102 research outputs found
Lorentz breaking Effective Field Theory and observational tests
Analogue models of gravity have provided an experimentally realizable test
field for our ideas on quantum field theory in curved spacetimes but they have
also inspired the investigation of possible departures from exact Lorentz
invariance at microscopic scales. In this role they have joined, and sometime
anticipated, several quantum gravity models characterized by Lorentz breaking
phenomenology. A crucial difference between these speculations and other ones
associated to quantum gravity scenarios, is the possibility to carry out
observational and experimental tests which have nowadays led to a broad range
of constraints on departures from Lorentz invariance. We shall review here the
effective field theory approach to Lorentz breaking in the matter sector,
present the constraints provided by the available observations and finally
discuss the implications of the persisting uncertainty on the composition of
the ultra high energy cosmic rays for the constraints on the higher order,
analogue gravity inspired, Lorentz violations.Comment: 47 pages, 4 figures. Lecture Notes for the IX SIGRAV School on
"Analogue Gravity", Como (Italy), May 2011. V.3. Typo corrected, references
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Inflation from non-minimally coupled scalar field in loop quantum cosmology
The FRW model with non-minimally coupled massive scalar field has been
investigated in LQC framework. Considered form of the potential and coupling
allows applications to Higgs driven inflation. Out of two frames used in the
literature to describe such systems: Jordan and Einstein frame, the latter one
is applied. Specifically, we explore the idea of the Einstein frame being the
natural 'environment' for quantization and the Jordan picture having an
emergent nature. The resulting dynamics qualitatively modifies the standard
bounce paradigm in LQC in two ways: (i) the bounce point is no longer marked by
critical matter energy density, (ii) the Planck scale physics features the
'mexican hat' trajectory with two consecutive bounces and rapid expansion and
recollapse between them. Furthermore, for physically viable coupling strength
and initial data the subsequent inflation exceeds 60 e-foldings.Comment: Clarity improved. Replaced with revised version accepted in JCA
Impacts of meeting minimum access on critical earth systems amidst the Great Inequality
The Sustainable Development Goals aim to improve access to resources and services, reduce environmental degradation, eradicate poverty and reduce inequality. However, the magnitude of the environmental burden that would arise from meeting the needs of the poorest is under debateâespecially when compared to much larger burdens from the rich. We show that the âGreat Accelerationâ of human impacts was characterized by a âGreat Inequalityâ in using and damaging the environment. We then operationalize âjust accessâ to minimum energy, water, food and infrastructure. We show that achieving just access in 2018, with existing inequalities, technologies and behaviours, would have produced 2â26% additional impacts on the Earthâs natural systems of climate, water, land and nutrientsâthus further crossing planetary boundaries. These hypothetical impacts, caused by about a third of humanity, equalled those caused by the wealthiest 1â4%. Technological and behavioural changes thus far, while important, did not deliver just access within a stable Earth system. Achieving these goals therefore calls for a radical redistribution of resources
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Track A Basic Science
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd
Involking silvern voices in healthcare : transforming practice by engaging older adults in collaborative partnerships
Canada's population is aging. This growing trend will ultimately have an impact on nursing practice as older individuals continue to seek healthcare services. Nurses must be able to work in collaboration with the older population to provide quality care. This action research study explored participative healthcare from an older adult's perspective.
This study revealed that older adults prefer to be active participants in their care. The major theme that emerged was true partnership. Three sub-themes that emerged were communication, respect, and trust. These three sub-themes work in unity to contribute to a healthcare experience that exemplifies true partnerships. This study proposes a definition of true partnership as being open to and inviting mutual communication in an atmosphere that encourages equity sharing of information contributing to respect and the development of trust that results in confident collaboration in care
Dynamic Yield Strength of a Zirconium Base Metallic Glass
Taylor anvil tests in the reverse ballistic mode have been carried out to determine the dynamic yield strength of a Zr 62.6 w/o Cu 13.23, Ti 11.01, Ni 9.77, and Be 3.38 metallic glass. Scanning electron microscopy has been utilized to evaluate the details of the rod and anvil interface after impact. Computer simulations have also been carried out to interpret and confirm the results and conclusions.Le test de TAYLOR par la méthode de balistique inverse a été utilisé pour déterminer la résistance dynamique d'un verre métallique de Zr 62.6%-Cu 13.23%-Ti 11.01%-Ni 9.77% et Be 3.38%. La microscopie électronique à balayage a été utilisée pour examiner l'interface entre la cible et le barreau aprÚs impact. Des simulations numériques ont été effectuées pour interpréter et confirmer les résultats et les conclusions
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