7,823 research outputs found
Towards an expanded model of litigation
Introduction: The call for contributions for this workshop describes the important new challenges for the legal search
community this domain brings. Rather than just understanding the challenges this domain poses in terms of
their technical properties, we would like to suggest that understanding these challenges as socio-technical
challenges will be important. That is, as well as calling for research on a technical level to address these
challenges we are also calling for work to understand the social practices of those involved in e-discovery
(ED) and related legal work. A particularly interesting feature of this field is that it is likely that search
technologies will (at least semi-)automate responsiveness review in the relatively near term and this will
change the way that the work is organised and done in many ways – offering new possibilities for new
ways of organising the work. As well as designing those technologies for automating responsiveness
review we need to be envisioning how the work will be done in the future, how these technologies will
impact the organisation of the case and so on. In this position paper we therefore outline the importance of
understanding the wider social context of ED when designing tools and technologies to support and change
the work. We would like to reinforce and expand on Conrad’s call for IR researchers to understand just
what ED entails [2], include the stages that come both before and after core retrieval activities.
The importance of considering the social aspects of work in the design of the technology has been
established for some time. Ushering in this ‘turn to the social,’ and focusing on interface design, Gentner
and Grudin [4] described how the GUI has already changed from an interface for engineers, representing
the engineering model of the machine to one that supported single ‘everyman’ users (based on ideas from
psychology). From then onwards the interface has evolved to support groups of users, taking into account
the social and organisational contexts of use. This has particular resonance for the design of ED
technologies: during ED in particular and the wider legal process there are often many lawyers involved –
reviewing documents, determining issues, etc. Even if the way that their work is organised currently is not
seen as collaborative in the traditional sense – with individual lawyers working on individual document sets
to review them - their work needs to be coordinated and it seems likely that their work could be enhanced
by, for example, knowledge of what their colleagues had found, how the case was shaping up, new key
terms and facts turned up and so on. Work is often modelled for the purposes of design using process
models, but this misses out on the richness and variety actually found when one examines how the work is
carried out [3]. Technologies which strictly enforce the process models can often hinder the work, or end
up being worked around as was the case with workflow systems since people interpret processes very
flexibly to get the work done ([1], [3]). Other studies in other fields have found similar problems when
systems are designed on for example cognitive models of how the work is done; they often do not take into
account the situated nature of the work and thus they can be very difficult to use [5]. We believe, like [2],
that a clear understanding of the social practices of ED is vital for the creation of high-quality, meaningful
tools and technologies. We furthermore propose that work practice studies, to be used in combination with
other methods, are a central part of getting the detailed understanding of the work practices central to
designing useful and intelligent tools. Work practice studies would involve ethnographies, consisting
primarily of observation, undertaken of practitioners engaging in the work of ED
Effects of supercoiling on enhancer-promoter contacts.
Using Brownian dynamics simulations, we investigate here one of possible roles of supercoiling within topological domains constituting interphase chromosomes of higher eukaryotes. We analysed how supercoiling affects the interaction between enhancers and promoters that are located in the same or in neighbouring topological domains. We show here that enhancer-promoter affinity and supercoiling act synergistically in increasing the fraction of time during which enhancer and promoter stay in contact. This stabilizing effect of supercoiling only acts on enhancers and promoters located in the same topological domain. We propose that the primary role of recently observed supercoiling of topological domains in interphase chromosomes of higher eukaryotes is to assure that enhancers contact almost exclusively their cognate promoters located in the same topological domain and avoid contacts with very similar promoters but located in neighbouring topological domains
Alexander quandle lower bounds for link genera
We denote by Q_F the family of the Alexander quandle structures supported by
finite fields. For every k-component oriented link L, every partition P of L
into h:=|P| sublinks, and every labelling z of such a partition by the natural
numbers z_1,...,z_n, the number of X-colorings of any diagram of (L,z) is a
well-defined invariant of (L,P), of the form q^(a_X(L,P,z)+1) for some natural
number a_X(L,P,z). Letting X and z vary in Q_F and among the labellings of P,
we define a derived invariant A_Q(L,P)=sup a_X(L,P,z).
If P_M is such that |P_M|=k, we show that A_Q(L,P_M) is a lower bound for
t(L), where t(L) is the tunnel number of L. If P is a "boundary partition" of L
and g(L,P) denotes the infimum among the sums of the genera of a system of
disjoint Seifert surfaces for the L_j's, then we show that A_Q(L,P) is at most
2g(L,P)+2k-|P|-1. We set A_Q(L):=A_Q(L,P_m), where |P_m|=1. By elaborating on a
suitable version of a result by Inoue, we show that when L=K is a knot then
A_Q(K) is bounded above by A(K), where A(K) is the breadth of the Alexander
polynomial of K. However, for every g we exhibit examples of genus-g knots
having the same Alexander polynomial but different quandle invariants A_Q.
Moreover, in such examples A_Q provides sharp lower bounds for the genera of
the knots. On the other hand, A_Q(L) can give better lower bounds on the genus
than A(L), when L has at least two components.
We show that in order to compute A_Q(L) it is enough to consider only
colorings with respect to the constant labelling z=1. In the case when L=K is a
knot, if either A_Q(K)=A(K) or A_Q(K) provides a sharp lower bound for the knot
genus, or if A_Q(K)=1, then A_Q(K) can be realized by means of the proper
subfamily of quandles X=(F_p,*), where p varies among the odd prime numbers.Comment: 36 pages; 16 figure
Spatial structures and dynamics of kinetically constrained models for glasses
Kob and Andersen's simple lattice models for the dynamics of structural
glasses are analyzed. Although the particles have only hard core interactions,
the imposed constraint that they cannot move if surrounded by too many others
causes slow dynamics. On Bethe lattices a dynamical transition to a partially
frozen phase occurs. In finite dimensions there exist rare mobile elements that
destroy the transition. At low vacancy density, , the spacing, ,
between mobile elements diverges exponentially or faster in . Within the
mobile elements, the dynamics is intrinsically cooperative and the
characteristic time scale diverges faster than any power of (although
slower than ). The tagged-particle diffusion coefficient vanishes roughly
as .Comment: 4 pages. Accepted for pub. in Phys. Rev. Let
Studies of global and local entanglements of individual protein chains using the concept of knotoids.
We study here global and local entanglements of open protein chains by implementing the concept of knotoids. Knotoids have been introduced in 2012 by Vladimir Turaev as a generalization of knots in 3-dimensional space. More precisely, knotoids are diagrams representing projections of open curves in 3D space, in contrast to knot diagrams which represent projections of closed curves in 3D space. The intrinsic difference with classical knot theory is that the generalization provided by knotoids admits non-trivial topological entanglement of the open curves provided that their geometry is frozen as it is the case for crystallized proteins. Consequently, our approach doesn't require the closure of chains into loops which implies that the geometry of analysed chains does not need to be changed by closure in order to characterize their topology. Our study revealed that the knotoid approach detects protein regions that were classified earlier as knotted and also new, topologically interesting regions that we classify as pre-knotted
Lattice Glass Models
Motivated by the concept of geometrical frustration, we introduce a class of
statistical mechanics lattice models for the glass transition. Monte Carlo
simulations in three dimensions show that they display a dynamical glass
transition which is very similar to that observed in other off-lattice systems
and which does not depend on a specific dynamical rule. Whereas their analytic
solution within the Bethe approximation shows that they do have a discontinuous
glass transition compatible with the numerical observations.Comment: 4 pages, 2 figures; minor change
Transcription-induced supercoiling as the driving force of chromatin loop extrusion during formation of TADs in interphase chromosomes.
Using molecular dynamics simulations, we show here that growing plectonemes resulting from transcription-induced supercoiling have the ability to actively push cohesin rings along chromatin fibres. The pushing direction is such that within each topologically associating domain (TAD) cohesin rings forming handcuffs move from the source of supercoiling, constituted by RNA polymerase with associated DNA topoisomerase TOP1, towards borders of TADs, where supercoiling is released by topoisomerase TOPIIB. Cohesin handcuffs are pushed by continuous flux of supercoiling that is generated by transcription and is then progressively released by action of TOPIIB located at TADs borders. Our model explains what can be the driving force of chromatin loop extrusion and how it can be ensured that loops grow quickly and in a good direction. In addition, the supercoiling-driven loop extrusion mechanism is consistent with earlier explanations proposing why TADs flanked by convergent CTCF binding sites form more stable chromatin loops than TADs flanked by divergent CTCF binding sites. We discuss the role of supercoiling in stimulating enhancer promoter contacts and propose that transcription of eRNA sends the first wave of supercoiling that can activate mRNA transcription in a given TAD
Fractal space-times under the microscope: A Renormalization Group view on Monte Carlo data
The emergence of fractal features in the microscopic structure of space-time
is a common theme in many approaches to quantum gravity. In this work we carry
out a detailed renormalization group study of the spectral dimension and
walk dimension associated with the effective space-times of
asymptotically safe Quantum Einstein Gravity (QEG). We discover three scaling
regimes where these generalized dimensions are approximately constant for an
extended range of length scales: a classical regime where , a
semi-classical regime where , and the UV-fixed point
regime where . On the length scales covered by
three-dimensional Monte Carlo simulations, the resulting spectral dimension is
shown to be in very good agreement with the data. This comparison also provides
a natural explanation for the apparent puzzle between the short distance
behavior of the spectral dimension reported from Causal Dynamical
Triangulations (CDT), Euclidean Dynamical Triangulations (EDT), and Asymptotic
Safety.Comment: 26 pages, 6 figure
(2+1)-Dimensional Quantum Gravity as the Continuum Limit of Causal Dynamical Triangulations
We perform a non-perturbative sum over geometries in a (2+1)-dimensional
quantum gravity model given in terms of Causal Dynamical Triangulations.
Inspired by the concept of triangulations of product type introduced
previously, we impose an additional notion of order on the discrete, causal
geometries. This simplifies the combinatorial problem of counting geometries
just enough to enable us to calculate the transfer matrix between boundary
states labelled by the area of the spatial universe, as well as the
corresponding quantum Hamiltonian of the continuum theory. This is the first
time in dimension larger than two that a Hamiltonian has been derived from such
a model by mainly analytical means, and opens the way for a better
understanding of scaling and renormalization issues.Comment: 38 pages, 13 figure
Tilings, tiling spaces and topology
To understand an aperiodic tiling (or a quasicrystal modeled on an aperiodic
tiling), we construct a space of similar tilings, on which the group of
translations acts naturally. This space is then an (abstract) dynamical system.
Dynamical properties of the space (such as mixing, or the spectrum of the
translation operator) are closely related to bulk properties of the individual
tilings (such as the diffraction pattern). The topology of the space of
tilings, particularly the Cech cohomology, gives information on how the
original tiling can be deformed. Tiling spaces can be constructed as inverse
limits of branched manifolds.Comment: 8 pages, including 2 figures, talk given at ICQ
- …