Seasonal MLT-region nightglow intensities, temperatures, and emission heights at a Southern Hemisphere midlatitude site

We consider 5 years of spectrometer measurements of OH(6–2) and O2(0–1) airglow emission intensities and temperatures made near Adelaide, Australia (35° S, 138° E), between September 2001 and August 2006 and compare them with measurements of the same parameters from at the same site using an airglow imager, with the intensities of the OH(8–3) and O(1S) emissions made with a filter photometer, and with 2 years of Aura MLS (Microwave Limb Sounder) v3.3 temperatures and 4.5 years of TIMED SABER (Thermosphere Ionosphere Mesosphere Energetics and Dynamics Sounding of the Atmosphere using Broadband Emission Radiometry) v2.0 temperatures for the same site. We also consider whether we can recover the actual emission heights from the intercomparison of the ground-based and satellite observations. We find a significant improvement in the correlation between the spectrometer OH and SABER temperatures by interpolating the latter to constant density surfaces determined using a meteor radar.Iain M. Reid, Andrew J. Spargo, Jonathan M. Woithe, Andrew R. Klekociuk, Joel P. Younger and Gulamabas G. Sivje

Imaging of atmospheric gravity waves in the stratosphere and upper mesosphere using satellite and ground-based observations over Australia during the TWPICE campaign

Extent: 20p.During the Tropical Warm Pool International Cloud Experiment (TWPICE) an intense tropical low was situated between Darwin and Alice Springs, Australia. Observations made on 31 January 2006 by the Atmospheric Infrared Sounder instrument on the NASA Aqua satellite imaged the presence of atmospheric gravity waves (AGWs), at approximately 40 km altitude, with horizontal wavelengths between 200 and 400 km that were originating from the region of the storm. Airglow images obtained from Alice Springs (about 600 km from the center of the low) showed the presence of similar waves with observed periods of 1 to 2 h. The images also revealed the presence of 30- to 45-km-horizontal-wavelength AGWs with shorter observed periods of near 15 to 25 min. Ray tracing calculations show that (1) some of the long wavelength waves traveled on rays, without ducting, to the altitudes where the observations were obtained, and (2) shorter-period waves rapidly reached 85 km altitude at a horizontal distance close to the storm, thus occurring over Alice Springs only if they were trapped or ducted. The mesospheric inversion layer seen in the measured temperature data almost forms such a trapped region. The winds therefore critically control the formation of the trapped region. Wind profiles deduced from the available data show the plausibility for the formation of such a trapped region. Variations in the wind, however, would make ideal trapped region conditions short-lived, and this may account for the sporadic nature of the short-period wave observations.J. H. Hecht, M. J. Alexander, R. L. Walterscheid, L. J. Gelinas, R. A. Vincent, A. D. MacKinnon, J. M. Woithe, P. T. May, W. R. Skinner, M. G. Mlynczak, and J. M. Russell II

Observations of the phase-locked 2 day wave over the Australian sector using medium-frequency radar and airglow data

Extent: 22p.The quasi 2 day wave, with a nominal mean period just above 50 h, is a significant feature of the 80–100 km altitude region in both hemispheres. It becomes particularly prominent in the Southern Hemisphere summer at midlatitudes where, a short time after summer solstice, its amplitude rapidly increases and its mean period is found to be approximately 48 h, producing an oscillation phase locked in local time. This lasts for a few weeks. Presented here are observations of the meridional winds and airglow over two sites in Australia, for 4 years during the austral summers of 2003–2006. We show that during those times when the large-amplitude phase-locked 2 day wave (PL-TDW) is present the diurnal tide greatly decreases. This is consistent with the Walterscheid and Vincent (1996) model in which the PL-TDW derives its energy from a parametric excitation by the diurnal tide. These data also show that the diurnal tide is more suppressed and the PL-TDW amplitude is larger in odd-numbered years, suggesting a biannual effect. The airglow data indicated that, for the PL-TDW, the winds and temperature are nearly out of phase. When the PL-TDW is present airglow amplitudes can become quite large, a result dependent on the local time of the PL-TDW maximum. The airglow intensity response was, in general, much larger than what would be expected from the airglow temperature response, suggesting that the PL-TDW is causing a significant composition change possibly due to minor constituent transport.J. H. Hecht, R. L. Walterscheid, L. J. Gelinas, R. A. Vincent, I. M. Reid, and J. M. Woith

Chapter 19. In vitro studies of phenol coupling enzymes involved in vancomycin biosynthesis

Oxidative phenol cross-linking reactions play a key role in the biosynthesis of glycopeptide antibiotics such as vancomycin. The vancomycin aglycone contains three cross-links between aromatic amino acid side-chains, which stabilize the folded backbone conformation required for binding to the target D-Ala-D-Ala dipeptide. At least the first cross-link is introduced into a peptide precursor whilst it is still bound as a thioester to a peptide carrier protein (PCP) domain (also called a thiolation domain) within the nonribosomal peptide synthetase. We described here methods for the solid-phase synthesis of peptides and their coupling to PCP domains, which may be useful for in vitro studies of cross-linking and related tailoring reactions during nonribosomal glycopeptide antibiotic biosynthesis

What is your favourite particle and why?

We have conducted a large-scale international study with high-school teachers (N=530) and high-school students (N=959) from all around the world to investigate and document what they consider as their favourite particles. We found five particles to be highly prominent in both groups, namely the Higgs boson, the neutrino, the electron, the photon and the gluon. Moreover, we did not find any significant differences with regard to the teachers’ and students’ nationality or gender. In this article, we present our findings in detail and give insight into the teachers’ and students’ justifications of why they chose a specific particle.

What is your favourite particle and why?

Abstract We have conducted a large-scale international study with high-school teachers (N=530) and high-school students (N=959) from all around the world to investigate and document what they consider as their favourite particles. We found five particles to be highly prominent in both groups, namely the Higgs boson, the neutrino, the electron, the photon and the gluon. Moreover, we did not find any significant differences with regard to the teachers’ and students’ nationality or gender. In this article, we present our findings in detail and give insight into the teachers’ and students’ justifications of why they chose a specific particle.</jats:p

Bend it like dark matter!

Abstract Dark matter is one of the most intriguing scientific mysteries of our time and offers exciting instructional opportunities for physics education in high schools. The topic is likely to engage and motivate students in the classroom and allows addressing open questions of the Standard Model of particle physics. Although the empirical evidence of dark matter links nicely to many standard topics of physics curricula, teachers may find it challenging to introduce the topic in their classrooms. In this article, we present a fun new approach to teach about dark matter using jelly lenses as an instructional analogy of gravitational lenses. We provide a brief overview of the history of dark matter to contextualise our presentation and discuss the instructional potential as well as limitations of the jelly lens analogy.</jats:p

The variability of 558 nm OI nightglow intensity measured over Adelaide, Australia

Copyright © 2007 Published by Elsevier Ltd.The intensity of the OI 558 nm nightglow emission from heights near 97 km has been routinely measured since 1995 at Buckland Park (34.9°S, 138.6°E) near Adelaide, Australia. The intensity exhibits spring and autumn enhancements, bright nights and clear seasonal and inter-annual periodicities. Like many other mid-latitude observations, the autumn enhancement is greater than the spring enhancement. A Lomb periodogram analysis of the intensity indicates the presence of annual, semi-annual, and quasi-biennial oscillations. The annual and semi-annual oscillations have about equal intensity at this latitude, with amplitudes of between 17(±5)% and 14(±5)% of the mean intensity, respectively. This is consistent with Adelaide being a transitional latitude between a dominant semi-annual oscillation observed at low latitudes and the dominant annual oscillation observed at mid-latitudes. The annual oscillation is observed to peak in summer while the semi-annual oscillation takes maximum values near equinox. The quasi-biennial oscillation has a smaller amplitude at about 5(±1)% of the mean intensity and takes a maximum value near the autumnal equinox. There is evidence of a solar cycle dependence of the intensity, with nightglow intensity tracking the solar cycle. A harmonic fit to this period yields an amplitude of about 20(±15)% of the mean intensity, but naturally, this result needs to be treated with some caution, as there is only about one period present.http://www.elsevier.com/wps/find/journaldescription.cws_home/644/description#descriptio