312 research outputs found
What role does the LPA1 receptor play in regulating emotional-like behaviours?
The LPA1 receptor is one of the six characterized G protein-coupled receptors (LPA1–6)
through which lysophosphatidic acid acts as an intercellular signalling molecule. It has been
proposed that this receptor has a role in controlling anxiety-like behaviours and in the
detrimental consequences of stress. In general, the neurobiological mechanism of fear extinction
is strikingly similar to that of the adaptative stress response (distress regulation), sharing similar
neuroanatomical, neuroendocrine, and neurochemical basis. Inadequate control of the stress
response could precipitate or provoke anxiety disorders. In this context, we tried to elucidate the
LPA1 receptor involvement in emotional regulation. For this purpose, we first examined fear
extinction, a type of emotional regulation, in normal wild-type (wt) and maLPA1-null mice
using two different extinction procedures (cued fear extinction and contextual fear extinction).
Additionally, to study the role of the LPA1 receptor in the absence of developmental
abnormalities induced by its permanent loss, the effect of the LPA1 antagonist Ki16425
administration was examined in contextual fear extinction on wild-type mice. Next, we studied
the consequences of the absence of the LPA1 receptor in two key areas involved in emotional
regulation, characterizing the structure and GABAergic composition of the medial prefrontal
cortex (mPFC) and the amygdala by immunohistochemical detection of neuron specific nuclear
protein (NeuN), GABA-positive cells and calcium-binding proteins (calretinin (CR),
parvalbumin (PV), and calbindin (CB)). Lastly, we examined the corticosterone response and
the expression of a marker of neuronal activity, c-Fos protein, in the amygdala and the mPFC
after acute stress. Our results revealed that lack of the LPA1-receptor induces exaggerated
amygdala reactivity and endocrine responses to emotional stimuli (e.g., an acute episode of
stress), revealing a role of the LPA1 receptor in regulating emotional-like behaviours.
Considering that a reduction of GABAergic inhibitory control in the amygdala may be a
common mechanism to generate a heightened emotional state, the abnormal emotional response
reported in LPA1-null mice could be explained, at least in part, by a significant reduction of
GABAérgic composition of the amygdala observed in these animals.
Taking together, the LPA1 receptor is involved in emotional behaviours and in the anatomical
integrity of the corticolimbic circuit, the deregulation of which may be a susceptibility factor for anxiety disorders and a potential therapeutic target for the treatment of these diseases.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
The MADPSZ catalogue of Planck clusters over the DES region: extending to lower mass and higher redshift
We present the first systematic follow-up of Planck Sunyaev-Zeldovich effect
(SZE) selected candidates down to signal-to-noise (S/N) of 3 over the 5000
deg covered by the Dark Energy Survey. Using the MCMF cluster confirmation
algorithm, we identify optical counterparts, determine photometric redshifts
and richnesses and assign a parameter, , that reflects the
probability that each SZE-optical pairing represents a real cluster rather than
a random superposition of physically unassociated systems. The new MADPSZ
cluster catalogue consists of 1092 MCMF confirmed clusters and has a purity of
85%. We present the properties of subsamples of the MADPSZ catalogue that have
purities ranging from 90% to 97.5%, depending on the adopted
threshold. halo mass estimates, redshifts, richnesses, and optical
centers are presented for all MADPSZ clusters. The MADPSZ catalogue adds 828
previously unknown Planck identified clusters over the DES footprint and
provides redshifts for an additional 50 previously published Planck selected
clusters with S/N>4.5. Using the subsample with spectroscopic redshifts, we
demonstrate excellent cluster photo- performance with an RMS scatter in
of 0.47%. Our MCMF based analysis allows us to infer the
contamination fraction of the initial S/N>3 Planck selected candidate list,
which is 50%. We present a method of estimating the completeness of the MADPSZ
cluster sample and selected subsamples. In comparison to the
previously published Planck cluster catalogues. this new S/N 3 MCMF
confirmed cluster catalogue populates the lower mass regime at all redshifts
and includes clusters up to z1.3.Comment: 20 pages, 5 Appendices, 17 figures, submitted to MNRA
Ultracool dwarfs candidates based on six years of the Dark Energy Survey data
We present a sample of 19,583 ultracool dwarf candidates brighter than z
selected from the Dark Energy Survey DR2 coadd data matched to VHS
DR6, VIKING DR5 and AllWISE covering 4,800 . The ultracool
candidates were first pre-selected based on their (i-z), (z-Y), and (Y-J)
colours. They were further classified using a method that compares their
optical, near-infrared and mid-infrared colours against templates of M, L and T
dwarfs. 14,099 objects are presented as new L and T candidates and the
remaining objects are from the literature, including 5,342 candidates from our
previous work. Using this new and deeper sample of ultracool dwarf candidates
we also present: 20 new candidate members to nearby young moving groups (YMG)
and associations, variable candidate sources and four new wide binary systems
composed of two ultracool dwarfs. Finally, we also show the spectra of twelve
new ultracool dwarfs discovered by our group and presented here for the first
time. These spectroscopically confirmed objects are a sanity check of our
selection of ultracool dwarfs and photometric classification method.Comment: 18 pages, 10 figures, 7 tables. Accepted for publication in MNRA
Photometric Properties of Jupiter Trojans Detected by the Dark Energy Survey
The Jupiter Trojans are a large group of asteroids that are coorbiting with Jupiter near its L4 and L5 Lagrange points. The study of Jupiter Trojans is crucial for testing different models of planet formation that are directly related to our understanding of solar system evolution. In this work, we select known Jupiter Trojans listed by the Minor Planet Center from the full six years data set (Y6) of the Dark Energy Survey (DES) to analyze their photometric properties. The DES data allow us to study Jupiter Trojans with a fainter magnitude limit than previous studies in a homogeneous survey with griz band measurements. We extract a final catalog of 573 unique Jupiter Trojans. Our sample include 547 asteroids belonging to L5. This is one of the largest analyzed samples for this group. By comparing with the data reported by other surveys we found that the color distribution of L5 Trojans is similar to that of L4 Trojans. We find that L5 Trojans' g - i and g - r colors become less red with fainter absolute magnitudes, a trend also seen in L4 Trojans. Both the L4 and L5 clouds consistently show such a color-size correlation over an absolute magnitude range 11 < H < 18. We also use DES colors to perform taxonomic classifications. C- and P-type asteroids outnumber D-type asteroids in the L5 Trojans DES sample, which have diameters in the 5-20 km range. This is consistent with the color-size correlation
Concerning Colour: The Effect of Environment on Type Ia Supernova Colour in the Dark Energy Survey
Recent analyses have found intriguing correlations between the colour ()
of type Ia supernovae (SNe Ia) and the size of their mass-step, the
relationship between host galaxy stellar mass and Hubble residual. These
analyses suggest that the underlying cause of this relationship is dust. Using
a sample of 675 photometrically-classified SNe Ia from the Dark Energy Survey
5-year sample, we study the differences in Hubble residual for a variety of
host and local properties for subsamples split by their colour (). We find a
difference for the size of the mass-step when comparing blue () and red () SNe. We observe the lowest r.m.s. scatter ()
in Hubble residual for blue SNe in low mass or blue environments, suggesting
that these objects provide the most homogeneous sample for cosmological
analyses. By fitting for -dependent relationships between Hubble residuals
and , approximating existing dust models, we remove the
mass-step from the data but find significant remaining steps in rest-frame
, indicating that current dust modelling based on may
not fully explain the remaining dispersion in SN luminosity. The most
dispersion is removed by instead accounting for a -dependent relationship
between Hubble residuals and global , resulting in
remaining steps in other environmental properties, suggesting that
provides different information about the environment of SNe Ia to
. This -dependent relation implies that may
be more closely linked to dust, motivating the future inclusion of galaxy
colour in the correction for SN distance biases.Comment: 18 pages, 8 figures. Submitted to MNRA
Building an Efficient Cluster Cosmology Software Package for Modeling Cluster Counts and Lensing
We introduce a software suite developed for galaxy cluster cosmological
analysis with the Dark Energy Survey Data. Cosmological analyses based on
galaxy cluster number counts and weak-lensing measurements need efficient
software infrastructure to explore an increasingly large parameter space, and
account for various cosmological and astrophysical effects. Our software
package is designed to model the cluster observables in a wide-field optical
survey, including galaxy cluster counts, their averaged weak-lensing masses, or
the cluster's averaged weak-lensing radial signals. To ensure maximum
efficiency, this software package is developed in C++ in the CosmoSIS software
framework, making use of the CUBA integration library. We also implement a
testing and validation scheme to ensure the quality of the package. We
demonstrate the effectiveness of this development by applying the software to
the Dark Energy Survey Year 1 galaxy cluster cosmological data sets, and
acquired cosmological constraints that are consistent with the fiducial Dark
Energy Survey analysis
OzDES Reverberation Mapping Program: H lags from the 6-year survey
Reverberation mapping measurements have been used to constrain the
relationship between the size of the broad-line region and luminosity of active
galactic nuclei (AGN). This relation is used to estimate single-epoch
virial black hole masses, and has been proposed for use to standardise AGN to
determine cosmological distances. We present reverberation measurements made
with H from the six-year Australian Dark Energy Survey (OzDES)
Reverberation Mapping Program. We successfully recover reverberation lags for
eight AGN at , probing higher redshifts than the bulk of H
measurements made to date. Our fit to the relation has a slope of
and an intrinsic scatter of dex. The
results from our multi-object spectroscopic survey are consistent with previous
measurements made by dedicated source-by-source campaigns, and with the
observed dependence on accretion rate. Future surveys, including LSST, TiDES
and SDSS-V, which will be revisiting some of our observed fields, will be able
to build on the results of our first-generation multi-object reverberation
mapping survey.Comment: Submitted to MNRA
The PSZ-MCMF catalogue of Planck clusters over the des region
We present the first systematic follow-up of Planck Sunyaev–Zeldovich effect (SZE) selected candidates down to signal-to-noise (S/N) of 3 over the 5000 deg2 covered by the Dark Energy Survey. Using the MCMF cluster confirmation algorithm, we identify optical counterparts, determine photometric redshifts, and richnesses and assign a parameter, fcont, that reflects the probability that each SZE-optical pairing represents a random superposition of physically unassociated systems rather than a real cluster. The new PSZ-MCMF cluster catalogue consists of 853 MCMF confirmed clusters and has a purity of 90 per cent. We present the properties of subsamples of the PSZ-MCMF catalogue that have purities ranging from 90 per cent to 97.5 per cent, depending on the adopted fcont threshold. Halo mass estimates M500, redshifts, richnesses, and optical centres are presented for all PSZ-MCMF clusters. The PSZ-MCMF catalogue adds 589 previously unknown Planck identified clusters over the DES footprint and provides redshifts for an additional 50 previously published Planck-selected clusters with S/N>4.5. Using the subsample with spectroscopic redshifts, we demonstrate excellent cluster photo-z performance with an RMS scatter in Δz/(1 + z) of 0.47 per cent. Our MCMF based analysis allows us to infer the contamination fraction of the initial S/N>3 Planck-selected candidate list, which is ∼50 per cent. We present a method of estimating the completeness of the PSZ-MCMF cluster sample. In comparison to the previously published Planck cluster catalogues, this new S/N>3 MCMF confirmed cluster catalogue populates the lower mass regime at all redshifts and includes clusters up to z∼1.3
DeepZipper. II. Searching for Lensed Supernovae in Dark Energy Survey Data with Deep Learning
Gravitationally lensed supernovae (LSNe) are important probes of cosmic expansion, but they remain rare and difficult to find. Current cosmic surveys likely contain 5-10 LSNe in total while next-generation experiments are expected to contain several hundred to a few thousand of these systems. We search for these systems in observed Dark Energy Survey (DES) five year SN fields—10 3 sq. deg. regions of sky imaged in the griz bands approximately every six nights over five years. To perform the search, we utilize the DeepZipper approach: a multi-branch deep learning architecture trained on image-level simulations of LSNe that simultaneously learns spatial and temporal relationships from time series of images. We find that our method obtains an LSN recall of 61.13% and a false-positive rate of 0.02% on the DES SN field data. DeepZipper selected 2245 candidates from a magnitude-limited (m i < 22.5) catalog of 3,459,186 systems. We employ human visual inspection to review systems selected by the network and find three candidate LSNe in the DES SN fields
Procalcitonin levels in acute exacerbation of COPD admitted in ICU: a prospective cohort study
<p>Abstract</p> <p>Background</p> <p>Antibiotics are recommended for severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD) admitted to intensive care units (ICU). Serum procalcitonin (PCT) could be a useful tool for selecting patients with a lower probability of developing bacterial infection, but its measurement has not been investigated in this population.</p> <p>Methods</p> <p>We conducted a single center prospective cohort study in consecutive COPD patients admitted to the ICU for AECOPD between September 2005 and September 2006. Sputum samples or tracheal aspirates were tested for the presence of bacteria and viruses. PCT levels were measured at the time of admittance, six hours, and 24 hours using a sensitive immunoassay.</p> <p>Results</p> <p>Thirty nine AECOPD patients were included, 31 of which (79%) required a ventilator support at admission. The median [25%–75% interquartile range] PCT level, assessed in 35/39 patients, was: 0.096 μg/L [IQR, 0.065 to 0.178] at the time of admission, 0.113 μg/L [IQR, 0.074 to 0.548] at six hours, and 0.137 μg/L [IQR, 0.088 to 0.252] at 24 hours. The highest PCT (PCTmax) levels were less than 0.1 μg/L in 14/35 (40%) patients and more than 0.25 μg/L in 10/35 (29%) patients, suggesting low and high probability of bacterial infection, respectively. Five species of bacteria and nine species of viruses were detected in 12/39 (31%) patients. Among the four patients positive for <it>Pseudomonas aeruginosa</it>, one had a PCTmax less than 0.25 μg/L and three had a PCTmax less than 0.1 μg/L. The one patient positive for <it>Haemophilus influenzae </it>had a PCTmax more than 0.25 μg/L. The presence or absence of viruses did not influence PCT at time of admission (0.068 vs 0.098 μg/L respectively, <it>P </it>= 0.80).</p> <p>Conclusion</p> <p>The likelihood of bacterial infection is low among COPD patients admitted to ICU for AECOPD (40% with PCT < 0.1 μg/L) suggesting a possible inappropriate use of antibiotics. Further studies are necessary to assess the impact of a procalcitonin-based therapeutic strategy in critically ill COPD patients.</p
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