12,596 research outputs found
The ESO Spectroscopic facility
We present the concept of a novel facility dedicated to massively-multiplexed
spectroscopy. The telescope has a very wide field Cassegrain focus optimised
for fibre feeding. With a Field of View (FoV) of 2.5 degrees diameter and a
11.4m pupil, it will be the largest etendue telescope. The large focal plane
can easily host up to 16.000 fibres. In addition, a gravity invariant focus for
the central 10 arc-minutes is available to host a giant integral field unit
(IFU). The 3 lenses corrector includes an ADC, and has good performance in the
360-1300 nm wavelength range. The top level science requirements were developed
by a dedicated ESO working group, and one of the primary cases is high
resolution spectroscopy of GAIA stars and, in general, how our Galaxy formed
and evolves. The facility will therefore be equipped with both, high and low
resolution spectrographs. We stress the importance of developing the telescope
and instrument designs simultaneously. The most relevant R\&D aspect is also
briefly discussed.Comment: 6 pages 4 figures , presented at IAU Symposium 334 "rediscovering our
galaxy
Fractional-Spin Integrals of Motion for the Boundary Sine-Gordon Model at the Free Fermion Point
We construct integrals of motion (IM) for the sine-Gordon model with boundary
at the free Fermion point which correctly determine the boundary S matrix. The
algebra of these IM (``boundary quantum group'' at q=1) is a one-parameter
family of infinite-dimensional subalgebras of twisted affine sl(2). We also
propose the structure of the fractional-spin IM away from the free Fermion
point.Comment: 19 pages, LaTeX, no figure
Using the UN Human Rights System to Advocate for Access to Palliative Care and Pain Relief
This toolkit is a resource for organizations that want to advocate for increased access to palliative care and pain relief as a human right within the United Nations human rights system. The toolkit introduces the UN human rights system and offers step-by-step advice and resources on how to navigate it, including various treaty bodies and the UN Human Rights Council. It also discusses how to advocate for palliative care and access to pain relief in regional human rights systems
A Few Considerations on Structural and Logical Composition in Specification Theories
Over the last 20 years a large number of automata-based specification
theories have been proposed for modeling of discrete,real-time and
probabilistic systems. We have observed a lot of shared algebraic structure
between these formalisms. In this short abstract, we collect results of our
work in progress on describing and systematizing the algebraic assumptions in
specification theories.Comment: In Proceedings FIT 2010, arXiv:1101.426
Atrioventricular canal defect and genetic syndromes: the unifying role of sonic hedgehog
The atrioventricular canal defect (AVCD) is a congenital heart defect (CHD) frequently associated with extracardiac anomalies (75%). Previous observations from a personal series of patients with AVCD and "polydactyly syndromes" showed that the distinct morphology and combination of AVCD features in some of these syndromes is reminiscent of the cardiac phenotype found in heterotaxy, a malformation complex previously associated with functional cilia abnormalities and aberrant Hedgehog (Hh) signaling. Hh signaling coordinates multiple aspects of left-right lateralization and cardiovascular growth. Being active at the venous pole the secondary heart field (SHF) is essential for normal development of dorsal mesenchymal protrusion and AVCD formation and septation. Experimental data show that perturbations of different components of the Hh pathway can lead to developmental errors presenting with partially overlapping manifestations and AVCD as a common denominator. We review the potential role of Hh signaling in the pathogenesis of AVCD in different genetic disorders. AVCD can be viewed as part of a "developmental field," according to the concept that malformations can be due to defects in signal transduction cascades or pathways, as morphogenetic units which may be altered by Mendelian mutations, aneuploidies, and environmental causes
Ballistic effectiveness of Zr-containing composite solid propellants as a function of binder nature and mass fraction
This paper considers the effects of binder mass fraction on the properties of energetic formulations based on zirconium and zirconium hydride. These ingredients, replacing aluminum in solid rocket motors with low vehicle performance coefficient, may increase the propellant ballistic effectiveness, thanks to the resulting higher density and notwithstanding their lower specific impulse. The propellant ballistic effectiveness is estimated via the vehicle velocity achieved using the propellant under analysis in a real vehicle. For each specific mission, the binder content can be varied to provide the optimal relationship between energetic and physical-mechanical properties, that is, one may sacrifice energy in favor of rheological and physicomechanical properties (increasing binder mass fraction), or vice versa
A space-time generator for rainfall nowcasting: the PRAISEST model
International audienceThe paper introduces a new stochastic technique for forecasting rainfall in space-time domain: the PRAISEST Model (Prediction of Rainfall Amount Inside Storm Events: Space and Time). The model is based on the assumption that the rainfall height H accumulated on an interval ?t between the instants i?t and (i+1)?t and on a spatial cell of size ?x?y is correlated either with a variable Z, representing antecedent precipitation at the same point, either with a variable W, representing simultaneous rainfall at neighbour cells. The mathematical background is given by a joined probability density fH,W,Z (h,w,z) in which the variables have a mixed nature, that is a finite probability for null value and infinitesimal probabilities for the positive values. As study area, the Calabria region, in Southern Italy, has been selected. The region has been discretised by 10 kmĂ—10 km cell grid, according to the raingauge network density in this area. Storm events belonging to 1990?2004 period were analyzed to test performances of the PRAISEST model
Rainfall nowcasting by at site stochastic model P.R.A.I.S.E.
The paper introduces a stochastic model to forecast rainfall heights at
site: the P.R.A.I.S.E. model (Prediction of Rainfall Amount Inside Storm
Events). PRAISE is based on the assumption that the rainfall height <I>H<sub>i</I>+1</sub>
accumulated on an interval Δ<I>t</I> between the instants <I>iΔt</I> and
<I>(i+1Δt</I> is correlated with a variable <I>Z<sub>i<sup>(ν)</sup></sub></I>,
representing antecedent precipitation. The mathematical
background is given by a joined probability density <I>f<sub>H<sub>i+1</sub></sub>, Z<sub>i</sub><sup>(ν)</sup>(h<sub>i+1</sub> ,z<sub>i</sub><sup>(ν)</sup></I>) in which
the variables have a mixed nature, that is a finite probability in
correspondence to the null value and infinitesimal probabilities in
correspondence to the positive values. As study area, the Calabria region,
in Southern Italy, was selected, to test performances of the PRAISE model
Occurrence analysis of daily rainfalls through non-homogeneous Poissonian processes
Abstract. A stochastic model based on a non-homogeneous Poisson process, characterised by a time-dependent intensity of rainfall occurrence, is employed to explain seasonal effects of daily rainfalls exceeding prefixed threshold values. The data modelling has been performed with a partition of observed daily rainfall data into a calibration period for parameter estimation and a validation period for checking on occurrence process changes. The model has been applied to a set of rain gauges located in different geographical areas of Southern Italy. The results show a good fit for time-varying intensity of rainfall occurrence process by 2-harmonic Fourier law and no statistically significant evidence of changes in the validation period for different threshold values
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