Resumen. La mojarra (Eucinostomus currani) es un recurso importante de subsistencia en mercados locales de Ecuador. Sin embargo, poco es sabido sobre la historia de vida temprana y la biología reproductiva de esta especie. En 2016 y 2017, se recolectaron larvas de E. currani en 3 playas arenosas en el Golfo de Guayaquil, Ecuador, y se identificaron usando códigos de barras de ADN. La longitud estándar de las larvas osciló entre 4.00 y 15.78 mm. También recolectamos otolitos para comprender mejor la historia de vida temprana de E. currani. Los otolitos se usaron para estimar la edad, la tasa de crecimiento de la población (±EE), las fechas de eclosión y la época reproductiva. En promedio, la edad de los peces fue de 16.5 ± 4.5 días, mientras que la tasa de crecimiento promedio fue de 0.70 ± 0.05 y 0.22 ± 0.16 mm por día en marzo y mayo, respectivamente. En el Golfo de Guayaquil, la mayoría de las fechas de eclosión y la actividad reproductiva presunta de E. currani ocurrió durante la época húmeda (diciembre-abril) cuando aguas más calidas prevalecieron. Hasta donde tenemos conocimiento, este es el primer estudio que estima las fechas de eclosión y la tasa de crecimiento larval para una especie de la familia Gerreidae en el Océano Pacífico.

Abstract. The flagfin mojarra (Eucinostomus currani) is an important subsistence fishery resource in local Ecuadorian markets; however, very little is known about the early life history and reproductive biology of this species. In 2016 and 2017, E. currani larvae were collected at 3 sandy beaches in the Gulf of Guayaquil, Ecuador, and identified using DNA barcoding. Standard lengths ranged from 4.00-15.78 mm. We also collected otoliths to better understand the early life history of E. currani. Otoliths were used to estimate the age, population growth rate (±SE), hatch dates, and reproductive period. On average, the fish were 16.5 ± 4.5 days old, while the average growth rate was 0.70 ± 0.05 and 0.22 ± 0.16 mm per day in March and May, respectively. In the Gulf of Guayaquil, most hatch dates and the presumed reproductive activity of E. currani occurred during the wet season (December-April) when warmer water prevailed. To our knowledge, this is the first study to estimate the hatch dates and larval growth rate for a species of the family Gerreidae in the Pacific Ocean.

ABSTRACT Social technology is based around three axes: community, environmental protection and economic solidarity. The páramo itself is a vital ecosystem for water regulation as it is the source of water supplies for human consumption and performance of economic activities. This article intends to identify the limitations to apply social technology to the protection of the páramo in the central highlands of Ecuador, where processes of self-management, empowerment, participation, agreement-making, cooperation and pursuit for collective welfare have been observed. The methodology is quantitative within the framework of discourse analysis. The results show that, in order to reach a large agreement for the protection and recovery of the páramo, involving all of the communities settled in the area, it is necessary to overcome limitations mostly related to the lacking attention by the government in regards to basic utilities, management plans for conservation areas and studies for economic alternatives allowing communities to subsist in the lower zones, compromising not to extend their agricultural borders further into the highlands. This information helps strengthen natural resource management from a new perspective.

RESUMO A tecnologia social baseia-se em três eixos: a comunidade, o cuidado ambiental e a solidariedade econômica. O páramo é um ecossistema vital para a regulação hídrica pois ele fornece agua para o consumo humano e a realização de atividades económicas. Esse artigo focou-se na identificação das limitações para aplicar os fundamentos da tecnologia social para a proteção do páramo, situado na Sierra central de Equador, sítio onde pode-se observar processos de autogestão, empoeiramento, participação, efetuação de acordos, cooperação e procuração de um bem-estar coletivo. A metodologia é qualitativa, dentro do contexto da análise do discurso. Os resultados mostram que, para ter um acordo grande para a proteção e recuperação do páramo, com todas as comunidades estabelecidas na zona, é necessário vencer limitações relacionadas principalmente à falta de atenção do governo em relação à serviços básicos, planes de gestão de áreas de conservação e estudo de alternativas económicas que permitam que as comunidades possam subsistir nas zonas baixas, e comprometer-se a não estender a fronteira agrícola em direção às zonas altas. Essa informação contribui a fortalecer a gestão de recursos naturais com uma nova perspectiva.

RESUMEN La tecnología social se fundamenta en tres ejes: la comunidad, el cuidado ambiental y la solidaridad económica. Por su parte, el páramo es un ecosistema vital en la regulación hídrica porque sustenta el suministro de agua para consumo humano y el desarrollo de actividades económicas. Este artículo se centra en identificar las limitaciones para aplicar los fundamentos de la tecnología social en la protección del páramo, ubicado en la Sierra central del Ecuador, lugar donde se observan procesos de autogestión, empoderamiento, participación, logro de acuerdos, cooperación y búsqueda del bienestar colectivo. La metodología es cualitativa, en el marco del análisis del discurso. Los resultados muestran que, para que exista un gran acuerdo de protección y recuperación del páramo, entre todas las comunidades asentadas en esta zona, es necesario vencer limitaciones relacionadas, principalmente, con la falta de atención por parte del gobierno en temas de servicios básicos, planes de manejo para áreas de conservación y estudio de alternativas económicas que permitan a las comunidades subsistir en las zonas bajas y comprometerse a no ampliar la frontera agrícola hacia zonas altas. Esta información contribuye a fortalecer la gestión de recursos naturales desde una nueva perspectiva.

Abstract: Environmental pollution from transportation has been a fundamental challenge for humanity throughout history, with conventional fuels contributing significantly to environmental degradation. This project seeks to suppress pollution and reduce noise generated by motorcycle taxis, whether for personal and/or private use. The main objective of the research work was to implement an electrolyzer in the combustion system of a motorcycle taxi to suppress environmental pollution and reduce noise. Methods included vehicle preparation, electrolyzer installation, battery adjustment, hydrogen generation, emissions measurement, safety, and data collection. As a result, the electrolyzer was implemented in the single-cylinder motorcycle taxi; The noise limit allowed at work in Peru is 85 dB, which is equivalent to 100 % noise at most; When using gasoline, a value of 76.4 dB was obtained, equivalent to 89.88 % noise, and when using hydrogen, a value of 71.7 dB was obtained, equivalent to 84.35 % noise, therefore, the total noise reduction was 4.70 dB (5.53 %) than established. The discussion highlighted that hydrogen is a clean fuel, with zero emissions and only emitting water vapor instead of polluting gases (5). The conclusion highlights the critical importance of the research, supported by the total reduction of 5.53 % of noise with this new technology and in turn external sources support that using hydrogen produced a smoother and quieter combustion; Regarding the useful life of the engine, due to the cleaner and more efficient combustion, the accumulation of waste was reduced, which benefits reducing the wear of internal components and the need for costly maintenance.

Resumen: La contaminación ambiental derivada del transporte ha sido un desafío fundamental para la humanidad a lo largo de la historia, con los combustibles convencionales contribuyendo significativamente a la degradación ambiental. Este proyecto busca suprimir la contaminación y reducir el ruido generada por mototaxis, ya sean de uso personal y/o privado. El trabajo de investigación tuvo como objetivo principal implementar un electrolizador en el sistema de combustión de un mototaxi para suprimir la contaminación ambiental y reducir el ruido. Los métodos incluyeron la preparación del vehículo, instalación del electrolizador, ajuste de la batería, generación de hidrógeno, medición de emisiones, seguridad y recolección de datos. Como resultado, se logró implementar el electrolizador en el mototaxi monocilíndrico; el límite de ruido permitido en el trabajo en el Perú es de 85 dB, que equivalen el 100 % de ruido como máximo; al utilizar gasolina se obtuvo un valor de 76.4 dB equivalentes a 89.88 % de ruido y al usar hidrógeno se obtuvo un valor de 71.7 dB siendo el 84.35 % de ruido, por lo tanto, la reducción total de ruido fue de 4.70 dB (5.53%) de lo establecido. La discusión destacó que el hidrógeno es un combustible limpio, con nulas emisiones y solo emitiendo vapor de agua en vez de gases contaminantes (5). La conclusión subraya la importancia crítica de la investigación, respaldada por la reducción total del 5.53 % de ruido con esta nueva tecnología y a su vez fuentes externas apoyan, que el utilizar hidrógeno produjo una combustión más suave y silenciosa. En cuanto a la vida útil del motor, la combustión más limpia y eficiente reduce la acumulación de residuos, lo que disminuye el desgaste de los componentes internos y la necesidad de mantenimientos costosos.

Resumen En zonas de clima árido y semiárido, la disponibilidad y la calidad del agua son factores críticos para el desarrollo de la agronomía. Para enfrentar el desafío, una alternativa para el aprovechamiento de este recurso es la implementación de técnicas eficientes y sostenibles como el uso de riego por goteo. El objetivo del trabajo fue analizar el comportamiento agronómico del centeno en condiciones desfavorables de agua y temperatura para determinar la efectividad de la estabilidad fenotípica en la Costa de Hermosillo, Sonora, México. Se sembraron dos genotipos de centeno bajo un diseño experimental de parcelas divididas (parcela grande: tres niveles de agua y parcela chica: dos genotipos de semillas obtenidas en ciclos diferentes). Se evaluaron las características agronómicas de la planta, las características fisicoquímicas del grano; y se determinó la significancia entre las distintas variables con un análisis de correlación. El análisis de varianza reveló efectos sobre la altura de la planta, el número de espigas y de granos, tamaño de grano, el peso de mil granos, rendimiento y contenido de proteína del centeno debido a los diferentes regímenes hídricos utilizados. Se obtuvieron entre 219-314 espigas por metro lineal, con tamaño de grano comercialmente aceptable (7.45-7.95 mm largo x 2.18-2.40 mm ancho). También se observaron valores de rendimiento altos (1.72-3.11 t ha-1), así como un excelente contenido de proteína (20.3-22.8%). Estos resultados demuestran que el centeno es un cereal versátil que se adapta a condiciones ambientales adversas como disminución en la cantidad de agua de riego y temperaturas extremadamente altas.

Abstract In areas with arid and semi-arid climates, the availability and quality of water are critical factors for the development of agronomy. To face the challenge, an alternative for the use of this resource is the implementation of efficient and sustainable techniques such as the use of drip irrigation. The objective of the work was to analyze the agronomic behavior of rye under unfavorable water and temperature conditions to determine the effectiveness of phenotypic stability on La Costa de Hermosillo, Sonora, Mexico. Two rye genotypes were planted under a split plot experimental design (large plot: three water levels and small plot: two genotypes of seeds obtained in different cycles). The agronomic characteristics of the plant, the physicochemical characteristics of the grain were evaluated; and the significance between the different variables was determined with a correlation analysis. The analysis of variance revealed effects on plant height, number of spikes and grains, grain size, thousand grain weight, yield and protein content of rye due to the different water regimes used. Between 219-314 spikes per linear meter were obtained, with a commercially acceptable grain size (7.45-7.95 mm long x 2.18-2.40 mm wide). High yield values (1.72-3.11 t ha-1) were also observed, as well as excellent protein content (20.3-22.8%). These results demonstrate that rye is a versatile cereal that adapts to adverse environmental conditions such as a decrease in the amount of irrigation water and extremely high temperatures.

In the context of South Africa's water scarcity, desalination has emerged as a possible solution for coastal areas. However, the quality of the intake water for desalination is often problematic, prompting the need for pre-treatment. The aim of this study was to conduct a comparative environmental life cycle assessment (LCA) on 4 seawater filtration systems intended for the pre-treatment of a reverse osmosis desalination project. These systems were implemented in a pilot trial and are based on modern water treatment technologies, namely, granular filtration (pressure driven and gravity driven), dissolved air flotation (DAF), and ultrafiltration (UF). For all 4 systems, data were collected for both the construction and operation phases, and LCAs were performed, resulting in environmental scores that allow for comparison based on the pre-treatment of 1 kL of seawater of the same quality. The SimaPro LCA tool and the ReCiPe midpoint method were used and environmental scores were calculated for 18 impact categories, including climate change, acidification, toxicity, eutrophication, resource depletion, etc. This methodology also allowed the identification of the highest environmental burdens/scores within each system. The most significant finding is that local electricity consumption is responsible for the greatest proportion of environmental impacts. Thus, the systems consuming more energy for operating equipment such as blowers, pumps, and mixers were found to have the highest environmental burdens. Hence, the DAF system has the highest environmental scores for most impacts, followed by the single-phase gravity filtration system, then the two-phase partial pressure filtration system and finally the UF system. Therefore, focus should shift towards energy optimisation of process units, especially the rotary ones, as well as energy mitigation and recovery strategies. The use of renewable energy for pre-treatment should also be considered locally.

Abstract The marketing of microbial pesticides has increased exponentially in recent years. Almost 70 % of the products marketed use as active ingredient conidia of biocontrol fungi, and One of the most frequently used criteria to evaluate the quality of these products is conidial germination test, Specifically, this methodology is used to select and assess the viability and vigor of elite strains with biological potential. Some of the factors that influence conidial germination over time, include the selection of culture medium, temperature, incubation time, and the addition of germination synchronizing agents. The optimization for each elite strain allows the characterization of a microorganism behavior over time, ensuring its biological activity and effective management as a biological resource for commercial purposes. The main objective of this study was to identify the optimal conditions (culture media, incubation time, and synchronizing agent concentration) for the germination of three elite strains: Trichoderma koningiopsis (Th003), Lecanicillium lecanii (Vl026), and Metarhizium robertsii (Mt004), which are active ingredients in biopesticides. As a result, the optimal conditions selected are as follows: agar-water medium with 0.0003 % benomyl for Th003 with an incubation period of 18 hours, agar-water medium with 0.0003 % benomyl for Vl026 with an incubation period of 24 hours, and PDA agar supplemented with 0.0003 % benomyl for Mt004 with an incubation period of 18 hours. These conditions will allow a precise evaluation of the germination of the biological control agents ensuring over time their viability and vigor as active ingredients in biopesticides.

Resumen La comercialización de plaguicidas microbianos ha aumentado de manera exponencial en los últimos años. Casi el 70 % de los productos que se comercializan utilizan como principio activo conidios de hongos biocontroladores y uno de los criterios más utilizados para evaluar la calidad de estos productos es la prueba de germinación de conidios. Específicamente, se utiliza para la selección y la evaluación de la viabilidad y vigor de cepas élite con potencial biológico. Algunos de los factores que influyen en la germinación de los conidios incluye la selección del medio del cultivo, la temperatura, el tiempo de incubación y la adición de sustancias sincronizadoras de germinación. La optimización para cada cepa élite permite estimar el comportamiento del microorganismo, lo que garantizará su actividad biológica y eficacia, al ser un recurso biológico con fines comerciales. El objetivo de este trabajo fue seleccionar las condiciones óptimas (medios de cultivo, tiempo de incubación y concentración de sustancia sincronizadora) para la germinación de tres cepas élite Trichoderma koningiopsis (Th003), Lecanicillium lecanii (Vl026) y Metarhizium robertsii (Mt004), las cuales son principios activos de bioplaguicidas en proceso de comercialización. Como resultado se seleccionó el medio de cultivo de agar agua con benomil al 0,0003 % con un tiempo de lectura de 18 h para Th003 y de 24 h para Vl026. Para la cepa Mt004, el medio de cultivo que favoreció la germinación sincrónica de los conidios fue agar PDA suplementado con benomil al 0,0003 % con un tiempo de lectura de 18 h. Estas condiciones permitirán a través del tiempo realizar una correcta evaluación de la germinación de los agentes de control biológico y garantizar su viabilidad y vigor como principio activo de bioplaguicidas.

Abstract The study of the freshwater-saltwater interface zone (FWSWI) is fundamental for the characterization of coastal aquifers and the evolution of freshwater reserves. In this work we study the factors that condition the dynamics of the IADAS in the locality of Pinamar. To carry out this task, a monitoring borehole was drilled on the coastal front, electrical conductivity (EC) profiling was performed, and continuous pressure, temperature and salinity sensors were installed. Information was collected from the tide gauge located in the town of Santa Teresita, while hydrometeorological data were obtained from a station located in the town of Pinamar. A correlation between high tide events and salinity, water level and temperature values were verified. The response times between the rise of the tide and the increase of the salinity are less than 8 hours, while the interval required to reach equilibrium again takes at least 2 days. Temperature variations are influenced by the prevailing climatic conditions at the time of the rising tide. The analysis of the relationship between storage variation and high tide events allows inferring that, when recharge events occur, there is a greater stability due to the increase of the hydraulic load on the IADAS. The study of IADAS behavior is an effective indicator for resource management.

Resumen El estudio de la zona de interfase agua dulce-agua salada (IADAS) resulta fundamental para la caracterización de acuíferos costeros y la evolución de las reservas de agua dulce. En este trabajo se estudian los factores que condicionan la dinámica de la IADAS en la localidad de Pinamar. Para llevar a cabo esta tarea se realizó una perforación de monitoreo sobre el frente costero, se realizaron perfilajes de conductividad eléctrica (CE) y se instalaron sensores continuos presión, temperatura y salinidad. Se recopiló información proveniente del mareógrafo ubicado en la localidad de Santa Teresita mientras que los datos hidrometeorológicos se obtuvieron a partir de estación ubicada en la localidad de Pinamar. Se verifica una correlación entre los eventos de pleamar y los valores de conductividad eléctrica, nivel hidráulico y temperatura. Los tiempos de respuesta entre el ascenso de la marea y el aumento de la salinidad se reconocen menos de 8 horas, en tanto que el intervalo requerido para alcanza nuevamente el equilibrio demora al menos 2 días. Las variaciones de la temperatura se encuentran influenciadas por las condiciones climáticas dominantes al momento del ascenso de la marea. El análisis de la relación entre la variación del almacenamiento y los eventos de pleamar permiten inferir que, cuando se producen eventos de recarga, existe una mayor estabilidad debido al incremento de la carga hidráulica sobre la IADAS. El estudio del comportamiento de la IADAS resulta un indicador eficaz para la gestión de los recursos hídricos en sectores costeros.

Resumo O noroeste pacífico da Costa Rica é uma região com uma estacionalidade no regime de chuvas muito marcada. Somado a essa sazonalidade, esta área da Costa Rica é propensa a fenômenos hidroclimáticos extremos como secas e inundações, por exemplo. A distribuição limitada de pluviômetros ou a falta de disponibilidade de informações relevantes fazem com que os dados complementares obtidos de satélites e suas respectivas reanálises sejam fundamentais para obter informações cruciais e, assim, embasar as ações de gestão dos recursos hídricos e suas repercussões nos ecossistemas, tanto naturais quanto produtivos. Para analisar os padrões de precipitação, foram analisadas as séries temporais de precipitação do produto CHIRPS para cinco ecorregiões delimitadas na Área de Conservação Guanacaste, no Pacífico noroeste da Costa Rica. Estas curvas foram correlacionadas com as séries temporais das regiões de monitoramento da temperatura superficial do mar nas regiões Niño 1.2, Niño 3, Niño 3.4 e Niño 4. Todas as ecorregiões analisadas correlacionaram de forma negativa e forte com a região do Niño 1.2, com valores de R entre -0.72 e -0.74. Além disso, foi detectado um atraso na curva do Niño 4 de quatro a cinco meses, em relação à curva da região Niño 1.2. O estudo sugere que a anomalia do El Niño 4, com um desfasamento de aproximadamente 4 a 5 meses, pode ser utilizada como indicador de possíveis impactos nos padrões de precipitação nas diferentes ecorregiões estudadas. Este tempo é suficiente para planejar ações, especialmente no setor agroprodutivo. Neste trabalho, é demonstrado o potencial de previsibilidade dos efeitos do fenômeno ENOS sobre o padrão de precipitação em áreas extensas e com certa homogeneidade ecossistêmica, como as ecorregiões na Área de Conservação Guanacaste.

Abstract The Pacific Northwest of Costa Rica is a region with marked seasonality in rainfall patterns. This area of Costa Rica is prone to extreme hydroclimatic phenomena such as droughts and floods. Due to the limited distribution of rainfall gauges and the unavailability of relevant information, complementary data obtained from satellites and their respective reanalyzes become imperative for acquiring crucial information. This information can support water resource management actions and their impacts on both natural and productive ecosystems. To analyze the precipitation patterns, we utilized the CHIRPS product’s precipitation time series for five ecoregions within the Guanacaste Conservation Area, located in the northwestern Pacific region of Costa Rica. These curves were strongly and negatively correlated with time series from sea surface temperature monitoring regions, including Niño 1.2, Niño 3, Niño 3.4, and Niño 4. All analyzed ecoregions exhibited strong negative correlations with the Niño 1.2 region, with correlation coefficients (R values) ranging between -0.72 to -0.74. Additionally, a lag of four to five months was observed in the Niño 4 curve compared to the Niño 1.2 region. This study suggests that the Niño 4 anomaly, with a lag of approximately 4 to 5 months, can serve as an indicator of possible impacts on precipitation patterns in different ecoregions. This provides sufficient time to plan actions, particularly within the agricultural sector. This study demonstrates the potential predictability of the effects of ENSO phenomenon on precipitation patterns for large areas with a certain eco-systemic homogeneity, such as the ecoregions in the Guanacaste Conservation Area.

Resumen El pacífico noroeste de Costa Rica es una región con una estacionalidad en el régimen de lluvias muy marcada. Sumado a dicha estacionalidad, esta área de Costa Rica es propensa a fenómenos hidroclimáticos extremos como sequías e inundaciones, por ejemplo. La escasa distribución de pluviómetros o bien, la no disponibilidad de información pertinente, hacen que los datos complementarios obtenidos de satélites y sus respectivas reanálisis, sean fundamentales para disponer de información crucial y así poder fundamentar las acciones de gestión del recurso hídrico y sus repercusiones en los ecosistemas, tanto naturales como productivos. Para analizar los patrones de precipitación, se analizaron las series de tiempo de precipitación del producto CHIRPS para cinco ecorregiones delimitadas en el Área de Conservación Guanacaste, en el Pacífico noroeste de Costa Rica. Estas curvas se correlacionaron con las series de tiempo de las regiones de monitoreo de la temperatura superficial del mar en las regiones Niño 1.2, Niño 3, Niño 3.4 y Niño 4. Todas las ecorregiones analizadas correlacionaron de forma negativa y fuertemente con la región del Niño 1.2, con valores de R entre -0.72 y -0.74. Por otra parte, se detectó un rezago en la curva de Niño 4 de cuatro a cinco meses, con la curva de la región Niño 1.2. El estudio sugiere que la anomalía del Niño 4, con un desfase de aproximadamente 4 a 5 meses, puede ser utilizada como indicador de posibles impactos en los patrones de precipitación en las diferentes ecorregiones estudiadas. Este tiempo es suficiente para planear acciones, sobre todo en el sector agroproductivo. En este trabajo se muestra el potencial de predictibilidad de los efectos del fenómeno ENOS sobre el patrón de la precipitación para áreas extensas y con cierta homogeneidad ecosistémica, como son las ecorregiones en el Área de Conservación Guanacaste.

Resumen Este artículo tiene como objetivo visibilizar el proceso de institucionalización, participación y conflicto social en torno a la gestión y manejo del agua potable en Costa Rica y estima como punto de arranque la segunda década del siglo XX, la cual discurre hacia la construcción de un eficaz modelo centralizado-descentralizado a partir de la década de 1970. Dicho proceso es analizado mediante la identificación de tres periodos históricos diferenciados mediante los cuales se pretende explicar el continuun, cambios, vacíos y conflictos de intereses del modelo de gestión del agua y su marco jurídico. El principal hallazgo es mostrar o poner en evidencia que la participación comunitaria bajo el mencionado modelo de gestión centralizado-descentralizado, aún vigente, ha garantizado la protección del agua para el bien común y parece ser, hasta ahora, una coraza legal-institucionalizada que impide la privatización del líquido vital. Se concluye que los intentos de privatizar la disponibilidad del agua potable con fines comerciales, no ha conseguido distorsionar la función social del Estado, la cual es proteger y garantizar el agua como un bien público.

Résumé Cet article vise à rendre visible le processus d'institutionnalisation, de participation et de conflit social lié à la gestion et à la distribution de l'eau potable au Costa Rica. Il prend comme point de départ la deuxième décennie du XXe siècle qui mène à la construction d'un modèle efficace centralisé-décentralisé à partir des années 1970. Ce processus est analysé en identifiant trois périodes historiques distinctes pour expliquer la continuité, les changements, les lacunes et les conflits d'intérêts du modèle de gestion de l'eau et de son cadre juridique. La découverte principale consiste à mettre en évidence que la participation communautaire sous le modèle de gestion centralisé-décentralisé, toujours en vigueur, a garanti la protection de l'eau pour le bien commun. Jusqu'à présent, il semble être une protection légale-institutionnalisée empêchant la privatisation du liquide vital. On a conclu que les tentatives de privatisation de l'accès à l'eau potable à des fins commerciales n'ont pas réussi à déformer la fonction sociale de l'État, qui est de protéger et de garantir l'eau en tant que bien public.

Abstract This article aims to shed light on the process of institutionalization, participation, and social conflict regarding the management of drinking water in Costa Rica. It takes the second decade of the 20th century as its starting point, leading towards the construction of an effective centralized-decentralized model from the 1970s. This process is analyzed by identifying three distinct historical periods, through which the article seeks to explain the continuum, changes, gaps, and conflicting interests of the water management model and its legal framework. The main finding highlights that community participation under the mentioned centralized-decentralized management model, still in force, has ensured the protection of water for the common good. It appears to be, up to now, a legally institutionalized shield preventing the privatization of this vital resource. The conclusion is that attempts to privatize the availability of drinking water for commercial purposes have not succeeded in distorting the social function of the State, which is to protect and guarantee water as a public good.

A comprehensive field investigation was conducted to enhance the productivity, profitability, and water use efficiency (WUE) of summer okra through the optimization of irrigation and nitrogen fertilizer application. The study involved 3 irrigation levels -0.75 Epan (pan evaporation) as I1, 1.00 Epan as I2, and 1.25 Epan as I3- as the main plot factors, and 4 nitrogen concentrations - 75% recommended nitrogen dose (RDN) as N1, 100% RDN as N2, 125% RDN as N3, and 150% RDN as N4- as the subplot variables. The results of the study revealed a significant influence of irrigation and nitrogen levels on various key parameters. Above-ground dry matter, yield, plant height, WUE, net returns, and benefit-to-cost ratio (B:C) exhibited an incremental trend with increasing irrigation and nitrogen levels, up to a certain threshold. Beyond this threshold, further increments in irrigation and nitrogen led to diminishing returns. The models developed for estimating crop yield, above-ground drv matter, plant height, WUE, net returns, and B:C demonstrated impressive accuracy, with high coefficients of determination (R²) and satisfactory precision. The optimized irrigation level (crop evapotranspiration, ET C) ranged from 418.39-441.23 mm. At the same time, the ideal nitrogen application rate was found to be in the range of 167.04-176.13 kg N/ha. These optimal conditions resulted in peak crop yield of 28 295 kg/ha, above-ground dry matter of 6 709.1 kg/ha, plant height of 66.3 cm, WUE of 5.26 kg/m³, B:C of 4.54, and net returns amounting to 441 133 INR/ha. In conclusion, the application of response surface methodology facilitated the identification of the impact of each factor on individual responses, as well as the determination of optimal conditions that simultaneously maximize multiple desirable outcomes. These findings hold significant promise for improving the cultivation of summer okra while optimizing resource use and economic returns.

Wetland delineation in South Africa incorporates soil form and soil wetness indicators, requiring formal soil classification and description of soil redox morphology. The current wetland definition used administratively in South Africa focuses on saturated (hydric) soil signatures within plant root zones. Saturated soil horizons deeper than plant root zones fall outside the 50 cm criterion in the local approach as well as the accepted zone in USA literature. The field of hydropedology accommodates the classification of the various hydrologically active horizons and provides a tool for the handling of horizons with ephemeral wetness. This approach has been variably accepted by mandated authorities in South Africa. The South African soil classification system has evolved through three editions over the past 50 years while retaining the same redox morphology understanding. However, despite the concepts and context of redox morphology having been thoroughly technically adopted by soil scientists, this is not the case within the wetland research and management environment. This especially because the classification system is structured differently from other international systems, and the South African landscape is geologically ancient with mature soils, introducing challenges to resource assessment specialists who rely on international norms and approaches for wetland assessment. This paper reviews the various components of soil classification and redox morphology based on Fe and Mn minerals within the context of the South African soil classification system, the field of hydropedology and wetland delineation indicators. We provide a qualitative correlation between the various diagnostic horizons and materials in the system and their related redox morphology contexts that are relevant to wetland assessment, delineation, and protection in South Africa. This paper therefore aims to serve as a reference point for the description and correlation of various soil hydrological parameters used in formal assessments.

Abstract Creatinine standardisation programmes remain valid. The objective of this work is to describe the experience acquired during the development of a creatinine standardisation programme in a low-resource province and show the aspects that should be considered for its scalability in a similar context. The programme was developed in stages. The first one was carried out in 2010. It consists of a structured survey completed by 49 clinical laboratories (CL) distributed throughout the province. In the second stage (2012) the random error (RE) was adjusted by applying international protocols (CLSI EP-5A). In the third stage (2014-2015), panels of sera were processed with concentrations assigned by a method traceable to the reference and the international standard (CG-IDMS). International protocols were applied to evaluate the total error (TE) of the determination in each laboratory (CLSI EP-10A). In 2016, applying quality tools, the barriers in the process were evaluated. In the RE, it was observed: for a level of 1.00 mg/dL, no CL reached the desirable levels; for a level of 2.5 mg/dL only 9 (23%) CL achieved them. Once the second and third stages were completed, only 18 laboratories (48.7%) managed to adjust the RE and/or TE, but it was difficult to sustain it over time. With respect to materials, reagents, calibrators, and controls, they are produced by the industry depending on the state of their control. The homogeneity of the equipment depends on economic accessibility and volume of work. The environment, temperature, and water quality are a barrier to scalability.

Resumen Los programas de estandarización de creatinina mantienen su vigencia. El objetivo es describir la experiencia adquirida durante el desarrollo de un programa de estandarización de creatinina en una provincia de bajos recursos y mostrar los aspectos que se deben considerar para su escalabilidad en un contexto semejante. El programa se desarrolló en etapas: en la primera (2010) se realizó el relevamiento de 49 laboratorios clínicos (LC) distribuidos en toda la provincia del Chaco, Argentina. En la segunda (2012) se ajustó el error aleatorio (EA) aplicando protocolos internacionales (CLSI EP-5A). En la tercera etapa (2014-2015) se procesaron paneles de sueros con concentraciones asignadas por un método trazable al de referencia y al estándar internacional (CG-IDMS). Se aplicaron protocolos internacionales para evaluar el error total (ET) de la determinación en cada laboratorio (CLSI EP-10A). En 2016, aplicando herramientas de calidad, se evaluaron las barreras en el proceso. Se observó en el EA: para un nivel de 1,00 mg/dL, ningún LC alcanzó los niveles deseables; para un nivel de 2,5 mg/dL solo 9 (23%) los alcanzaron. Concluida la segunda y tercera etapa, solo 18 laboratorios (48,7%) lograron ajustar el EA y/o ET, pero resultó dificultoso sostenerlo en el tiempo. Los reactivos, calibradores y controles son producidos por la industria y depende del estado el control de los mismos. La homogeneidad del equipamiento depende de la accesibilidad económica y del volumen de trabajo. El medio ambiente, la temperatura y la calidad del agua siguen siendo una dificultad para la escalabilidad.

Resumo Os programas de padronização da creatinina permanecem válidos. O objetivo é descrever a experiência adquirida durante o desenvolvimento de um programa de padronização de creatinina em uma província com poucos recursos e mostrar os aspectos que devem ser levados em consideração para sua escalabilidade em um contexto semelhante. O programa foi desenvolvido em etapas: Na primeira (2010), foi realizado um levantamento de 49 laboratórios clínicos (LC) distribuídos em toda a provincia do Chaco, na Argentina. Na segunda etapa (2012) o erro aleatório (EA) foi ajustado através da aplicação de protocolos internacionais (CLSI EP-5A). Na terceira etapa (2014-2015), foram processados paineis de soros com concentrações atribuídas por método rastreável à referência e ao padrão internacional (CG-IDMS). Protocolos internacionais foram aplicados para avaliar o erro total (ET) da determinação em cada laboratório (CLSI EP-10A). Em 2016, aplicando ferramentas de qualidade, foram avaliadas as barreiras no processo. Observou-se na EA: para o nível de 1,00 mg/dL nenhuma LC atingiu os níveis desejáveis; para um nível de 2,5 mg/dL, apenas 9 (23%) os atingiram. Concluídas a segunda e terceira etapas, apenas 18 laboratórios (48,7%) conseguiram ajustar o EA e/ou o ET, mas foi difícil sustentá-lo ao longo do tempo. No que diz respeito aos reagentes, calibradores e controles, eles são produzidos pela indústria. dependendo do estado o seu controle. A homogeneidade do equipamento depende da acessibilidade econômica e do volume de trabalho. O meio ambiente, a temperatura e a qualidade da água continuam sendo uma dificuldade para a escalabilidade.

Abstract In view of the growing scarcity of water for agriculture, the increase in food demand and future drought scenarios posed by climate change, it is essential to design new technologies that contribute to lower water consumption. In this research, high-resolution images have been used to estimate evapotranspiration in rice fields by applying the METRICTM (Mapping Evapotranspiration at High Resolution using Internalized Calibration) energy balance model. For this purpose, 5900 m2 of crop were monitored under continuous flood irrigation (CF) and 2600 m2 under alternate wetting and drying irrigation (AWD), in addition to some plots with lateral filtration. Ten flights were conducted between tillering and flowering phases, five flights with a Matrice 210 UAV equipped with a Parrot Sequoia multispectral camera, and five flights with a Matrice 300 RTK equipped with a H20T thermal camera. Field data were collected from vegetation indices (NDVI and LAI), and readings from a radiometer, to adjust information from multispectral and thermal images, respectively, and to obtain the components of the surface energy balance. Mean values for crop evapotranspiration (ETc) of 6.34 ± 1.49 and 5.84 ± 0.41 mm d-1 were obtained for IC irrigation and AWD irrigation, respectively, obtaining a water saving of 42% with a yield reduction of 14%, providing a guide for proper irrigation management, however, it is suggested to use the model to optimize yield by obtaining critical thresholds for optimal application of AWD in the face of water resource scarcity.

Resumen Ante la creciente escasez del agua para la agricultura, el incremento de la demanda de alimentos y los futuros escenarios de sequía que nos plantea el cambio climático es indispensable diseñar nuevas tecnologías que contribuyan a un menor consumo de agua. En esta investigación se han empleado imágenes de alta resolución para estimar la evapotranspiración en arrozales aplicando el modelo de balance de energía METRICTM (Mapping Evapotranspiration at High Resolution using Internalized Calibration). Para ello, se monitorizaron 5900 m2 de cultivo bajo riego por inundación continua (IC) y 2600 m2 bajo la técnica de riego de alternancia humedecimiento y secado (AWD, por sus siglas en inglés), además de algunas parcelas con filtración lateral. Se realizaron 10 vuelos entre las etapas de macollamiento y floración, cinco vuelos con un VANT Matrice 210 con una cámara multiespectral Parrot Sequoia, y cinco vuelos con un Matrice 300 RTK equipado con una cámara térmica H20T. Se colectó información de campo de los índices de vegetación (NDVI e IAF), y lecturas de un radiómetro, para ajustar información de las imágenes multiespectrales y térmicas, respectivamente; y obtener los componentes del balance de energía en superficie. Se obtuvo valores medios para evapotranspiración del cultivo (ETc) de 6,34 ±1,49 y 5,84 ± 0,41 mm d-1 para riego IC y riego AWD, respectivamente, obteniéndose un ahorro de agua del 42% con una reducción del rendimiento en 14%, proporcionando una guía para la gestión adecuada del riego, sin embargo, se sugiere utilizar el modelo para optimizar el rendimiento obteniendo umbrales críticos para la aplicación óptima de AWD frente a la escasez del recurso hídrico.

Non-perennial rivers (NPRs) have three hydrological states; each state has its importance, function and implication for water resource management. The dynamics of these states have been inadequately assessed and understood. Hence, this study sought to determine the spatiotemporal variations in the hydrological :onditions of NPRs, focusing on the Touws River-Karoo drylands and Molototsi River within the semi-arid region of the Limpopo Province of South Africa. Additionally, the study aimed to delineate and characterize the primary areas contributing to runoff in these two river systems. Sentinel-1 and Sentinel-2 satellite data sources were employed in this study. Specifically, the modified normalized difference water index (MNDWI) derived from Sentinel-2 was utilized to delineate water surface areas along the two rivers. Subsequently, these derived datasets were utilized to assess the hydrological states over a 32-month period (2019-2022,. Based on the presence of water, the river's state was classified as flowing, pooled, or dry. The results showed that remote sensing can be used to determine the hydrological state of the two river systems with -90% overall accuracy. However, there is about a 30% chance that a flow event can be missed using Sentinel-2 due to clouds and temporal resolution. Some of these gaps can be filled using synthetic aperture radar (SAR) data (Sentinel-1), as demonstrated with the Molototsi River. In the Molototsi catchment, the upper catchment contributes the majority of flows. For theTouws River, the southwestern part of the catchment was determined as the major contributing area for the observed flows. This suggests that the chosen observation site might riot be representative of upper catchment dynamics; therefore, a monitoring site in the upper catchment is equired. This study provided hydrological information and an approach that can be used to monitor the hydrological states for better understanding and management of NPRs and catchments.

Abstract The São Francisco River Basin (SFRB) is extremely important for both the local rural and urban population, running through several states and municipalities in Brazil. Thus, the study of the spatial distribution of rainfall in the SFRB, supported by the application of geostatistics, offers valuable insights for water management and planning. In this study, data from 341 rainfall stations were used, corresponding to the period between 1989 and 2018, and monthly accumulated rainfall analyzed. About the trends, positive estimates for latitude, except for April, highlight that the accumulated precipitation decreases from south to north each month. In December, 85.10% of the spatial variability of rainfall was explained by the trend of rainfall concerning geographical coordinates. Concerning spatial dependence, the analyzed data predominantly exhibited the exponential variogram model. The conducted analyses offered a holistic view of rainfall in the region, facilitating the understanding of spatial patterns and shedding light on challenges in the face of climate change. Our research limited on the spatial modeling of rainfall in the SFRB, and future work should include modeling socio-economic and environmental impacts in the region concerning the spatial irregularity of rainfall. SFRB (SFRB population Brazil Thus geostatistics planning 34 used 198 2018 trends latitude April month December 8510 85 10 85.10 coordinates dependence model change socioeconomic socio economic 3 19 201 851 8 1 85.1 20 85. 2

Resumo A Bacia Hidrográfica do Rio São Francisco (SFRB) é de extrema importância tanto para a população rural quanto urbana local, percorrendo diversos estados e municípios do Brasil. O estudo da distribuição espacial das chuvas na SFRB, apoiado na aplicação da geoestatística, oferece insights valiosos para a gestão e planejamento hídrico. Nesse estudo foram utilizados dados de 341 estações pluviométricas, correspondentes ao período entre 1989 e 2018, e analisadas as chuvas acumuladas mensais. Sobre a tendência, estimativas positivas para a latitude, com exceção de abril, ressaltam que a precipitação acumulada em cada mês diminui de sul para norte. No mês de dezembro, 85,10% da variabilidade espacial das chuvas foi explicada pela tendência das chuvas em relação às coordenadas geográficas. Na dependência espacial, os dados analisados mostram predomínio do modelo de variograma exponencial. As análises realizadas proporcionaram uma visão holística das chuvas na região, permitindo a compreensão dos padrões espaciais e lançando luz sobre os desafios apresentados em um cenário de mudanças climáticas. Essa pesquisa limitou-se à modelagem espacial das chuvas na SFRB, e uma modelagem dos impactos socioeconômicos e ambientais na região em relação à irregularidade espacial das chuvas é essencial para trabalhos futuros. SFRB (SFRB local Brasil geoestatística hídrico 34 pluviométricas 198 2018 mensais latitude abril norte dezembro 8510 85 10 85,10 geográficas exponencial climáticas limitouse limitou se futuros 3 19 201 851 8 1 85,1 20 85, 2