157 research outputs found
Investigating the topology of interacting networks - Theory and application to coupled climate subnetworks
Network theory provides various tools for investigating the structural or
functional topology of many complex systems found in nature, technology and
society. Nevertheless, it has recently been realised that a considerable number
of systems of interest should be treated, more appropriately, as interacting
networks or networks of networks. Here we introduce a novel graph-theoretical
framework for studying the interaction structure between subnetworks embedded
within a complex network of networks. This framework allows us to quantify the
structural role of single vertices or whole subnetworks with respect to the
interaction of a pair of subnetworks on local, mesoscopic and global
topological scales.
Climate networks have recently been shown to be a powerful tool for the
analysis of climatological data. Applying the general framework for studying
interacting networks, we introduce coupled climate subnetworks to represent and
investigate the topology of statistical relationships between the fields of
distinct climatological variables. Using coupled climate subnetworks to
investigate the terrestrial atmosphere's three-dimensional geopotential height
field uncovers known as well as interesting novel features of the atmosphere's
vertical stratification and general circulation. Specifically, the new measure
"cross-betweenness" identifies regions which are particularly important for
mediating vertical wind field interactions. The promising results obtained by
following the coupled climate subnetwork approach present a first step towards
an improved understanding of the Earth system and its complex interacting
components from a network perspective
Scarabaeoidea (Insecta : Coleoptera) in the Brazilian Cerrado : current state of knowledge
Besouros pertencentes Ă superfamĂlia Scarabaeoidea ocupam habitats variados, possuem hĂĄbitos alimentares diversifi cados, desempenham importante papel ecolĂłgico e diversas espĂ©cies apresentam importĂąncia agrĂcola. No entanto, estudos com esse grupo na regiĂŁo do Cerrado sĂŁo escassos. Nesta revisĂŁo realizou-se um levantamento dos artigos publicados nos Ășltimos 30 anos a respeito dos Scarabaeoidea no Cerrado. Foram recuperados 64 artigos, realizados em nove unidades da federação, que focavam quatro temas principais espĂ©cies praga, aspectos bioecolĂłgicos, biodiversidade e importĂąncia ecolĂłgica, e tĂ©cnicas e metodologias de coleta de Scarabaeoidea. Os resultados desta revisĂŁo indicam que poucos estudos foram realizados com os Scarabaeoidea no Cerrado brasileiro nas Ășltimas dĂ©cadas frente Ă importĂąncia e diversidade desse grupo de insetos.Beetles belonging to the superfamily Scarabaeoidea occupy different habitats, present feeding habits diversifi ed, play an important ecological role and several species have agricultural importance. However, studies with this group in the Brazilian Cerrado are scarce. In this review we carried out a survey of scientifi c articles published in the past 30 years concerning Scarabaeoidea in the Cerrado. Were found 64 studies in nine Brazilian states. The studies focused on four main topics: pest species, bioecology, biodiversity and ecological importance, techniques and methodologies for collecting Scarabaeoidea. The results of this review indicate that few studies have been conducted with Scarabaeoidea in the Cerrado in recent decades compared to the importance and diversity of this group of insects
Harnessing content and context for enhanced decision making
In a time in which a significant amount of interpersonal interactions
take place online, one must enquire to which extent are these
milieus suitable for supporting the complexity of our communication.
This is especially important in more sensitive domains, such as the one of
Online Dispute Resolution, in which inefficient communication environments
may result in misunderstandings, poor decisions or the escalation
of the conflict. The conflict manager, in particular, may find his skills
severely diminished, namely in what concerns the accurate perception of
the state of the parties. In this paper the development of a rich communication
framework is detailed that conveys contextual information about
their users, harnessed from the transparent analysis of their behaviour
while communicating. Using it, the conflict manager may not only better
perceive the conflict and how it affects each party but also take better
contextualized decisions, closer to the ones taken in face-to-face settings.This work is part-funded by ERDF - European Regional Development Fund
through the COMPETE Programme (operational programme for competitiveness)
and by National Funds through the FCT { Fundação para a CiĂȘncia e a
Tecnologia (Portuguese Foundation for Science and Technology) within project
FCOMP-01-0124-FEDER-028980 (PTDC/EEI-SII/1386/2012) and project PEst-
OE/EEI/UI0752/2014
Response of vegetation to fire disturbance: short-term dynamics in two savanna physiognomies
Fire is a constitutive ecological force in savanna ecosystems, but few studies have monitored its short-term effects on plant community dynamics. This study investigated changes in plant diversity in the South American savanna (Cerrado) after severe disturbance by fire. We monitored 30 permanent plots (10 m Ă 5 m) distributed in two Cerrado physiognomies (tĂpico: more forested; ralo: grass-dominated), being 10 plots in the area disturbed by fire, and five in a preserved control area (undisturbed). From August 2010 to June 2011, we evaluated changes in species richness, abundance and composition of savanna vegetation. Monitoring started one week after the fire; disturbed plots were surveyed monthly, while control plots were surveyed every two months. We observed rapid reassembling in both physiognomies: plots affected by fire showed rapid increase in species richness and plant density during the first four months after the disturbance. Concerning species composition, disturbed plots in the cerrado tĂpico tended to converge to control plots after one year, but each local assemblage followed particular temporal trajectories. A different pattern characterized cerrado ralo plots, which showed heterogeneous trajectories and lack of convergence between disturbed and control plots; the structure of these assemblages will likely change in next years. In conclusion, our results showed that fire significantly affected plant diversity in the two savanna physiognomies (cerrado tĂpico and ralo), but also indicated that community reassembling is fast, with different dynamics between Cerrado physiognomies
Deconfining Phase Transition as a Matrix Model of Renormalized Polyakov Loops
We discuss how to extract renormalized from bare Polyakov loops in SU(N)
lattice gauge theories at nonzero temperature in four spacetime dimensions.
Single loops in an irreducible representation are multiplicatively renormalized
without mixing, through a renormalization constant which depends upon both
representation and temperature. The values of renormalized loops in the four
lowest representations of SU(3) were measured numerically on small, coarse
lattices. We find that in magnitude, condensates for the sextet and octet loops
are approximately the square of the triplet loop. This agrees with a large
expansion, where factorization implies that the expectation values of loops in
adjoint and higher representations are just powers of fundamental and
anti-fundamental loops. For three colors, numerically the corrections to the
large relations are greatest for the sextet loop, ; these
represent corrections of for N=3. The values of the renormalized
triplet loop can be described by an SU(3) matrix model, with an effective
action dominated by the triplet loop. In several ways, the deconfining phase
transition for N=3 appears to be like that in the matrix model of
Gross and Witten.Comment: 24 pages, 7 figures; v2, 27 pages, 12 figures, extended discussion
for clarity, results unchange
Estudos sobre a nutrição mineral do arroz: XIV. efeitos dos excessos de Al, Cl e Mn nas variedades IAC-25 e IAC-47
Rice plants were grown either in full strength nÂș 2 solution of HOAGLAND & ARNON (1950) or in the same with high levels of Al, Cl and Mn (25, 1750 and 25 ppm, respectively). Plants with excess of each element did not complete the reproductive phase of development. Symptoms of toxicity appeared in response to the high levels supplied in the substrate. Dry matter production was relatively more affected in the case of the variety IAC-47. On the other hand, both varieties were more sensitive to Mn toxicity than to Al excess. The leaves had the following levels of the elements under the respective treatments, respectively for the variety IAC-25 and for the variety IAC-47; Al-107 and 221 ppm; Cl-87,500 and 17,500 (lower and upper leaves), 44,125 and 16,250 (lower and upper leaves); Mn - 1,670 and 1,769. The Al content of the roots was 5,639 and 5,872 ppm. Al toxicity decreased P content in all plant parts.Plantas de arroz, variedades IAC-25 e IAC-47 foram cultivadas em solução nutritiva completa e com excesso de Al, Cl e Mn (25, 1750 e 25 ppm, respectivamente). As Ășltimas nĂŁo completaram o ciclo. Foram observados sintomas tĂpicos de toxidez. A produção de matĂ©ria seca foi mais afetada pelos tratamentos na variedade IAC-47. Ambas as variedades mostraram-se mais sensĂveis a toxidez de Mn que Ă de Al. Foram determinados os teores foliares de Al, Cl e Mn associados Ă toxidez correspondente
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