149 research outputs found

    Modeling the Subsurface Structure of Sunspots

    Get PDF
    While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by \citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic

    Geokinematics of Central Europe: New insights from the CERGOP-2/Environment Project

    Get PDF
    The Central European Geodynamics Project CERGOP/2, funded by the European Union from 2003to 2006 under the 5th Framework Programme, benefited from repeated measurements of thecoordinates of epoch and permanent GPS stations of the Central European GPS Reference Network(CEGRN), starting in 1994. Here we report on the results of the systematic processing of availabledata up to 2005. The analysis has yielded velocities for some 60 sites, covering a variety of CentralEuropean tectonic provinces, from the Adria indenter to the Tauern window, the Dinarides, thePannonian Basin, the Vrancea seismic zone and the Carpathian Mountains. The estimated velocitiesdefine kinematical patterns which outline, with varying spatial resolution depending on the stationdensity and history, the present day surface kinematics in Central Europe. Horizontal velocities areanalyzed after removal from the ITRF2000 estimated velocities of a rigid rotation accounting forthe mean motion of Europe: a ~2.3 mm/yr north-south oriented convergence rate between Adria andthe Southern Alps that can be considered to be the present day velocity of the Adria indenterrelative to the European foreland. An eastward extrusion zone initiates at the Tauern Window. Thelateral eastward flow towards the Pannonian Basin exhibits a gentle gradient from 1-1.5 mm/yrimmediately east of the Tauern Window to zero in the Pannonian Basin. This kinematic continuityimplies that the Pannonian plate fragment recently suggested by seismic data does not require aspecific Eulerian pole. On the southeastern boundary of the Adria microplate, we report a velocitydrop from 4-4.5 mm/yr motion near Matera to ~1 mm/yr north of the Dinarides, in the southwesternpart of the Pannonian Basin. A positive velocity gradient as one moves south from West Ukraineacross Rumania and Bulgaria is estimated to be 2 mm/yr on a scale of 600-800 km, as if the crustwere dragged by the counterclockwise rotation along the North Anatolian Fault Zone. This regimeapparently does not interfere with the Vrancea seismic zone: earthquakes there are sufficiently deep(> 100 km) that the brittle deformation at depth can be considered as decoupled from the creep atthe surface. We conclude that models of the Quaternary tectonics of Central and Eastern Europeshould not neglect the long wavelength, nearly aseismic deformation affecting the upper crust in theRomanian and Bulgarian regions

    A Novel High-Content Flow Cytometric Method for Assessing the Viability and Damage of Rat Retinal Ganglion Cells

    Get PDF
    PURPOSE: The aim of the study was to develop a high-content flow cytometric method for assessing the viability and damage of small, medium, and large retinal ganglion cells (RGCs) in N-methyl-D-aspartic acid (NMDA)-injury model. METHODS/RESULTS: Retinal toxicity was induced in rats by intravitreal injection of NMDA and RGCs were retrogradely labeled with Fluoro-Gold (FG). Seven days post-NMDA injection, flatmount and flow cytometric methods were used to evaluate RGCs. In addition, the RGC area diameter (D((a))) obtained from retinal flatmount imaging were plotted versus apparent volume diameter (D((v))) obtained from flow cytometry for the same cumulative cell number (sequentially from small to large RGCs) percentile (Q) to establish their relationship for accurately determining RGC sizes. Good correlation (r = 0.9718) was found between D((a)) and apparent D((v)). Both flatmount and flow cytometric analyses of RGCs showed that 40 mM NMDA significantly reduced the numbers of small and medium RGCs but not large RGCs. Additionally, flow cytometry showed that the geometric means of FG and thy-1 intensities in three types of RGCs decreased to 90.96±2.24% (P<0.05) and 91.78±1.89% (P>0.05) for small, 69.62±2.11% (P<0.01) and 69.07±2.98% (P<0.01) for medium, and 69.68±6.48% (P<0.05) and 69.91±6.23% (P<0.05) for large as compared with the normal RGCs. CONCLUSION: The established flow cytometric method provides high-content analysis for differential evaluation of RGC number and status and should be useful for the evaluation of various models of optic nerve injury and the effects of potential neuroprotective agents

    A multidisciplinary consensus on the morphological and functional responses to immunotherapy treatment

    Get PDF
    The implementation of immunotherapy has radically changed the treatment of oncological patients. Currently, immunotherapy is indicated in the treatment of patients with head and neck tumors, melanoma, lung cancer, bladder tumors, colon cancer, cervical cancer, breast cancer, Merkel cell carcinoma, liver cancer, leukemia and lymphomas. However, its efficacy is restricted to a limited number of cases. The challenge is, therefore, to identify which subset of patients would benefit from immunotherapy. To this end, the establishment of immunotherapy response criteria and predictive and prognostic biomarkers is of paramount interest. In this report, a group of experts of the Spanish Society of Medical Oncology (SEOM), the Spanish Society of Medical Radiology (SERAM), and Spanish Society of Nuclear Medicine and Molecular Imaging (SEMNIM) provide an up-to-date review and a consensus guide on these issues

    Analysis of shared common genetic risk between amyotrophic lateral sclerosis and epilepsy

    Get PDF
    Because hyper-excitability has been shown to be a shared pathophysiological mechanism, we used the latest and largest genome-wide studies in amyotrophic lateral sclerosis (n = 36,052) and epilepsy (n = 38,349) to determine genetic overlap between these conditions. First, we showed no significant genetic correlation, also when binned on minor allele frequency. Second, we confirmed the absence of polygenic overlap using genomic risk score analysis. Finally, we did not identify pleiotropic variants in meta-analyses of the 2 diseases. Our findings indicate that amyotrophic lateral sclerosis and epilepsy do not share common genetic risk, showing that hyper-excitability in both disorders has distinct origins

    Pseudoprogression, radionecrosis, inflammation or true tumor progression? challenges associated with glioblastoma response assessment in an evolving therapeutic landscape

    Full text link
    The wide variety of treatment options that exist for glioblastoma, including surgery, ionizing radiation, anti-neoplastic chemotherapies, anti-angiogenic therapies, and active or passive immunotherapies, all may alter aspects of vascular permeability within the tumor and/or normal parenchyma. These alterations manifest as changes in the degree of contrast enhancement or T2-weighted signal hyperintensity on standard anatomic MRI scans, posing a potential challenge for accurate radiographic response assessment for identifying anti-tumor effects. The current review highlights the challenges that remain in differentiating true disease progression from changes due to radiation therapy, including pseudoprogression and radionecrosis, as well as immune or inflammatory changes that may occur as either an undesired result of cytotoxic therapy or as a desired consequence of immunotherapies
    • …
    corecore