Modeling benzene plume elongation mechanisms exerted by ethanol using RT3D with a general substrate interaction module

Copyright © 2008 American Geophysical Union (AGU)A mathematical model was developed to evaluate the effect of the common fuel additive ethanol on benzene fate and transport in fuel-contaminated groundwater and to discern the most influential benzene plume elongation mechanisms. The model, developed as a module for the Reactive Transport in 3 Dimensions (RT3D) model, includes commonly considered fate and transport processes (advection, dispersion, adsorption, biodegradation, and depletion of molecular oxygen during biodegradation) and substrate interactions previously not considered (e.g., a decrease in the specific benzene utilization rate due to metabolic flux dilution and/or catabolite repression) as well as microbial population shifts. Benzene plume elongation predictions, based on literature model parameters, were on the order of 40% for a constant source of E10 gasoline (10% vol/vol ethanol), which compares favorably to field observations. For low benzene concentrations (<1 mg/L), oxygen depletion during ethanol degradation was the principal mechanism hindering benzene natural attenuation. For higher benzene concentrations (exerting an oxygen demand higher than the available dissolved oxygen), metabolic flux dilution was the dominant plume elongation process. If oxygen were not limiting, as might be the case in zones undergoing aerobic biostimulation, model simulations showed that microbial growth on ethanol could offset negative substrate interactions and enhance benzene degradation, resulting in shorter plumes than baseline conditions without ethanol

Genotype determines Arbutus unedo L. physiological and metabolomic responses to drought and recovery

Strawberry tree (Arbutus unedo) is a small resilient species with a circum-Mediterranean distribution, high ecological relevance in southern European forests and with several economical applications. As most orchards are usually installed on marginal lands where plants usually face severe drought, selecting plants that can better cope with water restriction is critical, and a better understanding of the tolerance mechanisms is required. Strawberry tree plants under drought follow a typical isohydric strategy, by limiting transpiration through stomata closure. However, the contribution of genotype and its bio-geographic origin on plant performance needs clarification, as well as the involvement of a specific metabolic reactions associated with the mechanical response. To test this hypothesis, several eco-physiological and biochemical parameters were assessed on different genotypes, and the metabolic profiles studied, including important stress-related phytohormones, on plants under different water regimes (plants watered to 70% and 18% field capacity) and a recovery assay. A contrasting drought tolerance was found in plants from different genotypes, associated with physiological and metabolic responses. Metabolomics revealed more than 500 metabolic features were differentially accumulated, including abscisic and salicylic acids, for the genotype with better performance under drought (A4). This genotype also recovered faster when the imposed stress was interrupted, thus indicating the relevance of metabolic adaptation under water deficit conditions. By correlating carbon assimilation with identified metabolites, some proved to be satisfactory predictors of plant performance under drought and might be used for marker assisted breeding. Therefore, our study proves the importance of genotype as a major selection criterion of resistant plants to drought and provides empirical knowledge of the metabolic response involved. We also hypothesized the involvement of phenolics on response mechanisms under drought, which is worth to be explored to shed light on the metabolic pathways involved in plant response to water stress

The Port service area project, Santander: Central state and local authority intervention in the planning and development of a port-side industrial zone

This article reports on a case study research project that examines the planning and development of a port-side industrial zone in the Franco era in Santander, Spain. The case study illustrates some key features of central and local authority intervention in the area, which may be of value and interest to planners and politicians working in similar politico-administrative environments. The study concludes that, as regards plan implementation, the development of the Port Service Area involved contravention of the statutory approved urban plan for the area and irregularities in planning procedure. Despite these shortcomings, the development of the Port Service Area has been an economic and strategic success

Primer registro de Serratospiculum tendo (Nematoda: Diplotriaenidae) para el Perú

We report for first time the presence of nematode, Serratospiculum tendo Nitzsch, 1819, parasitizing air sacs of a Peregrine Falcon (Falco peregrinus Tunstall, 1771). Six nematodes (2 males and 4 females) were collected and identified as S. tendo. The discovery of this nematode is the first record in Peru.Reportamos por primera vez la presencia del nematodo, Serratospiculum tendo Nitzsch, 1819, parasitando los sacos aéreos de un halcón peregrino (Falco peregrinus Tunstall, 1771). Seis nematodos (2 machos y 4 hembras) fueron colectados e identificados como S. tendo. El hallazgo de este nematodo constituye el primer registro en el Perú

Adaptation, reliability and validity of a Brief Multicomponent AIDS Phobia Scale (MAPS) in Colombian adolescents

La fobia al sida consiste en un miedo persistente, anormal e injustificado a contraer el VIH. Uno de los instrumentos disponibles para evaluar la fobia al sida es la Multicomponent AIDS Phobia Scale (MAPS). El objetivo de este estudio fue adaptar y validar la MAPS en adolescentes colombianos. Participaron 859 estudiantes entre 14-19 años respondiendo a la MAPS y otros autoinformes para analizar su validez (conocimientos sobre las ITS, actitud hacia el VIH y ansiedad por la salud). El análisis factorial confirmó la estructura bifactorial (F1: miedo a la infección y F2: miedo a otros), de acuerdo con la versión original. Se obtuvo evidencias de fiabilidad y validez consistentes con la teoría. La aplicación de la MAPS es idónea para evaluar miedo al VIH/sida y estudiar su relación con factores de riesgo sexual (uso de condón, múltiples parejas sexuales) a nivel investigador y comunitario en Colombia. También puede ser útil para evaluar el impacto de campañas sociales para reducir el estigma hacia el VIH y programas de prevención dirigidos a promover una sexualidad saludable en adolescentes mediante la transmisión de conocimientos adecuados y actitudes más tolerantes hacia las personas que viven con VIH.The AIDS phobia is a persistent, abnormal and unjustified fear of contracting HIV. The objective of this study was to adapt and validate MAPS in Colombian adolescents. Participants included 856 students aged 14-19 years who responded to the MAPS and other self-reports to analyze its validity (including knowledge about STIs, attitude towards HIV and health anxiety). Factor analysis confirmed the bifactorial structure (F1: fear of infection and F2: fear of others), according to the original version. Evidence of reliability and validity was obtained consistently with the theory. The application of MAPS is appropriate for assessing fear of HIV/AIDS and to study its relationship with sexual risk factors (e.g. condom use, multiple sexual partners) at research and community levels in Colombia. It also can be useful for assessing the impact of social campaigns to reduce stigma towards HIV and prevention programs aimed at promoting healthy sexuality in adolescents through the transmission of adequate knowledge and more favorable attitudes toward people living with HI

Fructose consumption reduces hippocampal synaptic plasticity underlying cognitive performance

AbstractMetabolic syndrome (MetS) is a global epidemic, which involves a spectrum of metabolic disorders comprising diabetes and obesity. The impact of MetS on the brain is becoming to be a concern, however, the poor understanding of mechanisms involved has limited the development of therapeutic strategies. We induced a MetS-like condition by exposing mice to fructose feeding for 7weeks. There was a dramatic deterioration in the capacity of the hippocampus to sustain synaptic plasticity in the forms of long-term potentiation (LTP) and long-term depression (LTD). Mice exposed to fructose showed a reduction in the number of contact zones and the size of postsynaptic densities (PSDs) in the hippocampus, as well as a decrease in hippocampal neurogenesis. There was an increase in lipid peroxidation likely associated with a deficiency in plasma membrane excitability. Consistent with an overall hippocampal dysfunction, there was a subsequent decrease in hippocampal dependent learning and memory performance, i.e., spatial learning and episodic memory. Most of the pathological sequel of MetS in the brain was reversed three month after discontinue fructose feeding. These results are novel to show that MetS triggers a cascade of molecular events, which disrupt hippocampal functional plasticity, and specific aspects of learning and memory function. The overall information raises concerns about the risk imposed by excessive fructose consumption on the pathology of neurological disorders

Real-time camera motion tracking in planar view scenarios

We propose a novel method for real-time camera motion tracking in planar view scenarios. This method relies on the geometry of a tripod, an initial estimation of camera pose for the first video frame and a primitive tracking procedure. This process uses lines and circles as primitives, which are extracted applying classification and regression tree. We have applied the proposed method to high-definition videos of soccer matches. Experimental results prove that our proposal can be applied to processing high-definition video in real time. We validate the procedure by inserting virtual content in the video sequence

Grazing Collisions of Black Holes via the Excision of Singularities

We present the first simulations of non-headon (grazing) collisions of binary black holes in which the black hole singularities have been excised from the computational domain. Initially two equal mass black holes $m$ are separated a distance $\approx10m$ and with impact parameter $\approx2m$. Initial data are based on superposed, boosted (velocity $\approx0.5c$) solutions of single black holes in Kerr-Schild coordinates. Both rotating and non-rotating black holes are considered. The excised regions containing the singularities are specified by following the dynamics of apparent horizons. Evolutions of up to $t \approx 35m$ are obtained in which two initially separate apparent horizons are present for $t\approx3.8m$. At that time a single enveloping apparent horizon forms, indicating that the holes have merged. Apparent horizon area estimates suggest gravitational radiation of about 2.6% of the total mass. The evolutions end after a moderate amount of time because of instabilities.Comment: 2 References corrected, reference to figure update

Intensive care unit discharge to the ward with a tracheostomy cannula as a risk factor for mortality: A prospective, multicenter propensity analysis

To analyze the impact of decannulation before intensive care unit discharge on ward survival in nonexperimental conditions. DESIGN: Prospective, observational survey. SETTING: Thirty-one intensive care units throughout Spain. PATIENTS: All patients admitted from March 1, 2008 to May 31, 2008. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: At intensive care unit discharge, we recorded demographic variables, severity score, and intensive care unit treatments, with special attention to tracheostomy. After intensive care unit discharge, we recorded intensive care unit readmission and hospital survival. STATISTICS: Multivariate analyses for ward mortality, with Cox proportional hazard ratio adjusted for propensity score for intensive care unit decannulation. We included 4,132 patients, 1,996 of whom needed mechanical ventilation. Of these, 260 (13%) were tracheostomized and 59 (23%) died in the intensive care unit. Of the 201 intensive care unit tracheostomized survivors, 60 were decannulated in the intensive care unit and 141 were discharged to the ward with cannulae in place. Variables associated with intensive care unit decannulation (non-neurologic disease [85% vs. 64%], vasoactive drugs [90% vs. 76%], parenteral nutrition [55% vs. 33%], acute renal failure [37% vs. 23%], and good prognosis at intensive care unit discharge [40% vs. 18%]) were included in a propensity score model for decannulation. Crude ward mortality was similar in decannulated and nondecannulated patients (22% vs. 23%); however, after adjustment for the propensity score and Sabadell Score, the presence of a tracheostomy cannula was not associated with any survival disadvantage with an odds ratio of 0.6 [0.3-1.2] (p=.1). CONCLUSION: In our multicenter setting, intensive care unit discharge before decannulation is not a risk factor

Circadian rhythms have significant effects on leaf-to-canopy scale gas exchange under field conditions

Background Molecular clocks drive oscillations in leaf photosynthesis, stomatal conductance, and other cell and leaf-level processes over ~24 h under controlled laboratory conditions. The influence of such circadian regulation over whole-canopy fluxes remains uncertain; diurnal CO2 and H2O vapor flux dynamics in the field are currently interpreted as resulting almost exclusively from direct physiological responses to variations in light, temperature and other environmental factors. We tested whether circadian regulation would affect plant and canopy gas exchange at the Montpellier European Ecotron. Canopy and leaf-level fluxes were constantly monitored under field-like environmental conditions, and under constant environmental conditions (no variation in temperature, radiation, or other environmental cues). Results We show direct experimental evidence at canopy scales of the circadian regulation of daytime gas exchange: 20–79 % of the daily variation range in CO2 and H2O fluxes occurred under circadian entrainment in canopies of an annual herb (bean) and of a perennial shrub (cotton). We also observed that considering circadian regulation improved performance by 8–17 % in commonly used stomatal conductance models. Conclusions Our results show that circadian controls affect diurnal CO2 and H2O flux patterns in entire canopies in field-like conditions, and its consideration significantly improves model performance. Circadian controls act as a ‘memory’ of the past conditions experienced by the plant, which synchronizes metabolism across entire plant canopies