2,162 research outputs found
Infrared spectroscopy of the largest known trans-neptunian object 2001 KX76
We report complete near-infrared (0.9-2.4 m) spectral observations of
the largest know trans-neptunian objects (TNO) 28976 = 2001 KX taken in
two different nights using the new Near Infrared Camera Spectrometer (NICS)
attached to the 3.56m Telescopio Nazionale Galileo (TNG). The spectra are
featureless and correspond to a neutral colored object. Our observations
indicate that the surface of 2001 KX is probably highly evolved due to
long term irradiation, and that collisional resurfacing processes have not
played an important role in its evolution.Comment: 1 Latex file, 2 postscript files. A&A in pres
Categories, Allegories, and Circuit Design
Languages based upon binary relations offer an appealing setting for constructing programs from specifications. For example, working with relations rather than functions allows specifications to be more abstract (for example, many programs have a natural specification using the converse operator on relations), and affords a natural treatment of non-determinism in specifications. In this paper we present a novel pictorial interpretation of relational terms as simple pictures of circuits, and a soundness/completeness result that allows relational equations to be proved by pictorial reasoning
StrathSat-R : Deploying inflatable CubeSat structures in micro gravity
This paper presents the concepts, objectives and design of a student-led sounding rocket experiment which shall test novel inflatable devices in space conditions. This experiment is envisaged as the first step towards developing a CubeSat programme at the University of Strathclyde, which can exploit the novel concepts developed and the technical skills gained. The experiment itself aims to test novel, student developed, inflatable space structures in micro gravity and reduced pressure conditions. It consists of three distinct sections, the ejection housing on the rocket and the two ejectable modules that are based on CubeSat architecture. Shortly before reaching apogee, the two modules are ejected from the rocket and will deploy their own inflating structure during free flight. After landing, the ejectable modules recovery will rely upon a GPS position relayed to the team from the module by Globalstar transmission and a RF beacon for tracking with the recovery helicopter. The two modules carry two different structures resulting in distinct mission objectives: The aim of FRODO is to deploy an experimental passive de-orbiting system for high altitude spacecraft which will in the future utilise solar radiation pressure for orbit removal. The aim of SAM is to serve as a technology demonstrator for the residual air deployment method of a smart bio-inspired space structure. This paper contains details about the science objectives of the mission and how they will be achieved, its experimental design and the management of the student-led project
Herbicide impacts on exotic grasses and a population of the critically endangered herb "Calystegia affinis" (Convolvulaceae) on Lord Howe Island
Introduced perennial grasses are capable of altering the habitat of native species, causing reductions in population size and vigour, and potentially affecting life-history processes such as survival, pollination and seedling recruitment. We examined the utility of herbicide treatment on two exotic grasses, Pennisetum clandestinum (Kikuyu) and Stenotaphrum secundatum (Buffalo grass) to restore the habitat of Calystegia affinis, a critically endangered species endemic to Lord Howe and Norfolk Islands. Using two herbicides, Asset (designed to affect only grasses) and Glyphosate (a general herbicide), we compared effectiveness in reducing grass cover on a population of Calystegia affinis. We protected Calystegia plants from the herbicides by ensuring their leaves were covered by plastic bags during herbicide application. Both herbicides were similarly effective in reducing grass cover after four weeks and had no noticeable adverse affect on Calystegia (suggesting the plastic bag protection was effective). After 26 weeks, Glyphosate was more effective in maintaining a reduced grass cover. Plots treated with either herbicide had a greater relative increase in abundance of Calystegia stems compared to untreated controls. The Glyphosate treatment resulted in the greatest relative increase in stem abundance, but this was not significantly greater than in the Asset treatment. We consider that spraying with Glyphosate treatment, with follow-up monitoring and spot-spraying, will assist the recovery of the Calystegia affinis population. Ultimately, the maintenance of a weed-free zone at the forest edge will provide suitable habitat for additional recruitment of this and other native species
Distributed Sensor Logging: As Easy as a Mesh of Yoyos
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The Mass Gathering Data Acquisition and Analysis (MaGDAA) project involved the development of hardware and software solutions to facilitate the rapid and effective collection of autonomous and survey based data during mass gathering events. The aim of the project was the development and trial of a purpose-built Open Hardware based environment monitoring sensor prototypes using IOIO (pronounced “yoyo”) boards. Data from these sensors, and other devices, was collected using Open Source software running on Android powered mobile phones, tablets and other open hardware based platforms. Data was shared using a Wi-Fi mesh network based on an Open Source project called The Serval Project. Additional data in the form of survey based questionnaires were collected using ODK Collect, one of the applications in the Open Data Kit suite. The MaGDAA project demonstrated that it is possible for researchers (through the use of Open Source software and Open Hardware) to own, visualise, and share data without the difficulties of setting up and maintaining servers. MaGDAA proved to be an effective infrastructure independent sensor logging network that enables a broad range of data collection (demographic, predispositions, motivations, psychosocial and environmental influencers and modifiers of audience behaviour, cultural value) in the field of mass gathering research
Neptune Trojans and Plutinos: colors, sizes, dynamics, and their possible collisions
Neptune Trojans and Plutinos are two subpopulations of trans-Neptunian
objects located in the 1:1 and the 3:2 mean motion resonances with Neptune,
respectively, and therefore protected from close encounters with the planet.
However, the orbits of these two kinds of objects may cross very often,
allowing a higher collisional rate between them than with other kinds of
trans-Neptunian objects, and a consequent size distribution modification of the
two subpopulations.
Observational colors and absolute magnitudes of Neptune Trojans and Plutinos
show that i) there are no intrinsically bright (large) Plutinos at small
inclinations, ii) there is an apparent excess of blue and intrinsically faint
(small) Plutinos, and iii) Neptune Trojans possess the same blue colors as
Plutinos within the same (estimated) size range do.
For the present subpopulations we analyzed the most favorable conditions for
close encounters/collisions and address any link there could be between those
encounters and the sizes and/or colors of Plutinos and Neptune Trojans. We also
performed a simultaneous numerical simulation of the outer Solar System over 1
Gyr for all these bodies in order to estimate their collisional rate.
We conclude that orbital overlap between Neptune Trojans and Plutinos is
favored for Plutinos with large libration amplitudes, high eccentricities, and
small inclinations. Additionally, with the assumption that the collisions can
be disruptive creating smaller objects not necessarily with similar colors, the
present high concentration of small Plutinos with small inclinations can thus
be a consequence of a collisional interaction with Neptune Trojans and such
hypothesis should be further analyzed.Comment: 15 pages, 9 figures, 6 tables, accepted for publication in A&
The water ice rich surface of (145453) 2005 RR43: a case for a carbon-depleted population of TNOs?
Recent results suggest that there is a group of TNOs (2003 EL61 being the
biggest member), with surfaces composed of almost pure water ice and with very
similar orbital elements. We study the surface composition of another TNO that
moves in a similar orbit, 2005 RR43, and compare it with the surface
composition of the other members of this group. We report visible and
near-infrared spectra, obtained with the 4.2m William Herschel Telescope and
the 3.58m Telescopio Nazionale Galileo at the "Roque de los Muchachos"
Observatory (La Palma, Spain). The spectrum of 2005 RR43 is neutral in color in
the visible and dominated by very deep water ice absorption bands in the near
infrared (D= 70.3 +/- 2.1 % and 82.8 +/- 4.9 % at 1.5 \mu and 2.0 \mu
respectively). It is very similar to the spectrum of the group of TNOs already
mentioned. All of them present much deeper water ice absorption bands (D>40 %)
than any other TNO except Charon. Scattering models show that its surface is
covered by water ice, a significant fraction in crytalline state with no trace
(5 % upper limit) of complex organics. Possible scenarios to explain the
existence of this population of TNOs are discussed: a giant collision, an
originally carbon depleted composition, or a common process of continuous
resurfacing. We conclude that TNO 2005 RR43 is member of a group, may be a
population, of TNOs clustered in the space of orbital parameters that show
abundant water ice and no signs of complex organics. The lack of complex
organics in their surfaces suggests a significant smaller fraction of
carbonaceous volatiles like CH4 in this population than in "normal" TNOs. A
carbon depleted population of TNOs could be the origin of the population of
carbon depleted Jupiter family comets already noticed by A'Hearn et al. (1995).Comment: Final Version (Paper Accepted) 4 pages, 2 figures. Changed title,
abstract, discussio
Electrochemical mapping reveals direct correlation between heterogeneous electron-transfer kinetics and local density of states in diamond electrodes
Conducting carbon materials: A multi-microscopy approach shows that local heterogeneous electron-transfer rates at conducting diamond electrodes correlate with the local density of electronic states. This model of electroactivity is of considerable value for the rational design of conducting diamond electrochemical technologies, and also provides key general insights on electrode structure controls in electrochemical kinetic
Event Design in outdoor music festival audience behaviour (a critical transformative research note)
This work, a conceptual forward-looking paper, examines the management of audiences at music festivals now and indicates a critical manoeuvre of focus for the future. The theoretical objectives and conclusions of a body of work by Robertson – discussing and then proposing future models of festival leadership to support place and event sustainability – are applied to a body of work by Hutton et al., from 2011 to 2017, and Brown et al., in 2012, 2013 and 2016. It is argued that a more holistic construct of civic responsibility will emerge in what will necessarily be a post co-creative, co-productive future for many critical mass meeting experiences. Hutton and Brown provide vital insight as to how consideration of the social psychological domain of the outdoor music festival (OMF) audience is critical to a design of the experience that is both experientially satisfying/fulfilling and, importantly, safe. This work uses literature related to festival management and critical transformation to propose a theoretical position arising from a construct of: transformative civic responsibility; social trust (as a component of social capital); and positive psychology. The work considers the dynamics and importance of outdoor music festivals in turbulent socio-economic times, and the potential limitations of a behaviourist approach to future music festival crowd management. A case study research project was undertaken at a series of OMFs staged in South Australia and the results are used as examples of new forms of dynamic research for critical and turbulent times
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