130 research outputs found
Structure of a large social network
We study a social network consisting of over individuals, with a
degree distribution exhibiting two power scaling regimes separated by a
critical degree , and a power law relation between degree and
local clustering. We introduce a growing random model based on a local
interaction mechanism that reproduces all of the observed scaling features and
their exponents. Our results lend strong support to the idea that several very
different networks are simultenously present in the human social network, and
these need to be taken into account for successful modeling.Comment: 5 pages, 5 figure
The physics of spreading processes in multilayer networks
The study of networks plays a crucial role in investigating the structure,
dynamics, and function of a wide variety of complex systems in myriad
disciplines. Despite the success of traditional network analysis, standard
networks provide a limited representation of complex systems, which often
include different types of relationships (i.e., "multiplexity") among their
constituent components and/or multiple interacting subsystems. Such structural
complexity has a significant effect on both dynamics and function. Throwing
away or aggregating available structural information can generate misleading
results and be a major obstacle towards attempts to understand complex systems.
The recent "multilayer" approach for modeling networked systems explicitly
allows the incorporation of multiplexity and other features of realistic
systems. On one hand, it allows one to couple different structural
relationships by encoding them in a convenient mathematical object. On the
other hand, it also allows one to couple different dynamical processes on top
of such interconnected structures. The resulting framework plays a crucial role
in helping achieve a thorough, accurate understanding of complex systems. The
study of multilayer networks has also revealed new physical phenomena that
remain hidden when using ordinary graphs, the traditional network
representation. Here we survey progress towards attaining a deeper
understanding of spreading processes on multilayer networks, and we highlight
some of the physical phenomena related to spreading processes that emerge from
multilayer structure.Comment: 25 pages, 4 figure
Mixing patterns and the spread of close-contact infectious diseases
Surprisingly little is known regarding the human mixing patterns relevant to the spread of close-contact infections, such as measles, influenza and meningococcal disease. This study aims to estimate the number of partnerships that individuals make, their stability and the degree to which mixing is assortative with respect to age. We defined four levels of putative at-risk events from casual (physical contact without conversation) to intimate (contact of a sexual nature), and asked university student volunteers to record details on those they contacted at these levels on three separate days. We found that intimate contacts are stable over short time periods whereas there was no evidence of repeat casual contacts with the same individuals. The contacts were increasingly assortative as intimacy increased. Such information will aid the development and parameterisation of models of close contact diseases, and may have direct use in outbreak investigations
E-readers and the death of the book: or, new media and the myth of the disappearing medium
The recent emergence of e-readers and e-books has b
rought the death of the book to the centre of
current debates on new media. In this article, we a
nalyse alternative narratives that surround the
possibility of the disappearance of print books, do
minated by fetishism, fears about the end of
humanism, and ideas of techno-fundamentalist progre
ss. We argue that, in order to comprehend
such narratives, we need to inscribe them in the br
oader history of media. The emergence of new
media, in fact, has often been accompanied by narra
tives about the possible disappearance of
older media: the introduction of television, for in
stance, inspired claims about the forthcoming
death of film and radio. As a recurrent narrative s
haping the reception of media innovation, the
myth of the disappearing medium helps us to make se
nse of the transformations that media
change provokes in our everyday life
A Biased Review of Sociophysics
Various aspects of recent sociophysics research are shortly reviewed:
Schelling model as an example for lack of interdisciplinary cooperation,
opinion dynamics, combat, and citation statistics as an example for strong
interdisciplinarity.Comment: 16 pages for J. Stat. Phys. including 2 figures and numerous
reference
Controlling the net: European approaches to content and access regulation
This article has been accepted for publication in the journal, Journal of Information Science [© CILIP] and the final (edited, revised and typeset) version of this paper will be published in Journal of Information Science, by SAGE Publications Ltd, All rights reserved. © CILIP. For more information please visit: http://jis.sagepub.co.uk
Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.
BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700
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