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Older adults (OAs) often prioritize positive over negative information during word processing, termed as positivity bias. However, it is unclear how OAs update the affective representation of a word in contexts. The present study examined whether age-related positivity bias influences the update of the affective representation of a word in different emotional contexts. In Experiment 1 (web-based), younger and older participants read positive and negative target words in positive and negative contexts and rated the valence of the target words. Negative contexts biased the ratings more than positive ones, reflecting a negativity bias during offline valence evaluation in both age groups. In Experiment 2 (EEG), another group of participants read positive and negative target words in positive and negative contexts first, and then the same target words again, and made valence judgment on the target words. OAs showed a larger P2 (180–300 ms) difference before and after contexts for positive target words than younger adults (YAs). This suggests OAs’ early attention to positive features of words in contexts. YAs showed a larger late positive complex (LPC) difference for target words before and after negative contexts than before and after positive contexts, while older adults showed comparable LPC effects across all the conditions. This suggests that YAs use negative contexts to update the affective representation of a word, whereas OAs do so in both positive and negative contexts. Our findings supported a reduced negativity bias in OAs in using (emotional) contexts to update the affective neural representation of a word. 

We report an experimental realization of a modified counterfactual communication protocol that eliminates the dominant environmental trace left by photons passing through the transmission channel. Compared to Wheeler’s criterion for inferring past particle paths, as used in prior protocols, our trace criterion provides stronger support for the claim of the counterfactuality of the communication. We verify the lack of trace left by transmitted photons via tagging the propagation arms of an interferometric device by distinct frequency-shifts and finding that the collected photons have no frequency shift which corresponds to the transmission channel. As a proof of principle, we counterfactually transfer a quick response code image with sufficient fidelity to be scanned with a cell phone. 

Abstract Self-testing allows one to characterise quantum systems under minimal assumptions. However, existing schemes rely on quantum nonlocality and cannot be applied to systems that are not entangled. Here, we introduce a robust method that achieves self-testing of individual systems by taking advantage of contextuality. The scheme is based on the simplest contextuality witness for the simplest contextual quantum system—the Klyachko-Can-Binicioğlu-Shumovsky inequality for the qutrit. We establish a lower bound on the fidelity of the state and the measurements as a function of the value of the witness under a pragmatic assumption on the measurements. We apply the method in an experiment on a single trapped⁴⁰Ca⁺using randomly chosen measurements and perfect detection efficiency. Using the observed statistics, we obtain an experimental demonstration of self-testing of a single quantum system. 

Stimulated Raman projection tomography is a label-free volumetric chemical imaging technology allowing three-dimensional (3D) reconstruction of chemical distribution in a biological sample from the angle-dependent stimulated Raman scattering projection images. However, the projection image acquisition process requires rotating the sample contained in a capillary glass held by a complicated sample rotation stage, limiting the volumetric imaging speed, and inhibiting the study of living samples. Here, we report a tilt-angle stimulated Raman projection tomography (TSPRT) system which acquires angle-dependent projection images by utilizing tilt-angle beams to image the sample from different azimuth angles sequentially. The TSRPT system, which is free of sample rotation, enables rapid scanning of different views by a tailor-designed four-galvo-mirror scanning system. We present the design of the optical system, the theory, and calibration procedure for chemical tomographic reconstruction. 3D vibrational images of polystyrene beads and C. elegans are demonstrated in the C-H vibrational region.