The silicon stable isotope distribution along the GEOVIDE section (GEOTRACES GA-01) of the North Atlantic Ocean

The stable isotope composition of dissolved silicon in seawater (δ30SiDSi) was examined at 10 stations along the GEOVIDE section (GEOTRACES GA-01), spanning the North Atlantic Ocean (40–60∘ N) and Labrador Sea. Variations in δ30SiDSi below 500 m were closely tied to the distribution of water masses. Higher δ30SiDSi values are associated with intermediate and deep water masses of northern Atlantic or Arctic Ocean origin, whilst lower δ30SiDSi values are associated with DSi-rich waters sourced ultimately from the Southern Ocean. Correspondingly, the lowest δ30SiDSi values were observed in the deep and abyssal eastern North Atlantic, where dense southern-sourced waters dominate. The extent to which the spreading of water masses influences the δ30SiDSi distribution is marked clearly by Labrador Sea Water (LSW), whose high δ30SiDSi signature is visible not only within its region of formation within the Labrador and Irminger seas, but also throughout the mid-depth western and eastern North Atlantic Ocean. Both δ30SiDSi and hydrographic parameters document the circulation of LSW into the eastern North Atlantic, where it overlies southern-sourced Lower Deep Water. The GEOVIDE δ30SiDSi distribution thus provides a clear view of the direct interaction between subpolar/polar water masses of northern and southern origin, and allow examination of the extent to which these far-field signals influence the local δ30SiDSi distribution

La Contabilidad Financiera y la Contabilidad de Costes en SAP R/3

El lanzamiento en 1992 de la nueva versión de SAP R/3 por la empresa alemana SAP AG encumbró a ésta al éxito y aún hoy, transcurridos ya diez años, sigue líder en el sector de empresas que abastecen de programas informáticos ERP (Enterprise Resource Planning - Sistemas Integrados de Gestión) a las empresas. Este trabajo tiene como objetivo analizar los módulos que dicho programa dedica a la Contabilidad Financiera y a la Contabilidad de Costes, prestando atención a cada uno de las funciones que lo componen. Por último, se ofrece una visión sobre los procesos de implantación en las empresas con relación a tales módulos para de este modo, conocer las principales dificultades con las que se encuentran a la hora de aplicar un programa de tales características, así como las ventajas que aporta a la gestión empresarial

Just Another Day: A Comic About Brexit

The uncertainty generated by Brexit has motivated us to prepare a comic that explains in an educative and informative way the different options that Europeans and their families have available to minimise the impact of Brexit. Concept and story by Francisco de la Mora and Ernesto Priego. Art by Ricardo Peláez. Second page text and information by Manuel Padilla Behar. The text in the comic was translated from the original Spanish into English by Ernesto Priego. Graphic design by Daniela Rocha. With special thanks to Helen Calderon for proofreading and feedback

Universal properties of correlation transfer in integrate-and-fire neurons

One of the fundamental characteristics of a nonlinear system is how it transfers correlations in its inputs to correlations in its outputs. This is particularly important in the nervous system, where correlations between spiking neurons are prominent. Using linear response and asymptotic methods for pairs of unconnected integrate-and-fire (IF) neurons receiving white noise inputs, we show that this correlation transfer depends on the output spike firing rate in a strong, stereotyped manner, and is, surprisingly, almost independent of the interspike variance. For cells receiving heterogeneous inputs, we further show that correlation increases with the geometric mean spiking rate in the same stereotyped manner, greatly extending the generality of this relationship. We present an immediate consequence of this relationship for population coding via tuning curves

Una revisión sobre la consolidación empresarial en España

La continua y veloz evolución que están experimentando los mercados actuales de todo el mundo, han propiciado la concentración de numerosas empresas con la finalidad de dar respuesta a las estrategias de crecimiento y la mejora de desarrollo que esta nueva situación conlleva. La importancia del fenómeno de concentración empresarial en España en los últimos años, justifica la necesidad de realizar un nuevo estudio sobre la situación actual española. El presente trabajo toma como unidad de análisis el total de grupos que cotizan en la actualidad en la Bolsa española, tratando de mostrar su realidad. De este modo, permite conocer la estabilidad que tienen dentro del mercado español y, al mismo tiempo, aproximamos al método de consolidación empleado, las características de las sociedades dependientes y otros rasgos claves que faciliten un mayor conocimiento de tales entidades

Response of Spiking Neurons to Correlated Inputs

The effect of a temporally correlated afferent current on the firing rate of a leaky integrate-and-fire (LIF) neuron is studied. This current is characterized in terms of rates, auto and cross-correlations, and correlation time scale $\tau_c$ of excitatory and inhibitory inputs. The output rate $\nu_{out}$ is calculated in the Fokker-Planck (FP) formalism in the limit of both small and large $\tau_c$ compared to the membrane time constant $\tau$ of the neuron. By simulations we check the analytical results, provide an interpolation valid for all $\tau_c$ and study the neuron's response to rapid changes in the correlation magnitude.Comment: 4 pages, 3 figure

Potentiation of morphine-induced antinociception and locomotion by citalopram is accompanied by anxiolytic-like effects

Morphine and related opioids are the mainstay of analgesic treatment, especially in patients suffering chronic pain. Besides their antinociceptive effects they may also exhibit anxiolytic-like properties that could contribute to pain relief. The pharmacological manipulation of the serotonergic system may not only modulate pain transmission and processing but also other behavioral effects of opioids. The present study aimed to analyze the effect of the concurrent treatment with citalopram, a selective serotonin reuptake inhibitor, on the antinociceptive, locomotor and anxiety-related effects induced by acute and subchronic administration of morphine in mice. Citalopram (15 mg/kg) enhanced the acute antinociceptive effects of morphine when concurrently administered as evidenced by a two-fold increase in the ED50 for the antinociceptive effect of morphine in the hot-plate test. Chronic studies also revealed that concurrent citalopram treatment (15 mg/kg) delayed the development of tolerance to the thermal antinociceptive effects of morphine. Additionally, morphine-induced hyperlocomotion was potentiated by citalopram as assessed in the open-field test and in the spontaneous activity recording in the home cage, a behavioral outcome to which tolerance or desensitization was not developed. Interestingly, chronic administration of both drugs promoted an anxiolytic effect as evidenced by the increased central activity in the open field test. Future investigations on this pharmacological interaction, such as the possible translational research in clinics, might have consequences in future strategies for the therapeutic management of pain.This research was supported by the grant SAF2010-15663 from the Spanish Government (MINECO). We thank David Ramos and Raquel Lanza for their technical assistance in handling living animals. We kindly appreciate Belen Palacio support for video footage and editing and Dr. Albert Adell for the critical reading of the manuscript

Plant-Growth Promoting Endophytic Bacteria and Their Role for Maize Acclimatation to Abiotic Stress

In order to grow, reproduce, and defend themselves, maize plants use various strategies to obtain adaptive advantages in varying conditions, for example, to tolerate abiotic stress (e.g., drought or heat due to climate change). One of these strategies is the establishment of interactions with plant-growth-promoting bacteria. Bacteria can be associated with plants in the rhizosphere, rhizoplane, or as endophytes. Recent evidence suggest that modern agricultural practices are detrimental to these beneficial plant-microbe interactions, and reservoirs like traditional agroecosystems called milpas, emerge as sources of microbiota associated with maize crops, with increased diversity and beneficial functions. Particularly, bacterial endophytes associated with native maize from milpas show promising features for their use as plant-growth-promoting inoculates, however, it is necessary to first understand the mechanisms known for beneficial functions of endophytes associated with maize and other plants. Here, we review the mechanisms of beneficial interactions between plants and endophytic bacteria, with emphasis on maize and with mentions of recent findings on maize landraces from milpa systems