Recombination. The New Lease will include provisions to allow for recombination of the Original Lease with the New Lease at Landlord’s discretion provided such recombination shall (i) not involve the combination of the New Lease with leases other than the Original Lease (including its predecessors and successors) or (ii) result in the combination of any properties other than those at any time subject to the Original Lease (including its predecessors and successors) and such recombination shall be further subject to the following:
Recombination. Like for selection, for recombination there are many different approaches, but unlike for selection the representation of the individual has a great im- pact on which recombination operator can be used. Because recombination is performed in the genotype, calculating the average between two points (‘Intermediate Recombination’) is not possible on an individual represented by a binary array. Some popular examples of recombination are: µ Copy does not really recombine anything, but does generate offspring and therefore belongs in this step. Note that there are different ways to select a single parent multiple times which can have a big impact on the algo- rithm’s behavior. In this thesis we only use the copy operator to copy a parent exactly λ times, but basing this on rank or fitness or even making it probabilistic is not uncommon. Crossover is only used on binary representations. It generates the binary array of the offspring by combining the binary arrays of randomly chosen parents. This is usually done on only 2 parents, but in theory can be done on more than 2. There are a few different ways to combine two binary ar- rays: • With ‘Uniform Crossover’ every single bit has an equal probability to come from either parent. • With ‘Single Point Crossover’ a split point is chosen at random and all bits until that point are copied from one parent and all other bits from the other. This only works with 2 parents. • With ‘Multi Point Crossover’ multiple split points are chosen at ran- dom and the source of the bits changes to the next parent with every split point along the bit array. Note that because parents are usually chosen randomly one parent can be chosen multiple times. Not only for multiple offspring, but even for the same offspring. This means that if all parents chosen for the offspring are one and the same, that parent is ‘copied’ without changes. Intermediate Recombination is mostly used in Evolutionary Strategies. It combines multiple parents by calculating the average values for each value in the real valued arrays of the individuals. In some popular algo- rithms a weighted average is used instead, weighted on the rank if the par- ents in the population. In this thesis only Copy and Crossover recombination are used.
Recombination of Subproblems During pilot deployment we used the Problem Frames model for solving the recombination problem of subproblems. Although we managed to recombine the subproblems after several iterations of constructing different Problem Frames models we learnt that Problem Frames is in fact not the optimal method for solving the recombination problem. Problem Frames is very good for analyzing the requirements but not optimal for writing a specification. Consequences for Enhanced Deployment As a consequence of the lessons learnt described above we decided to intro- duce another process phase for the enhanced deployment, namely the speci- fication phase (see also Chapter 3). The input to this phase is the Problem Frames model and the requirements document (as described in Chapter 4). The output of this phase is a detailed specification document describing the static structure and the dynamic behaviour of the SSE. In addition to the introduction of the specification phase we decided to use the Problem Frames model for the description of requirements and as- sumptions of the environment and not for the description of the specification. We believe that this strict separation of requirements analysis and specifica- tion is a better way of dealing with these two important development tasks before the formal modelling in Event-B. In the following we will describe the specification of the SSE in more detail.
Recombination. The recombinant adenoviruses can revert to wild type during virus production, thus packaging replication competent particles (RCA). For this reason, each new lot produced at the core is tested for the presence of RCA by immuno-staining. References: • RapAdTM System: Xxxxxxxx XX, Xxxxxxx RE, Xxx H, Xxxxxxxx XX, Xxxxxxxx XX. “A simple method for the rapid generation of recombinant adenovirus vectors”. Gene Ther. 2000 Jun;7(12):1034-8 • A195 Xxxxxx: Xxxxx XX, Xxxxxxxx XX, Xxxxx LA, Xxxxxxxx XX, Xxxxxxxx DR, Xxxx S, Xxxx M, Xxx XX, Xxxxxx XX, Xxxxxx XX. Development of stable liquid formulations for adenovirus-based vaccines. J Pharm Sci. 2004 Oct;93(10):2458-7 Contact Information: Viral Vector Core University of Iowa 000 Xxxxxx Xxxx 000 Xxxxxxxx Xxxxxxx Research Building Iowa City, IA 52242 Tel: (000) 000-0000 xxxxxxx@xxxxx.xxx Background on Virus production The virus was made with our pacAd5(9.2-100)sub360 viral backbone. This backbone has a fully deleted E1a protein, a partially deleted E1b protein, and a partially deleted E3 protein to make the virus replication deficient. All of our Ad5mSPCFLPO vector preparations infected in HEK293 cells, purified by double CsCl protocol, and dialyzed and stored in our A-195 buffer. All preparations are titered on HEK 293 cells using the Clonetech Adeno-X titer kits and also tested for replication competent particles (RCA). Bacterial Backbone: The bacterial backbone is derived from pBR322 plasmid.
