Caracterización de hongos micorrícicos del género Tulasnella (Tulasnellaceae : Basidiomycota) en el género de orquídeas Bletia de la Reserva Natural Barranca del Cupatitzio, México

The goal of this study was the identification of mycorrhizal fungi associated with three terrestrial orchids of the genus Bletia Ruiz & Pav.: B. roezlii Rchb. f., B. purpurata A.Rich., and B. punctata Lex., in Barranca del Cupatitzio Natural Reserve - Michoacán, México - . Thirty-nine strains were isolated and morphologically characterized. Nine strains were selected from the molecular analysis. Bletia punctata, an endemic species of Mexico, showed the lowest variability in mycorrhizal fungi. Morphological analysis showed that 39 isolated strains belong to the ‘Rhizoctonia-like fungal complex’. According with the tree of Euclidian distances generated by the analysis WARD, all isolates were included into four subgroups, all related to the genus Tulasnella J.Schröt - which belongs to the ‘Rhizoctonia-like fungal complex’?. Molecular and phylogenetic analysis of the nine selected strains corroborated the results of the morphological study: the sequences obtained were clustered in four subclades related to species of Tulasnella. Our results indicate that a single species of Bletia from a single locality can be associated with different species of mycorrhizal fungi, at least during the adult stage and that the combination of morphological and molecular analyses is a good tool to identify orchid mycorrhizal fungi.Este estudio tuvo por objetivo la identificación de hongos micorrícicos asociados a tres especies de orquídeas terrestres del género Bletia Ruiz & Pav.: B. roezlii Rchb. f., B. purpurata A.Rich. y B. punctata Lex. en la Reserva Natural Barranca del Cupatitzio -Michoacán, México-. Treinta y nueve cepas fueron aisladas y caracterizadas morfológicamente, de las que nueve se seleccionaron para el análisis molecular. Bletia punctata, endémica de México, presentó la menor variabilidad de morfotipos de hongos micorrícicos. El análisis morfológico demostró que todos los aislamientos pertenecen al ‘complejo Rhizoctonia’. De acuerdo con el árbol de distancias euclídeas generado mediante análisis WARD, todas las cepas se agruparon en cuatro subgrupos, todos relacionados con el género Tulasnella J.Schröt -que pertenece al ‘complejo Rhizoctonia’-. Los análisis molecular y filogenético de las nueve cepas seleccionadas corroboraron los resultados del estudio morfológico: las secuencias obtenidas se distribuyeron en cuatro subclados relacionados con especies de Tulasnella. Nuestros resultados indican que una misma especie de Bletia puede asociarse al mismo tiempo con varias especies de hongos micorrícicos, al menos durante la etapa adulta, y que la combinación de análisis morfológicos y moleculares es una herramienta útil para la identificación de hongos micorrícicos en orquídeas

Modelo hidrodinámico en el Sistema Lagunar Navachiste, Guasave, Sinaloa, México

The Navachiste Lagoon System is connected to the Gulf of California (GC) via 3 tidal channels. The system has an area of approximately 301 km2, with an average depth of 2.5 m and an average tide height of 1.5 m. In order to simulate tidal currents and the effect of wind, a numerical hydrodynamic model was applied, integrated in the vertical and in finite differences; to calibrate the model, lagrangean measurements were made and compared with simulated currents in the tidal channels of the system. The model simulates the hydrodynamic behavior of the lagoon system and has a correlation higher than 85% with the trajectories traced by the drift bodies and with the maximum Eulerian velocities measured in the internal channels and in the mouths of the system.El Sistema Lagunar Navachiste se encuentra conectado con el Golfo de California (GC) a través de 3 canales de marea. El sistema cuenta con un área de 301 km2 aproximadamente, con una profundidad promedio de 2,5 m y una altura de mareas promedio de 1,5 m. Para simular las corrientes de mareas y el efecto del viento se aplicó un modelo hidrodinámico numérico barótropico, integrado en la vertical y en diferencias finitas; para calibrar el modelo se hicieron mediciones lagrangeanas y se compararon con las corrientes simuladas en los canales de marea del sistema. El modelo simula el comportamiento hidrodinámico del sistema lagunar y presenta una correlación superior al 85% con las trayectorias trazadas por los cuerpos de deriva y con las velocidades máximas eulerianas medidas en los canales internos y en las bocas del sistema

Methylmercury exposure in a subsistence fishing community in Lake Chapala, Mexico: an ecological approach

<p>Abstract</p> <p>Background</p> <p>Elevated concentrations of mercury have been documented in fish in Lake Chapala in central Mexico, an area that is home to a large subsistence fishing community. However, neither the extent of human mercury exposure nor its sources and routes have been elucidated.</p> <p>Methods</p> <p>Total mercury concentrations were measured in samples of fish from Lake Chapala; in sections of sediment cores from the delta of Rio Lerma, the major tributary to the lake; and in a series of suspended-particle samples collected at sites from the mouth of the Lerma to mid-Lake. A cross-sectional survey of 92 women ranging in age from 18-45 years was conducted in three communities along the Lake to investigate the relationship between fish consumption and hair mercury concentrations among women of child-bearing age.</p> <p>Results</p> <p>Highest concentrations of mercury in fish samples were found in carp (mean 0.87 ppm). Sediment data suggest a pattern of moderate ongoing contamination. Analyses of particles filtered from the water column showed highest concentrations of mercury near the mouth of the Lerma. In the human study, 27.2% of women had >1 ppm hair mercury. On multivariable analysis, carp consumption and consumption of fish purchased or captured from Lake Chapala were both associated with significantly higher mean hair mercury concentrations.</p> <p>Conclusions</p> <p>Our preliminary data indicate that, despite a moderate level of contamination in recent sediments and suspended particulate matter, carp in Lake Chapala contain mercury concentrations of concern for local fish consumers. Consumption of carp appears to contribute significantly to body burden in this population. Further studies of the consequences of prenatal exposure for child neurodevelopment are being initiated.</p

Application of Optimum Compaction Energy in the Development of Bricks Made with Construction Trash Soils

In general, bricks frequently show different densities and therefore different resistances because the compaction energy is not considered in their production. Expansive soils represent a problem for light buildings over them because of volumetric instability. A generalized solution has been to extract them and substitute them by inert soil; thus they become construction trash. So, in this work the compaction energy aspect and the use of construction trash soils in the elaboration of resistant masonry bricks of homogeneous and controlled density are a new contribution in the production of bricks of better quality. First, the soil was stabilized with CaOH which leads to a decrease in its volumetric changes. Then, they were compacted with a specific energy for obtaining an optimal and maximum controlled density to ensure an increase in strength. Our results show that two optimal compaction energies can be considered with respect to the variation of optimum moisture in masonry bricks of expansive soil stabilized with lime. The first is when the optimal humidity reaches its smallest value (integrated soil lumps) and the second is when humidity increases (disintegrated soil lumps), after reaching its lowest value. We also conclude that high compaction energy does not improve density values

A Workshop on Cognitive Aging and Impairment in the 9/11-Exposed Population

The terrorist attacks on 11 September 2001 potentially exposed more than 400,000 responders, workers, and residents to psychological and physical stressors, and numerous hazardous pollutants. In 2011, the World Trade Center Health Program (WTCHP) was mandated to monitor and treat persons with 9/11-related adverse health conditions and conduct research on physical and mental health conditions related to the attacks. Emerging evidence suggests that persons exposed to 9/11 may be at increased risk of developing mild cognitive impairment. To investigate further, the WTCHP convened a scientific workshop that examined the natural history of cognitive aging and impairment, biomarkers in the pathway of neurodegenerative diseases, the neuropathological changes associated with hazardous exposures, and the evidence of cognitive decline and impairment in the 9/11-exposed population. Invited participants included scientists actively involved in health-effects research of 9/11-exposed persons and other at-risk populations. Attendees shared relevant research results from their respective programs and discussed several options for enhancements to research and surveillance activities, including the development of a multi-institutional collaborative research network. The goal of this report is to outline the meeting’s agenda and provide an overview of the presentation materials and group discussion

Gliomas and Farm Pesticide Exposure in Women: The Upper Midwest Health Study

An excess incidence of brain cancer in male farmers has been noted in several studies, but few studies have focused on women. The National Institute for Occupational Safety and Health Upper Midwest Health Study evaluated effects of rural exposures for 341 female glioma cases and 528 controls, all adult (18–80 years of age) nonmetropolitan residents of Iowa, Michigan, Minnesota, and Wisconsin. On average, controls lived longer on farms than did cases. After adjusting for age, age group, education, and farm residence, no association with glioma was observed for exposure to arsenicals, benzoic acids, carbamates, chloroacetanilides, dinitroanilines, inorganics, organochlorines, organophosphates, phenoxys, triazines, or urea-based or estrogenic pesticides. An increased risk of glioma was observed for carbamate herbicides but was not statistically significant (odds ratio = 3.0; 95% confidence interval, 0.9–9.5). No association was observed between glioma and exposure to 12 widely used specific pesticides, after adjustment for age, age group, education, and any other pesticide exposure. These results were not affected after exclusion of proxy respondents (43% of cases, 2% of controls). Women were less likely than men to have applied pesticides, but more likely to have laundered pesticide-contaminated clothes. Storing pesticides in the house was associated with a statistically non-significant increased risk. Results show that exposure to pesticides was not associated with an increased risk of intracranial gliomas in women. Other farm-related factors could be etiologic factors and will be discussed in future reports

Epidemiological and some clinical characteristics of neuroblastoma in Mexican children (1996–2005)

<p>Abstract</p> <p>Background</p> <p>Neuroblastoma (NB) is the principal tumor of the sympathetic nervous system in children under one year of age. The incidence in developed countries is greater than that in developing countries. The aim of this article is to present the epidemiological and some clinical characteristics of Mexican children with NB.</p> <p>Methods</p> <p>A population-based, prolective study, with data obtained from the Childhood Cancer Registry of the Instituto Mexicano de Seguro Social. Statistical analysis: The simple frequencies of the variables of the study and the annual average incidence (per 1,000,000 children/years) by age and sex were obtained. The trend was evaluated by calculating the annual percentage of change. The curves of Kaplan-Meyer were employed for the survival rate and the log-rank test was used to compare the curves.</p> <p>Results</p> <p>Of a total of 2,758 children with cancer registered during the period from 1996–2005, 72 (2.6%) were identified as having Group IV, defined according to the International Classification of Childhood Cancer. The incidence for NB was 3.8 per 1,000,000 children/year; NB was highest in the group of children under one year of age, followed by the group of children between the ages 1–4 years (18.5 and 5.4 per 1,000,000 children/years, respectively). The male/female ratio was 1.1 and there was no trend toward an increase. The time of diagnosis was 26 days (median), but varied according to the stage at diagnosis. Stages III and IV were presented in 88% of the cases. There was no association between the stage, the age at time of diagnosis, or the histological pattern. The overall five-year survival rate was 64%; the patients with stage I, II, III, or IVs did not die; and the five-year survival rate of cases in Stage IV was 40%.</p> <p>Conclusion</p> <p>It is possible that the low incidence of neuroblastoma in Mexican children is due to the difficulty in diagnosing the cases with the best prognosis, some of which could have had spontaneous regression. There was no trend to an increase; the majority of the cases were diagnosed in the advanced stages; and the overall five-years survival rate was similar to that for developed countries.</p

Socially and biologically inspired computing for self-organizing communications networks

The design and development of future communications networks call for a careful examination of biological and social systems. New technological developments like self-driving cars, wireless sensor networks, drones swarm, Internet of Things, Big Data, and Blockchain are promoting an integration process that will bring together all those technologies in a large-scale heterogeneous network. Most of the challenges related to these new developments cannot be faced using traditional approaches, and require to explore novel paradigms for building computational mechanisms that allow us to deal with the emergent complexity of these new applications. In this article, we show that it is possible to use biologically and socially inspired computing for designing and implementing self-organizing communication systems. We argue that an abstract analysis of biological and social phenomena can be made to develop computational models that provide a suitable conceptual framework for building new networking technologies: biologically inspired computing for achieving efficient and scalable networking under uncertain environments; socially inspired computing for increasing the capacity of a system for solving problems through collective actions. We aim to enhance the state-of-the-art of these approaches and encourage other researchers to use these models in their future work

Incidence of cancer in children residing in ten jurisdictions of the Mexican Republic: importance of the Cancer registry (a population-based study)

BACKGROUND: In 1996, Mexico started to register cases of childhood cancer. Here, we describe the incidence of cancer in children, residing in ten Mexican jurisdictions, who were treated by the Instituto Mexicano del Seguro Social (IMSS). METHODS: New cases of childhood cancer, which were registered prospectively in nine principal Medical Centers of IMSS during the periods 1998–2000 (five jurisdictions) and 1996–2002 (five jurisdictions), were analyzed. Personnel were specifically trained to register, capture, and encode information. For each of these jurisdictions, the frequency, average annual age-standardized incidence (AAS) and average annual incidence per period by sex and, age, were calculated (rates per 1,000,000 children/years). RESULTS: In total 2,615 new cases of cancer were registered, with the male/female ratio generally >1, but in some tumors there were more cases in females (retinoblastoma, germ cells tumors). The principal groups of neoplasms in seven jurisdictions were leukemias, central nervous system tumors (CNS tumors), and lymphomas, and the combined frequency for these three groups was 62.6 to 77.2%. Most frequently found (five jurisdictions) was the North American-European pattern (leukemias-CNS tumors-lymphomas). Eight jurisdictions had AAS within the range reported in the world literature. The highest incidence was found for children underless than five year of age. In eight jurisdictions, leukemia had high incidence (>50). The AAS of lymphomas was between 1.9 to 28.6. Chiapas and Guerrero had the highest AAS of CNS tumors (31.9 and 30.3, respectively). The frequency and incidence of neuroblastoma was low. Chiapas had the highest incidence of retinoblastoma (21.8). Germ-cell tumors had high incidence. CONCLUSION: The North American-European pattern of cancers was the principal one found; the overall incidence was within the range reported worldwide. In general but particularly in two jurisdictions (Yucatán and Chiapas), it will be necessary to carry out studies concerning the causes of cancer in children. Due to the little that is known about the incidence of cancer in Mexican children, it will be necessary to develop a national program to establish a cancer registry for the whole of the country