5,772 research outputs found
Revealing the dynamics of Class 0 protostellar discs with ALMA
We present synthetic ALMA observations of Keplerian, protostellar discs in
the Class 0 stage studying the emission of molecular tracers like CO,
CO, HCO, HCO, NH, and HCO. We model the
emission of discs around low- and intermediate-mass protostars. We show that
under optimal observing conditions ALMA is able to detect the discs already in
the earliest stage of protostellar evolution, although the emission is often
concentrated to the innermost 50 AU. Therefore, a resolution of a few 0.1"
might be too low to detect Keplerian discs around Class 0 objects. We also
demonstrate that under optimal conditions for edge-on discs Keplerian rotation
signatures are recognisable, from which protostellar masses can be inferred.
For this we here introduce a new approach, which allows us to determine
protostellar masses with higher fidelity than before. Furthermore, we show that
it is possible to reveal Keplerian rotation even for strongly inclined discs
and that ALMA should be able to detect possible signs of fragmentation in
face-on discs. In order to give some guidance for future ALMA observations, we
investigate the influence of varying observing conditions and source distances.
We show that it is possible to probe Keplerian rotation in inclined discs with
an observing time of 2 h and a resolution of 0.1", even in the case of moderate
weather conditions. Furthermore, we demonstrate that under optimal conditions,
Keplerian discs around intermediate-mass protostars should be detectable up to
kpc-distances.Comment: 17 pages, 17 figures, accepted for publication by MNRA
Neurogene Stammzelltransplantation in die Kochlea
Zusammenfassung: Hintergrund: Die Stammzelltherapie ist insbesondere im Hinblick auf eine Applikation im Innenohr interessant, da die Haarzellen nicht regenerieren. Einmal abgestorbene Haarzellen werden nicht ersetzt, es kommt zu einem irreversiblen Hörverlust. In den vergangenen Jahren konnten Stammzellen mit wechselndem Erfolg ins Innenohr appliziert werden, zum Teil haben sie sich zu Innenohrzellen entwickelt. In der vorliegenden Studie wollten wir untersuchen, wie sich neuronale Vorläuferzellen verhalten, wenn sie in vitro und in vivo auf ein geschädigtes Innenohr aufgebracht werden. Methoden: Neuronale Vorläuferzellen wurden von E9,5Tage alten Mausembryonen isoliert und danach mit einem Virus, der das grün fluoreszierende Protein (GFP) exprimiert, infiziert. In der Folge wurden die GFP+-neuralen Vorläuferzellen sowohl auf ein geschädigtes Corti-Organ in vitro aufgebracht als auch Mäusen ins zuvor geschädigte Innenohr in vivo appliziert. Anschließend wurden die Vorläuferzellen bzw. ihr Bezug zum Corti-Organ analysiert. Ergebnisse: Sowohl auf ein geschädigtes Corti-Organ aufgebrachte GFP+-neurale Vorläuferzellen als auch in vivo in geschädigte Innenohren transplantierte GFP+-neurale Vorläuferzellen konnten nach Transplantation nachgewiesen werden. Interessanterweise haben sich die GFP+-neuralen Vorläuferzellen nicht zufällig auf dem Organ niedergelassen, sondern ein gewisses Muster gezeigt. Insbesondere konnte nach der In-vivo-Applikation gesehen werden, dass die GFP+-neuralen Vorläuferzellen sich im Bereich des Corti-Organs in der Region von abgestorbenen Haarzellen angesiedelt haben. Schlussfolgerung: Neuronale Vorläuferzellen haben ein großes Potenzial, einmal abgestorbene Haarzellen zu ersetzen. Allerdings braucht es noch intensive Forschung bis zur klinischen Anwendun
SilvAdapt.Net: A Site-Based Network of Adaptive Forest Management Related to Climate Change in Spain
Adaptive forest management (AFM) is an urgent need because of the uncertainty regarding how changes in the climate will affect the structure, composition and function of forests during the next decades. Current research initiatives for the long-term monitoring of impacts of silviculture are scattered and not integrated into research networks, with the consequent losses of opportunities and capacity for action. To increase the scientific and practical impacts of these experiences, it is necessary to establish logical frameworks that harmonize the information and help us to define the most appropriate treatments. In this context, a number of research groups in Spain have produced research achievements and know-how during the last decades that can allow for the improvement in AFM. These groups address the issue of AFM from different fields, such as ecophysiology, ecohydrology and forest ecology, thus resulting in valuable but dispersed expertise. The main objective of this work is to introduce a comprehensive strategy aimed to study the implementation of AFM in Spain. As a first step, a network of 34 experimental sites managed by 14 different research groups is proposed and justified. As a second step, the most important AFM impacts on Mediterranean pines, as one of the most extended natural and planted forest types in Spain, are presented. Finally, open questions dealing with key aspects when attempting to implement an AFM framework are discussed. This study is expected to contribute to better outlining the procedures and steps needed to implement regional frameworks for AFMA.J. Molina is beneficiary of an “APOSTD” fellowship (APOSTD/2019/111) funded
by the Generalitat Valenciana. M. Moreno-de las Heras is beneficiary of a Serra Hunter fellowship (UB-LE-9055) funded by the Generalitat de Catalunya. F.J. Ruiz-Gómez is supported by a
postdoctoral fellowship of the Junta de Andalucía (Sevilla, Spain), and the European Social Fund
2014–2020 Program (DOC_0055). The authors received national and international funding through
the following projects: SILVADAPT.NET (RED2018-102719-T), ESPECTRAMED (CGL2017-86161-R),
Life-FOREST CO2 (LIFE14 CCM/ES/001271), ALTERACLIM (CGL2015-69773-C2-1-P), INERTIA
(PID2019-111332RB-C22-BDV), CEHYRFO-MED (CGL2017-86839-C3-2-R), DEHESACLIM (IB16185),
RESILIENTFORESTS (LIFE17 CCA/ES/000063), Rhysotto (PID2019-106583RB-I00), AGL2017-83828-
C2-2-R, RTI2018-096884-B-C31, ESPAS (CGL2015-65569-R), and caRRRascal (RTI2018-095037-B-I00)
: We thank the financial support from the “Ministerio de Ciencia e Innovación
-Redes de Investigación 2018, Programa Estatal de Generación de Conocimiento y Fortalecimiento
Científico y Tecnológico del Sistema de I + D + I
ANAIS-112. Searching for the annual modulation of dark matter with a 112.5 kg NaI(Tl) detector at the Canfranc Underground Laboratory.
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Design of Force Fields from Data at Finite Temperature
We investigate the problem of how to obtain the force field between atoms of
an experimentally determined structure. We show how this problem can be
efficiently solved, even at finite temperature, where the position of the atoms
differs substantially from the ground state. We apply our method to systems
modeling proteins and demonstrate that the correct potentials can be recovered
even in the presence of thermal noise.Comment: 10 pages, 1 postcript figure, Late
Enantio- and Diastereoselective Nucleophilic Addition of N-tert-Butylhydrazones to Isoquinolinium Ions through Anion-Binding Catalysis
A highly enantio- and diastereoselective thiourea-catalyzed dearomatization of isoquinolines employing N-tert-butylhydrazones as neutral alpha-azo carbanions and masked acyl anion equivalents has been developed. Experimental and computational data supports the generation of highly ordered complexes wherein the chloride behaves as a template for the catalyst, the hydrazone reagent, and the isoquinolinium cation, providing excellent stereocontrol in the formation of two contiguous stereogenic centers. The ensuing selective and high-yielding transformations provide appealing dihydroisoquinoline derivatives
A necklace of dense cores in the high-mass star forming region G35.20-0.74N: ALMA observations
The present study aims at characterizing the massive star forming region
G35.20N, which is found associated with at least one massive outflow and
contains multiple dense cores, one of them recently found associated with a
Keplerian rotating disk. We used ALMA to observe the G35.20N region in the
continuum and line emission at 350 GHz. The observed frequency range covers
tracers of dense gas (e.g. H13CO+, C17O), molecular outflows (e.g. SiO), and
hot cores (e.g. CH3CN, CH3OH). The ALMA 870 um continuum emission map reveals
an elongated dust structure (0.15 pc long and 0.013 pc wide) perpendicular to
the large-scale molecular outflow detected in the region, and fragmented into a
number of cores with masses 1-10 Msun and sizes 1600 AU. The cores appear
regularly spaced with a separation of 0.023 pc. The emission of dense gas
tracers such as H13CO+ or C17O is extended and coincident with the dust
elongated structure. The three strongest dust cores show emission of complex
organic molecules characteristic of hot cores, with temperatures around 200 K,
and relative abundances 0.2-2x10^(-8) for CH3CN and 0.6-5x10^(-6) for CH3OH.
The two cores with highest mass (cores A and B) show coherent velocity fields,
with gradients almost aligned with the dust elongated structure. Those velocity
gradients are consistent with Keplerian disks rotating about central masses of
4-18 Msun. Perpendicular to the velocity gradients we have identified a
large-scale precessing jet/outflow associated with core B, and hints of an
east-west jet/outflow associated with core A. The elongated dust structure in
G35.20N is fragmented into a number of dense cores that may form massive stars.
Based on the velocity field of the dense gas, the orientation of the magnetic
field, and the regularly spaced fragmentation, we interpret this elongated
structure as the densest part of a 1D filament fragmenting and forming massive
stars.Comment: 24 pages, 26 figures, accepted for publication in Astronomy and
Astrophysics (abstract modified to fit arXiv restrictions
Capillaria plica como agente etiológico de hematuria en un perro
Se describen los hallazgos clínicos y hematológicos, diagnóstico y tratamiento de un caso de hematuria y disuria provocado por Capíllaria plica en un perro macho de un año y medio.Clinical picture, haematologic features, diagnostic techniques and treatment protocols are discussed regarding a male dog one year and a half old with hematuria caused by Capillaria plica
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