Quantitative studies of the evolution and cosmological consequences of networks of cosmic strings (or other topological defects) require a combination of numerical simulations and analytic modeling ...with the velocity-dependent one-scale (VOS) model. In previous work, we demonstrated that a GPU-accelerated code for local Abelian-Higgs string networks enables a statistical separation of key dynamical processes affecting the evolution of the string networks and thus a precise calibration of the VOS model. Here we further exploit this code in a detailed study of two important aspects connecting the simulations with the VOS model. First, we study the sensitivity of the model calibration to the presence (or absence) of thermal oscillations due to high gradients in the initial conditions. This is relevant since in some Abelian-Higgs simulations described in the literature a period of artificial (unphysical) dissipation-usually known as cooling-is introduced with the goal of suppressing these oscillations and accelerating the convergence to scaling. We show that a small amount of cooling has no statistically significant impact on the VOS model calibration, while a longer dissipation period does have a noticeable effect. Second, in doing this analysis we also introduce an improved Markov Chain Monte Carlo based pipeline for calibrating the VOS model, Comparison to our previous bootstrap based pipeline shows that the latter accurately determined the best-fit values of the VOS model parameter, but underestimated the uncertainties in some of the parameters. Overall, our analysis shows that the calibration pipeline is robust and can be applied to future much larger field theory simulations.
Understanding the evolution and cosmological consequences of topological defect networks requires a combination of analytic modeling and numerical simulations. The canonical analytic model for defect ...network evolution is the velocity-dependent one-scale (VOS) model. For the case of cosmic strings, this has so far been calibrated using small numbers of Goto-Nambu and field theory simulations, in the radiation and matter eras as well as in Minkowski spacetime. But the model is only as good as the available simulations, and it should be extended as further simulations become available. In previous work, we presented a general purpose graphics processing unit implementation of the evolution of cosmological domain wall networks and used it to obtain an improved VOS model for domain walls. Here, we continue this effort, exploiting a more recent analogous code for local Abelian-Higgs string networks. The significant gains in speed afforded by this code enabled us to carry out 1032 field theory simulations of 5123 size, with 43 different expansion rates. This detailed exploration of the effects of the expansion rate on the network properties in turn enables a statistical separation of various dynamical processes affecting the evolution of the network. We thus extend and accurately calibrate the VOS model for cosmic strings, including separate terms for energy losses due to loop production and scalar/gauge radiation. By comparing this newly calibrated VOS model with the analogous one for domain walls, we quantitatively show that energy loss mechanisms are different for the two types of defects.
Domain walls form at phase transitions which break discrete symmetries. In a cosmological context, they often overclose the Universe (contrary to observational evidence), although one may prevent ...this by introducing biases or forcing anisotropic evolution of the walls. In a previous work Correia et al., Phys. Rev. D 90, 023521 (2014), we numerically studied the evolution of various types of biased domain wall networks in the early Universe, confirming that anisotropic networks ultimately reach scaling while those with a biased potential or biased initial conditions decay. We also found that the analytic decay law obtained by Hindmarsh was in good agreement with simulations of biased potentials, but not of biased initial conditions, and suggested that the difference was related to the Gaussian approximation underlying the analytic law. Here, we extend our previous work in several ways. For the cases of biased potential and biased initial conditions, we study in detail the field distributions in the simulations, confirming that the validity (or not) of the Gaussian approximation is the key difference between the two cases. For anisotropic walls, we carry out a more extensive set of numerical simulations and compare them to the canonical velocity-dependent one-scale model for domain walls, finding that the model accurately predicts the linear scaling regime after isotropization. Overall, our analysis provides a quantitative description of the cosmological evolution of these networks.
Feedbacks between land carbon pools and climate provide one of the largest sources of uncertainty in our predictions of global climate. Estimates of the sensitivity of the terrestrial carbon budget ...to climate anomalies in the tropics and the identification of the mechanisms responsible for feedback effects remain uncertain. The Amazon basin stores a vast amount of carbon, and has experienced increasingly higher temperatures and more frequent floods and droughts over the past two decades. Here we report seasonal and annual carbon balances across the Amazon basin, based on carbon dioxide and carbon monoxide measurements for the anomalously dry and wet years 2010 and 2011, respectively. We find that the Amazon basin lost 0.48 ± 0.18 petagrams of carbon per year (Pg C yr(-1)) during the dry year but was carbon neutral (0.06 ± 0.1 Pg C yr(-1)) during the wet year. Taking into account carbon losses from fire by using carbon monoxide measurements, we derived the basin net biome exchange (that is, the carbon flux between the non-burned forest and the atmosphere) revealing that during the dry year, vegetation was carbon neutral. During the wet year, vegetation was a net carbon sink of 0.25 ± 0.14 Pg C yr(-1), which is roughly consistent with the mean long-term intact-forest biomass sink of 0.39 ± 0.10 Pg C yr(-1) previously estimated from forest censuses. Observations from Amazonian forest plots suggest the suppression of photosynthesis during drought as the primary cause for the 2010 sink neutralization. Overall, our results suggest that moisture has an important role in determining the Amazonian carbon balance. If the recent trend of increasing precipitation extremes persists, the Amazon may become an increasing carbon source as a result of both emissions from fires and the suppression of net biome exchange by drought.
Atrophic gastritis, intestinal metaplasia, and epithelial dysplasia of the stomach are common and are associated with an increased risk for gastric cancer. In the absence of guidelines, there is wide ...disparity in the management of patients with these premalignant conditions. The European Society of Gastrointestinal Endoscopy (ESGE), the European Helicobacter Study Group (EHSG), the European Society of Pathology (ESP) and the Sociedade Portuguesa de Endoscopia Digestiva (SPED) have therefore combined efforts to develop evidence-based guidelines on the management of patients with precancerous conditions and lesions of the stomach (termed MAPS). A multidisciplinary group of 63 experts from 24 countries developed these recommendations by means of repeat online voting and a meeting in June 2011 in Porto, Portugal. The recommendations emphasize the increased cancer risk in patients with gastric atrophy and metaplasia, and the need for adequate staging in the case of high grade dysplasia, and they focus on treatment and surveillance indications and methods.
Summary Background A lack of agreement on definitions and terminology used for nutrition-related concepts and procedures limits the development of clinical nutrition practice and research. Objective ...This initiative aimed to reach a consensus for terminology for core nutritional concepts and procedures. Methods The European Society of Clinical Nutrition and Metabolism (ESPEN) appointed a consensus group of clinical scientists to perform a modified Delphi process that encompassed e-mail communication, face-to-face meetings, in-group ballots and an electronic ESPEN membership Delphi round. Results Five key areas related to clinical nutrition were identified: concepts; procedures; organisation; delivery; and products. One core concept of clinical nutrition is malnutrition/undernutrition, which includes disease-related malnutrition (DRM) with (eq. cachexia) and without inflammation, and malnutrition/undernutrition without disease, e.g. hunger-related malnutrition. Over-nutrition (overweight and obesity) is another core concept. Sarcopenia and frailty were agreed to be separate conditions often associated with malnutrition. Examples of nutritional procedures identified include screening for subjects at nutritional risk followed by a complete nutritional assessment. Hospital and care facility catering are the basic organizational forms for providing nutrition. Oral nutritional supplementation is the preferred way of nutrition therapy but if inadequate then other forms of medical nutrition therapy, i.e. enteral tube feeding and parenteral (intravenous) nutrition, becomes the major way of nutrient delivery. Conclusion An agreement of basic nutritional terminology to be used in clinical practice, research, and the ESPEN guideline developments has been established. This terminology consensus may help to support future global consensus efforts and updates of classification systems such as the International Classification of Disease (ICD). The continuous growth of knowledge in all areas addressed in this statement will provide the foundation for future revisions.
Two major droughts in the past decade had large impacts on carbon exchange in the Amazon. Recent analysis of vertical profile measurements of atmospheric CO2 and CO by Gatti et al. (2014) suggests ...that the 2010 drought turned the normally close‐to‐neutral annual Amazon carbon balance into a substantial source of nearly 0.5 PgC/yr, revealing a strong drought response. In this study, we revisit this hypothesis and interpret not only the same CO2/CO vertical profile measurements but also additional constraints on carbon exchange such as satellite observations of CO, burned area, and fire hot spots. The results from our CarbonTracker South America data assimilation system suggest that carbon uptake by vegetation was indeed reduced in 2010 but that the magnitude of the decrease strongly depends on the estimated 2010 and 2011 biomass burning emissions. We have used fire products based on burned area (Global Fire Emissions Database version 4), satellite‐observed CO columns (Infrared Atmospheric Sounding Interferometer), fire radiative power (Global Fire Assimilation System version 1), and fire hot spots (Fire Inventory from NCAR version 1), and found an increase in biomass burning emissions in 2010 compared to 2011 of 0.16 to 0.24 PgC/yr. We derived a decrease of biospheric uptake ranging from 0.08 to 0.26 PgC/yr, with the range determined from a set of alternative inversions using different biomass burning estimates. Our numerical analysis of the 2010 Amazon drought results in a total reduction of carbon uptake of 0.24 to 0.50 PgC/yr and turns the balance from carbon sink to source. Our findings support the suggestion that the hydrological cycle will be an important driver of future changes in Amazonian carbon exchange.
Key Points
Amazon carbon budget estimated by CarbonTracker South America
Biospheric uptake decreases by 0.08–0.26 PgC/yr in response to 2010 drought
Amazon biomass burning emissions more than doubled during 2010 drought
This initiative is focused on building a global consensus around core diagnostic criteria for malnutrition in adults in clinical settings.
In January 2016, the Global Leadership Initiative on ...Malnutrition (GLIM) was convened by several of the major global clinical nutrition societies. GLIM appointed a core leadership committee and a supporting working group with representatives bringing additional global diversity and expertise. Empirical consensus was reached through a series of face-to-face meetings, telephone conferences, and e-mail communications.
A two-step approach for the malnutrition diagnosis was selected, i.e., first screening to identify “at risk” status by the use of any validated screening tool, and second, assessment for diagnosis and grading the severity of malnutrition. The malnutrition criteria for consideration were retrieved from existing approaches for screening and assessment. Potential criteria were subjected to a ballot among the GLIM core and supporting working group members. The top five ranked criteria included three phenotypic criteria (non-volitional weight loss, low body mass index, and reduced muscle mass) and two etiologic criteria (reduced food intake or assimilation, and inflammation or disease burden). To diagnose malnutrition at least one phenotypic criterion and one etiologic criterion should be present. Phenotypic metrics for grading severity as Stage 1 (moderate) and Stage 2 (severe) malnutrition are proposed. It is recommended that the etiologic criteria be used to guide intervention and anticipated outcomes. The recommended approach supports classification of malnutrition into four etiology-related diagnosis categories.
A consensus scheme for diagnosing malnutrition in adults in clinical settings on a global scale is proposed. Next steps are to secure further collaboration and endorsements from leading nutrition professional societies, to identify overlaps with syndromes like cachexia and sarcopenia, and to promote dissemination, validation studies, and feedback. The diagnostic construct should be re-considered every 3–5 years.
Hereby, a precisely controlled one-step electrode modification is presented where the enzyme laccase is immobilized during the potentiostatic deposition of a thin polydopamine film (ePDA) on carbon ...surfaces. The morphology, wettability, optical and electrochemical properties of the modified electrodes were accessed by atomic force microscopy, water contact angle goniometry, ellipsometry and cyclic voltammetry. The results indicate that laccase is robustly immobilized and evenly distributed in the ePDA matrix, not significantly affecting the redox behavior of the polymer. The catalytic activity of the laccase-polymer modified electrodes is confirmed by chronoamperometry for 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) detection, a well-known substrate of laccase. The proposed fast and efficient one-pot procedure is implemented on cheap disposable graphite electrodes, targeting the detection of phenolic compounds: caffeic acid, rosmarinic acid and gallic acid. The catalytic performance of the modified electrodes was evaluated in terms of reproducibility, sensitivity, limits of detection (LOD) and linear range. For gallic acid a calibration curve with a sensitivity of 19.3 mA M−1 cm−2, 1–150 μM linear range and a LOD of 0.29 μM is obtained, allowing the estimation of the low molecular weight phenols content in an extract of chestnut shell industrial waste.
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•Laccase robustly immobilized through one-step potentiostatic growth of polydopamine (ePDA).•Biocompatible ePDA films with evenly distributed laccase display high catalytic properties.•Disposable modified electrodes sensitively and reproducibly detect phenolic compounds.•Gallic acid content on a phenol-rich chestnut shell extract is estimated.
The canonical velocity-dependent one-scale (VOS) model for cosmic string evolution must be calibrated using high resolution numerical simulations, We exploit our state of the art graphics processing ...unit accelerated implementation of the evolution of local Abelian-Higgs string networks to provide a detailed and statistically robust calibration of the VOS model. We rely on the largest set of high resolution simulations carried out to date, with a wide range of cosmological expansion rates, and explore the impact of key numerical parameters, including the dynamic range (comparing box sizes from 10243 to 40963), the lattice spacing, and the choice of numerical estimators for the string velocity. We explore the sensitivity of the VOS model parameters to these numerical parameters, with a particular emphasis on the observationally crucial loop chopping efficiency, and also identify key differences between the equation of state and conjugate momentum estimators for the string velocities, showing that the latter one is more reliable for fast expansion rates (while in Minkowski space the opposite has been previously shown). Finally, we briefly illustrate how our results impact observational constraints on cosmic strings.
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