1,578 research outputs found
Mesozoic geology of Cape Shirreff, Livingston Island, South Shetland Islands, Antarctica
The stratigraphic succession at Cape Shirr e ff has a minimum thickness of 450 m and is mainly composed of lavas and a smaller amount of volcaniclastic breccias. Lavas are subalkaline olivine basalts and basaltic andesites which are locally well - bedded, but in most areas give a homogeneous, sometimes massive aspect to outcrops. Volcaniclastic massive breccias are found in the northern part of Cape Shirreff where they are interstratified with lavas in a few outcrops. Breccias are indurated, heterometric, grain - supported and consist of angular to subangular volcanic rock fragments, 5 to 80 cm in diameter. Petrographic evidence of magma supercooling (skeletal microlites of plagioclase, thermal - shocked phenocrysts of olivine) enables a subaqueous environment for part of the lavas to be deposited and suggests a possible hyaloclastic origin for some interstratified volcanic breccias. The whole succession is cut by subve rtical dykes (10 to 40 cm thick and a few meters to 400 m long), which show variable trends around a NW-SE maximum. These consist of commonly vesiculated basaltic and basaltic andesite porp hyritic rocks, commonly indistinguishable from the lava bodies. Lavas dip variably between 15 and 80º, more gently in the south than in the central and northern areas. Although significant variations in dipping attitude could be associated with depositional geometries, the general dipping pattern is clearly consistent with NW-SE oriented large-scale folds showing a gentle dome and basin structure. In the southern area, the NW-SE folds are not so well developed and the structure seems to be consistent with an interference of N-S and E-W oriented folds. The large scale NW-SE folds are consistent with NE-SW shortening. This shortening direction is parallel to the direction of extension deducible from dykes and, hence, folds and dykes are not consistent with the same deformational event
Nuevos retos moleculares en la conservación animal
The contribution of genetics to wildlife conservation has been stressed often forgetting the existing theoretical and empirical limitations in the use of genetic information to solve ecological and demographic problems. The possibilities of molecular analyses are extensive and the automation of procedures is increasing the efficiency and reducing the cost of molecular technology. With large amounts of molecular data already available, the interest is switching towards the analysis of these data and the interpretation of genetic variability within and across species from a functional perspective. The understanding of the link between genetic variation and fitness or survival is essential in conservation biology and this understanding needs the combination of molecular data with non–molecular (e.g. physiological, behavioural and ecological) data. Progress in this promising field will depend on the trust and collaboration between molecular and field biologists.La contribución de la genética a la conservación de la vida salvaje ha sido enfatizada, olvidándose a menudo que existen limitaciones teóricas y empíricas sobre el uso de la información genética para solucionar problemas ecológicos y demográficos. Los análisis moleculares ofrecen numerosas posibilidades y la automatización de los procesos está incrementando la eficiencia y reduciendo los costes de la tecnología molecular. Con grandes cantidades de datos moleculares ya disponibles, el interés se está desplazando hacia el análisis de dichos datos y la interpretación de la variabilidad genética intraespecífica e interespecífica desde una perspectiva funcional. La comprensión del vínculo entre variabilidad genética y eficacia biológica o supervivencia es esencial en la biología de la conservación, requiriendo esta comprensión la combinación de datos moleculares con datos no moleculares (por ejemplo fisiológicos, de comportamiento y ecológicos). El progreso en este campo tan prometedor debe basarse en la confianza y la colaboración entre biólogos moleculares y de campo
StarHorse: A Bayesian tool for determining stellar masses, ages, distances, and extinctions for field stars
Understanding the formation and evolution of our Galaxy requires accurate
distances, ages and chemistry for large populations of field stars. Here we
present several updates to our spectro-photometric distance code, that can now
also be used to estimate ages, masses, and extinctions for individual stars.
Given a set of measured spectro-photometric parameters, we calculate the
posterior probability distribution over a given grid of stellar evolutionary
models, using flexible Galactic stellar-population priors. The code (called
{\tt StarHorse}) can acommodate different observational datasets, prior
options, partially missing data, and the inclusion of parallax information into
the estimated probabilities. We validate the code using a variety of simulated
stars as well as real stars with parameters determined from asteroseismology,
eclipsing binaries, and isochrone fits to star clusters. Our main goal in this
validation process is to test the applicability of the code to field stars with
known {\it Gaia}-like parallaxes. The typical internal precision (obtained from
realistic simulations of an APOGEE+Gaia-like sample) are in
distance, in age, in mass, and mag in
. The median external precision (derived from comparisons with earlier
work for real stars) varies with the sample used, but lies in the range of
for distances, for ages,
for masses, and mag for . We provide StarHorse distances and
extinctions for the APOGEE DR14, RAVE DR5, GES DR3 and GALAH DR1 catalogues.Comment: 21 pages, 12 figures, accepte
Observations of SN2011fe with INTEGRAL
SN2011fe was detected by the Palomar Transient Factory on August 24th 2011 in
M101 few hours after the explosion. From the early spectra it was immediately
realized that it was a Type Ia supernova thus making this event the brightest
one discovered in the last twenty years. In this paper the observations
performed with the instruments on board of INTEGRAL (SPI, IBIS/ISGRI, JEM-X and
OMC) before and after the maximum of the optical light as well as the
interpretation in terms of the existing models of --ray emission from
such kind of supernovae are reported. All INTEGRAL high-energy have only been
able to provide upper limits to the expected emission due to the decay of
Ni. These bounds allow to reject explosions involving a massive white
dwarf in the sub--Chandrasekhar scenario. On the other hand, the optical light
curve obtained with the OMC camera suggests that the event was produced by a
delayed detonation of a CO white dwarf that produced M of
Ni. In this particular case, INTEGRAL would have only been able to
detect the early --ray emission if the supernova had occurred at a
distance of 2 -3 Mpc, although the brightest event could be visible up to
distances larger by a factor two.Comment: Proceedings of "An INTEGRAL view of the high-energy sky (the first 10
years)" the 9th INTEGRAL Workshop, October 15-19, 2012, Paris, France, in
Proceedings of Science (INTEGRAL 2012), Eds. A. Goldwurm, F. Lebrun and C.
Winkler, http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=176, id number
PoS (INTEGRAL 2012) 103 (2013
Multi-stakeholder development of a serious game to explore the water-energy-food-land-climate nexus: The SIM4NEXUS approach
This is the final version of the article. Available from the publisher via the DOI in this record.Water, energy, food, land and climate form a tightly-connected nexus in which actions on one sector impact other sectors, creating feedbacks and unanticipated consequences. This is especially because at present, much scientific research and many policies are constrained to single discipline/sector silos that are often not interacting (e.g., water-related research/policy). However, experimenting with the interaction and determining how a change in one sector could impact another may require unreasonable time frames, be very difficult in practice and may be potentially dangerous, triggering any one of a number of unanticipated side-effects. Current modelling often neglects knowledge from practice. Therefore, a safe environment is required to test the potential cross-sectoral implications of policy decisions in one sector on other sectors. Serious games offer such an environment by creating realistic 'simulations', where long-term impacts of policies may be tested and rated. This paper describes how the ongoing (2016-2020) Horizon2020 project SIM4NEXUS will develop serious games investigating potential plausible cross-nexus implications and synergies due to policy interventions for 12 multi-scale case studies ranging from regional to global. What sets these games apart is that stakeholders and partners are involved in all aspects of the modelling definition and process, from case study conceptualisation, quantitative model development including the implementation and validation of each serious game. Learning from playing a serious game is justified by adopting a proof-of-concept for a specific regional case study in Sardinia (Italy). The value of multi-stakeholder involvement is demonstrated, and critical lessons learned for serious game development in general are presented.The work described in this paper has been conducted within the project SIM4NEXUS.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme
under Grant Agreement No. 689150 SIM4NEXUS
Observation of SN2011fe with INTEGRAL. I. Pre--maximum phase
SN2011fe was detected by the Palomar Transient Factory on August 24th 2011 in
M101 a few hours after the explosion. From the early optical spectra it was
immediately realized that it was a Type Ia supernova thus making this event the
brightest one discovered in the last twenty years. The distance of the event
offered the rare opportunity to perform a detailed observation with the
instruments on board of INTEGRAL to detect the gamma-ray emission expected from
the decay chains of Ni. The observations were performed in two runs, one
before and around the optical maximum, aimed to detect the early emission from
the decay of Ni and another after this maximum aimed to detect the
emission of Co. The observations performed with the instruments on board
of INTEGRAL (SPI, IBIS/ISGRI, JEMX and OMC) have been analyzed and compared
with the existing models of gamma-ray emission from such kind of supernovae. In
this paper, the analysis of the gamma-ray emission has been restricted to the
first epoch. Both, SPI and IBIS/ISGRI, only provide upper-limits to the
expected emission due to the decay of Ni. These upper-limits on the
gamma-ray flux are of 7.1 10 ph/s/cm for the 158 keV line
and of 2.3 10 ph/s/cm for the 812 keV line. These bounds
allow to reject at the level explosions involving a massive white
dwarf, M in the sub--Chandrasekhar scenario and specifically
all models that would have substantial amounts of radioactive Ni in the
outer layers of the exploding star responsible of the SN2011fe event. The
optical light curve obtained with the OMC camera also suggests that SN2011fe
was the outcome of the explosion, possibly a delayed detonation although other
models are possible, of a CO white dwarf that synthesized M
of Ni. For this specific model.Comment: Accepted for publication in A&A. 10 pages, 10 figure
Heliospheric Transport of Neutron-Decay Protons
We report on new simulations of the transport of energetic protons
originating from the decay of energetic neutrons produced in solar flares.
Because the neutrons are fast-moving but insensitive to the solar wind magnetic
field, the decay protons are produced over a wide region of space, and they
should be detectable by current instruments over a broad range of longitudes
for many hours after a sufficiently large gamma-ray flare. Spacecraft closer to
the Sun are expected to see orders-of magnitude higher intensities than those
at the Earth-Sun distance. The current solar cycle should present an excellent
opportunity to observe neutron-decay protons with multiple spacecraft over
different heliographic longitudes and distances from the Sun.Comment: 12 pages, 4 figures, to be published in special issue of Solar
Physic
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