1,690 research outputs found

    Hidden, Moved, Forgotten: The Building Of The Dam El Zapotillo En Jalisco, Mexico

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    Can a small village of 500 inhabitants resist the joint attacks of their country's government and those of several multinationals? This article will analyze the social emergency raised in Temacapulín, a small town in Jalisco, Mexico, against the government's desire to build a mega dam to bring water to remote cities, which would mean the disappearance of the village and the displacement of its inhabitants. The ethnographic work shows that the resistance of the villagers brings to light the existence of different ways of managing water, linked to different conceptions of water itself, the rest of nature, and of how relations between human beings should be developed. The resulting political conflict shows as well how these different positions conceal distinct ideas about where human dignity resides, and what and which are the rights of men and women.19413715

    SSA of biomedical signals: A linear invariant systems approach

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    Singular spectrum analysis (SSA) is considered from a linear invariant systems perspective. In this terminology, the extracted components are considered as outputs of a linear invariant system which corresponds to finite impulse response (FIR) filters. The number of filters is determined by the embedding dimension.We propose to explicitly define the frequency response of each filter responsible for the selection of informative components. We also introduce a subspace distance measure for clustering subspace models. We illustrate the methodology by analyzing lectroencephalograms (EEG).FCT - PhD scholarship (SFRH/BD/28404/2006)FCT - PhD scholarship (SFRH/BD/48775/2008

    When economic uncertainty disturbs fertility levels.

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    The idea that fertility reacts positively to economic prosperity and falls in times of crises is present in the literature on the evolution of fertility (e.g. Lee, 1990; Sobotka et al., 2011; Comolli, 2017). Periods of economic recession or stagnations are frequently followed by turn down moments on the number of births. Fertility tends to be pro-cyclical and reacts on the ups and downs of economic uncertainty, boosting the postponement and decreasing the quantum. Since 2010, Portugal has been harshly affected by the (1) economic crisis, (2) high unemployment rates and (3) negative consumer confidence index (CCI). Simultaneously, the country presented the lowest birth rates and fertility levels in the European Union since 2012 (Eurostat, 2015). Through an empirical approach, we explore the relationship between the number of childbirth, consumer confidence index, and unemployment rate by sex and for the 25 – 34 age group, within the period 2007-2017 (INE)

    Kinetic Ising System in an Oscillating External Field: Stochastic Resonance and Residence-Time Distributions

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    Experimental, analytical, and numerical results suggest that the mechanism by which a uniaxial single-domain ferromagnet switches after sudden field reversal depends on the field magnitude and the system size. Here we report new results on how these distinct decay mechanisms influence hysteresis in a two-dimensional nearest-neighbor kinetic Ising model. We present theoretical predictions supported by numerical simulations for the frequency dependence of the probability distributions for the hysteresis-loop area and the period-averaged magnetization, and for the residence-time distributions. The latter suggest evidence of stochastic resonance for small systems in moderately weak oscillating fields.Comment: Includes updated results for Fig.2 and minor text revisions to the abstract and text for clarit

    Linear Invariant Systems Theory for Signal Enhancement

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    This paper discusses a linear time invariant (LTI) systems approach to signal enhancement via projective subspace techniques. It provides closed form expressions for the frequency response of data adaptive finite impulse response eigenfilters. An illustrative example using speech enhancement is also presented.Este artigo apresenta a aplicação da teoria de sistemas lineares invariantes no tempo (LTI) na análise de técnicas de sub-espaço. A resposta em frequência dos filtros resultantes da decomposição em valores singulares é obtida aplicando as propriedades dos sistemas LTI

    Changes in the diet and body size of a small herbivorous mammal (hispid cotton rat, \u3ci\u3eSigmodon hispidus\u3c/i\u3e) following the late Pleistocene megafauna extinction

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    The catastrophic loss of large-bodied mammals during the terminal Pleistocene likely led to cascading effects within communities. While the extinction of the top consumers probably expanded the resources available to survivors of all body sizes, little work has focused on the responses of the smallest mammals. Here, we use a detailed fossil record from the southwestern United States to examine the response of the hispid cotton rat Sigmodon hispidus to biodiversity loss and climatic change over the late Quaternary. In particular, we focus on changes in diet and body size. We characterize diet through carbon (δ13C) and nitrogen (δ15N) isotope analysis of bone collagen in fossil jaws and body size through measurement of fossil teeth; the abundance of material allows us to examine population level responses at millennial scale for the past 16 ka. Sigmodon was not present at the cave during the full glacial, first appearing at ~16 ka after ice sheets were in retreat. It remained relatively rare until ~12 ka when warming tempera­tures allowed it to expand its species range northward. We find variation in both diet and body size of Sigmodon hispidus over time: the average body size of the population varied by ~20% (90–110 g) and mean δ13C and δ15N values ranged between −13.5 to −16.5‰ and 5.5 to 7.4‰ respectively. A state–space model suggested changes in mass were influenced by diet, maximum temperature and community structure, while the modest changes in diet were most influenced by community structure. Sigmodon maintained a fairly similar dietary niche over time despite contemporaneous changes in climate and herbivore community composition that followed the megafauna extinc­tion. Broadly, our results suggest that small mammals may be as sensitive to shifts in local biotic interactions within their ecosystem as they are to changes in climate and large-scale biodiversity loss

    Continuous partial trends and low-frequency oscillations of time series

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    International audienceThis paper presents a recent methodology developed for the analysis of the slow evolution of geophysical time series. The method is based on least-squares fitting of continuous line segments to the data, subject to flexible conditions, and is able to objectively locate the times of significant change in the series tendencies. The time distribution of these breakpoints may be an important set of parameters for the analysis of the long term evolution of some geophysical data, simplifying the intercomparison between datasets and offering a new way for the analysis of time varying spatially distributed data. Several application examples, using data that is important in the context of global warming studies, are presented and briefly discussed

    A bibliometric based analysis to identify promising domains of decarbonisation technologies

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    The high volume of research outputs related to technologies and strategies for decarbonisation can make it challenging to understand the relevance of the presented proposals. In this paper, a bibliometric-based analysis is proposed to understand better the domains and subdomains of decarbonisation technologies that have given more attention by the scientific community. The results show that carbon capture technologies, renewable energy sources, electric mobility, green hydrogen, and storage systems are the technology innovations that have received the most attention in the period 2013 to 2021. These results confirm the traditional supply-side orientation of research on technology innovations.info:eu-repo/semantics/acceptedVersio

    Hearing evaluation of Portuguese school communities: School-based Audiology versus Hearing Screening

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    Objectivo: Estudo da incidência da perda auditiva e de problemas otológicos em comunidades escolares do Norte do país de um total de 2550 participantes, entre os 3 e os 17 anos de idade. Desenho do Estudo: Levantamento estatístico nas próprias instituições de ensino sendo realizado um protocolo de avaliação auditiva de rastreio. Material e Métodos: A todos os participantes foi realizado o mesmo protocolo de avaliação que consistiu numa anamnese audiológica, otoscopia e exame audiométrico de rastreio, sendo considerado como critério de inclusão a autorização prévia por parte do encarregado de educação. Resultados: Foram identificados diversos problemas otológicos e a audiometria tonal de rastreio contabilizou limiares auditivos indicativos de hipoacusia, uni e bilateralmente, em cerca de 5,7% dos casos. Conclusões: O rastreio auditivo deve ser realizado o mais precocemente possível e fazer parte integral dos cuidados de saúde primários, de modo a orientar a criança para uma educação e acompanhamento apropriados.info:eu-repo/semantics/publishedVersio

    Chaotic hysteresis in an adiabatically oscillating double well

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    We consider the motion of a damped particle in a potential oscillating slowly between a simple and a double well. The system displays hysteresis effects which can be of periodic or chaotic type. We explain this behaviour by computing an analytic expression of a Poincar'e map.Comment: 4 pages RevTeX, 3 PS figs, uses psfig.sty. Submitted to Phys. Rev. Letters. PS file also available at http://dpwww.epfl.ch/instituts/ipt/berglund.htm
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