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In this work we present a revision of an open-split-based dual inlet system for elemental and isotope ratio mass spectrometers (IRMS), which was developed by the Climate and Environmental Physics Division of the University of Bern two decades ago. Besides discussing the corresponding improvements we show that with this inlet system (NIS-II) external precisions can be achieved that are high enough to perform measurements of multiply-substituted isotopologues (clumped isotopes) on pure gases. For the clumped isotope ratios 35/32 and 36/32 of oxygen we achieved standard deviations of 3.4 ⋅ 10−9 and 4.9 ⋅ 10−9, respectively, that we calculated from 60 interval means (20 s integration) of pure oxygen gas measurements. Moreover, we report various performance tests and show that with the NIS-II delta values of various air components can be measured with precisions of order tenths of per meg and higher. In addition, we demonstrate that our new open-split-based dual inlet system allows to measure some of these delta values with significantly higher precisions than a NIS-I (precursor of NIS-II) and a conventional changeover-valve-based dual inlet system (tests performed with an Elementar iso DUAL INLET). The greatest discrepancies between the NIS-II and the iso DUAL INLET were observed for δ32/28 and δ44/28; the differences in the external precisions were 4 per meg and 35 per meg (10 SA/STD measurements), respectively. With respect to the reproducibility of δ32/28 means, the deviations from a reference value were even larger, namely around 0.1 ‰. Due to the successful preliminary tests regarding measurements of clumped isotope ratios, we will continue our work in this area to perform clumped isotope studies according to common practices.

Biogenic gases carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are regularly analysed in many environments to understand elemental cycling and processes through the ecosphere. They are also of interest to atmospheric chemists for their role in climate change. The Elementar Isoprime TraceGas, coupled with Elementar isotope ratio mass spectrometer (IRMS), has been a key to a significant number of studies providing data on the isotopes of these key dynamic molecules. We shall review some of the notable publications and modifications in the field of atmospheric gas monitoring.The development of the recently launched isoprime precisION IRMS has permitted a new generation of control and automation of the mass spectrometer and integrated peripherals. This has greatly improved the accessibility and versatility of the instruments as a whole. Taking advantage of the inherent benefits of the isoprime precisION, the iso FLOW GHG has been developed for high performance analysis of CO2, N2O and CH4 as a successor to the isoprime TraceGas, and has the capacity to be rapidly customised for specific needs with options for N2 and N2O analysis, analysis of hydrogen isotopes in CH4, and high precision and sensitivity measurement of nitrate-derived N2O as generated from denitrifier techniques. We present an outline of the latest generation hardware available to the gas researcher and explain how it’s standard modes and configurations take biogenic gas analysis further than before.

We investigate the strong acceleration properties of the radiation reaction force and identify a new and promising limiting acceleration feature in the Eliezer-Ford-O'Connell model; in the strong field regime, for many field configurations, we find an upper limit to acceleration resulting in a bound to the rate of radiation emission. If this model applies, strongly accelerated particles are losing energy at a much slower pace than predicted by the usual radiation reaction benchmark, the Landau-Lifshitz equation, which certainly cannot be used in this regime. We explore examples involving various "constant" electromagnetic field configurations and study particle motion in a light plane wave as well as in a material medium., 14 pages, 4 figures, 1 table

Biogenic gases carbon dioxide, methane and nitrous oxide are regularly analysed in many environments to understand elemental cycling and processes through the ecosphere. They are also of interest to atmospheric chemists for their role in climate change. The Isoprime Tracegas has been key to a large amount of studies providing data on the isotopes of these key dynamic molecules. We shall review some of the notable publications and modifications in the field of atmospheric gas monitoring.The development of the isoprime precisION mass spectrometer has permitted a new generation of control and automation of the mass spectrometer and integrated peripherals. This has greatly improved the accessibility and versatility of the instruments as a whole.Taking advantage of the inherent benefits of the isoprime precisION the iso FLOW GHG has been developed for high performance analysis of CO2, N2O and CH4 and has the capacity to be rapidly customised for specific needs with options for N2 and N2O, Hydrogen isotopes in CH4 and denitrifier analysis.

We introduce Ego4D, a massive-scale egocentric video dataset and benchmark suite. It offers 3,670 hours of daily-life activity video spanning hundreds of scenarios (household, outdoor, workplace, leisure, etc.) captured by 931 unique camera wearers from 74 worldwide locations and 9 different countries. The approach to collection is designed to uphold rigorous privacy and ethics standards with consenting participants and robust de-identification procedures where relevant. Ego4D dramatically expands the volume of diverse egocentric video footage publicly available to the research community. Portions of the video are accompanied by audio, 3D meshes of the environment, eye gaze, stereo, and/or synchronized videos from multiple egocentric cameras at the same event. Furthermore, we present a host of new benchmark challenges centered around understanding the first-person visual experience in the past (querying an episodic memory), present (analyzing hand-object manipulation, audio-visual conversation, and social interactions), and future (forecasting activities). By publicly sharing this massive annotated dataset and benchmark suite, we aim to push the frontier of first-person perception. Project page: https://ego4d-data.org/, Comment: To appear in the Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2022. This version updates the baseline result numbers for the Hands and Objects benchmark (appendix)

Since its introduction in 2018, EPIC-KITCHENS has attracted attention as the largest egocentric video benchmark, offering a unique viewpoint on people's interaction with objects, their attention, and even intention. In this paper, we detail how this large-scale dataset was captured by 32 participants in their native kitchen environments, and densely annotated with actions and object interactions. Our videos depict nonscripted daily activities, as recording is started every time a participant entered their kitchen. Recording took place in 4 countries by participants belonging to 10 different nationalities, resulting in highly diverse kitchen habits and cooking styles. Our dataset features 55 hours of video consisting of 11.5M frames, which we densely labelled for a total of 39.6K action segments and 454.2K object bounding boxes. Our annotation is unique in that we had the participants narrate their own videos after recording, thus reflecting true intention, and we crowd-sourced ground-truths based on these. We describe our object, action and. anticipation challenges, and evaluate several baselines over two test splits, seen and unseen kitchens. We introduce new baselines that highlight the multimodal nature of the dataset and the importance of explicit temporal modelling to discriminate fine-grained actions e.g. 'closing a tap' from 'opening' it up., Preprint for paper at IEEE TPAMI. arXiv admin note: substantial text overlap with arXiv:1804.02748

In resource-limited settings, the lack of decentralized molecular diagnostic testing and sparse access to centralized medical facilities can present a critical barrier to timely diagnosis, treatment, and subsequent control and elimination of infectious diseases. Isothermal nucleic acid amplification methods, including reverse transcription loop-mediated isothermal amplification (RT-LAMP), are well-suited for decentralized point-of-care molecular testing in minimal infrastructure laboratories since they significantly reduce the complexity of equipment and power requirements. Despite reduced complexity, however, there is still a need for a constant heat source to enable isothermal nucleic acid amplification. This requirement poses significant challenges for laboratories in developing countries where electricity is often unreliable or unavailable. To address this need, we previously developed a low-cost, electricity-free heater using an exothermic reaction thermally coupled with a phase change material. This heater achieved acceptable performance, but exhibited considerable variability. Furthermore, as an enabling technology, the heater was an incomplete diagnostic solution. Here we describe a more precise, affordable, and robust heater design with thermal standard deviation