Ultra-Fast Activity and Intraday Market Quality

This paper studies the intraday relationship between ultra-fast machine-driven activity (UFA) and market quality in automated equity markets. We find that higher UFA is associated with lower intraday market quality (greater quoted and effective spreads and lower depth). This effect is economically significant, and robust to different specifications, endogeneity tests, and alternative measures of UFA. Our results hold after controlling for volatility, periods of unusually high UFA (a proxy for quote stuffing), and periods where UFA is primarily driven by fleeting orders inside the spread (a proxy for spoofing and competition between liquidity providers)José Penalva acknowledges financial support from the Fundacin BBVA (Ayuda Fundación BBVA a Investigadores y Creadores Culturales 2015, beca Leonardo) and the Ministerio de Ciencia y Teconología grant ECO2012-36559 and ECO2015-69205-P (with Mikel Tapia)

n-3 AGPICL en la reversión de la esteatosis hepática: el papel de la ACOX y CAT

The aim of this study was to investigate the roles of the Acyl co-enzyme A oxidase (ACOX), carnitine acyl transferase I (CAT-1) and activating protein 1 (AP-1) in the reversal of hepatic steatosis with dietary change and n-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) supplementation. Male C57BL/6J mice were given either a control diet (CD) or a high fat diet (HFD) for 12 weeks, and then continued with the CD or CD plus n-3 LCPUFA for eight weeks. After this period, body and adipose visceral tissue weight were analyzed and liver samples were taken to measure ACOX, CAT-1 and c-jun levels. The dietary change from HFD to a norm caloric diet plus n-3 LCPUFA supplementation significantly reduced liver steatosis and adipose tissue: body weight ratio, along with an increase in the hepatic ACOX and CAT-1 levels and normalization of AP-1 expression that could favor the fatty acid beta-oxidation over lipogenesis and regulate inflammation. These results provide new data on the enzymatic metabolism underlying dietary change to a norm caloric diet plus n-3 LCPUFA supplementation.El objetivo de este estudio fue investigar el rol de las enzimas Acil coenzima A oxidasa (ACOX) y Acil carnitina transferasa 1 (CAT-1), además del factor de transcripción, Proteína activadora 1 (AP-1) en la reversión de la esteatosis hepática mediante cambio de dieta más suplementación con Ácidos grasos poliinsaturados de cadena larga omega tres (AGPICL n-3). Ratones macho de la cepa C57BL/6J fueron alimentados con dieta control (DC) o alta en grasas (DAG) durante 12 semanas, luego continuaron con DC con o sin suplementación de AGPICL n-3 durante 8 semanas. Después de este período, se analizó el peso corporal y del tejido adiposo visceral; en las muestras hepáticas se evaluaron los niveles de ACOX, CAT-1 y AP-1. El cambio a dieta control más suplementación con AGPICL n-3 reduce significativamente la esteatosis hepática y la relación tejido adiposo/peso corporal, acompañado de un incremento en los niveles hepáticos de ACOX y CAT-1 y normalización de la expresión de AP-1; regulando la inflamación y favoreciendo la beta oxidación sobre la lipogénesis. Estos resultados proveen nuevos datos sobre el metabolismo enzimático cuando se realiza cambio a dieta control más suplementación con AGPICL n-3

Organized Disassembly of Photosynthesis During Programmed Cell Death Mediated By Long Chain Bases.

In plants, pathogen triggered programmed cell death (PCD) is frequently mediated by polar lipid molecules referred as long chain bases (LCBs) or ceramides. PCD interceded by LCBs is a well-organized process where several cell organelles play important roles. In fact, light-dependent reactions in the chloroplast have been proposed as major players during PCD, however, the functional aspects of the chloroplast during PCD are largely unknown. For this reason, we investigated events that lead to disassembly of the chloroplast during PCD mediated by LCBs. To do so, LCB elevation was induced with Pseudomonas syringae pv. tomato (a non-host pathogen) or Fumonisin B1 in Phaseolus vulgaris. Then, we performed biochemical tests to detect PCD triggering events (phytosphingosine rises, MPK activation and H2O2 generation) followed by chloroplast structural and functional tests. Observations of the chloroplast, via optical phenotyping methods combined with microscopy, indicated that the loss of photosynthetic linear electron transport coincides with the organized ultrastructure disassembly. In addition, structural changes occurred in parallel with accumulation of H2O2 inside the chloroplast. These features revealed the collapse of chloroplast integrity and function as a mechanism leading to the irreversible execution of the PCD promoted by LCBs

Development of sustainable tools (Database and software) for Marine Litter Data management

Entregable del proyecto CleanAtlanticEste entregable describe diversas herramientas de utilidad para la gestión de datos de basura marina

Activation of microglia in specific hypothalamic nuclei and the cerebellum of adult rats exposed to neonatal overnutrition

Much attention has been drawn to the possible involvement of hypothalamic inflammation in the pathogenesis of metabolic disorders, especially in response to a high-fat diet. Microglia, the macrophages of the central nervous system, can be activated by proinflammatory signals resulting in the local production of specific interleukins and cytokines, which in turn could exacerbate the pathogenic process. Because obesity itself is considered to be a state of chronic inflammation, we evaluated whether being overweight results in microglial activation in the hypothalamus of rats on a normal diet. Accordingly, we used a model of neonatal overnutrition that entailed adjustment of litter size at birth (small litters: four pups/dam versus normal litters: 12 pups/dam) and resulted in a 15% increase in bodyweight and increased circulating leptin levels at postnatal day 60. Rats that were overnourished during neonatal life had an increased number of activated microglia in specific hypothalamic areas such as the ventromedial hypothalamus, which is an important site for metabolic control. However, this effect was not confined to the hypothalamus because significant microglial activation was also observed in the cerebellar white matter. There was no change in circulating tumour necrosis factor (TNF) α levels or TNFα mRNA levels in either the hypothalamus or cerebellum. Interleukin (IL)6 protein levels were higher in both the hypothalamus and cerebellum, with no change in IL6 mRNA levels. Because circulating IL6 levels were elevated, this rise in central IL6 could be a result of increased uptake. Thus, activation of microglia occurs in adult rats exposed to neonatal overnutrition and a moderate increase in weight gain on a normal diet, possibly representing a secondary response to systemic inflammation. Moreover, this activation could result in local changes in specific hypothalamic nuclei that in turn further deregulate metabolic homeostasi

Evidencias mineralógicas y geoquímicas de mezcla incompleta de magmas en la Sierra de las Cruces, Cinturón Volcánico Mexicano

Received: 19/05/2011 / Accepted: 12/04/2013.Pliocene – Pleistocene lava flows, mainly of dacitic composition, are exposed in the Sierra de las Cruces (SC) volcanic range within the Mexican Volcanic Belt (MVB). SC volcanic rocks are porphyritic, generally containing an assemblage of plagioclase + amphibole + orthopyroxene ± clinopyroxene ± quartz ± Fe-Ti oxides. Most of them exhibit diverse mineralogical and geochemical features that attest a magma mixing and mingling processes with concomitant fractional crystallization in which a small volume of hot andesite magma injects into dacitic magma. Both rock types are probably derived from partial melting of continental crust at different levels. The evidences of magma mixing and mingling include: (a) normal and sieved plagioclases in the same sample, rounded and embayed crystals, and armoured rims over the dissolved crystal surfaces; (b) subrounded, vesicular magmatic enclaves, ranging from a few millimeters to ~20 centimeters in size, with plagioclase + orthopyroxene + amphibole + quartz ± olivine ± Fe-Ti-oxides assemblage; (c) mineral chemistry evidence such as crystals with reaction rims or heterogeneous plagioclase compositions (inverse and oscillatory zoning or normally and inversely zoned crystals) in the same sample; and (d) elemental geochemical variations and trace-element ratio more akin to magma mixing and to some extent diffusion process. These andesitic enclaves could be considered as portions of the intermediate magma that did not mix completely (mingling) with the felsic host lavas, confirming the major role of magma mixing and mingling processes in the overall evolution of the MVB.En la Sierra de las Cruces (SC), Cinturón Volcánico Mexicano (CVM), se encuentran expuestos flujos de lava, principalmente de composición dacítica, del Plioceno-Pleistoceno. Las rocas volcánicas de la SC son de textura porfirítica, conteniendo plagioclasa + anfibol + ortopiroxeno ± clinopiroxeno ± cuarzo ± óxidos de Fe-Ti. La mayor parte de ellas exhiben diversas características que indican un proceso de mezcla incompleta de magmas, con una cristalización fraccionada concomitante, en la que un pequeño volumen de un magma andesítico caliente es inyectado a un magma dacítico. Es probable que ambos tipos de roca se hayan generado por fusión parcial a diferentes niveles de la corteza continental. Las evidencias de la mezcla incompleta de magmas incluyen: (a) plagioclasas con texturas normal y anubarrada en la misma muestra, cristales redondeados y corroídos, y bordes de reacción en superficies de cristal disueltas; (b) enclaves magmáticos subredondeados y vesiculares, que ocurren en dimensiones de un pocos milímetros a ~20 centímetros de diámetro, con plagioclasa + ortopiroxeno + anfíbol + cuarzo ± olivino ± óxidos de Fe-Ti; (c) química de minerales, que incluye cristales con bordes de reacción o plagioclasas de composición heterogénea (zonación inversa y oscilatoria o cristales con zonación normal e inversa) en la misma muestra; y (d) variaciones geoquímicas de elementos y relaciones de elementos traza explicables por una mezcla de magmas y por un proceso de difusión. Los enclaves andesíticos podrían considerarse como porciones de magma intermedio que no se mezcló con los líquidos dacíticos receptores, lo que confirma la importancia de los procesos de mezcla incompleta de magmas en la evolución magmática del CVM.Universidad Autónoma de Nuevo LeónDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Valproic acid restricts mast cell activation by Listeria monocytogenes.

Mast cells (MC) play a central role in the early containment of bacterial infections, such as that caused by Listeria monocytogenes (L.m). The mechanisms of MC activation induced by L.m infection are well known, so it is possible to evaluate whether they are susceptible to targeting and modulation by different drugs. Recent evidence indicates that valproic acid (VPA) inhibits the immune response which favors L.m pathogenesis in vivo. Herein, we examined the immunomodulatory effect of VPA on L.m-mediated MC activation. To this end, bone marrow-derived mast cells (BMMC) were pre-incubated with VPA and then stimulated with L.m. We found that VPA reduced MC degranulation and cytokine release induced by L.m. MC activation during L.m infection relies on Toll-Like Receptor 2 (TLR2) engagement, however VPA treatment did not affect MC TLR2 cell surface expression. Moreover, VPA was able to decrease MC activation by the classic TLR2 ligands, peptidoglycan and lipopeptide Pam3CSK4. VPA also reduced cytokine production in response to Listeriolysin O (LLO), which activates MC by a TLR2-independent mechanism. In addition, VPA decreased the activation of critical events on MC signaling cascades, such as the increase on intracellular Ca2+ and phosphorylation of p38, ERK1/2 and -p65 subunit of NF-κB. Altogether, our data demonstrate that VPA affects key cell signaling events that regulate MC activation following L.m infection. These results indicate that VPA can modulate the functional activity of different immune cells that participate in the control of L.m infection

Una herramienta didáctica para la enseñanza de la teoría de juegos mediante Internet

Este trabajo presenta una herramienta didáctica diseñada para facilitar la realización de prácticas participativas con alumnos vía Internet. La herramienta se centra en el aprendizaje de conceptos y problemas propios de las interacciones sociales.  El programa desarrollado se ofrece gratuitamente a la comunidad académica en la direcciónhttp://www.insisoc.org/tragedia_de_los_comunes.html.  El artículo describe el programa informático y discute la utilidad de este tipo de herramientas participativas para la enseñanza, y en particular para el estudio de situaciones en las que los resultados para un individuo (alumno) dependen no sólo de sus decisiones, sino también de las decisiones del resto de individuos con los que interactúa. Abstract This paper presents a computer program designed to conduct classroom experiments through the Internet. The program is aimed to facilitate the teaching of several concepts and issues that are characteristic of various social interactions. The computer program is freely available at http://www.insisoc.org/tragedia_de_los_comunes.html. The paper describes the computer program and discusses the usefulness of this kind of participative tools for learning, focusing particularly on those cases in which the results for a player (student) depend not only on their own decisions, but also on the decisions of the other students

Transcriptomic profiles and diagnostic biomarkers in the Mediterranean seagrasses Posidonia oceanica and Cymodocea nodosa reveal mechanistic insights of adaptative strategies upon desalination brine stress

Seawater desalination by reverse osmosis is growing exponentially due to water scarcity. Byproducts of this process (e.g. brines), are generally discharged directly into the coastal ecosystem, causing detrimental effects, on benthic organisms. Understanding the cellular stress response of these organisms (biomarkers), could be crucial for establishing appropriate salinity thresholds for discharged brines. Early stress biomarkers can serve as valuable tools for monitoring the health status of brine-impacted organisms, enabling the prediction of long-term irreversible damage caused by the desalination industry. In this study, we conducted laboratory-controlled experiments to assess cellular and molecular biomarkers against brine exposure in two salinity-sensitive Mediterranean seagrasses: Posidonia oceanica and Cymodocea nodosa. Treatments involved exposure to 39, 41, and 43 psu, for 6 h and 7 days. Results indicated that photosynthetic performance remained unaffected across all treatments. However, under 43 psu, P. oceanica and C. nodosa exhibited lipid oxidative damage, which occurred earlier in P. oceanica. Additionally, P. oceanica displayed an antioxidant response at higher salinities by accumulating phenolic compounds within 6 h and ascorbate within 7 d; whereas for C. nodosa the predominant antioxidant mechanisms were phenolic compounds accumulation and total radical scavenging activity, which was evident after 7 d of brines exposure. Finally, transcriptomic analyses in P. oceanica exposed to 43 psu for 7 days revealed a poor up-regulation of genes associated with brassinosteroid response and abiotic stress response, while a high down-regulation of genes related to primary metabolism was detected. In C. nodosa, up-regulated genes were involved in DNA repair, cell cycle regulation, and reproduction, while down-regulated genes were mainly associated with photosynthesis and ribosome assembly. Overall, these findings suggest that 43 psu is a critical salinity-damage threshold for both seagrasses; and despite the moderate overexpression of several transcripts that could confer salt tolerance, genes involved in essential biological processes were severely downregulated.FRR was financed by Fondecyt #11220425 grant from ANID, Chile. CAS was financed by project ANID InES I + D 2021 (INID210013) and by Marie Skłodowska-Curie Action (888415). FBM was supported by a grant from Universidad de Alicante (Grant ID: FPUUA98)

La historia de la voz

La voz humana fue definida por Platón como un impacto del aire que llega por los oídos al alma. La voz es el sustrato en el que se apoya el método de comunicación habitual del ser humano, con el que se transmite la cultura, con el que se expresan los sentimientos y las emociones. Por su cotidianidad muchas veces pasa desapercibida su extraordinaria importancia, sin embargo por su carácter específico y exclusivamente humano ha sido estudiado desde los inicios de nuestra civilización. Se revisan las aportaciones de los estudiosos en las principales épocas, sobre todo a partir del siglo XVI con los estudios de disección anatómica sobre laringes de carácter humano. Una época de extraordinaria importancia fue el siglo XVII donde los trabajos de Dodart y Perrault supusieron la base para que en el siglo siguiente Ferrein iniciara la fisiología experimental de la laringe. Mención especial merece Johanes Müller cuyos experimentos permitirán establecer las teorías de la fonación vigentes hoy día