Swinburne University of Technology

About: Swinburne University of Technology is a education organization based out in Melbourne, Victoria, Australia. It is known for research contribution in the topics: Galaxy & Population. The organization has 7223 authors who have published 25530 publications receiving 667955 citations. The organization is also known as: Swinburne Technical College & Swinburne College of Technology.

On a wave-induced turbulence and a wave-mixed upper ocean layer

Abstract: [1] A concept of wave-amplitude-based Reynolds number is suggested which is hypothesised to indicate a transition from laminarity to turbulence for the wave-induced motion If the hypothesis is correct, the wave-induced motion can be turbulent and the depth of upper ocean mixing due to such wave-generated turbulence can be predicted based on knowledge of the wave climate Estimates of the critical wave Reynolds number provide an approximate value of Recr = 3000 This number was tested on mechanically-generated laboratory waves and was confirmed Once this number is used for ocean conditions when mixing due to heating and cooling is less important than that due to the waves, quantitative and qualitative characteristics of the ocean's Mixed Layer Depth (MLD) are shown to be predicted with a satisfactory degree of agreement with observations Testing the hypothesis against other known results in turbulence generation and wave attenuation is also conducted

Highest-frequency detection of FRB 121102 at 4-8 GHz using the Breakthrough Listen Digital Backend at the Green Bank Telescope

Abstract: We report the first detections of the repeating fast radio burst source FRB 121102 above 5.2 GHz. Observations were performed using the 4$-$8 GHz receiver of the Robert C. Byrd Green Bank Telescope with the Breakthrough Listen digital backend. We present the spectral, temporal and polarization properties of 21 bursts detected within the first 60 minutes of a total 6-hour observations. These observations comprise the highest burst density yet reported in the literature, with 18 bursts being detected in the first 30 minutes. A few bursts clearly show temporal sub-structures with distinct spectral properties. These sub-structures superimpose to provide enhanced peak signal-to-noise ratio at higher trial dispersion measures. Broad features occur in $\sim 1$ GHz wide subbands that typically differ in peak frequency between bursts within the band. Finer-scale structures ($\sim 10-50$ MHz) within these bursts are consistent with that expected from Galactic diffractive interstellar scintillation. The bursts exhibit nearly 100% linear polarization, and a large average rotation measure of 9.359$\pm$0.012 $\times$ 10$^{\rm 4}$ rad m$^{\rm -2}$ (in the observer's frame). No circular polarization was found for any burst. We measure an approximately constant polarization position angle in the 13 brightest bursts. The peak flux densities of the reported bursts have average values (0.2$\pm$0.1 Jy), similar to those seen at lower frequencies ($<3$ GHz), while the average burst widths (0.64$\pm$0.46 ms) are relatively narrower.

Chronic MDMA (ecstasy) use, cognition and mood

Abstract: It has been suggested that 3,4-methylenedioxymethamphetamine (MDMA or ecstasy) causes damage to the serotonergic system, and that this damage results in cognitive and mood impairments. To examine the effect of chronic MDMA usage on a wide battery of cognitive tests and psychological abilities and processes. In the present study, the performance of 17 participants with a history of MDMA use was compared to the performance of 15 control subjects on a battery of neuropsychological tests. This battery included tests for depression, immediate word recall, delayed recall, attention and working memory. Results indicated that the MDMA group had significantly higher scores for depression than the control group, and displayed poorer delayed recall and verbal learning than controls after accounting statistically for the effects of cannabis and depression. These results suggest that MDMA users exhibit difficulties in coding information into long-term memory, display impaired verbal learning, are more easily distracted, and are less efficient at focusing attention on complex tasks.

Light-Induced Tuning and Reconfiguration of Nanophotonic Structures

Abstract: Interaction of light pulses of various durations and intensities with nanoscale photonic structures plays an important role in many applications of nanophotonics for high-density data storage, ultra-fast data processing, surface coloring and sensing. A design of optically tunable and reconfigurable structures made from different materials is based on many important physical effects and advances in material science, and it employs the resonant character of light interaction with nanostructures and strong field confinement at the nanoscale. Here we review the recent progress in physics of tunable and reconfigurable nanophotonic structures of different types. We start from low laser intensities that produce weak reversible changes in nanostructures, and then move to the discussion of non-reversible changes in photonic structures. We focus on three platforms based on metallic, dielectric and hybrid resonant photonic structures such as nanoantennas, nanoparticle oligomers and nanostructured metasurfaces. Main challenges and key advantages of each of the approaches focusing on applications in advanced photonic technologies are also discussed.

BREAKING THE LAW: THE M bh-M spheroid RELATIONS FOR CORE-SÉRSIC AND SÉRSIC GALAXIES

Abstract: The popular log-linear relation between supermassive black hole mass, M bh, and the dynamical mass of the host spheroid, M sph, is shown to require a significant correction. Core galaxies, typically with M bh 2 × 108 M ☉ and thought to be formed in dry merger events, are shown to be well described by a linear relation for which the median black hole mass is 0.36%—roughly double the old value of constancy. Of greater significance is that M bh∝M 2 sph among the (non-pseudobulge) lower-mass systems: specifically, log [M bh/M ☉] = (1.92 ± 0.38)log [M sph/7 × 1010 M ☉] + (8.38 ± 0.17). "Classical" spheroids hosting a 106 M ☉ black hole will have M bh/M sph ~ 0.025%. These new relations presented herein (1) bring consistency to the relation M bh∝σ5 and the fact that L∝σ x with exponents of 5 and 2 for bright (MB –20.5 mag) and faint spheroids, respectively, (2) mimic the non-(log-linear) behavior known to exist in the M bh-(Sersic n) diagram, (3) necessitate the existence of a previously overlooked M bh∝L 2.5 relation for Sersic (i.e., not core-Sersic) galaxies, and (4) resolve past conflicts (in mass prediction) with the M bh-σ relation at the low-mass end. Furthermore, the bent nature of the M bh-M sph relation reported here for "classical" spheroids will have a host of important implications that, while not addressed in this paper, relate to (1) galaxy/black hole formation theories, (2) searches for the fundamental, rather than secondary, black hole scaling relation, (3) black hole mass predictions in other galaxies, (4) alleged pseudobulge detections, (5) estimates of the black hole mass function and mass density based on luminosity functions, (6) predictions for space-based gravitational wave detections, (7) connections with nuclear star cluster scaling relations, (8) evolutionary studies over different cosmic epochs, (9) comparisons and calibrations matching inactive black hole masses with low-mass active galactic nucleus data, and more.