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Algal reorganization in post-crisis early Triassic oceans revealed by biomarker evidence
Get PDFThe end-Permian mass extinction (EPME) fundamentally reshaped marine ecosystems. However, the long-term response of eukaryotic algae, a key foundation for marine primary production, is poorly understood. To address this limited knowledge, we determine the long-term change in algal communities using molecular fossil steranes. We use samples that span the uppermost Permian to the Lower Triassic from sections that were located in Boreal Sea (Sverdrup Basin, Arctic Canada) as well as the tropical Tethys (Xiakou, South China), and complement these new data with published datasets. Sterane to hopane ratios, reflecting the relative contribution of eukaryotic algal to bacterial sources, vary in absolute values between sites but show no significant decrease in the earliest Griesbachian compared to the pre-crisis Permian. However, Early Triassic ratios changed dramatically. In the Sverdrup Basin, they were stable during the Griesbachian and, following an interval where both hopane and sterane concentrations diminished, became much higher in the late Spathian. This confirms suggestions that there was a major decline in algal productivity after the EPME that may have delayed recovery. Sterane C28/C29 ratios, which monitor algal composition, increase at the EPME level in Meishan and are generally higher in the rest of the Early Triassic in the Sverdrup Basin and Chaohu. The increase shows that algae that preferentially produce C28 over C29 sterols were thriving, possibly including those predominant in modern oceans. It further implies a reorganized marine algal community–apparently in the tropics and in the post-crisis interval in the Boreal realm. Our findings suggest that instead of a simple collapse and recovery, the Early Triassic saw a complicated reorganisation for algae
Analysis and quantification of the propensity of hair dyes to desorb from human hair fibre using an accelerated 48-wash method
Get PDFThe durability of oxidative hair dyes is a critical factor in consumer satisfaction and hair colour product development. This study introduces an accelerated 48-wash analytical method for quantifying hair dye desorption, combining spectrophotometric colour strength measurements with a back-extraction protocol coupled to HPLC. The approach was first validated using a two-component model dye system comprising p-aminophenol and 2-methyl-5-aminophenol, forming a heterodimeric product that could be quantitatively monitored. Hair types studied included Natural White Hair and Bleached Blonde Hair, with dyeing performed using either ammonia or monoethanolamine as the alkalizing agent. Results demonstrate that most colour loss occurs during the first wash, and Bleached Blonde Hair treated with monoethanolamine exhibits the highest dye desorption, reflecting superficial dye deposition and structural vulnerability of chemically processed hair. In contrast, ammonia-based formulations promote deeper dye penetration and improved retention. Colour loss trends quantified by spectrophotometric measurement followed a logarithmic pattern over the accelerated 48 wash test, and strong correlations (R2 > 0.95) were observed between spectrophotometric data and HPLC quantification of dye removal. The robustness of the method was also demonstrated on multi-component dye formulations, and although direct HPLC quantification was challenging for these more complex systems, the spectrophotometric measures serve as a reliable proxy for quantification of actual dye loss, based on the calibration established with the model two-component system. This work provides a quantitative framework for understanding hair dye wash fastness, the influence of hair type and alkaliser, and the mechanisms of dye desorption. The method supports future product innovation by linking molecular-level dye behaviour to long-term colour performance
Using theories of power and place to evaluate community health promotion
Get PDFThere is some consensus that better ways of evaluating complex public health programmes are needed as experimental methods are limited in explaining the 'how' and 'why' of change. Methods like 'theory-of-change,' 'realist evaluation,' and 'systems evaluation' try to give a more complete picture of change by looking at the context of the programme. However, when these methods are used to study programmes that aim to reduce health inequalities, they often miss a crucial issue: how power affects people's health and engagement with programmes. This paper addresses that gap by reporting an ethnographic study of a community health promotion programme that was informed by a social theory of power (figurational sociology). When looking at how power dynamics played out in the targeted community, we could see why residents often did not trust the people running the programme, and why local status was so important to them. When programme staff understood these power dynamics, they were better able to connect with residents and help them improve their wellbeing. We argue that combining this way of looking at power with our observational approach gives us a much clearer understanding of how complex public health programmes work and why they succeed or fail in their aims
What about the delta (ẟ13C)? A case for brackish fish in Mediterranean palaeodietary isotopic baselines
Get PDFWhile a lot of paleodietary studies in the Mediterranean region have reported ẟ13C and ẟ15N values for humans, similar data for aquatic resources is much more limited. The aim of our paper is to make relevant data available for isotopic faunal baselines and future paleodietary research in the eastern Mediterranean. We analysed the collagen extracted from the bones of freshwater and brackish fish from two coastal archaeological sites in the Levant, Kinet Höyük (n = 21) (1550 BCE − 14th c. AD, present day Turkey) and Tell el-Burak (n = 8) (975–332 BCE, present day Lebanon). From the original 29 bones sampled, 17 (59 %) produced collagen which met quality control criteria and we present the corresponding ẟ13C and ẟ15N values here. Whereas freshwater and marine ecosystems in an area typically have distinctive ẟ13C values, paleodietary interpretations regarding aquatic resource consumption can be challenging when isotopic values reflecting the range of exploitable aquatic environments are not available. Bearing this in mind, our data set is used to demonstrate the potential range of ẟ13C values (−27.97 ‰ to −10.87 ‰) of freshwater and brackish environments along the Levantine coast, encouraging future palaeodietary studies in the region to consider this more robust isoscape for aquatic resources
Extreme weather and corporate fixed asset policies: leasing as alternative finance
Get PDFThis paper investigates how weather-affected firms make decisions on fixed asset purchases and financing choices for fixed asset acquisition. Utilizing a unique dataset comprising over 26,000 firms across 40 countries, we find that weather-affected firms are more prone to purchase fixed assets, increasing investments in machinery, equipment, and real estate. These purchases are primarily financed through equity, bank loans, and government grants. Particularly, we find that leasing is a vital fallback financing source for firms experiencing losses due to extreme weather. Firms that exclusively rely on leasing rather than other financial sources are more likely to face significant external financing barriers, including complex loan procedures, high collateral requirements, and increased loan rejection rates. Interestingly, weather-affected firms that have successfully obtained non-leasing finance for fixed asset purchases have a higher tendency to also engage in leasing, highlighting that such firms adopt flexible strategies for fixed asset acquisition
Estimation of Common Factors for Microstructure Noise and Efficient Price in a High-frequency Dual Factor Model
No full textConceptualising coercion in child/forced marriage through an intersectional lens: Narratives of survivors and practitioners in the US
Get PDFThis article examines the nature and the forms of coercion in the forced marriage of minors in the United States. We explore: (i) direct emotional or physical force exercised by parents which is commonly underpinned by dominant constructions of gender and sexuality, a well-rehearsed theme in existing scholarship; (ii) the hitherto unexamined role of intersecting socio-economic disadvantages in vitiating consent; and (iii) how state policies/practices create conducive contexts for child/forced marriage, which is elided in existing scholarship. In extending existing conceptualisations of coercion in child/forced marriage, we explicate the ‘total burden of coercion’ through a focus on the contexts within which consent is constructed at the intersection of social relations of power based on gender, age, race/ethnicity, poverty, sexuality, and state policy/practice. Our analysis also illuminates the complex nature of survivors’ girlhood decision-making in the face of coercive constraints within which their agential capacities are formulated and exercised, and risk negotiated and managed
Sub-optimal internal mammary grafts: incidence, timing, and etiology
No full textThe left internal mammary (thoracic) artery (LIMA), when used as a pedicle graft at the time of coronary artery bypass grafting, is effective and durable. Data concerning the rate and causes of LIMA failure are scant. The aim of this paper is to explore the modes and frequency of sub-optimal LIMA grafts. We examined all cases of invasive graft angiography performed in our cardiothoracic center 2016–2020 and analyzed the quality of the LIMA graft. Of 551 cases, 323 had undergone isolated coronary artery bypass grafting including a LIMA since 2001; of those, 59 (18%) appeared sub-optimal; 16 (5%) being totally occluded, 26 (8%) exhibiting a “string sign” (i.e., atretic or cord-like), 12 (4%) being focally stenosed, and 5 (1.5%) being patent but placed on a diseased portion of the left anterior descending artery or other vessel. The commonest cause of failure were poor-quality left anterior descending artery target and non-flow-limiting disease. This paper highlights the low rate, and likely modes, of failure of this valuable treatment in contemporary practice
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