2,387 research outputs found
Atomic Processes in Planetary Nebulae and H II Regions
Spectroscopic studies of Planetary Nebulae (PNe) and H {\sc ii} regions have
driven much development in atomic physics. In the last few years the
combination of a generation of powerful observatories, the development of ever
more sophisticated spectral modeling codes, and large efforts on mass
production of high quality atomic data have led to important progress in our
understanding of the atomic spectra of such astronomical objects. In this paper
I review such progress, including evaluations of atomic data by comparisons
with nebular spectra, detection of spectral lines from most iron-peak elements
and n-capture elements, observations of hyperfine emission lines and analysis
of isotopic abundances, fluorescent processes, and new techniques for
diagnosing physical conditions based on recombination spectra. The review is
directed toward atomic physicists and spectroscopists trying to establish the
current status of the atomic data and models and to know the main standing
issues.Comment: 9 pages, 1 figur
Loop Quantization of the Supersymmetric Two-Dimensional BF Model
In this paper we consider the quantization of the 2d BF model coupled to
topological matter. Guided by the rigid supersymmetry this system can be viewed
as a super-BF model, where the field content is expressed in terms of
superfields. A canonical analysis is done and the constraints are then
implemented at the quantum level in order to construct the Hilbert space of the
theory under the perspective of Loop Quantum Gravity methods.Comment: 17 pages, Late
Comparison of engagement and emotional responses of older and younger adults interacting with 3D cultural heritage artefacts on personal devices
The availability of advanced software and less expensive hardware allows museums to preserve and share artefacts digitally. As a result, museums are frequently making their collections accessible online as interactive, 3D models. This could lead to the unique situation of viewing the digital artefact before the physical artefact. Experiencing artefacts digitally outside of the museum on personal devices may affect the user's ability to emotionally connect to the artefacts. This study examines how two target populations of young adults (18–21 years) and the elderly (65 years and older) responded to seeing cultural heritage artefacts in three different modalities: augmented reality on a tablet, 3D models on a laptop, and then physical artefacts. Specifically, the time spent, enjoyment, and emotional responses were analysed. Results revealed that regardless of age, the digital modalities were enjoyable and encouraged emotional responses. Seeing the physical artefacts after the digital ones did not lessen their enjoyment or emotions felt. These findings aim to provide an insight into the effectiveness of 3D artefacts viewed on personal devices and artefacts shown outside of the museum for encouraging emotional responses from older and younger people
N-methyl-N-((1-methyl-5-(3-(1-(2-methylbenzyl)piperidin-4-yl)propoxy)-1H-indol-2-yl)methyl)prop-2-yn-1-amine, a new cholinesterase and monoamine oxidase dual inhibitor
On the basis of N-((5-(3-(1-benzylpiperidin-4-yl)propoxy)-1-methyl-1H-indol-2-yl)methyl)-N-methylprop-2-yn-1-amine (II, ASS234) and QSAR predictions, in this work we have designed, synthesized, and evaluated a number of new indole derivatives from which we have identified N-methyl-N-((1-methyl-5-(3-(1-(2-methylbenzyl)piperidin-4-yl)propoxy)-1H-indol-2-yl)methyl)prop-2-yn-1-amine (2, MBA236) as a new cholinesterase and monoamine oxidase dual inhibitor.PostprintPostprintPeer reviewe
Vegetation pattern modulates ground arthropod diversity in semi-arid Mediterranean steppes
The ecological functioning of dryland ecosystems is closely related to the spatial pattern of the vegetation, which is typically structured in patches. Ground arthropods mediate key soil functions and ecological processes, yet little is known about the influence of dryland vegetation pattern on their abundance and diversity. Here, we investigate how patch size and cover, and distance between patches relate to the abundance and diversity of meso-and microarthropods in semi-arid steppes. We found that species richness and abundance of ground arthropods exponentially increase with vegetation cover, patch size, and patch closeness. The communities under vegetation patches mainly respond to patch size, while the communities in the bare-soil interpatches are mostly controlled by the average distance between patches, independently of the concurrent changes in vegetation cover. Large patches seem to play a critical role as reserve and source of ground arthropod diversity. Our results suggest that decreasing vegetation cover and/or changes in vegetation pattern towards small and over-dispersed vegetation patches can fast lead to a significant loss of ground arthropods diversity in drylands
Particle production azimuthal asymmetries in a clustering of color sources model
The collective interactions of many partons in the first stage of the
collisions is the usual accepted explanation of the sizable elliptical flow.
The clustering of color sources provides a framework of partonic interactions.
In this scheme, we show a reasonable agreement with RHIC data for pT<1.5 GeV/c
in both the dependence of v2 transverse momentum and in the shape of the
nuclear modified factor on the azimuthal angle for different centralities. We
show the predictions at LHC energies for Pb-Pb. In the case of proton-proton
collisions a sizable v2 is obtained at this energy.Comment: To appear in Journal of Physics
A combined optical/infrared spectral diagnostic analysis of the HH1 jet
Complete flux-calibrated spectra covering the spectral range from 6000 A to
2.5 um have been obtained along the HH1 jet and analysed in order to explore
the potential of a combined optical/near-IR diagnostic applied to jets from
young stellar objects. Important physical parameters have been derived along
the jet using various diagnostic line ratios. This multi-line analysis shows,
in each spatially unresolved knot, the presence of zones at different
excitation conditions, as expected from the cooling layers behind a shock
front. In particular, a density stratification in the jet is evident from
ratios of various lines of different critical density. In particular, [FeII]
lines originate in a cooling layer located at larger distances from the shock
front than that generating the optical lines, where the compression is higher
and the temperature is declining. The derived parameters were used to measure
the mass flux along the jet, adopting different procedures, the advantages and
limitations of which are discussed. dM/dt is high in the initial part of the
flow but decreases by about an order of magnitude further out. Conversely, the
mass flux associated with the warm molecular material is low and does not show
appreciable variations along the jet. We suggest that part of the mass flux in
the external regions is not revealed in optical and IR lines because it is
associated with a colder atomic component, which may be traced by the far-IR [O
I]63 um line.
Finally, we find that the gas-phase abundance of refractory species is lower
than the solar value suggesting that a significant fraction of dust grains may
still be present in the jet beam.Comment: Accepted on Astronomy & Astrophysic
A Sunspot Catalog for the Period 1952-1986 from Observations Made at the Madrid Astronomical Observatory
Sunspot catalogs are very useful for studying the solar activity of the
recent past. In this context, a catalog covering more than three solar cycles
made by the astronomers of the Madrid Astronomical Observatory in Spain
(nowadays, the National Astronomical Observatory) from 1952 until 1986 has been
recovered. Moreover, a machine-readable version of this catalog has been made
available. We have recovered abundant metadata and studied the reliability of
this dataset by comparing it with other sunspot catalogs.Comment: 21 pages, 10 figures, accepted for publication in Solar Physic
Seudomicetoma dermatofítico en un gato persa : aspectos clínicos, patológicos y evolutivos
En este trabajo presentamos los aspectos clínicos, anatomopatológicos y evolutivos de un caso de dermatitis piogranulomatosa múltiple causada por hongos del género Microsporum, también conocida como seudomicetoma dermatofítico, en un gato persa, no castrado, de un año de edad al comienzo de la enfermedad. Las lesiones se caracterizaron macroscópicamente por la formación de numerosos nódulos de diferentes tamaños, localizados en la cabeza y antebrazo derecho, extendiéndose posteriormente a zona dorso lateral del tronco. La evolución de estos nódulos, que se generalizaron en algo menos de un mes, era hacia la coalescencia y fistulización, con descarga de un material grumoso blanco-grisáceo. El estudio histopatológico reveló una dermatitis piogranulomatosa, supeficial y profunda, caracterizada por presentar en el centro de los granulomas agregados de hongos septados inmersos en una matriz acidófila. La extirpación quirúrgica de un gran número de nódulos proporcionó mejorías transitorias, aunque reaparecieron nuevas lesiones. En este trabajo se describe la evolución tras dos años de seguimiento clínico. Tras el tratamiento con griseofulvina no se detectan nuevas lesiones después de 6 meses de su aplicación y seguimiento.This paper reports the clinical and histopathological features of a case of pyogranulomatous dermatitis caused by Microsporum fungi, a condition also known as dermatophyte pseudomycetoma, in a eneyear-old Persian cat. Grossly apparent fistulized nodules of varying sizes displaying a granular discharge were localized on the head, back, elbow and tail. Microscopic analysis revealed a deep piogranulomatous dermatitis characterized by centrally-located clusters of fungi within an acidophilic matrix. In just under a month, nodules had beco me generalized. Partial surgical excision and non-specific treatment provided temporary improvement, but new lesions subsequentlyappeared
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