Top polarisation studies in H−tH^-t and WtWt production

The polarisation of top quarks produced in high energy processes can be a very sensitive probe of physics beyond the Standard Model. The kinematical distributions of the decay products of the top quark can provide clean information on the polarisation of the produced top and thus can probe new physics effects in the top quark sector. We study some of the recently proposed polarisation observables involving the decay products of the top quark in the context of $H^-t$ and $Wt$ production. We show that the effect of the top polarisation on the decay lepton azimuthal angle distribution, studied recently for these processes at leading order in QCD, is robust with respect to the inclusion of next-to-leading order and parton shower corrections. We also consider the leptonic polar angle, as well as recently proposed energy-related distributions of the top decay products. We construct asymmetry parameters from these observables, which can be used to distinguish the new physics signal from the $Wt$ background and discriminate between different values of $\tan\beta$ and $m_{H^-}$ in a general type II two-Higgs doublet model. Finally, we show that similar observables may be useful in separating a Standard Model $Wt$ signal from the much larger QCD induced top pair production background.Comment: 33 pages, 35 figures, references adde

Alien Registration- White, Irene (Presque Isle, Aroostook County)

https://digitalmaine.com/alien_docs/33686/thumbnail.jp

Historical Trajectories of Disaster Risk in Dominica

The calamitous consequences of 2017 Hurricane Maria for the Caribbean island of Dominica highlighted the acute and increasing susceptibility of the region to disasters. Despite increasing international attention to disaster risk reduction, recovery from hazard events can be especially lengthy and difficult for small island developing states. In this article, we build on existing understandings of disaster risk as a physical and social condition, showing that historical processes are fundamental to understanding how conditions of risk emerge and persist over time. We take an integrated approach to analyzing the drivers of risk accumulation, using the example of Dominica, where processes set in motion during the colonial period have shaped the location of people and assets, the degree to which they might be harmed, the societal repercussions of that harm and the prospects for recovery. We focus on the underlying economic vulnerabilities and physical exposure to hazards created by agricultural, economic, and social practices, and successive disaster responses that have constrained recovery. Uncovering these historical drivers and persistent issues, elucidates lessons for pursuing a more resilient development trajectory, including through the promotion of economic restructuring and diversification, and land reform

Participatory arts for creativity in education (PACE) model: exploring the participatory arts as a potential model for fostering creativity in post-primary education

This research study set out to explore how creativity was being fostered within Participatory Arts initiatives, with a view to informing the design of a Participatory Arts model for education. The study explored two types of Participatory Arts initiatives, the first led by Upstate Theatre Project, a ‘pure’ Participatory Arts initiative, and the second led by Fighting Words, an ‘applied’ Participatory Arts initiative. In the context of this study, the aim was to provide an evidence base for, and articulate, the factors and processes underpinning climates for creativity, and the (pedagogic) approaches used to foster creativity in Participatory Arts initiatives, as well as exploring the enablement of beneficial outcomes across both Participatory Arts contexts. The study firstly affirmed that Participatory Arts initiatives foster creativity, and furthermore that the practices within these initiatives enable the type of ‘learning for creativity’ outcomes articulated by the National Council for Curriculum and Assessment (NCCA) in Ireland. The study further articulated the Participatory Arts for Creativity in Education (PACE) model, a three-layered guide on the principles, practices and processes that can be used to foster creativity. Moreover, the study revealed a series of vignettes of good practice with respect to the enablement of climates for creativity and processes for being creative. The recommendations include a call for the Department of Education and Skills (DES) and the NCCA in Ireland to review the current national guidelines on fostering creativity in education in light of the findings from this research study, and for a creativity toolkit to be developed based on the PACE model and accompanying vignettes, and implemented within workshops for practitioners (post-primary teachers, artist-tutors) aiming to foster creativity through the Participatory Arts process

Reefs at Risk: A Map-Based Indicator of Threats to the Worlds Coral Reefs

This report presents the first-ever detailed, map-based assessment of potential threats to coral reef ecosystems around the world. "Reefs at Risk" draws on 14 data sets (including maps of land cover, ports, settle-ments, and shipping lanes), information on 800 sites known to be degraded by people, and scientific expertise to model areas where reef degradation is predicted to occur, given existing human pressures on these areas. Results are an indicator of potential threat (risk), not a measure of actual condition. In some places, particularly where good management is practiced, reefs may be at risk but remain relatively healthy. In others, this indicator underestimates the degree to which reefs are threatened and degraded.Our results indicate that:Fifty-eight percent of the world's reefs are poten-tially threatened by human activity -- ranging from coastal development and destructive fishing practices to overexploitation of resources, marine pollution, and runoff from inland deforestation and farming.Coral reefs of Asia (Southeastern); the most species-rich on earth, are the most threatened of any region. More than 80 percent are at risk (undermedium and high potential threat), and over half are at high risk, primarily from coastal development and fishing-related pressures.Overexploitation and coastal development pose the greatest potential threat of the four risk categories considered in this study. Each, individually, affects a third of all reefs.The Pacific, which houses more reef area than any other region, is also the least threatened. About 60 percent of reefs here are at low risk.Outside of the Pacific, 70 percent of all reefs are at risk.At least 11 percent of the world's coral reefs contain high levels of reef fish biodiversity and are under high threat from human activities. These "hot spot" areas include almost all Philippine reefs, and coral communities off the coasts of Asia, the Comoros, and the Lesser Antilles in the Caribbean.Almost half a billion people -- 8 percent of the total global population -- live within 100 kilometers of a coral reef.Globally, more than 400 marine parks, sanctuaries, and reserves (marine protected areas) contain coral reefs. Most of these sites are very small -- more than 150 are under one square kilometer in size. At least 40 countries lack any marine protected areas for conserving their coral reef systems

Differences in intelligence and their relation to position in family

Thesis (Ed.M.)--Boston University This item was digitized by the Internet Archive

Structure and oxidation kinetics of the Si(100)-SiO2 interface

We present first-principles calculations of the structural and electronic properties of Si(001)-SiO2 interfaces. We first arrive at reasonable structures for the c-Si/a-SiO2 interface via a Monte-Carlo simulated annealing applied to an empirical interatomic potential, and then relax these structures using first-principles calculations within the framework of density-functional theory. We find a transition region at the interface, having a thickness on the order of 20\AA, in which there is some oxygen deficiency and a corresponding presence of sub-oxide Si species (mostly Si^+2 and Si^+3). Distributions of bond lengths and bond angles, and the nature of the electronic states at the interface, are investigated and discussed. The behavior of atomic oxygen in a-SiO2 is also investigated. The peroxyl linkage configuration is found to be lower in energy than interstitial or threefold configurations. Based on these results, we suggest a possible mechanism for oxygen diffusion in a-SiO2 that may be relevant to the oxidation process.Comment: 7 pages, two-column style with 6 postscript figures embedded. Uses REVTEX and epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/index.html#ng_sio