2,449 research outputs found
Operational experiences and characteristics of the M2-F2 lifting body flight control system
M2-F2 lifting body flight control syste
Open-closed TQFTs extend Khovanov homology from links to tangles
We use a special kind of 2-dimensional extended Topological Quantum Field
Theories (TQFTs), so-called open-closed TQFTs, in order to extend Khovanov
homology from links to arbitrary tangles, not necessarily even. For every plane
diagram of an oriented tangle, we construct a chain complex whose homology is
invariant under Reidemeister moves. The terms of this chain complex are modules
of a suitable algebra A such that there is one action of A or A^op for every
boundary point of the tangle. We give examples of such algebras A for which our
tangle homology theory reduces to the link homology theories of Khovanov, Lee,
and Bar-Natan if it is evaluated for links. As a consequence of the Cardy
condition, Khovanov's graded theory can only be extended to tangles if the
underlying field has finite characteristic. In all cases in which the algebra A
is strongly separable, i.e. for Bar-Natan's theory in any characteristic and
for Lee's theory in characteristic other than 2, we also provide the required
algebraic operation for the composition of oriented tangles. Just as Khovanov's
theory for links can be recovered from Lee's or Bar-Natan's by a suitable
spectral sequence, we provide a spectral sequence in order to compute our
tangle extension of Khovanov's theory from that of Bar-Natan's or Lee's theory.
Thus, we provide a tangle homology theory that is locally computable and still
strong enough to recover characteristic p Khovanov homology for links.Comment: 56 pages, LaTeX2e with xypic and pstricks macro
Polynomial functors and combinatorial Dyson-Schwinger equations
We present a general abstract framework for combinatorial Dyson-Schwinger
equations, in which combinatorial identities are lifted to explicit bijections
of sets, and more generally equivalences of groupoids. Key features of
combinatorial Dyson-Schwinger equations are revealed to follow from general
categorical constructions and universal properties. Rather than beginning with
an equation inside a given Hopf algebra and referring to given Hochschild
-cocycles, our starting point is an abstract fixpoint equation in groupoids,
shown canonically to generate all the algebraic structure. Precisely, for any
finitary polynomial endofunctor defined over groupoids, the system of
combinatorial Dyson-Schwinger equations has a universal solution,
namely the groupoid of -trees. The isoclasses of -trees generate
naturally a Connes-Kreimer-like bialgebra, in which the abstract
Dyson-Schwinger equation can be internalised in terms of canonical
-operators. The solution to this equation is a series (the Green function)
which always enjoys a Fa\`a di Bruno formula, and hence generates a
sub-bialgebra isomorphic to the Fa\`a di Bruno bialgebra. Varying yields
different bialgebras, and cartesian natural transformations between various
yield bialgebra homomorphisms and sub-bialgebras, corresponding for example to
truncation of Dyson-Schwinger equations. Finally, all constructions can be
pushed inside the classical Connes-Kreimer Hopf algebra of trees by the
operation of taking core of -trees. A byproduct of the theory is an
interpretation of combinatorial Green functions as inductive data types in the
sense of Martin-L\"of Type Theory (expounded elsewhere).Comment: v4: minor adjustments, 49pp, final version to appear in J. Math. Phy
State sum construction of two-dimensional open-closed Topological Quantum Field Theories
We present a state sum construction of two-dimensional extended Topological
Quantum Field Theories (TQFTs), so-called open-closed TQFTs, which generalizes
the state sum of Fukuma--Hosono--Kawai from triangulations of conventional
two-dimensional cobordisms to those of open-closed cobordisms, i.e. smooth
compact oriented 2-manifolds with corners that have a particular global
structure. This construction reveals the topological interpretation of the
associative algebra on which the state sum is based, as the vector space that
the TQFT assigns to the unit interval. Extending the notion of a
two-dimensional TQFT from cobordisms to suitable manifolds with corners
therefore makes the relationship between the global description of the TQFT in
terms of a functor into the category of vector spaces and the local description
in terms of a state sum fully transparent. We also illustrate the state sum
construction of an open-closed TQFT with a finite set of D-branes using the
example of the groupoid algebra of a finite groupoid.Comment: 33 pages; LaTeX2e with xypic and pstricks macros; v2: typos correcte
Reproductive parameters in free-ranging female black rhinoceroses (Diceros bicornis) in Zimbabwe
Samples and data were collected from twenty-eight female black rhinoceroses (Diceros bicornis) during translocation efforts carried out by the Department of National Parks and Wildlife Management in Zimbabwe. Biological data were collected, cytological examination of vaginal smears was performed, and serum concentrations of follicle stimulating hormone, luteinizing hormone, progesterone, oestriol, and 17-β-oestradiol were determined by radio-immuno-assay. Prolactin levels were determined for 3 pregnant animals, 1 of which was sampled before and after parturition. Vaginal cytology was not found to be helpful for indicating the oestrous cycle stage for the black rhinoceros, but progesterone and 17-β–oestradiol levels were found to be useful indicators of pregnancy and possibly of oestrous cycle stage as well.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.University of Zimbabwe Research Board.mn201
The Impact of Online Social Networks on Decision Support Systems
Previous research on this matter had already determined that many
concepts are encompassed by both online social networking and decision support
systems research. Due to the large number of concepts and using clustering
techniques, we were able to determine four concept clusters, namely: the
technical infrastructure, online communities, network analysis and knowledge
management. Then, we intended to gain further knowledge on how those
concepts influenced DSS related research and the contribution of each cluster to
the support of the phases of decision-making process. We also wanted to perceive
the interconnections among the concept clusters themselves, for which we used
structural equation modeling techniques.
The obtained results evidence that not only online social networks are being used
as a technical infrastructure to support the three decision making phases and to
support knowledge management and online communities, but also that the other
clusters only regard the intelligence phase of the decision process.info:eu-repo/semantics/publishedVersio
Experimental Infection of Sheep using Infective Larvae (L3) harvested from the Faeces of Naturally Infected Swayne’s Hartebeest (Alcelaphus buselaphus swaynei) at Senkele Swayne’s Hartebeest Sanctuary, Ethiopia
Experimental infection of sheep using nematode larvae recovered from the faeces of naturally infected endangered Swayne’s Hartebeest (SHB) was carried out from December/2006 - April/2007 to assess the potential for the inter–species transmission of helminths. Faecal samples were collected from Swayne’s Hartebeest without preservatives and cultivated at room temperature for 21 days. Infective larvae were collected overnight by Baermann’s Method and identified and counted under a microscope. The sample was divided into eight aliquots of 9400 infective larvae and drenched into eight worm-free sheep kept at zero grazing. After 30 days, faecal samples from infected sheep were examined for ova for further 30 days by the Modified McMaster Method. Adult nematodes were recovered from the infected sheep at post mortem examination and distinguished based on position of barbs, shape and length of spicule, position of cervical papillae and mouth parts. The mean eggs per gram of faeces (EPG) from all infected sheep was 9192 ± 1422. Haemonchus placei (86.3%) from abomasums, Oespophagostomum venulosum (13.3%) and Trichuris spp (0.3%) from large intestine were identified. No ova and adult parasite were recovered from the control sheep. The study demonstrated that transmission of helminths between Swayne’s Hartebeest and sheep is experimentally possible. This is the first study conducted on the potential inter-species transmission of parasites between Swayne’s Hartebeest and local sheep and fur ther research is recommended to determine the impact of multiple-species habitat use, on pasture contamination and any associated pathological impact.Key words: Eexperimental infection, helminths, inter-species transmission, local sheep, Swayne’s Hartebees
EUREGIO MRSA-net Twente/Munsterland - a Dutch-German cross-border network for the prevention and control of infections caused by methicillin-resistant Staphylococcus aureus
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