775 research outputs found

    Mrub_2765 is the version of \u3cem\u3eE. coli\u3c/em\u3e FabZ in \u3cem\u3eMeiothermus ruber\u3c/em\u3e, while Mrub_0266 is the version of \u3cem\u3eE. coli\u3c/em\u3e FabI in \u3cem\u3eMeiothermus ruber\u3c/em\u3e

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    This project is part of the Meiothermus ruber genome analysis project, which uses the bioinformatics tools associated with the Guiding Education through Novel Investigation – Annotation Collaboration Toolkit (GENI-ACT) to predict gene function. We investigated the biological function of the genes Mrub_2765 and Mrub_0266. We predict that Mrub_2765 encodes the enzyme β-hydroxyacyl-Acyl carrier protein (ACP) dehydratase (DNA coordinates 2805770..2806213 on the reverse strand), which is the 3rd step of the fatty acid elongation pathway (KEGG map number 00780). It catalyzes the conversion of (3R)-3-hydroxyacyl-[ACP] to trans-2-enoyl-[ACP]. The E. coli K12 MG1655 ortholog is predicted to be b1080, which has the gene identifier FabZ. We also predict that Mrub_0266 encodes the enzyme enoyl-ACP reductase (DNA coordinates 232918..233712 on the reverse strand), which is the 4th step of the fatty acid elongation pathway (KEGG map number 00780). It catalyzes the conversion of trans-2-enoyl-[ACP] to acyl-ACP. The E. coli K12 MG1655 ortholog is predicted to be b1288, which has the gene identifier FabI

    Analysis of the impact of surface layer properties on evaporation from porous systems using column experiments and modified definition of characteristic length

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    The hydraulic properties of the layer at the vicinity of the soil surface have significant impact on evaporation, and could be harnessed to reduce water losses. The effect of the properties of the upper layer on the evolution of phase distribution during the evaporation process is first illustrated from three-dimensional pore network simulations. This effect is then studied from experiments carried out on soil columns under laboratory conditions. Comparisons between homogeneous columns packed with coarse (sand) and fine (sandy loam) materials, and heterogeneous columns packed with layers of fine overlying coarse material and coarse overlying fine material of different thicknesses are performed to assess the impact of upper layer properties on evaporation. Experiments are analyzed using the classical approach based on the numerical solution of Richards’s equation and semi-analytical theoretical predictions. The theoretical analysis is based on the clear distinction between two drying regimes, namely the capillary regime and the gravity-capillary regime, which are the prevailing regimes in our experiments. Simple relationships enabling to estimate the duration of stage-1 evaporation (S1) for both regimes are proposed. In particular, this led to defining the characteristic length for the gravity-capillary regime from the consideration of viscous effects at low water content differently from available expressions. The duration of S1, during which most of the water losses occur, for both the homogeneous and two-layer columns are presented and discussed. Finally, the impact of liquid films and it consequences on the soil hydraulic conductivity function are briefly discussed

    Development of wireless bruxism monitoring device based on pressure-sensitive polymer composite

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    A wireless pressure sensing bite guard has been developed for monitoring the progress of bruxism (teeth grinding during sleep); as well as protecting the teeth from damages. For sensing the pressure effectively in the restricted space and hostile environment, a pressure sensitive polymer composite has been fabricated and encapsulated into a conventional bite guard which is safe for in-situ applications. The device is anticipated to give real-time data through wireless data transmission and to have a long working life (weeks). A microcontroller-based electronic circuit has been built in-house for data collection and transmission. A low power approach is configured to increase the working life of the device. This device is a useful tool for understanding and treating bruxism

    One-class land-cover classification using MaxEnt: the effect of modelling parameterization on classification accuracy

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    Multiple-class land-cover classification approaches can be inefficient when the main goal is to classify only one or a few classes. Under this scenario one-class classification algorithms could be a more efficient alternative. Currently there are several algorithms that can fulfil this task, with MaxEnt being one of the most promising. However, there is scarce information regarding parametrization for performing land-cover classification using MaxEnt. In this study we aimed to understand how MaxEnt parameterization affects the classification accuracy of four different land-covers (i.e., built-up, irrigated grass, evergreen trees and deciduous trees) in the city of Santiago de Chile. We also evaluated if MaxEnt manual parameterization outperforms classification results obtained when using MaxEnt default parameters setting. To accomplish our objectives, we generated a set of 25,344 classification maps (i.e., 6,336 for each assessed land-cover), which are based on all the potential combination of 12 different classes of features restrictions, four regularization multipliers, four different sample sizes, three training/testing proportions, and 11 thresholds for generating the binary maps. Our results showed that with a good parameterization, MaxEnt can effectively classify different land covers with kappa values ranging from 0.68 for deciduous trees to 0.89 for irrigated grass. However, the accuracy of classification results is highly influenced by the type of land-cover being classified. Simpler models produced good classification outcomes for homogenous land-covers, but not for heterogeneous covers, where complex models provided better outcomes. In general, manual parameterization improves the accuracy of classification results, but this improvement will depend on the threshold used to generate the binary map. In fact, threshold selection showed to be the most relevant factor impacting the accuracy of the four land-cover classification. The number of sampling points for training the model also has a positive effect on classification results. However, this effect followed a logarithmic distribution, showing an improvement of kappa values when increasing the sampling from 40 to 60 points, but showing only a marginal effect if more than 60 sampling points are used. In light of these results, we suggest testing different parametrization and thresholds until satisfactory kappa or other accuracy metrics values are achieved. Our results highlight the huge potential that MaxEnt has a as a tool for one-class classification, but a good understanding of the software settings and model parameterization is needed to obtain reliable results

    Effect of large and small herbivores on seed and seedling survival of Beilschmiedia miersii in central Chile

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    SUMMARY In the Mediterranean region of Chile, populations of the threatened tree Beilschmiedia miersii have been strongly affected by anthropic disturbances, causing a critical state of conservation. Herbivory has been proposed as the main factor that currently limits the regeneration of this species. We studied the effect of large vs. small herbivores on seed and seedling survival of B. miersii under two contrasting habitat conditions (forest and shrubland), using plots with fenced enclosures which differentially excluded mammalian herbivores according to body size. Results show that herbivory had a significant negative effect on B. miersii. Both large and small herbivores had a significant negative effect on seeds and seedlings in the shrub habitat. In the forest habitat small herbivores had a significant negative effect only on seeds. Our results suggest that different herbivores can have varying effects on seed and seedling survival, but these effects can vary spatially, probably due to different herbivore assemblage of each habitat. Results suggest that restoration plans for B. miersii need to be adjusted according to local conditions. Key words: Beilschmiedia miersii, herbivory, seed predation, seedling survival, restoration. RESUMEN En la zona mediterránea de Chile, las poblaciones de la especie amenazada Beilschmiedia miersii han sido afectadas fuertemente por actividades antrópicas, provocando que actualmente se encuentre en un estado crítico de conservación. La herbivoría ha sido propuesta como el principal factor que limita actualmente la regeneración de esta especie. El efecto de herbívoros grandes versus pequeños, la etapa del ciclo de vida más afectada (semillas vs. plántulas) y si la sobrevivencia depende de las condiciones de hábitat permanece menos conocida. En este estudio evaluamos el efecto de diferentes tipos de herbívoros en la sobrevivencia de semillas y plántulas de B. miersii usando parcelas con cierres perimetrales que excluyeron a los herbívoros mamíferos de acuerdo a su tamaño. También evaluamos la variabilidad espacial del efecto de los herbívoros comparando entre habitas de matorral y bosque. Los resultados muestran que la herbivoría tuvo un efecto significativamente negativo sobre B. miersii. Ambos herbívoros, grandes y pequeños, tuvieron un efecto significativamente negativo sobre semillas y plántulas en el hábitat de matorral, donde la sobrevivencia de plántulas fue de 2,5% para exclusiones parciales y cero para parcelas sin exclusión. La sobrevivencia de semillas fue nula en las exclusiones parciales y en parcelas sin exclusión. En el hábitat de bosque los herbívoros pequeños tuvieron un efecto negativo solo sobre semillas. La sobrevivencia de semillas fue nula en parcelas parcialmente excluidas y parcelas sin exclusión. Nuestros resultados indican que diferentes tipos de herbívoros pueden tener efectos variados sobre semillas y plántulas, pero estos resultados pueden variar espacialmente, debido probablemente a los diferentes ensamblajes de herbívoros en cada hábitat. Los resultados sugieren que los planes de restauración de B. miersii deben ser ajustados de acuerdo al hábitat y al tipo de herbívoro. Palabras clave: Beilschmiedia miersii, herbivoría, depredación de semillas, sobrevivencia de plántulas, restauración

    Deficiency in the mRNA export mediator Gle1 impairs Schwann cell development in the zebrafish embryo

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    GLE1 mutations cause lethal congenital contracture syndrome 1 (LCCS1), a severe autosomal recessive fetal motor neuron disease, and more recently have been associated with amyotrophic lateral sclerosis (ALS). The gene encodes a highly conserved protein with an essential role in mRNA export. The mechanism linking Gle1 function to motor neuron degeneration in humans has not been elucidated, but increasing evidence implicates abnormal RNA processing as a key event in the pathogenesis of several motor neuron diseases. Homozygous gle1−/− mutant zebrafish display various aspects of LCCS, showing severe developmental abnormalities including motor neuron arborization defects and embryonic lethality. A previous gene expression study on spinal cord from LCCS fetuses indicated that oligodendrocyte dysfunction may be an important factor in LCCS. We therefore set out to investigate the development of myelinating glia in gle1−/− mutant zebrafish embryos. While expression of myelin basic protein (mbp) in hindbrain oligodendrocytes appeared relatively normal, our studies revealed a prominent defect in Schwann cell precursor proliferation and differentiation in the posterior lateral line nerve. Other genes mutated in LCCS have important roles in Schwann cell development, thereby suggesting that Schwann cell deficits may be a common factor in LCCS pathogenesis. These findings illustrate the potential importance of glial cells such as myelinating Schwann cells in motor neuron diseases linked to RNA processing defects
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