572 research outputs found

    Tamoxifen- and Mifepristone-Inducible Versions of CRISPR Effectors, Cas9 and Cpf1

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    Methods for making specific modifications to the genomes of living cells are powerful research tools. Two methods currently dominate, CRISPR and Cre recombinase. CRISPR has the advantage that it can act on unmodified target genes; Cre has the advantage of being available in drug-inducible versions, allowing temporal control, but it requires engineering (“floxing”) of the target gene. Here, we have combined these advantages by constructing drug (tamoxifen/mifepristone)-inducible Cas9 and Cpf1 CRISPR effectors. We demonstrate their low background activity and robust activation with drugs, by using gRNAs to target them to TetR, in a cell carrying a Tet-repressed reporter gene. As well as being useful in their own right, the research tools generated here will pave the way to making further drug-inducible effector proteins

    Dos nuevas especies y una subespecie de campodeidos cavernícolas de la cornisa cantábrica (Diplura, Campodeidae)

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    A total of 139 specimens of campodeid diplurans, collected from 27 caves of Cantabrian Cornice (Spain) are studied and two new species and one subspecies are described: Podocampa asturiana n. sp., Podocampa asturiana riberiensis n. ssp. and Litocampa zaldivarae n. sp. P. asturiana n. sp. differs from its most closely related species, P. group fragiloides (an endogean species) by troglomorphic characters; P. asturiana riberiensis n. ssp. is distinct from the type species by the number of trochanteral bacilliform sensilla; and L. zaldivarae n. sp. is easely recognized from Litocampa espanoli by the number of macrochaetae posterior lateral in IV urotergite. These new discoveries show the value and diversity of this family of apterygote insects in the Cantabrian subterranean environment.Se han estudiado un total de 139 ejemplares de zipluros campodeidos, recolectados en 27 grutas de la cornisa cantábrica y se han descrito dos nuevas especies y una subespecie: Podocampa asturiana sp. n., Podocampa asturiana riberiensis ssp. n. y Litocampa zaldivarae sp. n. P. asturiana sp. n. difiere de la especie más próxima, Podocampa grupo fragiloides (una forma de hábitat endógeo), por características relacionadas con su facies cavernícola; P. asturiana riberiensis ssp. n. difiere de la especie tipo por el número de sensilos baciliformes trocanterales; y L. zaldivarae sp. n. es fácilmente distinguible de Litocampa espanoli por el número de macroquetas laterales posteriores del IV uroterguito. Estos nuevos hallazgos indican la riqueza y diversidad de esta familia de insectos apterigotos en el medio subterráneo cantábrico

    The Social Balance Sheet as Part of the Annual Report in Financial Institutions. A Case Study: Banco Bilbao Vizcaya Argentaria (BBVA).

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    In this paper, we examine the concept of the social balance sheet (SBS) and its evolution in corporate social reports that large companies have to issue today in their yearly statements. The SBS allows companies to evaluate their compliance with corporate social responsibility during a specific period and quantify its level of accomplishment. From a methodological perspective, this research analyzed the information that should be contained in the SBS report comparing economic value added (EVA) with other social value added statements (SVA), analyzing also in detail the case of Spain’s Banco Bilbao Vizcaya Argentaria (BBVA) bank as one of the pioneers in offering social reports. Along with this study, their metrics following EVA were recalculated and a more academic SVA statement was proposed for this specific case.post-print992 K

    Road accidents in Spain: Are they persistent?

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    Traffic accidents involve great costs both at an economic and a human level. This demands that governments implement strategies to reduce their number and impact. The knowledge of the nature of the phenomenon through the study of time series of accidents enables the design of suitable policies for the desired objectives to be achieved. Thus, this paper deals with the analysis of the statistical properties of the number of road accidents on Spanish roads by using time series techniques based on the concept of fractional integration. The results indicate that the series examined display very low degrees of persistence, with the orders of integration being around 0 and thus showing a short memory pattern. This implies that shocks will be transitory, disappearing fast, and requiring strong policy measures in the case of positive shocks that reduce the number of deaths if we want to maintain that effect in the long run.pre-print1174 K

    Overcoming biochar limitations to remediate pentachlorophenol in soil by modifying its electrochemical properties

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    In this study, we produced modified biochars with enhanced electrochemical properties to increase PCP remediation in soil. Although all biochars enhanced PCP remediation in aerobic conditions, only a few did in anaerobic soil. The most successful modifications were (i) the preloading of biomass with 10% w/w FeCl3, to obtain a biochar rich in redox-active metals (B-Fe); (ii) the oxidation of a conductive biochar pyrolyzed at 1000 ºC with 0.025 M KMnO4, to produce a biochar with both moderate conductivity and redox capacity (B-1000-KMnO4); and (iii) KMnO4 oxidation of an amorphous biochar pyrolyzed at 400 ºC to obtain a biochar with very high redox capacity (B-KMnO4). B-Fe reduced extractable PCP to almost zero after 50 days in both incubations, but showed slow kinetics of remediation in aerobic soil. B-1000-KMnO4 had the highest rate of remediation under aerobic conditions, but no significant effect under anaerobic conditions. B-KMnO4, however, presented high rates of remediation and high removal of extractable PCP under both conditions, which made it the recommended modification strategy for increased PCP remediation. We found that the degree of remediation primarily depends on the redox capacity, while the rate of remediation was determined by both the conductivity and redox capacity of biochar

    The complexity of soil biological sustainability

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    Additions of organic amendments to soil not only compensate for decreased soil C, but also contribute to energy requirements for conserving biological activity levels. The soil microbial biomass displays some highly conserved, and possibly unique, characteristics that do not permit a classic interpretation of microbial metabolic parameter data. The resilience of soil microbial biomass and the role of soil organic matter in sustaining microbial biomass under practically zero C inputs were assessed in two long term incubation experiments using soils from the Broadbalk experiment at Rothamsted (UK). Soils with low organic C contents, showed the greatest decline in biomass C during the first 30 d of incubation. The ATP concentration of this rapidly declining microbial biomass did not change during the prolonged incubation period, confirming this peculiar character of the soil microbial biomass. Specific respiration rate did not depend upon substrate availability, being higher in soils that had received the lowest C inputs. Qualitative and quantitative changes observed in humic fractions suggest that humified soil organic matter is a much more dynamic soil fraction than is normally considered and provides a utilizable energy reserve for soil microorganisms. Carbon levels can be successfully restored in soils through practices such as incorporation of crop residues, re\u2010vegetation and application of manures, biosolids and composts. Some amendments, such as olive mill waste compost, promote incorporation of altered lignin structures, N\u2010containing compounds and carbohydrates into humic acids. The mineral\u2010bound fraction of humic C also increases, after their addition, and contributes to the accumulation of the most inert soil C pools

    Almost Perfect Privacy for Additive Gaussian Privacy Filters

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    We study the maximal mutual information about a random variable YY (representing non-private information) displayed through an additive Gaussian channel when guaranteeing that only ϵ\epsilon bits of information is leaked about a random variable XX (representing private information) that is correlated with YY. Denoting this quantity by gϵ(X,Y)g_\epsilon(X,Y), we show that for perfect privacy, i.e., ϵ=0\epsilon=0, one has g0(X,Y)=0g_0(X,Y)=0 for any pair of absolutely continuous random variables (X,Y)(X,Y) and then derive a second-order approximation for gϵ(X,Y)g_\epsilon(X,Y) for small ϵ\epsilon. This approximation is shown to be related to the strong data processing inequality for mutual information under suitable conditions on the joint distribution PXYP_{XY}. Next, motivated by an operational interpretation of data privacy, we formulate the privacy-utility tradeoff in the same setup using estimation-theoretic quantities and obtain explicit bounds for this tradeoff when ϵ\epsilon is sufficiently small using the approximation formula derived for gϵ(X,Y)g_\epsilon(X,Y).Comment: 20 pages. To appear in Springer-Verla

    Ordinal regression methods: survey and experimental study

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    Abstract—Ordinal regression problems are those machine learning problems where the objective is to classify patterns using a categorical scale which shows a natural order between the labels. Many real-world applications present this labelling structure and that has increased the number of methods and algorithms developed over the last years in this field. Although ordinal regression can be faced using standard nominal classification techniques, there are several algorithms which can specifically benefit from the ordering information. Therefore, this paper is aimed at reviewing the state of the art on these techniques and proposing a taxonomy based on how the models are constructed to take the order into account. Furthermore, a thorough experimental study is proposed to check if the use of the order information improves the performance of the models obtained, considering some of the approaches within the taxonomy. The results confirm that ordering information benefits ordinal models improving their accuracy and the closeness of the predictions to actual targets in the ordinal scal

    Effects of nitrate contamination and seasonal variation on the denitrification and greenhouse gas production in La Rocina stream (Doñana National Park, SW Spain)

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    Climatic influence (global warming and decreased rainfall) could lead to an increase in the ecological and toxicological effects of the pollution in aquatic ecosystems, especially contamination from agricultural nitrate (NO3 −) fertilizers. Physicochemical properties of the surface waters and sediments of four selected sites varying in NO3 − concentration along La Rocina Stream, which feeds Marisma del Rocio in Do˜nana National Park (South West, Spain), were studied. Electrical conductivity, pH, content in macro and microelements, total organic carbon and nitrogen, and dissolved carbon and nitrogen were affected by each sampling site and sampling time. Contaminant NO3 − in surface water at the site with the highest NO3 − concentration (ranged in 61.6–106.6mgL−1) was of inorganic origin, most probably from chemical fertilizers, as determined chemically (90% of the total dissolved nitrogen from NO3 −) and by isotopic analysis of ı15N-NO3 −. Changes in seasonal weather conditions and hydrological effects at the sampling sites were also responsible for variations in some biological activities (dehydrogenase, -glucosidase, arylsulphatase, acid phosphatase and urease) in sediments, as well as in the production of the greenhouse gases CO2, CH4 and N2O. Both organic matter and NO3 − contents influenced rates of gas production. Increased NO3 − concentration also resulted in enhanced levels of potential denitrification measured as N2O production. The denitrification process was affected by NO3 − contamination and the rainfall regimen, increasing the greenhouse gases emissions (CO2, CH4 and especially N2O) during the driest season in all sampling sites studied.This work was supported by grants CGL2006-06870 and CTM2009-1473-C02-02 from Ministerio de Ciencia e Innovación (Spain) and RNM-4746 from Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía (Spain), all of them co-financed by the European Regional Development Fund (ERDF). Support of Junta de Andalucía to Research Group BIO-275 is also acknowledged. D. David Correa thanks Ministerio de Educación for predoctoral grant AP2007-03967.Peer reviewe
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