1,632 research outputs found
Human Mobility in Large Cities as a Proxy for Crime
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
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 40âyears. 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 âempty and silentâ, 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
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 - COORDENAĂĂO DE APERFEIĂOAMENTO DE PESSOAL DE NĂVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTĂFICO E TECNOLĂGICOsem informaçãosem informaçã
The angular scale of homogeneity with SDSS-IV DR16 Luminous Red Galaxies
We report measurements of the angular scale of cosmic homogeneity
() 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 , ,
and , 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 1 level that deg, deg and
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?
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 () and angular ()
homogeneity scales with redshift, assuming a spatially flat, -Cold
Dark Matter %(CDM) universe and linear cosmological perturbation
theory. We confirm previous results concerning the non-monotonicity of
with the matter density parameter but also show
that it exhibits a monotonical behavior with the Hubble constant within a
large redshift interval. More importantly, we find that, for ,
the angular homogeneity scale not only presents a monotonical behavior with
and but is quite sensitive to , especially at higher
redshifts. These results, therefore, raise the possibility of using
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
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.
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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