The dynamic unpredictable nature of serviceoriented environments demands service-based systems to be inherently flexible and adaptive. In this paper, we propose a constraint-based framework for supporting dynamic business process adaptation. In our framework, process adaptations are performed in a modular way based on process fragments. Process fragments are standalone fragments of processes that can be reused across multiple processes. Processes are composed of a series of fragments. The relationships among fragments are specified in a constraint-based way. The adaptation logic to select concrete fragments is separated from business logic in a process and can be defined in a policy-based approach. Processes are dynamically generated based on the constraints and adaptation policies according to the operating environments, so it is flexible to adapt to the ever-changing operating environments and business requirements. We have implemented a prototype to demonstrate and evaluate our approach.

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Background Leaf morphology is an important component of the idea plant architecture that extensively influences photosynthesis, transpiration, and ultimately grain yield in crops. However, the genetic and molecular mechanisms regulating this morphology remain largely unclear. Results In this study, a mutant showing a narrow and stripe leaf phonotype, designated nsl2, was obtained. Histological analysis revealed defects in the vascular system and reduced epidermal cell number in the nsl2, while the cell size remained unchanged. Map-based cloning and genetic complementation experiments revealed that NSL2, which encodes a small subunit of ribonucleotide reductases (RNRs), is a null allelic with ST1 and SDL. The NSL2 was expressed in variety of tissues, with the highest levels detected in leaves, and its protein was localized in the nucleus and cytoplasm. The dNTPs level was altered in the nsl2 mutant, and thereby affecting the dNTPs pool balance. In addition, flow cytometric analysis and the altered transcript level of genes related to cell cycle indicated that NSL2 affects cell cycle progression. Conclusions Our findings here suggest that NSL2 function in the synthesis of dNTP, the deficient of which leads to DNA synthesis block and in turn affects cell cycle progression, and ultimately decreased cell number and narrow leaf in the nsl2 plant.