Parameter Estimation of a Cardiac Model Using the Local Ensemble Transform Kalman Filter

Cardiac arrhythmias are irregularities in the electrical activity in the heart; the electrical impulses in the heart become chaotic or disorganized, which can cause a possibly lethal problem to the contraction of the heart. In order to understand the dynamics of arrhythmias and to be able to predict and treat them, numerical models have been developed to capture the dynamics of the electrical impulses in the heart. In a clinical setting, optical mapping technologies — using cameras and voltage-sensitive dyes to capture the electrical impulses propagating across the heart — have been used to capture the dynamics of the electrical activity along the surface of the heart with high spatial and temporal resolution. Despite the high resolution provided by the optical mapping technologies along the surface of the heart, the techniques are unable to capture measurements of the voltage in the interior of the heart. Kalman Filters attempt to solve this problem by combining experimental data — that which is obtained by direct measurement, such as by optical mapping methods — with a mathematical model. This has been shown using synthetic data to be an effective method of reconstructing the dynamics of certain cardiac arrhythmias in tissue. It is desirable to be able to obtain the values of the parameters that guide the dynamical behavior of the cardiac arrhythmias in a given mathematical model. Knowledge of the values of the model parameters can be used to retroactively explain why dynamical effects occurred or to predict future behavior of the electrical impulses propagating throughout the cardiac tissue. In this thesis, we utilize a state-augmentation method of estimating model parameters using a nonlinear extension of the general Kalman Filter. We use a three-variable model of the cardiac action potential in conjunction with the Local Ensemble Transform Kalman Filter (LETKF) in order to estimate the state of the electrical impulses traveling along cardiac tissue. We show the viability of the state-augmentation methods of parameter estimation with the LETKF and determine three criteria that can be used to explain the effectiveness of the parameter estimation algorithm. We first establish the results by estimating a single parameter, and then expand our results by showing the same criteria hold when estimating multiple model parameters simultaneously. The results provide evidence that this method of parameter estimation is useful for cardiac models — both by a good estimation of the state and the predictable estimation of the model parameters — and suggest additional avenues of research for the preliminary work presented in this thesis

Quantitative sum rule analysis of low-temperature spectral functions

We analyze QCD and Weinberg-type sum rules in a low-temperature pion gas using vector and axial-vector spectral functions following from the model-independent chiral-mixing scheme. Toward this end we employ recently constructed vacuum spectral functions with ground and first-excited states in both channels and a universal perturbative continuum; they quantitatively describe hadronic tau-decay data and satisfy vacuum sum rules. These features facilitate the implementation of chiral mixing without further assumptions, and lead to in-medium spectral functions which exhibit a mutual tendency of compensating resonance and dip structures, suggestive for an approach toward structureless distributions. In the sum rule analysis, we account for pion mass corrections, which turn out to be significant. While the Weinberg sum rules remain satisfied even at high temperatures, the numerical evaluation of the QCD sum rules for vector and axial-vector channels reveals significant deviations setting in for temperatures beyond ~140 MeV, suggestive of additional physics beyond low-energy chiral pion dynamics.Comment: 8 pages, 3 figure

Cambrian-Ordovician Aquifer Sustainability Study Linn and Johnson County Groundwater Protected Area Linn and Johnson County, Iowa

The Linn and Johnson County Groundwater Protected Area site (LJCPA) is located in east-central Iowa. Eight water users with nine water use permits are found within the LJCPA that allow withdrawal from the Cambrian-Ordovician (CO) aquifer. Water use permits within the LJCPA include the City of Marion, City of North Liberty, City of Tiffin, City of Coralville, City of Iowa City, Archer Daniels Midland-Cedar Rapids (ADM), IngredionCedar Rapids, the University of Iowa - Oakdale Campus, and the University of Iowa - Water Treatment Plant (UI WTP). The LJCPA is one of two designated groundwater protected areas for the CO aquifer in Iowa.https://ir.uiowa.edu/igs_wrir/1020/thumbnail.jp

The Often‑Circuitous Path to Affirming Mental Health Care for Transgender and Gender‑Diverse Adults

Purpose of Review We describe recent research regarding access to affirming mental health services for transgender and gender-diverse (TGD) adults and explore new resources available for therapists to inform evidence-based practice with TGD clients. Recent Findings Barriers and facilitators at all socioecological levels impact TGD adults’ mental health help-seeking. TGD adults often interface with mental health providers while accessing gender-affirming medical care, though new standards of care are likely to alter this typically common path to mental health services. Efforts to improve therapist education, such as therapy manuals, are increasingly available and a necessary step to increase the number of competent, affirming therapists. Summary More work—both advocacy and research—is needed to fully expand accessible, affirming mental health services for TGD adults. Better understanding factors impacting different steps of the mental health help-seeking process and conducting randomized controlled trials of affirming mental health services are important next steps

First impressions online: The inclusion of transgender and gender nonconforming identities and services in mental healthcare providers’ online materials in the USA

Background: When accessing mental healthcare services, transgender and gender nonconforming (TGNC) individuals face systemic barriers to gender-affirmative care. Initial points of contact, like intake forms, may show limited consideration for the heterogeneity of TGNC identities and can lead to negative consequences prior to face-to-face interaction with providers. Aims: The first aim was to mimic a likely pathway a TGNC individual may follow to seek mental healthcare services in the USA and to describe the extent to which they may encounter enacted stigma or affirmative messages that may impede or facilitate access to care. The second aim was to determine if a positive State legal climate for TGNC people was associated with more affirmative provider materials. Methods: Content analysis was used to examine a national sample of websites and intake forms of mental healthcare providers who advertise online as working with TGNC clients. Intake forms were coded for usage of affirmative language in gender/sex questions and including questions for a client’s pronouns and preferred name. Websites were coded for mentioning a variety of services or resources for TGNC clients. Results: While provider websites were found through Google searches for a “gender therapist,” only 56.6% of websites stated a provider specialty to work with TGNC clients and 32.1% of websites had no mention of services or resources for TGNC people. Additionally, a significantly larger proportion of intake forms from States with legal protections for TGNC people used affirmative language in gender/sex questions and asked for a client’s pronouns than intake forms from States without legal protections. Discussion: Barriers to affirmative healthcare for TGNC people within patient and provider interactions have been identified in previous research and these data show TGNC individuals may face enacted stigma even in their search for a provider, particularly those TGNC people living in States without legal protections

Investigation of a Recharge Basin to Improve Drought Resiliency and Aquifer Sustainability Rock Valley Rural Water

https://ir.uiowa.edu/igs_wrir/1017/thumbnail.jp

Aquifer Sustainability at the Osceola County Rural Water System H-Series Wellfield

https://ir.uiowa.edu/igs_wrir/1019/thumbnail.jp

Sum Rules and Photon Emission in Hadronic Matter

In this work, we examine properties of quantum chromodynamics (QCD) at moderate temperatures and density. These conditions are reached in the later stages of ultra-relativistic heavy-ion collisions after the matter has cooled sufficiently to re-hadronize from a quark-gluon plasma. The properties of matter in this stage are expected to change smoothly with temperature. We explore this behavior in two ways. First, we use finite-temperature sum rules to analyze the properties of vector and axial-vector spectral functions at low temperatures. Previous models used in sum rule analyses frequently led to ambiguous applications. Here we avoid such ambiguities by using an improved vacuum spectral function model together with a strict leading-order-in-temperature expansion. This results in well-defined finite temperature spectral functions. Additionally, we incorporate a finite pion mass, which we show induces an analytical violation of the sum rules. We then proceed to numerically measure that violation. Second, we calculate thermal photon emissivities of QCD matter from interactions involving both mesons and baryons. We identify a novel source of thermal photons from a system composed of π, ρ, and ῳ mesons, then calculate photon emission rates from this system using both relativistic kinetic theory and thermal field theory. These rates are compared to existing calculations and found to be significant. We then calculate thermal photon emission rates from baryon interactions, using an exhaustive set of both strange and non-strange particles. We again find novel sources of photons from this system, compare the total rates to calculations of current state-of-the-art photon emission rates, and find them to be comparable

A Systematic Review of Recommendations for Behavioral Health Services for Transgender and Gender Diverse Adults: The Three-Legged Stool of Evidence-Based Practice is Unbalanced

There is a growing literature of clinical recommendations for transgender and gender diverse (TGD) affirming behavioral health care, yet it is unknown to what extent these recommendations are rooted in evidence-based practice (EBP). This systematic review included 65 articles published between 2009 and 2018 with recommendations for behavioral health services with TGD adults, emphasizing general clinical care. Coded variables included type of article, participant demographics, aspects of EBP, and whether care was informed by objective assessment. Most articles did not equally draw from all components of EBP. Recommendations for specific clinical problems are increasingly available and address diversity within TGD communities. More research, including clinical trials adapting established interventions, is needed to inform state-of-the-art TGD-affirmative behavioral health care