5,305 research outputs found
Innovation, R&D and Productivity in the Costa Rican ICT Sector: A Case Study
This paper addresses the relationships between innovation, research and development (R&D) and productivity in domestic ICT firms in Costa Rica. Factors considered were the types of innovation outputs produced by domestic ICT firms, the relative importance of innovation inputs, the impacts of innovation on firm productivity, the protection of innovations, and impediments to innovation. While most firms engaged in all types of output and input innovations, they appear to be driven by retaining or increasing market share rather than increasing productivity. Half of firms do not formally protect the intellectual property created by their innovations, are not familiar with methods for protecting innovation or the availability of government grants for such purposes, and face barriers associated with the Costa Rican Patent Office. Other impediments include lack of knowledge about financial resources available and scarcity of human resources. There is also evidence of knowledge spillovers through worker mobility from multinationals operating in Costa Rica to domestic ICT firms
Kinematics of the ionized-to-neutral interfaces in Monoceros R2
Context. Monoceros R2 (Mon R2), at a distance of 830 pc, is the only
ultra-compact H ii region (UC H ii) where its associated photon-dominated
region (PDR) can be resolved with the Herschel Space Observatory. Aims. Our aim
is to investigate observationally the kinematical patterns in the interface
regions (i.e., the transition from atomic to molecular gas) associated with Mon
R2. Methods. We used the HIFI instrument onboard Herschel to observe the line
profiles of the reactive ions CH+, OH+ and H2O+ toward different positions in
Mon R2. We derive the column density of these molecules and compare them with
gas-phase chemistry models. Results. The reactive ion CH+ is detected both in
emission (at central and red-shifted velocities) and in absorption (at
blue-shifted velocities). OH+ is detected in absorption at both blue- and
red-shifted velocities, with similar column densities. H2O+ is not detected at
any of the positions, down to a rms of 40 mK toward the molecular peak. At this
position, we find that the OH+ absorption originates in a mainly atomic medium,
and therefore is associated with the most exposed layers of the PDR. These
results are consistent with the predictions from photo-chemical models. The
line profiles are consistent with the atomic gas being entrained in the ionized
gas flow along the walls of the cavity of the H ii region. Based on this
evidence, we are able to propose a new geometrical model for this region.
Conclusions. The kinematical patterns of the OH+ and CH+ absorption indicate
the existence of a layer of mainly atomic gas for which we have derived, for
the first time, some physical parameters and its dynamics.Comment: 6 pages, 5 figures. Accepted for publication in A&
The first CO+ image: Probing the HI/H2 layer around the ultracompact HII region Mon R2
The CO+ reactive ion is thought to be a tracer of the boundary between a HII
region and the hot molecular gas. In this study, we present the spatial
distribution of the CO+ rotational emission toward the Mon R2 star-forming
region. The CO+ emission presents a clumpy ring-like morphology, arising from a
narrow dense layer around the HII region. We compare the CO+ distribution with
other species present in photon-dominated regions (PDR), such as [CII] 158 mm,
H2 S(3) rotational line at 9.3 mm, polycyclic aromatic hydrocarbons (PAHs) and
HCO+. We find that the CO+ emission is spatially coincident with the PAHs and
[CII] emission. This confirms that the CO+ emission arises from a narrow dense
layer of the HI/H2 interface. We have determined the CO+ fractional abundance,
relative to C+ toward three positions. The abundances range from 0.1 to
1.9x10^(-10) and are in good agreement with previous chemical model, which
predicts that the production of CO+ in PDRs only occurs in dense regions with
high UV fields. The CO+ linewidth is larger than those found in molecular gas
tracers, and their central velocity are blue-shifted with respect to the
molecular gas velocity. We interpret this as a hint that the CO+ is probing
photo-evaporating clump surfaces.Comment: The main text has 4 pages, 2 pages of Appendix, 4 figures, 1 table.
Accepted for publication in Astronomy and Astrophysics letter
Enantio- and Diastereoselective Nucleophilic Addition of N-tert-Butylhydrazones to Isoquinolinium Ions through Anion-Binding Catalysis
A highly enantio- and diastereoselective thiourea-catalyzed dearomatization of isoquinolines employing N-tert-butylhydrazones as neutral alpha-azo carbanions and masked acyl anion equivalents has been developed. Experimental and computational data supports the generation of highly ordered complexes wherein the chloride behaves as a template for the catalyst, the hydrazone reagent, and the isoquinolinium cation, providing excellent stereocontrol in the formation of two contiguous stereogenic centers. The ensuing selective and high-yielding transformations provide appealing dihydroisoquinoline derivatives
The NH2D/NH3 ratio toward pre-protostellar cores around the UCHII region in IRAS 20293+3952
The deuterium fractionation, Dfrac, has been proposed as an evolutionary
indicator in pre-protostellar and protostellar cores of low-mass star-forming
regions. We investigate Dfrac, with high angular resolution, in the cluster
environment surrounding the UCHII region IRAS 20293+3952. We performed high
angular resolution observations with the IRAM Plateau de Bure Interferometer
(PdBI) of the ortho-NH2D 1_{11}-1_{01} line at 85.926 GHz and compared them
with previously reported VLA NH3 data. We detected strong NH2D emission toward
the pre-protostellar cores identified in NH3 and dust emission, all located in
the vicinity of the UCHII region IRAS 20293+3952. We found high values of
Dfrac~0.1-0.8 in all the pre-protostellar cores and low values, Dfrac<0.1,
associated with young stellar objects. The high values of Dfrac in
pre-protostellar cores could be indicative of evolution, although outflow
interactions and UV radiation could also play a role.Comment: 5 pages, 3 figures. Accepted for publication in Astronomy and
Astrophysics Letter
Artificial Neural Network to predict mean monthly total ozone in Arosa, Switzerland
Present study deals with the mean monthly total ozone time series over Arosa,
Switzerland. The study period is 1932-1971. First of all, the total ozone time
series has been identified as a complex system and then Artificial Neural
Networks models in the form of Multilayer Perceptron with back propagation
learning have been developed. The models are Single-hidden-layer and
Two-hidden-layer Perceptrons with sigmoid activation function. After sequential
learning with learning rate 0.9 the peak total ozone period (February-May)
concentrations of mean monthly total ozone have been predicted by the two
neural net models. After training and validation, both of the models are found
skillful. But, Two-hidden-layer Perceptron is found to be more adroit in
predicting the mean monthly total ozone concentrations over the aforesaid
period.Comment: 22 pages, 14 figure
Three intermediate-mass YSOs with different properties emerging from the same natal cloud in IRAS 00117+6412
We observed with the VLA, PdBI, and SMA the centimeter and millimeter
continuum, N2H+(1-0), and CO(2-1) emission associated with a dusty cloud
harboring a nascent cluster with intermediate-mass protostars. At centimeter
wavelengths we found a strong source, tracing a UCHII region, at the eastern
edge of the dusty cloud, with a shell-like structure, and with the
near-infrared counterpart falling in the center of the shell. This is
presumably the most massive source of the forming cluster. About 15'' to the
west of the UCHII region and well embedded in the dusty cloud, we detected a
strong millimeter source, MM1, associated with centimeter and near-infrared
emission. MM1 seems to be driving a prominent high-velocity CO bipolar outflow,
and is embedded in a ridge of dense gas traced by N2H+. We estimated that MM1
is an intermediate-mass source in the Class 0/I phase. About 15'' to the south
of MM1, and still more deeply embedded in the dusty cloud, we detected a
compact millimeter source, MM2, with neither centimeter nor near-infrared
emission, but with water maser emission. MM2 is associated with a clump of
N2H+, whose kinematics reveal a clear velocity gradient and additionally we
found signposts of infall motions. MM2, being deeply embedded within the dusty
cloud, with an associated water maser but no hints of CO outflow emission, is
an intriguing object, presumably of intermediate mass. In conclusion, the UCHII
region is found at the border of a dusty cloud which is currently undergoing
active star formation. Two intermediate-mass protostars in the dusty cloud seem
to have formed after the UCHII region and have different properties related to
the outflow phenomenon.Comment: accepted to Astronomy and Astrophysic
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