A parallel algorithm for diffusion-limited aggregation (DLA) is described and analyzed from the perspective of computational complexity. The dynamic exponent z of the algorithm is defined with respect to the PRAM model of parallel computation according to T ∼ L z , where T is the running time and L the cluster size. It is argued that z = D − D 2 /3, where D is the fractal dimension and D 2 is t...

In this paper we present the results of a practical exercise in matching records from two different legacy databases. This exercise is a portion of our work for the US Defense Logistics Agency, (DLA). It addresses the problem of identifying parts in the database of DLA managed items that match parts available from a commercial online catalog. A method of automatically generating approximate mat...

The High Energy Transmission Grating (HETG) Spectrometer on the Advanced X-ray Astrophysics Facility (AXAF) (scheduled for launch in August, 1998) will provide a new tool for the study of absorption in the X-ray spectra of high redshift quasars due to the material along the line of sight. In this paper we try to explore the possibility of using AXAF HETG to detect resonance absorption lines fro...

PURPOSE To investigate the relationship between neuroretinal rim (NRR) differential light absorption (DLA, a measure of spectral absorption properties) and visual field (VF) sensitivity in primary open-angle glaucoma (POAG). METHODS Patients diagnosed with (n = 22) or suspected of having (n = 7) POAG were imaged with a multispectral system incorporating a modified digital fundus camera, 250-W...

BACKGROUND Despite widespread clinical uses of resin-modified glass-ionomers (RMGIs), their sealing ability is still a concern. This study evaluated the effect of delayed light activation (DLA) of RMGI on marginal sealing in differently pretreated cavities. MATERIALS AND METHODS In this in vitro study, two standardized Class V cavities were prepared on the buccal and lingual surfaces of 56 so...

Growth processes occurring far from equilibrium are widespread in nature and technology. Examples include electrodeposition [1], viscous fingering [2], bacterial colonies [3], and neurite formation [4]. Computer models for the growth of clusters, generally constituted of identical particles, are useful tools for the understanding of aggregation phenomena. The main contribution of such models is...

Chronic hepatitis (CH) is common in dogs in the United Kingdom. An increased prevalence of the disease is seen in the English Springer spaniel (ESS), and this breed suffer from a severe form with young to middle aged female dogs being predisposed. The disease shares histological features with those of human viral hepatitis, although the specific aetiological agent has not yet been identified. T...

We present the first theoretical study of metals in damped-Lyα (DLA) systems at redshift z ≃ 7. The features of cold, primordial gas are studied by means of N-body, hydro, chemistry simulations, including atomic and molecular non-equilibrium chemistry, cooling, star formation for population III and population II-I regimes, stellar evolution, cosmic metal spreading according to proper yields (fo...

High redshift DLA systems suggest that the relative abundances of elements might be roughly solar, although with absolute abundances of more than two orders of magnitude below solar. The result comes from observations of the [SII/ZnII] ratio, which is a reliable diagnostic of the true abundance, and from DLA absorbers with small dust depletion and negligible HII contamination. In particular, in...

The growth of a diffusion limited aggregation (DLA) cluster with mass M and radius of gyration R is described by a set of growth probabilities {pi}, where pi is the probability that the perimeter site i will be the next to grow. We introduce the joint distribution N(α, x,M), where N(α, x,M)dαdx is the number of perimeter sites with α-values in the range α ≤ αi ≤ α + dα (“αsites”) and located in...