17,813 research outputs found
Rotational modulation of the linear polarimetric variability of the cool dwarf TVLM 51346546
Aims: We aimed to monitor the optical linear polarimetric signal of the
magnetized, rapidly rotating M8.5 dwarf TVLM 51346546.
Methods: - and -band linear polarimetry images were collected with the
ALFOSC instrument of the 2.56-m Nordic Optical Telescope on two consecutive
nights covering about 0.5 and 4 rotation cycles in the and filters,
respectively. We also obtained simultaneous intensity curves by means of
differential photometry. The typical precision of the data is 0.46\%
(), 0.35\% () in the linear polarization degree and 9 mmag
(), 1.6 mmag () in the differential intensity curves.
Results: Strong and variable linear polarization is detected in the and
filters, with values of maximum polarization ( = 1.300.35 \%)
similar for both bands. The intensity and the polarimetric curves present a
sinusoid-like pattern with a periodicity of 1.98 h, which we ascribe to
structures in TVLM 51346's surface synchronized with rotation. We found that
the peaks of the intensity and polarimetric curves occur with a phase
difference of 0.180.01, and that the maximum of the linear polarization
happens nearly half a period (0.590.03) after the radio pulse. We
discussed different scenarios to account for the observed properties of the
light curves.Comment: Accepted for publication in Astronomy and Astrophysic
Simultaneous optical and near-infrared linear spectropolarimetry of the earthshine
Aims: We aim to extend our current observational understanding of the
integrated planet Earth spectropolarimetry from the optical to the
near-infrared wavelengths. Major biomarkers like O and water vapor
are strong flux absorbents in the Earth atmosphere and some linear polarization
of the reflected stellar light is expected to occur at these wavelengths.
Methods: Simultaneous optical ( m) and near-infrared (
m) linear spectropolarimetric data of the earthshine were acquired by
observing the nightside of the waxing Moon. The data have sufficient spectral
resolution (2.51 nm in the optical, and 1.83 and 2.91 nm in the near-infrared)
to resolve major molecular species present in the Earth atmosphere.
Results: We find the highest values of linear polarization () at
the bluest wavelengths, which agrees with the literature. Linear polarization
intensity steadily decreases towards red wavelengths reaching a nearly flat
value beyond 0.8 m. In the near-infrared, we measured a polarization
degree of for the continuum. We report the detection of molecular
features due to O at m and HO at 0.6530.725
m, 0.7800.825 m, 0.93 and 1.12 m in the spectropolarimetric
data; most of them show high linear polarimetry degrees above the continuum. In
particular, the broad HO 1.12 m band displays a polarimetric
intensity as high as that of the blue optical. These features may become a
powerful tool to characterize Earth-like planets in polarized light.Comment: 4 pages, 3 figures. Accepted for publication as Letter in Astronomy
and Astrophysics on 23/01/201
Spontaneous Raman scattering for simultaneous measurements of in-cylinder species
A technique for multi-species mole fraction measurement in internal combustion engines is described. The technique is based on the spontaneous Raman scattering. It can simultaneously provide the mole fractions of several species of N-2, O-2, H2O, CO2 and fuel. Using the system, simultaneous measurement of air/fuel ratio and burnt residual gas are carried out during the mixture process in a Controlled Auto Ignition (CAI) combustion engine. The accuracy and consistency of the measured results were confirmed by the measured air fuel ratio using an exhaust gas analyzer and independently calculated mole fraction values. Measurement of species mole fractions during combustion process has also been demonstrated. It shows that the SRS can provide valuable data on this process in a CAI combustion engine
When Imagining Yourself in Pain, Visual Perspective Matters : The Neural and Behavioral Correlates of Simulated Sensory Experiences
© 2015 Massachusetts Institute of TechnologyPeer reviewedPublisher PD
Statistical analysis of the owl:sameAs network for aligning concepts in the linking open data cloud
The massively distributed publication of linked data has brought to the attention of scientific community the limitations of classic methods for achieving data integration and the opportunities of pushing the boundaries of the field by experimenting this collective enterprise that is the linking open data cloud. While reusing existing ontologies is the choice of preference, the exploitation of ontology alignments still is a required step for easing the burden of integrating heterogeneous data sets. Alignments, even between the most used vocabularies, is still poorly supported in systems nowadays whereas links between instances are the most widely used means for bridging the gap between different data sets. We provide in this paper an account of our statistical and qualitative analysis of the network of instance level equivalences in the Linking Open Data Cloud (i.e. the sameAs network) in order to automatically compute alignments at the conceptual level. Moreover, we explore the effect of ontological information when adopting classical Jaccard methods to the ontology alignment task. Automating such task will allow in fact to achieve a clearer conceptual description of the data at the cloud level, while improving the level of integration between datasets. <br/
Innovation collaboration and appropriability by knowledge-intensive business services firms
We uncover a âparadox of formal appropriability mechanismsâ in the case of knowledge-intensive business services (KIBS) firms. Despite evidence that KIBS firms do not typically consider formal appropriability mechanisms, such as patents, to be central mechanisms for capturing value from innovation, we show that they are nevertheless important for their innovation collaboration. Drawing on an original survey of publicly-traded UK and US KIBS firms, we find a significant positive association between the importance of innovation collaboration and the importance of formal appropriability mechanisms. We interrogate the evidence for clients, as they are the most important partners for innovation collaboration. We find that the importance of innovation collaboration with clients goes hand-in-hand with the importance of formal appropriability mechanisms, although a negative relation appears when firms assign very high importance to formal appropriability mechanisms. Thus, modest levels of emphasis on formal appropriability mechanisms may prevent conflicts over ownership of jointly developed knowledge assets and knowledge leakages, while also avoiding the possibly negative effects of overly strict controls by legal departments on innovation collaboration. As well as exploring formal appropriability mechanisms, we also investigate the relationship between contractual and strategic appropriability mechanisms and innovation collaboration for KIBS firms
Capturing value from innovation in knowledge-intensive business service firms: the role of competitive strategy
Building on a problem-solving perspective to value creation and capture, and on the business strategy literature, we argue that the actions that knowledge-intensive business service (KIBS) firms take to identify, select and solve client problems will affect their approach to capturing value from innovation. We apply regression analysis to data from an original survey involving a sample of 230 innovations introduced by 150 publicly-traded UK and US KIBS firms. Distinguishing between cost- and differentiation-oriented KIBS firms, we find that cost-oriented firms tend to place more importance on all appropriability mechanisms than do differentiation-oriented firms. Furthermore, the perceived importance of formal appropriability mechanisms, relative to that of all appropriability mechanisms, tends to be higher for cost-oriented than for differentiation-oriented firms. This association is stronger for the case of the introduction of process (rather than product) innovation. These findings contribute to the strategy and service innovation literatures, by showing that KIBS firmsâ competitive strategies influence value capture, over and above the role of the innovation-, industry-, and institutional-level factors examined in earlier studies
Robust interferometer for the routing of light beams carrying orbital angular momentum
We have developed an interferometer requiring only minimal angular alignment for the routing of beams carrying orbital angular momentum. The MachâZehnder interferometer contains a Dove prism in each arm where each has a mirror plane around which the transverse phase profile is inverted. One consequence of the inversions is that the interferometer needs no alignment. Instead the interferometer defines a unique axis about which the input beam must be coupled. Experimental results are presented for the fringe contrast, reaching a maximum value of 93±1%
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