9,573 research outputs found
Surviving on Mars: test with LISA simulator
We present the biological results of some experiments performed in the Padua
simulators of planetary environments, named LISA, used to study the limit of
bacterial life on the planet Mars. The survival of Bacillus strains for some
hours in Martian environment is shortly discussed.Comment: To be published on Highlights of Astronomy, Volume 15 XXVIIth IAU
General Assembly, August 2009 Ian F Corbett, ed. 2 pages, 1 figur
LISA: Mars and the limits of life
We describe the results of the first tests made on LISA, a simulator of
planetary environments designed and built in Padua, dedicated to the study of
the limit of bacterial life on the planet Mars. Tests on the cryogenic circuit,
on the UV illumination and on bacterial coltures at room temperature that shall
be used as references are described.Comment: 4 pages, 3 figures. Mem. SAIt, in pres
Smooth optimal control with Floquet theory
This paper describes an approach to construct temporally shaped control
pulses that drive a quantum system towards desired properties. A
parametrization in terms of periodic functions with pre-defined frequencies
permits to realize a smooth, typically simple shape of the pulses; their
optimization can be performed based on a variational analysis with Floquet
theory. As we show with selected specific examples, this approach permits to
control the dynamics of interacting spins, such that gate operations and
entanglement dynamics can be implemented with very high accuracy
On the phase diagram of the Higgs SU(2) model
The Higgs SU(2) model with fixed Higgs length is usually believed to have two
different phases at high gauge coupling (\beta), separated by a line of first
order transitions but not distinuguished by any typical symmetry associated
with a local order parameter, as first proved by Fradkin and Shenker. We show
that in regions of the parameter space where it is usually supposed to be a
first order phase transition only a smooth crossover is in fact present.Comment: 6 pages, 6 figures. Talk presented at The XXVI International
Symposium on Lattice Field Theory, July 14 - 19, 2008 - Williamsburg,
Virginia, US
Urban MEMS based seismic network for post-earthquakes rapid disaster assessment
In this paper, we introduce a project for the realization
of the first European real-time urban seismic network
based on Micro Electro-Mechanical Systems (MEMS) technology.
MEMS accelerometers are a highly enabling technology,
and nowadays, the sensitivity and the dynamic range
of these sensors are such as to allow the recording of earthquakes
of moderate magnitude even at a distance of several
tens of kilometers. Moreover, thanks to their low cost and
smaller size, MEMS accelerometers can be easily installed in
urban areas in order to achieve an urban seismic network constituted
by high density of observation points. The network
is being implemented in the Acireale Municipality (Sicily,
Italy), an area among those with the highest hazard, vulnerability
and exposure to the earthquake of the Italian territory.
The main objective of the implemented urban network will
be to achieve an effective system for post-earthquake rapid
disaster assessment. The earthquake recorded, also that with
moderate magnitude will be used for the effective seismic
microzonation of the area covered by the network. The implemented
system will be also used to realize a site-specific
earthquakes early warning system
PIXE and ToF-SIMS analysis of streaker samplers filters
This paper presents methodological innovations introduced in the characterisation of urban aerosol collected in Italy in a recent campaign. Two complementary ion beam analysis (IBA) techniques were used to analyse Nuclepore filters used in continuous streaker samplers to collect airborne particles in four Italian towns. Na to Pb elemental concentrations were obtained by particle induced X-ray emission (PIXE), while time of flight secondary ion mass spectrometry (ToF-SIMS) produced, on the same samples, time trends for several elements and molecular fragments. In addition, light attenuation measurements were used as a tracer for black carbon. The data produced by these three techniques was merged into a unique data set to address the characterisation of particulate matter sources. Correlations between elemental concentration trends (PIXE) and relative trends for molecular fragments (ToF-SIMS) and black carbon (light attenuation) have been studied by cluster and principal component analysis
Degrees of controllability for quantum systems and applications to atomic systems
Precise definitions for different degrees of controllability for quantum
systems are given, and necessary and sufficient conditions are discussed. The
results are applied to determine the degree of controllability for various
atomic systems with degenerate energy levels and transition frequencies.Comment: 20 pages, IoP LaTeX, revised and expanded versio
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