17,421 research outputs found
Two-Spirit Indigenous Americans: Fact not Fiction
This paper examines the narratives of Two-Spirit Indigenous Americans who have been oppressed by heteropatriarchal norms of colonization. Two-spirit creation stories are explored to show the prevalence and importance of their identities prior to contact with Euro-American settlers and the evolution of violence, exclusion, and marginalization due to colonization.The term Two-Spirit is examined as a cultural identity of the Indigenous Americans. Finally, the paper looks at how Two-Spirit scholars are looking to combine Queer Theory with Indigenous Studies to deconstruct colonial heteropatriarchal America
Nitrates in surface waters, inputs and seasonality: Phase 2
Changes in management practices and agricultural productivity over the past twenty years have lead to nitrate pollution and eutrophication of lakes and rivers. Information on nitrate concentrations and discharge has been collected on the River Frome at East Stoke since 1965, using the same analytical nitrate method so that the results are comparable. These records of weekly spot values of nitrate concentration and daily mean discharges have been analysed for trends and seasonal patterns in both concentration and nitrate loadings. In this extension of our nitrate contract, a new automated method of intensive sampling has been used to monitor short-term variability and to assess how well similar routine (weekly) sampling schemes can represent the true nitrate record
UVMULTIFIT: A versatile tool for fitting astronomical radio interferometric data
The analysis of astronomical interferometric data is often performed on the
images obtained after deconvolution of the interferometer's point spread
function (PSF). This strategy can be understood (especially for cases of sparse
arrays) as fitting models to models, since the deconvolved images are already
non-unique model representations of the actual data (i.e., the visibilities).
Indeed, the interferometric images may be affected by visibility gridding,
weighting schemes (e.g., natural vs. uniform), and the particulars of the
(non-linear) deconvolution algorithms. Fitting models to the direct
interferometric observables (i.e., the visibilities) is preferable in the cases
of simple (analytical) sky intensity distributions. In this paper, we present
UVMULTIFIT, a versatile library for fitting visibility data, implemented in a
Python-based framework. Our software is currently based on the CASA package,
but can be easily adapted to other analysis packages, provided they have a
Python API. We have tested the software with synthetic data, as well as with
real observations. In some cases (e.g., sources with sizes smaller than the
diffraction limit of the interferometer), the results from the fit to the
visibilities (e.g., spectra of close by sources) are far superior to the output
obtained from the mere analysis of the deconvolved images. UVMULTIFIT is a
powerful improvement of existing tasks to extract the maximum amount of
information from visibility data, especially in cases close to the
sensitivity/resolution limits of interferometric observations.Comment: 10 pages, 4 figures. Accepted in A&A. Code available at
http://nordic-alma.se/support/software-tool
Discrimination and synthesis of recursive quantum states in high-dimensional Hilbert spaces
We propose an interferometric method for statistically discriminating between
nonorthogonal states in high dimensional Hilbert spaces for use in quantum
information processing. The method is illustrated for the case of photon
orbital angular momentum (OAM) states. These states belong to pairs of bases
that are mutually unbiased on a sequence of two-dimensional subspaces of the
full Hilbert space, but the vectors within the same basis are not necessarily
orthogonal to each other. Over multiple trials, this method allows
distinguishing OAM eigenstates from superpositions of multiple such
eigenstates. Variations of the same method are then shown to be capable of
preparing and detecting arbitrary linear combinations of states in Hilbert
space. One further variation allows the construction of chains of states
obeying recurrence relations on the Hilbert space itself, opening a new range
of possibilities for more abstract information-coding algorithms to be carried
out experimentally in a simple manner. Among other applications, we show that
this approach provides a simplified means of switching between pairs of
high-dimensional mutually unbiased OAM bases
Tagging amongst friends: an exploration of social media exchange on mobile devices
Mobile social software tools have great potential in transforming the way users communicate
on the move, by augmenting their everyday environment with pertinent information from
their online social networks. A fundamental aspect to the success of these tools is in
developing an understanding of their emergent real-world use and also the aspirations of
users; this thesis focuses on investigating one facet of this: the exchange of social media. To
facilitate this investigation, three mobile social tools have been developed for use on locationaware
smartphone handsets. The first is an exploratory social game, 'Gophers' that utilises
task oriented gameplay, social agents and GSM cell positioning to create an engaging
ecosystem in which users create and exchange geotagged social media. Supplementing this is
a pair of social awareness and tagging services that integrate with a user's existing online
social network; the 'ItchyFeet' service uses GPS positioning to allow the user and their social
network peers to collaboratively build a landscape of socially important geotagged locations,
which are used as indicators of a user's context on their Facebook profile; likewise
'MobiClouds' revisits this concept by exploring the novel concept of Bluetooth 'people
tagging' to facilitate the creation of tags that are more indicative of users' social surroundings.
The thesis reports on findings from formal trials of these technologies, using groups of
volunteer social network users based around the city of Lincoln, UK, where the incorporation
of daily diaries, interviews and automated logging precisely monitored application use.
Through analysis of trial data, a guide for designers of future mobile social tools has been
devised and the factors that typically influence users when creating tags are identified. The
thesis makes a number of further contributions to the area. Firstly, it identifies the natural
desire of users to update their status whilst mobile; a practice recently popularised by
commercial 'check in' services. It also explores the overarching narratives that developed over
time, which formed an integral part of the tagging process and augmented social media with a
higher level meaning. Finally, it reveals how social media is affected by the tag positioning
method selected and also by personal circumstances, such as the proximity of social peers
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