1,632 research outputs found

    Human Mobility in Large Cities as a Proxy for Crime

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    We investigate at the subscale of the neighborhoods of a highly populated city the incidence of property crimes in terms of both the resident and the floating population. Our results show that a relevant allometric relation could only be observed between property crimes and floating population. More precisely, the evidence of a superlinear behavior indicates that a disproportional number of property crimes occurs in regions where an increased flow of people takes place in the city. For comparison, we also found that the number of crimes of peace disturbance only correlates well, and in a superlinear fashion too, with the resident population. Our study raises the interesting possibility that the superlinearity observed in previous studies [Bettencourt et al., Proc. Natl. Acad. Sci. USA 104, 7301 (2007) and Melo et al., Sci. Rep. 4, 6239 (2014)] for homicides versus population at the city scale could have its origin in the fact that the floating population, and not the resident one, should be taken as the relevant variable determining the intrinsic microdynamical behavior of the system.Comment: 17 pages, 8 Figure

    Unintended multispecies co-benefits of an Amazonian community-based conservation programme

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    Urgent challenges posed by widespread degradation in tropical ecosystems with poor governance require new development pathways to reconcile biodiversity conservation and human welfare. Community-based conservation management has shown potential for integrating socio-economic needs with conservation goals in tropical environments; however, assessing the effectiveness of this approach is often held back by the lack of comprehensive ecological assessments. We conduct a robust ecological evaluation of the largest community-based conservation management initiative in the Brazilian Amazon over the last 40 years. We show that this programme has induced large-scale population recovery of the target giant South American turtle (Podocnemis expansa) and other freshwater turtles along a 1,500-km section of a major tributary of the Amazon River. Poaching activity on protected beaches was around 2% compared to 99% on unprotected beaches. We also find positive demographic co-benefits across a wide range of non-target vertebrate and invertebrate taxa. As a result, beaches protected by local communities represent islands of high biodiversity, while unprotected beaches remain ‘empty and silent’, showing the effectiveness of empowering local conservation action, particularly in countries experiencing shortages in financial and human resources

    Allocation of control resources for machine-to-machine and human-to-human communications over LTE/LTE-A networks

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    The Internet of Things (IoT) paradigm stands for virtually interconnected objects that are identifiable and equipped with sensing, computing, and communication capabilities. Services and applications over the IoT architecture can take benefit of the long-term evolution (LTE)/LTE-Advanced (LTE-A), cellular networks to support machine-type communication (MTC). Moreover, it is paramount that MTC do not affect the services provided for traditional human-type communication (HTC). Although previous studies have evaluated the impact of the number of MTC devices on the quality of service (QoS) provided to HTC users, none have considered the joint effect of allocation of control resources and the LTE random-access (RA) procedure. In this paper, a novel scheme for resource allocation on the packet downlink (DL) control channel (PDCCH) is introduced. This scheme allows PDCCH scheduling algorithms to consider the resources consumed by the random-access procedure on both control and data channels when prioritizing control messages. Three PDCCH scheduling algorithms considering RA-related control messages are proposed. Moreover, the impact of MTC devices on QoS provisioning to HTC traffic is evaluated. Results derived via simulation show that the proposed PDCCH scheduling algorithms can improve the QoS provisioning and that MTC can strongly impact on QoS provisioning for real-time traffic.The Internet of Things (IoT) paradigm stands for virtually interconnected objects that are identifiable and equipped with sensing, computing, and communication capabilities. Services and applications over the IoT architecture can take benefit of the long-33366377CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informaçãosem informaçã

    The angular scale of homogeneity with SDSS-IV DR16 Luminous Red Galaxies

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    We report measurements of the angular scale of cosmic homogeneity (θH\theta_{H}) using the recently released luminous red galaxy sample of the sixteenth data release of the Sloan Digital Sky Survey (SDSS-IV LRG DR16). It consists of a model-independent method, as we only use the celestial coordinates of these objects to carry out such an analysis. The observational data is divided into thin redshift bins, namely 0.67<z<0.680.67<z<0.68, 0.70<z<0.710.70<z<0.71, and 0.73<z<0.740.73<z<0.74, in order to avoid projection biases, and we estimate our uncertainties through a bootstrap method and a suite of mock catalogues. We find that the LRGs exhibit an angular scale of homogeneity consistent with the predictions of the standard cosmology within the redshift interval studied. Considering the bootstrap method, in which the measurements are obtained in a model-independent way, we found at 1σ\sigma level that θHboot(0.675)=7.57¹2.91\theta_H^{boot}(0.675) = 7.57 \pm 2.91 deg, θHboot(0.705)=7.49¹2.63\theta_H^{boot} (0.705) = 7.49 \pm 2.63 deg and θHboot(0.735)=8.88¹2.81\theta_H^{boot} (0.735) = 8.88 \pm 2.81 deg. Such results are in good agreement with the ones obtained using mock catalogues built under the assumption of the standard cosmological model.Comment: 13 pages, 4 figures, 3 tables. References updated; matches version published in JCA

    Can the angular scale of cosmic homogeneity be used as a cosmological test?

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    In standard cosmology, the cosmic homogeneity scale is the transition scale above which the patterns arising from non-uniformities -- such as groups and clusters of galaxies, voids, and filaments -- become indistinguishable from a random distribution of sources. Recently, different groups have investigated the feasibility of using such a scale as a cosmological test and arrived at different conclusions. In this paper, we complement and extend these studies by exploring the evolution of the spatial (RH{\cal{R}}_H) and angular (θH\theta_H) homogeneity scales with redshift, assuming a spatially flat, Λ\Lambda-Cold Dark Matter %(Λ\LambdaCDM) universe and linear cosmological perturbation theory. We confirm previous results concerning the non-monotonicity of RH{\cal{R}}_H with the matter density parameter Ωm0\Omega_{m0} but also show that it exhibits a monotonical behavior with the Hubble constant H0H_0 within a large redshift interval. More importantly, we find that, for z≳0.6z \gtrsim 0.6, the angular homogeneity scale not only presents a monotonical behavior with Ωm0\Omega_{m0} and H0H_0 but is quite sensitive to H0H_0, especially at higher redshifts. These results, therefore, raise the possibility of using θH\theta_H as a new, model-independent way to constrain cosmological parameters.Comment: 10 pages, 24 figure

    Hybrid Model Based on Genetic Algorithms and SVM Applied to Variable Selection Within Fruit Juice Classification

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    Research article[Abstract] Given the background of the use of Neural Networks in problems of apple juice classification, this paper aim at implementing a newly developed method in the field of machine learning: the Support Vector Machines (SVM). Therefore, a hybrid model that combines genetic algorithms and support vector machines is suggested in such a way that, when using SVM as a fitness function of the Genetic Algorithm (GA), the most representative variables for a specific classification problem can be selected

    Relevance of the Carotid Body Chemoreflex in the Progression of Heart Failure.

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    Chronic heart failure (CHF) is a global health problem affecting millions of people. Autonomic dysfunction and disordered breathing patterns are commonly observed in patients with CHF, and both are strongly related to poor prognosis and high mortality risk. Tonic activation of carotid body (CB) chemoreceptors contributes to sympathoexcitation and disordered breathing patterns in experimental models of CHF. Recent studies show that ablation of the CB chemoreceptors improves autonomic function and breathing control in CHF and improves survival. These exciting findings indicate that alterations in CB function are critical to the progression of CHF. Therefore, better understanding of the physiology of the CB chemoreflex in CHF could lead to improvements in current treatments and clinical management of patients with CHF characterized by high chemosensitivity. Accordingly, the main focus of this brief review is to summarize current knowledge of CB chemoreflex function in different experimental models of CHF and to comment on their potential translation to treatment of human CHF
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