| 1. |
- Bourquin, V., et al.
(författare)
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Xyloglucan endotransglycosylases have a function during the formation of secondary cell walls of vascular tissues
- 2002
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Ingår i: The Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 14:12, s. 3073-3088
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Tidskriftsartikel (refereegranskat)abstract
- Xyloglucan transglycosylases (XETs) have been implicated in many aspects of cell wall biosynthesis, but their function in vascular tissues, in general, and in the formation of secondary walls, in particular, is less well understood. Using an in situ XET activity assay in poplar stems, we have demonstrated XET activity in xylem and phloem fibers at the stage of secondary wall formation. Immunolocalization of fucosylated xylogucan with CCRC-M1 antibodies showed that levels of this species increased at the border between the primary and secondary wall layers at the time of secondary wall deposition. Furthermore, one of the most abundant XET isoforms in secondary vascular tissues (PttXET16A) was cloned and immunolocalized to fibers at the stage of secondary wall formation. Together, these data strongly suggest that XET has a previously unreported role in restructuring primary walls at the time when secondary wall layers are deposited, probably creating and reinforcing the connections between the primary and secondary wall layers. We also observed that xylogucan is incorporated at a high level in the inner layer of nacreous walls of mature sieve tube elements.
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| 2. |
- Eklund, Patrik, 1958-, et al.
(författare)
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A categorical approach to unication of generalised terms
- 2002
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Ingår i: Electronic Notes in Theoretical Computer Science. - : Elsevier. - 1571-0661. ; 66:5, s. 41-45
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Tidskriftsartikel (refereegranskat)abstract
- Unification of generalised terms in a many-valued setting involves considerations for equalities in the sense of similarity degrees between operators and thus similarities between terms. Further, allowing for substitutions of variables with powersets of terms requires ‘flattening’ operators for handling composition of variable substitutions. These techniques are available when using powerset functors composed with the term functor so that this composition of functors is extendable to a monad. In this paper we provide a framework for unification of such generalised terms.
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| 3. |
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| 4. |
- Eklund, Patrik, 1958-, et al.
(författare)
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A framework for unication using powersets of terms
- 2002
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Ingår i: Proc. 9th Information Processing and Management of Uncertainty in Knowledge Based Systems Conference (IPMU 2002). ; , s. 1095-1098
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Konferensbidrag (refereegranskat)
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| 5. |
- Eklund, Patrik, 1958-, et al.
(författare)
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A graphical approach to monad composition
- 2001
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Ingår i: Electronic Notes in Theoretical Computer Science. - 1571-0661. ; 40, s. 145-160
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we show how composite expressions involving natural transformations can be pictorially represented in order to provide graphical proof support for providing monad compositions. Examples are drawn using powerset monads composed with the term monad.
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| 6. |
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| 7. |
- Eklund, Patrik, 1958-, et al.
(författare)
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Composing submonads
- 2001
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Ingår i: 31st IEEE International Symposium on Multiple-Valued Logic, 2001. Proceedings.. - Warsaw, Poland : IEEE Computer Society. - 0769510833 ; , s. 367-372
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Konferensbidrag (refereegranskat)abstract
- In this paper we use the concept of subfunctors and submonads in order to provide a technique for constructing new monads from given ones. We study some properties of these constructions and provide more examples on monad compositions
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| 8. |
- Eklund, Patrik, et al.
(författare)
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Powersets of Terms and Composite Monads
- 2004
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Ingår i: Technical Report, UMINF. - Umeå : Department of Computing Science. - 0348-0542. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- Composing various powerset functors with the term monad gives rise to the concept of generalised terms. This in turn provides a technique for handling many-valued sets of terms in a framework of variable substitutions, thus being the prerequisite for categorical unification in many-valued logic programming using an extended notion of terms. As constructions of monads involve complicated calculations with natural transformations, proofs are supported by a graphical approach that provides a useful tool for handling various conditions, such as those well-known for distributive laws.
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| 9. |
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| 10. |
- Eklund, Patrik, et al.
(författare)
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Setfunctors, L-fuzzysetcategories, and generalizedterms
- 2002
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Ingår i: Computers and Mathematics with Applications. - : Elsevier. - 0898-1221 .- 1873-7668. ; 43:6-7, s. 693-705
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we generalize previous constructions of fuzzysetcategories, introduced in [1], by consideringL-fuzzysets in which the values of the characteristic functions run on a completely distributive lattice, rather than in the unit real interval. Later, these L-fuzzysets are used to define the L-fuzzycategories, which are proven to be rational. In the final part of the paper, the L-fuzzyfunctors given by the extension principles are provided with a structure of monad which is used, together with the functorial definition of theterm monad, to provide monad compositions as a basis for a notion of generalisedterms.
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