Multi-object spectroscopy of the field surrounding PKS 2126-158: Discovery of a z=0.66 galaxy group

The high-redshift radio-loud quasar PKS 2126-158 is found to have a large number of red galaxies in close apparent proximity. We use the Gemini Multi-Object Spectrograph (GMOS) on Gemini South to obtain optical spectra for a large fraction of these sources. We show that there is a group of galaxies at $z\sim0.66$, coincident with a metal-line absorption system seen in the quasar's optical spectrum. The multiplexing capabilities of GMOS also allow us to measure redshifts of many foreground galaxies in the field surrounding the quasar. The galaxy group has five confirmed members, and a further four fainter galaxies are possibly associated. All confirmed members exhibit early-type galaxy spectra, a rare situation for a Mg II absorbing system. We discuss the relationship of this group to the absorbing gas, and the possibility of gravitational lensing of the quasar due to the intervening galaxies.Comment: Monthly Notices of the Royal Astronomical Society, in press. 10 pages, 8 figure

Working memory in schizophrenics and older adults : a mediator for episodic memory deficits?

The purpose of this study was to determine the role of working memory on episodic memory in older adults and adults with schizophrenia. This study included 15 adults with schizophrenia, 20 young adults without psychopathology, and 21 older adults without psychopathology. Storage working memory scores were greater than processing working memory scores in all groups. Young adults had the fewest problems with episodic and working memory, compared to older adults and adults with schizophrenia, who had similar deficits in both memory types. Speed of processing was found to be the greatest predictor of working memory capacity

Monotonic and Cyclic Compression Behavior of Bulk Metallic Glasses

The cyclic-compression behavior of a Cu45Zr45Al5Ag5 bulk metallic glass (BMG) was investigated in order to elucidate the damage initiation and growth mechanisms. The present Cu45Zr45Al5Ag5 BMG was found to have the highest fatigue-endurance limit for BMGs reported to date. Fracture under cyclic compression occurred in a pure shear mode. In addition to many shear bands and cracks, areas of “chipping” were commonly found on the outside surfaces of the fatigue specimens. Crack growth rates were found decrease with cycles. The effects of the as-cast specimen size, cooling rate, and the free volume content on the monotonic and cyclic compression behavior of a Zr-based BMG was investigated. The smaller samples experienced a faster cooling rate, resulting in a higher free volume content. The smaller samples displayed superior monotonic compression and cyclic compression properties. This trend was attributed to a higher free volume content. The effect of the sample aspect ratio (height/diameter) on the cyclic compression behavior of a Zr-based BMG was explored. For smaller aspect ratios (0.5), the yield strength and compressive plastic strain significantly increased when compared to that for an aspect ratio of 2. In general, when the aspect ratio was 0.5, the fatigue lives were longer than when the aspect ratio was 2. The dramatic effect of the sample aspect ratio was attributed to the development of a hydrostatic stress state from the interaction of the uniaxial applied load and the friction stress developed at the interface of the top and bottom specimen surfaces and the platens. The stress-life fatigue behavior and fracture morphology of a (Cu60Zr30Ti10)99Sn1 BMG alloy was investigated under both 3-point and 4-point bending conditions. For all stress levels tested, the fatigue lifetimes tended to be higher for the 3-point loading condition. All fracture surfaces were found to be comprised of four main regions: a crack-initiation site, a stable crack-growth region, an unstable fast-fracture region, and a melting region. Finely spaced parallel marks oriented somewhat perpendicular to the direction of crack propagation were observed in the stable crack-growth region. Analyses of these marks found that their spacing increased with increasing stress intensity- factor range

Why concert promoters matter

Forming a companion piece to Frith’s 2007 article on why live music matters, this paper argues that there is a need to refine accounts of the music industries to reflect live music’s growing dominance. It does so by focusing on the rock/pop concert promoter and posits that in contrast to traditional definitions, the role of the promoter is astonishingly flexible and adaptable. The authors argue that the promoter necessarily ‘wears many hats’ and offer three promotional models to understand the work that promoters do. To illustrate this and to understand the development of live music promotion in the UK from 1955 onwards, the article compares and contrasts historical research with contemporary ethnography

Technical Note: Durability Analysis of Large Corn Stover Briquettes

Densification of agricultural residues is a key step in a cost-effective, large-scale, biomass feedstock supply system. Lab-scale densification systems exist which can produce large-scale densified corn stover briquettes that measure between 220 and 420 mm in length and with an average bulk density of 190 kg/m3 (dry particle density of 460 kg/m3). MOG (material other than grain ) and pure cob briquettes produced similar lengths and dry particle densities of 424 kg/m3 and 421 kg/m3, respectively. Durability testing, utilizing a modified form of ASABE S269.4 (ASABE Standards, 2007) was conducted to determine the overall product quality associated with these densified briquettes. This publication describes experiments which quantified the durability or briquettes produced with different material types (corn stover, MOG, the chaff from a conventional corn harvest, and pure cobs) and material particle sizes (produced from a combine chopper, MOG, and a hammer mill with a 19-mm screen opening size). The durability rating varied with each of the main effect test parameters and produced a maximum 46% durability rating using pure cobs directly from a combine without additional size reduction. The durability rating was quite low for corn stover and MOG briquettes, and it was improved for pure cob briquettes. Biomass preprocessing in a hammermill significantly reduced durability due to a lack of fiber interaction throughout the large briquette

Single-pass baling productivity and grain logistics analysis

Corn stover harvest in Iowa was studied using a single-pass combine and baler configuration over the last three years. The combine experienced a productivity loss from pulling a baler through the field of 6-10% depending on field conditions and speed. The additional biomass harvested by the combine lowered productivity depending upon the harvest rate and yield of the biomass. At the 1.4 ton rate in 2011 fall harvest the average maximum productivity loss was 25-30%. The loss was experienced in experiments without factoring in grain logistics. A model was developed to look at the field logistics of the grain cart to and from a single-pass combine when unloading on the go. The model showed that only a 16% loss in actual productivity when compared to a conventional combine which unloaded on the go as well

Corn Stover Densification Methods and their Large-Scale Logistical Impacts—Preliminary Analysis

The bulk density of corn stover poses a major obstruction to its large scale acceptance as a biomass feedstock. The loose bulk density of corn stover is low enough to create large inefficiencies during the harvest, transport, and storage phases of production. Overall production costs of stover could be reduced if a densification method were developed that provided adequate bulk density at a low specific energy during the harvest phase of production. So far, stover densification has been accomplished either by baling, grinding, or briquetting processes. Baling faces a logistical challenge with the handling cost of an individual bale, grinding systems don’t achieve high enough bulk densities alone, and briquetting systems generally require stover preprocessing (grinding), and the addition of heat energy. All of these factors for each system drive up the unit cost of corn stover production

Microlensing Constraints on Broad Absorption and Emission Line Flows in the Quasar H1413+117

We present new integral field spectroscopy of the gravitationally lensed broad absorption line (BAL) quasar H1413+117, covering the ultraviolet to visible rest-frame spectral range. We observe strong microlensing signatures in lensed image D, and we use this microlensing to simultaneously constrain both the broad emission and broad absorption line gas. By modeling the lens system over the range of probable lensing galaxy redshifts and using on a new argument based on the wavelength-independence of the broad line lensing magnifications, we determine that there is no significant broad line emission from smaller than ~20 light days. We also perform spectral decomposition to derive the intrinsic broad emission line (BEL) and continuum spectrum, subject to BAL absorption. We also reconstruct the intrinsic BAL absorption profile, whose features allow us to constrain outflow kinematics in the context of a disk-wind model. We find a very sharp, blueshifted onset of absorption of 1,500 km/s in both C IV and N V that may correspond to an inner edge of a disk-wind's radial outflow. The lower ionization Si IV and Al III have higher-velocity absorption onsets, consistent with a decreasing ionization parameter with radius in an accelerating outflow. There is evidence of strong absorption in the BEL component which indicates a high covering factor for absorption over two orders of magnitude in outflow radius.Comment: 29 pages, 8 figure

Self-Supervised Blind Source Separation via Multi-Encoder Autoencoders

The task of blind source separation (BSS) involves separating sources from a mixture without prior knowledge of the sources or the mixing system. This is a challenging problem that often requires making restrictive assumptions about both the mixing system and the sources. In this paper, we propose a novel method for addressing BSS of non-linear mixtures by leveraging the natural feature subspace specialization ability of multi-encoder autoencoders with fully self-supervised learning without strong priors. During the training phase, our method unmixes the input into the separate encoding spaces of the multi-encoder network and then remixes these representations within the decoder for a reconstruction of the input. Then to perform source inference, we introduce a novel encoding masking technique whereby masking out all but one of the encodings enables the decoder to estimate a source signal. To this end, we also introduce a so-called pathway separation loss that encourages sparsity between the unmixed encoding spaces throughout the decoder's layers and a so-called zero reconstruction loss on the decoder for coherent source estimations. In order to carefully evaluate our method, we conduct experiments on a toy dataset and with real-world biosignal recordings from a polysomnography sleep study for extracting respiration.Comment: 17 pages, 8 figures, submitted to Information Science