117 research outputs found

    GPS scintillations associated with cusp dynamics and polar cap patches

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    This paper investigates the relative scintillation level associated with cusp dynamics (including precipitation, flow shears, etc.) with and without the formation of polar cap patches around the cusp inflow region by the EISCAT Svalbard radar (ESR) and two GPS scintillation receivers. A series of polar cap patches were observed by the ESR between 8:40 and 10:20 UT on December 3, 2011. The polar cap patches combined with the auroral dynamics were associated with a significantly higher GPS phase scintillation level (up to 0.6 rad) than those observed for the other two alternatives, i.e., cusp dynamics without polar cap patches, and polar cap patches without cusp aurora. The cusp auroral dynamics without plasma patches were indeed related to GPS phase scintillations at a moderate level (up to 0.3 rad). The polar cap patches away from the active cusp were associated with sporadic and moderate GPS phase scintillations (up to 0.2 rad). The main conclusion is that the worst global navigation satellite system space weather events on the dayside occur when polar cap patches enter the polar cap and are subject to particle precipitation and flow shears, which is analogous to the nightside when polar cap patches exit the polar cap and enter the auroral oval

    Polar cap hot patches: enhanced density structures different from the classical patches in the ionosphere

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    Based on in situ and ground-based observations, a new type of “polar cap hot patch” has been identified that is different from the classical polar cap enhanced density structure (cold patches). Comparing with the classical polar cap patches, which are transported from the dayside sunlit region with dense and cold plasma, the polar cap hot patches are associated with particle precipitations (therefore field-aligned currents), ion upflows, and flow shears. The hot patches may have the same order of density enhancement as classical patches in the topside ionosphere, suggesting that the hot patches may be produced by transported photoionization plasma into flow channels. Within the flow channels, the hot patches have low-energy particle precipitation and/or ion upflows associated with field-aligned currents and flow shears. Corresponding Global Navigation Satellite System (GNSS) signal scintillation measurements indicate that hot patches may produce slightly stronger radio signal scintillation in the polar cap region than classical patches. A new type of polar cap patches, “polar cap hot patches,” is identified to differentiate enhanced density structures from classical patches. Hot patches are associated with particle precipitations, ion upflows, field-aligned currents, and shear flows in the polar cap. Hot patches may lead to slightly stronger ionospheric scintillations of GNSS signals in the polar cap region than classical patches

    Severe hypotension and water intoxication developed after an accidental oxytocin overdose in a morbidly obese patient undergoing cesarean section -A case report-

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    We present a 32-year-old, extremely obese, pregnant woman who developed severe hypotension and water intoxication after an accidental injection of large bolus of oxytocin during cesarean section under general anesthesia. The patient was initially thought to have an amniotic fluid embolism because of the abrupt hemodynamic changes developed immediately after fetal delivery and lack of recognition of medication error. It is highly recommended that careful attention should be paid not only to the possibility of hemodynamic deterioration and water intoxication if oxytocin is given rapidly in excessive doses, but to the confirmation of the proper use of the drug before it is injected

    Interferometric Study of Ionospheric Plasma Irregularities in Regions of Phase Scintillations and HF Backscatter

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    We investigate the nature of small-scale irregularities observed in the cusp by the Twin Rockets to Investigate Cusp Electrodynamics-2 (TRICE-2) in regions of enhanced phase scintillations and high-frequency coherent radar backscatter. We take advantage of the fact that the irregularities were detected by spatially separated probes, and present an interferometric analysis of both the observed electron density and electric field fluctuations. We provide evidence that fluctuations spanning a few decameters to about a meter have low phase velocity in the plasma reference frame and are nondispersive, confirming that decameter-scale irregularities follow the E × B velocity. Furthermore, we show that these “spatial” structures are intermittent and prominent outside of regions with strongest precipitation. The observations are then discussed in the context of possible mechanisms for irregularity creation.publishedVersio

    Perioperative management of massive hemoptysis during flexible bronchoscopy : Case report

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    La broncoscopia flexible es un procedimiento diagnóstico o terapéutico con baja incidencia de complicaciones (0,08-6,8%). El sangrado por biopsia transbronquial es una complicación rara (0-2,8% de los casos), suele ser leve y resuelve con medidas locales. No existe una definición clara de hemoptisis masiva y, por su baja incidencia, no hay guías de práctica clínica para el tratamiento de esta complicación, que puede ser catastrófica. Presentamos un caso de hemoptisis masiva durante la realización de una broncoscopia flexible más biopsia transbronquial y revisamos la literatura acerca del manejo intraoperatorio.Q3Reporte de caso256-261Flexible bronchoscopy is a diagnostic or therapeutic procedure with a low incidence of complications (0.08–6.8%). Bleeding after transbronchial biopsy is a rare complication (0-2.8% of the cases), usually resulting in minor bleeding that resolves with local measures. There is no clear definition of massive hemoptysis and due to the low incidence of this condition, there are no practical guidelines for the treatment of this complication that may be catastrophic. This case discusses the occurrence of massive hemoptysis during a transbronchial biopsy under flexible bronchoscopy, including a literature review on perioperative management

    Maternal and fetal genetic effects on birth weight and their relevance to cardio-metabolic risk factors.

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    Birth weight variation is influenced by fetal and maternal genetic and non-genetic factors, and has been reproducibly associated with future cardio-metabolic health outcomes. In expanded genome-wide association analyses of own birth weight (n = 321,223) and offspring birth weight (n = 230,069 mothers), we identified 190 independent association signals (129 of which are novel). We used structural equation modeling to decompose the contributions of direct fetal and indirect maternal genetic effects, then applied Mendelian randomization to illuminate causal pathways. For example, both indirect maternal and direct fetal genetic effects drive the observational relationship between lower birth weight and higher later blood pressure: maternal blood pressure-raising alleles reduce offspring birth weight, but only direct fetal effects of these alleles, once inherited, increase later offspring blood pressure. Using maternal birth weight-lowering genotypes to proxy for an adverse intrauterine environment provided no evidence that it causally raises offspring blood pressure, indicating that the inverse birth weight-blood pressure association is attributable to genetic effects, and not to intrauterine programming.The Fenland Study is funded by the Medical Research Council (MC_U106179471) and Wellcome Trust
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