152 research outputs found
Reunion overseas: introduced wild boars and cultivated orange trees interact in the Brazilian Atlantic forest
Little is known concerning novel interactions between species that typically
interact in their native range but, as a consequence of human activity, are also interacting out of their original
distribution under new ecological conditions. Objective: We investigate the interaction between the orange tree
and wild boar, both of which share Asian origins and have been introduced to the Americas (i.e. the overseas).
Methods: Specifically, we assessed whether i) wild boars consume orange (Citrus sinensis) fruits and seeds
in orchards adjacent to a remnant of the Atlantic Forest of Brazil, ii) the orange seeds are viable after passing
through boar’s digestive tract and iii) whether the orange tree may naturalise in the forest remnant assisted by
wild boars. Results: Our camera surveys indicated that wild boar was by far the most frequent consumer of
orange fruits (40.5 % of camera trap-days). A considerable proportion of sown orange seeds extracted from fresh
boar feces emerged seedlings (27.8 %, N = 386) under controlled greenhouse conditions. Further, 37.6 % of sown
seeds (N = 500) in the forest remnant emerged seedlings in July 2015; however, after ~4 years (March 2019)
only 9 seedlings survived (i.e. 4.8 %, N = 188). Finally, 52 sweet orange seedlings were found during surveys
within the forest remnant which is intensively used by wild boars. This study indicates a high potential of boars
to act as effective seed dispersers of the sweet orange. However, harsh competition with native vegetation and
the incidence of lethal diseases, which quickly kill sweet orange trees under non-agricultural conditions, could
seriously limit orange tree establishment in the forest. Conclusions: Our results have important implications not
only because the wild boar could be a vector of potential invasive species, but also because they disperse seeds
of some native species (e.g. the queen palm, Syagrus romanzofiana) in defaunated forests, where large native
seed dispersers are missing; thus, wild boars could exert critical ecological functions lost due to human activityinfo:eu-repo/semantics/publishedVersio
Exploring the dimming event of RW Aur A through multi-epoch VLT/X-Shooter spectroscopy
RW Aur A is a CTTS that has suddenly undergone three major dimming events
since 2010. We aim to understand the dimming properties, examine accretion
variability, and derive the physical properties of the inner disc traced by the
CO ro-vibrational emission at NIR wavelengths (2.3 mic).
We compared two epochs of X-Shooter observations, during and after the
dimming. We modelled the rarely detected CO bandhead emission in both epochs to
examine whether the inner disc properties had changed. The SED was used to
derive the extinction properties of the dimmed spectrum and compare the
infrared excess between the two epochs. Lines tracing accretion were used to
derive the mass accretion rate in both states. The CO originates from a region
with physical properties of T=3000 K, N=1x10 cm and
vsini=113 km/s. The extinction properties of the dimming layer were derived
with the effective optical depth ranging from teff 2.5-1.5 from the UV to the
NIR. The inferred mass accretion rate Macc is Msun/yr and Msun/yr after and during the dimming respectively. By fitting the
SED, additional emission is observed in the IR during the dimming event from
dust grains with temperatures of 500-700K. The physical conditions traced by
the CO are similar for both epochs, indicating that the inner gaseous disc
properties do not change during the dimming events. The extinction curve is
flatter than that of the ISM, and large grains of a few hundred microns are
thus required. When we correct for the observed extinction, Macc is constant in
the two epochs, suggesting that the accretion is stable and therefore does not
cause the dimming. The additional hot emission in the NIR is located at about
0.5 au from the star. The dimming events could be due to a dust-laden wind, a
severe puffing-up of the inner rim, or a perturbation caused by the recent
star-disc encounter.Comment: Accepted by Astronomy & Astrophysic
Fractionation and fluxes of metals and radionuclides during the recycling process of phosphogypsum wastes applied to mineral CO2 sequestration
The industry of phosphoric acid produces a calcium-rich by-product known as phosphogypsum, which is usually stored in large stacks of millions of tons. Up to now, no commercial application has been widely implemented for its reuse because of the significant presence of potentially toxic contaminants. This work confirmed that up to 96% of the calcium of phosphogypsum could be recycled for CO2 mineral sequestration by a simple two-step process: alkaline dissolution and aqueous carbonation, under ambient pressure and temperature. This CO2 sequestration process based on recycling phosphogypsum wastes would help to mitigate greenhouse gasses emissions. Yet this work goes beyond the validation of the sequestration procedure; it tracks the contaminants, such as trace metals or radionuclides, during the recycling process in the phosphogypsum. Thus, most of the contaminants were transferred from raw phosphogypsum to portlandite, obtained by dissolution of the phosphogypsum in soda, and from portlandite to calcite during aqueous carbonation. These findings provide valuable information for managing phosphogypsum wastes and designing potential technological applications of the by-products of this environmentally-friendly proposal.Junta de Andalucía P10-RNM-6300, P12- RNM-226
Interspecific interactions among functionally diverse frugivores and their outcomes for plant reproduction: a new approach based on camera-trap data and tailored null models
Research ArticleThe study of plant-frugivore interactions is essential to understand the ecology and evolution
of many plant communities. However, very little is known about how interactions among frugivores
indirectly affect plant reproductive success. In this study, we examined direct interactions
among vertebrate frugivores sharing the same fruit resources. Then, we inferred
how the revealed direct interspecific interactions could lead to indirect (positive or negative)
effects on reproductive success of fleshy fruited plants. To do so, we developed a new analytical
approach that combines camera trap data (spatial location, visitor species, date and
time, activity) and tailored null models that allowed us to infer spatial-temporal interactions
(attraction, avoidance or indifference) between pairs of frugivore species. To illustrate our
approach, we chose to study the system composed by the Mediterranean dwarf palm, Chamaerops
humilis, the Iberian pear tree, Pyrus bourgaeana, and their shared functionally
diverse assemblages of vertebrate frugivores in a Mediterranean area of SW Spain. We first
assessed the extent to which different pairs of frugivore species tend to visit the same or different
fruiting individual plants. Then, for pairs of species that used the same individual
plants, we evaluated their spatial-temporal relationship. Our first step showed, for instance,
that some prey frugivore species (e.g. lagomorphs) tend to avoid those C. humilis individuals
that were most visited by their predators (e.g. red foxes). Also, the second step revealed
temporal attraction between large wild and domestic frugivore ungulates (e.g. red deer,
cows) and medium-sized frugivores (e.g. red foxes) suggesting that large mammals could
facilitate the C. humilis and P. bourgaeana exploitation to other smaller frugivores by making
fruits more easily accessible. Finally, our results allowed us to identify direct interaction pathways,
that revealed how the mutualistic and antagonistic relations between animal associates
derived into indirect effects on both plants seed dispersal success. For instance, we
found that large-sized seed predators (e.g. ungulates) had a direct positive effect on the likelihood
of visits by legitimate seed dispersers (e.g. red foxes) to both fleshy fruited plants.
Then, seed predators showed an indirect positive effect on the plants’ reproductive Our new analytical approach provides a widely applicable framework for further studies on
multispecies interactions in different systems beyond plant-frugivore interactions, including
plant-pollinator interactions, the exploitation of plants by herbivores, and the use of carcasses
by vertebrate scavengersinfo:eu-repo/semantics/publishedVersio
Bioactivity of wollastonite/aerogels composites obtained from a TEOS-MTES matrix
Organic-inorganic hybrid materials were synthesized by controlled hydrolysis of tetraethoxysilane (TEOS), methyltrimethoxysilane (MTES), synthetic wollastonite powders and polydimethylsiloxane (PDMS) in an ethanol solution. Aerogels were prepared from acid hydrolysis of TEOS and MTES with different volume ratio in ethanol, followed by addition of wollastonite powder and PDMS in order to obtain aerogels with 20 wt% of PDMS and 5 wt% of CaO of the total silica. Finally, when the wet gels were obtained, they were supercritically dried at 260°C and 90 bar, in ethanol. In order to obtain its bioactivity, one method for surface activation is based on a wet chemical alkaline treatment. The particular interest of this study is that we introduce hybrid aerogels, in a 1 M solution of NaOH, for 30 s at room temperature. We evaluate the bioactivity of TEOS-MTES aerogel when immersed in a static volume of simulated body fluid (SBF). An apatite layer of spherical-shaped particles of uniform size smaller than 5 microns is observed to form on the surface of the aerogels after 25 days soaking in SBF.Ministerio de Ciencia e Innovación MAT2005-01583Junta de Andalucía TEP 79
Fungal infestation boosts fruit aroma and fruit removal by mammals and birds
For four decades, an influential hypothesis has posited that competition for food resources between
microbes and vertebrates selects for microbes to alter these resources in ways that make them
unpalatable to vertebrates. We chose an understudied cross kingdom interaction to experimentally
evaluate the effect of fruit infection by fungi on both vertebrate (mammals and birds) fruit preferences
and on ecologically relevant fruit traits (volatile compounds, toughness, etc). Our well-replicated field
experiments revealed that, in contrast to previous studies, frugivorous mammals and birds consistently
preferred infested over intact fruits. This was concordant with the higher level of attractive volatiles
(esters, ethanol) in infested fruits. This investigation suggests that vertebrate frugivores, fleshyfruited
plants, and microbes form a tripartite interaction in which each part could interact positively
with the other two (e.g. both orange seeds and fungal spores are likely dispersed by mammals). Such
a mutualistic view of these complex interactions is opposed to the generalized idea of competition
between frugivorous vertebrates and microorganisms. Thus, this research provides a new perspective
on the widely accepted plant evolutionary dilemma to make fruits attractive to mutualistic frugivores
while unattractive to presumed antagonistic microbes that constrain seed dispersalinfo:eu-repo/semantics/publishedVersio
Parsec-scale jets driven by high-mass young stellar objects. Connecting the au- and the parsec-scale jet in IRAS 13481-6124
This is the author accepted manuscript. The final version is available from EDP Sciences via the DOI in this recordR.F. acknowledges support from Science Foundation
Ireland (grant 13/ERC/12907). A.C.G. and T.P.R. have received funding
from the European Research Council (ERC) under the European Union’s Horizon
2020 research and innovation programme (grant agreement No. 743029).
R.G.L has received funding from the European Union’s Horizon 2020 research
and innovation programme under the Marie Skłodowska-Curie Grant (agreement
No. 706320). S.K. acknowledges support from an STFC Rutherford Fellowship
(ST/J004030/1) and ERC Starting Grant (Grant Agreement No. 639889)
Radio outburst from a massive (proto)star. II. A portrait in space and time of the expanding radio jet from S255 NIRS3
Observations indicate that the accretion process in star formation may occur
through accretion outbursts. This phenomenon has also now been detected in a
few young massive (proto)stars (>8 Msun). The recent outburst at radio
wavelengths of the massive (proto)star S255 NIRS3 has been interpreted by us as
expansion of a thermal jet, fed by the infalling material. To follow up on our
previous study and confirm our interpretation, we monitored the source for more
than 1 yr in six bands from 1.5 GHz to 45.5 GHz and, after ~1.5 yr, with the
Atacama Large Millimeter/submillimeter Array at two epochs, which made it
possible to detect the proper motions of the jet lobes. The prediction of our
previous study is confirmed by the new results. The radio jet is found to
expand, while the flux, after an initial exponential increase, appears to
stabilise and eventually decline. The radio flux measured during our monitoring
is attributed to a single NE lobe, However, from 2019 a second lobe has been
emerging to the SW, probably powered by the same accretion outburst, although
with a delay of at least a couple of years. Flux densities at >6 GHz were
satisfactorily fitted with a jet model, whereas those below 6 GHz are clearly
underestimated by the model. This indicates that non-thermal emission becomes
dominant at long wavelengths. Our results suggest that thermal jets can be a
direct consequence of accretion events, when yearly flux variations are
detected. The end of the accretion outburst is mirrored in the radio jet, as ~1
yr after the onset of the radio outburst, the inner radius of the jet began to
increase while the jet mass stopped growing, as expected if the powering
mechanism of the jet is quenched. Our findings support a tight connection
between accretion and ejection in massive stars, consistent with a formation
process involving a disk-jet system similar to that of low-mass stars
Mirror, mirror on the outflow cavity wall: Near-infrared CO overtone disc emission of the high-mass YSO IRAS 11101-5829
Aims. The inner regions of high-mass protostars are often invisible in the near-infrared, obscured by thick envelopes and discs. We aim to investigate the inner gaseous disc of IRAS 11101-5829 through scattered light from the outflow cavity walls.
Methods. We observed the immediate environment of the high-mass young stellar object IRAS 11101-5829 and the closest knots of its jet, HH135-136, with the integral field unit VLT/SINFONI. We also retrieved archival data from the high-resolution long-slit spectrograph VLT/X-shooter. We analysed imaging and spectroscopic observations to discern the nature of the near-infrared CO emission.
Results. We detect the first three bandheads of the υ = 2−0 CO vibrational emission for the first time in this object. It is coincident with continuum and Brγ emission and extends up to ~10 000 au to the north-east and ~10 000 au to the south-west. The line profiles have been modelled as a Keplerian rotating disc assuming a single ring in local thermodynamic equilibrium. The model output gives a temperature of ~3000 K, a CO column density of ~1 × 1022 cm−2, and a projected Keplerian velocity vK sin idisc ~ 25 km s−1, which is consistent with previous modelling in other high-mass protostars. In particular, the low value of vK sin idisc suggests that the disc is observed almost face-on, whereas the well-constrained geometry of the jet imposes that the disc must be close to edge-on. This apparent discrepancy is interpreted as the CO seen reflected in the mirror of the outflow cavity wall.
Conclusions. From both jet geometry and disc modelling, we conclude that all the CO emission is seen through reflection by the cavity walls and not directly. This result implies that in the case of highly embedded objects, as for many high-mass protostars, line profile modelling alone might be deceptive and the observed emission could affect the derived physical and geometrical properties; in particular the inclination of the system can be incorrectly interpreted
New method for carbon dioxide mineralization based on phosphogypsum and aluminium-rich industrial wastes resulting in valuable carbonated by-products
A new carbon mineralization method was designed based on a sequestration agent synthesised exclusively from industrial wastes. Phosphogypsum waste from the fertiliser industry was dissolved into caustic aqueous waste from the aluminium anodising industry. The resulting precipitate consisted of katoite (Ca3Al2(OH)12, a Si-free hydrogrossular solid solution end-member of the Al-containing hydrogarnet) and thenardite (Na2SO4); the latter easily removed by rinsing with water. The carbonation performance of this katoite-rich sequestration agent was evaluated using two different methods, by bubbling in aqueous media and by weathering. Both procedures yielded high carbonation efficiencies (80% and 100%, respectively), and resulted in a solid precipitate composed primarily of calcite (CaCO3) and aluminium hydroxide (Al(OH)3). Priority attention was given to the transfer of trace elements and radionuclides of the uranium series typically present in the phosphogypsum. Results confirmed that the traces were transferred to resulting final solid carbonate at concentrations similar to those present in the raw phosphogypsum. In conclusion, these carbonated minerals would trap substantial amounts of CO2 and produce final materials with similar civil engineering uses to those proposed for current phosphogypsum wastes. This work offers new methods for jointly managing specific industrial wastes oriented to more sustainable industrial processes and controlling CO2 emissionsGobierno de España MAT2013-42934- RJunta de Andalucía P12-RNM-226
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