135 research outputs found
Electromagnetic Launch to Space
Many advances in electromagnetic (EM) propulsion technology have occurred in recent years. Linear motor technology for low-velocity and high-mass applications is being developed for naval catapults and missile launchers. Such technology could serve as the basis for the launch of a first-stage booster launch -for example, as suggested some years ago by the US National Aeronautics and Space Administration (NASA) in the Maglifter concept. For higher velocities, experimental laboratory railguns have demonstrated launch velocities of 2-3 km/s and muzzle energies greater than 10 MJ. The extension of this technology to the muzzle velocities (≥ 7500 m/s) and energies (hundreds of megajoules) needed for the direct launch of payloads into orbit is very challenging but may not be impossible. For launch to orbit, long launchers (> 1000 m) would need to operate at accelerations > 1000 G to reach the required velocities, so it would only be possible to launch rugged payloads, such as fuel, water, and material. This paper provides an overview of these concepts and includes a summary of the recent advances made in this area. PACS numbers: 96.12. Hg, 98.35.Eg, 94.30.Kq, 94.05.Rx, 94.20.Fg, 94.20.wc, 94.20.w
Hotel Intercontinental, en Ginebra (Suiza)
This is one of the largest hotels in Switzerland, having 400 bedrooms and a capacity for 800 guests, distributed in 15 storeys. There are also 3 restaurants, 3 bars, a dancing hall, a general hall, with installations for simultaneous translations, cinema shows, etc., with accommodation for 400 people, four lecture rooms, a number of luxurious shops, hairdressers and beauty salon, travelling agency, hot water pool, and other ameneties.
Its main merit is the right choice of materials, and the simple, elegant style of its outer shape and interior decoration.Este hotel, que es uno de los mayores construidos en Suiza, cuenta, entre sus dependencias, con 400 habitaciones que pueden acoger a 800 huéspedes y distribuidas en 15 plantas; tres restaurantes; tres bares; un salón de baile; un salón para múltiples usos, equipado con instalaciones de traducción simultánea, de proyección, etc., y en el cual pueden ser servidos banquetes de 400 cubiertos; cuatro salas de conferencias; una serie de lujosas tiendas; peluquería y salón de belleza; agencias de viajes; piscina con agua caliente; etc.
Su mayor atractivo reside en la acertada elección de los materiales empleados en su construcción, así como en la elegancia y sencillez de líneas exteriores y decoración interior
Shortened Tracer Uptake Time in GA-68-DOTATOC-PET of Meningiomas Does Not Impair Diagnostic Accuracy and PET Volume Definition
Ga-68-DOTATOC-PET/MRI can affect the planning target volume (PTV) definition of meningiomas before radiosurgery. A shorter tracer uptake time before image acquisition could allow the examination of more patients. The aim of this study was to investigate if shortening uptake time is possible without compromising diagnostic accuracy and PET volume. Fifteen patients (f = 12; mean age 52 years (34-80 years)) with meningiomas were prospectively examined with dynamic [68Ga]Ga-68-labeled [DOTA0-Phe1-Tyr3] octreotide (Ga-68-DOTATOC)-PET/MRI over 70 min before radiosurgery planning. Meningiomas were delineated manually in the PET dataset. PET volumes at each time point were compared to the reference standard 60 min post tracer injection (p.i.) using the Friedman test followed by a Wilcoxon signed-rank test and Bonferroni correction. In all patients, the earliest time point with 100% lesion detection compared to 60 min p.i. was identified. PET volumes did not change significantly from 15 min p.i. (p = 1.0) compared to 60 min p.i. The earliest time point with 100% lesion detection in all patients was 10 min p.i. In patients with meningiomas undergoing Ga-68-DOTATOC-PET, the tracer uptake time can safely be reduced to 15 min p.i. with comparable PET volume and 100% lesion detection compared to 60 min p.i
Effects of external nutrient sources and extreme weather events on the nutrient budget of a Southern European coastal lagoon
The seasonal and annual nitrogen (N), phosphorus (P), and carbon (C) budgets of the mesotidal Ria Formosa lagoon, southern Portugal, were estimated to reveal the main inputs and outputs, the seasonal patterns, and how they may influence the ecological functioning of the system. The effects of extreme weather events such as long-lasting strong winds causing upwelling and strong rainfall were assessed. External nutrient inputs were quantified; ocean exchange was assessed in 24-h sampling campaigns, and final calculations were made using a hydrodynamic model of the lagoon. Rain and stream inputs were the main freshwater sources to the lagoon. However, wastewater treatment plant and groundwater discharges dominated nutrient input, together accounting for 98, 96, and 88 % of total C, N, and P input, respectively. Organic matter and nutrients were continuously exported to the ocean. This pattern was reversed following extreme events, such as strong winds in early summer that caused upwelling and after a period of heavy rainfall in late autumn. A principal component analysis (PCA) revealed that ammonium and organic N and C exchange were positively associated with temperature as opposed to pH and nitrate. These variables reflected mostly the benthic lagoon metabolism, whereas particulate P exchange was correlated to Chl a, indicating that this was more related to phytoplankton dynamics. The increase of stochastic events, as expected in climate change scenarios, may have strong effects on the ecological functioning of coastal lagoons, altering the C and nutrient budgets.Portuguese Science and Technology Foundation (FCT) [POCI/MAR/58427/2004, PPCDT/MAR/58427/2004]; Portuguese Science and Technology Foundation (FCT
Effective detection of human adenovirus in hawaiian waters using enhanced pcr methods
<p>Abstract</p> <p>Background</p> <p>The current criteria for recreational water quality evaluation are primarily based on measurements of fecal indicator bacteria growth. However, these criteria often fail to predict the presence of waterborne human pathogenic viruses. To explore the possibility of direct use of human enteric viruses as improved human fecal contamination indicators, human adenovirus (HAdV) was tested as a model in this study.</p> <p>Findings</p> <p>In order to establish a highly sensitive protocol for effective detection of HAdV in aquatic environments, sixteen published PCR primer sets were re-optimized and comparatively evaluated. Primer sets nehex3deg/nehex4deg, ADV-F/ADV-R, and nested PCR primer sets hex1deg/hex2deg and nehex3deg/nehex4deg were identified to be the most sensitive ones, with up to 1,000 fold higher detection sensitivity compared to other published assays. These three PCR protocols were successfully employed to detect HAdV in both treated and untreated urban wastewaters, and also in 6 of 16 recreational water samples collected around the island of Oahu, Hawaii.</p> <p>Conclusions</p> <p>Findings from this study support the possible use of enteric viruses for aquatic environmental monitoring, specifically for the essential routine monitoring of Hawaiian beach waters using the optimized PCR protocol to detect HAdV at certain water sites to ensure a safe use of recreational waters.</p
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
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