147 research outputs found

    Cirene : air-sea iInteractions in the Seychelles-Chagos thermocline ridge region

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    Author Posting. © American Meteorological Society, 2009. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 90 (2009): 1337-1350, doi:10.1175/2008BAMS2499.1.The Vasco—Cirene program ex-plores how strong air—sea inter-actions promoted by the shallow thermocline and high sea surface temperature in the Seychelles—Chagos thermocline ridge results in marked variability at synoptic, intraseasonal, and interannual time scales. The Cirene oceano-graphic cruise collected oceanic, atmospheric, and air—sea flux observations in this region in Jan-uary—February 2007. The contem-poraneous Vasco field experiment complemented these measure-ments with balloon deployments from the Seychelles. Cirene also contributed to the development of the Indian Ocean observing system via deployment of a moor-ing and 12 Argo profilers. Unusual conditions prevailed in the Indian Ocean during Janu-ary and February 2007, following the Indian Ocean dipole climate anomaly of late 2006. Cirene measurements show that the Seychelles—Chagos thermocline ridge had higher-than-usual heat content with subsurface anomalies up to 7°C. The ocean surface was warmer and fresher than average, and unusual eastward currents prevailed down to 800 m. These anomalous conditions had a major impact on tuna fishing in early 2007. Our dataset also sampled the genesis and maturation of Tropical Cyclone Dora, including high surface temperatures and a strong diurnal cycle before the cyclone, followed by a 1.5°C cool-ing over 10 days. Balloonborne instruments sampled the surface and boundary layer dynamics of Dora. We observed small-scale structures like dry-air layers in the atmosphere and diurnal warm layers in the near-surface ocean. The Cirene data will quantify the impact of these finescale features on the upper-ocean heat budget and atmospheric deep convection.CNES funded the Vasco part of the experiment; INSU funded the Cirene part. R/V Suroît is an Ifremer ship. The contributions from ODU, WHOI, and FOI (Sweden) are supported by the National Science Foundation under Grant Number 0525657. The participation of the University of Miami group was funded though NASA (NNG04HZ33C). PMEL participation was supported through NOAA’s Office of Climate Observation

    Continuous pulse advances in the negative ion source NIO1

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    Consorzio RFX and INFN-LNL have designed, built and operated the compact radiofrequency negative ion source NIO1 (Negative Ion Optimization phase 1) with the aim of studying the production and acceleration of H- ions. In particular, NIO1 was designed to keep plasma generation and beam extraction continuously active for several hours. Since 2020 the production of negative ions at the plasma grid (the first grid of the acceleration system) has been enhanced by a Cs layer, deposited though active Cs evaporation in the source volume. For the negative ion sources applied to fusion neutral beam injectors, it is essential to keep the beam current and the fraction of co-extracted electrons stable for at least 1 h, against the consequences of Cs sputtering and redistribution operated by the plasma. The paper presents the latest results of the NIO1 source, in terms of caesiation process and beam performances during continuous (6{\div}7 h) plasma pulses. Due to the small dimensions of the NIO1 source (20 x (diam.)10 cm), the Cs density in the volume is high (10^15 \div 10^16 m^-3) and dominated by plasma-wall interaction. The maximum beam current density and minimum fraction of co-extracted electrons were respectively about 30 A/m^2 and 2. Similarly to what done in other negative ion sources, the plasma grid temperature in NIO1 was raised for the first time, up to 80 {\deg}C, although this led to a minimal improvement of the beam current and to an increase of the co-extracted electron current.Comment: 11 pages, 7 figures. Contributed paper for the 8th International symposium on Negative Ions, Beams and Sources - NIBS'22. Revision 1 of the preprint under evaluation at Journal of Instrumentation (JINST

    Oral dosing of rodents using a palatable tablet

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    Rationale: Delivering orally bioavailable drugs to rodents is an important component to investigating that route of administration in novel treatments for humans. However, the traditional method of oral gavage requires training, is stressful, and can induce oesophageal damage in rodents. Objectives: To demonstrate a novel administrative technique – palatable gelatine tablets – as a stress-free route of oral delivery. Methods: 24 male Lister hooded rats were sacrificed for brain tissue analysis at varying time-points after jelly administration of 30 mg/kg of the wake-promoting drug modafinil. A second group of 22 female rats were tested on locomotor activity after 30 mg/kg modafinil, or after vehicle jellies, with the locomotor data compared to the brain tissue concentrations at the corresponding times. Results: Modafinil was present in the brain tissue at all time-points, reducing in concentration over time. The pattern of brain tissue modafinil concentration is comparable to previously reported results following oral gavage. Modafinil-treated rats were more active than control rats, with greater activity during the later time-periods – similar to that previously reported following intraperitoneal injection of 40 mg/kg modafinil. Conclusions: Palatable jelly tablets are an effective route of administration of thermally-stable orally-bioavailable compounds, eliminating the stress/discomfort and health risk of oral gavage and presenting as an alternative to previously reported palatable routes of administration where high protein and fat levels may adversely affect appetite for food reward, and uptake rate in the gastrointestinal tract.Publisher PDFPeer reviewe

    MRI of Arterial Flow Reserve in Patients with Intermittent Claudication: Feasibility and Initial Experience

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    Objectives: The aim of this work was to develop a MRI method to determine arterial flow reserve in patients with intermittent claudication and to investigate whether this method can discriminate between patients and healthy control subjects. Methods: Ten consecutive patients with intermittent claudication and 10 healthy control subjects were included. All subjects underwent vector cardiography triggered quantitative 2D cine MR phase-contrast imaging to obtain flow waveforms of the popliteal artery at rest and during reactive hyperemia. Resting flow, maximum hyperemic flow and absolute flow reserve were determined and compared between the two groups by two independent MRI readers. Also, interreader reproducibility of flow measures was reported. Results: Resting flow was lower in patients compared to controls (4.961.6 and 11.163.2 mL/s in patients and controls, respectively (p,0.01)). Maximum hyperemic flow was 7.362.9 and 16.463.2 mL/s (p,0.01) and the absolute flow reserve was 2.461.6 and 5.361.3 mL/s (p,0.01), respectively in patients and controls. The interreader coefficient of variation was below 10 % for all measures in both patients and controls. Conclusions: Quantitative 2D MR cine phase-contrast imaging is a promising method to determine flow reserve measures in patients with peripheral arterial disease and can be helpful to discriminate patients with intermittent claudication fro

    In Vivo Methods for the Assessment of Topical Drug Bioavailability

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    This paper reviews some current methods for the in vivo assessment of local cutaneous bioavailability in humans after topical drug application. After an introduction discussing the importance of local drug bioavailability assessment and the limitations of model-based predictions, the focus turns to the relevance of experimental studies. The available techniques are then reviewed in detail, with particular emphasis on the tape stripping and microdialysis methodologies. Other less developed techniques, including the skin biopsy, suction blister, follicle removal and confocal Raman spectroscopy techniques are also described

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