Vector Field Induced Chaos in Multi-dimensional Homogeneous Cosmologies

We show that in multidimensional gravity vector fields completely determine the structure and properties of singularity. It turns out that in the presence of a vector field the oscillatory regime exists for any number of spatial dimensions and for all homogeneous models. We derive the Poincar\'e return map associated to the Kasner indexes and fix the rules according to which the Kasner vectors rotate. In correspondence to a 4-dimensional space time, the oscillatory regime here constructed overlap the usual Belinski-Khalatnikov-Liftshitz one.Comment: 3 pages, proceedings of the XI Marcel Grossmann meeting on Relativistic Astrophysics, July 23-29, 2006, Berli

On the existence of elementary abelian cycle systems

We present some necessary and/or sufficient conditions for the existence of an elementary abelian cycle system of the complete graph.We propose a construction for some classes of perfect elementary abelian cycle systems. Finally we consider elementary abelian k-cycle systems of the complete multipartite graph

Liouville/Toda central charges from M5-branes

We show that the central charge of the Liouville and ADE Toda theories can be reproduced by equivariantly integrating the anomaly eight-form of the corresponding six-dimensional N=(0,2) theories, which describe the low-energy dynamics of M5-branes.Comment: 9 page

Partially Balanced Incomplete Block Designs from Weakly Divisible Nearrings

In [[6] Riv. Mat. Univ. Parma 11 (2) (1970) 79–96] Ferrero demonstrates a connection between a restricted class of planar nearrings and balanced incomplete block designs. In this paper, bearing in mind the links between planar nearrings and weakly divisible nearrings (wd-nearrings), first we show the construction of a family of partially balanced incomplete block designs from a special class of wd-nearrings; consequently, we are able to give some formulas for calculating the design parameters

Finite weakly divisible nearrings

In [5] we dened and studied the algebraic structure called weakly divisible nearring (wd-nearring). In [1, 2] a special class of finite wd-nearrings on Z_{p^n}, p prime, was constructed: on the group (Z_{p^n}; +) of the residue classes (mod p^n) a multiplication "*" can be dened in such a way that (Z_{p^n};+; *) becomes a wd-nearring. Afterwards, in [3, 4] Partially Balanced Incomplete Block Designs (PBIBDs) and codes were obtained starting from the wd-nearrings of [1, 2] and formulae for computing their parameters could be derived just making use of the combinatorial properties of the constructed algebraic structure. In [9] the construction of [1, 2] was generalized to any wd-nearring. Applying Prop. 1 of [9], in Example 2.1 of this paper a wd-nearring N = (Z_7^2 ;+; *) is constructed on the elementary abelian group (Z_7^2 ; +) and a PBIBD is obtained from N. Using the algebraic properties of N = (Z_7^2 ;+; *), all the parameters of the PBIBD are computed. Since it seems reasonable to think the construction and the method to compute all the parameters in [3] could be extended to some additional classes of wd-nearrings, the aim of this paper is to study in more depth the algebraic structure of any finite wd-nearring, especially with regard to determining the size of the elements of signicant structures in N, as partitions, normal chains and products. In the next paragraph, the main definitions and properties of a finite wd-nearring are recalled (Remark 2.1) and the most signicant results presented in this paper are summarized (Remark 2.2)

Reducing Interconnect Cost in NoC through Serialized Asynchronous Links

This work investigates the application of serialization as a means of reducing the number of wires in NoC combined with asynchronous links in order to simplify the clocking of the link. Throughput is reduced but savings in routing area and reduction in power could make this attractiv

Evidence of active subsidence at Basiluzzo island (Aeolian islands, southern Italy) inferred from a Roman age wharf

The Aeolian Arc (Southern Tyrrhenian Sea, Italy) is one of the most active volcanic areas of the Mediterranean basin, affected by volcanic/hydrothermal and seismic activity. Ancient populations settled this region since historical times, building coastal installations which currently are valuable archaeological indicators of relative sea level changes and vertical land movements. In this study we show and discuss data on the relative sea level change estimated from a submerged wharf of Roman age dated between 50 B.C. and 50 A.D., located at Basiluzzo Island. This structure has been studied through marine surveys and archaeological interpretations and is presently located at a corrected depth of 4.10 0.2 m. We explain this submergence by a cumulative effect of the relative sea level change caused by the regional glaciohydro- isostatic signal, active since the end of the last glacial maximum, and the local volcano-tectonic land subsidence. Finally, a total subsidence rate of 2.05 0.1 mm/yr 1, with a volcano-tectonic contribution of 1.43 0.1 mm/yr 1 for the last 2 ka BP, is inferred from the comparison against the latest predicted sea level curve for the Southern Tyrrhenian Sea, suggesting new evaluations of the volcanotectonic hazard for this area of the Aeolian islands

Nilpotent orbits and codimension-two defects of 6d N=(2,0) theories

We study the local properties of a class of codimension-2 defects of the 6d N=(2,0) theories of type J=A,D,E labeled by nilpotent orbits of a Lie algebra \mathfrak{g}, where \mathfrak{g} is determined by J and the outer-automorphism twist around the defect. This class is a natural generalisation of the defects of the 6d theory of type SU(N) labeled by a Young diagram with N boxes. For any of these defects, we determine its contribution to the dimension of the Higgs branch, to the Coulomb branch operators and their scaling dimensions, to the 4d central charges a and c, and to the flavour central charge k.Comment: 57 pages, LaTeX2

N=2 Generalized Superconformal Quiver Gauge Theory

Four dimensional N=2 generalized superconformal field theory can be defined by compactifying six dimensional (0,2) theory on a Riemann surface with regular punctures. In previous studies, gauge coupling constant space is identified with the moduli space of punctured Riemann surface M_{g,n}. We show that the weakly coupled gauge group description corresponds to a stable nodal curve, and the coupling space is actually the Deligne-Mumford compactification \bar{M}_{g,n}. We also give an algorithm to determine the weakly coupled gauge group and matter content in any duality frame.Comment: v2, reorganizing the materials, discussions on 2d CFT is remove