490 research outputs found
How portable is level-0 behavior? A test of level-k theory in game with non-neutral frames
We test the portability of level-0 assumptions in level-k theory in an experimental investigation of behavior in Coordination, Discoordination, and Hide and Seek games with common, non-neutral frames. Assuming that level-0 behavior depends only on the frame, we derive hypotheses that are independent of prior assumptions abou tsalience. Those hypotheses are not confirmed. Our findings contrast with previous research which has fitted parameterized level-k models to Hide and Seek data. We show that, as a criterion of successful explanation, the existence of a plausible model that replicates the main patterns in these data has a high probability of false positives
Empirical line lists and absorption cross sections for methane at high temperature
Hot methane is found in many "cool" sub-stellar astronomical sources
including brown dwarfs and exoplanets, as well as in combustion environments on
Earth. We report on the first high-resolution laboratory absorption spectra of
hot methane at temperatures up to 1200 K. Our observations are compared to the
latest theoretical spectral predictions and recent brown dwarf spectra. The
expectation that millions of weak absorption lines combine to form a continuum,
not seen at room temperature, is confirmed. Our high-resolution transmittance
spectra account for both the emission and absorption of methane at elevated
temperatures. From these spectra, we obtain an empirical line list and
continuum that is able to account for the absorption of methane in high
temperature environments at both high and low resolution. Great advances have
recently been made in the theoretical prediction of hot methane, and our
experimental measurements highlight the progress made and the problems that
still remain.Comment: 9 pages, 5 figures and 3 tables. For associated online data see
http://dx.doi.org/10.1088/0004-637X/813/1/1
The developments of minimum wage legislation in the United Kingdom
This thesis presents an examination of the legal developments made in wage
regulations within the United Kingdom. The period that has been chosen for
examination spans from the 18th to the 21st century. This period was chosen for
examination due to the huge social, political, economic and legal changes that took
place within the United Kingdom during these years. These changes saw major
developments made within the field of employment law and worker’s rights in general.
This period also saw the enactment of the first piece of legislation that regulated wages
in the industrial world – the Trade Boards Act of 1909.
This thesis examines the journey that the United Kingdom took since the enactment
of the 1909 Act that lead to the current system of wage regulation – The National
Minimum Wage Act 1998.
This thesis has also touched on various campaigns that have called for a Living Wage
and has assessed what impact these have had on Government policy. It looks at the
National Living Wage, that was introduced in 2016, and examines whether this is a
living wage in the sense of the word
Referencing Sources of Molecular Spectroscopic Data in the Era of Data Science: Application to the HITRAN and AMBDAS Databases
The application described has been designed to create bibliographic entries
in large databases with diverse sources automatically, which reduces both the
frequency of mistakes and the workload for the administrators. This new system
uniquely identifies each reference from its digital object identifier (DOI) and
retrieves the corresponding bibliographic information from any of several
online services, including the SAO/NASA Astrophysics Data Systems (ADS) and
CrossRef APIs. Once parsed into a relational database, the software is able to
produce bibliographies in any of several formats, including HTML and BibTeX,
for use on websites or printed articles. The application is provided
free-of-charge for general use by any scientific database. The power of this
application is demonstrated when used to populate reference data for the HITRAN
and AMBDAS databases as test cases. HITRAN contains data that is provided by
researchers and collaborators throughout the spectroscopic community. These
contributors are accredited for their contributions through the bibliography
produced alongside the data returned by an online search in HITRAN. Prior to
the work presented here, HITRAN and AMBDAS created these bibliographies
manually, which is a tedious, time-consuming and error-prone process. The
complete code for the new referencing system can be found at
\url{https://github.com/hitranonline/refs}.Comment: 11 pages, 5 figures, already published online at
https://doi.org/10.3390/atoms802001
EXPERIMENTAL LINE LISTS OF HOT METHANE
Line lists of CH at high temperatures (up to 900C) have been produced between 2500 and 5000 cm. This spectral range contains the pentad and octad regions, and includes numerous fundamental, overtone and hot bands. Our method makes use of a quartz sample cell that is heated by a tube furnace. Four spectra are then recorded at each temperature using a Fourier transform infrared spectrometer at high resolution (0.02 cm). By combining these four spectra at each temperature, the emission and absorption from the cell and molecules are accounted for, and we obtain the true transmission spectrum of hot CH. Analysis of this series of spectra enables the production of line lists that include positions, intensities and empirical lower state energies.
We also compare our line lists to the best available theoretical line lists at high temperatures. Whilst our experimental line lists contain fewer lines than theoretical line lists, we are able to demonstrate the quality of our observed spectra by considering our observations as absorption cross sections. This is important at elevated temperatures, when numerous blended lines appear as a continuum
HYDROGEN AND NITROGEN BROADENED ETHANE AND PROPANE ABSORPTION CROSS SECTIONS
High-resolution infrared absorption cross sections are presented for the band of ethane (CH) at 823 cm. These cross sections make use of spectra recorded at the Australian Synchrotron using a Fourier transform infrared spectrometer with maximum resolution of 0.00096 cm. The spectra have been recorded at 150, 120 and 90 K for hydrogen and nitrogen broadened CH. They cover appropriate temperatures, pressures and broadening gases associated with the atmospheres of the Outer Planets and Titan, and will improve atmospheric retrievals. The THz/Far-IR beamline at the Australian Synchrotron is unique in combining a high-resolution Fourier transform spectrometer with an �enclosive flow cooling� (EFC) cell designed to study molecules at low temperatures. The EFC cell is advantageous at temperatures for which the vapor pressure is very low, such as CH at 90 K.
Hydrogen broadened absorption cross sections of propane between 700 and 1200 cm will also be presented based on spectra obtained at the Canadian Light Source
Exploring Halo Substructure with Giant Stars IV: The Extended Structure of the Ursa Minor Dwarf Spheroidal
We present a large area photometric survey of the Ursa Minor dSph. We
identify UMi giant star candidates extending to ~3 deg from the center of the
dSph. Comparison to previous catalogues of stars within the tidal radius of UMi
suggests that our photometric luminosity classification is 100% accurate. Over
a large fraction of the survey area, blue horizontal branch stars associated
with UMi can also be identified. The spatial distribution of both the UMi giant
stars and the BHB stars are remarkably similar, and a large fraction of both
samples of stars are found outside the tidal radius of UMi. An isodensity
contour map of the stars within the tidal radius of UMi reveals two
morphological peculiarities: (1) The highest density of dSph stars is offset
from the center of symmetry of the outer isodensity contours. (2) The overall
shape of the outer contours appear S-shaped. We find that previously determined
King profiles with ~50' tidal radii do not fit well the distribution of our UMi
stars. A King profile with a larger tidal radius produces a reasonable fit,
however a power law with index -3 provides a better fit for radii > 20'. The
existence of UMi stars at large distances from the core of the galaxy, the
peculiar morphology of the dSph within its tidal radius, and the shape of its
surface density profile all suggest that UMi is evolving significantly due to
the tidal influence of the Milky Way. However, the photometric data on UMi
stars alone does not allow us to determine if the candidate extratidal stars
are now unbound or if they remain bound to the dSph within an extended dark
matter halo. (Abridged)Comment: accepted by AJ, 32 pages, 15 figures, emulateapj5 styl
Origin and extent of the opacity challenge for atmospheric retrievals of WASP-39 b
As the James Webb Space Telescope (JWST) came online last summer, we entered
a new era of astronomy. This new era is supported by data products of
unprecedented information content that require novel reduction and analysis
techniques. Recently, Niraula et al. 2022 (N22) highlighted the need for
upgraded opacity models to prevent facing a model-driven accuracy wall when
interpreting exoplanet transmission spectra. Here, we follow the same approach
as N22 to explore the sensitivity of inferences on the atmospheric properties
of WASP-39 b to the opacity models used. We find that the retrieval of the main
atmospheric properties from this first JWST exoplanet spectrum is mostly
unaffected by the current state of the community's opacity models. Abundances
of strong opacity sources like water and carbon dioxide are reliably
constrained within 0.30 dex, beyond the 0.50 dex accuracy wall reported
in N22. Assuming the completeness and accuracy of line lists, N22's accuracy
wall is primarily driven by model uncertainties on broadening coefficients and
far-wing behaviors, which we find to have marginal consequences for
interpreting the transmission spectra of large, hot, high-metallicity
atmospheres such as WASP-39 b, in opposition to emission spectra and climate
modeling which depend on deeper parts of a planetary atmosphere. The origin of
the opacity challenge in the retrieval of metal-rich hot Jupiters via
transmission spectroscopy will thus mostly stem from the incompleteness and
inaccuracy of line lists.Comment: 10 Pages, 6 Figure
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