890 research outputs found
The Astronomy of the Kamilaroi People and their Neighbours
The Kamilaroi people and their neighbours, the Euahlayi, Ngemba, and
Murrawarri, are an Aboriginal cultural grouping located in the northwest and
north central of New South Wales. They have a rich history, but have been
missed in much of the literature concerned with sky knowledge in culture. This
study collected stories, some of which have not previously been reported in an
academic format, from Aboriginal people practicing their culture, augmented
with stories from the literature, and analysed the data to create a database of
sky knowledge that will be added to the larger body of Aboriginal cultural
knowledge in Australia. We found that there is a strong sky culture reflected
in the stories, and we also explored the stories for evidence of an
ethnoscientific approach to knowledge of the sky.Comment: 28 pages, 9 figure
Orientations of linear stone arrangements in New South Wales
We test the hypothesis that Aboriginal linear stone arrangements in New South
Wales (NSW) are oriented to cardinal directions. We accomplish this by
measuring the azimuths of stone arrangements described in site cards from the
NSW Aboriginal Heritage Information Management System. We then survey a subset
of these sites to test the accuracy of information recorded on the site cards.
We find a preference recorded in the site cards for cardinal orientations among
azimuths. The field surveys show that the site cards are reasonably accurate,
but the surveyors probably did not correct for magnetic declinations. Using
Monte Carlo statistics, we show that these preferred orientations did not occur
by chance and that Aboriginal people deliberately aligned these arrangements to
the approximate cardinal directions. We briefly explore possible reasons for
these preferred orientations and highlight the need for future work.Comment: Australian Archaeology, Volume 75 (December 2012), accepte
A New Discriminator for Gamma-Ray Burst Classification: The Epeak-Fluence Energy Ratio
Using the derived gamma-ray burst E_peak and fluences from the complete BATSE
5B Spectral Catalog, we study the ensemble characteristics of the
E_peak-fluence relation for GRBs. This relation appears to be a physically
meaningful and insightful fundamental discriminator between long and short
bursts. We discuss the results of the lower limit test of the E_peak-E_iso
relations in the E_peak-fluence plane for BATSE bursts with no observed
redshift. Our results confirm the presence of two GRB classes as well as
heavily suggesting two different GRB progenitor types.Comment: 8 pages, 3 figures, accepted for publication in Ap
Star Maps and Travelling to Ceremonies -- the Euahlayi People and Their Use of the Night Sky
The Euahlayi people are an Australian Aboriginal language group located in
north-central New South Wales and south-central Queensland. They have a rich
culture of astronomy, and use of the night sky in resource management. Like
several other Aboriginal peoples, they did not travel extensively at night, and
so were assumed not to use the night sky for navigation. This study has
confirmed that they, like most other Aboriginal groups, travelled extensively
outside their own country for purposes of trade and ceremonies. We also found
that, previously unknown, they used star maps in the night sky for learning and
remembering waypoints along their routes of travel, but not for actual
navigation. Further research may find that this was common to many Aboriginal
groups in Australia.Comment: 17 pages, 8 figure
Who stands in the way of women? Open vs. closed lists and candidate gender in Estonia
The literature on women's descriptive representation has looked at the debate on open and closed lists as a choice between electoral systems. This article instead focuses on whether voters or the parties are biased against female candidates. Using data from six Estonian elections, the article finds that voters are not consistently biased against female candidates and open lists do not necessarily decrease women's representation. However, unknown and non-incumbent female candidates fare significantly worse than similar men. The analysis also shows that parties do not place women in electable positions on closed lists, and closed lists do not improve women's representation
Form factor for a family of quantum graphs: An expansion to third order
For certain types of quantum graphs we show that the random-matrix form
factor can be recovered to at least third order in the scaled time from
periodic-orbit theory. We consider the contributions from pairs of periodic
orbits represented by diagrams with up to two self-intersections connected by
up to four arcs and explain why all other diagrams are expected to give
higher-order corrections only.
For a large family of graphs with ergodic classical dynamics the diagrams
that exist in the absence of time-reversal symmetry sum to zero. The mechanism
for this cancellation is rather general which suggests that it may also apply
at higher-orders in the expansion. This expectation is in full agreement with
the fact that in this case the linear- contribution, the diagonal
approximation, already reproduces the random-matrix form factor for .
For systems with time-reversal symmetry there are more diagrams which
contribute at third order. We sum these contributions for quantum graphs with
uniformly hyperbolic dynamics, obtaining , in agreement with
random-matrix theory. As in the previous calculation of the leading-order
correction to the diagonal approximation we find that the third order
contribution can be attributed to exceptional orbits representing the
intersection of diagram classes.Comment: 23 pages (including 4 fig.) - numerous typos correcte
Rural Food Pantry Users’ Stigma and Safety Net Food Programs
Increasing numbers of individuals in our community have been seeking local food pantry assistance. Previous studies of food pantries found that users show low rates of governmental aid receipt, especially in rural areas. We assessed evidence that suggests that post-recession need has mitigated rural reluctance to pursue government assistance. The inadequacy of government and local food assistance to address the problem of food insecurity in our community is discussed
Limits on the cosmological abundance of supermassive compact objects from a millilensing search in gamma-ray burst data
A new search for the gravitational lens effects of a significant cosmological
density of supermassive compact objects (SCOs) on gamma-ray bursts has yielded
a null result. We inspected the timing data of 774 BATSE-triggered GRBs for
evidence of millilensing: repeated peaks similar in light-curve shape and
spectra. Our null detection leads us to conclude that, in all candidate
universes simulated, is favored for , while in some universes and mass ranges the density
limits are as much as 10 times lower. Therefore, a cosmologically significant
population of SCOs near globular cluster mass neither came out of the
primordial universe, nor condensed at recombination.Comment: 14 pages including 3 figures, appeared 2001 January 2
Synthesizing and tuning chemical reaction networks with specified behaviours
We consider how to generate chemical reaction networks (CRNs) from functional
specifications. We propose a two-stage approach that combines synthesis by
satisfiability modulo theories and Markov chain Monte Carlo based optimisation.
First, we identify candidate CRNs that have the possibility to produce correct
computations for a given finite set of inputs. We then optimise the reaction
rates of each CRN using a combination of stochastic search techniques applied
to the chemical master equation, simultaneously improving the of correct
behaviour and ruling out spurious solutions. In addition, we use techniques
from continuous time Markov chain theory to study the expected termination time
for each CRN. We illustrate our approach by identifying CRNs for majority
decision-making and division computation, which includes the identification of
both known and unknown networks.Comment: 17 pages, 6 figures, appeared the proceedings of the 21st conference
on DNA Computing and Molecular Programming, 201
Time-Resolved Spectroscopy of the 3 Brightest and Hardest Short Gamma-Ray Bursts Observed with the FGST Gamma-Ray Burst Monitor
From July 2008 to October 2009, the Gamma-ray Burst Monitor (GBM) on board
the Fermi Gamma-ray Space Telescope (FGST) has detected 320 Gamma-Ray Bursts
(GRBs). About 20% of these events are classified as short based on their T90
duration below 2 s. We present here for the first time time-resolved
spectroscopy at timescales as short as 2 ms for the three brightest short GRBs
observed with GBM. The time-integrated spectra of the events deviate from the
Band function, indicating the existence of an additional spectral component,
which can be fit by a power-law with index ~-1.5. The time-integrated Epeak
values exceed 2 MeV for two of the bursts, and are well above the values
observed in the brightest long GRBs. Their Epeak values and their low-energy
power-law indices ({\alpha}) confirm that short GRBs are harder than long ones.
We find that short GRBs are very similar to long ones, but with light curves
contracted in time and with harder spectra stretched towards higher energies.
In our time-resolved spectroscopy analysis, we find that the Epeak values range
from a few tens of keV up to more than 6 MeV. In general, the hardness
evolutions during the bursts follows their flux/intensity variations, similar
to long bursts. However, we do not always see the Epeak leading the light-curve
rises, and we confirm the zero/short average light-curve spectral lag below 1
MeV, already established for short GRBs. We also find that the time-resolved
low-energy power-law indices of the Band function mostly violate the limits
imposed by the synchrotron models for both slow and fast electron cooling and
may require additional emission processes to explain the data. Finally, we
interpreted these observations in the context of the current existing models
and emission mechanisms for the prompt emission of GRBs.Comment: 14 pages, 10 figures, 9 tables, Accepted for publication in the
Astrophysical Journal September, 23 2010 (Submitted May, 16 2010)
Corrections: 1 reference updated, figure 10 captio
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