Time, momentum, and energy resolved pump-probe tunneling spectroscopy of two-dimensional electron systems

Real-time probing of electrons can uncover intricate relaxation mechanisms and many-body interactions in strongly correlated materials. Here, we introduce time, momentum, and energy resolved pump-probe tunneling spectroscopy (Tr-MERTS). The method allows the injection of electrons at a particular energy and observation of their subsequent decay in energy-momentum space. Using Tr-MERTS, we visualize electronic decay processes, with lifetimes from tens of nanoseconds to tens of microseconds, in Landau levels formed in a GaAs quantum well. Although most observed features agree with simple energy-relaxation, we discovered a splitting in the nonequilibrium energy spectrum in the vicinity of a ferromagnetic state. An exact diagonalization study suggests that the splitting arises from a maximally spin-polarized state with higher energy than a conventional equilibrium skyrmion. Furthermore, we observe time-dependent relaxation of the splitting, which we attribute to single-flipped spins forming skyrmions. These results establish Tr-MERTS as a powerful tool for studying the properties of a 2DES beyond equilibrium.

Impact of the COVID-19 pandemic on a post-mortem CT service for adult non-suspicious death

Due to the COVID-19 pandemic, the post-mortem computed tomography (PMCT) service was expanded from three to seven cases per day to help mortuary services and avoid invasive autopsy. Additional targeted angiography and pulmonary ventilation procedures were stopped and triage rules relaxed to allow more indications to be scanned, including those requiring toxicology. A service evaluation was performed for the first 3-months of the COVID-19 pandemic compared to the equivalent period the previous year to study the impact of these changes. It was found that, despite the increase in deaths regionally, coronial referrals remained about 100 per month, a reduction in referral rate. The number undergoing PMCT rose from 28% to 74% of cases. Turnaround time remained the same. For cases triaged to PMCT, the need for subsequent autopsy increased from 7.9% to 15.8%. No significant changes were seen in diagnosis rates, including cardiac or respiratory. There was an increase in patients with coronary death without severe coronary calcification who underwent autopsy after PMCT. These may have been diagnosed by targeted coronary angiography. Fifty-three cases requiring toxicology/biochemistry had PMCT, with 38 having PMCT only. In 8/11 (72.7%) cases with normal PMCT and toxicology as the key diagnostic test, autopsy was performed prior to results. This suggests the pathology team were reluctant to risk an "unascertained" outcome. This study shows that it is possible to increase PMCT services by widening referral criteria and by limiting the use of enhanced imaging techniques, without significantly changing diagnosis rates of key diseases; however, selectively restarting targeted angiography may help avoid autopsy in some cases.

Physical Activity Message Framing and Ethnicity Before and During COVID-19

People of Black ethnicities are well known to be disproportionately burdened by coronavirus and have poorer health outcomes. Public health messages encouraged physical activity during the pandemic as it is evidenced to positively affect the immune system, however people of Black ethnicities are often reported as failing to achieve the recommended daily amount. Health message framing during COVID-19 specifically in relation to ethnicity and physical activity motivation has yet to be investigated. Two studies examined message frame effect on physical activity motivation prior to and at the onset of the pandemic and how this differed by ethnicity. Gain framed messages were found to positively affect physical activity motivation pre-COVID-19 and during the pandemic fear framed messages were found to positively affect physical activity motivation. Neither of these effects differed by ethnicity. Implications for future physical activity health message framing are discussed.

When Cisgender, Heterosexual Men Feel Attracted to Transgender Women: Sexuality-Norm Violations Lead to Compensatory Anti-Gay Prejudice

Cisgender, heterosexual men's adherence to gender norms and prejudice against sexual minorities increases after observing sexuality-based gender norm violations of others (i.e., non-normative sexual attractions). No research to date has investigated whether similar effects occur after experiencing sexuality-based gender norm violations of the self. This study investigated the effects of one such norm violation-attraction to transgender women-on adherence to gender roles and attitudes toward gay men. Photographs of female models were shown to cisgender, heterosexual men (N = 135, M age ± S.D. = 28.12 ± 8.81) who rated their attractiveness. Half the participants were informed (accurately) that the models were transgender women (transgender condition). Other participants were not offered this information, leaving them to assume the models were cisgender. All participants then reported their support for traditional gender norms and attitudes toward gay men. As expected, participants in the transgender condition reported less positive attitudes toward gay men, an effect mediated by increased support for traditional gender norms, and only present when the participants had rated the women as highly attractive. These results suggest a strategy to compensate for gender norm violations to reestablish men's masculinity.

Collective Excitations of Exciton-Polariton Condensates in a Synthetic Gauge Field

Collective (elementary) excitations of quantum bosonic condensates, including condensates of exciton polaritons in semiconductor microcavities, are a sensitive probe of interparticle interactions. In anisotropic microcavities with momentum-dependent transverse-electric-transverse-magnetic splitting of the optical modes, the excitations' dispersions are predicted to be strongly anisotropic, which is a consequence of the synthetic magnetic gauge field of the cavity, as well as the interplay between different interaction strengths for polaritons in the singlet and triplet spin configurations. Here, by directly measuring the dispersion of the collective excitations in a high-density optically trapped exciton-polariton condensate, we observe excellent agreement with the theoretical predictions for spinor polariton excitations. We extract the interaction constants for polaritons of the same and opposite spin and map out the characteristic spin textures in an interacting spinor condensate of exciton polaritons.

I Feel Better Naked: Communal Naked Activity Increases Body Appreciation by Reducing Social Physique Anxiety

Positive body image predicts several measures of happiness, well-being, and sexual functioning. Prior research has suggested a link between communal naked activity and positive body image, but has thus far not clarified either the direction or mechanisms of this relationship. This was the first randomized controlled trial of the effects of nakedness on body image. Two potential explanatory mediators of this effect were also investigated. Fifty-one participants were randomly assigned to one of two groups in which they interacted with other people either naked (naked condition) or clothed (control condition). All participants completed measures of body appreciation before and after the intervention, as well as measures of the relative perceived attractiveness of others and social physique anxiety immediately after the intervention. Perceived attractiveness of others was neither affected by the manipulation nor correlated with body appreciation. However, as expected, participants in the naked condition reported more body appreciation, an effect that was mediated by reductions in social physique anxiety. This research provides initial evidence that naked activity can lead to improvements in body image and evidence of a specific explanatory mechanism. Theoretical and practical implications are discussed.

Open to Contact? Increased State Openness Can Lead to Greater Interest in Contact With Diverse Groups

Contact is a reliable method of prejudice reduction. However, individuals higher in prejudice are less interested in contact with diverse groups. This research investigates a novel method of encouraging interest in contact, particularly for those lower in the personality trait of Openness/Intellect, who tend to be higher in prejudice. Although long-term traits are relatively stable, momentary personality states show considerable within-person variation, and can be manipulated. In two experimental studies (total N = 687), we tested whether inducing higher state Openness would affect interest in contact. In Study 1, those lower in trait Openness/Intellect showed a positive indirect effect of condition on two outcome measures, via greater state Openness. In a larger sample with lower trait Openness/Intellect (Study 2), the indirect effect on the first outcome was replicated, regardless of disposition. The findings suggest that experiencing open states more frequently could encourage contact and lead to eventual reductions in prejudice.

Implicit racism, colour blindness, and narrow definitions of discrimination: Why some White people prefer 'All Lives Matter' to 'Black Lives Matter'

The Black Lives Matter (BLM) movement has been called the 'civil rights issue of our time' (Holt & Sweitzer, 2020, Self and Identity, 19(, p. 16) but the All Lives Matter (ALM) movement swiftly emerged as an oppositional response to BLM. Prior research has investigated some predictors of support for ALM over BLM, but these predictors have thus far not included levels of racial bias or potentially relevant constructions of racism. This pre-registered, cross-sectional study (N = 287) tested the degree to which White participants' support for ALM could be predicted using measures of racism (implicit and explicit) and ideological stances around the construction of 'racism' (that discourage the recognition of contemporary inequalities and discrimination). Using multiple regression analyses, we found that implicit racism, colour-blind ideology, and narrow definitional boundaries of discrimination positively predicted support for ALM over BLM. Explicit racism, collective narcissism, and right-wing political orientation did not predict ALM support, nor did any (2-way) interaction of these predictors. Implications for our understanding of the All Lives Matter movement are discussed.

Fragile Heterosexuality

Abstract. Previous research demonstrates that membership of majority groups is often perceived as more fragile than membership of minority groups. Four studies ( N1 = 90, N2 = 247, N3 = 500, N4 = 1,176) investigated whether this was the case for heterosexual identity, relative to gay identity. Support for fragile heterosexuality was found using various methods: sexual orientation perceptions of a target who engaged in incongruent behavior, free-responses concerning behaviors required to change someone’s mind about a target’s sexual orientation, agreement with statements about men/women’s sexual orientation, and agreement with gender-neutral statements about sexual orientation. Neither participant nor target gender eliminated or reversed this effect. Additionally, we investigated multiple explanations (moderators) of the perceived difference in fragility between heterosexual identity and gay identity and found that higher estimates of the gay/lesbian population decreased the difference between the (higher) perceived fragility of heterosexual identity and the (lower) perceived fragility of gay identity.

Enhancement of Parametric Effects in Polariton Waveguides Induced by Dipolar Interactions

Exciton-polaritons are hybrid light-matter excitations arising from the nonperturbative coupling of a photonic mode and an excitonic resonance. Behaving as interacting photons, they show optical third-order nonlinearities providing effects such as optical parametric oscillation or amplification. It has been suggested that polariton-polariton interactions can be greatly enhanced by inducing aligned electric dipoles in their excitonic part. However, direct evidence of a true particle-particle interaction, such as superfluidity or parametric scattering, is still missing. In this Letter, we demonstrate that dipolar interactions can be used to enhance parametric effects such as self-phase modulation in waveguide polaritons. By quantifying these optical nonlinearities, we provide a reliable experimental measurement of the direct dipolar enhancement of polariton-polariton interactions.

Extensive mucocutaneous, oesophageal and otic lichen planus secondary to nivolumab therapy

We report a 73-year-old female with metastatic renal cell carcinoma who developed a widespread lichenoid reaction following nivolumab treatment. The timeline of the reaction strongly correlated with the nivolumab treatment and subsequent cessation. Our patient had cutaneous, mucosal, otic, ophthalmic and oesophageal involvement, demonstrating the potentially extensive nature of lichenoid reactions to anti-programmed cell death receptor-1 (anti-PD1) therapies. Although lichenoid reactions to anti-PD1 therapies are now well recognized, there have been no previous reports of otic or oesophageal involvement in the literature. Although cutaneous lichenoid reactions do not tend to be severe or treatment limiting, more widespread systemic lichenoid reactions are challenging to manage, particularly in the context of malignancy. This very unusual case highlights the importance of considering involvement beyond the skin in all lichenoid skin reactions.

Low-Energy Collective Oscillations and Bogoliubov Sound in an Exciton-Polariton Condensate

We report the observation of low-energy, low-momenta collective oscillations of an exciton-polariton condensate in a round "box" trap. The oscillations are dominated by the dipole and breathing modes, and the ratio of the frequencies of the two modes is consistent with that of a weakly interacting two-dimensional trapped Bose gas. The speed of sound extracted from the dipole oscillation frequency is smaller than the Bogoliubov sound, which can be partly explained by the influence of the incoherent reservoir. These results pave the way for understanding the effects of reservoir, dissipation, energy relaxation, and finite temperature on the superfluid properties of exciton-polariton condensates and other two-dimensional open-dissipative quantum fluids.

Reflecting on nostalgic, positive, and novel experiences increases state Openness

OBJECTIVE

Personality change is a growing field of interest, but relatively few studies have examined causes of change in Openness. We investigated whether it is possible to influence state Openness, and through what mechanisms this effect may occur.

METHOD

In two experiments (Study 1: N = 144, M_age  = 36.4, 58% female, 88% White; Study 2: N = 269, M_age  = 34.0, 60% female, 91% White), participants reflected on and wrote about a personal experience requested to be either: nostalgic; positive and novel (Study 1); positive or novel (Study 2); or ordinary. They rated the events for nostalgia, positivity, novelty, and sociality, and completed measures of state positive affect, self-esteem, social connectedness, meaning in life, and state Openness.

RESULTS

Participants who recalled positive and/or novel events reported greater state Openness than those who recalled ordinary events. In Study 1, this also applied to those recalling nostalgic events. Event ratings of positivity (both studies), nostalgia and novelty (Study 2) independently predicted state Openness. State positive affect and self-esteem were independent predictors in both studies, suggesting possible indirect paths.

CONCLUSIONS

Reflecting on nostalgic, positive, and novel experiences can increase state Openness. This finding may be useful for interventions targeting trait-level change.

Interethnic Bias in Willingness to Engage in Casual Sex Versus Committed Relationships

Interethnic romantic relationships are widely seen as a strong indicator of a well-integrated society. However, racial bias may still be evident in the tendency to engage in casual sex versus committed relationships. Using a large, age-diverse sample of 3,453 White British participants, this study found a general preference for White partners over racial minority partners. Furthermore, in line with social structural theory, participants reported a relative preference for marriage (versus casual sex) with White partners, but a relative preference for casual sex (versus marriage) with racial minorities. This pattern was further modified by sex: Men reported a general preference for casual sex (versus marriage) with all racial groups except White partners. Women, however, reported a general preference for marriage (versus casual sex) with all groups, but this preference was strongest for White partners. The pattern was not further modified by sexual orientation. Implications for contemporary interethnic romantic relationships are discussed.

Brexit: The influence of motivation to respond without prejudice, willingness to disagree, and attitudes to immigration

Britain's unexpected vote to leave the European Union (Brexit) in June 2016 has proved divisive and damaging both within the United Kingdom and internationally. Across two correlational studies, the current research proposed a model to explain the Brexit vote, with attitudes to immigration and willingness to disagree (WD) as direct predictors of the referendum result, and internal (IMS) and external (EMS) motivation to respond without prejudice as indirect predictors. Study 1 (N = 353) and Study 2 (N = 363) both showed good fit with the model and, respectively, explained 48% and 46% of the referendum result. More positive attitudes to immigration predicted a vote to remain. Higher IMS and lower EMS predicted a vote to remain, fully mediated by attitudes to immigration. In Study 1, lower WD also predicted a vote to remain, both directly and indirectly via attitudes to immigration, although this was not replicated in Study 2. These results are discussed both in relation to the Brexit result, and the implications for motivation to respond without prejudice, WD, and political correctness more generally.

Gendered Perceptions of Sexual Abuse: Investigating the Effect of Offender, Victim and Observer Gender on the Perceived Seriousness of Child Sexual Abuse

Sexual abuse of children is a pervasive, global issue. Perpetrators of this kind of abuse are often stereotyped as male, meaning that research comparing perceptions of abuse by male versus female offenders is limited. This is an important omission as recent evidence attests to the unexpectedly high frequency of sexual crimes perpetrated by women. The gender of child sex abuse victims and observers of abuse have also been shown to impact perceptions of the offense. Thus, the present study aimed to explore the effect of offender, victim and observer gender on the perceived seriousness of an act of child sex abuse. To do this, we used a 2 (offender gender: male vs female) × 2 (victim gender: male vs female) × 2 (observer gender: male vs female) between-participants experimental design. We presented members of the British public (N = 213) with a vignette describing a hypothetical interaction between an offender and victim and asked them how serious they thought the offense was. They then reported their own gender. We found that abuse was considered more serious when the offender was male, or the observer was female. We also found a novel three-way interaction. Implications and future research directions are discussed.

Acoustoelectric Study of Microwave-Induced Current Domains

Surface acoustic waves (SAW) have been utilized to investigate the properties of a two-dimensional electron system subjected to a perpendicular magnetic field and monochromatic microwave radiation in the regime where the so-called microwave-induced zero-resistance states form. Contrary to conventional magnetotransport in Hall bar and van der Pauw geometries, the collimated SAW beam probes only the bulk of the electronic system exposed to this wave. Clear signatures appear in the SAW propagation velocity, corroborating that neither contacts nor sample edges are a root source for their emergence. By virtue of the directional nature of this probing method and with the assistance of theoretical modeling, we were able to demonstrate that the SAW response depends on the angle between its propagation vector and the orientation of domains that spontaneously form when zero-resistance is observed in transport. This confirms in unprecedented manner the formation of an inhomogeneous phase under these nonequilibrium conditions.

Painting all foreigners with one brush? How the salience of muslims and refugees shapes judgements

Attitudes towards foreigners are widely researched, most frequently in survey studies. However, in that context it is often unclear which attitude object respondents have in mind, and thus what their answers refer to. This paper uses a representative sample of 3,195 Germans who reported which groups they think of when thinking about foreigners living in Germany. We found that Germans disproportionately think of groups who are Muslim, and that such salience is associated with more negative attitudes towards “foreigners.” This holds true when controlling for attitudes towards Muslims; in fact, thinking of Muslim groups when thinking about foreigners moderates the relationship between anti-Muslim and anti-foreigner attitudes. The relationships were weaker when respondents think of Turks, a large and long-standing minority in Germany, suggesting an attenuation of the links through familiarity or intergroup contacts. No relationship was found between thinking of refugees and attitudes towards foreigners. Implications for research are discussed, particularly regarding the interpretation of self-reported attitudes towards foreigners and the study of populist strategies.

Testing Hypersensitive Responses: Ethnic Minorities Are Not More Sensitive to Microaggressions, They Just Experience Them More Frequently

Racial microaggressions have attracted significant empirical attention and have been associated with profound negative effects. However, some argue against the importance of microaggressions arguing that (some) responses to microaggressions merely reflect “hypersensitivity” to trivial events among certain ethnic minority individuals. Three studies tested this hypersensitivity hypothesis. In two cross-sectional studies with dissimilar samples ( N1 = 130, N2 = 264), ethnic minorities reported experiencing more microaggressions than ethnic majorities did, and microaggressions predicted less life satisfaction. However, contrary to the hypersensitivity hypothesis, minority identity did not moderate this relationship. In a randomized, controlled experiment ( N3 = 114), White and ethnic minority participants reported their positive and negative affect before and after recalling either a microaggression or a control event. Recalling microaggressions reduced positive affect and increased negative affect, but this was also not moderated by minority identity. Implications for the hypersensitivity hypothesis, and microaggressions research, are discussed.

Does Contact Matter?: The Relative Importance of Contact in Predicting Anti-Gay Prejudice in Jamaica

Jamaica has been called one of the world's most anti-gay countries. However, little empirical research has investigated methods of reducing this prejudice. Intergroup contact-(positive) interaction with someone from a different social group-is one of the most widely tested and strongly favored methods of reducing prejudice. However, the role of contact in this specific context is not clear, particularly the relative importance of contact compared to other variables that predict (less) prejudice. This current cross-sectional research investigated that question using a large, representative sample of Jamaican participants (N = 942). As in prior research, contact predicted less anti-gay prejudice, and the (negative) relationship between contact and anti-gay behaviors was mediated by intergroup anxiety and attitudes, even when other important predictors were taken into account. However, contact was a less important predictor than gender, education, or religiosity. Implications for intergroup contact and prejudice-reduction strategies in Jamaica are discussed.

Understanding and Reducing Sexual Prejudice in Jamaica: Theoretical and Practical Insights From a Severely Anti-Gay Society

Jamaica has earned an international reputation for severe sexual prejudice-perhaps disproportionately so compared to other severely anti-LGBT (lesbian, gay, bisexual, and transgender) societies. Until recently, however, no quantitative empirical research had investigated Jamaica's sexual prejudice, leaving the prejudice poorly understood and methods of reducing it unclear. This article reviews empirical research on Jamaican anti-LGBT prejudice from the past 15 years. It situates Jamaica within the global context, explains the current understanding of the severity and nature of the problem, evaluates solutions currently being explored, and suggests promising strategies based on available evidence. Importantly, this article also reflects on lessons learned from Jamaica that are relevant for other severely anti-LGBT societies.

Chiral Modes at Exceptional Points in Exciton-Polariton Quantum Fluids

We demonstrate the generation of chiral modes-vortex flows with fixed handedness in exciton-polariton quantum fluids. The chiral modes arise in the vicinity of exceptional points (non-Hermitian spectral degeneracies) in an optically induced resonator for exciton polaritons. In particular, a vortex is generated by driving two dipole modes of the non-Hermitian ring resonator into degeneracy. Transition through the exceptional point in the space of the system's parameters is enabled by precise manipulation of real and imaginary parts of the closed-wall potential forming the resonator. As the system is driven to the vicinity of the exceptional point, we observe the formation of a vortex state with a fixed orbital angular momentum (topological charge). This method can be extended to generate higher-order orbital angular momentum states through coalescence of multiple non-Hermitian spectral degeneracies. Our Letter demonstrates the possibility of exploiting nontrivial and counterintuitive properties of waves near exceptional points in macroscopic quantum systems.

The colored Hanbury Brown-Twiss effect

The Hanbury Brown-Twiss effect is one of the celebrated phenomenologies of modern physics that accommodates equally well classical (interferences of waves) and quantum (correlations between indistinguishable particles) interpretations. The effect was discovered in the late thirties with a basic observation of Hanbury Brown that radio-pulses from two distinct antennas generate signals on the oscilloscope that wiggle similarly to the naked eye. When Hanbury Brown and his mathematician colleague Twiss took the obvious step to propose bringing the effect in the optical range, they met with considerable opposition as single-photon interferences were deemed impossible. The Hanbury Brown-Twiss effect is nowadays universally accepted and, being so fundamental, embodies many subtleties of our understanding of the wave/particle dual nature of light. Thanks to a novel experimental technique, we report here a generalized version of the Hanbury Brown-Twiss effect to include the frequency of the detected light, or, from the particle point of view, the energy of the detected photons. Our source of light is a polariton condensate, that allows high-resolution filtering of a spectrally broad source with a high degree of coherence. In addition to the known tendencies of indistinguishable photons to arrive together on the detector, we find that photons of different colors present the opposite characteristic of avoiding each others. We postulate that fermions can be similarly brought to exhibit positive (boson-like) correlations by frequency filtering.

Jamaica, Three Years Later: Effects of Intensified Pro-Gay Activism on Severe Prejudice Against Lesbians and Gay Men

Jamaica has developed an international reputation for severe anti-gay prejudice. However, in the past few years, between 2012 and 2015, intensified waves of activism have increased the visibility of lesbian, gay, bisexual, and transgender (LGBT) Jamaicans, and supported their social and legal inclusion in Jamaican society. This research investigated the effects of that activism by taking advantage of two large, representative surveys of Jamaicans' attitudes toward lesbians and gay men: one in 2012 and one in 2015. Over the three-year period there were significant reductions in desire for social distance and opposition to gay rights. However, there was no significant change in anti-gay attitudes, and there was evidence of an increase in anti-gay behaviors. There was also no evidence of polarization of responses to gay men and lesbians; rather, the most prejudiced Jamaicans showed the largest reductions in bias. Implications of these findings for activism in Jamaica and other anti-gay countries are discussed.

Immunohistochemical Evaluation of Mononuclear Infiltrates in Canine Lupoid Onychodystrophy

Claw biopsy samples of 11 dogs with lupoid onychodystrophy were evaluated. They were stained with hematoxylin and eosin and with antibodies against CD 3 as a T-cell marker, BLA 36 and HM 57 (CD 79α) as B-cell markers, and lysozyme, Mac 387, and major histocompatibility complex (MHC) class II as a marker for histiocytes using an immunoperoxidase and avidin-biotin technique. Inflammatory cells were counted in five high-power fields. The inflammatory infiltrate comprised predominantly B cells and T cells. Macrophages were typically only present in small numbers. CD 3, BLA 36, lysozyme, and MHC class II preserved significant antigenicity during formalin fixation and short decalcification for 24–48 hours, whereas CD 79α and particularly Mac 387 seemed to be more susceptible to denaturation by the decalcification process.

An assessment of West African seahorses in fisheries catch and trade

This study provides the first assessment of a heavily traded West African seahorse species, Hippocampus algiricus, and the first information on short-snouted seahorse Hippocampus hippocampus biology in Africa. A total of 219 seahorses were sampled from fisher catch in Senegal and The Gambia, with estimated height at reproductive activity for H. algiricus (161 mm) larger than mean ± S.D. catch height (150 ± 31 mm). Catch composition, height at reproductive activity and potential biases in fishery retention are discussed with regard to the current Convention on International Trade of Endangered Species (CITES) guidelines.