We prove that for every tree $T$ of radius $h$, there is an integer $c$ such that every $T$-minor-free graph is contained in $H\boxtimes K_c$ for some graph $H$ with pathwidth at most $2h-1$. This is a qualitative strengthening of the Excluded Tree Minor Theorem of Robertson and Seymour (GM I). We show that radius is the right parameter to consider in this setting, and $2h-1$ is the best possible bound.

Archaeological investigations at Bucklers Park in Crowthorne have revealed a window onto a significant later prehistoric place, which was used and revisited over 1700 years between the Early Bronze Age and later Iron Age (c. 1800–100 bc). Activity on site was based around the heating of water using fire-heated flint, producing three mounds of fire-cracked flint and burnt organic material. These ‘burnt mounds’ are known across later prehistoric Britain and Ireland, but the ways they may have been formed are uncertain, and they are arguably under-discussed in southern Britain. Whilst water was initially drawn from a stream, a series of wells were established at the site between the Middle Bronze Age and Early Iron Age, one of which contained a well-preserved log ladder. These wells were revisited and recut over long periods of time and during the Middle Iron Age the site’s function shifted dramatically when a roundhouse was constructed. The long-term use of the site, its excellent organic preservation, dating, and its location in a remote area on the Bagshot Heath, make it significant. This paper summarises the findings from the excavations, discussing the formation of the site in the context of wider research on later prehistoric burnt mounds.

Mercer (2018) makes a compelling argument for the urgent need to further research teacher psychology, focussing on language teachers. While there has been considerable research on language learner psychology and with considerable focus on individual differences (IDs), there have been comparatively few studies into language teacher psychology. Mercer (2018, p. 506) highlights that teachers are among the most important stake holders in the language learning and teaching process. Therefore, it is essential to understand the psychology of both learners and teachers to achieve the best learning outcomes.

In recent years, a variety of efforts have been made in political science to enable, encourage, or require scholars to be more open and explicit about the bases of their empirical claims and, in turn, make those claims more readily evaluable by others. While qualitative scholars have long taken an interest in making their research open, reflexive, and systematic, the recent push for overarching transparency norms and requirements has provoked serious concern within qualitative research communities and raised fundamental questions about the meaning, value, costs, and intellectual relevance of transparency for qualitative inquiry. In this Perspectives Reflection, we crystallize the central findings of a three-year deliberative process—the Qualitative Transparency Deliberations (QTD)—involving hundreds of political scientists in a broad discussion of these issues. Following an overview of the process and the key insights that emerged, we present summaries of the QTD Working Groups’ final reports. Drawing on a series of public, online conversations that unfolded at www.qualtd.net, the reports unpack transparency’s promise, practicalities, risks, and limitations in relation to different qualitative methodologies, forms of evidence, and research contexts. Taken as a whole, these reports—the full versions of which can be found in the Supplementary Materials—offer practical guidance to scholars designing and implementing qualitative research, and to editors, reviewers, and funders seeking to develop criteria of evaluation that are appropriate—as understood by relevant research communities—to the forms of inquiry being assessed. We dedicate this Reflection to the memory of our coauthor and QTD working group leader Kendra Koivu.1

Background: Vancomycin-resistant Enterococcus (VRE) is a leading cause of nosocomial infections that carries an increased risk of mortality when compared to vancomycin-sensitive Enterococcus (VSE). Data on the frequency of conversion between VSE and VRE in patients are scarce. Among patients presenting with VSE infections, little is known about the subsequent risk of conversion to VRE in the initial treatment period. Methods: A descriptive analysis of VSE to VRE conversion and a retrospective case-control study were performed examining cases of VSE that had subsequent cultures positive for VRE within 90 days within a quaternary healthcare system. Cases were obtained from June 2013 through December 2018. Controls were patients who had VSE culture followed by another VSE culture and were matched by organism (E. faecalis or E. faecium), time between cultures, and initial culture site. Age, gender, healthcare, antibiotic, Clostridiodes difficile, proton pump inhibitor (PPI) exposure, and H2 blocker exposures, and prior VRE infection or colonization were abstracted from the electronic medical record. A univariate analysis with the Fisher exact test was performed with significance considered for P < .05. Results: In total, 8,913 cases of E. faecalis and 2,322 cases of E. faecium were included in the study. Of 8,913 cases of E. faecalis, 51 of 8,503 (0.6%) cultured VRE after VSE, and 47 of 403 (11.7%) cultured VSE after initial VRE. Of E. faecium, 51 of 783 (6.5%) cultured VRE after VSE, and 76 of 1,532 (5.0%) cultured VSE after initial VRE. In total, 76 cases were matched with 99 controls. Patients converting from VSE to VRE were more likely to have prior admission to an intensive care unit (P = .0207), prior positive swab or culture for VRE (P = .0114), previous C. difficile infection (P = .0155), prior vancomycin (P = .0022) and cefepime (P = .0089) exposure. Patients receiving vancomycin after initial VSE culture were more likely to have subsequent cultures positive for VRE (P = .0053). There was no difference in age (P = .966) or male sex (P = .7588). Conclusions: Conversion from VSE to VRE is common, and E. faecium is more likely to become resistant than E. faecalis. Reversion to a vancomycin-sensitive phenotype is also common, and E. faecalis is more likely to show subsequent sensitivity than E. faecium. Previous admission to an intensive care unit, prior colonization or infection with VRE, prior C. difficile infection, and exposure to vancomycin and cefepime are risk factors for emergence of VRE after treatment for vancomycin-sensitive Enterococcus.

Funding: None

Disclosures: None

Background: Proper care and maintenance of central lines is essential to prevent central-line–associated bloodstream infections (CLABSI). Our facility implemented a hospital-wide central-line maintenance bundle based on CLABSI prevention guidelines. The objective of this study was to determine whether maintenance bundle adherence was influenced by nursing shift or the day of week. Methods: A central-line maintenance bundle was implemented in April 2018 at a 1,266-bed academic medical center. The maintenance bundle components included alcohol-impregnated disinfection caps on all ports and infusion tubing, infusion tubing dated, dressings, not damp or soiled, no oozing at insertion site greater than the size of a quarter, dressings occlusive with all edges intact, transparent dressing change recorded within 7 days, and no gauze dressings in place for >48 hours. To monitor bundle compliance, 4 non–unit-based nurse observers were trained to audit central lines. Observations were collected between August 2018 and October 2019. Observations were performed during all shifts and 7 days per week. Just-in-time feedback was provided for noncompliant central lines. Nursing shifts were defined as day (7:00 a.m. to 3:00 p.m.), evening (3:00 p.m. to 11:00 p.m.), and night (11:00 p.m. to 7:00 a.m.). Central-line bundle compliance between shifts were compared using multinomial logistic regression. Bundle compliance between week day and weekend were compared using Mantel-Haenszel 2 analysis. Results: Of the 25,902 observations collected, 11,135 (42.9%) were day-shift observations, 11,559 (44.6%) occurred on evening shift, and 3,208 (12.4%) occurred on the night shift. Overall, 22,114 (85.9%) observations occurred on a week day versus 3,788 (14.6%) on a Saturday or Sunday (median observations per day of the week, 2,570; range, 1,680–6,800). In total, 4,599 CLs (17.8%) were noncompliant with >1 bundle component. The most common reasons for noncompliance were dressing not dated (n = 1,577; 44.0%) and dressings not occlusive with all edges intact (n = 1340; 37.4%). The noncompliant rates for central-line observations by shift were 12.8% (1,430 of 1,1,135) on day shift, 20.4% (2,361 of 11,559) on evening shift, and 25.2% (808 of 3,208) on night shift. Compared to day shift, evening shift (OR, 1.74; 95% CI, 1.62–1.87; P < .001) and night shift (OR, 2.29; 95% CI, 2.07–2.52; P < .001) were more likely to have a noncompliant central lines. Compared to a weekday, observations on weekend days were more likely to find a noncompliant central line: 914 of 3,788 (24.4%) weekend days versus 3,685 of 22,114 (16.7%) week days (P < .001). Conclusions: Noncompliance with central-line maintenance bundle was more likely on evening and night shifts and during the weekends.

Funding: None

Disclosures: None

Little is known about the experiences of people living alone with dementia in the community and their non-resident relatives and friends who support them. In this paper, we explore their respective attitudes and approaches to the future, particularly regarding the future care and living arrangements of those living with dementia. The study is based on a qualitative secondary analysis of interviews with 24 people living alone with early-stage dementia in North Wales, United Kingdom, and one of their relatives or friends who supported them. All but four of the dyads were interviewed twice over 12 months (a total of 88 interviews). In the analysis, it was observed that several people with dementia expressed the desire to continue living at home for ‘as long as possible’. A framework approach was used to investigate this theme in more depth, drawing on concepts from the existing studies of people living with dementia and across disciplines. Similarities and differences in the future outlook and temporal orientation of the participants were identified. The results support previous research suggesting that the future outlook of people living with early-stage dementia can be interpreted in part as a response to their situation and a way of coping with the threats that it is perceived to present, and not just an impaired view of time. Priorities for future research are highlighted in the discussion.

The sodic amphiboles possess two independent chemical substitution series (Fe3+-Al and Fe2+-Mg) that combine to provide a ‘plane’ of compositions. Yet at no single T and P are compositions covering the whole plane stable: (i) pure riebeckite exists under low-P conditions but breaks down in normal blueschists to give deerite; (ii) ferro-glaucophane is in competition at all except the lowest blueschist temperatures with almandine garnet; (iii) magnesio-riebeckite is stable at high-T and low-P but within the blueschist facies is replaced by the alternative higher density aegirine-talc assemblage; and (iv) glaucophane is stable only at high-P.

At higher T and P than those of the blueschists, competition from NaCa pyroxenes, garnets, and deerite first erodes, and then removes, nearly all sodic amphibole compositions. At low-P the normal sodic amphibole-forming reactions from stilpnomelane and chlorite (in the presence of iron oxides, albite, etc.) produce an initial ‘rie-beckitic’ amphibole that subsequently becomes more glaucophanitic with increasing P. Under certain conditions, perhaps connected with hydrous fluid overpressures, these reactions become transposed such that crossitic compositions become replaced whilst ferroglaucophane to glancophane compositions remain stable.

The mineral howieite has a stability range that extends down to pressures at, or even below, those normally considered to represent blueschist facies metamorphism. Its structure, lying somewhere between a chain and a sheet silicate, can accommodate almost complete iron for manganese substitution as well as the more extraordinary ferrous iron for ferric iron substitution, that is tolerated by changes in the hydroxyl and water content of the unit cell. The ideal formula is NaM12 Si12(O,OH)44, where M is principally manganese and iron but may include limited amounts of aluminium and magnesium. Four new localities for howieite have been discovered by the author and the howieites from the eight localities that have been analysed here help complete the compositional spectrum. The most curious crystallographic feature of howieite is that although the structure seems capable of considerable chemical variation, it is only those howieites of approximate NaMn3Fe8(AlMg)1Si12(O,OH)44 composition that are well crystallized, often growing to over 10 mm in length.

Zussmanite has been found at only one locality: the Laytonville Quarry, Mendocino County, California. There are, however, present at this locality, two separate, but apparently inter-related minerals that from the evidence of chemistry, and limited diffraction information, appear to be zussmanite-type species. Their relative structural similarities are demonstrated within two rocks from the quarry in which a manganese concentration gradient has allowed ferrous-iron-rich zussmanites to develop partly contiguous overgrowths of one or other of these two minerals, one of which is a new form that has a provisionally determined ideal formula of KAlMn3−5-8Si17O42(OH)14 and that is separated from ideal zussmanite compositions (of the form Si17O42(OH)14) by an immiscibility gap. The other ‘zussmanite-type’ mineral has a composition that closely resembles a manganese-rich form of minne-sotaite.

The first zussmanite-type species (ZU2) has been separated and not unambiguous diffraction information obtained of its cell dimensions and powder lines, which are similar to those of zussmanite but appear to have an 8 % smaller cell-base and only a two-layer repeat (as in some of the zussmanite polytypes, and as in the talc structure). It is therefore considered possible that ZU2 has an altered compatibility between the tetrahedral and octa-hedral sheet overlap, perhaps from 13 (as in zussmanite) to 12. Whilst zussmanite appears to be a blueschist-eclogite mineral, ZU2 occurs under conditions at the low-pressure side of the blueschist facies.

An intermediate between zussmanite and the manganoan ‘minnesotaite’ is found in one rock in which the rims of zussmanite have been leached of potassium. As minnesotaite is more of a range of compositions than a structure (there is mounting evidence that it is not a simple talc-analogue) a consideration of the Laytonville manganoan minnesotaite as a zussmanite mineral is not unreasonable.

The Laytonville Quarry exotic block contains a series of deep-ocean sediments of varying Fe: Mn, Fe:Al and Fe2+ : Fe3+ contents, but all enriched in Fe-Mn carbonates. These sediments have a complex metamorphic history that has involved the early development of aegirine and garnet, followed by various phases of ‘secondary’ mineral growth, all of which required the addition of water to the metamorphic assemblages under high-P, low-T conditions. During the course of an early hydration episode deerite formed within most of the ironstones, and zussmanite in certain Fe-rich, Mn-poor pelites. At a later, and apparently lower pressure period in the metamorphic history, howieite, riebeckite, stilpnomelane, and a more manganous variety of zussmanite (ZU2) have overtaken much of the earlier mineralogy. Subsequent to this, and contemporaneous with the development of the tremolite-talc exotic block rind assemblage, there is a minor development of minnesotaite and ekmanite. During the course of the metamorphism the ironstones have become enriched in K and Na, necessary to form the blueschist meta-ironstone mineralogy. Such rocks therefore have the potential to reveal details of fluid expulsion within the subduction zone.

Good education requires student experiences that deliver lessons about practice as well as theory and that encourage students to work for the public good—especially in the operation of democratic institutions (Dewey 1923; Dewy 1938). We report on an evaluation of the pedagogical value of a research project involving 23 colleges and universities across the country. Faculty trained and supervised students who observed polling places in the 2016 General Election. Our findings indicate that this was a valuable learning experience in both the short and long terms. Students found their experiences to be valuable and reported learning generally and specifically related to course material. Postelection, they also felt more knowledgeable about election science topics, voting behavior, and research methods. Students reported interest in participating in similar research in the future, would recommend other students to do so, and expressed interest in more learning and research about the topics central to their experience. Our results suggest that participants appreciated the importance of elections and their study. Collectively, the participating students are engaged and efficacious—essential qualities of citizens in a democracy.