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Kohlenstoffmanagement in Baden-Württemberg - Weichenstellungen für Klimaneutralität und Industriestandort
No full textQuantifying glare phenomena in patients with different intraocular lenses using a standard and modified clinical straylight meter
No full textPurpose:
To assess if differences in straylight can be detected in patients implanted with multifocal intraocular lenses (IOL) using a standard and modified clinical straylight measurement.
Setting:
A tertiary care university eye clinic
Design:
Comparative cross-sectional study
Methods:
Straylight was measured at 7 and 2.5 degrees using the standard and modified C-Quant (Oculus Optikgeräte) devices. Two measurements per eye and angle were obtained. Logarithm of the straylight parameter (s) at both angles and its increase between 7 and 2.5 degrees were compared between study groups.
Results:
Thirty-eight patients (67 eyes) were included in total: 12 patients (24 eyes) implanted with Tecnis Synergy (Johnson & Johnson Vision), 13 patients (25 eyes) with Clareon PanOptix (Alcon), and 13 patients (18 eyes) with monofocal lenses. The mean (±standard deviation) straylight values at 7 degrees were 0.98±0.16 log(s) with Synergy, 1.03±0.14 log(s) with PanOptix, and 1.05±0.22 log(s) with monofocal controls (p=0.864). At 2.5 degrees, they were 1.55±0.09 log(s) with Synergy, 1.34±0.10 log(s) with PanOptix, and 1.29±0.21 log(s) with monofocal IOLs (p<0.001). The increase in straylight at 2.5 degrees was 0.57±0.13 log(s) for Synergy, 0.31±0.11 log(s) for PanOptix, and 0.25±0.10 log(s) for monofocal controls (p<0.001).
Conclusions:
Straylight measurements at 2.5 degrees using the modified technique showed higher straylight levels with Synergy when compared to PanOptix and monofocal IOLs, while the standard technique did not detect differences between IOLs. Straylight testing at smaller angles emerges as a sensitive measure to identify multifocal designs posing an increased risk of inducing photic phenomena in pseudophakic patients
Logic Gating of Photochemical States Utilizing Nitroxide‐Free Radicals
No full textUtilizing a fused isoindoline nitroxide-styrylpyrene system (StyPyNO), this work presents an interrogation into the effects of the radical spin on the [2+2] photocycloaddition of styrlpyrene and explores the photoswitchability of the system. Through irradiation with both broadband lamps and laser light sources, the influence of the nitroxide moiety on photoreactivity was analyzed and compared with both styryl pyrene and diamagnetic controls. The presence of the radical spin prevented the intermolecular [2+2] photocycloaddition observed from the control systems, instead allowing for a trans–cis photoisomerism under identical 420 nm irradiation conditions. Studies into the triplet lifetimes of the radical containing and control systems allowed for deeper understanding around the mechanism of photoreactivity. The system explored presents a means of controlling photo reaction progression not only via wavelength of irradiation, but also via the presence or removal of the unpaired electron within the nitroxide moiety. This in turn presents the potential for a dual gated chemical/photoswitchable system
Bit-reproducible parallel phylogenetic tree inference
No full textMotivation
Phylogenetic trees describe the evolutionary history among biological species based on their genomic data. Maximum likelihood (ML) based phylogenetic inference tools search for the tree and evolutionary model that best explain the observed genomic data. Given the independence of likelihood score calculations between different genomic sites, parallel computation is commonly deployed. This is followed by a parallel summation over the per-site scores to obtain the overall likelihood score of the tree. However, basic arithmetic operations on IEEE 754 floating-point numbers, such as addition and multiplication, inherently introduce rounding errors. Consequently, the order by which floating-point operations are executed affects the exact resulting likelihood value since these operations are not associative. Moreover, parallel reduction algorithms in numerical codes re-associate operations as a function of the core count and cluster network topology, inducing different round-off errors. These low-level deviations can cause heuristic searches to diverge and induce high-level result discrepancies (e.g. yield topologically distinct phylogenies). This effect has also been observed in multiple scientific fields beyond phylogenetics.
Results
We observe that varying the degree of parallelism results in diverging phylogenetic tree searches (high-level results) for over 31% out of 10 179 empirical datasets. More importantly, 8% of these diverging datasets yield trees that are statistically significantly worse than the best-known ML tree for the dataset (AU-test, P < .05). To alleviate this, we develop a variant of the widely used phylogenetic inference tool RAxML-NG, which does yield bit-reproducible results under varying core-counts, with a slowdown of only 0%–12.7% (median 0.8%) on up to 768 cores. For this, we introduce the ReproRed reduction algorithm, which yields bit-identical results under varying core-counts, by maintaining a fixed operation order that is independent of the communication pattern. ReproRed is thus applicable to all associative reduction operations—in contrast to competitors, which are confined to summation. Our ReproRed reduction algorithm only exchanges the theoretical minimum number of messages, overlaps communication with computation, and utilizes fast base-cases for local reductions. ReproRed is able to all-reduce (via a subsequent broadcast) operands across 48–768 cores in 19.7–48.61 μs, thereby exhibiting a slowdown of 13%–93% over a non-reproducible all-reduce algorithm. ReproRed outperforms the state-of-the-art reproducible all-reduction algorithm ReproBLAS (offers summation only) beyond 10 000 elements per core. In summary, we re-assess non-reproducibility in parallel phylogenetic inference, present the first bit-reproducible parallel phylogenetic inference tool, as well as introduce a general algorithm and open-source code for conducting reproducible associative parallel reduction operations.
Availability and implementation
ReproRed: https://doi.org/10.5281/zenodo.15004918 (LGPL)—Reproducible RAxML-NG version https://doi.org/10.5281/zenodo.15017407 (GPL
Step-by-Step Wavelength Resolved Analysis of Photo-Diels–Alder Step Growth Synthesis
No full textPhotoinduced step-growth polymerizations are an important avenue to soft matter materials. However, photopolymerizations are highly challenging to unpack into their individual reaction steps and to determine the efficiency of these individual steps as a function of wavelength. Herein, we introduce a combined synthetic and photochemical action plot methodology to isolate the two key reaction steps of a step-growth photo-Diels–Alder polymerization and independently map their wavelength-dependent quantum yields with monochromatic resolution. To characterize our system with the highest possible precision, we introduce a photochemical action plot method based on the absorption of a constant number of photons at each wavelength. Our specific photopolymer system is based on a bis-o-methylbenzaldehyde (oMBA) species where the two reaction sites are electronically connected. Our approach initially entails the selective synthesis of a mono-Diels–Alder adduct from the symmetrical difunctional oMBA, enabling the precise mapping of the blue-shift in wavelength-dependent reactivity between the first and second addition. Our final molecule represents a distinct system of five fused rings, which matches the macromolecular system
Digitalisiertes Lernen in der Lehramtsausbildung am Karlsruher Institut für Technologie (KIT)
No full textBest practices for a proper evaluation and conversion of physical property equations in superconductors: the examples of WHH formulation, Bean model and other cases of interest
No full textIn recent years there have been growing concerns about the proper evaluation of physical properties
of superconductors, in particular for quantities extracted from magnetic characterizations.
Errors can and often do occur due to the following issues: (i) several measurement instruments
still use Gaussian & cgs-emu units instead of the preferable International System (SI) units; (ii)
there are decades of valuable publications where, however, equations were expressed in Gaussian &
cgs-emu or other unit systems or where constants were normalized to unity, which requires proper
understanding and unit conversion in order to correctly evaluate the measured physical quantities;
(iii) the conversion between unit systems sometimes appears challenging and may not be properly
performed. In this paper we will describe how to properly convert physical quantities relevant
for the evaluation of magnetic and other properties focusing on the still most used unit systems,
SI and Gaussian & cgs-emu. We will provide examples of how to properly verify and understand
the physical formulae. We will include examples for the correct method to determine the critical
current density Jc of a superconductor from the measurement of its magnetic hysteresis loop
through the Bean model, and the correct conversion to SI of the equations for Hc2(T) according to
the Werthamer–Helfand–Hohenberg formulation. The goals of this paper are to make the readers
aware of the unit conversion issue, to provide useful hands-on tools for proper conversion and to
strongly encourage future exclusive use of the SI units and formulae
Robust and efficient electroreduction of CO to CO in a modified zero-gap electrochemical cell
No full textExcellent energy efficiency and system stability are critical factors guiding the practical application of carbon dioxide reduction reaction (CORR ) systems. This work promotes reduction reaction kinetics in a modified zero-gap electrolyzer by regulating the operation temperature and pressure. The energy efficiency of the CORR system is enhanced, such as 52.6 % at a current of 1.2 A under alkaline conditions and 49.4 % under neutral conditions, with the characteristics of low voltage and high Faradaic efficiency. In addition, the optimization of the reaction microenvironment effectively alleviates the precipitation issue, enabling the system to operate stably for more than 100 h, with a Faradaic efficiency of more than 90 % for CO generation. Engineering-integrated electrochemistry inspires the future development of CORR technology
District Future – Urban Lab (Quartier Zukunft – Labor Stadt). Long-term participatory sustainable development of an existing urban district in Karlsruhe
No full textDynamisches Monitoring einer Eisenbahnbrücke mit Beschleunigungssensoren und Profillaserscanning
No full textStructural Health Monitoring (SHM) stellt eine Möglichkeit dar, alternde Bauwerke effizient zu schützen und damit die Sicherheit der Tragwerke und ihre nachhaltige Nutzung zu garantieren. Im Kontext des dynamischen SHM liegt der Fokus in der Regel auf der Bestimmung der Eigenfrequenzen der überwachten Bauwerke, da diese eine zentrale Rolle für die Sicherheit, Stabilität und Lebensdauer der Bauwerke spielen. Klassischerweise werden für das SHM punktuelle Messinstrumente, insbesondere Geber, eingesetzt, die die zeitkontinuierliche Überwachung einzelner Objektpunkte erlauben. Großer Nachteil dieser Vorgehensweise ist, dass die Geber an den Bauwerksstrukturen montiert werden müssen und sie somit keine berührungslose Erfassung der Eigenfrequenzen erlauben. Hinzu kommt, dass insbesondere für die Bestimmung der Amplituden und der unterschiedlichen Eigenformen die Messpunkte sorgfältig vorab ausgewählt werden müssen. Das terrestrische Laserscanning (TLS) erlaubt dagegen die quasi-kontinuierliche und berührungslose Erfassung ganzer Messobjekte und behebt damit die Nachteile der klassischen punktbasierten Messverfahren.
In dieser Veröffentlichung werden Überwachungsmessungen einer Eisenbahnbrücke unter dynamischer Last vorgestellt. Im Zuge der Messkampagne wurde die Brücke sowohl mit klassischen Beschleunigungssensoren, mit Tachymetrie als auch mit Profillaserscanning überwacht. Aus den Daten werden Eigenfrequenzen und Eigenformen der Brücke abgeleitet. Die abgeleiteten Eigenfrequenzen zeigen eine große Übereinstimmung der Ergebnisse der drei Messverfahren und unterstreichen das große Potential des Laserscannings im Kontext der dynamischen Bauwerksüberwachung