4,510 research outputs found
Spreading gossip in social networks
We study a simple model of information propagation in social networks, where
two quantities are introduced: the spread factor, which measures the average
maximal fraction of neighbors of a given node that interchange information
among each other, and the spreading time needed for the information to reach
such fraction of nodes. When the information refers to a particular node at
which both quantities are measured, the model can be taken as a model for
gossip propagation. In this context, we apply the model to real empirical
networks of social acquaintances and compare the underlying spreading dynamics
with different types of scale-free and small-world networks. We find that the
number of friendship connections strongly influences the probability of being
gossiped. Finally, we discuss how the spread factor is able to be applied to
other situations.Comment: 10 pages, 16 figures, Revtex; Virt.J. of Biol. Phys., Oct.1 200
Networking Effects on Cooperation in Evolutionary Snowdrift Game
The effects of networking on the extent of cooperation emerging in a
competitive setting are studied. The evolutionary snowdrift game, which
represents a realistic alternative to the well-known Prisoner's Dilemma, is
studied in the Watts-Strogatz network that spans the regular, small-world, and
random networks through random re-wiring. Over a wide range of payoffs, a
re-wired network is found to suppress cooperation when compared with a
well-mixed or fully connected system. Two extinction payoffs, that characterize
the emergence of a homogeneous steady state, are identified. It is found that,
unlike in the Prisoner's Dilemma, the standard deviation of the degree
distribution is the dominant network property that governs the extinction
payoffs.Comment: Changed conten
Dynamics of Bulk vs. Nanoscale WS_2: Local Strain and Charging Effects
We measured the infrared vibrational properties of bulk and nanoparticle
WS in order to investigate the structure-property relations in these novel
materials. In addition to the symmetry-breaking effects of local strain,
nanoparticle curvature modifies the local charging environment of the bulk
material. Performing a charge analysis on the \emph{xy}-polarized E
vibrational mode, we find an approximate 1.5:1 intralayer charge difference
between the layered 2H material and inorganic fullerene-like (IF)
nanoparticles. This effective charge difference may impact the solid-state
lubrication properties of nanoscale metal dichalcogenides.Comment: 6 pages, 5 figure
Disgust implicated in obsessive-compulsive disorder
Psychiatric classificatory systems consider obsessions and compulsions as forms of anxiety disorder. However, the neurology of diseases associated with obsessive-compulsive symptoms suggests the involvement of fronto-striatal regions likely to be involved in the mediation of the emotion of disgust, suggesting that dysfunctions of disgust should be considered alongside anxiety in the pathogenesis of obsessive-compulsive behaviours. We therefore tested recognition of facial expressions of basic emotions (including disgust) by groups of participants with obsessive-compulsive disorder (OCD) and with Gilles de la Tourette's syndrome (GTS) with and without co-present obsessive-compulsive behaviours (GTS with OCB; GTS without OCB). A group of people suffering from panic disorder and generalized anxiety were also included in the study. Both groups with obsessive-compulsive symptoms (OCD; GTS with OCB) showed impaired recognition of facial expressions of disgust. Such problems were not evident in participants with panic disorder and generalized anxiety, or for participants with GTS without obsessions or compulsions, indicating that the deficit is closely related to the presence of obsessive-compulsive symptoms. Participants with OCD were able to assign words to emotion categories without difficulty, showing that their problem with disgust is linked to a failure to recognize this emotion in others and not a comprehension or response criterion effect. Impaired recognition of disgust is consistent with the neurology of OCD and with the idea that abnormal experience of disgust may be involved in the genesis of obsessions and compulsions
Housework by Husbands Determinants and Implications
WOMEN continue to carry disproportionate responsibility for household tasks. A study of 650 Detroit women reveals that attitudes, employment status, life cycle, and husband's income all contribute to husband's housework effort. Some evidence is presented that the greater the earnings differential of husband over wife, the less he contributes in help at home.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67012/2/10.1177_0192513X8100200207.pd
The Specter of Malpractice: When Law Firm General Counsel and Risk Management Professionals Are Confronted with Potential Malpractice Claims and Ethics Violations
Every day, law firm general counsel and other law firm risk management professionals face a very practical, very vexing problem. The problem is what to do when hearing that a serious ethical mistake or impropriety may have occurred—but without any concrete confirmation that something problematic has, in fact, happened. This essay discusses the most important initial steps and questions that the firm’s general counsel or other risk management professional must address in this confounding situation where the “specter of malpractice” is present. We call this the “specter of malpractice” because a malpractice claim has not yet fully materialized (and it is not entirely clear that one will materialize), but enough risk factors have surfaced to capture the risk management team’s attention. Included among these important and difficult questions are: Could this type of mistake constitute an ethics violation or a future malpractice claim? What duty does a firm’s general counsel or risk management professional have to investigate the situation? What action is required with respect to the firm’s legal malpractice insurer and when should the law firm take that action? What action is required with respect to the law firm’s clients and when should the law firm take that action?
We answer these questions in our short (under 5,000 words) essay, reminding our readers that “an ounce of prevention is worth a pound of cure.
Network dynamics of ongoing social relationships
Many recent large-scale studies of interaction networks have focused on
networks of accumulated contacts. In this paper we explore social networks of
ongoing relationships with an emphasis on dynamical aspects. We find a
distribution of response times (times between consecutive contacts of different
direction between two actors) that has a power-law shape over a large range. We
also argue that the distribution of relationship duration (the time between the
first and last contacts between actors) is exponentially decaying. Methods to
reanalyze the data to compensate for the finite sampling time are proposed. We
find that the degree distribution for networks of ongoing contacts fits better
to a power-law than the degree distribution of the network of accumulated
contacts do. We see that the clustering and assortative mixing coefficients are
of the same order for networks of ongoing and accumulated contacts, and that
the structural fluctuations of the former are rather large.Comment: to appear in Europhys. Let
Prisoner's Dilemma cellular automata revisited: evolution of cooperation under environmental pressure
We propose an extension of the evolutionary Prisoner's Dilemma cellular
automata, introduced by Nowak and May \cite{nm92}, in which the pressure of the
environment is taken into account. This is implemented by requiring that
individuals need to collect a minimum score , representing
indispensable resources (nutrients, energy, money, etc.) to prosper in this
environment. So the agents, instead of evolving just by adopting the behaviour
of the most successful neighbour (who got ), also take into account if
is above or below the threshold . If an
individual has a probability of adopting the opposite behaviour from the one
used by its most successful neighbour. This modification allows the evolution
of cooperation for payoffs for which defection was the rule (as it happens, for
example, when the sucker's payoff is much worse than the punishment for mutual
defection). We also analyse a more sophisticated version of this model in which
the selective rule is supplemented with a "win-stay, lose-shift" criterion. The
cluster structure is analyzed and, for this more complex version we found
power-law scaling for a restricted region in the parameter space.Comment: 15 pages, 8 figures; added figures and revised tex
Growing Scale-Free Networks with Tunable Clustering
We extend the standard scale-free network model to include a ``triad
formation step''. We analyze the geometric properties of networks generated by
this algorithm both analytically and by numerical calculations, and find that
our model possesses the same characteristics as the standard scale-free
networks like the power-law degree distribution and the small average geodesic
length, but with the high-clustering at the same time. In our model, the
clustering coefficient is also shown to be tunable simply by changing a control
parameter - the average number of triad formation trials per time step.Comment: Accepted for publication in Phys. Rev.
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