197 research outputs found

    The deep history of the number words

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    We have previously shown that the ‘low limit’ number words (from one to five) have exceptionally slow rates of lexical replacement when measured across the Indo-European (IE) languages. Here, we replicate this finding within the Bantu and Austronesian language families, and with new data for the IE languages. Number words can remain stable for 10 000 to over 100 000 years, or around 3.5–20 times longer than average rates of lexical replacement among the Swadesh list of ‘fundamental vocabulary’ items. Ordinal evidence suggests that number words also have slow rates of lexical replacement in the Pama– Nyungan language family of Australia. We offer three hypotheses to explain these slow rates of replacement: (i) that the abstract linguistic-symbolic processing of ‘number’ links to evolutionarily conserved brain regions associated with numerosity; (ii) that number words are unambiguous and therefore have lower ‘mutation rates’; and (iii) that the number words occupy a region of the phonetic space that is relatively full and therefore resist change because alternatives are unlikely to be as ‘good’ as the original word. This article is part of a discussion meeting issue ‘The origins of numerical abilities’

    World-Wide Web scaling exponent from Simon's 1955 model

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    Recently, statistical properties of the World-Wide Web have attracted considerable attention when self-similar regimes have been observed in the scaling of its link structure. Here we recall a classical model for general scaling phenomena and argue that it offers an explanation for the World-Wide Web's scaling exponent when combined with a recent measurement of internet growth.Comment: 1 page RevTeX, no figure

    Feature selection and novelty in computational aesthetics

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    [Abstract] An approach for exploring novelty in expression-based evolutionary art systems is presented. The framework is composed of a feature extractor, a classifier, an evolutionary engine and a supervisor. The evolutionary engine exploits shortcomings of the classifier, generating misclassified instances. These instances update the training set and the classifier is re-trained. This iterative process forces the evolutionary algorithm to explore new paths leading to the creation of novel imagery. The experiments presented and analyzed herein explore different feature selection methods and indicate the validity of the approach.Portugal. Fundação para a CiĂȘncia e a Tecnologia; PTDC/EIA–EIA/115667/2009Galicia.ConsellerĂ­a de InnovaciĂłn, Industria e Comercio ; PGIDIT10TIC105008P

    Mechanical mode dependence of bolometric back-action in an AFM microlever

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    Two back action (BA) processes generated by an optical cavity based detection device can deeply transform the dynamical behavior of an AFM microlever: the photothermal force or the radiation pressure. Whereas noise damping or amplifying depends on optical cavity response for radiation pressure BA, we present experimental results carried out under vacuum and at room temperature on the photothermal BA process which appears to be more complex. We show for the first time that it can simultaneously act on two vibration modes in opposite direction: noise on one mode is amplified whereas it is damped on another mode. Basic modeling of photothermal BA shows that dynamical effect on mechanical mode is laser spot position dependent with respect to mode shape. This analysis accounts for opposite behaviors of different modes as observed

    Power-law distributions and Levy-stable intermittent fluctuations in stochastic systems of many autocatalytic elements

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    A generic model of stochastic autocatalytic dynamics with many degrees of freedom wiw_i i=1,...,Ni=1,...,N is studied using computer simulations. The time evolution of the wiw_i's combines a random multiplicative dynamics wi(t+1)=λwi(t)w_i(t+1) = \lambda w_i(t) at the individual level with a global coupling through a constraint which does not allow the wiw_i's to fall below a lower cutoff given by c⋅wˉc \cdot \bar w, where wˉ\bar w is their momentary average and 0<c<10<c<1 is a constant. The dynamic variables wiw_i are found to exhibit a power-law distribution of the form p(w)∌w−1−αp(w) \sim w^{-1-\alpha}. The exponent α(c,N)\alpha (c,N) is quite insensitive to the distribution Π(λ)\Pi(\lambda) of the random factor λ\lambda, but it is non-universal, and increases monotonically as a function of cc. The "thermodynamic" limit, N goes to infty and the limit of decoupled free multiplicative random walks c goes to 0, do not commute: α(0,N)=0\alpha(0,N) = 0 for any finite NN while α(c,∞)≄1 \alpha(c,\infty) \ge 1 (which is the common range in empirical systems) for any positive cc. The time evolution of wˉ(t){\bar w (t)} exhibits intermittent fluctuations parametrized by a (truncated) L\'evy-stable distribution Lα(r)L_{\alpha}(r) with the same index α\alpha. This non-trivial relation between the distribution of the wiw_i's at a given time and the temporal fluctuations of their average is examined and its relevance to empirical systems is discussed.Comment: 7 pages, 4 figure

    Interpretation of plasma amino acids in the follow-up of patients: the impact of compartmentation

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    Results of plasma or urinary amino acids are used for suspicion, confirmation or exclusion of diagnosis, monitoring of treatment, prevention and prognosis in inborn errors of amino acid metabolism. The concentrations in plasma or whole blood do not necessarily reflect the relevant metabolite concentrations in organs such as the brain or in cell compartments; this is especially the case in disorders that are not solely expressed in liver and/or in those which also affect nonessential amino acids. Basic biochemical knowledge has added much to the understanding of zonation and compartmentation of expressed proteins and metabolites in organs, cells and cell organelles. In this paper, selected old and new biochemical findings in PKU, urea cycle disorders and nonketotic hyperglycinaemia are reviewed; the aim is to show that integrating the knowledge gained in the last decades on enzymes and transporters related to amino acid metabolism allows a more extensive interpretation of biochemical results obtained for diagnosis and follow-up of patients and may help to pose new questions and to avoid pitfalls. The analysis and interpretation of amino acid measurements in physiological fluids should not be restricted to a few amino acids but should encompass the whole quantitative profile and include other pathophysiological markers. This is important if the patient appears not to respond as expected to treatment and is needed when investigating new therapies. We suggest that amino acid imbalance in the relevant compartments caused by over-zealous or protocol-driven treatment that is not adjusted to the individual patient's needs may prolong catabolism and must be correcte

    From Social Data Mining to Forecasting Socio-Economic Crisis

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    Socio-economic data mining has a great potential in terms of gaining a better understanding of problems that our economy and society are facing, such as financial instability, shortages of resources, or conflicts. Without large-scale data mining, progress in these areas seems hard or impossible. Therefore, a suitable, distributed data mining infrastructure and research centers should be built in Europe. It also appears appropriate to build a network of Crisis Observatories. They can be imagined as laboratories devoted to the gathering and processing of enormous volumes of data on both natural systems such as the Earth and its ecosystem, as well as on human techno-socio-economic systems, so as to gain early warnings of impending events. Reality mining provides the chance to adapt more quickly and more accurately to changing situations. Further opportunities arise by individually customized services, which however should be provided in a privacy-respecting way. This requires the development of novel ICT (such as a self- organizing Web), but most likely new legal regulations and suitable institutions as well. As long as such regulations are lacking on a world-wide scale, it is in the public interest that scientists explore what can be done with the huge data available. Big data do have the potential to change or even threaten democratic societies. The same applies to sudden and large-scale failures of ICT systems. Therefore, dealing with data must be done with a large degree of responsibility and care. Self-interests of individuals, companies or institutions have limits, where the public interest is affected, and public interest is not a sufficient justification to violate human rights of individuals. Privacy is a high good, as confidentiality is, and damaging it would have serious side effects for society.Comment: 65 pages, 1 figure, Visioneer White Paper, see http://www.visioneer.ethz.c
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