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The Central University of Chile is the first autonomous private university in Chile, founded in 1982 in Santiago de Chile. It's accredited in the areas of institutional management and undergraduate teaching by the National Accreditation Commission of Chile for a term of four years from December 2008 to December 2012.The Central University of Chile is structured in nine faculties, in which are held 2 Ph.D. programs, 23 master's programs, 29 undergraduate programs, 6 top-level technical programs and various training programs and continuing education in the areas of Management, Architecture, Social science, Law, Education, Health and Technology.The Headquarters of Central University of Chile is located in the University District of Santiago, near the Toesca metro station, addition to four campuses, an extension center and a sports center in the heart of the capital, totaling more than 80,000 m² infraestructura. Also has two campus in the cities of Antofagasta and La Serena in the north of Chile.In 2010 the Central University of Chile established the country's first community college, with support from LaGuardia Community College of the City University of New York Wikipedia.


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Finis Terrae University | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 8 more authors.
Advances in Intelligent Systems and Computing | Year: 2015

In this paper, we propose a set of Modified Binary Firefly Algorithms (MBFF) to solve different instances of the Set Covering Problem (SCP). The algorithms consider eight Transfer Functions and five Discretization Methods in order to solve the binary representation of SCP. The results obtained show that our algorithms are a good and cheap alternative to solve the problem at hand. © Springer International Publishing Switzerland 2015. Source


Whitman C.J.,Central University of Chile
Key Engineering Materials | Year: 2014

According to the latest official census of 2002, earth construction represented 5.5% of the Chilean building stock. These buildings of traditional construction techniques of unfired earth and straw blocks (adobe), rammed earth (tapial) or wattle and daub (quincha) form a large proportion of Chile's National Monuments and heritage buildings. In addition to their heritage value, these buildings with their high thermal mass, respond well to the climate conditions of both the altiplano of northern Chile and the Central Valley, zones with high diurnal temperature oscillations, with typical daily temperature differences of up to 20°C. However following the 2005 earthquake in Tarapacá, northern Chile and that of the 27th February 2010 in Central Chile a serious rethink has been required as to the retention and restoration of adobe buildings. Public opinion has labelled earth construction as unsafe and most reconstruction to date has taken place with prefabricated timber solutions which lack the necessary thermal mass to respond well to the climatic conditions. At the same time research into the structural integrity, seismic resistance, maintenance and the living conditions provided by earth construction has been undertaken. In this wider context this paper presents the compilation of international and Chilean research into the hygrothermal properties of adobe construction, in addition to the authors insitu measurements of the temperature and relative humidity in two surviving adobe dwellings in the earthquake hit village of Chépica located in Chilés Central valley. These measurements are compared with those of a dwelling rebuilt with straw bales and earth render in the same location. Based on this information the paper studies the challenge of rebuilding and restoring heritage buildings whilst providing occupants with the necessary levels of environmental comfort. © (2014) Trans Tech Publications, Switzerland. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Finis Terrae University | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Advances in Intelligent Systems and Computing | Year: 2015

The Set Covering Problem (SCP) is a well-known NP hard discrete optimization problem that has been applied to a wide range of industrial applications, including those involving scheduling, production planning and location problems. The main difficulties when solving the SCP with a metaheuristic approach are the solution infeasibility and set redundancy. In this paper we evaluate a state of the art new formulation of the SCP which eliminates the need to address the infeasibility and set redundancy issues. The experimental results, conducted on a portfolio of SCPs from the Beasley’s OR-Library, show the gains obtained when using a new formulation to solve the SCP using the ACO metaheuristic. © Springer International Publishing Switzerland 2015. Source


Ruiz-Gonzalez I.,Complutense University of Madrid | Sanchez M.A.,Complutense University of Madrid | Garcia-Fernandez R.A.,Complutense University of Madrid | Garcia-Palencia P.,Complutense University of Madrid | And 3 more authors.
Reproduction in Domestic Animals | Year: 2012

Contents: The objective of this study was to investigate differences on the endometrial immunoexpression of type I IFN receptor subunit 1 (IFNAR1) and oxytocin receptor (OTR) during the time of maternal recognition of pregnancy in sheep, when oestrus is synchronized with either prostaglandin analogues (group PG) or conventional progestagens (group P). Plasma progesterone was measured from day 0 to 21 post-coitus (pc) (day0=day of oestrus). Immunohistochemistry was performed in samples of uterine horns from pregnant sheep on days 9pc, 13pc, 15pc, 17pc and 21pc to locate IFNAR1 and OTR expression in different endometrial compartments. Mean levels of plasma progesterone were different between treatments, obtaining higher levels in the PG group than in the P group (p<0.05). Comparing days of pregnancy, IFNAR1 protein expression was different in the luminal epithelium (LE) (p<0.05), while OTR was different in the LE and in the superficial glandular epithelium (SG) (p<0.05). Temporal variation on the expression of both proteins from day 9pc to 21pc has been evidenced. IFNAR1 and OTR expression did not show significant differences between treatments. However, the response observed in the endometrium was highly inconsistent when prostaglandin analogues were used. Therefore, the protocol based on prostaglandin analogues still needs to be optimized before being considered as a better alternative to progestagens for oestrous synchronization in sheep. © 2011 Blackwell Verlag GmbH. Source


Moraga L.,Central University of Chile | Arenas C.,Synopsys Inc. | Henriquez R.,Federico Santa Maria Technical University | Bravo S.,Federico Santa Maria Technical University | Solis B.,Argelander Institute For Astronomie
Physica B: Condensed Matter | Year: 2016

We calculate the electrical conductivity of polycrystalline metallic films by means of a semi-numerical procedure that provides solutions of the Boltzmann transport equation, that are essentially exact, by summing over classical trajectories according to Chambers’ method. Following Mayadas and Shatzkes (MS), grain boundaries are modeled as an array of parallel plane barriers situated perpendicularly to the direction of the current. Alternatively, according to Szczyrbowski and Schmalzbauer (SS), the model consists in a triple array of these barriers in mutual perpendicular directions. The effects of surface roughness are described by means of Fuchs’ specularity parameters. Following SS, the scattering properties of grain boundaries are taken into account by means of another specularity parameter and a probability of coherent passage. The difference between the sum of these and one is the probability of diffuse scattering. When this formalism is compared with the approximate formula of Mayadas and Shatzkes (Phys. Rev. B 1, 103 (1986)) it is shown that the latter greatly overestimates the film resistivity over most values of the reflectivity of the grain boundaries. The dependence of the conductivity of thin films on the probability of coherent passage and grain diameters is examined. In accordance with MS we find that the effects of disorder in the distribution of grain diameters is quite small. Moreover, we find that it is not safe to neglect the effects of the scattering by the additional interfaces created by stacked grains. However, when compared with recent resitivity-thickness data, it is shown that all three formalisms can provide accurate fits to experiment. In addition, it is shown that, depending on the respective reflectivities and distance from a surface, some of these interfaces may increase or diminish considerably the conductivity of the sample. As an illustration of this effect, we show a tentative fit of resistivity data of gold films measured by Chen et al. (Appl. Phys. 60, 659 (2005)). Finally, we present a new version of Matthiessen's rule that describe, with high accuracy, the way in which the contributions from surface scattering and grain boundary combine to form the total resistivity of the sample. © 2016 Elsevier B.V. Source


Tojo M.,Osaka Prefecture University | Van West P.,University of Aberdeen | Hoshino T.,Japan National Institute of Advanced Industrial Science and Technology | Kida K.,Osaka Prefecture University | And 12 more authors.
Fungal Biology | Year: 2012

Pythium polare sp. nov. is a new heterothallic oomycete species isolated from fresh water and moss from various locations in both the Arctic and Antarctic. This water mould is able to infect stems and leaves of Sanionia moss (Sanionia uncinata). Pythium polare causes brown discolouration in in vitro inoculation tests at 5 °C after 5 weeks of inoculation. It is characterized by globose sporangia with various lengths of discharge tubes releasing zoospores and aplerotic oospores with usually one to five antheridia. The sexual structures are only produced in a dual culture of antheridial and oogonial isolates. Phylogenetic analysis, based on ITS sequencing, places all isolated strains of P. polare in a unique new clade, hence it is considered a novel species. Pythium canariense and Pythium violae are the most closely related species of P. polare based both on morphology and the phylogenetic analysis. © 2012 The British Mycological Society. Source


Niklander S.,Adolfo Ibanez University | Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | And 4 more authors.
Communications in Computer and Information Science | Year: 2016

This paper focuses on the analysis of celebrity representations through Instagram. We refer to representation of a person as the set of concepts, images, ideas and emotions that this person transmit to the world. Representations transmit useful information for fans, but also for the entities related with the involved person. However, the representation exposed by posted images is hard to automatically process as depend on several variables which are complex to interpret. We propose then to employ discourse analysis in order to facilitate the analysis of such people representations. Discourse analysis is a qualitative and interpretive methodology for analyzing social phenomena through any communication mechanism. We illustrate interesting results where the use of discourse analysis allows us to easily process representations through images. © Springer International Publishing Switzerland 2016. Source


Niklander S.,Adolfo Ibanez University | Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | And 4 more authors.
Communications in Computer and Information Science | Year: 2016

Today, once a political corruption case takes place, it is rapidly viralized along the Internet where people can react by posting their opinions through social networks. Such audience reaction is clearly interesting but complex to analyze as people employs stereotypes, metaphors, and ironies expressed in an informal language hard to interpret. In this paper, we present how content analysis can help us to uncover the hidden meaning of a message. We focus here on the automated analysis of two political corruption cases and its corresponding opinions through social networks. In particular, one case involves the current government while the second one mostly involves the opposite side. Interesting results are gathered where the use of Content Analysis allows us to easily process the social network information in order to provide clear feedback. © Springer International Publishing Switzerland 2016. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
IEEE International Conference on Adaptive Science and Technology, ICAST | Year: 2015

The Sudoku puzzle consists in filling a square matrix with 9 rows and 9 columns, divided into 9 3×3 regions, so that each column, row, and region contains different digits from 1 to 9. Such a puzzle belongs to the NP-complete class of problems, existing different exact and approximate methods able to solve it. This paper reports recent results for solving Sudokus achieved by combining metaheuristics and a filtering technique coming from the constraint programming domain named AC3. © 2014 IEEE. Source


Arenas C.,University of Chile | Arenas C.,Synopsys Inc. | Henriquez R.,Federico Santa Maria Technical University | Moraga L.,Central University of Chile | And 2 more authors.
Applied Surface Science | Year: 2015

We calculate the electrical resistivity of a metallic specimen, under the combined effects of electron scattering by impurities, grain boundaries, and rough surfaces limiting the film, using a quantum theory based upon the Kubo formalism. Grain boundaries are represented by a one-dimensional periodic array of Dirac delta functions separated by a distance "d" giving rise to a Kronig-Penney (KP) potential. We use the Green's function built from the wave functions that are solutions of this KP potential; disorder is included by incorporating into the theory the probability that an electron is transmitted through several successive grain boundaries. We apply this new theory to analyze the resistivity of samples S1, S2, S7 and S8 measured between 4 and 300 K reported in Appl. Surf. Science 273, 315 (2013). Although both the classical and the quantum theories predict a resistivity that agrees with experimental data to within a few percent or better, the phenomena giving rise to the increase of resistivity over the bulk are remarkably different. Classically, each grain boundary contributes to the electrical resistance by reflecting a certain fraction of the incoming electrons. In the quantum description, there are states (in the allowed KP bands) that transmit electrons unhindered, without reflections, while the electrons in the forbidden KP bands are localized. A distinctive feature of the quantum theory is that it provides a description of the temperature dependence of the resistivity where the contribution to the resistivity originating on electron-grain boundary scattering can be identified by a certain unique grain boundary reflectivity R, and the resistivity arising from electron-impurity scattering can be identified by a certain unique ℓIMP mean free path attributable to impurity scattering. This is in contrast to the classical theory of Mayadas and Shatzkes (MS), that does not discriminate properly between a resistivity arising from electron-grain boundary scattering and that arising from electron-impurity scattering, for MS theory does not allow parameters (ℓIMP, R) to be uniquely adjusted to describe the temperature dependence of the resistivity data. The same data can be described using different sets of (R, ℓIMP); the latter parameter can be varied by two orders of magnitude in the case of small grained samples d < ℓ, and by a factor of 4 in the case of samples made out of large grains d > ℓ (where ℓ is the bulk mean free path at 300 K). For samples d > ℓ, the increase of resistivity is attributed not to electrons being partially reflected by the grain boundaries, but to a decrease in the number of states at the Fermi sphere that are allowed bands of the KP potential; hence the reflectivity required by the quantum model turns out to be an order of magnitude smaller than that required by the classical MS theory. For samples d < ℓ, the resistivity increase originates mainly from Anderson localization induced by electron grain boundary scattering from disordered successive grains characterized by a localization length of the order of 110 nm and not from electrons being partially reflected by grain boundaries; the outcome is that the reflectivity required by the quantum theory turns out to be about 4 times smaller than that required by the classical MS theory. © 2015 Elsevier B.V. All rights reserved. Source


Cruz-Montecinos C.,University of Chile | Cruz-Montecinos C.,Laboratory of Biomechanics | Gonzalez Blanche A.,Laboratory of Biomechanics | Lopez Sanchez D.,Central University of Chile | And 4 more authors.
Journal of Anatomy | Year: 2015

Different authors have modelled myofascial tissue connectivity over a distance using cadaveric models, but in vivo models are scarce. The aim of this study was to evaluate the relationship between pelvic motion and deep fascia displacement in the medial gastrocnemius (MG). Deep fascia displacement of the MG was evaluated through automatic tracking with an ultrasound. Angular variation of the pelvis was determined by 2D kinematic analysis. The average maximum fascia displacement and pelvic motion were 1.501±0.78mm and 6.55±2.47°, respectively. The result of a simple linear regression between fascia displacement and pelvic motion for three task executions by 17 individuals was r=0.791 (P<0.001). Moreover, hamstring flexibility was related to a lower anterior tilt of the pelvis (r=0.544, P<0.024) and a lower deep fascia displacement of the MG (r=0.449, P<0.042). These results support the concept of myofascial tissue connectivity over a distance in an in vivo model, reinforce the functional concept of force transmission through synergistic muscle groups, and grant new perspectives for the role of fasciae in restricting movement in remote zones. © 2015 Anatomical Society. Source


Pereira V.M.,Federal University of Rio de Janeiro | Pereira V.M.,National Institute for Translational Medicine INCT TM | Arias-Carrion O.,Movement Disorders and Transcranial Magnetic Stimulation Unit | Machado S.,Federal University of Rio de Janeiro | And 8 more authors.
International Archives of Medicine | Year: 2013

Introduction. About 45% of women suffer from some form of sexual dysfunction. Despite its high prevalence, there are few studies that have systematically evaluated sex therapy in comparison with other interventions. Objective. Review randomized clinical trials that present psychotherapeutic interventions for female sexual dysfunctions. Method. Through a search in three databases (Medline, Web of Science and PsycInfo), 1419 references were found. After an analysis of the abstracts, twenty-seven articles met the inclusion criteria and composed this review. Results: Sex therapy, as proposed by Masters and Johnson and Heiman and LoPiccolo, is still the most commonly used form of therapy for sexual dysfunctions; although it has shown results, the results do not consistently support that this is the best alternative in the treatment of sexual dysfunctions. Conclusion: There is a lack of systematic study of many female sexual dysfunctions. Orgasmic disorder and sexual pain (vaginismus and dyspaurenia) are the most extensively studied disorders and those in which sex therapy seems to have better outcomes. © 2013 Pereira et al.; licensee BioMed Central Ltd. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Crawford K.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Communications in Computer and Information Science | Year: 2015

Creativity is an inherent aspect to the development of new products, therefore a critical capacity for software development. Indicators to measure creativity are grouped into two main areas: (1) those related to the creative result itself and its quality (including novelty and usefulness) and (2) those related to the creative team itself (considering indicators such as individual and group satisfaction, development of cognitive skills, group interaction,…). From this perspective, the aim of this work is to introduce some ideas for assesing the creativity of software products. © Springer International Publishing Switzerland 2015. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

The set covering problem is a classical problem in the subject of combinatorial optimization that consists in finding a set of solutions that cover a range of needs at the lowest possible cost. The literature reports various techniques to solve this problem, ranging from exact algorithms to approximate methods. In this paper, we present a new XOR-based artificial bee colony algorithm for solving set covering problems. We integrate a XOR operator to binarize the solution construction in order to cope with the binary nature of set covering problems. We also incorporate pre-processing phases and dynamic ABC parameters so as to improve solving time. We report interesting and competitive experimental results on a set of 65 benchmarks from the Beasley’s OR-Library. © Springer International Publishing Switzerland 2016. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Advances in Intelligent Systems and Computing | Year: 2015

Constraint programming allows to solve constraint satisfaction and optimization problems by building and then exploring a search tree of potential solutions. Potential solutions are generated by firstly selecting a variable and then a value from the given problem. The enumeration strategy is responsible for selecting the order in which those variables and values are selected to produce a potential solution. There exist different ways to perform this selection, and depending on the quality of this decision, the efficiency of the solving process may dramatically vary. A main concern in this context is that the behavior of the strategy is notably hard to predict. In this paper, we present a performance evaluation of 24 enumeration strategies for solving constraint satisfaction problems. Our goal is to provide new and interesting knowledge about the behavior of such strategies. To this end, we employ a set of wellknown benchmarks that collect general features that may be present on most constraint satisfaction and optimization problems. We believe this information will be useful to help users making better solving decisions when facing new problems. © Springer International Publishing Switzerland 2015. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Communications in Computer and Information Science | Year: 2015

The Set Covering Problem (SCP) has long been concentrating the interest of many researchers in the field of Combinatorial Optimization. SCP is a 0–1 integer programming problem that consists in finding a set of solutions which allow to cover a set of needs at the lowest cost possible. There are many applications of these kind of problems, the main ones are: location of services, files selection in a data bank, simplification of boolean expressions, balancing production lines, among others. Different metaheuristics have been proposed to solve it. Here, we present the possibilities to solve Set Covering Problems with Harmony Search. © Springer International Publishing Switzerland 2015. Source


Niklander S.,Adolfo Ibanez University | Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | And 3 more authors.
Communications in Computer and Information Science | Year: 2015

The Mass Media involve mechanisms that are intended to reach a wide audience by means of radio, television, newspapers, and Internet, among others. The Mass Media are also responsible for providing the suitable perception of news from different areas such as for instance politics, business, crime, or technology. However, this perception is often manipulated in order to accommodate the information according to a given criteria. This manipulation of the information is suddenly not captured by everyone causing a distortion of the real scenario. In this paper, we illustrate how the use of discourse analysis can improve understanding of such hidden information. We present a case study where this methodology is effectively used to analyze the information provided by news about a social phenomena related to the dehumanization of the female gender. Interesting results are discussed about how this useful methodology could be used to detect communication products that are not usable nor understandable for a wide audience. © Springer International Publishing Switzerland 2015. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Communications in Computer and Information Science | Year: 2015

Optimization problems can be found in several real application domains such as engineering, medicine, mathematics, mechanics, physics, mining, games, design, and biology, among others. There exist several techniques to the efficient solving of these problems, which can be organized in two groups: exact and approximate methods. Metaheuristics are one of the most famous and widely used approximate methods for solving optimization problems. Most of them are known for being inspired on interesting behaviors that can be found on the nature, such as the way in which ants, bees and fishes found food, or the way in which fireflies and bats move on the environment. However, solving optimization problems via metaheuristics is not always a simple trip. In this paper, we analyze and discuss from an usability standpoint how the effort needed to design and implement efficient and robust metaheuristics can be conveniently managed and reduced. © Springer International Publishing Switzerland 2015. Source


Olguin E.,San Sebastian University | Crawford B.,San Sebastian University | Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | And 3 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

If the meetings within the organizations properly fulfill their purposes would be of a high strategic value. However, they are often considered as inefficient and ineffective. The organizations invest time and resources in improving their productions and organizational processes but not in optimizing their meetings. When they do so, usually they do not get the results expected. At first glance, it seems an issue of an easy solution but it is not, because it is connected to the complexity of human beings. The traditional conception associates a meeting with a time or physical space where issues that are in a list of topics are addressed. Through the proposal that we have successfully worked in the organizations we outline that the meetings are rites of conversational networks and organizational processes. This understanding opens a wide range of possibilities and opportunities of optimization. © 2015 AISTI. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

This work presents a study of a new binary cat swarm optimization. The cat swarm algorithm is a recent swarm metaheuristic technique based on the behaviour of discrete cats. We test the proposed binary cat swarm optimization solving the set covering problem which is a well-known NP-hard discrete optimization problem with many practical applications, such as: political districting, information retrieval, production planning in industry, sector location and fire companies, among others. To tackle the mapping from a continuous search space to a discrete search space we use different transfer functions, S-shaped family and V-shaped family, which are investigated in terms of convergence speed and accuracy of results. The experimental results show the effectiveness of our approach where the binary cat swarm algorithm produce competitive results solving a portfolio of set covering problems from the OR-Library. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

To solve the Set Covering Problem we will use a metaheuristic Fireworks Algorithm inspired by the fireworks explosion. Through the observation of the way that fireworks explode is much similar to the way that an individual searches the optimal solution in swarm. Fireworks algorithm (FWA) consists of four parts, i.e., the explosion operator, the mutation operator, the mapping rule and selection strategy. The Set Covering Problem is a formal model for many practical optimization problems. It consists in finding a subset of columns in a zero/one matrix such that they cover all the rows of the matrix at a minimum cost. © Springer International Publishing Switzerland 2016. Source


Salas J.,Pontifical Catholic University of Valparaiso | Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | And 7 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

This paper is intended to generate solutions to Set Covering Problem (SCP) through the use of a metaheuristic. The results were obtained using a variation of Harmony Search called Binary Global-Best Harmony Search Algorithm. To measure the effectiveness of the technique against other metaheuristics, Weasly benchmark was used. © Springer International Publishing Switzerland 2016. Source


Niklander S.,Adolfo Ibanez University | Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | And 3 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

The goal of this work is to reveal the discursive strategies that employ the digital platform of a Chilean mass media to represent the female gender and the corresponding people interaction on social networks with respect to the news. This is important because if we can detect the existence of male hegemony, we could conclude that it is a prevailing ideology and thus corroborate the existence of a patriarchal order in the national press. We take as a starting point that mass media constitute a privileged access platform, because through language they spread a particular world vision, even though the press - as publicly representation - intend to accommodate a wide and heterogeneous set of speeches. The mass media, as active agents in social processes, target imagined, massive, and diverse audiences, because through its discourse, they present fragments and perspectives of the 'reality' with which hide, describe, make visible, ignore or reinforce constructions and ideologies. When analyzing the modes of representation of the female gender, we observe how they refer to the women, generating an important and motivating challenge that will allow us to detect and describe how the subordination of the female gender is manifested in a particular social time. © 2015 AISTI. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 8 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

The Set Covering Problem (SCP) is a matrix that is composed of zeros and ones and consists in finding a subset of zeros and ones also, in order to obtain the maximum coverage of necessities with a minimal possible cost. In this world, it is possible to find many practical applications of this problem such as installation of emergency services, communications, bus stops, railways, airline crew scheduling, logical analysis of data or rolling production lines. SCP has been solved before with different nature inspired algorithms like fruit fly optimization algorithm. Therefore, as many other nature inspired metaheuristics which imitate the behavior of population of animals or insects, Artificial Fish Swarm Algorithm (AFSA) is not the exception. Although, it has been tested on knapsack problem before, the objective of this paper is to show the performance and test the binary version of AFSA applied to SCP, with its main steps in order to obtain good solutions. As AFSA imitates a behavior of a population, the main purpose of this algorithm is to make a simulation of the behavior of fish shoal inside water and it uses the population as points in space to represent the position of fish in the shoal. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

In software project management there are several problems to deal, one of those is the Software Project Scheduling Problem (SPSP). This problem requires to assign a set of resources to tasks for a given project, trying to decrease the duration and cost of the whole project. The workers and their skills are the main resources in the project. In this paper we present the SPSP as a combinatorial optimization problem and a novel approach to solve SPSP by a Firefly algorithm. Firefly algorithm is a new metaheuristic based on the behaviour of the firefly. We present the design of the resolution model to solve the SPSP using an algorithm of fireflies and we illustrate some experimental results in order to demonstrate the viability and soundness of our approach. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

The Weighted Set Cover Problem (SCP) is a popular optimization problem that has been applied to different industrial applications, including scheduling, manufacturing, service planning and location problems. It consists in to find low cost solutions covering a set of requirements or needs. In this paper, we solve the SCP using a recent nature inspired algorithm: Invasive Weed Optimization (IWO). IWO imitates the invasive behavior of real weeds: natural reproduction and selection where the best weed has more chance of reproduction. We test our approach using known ORLIB test problems for the SCP. The computational results show that the IWO metaheuristic can find very good results. © Springer International Publishing Switzerland 2016. Source


Salvande M.,University of Santiago de Compostela | Figueroa J.A.,Pontifical Catholic University of Valparaiso | Figueroa J.A.,University of Santiago de Chile | Figueroa J.A.,Central University of Chile | And 2 more authors.
Bosque | Year: 2011

The quantity component of the disperser effectiveness of resident birds during the autumn-winter period has not yet been detailed in temperate rainforests of South America. In this study, the potentially frugivorous bird species in the temperate rainforests of southern Chile during the Austral autumn-winter were identified, and the quantity component of the disperser effectiveness of the birds (number of visits and number of seeds dispersed per hour) were evaluated for the tree species Luma apiculata and Aextoxicon punctatum. During the peak fruiting period of the both L. apiculata and A. punctatum 10 and 14, respectively, individuals of each species were monitored for a total of 10 days. Results show that four bird species consumed L. apiculata fruits. The birds Turdus falcklandii were the main fruit consumers (72 % of the visits), with a mean rate of 2.2 visits per hour and 49.2 seeds dispersed per hour. The frugivorous species visiting A. punctatum were T. falcklandii (97 % of the visits) and Columba araucana (3 %). In A. punctatum, T. falcklandii consumed 65 fruits in 35 visits, with a mean rate of 1.8 visits per hour and 3.4 seeds dispersed per hour. In conclusion, T. falcklandii would be the most effective seed disperser bird for autumn-winter fruiting trees in the Chiloé rainforest of our study site, at least with regard to the quantitative component of disperser effectiveness. Source


Isah A.O.,Minna Federal University Of Technology | Alhassan J.K.,Minna Federal University Of Technology | Misra S.,Covenant University | Idris I.,Minna Federal University Of Technology | And 5 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

This research work is to bring to light, the danger posed by Cyber Crime in the world generally and Nigeria in particular with the hope that policy makers will work with the recommendations and practical combating framework design of this research work. In order to achieve this, the following approaches were adopted; survey of some common Cybercrime in Nigeria with the frequency of occurrence and design of a frame work system to combat the crime. The system design controls and track cyber criminals on the Nigerian cyber space. The paper proposes the establishment of National Cybercrime Control Center (NCCC) to effect this system. The Security Agents could obtain tracked information from NCCC as evidence to arrest and prosecute cybercriminals. © Springer International Publishing Switzerland 2016. Source


Figueroa J.A.,Pontifical Catholic University of Valparaiso | Figueroa J.A.,Central University of Chile | Figueroa J.A.,University of Santiago de Chile | Cavieres L.A.,University of Concepcion | Cavieres L.A.,Institute Ecologia y Biodiversidad IEB
Revista Chilena de Historia Natural | Year: 2012

We studied the effect of heat shock and wood-fueled smoke on the emergence of native and exotic plant species in soil samples obtained in an evergreen matorral of central Chile that has been free of fire for decades. It is located on the eastern foothills of the Andes Range in San Carlos de Apoquindo. Immediately after collection samples were dried and stored under laboratory conditions. For each two transect, ten samples were randomly chosen, and one of the following treatments was applied: (1) heat-shock treatment, (2) plant-produced smoke treatment, (3) combined heat-and-smoke treatment, and (4) control, corresponding to samples not subjected to treatment. Twenty-seven species, representing 13 families, emerged from the soil samples. The most abundant families were Asteraceae and Poaceae. All of the emerged species were herbaceous, and 18 species were exotic. Respect to general hypothesis, there is no evidence for the proposition that fire-free matorral has lower proportion of exotic and native species with fire-related cues than matorral with fires. Among the exotic and native, the mean number of species that emerged from soil samples did not change significantly with respect to the control for any of the treatments applied. Nevertheless, important species-specific responses were observed. Smoke and heat-smoke combination significantly increased the emergence of the exotic species Anthriscus caucalis. While smoke-related cues significantly increased the emergence of the exotic species Avena barbata, the emergence of the exotic Aphanes arvensis and the native Bromus berteroanus decreases. For several species our results showed inconsistent responses to fire-related cues compared to those reported in the literature. We suggest that these differences might be related with the fire-history in the populations, an important issue poorly acknowledge in the literature. © Sociedad de Biología de Chile. Source


Rubio A.G.,Pontifical Catholic University of Valparaiso | Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | And 8 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

There are multiple problems in several industries that can be solved with combinatorial optimization. In this sense, the Set Covering Problem is one of the most representative of them, being used in various branches of engineering and science, allowing find a set of solutions that meet the needs identified in the restrictions that have the lowest possible cost. This paper presents an algorithm inspired by binary black holes (BBH) to resolve known instances of SPC from the OR-Library. Also, it reproduces the behavior of black holes, using various operators to bring good solutions. © Springer International Publishing Switzerland 2016. Source


Jaramillo A.,Pontifical Catholic University of Valparaiso | Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | And 8 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

The Soccer League Competition algorithm (SLC) is a new nature-based metaheuristic approach to solve optimization problems. It gets its basis model from the interaction between soccer teams and their players in a soccer league competition, where each player (feasible solution) compete for victory and be the best player. This paper presents a review of the underlaying SLC model and a practical approach to solve the Set Covering Problem using SLC and Python as programming language and tested over a widely OR-Library SCP benchmarks to obtain convergence capability and effectiveness of the implementation. © Springer International Publishing Switzerland 2016. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 6 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

In constraint programming, efficiency in the resolution process can be affected by the order in which the variables of the problem and the domain values are selected. This activity is known as enumeration. At the beginning, it is difficult to determine the best choice variable-value pair that can generate potential solutions for constraint satisfaction problems. In this paper, we present an evaluation of different enumeration strategies, based on performance exhibited in a set indicators. These strategies solve different instances of constraint problems satisfactions. The results show that it is feasible to solve constraint satisfaction with at least one strategy enumeration. © 2015 AISTI. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 8 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

The Manufacturing Cell Design is a problem that consist in organize machines in cells to increase productivity, i.e., minimize the movement of parts for a given product between machines. In order to solve this problem we use a Dolphin Echolocation algorithm, a recent bio-inspired metaheuristic based on a dolphin feature, the echolocation. This feature is used by the dolphin to search all around the search space for a target, then the dolphin exploits the surround area in order to find promising solutions. Our approach has been tested by using a set of 10 benchmark instances with several configurations, reaching to optimal values for all of them. © Springer International Publishing Switzerland 2016. Source


Castro S.A.,University of Santiago de Chile | Castro S.A.,Chilean Center of Nanosciences and Nanotechnology | Figueroa J.A.,Central University of Chile | Escobedo V.,University of Santiago de Chile
Revista Brasileira de Botanica | Year: 2016

The hoary mustard (Hirschfeldia incana (L.) Lagr.-Foss.) is a recently alien weed in Chile, recording a rapid increase in local abundance and spread. This species is distributed mainly on urban ecosystems, and field observations suggest that seed germination may have a key role to understanding its population persistence. In this line, it has been suggested that a successful germination strategy for weeds is to have both persistent seeds in the soil as rapidly germinable seeds, extending the ability to germinate over time. We evaluated germination of seeds of H. incana according to different harvest years (2010, 2011, and 2012), searching to understand how harvest time affects seed germination. For this proposal, seeds were cultivated at different temperatures (eight levels between 5 and 40 °C), covering a wide thermal gradient. Our results showed a lower germination percentage (43 %) in seed harvested in 2012 compared to the harvested in 2010 and 2011 (both cases >60 %), supporting that Hirschfeldia delay seed germination but keeping a seed stock able to germinate the same year in which were produced. The maximum germination percentage (>80 %) occurred with temperatures between 20 and 35 °C, and germination did not occur at 5 °C. These results suggest that temperature is not limiting the geographical spread of H. incana in Chile, as temperatures <5 °C are unusual. Thus, we expect that H. incana may increase its local abundance and latitudinal spread, if appropriate measures are not taken in Chile. © 2015, Botanical Society of Sao Paulo. Source


Darrigrande M.C.,Central University of Chile | Darrigrande M.C.,Magister University | Darrigrande M.C.,University of Chile | d'Alencon L.M.V.,University of Chile | And 4 more authors.
AUS | Year: 2015

This article addresses the issue of architecture dissemination, specifically from what tourism magazines attempted to advertise as urban destinations in 1930-1960, in line with the great reforms conducted in main Chilean cities. For this purpose, a comparison is made between what the projects essentially sought to generate -through a civic and representative architecture- and the touristic conception that promoted them as destinations based on the new urban landscapes that made them up. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Scientific Programming | Year: 2016

The Machine-Part Cell Formation Problem (MPCFP) is a NP-Hard optimization problem that consists in grouping machines and parts in a set of cells, so that each cell can operate independently and the intercell movements are minimized. This problem has largely been tackled in the literature by using different techniques ranging from classic methods such as linear programming to more modern nature-inspired metaheuristics. In this paper, we present an efficient parallel version of the Migrating Birds Optimization metaheuristic for solving the MPCFP. Migrating Birds Optimization is a population metaheuristic based on the V-Flight formation of the migrating birds, which is proven to be an effective formation in energy saving. This approach is enhanced by the smart incorporation of parallel procedures that notably improve performance of the several sorting processes performed by the metaheuristic. We perform computational experiments on 1080 benchmarks resulting from the combination of 90 well-known MPCFP instances with 12 sorting configurations with and without threads. We illustrate promising results where the proposal is able to reach the global optimum in all instances, while the solving time with respect to a nonparallel approach is notably reduced. © 2016 Ricardo Soto et al. Source


Lorenzetti D.,National institute for astrophysics | Giannini T.,National institute for astrophysics | Larionov V.M.,Central University of Chile | Arkharov A.A.,Central Astronomical Observatory of Pulkovo | And 6 more authors.
Astrophysical Journal | Year: 2011

We present the results of a simultaneous monitoring, lasting more than two years, of the optical and near-infrared photometric and polarimetric activity of the variable protostar PV Cep. During the monitoring period, an outburst with declining phase (ΔJ ≈ 3mag) lasting about 120days occurred in all the photometric bands. A time lag of 30days between optical and infrared light curves has been measured and interpreted in the framework of an accretion event. This latter is directly recognizable in the significant variations of the near-infrared colors, which appear bluer in the outburst phase, when the star dominates the emission, and redder in the declining phase, when the disk emission prevails. All the observational data have been combined to derive a coherent picture of the complex morphology of the whole PV Cep system that is composed of, in addition to the star and the accretion disk, a variable bi-conical nebula. The mutual interaction between all these components is the cause of the high value of the polarization (≈ 20%) and of its fluctuations. The observational data concur to indicate that PV Cep is not a genuine EXor star, but rather a more complex object; moreover, the case of PV Cep leads to arguments about the classification of other recently discovered young sources in outburst that have been considered, perhaps oversimplifying, as EXor. © 2011. The American Astronomical Society. All rights reserved. Source


Machado S.,Federal University of Rio de Janeiro | Machado S.,National Institute of Translational Medicine INCT TM | Machado S.,Central University of Chile | Machado S.,Federal University of Uberlandia | And 9 more authors.
Salud Mental | Year: 2013

Introduction: Our understanding of functional brain organization is due to advances in neuroimaging technologies and intensive clinical research. Recently, cognitive science (cognitive neuroscience), combined with advances in technology, have changed our understanding of brainbehavior relationship. This symbiotic relationship has allowed a better characterization of the lesion site in patients with brain disorders and patterns of activation in healthy subjects. Objective: In this article we discuss the contribution of the left hemisphere and right hemisphere involvement in the regulation of motor behavior; this will allow us to better understand the lateralization of motor functions. Development: The results support the view of a left hemisphere dominance for language and motor control, and a right hemisphere dominance for spatial functions and attention. Specialized areas are probably predetermined and certain functions are lateralized to one or other hemisphere due to the efficient organization and information processing in the brain. Conclusion: In the studies reviewed, specific functions for each hemisphere were observed, suggesting the existence of a complex organization that recruits several areas of the Nervous System for proper task performance. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 8 more authors.
Mathematical Problems in Engineering | Year: 2015

The Set Covering Problem consists in finding a subset of columns in a zero-one matrix such that they cover all the rows of the matrix at a minimum cost. To solve the Set Covering Problem we use a metaheuristic called Binary Cat Swarm Optimization. This metaheuristic is a recent swarm metaheuristic technique based on the cat behavior. Domestic cats show the ability to hunt and are curious about moving objects. Based on this, the cats have two modes of behavior: seeking mode and tracing mode. We are the first ones to use this metaheuristic to solve this problem; our algorithm solves a set of 65 Set Covering Problem instances from OR-Library. © 2015 Broderick Crawford et al. Source


Crawford B.,University of Chile | Crawford B.,Finis Terrae University | Crawford B.,San Sebastian University | Soto R.,University of Chile | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2015

This research present an applied case of the resolution of a timetabling problem called the University course Timetabling problem (UCTP), the resolution technique used is based in Ant Colony Optimization metaheuristic. Ant Colony Optimization is a Swarm Intelligence technique which inspired from the foraging behavior of real ant colonies. We propose a framework to solve the University course Timetabling problem effectively. We show the problem and the resolution design using this framework. First we tested our proposal with some competition instances, and then compare our results with other techniques. The results show that our proposal is feasible and competitive with other techniques. To evaluate this framework in practice way, we build a real instance using the case of the school of Computer Science Engineering of the Pontifical Catholic University of Valparaíso and the Department of Computer Engineering at Playa Ancha University. © Springer International Publishing Switzerland 2015. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Advances in Intelligent Systems and Computing | Year: 2015

Autonomous search is a recent approach that allows the solver to adapt their search so as to be more efficient without the manual configuration of an expert user. The goal is to provide more capabilities to the solver in order to improve the search process based on some performance indicators and self-tuning. This approach has effectively been applied to different optimization and satisfaction techniques such as constraint programming, SAT, and various metaheuristics. This paper focuses on automated self-tuning of constraint programming solvers. We employ a classic decision making method called weighted sum model (WSM) to evaluate the search process performance. This evaluation is used by the solver to re-configure its parameters in benefit of reaching a better performance. However, reaching good configurations straightly depends on the correct tuning of the WSM. This is known to be hard as the WSM is problem-dependent and good settings are not commonly stable along the search. To this end, we introduce a gravitational search algorithm (GSA), which is able to find good WSM configurations when solving constraint satisfaction problems. We illustrate experimental results where the GSA-based approach directly competes against previously reported autonomous search methods for constraint programming. © Springer International Publishing Switzerland 2015. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Advances in Intelligent Systems and Computing | Year: 2015

The set covering problem is a classic benchmark that has many real applications such as positioning of communications systems, logical analysis, steel production, vehicle routing, and service allocation in general. In this paper, we present an improved firefly algorithm to the efficient resolution of this problem. The firefly algorithm is a recent metaheuristic based on the flashing characteristics of fireflies that attract each other by using their brightness. We improve this approach by incorporating pre-processing and an heuristic feasibility operator resulting in an interesting solver able to clearly outperform the previously reported results obtained from firefly algorithms. © Springer International Publishing Switzerland 2015. Source


Niklander S.,Adolfo Ibanez University | Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | And 3 more authors.
Communications in Computer and Information Science | Year: 2015

The Mass Media involves information and communication products targeted to a wide audience. Today such communications products are also available on Internet where people can react to a given information by posting critics, congratulations, opinions or whatever they want via social networks. Such reactions are considered valuable information for instance to government and companies. However, this information is hard to automatically process as people commonly use ironies, stereotypes, metaphors expressed in informal writing plenty of chat abbreviations, emoticons, and slang words. In this paper, we illustrate how tools based on discursive categories can be used to analyze such reactions and thus to process and understand the information behind them. © Springer International Publishing Switzerland 2015. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Advances in Intelligent Systems and Computing | Year: 2015

The Electromagnetism-like algorithm is a relatively modern metaheuristic based on the attraction-repulsion mechanism of particles in the context of electromagnetism theory. This paper focuses on improving performance of this metaheuristic when solving binary problems. To this end, we incorporate three elements: pre-processing, repairing, and transfers functions. The pre-processing allows to reduce the size of instances, while repairing eliminates those potential solutions that violate the constraints. Finally, the incorporation of a transfer function adapts the solutions to a binary domains. We illustrate experimental results where the incorporation of these elements improve the resolution phase, when solving a set of 65 non-unicost set covering problems. © Springer International Publishing Switzerland 2015. Source


Antoine C.,University of the Pacific of Chile | Carmona J.,Central University of Chile
Profesional de la Informacion | Year: 2014

The concept of museum communication is examined from the perspective of the professionals in charge of this task, characterizing the practical circumstances, perceptions, and specifics of the communication area. Through a series of interviews with managers of a group of Chilean museums, we identified elements to consider and problems that often affect museum communications in general, despite the diversity of these institutions. In the museums examined, we observed different ways of understanding the concept of communication. Such differences are linked to geographical location, ownership or affiliation, as well as other dimensions of the museum such as mission, objectives of the institution, and the communications vision. Source


Classen-Bockhoff R.,Johannes Gutenberg University Mainz | Bull-Herenu K.,Central University of Chile | Bull-Herenu K.,University of Santiago de Chile
Annals of Botany | Year: 2013

Backgrounds and Aims Conceptual and terminological conflicts in inflorescence morphology indicate a lack of understanding of the phenotypic diversity of inflorescences. In this study, an ontogeny-based inflorescence concept is presented considering different meristem types and developmental pathways. By going back to the ontogenetic origin, diversity is reduced to a limited number of types and terms. Methods Species from 105 genera in 52 angiosperm families are investigated to identify their specific reproductive meristems and developmental pathways. Based on these studies, long-term experience with inflorescences and literature research, a conceptual framework for the understanding of inflorescences is presented. Key Results Ontogeny reveals that reproductive systems traditionally called inflorescences fall into three groups, i.e. 'flowering shoot systems' (FSS), 'inflorescences' sensu stricto and 'floral units' (FUs). Our concept is, first, based on the identification of reproductive meristem position and developmental potential. The FSS, defined as a seasonal growth unit, is used as a reference framework. As the FSS is a leafy shoot system bearing reproductive units, foliage and flowering sequence play an important role. Second, the identification of two different flowerproducing meristems is essential. While 'inflorescence meristems' (IMs) share acropetal primordia production with vegetative meristems, 'floral unit meristems' (FUMs) resemble flower meristems in being indeterminate. IMs produce the basic inflorescence types, i.e. compound and simple racemes, panicles and botryoids. FUMs give rise to dense, often flower-like units (e.g. heads). They occur solitarily at the FSS or occupy flower positions in inflorescences, rendering the latter thyrses in the case of cymose branching. Conclusions The ontogenetic concept differs from all existing inflorescence concepts in being based on meristems and developmental processes. It includes clear terms and allows homology statements. Transitional forms are an explicit part of the concept, illustrating the ontogenetic potential for character transformation in evolution.©The Author 2013. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. Source


Bull-Herenu K.,Central University of Chile | Bull-Herenu K.,University of Santiago de Chile | Classen-Bockhoff R.,Johannes Gutenberg University Mainz
Annals of Botany | Year: 2013

Backgrounds and Aims Current research in plant science has concentrated on revealing ontogenetic processes of key attributes in plant evolution. One recently discussed model is the 'transient model' successful in explaining some types of inflorescence architectures based on two main principles: the decline of the so called 'vegetativeness' (veg) factor and the transient nature of apical meristems in developing inflorescences. This study examines whether both principles find a concrete ontogenetic correlate in inflorescence development. Methods To test the ontogenetic base of veg decline and the transient character of apical meristems the ontogeny of meristematic size in developing inflorescences was investigated under scanning electron microscopy. Early and late inflorescence meristems were measured and compared during inflorescence development in 13 eudicot species from 11 families. Key Results The initial size of the inflorescence meristem in closed inflorescences correlates with the number of nodes in the mature inflorescence. Conjunct compound inflorescences ( panicles) show a constant decrease of meristematic size from early to late inflorescence meristems, while disjunct compound inflorescences present an enlargement by merging from early inflorescence meristems to late inflorescence meristems, implying a qualitative change of the apical meristems during ontogeny. Conclusions Partial confirmation was found for the transient model for inflorescence architecture in the ontogeny: the initial size of the apical meristem in closed inflorescences is consistent with the postulated veg decline mechanism regulating the size of the inflorescence. However, the observed biphasic kinetics of the development of the apical meristem in compound racemes offers the primary explanation for their disjunct morphology, contrary to the putative exclusive transient mechanism in lateral axes as expected by the model.©The Author 2013. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

Cuckoo search is a modern bio-inspired metaheuristic that has successfully been used to solve different real world optimization problems. In particular, it has exhibited rapid convergence reaching considerable good results. In this paper, we employ this technique to solve the set covering problem, which is a well-known optimization benchmark. We illustrate interesting experimental results where the proposed algorithm is able to obtain several global optimums for different set covering instances from the OR-Library. © 2015 AISTI. Source


Pandey P.S.,Indian Institute of Information Technology Allahabad | Purohit N.,Indian Institute of Information Technology Allahabad | Mishra S.,Covenant University | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The nodes of a communication network use network coding technique for generating packets for output links by systematically processing the packets received on its input links such that the original packets should be recovered by the destination nodes. Under low traf- fic conditions higher bandwidth efficiency and power efficiency can be achieved using network coding but the performance degrades as the traf- fic in the network increases. Overall performance of the network can be improved if the node is able to take a decision about whether to use or not to use network coding under the current condition of the network. This work presents a scheme for finding out a threshold value below which network coding should be used and above the threshold normal forwarding operation should be adopted by the nodes. The performance of the proposed algorithm on Cross topology under different network coding schemes has been tested under simulation environment i.e. on NS-3. Significant improvement has been observed as compared to only network coded systems as well as the traditional store and forward systems. © Springer International Publishing Switzerland 2015. Source


Machado S.,Federal University of Rio de Janeiro | Machado S.,Central University of Chile | Machado S.,Salgado de Oliveira University | Machado S.,Federal University of Uberlandia | And 12 more authors.
Clinical Practice and Epidemiology in Mental Health | Year: 2013

This study aims to compare the topographic distribution of cortical activation between real and imagined movement through event-related potential (ERP). We are specifically interested in identifying, the topographic distribution of activated areas, the intensity of activated areas, and the temporal occurrence of these activations on preparation and motor response phases. Twelve healthy and right handed subjects were instructed to perform a task under real and imagery conditions. The task was performed simultaneously to electroencephalographic (EEG) recording. When compared the conditions, we found a statistically significant difference in favor of real condition revealed by performing an unpaired t-test with multiple corrections of Bonferroni, demonstrating negative activity on electrode C3 and positive activity on the electrode C4 only in motor response phase. These findings revealed similar functional connections established during real and imagery conditions, suggesting that there are common neural substrate and similar properties of functional integration shared by conditions. © Machado et al.; Licensee Bentham Open. Source


We report the "Northern 2n=38-40, modifi cation 1" race from three localities of the Liolaemus monticola complex in Chile that appears to be chromosomally and geographical intermediate between two previously described "Northern 2n=38-40" and "Multiple Fission, 2n=40-44 (MF)" races. This race retains the same "Northern" chromosomal features, but differs by being both polymorphic for an enlarged chromosome pair 6 and for a pericentric inversion in chromosome pair 7; these rearrangements are present in the "MF" race. At the population cytogenetics level, the mean proportion of polymorphic chromosomes in the "Northern, mod 1" race is relatively high and intermediate between the Northern" and "MF" races, while the chromosome "alleles" in the "Northern, mod 1" race deviate from the Hardy-Weinberg ratio higher than the aforementioned races. The Roger's distance between samples are in concordance with the chromosome races and the proposals barriers (The Colorado river and the Juncal river). The lowest chromosome "alleles" flux values (Nm) are between the chromosomal races, suggesting a low chromosomal introgression. These population cytogenetics patterns, plus the origin of the chromosomal rearrangements, and the recombination patterns resulting from chromosomal heterozygosity are compared with the situation of other populations of the "Northern" and the "MF" races previously described. We discuss the possible "Northern, mod 1" hybrid status in the evolution of this complex in central Chile. Source


Elisa Irarrazaval M.,Instituto Oncologico Fundacion Arturo Lopez Perez | Rodriguez P.F.,Central University of Chile | Fasce G.,Instituto Oncologico | Silva F.W.,Instituto Oncologico Fundacion Arturo Lopez Perez | And 5 more authors.
Revista Medica de Chile | Year: 2013

Background: Quality of Life assessment in oncologic patients evaluates the impact and sequels of the disease and the adverse effects of available treatments. Aim: To validate in Chile the breast cancer specific-questionnaire (BR23) developed by the European Organization for Research and Treatment of Cancer (EORTC). Patients and Methods: After performing a linguistic validation of the BR23 according to EORTC instructions, its psychometric properties were tested in 103 patients with breast cancer whose ages ranged from 34 to 83 years. Internal consistency of the scales was assessed using the Cronbach's alpha coefficient. The test-retest correlations of each scale (n = 83) were evaluated. The correlation of BR23 scales with SF36 version 2 and C30 version 3.0 scales was also assessed. The sensitivity and specificity of the instrument were analyzed using receiver operating characteristic curves (ROC). Results: Alpha values showed acceptable levels of internal consistency, ranging between 0.702 and 0.917 in all scales of BR23. The statistical analysis revealed significant test-retest correlations in most scales of BR23. The correlations between BR23 and similar domains of C30 and SF36 questionnaires were also significant. The BR23 questionnaire demonstrated satisfactory levels of sensitivity and specificity when compared with the SF-36 scale. Conclusions: The BR23 questionnaire adapted for use in Chile is linguistically appropriate and psychometrically valid. Source


Gonzalez P.A.,Central University of Chile | Gonzalez P.A.,Diego Portales University | Vasquez Y.,University of the Frontier
Journal of High Energy Physics | Year: 2011

We study the three-dimensional gravity with torsion given by the Mielke- Baekler (MB) model coupled to gravitational Chern-Simons term, and that possess electric charge described by Maxwell-Chern-Simons electrodynamics. We find and discuss this theory's charged black holes solutions and uncharged solutions. We find that for vanishing torsion our solutions by means of a coordinate transformation can be written as three-dimensional Chern-Simons black holes. We also discuss a special case of this theory, Topologically Massive Gravity (TMG) at chiral point, and we show that the logarithmic solution of TMG is also a solution of theMB model at a fixed point in the space of parameters. Furthermore, we show that our solutions generalize Gödel type solutions in a particular case. Also, we recover BTZ black hole in Riemann-Cartan spacetime for vanishing charge. © 2011 SISSA. Source


Ajani Y.,Johannes Gutenberg University Mainz | Bull-Herenu K.,University of Santiago de Chile | Bull-Herenu K.,Central University of Chile | Classen-Bockhoff R.,Johannes Gutenberg University Mainz
Flora: Morphology, Distribution, Functional Ecology of Plants | Year: 2016

Apiaceae is a large family characterized by uniform flowers. However, early ontogenetic studies revealed unexpected diversity in flower development. In the present paper, we investigate eight species representing six tribes of subfamily Apioideae to address diversity in developmental patterns. One focus is on the developmental divergence of sex morphs in andromonoecious species. Scanning electron microscopic studies were conducted on six herbaceous species: Chaerophyllum bulbosum, Daucus carota, Dorema aucheri, Ferula hezarlalehzarica, Orlaya grandiflora, Pastinaca sativa, and two woody species, i.e., Bupleurum fruticosum and Seseli ghafoorianum. Our results confirm the existence of at least three different flower developmental patterns in Apioideae. Main differences among species concern: (i) centripetal vs. divergent initiation of floral organs, (ii) subsequent vs. simultaneous timing of primordium formation, (iii) single primordium vs. primordium group appearance, and (iv) presence vs. absence of a calyx. As the mature flowers look almost the same, we conclude that spatial constraints and developmental acceleration may trigger differences in flower development. Functionally male flowers show the same development pattern as hermaphroditic flowers except for the gynoecium, which gets inhibited at a late stage of development. This late suppression in development is in line with the plastic response in sex ratio in andromonoecious species. © 2016 Elsevier GmbH. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 9 more authors.
Swarm and Evolutionary Computation | Year: 2016

Constraint Programming is a powerful paradigm which allows the resolution of many complex problems, such as scheduling, planning, and configuration. These problems are defined by a set of variables and a set of constraints. Each variable has non-empty domain of possible value and each constraint involves some subset of the variables and specifies the allowable combinations of values for that subset. The resolution of these problems is carried out by a constraint satisfaction solver which explores a search tree of potential solutions. This exploration is controlled by the enumeration strategy, which is responsible for choosing the order in which variables and values are selected to generate the potential solution. There exist different ways to perform this selection, and depending on the quality of this decision, the efficiency of the solving process may dramatically vary. Autonomous search is a particular case of adaptive systems that aims at improving its solving performance by adapting itself to the problem at hand without manual configuration of an expert user. The goal is to improve their solving performance by modifying and adjusting themselves, either by self-adaptation or by supervised adaptation. This approach has been effectively applied to different optimization and satisfaction techniques such as constraint programming, metaheuristics, and SAT. In this paper, we present a new Autonomous Search approach for constraint programming based on four modern bio-inspired metaheuristics. The goal of those metaheuristics is to optimize the self-tuning phase of the constraint programming search process. We illustrate promising results, where the proposed approach is able to efficiently solve several well-known constraint satisfaction problems. © 2016 Elsevier B.V. Source


Pulgar J.,Andres Bello University | Lagos P.,Andres Bello University | Maturana D.,Andres Bello University | Valdes M.,Andres Bello University | And 2 more authors.
Journal of Fish Biology | Year: 2015

The effect of UV radiation on habitat use of two species of intertidal fishes that inhabit the same pools but exhibit different activity levels and diets was measured: the highly active omnivorous Girella laevifrons and the cryptic carnivorous Graus nigra. Individuals of each species were acclimated to a tank divided in three sections with different illumination; no light (NL), ultraviolet light (UV) and white light (WL), and the time spent and number of visits to each section were recorded. Although both species preferred the NL section, G. laevifrons spent more time in UV and less time in WL compared with G. nigra; G. laevifrons also displayed higher number of visits to UV, suggesting a different tendency in space use in response to UV exposure in intertidal fishes. © 2015 The Fisheries Society of the British Isles. Source


King A.L.S.,Federal University of Rio de Janeiro | King A.L.S.,National Institute for Translational Medicine INCT TM | Valenca A.M.,Federal University of Rio de Janeiro | Valenca A.M.,National Institute for Translational Medicine INCT TM | And 10 more authors.
Clinical Practice and Epidemiology in Mental Health | Year: 2014

Panic disorder refers to the frequent and recurring acute attacks of anxiety. Objective: This study describes the routine use of mobiles phones (MPs) and investigates the appearance of possible emotional alterations or symptoms related to their use in patients with panic disorder (PD). Background: We compared patients with PD and agoraphobia being treated at the Panic and Respiration Laboratory of The Institute of Psychiatry, Federal University of Rio de Janeiro, Brazil, to a control group of healthy volunteers. Method: An MP-use questionnaire was administered to a consecutive sample of 50 patients and 70 controls. Results: People with PD showed significant increases in anxiety, tachycardia, respiratory alterations, trembling, perspiration, panic, fear and depression related to the lack of an MP compared to the control group. Conclusions: Both groups exhibited dependence on and were comforted by having an MP; however, people with PD and agoraphobia showed significantly more emotional alterations as well as intense physical and psychological symptoms when they were apart from or unable to use an MP compared to healthy volunteers. © King et al.; Licensee Bentham Open. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Mathematical Problems in Engineering | Year: 2015

Constraint programming effectively solves constraint satisfaction and optimization problems by basically building, pruning, and exploring a search tree of potential solutions. In this context, a main component is the enumeration strategy, which is responsible for selecting the order in which variables and values are selected to build a possible solution. This process is known to be quite important; indeed a correct selection can reach a solution without failed explorations. However, it is well known that selecting the right strategy is quite challenging as their performance is notably hard to predict. During the last years, adaptive enumeration appeared as a proper solution to this problem. Adaptive enumeration allows the solving algorithm being able to autonomously modifying its strategies in solving time depending on performance information. In this way, the most suitable order for variables and values is employed along the search. In this paper, we present a new and more lightweight approach for performing adaptive enumeration. We incorporate a powerful classification technique named Top- k in order to adaptively select strategies along the resolution. We report results on a set of well-known benchmarks where the proposed approach noticeably competes with classical and modern adaptive enumeration methods for constraint satisfaction. © 2015 Ricardo Soto et al. Source


de la Barra C.L.,Pontifical Catholic University of Valparaiso | Galdames S.,Pontifical Catholic University of Valparaiso | Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | And 5 more authors.
Communications in Computer and Information Science | Year: 2015

There is a common agreement that Leadership is represented by two main ideas: direction and influence. The first related to the knowledge of where the organization should be oriented and the second with the capacity to mobilize others towards that direction. Recent research has rejected these assumptions, stating emphatically that the power of organizations and teams are not in these mythical figures (as the super leader), but in the knowledge shared by all its members. Thus, finding the right direction and success on the path undertaken shall not rest in the hands of one person, but in the capabilities of the entire group. This paper analyses how this approach to leadership can be observed in software development teams, specifically through agilists methods (Extreme Programming). © Springer International Publishing Switzerland 2015. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Communications in Computer and Information Science | Year: 2015

In this paper we address a recent situation created by the explosive growth of web systems. For these reason we propose a framework to support adaptive elements in Web pages. Web pages can be accessed by different platforms with different browsers and through different devices such as laptops, tablets or cellphones. In particular we focus on adaptive menus for this different kind of devices or browsers to optimize the selection patterns and their implementations. We propose a framework using an Adaptive Constraint Programming technique to optimize the decision of developers. Constraint Programming is a programming paradigm able to find efficient resolution in optimization problems. In Constraint Programming a problem is defined in term of variables and constraints. The variables hold a domain and represent the unknowns of the problem, while the relations among them are modeled as constraints. © Springer International Publishing Switzerland 2015. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Communications in Computer and Information Science | Year: 2015

We present an approach to solve the Resource Constrained Project Scheduling Problem. This problem consists on executing a group of activities limited by constraints. Precedence relationships force to some activities to begin after the finalization of others. In addition, processing every activity requires a predefined amount of limited resources. The target of this problem is to minimize the duration of whole project. In this paper, an approach based on Artificial Bee Colony algorithm for the Resource Constrained Project Scheduling Problem is presented. That algorithm is one of the most recent algorithms in the domain of the collective intelligence who was motivated by the intelligent behavior observed in the domestic bees to take the process of forage. Thus, ABC combines methods of local search and global search, trying to balance the process of the exploration and exploitation of the space of search. © Springer International Publishing Switzerland 2015. Source


During an expedition to the Inka Trail at Socoroma, Parinacota Province, XV Region of Chile; about 3150 m altitude, we found a population of Eremocharis confinis I.M.Johnst. (Apiaceae-Umbelliferae), a new adding for the flora of Chile.That species was described by I.M. Johnston at neighboring Perú, at a locality named Candarave, at the Departamento de Tacna. With this found, Eremocharis had two species in Chile: the desertic-schrub E. fruticosa Phil. and the new altiplanic E. confinis. Source


Teillier S.,Central University of Chile | Figueroa J.A.,Pontifical Catholic University of Valparaiso | Castro S.A.,Chilean Center of Nanosciences and Nanotechnology
Gayana - Botanica | Year: 2010

Central Chile supports a rich native flora and a high proportion of alien, naturalized plants. To increase our knowledge about behavior of naturalized plants in central Chile, the flora of the western slope of the Coastal Range (Province Valparaiso, 33°S lat.), was recorded and analyzed. Study sites were placed at natural and anthropic, perturbed areas. Taxonomic richness, species composition, geographic origin, Raunkiaer's life forms, and absolute coverage were recorded. Of the 325 vascular plant species were identified, 110 (34%) were considered alien; 74% of them with European origin, and 10%, European-North African. According to abundance, 27 % of the plant coverage was of native species and 73% of non-natives. The natives were distributed in 68 families and the naturalized and cultivated in 28 families. Asteraceae, Poaceae y Fabaceae were the richest in both native and naturalized species. The native species were distributed in 146 genera and non natives in 89. Alstroemeria, Baccharis and Calceolaria were the richest in native species; Erodium, Trifolium, Rumex and Vicia, were rich in alien species. Hemicryptophytes and therophytes were most abundant in natives and naturalized species. We conclude that due to increasing urban and agricultural pressures on soils in Province Valparaíso, it is expected that short-lived alien species with opportunistic, high-reproductive capacity, will increase in diversity and abundance. Source


Gonzalez P.A.,Central University of Chile | Gonzalez P.A.,Diego Portales University | Saavedra J.,Pontifical Catholic University of Valparaiso | Vasquez Y.,University of the Frontier
International Journal of Modern Physics D | Year: 2012

We study the Lifshitz black hole in four dimensions with dynamical exponent z = 2 and we calculate analytically the quasinormal modes of scalar perturbations. These quasinormal modes allow to study the stability of the Lifshitz black hole and we have obtained that Lifshitz black hole is stable. © 2012 World Scientific Publishing Company. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Communications in Computer and Information Science | Year: 2015

To solve many problems modeled as Constraint Satisfaction Problems there are no known efficient algorithms. The specialized literature offers a variety of solvers, which have shown good performance. Nevertheless, despite the efforts of the scientific community in developing new strategies, there is no algorithm that is the best for all possible situations. This paper analyses recent developments of Autonomous Search Constraint Solving Systems. Showing that the design of the most efficient and recent solvers is very close to the Experiential Learning Cycle from organizational psychology. © Springer International Publishing Switzerland 2015. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The design of manufacturing cells is a manufacturing strategy that involves the creation of an optimal design of production plants, whose main objective is to minimize movements and exchange of material between these cells. Optimal solution of large scale manufacturing cell design problems (MCDPs) are often computationally unfeasible and only heuristic and approximate methods are able to handle such problems. Artificial fish swarm algorithm (AFSA) belongs to the swarm intelligence algorithms, which based on population search, are able to solve complex optimization problems. In this paper we present an AFSA-based approach to solve the MCDP by using the classic Boctor’s mathematical model. The obtained results show that the proposed algorithm produces optimal solutions for all the 50 studied instances. © Springer International Publishing Switzerland 2015. Source


Moebis O.,Central University of Chile | Moebis O.,San Sebastian University | Intveen H.,San Sebastian University | Intveen H.,University of Concepcion | Vilches V.,University of Concepcion
AUS | Year: 2013

The current Lago Ranco promenade will be expanded and improved through a delicate intervention that takes into account the city's human scale, by using the consolidated trails and spaces gained; keeping existing spatiality and a use approach to the place. It is thought as a useful stroll with identity, to be inhabited with equity. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The Set Covering Problem (SCP) is a representation of a kind of combinatorial optimization problem which has been applied in several problems in the real world. In this work we used a binary version of Teaching-Learning-Based Optimization (TLBO) algorithm to solve SCP, works with two phases known: teacher and learner; emulating the behavior into a classroom. The proposed algorithm has been tested on 65 benchmark instances. The results show that it has the ability to produce solutions competitively. © Springer International Publishing Switzerland 2015. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 9 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The Set Covering Problem (SCP) is a well known NP-hard problem with many practical applications. In this work binary fruit fly optimization algorithms (bFFOA) were used to solve this problem using different binarization methods. The bFFOA is based on the food finding behavior of the fruit flies using osphresis and vision. The experimental results show the effectiveness of our algorithms producing competitive results when solve the benchmarks of SCP from the OR-Library. © Springer International Publishing Switzerland 2015. Source


Ronse De Craene L.,Royal Botanic Garden Edinburgh | Bull-Herenu K.,University of Santiago de Chile | Bull-Herenu K.,Central University of Chile
Annals of Botany | Year: 2016

Background and Aims Obdiplostemony has long been a controversial condition as it diverges from diplostemony found among most core eudicot orders by the more external insertion of the alternisepalous stamens. In this paper we review the definition and occurrence of obdiplostemony, and analyse how the condition has impacted on floral diversification and species evolution. Key Results Obdiplostemony represents an amalgamation of at least five different floral developmental pathways, all of them leading to the external positioning of the alternisepalous stamen whorl within a two-whorled androecium. In secondary obdiplostemony the antesepalous stamens arise before the alternisepalous stamens. The position of alternisepalous stamens at maturity is more external due to subtle shifts of stamens linked to a weakening of the alternisepalous sector including stamen and petal (type I), alternisepalous stamens arising de facto externally of antesepalous stamens (type II) or alternisepalous stamens shifting outside due to the sterilization of antesepalous stamens (type III: Sapotaceae). In primary obdiplostemony the alternisepalous stamens arise before the antesepalous stamens and are more externally from initiation. The antesepalous stamen whorl is staminodial and shows a tendency for loss (type I), or the petals are missing and the alternisepalous stamens effectively occupy their space (type II). Although obdiplostemony is often related to an isomerous gynoecium, this is not essential. Phylogenetically, both secondary and primary obdiplostemony can be seen as transitional stages from diplostemony to either haplostemony or obhaplostemony. Obdiplostemony is the consequence of shifts in the balance between the two stamen whorls, affecting either the alternisepalous stamens together with the petals, or the antesepalous stamens. Conclusions We advocate a broad definition of obdiplostemony, to include androecia with incomplete whorls, staminodial whorls, anisomerous gynoecia and an absence of petals. As such, the taxonomic significance of obdiplostemony is transient, although it is a clear illustration of how developmental flexibility is responsible for highly different floral morphs. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. Source


Lorenzetti D.,National institute for astrophysics | Antoniucci S.,National institute for astrophysics | Giannini T.,National institute for astrophysics | Harutyunyan A.,Fundacion Galileo Galilei INAF | And 8 more authors.
Astrophysical Journal | Year: 2015

V1118 Ori is an eruptive variable belonging to the EXor class of pre-main-sequence stars whose episodic outbursts are attributed to disk accretion events. Since 2006, V1118 Ori has been in the longest quiescence stage ever observed between two subsequent outbursts in its recent history. We present near-infrared photometry of V1118 Ori carried out over the last eight years, along with complete spectroscopic coverage from 0.35 to 2.5 μm. Long term sampling of V1118 Ori in quiescence has never been performed, and hence we can benefit from the current circumstance by determining the lowest values (i.e., the zeroes) of the parameters to be used as reference for evaluating the physical changes typical of more active phases. A quiescence mass accretion rate of 1-3 × 10-9 yr-1 can be derived and the difference from previous determinations is discussed. Based on line emission and IR color analysis, a visual extinction of 1-2 mag is consistently derived, confirming that V1118 Ori (at least in quiescence) is a low-extinction T Tauri star with a bolometric luminosity of about 2.1 . An anti-correlation exists between the equivalent width of the emission lines and the underlying continuum. We searched the literature to evaluate whether or not such behavior is a common feature for the whole class. The anti-correlation is clearly recognizable for all of the available EXors in the optical range (Hβ and H lines); however, this is not as evident in the infrared (Paβ and Brγ lines). The observed anti-correlation supports the accretion-driven mechanism as the most likely to account for continuum variations. © 2015. The American Astronomical Society. All rights reserved. Source


Machado S.,Federal University of Rio de Janeiro | Machado S.,Central University of Chile | Machado S.,Federal University of Uberlandia | Machado S.,Physical Activity Neuroscience Laboratory | And 9 more authors.
Eurasian Journal of Medicine | Year: 2013

Neurological and psychiatric disorders are characterized by several disabling symptoms for which effective, mechanism-based treatments remain elusive. Consequently, more advanced non-invasive therapeutic methods are required. A method that may modulate brain activity and be viable for use in clinical practice is repetitive transcranial magnetic stimulation (rTMS). It is a non-invasive procedure whereby a pulsed magnetic field stimulates electrical activity in the brain. Here, we focus on the basic foundation of rTMS, the main stimulation parametters, the factors that influence individual responses to rTMS and the experimental advances of rTMS that may become a viable clinical application to treat neurological and psychiatric disorders. The findings showed that rTMS can improve some symptoms associated with these conditions and might be useful for promoting cortical plasticity in patients with neurological and psychiatric disorders. However, these changes are transient and it is premature to propose these applications as realistic therapeutic options, even though the rTMS technique has been evidenced as a potential modulator of sensorimotor integration and neuroplasticity. Functional imaging of the region of interest could highlight the capacity of rTMS to bring about plastic changes of the cortical circuitry and hint at future novel clinical interventions. Thus, we recommend that further studies clearly determine the role of rTMS in the treatment of these conditions. Finally, we must remember that however exciting the neurobiological mechanisms might be, the clinical usefulness of rTMS will be determined by its ability to provide patients with neurological and psychiatric disorders with safe, long-lasting and substantial improvements in quality of life. Source


Jerominek M.,Johannes Gutenberg University Mainz | Bull-Herenu K.,Central University of Chile | Bull-Herenu K.,University of Santiago de Chile | Arndt M.,Johannes Gutenberg University Mainz | Classen-Bockhoff R.,Johannes Gutenberg University Mainz
Frontiers in Plant Science | Year: 2014

Morphogenesis in plants is usually reconstructed by scanning electron microscopy and histology of meristematic structures. These techniques are destructive and require many samples to obtain a consecutive series of states. Unfortunately, using this methodology the absolute timing of growth and complete relative initiation of organs remain obscure. To overcome this limitation, an in vivo observational method based on Epi-Illumination Light Microscopy (ELM) was developed and tested with a male inflorescence meristem (floral unit) of the handkerchief tree Davidia involucrata Baill. (Nyssaceae). We asked whether the most basal flowers of this floral unit arise in a basipetal sequence or, alternatively, are delayed in their development. The growing meristem was observed for 30 days, the longest live observation of a meristem achieved to date. The sequence of primordium initiation indicates a later initiation of the most basal flowers and not earlier or simultaneously as SEM images could suggest. D. involucrata exemplarily shows that live-ELM gives new insights into developmental processes of plants. In addition to morphogenetic questions such as the transition from vegetative to reproductive meristems or the absolute timing of ontogenetic processes, this method may also help to quantify cellular growth processes in the context of molecular physiology and developmental genetics studies. © 2014 Jerominek, Bull-Hereñu, Arndt and Claßen-Bockhoff. Source


Lorenzetti D.,National institute for astrophysics | Antoniucci S.,National institute for astrophysics | Giannini T.,National institute for astrophysics | Li Causi G.,National institute for astrophysics | And 6 more authors.
Astrophysical Journal | Year: 2012

We present the results of a comparison between classical and newly identified EXor based on literature data and aimed at recognizing possible differences or similarities between the categories. Optical and near-IR two-color diagrams, modalities of fluctuations, and derived values of the mass accretion rates are indicative of strong similarities between the two samples. We demonstrate how the difference between the outburst and the quiescence spectral energy distribution of all EXor can be well fitted with a single blackbody, as if an additional thermal component appears during the outbursting phase. Temperatures of this additional component span between 1000 and 4500 K, while the radii of the emitting regions (assumed to be a uniform disk) span between 0.01 and 0.1 AU, sizes typical of the inner portions of the circumstellar disk. Spots persisting up to 50% of the outburst duration, not exceeding 10% of the stellar surface, and with temperatures compatible with the EXor mass accretion rates, are able to account for both the appearance of the additional thermal component and the dust sublimation in the inner structures of the disk. We also compare the EXor events with the most significant color and magnitude fluctuations of active T Tauri stars finding that (1) burst accretion phenomena should also be important for this latter class and (2) EXor events could be more frequent than those accidentally discovered. A remarkable case is that of the source V2493 Cyg, a T Tauri star recently identified as a strong outbursting object: New optical and near-IR photometric and spectroscopic data are presented in an attempt to clarify its EXor or FUor nature. © 2012. The American Astronomical Society. All rights reserved. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Machine-Part Cell Formation Problems consists in organizing a plant as a set of cells, each one of them processing machines containing the same type of parts. In recent years, different meta-heuristic have been used to solve this problem. This paper addresses the problem of Machine-Part Cell Formation by using the Migrating Birds Optimization algorithm. The computational experiments show that in most of the benchmark problems the results obtained from the proposed approach are better than those obtained by other methods which are reported in the literature. © Springer International Publishing Switzerland 2015. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 9 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The Set Covering Problem (SCP) is a classic problem in combinatorial optimization. SCP has many applications in engineering, including problems involving routing, scheduling, stock cutting, electoral redistricting and others important real life situations. Because of its importance, SCP has attracted attention of many researchers. However, SCP instances are known as complex and generally NP-hard problems. Due to the combinatorial nature of this problem, during the last decades, several metaheuristics have been applied to obtain efficient solutions. This paper presents a metaheuristics comparison for the SCP. Three recent nature-inspired metaheuristics are considered: Shuffled Frog Leaping, Firefly and Fruit Fly algorithms. The results show that they can obtainn optimal or close to optimal solutions at low computational cost. © Springer International Publishing Switzerland 2015. Source


Besides laying and dividing into lots, the construction of two small-scale public buildings are also part of this case of conversion of rural land to urban use. They stand in the edge of two ravines and serve both as entrance to reserve areas and as orientation devices. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Computational Intelligence and Neuroscience | Year: 2015

The Sudoku problem is a well-known logic-based puzzle of combinatorial number-placement. It consists in filling a n2 × n2 grid, composed of n columns, n rows, and n subgrids, each one containing distinct integers from 1 to n2. Such a puzzle belongs to the NP-complete collection of problems, to which there exist diverse exact and approximate methods able to solve it. In this paper, we propose a new hybrid algorithm that smartly combines a classic tabu search procedure with the alldifferent global constraint from the constraint programming world. The alldifferent constraint is known to be efficient for domain filtering in the presence of constraints that must be pairwise different, which are exactly the kind of constraints that Sudokus own. This ability clearly alleviates the work of the tabu search, resulting in a faster and more robust approach for solving Sudokus. We illustrate interesting experimental results where our proposed algorithm outperforms the best results previously reported by hybrids and approximate methods. © 2015 Ricardo Soto et al. Source


Bull-Herenu K.,University of Santiago de Chile | Bull-Herenu K.,Central University of Chile | Ronse De Craene L.,Royal Botanic Garden Edinburgh | Perez F.,University of Santiago de Chile
Flora: Morphology, Distribution, Functional Ecology of Plants | Year: 2016

Heterostylous species present at least two flower morphs: one is 'long-styled' with a gynoecium overtopping the anthers, and another 'short-styled', presenting the stigma below the anther level. This study investigates how both morphotypes arise through ontogeny using Oxalis cinerea Zucc. and Oxalis rosea Jacq. as study models. We found that long-styled flowers originate from comparatively larger floral meristems that allocate a broader meristematic area to gynoecium inception. Hence long-styled young flowers possess an overall larger size than short-styled ones with a broader and slow-maturing gynoecium. When the flower bud is about 1. mm in diameter, the stylodia overtop the long anthers attaining the typical long-styled configuration. Flower meristematic size appears to be a key determining aspect in the evolution of floral heterostylous morphotypes, playing a role in growth behaviour of the gynoecium. © 2016. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 9 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The set covering problem is a classical model in the subject of combinatorial optimization for service allocation, that consists in finding a set of solutions for covering a range of needs at the lowest possible cost. In this paper, we report various approximate methods to solve this problem, such as Cuckoo Search, Bee Colony, Firefly Optimization, and Electromagnetism-Like Algorithms. We illustrate experimental results of these metaheuristics for solving a set of 65 non-unicost set covering problems from the Beasley’s OR-Library. © Springer International Publishing Switzerland 2015. Source


Chamorro Oschilewsky R.,Central University of Chile
Vertex (Buenos Aires, Argentina) | Year: 2011

Executive control processes, such as sustained attention, response inhibition and working memory allows us to guide behavior appropriately, flexible and adaptable. The consequences of executive dysfunction in humans can be dramatic, as evidenced by the wide range of neurological and neuropsychiatric disorders in which such deficits impact negatively on the performance and quality of life, affecting high prosecutions relating to the prefrontal areas and their connections, including cognitive function. This review is to update and highlight the importance of assess neuropsychological and neurocognitive functional changes that occur in the course of various neuropsychiatric disorders in children and adolescents. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 8 more authors.
Tehnicki Vjesnik | Year: 2015

This paper introduces a proposal of design of Ant Colony Optimization algorithm paradigm using Hyper-Cube framework to solve the Software Project Scheduling Problem. This NP-hard problem consists in assigning tasks to employees in order to minimize the project duration and its overall cost. This assignment must satisfy the problem constraints and precedence between tasks. The approach presented here employs the Hyper-Cube framework in order to establish an explicitly multidimensional space to control the ant behaviour. This allows us to autonomously handle the exploration of the search space with the aim of reaching encouraging solutions. © 2015, Strojarski Facultet. All rights reserved. Source


Soares-Filho G.L.F.,Federal University of Rio de Janeiro | Soares-Filho G.L.F.,Severino Sombra University | Machado S.,Federal University of Rio de Janeiro | Machado S.,Salgado de Oliveira University | And 9 more authors.
American Journal of Cardiology | Year: 2014

Chest pain is often seen alongside with panic attacks. Moreover, panic disorder has been suggested as a risk factor for cardiovascular disease and even a trigger for acute coronary syndrome. Patients with coronary artery disease may have myocardial ischemia in response to mental stress, in which panic attack is a strong component, by an increase in coronary vasomotor tone or sympathetic hyperactivity setting off an increase in myocardial oxygen consumption. Indeed, coronary artery spasm was presumed to be present in cases of cardiac ischemia linked to panic disorder. These findings correlating panic disorder with coronary artery disease lead us to raise questions about the favorable prognosis of chest pain in panic attack. To investigate whether myocardial ischemia is the genesis of chest pain in panic attacks, we developed a myocardial perfusion study through research by myocardial scintigraphy in patients with panic attacks induced in the laboratory by inhalation of 35% carbon dioxide. In conclusion, from the data obtained, some hypotheses are discussed from the viewpoint of endothelial dysfunction and microvascular disease present in mental stress response. © 2014 Elsevier Inc. All rights reserved. Source


Marques L.R.,Polytechnic University of Mozambique | Plaza G.A.,Central University of Chile
Proceedings - 28th International PLEA Conference on Sustainable Architecture + Urban Design: Opportunities, Limits and Needs - Towards an Environmentally Responsible Architecture, PLEA 2012 | Year: 2012

Currently, the city of Santiago de Chile represents an example of the rapid and expansive development experienced by capitals of developing countries. If Santiagós urban model should be classified, the balance tips towards the dispersed city model, characterized by consuming large amounts of resources faster than it can produce them. This paper explores the possible implementation strategies of urban agriculture in Santiago de Chile, related to urban policies and regulations. Urban agriculture is part of the toolkit that enable sustainable social and environmental growth, as well as ecological rehabilitation of cities. Source


Juan Pedro Sepulveda R.,Diego Portales University | Juan Pedro Sepulveda R.,Central University of Chile
Revista Medica de Chile | Year: 2012

Background: Outpatient scheduling has a significant impact on the perceived quality of service by the users and the efficient use of resources in the health system. There are mathematical methods that assist in solving this problem, but are seldom applied. Aim: To propose decision rules that are based on the own conditions of each institution and indicate which appointment system is the most suitable for the decision makers. Material and Methods: Through computer simulation, the effect of a wide range of decision and environmental factors over the appointment systems performance was assessed, in order to determine how these factors affect them. Results: Considering performance indicators associated to the patient's satisfaction and resources utilization, scheduling shorter length patients (e.g. check-up patients) in the beginning of the working day resulted to be in the efficient solutions frontier, as well as scheduling patients in one person blocks (shifting to multiple patient blocks only if resources utilization indicators are prioritized). Conclusions: Performance indicators are more sensitive to the sequence used to schedule different length patients, rather than the number of patients scheduled per block. Moreover, decision rules based on the institution priorities are proposed, which are quite robust to environmental factors. Source


Fernandez H.W.,Central University of Chile | Fernandez H.W.,Polytechnic University of Catalonia | Fernandez H.W.,University of Los Lagos
AUS | Year: 2014

Osorno is the setting of a major patrimonial single-family housing quarter which combines expressions established in the second half of the nineteenth century -mostly the work of Central European settlers- and other expressions emerged as part of modernization processes that took place in the city and its surrounding areas, built from the third to the seventh decade of the twentieth century. This wealth of diverse architectures is a singular and hybrid constructed evidence that admits merger and dialogue, but also the expression of differences, in this case, the tradition-modernity tension. The paper seeks to reveal the continuity and change vectors that are part of such tension and observe its current expressions in these dwellings. This specific housing quarter, given its visibility and effectiveness, helps preserve the historic memory supporting the construction of local identity. Source


Lattari E.,Federal University of Rio de Janeiro | Monteiro-Junior R.S.,Brazilian Institute of Rehabilitation Medicine | Monteiro-Junior R.S.,Iguacu University | Mello Portugal E.M.,Federal University of Rio de Janeiro | And 8 more authors.
International Archives of Medicine | Year: 2014

This systematic review aims to provide information about the implications of the movement-related cortical potential (MRCP) in acute and chronic responses to the counter resistance training. The structuring of the methods of this study followed the proposals of the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses). It was performed an electronically search in Pubmed/Medline and ISI Web of Knowledge data bases, from 1987 to 2013, besides the manual search in the selected references. The following terms were used: Bereitschaftspotential, MRCP, strength and force. The logical operator "AND" was used to combine descriptors and terms used to search publications. At the end, 11 studies attended all the eligibility criteria and the results demonstrated that the behavior of MRCP is altered because of different factors such as: force level, rate of force development, fatigue induced by exercise, and the specific phase of muscular action, leading to an increase in the amplitude in eccentric actions compared to concentric actions, in acute effects. The long-term adaptations demonstrated that the counter resistance training provokes an attenuation in the amplitude in areas related to the movement, which may be caused by neural adaptation occurred in the motor cortex. © 2014Lattari et al.; licensee BioMed Central Ltd. ©2014 Muradov et al.; licensee BioMed Central Ltd. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The non-unicost set covering problem is a classical optimization benchmark that belongs to the Karp’s 21 NP-complete problems. In this paper, we present a new approach based on cuckoo search for solving such problem. Cuckoo search is a modern nature-inspired metaheuristic that has attracted much attention due to its rapid convergence and easy implementation. We illustrate interesting experimental results where the proposed cuckoo search algorithm reaches several global optimums for the non-unicost instances from the OR-Library. © Springer International Publishing Switzerland 2015 Source


Gonzalez P.A.,Central University of Chile | Gonzalez P.A.,Diego Portales University | Saridakis E.N.,Baylor University | Vasquez Y.,University of the Frontier
Journal of High Energy Physics | Year: 2012

We present teleparallel 3D gravity and we extract circularly symmetric solutions, showing that they coincide with the BTZ and Deser-de-Sitter solutions of standard 3D gravity. However, extending into f(T) 3D gravity, that is considering arbitrary functions of the torsion scalar in the action, we obtain BTZ-like and Deser-de-Sitter-like solutions, corresponding to an effective cosmological constant, without any requirement of the sign of the initial cosmological constant. Finally, extending our analysis incorporating the electromagnetic sector, we show that Maxwell-f(T) gravity accepts deformed charged BTZ-like solutions. Interestingly enough, the deformation in this case brings qualitatively novel terms, contrary to the pure gravitational solutions where the deformation is expressed only through changes in the coefficients. We investigate the singularities and the horizons of the new solutions, and amongst others we show that the cosmic censorship can be violated. Such novel behaviors reveal the new features that the f(T) structure brings in 3D gravity. © SISSA 2012. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Constraint programming allows to solve constraint satisfaction and optimization problems by building and then exploring a search tree of potential solutions. Potential solutions are generated by firstly selecting a variable and then a value from the given problem. The enumeration strategy is responsible for selecting the order in which those variables and values are selected to produce a potential solution. There exist different ways to perform this selection, and depending on the quality of this decision, the efficiency of the solving process may dramatically vary. A modern idea to handle this concern, is to interleave during solving time a set of different strategies instead of using a single one. The strategies are evaluated according to process indicators in order to use the most promising one on each part of the search process. This process is known as online control of enumeration strategies and its correct configuration can be seen itself as an optimization problem. In this paper, we present a new system for online control of enumeration strategies based on bat-inspired optimization. The bat algorithm is a relatively modern metaheuristic based on the location behavior of bats that employ echoes to identify the objects in their surrounding area. We illustrate, promising results where the proposed bat algorithm is able to outperform previously reported metaheuristic-based approaches for online control of enumeration strategies. © Springer International Publishing Switzerland 2015 Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Finis Terrae University | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

In this paper we design and evaluate a shuffled frog leaping algorithm that solves the set covering problem. The shuffled frog leaping algorithm is a novel metaheuristic inspired by natural memetics. It consists of an individual memetic evolution and a global memetic information exchange between a population of virtual frogs representing possible solutions of a problem at hand. The experimental results show the effectiveness of our approach which produces competitive results solving a portfolio of set covering problems from the OR-Library. © Springer International Publishing Switzerland 2015. Source


Pulgar J.,Andres Bello University | Poblete E.,Andres Bello University | Alvarez M.,Andres Bello University | Morales J.P.,Andres Bello University | And 3 more authors.
Journal of Fish Biology | Year: 2013

For intertidal fishes belonging to three species, the herbivore Scartichthys viridis (Blenniidae), the omnivore Girella laevifrons (Kyphosidae) and the carnivore Graus nigra (Kyphosidae), mass and body size relationships were higher in individuals from an upwelling zone compared with those from a non-upwelling zone. RNA:DNA were higher in the herbivores and omnivores from the upwelling zone. Higher biomass and RNA:DNA in the upwelling intertidal fishes may be a consequence of an increased exposure to higher nutrient availability, suggesting that increased physiological conditioning in vertebrates from upwelling areas can be detected and measured using intertidal fishes of different trophic levels. © 2013 The Fisheries Society of the British Isles. Source


Misra S.,Pontifical Catholic University of Valparaiso | Fernandez-Sanz L.,Finis Terrae University | Adewumi A.,Pontifical Catholic University of Valparaiso | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Communications in Computer and Information Science | Year: 2015

Complexity metrics are useful for predicting the quality of software systems because they quantify the quality attributes. Web services, a new kind of software system has been providing a common standard mechanism for interoperable integration of disparate systems and gaining a great deal of acceptance by different types of parties that are connected to the internet for different purposes. In this respect, quality of the web-services should be quantified for easy maintenance and quality of services. Further, the Web Services Description Language (WSDL) forms the basis for Web Services. In this paper, we are evaluating the quality of the WSDL documents by applying the Cyclomatic Complexity metric, a well known and effective complexity metric, which has not been used to evaluate the quality of WSDL till date. © Springer-Verlag Berlin Heidelberg 2015. Source


Brihaye Y.,University of Mons | Cisterna A.,Austral University of Chile | Cisterna A.,Central University of Chile | Erices C.,University of Concepcion
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

This paper is concerned with the construction and analysis of boson stars in the context of nonminimal derivative coupling theories. In particular, we embed our model in the biscalar extension of Horndeski gravity, considering a scalar field theory displaying a nonminimally coupled kinetic term given by the Einstein tensor. We focus on the case where the potential is given by a mass term only and when a six order self-interaction is included. In the latter case we consider specific couplings in the self-interacting terms in such a way that our self-interaction is given by a positive definite potential presenting two degenerate local vacua. We show how solutions can be obtained and we compare its principal properties with standard configurations constructed with the usual minimally coupled kinetic term. © 2016 American Physical Society. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The Set Covering Problem is a formal model for many practical optimization problems. It consists in finding a subset of columns in a zero–one matrix such that they cover all the rows of the matrix at a minimum cost. To solve the Set Covering Problem we use a metaheuristic called Binary Cat Swarm Optimization. This metaheuristic is a binary version of Cat Swarm Optimization generated by observing cat behavior. Cats have two modes of behavior: seeking mode and tracing mode. We are the first ones to use this metaheuristic to solve the Set Covering Problem, for this the proposed algorithm has been tested on 65 benchmarks instances. © Springer International Publishing Switzerland 2015. Source


Contreras T.E.,Pontifical Catholic University of Valparaiso | Figueroa J.A.,Pontifical Catholic University of Valparaiso | Figueroa J.A.,University of Santiago de Chile | Figueroa J.A.,Central University of Chile | And 2 more authors.
Revista Chilena de Historia Natural | Year: 2011

Setting fires is an old practice of land management in the Mediterranean region of central Chile. Fire in the region is currently of predominantly human origin and previously published material suggests that the scheduling of these activities is associated with the spread of naturalized exotic species. Research into the effects of fire on both native and exotic Mediterranean vegetation in central Chile has increased notably over recent years. The objective of our review is to highlight new knowledge in this area of research from the last 30 years and to contribute to systematization and an explicit conceptual model which takes into account the effect of a fire regimen on the spread of exotic plants and the mechanisms involved. We begin with analyses of the fire regimen which is currently observed in one Region of central Chile and a subsequent exploration of the literature to identify the attributes mainly of the germination of seeds which are sensitive to fire and which apply to the exotic species that are abundantly naturalized in central Chile. According to the studies consulted, diverse mechanisms have been described which involve the effect of fire on the spread of exotic plants in central Chile. Life-history traits, tolerance, facilitation, and positive feedback between exotic plants and fire frequency have been mechanisms reported in the literature. Finally, we propose a conceptual model which represents dispersal assisted by humans of exotic species and the spread of species naturalized by the effect of fire regimens, which helps explain the composition and structure of the matorral of central Chile in an early successional state. © Sociedad de Biología de Chile. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 8 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Constraint Programming allows the resolution of complex problems, mainly combinatorial ones. These problems are defined by a set of variables that are subject to a domain of possible values and a set of constraints. The resolution of these problems is carried out by a constraint satisfaction solver which explores a search tree of potential solutions. This exploration is controlled by the enumeration strategy, which is responsible for choosing the order in which variables and values are selected to generate the potential solution. Autonomous Search provides the ability to the solver to self-tune its enumeration strategy in order to select the most appropriate one for each part of the search tree. This self-tuning process is commonly supported by an optimizer which attempts to maximize the quality of the search process, that is, to accelerate the resolution. In this work, we present a new optimizer for self-tuning in constraint programming based on artificial bee colonies. We report encouraging results where our autonomous tuning approach clearly improves the performance of the resolution process. © Springer International Publishing Switzerland 2015. Source


Torres-Perez F.,University of New Mexico | Torres-Perez F.,Central University of Chile | Acuna-Retamar M.,University of New Mexico | Acuna-Retamar M.,University of Chile | And 4 more authors.
Infection, Genetics and Evolution | Year: 2011

Chagas disease is one of the most important vector-borne diseases in Latin America. The disease, caused by the flagellate protozoan Trypanosoma cruzi, is commonly transmitted to humans by Triatoma infestans in South America. Using mitochondrial DNA sequences, we assessed alternative biogeographic scenarios of dispersal of T. infestans using coalescence simulations. We also assessed phylogeographic structure and spatial genetics of T. infestans in Chile. Two major routes of dispersal in southern South America were supported including a dual-origin of T. infestans in Chile. Phylogeographic analyses identified two primary clades with Chilean haplotypes partitioned into either a northern cluster with Peruvian and Bolivian haplotypes or a north-central cluster with Argentinean and Uruguayan haplotypes. The north-central clade is further divided into two subgroups. Domestic and sylvatic T. infestans in central Chile were not segregated in the phylogeographic reconstruction. Spatial genetic analyses show higher distances in northern Chile, congruent with the presence of two divergent lineages of T. infestans. Phylogenetic evidence does not unequivocally support the hypothesized Bolivian origin of T. infestans, so we discuss alternative scenarios. © 2010 Elsevier B.V. Source


Fernandez-Davila V.I.,University of Lima | Lopez Vergara A.F.,Central University of Chile
9th US National and 10th Canadian Conference on Earthquake Engineering 2010, Including Papers from the 4th International Tsunami Symposium | Year: 2010

The requirement of minimum positive reinforcement in critical sections located at ends of beams of multistory moment-resistant frames according to chapter 21 of the committee ACI 318 building code is evaluated with the aim to determine its behavior due to gravitational and seismic nature loads. It is noted that the amount of positive reinforcement has direct relation to the capacity of ductility that reinforced concrete sections have to resist negative moments. However, the positive reinforcement has relation to the levels of incursion in the inelastic range, which are not equally distributed according to the level of floor. In accordance with the Park & Ang's damage indices, there is established a greater structural damage concentrated in the lower floor as the minimum requirement of positive reinforcement is increased. In addition, the total damage is greater in the meantime bigger be the amount of minimum positive reinforcement used. Copyright © (2010) by Earthquake Engineering Research Institute. Source


Molina M.E.,University for Development | Del Rio M.T.,Central University of Chile | Villanueva L.T.,University for Development
Revista Argentina de Clinica Psicologica | Year: 2015

This study approaches human encounter and the meaning construction that it unfolds, from a dialogical and micro-process perspective. Considering Valsiner's proposal (2007) a semiotic approach is taken. A Protocol of Analysis is proposed, which describes indicators that regulate the process. Moments of therapeutic dialogue with mothers of sexually abused children were considered in the study. The analysis describes mechanisms that promote the construction, that constrain and enable meanings in dialogue. The participants derived from the impossibility of action to the generation of alternatives in their lives, expressing inter and intra-individual variability of the signification processes. These intersubjective dynamics make possible self and culture joining in a reciprocal process of influences towards stability and change. © 2015 Fundación AIGLÉ. Source


Machado S.,Federal University of Rio de Janeiro | Machado S.,Salgado de Oliveira University | Machado S.,Federal University of Uberlandia | Machado S.,Central University of Chile | And 17 more authors.
Clinical EEG and Neuroscience | Year: 2014

The P300 event-related potential (EPR) is regarded as a neurophysiological indicator of cognitive processing of a stimulus. However, it is not known whether the P300 is a unitary component recorded on the scalp as a result of the activity of a specific intracerebral structure, or if it represents the sum of underlying components that may reflect the activation of broadly distributed intracerebral structures. The objective of the present experiment was to investigate possible correlations among the source(s) involved in the generation of the P300 and their possible neurocognitive function. The visual-evoked potential (VEP) was elicited by the oddball paradigm and analyzed after employment of sLORETA (standardized low-resolution electromagnetic tomography). The window of the P300 wave encompasses the period during which the response to the target and nontarget condition differs significantly (≈375 ms to ≈465 ms, with a peak at ≈422.5 ms). The results showed sequential and what appeared to be logical activation patterns of specific structures (specific for the processing of the stimulus used here) after presentation of the target stimulus. The peak of the P300 wave represented activation of the parahippocampal gyrus, which is responsible for upgrading memory in response to a target stimulus. © EEG and Clinical Neuroscience Society (ECNS) 2014. Source


Oschilewsky R.C.,Central University of Chile | Oschilewsky R.C.,University of Moron | Gomez C.M.,University of Habana | Belfort E.,Central University of Venezuela
International Review of Psychiatry | Year: 2010

The review of epidemiological studies of psychiatric disorders in children and teenagers in Latin America, is validated and updated in this article. The present article incorporates variants that are contributed from the neurosciences, which allow us to see difficulties as opportunities, across such mechanisms as the plasticity neuronal, trying to change paradigms, frequently pessimistic in this type of review, and we call for the active participation of all the scientific societies of our countries in the development of public policies, based on prevention, for the vulnerability of the rights of our children and teenagers suggesting a multidisciplinary boarding in mental health. © 2010 Institute of Psychiatry. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 6 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

The set covering problem belongs to the combinatorial optimization problems, whose complexity is exponential theoretically established as NP-complex problems. Consists in finding a subset of columns in a matrix of zeros and ones such that cover all rows of the matrix at minimal cost. The solution to this problem is presented using, for first time, the binary cat swarm optimization algorithm. This metaheuristic is based on the cat's behavior, where cats have curiosity by objects in motion and have a great hunting ability. Cats have two modes of behavior: seeking mode and tracing mode. The algorithm is tested on 65 instances, which are compared in a result table including a column with the relative percentage deviation. © 2015 AISTI. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Finis Terrae University | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The scheduling problems are very common in any industry or organization. The software project management is frequently faced with different scheduling problems.We present the Resource-Constrained Project Scheduling problem as a generic problem in which different resources must be assigned to different activities, so that the make span is minimized and a set of precedence constraints between activities and resource allocation to these activities are met. This Problem is a NPhard combinatorial optimization problem. In this paper we present the model the resolution of the problem through the Artificial Bee Colony algorithm. The Artificial Bee Colony is a metaheuristic that uses foraging behavior of honey bees for solving problems, especially applied to combinatorial optimization. We present an Artificial Bee Colony algorithm able to solve the Resource-Constrained Project Scheduling efficiently. © Springer International Publishing Switzerland 2015. Source


Segura D.M.,Central University of Chile | Abde K.B.,University of Valparaiso
Revista INVI | Year: 2014

This paper focuses on the territorial experience of foreign migrants and local residents in neighborhoods located in the municipality of Santiago. It is also proposed that, from the perspective of the characteristics of the territory, such an experience constitutes a reality that constantly makes reference to the social structure and the cultural codes of those living in these spaces, thus giving rise to different feelings, images and reactions which are attached to the new immigrant neighbors. In this context, coexistence, exchanges and the arrival of immigrants coming from different places have shaped a heterogeneous urban landscape in which social, political and cultural inequalities have, in turn, led to the unequal distribution of land, and thus the emergence of a new expression of urban vulnerability and a new type of fractured and polarized city. A qualitative approach to territories, neighborhoods and neighbors (both locals and immigrants) in the municipality of Santiago showed that the concentration of immigrant population affects the relationship with territoriality in local/neighborhood spaces and the quality of life of those living in these areas. © 2014 Instituto de la Vivienda. All rights reserved. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 6 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

The Set Covering Problem (SCP) is a representation of a kind of combinatorial optimization problem which has been applied in several problems in the real world. In this work is used the binary version of Teaching-Learning-Based Optimization algorithm (TLBO), which works with two phases known as teacher and learner phases in this way emulates the behaviour into a classroom, besides this problem is solved with eight different transfer functions and five discretization methods all of them altogether to solve The Set Covering Problem from the OR-Library. © 2015 AISTI. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Finis Terrae University | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 8 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

Many practical applications are used in set covering problems (SCP), in this research, we used to solve SCP: the binary Fruit Fly Optimization algorithms. This algorithm is divided in four phases: initiation, smell based search local vision based search and global vision based search. The metaheuristic is based by the knowledge from the foraging behavior of fruit-flies in finding food. The algorithm used a probability vector to improve the exploration. The tests were performed with eight different transfer functions and an elitist selection method. The test results show the effectiveness of the algorithm proposed. © 2015 AISTI. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Finis Terrae University | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 8 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

In this paper, we propose a Modified Binary Firefly Algorithm to solve different instances of the Set Covering Problem (SCP). The Set Covering Problem is considered a classic combinatorial optimization problem, belonging to the class NP-hard problem [8] and have many practical applications. In this paper we consider applying Modified Binary Firefly Algorithm supported in eight Transfer Functions and five Discretization Methods that allow us to express the solution of the problem in the binary domain. The different results presented in this paper show that our algorithm is a good alternative at a low cost to solve the SCP. © 2015 AISTI. Source


Vyhmeister E.,University las Fuerzas Armadas sede Latacunga | Vyhmeister E.,University of Arizona | Reyes-Bozo L.,Central University of Chile | Rodriguez-Maecker R.,University las Fuerzas Armadas sede Latacunga | And 3 more authors.
Chemical Engineering Communications | Year: 2016

Surface functionalization of hydrolyzed methyl-silsesquioxane films were performed by treatment of samples with trimethylchlorosilane (TMCS) and methyltrichlorosilane (MTCS) dissolved in supercritical carbon dioxide. Films thicknesses modifications, pore size distributions, hydrophobicity, dielectric constants, and chemical reaction analyses were performed by ellipsometry, ellipsometric porosimetry, goniometry, electrical measurements, and Fourier transform infrared spectroscopy, respectively. As results, the properties of the functionalized films were able to be modified in function of reaction conditions (concentration, temperature, and/or pressure). Layers thicker than a monolayer were deposited by both TMCS and MTCS, and a tradeoff between the surface functionalization and layer thickness for both chemicals was observed. The results led to the conclusion that a combination of reagents or processing steps could be used for surface properties tuning. © 2016, Copyright © Taylor & Francis Group, LLC. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Finis Terrae University | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 8 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

This paper presents metaheuristic Shuffled Frog Leaping Algorithm (SFLA) to solve the Set Covering Problem (SCP), the SFLA is inspired by the social behavior of frogs, and is being applied to solve many optimization problems. The proposed algorithm includes eight binarization functions and discretization method for resolving the binary representation of the SCP. In the 65 instances of SCP we obtains very promising results. © 2015 AISTI. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 6 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

In the present paper, we resolve the Set Covering Problem using the recently presented meta-heuristic named Binary Bat Algorithm. We use two variations of this algorithm. The Binary Bat Algorithm algorithm was created observing how the bats evade obstacles and find preys to eat, the use of echo-localization is how they do it. We made some changes using two different transfer and two discretization techniques to solve the problem. © 2015 AISTI. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Galleguillos C.,Pontifical Catholic University of Valparaiso | And 5 more authors.
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015 | Year: 2015

The aim of the Sudoku puzzle is filling with digits from 1 to 9 into each cell of a square matrix with 9 rows and 9 columns, divided into 9 3 × 3 regions, so that each column, row, and region contains have different values. This paper reports recent results for solving Sudokus achieved by combining metaheuristics and AC3 which is a filtering technique coming from the constraint programming domain. © 2015 AISTI. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Constraint Programing is a programming paradigm devoted to the efficient solving of constraint satisfaction problems (CSPs). A CSP is a formal problem representation mainly composed of variables and constraints defining relations among those variables. The resolution process of CSPs is commonly carried out by building and exploring a search tree that holds the possibles solutions. Such a tree is dynamically created by interleaving two different phases: enumeration and propagation. During enumeration, the variables and values are chosen to build the possible solution, while propagation intend to delete the values having no chance to reach a feasible result. Autonomous Search is a new technique that gives the ability to the resolution process to be adaptive by re-configuring its enumeration strategy when poor performances are detected. This technique has exhibited impressive results during the last years. However, such a re-configuration is hard to achieve as parameters are problem-dependent and their best configuration is not stable along the search. In this paper, we introduce an Autonomous Search framework that incorporates a new optimizer based on Cuckoo Search able to efficiently support the re-configuration phase. Our goal is to provide an automated, adaptive, and optimized search system for CSPs. We report encouraging results where our approach clearly improves the performance of previously reported Autonomous Search approaches for CSPs. © Springer International Publishing Switzerland 2015. Source


Ronse De Craene L.,Royal Botanic Garden Edinburgh | Iwamoto A.,Tokyo Gakugei University | Bull-Herenu K.,Central University of Chile | Bull-Herenu K.,University of Santiago de Chile | And 5 more authors.
Taxon | Year: 2014

This paper is a discussion and elaboration of a paper by Prenner & al. (2010), entitled “Floral formulae updated for routine inclusion in formal taxonomic descriptions”. The aim of the Prenner paper was to promote the use of floral formulae in botany and to reach a consensus among botanists for best practice. An important purpose of floral formulae is to induce users to observe and describe flowers accurately. It is proposed that additional information on anther, ovule, style and stigma should be included. Also, only visible organs should be included in a formula and theoretical speculations should be illustrated with floral diagrams, which are complementary to formulae, unless there is good reason to include absent organs. We propose a universal, standardized method to accurately shorthand a description of a flower. The level of detail given in the formula can be highly flexible and depends on the intentions of the user. © International Association for Plant Taxonomy (IAPT) 2014. Source


Lagos C.,Pontifical Catholic University of Valparaiso | Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | And 7 more authors.
Canadian Journal of Electrical and Computer Engineering | Year: 2016

A common problem when performing (meta)heuristic techniques over complex combinatorial optimization problems is parameter tuning. Finding the right parameter values can lead to significant improvements in terms of the best solution objective value found by the heuristic, heuristic reliability, and heuristic convergence, among others. Unfortunately, this is usually a tedious and complicated task if done manually. Furthermore, parameter values usually depend on the problem that is going to be solved. In this paper, we propose a framework that is based on the genetic programming (GP) technique to fine tune a key parameter of the well-known tabu search (TS) algorithm. Several experiments are performed over a set of small instances of the well-known capacitated facility location problem. The results have shown that adjusting the probability of acceptance of the best neighbor ρ in the TS algorithm using GP leads to an average value of the obtained solution that is closer to the optimal solution than the average value obtained by the simple TS algorithm with an a priori selected value for ρ. More importantly, standard deviation of the algorithm is greatly improved by our approach, which makes it much more reliable if time limitations are present. Finally, we confirm that the value of the parameter ρ largely depends on the problem that is attempted to solve. © 2016 IEEE. Source


Hernandez H.,Central University of Chile | Meza L.,University of Santiago de Chile
Revista de la Construccion | Year: 2011

This paper proposes a methodology for energy certification of new houses, based on international experiences and national reality. This method allows the construction of new buildings in Chile approaching international standards for low energy consumption. We propose a model based on obtaining a provisional certificate, on the basis of the determination of the demand and energy consumption of the project. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 7 more authors.
Romanian Journal of Information Science and Technology | Year: 2014

This work presents a study of a new binary coded firefly algorithm. The firefly algorithm is a novel nature-inspired metaheuristic, inspired by the social behavior of fireflies, which is being applied to solve many optimization problems. We test the proposed binary coded firefly algorithm solving the non-unicost set covering problem which is a well-known NP-hard discrete optimization problem with many practical applications. To tackle the mapping from a continuous search space to a discrete search space we use different transfer functions which are investigated in terms of convergence speed and accuracy of results. The experimental results show the effectiveness of our approach where the binary coded firefly algorithm produce competitive results solving a portfolio of set covering problems from the OR-Library. Source


Pulgar J.,Andres Bello University | Alvarez M.,Andres Bello University | Delgadillo A.,Andres Bello University | Herrera I.,Andres Bello University | And 6 more authors.
Journal of the Marine Biological Association of the United Kingdom | Year: 2012

Intertidal organisms have long been considered an ideal system to quantify how physical variations determine differential energy allocations in specimens inhabiting environmental gradients such as exposure to wave action. In habitats with differential intertidal wave exposure (sheltered, Sh; and exposed, E) seasonal gonadal and foot weight variations and their associations with exposure and food availability (algae abundance) were determined in the keyhole limpet Fissurella crassa. Gonadal weight is used as a measure of reproduction allocation whereas foot weight is an indirect indicator of energy allocation to survival. RNA:DNA ratio in limpets obtained from Sh and E habitats during the two different seasons was used as an indicator of biosynthetic capability. Our results indicate that algae abundance in E sites was higher in summer and lower in winter compared to Sh sites. In E sites the muscular foot weight of limpet was higher in summer in contrast to Sh sites where F. crassa muscular foot weight of limpet was higher in winter. Gonadal weight in Sh sites was higher in summer and remained constant in winter; whereas in E sites gonadal weight was lower in summer and higher in winter. RNA:DNA ratios indicate that regardless of intertidal wave exposure, F. crassa showed higher biosynthetic capability in summer. Energetic allocation in animals that inhabit sheltered intertidal habitats would support constant allocation towards reproduction. In contrast, animals that inhabit exposed habitats may favour seasonally reproduction allocation at expense of survival. © Copyright Marine Biological Association of the United Kingdom 2012. Source


Alvarado-Soto L.,Andres Bello University | Ramirez-Tagle R.,Andres Bello University | Ramirez-Tagle R.,Central University of Chile
Oxidation Communications | Year: 2011

Our calculations have shown that a series of the studied monosubstituted phenol derivatives containing substituents with different electronic effects on the ortho-, meta- and para-positions, show a direct relationship between the H-abstraction of the hydroxyl groups and the low values of nucleus-independent chemical shift (ANICS) activity, and these in turn are related to antioxidant activity, hence are in the lowest values of the enthalpy of dissociation, and this is demonstrated by the values of small ANICS. All calculations of bond dissociation enthalpy (BDE) and the criterion of aromaticity (ΔNICS) were calculated using density functional theory (DFT) methods. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Central University of Chile | Crawford B.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Romanian Journal of Information Science and Technology | Year: 2014

A Constraint Satisfaction Problem (CSP) consists in a sequence of variables holding a domain of possible values and relations among these variables called constraints. A meta-CSP can be seen as a metaproblem whose decomposition leads to a set of CSPs. The meta-variables correspond to sub-problems of the original problem, and a meta-constraint is a relation among those meta-variables. Meta-CSPs find many applications in industry, usually in processes that involve time and actions such as the control of a robot, a manufacturing process, or the scheduling of any common activity. In this paper, we introduce the notion of Sequentially Dependent Meta-CSP (SD Meta-CSP), which extends the meta-CSP in order to support applications where a dependency between sub-problems is mandatory. In this case, the meta-CSP is decomposed into a set of sub-problems {Pi, Pi+1, . . . , Pn}, but the instance of the sub-problem Pi+1 sequentially depends on the solution of the sub-problem Pi . In this work we provide a formal definition for the SD Meta-CSPs, a framework to handle it, and we illustrate its applicability to video games. In particular, we model and implement agents as SD Meta-CSPs able to autonomously play two classic games: Ms. Pac-Man and Super Mario Bros. Source


Gonzalez P.A.,Central University of Chile | Gonzalez P.A.,Diego Portales University | Saavedra J.,Pontifical Catholic University of Valparaiso
International Journal of Modern Physics A | Year: 2011

In this paper we study the effects of black hole mass on the absorption cross-section for a massive scalar field propagating in a five-dimensional topological ChernSimons black hole at the low-frequency limit. We consider the two branches of black hole solutions (α = ±1) and we show that, if the mass of black hole increase the absorption cross-section decreases at the zero-frequency limit for the branch α = -1 and for the other branch, α = 1, the behavior is opposite, if the black hole mass increase the absorption cross-section increases. Also we find that beyond a certain frequency value, the mass black hole does not affect the absorption cross-section. © 2011 World Scientific Publishing Company. Source


Burgos H.,Laboratorio Of Biopsicologia | Burgos H.,Central University of Chile | Cofre C.,Laboratorio Of Biopsicologia | Hernandez A.,Laboratorio Of Neurobiologia | And 5 more authors.
Behavioural Brain Research | Year: 2015

Methylphenidate (MPH) is widely used as a "nootropic" agent and in the treatment of disorders of attention, and has been shown to modulate synaptic plasticity in vitro. Here we present in vivo evidence that this MPH-induced metaplasticity can last long after the end of treatment. MPH (0, 0.2, 1 and 5. mg/kg) was administered daily to male rats from postnatal day 42 for 15 days. The animals were tested daily in a radial maze. Long-term potentiation (LTP), a marker of neural plasticity, was induced in vivo in the prefrontal cortex after 2-3. h, 15-18 days or 5 months without treatment. The behavioral performance of the 1. mg/kg group improved, while that of animals that had received 5. mg/kg deteriorated. In the 1 and 5. mg/kg groups LTP induced 2-3. h after the last MPH treatment was twice as large as in the controls. Further, 15-18 days after the last MPH administration, in groups receiving 1 and 5. mg/kg, LTP was about fourfold higher than in controls. However, 5 months later, LTP in the 1. mg/kg group was similar to controls and in the 5. mg/kg group LTP could not be induced at all. No significant changes of LTP were seen in the low-dose group of animals (0.2. mg/kg). Thus, firstly, doses of MPH that improve learning coincide approximately with those that augment LTP. Secondly, MPH-induced increases in LTP can last for several weeks, but these may disappear over longer periods or deteriorate at high doses. © 2015 Elsevier B.V. Source


De Ornelas Maia A.C.C.,Federal University of Rio de Janeiro | De Ornelas Maia A.C.C.,National Institute of Translational Medicine INCT TM | De Azevedo Braga A.,Federal University of Rio de Janeiro | De Azevedo Braga A.,National Institute of Translational Medicine INCT TM | And 12 more authors.
Clinical Practice and Epidemiology in Mental Health | Year: 2013

Background: Diabetes is associates with depression and impairment in Quality of Life (QoL). Objective: The objective is to define the frequencies of depressive and anxiety symptoms in a sample of patients diagnosed with type 1 and 2 diabetes, the amount of impairment of QoL and the weight of depression and anxiety in determining the QoL in such of patients. Methods: A total of 210 patients were divided into two groups (type 1 and type 2). Patients completed the HADS and WHOQoL-bref. Results: Groups showed a high prevalence of anxiety (type 1 = 60%, type 2 = 43.8%) and depression (type 1 = 52.4%, type 2 = 38.1%), both measures were significantly higher (p < 0.05) in diabetes type 1 patients. Type 1 patients also showed a QoL in the overall assessment and the physical, psychological and social relations domains. In both Type 1 and 2 diabetes poor QoL was found associated by anxiety and depression comorbidity. Conclusion: In overall diabetes patients depression and anxiety seems to be a determinant of poor QoL. © Maia et al. Source


Santos V.,Federal University of Rio de Janeiro | Paes F.,Federal University of Rio de Janeiro | Pereira V.,Federal University of Rio de Janeiro | Arias-Carrion O.,Hospital General Dr. Manuel Gea Gonzalez | And 7 more authors.
Clinical Practice and Epidemiology in Mental Health | Year: 2013

The present study aims to conduct a systematic review of the literature by checking the impact of positive emotion in the treatment of depression and on the use of strategies of positive psychology which involves positive emotion to treat and reduce symptoms of depression. For this purpose, we conducted searches in databases ISI Web of Knowledge, PsycINFO and PubMed and found a total of 3400 studies. After inclusion application and exclusion criteria, 28 articles remained, presented and discussed in this study. The studies have important relations between humor and positive emotion as well as a significant improvement in signs and symptoms of depression using differents strategies of positive psychology. Another relevant aspect is the preventative character of the proposed interventions by positive psychology by the fact that increase well-being and produce elements such as resilience and coping resources that reduce the recurrent relapses in the treatment of depression. The strategies of positive psychology, such as increasing positive emotions, develop personal strengths: seeking direction, meaning and engagement for the day-to-day life of the patients, appear as potentially tools for the prophylaxis and treatment of depression, helping to reduce signs and symptoms as well as for prevention of relapses. © Santos et al.; Licensee Bentham Open. Source


Sotoyz R.,Pontifical Catholic University of Valparaiso | Sotoyz R.,Autonomous University of Chile | Sotoyz R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Proceedings - International Conference of the Chilean Computer Science Society, SCCC | Year: 2016

Machine-Part Cell Formation consists on organizing a plant as a set of cells, each one of them processing machines containing different part types. In recent years, different techniques have been used to solve this problem ranging from exact to approximate methods. This paper focuses on solving new instances of this problem for which no optimal value exists by using the classic Boctor's mathematical model. We employ constraint programming as the underlying solving technique illustrating that global optimums are achieved for the whole set of tested instances. © 2015 IEEE. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Proceedings - International Conference of the Chilean Computer Science Society, SCCC | Year: 2016

Constraint Programming (CP) allows to solve constraint satisfaction and optimization problems by building and then exploring a search tree of potential solutions. Potential solutions are generated by firstly selecting a variable and then a value from the given problem, phase known as enumeration. In this context, Autonomous Search (AS) that is a particular case of adaptive systems, enables the problem solver to control and adapt its internal configuration during solving time, based on performance metrics in order to be more efficient. The goal is to provide a mechanism for CP solvers, integrating a component able to evaluate the solving performance process. In particular, we employ a classic decision making method called Choice Function (CF). In this paper, we present an evaluation of different choice functions, based on performance exhibited in a indicators set. The results are promising and show that it is feasible to solve constraint satisfaction problems with this new technique. © 2015 IEEE. Source


Figueroa J.A.,Pontifical Catholic University of Valparaiso | Figueroa J.A.,University of Santiago de Chile | Figueroa J.A.,Central University of Chile | Cabrera H.M.,Pontifical Catholic University of Valparaiso | And 2 more authors.
Tree Physiology | Year: 2010

The aim of this study was to investigate, during the summer of the year 2008, the variation in leaf water and photosynthetic characteristics of Eucryphia cordifolia Cav. (Cunoniaceae) along its broad latitudinal distribution in central south Chile (36° to 42° S). The latitudinal variation in water potential (Ψw), water potential at saturation (Ψπ sat), water potential at the turgor lost point (Ψπ tlp), stomatal density of the leaves, leaf nitrogen concentrations and photosynthetic light response were studied in eight populations. The populations located in the northern region of the distribution of E. cordifolia had the lowest leaf water potential. Osmotic potential at full turgor was highest in the two southernmost populations and gradually decreased towards the northernmost points. Similarly, osmotic potential at zero turgor was the lowest in the northern population. On the contrary, the symplastic water content was lower in the two southernmost populations. The highest net photosynthesis rate was recorded for plants in the populations of intermediate distributions, and it was dependent on the precipitation and temperature gradient. The northern populations, which are subject to the lowest precipitations, showed the lowest stomatal densities, which were tightly linked with stomatal conductance variation. Therefore, the variability of Amax was independent of stomatal density and conductance, so that the northern populations, subject to environments with less water availability, presented higher photosynthetic water use efficiency. Photosynthesis variations were also not associated with changes in leaf water potential or in nitrogen content in E. cordifolia leaves, which did not show any consistent latitudinal or altitudinal trend. In conclusion, the results support our hypothesis that the leaf water relations, stomatal characteristics and photosynthetic rates of the leaf would vary along its latitudinal gradient, helping to explain the ability of E. cordifolia trees to inhabit a broad latitudinal and altitudinal range throughout the central south Chile. © The Author 2010. Published by Oxford University Press. All rights reserved. Source


Vieira R.T.,Federal University of Goais | Caixeta L.,Federal University of Goais | Machado S.,Federal University of Rio de Janeiro | Machado S.,National Institute of Translational Medicine INCT TM | And 9 more authors.
Clinical Practice and Epidemiology in Mental Health | Year: 2013

Presenile Dementia or Early Onset Dementia (EOD) is a public health problem, it differs from Senile Dementia, and encloses a significant number of cases; nevertheless, it is still poorly understood and underdiagnosed. This study aims to review the prevalence and etiology of EOD, comparing EOD with Senile Dementia, as well as to show the main causes of EOD and their prevalence in population and non-population based studies. The computer-supported search used the following databases: Pubmed/Medline, ISI Web of Knowledge and Scielo. The search terms were alcohol-associated dementia, Alzheimer's disease, dementia, Creutzfeldt-jakob disease, dementia with lewy bodies, early onset dementia, frontotemporal lobar degeneration, Huntington's disease, mixed dementia, neurodegenerative disorders, Parkinson's disease dementia, presenile dementia, traumatic brain injury, vascular dementia. Only papers published in English and conducted from 1985 up to 2012 were preferentially reviewed. Neurodegenerative diseases are the most common etiologies seen in EOD. Among the general population, the prevalence of EOD was found to range between 0 to 700 per 100.000 habitants in groups of 25-64 years old, with an increasing incidence with age. The progression of EOD was found to range between 8.3 to 22.8 new cases per 100.000 in those aged under 65 years. Alzheimer's disease (AD) is the major etiology, followed by Vascular Dementia (VaD) and Frontotemporal Lobar Degeneration (FTLD). A larger number of epidemiological studies to elucidate how environmental issues contribute to EOD are necessary, thus, we can collaborate in the planning and prevention of services toward dementia patients. © Vieira et al. Source


Dreyse P.,Federico Santa Maria Technical University | Gonzalez I.,University of Santiago de Chile | Gonzalez I.,Central University of Chile | Cortes-Arriagada D.,Nucleus Millennium Chemical Processes and Catalysis | And 7 more authors.
New Journal of Chemistry | Year: 2016

In the present work we report the synthesis and the electrochemical, photoluminescence and electroluminescence properties of two new Ir(iii) cyclometalated complexes denoted as [Ir(F2ppy)2L1](PF6) and [Ir(F2ppy)2L2](PF6), where F2ppy is 2-(2,4-difluorophenyl)pyridine, L1 is 4,4′-diphenylethyl-2,2′-bipyridine and L2 is 4,4′-bis[2-[4-(1,1-dimethylethoxy)phenyl]ethyl]-2,2′-bipyridine. The photoluminescence spectra in solution for both the complexes are characterized by wavelength emission maxima at around 510 nm and higher quantum yields. In the solid state, the emission spectrum of the complex with L2 is characterized by higher emission intensity than the [Ir(F2ppy)2L1](PF6) complex. This behavior is explained as due to the effect of the more bulky structure of the L2 ligand, which prevents, in a more efficient way compared to the complex with L1, the auto-quenching processes in the solid packing. DFT calculations were performed to understand the photophysical behavior of the complexes, and an excellent agreement between experimental and theoretical data was observed. For the complex with L2, the electronic density of the HOMO is located in the chain and phenyl fragment of this ligand. This behavior is quite different from that expected for a typical Ir(iii) cyclometalated complex, where the electron density of the HOMO is located on the metal (t2g orbitals)/phenyl fragment of the cyclometalating ligand. In spite of these differences, both complexes are good emitters, and in both cases the emission comes from a single T1 emitter state with the contribution of the MLCT and LLCT. In order to get a first approximation of the behavior of these complexes in LEC (light emitting electrochemical cells) applications, the electroluminescence spectra with an applied bias of 12 V were obtained. Both the complexes show yellow-green emissions at around 550 nm, with (0.41, 0.48) and (0.45, 0.48) CIE coordinates for [Ir(F2ppy2)2L1](PF6) and [Ir(F2ppy2)2L2](PF6), respectively. © 2016 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

In this paper, we present a Binary cat swarm optimization for solving the Set covering problem. The Set covering problem is a well-known NP-hard problem with many practical applications, including those involving scheduling, production planning and location problems. Binary cat swarm optimization is a recent swarm metaheuristic technique based on the behaviour of discrete cats. Domestic cats show the ability to hunt and are curious about moving objects. The cats have two modes of behavior: seeking mode and tracing mode. Moreover, eight different transfer functions and five discretization techniques are considered for solving the binary problem. We illustrate this approach with 65 instances of the problem and select the best transfer function and discretization technique to solve this problem. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

This paper describes the Software Project Scheduling Problem (SPSP) as a combinatorial optimization problem. In this problem raises the need for a process to assign a set of resources to tasks for a project in a given time, trying to decrease the duration and cost. The workers are the main resource in the project. We present the design of the resolution model to solve the SPSP using an algorithm of fireflies (Firefly Algorithm, FA). We illustrate the experimental results in order to demonstrate the viability and soundness of our approach. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

Due to the competitiveness of the software industry a more stressful tasks for software project managers allocation of the human resources to the different tasks that perform the project. This is not an easy task and it is necessary that is computationally supported since every day projects are larger and these should be developed in the shortest time and possible costs.We propose to use a constructive metaheuristics called IntelligentWater Drops. In this paper the result are compared with another constructive metaheuristics obtaining promising performance. © Springer International Publishing Switzerland 2016. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

The Manufacturing Cell Design Problem (MCDP) consists in creating an optimal design of production plants, through the creation of cells grouping machines that process parts of a given product. The goal is to reduce costs and increase productivity by minimizing movements and exchange of material between these cells. In this paper, we present a Firefly Algorithm (FA) to tackle this problem. The FA is a recent bio-inspired metaheuristic based on the mating behavior of fireflies that employ its flashing capabilities to communicate with each other or attract potential prey.We incorporate efficient transfer and discretization methods in order to suitable handle the binary domains of the problem. Interesting experimental results are illustrated where several global optimums are reached for a set of 90 well-known MCDP instances. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

Biogeography-Based Optimization Algorithm (BBOA) is a kind of new global optimization algorithm inspired by biogeography. It mimics the migration behavior of animals in nature to solve optimization and engineering problems. In this paper, BBOA for the Set Covering Problem (SCP) is proposed. SCP is a classic combinatorial problem from NP-hard list problems. It consist to find a set of solutions that cover a range of needs at the lowest possible cost following certain constraints. In addition, we provide a new feature for improve performance of BBOA, improving stagnation in local optimum. With this, the experiment results show that BBOA is very good at solving such problems. © Springer International Publishing Switzerland 2016. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

Manufacturing plants are commonly organized in cells containing machines that process different parts of a given product. The Manufacturing Cell Design Problem (MCDP) aims at efficiently organizing the machines into cells in order to increase productivity by minimizing the inter-cell moves of parts. In this paper, we present a new approach based on Invasive Weed Optimization (IWO) for solving such a problem. The IWO algorithm is a recent metaheuristic inspired on the colonization behavior of the invasive weeds in agriculture. IWO represents the solutions as weeds that grow and produce seeds to be randomly dispersed over the search area. We additionally incorporate a binary neighbor operator in order to efficiently handle the binary nature of the problem. The experimental results demonstrate the efficiency of the proposed approach which is able to reach several global optimums for a set of 90 well-known MCDP instances. © Springer International Publishing Switzerland 2016. Source


Reyes V.,Pontifical Catholic University of Valparaiso | Araya I.,Pontifical Catholic University of Valparaiso | Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | And 5 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

In this work we present a beam-search approach applied to the Set Covering Problem. The goal of this problem is to choose a subset of columns of minimal cost covering every row. Beam Search constructs a search tree by using a breadthfirst search strategy, however only a fixed number of nodes are kept and the rest are discarded. Even though original beam search has a deterministic nature, our proposal has some elements that makes it stochastic. This approach has been tested with a well-known set of 45 SCP benchmark instances from OR-Library showing promising results. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Central University of Chile | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

The Set Covering Problem is a formal model for many practical optimization problems. It consists in finding a subset of columns in a zero/one matrix such that they cover all the rows of the matrix at a minimum cost. To solve the Set Covering Problem we will use a metaheuristic called Fireworks Algorithm (FWA) inspired by the fireworks explosion. Through the observation of the way that fireworks explode is much similar to the way that an individual searches the optimal solution in swarm. Fireworks algorithm consists of four parts, i.e., the explosion operator, the mutation operator, the mapping rule and selection strategy. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

The Set Covering Problem (SCP) is a classic problem of combinatorial analytic. This problem consists in to find solutions what cover the needs to lower cost. Those can be services to cities, load balancing in production lines or databanks selections. In this paper,we study the resolution of SCP, through InvasiveWeed Optimization (IWO), in its binary version; Binary InvasiveWeed Optimization (BIWO). IWO, it is to imitate to InvasiveWeed behavior (reproduction and selection natural), through mathematics formulations. Where the best weed has more chance of reproduction. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

The Set Covering Problem is a classic combinatorial problem which is looking for solutions to cover needs on a geographic area. In this paper, we applied new ideas to solve The Set Covering Problem. Intelligent Water Drop is a nature inspired algorithm based on water drops behavior on natural river systems and the events that change the nature of water drop and the river environment. It observes that a river can find an optimum path to its goal. The results of experiments seems to be promising with certain configurations for the instances given by OR-Library J.E. Beasley. In addition an innovation was introduced in the algorithm in order to obtain results. Also a heuristic undesirability chosen is presented in this paper. © Springer International Publishing Switzerland 2016. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,San Sebastian University | Crawford B.,Central University of Chile | Soto R.,Pontifical Catholic University of Valparaiso | And 4 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

In this paper, we study a classical problem in combinatorics and computer science, Set Covering Problem. It is one of Karp’s 21 NP-complete problems, using a new and original metaheuristic, Cat Swarm Optimization. This algorithm imitates the domestic cat through two states: seeking and tracing mode. The OR-Library of Beasley instances were used for the benchmark with additional fitness function, thus the problem was transformed from Mono-objective to Bi-objective. The Cat Swarm Optimization finds a set solution non-dominated based on Pareto concepts, and an external file for storing them. The results are promising for further continue in future work optimizing this problem. © Springer International Publishing Switzerland 2016. Source


Araya I.,Pontifical Catholic University of Valparaiso | Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,University Cientifica del SurLima | And 3 more authors.
Expert Systems with Applications | Year: 2015

Abstract The reliability and increasing performance of search-tree-based interval solvers for solving numerical systems of constraints make them applicable to various expert system domains. Filtering methods are applied in each node of the search tree to reduce the variable domains without the loss of solutions. Current interval-based solvers generally leave it up to the solver designer to decide which set of filtering methods to apply to solve a particular problem. In this work, we propose an adaptive strategy to dynamically determine the set of filtering methods that will be applied in each node of the search tree. Our goal is twofold: first, we want to simplify the task of the solver designer, and second, we believe that an adaptive strategy may improve the average performance of the current state-of-the-art strategies. The proposed adaptive mechanism attempts to avoid calling costly filtering methods when their probability of filtering domains is low. We assume that fruitful filtering occurs in nearby revisions or clusters. Thus, the decision about whether or not to apply a filtering method is based on a cluster detection mechanism. When a cluster is detected, the associated methods are consecutively applied in order to exploit the cluster. Alternately, in zones without clusters, only a cheap method is applied, thus reducing the filtering effort in large portions of the search. We compare our approach with state-of-the-art strategies, demonstrating its effectiveness. © 2015 Elsevier Ltd. Source


Gongora M.,Federal University of Rio de Janeiro | Peressutti C.,Federal University of Rio de Janeiro | Peressutti C.,Institute of Applied Neuroscience IAN | Machado S.,Federal University of Rio de Janeiro | And 11 more authors.
Neurological Sciences | Year: 2013

Spinal cord injury (SCI) is a disease that affects millions of people worldwide, causing a temporary or permanent impairment of neuromotor functions. Mostly associated to traumatic lesions, but also to other forms of disease, the appropriate treatment is still unsure. In this review, several ongoing studies are presented that aim to provide methods of prevention that ensure quality of life, and rehabilitation trends to patients who suffer from this injury. Stem cell research, highlighted in this review, seeks to reduce damage caused to the tissue, as also provide spinal cord regeneration through the application of several types of stem cells. On the other hand, research using brain-computer interface (BCI) technology proposes the development of interfaces based on the interaction of neural networks with artificial tools to restore motor control and full mobility of the injured area. PubMed, MEDLINE and SciELO data basis analyses were performed to identify studies published from 2000 to date, which describe the link between SCI with stem cells and BCI technology. © 2012 Springer-Verlag Italia. Source


Paes F.,Federal University of Rio de Janeiro | Paes F.,National Institute for Translational Medicine INCT TM | Baczynski T.,Federal University of Rio de Janeiro | Novaes F.,Federal University of Rio de Janeiro | And 15 more authors.
Clinical Practice and Epidemiology in Mental Health | Year: 2013

Objectives: Social anxiety disorder (SAD) is a common and debilitating anxiety disorders. However, few studies had been dedicated to the neurobiology underlying SAD until the last decade. Rates of non-responders to standard methods of treatment remain unsatisfactorily high of approximately 25%, including SAD. Advances in our understanding of SAD could lead to new treatment strategies. A potential non invasive therapeutic option is repetitive transcranial magnetic stimulation (rTMS). Thus, we reported two cases of SAD treated with rTMS Methods: The bibliographical search used Pubmed/Medline, ISI Web of Knowledge and Scielo databases. The terms chosen for the search were: anxiety disorders, neuroimaging, repetitive transcranial magnetic stimulation. Results: In most of the studies conducted on anxiety disorders, except SAD, the right prefrontal cortex (PFC), more specifically dorsolateral PFC was stimulated, with marked results when applying high-rTMS compared with studies stimulating the opposite side. However, according to the "valence hypothesis", anxiety disorders might be characterized by an interhemispheric imbalance associated with increased righthemispheric activity. With regard to the two cases treated with rTMS, we found a decrease in BDI, BAI and LSAS scores from baseline to follow-up. Conclusion: We hypothesize that the application of low-rTMS over the right medial PFC (mPFC; the main structure involved in SAD circuitry) combined with high-rTMS over the left mPFC, for at least 4 weeks on consecutive weekdays, may induce a balance in brain activity, opening an attractive therapeutic option for the treatment of SAD. © Paes et al.; Licensee Bentham Open. Source


Figueroa J.A.,Pontifical Catholic University of Valparaiso | Figueroa J.A.,Central University of Chile | Figueroa J.A.,University of Santiago de Chile | Teillier S.,Central University of Chile | And 2 more authors.
Acta Oecologica | Year: 2011

Floristic changes in the Mediterranean region of central Chile brought about by human impact appear to be shared with other climatic regions, although there is a notable absence of empirical studies and available quantitative evidence for the central Chile region. This study examines the cover, richness and composition of native and exotic plant species in a representative area of central Chile. Through floristic characterization of 33 sites sampled using 40 × 40 m plots distributed along transect on which the two farthest sites were separated by 50. km, the floristic richness and cover patterns, as well as the general land use characteristics were evaluated (native matorral, espinal, abandoned farming field, forest plantations, periurban sites, road sites, river bank, and burnt site). We recorded 327 species of plants; 213 species were native and 114 were exotic. The average number of species was heterogeneous in all sites, showing a greater relative native frequency in those sites with a lower level of anthropic intervention. Except for the matorral, the cover of exotic species was greater than that of native species. No relation was found between richness and cover in relation to the different types of land use. The relationship between cover of native and exotic was negative, although for richness did not show relationship. Results show that the exotic species are limited by resources, although they have not completely displaced the native species. The native and exotic floras respond to different spatial distribution patterns, so their presence makes it possible to establish two facts rarely quantified in central Chile: first, that the exotic flora replaces (but does not necessarily displace) the native flora, and second, that at the same time, because of its greater geographic ubiquity and the abundance levels that it achieves, it contributes to the taxonomic and physiognomic homogenization of central Chile. © 2011 Elsevier Masson SAS. Source


Carvallo G.O.,Pontifical Catholic University of Valparaiso | Teillier S.,Central University of Chile | Castro S.A.,University of Santiago de Chile | Castro S.A.,Chilean Center of Nanosciences and Nanotechnology | Figueroa J.A.,Central University of Chile
Austral Ecology | Year: 2014

Phylogenetic properties of communities (phylogenetic diversity and phylogenetic structure) allow for the characterisation of phylogenetic patterns and provide the information necessary to infer mechanisms of species assembly. Because humans have introduced exotic species and modified the physical conditions of landscapes, the phylogenetic properties of communities should change according to the proportion of natives to exotics hosted by sites and to the strength of the conditions that act as habitat filters in human-disturbed habitats. To assess the effects of the introduction of exotic plant species, we characterized the phylogenetic properties of 67 plant communities with different degrees of exotic species dominance in a region of central Chile with a Mediterranean climate. Five indices were used to estimate the phylogenetic properties. The Faith index (FPD), the mean pairwise distance (MPD) and the mean nearest neighbour distance (MNND) were used to estimate phylogenetic diversity, and the nearest relative index (NRI) and the nearest taxon index (NTI) were used as estimators of the phylogenetic structure (the phylogenetic distribution of taxa in a community) of species assemblages. We observed greater phylogenetic diversity of natives versus exotic plants despite the fact that natives accounted for a fewer number of taxa among the studied communities. Second, assemblages exhibited a phylogenetically clustered structure, which is attributable to an over-representation of some families of exotic flora (Asteraceae, Brassicaceae, Fabaceae, Papaveraceae, Poaceae) and suggests habitat filtering processes that could have acted by selecting species with traits that permit adaptation to the harsh conditions of human-disturbed sites. © 2013 Ecological Society of Australia. Source


Crawford B.,Pontifical Catholic University of Valparaiso | Crawford B.,Finis Terrae University | Crawford B.,San Sebastian University | Soto R.,Pontifical Catholic University of Valparaiso | And 8 more authors.
Advances in Intelligent Systems and Computing | Year: 2015

This work proposes Shuffled Frog Leaping Algorithms (SFLAs) to solve Set Covering Problems (SCPs). The proposed algorithms include eight transfer function and five discretization methods in order to solve the binary representation of SCP. Different instances of the SetCovering Problem are solved to test our algorithm showing very promising results. © Springer International Publishing Switzerland 2015. Source


Carvalho D.,Veiga de Almeida University | Teixeira S.,Veiga de Almeida University | Teixeira S.,Federal University of Rio de Janeiro | Lucas M.,Veiga de Almeida University | And 20 more authors.
International Archives of Medicine | Year: 2013

Different treatments for stroke patients have been proposed; among them the mirror therapy and motion imagery lead to functional recovery by providing a cortical reorganization. Up today the basic concepts of the current literature on mirror neurons and the major findings regarding the use of mirror therapy and motor imagery as potential tools to promote reorganization and functional recovery in post-stroke patients. Bibliographic research was conducted based on publications over the past thirteen years written in English in the databases Scielo, Pubmed/MEDLINE, ISI Web of Knowledge. The studies showed how the interaction among vision, proprioception and motor commands promotes the recruitment of mirror neurons, thus providing cortical reorganization and functional recovery of post-stroke patients. We conclude that the experimental advances on Mirror Neurons will bring new rational therapeutic approaches to post-stroke rehabilitation. © 2013 Carvalho et al.; licensee BioMed Central Ltd. Source


Gonzalez P.A.,Central University of Chile | Gonzalez P.A.,Diego Portales University | Moncada F.,University of the Frontier | Vasquez Y.,University of the Frontier
European Physical Journal C | Year: 2012

We study scalar perturbations in the background of a topological Lifshitz black hole in four dimensions. We compute analytically the quasinormal modes and from these modes we show that topological Lifshitz black hole is stable. On the other hand, we compute the reflection and transmission coefficients and the absorption cross section and we show that there is a range of modes with high angular momentum which contributes to the absorption cross section in the low frequency limit. Furthermore, in this limit, we show that the absorption cross section decreases if the scalar field mass increases, for a real scalar field mass. © 2012 Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica. Source


Silva F.,Federal University of Rio de Janeiro | Arias-Carrian O.,German Center for Neurodegenerative Diseases | Teixeira S.,Federal University of Rio de Janeiro | Velasques B.,Federal University of Rio de Janeiro | And 19 more authors.
International Archives of Medicine | Year: 2012

Background: Catching an object is a complex movement that involves not only programming but also effective motor coordination. Such behavior is related to the activation and recruitment of cortical regions that participates in the sensorimotor integration process. This study aimed to elucidate the cortical mechanisms involved in anticipatory actions when performing a task of catching an object in free fall. Methods. Quantitative electroencephalography (qEEG) was recorded using a 20-channel EEG system in 20 healthy right-handed participants performed the catching ball task. We used the EEG coherence analysis to investigate subdivisions of alpha (8-12 Hz) and beta (12-30 Hz) bands, which are related to cognitive processing and sensory-motor integration. Results: Notwithstanding, we found the main effects for the factor block; for alpha-1, coherence decreased from the first to sixth block, and the opposite effect occurred for alpha-2 and beta-2, with coherence increasing along the blocks. Conclusion: It was concluded that to perform successfully our task, which involved anticipatory processes (i.e. feedback mechanisms), subjects exhibited a great involvement of sensory-motor and associative areas, possibly due to organization of information to process visuospatial parameters and further catch the falling object. © 2012 Silva et al; licensee BioMed Central Ltd. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 6 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

The manufacturing Cell Design Problem (MCDP) is a well-known problem for lines of manufacture where the main goal is to minimize the inter-cell moves. To solve the MCDP we employ the Shuffled Frog Leaping Algorithm (SFLA), which is a metaheuristic inspired on the natural memetic features of frogs. The frog tries to leap all over the search space for a better result until the stopping criteria is met. The obtained results are compared with previous approaches of the algorithm to test the real efficiency of our proposed SFLA. The results show that the proposed algorithm produces optimal solutions for all the 50 studied instances. © Springer International Publishing Switzerland 2016. Source


Soto R.,Pontifical Catholic University of Valparaiso | Soto R.,Autonomous University of Chile | Soto R.,Scientific University of the South | Crawford B.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Communications in Computer and Information Science | Year: 2015

This paper highlights the current usability issues when solving Sudoku problems. This problem is a well-known puzzle game which consists in assigning numbers in a game board, commonly of 9 × 9 size. The board of the game is composed of 9 columns, 9 rows and 9 3 × 3 sub-grids; each one containing 9 cells with distinct integers from 1 to 9. A game is completed when all cells have a value assigned, and the previous constraints are satisfied. Some instances are very difficult to solve, to tackle this issue, we have used a filtering technique named Arc Consistency 3 (AC3) from the Constraint Programming domain. This algorithm has revealed which is much related to the strategies employed by users in order to solve the Sudoku instances, but in contrast, this technique is executed in a short time, offering a good resolution guide to the users. In general, filtering techniques make easier solving Sudoku puzzles, providing good information to users for this. © Springer International Publishing Switzerland 2015. Source


Becar R.,Catholic University of Temuco | Gonzalez P.A.,Central University of Chile | Gonzalez P.A.,Diego Portales University
International Journal of Modern Physics D | Year: 2012

We study massive scalar fields and Dirac fields propagating in a five-dimensional dilatonic black hole background. We expose that for both fields the physics can be described by a two-dimensional theory, near the horizon. Then, in this limit, by applying the covariant anomalies method we find the Hawking flux by restoring the gauge invariance and the general coordinate covariance, which coincides with the flux obtained from integrating the Planck distribution for fermions. © 2012 World Scientific Publishing Company. Source


Lucas M.,Federal University of Rio de Janeiro | Lucas M.,Veiga de Almeida University | Chaves F.,Federal University of Rio de Janeiro | Chaves F.,Veiga de Almeida University | And 21 more authors.
International Archives of Medicine | Year: 2013

It is well known that perception and estimation of time are fundamental for the relationship between humans and their environment. However, this temporal information processing is inefficient in patients with Parkinson' disease (PD), resulting in temporal judgment deficits. In general, the pathophysiology of PD has been described as a dysfunction in the basal ganglia, which is a multisensory integration station. Thus, a deficit in the sensorimotor integration process could explain many of the Parkinson symptoms, such as changes in time perception. This physiological distortion may be better understood if we analyze the neurobiological model of interval timing, expressed within the conceptual framework of a traditional information-processing model called "Scalar Expectancy Theory". Therefore, in this review we discuss the pathophysiology and sensorimotor integration process in PD, the theories and neural basic mechanisms involved in temporal processing, and the main clinical findings about the impact of time perception in PD. © 2013 Lucas et al.; licensee BioMed Central Ltd. Source