1,136 research outputs found

    Steiner's formula in the Heisenberg group

    Get PDF
    Steiner's tube formula states that the volume of an ∈-neighborhood of a smooth regular domain in ℝn is a polynomial of degree n in the variable ∈ whose coefficients are curvature integrals (also called quermassintegrals). We prove a similar result in the sub-Riemannian setting of the first Heisenberg group. In contrast to the Euclidean setting, we find that the volume of an ∈-neighborhood with respect to the Heisenberg metric is an analytic function of ∈ that is generally not a polynomial. The coefficients of the series expansion can be explicitly written in terms of integrals of iteratively defined canonical polynomials of just five curvature terms

    Circulation and Stirring in the Southeast Pacific Ocean and the Scotia Sea Sectors of the Antarctic Circumpolar Current

    Get PDF
    The large-scale middepth circulation and eddy diffusivities in the southeast Pacific Ocean and Scotia Sea sectors between 110° and 45°W of the Antarctic Circumpolar Current (ACC) are described based on a subsurface quasi-isobaric RAFOS-float-based Lagrangian dataset. These RAFOS float data were collected during the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES). The mean flow, adjusted to a common 1400-m depth, shows the presence of jets in the time-averaged sense with speeds of 6 cm s⁻Âč in the southeast Pacific Ocean and upward of 13 cm s−Âč in the Scotia Sea. These jets appear to be locked to topography in the Scotia Sea but, aside from negotiating a seamount chain, are mostly free of local topographic constraints in the southeast Pacific Ocean. The eddy kinetic energy (EKE) is higher than the mean kinetic energy everywhere in the sampled domain by about 50%. The magnitude of the EKE increases drastically (by a factor of 2 or more) as the current crosses over the Hero and Shackleton fracture zones into the Scotia Sea. The meridional isopycnal stirring shows lateral and vertical variations with local eddy diffusivities as high as 2800 ± 600 m2 s⁻Âč at 700 m decreasing to 990 ± 200 mÂČ s⁻Âč at 1800 m in the southeast Pacific Ocean. However, the cross-ACC diffusivity in the southeast Pacific Ocean is significantly lower, with values of 690 ± 150 and 1000 ± 200 mÂČ s⁻Âč at shallow and deep levels, respectively, due to the action of jets. The cross-ACC diffusivity in the Scotia Sea is about 1200 ± 500 mÂČ s⁻Âč

    PolĂ­ticas sociales en Argentina: relaciones intergubernamentales, actores e implementaciĂłn en ciclos sociopolĂ­ticos

    Get PDF
    In recent decades in Argentina, social programs have been enacted in which various levels of government and non-state actors intervene. This process has been carried out since the beginning of this century, against the backdrop of neoliberalism, giving priority to three models that correspond to three sociopolitical cycles. In this framework, the general objective is to analyze which particularities intergovernmental relations (IRG) have materialized in social policy through different socio-historical cycles. Specifically, first of all, we propose to characterize the intergovernmental framework around social programs taking into account verticality and/or horizontality as well as formal and/or informal channels. Secondly, we address the implementation in the territory from material, functional and political dimensions. To do this, we combine a macro institutional and micro sociopolitical perspective. The theoretical - methodological strategy is qualitative supported by an interpretive paradigm that allows the research to be reorganized by articulating the theoretical framework with contributions of empirical support. The programs that we have selected are: Argentina Works converted into We Make the Future and then, in Empowering Work; the Young People with More and Better Work Program integrated with Promoting Employment; and the Territorial Roundtables Program.En las Ășltimas dĂ©cadas, se promulgaron programas sociales en Argentina en los cuales intervienen diversos niveles de gobierno y actores no estatales. Dicho proceso se realiza desde principios de este siglo, con el telĂłn de fondo del neoliberalismo, donde primaron tres modelos que corresponden a tres ciclos sociopolĂ­ticos. En este marco, el objetivo general es analizar las particularidades de las relaciones intergubernamentales (RIG) materializadas en la polĂ­tica social a travĂ©s de los diferentes ciclos sociohistĂłricos. EspecĂ­ficamente, en primer lugar, se caracteriza el entramado intergubernamental en torno a los programas sociales teniendo en cuenta la verticalidad y/u horizontalidad, y tambiĂ©n los canales formales y/o informales. En segundo lugar, se aborda la implementaciĂłn en el territorio desde dimensiones materiales, funcionales y polĂ­ticas

    Citizen Science as Democratic Innovation That Renews Environmental Monitoring and Assessment for the Sustainable Development Goals in Rural Areas

    Get PDF
    This commentary focuses on analyzing the potential of citizen science to address legitimacy issues in the knowledge base used to guide transformative governance in the context of the United Nation's Sustainable Development Goals (henceforth SDGs). The commentary develops two interrelated arguments for better understanding the limits of what we term "traditional" Environmental Monitoring and Assessment (EMA) as well as the potential of citizen science (CS) for strengthening the legitimacy of EMA in the local implementation of SDGs. We start by arguing that there is an urgent need for a profound renewal of traditional EMA to better implement the SDGs. Then, we present CS as a democratic innovation that provides a path to EMA renewal that incorporates, develops, and extends the role of CS in data production and use by EMA. The commentary substantiates such arguments based on current approaches to CS and traditional EMA. From this starting point, we theorize the potential of CS as a democratic innovation that can repurpose EMA as a tool for the implementation of the SDGs. With a focus on the implementation of SDG15 (Life on Land) in local contexts, the commentary presents CS as a democratic innovation for legitimate transformative governance that can affect socio-ecological transitions. We see this approach as especially appropriate to analyze the implementation of SDGs in rural settings where a specific resource nexus can create conflict-laden contexts with much potential for a renewed EMA to support transformative governance towards Agenda 2030

    Distinct serum and cerebrospinal fluid cytokine and chemokine profiles in autoantibody-associated demyelinating diseases

    Get PDF
    Background: Demyelinating diseases of the central nervous system associated with autoantibodies against aquaporin-4 and myelin-oligodendrocyte-glycoprotein are mediated by different immunopathological mechanisms compared to multiple sclerosis. Objective: The purpose of this study was to evaluate serum and cerebrospinal fluid cytokine/chemokine profiles in patients with autoantibodies against aquaporin-4 or autoantibodies against myelin-oligodendrocyte-glycoprotein-associated demyelination compared to multiple sclerosis and autoimmune encephalitis. Methods: Serum and cerebrospinal fluid cytokine/chemokine levels were analysed using Procartaplex Multiplex Immunoassays. First, we analysed a panel of 32 cytokines/chemokines in a discovery group (nine aquaporin-4-antibody seropositive, nine myelin oligodendrocyte glycoprotein-antibody seropositive, eight encephalitis, 10 multiple sclerosis). Significantly dysregulated cytokines/chemokines were validated in a second cohort (11 aquaporin-4-antibody seropositive, 18 myelin oligodendrocyte glycoprotein-antibody seropositive, 18 encephalitis, 33 multiple sclerosis). Results: We found 11 significantly altered cytokines/chemokines in cerebrospinal fluid and serum samples in the discovery group (a proliferation-inducing ligand, fractalkine=CX3CL1, growth-regulated oncogene-\u3b1, interleukin-1 receptor antagonist, interleukin-6, interleukin-8=CXCL8, interleukin-10, interleukin-21, interferon-&3-induced protein-10=CXCL10, monokine induced by interferon-&3=CXCL9, macrophage inflammatory protein-1 f=CCL4). Most of these cytokines/chemokines were up-regulated in autoantibodies against aquaporin-4 or autoantibodies against myelin-oligodendrocyte-glycoprotein positive patients compared to multiple sclerosis. We confirmed these results for cerebrospinal fluid interleukin-6 and serum interleukin-8, growth-regulated oncogene-\u3b1, a proliferation-inducing ligand and macrophage inflammatory protein-1\u3b2 in the validation set. Receiver-operating characteristic analysis revealed increased levels of cerebrospinal fluid interleukin-6, serum interleukin-8 and growth-regulated oncogene-\u3b1 in most patients with autoantibody-associated neurological diseases. Conclusion: This study suggests that distinctive cerebrospinal fluid and serum cytokine/chemokine profiles are associated with autoantibody-mediated demyelination, but not with multiple sclerosis

    Reliability and sensitivity to change of post-match physical performance measures in elite youth soccer players

    Get PDF
    IntroductionTo effectively monitor post-match changes in physical performance, valid, reliable and practical measures which are sensitive to change are required. This study aimed to quantify test-retest reliability and sensitivity to change of a range of physical performance measures recorded during an isometric posterior chain (IPC) lower-limb muscle test and a countermovement jump (CMJ) test.MethodsEighteen Italian Serie A academy soccer players performed three IPC repetitions per limb and five CMJ trials in 4 testing sessions. Test-retest reliability was evaluated between two testing sessions seven days apart using typical error of measurement, coefficient of variation and intraclass correlation coefficient. Sensitivity to change was assessed on two additional testing sessions performed before and immediately after a soccer match through Hedges' g effect size (g) and comparisons to typical error.ResultsAbsolute reliability (coefficient of variations) ranged from 1.5 to 8.8%. IPC and CMJ measures demonstrated moderate to excellent relative reliability (intraclass correlation coefficients ranged from 0.70 to 0.98). A wide range of physical performance measures showed significant alterations post-match (p < 0.05; g: small to moderate). IPC peak force and torque, CMJ reactive strength index modified, CMJ eccentric forces (mean breaking force, mean deceleration force, peak force, force at zero velocity) and CMJ mean power measures had post-match changes greater than their typical variation, demonstrating acceptable sensitivity in detecting performance changes at post-match.DiscussionIPC peak force and torque, CMJ reactive strength index modified, CMJ eccentric phase forces and CMJ mean power were found to be both reliable and sensitive to change, and thus may be appropriate for monitoring post-match neuromuscular performance in youth soccer population

    The Las Campanas/AAT Rich Cluster Survey III: Spectroscopic Studies of X-ray Bright Galaxy Clusters at z~0.1

    Full text link
    [abridged] We present the analysis of the spectroscopic and photometric catalogues of 11 X-ray luminous clusters at z=0.07-0.16 from the Las Campanas / Anglo-Australian Telescope Rich Cluster Survey. Our spectroscopic dataset consists of over 1600 galaxy cluster members, of which two thirds are outside r_200. We assign cluster membership using a detailed mass model and expand on our previous work on the cluster colour-magnitude relation where membership was inferred statistically. We confirm that the modal colours of galaxies on the colour magnitude relation become progressively bluer with increasing radius and decreasing local galaxy density. Interpreted as an age effect, we hypothesize that these trends in galaxy colour should be reflected in mean Hdelta equivalent width. We confirm that passive galaxies in the cluster increase in Hdelta line strength as dHdelta / d r_p = 0.35 +/- 0.06. A variation of star formation rate, as measured by [OII], with increasing local density of the environment is discernible and is shown to be in broad agreement with previous studies from 2dFGRS and SDSS. We find that clusters at z~0.1 are less active than their higher redshift analogues. We also investigate unusual populations of blue and very red nonstarforming galaxies and we suggest that the former are likely to be the progenitors of galaxies which will lie on the colour-magnitude relation, while the colours of the latter possibly reflect dust reddening. The cluster galaxies at large radii consist of both backsplash ones and those that are infalling to the cluster for the first time. We make a comparison to the field population at z~0.1 and examine broad differences between the two populations. Individually, the clusters show significant variation in their galaxy populations which reflects their recent infall histories.Comment: 25 pages, 16 figures. Accepted for publication in MNRA
    • 

    corecore