Transactional Memory (TM) is an approach to concurrency control in general pur- pose programming languages that inherits the concept of transaction from the database setting. Unlike other language constructs such as locks, TM has an optimistic approach to concurrency control by allowing more than one thread to access simultaneously the same critical section. A transaction always executes as if it is alone in the system, and in the end its effects are undone (rolled back) if it conflicts with another concurrent transac- tions. In spite of the potential for increasing scalability and performance, TM is a recent and developing programming model and still has a very limited impact in real-world applications.
Designing and developing concurrent software is difficult and error prone. Concur- rent programs exhibit concurrency anomalies that originate faults and failures. Despite some claims that TM programs are less error prone, they still exhibit concurrency anoma- lies such as high-level dataraces, i.e., wrong delimitations of transactions’ scope, and stale-value errors, that occur when the value of a shared variable jumps from an atomic block to another.
Programs with this kind of anomalies can exhibit unpredictable and wrong behaviour, not fulfilling the goals for which they were conceived.
This work aims the detection of anomalies through static analysis of transactional Java ByteCode programs that execute in strong atomicity. A extensible and flexible framework is proposed, which can be extended with plugins that detect specific types of anomalies. With this framework we expect to prove that high-level dataraces and stale-value errors can be detected with reasonable precision through static analysis.

Keywords: Atomicity Violation, High-Level Datarace, Static Analysis, Concurrency, Software Transactional Memory

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Multiheme cytochromes c are important in electron transfer pathways in reduction of both soluble and insoluble Fe(III) by Geobacter sulfurreducens. We determined the crystal structure at 3.2 Å resolution of the first dodecaheme cytochrome c (GSU1996) along with its N-terminal and C-terminal hexaheme fragments at 2.6 and 2.15 Å resolution, respectively. The macroscopic reduction potentials of the full-length protein and its fragments were measured. The sequence of GSU1996 can be divided into four c7-type domains (A, B, C and D) with homology to triheme cytochromes c7. In cytochromes c7 all three hemes are bis–His coordinated, whereas in c7-type domains the last heme is His–Met coordinated. The full-length GSU1996 has a 12 nm long crescent shaped structure with the 12 hemes arranged along a polypeptide to form a “nanowire” of hemes; it has a modular structure. Surprisingly, while the C-terminal half of the protein consists of two separate c7-type domains (C and D) connected by a small linker, the N-terminal half of the protein has two c7-type domains (A and B) that form one structural unit. This is also observed in the AB fragment. There is an unexpected interaction between the hemes at the interface of domains A and B, which form a heme-pair with nearly parallel stacking of their porphyrin rings. The hemes adjacent to each other throughout the protein are within van der Waals distance which enables efficient electron exchange between them. For the first time, the structural details of c7-type domains from one multiheme protein were compared.

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