2,596 research outputs found
Correlations between structure and dynamics in complex networks
Previous efforts in complex networks research focused mainly on the
topological features of such networks, but now also encompass the dynamics. In
this Letter we discuss the relationship between structure and dynamics, with an
emphasis on identifying whether a topological hub, i.e. a node with high degree
or strength, is also a dynamical hub, i.e. a node with high activity. We employ
random walk dynamics and establish the necessary conditions for a network to be
topologically and dynamically fully correlated, with topological hubs that are
also highly active. Zipf's law is then shown to be a reflection of the match
between structure and dynamics in a fully correlated network, as well as a
consequence of the rich-get-richer evolution inherent in scale-free networks.
We also examine a number of real networks for correlations between topology and
dynamics and find that many of them are not fully correlated.Comment: 16 pages, 7 figures, 1 tabl
Identification of a fibrinogen-related protein (FBN9) gene in neotropical anopheline mosquitoes
<p>Abstract</p> <p>Background</p> <p>Malaria has a devastating impact on worldwide public health in many tropical areas. Studies on vector immunity are important for the overall understanding of the parasite-vector interaction and for the design of novel strategies to control malaria. A member of the fibrinogen-related protein family, <it>fbn9</it>, has been well studied in <it>Anopheles gambiae </it>and has been shown to be an important component of the mosquito immune system. However, little is known about this gene in neotropical anopheline species.</p> <p>Methods</p> <p>This article describes the identification and characterization of the <it>fbn9 </it>gene partial sequences from four species of neotropical anopheline primary and secondary vectors: <it>Anopheles darlingi, Anopheles nuneztovari, Anopheles aquasalis</it>, and <it>Anopheles albitarsis </it>(namely <it>Anopheles marajoara</it>). Degenerate primers were designed based on comparative analysis of publicly available <it>Aedes aegypti </it>and <it>An. gambiae </it>gene sequences and used to clone putative homologs in the neotropical species. Sequence comparisons and Bayesian phylogenetic analyses were then performed to better understand the molecular diversity of this gene in evolutionary distant anopheline species, belonging to different subgenera.</p> <p>Results</p> <p>Comparisons of the <it>fbn9 </it>gene sequences of the neotropical anophelines and their homologs in the <it>An. gambiae </it>complex (Gambiae complex) showed high conservation at the nucleotide and amino acid levels, although some sites show significant differentiation (non-synonymous substitutions). Furthermore, phylogenetic analysis of <it>fbn9 </it>nucleotide sequences showed that neotropical anophelines and African mosquitoes form two well-supported clades, mirroring their separation into two different subgenera.</p> <p>Conclusions</p> <p>The present work adds new insights into the conserved role of <it>fbn9 </it>in insect immunity in a broader range of anopheline species and reinforces the possibility of manipulating mosquito immunity to design novel pathogen control strategies.</p
Can the evolution of music be analyzed in a quantitative manner?
We propose a methodology to study music development by applying multivariate
statistics on composers characteristics. Seven representative composers were
considered in terms of eight main musical features. Grades were assigned to
each characteristic and their correlations were analyzed. A bootstrap method
was applied to simulate hundreds of artificial composers influenced by the
seven representatives chosen. Afterwards we quantify non-numeric relations like
dialectics, opposition and innovation. Composers differences on style and
technique were represented as geometrical distances in the feature space,
making it possible to quantify, for example, how much Bach and Stockhausen
differ from other composers or how much Beethoven influenced Brahms. In
addition, we compared the results with a prior investigation on philosophy.
Opposition, strong on philosophy, was not remarkable on music. Supporting an
observation already considered by music theorists, strong influences were
identified between composers by the quantification of dialectics, implying
inheritance and suggesting a stronger master-disciple evolution when compared
to the philosophy analysis.Comment: 8 pages, 6 figures, added references for sections 1 and 4.C, better
mathematical description on section 2. New values and interpretation, now
considering a bootstrap metho
Expression of methylthioadenosine phosphorylase (MTAP) in pilocytic astrocytomas
BACKGROUND/OBJECTIVES Pilocytic astrocytomas (PAs) are the most frequent astrocytomas in children and adolescents. Methilthioadenosine phosphorylase(MTAP) is a tumor-suppressor gene, the loss of expression of which is associated with a poor prognosis and better response to specific chemotherapy in leukemia and non-small-cell lung cancer. The expression of MTAP in brain tumors remains largely unknown and its biological role in PA is still unexplored. Our aims were to describe the immunohistochemical MTAP expression in a series of PAs and relate it to the clinicopathological features of the patients.
METHODS We assessed MTAP expression on immunohistochemistry in 69 pediatric and adult patients with PA in a tissue microarray platform. RESULTS Retained expression of MTAP was seen in >85% of the tumors compared to in the nonneoplastic adjacent tissue. Only 3 supratentorial tumors showed a complete loss of MTAP expression. No significant association with clinicopathological features or overall survival of the patients was found. CONCLUSIONS MTAP expression is retained in PAs and is not an outcome predictor for these tumors. Nevertheless, a subset of patients with PAs exhibiting a loss of MTAP could potentially benefit from treatment with specific chemotherapy, especially when lesions are recurrent or surgical resection is not recommended.This study was partially supported by the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (2012/19590-0) and an HCB program of financial support (Programa de Apoio e Incentivo a Pesquisa)
Reference Model in BPMN Notation for a Production Scheduling System
Companies are progressively investing in practices aimed at improving the quality of management, with the main purpose of enabling them to operate competitively in the present market. For this, it is necessary to document the activities and information of the existing business processes in the organization, aiming at reducing time and cost in the elaboration of the particular model. In this context, the objective of this work is to develop a reference model of the Production Scheduling (PS) processes, an important module of production planning and control (PPC). The research methodology used in this work was divided into the following stages: study of PS and business process modeling, definition of reference model processes, choice of methodology and process modeling tool, development of reference model and prototype of the software and, finally, analysis of results. The modeling notation used was the BPMN, since it is considered a standard language in the field of process modeling. The prototype was developed through the Delphi interface in order to apply the model to support the implementation of business management programs. As results, from a formal documentation, the model proved to be a useful mechanism in the understanding of the processes raised and appropriate in the support to the implantation of production management tools
Behavioral Finance: A Different View in the State of Rio de Janeiro
The objective of this work is to present the consolidation of foreign reflections of a new branch in the financial theory, behavioral finance, that it aims at to adhere to the psychological aspects and the sociological ones of the individuals in the process of taking of decision at the moment to carry through an investment, as well as its applications through the incorporation of evidences on the irrationality of the investor. This new segment has as objective the revision and the improvement of the economic-financial model used currently. Through this study it was verified presence of the effect of super valuation of the assets and the effect disposal, as well as of aversion to the risk, since in the occurred economic crisis in 2008 middle a bigger index in the closing of companies was evidenced, and a minor in the opening of companies in the state of Rio De Janeiro. The association to the behavioral finance in such a way provides the agreement of the psychological process that motivates the investments, assisting in the construction of a model of more adequate taking of decision, how much in the act of contract of its administrators who will have to possess abilities adequate psychological techniques and in intention to prevent cognitive bias as reliable excess. The regression for being static got errors in its forecast high thus was not an incisive method, being able to be applied the forecast of demand of products, not obtaining success thus in this model
Oil and Gas on the Brazilian Coast
The study of behavioral finance is characterized by analyzing the volatility of financial markets, however, in a contemporary view, one can also apply it in other fields such as commerce and factories, and its dislike to be able to invest or not its financial capital . The objective of this work is to present foreign reflections on a new branch in financial theory, Behavioral Finance, which aims to adhere the psychological and sociological aspects of the individuals in the decision making process at the time of making an investment, as well as their applications through incorporation evidence of the investor\u27s irrationality. This new segment aims to review and improve the current economic-financial model. The association with behavioral finances provides both the understanding of the psychological process that motivates the investments, helping in the construction of a more adequate decision-making model, and in the hiring of its managers who must possess adequate technical and psychological skills in order to avoid cognitive bias as overconfidence
Proposal of a Reference Model in BPMN Notation for an MRP System
Companies are progressively investing in practices aimed at improving the quality of management, with the main purpose of enabling them to operate competitively in the present market. For this, it is necessary to document the activities and information of the existing business processes in the organization, aiming at reducing time and cost in the elaboration of the particular model. In this context, the objective of this work is to develop a reference model of the Manufacturing Resource Planning (MRP) processes, an important module of production planning and control (PPC). The research methodology used in this work was divided into the following stages: study of MRP and business process modeling, definition of reference model processes, choice of methodology and process modeling tool, development of reference model and prototype of the software and, finally, analysis of results. The modeling notation used was the BPMN, since it is considered a standard language in the field of process modeling. The prototype was developed through the Delphi interface in order to apply the model to support the implementation of business management programs. As results, from a formal documentation, the model proved to be a useful mechanism in the understanding of the processes raised and appropriate in the support to the implantation of production management tools
Performance of Beef Heifers of Various Genetic Groups, Supplemented or Not, in Coastcross Pastures
The objective of this study was to determine whether the performance of beef heifers of different genetic groups was affected by breed x nutritional environment interactions. Sixty four weaned heifers, 16 per genetic group: ½ Angus + ½ Nellore (AN), ½ Canchim + ½ Nellore (CN), ½ Simmental + ½ Nellore (SN) and pure Nellore (NE), were used with or without 3.0 kg of concentrate.animal-1 .day-1 in a fertilized coastcross pasture under rotational grazing system. There were effects of genetic group and supplementation (P\u3c 0.05) on the weight and age at first estrus, but there was no interaction between them. In a rotational grazing system with 4000 kg of available dry matter per hectare with 13% of crude protein, the crossbred AN, supplemented or not, was more precocious (111 days) than Nellore heifers, showing the first estrus at 356 days of age and 324 kg of live weight
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