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We study the back stable Schubert calculus of the infinite flag variety. Our main results are:
– a formula for back stable (double) Schubert classes expressing them in terms of a symmetric function part and a finite part;
– a novel definition of double and triple Stanley symmetric functions;
– a proof of the positivity of double Edelman–Greene coefficients generalizing the results of Edelman–Greene and Lascoux–Schützenberger;
– the definition of a new class of bumpless pipedreams, giving new formulae for double Schubert polynomials, back stable double Schubert polynomials, and a new form of the Edelman–Greene insertion algorithm;
– the construction of the Peterson subalgebra of the infinite nilHecke algebra, extending work of Peterson in the affine case;
– equivariant Pieri rules for the homology of the infinite Grassmannian;
– homology divided difference operators that create the equivariant homology Schubert classes of the infinite Grassmannian.
Food insecurity has been shown to be associated with fast-food consumption. However, to date, studies on this specific topic are scarce. Therefore, the aim of the present study was to investigate the association between food insecurity and fast-food consumption in adolescents aged 12-15 years from 68 countries (7 low-income, 27 lower middle-income, 20 upper middle-income, 14 high-income countries). Cross-sectional, school-based data from the Global School-based Student Health Survey were analyzed. Data on past 30-day food insecurity (hunger) and fast-food consumption in the past 7 days were collected. Multivariable logistic regression and meta-analysis were conducted to assess associations. Models were adjusted for age, sex, and body mass index. There were 180,164 adolescents aged 12-15 years [mean (SD) age 13.8 (1.0) years; 50.8% boys] included in the analysis. Overall, severe food insecurity (i.e., hungry because there was not enough food in home most of the time or always) was associated with 1.17 (95%CI=1.08-1.26) times higher odds for fast-food consumption. The estimates pooled by country-income levels were significant in low-income countries (adjusted odds ratio [aOR]=1.30; 95%CI=1.05-1.60), lower middle-income countries (aOR=1.15; 95%CI=1.02-1.29), and upper middle-income countries (aOR=1.26; 95%CI=1.07-1.49), but not in high-income countries (aOR=1.04; 95%CI=0.88-1.23). The mere co-occurrence of food insecurity and fast-food consumption is of public health importance. To tackle this issue, a strong governmental and societal approach is required to utilize effective methods as demonstrated in some high-income countries such as the implementation of food banks and the adoption of free school meals.
Short stature may reflect health in early life and be an enduring disability. How birth weight, gender, household, elementary schooling and diet play a role in associations between stature and overall school competence (OSC) have been assessed.
The 2001–2002 Nutrition and Health Survey in Taiwan (NAHSIT) for elementary schoolchildren (n 2274, 52·1 % boys) was linked to birth records. It provided sociodemographic, dietary quality, body compositional and school performance (as Scale for Assessing Emotional Disturbance, SAED; OSC as an SAED subscale) data. Lower birth weight was ≤15th percentile: 2850 g for boys and 2700 g for girls, and stature as z-scores for Taiwanese. Multivariable linear regression was used for relationships between OSC and stature. Trends in OSC by stature and school grade were assessed.
The 2001–2002 NAHSIT for elementary schoolchildren.
Totally, 2274 schoolchildren aged 6–13 years.
Compared to normal height (−2< height for age z-score (HAZ) <2), shorter girls (HAZ ≤ −2) had a lower OSC (8·87 v. 10·5, P < 0·05) and taller girls (HAZ ≥ 2) had a better OSC (12·3 v. 10·5, P < 0·001). Maternal education and household income each contributed more than 5 % of OSC variance. OSC and HAZ among girls were positively associated and emotional disturbance negatively associated. Shortness-associated lower OSC underwent remediation with advancing school grade. Stature and OSC were not evidently related in boys.
Shorter stature can compromise OSC among school girls. The major determinants in shorter girls are less household income and limited parental education.
This chapter reviews the quantitative corpus linguistic literature on development of cohesion in first- and second-language writing. It first provides a theoretical and methodological context for such work by discussing the two main frameworks within which cohesion has been researched. It then critically reviews an extensive body of literature to establish what substantive conclusions can be drawn and what might constitute productive foci for future research. Interest in cohesion as a correlate of development has been less intense than that seen for grammar, vocabulary, and formulaic language, and few consistent patterns have emerged. While there is some indication that a small number of measures are associated with development, evidence on these is too sparse for any confident conclusions to be drawn. Moreover, quantitative measures of cohesion appear to be highly contextually specific, depending crucially on the nature of the text and on the writer's estimation of their audience's topic knowledge.
This chapter reviews the quantitative corpus linguistic literature on formulaic language development in writing. It first provides a theoretical and methodological context by discussing the construct of formulaic language and the various ways in which it has been operationalised in studies of writing development. It then critically reviews the literature to establish what substantive conclusions can be drawn and what might constitute productive foci for future research. The review highlights a lack of interest in first-language studies. However, second-language studies have seen a rapid expansion of interest over the last decades, which has yielded a number of consistent patterns. In particular, writing quality is positively associated with the percentage of n-grams attested in a reference corpus, the mean strength of association between collocates (again as attested in a reference corpus), and the prevalence of sequences which analysts subjectively identify as formulaic. It is also negatively associated with use of formulas copied from source materials. Key areas in which further methodological development is needed include: understanding how analysts identify sequences as formulaic; increasing the size and rigour of studies looking at discourse functions of lexical bundles; understanding the impact of reference corpus on findings; developing corpora representative of learner input.
This chapter establishes a theoretical and methodological foundation for the quantitative corpus linguistic study of writing development. First, it defines and discusses the central constructs of writing, writing proficiency, development, and quantitative corpus linguistics. Second, it sets out four assumptions on which, we argue, quantitative corpus approaches rest and discusses in detail both the strengths of these approaches and the methodological challenges they need to confront. Third, it gives a detailed discussion of specific methodological issues related to defining and measuring key variables of development and context and of establishing the status of particular measures of language use. Finally, the chapter reviews one particular quantitative corpus linguistic approach (multidimensional analysis) which raises important questions about quantitative corpus linguistic methodology as a whole.
This chapter brings together discussions and evidence from the preceding chapters to draw conclusions about first- and second-language writing development and about quantitative corpus linguistics as a methodology. It first summarises the key patterns of development in terms of grammar, vocabulary, formulaic language, and cohesion. It then discusses implications of these findings for the key constructs of time- and quality-related development and draws methodological conclusions with regard to how quantitative measures of development have been, and in the future could be, theorised and operationalised and the types of text samples on which studies have been, and could be, built. The chapter ends by setting out a number of key priorities for future research, grouped under the headings of theorisation, broadening attention to contexts, and integration with other methods.
This chapter reviews the quantitative corpus linguistic literature on syntactic development in first- and second-language writing. It first provides a theoretical and methodological context for such work by discussing the construct of syntactic proficiency. It then critically reviews an extensive body of literature to establish what substantive conclusions can be drawn and how future research could most productively develop. The strongest developmental patterns are found for generic measures of syntactic complexity, as operationalised through measures such as mean length of sentence/T-unit/clause and subordinate clause ratios. However, we argue that such measures are relatively uninformative with regard to a detailed understanding of development. Our review of more specific syntactic measures highlights a number of key features which have the potential to give useful insights into language development, while also underscoring the fragmentary nature of the measures studied to date. Methodologically, the review identifies a pervasive lack of conceptual clarity regarding what is measured and why. We find important unacknowledged differences in how key terms (e.g. clause, noun phrase) are defined and operationalised, which make it difficult to build a theoretically meaningful and cohesive developmental picture.
This chapter reviews the quantitative corpus linguistic literature on vocabulary development in first- and second-language writing. It first provides a theoretical and methodological context for such work by discussing the construct of vocabulary proficiency. It then critically reviews an extensive body of literature to establish what substantive conclusions can be drawn and what might constitute productive foci for future research. The strongest developmental patterns are found for measures of vocabulary diversity and use of academic vocabulary. There are also important, but complex, developmental patterns with regard to use of high- versus low-frequency words. However, the current range of measures attested in the literature has significant limitations: they are limited in scope, focusing almost exclusively on breadth, rather than depth, of vocabulary knowledge; relationships between measures and knowledge constructs is often unclear; the relationships between measures themselves, which often overlap with each other in complex ways, are largely unexamined; measures are often too coarse-grained, and may consequently disguise important developmental patterns by conflating distinct constructs.
This chapter sets out the aims of the book and delimits its scope by defining the field of quantitative corpus linguistics (QCL), describing its key strengths as a way of understanding written-language development, and setting out some of the methodological problems which researchers need to untangle. It then outlines the systematic literature reviews on which the book is based and provides a broad overview of the trajectories this literature has taken over time.
Quantitative corpus research on written language development has expanded rapidly in recent years, assisted by the ever-increasing power and accessibility of software capable of reliably analysing huge collections of learner writing. For this work to reach its full potential, it is important that researchers have a strong understanding of its methodological foundations and of the existing empirical evidence base on which it can build. This book provides the most comprehensive discussion to date of research in this area. Covering both first and second language learning contexts, it sets out a coherent theoretical framework and systematically reviews studies published over the last seventy years in order to establish what such research has taught us about written language development, what it hasn't taught us, and what we should do next. Timely and original, this is an essential reference work for academic researchers and students of first and second language writing.
The COVID-19 pandemic has led to global shortages of N95 respirators. Reprocessing of used N95 respirators may provide a higher filtration crisis alternative, but it is unknown if effective sterilization can be achieved for a virus without impairing respirator function. We evaluated the viricidal efficacy of Bioquell vaporized hydrogen peroxide (VHP) on contaminated N95 respirators and tested the particulate particle penetration and inhalation/exhalation resistance of respirators after multiple cycles of VHP.
3M 1870 N95 respirators (3M, St. Paul, MN) were contaminated with 3 aerosolized bacteriophages: T1, T7, and Pseudomonas phage phi-6 followed by one cycle of VHP decontamination using a BQ-50 system (Bioquell, Horsham, PA). Additionally, new and unused respirators were sent to an independent laboratory, Nelson Labs (Salt Lake City, UT), for particulate filter penetration testing and inhalation/exhalation resistance after 3 and 5 cycles of VHP.
A single VHP cycle resulted in complete eradication of bacteriophage from respirators (limit of detection 10 PFU). Respirators showed acceptable limits for inhalation/exhalation resistance after 3 and 5 cycles of VHP. Respirators demonstrated a filtration efficiency >99 % after 3 cycles, but fell below 95% after 5 cycles of HPV.
Bioquell VHP demonstrated high viricidal activity for N95 respirators inoculated with aerosolized bacteriophages. Bioquell technology can be scaled for simultaneous decontamination of a large number of used but otherwise intact respirators. Reprocessing should be limited to 3 cycles due to concerns both about impact of clinical wear and tear on fit, and to decrement in filtration after 3 cycles.
This is the first report on the association between trauma exposure and depression from the Advancing Understanding of RecOvery afteR traumA(AURORA) multisite longitudinal study of adverse post-traumatic neuropsychiatric sequelae (APNS) among participants seeking emergency department (ED) treatment in the aftermath of a traumatic life experience.
We focus on participants presenting at EDs after a motor vehicle collision (MVC), which characterizes most AURORA participants, and examine associations of participant socio-demographics and MVC characteristics with 8-week depression as mediated through peritraumatic symptoms and 2-week depression.
Eight-week depression prevalence was relatively high (27.8%) and associated with several MVC characteristics (being passenger v. driver; injuries to other people). Peritraumatic distress was associated with 2-week but not 8-week depression. Most of these associations held when controlling for peritraumatic symptoms and, to a lesser degree, depressive symptoms at 2-weeks post-trauma.
These observations, coupled with substantial variation in the relative strength of the mediating pathways across predictors, raises the possibility of diverse and potentially complex underlying biological and psychological processes that remain to be elucidated in more in-depth analyses of the rich and evolving AURORA database to find new targets for intervention and new tools for risk-based stratification following trauma exposure.
Background: A penicillin allergy guidance document containing an algorithm for challenging penicillin allergic patients with β-lactams was developed by the antimicrobial stewardship program (ASP). As part of this algorithm, a “graded challenge” order set was created containing antimicrobial orders and safety medications along with monitoring instructions. The process is designed to challenge patients at low risk of reaction with infusions of 1% of the target dose, then 10%, and finally the full dose, each 30 minutes apart. We evaluated outcomes from the order set. Methods: Orders of the graded challenge over 17 months (March 2018 through July 2019) were reviewed retrospectively. Data were collected on ordering and outcomes of the challenges and allergy documentation. Use was evaluated based on ASP-recommended indications: history of IgE-mediated or unknown reaction plus (1) no previous β-lactam tolerance and the reaction occurred >10 years ago, or (2) previous β-lactam tolerance, now requiring a different β-lactam for treatment. Only administered challenges were included and descriptive statistics were utilized. Results: Of 67 orders, 57 graded challenges were administered to 56 patients. The most common allergies were penicillins (87.7%) and cephalosporins (38.6%), with the most common reactions being unknown (41.7%) or hives (22%). The most common antibiotics challenged were ceftriaxone (43.9%), cefepime (21.1%), and cefazolin (5.3%). Antibiotics given prior to challenge included vancomycin (48.2%), fluoroquinolones (35.7%), carbapenems (21.4%), aztreonam (19.6%), and clindamycin (12.5%). The median duration of challenged antibiotic was 6 days. The infectious diseases service was consulted on 59.6% of challenges and 75.4% of challenges were administered in non-ICU settings. There was 1 reaction (1.8%) involving a rash with the second infusion, which was treated with oral diphenhydramine and had no lasting effects. Based on indications, 80.7% of challenges were aligned with ASP guidance criteria. The most common use outside of these criteria was in patients without IgE-mediated reactions (10.5%). Most of these had minor rashes and could have received a full dose of a cephalosporin. Allergy information was updated in the electronic health record after 91.2% of challenges. Conclusions: We demonstrated the utility of a graded challenge process at our academic medical center. It was well tolerated, ordered frequently by noninfectious diseases clinicians, administered primarily in non-ICU settings, and regularly resulted in updated allergy information in the medical record. With many patients initially receiving broad-spectrum antibiotics with high costs or increased rates of adverse effects, graded challenges can potentially prevent the use of suboptimal therapies with minimal time and resource investment.
Disclosures: Scott Bergman reports a research grant from Merck.