12,044 research outputs found
Some Thoughts on Terminology and Discipline in Design
In this speculative paper, I will argue that the design community should attempt to develop a “dictionary” of the language of design, along the same lines as the Oxford English Dictionary was and is developed: as a catalogue of the living use of terms. I will sketch an outline of how such a project could be started quite easily with modern technologies. I will then consider one word in particular – “discipline” – as an example of the need for such a dictionary, by examining the various senses of the word and how even just reflecting on that can illuminate issues of clear communications.
Keywords:
Terminology; Lexicography; Semantics; Dictionary; Communication; Language.</p
Experimental effects on dynamics and thermodynamics in nuclear reactions on the symmetry energy as seen by the CHIMERA 4 detector
Heavy ion collisions have been widely used in the last decade to constraint
the parameterizations of the symmetry energy term of nuclear equation of state
(EOS) for asymmetric nuclear matter as a function of baryonic density. In the
Fermi energy domain one is faced with variations of the density within a narrow
range of values around the saturation density =0.16 fm down
towards sub-saturation densities. The experimental observables which are
sensitive to the symmetry energy are constructed starting from the detected
light particles, clusters and heavy fragments that, in heavy ion collisions,
are generally produced by different emission mechanisms at different stages and
time scales of the reaction. In this review the effects of dynamics and
thermodynamics on the symmetry energy in nuclear reactions are discussed and
characterized using an overview of the data taken so far with the CHIMERA
multi-detector array.Comment: 21 pages, 25 figures. Review to appear in EPJA special volume on
nuclear symmetry energ
Coalescent histories for lodgepole species trees
Coalescent histories are combinatorial structures that describe for a given
gene tree and species tree the possible lists of branches of the species tree
on which the gene tree coalescences take place. Properties of the number of
coalescent histories for gene trees and species trees affect a variety of
probabilistic calculations in mathematical phylogenetics. Exact and asymptotic
evaluations of the number of coalescent histories, however, are known only in a
limited number of cases. Here we introduce a particular family of species
trees, the \emph{lodgepole} species trees , in which
tree has taxa. We determine the number of coalescent
histories for the lodgepole species trees, in the case that the gene tree
matches the species tree, showing that this number grows with in the
number of taxa . This computation demonstrates the existence of tree
families in which the growth in the number of coalescent histories is faster
than exponential. Further, it provides a substantial improvement on the lower
bound for the ratio of the largest number of matching coalescent histories to
the smallest number of matching coalescent histories for trees with taxa,
increasing a previous bound of
to . We discuss the implications of our
enumerative results for phylogenetic computations
On the number of ranked species trees producing anomalous ranked gene trees
Analysis of probability distributions conditional on species trees has
demonstrated the existence of anomalous ranked gene trees (ARGTs), ranked gene
trees that are more probable than the ranked gene tree that accords with the
ranked species tree. Here, to improve the characterization of ARGTs, we study
enumerative and probabilistic properties of two classes of ranked labeled
species trees, focusing on the presence or avoidance of certain subtree
patterns associated with the production of ARGTs. We provide exact enumerations
and asymptotic estimates for cardinalities of these sets of trees, showing that
as the number of species increases without bound, the fraction of all ranked
labeled species trees that are ARGT-producing approaches 1. This result extends
beyond earlier existence results to provide a probabilistic claim about the
frequency of ARGTs
Universal quantum magnetometry with spin states at equilibrium
We address metrological protocols for the estimation of the intensity and the
orientation of a magnetic field, and show that quantum-enhanced precision may
be achieved by probing the field with an arbitrary spin at thermal equilibrium.
We derive a general expression for the ultimate achievable precision, as given
by the quantum Fisher information, and express this quantity in terms of common
thermodynamic quantities. We also seek for the optimal observable, and show
that it corresponds to the spin projection along a suitable direction, defined
by a universal function of the spin temperature. Finally, we prove the
robustness of our scheme against deviations of the measured spin projection
from optimality.Comment: Phys. Rev. Lett., in pres
Fast filtering and animation of large dynamic networks
Detecting and visualizing what are the most relevant changes in an evolving
network is an open challenge in several domains. We present a fast algorithm
that filters subsets of the strongest nodes and edges representing an evolving
weighted graph and visualize it by either creating a movie, or by streaming it
to an interactive network visualization tool. The algorithm is an approximation
of exponential sliding time-window that scales linearly with the number of
interactions. We compare the algorithm against rectangular and exponential
sliding time-window methods. Our network filtering algorithm: i) captures
persistent trends in the structure of dynamic weighted networks, ii) smoothens
transitions between the snapshots of dynamic network, and iii) uses limited
memory and processor time. The algorithm is publicly available as open-source
software.Comment: 6 figures, 2 table
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