Showing papers by "Boston College published in 2019"
TL;DR: In this article, an industry equilibrium model where firms have a choice to engage in corporate social responsibility (CSR) activities is presented, where CSR as an investment to increase product differen...
Abstract: This paper presents an industry equilibrium model where firms have a choice to engage in corporate social responsibility (CSR) activities. We model CSR as an investment to increase product differen...
564 citations
TL;DR: In this paper, the authors used scanning tunnelling microscopy to elucidate the atomically resolved electronic states and their magnetic response in the kagome magnet Co3Sn2S2.
Abstract: Electronic systems with flat bands are predicted to be a fertile ground for hosting emergent phenomena including unconventional magnetism and superconductivity1–15, but materials that manifest this feature are rare. Here, we use scanning tunnelling microscopy to elucidate the atomically resolved electronic states and their magnetic response in the kagome magnet Co3Sn2S2 (refs. 16–20). We observe a pronounced peak at the Fermi level, which we identify as arising from the kinetically frustrated kagome flat band. On increasing the magnetic field up to ±8 T, this state exhibits an anomalous magnetization-polarized many-body Zeeman shift, dominated by an orbital moment that is opposite to the field direction. Such negative magnetism is induced by spin–orbit-coupling quantum phase effects21–25 tied to non-trivial flat band systems. We image the flat band peak, resolve the associated negative magnetism and provide its connection to the Berry curvature field, showing that Co3Sn2S2 is a rare example of a kagome magnet where the low-energy physics can be dominated by the spin–orbit-coupled flat band. The authors show that a magnetic material with kagome lattice planes hosts a flat band near the Fermi level. Electrons in this band exhibit ‘negative magnetism’ due to the Berry curvature.
325 citations
TL;DR: In this article, the effects of two types of celebrities (Instagram celebrity vs traditional celebrity) on source trustworthiness, brand attitude, envy, and social presence were investigated in a randomized two-group comparison.
Abstract: The purpose of this paper is to test the effects of two types of celebrities (Instagram celebrity vs traditional celebrity) on source trustworthiness, brand attitude, envy and social presence. The proposed theoretical model consists of the celebrity type as the independent variable, social presence as the mediator and self-discrepancy as the moderator.,A randomized two-group comparison (Instagram celebrity vs traditional celebrity) between-subjects experiment (n=104) was conducted.,The results indicate that consumers exposed to Instagram celebrity’s brand posts perceive the source to be more trustworthy, show more positive attitude toward the endorsed brand, feel stronger social presence and feel more envious of the source than those consumers exposed to traditional celebrity’s brand posts. Structural equation modeling (Mplus 8.0) and bootstrap confidence intervals indicate that social presence mediates the causal effects of celebrity type on trustworthiness, brand attitude and envy. Multiple regression analyses reveal the moderating effects of appearance-related actual–ideal self-discrepancy.,Ultimately, managerial implications for social media marketing and Instagram influencer-based branding are provided. From the perspective of marketing planning, the findings speak to the power of influencer marketing as an effective branding strategy.,The paper discusses theoretical implications for the marketing literature on celebrity endorsements.
315 citations
Harvard University1, University of Antioquia2, Boston College3, Brigham and Women's Hospital4, University of Arizona5, Arizona State University6, Gordon College7, University of California, Santa Barbara8, Translational Genomics Research Institute9, University of Gothenburg10, Sahlgrenska University Hospital11, Boston University12, University of Southern California13, Children's Hospital Los Angeles14
TL;DR: A unique case from the Colombian cohort of autosomal dominant Alzheimer’s disease is reported in which disease progression is substantially delayed despite unusually high amyloid plaque pathology, possibly related to a rare mutation in APOE3.
Abstract: We identified a PSEN1 (presenilin 1) mutation carrier from the world's largest autosomal dominant Alzheimer's disease kindred, who did not develop mild cognitive impairment until her seventies, three decades after the expected age of clinical onset. The individual had two copies of the APOE3 Christchurch (R136S) mutation, unusually high brain amyloid levels and limited tau and neurodegenerative measurements. Our findings have implications for the role of APOE in the pathogenesis, treatment and prevention of Alzheimer's disease.
278 citations
TL;DR: A large bulk photovoltaic effect is observed in the type-I Weyl semimetal TaAs, and attributed to the diverging Berry curvature of the Weyl nodes.
Abstract: Broadband, efficient and fast conversion of light to electricity is crucial for sensing and clean energy. The bulk photovoltaic effect (BPVE) is a second-order nonlinear optical effect that intrinsically converts light into electrical current. Here, we demonstrate a large mid-infrared BPVE in microscopic devices of the Weyl semimetal TaAs. This discovery results from combining recent developments in Weyl semimetals, focused-ion beam fabrication and theoretical works suggesting a connection between BPVE and topology. We also present a detailed symmetry analysis that allows us to separate the shift current response from photothermal effects. The magnitude and wavelength range of the assigned shift current may impact optical detectors, clean energy and topology, and demonstrate the utility of Weyl semimetals for practical applications.
241 citations
TL;DR: Analysis of a natural history of song shows that music appears in every society observed; that variation in song events is well characterized by three dimensions; that musical behavior varies more within societies than across them on these dimensions; and that music is regularly associated with behavioral contexts such as infant care, healing, dance, and love.
Abstract: What is universal about music, and what varies? We built a corpus of ethnographic text on musical behavior from a representative sample of the world's societies, as well as a discography of audio recordings. The ethnographic corpus reveals that music (including songs with words) appears in every society observed; that music varies along three dimensions (formality, arousal, religiosity), more within societies than across them; and that music is associated with certain behavioral contexts such as infant care, healing, dance, and love. The discography-analyzed through machine summaries, amateur and expert listener ratings, and manual transcriptions-reveals that acoustic features of songs predict their primary behavioral context; that tonality is widespread, perhaps universal; that music varies in rhythmic and melodic complexity; and that elements of melodies and rhythms found worldwide follow power laws.
239 citations
TL;DR: A large and growing body of literature has contributed to our understanding of whether and why financial reporting affects investment decision-making as discussed by the authors, and a framework to organize this literature, and highlight opportunities for future research.
230 citations
TL;DR: This review aims to summarize efforts in this area, with a focus on materials-related considerations, and pays particular attention to strategies proposed to address the stability and catalytic issues, which are two key factors limiting the implementation of efficient photoelectrode materials.
Abstract: Photoelectrochemical (PEC) water splitting has been intensively studied in the past decades as a promising method for large-scale solar energy storage. Among the various issues that limit the progress of this field, the lack of photoelectrode materials with suitable properties in all aspects of light absorption, charge separation and transport, and charge transfer is a key challenge, which has attracted tremendous research attention. A large variety of compositions, in different forms, have been tested. This review aims to summarize efforts in this area, with a focus on materials-related considerations. Issues discussed by this review include synthesis, optoelectronic properties, charge behaviors and catalysis. In the recognition that thin-film materials are representative model systems for the study of these issues, we elected to focus on this form, so as to provide a concise and coherent account on the different strategies that have been proposed and tested. Because practical implementation is of paramount importance to the eventual realization of using solar fuel for solar energy storage, we pay particular attention to strategies proposed to address the stability and catalytic issues, which are two key factors limiting the implementation of efficient photoelectrode materials. To keep the overall discussion focused, all discussions were presented within the context of water splitting reactions. How the thin-film systems may be applied for fundamental studies of the water splitting chemical mechanisms and how to use the model system to test device engineering design strategies are discussed.
197 citations
TL;DR: In this paper, the authors present an improved hybrid sea-level reconstruction during 1900-2015 that combines previous techniques at time scales where they perform best, finding a persistent acceleration in GMSL since the 1960s and demonstrate that this is largely associated with sea-layer changes in the Indo-Pacific and South Atlantic.
Abstract: Previous studies reconstructed twentieth-century global mean sea level (GMSL) from sparse tide-gauge records to understand whether the recent high rates obtained from satellite altimetry are part of a longer-term acceleration. However, these analyses used techniques that can only accurately capture either the trend or the variability in GMSL, but not both. Here we present an improved hybrid sea-level reconstruction during 1900–2015 that combines previous techniques at time scales where they perform best. We find a persistent acceleration in GMSL since the 1960s and demonstrate that this is largely (~76%) associated with sea-level changes in the Indo-Pacific and South Atlantic. We show that the initiation of the acceleration in the 1960s is tightly linked to an intensification and a basin-scale equatorward shift of Southern Hemispheric westerlies, leading to increased ocean heat uptake, and hence greater rates of GMSL rise, through changes in the circulation of the Southern Ocean. Satellite altimetry shows global mean sea-level rise acceleration; however, sparse tide-gauge data limit understanding of the longer-term trend. A hybrid method of reconstruction for 1900–2015 shows acceleration since the 1960s, linked to increases and shifts in Southern Hemisphere westerly winds.
185 citations
TL;DR: Johnson describes ERV origins, their diversity and their relationships to retroviruses and discusses the potential for ERVs to reveal virus–host interactions on evolutionary timescales and describes some of the many examples of cellular functions, including protein-coding genes and regulatory elements, that have evolved from ERVs.
Abstract: Retroviruses infect a broad range of vertebrate hosts that includes amphibians, reptiles, fish, birds and mammals. In addition, a typical vertebrate genome contains thousands of loci composed of ancient retroviral sequences known as endogenous retroviruses (ERVs). ERVs are molecular remnants of ancient retroviruses and proof that the ongoing relationship between retroviruses and their vertebrate hosts began hundreds of millions of years ago. The long-term impact of retroviruses on vertebrate evolution is twofold: first, as with other viruses, retroviruses act as agents of selection, driving the evolution of host genes that block viral infection or that mitigate pathogenesis, and second, through the phenomenon of endogenization, retroviruses contribute an abundance of genetic novelty to host genomes, including unique protein-coding genes and cis-acting regulatory elements. This Review describes ERV origins, their diversity and their relationships to retroviruses and discusses the potential for ERVs to reveal virus-host interactions on evolutionary timescales. It also describes some of the many examples of cellular functions, including protein-coding genes and regulatory elements, that have evolved from ERVs.
185 citations
TL;DR: In this paper, the authors propose a rationale and research agenda for applied psychologists and career development professionals to contribute to the many challenges related to human rights and decent work, including a rise of unemployment, underemployment and precarious work across the globe.
Abstract: Building on new developments in the psychology of working framework (PWF) and psychology of working theory (PWT), this article proposes a rationale and research agenda for applied psychologists and career development professionals to contribute to the many challenges related to human rights and decent work. Recent and ongoing changes in the world are contributing to a significant loss of decent work, including a rise of unemployment, underemployment, and precarious work across the globe. By failing to satisfy human needs for economic survival, social connection, and self-determination, the loss of decent work undermines individual and societal well-being, particularly for marginalized groups and those without highly marketable skills. Informed by innovations in the PWF/PWT, we offer exemplary research agendas that focus on examining the psychological meaning and impact of economic and social protections, balancing caregiving work and market work, making work more just, and enhancing individual capacities ...
TL;DR: Pollution prevention presents a major, largely unexploited opportunity to improve children's health and prevent NCDs, especially in LMICs.
TL;DR: In this article, the authors examined publicly traded firms in China and found significantly lower tax avoidance by SOEs relative to non-SOEs, and link their results to managerial incentives through promotion tests, finding that higher SOE tax rates are associated with higher promotion frequencies of SOE managers.
TL;DR: In this article, an ideal triangular lattice of effective Jeff's = 1/2 moments with no inherent site disorder was investigated, and it was shown that an external magnetic field strongly perturbs the quantum disordered ground state and induces a clear transition into a collinear ordered state, consistent with a long predicted up-up-down structure for a triangular-lattice XXZ Hamiltonian driven by quantum fluctuations.
Abstract: Antiferromagnetically coupled S = 1/2 spins on an isotropic triangular lattice are the paradigm of frustrated quantum magnetism, but structurally ideal realizations are rare. Here, we investigate NaYbO2, which hosts an ideal triangular lattice of effective Jeff = 1/2 moments with no inherent site disorder. No signatures of conventional magnetic order appear down to 50 mK, strongly suggesting a quantum spin liquid ground state. We observe a two-peak specific heat and a nearly quadratic temperature dependence, in agreement with expectations for a two-dimensional Dirac spin liquid. Application of a magnetic field strongly perturbs the quantum disordered ground state and induces a clear transition into a collinear ordered state, consistent with a long-predicted up–up–down structure for a triangular-lattice XXZ Hamiltonian driven by quantum fluctuations. The observation of spin liquid signatures in zero field and quantum-induced ordering in intermediate fields in the same compound demonstrates an intrinsically quantum disordered ground state. We conclude that NaYbO2 is a model, versatile platform for exploring spin liquid physics with full tunability of field and temperature. At zero magnetic field, the triangular-lattice antiferromagnet NaYbO2 shows the absence of long-range magnetic order down to 50 mK, consistent with quantum spin liquid behaviour. An external field renders the system a collinear ordered phase.
TL;DR: In this article, the authors examined how competition among suppliers affects their willingness to provide trade credit financing and found that retailers with dispersed suppliers obtain less trade credit than those whose suppliers are more concentrated.
TL;DR: Recent advances in the understanding of the electric double layer are reviewed with a particular focus on the interfacial distribution of cations and the cations' hydration states in the vicinity of the electrode under various experimental conditions.
Abstract: Electrocatalysis is central to the production of renewable fuels and high-value commodity chemicals. The electrolyte and the electrode together determine the catalytic properties of the liquid/solid interface. In particular, the cations of the electrolyte can greatly change the rates and reaction selectivity of many electrocatalytic processes. For this reason, the careful choice of the cation is an essential step in the design of catalytic interfaces with high selectivity for desired high-value products. To make such a judicious choice, it is critical to understand where in the electric double layer the cations reside and the various distinct mechanistic impacts they can have on the electrocatalytic process of interest. In this perspective, we review recent advances in the understanding of the electric double layer with a particular focus on the interfacial distribution of cations and the cations' hydration states in the vicinity of the electrode under various experimental conditions. Furthermore, we summarize the different ways in which cations can alter the rates and selectivity of chemical processes at electrified interfaces and identify possible future areas of research in this field.
TL;DR: The observations show the unexpected role of an E3 ligase as a co-receptor that directly participates in receptor oligomerization and ligand discrimination, and highlights a previously unrecognized mechanism by which the innate immune system measures foreign nucleic acid length, a common criterion for self versus non-self nucleic acids discrimination.
TL;DR: A revision to the Middle-Range Theory of Self-Care of Chronic Illness where symptoms are clearly integrated with the self-care behaviors of self- care maintenance, monitoring, and management is proposed.
Abstract: The Middle-Range Theory of Self-Care of Chronic Illness has been used widely since it was first published in 2012. With the goal of theoretical refinement in mind, we evaluated the theory to identify areas where the theory lacked clarity and could be improved. The concept of self-care monitoring was determined to be underdeveloped. We do not yet know how the process of symptom monitoring influences the symptom appraisal process. Also, the manner in which self-care monitoring and self-care management are associated was thought to need refinement. As both of these issues relate to symptoms, we decided to enrich the Middle-Range Theory with knowledge from theories about symptoms. Here, we propose a revision to the Middle-Range Theory of Self-Care of Chronic Illness where symptoms are clearly integrated with the self-care behaviors of self-care maintenance, monitoring, and management.
TL;DR: The theoretical model, a layered ecological model of the Multicultural Guidelines, is presented along with 10 corresponding guidelines and is applicable to psychologists in their work with clients, students, research participants, and in practice, education, research, and/or consultation.
Abstract: The initial version of the Multicultural Guidelines, titled Guidelines on Multicultural Education, Training, Research, Practice, and Organizational Change for Psychologists, was published in 2002. Since then, there has been significant growth in research and theory regarding multicultural contexts. The revised Multicultural Guidelines are conceptualized to reconsider diversity and multicultural practice within professional psychology at this period in time, with intersectionality as its primary purview. Psychologists are encouraged to incorporate developmental and contextual antecedents of identity and consider how they can be acknowledged, addressed, and embraced to generate more effective models of professional engagement. The Multicultural Guidelines incorporate broad reference group identities that acknowledge within-group differences and the role of self-definition. Identity is shaped across contexts and time by cultural influences including age, generation, gender, gender identity, ethnicity, race, religion, spirituality, language, sexual orientation, social class, education, employment, ability status, national origin, immigration status, and historical as well as ongoing experiences of marginalization. The theoretical model, a layered ecological model of the Multicultural Guidelines, is presented along with 10 corresponding guidelines. The guidelines are applicable to psychologists in their work with clients, students, research participants, and in practice, education, research, and/or consultation. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
TL;DR: In this article, the authors contribute to customer experience management theory and practice in three important ways: off-line, on-line and offline, and in postpurchase consumption context.
Abstract: Contextualized in postpurchase consumption in business-to-business settings, the authors contribute to customer experience (CX) management theory and practice in three important ways. First, by off...
TL;DR: A set of stereochemically complex and structurally diverse compounds were created from the diterpene natural product pleuromutilin using the complexity-to-diversity strategy, identifying a compound that induces rapid ferroptotic death of cancer cells.
Abstract: The chemical diversification of natural products provides a robust and general method for the creation of stereochemically rich and structurally diverse small molecules. The resulting compounds have physicochemical traits different from those in most screening collections, and as such are an excellent source for biological discovery. Herein, we subject the diterpene natural product pleuromutilin to reaction sequences focused on creating ring system diversity in few synthetic steps. This effort resulted in a collection of compounds with previously unreported ring systems, providing a novel set of structurally diverse and highly complex compounds suitable for screening in a variety of different settings. Biological evaluation identified the novel compound ferroptocide, a small molecule that rapidly and robustly induces ferroptotic death of cancer cells. Target identification efforts and CRISPR knockout studies reveal that ferroptocide is an inhibitor of thioredoxin, a key component of the antioxidant system in the cell. Ferroptocide positively modulates the immune system in a murine model of breast cancer and will be a useful tool to study the utility of pro-ferroptotic agents for treatment of cancer. A set of stereochemically complex and structurally diverse compounds were created from the diterpene natural product pleuromutilin using the complexity-to-diversity strategy. Phenotypic screening identified a compound that induces rapid ferroptotic death of cancer cells. Experiments to probe the mechanism revealed the compound to be an inhibitor of thioredoxin.
TL;DR: This tutorial review describes recent developments in catalytic reaction design that involve catalyst-promoted 1,2-metalate shifts as a critical part of the reaction mechanism.
Abstract: This tutorial review describes recent developments in catalytic reaction design that involve catalyst-promoted 1,2-metalate shifts as a critical part of the reaction mechanism. Issues pertaining to catalysis, stereoselectivity, and reaction mechanism are discussed.
TL;DR: Jiang et al. as discussed by the authors study the introduction of a wealth management robo-adviser that constructs portfolios tailored to investors' holdings and preferences, and find that adopters exhibit declines in prominent behavioral biases, including the disposition, trend chasing, and rank effect.
Abstract: We study the introduction of a wealth-management robo-adviser that constructs portfolios tailored to investors’ holdings and preferences. Adopters are similar to non-adopters in terms of demographics and prior interactions with human advisers but tend to be more active and have greater assets under management. Investors adopting robo-advising experience diversification benefits. Ex ante undiversified investors increase stock holdings and hold portfolios with less volatility and better returns. Already well-diversified investors hold fewer stocks, yet see some reduction in volatility, and trade more after adoption. All investors increase attention based on online account logins. We find that adopters exhibit declines in prominent behavioral biases, including the disposition, trend chasing, and rank effect. Our results emphasize the promises and pitfalls of robo-advising tools, which are becoming ubiquitous all over the world.Received May 31, 2017; editorial decision August 21, 2018 by Editor Wei Jiang.
University of Wisconsin-Madison1, University of Geneva2, Northeastern University3, University of Illinois at Urbana–Champaign4, University of Minnesota5, University of Vienna6, University of Alabama at Birmingham7, University of Duisburg-Essen8, Temple University9, Ruhr University Bochum10, Leiden University11, University of South Florida12, University of Padua13, University of California, San Francisco14, Cognition and Brain Sciences Unit15, University of Lausanne16, University of Bergamo17, Radboud University Nijmegen18, University of California, Irvine19, Dresden University of Technology20, University of Koblenz and Landau21, University of British Columbia22, Karolinska Institutet23, University of California, Berkeley24, University of California, Santa Barbara25, North Carolina State University26, Arizona State University27, Rush University28, Hebrew University of Jerusalem29, Federal University of Rio de Janeiro30, Trinity College, Dublin31, Ohio State University32, University of Southern California33, Martin Luther University of Halle-Wittenberg34, University of California, Riverside35, University of Oxford36, Boston College37, Birkbeck, University of London38, Northwestern University39, Columbia University40, University of Virginia41, Veterans Health Administration42, University of California, San Diego43, University of Pennsylvania44, University of Zurich45
TL;DR: In this article, the authors start from the perspective that there are many types of studies that are important in this domain, e.g., feasibility, mechanistic, efficacy, and effectiveness, and suggest important routes forward, including greater interdisciplinary collaboration with individuals from domains that face related concerns.
Abstract: There is substantial interest in the possibility that cognitive skills can be improved by dedicated behavioral training. Yet despite the large amount of work being conducted in this domain, there is not an explicit and widely agreed upon consensus around the best methodological practices. This document seeks to fill this gap. We start from the perspective that there are many types of studies that are important in this domain—e.g., feasibility, mechanistic, efficacy, and effectiveness. These studies have fundamentally different goals, and, as such, the best-practice methods to meet those goals will also differ. We thus make suggestions in topics ranging from the design and implementation of control groups, to reporting of results, to dissemination and communication, taking the perspective that the best practices are not necessarily uniform across all study types. We also explicitly recognize and discuss the fact that there are methodological issues around which we currently lack the theoretical and/or empirical foundation to determine best practices (e.g., as pertains to assessing participant expectations). For these, we suggest important routes forward, including greater interdisciplinary collaboration with individuals from domains that face related concerns. Our hope is that these recommendations will greatly increase the rate at which science in this domain advances.
TL;DR: In this article, the authors argue that inertial forces generally constrict how TMTs perceive innovations, but that frame flexibility can overcome these constraints, increasing the likelihood of adoption and broadening the organization's innovation practices.
Abstract: Research Summary Why do incumbent firms frequently reject nonincremental innovations? Beyond technical, structural, or economic factors, we propose an additional factor: the degree of the top management team's (TMT) frame flexibility, i.e., their capability to cognitively expand an innovation's categorical boundaries and to cast the innovation as emotionally resonant with the organization's identity, competencies, and competitive boundaries. We argue that inertial forces generally constrict how TMTs perceive innovations, but that frame flexibility can overcome these constraints, increasing the likelihood of adoption and broadening the organization's innovation practices. We advance a theoretical model that relaxes the assumption that cognitive frames are static, showing how they become flexible via categorical positioning, and introduce a role for emotional frames that appeal to organizational members' sentiments and aspirations in innovation adoption. Managerial Summary Confronting a technological change is one of the most difficult challenges facing any incumbent firm. Technological transitions create pressure for leaders to reframe their mental models while continuing to develop existing capabilities and product category variants. Yet at key junctures in a product class and during technological change, a concrete definition of the firm's innovation boundaries and identity hold a firm hostage to its past. We show how a flexible cognitive frame—coupled with emotional framing—helps leaders and organization members become emotionally engaged in transformation efforts and, in turn, learn about executing nonincremental innovation over time. At technological transitions, perhaps there is no more important role for leaders than to expand their cognitive frames and to infuse these expanded frames with emotion.
TL;DR: An economical solid-state mechanochemical method to encapsulate enzymes during MOF synthesis is developed, allowing the encapsulation of enzymes into three prototypical robust MOFs while maintaining enzymatic biological activity.
Abstract: Metal-organic frameworks (MOFs) have recently garnered consideration as an attractive solid substrate because the highly tunable MOF framework can not only serve as an inert host but also enhance the selectivity, stability, and/or activity of the enzymes. Herein, we demonstrate the advantages of using a mechanochemical strategy to encapsulate enzymes into robust MOFs. A range of enzymes, namely β-glucosidase, invertase, β-galactosidase, and catalase, are encapsulated in ZIF-8, UiO-66-NH2, or Zn-MOF-74 via a ball milling process. The solid-state mechanochemical strategy is rapid and minimizes the use of organic solvents and strong acids during synthesis, allowing the encapsulation of enzymes into three prototypical robust MOFs while maintaining enzymatic biological activity. The activity of encapsulated enzyme is demonstrated and shows increased resistance to proteases, even under acidic conditions. This work represents a step toward the creation of a suite of biomolecule-in-MOF composites for application in a variety of industrial processes.
TL;DR: A new framework unifying existing definitions of point identification is given, and a zooful of different terms associated with identification that appear in the literature are summarized and compared.
Abstract: Over two dozen different terms for identification appear in the econometrics literature, including set identification, causal identification, local identification, generic identification, weak identification, identification at infinity, and many more. This survey (i) gives a new framework unifying existing definitions of point identification; (ii) summarizes and compares the zooful of different terms associated with identification that appear in the literature; and (iii) discusses concepts closely related to identification, such as normalizations and the differences in identification between structural models and causal, reduced form models.
TL;DR: The authors show that a full description of the unusual thermal behaviour in boron arsenide requires considering often-neglected four-phonon interactions, and reveal pressure as a knob to tune the interplay between the competing phonon scattering mechanisms in BAs and similar compounds.
Abstract: Recent experiments demonstrate that boron arsenide (BAs) is a showcase material to study the role of higher-order four-phonon interactions in affecting heat conduction in semiconductors. Here we use first-principles calculations to identify a phenomenon in BAs and a related material - boron antimonide, that has never been predicted or experimentally observed for any other material: competing responses of three-phonon and four-phonon interactions to pressure rise cause a non-monotonic pressure dependence of thermal conductivity, κ, which first increases similar to most materials and then decreases. The resulting peak in κ shows a strong temperature dependence from rapid strengthening of four-phonon interactions relative to three-phonon processes with temperature. Our results reveal pressure as a knob to tune the interplay between the competing phonon scattering mechanisms in BAs and similar compounds, and provide clear experimental guidelines for observation in a readily accessible measurement regime. Thermal properties of materials are driven by complex many-body interactions among thermal atomic vibrations called phonons. Here the authors show, from first-principles, that a full description of the unusual thermal behaviour in boron arsenide requires considering often-neglected four-phonon interactions.
TL;DR: A new strategy to encapsulate multiple dyes in-situ into nanocrystalline ZIF-8 pores to form an efficient dyes@MOF system is presented, which offers a new perspective not only for fine-tuning emission color within nanoporous dye@MOFs but also for fabricating MOF nanocrystals that are easily solution processable.
Abstract: Highly luminescent metal-organic frameworks (LMOFs) have received great attention for their potential use in energy-efficient general lighting devices such as white-light-emitting diodes (WLEDs); however, achieving strong emission with controllable color, especially high-quality white light, remains a considerable challenge. Herein, we present a new strategy to encapsulate in situ multiple dyes into nanocrystalline ZIF-8 pores to form an efficient dyes@MOF system. Using this strategy, we build three models, namely, multiphase single-shell dye@ZIF-8, single-phase single-shell dyes@ZIF-8, and single-phase multishell dyes@ZIF-8, to systematically and fine-tune the white emission color by varying the components and concentration of encapsulated dyes. The study of these three models demonstrates the importance of the multishell structure, which can effectively reduce the interactions such as Forster resonance energy transfer (FRET) between encapsulated dyes. This energy transfer would otherwise be unavoidable in a single-shell setting, which often reduces the efficiency of white-light emission in the dyes@MOF system. This approach offers a new perspective not only for fine-tuning the emission color within nanoporous dyes@MOFs but also for fabricating MOF nanocrystals that are easily solution-processable. The strategy may also facilitate the development of other types of MOF-guest nanocomposite systems.
TL;DR: In this article, the authors use a structural metaphor of the PCAOB inspection as a judicial "trial", where inspectors have the power to repeatedly "subpoena, interrogate, and return a "verdict" on the firm (auditor); those judged as "guilty" require supervised "probation".
Abstract: The objective of our article is to obtain a better understanding of how auditors anticipate the potential for PCAOB inspection, experience the inspection, cope with the consequences of the inspection, and understand the PCAOB's influence within the context of professionalism. We use a qualitative approach that uses both surveys (55) and interviews (20) of auditors (of varying rank and firm) across a five‐year period (2012–2017). Respondents suggest that PCAOB inspectors are powerful, representing the “prosecution,” “judge,” and “jury” of the auditing profession. We therefore use a structural metaphor of the PCAOB inspection as a judicial “trial.” By controlling the criteria used to evaluate performance, inspectors have the power to repeatedly “subpoena,” “interrogate,” and return a “verdict” on the firm (auditor); those judged as “guilty” require supervised “probation.” This process is perceived as having improved audit quality but at a cost. Passing an inspection is so important that auditors (firms) have resorted to impression management strategies and “functionally stupid” work practices (e.g., excessive documentation, a decrease in critical thinking as a result of a “box ticking” approach to auditing). Furthermore, some respondents believe that being a good auditor has come at the expense of being a good accountant; the emphasis on audit process and concurrent de‐emphasis on technical accounting could ultimately lead to audits themselves falling short. In addition, it is evident that inspectors and auditors differ in their perceptions of risk, likely manifesting because inspectors are standards‐focused while auditors (firms) are methodology‐focused. Finally, the inspection process has created excessive stress and tension, beyond budget and fee pressures, which some auditors perceive as affecting the pool of talented auditors that firms may be able to attract and retain in the future. Inspections du PCAOB : le « tribunal » des cabinets d'expertise comptable Les auteurs ont pour but d'acquerir une meilleure comprehension de la facon dont les auditeurs anticipent la possibilite d'une inspection du PCAOB, subissent cette inspection, en gerent les consequences et percoivent l'influence du PCAOB dans le contexte du professionnalisme. Ils emploient une methode qualitative faisant appel a la fois a des sondages (55) et a des entrevues (20) menes aupres d'auditeurs (d’echelons et de cabinets divers), sur une periode de cinq ans (2012 a 2017). Les participants estiment que les inspecteurs du PCAOB ont beaucoup de pouvoir, puisqu'ils sont a la fois « incriminateurs », « juges » et « jures » a l’egard de la profession d'audit. Recourant a une metaphore structurelle, les auteurs associent donc l'inspection du PCAOB a un « proces » devant un tribunal. En controlant les criteres servant a evaluer la performance, les inspecteurs ont le pouvoir de « citer a comparaitre », d’« interroger » et de rendre un « verdict » a l’egard du cabinet (de l'auditeur) ; les intimes qui sont juges « coupables » doivent se soumettre a une « probation » sous surveillance. Ce processus, estime‐t‐on, a ameliore la qualite de l'audit, mais cette amelioration a un cout. L’epreuve de l'inspection est une experience d'une telle importance que les auditeurs (les cabinets) se livrent a des strategies de gestion des relations et a des pratiques de travail deraisonnables sur le plan fonctionnel (par exemple, en abusant de la documentation et en adoptant une methode d'audit systematisee — suivant l'ordre des « cases a cocher » — qui compromet leur sens critique). En outre, certains participants sont d'avis que les competences en audit se perfectionnent aux depens des competences en comptabilite ; le fait de mettre l'accent sur le processus d'audit et d'accorder concurremment moins d'importance a la technique comptable pourrait, en definitive, nuire a la qualite meme des audits. Au surplus, de toute evidence, les inspecteurs et les auditeurs ont une perception differente du risque qui tient vraisemblablement au fait que les inspecteurs se concentrent sur les normes alors que les auditeurs (les cabinets) se preoccupent de la methodologie. Enfin, le processus d'inspection engendre un exces de stress et de tension, au‐dela des pressions relatives au budget et aux honoraires, ce qui, du point de vue de certains auditeurs, a une incidence sur le bassin d'auditeurs talentueux que les cabinets pourraient reussir a recruter et a maintenir en poste dans l'avenir.