19,033 research outputs found
Early Results from TUS, the First Orbital Detector of Extreme Energy Cosmic Rays
TUS is the world's first orbital detector of extreme energy cosmic rays
(EECRs), which operates as a part of the scientific payload of the Lomonosov
satellite since May 19, 2016. TUS employs the nocturnal atmosphere of the Earth
to register ultraviolet (UV) fluorescence and Cherenkov radiation from
extensive air showers generated by EECRs as well as UV radiation from lightning
strikes and transient luminous events, micro-meteors and space debris. The
first months of its operation in orbit have demonstrated an unexpectedly rich
variety of UV radiation in the atmosphere. We briefly review the design of TUS
and present a few examples of events recorded in a mode dedicated to
registering EECRs.Comment: 8 pages, to appear in the proceedings of UHECR2016, Kyoto, 11-14
October 2016; version 2: minor changes following referee's suggestions;
version 3: typo in the caption of Fig.2 fixe
Galaxy Formation Spanning Cosmic History
Over the past several decades, galaxy formation theory has met with
significant successes. In order to test current theories thoroughly we require
predictions for as yet unprobed regimes. To this end, we describe a new
implementation of the Galform semi-analytic model of galaxy formation. Our
motivation is the success of the model described by Bower et al. in explaining
many aspects of galaxy formation. Despite this success, the Bower et al. model
fails to match some observational constraints and certain aspects of its
physical implementation are not as realistic as we would like. The model
described in this work includes substantially updated physics, taking into
account developments in our understanding over the past decade, and removes
certain limiting assumptions made by this (and most other) semi-analytic
models. This allows it to be exploited reliably in high-redshift and low mass
regimes. Furthermore, we have performed an exhaustive search of model parameter
space to find a particular set of model parameters which produce results in
good agreement with a wide range of observational data (luminosity functions,
galaxy sizes and dynamics, clustering, colours, metal content) over a wide
range of redshifts. This model represents a solid basis on which to perform
calculations of galaxy formation in as yet unprobed regimes.Comment: MNRAS accepted. Extended version (with additional figures and details
of implementation) is available at http://www.galform.or
Graphite ionization vacuum gauge
Triode gauge with electron source, electron collector, and positive ion collector made from either graphite or carbon material extends low-pressure ranges of existing gauges by changing only materials used in construction. Advantages of graphite gauge stem from physical properties of graphite (or carbon)
Dark-matter decays and Milky Way satellite galaxies
We consider constraints on a phenomenological dark-matter model consisting of
two nearly degenerate particle species using observed properties of the Milky
Way satellite galaxy population. The two parameters of this model, assuming the
particle masses are >~ GeV, are v_k, the recoil speed of the daughter particle,
and tau, the lifetime of the parent particle. The satellite constraint that
spans the widest range of v_k is the number of satellites that have a mass
within 300 pc M300 > 5 x 10^6 solar masses, although constraints based on M300
in the classical dwarfs and the overall velocity function are competitive for
v_k >~ 50 km/s. In general, we find that tau <~ 30 Gyr is ruled out for 20 km/s
<~ v_k <~ 200 km/s, although we find that the limits on tau for fixed v_k can
change constraints by a factor of ~3 depending on the star-formation histories
of the satellites. We advocate using the distribution of M300 in Milky Way
satellites determined by next-generation all-sky surveys and follow-up
spectroscopy as a probe of dark-matter properties.Comment: 17 pages, 9 figures, submitted to Phys. Rev.
Seventh year projects and activities of the Environmental Remote Sensing Applications Laboratory (ERSAL)
There are no author-identified significant results in this report
Bose-Einstein Condensation of Excitons: Reply to Tikhodeev's Criticism
The extended version of our reply to Comment on ``Critical Velocities in
Exciton Superfluidity'' by S. G. Tikhodeev (Phys. Rev. Lett., 84 (2000), 3502
or from http://prl.aps.org/) is presented here. The principal question is
discussed: does the moving exciton-phonon packet contain the coherent
`nucleus', or the exciton-phonon condensate?Comment: 3 pages in LaTe
Initial comparisons of modular-sized, integrated utility systems and conventional systems for several building types
The results of a study of the application of a modular integrated utility system to six typical building types are compared with the application of a conventional utility system to the same facilities. The effects of varying the size and climatic location of the buildings and the size of the powerplants are presented. Construction details of the six building types (garden apartments, a high rise office building, high rise apartments, a shopping center, a high school, and a hospital) and typical site and floor plans are provided. The environmental effects, the unit size determination, and the market potential are discussed. The cost effectiveness of the various design options is not considered
New South Wales Vegetation classification and Assessment: Part 3, plant communities of the NSW Brigalow Belt South, Nandewar and west New England Bioregions and update of NSW Western Plains and South-western Slopes plant communities, Version 3 of the NSWVCA database
This fourth paper in the NSW Vegetation Classification and Assessment series covers the Brigalow Belt South-/1(BBS) and Nandewar (NAN) Bioregions and the western half of the New England Bioregion (NET), an area of 9.3 million hectares being 11.6% of NSW. It completes the NSWVCA coverage for the Border Rivers-Gwydir and Namoi CMA areas and records plant communities in the Central West and HunterβCentral Rivers CMA areas. In total, 585 plant communities are now classified in the NSWVCA covering 11.5 of the 18 Bioregions in NSW (78% of the State). Of these 226 communities are in the NSW Western Plains and 416 are in the NSW Western Slopes. 315 plant communities are classified in the BBS, NAN and west-NET Bioregions including 267 new descriptions since Version 2 was published in 2008. Descriptions of the 315 communities are provided in a 919 page report on the DVD accompanying this paper along with updated reports on other inland NSW bioregions and nine Catchment Management Authority areas fully or partly classified in the NSWVCA to date. A read-only version of Version 3 of the NSWVCA database is on the DVD for use on personal computers. A feature of the BBS and NAN Bioregions is the array of ironbark and bloodwood Eucalyptusdominated shrubby woodlands on sandstone and acid volcanic substrates extending from Dubbo to Queensland. This includes iconic natural areas such as Warrumbungle and Mount Kaputar National Parks and the 500,000 ha Pilliga Scrub forests. Large expanses of basalt-derived soils support grassy box woodland and native grasslands including those on the Liverpool Plains; near Moree; and around Inverell, most of which are cleared and threatened. Wetlands occur on sodic soils near Yetman and in large clay gilgais in the Pilliga region. Sedgelands are rare but occupy impeded creeks. Aeolian lunettes occur at Narran Lake and near Gilgandra. Areas of deep sand contain Allocasuarina, eucalypt mallee and Melaleuca uncinata heath. Tall grassy or ferny open forests occur on mountain ranges above 1000m elevation in the New England Bioregion and on the Liverpool Range while grassy box woodlands occupy lower elevations with lower rainfall and higher temperatures. The vegetation classification and assessment is based on over 100 published and unpublished vegetation surveys and map unit descriptions, expert advice, extra plot sampling and data analysis and over 25 000 km of road traverse with field checking at 805 sites. Key sources of data included floristic analyses produced in western regional forest assessments in the BBS and NAN Bioregions, floristic analyses in over 60 surveys of conservation reserves and analysis of plot data in the western NET Bioregion and covering parts of the Namoi and Border Rivers- Gwydir CMA areas. Approximately 60% of the woody native vegetation in the study area has been cleared resulting in large areas of βderivedβ native grasslands. As of June 2010, 7% of the area was in 136 protected areas and 127 of the 315 plant communities were assessed to be adequately protected in reserves. Using the NSWVCA database threat criteria, 15 plant communities were assessed as being Critically Endangered, 59 Endangered, 60 Vulnerable, 99 Near Threatened and 82 Least Concern. 61 of these communities are assessed as part of NSW or Commonwealth-listed Threatened Ecological Communities. Current threats include expanding dryland and irrigated cropping on alluvial plains, floodplains and gently undulating topography at lower elevations; over-grazing of steep hills; altered water tables and flooding regimes; localized mining; and the spread of exotic species, notably Coolatai Grass (Hyparrhenia hirta)
The Breeding Biology of the Western Tanager (Piranga Ludoviciana)
In 1969 a two-year study was undertaken in an effort to enlarge our knowledge of the life history of the western tanager (Piranga ludoviciana). Bent (1958) summarizes the literature on the western tanager, and a review of his work clearly shows an almost total absence of detailed information on the species\u27 life history. To obtain this information, observations were conducted from 1 May through 29 July 1969. A few observations were made during the 1968 breeding season
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