4,088 research outputs found
Direct, physically-motivated derivation of the contagion condition for spreading processes on generalized random networks
For a broad range single-seed contagion processes acting on generalized
random networks, we derive a unifying analytic expression for the possibility
of global spreading events in a straightforward, physically intuitive fashion.
Our reasoning lays bare a direct mechanical understanding of an archetypal
spreading phenomena that is not evident in circuitous extant mathematical
approaches.Comment: 4 pages, 1 figure, 1 tabl
Exact solutions for social and biological contagion models on mixed directed and undirected, degree-correlated random networks
We derive analytic expressions for the possibility, probability, and expected
size of global spreading events starting from a single infected seed for a
broad collection of contagion processes acting on random networks with both
directed and undirected edges and arbitrary degree-degree correlations. Our
work extends previous theoretical developments for the undirected case, and we
provide numerical support for our findings by investigating an example class of
networks for which we are able to obtain closed-form expressions.Comment: 10 pages, 3 figure
Harvesting quality hay
R-624; FORAGE QUALITY - The characteristics of a forage
which when fed to livestock will produce high yields of animal products. It is often referred to as nutritive value or feed value
Recommended from our members
Microwave Heating of Lunar Simulants JSC-1A and NU-LHT-3M: Experimental And Theoretical Analysis
Ferromagnetically coupled dimers on the distorted Shastry-Sutherland lattice: Application to (CuCl)LaNb2O7
A recent study [Tassel {\it et al.}, Phys. Rev. Lett. {\bf 105}, 167205
(2010)] has proposed a remarkable spin model for (CuCl)LaNb2O7, in which dimers
are ferromagnetically coupled to each other on the distorted Shastry-Sutherland
lattice. In this model, the intra-dimer exchange coupling J>0 is
antiferromagnetic, while the inter-dimer exchange couplings are ferromagnetic
and take different values, J_x,J_y<0, in the two bond directions. Anticipating
that the highly frustrated character of this model may lead to a wide range of
behaviors in (CuCl)LaNb2O7 and related compounds, we theoretically investigate
the ground state phase diagram of this model in detail using the following
three approaches: a strong-coupling expansion for small J_x and J_y, exact
diagonalization for finite clusters, and a Schwinger boson mean field theory.
When |J_x|, |J_y| <~ J, the system stays in a dimer singlet phase with a finite
spin gap. This state is adiabatically connected to the decoupled-dimer limit
J_x=J_y=0. We show that the magnetization process of this phase depends
crucially on the spatial anisotropy of the inter-dimer couplings. The
magnetization shows a jump or a smooth increase for weak and strong anisotropy,
respectively, after the spin gap closes at a certain magnetic field. When |J_x|
or |J_y| >~ J, quantum phase transitions to various magnetically ordered phases
(ferromagnetic, collinear stripe, and spiral) occur. The Schwinger boson
analysis demonstrates that quantum fluctuations split the classical degeneracy
of different spiral ground states. Implications for (CuCl)LaNb2O7 and related
compounds are discussed in light of our theoretical results and existing
experimental data.Comment: 21 pages, 20 figure
Slightly generalized Generalized Contagion: Unifying simple models of biological and social spreading
We motivate and explore the basic features of generalized contagion, a model
mechanism that unifies fundamental models of biological and social contagion.
Generalized contagion builds on the elementary observation that spreading and
contagion of all kinds involve some form of system memory. We discuss the three
main classes of systems that generalized contagion affords, resembling: simple
biological contagion; critical mass contagion of social phenomena; and an
intermediate, and explosive, vanishing critical mass contagion. We also present
a simple explanation of the global spreading condition in the context of a
small seed of infected individuals.Comment: 8 pages, 5 figures; chapter to appear in "Spreading Dynamics in
Social Systems"; Eds. Sune Lehmann and Yong-Yeol Ahn, Springer Natur
Recommended from our members
mHealth: providing a mindfulness app for women with chronic pelvic pain in gynaecology outpatient clinics: qualitative data analysis of user experience and lessons learnt
OBJECTIVES: To determine whether a pre-existing smartphone app to teach mindfulness meditation is acceptable to women with chronic pelvic pain (CPP) and can be integrated into clinical practice within the National Health Service (NHS) CPP pathways, and to inform the design of a potential randomised clinical trial.
DESIGN: A prestudy patient and public involvement (PPI) group to collect feedback on the acceptability of the existing app and study design was followed by a three-arm randomised feasibility trial. In addition, we undertook interviews and focus groups with patients and staff to explore app usability and acceptability. We also obtained participant comments on the research process, such as acceptability of the study questionnaires.
SETTING: Two gynaecology clinics within Barts Health NHS, London, UK.
PARTICIPANTS: Patients with CPP lasting ā„6 months with access to smartphone or personal computer and understanding of basic English.
INTERVENTION: The intervention was mindfulness meditation content plus additional pain module delivered by a smartphone app. Active controls received muscle relaxation content from the same app. Passive (waiting list) controls received usual care.
MAIN OUTCOME MEASURES: Themes on user feedback, app usability and integration, and reasons for using/not using the app.
RESULTS: The use of the app was low in both active groups. Patients in the prestudy PPI group, all volunteers, were enthusiastic about the app (convenience, content, portability, flexibility, ease of use). Women contributing to the interview or focus group data (n=14), from a 'real world' clinic (some not regular app users), were less positive, citing as barriers lack of opportunities/motivation to use the app and lack of familiarity and capabilities with technology. Staff (n=7) were concerned about the potential need for extra support for them and for the patients, and considered the app needed organisational backing and peer acceptance.
CONCLUSION: The opinions of prestudy PPI volunteers meeting in their private time may not represent those of patients recruited at a routine clinic appointment. It may be more successful to codesign/codevelop an app with typical users than to adapt existing apps for use in real-world clinical populations.
TRIAL REGISTRATION NUMBER: ISRCTN10925965
- ā¦