Properties of the Toric Rings of a Chordal Bipartite Family of Graphs

This project concerns the classification and study of a group of Koszul algebras coming from the toric ideals of a chordal bipartite infinite family of graphs (alternately, these rings may be interpreted as coming from determinants of certain ladder-like structures). We determine a linear system of parameters for each ring and explicitly determine the Hilbert series for the resulting Artinian reduction. As corollaries, we obtain the multiplicity and regularity of the original rings. This work extends results known for a subfamily coming from a two-sided ladder and includes constructive proofs which may be useful in future study of these rings and others. We also develop explicit elements in the Priddy complex which correspond via known isomorphisms to Tate variables in the acyclic closure of the residue field over the localization of our rings at their homogeneous maximal ideals

A 3D Parallel Algorithm for QR Decomposition

Interprocessor communication often dominates the runtime of large matrix computations. We present a parallel algorithm for computing QR decompositions whose bandwidth cost (communication volume) can be decreased at the cost of increasing its latency cost (number of messages). By varying a parameter to navigate the bandwidth/latency tradeoff, we can tune this algorithm for machines with different communication costs

Evaluating the Equality of Regression Coefficients for Multiple Group Comparisons: A Case of English Learner Subgroups by Home Languages

As the theme of the 2022 annual meeting of the American Education Research Association, cultivating equitable education systems has gained renewed attention amid an increasingly diverse society. However, systemic inequalities persist for traditionally underserved student populations. As a way to better address diverse students’ needs, it is of critical importance to understand different subgroups’ performances. In the educational measurement field, evaluating the differences among multiple groups is an important consideration in addressing fairness issues for diverse groups of students. This article offers one technique to do so. It demonstrates how commonly-used multiple regression analysis can be applied to evaluate the equivalence of predictive structure across multiple groups in place of the factor analytic approach that requires a relatively large sample size per subgroup and strong assumptions. The technique is utilized in examining the relationship between English language proficiency and academic performance of English learners in one state when the subgroups are categorized by home language. The results showed statistically significant group differences between the reference group (Spanish-speaking ELs) and other focal groups (different home-language ELs) in various levels of comparisons (model fit, model structure, and individual predictor weights). The strengths and limitations of a proposed multiple group regression (MGR) approach are discussed in the educational research context

Evaluation of cumulative cognitive deficits from electroconvulsive therapy

Background Electroconvulsive therapy (ECT) is the most effective acute treatment for severe depression, but widely held concerns about memory problems may limit its use. Aims To find out whether repeated or maintenance courses of ECT cause cumulative cognitive deterioration. Method Analysis of the results of 10 years of cognitive performance data collection from patients who have received ECT. The 199 patients had a total of 498 assessments, undertaken after a mean of 15.3 ECT sessions (range 0–186). A linear mixed-effect regression model was used, testing whether an increasing number of ECT sessions leads to deterioration in performance. Results The total number of previous ECT sessions had no effect on cognitive performance. The major factors affecting performance were age, followed by the severity of depression at the time of testing and the number of days since the last ECT session. Conclusions Repeated courses of ECT do not lead to cumulative cognitive deficits. This message is reassuring for patients, carers and prescribers who are concerned about memory problems and confusion during ECT. Electroconvulsive therapy (ECT) is the most effective acute treatment for severe depression,1 with reported remission rates above 50%.2,3 Although some reports demonstrate even higher remission rates (such as 75% in patients with psychotic depression4), these could be below 50% for treatment-resistant depression or in community settings.5,6 ECT is often portrayed in mainstream media as a barbaric treatment7 and its cognitive side-effects as profound and debilitating, leading to public, patient and carer concerns. ECT does cause retrograde amnesia and acute disorientation immediately following a treatment,8 however, research has suggested that this is only a short-lived side-effect. A meta-analysis by Semkovska & McLoughlin9 analysed the cognitive tests of 2981 patients from 84 studies, performed before and after single courses of ECT, and found that a decline in cognitive performance was limited to the first 3 days following a treatment. Patients showed no cognitive deterioration when tested 2 or more weeks after their last ECT session. This does not apply to retrograde amnesia, which was not part of this analysis, and it cannot be extended to cognitive functions that were not tested. Much less is known about the side-effects of long-term ECT, including maintenance ECT. A major concern of patients and some health professionals is that it could lead to progressive cognitive deficits, especially if given for prolonged periods of time. Small studies and case reports have addressed this question and have found no evidence to support this concern (see Discussion). Over the past 10 years we performed prospective cognitive tests on 199 patients, of whom 96 had >12 ECTsessions during their lifetime (the usual maximum duration of a single ECT course). We wanted to find out whether there was evidence that their cognitive performance deteriorated with the increasing number of ECT sessions

Readmissions and the quality of care in patients hospitalized with heart failure

Objectives. Clinical practice guidelines based on the results of randomized clinical trials recommend that patients with heart failure due to left ventricular systolic dysfunction (LVSD) be treated with angiotensin-converting enzyme inhibitors (ACEI) at doses shown to reduce mortality and readmission. This study examined the relationship between ACEI use at discharge and readmission among patients with heart failure due to LVSD. Methods and results. Data were abstracted from the medical records of 2943 randomly selected patients hospitalized for heart failure in 50 hospitals. The outcome of interest was the number of readmissions occurring up to 21 months after discharge. Six-hundred and eleven patients were eligible for analysis. Compared with patients discharged at a recommended ACEI dose, patients not prescribed an ACEI at discharge had an adjusted rate ratio of readmission (RR) of 1.74 [95% confidence interval (CI) 1.22-2.48], while patients prescribed an ACEI at less than a recommended dose had an RR of 1.24 (95% CI 0.91-1.69) (P = 0.005 for the trend). Conclusion. Our results show that ACEI use at discharge in patients with LVSD is associated with decreased rate of readmission. These findings suggest that compliance with the ACEI prescribing recommendations listed in clinical practice guidelines for patients with heart failure due to LVSD confers benefi

Double Burden of Malnutrition Workshop Facilitation Manual: Iquitos, Peru

This is a facilitation manual for workshops in Lima, Peru as part of the project “Addressing the double burden of malnutrition in Peru: using a community-based system dynamics approach to improve food systems”. The project is a collaboration between investigators at the Center of Excellence in Chronic Diseases (CRONICAS) at the University of Peruana Cayetano Heredia, Universidad de los Andes in Bogota, Peru, the Social System Design Lab at Washington University in St. Louis, USA and Imperial College London funded by the Biotechnology and Biological Science Research Council (Grant Ref: BB/T009004/1). It is a supplemental document associated with the paper “Mapping food system drivers of the double burden of malnutrition using community-based system dynamics: a case study in Peru by Carmen Quinteros-Reyes, Paraskevi Seferidi, Laura Guzman-Abello, Christopher Millett, Antonio Bernabé-Ortiz, Ellis Ballard

Double Burden of Malnutrition Workshop Facilitation Manual: Lima, Peru

This is a facilitation manual for workshops in Lima, Peru as part of the project “Addressing the double burden of malnutrition in Peru: using a community-based system dynamics approach to improve food systems”. The project is a collaboration between investigators at the Center of Excellence in Chronic Diseases (CRONICAS) at the University of Peruana Cayetano Heredia, Universidad de los Andes in Bogota, Peru, the Social System Design Lab at Washington University in St. Louis, USA and Imperial College London funded by the Biotechnology and Biological Science Research Council (Grant Ref: BB/T009004/1). It is a supplemental document associated with the paper “Mapping food system drivers of the double burden of malnutrition using community-based system dynamics: a case study in Peru by Carmen Quinteros-Reyes, Paraskevi Seferidi, Laura Guzman-Abello, Christopher Millett, Antonio Bernabé-Ortiz, Ellis Ballard

Student attitudes toward accentedness of native and nonnative speaking English teachers

The goal for this study was to examine participants’ familiarity with specific accents, whether participants were able to identify if a speaker was a native speaker (NS) or a non-native speaker (NNS), and what accent the speaker had. I also examined how the participants rated speakers on four Likert-scales of comprehensibility, intelligibility, accentedness, and acceptability as a teacher (the four dependent variables). I included 38 NS and 94 NNS participants from a range of first-language backgrounds. The participants listened to three NSs (Midwestern U.S., Southern U.S., and British) and two NNSs (Chinese and Albanian) and completed the identification and Likert-scale tasks outlined above. Results showed that NNSs were significantly less able than NSs to identify a speaker’s nativeness and accent. Results revealed that familiarity with an accent correlated with comprehensibility and acceptability as a teacher. For familiar accents, familiarity was a significant predictor of the participant ratings on the four dependent variables, though the predicted changes in ratings were small. Overall, participants had generally positive attitudes toward NNSETs; in relation to acceptability as a teacher, accent was the least influential of the dependent variables. I conclude by arguing that students should be exposed to a range of different accents, as familiarity with an accent facilitates comprehension. These findings also challenge current language center hiring practices that exclude NNSETs from jobs based on a non-native status; this study supports the notion that administrators should hire English language teachers based on professional credentials, and not based on accent