Search results for "Clos"
showing 10 items of 1439 documents
F-signature of pairs: Continuity, p-fractals and minimal log discrepancies
2011
This paper contains a number of observations on the {$F$-signature} of triples $(R,\Delta,\ba^t)$ introduced in our previous joint work. We first show that the $F$-signature $s(R,\Delta,\ba^t)$ is continuous as a function of $t$, and for principal ideals $\ba$ even convex. We then further deduce, for fixed $t$, that the $F$-signature is lower semi-continuous as a function on $\Spec R$ when $R$ is regular and $\ba$ is principal. We also point out the close relationship of the signature function in this setting to the works of Monsky and Teixeira on Hilbert-Kunz multiplicity and $p$-fractals. Finally, we conclude by showing that the minimal log discrepancy of an arbitrary triple $(R,\Delta,\b…
On operads, bimodules and analytic functors
2017
We develop further the theory of operads and analytic functors. In particular, we introduce a bicategory that has operads as 0-cells, operad bimodules as 1-cells and operad bimodule maps as 2-cells, and prove that this bicategory is cartesian closed. In order to obtain this result, we extend the theory of distributors and the formal theory of monads.
Recent Nordic research in mathematics education illustrated by examples from NORMA17
2021
A characterization of recent Nordic research in didactics of mathematics is presented based on the 32 research reports from the Nordic and Baltic countries in the proceedings from NORMA17 (The eighth Nordic conference on didactics of mathematics). Recent Nordic research in didactics of mathematics is observed from several aspects such as choice of problem, theory, method, result, and target for the message. The analyses of the papers on different levels and from a manifold of perspectives build up an image of what Nordic research in DM (didactics of mathematics) contains and represents currently. The closeness and cooperation between researchers in the Nordic countries is characteristic as …
Explicit closed form solutions of boundary value problems for systems of difference equations
1990
In this paper boundary value problems for systems of difference equations of the type , where A j ∈ C p×p and bn y j+n ∈ C p , for 0≤j≤k − 1, are studied from an algebraic point of view. Existence conditions and closed form solutions are given in terms of co-solutions of the algebraic matrix equation .
Violenza di prossimità
2013
The essay reflects on the effects that the loss of power on the part of the male gender determines today in male-female relationships. Il saggio riflette sugli effetti che la perdita di potere maschile nell'ambito pubblico, determina oggi una sorta di revanche da parte defli stessi all'interno delle relazioni uomo-donna
Cyclosporin A resistance of herpes simplex virus-induced "fusion from within" as a phenotypical marker of mutations in the Syn 3 locus of the glycopr…
1994
We here report research in which nine strains of Herpes simplex virus (HSV) with fusing activity were investigated in order to establish precise phenotypical markers of mutations in the carboxy terminus of glycoprotein B (gB). The gene region encoding the carboxy terminus of gB was isolated, then cloned, and finally sequenced. Our investigation showed that seven strains have different mutations in the syn 3 locus. We observed no base difference in the gB gene region encoding the carboxy terminus of gB of two other strains. Strains with a mutation in the carboxy terminus of gB induced fusion from within (FFWI) in the presence of Cyclosporin A (CyA) at a concentration up to 150 µM. There are …
Clostridium difficile IStron CdISt1: Discovery of a Variant Encoding Two Complete Transposase-Like Proteins
2004
ABSTRACT Screening a Clostridium difficile strain collection for the chimeric element Cd ISt1 , we identified two additional variants, designated Cd ISt1 -0 and Cd ISt1 -III. In in vitro assays, we could prove the self-splicing ribozyme activity of these variants. Structural comparison of all known Cd ISt1 variants led us to define four types of IStrons that we designated Cd ISt1 -0 through Cd ISt1 -III. Since Cd ISt1 -0 encodes two complete transposase-like proteins (TlpA and TlpB), we suggest that it represents the original genetic element, hypothesized before to have originated by fusion of a group I intron and an insertion sequence element.
Planar Cell Polarity Signaling in Collective Cell Movements During Morphogenesis and Disease
2012
Collective and directed cell movements are crucial for diverse developmental processes in the animal kingdom, but they are also involved in wound repair and disease. During these processes groups of cells are oriented within the tissue plane, which is referred to as planar cell polarity (PCP). This requires a tight regulation that is in part conducted by the PCP pathway. Although this pathway was initially characterized in flies, subsequent studies in vertebrates revealed a set of conserved core factors but also effector molecules and signal modulators, which build the fundamental PCP machinery. The PCP pathway in Drosophila regulates several developmental processes involving collective cel…
The IStron CdISt1 of Clostridium difficile: molecular symbiosis of a group I intron and an insertion element
2003
Abstract The IStron CdISt1 was first discovered as an insertion into the tcdA gene of the clinical isolate C34. It combines structural and functional properties of a group I intron at its 5′-end with those of an insertion element at its 3′-end. Up to date four different types could be found, mainly differing in their IS-element portions. Contrasting classical group I introns, CdISt1 is always integrated in ORFs encoding bacterial protein. In case CdISt1 had only the IS-element function such insertion would inactivate the protein encoded by the host gene. It is only due to the self-splicing activity of the group I intron parts that CdISt1 integration does not abolish protein function. Both e…
Characterization of polymorphisms in the toxin A and B genes of Clostridium difficile.
2006
We have used six independent polymerase chain reactions (A1–A3 and B1–B3) for amplification of the entire sequence of the two toxin genes tcdA and tcdB of several Clostridium difficile strains. With this approach we have detected (1) restriction site polymorphisms which are distributed all over the genes, and (2) deletions that could be found only in tcdA. Characteristic differences between strains were mainly focused to the 5′ third of tcdB (B1 fragment) and/or the 3′ third of tcdA (A3 fragment). The possible use of our approach for typing of C. difficile toxin genes is discussed.