933 research outputs found

    Disulfide Engineered Lipase to Enhance the Catalytic Activity: A Structure-Based Approach on BTL2

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    Enhancement, control, and tuning of hydrolytic activity and specificity of lipases are major goals for the industry. Thermoalkaliphilic lipases from the I.5 family, with their native advantages such as high thermostability and tolerance to alkaline pHs, are a target for biotechnological applications. Although several strategies have been applied to increase lipases activity, the enhancement through protein engineering without compromising other capabilities is still elusive. Lipases from the I.5 family suffer a unique and delicate double lid restructuration to transition from a closed and inactive state to their open and enzymatically active conformation. In order to increase the activity of the wild type Geobacillus thermocatenulatus lipase 2 (BTL2) we rationally designed, based on its tridimensional structure, a mutant (ccBTL2) capable of forming a disulfide bond to lock the open state. ccBTL2 was generated replacing A191 and F206 to cysteine residues while both wild type C64 and C295 were mutated to serine. A covalently immobilized ccBTL2 showed a 3.5-fold increment in esterase activity with 0.1% Triton X-100 (2336 IU mg-1) and up to 6.0-fold higher with 0.01% CTAB (778 IU mg-1), both in the presence of oxidizing sulfhydryl agents, when compared to BTL2. The remarkable and industrially desired features of BTL2 such as optimal alkaliphilic pH and high thermal stability were not affected. The designed disulfide bond also conferred reversibility to the enhancement, as the increment on activity observed for ccBTL2 was controlled by redox pretreatments. MD simulations suggested that the most stable conformation for ccBTL2 (with the disulfide bond formed) was, as we predicted, similar to the open and active conformation of this lipase.Financial and logistic support from Colombian Universidad del Valle and COLCIENCIAS (CI 71083-Grant 745-2016-Project 110671250425), Spanish CICYT project BIO-2005-6018576, BFU2017-90030-P, and BFU2011-25326, B. Di G. In addition, thanks to the Spanish MINECO for a FPU fellowship.S

    Mujeres: familia, redes de poder y finanzas en la primera modernización de una ciudad fabril. Orizaba (1870–1920)

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    57 p.El presente artículo es una propuesta de historia social de la economía en el que se analiza las dinámicas económicas y financieras de las mujeres en la región de Orizaba entre los años de 1870 y 1920. En un primer apartado se presenta un encuadre en el que se identifican algunas hipótesis sobre el estudio de mujeres y sus relaciones sociales y económicas. En un segundo momento se realiza un acercamiento estadístico de la participación económica de la población en la segunda mitad del siglo XIX. Finalmente se identifican las interacciones familiares y políticas de las mujeres en el desarrollo de los mercados de dinero, de capital, financieros e inmobiliarios que posibilitaron la tecnificación de las actividades industriales y de comunicación durante el porfiriato en la región de Orizaba.The following paper is a review of socioeconomic history in which the economic and financial dynamics of women in the Orizaba region between the year 1870 and 1920 are analyzed. The first section proposes a framework in which hypotheses about the study of relationships between women and their social and economic situations are identified. In the second section a statistical analysis of the economic participation of the population in the second half of the 19th century is presented. In the last part, the influence of political and family values of women on the development of financial and real estate markets and the resulting modernization of industry and communication during the era of Porfirio Díaz are explored

    For a social history of the economy

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    61 p.El presente artículo responde a una impronta académica en la que se auto reflexiona sobre postura teórico-metodológica para la representación del pasado. En él se presenta un diálogo sobre la trayectoria de la profesionalización de la historia en Veracruz. En una segunda parte se expone la condición de la historia y en la tercera se realiza una propuesta de la historia social de la economía cuyo nodo está centrado en el dinero, como una expresión abstracta de las interacciones existentes entre las realidades mercantiles, financieras y sociales de y en los negociosThis paper responds to an academic imprint in which one reflects on the theoretical-methodological position for the representation of the past. It presents a dialogue about the trajectory of the professionalization of history in Veracruz. In the second part the condition of history is stated and in the third one a proposal of the social history of the economy whose node is centered on money is made, as an abstract expression of the interactions between the commercial, financial and social realities of and in busines

    TCAD 2D numerical simulations for increasing efficiency of AlGaAs – GaAs Solar Cells

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    The performance of solar cells has improved quickly in recent years, the latest research focuses on thin cells, multijunction cells, solar cells of the group III-V compounds, Tandem cells, etc. In the present work, numerical simulations are developed, using SENTAURUS TCAD as a tool, in order to obtain a solar cell model based on Galium Arsenide (GaAs). This solar cell corresponds to the so-called "Thin Films" due to the fact that can make layers thinner than we would have if we work with conventional semiconductors, such as; Silicon or Germanium; thus opening the possibility of placing the cell as a top layer within a tandem solar cell configuration with compounds of group III-V. That is why two types of simulations are performed with respect to the contact of the rear contact; one corresponds to the cell with a lower contact equal to the length of the cell and the other with a small contact of 5 μm. In addition, the cell undergoes an optimization process by modifying the geometry and doping of the layers that comprise it, in order to improve its performance. To achieve this objective, the initial conditions and the appropriate simulation parameters must be determined, which have been selected and corroborated with the literature, allowing us to arrive at coherent results and optimal models of solar cell design through numerical simulations

    Collaborative explicit plasticity framework: a conceptual scheme for the generation of plastic and group-aware user interfaces

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    The advent of new advances in mobile computing has changed the manner we do our daily work, even enabling us to perform collaborative activities. However, current groupware approaches do not offer an integrating and efficient solution that jointly tackles the flexibility and heterogeneity inherent to mobility as well as the awareness aspects intrinsic to collaborative environments. Issues related to the diversity of contexts of use are collected under the term plasticity. A great amount of tools have emerged offering a solution to some of these issues, although always focused on individual scenarios. We are working on reusing and specializing some already existing plasticity tools to the groupware design. The aim is to offer the benefits from plasticity and awareness jointly, trying to reach a real collaboration and a deeper understanding of multi-environment groupware scenarios. In particular, this paper presents a conceptual framework aimed at being a reference for the generation of plastic User Interfaces for collaborative environments in a systematic and comprehensive way. Starting from a previous conceptual framework for individual environments, inspired on the model-based approach, we introduce specific components and considerations related to groupware

    Evaluating Ecosystem Services in Transhumance Cultural Landscapes: An Interdisciplinary and Participatory Framework

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    Following the concept of ecosystem services, we propose in this article an interdisciplinary and participatory methodological framework for ecosystem services assessment and participatory decision-making in Mediterranean cultural landscapes linked with transhumant pastoralism. It is based on four sequential phases: 1. characterisation of the social-ecological network associated with transhumance, 2. preliminary identification and characterisation of ecosystem services, 3. evaluation of ecosystem services (in biophysical, socio-cultural, and economic terms), and 4. future scenario planning for the analysis of social conflicts related to ecosystem services use and trade-offs as well as the proposal of management strategies. Applying the framework to a case study on one of the major transhumance landscapes in Spain, we could identify and evaluate more than 30 ecosystem services. The framework facilitated the design of robust policy measures that aim to maintain this livestock raising model and its associated flow of ecosystem services. It also contributes to provide the basis for the implementation of adaptive co-management strategiesThis research has been financed by the Spanish Ministry for the Environment and Rural and Marine Affairs (Project 079/RN08/02.1

    Aspects of N-partite information in conformal field theories

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    We present several new results for the NN-partite information, INI_N, of spatial regions in the ground state of dd-dimensional conformal field theories. First, we show that INI_N can be written in terms of a single NN-point function of twist operators. Using this, we argue that in the limit in which all mutual separations are much greater than the regions sizes, the NN-partite information scales as INr2NΔI_N \sim r^{-2N\Delta}, where rr is the typical distance between pairs of regions and Δ\Delta is the lowest primary scaling dimension. In the case of spherical entangling surfaces, we obtain a completely explicit formula for the I4I_4 in terms of 2-, 3- and 4-point functions of the lowest-dimensional primary. Then, we consider a three-dimensional scalar field in the lattice. We verify the predicted long-distance scaling and provide strong evidence that INI_N is always positive for general regions and arbitrary NN for that theory. For the I4I_4, we find excellent numerical agreement between our general formula and the lattice result for disk regions. We also perform lattice calculations of the mutual information for more general regions and general separations both for a free scalar and a free fermion, and conjecture that, normalized by the corresponding disk entanglement entropy coefficients, the scalar result is always greater than the fermion one. Finally, we verify explicitly the equality between the NN-partite information of bulk and boundary fields in holographic theories for spherical entangling surfaces in general dimensions.Comment: 39 pages + appendices, 12 figure

    Exploring the effect of soil management intensity on taxonomic and functional diversity of ants in Mediterranean olive groves

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    Agricultural intensification is one of the major drivers behind biodiversity loss in Mediterranean agroecosystems. The intensification of olive groves as monoculture in large areas of the southern Spain has had important effects on biodiversity and ecological processes. In the present study, we explore the olive grove soil management practices effects on taxonomic and functional diversity of ants along a gradient of soil management intensity. We predict that both species richness and functional diversity decrease with an increasing intensification of olive grove soil management. We used pitfall traps to sample ants in 24 olive groves subject to different soil management regimes in southern Spain, and then compared ant species richness and functional diversity (FD). Nonploughed organic farms showed higher species richness. Ploughing was observed to be the soil management practice with the greatest negative effect on ant species richness. Three functional traits significantly responded to soil management intensity, with tibia length and head width showing a higher FD in organic farms and diet showing a lower FD in ploughed farms. The results of the present study highlight the negative effects of olive grove ploughing on ant biodiversity and provide novel evidence of the nonploughing organic farming role with respect to maintaining higher levels of ant functional diversityFinancial support was received from the Spanish Ministryof Economy and Competitiveness (Project CGL2014-53782-P

    Yield of forage, grain and biomass in eight hybrids of maize with different sowing dates and environmental conditions

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    The aim was to evaluate yield of forage, grain and biomass and fibre content of eight hybrids of maize (Rio-Grande, Arrayan, Genex 778, Narro 2010, Advance 2203, DAS 2358, P4082W and HT9150W) during two sowing seasons (spring/summer) for two consecutive years at La Laguna in Torreon, Mexico. Once the grain progression of the kernel milk line was ⅓, green forage yield (GFY), dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined. When the corncobs were fully mature, grain yield (GY) and biomass production (TBP) were determined. Weather conditions were recorded during the experiment. The results indicated that maximum temperature was higher and rainfall lower in the summer sowing and second year. Spring sowing had significantly higher yields of GFY, DM, GY and TBP compared to summer sowing. The first year of study showed significantly higher yields regarding GFY, GY and TBP, but FDN, FDA, DM content compared to the second year. The best hybrid for GFY and DM was Rio-Grande; for FDN and FDA was Advance 2203; for GY was HT9150W and finally for TBP was Arrayan. Regardless of the hybrid used and the sowing season, production of maize depended on external factors such as maximum temperature and rainfall; therefore, producers need to consider sowing in spring to avoid the negative effect of high temperatures on plant development.The aim was to evaluate yield of forage, grain and biomass and fibre content of eight hybrids of maize (Rio-Grande, Arrayan, Genex 778, Narro 2010, Advance 2203, DAS 2358, P4082W and HT9150W) during two sowing seasons (spring/summer) for two consecutive years at La Laguna in Torreon, Mexico. Once the grain progression of the kernel milk line was ⅓, green forage yield (GFY), dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined. When the corncobs were fully mature, grain yield (GY) and biomass production (TBP) were determined. Weather conditions were recorded during the experiment. The results indicated that maximum temperature was higher and rainfall lower in the summer sowing and second year. Spring sowing had significantly higher yields of GFY, DM, GY and TBP compared to summer sowing. The first year of study showed significantly higher yields regarding GFY, GY and TBP, but FDN, FDA, DM content compared to the second year. The best hybrid for GFY and DM was Rio-Grande; for FDN and FDA was Advance 2203; for GY was HT9150W and finally for TBP was Arrayan. Regardless of the hybrid used and the sowing season, production of maize depended on external factors such as maximum temperature and rainfall; therefore, producers need to consider sowing in spring to avoid the negative effect of high temperatures on plant development

    Hemolytic activity and siderophore production in different aeromonas species isolated from fish

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    P. 5612-5614The hemolytic activity and siderophore production of several strains of motile aeromonads were determined. The hemolytic activity of Aeromonas caviae and Aeromonas eucrenophila was enhanced after trypsinization of the samples. The enhancement of hemolysis was observed in strains that carried an aerolysin-like gene, detected by a PCR procedure. Siderophore production was demonstrated in all but one strain of Aeromonas jandaei. No apparent relationship was observed between the presence of plasmid DNA and hemolysis or siderophore production.S
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