1,441 research outputs found
Presencia de Aphis arbuti Ferrari y Wahlgreniella nervata (Gillete) (Hemiptera, Aphididae) en los madroños de la Comunidad de Madrid y estudio de la fumagina asociada.
Determinación de los pulgones asociados al madroño y su relación con los hongos desarrollados sobre la melaza
Discovery of two simultaneous non-harmonically related Quasi-Periodic Oscillations in the 2005 outburst of the black-hole binary GRO J1655-40
We studied the low-frequency quasi-periodic oscillations (LFQPOs) in the
black hole GRO J1655-40 during the 2005 outburst, using data from the Rossi
X-ray Timing Explorer. All LFQPOs could be identified as either type B or type
C using previously proposed classification schemes. In the soft state of the
outburst the type-C LFQPOs reached frequencies that are among the highest ever
seen for LFQPOs in black holes. At the peak of the outburst, in the
ultra-luminous state, the power spectrum showed two simultaneous,
non-harmonically related peaks which we identified as a type-B and a type-C
QPO. The simultaneous presence of a type-C and type-B QPO shows that at least
two of the three known LFQPO types are intrinsically different and likely the
result of distinct physical mechanisms. We also studied the properties of a
broad peaked noise component in the power spectra of the ultra-luminous state.
This noise component becomes more coherent with count rate and there are strong
suggestions that it evolves into a type-B QPO at the highest observed count
rates.Comment: 14 pages, 6 figures, 2 tables, accepted for publication in MNRA
Fast-ion redistribution and loss due to edge perturbations in the ASDEX Upgrade, DIII-D and KSTAR tokamaks
The impact of edge localized modes (ELMs) and externally applied resonant and non-resonant magnetic perturbations (MPs) on fast-ion confinement/transport have been investigated in the ASDEX Upgrade (AUG), DIII-D and KSTAR tokamaks. Two phases with respect to the ELM cycle can be clearly distinguished in ELM-induced fast-ion losses. Inter-ELM losses are characterized by a coherent modulation of the plasma density around the separatrix while intra-ELM losses appear as well-defined bursts. In high collisionality plasmas with mitigated ELMs, externally applied MPs have little effect on kinetic profiles, including fast-ions, while a strong impact on kinetic profiles is observed in low-collisionality, low q(95) plasmas with resonant and non-resonant MPs. In low-collisionality H-mode plasmas, the large fast-ion filaments observed during ELMs are replaced by a loss of fast-ions with a broad-band frequency and an amplitude of up to an order of magnitude higher than the neutral beam injection prompt loss signal without MPs. A clear synergy in the overall fast-ion transport is observed between MPs and neoclassical tearing modes. Measured fast-ion losses are typically on banana orbits that explore the entire pedestal/scrape-off layer. The fast-ion response to externally applied MPs presented here may be of general interest for the community to better understand the MP field penetration and overall plasma response.Ministerio de Economía y Competitividad RYC-2011-09152, ENE2012-31087Marie Curie FP7 Integration PCIG11-GA-2012-321455US Department of Energy DE-FC02-04ER54698, SC-G903402, DEFG02- 04ER54761, DE-AC02-09CH11466, DE-FG02- 08ER54984NRF Korea 2009-008201
Suppression of ferromagnetic ordering in doped manganites: Effects of the superexchange interaction
From a Monte Carlo study of the ferromagnetic Kondo lattice model for doped
manganites, including the antiferromagnetic superexchange interaction
(), we found that the ferromagnetic ordering was suppressed as
increased. The ferromagnetic transition temperature , as obtained from a
mean field fit to the calculated susceptibilities, was found to decrease
monotonically with increasing . Further, the suppression in
scales with the bandwidth narrowing induced by the antiferromagnetic
frustration originating from . From these results, we propose that the
change in the superexchange interaction strength between the electrons
of the Mn ions is one of the mechanisms responsible for the suppression in
observed in manganites of the type
(LaPr)CaMnO.Comment: 5 pages, 6 figures. To appear in PR
The Ubiquity of the rms-flux relation in Black Hole X-ray Binaries
We have investigated the short term linear relation between the rms
variability and the flux in 1,961 observations of 9 black hole X-ray binaries.
The rms-flux relation for the 1-10 Hz range is ubiquitously observed in any
observation with good variability signal to noise (> 3 % 1-10 Hz fractional
rms). This concurs with results from a previous study of Cygnus X-1 (Gleissner
et. al. 2004), and extends detection of the rms-flux relation to a wider range
of states. We find a strong dependence of the flux intercept of the rms-flux
relation on source state; as the source transitions from the hard state into
the hard intermediate state the intercept becomes strongly positive. We find
little evidence for flux dependence of the broad-band noise within the PSD
shape, excepting a small subset of observations from one object in an anomalous
soft-state. We speculate that the ubiquitous linear rms-flux relation in the
broad band noise of this sample, representing a range of different states and
objects, indicates that its formation mechanism is an essential property of the
luminous accretion flow around black holes.Comment: 12 pages, 6 figures, accepted for publication in MNRA
NiO diluted in high surface area TiO2 as efficient catalysts for the oxidative dehydrogenation of ethane
[EN] Catalysts consisting of NiO diluted in high surface area TiO2 can be as efficient in the oxidative dehydrogenation of ethane as the most selective NiO-promoted catalysts reported previously in the literature. By selecting the titania matrix and the NiO loading, yields to ethylene over 40% have been obtained. In the present article, three different titanium oxides (TiO2) have been employed as supports or diluters of nickel oxide and have been tested in the oxidative dehydrogenation of ethane to ethylene. All TiO2 used present anatase as the main crystalline phase and different surface areas of 11,55 and 85 m(2) g(-1). It has been observed that by selecting an appropriate nickel loading and the titanium oxide extremely high selectivity towards ethylene can be obtained. Thus, nickel oxide supported on TiO2 with high surface areas (i.e. 55 and 85 m(2) g(-1)) have resulted to give the best catalytic performance although the optimal nickel loading is different for each case. The optimal catalyst has been obtained for NiO-loadings up to 5-10 theoretical monolayers regardless of the TiO2 employed. Free TiO2 is inactive whereas unsupported NiO is active and unselective (forming mainly carbon dioxide) and, therefore, unmodified NiO particles have to be avoided in order to obtain the optimal catalytic performance. The use of low surface area titania (11 m(2) g(-1)) have led to the lowest selectivity to olefin due to the presence of an excess of free NiO particles. (C) 2017 Elsevier B.V. All rights reserved.The authors would like to acknowledge the DGICYT in Spain CTQ2012-37925-C03-2, CTQ2015-68951-C3-1-R, CTQ2015-68951-C3-3-R and SEV-2012-0267 Projects for financial support. D.D. also thanks Severo Ochoa Excellence fellowship (SVP-2014-068669). We also thank the University of Valencia (UV-INV-AE-16-484416 project) and SCSIE-UV for assistanceSanchis, R.; Delgado-Muñoz, D.; Agouram, S.; Soriano Rodríguez, MD.; Vázquez, MI.; Rodriguez-Castellon, E.; Solsona, B.... (2017). NiO diluted in high surface area TiO2 as efficient catalysts for the oxidative dehydrogenation of ethane. Applied Catalysis A General. 536:18-26. https://doi.org/10.1016/j.apcata.2017.02.012S182653
Fossil Groups Origins III. Characterization of the sample and observational properties of fossil systems
(Abridged) Fossil systems are group- or cluster-sized objects whose
luminosity is dominated by a very massive central galaxy. In the current cold
dark matter scenario, these objects formed hierarchically at an early epoch of
the Universe and then slowly evolved until present day. That is the reason why
they are called {\it fossils}. We started an extensive observational program to
characterize a sample of 34 fossil group candidates spanning a broad range of
physical properties. Deep band images were taken for each candidate and
optical spectroscopic observations were obtained for 1200 galaxies. This
new dataset was completed with SDSS DR7 archival data to obtain robust cluster
membership and global properties of each fossil group candidate. For each
system, we recomputed the magnitude gaps between the two brightest galaxies
() and the first and fourth ranked galaxies ()
within 0.5 . We consider fossil systems those with mag or mag within the errors. We find
that 15 candidates turned out to be fossil systems. Their observational
properties agree with those of non-fossil systems. Both follow the same
correlations, but fossils are always extreme cases. In particular, they host
the brightest central galaxies and the fraction of total galaxy light enclosed
in the central galaxy is larger in fossil than in non-fossil systems. Finally,
we confirm the existence of genuine fossil clusters. Combining our results with
others in the literature, we favor the merging scenario in which fossil systems
formed due to mergers of galaxies. The large magnitude gap is a
consequence of the extreme merger ratio within fossil systems and therefore it
is an evolutionary effect. Moreover, we suggest that at least one candidate in
our sample could represent a transitional fossil stage.Comment: 14 pages, 11 figures, accepted for publication in A&
Phytochemical Characterization and Antiplatelet Activity of Mexican Red Wines and Their By-products
Red wines and their grape pomaces are important sources of phenolic compounds. Inhibition of plateletaggregation is one of the mechanisms proposed for cardioprotective effect of phenolic compounds fromwine and grape pomace; however, phenolic content is affected by region, variety and winemaking process.In the present study, antiplatelet effect of red wines and grape pomaces was related to its phenolic content(determined by spectrophotometric techniques) and profile (determined using HPLC-MS/MS). in vitroAnti-platelet aggregation was determined using human platelets. Results showed that Zinfandel wine andCabernet Sauvignon grape pomace presented the highest phenolic content. Phenolic profiles presenteddifferences in the presence of flavonoids and oligomeric tannins. Results from platelet aggregationshowed that Merlot and Petit Verdot wines and Petit Verdot grape pomace sample presented the highestantiaggregant effect. These results indicate that antiplatelet effect could be related to phenolic profile thanphenolic content in wines and grape pomaces. Cardioprotective effect of red wines and grape pomacecould be related to specific compounds such as monomeric and polymeric flavan-3-ols
Overview of the JET preparation for deuterium–tritium operation with the ITER like-wall
For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des.
82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T,
leading up to 2020 and the first experiments with 50%/50% D–T mixtures since 1997 and the
first ever D–T plasmas with the ITER mix of plasma-facing component materials. For this
purpose, a concerted physics and technology programme was launched with a view to prepare
the D–T campaign (DTE2). This paper addresses the key elements developed by the JET
programme directly contributing to the D–T preparation. This intense preparation includes
the review of the physics basis for the D–T operational scenarios, including the fusion power
predictions through first principle and integrated modelling, and the impact of isotopes in the
operation and physics of D–T plasmas (thermal and particle transport, high confinement mode
(H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving
several aspects of plasma operation for DTE2, such as real time control schemes, heat load
control, disruption avoidance and a mitigation system (including the installation of a new
shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the threeions scheme), new diagnostics (neutron camera and spectrometer, active Alfvèn eigenmode
antennas, neutral gauges, radiation hard imaging systems…) and the calibration of the JET
neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation
of JET for the 2020 D–T campaign provides an incomparable source of information and a
basis for the future D–T operation of ITER, and it is also foreseen that a large number of key
physics issues will be addressed in support of burning plasmas.EURATOM 63305
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