1,868 research outputs found

    Crecimiento económico e inflación: el caso de México

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    The analysis focuses on the short-run dynamics of several macroeconomic variables and their relationship with the rate of inflation. The cyclical components of the variables are obtained through the Hodrick- Prescott filter. Contemporaneous correlations between the cyclical components show that inflation rates above their long-term trend are associated with below trend economic activity, employment, investment and real wages and with nominal and real interest rates above their trend. Non-contemporaneous correlations show that inflation has an adverse effect on the referred variables. Results are confirmed through “impulse-response” functions.

    Una nota sobre la conjetura del grupo de autotopismos de los presemicuerpos de Figueroa

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    In [4] was stated the following conjecture: If a Figueroa’s presemifield P(K; alfa; beta; A;B) admits an autotopism of order a p-primitive prime divisor of p^n-1, then its autotopism group is isomorphic to a subgroup of GL(K) x GL(K). In [5] this conjecture was settled under an additional normality condition. In this article, we show that the assumption in the hypothesis of the conjecture is necessary in the sense that there exist a Figueroa’s presemifield, that does not admit such autotopism, for which the conjecture is not met.En [4] se estableció la siguiente conjetura: Si un presemicuerpo de Figueroa P(K; alfa; beta; A;B) admite un autotopismo de orden un divisor primo p-primitivo de p^n-1, entonces su grupo autotopismo es isomórfo a un subgrupo de GL(K) x GL(K). En [5] esta conjetura se resolvió bajo una condición adicional de normalidad.En este artículo, mostramos que la suposición hecha en la hipótesis de la conjetura es necesaria en el sentido de que existe un presemicuerpo de Figueroa, que no admite tal autotopismo, para el cual la conjetura no se cumple

    Effect of shear processing on the linear viscoelastic behaviour and microstructure of bitumen/montmorillonite/MDI ternary composites

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    Polymer modified bitumens (PMBs) have largely been utilized as a construction material. However, lack of affinity between bitumen and polymer leads to phase separation, and eventually, performance depletion. In this paper, alternative formulations of bitumen with an organically-modified montmorillonite (OMMT) Cloisite 20A® and polymeric methylene diphenyl diisocyanate (MDI) were prepared by melt blending. Their comprehensive rheological characterization evidenced improved linear viscoelastic properties when OMMT is added, revealing a noticeable structural reinforcement and thermal stability. Rheological data also showed that MDI-involved reactions control the composite end properties, being greatly influenced by the shear conditions applied

    Volatilidad del tipo de cambio y tasas de interés en México: 1996-2001

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    It is argued that in Mexico there is not a fear of floating in the Calvo-Reinhart sense and that the market, as a result of the monetary policy instrument (corto), has determined a reatively stable exchange rate and more volatile interest rates. Thus, thé instantaneous interest rate response to exogenous shocks limits the exchange rate role as a buffer to the referred disturbances. Empirical evidence shows that explicit interest rate targets result in higher exchange rate volatility and lower interest rate variability.volatility, exchange rate, interest rates

    A Simple Risk Assesment Method for Continental Waters, Based on Screening Contaminants of Emerging Concern

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    Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] With the aim to build a simple alert system that may be of extended use, a screening for contaminants of emerging concern (CECs) is carried out in the Mero-Barcés hydrographic watershed, in Cecebre, A Coruña, NW Spain, which feeds the reservoir that supplies drinking water to ≈400 000 inhabitants in the area. Water samples are collected for five years (2015–2019) at six different sampling points, to assess the presence and potential risk of CECs, including some widely used drugs: clofibric acid, paracetamol carbamazepine, diclofenac, ibuprofen, ofloxacin, ketoprofen, and sotalol; an alkaloid: caffeine; synthetic flavourings: galaxolide and tonalide; and a plasticiser: bisphenol A. The most abundant CECs occurring are ibuprofen (>2µg L−1), diclofenac, caffeine, and galaxolide. Samples of treated drinking water show a certain degree of CECs abatement. The presence of nonpolar substances, banned in the EU nowadays, is confirmed. A snapshot of sediments is sampled in 2018–2019, and PAHs and PCBs are quantified, the former being mainly of pyrogenic origin. Based on known properties of quantifiable substances, a traffic-light system is developed for risk assessment of the state of continental waters, a strategy that may be useful for decission-makers to implement environmental remediation policiesThis research has received support from the Spanish Ministerio de Ciencia e Innovación, through grant TED2021-132667B-I00, funded by the EU NextGeneration EU/PRTR through project MCIN/AEI/10.13039/501100011033. Financial support was also provided by the regional government of the Xunta de Galicia through project GRC/ED431C 2023/33. EMALCSA promoted this piece of research and contributed, as well, through project CFIS-ECOPHARMA and through the Cátedra EMALCSA-UDC. Funding to publish this article under open access was provided by Universidade da Coruña/CISUG.Xunta de Galicia; GRC/ED431C 2023/3

    Sectores productivos y espacios de conflicto: pesca y petróleo en la sonda de Campeche

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    Objetivo y planteamiento del problema: La Sonda de Campeche es una zona marítima del Golfo de México en donde por más de 60 años se ha realizado la explotación de dos importantes recursos naturales para la economía nacional y regional de esta región: las pesquerías del camarón y la extracción de petróleo. Ambas actividades, aunque comparten el mismo espacio, son completamente diferentes en cuanto a la extracción de sus respectivos productos. Esencialmente, la actividad pesquera del camarón está sujeta a varios condicionamientos para su desarrollo: primero, de carácter físico-biológico y territorial; segundo, a las relaciones comerciales de carácter internacional, nacional y local; tercero, a las normatividades y reglamentaciones de carácter gubernamental y de observancia pública por parte del sector involucrado en la actividad. En tanto que la actividad petrolera está sujeta a otros condicionamientos: primero, existe una demanda del mercado nacional e internacional; segundo, es un energético de la cual depende la industria y la economía de los países industrializados y no industrializados. El objetivo del trabajo es presentar un panorama de ambas actividades productivas en un mismo espacio marítimo territorial, hoy día en conflicto por la intervención de diversos actores sociales y agentes económicos que dan pie a la reconfiguración del territorio. Esto se hace mediante la identificación de diversas escalas de análisis espacial por etapas. Conclusiones: Se señalan los intereses de los actores en espacios de conflictos, lo cual impide el desarrollo articulador de ambos sectores productivos importantes para la región y para los intereses geoestratégicos nacionales e internacionales

    Correlation-mediated processes for electron-induced switching between Néel states of Fe antiferromagnetic chains

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    The controlled switching between two quasistable Néel states in adsorbed antiferromagnetic Fe chains has recently been achieved by Loth et al. using tunneling electrons from an STM tip. In order to rationalize their data, we evaluate the rate of tunneling electron-induced switching between the Néel states. Good agreement is found with the experiment, permitting us to identify three switching mechanisms: (i) low STM voltage direct electron-induced transitions, (ii) intermediate STM voltage switching via spin-wave-like excitation, and (iii) high STM voltage transitions mediated by domain-wall formation. Spin correlations in the antiferromagnetic chains are the switching driving force, leading to a marked chain-size dependence. © 2013 American Physical Society.M.Y. and X. C. acknowledge financial support through Spain’s MINECO under Contract No. TEC2009-06986.Peer Reviewe
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