Quiescent and coherent cores from gravoturbulent fragmentation

[abridged] We investigate the velocity structure of protostellar cores that result from non-magnetic numerical models of the gravoturbulent fragmentation of molecular cloud material. A large fraction of the cores analyzed are ``quiescent'', and more than half are identified as ``coherent''. The fact that dynamically evolving cores in highly supersonic turbulent flows can be quiescent may be understood because cores lie at the stagnation points of convergent turbulent flows, where compression is at a maximum, and relative velocity differences are at a minimum. The coherence may be due to an observational effect related to the length and concentration of the material contributing to the line. The velocity dispersion of the our cores often has its local maximum at small offsets from the column density maximum, suggesting that the core is the dense region behind a shock. Such a configuration is often found in observations of molecular cloud cores, and argues in favor of the gravoturbulent scenario of stellar birth as it is not expected in star-formation models based on magnetic mediation. Cores with collapsed objects tend to be near equipartition between their gravitational and kinetic energies, while cores without collapsed objects tend to be gravitationally unbound, suggesting that gravitational collapse occurs immediately after gravity becomes dominant. Finally, cores in simulations driven at large scales are more frequently quiescent and coherent, and have more realistic ratios of $M_{\rm vir}/M$, supporting the notion that molecular cloud turbulence is driven at large scales.Comment: ApJ, in pres

JULES-BE:Representation of bioenergy crops and harvesting in the Joint UK Land Environment Simulator vn5.1

We describe developments to the land surface model JULES, allowing for flexible user-prescribed harvest regimes of various perennial bioenergy crops or natural vegetation types. Our aim is to integrate the most useful aspects of dedicated bioenergy models into dynamic global vegetation models, in order that assessment of bioenergy options can benefit from state-of-the-art Earth system modelling. A new plant functional type (PFT) representing Miscanthus is also presented. The Miscanthus PFT fits well with growth parameters observed at a site in Lincolnshire, UK; however, global observed yields of Miscanthus are far more variable than is captured by the model, primarily owing to the model's lack of representation of crop age and establishment time. Global expansion of bioenergy crop areas under a 2 ?C emissions scenario and balanced greenhouse gas mitigation strategy from the IMAGE integrated assessment model (RCP2.6- SSP2) achieves a mean yield of 4.3 billion tonnes of dry matter per year over 2040-2099, around 30 % higher than the biomass availability projected by IMAGE. In addition to perennial grasses, JULES-BE can also be used to represent short-rotation coppicing, residue harvesting from cropland or forestry and rotation forestry

La imagen y la narrativa como instrumentos de la acción psicosocial en escenarios de violencia. Departamento del Meta

Los impactos o efectos que deja el conflicto armado hacen necesario que haya una comprensión desde una perspectiva psicosocial, en la que se profundice las diferentes variables que surgen dentro de los escenarios de violencia. Entre ellas, los relatos, las imágenes, las dinámicas sociales y los elementos simbólicos que han sido construidos desde los lugares y por las personas víctimas de estos flagelos. Desde el presente se hace un análisis a partir de eventos o situaciones traumáticas sufridas durante la violencia en nuestro país, procurando examinar y estudiar desde una visión como futuros psicólogos, estableciendo una posición concreta y congruente con el marco teórico y metodológico que promueve lo psicosocial. Se emplea así un análisis reflexivo al relato de Alfredo Campos, a través de una serie de interrogantes se debate y de manera colaborativa se reconocen aspectos subjetivos, impactos psicosociales, efectos de la violencia, posturas resilientes, y se formulan también preguntas circulares, reflexivas y estratégicas que permiten hacer un acercamiento al caso. Se aborda una propuesta desde lo psicosocial sustentada desde el enfoque narrativo Michael White (2003), donde a través del caso Peñas Coloradas se aborda una reflexión teniendo en cuenta ciertos ítems sobre el caso, entre estas las acciones y estrategias en la situación de crisis presentada. Por tanto, se hace construcción del producto final con los insumos logrados por el grupo. La interpretación de los casos relatados sobre el conflicto armado y sus consecuencias permiten ver episodios desde un punto de vista analítico y reflexivo del dolor; los abusos, calumnias, miedos, violencia, muertes, asesinatos, secuestros, que están sometidos a vivir y a huir.The impacts or effects left by the armed conflict make it necessary to have an understanding from a psychosocial perspective, in which the different variables that arise within the scenarios of violence are studied. Among them, the stories, images, social dynamics, and symbolic elements that have been constructed from the places and by the people who have been victims of these scourges. From the present, an analysis is made from events or traumatic situations suffered during the violence in our country, trying to examine and study from a vision as future psychologists, establishing a concrete and congruent position with the theoretical and methodological framework that promotes the psychosocial. A reflective analysis of Alfredo Campos' story is thus employed, through a series of questions and debates, and in a collaborative manner, subjective aspects, psychosocial impacts, effects of violence, resilient postures, and circular, reflective, and strategic questions are also formulated that allow for an approach to the case. A psychosocial approach based on the narrative approach of Michael White (2003), where through the Peñas Coloradas case, a reflection is approached taking into account certain items about the case, among these the actions and strategies in the crisis situation presented. Therefore, the final product is constructed with the inputs obtained by the group. The interpretation of the cases related to the armed conflict and its consequences allows to see episodes from an analytical and reflective point of view of the pain; the abuses, slander, fears, violence, deaths, murders, kidnappings, which they are subjected to live and flee

Vegetation distribution and terrestrial carbon cycle in a carbon cycle configuration of JULES4.6 with new plant functional types

Dynamic global vegetation models (DGVMs) are used for studying historical and future changes to vegetation and the terrestrial carbon cycle. JULES (the Joint UK Land Environment Simulator) represents the land surface in the Hadley Centre climate models and in the UK Earth System Model. Recently the number of plant functional types (PFTs) in JULES was expanded from five to nine to better represent functional diversity in global ecosystems. Here we introduce a more mechanistic representation of vegetation dynamics in TRIFFID, the dynamic vegetation component of JULES, which allows for any number of PFTs to compete based solely on their height; therefore, the previous hardwired dominance hierarchy is removed. With the new set of nine PFTs, JULES is able to more accurately reproduce global vegetation distribution compared to the former five PFT version. Improvements include the coverage of trees within tropical and boreal forests and a reduction in shrubs, the latter of which dominated at high latitudes. We show that JULES is able to realistically represent several aspects of the global carbon (C) cycle. The simulated gross primary productivity (GPP) is within the range of observations, but simulated net primary productivity (NPP) is slightly too high. GPP in JULES from 1982 to 2011 is 133PgCyr−1, compared to observation-based estimates (over the same time period) between 123±8 and 150–175PgCyr−1. NPP from 2000 to 2013 is 72PgCyr−1, compared to satellite-derived NPP of 55PgCyr−1 over the same period and independent estimates of 56.2±14.3PgCyr−1. The simulated carbon stored in vegetation is 542PgC, compared to an observation-based range of 400–600PgC. Soil carbon is much lower (1422PgC) than estimates from measurements ( > 2400PgC), with large underestimations of soil carbon in the tropical and boreal forests. We also examined some aspects of the historical terrestrial carbon sink as simulated by JULES. Between the 1900s and 2000s, increased atmospheric carbon dioxide levels enhanced vegetation productivity and litter inputs into the soils, while land use change removed vegetation and reduced soil carbon. The result is a simulated increase in soil carbon of 57PgC but a decrease in vegetation carbon of 98PgC. The total simulated loss of soil and vegetation carbon due to land use change is 138PgC from 1900 to 2009, compared to a recent observationally constrained estimate of 155±50PgC from 1901 to 2012. The simulated land carbon sink is 2.0±1.0PgCyr−1 from 2000 to 2009, in close agreement with estimates from the IPCC and Global Carbon Project

Implementation of trait-based ozone plant sensitivity in the Yale interactive terrestrial biosphere model v1.0 to assess global vegetation damage

A major limitation in modeling global ozone (O3) vegetation damage has long been the reliance on empiri- cal O3 sensitivity parameters derived from a limited num- ber of species and applied at the level of plant functional types (PFTs), which ignore the large interspecific variations within the same PFT. Here, we present a major advance in large-scale assessments of O3 plant injury by linking the trait leaf mass per area (LMA) and plant O3 sensitivity in a broad and global perspective. Application of the new ap- proach and a global LMA map in a dynamic global veg- etation model reasonably represents the observed interspe- cific responses to O3 with a unified sensitivity parameter for all plant species. Simulations suggest a contemporary global mean reduction of 4.8 % in gross primary productivity by O3, with a range of 1.1 %–12.6 % for varied PFTs. Hotspots with damage > 10 % are found in agricultural areas in the eastern US, western Europe, eastern China, and India, accompanied by moderate to high levels of surface O3. Furthermore, we simulate the distribution of plant sensitivity to O3, which is highly linked with the inherent leaf trait trade-off strategies of plants, revealing high risks for fast-growing species with low LMA, such as crops, grasses, and deciduous trees

Modeled microbial dynamics explain the apparent temperature sensitivity of wetland methane emissions

Methane emissions from natural wetlands tend to increase with temperature and therefore may lead to a positive feedback under future climate change. However, their temperature response includes confounding factors and appears to differ on different time scales. Observed methane emissions depend strongly on temperature on a seasonal basis, but if the annual mean emissions are compared between sites, there is only a small temperature effect. We hypothesize that microbial dynamics are a major driver of the seasonal cycle and that they can explain this apparent discrepancy. We introduce a relatively simple model of methanogenic growth and dormancy into a wetland methane scheme that is used in an Earth system model. We show that this addition is sufficient to reproduce the observed seasonal dynamics of methane emissions in fully saturated wetland sites, at the same time as reproducing the annual mean emissions. We find that a more complex scheme used in recent Earth system models does not add predictive power. The sites used span a range of climatic conditions, with the majority in high latitudes. The difference in apparent temperature sensitivity seasonally versus spatially cannot be recreated by the non‐microbial schemes tested. We therefore conclude that microbial dynamics are a strong candidate to be driving the seasonal cycle of wetland methane emissions. We quantify longer‐term temperature sensitivity using this scheme and show that it gives approximately a 12% increase in emissions per degree of warming globally. This is in addition to any hydrological changes, which could also impact future methane emissions

Post-intervention Status in Patients With Refractory Myasthenia Gravis Treated With Eculizumab During REGAIN and Its Open-Label Extension

OBJECTIVE: To evaluate whether eculizumab helps patients with anti-acetylcholine receptor-positive (AChR+) refractory generalized myasthenia gravis (gMG) achieve the Myasthenia Gravis Foundation of America (MGFA) post-intervention status of minimal manifestations (MM), we assessed patients' status throughout REGAIN (Safety and Efficacy of Eculizumab in AChR+ Refractory Generalized Myasthenia Gravis) and its open-label extension. METHODS: Patients who completed the REGAIN randomized controlled trial and continued into the open-label extension were included in this tertiary endpoint analysis. Patients were assessed for the MGFA post-intervention status of improved, unchanged, worse, MM, and pharmacologic remission at defined time points during REGAIN and through week 130 of the open-label study. RESULTS: A total of 117 patients completed REGAIN and continued into the open-label study (eculizumab/eculizumab: 56; placebo/eculizumab: 61). At week 26 of REGAIN, more eculizumab-treated patients than placebo-treated patients achieved a status of improved (60.7% vs 41.7%) or MM (25.0% vs 13.3%; common OR: 2.3; 95% CI: 1.1-4.5). After 130 weeks of eculizumab treatment, 88.0% of patients achieved improved status and 57.3% of patients achieved MM status. The safety profile of eculizumab was consistent with its known profile and no new safety signals were detected. CONCLUSION: Eculizumab led to rapid and sustained achievement of MM in patients with AChR+ refractory gMG. These findings support the use of eculizumab in this previously difficult-to-treat patient population. CLINICALTRIALSGOV IDENTIFIER: REGAIN, NCT01997229; REGAIN open-label extension, NCT02301624. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that, after 26 weeks of eculizumab treatment, 25.0% of adults with AChR+ refractory gMG achieved MM, compared with 13.3% who received placebo

Minimal Symptom Expression' in Patients With Acetylcholine Receptor Antibody-Positive Refractory Generalized Myasthenia Gravis Treated With Eculizumab

The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase 3, randomized, double-blind, placebo-controlled study in anti-acetylcholine receptor antibody-positive (AChR+) refractory generalized myasthenia gravis (gMG), and its open-label extension