The domain space of an analytic composition operator

In this paper we show that, for analytic composition operators between weighted Bergman spaces (including Hardy spaces) and as far as boundedness, compactness, order boundedness and certain summing properties of the adjoint are concerned, it is possible to modify domain spaces in a systematic fashion: there is a space of analytic functions which embeds continuously into each of the spaces under consideration and on which the above properties of the operator are decided. A remarkable consequence is that, in the setting of composition operators between weighted Bergman spaces, the properties in question can be identified as properties of the operator as a map between appropriately chosen Hilbert space

The domain space of an analytic composition operator

In this paper we show that, for analytic composition operators between weighted Bergman spaces (including Hardy spaces) and as far as boundedness, compactness, order boundedness and certain summing properties of the adjoint are concerned, it is possible to modify domain spaces in a systematic fashion: there is a space of analytic functions which embeds continuously into each of the spaces under consideration and on which the above properties of the operator are decided. A remarkable consequence is that, in the setting of composition operators between weighted Bergman spaces, the properties in question can be identified as properties of the operator as a map between appropriately chosen Hilbert space

Response of Ambulatory Human Subjects to Artificial Gravity (Short Radius Centrifugation)

Prolonged exposure to microgravity results in significant adaptive changes, including cardiovascular deconditioning, muscle atrophy, bone loss, and sensorimotor reorganization, that place individuals at risk for performing physical activities after return to a gravitational environment. Planned missions to Mars include unprecedented hypogravity exposures that would likely result in unacceptable risks to crews. Artificial gravity (AG) paradigms may offer multisystem protection from the untoward effects of adaptation to the microgravity of space or the hypogravity of planetary surfaces. While the most effective AG designs would employ a rotating spacecraft, perceived issues may preclude their use. The questions of whether and how intermittent AG produced by a short radius centrifuge (SRC) could be employed have therefore sprung to the forefront of operational research. In preparing for a series of intermittent AG trials in subjects deconditioned by bed rest, we have examined the responses of several healthy, ambulatory subjects to SRC exposures

Exploring the Notion of a National Data Infrastructure and the Governance Issues Surrounding It

A national data infrastructure (NDI) provides data, data-related services and guidelines for the re-use of data as an easily accessible service to citizens as well as public and private organizations. As such, it allows the efficient sharing of data between providers and consumers, supports new business models, and is thus a key enabler for the digital economy, societal collaboration and political processes. The paper relates to an ongoing project, discusses prevailing concepts on (data) infrastructure development and proposes a classification scheme for conceptualizing national data infrastructures in a given context. The discussion in particular focuses on governance issues related to establishing and maintaining a national data infrastructure that goes beyond the focus on open government data

First results on Martian carbon monoxide from Herschel/HIFI observations

We report on the initial analysis of Herschel/HIFI carbon monoxide (CO) observations of the Martian atmosphere performed between 11 and 16 April 2010. We selected the (7-6) rotational transitions of the isotopes ^{13}CO at 771 GHz and C^{18}O at 768 GHz in order to retrieve the mean vertical profile of temperature and the mean volume mixing ratio of carbon monoxide. The derived temperature profile agrees within less than 5 K with general circulation model (GCM) predictions up to an altitude of 45 km, however, show about 12-15 K lower values at 60 km. The CO mixing ratio was determined as 980 \pm 150 ppm, in agreement with the 900 ppm derived from Herschel/SPIRE observations in November 2009.Comment: Accepted for publication in Astronomy and Astrophysics (special issue on HIFI first results); minor changes to match published versio

Water production in comet 81P/Wild 2 as determined by Herschel/HIFI

The high spectral resolution and sensitivity of Herschel/HIFI allows for the detection of multiple rotational water lines and accurate determinations of water production rates in comets. In this Letter we present HIFI observations of the fundamental 1(10)-1(01) (557 GHz) ortho and 1(11)-0(00) (1113 GHz) para rotational transitions of water in comet 81P/Wild 2 acquired in February 2010. We mapped the extent of the water line emission with five point scans. Line profiles are computed using excitation models which include excitation by collisions with electrons and neutrals and solar infrared radiation. We derive a mean water production rate of 1.0 x 10(28) molecules s(-1) at a heliocentric distance of 1.61 AU about 20 days before perihelion, in agreement with production rates measured from the ground using observations of the 18-cm OH lines. Furthermore, we constrain the electron density profile and gas kinetic temperature, and estimate the coma expansion velocity by fitting the water line shapes.</p

ALMA spectral imaging of SL9 species in Jupiter’s stratosphere

In July 1994, the Shoemaker-Levy 9 comet (SL9) spectacularly impacted Jupiter near 44°S. On the long term, Jupiter was left with a variety of new species in its stratosphere, including CO, HCN, CS, H2O, and CO2. These species can be used as tracers for Jupiter’s stratospheric chemistry and dynamics. Their distributions have been monitored, although with strong limitations in terms of spatial resolution in most cases. We mapped the spectral emissions of CO and HCN (at 345 and 354 GHz, resp.) in Jupiter with ALMA in March 2017. We have successfully performed the first mosaic of Jupiter to cover the entire planet. We have recorded the data with a very high spectral resolution (up to 61 kHz) and at an unprecedented angular resolution of 1.1”, which translates into a meridional resolution of 3° at the equator and 7° at 70°S. The lines are detected at the planetary limb with a high signal-to-noise ratio. The emission distributions and line shapes at the limb indicate strong meridional variability for CO and HCN, quite different from one another. In this paper, we will present our observations and preliminary interpretation of the observed distributions