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<p> A mixture distribution is a compounding of statistical distributions, which arises when sampling from heterogeneous populations with a different probability density function in each component. A finite mixture has a finite number of components. In the past decade the extent and the potential of the applications of finite mixture models have widened considerably.</p> <p> The objective of this project is to add some functionalities to a package 'mixdist' developed by Du and Macdonald (Du 2002) and Gao (2004) in the R environment (R Development Core Team 2004) for estimating the parameters of a finite mixture distribution with data grouped in bins and conditional data. Mixed data together with conditional data will provide better estimates of parameters than do mixed data alone. Our main objective is to obtain the optimal sample size for each bin of the mixed data to obtain conditional data, given approximate values of parameters and the distributional form of the mixture for the given data. We have also replaced the dependence of the function mix upon the optimizer nlm to optimizer optim to provide the limits to the parameters.</p> <p> Our purpose is to provide easily available tools to modeling fish growth using mixture distribution. However, it has a number of applications in other areas as well.</p> / Thesis / Master of Science (MSc)

The high density lipoprotein (HDL) receptor Scavenger Receptor, Class B, Type I (SRBI) is a 509 amino acid integral membrane protein which has been shown to have an important role in HDL-mediated reverse cholesterol transport. SR-BI has been shown to mediate selective uptake of cholesterol, and also mediates efflux of cholesterol to HDL as seen in in vitro cell culture studies. SR-BI is abundant in the liver and steroidogenic tissues, and is also present in macrophages, which play an important role in the initial stages of atherosclerotic development. SR-BI has been shown to be protective against atherosclerosis by way of overexpression and knockout (KO) studies in murine atherosclerosis models, including low density lipoprotein receptor (LDLR) knockout mice, apolipoprotein E (ApoE) knockout mice, and human apolipoprotein B (ApoB) transgenic mice. SR-BI/LDLR double knockout (dKO) mice show a 6-fold increase in diet-induced atherosclerosis compared to LDLR single KO controls, and SR-BI/ApoE dKO mice show severe coronary occlusion, myocardial infarction, and premature death on a normal chow diet. In both, plasma total cholesterol levels are significantly elevated, and associated with abnormally large HDL particles. The majority ofSR-BI's atheroprotective effect has been shown to result from plasma cholesterol clearance by way of selective uptake in the liver. Recently, Covey et al showed that elimination of SRBI expression in macrophages of LDLR KO mice resulted in increased diet-induced atherosclerosis. To see if SR-BI in macrophages contributes to the overall atheroprotective effect of SR-BI in ApoE KO mice, presumably by mediating cellular cholesterol efflux to HDL, selective deletion ofSR-BI was induced in bone marrow derived cells of ApoE KO mice using bone marrow transplantation. Female ApoE -/recipient mice were transplanted with either SR-BI +/+ ApoE -/-or SR-BI -/- ApoE -/bone marrow from male donor mice, and fed a high fat diet for 12 weeks. This resulted in significantly increased atherosclerosis in mice transplanted with SR-BI -/- ApoE -/-bone marrow, with a concomitant decrease in cholesterol associated with HDL-sized lipoproteins. No significant differences were seen in plasma total cholesterol levels or levels of cholesterol associated with non-HDL lipoproteins. These data suggest that SRBI in macrophages contributes to SR-BI's overall protective effect against atherosclerosis, and also plays a role in the regulation ofHDL cholesterol, in ApoE deficient mice. / Thesis / Master of Science (MSc)

Metal organic frameworks (MOFs) are nanoporous materials composed of inorganic and organic structural building units (SBUs). Over the last several decades, interest in MOFs has grown considerably partially due to their promising capabilities for carbon capture and storage (CCS) technologies. This is mostly due to their tunable pore chemistry, high internal surface area and unique structural diversity. This thesis focuses on computational methods that were used to analyze and organize a database of hypothetical structures to facilitate MOF discovery. The work done is detailed in two main parts. In the first part of the thesis, a topologically diverse hypothetical MOF database, containing over 300,000 structures, is screened using simplified molecular-input line-entry system (SMILES) strings to identify SBUs in each structure. The structures in the database are then renamed according to the SBUs identified by the SMILES strings algorithm. The renaming of the structures allows users to have a good idea of the geometrical and topological distribution of the database. Furthermore, a quick and reliable test is developed to identify structures with incorrect bonding patterns/missing hydrogen. In the second part of the thesis, density functional theory (DFT) - derived charges are generated for each structure in the hypothetical MOF database. Using these charges, the CO₂/N₂ selectivity is calculated and compared with the selectivity values obtained from another charge generating method, split-charge equilibration (SQE), and it is determined that there is good agreement, r = 0.96, between the two methods. A machine learning model is then developed to identify relationships between geometrical features and CO₂/N₂ selectivity.

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Bibliography: leaves 31-32. / by Kin C. Yu. / M.S.

Yes / Sedimentation processes are fundamental to solids/liquid separation in water and wastewater treatment, and therefore a robust understanding of the settlement characteristics of mass fractal aggregates (flocs) formed in the flocculation stage is fundamental to optimized settlement tank design and operation. However, the use of settling as a technique to determine aggregates’ traits is limited by current understanding of permeability. In this paper, we combine experimental and numerical approaches to assess settling velocities of fractal aggregates. Using a non-intrusive in situ digital image-based method, three- and two-dimensional fractal dimensions were calculated for kaolin-based flocs. By considering shape and fractal dimension, the porosity, density and settling velocities of the flocs were calculated individually, and settling velocities compared with those of spheres of the same density using Stokes’ law. Shape analysis shows that the settling velocities for fractal aggregates may be greater or less than those for perfect spheres. For example, fractal aggregates with floc fractal dimension, Df ¼ 2.61, floc size, df > 320 μm and dp ¼ 7.5 μm settle with lower velocities than those predicted by Stokes’ law; whilst, for Df ¼ 2.33, all aggregates of df > 70 μm and dp ¼ 7.5 μm settled below the velocity calculated by Stokes’ law for spheres. Conversely, fractal settling velocities were higher than spheres for all the range of sizes, when Df of 2.83 was simulated. The ratio of fractal aggregate to sphere settling velocity (the former being obtained from fractal porosity and density considerations), varied from 0.16 to 4.11 for aggregates in the range of 10 and 1,000 μm, primary particle size of 7.5 μm and a three-dimensional fractal dimension between 2.33 and 2.83. However, the ratio decreases to the range of 0.04–2.92 when primary particle size changes to 1.0 μm for the same fractal dimensions. Using the floc analysis technique developed here, the results demonstrate the difference in settlement behaviour between the approach developed here and the traditional Stokes’ law approach using solid spheres. The technique and results demonstrate the improvements in understanding, and hence value to be derived, from an analysis based on fractal, rather than Euclidean, geometry when considering flocculation and subsequent clarification performance / Rodrigo B. Moruzzi is grateful to São Paulo Research Foundation (Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP) Grant 2017/19195-7 for financial support and to CNPq for the fellowship Grant 301210/2018-7.

yes / Highlights: Non-additive probabilities and Choquet integrals in a classical context. The use of Choquet integrals in a quantum context. Approximation of partially known density matrices with Choquet integrals.

The temperature-density equation of Kinetic Theory and the conservative neutron transport equation are studied. In both cases a modified version of the Larsen-Habetler resolvent integration technique is applied to obtain full-range and half-range expansions. For the neutron transport equation the method applied is seen to have notational advantages over previous approaches. In the case of the temperature-density equation this development extends previous results by enlarging the class of expandable functions and has the added advantage of rigor and simplicity. As a natural extension of the Kinetic Theory results, an integral equation for the surface density is derived for half-space problems involving the boundary condition of arbitrary accommodation. / Ph. D.