Incumbency and self-uncertainty: when prototypical leaders lose their advantage.

Research on how uncertainty affects the preference for prototypical over non-prototypical leaders has produced mixed results. To understand these discrepancies, two studies explored leader status (prospective versus incumbent) as a potential moderator. Participants reported levels of self-uncertainty (Study 1) or were primed with high versus low self-uncertainty (Study 2) before evaluating a prototypical or non-prototypical leadership candidate who was incumbent or prospective. For incumbent candidates, prototypicality predicted more favorable evaluations under low self-uncertainty, but this relationship was weakened under high self-uncertainty. For prospective candidates, prototypicality predicted more favorable evaluations under high self-uncertainty, but this relationship was weakened under low self-uncertainty.

To Lead, or to Follow? How Self-Uncertainty and the Dark Triad of Personality Influence Leadership Motivation.

Under uncertainty, leaders who possess dark triad personality traits seem able to attain leadership positions. We draw on uncertainty-identity theory and dark triad research to explore the effect of self-uncertainty on leadership motivation. Uncertainty-identity theory predicts that people can reduce self-uncertainty by identifying with groups and following their leaders, which suggests that self-uncertainty reduces people's own leadership motivation. However, individuals high in dark triad traits (Machiavellianism, narcissism, and psychopathy) have such a powerful drive for dominance over others that their leadership motivation may be unaffected by self-uncertainty. To test these predictions, we conducted four studies (Ns = 2,641, 421, 513, and 400). We found that self-uncertainty reduced leadership motivation for individuals low in the dark triad. In contrast, those high in the dark triad had an elevated leadership motivation that remained unaltered when they were self-uncertain. These effects were mediated by participants' negative affect. We discuss the implications of these findings.

Psychological Science in the Wake of COVID-19: Social, Methodological, and Metascientific Considerations.

The COVID-19 pandemic has extensively changed the state of psychological science from what research questions psychologists can ask to which methodologies psychologists can use to investigate them. In this article, we offer a perspective on how to optimize new research in the pandemic's wake. Because this pandemic is inherently a social phenomenon-an event that hinges on human-to-human contact-we focus on socially relevant subfields of psychology. We highlight specific psychological phenomena that have likely shifted as a result of the pandemic and discuss theoretical, methodological, and practical considerations of conducting research on these phenomena. After this discussion, we evaluate metascientific issues that have been amplified by the pandemic. We aim to demonstrate how theoretically grounded views on the COVID-19 pandemic can help make psychological science stronger-not weaker-in its wake.

Battling ingroup bias with effective intergroup leadership.

Intergroup conflict and bias often occur between subgroups nested within a superordinate group. In these situations, the leader of the superordinate group plays a key role, as an intergroup leader, in reducing conflict. To be effective, an intergroup leader should avoid (1) threatening the subgroups' distinctive identities, and (2) being viewed by one or both groups as 'one of them' rather than 'one of us'. Intergroup leadership theory (Acad Manag Rev, 37, 2012a, 232) posits intergroup leaders can improve subgroup relations by promoting an intergroup relational identity. Two studies (Ns = 178 and 223) tested whether an out-subgroup or in-subgroup leader could improve intergroup attitudes, even among strong subgroup identifiers, by promoting either an intergroup relational identity or a collective identity. We hypothesized an interaction of these variables demonstrating the effectiveness of an intergroup relational identity message for an out-subgroup leader in lessening ingroup bias, especially among strong subgroup identification. Our results, and a meta-analytic summary across both studies (N = 401), supported our hypothesis and intergroup leadership theory, demonstrating an intergroup relational identity is an effective strategy for improving intergroup relations.

Risk factors for genital infections in people initiating SGLT2 inhibitors and their impact on discontinuation.

INTRODUCTION: To identify risk factors, absolute risk, and impact on treatment discontinuation of genital infections with sodium-glucose co-transporter-2 inhibitors (SGLT2i). RESEARCH DESIGN AND METHODS: We assessed the relationship between baseline characteristics and genital infection in 21 004 people with type 2 diabetes initiating SGLT2i and 55 471 controls initiating dipeptidyl peptidase-4 inhibitors (DPP4i) in a UK primary care database. We assessed absolute risk of infection in those with key risk factors and the association between early genital infection and treatment discontinuation. RESULTS: Genital infection was substantially more common in those treated with SGLT2i (8.1% within 1 year) than DPP4i (1.8%). Key predictors of infection with SGLT2i were female sex (HR 3.64; 95% CI 3.23 to 4.11) and history of genital infection; <1 year before initiation (HR 4.38; 3.73 to 5.13), 1-5 years (HR 3.04; 2.64 to 3.51), and >5 years (HR 1.79; 1.55 to 2.07). Baseline HbA1c was not associated with infection risk for SGLT2i, in contrast to DPP4i where risk increased with higher HbA1c. One-year absolute risk of genital infection with SGLT2i was highest for those with a history of prior infection (females 23.7%, males 12.1%), compared with those without (females 10.8%, males 2.7%). Early genital infection was associated with a similar discontinuation risk for SGLT2i (HR 1.48; 1.21-1.80) and DPP4i (HR 1.58; 1.21-2.07). CONCLUSIONS: Female sex and history of prior infection are simple features that can identify subgroups at greatly increased risk of genital infections with SGLT2i therapy. These data can be used to risk-stratify patients. High HbA1c is not a risk factor for genital infections with SGLT2i.

Intergroup Leadership Across Distinct Subgroups and Identities.

Resolving intergroup conflict is a significant and often arduous leadership challenge, yet existing theory and research rarely, if ever, discuss or examine this situation. Leaders confront a significant challenge when they provide leadership across deep divisions between distinct subgroups defined by self-contained identities-The challenge is to avoid provoking subgroup identity distinctiveness threat. Drawing on intergroup leadership theory, three studies were conducted to test the core hypothesis that, where identity threat exists, leaders promoting an intergroup relational identity will be better evaluated and are more effective than leaders promoting a collective identity; in the absence of threat, leaders promoting a collective identity will prevail. Studies 1 and 2 ( N = 170; N = 120) supported this general proposition. Study 3 ( N = 136) extended these findings, showing that leaders promoting an intergroup relational identity, but not a collective identity, improved intergroup attitudes when participants experienced an identity distinctiveness threat.

Social identities and shared realities.

People are fundamentally motivated to establish a shared reality with others to validate their identity and experiences. Guided by social identity theory, we examine how social identity processes, such as self-categorization and depersonalization, create a shared identity and a sense of shared reality. Research demonstrates that internal states such as attitudes, feelings, and emotions are often shared among members of a group. Furthermore, research has shown that self-uncertainty motivates people to establish shared realities through group identification, often with highly entitative groups that are associated with a self-saturating reality that is shared absolutely. Finally, we review research on how group-defining norms that serve as the bases of these identity-related shared realities are constructed and communicated through group-membership based influence.

Modification of the Grood and Suntay Joint Coordinate System equations for knee joint flexion.

Since its introduction, the Grood and Suntay Joint Coordinate System (JCS) has been embraced by the International Society of Biomechanics (ISB) and been widely used for biomechanical reporting. There is, however, a limitation in its ability to provide correct flexion values over a wide range of clinically relevant flexion angles. This technical note addresses the limitation of the JCS equations and introduces a new set of equations to overcome this problem.

Determination of oral mucosal Poisson's ratio and coefficient of friction from in-vivo contact pressure measurements.

Despite their considerable importance to biomechanics, there are no existing methods available to directly measure apparent Poisson's ratio and friction coefficient of oral mucosa. This study aimed to develop an inverse procedure to determine these two biomechanical parameters by utilizing in vivo experiment of contact pressure between partial denture and beneath mucosa through nonlinear finite element (FE) analysis and surrogate response surface (RS) modelling technique. First, the in vivo denture-mucosa contact pressure was measured by a tactile electronic sensing sheet. Second, a 3D FE model was constructed based on the patient CT images. Third, a range of apparent Poisson's ratios and the coefficients of friction from literature was considered as the design variables in a series of FE runs for constructing a RS surrogate model. Finally, the discrepancy between computed in silico and measured in vivo results was minimized to identify the best matching Poisson's ratio and coefficient of friction. The established non-invasive methodology was demonstrated effective to identify such biomechanical parameters of oral mucosa and can be potentially used for determining the biomaterial properties of other soft biological tissues.

Group members differ in relative prototypicality: Effects on the individual and the group.

All groups are differentiated into more or less group-prototypical members. Central members readily influence and lead the group, and they define its identity. Peripheral members can feel voiceless and marginalized, as well as uncertain about their membership status - they may engage in extreme behaviors to try to win acceptance. These relative prototypicality dynamics sometimes benefit group performance but sometimes compromise performance.

Comparison of isometric and anatomical graft placement in synthetic ACL reconstructions: a pilot study.

Correct graft placement is critical to the success of anterior cruciate ligament reconstructions (ACLR). Whilst current trend is to insert the graft in an anatomical location, synthetic grafts have shown to better perform when they are located in an isometric position. Placement, however, is largely dependent on the surgeon and no consensus has been reached for synthetic grafts. Kinematic flexion-extension data of four separate cadaveric knees was obtained using an optical tracking system. Knees were CT-scanned and computer models were developed for each specimen. Three different graft insertion techniques were simulated in each of the computer models. Kinematic data obtained from the optical tracking was applied to the 3D computer models to simulate knee flexion-extension, and virtual change in ACL graft length was measured over the cycle for each insertion technique. Length changes were plotted onto the Radiological-Quadrant. The isometric region on the femur was found to be a band spreading from the mid to deep end of the Blumensaat's line down to the shallow-inferior end of the femoral condyle. The JP Laboureau isometric point technique was consistently located in the isometric zone, with the following coordinates on the Radiographic-Quadrant: t=0.375 (SD 0.0066), h=0.227 (SD 0.0266). The Bernard-Hertel and Charlie Brown anatomical placement methods were located (13%, -6%) and (8%, -15%) away, from the JP Laboureau isometric point, respectively, based on t- and h- coordinates of the Radiographic-Quadrant. This study has determined the isometric region using three-dimensional analysis relative to the Radiographic-Quadrant. The JP Laboureau method best finds the isometric point. This information is useful for synthetic graft placement.

High-throughput transfection of interfering RNA into a 3D cell-culture chip.

A method for high-throughput retroviral transfection of genes and interfering RNA into 3D cell-culture microarrays is described. 3D cultures more closely mimic the in vivo cellular milieu, thus providing cellular responses to genetic manipulation more similar to the in vivo situation than 2D cultures. This technique is applied to transfect several "toxic" short-hairpin RNAs (shRNAs) into 3D cell cultures. It is demonstrated that the toxicity is similar to that obtained by conventional (non-high-throughput) retroviral transfection of cells grown in similar 3D culture microarrays.

Mechanical variables affecting balloon kyphoplasty outcome--a finite element study.

It is still unclear how a vertebral fracture should be stabilised and strengthened without endangering the remaining intact bone of the augmented vertebra or the adjacent vertebrae. Numerical modelling may provide insight. To date, however, few finite element (FE) spine models have been developed which are both multi-segmental and capture a more complete anatomy of the vertebrae. A 3-D, two-functional unit, CT-based, lumbar spine, FE model was developed and used to predict load transfer and likelihood of fracture following balloon kyphoplasty. The fractured anterior wall and injected cement were modelled in a two-functional spinal unit model with osteoporotic bone properties. Parameters investigated included: cement stiffness, cement volume and height restoration. Models were assessed based on stresses and a user-defined fracture-predicting field. Augmentation altered the stress distribution; shielding was dependent on positioning of the cement; and fracture algorithm found incomplete height restoration to increase the likelihood of fracture, particularly in adjacent vertebrae.

Gene delivery in three-dimensional cell cultures by superparamagnetic nanoparticles.

Three-dimensional (3D) cellular assays closely mimic the in vivo milieu, providing a rapid, inexpensive system for screening drug candidates for toxicity or efficacy in the early stages of drug discovery. However, 3D culture systems may suffer from mass transfer limitations, particularly in delivery of large polypeptide or nucleic acid compounds. Nucleic acids (e.g., genes, silencing RNA) are of particular interest both as potential therapeutics and due to a desire to modulate the gene-expression patterns of cells exposed to small-molecule pharmacological agents. In the present study, polyethylenimine (PEI)-coated superparamagnetic nanoparticles (SPMNs) were designed to deliver interfering RNA and green fluorescent protein (GFP) plasmids through a collagen-gel matrix into 3D cell cultures driven by an external magnetic field. The highest transfection efficiency achieved was 64% for siRNA and 77% for GFP plasmids. Delivery of an shRNA plasmid against GFP by PEI-coated SPMNs silenced the GFP expression with 82% efficiency. We further demonstrated that this delivery approach could be used for screening interfering RNA constructs for therapeutic or toxic effects for cells grown in 3D cultures. Four known toxic shRNA plasmids were delivered by PEI-coated SPMNs into 3D cell cultures, and significant toxicities (41-51% cell death) were obtained.

Religion in the face of uncertainty: an uncertainty-identity theory account of religiousness.

The authors characterize religions as social groups and religiosity as the extent to which a person identifies with a religion, subscribes to its ideology or worldview, and conforms to its normative practices. They argue that religions have attributes that make them well suited to reduce feelings of self-uncertainty. According to uncertainty-identity theory, people are motivated to reduce feelings of uncertainty about or reflecting on self; and identification with groups, particularly highly entitative groups, is a very effective way to reduce uncertainty. All groups provide belief systems and normative prescriptions related to everyday life. However, religions also address the nature of existence, invoking sacred entities and associated rituals and ceremonies. They are entitative groups that provide a moral compass and rules for living that pervade a person's life, making them particularly attractive in times of uncertainty. The authors document data supporting their analysis and discuss conditions that transform religiosity into religious zealotry and extremism.

Three-dimensional cellular microarray for high-throughput toxicology assays.

We have developed a miniaturized 3D cell-culture array (the Data Analysis Toxicology Assay Chip or DataChip) for high-throughput toxicity screening of drug candidates and their cytochrome P450-generated metabolites. The DataChip consists of human cells encapsulated in collagen or alginate gels (as small as 20 nl) arrayed on a functionalized glass slide for spatially addressable screening against multiple compounds. A single DataChip containing 1,080 individual cell cultures, used in conjunction with the complementary human P450-containing microarray (the Metabolizing Enzyme Toxicology Assay Chip or MetaChip), simultaneously provided IC(50) values for nine compounds and their metabolites from CYP1A2, CYP2D6, and CYP3A4 and a mixture of the three P450s designed to emulate the human liver. Similar responses were obtained with the DataChip and conventional 96-well plate assays, demonstrating that the near 2,000-fold miniaturization does not influence the cytotoxicity response. The DataChip may therefore enable toxicity analyses of drug candidates and their metabolites at throughputs compatible with the availability of compounds at early-stage drug discovery.

Integrating social identity theory and the theory of planned behaviour to explain decisions to engage in sustainable agricultural practices.

The present research integrates core aspects of social identity theory with the theory of planned behaviour to investigate factors influencing engagement in sustainable agricultural practices. Using a two-wave prospective design, two studies were conducted with samples of farmers (N = 609 and N = 259, respectively). At Time 1, a questionnaire survey assessed theory of planned behaviour variables in relation to engaging in riparian zone management (a sustainable agricultural practice). In addition, intergroup perceptions (i.e. relations between rural and urban groups), group norms and group identification were assessed. At Time 2, self-reported behaviour was measured. There was support for the integrated model across both studies. As predicted, past behaviour, attitudes and perceived behavioural control were significant predictors of intentions, and intentions significantly predicted self-reported behaviour. Group norms and intergroup perceptions were also significant predictors of intentions providing support for the inclusion of social identity concepts in the theory of planned behaviour. More supportive group norms were associated with higher intentions, especially for high-group identifiers. In contrast, more negative intergroup perceptions were associated with lower intentions and, unexpectedly, this effect only emerged for low-group identifiers. This suggests that in the context of decisions to engage in riparian zone management, an important sustainable agricultural practice, high identifiers are influenced predominantly by in-group rather than out-group considerations, whereas low identifiers may attend to cues from both the in-group and the out-group when making their decisions.

Uncertainty and the influence of group norms in the attitude-behaviour relationship.

Two studies were conducted to examine the impact of subjective uncertainty on conformity to group norms in the attitude-behaviour context. In both studies, subjective uncertainty was manipulated using a deliberative mindset manipulation (McGregor, Zanna, Holmes, & Spencer, 2001). In Study 1 (N=106), participants were exposed to either an attitude-congruent or an attitude-incongruent in-group norm. In Study 2 (N=83), participants were exposed to either a congruent, incongruent, or an ambiguous in-group norm. Ranges of attitude-behaviour outcomes, including attitude-intention consistency and change in attitude-certainty, were assessed. In both studies, levels of group-normative behaviour varied as a function of uncertainty condition. In Study 1, conformity to group norms, as evidenced by variations in the level of attitude-intention consistency, was observed only in the high uncertainty condition. In Study 2, exposure to an ambiguous norm had different effects for those in the low and the high uncertainty conditions. In the low uncertainty condition, greatest conformity was observed in the attitude-congruent norm condition compared with an attitude-congruent or ambiguous norm. In contrast, individuals in the high uncertainty condition displayed greatest conformity when exposed to either an attitude-congruent or an ambiguous in-group norm. The implications of these results for the role of subjective uncertainty in social influence processes are discussed.

Group member prototypicality and intergroup negotiation: how one's standing in the group affects negotiation behaviour.

How does a representative's position in the group influence behaviour in intergroup negotiation? Applying insights from the social identity approach (specifically self-categorization theory), the effects of group member prototypicality, accountability and group attractiveness on competitiveness in intergroup bargaining were examined. As representatives of their group, participants engaged in a computer-mediated negotiation with a simulated out-group opponent. In Experiment 1 (N=114), representatives with a peripheral status in the group sent more competitive and fewer cooperative messages to the opponent than did prototypical representatives, but only under accountability. Experiment 2 (N=110) replicated this finding, and showed that, under accountability, peripherals also made higher demands than did prototypicals, but only when group membership was perceived as attractive. Results are discussed in relation to impression management and strategic behaviour.

Adaptive bone remodelling of all polyethylene unicompartmental tibial bearings.

BACKGROUND: Failure of unicompartmental knees is either by progressive osteoarthritis or by failure of the prosthesis. Prosthesis failure can be because of either the actual component itself or its fixation method. Specifically, the tibial component may wear, loosen or subside into the tibial metaphyseal bone. We modelled all polyethylene tibial components and investigated the periprosthetic adaptive remodelling of the bone. METHODS: Computed tomography scans were used to reconstruct the tibial geometry and a 3-D finite element mesh was created. The tibia loading was set at 45% of the gait cycle. The distal end of the tibia set as fixed. Implant orientations were in accordance with the manufacturer specifications. The bone mineral density changes at three regions of interest under the component were measured and plotted. RESULTS: All regions of interest became stable at the 12-month time-point. Predictive bone mineral changes were minimal in both resorption and deposition. Zones 1-3 for the St Georg Sled (Waldermar Link, Hamburg, Germany) presented evidence of stress shielding and a maximum loss of approximately 6% bone mineral density. The Eius (Stryker Orthopaedics, Mahwah, NJ, USA) showed increased loading and caused an increase in bone mineral density for all regions of interests; the maximum being approximately 10%. CONCLUSION: These findings are consistent with the clinical experience of unicompartmental knee replacements, where the changes are small and have little effect on the outcome of the prosthesis. From a mechanical perspective, the results are also consistent when a compliant material is used to distribute loads. They do, however, support the biomechanical theory that a change in geometry influences the loading environment and as a consequence the adaptive response of the bone is also influenced.