Repetitive patterns in rapid optical variations in the nearby black-hole binary V404 Cygni.

How black holes accrete surrounding matter is a fundamental yet unsolved question in astrophysics. It is generally believed that matter is absorbed into black holes via accretion disks, the state of which depends primarily on the mass-accretion rate. When this rate approaches the critical rate (the Eddington limit), thermal instability is supposed to occur in the inner disk, causing repetitive patterns of large-amplitude X-ray variability (oscillations) on timescales of minutes to hours. In fact, such oscillations have been observed only in sources with a high mass-accretion rate, such as GRS 1915+105 (refs 2, 3). These large-amplitude, relatively slow timescale, phenomena are thought to have physical origins distinct from those of X-ray or optical variations with small amplitudes and fast timescales (less than about 10 seconds) often observed in other black-hole binaries-for example, XTE J1118+480 (ref. 4) and GX 339-4 (ref. 5). Here we report an extensive multi-colour optical photometric data set of V404 Cygni, an X-ray transient source containing a black hole of nine solar masses (and a companion star) at a distance of 2.4 kiloparsecs (ref. 8). Our data show that optical oscillations on timescales of 100 seconds to 2.5 hours can occur at mass-accretion rates more than ten times lower than previously thought. This suggests that the accretion rate is not the critical parameter for inducing inner-disk instabilities. Instead, we propose that a long orbital period is a key condition for these large-amplitude oscillations, because the outer part of the large disk in binaries with long orbital periods will have surface densities too low to maintain sustained mass accretion to the inner part of the disk. The lack of sustained accretion--not the actual rate--would then be the critical factor causing large-amplitude oscillations in long-period systems.

Supporting mentalizing in primary school children: the effects of thoughts in mind project for children (TiM-C) on metacognition, emotion regulation and theory of mind.

Mentalization is a useful ability for social functioning and a crucial aspect of mentalizing is emotion regulation. Literature suggests programmes for children and adults to increase mentalizing abilities useful both for emotional and social competences. For this reason, the issue of how to prompt children's mentalization has started to attract researchers' attention, supporting the importance of the interpersonal dimension for the individual differences in the developmental of mentalization. The TiM (Thoughts in Mind) Project, a training programme based on the explanation of mentalization mechanisms and designed for adults, deals with emotion regulation. Starting from the TiM Project, this study tests the effects of the TiM Child (TiM-C) training programme, over a control training programme, a conversational training designed for the school context, in children attending Year 2 of primary school. We designed a training based on narratives, followed by multiple-choice questions and conversations about mental states. Our results revealed significant improvements over the training period only in the TiM-C Project group for Metacognition, Emotion Regulation Strategies and a Theory of Mind task. As far as the educational implications, our findings suggest that it is possible to enhance mentalization through activities at school by promoting not only the understanding of the relations between mind and emotion, but also metacognitive skills.

Continuous wave vertical emission from terahertz microcavity lasers with a dual injection scheme.

Quantum cascade lasers (QCLs) represent a most promising compact source at terahertz (THz) frequencies, but efficiency of their continuous wave (CW) operation still needs to be improved to achieve large-scale exploitation. Here, we demonstrate highly efficient operation of a subwavelength microcavity laser consisting of two evanescently coupled whispering gallery microdisk resonators. Exploiting a dual injection scheme for the laser cavity, single mode CW vertical emission at 3.3 THz is obtained at 10 K with 6.4 mA threshold current and 145 mW/A slope efficiency up to 320 µW emitted power measured in quasi-CW mode. The tuning of the laser emission directionality is also obtained by independently varying the pumping strength between the microdisks. By connecting the resonators through a suspended gold bridge, the laser out-coupling efficiency in the vertical direction is strongly enhanced. Owing to the high brightness, low-power consumption and CW operation, the proposed microcavity laser design could allow the realization of high-performance CW THz QCLs ready for massive parallelization.

Systemic review and network meta-analysis comparing minimal surgical techniques for rectal cancer: quality of total mesorectum excision, pathological, surgical, and oncological outcomes.

BACKGROUND: Minimal invasive surgery has revolutionized recovery in rectal cancer patients. However, there has been debate on its effect on quality of total mesorectal excision (TME) and oncological outcomes. This network meta-analysis compares laparoscopic, robotic-assisted, and transanal TMEs. This study shows that All three surgical techniques are comparable across TME quality and oncological outcomes. Ultimately, good outcomes are based on each individual surgeon choosing an approach based on their expertise.

Theory of mind plasticity in aging: The role of baseline, verbal knowledge, and executive functions.

Theory of Mind (ToM) refers to the ability to attribute mental states to the self and others in order to explain and predict social behaviour. Meta-analytic results have shown a decline in ToM abilities in healthy older adults. Recent research has also highlighted the possibility of enhancing older adults' ToM performance through group conversations focused on mental states. Our aim was to determine whether the extent to which older people benefited from a ToM training was predicted by performance on a battery of executive functioning tasks, on baselines in ToM tasks, on verbal knowledge. Forty-three older adults (60-84 years) participated in a three-session ToM training programme that has previously shown to be effective in improving ToM ability. Results showed that verbal knowledge predicted training gains in practiced ToM tasks. In addition, age, executive functions and baseline performance predicted training gains in non-practiced ToM tasks. Results are discussed in light of the amplification model.

Symmetry enhanced non-reciprocal polarization rotation in a terahertz metal-graphene metasurface.

In the present article we numerically investigated the magneto-optical behaviour of a sub-wavelength structure composed by a monolayer graphene and a metallic metasurface of optical resonators. Using this hybrid graphene-metal structure, a large increase of the non-reciprocal polarization rotation of graphene can be achieved over a broad range of terahertz frequencies. We demonstrate that the symmetry of the resonator geometry plays a key role for the performance of the system: in particular, increasing the symmetry of the resonator the non-reciprocal properties can be progressively enhanced. Moreover, the possibility to exploit the metallic metasurface as a voltage gate to vary the graphene Fermi energy allows the system working point to be tuned to the desired frequency range. Another peculiar result is the achievement of a structure able to operate both in transmission and reflection with almost the same performance, but in a different frequency range of operation. The described system is hence a sub-wavelength, tunable, multifunctional, effective non-reciprocal element in the terahertz region.

Supernova SN 2011fe from an exploding carbon-oxygen white dwarf star.

Type Ia supernovae have been used empirically as 'standard candles' to demonstrate the acceleration of the expansion of the Universe even though fundamental details, such as the nature of their progenitor systems and how the stars explode, remain a mystery. There is consensus that a white dwarf star explodes after accreting matter in a binary system, but the secondary body could be anything from a main-sequence star to a red giant, or even another white dwarf. This uncertainty stems from the fact that no recent type Ia supernova has been discovered close enough to Earth to detect the stars before explosion. Here we report early observations of supernova SN 2011fe in the galaxy M101 at a distance from Earth of 6.4 megaparsecs. We find that the exploding star was probably a carbon-oxygen white dwarf, and from the lack of an early shock we conclude that the companion was probably a main-sequence star. Early spectroscopy shows high-velocity oxygen that slows rapidly, on a timescale of hours, and extensive mixing of newly synthesized intermediate-mass elements in the outermost layers of the supernova. A companion paper uses pre-explosion images to rule out luminous red giants and most helium stars as companions to the progenitor.

Opposite actions of urotensin II and relaxin-2 on cellular expression of fibronectin in renal fibrosis: A preliminary experimental study.

Our aim was to evaluate the role of urotensin II, urantide (urotensin II receptor antagonist) and relaxin-2 on the cellular expression of fibronectin as a surrogate marker for renal fibrosis. We employed LLC-PK1 renal tubular epithelial cells and assessed the influence on the fibrotic process of the above-mentioned substances by using anti-fibronectin antibodies in western blot analysis. The addition of urotensin II increased fibronectin expression. Urantide reduced the positivity for fibronectin caused by urotensin II (P<.05). The anti-fibrotic action was more evident for relaxin-2 (P<.01). Also in the model of TGF-ß1-induced fibrosis, urantide and, to a greater extent, relaxin-2 were able to significantly lessen fibronectin expression (respectively, P<.05 and P<.01). In conclusion, relaxin-2 may reduce urotensin II-induced renal fibrosis.

Relations between theory of mind and executive function in middle childhood: A short-term longitudinal study.

Studies with preschool children have shown significant links between children's executive function (EF) and theory of mind (ToM), but few studies have examined these associations in primary school children. To address this gap, we designed a three-wave cross-lagged longitudinal study in which we followed a group of 113 children (61 boys) across three time points from age 9.5-10.5years (mean age at Time 1=112.3months, SD=4.18; mean age at Time 2=118.3months, SD=4.15; mean age at Time 3=124.7months, SD=4.06). At each time point, we measured EF (working memory and inhibitory control), ToM, and language. Our analyses showed (a) moderate rank-order stability of individual differences in both EF and ToM and (b) growth in ToM task performance across time. Cross-lagged longitudinal analyses revealed an asymmetric developmental relation between ToM and working memory. Early working memory predicted later ToM but not vice versa. Our results suggest a specific role for working memory in the ongoing development of ToM in middle childhood.

Theory of Mind and social relationships in older adults: the role of social motivation.

OBJECTIVES: Previous research has shown that individual differences in Theory of Mind (ToM) are crucial for people's social relationships. However, very few studies have investigated this issue in ageing. The present study was designed to fill this gap and examine the associations between ToM and social relationships in elderly adults. In doing so, this study considered people's relationships with their relatives and friends, and examined the possible moderating role of social motivation. METHOD: The study involved 53 healthy older adults (age: M = 67.91; SD = 6.93; range: 60--85 years). All participants were tested collectively during a 2-hr session and completed a demographic questionnaire as well as a battery of tests assessing verbal ability (vocabulary and word fluency), ToM and social relationships. They also answered a social motivation question. RESULTS: Results showed that individual differences in older people's ToM were overall significantly associated with those in relationships with friends, but not relatives. In addition, the Hayes moderating procedure showed that individual differences in ToM were related to those in friendships only for those people who had a high or medium level of social motivation. CONCLUSION: These findings underline the importance of motivation in guiding the use of ToM in everyday social interactions.

Saturable absorption of femtosecond optical pulses in multilayer turbostratic graphene.

We investigate the nonlinear transmission of a ~280-layer turbostratic graphene sheet for near-infrared amplifier laser pulses (775 nm, Ti:sapphire laser) with a duration of 150-fs and 20-fs. Saturable absorption is observed in both cases, however it is not very strong, amounting to ~13% transmittance change for the 20-fs (150-fs) pulses at a peak intensity of 30 GW/cm2 (4 GW/cm2). The dependence on incident peak intensity is reproduced well using a theoretical model for the time-dependent saturable absorption, where the excited carriers vacate the photo-excited energy range within 3-5 fs, which we attribute to energy redistribution due to carrier-carrier scattering. This is also supported by spectrally resolved measurements for the 20-fs pulses, which show a marked dependence of the degree of saturation on the photon energy. A key result is that the shorter pulses do not yield a lower saturation fluence, due to the combined effects of the broader excitation bandwidth, and the rapid and broad energy redistribution. We also predict the potential performance of multilayer graphene samples for removing pedestal and pre-pulse structure from ultrafast high-energy pulses.

Conversations about mental states and theory of mind development during middle childhood: A training study.

Despite 30years of productive research on theory of mind (ToM), we still know relatively little about variables that influence ToM development during middle childhood. Recent experimental studies have shown that conversations about the mind affect ToM abilities, but they have not explored the mechanisms underlying this developmental effect. In the current study, we examined two potential mechanisms through which conversations about mental states are likely to influence ToM: an increased frequency of references to mental states when explaining behavior and an increased accuracy of mental-state attributions. To this aim, we conducted a training study in which 101 children were assigned to either an intervention condition or a control condition. The conversation-based intervention was made up of four sessions scheduled over 2weeks. Children completed a battery of assessments before and after the intervention as well as 2months later. The groups were equivalent at Time 1 (T1) for age, family affluence, vocabulary, and executive functions. The ToM group showed an improvement in ToM skills (as evaluated on both the practiced tasks and a transfer task). Mediation analyses demonstrated that the accuracy of mental-state attributions, but not the mere frequency of mental-state references, mediated the positive effect of conversations about the mind on ToM development. Our results indicate that conversational experience can enhance mental-state reasoning not by simply drawing children's attention to mental states but rather by scaffolding a mature understanding of social situations.

Promoting theory of mind in older adults: does age play a role?

OBJECTIVES: Previous research on age-related changes in Theory of Mind (ToM) showed a decline in older adults, particularly pronounced over 75 years of age. Evidence that ToM may be enhanced in healthy aging people has been demonstrated, but no study has focused on the role of age on the effects of ToM training for elderly people. The present study was designed to examine the efficacy of a ToM training on practiced (ToM Strange Stories) and transfer tasks (ToM Animations) in both young and older adults. METHOD: The study involved 127 older adults belonging to two age groups: young-old (Mage = 64.41; SD = 2.49; range: 60-69 years) and old-old (Mage = 75.66; SD = 4.38; range: 70-85 years), randomly assigned to either a ToM group or a control group condition. All participants took part in two 2-hour testing sessions and four 2-hour training sessions. RESULTS: Results showed that both young-old and old-old adults in the ToM group condition improved their ability to reason on complex-mental states significantly more than participants in the control group condition. This positive effect of the training was evident on practiced and transfer ToM tasks. Crucially, age did not moderate the effect of the ToM training. CONCLUSION: These findings demonstrate that young-old and old-old adults equally benefit from the ToM training. Implications for the positive effect of the ToM training in old-old adults are discussed.

THz saturable absorption in turbostratic multilayer graphene on silicon carbide.

We investigated the room-temperature Terahertz (THz) response as saturable absorber of turbostratic multilayer graphene grown on the carbon-face of silicon carbide. By employing an open-aperture z-scan method and a 2.9 THz quantum cascade laser as source, a 10% enhancement of transparency is observed. The saturation intensity is several W/cm2, mostly attributed to the Pauli blocking effect in the intrinsic graphene layers. A visible increase of the modulation depth as a function of the number of graphene sheets was recorded as consequence of the low nonsaturable losses. The latter in turn revealed that crystalline disorder is the main limitation to larger modulations, demonstrating that the THz nonlinear absorption properties of turbostratic graphene can be engineered via a proper control of the crystalline disorder and the layers number.

Training preschoolers on first-order false belief understanding: transfer on advanced ToM skills and metamemory.

This study investigated the relation between theory of mind (ToM) and metamemory knowledge using a training methodology. Sixty-two 4- to 5-year-old children were recruited and randomly assigned to one of two training conditions: A first-order false belief (ToM) and a control condition. Intervention and control groups were equivalent at pretest for age, parents' education, verbal ability, inhibition, and ToM. Results showed that after the intervention children in the ToM group improved in their first-order false belief understanding significantly more than children in the control condition. Crucially, the positive effect of the ToM intervention was stable over 2 months and generalized to more complex ToM tasks and metamemory.

Promoting theory of mind during middle childhood: a training program.

Evidence that conversations about the mind foster improvements in theory of mind (ToM) is growing, but their efficacy in typically developing school-aged children has yet to be demonstrated. To address this gap, we designed a conversation-based training program for 9- and 10-year-olds and measured its effectiveness by pre- and post-test comparisons of performance on age-appropriate ToM tasks for two groups (matched at pre-test for gender, age, socioeconomic background, verbal ability, reading comprehension, executive functions, and ToM) who were assigned to either the intervention condition (n=45) or an active control condition (n=46). The intervention group showed significantly greater gains in ToM than the control group; this contrast was stable over 2 months, and (in a subsample) the improvement in ToM was independent of any changes in executive functions. Implications for the role of conversations about the mind in children's mental state reasoning are discussed.

Corrigendum: Children's representations of the COVID-19 lockdown and pandemic through drawings.

[This corrects the article DOI: 10.3389/fpsyg.2022.960893.].

The promotion of mature theory of mind skills in educational settings: a mini-review.

After formal school entry, theory of mind development encounters a blooming period of growth intertwined with social and academic achievements and challenges. Within this framework, in last years researchers have proposed training programs to foster mature ToM skills, but also, to test causal pathways for the role that ToM development may have in broader cognitive and social outcomes. In the current mini-review we examine which training programs have been developed so far to enhance three key aspects of mature ToM skills: second-order false belief reasoning, the ability to put one's own ToM knowledge into use, and the mentalization of thoughts and emotions. We also illustrate effects of these activities on intra- and inter- personal competence. In its conclusion the paper provides considerations of both first achievements of research in this area and gaps to be addressed in future works.

Engineering Multicolor Radiative Centers in hBN Flakes by Varying the Electron Beam Irradiation Parameters.

Recently, hBN has become an interesting platform for quantum optics due to the peculiar defect-related luminescence properties. In this work, multicolor radiative emissions are engineered and tailored by position-controlled low-energy electron irradiation. Varying the irradiation parameters, such as the electron beam energy and/or area dose, we are able to induce light emissions at different wavelengths in the green-red range. In particular, the 10 keV and 20 keV irradiation levels induce the appearance of broad emission in the orange-red range (600-660 nm), while 15 keV gives rise to a sharp emission in the green range (535 nm). The cumulative dose density increase demonstrates the presence of a threshold value. The overcoming of the threshold, which is different for each electron beam energy level, causes the generation of non-radiative recombination pathways.

Internalizing and externalizing symptoms in children during the COVID-19 pandemic: a systematic mixed studies review.

Introduction: Given the vulnerability of children during the COVID-19 pandemic, paying close attention to their wellbeing at the time is warranted. The present protocol-based systematic mixed-studies review examines papers published during 2020-2022, focusing on the impact of the COVID-19 pandemic on children's internalizing/externalizing symptoms and the determinants thereof. Method: PROSPERO: CRD42022385284. Five databases were searched and the PRISMA diagram was applied. The inclusion criteria were: papers published in English in peer-reviewed journals; papers published between January 2020 and October 2022 involving children aged 5-13 years; qualitative, quantitative, and mixed studies. The standardized Mixed Method Appraisal Tool protocol was used to appraise the quality of the studies. Results: Thirty-four studies involving 40,976 participants in total were analyzed. Their principal characteristics were tabulated. The results showed that children's internalizing/externalizing symptoms increased during the pandemic, largely as a result of disengagement from play activities and excessive use of the internet. Girls showed more internalizing symptoms and boys more externalizing symptoms. Distress was the strongest parental factor mediating children's internalizing/externalizing symptoms. The quality of the studies was appraised as low (n = 12), medium (n = 12), and high (n = 10). Conclusion: Gender-based interventions should be designed for children and parents. The studies reviewed were cross-sectional, so long-term patterns and outcomes could not be predicted. Future researchers might consider a longitudinal approach to determine the long-term effects of the pandemic on children's internalizing and externalizing symptoms. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022385284, identifier: CRD42022385284.