Direct EIT Reconstructions of Complex Admittivities on a Chest-Shaped Domain in 2-D

Electrical impedance tomography (EIT) is a medical imaging technique in which current is applied on electrodes on the surface of the body, the resulting voltage is measured, and an inverse problem is solved to recover the conductivity and/or permittivity in the interior. Images are then formed from the reconstructed conductivity and permittivity distributions. In the 2-D geometry, EIT is clinically useful for chest imaging. In this work, an implementation of a D-bar method for complex admittivities on a general 2-D domain is presented. In particular, reconstructions are computed on a chest-shaped domain for several realistic phantoms including a simulated pneumothorax, hyperinflation, and pleural effusion. The method demonstrates robustness in the presence of noise. Reconstructions from trigonometric and pairwise current injection patterns are included

Computational tools for quadratic Chabauty

http://math.bu.edu/people/jbala/2020BalakrishnanMuellerNotes.pdfhttp://math.bu.edu/people/jbala/2020BalakrishnanMuellerNotes.pdfFirst author draf

The medicine hat block and the early paleoproterozoic assembly of Western Laurentia

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. The accretion of the Wyoming, Hearne, and Superior Provinces to form the Archean core of western Laurentia occurred rapidly in the Paleoproterozoic. Missing from Hoffman’s (1988) original rapid aggregation model was the Medicine Hat block (MHB). The MHB is a structurally distinct, complex block of Precambrian crystalline crust located between the Archean Wyoming Craton and the Archean Hearne Province and overlain by an extensive Phanerozoic cover. It is distinguished on the basis of geophysical evidence and limited geochemical data from crustal xenoliths and drill core. New U‐Pb ages and Lu‐Hf data from zircons reveal protolith crystallization ages from 2.50 to 3.28 Ga, magmatism/metamorphism at 1.76 to 1.81 Ga, and εHfT values from −23.3 to 8.5 in the Archean and Proterozoic rocks of the MHB. These data suggest that the MHB played a pivotal role in the complex assembly of western Laurentia in the Paleoproterozoic as a conjugate or extension to the Montana Metasedimentary Terrane (MMT) of the northwestern Wyoming Province. This MMT–MHB connection likely existed in the Mesoarchean, but it was broken sometime during the earliest Paleoproterozoic with the formation and closure of a small ocean basin. Closure of the ocean led to formation of the Little Belt arc along the southern margin of the MHB beginning at approximately 1.9 Ga. The MHB and MMT re‐joined at this time as they amalgamated into the supercontinent Laurentia during the Great Falls orogeny (1.7–1.9 Ga), which formed the Great Falls tectonic zone (GFTZ). The GFTZ developed in the same timeframe as the better‐known Trans‐Hudson orogen to the east that marks the merger of the Wyoming, Hearne, and Superior Provinces, which along with the MHB, formed the Archean core of western Laurentia

“Technically an abortion”: understanding perceptions and definitions of abortion in the United States

Anti-abortion legislation in the United States exploits misinformation and ignores medical definitions to curtail access to essential healthcare. Little is known about how individuals most likely to need this care define abortion, in general or as distinct from miscarriage, and how this might impact access to, utilization of, and experiences of care. Using mixed-method card sort and vignette data from cognitive interviews (n = 64) and a national online survey (n = 2009), we examined individuals’ understandings of pregnancy outcomes including abortion and miscarriage. Our findings show that people hold varying ideas of what constitutes an abortion. Many respondents considered ‘intent’ when classifying pregnancy outcomes and focused on intervention to distinguish between miscarriages and abortions. Particularly, medical intervention was found as a defining feature of abortion. Lack of knowledge regarding pregnancy experiences and ambiguity surrounding early stages of pregnancy also influenced respondents' understanding of abortion. We find that abortion and miscarriage definitions are socially constructed and multi-layered. Advancing our understanding of abortion and miscarriage definitions improves reproductive health research by elucidating potential areas of confusion that may lead to misreporting of reproductive experiences as well as highlighting ways that blurred definitions may be exploited by abortion opponents

Multi-system factors associated with metatarsophalangeal joint deformity in individuals with type 2 diabetes

The underlying factors contributing to metatarsophalangeal joint deformity, a known precursor to skin breakdown in individuals with diabetes mellitus (DM), is likely to involve multiple body systems. The purpose of this cross-sectional study was to identify multi-system factors associated with metatarsophalangeal joint deformity in individuals with type 2 DM and peripheral neuropathy

Pursuing High Performance in Rural Health Care

In 2001, the Institute of Medicine (IOM) called for transformation of the United States health care system to make it safe, effective, patient-centered, timely, efficient, and equitable.1 The journey toward these six aims in public policy and the private sector is underway, but fundamental challenges detailed by the IOM remain. Patients are injured at alarming rates, wide variation in care exists across geographies, patients complain of insensitive and/or inaccessible health care providers, health care costs are nearly twice that in other developed countries, and nearly 50 million Americans lack health insurance. As a result, our health care is often fragmented, uncoordinated, and excessively costly. In fact, the United States health care system has been called a “non-system.” The rural health care landscape is additionally challenged by independent and autonomous providers often struggling to survive financially, burdensome geographic separations in health care services, and incompatible information technologies. As a result, resources are wasted, patients are harmed, and rural communities are neglected. Despite persistent rural challenges, public policies during the past 30 years have helped build and stabilize rural health care services. New payments have increased revenue for physicians practicing in shortage areas, rural hospitals certified as Critical Access Hospitals (very small hospitals in isolated places), Sole Community Hospitals (larger hospitals also in isolated areas), and Rural Health Clinics (primary care clinics staffed by nurse practitioners and/or physician assistants). New programs continue to provide technical assistance and grants to rural hospitals (Medicare Rural Hospital Flexibility Program), fund installation of telemedicine equipment, and promote rural health professions education. These successes have required political capital and developmental resources to support a system that delivers discrete and uncoordinated health care services, provided by specific professionals and institutions, each paid on a per-service basis. Yet, progressive work by the Institute of Medicine (especially the Rural Health Committee document Quality Through Collaboration: The Future of Rural Health Care), the Commonwealth Commission on a High Performance Healthcare System, and other organizations suggest more effective strategies to improve and sustain the health of rural people..

Quadratic Chabauty for modular curves: algorithms and examples

We describe how the quadratic Chabauty method may be applied to determine the set of rational points on modular curves of genus g whose Jacobians have Mordell–Weil rank g. This extends our previous work on the split Cartan curve of level 13 and allows us to consider modular curves that may have few known rational points or nontrivial local height contributions away from our working prime. We illustrate our algorithms with a number of examples where we determine the set of rational points on several modular curves of genus 2 and 3: this includes Atkin–Lehner quotients X^+_0 (N) of prime level N, the curve X_S4 (13), as well as a few other curves relevant to Mazur’s Program B.https://arxiv.org/abs/2101.01862First author draf

Mapping the molecular surface of the analgesic NaV1.7-selective peptide Pn3a reveals residues essential for membrane and channel interactions

Compelling human genetic studies have identified the voltage-gated sodium channel NaV1.7 as a promising therapeutic target for the treatment of pain. The analgesic spider venom-derived peptide µtheraphotoxin-Pn3a is an exceptionally potent and selective inhibitor of NaV1.7, however, little is known about the structure-activity relationships or channel interactions that define this activity. We rationally designed seventeen Pn3a analogues and determined their activity at hNaV1.7 using patchclamp electrophysiology. The positively charged amino acids K22 and K24 were identified as crucial for Pn3a activity, with molecular modeling identifying interactions of these residues with the S3-S4 loop of domain II of hNaV1.7. Removal of hydrophobic residues Y4, Y27 and W30 led to a loss of potency (>250-fold), while replacement of negatively charged D1 and D8 residues with a positively charged lysine led to increased potencies (>13-fold), likely through alterations in membrane lipid interactions. Mutating D8 to an asparagine led to the greatest improvement in Pn3a potency at NaV1.7 (20-fold), whilst maintaining >100-fold selectivity over the major off-targets NaV1.4, NaV1.5 and NaV1.6. The Pn3a[D8N] mutant retained analgesic activity in vivo, significantly attenuating mechanical allodynia in a clinically relevant mouse model of post-surgical pain at doses 3-fold lower than wild-type Pn3a, without causing motor adverse effects. Results from this study will facilitate future rational design of potent and selective peptidic NaV1.7 inhibitors for the development of more efficacious and safer analgesics but also to further investigate the involvement of NaV1.7 in pain

Advancing the Transition to a High Performance Rural Health System

There are growing concerns about the current and future state of rural health. Despite decades of policy efforts to stabilize rural health systems through a range of policies and loan and grant programs, accelerating rural hospital closures combined with rapid changes in private and public payment strategies have created widespread concern that these solutions are inadequate for addressing current rural health challenges. The rural health system of today is the product of legacy policies and programs that often do not “fit” current local needs. Misaligned incentives undermine high-value and efficient care delivery. While there are limitations related to scalability in rural health system development, rural communities do have enormous potential to achieve the objectives of a high performance rural health system. This brief (and a companion paper at http://www.rupri.org/areas-of-work/health-policy/) discusses strategies and options for creating a pathway to a transformed, high performing rural health system

Pursuing High Performance in Rural Health Care

Rural Futures Lab Foundation Papers are intended to present current thinking on the economic drivers and opportunities that will shape the future of rural America. They provide the foundation upon which it will be possible to answer the question that drives the Lab’s work—What has to happen today in order to achieve positive rural outcomes tomorrow