38 research outputs found
Large extra dimension effects in Higgs boson production at linear colliders and Higgs factories
In the framework of quantum gravity propagating in large extra dimensions,
the effects of virtual Kaluza-Klein graviton and graviscalar interference with
Higgs boson production amplitudes are computed at linear colliders and Higgs
factories. The interference of the almost-continuous spectrum of the KK
gravitons with the standard model resonant amplitude is finite and predictable
in terms of the fundamental D-dimensional Plank scale M_D and the number of
extra dimensions \delta. We find that, for M_D ~ 1 TeV and \delta=2, effects of
the order of a few percent could be detected for heavy Higgs bosons (m_H>500
GeV) in Higgs production both via WW fusion in e^+e^- colliders and at
\mu^+\mu^- Higgs-boson factories.Comment: 16 pages, 2 figures ; a few comments and references added ; version
to appear in JHE
Quintessence from Shape Moduli
We show that shape moduli in sub-millimeter extra dimensional scenarios,
addressing the gauge hierarchy problem, can dominate the energy density of the
universe today. In our scenario, the volume of the extra dimensions is
stabilized at a sufficiently high scale to avoid conflicts with nucleosynthesis
and solar-system precision gravity experiments, while the shape moduli remain
light but couple extremely weakly to brane-localized matter and easily avoid
these bounds. Nonlocal effects in the bulk of the extra dimension generate a
potential for the shape moduli. The potential has the right form and order of
magnitude to account for the present day cosmic acceleration, in a way
analogous to models of quintessence as a pseudo Nambu-Goldstone boson.Comment: 8 pages, 1 figur
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A multilevel neo-institutional analysis of infection prevention and control in English hospitals: coerced safety culture change?
Despite committed policy, regulative and professional efforts on healthcare safety, little is known about how such macro-interventions permeate organisations and shape culture over time. Informed by neo-institutional theory, we examined how inter-organisational influences shaped safety practices and inter-subjective meanings following efforts for coerced culture change. We traced macro-influences from 2000 to 2015 in infection prevention and control (IPC). Safety perceptions and meanings were inductively analysed from 130 in-depth qualitative interviews with senior- and middle-level managers from 30 English hospitals. A total of 869 institutional interventions were identified; 69% had a regulative component. In this context of forced implementation of safety practices, staff experienced inherent tensions concerning the scope of safety, their ability to be open and prioritisation of external mandates over local need. These tensions stemmed from conflicts among three co-existing institutional logics prevalent in the NHS. In response to requests for change, staff flexibly drew from a repertoire of cognitive, material and symbolic resources within and outside their organisations. They crafted 'strategies of action', guided by a situated assessment of first-hand practice experiences complementing collective evaluations of interventions such as 'pragmatic', 'sensible' and also 'legitimate'. Macro-institutional forces exerted influence either directly on individuals or indirectly by enriching the organisational cultural repertoire
N-body simulations of gravitational dynamics
We describe the astrophysical and numerical basis of N-body simulations, both
of collisional stellar systems (dense star clusters and galactic centres) and
collisionless stellar dynamics (galaxies and large-scale structure). We explain
and discuss the state-of-the-art algorithms used for these quite different
regimes, attempt to give a fair critique, and point out possible directions of
future improvement and development. We briefly touch upon the history of N-body
simulations and their most important results.Comment: invited review (28 pages), to appear in European Physics Journal Plu
NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics
Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset
Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)
[no abstract available
Review of business of the Outer House of the Court of Session
SIGLEAvailable from British Library Document Supply Centre- DSC:GPC/08166 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
The Southall and Ladbroke Grove Joint Inquiry into train protection systems
SIGLEAvailable from British Library Document Supply Centre-DSC:m01/20093 / BLDSC - British Library Document Supply CentreGBUnited Kingdo