695 research outputs found
Looking at the Future of Volunteer Tourism: Commodification, Altruism and Accreditation
Community Development in Volunteer Tourism Destinations
Description International Volunteer Tourism: Integrating Travellers and Communitie
Introduction-Beyond Experiences that Make a Difference
International Volunteer Tourism: Integrating Travellers and Communitie
Freezing-in hadrophilic dark matter at low reheating temperatures
If the reheating temperature at the end of inflation is low, of order 10 MeV,
then dark matter produced through ultraviolet freeze-in has a large direct
detection cross section. We study such a scenario in which dark matter is
hadrophilic. This leads to dark matter-nucleon scattering cross sections of
interest for near-future experiments for dark matter masses in the range of 100
keV-100 MeV. We explore how these predictions vary if reheating is
non-instantaneous.Comment: 17+8 pages, 7 figure
Classical Coulomb three-body problem in collinear eZe configuration
Classical dynamics of two-electron atom and ions H, He, Li,
Be,... in collinear eZe configuration is investigated. It is revealed
that the mass ratio between necleus and electron plays an important role
for dynamical behaviour of these systems. With the aid of analytical tool and
numeircal computation, it is shown that thanks to large mass ratio ,
classical dynamics of these systems is fully chaotic, probably hyperbolic.
Experimental manifestation of this finding is also proposed.Comment: Largely rewritten. 21 pages. All figures are available in
http://ace.phys.h.kyoto-u.ac.jp/~sano/3-body/index.htm
Multiwavelength study of the high-latitude cloud L1642: chain of star formation
L1642 is one of the two high galactic latitude (|b| > 30deg) clouds confirmed
to have active star formation. We examine the properties of this cloud,
especially the large-scale structure, dust properties, and compact sources in
different stages of star formation. We present high-resolution far-infrared and
submm observations with the Herschel and AKARI satellites and mm observations
with the AzTEC/ASTE telescope, which we combined with archive data from near-
and mid-infrared (2MASS, WISE) to mm observations (Planck). The Herschel
observations, combined with other data, show a sequence of objects from a cold
clump to young stellar objects at different evolutionary stages. Source B-3
(2MASS J04351455-1414468) appears to be a YSO forming inside the L1642 cloud,
instead of a foreground brown dwarf, as previously classified. Herschel data
reveal striation in the diffuse dust emission around L1642. The western region
shows striation towards NE and has a steeper column density gradient on its
southern side. The densest central region has a bow-shock like structure
showing compression from the west and a filamentary tail extending towards
east. The differences suggest that these may be spatially distinct structures,
aligned only in projection. We derive values of the dust emission cross-section
per H nucleon for different regions of the cloud. Modified black-body fits to
the spectral energy distribution of Herschel and Planck data give emissivity
spectral index beta values 1.8-2.0 for the different regions. The compact
sources have lower beta values and show an anticorrelation between T and beta.
Markov chain Monte Carlo calculations demonstrate the strong anticorrelation
between beta and T errors and the importance of mm Planck data in constraining
the estimates. L1642 reveals a more complex structure and sequence of star
formation than previously known.Comment: 22 pages, 18 figures, accepted to Astronomy & Astrophysics; abstract
shortened and figures reduced for astrop
As you like it: Understanding the relationship between packing design and accessibility
Accessible packaging is continually receiving greater attention as an ageing population becomes a primary driver behind inclusive design. As we age, our strength dexterity and some cognitive functions decline. For this reason, the ease of interaction
with simple tasks in daily living becomes an ever increasing concern. ISO 17480
“Packaging Guidelines” consider capability issues relating to packaging and ageing
to broadly come under three areas, namely, strength, dexterity, and cognition.
Significant previous work has been undertaken looking at the issue of strength on
packaging accessibility, with fewer studies looking at the relationship between the
physical demands of dexterity and the understanding of how to open the pack. In this
previous work, there has been little attempt to quantify the effect of the affordances,
perceptual information and symbology, and the physical demands of the pack and
how this relates to accessibility. Hence, this exploratory study seeks to use motion
capture and a dexterity test, along with a cognitive demand test to study this
relationship and any changes with age. This research indicates that the dexterous
demands of a task are linked to the cognitive demands; and thus in reaching a level
of comprehension of the pack and how to access the product a subject may interact
with a pack effectivel
New Young Star Candidates in BRC 27 and BRC 34
We used archival Spitzer Space Telescope mid-infrared data to search for
young stellar objects (YSOs) in the immediate vicinity of two bright-rimmed
clouds, BRC 27 (part of CMa R1) and BRC 34 (part of the IC 1396 complex). These
regions both appear to be actively forming young stars, perhaps triggered by
the proximate OB stars. In BRC 27, we find clear infrared excesses around 22 of
the 26 YSOs or YSO candidates identified in the literature, and identify 16 new
YSO candidates that appear to have IR excesses. In BRC 34, the one
literature-identified YSO has an IR excess, and we suggest 13 new YSO
candidates in this region, including a new Class I object. Considering the
entire ensemble, both BRCs are likely of comparable ages, within the
uncertainties of small number statistics and without spectroscopy to confirm or
refute the YSO candidates. Similarly, no clear conclusions can yet be drawn
about any possible age gradients that may be present across the BRCs.Comment: 54 pages, 19 figures, accepted by A
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