1,612 research outputs found

    First Steps Towards a Runtime Comparison of Natural and Artificial Evolution

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    Evolutionary algorithms (EAs) form a popular optimisation paradigm inspired by natural evolution. In recent years the field of evolutionary computation has developed a rigorous analytical theory to analyse their runtime on many illustrative problems. Here we apply this theory to a simple model of natural evolution. In the Strong Selection Weak Mutation (SSWM) evolutionary regime the time between occurrence of new mutations is much longer than the time it takes for a new beneficial mutation to take over the population. In this situation, the population only contains copies of one genotype and evolution can be modelled as a (1+1)-type process where the probability of accepting a new genotype (improvements or worsenings) depends on the change in fitness. We present an initial runtime analysis of SSWM, quantifying its performance for various parameters and investigating differences to the (1+1)EA. We show that SSWM can have a moderate advantage over the (1+1)EA at crossing fitness valleys and study an example where SSWM outperforms the (1+1)EA by taking advantage of information on the fitness gradient

    THE REVEALED COMPETITIVENESS INDEX COMPARISON BETWEEN PERU AND MAIN WORLD EXPORTERS The case of Lambayeque Region

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    This paper presents and applies a conceptual framework to regional Competitiveness using the Index of revealed competitiveness introduced by Balassa in 1965 for the Lambayeque Region in the northern part of Peru with the end to determine the products more competitive of this region. In the first part of the article the competitiveness review is presented from the Porter approach to Systemic Competitiveness. The advantage of this method is to identify the competitiveness of the regional products and services as a function of the import and export values of the country in contrast with the same values of the other countries in the world. The FAOSTAT data is used for that purpose. The results shown that the crop most competitive are the avocados, the bananas, mangoes, asparagus, dry chilies and coffee. Nevertheless when these products are compare with others countries such as Chile and Brazil only mangoes and asparagus are strongly competitive. However both products are considered commodities rather than value added products and its competitiveness lies in comparative advantage such as clime and soil.Agribusiness; competitiveness; export; trade; partnership.

    On the reduction of 4-oxo-4h-benzopyran-3-carbaldehydes : global and local electrophilicity patterns

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    The theoretical global and local electrophilicity patterns of substituted and chelated 4-oxo-4H-benzopyran-3-carbaldehydes (formylchromones) have been evaluated using the electrophilicity index proposed by Parr et al [J. Am. Chem. Soc. 1999, 121, 1922]. The complexation of formylchromones with aluminum predicts a strong electrophilic character of these compounds against nucleophiles. Local response at the active sites may also be assessed in terms of a global contribution described by the global electrophilicity, and a local contribution described by the variations in electrophilic Fukui function at those sites. The highest local electrophilicity is found at the formyl group of the chelated formylchromones, in spite of that, the highest positive charge is located on the pyrone carbonyl group. This result is consistent with the experimental observed reactivity displayed by 4-oxo-4H-benzopyran-3-carbaldehydes in the presence of 2-propanol and alumina

    A Computational View on Natural Evolution: On the Rigorous Analysis of the Speed of Adaptation

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    Inspired by Darwin’s ideas, Turing (1948) proposed an evolutionary search as an automated problem solving approach. Mimicking natural evolution, evolutionary algorithms evolve a set of solutions through the repeated application of the evolutionary operators (mutation, recombination and selection). Evolutionary algorithms belong to the family of black box algorithms which are general purpose optimisation tools. They are typically used when no good specific algorithm is known for the problem at hand and they have been reported to be surprisingly effective (Eiben and Smith, 2015; Sarker et al., 2002). Interestingly, although evolutionary algorithms are heavily inspired by natural evolution, their study has deviated from the study of evolution by the population genetics community. We believe that this is a missed opportunity and that both fields can benefit from an interdisciplinary collaboration. The question of how long it takes for a natural population to evolve complex adaptations has fascinated researchers for decades. We will argue that this is an equivalent research question to the runtime analysis of algorithms. By making use of the methods and techniques used in both fields, we will derive plenty of meaningful results for both communities, proving that this interdisciplinary approach is effective and relevant. We will apply the tools used in the theoretical analysis of evolutionary algorithms to quantify the complexity of adaptive walks on many landscapes, illustrating how the structure of the fitness landscape and the parameter conditions can impose limits to adaptation. Furthermore, as geneticists use diffusion theory to track the change in the allele frequencies of a population, we will develop a brand new model to analyse the dynamics of evolutionary algorithms. Our model, based on stochastic differential equations, will allow to describe not only the expected behaviour, but also to measure how much the process might deviate from that expectation

    Reflexiones de un futuro profesor de Física y Química

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    En el presente Trabajo Fin de Máster se recogen las competencias adquiridas durante la realización del mismo, así como las principales conclusiones y reflexiones que dicho máster ha provocado

    Técnicas de aprendizaje supervisado en la enfermedad de Alzheimer. Aplicaciones al estudio ADNI

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    En este trabajo hemos empleando técnicas de Minería de Datos sobre la base de datos del proyecto Alzheimer’s Disease Neuroimaging Initiative (ADNI) con el objetivo de encontrar patrones en el seguimiento de los pacientes con la enfermedad de Alzheimer. El objetivo es realizar un diagnóstico del estado de la enfermedad y una predicción futura sobre si habrá conversión a una etapa más avanzada de la enfermedad. En el primer caso obtuvimos resultados excelentes con precisiones de hasta 90% y valores del área bajo la curva ROC (AUC) superiores a 0.94, en el segundo problema obtuvimos precisiones del 78% y AUC de 0.8 en predicciones a 6-12 meses vista, mientras que para previsiones a más largo plazo la precisión se redujo a unos valores entre el 55 y el 75% y el AUC entre 0.63 y 0.76

    Tomato-antioxidants enhance viability of L. reuteri under gastrointestinal conditions while the probiotic negatively affects bioaccessibility of lycopene and phenols

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    [EN] Changes undergone by tomato-antioxidants during gastrointestinal digestion of raw and fried tomato, with or without presence of the probiotic Lactobacillus reuteri ATCC 55730, were studied. Frying process enhanced the extractability of antioxidant compounds, being their content higher in fried than in raw tomato. In vitro digestion led to a significant loss of antioxidant activity (65 and 75% losses for raw and fried tomato, respectively), and total lycopene (60 and 50% losses for raw and fried tomato, respectively); and promoted trans-cis lycopene isomerization initiated during frying. Bioaccessibility of the antioxidant compounds was within 10% and 30%, being higher for phenolic compounds in raw tomato but lower for total lycopene. Finally, although the presence of Lactobacillus reuteri ATCC 55730 reduced the bioaccessibility of antioxidant compounds, the results suggests that the tomato's antioxidant compounds could have a protective effect against the loss of viability of the probiotic.Authors thanks the Universitat Politecnica de Valencia for the financial support given the research project "Simulacion gastrointestinal para el estudio de las interacciones "ingrediente funcional-matriz alimentaria" y su influencia sobre la biodisponibilidad y funcionalidad" (ref. number: 2814).García Hernández, J.; Hernández Pérez, M.; Peinado Pardo, I.; Andrés Grau, AM.; Heredia Gutiérrez, AB. (2018). Tomato-antioxidants enhance viability of L. reuteri under gastrointestinal conditions while the probiotic negatively affects bioaccessibility of lycopene and phenols. Journal of Functional Foods. 43:1-7. doi:https://doi.org/10.1016/j.jff.2017.12.052S174

    Balance deficiencies in women with fibromyalgia assessed using computerised dynamic posturography: a cross-sectional study in Spain

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    Objectives Our aims were (1) to compare the sensory organisation of balance control and balance strategies between women with fibromyalgia (FM) and healthy women; (2) to investigate which sensory component, that is, vestibular, visual or somato-sensory, is the most affected in FM and (3) to determine the associations between the functional independence measure (FIM) and balance responses in FM. Design Cross-sectional observational study. Setting Urban regional hospital and university (Universidad Rey Juan Carlos, Madrid, Spain). Participants Twenty women with FM and 20 matched healthy women. Primary/secondary outcome measures The sensory organisation test (SOT) was used to determine postural sway and balance during six different conditions with subjects in a standing position. The FIM was used to determine the level of functional independence in daily life activities (ADL). Between-group differences were analysed with analysis of covariance, and the Spearman's test was used for correlations. Results Significant differences between-groups and between-conditions were found for all SOT conditions (all, p<0.001): women with FM showed lower scores being the vestibular score the most affected. Different correlations between SOT conditions and some specific ADL were observed in the FM group: bathing activity and balance condition 6 (rs=0.541; p<0.001), bed transfers activity and conditions 2 (rs=0.491; p<0.001) and 3 (rs=0.510; p<0.001), positioning strategy six and dressing the upper (rs=0.530; p<0.001) or lower (rs=0.562; p<0.001) body, and toileting (rs=0.521; p<0.001): the greater the loss of balance, the greater the interference on some daily life activities. Conclusions Women with FM exhibited balance deficiencies and used different strategies for maintaining their balance in standing, which was associated with a negative impact on functional independence

    'Being normal' and self-identity: the experience of volunteering in individuals with severe mental disorders-a qualitative study

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    OBJECTIVE: This study sought to explore the views and experiences of a group of people with severe mental disorders (SMDs) who performed volunteer services. DESIGN: A qualitative phenomenological study. SETTING: Community public mental health services of the Community of Madrid and the province of Barcelona (Spain). PARTICIPANTS: Purposive sampling techniques were used between September 2016 and April 2017. The inclusion criteria were: individuals aged 18-65 years who participated in volunteer activities during the performance of this study, based on the regulations of volunteer services in Spain and the community of Madrid; a diagnosis of non-organic psychotic disorder (F20.x, F21, F22, F24, F25, F28, F29, F31.x, F32.3 and F33) according to the International Classification of Diseases, 10th Revision; an evolution of ?2 years; and a moderate to severe dysfunction of global functioning with scores ?70 in the Global Assessment of Functioning Scale. Ultimately, 23 people with SMD participated in the study with a mean age of 47 years (SD 8.23). METHODS: Data were collected through in-depth interviews and researcher field notes. A thematic analysis was performed following appropriate guidelines for qualitative research. RESULTS: Two main themes emerged to describe the experience of participating in volunteer activities: (1) rebuilding self-identity, based on the participant's experience of volunteering, of acquiring a new role and a new perceived identity that made them feel valued and respected; and (2) being a so-called normal person with a 'normal' life, based on recovering a sense of normality, unmarked by the illness, thanks to daily responsibilities and occupations. CONCLUSIONS: Qualitative research offers insight into the way people with SMD experience volunteering and may help to improve understanding of the underlying motivations that drive these individuals. These findings may be applied to improve guidance during their process of recovery and subsequent inclusion into society
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