Massively parallel support for a case-based planning system

Case-based planning (CBP), a kind of case-based reasoning, is a technique in which previously generated plans (cases) are stored in memory and can be reused to solve similar planning problems in the future. CBP can save considerable time over generative planning, in which a new plan is produced from scratch. CBP thus offers a potential (heuristic) mechanism for handling intractable problems. One drawback of CBP systems has been the need for a highly structured memory to reduce retrieval times. This approach requires significant domain engineering and complex memory indexing schemes to make these planners efficient. In contrast, our CBP system, CaPER, uses a massively parallel frame-based AI language (PARKA) and can do extremely fast retrieval of complex cases from a large, unindexed memory. The ability to do fast, frequent retrievals has many advantages: indexing is unnecessary; very large case bases can be used; memory can be probed in numerous alternate ways; and queries can be made at several levels, allowing more specific retrieval of stored plans that better fit the target problem with less adaptation. In this paper we describe CaPER's case retrieval techniques and some experimental results showing its good performance, even on large case bases

Countdown to 2010: Can we assess Ireland’s insect species diversity and loss?

peer-reviewedThe insects are the most diverse organisms on this planet and play an essential role in ecosystem functioning, yet we know very little about them. In light of the Convention on Biological Diversity, this paper summarises the known insect species numbers for Ireland and questions whether this is a true refl ection of our insect diversity. The total number of known species for Ireland is 11,422. Using species accumulation curves and a comparison with the British fauna, this study shows that the Irish list is incomplete and that the actual species number is much higher. However, even with a reasonable knowledge of the species in Ireland, insects are such speciose, small, and inconspicuous animals that it is diffi cult to assess species loss. It is impossible to know at one point in time the number of insect species in Ireland and, although it is useful to summarise the known number of species, it is essential that biodiversity indicators, such as the Red List Index, are developed

Superconducting gap variations induced by structural supermodulation in BSCCO

We discuss the possibility that the strain field introduced by the structural supermodulation in Bi-2212 and certain other cuprate materials may modulate the superconducting pairing interaction. We calculate the amplitude of this effect, visible in scanning tunneling spectroscopy experiments, and thereby relate a change in the local superconducting gap with the change in the local dopant displacements induced by the supermodulation. In principle, since this modulation is periodic, sufficiently accurate x-ray measurements or ab initio calculations should enable one to determine which atomic displacements enhance pairing and therefore T_c.Comment: 4 pages, 3 figure

Recent revisions to corporate profits: what we know and when we knew it

Initial estimates in the National Income and Product Accounts significantly overstated U.S. corporate profits for the 1998-2000 period. Subsequent revisions reveal that the profitability of the nation's corporate sector in the late 1990s was substantially weaker than "real-time" data indicated. An unexpected surge in employee stock options exercised-and perhaps, in some sectors, firms' inflated statements of profit-may help explain the large downward revisions.Corporate profits ; Stock options ; Statistics ; Economic indicators

Interaction of Fluorescent Probes with Sirtuin Proteins

Sirtuins are a class of proteins belonging to the Sir2 (Silencing information regulator 2) family of NAD+ dependent protein lysine deacylases. Different Isoforms (SIRT1-SIRT7) differ in their specific deacylase activity and cellular location. They have roles in DNA repair, glucose metabolism, and cellular proliferation which make them highly desirable targets for carcinoma therapeutics. We previously used 1-aminoanthracene’s (AMA) fluorescent properties when bound with SIRT2 (Kd of 37 μM) to develop a high-throughput screen to identify novel ligands that inhibit SIRT2’s enzymatic activities. We hope to reveal other potential probes for future high-throughput screening with all the sirtuin isotopes. 1-AMA’s fluorescence along with fluorescent labeled peptides “Cy3-PEG4-H4K16(myr)” and “FAM-PEG4-H4K16(myr)” were used in binding assays to determine their affinities with SIRT2, SIRT3, and SIRT6. Further, we determined 1-AMA’s ability to bind sirtuin isoforms when they were equilibrated with 100 μM of various acyl-peptides. 1-AMA displays weak binding to SIRT3 and SIRT6 when compared to SIRT2. FAM-PEG4-H4K16(myr) binds SIRT2 with a Kd of 7nM which is much higher than its interaction with SIRT3 and SIRT6 (Kd of 6 μM and 2 μM, respectively). Cy3-PEG4-H4K16(myr) binds as expected SIRT2,3,6 although its affinity for SIRT6 changes minimally with the addition of ADP-ribose, which suggests Cy3 may facilitate binding in the absence of SIRT6’s co-factor. Future work will test additional probes with the other sirtuin proteins and establish their competency to be utilized for high-throughput screening

A transfer function approach for predicting rare cell capture microdevice performance

Rare cells have the potential to improve our understanding of biological systems and the treatment of a variety of diseases; each of those applications requires a different balance of throughput, capture efficiency, and sample purity. Those challenges, coupled with the limited availability of patient samples and the costs of repeated design iterations, motivate the need for a robust set of engineering tools to optimize application-specific geometries. Here, we present a transfer function approach for predicting rare cell capture in microfluidic obstacle arrays. Existing computational fluid dynamics (CFD) tools are limited to simulating a subset of these arrays, owing to computational costs; a transfer function leverages the deterministic nature of cell transport in these arrays, extending limited CFD simulations into larger, more complicated geometries. We show that the transfer function approximation matches a full CFD simulation within 1.34 %, at a 74-fold reduction in computational cost. Taking advantage of these computational savings, we apply the transfer function simulations to simulate reversing array geometries that generate a “notch filter” effect, reducing the collision frequency of cells outside of a specified diameter range. We adapt the transfer function to study the effect of off-design boundary conditions (such as a clogged inlet in a microdevice) on overall performance. Finally, we have validated the transfer function’s predictions for lateral displacement within the array using particle tracking and polystyrene beads in a microdevice.National Cancer Institute (U.S.). Physical Sciences-Oncology Center (Cornell Center on the Microenvironment and Metastasis. Award U54CA143876