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Abstract No-take marine protected areas (MPAs) can mitigate the effects of overfishing, climate change and habitat degradation, which are leading causes of an unprecedented global biodiversity crisis. However, assessing the effectiveness of MPAs, especially in remote oceanic islands, can be logistically challenging and often restricted to relatively shallow and accessible environments. Here, we used a long-term dataset (2010–2019) collected by the DeepSee submersible of the Undersea Hunter Group that operates in Isla del Coco National Park, Costa Rica, to (1) determine the frequency of occurrence of elasmobranch species at two depth intervals (50–100 m; 300–400 m), and (2) investigate temporal trends in the occurrence of common elasmobranch species between 2010 and 2019, as well as potential drivers of the observed changes. Overall, we observed 17 elasmobranch species, 15 of which were recorded on shallow dives (50–100 m) and 11 on deep dives (300–400 m). We found a decreasing trend in the probability of occurrence of Carcharhinus falciformis over time (2010–2019), while other species (e.g. Taeniurops meyeni, Sphyrna lewini, Carcharhinus galapagensis, Triaenodon obesus, and Galeocerdo cuvier) showed an increasing trend. Our study suggests that some species like S. lewini may be shifting their distributions towards deeper waters in response to ocean warming but may also be sensitive to low oxygen levels at greater depths. These findings highlight the need for regional 3D environmental information and long-term deepwater surveys to understand the extent of shark and ray population declines in the ETP and other regions, as most fishery-independent surveys from data-poor countries have been limited to relatively shallow waters.

Durante los años 1853 y 1854 surgió una ola de huelgas en varios distritos industriales de Inglaterra, especialmente en los sectores textiles de Lancashire y Manchester. Este ciclo de luchas, que pugnaba principalmente por un aumento de los salarios, fue visto por Ernest Jones y el movimiento Cartista como una oportunidad para organizar una asociación obrera a escala nacional. Karl Marx, que compartía la visión de los cartistas, analizó el movimiento desde el New York Tribune, brindando apoyo a la iniciativa a la que dio lugar: el Parlamento Obrero. A continuación, se ofrece la traducción de cuatro textos periodísticos que Marx publicó en apoyo a la institución obrera –la mayoría inéditos en español–, seguidos de «Las luchas por la organización obrera en la época victoriana (1853-1854)», un estudio crítico sobre el ciclo de huelgas y las expectativas de organización obrera durante aquellos años, donde se defiende que este fallido intento de organización constituye un precedente de la sección británica de la Asociación Internacional de Trabajadores. La traducción y edición de los textos de Marx, y el estudio crítico que los acompaña, han sido realizados por Mario Espinoza Pino (Universidad de Granada).

Sharks and rays are vital coral reef species. This study shows that nearly two thirds (59%) of the 134 coral-reef associated species are threatened with extinction. The main cause of their decline is found to be overfishing, both targeted and unintentional, and extinction risk is greater for larger species found in nations with higher fishing pressure and weaker governance.

Abstract The Bull Shark (Carcharhinus leucas) faces varying levels of exploitation around the world due to its coastal distribution. Information regarding population connectivity is crucial to evaluate its conservation status and local fishing impacts. In this study, we sampled 922 putative Bull Sharks from 19 locations in the first global assessment of population structure of this cosmopolitan species. Using a recently developed DNA‐capture approach (DArTcap), samples were genotyped for 3400 nuclear markers. Additionally, full mitochondrial genomes of 384 Indo‐Pacific samples were sequenced. Reproductive isolation was found between and across ocean basins (eastern Pacific, western Atlantic, eastern Atlantic, Indo‐West Pacific) with distinct island populations in Japan and Fiji. Bull Sharks appear to maintain gene flow using shallow coastal waters as dispersal corridors, whereas large oceanic distances and historical land‐bridges act as barriers. Females tend to return to the same area for reproduction, making them more susceptible to local threats and an important focus for management actions. Given these behaviors, the exploitation of Bull Sharks from insular populations, such as Japan and Fiji, may instigate local decline that cannot readily be replenished by immigration, which can in turn affect ecosystem dynamics and functions. These data also supported the development of a genetic panel to ascertain the population of origin, which will be useful in monitoring the trade of fisheries products and assessing population‐level impacts of this harvest.

En este artículo nos interrogamos sobre los efectos de Mayo del 68 en la historia de la filosofía. Para abordar esta cuestión elaboramos una reconstrucción del marco filosófico y el campo académico en los compases previos a la revuelta, señalando cómo dentro de los estilos filosóficos existentes se preparaban importantes mutaciones –fundamentalmente en las relaciones entre la filosofía y las ciencias–. A partir de la trayectoria de Pierre Macherey, mostramos las características del espacio filosófico del Mayo del 68 y sus cambios –ampliación de públicos, hibridación de la filosofía con otros saberes, empresas intelectuales colectivas, filiación militante de los discursos –, mostrando cómo se estabilizan nuevos modelos de filosofía ya en el Post 68. En este punto, abordamos la práctica filosófica de Michel Foucault y Louis Althusser, explorando sus innovaciones a la hora de entender la filosofía. Finalmente, trazamos un diálogo entre las concepciones de la filosofía de Althusser y Macherey; en sus tensiones se expresan las posibilidades de un nuevo canon filosófico y una nueva práctica de la filosofía.

Abstract Background Rickettsial diseases are considered important in public health due to their dispersal capacity determined by the particular characteristics of their reservoirs and/or vectors. Among the latter, fleas play an important role, since the vast majority of species parasitize wild and invasive rodents, so their detection is relevant to be able to monitor potential emerging diseases. The aim of this study was to detect, characterize, and compare Rickettsia spp. from the fleas of micromammals in areas with different human population densities in Chile. Methods The presence of Rickettsia spp. was evaluated by standard polymerase chain reaction (PCR) and sequencing in 1315 fleas collected from 1512 micromammals in 29 locations, with different human population densities in Chile. A generalized linear model (GLM) was used to identify the variables that may explain Rickettsia prevalence in fleas. Results DNA of Rickettsia spp. was identified in 13.2% (174 of 1315) of fleas tested. Fifteen flea species were found to be Rickettsia-positive. The prevalence of Rickettsia spp. was higher in winter, semi-arid region and natural areas, and the infection levels in fleas varied between species of flea. The prevalence of Rickettsia among flea species ranged between 0–35.1%. Areas of lower human density showed the highest prevalence of Rickettsia. The phylogenetic tree showed two well-differentiated clades with Rickettsia bellii positioned as basal in one clade. The second clade was subdivided into two subclades of species related to Rickettsia of the spotted fever group. Conclusions To our knowledge, this is the first report of the occurrence and molecular characterization of Rickettsia spp. in 15 flea species of micromammals in Chile. In this study, fleas were detected carrying Rickettsia DNA with zoonotic potential, mainly in villages and natural areas of Chile. Considering that there are differences in the prevalence of Rickettsia in fleas associated with different factors, more investigations are needed to further understand the ecology of Rickettsia in fleas and their implications for human health.

Defining demographically independent units and understanding patterns of gene flow between them is essential for managing and conserving exploited populations. The critically endangered scalloped hammerhead shark, Sphyrna lewini, is a coastal semi-oceanic species found worldwide in tropical and subtropical waters. Pregnant females give birth in shallow coastal estuarine habitats that serve as nursery grounds for neonates and small juveniles, whereas adults move offshore and become highly migratory. We evaluated the population structure and connectivity of S. lewini in coastal areas and one oceanic island (Cocos Island) across the Eastern Tropical Pacific (ETP) using both sequences of the mitochondrial DNA control region (mtCR) and 9 nuclear-encoded microsatellite loci. The mtCR defined two genetically discrete groups: one in the Mexican Pacific and another one in the central-southern Eastern Tropical Pacific (Guatemala, Costa Rica, Panama, and Colombia). Overall, the mtCR data showed low levels of haplotype diversity ranging from 0.000 to 0.608, while nucleotide diversity ranged from 0.000 to 0.0015. More fine-grade population structure was detected using microsatellite loci where Guatemala, Costa Rica, and Panama differed significantly. Relatedness analysis revealed that individuals within nursery areas were more closely related than expected by chance, suggesting that S. lewini may exhibit reproductive philopatric behaviour within the ETP. Findings of at least two different management units, and evidence of philopatric behaviour call for intensive conservation actions for this highly threatened species in the ETP.

Understanding the link between seamounts and large pelagic species (LPS) may provide important insights for the conservation of these species in open water ecosystems. The seamounts along the Cocos Ridge in the Eastern Tropical Pacific (ETP) ocean are thought to be ecologically important aggregation sites for LPS when moving between Cocos Island (Costa Rica) and Galapagos Islands (Ecuador). However, to date, research efforts to quantify the abundance and distribution patterns of LPS beyond the borders of these two oceanic Marine Protected Areas (MPAs) have been limited. This study used drifting-pelagic baited remote underwater video stations (BRUVS) to investigate the distribution and relative abundance of LPS at Cocos Ridge seamounts. Our drifting-pelagic BRUVS recorded a total of 21 species including elasmobranchs, small and large teleosts, dolphins and one sea turtle; of which four species are currently threatened. Depth of seamount summit was the most significant driver for LPS richness and abundance which were significantly higher at shallow seamounts (< 400 m) compared to deeper ones (> 400m). Distance to nearest MPA was also a significant predictor for LPS abundance, which increased at increasing distances from the nearest MPA. Our results suggest that the Cocos Ridge seamounts, specifically Paramount and West Cocos which had the highest LPS richness and abundance, are important aggregation sites for LPS in the ETP. However, further research is still needed to demonstrate a positive association between LPS and Cocos Ridge seamounts. Our findings showed that drifting pelagic BRUVS are an effective tool to survey LPS in fully pelagic ecosystems of the ETP. This study represents the first step towards the standardization of this technique throughout the region.

El objetivo de la presente investigación fue optimizar el proceso de escaldado y método de congelación previos a la liofilización sobre la variación del contenido de vitamina C en una muestra de aguaymanto (Physalis peruviana L.) envasado procedente de la ciudad de Huánuco, provincia de Huánuco. Las variables de entrada consideradas fueron: tipo de escaldado (por inmersión a 75 °C durante 2 minutos y a vapor a 95 °C durante 2 minutos), y, el tipo de congelación (ultrarrápida con nitrógeno líquido, a -196 °C, y lenta, a -25 °C durante 1 día), aplicadas bajo la metodología de Taguchi con 12 ensayos (3 réplicas). Luego del pretratamiento de escaldado y congelación, las muestras se liofilizaron a condiciones de 0,22 mbar y -50 °C durante 24 horas. Esto se hizo con el fin de cuantificar la retención de la vitamina C en las muestras analizadas. Las muestras que fueron escaldadas por vapor y con una congelación ultrarrápida presentaron mayor retención del contenido de vitamina C (73,33 ± 2,07 mg/100 g de materia seca) en comparación con el producto inicial sin ningún tratamiento (175,94 ± 11,31 mg/100 g de materia seca). El análisis de resultados sugiere que la aplicación del escaldado a vapor como pretratamiento a la liofilización es una tecnología que favorece la conservación de vitamina C del Aguaymanto, permitiendo conservar mejor la calidad y características funcionales.

Background Rattus rattus is a widely distributed, invasive species that presents an important role in disease transmission, either directly or through vector arthropods such as fleas. These black rats can transmit a wide variety of pathogens, including bacteria of the genus Bartonella, which can cause diseases in humans and animals. In Chile, no data are available identifying fleas from synanthropic rodents as Bartonella vectors. The aim of this study was to investigate the prevalence of Bartonella spp. in the fleas of R. rattus in areas with different climate conditions and featuring different human population densities. Methods In all, 174 fleas collected from 261 R. rattus captured from 30 localities with different human densities (cities, villages, and wild areas) across five hydrographic zones of Chile (hyper-arid, arid, semi-arid, sub-humid, and hyper-humid) were examined. Bartonella spp. presence was determined through polymerase chain reaction, using gltA and rpoB genes, which were concatenated to perform a similarity analysis with BLAST and phylogenetic analysis. Results Overall, 15 fleas species were identified; Bartonella gltA and rpoB fragments were detected in 21.2% (37/174) and 19.5% (34/174) of fleas, respectively. A total of 10 of the 15 fleas species found were positive for Bartonella DNA. Leptopsylla segnis was the most commonly collected flea species (n = 55), and it also presented a high prevalence of Bartonella DNA (P% = 34.5%). The highest numbers of fleas of this species were collected in villages of the arid zone. There were no seasonal differences in the prevalence of Bartonella DNA. The presence of Bartonella DNA in fleas was recorded in all hydrographic areas, and the arid zone presented the highest prevalence of this species. Regarding areas with different human densities, the highest prevalence was noted in the villages (34.8% gltA and 31.8% rpoB), followed by cities (14.8% gltA and 11.1% rpoB) and wild areas (7.4% gltA and 14.8% rpoB). The BLAST analysis showed a high similitude (>96%) with four uncharacterized Bartonella genotypes and with two species with zoonotic potential: B. mastomydis and B. tribocorum. The phylogenetic analysis showed a close relationship with B. elizabethae and B. tribocorum. This is the first study to provide evidence of the presence of Bartonella in fleas of R. rattus in Chile, indicating that the villages and arid zone correspond to areas with higher infection risk.

Sawnwood of teak (Tectona grandis L. f.) from a Costa Rica plantation was thermally treated at different process conditions using thermo-vacuum technology. The main objectives of the study were to find the optimal combination of the process parameters, i.e. temperature (T), and duration (t), in order to minimise the colorimetric difference between sapwood and heartwood, and to evaluate the influence of the treatment on the modification pattern of physical properties of the material. The resulting mass loss (ML), hygroscopicity (H), dimensional stability (ASE), and lightness (L) were measured and compared. As expected, the temperature (T) is the main parameter influencing the extent of modification. The measured ML values turned out to be moderate even at high T values if compared with other hardwoods. The temperature range between 180 °C and 190 °C minimizes the colorimetric difference between treated sapwood and not treated heartwood.

The occurrence of sharks on coral reefs has been well documented for decades, especially since the advent of SCUBA diving. Despite this, it is only within the last decade that substantial research effort has been directed at these species. Research effort has increased in conjunction with the realization that reef shark populations have experienced significant declines throughout their distribution. However, trends in declines have been coupled with reports of high abundance in some areas providing confusion about what healthy reef shark populations should look like. Given that coral reefs are among the most biologically diverse and productive habitats, but also are one of the most threatened by climate change due to the effects of rising temperature and declining pH, there is a need to understand reef sharks to better predict consequences for their populations. Studies of reef sharks also have the potential to provide insights into the functioning of their populations and ecosystems more broadly because of the spatially constrained nature of their distributions, and high water visibility in most locations. These aspects make studying reef shark populations integral to understanding coral reef ecosystem dynamics and resilience to pressures. This paper synthesizes a number of key questions about coral reef sharks based on our experience researching this group of species over the past decade. Key research gaps and critical questions include aspects of life history, population dynamics, ecology, behavior, physiology, energetics, and more. This synthesis also considers the methods used to date, and what new and emerging techniques may be available to improve our understanding of reef shark populations. The synthesis will highlight how even basic questions relating to reef shark population sizes, how large they should be, and what impacts do they have on reef ecosystems, remain either unanswered or highly controversial.

Understanding key aspects of the biology and ecology of chondrichthyan fishes (sharks, rays, and chimeras), as well as the range of threats affecting their populations is crucial given the rapid rate at which some species are declining. In the Eastern Tropical Pacific (ETP), the lack of knowledge, unreliable (or non-existent) landing statistics, and limited enforcement of existing fisheries regulations has hindered management and conservation efforts for chondrichthyan species. This review evaluated our current understanding of Costa Rican chondrichthyans and their conservation status. Specifically, we (1) provide an updated checklist on the species richness, habitat use, and distribution patterns, (2) summarize the most relevant chondrichthyan studies (scientific publications, theses, and official technical reports), (3) identify knowledge gaps, (4) discuss fisheries-related threats, and (5) highlight the management challenges and research needs to effectively protect their populations. A total of 99 chondrichthyan species are formally recorded in Costa Rican waters, from which 15% are threatened with extinction and 41% are “Data Deficient” based on the IUCN (International Union for Conservation of Nature) Red List. A total of 121 studies were published between 1891 and 2017; 82% in the Pacific (24% from Isla del Coco) and only 18% from the Caribbean Sea. These results highlight the need to redirect research efforts on specific taxonomic groups and geographic regions (i.e., Caribbean). Based on our review, improving the quality and quantity of fisheries landing statistics, as well as determining the degree of overlap between chondrichthyans and Costa Rican fisheries remains a priority. We proposed an adaptive management framework for chondrichthyan fisheries in data-poor countries where management goals/targets are clearly defined. This framework could strengthen the conservation of chondrichthyan populations in Costa Rica and the region.

El objetivo de esta investigación fue evaluar el efecto de la osmodeshidratación como pretratamiento a la liofilización sobre el contenido de antocianinas en el arándano (Vaccinium corymbosum L.) y su capacidad de rehidratación. Se utilizó el diseño compuesto central rotacional (DCCR) con concentraciones de sacarosa de 40 a 60 °Brix y temperaturas de 30 a 50°C de la solución osmótica, totalizando 11 ensayos, los que tuvieron una duración de 4 horas. Los arándanos osmodeshidratados se congelaron con nitrógeno líquido (-196 °C) a presión atmosférica y se liofilizaron a condiciones de 0,22 mbar y -50 °C durante 24 horas; cuantificándose el contenido de antocianinas (mg cianidina-3-glucosido/L) y la capacidad de rehidratación (CR) en el arándano liofilizado. Los arándanos sometidos a una solución osmótica de 50 °Brix y 50 °C presentaron el mayor contenido de antocianinas 126,64 (mg cianidina-3-glucosido/L) en tanto con solución osmótica de 57 °Brix y 47 °C, se obtuvo el mayor porcentaje de rehidratación 69,15%, que es superior al 25,27% encontrado para el arándano fresco liofilizado. Los resultados sugieren que la aplicación de la deshidratación osmótica como pretratamiento a la liofilización es una tecnología que no favorece la retención de las antocianinas del arándano (Vaccinium corymbosum L.), debido a que ocasiona un alto porcentaje de pérdida de estos compuestos por lixiviación, sin embargo, representa una opción para obtener productos con una mayor capacidad de rehidratación luego de ser liofilizados.

El contenido de metabolitos tales como fenoles y flavonoides en el membrillo se ha relacionado con efectos de promoción de la salud humana debido a sus propiedades antioxidantes y funcionales. Este estudio tuvo como objetivo investigar el impacto térmico del secado por ventana refractanteTM (VR) combinado con variables de temperatura y tiempo sobre el contenido de fenoles y flavonoides totales en cáscaras de membrillo (Cydonia oblonga L. variedad “Serrano”). El diseño experimental comprendió una metodología de superficie de respuesta utilizando un Diseño Compuesto Central Rotable (DCCR). Los rangos variables empleados fueron de 75-95 ºC (temperatura) y 20-60 min (tiempo), así mismo se utilizó una lámina Mylar (polietileno de tereftalato metalizado) como película refractante de 0,1 mm. Cromatografía Líquida de Alta Resolución (HPLC) fue utilizada para determinar el contenido de flavonoides totales en los ensayos. Los resultados mostraron una reducción de aproximadamente 13% en el contenido de fenoles totales en los tratamientos aplicados (T° = 74-78 °C, t = 15-25 min) con respecto al contenido de las muestras frescas. Para el caso de los flavonoides totales, los análisis revelaron que cuando se trabaja con temperaturas entre 74-78 °C y tiempos cortos de 15-25 minutos, producen un aumento (3 veces más) en el contenido de estos metabolitos. El estudio concluye que el secado por VR puede producir una menor reducción en el contenido de fenoles totales y un aumento significativo en el contenido de flavonoides totales en menores tiempos comparados con otros métodos de secado existentes

Nuestras ciudades generan cada vez más cantidad de residuos cuya disposición final se realiza en botaderos a cielo abierto constituyendo un problema para la salud pública, además los elevados volúmenes suponen importantes costos de recolección. Pese a esto, los residuos orgánicos también son una fuente importante de compuestos bioactivos que pueden ser reutilizados debido a sus propiedades favorables, pudiendo tener un efecto benéfico para la salud humana. El presente estudio tuvo como objetivo evaluar la técnica del secado por aire convectivo (AC) combinado con variables de temperatura y tiempo sobre el contenido de fenoles y flavonoides totales para el aprovechamiento de los residuos agroindustriales del membrillo (Cydonia oblonga L. variedad “Serrano”). Fue utilizado un Diseño Compuesto Central Rotable (DCCR) con temperatura entre 50 y 70 °C y tiempo entre 150 y 240 minutos. Se utilizó Cromatografía Líquida de Alta Resolución (HPLC) para determinar el contenido de flavonoides totales en los ensayos. Se determinó que el secado por AC produjo una reducción del 35% aproximadamente en contenido de fenoles totales cuando se trabaja con temperaturas de 48 a 58 °C y tiempo de 140 a 220 minutos, con respecto a las muestras frescas. Mientras que, para el contenido de flavonoides totales, los análisis revelaron que las cáscaras de membrillo secadas con tratamientos que combinan temperaturas entre 54 y 64 °C y tiempo entre 160 y 220 minutos, producen un aumento considerable de hasta 5 veces más respecto a la muestra original. La técnica de secado por aire convectivo (AC) puede ser utilizada para darle valor agregado a la recuperación de compuestos bioactivos de residuos agroindustriales tales como las cáscaras del membrillo. La explotación de estos productos podría incrementar el valor de la agroindustria en países tropicales y favorecer el cuidado del medio ambiente.

El presente trabajo de investigación tuvo como objetivo evaluar los residuos principales provenientes de la industria azucarera y lechera, como son la melaza de caña y suero lácteo como sustrato para la producción de Saccharomyces cerevisiae, teniendo como medio de cultivo control, jugo de uva suplementado. La Saccharomyces fue cultivada en balones de vidrio de 2000 mL de capacidad con sistema acoplado de aireado continuo para cada uno de los sustratos. La biomasa obtenida durante cada hora de crecimiento se cuantificó por medio de la técnica de la cámara de Neubauer y se evaluaron los parámetros de pH y °Brix en los medios de cultivo a través del tiempo. Adicionalmente se evaluaron los modelos matemáticos de Gompertz corregido y Logístico en la cinética de crecimiento de la levadura; permitiendo obtener una velocidad específica de crecimiento (μmáx) [h-1] de 0.0923 y 0.1103; precedida de un tiempo de latencia (λ) de 1.5044 y 2.8230 h y un tiempo de generación (G) [h] de 3.2608 y 2.7292 para Gompertz. Una velocidad específica de crecimiento (μmáx) [h-1] de 0.0869 y 0.1033; precedida de un tiempo de latencia (λ) de 1.5596 y 2.8583 h y un tiempo de generación (G) [h] de 3.4631 y 2.9134 para el modelo Logístico; tanto para el medio melaza + suero lácteo como para el jugo de uva suplementado respectivamente. En ambos casos se obtuvo un buen ajuste entre los datos experimentales y los valores predichos por los modelos. El coeficiente de determinación R2 para los dos modelos es superior al 90% (0.9896 y 0.9812 – Gompertz/ 0.9774 y 0.9709 – Logístico) (Melaza + Suero/ Jugo de uva suplementado); lo que demuestra que ambos modelos explican un alto porcentaje de la variabilidad de los datos. Resulta ventajoso el modelamiento a través del modelo corregido de Gompertz, porque permite obtener los parámetros de la cinética de crecimiento de manera directa.

The consumption of vegetables with the greatest nutraceutical potential, especially those with high levels of antioxidants such as anthocyanin and phenolic compounds, has become popular among health conscious consumers. The aim of this research was to determine the nutraceutical potential of sirimbache fruits (Gaultheria glomerata (Cav.) Sleumer). Characterization of the berries resulted in the following: 11.4 °Brix, 3.25 pH, 0.35% acidity, 83.74% moisture, 0.16% ash, monomeric anthocyanins (112.88 mg cyanidin 3-glucoside / 100 g of sample), total phenolic compounds (344.37 mg of gallic acid / 100 g of sample) and vitamin C (13.87 mg ascorbic acid/ 100 g of sample). These values indicate that sirimbache is a nutraceutical food of great interest. Therefore, the expansion of sirimbache to health conscious markets may be feasible. Such expansion is of great importance for rural agribusiness, as it could promote the development of new agroindustrial projects in the province of Celendin and other Andean areas of Peru.

El objetivo de este artículo es criticar la representación tradicional del trabajo periodístico de Karl Marx, habitualmente olvidado por un canon engañoso que sólo asume sus artículos al precio de convertirlos en una obra menor. Uno de los problemas de esta concepción tradicional es que disocia sus contribuciones teóricas y económicas del desarrollo histórico del pensamiento del autor (y también de sus raíces materiales). Intentaremos señalar la importancia del periodismo maduro de Karl Marx en dos áreas: en la construcción de los conceptos centrales de su crítica contra el capitalismo (plusvalor, un enfoque histórico multilineal, una descripción global del mercado mundial, etc.) y en la producción de cartografías políticas para intervenir en el conflicto de clases. Este artículo plantea varias hipótesis y afirmaciones tentativas sobre el periodismo de Karl Marx que pueden servir como punto de partida de una investigación crítica.

El presente trabajo de investigación tuvo como objetivo evaluar el efecto de la concentración de sacarosa y albedo sobre las propiedades fisicoquímicas, reológicas y aceptación general de un cremogenado de granadilla (Passiflora ligularis), y determinar los valores óptimos del edulcorante y gelificante trabajado, en donde el cremogenado presenta la mayor estabilidad y aceptabilidad general. Para cumplir con dicho objetivo, se empleó el diseño compuesto central rotacional (DCCR), realizándose 11 ensayos experimentales para evaluar las variables concentración de sacarosa en el rango de 0-15% y concentración de albedo en el rango de 15-25%. Las pruebas de aceptación general se realizaron con un panel no entrenado de 40 consumidores quienes degustaron un trago denominado “cremogenado de granadilla sour”, manifestando su aceptabilidad por medio de una escala hedónica de 9 puntos. Se determinó que la concentración de sacarosa si tiene efecto sobre la viscosidad, pH, °Brix, acidez titulable y aceptación general, mientras que la concentración de albedo no tiene efecto en ninguno de las variables estudiadas así como también que los valores de concentración de sacarosa y albedo más adecuadas para obtener un cremogenado de granadilla de mayor aceptación general son de 12.82 % y 23.85% respectivamente. Finalmente, se realizó una caracterización fisicoquímica del producto con mayor aceptabilidad general (óptimo), para comprobar su calidad nutricional y vida útil.

Our knowledge of deepwater ecosystems along the Pacific of Central America is extremely limited. We analyzed the diet composition of 200 adult specimens of Lophiodes spilurus ranging in size from 7.8 to 17.8 cm total length (TL). Samples were obtained from deep bottom trawls (depth: 105-238 m) along the central Pacific of Costa Rica. We calculated the percentage of number (% N), weight (% W), and occurrence (% O) of each food item encountered in the stomachs; based on this information, the Index of Relative Importance (IR) was calculated. Moreover, we estimated diet overlap for three different size classes (15.1 cm TL). The results revealed exclusively two groups of benthic prey items: crustaceans (30%) and teleost fish (70%) in their diet. The most frequent preys were pandalid shrimps Plesionika trispinus (% O = 17) and the fathom mora Physiculus rastrelliger (% O = 12). The greatest diversity and frequency of abundance of food items was observed in intermediate-sized individuals (10.1-15.0 cm TL). Small-sized L. spilurus (< 10.1 cm TL) fed mainly on teleost fish, while larger (> 15.0 cm TL) preyed on large-sized stomatopods and teleost fish. There was a clear diet overlap between small and intermediate-sized L. spilurus (p < 0.05). However, differences in diet-overlap were not detected in small and large-sized individuals or intermediate and large-sized specimens (p > 0.05). Our results suggest that L. spilurus feeds exclusively on crustaceans (Decapoda and Stomatopoda) and benthic teleost fish along the Pacific of Costa Rica. While small and large-sized individuals showed a more pronounced selectivity for certain prey items, the high diversity of benthic prey items observed in intermediate-sized specimens suggest a more opportunistic foraging behavior. Rev. Biol. Trop. 56 (4): 1959-1970. Epub 2008 December 12.Nuestro conocimiento de los ecosistemas marinos de profundidad a lo largo de la costa centroamericana es muy limitado. En el presente estudio se analizó la composición alimenticia de 200 especimenes adultos de Lophiodes spilurus que medían entre 7.8 y 17.8 cm longitud total (LT). Las muestras fueron obtenidas de arrastres camaroneros (profundidad: 105-238 m) a lo largo del Pacífico Central de Costa Rica. Calculamos el porcentaje del número (% N), peso (% W) y presencia (% O) de cada ítem alimenticio encontrado en los estómagos. Basados en esta información, calculamos el Índice de Importancia Relativa (IR). Además, estimamos el traslape en la dieta de tres diferentes clases de tamaño (15.0 cm LT). Los resultados revelaron, exclusivamente, dos grupos de presas bentónicas: crustáceos (30%) y peces teleósteos (70%). Las presas más frecuentes fueron el camarón pandalido Plesionika trispinus (% O = 17) y la mora Physiculus rastrelliger (% 0 = 12). La mayor diversidad y frecuencia de abundancia de ítems alimenticios se observó en individuos intermedios (10.1-15.0 cm LT). Individuos pequeños (< 10.1 cm TL) se alimentaron principalmente de peces teleósteos, mientras que individuos de mayor tamaño (> 15.0 cm TL) consumieron organismos de mayor tamaño y peso como estomatópodos y peces teleósteos. Se encontró un claro traslape en la composición alimenticia de individuos de tamaño pequeño e intermedio de L. spilurus (p < 0.05). Sin embargo, estas diferencias no se detectaron en individuos de tamaño pequeño y grande, ni en individuos intermedios y grandes (p > 0.05). Nuestros resultados sugieren que en el Pacífico de Costa Rica L. spilurus se alimenta exclusivamente de crustáceos (Decapoda and Stomatopoda) y peces teleósteos bentónicos. Los especimenes medianos parecen alimentarse de forma oportunista.

El impacto de las minerías de oro ha generado una gran preocupación por el deterioro de los hábitats acuáticos y la fragmentación de los sistemas naturales. Las perturbaciones antropogénicas sobre la estructura y heterogeneidad del sistema pueden influir en la estabilidad de las comunidades acuáticas. Sondeos ecológicos rápidos (1996, 2002, 2007) fueron empleados para determinar la estructura, composición y distribución de las comunidades de peces tropicales en varios ríos y quebradas del área de una minería de oro en el Cerro Crucitas, Costa Rica. Además, la composición de especies y abundancia relativa se relacionó con la estructura del hábitat. Se registró un total de 35 especies, de las cuales la sardina Astyanax aeneus (Characidae) y la olomina Alfaro cultratus (Poeciliidae) fueron las especies más abundantes (71%). La mayor riqueza de especies se observó en el Caño Crucitas (s = 19) y la quebrada Minas (s = 18). Se encontró una gran variación en la estructura y composición de las comunidades de peces, principalmente, en el río Infiernillo y Minas (λ = 0.0, F132, 66 = 2.24, p < 0.001). La presencia o ausencia de algunas especies como Gobiomorus dormitor, Rhamdia nicaraguensis, Parachromis loiseillei y Atractosteus tropicus explicaron la mayor parte de la variación espacial entre sitios. La heterogeneidad estructural del hábitat también contribuyó a explicar diferencias importantes entre sitios (λ = 0.004, F60, 183 = 5.52, p < 0.001). El tipo de sustrato (blando y duro) y la estructura del hábitat (elevación, ancho y profundidad) explicaron la mayor parte de la variabilidad observada en el río Infiernillo, el Caño Crucitas y la quebrada Tamagá. Además se encontró una asociación significativa entre las especies y la estructura del hábitat. Este estudio evidencia la complejidad en la estructura y composición de especies que habitan el área de la minería de oro, y acentúa la importancia de la heterogeneidad estructural del hábitat en la dinámica de las comunidades de peces tropicales. El deterioro y fragmentación de los hábitats acuáticos en el área de una minería de oro pueden tener un fuerte efecto negativo sobre la estructura de las comunidades de peces tropicales.Rapid ecological assessment of tropical fish communities in a gold mine area of Costa Rica. Gold mining impacts have generated a great concern regarding aquatic systems and habitat fragmentation. Anthropogenic disturbances on the structure and heterogeneity of a system can have an important effect on aquatic community stability. Ecological rapid assessments (1996, 2002, and 2007) were employed to determine the structure, composition and distribution of tropical fish communities in several rivers and smaller creeks from a gold mining area in Cerro Crucitas, Costa Rica. In addition, species composition and relative abundance were related with habitat structure. A total of 35 species were registered, among which sardine Astyanax aeneus (Characidae) and livebearer Alfaro cultratus (Poeciliidae) were the most abundant fish (71%). The highest species richness was observed in Caño Crucitas (s = 19) and Minas Creek (s = 18). Significant differences in fish communities structure and composition from Infiernillo river and Minas creek were observed (λ = 0.0,F132, 66 = 2.24, p < 0.001). Presence and/or absence of certain species such as Dormitor gobiomorus, Rhamdia nicaraguensis, Parachromis loiseillei and Atractosteus tropicus explained most of the spatial variation among sites. Habitat structure also contributed to explain differences among sites (λ = 0.004, F60, 183 = 5.52, p < 0.001). Substratum (soft and hard bottom types) and habitat attributes (elevation, width and depth) explained most of the variability observed in Infiernillo River, Caño Crucitas and Tamagá Creek. In addition, a significant association between fish species and habitat structure was observed. This study reveals a high complexity in tropical fish communities that inhabit a gold mine area. Furthermore,it highlights the importance of habitat heterogeneity in fish community dynamics. The loss and degradation of aquatic systems in Cerro Crucitas can have a strong negative effect on fish community structure and composition of local species. A better understanding of the use of specific habitats that serve as essential fish habitats can improve tropical fish conservation and management strategies, thus increasing local diversity, and thereby, the biological importance of the area. Rev. Biol. Trop. 56 (4): 1971-1990. Epub 2008 December 12.

Understanding animal movement decisions that involve migration is critical for evaluating population connectivity, and thus persistence. Recent work on sharks has shown that often only a portion of the adult population will undertake migrations, while the rest may be resident in an area for long periods. Defining the extent to which adult sharks use specific habitats and their migratory behaviour is essential for assessing their risk of exposure to threats such as fishing and habitat degradation. The present study used acoustic telemetry to examine residency patterns and migratory behaviour of adult bull sharks (Carcharhinus leucas) along the East coast of Australia. Fifty-six VR2W acoustic receivers were used to monitor the movements of 33 bull sharks in the central Great Barrier Reef (GBR). Both males and females were detected year-round, but their abundance and residency peaked between September and December across years (2012-2014). High individual variability in reef use patterns was apparent, with some individuals leaving the array for long periods, whereas others (36%) exhibited medium (0.20-0.40) or high residency (> 0.50). A large portion of the population (51%) undertook migrations of up to 1,400 km to other coral reefs and/or inshore coastal habitats in Queensland and New South Wales. Most of these individuals (76%) were mature females, and the timing of migrations coincided with the austral summer (Dec-Feb). All migrating individuals (except one) returned to the central GBR, highlighting its importance as a potential foraging ground. Our findings suggest that adult bull sharks appear to be highly dependent on coral reef resources and provide evidence of partial migration, where only a portion of the female population undertook seasonal migrations potentially to give birth. Given that estuarine habitats face constant anthropogenic pressures, understanding partial migration and habitat connectivity of large coastal predators should be a priority for their management.

Los arrecifes son sistemas muy complejos, cuya heterogeneidad mantiene una gran diversidad de organismos. La estructura de las comunidades de peces que forman parte del arrecife varía dentro y entre arrecifes, y se esperaría que la heterogeneidad y estructura del arrecife vaya a influir en la estructura de las comunidades de peces que habitan. Se estudiaron cuatro arrecifes en las Islas Catalinas (Sur, La Pared, Roca Sucia y Sombrero) y uno en la Playa de Ocotal, Pacífico Norte de Costa Rica. Se encontraron diferencias claras en la estructura y composición de las comunidades de peces de arrecife en las Islas Catalinas y Playa Ocotal, y la estructura y composición del hábitat explicaron la mayor parte de la varianza. Ciertos atributos del arrecife como la presencia del alga Caulerpa sertularoides en Ocotal, así como los corales Tubastrea coccinea y Pocillopora spp., en las Islas Catalinas explicaron la variabilidad que existía entre los sitios y como afectaba a la estructura de la comunidad de peces de arrecife. La mariposa Johnrandalia nigrirostris, la damisela Microspathodon dorsalis y el cirujano Prionurus punctatus se correlacionaron directamente con el coral ahermatípico Tubastrea coccinea, en el arrecife de Roca Sucia, mientras que Holocanthus passer se asocio a arrecifes con un mayor porcentaje de sustrato rocoso. Otras especies como Abudefduf troschelli y Halichoeres dispilus se encontraban en mayor cantidad en el arrecife de Ocotal, en donde dominaba el alga Caulerpa sertularioides. Por último, el número y abundancia de peces de arrecife se correlacionó directamente con el índice de rugosidad del sustrato en los arrecifes de Roca Sucia y Ocotal, pero no así los de la Pared y Sombrero.Structure of reef fish communities in Catalinas Islands and Ocotal beach, North Pacific of Costa Rica. The reefs are heterogeneous systems that maintain a high diversity of organisms. Fish community structure varies within and among reefs, so it would be expected that reef structure and heterogeneity should affect fish communities inhabiting reefs. Four reef patches at Catalinas Islands (Sur, La Pared, Roca Sucia and Sombrero) and one in Ocotal beach (10°28’45" N; 85°52’35" W) were studied with visual censuses (July-December 2003). The structure and composition of fishes between Catalinas Islands and Ocotal beach were different, and habitat structure and composition explain most of the variance founded. The presence of the fleshy algae Caulerpa sertularioides in Ocotal, and the corals Tubastrea coccinea and Pocillopora spp. at Catalinas Island explained the variability among sites and how it affected fish community structure and composition. The butterfly fish Johnrandallia nigrirostris, damselfish Microspathodon dorsalis, and surgeon fish Prionurus punctatus were directly correlated with the ahermatipic coral Tubastrea coccinea in Roca Sucia reef, while the angel fish Holacanthus passer was associated to reefs with a major percentage of rocky substrate. Other species such as the damselfish Abudefduf troschelli and Halichoeres dispilus were more abundant at Ocotal, where the algae C. sertularioides dominated. The number and abundance of reef fishes was directly correlated with the rugosity index at the reefs of Roca Sucia and Ocotal, but not at reefs of La Pared and Sombrero. Rev. Biol. Trop. 53(3-4): 523-536. Epub 2005 Oct 3.

Quantifying shark distribution patterns and species-specific habitat associations in response to geographic and environmental drivers is critical to assessing risk of exposure to fishing, habitat degradation, and the effects of climate change. The present study examined shark distribution patterns, species-habitat associations, and marine reserve use with baited remote underwater video stations (BRUVS) along the entire Great Barrier Reef Marine Park (GBRMP) over a ten year period. Overall, 21 species of sharks from five families and two orders were recorded. Grey reef Carcharhinus amblyrhynchos, silvertip C. albimarginatus, tiger Galeocerdo cuvier, and sliteye Loxodon macrorhinus sharks were the most abundant species (>64% of shark abundances). Multivariate regression trees showed that hard coral cover produced the primary split separating shark assemblages. Four indicator species had consistently higher abundances and contributed to explaining most of the differences in shark assemblages: C. amblyrhynchos, C. albimarginatus, G. cuvier, and whitetip reef Triaenodon obesus sharks. Relative distance along the GBRMP had the greatest influence on shark occurrence and species richness, which increased at both ends of the sampling range (southern and northern sites) relative to intermediate latitudes. Hard coral cover and distance across the shelf were also important predictors of shark distribution. The relative abundance of sharks was significantly higher in non-fished sites, highlighting the conservation value and benefits of the GBRMP zoning. However, our results also showed that hard coral cover had a large effect on the abundance of reef-associated shark species, indicating that coral reef health may be important for the success of marine protected areas. Therefore, understanding shark distribution patterns, species-habitat associations, and the drivers responsible for those patterns is essential for developing sound management and conservation approaches.