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El pasado, lejos de ser un tiempo remoto enmarcado en la reminiscencia y en degradé, está latente y es susceptible al cambio. El presente escrito tuvo como principal objetivo, a través de algunas metodologías que brindan campos del conocimiento como la etnografía, la sociología y la historia del arte, captar y profundizar en la presencia de la iconografía precolombina en el arte urbano y el grafiti en la ciudad de Bogotá, en espacios convencionales y no convencionales; se trató de un acercamiento epistemológico a la práctica de la pintura mural con alusiones a elementos precolombinos. De esta forma, a través de las derivas urbanas por lugares de circulación diaria y en algunos casos aleatorias, el análisis visual iconográfico e iconológico, el mapeo y la entrevista cualitativa, se reflexionó sobre más de veinte pinturas murales, a partir de las cuales se propusieron planteamientos teóricos en relación con el uso del espacio público, por un lado, y el uso de los símbolos, por el otro. Se concluyó que estas intervenciones artísticas, al participar en la construcción y reconstrucción del tejido social, permiten comprender el espacio como un fenómeno volátil; asimismo, que en el ejercicio de reflexionar sobre la presencia del arte en la ciudad es imperativo atender a las condiciones de producción de una pieza, en la medida en que históricamente las imágenes han sido potentes herramientas semánticas que cargan con un objetivo. Finalmente, lo que aquí se plantea es aprender a observar. Las presentes reflexiones se inscribieron en un proceso de investigación propuesto para la clase “Usos del pasado en el presente: la iconografía de la Antigüedad en la cultura contemporánea”, de la Universidad de los Andes, en el primer semestre del 2023.

Abstract The integrated management paradigm proposes dealing with a resource, such as water, considering its interrelationships with other environmental components. This vision has been adopted as a policy in several countries, including Colombia, but its results have not been satisfactory. This article studies the “integrative” approach in previous regulatory arrangements, making a historical review of them to understand how the perception and management of the environment by societies in Colombia have evolved. We show how the notion of a complex and integrated environment is not exclusive from current policies but has been present in the laws for several centuries, so its consideration does not guarantee success. Strategies are proposed to improve the results of recent regulatory arrangements.

Likert-scale surveys are the undeniable protagonists of online evaluations. They ask the respondent to express their degree of agreement with a series of statements related to the development of a subject. In contrast, in social networks, dichotomous surveys are mostly used. They force respondents to polarize their opinions by selecting “like” or “dislike”. This study compares the efficacy of binary and Likert surveys in gathering student opinions on mechanical engineering program subjects. Using Bayesian analysis, it analyzes the similarity of responses obtained from both formats. For each question and scale, the ratio of “I like” among the total responses collected was calculated. The Bayesian factor method was used to compare the ratios obtained. The null hypothesis was equality between the ratios obtained by the different scales for the same question. This hypothesis was rejected in only 7 of the 49 questions evaluated—less than 15%. Finally, the students were surveyed on the preference for use of both scales. More than 80% stated a preference for the use of the dichotomous format. In view of the results obtained, we recommend more frequent use of the dichotomous scale to gather students’ opinions.

Thermal simulations have become increasingly popular in assessing energy efficiency and predicting thermal behaviors in various structures. Calibration of these simulations is essential for accurate predictions. A crucial aspect of this calibration involves investigating the influence of meteorological variables. This study aims to explore the impact of meteorological variables on thermal simulations, particularly focusing on ships. Using TRNSYS (TRaNsient System Simulation) software (v17), renowned for its capability to model complex energy systems within buildings, the significance of incorporating meteorological data into thermal simulations was analyzed. The investigation centered on a patrol vessel stationed in a port in Galicia, northwest Spain. To ensure accuracy, we not only utilized the vessel’s dimensions but also conducted in situ temperature measurements onboard. Furthermore, a dedicated weather station was installed to capture real-time meteorological data. Data from multiple sources, including Meteonorm and MeteoGalicia, were collected for comparative analysis. By juxtaposing simulations based on meteorological variables against those relying solely on in situ measurements, we sought to discern the relative merits of each approach in enhancing the fidelity of thermal simulations.

Abstract Background Early onset of a gilt´s puberty is needed for adequate economic performance in farms, because it indicates her reproductive performance and longevity. Therefore, an effective diagnosis is needed. Our purpose was to compare different procedures (external characteristics, blood progesterone analysis and ultrasonography diagnosis) to detect puberty in 70 gilts (Topigs TN70; 240 days old) on farm conditions. Postmortem examination was the standard reference. Multiple logistic regression analysis was used to identify which combination of independent variables (predictors) best predicts the status of gilts. Results Puberty (46/70 gilts; 65.71%) was characterized by the presence of follicles larger than 6 mm, corpus albicans, corpus rubrum, and corpus luteum (postmortem examination). Vaginal length, body condition, backfat, carcass weight and progesterone blood concentration were significantly higher in pubertal than prepubertal gilts (P

Este artículo tiene como objetivo analizar los nuevos derroteros de la literatura infantil que, en contraposición a los títulos, obras y lecturas de carácter didáctico, ejemplarizante y aleccionador que redundan tanto en la escuela como en los espacios académicos, se asientan sobre la diversidad, la pluralidad y la diferencia. Dentro de las emergencias temáticas y estéticas del siglo XXI, aquí se analizan las propuestas narrativas y estéticas con temática queer a través del libro-álbum. Esta tipología literaria, en la que palabra e imagen funcionan simbióticamente, sirve como mediador para no solo romper con el tabú y la censura presupuestos en el mundo del adulto, sino para incorporar una mirada reflexiva en torno a la diversidad sexual en la construcción subjetiva e identitaria. Dado su enfoque cualitativo, se adelanta un análisis documental de los libros-álbum y la crítica literaria, y se implementarán la triangulación de datos y teórica a partir de los postulados de Judith Butler, Eve Sedgwick y Paul Preciado, en torno a la performatividad, la crisis del binarismo y la visibilidad de sexualidades periféricas que, dentro de un acto político, procuran el derecho tanto a la igualdad como a la diferencia. Para ello, los argumentos, tesis y la conclusión pretenden comprobar que, más allá de estas incorporaciones y adscripciones a los temas del LGTBIQ+, estas nuevas propuestas estéticas están encaminadas hacia la construcción y la apertura de una sociedad incluyente que sobrepase el límite genérico y posibilite la asunción de la diferencia en todas sus dimensiones.

Bajo el título Territorio y voluntad comunitaria, la editorial Aula de Hu- manidades, de Bogotá, publicó en 2021 el trabajo de investigación doc- toral de Rodrigo Escobar-Holguín: “El ordenamiento territorial como acto volitivo comunitario. Un enfoque fenomenológico”, sustentado en junio de 2019, como requisito para optar al título de doctor en Filosofía por la Universidad del Valle en Cali, Colombia. La tesis fue dirigida por el profesor Julio César Vargas Bejarano y el jurado evaluador estuvo compuesto por los profesores Ana Patricia No- guera, Javier San Martín y Esteban Marín Ávila.

This study aimed to estimate the bioelectricity production process using a vinasse solution through the application of Plackett–Burman and Box–Behnken designs. An electrochemical cell was constructed using Arduino to measure the potential difference between an anode and cathode immersed in a vinasse solution, which is a byproduct of wine production containing organic compounds and ions that undergo redox reactions. The Plackett–Burman design identified the most influential variables among eight previously selected (concentration of the electrolyte, pH, temperature, stirring, addition of NaCl, yeast dose and electrode:solution ratio). The results showed that the most influencing variables were the vinasse concentration and stirring and a peak of 306 mV could be observed for a 100 mL experiment. The third most influential variable regarding the process was NaCl addition, which showed its high influence at larger times. Based on these results, the Box–Behnken design was used to determine the possible ranges of variation of the independent variables (vinasse concentration, stirring and NaCl dose) to maximize the bioelectricity production. Therefore, with the combination of the intermediate concentrated vinasse (1:3 v/v ratio) and stirring, a peak of 431.1 mV could be observed when adding 2% NaCl after 15 min of the experiment. In what concerns the instant bioelectricity, measured after 1 min of the experiment, values up to 437.9 mV could be observed although yeast and/or NaCl are necessary at short times. This study provides insights into the bioelectricity production process from vinasse, contributing to the understanding and potential for sustainable energy generation.

Systems engineering plays a key role in the naval sector, focusing on how to design, integrate, and manage complex systems throughout their life cycle; it is therefore difficult to conceive functional warships without it. To this end, specialized information systems for logistical support and the sustainability of material solutions are essential to ensure proper provisioning and to know the operational status of the frigate. However, based on an architecture composed of a set of logistics applications, this information system may require highly qualified operators with a deep knowledge of the behavior of onboard systems to manage it properly. In this regard, failure detection systems have been postulated as one of the main cutting-edge methods to address the challenge, employing intelligent techniques for observing anomalies in the normal behavior of systems without the need for expert knowledge. In this paper, the study is concerned to the scope of the Spanish navy, where a complex information system structure is responsible for ensuring the correct maintenance and provisioning of the vessels. In such context, we hereby suggest a comparison between different one-class techniques, such as statistical models, geometric boundaries, or dimensional reduction to face anomaly detection in specific subsystems of a warship, with the prospect of applying it to the whole ship.

Thermal comfort is essential when wearing a postural-corrective garment. Discomfort of any kind may deter regular use and prolong user recovery time. The objective of this work is therefore to optimize a new compound that can alter the temperature of orthopedic insoles, thereby improving the thermal comfort for the user. Its novelty is a resin composite that contains a thermoregulatory Phase-Change Material (PCM). An experimental design was used to optimize the proportions of PCM, epoxy resin, and thickener in the composite and its effects. A Box–Behnken factor design was applied to each compound to establish the optimal proportions of all three substances. The dependent variables were the Shore A and D hardness tests and thermogravimetric heat-exchange measurements. As was foreseeable, the influence of the PCM on the thermal absorption levels of the compound was quantifiable and could be determined from the results of the factor design. Likewise, compound hardness was determined by resin type and resin-PCM interactions, so the quantity of PCM also had some influence on the mechanical properties of the composite. Both the durability and the flexibility of the final product complied with current standards for orthopedic insoles.

Low Earth orbit (LEO) satellite constellations are increasingly gaining attention as future global Internet providers. At the same time, named data networking (NDN) is a new data-centric architecture that has been recently proposed to replace the classic TCP/IP architecture since it is particularly well suited to the most common usage of the Internet nowadays as a content delivery network. Certainly, the use of NDN is especially convenient in highly dynamic network environments, such as those of next LEO constellations incorporating inter-satellite links (ISL). Among other native facilities, such as inbuilt security, NDN readily supports the mobility of clients, thus helping to overcome one of the main problems raised in LEO satellite networks. Moreover, thanks to a stateful forwarding plane with support for multicast transmission and inbuilt data caches, NDN is also able to provide a more efficient usage of the installed transmission capacity. In this paper, we propose a new location-based forwarding strategy for LEO satellite networks that takes advantage of the knowledge of the relative position of the satellites and the grid structure formed by the ISLs to perform the forwarding of NDN packets. So, forwarding at each node is done using only local information (node and destination locations), without the need of interchanging information between nodes, as is the case with conventional routing protocols. Using simulation, we show that the proposed forwarding strategy is a good candidate to promote the efficient and effective future use of the NDN architecture in LEO satellite networks.

Concern about the harmful effects that ultraviolet (UV) rays have on the skin of people who are routinely exposed to solar radiation has driven the industry of skin protection creams, sunglasses and clothing. Spanish Navy personnel are subject to different levels of exposure depending on their rank and function. The objective of this research is to analyze the behavioral variables associated to the effects on the skin caused by UV rays, denoted by the combined effects of perceived susceptibility and perceived severity, on their decision to purchase and wear uniforms with UV protection. A confirmatory analysis using a structural equation modeling (SEM) was performed on a sample of 100 respondents. The model results revealed a strong mediating characteristic of the intention to use, variable associated with the exogenous variables. Attitude towards the use of clothing and social influence, as well as the exogenous variable clothing action planning, on the sun protective clothing use during tactical maneuvers. These relationships were significant with p-values close to zero. However, exogenous variables related to perceived susceptibility and perceived severity in exposure to sunlight did not represent a significant influence when mediated by self-efficacy in use. The results revealed the consequence of awareness about the importance of protecting oneself and the influence that usage habits can have on the military with respect to the decision to purchase uniforms with UV protection.

Natural illumination has an important place in home automation applications. Among other advantages, it contributes to better visual health, energy savings, and lower CO2 emissions. Therefore, it is important to measure illuminance in the most accurate and cost-effective way. This work compares several low-cost commercial sensors (VEML 7700, TSL2591, and OPT3001) with a professional one (ML-020S-O), all of them installed outdoors. In addition, a platform based on the Internet of Things technology was designed and deployed as a centralized point of data collection and processing. Summer months have been chosen for the comparison. This is the most adverse situation for low-cost sensors since they are designed for indoor use, and their operating range is lower than the maximum reached by sunlight. The solar illuminance was recorded every minute. As expected, the obtained bias depends on the solar height. This can reach 60% in the worst circumstances, although most of the time, its value stays below 40%. The positive side lies in the good precision of the recordings. This systematic deviation makes it susceptible to mathematical correction. Therefore, the incorporation of more sensors and data that can help the global improvement of the precision and accuracy of this low-cost system is left as a future line of improvement.

Objective: The objective of this study was to compare the ICDAS-II caries status and caries-related factors among children from rural and urban schools in Pasto, Colombia. Materials and Methods: The study included 120 children (4 - 6 year- old children) from rural (privileged) and urban (unprivileged) schools. Caries was evaluated using the ICDAS-II criteria. A survey about the factors related to the presence of caries was applied. Chi-square and Fisher’s tests were used to assess the differences in each study variable between the two groups. A Mann–Whitney U test was used to compare the number of teeth, per ICDAS-II category, between the groups. Negative binomial regression was used to estimate the percentage change in the mean number of teeth, per ICDAS-II category, among the rural and urban students. Results: Significant differences were found between the rural and urban students for the ICDAS-II 0 and 3-6 categories (p

Braking time in a moving train at standard speeds has become a critical variable that increasingly concerns the industry. The present paper discusses the possible option of temperature variation to cut down the response time of the whole pneumatic braking system in a train installation. A pneumatic system, considered equivalent to the system existing in a real train, was experimentally analyzed to account for the time and characteristics of a sonic pressure wave moving in the pipes. The available system behavior was compared for two different air temperatures. The obtained results point to a relevant temperature effect on the pressure wave transmission, which may promote time or distance shortening in a standard braking process. Although in the experimental campaign only two initial temperatures could be set, the study shows a possible research path for future improvements. A parallel theoretical calculation corrected by the effect of the relevant elements in the pipes was performed to allow a comparison with the experiments.

The present research aims to understand the challenges faced by a Colombian city in the context of multidimensional risk scenarios, given the existing demographic and socio-economic conditions and local perspectives and perceptions regarding socio-environmental risks. The research was undertaken in the city of Barranquilla, northern Colombia. A survey was designed to analyze (1) the general socio-economic and vulnerability conditions of a communities’ sample, (2) information related to hazards and disaster risk in their neighbourhoods, and (3) information on actions to mitigate risk. Three hundred and ninety-one people were surveyed. Likert scale and Pearson's Chi-square test and descriptive, inferential statistical methods, regression models, and the Mann–Whitney U test were used to process the results. Respondents lived, in general, under precarious socio-economic conditions (such as low income or lack of infrastructure and others). Given socio-environmental constraints, the research revealed that hazards such as urban stream flooding and robbery were the most negatively associated with the respondent’s quality of life. Regarding the actions to avoid losses, 84% of respondents had not implemented any preventive action. Respondents also have low awareness of the need to implement risk prevention actions. Social risks and the configuration of anthropic hazards stand out as principal centres for concern.

The issue of energy balancing in Wireless Sensor Networks is a pivotal one, crucial in their deployment. This problem can be subdivided in three areas: (i) energy conservation techniques, usually implying minimizing the cost of communication at the nodes since it is known that the radio is the biggest consumer of the available energy; (ii) energy-harvesting techniques, converting energy from not full-time available environmental sources and usually storing it; and (iii) energy transfer techniques, sharing energy resources from one node (either specialized or not) to another one. In this article, we survey the main contributions in these three areas and identify the main trending topics in recent research. A discussion and some future directions are also included.

This data article employs the Fuzzy Analytic Hierarchy Process (FAHP) to perform the project risk assessment in a phase of the construction of a large hydroelectric project. The list of service packs and risk events was extracted from in-depth interviews and content analysis with experts. Such qualitative data were used to identify the relevant service pack and risk event indicators for two groups – the owner's and the builder's representatives – required to specify the model. FAHP was used to calculate the relative importance of such indicators in two stages. First the relevance of the service packs was measured through paired comparisons and then weighted. Next, the relevance of the risk events associated with each service pack was assessed through the same method. A complete method of calculation for one of the respondents is presented. At the end, the average weights for the risk events of the two groups are calculated. For further information it is recommended to read the article entitled “Multi-criteria risk assessment: Case study of a large hydroelectric project” (Ribas et al., 2019).

Current protocols for gilts recommend the deposit of multiple semen doses in the cervix each 12–24 h after estrus detection. Our objectives were: (1) to determine the effect of buserelin and a single fixed-time artificial insemination using the new post-cervical artificial insemination technique (FTAI-PCAI) on reproductive and productive performance in gilts, and (2) to compare this protocol with conventional estrus detection and double PCAI without hormonal induction. In the control group (C; n = 240), gilts were inseminated twice (8 and 12 h from estrus onset). Gilts in the treatment group (T; n = 226) received buserelin (10 μg, intramuscular) 120 h after altrenogest treatment (18 d) and one single PCAI 30–33 h after buserelin administration. The groups did not differ in reproductive and production performance (p > 0.05). The T group showed greater piglet birth weight and shorter estrus duration (p < 0.001). Delivery batch length differed significantly depending on the season (p < 0.05); the shortest length corresponded to autumn. Both groups only differed significantly in spring (p = 0.018), with a shorter length in the T group. This new FTAI-PCAI protocol with buserelin is recommended in gilts, helping with optimization of genetic diffusion, boars, and semen doses.

Wind energy harvesting technology is one of the most popular power sources for wireless sensor networks. However, given its irregular nature, wind energy availability experiences significant variations and, therefore, wind-powered devices need reliable forecasting models to effectively adjust their energy consumption to the dynamics of energy harvesting. On the other hand, resource-constrained devices with limited hardware capacities (such as sensor nodes) must resort to forecasting schemes of low complexity for their predictions in order to avoid squandering their scarce power and computing capabilities. In this paper, we present a new efficient ARIMA-based forecasting model for predicting wind speed at short-term horizons. The performance results obtained using real data sets show that the proposed ARIMA model can be an excellent choice for wind-powered sensor nodes due to its potential for achieving accurate enough predictions with very low computational burden and memory overhead. In addition, it is very simple to setup, since it can dynamically adapt to varying wind conditions and locations without requiring any particular reconfiguration or previous data training phase for each different scenario.

Airports, broadly spread world-wide, present continuously increasing energy demands for heating and cooling purposes. Relocatable facilities within them could be built on recycling shipping containers provided with the right insulation layer, to reduce the outstanding consumption of the heating, ventilation and air conditioning systems (HVAC). This research focuses on studying the effect of added insulation on the thermal performance of a construction in the scope of an airport facility, based on a recycled shipping container. Passive heating and cooling insulation strategies have shown good results in terms of energy savings. A series of simulations were performed along six different Spanish airports locations, selected to represent several climate conditions. Temperature evolution inside the container, and energy demands of the HVAC system were obtained to show that the insulation provided by phase change materials (PCM) is performing better than traditional insulation, or a raw container. Although there are slight behavior differences according to the climate, PCM can increase inside temperature even with no HVAC under certain circumstances.

Daylight availability knowledge is the first step for an energetic and visually efficient building and city design. It can be estimated with the Vertical Sky Component (VSC), which is defined as the ratio of the vertical diffuse illuminance over the unobstructed horizontal diffuse illuminance, simultaneously measured at the same point. These illuminance magnitudes are obtained from luxmeter measurements but these data are scarce. Alternatively, VSC can be obtained from prior knowledge of the sky illuminance distribution, which can be measured with a sky scanner device or by reference to the CIE (Commission Internationale de L’Éclairage) Standard classification for homogeneous skies. Both approaches are compared in this study. The coherence of the results obtained for the four cardinal orientations are analyzed by applying classical statistical parameters and luxmeter measurements as references for the results. The measurement campaign was completed between September 2016 and January 2019 in Burgos (Spain), as representative case study and specific contribution of this work. It was observed that the VSC values were higher than 100 in many cases: 21.94% for the south- and 33.6% for the east-facing vertical surfaces. The study highlights the good daylighting conditions in Burgos, mainly due to the predominance of clear skies over much of the year. This fact implies high daylight availability that, with efficient city planning and building design, could potentially lead reduction energy consumption of buildings, improvements in visual comfort, and the well-being of occupants.

Sunlight is one of the most frequently used ambient energy sources for energy harvesting in wireless sensor networks. Although virtually unlimited, solar radiation experiences significant variations depending on the weather, the season, and the time of day, so solar-powered nodes commonly employ solar prediction models to effectively adapt their energy demands to harvesting dynamics. We present in this paper a novel energy prediction model that makes use of the altitude angle of the sun at different times of day to predict future solar energy availability. Unlike most of the state-of-the-art predictors that use past energy observations to make predictions, our model does not require one to maintain local energy harvesting patterns of past days. Performance evaluation shows that our scheme is able to provide accurate predictions for arbitrary forecasting horizons by performing just a few low complexity operations. Moreover, our proposal is extremely simple to set up since it does not require any particular tuning for each different scenario or location.

This manuscript integrates the experimental findings of recently developed epoxy-phase change material (PCM) formulations with modeling efforts aimed to determine the energy demands and savings derived from their use. The basic PCM system employed was composed of an epoxy resin, a thickening agent, and nonadecane, where the latter was the hydrocarbon undergoing the phase transformation. Carbon nanofibers (CNF) and boron nitride (BN) particulates were used as heat flow enhancers. The thermal conductivities, densities, and latent heat determined in laboratory settings were introduced in a model that calculated, using EnergyPlus software, the energy demands, savings and temperature profiles of the interior and the walls of a shelter for six different locations on Earth. A shipping container was utilized as exemplary dwelling. Results indicated that all the epoxy-PCM formulations had a positive impact on the total energy savings (between 16% and 23%) for the locations selected. The use of CNF and BN showed an increase in performance when compared with the formulation with no thermal filler additives. The formulations selected showed great potential to reduce the energy demands, increase savings, and result in more adequate temperatures for living and storage spaces applications.

Se evaluó un sistema de tratamiento para agua lluvia cosechada en los techos de la Universidad Libre, sede Bosque Popular empleando elementos lignocelulósicos mediante dos filtros de flujo descendente con lecho profundo. Uno que consta de luffa cylindrica como soporte combinado con cascarilla de arroz como medio filtrante y otro que solo funcionó con cascarilla de arroz como medio filtrante. La eficiencia del tratamiento se evaluó a través de análisis físicos, químicos y biológicos como pH, turbiedad, sólidos disueltos totales, sólidos suspendidos totales, DQO y coliformes para un período de 10 días. Algunos de estos parámetros no mejoraron con el sistema en el período de prueba. Se observó además la ausencia de alcalinidad y dureza, lo que puede permitir el uso de esta agua en procesos diferentes al de consumo humano.

Este artículo describe una herra mienta de simulación bajo el en torno de Matlab®, que puede ser utilizada para estimar la auton omía de un vehículo con baterías o híbrido con pila de combustible y bater ías. El modelo es función de variables mecánicas y físicas que dependerán no solo del propio vehículo sino también del terreno. Su uso es extendido para recorridos obtenidos mediante dispositivos GPS y para ciclos estándar. Pueden obtenerse diferentes variables de salid a tales como: el consumo de hidrógeno y batería, el nivel hidró geno, el estado de carga de la batería, la potencia consumida, la producción de energía por parte de la pila, el máximo alcance del vehículo y el máximo número de ciclos finalizados. La simulación de rutas reales pro porciona una buena aproximación de la velocidad del vehículo pa ra usos, en lugar de utilizar ciclos de c onducción estándar, obteniendo así aproximaciones bas tante arbitrarias para una ruta real.

We present new records of bats for Colombia, including the first documented records of Glyphonycteris daviesi for the country, collected in the savanna ecosystems from the Orinoco Llanos, and a new record of G. silvestris from the inter-Andean valley of Magdalena River that confirms its presence in this region of the country.

Humedales artificiales de flujo subsuperficial fueron evaluados con el fin de establecer su aplicabilidad al tratamiento de aguas residuales domésticas de la Universidad Libre, sede Bosque Popular. Dos humedales a escala banco fueron construidos en acrílico transparente, uno plantado con especies típicas de humedales naturales en Bogotá, y una unidad control sin plantar. El seguimiento se realizó durante un período de 2 meses, ejecutando los respectivos análisis para determinar la disminución de materia orgánica, sólidos suspendidos totales, y fósforo y nitrógeno, entre otros parámetros físicos y químicos. Se encontró que si bien, no existe una diferencia significativa entre los parámetros físicos determinados para el humedal con y sin plantas, este tipo de sistemas son bastante efectivos para remover carga orgánica, puesto que más del 60% de ella fue removida y para nitrógeno amoniacal se llegó a remociones de más del 90%; además de que el movimiento del agua y el contacto de la superficie del humedal con el oxígeno del aire, permite el intercambio de gases de una manera sencilla y efectiva como se ve reflejado en el incremento de oxígeno disuelto

Composite materials have great potential for growth due to their excellent properties and their multiple applications. The study of the thermal properties of the new composites resulting from the combination of epoxy resin and phase change materials (PCM), as well as thickening agents and thermally conductive compounds, was the objective of this work. For this purpose, different samples were manufactured by combining epoxy resins, organic PCMs (paraffins), and aluminum particles. Several properties were analyzed: thermal behavior (by differential scanning calorimetry technique), hardness, etc. To carry out this analysis, parameters of PCM quantity and metallic particles in the composition were varied. The results showed that the epoxy resin acted as a matrix containing the rest of the components and encapsulating the PCM. The organic PCM showed reversibility when subjected to multiple cycles. The enthalpy of the organic PCM−resin compound varied linearly according to the PCM content in the sample. For the content of this material in the samples to reach up to 40%, the use of thickening agents was necessary. The use of metallic particles improved the conductivity of the composites even while maintaining a low percentage by weight of metallic particles. Thermal simulations of the composite in bottom-coating a photovoltaic panel estimated a reduction of several degrees Celsius, showing the potential use of the PCM−epoxy resin for improving the energy production of such panels.

Aquest articles intenta descriure el que va succeir la nit del 26 al 27 de setembre de 2014, quan 43 estudiants de magisteri van desaparèixer a l’estat mexicà de Guerrero, així com copsar el sentit d’aquest fet com a absència de pau social al país. L’enfocament adoptat serà des de l’ètica, per la qual cosa s’hi emprarà el mètode del discerniment ètic per descriure el que va succeir.

Se investigaron cocaína y marihuana en meconio de neonatos nacidos en la Maternidad Provincial de la Ciudad de Córdoba y se relacionaron los resultados con las semanas de gestación y los pesos al nacer. Las determinaciones se realizaron utilizando inmunoensayo y cromatografía gaseosa-espectrometría de masas. Se analizaron 48 muestras de meconio recolectadas durante un año (2007-2008). De los 48 meconios analizados, 17 correspondieron a neonatos masculinos y 31 a neonatos femeninos. Se procesaron en paralelo 15 muestras de meconio como controles normales (niños no expuestos a drogas) seleccionados por historia clínica y controles prenatales. De las 48 muestras de meconio 13 fueron positivas para cocaína y/o marihuana. El peso y las semanas de gestación de los neonatos cuyas muestras fueron positivas se compararon frente a un grupo control normal, hallándose mayores diferencias estadísticamente significativas (α=0,05 - pWe investigated cocaine and marijuana in meconium of newborns attended at the Hospital Materno Provincial of Córdoba City and the results were correlated with birthweight and weeks of pregnancy. The samples were analyzed using immunoassay (FPIA) and gas chromatography-mass spectrometry (GC-MS) for confirmation. Forty eight samples of meconium were collected during one year period (2007-2008). Of the 48 samples screened, 17 correspond to masculine sex and 31 to feminine. Fifteen samples of meconium from normal newborns (newborns not exposed to drugs) selected by maternal self report, pregnancy controls were processed as control group. The results obtained in 48 samples of meconium showed 13 cases tested positive for cocaine and/or marijuana. Birth weight and weeks of gestation of newborn with positive sample results were compared with a control group. A statistically significant difference (α= 0.05 - p

Se evaluó un sistema de tratamiento para agua lluvia cosechada en los techos de la Universidad Libre, sede Bosque Popular empleando elementos lignocelulósicos mediante dos filtros de flujo descendente con lecho profundo. Uno que consta de luffa cylindrica como soporte combinado con cascarilla de arroz como medio filtrante y otro que solo funcionó con cascarilla de arroz como medio filtrante. La eficiencia del tratamiento se evaluó a través de análisis físicos, químicos y biológicos como pH, turbiedad, sólidos disueltos totales, sólidos suspendidos totales, DQO y coliformes para un período de 10 días. Algunos de estos parámetros no mejoraron con el sistema en el período de prueba. Se observó además la ausencia de alcalinidad y dureza, lo que puede permitir el uso de esta agua en procesos diferentes al de consumo humano.

La Economía de la Empresa es una parcela o rama del saber de la Ciencia Económica, cuya finalidad es la de estudiar y dar respuesta a los problemas concretos que se plantean en el seno de la empresa. Su configuración como disciplina autónoma o sustantiva, si bien experimentó un considerable avance durante la segunda mitad del siglo XIX, no se produce en realidad hasta bien avanzado el siglo XX. Este trabajo pretende, en memoria y homenaje al Profesor Emilio Soldevilla, esbozar la presencia y evolución de la Economía de la Empresa en los planes de estudio de las universidades españolas.

La hipersensibilidad en tejido dentario, es una patología que día a día aumenta su frecuencia en población adulta, quizás no es una causa primaria de consulta odontológica pero se podría clasificar como secundaria, debido a que es de tipo multifactorial. En la actualidad toda la información sobre la hipersensibilidad dentinal es reportada de la experiencia clínica pero no de estudios clínicos reales los cuales todavía son débiles o ausentes; en cuanto al tratamiento de esta, se evidencia que el primer paso es modificar la dieta y crear hábitos mediante el uso de sustancias para tal fin como una buena alternativa. Debido a esto se hace necesaria la compilación de las diferentes causas y la creación de un protocolo de manejo clínico ante la presencia de esta dolencia; también es importante prevenirla, por eso se percibe la necesidad de crear medidas de prevención para aplicarlas en la consulta odontológica.