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The reactivity of a [V^V] alkylidyne with unsaturated substrates such as NCR (R = Ad or Ph) and PCAd leads to the formation of rare transition metal complexes featuring an α-aza-vanadacyclobutadiene and a β-phospha-vanadacyclobutadiene moieties. 

The British landscape painter John Constable is considered foundational for the Realist movement in 19th-century European painting. Constable’s painted skies, in particular, were seen as remarkably accurate by his contemporaries, an impression shared by many viewers today. Yet, assessing the accuracy of realist paintings like Constable’s is subjective or intuitive, even for professional art historians, making it difficult to say with certainty what set Constable’s skies apart from those of his contemporaries. Our goal is to contribute to a more objective understanding of Constable’s realism. We propose a new machine-learning-based paradigm for studying pictorial realism in an explainable way. Our framework assesses realism by measuring the similarity between clouds painted by artists noted for their skies, like Constable, and photographs of clouds. The experimental results of cloud classification show that Constable approximates more consistently than his contemporaries the formal features of actual clouds in his paintings. The study, as a novel interdisciplinary approach that combines computer vision and machine learning, meteorology, and art history, is a springboard for broader and deeper analyses of pictorial realism. 

Abstract Described here is a direct entry to two examples of 3d transition metal catalysts that are active for the cyclic polymerization of phenylacetylene, namely, [(BDI)M{κ²‐C,C‐(Me₃SiC₃SiMe₃)}] (2‐M) (BDI=[ArNC(CH₃)]₂CH⁻, Ar=2,6‐ⁱPr₂C₆H₃;M=Ti, V). Catalysts are prepared in one step by the treatment of [(BDI)MCl₂] (1‐M,M=Ti,V) with 1,3‐dilithioallene [Li₂(Me₃SiC₃SiMe₃)]. Complexes2‐Mhave been spectroscopically and structurally characterized and the polymers that are catalytically formed from phenylacetylene were verified to have a cyclic topology based on a combination of size‐exclusion chromatography (SEC) and intrinsic viscosity studies. Two‐electron oxidation of2‐Vwith nitrous oxide (N₂O) cleanly yields a [V^V] alkylidene‐alkynyl oxo complex [(BDI)V(=O){κ¹‐C‐(=C(SiMe₃)CC(SiMe₃))}] (3), which lends support for how this scaffold in2‐Mmight be operating in the polymerization of the terminal alkyne. This work demonstrates how alkylidynes can be circumvented using 1,3‐dianionic allene as a segue into M−C multiple bonds. 

Abstract BackgroundTo increase teachers’ capacity to implement high-quality instructional materials with fidelity in their classrooms through a video-based professional learning cycle, the Analyzing Instruction in Mathematics Using the Teaching for Robust Understanding framework (AIM–TRU) research–practice partnership was formed. Drawing upon the design-based research paradigm, AIM–TRU created the initial design for the professional learning cycle and wanted to engage in continued iterative redesign as the year progressed. This necessitated a method, common among those who adjust their designs when applying them in context, by which to document and justify changes made over time to our model. The research contained in this article used qualitative methods to articulate and test the design underlying our professional learning cycle by advancing conjecture mapping, a device by which the embodiments of the design are made transparent to be analyzed in practice. ResultsThe initial design conjectures and activity structures teachers engaged in through our model of professional learning were refined to address three themes that emerged. Firstly, it was found that the ways participants engaged with the mathematics of the lesson were underwhelming, in large part, because our own definition of what rich talk around mathematics should entail was lacking in details such as the mathematical objects in the lesson, the presence of multiple solution pathways, or the various representations that students could use. Second, talk structures did not always allow for equitable exchanges among all teachers. Finally, activity structures did not encourage teachers to delve deeply into the mathematics so they could perceive the lesson as a coherent piece of their own classroom curriculum. Our design conjectures and activity structures were revised over the course of the year. ConclusionsOur use of conjecture mapping allowed us to address the concern with research–practice partnerships that they should develop and utilize tools that make the systemic inquiry they engage in transparent, allowing for other researchers, practitioners, and stakeholders to see the complete design process and make use of the findings for their local context. Implications for this process as a tool for those who pilot and scale professional development are raised and addressed. 

Abstract Chemoselective cross-coupling of phenol derivatives is valuable for generating products that retain halides. Here we discuss recent developments in selective cross-couplings of chloroaryl phenol derivatives, with a particular focus on reactions of chloroaryl tosylates. The first example of a C–O-selective Ni-catalyzed Suzuki–Miyaura coupling of chloroaryl tosylates is discussed in detail. 1 Introduction 2 Density Functional Theory Studies on Oxidative Addition at Nickel(0) 3 Stoichiometric Oxidative Addition Studies 4 Development of a Tosylate-Selective Suzuki Coupling 5 Conclusion and Outlook 

Abstract Differing interpretations of geophysical and geologic data have led to debate regarding continent-scale plate configuration, subduction polarity, and timing of collisional events on the western North American plate margin in pre–mid-Cretaceous time. One set of models involves collision and accretion of far-traveled “exotic” terranes against the continental margin along a west-dipping subduction zone, whereas a second set of models involves long-lived, east-dipping subduction under the continental margin and a fringing or “endemic” origin for many Mesozoic terranes on the western North American plate margin. Here, we present new detrital zircon U-Pb ages from clastic rocks of the Rattlesnake Creek and Western Klamath terranes in the Klamath Mountains of northern California and southern Oregon that provide a test of these contrasting models. Our data show that portions of the Rattlesnake Creek terrane cover sequence (Salt Creek assemblage) are no older than ca. 170–161 Ma (Middle–early Late Jurassic) and contain 62–83% Precambrian detrital zircon grains. Turbidite sandstone samples of the Galice Formation are no older than ca. 158–153 Ma (middle Late Jurassic) and contain 15–55% Precambrian detrital zircon grains. Based on a comparison of our data to published magmatic and detrital ages representing provenance scenarios predicted by the exotic and endemic models (a crucial geologic test), we show that our samples were likely sourced from the previously accreted, older terranes of the Klamath Mountains and Sierra Nevada, as well as active-arc sources, with some degree of contribution from recycled sources in the continental interior. Our observations are inconsistent with paleogeographic reconstructions that are based on exotic, intra-oceanic arcs formed far offshore of North America. In contrast, the incorporation of recycled detritus from older terranes of the Klamath Mountains and Sierra Nevada, as well as North America, into the Rattlesnake Creek and Western Klamath terranes prior to Late Jurassic deformation adds substantial support to endemic models. Our results suggest that during long-lived, east-dipping subduction, the opening and subsequent closing of the marginal Galice/Josephine basin occurred as a result of in situ extension and subsequent contraction. Our results show that tectonic models invoking exotic, intra-oceanic archipelagos composed of Cordilleran arc terranes fail a crucial geologic test of the terranes’ proposed exotic origin and support the occurrence of east-dipping, pre–mid-Cretaceous subduction beneath the North American continental margin.