A Concurrent Tuple Set Architecture for Call Level Interfaces

Call Level Interfaces (CLI) are low level API aimed at providing services to connect two main components in database applications: client applications and relational databases. Among their functionalities, the ability to manage data retrieved from databases is emphasized. The retrieved data is kept in local memory structures that may be permanently connected to the host database. Client applications, beyond the ability to read their contents, may also execute Insert, Update and Delete actions over the local memory structures, following specific protocols. These protocols are row (tuple) oriented and, while being executed, cannot be preempted to start another protocol. This restriction leads to several difficulties when applications need to deal with several tuples at a time. The most paradigmatic case is the impossibility to cope with concurrent environments where several threads need to access to the same local memory structure instance, each one pointing to a different tuple and executing its particular protocol. To overcome the aforementioned fragility, a Concurrent Tuple Set Architecture (CTSA) is proposed to manage local memory structures. A performance assessment of a Java component based on JDBC (CLI) is also carried out and compared with a common approach. The main outcome of this research is the evidence that in concurrent environments, components relying on the CTSA may significantly improve the overall performance when compared with solutions based on standard JDBC API.(undefined

Optimizing decomposition of software architecture for local recovery

Cataloged from PDF version of article.The increasing size and complexity of software systems has led to an amplified number of potential failures and as such makes it harder to ensure software reliability. Since it is usually hard to prevent all the failures, fault tolerance techniques have become more important. An essential element of fault tolerance is the recovery from failures. Local recovery is an effective approach whereby only the erroneous parts of the system are recovered while the other parts remain available. For achieving local recovery, the architecture needs to be decomposed into separate units that can be recovered in isolation. Usually, there are many different alternative ways to decompose the system into recoverable units. It appears that each of these decomposition alternatives performs differently with respect to availability and performance metrics. We propose a systematic approach dedicated to optimizing the decomposition of software architecture for local recovery. The approach provides systematic guidelines to depict the design space of the possible decomposition alternatives, to reduce the design space with respect to domain and stakeholder constraints and to balance the feasible alternatives with respect to availability and performance. The approach is supported by an integrated set of tools and illustrated for the open-source MPlayer software

Seroprevalence of hepatitis a infection in the Turkish Republic of Northern Cyprus

This study was conducted to determine the seroprevalence of hepatitis A virus (HAV) infection in the Turkish Republic of Northern Cyprus. Materials and Methods: A total of 660 unvaccinated persons 1 to 30 years old were selected for the study with cluster sampling. Information on sociodemographic characteristics was gathered for each participant and, in 641 of them, anti-HAV antibodies were assayed using an enzyme immune assay. Results: Anti-HAV prevalence in the Turkish population under the age of 30 in Northern Cyprus was 23.9%. For the age groups 1-5, 6-10 and 11-15 years, seroprevalence rates were relatively low (11.4, 9.4 and 12%, respectively). For age groups 16 years and over, HAV seroprevalence gradually increased with age, rising to 30.4% in 16 to 20 years and to 52.5% in 21 to 30 years of age. In addition to age, other variables significantly associated with HAV seroprevalence included low family income, family size, waste water sewage, and the education level of parents. Conclusions: Anti-HAV seroprevalence in the Turkish Republic of Northern Cyprus shows an intermediate prevalence. As well as expanding health education and improving sanitation, a hepatitis A universal mass vaccination program would be logical for the population. © TÜBITAK

Retinol and ?-tocopherol concentrations in breast milk of Turkish lactating mothers under different socio-economic status

PubMed ID: 17852471Retinol and ?-tocopherol levels in breast milk of Turkish mothers under different socio-economic status were investigated. Mature milk samples were collected from 92 lactating mothers living in Izmir and in Manisa, cities of Turkey, who were at 60-90 days of the lactating period. Socio-economic, anthropometric, and dietary data were collected by means of a questionnaire. The body mass index was used to determine the nutritional status. The retinol and ?-tocopherol contents of breast milk were determined by high-performance liquid chromatography; the concentration of ?-tocopherol was 9.84 µg/ml whereas retinol levels were 81.5 µg/100 ml. The questionnaire survey was used to determine the level of these vitamins in the daily ration of the women. No significant differences were found in terms of milk retinol and ?-tocopherol levels for the variables income, educational level and mothers' body mass index.Assumption College Celal Bayar ÜniversitesiThe authors thank the Celal Bayar University Research Fund for their financial support and thank the AC¸ SAP (Mother and Infant Health Planning) Centers in İzmir and Manisa for kind help with the supply of human milk samples. -