8,156 research outputs found
Multi-wavelength differential astrometry of the S5 polar cap sample
We report on the status of our S5 polar cap astrometry program. Since 1997 we
have observed all the 13 radio sources of the complete S5 polar cap sample at
the wavelengths of 3.6 cm, 2 cm and 7 mm. Images of the radio sources at 3.6
and 2 cm have already been published reporting morphological changes.
Preliminary astrometric analyses have been carried out at three frequencies
with precisions in the relative position determination ranging from 80 to 20
microarcseconds. We report also on the combination of our phase-delay global
astrometry results with the microarcsecond-precise optical astrometry that will
be provided by future space-based instruments.Comment: 2 pages. 1 figure. Proceedings of the 7th European VLBI Network
Symposium held in Toledo, Spain on October 12-15, 2004. Editors: R.
Bachiller, F. Colomer, J.-F. Desmurs, P. de Vicente (Observatorio Astronomico
Nacional), p. 323-324. Needs evn2004.cl
Matrix product decomposition and classical simulation of quantum dynamics in the presence of a symmetry
We propose a refined matrix product state representation for many-body
quantum states that are invariant under SU(2) transformations, and indicate how
to extend the time-evolving block decimation (TEBD) algorithm in order to
simulate time evolution in an SU(2) invariant system. The resulting algorithm
is tested in a critical quantum spin chain and shown to be significantly more
efficient than the standard TEBD.Comment: 5 pages, 4 figure
A Sliding Mode Control Architecture for Human-Manipulator Cooperative Surface Treatment Tasks
© 2018 IEEE. This paper presents a control architecture readily suitable for surface treatment tasks such as polishing, grinding, finishing or deburring as carried out by a human operator, with the added benefit of accuracy, recurrence and physical strength as administered by a robotic manipulator partner. The shared strategy effectively couples the human operator propioceptive abilities and fine skills through his interactions with the autonomous physical agent. The novel proposed control scheme is based on task prioritization and a non-conventional sliding mode control, which is considered to benefit from its inherent robustness and low computational cost. The system relies on two force sensors, one located between the last link of the robot and the surface treatment tool, and the other located in some place of the robot end-effector: the former is used to suitably accomplish the conditioning task, while the latter is used by the operator to manually guide the robotic tool. When the operator chooses to cease guiding the tool, the robot motion safely switches back to an automatic reference tracking. The paper presents the theories for the novel collaborative controller, whilst its effectiveness for robotic surface treatment is substantiated by experimental results using a redundant 7R manipulator and a mock-up conditioning tool
1.6 GHz VLBI Observations of SN 1979C: almost-free expansion
We report on 1.6 GHz Very-Long-Baseline-Interferometry (VLBI) observations of
supernova SN 1979C made on 18 November 2002. We derive a model-dependent
supernova size. We also present a reanalysis of VLBI observations made by us on
June 1999 and by other authors on February 2005. We conclude that, contrary to
our earlier claim of strong deceleration in the expansion, SN 1979C has been
undergoing almost-free expansion (; ) for over
25 years.Comment: 4 pages, 4 figures; submitted to A&A on 14 May 2009. Accepted on 7
Jul 200
Automation of product packaging for industrial applications
[EN] This work presents a robotic-based solution devised to automate the product packaging in industrial environments. Although the proposed approach is illustrated for the case of the shoe industry, it applies to many other products requiring similar packaging processes. The main advantage obtained with the automated task is that productivity could be significantly increased. The key algorithms for the developed robot system are: object detection using a computer vision system; object grasping; trajectory planning with collision avoidance; and operator interaction using a force/torque sensor. All these algorithms have been experimentally tested in the laboratory to show the effectiveness and applicability of the proposed approach.This work has been partly supported by Ministerio de Economia y Competitividad of the Spanish Government [Grant No. RTC201654086 and PRI-AIBDE-2011-1219], by the Deutscher Akademischer Austauschdienst (DAAD) of the German Government (Projekt-ID 54368155) and by ROBOFOOT project [Grant No. 260159] of the European Commission.Perez-Vidal, C.; Gracia, L.; De Paco, J.; Wirkus, M.; Azorin, J.; De Gea, J. (2018). Automation of product packaging for industrial applications. International Journal of Computer Integrated Manufacturing. 31(2):129-137. https://doi.org/10.1080/0951192X.2017.1369165S12913731
IgE-Mediated Hypersensitivity Reactions to Cannabis in Laboratory Personnel
Background: There have been sporadic reports of hypersensitivity reactions to plants of the Cannabinaceae family (hemp and hops), but it has remained unclear whether these reactions are immunologic or nonimmunologic in nature. Objective: We examined the IgE-binding and histamine-releasing properties of hashish and marijuana extracts by CAP-FEIA and a basophil histamine release test. Methods: Two workers at a forensic laboratory suffered from nasal congestion, rbinitis, sneezing and asthmatic symptoms upon occupational contact with hashish or marijuana, which they had handled frequently for 25 and 16 years, respectively. Neither patient had a history of atopic disease. Serum was analyzed for specific IgE antibodies to hashish or marijuana extract by research prototype ImmunoCAP, and histamine release from basophils upon exposure to hashish or marijuana extracts was assessed. Results were matched to those of 4 nonatopic and 10 atopic control subjects with no known history of recreational or occupational exposure to marijuana or hashish. Results: Patient 1 had specific IgE to both hashish and marijuana (CAP class 2), and patient 2 to marijuana only (CAP class 2). Controls proved negative for specific IgE except for 2 atopic individuals with CAP class 1 to marijuana and 1 other atopic individual with CAP class 1 to hashish. Stimulation of basophils with hashish or marijuana extracts elicited histamine release from basophils of both patients and 4 atopic control subjects. Conclusions: Our results suggest an IgE-related pathomechanism for hypersensitivity reactions to marijuana or hashish. Copyright (C) 2011 S. Karger AG, Base
Comparison of retinal nerve fiber layer thinning and retinal ganglion cell loss after optic nerve transection in adult albino rats
We compared the time-course and magnitude of retinal nerve fiber layer (RNFL) thinning with that of retinal ganglion cell (RGC) loss after intraorbital optic nerve transection (IONT) in adult rats
Localization of serum resistance-associated protein in Trypanosoma brucei rhodesiense and transgenic Trypanosoma brucei brucei.
African trypanosomes infect a broad range of mammals, but humans and some higher primates are protected by serum trypanosome lytic factors that contain apolipoprotein L1 (ApoL1). In the human-infective subspecies of Trypanosoma brucei, Trypanosoma brucei rhodesiense, a gene product derived from the variant surface glycoprotein gene family member, serum resistance-associated protein (SRA protein), protects against ApoL1-mediated lysis. Protection against trypanosome lytic factor requires the direct interaction between SRA protein and ApoL1 within the endocytic apparatus of the trypanosome, but some uncertainty remains as to the precise mechanism and location of this interaction. In order to provide more insight into the mechanism of SRA-mediated resistance to trypanosome lytic factor, we assessed the localization of SRA in T. b. rhodesiense EATRO3 using a novel monoclonal antibody raised against SRA together with a set of well-characterized endosomal markers. By three-dimensional deconvolved immunofluorescence single-cell analysis, combined with double-labelling immunoelectron microscopy, we found that ≈ 50% of SRA protein localized to the lysosome, with the remaining population being distributed through the endocytic pathway, but apparently absent from the flagellar pocket membrane. These data suggest that the SRA/trypanolytic factor interaction is intracellular, with the concentration within the endosomes potentially crucial for ensuring a high efficiency.MN is funded by grants from the Spanish Ministerio de Ciencia e Innovación, (SAF2012-40029), Junta de Andalucia (CTS-5841) and VI PN de I+D+I 2008–2011, Instituto de Salud Carlos III – Subdirección General de Redes y Centros de Investigación Cooperativa (RICET) RD12/0018/0001 and RD12/0018/0015. J-MB is supported by a Miguel Servet Fellowship (CP09/00300) and funded by ‘Fondo de Investigación Sanitaria’ PI10/01128. JR and MC were funded by a Wellcome Trust Project Grant 093008/Z/10/Z. Work in the Dundee laboratory was funded by the Wellcome Trust (program grant 093008/Z/10/Z) and the Medical Research Council.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1111/cmi.1245
Experimental investigation of silicate-carbonate system at high pressure and high temperature
Melting and subsolidus relations in the (Mg,Fe)SiO3-(M,Fe)CO3, (Mg,Fe)(2)SiO4-(Mg,Fe)CO3, and (Mg,Fe)O-(Me,Fe)CO2 systems have been investigated at 14, 15, 16 and 25 GPa, 1973 K and 2173 K, using a 1000 t uniaxial multi anvil split sphere apparatus. The iron-magnesium partition coefficients between magnesite and silicates or oxides have been measured in subsolidus assemblages. Iron is always partitioned preferentially in the silicate and oxide phases, the order of increasing partitioning being pyroxene, olivine, silicate perovskite, wadsleyite and magnesiowustite. A thermodynamic model of iron-magnesium distribution between magnesite and all these phases, based on Gibbs free energy minimization, is established. Melting of pyroxene-magnesite and olivine-magnesite pseudo binary systems is eutectic, with eutectic points close to 1973 K and 60 mol % carbonate at 15 GPa in both systems. In the more complex mantle system, it is likely that such melts would form in the transition zone by heating and homogenization of deep subducted carbonates. The melts formed in the olivine-carbonate system are characterized by high Mg+Fe/Si ratios and thus unlikely to be primary kimberlitic magmas, a conclusion in agreement with previous studies in the peridotite-CO2 system, On the other hand, the observed pyroxene-magnesite melts formed at transition zone conditions have Mg+Fe/Si ratios that are comparable to those of natural kimberlites, suggesting that melting of carbonated pyroxenites at high pressures could be a source of kimberlitic magmas
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