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Varying Sizes (varying + size)
Selected AbstractsA Latent Model to Detect Multiple Clusters of Varying SizesBIOMETRICS, Issue 4 2009Minge Xie Summary This article develops a latent model and likelihood-based inference to detect temporal clustering of events. The model mimics typical processes generating the observed data. We apply model selection techniques to determine the number of clusters, and develop likelihood inference and a Monte Carlo expectation,maximization algorithm to estimate model parameters, detect clusters, and identify cluster locations. Our method differs from the classical scan statistic in that we can simultaneously detect multiple clusters of varying sizes. We illustrate the methodology with two real data applications and evaluate its efficiency through simulation studies. For the typical data-generating process, our methodology is more efficient than a competing procedure that relies on least squares. [source] Enhancing the oral bioavailability of the poorly soluble drug dicumarol with a bioadhesive polymerJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2003Chris G. Thanos Abstract This article investigates the effect of particle size and the incorporation of a bioadhesive polymer, poly(fumaric- co -sebacic) anhydride p(FA:SA), on the relative bioavailability of dicumarol. A novel method was used to reduce particle size of the drug, and encapsulated formulations were fabricated using a phase inversion technique to produce nanospheres and microspheres with varying size. Groups of Yorkshire swine were catheterized and gavaged after fasting for 12 h with each formulation in a 50 mg/mL suspension. Blood was collected at different time points, from 0 to 96 h, and pharmacokinetic analysis revealed that formulations incorporating the smaller drug particles showed the highest bioavailability: micronized drug with 7% p(FA:SA) 17:83 polymer had 190% relative bioavailability, and phase inverted p(FA:SA) 17:83 microspheres with 31% (w/w) loading had 198% relative bioavailability to spray dried formulation. Formulations with larger drug particles achieved 71% relative bioavailability. A nonadhesive formulation, fabricated with poly(lactic acid) (PLA), showed 91% relative bioavailability. Both particle size and polymer composition play a role in oral absorption of dicumarol. © 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:1677,1689, 2003 [source] Ambient Template-Directed Synthesis of Single-Crystalline Alkaline-Earth Metal Fluoride Nanowires,ADVANCED MATERIALS, Issue 14 2006Y. Mao A facile and mild means of controllably preparing a series of single-crystalline alkaline-earth metal fluoride nanowires of reproducible shape and varying sizes (see figure) using a simple, room-temperature approach has been developed. This approach is based on the use of readily commercially available polycarbonate template membranes. The favorable luminescence properties of the doped nanowires imply their possible incorporation into functional nanoscale devices. [source] Proper Assessment of the JFK Assassination Bullet Lead Evidence from Metallurgical and Statistical PerspectivesJOURNAL OF FORENSIC SCIENCES, Issue 4 2006Erik Randich Ph.D. ABSTRACT: The bullet evidence in the JFK assassination investigation was reexamined from metallurgical and statistical standpoints. The questioned specimens are comprised of soft lead, possibly from full-metal-jacketed Mannlicher-Carcano (MC), 6.5-mm ammunition. During lead refining, contaminant elements are removed to specified levels for a desired alloy or composition. Microsegregation of trace and minor elements during lead casting and processing can account for the experimental variabilities measured in various evidentiary and comparison samples by laboratory analysts. Thus, elevated concentrations of antimony and copper at crystallographic grain boundaries, the widely varying sizes of grains in MC bullet lead, and the 5,60 mg bullet samples analyzed for assassination intelligence effectively resulted in operational sampling error for the analyses. This deficiency was not considered in the original data interpretation and resulted in an invalid conclusion in favor of the single-bullet theory of the assassination. Alternate statistical calculations, based on the historic analytical data, incorporating weighted averaging and propagation of experimental uncertainties also considerably weaken support for the single-bullet theory. In effect, this assessment of the material composition of the lead specimens from the assassination concludes that the extant evidence is consistent with any number between two and five rounds fired in Dealey Plaza during the shooting. [source] Recipe determination and scheduling of gasoline blending operationsAICHE JOURNAL, Issue 2 2010Jie Li Abstract Gasoline is a major contributor to the profit of a refinery. Scheduling gasoline-blending operations is a critical and complex routine task involving tank allocation, component mixing, blending, product storage, and order delivery. Optimized schedules can maximize profit by avoiding ship demurrage, improving order delivery, minimizing quality give-aways, avoiding costly transitions and slop generation, and reducing inventory costs. However, the blending recipe and scheduling decisions make this problem a nonconvex mixed-integer nonlinear program (MINLP). In this article, we develop a slot-based MILP formulation for an integrated treatment of recipe, specifications, blending, and storage and incorporate many real-life features such as multipurpose product tanks, parallel nonidentical blenders, minimum run lengths, changeovers, piecewise constant profiles for blend component qualities and feed rates, etc. To ensure constant blending rates during a run, we develop a novel and efficient procedure that solves successive MILPs instead of a nonconvex MINLP. We use 14 examples with varying sizes and features to illustrate the superiority and effectiveness of our formulation and solution approach. The results show that our solution approach is superior to commercial solvers (BARON and DICOPT). © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] | ||||||||||