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Masculine hierarchies in migrant homosocial workspaces : dominating and subordinating masculinities of Tajik labor migrants in Russia
Get PDFThis article analyzes how masculinity practices transform in homosocial workspaces of labour migrants. Drawing on extensive fieldwork in Russia and Tajikistan, the article scrutinises the experiences of Tajik migrant men who work in the largely informal construction sector in Russia. Their interactions are thus embedded in this country’s capitalist system, as well as its migration and labour regimes which are characterised by irregularity and discrimination. It is argued that work relations and hierarchies emerging between migrant men in receiving countries are shaped, on the one hand, by cultural ideas of masculinity and social norms from sending communities and, on the other, by neoliberal forms of precarity. They both contribute to creating new power dynamics, including work-related masculine practices. The article analyzes the process of how two masculinity types emerge which are situational and complementary to each other. The first is dominating masculinity which refers to practices of commanding people, in this case other migrant workers. The second is subordinating masculinity, a concept that we advance to capture the perceptions and practices of migrant men who temporarily accept the authority of other migrant men, such as intermediaries who are informally in charge of workers.Peer reviewe
Perspectives for best practices in boron-based CO2 reconstruction
Get PDFFunding: This work was supported through the ERC StG: 101040461 to TBC, NERC-NSFGEO C-FORCE NE/W009625/1 to TLB, UKRI Frontier Research Grant EP/X025918/1 to MJH, Leverhulme Trust Early Career Fellowship (ECF-2023-199) to HJ, and DFG: 467590255, and ERC CoG: 101125914 to EA.Since atmospheric carbon dioxide (CO2) is a key driver of global temperatures over geological time, determining past CO2 and fluxes among Earth's carbon reservoirs is critical in resolving drivers and feedbacks within Earth's climate system. Such CO2 reconstructions are challenging prior to ice core records of the last 800 kyrs, and yet it is beyond this time where the most promising analogs for our warmer, higher CO2 future lie. Amongst proxies for past CO2 reconstruction, boron isotopes (δ11B, primarily measured in foraminiferal carbonate) have become one of the most well-established, having demonstrated their ability to replicate atmospheric CO2 during periods where ice core estimates are available for comparison. Although analytical reproducibility across laboratories has greatly improved in recent years, the approaches taken to derive CO2 estimates from these boron isotope measurements remain variable. For example, there are significant inconsistencies in how seawater temperature, boron isotope, and elemental composition are estimated, in how a second carbonate system parameter is used to constrain the carbonate system, in how ecophysiological imprints on proxy signals are accounted for, and in how uncertainties are quantified and propagated. The need to better harmonize practices in the community motivated a series of virtual workshops and a PAGES-supported meeting, and ultimately this AGU Special Collection “Advances and Best Practices in Boron-based Paleo-CO2 Reconstruction.” In this synthesis article, we briefly summarize the history of approaches to address these issues, current limitations and strengths of the proxy, and highlight some important points to consider when applying the boron isotope proxy.Peer reviewe
On variants of the Furstenberg set problem
Get PDFFunding: The author was financially supported by an EPSRC Standard Grant (EP/Y029550/1) and a Leverhulme Trust Research Project Grant (RPG-2023-281).Given an integer d ≥ 2, s ∈ (0, 1], and t ∈ [0, 2(d − 1)], suppose a set X in ℝd has the following property: there is a collection of lines of packing dimension t such that every line from the collection intersects X in a set of packing dimension at least s. We show that such sets must have packing dimension at least max{s, t/2} and that this bound is sharp. In particular, the special case d = 2 solves a variant of the Furstenberg set problem for packing dimension. We also solve the upper and lower box dimension variants of the problem. In both of these cases the sharp threshold is max{s, t + 1 − d}.Peer reviewe
The magic of semi-perfluorinated mixtures : engineering MR-TADF emission from host–guest mixtures of liquid crystals
Get PDFFunding: Generous financial support by the Studienstiftung des deutschen Volkes (PhD fellowship for J. A. K.), the Ministerium für Wissenschaft, Forschung und Kunst des Landes Baden Württemberg, the Carl Schneider Stiftung Aalen (shared instrumentation grant), the Universität Stuttgart (Global glimpse travel grant for J. A. K.) and the DFG (INST 41/897-1 FUGG for 700 MHz-NMR, INST 41/1136-1 FUGG for LC-Orbitrap-MS: Exactive Plus Orbitrap MS System and INST 41/1135-1 FUGG for GC-Orbitrap-MS: Exactive GC Orbitrap MS System) are gratefully acknowledged. The St Andrews team would also like to thank EPSRC (EP/Z535291/1, EP/W007517/1, and EP/W015137/1) for financial support.Two liquid crystalline emitter–host mixtures have been developed, where each of the emitter and host self-assembles into a columnar hexagonal (Colh) mesophase, as does the mixture. The emitter consists of a modified 7-(tert-butyl)-5-oxa-8b-aza-15b-bora-benzo[a]naphtho[1,2,3-hi]-aceanthrylene B–O–Cz multi-resonant thermally activated delayed fluorescence (MR-TADF) core containing lateral semiperfluorinated side chains, while the host is derived from a modified MR-TADF 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene (DOBNA) core that also contains lateral semiperfluorinated side chains. Unlike the previously used alkoxy side chains in TADF liquid crystalline materials, the semiperfluorinated side chains only minimally perturb the optoelectronic properties of the luminescent cores, this despite the strong aggregation within the ordered columnar hexagonal (Colho) phase. This was achieved by shielding the emitter moieties from each other within the host mesophase, which mitigates excimer emission from aggregates and by engineering an efficient Förster resonance energy transfer from the host material to the emitter in the blend.Peer reviewe
Deracemisation of alcohols via simultaneous photocatalysis and whole-cell biocatalysis
No full textThis thesis outlines the research conducted on the application of concurrent stereoablative photobiocatalytic cascades and kinetic modelling on the deracemisation of secondary benzylic alcohols.
Chapter 1 introduces the motivation and fundamental concepts underlying this work, focusing on the benefits of photobiocatalysis, the mutual incompatibility within such dual catalytic systems, a literature review on the means for their co-adoption, and the modes of enantioconvergent catalysis this could enable.
Chapter 2 discusses the history and adaptation of a photocatalytic procedure for the oxidation of benzylic alcohols. Biocompatible media conditions were discovered to enable this facile transformation using sodium anthraquinone 2-sulfonate as a widely available, environmentally friendly, and water-soluble photocatalyst. Mechanistic studies supported the literature model for the photocatalytic cycle in addition to uncovering the significant degradation of the photocatalyst under our reaction conditions and the role of its two-electron reduced form as an electron sink under oxygen-limited conditions.
Chapter 3 details the generation and screening of a library of whole-cell biocatalysts expressing alcohol dehydrogenases for the asymmetric reduction of benzylic ketones, followed by reaction optimisation. Biocatalysts with Prelog- or anti-Prelog selectivity with coupled substrate cofactor regeneration were identified.
Chapter 4 discloses the construction of a concurrent linear photobiocatalytic cascade. Through extensive optimisation, a methodology for the deracemisation of secondary benzylic alcohols was developed, yielding significant improvements in efficiency and operational simplicity compared to previous reports. Trends and limitations in the substrate scope were discussed in terms of electronic properties and specific interactions with the biocatalyst.
Chapter 5 explores the application of kinetic modelling to extract additional information from time course datasets for deracemisation. Using the developed model, strategies for further reaction optimisation were preliminarily examined.
Chapter 6 summarises the outcome of the research presented herein and identifies promising directions for future work on concurrent photobiocatalytic linear deracemisation."This work was supported by the UKRI Biotechnology and Biological Sciences Research Council (BBSRC) Grant number: BB/M010996/1 via an EASTBIO Doctoral Training Partnership studentship and the Royal Society (University Research Fellowship URF\R1\180017, URF\R\231016, and associated Enhancement Award RGF\EA\181022)."--Fundin
Modified vegetable oils as potential lubricants
Get PDFAn account is given of the history of lubricant development and the important synthetic lubricant classes are described.
A range of polyol esters of straight chain fatty acids have been prepared and characterised. These include the 2,2 bis(hydroxymethyl) 1,3 propanediol esters of ethanoic, hexanoic, heptanoic, octanoic, nonanoic, decanoic and dodecanoic acids and the 2 ethyl 2 hydroxymethyl 1,3 propanediol esters of octanoic, nonanoic, decanoic and dodecanoic acids. Tabulated ¹³C and ¹H NMR data for these compounds are presented.
Some branched chain fatty esters have been prepared. Methyl 12 methyl-octadecanoate was synthesised from methyl ricinoleate. Methyl 9,12 dimethyloctadecanoate was prepared from the same starting material via the 9,12 diketone. An attempt to prepare methyl 9,10 dimethyloctadecanoate from methyl oleate via the 9,10 diketone was unsuccessful.
The preparation of arylated fatty esters was investigated. Initial work was done on the Friedel Crafts reaction of C₆ olefins with benzene and toluene. The products were investigated by GCMS and NMR. A range of mono , di and tri alkylated benzenes were detected.
The products of the reaction between methyl oleate and toluene were separated by TLC and investigated by NMR and MS. Depending on reaction conditions, 3 types of product are observed:- i) a 1/1 oleate/toluene adduct where 14 isomers are observed with toluene bonded at positions C 4 to C 17 inclusive; ii) a 2/1 oleate/toluene adduct where both fatty esters are bonded directly to the aromatic ring as for the 1/1 adduct; and iii) a 3/1 oleate/toluene adduct which is the product of the reaction of a methyl oleate dimer and a 1/1 oleate/toluene adduct to give a compound where only 2 of the 3 ester constituents are directly bonded.
The Friedel Crafts reactions of methyl linoleate and of olive, sesame, castor and soyabean oils were also briefly examined.
An attempt to prepare the triheptyl ether of 2 ethyl 2 hydroxymethyl 1,3 propanediol by reacting bromoheptane with the triol in the presence of bis(acetylacetonato)nickel as a catalyst was unsuccessful although the compound was prepared by the classical Williamson ether synthesis
Analysing migrant fertility using machine learning techniques : an application of random survival forest to longitudinal data from France
No full textFunding: This paper is part of the MigrantLife Project that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 834103).Background : The fertility of immigrants and their descendants is shaped by many factors. Survival and event history techniques are methods commonly used to study the determinants of individuals’ childbearing behaviour. Yet, machine learning techniques such as survival trees and tree ensembles are a useful alternative to classical methods. Objective : This paper analyses the predictors of having a first, second, and third birth among immigrants and their descendants in France. Methods : This study applies random survival forest (RSF) to longitudinal data from the Trajectories and Origins survey. Results : Our findings illustrate the potential of machine learning techniques in two ways. First, RSF allows us to identify the most important predictors of a life event. Our results show that predictors differ by parity: Educational level is the most important predictor of having a first child, whereas parents’ family size is the most important predictor of having a second and third child. Second, RSF allows us to easily detect and visualize interactions. For instance, our results of a four-way interaction show that highly educated migrants are closer to the native population in their childbearing behaviour than migrants with low education. Contribution : Our application of RSF to the analysis of immigrant fertility behaviour shows that the method can easily be applied in life course research and that research on migrant fertility should pay more attention to how education shapes childbearing patterns among minority populations.Peer reviewe
Increasing frequency and persistence of the summertime Greenland High regime not captured by a seasonal prediction model very large ensemble
No full textFunding: LMP is funded, in part, from award 2335762 from the US National Science Foundation to Columbia University.Weather regimes are widely used in weather prediction, but less often to study climate variability and change. Here, we use a year-round North American regime classification to identify summertime circulation trends from 1981 to 2024. We find large increases in the frequency, persistence and interannual variability of the Greenland High (GH) regime, similar to Greenland blocking. A simple Markov model shows that the observed increased GH frequency and variability can arise from increased persistence. We then show that a 10,000-member ensemble using SEAS5 seasonal model data fails to capture the observed trend in GH frequency because persistence trends are too weak. This occurs despite SEAS5 producing summers with more GH days and individual regimes more persistent than observed, so the issue is not simply an overall lack of persistence. Hence, the missing trends must arise from fundamental model deficiencies which develop on subseasonal timescales and are not rectified by initialization.Peer reviewe
The situated and everyday cultivation of transcultural capital in educational and home settings for migrant youth in Scotland
No full textScholars have identified that many young migrants employ transcultural capital to navigate difference in everyday life. In some cases, this enables migrants to resist social marginalisation, articulate empathy and challenge social hierarchies. This paper focuses on the significance and potential of the school, family and neighbourhood environments in the everyday cultivation of transcultural capital. To do this, we highlight the narratives of young migrants (age 16–18) in their final years of compulsory education, derived from a larger mixed-methods study on educational transitions in Scotland. This paper argues that (1) there is considerable variability between young migrants in the identification, development and mobilisation of transcultural capital and such capital is not to be assumed for migrant young people; (2) the ability to realise transcultural capital as an asset is highly situated in everyday contexts. This paper concludes that in order for transcultural capital to be mobilised, institutional contexts including schools need to have greater awareness of the processes through which transcultural capital can be nurtured for young migrants and a more intentional approach to fostering it.Peer reviewe
Transient protostellar cores in high mass star forming regions revealed by time-resolved synthetic imaging of dust emission
No full textFunding: RJS gratefully acknowledges an STFC Ernest Rutherford fellowship (grant ST/N00485X/1) and CJC gratefully acknowledges support from the STFC (grant ST/Y002229/1). MCL acknowledges support from a UK Science and Technologies Facilities Council (STFC) PhD studentship, under training grant ST/W507817/1 (project reference 2748654).The connection between dense gas cores and their infant protostars is key to understanding how stars form in molecular clouds. In this paper we investigate the properties, persistence, and protostellar content of cores that would be identified by a dendrogram analysis of 1.3 mm ALMA images. We use a time series of synthetic images produced by post-processing a simulation of star formation in a massive globally collapsing clump, with polaris to calculate dust radiative transfer and casa to generate synthetic ALMA data. Identifying sinks in the simulation with protostars, we find that most dendrogram-identified cores do not contain any protostars, with many cores being transient features associated with clumpy flow along feeder filaments. Cores with protostars generally host ≤3, and protostellar mass is not strongly correlated with the mass of the parent cores due to their transience and shifting boundaries. Calculating observationally relevant intensity-weighted average temperatures for all cores, we find that even at early times the core temperature distribution spans tens of Kelvin, and its width increases with time. The 1.3 mm peak and integrated intensity of the brightest mm core do not increase monotonically as the most massive associated protostar grows, indicating it cannot be assumed that brighter mm sources host more massive protostars. Leveraging the time domain, we test observational properties that have been proposed as potential evolutionary indicators and find that only the total 1.3 mm flux density of the region, the total 1.3 mm flux density in cores, and the number of cores show strong, statistically significant correlation with time.Peer reviewe
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