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We compute the center of the ring of PD differential operators on a smooth variety over ℤ/pnℤ, confirming a conjecture of Kaledin (private communication). More generally, given an associative algebra A0 over ℤp and its flat deformation An over ℤ/pn+1ℤ, we prove that under a certain non-degeneracy condition, the center of An is isomorphic to the ring of length-(n+1) Witt vectors over the center of A0. [ABSTRACT FROM AUTHOR]

Abstract: We prove a formula expressing the motivic integral (Loeser and Sebag, 2003) of a K3 surface over with semi-stable reduction in terms of the associated limit mixed Hodge structure. Secondly, for every smooth variety over a complete discrete valuation field we define an analogue of the monodromy pairing, constructed by Grothendieck in the case of abelian varieties, and prove that our monodromy pairing is a birational invariant of the variety. Finally, we propose a conjectural formula for the motivic integral of maximally degenerate K3 surfaces over an arbitrary complete discrete valuation field and prove this conjecture for Kummer K3 surfaces. [Copyright &y& Elsevier]

RNA polymerase III (Poi III) transcribes small untranslated RNAs, such as tRNAs. To define the Poi III transcriptome in Saccharomyces cerevisiae, we performed genome-wide chromatin immunoprecipitation using subunits of Poi III, TFIIIB and TFIIIC. Virtually all of the predicted targets of Poi III, as well as several novel candidates, were occupied by Poi iii machinery. Interestingly, TATA boxbinding protein occupancy was greater at Poi III targets than virtually all Poi II targets, and the highly occupied Poi II targets are generally strongly transcribed. The temporal relationships between factor occupancy and gene activity were then investigated at selected targets. Nutrient deprivation rapidly reduced both Poi III transcription and Poi III occupancy of both a tRNA gene and RPR1. In contrast, TFIIIB remained bound, suggesting that TFIIIB release is not a critical aspect of the onset of repression. Remarkably, TFIIIC occupancy increased dramatically during repression. Nutrient addition generally reestablished transcription and initial occupancy levels. Our results are consistent with active Poi III displacing TFIIIC, and with inactivation/release of Poi Iii enabling TFIIIC to bind, marking targets for later activation. These studies reveal new aspects of the kinetics, dynamics, and targets of the Poi III system. [ABSTRACT FROM AUTHOR]

The use of corporal punishment is one of the most controversial parenting practices and it will continue to be controversial. Although the effects of corporal punishment on children is still undergoing rigorous scientific debate, less attention has been devoted to why parents spank their children. The primary concern of this review of issue of corporal punishment was to identify the major reason(s) why parent spank their child. The belief of the reviewer is that there can be no progress until more attention is devoted to why parents spank their children. This is the side of the issue that the critics failed to address. In this article, I describe and compare the prons and cons of issue of corporal punishment. Many educators support the old notion of spare the rod and spoil the child. As a result, they advocate paddling as a method of disciplining children in school. This reinforces the importance of early training in forming a person's lifelong character. [ABSTRACT FROM AUTHOR]

Modelling of pavement performance deterioration is a critical engineering process in Pavement Management Systems. Most of the existing Airport Pavement Management Systems (APMS) employ limited surface distresses in their performance evaluation models. These systems may not serve the objectives of some agencies. It is essential for an effective APMS to include evaluation models that adequately address the specific needs of the agency. This paper presents the development of a unique pavement deterioration index, i.e., the Condition Rating Index, developed for 1 Canadian Air Division (1 CAD). This index is modelled to serve the specific needs of 1 CAD effectively. Performance prediction models for the various classes of pavements are developed based on Markov Chains. The prioritization methodology employed also reflects the needs of 1 CAD. Consequently, this paper investigates the quantification and prediction of Foreign Object Damage (FODp). The FODp Index is developed as well as defined. Prediction models for FODp are developed along with the establishment of critical states of the FODp Index. [ABSTRACT FROM AUTHOR]

Mixtures of group-based Markov models of evolution correspond to joins of toric varieties. In this paper, we establish a large number of cases for which these phylogenetic join varieties realize their expected dimension, meaning that they are nondefective. Nondefectiveness is not only interesting from a geometric point-of-view, but has been used to establish combinatorial identifiability for several classes of phylogenetic mixture models. Our focus is on group-based models where the equivalence classes of identified parameters are orbits of a subgroup of the automorphism group of the abelian group defining the model. In particular, we show that for these group-based models, the variety corresponding to the mixture of r trees with n leaves is nondefective when n≥2r+5. We also give improved bounds for claw trees and give computational evidence that 2-tree and 3-tree mixtures are nondefective for small n. [ABSTRACT FROM AUTHOR]

Nutrient deprivation and various stress conditions repress RNA polymerase III (Pol III) transcription in S. cerevisiae. The signaling pathways that relay stress and nutrient conditions converge on the conserved protein Maf1, but how Maf1 integrates environmental conditions and couples them to transcriptional repression is largely unknown. Here, we demonstrate that Maf1 is phosphorylated in favorable conditions, whereas diverse unfavorable conditions lead to rapid Maf1 dephosphorylation, nuclear localization, physical association of dephosphorylated Maf1 with Pol III, and Maf1 targeting to Pol III-transcribed genes genome wide. Furthermore, Maf1 mutants defective in full dephosphorylation display maf1Δ phenotypes and are compromised for both nuclear localization and Pol III association. Repression conditions also promote TFIIIB-TFIIIC interactions in crosslinked chromatin. Taken together, Maf1 appears to integrate environmental conditions and signaling pathways through its phosphorylation state, with stress leading to dephosphorylation, association with Pol III at target loci, alterations in basal factor interactions, and transcriptional repression. [Copyright &y& Elsevier]