We present a strong lensing analysis of four massive galaxy clusters imaged with the Hubble Space Telescope in the Reionization Lensing Cluster Survey. We use a light-traces-mass technique to uncover ...sets of multiple images and constrain the mass distribution of the clusters. These mass models are the first published for Abell S295 and MACS J0159.8-0849 and are improvements over previous models for Abell 697 and MACS J0025.4-1222. Our analysis for MACS J0025.4-1222 and Abell S295 shows a bimodal mass distribution supporting the merger scenarios proposed for these clusters. The updated model for MACS J0025.4-1222 suggests a substantially smaller critical area than previously estimated. For MACS J0159.8-0849 and Abell 697, we find a single peak and relatively regular morphology revealing fairly relaxed clusters. Despite being less prominent lenses, three of these clusters seem to have lensing strengths, i.e., cumulative area above certain magnification, similar to those of the Hubble Frontier Fields clusters (e.g., A( > 5) ∼ 1-3 arcmin2, A( > 10) ∼ 0.5-1.5 arcmin2), which in part can be attributed to their merging configurations. We make our lens models publicly available through the Mikulski Archive for Space Telescopes. Finally, using Gemini-N/GMOS spectroscopic observations, we detect a single emission line from a high-redshift J125 25.7 galaxy candidate lensed by Abell 697. While we cannot rule out a lower-redshift solution, we interpret the line as Ly at z = 5.800 0.001, in agreement with its photometric redshift and dropout nature. Within this scenario, we measure a Ly rest-frame equivalent width of 52 22 and an observed Gaussian width of 117 15 km s−1.
Strong gravitational lensing (SL) is a powerful means of mapping the distribution of dark matter. In this work, we perform an SL analysis of the prominent X-ray cluster RXJ0152.7-1357 (z = 0.83, also ...known as CL0152.7-1357) in Hubble Space Telescope images, taken in the framework of the Reionization Lensing Cluster Survey (RELICS). On top of a previously known z = 3.93 galaxy multiply imaged by RXJ0152.7-1357, for which we identify an additional multiple image, guided by a light-traces-mass approach, we identify seven new sets of multiply imaged background sources lensed by this cluster, spanning the redshift range 1.79-3.93. A total of 25 multiple images are seen over a small area of ∼0.4 arcmin2, allowing us to put relatively high-resolution constraints on the inner matter distribution. Although modestly massive, the high degree of substructure, together with its very elongated shape, makes RXJ0152.7-1357 a very efficient lens for its size. This cluster also comprises the third-largest sample of z ∼ 6-7 candidates in the RELICS survey. Finally, we present a comparison of our resulting mass distribution and magnification estimates with those from a Lenstool model. These models are made publicly available through the Mikulski Archive for Space Telescopes.
Major depressive disorder (MDD) is a prevalent health problem with complex pathophysiology that is not clearly understood. Prior work has implicated the hippocampus in MDD, but how hippocampal ...subfields influence or are affected by MDD requires further characterization with high-resolution data. This will help ascertain the accuracy and reproducibility of previous subfield findings in depression as well as correlate subfield volumes with MDD symptom scores. The objective of this study was to assess volumetric differences in hippocampal subfields between MDD patients globally and healthy controls (HC) as well as between a subset of treatment-resistant depression (TRD) patients and HC using automatic segmentation of hippocampal subfields (ASHS) software and ultra-high field MRI.
Thirty-five MDD patients and 28 HC underwent imaging using 7-Tesla MRI. ASHS software was applied to the imaging data to perform automated hippocampal segmentation and provide volumetrics for analysis. An exploratory analysis was also performed on associations between symptom scores for diagnostic testing and hippocampal subfield volumes.
Compared to HC, MDD and TRD patients showed reduced right-hemisphere CA2/3 subfield volume (
= 0.01,
= 0.31 and
= 0.3,
= 0.44, respectively). Additionally, negative associations were found between subfield volumes and life-stressor checklist scores, including left CA1 (
= 0.041,
= 0.419), left CA4/DG (
= 0.010,
= 0.584), right subiculum total (
= 0.038,
= 0.354), left hippocampus total (
= 0.015,
= 0.134), and right hippocampus total (
= 0.034,
= 0.110). Caution should be exercised in interpreting these results due to the small sample size and low power.
Determining biomarkers for MDD and TRD pathophysiology through segmentation on high-resolution MRI data and understanding the effects of stress on these regions can enable better assessment of biological response to treatment selection and may elucidate the underlying mechanisms of depression.
We make use of a semi-analytic cosmological model that includes simple prescriptions for dust attenuation and emission to make predictions for the observable and physical properties of galaxies that ...may be detected by the recently launched Herschel
Space Observatory in deep fields such as Great Observatories Origins Deep Survey-Herschel. We compare our predictions for differential galaxy number counts in the Herschel Photodetector Array Camera and Spectrometer (PACS) (100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE) (250, 350 and 500 μm) bands with available observations. We find very good agreement with the counts in the PACS bands, for the overall counts and for galaxies binned by redshift at z < 2. At z > 2 our model underpredicts the number of bright galaxies in the PACS bands by a factor of 10. The agreement is much worse for all three SPIRE bands and becomes progressively worse with increasing wavelength. We discuss a number of possible reasons for these discrepancies and hypothesize that the effect of blending on the observational flux estimates is likely to be the dominant issue. We note that the PACS number counts are relatively robust to changes in the dust-emission templates, at least for the three sets of templates that we have tested, while the predicted SPIRE number counts are more template dependent especially at low redshift. We present quantitative predictions for the relationship between the observed PACS 160 and SPIRE 250 μm fluxes and physical quantities such as halo mass, stellar mass, cold gas mass, star formation rate and total infrared (IR) luminosity, at different redshifts. We also present predictions for the radial sizes of Herschel-selected discs at high redshift (z > 2) and find reasonable agreement with the available observations. Finally, we present quantitative predictions for the correlation between the PACS 160 μm flux and the probability that a galaxy has experienced a recent major or minor merger. Although our models predict a strong correlation between these quantities, such that more IR-luminous galaxies are more likely to be merger driven, we find that a significant fraction (more than half) of all high-redshift IR-luminous galaxies detected by Herschel are able to attain their high star formation rates without enhancement by a merger.
Arousal and awareness are two important components of consciousness states. Functional neuroimaging has furthered our understanding of cortical and thalamocortical mechanisms of awareness. ...Investigating the relationship between subcortical functional connectivity and arousal has been challenging owing to the relatively small size of brainstem structures and thalamic nuclei, and their depth in the brain.
Resting state functional MRI scans of 72 healthy volunteers were acquired before, during, 1 h after, and 1 day after sevoflurane general anaesthesia. Functional connectivity of subcortical regions of interest vs whole brain and homotopic functional connectivity for assessment of left–right symmetry analyses of both cortical and subcortical regions of interest were performed. Both analyses used high resolution atlases generated from deep brain stimulation applications.
Functional connectivity in subcortical loci within the thalamus and of the ascending reticular activating system was sharply restricted under anaesthesia, featuring a general lateralisation of connectivity. Similarly, left–right homology was sharply reduced under anaesthesia. Subcortical bilateral functional connectivity was not fully restored after emergence from anaesthesia, although greater restoration was seen between ascending reticular activating system loci and specific thalamic nuclei thought to be involved in promoting and maintaining arousal. Functional connectivity was fully restored to baseline by the following day.
Functional connectivity in the subcortex is sharply restricted and lateralised under general anaesthesia. This restriction may play a part in loss and return of consciousness.
NCT02275026.
We present a lens model for the cluster SPT-CLJ0615−5746, which is the highest-redshift (z = 0.972) system in the Reionization of Lensing Clusters Survey, making it the highest-redshift cluster for ...which a full, strong lens model is published. We identify three systems of multiply imaged lensed galaxies, two of which we spectroscopically confirm at z = 1.358 and z = 4.013, which we use as constraints for the model. We find a foreground structure at z ∼ 0.4, which we include as a second cluster-sized halo in one of our models; however, two different statistical tests find the best-fit model consists of one cluster-sized halo combined with three individually optimized galaxy-sized halos, as well as contributions from the cluster galaxies themselves. We find the total projected mass density within r = 26 7 (the region where the strong lensing constraints exist) to be M☉. If we extrapolate out to r500, our projected mass density is consistent with the mass inferred from weak lensing and from the Sunyaev-Zel'dovich effect (M ∼ 1015 M☉). This cluster is lensing a previously reported z ∼ 10 galaxy, which, if spectroscopically confirmed, will be the highest-redshift strongly lensed galaxy known.
In this paper, a whole frame loss error concealment algorithm for three-dimensional video coding is proposed. The main concept of the proposed algorithm is to extrapolate the motion vectors for ...concealing a current error block by jointly considering the available motion vector and the depth information. In addition, the depth information is adopted to help the derivation of reference pixels for concealing errors in the case that suitable motion vectors cannot be obtained by the motion vector extrapolation process alone. Simulation results demonstrate that our proposed algorithm can achieve up to 0.52 dB PSNR, as well as subjective quality improvement, compared to previous work.
Extensive surveys with the Hubble Space Telescope over the past decade, targeting some of the most massive clusters in the sky, have uncovered dozens of galaxy cluster strong lenses. The massive ...cluster strong-lens scale is typically θE ∼ 10″ to ∼30″-35″, with only a handful of clusters known with Einstein radii θE ∼ 40″ or above (for zsource = 2, nominally). Here we report another very large cluster lens, RXC J0032.1+1808 (z = 0.3956), the second-richest cluster in the redMapper cluster catalog and the 85th most massive cluster in the Planck Sunyaev-Zel'dovich catalog. With our light-traces-mass and fully parametric approaches, we construct strong-lensing models based on 18 multiple images of five background galaxies newly identified in the Hubble data, mainly from the Reionization Lensing Cluster Survey (RELICS), in addition to a known sextuply imaged system in this cluster. Furthermore, we compare these models to Lenstool and GLAFIC models that were produced independently as part of the RELICS program. All models reveal a large effective Einstein radius of θE 40″ (zsource = 2), owing to the obvious concentration of substructures near the cluster center. Although RXC J0032.1+1808 has a very large critical area and high lensing strength, only three magnified high-redshift candidates are found within the field targeted by RELICS. Nevertheless, we expect many more high-redshift candidates will be seen in wider and deeper observations with Hubble or the James Webb Space Telescope. Finally, the comparison between several algorithms demonstrates that the total error budget is largely dominated by systematic uncertainties.
Seven-Tesla (7T) magnetic resonance imaging (MRI) has demonstrated value for evaluating a variety of intracranial diseases. However, its utility in trigeminal neuralgia has received limited ...attention. The authors of the present study applied ultra-high field multimodal MRI to two representative patients with secondary trigeminal neuralgia due to epidermoid tumors to illustrate the possible clinical and surgical advantages of 7T compared with standard clinical strength imaging. Techniques included co-registration of multiple 7T sequences to optimize the detection of potential concurrent neurovascular and neoplasm-derived compression.
7T MRI studies were performed using a whole body scanner. Two- and three-dimensional renderings of potential neurovascular conflict were created by co-registering time-of-flight angiography and T2-weighted turbo spin echo images in MATLAB and GE software. Detailed comparisons of the various field strength images were provided by a collaborating neuroradiologist (B.D.).
7T MRI clearly illustrated minute tumor-adjacent vasculature. In contrast, conventional, low-field imaging did not consistently provide adequate details to distinguish cerebrospinal fluid pulsatility from vessels. The tumor margins, although distinct from the trigeminal nerve fibers at 7T, blended with those of the surrounding structures at 3T. Two- and three-dimensional co-registration of time-of-flight angiography with T2-weighted MRI suggested that delicate, intervening vasculature may have contributed to these illustrative patients' symptomatology.
7T provided superior visualization of vital landmarks and subtle nerve and vessel features. Co-registration of various advanced 7T modalities may help to resolve complex disease etiologies. Future studies should explore the extent to which this dual etiology might persist across tumor types and utilize diffusion-based techniques to quantify what microstructural differences might exist between patients with trigeminal neuralgia from varying etiologies.
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