Electrosynthesis is a popular, green alternative to traditional organic methods. Understanding the mechanisms is not trivial yet is necessary to optimize reaction processes. To this end, a multitude ...of analytical tools is available to identify and quantitate reaction products and intermediates. The first portion of this review serves as a guide that underscores electrosynthesis fundamentals, including instrumentation, electrode selection, impacts of electrolyte and solvent, cell configuration, and methods of electrosynthesis. Next, the broad base of analytical techniques that aid in mechanism elucidation are covered in detail. These methods are divided into electrochemical, spectroscopic, chromatographic, microscopic, and computational. Technique selection is dependent on predicted reaction pathways and electrogenerated intermediates. Often, a combination of techniques must be utilized to ensure accuracy of the proposed model. To conclude, future prospects that aim to enhance the field are discussed.
An efficient protocol for the synthesis of sulfonamides via the electrochemical oxidative amination of sodium sulfinates has been developed. The chemistry proceeds in a simple undivided cell ...employing a substoichiometric amount of NH4I that serves both as a redox catalyst and a supporting electrolyte; in this manner additional conducting salt is not required. A wide range of substrates, including aliphatic or aromatic secondary and primary amines, as well as aqueous ammonia, proved to be compatible with the protocol. Scale-up was possible, thereby demonstrating the practicality of the approach. The electrolytic process avoids the utilization of external oxidants or corrosive molecular iodine and therefore represents an environmentally benign means by which to achieve the transformation.
An electrochemically promoted coupling of benzoxazoles and amines has been developed, leading directly to the formation of 2-aminobenzoxazoles. The chemistry utilizes catalytic quantities of a ...tetraalkylammonium halide redox catalyst and is carried out under constant current conditions in a simple undivided cell. The use of excess chemical oxidant or large amounts of supporting electrolyte is avoided. This greatly simplifies the workup and isolation process and leads to a reduction in waste.
Exemplar-similarity models such as the exemplar-based random walk (EBRW) model (Nosofsky & Palmeri, 1997b) were designed to provide a formal account of multidimensional classification choice ...probabilities and response times (RTs). At the same time, a recurring theme has been to use exemplar models to account for old-new item recognition and to explain relations between classification and recognition. However, a major gap in research is that the models have not been tested on their ability to provide a theoretical account of RTs and other aspects of performance in the classic Sternberg (1966) short-term memory-scanning paradigm, perhaps the most venerable of all recognition-RT tasks. The present research fills that gap by demonstrating that the EBRW model accounts in natural fashion for a wide variety of phenomena involving diverse forms of short-term memory scanning. The upshot is that similar cognitive operating principles may underlie the domains of multidimensional classification and short-term old-new recognition. (Contains 11 tables, 14 figures and 11 footnotes.)
In the study of perceptual categorization, a key distinction is made between separable and integral dimensions. Separable dimensions are easy to attend in isolation, while integral dimensions are ...not. Little et al. (2016) showed that when trial-by-trial responses are analyzed, a consistent pattern of sequential effects was found in a modified Garner paradigm using integral-dimension stimuli. The present experiments investigated whether these pronounced sequential effects are also found with separable-dimension stimuli. Four experiments using two different types of separable dimensions were conducted. The results indicated that similar patterns of sequential effects were present for separable-dimension stimuli, but, unlike for integral dimensions, the effect of a change in the irrelevant dimension in the filtering task was not found. Further, for separable dimensions, the overall pattern of sequential effects did not vary between the Garner tasks (i.e., control, correlated, and filtering). To explain these results, we fit a sequence-sensitive exemplar model and compared the fits of this model to a novel sequence-sensitive feature model, in which only the relevant feature influences the categorization decision. We found that the full exemplar model provided a more compelling account of both our separable dimension data and the integral dimension data of Little et al. (2016). These findings provide a more complete understanding of perceptual categorization and add to the growing body of literature on the prevalence and critical implications of strong sequential effects in cognitive tasks.
Novelty Rejection in Episodic Memory Osth, Adam F.; Zhou, Aspen; Lilburn, Simon D. ...
Psychological review,
04/2023, Letnik:
130, Številka:
3
Journal Article
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Episodic memory theories have postulated that in recognition, a probe is accepted or rejected on the basis of its global similarity to studied items. Mewhort and Johns (2000) directly tested global ...similarity predictions by manipulating the feature compositions of probes-novelty rejection was facilitated when probes contained novel features even when other features strongly matched, an advantage dubbed the extralist feature effect, which greatly challenged global matching models. In this work, we conducted similar experiments using continuously valued separable- and integral-dimension stimuli. Analogs of extralist lures were constructed where one stimulus dimension contained a value that was more novel than the other dimensions, whereas overall similarity was equated to another class of lures. Facilitated novelty rejection for lures with extralist features was only found for separable-dimension stimuli. While integral-dimension stimuli were well described by a global matching model, the model failed to account for extralist feature effects with separable-dimension stimuli. We applied global matching models-including variants of the exemplar-based linear ballistic accumulator-that employed different means of novelty rejection afforded by separable-dimension stimuli, including decisions based on the global similarity of the individual dimensions and selective attention being directed toward novel probe values (a diagnostic attention model). While these variants produced the extralist feature effect, only the diagnostic attention model succeeded in providing a sufficient account of all of the data. The model was also able to account for extralist feature effects in an experiment with discrete features similar to those from Mewhort and Johns (2000).
We describe a method to generate alkylidene carbenes via tetramethylammonium-fluoride-induced desilylation of silyl vinyl iodides. The reversible carbene generation from an iodovinyl anion enabled us ...to unearth mechanistic aspects of the trimethylenemethane (TMM) diyl cyclization reaction that could not be explored via previous methods. We observed that a slow diyl–diylophile cycloaddition can induce the reversible formation of an alkylidene carbene from the TMM diyl intermediate via a retro-cyclopropanation at ambient temperature.
Systems factorial technology (SFT) is a theoretically derived methodology that allows for strong inferences to be made about underlying processing architectures (e.g., whether processing occurs in a ...pooled, coactive fashion or in serial or in parallel). Measures of mental architecture using SFT have been restricted to the use of error-free response times (RTs). In this article, through formal proofs and demonstrations, we extended the measure of architecture, the survivor interaction contrast (SIC), to RTs conditioned on whether they are correct or incorrect. We show that so long as an ordering relation (between stimulus conditions of different difficulty) is preserved, we learn that the canonical SIC predictions result when exhaustive processing is necessary and sufficient for a response. We further prove that this ordering relation holds for the popular Wiener diffusion model for both correct and error RTs but fails under some classes of a Poisson counter model, which affords a strong potential experimental test of the latter class versus the others. Our exploration also serves to point to the importance of detailed studies of how errors are made in perceptual and cognitive tasks.
Cultures around the world organize stars into constellations, or asterisms, and these groupings are often considered to be arbitrary and culture specific. Yet there are striking similarities in ...asterisms across cultures, and groupings such as Orion, the Big Dipper, the Pleiades, and the Southern Cross are widely recognized across many different cultures. Psychologists have informally suggested that these shared patterns are explained by Gestalt laws of grouping, but there have been no systematic attempts to catalog asterisms that recur across cultures or to explain the perceptual basis of these groupings. Here, we compiled data from 27 cultures around the world and found that a simple computational model of perceptual grouping accounts for many of the recurring cross-cultural asterisms. Our results suggest that basic perceptual principles account for more of the structure of asterisms across cultures than previously acknowledged and highlight ways in which specific cultures depart from this shared baseline.
Abstract Graphical perception is an important part of the scientific endeavour, and the interpretation of graphical information is increasingly important among educated consumers of popular media, ...who are often presented with graphs of data in support of different policy positions. However, graphs are multidimensional and data in graphs are comprised not only of overall global trends but also local perturbations. We presented a novel function estimation task in which scatterplots of noisy data that varied in the number of data points, the scale of the data, and the true generating function were shown to observers. 170 psychology undergraduates with mixed experience of mathematical functions were asked to draw the function that they believe generated the data. Our results indicated not only a general influence of various aspects of the presented graph (e.g., increasing the number of data points results in smoother generated functions) but also clear individual differences, with some observers tending to generate functions that track the local changes in the data and others following global trends in the data.
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