22 research outputs found

    Analyzing derived metallicities and ionization parameters from model-based determinations in ionized gaseous nebulae

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    We analyze the reliability of oxygen abundances and ionization parameters obtained from different diagnostic diagrams. For this, we compiled from the literature observational emission line intensities and oxygen abundance of 446 star-forming regions whose O/H abundance was determined by direct estimation of electron temperature. The abundances compiled were compared with the values calculated in this work using different diagnostic diagrams in combination with results from a grid of photoionization models. We found that the [\ion{O}{iii}]/[\ion{O}{ii}] vs. [\ion{N}{ii}]/[\ion{O}{ii}], [\ion{O}{iii}]/Hβ\beta vs. [\ion{N}{ii}]/[\ion{O}{ii}], and ([\ion{O}{iii}]/Hβ\beta)/([\ion{N}{ii}]/Hα\alpha) vs. [\ion{S}{ii}]/[\ion{S}{iii}] diagnostic diagrams give O/H values close to the TeT_{\rm e}-method, with differences of about 0.04 dex and dispersion of about 0.3 dex. Similar results were obtained by detailed models but with a dispersion of 0.08 dex. The origin of the dispersion found in the use of diagnostic diagrams is probably due to differences between the real N/O-O/H relation of the sample and the one assumed in the models. This is confirmed by the use of detailed models that do not have a fixed N/O-O/H relation. We found no correlation between ionization parameter and the metallicity for the objects of our sample. We conclude that the combination of two line ratio predicted by photoionization models, one sensitive to the metallicity and another sensitive to the ionization parameter, which takes into account the physical conditions of star-forming regions, gives O/H estimates close to the values derived using direct detections of electron temperatures.Comment: 12 pages, 9 figures, accepted by MNRA

    Post-glacial determinants of regional species pools in alpine grasslands

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    [Aim] Alpine habitats support unique biodiversity confined to high-elevation areas in the current interglacial. Plant diversity in these habitats may respond to area, environment, connectivity and isolation, yet these factors have been rarely evaluated in concert. Here we investigate major determinants of regional species pools in alpine grasslands, and the responses of their constituent species groups.[Location] European mountains below 50° N.[Time period] Between 1928 and 2019.[Major taxa studied] Vascular plants.[Methods] We compiled species pools from alpine grasslands in 23 regions, including 794 alpine species and 2,094 non-alpines. We used species–area relationships to test the influence of the extent of alpine areas on regional richness, and mixed-effects models to compare the effects of 12 spatial and environmental predictors. Variation in species composition was addressed by generalized dissimilarity models and by a coefficient of dispersal direction to assess historical links among regions.[Results] Pool sizes were partially explained by current alpine areas, but the other predictors largely contributed to regional differences. The number of alpine species was influenced by area, calcareous bedrock, topographic heterogeneity and regional isolation, while non-alpines responded better to connectivity and climate. Regional dissimilarity of alpine species was explained by isolation and precipitation, but non-alpines only responded to isolation. Past dispersal routes were correlated with latitude, with alpine species showing stronger connections among regions.[Main conclusions] Besides area effects, edaphic, topographic and spatio-temporal determinants are important to understand the organization of regional species pools in alpine habitats. The number of alpine species is especially linked to refugia and isolation, but their composition is explained by past dispersal and post-glacial environmental filtering, while non-alpines are generally influenced by regional floras. New research on the dynamics of alpine biodiversity should contextualize the determinants of regional species pools and the responses of species with different ecological profiles.The authors thank Daniela Gaspar for support in GIS analyses. B.J.-A. thanks the Marie Curie Clarín-COFUND program of the Principality of Asturias-EU (ACB17-26), the regional grant IDI/2018/000151, and the Spanish Research Agency grant AEI/ 10.13039/501100011033. J.V.R.-D. was supported by the ACA17-02FP7 Marie Curie COFUND-Clarín grant. G.P.M. was funded by US National Science Foundation award 1853665. C.M. was funded by grant no. 19-28491 of the Czech Science Foundation.Peer reviewe

    EUNIS Habitat Classification: Expert system, characteristic species combinations and distribution maps of European habitats

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    Aim: The EUNIS Habitat Classification is a widely used reference framework for European habitat types (habitats), but it lacks formal definitions of individual habitats that would enable their unequivocal identification. Our goal was to develop a tool for assigning vegetation‐plot records to the habitats of the EUNIS system, use it to classify a European vegetation‐plot database, and compile statistically‐derived characteristic species combinations and distribution maps for these habitats. Location: Europe. Methods: We developed the classification expert system EUNIS‐ESy, which contains definitions of individual EUNIS habitats based on their species composition and geographic location. Each habitat was formally defined as a formula in a computer language combining algebraic and set‐theoretic concepts with formal logical operators. We applied this expert system to classify 1,261,373 vegetation plots from the European Vegetation Archive (EVA) and other databases. Then we determined diagnostic, constant and dominant species for each habitat by calculating species‐to‐habitat fidelity and constancy (occurrence frequency) in the classified data set. Finally, we mapped the plot locations for each habitat. Results: Formal definitions were developed for 199 habitats at Level 3 of the EUNIS hierarchy, including 25 coastal, 18 wetland, 55 grassland, 43 shrubland, 46 forest and 12 man‐made habitats. The expert system classified 1,125,121 vegetation plots to these habitat groups and 73,188 to other habitats, while 63,064 plots remained unclassified or were classified to more than one habitat. Data on each habitat were summarized in factsheets containing habitat description, distribution map, corresponding syntaxa and characteristic species combination. Conclusions: EUNIS habitats were characterized for the first time in terms of their species composition and distribution, based on a classification of a European database of vegetation plots using the newly developed electronic expert system EUNIS‐ESy. The data provided and the expert system have considerable potential for future use in European nature conservation planning, monitoring and assessment

    Fortalecimiento para el desarrollo comercial de Distribuciones Amago S A S

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    Distribuciones Amago SAS, es una micro empresa Bogotana dedicada a la distribución de alimentos, en ella se evidenció que en el área comercial presentaba un represamiento de los inventarios, lo que afectaba las ventas. Esta situación llevó a que se desarrollara un plan de fortalecimiento organizacional en donde se implementaron estrategias comerciales para potenciar las ventas y lograr consolidar la relación con los clientes. Inicialmente se realizó una encuesta a los clientes actuales de la empresa para conocer su satisfacción con los productos y el servicio recibido, después de un análisis de resultados se identifican aspectos a mejorar, para lo cual desarrolló un plan de fortalecimiento con estrategias comerciales como la incursión en marketing digital: creación de página web, creación de perfiles en redes sociales, atención personalizada y acompañamiento a clientes con incentivos sobre sus compras, y en la parte interna se dio una organización al manejo de inventarios frente a la sistematización de formatos para el control de existencias y actualización de precios para hacer más efectivos los procesos en pedidos, garantizar disponibilidad para el cumplimiento a los clientes y prestar un servicio oportuno en las entregas y se determinó una tabla de incentivos para los vendedores. Las estrategias implementadas se orientan al logro de los objetivos organizacionales, especialmente al fortalecimiento económico, de modo que se presenta una proyección de ventas que evidencie que el plan propuesto impactará de forma positiva el crecimiento y la competitividad de la organización y su excelente desarrollo comercial para abrirse a nuevas oportunidades de mercados en el sector de abastecimiento de alimentosDistribuciones Amago SAS is a Bogotá microenterprise dedicated to the distribution of food, it was evidenced that in the commercial area there was a damming of inventories, which affected sales. This situation led to the development of an organizational strengthening plan where commercial strategies were implemented to boost sales and consolidate the relationship with customers. Initially, a survey was carried out to the current clients of the company to find out their satisfaction with the products and the service received, after an analysis of the results, aspects to improve are identified, for which it developed a strengthening plan with commercial strategies such as the incursion in digital marketing: website creation, creation of profiles in social networks, personalized attention and support to clients with incentives on their purchases, and in the internal part an organization was given to the management of inventories compared to the systematization of formats for control of stocks and price updates to make ordering processes more effective, guarantee availability for fulfillment to customers and provide timely service in deliveries and a table of incentives for sellers was determined. The implemented strategies are aimed at achieving organizational objectives, especially economic strengthening so that a sales projection is presented that shows that the proposed plan will positively impact the growth and competitiveness of the organization and its excellent commercial development for open up to new market opportunities in the food supply sector.Agradecimientos. -- Resumen. -- Introducción. -- Justificación. -- Planteamiento del Problema. -- Objetivo General. -- Objetivos Específicos. -- Marco Teórico. -- Caracterización de la Compañía. -- Misión. -- Visión. -- Productos. -- Áreas. -- Instrumentos de Recolección de Información. -- Diagnóstico Organizacional. -- Plan de Fortalecimiento. -- Desarrollo del plan de acción. -- Conclusiones. -- Referencias. -

    Molecular characterization of intrinsic and acquired antibiotic resistance in lactic acid bacteria and bifidobacteria

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    The minimum inhibitory concentrations (MICs) of 6 different antibiotics (chloramphenicol, clindamycin, erythromycin, streptomycin, tetracycline and vancomycin) were determined for 143 strains of lactic acid bacteria and bifidobacteria using the Etest. Different MICs were found for different species and strains. Based on the distribution of these MIC values, most of the strains were either susceptible or intrinsically resistant to these antibiotics. However, the MIC range of some of these antibiotics showed a bimodal distribution, which suggested that some of the tested strains possess acquired antibiotic resistance. Screening for resistance genes was performed by PCR using specific primers, or using a DNA microarray with around 300 nucleotide probes representing 7 classes of antibiotic resistance genes. The genes identified encoded resistance to tetracycline [tet(M), tet(W), tet(O) and tet(O/W)], erythromycin and clindamycin [erm(B)] and streptomycin [aph(E) and sat(3)]. Internal portions of some of these determinants were sequenced and found to be identical to genes described in other bacteria. All resistance determinants were located on the bacterial chromosome, except for tet(M), which was identified on plasmids in Lactococcus lactis. The contribution of intrinsic multidrug transporters to the antibiotic resistance was investigated by cloning and measuring the expression of Bifidobacterium breve genes in L. lactis.Work on antibiotic resistance in LAB&B strains at the authors' laboratories was supported by an EU project within the sixth Framework Programme (ref. 506214). M.S.A. was awarded a postdoctoral fellowship from the Secretaria de Estado de Universidades e Investigación of the Spanish Ministry of Education and Science (ref. SB2004-0165).Peer reviewe

    Coenzyme Q is irreplaceable by demethoxy-coenzyme Q in plasma membrane of Caenorhabditis elegans

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    7 páginas, 5 figuras, 2 tablas.A procedure was developed to isolate fractions enriched in plasma membrane from Caenorhabditis elegans. Coenzyme Q9 (Q9) was found in plasma membrane isolated from either wild-type or long-lived qm30 and qm51 clk-1 mutant strains of Caenorhabditis elegans, along with dietary coenzyme Q8 (Q8) and the biosynthetic intermediate demethoxy-Q9 (DMQ9). NADH was able to reduce both Q8 and Q9, but not DMQ9. Our results indicate that DMQ9 cannot achieve the same redox role of Q9 in plasma membrane, suggesting that proportion of all these Q isoforms in plasma membrane must be an important factor in establishing the clk-1 mutant phenotype.This work has been supported by the Spanish Ministerio de Ciencia y Tecnología, Grant BFU2005-03017/BMC. A.A. was supported by the Junta de Andalucía “Programa de Incorporación de Doctores a Centros de Investigación Andaluces”. A.G. was supported by The 6th Framework Programme – STREP/LSHB-CT-2004-005151.Peer reviewe

    Differential expression pattern of coq-8 gene during development in Caenorhabditis elegans

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    Coenzyme Q (Q) and the genes involved in its biosynthesis are involved in aging and development of Caenorhabditis elegans. Q is synthesized by at least eight highly conserved nuclear coq genes, but this biosynthesis pathway and its regulation is not known. The coq-8 gene sequence has homology to the ABC-1 family kinases and is the only known candidate for a possible regulation of this pathway. To study coq-8 expression pattern, we have developed a C. elegans transgenic strain expressing ubiquinone biosynthesis coq-8 gene promoter and GFP construct. We show here an age-dependent specific pattern from embryo to senescence for COQ-8 protein expression. Expression in embryo was triggered by a defined group of blastomers before morphogenesis. In elderly nematodes expression was only observed in nervous system, whilst expression in larvae was also detected in hypodermis, muscles and coelomocytes. Global expression provide a regulated pattern during life cycle of the nematode.This work has been partially supported by Spanish Dirección General de Educación Superior grant BMC-2002-01602

    Severe encephalopathy associated to pyruvate dehydrogenase mutations and unbalanced coenzyme Q10 content

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    et al.Coenzyme Q10 (CoQ10) deficiency is associated to a variety of clinical phenotypes including neuromuscular and nephrotic disorders. We report two unrelated boys presenting encephalopathy, ataxia, and lactic acidosis, who died with necrotic lesions in different areas of brain. Levels of CoQ10 and complex II+III activity were increased in both skeletal muscle and fibroblasts, but it was a consequence of higher mitochondria mass measured as citrate synthase. In fibroblasts, oxygen consumption was also increased, whereas steady state ATP levels were decreased. Antioxidant enzymes such as NQO1 and MnSOD and mitochondrial marker VDAC were overexpressed. Mitochondria recycling markers Fis1 and mitofusin, and mtDNA regulatory Tfam were reduced. Exome sequencing showed mutations in PDHA1 in the first patient and in PDHB in the second. These genes encode subunits of pyruvate dehydrogenase complex (PDH) that could explain the compensatory increase of CoQ 10 and a defect of mitochondrial homeostasis. These two cases describe, for the first time, a mitochondrial disease caused by PDH defects associated with unbalanced of both CoQ10 content and mitochondria homeostasis, which severely affects the brain. Both CoQ10 and mitochondria homeostasis appears as new markers for PDH associated mitochondrial disorders.This research was funded by grants PI14/00028 (RA), PI10-00662 (JM), and PI14/01962 (PN) from the Spanish Ministry of Health (Fondo de Investigación Sanitaria, Instituto de Salud Carlos III). LS was funded by Telethon Italy (GGP13222), the University of Padova (CPDA123573/12), and Fondazione CARIPARO (to LS). CA was funded by grant APP2D11086 from the University Pablo de Olavide (Plan Propio de Investigación).Peer Reviewe

    Post-glacial determinants of regional species pools in alpine grasslands

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    Aim Alpine habitats support unique biodiversity confined to high-elevation areas in the current interglacial. Plant diversity in these habitats may respond to area, environment, connectivity and isolation, yet these factors have been rarely evaluated in concert. Here we investigate major determinants of regional species pools in alpine grasslands, and the responses of their constituent species groups. Location European mountains below 50 degrees N. Time period Between 1928 and 2019. Major taxa studied Vascular plants. Methods We compiled species pools from alpine grasslands in 23 regions, including 794 alpine species and 2,094 non-alpines. We used species-area relationships to test the influence of the extent of alpine areas on regional richness, and mixed-effects models to compare the effects of 12 spatial and environmental predictors. Variation in species composition was addressed by generalized dissimilarity models and by a coefficient of dispersal direction to assess historical links among regions. Results Pool sizes were partially explained by current alpine areas, but the other predictors largely contributed to regional differences. The number of alpine species was influenced by area, calcareous bedrock, topographic heterogeneity and regional isolation, while non-alpines responded better to connectivity and climate. Regional dissimilarity of alpine species was explained by isolation and precipitation, but non-alpines only responded to isolation. Past dispersal routes were correlated with latitude, with alpine species showing stronger connections among regions. Main conclusions Besides area effects, edaphic, topographic and spatio-temporal determinants are important to understand the organization of regional species pools in alpine habitats. The number of alpine species is especially linked to refugia and isolation, but their composition is explained by past dispersal and post-glacial environmental filtering, while non-alpines are generally influenced by regional floras. New research on the dynamics of alpine biodiversity should contextualize the determinants of regional species pools and the responses of species with different ecological profiles.Gobierno del Principado de AsturiasAgencia Nacional de Investigación e InnovaciónFundación para el Fomento en Asturias de la Investigación Científica Aplicada y la TecnologíaPrograma Clarín COFUNDDepto. de Farmacología, Farmacognosia y BotánicaFac. de FarmaciaTRUEpu

    Molecular clues to understand the aerotolerance phenotype of Bifidobacterium animalis subsp. lactis

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    Oxygen is one of the abiotic factors negatively affecting the survival of Bifidobacterium strains used as probiotics, mainly due to the induction of lethal oxidative damage. Aerobic conditions are present during the process of manufacture and storage of functional foods, and aerotolerance is a desired trait for bifidobacteria intended for use in industry. In the present study, the molecular response of Bifidobacterium animalis subsp. lactis IPLA4549 to aerobic conditions is presented. Molecular targets affected by oxygen were studied using two-dimensional electrophoresis (2DE) and quantitative reverse transcriptase (qRT) PCR. Globally, oxygen stress induced a shift in the glycolytic pathway toward the production of acetic acid with a concomitant increase in ATP formation. Several changes in the expression of genes coding for enzymes involved in redox reactions were detected, although the redox ratio remained unaltered. Interestingly, cells grown under aerobic conditions were characterized by higher activity of coproporphyrinogen III oxidase, which can directly detoxify molecular oxygen, and by higher NADH oxidase specific activity, which can oxidize NADH using hydrogen peroxide. In turn, this is in agreement with the glycolytic shift toward acetate production, in that more NADH molecules may be available due to the lower level of lactic acid formation. These findings further our ability to elucidate the mechanisms by which B. animalis copes with an oxygen-containing atmosphere. © 2012, American Society for Microbiology.Peer Reviewe
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