308 research outputs found
Integration of electrostatic and fluid dynamics within a dust devil
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94610/1/jgre2050.pd
Congenital coronary artery anomalies in adult population detected using dual source ECG-gated CTA in a single institution
Background: Congenital anomalies of the coronary arteries (CAs) are rare and are often diagnosed incidentally during a conventional coronary angiography. Recently, the incidence of these congenital defects is on the rise particularly after the introduction of the electrocardiography (ECG) gated coronary computed tomographic angiography (CCTA). This innovative radiological screening modality has led to the most precise mapping of the course of the CAs on computed tomographic scan. The aim of the study is to determine the prevalence and describe the CAs congenital anomalies and their variations in Kuwaiti population at a single institution experience.
Materials and methods: We analysed the CCTA data obtained consecutively from 842 patients (2013–2014), retrospectively. The inclusion criteria for patients’ selection were: atypical chest pain, equivocal ECG, assessment of patency of coronary stents or grafts and pre-operative screening. Information was acquiesced using a dual-source CT scanner with ECG gating.
Results: Data analysis revealed that 22 (2.61%) patients were found to have CA anomalies out of the 842 patients who underwent CCTA. Out of these CA anomalies, 13 cases showed more than two ostia, 7 cases showed the ectopic origin of a CA from opposite sinus or non-aortic sinus, 2 cases showed single coronary ostium and 1 case showed coronary artery with pulmonary fistula. Also, myocardial bridging was identified in 78 (9.26%) patients whereas ramus intermedius branch was identified in 160 (19%) patients.
Conclusions: The prevalence of CA anomalies in Kuwait was 2.6%, which is relatively higher than previously reported studies from different countries
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The ISSI international study team on the martian PBL – status report and plan
Dynamical processes in the Martian boundary layer provide the means of communication between surface ice deposits and the free atmosphere, and the means of lifting dust from the surface. The boundary layer is therefore one of the most important components of the Martian climate system. The Martian boundary layer differs from that of the Earth in that it is more strongly forced, it is deeper, and the relative importance of radiative and convective heat fluxes in the lower boundary layer can be quite different. In order to understand the Martian boundary layer, a combination of theoretical, modeling and observational studies are necessary. Interactions between theorists, modelers, and observational scientists are needed to make progress and to provide a basis for analysis of data expected from Phoenix, Mars Science Laboratory, ExoMars and other future landed missions (such as a surface network mission), or missions such as balloons or other aircraft operating in the neutral atmosphere. The prime goal of this project under the auspices of the International Space Science Institute (ISSI) is to review and assess the current knowledge and understanding of Martian planetary boundary layer and its interactions with the surface and free atmosphere. We aim to promote international communication and collaboration to enhance the rate of acquisition of knowledge and understanding. This will be achieved through an International Study Team and publication of overview papers and individual reports on recent advances in this area
A miniature sensor for electrical field measurements in dusty planetary atmospheres
"Dusty phenomena such as regular wind-blown dust, dust storms, and dust devils are the most important, currently active, geological processes on Mars. Electric fields larger than 100 kV/m have been measured in terrestrial dusty phenomena. Theoretical calculations predict that, close to the surface, the bulk electric fields in martian dusty phenomena reach the breakdown value of the isolating properties of thin martian air of about a few 10 kV/m. The fact that martian dusty phenomena are electrically active has important implications for dust lifting and atmospheric chemistry. Electric field sensors are usually grounded and distort the electric fields in their vicinity. Grounded sensors also produce large errors when subject to ion currents or impacts from clouds of charged particles. Moreover, they are incapable of providing information about the direction of the electric field, an important quantity. Finally, typical sensors with more than 10 cm of diameter are not capable of measuring electric fields at distances as small as a few cm from the surface. Measurements this close to the surface are necessary for studies of the effects of electric fields on dust lifting. To overcome these shortcomings, we developed the miniature electric-field sensor described in this article."http://deepblue.lib.umich.edu/bitstream/2027.42/64202/1/jpconf8_142_012075.pd
Determination of dust aerosol particle size at Gale Crater using REMS UVS and Mastcam measurements
We calculate the seasonal and interannual variation in dust aerosol particle size above Gale Crater during the first 1413 Martian solar days (sols = 24.6 h) of the Mars Science Laboratory mission. Measurements of UV radiation made by the Rover Environmental Monitoring Station in combination with atmospheric opacities retrieved from the Mastcam instrument are used for the calculations. Our results indicate that the dust effective radius varies significantly with season, ranging from ~0.6 μm during the low opacity season (Ls = 60°â 140°) to ~2 μm during the high opacity season (Ls = 180°â 360°). Our results suggest that Gale Crater is affected by dust events of high aerosol content originated at various distances from it. Our results improve the accuracy of estimations of ultraviolet radiation fluxes at the Martian surface. Moreover, our results have important implications because the lifetime of suspended dust and its ability to nucleate clouds are affected by particle size.Plain Language SummaryThe Martian atmosphere transports large amounts of dust, which interacts strongly with solar and infrared radiation. The large spatial and temporal variability in atmospheric dust load creates complex feedbacks connecting dust lifting with the evolving atmospheric circulations. The size of suspended aerosols affects the surface and atmospheric heating rates, influencing the Martian climate. In this work, we have calculated the dust aerosol particle size above Gale Crater during the first 1413 sols of the Mars Science Laboratory (MSL) mission using measurements of UV radiation made for the first time from the surface of Mars. Our results indicate that the dust effective radius varies significantly with season, ranging from ~0.6 μm during the clear season to ~2 μm during the dusty season. Our results suggest that Gale Crater is affected by dust events of high aerosol content originated at various distances from it. Our results are important because the lifetime of suspended dust and its ability to nucleate clouds are affected by the particle size.Key PointsWe have developed a novel methodology to retrieve dust aerosol particle size at Gale Crater using Mars Science Laboratory dataThe retrieved dust effective radii range from 0.6 μm during the clear aphelion season to 2 μm during the dusty perihelion seasonOur results improve the estimation of ultraviolet radiation fluxes at the Martian surfacePeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137189/1/grl55782-sup-0001-2017GL072589-SI.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137189/2/grl55782_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137189/3/grl55782.pd
TLR3 MATURATION, LOCALISATION AND APOPTOTIC ROLE IN CANCER
Oral Communication presented at the ";Forum des Jeunes Chercheurs";, Brest (France) 2011
Evaluation of the chromium-EDTA complex and creatinine as markers for urinary volume in cattle
Creatinine and intravenously infused Cr-EDTA complex were compared as markers for urinary volume estimation in cattle fed diets containing different concentrate levels. Ten Nellore heifers were used in a two-period crossover design and fed with two diets of divergent maize silage to concentrate ratios (90:10 and 50:50). The urinary marker concentrations were strongly and positively associated with each other, and both correlated strongly and negatively with total urine volume. Creatinine excretion and chromium recovery did not vary according to diets, but chromium recovery exhibited a lower variance among animals. The evaluation of urine spot samples showed that sampling time affects both markers, with the lowest urinary concentrations obtained when samples were taken early in the morning. Both creatinine and the Cr-EDTA complex produce similar estimates of urine volume. However, despite the greater precision of the estimates obtained with chromium, the values obtained with creatinine exhibited less bias and are, therefore, more accurate
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