Plasma turbulence at ion scales: a comparison between PIC and Eulerian hybrid-kinetic approaches

Kinetic-range turbulence in magnetized plasmas and, in particular, in the context of solar-wind turbulence has been extensively investigated over the past decades via numerical simulations. Among others, one of the widely adopted reduced plasma model is the so-called hybrid-kinetic model, where the ions are fully kinetic and the electrons are treated as a neutralizing (inertial or massless) fluid. Within the same model, different numerical methods and/or approaches to turbulence development have been employed. In the present work, we present a comparison between two-dimensional hybrid-kinetic simulations of plasma turbulence obtained with two complementary approaches spanning about two decades in wavenumber - from MHD inertial range to scales well below the ion gyroradius - with a state-of-the-art accuracy. One approach employs hybrid particle-in-cell (HPIC) simulations of freely-decaying Alfv\'enic turbulence, whereas the other consists of Eulerian hybrid Vlasov-Maxwell (HVM) simulations of turbulence continuously driven with partially-compressible large-scale fluctuations. Despite the completely different initialization and injection/drive at large scales, the same properties of turbulent fluctuations at $k_\perp\rho_i\gtrsim1$ are observed. The system indeed self-consistently "reprocesses" the turbulent fluctuations while they are cascading towards smaller and smaller scales, in a way which actually depends on the plasma beta parameter. Small-scale turbulence has been found to be mainly populated by kinetic Alfv\'en wave (KAW) fluctuations for $\beta\geq1$, whereas KAW fluctuations are only sub-dominant for low-$\beta$.Comment: 18 pages, 4 figures, accepted for publication in J. Plasma Phys. (Collection: "The Vlasov equation: from space to laboratory plasma physics"

Collision-dependent power law scalings in 2D gyrokinetic turbulence

Nonlinear gyrokinetics provides a suitable framework to describe short-wavelength turbulence in magnetized laboratory and astrophysical plasmas. In the electrostatic limit, this system is known to exhibit a free energy cascade towards small scales in (perpendicular) real and/or velocity space. The dissipation of free energy is always due to collisions (no matter how weak the collisionality), but may be spread out across a wide range of scales. Here, we focus on freely-decaying 2D electrostatic turbulence on sub-ion-gyroradius scales. An existing scaling theory for the turbulent cascade in the weakly collisional limit is generalized to the moderately collisional regime. In this context, non-universal power law scalings due to multiscale dissipation are predicted, and this prediction is confirmed by means of direct numerical simulations.Comment: 7 pages, 5 figures, accepted for publication in Physics of Plasma

High accuracy transportable selectable-Value High Dc Voltage Standard

À l'Institut national de recherche metrologique (INRIM) il a été développé un étalon de haute tension continue avec des valeurs sélectionnables de 10 V à 100 V pour compenser le manque d'étalons de haut niveau de tension continue d'une valeur supérieure à 10 V pour les comparaisons interlaboratoires de haut niveau. Il a été utilisé une nouvelle technique électronique de terre mobile. L'étalon développé a un bruit inférieur et il a la stabilité égal à celle des calibrateurs de tension continue ou multifonction de haut niveau largement utilisé dans les laboratoires d'étalonnage électriques; il a aussi une meilleure attitude à être transporté pour les comparaisons interlaboratoires. Le projet est extensible jusqu'à 1000 V

The Amazon frontier of land-use change : croplands and consequences for greenhouse gas emissions

Author Posting. © American Meteorological Society, 2010. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Earth Interactions 14 (2010): 1–24, doi:10.1175/2010EI327.1.The Brazilian Amazon is one of the most rapidly developing agricultural frontiers in the world. The authors assess changes in cropland area and the intensification of cropping in the Brazilian agricultural frontier state of Mato Grosso using remote sensing and develop a greenhouse gas emissions budget. The most common type of intensification in this region is a shift from single- to double-cropping patterns and associated changes in management, including increased fertilization. Using the enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, the authors created a green-leaf phenology for 2001–06 that was temporally smoothed with a wavelet filter. The wavelet-smoothed green-leaf phenology was analyzed to detect cropland areas and their cropping patterns. The authors document cropland extensification and double-cropping intensification validated with field data with 85% accuracy for detecting croplands and 64% and 89% accuracy for detecting single- and double-cropping patterns, respectively. The results show that croplands more than doubled from 2001 to 2006 to cover about 100 000 km2 and that new double-cropping intensification occurred on over 20% of croplands. Variations are seen in the annual rates of extensification and double-cropping intensification. Greenhouse gas emissions are estimated for the period 2001–06 due to conversion of natural vegetation and pastures to row-crop agriculture in Mato Grosso averaged 179 Tg CO2-e yr−1, over half the typical fossil fuel emissions for the country in recent years.This work was supported by the NASA Earth and Space Science Fellowship (G. L. Galford) and Large-Scale Biosphere Atmosphere Experiment in Amazonia (Grant NNG06GE20A) and the Environmental Change Initiative at Brown University

Prospects for land-use sustainability on the agricultural frontier of the Brazilian Amazon

The Brazilian Amazon frontier shows how remarkable leadership can work towards increased agricultural productivity and environmental sustainability without new greenhouse gas emissions. This is due to initiatives among various stakeholders, including national and state government and agents, farmers, consumers, funding agencies and non-governmental organizations. Change has come both from bottom-up and top-down actions of these stakeholders, providing leadership, financing and monitoring to foster environmental sustainability and agricultural growth. Goals to reduce greenhouse gas emissions from land-cover and land-use change in Brazil are being achieved through a multi-tiered approach that includes policies to reduce deforestation and initiatives for forest restoration, as well as increased and diversified agricultural production, intensified ranching and innovations in agricultural management. Here, we address opportunities for the Brazilian Amazon in working towards low-carbon rural development and environmentally sustainable landscapes

NF-kB overexpression and decreased immunoexpression of AR in the muscular layer is related to structural damages and apoptosis in cimetidine-treated rat vas deferens

Background: Cimetidine, histamine H-2 receptors antagonist, has caused adverse effects on the male hormones and reproductive tract due to its antiandrogenic effect. in the testes, peritubular myoid cells and muscle vascular cells death has been associated to seminiferous tubules and testicular microvascularization damages, respectively. Either androgen or histamine H-2 receptors have been detected in the mucosa and smooth muscular layer of vas deferens. Thus, the effect of cimetidine on this androgen and histamine-dependent muscular duct was morphologically evaluated.Methods: the animals from cimetidine group (CMTG; n=5) received intraperitoneal injections of 100 mg/kg b.w. of cimetidine for 50 days; the control group (CG) received saline solution. the distal portions of vas deferens were fixed in formaldehyde and embedded in paraffin. Masson's trichrome-stained sections were subjected to morphological and the following morphometrical analyzes: epithelial perimeter and area of the smooth muscular layer. TUNEL (Terminal deoxynucleotidyl-transferase mediated dUTP Nick End Labeling) method, NF-kB (nuclear factor kappa B) and AR (androgen receptors) immunohistochemical detection were also carried out. the birefringent collagen of the muscular layer was quantified in picrosirius red-stained sections under polarized light. the muscular layer was also evaluated under Transmission Electron Microscopy (TEM).Results: in CMTG, the mucosa of vas deferens was intensely folded; the epithelial cells showed numerous pyknotic nuclei and the epithelial perimeter and the area of the muscular layer decreased significantly. Numerous TUNEL-labeled nuclei were found either in the epithelial cells, mainly basal cells, or in the smooth muscle cells which also showed typical features of apoptosis under TEM. While an enhanced NF-kB immunoexpression was found in the cytoplasm of muscle cells, a weak AR immunolabeling was detected in these cells. in CMTG, no significant difference was observed in the birefringent collagen content of the muscular layer in comparison to CG.Conclusions: Cimetidine induces significant damages in the epithelium; a possible antiandrogenic effect on the basal cells turnover should be considered. the cimetidine-induced muscle cells apoptosis confirms the susceptibility of these cells to this drug. the parallelism between enhanced cytoplasmic NF-kB immunolabeling in the damaged muscular tissue and muscle cell apoptosis suggests that this drug may avoid the translocation of NF-kB to the nucleus and interfere in the control of NF-kB-mediated smooth muscle cell apoptosis. the decreased immunoexpression of ARs verified in the damaged muscular tissue reinforces this possibility.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNESP, Araraquara Dent Sch, Lab Histol & Embryol, Dept Morphol, Jaboticabal, Estadual Paulis, BrazilFed Univ São Paulo UNIFESP, Dept Morphol & Genet, São Paulo, BrazilFed Univ São Paulo UNIFESP, Dept Morphol & Genet, São Paulo, BrazilFAPESP: 06/54776-6FAPESP: 08/53288-3FAPESP: 09/17895-5FAPESP: 10/02409-5Web of Scienc

PIN15 CHRONIC HEPATITIS B (CHB) MANAGEMENT COSTS IN SWEDEN

L'edifici fou construït l'any 1860, aproximadament.Primer pla, contrapicat d'un edifici d'habitatges entre mitgeres, en cantonada. Consta de planta baixa, cinc plantes pis i terrat. La façana és uniforme, de marcat estil academicista, amb un pòrtic amb pilars i arcs de mig punt a la planta baixa