Influence of common lighting conditions and time-of-day on the effort-related cardiac response

Melanopic stimuli trigger diverse non-image-forming effects. However, evidence of a melanopic contribution to acute effects on alertness and performance is inconclusive, especially under common lighting situations. Effects on cognitive performance are likely mediated by effort-related physiological changes. We assessed the acute effects of lighting in three scenarios, at two times of day, on effort-related changes to cardiac contraction as indexed by the cardiac pre-ejection period (PEP). In a within-subject design, twenty-seven participants performed a cognitive task thrice during a morning and a late-afternoon session. We set the lighting at 500 lux in all three lighting scenarios, measured horizontally at the desk level, but with 54 lux, 128 lux, or 241 lux melanopic equivalent daylight illuminance at the eye level. Impedance cardiography and electrocardiography measurements were used to calculate PEP, for the baseline and task period. A shorter PEP during the task represents a sympathetic heart activation and therefore increased effort. Data were analysed with linear mixed-effect models. PEP changes depended on both the light scene and time of day (p = 0.01 and p = 0.002, respectively). The highest change (sympathetic activation) occurred for the medium one of the three stimuli (128 lux) during the late-afternoon session. However, effect sizes for the singular effects were small, and only for the combined effect of light and time of day middle-sized. Performance scores or self-reported scores on alertness and task demand did not change with the light scene. In conclusion, participants reached the same performance most efficiently at both the highest and lowest melanopic setting, and during the morning session. The resulting U-shaped relation between melanopic stimulus intensity and PEP is likely not dependent solely on intrinsic ipRGC stimuli, and might be moderated by extrinsic cone input. Since lighting situations were modelled according to current integrative lighting strategies and real-life indoor light intensities, the result has implications for artificial lighting in a work environment

Incommensurate ground state of double-layer quantum Hall systems

Double-layer quantum Hall systems possess interlayer phase coherence at sufficiently small layer separations, even without interlayer tunneling. When interlayer tunneling is present, application of a sufficiently strong in-plane magnetic field $B_\parallel > B_c$ drives a commensurate-incommensurate (CI) transition to an incommensurate soliton-lattice (SL) state. We calculate the Hartree-Fock ground-state energy of the SL state for all values of $B_\parallel$ within a gradient approximation, and use it to obtain the anisotropic SL stiffness, the Kosterlitz-Thouless melting temperature for the SL, and the SL magnetization. The in-plane differential magnetic susceptibility diverges as $(B_\parallel - B_c)^{-1}$ when the CI transition is approached from the SL state.Comment: 12 pages, 7 figures, to be published in Physical Review

Practical Timing Side-Channel Attacks on Memory Compression

Compression algorithms have side channels due to their data-dependent operations. So far only the compression-ratio side channel was exploited, e.g., the compressed data size. In this paper, we present Decomp+Time, the first memory compression attack exploiting a timing side channel in compression algorithms. While Decomp+Time affects a much broader set of applications than prior work, a key challenge is precisely crafting attacker-controlled compression payloads to enable the attack with sufficient resolution. We develop an evolutionary fuzzer, Comprezzor, to find effective Decomp+Time payloads that optimize latency differences and find payloads that are so effective that decompression timing can even be exploited in remote Decomp+Time attacks across the Internet. Decomp+Time has a capacity of 9.73 kB/s locally, and 10.72 bit/min across the internet (14 hops, > 700 miles). Using Comprezzor, we develop attacks that leak data byte-by-byte in four different case studies: First, we leak 1.50 bit/min from Memcached on a remote server running a PHP application. Second, we leak database records with 2.69 bit/min from PostgreSQL, managed by a Python-Flask application, over the internet. Third, we leak secrets with 49.14 bit/min locally from ZRAM-compressed pages on Linux. Fourth, we leak internal heap pointers from the V8 engine within the Google Chrome browser on a system using ZRAM. This highlights the importance of re-evaluating the use of compression on sensitive data even if the application is only reachable via a remote interface

Eine Frage des Flächensparens: Wo können 1 Milliarde Photovoltaik-Module in Deutschland installiert werden?

Dieser Beitrag fokussiert auf die bauwerksintegrierte Photovoltaik (BIPV) und widmet sich den folgenden Fragen: Wie kann das Flächenpotenzial deutscher Gebäudefassaden in Bezug auf die Eignung für BIPV überschlägig erfasst, beschrieben und nach verschiedenen Gebäudefunktionen bewertet werden? Wo können künftig 1 Milliarde PV-Module in Deutschland installiert werden? Untersucht wird das theoretische Fassadenflächenpotenzial (ohne Berücksichtigung von Fenster- und Türflächenanteilen, ohne Bewertung der tatsächlichen Solareinstrahlung) in Deutschland, um zu analysieren, ob ausreichend Fassadenflächen für die Bereitstellung der benötigten elektrischen Leistung vorhanden sind. Es wird eine Bestandsanalyse für alle Gebäude in Deutschland durchgeführt, die darauf abzielt, jene Gebäudefunktion mit besonderer Eignung für BIPV unter Berücksichtigung der Fassadenausrichtung zu bestimmen. Außerdem wird ermittelt, auf welche Stadt- und Gemeindetypen besonders relevante Gebäude entfallen

A combined fMRI and EMG study of emotional contagion following partial sleep deprivation in young and older humans

Sleep deprivation is proposed to inhibit top-down-control in emotion processing, but it is unclear whether sleep deprivation affects emotional mimicry and contagion. Here, we aimed to investigate effects of partial sleep deprivation on emotional contagion and mimicry in young and older humans. Participants underwent partial sleep deprivation (3 h sleep opportunity at the end of night), crossed-over with a full sleep condition in a balanced order, followed by a functional magnetic resonance imaging and electromyography (EMG) experiment with viewing of emotional and neutral faces and ratings of emotional responses. The final sample for main analyses was n = 69 (n = 36 aged 20–30 years, n = 33 aged 65–75 years). Partial sleep deprivation caused decreased activation in fusiform gyri for angry faces and decreased ratings of happiness for all stimuli, but no significant effect on the amygdala. Older participants reported more anger compared to younger participants, but no age differences were seen in brain responses to emotional faces or sensitivity to partial sleep deprivation. No effect of the sleep manipulation was seen on EMG. In conclusion, emotional contagion, but not mimicry, was affected by sleep deprivation. Our results are consistent with the previously reported increased negativity bias after insufficient sleep. The Stockholm sleepy brain study: effects of sleep deprivation on cognitive and emotional processing in young and old. https://clinicaltrials.gov/ct2/show/NCT02000076

A multimodal brain imaging dataset on sleep deprivation in young and old humans

The Stockholm Sleepy Brain Study I is a functional brain imaging study of 48 younger (20-30 years) and 36 older (65-75 years) healthy participants, with magnetic resonance imaging after normal sleep and partial sleep deprivation in a crossover design. We performed experiments investigating emotional mimicry, empathy for pain, and cognitive reappraisal, as well as resting state functional magnetic resonance imaging (fMRI). We also acquired T1- and T2-weighted structural images and diffusion tensor images (DTI). On the night before imaging, participants were monitored with ambulatory polysomnography and were instructed to sleep either as usual or only three hours. Participants came to the scanner the following evening. Besides MRI scanning, participants underwent behavioral tests and contributed blood samples, which have been stored in a biobank and used for DNA analyses. Participants also completed a variety of self-report measures. The resulting multimodal dataset may be useful for hypothesis generation or independent validation of effects of sleep deprivation and aging, as well as investigation of cross-sectional associations between the different outcomesNoneManuscrip