1,630 research outputs found
Long – Term Interest Rate and Fiscal Policy
The financial crisis of 2008, the subsequent fiscal stimulus, and damage to the fiscal
Tunable entanglement distillation of spatially correlated down-converted photons
We report on a new technique for entanglement distillation of the bipartite
continuous variable state of spatially correlated photons generated in the
spontaneous parametric down-conversion process (SPDC), where tunable
non-Gaussian operations are implemented and the post-processed entanglement is
certified in real-time using a single-photon sensitive electron multiplying CCD
(EMCCD) camera. The local operations are performed using non-Gaussian filters
modulated into a programmable spatial light modulator and, by using the EMCCD
camera for actively recording the probability distributions of the
twin-photons, one has fine control of the Schmidt number of the distilled
state. We show that even simple non-Gaussian filters can be finely tuned to a
~67% net gain of the initial entanglement generated in the SPDC process.Comment: 12 pages, 6 figure
Chemical Features in the Circumnuclear Disk of the Galactic Center
The circumnuclear disk (CND) of the Galactic Center is exposed to many
energetic phenomena coming from the supermassive black hole Sgr A* and stellar
activities. These energetic activities can affect the chemical composition in
the CND by the interaction with UV-photons, cosmic-rays, X-rays, and shock
waves. We aim to constrain the physical conditions present in the CND by
chemical modeling of observed molecular species detected towards it. We
analyzed a selected set of molecular line data taken toward a position in the
southwest lobe of the CND with the IRAM 30m and APEX 12-meter telescopes and
derived the column density of each molecule using a large velocity gradient
(LVG) analysis. The determined chemical composition is compared with a
time-dependent gas-grain chemical model based on the UCL\_CHEM code that
includes the effects of shock waves with varying physical parameters. Molecules
such as CO, HCN, HCO, HNC, CS, SO, SiO, NO, CN, HCO, HCN,
NH and HO are detected and their column densities are obtained.
Total hydrogen densities obtained from LVG analysis range between and cm and most species indicate values around
several cm, which are lower than values corresponding to
the Roche limit, which shows that the CND is tidally unstable. The chemical
models show good agreement with the observations in cases where the density is
cm, the cosmic-ray ionization rate is high, s, or shocks with velocities km s have occurred.
Comparison of models and observations favors a scenario where the cosmic-ray
ionization rate in the CND is high, but precise effects of other factors such
as shocks, density structures, UV-photons and X-rays from the Sgr A* must be
examined with higher spatial resolution data.Comment: 17 Pages, 13 figures, accepted for publication in A&
Abundant Z-cyanomethanimine in the interstellar medium: paving the way to the synthesis of adenine
We report the first detection in the interstellar medium of the Z-isomer of
cyanomethanimine (HNCHCN), an HCN dimer proposed as precursor of adenine. We
identified six transitions of Z-cyanomethanimine, along with five transitions
of E-cyanomethanimine, using IRAM 30m observations towards the Galactic Center
quiescent molecular cloud G+0.693. The Z-isomer has a column density of
(2.00.6)10 cm and an abundance of
1.510. The relative abundance ratio between the isomers is
[Z/E]6. This value cannot be explained by the two chemical formation
routes previously proposed (gas-phase and grain surface), which predicts
abundances ratios between 0.9 and 1.5. The observed [Z/E] ratio is in good
agreement with thermodynamic equilibrium at the gas kinetic temperature
(130210 K). Since isomerization is not possible in the ISM, the two species
may be formed at high temperature. New chemical models, including surface
chemistry on dust grains and gas-phase reactions, should be explored to explain
our findings. Whatever the formation mechanism, the high abundance of Z-HNCHCN
shows that precursors of adenine are efficiently formed in the ISM.Comment: Accepted in Monthly Notices of the Royal Astronomical Society Letter
Toward emotional interactive videogames for children with autism spectrum disorder
Technology and videogames have been proven as motivating tools for working attention and complex communication skills, especially in children with autism spectrum disorder (ASD). In this work, we present two experiences that used interactive games for promoting communication and attention. The first game considers emotions in order to measure children’s attention, concentration and satisfaction, while the second uses tangible tabletops for fostering cognitive planning. The analysis of the results obtained allows to propose a new study integrating both, in which the tangible interactive game is complemented with the emotional trainer in a way that allows identifying and classifying children’s emotion with ASD when they collaborate to solve cognitively significant and contextualized challenges. The first application proposed is an emotional trainer application in which the child can work out the seven basic emotions (happiness, sadness, fear, disgust, anger, surprise and neutral). Further, a serious videogame is proposed: a 3D maze where the emotions can be captured. The second case study was carried out in a Special Education Center, where a set of activities for working cognitive planning was proposed. In this case, a tangible interactive tabletop was used to analyze, in students with ASD, how the communication processes with these interfaces affect to the attention, memory, successive and simultaneous processing that compose cognitive planning from the PASS model. The results of the first study, suggest that the autistic children did not act with previous planning, but they used their perception to adjust their actions a posteriori (that explains the higher number of collisions). On the second case study, the successive processing was not explored. The inclusion of the mazes of case study 1 to a semantic rich scenario could allow us to measure the prior planning and the emotions involved in the maze game. The new physiological sensors will also help to validate the emotions felt by the children. The first study has as objective the capability to imitate emotions and resolve a maze without semantic context. The second study organized all the actions from a semantic context close to users. The attention results presented by the second study are coherent with the first study and complement it showing that attention can be receptive or selective. In the first study case, the receptive attention was the focus of analysis. In the second case, both contributed to explain and understand how it can be developed from a videogame
Complex organic molecules in the Galactic Centre: the N-bearing family
We present an unbiased spectral line survey toward the Galactic Centre (GC)
quiescent giant molecular cloud (QGMC), G+0.693 using the GBT and IRAM 30
telescopes. Our study highlights an extremely rich organic inventory of
abundant amounts of nitrogen (N)-bearing species in a source without signatures
of star formation. We report the detection of 17 N-bearing species in this
source, of which 8 are complex organic molecules (COMs). A comparison of the
derived abundances relative to H is made across various galactic and
extragalactic environments. We conclude that the unique chemistry in this
source is likely to be dominated by low-velocity shocks with X-rays/cosmic rays
also playing an important role in the chemistry. Like previous findings
obtained for O-bearing molecules, our results for N-bearing species suggest a
more efficient hydrogenation of these species on dust grains in G+0.693 than in
hot cores in the Galactic disk, as a consequence of the low dust temperatures
coupled with energetic processing by X-ray/cosmic ray radiation in the GC.Comment: 24 pages, 23 figures, 7 tables, accepted for publication in MNRA
Water Processable N-Type Organic Semiconductor
The present invention concerns a water-processable n-type semiconductor comprised of polyvinylpyrrolidone (PVP), carbon nanotubes (CNTs) and poly(ethyleneimine) (PEI). The semiconductors are prepared by providing PVP and CNTs in a hydrophilic slurry and dispersing therein small amounts of PEI
Discovering hierarchical decision rules with evolutive algorithms in supervised learning
This paper describes a new approach, HIDER (HIerarchical DEcision Rules), for learning
rules in continuous and discrete domains based on evolutive algorithms. The algorithm produces a
hierarchical set of rules, that is, the rules must be applied in a speciÞc order. With this policy, the
number of rules may be reduced because the rules could be one inside of another. The evolutive
algorithm uses both real and binary codiÞcation for the individuals of the population and introduces
several new genetic operators. In addition, this paper discusses the capability of learning systems
based on an evolutive algorithm to reduce both the number of rules and the number of attributes
involved in the rule set. We have tested our system on real data from the UCI repository. The results
of a 10-fold cross validation are compared to C4.5 s and they show an important improvement.Comisión Interministerial de Ciencia y Tecnología TIC99-035
- …