The Origin, Early Evolution and Predictability of Solar Eruptions

Coronal mass ejections (CMEs) were discovered in the early 1970s when space-borne coronagraphs revealed that eruptions of plasma are ejected from the Sun. Today, it is known that the Sun produces eruptive flares, filament eruptions, coronal mass ejections and failed eruptions; all thought to be due to a release of energy stored in the coronal magnetic field during its drastic reconfiguration. This review discusses the observations and physical mechanisms behind this eruptive activity, with a view to making an assessment of the current capability of forecasting these events for space weather risk and impact mitigation. Whilst a wealth of observations exist, and detailed models have been developed, there still exists a need to draw these approaches together. In particular more realistic models are encouraged in order to asses the full range of complexity of the solar atmosphere and the criteria for which an eruption is formed. From the observational side, a more detailed understanding of the role of photospheric flows and reconnection is needed in order to identify the evolutionary path that ultimately means a magnetic structure will erupt

Antiplatelet action of 3 ',4 '-diisovalerylkhellactone diester purified from Peucedanum japonicum Thunb

3',4'-Diisovalerylkhellactone diester (PJ-1) is a coumarin derivative purified from the medicinal herb Peucedanum japonicum Thunb, We examined its in vitro effects on various aspects of platelet reactivity, PJ-1 inhibited the aggregation and ATP release of rabbit platelets induced by PAF (platelet-activating factor) and collagen, The IC,, values of PJ-1 and BN52021 on PAF (2 ng/ml)-induced platelet aggregation were about 56.3 and 22.0 mu M, respectively, And, the IC50 value of PJ-1 toward collagen (10 mu g/ml)-induced platelet aggregation was 89.4 mu M. Although the platelet aggregation caused by arachidonic acid and thrombin were barely inhibited by PJ-1, the release reactions were partially suppressed. PJ-1 also inhibited the thromboxane B-2 formation caused by collagen, while formations of thromboxane B-2 and prostaglandin D-2 caused by arachidonic acid were not affected. The phosphoinositide breakdown caused by PAF was inhibited by PJ-1, but those by other inducers were not affected significantly. PJ-1 inhibited the intracellular Ca2+ increase caused by PAF in fura-2-loaded platelets. PJ-1 also concentration-dependently inhibited [H-3]PAF (3.03 ng/ml) binding to washed platelets with an IC,, value of 3.9 mu M. It is concluded that the main antiplatelet effect of PJ-1 may be due to dual activities on the blockade of PAF receptor-induced activation and also the inhibition of phospholipase A(2) in rabbit platelets

An expressive and efficient solution to the service selection problem

Abstract. Given the large number of Semantic Web Services that can be created from online sources by using existing annotation tools, expressive formalisms and efficient and scalable approaches to solve the service selection problem are required to make these services widely available to the users. In this paper, we propose a framework that is grounded on logic and the Local-As-View approach for representing instances of the service selection problem. In our approach, Web services are semantically described using LAV mappings in terms of generic concepts from an ontology, user requests correspond to conjunctive queries on the generic concepts and, in addition, the user may specify a set of preferences that are used to rank the possible solutions to the given request. The LAV formulation allows us to cast the service selection problem as a query rewriting problem that must consider the relationships among the concepts in the ontology and the ranks induced by the preferences. Then, building on related work, we devise an encoding of the resulting query rewriting problem as a logical theory whose models are in correspondence with the solutions of the user request, and in presence of preferences, whose best models are in correspondence with the best-ranked solutions. Thus, by exploiting known properties of modern SAT solvers, we provide an efficient and scalable solution to the service selection problem. The approach provides the basis to represent a large number of real-world situations and interesting user requests.