Detección de secuencias de metalotioneina en la especie invasora Hemidactylus brookii (Squamata: gekkonidae) en Cali

Los metales pesados son una problemática ambiental que va en aumento, y que afecta muchas poblaciones naturales. Este incremento se debe principalmente a actividades antropogénicas. Por lo tanto, es importante definir organismos bioindicadores y mecanismos que den información sobre la salud ambiental con relación a estos contaminantes. En este estudio se pretendió detectar secuencias de la proteína metalotioneina, las cual presenta capacidad de quelar metales y además se expresa en presencia de éstos, usando como modelo de estudio el gecko Hemidactylus brookii en la ciudad de Cali.PregradoBIOLOGO(A

A model for the settling velocity of flocs; application to an aquaculture recirculation tank

Se generalizó un modelo para velocidad de caida de flocs para diferentes tipos de agregados ; de plantas de tratamiento, estuarios y acuacultura.A general model for fl ocs settling velocity is still an open fi eld of research in the scientific literature. In this work, a reduced model of an aquaculture recirculation tank was used to validate a model for floc settling velocity. Cohesive sediments from non-used food and fi sh excreta are a main concern in those tanks design. Excess concentrations of sediments can cause fi sh death or additional costs of energy for aeration. This research is aimed to understand the settling behavior of fl ocs when subjected to a liquid shear rate. A reduced scale model of an aquaculture recirculation tank was build in Plexiglas in order to use particle image velocimetry and particle tracking velocimetry techniques to measure fl uid velocities, solid settling velocities, flocs shape and size. Different fl ow rates and solid concentrations were used to develop varied confi gurations in the system; models for floc settling velocity based on fractal theory were calibrated. Cohesive sediments from fi sh food were observed in long-term experiments at constant fl uid shear rate in the recirculation tank. A group of 50 images were obtained for every 5 min. Image analysis provided us with fl oc settling velocity data and fl oc size. Using fl oc settling velocity data, fl oc density was obtained for different diameters at equilibrium conditions, after 1 h or larger experiments. Statistical analysis of fl oc velocities for different floc sizes allowed us to obtain an expression for the drag coefficient as a function of floc particle Reynolds number (Rep). The results were compared with floc settling velocity results from different researchers. The model is able to define the general behavior of fl oc settling velocity, which shows a reduction for larger fl ocs that is not taken into account in classical models. Only two parameters of the drag coefficient model for a permeable spherical particle are needed to be calibrated, for different types of sediments, in order to have more general applicability.UAE

Determinants of Childhood Zoonotic Enteric Infections in a Semirural Community of Quito, Ecuador.

Domestic animals in the household environment have the potential to affect a child's carriage of zoonotic enteric pathogens and risk of diarrhea. This study examines the risk factors associated with pediatric diarrhea and carriage of zoonotic enteric pathogens among children living in communities where smallholder livestock production is prevalent. We conducted an observational study of children younger than 5 years that included the analysis of child (n = 306) and animal (n = 480) fecal samples for Campylobacter spp., atypical enteropathogenic Escherichia coli, Shiga toxin-producing E. coli, Salmonella spp., Yersinia spp., Cryptosporidium parvum, and Giardia lamblia. Among these seven pathogens, Giardia was the most commonly identified pathogen among children and animals in the same household, most of which was found in child-dog pairs. Campylobacter spp. was also relatively common within households, particularly among child-chicken and child-guinea pig pairs. We used multivariable Poisson regression models to assess risk factors associated with a child being positive for at least one zoonotic enteric pathogen or having diarrhea during the last week. Children who interacted with domestic animals-a behavior reported by nearly three-quarters of households owning animals-were at an increased risk of colonization with at least one zoonotic enteric pathogen (prevalence ratio [PR] = 1.56, 95% CI: 1.00-2.42). The risk of diarrhea in the last seven days was elevated but not statistically significant (PR = 2.27, CI: 0.91, 5.67). Interventions that aim to reduce pediatric exposures to enteric pathogens will likely need to be incorporated with approaches that remove animal fecal contamination from the domestic environment and encourage behavior change aimed at reducing children's contact with animal feces through diverse exposure pathways

Calibration and validation of an aerodynamic method to estimate the spatial variability of sensible and latent heat fluxes over a drip irrigated Merlot vineyard

A study was carried out to calibrate and validate the aerodynamic temperature method for estimating the spatial variability of the sensible (H) and latent (LE) heat fluxes over a drip-irrigated merlot vineyard located in the Maule Region, in Chile. For this study, measurement of energy balance components and meteorological data were collected from the 2006 to 2010 growing seasons. The experimental plot was composed of a 4.25 ha of ‘Merlot’ vineyard, which was equipped with an Eddy- Covariance system and an automatic weather station. The k-fold cross-validation method was utilized to tune and validate a vineyard surface aerodynamic temperature (Taero) model, considering all of the days when Landsat scenes and ground measurements of meteorological data and surface energy balance (SEB) were available. Then, the satellite-based estimations of Taero were utilized to calculate the surface aerodynamic resistance (rah) and, subsequently, heat fluxes of H and LE. Results indicated that the estimated H and rah values were not significantly different to those measured in the vineyard (95% significance level) showing a root mean square (RMSE) and mean absolute error (MAE) between 34–29 W m−2 and 1.01–0.78 s m−1, respectively. Satellite-based computations of LE were somewhat higher than those measured at the time of satellite overpass (RMSE = 63 W m−2; MAE = 56 W m−2), presumably due to the biases embedded in the net radiation (Rn) and soil heat flux (G) computations. The proposed SEB method based on Taero is very simple to implement, presenting similar accuracies on ET mapping to those computed by complex satellitebased models.Sociedad Argentina de Informática e Investigación Operativ

Transient Radio Lines from Axion Miniclusters and Axion Stars

Gravitationally bound clumps of dark matter axions in the form of 'miniclusters' or even denser 'axion stars' can generate strong radio signals through axion-photon conversion when encountering highly magnetised neutron star magnetospheres. We systematically study encounters of axion clumps with neutron stars and characterise the axion infall, conversion and the subsequent propagation of the photons. We show that the high density and low escape velocity of the axion clumps lead to strong, narrow, and temporally characteristic transient radio lines with an expected duration varying from seconds to months. Our work comprises the first end-to-end modeling pipeline capable of characterizing the radio signal generated during these transient encounters, quantifying the typical brightness, anisotropy, spectral width, and temporal evolution of the radio flux. The methods developed here may prove essential in developing dedicated radio searches for transient radio lines arising from miniclusters and axion stars.Comment: v2: Minor updates made to match published version. v1: 17 pages, 15 figure

Análisis sobre la factibilidad de aplicación de ecoeficiencia en la reutilización y reciclaje de paneles solares fotovoltaicos

La industria de la energía en El Salvador en el contexto de la descarbonización de la matriz energética debido al actual cambio climático que experimenta el planeta, ha incrementado la generación a partir de las energías renovables, contando con la energía solar fotovoltaica como alternativa, pese a que el uso de las energías renovables tiene como finalidad disminuir la contaminación y disminuir la emisión de gases, estas no son libres de la generación de residuos, convirtiéndose esto en una problemática de residuos de aparatos eléctricos y electrónicos que a largo plazo se afrontará en el país pero en a corto plazo se afrontará en el mundo, países como Chile y España están investigando lo métodos más eficientes de reciclaje en cuanto a este tipo de desechos que se generan.Los paneles solares tienen vida útil muy amplia rondando entre los 25 y 30 años, de momento en El Salvador no existe planta tan longeva y que sus equipos hayan culminado su vida útil, pero a medida transcurren los años, estos residuos serán generados en la industria a largo plazo y para poder mantener el prestigio de esta alternativa renovable es necesario contar con una buena gestión.Con la finalidad de contribuir a la buena gestión de esta problemática se realiza un análisis bibliográfico de la metodología de reutilización y reciclaje de paneles solares donde los resultados muestran que, en la actualidad las mejores opciones de implementación son los métodos de reciclaje térmico y químico, en contraste con el método mecánico, en base a los aspectos e impactos ambientales de cada uno de los procesos que conllevan los métodos descrito

Population and development in the Amazon: A longitudinal study of migrant settlers in the Northern Ecuadorian Amazon

ABSTRACT This paper examines changes over time for a full generation of migrant settlers in the Northern Ecuadorian Amazon (NEA). Data were collected from a 2014 household survey covering a subsample of households surveyed previously in 1990 and 1999. We observed changes in demographic behavior, land use, forest cover, and living conditions. As the frontier develops, human fertility is continuing to decline with contraceptive prevalence rising. Meanwhile, out-migration from colonist households, largely to destinations within the region, persists. More households have secure land tenure than in 1999, and are better off as measured by possession of assets. There is continued growth in pasture, largely at the expense of forest. Farms still serve as an important livelihood source for families, though growing cities in the NEA are creating more non-agricultural economic opportunities. Our findings provide a snapshot of demographic, economic, land use, and livelihood changes occurring in the NEA during the past quarter century, providing useful information for policymakers seeking to balance economic and environmental goals in order to promote sustainable development as well as protect biodiversity

S-acylation of the Wnt receptor Frizzled-5 by zDHHC5 controls its cellular localization and synaptogenic activity in the rodent hippocampus

Proper localization of receptors for synaptic organizing factors is crucial for synapse formation. Wnt proteins promote synapse assembly through Frizzled (Fz) receptors. In hippocampal neurons, the surface and synaptic localization of Fz5 is regulated by neuronal activity, but the mechanisms involved remain poorly understood. Here, we report that all Fz receptors can be post-translationally modified by S-acylation and that Fz5 is S-acylated on three C-terminal cysteines by zDHHC5. S-acylation is essential for Fz5 localization to the cell surface, axons, and presynaptic sites. Notably, S-acylation-deficient Fz5 is internalized faster, affecting its association with signalosome components at the cell surface. S-acylation-deficient Fz5 also fails to activate canonical and divergent canonical Wnt pathways. Fz5 S-acylation levels are regulated by the pattern of neuronal activity. In vivo studies demonstrate that S-acylation-deficient Fz5 expression fails to induce presynaptic assembly. Our studies show that S-acylation of Frizzled receptors is a mechanism controlling their localization and function

Herpetofauna de la cuenca baja del Río Temascatio, Irapuato, Guanajuato, México

México es considerado uno de los países con una de las diversidades de anfibios y reptiles más notables del mundo, con alrededor de 1,290 especies y con un alto grado de endemismo. Esto hace que la herpetofauna mexicana sea digna de analizarse bajo hipótesis taxonómicas, ecológicas y biogeográficas. En un contexto de diversidad de especies, el presente trabajo se enfoca en medir la composición y diversidad de anfibios y reptiles distribuidos en tres tipos de vegetación (bosque tropical caducifolio = BTC, matorral xerófilo = MX y bosque de encino = BE) presentes en la cuenca baja del Río Temascatio en el municipio de Irapuato, Guanajuato, México. La herpetofauna en la cuenca está compuesta por 14 familias, 23 géneros y 31 especies. Según el índice de Shannon-Wiener, el BE presentó el valor más alto de diversidad de especies (6.25), seguido por el BTC (5.29) y el MX (4.16). Las curvas de rango abundancia indicaron que, tanto en la estación de lluvias como en secas, la herpetofauna de la cuenca está integrada en su mayoría por especies raras y pocas especies abundantes. Según la Norma Oficial Mexicana NOM-059, tres especies de anuros y nueve de reptiles se encuentran bajo alguna categoría de riesgo. Solo una especie de anuro se encuentra catalogada como vulnerable de acuerdo con la lista roja de la IUCN. El EVS, índice que evalúa el estatus de vulnerabilidad ambiental de anfibios y reptiles mexicanos, considera a cuatro especies de anuros bajo riesgo alto, dos en riesgo medio, y cinco en riesgo bajo. Respecto a los reptiles, este índice ubica a seis especies en riesgo alto, seis en peligro medio, y ocho en riesgo bajo. Este trabajo representa el primer listado de la fauna de anfibios y reptiles de la cuenca baja del Río Temascatio, el cual puede ser considerado como base de información para desarrollar futuros estudios que involucren aspectos ecológicos y biogeográficos, encaminados a proponer estrategias de conservación de una fauna poco explorada en la porción noreste del Bajío mexicano.Mexico is considered one of the countries with one of the most notable diversities of amphibians and reptiles in the world, with around 1,290 species and a high degree of endemism. This makes Mexican herpetofauna worthy of analyse under taxonomic, ecological and biogeographic hypotheses. In a context of species diversity, the present work focuses on measuring the composition and diversity of amphibians and reptiles distributed in three types of vegetation (tropical deciduous forest = TDF, xerophytic scrub = XS and oak forest = OF) present in the Río Temascatio lower basin, municipality of Irapuato, Guanajuato, Mexico. The herpetofauna in the study area is composed of 14 families, 23 genera, and 31 species. According to the Shannon-Wiener index, the OF presented the highest value of species diversity (6.25), followed by the TDF (5.29) and the XS (4.16). The abundance range curves indicated that, both in the rainy and dry seasons, the herpetofauna of the basin is composed mostly of rare species and few abundant species. According to the Mexican regulation NOM-059, three species of anurans and nine species of reptiles are under some category of risk. Only one species of anuran is listed as vulnerable according to the IUCN Red List. The EVS, an index that evaluates the environmental vulnerability status of Mexican amphibians and reptiles, considers four species of anurans at high risk, two at medium risk, and five at low risk. For reptiles, this index places six species at high risk, six at medium risk, and eight at low risk. This work represents the first list of the amphibian and reptile fauna of the Río Temascatio lower basin, which can be considered as an information base for developing future studies involving ecological and biogeographical aspects, aimed at proposing conservation strategies for a little-explored fauna in the northeastern portion of the Mexican Bajío