Wilson loop approach to fragile topology of split elementary band representations and topological crystalline insulators with time reversal symmetry

We present a general methodology towards the systematic characterization of crystalline topological insulating phases with time reversal symmetry (TRS).~In particular, taking the two-dimensional spinful hexagonal lattice as a proof of principle we study windings of Wilson loop spectra over cuts in the Brillouin zone that are dictated by the underlying lattice symmetries.~Our approach finds a prominent use in elucidating and quantifying the recently proposed ``topological quantum chemistry" (TQC) concept.~Namely, we prove that the split of an elementary band representation (EBR) by a band gap must lead to a topological phase.~For this we first show that in addition to the Fu-Kane-Mele $\mathbb{Z}_2$ classification, there is $C_2\mathcal{T}$-symmetry protected $\mathbb{Z}$ classification of two-band subspaces that is obstructed by the other crystalline symmetries, i.e.~forbidding the trivial phase. This accounts for all nontrivial Wilson loop windings of split EBRs \textit{that are independent of the parameterization of the flow of Wilson loops}.~Then, we show that while Wilson loop winding of split EBRs can unwind when embedded in higher-dimensional band space, two-band subspaces that remain separated by a band gap from the other bands conserve their Wilson loop winding, hence revealing that split EBRs are at least "stably trivial", i.e. necessarily non-trivial in the non-stable (few-band) limit but possibly trivial in the stable (many-band) limit.~This clarifies the nature of \textit{fragile} topology that has appeared very recently.~We then argue that in the many-band limit the stable Wilson loop winding is only determined by the Fu-Kane-Mele $\mathbb{Z}_2$ invariant implying that further stable topological phases must belong to the class of higher-order topological insulators.Comment: 27 pages, 13 figures, v2: minor corrections, new references included, v3: metastable topology of split EBRs emphasized, v4: prepared for publicatio

A Mixed-Methods Investigation of Factors and Scenarios Influencing College Students’ Decision to Complete Surveys at Five Mid-Western Universities

Achieving respectable response rates to surveys on university campuses has become increasingly more difficult, which can increase non-response error and jeopardize the integrity of data. Prior research has focused on investigating the effect of a single or small set of factors on college students’ decision to complete surveys. We used a concurrent mixed-method design to examine (1) college students’ rationales for choosing to complete or not complete a survey presented to them and (2) their perceptions on the importance of multiple factors on their decision to complete or not complete surveys in a higher education setting. A total of 837 undergraduate and graduate students across five institutions in the state of Ohio completed the qualitative survey component, 808 completed the 72-scenario close-ended survey component, and 701 completed the rank- order component. The survey was administered in the classroom either at the beginning or end of the class period. The college students reported that the person administering, topic, incentives, length, and method of administration are the factors most influencing their decision to complete a survey. The undergraduate students were significantly more likely than graduate students to include incentives as one of the top three important factors in deciding to complete a survey. Qualitative results additionally revealed that the students felt day/time and location of survey request plays an important role in their decision. Recommendations are provided to survey administrators regarding potential effective and ineffective survey recruitment strategies

Comprehensive Determination of Protein Tyrosine pK(a) Values for Photoactive Yellow Protein Using Indirect C-13 NMR Spectroscopy

Upon blue-light irradiation, the bacterium Halorhodospira halophila is able to modulate the activity of its flagellar motor and thereby evade potentially harmful UV radiation. The 14 kDa soluble cytosolic photoactive yellow protein (PYP) is believed to be the primary mediator of this photophobic response, and yields a UV/Vis absorption spectrum that closely matches the bacterium's motility spectrum. In the electronic ground state, the para-coumaric acid (pCA) chromophore of PYP is negatively charged and forms two short hydrogen bonds to the side chains of Glu-46 and Tyr-42. The resulting acid triad is central to the marked pH dependence of the optical-absorption relaxation kinetics of PYP. Here, we describe an NMR approach to sequence-specifically follow all tyrosine side-chain protonation states in PYP from pH 3.41 to 11.24. The indirect observation of the nonprotonated (13)C(γ) resonances in sensitive and well-resolved two-dimensional (13)C-(1)H spectra proved to be pivotal in this effort, as observation of other ring-system resonances was hampered by spectral congestion and line-broadening due to ring flips. We observe three classes of tyrosine residues in PYP that exhibit very different pK(a) values depending on whether the phenolic side chain is solvent-exposed, buried, or hydrogen-bonded. In particular, our data show that Tyr-42 remains fully protonated in the pH range of 3.41–11.24, and that pH-induced changes observed in the photocycle kinetics of PYP cannot be caused by changes in the charge state of Tyr-42. It is therefore very unlikely that the pCA chromophore undergoes changes in its electrostatic interactions in the electronic ground state

What value structure underlies shared decision making?:A qualitative synthesis of models of shared decision making

Objective: To construct the underlying value structure of shared decision making (SDM) models. Method: We included previously identified SDM models (n = 40) and 15 additional ones. Using a thematic analysis, we coded the data using Schwartz's value theory to define values in SDM and to investigate value relations. Results: We identified and defined eight values and developed three themes based on their relations: shared control, a safe and supportive environment, and decisions tailored to patients. We constructed a value structure based on the value relations and themes: the interplay of healthcare professionals' (HCPs) and patients’ skills [Achievement], support for a patient [Benevolence], and a good relationship between HCP and patient [Security] all facilitate patients’ autonomy [Self-Direction]. These values enable a more balanced relationship between HCP and patient and tailored decision making [Universalism]. Conclusion: SDM can be realized by an interplay of values. The values Benevolence and Security deserve more explicit attention, and may especially increase vulnerable patients’ Self-Direction. Practice implications: This value structure enables a comparison of values underlying SDM with those of specific populations, facilitating the incorporation of patients’ values into treatment decision making. It may also inform the development of SDM measures, interventions, education programs, and HCPs when practicing.</p

What value structure underlies shared decision making?:A qualitative synthesis of models of shared decision making

Objective: To construct the underlying value structure of shared decision making (SDM) models. Method: We included previously identified SDM models (n = 40) and 15 additional ones. Using a thematic analysis, we coded the data using Schwartz's value theory to define values in SDM and to investigate value relations. Results: We identified and defined eight values and developed three themes based on their relations: shared control, a safe and supportive environment, and decisions tailored to patients. We constructed a value structure based on the value relations and themes: the interplay of healthcare professionals' (HCPs) and patients’ skills [Achievement], support for a patient [Benevolence], and a good relationship between HCP and patient [Security] all facilitate patients’ autonomy [Self-Direction]. These values enable a more balanced relationship between HCP and patient and tailored decision making [Universalism]. Conclusion: SDM can be realized by an interplay of values. The values Benevolence and Security deserve more explicit attention, and may especially increase vulnerable patients’ Self-Direction. Practice implications: This value structure enables a comparison of values underlying SDM with those of specific populations, facilitating the incorporation of patients’ values into treatment decision making. It may also inform the development of SDM measures, interventions, education programs, and HCPs when practicing.</p

The Impact of Sustainable Investing: A Multidisciplinary Review

We conduct a multidisciplinary review of how sustainable investing impacts the environment and society. Our review starts from the insight that shareholders can create impact not only through (1) portfolio screening and (2) shareholder engagement (two impact strategies most used by mainstream shareholders) but also through (3) field building (an impact strategy most used by shareholders at the periphery of the financial sector). Based on this framework of three impact strategies, we integrate insights from four disciplines (management, finance, sociology, and ethics/sustainability) to reconstruct how each impact strategy influences corporate sustainability. We identify 15 impact mechanisms through which the impact strategies produce three types of impact: portfolio screening and shareholder engagement mostly create direct impact on companies, while field building creates indirect impact via other shareholders and indirect impact via the institutional context. Our review suggests that shareholder impact emerges gradually as different types of shareholders build on each other's efforts, which we use to outline a research agenda on shareholder impact as a distributed process

Tailor-to-Target: Configuring Collaborative Shareholder Engagements on Climate Change

We study collaborative shareholder engagements on climate change issues. These engagements involve coalitions of investors pursuing behind-the-scenes dialogue to encourage target firms to adopt environmental sustainability practices. Drawing on a unique dataset of 553 engagements coordinated by the United Nations-supported Principles for Responsible Investment (PRI)—and an innovative mixed-methods approach integrating fuzzy-set Qualitative Comparative Analysis (fsQCA) with regression analysis and qualitative interviews—we investigate how four coalition composition levers (coalition size, shareholding stake, experience, local access) combine to enable or hinder engagement success. We find that successful coalitions use four configurations of coalition composition levers that are tailored to target firms’ financial capacity and environmental predispositions—i.e., target firms’ receptivity. Unsuccessful configurations instead emphasize single levers at the expense of others. Drawing on qualitative interviews, we identify three mechanisms (synchronizing, contextualizing, overfocusing) that plausibly underly the identified configurations and provide investor coalitions with knowledge about target firms and their local contexts, thus enhancing communication and understanding between investor coalitions and target firms. Our study contributes an emerging “tailor-to-target” theory of collaborative shareholder engagement that extends the literature by showing the importance of designing investor coalitions for effective climate-related engagement; and the value of conceiving coalitions as different configurations of the same levers that can fit a target firm’s receptivity. From a practical perspective, our study prompts investors to move beyond one-size-fits-all approaches to instead tailor their engagement strategies to target firms’ receptivity

Paediatric Acute Respiratory Distress Syndrome Neuromuscular Blockade study (PAN-study):a phase IV randomised controlled trial of early neuromuscular blockade in moderate-to-severe paediatric acute respiratory distress syndrome

BACKGROUND: Paediatric acute respiratory distress syndrome (PARDS) is a manifestation of severe, life-threatening lung injury necessitating mechanical ventilation with mortality rates ranging up to 40–50%. Neuromuscular blockade agents (NMBAs) may be considered to prevent patient self-inflicted lung injury in PARDS patients, but two trials in adults with severe ARDS yielded conflicting results. To date, randomised controlled trials (RCT) examining the effectiveness and efficacy of NMBAs for PARDS are lacking. We hypothesise that using NMBAs for 48 h in paediatric patients younger than 5 years of age with early moderate-to-severe PARDS will lead to at least a 20% reduction in cumulative respiratory morbidity score 12 months after discharge from the paediatric intensive care unit (PICU). METHODS: This is a phase IV, multicentre, randomised, double-blind, placebo-controlled trial performed in level-3 PICUs in the Netherlands. Eligible for inclusion are children younger than 5 years of age requiring invasive mechanical ventilation with positive end-expiratory pressure (PEEP) ≥ 5 cm H(2)O for moderate-to-severe PARDS occurring within the first 96 h of PICU admission. Patients are randomised to continuous infusion of rocuronium bromide or placebo for 48 h. The primary endpoint is the cumulative respiratory morbidity score 12 months after PICU discharge, adjusted for confounding by age, gestational age, family history of asthma and/or allergy, season in which questionnaire was filled out, day-care and parental smoking. Secondary outcomes include respiratory mechanics, oxygenation and ventilation metrics, pulmonary and systemic inflammation markers, prevalence of critical illness polyneuropathy and myopathy and metrics for patient outcome including ventilator free days at day 28, length of PICU and hospital stay, and mortality DISCUSSION: This is the first paediatric trial evaluating the effects of muscular paralysis in moderate-to-severe PARDS. The proposed study addresses a huge research gap identified by the Paediatric Acute Lung Injury Consensus Collaborative by evaluating practical needs regarding the treatment of PARDS. Paediatric critical care practitioners are inclined to use interventions such as NMBAs in the most critically ill. This liberal use must be weighed against potential side effects. The proposed study will provide much needed scientific support in the decision-making to start NMBAs in moderate-to-severe PARDS. TRIAL REGISTRATION: ClinicalTrials.govNCT02902055. Registered on September 15, 2016