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Definition of important factors in polarised infrared spectroscopy: vibrational circular and linear dichroism in normal transmission mode and in attenuated total reflectance
No full textInfrared absorbance (IR) spectroscopy is seeing a resurgence in applications in both quality control and research laboratories. Vibrational linear dichroism (VLD) adds a dimension to the spectrum for oriented samples, which helps separate peaks and identify polarisations of transitions. Measuring VLD by rotating either the sample or a polariser is prone to error, so we use an adapted vibrational circular dichroism (VCD) instrument with a photoelastic modulator producing alternate polarisations to measure VLD. However, in contrast to VCD, transmission VLD spectra show a small contribution to the VLD that follows the absorbance even for isotropic samples. In this work, we show the origin of this contribution to VLD and why it does not affect VCD. This leads to a method for extracting the true VLD spectra from the measured data. In an attenuated total reflectance (ATR) mode of measurement, the situation is further complicated by the polarisation and refractive index-dependent changes of the light's electric field intensity. Equations are developed to account for these effects. It appears that there is a variable contribution of an absorbance spectrum to the ATR-VLD. Some speculation is given as to the origin of this effect.The authors are extremely grateful for the helpful feedback from the reviewers.Peer-reviewe
Quantitative Geographic Analysis: A Cultural History of Australian Bushfire Narratives
No full textIn colonial Australia, newspapers frequently published serialised fiction and journalistic accounts of bushfires side by side. Across the 19th century, fictional depictions of settler endurance and survival were increasingly tempered by journalistic portrayals of destruction. By the century's end, these narratives framed fire as a force that overcame social divisions, unifying settlers in a collective struggle against nature that exemplified the distinctively nationalistic value of "mateship." At least, that is how the story has been told...
In Australian literary studies, such nationalist narratives have been the subject of growing critique for their narrow and exclusionary constructions of Australian identity, highlighting the need for a critical reassessment of cultural representations of bushfires and their associated national values. This task, however, is complicated by the limited historical research on 19th-century bushfires. While major fire disasters such as Black Thursday (1851) and Red Tuesday (1898) have received some scholarly attention, the intervening years remain largely unexplored. This thesis addresses this gap, employing computational techniques to extract, geolocate, and map geographic information about historic Australian bushfires from 19th-century journalism and serialised fiction. Reading fiction in dialogue with bushfire reporting offers a critical lens through which to examine the cultural values and beliefs associated with fire, shedding light on evolving perceptions of colonial disaster and the ways in which Australian bushfires have been mythologised, commemorated, or forgotten.
This thesis not only offers insights into the spatial dimensions of colonial Australian writing but also critically examines the role of digital mapping technologies in literary analysis. While these technologies are often presented as transformative tools, discourses of technological novelty tend to obscure the need for a more critical engagement with how they both enable and constrain scholarship. Adopting an affordance-based heuristic framework, this study foregrounds two under-theorised technologies that underpin digital mapping practices-Named Entity Recognition (NER) and geocoding algorithms (GAs)-to explore how they actively shape knowledge production. This perspective challenges reductive cartographic approaches that treat literature as a direct representation of geographic space, instead advancing an alternative position that frames literary realism as a record of environmental decline. Drawing on a corpus of over 42,754 newspaper articles and 247 serialised novels and short stories, this extended fire history compels a reconsideration of historical bushfires as "disasters," demonstrating how colonial journalism and fiction documented and responded to ecological transformations throughout the 19th century
Do environmental fluctuations during development affect trait variation? An experimental test with salinity
No full textHuman-induced climate change is a driver of extinction, with extreme events occurring more frequently. It increases both the amount and fluctuations in environmental stress that organisms experience. In such environments, greater intra-specific trait variation creates more potential for adaptation through natural selection. Many studies focus on changes in trait means between novel and historic environments but overlook changes in trait variation. Here we tested how salinisation – which currently affects 20–50% of freshwaters worldwide – alters trait variation in a freshwater fish, Gambusia holbrooki. We reared newborn fish in freshwater, stable-salinity or fluctuating-salinity water until maturation, and then compared variation in fitness-related traits in each sex during early and late adulthood. Salinisation had stronger effects on young virgin adults than older mated adults, with sex-specific impacts (female: gut development; male: age at maturity and body size). When we accounted for the mean trait value in each environment, salinisation also affected relative variation (i.e. the coefficient of variation) in female fecundity (egg size, offspring number). Notably, the fluctuating-salinity treatment did not magnify the effect of the stable-salinity treatment on trait variation but sometimes reversed its effect. Our findings suggest that researchers should pay closer attention to fluctuating environmental stressors, as they can differ from stable stressors in how they affect between-individual variation in trait expression.Our research was supported by the Australian Research Council (DP190100279: MDJ; DP210101152: DWAN).Peer-reviewe
The Effect of Sharp Bends and Cable Coupling on DAS Recording in an Urban Environment
No full textDistributed acoustic sensing (DAS) records represent the strain (rate) in an optical fiber averaged over a gauge length about a specified channel. In the presence of bends and variable coupling to the surroundings, the effect of gauge-length averaging is more complex than for a straight cable. Analysis for an incident plane wavefront shows how both changes in cable orientation and coupling can produce significant changes in signal amplitude in the immediate neighborhood of the change. Coupling effects can be distinguished by the strong correlation of P and S behavior because orientation factors differ for the two wavetypes. Such effects are illustrated with DAS records from an urban cable in Perth, Western Australia, with cable segments along nearly orthogonal streets in a grid pattern and also long cable loops with poor ground coupling.Peer-reviewe
Palaeoecological studies at four archaeological sites in the New Guinea Highlands document local vegetation histories and plant use from c. 18,000 cal BP to the recent past
No full textPlant microfossils at archaeological sites in the New Guinea Highlands have received little attention compared to lithic and faunal analyses. Here we analyse plant microfossils (pollen, charcoal particles, phytoliths, and starch) from three rockshelters (Yuku, Kiowa, and Manim) and one open site (Wañelek), dating from c. 18,000 cal BP. Pollen results show a diverse range of taxa, and record major as well as subtle changes in vegetation history, with complimentary phytolith results. Vegetation changes, especially Nothofagus spp. decline, were driven by post-LGM climatic warming and anthropogenic deforestation, respectively, yielding mixed Castanopsis-Lithocarpus lower montane forest, and secondary forest, disturbance taxa, and grasslands. Low charcoal counts and ground fern establishment suggest periods of limited use within some rockshelters. Subsistence plant remains include starch of cf. Castanopsis acuminatissima nuts and cf. Colocasia esculenta corms, and a leaf phytolith of Musa sp. A new type of aquatic archaeological marker, cf. euglenoid cysts, was also identified.We acknowledge funding through ARC grants DP0666524 and FT150100420 to TD.Peer-reviewe
Anthropogenic warming is accelerating recent heatwaves in Africa
No full textClimate change is intensifying extreme events worldwide, with Africa emerging as a uniquely vulnerable hotspot where heatwaves increasingly threaten populations and ecosystems. This study quantifies the roles of anthropogenic aerosols, greenhouse gases, and internal variability in trends of daytime, nighttime, and compound heatwaves. Using the Community Earth System Model 2—Large Ensemble, we examine two distinct periods: 1950–1979, with relatively stable temperatures due to aerosol-induced cooling offsetting greenhouse gas warming, and 1985–2014, marked by rapid warming. During 1950–1979, heatwave trends were weak and non-robust, with internal variability explaining over 80% of the variability. In contrast, 1985–2014 saw strong increases in heatwave frequency, duration, and intensity (>0.15 heatwaves season−1 decade−1, >0.3 days season−1 decade−1, >0.3 °C season−1 decade−1, respectively), largely driven by greenhouse gases, with internal variability’s role declining to ~30%. This recent intensification is primarily modulated by enhanced clear-sky longwave radiation, anticyclonic circulation, and increased atmospheric moisture.Peer-reviewe
Visualising and quantifying Mg/Ca and Sr/Ca heterogeneity in the isochronous growth increments of bivalve shells (Tridacna)
No full textUltra-high (hourly to daily) and high (annual) resolution paleoenvironmental proxies derived from geological and archaeological sclerochronology archives provide us with a window into ancient times. As one of the most common and well-developed archives, bivalve shells play a very important role in reconstructing past environments and connecting palaeo-environmental records with past human behaviours. However, we still lack a basic understanding of whether bivalve shells have evenly distributed trace element abundances in shell portions that grew at the same time (i.e., isochronous growth increments). In this study, we present the first published application of laser-induced breakdown spectroscopy (LIBS) for qualitative two-dimensional elemental mapping of Tridacna shells. To complement the qualitative results, we also employed laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and wet-chemistry trace element analyses to acquire quantitative composition of Mg/Ca and Sr/Ca in Tridacna maxima shells, addressing the question of spatial heterogeneity in shell geochemistry. Our results reveal significant spatial heterogeneity in Mg/Ca and Sr/Ca ratios within contemporaneous increments, which could lead to a ± 4.3 to 5.5 °C variance in palaeo sea surface temperature reconstructions. This heterogeneous distribution may result from varying environmental exposure in different areas of a shell influencing the sensitivity and efficiency of minor and trace element incorporation in the different regions of the shell's epithelium tissue. By better understanding the natural heterogeneity of trace element uptake across isochronous growth increments, this study makes a fundamental step forward in assessing the reliability of sea surface temperature reconstructions and guiding future data acquisition strategies.Bohao Dong was supported by the Melbourne Research Scholarship from the University of Melbourne and a Postgraduate Research Award (PGRA) (ALNSTU12820) from the Australian Institute of Nuclear Science and Engineering (AINSE) Ltd. Amy Prendergast was supported by an Australian Research Council DECRA Fellowship (DE200100890) and by the Australian Research Council Centre of Excellence for Indigenous and Environmental Histories and Futures (230100009CE). Niklas Hausmann was supported by the German Research Foundation under the Emmy Noether Program (project number: 439799406).Peer-reviewe
First principle investigation of the structural, elastic, optoelectronics, and thermodynamic properties of barium-based tetragonal complex perovskite hydrides X<sub>2</sub>BaH<sub>4</sub> (X= Na, K, and Rb) for hydrogen storage applications
No full textThis study utilizes density functional theory (DFT) to explore the structural, hydrogen storage capacity, optical, electronic, and thermo-physical properties of complex metal hydrides X2BaH4 (X = Na, K, and Rb) for potential hydrogen storage applications. All compounds possess a stable tetragonal structure and space group 14/mmm. Their dynamic stability is confirmed by positive frequency values of phonon dispersion curves. The compounds satisfy the Born–Huang stability criteria, confirming their dynamic and mechanical stability. Electronic properties evaluation by hybrid HSE06 functional calculations reveals the insulating behavior of these materials, with band gaps of 1.52 eV for Na2BaH4, 3.00 eV for K2BaH4, and 2.24 eV for Rb2BaH4. This insulation character prevents electrical interference during hydrogen absorption and desorption. Na2BaH4 possesses the highest hydrogen storage capacity (2.10 wt%). The optical study gives insights into light and matter interactions, relevant to energy applications for these materials. These results highlight X2BaH4 perovskite hydrides as stable and potential materials for efficient hydrogen storage technologies.This research is supported by the Higher Education Commission of Pakistan via NRPU project No: Ref No. 20–15798/NRPU/R&D/HEC/2021-2020.Peer-reviewe
‘He Does Not Speak of Civilizing the Australians Now’: Matthew Moorhouse, Craniology, and Aboriginal Protection in South Australia, 1839–65
No full textMatthew Moorhouse was Protector of Aborigines in the colony of South Australia from 1839 to 1856. He has been the subject of research by many scholars interested in the history of race relations and protective governance in early colonial Australia and is typically considered to have been one of the more sympathetic and dedicated officers to have served in the role of protector. A lesser-known aspect of his career is his collection of Aboriginal ancestral remains, including several skulls and two full skeletons, which he sent to a prominent craniologist in Britain. This article examines his career in light of these collecting activities, and argues that race science, specifically craniology and phrenology, provided for Moorhouse a rationale for abandoning the more ambitious aims of the early Aboriginal protectorates.Peer-reviewe
