Oyster shells as history books

[FIRST PARAGRAPH] A collaborative project was established in 2002 that has brought together geochemistry and archaeology in order to investigate environmental change and the harvesting strategies of ancient peoples. The objectives of this study are to decipher the life history and environmental information contained in shells of the European oyster, Ostrea edulis, by analyzing geochemical variations along shell growth. This approach provides an independent measure of age and season of death, as well as a record of environmental change in temperature and salinity through the life of the oyster. By understanding the life history and environmental records contained in modern oyster shells, we can analyze shells from archaeological sites to gain an historical perspective of harvesting practices and environmental change in ancient shellfisheries

Globalisation and the rise of india and china: challenges and opportunities for the East Midlands

Review of literature around the recent (late 20th Century) phase of globalisation, with particular focus on the developing economies of India and China. Includes an economic and policy review of the East Midlands - identifying business and strategic challenges/opportunities for the region

Contending with animal bones (Editorial)

[FIRST PARAGRAPH] This issue has been assembled in order to focus on some of the current directions in animal remains research. Since serious study of ancient animal remains began in the nineteenth century, this field and its specific areas of inquiry have evolved and diversified, and this collection of papers highlights that diversity, by including contributions that address issues from excavation and field recording methods and preservational conditions, to the use of bone for understanding past animal populations, as well as bones as proxy indicators for human activities. This volume is not meant only for the attention of the faunal remains specialist, and only a couple of these papers have actually been contributed by "archaeozoologists". Rather we hope to demonstrate the importance of faunal remains studies, on a par with lithic or pottery research. It should be acknowledged that animal bones do not relate simply to the “economic” aspects of a culture but to all areas of the life world

Design of a high-speed digital processing element for parallel simulation

A prototype of a custom designed computer to be used as a processing element in a multiprocessor based jet engine simulator is described. The purpose of the custom design was to give the computer the speed and versatility required to simulate a jet engine in real time. Real time simulations are needed for closed loop testing of digital electronic engine controls. The prototype computer has a microcycle time of 133 nanoseconds. This speed was achieved by: prefetching the next instruction while the current one is executing, transporting data using high speed data busses, and using state of the art components such as a very large scale integration (VLSI) multiplier. Included are discussions of processing element requirements, design philosophy, the architecture of the custom designed processing element, the comprehensive instruction set, the diagnostic support software, and the development status of the custom design

Simulating a small turboshaft engine in real-time multiprocessor simulator (RTMPS) environment

A Real-Time Multiprocessor Simulator (RTMPS) has been developed at NASA Lewis Research Center. The RTMPS uses parallel microprocessors to achieve computing speeds needed for real-time engine simulation. This report describes the use of the RTMPS system to simulate a small turboshaft engine. The process of programming the engine equations and distributing them over one, two, and four processors is discussed. Steady-state and transient results from the RTMPS simulation are compared with results from a main-frame-based simulation. Processor execution times and the associated execution time savings for the two and four processor cases are presented using actual data obtained from the RTMPS system. Included is a discussion of why the minimum achievable calculation time for the turboshaft engine model was attained using four processors. Finally, future enhancements to the RTMPS system are discussed including the development of a generalized partitioning algorithm to automatically distribute the system equations among the processors in optimum fashion

Partitioning and packing mathematical simulation models for calculation on parallel computers

The development of multiprocessor simulations from a serial set of ordinary differential equations describing a physical system is described. Degrees of parallelism (i.e., coupling between the equations) and their impact on parallel processing are discussed. The problem of identifying computational parallelism within sets of closely coupled equations that require the exchange of current values of variables is described. A technique is presented for identifying this parallelism and for partitioning the equations for parallel solution on a multiprocessor. An algorithm which packs the equations into a minimum number of processors is also described. The results of the packing algorithm when applied to a turbojet engine model are presented in terms of processor utilization

Liquid Crystal Polarimetry for Metastability Exchange Optical Pumping of 3He

We detail the design and operation of a compact, discharge light polarimeter for metastability exchange optical pumping of 3He gas near 1 torr under a low magnetic field. The nuclear polarization of 3He can be discerned from its electron polarization, measured via the circular polarization of 668 nm discharge light from an RF excitation. This apparatus measures the circular polarization of this very dim discharge light using a nematic liquid crystal wave retarder (LCR) and a high-gain, transimpedance amplified Si photodiode. We outline corrections required in such a measurement, and discuss contributions to its systematic error

Causality and replication in concurrent processes

The replication operator was introduced by Milner for obtaining a simplified description of recursive processes. The standard interleaving semantics denotes the replication of a process P, written !P, a shorthand for its unbound parallel composition, operationally equivalent to the process P | P | …, with P repeated as many times as needed. Albeit the replication mechanism has become increasingly popular, investigations on its causal semantics has been scarce. In fact, the correspondence between replication and unbound parallelism makes it difficult to recover basic properties usually associated with these semantics, such as the so-called concurrency diamond. In this paper we consider the interleaving semantics for the operator proposed by Sangiorgi and Walker, and we show how to refine it in order to capture causality. Furthermore, we prove it coincident with the standard causal semantics for recursive process studied in the literature, for processes defined by means of constant invocations