A Unique Opportunity for an Intercultural Discussion on CAM and Liver Disease: APASL, Asian Pacific Association for the Study of the Liver, December 2004, New Delhi, India

The meeting of the APASL, Asian Pacific Association for the Study of the Liver, was held in December 2004, in New Delhi, India. The meeting was held under the patronage of the APASL Committee and Board of Presidents of the National Liver Association and in conjunction with the annual conference of the Indian Association for the Study of Liver (INASL). The congress was designed to have a core meeting with three parallel sessions running throughout, dedicated research workshops and intensive breakfast sessions. This report concentrates on the two sessions devoted to complementary and alternative medicine (CAM) and shows the latest research in CAM for liver disease and the concerns of doctors about integrating CAM with more traditional treatments. With researchers and practitioners gathering from all over the world, it was a unique opportunity for an intercultural discussion on CAM and liver disease

A Conflict-Resilient Lock-Free Calendar Queue for Scalable Share-Everything PDES Platforms

Emerging share-everything Parallel Discrete Event Simulation (PDES) platforms rely on worker threads fully sharing the workload of events to be processed. These platforms require efficient event pool data structures enabling high concurrency of extraction/insertion operations. Non-blocking event pool algorithms are raising as promising solutions for this problem. However, the classical non-blocking paradigm leads concurrent conflicting operations, acting on a same portion of the event pool data structure, to abort and then retry. In this article we present a conflict-resilient non-blocking calendar queue that enables conflicting dequeue operations, concurrently attempting to extract the minimum element, to survive, thus improving the level of scalability of accesses to the hot portion of the data structure---namely the bucket to which the current locality of the events to be processed is bound. We have integrated our solution within an open source share-everything PDES platform and report the results of an experimental analysis of the proposed concurrent data structure compared to some literature solutions

Evaluation of biodegradation kinetic constants for aromatic compounds by means of aerobic batch experiments

Kinetics of aerobic biodegradation have been investigated for twenty aromatic species using sludges collected from the aeration basin of municipal sewage treatment plants. The reproducibility of the results is tested with respect to the sludges period of collection and the wastewater treatment plant where they are taken. The comparison of kinetic constants, estimated for the investigated chemicals, allows to evaluate the reactivity effect of single groups (i.e., -OH, -CH3, -Cl, -NO2) into the aromatic structures. The search for easy structure-reactivity relationships is also attempted by means of contributing group methods

A Non-Blocking Priority Queue for the Pending Event Set

The large diffusion of shared-memory multi-core machines has impacted the way Parallel Discrete Event Simulation (PDES) engines are built. While they were originally conceived as data-partitioned platforms, where each thread is in charge of managing a subset of simulation objects, nowadays the trend is to shift towards share-everything settings. In this scenario, any thread can (in principle) take care of CPU-dispatching pending events bound to whichever simulation object, which helps to fully share the load across the available CPU-cores. Hence, a fundamental aspect to be tackled is to provide an efficient globally-shared pending events’ set from which multiple worker threads can concurrently extract events to be processed, and into which they can concurrently insert new produced events to be processed in the future. To cope with this aspect, we present the design and implementation of a concurrent non-blocking pending events’ set data structure, which can be seen as a variant of a classical calendar queue. Early experimental data collected with a synthetic stress test are reported, showing excellent scalability of our proposal on a machine equipped with 32 CPU-cores

A Non-blocking Buddy System for Scalable Memory Allocation on Multi-core Machines

Common implementations of core memory allocation components handle concurrent allocation/release requests by synchronizing threads via spin-locks. This approach is not prone to scale with large thread counts, a problem that has been addressed in the literature by introducing layered allocation services or replicating the core allocators - the bottom most ones within the layered architecture. Both these solutions tend to reduce the pressure of actual concurrent accesses to each individual core allocator. In this article we explore an alternative approach to scalability of memory allocation/release, which can be still combined with those literature proposals. We present a fully non-blocking buddy-system, that allows threads to proceed in parallel, and commit their allocations/releases unless a conflict is materialized while handling its metadata. Beyond improving scalability and performance it is resilient to performance degradation in face of concurrent accesses independently of the current level of fragmentation of the handled memory blocks

Optimizing simulation on shared-memory platforms: The smart cities case

Modern advancements in computing architectures have been accompanied by new emergent paradigms to run Parallel Discrete Event Simulation models efficiently. Indeed, many new paradigms to effectively use the available underlying hardware have been proposed in the literature. Among these, the Share-Everything paradigm tackles massively-parallel shared-memory machines, in order to support speculative simulation by taking into account the limits and benefits related to this family of architectures. Previous results have shown how this paradigm outperforms traditional speculative strategies (such as data-separated Time Warp systems) whenever the granularity of executed events is small. In this paper, we show performance implications of this simulation-engine organization when the simulation models have a variable granularity. To this end, we have selected a traffic model, tailored for smart cities-oriented simulation. Our assessment illustrates the effects of the various tuning parameters related to the approach, opening to a higher understanding of this innovative paradigm

NBBS: A Non-blocking Buddy System for Multi-core Machines

Common implementations of core memory allocation components, like the Linux buddy system, handle concurrent allocation/release requests by synchronizing threads via spinlocks. This approach is not prone to scale with large thread counts, a problem that has been addressed in the literature by introducing layered allocation services or replicating the core allocators—the bottom most ones within the layered architecture. Both these solutions tend to reduce the pressure of actual concurrent accesses to each individual core allocator. In this article we explore an alternative approach to scalability of memory allocation/release, which can be still combined with those literature proposals. We present a fully non-blocking buddy-system, where threads performing concurrent allocations/releases do not undergo any spinlock based synchronization. Our solution allows threads to proceed in parallel, and commit their allocations/releases unless a conflict is materialized while handling its metadata. Conflict detection relies on conventional atomic machine instructions in the Read-Modify-Write (RMW) class. Beyond improving scalability and performance, our solution can also avoid wasting clock cycles for spin-lock operations by threads that could in principle carry out their memory allocation/release in full concurrency. Thus, it is resilient to performance degradation—in face of concurrent accesses—independently of the current level of fragmentation of the handled memory blocks

Twisted CFT and bilayer Quantum Hall systems

We identify the impurity interactions of the recently proposed CFT description of a bilayer Quantum Hall system at filling nu =m/(pm+2) in Mod. Phys. Lett. A 15 (2000) 1679. Such a CFT is obtained by m-reduction on the one layer system, with a resulting pairing symmetry and presence of quasi-holes. For the m=2 case boundary terms are shown to describe an impurity interaction which allows for a localized tunnel of the Kondo problem type. The presence of an anomalous fixed point is evidenced at finite coupling which is unstable with respect to unbalance and flows to a vacuum state with no quasi-holes.Comment: 15 pages, 1 figure, Late