2,280 research outputs found
Combinatorics of simple marked mesh patterns in 132-avoiding permutations
We present some combinatorial interpretations for coefficients appearing in
series partitioning the permutations avoiding 132 along marked mesh patterns.
We identify for patterns in which only one parameter is non zero the
combinatorial family in bijection with 132-avoiding permutations and also
preserving the statistic counted by the marked mesh pattern.Comment: 11 pages, 6 figures, submitted at FPSAC 201
Lamb Shift in Light Muonic Atoms - Revisited
In connection with recent and proposed experiments, and new theoretical
results, my previous calculations of the Lamb shift in muonic hydrogen will be
reviewed and compared with other work. In addition, numerical results for
muonic deuterium and helium will be presented. Some previously neglected (but
very small) effects are included.Comment: 41 pages. This paper has appeared in Annals of Physics, vol. 327, pp
733-763 (2012). The present version has corrected several misprints, and
updated some references to take into account new result
Deformed diagonal harmonic polynomials for complex reflection groups
We introduce deformations of the space of (multi-diagonal) harmonic
polynomials for any finite complex reflection group of the form W=G(m,p,n), and
give supporting evidence that this space seems to always be isomorphic, as a
graded W-module, to the undeformed version.Comment: 11 pages, 1 figur
Lamb Shift in Muonic Hydrogen
The Lamb shift in muonic hydrogen continues to be a subject of experimental
and theoretical investigation. Here my older work on the subject is updated to
provide a complementary calculation of the energies of the 2p-2s transitions in
muonic hydrogen.Comment: 15 pages, no figures. 2 small misprints corrected. Published in Phys.
Rev.
Geometrically enhanced closed-loop multi-turn sensor devices that enable reliable magnetic domain wall motion
We experimentally realize a sophisticated structure geometry for reliable
magnetic domain wall-based multi-turn-counting sensor devices, which we term
closed-loop devices that can sense millions of turns. The concept relies on the
reliable propagation of domain walls through a cross-shaped intersection of
magnetic conduits, to allow the intertwining of loops of the sensor device. As
a key step to reach the necessary reliability of the operation, we develop a
combination of tilted wires called the syphon structure at the entrances of the
cross. We measure the control and reliability of the domain wall propagation
individually for cross-shaped intersections, the syphon geometries and finally
combinations of the two for various field configurations (strengths and
angles). The various measured syphon geometries yield a dependence of the
domain wall propagation on the shape that we explain by the effectively acting
transverse and longitudinal external applied magnetic fields. The combination
of both elements yields a behaviour that cannot be explained by a simple
superposition of the individual different maximum field operation values. We
identify as an additional process the nucleation of domain walls in the cross,
which then allows us to fully gauge the operational parameters. Finally, we
demonstrate that by tuning the central dimensions of the cross and choosing the
optimum angle for the syphon structure reliable sensor operation is achieved,
which paves the way for disruptive multi-turn sensor devices
MEDIUM TO LONG TERM IMPACTS ON FORMER PARTICIPANTS OF THE SHOULDER TO SHOULDER GLOBAL BRIGADES TO ECUADOR
Medium to Long Term Impacts on Former Participants of the Shoulder to Shoulder Global Brigades to Ecuador. International service learning and voluntourism programs in global health evoke benefits for both community and the intervener. While it is clear that the Shoulder to Shoulder Global program at the University of Kentucky provides a service to an economically resource poor community in Santo Domingo, Ecuador, what is unclear is the impact these interprofessional experiences have on the participants that travel with the four times a year health brigades. This study proposes to answer the question of what are the educational, personal and professional impacts that brigade participants experience. Alumni of the Shoulder to Shoulder Global health brigades from 2007 – 2017 were sent a twenty-three question survey to better understand the impact of this program. Seventy-five responses to the quantitative and qualitative questions were received and a chi square analysis was performed of subgroups within the seventy-five respondents. The findings indicate that this program has positively impacted participants in all three areas, with strong evidence to show that the impacts are related to the initial and intermediate outcomes, with more data needed to better assess the long-term program outcomes
Between Nowhere and Everywhere: The Challenges of Placing the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES)
Global Environmental Assessments (GEAs) have become influential processes in environmental governance, with the objective to gather policy-relevant knowledge on environmental issues for decision-makers. This thesis offers the first ethnographic account of the nascent Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) which, in contrast to earlier GEAs, aims to implement an inclusive model of expertise. Underlying this move are concerns regarding both the effectiveness of GEAs and their democratization. GEAs have also faced numerous criticisms for being dominated by the global North and for failing to consider the diversity of ways of making sense of global environmental change. Drawing on Science and Technology Studies and on the emerging literature on geographies of science, I view science and policy as being mutually entangled, rather than as two separate domains, and conceptualise GEAs as sites of co-production. It is important therefore to study how categories such as ‘science’, ‘policy’, ‘local’ and ‘global’ are produced and to investigate the practices and places through which knowledge is constructed as policy-relevant. I argue that, despite the aspiration to be global institutions that transcend specific national and cultural contexts and interests, GEAs themselves are situated initiatives which produce a ‘view from somewhere’. Using qualitative methods, I examine three processes within IPBES: (1) the choice of location for its Secretariat; (2) the development of its conceptual framework; and (3) the constitution of the Multidisciplinary Expert Panel. Results confirm that IPBES presents a number of innovative features but also reveal significant ambiguities as to whether IPBES is actually ‘opening-up’ its frame of reference and embracing multiple forms of knowledges and expertise. While IPBES aspires to provide the inclusive ‘view from everywhere’, the narrative of science as providing the disinterested ‘view from nowhere’ and the interest-riven context in which it operates undermines its ambitions
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