Modelling potential distribution of the endemic ringtail (Bassariscus astutus saxicola) on an island of the Gulf of California

Objective: Analyze the topography of the island with a digital elevation model (DEM) at 30 m spatial resolution and generate the first distribution model for an endemic carnivore from the islands of the Gulf of California. Design/Methodology/Approach: This study employed the Maxent species distribution model to find the distribution of the ringtail in its habitat on Espíritu Santo Island. In 2015–2016, through four surveys, ringtails were trapped in eight glens on the west of the island. A total of 74 individuals were captured, with nine recaptures. Results: The variables with the greatest contributions to the models were elevation, contributing 71.6%; heat load index 15% and ruggedness 11.8%. The model predicts > 0.5 probabilities of presence of this carnivore in 3,018 hectares of the island. We obtained a high AUC value (0.928), which indicates that the model is accurate, and subsequently confirmed it with a value of pAUC = 1.917. Study Limitations/Implications: The habitat of the ringtail (Bassariscus astutus saxicola) was little known mainly because it is an endemic species. And there was not a published article that will show its distribution within the island. Conclusions: This model shows that topographic variables are useful to explain the potential distribution of the ringtail, mainly because the topography is related to sites that can offer thermal refuge, abundance of food, and escape routes from predators, among other features.Objetivo: Analizar la topografía de la isla mediante modelos digitales de elevación (DEM) con a 30 m de resolución espacial y generar el primer modelo de distribución potencial para un carnívoro endémico de las islas del Golfo de California. Diseño / Metodología / Enfoque: En este estudio se empleó el software Maxent para encontrar la distribución potencial del babisuri en la Isla Espíritu Santo. Los muestreos se realizaron en 2015–2016, los babisuris se muestrearon en ocho bahias en el oeste de la isla. Se capturaron un total de 74 individuos, con nueve recapturas. Resultados: Las variables con mayores aportes a los modelos fueron elevación, aportando 71.6%; índice de carga de calor el 15% y la rugosidad del 11.8%. El modelo predice> 0.5 probabilidades de presencia de este carnívoro en 3.018 hectáreas de la isla. Obtuvimos un valor alto de AUC (0.928), lo que indica que el modelo es exacto, y posteriormente lo confirmamos con un valor de pAUC = 1,917. Limitaciones / Implicaciones del estudio: El hábitat del babisuri (Bassariscus astutus saxicola) era poco conocido principalmente porque es una especie endémica. Y no existe un artículo publicado que muestre su distribución dentro de la isla. Conclusiones: Este modelo muestra que las variables topográficas son útiles para explicar la distribución potencial del babisuri, principalmente porque la topografía está relacionada con sitios que pueden ofrecer refugio termal, abundancia de alimento y rutas de escape de depredadores, entre otras características

Determinación de hormonas esteroides en heces de borrego cimarrón (Ovis canadensis Shaw) silvestres en Baja California, México

Objective: Determination of steroids hormones in wild bighorn sheep feces with a non-invasive method. Design/methodology/approach: In this study we analyze progestogens, androgens and estradiol, concentrations in wild bighorn sheep feces of Sierra San Felipe in Baja California during Spring, Winter and Summer seasons of the year 2007. Steroids were quantified by enzime immunoassay and evaluated using a micro titer plate. Results: With the hormonal profile it was identified that 96 feces were from males and 65 from females. The concentration of progestogens in the feces identified as females varied among the seasons of the year with spring being the highest concentration (280 ng/gr). Progestogen and estrogen concentrations in females increased as environmental conditions improved from winter to spring, coinciding with male androgen increase of 23.78 ng/gr. Limitations on study/implications: With this method it was not possible to assign the sex of samples that were identified as coming from juvenile individuals. We recommended to analyze fresh feces samples to relate the hormone concentrations with seasonal reproductive events. Findings/conclusions: The increase in progestogen and estrogen concentrations in feces of females and androgens in males during the spring suggests the initiation of reproductive activity. The concentrations of these hormones in both sexes during the summer are very low (<5 ng/gr), which suggests low reproductive activityObjetivo: Determinación de hormonas esteroides en heces de borrego cimarrón silvestre mediante un método no invasivo. Diseño / metodología / enfoque: En este estudio se detectaron progestágenos, andrógenos y estradiol en heces de borrego cimarrón silvestres que habitan en la Sierra San Felipe en Baja California, durante la primavera, invierno y verano del año 2007. Los esteroides se cuantificaron mediante inmunoensayo enzimático y la cuantificación se realizó en una placa de micro titulación. Resultados: Con el perfil hormonal se identificó que 96 eran heces provenientes de machos y 65 de hembras. La concentración de progestágenos en las heces identificadas como hembras varió entre las estaciones del año siendo la primavera con la concentración más alta (280 ng/gr). Las concentraciones de progestágenos y estrógenos en las hembras aumentaron a medida que las condiciones ambientales mejoraron desde el invierno hasta la primavera, coincidiendo con el aumento de andrógenos en los machos de 23.78 ng / gr. Limitaciones en el estudio / implicaciones: con este método no fue posible asignar el sexo de las muestras que se identificaron que provienen de individuos juveniles. Se recomienda analizar muestras de heces frescas para relacionar las concentraciones de hormonas con eventos reproductivos estacionales. Hallazgos / conclusiones: El aumento de las concentraciones de progestágenos y estrógenos en las heces de las hembras y los andrógenos en los machos en la primavera sugiere el inicio de la actividad reproductiva. Las concentraciones de estas hormonas en ambos sexos durante el verano son muy bajas (<5 ng / gr), lo que sugiere una actividad reproductiva baja. &nbsp

Multitemporal distribution analysis of Dodonaea viscosa (L.) Jacq. by remote sensing in Durango, Mexico

Objective: To determine the distribution of D. viscosa at the Guadalupe Victoria dam for the years 1990, 2010 and 2017. Design/methodology/approach: Landsat satellite images were processed in order to perform a supervised classification using an artificial neural network. The ground cover of pastures, crops, shrubs and oak forest was estimated from images for the years 1990, 2010 and 2017 at sites where the presence of D. viscosa had been recorded. These data were used to calculate the expansion of D. viscosa in the study area. Results: Limitations on study/implications: The supervised classification of the artificial neural network was optimal after 400 iterations, obtaining the best overall precision, 84.5%, for 2017. This contrasted with 1990, where overall precision was low, at 45%, because there were few training sites (fewer than 100) recorded for each of the land cover classes. Findings/conclusions: In 1990, D. viscosa was found on only five hectares, while by 2017 it had increased to 147 hectares. If the disturbance caused by overgrazing continues, the potential distribution projected for D. viscosa shows it invading half the study area, occupying agricultural, forested and scrub areas.Objective: to determine the distribution of D. viscosa in the vicinity of the Guadalupe Victoria Dam in Durango, Mexico, for the years 1990, 2010 and 2017.Design/Methodology/Approach: Landsat satellite images were processed in order to carry out supervised classifications using an artificial neural network. Images from the years 1990, 2010 and 2017 were used to estimate ground cover of D. viscosa, pastures, crops, shrubs, and oak forest. This data was used to calculate the expansion of D. viscosa in the study area.Results/Study Limitations/Implications: the supervised classification with the artificial neural network was optimal after 400 iterations, obtaining the best overall precision of 84.5 % for 2017. This contrasted with the year 1990, when overall accuracy was low at 45 % due to less training sites (fewer than 100) recorded for each of the land cover classes.Findings/Conclusions: in 1990, D. viscosa was found on only five hectares, while by 2017 it had increased to 147 hectares. If the disturbance caused by overgrazing continues, and based on the distribution of D. viscosa, it is likely that in a few years it will have the ability to invade half the study area, occupying agricultural, forested, and shrub area

Variabilidad en el contenido de polifenoles, actividad biológica y antihelmíntica de extractos metanol:agua de las hojas de Gymnopodium floribundum Rolfe

The effect of the harvest month and age of the leaves of Gymnopodium floribundum on the content of polyphenolic compounds (total phenols (TP), total tannins (TT) and condensed tannins (CT)) of methanol:water extracts was determined. In addition, the biological activity of polyphenols measured as the ability to precipitate protein (PP), inhibit egg hatching (EH), and larval exsheathment (LEI) of Haemonchus contortus was determined. G. floribundum leaves were harvested in 4 mo of the year: December, March, June and September. Twenty-four methanol:water extracts (70:30) were obtained, 12 produced from leaves of varied age (VA) and 12 from 90-d-old leaves (A90). All extracts caused similar PP regardless of age and harvest month. EH inhibition was only significant for December VA extract (EC50 = 374.4 μg/mL; P 1,500 μg/mL in December, June and September. Although all extracts inhibited larval exsheathment (LEI), the lowest EC50 was that of the VA leaf extract of June (EC50 = 80.4 μg/mL; P 1500 μg/ml en diciembre, junio y septiembre. Aunque todos los extractos inhibieron el desenvaine larval (IDL), la menor CE50 fue la del extracto de hojas EV de junio (CE50 = 80.4 μg/ml; P<0.05). La incubación de extractos con polivinilpolipirrolidona (PVPP) limitó la IDL (P<0.05), pero los polifenoles solo explicaron parte de esa actividad. En conclusión, el contenido de TC de los extractos de hojas de G. floribundum depende de su edad y mes de cosecha. Los polifenoles mostraron actividad de PP y se asociaron parcialmente con la IDL. Sin embargo, los polifenoles no explican la actividad contra huevos de H. contortus

Bio-guided fractionation to identify Senegalia gaumeri leaf extract compounds with anthelmintic activity against Haemonchus contortus eggs and larvae

Small ruminants browsing in tropical forests readily consume the foliage of Senegalia gaumeri. A S. gaumeri methanol:water extract was recently shown to have ovicidal activity against Haemonchus contortus eggs in vitro. In the present study, the fraction of a S. gaumeri methanol:water extract with ovicidal activity against H. contortus eggs and the metabolites potentially involved in this activity were identified. Bio-guided fractionation of the S. gaumeri methanol:water extract identified high ovicidal activity (80.29%, EC50 = 58.9 μg/mL) in the non-polar sub-fraction P1. Gas chromatography-mass spectrometry (GC–MS) identified several fatty acids: pentacosane (18.05%), heneicosane (18.05%), triacontane (30.94%), octacosane (18.05%), and hexanedioic acid bis-(2-ethylhexyl) ester (32.72%). Purification of the polar components of sub-fraction P1 led to the identification of p-coumaric acid as a major constituent. In egg hatch tests, 400 μg/mL p-coumaric acid resulted in an ovicidal effect of 8.7%, a larvae failing eclosion effect of 2.9%, and of the emerged larvae (88.4%), many were damaged. In conclusion, the low AH activity of p-coumaric acid against H. contortus eggs indicates that it is not solely responsible for the ovicidal activity of sub-fraction P1 but might act in synergy with other compounds in this fraction. However, p-coumaric acid showed potential anthelmintic effects against the larval stage of H. contortus

Diseño e implementación de un prototipo de timbre electrónico programable para el correcto control de las horas clases en el centro educativo Monte Sinaí

Presenta la propuesta de información sobre los dispositivos que se puedan utilizar en el desarrollo y construcción del prototipo, también destaca algunos proyectos que se han realizado en diversos países en los que se proponen diseños similares al de este trabajo

Estimación del riesgo en reactores químicos con descontrol térmico

A large number of reactions carried out in the chemical industry are exothermic, where temperature control is achieved by means of the removal of heat using jackets or internal cooling coils. However, thermal runaway can occur as a result of the inability to remove sufficient amount of heat in the reaction system causing the explosion and release of large quantities of toxic and/or flammable gases in the atmosphere with negative consequences for workers or populations in the nearby area. In this work, a quantitative risk analysis was applied to quantify the risk of the process under the different scenarios generated. The risk analysis is based on mathematical models that describe the chemical process. We analyze the case study that consists of a semi-continuous reactor where oxidation occurs in nitric acid of 2-octanol to produce 2-octanone. The analysis of consequences has the objective of estimating the number of damages and fatalities that occur in a population exposed to toxic substances. The methodology applied in this work made it possible to investigate the effect of the deviation of a process variable in the reactor over the risk of fatality, analyzing three different scenarios.Una gran cantidad de reacciones que se llevan a cabo en la industria química, son exotérmicas, donde el control de la temperatura se logra por medio de la remoción de calor usando chaquetas o serpentines de enfriamiento internos. Sin embargo, puede ocurrir el descontrol térmico como consecuencia de la incapacidad para remover suficiente cantidad de calor en el sistema de reacción causando la explosión y liberación de grandes cantidades de gases tóxicos y/o inflamables en la atmósfera con consecuencias negativas para trabajadores o incluso habitantes cercanos en la zona. En este trabajo se aplicó un análisis cuantitativo de riesgos para cuantificar el riesgo del proceso bajo los diferentes escenarios generados. El análisis de riesgo está basado en modelos matemáticos que describen el proceso químico. Se analiza el caso de estudio que consiste en un reactor semi-continuo en donde se produce la oxidación en ácido nítrico de 2-octanol para producir 2-octanona. El análisis de consecuencias tiene el objetivo de estimar el número de daños y fatalidades que ocurren en una población expuesta a sustancias tóxicas. La metodología aplicada en este trabajo permitió investigar el efecto de la desviación de una variable de proceso en el reactor sobre el riesgo de fatalidad, analizando tres diferentes escenarios