Past endolithic life in metamorphic ocean crust

The known deep subsurface biosphere on Earth persists in diversified habitats, including deep within igneous rocks of the oceanic crust. Here, we extend the range of the deep subsurface biosphere to metamorphic ocean crust of a subduction zone. We report fossilised life in zeolite facies rocks, which formed by low grade metamorphism, from the southern Mariana trench. Dense carbonaceous spheroids, filaments, and Frutexites-like structures are preserved in these rocks, which are enriched in organic carbon but depleted in 13C. The distinct difference in the GDGT-0 vs. crenarchaeol and the branched vs. isoprenoid tetraether values between the inner and outer portions of these rocks indicate the in situ production of organic carbon. We demonstrate that these structures may result from the past activity of potential chemolithoautotrophs within the metamorphic crust, as implied by their morphologies, Raman spectra, carbon isotopes, and biomarker signatures, as well as the Fe oxidation state within whole rocks. We propose that fluid-rock reactions at temperatures within the tolerance of life during low grade metamorphism contributed to microbial subsistence within the biotope. The low grade metamorphic ocean crust of the subduction zone likely represents Earth’s deepest, and one of its largest, microbial ecosystems, which may potentially influence the deep carbon cycle

Evidence for oxygenic photosynthesis half a billion years before the Great Oxidation Event

The early Earth was characterized by the absence of oxygen in the ocean–atmosphere system, in contrast to the well-oxygenated conditions that prevail today. Atmospheric concentrations first rose to appreciable levels during the Great Oxidation Event, roughly 2.5–2.3 Gyr ago. The evolution of oxygenic photosynthesis is generally accepted to have been the ultimate cause of this rise, but it has proved difficult to constrain the timing of this evolutionary innovation. The oxidation of manganese in the water column requires substantial free oxygen concentrations, and thus any indication that Mn oxides were present in ancient environments would imply that oxygenic photosynthesis was ongoing. Mn oxides are not commonly preserved in ancient rocks, but there is a large fractionation of molybdenum isotopes associated with the sorption of Mo onto the Mn oxides that would be retained. Here we report Mo isotopes from rocks of the Sinqeni Formation, Pongola Supergroup, South Africa. These rocks formed no less than 2.95 Gyr ago in a nearshore setting. The Mo isotopic signature is consistent with interaction with Mn oxides. We therefore infer that oxygen produced through oxygenic photosynthesis began to accumulate in shallow marine settings at least half a billion years before the accumulation of significant levels of atmospheric oxygen

HomeAssist: une plateforme d'assistance domiciliaire pour le maintien à domicile basée sur une approche interdisciplinaire

International audienceThis paper presents HomeAssist: an assisted living platform aims to support aging in place. This platform was designed using a human-centered approach. It offers assistive services, addressing the main aspects of daily life: activities of daily living, home and user safety, and social participation. HomeAssist introduces key novel features: (1) it covers multiple aspects of daily life, addressing a variety of needs of older adults; (2) it provides customiza-tion mechanisms, adapting assistance to the user's abilities while preventing autonomy losses; (3) it relies on context awareness, delivering timely assistance; and, (4) it revolves around a unified user interface to achieve usability. All these features play a key role towards achieving high acceptance of HomeAssist and supporting autonomy effectively, as shown by our field study

Exploring the usability of a connected autonomous vehicle human machine interface designed for older adults

Users of Level 4–5 connected autonomous vehicles (CAVs) should not need to intervene with the dynamic driving task or monitor the driving environment, as the system will handle all driving functions. CAV human-machine interface (HMI) dashboards for such CAVs should therefore offer features to support user situation awareness (SA) and provide additional functionality that would not be practical within non-autonomous vehicles. Though, the exact features and functions, as well as their usability, might differ depending on factors such as user needs and context of use. The current paper presents findings from a simulator trial conducted to test the usability of a prototype CAV HMI designed for older adults and/or individuals with sensory and/or physical impairments: populations that will benefit enormously from the mobility afforded by CAVs. The HMI was developed to suit needs and requirements of this demographic based upon an extensive review of HMI and HCI principles focused on accessibility, usability and functionality [1, 2], as well as studies with target users. Thirty-one 50-88-year-olds (M 67.52, three 50–59) participated in the study. They experienced four seven-minute simulated journeys, involving inner and outer urban settings with mixed speed-limits and were encouraged to explore the HMI during journeys and interact with features, including a real-time map display, vehicle status, emergency stop, and arrival time. Measures were taken pre-, during- and post- journeys. Key was the System Usability Scale [3] and measures of SA, task load, and trust in computers and automation. As predicted, SA decreased with journey experience and although cognitive load did not, there were consistent negative correlations. System usability was also related to trust in technology but not trust in automation or attitudes towards computers. Overall, the findings are important for those designing, developing and testing CAV HMIs for older adults and individuals with sensory and/or physical impairments

Investigating older adults’ preferences for functions within a human-machine interface designed for fully autonomous vehicles

© Springer International Publishing AG, part of Springer Nature 2018. Compared to traditional cars, where the driver has most of their attention allocated on the road and on driving tasks, in fully autonomous vehicles it is likely that the user would not need to intervene with driving related functions meaning that there will be little need for HMIs to have features and functionality relating to these factors. However, there will be an opportunity for a range of other interactions with the user. As such, designers and researchers need to have an understanding of what is actually needed or expected and how to balance the type of functionality they make available. Also, in HMI design, the design principles need to be considered in relation to a range of user characteristics, such as age, and sensory, cognitive and physical ability and other impairments. In this study, we proposed an HMI specially designed for connected autonomous vehicles with a focus on older adults. We examined older adults’ preferences of CAV HMI functions, and, the degree to which individual differences (e.g., personality, attitude towards computers, trust in technology, cognitive functioning) correlate with preferences for these functions. Thirty-one participants (M age = 67.52, SD = 7.29), took part in the study. They had to interact with the HMI and rate its functions based on the importance and likelihood of using them. Results suggest that participants prefer adaptive HMIs, with journey planner capabilities. As expected, as it is a CAV HMI, the Information and Entertainment functions are also preferred. Individual differences have limited relationship with HMI preferences

Earth: Atmospheric Evolution of a Habitable Planet

Our present-day atmosphere is often used as an analog for potentially habitable exoplanets, but Earth's atmosphere has changed dramatically throughout its 4.5 billion year history. For example, molecular oxygen is abundant in the atmosphere today but was absent on the early Earth. Meanwhile, the physical and chemical evolution of Earth's atmosphere has also resulted in major swings in surface temperature, at times resulting in extreme glaciation or warm greenhouse climates. Despite this dynamic and occasionally dramatic history, the Earth has been persistently habitable--and, in fact, inhabited--for roughly 4 billion years. Understanding Earth's momentous changes and its enduring habitability is essential as a guide to the diversity of habitable planetary environments that may exist beyond our solar system and for ultimately recognizing spectroscopic fingerprints of life elsewhere in the Universe. Here, we review long-term trends in the composition of Earth's atmosphere as it relates to both planetary habitability and inhabitation. We focus on gases that may serve as habitability markers (CO2, N2) or biosignatures (CH4, O2), especially as related to the redox evolution of the atmosphere and the coupled evolution of Earth's climate system. We emphasize that in the search for Earth-like planets we must be mindful that the example provided by the modern atmosphere merely represents a single snapshot of Earth's long-term evolution. In exploring the many former states of our own planet, we emphasize Earth's atmospheric evolution during the Archean, Proterozoic, and Phanerozoic eons, but we conclude with a brief discussion of potential atmospheric trajectories into the distant future, many millions to billions of years from now. All of these 'Alternative Earth' scenarios provide insight to the potential diversity of Earth-like, habitable, and inhabited worlds.Comment: 34 pages, 4 figures, 4 tables. Review chapter to appear in Handbook of Exoplanet

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field