A rapid method for isolation of total DNA from pathogenic filamentous plant fungi

DNA isolation from some fungal organisms of agronomic importance is difficult because they have cell walls or capsules that are relatively unsusceptible to lysis. We have developed a fast DNA isolation protocol for Fusarium oxysporum, which causes fusarium wilt disease in more than 100 plant species, and for Pyrenochaeta terrestris, which causes pink root in onions. This protocol was based on the sodium dodecyl sulfate/ phenol method, without β-mercaptoethanol and without maceration in liquid nitrogen; it uses phenol/chloroform extraction to remove proteins and co-precipitated polysaccharides. The A260/280 absorbance ratios of isolated DNA were around 1.9, suggesting that the DNA fraction was pure and may be used for further analysis. Additionally, the A260/230 values were higher than 1.8, suggesting negligible contamination by polysaccharides. The DNA isolated by this protocol is of sufficient quality for molecular applications; this technique could be applied to other organisms that have similar substances that hinder DNA extraction

Durinskia yucatanensis sp. nov. (Peridiniales: Kryptoperidiniaceae), una nueva especie de dinoflagelado planctónico, y su hábitat en aguas costeras de Yucatán, Golfo de México

Background: In the coastal waters of the northern Yucatan Peninsula, in the southeastern Gulf of Mexico, numerous pelagic algal blooms have been recorded in the 21st century. In August 2010, an unknown small-sized Peridiniales species caused an intense bloom in the Sisal marina. In subsequent years, it was occasionally found at other sites along the Yucatan coast. Goals: The main objective of the present study was to name this dinoflagellate as a new species and determine its ecological preferences. Methods: Phytoplankton blooms were monitored from August 2011 to September 2014. Fixed cells of the studied species were examined in a JEOL JSM-7600F scanning electron microscope. Its ecological preferences were evaluated using multivariate permutational analysis and generalized additive models (GAM). Results: The name Durinskia yucatanensis (Dinophyceae: Peridiniales) with the thecal plate formula Po X 4’ 2a 6” 5c 4s(?) 5”’ 2”” is proposed for a previously recorded Kryptoperidiniaceae species from the northern Yucatan coastal waters. Dissolved inorganic nitrogen positively correlated with cell abundances for both the exposed coast and marinas, especially in July-August, characterized by high water temperature (31-32 °C). Chlorophyll-a was the only parameter that presented significant spatio-temporal variability among years, months, and sampling sites. The GAM showed that temperature and salinity can predict changes in abundance in different study zones (exposed coast and marinas). The highest values were observed in the Progreso-Chicxulub area along the exposed coast in 2011 and only at Dzilam in marinas during all studied years. Conclusions: The species appears to prefer eutrophic conditions typical for marinas along the northern coast of Yucatan.Antecedentes: En las aguas costeras del norte de la península de Yucatán, en el sureste del Golfo de México, numerosos florecimientos pelágicos de microalgas se han registrado en el siglo 21. En agosto de 2010, una especie pequeña y desconocida de Peridiniales causó un florecimiento intenso en el puerto de abrigo de Sisal. En los años siguientes, se encontró ocasionalmente en otros sitios a lo largo de la costa de Yucatán. Objetivo: Nombrar a este dinoflagelado como una especie nueva para la ciencia y determinar sus preferencias ecológicas. Métodos: Los florecimientos de fitoplancton fueron monitoreados desde agosto de 2011 hasta septiembre de 2014. Las células se examinaron en un microscopio electrónico de barrido JEOL JSM-7600F. Sus preferencias ecológicas se evaluaron mediante análisis permutacional multivariante y modelos aditivos generalizados (GAM). Resultados: El nombre Durinskia yucatanensis (Dinophyceae: Peridiniales), cuya fórmula de placa tecal Po X 4’ 2a 6” 5c 4s(?) 5”’ 2””, se propone para una especie de Kryptoperidiniaceae previamente registrada de las aguas costeras del norte de Yucatán. El nitrógeno inorgánico disuelto se correlacionó positivamente con la abundancia de células, tanto para la costa expuesta como para los puertos deportivos, especialmente en julio-agosto, caracterizados por una alta temperatura del agua (31-32 °C). La clorofila-a fue el único parámetro que presentó variabilidad espacio-temporal significativa entre años, meses y sitios de muestreo. Los GAM demostraron que la temperatura y la salinidad pueden predecir cambios en la abundancia en diferentes zonas de estudio (costa expuesta y puertos deportivos). Los valores más altos se observaron en el área de Progreso-Chicxulub a lo largo de la costa expuesta en 2011 y solo en Dzilam en marinas durante todos los años estudiados. Conclusiones: La especie parece preferir las condiciones eutróficas típicas de los puertos deportivos a lo largo de la costa norte de Yucatán

Mamíferos silvestres de la Reserva Ecológica del Pedregal de San Ángel en Ciudad Universitaria, Universidad Nacional Autónoma de México, México, D. F. Wild mammals of Reserva Ecológica del Pedregal de San Ángel, Ciudad Universitaria, UNAM, Mexico, D.F.

Se realizó un inventario de las especies de mamíferos que habitan en la Reserva Ecológica del Pedregal de San Ángel (REPSA). Los datos se obtuvieron a partir de registros de colecciones científicas, de recolectas recientes en el área y de consultas en literatura especializada. Los resultados comprenden 628 registros acumulados desde 1943 y corresponden a 33 especies, agrupadas en 28 géneros, 15 familias y 6 órdenes de mamíferos. La ardilla gris (Sciurus aureogaster nigrescens) y el ratón del altiplano (Peromyscus melanophrys melanophrys) se registran por primera vez para la REPSA; asimismo, existen 2 registros que están publicados pero no listados en los inventarios previos a la reserva, el murciélago colorado, Lasiurus blossevillii teliotis, y el cuinique, Spermophilus adocetus adocetus; en las categorías de riesgo se encuentran como amenazadas 2 especies y 1 en la de protección especial, y hay 7 endémicas de México. La Reserva es uno de los últimos reductos de material genético de especies cuya localidad tipo se encuentra en la cuenca de México. El componente mastofaunístico de la zona es importante para el mantenimiento de la biodiversidad, por lo que el estudio y la protección de este ecosistema al interior de la ciudad de México debe continuarse.<br>This paper documents the mammals from the Reserva Ecológica del Pedregal de San Ángel. Data were gathered from records in mammal collections, the specialized literature, and through collecting efforts in the area. Records spanning 1943 to the present document the presence of 33 species, 28 genera, 15 families, and 6 orders of mammals. One squirrel and one mouse (Sciurus aureogaster nigrescens, and Peromyscus m. melanophrys) are reported for the first time for the reserve. Two addtional records have been previously published but have not been included in previous inventories for the reserve: the red bat, Lasiurus blossevillii teliotis and the cuinique, Spermophilus adocetus adocetus. Two species are currently listed under the risk category of threatened, 1 is under special protection, and 7 are endemic to Mexico. This mammal component is important for the ecosystem of the area and the conservation of biodiversity. The richness of mammals of the area deserves efforts to conserve and preserve the biodiversity of this unique ecosystem within México City

Projected impact of COVID-19 mitigation strategies on hospital services in the Mexico City Metropolitan Area

Evidence-based models may assist Mexican government officials and health authorities in determining the safest plans to respond to the coronavirus disease 2019 (COVID-19) pandemic in the most-affected region of the country, the Mexico City Metropolitan Area. This study aims to present the potential impacts of COVID-19 in this region and to model possible benefits of mitigation efforts. The COVID-19 Hospital Impact Model for Epidemics was used to estimate the probable evolution of COVID-19 in three scenarios: (i) no social distancing, (ii) social distancing in place at 50% effectiveness, and (iii) social distancing in place at 60% effectiveness. Projections of the number of inpatient hospitalizations, intensive care unit admissions, and patients requiring ventilators were made for each scenario. Using the model described, it was predicted that peak case volume at 0% mitigation was to occur on April 30, 2020 at 11,553,566 infected individuals. Peak case volume at 50% mitigation was predicted to occur on June 1, 2020 with 5,970,093 infected individuals and on June 21, 2020 for 60% mitigation with 4,128,574 infected individuals. Occupancy rates in hospitals during peak periods at 0%, 50%, and 60% mitigation would be 875.9%, 322.8%, and 203.5%, respectively, when all inpatient beds are included. Under these scenarios, peak daily hospital admissions would be 40,438, 13,820, and 8,650. Additionally, 60% mitigation would result in a decrease in peak intensive care beds from 94,706 to 23,116 beds and a decrease in peak ventilator need from 67,889 to 17,087 units. Mitigating the spread of COVID-19 through social distancing could have a dramatic impact on reducing the number of infected people and minimize hospital overcrowding. These evidence-based models may enable careful resource utilization and encourage targeted public health responses

Numerical and Physical Parametric Analysis of a SEN with Flow Conditioners in Slab Continuous Casting Mold

Some of the most recent technologies that improves the performance in continuous casting process has installed infrastructure outside the mold to modify the natural fluid flow pattern to obtain a quasi-steady condition and promote a uniform solidified shell of steel. The submerged entry nozzle distributes the liquid steel in the mold and can be used to obtain the flow symmetry condition with external geometry improvements. The fluid flow conditioners were located near the outlet ports of the nozzle. The aim of the modifiers is to impose a pseudo symmetric pattern in the upper zone of the mold by inhibiting the fluid exchange between the zones created by conditioners. This work evaluates the effect of the thickness and length of the fluid-flow modifiers on the overall performance of the submerged nozzle. These properties of the fluid-flow modifiers were normalized based on two of the geometric dimensions of the standard equipment. Numerical and physical simulations suggest that the flow modifier should be as thin as possible

Influence of Geometry and Velocity of Rotating Solids on Hydrodynamics of a Confined Volume

Three cylinder-based geometries were evaluated at five different rotating speeds (ω = 20.94, 62.83, 94.25, 125.66, and 157.08 rad·s−1) to obtain the fluid flow pattern in nonsteady conditions. Two of the models were modified at the lower region, also known as tip section, by means of inverted and right truncated cone geometries, respectively. The experimental technique used a visualization cell and a Particle Imaging Velocimetry installation to obtain the vector field at the central plane of the volume. The Line Integral Convolution Method was used to obtain the fluid motion at the plane. In addition, the scalar kinetic energy and the time series were calculated to perform the normal probability plot. This procedure was used to determine the nonlinear fluid flow pattern. It was also used to identify two different flow regimens in physical and numerical results. As the rotation speed increased, the turbulent regions were placed together and moved. The process makes experimental observation difficult. The biphasic and turbulence constitutive equations were solved with the Computational Fluid Dynamics technique. Numerical results were compared with physical experiments for validation. The model with the inverted truncated cone tip presented better stability in the fluid flow pattern along the rotation speed range

Fire History (1896–2013) in an Abies religiosa Forest in the Sierra Norte of Puebla, Mexico

The oyamel forests, as Abies dominated forests are commonly known as, register their largest distribution (95% of their population) along the Trans-Mexican Volcanic Belt (TMVB). Although efforts have been made to study these forests with various approaches, dendrochronology-based studies have been limited, particularly in pure Abies forests in this region. The objective of this study was to reconstruct fire regimes in an Abies religiosa forest in the Sierra Norte in the state of Puebla, Mexico. Within an area of 50-ha, we collected 40 fire-scar samples, which were processed and analyzed using dendrochronological techniques to identify 153 fire scars. The fire history was reconstructed for a period of 118 years (1896–2013), with low severity surface fires occurring mainly during in the spring (92.8%) and summer (7.2%). Over the past century, fires were frequent, with an mean fire interval (MFI) and Weibull median probability of (WMPI) of five years when considering all fire scars and less than 10 years for fires covering larger areas (fires recorded by ≥25% of samples). Extensive fires were synchronized with drought conditions based on Ring Width Indexes, Palmer Drought Severity Index (PDSI) and El Niño Southern Oscillation (ENSO). After 1983, we observed a change in fire frequencies attributed to regulated management. Longer fire intervals within the last several decades are likely leading to increased fuel accumulations and could potentially result in more severe fires in the future, threatening the sustainability of these forests. Based on our finding, we recommend management actions (silvicultural or prescribed fire) to reduce fuels and the risk of severe fires, particularly in the face of climatic changes

‘‘It’s okay because I’m just driving’’: an exploration of self-reported mobile phone use among Mexican drivers

Introduction. Technological advancements have the potential to enhance people’s quality of life, but their misuse can have a detrimental impact on safety. A notable example is the escalating issue of distracted driving resulting from the use of mobile phones behind the wheel, leading to severe crashes and injuries. Despite these concerns, both drivers’ usage patterns and their risk-related associations remain scarcely documented in Mexico. Therefore, this descriptive study aimed to examine the mobile phone usage of Mexican drivers, its relationships to risk awareness and near-miss/crash involvement, and the self-reported underlying reasons for this behavior. Methods. This cross-sectional study utilized a sample of 1,353 licensed Mexican drivers who took part in a nationwide series of interviews regarding their onboard phone use settings. Results. A significant percentage of drivers (96.8%) recognize using a mobile phone while driving as high-risk behavior. However, only 7.4% reported completely avoiding its use while driving, with 22.4% identified as high-frequency users. Frequency was also found positively associated with the self-reported rate of near-misses and crashes. Furthermore, qualitative data analysis highlights the emergence of a ‘sense of urgency’ to attend to phone-related tasks in response to daily demands and life dynamics, offering a potential explanation for this behavior. Conclusion. The results of this study suggest common patterns of onboard mobile use among Mexican drivers concerning driving situations and associated risks. This underscores the need for increased efforts to discourage onboard phone use in the country.Safety and Security Scienc

Diagnóstico de la maquinaria agrícola en Amecameca y Texcoco, Estado de México.

The objective of the study was to perform a diagnosis of the agricultural machinery and to obtain the mechanization index in the region of Amecameca and Texcoco, Estado de México. The study subjects were agricultural producers who benefited from government programs in 1996 to 2006. A survey was applied to 133 producers who were selected through a stratified probabilistic sample. The results indicate that the average surface where a tractor is used is lower (27.8 ha tractor-1 ) than recommended by FAO (2011) (50 ha tractor-1 ); the mechanization index in Amecameca and Texcoco is 6.4 and 4.6 hp ha-1, respectively, which indicates that there is a high level of mechanization. According to Gaytán (2007), the level recommended is 1 hp ha-1. It was detected that the level of knowledge to operate agricultural equipment efficiently was deficient; 75.2 % of the users of agricultural machinery said they had not been trained at the moment of acquiring the new equipment, while 24.8% had received general training at the time of acquiring their machine. The knowledge they have has been obtained throughout time through trial and error, or as knowledge transferred by family members, workmates or neighbors.El objetivo del estudio realizar un diagnóstico de la maquinaria agrícola y obtener el índice de mecanización en la región de Amecameca y Texcoco, Estado de México. Los sujetos de estudio fueron los productores agrícolas beneficiados por programas de gobierno de 1996 a 2006. Se aplicó una encuesta a 133 productores que fueron seleccionados por medio de un muestreo probabilístico estratificado. Los resultados indican que la superficie promedio que utiliza un tractor es menor (27.8 ha tractor-1 ) a la recomendada por FAO (2011) (50 ha tractor-1 ); el índice de mecanización en Amecameca y Texcoco es de 6.4 y 4.6 hp ha-1 ,respectivamente, lo que indica que existe un nivel de mecanizacion elevado. De acuerdo con Gaytán (2007), el recomendado es de 1 hp ha-1. Se detectó que el nivel de conocimientos para operar eficientemente un equipo agrícola era deficiente; 75.2 % de los usuarios de la maquinaria agrícola dijeron no haber sido capacitados al momento de adquirir un equipo nuevo, mientras que 24.8 % había recibido capacitación general al momento de adquirir su maquinaria. Los conocimientos con que cuentan han sido obtenidos a través del tiempo mediante prueba y error, o conocimientos transferidos por familiares, compañeros o vecinos