Search results for "PC"
showing 10 items of 2805 documents
Soil chemical and biochemical properties of a salt-marsh alluvial Spanish area after long-term reclamation
2009
Marisma, one of the largest salt-marsh alluvial areas in SW Spain, has been reclaimed since 1970 by artificial drainage and amendment with phosphogypsum (PG) so as to reduce Na+ saturation. Within the reclaimed area, two 250- × 20-m plots were treated as follows: (1) amendment with 25 Mg/ha of PG every 2 to 3 years between 1979 and 2003 (plot PY); (2) like PY but PG treatment stopped after 1997 (plot DR). A contiguous virgin Marisma salt-marsh plot (MV), neither drained nor amended, was the control. In MV, soil microbial biomass C, most enzyme activities and total organic C content were much greater than in PY and DR soils, despite the salinity stress. The decrease in soil organic matter co…
Autoestima, percepción de estrés y ánimo depresivo en grupos de riesgo.
2001
Los grupos de riesgo se caracterizan por una mayor vulnerabilidad a desarrollar problemas psicológicos y sociales y, por tanto, suelen ser los destinatarios prioritarios de muchas de las intervenciones realizadas por los trabajadores sociales. En este sentido, en esta investigación se analizan tres variables psicológicas que pueden estar relacionadas con la mayor vulnerabilidad de los diversos grupos de riesgo- En concreto, se comparan las variables de autoestima, percepción de estrés y ánimo depresivo en personas que manifiestan un problema de salud física como es la hipertensión (n=30) y en personas con un problema de tipo psicosocial como es el consumo abusivo de alcohol (n=47) en relaci…
A tractor mounted scanning LIDAR for the non-destructive measurement of vegetative volume and surface area of tree-row plantations: A comparison with…
2009
The use of a low-cost tractor-mounted scanning Light Detection and Ranging (LIDAR) system for capable of making non-destructive recordings of tree-row structure in orchards and vineyards is described. Field tests consisted of several LIDAR measurements on both sides of the crop row, before and after defoliation of selected trees. Summary parameters describing the tree-row volume and the total crop surface area viewed by the LIDAR (expressed as a ratio with ground surface area) were derived using a suitable numerical algorithm. The results for apple and pear orchards and a wine producing vineyard were shown to be in reasonable agreement with the results derived from a destructive leaf sampli…
Sobre la recepción de Aretino en España a través de sus traducciones
2021
En primer lugar se pasa revista a los escasos estudios que se han ocupado de la recepción de Aretino en la literatura española. Tras ello, se analizan otras posibles vías de penetración de la obra de Aretino en España, como por ejemplo el contenido de los prólogos de algu- nas de las traducciones al castellano y al catalán hechas entre 1547 y 2000, o bien la selec- ción de textos traducidos. En tercer y último lugar, se estudia la calidad de todas las versiones localizadas. El trabajo se completa con un detallado catálogo de todas las traducciones de obras de Aretino publicadas hasta ahora en España, tanto en castellano como en catalán.Firstly there is a review of the rather few studies whi…
Initiator-Directed Transcription: Fission Yeast Nmtl Initiator Directs Preinitiation Complex Formation and Transcriptional Initiation
2022
The initiator element is a core promoter element encompassing the transcription start site, which is found in yeast, Drosophila, and human promoters. This element is observed in TATA-less promoters. Several studies have defined transcription factor requirements and additional cofactors that are needed for transcription initiation of initiator-containing promoters. However, those studies have been performed with additional core promoters in addition to the initiator. In this work, we have defined the pathway of preinitiation complex formation on the fission yeast nmt1 gene promoter, which contains a functional initiator with striking similarity to the initiator of the human dihydrofolate red…
Chromatin-dependent regulation of RNA polymerases II and III activity throughout the transcription cycle
2015
The particular behaviour of eukaryotic RNA polymerases along different gene regions and amongst distinct gene functional groups is not totally understood. To cast light onto the alternative active or backtracking states of RNA polymerase II, we have quantitatively mapped active RNA polymerases at a high resolution following a new biotin-based genomic run-on (BioGRO) technique. Compared with conventional profiling with chromatin immunoprecipitation, the analysis of the BioGRO profiles in Saccharomyces cerevisiae shows that RNA polymerase II has unique activity profiles at both gene ends, which are highly dependent on positioned nucleosomes. This is the first demonstration of the in vivo infl…
A complete set of nascent transcription rates for yeast genes
2010
The amount of mRNA in a cell is the result of two opposite reactions: transcription and mRNA degradation. These reactions are governed by kinetics laws, and the most regulated step for many genes is the transcription rate. The transcription rate, which is assumed to be exercised mainly at the RNA polymerase recruitment level, can be calculated using the RNA polymerase densities determined either by run-on or immunoprecipitation using specific antibodies. The yeast Saccharomyces cerevisiae is the ideal model organism to generate a complete set of nascent transcription rates that will prove useful for many gene regulation studies. By combining genomic data from both the GRO (Genomic Run-on) a…
Transcription of human neuronal nitric oxide synthase mRNAs derived from different first exons is partly controlled by exon 1-specific promoter seque…
2006
AbstractThe human neuronal nitric oxide synthase (NOS1) gene is subject to extensive splicing. A total of 12 NOS1 mRNA species have been identified. They differ in their 5′ ends and are derived from 12 different first exons (termed exons 1a to 1l). Various cell lines whose NOS1 first exon expression patterns were representative of human brain, skin, and skeletal muscle were identified. These included A673 neuroepithelioma cells, SK-N-MC neuroblastoma cells, HaCaT keratinocyte-like cells, and C2C12 myocyte-like cells. In these cell lines, correlations were found between the exon 1 variants preferentially expressed and the promoter activities of their cognate 5′ flanking sequences. These data…
Genomics of mRNA turnover
2007
Most studies on eukaryotic gene regulation have focused on mature mRNA levels. Nevertheless, the steady-state mRNA level is the result of two opposing biological processes: transcription and degradation, both of which can be important points to regulate gene expression. It is now possible to determine the transcription and degradation rates (TR and DR), as well as the mRNA amount, for each gene using DNA chip technologies. In this way, each individual contribution to gene expression can be analysed. This review will deal with the techniques used for the genomic evaluation of TR and DR developed for the yeast Saccharomyces cerevisiae. They will be described in detail and their potential draw…
A genomic view of mRNA turnover in yeast
2011
The steady-state mRNA level is the result of two opposing processes: transcription and degradation; both of which can provide important points to regulate gene expression. In the model organism yeast Saccharomyces cerevisiae, it is now possible to determine, at the genomic level, the transcription and degradation rates, as well as the mRNA amount, using DNA chip or parallel sequencing technologies. In this way, the contribution of both rates to individual and global gene expressions can be analysed. Here we review the techniques used for the genomic evaluation of the transcription and degradation rates developed for this yeast, and we discuss the integration of the data obtained to fully an…