosphere are based on correlative approaches that are not able to deduce causal paths, and only very few studies apply causal discovery methods. Here, we use a recently proposed causal graph discovery algorithm, which aims to reconstruct the causal dependency structure underlying a set of time series. We explore the potential of this method to infer temporal dependencies in biosphere-atmosphere interactions. Specifically we address the following questions: How do periodicity and heteroscedasticity influence causal detection rates, i.e. the detection of existing and non-existing links? How consistent are results for noise-contaminated data? Do results exhibit an increased information content that justifies the use of this causal-inference method? We explore the first question using artificial time series with well known dependencies that mimic real-world biosphere-atmosphere interactions. The two remaining questions are addressed jointly in two case studies utilizing observational data. Firstly, we analyse three replicated eddy covariance datasets from a Mediterranean ecosystem at half hourly time resolution allowing us to understand the impact of measurement uncertainties. Secondly, we analyse global NDVI time series (GIMMS 3g) along with gridded climate data to study large-scale climatic drivers of vegetation greenness. Overall, the results confirm the capacity of the causal discovery method to extract time-lagged linear dependencies under realistic settings. The violation of the method's assumptions increases the likelihood to detect false links. Nevertheless, we consistently identify interaction patterns in observational data. Our findings suggest that estimating a directed biosphere-atmosphere network at the ecosystem level can offer novel possibilities to unravel complex multi-directional interactions. Other than classical correlative approaches, our findings are constrained to a few meaningful set of relations which can be powerful insights for the evaluation of terrestrial ecosystem models
Colloids in light fields: particle dynamics in random and periodic energy landscapes
The dynamics of colloidal particles in potential energy landscapes have
mainly been investigated theoretically. In contrast, here we discuss the
experimental realization of potential energy landscapes with the help of light
fields and the observation of the particle dynamics by video microscopy. The
experimentally observed dynamics in periodic and random potentials are compared
to simulation and theoretical results in terms of, e.g. the mean-squared
displacement, the time-dependent diffusion coefficient or the non-Gaussian
parameter. The dynamics are initially diffusive followed by intermediate
subdiffusive behaviour which again becomes diffusive at long times. How
pronounced and extended the different regimes are, depends on the specific
conditions, in particular the shape of the potential as well as its roughness
or amplitude but also the particle concentration. Here we focus on dilute
systems, but the dynamics of interacting systems in external potentials, and
thus the interplay between particle-particle and particle-potential
interactions, is also mentioned briefly. Furthermore, the observed dynamics of
dilute systems resemble the dynamics of concentrated systems close to their
glass transition, with which it is compared. The effect of certain potential
energy landscapes on the dynamics of individual particles appears similar to
the effect of interparticle interactions in the absence of an external
potential
Recommended from our members
Guide to open access monograph publishing for arts, humanities and social science researchers
Recommended from our members
Guide to Creative Commons for Humanities and Social Science Monograph Authors
An output of the OAPEN-UK project, this guide explores concerns expressed in public evidence given by researchers, learned societies and publishers to inquiries in the House of Commons and the House of Lords, and also concerns expressed by researchers working with the OAPEN-UK project. We have also identified a number of common questions and have drafted answers, which have been checked by experts including Creative Commons. The guide has been edited by active researchers, to make sure that it is relevant and useful to academics faced with making decisions about publishing
Environmental management decision-making in certified hotels
This paper analyses environmental decision-making against two axes, motivations and decision-making processes, to understand the reasons for pro-environmental behaviour by the managements of Spanish Eco-management and Audit Scheme (EMAS)-certified hotels. Mixed methods were used to study perceptions of EMAS and reasons for being certified, with current and lapsed EMAS-certified firms triangulated against expert interviews and documentary evidence. Four groups of hotels were differentiated: Strategic hotels (22%) (with high levels of integrated environmental management), Followers (48%), Greenwashers (11%) and Laggers (19%) (with low levels of integrated environmental management). Most hotels were found to be internally driven in their purpose and ad hoc in their decision-making, with limited understanding of externally driven benefits and motivation for more systematic management systems. This questions the success of EMAS as both a continuous improvement management and as a market-based regulation tool for hotels. Few hotels overall related high environmental standards to the possibilities of gaining market advantage: most wished to avoid legal challenges. The paper also illustrates the ways in which hotels opportunistically switch certification systems to get what they see as a better deal. © 2011 Taylor & Francis
Glycated platelets proteome
Comunicaciones a congreso
Control of test particle transport in a turbulent electrostatic model of the Scrape Off Layer
The drift motion of charged test particle dynamics in
the Scrape Off Layer (SOL)is analyzed to investigate a transport control
strategy based on Hamiltonian dynamics. We model SOL turbulence using a 2D
non-linear fluid code based on interchange instability which was found to
exhibit intermittent dynamics of the particle flux. The effect of a small and
appropriate modification of the turbulent electric potential is studied with
respect to the chaotic diffusion of test particle dynamics. Over a significant
range in the magnitude of the turbulent electrostatic field, a three-fold
reduction of the test particle diffusion coefficient is achieved
Testing the relevance of effective interaction potentials between highly charged colloids in suspension
Combining cell and Jellium model mean-field approaches, Monte Carlo together
with integral equation techniques, and finally more demanding many-colloid
mean-field computations, we investigate the thermodynamic behavior, pressure
and compressibility of highly charged colloidal dispersions, and at a more
microscopic level, the force distribution acting on the colloids. The
Kirkwood-Buff identity provides a useful probe to challenge the
self-consistency of an approximate effective screened Coulomb (Yukawa)
potential between colloids. Two effective parameter models are put to the test:
cell against renormalized Jellium models
Combination of photodynamic therapy and oral antifungals for the treatment of onychomycosis
Onychomycosis accounts for 50% of nail disorders, making it one of the most prevalent fungal diseases and a therapeutic challenge. Photodynamic therapy (PDT) could constitute a therapeutic alternative, owing to its good adherence, the low probability of resistance, the lack of interaction with antimicrobials, and its favorable adverse effect profile. This retrospective observational study included all patients with a microbiological diagnosis of onychomycosis treated with PDT at Miguel Servet University Hospital, Zaragoza (Spain), between January 2013 and June 2021. The protocol con-sisted of pre-treatment with 40% urea for 7 days, followed by 16% methyl-aminolevulinate (MAL) for 3 h and subsequent irradiation with a red-light LED lamp (37 J/cm2), every 1 or 2 weeks. Combined treatment with oral and/or topical antifungals was recorded. Of the 20 patients included (mean age, 59 ± 17 years), 55% were men. The most frequently detected microorganism was Trichophyton rubrum (55%). The most commonly affected location was the feet (90%): 50% of these cases were associated with tinea pedis. The median (standard deviation) number of PDT sessions was 6 (2.8). PDT was combined with systemic terbinafine (250 mg/day) in 10 cases (in 8 cases, this was administered for only 1 month), and with topical terbinafine in 3 cases. A complete clinical response was achieved in 80% (16) of cases and microbiological cure in 60% (12). PDT is a therapeutic alternative for ony-chomycosis, and can be administered either in monotherapy or combined with antifungals, allowing for a reduction in the duration and possible adverse effects of antifungal treatment and achieving higher cure rates than those obtained with either treatment alone
Las emociones asociadas a la amistad cívica: una perspectiva psicoeducativa
The lack of social cohesion is a challenge for societies in our socio-political and cultural context. Although it is ambivalent, a way of promoting social cohesion is cultivating civic friendship. The aim of this article is twofold: to analyze the emotions associated with civic friendship, according to a hierarchical model presented by the authors; and to propose guidelines for its educational implementation, through actions that precede or goes hand in hand with the emotions. This work is theoretical and concludes that the specific emotions of civic friendship are the other-oriented emotions and that, paradoxically, being civic friendship an advantage friendship, it is educated by working on selfless emotions.La falta de cohesión social supone un reto para las sociedades de nuestro entorno sociopolítico y cultural. La amistad cívica, aunque tiene carácter ambivalente, puede ser una vía para afrontar este desafío. El objetivo del artículo es doble: analizar las emociones asociadas a la amistad cívica de acuerdo con un modelo jerárquico propio; y proponer orientaciones para su implementación educativa, mediante acciones concretas que preceden o acompañan a las emociones. Este trabajo es teórico y concluye que las emociones específicas de la amistad cívica son las emociones orientadas al otro y que, paradójicamente, siendo la amistad cívica ventajosa, se educa trabajando emociones desinteresadas
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