6,531 research outputs found
Subtraction Menger algebras
Abstract characterizations of Menger algebras of partial -place functions
defined on a set and closed under the set-theoretic difference functions
treatment as subsets of the Cartesian product are given
The relation of semiadjacency of -semigroups of transformations
We consider two relations on a -semigroup of partial functions of a
given set: the inclusion of domains and the semiadjacencity (i.e., the
inclusion of the image of the first function into the domain of the second),
which characterized with an abstract point of view using the elementary system
of axioms, i.e., system conditions, recorded in the language narrow predicate
calculus with equality
Representations of -semigroups by multiplace functions
We describe the representations of -semigroups, i.e. groupoids with
binary associative operations, by partial -place functions and prove
that any such representation is a union of some family of representations
induced by Schein's determining pairs.Comment: 17 page
The Cosmic Censor Forbids Naked Topology
For any asymptotically flat spacetime with a suitable causal structure
obeying (a weak form of) Penrose's cosmic censorship conjecture and satisfying
conditions guaranteeing focusing of complete null geodesics, we prove that
active topological censorship holds. We do not assume global hyperbolicity, and
therefore make no use of Cauchy surfaces and their topology. Instead, we
replace this with two underlying assumptions concerning the causal structure:
that no compact set can signal to arbitrarily small neighbourhoods of spatial
infinity (``-avoidance''), and that no future incomplete null geodesic is
visible from future null infinity. We show that these and the focusing
condition together imply that the domain of outer communications is simply
connected. Furthermore, we prove lemmas which have as a consequence that if a
future incomplete null geodesic were visible from infinity, then given our
-avoidance assumption, it would also be visible from points of spacetime
that can communicate with infinity, and so would signify a true naked
singularity.Comment: To appear in CQG, this improved version contains minor revisions to
incorporate referee's suggestions. Two revised references. Plain TeX, 12
page
Representations of Menger -semigroups by multiplace functions
Investigation of partial multiplace functions by algebraic methods plays an
important role in modern mathematics were we consider various operations on
sets of functions, which are naturally defined. The basic operation for
-place functions is an -ary superposition , but there are some
other naturally defined operations, which are also worth of consideration. In
this paper we consider binary Mann's compositions \op{1},...,\op{n} for
partial -place functions, which have many important applications for the
study of binary and -ary operations. We present methods of representations
of such algebras by -place functions and find an abstract characterization
of the set of -place functions closed with respect to the set-theoretic
inclusion
Learning from error: leading a culture of safety
A recent shift towards more collective leadership in the NHS can help to achievea culture of safety, particularly through encouraging frontline staff to participateand take responsibility for improving safety through learning from error andnear misses. Leaders must ensure that they provide psychological safety,organizational fairness and learning systems for staff to feel confident in raisingconcerns, that they have the autonomy and skills to lead continual improvement,and that they have responsibility for spreading this learning within and acrossorganizations
Biased Information Search in Homogeneous Groups: Confidence as a Moderator for the Effect of Anticipated Task Requirements
When searching for information, groups that are homogeneous regarding their members’ prediscussion decision preferences show a strong bias for information that supports rather than conflicts with the prevailing opinion (confirmation bias). The present research examined whether homogeneous groups blindly search for information confirming their beliefs irrespective of the anticipated task or whether they are sensitive to the usefulness of new information for this forthcoming task. Results of three experiments show that task sensitivity depends on the groups’ confidence in the correctness of their decision: Moderately confident groups displayed a strong confirmation bias when they anticipated having to give reasons for their decision but showed a balanced information search or even a disconfirmation bias (i.e., predominately seeking conflicting information) when they anticipated having to refute unterarguments. In contrast, highly confident groups demonstrated a strong confirmation bias independent of the anticipated task requirements
Etching of random solids: hardening dynamics and self-organized fractality
When a finite volume of an etching solution comes in contact with a
disordered solid, a complex dynamics of the solid-solution interface develops.
Since only the weak parts are corroded, the solid surface hardens
progressively. If the etchant is consumed in the chemical reaction, the
corrosion dynamics slows down and stops spontaneously leaving a fractal solid
surface, which reveals the latent percolation criticality hidden in any random
system. Here we introduce and study, both analytically and numerically, a
simple model for this phenomenon. In this way we obtain a detailed description
of the process in terms of percolation theory. In particular we explain the
mechanism of hardening of the surface and connect it to Gradient Percolation.Comment: Latex, aipproc, 6 pages, 3 figures, Proceedings of 6th Granada
Seminar on Computational Physic
Implementing digital resources for clinicians' and patients' varying needs.
This paper presents an overview of several evidence-based medicine and patient information studies conducted across the UK health service over a 4 year period, investigating clinicians', managers', and patients' perceptions of digital resources (primarily digital libraries) in hospitals, Primary Care Trusts, NHS Direct (patient call centre) and patient groups. In-depth interviews and focus groups are analysed using grounded theory methodologies and through content analysis used to produce quantitative finding. The perceived impacts of three different methods employed for delivering health informatics are presented. The findings highlight some generic issues relevant for health informatics in the UK health sector as well as some specific issues for medical digital libraries. This paper reviews in more detail the issues of medical technology implementation (traditional implementation, on the wards, and intermediaries within in communities). A breakdown of the clinicians' and patients' information journey (information initiation, facilitation and interpretation) is also presented with regard to medical digital libraries and online resources. Broad guidelines derived from these findings are provided for health-informatics deployment
More than a cognitive experience: unfamiliarity, invalidation, and emotion in organizational learning
Literature on organizational learning (OL) lacks an integrative framework that captures the emotions involved as OL proceeds. Drawing on personal construct theory, we suggest that organizations learn where their members reconstrue meaning around questions of strategic significance for the organization. In this 5-year study of an electronics company, we explore the way in which emotions change as members perceive progress or a lack of progress around strategic themes. Our framework also takes into account whether OL involves experiences that are familiar or unfamiliar and the implications for emotions. We detected similar patterns of emotion arising over time for three different themes in our data, thereby adding to OL perspectives that are predominantly cognitive in orientation
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