3,347 research outputs found
Study of the genetic homogeneity of Albarino (Vitis vinifera L.) growing in Galicia (Spain) using isozyme and RAPD markers
Research NoteAn evaluation of the genetic diversity of cv. Albarino (Vitis vinifera L.) was carried out. Centenarian and young plants were selected from vineyards, some of them showing slight ampelographic differences. Using ELISA tests 5 out of 24 plants were found to be infected with grapevine leafroll-associated virus 3 (GLRaV-3). In order to evaluate genetic polymorphism, 10 enzyme systems and 42 RAPD primers were used. The 73 isozyme and 308 RAPD markers were common in the samples tested. The results show the existence of a genetic homogeneity within Albarino cultivated in Galicia. Minor ampelographic differences among samples could be due to external factors rather than to genetic differences
Coordinated thermal and optical observations of Trans-Neptunian object (20000) Varuna from Sierra Nevada
We report on coordinated thermal and optical measurements of trans-Neptunian
object (20000) Varuna obtained in January-February 2002, respectively from the
IRAM 30-m and IAA 1.5 m telescopes. The optical data show a lightcurve with a
period of 3.176+/-0.010 hr, a mean V magnitude of 20.37+/-0.08 and a
0.42+/-0.01 magnitude amplitude. They also tentatively indicate that the
lightcurve is asymmetric and double-peaked. The thermal observations indicate a
1.12+/-0.41 mJy flux, averaged over the object's rotation. Combining the two
datasets, we infer that Varuna has a mean 1060(+180/-220) km diameter and a
mean 0.038(+0.022/-0.010) V geometric albedo, in general agreement with an
earlier determination using the same technique.Comment: Accepted for publication in Astronomy & Astrophysics (7 pages,
including 3 figures
Fast, broad-band magnetic resonance spectroscopy with diamond widefield relaxometry
We present an alternative to conventional Electron Paramagnetic Resonance
spectroscopy equipment. Avoiding the use of bulky magnets and magnetron
equipment, we use the photoluminescence of an ensemble of Nitrogen-Vacancy
centers at the surface of a diamond. Monitoring their relaxation time (or T1),
we detected their cross-relaxation with the compound of interest. In addition,
the EPR spectra is encoded through a localized magnetic field gradient. While
12 minutes was necessary to record each data point of the spectrum with
previous individual NV center's technics, we are able to reconstruct a full
spectrum at once in 3 seconds, over a range from 3 to 11 gauss. In term of
sensitivity, only 0.5 microliter of a hexaaquacopper (II) ion solution with 1
micromole per liter concentration was necessary.Comment: Main text (15 pages, 6 Figures) + Supplementary (6 Pages, 7 Figures
Diamond Color Centers in Diamonds for Chemical and Biochemical Analysis and Visualization
Beyond the sparkle, other properties of diamond havegained increasing attention in the past few decades amongchemists and physicists. Color centers-impurities formed byone or a few foreign atoms or vacancies in the diamondlattice-are one reason for this. While pure diamond istransparent, the presence of color centers causes changes incoloration. Color centers introduce additional electronic statesin the wide band gap of diamond, giving rise to transitions thatabsorb and emit light in the visible spectrum
Geochemical influence of soil on leaf and grape (Vitis vinifera L. 'Cencibel') composition in La Mancha region (Spain)
The main purpose of the study was to evaluate major and trace elements contained in topsoil from representative plots of vineyards located in La Mancha, Spain, to obtain an elemental fingerprint of vines. The samples evaluated were obtained from topsoil in six different plots, belonging to the region of La Mancha, characterized by the cultivation of vineyards (near 189.127 ha). Twenty different vines from each plot were chosen to take samples from grapes, petioles and leaves. Analyses were carried out by X-ray Fluorescence applied on soils and dried vegetal matter. Biological Absorption Coefficient (BAC) was calculated to assess the uptake of minerals by vines as a function of their specific content in soil. The BAC in leaves and grapes was very similar for all studied elements. High contents of Ca, Sr, Ni and rare earth elements (La, Ce and Nd) were found along with low contents in Al, Zr, Ba, Cu, Zn and Pb, and normal contents in the rest of the elements. BAC in grapes was lower for the majority of the studied elements but it is interesting to underline the contents of Cs, K, Nb, Ce, Zn and Sr as possible markers of soil fingerprinting in the resulting wines.
Pressure-induced phase-transition sequence in CoF2: An experimental and first-principles study on the crystal, vibrational, and electronic properties
We report a complete structural study of CoF2 under pressure. Its crystal structure and vibrational and electronic properties have been studied both theoretically and experimentally using first-principles density functional theory (DFT) methods, x-ray diffraction, x-ray absorption at Co K-edge experiments, Raman spectroscopy, and optical absorption in the 0–80 GPa range. We have determined the structural phase-transition sequence in CoF2 and corresponding transition pressures. The results are similar to other transition-metal difluorides such as FeF2 but different to ZnF2 and MgF2, despite that the Co2+ size (ionic radius) is similar to Zn2+ and Mg2+. We found that the complete phase-transition sequence is tetragonal rutile (P42/mnm) → CaCl2 type (orthorhombic Pnnm) → distorted PdF2 (orthorhombic Pbca)+PdF2 (cubic Pa3¯) in coexistence → fluorite (cubic Fm3¯m) → cotunnite (orthorhombic Pnma). It was observed that the structural phase transition to the fluorite at 15 GPa involves a drastic change of coordination from sixfold octahedral to eightfold cubic with important modifications in the vibrational and electronic properties. We show that the stabilization of this high-pressure cubic phase is possible under nonhydrostatic conditions since ideal hydrostaticity would stabilize the distorted-fluorite structure (tetragonal I4/mmm) instead. Although the first rutile → CaCl2-type second-order phase transition is subtle by Raman spectroscopy, it was possible to define it through the broadening of the Eg Raman mode which is split in the CaCl2-type phase. First-principles DFT calculations are in fair agreement with the experimental Raman mode frequencies, thus providing an accurate description for all vibrational modes and elastic properties of CoF2 as a function of pressure
New young planetary nebulae in IPHAS
Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory. DOI: 10.1051/0004-6361/200811575Aims. We search for very small-diameter galactic planetary nebulae (PNe) representing the earliest phases of PN evolution. The IPHAS catalogue of H-emitting stars provides a useful basis for this study since all sources present in this catalogue must be of small angular diameter. Methods. The PN candidates are selected based on their location in two colour-colour diagrams: IPHAS (r' - H) vs. (r' - i'), and 2MASS (J - H) vs. (H - ). Spectroscopic follow-up was carried out on a sample of candidates to confirm their nature. Results. We present a total of 83 PN candidates. We were able to obtain spectra or find the classification from the literature for 35 candidates. Five of these objects are likely to be new PNe, including one large bipolar PN discovered serendipitously close to an emission-line star. PN distances deduced from extinction-distance relations based on IPHAS field-star photometry are presented for the first time. These yield distance estimates for our objects in the range 2 kpc and 6 kpc. From the data in hand, we conclude that four of the discovered objects are probably young PNe.Peer reviewe
The QUIJOTE experiment: project overview and first results
QUIJOTE (Q-U-I JOint TEnerife) is a new polarimeter aimed to characterize the
polarization of the Cosmic Microwave Background and other Galactic and
extragalactic signals at medium and large angular scales in the frequency range
10-40 GHz. The multi-frequency (10-20~GHz) instrument, mounted on the first
QUIJOTE telescope, saw first light on November 2012 from the Teide Observatory
(2400~m a.s.l). During 2014 the second telescope has been installed at this
observatory. A second instrument at 30~GHz will be ready for commissioning at
this telescope during summer 2015, and a third additional instrument at 40~GHz
is now being developed. These instruments will have nominal sensitivities to
detect the B-mode polarization due to the primordial gravitational-wave
component if the tensor-to-scalar ratio is larger than r=0.05.Comment: To appear in "Highlights of Spanish Astrophysics VIII", Proceedings
of the XI Scientific Meeting of the Spanish Astronomical Society, Teruel,
Spain (2014
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