Symplectic torus actions with coisotropic principal orbits

In this paper we completely classify symplectic actions of a torus $T$ on a compact connected symplectic manifold $(M, \sigma)$ when some, hence every, principal orbit is a coisotropic submanifold of $(M, \sigma)$. That is, we construct an explicit model, defined in terms of certain invariants, of the manifold, the torus action and the symplectic form. The invariants are invariants of the topology of the manifold, of the torus action, or of the symplectic form. In order to deal with symplectic actions which are not Hamiltonian, we develop new techniques, extending the theory of Atiyah, Guillemin-Sternberg, Delzant, and Benoist. More specifically, we prove that there is a well-defined notion of constant vector fields on the orbit space $M/T$. Using a generalization of the Tietze-Nakajima theorem to what we call $V$-parallel spaces, we obtain that $M/T$ is isomorphic to the Cartesian product of a Delzant polytope with a torus. We then construct special lifts of the constant vector fields on $M/T$, in terms of which the model of the symplectic manifold with the torus action is defined

Moduli spaces of toric manifolds

We construct a distance on the moduli space of symplectic toric manifolds of dimension four. Then we study some basic topological properties of this space, in particular, path-connectedness, compactness, and completeness. The construction of the distance is related to the Duistermaat-Heckman measure and the Hausdorff metric. While the moduli space, its topology and metric, may be constructed in any dimension, the tools we use in the proofs are four-dimensional, and hence so is our main result.Comment: To appear in Geometriae Dedicata, minor changes to previous version, 19 pages, 6 figure

Scale-Up Methodology for Bench-Scale Slurry Photocatalytic Reactors Using Combined Irradiation and Kinetic Modelling

The present study focuses on developing a predictive methodology to scale-up a slurry annular photoreactor using a TiO2 Degussa P25 from the bench-scale to a pilot-plant scale. The bench-scale photoreactor is a Photo-CREC-Water II, a 2.65 L internally-irradiated slurry annular photocatalytic reactor. The pilot-plant scale photoreactor is a Photo-CREC Water Solar Simulator, a 9.8 L pilot-plant photoreactor, externally irradiated by eight lamps. The adopted methodology allows the independent validation of radiative and kinetic models avoiding cross-correlation issues. The proposed approach involves two Monte Carlo methods, to model the Radiative Transfer Equation (RTE) inside each photoreactor. With this end, a novel probe is developed to measure irradiance at different radial positions for improved RTE parameter estimation This allows determining both adequate boundary conditions in the photo-CREC-Water II unit as well as establishing a phase function for Degussa P25 TiO2. On the other hand, a kinetic model and kinetic parameters are established by carrying out photocatalytic degradations of a model pollutant (Oxalic Acid). Kinetic experiments are developed at different photocatalyst concentrations and various irradiance conditions. Additionally, convective and dispersive transport models are proposed and solved by Finite Element (FE) Method to determine the photocatalyst irradiation time in each photoreactor unit and ultimately to predict the overall photocatalytic efficiency. Finally the kinetic-irradiance based model is validated. This is done by predicting irradiance profiles and degradation rates at different photocatalyst concentrations and irradiance conditions on the larger Photo-CREC Water III (Photo CREC Water Solar Simulator) photoreactor

Hamiltonian dynamics and spectral theory for spin-oscillators

We study the Hamiltonian dynamics and spectral theory of spin-oscillators. Because of their rich structure, spin-oscillators display fairly general properties of integrable systems with two degrees of freedom. Spin-oscillators have infinitely many transversally elliptic singularities, exactly one elliptic-elliptic singularity and one focus-focus singularity. The most interesting dynamical features of integrable systems, and in particular of spin-oscillators, are encoded in their singularities. In the first part of the paper we study the symplectic dynamics around the focus-focus singularity. In the second part of the paper we quantize the coupled spin-oscillators systems and study their spectral theory. The paper combines techniques from semiclassical analysis with differential geometric methods.Comment: 32 page

Introduction to the special issue on high performance computing solutions for complex problems

[No abstract available

Assessing the effects of using high-quality data and high-resolution models in valuing flood protection services of mangroves

The rate of change on coastlines is accelerating from climate change and coastal development. Coastal flooding is a particularly pressing and increasing problem, which affects hundreds of millions of people and damages trillions of US$ in property. Scientists, practitioners and managers must be able to quickly assess flood risk and identify appropriate adaptation and risk reduction measures often with limited data and tools, particularly in developing countries. To inform these decision-making processes, we identify how sensitive flood risk and adaptation analyses are to changes in the resolution of data and models. We further do these comparisons in the context of assess the benefits of an ecosystem-based approach for risk reduction. There is growing interest in these ecosystem-based approaches as cost effective measures for adaptation and risk reduction. We assess flood risks from tropical cyclones and the flood risk reduction benefits provided by mangroves in Pagbilao (the Philippines). Then, we also compare risks and risk reduction (benefits) using different quality data and models, to identify where to invest in in new modeling and data acquisition to improve decision-making. We find that coastal flood risk valuation improves by using high resolution topography and long time series of data on tropical cyclones, while flood reduction benefits of mangroves are better valued by using consistent databases and models along the whole process rather than investing in single measures.We gratefully acknowledge support from the World Bank WAVES Program (Wealth Account- ing and the Valuation of Ecosystem Services) and by the Spanish Ministry of Economy and Innovation (currently named as Ministry of Science, Innovation and Universities), within ECOPROOF project (BIA2014-59718-R), RISKOADAPT project (BIA2017-89401-R) and the FPI grant (BES-2015-074343

Habitat segregation and ecological character displacement in cryptic African malaria mosquitoes

This is an open access article under the terms of the Creative Commons Attribution License.-- et al.Understanding how divergent selection generates adaptive phenotypic and population diversification provides a mechanistic explanation of speciation in recently separated species pairs. Towards this goal, we sought ecological gradients of divergence between the cryptic malaria vectors Anopheles coluzzii and An. gambiae and then looked for a physiological trait that may underlie such divergence. Using a large set of occurrence records and eco-geographic information, we built a distribution model to predict the predominance of the two species across their range of sympatry. Our model predicts two novel gradients along which the species segregate: distance from the coastline and altitude. Anopheles coluzzii showed a 'bimodal' distribution, predominating in xeric West African savannas and along the western coastal fringe of Africa. To test whether differences in salinity tolerance underlie this habitat segregation, we assessed the acute dose-mortality response to salinity of thirty-two larval populations from Central Africa. In agreement with its coastal predominance, Anopheles coluzzii was overall more tolerant than An. gambiae. Salinity tolerance of both species, however, converged in urban localities, presumably reflecting an adaptive response to osmotic stress from anthropogenic pollutants. When comparing degree of tolerance in conjunction with levels of syntopy, we found evidence of character displacement in this trait.Funding was provided by the Institut de Recherche pour le Dèveloppement, the National Institutes of Health (Projects R01 AI63508, and R01 AI76584 to NJB) and the Wellcome Trust (Intermediate Fellowship in Public Health and Tropical Medicine N° WT086423MA to CAN). PA was funded by the Spanish Ministerio de Economía y Competitividad (MINECO) and Universidad de Castilla-La Mancha (UCLM) through a ‘Ramón y Cajal’ contract(RYC-2012-11970). INAM was supported by a fellowship from the Universidad Nacional de Guinea Ecuatorial.Peer Reviewe

CRITICAL SPEED AND CRITICAL STROKE RATE COULD BE USEFUL PHYSIOLOGICAL AND TECHNICAL CRITERIA FOR COACHES TO MONITOR ENDURANCE PERFORMANCE IN COMPETITIVE SWIMMERS

The purposes of this study were to determine whether the concepts of critical swimming speed (CSS) and critical stroke rate (CSR) could be reliable and used by coaches in order to control and monitor endurance performance in competitive swimmers. The results of this study conducted with well-trained swimmers showed that CSS could be determined easily from two common distances and more accurately from 200- and 400-m tests after a correction of minus 1.4 %. Moreover, CSS was well correlated with swimming velocity corresponding to 4 mmol.l-1 of blood lactate concentration and could avoid using lactate testing. Furthermore, the concept of a critical stroke rate defined as ‘the stroke rate value, which can be theoretically maintained continuously indefinitely without exhaustion’ and expressed, as the slope of the regression line between the number of stroke cycles and time seemed to be reliable. Coaches, in order to set not only aerobic training loads but also to control swimming technique, could easily use CSS and CSR

Persistent BCG bacilli perpetuate CD4 T effector memory and optimal protection against tuberculosis

AbstractTuberculosis (TB) remains one of the most important infectious diseases of man and animals, and the only available vaccine (BCG) requires urgent replacement or improvement. To facilitate this, the protective mechanisms induced by BCG require further understanding. As a live attenuated vaccine, persistence of BCG bacilli in the host may be a crucial mechanism.We have investigated the long term persistence of BCG following vaccination and the influence on the induced immune response and protection, using an established murine model. We sought to establish whether previously identified BCG-specific CD4 TEM cells represent genuine long-lived memory cells of a relatively high frequency, or are a consequence of continual priming by chronically persistent BCG vaccine bacilli.By clearing persistent bacilli, we have compared immune responses (spleen and lung CD4: cytokine producing T effector/TEM; TCR-specific) and BCG-induced protection, in the presence and absence of these persisting vaccine bacilli. Viable BCG bacilli persisted for at least 16 months post-vaccination, associated with specific CD4 T effector/TEM and tetramer-specific responses. Clearing these bacilli abrogated all BCG-specific CD4 T cells whilst only reducing protection by 1log10.BCG may induce two additive mechanisms of immunity: (i) dependant on the presence of viable bacilli and TEM; and (ii) independent of these factors.These data have crucial implications on the rational generation of replacement TB vaccines, and the interpretation of BCG induced immunity in animal models