Species-Specific Effects of Epigeic Earthworms on Microbial Community Structure during First Stages of Decomposition of Organic Matter

Background: Epigeic earthworms are key organisms in organic matter decomposition because of the interactions they establish with microorganisms. The earthworm species and the quality and/or substrate availability are expected to be major factors influencing the outcome of these interactions. Here we tested whether and to what extent the epigeic earthworms Eisenia andrei, Eisenia fetida and Perionyx excavatus, widely used in vermicomposting, are capable of altering the microbiological properties of fresh organic matter in the short-term. We also questioned if the earthworm-induced modifications to the microbial communities are dependent on the type of substrate ingested. Methodology/Principal Findings: To address these questions we determined the microbial community structure (phospholipid fatty acid profiles) and microbial activity (basal respiration and microbial growth rates) of three types of animal manure (cow, horse and rabbit) that differed in microbial composition, after being processed by each species of earthworm for one month. No differences were found between earthworm-worked samples with regards to microbial community structure, irrespective of type of manure, which suggests the existence of a bottleneck effect of worm digestion on microbial populations of the original material consumed. Moreover, in mesocosms containing cow manure the presence of E. andrei resulted not only in a decrease in bacterial and fungal biomass, but also in a reduced bacterial growth rate and total microbial activity, while no such reduction was found with E. fetida and P. excavatus

Analysis of the stress state of a halved and tabled traditional timber scarf joint with the Finite Element Method

The purpose of this study is to determine the stress distribution in the carpentry joint of halved and tabled scarf joint with the finite element method (FEM) and its comparison with the values obtained using the theory of Strength of Materials. The stress concentration areas where analyzed and the influence of mesh refinement was studied on the results in order to determine the mesh size that provides the stress values more consistent with the theory. In areas where stress concentration is lower, different mesh sizes show similar stress values. In areas where stress concentration occurs, the same values increase considerably with the refinement of the mesh. The results show a central symmetry of the isobar lines distribution where the centre of symmetry corresponds to the geometric centre of the joint. Comparison of normal stress levels obtained by the FEM and the classical theory shows small differences, except at points of stress concentration

Relationship between peat formatíon and holocene environmental conditions in Sierra do Bocelo (NW Spain)

[Resumen] Se estudian las condiciones de formación y evolución de una serie de depósitos de turba de la Sierra de O Bocelo (A Coruña) y se relacionan con su morfología. La primera etapa formadora de turberas parte de finales del Atlántico, según han puesto de manifiesto las dataciones raciocarbónicas y las características polínicas de los perfiles estudiados; su origen se asocia con el incremento de precipitaciones de la época y con su situación topográfica. A principios del Subatlántico tuvo lugar una segunda fase de formación de turberas, que se relaciona con la degradación de las masas forestales por la acción del hombre y posiblemente con una degradación climática. El grado de descomposición de la wrba estimado por el sistema de Von Post refleja los distintos ciclos evolutivos de estas turberas.[Abstract] The conditions of the formation and evolution of a series of peats in Sierra do Bocelo (A Coruña, Spain) were studied and related to their morphology. Carbon dating and pollen characteristics show an initial peat-forming period beginning in the late Atlantic in topographically suitable areas due to increased rainfall. A second peat-formation period in the early Sub-Atlantic relates to increasing deforestation due to man, and possibly to worsening climate also. The successive cycles undergone by these peats are reflected by their degree of decomposition as measured on Von Post' s scale

AEROMICOTA DE AMBIENTES INTERNOS: COMPARACION DE METODOS DE MUESTREO

El procedimiento de muestreo utilizado paradeterminar el grado de contaminación fúngica enambientes internos, difiere según los autores. Por ello,con el fin de conocer si el método utilizado por nuestrogrupo de investigación, es comparable con otrasmetodologías, se ha realizado un estudio comparativocon varios sistemas de captación de esporas del aire,incluyendo equipos volumétricos (Aeroscope Chirana,System Air Sampler, Burkard Personal Culture) así comoel método tradicional por sedimentación. Los resultadosobtenidos muestran que apenas existen diferenciascuando se utilizan los sistemas volumétricos, sinembargo, el método por sedimentación ha sido menoseficaz, tanto desde el punto de vista cuantitativo comocualitativo. Mientras, el método directo por hisopado,resulta un buen complemento para determinar la fuentede contaminación. También se ha determinado la horadel día con mayor carga fúngica, que se localiza almediodía y tras el análisis de varios medios de cultivo,se concluye que el Agar Glucosa de Sabouraud resultaadecuado para este tipo de investigaciones

Diversity, structure and sources of bacterial communities in earthworm cocoons.

Animals start interactions with the bacteria that will constitute their microbiomes at embryonic stage. After mating, earthworms produce cocoons externally which will be colonized with bacteria from their parents and the environment. Due to the key role bacterial symbionts play on earthworm fitness, it is important to study bacterial colonization during cocoon formation. Here we describe the cocoon microbiome of the earthworms Eisenia andrei and E. fetida, which included 275 and 176 bacterial species, respectively. They were dominated by three vertically-transmitted symbionts, Microbacteriaceae, Verminephrobacter and Ca. Nephrothrix, which accounted for 88% and 66% of the sequences respectively. Verminephrobacter and Ca. Nephrothrix showed a high rate of sequence variation, suggesting that they could be biparentally acquired during mating. The other bacterial species inhabiting the cocoons came from the bedding, where they accounted for a small fraction of the diversity (27% and 7% of bacterial species for E. andrei and E. fetida bedding). Hence, earthworm cocoon microbiome includes a large fraction of the vertically-transmitted symbionts and a minor fraction, but more diverse, horizontally and non-randomly acquired from the environment. These data suggest that horizontally-transmitted bacteria to cocoons may play an important role in the adaptation of earthworms to new environments or diets

Physical and sexual violence, childhood sexual abuse and HIV/STI risk behaviour among alcohol-using women engaged in sex work in Mongolia

Although the prevalence of human immunodeficiency virus (HIV) in Mongolia is low, it could increase without strategic prevention strategies. Female sex workers (FSWs) often experience barriers to prevention, including interpersonal violence. This study investigated if childhood sexual abuse (CSA) or recent physical or sexual violence was associated with HIV sexual risk behaviours and if CSA modified associations between recent violence and HIV sexual risk behaviours. Two-hundred twenty-two women who (1) were at least 18 years old and clients at the National AIDS Foundation; (2) reported vaginal or anal sex in the past 90 days in exchange for money or goods and (3) met criteria for harmful alcohol use in the past year were enrolled. In-person interviews assessed sexual risk behaviours and violence in childhood and adulthood. Negative binomial regression, ordinary least squares regression and modified Poisson regression were performed. Sexual risk with paying partners was associated with penetrative CSA and sexual violence by paying partners. CSA and recent violence were not associated with sexual risk behaviours with intimate partners. CSA modified the association between recent sexual violence and unprotected sex with intimate partners. Findings highlight the need for integrated violence and sexual risk reduction services to ensure safe and effective prevention for FSWs

El polen de Poaceae en la atmósfera de Lugo y su relación con los parámetros meteorológicos (1999-2001).

RESUMEN. El polen de Poaceae en la atmósfera de Lugo y su relación con los parámetros meteorológicos (1999-2001). Se han estudiado las concentraciones de polen de Poaceae presente en la atmósfera de la ciudad de Lugo durante 3 años (1999-2001). Para ello se ha utilizado un captador volumétrico tipo Hirst, modelo Lanzoni VPPS-2000. El polen de Poaceae es el más abundante y su porcentaje frente al total de polen anual es de un 38-40%. La cantidad total de polen anual es de 8.400 granos como resultado de la media de los tres años de estudio, con un período de polinización durante los meses de Junio y Julio. A lo largo del día los máximos de concentración tienen lugar durante la tarde. Se ha realizado un análisis de correlación con los principales parámetros meteorológicos, siendo la temperatura máxima la variable que presentó el coeficiente más elevado. La suma acumulada de la temperatura máxima y la regresión múltiple integrando la temperatura máxima y las concentraciones de polen del día anterior como estimadores, resultaron métodos válidos y complementarios para realizar la predicción del inicio del periodo de polinización y de las concentraciones medias diarias que se alcanzan durante el periodo de polinización principal respectivamente.Palabras clave. Polen, Lugo, Meteorología, Predicción, lntradiario, Poaceae.ABSTRACT. The Poaceae pollen in the atmosphere of Lugo and its relationship with meteorological parameters ( 1999-2001). The pollen concentrations of Poaceae in the atmosphere of the city of Lugo has been studied during 3 years (1999-2001). A volumetric sampler type Hirst, model Lanzoni VPPS-2000 has been used. The Poaceae pollen is the most abundant and its percentage with respect to the total annual pollen ranged from 38-40 %. The annual total quantity of pollen of Poaceae were 8.400 grains as average of the three years studied, with a period of pollination during the months of June and July. The daily maximum concentrations take place during the evening. An analysis of correlation has been carried out between pollen concentrations and the main meteorological parameters, the maximum temperature being the variable that presented the highest coefficient value. The sum of maximum temperatures and the multiple regression integrating maximum temperature and pollen concentrations of the previous day as predictors, were successful and complementary methods in order to predict the beginning of the pollination period and the daily mean concentrations reached during the main pollen season respectively.Key words. Pollen, Lugo, Meteorology, Prediction, Intradiurnal, Poaceae