349 research outputs found
Deep Learning for Vanishing Point Detection Using an Inverse Gnomonic Projection
We present a novel approach for vanishing point detection from uncalibrated
monocular images. In contrast to state-of-the-art, we make no a priori
assumptions about the observed scene. Our method is based on a convolutional
neural network (CNN) which does not use natural images, but a Gaussian sphere
representation arising from an inverse gnomonic projection of lines detected in
an image. This allows us to rely on synthetic data for training, eliminating
the need for labelled images. Our method achieves competitive performance on
three horizon estimation benchmark datasets. We further highlight some
additional use cases for which our vanishing point detection algorithm can be
used.Comment: Accepted for publication at German Conference on Pattern Recognition
(GCPR) 2017. This research was supported by German Research Foundation DFG
within Priority Research Programme 1894 "Volunteered Geographic Information:
Interpretation, Visualisation and Social Computing
Metal and precursor effect during 1-heptyne selective hydrogenation using an activated carbon as support
Palladium, platinum, and ruthenium supported on activated carbon were used as catalysts for the selective hydrogenation of 1-heptyne, a terminal alkyne. All catalysts were characterized by temperature programmed reduction, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. TPR and XPS suggest that the metal in all catalysts is reduced after the pretreatment with H2 at 673 K. The TPR trace of the PdNRX catalyst shows that the support surface groups are greatly modified as a consequence of the use of HNO3 during the catalyst preparation. During the hydrogenation of 1-heptyne, both palladium catalysts were more active and selective than the platinum and ruthenium catalysts. The activity order of the catalysts is as follows: PdClRX > PdNRX > PtClRX ≫ RuClRX. This superior performance of PdClRX was attributed in part to the total occupancy of the d electronic levels of the Pd metal that is supposed to promote the rupture of the H2 bond during the hydrogenation reaction. The activity differences between PdClRX and PdNRX catalysts could be attributed to a better accessibility of the substrate to the active sites, as a consequence of steric and electronic effects of the superficial support groups. The order for the selectivity to 1-heptene is as follows: PdClRX = PdNRX > RuClRX > PtClRX, and it can be mainly attributed to thermodynamic effects.UNL and CONICET
Spectral aerosol optical depth retrievals by ground-based fourier transform infrared spectrometry
Aerosol Optical Depth (AOD) and the Ångström Exponent (AE) have been calculated in the near infrared (NIR) and short-wave infrared (SWIR) spectral regions over a period of one year (May 2019–May 2020) at the high-mountain Izaña Observatory (IZO) from Fourier Transform Infrared (FTIR) solar spectra. The high-resolution FTIR measurements were carried out coincidentally with Cimel CE318-T photometric observations in the framework of the Aerosol Robotic Network (AERONET). A spectral FTIR AOD was generated using two different approaches: by means of the selection of seven narrow FTIR micro-windows (centred at 1020.90, 1238.25, 1558.25, 1636.00, 2133.40, 2192.00, and 2314.20 nm) with negligible atmospheric gaseous absorption, and by using the CE318-AERONET’s response function in the near-coincident bands (1020 nm and 1640 nm) to degrade the high-resolution FTIR spectra. The FTIR system was absolutely calibrated by means of a continuous Langley–Plot analysis over the 1-year period. An important temporal drift of the calibration constant was observed as a result of the environmental exposure of the FTIR’s external optical mirrors (linear degradation rate up to 1.75% month−1). The cross-validation of AERONET-FTIR databases documents an excellent agreement between both AOD products, with mean AOD differences below 0.004 and root-mean-squared errors below 0.006. A rather similar agreement was also found between AERONET and FTIR convolved bands, corroborating the suitability of low-resolution sunphotometers to retrieve high-quality AOD data in the NIR and SWIR domains. In addition, these results demonstrate that the methodology developed here is suitable to be applied to other FTIR spectrometers, such as portable and low-resolution FTIR instruments with a potentially higher spatial coverage. The spectral AOD dependence for the seven FTIR micro-windows have been also examined, observing a spectrally flat AOD behaviour for mineral dust particles (the typical atmospheric aerosols presented at IZO). A mean AE value of 0.53 ± 0.08 for pure mineral dust in the 1020–2314 nm spectral range was retrieved in this paper. A subsequent cross-validation with the MOPSMAP (Modeled optical properties of ensembles of aerosol particles) package has ensured the reliability of the FTIR dataset, with AE values between 0.36 to 0.60 for a typical mineral dust content at IZO of 100 cm and water-soluble particle (WASO) content ranging from 600 to 6000 cm. The new database generated in this study is believed to be the first long-term time series (1-year) of aerosol properties generated consistently in the NIR and SWIR ranges from ground-based FTIR spectrometry. As a consequence, the results presented here provide a very promising tool for the validation and subsequent improvement of satellite aerosol products as well as enhance the sensitivity to large particles of the existing databases, required to improve the estimation of the aerosols’ radiative effect on climate
Assessment of nocturnal aerosol optical depth from lunar photometry at the Izaña high mountain observatory
This work is a first approach to correct the systematic errors
observed in the aerosol optical depth (AOD) retrieved at nighttime using
lunar photometry and calibration techniques dependent on the lunar irradiance
model. To this end, nocturnal AOD measurements were performed in 2014 using
the CE318-T master Sun–sky–lunar photometer (lunar Langley calibrated) at
the Izaña high mountain observatory. This information has been restricted to 59
nights characterized as clean and stable according to lidar vertical
profiles. A phase angle dependence as well as an asymmetry within the Moon's
cycle of the Robotic Lunar Observatory (ROLO) model could be deduced from the comparison in this
59-night period of the CE318-T calibration performed by means of the
lunar Langley calibration
and the calibration performed every single night by means of
the common Langley technique. Nocturnal AOD has also been compared in the
same period with a reference AOD based on daylight AOD extracted from the
AErosol RObotic NETwork (AERONET) at the same station. Considering stable conditions, the
difference ΔAODfit, between AOD from lunar observations
and the linearly interpolated AOD (the reference) from daylight data, has
been calculated. The results show that ΔAODfit values are
strongly affected by the Moon phase and zenith angles. This dependency has been
parameterized using an empirical model with two independent variables (Moon
phase and zenith angles) in order to correct the AOD for these residual
dependencies. The correction of this parameterized dependency has been
checked at four stations with quite different environmental conditions
(Izaña, Lille, Carpentras and Dakar) showing a significant reduction of the
AOD dependence on phase and zenith angles and an improved agreement with
daylight reference data. After the correction, absolute AOD differences for
day–night–day clean and stable transitions remain below 0.01 for all
wavelengths
El periodismo en el espejo. La profesión analizada por periodistas andaluces
La organización profesional, la precariedad laboral, las presiones de los propios medios, la ética de los profesionales a la hora de elaborar la información o su sensibilidad frente a los problemas sociales, fueron los ejes de la entrevista en profundidad realizada a veinticuatro periodistas andaluces para reflexionar en voz alta sobre su propia profesión en nuestra sociedad. En este artículo explicamos los motivos de nuestra investigación y las cuestiones más relevantes que se pusieron de manifiesto en sus discursos
Effectiveness of a Comprehensive Health Literacy Consultation Skills Training for Undergraduate Medical Students:A Randomized Controlled Trial
Comprehensible communication by itself is not sufficient to overcome health literacy related problems. Future doctors need a larger scope of capacities in order to strengthen a patient's autonomy, participation, and self-management abilities. To date, such comprehensive training-interventions are rarely embedded in curricula, nor systematically evaluated. We assessed whether comprehensive training increased these health literacy competencies, in a randomized controlled trial (RCT), with a waiting list condition. Participants were international undergraduate medical students of a Dutch medical faculty (intervention: 39; control: 40). The 11-h-training-intervention encompassed a health literacy lecture and five interactive small-group sessions to practise gathering information and providing comprehensible information, shared decision-making, and enabling of self-management using role-play and videotaped conversations. We assessed self-reported competencies (knowledge and awareness of health literacy, attitude, self-efficacy, and ability to use patient-centred communication techniques) at baseline, after a five and ten-week follow-up. We compared students' competencies using multi-level analysis, adjusted for baseline. As validation, we evaluated demonstrated skills in videotaped consultations for a subsample. The group of students who received the training intervention reported significantly greater health literacy competencies, which persisted up to five weeks afterwards. Increase was greatest for providing comprehensible information (B: 1.50; 95% confidence interval, CI 1.15 to 1.84), shared decision-making (B: 1.08; 95% CI 0.60 to 1.55), and self-management (B: 1.21; 95% CI 0.61 to 1.80). Effects regarding demonstrated skills confirmed self-rated competency improvement. This training enhanced a larger scope of health literacy competences and was well received by medical students. Implementation and further evaluation of this training in education and clinical practice can support sustainable health literacy capacity building of future doctors and contribute to better patient empowerment and outcomes of consultations
Light conditions and heterogeneity in illumination affect growth and survival of Octopus vulgaris paralarvae reared in the hatchery
In order to succeed in common octopus (Octopus vulgaris) aquaculture, it is necessary to overcome the massive paralarval mortalities, which are likely related to zootechnical and/or nutritional aspects. Among the zootechnical aspects, the effect of light could be vital for the development of paralarvae given their sophisticated visual system. O. vulgaris paralarvae display vertical behavior in the wild, being in deeper waters during the day and close to the surface at night. For this reason, the present study traces a collection of light assays in captivity, to test ecologically-driven hypotheses on the growth and survival of octopus paralarvae. The first assay tested a factorial combination of light colors (blue vs white) and intensity (low ~13 lx (36 W/m2), medium ~87 lx (151 W/m2) and high ~265 lx (422 W/m2)). The results pointed to a significant negative impact of low light intensities (13 and 87 lx) on paralarval growth. The second assay was designed to contrast light colors (blue vs white), different levels of intensities (300 lx (478 W/m2) vs 600 lx (1077 W/m2)) and partial coverage of the tanks using a shade mesh, named as “shadow zone” (half-covered vs non-covered tanks). In half-covered tanks, survival was significantly improved, with the best results coming from half-covered tanks with blue light and 600 lx, but no differences in dry weight were observed. The third experiment tested a factor called “light source position” with two levels: “Control” when the light incidence angle was 0° with respect to the normal direction (i.e. perpendicular to the water surface), and “Oblique” when the light incidence angle was 60° with respect to the normal direction. In this experiment, survival significantly improved under oblique light but no differences in dry weight were detected. The last experiment was an unifactorial design combining “light source position” and “tank partial coverage” with three treatments: i) control light with uncovered tanks, ii) oblique light with uncovered tanks, iii) control light with semi-covered tanks. Oblique light with uncovered tanks was associated with a higher survival rate but without statistical significance, probably due to data variability. It can be concluded that light intensity tended to affect paralarval dry weight, whereas the existence of a shadow zone or oblique light are more related with an improvement of survival rate
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