Abstract
We present cosmological parameter constraints from a joint analysis of three cosmological probes: the tomographic cosmic shear signal in ∼450 deg2 of data from the Kilo Degree Survey (KiDS), ...the galaxy-matter cross-correlation signal of galaxies from the Galaxies And Mass Assembly (GAMA) survey determined with KiDS weak lensing, and the angular correlation function of the same GAMA galaxies. We use fast power spectrum estimators that are based on simple integrals over the real-space correlation functions, and show that they are practically unbiased over relevant angular frequency ranges. We test our full pipeline on numerical simulations that are tailored to KiDS and retrieve the input cosmology. By fitting different combinations of power spectra, we demonstrate that the three probes are internally consistent. For all probes combined, we obtain $S_8\equiv \sigma _8 \sqrt{\Omega _{\rm m}/0.3}=0.800_{-0.027}^{+0.029}$, consistent with Planck and the fiducial KiDS-450 cosmic shear correlation function results. Marginalizing over wide priors on the mean of the tomographic redshift distributions yields consistent results for S8 with an increase of $28\, {per \,cent}$ in the error. The combination of probes results in a 26 per cent reduction in uncertainties of S8 over using the cosmic shear power spectra alone. The main gain from these additional probes comes through their constraining power on nuisance parameters, such as the galaxy intrinsic alignment amplitude or potential shifts in the redshift distributions, which are up to a factor of 2 better constrained compared to using cosmic shear alone, demonstrating the value of large-scale structure probe combination.
Abstract
We study the statistics of peaks in a weak-lensing reconstructed mass map of the first 450 deg2 of the Kilo Degree Survey (KiDS-450). The map is computed with aperture masses directly ...applied to the shear field with an NFW-like compensated filter. We compare the peak statistics in the observations with that of simulations for various cosmologies to constrain the cosmological parameter $S_8 = \sigma _8 \sqrt{\Omega _{\rm m}/0.3}$, which probes the (Ωm, σ8) plane perpendicularly to its main degeneracy. We estimate S8 = 0.750 ± 0.059, using peaks in the signal-to-noise range 0 ≤ S/N ≤ 4, and accounting for various systematics, such as multiplicative shear bias, mean redshift bias, baryon feedback, intrinsic alignment, and shear–position coupling. These constraints are ∼ 25 per cent tighter than the constraints from the high significance peaks alone (3 ≤ S/N ≤ 4) which typically trace single-massive haloes. This demonstrates the gain of information from low-S/N peaks. However, we find that including S/N < 0 peaks does not add further information. Our results are in good agreement with the tomographic shear two-point correlation function measurement in KiDS-450. Combining shear peaks with non-tomographic measurements of the shear two-point correlation functions yields a ∼20 per cent improvement in the uncertainty on S8 compared to the shear two-point correlation functions alone, highlighting the great potential of peaks as a cosmological probe.
The unknown nature of ‘dark energy’ motivates continued cosmological tests of large-scale gravitational physics. We present a new consistency check based on the relative amplitude of non-relativistic ...galaxy peculiar motions, measured via redshift-space distortion, and the relativistic deflection of light by those same galaxies traced by galaxy–galaxy lensing. We take advantage of the latest generation of deep, overlapping imaging and spectroscopic data sets, combining the Red Cluster Sequence Lensing Survey, the Canada–France–Hawaii Telescope Lensing Survey, the WiggleZ Dark Energy Survey and the Baryon Oscillation Spectroscopic Survey. We quantify the results using the ‘gravitational slip’ statistic E
G, which we estimate as 0.48 ± 0.10 at z = 0.32 and 0.30 ± 0.07 at z = 0.57, the latter constituting the highest redshift at which this quantity has been determined. These measurements are consistent with the predictions of General Relativity, for a perturbed Friedmann–Robertson–Walker metric in a Universe dominated by a cosmological constant, which are E
G = 0.41 and 0.36 at these respective redshifts. The combination of redshift-space distortion and gravitational lensing data from current and future galaxy surveys will offer increasingly stringent tests of fundamental cosmology.
The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with a goal of testing and facilitating the development of methods for analyzing ...astronomical images that will be used to measure weak gravitational lensing. This measurement requires extremely precise estimation of very small galaxy shape distortions, in the presence of far larger intrinsic galaxy shapes and distortions due to the blurring kernel caused by the atmosphere, telescope optics, and instrumental effects. Uie GREAT3 challenge is posed to the astronomy, machine learning, and statistics communities, and includes tests of three specific effects that are of immediate relevance to upcoming weak lensing surveys, two of which have never been tested in a community challenge before. These effects include many novel aspects including realistically complex galaxy models based on high-resolution imaging from space; a spatially varying, physically motivated blurring kernel; and a combination of multiple different exposures. To facilitate entry by people new to the field, and for use as a diagnostic tool, the simulation software for the challenge is publicly available, though the exact parameters used for the challenge are blinded. Sample scripts to analyze the challenge data using existing methods will also be provided. See http://great3challenge.info and http://great3.projects.phys.ucl.ac.uk/leaderboard/ for more information.
Objectives
We studied the usefulness of early dynamic (ED) and whole-body (WB) FDG-PET/CT for the evaluation of renal cell carcinoma (RCC).
Methods
One hundred patients with 107 tumours underwent ...kidney ED and WB FDG-PET/CT. We visually and semiquantitatively evaluated the FDG accumulation in RCCs in the ED and WB phases, and compared the accumulation values with regard to histological type (clear cell carcinoma CCC vs. non-clear cell carcinoma N-CCC), the TNM stage (high stage 3–4 vs. low stage 1–2), the Fuhrman grade (high grade 3–4 vs. low grade 1–2) and presence versus absence of venous (V) and lymphatic (Ly) invasion.
Results
In the ED phase, visual evaluation revealed no significant differences in FDG accumulation in terms of each item. However, the maximum standardized uptake value and tumour-to-normal tissue ratios were significantly higher in the CCCs compared to the N-CCCs (
p
< 0.001). In the WB phase, in contrast, significantly higher FDG accumulation (
p
< 0.001) was found in RCCs with a higher TNM stage, higher Furman grade, and the presence of V and Ly invasion in both the visual and the semiquantitative evaluations.
Conclusions
ED and WB FDG-PET/CT is a useful tool for the evaluation of RCCs.
Key Points
• ED and WB FDG-PET/ CT helps to assess patients with RCC
• ED FDG-PET/CT enabled differentiation between CCC and N-CCC
• FDG accumulation in the WB phase reflects tumour aggressiveness
• Management of RCC is improved by ED and WB FDG-PET/CT
Abstract
We constrain the average halo ellipticity of ∼2600 galaxy groups from the Galaxy And Mass Assembly (GAMA) survey, using the weak gravitational lensing signal measured from the overlapping ...Kilo Degree Survey (KiDS). To do so, we quantify the azimuthal dependence of the stacked lensing signal around seven different proxies for the orientation of the dark matter distribution, as it is a priori unknown which one traces the orientation best. On small scales, the major axis of the brightest group/cluster member (BCG) provides the best proxy, leading to a clear detection of an anisotropic signal. In order to relate that to a halo ellipticity, we have to adopt a model density profile. We derive new expressions for the quadrupole moments of the shear field given an elliptical model surface mass density profile. Modelling the signal with an elliptical Navarro–Frenk–White profile on scales R < 250 kpc, and assuming that the BCG is perfectly aligned with the dark matter, we find an average halo ellipticity of εh = 0.38 ± 0.12, in fair agreement with results from cold dark matter only simulations. On larger scales, the lensing signal around the BCGs becomes isotropic and the distribution of group satellites provides a better proxy for the halo's orientation instead, leading to a 3σ–4σ detection of a non-zero halo ellipticity at 250 < R < 750 kpc. Our results suggest that the distribution of stars enclosed within a certain radius forms a good proxy for the orientation of the dark matter within that radius, which has also been observed in hydrodynamical simulations.
We investigated the role of F-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) for the differential diagnosis of malignant and benign pleural effusion. We ...studied 36 consecutive patients with histologically proven cancer (excluding malignant mesothelioma) who underwent FDG-PET/CT for suspected malignant pleural effusion. Fourteen patients had cytologically proven malignant pleural effusion and the other 22 patients had either negative cytology or clinical follow-up, which confirmed the benign etiology. We examined the maximum standardized uptake values (SUV max) of pleural effusion and the target-to-normal tissue ratio (TNR), calculated as the ratio of the pleural effusion SUV max to the SUV mean of the normal tissues (liver, spleen, 12th thoracic vertebrae Th12, thoracic aorta, and spinalis muscle). We also examined the size and density (in Hounsfield units) of the pleural effusion and pleural abnormalities on CT images. TNR (Th12) and increased pleural FDG uptake compared to background blood pool were significantly more frequent in cases with malignant pleural effusion (P < 0.05 for both). The cutoff TNR (Th12) value of >0.95 was the most accurate; the sensitivity, specificity, and accuracy for this value were 93%, 68%, and 75%, respectively. FDG-PET/CT can be a useful method for the differential diagnosis of malignant and benign pleural effusion.
Alumina nanoparticles (NPs) were synthesized by laser ablation of a bulk α-alumina (corundum) target immersed in distilled water using nanosecond laser pulses of 1064-nm wavelength. We investigated ...the effect of laser power and water column above the target. Synthesized particles were analyzed regarding particle shape and size distributions with scanning electron and transmission electron microscopy. Ablated NPs were spherical in shape and the average particle size ranged from 12 to 18nm at varied laser power and water levels, although a very small number of melted droplets of submicron spheroids and irregular-shaped cracked particles were observed. X-ray diffraction analysis was conducted, which shows mainly the peaks of α-Al2O3 and minor peaks of γ-Al2O3. Phase identification of NPs, using high-resolution transmission electron micrograph lattice images and fast Fourier transform exhibits both metastable γ-Al2O3 and stable α-Al2O3 phases.
PDF
