
Freire, A. S., Moreno, E., & Vielma, J. P. (2012). An integer linear programming approach for bilinear integer programming. Oper. Res. Lett., 40(2), 74–77.
Abstract: We introduce a new Integer Linear Programming (ILP) approach for solving Integer Programming (IP) problems with bilinear objectives and linear constraints. The approach relies on a series of ILP approximations of the bilinear P. We compare this approach with standard linearization techniques on random instances and a set of realworld product bundling problems. (C) 2011 Elsevier B.V. All rights reserved.



Freire, A. S., Moreno, E., & Yushimito, W. F. (2016). A branchandbound algorithm for the maximum capture problem with random utilities. Eur. J. Oper. Res., 252(1), 204–212.
Abstract: The MAXIMUM CAPTURE PROBLEM WITH RANDOM UTILITIES seeks to locate new facilities in a competitive market such that the captured demand of users is maximized, assuming that each individual chooses among all available facilities according to the wellknow a random utility model namely the multinomial logit. The problem is complex mostly due to its integer nonlinear objective function. Currently, the most efficient approaches deal with this complexity by either using a nonlinear programing solver or reformulating the problem into a MixedInteger Linear Programing (MILP) model. In this paper, we show how the best MILP reformulation available in the literature can be strengthened by using tighter coefficients in some inequalities. We also introduce a new branchandbound algorithm based on a greedy approach for solving a relaxation of the original problem. Extensive computational experiments are presented, bench marking the proposed approach with other linear and nonlinear relaxations of the problem. The computational experiments show that our proposed algorithm is competitive with all other methods as there is no method which outperforms the others in all instances. We also show a largescale real instance of the problem, which comes from an application in parkandride facility location, where our proposed branchandbound algorithm was the most effective method for solving this type of problem. (C) 2015 Elsevier B.V. All rights reserved.



Gacitua, M. A., Gonzalez, B., Majone, M., & Aulenta, F. (2014). Boosting the electrocatalytic activity of Desulfovibrio paquesii biocathodes with magnetite nanoparticles. Int. J. Hydrog. Energy, 39(27), 14540–14545.
Abstract: The production of reduced valueadded chemicals and fuels using microorganisms as cheap cathodic electrocatalysts is recently attracting considerable attention. A robust and sustainable production is, however, still greatly hampered by a poor understanding of electron transfer mechanisms to microorganisms and the lack of strategies to improve and manipulate thereof. Here, we investigated the use of electricallyconductive magnetite (Fe3O4) nanoparticles to improve the electrocatalytic activity of a H2producing Desulfovibrio paquesii biocathode. Microbial biocathodes supplemented with a suspension of nanoparticles displayed increased H2 production rates and enhanced stability compared to unamended ones. Cyclic voltammetry confirmed that Faradaic currents involved in microbiallycatalyzed H2 evolution were enhanced by the addition of the nanoparticles. Possibly, nanoparticles improve the extracellular electron path to the microorganisms by creating composite networks comprising of mineral particles and microbial cells. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.



Gacitua, M. A., Munoz, E., & Gonzalez, B. (2018). Bioelectrochemical sulphate reduction on batch reactors: Effect of inoculumtype and applied potential on sulphate consumption and pH. Bioelectrochemistry, 119, 26–32.
Abstract: Microbial electrolysis batch reactor systems were studied employing different conditions, paying attention on the effect that biocathode potential has on pH and system performance, with the overall aim to distinguish sulphate reduction from H2 evolution. Inocula from pure strains (Desulfovibrio paquesii and Desulfobacter halotolerans) were compared to a natural source conditioned inoculum. The natural inoculum possess the potential for sulphate reduction on serum bottles experiments due to the activity of mutualistic bacteria (Sedimentibacter sp. and Bacteroides sp.) that assist sulphatereducing bacterial cells (Desulfovibrio sp.) present in the consortium. Electrochemical batch reactors were monitored at two different potentials (graphitebar cathodes poised at 900 and 400mV versus standard hydrogen electrode) in an attempt to isolate bioelectrochemical sulphate reduction from hydrogen evolution. At 900mV all inocula were able to reduce sulphate with the consortium demonstrating superior performance (SO42 consumption: 25.71 g m(2) day(1)), despite the high alkalinisation of the media. At 400mV only the pure Desulfobacter halotolerans inoculated system was able to reduce sulphate (SO42 consumption: 17.47 g m(2) day(1)) and, in this potential condition, pH elevation was less for all systems, confirming direct (or at least preferential) bioelectrochemical reduction of sulphate over H2 production. (c) 2017 Elsevier B.V. All rights reserved.



GaitanEspitia, J. D., Arias, M. B., Lardies, M. A., & Nespolo, R. F. (2013). Variation in Thermal Sensitivity and Thermal Tolerances in an Invasive Species across a Climatic Gradient: Lessons from the Land Snail Cornu aspersum. PLoS One, 8(8).
Abstract: The ability of organisms to perform at different temperatures could be described by a continuous nonlinear reaction norm (i.e., thermal performance curve, TPC), in which the phenotypic trait value varies as a function of temperature. Almost any shift in the parameters of this performance curve could highlight the direct effect of temperature on organism fitness, providing a powerful framework for testing thermal adaptation hypotheses. Interand intraspecific differences in this performance curve are also reflected in thermal tolerances limits (e. g., critical and lethal limits), influencing the biogeographic patterns of species' distribution. Within this context, here we investigated the intraspecific variation in thermal sensitivities and thermal tolerances in three populations of the invasive snail Cornu aspersum across a geographical gradient, characterized by different climatic conditions. Thus, we examined population differentiation in the TPCs, thermalcoma recovery times, expression of heatshock proteins and standard metabolic rate (i.e., energetic costs of physiological differentiation). We tested two competing hypotheses regarding thermal adaptation (the “hotter is better” and the generalistspecialist tradeoffs). Our results show that the differences in thermal sensitivity among populations of C. aspersum follow a latitudinal pattern, which is likely the result of a combination of thermodynamic constraints (“hotter is better”) and thermal adaptations to their local environments (generalistspecialist tradeoffs). This finding is also consistent with some thermal tolerance indices such as the HeatShock Protein Response and the recovery time from chillcoma. However, mixed responses in the evaluated traits suggest that thermal adaptation in this species is not complete, as we were not able to detect any differences in neither energetic costs of physiological differentiation among populations, nor in the heatcoma recovery.



GaitanEspitia, J. D., Bacigalupe, L. D., Opitz, T., Lagos, N. A., Timmermann, T., & Lardies, M. A. (2014). Geographic variation in thermal physiological performance of the intertidal crab Petrolisthes violaceus along a latitudinal gradient. J. Exp. Biol., 217(24), 4379–4386.
Abstract: Environmental temperature has profound effects on the biological performance and biogeographical distribution of ectothermic species. Variation of this abiotic factor across geographic gradients is expected to produce physiological differentiation and local adaptation of natural populations depending on their thermal tolerances and physiological sensitivities. Here, we studied geographic variation in wholeorganism thermal physiology of seven populations of the porcelain crab Petrolisthes violaceus across a latitudinal gradient of 3000 km, characterized by a cline of thermal conditions. Our study found that populations of P. violaceus show no differences in the limits of their thermal performance curves and demonstrate a negative correlation of their optimal temperatures with latitude. Additionally, our findings show that highlatitude populations of P. violaceus exhibit broader thermal tolerances, which is consistent with the climatic variability hypothesis. Interestingly, under a future scenario of warming oceans, the thermal safety margins of P. violaceus indicate that lower latitude populations can physiologically tolerate the oceanwarming scenarios projected by the IPCC for the end of the twentyfirst century.



Gajardo, A., & Goles, E. (2006). Crossing information in twodimensional Sandpiles. Theor. Comput. Sci., 369(13), 463–469.
Abstract: We prove that in a twodimensional Sandpile automaton, embedded in a regular infinite planar cellular space, it is impossible to cross information, if the bit of information is the presence (or absence) of an avalanche. This proves that it is impossible to embed arbitrary logical circuits in a Sandpile through quiescent configurations. Our result applies also for the nonplanar neighborhood of Moore. Nevertheless, we also show that it is possible to compute logical circuits with a twodimensional Sandpile, if a neighborhood of radius two is used in Z(2); crossing information becomes possible in that case, and we conclude that for this neighborhood the Sandpde is Pcomplete and Turing universal. (c) 2006 Elsevier B.V. All rights reserved.



Galanopoulos, P., Girela, D., & Hernandez, R. (2011). Univalent Functions, VMOA and Related Spaces. J. Geom. Anal., 21(3), 665–682.
Abstract: This paper is concerned mainly with the logarithmic Bloch space B(log) which consists of those functions f which are analytic in the unit disc D and satisfy sup(z<1)(1z) log 1/1z f' (z)<infinity, and the analytic Besov spaces Bp, 1 <= p < infinity. They are all subspaces of the space VMOA. We study the relation between these spaces, paying special attention to the membership of univalent functions in them. We give explicit examples of: A bounded univalent function in U(p>1) B(P) Bp but not in the logarithmic Bloch space. A bounded univalent function in B(log) but not in any of the Besov spaces B(p) with p < 2. We also prove that the situation changes for certain subclasses of univalent functions. Namely, we prove that the convex univalent functions in D which belong to any of the spaces B(0), VMOA, B(p) (1 <= p <= infinity), Blog, or some other related spaces are the same, the bounded ones. We also consider the question of when the logarithm of the derivative, log g', of a univalent function g belongs to Besov spaces. We prove that no condition on the growth of the Schwarzian derivative Sg of g guarantees log g' is an element of B(p). On the other hand, we prove that the condition integral(D) (1z(2))(2p2) Sg(z)(p) d A(z)<infinity implies that log g' is an element of B(p) and that this condition is sharp. We also study the question of finding geometric conditions on the image domain g(D) which imply that log g' lies in Bp. First, we observe that the condition of g( D) being a convex Jordan domain does not imply this. On the other hand, we extend results of Pommerenke and Warschawski, obtaining for every p is an element of (1, infinity), a sharp condition on the smoothness of a Jordan curve Gamma which implies that if g is a conformal mapping from D onto the inner domain of Gamma, then log g' is an element of B(p).



Garcia, J., Pope, C., & Altimiras, F. (2017). A Distributed KMeans Segmentation Algorithm Applied to Lobesia botrana Recognition. Complexity, , 14 pp.
Abstract: Early detection of Lobesia botrana is a primary issue for a proper control of this insect considered as the major pest in grapevine. In this article, we propose a novel method for L. botrana recognition using image data mining based on clustering segmentation with descriptors which consider gray scale values and gradient in each segment. This system allows a 95 percent of L. botrana recognition in nonfully controlled lighting, zoom, and orientation environments. Our image capture application is currently implemented in a mobile application and subsequent segmentation processing is done in the cloud.



GarciaEchauri, S. A., Gidekel, M., GutierrezMoraga, A., Santos, L., & De LeonRodriguez, A. (2011). Isolation and phylogenetic classification of culturable psychrophilic prokaryotes from the Collins glacier in the Antarctica. Folia Microbiol., 56(3), 209–214.
Abstract: Culturable psychrophilic prokaryotes were obtained of samples of glacier sediment, seaside mud, glacier melted ice, and Deschampsia antarctica rhizosphere from Collins glacier, Antarctica. The taxonomic classification was done by a culturedependent molecular approach involving the Amplified Ribosomal DNA Restriction Analysis. Two hundred sixty colonies were successfully isolated and subcultivated under laboratory conditions. The analysis showed a bacterial profile dominated by Betaproteobacteria (35.2%) followed by Gammaproteobacteria (18.5%), Alphaproteobacteria (16.6%), Grampositive with high GC content (13%), CytophagaFlavobacteriumBacteroides (13%) and Grampositive with low GC content (3.7%). Eleven of the isolates have been reported previously and the others microorganisms remain uncharacterized. The isolated microorganisms here could be a potential source for biotechnological products, such as coldactive enzymes and secondary metabolites.



GarciaPapani, F., UribeOpazo, M. A., Leiva, V., & Aykroyd, R. G. (2017). BirnbaumSaunders spatial modelling and diagnostics applied to agricultural engineering data. Stoch. Environ. Res. Risk Assess., 31(1), 105–124.
Abstract: Applications of statistical models to describe spatial dependence in georeferenced data are widespread across many disciplines including the environmental sciences. Most of these applications assume that the data follow a Gaussian distribution. However, in many of them the normality assumption, and even a more general assumption of symmetry, are not appropriate. In nonspatial applications, where the data are unimodal and positively skewed, the BirnbaumSaunders (BS) distribution has excelled. This paper proposes a spatial loglinear model based on the BS distribution. Model parameters are estimated using the maximum likelihood method. Local influence diagnostics are derived to assess the sensitivity of the estimators to perturbations in the response variable. As illustration, the proposed model and its diagnostics are used to analyse a realworld agricultural data set, where the spatial variability of phosphorus concentration in the soil is consideredwhich is extremely important for agricultural management.



Garmendia, M. L., Mondschein, S., Matus, O., Murrugarra, R., & Uauy, R. (2017). Predictors of gestational weight gain among Chilean pregnant women: The Chilean Maternal and Infant Nutrition Cohort study. Health Care Women Int., 38(8), 892–904.
Abstract: We identified factors associated with gestational weight gain (GWG) in 1,654 Chilean pregnant women with fullterm pregnancies. At baseline, we collected information about sociodemographic, gynecoobstetric, anthropometric, and healthcarerelated factors. We found that prepregnancy nutritional body mass index was the most important factor related to GWG above recommendations (overweight: ratio of relative risks [RRR] = 2.31, 95% confidence interval [CI, 1.73, 3.09] and obesity: RRR = 2.90, 95% CI [2.08, 4.03]). We believe that women who are overweight/obese at the beginning of pregnancy should be identified because of their higher risk, and that adequate strategies should be designed and implemented to help them achieve a healthy GWG.



Garreton, M., & Sanchez, R. (2016). Identifying an optimal analysis level in multiscalar regionalization: A study case of social distress in Greater Santiago. Comput. Environ. Urban Syst., 56, 14–24.
Abstract: Assembling spatial units into meaningful clusters is a challenging task, as it must cope with a consequential computational complexity while controlling for the modifiable areal unit problem (MAUP), spatial autocorrelation and attribute multicolinearity. Nevertheless, these effects can reveal significant interactions among diverse spatial phenomena, such as segregation and economic specialization. Various regionalization methods have been developed in order to address these questions, but key fundamental properties of the aggregation of spatial entities are still poorly understood. In particular, due to the lack of an objective stopping rule, the question of determining an optimal number of clusters is yet unresolved. Therefore, we develop a clustering algorithm which is sensitive to scalar variations of multivariate spatial correlations, recalculating PCA scores at several aggregation steps in order to account for differences in the span of autocorrelation effects for diverse variables. With these settings, the scalar evolution of correlation, compactness and isolation measures is compared between empirical and 120 random datasets, using two dissimilarity measures. Remarkably, adjusting several indicators with real and simulated data allows for a clear definition of a stopping rule for spatial hierarchical clustering. Indeed, increasing correlations with scale in random datasets are spurious MAUP effects, so they can be discounted from real data results in order to identify an optimal clustering level, as defined by the maximum of authentic spatial selforganization. This allows singling out the most socially distressed areas in Greater Santiago, thus providing relevant sociospatial insights from their cartographic and statistical analysis. In sum, we develop a useful methodology to improve the fundamental comprehension of spatial interdependence and multiscalar selforganizing phenomena, while linking these questions to relevant real world issues. (c) 2015 Elsevier Ltd. All rights reserved.



Gaspers, S., Liedloff, M., Stein, M., & Suchan, K. (2015). Complexity of splits reconstruction for lowdegree trees. Discret Appl. Math., 180, 89–100.
Abstract: Given a vertexweighted tree T, the split of an edge em T is the minimum over the weights of the two trees obtained by removing e from T, where the weight of a tree is the sum of weights of its vertices. Given a set of weighted vertices V and a multiset of integers s, we consider the problem of constructing a tree on V whose splits correspond to s. The problem is known to be NPcomplete, even when all vertices have unit weight and the maximum vertex degree of T is required to be at most 4. We show that the problem is strongly NPcomplete when T is required to be a path, the problem is NPcomplete when all vertices have unit weight and the maximum degree of T is required to be at most 3, and it remains NPcomplete when all vertices have unit weight and T is required to be a caterpillar with unbounded hair length and maximum degree at most 3. We also design polynomial time algorithms for the variant where T is required to be a path and the number of distinct vertex weights is constant, and the variant where all vertices have unit weight and T has a constant number of leaves. The latter algorithm is not only polynomial when the number of leaves, k, is a constant, but also is a fixedparameter algorithm for parameter k. Finally, we shortly discuss the problem when the vertex weights are not given but can be freely chosen by an algorithm. The considered problem is related to building libraries of chemical compounds used for drug design and discovery. In these inverse problems, the goal is to generate chemical compounds having desired structural properties, as there is a strong relation between structural invariants of the particles, such as the Wiener index and, less directly, the problem under consideration here, and physicochemical properties of the substance. (C) 2014 Elsevier B.V. All rights reserved.



Gazitua, M. C., Slater, A. W., Melo, F., & Gonzalez, B. (2010). Novel alphaketoglutarate dioxygenase tfdArelated genes are found in soil DNA after exposure to phenoxyalkanoic herbicides. Environ. Microbiol., 12(9), 2411–2425.
Abstract: P>Phenoxyalkanoic herbicides such as 2,4dichlorophenoxyacetate (2,4D), 2,4dichlorophenoxybutyrate (2,4DB) or mecoprop are widely used to control broadleaf weeds. Several bacteria have been reported to degrade these herbicides using the alphaketoglutaratedependent, 2,4dichlorophenoxyacetate dioxygenase encoded by the tfdA gene, as the enzyme catalysing the first step in the catabolic pathway. The effects of exposure to different phenoxyalkanoic herbicides in the soil bacterial community and in the tfdA genes diversity were assessed using an agricultural soil exposed to these anthropogenic compounds. Total community bacterial DNA was analysed by terminal restriction fragment length polymorphism of the 16S rRNA and the tfdA gene markers, and detection and cloning of tfdA gene related sequences, using PCR primer pairs. After up to 4 months of herbicide exposure, significant changes in the bacterial community structure were detected in soil microcosms treated with mecoprop, 2,4DB and a mixture of both plus 2,4D. An impressive variety of novel tfdA gene related sequences were found in these soil microcosms, which cluster in new tfdA gene related sequence groups, unequally abundant depending on the specific herbicide used in soil treatment. Structural analysis of the putative protein products showed small but significant amino acid differences. These tfdA gene sequence variants are, probably, required for degradation of natural substrate(s) structurally related to these herbicides and their presence explains selfremediation of soils exposed to phenoxyalkanoic herbicides.



Girard, A., Gago, E. J., Muneer, T., & Caceres, G. (2015). Higher ground source heat pump COP in a residential building through the use of solar thermal collectors. Renew. Energy, 80, 26–39.
Abstract: This article investigates the feasibility of achieving higher performance from groundsource heatpumps (GSHP) in space heating mode through the use of solar thermal collectors. A novel simulation tool for solarassisted groundsource heatpumps (SGSHP) is presented with an analysis of the influence of solar collectors on the improvement of heat pump performance. Solar radiation and climate temperature data of 19 European cities were used to perform simulations of SGSHP and GSHP systems considering a typical residential house. Overall performance coefficients (COPsys) varied from northern to southern locations between 4.4 and 5.8 for SGSHP and between 4.3 and 5.1 for GSHP. Results show that solar collectors coupling has more impact on performance improvement in regions that benefit from higher irradiance. However, greater running cost savings are achieved in milder climate conditions. Both heatpump systems are able to effectively contribute to carbon footprint reductions for residential buildings, especially in countries where fossil fuels are the primary source of electricity generation. SGSHP payback periods are found between 8.5 and 23 years from northern to southern localities, making such heating system an economic heating option. SGSHPs are best suited for high irradiance and cool climate locations such as the mountainous regions in southern Europe. (C) 2015 Elsevier Ltd. All rights reserved.



Girard, A., Gago, E. J., Ordonez, J., & Muneer, T. (2016). Spain's energy outlook: A review of PV potential and energy export. Renew. Energy, 86, 703–715.
Abstract: Spain must reduce its energy consumption by 23% and achieve 100% renewable energy in electricity generation by 2030. This paper presents the current energy scenario en Spain, and the outlooks for different renewable options, with special focus on photovoltaic (PV) solar energy. In 2012, Spain was the number two European country in terms of installed rewnewable energy power. Solar PV technology has the potential to meet Spain's future energy demand and its associated environmental challenges. This paper gives a review of solar energy economy at global scale for both PV and thermal power technologies. The Spanish energy scenario shows actual trends and progress made by solar power. Economic concepts of levelised cost of electricity and grid parity are presented. The financial analysis shows that PV electricity achieves grid parity at a plant profitability rate up to 7.26%. (C) 2015 Elsevier Ltd. All rights reserved.



Girard, A., Muneer, T., & Caceres, G. (2014). A validated design simulation tool for passive solar space heating: Results from a monitored house in West Lothian, Scotland. Indoor Built Environ., 23(3), 353–372.
Abstract: Determining the availability of renewable sources on a particular site would result in increasing the efficiency of buildings through appropriate design. The overall aim of the project is to develop a pioneering software tool allowing the assessment of possible energy sources for any building design project. The package would allow the user to simulate the efficiency of the Passive Solar Space Heating referred in the Low and Zero Carbon Energy Sources (LZCES) Strategic Guide stated by the Office of the Deputy Prime Minister (2006) and the Building Regulations. This research paper presents the tool for modelling the passive solar sources availability in relation to lowcarbon building. A 3month experimental set up monitoring a solar house in West Lothian, Scotland, was also undertaken to validate the simulation tool. Experimental and simulation results were found in good agreement following a onetoone relationship demonstrating the ability of the newly developed tool to assess potential solar gain available for buildings. This modelling tool is highly valuable in consideration of the part L of the Building Regulations (updated in 2010).



Giustinianovich, E. A., Campos, J.  L., & Roeckel, M. D. (2016). The presence of organic matter during autotrophic nitrogen removal: Problem or opportunity? Sep. Purif. Technol., 166, 102–108.
Abstract: Abstract
The simultaneous nitrification, Anammox and denitrification (SNAD) process discovered six years ago is an adaptation of the autotrophic denitrification process that allows for treating nitrogenrich wastewater streams with moderate amounts of organic carbon. Several authors have noted that it is possible to utilize organic carbon to promote nitrogen removal via the action of denitrifying microorganisms, which can remove the remnant nitrate produced by Anammox bacteria. Thus, SNAD systems can achieve nitrogen removal efficiencies higher than 89%, which is what is expected under autotrophic conditions. Three bacterial groups are responsible for SNAD reactions: ammoniumoxidizing bacteria (AOB), anaerobic ammoniumoxidizing bacteria (AnAOB) and heterotrophic bacteria (HB). Because HB will compete with AOB and AnAOB for oxygen and nitrite, respectively, the system should be operated in such way that a balance among the different bacterial populations is achieved. Here, the results reported in the literature are analyzed to define suitable characteristics of effluents for treatment and operational conditions to allow the SNAD process to be carried out with different types of technologies.



Go, R. S., Munoz, F. D., & Watson, J. P. (2016). Assessing the economic value of cooptimized gridscale energy storage investments in supporting high renewable portfolio standards. Appl. Energy, 183, 902–913.
Abstract: Worldwide, environmental regulations such as Renewable Portfolio Standards (RPSs) are being broadly adopted to promote renewable energy investments. With corresponding increases in renewable energy deployments, there is growing interest in gridscale energy storage systems (ESS) to provide the flexibility needed to efficiently deliver renewable power to consumers. Our contribution in this paper is to introduce a unified generation, transmission, and bulk ESS expansion planning model subject to an RPS constraint, formulated as a twostage stochastic mixedinteger linear program (MILP) optimization model, which we then use to study the impact of cooptimization and evaluate the economic interaction between investments in these three asset classes in achieving high renewable penetrations. We present numerical case studies using the 24bus IEEE RTS96 test system considering wind and solar as available renewable energy resources, and demonstrate that up to $180 million/yr in total cost savings can result from the cooptimization of all three assets, relative to a situation in which no ESS investment options are available. Surprisingly, we find that cooptimized bulk ESS investments provide significant economic value through investment deferrals in transmission and generation capacity, but very little savings in operational cost. Finally, we observe that planning transmission and generation infrastructure first and later optimizing ESS investments as is common in industry captures at most 1.7% ($3 million/yr) of the savings that result from cooptimizing all assets simultaneously. (C) 2016 Elsevier Ltd. All rights reserved.

