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ariations on the Bergman Cyclization Theme: Electrocyclizations of Ionic Penta-, Hepta-, and Octadiy
No full textThe Bergman cyclization of (Z)-hexa-3-ene-1,5-diyne to form the aromatic diradical p-benzyne has garnered attention as a potential antitumor agent due to its relatively low cyclization barrier and the stability of the resulting diradical. Here, we present a theoretical investigation of several ionic extensions of the fundamental Bergman cyclization: electrocyclizations of the penta-1,4-diyne anion, hepta-1,6-diyne cation, and octa-1,7-diyne dication, leveraging the spin-flip formulation of the equation-of-motion coupled cluster theory with single and double substitutions (EOM-SF-CCSD). Though the penta-1,4-diyne anion exhibits a large cyclization barrier of +66 kcal mol–1, cyclization of both the hepta-1,6-diyne cation and octa-1,7-diyne dication along a previously unreported triplet pathway requires relatively low energy. We also identified the presence of significant aromaticity in the triplet diradical products of these two cationic cyclizations
Conducting research at primarily undergraduate institutions
No full textUndergraduate research and education are critical parts of the scientific ecosystem. Professors at primarily undergraduate institutions (PUIs) bear responsibility for molding young scientists while carrying out high quality research. In this Voices piece, researchers offer inspiring replies to the following prompt: in your role as a professor, what are the challenges and opportunities when conducting research at a PUI
Mechanistic Elucidation of Nanomaterial-Enhanced First-Generation Biosensors Using Probe Voltammetry of an Enzymatic Reaction
No full textThe incorporation of nanomaterials (NMs) into biosensing schemes is a well-established strategy for gaining signal enhancement. With electrochemical biosensors, the enhanced performance achieved from using NMs is often attributed to the specific physical properties of the chosen nanocomponents, such as their high electronic conductivity, size-dependent functionality, and/or higher effective surface-to-volume ratios. First generation amperometric biosensing schemes, typically utilizing NMs in conjunction with immobilized enzyme and semi-permeable membranes, can possess complex sensing mechanisms that are difficult to study and challenging to understand beyond the observable signal enhancement. This study shows the use of an enzymatic reaction between xanthine (XAN) and xanthine oxidase (XOx), involving multiple electroactive species, as an electrochemical redox probe tool for ascertaining mechanistic information at and within the modified electrodes used as biosensors. Redox probing using components of this enzymatic reaction are demonstrated on two oft-employed biosensing approaches and commonly used NMs for modified electrodes: gold nanoparticle doped films and carbon nanotube interfaces. In both situations, the XAN metabolism voltammetry allows for a greater understanding of the functionality of the semipermeable membranes, the role of the NMs, and how the interplay between the two components creates signal enhancement
“Not what we signed up for”: Nurse shortages, physician scarcity, and time for collective bargaining?
No full textThe amount of distress and disengagement among many nurses and physicians has reached concerning levels in recent years. The result has been acute nurse shortages, significant increases in travel nursing, more physicians working fewer hours and retiring early, and urgent calls for change and reform. This analysis surveys many of the leading systemic contributors to nurse and physician demoralization. As the healthcare sector continues to experience more consolidation and increased investment by private equity and other corporate interests, physicians are increasingly becoming employees with similar forms of employment arrangements and pressures that nurses have had for decades. They are also becoming employees of the same larger health systems, hospitals, and corporate employers. These trends are leading to a convergence in the kind and intensity of pressures and problems that nurses and physicians face. As more medical residents and fellows increasingly turn to unionization and as growing numbers of nurses have gone on strike, both professions should consider the potential benefits of joining forces for the purposes of maintaining the autonomy they have left and to push for better conditions both for themselves and the patients for whom they care
Nuestra Clarice: Un proyecto latinoamericano
No full textEl primer esbozo del proyecto de investigación colaborativa Nuestra Clarice surgió, como tantas veces ocurre con Lispector, inesperadamente. En una primavera porteña en octubre de 2019—cuando era imposible imaginar lo que nos tocaría vivir unos pocos meses después—el azar y las amistades compartidas resultaron en el encuentro de las dos profesoras que se lanzaron a idear este proyecto. Veníamos de experiencias clariceanas diferentes, y no tanto, porque cuando se juntan seres que han entrado para quedarse en el universo de Lispector, los códigos, las señales,y los gestos se cruzan sin necesidad de encontrar explicación alguna. Quizás también nos animaba el espíritu revolucionario y feminista que nos venía atravesando desde los últimos años—que se manifestó,por ejemplo, a ambos lados de la cordillera, con la legalización del aborto en Argentina y la “primavera chilena”. Entre mate y facturas, volvió a cobrar vida una idea que había soñado Teresa Montero, biógrafa carioca de Clarice Lispector. Recuperar aClarice desde y para Latinoamérica, esa Latinoamérica que ya la había acogido de múltiples maneras a lo largo de su carrera y que históricamente aparecía opacada por la recuperación de Lispector en el norte angloparlante. Desarmar ese axis norte-sur fue el primer gesto feminista decolonial de este proyecto que reúne trayectos de investigación en América Latina sobre la obra de Clarice Lispector en español y pone en diálogo a críticxs, traductorxs, editorxs y artistas. La “dependencia intelectual euronorcéntrica”,de la que habla Ochy Curiel al interpelar las jerarquías que aún asolan a los feminismos latinoamericanos, nos ha atravesado en la labor crítica y en la práctica de lectura cuando nos acercamos a la figura de Lispector. No solo se ha priorizado y sobrevalorado el corpus de textos académicos salidos en inglés de los espacios norteamericanos—junto con el “fenómeno Lispector” propiciado por la editorial neoyorquina New Directions, responsable también del “fenómeno Bolaño”—sino que además no se ha generado dentro de Latinoamérica suficiente intercambio entre diferentes lugares geopolíticosatravesados, también, por dinámicas coloniales
mRedditSum: A Multimodal Abstractive Summarization Dataset of Reddit Threads with Images
No full textThe growing number of multimodal online discussions necessitates automatic summarization to save time and reduce content overload. However, existing summarization datasets are not suitable for this purpose, as they either do not cover discussions, multiple modalities, or both. To this end, we present mRedditSum, the first multimodal discussion summarization dataset. It consists of 3,033 discussion threads where a post solicits advice regarding an issue described with an image and text, and respective comments express diverse opinions. We annotate each thread with a human-written summary that captures both the essential information from the text, as well as the details available only in the image. Experiments show that popular summarization models—GPT-3.5, BART, and T5—consistently improve in performance when visual information is incorporated. We also introduce a novel method, cluster-based multi-stage summarization, that outperforms existing baselines and serves as a competitive baseline for future work
Part VI - Shared Forms, Distinct Functions
No full textIn a 2001 article in Etruscan Studies, Jodi Magness used details of funeral bed design to suggest that “during the seventh century, small groups of Near Eastern immigrants … settled in southern Etruria and were assimilated with the local population” (Magness Reference Magness2001: 80). She argued that the curved headrests of some Etruscan rock tombs were so similar to those in Judaean tombs that there must have been direct connections between Etruscan and Near Eastern elites, beyond trade contacts or movements of craftspeople, that the Etruscan rock-cut beds were designed to fit the needs and tastes of Near Eastern immigrant elites, and that they reflect the transmission of ideology as well as the movement of people. A problem with this argument, however, is the lack of precise resemblance between the curved headrests of Etruscan tombs and those in the Judaean tombs. In fact, much closer parallels for the Etruscan design can be found in Anatolia – in Phrygian rock-cut tombs as well as on funeral couches built from stone slabs in Lydian tumulus chambers. This chapter explores those similarities and others between funerary beds in Etruria and Anatolia, but not with the purpose of establishing population movement or cultural dependence; rather, it argues that while the similarities do reflect shared furniture styles, the uses to which those furniture styles were put differed, and those differences suggest cultural distinction rather than assimilation
Is affective polarization driven by identity, loyalty, or substance?
No full textPartisan Americans like members of their own party more than members of the opposing party. Scholars often interpret this as evidence that party identity or loyalty influence interpersonal affect. First, we reassess previous studies and demonstrate that prior results are also consistent with what we would predict if people cared only about policy agreement. Next, we demonstrate the difficulty of manipulating perceptions of party identity without also manipulating beliefs about policy agreement and vice versa. Finally, we show that partisans care much more about policy agreement than they do about party loyalty when the two come into conflict. Our analyses suggest that partisan Americans care about policy agreement; we have little convincing evidence that they care about partisan identity or loyalty per se, and scholars will have to find new research designs if they want to convincingly estimate the effects of identity or loyalty independent of policy substance