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Freedom in a Time of Climate Catastrophe
Get PDFThe failure of Western publics to respond congruently to the scale of the climate catastrophe should be understood as a lack of freedom. This article describes four ways in which collective agency is likely to be exercised in the coming decades in relation to the climate crisis: climate governance, reactionary populism, green authoritarianism, and pluriform localism. The prospect that these may fail to achieve climate goals within the necessary time horizon raises the question of the meaning of freedom if the window of opportunity for adequate climate action is closing. Drawing on Walter Benjamin's theological and materialist conception of messianic time in the face of the loss of the future, we can delineate a Christian account of freedom indexed to participation in the cross and resurrection of Christ
The Milky Way Stellar Halo Is Twisted and Doubly Broken: Insights from DESI DR2 Milky Way Survey Observation
Get PDFUsing K giants from the second data release (DR2) of the Dark Energy Spectroscopic Instrument (DESI) Milky Way Survey, we measure the shape, orientation, radial profile, and density anisotropies of the Milky Way (MW) stellar halo over 8 kpc < rGC < 200 kpc. We identify a triaxial stellar halo (axis ratio 10:8:7), 43° tilted from the disk, showing two break radii at ∼16 and ∼76 kpc, likely associated with Gaia-Sausage/Enceladus and the Large Magellanic Cloud (LMC), respectively. The inner stellar halo (<30 kpc) is oblate and aligned with the disk, whereas the outer stellar halo becomes prolate and perpendicular to the disk, consistent with the vast polar structure of MW satellites. The twisted halo may arise from the disk−halo angular momentum shift triggered by the infall of a massive satellite. The anisotropic density distribution of the stellar halo is also measured, with successful reidentification of the Hercules-Aquila Cloud North/South (HAC-N/S) overdensity and the Virgo overdensity (VOD). Break radii are found at 15 and 30 kpc for VOD and HAC-N/S, respectively. We identify the LMC transient density wake with a break radius at 60 kpc in the Pisces overdensity region. We also find new observational evidence of the LMC collective density wake, by showing a break radius at ∼100 kpc in the northern Galactic cap with a clear density peak at 90 kpc. In the end, we found that more metal-poor halo stars are more radially extended. Our results provide important clues to the assembly and evolution of the MW stellar halo under the standard cosmic structure formation framework
Investigation of Magnetic Topology and Triggering Mechanisms of a C-class Flare and Active Region Blowout Jet
Get PDFCoronal jets are collimated plasma eruptions that are ubiquitous in the solar atmosphere. Believed to be triggered by magnetic reconnection, these jets can contribute to various phenomena, including coronal heating and particle acceleration. Coronal jets are a contemporary area of research, with their onset mechanism meriting further attention. Importantly, a subclass of jets, the blowout jets, is particularly interesting because of their broad spire, suggesting substantial 3D reconnection between open and closed field lines involving 3D null points. Consequently, here we explore the onset of a blowout jet associated with Active Region SPoCA 29093 detected by the Spatial Possibilistic Clustering Algorithm (SPoCA). This AR produced a C1.1-class flare on 2022 November 10, and we investigate it using a data-constrained magnetohydrodynamic simulation initiated with a non-force-free field extrapolation of the photospheric magnetic field. Key elements of the extrapolated field lines are the presence of a 3D null and a magnetic flux rope (MFR) colocated with the jet activity region, the evolution of which is further traced in the simulation. The simulation suggests that magnetic reconnection is responsible for the evolution of the MFR, leading to a near-simultaneous onset of the flare and jet as observed by the Atmospheric Imaging Assembly/Solar Dynamics Observatory. In particular, the simulation shows spontaneous creation and annihilation of 3D null pairs via magnetic reconnection near the jet region. Such spontaneous null pair generation, in principle, can trigger or contribute to coronal jets, opening up a new avenue for further research
Older but wiser? Are older entrepreneurs more likely to become social entrepreneurs?
No full textThe paper explores the relationship between an entrepreneur’s age and their decision to engage in social entrepreneurship, defined as entrepreneurial activity pursuing social, environmental, or community-oriented objectives. Drawing on construal level theory (CLT) and an individual-level application of the resource-based view (RBV), we investigate how life-stage transitions and resource endowments jointly shape entrepreneurs’ orientation toward socially and sustainability-oriented ventures. Based on a sample of 184,319 entrepreneurs and using the construal level theory and the resource-based view, our study finds that entrepreneurs in the age group (45-65), and who are middle- and higher-income households, are more likely to engage in social entrepreneurship than both younger individuals and those aged 65 and above. A notable discovery is that entrepreneurial experience and education do not play a significant role in the decision to engage in social entrepreneurship. These findings challenge conventional wisdom and underscore the unique dynamics of social entrepreneurship by demonstrating that entrepreneurs' temporal psychological distance influences their engagement in social entrepreneurship-related activity and resource use. Our results have implications for the aging population. Overall, the study contributes to research on entrepreneurial life stages by demonstrating how temporal perspective and resource conditions jointly relate to participation in social and sustainability-oriented entrepreneurship
Enhanced Landslide Investigations through Advanced DInSAR Techniques: The Ivancich Case Study, Assisi, Italy
No full textWe extensively exploit advanced Differential SAR Interferometry (DInSAR) techniques for enhanced landslide investigations. We focus on the Ivancich area, Assisi, Central Italy, which is affected by a deep-seated landslide investigated through in-situ surveys. For this area, large data sets of SAR acquisitions were collected by the C-band ERS-1/2 and ENVISAT sensors (from April 1992 to November 2010), and by the X-band radars of the COSMO-SkyMed (CSK) constellation (from December 2009 to February 2012). We concentrate on the advanced DInSAR technique referred to as Small BAseline Subset (SBAS) approach, benefiting of its capability to generate deformation time series at full spatial resolution and from multi-sensor SAR data. This allows us to present one of the first examples for a landslide area of ERS-1/2 --- ENVISAT deformation time series exceeding 18 years. The results allowed characterizing the long-term behaviour of the landslide, and identifying sectors of the unstable slope affected by different deformation dynamics. Analysis of the CSK data set, characterized by a reduced revisit time and improved spatial resolution, resulted in a 15-time larger point density with respect to the ERS-ENVISAT measurements, allowing to investigate nearly all the buildings (and, in many cases, portions of build- ings) in the landslide area. Lastly, we present an innovative modelling approach based on the effective integration of the DInSAR measurements with traditional geological and geotechnical information, providing deeper insights on the kinematical evolution of the landslide. We consider our analysis a prototype example that can be extended to different geological and geotechnical conditions, providing significant advances in the understanding of ground deformations induced by active landslides
Robust galaxy image decompositions with differential evolution optimization and the problem of classical bulges in and beyond the nearby Universe
No full textDeconstructing galaxies through two-dimensional decompositions has been shown to be a powerful technique to derive the physical properties of stellar structures in galaxies. However, most studies employ fitting algorithms that are prone to be trapped in local minima, or involve subjective choices. Furthermore, when applied on samples beyond the nearby Universe, results on the fraction of classical bulges in disc galaxies do not agree with studies on nearby galaxies. The latter studies point to a small fraction of classical bulges, possibly challenging our merger-driven picture of galaxy formation. Therefore, understanding the discrepancy between observations in and beyond the nearby Universe is of paramount importance. In this paper, I use a sample of 16 nearby galaxies drawn from the TIMER project, which previously have been shown to not host classical bulges, and perform decompositions applying different methodologies and employing the original images as well as artificially redshifted images. I show that the Differential Evolution algorithm is able to provide accurate measurements of structural properties with little subjective intervention, correctly indicating the presence of nuclear discs (not classical bulges). However, I also show that when the physical spatial resolution is not adequate, a systematic overestimation of the photometric bulge Sérsic index leads to the false conclusion of the presence of classical bulges. I discuss how this may be the root cause of the discrepancy mentioned above, and point out how this issue may be a problem even with data from facilities such as Euclid, the Hubble Space Telescope (HST), and the James Webb Space Telescope (JWST)
Bayesian emulation of deterioration curves using quadratic and B-spline hierarchical models
No full textThe stability of geotechnical infrastructure assets, such as cuttings and embankments, is crucial to the safe and efficient delivery of transport services. The successful emulation of geotechnical models of deterioration of infrastructure slopes has the potential to inform slope design, maintenance and remediation by introducing the time dependency of deterioration into geotechnical asset management. We have performed computer experiments of deterioration, measured by the factor of safety (FoS), for a set of cutting slope geometries and soil properties that are common in the southern UK. Whilst computer experiments are an extremely useful and cost-effective method of better understanding deterioration mechanisms, it would not be practical to run enough experiments to understand relations between high-dimensional inputs and outputs. Therefore, we trained a fully-Bayesian Gaussian process emulator using an ensemble of 75 computer experiments to predict the FoS. We construct two different emulator models, one approximating the FoS temporal evolution with a quadratic model and one approximating the temporal evolution with a B-spline model; and we emulated their parameters. We also compare the ability of our models to predict failure time. The developed models could be used to inform infrastructure cutting slope design and management, and extend serviceable life
A systematic review and meta‐synthesis of qualitative studies of alopecia: Managing identity and appearance changes
No full textPurpose: Alopecia is a medical dermatology condition resulting in multiple psychosocial negative consequences in identity and appearence. Despite numerous qualitative studies examining the experience of people with alopecia, a comprehensive synthesis is lacking. This can obscure progress in research and minimize the impact of psychosocial support people with alopecia can receive. This systematic meta‐synthesis aimed to critically integrate the existing literature to enhance psychological understanding of how people with alopecia manage issues about identity and appearance changes, and provide some evidence‐based recommendations for clinicians working in the area of psychodermatology. Methods: A systematic search of six databases: APA PsycInfo (OVID), Medline (OVID), Embase (OVID), CINAHL (EBSCO) and Scopus identified 22 eligible studies on the lived experience of alopecia among adults, adolescents and parents. The Critical Appraisal Skills Programme Qualitative Checklist was used to appraise the quality of the studies. Extracted data underwent inductive thematic analysis. Results: The synthesis, representing 990 people living with alopecia, identified five main themes, focusing on managing identity and appearance changes: (1) coming to terms with a changed identity; (2) the journey to acceptance; (3) complexities of concealing hair loss; (4) social influences in both facilitating and hindering adaptation; and (5) treatment experiences highlighting unmet needs. Findings reveal substantial variation in managing identity and appearance changes, with some individuals achieving acceptance swiftly while others struggle. Social reactions and personal interpretations significantly shape adjustment. Conclusions: Alopecia profoundly impacts identity, coping, and social interactions, often accompanied by dissatisfaction with health care and treatment options. The reactions of other people and interpretations of these experiences appear to play a key role in adjustment. The review underscores the need for personalized, non‐pharmacological interventions that address personal and social challenges. Greater co‐production in health care training and intervention development is necessary to improve support for individuals with appearance‐altering conditions
Subglacial topography of Coats Land records post-Gondwanan landscape evolution and early ice-sheet behaviour in East Antarctica
No full textThe East Antarctic Ice Sheet (EAIS) formed circa 34 million years ago and now contains an ice volume equivalent to ∼52 m of global sea-level rise. Although the EAIS is approximately in balance today, there is substantial uncertainty regarding the sensitivity of sectors underlain by low-lying bed topography to future climate and ocean warming. This is especially pertinent for Coats Land (eastern Weddell Sea), where geological records of past ice-sheet changes are sparse. Here, we use airborne radio-echo sounding and magnetic data, satellite imagery, and isostatic modeling to map the subglacial geomorphology of Coats Land for the first time and constrain the regional geological and ice-sheet history. Our mapping reveals topographic features such as tilted highlands and deep, asymmetric depressions, which likely formed via regional extension associated with Gondwana breakup, concomitant with early Jurassic magmatism. We also document low-relief, seaward-dipping surfaces that we infer to be remnants of coastal plains formed by fluvial erosion after continental breakup. Subglacial troughs that were incised into (i.e., post-date) these pre-glacial erosion surfaces were selectively eroded by ice flowing south-to-north. The ice within these troughs is stagnant today, indicating that they did not form beneath the modern (east-to-west-flowing) EAIS. Based on local geomorphological and geochronological evidence, we infer that these troughs were most likely incised during an interval of the Oligocene–Miocene (ca. 34–14 Ma) when the regional ice configuration and bed topography were significantly different from today. Subsequent EAIS reconfiguration switched off these early outlets and facilitated widespread landscape preservation beneath regionally non-erosive ice
Stretching and Compressing Capillary Bridges on Hydrophilic, Hydrophobic, and Liquid-Infused Surfaces
No full textAqueous capillary liquid bridges are ubiquitous in nature and in technological processes. Here, we comparatively investigate capillary bridges formed between three distinct types of surfaces: (i) hydrophilic glass, (ii) hydrophobic dichlorodimethylsilane (DMS)-functionalized glass, and (iii) liquid-infused (LIS). We combine experimental measurements and computer simulations of the capillary bridges’ evolution upon changes in the gap size between the surfaces, deriving in each case the bridge geometry and the resulting capillary force. The results, also compared with predictions from the existing theory, follow expected trends on glass and DMS-functionalized surfaces: contact line pinning dominates the bridge behavior on glass with a characteristic stick–slip motion, whereas a pronounced advancing and receding hysteresis is observed on DMS surfaces. On LIS, the absence of pinning leads to minimal force variation, gravity-driven breaking of the bridge symmetry, and possible liquid exchange between LIS through bridge cloaking. These effects become particularly significant in asymmetric bridge configurations combining LIS and DMS surfaces, where the transfer of lubricant from LIS to DMS modifies the effective surface tension and alters bridge–surface interactions. Our systematic comparison of the capillary bridge behavior across solid and liquid interfaces with varying wettability provides a foundation for designing functional surface applications with controlled bridge–surface interactions
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