Falcon: On-line monitoring for steering parallel programs

Advances in high performance computing, communications and user interfaces enable developers to construct increasingly interactive high performance applications. The Falcon system presented in this paper supports such interactivity by providing runtime libraries, tools and user interfaces that permit the on-line monitoring and steering of large-scale parallel codes. The principal aspects of Falcon described in this paper are its abstractions and tools for capture and analysis of application-specific program information, performed on-line, with controlled latencies and scalable to parallel machines of substantial size. In addition, Falcon provides support for the on-line graphical display of monitoring information, and it allows programs to be steered during their execution, by human users or algorithmically. This paper presents our basic research motivation, outlines the Falcon system's functionality, and includes a detailed evaluation of its performance characteristics in light of its principal contributions. Falcon's functionality and performance evaluation are driven by our experiences with large-scale parallel applications being developed with end users in physics and in atmospheric sciences. The sample application highlighted in this paper is a molecular dynamics simulation program (MD) used by physicists to study the statistical mechanics of liquids. © 1998 John Wiley & Sons, Ltd.     

Cyclic fatty acids: Separation from straight-chain fatty acids by urea adducting

A mixture containing 37% cyclic and 63% straight-chain fatty acids, made by high-temperature treatment of linseed oil fatty acids with alkali, was separated by the urea adduct method to give unsaturated cyclic fatty acids (nonadduct) in 95% purity and 90–95% yeild. Previous reports from this Laboratory describe a process for separating cyclic fatty acids from stearic acid by hydrogenation followed by crystallization at −40C. The urea adduct method avoids hydrogenation and low-temperature crystallization, and furthermore, unsaturated cyclic and unsaturated straight-chain products can be recovered as individual fractions. Then, by readducting the unsaturated straight-chain fatty acid fraction, the small amounts of palmitic and stearic acids are removed leaving an unsaturated fraction containing oleic, nonconjugated and conjugated linoleic and some unsaturated cyclic fatty acids. Presented at AOCS Meeting, Los Angeles, April 1966. No. Utiliz. Res. Dev. Div., ARS, USDA.     

CTK: configurable object abstractions for multiprocessors

The Configuration Toolkit (CTK) is a library for constructing configurable object based abstractions that are part of multiprocessor programs or operating systems. The library is unique in its exploration of runtime configuration for attaining performance improvements: 1) its programming model facilitates the expression and implementation of program configuration; and 2) its efficient runtime support enables performance improvements by the configuration of program components during their execution. Program configuration is attained without compromising the encapsulation or the reuse of software abstractions. CTK programs are configured using attributes associated with object classes, object instances, state variables, operations, and object invocations. At runtime, such attributes are interpreted by policy classes, which may be varied separately from the abstractions with which they are associated. Using policies and attributes, an object's runtime behavior may be varied by: 1) changing its performance or reliability while preserving the implementation of its functional behavior, or 2) changing the implementation of its internal computational strategy. CTK's multiprocessor implementation is layered on a Cthreads-compatible programming library, which results in its portability to a wide variety of uni- and multiprocessor machines, including a Kendall Square KSR-2 Supercomputer, SGI machines, various SUN workstations, and as a native kernel on the GP1000 BBN Butterfly multiprocessor. The platforms evaluated in the paper are the KSR and SGI machines     

Calibration of neutron albedo dosemeters

It is shown that by calibrating neutron albedo dosemeters under the proper conditions, two complicating effects will essentially cancel out, allowing accurate calibrations with no need for explicit corrections. The 'proper conditions' are: a large room (> or = 8 m on a side). use of a D2O moderated 252Cf source, and a source-to-phantom calibration distance of approximately 70 cm.     

The taxoids. Comparative clinical pharmacology and therapeutic potential

Paclitaxel and docetaxel are 2 compounds from the new taxoid class of anti-cancer agents. Both drugs are very similar in preclinical activity, mechanism of action and spectrum of clinical activity. Some subtle differences in the intracellular retention of docetaxel may account for its lack of schedule-related myelosuppression and greater potency, and may be relevant to the skin toxicity and oedema which it produces. Early data suggest that there may be differing behaviour of anthracycline/taxoid combinations with respect to cardiotoxicity. Paclitaxel has been studied in several first-line combination therapy trials in ovarian cancer. Here, paclitaxel in combination with a platinum compound seems to have proven itself as a standard regimen. It is uncertain if docetaxel will be evaluated in this context. An abundance of clinical data is available for both analogues in the advanced, metastatic setting of breast cancer. Both also have been compared as single agents with doxorubicin with the results suggesting paclitaxel in a 3-hour infusion is inferior to the anthracycline (in terms of response rate), and those of docetaxel suggesting it is superior to the same dose of doxorubicin. This indirect comparison favours the activity of docetaxel; however, it is clear that in the dose/schedules studied, the taxoid compounds are not equitoxic. Either agent by itself, in the treatment of metastatic breast cancer, remains appropriate; however, lack of cumulative toxicity may make paclitaxel more attractive in some situations where prolonged administration is foreseen. Lung cancer trials have also confirmed the activity of both agents, although docetaxel appears to have slightly more promising activity in previously treated patients than paclitaxel. Paclitaxel in combination with cisplatin has been evaluated in randomised trials as first-line treatment of non-small-cell lung cancer (NSCLC). The results of these trials taken together suggest that this combination has an impact on survival similar to other new regimens now considered 'standard' in the front-line setting in this disease. Unfortunately, despite all the phase II data generated in numerous tumour types, little else can be said about the role of either taxoid in the 'standard' management of malignant disease. It will be some years yet before taxoid-based combinations have been evaluated sufficiently in randomised trials such that the impact of this novel class can be adequately assessed in terms of survival and cure rates.