3,090 research outputs found
The beginnings of geography teaching and research in the University of Glasgow: the impact of J.W. Gregory
J.W. Gregory arrived in Glasgow from Melbourne in 1904 to take up the post of foundation Professor of Geology in the University of Glasgow. Soon after his arrival in Glasgow he began to push for the setting up of teaching in Geography in Glasgow, which came to pass in 1909 with the appointment of a Lecturer in Geography. This lecturer was based in the Department of Geology in the University's East Quad. Gregory's active promotion of Geography in the University was matched by his extensive writing in the area, in textbooks, journal articles and popular books. His prodigious output across a wide range of subject areas is variably accepted today, with much of his geomorphological work being judged as misguided to varying degrees. His 'social science' publications - in the areas of race, migration, colonisation and economic development of Africa and Australia - espouse a viewpoint that is unacceptable in the twenty-first century. Nonetheless, that viewpoint sits squarely within the social and economic traditions of Gregory's era, and he was clearly a key 'Establishment' figure in natural and social sciences research in the first half of the twentieth century. The establishment of Geography in the University of Glasgow remains enduring testimony of J.W. Gregory's energy, dedication and foresight
A new genus and species of armored scale insect (Hemiptera: Diaspididae) from Australia found in the historic Koebele Collection of the California Academy of Sciences
A new genus and species of armored scale insect (Hemiptera: Diaspididae), Protomorgania koebelei Dooley and Evans, is described and illustrated from specimens collected by Albert Koebele on Pittosporum sp. (Pittosporaceae) in Australia around the year 1900. A key to the genera of armored scale insects similar to Protomorgania and known to occur in Australia is provided
Cycad Aulacaspis Scale, a Newly Introduced Insect Pest in Indonesia
Cycad aulacaspis scale (Aulacaspis yasumatsui Takagi (Hemiptera: Diaspididae)) is native to Thailand and Vietnam. Since the early 1990s it has been spreading around the world due to the trade in cycad plants for ornamental use. Infestation by this scale can kill cycads in only a few months. Its accidental introduction to Florida endangered the ornamental cycad-growing industry; and in Guam and Taiwan, endemic cycads (Cycas micronesica and C. taitungensis, respectively) are currently threatened with extinction by cycad aulacaspis scale. In November 2011, an introduced scale was discovered damaging cycads in the Bogor Botanic Garden. Samples from Bogor were taken for identification of the scale, and the material was kept for some time to rear out any insect parasitoids that were present. Both the scale insects and parasitoids were prepared on microscope slides and studied microscopically for authoritative identification. The scale was confirmed as A. yasumatsui. The parasitoid Arrhenophagus chionaspidis Aurivillius (Hymenoptera: Encyrtidae) and the hyperparasitoid Signiphora bifasciata Ashmead (Hymenoptera: Signiphoridae) were identified from the samples. Unless immediate remedial measures are taken, several endemic species of cycad in Indonesia may be endangered by infestation by cycad aulacaspis scale
Electron Beam Induced Luminescence of SiO2 Optical Coatings
Optical coatings of disordered thin film SiO2/SiOx dielectric samples on reflective metal substrates exhibited cathodoluminescence under electron beam irradiation. Measurements of the absolute radiance and emission spectra as functions of incident electron energy, flux and power over a range of sample temperatures are reported. Radiance reached a saturation plateau at high incident electron power. Well below saturation radiance scaled with deposited power, that is linearly with incident power for lower-energy non-penetrating electrons and decreasing with increasing energy for penetrating radiation. Four bands were observed in spectral measurements from 300 nm to 1000 nm. Changes in peak intensity and shifts in peak energies as functions of temperature are described. The observations are explained in terms of a simple disordered band theory model and the transitions that take place between electrons in extended conduction states and localized trapped states associated with structural or compositional defects in the highly disordered insulating materials; this provides a fundamental basis for understanding the dependence of cathodoluminescence on irradiation time, incident flux and energy, and sample thickness and temperature
Exact braneworld cosmology induced from bulk black holes
We use a new, exact approach in calculating the energy density measured by an
observer living on a brane embedded in a charged black hole spacetime. We find
that the bulk Weyl tensor gives rise to non-linear terms in the energy density
and pressure in the FRW equations for the brane. Remarkably, these take exactly
the same form as the ``unconventional'' terms found in the cosmology of branes
embedded in pure AdS, with extra matter living on the brane. Black hole driven
cosmologies have the benefit that there is no ambiguity in splitting the
braneword energy momentum into tension and additional matter. We propose a new,
enlarged relationship between the two descriptions of braneworld cosmology. We
also study the exact thermodynamics of the field theory and present a
generalised Cardy-Verlinde formula in this set up.Comment: 17 pages, no figures; v3: Minor change, References added, Version to
appear in CQ
Universality of Performance Indicators based on Citation and Reference Counts
We find evidence for the universality of two relative bibliometric indicators
of the quality of individual scientific publications taken from different data
sets. One of these is a new index that considers both citation and reference
counts. We demonstrate this universality for relatively well cited publications
from a single institute, grouped by year of publication and by faculty or by
department. We show similar behaviour in publications submitted to the arXiv
e-print archive, grouped by year of submission and by sub-archive. We also find
that for reasonably well cited papers this distribution is well fitted by a
lognormal with a variance of around 1.3 which is consistent with the results of
Radicchi, Fortunato, and Castellano (2008). Our work demonstrates that
comparisons can be made between publications from different disciplines and
publication dates, regardless of their citation count and without expensive
access to the whole world-wide citation graph. Further, it shows that averages
of the logarithm of such relative bibliometric indices deal with the issue of
long tails and avoid the need for statistics based on lengthy ranking
procedures.Comment: 15 pages, 14 figures, 11 pages of supplementary material. Submitted
to Scientometric
Pulsating star research and the Gaia revolution
In this article we present an overview of the ESA Gaia mission and of the
unprecedented impact that Gaia will have on the field of variable star
research. We summarise the contents and impact of the first Gaia data release
on the description of variability phenomena, with particular emphasis on
pulsating star research. The Tycho-Gaia astrometric solution, although limited
to 2.1 million stars, has been used in many studies related to pulsating stars.
Furthermore a set of 3,194 Cepheids and RR Lyrae stars with their times series
have been released. Finally we present the plans for the ongoing study of
variable phenomena with Gaia and highlight some of the possible impacts of the
second data release on variable, and specifically, pulsating stars.Comment: 12 pages, 4 figures, proceedings for the 22nd Los Alamos Stellar
Pulsation Conference Series Meeting "Wide field variability surveys: a
21st-century perspective", held in San Pedro de Atacama, Chile, Nov. 28 -
Dec. 2, 201
Updated Parameters and a New Transmission Spectrum of HD 97658b
Recent years have seen increasing interest in the characterization of sub-Neptune-sized planets because of their prevalence in the Galaxy, contrasted with their absence in our solar system. HD 97658 is one of the brightest stars hosting a planet of this kind, and we present the transmission spectrum of this planet by combining four Hubble Space Telescope transits, 12 Spitzer/IRAC transits, and eight MOST transits of this system. Our transmission spectrum has a higher signal-to-noise ratio than those from previous works, and the result suggests that the slight increase in transit depth from wavelength 1.1–1.7 μm reported in previous works on the transmission spectrum of this planet is likely systematic. Nonetheless, our atmospheric modeling results are inconclusive, as no model provides an excellent match to our data. Nonetheless, we find that atmospheres with high C/O ratios (C/O ≳ 0.8) and metallicities of ≳100× solar metallicity are favored. We combine the mid-transit times from all of the new Spitzer and MOST observations and obtain an updated orbital period of P = 9.489295 ± 0.000005, with a best-fit transit time center at T₀ = 2456361.80690 ± 0.00038 (BJD). No transit timing variations are found in this system. We also present new measurements of the stellar rotation period (34 ± 2 days) and stellar activity cycle (9.6 yr) of the host star HD 97658. Finally, we calculate and rank the Transmission Spectroscopy Metric of all confirmed planets cooler than 1000 K and with sizes between 1 R⊕ and 4 R⊕. We find that at least a third of small planets cooler than 1000 K can be well characterized using James Webb Space Telescope, and of those, HD 97658b is ranked fifth, meaning that it remains a high-priority target for atmospheric characterization
Morphological changes in American kestrels (Falco sparverius) at continental migration sites
Many American kestrel (Falco sparverius) populations are declining across North America. Potential causes include mortality from reduction in food availability, a changing climate, habitat degradation, an increase in avian predators, disease, and toxins. We analyzed American kestrel count and banding data from seven raptor migration sites throughout North America with at least 20 years of migration data. We used count data to determine the year at which the kestrel population began a significant decline and then used banding records to determine whether body mass and wing chord declined after this point. We found reductions in kestrel body mass at three sites and reductions in kestrel wing chord at five sites. Our results indicate declines in body size at the majority of sites are consistent with the hypotheses that food availability, impacts of a changing climate, or predation risk may be contributing to population declines
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