A formal characterization of SI-based ROWA replication protocols

Snapshot isolation (SI) is commonly used in some commercial DBMSs with a multiversion concurrency control mechanism since it never blocks read-only transactions. Recent database replication protocols have been designed using SI replicas where transactions are firstly executed in a delegate replica and their updates (if any) are propagated to the rest of the replicas at commit time; i.e. they follow the Read One Write All (ROWA) approach. This paper provides a formalization that shows the correctness of abstract protocols which cover these replication proposals. These abstract protocols differ in the properties demanded for achieving a global SI level and those needed for its generalized SI (GSI) variant ¿ allowing reads from old snapshots. Additionally, we propose two more relaxed properties that also ensure a global GSI level. Thus, some applications can further optimize their performance in a replicated system while obtaining GSI. © 2010 Elsevier B.V. All rights reserved.The authors wish to thank the reviewers for their valuable comments that helped us to greatly improve the quality and readability of this paper. This work has been supported by the Spanish Government under research grant TIN2009-14460-C03. Besides, the authors wish to thank the reviewers for their valuable comments that helped us to greatly improve the quality and readability of this paper.Armendáriz-Iñigo, J.; Juárez-Rodríguez, J.; González De Mendívil, J.; Garitagoitia, J.; Irún Briz, L.; Muñoz Escoí, FD. (2011). A formal characterization of SI-based ROWA replication protocols. Data and Knowledge Engineering. 70(1):21-34. doi:10.1016/j.datak.2010.07.012S213470

Endocannabinoids and cardiovascular prevention: real progress?

The prevalence of obesity continues to increase and represents one of the principal causes of cardiovascular morbidity and mortality. After the discovery of a specific receptor of the psychoactive principle of marijuana, the cannabinoid receptors and their endogenous ligands, several studies have demonstrated the role of this system in the control of food intake and energy balance and its overactivity in obesity. Recent studies with the CB1 receptor antagonist rimonabant have demonstrated favorable effects such as a reduction in body weight and waist circumference and an improvement in metabolic factors (cholesterol, triglycerides, glycemia etc). Therefore, the antagonism of the endocannabinoid (EC) system, if recent data can be confirmed, could be a new treatment target for high risk overweight or obese patients. Obesity is a growing problem that has epidemic proportions worldwide and is associated with an increased risk of premature death (1–3). Individuals with a central deposition of fats have elevated cardiovascular morbidity and mortality (including stroke, heart failure and myocardial infarction) and, because of a growing prevalence not only in adults but also in adolescents, it was reclassified in AHA guidelines as a “major modifiable risk factor” for coronary heart disease (4, 5). Although first choice therapy in obesity is based on correcting lifestyle (diet and physical activity) in patients with abdominal obesity and high cardiovascular risk and diabetes, often it is necessary to use drugs which reduce the risks. The EC system represents a new target for weight control and the improvement of lipid and glycemic metabolism (6, 7)