2,263 research outputs found
On the linear term correction for needlets/wavelets non-Gaussianity estimators
We derive the linear correction term for needlet and wavelet estimators of
the bispectrum and the non-linearity parameter fNL on cosmic microwave
background radiation data. We show that on masked WMAP-like data with
anisotropic noise, the error bars improve by 10-20% and almost reach the
optimal error bars obtained with the KSW estimator (Komatsu et al 2005). In the
limit of full-sky and isotropic noise, this term vanishes. We apply needlet and
wavelet estimators to the WMAP 7-year data and obtain our best estimate
fNL=37.5 \pm 21.8.Comment: 10 pages, submitted to Ap
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Keystone XL Pipeline: Overview and Recent Developments
[Excerpt] This report describes the Keystone XL Pipeline Project and the process that the State Department must complete to decide whether it will approve or deny TransCanada’s permit application. The report also discusses key energy security, economic, and environmental issues relevant to the State Department’s national interest determination. Some of these issues include perspectives among various stakeholders both in favor of and opposed to the construction of the pipeline. Finally, the report discusses the constitutional basis for the State Department’s authority to issue a Presidential Permit, and opponents’ possible challenges to this authority
CMB lensing and primordial squeezed non-Gaussianity
Squeezed primordial non-Gaussianity can strongly constrain early-universe
physics, but it can only be observed on the CMB after it has been
gravitationally lensed. We give a new simple non-perturbative prescription for
accurately calculating the effect of lensing on any squeezed primordial
bispectrum shape, and test it with simulations. We give the generalization to
polarization bispectra, and discuss the effect of lensing on the trispectrum.
We explain why neglecting the lensing smoothing effect does not significantly
bias estimators of local primordial non-Gaussianity, even though the change in
shape can be >~10%. We also show how tau_NL trispectrum estimators can be well
approximated by much simpler CMB temperature modulation estimators, and hence
that there is potentially a ~10-30% bias due to very large-scale lensing modes,
depending on the range of modulation scales included. Including dipole sky
modulations can halve the tau_NL error bar if kinematic effects can be
subtracted using known properties of the CMB temperature dipole. Lensing
effects on the g_NL trispectrum are small compared to the error bar. In
appendices we give the general result for lensing of any primordial bispectrum,
and show how any full-sky squeezed bispectrum can be decomposed into orthogonal
modes of distinct angular dependence.Comment: 22 pages, 6 figures; minor edits to match published versio
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Stephen Biko's Rhetorical Vision of Black Consciousness
Stephen Biko was a black leader in South Africa who
died in police custody on September 12, 1977. Biko's death
echoed within the Republic of South Africa and around the
world, showing that racial tensions in that country were
severe. At his death he was a hero to the black majority
and a threat to the white minority.
The rhetoric that survives reveals Biko's dominant
themes. Biko worked to create an awareness among blacks
that it was possible to combat white suppression. Four main
themes, I argue, emerge from a study of his rhetoric. They
are Black Humanity, Black Unity, Black Courage, and Black
Self-Reliance. These themes became part of the ideology
behind the Black Consciousness Movement and stood in
opposition to four themes of white dominance:
dehumanization, separation, fear, and control.
In his work on rhetoric and the construction of social
reality, Ernest G. Bormann suggests that certain "fantasy
themes" within a group's rhetoric "chain-out" and become the
"rhetorical vision" that a group holds in common. The
fantasy themes, and in turn the rhetorical vision, can
motivate the group to action.
The purpose of this study, then, is to analyze the
fantasy themes within Biko's rhetoric to learn more about
the role of rhetoric in social movements and in the
constitution and reconstitution of Black Consciousness
Optimisation of a Multi-Gravity Separator with Novel Modifications for the Recovery of Ferberite
This is the final version of the article. Available from MDPI via the DOI in this record.Tungsten is considered by the European Union as a critical raw material for future development due to its expected demand and scarcity of resource within Europe. It is therefore, critical to optimize European tungsten operations and maximise recoveries. The role of enhanced gravity/centrifugal concentrators in recovering tungsten from ultra-fine fractions should form an important part of this aim. Reported herein are the results of investigations to improve efficiency of Wolf Minerals’ Draklends mine, a major European tungsten mine, by recovering saleable material from a magnetic waste stream of a low-intensity magnetic separator using an enhanced gravity concentrator. The mine hosts wolframite and ferberite as the main tungsten bearing mineral species. A Mozley multi-gravity separator (MGS) C-900 was selected as it is suited to exploiting small variations in mineral density to affect a separation. Working with a current manufacturer, a novel scraping blade system was tested. To assess the MGS in a statistically valid manner, a response surface methodology was followed to determine optimal test conditions. The test programme showed that the most important parameters were drum speed and wash water rate. Under optimal conditions the model predicted that 40% of the tungsten could be recovered above the required grade of 43% WO3.This work is part of the OptimOre project. This project has received funding from the
European Union’s Horizon 2020 research and innovation programme under grant agreement No. 642201. Authors
are thankful to Wolf Minerals for providing material for experimentation and to Gravity Mining Ltd. for support
in undertaking experiments and providing the opportunity to test the modified low profile blades
A review of the application of non-intrusive infrared sensing for gas–liquid flow characterization
This paper reviews the use of non-intrusive optical infrared sensing for gas–liquid flow characterisation in pipes. The application of signal analysis techniques to infrared-derived temporal signal outputs enables the objective determination of flow characteristics such as flow regimes, phase fractions and total pressure drops. Key considerations for improving the performance of infrared sensors are discussed. These include global and local measurements, ray divergence, effects of ambient light and temperature variations. Most experimental studies have reported consistent and excellent results for flow regime identifications and phase fraction estimation but with a few validating total pressures drop from correlations and direct pressure measurements. Other gaps in research were highlighted; these include the use of pipes sizes greater than 0.005m for experimentation under high superficial velocities conditions greater than 10 m/s. The capabilities of infrared sensing as a standalone measurement for flow metering were considered a possibility via an inferential approach for phase volumetric rates. More so, the derived infrared sensing flow characteristics could be combined with available pressure–volume–temperature correlations in estimating mass flow rates of each phase. As a future development, a conceptual modification to surface installations using a transparent opaque coupling is suggested to overcome the accessibility limitation of infrared light penetration for opaque pipes
The Trans-Pacific Partnership Agreement: Looking Ahead to the Next Steps
Pressure has been building for the conclusion of the 12-country Trans-Pacific Partnership (TPP) negotiations. Getting the deal done is important, but the TPP is not just another free trade agreement (FTA). It represents the chance to set a trade agenda for the future across a wide range of topics for countries throughout the Asia-Pacific region. This means that the agreement should not be settled in haste. More importantly, it also means that key decisions need to be reached about broader issues related to the institutional structure of the TPP. These decisions must be made now, before the deal is closed, on issues such as how to create the TPP as a living agreement, the formation of a TPP Secretariat, and the clarification of entry conditions for future members such as the People’s Republic of China (PRC). These choices must be made deliberately and carefully even while officials are struggling with reaching closure on the most highly sensitive issues still remaining in the agreement. It will not be easy, but wise decisions are necessary now to ensure the long-term success of the TPP
Creating Positive Learning Environments in Early Childhood Using Teacher-Generated Prosocial Lessons
A primary motivation for people to behave as they do is the need to belong socially to a group and to have relevance. A positive learning environment for young students is created when students are recognized and accepted by their peers and their teachers, and studies reveal that in such environments, students perform better academically and tend to have fewer behavioral issues. These environments may also act as a buffer against school dropout rates. This study examined whether teaching prosocial lessons to first-grade students in the southeastern United States would create positive learning environments for children who otherwise may not be recognized and accepted by their peers and also examined the relationship of teacher evaluations of observable classroom behaviors by their students with student recognition by peers. This study confirms the relevance of prosocial lessons in the creation of positive learning environments for young students
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