346 research outputs found
Pose-estimation and control in a 3D visual servoing system
14th World Congress of IFAC, Beijing, China 1999The present work studies the case of a 3D visual servoing system composed by a robot manipulator, a CCD camera rigidly mounted on the end-effector of the robot, and other computer-based hardware. The aim of the system is to keep a desired relative position and orientation between the object and the camera, compensating for the autonomous object motion. Two existing algorithms for object's pose estimation have been implemented. Several controllers are designed and its performance evaluated along the paper
Valence band photoemission from the GaN(0001) surface
A detailed investigation by one-step photoemission calculations of the
GaN(0001)-(1x1) surface in comparison with recent experiments is presented in
order to clarify its structural properties and electronic structure. The
discussion of normal and off-normal spectra reveals through the identified
surface states clear fingerprints for the applicability of a surface model
proposed by Smith et al. Especially the predicted metallic bonds are confirmed.
In the context of direct transitions the calculated spectra allow to determine
the valence band width and to argue in favor of one of two theoretical bulk
band structures. Furthermore a commonly used experimental method to fix the
valence band maximum is critically tested.Comment: 8 pages, 11 eps files, submitted to PR
Fear of Loneliness: Development and Validation of a Brief Scale
Indexación: Scopus.This research aims to develop and validate a Spanish version of The Brief Scale of Fear of Loneliness (BSFL). Participants were 1385 youth and adults, 347 from a pilot sample and 1032 from the final version, whose ages were in the range of 18 to 40 years. Two instruments, the Rosenberg Self-Esteem Scale and the De Jong Gierveld Loneliness Scale, in their Peruvian versions, were used to support the relationship with other variables. Results show that the BSFL should be interpreted as a one-dimensional measure, the same ones that were examined at the exploratory level and verified at the confirmatory moment (RMSEA 0.95), and its reliability is considered good (ω > 0.88). In addition, the quality of the item content was reviewed by six expert judges for relevance and validity, with Aiken’s V being greater than 0.70. It is concluded that the BSFL is a valid and precise short instrument that can be used in future research studies. © Copyright © 2020 Ventura-León, Sánchez-Villena, Caycho-Rodríguez, Barboza-Palomino and Rubio.https://www.frontiersin.org/articles/10.3389/fpsyg.2020.583396/ful
Molecular epidemiology of seal parvovirus, 1988-2014
A novel parvovirus was discovered recently in the brain of a harbor seal (Phoca vitulina) with chronic meningo-encephalitis. Phylogenetic analysis of this virus indicated that it belongs to the genus Er
Seroprevalence of Antibodies against Seal Influenza A(H10N7) Virus in Harbor Seals and Gray Seals from the Netherlands
In the spring and summer 2014, an outbreak of seal influenza A(H10N7) virus infection occurred among harbor seals (Phoca vitulina) off the coasts of Sweden and Denmark. This virus subsequently spread to harbor seals off the coasts of Germany and the Netherlands. While thousands of seals were reported dead in Sweden, Denmark and Germany, only a limited number of seals were found dead in the Netherlands. To determine the extent of exposure of seals in the Netherlands to influenza A/H10N7 virus, we measured specific antibody titers in serum samples from live-captured seals and seals admitted for rehabilitation in the Netherlands by use of a hemagglutination inhibition assay and an ELISA. In harbor seals in 2015, antibodies against seal influenza A(H10N7) virus were detected in 41% (32 out of 78) pups, 10% (5 out of 52) weaners, and 58% (7 out of 12) subadults or adults. In gray seals (Halichoerus grypus) in 2015, specific antibodies were not found i
High throughput toxicity screening and intracellular detection of nanomaterials
EC FP7 NANoREG (Grant Agreement NMP4-LA-2013-310584)Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5215403/With the growing numbers of nanomaterials (NMs), there is a great demand for
rapid and reliable ways of testing NM safety—preferably using in vitro
approaches, to avoid the ethical dilemmas associated with animal research. Data
are needed for developing intelligent testing strategies for risk assessment of
NMs, based on grouping and read-across approaches. The adoption of high
throughput screening (HTS) and high content analysis (HCA) for NM toxicity
testing allows the testing of numerous materials at different concentrations and
on different types of cells, reduces the effect of inter-experimental variation, and
makes substantial savings in time and cost.info:eu-repo/semantics/publishedVersio
Density functional method for nonequilibrium electron transport
We describe an ab initio method for calculating the electronic structure,
electronic transport, and forces acting on the atoms, for atomic scale systems
connected to semi-infinite electrodes and with an applied voltage bias. Our
method is based on the density functional theory (DFT) as implemented in the
well tested Siesta approach (which uses non-local norm-conserving
pseudopotentials to describe the effect of the core electrons, and linear
combination of finite-range numerical atomic orbitals to describe the valence
states). We fully deal with the atomistic structure of the whole system,
treating both the contact and the electrodes on the same footing. The effect of
the finite bias (including selfconsistency and the solution of the
electrostatic problem) is taken into account using nonequilibrium Green's
functions. We relate the nonequilibrium Green's function expressions to the
more transparent scheme involving the scattering states. As an illustration,
the method is applied to three systems where we are able to compare our results
to earlier ab initio DFT calculations or experiments, and we point out
differences between this method and existing schemes. The systems considered
are: (1) single atom carbon wires connected to aluminum electrodes with
extended or finite cross section, (2) single atom gold wires, and finally (3)
large carbon nanotube systems with point defects.Comment: 18 pages, 23 figure
- …