We characterize the class $CG(s)$ of matrices A for which the linear system $A{\bf x} = {\bf b}$ can be solved by an s-term conjugate gradient method. We show that, except for a few anomalies, the class $CG(s)$ consis...
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We characterize the class $CG(s)$ of matrices A for which the linear system $A{\bf x} = {\bf b}$ can be solved by an s-term conjugate gradient method. We show that, except for a few anomalies, the class $CG(s)$ consists of matrices A for which conjugate gradient methods are already known. These matrices are the Hermitian matrices, $A^ *= A$, and the matrices of the form $Ae^{i\theta} (dI + B)$, with $B^ *= - B$.
Understanding mechanisms that regulate when, where and how flowers are formed would elucidate cell-fate determination in plants. Some of the advances made towards deciphering genes controlling floral induction, merist...
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Understanding mechanisms that regulate when, where and how flowers are formed would elucidate cell-fate determination in plants. Some of the advances made towards deciphering genes controlling floral induction, meristem specification and floral organ patterning are reviewed here. Studies beginning in the early 1980s of mutations in Arabidopsis thaliana of Antirrhinum majus that alter either floral induction or floral meristem fate or floral organ fate were start points for these analyses. Cloning and functional characterization of the corresponding genes has illustrated how transcription factors of the MADS box gene-family or factors involved in cell-cell signalling regulate cell fate. These studies reveal evolutionarily conserved elements in the flower development pathway.
Clusters of symmetric shared memory multiprocessors (SMPs) are fast becoming a highly available platform for parallel computing. There is a need for a uniform programming paradigm that allows users to transparently ex...
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Clusters of symmetric shared memory multiprocessors (SMPs) are fast becoming a highly available platform for parallel computing. There is a need for a uniform programming paradigm that allows users to transparently extend parallelism across multiple SMP nodes. A shared memory paradigm leverages the available hardware to handle sharing within an SMP, in addition to providing programming ease. Software distributed shared memory systems support the illusion of shared memory across the cluster via a software runtime layer between the application and the hardware. This approach can potentially provide a cost-effective alternative to larger hardware shared memory systems for executing certain classes of workloads. We describe here one such system and discuss its interface, performance and portability through an example real-world application from the scientific domain.
With the introduction of Web Real-Time Communications (WebRTC), both Web technology and RTC have entered a new era. WebRTC is a joint effort of the W3C and IETF, supported by a large industry consortium. The technolog...
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With the introduction of Web Real-Time Communications (WebRTC), both Web technology and RTC have entered a new era. WebRTC is a joint effort of the W3C and IETF, supported by a large industry consortium. The technology offers real-time, peer-to-peer communication capabilities directly in the user's browser, accessible to websites via JavaScript APIs. Because of the numerous potential applications and the accessibility of the technology, WebRTC is expected to quickly become a game-changing technology in the communication landscape.
Performance monitor (PM) support in on-chip PowerPC(R) microprocessors is used to analyze processor, software, and system attributes for a variety of workloads. The interface to the PowerPC 604(R) microprocessor, whic...
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Performance monitor (PM) support in on-chip PowerPC(R) microprocessors is used to analyze processor, software, and system attributes for a variety of workloads. The interface to the PowerPC 604(R) microprocessor, which we abbreviate ''604,'' has been externalized to end users. We discuss the enhanced PM support available in an upgrade of the 604, the PowerPC 604e(TM) microprocessor, which we abbreviate ''604e.'' We discuss the challenges related to the externalization of the PM support as it relates to other PowerPC processors not derived from the 604 and briefly contrast these PMs with other PMs. We also describe an applicationprogramming interface (API) to the on-chip PM support, its design methodology, and its usage considerations, intended to meet these challenges.
The complete peptide map of purified recombinant human interleukin 5 (rhIL-5) was determined to verify its primary structure, glycosylation sites, and disulfide bonding structure. Each peptide fragment generated by Ac...
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The complete peptide map of purified recombinant human interleukin 5 (rhIL-5) was determined to verify its primary structure, glycosylation sites, and disulfide bonding structure. Each peptide fragment generated by Achromobacter protease I (API) digestion was purified and characterized by amino acid analysis and amion acid sequence analysis. After digestion with API, we could identify all the peptides which were expected from human IL-5 cDNA sequence. The analyses of sulfhydryl content in rhIL-5 molecule and disulfide-containing peptide obtained from API digestion indicated that active form of rhIL-5 existed as an antiparallel dimer linked by two pairs of Cys-44 and Cys-86. In addition, we concluded that Thr-3 and Asn-28 were glycosylated. The results indicate that primary structure of rhIL-5 is highly homogeneous and observed heterogeneity is due to the difference in the content of carbohydrate.
The enterotoxigenicty of 12 coliform strains (Enterobacter cloacae, Klebsiella pneumoniae and Escherichia coli) isolated from the gastrointestinal (GI) tract of persons with acute diarrhea or tropical sprue and of 13 ...
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The enterotoxigenicty of 12 coliform strains (Enterobacter cloacae, Klebsiella pneumoniae and Escherichia coli) isolated from the gastrointestinal (GI) tract of persons with acute diarrhea or tropical sprue and of 13 strains of the same species isolated from urine (GU) cultures was determined. Fractions of heat-labile (LT) and heat-stable (ST) toxins of each strain were separated by ultrafiltration, and the effect of graded concentrations (range, 100 .mu.g-10 pg/ml) on water transport was assessed by in vivo perfusion in the rat jejunum. Enterotoxigenic activity was defined as inducement of net secretion of water. All 12 of the GI strains and 6 of 13 GU strains elaborated enterotoxins, but there was a millionfold quantitative difference in the potency of the toxins produced. All GI strains produced 1 or both forms of toxin, which had a minimal effective concentration of as low as 0.1-10 ng/ml;GU strains produced toxins of weak or, rarely, intermediate potency.
The complexity of real-time systems is growing extremely rapidly, as they move from isolated devices to multilevel networked systems. Traditional methodologies for developing and managing these systems are not scaling...
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The complexity of real-time systems is growing extremely rapidly, as they move from isolated devices to multilevel networked systems. Traditional methodologies for developing and managing these systems are not scaling to meet the requirements of a new generation of distributed applications. While developers of complex real-time applications are looking to service-oriented architecture to address their needs for ease of development and flexibility of integration, current software infrastructures for service-oriented applications do not address the issue of predictable latency for the applications they host. in this paper, we present Pulsar, a resource-control architecture for managing the end-to-end latency of a set of distributed, time-critical applications. The primary entity of Pulsar is called a controller, which regulates an aspect of resource allocation or scheduling policy. Controllers utilize policy configurations, which may include latency targets to be achieved or resource allocations to be honored, and interact with resource allocators and schedulers (e.g., thread schedulers, memory allocators, or bandwidth reservation mechanisms) to effect local policy. Controllers also provide feedback on how well they are executing a policy. Pulsar includes an application model which captures resource-sensitive behavior and requirements and is independent of high-level programming models and application programming interfaces.
A. N. Kolmogorov and A. Renyi both presuppose a Boolean algebra in their accounts of an absolute probability space, but Karl Popper does not. A review of the accounts of an absolute probability space put forward b...
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A. N. Kolmogorov and A. Renyi both presuppose a Boolean algebra in their accounts of an absolute probability space, but Karl Popper does not. A review of the accounts of an absolute probability space put forward by Kolmogorov, Renyi and Popper is offered.
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