86,696 research outputs found
Geometry, stratigraphy and evidences for fluid expulsion within Crommelin crater deposits, Arabia Terra, Mars
No full textFluid expulsion processes are being recognized as a relevant process in the formation of deposits hosted in Arabia Terra impact craters. Objects of this study are the Equatorial Layered Deposits (ELDs) in the Crommelin crater area (equatorial Arabia Terra). Some of the depositional processes invoked
to explain their origin include spring deposition and mud volc
anism. In this work thickness and geometries of the crater filling
sediment packages were calculated. Stratigraphic contacts of
the Crommelin area were reported within a detailed geol
ogical map.
Potentially fluids related morphologies, such as furrows and mound clusters, were described in detail using HiRISE images, MOLA)based DEMs and high resolution HiRISE DEMs. The morphometric and morphological analyses revealed that mounds and other structures occur where the ELDs are thick
er and crudely layered. Orthorectfied imagery and high)res
olution topography seems to indicate the presence of conica
l mounds within the upper portion of ELDs near the craters r
ims. Those show apical holes and are linked to elongated struc
tures resembling veins and dikes. Inside Crommelin crater, within a
flat topography, elongated structures, formerly furrows, and
concentric strata pattern, that we refer to as ridge and through,
were described. MOLA based DEMs revealed that these morphologies are inconsistent with gravitative processes.
Mounds, furrows and related structures could be linked with deep fracture systems generated during the impact that trigger, at some – poorly constrained – point after the impact itself the potential upwelling of groundwater
Catheter inversion during cavotricuspid isthmus catheter ablation: the new shaft visualization catheter reduces fluoroscopy use
No full textAims: Catheter ablation (CA) is the choice therapy of cavotricuspid isthmus (CTI) atrial flutter. The aim of this study was to describe our approach to improve the CTI ablation using a zero-fluoroscopy (ZF). The procedural difficulties could be related to anatomical characteristics of the CTI. Methods: One hundred eighty-eight patients that performed CA of CTI were retrospectively and consecutively evaluated between 2017 and 2019. The studied population was divided into two groups. Eighty-eight patients who were undergone CA using ablation catheter without shaft visualization catheter (NSV) were Group 1. One hundred patients were undergone CA using ablation catheter with a shaft visualization (SV); they were Group 2. The catheter was looped at the Eustachian ridge after 200 seconds of radiofrequencies (RF) without elimination of local electrogram. Results: A conduction line block of CTI was obtained in all patients of Group 2 using a ZF approach. In 16 patients of Group 1, the catheter inversion was obtained using fluoroscopy to avoid damages during its loop. In Group 2, a complete CTI block was obtained with a catheter inversion approach in ten patients without fluoroscopy, visualizing the shaft and the tip of the ablation catheter on the electroanatomic (EAM) map. In the overall population studied the use of SV had a linear correlation with the ZF approach (r =.629; P <.001). The duration of RF was lower in Group 2 than in Group 1 (Group 1: 27.8 ± 6.3 vs Group 2: 15.6 ± 7.2 minutes; P <.01). The procedure time between two groups was lower in Group 2 than in Group 1 (Group 1: 58.4 ± 22.4 vs Group 2: 42.2 ± 15.7 minutes; P <.01). No differences between two groups were documented regarding success and complications. Conclusions: The visualization of the shaft's catheter on the EAM permitted the catheter inversion safely in order to overcome some complex CTI anatomy and obtain bidirectional block. The SV reduced procedure time, RF applications and fluoroscopy exposition during CTI ablation. © 2021 The Author
Fluid escape features in the Equatorial regions of Mars: landing site potential and constrains of early Mars hydrology.
No full textDepositional Controls of the Layered Deposits of Arabia Terra, Mars: Hints From Basin Geometries and Stratigraphic Trends
No full textAn extensive distribution of water-altered equatorial layered deposits (ELDs) characterizes the densely cratered terrain of Arabia Terra (AT), Mars. The majority of these deposits reside within craters and are easily identified by laterally continuous layering. The processes that led to their formation have been widely investigated, but remain unresolved. Furthermore, their precise spatial distribution as a whole, as well as their relationship to one another individually, has yet to be fully appreciated. This work examines 1,013 craters and emphasizes 45 that were observed to contain ELDs within the eastern half of AT. We present the statistical relationships between crater characteristics (e.g., location, diameter, depth), as well as evidence supporting a southeast-northwest facies change. The 30-2,000-m range of measured deposit thicknesses, accompanied with individual layer thicknesses, correlate with crater elevation either due to water level differences within craters, or a proximal-distal relationship to the source. Air fall or fluid expulsion appear to stand out among all the prevailing depositional hypotheses, however the volume required to fill these craters in an ash fall scenario is in opposition with the locations of known volcanic provinces and the volume of ash that volcanic eruptions produce. This new evidence of a regional facies change provides a unique opportunity to better understand past climate and sedimentary processes on Mars, as well as the putative groundwater level in ancient AT. Ultimately, our results do not agree well with a unified depositional method for these deposits and the possibility of mixed origins should be taken seriously
Long-wavelength groundwater discharge in Arabia Terra (Mars)
No full textPresence of past or present water on Mars is the strongest evidence of a living planet and an incentive for the astrobiological research looking for life signatures potentially preserved in the water-related rocks. New models of Mars hydrology localized groundwater upwelling sites in the equatorial lowlands where huge thickness of water-related sediments accompanied by peculiar morphologies have been deposited. Conical mounds and furrows are widely interpreted as the morphological evidences of fluids expulsion on the martian surface. In the Crommelin crater (equatorial Arabia Terra) furrows and conical mounds are exhumed within light-toned equatorial layered deposits (ELDs). Aim of this work is to describe these landforms assessing their potential relations with long wave-length groundwater upwelling in Crommelin area. Are the aqueous morphologies in the exact place where groundwater rises to the surface
Clinical characterization of non-ketotic hyperglycemia-related seizures: A systematic review and individual participant data meta-analysis
No full textNew-onset epileptic seizures and status epilepticus (SE) are the most frequent neurological manifestations of non-ketotic hyperglycemia (NKH), an acute complication of diabetes mellitus (DM). Treatment consists of the correction of the underlying metabolic disorder, whereas anti-seizure medications (ASMs) may even worsen seizures. Evidence on NKH-related seizures is currently restricted to case reports and small case-series. We conducted a systematic review of the PubMed, Embase, and Cochrane Library databases to provide a comprehensive description of NKH-related seizures. Statistical analyses were performed to explore possible associations of glycemic and osmolarity levels with clinical variables. We selected 130 publications and 332 patients (186 males, mean age: 61.1 years). DM was newly-diagnosed in 40%. Mean glycemia and osmolarity levels at presentation were 529.7 mg/dL and 309.6 mmol/mol, respectively; 22.6% showed other neurological symptoms besides seizures. Focal motor seizures were the prominent seizure type (49.4%); non-motor focal seizures (23.2%) most commonly manifested as visual symptoms. Reflex seizures occurred in 10.5%. Brain MRI in 48.7% of cases showed focal T2 subcortical hypodensity and/or overlying cortical T2 hyperintensity with DWI restriction. ASMs were administered in 54.2% of cases, achieving seizure control in just 18.3%. Higher osmolarity levels were associated with newly-diagnosed DM (p = 0.002) and other symptoms at presentation (p < 0.001). Glycemic values were higher in patients with focal aware seizures with motor onset compared to those with focal seizures without motor onset (p = 0.0046) or focal seizures with impaired awareness (p = 0.0306). Lower glycemic values were associated with reflex seizures (p = 0.036) and ASM administration (p < 0.001). NKH-related seizures should be suspected in adults with new-onset clustering focal seizures arising from the motor or posterior cortices, even in the absence of a history of DM. Typical focal changes on brain MRI, while not pathognomonic, can drive the clinical diagnosis. Statistical associations suggest a key role of hyperglycemia in the excitability of higher-energy-demanding cortical areas
Monitoraggio di aree ad elevata instabilità e di aree urbane con metodologie integrate di rilevamento
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