78 research outputs found
Metallicity evolution of AGNs from UV emission-lines based on a new index
We analyzed the evolution of the metallicity of the gas with the redshift for
a sample of AGNs in a very wide redshift range (0<z<4) using ultraviolet
emission-lines from the narrow-line regions (NLRs) and photoionization models.
The new index C43=log(CIV+CIII])/HeII is suggested as a metallicity indicator
for AGNs. Based on this indicator, we confirmed the no metallicity evolution of
NLRs with the redshift pointed out by previous works. We found that metallicity
of AGNs shows similar evolution than the one predicted by cosmic semi-analytic
models of galaxy formation set within the Cold Dark Matter merging hierarchy
(for z < 3). Our results predict a mean metallicity for local objects in
agreement with the solar value (12+log(O/H)=8.69). This value is about the same
that the maximum oxygen abundance value derived for the central parts of local
spiral galaxies. Very low metallicity log(Z/Z_{\odot})~ -0.8 for some objects
in the range 1.5 < z <3 is derived.Comment: 25 pages, 10 figures, accepted MNRA
Polymer Optical Fiber Curvature Measuring Technique Based on Speckle Pattern Image Processing
A self-developed light intensity-modulated curvature measuring principle for the measurement of bending angles within a range from −120 ◦ to +130 ◦ under application of a Polymer Optical Fiber is described in the present work. The determination of the bending angle is based on the graphical analysis of the speckle-pattern that is affected by the curved fiber. The contours of speckles in a defined region of interest in the speckle-pattern are made visible by an edge-detection algorithm and their amount is set in relation to the bending angle. The digital image of a speckle-pattern represents a source of image information that facilitates the further analysis by a variety of image processing techniques. The purpose of this work is the evaluation of a graphical analysis of a speckle-pattern for the curvature measurement. The research incorporates the basic study of general effects on the fiber under curvature until the development of a final measurement setup that facilitates a reliable and precise measurement of the bending angle. Coherent light with a wavelength of 632.8 nm is propagated through a looped Polymer Optical Fiber and received by a 5-Megapixel Charge-Coupled-Device-camera, positioned on the fiber output face. An especially designed acrylic goniometer facilitates the
defined bending of the fiber for different fiber loop configurations. Different fiber arrangements and spatial image filters are evaluated under consideration of precision of bending angle gauging and computational efficiency. A developed digital signal processing routine performs a signal noise reduction and precision improvement for the bending angle measurement. Practical results revealed the existence of a non-linear dependence in static and dynamic operation in the range from −120 ◦ to +130 ◦ between the geometrical arrangements of the fiber, the average pixel intensity, the amount of detected speckle contours and the bending angle. A potential application of the sensor for the measurement of human joint movement and posture in the medical field of rehabilitation is possible. The curvature measurement for an application in the robotic field or industrial application is also convenient
Sulphur abundance determinations in star-forming regions-I: Ionization Correction Factor
In the present work we used a grid of photoionization models combined with
stellar population synthesis models to derive reliable Ionization Correction
Factors (ICFs) for the sulphur in star-forming regions. These models cover a
large range of nebular parameters and yielding ionic abundances in consonance
with those derived through optical and infrared observational data of
star-forming regions. From our theoretical ICFs, we suggested an {\alpha} value
of 3.27 in the classical Stasinska formulae. We compared the total sulphur
abundance in the gas phase of a large sample of objects by using our
Theoretical ICF and other approaches. In average, the differences between the
determinations via the use of the different ICFs considered are similar to the
uncertainties in the S/H estimations. Nevertheless, we noted that for some
objects it could reach up to about 0.3 dex for the low metallicity regime.
Despite of the large scatter of the points, we found a trend of S/O ratio to
decrease with the metallicity, independently of the ICF used to compute the
sulphur total abundance.Comment: Accepted for publication in MNRAS, 21 pages, 8 figures, 5 table
Interaction effects on galaxy pairs with Gemini/GMOS- II: Oxygen abundance gradients
In this paper we derived oxygen abundance gradients from HII regions located
in eleven galaxies in eight systems of close pairs. Long-slit spectra in the
range 4400-7300A were obtained with the Gemini Multi-Object Spec- trograph at
Gemini South (GMOS). Spatial profiles of oxygen abundance in the gaseous phase
along galaxy disks were obtained using calibrations based on strong
emission-lines (N2 and O3N2). We found oxygen gradients signifi- cantly flatter
for all the studied galaxies than those in typical isolated spiral galaxies.
Four objects in our sample, AM1219A, AM1256B, AM 2030A and AM2030B, show a
clear break in the oxygen abundance at galactocentric radius R/R25 between 0.2
and 0.5. For AM1219A and AM1256B we found negative slopes for the inner
gradients, and for AM2030B we found a positive one. In all these three cases
they show a flatter behaviour to the outskirts of the galaxies. For AM2030A, we
found a positive-slope outer gradient while the inner one is almost compatible
with a flat behaviour. A decrease of star forma- tion efficiency in the zone
that corresponds to the oxygen abundance gradient break for AM1219A and AM2030B
was found. For the former, a minimum in the estimated metallicities was found
very close to the break zone that could be associated with a corotation radius.
On the other hand, AM1256B and AM2030A, present a SFR maximum but not an
extreme oxygen abundance value. All the four interacting systems that show
oxygen gradient breakes the extreme SFR values are located very close to break
zones. Hii regions lo- cated in close pairs of galaxies follow the same
relation between the ionization parameter and the oxygen abundance as those
regions in isolated galaxies.Comment: 30 pages, 14 figures, accepted MNRAS, (Figs. 1 and 2 are in low
resolution
Optical and mid-infrared neon abundance determinations in star-forming regions
We employed observational spectroscopic data of star-forming regions compiled
from the literature and photoionization models to analyse the neon ionic
abundances obtained using both optical and mid-infrared emission-lines.
Comparing Ne++/H+ ionic abundances from distinct methods, we found that, in
average, the abundances obtained via IR emission-lines are higher than those
obtained via optical lines by a factor of 4. Photoionization models with
abundance variations along the radius of the hypothetical nebula provide a
possible explanation for a large part of the difference between ionic
abundances via optical and infrared emission-lines. Ionization Correction
Factor (ICF) for the neon is obtained from direct determinations of ionic
fractions using infrared emission-lines. A constant Ne/O ratio (logNe/O \approx
-0.70) for a large range of metallicity, independently of the ICF used to
compute the neon total abundance is derived.Comment: 17 pages, 14 figures, accepted by MNRA
X-rays as dominant excitation mechanism of [Fe ii] and H2 emission lines in active galaxies
We investigate the excitation mechanisms of near-infrared [Fe ii] and H2
emission lines observed in Active Galactic Nuclei (AGNs). We built a
photoionization model grid considering a two-component continuum, one accounts
for the Big Bump component peaking at 1Ryd and another represents the X-ray
source that dominates the continuum emission at high energies. Photoionization
models considering as ionizing source a spectral energy distribution obtained
from photometric data of the Sy 2 Mrk 1066 taken from the literature were
considered. Results of these models were compared with a large sample of
observational long-slit and Integral field Unit (IFU) spectroscopy data of the
nuclear region for a sample of active objects. We found that the correlation
between the observational [Fe ii]{\lambda}1.2570 {\mu}m/Pa{\beta} vs.
H2{\lambda}2.1218 {\mu}m/Br{\gamma} is well reproduced by our models as well as
the relationships that involve the H2 emission line ratios observed in the
spectroscopic data.We conclude that the heating by X-rays produced by active
nuclei can be considered a common and very important mechanism of excitation of
[Fe ii] and H2.Comment: 10 pages, 9 figures, accepted by MNRA
Pilot to policy: statewide dissemination and implementation of evidence-based treatment for traumatized youth
Abstract
Background
A model for statewide dissemination of evidence-based treatment (EBT) for traumatized youth was piloted and taken to scale across North Carolina (NC). This article describes the implementation platform developed, piloted, and evaluated by the NC Child Treatment Program to train agency providers in Trauma-Focused Cognitive Behavioral Therapy using the National Center for Child Traumatic Stress Learning Collaborative (LC) Model on Adoption & Implementation of EBTs. This type of LC incorporates adult learning principles to enhance clinical skills development as part of training and many key implementation science strategies while working with agencies and clinicians to implement and sustain the new practice.
Methods
Clinicians (nβ=β124) from northeastern NC were enrolled in one of two TF-CBT LCs that lasted 12Β months each. During the LC clinicians were expected to take at least two clients through TF-CBT treatment with fidelity and outcomes monitoring by trainers who offered consultation by phone and during trainings. Participating clinicians initiated treatment with 281 clients. The relationship of clinician and client characteristics to treatment fidelity and outcomes was examined using hierarchical linear regression.
Results
One hundred eleven clinicians completed general training on trauma assessment batteries and TF-CBT. Sixty-five clinicians met all mastery and fidelity requirements to meet roster criteria. One hundred fifty-six (55%) clients had fidelity-monitored assessment and TF-CBT. Child externalizing, internalizing, and post-traumatic stress symptoms, as well as parent distress levels, decreased significantly with treatment fidelity moderating child PTSD outcomes. Since this pilot, 11 additional cohorts of TF-CBT providers have been trained to these roster criteria.
Conclusion
Scaling up or outcomes-oriented implementation appears best accomplished when training incorporates: 1) practice-based learning, 2) fidelity coaching, 3) clinical assessment and outcomes-oriented treatment, 4) organizational skill-building to address barriers for agencies, and 5) linking clients to trained clinicians via an online provider roster. Demonstrating clinician performance and client outcomes in this pilot and subsequent cohorts led to legislative support for dissemination of a service array of EBTs by the NC Child Treatment Program
Dopamine Transporter and Reward Anticipation in a Dimensional Perspective : A Multimodal Brain Imaging Study
We would like to thank Christine Baron, Vincent Brulon, StΓ©phane LeHelleix, StΓ©phane Demphel, Claude Comtat, FrΓ©dΓ©ric DollΓ©, Philippe Gervais, and Renaud Maroy from the Service Hospitalier FrΓ©dΓ©ric Joliot for their efficient technical support and 11C radioligand preparation. They thank Marie Prat, Audrey Pepin, and Audrey Mabondo for their help in PET processing and Pr. Maria-Joao Santiago-Ribeiro and Dr Renaud de Beaurepaire for their involvement in the recruitment of participants.Peer reviewedPostprin
Late Replication Domains in Polytene and Non-Polytene Cells of Drosophila melanogaster
In D. melanogaster polytene chromosomes, intercalary heterochromatin (IH) appears as large dense bands scattered in euchromatin and comprises clusters of repressed genes. IH displays distinctly low gene density, indicative of their particular regulation. Genes embedded in IH replicate late in the S phase and become underreplicated. We asked whether localization and organization of these late-replicating domains is conserved in a distinct cell type. Using published comprehensive genome-wide chromatin annotation datasets (modENCODE and others), we compared IH organization in salivary gland cells and in a Kc cell line. We first established the borders of 60 IH regions on a molecular map, these regions containing underreplicated material and encompassing βΌ12% of Drosophila genome. We showed that in Kc cells repressed chromatin constituted 97% of the sequences that corresponded to IH bands. This chromatin is depleted for ORC-2 binding and largely replicates late. Differences in replication timing between the cell types analyzed are local and affect only sub-regions but never whole IH bands. As a rule such differentially replicating sub-regions display open chromatin organization, which apparently results from cell-type specific gene expression of underlying genes. We conclude that repressed chromatin organization of IH is generally conserved in polytene and non-polytene cells. Yet, IH domains do not function as transcription- and replication-regulatory units, because differences in transcription and replication between cell types are not domain-wide, rather they are restricted to small βislandsβ embedded in these domains. IH regions can thus be defined as a special class of domains with low gene density, which have narrow temporal expression patterns, and so displaying relatively conserved organization
Transcriptome Analysis of the Desert Locust Central Nervous System: Production and Annotation of a Schistocerca gregaria EST Database
) displays a fascinating type of phenotypic plasticity, designated as βphase polyphenismβ. Depending on environmental conditions, one genome can be translated into two highly divergent phenotypes, termed the solitarious and gregarious (swarming) phase. Although many of the underlying molecular events remain elusive, the central nervous system (CNS) is expected to play a crucial role in the phase transition process. Locusts have also proven to be interesting model organisms in a physiological and neurobiological research context. However, molecular studies in locusts are hampered by the fact that genome/transcriptome sequence information available for this branch of insects is still limited. EST information is highly complementary to the existing orthopteran transcriptomic data. Since many novel transcripts encode neuronal signaling and signal transduction components, this paper includes an overview of these sequences. Furthermore, several transcripts being differentially represented in solitarious and gregarious locusts were retrieved from this EST database. The findings highlight the involvement of the CNS in the phase transition process and indicate that this novel annotated database may also add to the emerging knowledge of concomitant neuronal signaling and neuroplasticity events. EST data constitute an important new source of information that will be instrumental in further unraveling the molecular principles of phase polyphenism, in further establishing locusts as valuable research model organisms and in molecular evolutionary and comparative entomology
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