162 research outputs found
Deducing high pressure behavior for chemically fragile systems: the polymorphism of spironolactone
International audienc
Polymorphism of spironolactone: An unprecedented case of monotropy turning to enantiotropy with a huge difference in the melting temperatures
Postprint (author's final draft
Taphonomic Criteria for Identifying Iberian Lynx Dens in Quaternary Deposits
For decades, taphonomists have dedicated their efforts to assessing the nature of the massive leporid accumulations recovered at archaeological sites in the northwestern Mediterranean region. Their interest lying in the fact that the European rabbit constituted a critical part of human subsistence during the late Pleistocene and early Holocene. However, rabbits are also a key prey in the food webs of Mediterranean ecosystems and the base of the diet for several specialist predators, including the Iberian lynx (Lynx pardinus). For this reason, the origin of rabbit accumulations in northwestern Mediterranean sites has proved a veritable conundrum. Here, we present the zooarchaeological and taphonomic study of more than 3000 faunal and 140 coprolite remains recovered in layer IIIa of Cova del Gegant (Catalonia, Spain). Our analysis indicates that this layer served primarily as a den for the Iberian lynx. The lynxes modified and accumulated rabbit remains and also died at the site creating an accumulation dominated by the two taxa. However, other agents and processes, including human, intervened in the final configuration of the assemblage. Our study contributes to characterizing the Iberian lynx fossil accumulation differentiating between the faunal assemblages accumulated by lynxes and hominins
Thermodynamic Structure of the Solar Corona: Tomographic Reconstructions and MHD Modeling
We carry out a study of the global three-dimensional (3D) structure of the
electron density and temperature of the quiescent inner solar corona () by means of tomographic reconstructions and magnetohydrodynamic
simulations. We use differential emission measure tomography (DEMT) and the
Alfv\'en Wave Solar Model (AWSoM), in their latest versions. Two target
rotations were selected from the solar minimum between solar cycles (SCs) 23
and 24 and the declining phase of SC 24. We report in quantitative detail on
the 3D thermodynamic structure of the core and outer layers of the streamer
belt, and of the high latitude coronal holes (CH), as revealed by the DEMT
analysis. We report on the presence of two types of structures within the
streamer belt, loops with temperature decreasing/increasing with height (dubbed
down/up loops), as reported first in previous DEMT studies. We also estimate
the heating energy flux required at the coronal base to keep these structures
stable, found to be or order , consistently with
previous DEMT and spectroscopic studies. We discuss how these findings are
consistent with coronal dissipation of Alfv\'en waves. We compare the 3D
results of DEMT and AWSoM in distinct magnetic structures. We show that the
agreement between the products of both techniques is the best so far, with an
overall agreement , depending on the target rotation and the
specific coronal region. In its current implementation the ASWsoM model can not
reproduce down loops though. Also, in the source region of the fast and slow
components of the solar wind, the electron density of the AWSoM model increases
with latitude, opposite to the trend observed in DEMT reconstructions
SP-0489: HPV-transformation in the cervix and at non-cervical sites
Pla general d'un dels panells horitzontals sobre espais verds de Barcelona a l'exposició Ciutat. Barcelona projecta a l'Edifici Fòrum. Exposició sobre la planificació urbanística i arquitectònica de Barcelon
Barocaloric properties of quaternary Mn3(Zn,In)N for room-temperature refrigeration applications
The magnetically frustrated manganese nitride antiperovskite family displays significant changes of entropy under hydrostatic pressure that can be useful for the emerging field of barocaloric cooling. Here we show that barocaloric properties of metallic antiperovskite Mn nitrides can be tailored for room-temperature application through quaternary alloying. We find an enhanced entropy change of |¿St|=37JK-1kg-1 at the Tt=300K antiferromagnetic transition of quaternary Mn3Zn0.5In0.5N relative to the ternary end members. The pressure-driven barocaloric entropy change of Mn3Zn0.5In0.5N reaches |¿SBCE|=20JK-1kg-1 in 2.9 kbar. Our results open up a large phase space where compounds with improved barocaloric properties may be found.Peer ReviewedPostprint (author's final draft
Injection of iodine to the stratosphere
© 2015. American Geophysical Union. All Rights Reserved. We report a new estimation of the injection of iodine into the stratosphere based on novel daytime (solar zenith angle < 45°) aircraft observations in the tropical tropopause layer and a global atmospheric model with the most recent knowledge about iodine photochemistry. The results indicate that significant levels of total reactive iodine (0.25-0.7 parts per trillion by volume), between 2 and 5 times larger than the accepted upper limits, can be injected into the stratosphere via tropical convective outflow. At these iodine levels, modeled iodine catalytic cycles account for up to 30% of the contemporary ozone loss in the tropical lower stratosphere and can exert a stratospheric ozone depletion potential equivalent to, or even larger than, that of very short-lived bromocarbons. Therefore, we suggest that iodine sources and chemistry need to be considered in assessments of the historical and future evolution of the stratospheric ozone layer.Peer Reviewe
Simulating Solar Maximum Conditions Using the Alfvén Wave Solar Atmosphere Model (AWSoM)
To simulate solar coronal mass ejections (CMEs) and predict their time of arrival and geomagnetic impact, it is important to accurately model the background solar wind conditions in which CMEs propagate. We use the Alfvén Wave Solar atmosphere Model (AWSoM) within the the Space Weather Modeling Framework to simulate solar maximum conditions during two Carrington rotations and produce solar wind background conditions comparable to the observations. We describe the inner boundary conditions for AWSoM using the ADAPT global magnetic maps and validate the simulated results with EUV observations in the low corona and measured plasma parameters at L1 as well as at the position of the Solar Terrestrial Relations Observatory spacecraft. This work complements our prior AWSoM validation study for solar minimum conditions and shows that during periods of higher magnetic activity, AWSoM can reproduce the solar plasma conditions (using properly adjusted photospheric Poynting flux) suitable for providing proper initial conditions for launching CMEs.Fil: Sachdeva, Nishtha. University of Michigan; Estados UnidosFil: Tóth, Gábor. University of Michigan; Estados UnidosFil: Manchester, Ward B.. University of Michigan; Estados UnidosFil: van der Holst, Bart. University of Michigan; Estados UnidosFil: Huang, Zhenguang. University of Michigan; Estados UnidosFil: Sokolov, Igor V.. University of Michigan; Estados UnidosFil: Zhao, Lulu. University of Michigan; Estados UnidosFil: Al Shidi, Qusai. University of Michigan; Estados UnidosFil: Chen, Yuxi. University of Michigan; Estados UnidosFil: Gombosi, Tamas I.. University of Michigan; Estados UnidosFil: Henney, Carl J.. University of Michigan; Estados UnidosFil: Lloveras, Diego Gustavo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Vasquez, Alberto Marcos. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin
- …