501 research outputs found
Higher Spin Gravitational Couplings and the Yang--Mills Detour Complex
Gravitational interactions of higher spin fields are generically plagued by
inconsistencies. We present a simple framework that couples higher spins to a
broad class of gravitational backgrounds (including Ricci flat and Einstein)
consistently at the classical level. The model is the simplest example of a
Yang--Mills detour complex, which recently has been applied in the mathematical
setting of conformal geometry. An analysis of asymptotic scattering states
about the trivial field theory vacuum in the simplest version of the theory
yields a rich spectrum marred by negative norm excitations. The result is a
theory of a physical massless graviton, scalar field, and massive vector along
with a degenerate pair of zero norm photon excitations. Coherent states of the
unstable sector of the model do have positive norms, but their evolution is no
longer unitary and their amplitudes grow with time. The model is of
considerable interest for braneworld scenarios and ghost condensation models,
and invariant theory.Comment: 19 pages LaTe
Broadening the Debate About Post-trial Access to Medical Interventions: A Qualitative Study of Participant Experiences at the End of a Trial Investigating a Medical Device to Support Type 1 Diabetes Self-Management.
Increasing ethical attention and debate is focusing on whether individuals who take part in clinical trials should be given access to post-trial care. However, the main focus of this debate has been upon drug trials undertaken in low-income settings. To broaden this debate, we report findings from interviews with individuals (n = 24) who participated in a clinical trial of a closed-loop system, which is a medical device under development for people with type 1 diabetes that automatically adjusts blood glucose to help keep it within clinically recommended ranges. Individuals were recruited from UK sites and interviewed following trial close-out, at which point the closed-loop had been withdrawn. While individuals were stoical and accepting of the requirement to return the closed-loop, they also conveyed varying degrees of distress. Many described having relaxed diabetes management practices while using the closed-loop and having become deskilled as a consequence, which made reverting back to pre-trial regimens challenging. Participants also described unanticipated consequences arising from using a closed-loop. As well as deskilling, these included experiencing psychological and emotional benefits that could not be sustained after the closed-loop had been withdrawn and participants reevaluating their pre- and post-trial life in light of having used a closed-loop and now perceiving this life much more negatively. Participants also voiced frustrations about experiencing better blood glucose control using a closed-loop and then having to revert to using what they now saw as antiquated and imprecise self-management tools. We use these findings to argue that ethical debates about post-trial provisioning need to be broadened to consider potential psychological and emotional harms, and not just clinical harms, that may result from withdrawal of investigated treatments. We also suggest that individuals may benefit from information about potential nonclinical harms to help make informed decisions about trial participation.NIHR, JDR
Prevention is better than cure, but...: Preventive medication as a risk to ordinariness?
Preventive health remains at the forefront of public health concerns; recent initiatives, such as the NHS health check, may lead to recommendations for medication in response to the identification of 'at risk' individuals. Little is known about lay views of preventive medication. This paper uses the case of aspirin as a prophylactic against heart disease to explore views among people invited to screening for a trial investigating the efficacy of such an approach. Qualitative interviews (N=46) and focus groups (N=5, participants 31) revealed dilemmas about preventive medication in the form of clashes between norms: first, in general terms, assumptions about the benefit of prevention were complicated by dislike of medication; second, the individual duty to engage in prevention was complicated by the need not to be over involved with one's own health; third, the potential appeal of this alternative approach to health promotion was complicated by unease about the implications of encouraging irresponsible behaviour among others. Though respondents made different decisions about using the drug, they reported very similar ways of trying to resolve these conflicts, drawing upon concepts of necessity and legitimisation and the special ordinariness of the particular dru
On the cubic interactions of massive and partially-massless higher spins in (A)dS
Cubic interactions of massive and partially-massless totally-symmetric
higher-spin fields in any constant-curvature background of dimension greater
than three are investigated. Making use of the ambient-space formalism, the
consistency condition for the traceless and transverse parts of the
parity-invariant interactions is recast into a system of partial differential
equations. The latter can be explicitly solved for given s_1-s_2-s_3 couplings
and the 2-2-2 and 3-3-2 examples are provided in detail for general choices of
the masses. On the other hand, the general solutions for the interactions
involving massive and massless fields are expressed in a compact form as
generating functions of all the consistent couplings. The St\"uckelberg
formulation of the cubic interactions as well as their massless limits are also
analyzed.Comment: 42 pages, 2 tables, LaTex. Comments on two-derivative couplings
involving partially-massless spin-2 fields added, typos corrected, references
added. v2: final version to appear in JHEP. v3: formulae (3.4) and (3.9)
correcte
Long-Term Functionality of Rural Water Services in Developing Countries: A System Dynamics Approach to Understanding the Dynamic Interaction of Causal Factors
Research has shown that sustainability of rural water infrastructure in developing countries is largely affected by the dynamic and systemic interactions of technical, social, financial, institutional, and environmental factors that can lead to premature water system failure. This research employs systems dynamic modeling, which uses feedback mechanisms to understand how these factors interact dynamically to influence long-term rural water system functionality. To do this, the research first identified and aggregated key factors from literature, then asked water sector experts to indicate the polarity and strength between factors through Delphi and cross impact survey questionnaires, and finally used system dynamics modeling to identify and prioritize feedback mechanisms. The resulting model identified 101 feedback mechanisms that were dominated primarily by three and four-factor loops that contained some combination of the factors: Water System Functionality, Community, Financial, Government, Management, and Technology. These feedback mechanisms were then scored and prioritized, with the most dominant feedback mechanism identified as Water System Functionality – Community – Finance – Management. This research offers insight into the dynamic interaction of factors impacting sustainability of rural water infrastructure through the identification of these feedback mechanisms and makes a compelling case for future research to longitudinally investigate the interaction of these factors in various contexts
Maxwell-like Lagrangians for higher spins
We show how implementing invariance under divergence-free gauge
transformations leads to a remarkably simple Lagrangian description of massless
bosons of any spin. Our construction covers both flat and (A)dS backgrounds and
extends to tensors of arbitrary mixed-symmetry type. Irreducible and traceless
fields produce single-particle actions, while whenever trace constraints can be
dispensed with the resulting Lagrangians display the same reducible,
multi-particle spectra as those emerging from the tensionless limit of free
open-string field theory. For all explored options the corresponding kinetic
operators take essentially the same form as in the spin-one, Maxwell case.Comment: 77 pages, revised version. Erroneous interpretation and proof of the
gauge-fixing procedure for mixed-symmetry fields corrected. As a consequence,
the mixed-symmetry, one-particle Lagrangians are to be complemented with
conditions on the divergences of the fields; all other conclusions unchanged.
Additional minor changes including references added. To appear in JHE
Systematics of 2+ states in C isotopes from the ab initio no-core shell model
We study low-lying states of even carbon isotopes in the range A = 10 - 20
within the large- scale no-core shell model (NCSM). Using several accurate
nucleon-nucleon (NN) as well as NN plus three-nucleon (NNN) interactions, we
calculate excitation energies of the lowest 2+ state, the electromagnetic B(E2;
2+1 -> 0+1) transition rates, the 2+1 quadrupole moments as well as se- lected
electromagnetic transitions among other states. Recent experimental campaigns
to measure 2+-state lifetimes indicate an interesting evolution of nuclear
structure that pose a challenge to reproduce theoretically from first
principles. Our calculations do not include any effective charges or other
fitting parameters. However, calculated results extrapolated to infinite model
spaces are also presented. The model-dependence of those results is discussed.
Overall, we find a good agree- ment with the experimentally observed trends,
although our extrapolated B(E2; 2+1 -> 0+1) value for 16C is lower compared to
the most recent measurements. Relative transition strengths from higher excited
states are investigated and the influence of NNN forces is discussed. In
particular for 16C we find a remarkable sensitivity of the transition rates
from higher excited states to the details of the nuclear interactions.Comment: 22 pages, 8 figures, preprint version. Accepted for publication in
Journal of Physics G: Nuclear and Particle Physic
Higher spin interactions with scalar matter on constant curvature spacetimes: conserved current and cubic coupling generating functions
Cubic couplings between a complex scalar field and a tower of symmetric
tensor gauge fields of all ranks are investigated on any constant curvature
spacetime of dimension d>2. Following Noether's method, the gauge fields
interact with the scalar field via minimal coupling to the conserved currents.
A symmetric conserved current, bilinear in the scalar field and containing up
to r derivatives, is obtained for any rank r from its flat spacetime
counterpart in dimension d+1, via a radial dimensional reduction valid
precisely for the mass-square domain of unitarity in (anti) de Sitter spacetime
of dimension d. The infinite collection of conserved currents and cubic
vertices are summarized in a compact form by making use of generating functions
and of the Weyl/Wigner quantization on constant curvature spaces.Comment: 35+1 pages, v2: two references added, typos corrected, enlarged
discussions in Subsection 5.2 and in Conclusion, to appear in JHE
Returning genome sequences to research participants:Policy and practice
Despite advances in genomic science stimulating an explosion of literature around returning health-related findings, the possibility of returning entire genome sequences to individual research participants has not been widely considered. Through direct involvement in large-scale translational genomics studies, we have identified a number of logistical challenges that would need to be overcome prior to returning individual genome sequence data, including verifying that the data belong to the requestor and providing appropriate informatics support. In addition, we identify a number of ethico-legal issues that require careful consideration, including returning data to family members, mitigating against unintended consequences, and ensuring appropriate governance. Finally, recognising that there is an opportunity cost to addressing these issues, we make some specific pragmatic suggestions for studies that are considering whether to share individual genomic datasets with individual study participants. If data are shared, research should be undertaken into the personal, familial and societal impact of receiving individual genome sequence data
Adult women and ADHD: on the temporal dimensions of ADHD identities
This paper uses conceptual resources drawn psychosocial process thinking (Stenner, 2017, Brown and Reavey, 2015, Brown and Stenner, 2009) and from G.H. Mead in particular, to contribute to an emerging body of work on the experiences of adult women with ADHD (Singh, 2002, Waite and Ivey, 2009, Quinn and Madhoo, 2014, Horton-Salway and Davies, 2018). It has a particular focus on how ADHD features in the construction of women’s identities and life-stories and it draws upon findings from a qualitative investigation of adult women diagnosed or self-diagnosed with Attention Deficit Hyperactivity Disorder (ADHD). A theoretically informed ‘thematic decomposition’ of 16 depth interviews reveals how complex processes of identity transformation are mediated by the social category of ADHD. Through this process, pasts are reconstructed from the perspective of an ‘emergent’ identity that offers participants the potential for a more enabling and positive future
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