Robustness of Maximin Space-filling Designs

In this report, we first have a review of the maximin space-filling design methods that is often applied and discussed in the literature (for example, Müller (2007)). Then we will discuss the robustness of the maximin space-filling design against model misspecification via numerical simulation. For this purpose, we will generate spatial data sets on a n x n grid and design points are selected from the n2 locations. The predictions at the unsampled locations are made based on the observations at these design points. Then the mean of the squared prediction errors are estimated as a measure of the robustness of the designs against possible model misspecification. Surprisingly, according to the simulation results, we find that the maximin space-filling designs may be robust against possible model misspecification in the sense that the mean of the squared prediction error does not increase significantly when the model is misspecified. Although the results were obtained based on simple models, this result is very inspiring. It will guide further numerical and theoretical studies which will be done as future work

The welfare effects of regulatory change on the Western Canadian grain handling and transportation system

Abstract Lisitza, Lyndon D. M.Sc. University of Saskatchewan, Saskatoon, May 2012. The Welfare Effects of Regulatory Change on the Western Canadian Grain Handling and Transportation System. Supervisor: Dr. Murray E. Fulton In 1996, the federal government took a significant step toward redefining the regulatory framework for grain transportation on the Prairies with the passing of the Canadian Transportation Act (CTA). The CTA contained two significant aspects that were to have a major impact on the GHTS. The first aspect concerned rail line abandonment. Under the CTA, protections afforded to the discontinuance of grain dependent branchlines were removed. Instead, railways were simply required to generate a three-year plan to indicate whether they intended to continue operating a branchline or whether they intended to sell, lease or abandon it. The second aspect was the introduction of regulated maximum freight rates, which removed the federal government from direct financial intervention in the GHTS. This policy was designed to replace the remnants of the long-standing Crow rate for Canadian railways. In order to determine if regulatory change has led to an overall improvement in GHTS welfare, and to determine if farmers have benefitted from regulatory change, this thesis examined the regulatory changes that have occurred since the passing of the Canada Transportation Act (Act). To provide some context for this analysis, this thesis presents a historical overview of the legislation and regulations leading up to the passing of the Act and provided a historical and current description of the GHTS market structure. Following the regulatory and industry overview, this thesis develops a theoretical framework capable of determining whether regulatory change has lead to an overall improvement in GHTS welfare and, if so, which industry participants have benefitted from this change. To help contextualize many of the concepts used in the theoretical framework, this thesis examines theories on the origin of regulation and looked specifically at two forms of thought: public interest theory and capture theory. As well, this thesis examines several ‘rate of return’ regulatory options available to the regulator, and provides an illustration of the ‘rate of return’ regulation of the WGTA in order to provide a regulatory baseline against which the 1996 CTA regulatory changes can be assessed. The intent of this thesis is to quantify the changes in consumer and producer surplus associated with regulatory change. Specifically, this examines the welfare changes in grain and non-grain markets that can be attributed to the shift from the WGTA to revenue cap regulation, increased railway capacity, a reduction in railway marginal cost and the removal of grain dependent branch lines (GDBLs). When considering the welfare effects solely attributed to the regulatory shift, the results indicate that the move from the WGTA to the revenue cap decreases the consumer surplus of farmers. Farmers experience an overall reduction in consumer surplus, largely due to the fact that the price farmers’ pay for grain transportation has risen and because the level of output they receive is less than that received under the WGTA. As a result of the regulatory shift, shippers in the non-grain market see an overall gain in consumer surplus. This increase is principally due to a shift in capacity allocation from the grain to the non-grain market as the railways respond to the higher marginal revenues they are able to earn in the non-grain market as opposed to the revenue cap regulated grain market. As such, shippers in the non-grain market are made better off. Although the railways experience a loss in producer surplus due to the regulatory shift, this loss is more than offset by the increase in producer surplus that the railways earn through a reduction in marginal costs. As such, the railways see an overall gain in producer surplus. As well, the federal government also experiences a gain in overall surplus. These gains are the result of the elimination of the subsidy that was paid to the railways under the WGTA as well as the removal of the additional dead weight loss that is incurred by society resulting from raising the taxes required to pay the subsidy. As such, the government (i.e., taxpayers) are better off as a result of the regulatory change

Low-field thermal mixing in [1-13C] pyruvic acid for brute-force hyperpolarization

We detail the process of low-field thermal mixing (LFTM) between 1H and 13C nuclei in neat [1-13C] pyruvic acid at cryogenic temperatures (4–15 K). Using fast-field-cycling NMR, 1H nuclei in the molecule were polarized at modest high field (2 T) and then equilibrated with 13C nuclei by fast cycling (∼300–400 ms) to a low field (0–300 G) that activates thermal mixing. The 13C NMR spectrum was recorded after fast cycling back to 2 T. The 13C signal derives from 1H polarization via LFTM, in which the polarized (‘cold’) proton bath contacts the unpolarised (‘hot’) 13C bath at a field so low that Zeeman and dipolar interactions are similar-sized and fluctuations in the latter drive 1H–13C equilibration. By varying mixing time (tmix) and field (Bmix), we determined field-dependent rates of polarization transfer (1/τ) and decay (1/T1m) during mixing. This defines conditions for effective mixing, as utilized in ‘brute-force’ hyperpolarization of low-γ nuclei like 13C using Boltzmann polarization from nearby protons. For neat pyruvic acid, near-optimum mixing occurs for tmix ∼ 100–300 ms and Bmix ∼ 30–60 G. Three forms of frozen neat pyruvic acid were tested: two glassy samples, (one well-deoxygenated, the other O2-exposed) and one sample pre-treated by annealing (also well-deoxygenated). Both annealing and the presence of O2 are known to dramatically alter high-field longitudinal relaxation (T1) of 1H and 13C (up to 102–103-fold effects). Here, we found smaller, but still critical factors of ∼(2–5)× on both τ and T1m. Annealed, well-deoxygenated samples exhibit the longest time constants, e.g., τ ∼ 30–70 ms and T1m ∼ 1–20 s, each growing vs. Bmix. Mixing ‘turns off’ for Bmix > ∼100 G. That T1m ≫ τ is consistent with earlier success with polarization transfer from 1H to 13C by LFTM

Combining biomarker and bulk compositional gradient analysis to assess reservoir connectivity

Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Organic Geochemistry 41 (2010): 812-821, doi:10.1016/j.orggeochem.2010.05.003.Hydraulic connectivity of petroleum reservoirs represents one of the biggest uncertainties for both oil production and petroleum system studies. Here, a geochemical analysis involving bulk and detailed measures of crude oil composition is shown to constrain connectivity more tightly than is possible with conventional methods. Three crude oils collected from different depths in a single well exhibit large gradients in viscosity, density, and asphaltene content. Crude oil samples are collected with a wireline sampling tool providing samples from well‐defined locations and relatively free of contamination by drilling fluids; the known provenance of these samples minimizes uncertainties in the subsequent analysis. The detailed chemical composition of almost the entire crude oil is determined by use of comprehensive two‐dimensional gas chromatography (GC×GC) to interrogate the nonpolar fraction and negative ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT‐ICR MS) to interrogate the polar fraction. The simultaneous presence of 25‐ norhopanes and mildly altered normal and isoprenoid alkanes is detected, suggesting that the reservoir has experienced multiple charges and contains a mixture of oils biodegraded to different extents. The gradient in asphaltene concentration is explained by an equilibrium model considering only gravitational segregation of asphaltene nanoaggregates; this grading can be responsible for the observed variation in viscosity. Combining these analyses yields a consistent picture of a connected reservoir in which the observed viscosity variation originates from gravitational segregation of asphaltene nanoaggregates in a crude oil with high asphaltene concentration resulting from multiple charges, including one charge that suffered severe biodegradation. Observation of these gradients having appropriate magnitudes suggests good reservoir connectivity with greater confidence than is possible with traditional techniques alone.The mass spectrometry work was supported by the NSF Division of Materials Research through DMR‐06‐54118, and the State of Florida

Inequities in access to mental health care at intersections of race/ethnicity, gender identity, and gender modality: An application of Multilevel Analysis of Individual Heterogeneity and Discriminatory Accuracy (MAIHDA)

Thesis (Master's)--University of Washington, 2024Transgender populations, and particularly transgender women of color, are burdened by high rates of both mental illness and healthcare avoidance. Despite this, research examining the patterns of non-use of mental healthcare within this community is lacking, and has further suffered due to the difficulty of collecting large, population-based samples of transgender adults in general, and transgender people of color in particular. We therefore use data from the Census Bureau’s new Household Pulse Study in conjunction with the novel Multilevel Analysis of Individual Heterogeneity and Discriminatory Accuracy (MAIHDA) method to assess the prevalence of unmet mental healthcare needs at critical intersections of gender modality, gender identity, and race/ethnicity. Participants were 699,843 U.S. adults who completed the Household Pulse Survey between July 2021 to May 2022. Participants were sorted into intersectional strata by race and ethnicity (Asian, Black, White, Hispanic, and mixed/another race), gender modality and sexuality (cisgender heterosexual, cisgender LGB+, and transgender) and gender identity (dichotomized here as masculine vs feminine). We then fit a multilevel log-binomial regression model with strata and participant-level random intercepts to assess the main effects, and calculated stratum-level residuals as a measure of intersectional effects. Unmet mental health needs were more prevalent among transgender people (PR=2.63, 95% CI= 2.22, 3.11), cisgender LGB+ people (PR=2.25, 95% CI=1.93, 2.63), women (PR=1.36, 95% CI= 1.25, 1.48), and people who self-identified as Black (PR=1.56, 95% CI=1.31, 1.86), Hispanic (PR=1.81, 95% CI=1.51, 2.15) mixed/another race (PR=2.11, 95% CI=1.75, 2.53). The most negative intersectional effects were for transfeminine people and for non-Black cisgender heterosexual men. The largest positive intersectional effects were for Black cisgender women and for transmasculine people. These findings suggest that although racism, transphobia, and misogyny might each independently increase the prevalence of unmet mental health needs, race and gender modality additionally impact the degree to which various groups are impacted by gender norms when seeking mental healthcare. Intersectional effects are thus essential to evaluate when studying mental healthcare use and non-use among transgender people of color

Collagen Structure and Its Modifications at Different Diseases

&lt;p&gt;The collagen superfamily of proteins plays a dominant role in maintaining the integrity of various tissues and also has a number of other important functions. The superfamily includes more than 20 collagen types with altogether. Most collagens form polymeric assemblies. such as fibrils, networks and filaments, and the superfamily can be divided into several families based on these assemblies and structural features. The critical roles of collagens have been clearly illustrated by the wide spectrum of diseases caused by the mutations that occur in genes coding different collagen types. Collagens are also major components of the extracellular matrix (ECM). The abnormal expression, proteolysis and structure of these collagens influence cellular functions to elicit multiple effects on tumors, including proliferation, initiation, invasion, metastasis, and therapy response.&lt;/p&gt;</jats:p

Hazing in K-12 Education: Academic Poster Reflection

This poster presentation describes the presence of hazing behaviors in the K-12 school environment, its prevalence, the impact on students and strategies to address it. Various authors suggest zero-tolerance policies such as an approach to confront hazing practices, however, such policies in schools have been eliminated by multiple states, including Illinois. The arguments in favor and against zero-tolerance policies are outlined. This project seeks to encapsulate current hazing concerns in K-12 education and provide recommendations to consider in future interventions and research.Ope