4,049 research outputs found

    Trophic consequences of introduced species: comparative impacts of increased inter-specific versus intra-specific competitive interactions

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    1. Invasive species can cause substantial ecological impacts on native biodiversity. Whilst ecological theory attempts to explain the processes involved in the trophic integration of invaders into native food webs and their competitive impacts on resident species, results are equivocal. In addition, quantifying the relative strength of impacts from non-native species (inter-specific competition) versus the release of native conspecifics (intra-specific competition) is important but rarely completed. 2. Two model non-native fishes, the globally invasive Cyprinus carpio and Carassius auratus, and the model native fish Tinca tinca, were used in a pond experiment to test how increased intra- and inter-specific competition influenced trophic niches and somatic growth rates. This was complemented by samples collected from three natural fish communities where the model fishes were present. The isotopic niche, calculated using stable isotope data, represented the trophic niche. 3. The pond experiment used additive and substitutive treatments to quantify the trophic niche variation that resulted from intra- and inter-specific competitive interactions. Although the trophic niche sizes of the model species were not significantly altered by any competitive treatment, they all resulted in patterns of inter-specific niche divergence. Increased inter-specific competition caused the trophic niche of T. tinca to shift to a significantly higher trophic position, whereas intra-specific competition caused its position to shift towards elevated 13C. These patterns were independent of impacts on fish growth rates, which were only significantly altered when inter-specific competition was elevated. 4. In the natural fish communities, patterns of trophic niche partitioning between the model fishes was evident, with no niche sharing. Comparison of these results with those of the experiment revealed the most similar results between the two approaches were for the niche partitioning between sympatric T. tinca and C. carpio. 5. These results indicate that trophic niche divergence facilitates the integration of introduced species into food webs, but there are differences in how this manifests between introductions that increase inter- and intra-specific competition. In entirety, these results suggest that the initial ecological response to an introduction appears to be a trophic re-organisation of the food web that minimises the trophic interactions between competing species

    Fresh perspectives for classic forest restoration challenges

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    Restoration ecology is a young scientific discipline whose limitations can compromise the recovery of ecosystem biodiversity and functions. Specifically for limitations on forest restoration, we first recommend considering measures prior to land use changes to deal with the common lack of efforts to anticipate and plan restoration. Second, we suggest using multiple references in restoration planning to avoid simplified reference characterization, and we advise assessing ecosystem recovery with indicators that better incorporate ecosystem complexity in recovery assessments. Finally, we propose initiatives to encourage scientific communication outside academia to diminish the communication gap between scientists and practitioners. © 2019 Society for Ecological RestorationA.R.U. was funded by Environmental Fellowship Programme of Tatiana Pérez de Guzmán el Bueno Foundation (2016) and María de Maeztu excellence accreditation (MDM-2017-0714) from the Spanish Government; V.C.A. by REMEDINAL4 (Madrid Government, TE-CM S2018/EMT-4338); Z.R. by the LafargeHolcim, FIRE Foundation, and UAH partnership; and L.M.B. by the FPI Fellowship (BES-2015-075276) from the Spanish Government

    Gender bias in ecosystem restoration: from science to practice

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    The declaration of the United Nations Decade on Ecosystem Restoration 2020–2030 has established the need to focus on human rights in restoration initiatives, including gender equality. Although this goal raises a need to monitor gender biases on ecosystem restoration, we still lack basic gender information and evaluations on the current situation. The main purpose of this study is to analyze gender bias in ecosystem restoration covering three dimensions: research, outreach, and practice. We used scientific publications from the Restoration Ecology journal, mentions of these articles in Altmetric Explorer and Twitter, and projects from the Society for Ecological Restoration's database. First, we study gender bias among people leading ecosystem restoration initiatives in the three dimensions. Second, we assessed factors that could influence gender bias, including year, target ecosystem, and socioeconomic country development. Third, we analyzed whether the impact of scientific knowledge in society depends on the gender of the scientific team. Our results indicate that men were primary leaders in research, outreach, and practice initiatives in ecosystem restoration. There seems to be a trend over time toward equality in research, but gender inequality is still present in most types of ecosystems, with women leading more projects in more developed countries. The impact of scientific knowledge is independent of the author's gender, but research of male senior authors seems to reach society more easily. This broad perspective of inequality in the three dimensions can evolve toward gender equality, by applying gender approaches in restoration policies and initiatives. © 2022 Society for Ecological Restoration.Raw data is publicly available thanks to Web of Science, Altmetrics, Twitter and SER. Data and scripts used for the analysis are available via Figshare (Cruz‐Alonso et al. 2022 ). Funding: V.C.‐A.—Real Colegio Complutense postdoc fellowship; A.R.‐U.—Spanish State Research Agency through María de Maeztu Excellence Unit accreditation 2018–2022 (MDM‐2017‐0714); L.M.—Swiss National Science Foundation (PCEFP2_181115) and a Margarita Salas Postdoctoral Fellowship from Universidad de Alcalá; L.M.‐B.—Ministerio de Ciencia e Innovación (PID2019‐106806GB‐I00) and a Margarita Salas Postdoctoral Fellowship from Universidad de Alcalá; N.M.—predoctoral grant from Universidad de Alcalá; E.V.‐A.—European Commission (project SHOWCASE, H2020: 862480). We appreciate the support of the FIRE Foundation and the comments of M. Almaraz, M. Pajares, A. S. Moya, and D. Rohrer to improve the manuscript.Raw data is publicly available thanks to Web of Science, Altmetrics, Twitter and SER. Data and scripts used for the analysis are available via Figshare (Cruz‐Alonso et al. 2022 ). Funding: V.C.‐A.—Real Colegio Complutense postdoc fellowship; A.R.‐U.—Spanish State Research Agency through María de Maeztu Excellence Unit accreditation 2018–2022 (MDM‐2017‐0714); L.M.—Swiss National Science Foundation (PCEFP2_181115) and a Margarita Salas Postdoctoral Fellowship from Universidad de Alcalá; L.M.‐B.—Ministerio de Ciencia e Innovación (PID2019‐106806GB‐I00) and a Margarita Salas Postdoctoral Fellowship from Universidad de Alcalá; N.M.—predoctoral grant from Universidad de Alcalá; E.V.‐A.—European Commission (project SHOWCASE, H2020: 862480). We appreciate the support of the FIRE Foundation and the comments of M. Almaraz, M. Pajares, A. S. Moya, and D. Rohrer to improve the manuscript

    Phase diagram of the (bosonic) Double-Exchange Model

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    The phase diagram of the simplest approximation to Double-Exchange systems, the bosonic Double-Exchange model with antiferromagnetic super-exchange coupling, is fully worked out by means of Monte Carlo simulations, large-N expansions and Variational Mean-Field calculations. We find a rich phase diagram, with no first-order phase transitions. The most surprising finding is the existence of a segment like ordered phase at low temperature for intermediate AFM coupling which cannot be detected in neutron-scattering experiments. This is signaled by a maximum (a cusp) in the specific heat. Below the phase-transition, only short-range ordering would be found in neutron-scattering. Researchers looking for a Quantum Critical Point in manganites should be wary of this possibility. Finite-Size Scaling estimates of critical exponents are presented, although large scaling corrections are present in the reachable lattice sizes.Comment: 17 pages, 14 figure

    Improving Cognitive Visual-Motor Abilities in Individuals with Down Syndrome

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    Down syndrome causes a reduction in cognitive abilities, with visual-motor skills being particularly affected. In this work, we have focused on this skill in order to stimulate better learning. The proposal relies on stimulating the cognitive visual-motor skills of individuals with Down Syndrome (DS) using exercises with a gestural interaction platform based on the KINECT sensor named TANGO:H, the goal being to improve them. To validate the proposal, an experimental single-case study method was designed using two groups: a control group and an experimental one, with similar cognitive ages. Didactic exercises were provided to the experimental group using visual cognitive stimulation. These exercises were created on the TANGO:H Designer, a platform that was designed for gestural interaction using the KINECT sensor. As a result, TANGO:H allows for visual-motor cognitive stimulation through the movement of hands, arms, feet and head. The “Illinois Test of Psycholinguistic Abilities (ITPA)” was applied to both groups as a pre-test and post-test in its four reference sections: visual comprehension, visual-motor sequential memory, visual association, and visual integration. Two checks were made, one using the longitudinal comparison of the pre-test/post-test of the experimental group, and another that relied on comparing the difference of the means of the pre-test/post-test. We also used an observational methodology for the working sessions from the experimental group. Although the statistical results do not show significant differences between the two groups, the results of the observations exhibited an improvement in visual-motor cognitive skills

    The U(1)-Higgs Model: Critical Behaviour in the Confinig-Higgs region

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    We study numerically the critical properties of the U(1)-Higgs lattice model, with fixed Higgs modulus, in the region of small gauge coupling where the Higgs and Confining phases merge. We find evidence of a first order transition line that ends in a second order point. By means of a rotation in parameter space we introduce thermodynamic magnitudes and critical exponents in close resemblance with simple models that show analogous critical behaviour. The measured data allow us to fit the critical exponents finding values in agreement with the mean field prediction. The location of the critical point and the slope of the first order line are accurately given.Comment: 21 text pages. 12 postscript figures available on reques

    The genomics of visuospatial neurocognition in obsessive-compulsive disorder: A preliminary GWAS

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    Background: The study of Obsessive-Compulsive Disorder (OCD) genomics has primarily been tackled by Genome-wide association studies (GWAS), which have encountered troubles in identifying replicable single nucleotide polymorphisms (SNPs). Endophenotypes have emerged as a promising avenue of study in trying to elucidate the genomic bases of complex traits such as OCD.Methods: We analyzed the association of SNPs across the whole genome with the construction of visuospatial information and executive performance through four neurocognitive variables assessed by the Rey-Osterrieth Complex Figure Test (ROCFT) in a sample of 133 OCD probands. Analyses were performed at SNP- and genelevel.Results: No SNP reached genome-wide significance, although there was one SNP almost reaching significant association with copy organization (rs60360940; P = 9.98E-08). Suggestive signals were found for the four variables at both SNP- (P < 1E-05) and gene-levels (P < 1E-04). Most of the suggestive signals pointed to genes and genomic regions previously associated with neurological function and neuropsychological traits. Limitations: Our main limitations were the sample size, which was limited to identify associated signals at a genome-wide level, and the composition of the sample, more representative of rather severe OCD cases than a population-based OCD sample with a broad severity spectrum.Conclusions: Our results suggest that studying neurocognitive variables in GWAS would be more informative on the genetic basis of OCD than the classical case/control GWAS, facilitating the genetic characterization of OCD and its different clinical profiles, the development of individualized treatment approaches, and the improvement of prognosis and treatment response

    Un modelo híbrido para el entrenamiento adaptativo basado en ejercicios

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    En el presente trabajo se propone una estrategia de ejercitación basada en un modelo híbrido que integra técnicas de Inteligencia Artificial, Bases de Datos y Programación Orientada a Objetos, donde los conceptos fundamentales son: Ejercicio Prototipo y Nivel de Complejidad. El ejercicio prototipo permite optimizar el código almacenado de una gran variedad de ejercicios del mismo tipo, mientras que el nivel de complejidad garantiza la adaptación del entrenamiento de acuerdo al nivel de preparación del estudiante. Para lograr la funcionalidad del modelo, se han definido diversas estructuras de representación del conocimiento que componen en tiempo de ejecución el enunciado y la solución al problema presentado, lo cual posibilita el diseño de ejercicios genéricos. Se incluye, además, el registro de todo el quehacer del aprendiz, de modo que puede servir de base para dar seguimiento a su proceso de aprendizaje y por consiguiente, para brindarle las recomendaciones necesarias. Con este modelo de entrenamiento se logra ofrecer una gran diversidad de ejercicios que apoyen la etapa de reforzamiento y eviten el uso repetitivo de los mismos ejercicios, adaptar la ejercitación a las necesidades del alumno y brindar una asesoría desde el punto de vista que éste es orientado durante su preparación.Red de Universidades con Carreras en Informática (RedUNCI

    Un modelo híbrido para el entrenamiento adaptativo basado en ejercicios

    Get PDF
    En el presente trabajo se propone una estrategia de ejercitación basada en un modelo híbrido que integra técnicas de Inteligencia Artificial, Bases de Datos y Programación Orientada a Objetos, donde los conceptos fundamentales son: Ejercicio Prototipo y Nivel de Complejidad. El ejercicio prototipo permite optimizar el código almacenado de una gran variedad de ejercicios del mismo tipo, mientras que el nivel de complejidad garantiza la adaptación del entrenamiento de acuerdo al nivel de preparación del estudiante. Para lograr la funcionalidad del modelo, se han definido diversas estructuras de representación del conocimiento que componen en tiempo de ejecución el enunciado y la solución al problema presentado, lo cual posibilita el diseño de ejercicios genéricos. Se incluye, además, el registro de todo el quehacer del aprendiz, de modo que puede servir de base para dar seguimiento a su proceso de aprendizaje y por consiguiente, para brindarle las recomendaciones necesarias. Con este modelo de entrenamiento se logra ofrecer una gran diversidad de ejercicios que apoyen la etapa de reforzamiento y eviten el uso repetitivo de los mismos ejercicios, adaptar la ejercitación a las necesidades del alumno y brindar una asesoría desde el punto de vista que éste es orientado durante su preparación.Red de Universidades con Carreras en Informática (RedUNCI
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