461 research outputs found

    Spatio-temporal landslide inventory and susceptibility assessment using Sentinel-2 in the Himalayan mountainous region of Pakistan

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    The 2005 Kashmir earthquake has triggered widespread landslides in the Himalayan mountains in northern Pakistan and surrounding areas, some of which are active and are still posing a significant risk. Landslides triggered by the 2005 Kashmir earthquake are extensively studied; nevertheless, spatio-temporal landslide susceptibility assessment is lacking. This can be partially attributed to the limited availability of high temporal resolution remote sensing data. We present a semi-automated technique to use the Sentinel-2 MSI data for co-seismic landslide detection, landslide activities monitoring, spatio-temporal change detection, and spatio-temporal susceptibility mapping. Time series Sentinel-2 MSI images for the period of 2016–2021 and ALOS PALSAR DEM are used for semi-automated landslide inventory map development and temporal change analysis. Spectral information combined with topographical, contextual, textural, and morphological characteristics of the landslide in Sentinel-2 images is applied for landslide detection. Subsequently, spatio-temporal landslide susceptibility maps are developed utilizing the weight of evidence statistical modeling with seven causative factors, i.e., elevation, slope, geology, aspect, distance to fault, distance to roads, and distance to streams. The results reveal that landslide occurrence increased from 2016 to 2021 and that the coverage of areas of relatively high susceptibility has increased in the study area

    Management of Wetlands

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    The Efficacy, Safety, and Side Effects of Intrapericardial Triamcinolone Treatment in Children with Post-surgical Pericardial Effusion: A Case Series

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    Intrapericardial triamcinolone can be used to treat chronic pericardial effusion (PE) in adults; however, pediatric data are lacking. In this case series we aim to evaluate the efficacy, safety, and side effects of intrapericardial triamcinolone in children with PE. The incidence and treatment of post-surgical PE from 2009 to 2019 were determined using the institutional surgical database and electronic patient records. Furthermore, a retrospective analysis of efficacy, safety, and side effects of intrapericardial triamcinolone treatment for chronic post-surgical PE was performed. The incidence of postoperative PE requiring treatment was highest after atrial septal defect (ASD) closure when compared to other types of cardiac surgery (9.7% vs 4.3%). Intrapericardial treatment with triamcinolone resolved pericardial effusion in 3 out of 4 patients. All patients developed significant systemic side effects. Surgical ASD closure is associated with an increased risk of development of PE requiring treatment. Intrapericardial triamcinolone is an effective treatment for chronic postoperative PE in children, but is always associated with significant systemic side effects. Close monitoring and treatment of adrenal insufficiency are mandatory in these cases

    Mapping of semi-arid iron bearing red sands on emerged areas around lake marshes (Tablas de Daimiel, Spain) using hyperspectral DAIS 7915 spectrometer data

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    Wetlands are particularly sensitive environments receiving attention from the natural sciences community due to their wealth of both flora and fauna, and often considered as natural parks. In the Tablas de Daimiel (La Mancha, Central Spain), Digital Airborne Imaging Spectrometer data (DAIS 7915) have been analyzed to map geological processes on areas around the receding wetland which have never been flooded by water in the past. Sediments permanently exposed to the atmosphere dehydrate and oxide, developing different mineralogical associations arranged on planation surfaces. Such planation surfaces are key in the geological knowledge of recent climate change and landscape evolution. Progressive iron oxide/hydroxide rate and decarbonation can be spectrally followed on the Holocene sands framing the current marshy area. Such mineralogical changes are geologically registered on flat surfaces at different heights over the receding shore of the paleolake. Interacting erosion and sedimentation processes are responsible for the development of the flat morphological surfaces with increasing dryness. Maps are built for four different morphological units consisting of planation surfaces following chronologically the receding marsh during the last 2000 years before the present. Interactive spectral responses of mineralogical associations are described on the imagery, field and laboratory spectra

    Sunda-Banda arc transition: incipient continent-island arc collision (Northwest Australia)

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    The eastern Sunda arc represents one of the few regions globally where the early stages of continent-arc collision can be studied. We studied along the western limit of the collision zone at the Sunda-Banda arc transition, where the Australian margin collides with the Banda island arc, causing widespread back arc thrusting. We present integrated results of a refraction/wide-angle reflection tomography, gravity modeling, and multichannel reflection seismic imaging using data acquired in 2006 southeast of Sumba Island. The composite structural model reveals the previously unresolved deep geometry of the collision zone. Changes in crustal structure encompass the 10 - 12 km thick Australian basement in the south and the 22 - 24 kmthick Sumba ridge in the north, where backthrusting of the 130 km wide accretionary prism is documented. The structural diversity along this transect could be characteristic of young collisional systems at the transition from oceanic subduction to continent-arc collision. Citation: Shulgin, A., H. Kopp, C. Mueller, E. Lueschen, L. Planert, M. Engels, E. R. Flueh, A. Krabbenhoeft, and Y. Djajadihardja (2009), Sunda-Banda arc transition: Incipient continent-island arc collision (northwest Australia), Geophys. Res. Lett., 36, L10304, doi: 10.1029/2009GL037533

    Randomized controlled trial on the effect of 1-hour infusion of vincristine versus push injection on neuropathy in children with cancer (final analysis)

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    Introduction: Vincristine is an integral component of treatment for children with cancer. Its main dose-limiting side effect is vincristine-induced peripheral neuropathy (VIPN). The VINCA trial was a randomized controlled trial that explored the effect of 1-hour infusion compared with push injection of vincristine on the development of VIPN in children with cancer. The short-term outcomes (median follow-up 9 months) showed that there was no difference in VIPN between the randomization groups. However, 1-hour infusion was less toxic in children who also received azoles. We now report the results of the final analyses (median follow-up 20 months), which includes treatment outcome as a secondary objective (follow-up 3 years). Methods: VIPN was measured 1–7 times per participant using the Common Terminology Criteria for Adverse Events (CTCAE) and the pediatric-modified total neuropathy score. Poisson mixed model and logistic generalized estimating equation analysis for repeated measures were performed.Results: Forty-five participants per randomization group were included. There was no significant effect of 1-hour infusion compared with push injection on VIPN. In participants receiving concurrent azoles, the total CTCAE score was significantly lower in the one-hour group (rate ratio 0.52, 95% confidence interval 0.33–0.80, p = 0.003). Four patients in the one-hour group and one patient in the push group relapsed. Two patients in the one-hour group died. Conclusion:1-hour infusion of vincristine is not protective against VIPN. However, in patients receiving concurrent azoles, 1-hour infusion may be less toxic. The difference in treatment outcome is most likely the result of differences in risk profile.</p

    Thixotropy in macroscopic suspensions of spheres

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    An experimental study of the viscosity of a macroscopic suspension, i.e. a suspension for which Brownian motion can be neglected, under steady shear is presented. The suspension is prepared with a high packing fraction and is density-matched in a Newtonian carrier fluid. The viscosity of the suspension depends on the shear rate and the time of shearing. It is shown for the first time that a macroscopic suspension shows thixotropic viscosity, i.e. shear-thinning with a long relaxation time as a unique function of shear. The relaxation times show a systematic decrease with increasing shear rate. These relaxation times are larger when decreasing the shear rates, compared to those observed after increasing the shear. The time scales involved are about 10000 times larger than the viscous time scale and about 1000 times smaller than the thermodynamic time scale. The structure of the suspension at the outer cylinder of a viscometer is monitored with a camera, showing the formation of a hexagonal structure. The temporal decrease of the viscosity under shear coincides with the formation of this hexagonal pattern

    Square root singularity in the viscosity of neutral colloidal suspensions at large frequencies

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    The asymptotic frequency ω\omega, dependence of the dynamic viscosity of neutral hard sphere colloidal suspensions is shown to be of the form η0A(ϕ)(ωτP)−1/2\eta_0 A(\phi) (\omega \tau_P)^{-1/2}, where A(ϕ)A(\phi) has been determined as a function of the volume fraction ϕ\phi, for all concentrations in the fluid range, η0\eta_0 is the solvent viscosity and τP\tau_P the P\'{e}clet time. For a soft potential it is shown that, to leading order steepness, the asymptotic behavior is the same as that for the hard sphere potential and a condition for the cross-over behavior to 1/ωτP1/\omega \tau_P is given. Our result for the hard sphere potential generalizes a result of Cichocki and Felderhof obtained at low concentrations and agrees well with the experiments of van der Werff et al, if the usual Stokes-Einstein diffusion coefficient D0D_0 in the Smoluchowski operator is consistently replaced by the short-time self diffusion coefficient Ds(ϕ)D_s(\phi) for non-dilute colloidal suspensions.Comment: 18 pages LaTeX, 1 postscript figur
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