23,362 research outputs found
Games and literary theory conference, 2013 : conference review
The Department of English of the University of Malta collaborated with the Institute of Digital Games (University of Malta) to hold the First International Conference on Games and Literary Theory. It ran from the 31st of October to the 1st of November 2013, and was held at the Old University Building, Valletta, Malta. The event proved to be an overwhelmingly smooth and positive experience for all involved. One of the eventβs particularly positive aspects was its structure β only one panel at a time with two or three papers each β which admitted fewer papers than is usual for such conferences. In doing so, it gave space for, and indeed generated, a healthy debate after each paper was delivered, allowing both speaker and audience to immerse themselves in the topics at hand.peer-reviewe
A Perspective on Unique Information: Directionality, Intuitions, and Secret Key Agreement
Recently, the partial information decomposition emerged as a promising
framework for identifying the meaningful components of the information
contained in a joint distribution. Its adoption and practical application,
however, have been stymied by the lack of a generally-accepted method of
quantifying its components. Here, we briefly discuss the bivariate (two-source)
partial information decomposition and two implicitly directional
interpretations used to intuitively motivate alternative component definitions.
Drawing parallels with secret key agreement rates from information-theoretic
cryptography, we demonstrate that these intuitions are mutually incompatible
and suggest that this underlies the persistence of competing definitions and
interpretations. Having highlighted this hitherto unacknowledged issue, we
outline several possible solutions.Comment: 5 pages, 3 tables;
http://csc.ucdavis.edu/~cmg/compmech/pubs/pid_intuition.ht
Unique Information via Dependency Constraints
The partial information decomposition (PID) is perhaps the leading proposal
for resolving information shared between a set of sources and a target into
redundant, synergistic, and unique constituents. Unfortunately, the PID
framework has been hindered by a lack of a generally agreed-upon, multivariate
method of quantifying the constituents. Here, we take a step toward rectifying
this by developing a decomposition based on a new method that quantifies unique
information. We first develop a broadly applicable method---the dependency
decomposition---that delineates how statistical dependencies influence the
structure of a joint distribution. The dependency decomposition then allows us
to define a measure of the information about a target that can be uniquely
attributed to a particular source as the least amount which the source-target
statistical dependency can influence the information shared between the sources
and the target. The result is the first measure that satisfies the core axioms
of the PID framework while not satisfying the Blackwell relation, which depends
on a particular interpretation of how the variables are related. This makes a
key step forward to a practical PID.Comment: 15 pages, 7 figures, 2 tables, 3 appendices;
http://csc.ucdavis.edu/~cmg/compmech/pubs/idep.ht
Unique Information and Secret Key Agreement
The partial information decomposition (PID) is a promising framework for
decomposing a joint random variable into the amount of influence each source
variable Xi has on a target variable Y, relative to the other sources. For two
sources, influence breaks down into the information that both X0 and X1
redundantly share with Y, what X0 uniquely shares with Y, what X1 uniquely
shares with Y, and finally what X0 and X1 synergistically share with Y.
Unfortunately, considerable disagreement has arisen as to how these four
components should be quantified. Drawing from cryptography, we consider the
secret key agreement rate as an operational method of quantifying unique
informations. Secret key agreement rate comes in several forms, depending upon
which parties are permitted to communicate. We demonstrate that three of these
four forms are inconsistent with the PID. The remaining form implies certain
interpretations as to the PID's meaning---interpretations not present in PID's
definition but that, we argue, need to be explicit. These reveal an
inconsistency between third-order connected information, two-way secret key
agreement rate, and synergy. Similar difficulties arise with a popular PID
measure in light the results here as well as from a maximum entropy viewpoint.
We close by reviewing the challenges facing the PID.Comment: 9 pages, 3 figures, 4 tables;
http://csc.ucdavis.edu/~cmg/compmech/pubs/pid_skar.htm. arXiv admin note:
text overlap with arXiv:1808.0860
Molecular Model of the Microvillar Cytoskeleton and Organization of the Brush Border
BACKGROUND. Brush border microvilli are ~1-Β΅m long finger-like projections emanating from the apical surfaces of certain, specialized absorptive epithelial cells. A highly symmetric hexagonal array of thousands of these uniformly sized structures form the brush border, which in addition to aiding in nutrient absorption also defends the large surface area against pathogens. Here, we present a molecular model of the protein cytoskeleton responsible for this dramatic cellular morphology. METHODOLOGY/PRINCIPAL FINDINGS. The model is constructed from published crystallographic and microscopic structures reported by several groups over the last 30+ years. Our efforts resulted in a single, unique, self-consistent arrangement of actin, fimbrin, villin, brush border myosin (Myo1A), calmodulin, and brush border spectrin. The central actin core bundle that supports the microvillus is nearly saturated with fimbrin and villin cross-linkers and has a density similar to that found in protein crystals. The proposed model accounts for all major proteinaceous components, reproduces the experimentally determined stoichiometry, and is consistent with the size and morphology of the biological brush border membrane. CONCLUSIONS/SIGNIFICANCE. The model presented here will serve as a structural framework to explain many of the dynamic cellular processes occurring over several time scales, such as protein diffusion, association, and turnover, lipid raft sorting, membrane deformation, cytoskeletal-membrane interactions, and even effacement of the brush border by invading pathogens. In addition, this model provides a structural basis for evaluating the equilibrium processes that result in the uniform size and structure of the highly dynamic microvilli.Boston University (Graduate Student Research Fellowship); National Institutes of Health (GM62886
- β¦