1,959 research outputs found

    JVM-hosted languages: They talk the talk, but do they walk the walk?

    Get PDF
    The rapid adoption of non-Java JVM languages is impressive: major international corporations are staking critical parts of their software infrastructure on components built from languages such as Scala and Clojure. However with the possible exception of Scala, there has been little academic consideration and characterization of these languages to date. In this paper, we examine four nonJava JVM languages and use exploratory data analysis techniques to investigate differences in their dynamic behavior compared to Java. We analyse a variety of programs and levels of behavior to draw distinctions between the different programming languages. We briefly discuss the implications of our findings for improving the performance of JIT compilation and garbage collection on the JVM platform

    Screen-printed flexible MRI receive coils.

    Get PDF
    Magnetic resonance imaging is an inherently signal-to-noise-starved technique that limits the spatial resolution, diagnostic image quality and results in typically long acquisition times that are prone to motion artefacts. This limitation is exacerbated when receive coils have poor fit due to lack of flexibility or need for padding for patient comfort. Here, we report a new approach that uses printing for fabricating receive coils. Our approach enables highly flexible, extremely lightweight conforming devices. We show that these devices exhibit similar to higher signal-to-noise ratio than conventional ones, in clinical scenarios when coils could be displaced more than 18 mm away from the body. In addition, we provide detailed material properties and components performance analysis. Prototype arrays are incorporated within infant blankets for in vivo studies. This work presents the first fully functional, printed coils for 1.5- and 3-T clinical scanners

    On the application of dimensionality analysis to questions of interplanetary gas motion during solar flares

    Get PDF
    Dimensional analysis for interplanetary gas motion during solar flare

    Structural Analysis and Matrix Interpretive System /SAMIS/

    Get PDF
    SAMIS digital computer program simplifies automated structural analysis and eliminates reprogramming for problem changes. Program objectives are achieved by standardizing, by providing a modular program, and by programming for intermediate-size problems

    The STARTWAVE atmospheric water database

    Get PDF
    International audienceThe STARTWAVE (STudies in Atmospheric Radiative Transfer and Water Vapour Effects) project aims to investigate the role which water vapour plays in the climate system, and in particular its interaction with radiation. Within this framework, an ongoing water vapour database project was set up which comprises integrated water vapour (IWV) measurements made over the last ten years by ground-based microwave radiometers, Global Positioning System (GPS) receivers and sun photometers located throughout Switzerland at altitudes between 330 and 3584 m. At Bern (46.95° N, 7.44° E) tropospheric and stratospheric water vapour profiles are obtained on a regular basis and integrated liquid water, which is important for cloud characterisation, is also measured. Additional stratospheric water vapour profiles are obtained by an airborne microwave radiometer which observes large parts of the northern hemisphere during yearly flight campaigns. The database allows us to validate the various water vapour measurement techniques. Comparisons between IWV measured by the Payerne radiosonde with that measured at Bern by two microwave radiometers, GPS and sun photometer showed instrument biases within ±0.5 mm. The bias in GPS relative to sun photometer over the 2001 to 2004 period was ?0.8 mm at Payerne (46.81° N, 6.94° E, 490 m), which lies in the Swiss plains north of the Alps, and +0.6 mm at Davos (46.81° N, 9.84° E, 1598 m), which is located within the Alps in the eastern part of Switzerland. At Locarno (46.18° N, 8.78° E, 366 m), which is located on the south side of the Alps, the bias is +1.9 mm. The sun photometer at Locarno was found to have a bias of ?2.2 mm (13% of the mean annual IWV) relative to the data from the closest radiosonde station at Milano. This result led to a yearly rotation of the sun photometer instruments between low and high altitude stations to improve the calibrations. In order to demonstrate the capabilites of the database for studying water vapour variations, we investigated a front which crossed Switzerland between 18 November 2004 and 19 November 2004. During the frontal passage, the GPS and microwave radiometers at Bern and Payerne showed an increase in IWV of between 7 and 9 mm. The GPS IWV measurements were corrected to a standard height of 500 m, using an empirically derived exponential relationship between IWV and altitude. A qualitative comparison was made between plots of the IWV distribution measured by the GPS and the 6.2 µm water vapour channel on the Meteosat Second Generation (MSG) satellite. Both showed that the moist air moved in from a northerly direction, although the MSG showed an increase in water vapour several hours before increases in IWV were detected by GPS or microwave radiometer. This is probably due to the fact that the satellite instrument is sensitive to an atmospheric layer at around 320 hPa, which makes a contribution of one percent or less to the IWV

    Cryopreservation of Iberian red deer (Cervus elaphus hispanicus) spermatozoa obtained by electroejaculation

    Get PDF
    P. 628-638We tested extenders and freezing protocols for Iberian red deer semen. Samples were obtained by electroejaculation (10 stags), and analyzed for motility (CASA), viability (propidium ioide), acrosomal (PNA-FITC) and mitochondrial status (JC-1). Samples were diluted in extender, cooled and adjusted for glycerol (extender with higher glycerol concentration), brought to mL−1 and frozen. Four experiments were carried out, repeating sperm analysis after thawing to compare treatments. In a first experiment, seven samples were frozen using Triladyl® (20% egg yolk) and UL extender (Tes–Tris–fructose, 15% egg yolk, 4% glycerol). Triladyl® yielded higher motility after thawing. In a second trial, 17 samples were frozen using Triladyl®, Andromed®, Bioxcell®, and UL with 8% LDL (low-density lipoproteins). Triladyl® and Andromed® performed better than Bioxcell® on motility, and than UL-LDL on viability and acrosomal status. In a third experiment, the performance of freezing the sperm-rich ejaculate fraction versus the whole ejaculate was tested on nine samples. The sperm-rich ejaculate fraction not only rendered more motile and viable spermatozoa but also showed higher freezability (higher motile spermatozoa recovery). In a fourth experiment, we tried three modifications of the freezing protocol, for improving the freezability of low concentration samples: prior removal of seminal plasma; replacing extender (second fraction) for pure glycerol to reduce dilution; and performing only the dilution, not the second dilution. No differences were found, although only three samples could be used. Both Triladyl® and Andromed® were deemed appropriate for freezing Iberian red deer semen, and the rich fraction should be selected for freezing.S

    Overview of the 2007 and 2008 campaigns conducted as part of the Greenland Summit Halogen-HO\u3csub\u3ex\u3c/sub\u3e Experiment (GSHOX)

    Get PDF
    From 10 May through 17 June 2007 and 6 June through 9 July 2008 intensive sampling campaigns at Summit, Greenland confirmed that active bromine chemistry is occurring in and above the snow pack at the highest part of the Greenland ice sheet (72°36´ N, 38°25´ W and 3.2 km above sea level). Direct measurements found BrO and soluble gas phase Br− mixing ratios in the low pptv range on many days (maxima \u3c 10 pptv). Conversion of up to 200 pg m−3 of gaseous elemental mercury (GEM) to reactive gaseous mercury (RGM) and enhanced OH relative to HO2 plus RO2 confirm that active bromine chemistry is impacting chemical cycles even at such low abundances of reactive bromine species. However, it does not appear that Bry chemistry can fully account for observed perturbations to HOx partitioning, suggesting unknown additional chemical processes may be important in this unique environment, or that our understanding of coupled NOx-HOx-Brychemistry above sunlit polar snow is incomplete. Rapid transport from the north Atlantic marine boundary layer occasionally caused enhanced BrO at Summit (just two such events observed during the 12 weeks of sampling over the two seasons). In general observed reactive bromine was linked to activation of bromide (Br−) in, and release of reactive bromine from, the snowpack. A coupled snow-atmosphere model simulated observed NO and BrO at Summit during a three day interval when winds were weak. The source of Br− in surface and near surface snow at Summit is not entirely clear, but concentrations were observed to increase when stronger vertical mixing brought free tropospheric air to the surface. Reactive Bry mixing ratios above the snow often increased in the day or two following increases in snow concentration, but this response was not consistent. On seasonal time scales concentrations of Br− in snow and reactive bromine in the air were directly related

    Photonic crystal fibres: mapping Maxwell's equations onto a Schrodinger equation eigenvalue problem

    Get PDF
    We consider photonic crystal fibres (PCFs) made from arbitrary base materials and introduce a short-wavelength approximation which allows for a mapping of the Maxwell's equations onto a dimensionless eigenvalue equations which has the form of the Schrodinger equation in quantum mechanics. The mapping allows for an entire analytical solution of the dispersion problem which is in qualitative agreement with plane-wave simulations of the Maxwell's equations for large-mode area PCFs. We offer a new angle on the foundation of the endlessly single-mode property and show that PCFs are endlessly single mode for a normalized air-hole diameter smaller than ~0.42, independently of the base material. Finally, we show how the group-velocity dispersion relates simply to the geometry of the photonic crystal cladding.Comment: 16 pages including 6 figure

    Aerospace medicine and biology: A continuing bibliography with indexes, supplement 125

    Get PDF
    This special bibliography lists 323 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1974
    corecore