Spatial and Temporal Occurrence of Preformed Nitrate Anomalies in the Subtropical Ocean

Preformed nitrate (PreNO3) was formulated to act as a conservative tracer of oceancirculation after accounting for the stoichiometry of marine biochemical reactions involving oxygen and nitrate. However, PreNO3 anomalies have been identified within the shallow subtropical ocean, that describe the biological consumption or production of oxygen without assumed stoichiometric changes in nitrate, which still have yet to be fully explained. The mechanisms proposed to drive the formation of PreNO3 anomalies are: vertically migrating phytoplankton (VMP), the export and subsequent remineralization of N-deficient transparent exopolymer particles (TEP, e.g. marine gels), and the remineralization of N-poor dissolved organic matter (DOM). Observations from the subtropical Pacific and Atlantic oceans taken by twenty Biogeochemical Argo (Bio-Argo) profiling floats which collectively span from 2007 to 2019 have been used to answer two questions related to PreNO3 anomalies. What is the seasonality and geographic extents of subsurface negative PreNO3 anomalies and euphotic zone positive PreNO3 anomalies in the global subtropical ocean? What biogeochemical processes capable of generating PreNO3 anomalies are consistent with the seasonality and spatial extents found in the Bio-Argo float records? Euphotic zone positive PreNO3 anomalies are consistently observed between 30˚S and 50˚N, whereas subsurface negative PreNO3 anomalies are absent in parts of the Equatorial West Pacific Ocean. The remineralization of N-poor DOM has been shown to contribute to PreNO3 anomaly formation by previous studies and has been accounted for in this study. The geographic extents of the remaining PreNO3 anomalies are consistent with previous observations of VMP taxa throughout the global subtropical ocean. The seasonal timing of euphotic zone positive PreNO3 anomalies in relation to subsurface negative PreNO3 anomalies indicates that both VMP and the export and remineralization of N-deficient TEP contribute to the formation of PreNO3 anomalies. Since VMP include large diatoms that produce ballasted organic matter while TEP may only sink slowly before remineralization, further investigation into the mechanisms generating PreNO3 anomalies is needed to assess their roles in the future biological carbon pump in an expanding subtropical ocean ecosystem

Spatial and Temporal Occurrence of Preformed Nitrate Anomalies in the Subtropical Ocean

Preformed nitrate (PreNO3) was formulated to act as a conservative tracer of oceancirculation after accounting for the stoichiometry of marine biochemical reactions involving oxygen and nitrate. However, PreNO3 anomalies have been identified within the shallow subtropical ocean, that describe the biological consumption or production of oxygen without assumed stoichiometric changes in nitrate, which still have yet to be fully explained. The mechanisms proposed to drive the formation of PreNO3 anomalies are: vertically migrating phytoplankton (VMP), the export and subsequent remineralization of N-deficient transparent exopolymer particles (TEP, e.g. marine gels), and the remineralization of N-poor dissolved organic matter (DOM). Observations from the subtropical Pacific and Atlantic oceans taken by twenty Biogeochemical Argo (Bio-Argo) profiling floats which collectively span from 2007 to 2019 have been used to answer two questions related to PreNO3 anomalies. What is the seasonality and geographic extents of subsurface negative PreNO3 anomalies and euphotic zone positive PreNO3 anomalies in the global subtropical ocean? What biogeochemical processes capable of generating PreNO3 anomalies are consistent with the seasonality and spatial extents found in the Bio-Argo float records? Euphotic zone positive PreNO3 anomalies are consistently observed between 30˚S and 50˚N, whereas subsurface negative PreNO3 anomalies are absent in parts of the Equatorial West Pacific Ocean. The remineralization of N-poor DOM has been shown to contribute to PreNO3 anomaly formation by previous studies and has been accounted for in this study. The geographic extents of the remaining PreNO3 anomalies are consistent with previous observations of VMP taxa throughout the global subtropical ocean. The seasonal timing of euphotic zone positive PreNO3 anomalies in relation to subsurface negative PreNO3 anomalies indicates that both VMP and the export and remineralization of N-deficient TEP contribute to the formation of PreNO3 anomalies. Since VMP include large diatoms that produce ballasted organic matter while TEP may only sink slowly before remineralization, further investigation into the mechanisms generating PreNO3 anomalies is needed to assess their roles in the future biological carbon pump in an expanding subtropical ocean ecosystem

Too sick to drive : how motion sickness severity impacts human performance

There are multiple concerns surrounding the development and rollout of self-driving cars. One issue has largely gone unnoticed - the adverse effects of motion sickness as induced by self-driving cars. The literature suggests conditionally, highly and fully autonomous vehicles will increase the onset likelihood and severity of motion sickness. Previous research has shown motion sickness can have a significant negative impact on human performance. This paper uses a simulator study design with 51 participants to assess if the scale of motion sickness is a predictor of human performance degradation. This paper finds little proof that subjective motion sickness severity is an effective indicator of the scale of human performance degradation. The performance change of participants with lower subjective motion sickness is mostly statistically indistinguishable from those with higher subjective sickness. Conclusively, those with even acute motion sickness may be just as affected as those with higher sickness, considering human performance. Building on these results, it could indicate motion sickness should be a consideration for understanding user ability to regain control of a self-driving vehicle, even if not feeling subjectively unwell. Effectiveness of subjective scoring is discussed and future research is proposed to help ensure the successful rollout of self-driving vehicles

The crystal structure of calcite III

The crystal structure of calcite III has been deduced from existing high pressure powder X-ray diffraction patterns, based on the assumption that it is a displacive modification of the calcite I structure. The structure is monoclinic with space group C2 and a Z of 6. There are two Ca and two C positions, and five O positions, and atom coordinates have been refined by distance-least-squares methods to give reasonable octahedral coordination for Ca and parallel, planar CO_3 groups. Unit cell parameters refined from a published powder diffraction pattern at 4.1 GPa are: a = 8.746(8)Å; b = 4.685(5)Å; c = 8.275(8)Å; and β= 94.4°. The structure has a calculated density of 2.949 Mg/m³ at 4.1 GPa which is less than that of aragonite at this pressure and consistent with early piston cylinder studies. This implies that calcite III is indeed a metastable intermediary between calcite I and aragonite

East Java: Cenozoic basins, volcanoes and ancient basement

East Java on land is divided here into four broadly EW zones: (1) the Southern Mountains Zone, an Eocene to Miocene volcanic arc, separated by (2) the present-day volcanic arc from (3) the Kendeng Zone which was the main Cenozoic depocentre in onshore East Java; and to the north (4) the Rembang Zone which represents the edge of the Sunda Shelf. Several synthems separated by unconformities can be identified and correlated between the different zones. There is a regional angular unconformity above Upper Cretaceous and older basement. The oldest rocks above the unconformity range from Mid Eocene to Lower Oligocene and record a gradual transgression and, in SE Java, an increase in volcanic material up-section.After an intra-Oligocene sea-level fall, volcanic material from the arc dominated in the Southern Mountains and Kendeng Zones while in the Rembang Zone carbonate deposition continued. In the Early Miocene, activity in the Southern Mountains Volcanic Arc culminated in a major eruptive phase at 20 Ma ± 1 Ma, similar in scale to the Pleistocene eruptions of Toba. To the north carbonate deposition was interrupted by clastic input containing reworked basement and Eocene material. The Mid Miocene was a period of reworking and carbonate sedimentation. In the Late Miocene volcanic activity recommenced at the position of the present-day arc and there was a series of deformation events throughout East Java. Volcanism has played an important role in the development of East Java, providing a source of material and contributing to subsidence by flexural loading. Provenance studies and dating of zircons provide insight into the basement character and suggest that continental crust of Gondwana (possibly Western Australian) origin lies beneath part of the Southern Mountains Zone. It is suggested that continental Sundaland provided very little, if any, terrigenous material to East Java in the Cenozoic

Exploring the utility of EDA and skin temperature as individual physiological correlates of motion sickness

Motion sickness (MS) is known to be a potentially limiting factor for future self-driving vehicles – specifically in regards to occupant comfort and well-being. With this as a consideration comes the desire to accurately measure, track and even predict MS state in real-time. Previous research has considered physiological measurements to measure MS state, although, this is mainly measured after an MS exposure and not throughout exposure(s) to a MS task. A unique contribution of this paper is in the real-time tracking of subjective MS alongside real-time physiological measurements of Electrodermal Activity (EDA) and skin temperature. Data was collected in both simulator-based (controlled) and on-road (naturalistic) studies. 40 participants provided at total of 61 data sets, providing 1,603 minutes of motion sickness data for analysis. This study is in agreement that these measures are related to MS but evidenced a total lack of reliability for these measures at an individual level for both simulator and on-road experimentation. It is likely that other factors, such as environment and emotional state are more impactful on these physiological measures than MS itself. At a cohort level, the applicability of physiological measures is not considered useful for measuring MS accurately or reliably in real-time. Recommendations for further research include a mixed-measures approach to capture other data types (such as subject activity) and to remove contamination of physiological measures from environmental changes

The nouveau roman and the aesthetics of modernity and postmodernity

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Understanding and managing motion sickness in future vehicles : innovation report

Almost everyone is susceptible to motion sickness, and around one in three people are known to be highly susceptible. It has been argued that the use of automated vehicles will increase motion sickness severity and onset frequency for those who already regularly suffer from it, as well as for those who are susceptible, but don’t regularly get motion sick in traditional vehicles. This is primarily due to the engagement with non-driving activities which cause sensory conflict, the relinquishing of control which prevents apprehension of current and upcoming motion, and the limited ability to self-mitigate due to potential vehicle designs and the inability to take control of the dynamic driving task in a fully automated vehicle. This research first contextualised the relationship between motion sickness and future automotive technologies – covering both research focused driving simulators as well as ‘real-world’ use cases for on-road partially to fully automated vehicles. A framework for future research was developed and three core projects were established, positioned to cover the breadth of the field. Following this framework, the first project explored the impact of motion sickness on human performance, this was followed by the development of a method of reducing susceptibility to motion sickness and finally, objective measurements of motion sickness were explored. Motion sickness is a consideration for not only the day-to-day utility of future automated vehicles, but also within the development and simulator-based testing of such technology. Despite the myriad benefits of driving simulators for developing future technology, one significant side effect is simulator-induced motion sickness or ‘simulation sickness’. The first project, using both simulator-based and real-world experimentation, explored the effect of motion sickness on human performance – informing our understanding about transferability of simulator data to ‘real-world’ as well as providing insights into the relationship between motion sickness and productivity for future vehicles. The second research project proposes, develops, tests and validates a novel method of reducing motion sickness susceptibility by way of specific visual-cognitive training activities. Experimentation began using a high fidelity driving simulator where it was first shown how it is possible to increase visuospatial skills through a novel assimilation and application of a pen-and-paper training pack. Subsequently, this increased visuospatial skill reduced both subjective simulator sickness by 58%, and dropouts due to severe motion sickness by 60%. This simulator-based study was followed up with an on-road study where the visuospatial training pack was further validated for ‘real-world’ utility and was shown to be responsible for a reduction in motion sickness by 52% across the experimental group. Further to the core findings presented, an industry-focused workshop identified ways in which this new knowledge can be exploited for consumer-focused utility. This research also contributes to the fundamental understanding of the relationship between visuospatial ability and motion sickness susceptibility. Through extensive simulator-based and on-road motion sickness experimentation, the third research project pulls together physiological and subjective motion sickness data to explore concepts for objectively measuring and detecting motion sickness in real-time. Building upon literature from both motion sickness and machine learning fields, a wide range of data types, from demographics, to vehicle conditions, to occupant activity and route design are highlighted to be potentially useful in future objective motion sickness studies. Based on these sources of data, and many more, a new model is proposed through which motion sickness related data can be collected to aid in the objective measurement of motion sickness. The research conducted here provides a novel contribution in understanding motion sickness related human performance degradation and provides an interesting discussion about the impact this may have for both simulator trials, and automated vehicle utility. Through the design and validation of a novel training tool for reducing motion sickness susceptibility (in simulators and ‘real-world’) this research adds to the knowledge about our fundamental understanding of motion sickness and provides an innovative solution to address the issue of motion sickness. Further contributions are found within the research looking at objective measurements of motion sickness and among other various design recommendations