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Haze optical depth in exoplanet atmospheres varies with rotation rate : implications for observations
Get PDFFunding: The authors acknowledge the funding and support provided by the Edinburgh Earth, Ecology, and Environmental Doctoral Training Partnership and the Natural Environment Research Council (grant No. NE/S007407/1).Transmission spectroscopy supports the presence of uncharacterized, light-scattering and -absorbing hazes in the atmospheres of many exoplanets. The complexity of factors influencing the formation, 3D transport, radiative impact, and removal of hazes makes it challenging to match theoretical models to the existing data. Our study simplifies these factors to focus on the interaction between planetary general circulation and haze distribution at the planetary limb. We use an intermediate-complexity general circulation model, ExoPlaSim, to simulate idealized organic haze particles as radiatively active tracers in the atmospheres of tidally locked terrestrial planets for 32 rotation rates. We find three distinct 3D spatial haze distributions, corresponding to three circulation regimes, each with a different haze profile at the limb. All regimes display significant terminator asymmetry. In our 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.Peer reviewe
Deep-red to NIR solution-processed OLEDs of donor-decorated quinoxaline-based TADF aggregates
Get PDFFunding: AKG is grateful to the Royal Society for a Newton International Fellowship NF171163. We acknowledge support from the Engineering and Physical Sciences Research Council of the UK (grants EP/W007517/1, EP/P010482/1, and EP/L017008/1). We are also grateful for financial support from the University of St Andrews Restarting Research and Restarting Interdisciplinary Research Funding Schemes (SARRF and SARIRF) which are funded through the Scottish Funding Council grant reference SFC/AN/08/020.We report the use of an extended π-conjugated electron-deficient “pyrazino[2,3-g]quinoxaline ( PQ )” as a strong, planar acceptor in a donor–acceptor thermally activated delayed fluorescence (TADF) emitter design to achieve deep-red to NIR emission. A pair of multi-donor–acceptor (multi-D–A) emitters, 4DMAC-TPPQ and 4PXZ-TPPQ , using PQ as the strong acceptor and dimethylacridine (DMAC) and phenoxazine (PXZ) as strong donors, respectively, emit at 650 and 762 nm in toluene, which is significantly red-shifted in comparison to the parent compound TPPQ (λPL = 456 nm). Both compounds show aggregation-induced emission enhancement in THF:water mixtures. Both compounds exhibit TADF as doped films in 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) and as neat films. The emission of the neat film is similar to that in toluene with λPL of 654 and 770 nm for 4DMAC-TPPQ and 4PXZ-TPPQ , respectively. Solution-processed organic light-emitting diodes (SP-OLEDs) of neat 4DMAC-TPPQ showed electroluminescence (λEL) at 685 nm and an EQEmax of 0.3%, while the device with 4PXZ-TPPQ emitted at an λEL of 780 nm and showed an EQEmax of 0.04%. The OLEDs with 4PXZ-TPPQ showed the most red-shifted emission amongst those employing TADF emitters containing a quinoxaline-type acceptor.Peer reviewe
Acoustic characteristics and context of buzzes and rasps produced by northern bottlenose whales (Hyperoodon ampullatus)
Get PDFFunding: Data were collected by the 3S and body condition projects, supported by US Office of Naval Research (ONR grants N00014-15-1-2533 and N00014-16-1-3059), US Strategic Environmental Research and Development Program (SERDP award RC-2337), the French Ministry of Defence (DGA) and the Netherlands Ministry of Defence. This project was further funded by a doctoral grant from the University of Iceland Research Fund, a postgraduate scholarship from the University of St Andrews’ School of Biology (both to CEH), and a Project Grant (no. 207081) from the Rannís Icelandic Research Fund (to PJW).Deep-diving northern bottlenose whales (Hyperoodon ampullatus) rely on sound for orientation, foraging and communication. While their regular echolocation clicks have been described, characterisations of other click types are limited. Here we quantify acoustic and behavioural differences between two types of rapid click trains: buzzes and rasps. Sound and movement data were collected from 15 animal-attached DTag deployments around Jan Mayen Island (Norway) from 2013–2016. Buzzes and rasps were manually identified, and random forest analyses revealed a classification accuracy of 93.7% (n = 129 respectively). Rasps occurred more often near the surface whereas buzzes were primarily emitted at depth during foraging dives, had shorter inter-click-intervals (U = 263, p < 0.001), longer durations (U = 14413, p < 0.001), and coincided with increased movement more often than rasps (U = 10384, p < 0.001). On-axis clicks from nearby whales showed further differences in duration and frequency content between individual buzz and rasp clicks. Our findings demonstrate that buzzes and rasps are acoustically and contextually distinct, with buzzes associated with foraging and rasps with communication. These differences will allow identification of buzzes and rasps and inference of behaviour and habitat use in passive acoustic data, enhancing research on this cryptic beaked whale.Peer reviewe
Sensitivity of endogenous autofluorescence in HeLa cells to the application of external magnetic fields
Get PDFFunding: This work was supported by Operational Programme Research, Development and Education financed by European Structural and Investment Funds and the Czech Ministry of Education, Youth and Sports (Project No. SOLID21—CZ.02.1.01/0.0/0.0/16_019/0000760) and MH CZ—DRO Institute for Clinical and Experimental Medicine—IKEM, IN 00023001. G.J.S. was partly supported by the Research Council of Norway through its Centres of Excellence funding scheme (project number 262613).Dramatically increased levels of electromagnetic radiation in the environment have raised concerns over the potential health hazards of electromagnetic fields. Various biological effects of magnetic fields have been proposed. Despite decades of intensive research, the molecular mechanisms procuring cellular responses remain largely unknown. The current literature is conflicting with regards to evidence that magnetic fields affect functionality directly at the cellular level. Therefore, a search for potential direct cellular effects of magnetic fields represents a cornerstone that may propose an explanation for potential health hazards associated with magnetic fields. It has been proposed that autofluorescence of HeLa cells is magnetic field sensitive, relying on single-cell imaging kinetic measurements. Here, we investigate the magnetic field sensitivity of an endogenous autofluorescence in HeLa cells. Under the experimental conditions used, magnetic field sensitivity of an endogenous autofluorescence was not observed in HeLa cells. We present a number of arguments indicating why this is the case in the analysis of magnetic field effects based on the imaging of cellular autofluorescence decay. Our work indicates that new methods are required to elucidate the effects of magnetic fields at the cellular level.Peer reviewe
Detecting spatial heterogeneity in the determinants of intercity migration in China
Get PDFFunding: This work has received support from CUHK Vice-Chancellor's PhD Scholarship and CUHK Research Committee Research Fellowship Scheme.Spatial variations exist in migration patterns and the processes causing the observed patterns. Yet, far less attention has been given to the latter. Even if a few studies have engaged in spatial heterogeneity in the process of migration, the scale multiplicity is not emphasised. This research aims to address these gaps with evidence from Chinese cities. To facilitate international comparisons, we use data on intercity migration over a 5-year interval instead of the floating population. Following an elaboration of highly imbalanced migration patterns at the city scale, we detect spatial heterogeneity in the processes underlying these patterns based on 17 potential determinants in four domains (namely labour market conditions, site-specific amenities, agglomerative effects, and institutional dividends) by multiscale geographically weighted regression. The results indicate that cities' attractiveness to migrants depends on a broad spectrum of factors whose influences are location-dependent and exhibit specific patterns, including east–west, south–north, and southwest–northeast gradient patterns, as well as discrete clustered and concentric patterns. The diagnostic analysis has confirmed that the provenance of spatial-varying effects is irrelevant to the nonlinearity. These effects are also scale-sensitive, showing that the influencing scales of the labour market status and agglomeration factors tend to be larger (i.e., their effects are spatially stationary) than those relevant to amenities and policies, which vary considerably (i.e., the impacts of some factors change significantly over space). These findings regarding spatial heterogeneity deepen our understanding of migration in China and highlight the fact that there is no ‘one size fits all’ approach for government policies designed to attract migrants.Peer reviewe
Using spatial capture-recapture methods to estimate long-term spatiotemporal variation of a wide-ranging marine species
Get PDFFunding: Funding support was provided by NOAA under multiple grants and contracts for both the work that generated the data and the analysis.Determining population status to inform mitigation of anthropogenic threats requires statistical approaches that investigate spatial and temporal variation. In the face of climate change it is increasingly important to differentiate between changes in population size and redistributions of populations. This is especially true for wide-ranging species such as the blue whale. Abundance of eastern North Pacific blue whales has previously been estimated using (non-spatial) closed capture–recapture and distance sampling methods, but the estimates show opposite and diverging trends over the last 30 years. Evidence that the distribution has been expanding could explain the apparent disparity, due to the confounding effects of spatial variation in sampling and the changing distribution. To investigate this, we apply, for the first time, spatial capture–recapture (SCR) methods to blue whale photo-identification data from small boat surveys to estimate abundance. The study area was defined as the length of the continental USA coastline, extending approximately 100 km offshore. Average annual effort from 1991 to 2023 was 97 days, resulting in 7358 sightings of 1488 unique individuals. We find significant support for non-linear spatiotemporal variation. In all years, there were higher densities at lower latitudes but there were notable decadal cyclical fluctuations in the number of animals using the study area. This large variation in the numbers of animals using these waters motivates further study into the relationship with environmental changes. Our results are an important step in spatially explicit modelling of observational blue whale data, which highlight the value of including spatial and temporal data and are relevant to any marine mammal species monitored using photo-identification.Peer reviewe
Sienese art and global encounters, 1300-1492
No full textThis dissertation examines the representation of otherness in Sienese art, tracing the city's evolving perceptions of human difference across the fourteenth and fifteenth centuries. During this period, marked by unprecedented cross-cultural exchanges and expanding geographical awareness, Latin Christendom came into direct contact with populations previously unknown or only imagined through classical and biblical texts. Within this framework, I take Siena as the focal point through which to investigate Western relations with the Mongol Empire during the fourteenth century and with Sub-Saharan Africans in the fifteenth. Siena presents a paradox: despite its landlocked location, lack of direct waterways, and long-standing historiographical reputation for artistic insularity and introspectiveness, the city produced a remarkably rich visual record of 'racial' diversity, unique for its variety, volume and detail. For example, Ambrogio Lorenzetti's Martyrdom of the Franciscans is considered amongst the most meticulous Western depictions of Mongol appearance, while Nicola Pisano's pulpit for Siena cathedral includes the earliest known representation of Black Africans in the iconography of the Adoration of the Magi. Offering an alternative to global art historical narratives that have treated these Sienese examples as isolated anomalies or focused on well-documented international city-states like Venice and Florence, this dissertation proposes a new interpretative approach to Sienese art as a cohesive whole. By examining the city's artistic production across a range of media from 1300 to 1492, it unravels how notions of difference were constructed in Siena prior to the Atlantic slave trade, the rise of European nationalism and early modern essentialists categorisation of 'race.' It argues that Siena's artistic selfhood developed through a fluid exchange with people and objects originating from beyond the Western sphere, ultimately challenging traditional art historical views of a ‘home-grown’ Sienese Renaissance arising as an exclusively Western phenomenon."The Scottish Graduate School for Arts and Humanities deserves the first mention in these acknowledgments, for without their support, this dissertation would have remained little more than a lofty idea. Their generous funding programme (SGSAH AHRC Doctoral Training Partnership) not only made this project possible but also connected me to a network of dedicated people and valuable resources. Alongside the Department of Art History at St Andrews, they welcomed me into the vibrant academic community of Scotland, making me feel truly at home."--Acknowledgment
Pets as humans and humans as pets in imperial Rome
Get PDFPet keeping in Rome was a cultural and class-based phenomenon to which modern expectations about the role of the pet are not easily applicable; in particular, any conceptualisation of pet ownership in imperial Roman society must be complicated by the existence of human pets, the so-called pueri minuti. A consideration of the role of the pet child brings into clearer focus some of the underlying structures of the pet-owner relationship as experienced at Rome: the one-sided nature of the affection demonstrated, the owner’s indifference to the pet’s interior state, and the permeable conceptual boundary between the animal and the human.Peer reviewe
On distributional limit laws for recurrence
Get PDFFunding: MT was partially supported by the FCT (Fundaçao para a Ciencia e a Tecnologia) Project 2022.07167.PTDC. MH acknowledges University of St Andrews for hospitality. Both authors gratefully acknowledge LMS Scheme 4 fundingFor a probability measure preserving dynamical system (,f,µ), the Poincaré Recurrence theorem asserts that µ-almost every orbit is recurrent with respect to its initial condition. This motivates study of the statistics of the process Xn(x) = d(fn(x), x)), and real-valued functions thereof. For a wide class of non-uniformly expanding dynamical systems, we show that the time-n counting process Rn(x) associated to the number recurrences below a certain radii sequence rn(τ) follows an averaged Poisson distribution G(τ). Furthermore, we obtain quantitative results on almost sure rates for the recurrence statistics of the process Xn.Peer reviewe
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