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Facultad de Economía Vasco de Quiroga. Maestría en Gestión Pública de la Sustentabilidad In recent decades the natural resources and cultural diversity of the indigenous peoples and communities of Mexico have become relevant for the tourism industry, which has been favored through economic and tourism policies in our country, increasing new market niches and infrastructure in places to attract visitors, considering that these programs are the best alternative for their development, creation of jobs and improvements in their living conditions. In this study, the results obtained are presented through the identification of the transformations perceived by the inhabitants of the indigenous community of the Janitzio island associated with tourism activity, based on participatory community workshops, promoted by inhabitants, authorities traditional and diverse guilds or trades of the community. These transformations were identified from several dimensions, in a temporality of approximately eighty years of tourism activity in various subjects: 1) in the social dimension: health, alcoholism and drug addiction, education, traditional architecture; 2) in the environmental dimension: extinction of native species, fishing gear techniques, fishing disorder, pollution generated by boats, solid waste, wastewater treatment; 3) in the economic dimension: creation of new trades and economic activities, ambulatory, migration, and elements that give a bad image of the island; 4) cultural dimension: traditional clothing, mother tongue, cultural manifestations, changes in food culture, worldview and indigenous knowledge; and 5) political dimension: civil positions, communal charges and religious positions. Likewise, with the solution alternatives proposed by the inhabitants themselves, the bases were designed for the management of sustainable community development in the indigenous community of the island of Janitzio, based on the application of the Logical Framework Methodology (MML). En las últimas décadas los recursos naturales y la diversidad cultural de los pueblos y comunidades indígenas de México han cobrado relevancia para la industria turística, misma que ha sido favorecida a través de políticas económicas y turísticas de nuestro país, incrementando nuevos nichos de mercado e infraestructura en sitios para atraer visitantes, considerando que estos programas son la mejor alternativa para su desarrollo, creación de empleos y mejoras de sus condiciones de vida. En este estudio, se presentan los resultados obtenidos a través de la identificación de las trasformaciones que perciben los habitantes de la comunidad indígena de la isla Janitzio asociadas a la actividad turística, a partir de la realización de talleres comunitarios participativos, impulsados por habitantes, autoridades tradicionales y diversos gremios u oficios de la comunidad. Estas transformaciones fueron identificadas desde varias dimensiones, en una temporalidad de aproximadamente ochenta años de actividad turística en diversos temas: 1) en la dimensión social: salud, alcoholismo y drogadicción, educación, arquitectura tradicional; 2) en la dimensión ambiental: extinción de especies nativas, técnicas de artes de pesca, desorden pesquero, la contaminación que generan las embarcaciones, residuos sólidos, el tratamiento de aguas residuales; 3) en la dimensión económica: creación de nuevos oficios y actividades económicas, ambulantaje, migración, y elementos que dan mala imagen de la isla; 4) dimensión cultural: la indumentaria tradicional, lengua materna, manifestaciones culturales, cambios en la cultura alimenticia, cosmovisión y saberes indígenas; y 5) dimensión política: los cargos civiles, cargos comunales y cargos religiosos. Así mismo, con las alternativas de solución propuestos por los propios habitantes se diseñaron las bases para la gestión del desarrollo comunitario sustentable en la comunidad indígena de la isla de Janitzio, a partir de la aplicación de la Metodología del Marco Lógico (MML).

This paper introduces a new transient greenhouse model which uses a mechanistic method to estimate the temperature and humidity in typical Chinese solar greenhouses. A novel and easy-to-use wall temperature estimation method based on the energy balance was adopted for the environment model rather than using boundary temperature measurements. In this way, the number of model inputs is considerably reduced, and the proposed model is able to predict future greenhouse climate conditions by utilizing only the weather forecast. The model validation was performed in two different greenhouses (each with different sizes and physical parameters, such as the greenhouse volume, the roof and wall areas, the wall materials and so on) on three typical days in 2019 and 2020, and over four consecutive weeks in different seasons during 2016 and 2019 . Promising results were obtained and the model performed well in different operating modes; these included having the vents completely closed, opening the vents, and completely closing the vents in the cold season with an additional thermal insulation blanket covering. The validation results demonstrate that the proposed model can be widely adapted to different sizes of typical Chinese solar greenhouses, as well as to different weather conditions. Thus, the developed model is a flexible and valuable tool that can be used for greenhouse climate simulation, temperature and humidity control, and as a decision-making support system to help manage solar greenhouses.

In this paper, two models for classification of microalgae species based on artificial neural networks have been developed and validated. The models work in combination with FlowCAM, a device capable of capturing each of the particles detected in a sample and obtaining a set of descriptive features for each one. One of the models uses these feature variables as input, while the other makes use of the captured images, both being able to distinguish between two well-known species of microalgae, Scenedesmus almeriensis and Chlorella vulgaris, calculating the proportion of each of these in the analyzed mixture. The models were trained with pure samples of each specie and validated using mixed combinations of them. The results confirm the potential of image analysis and deep learning techniques for the identification of microalgae cultures, as well as the higher accuracy of the feature-based model, thus extending the range of classification approaches in this field.

The catalyst FeTiO3/ZnO was prepared by ultrasound-assisted chemical precipitation method. The material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM-EDAX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). FeTiO3/ZnO (1, 5, and 10%wt. FeTiO3) was evaluated on photocatalytic degradation of ciprofloxacin (CPX) in an aqueous solution (10 mg L−1) under UV-Vis irradiation. The heterojunction between FeTiO3 and ZnO, the presence of Fe2O3 impurities, and the formation of oxygen vacancies allowed the coupled material FeTiO3/ZnO (1%wt.) showed a better photocatalytic performance (100% degradation CPX and 27% of mineralization) than bare ZnO. Although ZnO also attained complete degradation of CPX, the antibiotic was not mineralized under the same operating conditions. A scavenger study determined that h+ and OH were the principal reactive species involved in the CPX photocatalytic degradation. The heterostructured material showed high stability and reusability during three cycles of use.

In this work, BiOBr photocatalyst co-doped with Fe and N (Fe–BiOBr–N) was synthesized by a microwave-assisted solvothermal method. This material was characterized by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, N2 adsorption-desorption, X-ray photoelectronic spectrometry, UV–Vis diffuse reflectance spectroscopy, atomic absorption spectroscopy, elemental analysis, and photoluminescence techniques. The characterization of this material revealed the formation of flower-like structures and the successful incorporation of Fe and N in BiOBr. The incorporation of Fe and N in BiOBr caused a decrease of the band gap (from 2.87 to 1.92 eV), the crystal size (from 12.93 to 8.43 nm), and the recombination rate of photogenerated charges compared with unmodified BiOBr. Likewise, these dopants caused an increase in specific surface area (from 7 to 16 m2/g). The photocatalytic activity was assessed on the elimination of bisphenol A (BPA) under visible radiation. Fe–BiOBr–N exhibited higher photocatalytic activity than pristine BiOBr on the BPA degradation, allowing complete degradation and 65% of mineralization in 240 min, while using pristine BiOBr 40% of degradation and 20% of mineralization were obtained. Fe–BiOBr–N is a promising option for the effective elimination of persistent contaminants such as BPA in the aqueous medium, under visible radiation.

In this research study, WO3/NaNbO3-coupled photocatalysts were synthesized at three WO3 mass ratios (15, 85, and 95 wt%) and characterized. These composites were characterized via X-ray powder diffraction, N2 physisorption, UV–Vis diffuse reflectance spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, transmission electron microscopy, and photoluminescence techniques. For comparison, bare WO3 and NaNbO3 were also synthesized and characterized. 2,4-Dichlorophenoxyacetic acid (2,4-D) was degraded under visible light to evaluate its photocatalytic performance. The WO3 (95 wt%)/NaNbO3 composite showed higher photocatalytic activity than pure WO3 and NaNbO3 and even than the 15 and 85 wt% coupled materials; thus, the combination with the highest ratio of WO3 with respect to NaNbO3 showed increased photocatalytic activity compared with the bare materials.

The use of semiconductor photocatalysis is a promising, green, and sustainable technology to address solar energy conversion and environmental remediation issues. Among photocatalytically active semiconductors, considerable attention has been given to the visible-light active tungsten oxide (WO3, Eg value ≈ 2.7–3.1 eV). This semiconductor has several advantages: strong absorption in the visible spectrum range, stability in acidic and oxidative conditions, low cost, and low toxicity. However, WO3 presents fast recombination of charge carriers’ and exhibits low photocatalytic activity for reduction reactions due to its conduction band potential (+0.5 V versus NHE). Many strategies have been applied to enhance photocatalytic activity and solar energy utilization of WO3 by modifying the energy band position and reducing the charge carrier recombination. In this review, several approaches, such as designing with exposed facets and specific morphologies, doping with transition metals and non-metals, deposition of noble metals, and heterojunction construction, are summarized. Moreover, the photocatalytic properties of the reviewed WO3-based photocatalysts are discussed based on their environmental applications such as degradation of organic pollutants, air purification, CO2 photoreduction, hydrogen production from water splitting and recently, simultaneous wastewater treatment and electric energy generation by photocatalytic fuel cells. Finally, the summary, future perspectives, and challenges of design novel WO3-based photocatalysts with high efficiency are pointed out to meet the urgent demands of highly efficient technologies that use visible or solar energy for environmental applications.

In this study, the photocatalytic removal of an emerging contaminant, diclofenac (DCF) sodium, was performed using the nitrogen-doped WO3/TiO2-coupled oxide catalyst (WO3/TiO2-N). The catalyst synthesis was accomplished by a sol–gel method using tetrabutyl orthotitanate (C16H36O4Ti), ammonium p-tungstate [(NH4)10H2W12O42·4H2O] and ammonium nitrate (NH4NO3) as the nitrogen source. For comparison, TiO2 and WO3/TiO2 were also prepared under similar conditions. Analysis by X-ray diffraction (XRD), N2 adsorption–desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV–Vis spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS) were conducted to characterize the synthesized materials. The photocatalytic efficiency of the semiconductors was determined in a batch reactor irradiated with simulated solar light. Residual and mineralized DCF were quantified by high-performance liquid chromatography, total organic carbon analysis and ion exchange chromatography. The results indicated that the tungsten atoms were dispersed on the surface of TiO2 as WO3. The partial substitution of oxygen by nitrogen atoms into the lattice of TiO2 was an important factor to improve the photocatalytic efficiency of WO3/TiO2. Therefore, the best photocatalytic activity was obtained with the WO3/TiO2-N0.18 catalyst, reaching 100% DCF transformation at 250 kJ m−2 and complete mineralization at 400 kJ m−2 of solar-accumulated energy.

Photocatalytic degradation of 4-chloro-2-methylphenoxyacetic acid (MCPA) in aqueous solution using Cr(III)-doped TiO2 under UV and visible light was investigated. The semiconductor material was synthesized by a microwave-assisted sol–gel method with Cr(III) doping contents of 0.02, 0.04, and 0.06 wt%. The catalyst was characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), nitrogen physisorption, UV–Vis diffuse reflectance spectroscopy (DRS), and atomic absorption spectroscopy (AAS). The photocatalytic activity for the photodegradation of MCPA was followed by reversed-phase high-performance liquid chromatography (HPLC) and total organic carbon (TOC) analysis. The intermediates formed during degradation were identified using gas chromatography–mass spectrometry (GC–MS). Chloride ion evolution was measured by ion chromatography. Characterization results showed that Cr(III)-doped TiO2 materials possessed a small crystalline size, high surface area, and mesoporous structure. UV–Vis DRS showed enhanced absorption in the visible region as a function of the Cr(III) concentration. The Cr(III)-doped TiO2 catalyst with 0.04 wt% of Cr(III) was more active than bare TiO2 for the degradation of MCPA under both UV and visible light. The intermediates identified during MCPA degradation were 4-chloro-2-methylphenol (CMP), 2-(4-hydroxy-2-methylphenoxy) acetic acid (HMPA), and 2-hydroxybuta-1,3-diene-1,4-diyl-bis (oxy)dimethanol (HBDM); the formation of these intermediates depended on the radiation source.

In this work, an application of the Symmetric Send-On-Delta (SSOD) event-based controllers to the inside air temperature control of the greenhouse production process is presented. The control technique analysis is split into two stages. The first stage is devoted to determine the proper controller parameters and to check the influence of the Send-On-Delta (SOD) threshold value through simulation study. At the second stage, experimental tests on the real greenhouse facilities are performed. The obtained results show that the analyzed control techniques handle the control task with desired accuracy and performance. In particular, the proposed control system saves costs related with energy consumption and wear minimization, by achieving a satisfactory performance at the same time.

This paper addresses the development of a hierarchical control strategy for microalgal production in a tubular photobioreactor. The proposed control scheme is composed of two layers. On one hand, a lower layer is in charge of tracking a pH set-point by a PI controller plus feedforward compensator, which was used due to its recognized efficiency in industrial control processes. On the other hand, the upper layer calculates optimal pH set-points based on an economic model predictive control approach. The main aim of this control scheme is to maximize profits, computed as the difference between the incomes obtained from the final production sale and the associated production costs (including the environmental impact of the exhausted CO2 losses). For this purpose, two types of models have been used depending on the requirements of each layer. Simulated and experimental results of the proposed hierarchical control architecture are presented, as well as a comparison with a single-layer architecture with constant reference implemented by the controller used in the lower layer of the hierarchical structure.

A simple, inexpensive and rapid method was proposed for the determination of bioaccessible arsenic in corn and rice samples using an in vitro bioaccessibility assay. The method was based on the preconcentration of arsenic by cloud point extraction (CPE) using o,o-diethyldithiophosphate (DDTP) complex, which was generated from an in vitro extract using polyethylene glycol tert-octylphenyl ether (Triton X-114) as a surfactant prior to its detection by atomic fluorescence spectrometry with a hydride generation system (HG-AFS). The CPE method was optimized by a multivariate approach (two-level full factorial and Doehlert designs). A photo-oxidation step of the organic species prior to HG-AFS detection was included for the accurate quantification of the total As. The limit of detection was 1.34μgkg(-1) and 1.90μgkg(-1) for rice and corn samples, respectively. The accuracy of the method was confirmed by analyzing certified reference material ERM BC-211 (rice powder). The corn and rice samples that were analyzed showed a high bioaccessible arsenic content (72-88% and 54-96%, respectively), indicating a potential human health risk.

Sierra de Gádor is a karst macrosystem with a highly complex geometry, located in southeastern Spain. In this arid environment, the main economic activities, agriculture and tourism, are supported by water resources from the Sierra de Gádor aquifer system. The aim of this work was to study the levels and behaviour of some of the most significant natural radionuclides in order to improve the knowledge of the hydrogeochemical processes involved in this groundwater system. For this study, 28 groundwater and 7 surface water samples were collected, and the activity concentrations of the natural U-isotopes ((238)U, (235)U and (234)U) and (226)Ra by alpha spectrometry were determined. The activity concentration of (238)U presented a large variation from around 1.1 to 65 mBq L(-1). Elevated groundwater U concentrations were the result of oxidising conditions that likely promoted U dissolution. The PHREEQC modelling code showed that dissolved U mainly existed as uranyl carbonate complexes. The (234)U/(238)U activity ratios were higher than unity for all samples (1.1-3.8). Additionally, these ratios were in greater disequilibrium in groundwater than surface water samples, the likely result of greater water-rock contact time. (226)Ra presented a wide range of activity concentrations, (0.8 up to about 4 × 10(2) mBq L(-1)); greatest concentrations were detected in the thermal area of Alhama. Most of the samples showed (226)Ra/(234)U activity ratios lower than unity (median = 0.3), likely the result of the greater mobility of U than Ra in the aquifer system. The natural U-isotopes concentrations were strongly correlated with dissolution of sulphate evaporites (mainly gypsum). (226)Ra had a more complex behaviour, showing a strong correlation with water salinity, which was particularly evident in locations where thermal anomalies were detected. The most saline samples showed the lowest (234)U/(238)U activity ratios, probably due to fast uniform bulk mineral dissolution, which would minimize the impact of solubility-controlled fractionation processes. Furthermore, the high bulk dissolution rates promoted greater groundwater (226)Ra/(234)U ratios because the Ra has a comparatively much greater mobility than U in saline conditions.

A dynamic model for microalgae production in raceway reactors is developed in this work. The model takes into account fluid-dynamic, mass transfer, and biological phenomena taking place in microalgae bioreactors. The model has been calibrated and validated using real data from a 100 m 2 pilot-scale raceway reactor. Results demonstrate that in raceway reactors large accumulation of oxygen takes place into the channel whereas carbon losses into this section are scarce, these phenomena influencing the overall productivity of the reactor. The model can be used to determine characteristic parameters (biological and engineering ones) of existing reactors. Moreover, it can be used to simulate the effect of different designs and/or operation conditions into the performance of the system. Simulations allow us demonstrating that to increase the productivity of raceway reactors it is recommendable to reduce the water depth into the cultures and to increase the mass transfer capacity of the entire reactor.

This paper describes the development of a distributed sliding mode control controller to regulate the pH of a tubular photobioreactor using the total inorganic carbon as the controlled variable of the process. The main purpose of the control system is to maintain the pH around a desired reference value and, at the same time, attenuate the undesirable transients caused by the disturbances. To study this problem, it is considered that this system is written as a set of hyperbolic partial differential equations. The distributed parameter model of the photobioreactor is transformed into a finite dimensional system by the method of characteristics. Then, the control design is performed in the finite dimensional system instead of the original distributed parameter model. The proposal allows to characterize the sliding regimes and their fundamental properties by a geometric approach. Through simulation and experimental results, the method is shown to be effective in controlling a tubular photobioreactor.

Bio.

Mediante la identificación crítica de 2,250 números de recolecta de plantas vasculares, reunidos de noviembre de 2009 a mayo de 2014, en el predio de Villas de Cacoma, en la sierra de Cacoma, municipio de Villa Purificación, Jalisco se registran 136 familias, 451 géneros, 775 especies y 13 unidades infraespecíficas. Las familias más ricas en géneros y especies son Orchidaceae (41/81), Fabaceae 37/81), Asteraceae (47/77) y Poaceae (22/35). Los géneros con más especies son Quercus (20) , Salvia (11) , Desmodium (10) , Epidendrum (8) y Solanum (8) . Se registra por primera vez para el estado de Jalisco a Myrcia splendens , Solanum lanceifolium y Tourrettia lappacea . Dos nuevas especies se han descrito con base en material recolectado en el área y se amplía la distribución de al menos 10 especies sólo conocidas de la localidad tipo o de áreas muy reducidas. La forma biológica con más especies son las hierbas con el 43.06 % y sólo el 1.15 % son parásitas. El bosque mesófilo de montaña es la vegetación con el mayor porcentaje de especies (45.9 %) seguida por la vegetación ribereña con el 18.8 %. El 36 % de las especies registradas para Villas de Cacoma son endémicas a México y 32 de ellas lo son para el estado de Jalisco.

This study was carried out to determinate phenolic, flavonoid content, and antioxidant capacity in methanolic extract from three Alperujo varieties. Alperujo Barnea showed the highest concentration of phenols and flavonoid. The greater hydroxytyrosol content was obtained in the same extract (4.93 ± 0.37 µg/mg extract), whereas the greater tyrosol content (0.23 ± 0.012 µg/mg extract) was found in Arbequina extract. These results were correlated with the greatest radical scavenging and the highest inhibition of lipoperoxidation process observed in Barnea extract (IC50 of 27.9 ± 1.04 µg/mL; IC50 22.8 ± 3.5 µg/mL, respectively). In spite of differences, alperujo extracts exhibited notable antioxidant capacities.

The improved photocatalyst carbon-doped WO 3 /TiO 2 mixed oxide was synthesized in this study using the sol–gel method. The catalyst was thoroughly characterized by X-ray diffraction (XRD), diffuse reflectance UV–vis spectroscopy, N 2 adsorption desorption analysis, scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic efficiency of the prepared materials was evaluated with respect to the degradation of sodium diclofenac (DCF) in a batch reactor irradiated under simulated solar light. The progress of the degradation process of the drug was evaluated by high-performance liquid chromatography (HPLC), whereas mineralization was monitored by total organic carbon analysis (TOC) and ion chromatography (IC). The results of the photocatalytic evaluation indicated that the modified catalyst with tungsten and carbon (TWC) exhibited higher photocatalytic activity than TiO 2 (T) and WO 3 /TiO 2 (TW) in the degradation and mineralization of diclofenac (TWC>TW>T). Complete degradation of diclofenac occurred at 250 kJ m −2 of accumulated energy, whereas 82.4% mineralization at 400 kJ m −2 was achieved using the photocatalytic system WO 3 /TiO 2 -C. The improvement in the photocatalytic activity was attributed to the synergistic effect between carbon and WO 3 incorporated into the TiO 2 structure.

This paper discusses about a general implementation structure of the filtered Smith predictor for single-input single-output processes with a measurable disturbance. Dead-time free models are used to feed-forward the measurable disturbance into the feedback controller. It is demonstrated that the proposed controller can be applied to control open-loop unstable processes with different time delays associated with control and disturbance signals. Different simulated industrial processes are used to illustrate the proposed strategy properties and advantages over other time-delay compensators.

Display Omitted A greenhouse temperature hybrid model is developed based on linear reduced models.An HMPC is designed to control greenhouse temperature using two heating systems.Simulations results show that the HMPC framework is suitable to solve the greenhouse heating problem. Forced-air heaters and aerial pipe systems are the most common heating equipment used in greenhouses to control the nocturnal temperature in Mediterranean areas. These heating systems are often used separately and they are seldom combined in the same greenhouse for temperature control purposes. The main reasons are that the advantage of combining both heating systems has not been thoroughly analysed in literature, and that, the complexity of the problem increases from a control point of view due to the mixing of different dynamics. The combination of these two heating systems can be useful in some situations, obtaining a reasonable trade-off between thermal gain and running costs. Thus, this paper proposes to analyse the combination of these two heating systems and provide a solution to the problem of switching two different heating systems to control the nocturnal temperature in a greenhouse by using a hybrid controller. The proposed controller counteracts the switching disadvantages presented by commercial systems based on heuristic rules. To achieve this solution, the system dynamics are represented through a hybrid model, where weather variables act as logical conditions to switch between the different process dynamics. This approach allows considering the greenhouse dynamics as a hybrid system with continuous and discrete components. A Model Predictive Hybrid Controller is used to regulate the inner temperature during the night and calculates optimal control signals based on power consumption and commutation minimisation. The performance of this controller is studied, comparing its reference deviation, number of commutations, and running costs against commercial controllers. The final results show that the adequate combination of these heating systems can contribute to a much better control performance with a minor cost increment.

Phyllodes tumour is a fibroepithelial neoplasm of the breast, with a low world incidence, and with few prospective trials on its diagnosis and treatment. A review is presented of the available world medical literature on this topic. Phyllodes tumours can currently be classified as benign, borderline and malign. This classification helps to determine the surgical treatment, which is the cornerstone of the treatment of Phyllodes tumour, as well as the adjuvant treatment, and finally it helps to determine the patient's prognosis.

Five endocrine-disrupting compounds (EDCs) were determined in four urban wastewater treatment plants (WWTPs) of the Metropolitan Area of Monterrey (MAM) in two seasonal periods (winter and summer). The MAM, one of the most urbanized areas in Mexico, is characterized by high industrial activity and population density, leading to extensive use of several EDCs. In the MAM, ∼90% of urban and industrial wastewater is treated in WWTPs, where EDCs can be partially eliminated. In this work, dissolved levels of 17β-estradiol (E2), 17α-ethinyl estradiol (EE2), bisphenol A (BPA), 4-nonylphenol (4NP), and 4-tert-octylphenol (4TOP) in wastewater were determined. The EDCs' determination was carried out through solid-phase extraction (SPE) and gas chromatography coupled to mass spectrometry (GC-MS). High EDCs levels (0.4-450 ng/L) were found in the influents of WWTPs, while concentrations in the effluents ranged from 0.2 to 26.8 ng/L, with E2, EE2, and 4TOP being the most persistent. The Spearman correlation analysis revealed the association between E2 and EE2 (r = 0.4835, p 0.05), and between BPA and 4NP (r = 0.5180, p 0.05), suggesting that these EDCs have similar sources. Also, E2, BPA, and 4TOP were positively correlated with the chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total suspended solids (TSS) (r = 0.4080-0.5694, p 0.05), indicating the association of the EDCs with the organic matter in the wastewater. The factor analysis confirmed the significant correlation of COD, BOD, TSS, temperature, and pH with the high occurrence of 4TOP during the summer. It was also confirmed that summer warmer temperatures favored the removal of BPA and 4NP in the studied WWTPs. Finally, the studied sites were classified by cluster analysis in three groups, revealing the impact that seasonality has on the behavior of the selected EDCs.

Phosphogypsum (PG) is disposed worldwide in large stacks usually placed in coastal zones, as in the case of Huelva (SW of Spain), where around 100 Mt of PG are stored on the salt marshes of the Tinto River estuary covering a surface of about 1000 ha. This management generates the weathering of PG, and due to its high acidity (pH ≈ 2) and pollutant load can provoke significant emissions into their surroundings. In this work were evaluated by laboratory experiments the effects of pH increase in the behaviour of heavy metals and natural radionuclides during the mixing of phosphogypsum leachates with seawater. The acidic phosphogypsum leachates showed concentrations of heavy metals from two to three orders of magnitude higher than natural continental waters, and natural radionuclides (U-isotopes and 210Po) from four to five orders of magnitude higher than unperturbed aquatic systems. Major elements and some heavy metals as Mn, Ni, Cd, As, Sb and Co showed a conservative behaviour during the neutralisation of the leachates with seawater, remaining in the liquid phase, while other ones as Al, Fe, Cr, Zn, Cu, Pb precipitated and/or were adsorbed onto the solid phase. The U-isotopes and 210Po showed a clear non-conservative behaviour probably due to coprecipitation/adsorption processes onto the formed precipitates, but while 210Po reached a total removal at pH ≈ 7, U- isotopes after a total removal at pH ≈ 5 returned into the liquid phase due to redissolution/desorption processes at near neutral pH. The formed precipitates, mainly composed by iron phosphates particles, showed heavy metal and natural radionuclide concentrations from one to three orders of magnitude higher than unperturbed soils. All these facts demonstrate the serious environmental impact produced by the PG stacks into their surroundings and the urgency of effective restoration measures., This work was partially supported by Spanish Ministry of Economy and Competitiveness [project number, CTM2015-68628-R], the Spanish Ministry of Science, Innovation and Universities [project number, EQC2018-004306-P], the Regional Government of Andalusia [project number, FEDER2018-UHU-1255876] and the Spanish Ministry of Education [grant number FPU15/00646].

[EN] This manuscript presents a general overview of the microalgae production process from a modelling and control perspective. First, the main advantages and the potential of these microorganisms are motivated, describing the dierent type of reactors used for their cultivation. Afterwards, the process dynamics, which is very complex and variable due to diary and annual changes on ambient conditions, is analyzed and the main balance equations to describe the system behaviour are introduced. Then, dierent biological and structural models validated in industrial plants will be presented. Subsequently, the existing control problems in these systems are described, introducing a wide set of control algorithms that have been experimentally evaluated in industrial reactors. Finally, the most relevant aspects discussed along the paper are summarized., [ES] Este artículo presenta una visión general sobre el proceso de producción de microalgas desde un punto de vista de modelado y control de procesos. En primer lugar se exponen las ventajas y el potencial de este tipo de microorganismos, así como los distintos tipos de reactores que se suelen utilizar para su producción. Posteriormente, se analiza el comportamiento dinámico de este tipo de procesos, el cual es muy complejo y cambiante debido a variaciones en las condiciones ambientales tanto diarias como anuales, y se presentan los distintos balances que permiten describir la evolución de las principales variables del sistema. Se exponen distintos tipos de modelos a nivel biológico y a nivel estructural que han sido validados a escala industrial. Tras analizar su comportamiento dinámico, se motivan los distintos problemas de control existentes en este tipo de sistemas y se resume una amplia batería de estrategias de control que han sido evaluadas con éxito en fotobiorreactores industriales. Finalmente, se concluye el trabajo con un balance de los aspectos más importantes expuestos a lo largo del mismo., Este trabajo ha sido realizado parcialmente gracias al apoyo del Ministerio de Economía y Competitividad con el proyecto DPI2017-84259-C2-1- R y el Programa de Investigación e Innovación Horizonte 2020 de la Unión Europea en el marco del proyecto SABANA (No. 727874).

The mercury pollution of the soil and water environments in a mining area of Villa Hidalgo, San Luis Potosi, Mexico, and its effects on the area's soil characteristics were evaluated. Soil and water were collected from seven localities in Villa Hidalgo in the autumn of 2016. The physicochemical and mineralogical characteristics of the soil samples were analyzed. Water samples were obtained from wells used for human activities, such as irrigation, housework, and human consumption. The total mercury (THg) content in the water at the monitoring sites was lower than the threshold value and related to some physicochemical water quality parameters. Regarding soil characteristics, the samples were mainly composed by O, Si, Ca, Al, and Fe, and the associated minerals included grossularite, labradorite, and orthoclase. The distribution of the Hg fractions and Hg species in the soil samples were investigated; the THg content ranged from 0.34 to 41.76 mg kg−1, which exceeded the national regulations for a single site. The residual mercury was the main Hg fraction in the soils, and methylmercury was not detected. The relationships between the mercury fractions and the physicochemical and mineralogical characteristics of the soils demonstrated that low organic carbon content and high concentrations of iron, aluminum, and calcium are the most important factors that affect the soil fraction distribution and low mercury mobility in the area. These results could indicate the association of mercury with sulfides, silicates, and crystalline oxides of iron and manganese. A relatively low degree of potential risk for the population (children and adults) was corroborated with the results of the hazard indexes (HI: 3.0 × 10−2 – 2.1 × 10−1); however, these values can be underestimated, since there could be other Hg exposure sources.

The increased use of concentrates to reduce pasture as a feed source in productive systems like Payoya breed goat farms has made it necessary to decrease feeding costs. The inclusion of agro-industry by-products such as dry orange pulp pellets in goat diets has been suggested as a sustainable alternative to cereal-based concentrates. The aim of this work was to assess the influence of diets including dry orange pulp pellets on the quality of cheeses traditionally made from Payoya breed goat milk. We analysed the physicochemical characteristics, sensory properties and volatile compound profiles of 18 artisanal cheeses made from raw Payoya milk. In this study, goats were fed with different concentrations of dry orange pulp, and cheeses were curdled with animal and vegetable coagulants. Slight differences were detected between some cheeses. However, the use of citrus by-products in the Payoya goat diets did not substantially affect the cheeses&rsquo, physicochemical properties, olfactory attributes, or volatile profiles. Therefore, dried citrus pulp can be used as a substitute for cereal concentrates without affecting the distinct properties of these ripened raw goat milk cheeses.

A multifaceted hydrogel-based formulation was reported. The hydrogel was prepared by crosslinking cellulose and substituted chalcone. Moreover, the formulation was conjugated with carbon nanotubes with the aim of increasing the loading amount of bioactive compounds such as allantoin, dexpanthenol, resveratrol and linezolid. The hydrogel formation was confirmed by swelling tests, FT-IR spectroscopy, thermogravimetric analysis and SEM. The hydrogel showed an improved release rate of therapeutic substances, exhibiting a simultaneous and coordinated release according to the chromatographic studies. The efficacy of drug release was confirmed by wound closure and in vivo wound healing studies that showed promising healing results. The antibacterial assays demonstrated that the sustained release of linezolid tends to be very effective. In conclusion, a multifaceted formulation based on carbon nanotube-containing cellulose-chalcone was developed that can potentially be utilized in treating complex wounds owing to its improved wound healing properties and prevention of potential infections.

This research was focused on the analyses of the hydrochemical behaviour of long-lived natural radionuclides (210Po, 210Pb, 234,238U, 230,232Th, 226,228Ra) in groundwaters from Spanish aquifers with different geological characteristics and the evaluation of the dose by ingestion of these waters. The study was performed by the gross alpha-beta, alpha spectrometry and physicochemical analysis of a set of bottled drinking waters. Radionuclide activities in the investigated aquifers were highly variable. High concentration of 210Pb is associated with granitic bedrock and reducing conditions. On the other hand, the highest 238,234U concentrations were found in carbonate aquifers. Activities of 226Ra are largely controlled by ion exchange reactions due to the presence of relatively high concentration of chloride. Several waters exceeded the parametric value for gross alpha mainly due to 234U, 226Ra and/or 210Pb concentrations. Moreover, the content of 226Ra and 210Pb in the water contributed mainly to the indicative dose.

Phosphorous-doped Ti-Fe mixed oxide (P-TiO2-αFe2O3) catalysts were prepared by the microwave-assisted sol-gel route and characterized using XRD, SEM, N2 physisorption, UV–vis diffuse reflectance, FTIR, and XPS. P-TiO2-αFe2O3 was evaluated during the degradation of a sulfonamide mixture (5 mg/L, each) under visible light. The photocatalytic process was optimized with a face-centered central composite design. Under optimal conditions (0.5 wt% of αFe2O3, pH 10, and 0.75 g/L of catalyst loading), the sulfate radical advanced oxidation process was carried out using 5 mM K2S2O8 (PS). P doping shifted the light absorption of P-TiO2-αFe2O3 in the visible light range owing to substitutional doping, while the coupling of P-TiO2 with α-Fe2O3 enhanced the absorption in the visible range, which resulted in an increase in the lifetime of the charge carriers and in a superior photoactivity of the P-TiO2-αFe2O3 catalyst in comparison to that of TiO2. The mineralization yield of the sulfonamides (SNs) mixture was enhanced in the presence of an electron acceptor (SO4− ), allowing nearly 69 % within 300 min with the P-TiO2-αFe2O3/PS system, while P-TiO2-αFe2O3 and K2S2O8 oxidation achieved only 27 % and 21 %, respectively. The biodegradability index was 0.48 using the P-TiO2-αFe2O3/PS system, indicating a less toxic effluent than the original compounds. Recycling tests demonstrated that P-TiO2-αFe2O3 exhibits good stability in activating PS for SNs degradation during three cycles. Two main intermediates (pyrimidine and hydroquinone) and their hydroxylated re-arrangements were detected during the degradation of the SNs by the coupled process. Oxalic, oxamic, sulfonic, and acetic acids were also identified as by-products from the degradation of the SNs.

There is a growing interest in the study of oils from native fruits, especially when the oil has high quality. In this sense it is mandatory to evaluate the oxidative stability and the relationship with the modifications of the fatty acid content, physicochemical parameters, the antioxidant capacity and its protection against the thermal deterioration processes. The fatty acid profiles of Chilean hazelnut oil showed a relevant presence of the omega series (ω-9, ω-5, and ω-9) with good stability across the thermal treatment. The physico–chemical parameters such as polar compounds and absorption coefficients K232 and K270 showed a similar behavior compared with olive oil oxidation in the range of 25–360 °C. The antioxidant capacity and total phenolic content in olive oil is significatively higher than Chilean hazelnut oil at 25 °C; however, this antioxidant capacity decreases in the olive oil after 100 °C; until 247 °C the antioxidant capacities for both oils are equalized. Total phenolic content of olive oil diminishes after 100 °C until the final study temperature (360 °C), where its concentration is very similar to Chilean hazelnut oil. The results of the thermogravimetric and differential analysis in the range of 100–700 °C show that the thermal oxidative decomposition processes occurred in both samples mainly in three steps with a total mass loss for olive oil and Chilean hazelnut oil of 99.7% and 99.9%, respectively. It is important to note that hazelnut oil remains thermally stable up to 247 °C just a few degrees lower than olive oil (252 °C)., Oscar Forero-Doria Thanks FONDECYT (FONDECYT Postdoctoral Fellowship No. 3170757) and Luis Guzmán thanks FONDECYT (FONDECYT Initiation No. 11150390).

The improvement of photosynthetic efficiency in a 100 m2 raceway reactor by enhancement of light regime to which the cells are exposed is here reported. From Computational Fluid Dynamics it was calculated that the light exposure times ranged from 0.4 to 3.6 s while the exposure times to darkness were much longer, from 6 to 21 s. It was demonstrated that these times are too long for light integration, the cells fully adapting to local irradiances. This phenomenon was validated in the real outdoor raceway at different seasons. Simulations allows to confirm that if total light integration is achieved biomass productivity can increase up to 40 g/m2·day compared to 29 g/m2·day obtained considering local adaptation, which is close to the experimental value of 25 g/m2·day. This paper provides clear evidence of microalgae cell adaptation to local irradiance because of the unfavourable cell movement pattern in raceway reactors.

In this paper, a control scheme based on feedback linearization technique and quantitative feedback theory (QFT) is used to regulate the inner diurnal temperature in a greenhouse located in the south of Spain. In a first step, a non-linear model for the greenhouse is used to design a feedback linearization controller, which provides the vents opening percentage from a virtual control signal provided by a robust proportional integral (PI) controller. The relation between the system output (inside temperature of the greenhouse) and the virtual control signal is given by a first order plus dead time (FOPDT) system. The values for the three parameters of this linear model are identified in the experimental greenhouse by applying several step changes in the virtual control signal and analyzing the process response. Different values for gain, the time constant, and time delay are identified. So, this uncertain linear description for the system is used to design a quantitative feedback theory (QFT) controller with a PI structure. Finally, experimental results are analyzed showing satisfactory performance of the proposed control approach.

Radon measurements were performed in Huelva, a city located near a phosphogypsum repository in the SW of the Iberian Peninsula, between March 2015 and March 2016. The mean values of this gas oscillate between 5.6 and 10.9 Bq m−3 and maximum ranges between 36.4 and 53.4 Bq m−3. Radon shows the expected monthly variation with higher levels in November and December. Typical daily evolutions were also observed, with maximum between 06:00 and 08:00 UTC (Coordinated Universal Time) and minimum around noon. To extract daily radon patterns, the cluster technique of K-means was applied. Based on this classification, four different case study periods were analyzed in detail, describing two events with high radon levels and two with low radon. Local meteorology, back-trajectories computed with the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model and meteorological fields from the WRF (Weather Research and Forecasting) model, were used to analyze the four case study periods selected. Low radon periods are characterized by the occurrence of non-pure breezes and maritime air masses from the Atlantic Ocean, whereas high radon periods occur under pure sea-land breezes affected by Mediterranean air masses. Factors such as meteorology or local emission sources alone may not be enough to explain the high radon events in the area. Other factors could be playing a major role in the radon levels. The obtained results indicate the contribution of radon transported from medium-long range, suggesting that, under specific weather conditions, the Gulf of Cadiz could act as a radon trap and the continental areas around the Western Mediterranean Basin could act as a radon source.

[Resumen] Este trabajo presenta un sistema de control adaptativo para un recuperador de gases como parte de una planta termosolar híbrida. La variable que se desea controlar en este sistema es la temperatura de salida de las sales, que presenta una dinámica fuertemente no lineal afectada por los flujos másicos de sales y gases. Por ello, el propósito de este artículo ha sido obtener los modelos necesarios para elaborar una estrategia de control con un buen desempeño en todos los puntos de operación, sin necesidad de hacer uso de modelos no lineales, y utilizando esquemas de ajuste de ganancia por tabla e interpolación de parámetros. El algoritmo de control ha sido evaluado por completo en simulación obteniendo resultados satisfactorios. [Abstract] This paper presents a non-linear control approach for a heat recovery system in a hybrid power plant. The salt temperature is the controlled variable, which presents a highly non-linear dynamics, affected by the salt and gas mass ows. Therefore, the aim of this paper is to obtain the process models to elaborate a control strategy with an adequate performance in the desired operating point, without making use of non-linear models, and employing gain scheduling and parameter interpolation control schemes. The control algorithms have been completely evaluated in simulation obtaining satisfactory results. Ministerio de Economía y Competitividad; DPI2017-85007-R

The photocatalytic degradation of a sodium diclofenac (DCF) solution (10 mg/L) under simulated solar radiation was evaluated using a ZnO semiconductor modified by the incorporation of 10, 15, and 20 wt.% fluorine (ZnO-F10, ZnO-F15 and ZnO-F20). The ZnO-F catalysts were synthesized by the sol-gel method using zinc acetate as a precursor of zinc oxide and NH4F as a fluorine source. The photocatalytic performance of the F-doped ZnO material was compared to that of bare ZnO. The obtained photocatalysts were characterized using X-ray diffraction (XRD), Scanning electron microscopy with Energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) techniques. The Brunauer-Emmett-Teller (BET) surface area, pH of zero charge (pHpzc), and band gap of the solids were also evaluated. An experimental Box-Behnken design combined with response surface methodology was applied to establish the optimal conditions for the photocatalytic degradation of the DCF solution. Complete DCF degradation, total release of chloride ions, and approximately 90% mineralization were achieved during degradation of the drug at an accumulated energy of 400 kJ/m2 under the optimized experimental conditions (1 g/L of ZnO-F20 catalyst with the pH of the DCF solution maintained at 6.5).

Ocupada Lima por el Ejercito chileno y puesto en fuga el dictador Nicolas de Pierola, emerge un Gobierno de «notables» en la capital, bajo la presidencia de Francisco Garcia Calderon. Cuenta este con la anuencia de Chile, por- que se cree que aceptara la paz con la cesion de Tarapaca. Pero el nuevo mandatario, que representa al grupo peruano interesado en el salitre, realmente busca preservar esa riqueza. Se esperanza en la intervencion norteamericana y negocia con el Credit Industriel de Francia un emprestito que condujera a la obtencion de la paz a cambio de una crecida indemnizacion. A la vez, paga un considerable cupo al invasor valiendose de un prestamo e incrementa asi la deuda interna peruana. El examen de algunos de sus discursos lo revela como lider de la clase dominante. Considera «ciudadanos» a los miembros de su grupo y toma distancia del «pueblo trabajador», aunque le exige apoyo a cambio de retornar al «orden». Esto supone terminar con la resistencia que ha surgido allende la cordillera, pero fracasa en ello estrepitosamente. A la postre, el alto mando chileno entiende que Garcia Calderon no sirve a sus intereses, al tiempo que descubre la trama secreta sobre el salitre de Tarapaca y pone entonces fin a la farsa de La Magdalena. Parte de la informacion sobre estos hechos procede de la prensa coetanea, peruana y extranjera.

A fully automated on-line system for monitoring the TiO2-based photocatalytic degradation of dimethyl phthalate (DMP) and diethyl phthalate (DEP) using sequential injection analysis (SIA) coupled to liquid chromatography (LC) with UV detection was proposed. The effects of the type of catalyst (sol-gel, Degussa P25 and Hombikat), the amount of catalyst (0.5, 1.0 and 1.5 g L-1), and the solution pH (4, 7 and 10) were evaluated through a three-level fractional factorial design (FFD) to verify the influence of the factors on the response variable (degradation efficiency, %). As a result of FFD evaluation, the main factor that influences the process is the type of catalyst. Degradation percentages close to 100% under UV-vis radiation were reached using the two commercial TiO2 materials, which present mixed phases (anatase/rutile), Degussa P25 (82%/18%) and Hombikat (76%/24%). 60% degradation was obtained using the laboratory-made pure anatase crystalline TiO2 phase. The pH and amount of catalyst showed minimum significant effect on the degradation efficiencies of DMP and DEP. Greater degradation efficiency was achieved using Degussa P25 at pH 10 with 1.5 g L-1 catalyst dosage. Under these conditions, complete degradation and 92% mineralization were achieved after 300 min of reaction. Additionally, a drastic decrease in the concentration of BOD5 and COD was observed, which results in significant enhancement of their biodegradability obtaining a BOD5/COD index of 0.66 after the photocatalytic treatment. The main intermediate products found were dimethyl 4-hydroxyphthalate, 4-hydroxy-diethyl phthalate, phthalic acid and phthalic anhydride indicating that the photocatalytic degradation pathway involved the hydrolysis reaction of the aliphatic chain and hydroxylation of the aromatic ring, obtaining products with lower toxicity than the initial molecules.

An automated method for the analysis of methylparaben, propylparaben, benzophenone-3, and benzophenone-4 in water effluents via on-line solid-phase extraction coupled with high-performance liquid chromatography/ultraviolet detection was proposed. The preconcentration parameters were studied using Plackett-Burman and Box-Behnken experimental designs using a C18 sorbent material. The results demonstrated that the eluent volume, composition, and sorbent amount were statistically significant. Optimal conditions for these variables were an eluent volume of 1.55 mL, eluent composition of acetonitrile 100% v/v, and sorbent amount of 100 mg. The eluted sample was analyzed on-line using high-performance liquid chromatography equipped with a reversed-phase C18 column and ultraviolet detection. Separation of the analytes was achieved in 15 min using gradient elution with acetonitrile/water. A simple, sensitive, and rapid analytical method was proposed for personal care compounds without sophisticated or expensive equipment. The limits of detection were 1.20, 1.73, 2.51, and 4.67 μg/L for propylparaben, methylparaben, benzophenone-3, and benzophenone-4, respectively. The analysis time was 48 min, consuming only 1.59 mL of eluent acetonitrile for the solid phase extraction step, with minimal sample handling. The method was applied to the analysis of spiked swimming pool and wastewater, with recoveries between 65-107%. These results indicate the reliability of the flow-based procedure.

Currently, cancer is the second most common cause of death in the United States, exceeded only by heart disease. Chemotherapy traditionally suffers from a non-specific distribution, with only a small fraction of the drug reaching the tumor, in this sense, the use of dendrimers incorporating drugs non-covalently encapsulated inside the dendrimer or covalently conjugated have proven to be effectives against different cancer cell lines. However, at present the dendrimers used as drug-carriers still do not meet the necessary characteristic to be considered as an ideal dendrimer for drug delivery; high toxicity, bio-degradability, low toxicity, biodistribution characteristics, and favorable retention with appropriate specificity and bioavailability have not been fully covered by the current available dendrimers. However, the development and study of new dendrimers drug-carriers continues to be an important tool in the cancer therapy as they can be functionalized with varied ligands to reach the tumor tissue through the different body barriers in the body with minimal loss of activity in the bloodstream, have the ability to selectively kill tumor cells without affecting the normal cells and most important with a release mechanism controlling actively. Given the continuous efforts and research in this area of interest, we presented in this review the work done with a special emphasis on the development of dendrimers as a major tool in the combination with drugs, as a potential adjunctive agent in anticancer therapy.

espanolResumen: Con el objetivo de cuantificar los cambios espacio-temporales de atributos estructurales y de composicion floristica de especies arboreas del bosque mesofilo de montana en el occidente de Mexico, se establecieron ocho parcelas permanentes de 2 500 m2 cada una. En ellas se registraron variables estructurales (densidad, frecuencia, area basal y valor de importancia relativo-VIR) y de composicion floristica (riqueza de especies, generos y familias) en tres tiempos diferentes: primer censo en 1998 (C1); segundo censo en 2004 (C2) y tercer censo en 2010 (C3). Los resultados indican que existen diferencias significativas, tanto para las variables estructurales como en la composicion de especies, generos y familias en el espacio (entre parcelas) y el tiempo (entre censos). La densidad incremento de 1190 a 1239 individuos ha-1 entre el C1 y C2 y disminuyo a 1164 en el C3. El area basal promedio por ha fue de 36.15, 36.19 y 37.53 m2 para los C1, C2 y C3, respectivamente. Styrax radians, Siparuna thecaphora y Conostegia xalapensis tuvieron una frecuencia del 100%. Styrax radians registro los valores mas altos de VIR en los tres censos junto con Ficus aurea y Quercus iltisii. Los cambios espacio-temporales en estructura y composicion floristica estuvieron asociados con caracteristicas biologicas propias de cada especie (germinacion y dispersion) y con perturbaciones antropicas como ganaderia, agricultura de subsistencia, caida de arboles, corta clandestina de madera y cambio de uso del suelo. EnglishAbstract: Changes in structure and taxonomic composition of the arboreal component of a tropical montane cloud forest were monitored along 12 years (1998, 2004 and 2010) with eight 2,500 m2 permanent plots in south-central Jalisco, Western Mexico. Changes in structure (density, frequency, basal area and relative importance value index-IVI) and composition (species, genera and family richness) were recorded. Results revealed significant differences in structure and composition among plots and within plots monitored at different times. Density increased from 1 190 to 1 239 individuals ha-1 between 1998 and 2004 and then reduced to 1 164 individuals from 2004 to 2010. Average basal area per hectare was similar in 1998 (36.15) and 2001 (36.19) and increased slightly in 2010 (37.53 m2). Styrax radians, Siparuna thecaphora and Conostegia xalapensis displayed the highest relative frequency 100% relative frequency. Styrax radians followed by Ficus aurea and Quercus iltisii.had the highest IVI in 1998, 2004 and 2010. Spatio-temporal changes in structure and floristic composition were associated with germination and dispersal and with human disturbance caused by livestock, subsistence farming, falling trees, illegal cutting and land use change.

On-line sample pretreatment (clean-up and analyte preconcentration) was coupled to sequential injection chromatography for the determination of 2, 4-D (2,4-dichlorophenoxyacetic acid) and atrazine in corn samples. Prior to their analysis, microwave-assisted approach was evaluated and optimized for the extraction of 2,4-D and atrazine in corn samples. Extraction was carried out using MeOH:water (30:70 v/v) solvent at 50°C for 15 min. The on-line SPE-HPLC/UV approach combined reversed solid-phase extraction using strata X sorbent with MeOH:H2O (80:20 v/v) at 1 mL min-1 as eluent for the enrichment of the analytes. C18 monolithic column with acetonitrile:10 mM acetate buffer pH 4 (20:80, v/v) was employed as mobile phase at 2 mL min-1 flow rate for separation of the compounds before UV detection. Enrichment factors up to 13.4 were achieved with a 10 mL sample volume. The developed procedure showed linear response ranges from 0.07–0.70 mg kg−1 for 2,4-D and atrazine with correlation coefficients >0.993. The LODs were 0.03 and 0.02 mg kg-1 for 2,4-D and atrazine, respectively with RSD ranged from 4.0 to 7.2 % at 0.07 and 0.30 mg kg-1. The recoveries of 2,4-D and atrazine in corn samples were from 82.6 and 98.2%. The proposed method showed good recoveries and reasonable precision for herbicide analysis in corn samples avoiding the time-consuming batch sample pretreatment step, thus minimizing risks of sample contamination and analyte losses.

A large amount of the daily activities carried out by people takes place in buildings, which implies the need to maintain optimal thermal comfort conditions, while trying to keep energy consumption at acceptable levels. This work presents the design of a nonlinear controller aimed at improving the operation of a fan-coil unit (FCU) based on feedback linearization techniques. Data for modeling and control purposes were obtained from a room of the CIESOL bioclimatic building located at the University of Almeria, South East Spain. Results demonstrate how advanced control techniques help to improve the operation of heating, ventilating and air conditioning (HVAC) systems in buildings.

Modern engineering projects are multidisciplinary and involve the integration of diverse elements. Within this context, automatic control plays a crucial role. Automatic control is an area of knowledge with significant mathematical content, including differential equations, linear algebra, differential geometry, and/or complex variable among others [1]. Consequently, in many cases, automatic control is difficult for most students to grasp, especially in those cases where students have only an introductory control course in their engineering curriculum. Thus, teachers look for ways to introduce and make automatic control attractive for the students [2]. From the very beginning, graphical representation has been used as support in automatic control teaching. Looking back to the pioneering books in automatic control [3]-[11], it can be seen that there are plenty of schematics and figures. Graphical abstraction was also used to contribute to theoretical understanding [12]. Most of the relevant automatic control concepts, such as systems interconnection, frequency response, stability analysis, time response, and/or root locus, have been displayed graphically [13]. This type of representation has been considered for years as an excellent way to introduce automatic control concepts.

This paper is concerned with microalgal biomass production optimization in outdoor tubular photobioreactors. The main purpose of such optimization system is to calculate the culture medium flow rate in order to maximize the biomass production over a determined period of time. Two different methods are shown in this work: (i) an optimal and (ii) a near-optimal strategy. The optimal strategy belongs to the optimal control theory. In this context, a direct method is used to discretize the control problem and a nonlinear programming technique is applied into the resulting optimization problem. The near-optimal strategy calculates only the culture medium injection time, while the culture medium flow rate is maintained constant during this time. For this aim, a photobioreactor model, under real environmental and culture conditions, is used to compute the injection time. This strategy is mostly important for those photobioreactors that are not equipped with a continuous culture medium valve. Simulation and experimental results allow the user to evaluate the effectiveness of the biomass production optimization strategies proposed in this work, compared with a classical harvesting strategy.