Abstract: The risk of cracking in a concrete pavement that is opened to traffic at early ages is related to the maximum tensile stress sigma(I), that develops in the pavement and its relationship to the measured, age dependent, flexural strength of a beam,f(r). The stress that develops in the pavement is due to several factors including traffic loading and restrained volume change caused by thermal or hygral variations. The stress that develops is also dependent on the time-dependent mechanical properties, pavement thickness, and subgrade stiffness. There is a strong incentive to open many pavements to traffic as early as possible to allow construction traffic or traffic from the traveling public to use the pavement. However, if the pavement is opened to traffic too early, cracking may occur that may compromise the service life of the pavement. The purpose of this paper is two-fold: (1) to examine the current opening strength requirements for concrete pavements (typically a flexural strength from beams, f(r)) and (2) to propose a criterion based on the time-dependent changes of sigma(I)/f(r), which accounts for pavement thickness and subgrade stiffness without adding unnecessary risk for premature cracking. An accelerated pavement testing (APT) facility was used to test concrete pavements that are opened to traffic at an early age to provide data that can be compared with an analytical model to determine the effective sigma(I)/f(r), based on the relevant features of the concrete pavement, the subgrade, and the traffic load. It is anticipated that this type of opening criteria can help the decision makers in two ways: (1) it can open pavement sections earlier thereby reducing construction time and (2) it may help to minimize the use of materials with overly accelerated strength gain that are suspected to be more susceptible to develop damage at early ages than materials that gain strength more slowly. (C) 2015 Elsevier Ltd. All rights reserved.

Abstract: The SET DOMAIN GROUP (SDG) proteins represent an evolutionarily-conserved family of epigenetic regulators present in eukaryotes and are putative candidates for the catalysis of lysine methylation in histones. Plant genomes analyses of this family have been performed in arabidopsis, maize, and rice and functional studies have shown that SDG genes are involved in the control of plant development. In this work, we describe the identification and structural characterization of SDG genes in the Vitis vinifera genome. This analysis revealed the presence of 33 putative SDG genes that can be grouped into different classes, as it has been previously described for plants. In addition to the SET domain, the proteins identified possessed other domains in the different classes. As part of our study regarding the growth and development of grapevine, we selected eight genes and their expression levels were analyzed in representative vegetative and reproductive organs of this species. The selected genes showed different patterns of expression during inflorescence and fruit development, suggesting that they participate in these processes. Furthermore, we showed that the expression of selected SDGs changes during viral infection, using as a model Grapevine Leafroll Associated Virus 3-infected symptomatic grapevine leaves and fruits. Our results suggest that developmental changes caused by this virus could be the result of alterations in SDG expression.

Abstract: Organizations that make use of computer information systems (CIS) are prototypical complex adaptive systems (CAS). This paper shows how an approach from Complexity Science, exploratory agent-based modeling (ABM), can be used to study the impact of two different modes of use of computer-mediated communication (CMC) on organizational culture (OC) and performance. The ABM includes stylized representations of (a) agents communicating with other agents to complete tasks; (b) an OC consisting of the distribution of agent traits, changing as agents communicate; (c) the effect of OC on communication effectiveness (CE), and (d) the effect of CE on task completion times, that is, performance. If CMC is used in a broad mode, that is, to contact and collaborate with many, new agents, the development of a strong OC is slowed, leading to decreased CE and poorer performance early on. If CMC is used in a local mode, repeatedly contacting the same agents, a strong OC develops rapidly, leading to increased CE and high performance early on. However, if CMC is used in a broad mode over longer time periods, a strong OC can develop over a wider set of agents, leading to an OC that is stronger than an OC which develops with local CMC use. Thus broad use of CMC results in overall CE and performance that is higher than is generated by local use of CMC. We also discuss how the dynamics generated by an ABM can lead to a deeper understanding of the behavior of a CAS, for example, allowing us to better design empirical longitudinal studies.

Abstract: In this paper we study the dynamical behavior of Boolean networks with firing memory, namely Boolean networks whose vertices are updated synchronously depending on their proper Boolean local transition functions so that each vertex remains at its firing state a finite number of steps. We prove in particular that these networks have the same computational power than the classical ones, i.e. any Boolean network with firing memory composed of m vertices can be simulated by a Boolean network by adding vertices. We also prove general results on specific classes of networks. For instance, we show that the existence of at least one delay greater than 1 in disjunctive networks makes such networks have only fixed points as attractors. Moreover, for arbitrary networks composed of two vertices, we characterize the delay phase space, i.e. the delay values such that networks admits limit cycles or fixed points. Finally, we analyze two classical biological models by introducing delays: the model of the immune control of the lambda\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\lambda $$\end{document}-phage and that of the genetic control of the floral morphogenesis of the plant Arabidopsis thaliana.

Abstract: A new general formulation for the spatial modeling of combat is presented, where the main drivers are movement attitudes and struggle evolution. This model in its simplest form is represented by a linear set of two coupled partial differential equations for two independent functions of the space and time variables. Even though the problem has a linear shape, non-negative values for the two functions render this problem as nonlinear. In contrast with other attempts, this model ensures stability and theoretical consistency with the original Lanchester Equations, allowing for a better understanding and interpretation of the spatial modeling. As a numerical illustration a simple combat situation is developed. The model is calibrated to simulate different troop movement tactics that allow an invader force to provoke maximum damage at a minimum cost. The analysis provided here reviews the trade-off between spatial grid and time stepping for attrition cases and then extends it to a new method for guaranteeing good numerical behavior when the solution is expected to grow along the time variable. There is a wide variety of spatial problems that could benefit from this analysis. (C) 2011 Elsevier Ltd. All rights reserved.

Abstract: In this paper, we review the latest developments in biological methods used in the removal of hydrogen sulphide, present in the liquid phase in anaerobic reactors. The toxicity of H2S to methane-forming microorganisms and the problems caused by the presence of this compound in the biogas generated during this process, as well as the main causes of hydrogen sulphide generation in anaerobic processes of wastes are also reviewed. We especially discuss the fundamentals in applying micro-aerobic conditions to remove dissolved hydrogen sulphide from the aqueous phase of an anaerobic reactor. The alternative technology of simultaneous removal of sulphide, nitrate, and organic matter is under recent investigation. Therefore, this review paper includes a study and analysis of the microbiological basis of this technology, the physical and chemical factors that influence the process and the potential application of this technology on different types of wastewaters and situations. Also considered are the fundamentals of both biofilm reactors and microbial fuel cells desulphurization. Because relatively few studies on modeling desulphurisation processes are available, we discuss the advances made in that area.

Abstract: In this paper we consider characterizations of the robust uncertainty sets associated with coherent and distortion risk measures. In this context we show that if we are willing to enforce the coherent or distortion axioms only on random variables that are affine or linear functions of the vector of random parameters, we may consider some new variants of the uncertainty sets determined by the classical characterizations. We also show that in the finite probability case these variants are simple transformations of the classical sets. Finally we present results of computational experiments that suggest that the risk measures associated with these new uncertainty sets can help mitigate estimation errors of the Conditional Value-at-Risk. (C) 2014 Elsevier B.V. All rights reserved.

Abstract: Reducing greenhouse gas emissions and improving energy production sustainability is a paramount of Chile's 2050 energy policy. This though, is difficult to achieve without some degree of nuclear power involvement, given that the geography of the country consists of many areas that are practically off-grid, whereas cannot be developed and financially exploited due to the lack of basic commodities such as water and electricity. Recently small modular reactors (SMRs) have gained lots of attention by both researchers and world policy makers for their promised capabilities of enhanced safety systems, affordable costs and competitive scalability. SMRs can be located in remote areas and at this time are being actively developed in Argentina, USA, Brazil, Russia, China, South Korea, Japan, India and South Africa. Chile's 2010 earthquake and Fukushima's 2011 nuclear disaster have increased significantly both the population's fear and opposition to Nuclear Power Energy for the possible consequences of radiation on the lives of people. This paper aims to study the seismic resistance of a typical nuclear structure, being at time proposed in Small Modular Reactors, by using earthquake conditions typically seen in Chile. Since many designs are under study, a NuScale reactor from USA is analyzed under these extreme loading conditions. The major advantages of the NuScale reactor are in the power scalability (it can go from 1 to 12 reactor cores producing from 60 to 720 MWe), limited nuclear fuel concentration, modules allocated below grade and high strength steel containments fully immersed in water. The cooling effect beyond Design Basis Accident is ensured indefinitely, which induces a significant safety factor in the case of an accident. For the purpose of this study a detailed 3D detailed structural model was developed, reproducing the NuScale reactor's reinforced concrete framing system, where nonlinear analyses was performed to assess the overall mechanical response of the structure. The framing system has been tested under high seismic excitations typically seen in Chile (Mw > 8.0), showing high resistance and capability to cope with the developed forces due to its design. Based on a Soil-Structure Interaction analysis, it was also found that the NuScale framing system manages to maintain a low-stress level at the interaction surface between the foundation and the soil, where the structural system was found to be able to withstand significant earthquake loads. Finally, further investigation is deemed necessary in order to study the potential damages of the structure in the case of other hazards such as tsunami events, blast loads, etc.

Abstract: Some restructured power systems rely on audited cost information instead of competitive bids for the dispatch and pricing of electricity in real time, particularly in hydro systems in Latin America. Audited costs are also substituted for bids in U.S. markets when local market power is demonstrated to be present. Regulators that favor a cost-based design argue that this is more appropriate for systems with a small number of generation firms because it eliminates the possibilities for generators to behave strategically in the spot market, which is a main concern in bid-based markets. We discuss existing results on market power issues in cost- and bid-based designs and present a counterintuitive example, in which forcing spot prices to be equal to marginal costs in a concentrated market can actually yield lower social welfare than under a bid-based market design due to perverse investment incentives. Additionally, we discuss the difficulty of auditing the true opportunity costs of generators in cost- based markets and how this can lead to distorted dispatch schedules and prices, ultimately affecting the long-term economic efficiency of a system. An important example is opportunity costs that diverge from direct fuel costs due to energy or start limits, or other generator constraints. Most of these arise because of physical and financial inflexibilities that become more relevant with increasing shares of variable and unpredictable generation from renewables.