Cc

We investigated, by a photoacoustic method, the changes in light energy distribution to the reaction centres upon state transitions in vivo in Chlamydomonas reinhardtii. We present spectra of the quantum yield of charge separation in the wild type and in several photosynthesis mutants lacking either cytochrome b6f complexes, the PS II cores or the PS I cores. Our results show unambiguously that in the wild-type LHCII becomes connected to PS I in state 2, in a cyt b6f-controlled process. We show that mutants lacking the PS II cores, but not those lacking PS I cores, display a behaviour very similar to that of the wild type upon state transition. Lateral displacement of LHCII, but not of minor antenna complexes (CP26), from the stacked to the unstacked membrane domains results in transfer to PS I of about 80% of the excitation energy absorbed by LHCII. Consequently, in state 2, more than 90% of the chlorophylls transfer energy to PS I in mutants lacking PS II cores. In contrast, a sig...

Defining algorithms in a way which allows parallel execution is becoming increasingly important as multicore computers become ubiquitous. We present IFDS-A, a parallel algorithm for solving context-sensitive interprocedural finite distributive subset (IFDS) dataflow problems. IFDS-A defines these problems in terms of Actors, and dataflow dependencies as messages passed between these Actors. We implement the algorithm in Scala, and evaluate its performance against a comparable sequential algorithm. With eight cores, IFDS-A is 6.12 times as fast as with one core, and 3.35 times as fast as a baseline sequential algorithm. We also found that Scala’s default Actors implementation is not optimal for this algorithm, and that a custom-built implementation outperforms it by a significant margin. We conclude that Actors are an effective way to parallelize this type of algorithm.

An aircraft is a complex, multi-disciplinary, system-engineered product that requires real-time global technical collaboration through its life-cycle. Engineering data and processes which form the backbone of the aircraft should be under strict Configuration Control (CC). It should be model-based and allow for 3D visualization and manipulation. This requires accurate, realtime collaboration and concurrent engineering-based business processes operating in an Integrated Digital Environment (IDE). The IDE uses lightweight, neutral Computer Aided Design (CAD) Digital Mock-Up (DMU). The DMU deals with complex structural assemblies and systems of more than a hundred thousand parts created by engineers across the globe, each using diverse CAD, Computer Aided Engineering (CAE), Computer Aided Manufacturing (CAM), Computer Integrated Manufacturing (CIM), Enterprise Resource Planning (ERP), Supply Chain Management(SCM),Customer Relationship Management(CRM) and Computer Aided Maintenance Management System (CAMMS) systems. In this paper, a comprehensive approach to making such an environment a reality is presented.

Adhesive bonding technology has played an essential role in the development and growth of the rehabilitation and repair of timber structures. The ability of a structural joint to maintain satisfactory long-term performance, often in severe environments, is an important requirement of a ...

This policy note reviewed the status of farm machinery in the Kyrgyz Republic. Agricultural productivity, particularly in terms of grain yields, is low because of underinvestment. This note finds that a significant deficit in agricultural machinery is hindering sector productivity. The Kyrgyz Republic has fewer tractors per hectare than any comparable country, with a deficit estimated at 40 percent. The deficit of combine harvesters, estimated at 45 percent, is even more critical. When the age of agricultural machinery is taken into account, the underinvestment becomes even more acute. The reduced domestic production of wheat exacerbates food security concerns. Inadequate access to credit and small farm size are the main factors that constrain farm mechanization. The policy note presents three sets of short- to medium-term policy options to: i) promote the demand for farm machinery, by developing credit lines for agricultural productive assets, leasing, facilitating access to second...

Given an array of n input numbers, the range-maxima problem is to preprocess the data so that queries of the type “what is the maximum value in subarray [i..j]” can be answered quickly using one processor. We present a randomized preprocessing algorithm that runs in O(log*n) time with high probability, using an optimal number of processors on a CRCW PRAM; each query can be processed in constant time by one processor. We also present a randomized algorithm for a parallel comparison model. Using an optimal number of processors, the preprocessing algorithm runs in O(α(n)) time with high probability; each query can be processed in O(α(n)) time by one processor. (α(n) is the inverse of Ackermann function.) A constant time query can be achieved by some slowdown in the performance of the preprocessing stage.