3,578 research outputs found
Input cost, capacity utilization and substitution in the short run
This article studies the behavior of input cost shares in an environment where labor is costly to adjust, materials can be adjusted at no cost and capital is fixed. A model relating cost shares with relative prices and adjustment costs is proposed, allowing joint estimation of the elasticity of substitution and the adjustment cost function, which is an unknown function of the utilization capacity. Based on a panel of more than 700 manufacturing firms, we find evidence of strong input share variations according to the degree of capacity utilization. The estimated shapes of adjustment costs curves of labor are in agreement with our theoretical model, and we obtain sensible elasticities of substitution estimates. Based on such estimates, we find evidence of a negative (positive) bias in downturns (recoveries) in conventional productivity growth measures
Analysis of NPF and NRT transporter families regarding the nitrate nutrition in maritime pine (Pinus pinaster)
Nitrogen is an essential element for life and the main limiting nutrient for plant growth and development1. The main forms of inorganic nitrogen in soils are nitrate and ammonium, which relative abundances depend on environmental conditions such as temperature. In agricultural soils the most abundant nitrogen form is nitrate because the use of chemical fertilizers however in natural ecosystems nitrogen soil composition can be more complex. Conifers are tree gymnosperms with a wide distribution although their large forests dominate the boreal ecosystems where nitrification is limited and ammonium is the main nitrogen soil source2. In this context, conifers have an appreciable tolerance to ammonium.
Maritime pine (Pinus pinaster Aiton) is a conifer from the western Mediterranean region of high economic and ecological interest in Spain, France and Portugal. This pine is also a research model tree with different genomic resources such as a reference transcriptome and a gene expression atlas3. Taking advantage of these resources the members of the NPF and NRT transporter families involved in nitrate uptake and transport have been identified and analyzed in maritime pine4. Among the transporter families, the NRT3 one is expanded and composed by six members. The capacity of maritime pine to use nitrate or ammonium has been analyzed in seedlings. The development and growth responses to nitrate nutrition are comparable to ammonium supply. At molecular level, there are strong gene expressions for genes involved in nitrate uptake and assimilation such as Nitrate Reductase, Nitrite Reductase, Glutamine Synthetase 1a, three NRT3 genes and different NPF family members in the different organs. Since the NPF proteins can transport different metabolites, peptides and hormones, the NPF transporters involved in nitrate transport are being identified.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
This project was supported by the grant MicroNUpE, BIO2015-73512-JIN; MINECO/AEI/FEDER, UE. JMVM was supported by a grant from the Spanish Ministerio de Educación y Formación Profesional (FPU17/03517) and FO by a grant from the Universidad de Málaga (Programa Operativo de Empleo Juvenil vía SNJG, UMAJI11, FEDER, FSE, Junta de Andalucía)
Transcriptomics of ammonium nutrition in the conifer Pinus pinaster Aiton
Nitrogen is an important element for all living beings because it is part of macromolecules as significant
as nucleic acids or amino acids. For plants, it constitutes a limiting factor in their growth and development1
due to their low natural availability in soils thus limiting primary production in ecosystems2.
Conifers are a group of gymnosperm plants that form large forest extensions of vegetation, being the main
constituents of forests in boreal ecosystems3 where ammonium is the main source of inorganic nitrogen4.
Due to the characteristics of the soils in which conifers usually grow, these plants have developed a high
tolerance to the presence of ammonium, which may constitute their main source of inorganic nitrogen5.
The maritime pine (Pinus pinaster Aiton) is a conifer that has a wide distribution in the western
Mediterranean area and has been widely used in reforestation, soil stabilization tasks and industrially. In
recent years, maritime pine has been the subject of multiple omic studies that have resulted in the
acquisition of important tools and resources6,7.
The present work is focused on the analysis of the ammonium uptake and management efficiency, and its
relationship with the biomass accumulation in maritime pine. For this purpose, several experiments have
been developed in which pine seedlings have undergone different levels of ammonium nutrition, both in the
short and long term. As a result of short-term experiments, the characterization of transcriptomic response
to the process of ammonium nutrition (uptake and assimilation) is being studied at mRNA, lncRNA and
miRNA level in roots. In relation to long-term experiments, ten different provenances of maritime pine
seedlings were treated with different ammonium levels and the biomass changes were measured. The results
obtained suggest the existence a certain phenotypic plasticity grade for this conifer.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
This project was supported by a grant form the Spanish Ministerio de Ciencia, Innovación y Universidades
(MicroNUpE, BIO2015-73512-JIN; MINECO/AEI/FEDER, UE). FO was supported by a grant from the
Universidad de Málaga (Programa Operativo de Empleo Juvenil vía SNJG, UMAJI11, FEDER, FSE, Junta
de Andalucía) and JMVM by a grant from the Spanish Ministerio de Educación y Formación Profesional
(FPU17/03517
The Correlated Block Renormalization Group
We formulate the standard real-space renormalization group method in a way
which takes into account the correlation between blocks. This is achieved in a
dynamical way by means of operators which reflect the influence on a given
block of its neighbours. We illustrate our method in the example of the
tight-binding model in 1D and 2D for various types of boundary conditions.Comment: LATEX file, 18 pages, 7 figures available upon reques
Ab initio studies of ethanol dehydrogenation at binary AuPd nanocatalysts
Producción CientíficaDensity Functional Theory (DFT) simulations have been performed to study ethanol anaerobic oxidation at 10-atom binary gold–palladium clusters with varying compositions, ranging from 0% to 100% gold content. For each case, we have studied the loss of two hydrogen atoms, the desorption of acetaldehyde, and recombination of hydrogen into gas-phase H2. The results show that alloying produces sizable changes in the reaction barriers and in the stability of the intermediate species, which are related to different intrinsic reactivities of palladium and gold.Ministerio de Economía, Industria y Competitividad (Project MAT2014-54378-R)Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. A050U14
Huellas del joven Martínez Ruiz en el Azorín adulto: sobre el sistema ecléctico de la tetralogía crítica (1912-1915)
En este artículo se salvará la aparente distancia que separa al joven José Martínez Ruiz (1873-1967), simpatizante del anarquismo, del Azorín conservador en que se convirtió en su madurez. Para ello se presentará su tetralogía crítica, formada por Lecturas españolas (1912), Clásicos y modernos (1913), Los valores literarios (1914) y Al margen de los clásicos (1915), como el resultado de un anhelo juvenil por construir una historia de la literatura española. Se realizará un cotejo entre estas cuatro obras y el libro La evolución de la crítica, de 1899, con el objetivo de determinar qué influencia tuvieron las diversas escuelas teóricas examinadas en este opúsculo en su crítica literaria de madurez. De este análisis se concluirá que es posible apreciar una continuidad entre las metodologías críticas analizadas en La evolución de la crítica y las practicadas por el Azorín adulto. Asimismo, se propondrá que su labor crítica de madurez se sostiene sobre un sistema amplio y ecléctico heredado de estas teorías con las que se familiarizó en su juventud.This article expects to overcome the apparent distance noticed between the young José Martínez Ruiz (1873-1967), sympathizer of the anarchism, to the conservative author that later became known as Azorín. This way, his critical tetralogy (formed by Lecturas españolas, 1912, Clásicos y modernos, 1913, Los valores literarios, 1914, and Al margen de los clásicos, 1915) will be presented as a result of a young desire of writing a history of the Spanish literature. After this, the influence of his 1899 work La evolución de la crítica in the books mentioned above will be analyzed. In addition, it will be concluded that it is possible to appreciate continuity between the critical methodologies that Martínez Ruiz analyzed in La evolución de la crítica and those which he displayed to write his critical tetralogy. Finally, it will be proposed that his adult critical methodology is based on an eclectic system, which derives from the different theories of literary criticism that he learnt as a young writer
La experiencia subjetiva de la discapacidad: narrativas sobre el desahucio corporal y emocional
Comunicación presentada en el Grupo de Trabajo GT-26 "Sociología del cuerpo y de las emociones", dentro del XXIX Congreso Latinoamericano de Sociología. Santiago de Chile, 29 septiembre - 4 octubre de 2013.La modernidad nos ha constituido como “individuos”: individuos políticos, dotados de derechos y deberes, e individuos económicos, portadores de un interés egoísta instrumental. Es una individualidad contradictoria, dado que su primera dimensión ha de orientarse hacia el bien común, lo público, y la segunda hacia el privado. Son conjugables porque, además de individuos, somos sujetos, esto es, estamos dotados de racionalidad. A través de nuestro pensamiento racional podemos evaluar y decidir en cada momento qué hacer sin atentar contra nuestra individualidad; es decir, a qué darle prioridad, desde una racionalidad weberiana de carácter finitista más bien que instrumental. Ese individuo-sujeto moderno no tiene cuerpo ni sentimientos, actúa bajo principios neutros, asépticos, de carácter deliberativo, es un ser abstracto dotado de voluntarismo racional. Las personas con discapacidad han quedado excluidas de esa doble imputación y revelan, desde la “desnudez” de su pura condición de personas, la fisura entre la imputación y la existencia real. Tomando como referencia dos historias de vida realizadas para el proyecto Quali-TYDES (Qualitative tracking with Young Disabled People in European States, del programa ECRP de la European Science Foundation) veremos como emerge, en ellas, una condición emocional y corporal en situación de “desahucio”. Suprimidos el voluntarismo y el egoísmo del individuo moderno, así como la racionalidad del sujeto moderno, las emociones quedan bloqueadas y los cuerpos manifiestan, en su condición ineficiente (no por serlo de hecho, sino habérseles adscrito dicha asignación), la precaria condición de nuestra existencia. Cuerpos y emociones, doblegados por el capitalismo neoliberal-global, a través de la discapacidad indican las claves estructurales de nuestro cotidiano sometimiento.La elaboración de esta comunicación y su presentación en el congreso se inscriben en el proyecto de investigación “Quali-TYDES” (Qualitative Tracking with Young Disabled in European States), European Collaborative Research Projects in the Social Sciences – European Science Foundation (ref. 09-ECRP-032).Peer reviewe
An unexpected actor in ammonium assimilation in conifer trees
Conifers are tree species with enormous environmental and economic interests but with several characteristics that complicate their investigation (big size, secondary compounds, large long-life cycles, megagenomes…). However, they are well adapted to ammonium-rich soils being a good model to study ammonium assimilation in plants. Although they have a special feature, only two glutamine synthetase (GS, EC 6.3.1.2) genes, GS1a and GS1b, coding for cytosolic proteins, have been identified. In angiosperms and in the gymnosperm Ginkgo biloba there are two types of this enzyme responsible of the ammonium assimilation: GS1 expressed in the cytosol and GS2 in the plastids. Until the date, the searches of new GS1 and GS2 genes in conifers have been made with classical biochemical and molecular biology techniques without satisfactory results.
In the present context, the emergence of the next generation sequencing (NGS) techniques has open new opportunities in the resolution of old problems. They have allowed the whole sequencing of the massive conifer genomes and the analysis of their transcriptomes. Thus, in the framework of the European project ProCoGen, a gene expression atlas of the tissues of one-month seedlings was carried out using laser capture microdissection (LCM) and massive sequencing in maritime pine (Pinus pinaster), which is a conifer tree from the Southwestern Mediterranean region1. From the analysis of this work, a new gene coding for a new putative cytosolic GS has been identified, PpGS1c.
1Cañas, RA et al. (2017). Plant J, 91. 1064-1087Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
Project funding by Ministerio de Economía y Competitividad BIO2015-69285-R and MicroNUpE (BIO2015-73512-JIN; MINECO/AEI/FEDER, UE
US biofuel market persistence and mean reversion properties.
This paper investigates the market persistence and mean reversion properties for corn, bioethanol and gasoline prices in the US biofuel industry, evaluating long memory effects with fractional integration techniques from January 1982 to May 2022 with USDA data. Empirical results show evidence of no mean reversion properties for the prices in the three series though some support of it is found when the differences of bioethanol and gasoline are taken with respect to corn. Thus, external shocks in the original series are expected to remain persistent and would require additional policy measures to recover the original trend. Furthermore, the impact of Covid on the time series has been analyzed by comparing the scenarios pre and post pandemic, finding evidence of no major changes in the integration orders in all the series under analysis.post-print1158 K
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