ALBERT

Description: The objective of this study was to compare the utility of combinations of data from airborne laser scanning (ALS), RapidEye satellite imagery and auxiliary environmental data to predict stand structure in a plantation forest. Both parametric and non-parametric modelling techniques that could simultaneously predict a multivariate response were employed and found to produce predictions with similar levels of accuracy. Response variables were derived from 463 field measurement plots that were used during model development; a further 60 randomly selected plots were set aside for validation of model performance. Candidate predictor variables were extracted from the ALS data, satellite data and auxiliary environmental data, and the variables with the greatest explanatory power were used to create six separate models based on combinations of the data sources. Model validation showed that models using RapidEye data only were the least precise and that adding auxiliary environmental data only led to a moderate improvement in model precision. The model precision observed was similar to those reported previously from studies using satellite data to predict stand structure. Models developed using data from ALS were by far the most precise and adding information from satellite data or auxiliary environmental data led to negligible improvement in the prediction of stand structure. Although the outputs of both model types were similar, the practical efficiencies of using the non-parametric approach make it appealing to meet the demands of managers of industrial plantation forest managers.

Description: ‘Perytons’ are millisecond-duration transients of terrestrial origin, whose frequency-swept emission mimics the dispersion of an astrophysical pulse that has propagated through tenuous cold plasma. In fact, their similarity to FRB 010724 had previously cast a shadow over the interpretation of ‘fast radio bursts’ (FRBs), which otherwise appear to be of extragalactic origin. Until now, the physical origin of the dispersion-mimicking perytons had remained a mystery. We have identified strong out-of-band emission at 2.3–2.5 GHz associated with several peryton events. Subsequent tests revealed that a peryton can be generated at 1.4 GHz when a microwave oven door is opened prematurely and the telescope is at an appropriate relative angle. Radio emission escaping from microwave ovens during the magnetron shut-down phase neatly explains all of the observed properties of the peryton signals. Now that the peryton source has been identified, we furthermore demonstrate that the microwave ovens on site could not have caused FRB 010724. This and other distinct observational differences show that FRBs are excellent candidates for genuine extragalactic transients.

Description: In recent years, millisecond-duration radio signals originating in distant galaxies appear to have been discovered in the so-called fast radio bursts. These signals are dispersed according to a precise physical law and this dispersion is a key observable quantity, which, in tandem with a redshift measurement, can be used for fundamental physical investigations. Every fast radio burst has a dispersion measurement, but none before now have had a redshift measurement, because of the difficulty in pinpointing their celestial coordinates. Here we report the discovery of a fast radio burst and the identification of a fading radio transient lasting ~6 days after the event, which we use to identify the host galaxy; we measure the galaxy's redshift to be z = 0.492 +/- 0.008. The dispersion measure and redshift, in combination, provide a direct measurement of the cosmic density of ionized baryons in the intergalactic medium of OmegaIGM = 4.9 +/- 1.3 per cent, in agreement with the expectation from the Wilkinson Microwave Anisotropy Probe, and including all of the so-called 'missing baryons'. The ~6-day radio transient is largely consistent with the radio afterglow of a short gamma-ray burst, and its existence and timescale do not support progenitor models such as giant pulses from pulsars, and supernovae. This contrasts with the interpretation of another recently discovered fast radio burst, suggesting that there are at least two classes of bursts.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Keane, E F -- Johnston, S -- Bhandari, S -- Barr, E -- Bhat, N D R -- Burgay, M -- Caleb, M -- Flynn, C -- Jameson, A -- Kramer, M -- Petroff, E -- Possenti, A -- van Straten, W -- Bailes, M -- Burke-Spolaor, S -- Eatough, R P -- Stappers, B W -- Totani, T -- Honma, M -- Furusawa, H -- Hattori, T -- Morokuma, T -- Niino, Y -- Sugai, H -- Terai, T -- Tominaga, N -- Yamasaki, S -- Yasuda, N -- Allen, R -- Cooke, J -- Jencson, J -- Kasliwal, M M -- Kaplan, D L -- Tingay, S J -- Williams, A -- Wayth, R -- Chandra, P -- Perrodin, D -- Berezina, M -- Mickaliger, M -- Bassa, C -- England -- Nature. 2016 Feb 25;530(7591):453-6. doi: 10.1038/nature17140.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Square Kilometre Array Organisation, Jodrell Bank Observatory, SK11 9DL, UK. ; Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Mail H29, PO Box 218, Victoria 3122, Australia. ; Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), Australia. ; Commonwealth Science and Industrial Research Organisation (CSIRO), Astronomy and Space Science, Australia Telescope National Facility, PO Box 76, Epping, New South Wales 1710, Australia. ; International Centre for Radio Astronomy Research, Curtin University, Bentley, Western Australia 6102, Australia. ; Instituto Nazionale di Astrofisica (INAF)-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (CA), Italy. ; Research School of Astronomy and Astrophysics, Australian National University, Canberra, Australian Capital Territory 2611, Australia. ; Max-Planck-Institut fur Radioastronomie (MPIfR), Auf dem Hugel 69, D-53121 Bonn, Germany. ; Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK. ; National Radio Astronomy Observatory, Socorro, New Mexico, USA. ; Department of Astronomy, the University of Tokyo, Hongo, Tokyo 113-0033, Japan. ; National Astronomical Observatory of Japan, 2 Chome-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan. ; Department of Astronomical Science, SOKENDAI (Graduate University for the Advanced Study), Osawa, Mitaka 181-8588, Japan. ; Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, Hawaii 96720, USA. ; Institute of Astronomy, Graduate School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan. ; Kavli Institute for the Physics and Mathematics of the Universe (WPI), Institutes for Advanced Study, University of Tokyo, Kashiwa, Chiba 277-8583, Japan. ; Department of Physics, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Kobe, Hyogo 658-8501, Japan. ; Cahill Center for Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA. ; Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA. ; National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus, Ganeshkhind, Pune 411 007, India. ; ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, NL-7990 AA Dwingeloo, The Netherlands.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26911781" target="_blank"〉PubMed〈/a〉

Description: Switchgrass ( Panicum virgatum L.) is a C4 grass with high biomass yield potential and is now a model species for the Bioenergy Feedstock Development Program. Two distinct ecotypes (e.g., upland and lowland) and a range of plant morphotypes (e.g., leafy and stemmy) have been observed in switchgrass. The objective of this study was to determine the influence of ecotype and morphotype on biomass feedstock quality. Leaf and stem tissues of leafy and stemmy morphotypes from both lowland and upland ecotypes were analyzed for key feedstock traits. The leaf : stem ratio of leafy morphotype was more than 40% higher than the stemmy morphotype in both upland and lowland ecotypes. Therefore, the stemmy morphotype has significant advantages over leafy morphotype during harvesting, storage, transportation and finally the feedstock quality. Remarkable differences in feedstock quality and mineral composition were observed in switchgrass genotypes with distinct ecotypic origins and variable plant morphotypes. Lignin, hemicelluloses and cellulose concentrations were higher in stems than in the leaves, while ash content was notably high in leaves. A higher concentration of potassium was found in the stems compared to the leaves. In contrast, calcium was higher and magnesium was generally higher in the leaves compared to stems. The upland genotypes demonstrated considerably higher lignin (14.4%) compared with lowland genotypes (12.4%), while hemicellulose was higher in lowland compared with upland. The stemmy type demonstrated slightly higher lignin compared with leafy types ( P  〈 0.1). Differences between the ecotypes and morphotypes for key quality traits demonstrated the potential for improving feedstock composition of switchgrass through selection in breeding programs.

Description: Author(s): Susheel S. Bhandari, K. Muralidhar, and Yogesh M. Joshi We study the diffusion of heat in an aqueous suspension of disk-shaped nanoparticles of Laponite, which has finite elasticity and a pastelike consistency, by using the Mach-Zehnder interferometer. We estimate the thermal diffusivity of the suspension by comparing the experimentally obtained temperat... [Phys. Rev. E 87, 022301] Published Mon Feb 04, 2013