312 research outputs found

    What role does the LPA1 receptor play in regulating emotional-like behaviours?

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    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

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    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 deg2^2 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, fcontf_{\rm cont}, 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 fcontf_{\rm cont} threshold. M500M_{500} 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-zz performance with an RMS scatter in Δz/(1+z)\Delta z/(1+z) 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 fcontf_{\rm cont} 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 z\sim1.3.Comment: 20 pages, 5 Appendices, 17 figures, submitted to MNRA

    Ultracool dwarfs candidates based on six years of the Dark Energy Survey data

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    We present a sample of 19,583 ultracool dwarf candidates brighter than z 23\leq 23 selected from the Dark Energy Survey DR2 coadd data matched to VHS DR6, VIKING DR5 and AllWISE covering \sim 4,800 deg2deg^2. 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

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    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

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    Recent analyses have found intriguing correlations between the colour (cc) 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 (cc). We find a 3σ3\sigma difference for the size of the mass-step when comparing blue (c<0c < 0) and red (c>0c > 0) SNe. We observe the lowest r.m.s. scatter (0.14\sim 0.14) 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 cc-dependent relationships between Hubble residuals and MstellarM_\mathrm{stellar}, approximating existing dust models, we remove the mass-step from the data but find significant remaining steps in rest-frame URU-R, indicating that current dust modelling based on MstellarM_\mathrm{stellar} may not fully explain the remaining dispersion in SN luminosity. The most dispersion is removed by instead accounting for a cc-dependent relationship between Hubble residuals and global URU-R, resulting in 1σ\leq 1\sigma remaining steps in other environmental properties, suggesting that URU-R provides different information about the environment of SNe Ia to MstellarM_\mathrm{stellar}. This cc-dependent URU-R relation implies that URU-R may be more closely linked to dust, motivating the future inclusion of galaxy URU-R 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

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    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: Hβ\beta lags from the 6-year survey

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    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 RLR-L 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 Hβ\beta from the six-year Australian Dark Energy Survey (OzDES) Reverberation Mapping Program. We successfully recover reverberation lags for eight AGN at 0.12<z<0.710.12<z< 0.71, probing higher redshifts than the bulk of Hβ\beta measurements made to date. Our fit to the RLR-L relation has a slope of α=0.41±0.03\alpha=0.41\pm0.03 and an intrinsic scatter of σ=0.23±0.02\sigma=0.23\pm0.02 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

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    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

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    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

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    <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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