3,867 research outputs found

    Information actors beyond modernity and coloniality in times of climate change:A comparative design ethnography on the making of monitors for sustainable futures in Curaçao and Amsterdam, between 2019-2022

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    In his dissertation, Mr. Goilo developed a cutting-edge theoretical framework for an Anthropology of Information. This study compares information in the context of modernity in Amsterdam and coloniality in Curaçao through the making process of monitors and develops five ways to understand how information can act towards sustainable futures. The research also discusses how the two contexts, that is modernity and coloniality, have been in informational symbiosis for centuries which is producing negative informational side effects within the age of the Anthropocene. By exploring the modernity-coloniality symbiosis of information, the author explains how scholars, policymakers, and data-analysts can act through historical and structural roots of contemporary global inequities related to the production and distribution of information. Ultimately, the five theses propose conditions towards the collective production of knowledge towards a more sustainable planet

    Planetary Hinterlands:Extraction, Abandonment and Care

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    This open access book considers the concept of the hinterland as a crucial tool for understanding the global and planetary present as a time defined by the lasting legacies of colonialism, increasing labor precarity under late capitalist regimes, and looming climate disasters. Traditionally seen to serve a (colonial) port or market town, the hinterland here becomes a lens to attend to the times and spaces shaped and experienced across the received categories of the urban, rural, wilderness or nature. In straddling these categories, the concept of the hinterland foregrounds the human and more-than-human lively processes and forms of care that go on even in sites defined by capitalist extraction and political abandonment. Bringing together scholars from the humanities and social sciences, the book rethinks hinterland materialities, affectivities, and ecologies across places and cultural imaginations, Global North and South, urban and rural, and land and water

    The terminator region of tidally locked M-dwarf exoplanets in 3-d general circulation models

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    The impressive sensitivity of the James Webb Space Telescope has made it possible to study the atmospheres of planets beyond the solar system. It will soon be followed by space missions aiming specifically at this goal, such as the Ariel mission, Twinkle, and the Habitable Worlds Observatory. One category of exoplanet has drawn interest because of its potential to harbour temperate climates with liquid surface water—and therefore potentially life. These are rocky planets orbiting cool M-class stars, or "M-Earths." Stellar population trends and observing biases lead to a high proportion of potentially habitable, terrestrial planets falling into this category. Because of the low temperatures of their host stars, however, habitable worlds of this type are found in close orbits where they are likely to be tidally locked. As the solar system has no tidally locked planets, our knowledge of their atmospheric circulation is currently limited to theoretical modelling. Past modelling work has shown that the asymmetrical irradiation of tidally locked planets results in characteristic circulation regimes which have profound consequences for observations. Atmospheric retrievals, which use statistical methods to fit 1-D atmospheric models to observational data and quantify the confidence of the fit, are not yet able to account for the 3-D nature of this circulation. For planets with large spatial variation in environmental conditions caused by tidal locking, 1-D models are not able to capture the differences and interconnections between planetary regions such as the dayside, nightside, and planetary limb or terminator. In addition, planetary atmospheres exhibit variation over time, potentially resulting in differences in retrieved properties between observing visits or even between different phases of a planet’s orbit. Accounting for 4-D circulation effects in atmospheric retrievals first requires a theoretical understanding of the impact of global-scale phenomena such as atmospheric waves and horizontal transport on conditions at the planetary limb, and then requires incorporation of this knowledge into the retrieval pipeline in the form of, for example, parameterisations. In this thesis, I address the first requirement: the theoretical understanding of the effects of fully modelled 4-D atmospheric circulation on the planetary limb, the region probed by transmission spectroscopy, on tidally locked planets. I focus in particular on effects caused by the global propagation of atmospheric waves and by horizontal transport of clouds and hazes. In Chapter 2, I show that that the atmospheric dynamics on the tidally locked Proxima Centauri b support a longitudinally asymmetric stratospheric wind oscillation (LASO), analogous to Earth’s quasi-biennial oscillation (QBO). The LASO has a vertical extent of 35–55 km, a period of 5–6.5 months, and a peak-to-peak wind speed amplitude of -70 to +130 ms−1 with a maximum at an altitude of 41 km. Unlike the QBO, the LASO displays longitudinal asymmetries related to the asymmetric thermal forcing of the planet and to interactions with the resulting stationary Rossby waves. The equatorial gravity wave sources driving the LASO are localised in the deep convection region at the substellar point and in a jet exit region near the western terminator, unlike the QBO, for which these sources are distributed uniformly around the planet. Longitudinally, the western terminator experiences the highest wind speeds and undergoes reversals earlier than other longitudes. The antistellar point only experiences a weak oscillation with a very brief, low-speed westward phase. The QBO on Earth is associated with fluctuations in the abundances of water vapour and trace gases such as ozone which are also likely to occur on exoplanets if these gases are present. Strong fluctuations in temperature and the abundance of atmospheric species at the terminators will need to be considered when interpreting atmospheric observations of tidally locked exoplanets. In Chapter 3, I investigate the presence of cloud cover at the planetary limb of water-rich Earth-like planets, which is likely to weaken chemical signatures in transmission spectra and impede attempts to characterise these atmospheres. Based on observations of Earth and solar system worlds, exoplanets with atmospheres should have both short-term weather and long-term climate variability, implying that cloud cover may be less during some observing periods. I identify and describe a mechanism driving periodic clear sky events at the terminators in simulations of tidally locked Earth-like planets. A feedback between dayside cloud radiative effects, incoming stellar radiation and heating, and the dynamical state of the atmosphere, especially the zonal wavenumber-1 Rossby wave identified in past work on tidally locked planets, leads to oscillations in Rossby wave phase speeds and in the position of Rossby gyres and results in advection of clouds to or away from the planet’s eastern terminator. I study this oscillation in simulations of Proxima Centauri b, TRAPPIST 1-e, and rapidly rotating versions of these worlds located at the inner edge of their stars’ habitable zones. I simulate time series of the transit depths of the 1.4 µm water feature and 2.7 µm carbon dioxide feature. The impact of atmospheric variability on the transmission spectra is sensitive to the structure of the dayside cloud cover and the location of the Rossby gyres, but none of my simulations have variability significant enough to be detectable with current methods. In Chapter 4, I study the interaction between the atmospheric circulation and photochemical hazes and describe the resulting haze abundances at the terminator. Transmission spectroscopy supports the presence of unknown, light-scattering aerosols in the atmospheres of many exoplanets. The complexity of factors influencing the formation, 3-D transport, radiative impact, and removal of aerosols makes it challenging to match theoretical models to the existing data. My study simplifies these factors to focus on the interaction between planetary general circulation and haze distribution at the planetary limb. I use an intermediate complexity general circulation model, ExoPlaSim, to simulate idealised organic haze particles as radiatively active tracers in the atmospheres of tidally locked terrestrial planets for a range of rotation rates. I find three distinct 3-D spatial haze distributions, corresponding to three circulation regimes, each with a different haze profile at the limb. All regimes display significant terminator asymmetry. In my parameter space, super-Earth-sized planets with rotation periods greater than 13 days have the lowest haze optical depths at the terminator, supporting the choice of slower rotators as observing targets. My thesis supports the existence of characteristic forms of temporal and spatial variability on tidally locked planets which will undoubtedly impact observations and inform our understanding of climate conditions on the surface. Overall, the effects of purely dynamical variability may be too small to be detected for Earth-like planets (but potentially detectable for larger ones). The impact of the atmospheric circulation on the distribution of clouds and hazes, on the other hand, is likely to affect even observations of terrestrial planets due to the highly scattering nature of these aerosols and will need to be accounted for in atmospheric retrievals

    Choreographing tragedy into the twenty-first century

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    What makes a tragedy? In the fifth century BCE this question found an answer through the conjoined forms of song and dance. Since the mid-twentieth century, and the work of the Tanztheater Wuppertal Pina Bausch, tragedy has been variously articulated as form coming apart at the seams. This thesis approaches tragedy through the work of five major choreographers and a director who each, in some way, turn back to Bausch. After exploring the Tanztheater Wuppertal’s techniques for choreographing tragedy in chapter one, I dedicate a chapter each to Dimitris Papaioannou, Akram Khan, Trajal Harrell, Ivo van Hove with Wim Vandekeybus, and Gisèle Vienne. Bringing together work in Queer and Trans* studies, Performance studies, Classics, Dance, and Classical Reception studies I work towards an understanding of the ways in which these choreographers articulate tragedy through embodiment and relation. I consider how tragedy transforms into the twenty-first century, how it shapes what it might mean to live and die with(out) one another. This includes tragic acts of mythic construction, attempts to describe a sense of the world as it collapses, colonial claims to ownership over the earth, and decolonial moves to enact new ways of being human. By developing an expanded sense of both choreography and the tragic one of my main contributions is a re-theorisation of tragedy that brings together two major pre-existing schools, to understand tragedy not as an event, but as a process. Under these conditions, and the shifting conditions of the world around us, I argue that the choreography of tragedy has and might continue to allow us to think about, name, and embody ourselves outside of the ongoing catastrophes we face

    Integrating Traditional and Close Range Photogrammetric Bathymetric Reconstructions to Enhance Predictions of Fish Abundance and Distribution on the NSW Coast

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    The physical structure of marine habitat is a key determinant of the distribution and abundance of marine biota. Photogrammetry is a new method of obtaining bathymetric reconstructions using overlapping imagery. It is associated with several potential improvements over traditional bathymetric reconstruction methods (e.g., hydroacoustic and optical remote sensing), including finer resolutions, 3D mesh surfaces, and novel metrics of structural complexity. However, the greater cost of photogrammetric data collection requires evaluation of its purported benefits to marine research. This thesis objectively assessed the potential for photogrammetry to improve predictions of marine biota abundance and distribution. Chapter 2 undertook a quantitative review and metanalysis of latest research and the relative performance of metrics. It indicated common metrics, e.g., surface-rugosity, may not always be the best performing. Chapter 3 systematically explored the relationships between metrics derived from common bathymetric reconstructions and reduced a 2,000 predictor dataset to 100 predictors, whilst maximising information captured. Metric relative performance was assessed in Chapter 4. Photogrammetric metrics contributed to 22 / 35 fish species and 10 / 15 trophic-mobility group best performing abundance models and helped explain a third more variability compared to traditional methods. Chapter 5 extrapolated (‘engineered’) broad-scale photogrammetric metrics from traditional metrics to help alleviate the cost of photogrammetry. Using an independent dataset, the variance 26 / 50 fish species distribution models was explained best when engineered photogrammetric metrics were included. These findings help confirm the purported benefits to marine research associated with photogrammetric metrics, which would likely improve predictions of the distribution and abundance of fish, and likely other marine biota, across Australia and worldwide. Engineered metrics would allow greater model performance to be translated to broad-extents required by marine spatial prioritisation, conservation and management. Notably, traditional metrics were important for some fish species and groups, and future studies should seek to combine these methods wherever possible

    Sex determination, adaptive divergence, and the role of inversions in ecotypes of the intertidal snail Littorina saxatilis

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    Sex determination and sex chromosomes exhibit great diversity within and between species, in their mechanisms and drivers, and over space and time. Why and how this variation has evolved remains poorly understood and empirical evidence remains scarce. Species with young, emerging sex determination systems are useful tools for understanding these processes, in particular in species with labile sex determination between environments. The role of ecology in sex-specific selection is unclear but likely to be central to these processes. Understanding the drivers and mechanisms for adaptive divergence, reproductive isolation and sex determination in the same populations will be crucial and allows the interface between these processes to be tested. In this thesis, I investigate the above processes in the intertidal snail, Littorina saxatilis, utilising a combination of genomic approaches based on previous field sampling and manipulative experiments in natural populations. I uncover evidence for a multigenic female-heterogametic sex determining system in operation in multiple populations that involves genomic regions on two linkage groups and multiple sex-linked inversions. I characterise patterns of sex- and ecotype-specific genomic associations of SNPs and inversions, revealing the role of habitat-dependent sex-specific selection and the concurrent role of inversions in the differentiation of both sexes and ecotypes. Through experimental testing, I quantify differential survival and movement of locally adapted ecotypes across habitats, specifically evidencing the role of divergent selection and habitat choice in reproductive isolation between ecotypes. I further show that arrangement frequencies of two sex-linked inversions are mediated by sex-, ecotype-, and habitat-based selective interactions. Together, my findings shed light on drivers and mechanisms of sex determination, ecotype divergence, and the role of inversions in L. saxatilis. More generally, they offer insight into the relationship between sex- and environment-based selection and transitions in sex- determination systems across heterogeneous environments, uncovering an ideal system for future work

    Integrated Geophysical Analysis of Passive Continental Margins: Insights into the Crustal Structure of the Namibian Margin from Magnetotelluric, Gravity, and Seismic Data

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    Passive continental margin research amalgamates the investigation of many broad topics, such as the emergence of oceanic crust, lithospheric stress patterns and plume-lithosphere interaction, reservoir potential, methane cycle, and general global geodynamics. Central tasks in this field of research are geophysical investigations of the structure, composition, and dynamic of the passive margin crust and upper mantle. A key practice to improve geophysical models and their interpretation, is the integrated analysis of multiple data, or the integration of complementary models and data. In this thesis, I compare four different inversion results based on data from the Namibian passive continental margin. These are a) a single method MT inversion; b) constrained inversion of MT data, cross-gradient coupled with a fixed structural density model; c) cross-gradient coupled joint inversion of MT and satellite gravity data; d) constrained inversion of MT data, cross-gradient coupled with a fixed gradient velocity model. To bridge the formal analysis of geophysical models with geological interpretations, I define a link between the physical parameter models and geological units. Therefore, the results from the joint MT and gravity inversion (c) are correlated through a user-unbiased clustering analysis. This clustering analysis results in a distinct difference in the signature of the transitional crust south of- and along the supposed hot-spot track Walvis Ridge. I ascribe this contrast to an increase in magmatic activity above the volcanic center along Walvis Ridge. Furthermore, the analysis helps to clearly identify areas of interlayered massive, and weathered volcanic flows, which are usually only identified in reflection seismic studies as seaward dipping reflectors. Lastly, the clustering helps to differentiate two types of sediment cover. Namely, one of near-shore, thick, clastic sediments, and one of further offshore located, more biogenic, marine sediments
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