Current views posit that forming and retrieving memories of ongoing events influences action control. However, the organizational structure of these memories, or event files, remains unclear. The ...hierarchical coding view posits a hierarchical structure, wherein task sets occupy a high level of the hierarchy. Here, the contents of an event file can be retrieved only if the task set repeats. In contrast, the binary coding view posits a nonhierarchical structure, which consists of a collection of independent, binary bindings between different feature pairs. In this view, repeating an abstract feature from a previous event (e.g., the previous trial's S-R mapping) triggers the retrieval of the associated feature from the same binding (e.g., the previous trial's congruency) even if the task set changes. To distinguish between these views, we investigated the nature of task set boundaries for the congruency sequence effect (CSE), an index of adaptive control that reflects event file formation and retrieval. Specifically, we investigated whether or not a CSE appears when the task set changes but the previous trial's S-R mapping repeats. Three experiments involving a cross-modal prime-probe task yielded a CSE under these conditions and ruled out alternative explanations. These findings show that the typical binary structure of event files generalizes from concrete features (e.g., colors and locations) to abstract features (e.g., S-R mappings and task sets). Therefore, contrary to the hierarchical coding view, they provide a nonhierarchical explanation of task set boundaries for the CSE.
People respond more slowly in two-choice tasks when
either
a previous stimulus feature
or
the previous response repeats in partial repetition trials than when (a) both repeat in complete repetition ...trials or (b) both alternate in complete alternation trials. The binding account posits that such
partial repetition costs
index a memory-retrieval conflict, which occurs because partial repetition trials trigger the retrieval of a previous stimulus feature or response that conflicts with a current stimulus feature or response. However, such costs may additionally reflect a simple decision-making heuristic that uses the repetition or alternation of a previous stimulus feature as a “signal” to bias response selection toward a repetition or an alternation of the previous response. To determine whether signaling contributes to partial repetition costs, we employed a four-choice task. Here, a stimulus feature repetition still signals a response repetition, but a stimulus feature alternation does not signal which of the three remaining responses to make. Consistent with an influence of signaling, we sometimes observed complete repetition advantages without complete alternation advantages. Exploratory analyses further revealed that partial repetition costs measured more broadly were smaller in the four-choice task than in a matched two-choice task. These findings suggest that partial repetition costs index a mixture of binding and signaling.
Cognitive control processes that enable purposeful behavior are often context-specific. A teenager, for example, may inhibit the tendency to daydream at work but not in the classroom. However, the ...nature of contextual boundaries for cognitive control processes remains unclear. Therefore, we revisited an ongoing controversy over whether such boundaries reflect (a) an attentional reset that occurs whenever a context-defining (e.g., sensory) feature changes or (b) a disruption of episodic memory retrieval that occurs only when the updated context-defining feature is linked to a different task set. To distinguish between these hypotheses, we used a cross-modal distractor-interference task to determine precisely when changing a salient context-defining feature-the sensory modality in which task stimuli appear-bounds control processes underlying the congruency sequence effect (CSE). Consistent with the task set hypothesis, but not with the attentional reset hypothesis, Experiments 1 and 2 revealed that changing the sensory modality in which task stimuli appear eliminates the CSE only when the task structure enables participants to form modality-specific task sets. Experiment 3 further revealed that such "modality-specific" CSEs are associated with orienting attention to the sensory modality in which task stimuli appear, which may facilitate the formation of a modality-specific task set. These findings support the view that task sets serve as boundaries for the CSE.
Public Significance Statement
Cognitive control processes that enable purposeful behavior are often context-specific. For example, a child who recruits control to avoid getting into a fight in the classroom may not recruit such control on the playground. In the present study, we investigated the nature of such "contextual boundaries" for control. We found that these boundaries reflect switching between distinct task sets that form when control processes assign different context-defining features to different events or episodes, rather than switching between the features themselves. This finding informs an ongoing controversy regarding the boundaries of cognitive control.
In this work, we prepared, isolated, and structurally characterized a zirconium complex having a terminally bound imide motif, (PN)2Zr≡NH (PN– = (N-(2-iPr2P-4-methylphenyl)-2,4,6-trimethylanilide)), ...along with the zirconium nitride complex {(PN)2Zr≡Nμ2-Li(THF)}2. (PN)2Zr≡NH was prepared by reduction of trans-(PN)2Zr(N3)2 with KC8. Isotopic labeling and spectroscopic studies were conducted using the respective 15N enriched isotopologues, whereas solid-state structural studies confirmed some of the shortest Zr≡N distances known to date (Zr≡NH, 1.830(3) Å; Zr≡N–, 1.822(2) Å). It was found that the nitride in {(PN)2Zr≡Nμ2-Li(THF)}2 is super basic and in the range of −36 to −43 pK b units. Computational studies have been applied to probe the bonding and structure for this new class of zirconium–nitrogen multiple bonds.
In the last seven years, chemistry of the phosphaethynolate reagent, Na(OCP)(1,4‐dioxane)2.5, has seen a surge in organic and inorganic chemistry—A renaissance to cyanate chemistry in a new guise. ...Whereas there have been many reports of main group reactivity with OCP−, largely from group 14, in more recent times the use of electropositive metals has garnered significant interest given their ability to disguise in various oxidation states. Herein, we report and discuss advances in such studies of OCP− with early transition metal and f‐block metal scaffolds.
Alternative chemical avenues: In the last few years, chemistry of the phosphaethynolate reagent, OCP−, has seen a surge in organic and inorganic regimes—A renaissance to cyanate chemistry in a new guise. To this end, the use of electropositive metals has garnered significant interest given their ability to disguise in various oxidation states. Herein, we discuss advances in such studies of OCP‐ with early transition metal and f‐block metal scaffolds.
Competencies ensure public health students and professionals have the necessary knowledge, skills, values, and behaviours to do their jobs effectively. Public health is a dynamic and complex field ...requiring robust competency statements and frameworks that are regularly renewed. Many countries have public health competencies, but there has been no evidence synthesis on how these are developed. Our research aim was to synthesize the extent and nature of the literature on approaches and best practices for competencies statement and framework development in the context of public health, including identifying the relevant literature on approaches for developing competency statements and frameworks for public health students and professionals using a scoping review; and, synthesizing and describing approaches and best practices for developing public health competency statements and frameworks using a thematic analysis of the literature identified by the scoping review. We conducted a scoping review and thematic analysis of the academic and grey literature to synthesize and describe approaches and best practices for developing public health competency statements and frameworks. A systematic search of six databases uncovered 13 articles for inclusion. To scope the literature, articles were assessed for characteristics including study aim, design, methods, key results, gaps, and future research recommendations. Most included articles were peer-reviewed journal articles, used qualitative or mixed method design, and were focused on general, rather than specialist, public health practitioners. Thematic analysis resulted in the generation of six analytical themes that describe the multi-method approaches utilized in developing competency statements and frameworks including literature reviews, expert consultation, and consensus-building. There was variability in the transparency of competency framework development, with challenges balancing foundational and discipline-specific competencies. Governance, and intersectoral and interdisciplinary competency, are needed to address complex public health issues. Understanding approaches and best practices for competency statement and framework development will support future evidence-informed iterations of public health competencies.
The complex (nacnac)Ti(OAr)2(μ2:η2,η2‐P2) (1) is formed via reductive decarbonylation of the phosphaethynolate ion −OCP, which serves as a P atom source. Complex 1 is the first structurally ...characterized Group 4 transition metal P2 complex and its structure reveals the rhombic Ti2P2 core is essentially planar with short bond lengths suggesting some degree of multiple bonding character between the Ti–P and P–P sites. Computational studies of 1 provide an understanding of the Ti2P2 core as well as the origin of the highly downfield 31P NMR spectroscopic signal.
The first structurally characterized Group 4 transition metal P2 complex, namely (nacnac)Ti(OAr)2(μ2:η2,η2‐P2) (1), contains a rhombic, essentially planar Ti2P2 core with short bond lengths suggesting some degree of multiple bonding character between the Ti–P and P–P sites. Complex 1 is formed via reductive decarbonylation of the phosphaethynolate ion −OCP, which serves as a P atom source. Computational studies of 1 provide an understanding of the Ti2P2 core as well as the origin of the highly downfield 31P NMR spectroscopic signal.
Adapting flexibly to recent events is essential in everyday life. A robust measure of such adaptive behavior is the congruency sequence effect (CSE) in the prime-probe task, which refers to a smaller ...congruency effect after incongruent trials than after congruent trials. Prior findings indicate that the CSE in the prime-probe task reflects control processes that modulate response activation after the prime onsets but before the probe appears. They also suggest that similar control processes operate even in a modified prime-probe task wherein the initial prime is a relevant target, rather than merely a distractor. Because adaptive behavior frequently occurs in the absence of irrelevant stimuli, the present study investigates the nature of the control processes that operate in this modified prime-probe task. Specifically, it investigates whether these control processes modulate only the response cued by the prime (response-specific control) or also other responses (response-general control). To make this distinction, we employed a novel variant of the modified prime-probe task wherein primes and probes are mapped to different responses (i.e., effectors), such that only response-general control processes can engender a CSE. Critically, we observed a robust CSE in each of 2 experiments. This outcome supports the response-general control hypothesis. More broadly, it suggests that the control processes underlying the CSE overlap with general mechanisms for adapting to sequential dependencies in the environment.
Public Significance Statement
Adapting flexibly to recent events is a crucial aspect of cognitive control. For example, after discovering that a passenger's directions for reaching one destination are incorrect, a driver may become cautious about following the same passenger's directions to a second destination. It remains unclear, however, exactly how control processes adapt flexibly to whether or not advance information (e.g., driving directions) was recently useful. More specifically, it remains unclear whether they adapt solely by modulating the response that advance information currently cues (e.g., by inhibiting a "turn left" response that a passenger suggests) or also by modulating a different response (e.g., by activating an alternative "turn right" response). Our findings support the latter possibility and thereby distinguish between competing accounts of adaptive control.
The first example of the OCPPCO ligand, diisophosphaethynolate, is reported via reductive coupling of a Sc−OCP precursor. Upon reduction with KC8, isolation of the dinuclear complex, namely ...K(OEt2)2(nacnac)Sc(OAr)2(OCPPCO), is observed, leading to a unique motif OCPPCO4−, stabilized by two scandium centers. Detailed NMR spectra of all complexes as well as IR and single crystal X‐ray studies were obtained to fully elucidate the nature of these complexes in solution as well as in the solid state. Theory is combined to probe the electronic structure and orbitals responsible for the bonding interactions in the Sc−OCPPCO−Sc skeleton but also to compare to the linear mode observed in the precursor.
The OCPPCO ligand, diisophosphaethynolate, formed by reductive coupling of a Sc−OCP precursor, is reported. Upon reduction with KC8, isolation of the dinuclear complex, K(OEt2)2(nacnac)Sc(OAr)2(OCPPCO), is observed, leading to a unique motif OCPPCO4− stabilized by two scandium centers. NMR, IR, and X‐ray diffraction were used to study these complexes in solution as well as in the solid state.
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