A novel evolutionary formulation of the maximum independent set problem

We introduce a novel evolutionary formulation of the problem of finding a maximum independent set of a graph. The new formulation is based on the relationship that exists between a graph's independence number and its acyclic orientations. It views such orientations as individuals and evolves them with the aid of evolutionary operators that are very heavily based on the structure of the graph and its acyclic orientations. The resulting heuristic has been tested on some of the Second DIMACS Implementation Challenge benchmark graphs, and has been found to be competitive when compared to several of the other heuristics that have also been tested on those graphs

On Higher Derivatives as Constraints in Field Theory: a Geometric Perspective

We formalize geometrically the idea that the (de Donder) Hamiltonian formulation of a higher derivative Lagrangian field theory can be constructed understanding the latter as a first derivative theory subjected to constraints.Comment: 7 page

Especiação em solos: aspectos gerais.

Considerações sobre a especiação aplicada a solos.bitstream/CNPS/11580/1/doc47_2003_especiacao_solos.pd

Solução do solo: importância e extração por centrifugação.

Considerações sobre estudos de técnicas de extração da fase aquosa do solo

Synthesis of a Plant-based Dust Suppressant and Testing on Coal from Moatize, Mozambique

The dust suppressant was synthesized using Pinus elliottii resin as raw material for the new plant-based formulation. The dust suppressant formulation was prepared by solubilizing rosin in a ternary solution containing calcium chloride, ultrapure water, and ethanol in a molar ratio of 1:2:8. After centrifugation the supernatant was collected, 20 mL of 2 % γ-polyglutamic acid dissolved in an aqueous ethanol solution was added, and the mixture was stirred for 2 hours. The dust suppressant formulation included Pinus extract and γ-PGA acid, resulting in a plant-based dust suppressant. The performance of the new formulation in reducing PM10 was significantly superior (82.7 %) to that of water. This suppressant is suitable for spraying onto coal ore piles and hopper cars carrying coal ore. The wettability of the product was analyzed by the Walker test, which confirmed its adhesiveness to coal dust. This work is licensed under a Creative Commons Attribution 4.0 International License

HIV-1 mother-to-child transmission in Brazil (1994\u20132016): a time series modeling

HIV-1 mother-to-child transmission (HIV-1 MTCT), is an important cause of children mortality worldwide. Brazil has been traditionally praised by its HIV/Aids program, which provides free-of-charge care for people living with HIV-1. Using public epidemiology and demographic databases, we aimed at modeling HIV-1 MTCT prevalence in Brazil through the years (1994\u20132016) and elaborate a statistical model for forecasting, contributing to HIV-1 epidemiologic surveillance and healthcare decision-making. We downloaded sets of live births and mothers\u2019 data alongside HIV-1 cases notification in children one year old or less. Through time series modeling, we estimated prevalence along the years in Brazil, and observed a remarkable decrease of HIV-1 MTCT between 1994 (10 cases per 100,000 live births) and 2016 (five cases per 100,000 live births), a reduction of 50%. Using our model, we elaborated a prognosis for each Brazilian state to help HIV-1 surveillance decision making, indicating which states are in theory in risk of experiencing a rise in HIV-1 MTCT prevalence. Ten states had good (37%), nine had mild (33%), and eight had poor prognostics (30%). Stratifying the prognostics by Brazilian region, we observed that the Northeast region had more states with poor prognosis, followed by North and Midwest, Southeast and South with one state of poor prognosis each. Brazil undoubtedly advanced in the fight against HIV-1 MTCT in the past two decades. We hope our model will help indicating where HIV-1 MTCT prevalence may rise in the future and support government decision makers regarding HIV-1 surveillance and prevention

Magnetic Brane-worlds

We investigate brane-worlds with a pure magnetic field and a perfect fluid. We extend earlier work to brane-worlds, and find new properties of the Bianchi type I brane-world. We find new asymptotic behaviours on approach to the singularity and classify the critical points of the dynamical phase space. It is known that the Einstein equations for the magnetic Bianchi type I models are in general oscillatory and are believed to be chaotic, but in the brane-world model this chaotic behaviour does not seem to be possible.Comment: 21 pages, 3 ps figures; To appear in CQ

University transformation and quantification devices

Indexación: Scopus; Scielo.Las políticas de Educación Superior en Chile les demandan a las Universidades la instalación de dispositivos de gestión orientados a organizar, cuantificar y monitorear el trabajo académico. Pensando en las implicaciones del uso de estos dispositivos de gestión, este trabajo presenta los resultados de un análisis discursivo de 95 documentos de trabajo (Reglamentos, Bases de concurso, Formularios de acreditación) para conocer las interpelaciones que realiza a la labor universitaria. Mediante el método de análisis de discurso, se caracteriza la actuación de los documentos oficiales que regulan y transforman el trabajo académico. El estudio realizado evidencia que los dispositivos de gestión del Trabajo académico performan el trabajo mediante acciones tales como: establecer jerarquías entre las múltiples tareas de un académico y entre académicos, mediante criterios que no han sido discutidos por la comunidad profesional; objetivar procesos laborales y asumir consensos en torno a ello, desconociendo disputas y desacuerdos actuales; omitir el contexto de producción académica, construyendo una imagen del trabajo como proceso individual; y finalmente instando relaciones laborales individualizadas y competitivas.In Chile, higher education policies have required universities to adopt management tools related to the monitoring and quantification of academic work. Accordingly, this paper presents the results of a documentary study of 95 official documents concerning academic work (Regulations, Scholarship and Grant Application Guidelines and Accreditation Application Forms) in order to understand the regulations pertaining to academic work. Discourse analysis was used to determine how these documents are used in the university environment to regulate and transform the academic work. The present study shows that management tools adopted characterize the academic work through actions such as: establish hierarchies among the multiple tasks of a faculty member and among faculty members using criteria that have not been discussed by the academic community; objectify work processes and reach consensus over them, disregarding current disputes and disagreements; omit the context of academic production creating an image of work as an individual process; and finally urge the establishment of individualizing and competitive work relationships.http://ref.scielo.org/d2c4s

Reduction of quantum noise in optical interferometers using squeezed light

We study the photon counting noise in optical interferometers used for gravitational wave detection. In order to reduce quantum noise a squeezed vacuum state is injected into the usually unused input port. Here, we specifically investigate the so called `dark port case', when the beam splitter is oriented close to 90{\deg} to the incoming laser beam, such that nearly all photons go to one output port of the interferometer, and only a small fraction of photons is seen in the other port (`dark port'). For this case it had been suggested that signal amplification is possible without concurrent noise amplification [R.Barak and Y.Ben-Aryeh, J.Opt.Soc.Am.B25(361)2008]. We show that by injection of a squeezed vacuum state into the second input port, counting noise is reduced for large values of the squeezing factor, however the signal is not amplified. Signal strength only depends on the intensity of the laser beam.Comment: 8 pages, 1 figur