Ring Research Papers - Academia.edu (original) (raw)

Abstract. We study Rickard equivalences between p-blocks of twisted group algebras and their local structure, in connection with Dade's conjectures. We prove that an extended form of Broué's conjecture implies Dade's... more

Abstract. We study Rickard equivalences between p-blocks of twisted group algebras and their local structure, in connection with Dade's conjectures. We prove that an extended form of Broué's conjecture implies Dade's Inductive Conjecture in the Abelian defect group case; this is a ...

The most marked tree-ring growth anomaly in the Aegean dendrochronological record over the last 9000 years occurs in the mid 17th century BC, and has been speculatively correlated with the impact of the Late Bronze Age eruption of Thera... more

The most marked tree-ring growth anomaly in the Aegean dendrochronological record over the last 9000 years occurs in the mid 17th century BC, and has been speculatively correlated with the impact of the Late Bronze Age eruption of Thera (Santorini). If such a connection could be proved it would be of major interdisciplinary significance. It would open up the possibility of a precise date for a key archaeological, geological and environmental marker horizon, and offer a direct tie between tree-ring and ice-core records some 3600 years ago. A volcanic explanation for the anomaly is highly plausible, yet, in the absence of a scientifically proven causal connection, the value of the proposed correlation is limited. In order to test the hypothesis, dendrochemical analysis via Synchrotron Radiation Scanning X-ray Fluorescence Microscopy (SXFM), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) was carried out on growth-ring series from four trees displaying the anomaly. Increases of sulfur, calcium, and rare earth elements following the onset of altered growth, plus concentration spikes of zinc and hafnium in the first affected growth-ring provide promising new evidence in support of a volcanic causal factor. Although a volcanic association is implied, the new data are not sufficient to prove a link to the exact eruption source.

We study the complexity of the isomorphism and automorphism problems for finite rings. We show that both integer factorization and graph isomorphism reduce to the problem of counting automorphisms of a ring. This counting problem is shown... more

We study the complexity of the isomorphism and automorphism problems for finite rings. We show that both integer factorization and graph isomorphism reduce to the problem of counting automorphisms of a ring. This counting problem is shown to be in the functional version of the complexity class AM ∩ coAM and hence is not NP-complete unless the polynomial hierarchy collapses. As a “positive” result we show that deciding whether a given ring has a non-trivial automorphism can be done in deterministic polynomial time. Finding such an automorphism is, however, shown to be randomly equivalent to integer factorization.

This chapter introduces a brief history review of Internet with focus on its original conception. It’s important to remember such initial ideas because they were the basis of Internet architecture, they are still at the core of today’s... more

This chapter introduces a brief history review of Internet with focus on its original conception. It’s important to remember such initial ideas because they were the basis of Internet architecture, they are still at the core of today’s Internet and they can be helpful to rethink new design requirements nowadays. Hence, we start by the initial packet-based network protocols and their evolution to TCP/IP.

Cernek - a new bird ringing station in Turkey A new Turkish bird ringing station - Cernek, was launched on 22 March 2002 under the auspices of the SE European Bird Migration Network (SEEN). This paper provides information about the... more

Cernek - a new bird ringing station in Turkey A new Turkish bird ringing station - Cernek, was launched on 22 March 2002 under the auspices of the SE European Bird Migration Network (SEEN). This paper provides information about the location and biotopes of the station, methodology used in its work, species composition of captured birds and presents plans and perspectives for future research.

... Dies., GRUPS and ArcGRIMP: a new system for digital excavation documentation and importing recor-ded data to a GIS, in: Enter ... 9. – M. Vaquero et al.,Intrasite Spatial Patterning and Transport in the Abric Romaní Middle Paleolithic... more

... Dies., GRUPS and ArcGRIMP: a new system for digital excavation documentation and importing recor-ded data to a GIS, in: Enter ... 9. – M. Vaquero et al.,Intrasite Spatial Patterning and Transport in the Abric Romaní Middle Paleolithic Site (Capellades, Barcelona, Spain), in: NJ ...