Now in the Network

Network technologies have played an increasingly prominent role in sound art practices over the last forty years. The consequent creative possibilities associated with space and locality are clearly apparent: networks enable connections between geographically remote locations, and allow the creation of new virtual spaces for sound art to inhabit. Less immediately apparent—though equally significant—are the ways in which network technologies have enabled artists to explore temporal relationships in their work. In particular, network technologies inevitably involve latency—a short time delay between the moment a signal is created at one location and the moment it is perceived at another. Taking traditional notated music practice as a point of reference, this chapter considers a number of case studies in which sound artists have explored new types of temporal relationships in their work, as a consequence of their use of network technologies. This investigation is framed in the context of Bergson’s concept of durée and Clarke’s concept of subject position.

Rhinovirus prevalence as indicator for efficacy of measures against SARS-CoV-2

Background Non-pharmaceutical measures to control the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) should be carefully tuned as they can impose a heavy social and economic burden. To quantify and possibly tune the efficacy of these anti-SARS-CoV-2 measures, we have devised indicators based on the abundant historic and current prevalence data from other respiratory viruses. Methods We obtained incidence data of 17 respiratory viruses from hospitalized patients and outpatients collected by 37 clinics and laboratories between 2010-2020 in Germany. With a probabilistic model for Bayes inference we quantified prevalence changes of the different viruses between months in the pre-pandemic period 2010-2019 and the corresponding months in 2020, the year of the pandemic with noninvasive measures of various degrees of stringency. Results We discovered remarkable reductions δ in rhinovirus (RV) prevalence by about 25% (95% highest density interval (HDI) [−0.35,−0.15]) in the months after the measures against SARS-CoV-2 were introduced in Germany. In the months after the measures began to ease, RV prevalence increased to low pre-pandemic levels, e.g. in August 2020 δ=−0.14 (95% HDI [−0.28,0.12]). Conclusions RV prevalence is negatively correlated with the stringency of anti-SARS-CoV-2 measures with only a short time delay. This result suggests that RV prevalence could possibly be an indicator for the efficiency for these measures. As RV is ubiquitous at higher prevalence than SARS-CoV-2 or other emerging respiratory viruses, it could reflect the efficacy of noninvasive measures better than such emerging viruses themselves with their unevenly spreading clusters.

Revealing Ultrafast Two-Electron Transfer Over Tryptophan with Mass Spectrometry

Electron transfer crucial to bioenergetics is ubiquitously present in biological systems but most of them escape from direct observations. By using tryptophan and its derivatives with 1-CH₃, 2-CH₃, 5-CH₃ and 5-OH substitutions as model molecules, we have unambiguously demonstrated successive two-electron transfer to tryptophan as well as electronic and vibrational excited molecular dissociation with mass spectrometry. The ultra-short time delay between two electrons down to sub-attosecond over a distance less than 10 Å was found to cause the strong coupling of electronic and vibrational excitations that was validated by the observation of radical-radical coupling. Intramolecular H migrations along with two-electron transfer was demonstrated with H/D exchange and ¹³C stable isotope labeling. This proposed technique allows us to observe the ultrafast electron transfer from tryptophan to the heme group in myoglobin proteins. It bridges electron transfer to energy transfer that has been revealed in FRET alone. FeII (porph•‐) and FeI (porph•‐) resulting from one- and two-electron transfer, respectively, have been unambiguously identified<br>

Revealing Ultrafast Two-Electron Transfer Over Tryptophan with Mass Spectrometry

Electron transfer crucial to bioenergetics is ubiquitously present in biological systems but most of them escape from direct observations. By using tryptophan and its derivatives with 1-CH₃, 2-CH₃, 5-CH₃ and 5-OH substitutions as model molecules, we have unambiguously demonstrated successive two-electron transfer to tryptophan as well as electronic and vibrational excited molecular dissociation with mass spectrometry. The ultra-short time delay between two electrons down to sub-attosecond over a distance less than 10 Å was found to cause the strong coupling of electronic and vibrational excitations that was validated by the observation of radical-radical coupling. Intramolecular H migrations along with two-electron transfer was demonstrated with H/D exchange and ¹³C stable isotope labeling. This proposed technique allows us to observe the ultrafast electron transfer from tryptophan to the heme group in myoglobin proteins. It bridges electron transfer to energy transfer that has been revealed in FRET alone. FeII (porph•‐) and FeI (porph•‐) resulting from one- and two-electron transfer, respectively, have been unambiguously identified<br>

The GALAH survey: temporal chemical enrichment of the galactic disc

ABSTRACT We present isochrone ages and initial bulk metallicities ($\rm [Fe/H]_{bulk}$, by accounting for diffusion) of 163 722 stars from the GALAH Data Release 2, mainly composed of main-sequence turn-off stars and subgiants ($7000\, \mathrm{ K}&gt; T_{\mathrm{ eff}}&gt; 4000\, \mathrm{ K}$ and $\log g&gt;3$ dex). The local age–metallicity relationship (AMR) is nearly flat but with significant scatter at all ages; the scatter is even higher when considering the observed surface abundances. After correcting for selection effects, the AMR appears to have intrinsic structures indicative of two star formation events, which we speculate are connected to the thin and thick discs in the solar neighbourhood. We also present abundance ratio trends for 16 elements as a function of age, across different $\rm [Fe/H]_{bulk}$ bins. In general, we find the trends in terms of [X/Fe] versus age from our far larger sample to be compatible with studies based on small (∼100 stars) samples of solar twins, but we now extend them to both sub- and supersolar metallicities. The α-elements show differing behaviour: the hydrostatic α-elements O and Mg show a steady decline with time for all metallicities, while the explosive α-elements Si, Ca, and Ti are nearly constant during the thin-disc epoch (ages $\lesssim \! 12$ Gyr). The s-process elements Y and Ba show increasing [X/Fe] with time while the r-process element Eu has the opposite trend, thus favouring a primary production from sources with a short time delay such as core-collapse supernovae over long-delay events such as neutron star mergers.

A Restarting Strategy for Back-EMF-Based Sensorless Permanent Magnet Synchronous Machine Drive

Safely starting a spinning position sensorless controlled permanent magnet synchronous machine is difficult because the current controller does not include information regarding the motor position and speed for suppressing the back-electromotive force (EMF)-induced current. This paper presents a restarting strategy for back-EMF-based sensorless drives. In the proposed strategy, the existing back-EMF and position estimator are used and no additional algorithm or specific voltage vector injection is required. During the restarting period, the current controller is set to a particular state so that the back-EMF estimator can rapidly estimate motor voltage without using rotor position and speed. Then, this voltage is used to decouple the back-EMF of the motor in the current controller in order to suppress the induced current. After the back-EMF is decoupled from the current controller, sensorless control can be restored with the estimated position and speed. The experimental results indicated that the induced current can be suppressed within four to five sampling periods regardless of the spinning conditions. Because of the considerably short time delay, the motor drive can restart safely from various speeds and positions without causing overcurrent fault.