693 research outputs found
Velocity vectors of a quiescent prominence observed by Hinode/SOT and the MSDP (Meudon)
The dynamics of prominence fine structures is a challenge to understand the
formation of cool plasma prominence embedded in the hot corona. Recent
observations from the high resolution Hinode/SOT telescope allow us to compute
velocities perpendicularly to the line-of-sight or transverse velocities.
Combining simultaneous observations obtained in H-alpha with Hinode/SOT and the
MSDP spectrograph operating in the Meudon solar tower we derive the velocity
vectors of a quiescent prominence. The velocities perpendicular to the
line-of-sight are measured by time slice technique, the Dopplershifts by the
bisector method. The Dopplershifts of bright threads derived from the MSDP
reach 15 km/s at the edges of the prominence and are between +/- 5 km/s in the
center of the prominence. Even though they are minimum values due to seeing
effect, they are of the same order as the transverse velocities. These
measurements are very important because they suggest that the
verticalstructures shown in SOT may not be real vertical magnetic structures in
the sky plane. The vertical structures could be a pile up of dips in more or
less horizontal magnetic field lines in a 3D perspective, as it was proposed by
many MHD modelers. In our analysis we also calibrate the Hinode H-alpha data
using MSDP observations obtained simultaneously.Comment: 7 pages, 7 figures, submitted to A &
On mesogranulation, network formation and supergranulation
We present arguments which show that in all likelihood mesogranulation is not
a true scale of solar convection but the combination of the effects of both
highly energetic granules, which give birth to strong positive divergences
(SPDs) among which we find exploders, and averaging effects of data processing.
The important role played by SPDs in horizontal velocity fields appears in the
spectra of these fields where the scale 4 Mm is most energetic; we
illustrate the effect of averaging with a one-dimensional toy model which shows
how two independent non-moving (but evolving) structures can be transformed
into a single moving structure when time and space resolution are degraded.
The role of SPDs in the formation of the photospheric network is shown by
computing the advection of floating corks by the granular flow. The coincidence
of the network bright points distribution and that of the corks is remarkable.
We conclude with the possibility that supergranulation is not a proper scale of
convection but the result of a large-scale instability of the granular flow,
which manifests itself through a correlation of the flows generated by SPDs.Comment: 10 pages, 11 figures, to appear in Astronomy and Astrophysic
Induction of Phase 2 Antioxidant Enzymes by Broccoli Sulforaphane: Perspectives in Maintaining the Antioxidant Activity of Vitamins A, C, and E
Consumption of fruits and vegetables is recognized as an important part of a healthy diet. Increased consumption of cruciferous vegetables in particular has been associated with a decreased risk of several degenerative and chronic diseases, including cardiovascular disease and certain cancers. Members of the cruciferous vegetable family, which includes broccoli, Brussels sprouts, cauliflower, and cabbage, accumulate significant concentrations of glucosinolates, which are metabolized in vivo to biologically active isothiocyanates (ITCs). The ITC sulforaphane, which is derived from glucoraphanin, has garnered particular interest as an indirect antioxidant due to its extraordinary ability to induce expression of several enzymes via the KEAP1/Nrf2/ARE pathway. Nrf2/ARE gene products are typically characterized as Phase II detoxification enzymes and/or antioxidant (AO) enzymes. Over the last decade, human clinical studies have begun to provide in vivo evidence of both Phase II and AO enzyme induction by SF. Many AO enzymes are redox cycling enzymes that maintain redox homeostasis and activity of free radical scavengers such as vitamins A, C, and E. In this review, we present the existing evidence for induction of PII and AO enzymes by SF, the interactions of SF-induced AO enzymes and proposed maintenance of the essential vitamins A, C, and E, and, finally, the current view of genotypic effects on ITC metabolism and AO enzyme induction and function
Nuevo Ruscinomys (Rodentia, Mammalia) en el Mioceno Superior de la región de Teruel (España)
This is a study about a new forme of Ruscinomys. It is characterized by the extraordinary development of the protocone of the first upper molar, which gives it a much greater width than that of its homonyme Ruscinomys schaubi from the same site at Aljezar B. Clear discriminating morphological characteristics have not been found in the other dental pieces. Those molars which have a width clearly falling outside the normal distribution of Ruscinomys schaubi are attributed to the new species.Se presenta el estudio de una nueva forma de Ruscinomys. Se caracteriza por el extraordinario desarrollo del protocono del primer molar superior, lo que le proporciona una anchura mucho mayor que la de su homónimo de Ruscinomys schaubi del mismo yacimiento del Ajezar B. No se han hallado en las restantes piezas dentarias caracteres morfológicos claros de discriminación. Se atribuyen a la nueva especie los molares cuya anchura sale claramente fuera del área normal de las distribuciones de R. schaubi
The solar chromosphere at high resolution with IBIS. I. New insights from the Ca II 854.2 nm line
(Abridged)
Aims: In this paper, we seek to establish the suitability of imaging
spectroscopy performed in the Ca II 854.2 nm line as a means to investigate the
solar chromosphere at high resolution.
Methods: We utilize monochromatic images obtained with the Interferometric
BIdimensional Spectrometer (IBIS) at multiple wavelengths within the Ca II
854.2 nm line and over several quiet areas. We analyze both the morphological
properties derived from narrow-band monochromatic images and the average
spectral properties of distinct solar features such as network points,
internetwork areas and fibrils.
Results: The spectral properties derived over quiet-Sun targets are in full
agreement with earlier results obtained with fixed-slit spectrographic
observations, highlighting the reliability of the spectral information obtained
with IBIS. Furthermore, the very narrowband IBIS imaging reveals with much
clarity the dual nature of the Ca II 854.2 nm line: its outer wings gradually
sample the solar photosphere, while the core is a purely chromospheric
indicator. The latter displays a wealth of fine structures including bright
points, akin to the Ca II H2V and K2V grains, as well as fibrils originating
from even the smallest magnetic elements. The fibrils occupy a large fraction
of the observed field of view even in the quiet regions, and clearly outline
atmospheric volumes with different dynamical properties, strongly dependent on
the local magnetic topology. This highlights the fact that 1-D models
stratified along the vertical direction can provide only a very limited
representation of the actual chromospheric physics.Comment: 13 pages, 8 figures. Accepted in A&A. Revised version after referee's
comments. New Fig. 1 and 7. Higher quality figures in
http://www.arcetri.astro.it/~gcauzzi/papers/ibis.caii.pd
Estimation of solar prominence magnetic fields based on the reconstructed 3D trajectories of prominence knots
We present an estimation of the lower limits of local magnetic fields in
quiescent, activated, and active (surges) promineces, based on reconstructed
3-dimensional (3D) trajectories of individual prominence knots. The 3D
trajectories, velocities, tangential and centripetal accelerations of the knots
were reconstructed using observational data collected with a single
ground-based telescope equipped with a Multi-channel Subtractive Double Pass
imaging spectrograph. Lower limits of magnetic fields channeling observed
plasma flows were estimated under assumption of the equipartition principle.
Assuming approximate electron densities of the plasma n_e = 5*10^{11} cm^{-3}
in surges and n_e = 5*10^{10} cm^{-3} in quiescent/activated prominences, we
found that the magnetic fields channeling two observed surges range from 16 to
40 Gauss, while in quiescent and activated prominences they were less than 10
Gauss. Our results are consistent with previous detections of weak local
magnetic fields in the solar prominences.Comment: 14 pages, 12 figures, 1 tabl
The prediction of pouch of Douglas obliteration using offline analysis of the transvaginal ultrasound ‘sliding sign’ technique: inter- and intra-observer reproducibility
Areca catechu-(Betel-nut)-induced whole transcriptome changes in a human monocyte cell line that may have relevance to diabetes and obesity; a pilot study.
BACKGROUND: Betel-nut consumption is the fourth most common addictive habit globally and there is good evidence linking the habit to obesity, type 2 diabetes (T2D) and the metabolic syndrome. The aim of our pilot study was to identify gene expression relevant to obesity, T2D and the metabolic syndrome using a genome-wide transcriptomic approach in a human monocyte cell line incubated with arecoline and its nitrosated products. RESULTS: The THP1 monocyte cell line was incubated separately with arecoline and 3-methylnitrosaminopropionaldehyde (MNPA) in triplicate for 24 h and pooled cDNA indexed paired-end libraries were sequenced (Illumina NextSeq 500). After incubation with arecoline and MNPA, 15 and 39 genes respectively had significant changes in their expression (q < 0.05, log fold change 1.5). Eighteen of those genes have reported associations with T2D and obesity in humans; of these genes there was most marked evidence for CLEC10A, MAPK8IP1, NEGR1, NQ01 and INHBE genes. CONCLUSIONS: Our preliminary studies have identified a large number of genes relevant to obesity, T2D and metabolic syndrome whose expression was changed significantly in human TPH1 cells following incubation with betel-nut derived arecoline or with MNPA. These findings require validation by further cell-based work and investigation amongst betel-chewing communities
Development and benchmarking of a dose rate engine for raster-scanned FLASH helium ions
Background: Radiotherapy with charged particles at high dose and ultra-high dose rate (uHDR) is a promising technique to further increase the therapeutic index of patient treatments. Dose rate is a key quantity to predict the so-called FLASH effect at uHDR settings. However, recent works introduced varying calculation models to report dose rate, which is susceptible to the delivery method, scanning path (in active beam delivery) and beam intensity. Purpose: This work introduces an analytical dose rate calculation engine for raster scanned charged particle beams that is able to predict dose rate from the irradiation plan and recorded beam intensity. The importance of standardized dose rate calculation methods is explored here. Methods: Dose is obtained with an analytical pencil beam algorithm, using pre-calculated databases for integrated depth dose distributions and lateral penumbra. Dose rate is then calculated by combining dose information with the respective particle fluence (i.e., time information) using three dose-rate-calculation models (mean, instantaneous, and threshold-based). Dose rate predictions for all three models are compared to uHDR helium ion beam (145.7 MeV/u, range in water of approximatively 14.6 cm) measurements performed at the Heidelberg Ion Beam Therapy Center (HIT) with a diamond-detector prototype. Three scanning patterns (scanned or snake-like) and four field sizes are used to investigate the dose rate differences. Results: Dose rate measurements were in good agreement with in-silico generated distributions using the here introduced engine. Relative differences in dose rate were below 10% for varying depths in water, from 2.3 to 14.8 cm, as well as laterally in a near Bragg peak area. In the entrance channel of the helium ion beam, dose rates were predicted within 7% on average for varying irradiated field sizes and scanning patterns. Large differences in absolute dose rate values were observed for varying calculation methods. For raster-scanned irradiations, the deviation between mean and threshold-based dose rate at the investigated point was found to increase with the field size up to 63% for a 10 mm × 10 mm field, while no significant differences were observed for snake-like scanning paths. Conclusions: This work introduces the first dose rate calculation engine benchmarked to instantaneous dose rate, enabling dose rate predictions for physical and biophysical experiments. Dose rate is greatly affected by varying particle fluence, scanning path, and calculation method, highlighting the need for a consensus among the FLASH community on how to calculate and report dose rate in the future. The here introduced engine could help provide the necessary details for the analysis of the sparing effect and uHDR conditions
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