Mononchid nematodes from Spain : six known species and Miconchus baeticus sp. n. occurring in southern fir forests

Cet article traite de nématodes Mononchides présents dans les forêts de sapins (#Abies pinsapo Boiss.) d'Espagne méridionale et donne la description et l'illustration d'une nouvelle espèces, #Miconchus baeticus sp. n., collectée dans une zone naturelle protégée (Sierra de las Nieves). #M. baeticus$est principalement caractérisé par les dents dorsale et ventrosublatérales en position suprabasale, les dents de remplacement toujours présentes chez l'adulte à l'intérieur des dents fonctionnelles, les apex des dents localisés à 31-42$, #Coomansus parvus, #Prionchulus muscorum, #Mylonchulus brachyuris, #Anatonchus ginglymodontus et #Miconchus studeri$ sont également signalés. (Résumé d'auteur

The occurrence and distribution of Xiphinema species (Nematoda : Dorylaimida) in spanish fir woodlands

Une étude comparative a été réalisée en vue de définir l'influence des facteurs édaphiques sur la présence et l'abondance relative de quatre espèces de #Xiphinema observées dans le sol de cinq forêts de sapin (#Abies pinsapo Boiss) du sud de l'Espagne. Les prélèvements ont été effectués de façon saisonnière pendant une année. Afin de relier la présence des espèces avec les caractéristiques de l'habitat et mettre en évidence leur mode de répartition dans les aires étudiées, les méthodes d'analyses univariées (analyse linéaire de la variance) et multivariées (analyses en grappe et de correspondance) ont été utilisées. La répartition de trois des espèces s'est révélée correspondre aux gradients de texture du sol. #X. sphaerocephalum montre ses plus grandes fréquence et abondance relative dans les sols à roche-mère calcaire, mais n'a pas été trouvé sur les péridotites, c'est-à-dire dans des sols plus sableux, préférant les textures plutôt limoneuses. #X. pachtaicum est rencontré dans les sols à texture argileuse plus nettement soumis aux conditions climatiques méditerranéennes. La répartition de #X. diversicaudatum est très nettement liée aux sols acides de texture plus sableuse avec un taux élevé d'argile fine. #X. turcicum, enfin, n'est rencontré que très rarement et en faible nombre, aussi sa répartition dans ces sols demeure-t-elle obscure. (Résumé d'auteur

Biomechanical and histological analysis of titanium (machined and treated surface) versus zirconia implant materials: an in vivo animal study

This article belongs to the Special Issue Clinical Implants and the Biocompatibility of Biodegradable BiomaterialsObjectives: The aim of this study was to perform an in vivo histological comparative evaluation of bone formation around titanium (machined and treated surface) and zirconia implants. For the present study were used 50 commercially pure titanium implants grade IV, being that 25 implants with a machined surface (TiM group), 25 implants with a treated surface (TiT group) and, 25 implants were manufactured in pure zirconia (Zr group). The implants (n = 20 per group) were installed in the tibia of 10 rabbits. The implants distribution was randomized (n = 3 implants per tibia). Five implants of each group were analyzed by scanning electron microscopy and an optical laser profilometer for surface roughness characterization. Six weeks after the implantation, 10 implants for each group were removed in counter-torque for analysis of maximum torque value. The remaining samples were processed, included in historesin and cut to obtain non-decalcified slides for histomorphological analyses and histomorphometric measurement of the percentage of bone-implant contact (BIC%). Comparisons were made between the groups using a 5% level of significance (p < 0.05) to assess statistical differences. The results of removal torque values (mean ± standard deviation) showed for the TiM group 15.9 ± 4.18 N cm, for TiT group 27.9 ± 5.15 N cm and for Zr group 11.5 ± 2.92 N cm, with significant statistical difference between the groups (p < 0.0001). However, the BIC% presented similar values for all groups (35.4 ± 4.54 for TiM group, 37.8 ± 4.84 for TiT group and 34.0 ± 6.82 for Zr group), with no statistical differences (p = 0.2171). Within the limitations of the present study, the findings suggest that the quality of the new bone tissue formed around the titanium implants present a superior density (maturation) in comparison to the zirconia implants

Changes in the trajectory of the radio jet in 0735+178?

We present multi-epoch 8.4 and 43 GHz Very Long Baseline Array images of the BL Lac object 0735+178. The images confirm the presence of a twisted jet with two sharp apparent bends of 90$^{\circ}$ within two milliarcseconds of the core, resembling a helix in projection. The observed twisted geometry could be the result of precession of the jet inlet, but is more likely produced by pressure gradients in the external medium through which the jet propagates. Quasi-stationary components are observed at the locations of the 90$^{\circ}$ bends, possibly produced by differential Doppler boosting. Identification of components across epochs, since the earliest VLBI observations of this source in 1979.2, proves difficult due to the sometimes large time gaps between observations. One possible identification suggests the existence of superluminal components following non--ballistic trajectories with velocities up to $11.6\pm 0.6 h_{65}^{-1} c$. However, in images obtained after mid-1995, components show a remarkable tendency to cluster near several jet positions, suggesting a different scenario in which components have remained nearly stationary in time at least since mid-1995. Comparison with the earlier published data, covering more than 19 years of observations, suggests a striking qualitative change in the jet trajectory sometime between mid-1992 and mid-1995, with the twisted jet structure with stationary components becoming apparent only at the later epochs. This would require a re-evaluation of the physical parameters estimated for 0735+178, such as the observing viewing angle, the plasma bulk Lorentz factor, and those deduced from these.Comment: 18 pages, 5 figures, accepted for publication in MNRA

The milliarcsecond-scale radio structure of AB Doradus A

Context. The fast rotator, pre-main sequence star AB Dor A is a strong and persistent radio emitter. The extraordinary coronal flaring activity is thought to be the origin of compact radio emission and other associated phenomena, such as large slingshot prominences. Aims. We aim to investigate the radio emission mechanism and the milliarcsecond radio structure around AB Dor A. Methods. We performed phase-referenced VLBI observations at 22.3 GHz, 8.4 GHz, and 1.4 GHz over more than one decade using the Australian VLBI array. Results. Our 8.4 GHz images show a double core-halo morphology, similar at all epochs, with emission extending at heights between 5 and 18 stellar radii. Furthermore, the sequence of the 8.4 GHz maps shows a clear variation of the source structure within the observing time. However, images at 1.4 GHz and 22.3 GHz are compatible with a compact source. The phase-reference position at 8.4 GHz and 1.4 GHz are coincident with those expected from the well-known milliarcsecond-precise astrometry of this star, meanwhile the 22.3 GHz position is 4σ off the prediction in the north-west direction. The origin of this offset is still unclear. Conclusions. We have considered several models to explain the morphology and evolution of the inner radio structure detected in AB Dor A. These models include emission from the stellar polar caps, a flaring, magnetically-driven loop structure, and the presence of helmet streamers. We also investigated a possible close companion to AB Dor A. Our results confirm the extraordinary coronal magnetic activity of this star, capable of producing compact radio structures at very large heights that have so far only been seen in binary interacting systems.J.B.C., R.A., J.C.G., and J.M.M. were partially supported by the Spanish MINECO projects AYA2012-38491-C02-01, AYA2015-63939- C2-2-P, PGC2018-098915-B-C22 and by the Generalitat Valenciana projects PROMETEO/2009/104 and PROMETEOII/2014/05

Physics demos for all UVEG degrees: a unique project in Spain

The Physics Demo Project at the University of Valencia (www.uv.es/fisicademos) has developed a collection of physics demonstrations to be used during lectures. It consists of more than 130 experimental demos about different physics topics. More than 30 professors borrow them whenever they lecture on physics in any of our 40 courses in 17 different science or technical degrees, involving 246 ECTS and more than 3500 students. Each demo kit with a simple experimental set displays a particular physics phenomenon. An on-line user guide highlights the main physics principles involved, instructions on how to use it and advices of how to link it to the theoretical concepts or to technical applications. Demo lectures (and collections) are a usual and widespread practice in many countries but not in Spain. This unique initiative aims at the recovery of this practice by involving a growing collaborative team of users and with the aid of educational innovation projects. Here we explain the project content, organization and recent developments. Our experience, together with the positive students comments, allows us to draw the following conclusions: demos introduce the real sensible world in the lecture hall, providing the necessary link between concepts and everyday life, and becoming, again, something more than "chalk and talk"

Radio-Size Estimates of SN 1993J

Supernova 1993J (SN 1993J) in M81, now classified as Type IIb, is a strongly emitting radio supernova whose size can be resolved and whose growth can be monitored with the technique of very long baseline interferometry (VLBI). The results could provide important information about the circumstellar matter and the degree of asymmetry of the explosion. For several models of the emission of the radio supernova, we report estimates of its angular sizes 29 and 36 days after explosion at the wavelengths of 3.6 and 1.3 cm, respectively. These results, which correspond to our first epochs in an ongoing effort to determine the supernova structure and its growth, slightly favor an optically thick uniform disk model, given the recently derived Cepheid distance to M81 and the estimated maximum supernova expansion speed. Further VLBI observations, combined with the expansion-speed data, may yield an independent estimate of the distance to M81.This work was supported in part by the Spanish DGICYT grant PB89-009 and in part by NSF grant AST 9303527. We thank Kurt Weiler for a very careful review of this paper and N. Renzetti and P. Wolken for their extraordinary efforts in arranging for our use of the DSN antenn

Evaluation of night-time aerosols measurements and lunar irradiance models in the frame of the first multi-instrument nocturnal intercomparison campaign

The first multi-instrument nocturnal aerosol optical depth (AOD) intercom-parison campaign was held at the high-mountain Iza ̃na Observatory (Tener-ife, Spain) in June 2017, involving 2-minutes synchronous measurements fromtwo different types of lunar photometers (Cimel CE318-T and Moon Preci-sion Filter Radiometer, LunarPFR) and one stellar photometer. The Robotic Lunar Observatory (ROLO) model developed by the U.S. Geological Survey(USGS) was compared with the open-access ROLO Implementation for Moonphotometry Observation (RIMO) model. Results showed rather small differ-ences at Iza ̃na over a 2-month time period covering June and July, 2017(±0.01 in terms of AOD calculated by means of a day/night/day coherencetest analysis and±2 % in terms of lunar irradiance). The RIMO model hasbeen used in this field campaign to retrieve AOD from lunar photometricmeasurements. No evidence of significant differences with the Moon’s phase angle wasfound when comparing raw signals of the six Cimel photometers involved inthis field campaign.The raw signal comparison of the participating lunar photometers (Cimeland LunarPFR) performed at coincident wavelengths showed consistent mea-surements and AOD differences within their combined uncertainties at 870 nmand 675 nm. Slightly larger AOD deviations were observed at 500 nm, point-ing to some unexpected instrumental variations during the measurement pe-riod.Lunar irradiances retrieved using RIMO for phase angles varying between0◦and 75◦(full Moon to near quarter Moon) were compared to the irradi-ance variations retrieved by Cimel and LunarPFR photometers. Our resultsshowed a relative agreement within±3.5 % between the RIMO model andthe photometer-based lunar irradiances.The AOD retrieved by performing a Langley-plot calibration each nightshowed a remarkable agreement (better than 0.01) between the lunar pho-tometers. However, when applying the Lunar-Langley calibration using RIMO,AOD differences of up to 0.015 (0.040 for 500 nm) were found, with differ-ences increasing with the Moon’s phase angle. These differences are thoughtto be partly due to the uncertainties in the irradiance models, as well asinstrumental deficiencies yet to be fully understood.High AOD variability in stellar measurements was detected during thecampaign. Nevertheless, the observed AOD differences in the Cimel/stellarcomparison were within the expected combined uncertainties of these twophotometric techniques. Our results indicate that lunar photometry is amore reliable technique, especially for low aerosol loading conditions.The uncertainty analysis performed in this paper shows that the com-bined standard AOD uncertainty in lunar photometry is dependent on thecalibration technique (up to 0.014 for Langley-plot with illumination-basedcorrection, 0.012-0.022 for Lunar-Langley calibration, and up to 0.1 for the 2 Sun-Moon Gain Factor method). This analysis also corroborates that theuncertainty of the lunar irradiance model used for AOD calculation is withinthe 5-10 % expected range.This campaign has allowed us to quantify the important technical diffi-culties that still exist when routinely monitoring aerosol optical propertiesat night-time. The small AOD differences observed between the three typesof photometers involved in the campaign are only detectable under pristinesky conditions such as those found in this field campaign. Longer campaignsare necessary to understand the observed discrepancies between instrumentsas well as to provide more conclusive results about the uncertainty involvedin the lunar irradiance model

Radio emission in a nearby, ultra-cool dwarf binary: A multifrequency study

Context. The substellar triple system VHS J125601.92−125723.9 (hereafter VHS 1256−1257) is composed of an equal-mass M7.5 brown dwarf binary and an L7 low-mass substellar object. In Guirado et al. (2018, A&A, 610, A23) we published the detection of radio emission at 8.4 GHz coming from the central binary and making it an excellent target for further observations. Aims. We aim to identify the origin of the radio emission occurring in the central binary of VHS 1256−1257 while discussing the expected mechanisms involved in the radio emission of ultra-cool dwarfs. Methods. We observed this system with the Karl G. Jansky Very Large Array, the European very-long-baseline interferometry (VLBI) Network, the enhanced Multi-Element Remotely Linked Interferometer Network, the NOrthern Extended Millimeter Array, and the Atacama Large Millimetre Array at frequencies ranging from 5 GHz up to 345 GHz in several epochs during 2017, 2018, and 2019. Results. We found radio emission at 6 GHz and 33 GHz coincident with the expected position of the central binary of VHS 1256−1257. The Stokes I density fluxes detected were 73 ± 4 μJy and 83 ± 13 μJy, respectively, with no detectable circular polarisation or pulses. No emission is detected at higher frequencies (230 GHz and 345 GHz), nor at 5 GHz with VLBI arrays. The emission appears to be stable over almost three years at 6 GHz. To explain the constraints obtained both from the detections and non-detections, we considered multiple scenarios including thermal and nonthermal emission, and different contributions from each component of the binary. Conclusions. Our results can be well explained by nonthermal gyrosynchrotron emission originating at radiation belts with a low plasma density (ne = 300−700 cm−3), a moderate magnetic field strength (B ≈ 140 G), and an energy distribution of electrons following a power-law (dN/dE ∝ E−δ) with δ fixed at 1.36. These radiation belts would need to be present in both components and also be viewed equatorially. © ESO 2022.We sincerely thank the anonymous referee for his/her very useful and constructive criticisms and suggestions. This paper is based on observations carried out with the IRAM NOEMA interferometer and the IRAM 30-m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). JBC and JCG were partially supported by the Spanish MINECO projects AYA2015-63939-C2-2-P, PGC2018-098915-B-C22 and by the Generalitat Valenciana project GVPROMETEO2020−080. MPT acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and through grants PGC2018-098915-B-C21 and PID2020-117404GB-C21 (MCI/AEI/FEDER, UE). RA was supported by the Generalitat Valenciana postdoctoral grant APOSTD/2018/177. BG acknowledges support from the UK Science and Technology Facilities Council (STFC) via the Consolidated Grant ST/R000905/1. MRZO and VJSB acknowledge the financial support from PID2019-109522GB-C51 and PID2019-109522GB-C53, respectively.Peer reviewe

The large trans-Neptunian object 2002 TC302 from combined stellar occultation, photometry, and astrometry data

Context. Deriving physical properties of trans-Neptunian objects is important for the understanding of our Solar System. This requires observational efforts and the development of techniques suitable for these studies. Aims. Our aim is to characterize the large trans-Neptunian object (TNO) 2002 TC302. Methods. Stellar occultations offer unique opportunities to determine key physical properties of TNOs. On 28 January 2018, 2002 TC302 occulted a mv ~ 15.3 star with designation 593-005847 in the UCAC4 stellar catalog, corresponding to Gaia source 130957813463146112. Twelve positive occultation chords were obtained from Italy, France, Slovenia, and Switzerland. Also, four negative detections were obtained near the north and south limbs. This represents the best observed stellar occultation by a TNO other than Pluto in terms of the number of chords published thus far. From the 12 chords, an accurate elliptical fit to the instantaneous projection of the body can be obtained that is compatible with the near misses. Results. The resulting ellipse has major and minor axes of 543 ± 18 km and 460 ± 11 km, respectively, with a position angle of 3 ± 1 degrees for the minor axis. This information, combined with rotational light curves obtained with the 1.5 m telescope at Sierra Nevada Observatory and the 1.23 m telescope at Calar Alto observatory, allows us to derive possible three-dimensional shapes and density estimations for the body based on hydrostatic equilibrium assumptions. The effective diameter in equivalent area is around 84 km smaller than the radiometrically derived diameter using thermal data from Herschel and Spitzer Space Telescopes. This might indicate the existence of an unresolved satellite of up to ~300 km in diameter, which is required to account for all the thermal flux, although the occultation and thermal diameters are compatible within their error bars given the considerable uncertainty of the thermal results. The existence of a potential satellite also appears to be consistent with other ground-based data presented here. From the effective occultation diameter combined with absolute magnitude measurements we derive a geometric albedo of 0.147 ± 0.005, which would be somewhat smaller if 2002 TC302 has a satellite. The best occultation light curves do not show any signs of ring features or any signatures of a global atmosphere.Funding from Spanish projects AYA2014-56637-C2-1-P, AYA2017-89637-R, from FEDER, and Proyecto de Excelencia de la Junta de Andalucía 2012-FQM1776 is acknowledged. We would like to acknowledge financial support by the Spanish grant AYA-RTI2018-098657-JI00 “LEO-SBNAF” (MCIU/AEI/FEDER, UE) and the financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV- 2017-0709). Part of the research received funding from the European Union’s Horizon 2020 Research and Innovation Programme, under grant agreement no. 687378 and from the ERC programme under Grant Agreement no. 669416 Lucky Star. The following authors acknowledge the respective CNPq grants: FB-R 309578/2017-5; RV-M 304544/2017-5, 401903/2016-8; J.I.B.C. 308150/2016-3; MA 427700/2018-3, 310683/2017-3, 473002/2013-2. This study was financed in part by the Coordenação de Aperfeiaçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001 and the National Institute of Science and Technology of the e-Universe project (INCT do e-Universo, CNPq grant 465376/2014-2). GBR acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016, MA FAPERJ grant E-26/111.488/2013 and ARGJr FAPESP grant 2018/11239-8. E.F.-V. acknowledges support from the 2017 Preeminent Postdoctoral Program (P3) at UCF. C.K., R.S., A.F-T., and G.M. have been supported by the K-125015 and GINOP-2.3.2-15-2016-00003 grants of the Hungarian National Research, Development and Innovation Office (NKFIH), Hungary. G.M. was also supported by the Hungarian National Research, Development and Innovation Office (NKFIH) grant PD-128 360. R.K. and T.P. were supported by the VEGA 2/0031/18 grant