Rewritable Photonic Integrated Circuits Using Dielectric-assisted Phase-change Material Waveguides

Photonic integrated circuits (PICs) have the potential to drastically expand the capabilities of optical communications, sensing, and quantum information science and engineering. However, PICs are commonly fabricated using selective material etching, a subtractive process. Thus, the chip's functionality cannot be substantially altered once fabricated. Here, we propose to exploit wide-bandgap non-volatile phase-change materials (PCMs) to create a rewritable PIC platform. A PCM-based PIC can be written using a nano-second pulsed laser without removing any material, akin to rewritable compact disks. The whole circuit can then be erased by heating, and a completely new circuit can be rewritten. We designed a dielectric-assisted PCM waveguide consisting of a thick dielectric layer on top of a thin layer of wide-bandgap PCMs Sb2S3 and Sb2Se3. The low-loss PCMs and our engineered waveguiding structure lead to a negligible optical loss. Furthermore, we analyzed and specified the spatio-temporal laser pulse shape to write the PCMs. Our proposed platform will enable low-cost manufacturing and have a far-reaching impact on the rapid prototyping of PICs, validation of new designs, and photonic education

Improving access to social care services following acquired brain injury: a needs analysis

Context: Survivors of acquired brain injury (ABI) experience long-term cognitive, behavioural, psychological and social consequences often overlooked by health and social care providers, as are the implications for family members. Objective: To improve understanding of 1) the long-term community rehabilitation needs of ABI survivors and their families, and 2) their experiences of community health and social care provision within the United Kingdom. Method: A mixed-method, predominantly qualitative, approach was employed using questionnaires and semi-structured interviews in a two-stage design. Stage one: Seventy-six participants (31 ABI specialist professionals, 26 family members and 19 survivors) completed an online survey analysed using conventional content analysis. Participants were invited to take part in stage two, which recruited 21 participants (12 ABI survivors, 5 family members and 4 professionals) to semi-structured interviews analysed using a mixed thematic approach. Findings: Three main themes were identified with associated sub-themes 1) consequences of ABI ( cognitive and behavioural; psychological and social consequences, impact on family) 2) types of services required (tailored, specialist and interdisciplinary care) and 3) poor access to services (associated with; lack of understanding of ABI among professionals, the hidden nature of ABI, organisational structures and a lack of available services). Limitations: The study failed to achieve a sample distributed evenly across the United Kingdom, making it difficult to draw conclusions around best practice. Implications: The study concluded that professionals need training to understand the needs of ABI survivors and their families and that services need to be provided in a long-term, integrated manner

A Mixed-Method Multiple Case Study of Three Business Models for Local Healthy Food Delivery Systems in Underprivileged Urban Areas

Define a USDA food desert Analyze the three business models for benefits and deficiencies Identify methods for starting a sustainable mobile farmers market program. Over 40% of Berrien County Michigan land use is agricultural. Many products are fruits and vegetables. Yet, the county has six identified USDA defined Food Deserts. Past research, based on a mobile farmers market, confirmed local trends and deficits. The purpose for this research is to define a sustainable business model that delivers healthy local food options to USDA Food Deserts combating food inequity. A mixed method multiple case study was created to test three business models in one of the local Food Deserts. Results identify a sustainable model that provides local healthy food options. Model One developed lunchtime stops serving robust local businesses and community epicenters, with a goal of creating lunchtime profit, focusing evenings on service stops at a potential loss. Model Two required local farmers to provide produce at no cost to the market. Market locations were service stops embedded inside the residential community and stops increased to 15 per week. Model Three purchased local produce and focused stops on work and shopping locals, targeting the ALICE poverty segment. Models were tested for two weeks each with data collected for correlational comparison. Results show a high demand for lunch hour food options. Labor at such stops was increased over service stops. Model Two proved willingness from local farmers to support neighboring Food Deserts, yet sales didn’t equal market costs. Model Three demonstrated increased demand from ALICE segments. Conclusions indicate that sustainability could be reached with a hybrid model with limited volunteer intern positions. A three to five-year plan should be built with funding support ebbing with market growth

The bacterial microbiota regulates normal hematopoiesis via metabolite-induced type 1 interferon signaling

Antibiotic therapy, especially when administered long term, is associated with adverse hematologic effects such as cytopenia. Signals from the intestinal microbiota are critical to maintain normal hematopoiesis, and antibiotics can cause bone marrow suppression through depletion of the microbiota. We reported previously that STAT1 signaling is necessary for microbiota-dependent hematopoiesis, but the precise mechanisms by which the gut microbiota signals to the host bone marrow to regulate hematopoiesis remain undefined. We sought to identify the cell type(s) through which STAT1 promotes microbiota-mediated hematopoiesis and to elucidate which upstream signaling pathways trigger STAT1 signaling. Using conditional knockout and chimeric mice, we found that the microbiota induced STAT1 signaling in non-myeloid hematopoietic cells to support hematopoiesis and that STAT1 signaling was specifically dependent on type I interferons (IFNs). Indeed, basal type I IFN signaling was reduced in hematopoietic progenitor cells with antibiotic treatment. In addition, we discovered that oral administration of a commensal-derived product, NOD1 ligand, rescues the hematopoietic defects induced by antibiotics in mice. Using metabolomics, we identified additional microbially produced candidates that can stimulate type I IFN signaling to potentially rescue the hematopoietic defects induced by antibiotics, including phosphatidylcholine and γ-glutamylalanine. Overall, our studies define a signaling pathway through which microbiota promotes normal hematopoiesis and identify microbial metabolites that may serve as therapeutic agents to ameliorate antibiotic-induced bone marrow suppression and cytopenia

Projects in Geospatial Data Analysis: Spring 2015

This document contains semester projects for students in CSCI 4380/7000 Geospatial Data Analysis (GSA). The course explores the technical aspects of programmatic geospatial data analysis with a focus on GIS concepts, custom GIS programming, analytical and statistical methods, and open source tools and frameworks

Proportional-odds models for repeated composite and long ordinal outcome scales

In many medical studies, researchers widely use composite or long ordinal scores, that is, scores that have a large number of categories and a natural ordering often resulting from the sum of a number of short ordinal scores, to assess function or quality of life. Typically, we analyse these using unjustified assumptions of normality for the outcome measure, which are unlikely to be even approximately true. Scores of this type are better analysed using methods reserved for more conventional (short) ordinal scores, such as the proportional-odds model. We can avoid the need for a large number of cut-point parameters that define the divisions between the score categories for long ordinal scores in the proportional-odds model by the inclusion of orthogonal polynomial contrasts. We introduce the repeated measures proportional-odds logistic regression model and describe for long ordinal outcomes modifications to the generalized estimating equation methodology used for parameter estimation. We introduce data from a trial assessing two surgical interventions, briefly describe and re-analyse these using the new model and compare inferences from the new analysis with previously published results for the primary outcome measure (hip function at 12 months postoperatively). We use a simulation study to illustrate how this model also has more general application for conventional short ordinal scores, to select amongst competing models of varying complexity for the cut-point parameters

A prospective evaluation of thiamine and magnesium status in relation to clinicopathological characteristics and 1-year mortality in patients with Alcohol Withdrawal Syndrome

Background: Alcohol withdrawal syndrome (AWS) is routinely treated with B-vitamins. However, the relationship between thiamine status and outcome is rarely examined. The aim of the present study was to examine the relationship between thiamine and magnesium status in patients with AWS. Methods: Patients (n = 127) presenting to the Emergency Department with AWS were recruited to a prospective observational study. Blood samples were drawn to measure whole blood thiamine diphosphate (TDP) and serum magnesium concentrations. Routine biochemistry and haematology assays were also conducted. The Glasgow Modified Alcohol Withdrawal Score (GMAWS) measured severity of AWS. Seizure history and current medications were also recorded. Results: The majority of patients (99%) had whole blood TDP concentration within/above the reference interval (275–675 ng/gHb) and had been prescribed thiamine (70%). In contrast, the majority of patients (60%) had low serum magnesium concentrations (< 0.75 mmol/L) and had not been prescribed magnesium (93%). The majority of patients (66%) had plasma lactate concentrations above 2.0 mmol/L. At 1 year, 13 patients with AWS had died giving a mortality rate of 11%. Male gender (p < 0.05), BMI < 20 kg/m2 (p < 0.01), GMAWS max ≥ 4 (p < 0.05), elevated plasma lactate (p < 0.01), low albumin (p < 0.05) and elevated serum CRP (p < 0.05) were associated with greater 1-year mortality. Also, low serum magnesium at time of recruitment to study and low serum magnesium at next admission were associated with higher 1-year mortality rates, (84% and 100% respectively; both p < 0.05). Conclusion: The prevalence of low circulating thiamine concentrations were rare and it was regularly prescribed in patients with AWS. In contrast, low serum magnesium concentrations were common and not prescribed. Low serum magnesium was associated more severe AWS and increased 1-year mortality

Local Phenomena Shape Backyard Soil Metabolite Composition

Soil covers most of Earth’s continental surface and is fundamental to life-sustaining processes such as agriculture. Given its rich biodiversity, soil is also a major source for natural product drug discovery from soil microorganisms. However, the study of the soil small molecule profile has been challenging due to the complexity and heterogeneity of this matrix. In this study, we implemented high-resolution liquid chromatography–tandem mass spectrometry and large-scale data analysis tools such as molecular networking to characterize the relative contributions of city, state and regional processes on backyard soil metabolite composition, in 188 soil samples collected from 14 USA States, representing five USA climate regions. We observed that region, state and city of collection all influence the overall soil metabolite profile. However, many metabolites were only detected in unique sites, indicating that uniquely local phenomena also influence the backyard soil environment, with both human-derived and naturally-produced (plant-derived, microbially-derived) metabolites identified. Overall, these findings are helping to define the processes that shape the backyard soil metabolite composition, while also highlighting the need for expanded metabolomic studies of this complex environment.This research was supported by start-up funds from the University of Oklahoma (to L.-I.M.). Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye

Planetary Candidates Observed by Kepler V: Planet Sample from Q1-Q12 (36 Months)

The Kepler mission discovered 2842 exoplanet candidates with 2 years of data. We provide updates to the Kepler planet candidate sample based upon 3 years (Q1-Q12) of data. Through a series of tests to exclude false-positives, primarily caused by eclipsing binary stars and instrumental systematics, 855 additional planetary candidates have been discovered, bringing the total number known to 3697. We provide revised transit parameters and accompanying posterior distributions based on a Markov Chain Monte Carlo algorithm for the cumulative catalogue of Kepler Objects of Interest. There are now 130 candidates in the cumulative catalogue that receive less than twice the flux the Earth receives and more than 1100 have a radius less than 1.5 Rearth. There are now a dozen candidates meeting both criteria, roughly doubling the number of candidate Earth analogs. A majority of planetary candidates have a high probability of being bonafide planets, however, there are populations of likely false-positives. We discuss and suggest additional cuts that can be easily applied to the catalogue to produce a set of planetary candidates with good fidelity. The full catalogue is publicly available at the NASA Exoplanet Archive.Comment: Accepted for publication, ApJ

Roles of allostatic load, lifestyle and clinical risk factors in mediating the association between education and coronary heart disease risk in Europe

Background Previous studies have shown that differential exposure to lifestyle factors may mediate the association between education and coronary heart diseases (CHD). However, few studies have examined the potential roles of allostatic load (AL) or differential susceptibility. Methods 25 310 men and 26 018 women aged 35\u201374 and CHD free at baseline were identified from 21 European cohorts and followed for a median of 10 years, to investigate the mediating role of AL, as well as of smoking, alcohol use and body mass index (BMI), on educational differences in CHD incidence, applying marginal structural models and three-way decomposition. Results AL is a mediator of the association between educational status and CHD incidence, with the highest proportion mediated observed among women and largely attributable to differential exposure, (28% (95% CI 19% to 44%)), with 8% (95% CI 0% to 16%) attributable to differential susceptibility. The mediating effects of smoking, alcohol and BMI, compared with AL, were relatively small for both men and women. Conclusion Overall, the educational inequalities in CHD incidence were partially mediated through differential exposure to AL. By contrast, the mediation of the educational gradient in CHD by investigated lifestyle risk factors was limited. As differential susceptibility in men was found to have a predominant role in the accumulation of AL in low educational classes, the investigation of AL-related risk factors is warranted