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The macro-social and environmental conditions in which people live, such as the level of a country’s development or inequality, are associated with brain-related disorders. However, the relationship between these systemic environmental factors and the brain remains unclear. We aimed to determine the association between the level of development and inequality of a country and the brain structure of healthy adults.
Methods
We conducted a cross-sectional study pooling brain imaging (T1-based) data from 145 magnetic resonance imaging (MRI) studies in 7,962 healthy adults (4,110 women) in 29 different countries. We used a meta-regression approach to relate the brain structure to the country’s level of development and inequality.
Results
Higher human development was consistently associated with larger hippocampi and more expanded global cortical surface area, particularly in frontal areas. Increased inequality was most consistently associated with smaller hippocampal volume and thinner cortical thickness across the brain.
Conclusions
Our results suggest that the macro-economic conditions of a country are reflected in its inhabitants’ brains and may explain the different incidence of brain disorders across the world. The observed variability of brain structure in health across countries should be considered when developing tools in the field of personalized or precision medicine that are intended to be used across the world.
This article takes a micro-history approach, focusing on the life of a man identified only in the British records as “Ned” in order to illuminate the complexity and slipperiness of categories of “race.” Ned had lived in the Zulu Kingdom and, after fleeing a civil war there, became employed in Natal by an English colonist-settler, Thomas Handley. Ned traveled with the Handley family to England in 1859, and during this time, unexpectedly “disappeared” from the Handley's residence near Sheffield. A manhunt ensued and, as locals ruminated on Ned's possible status as a “slave,” the case attracted the interest of the British and Foreign Anti-Slavery Society. Ned was eventually taken to London and housed in the Strangers’ Home for Asiatics, Africans and South Sea Islanders before his tragic death a few months later. His repeated escapes transfixed the public and resulted in detailed press coverage. Numerous parties became interested in his case, and complex and changing processes of racialization were key to the shifting ways in which he was represented. In this article, we both search for Ned's agency and volition, and demonstrate how the case also speaks to major issues in British history, including race, humanitarianism, and enslavement.
The period after 1850 is often assumed to have witnessed some amelioration in the operation of the game code. This article highlights the origins of a little-researched statute, the 1862 Poaching Prevention Act, which conversely augmented the existing game laws and, most significantly, bestowed new responsibilities and powers on the police to tackle poachers at a critical point in the development of the new county constabularies. This controversial measure owed much to the particular circumstances of the 1850s and early 1860s when the violence and criminality associated with the activities of poaching gangs in Midland and northern counties threatened both game preservation and the authority of the new police. In these circumstances, an alliance of magistrates, police leaders and parliamentary advocates successfully lobbied for new measures to deal with this specific class of offenders who were increasingly held as representative of a wider urban criminal class.
Plasmodium simium, a parasite of platyrrhine monkeys, is known to cause human malaria outbreaks in Southeast Brazil. It has been hypothesized that, upon the introduction of Plasmodium vivax into the Americas at the time of the European colonization, the human parasite adapted to neotropical anophelines of the Kerteszia subgenus and to local monkeys, along the Atlantic coast of Brazil, to give rise to a sister species, P. simium. Here, to obtain new insights into the origins and adaptation of P. simium to new hosts, we analysed whole-genome sequence (WGS) data from 31 P. simium isolates together with a global sequence dataset of 1086 P. vivax isolates. Population genomic analyses revealed that P. simium comprises a discrete parasite lineage with greatest genetic similarity to P. vivax populations from Latin America – especially those from the Amazon Basin of Brazil – and to ancient European P. vivax isolates, consistent with Brazil as the most likely birthplace of the species. We show that P. simium displays half the amount of nucleotide diversity of P. vivax from Latin America, as expected from its recent origin. We identified pairs of sympatric P. simium isolates from monkeys and from humans as closely related as meiotic half-siblings, revealing ongoing zoonotic transmission of P. simium. Most critically, we show that P. simium currently causes most, and possibly all, malarial infections usually attributed to P. vivax along the Serra do Mar Mountain Range of Southeast Brazil.
How do counterterrorism policies enable terrorist groups to thrive and survive? This article examines the relationship and how counterterrorism policies and political structures impact terrorist group success. While studies of terrorism have tended to separate the two phenomena, there is considerable complexity in the interactions between violent action and coercive state response. To demonstrate the complexity of these interactions, this article examines the persistence of three transnational terrorist groups from 1989 to 2022 – the Lashkar-e-Taiba, Jaish-e-Mohammad, and the Hizbul Mujahideen – that operate in the Kashmir region despite India’s coercive counterterrorism policies. While existing research emphasises macro-level factors in transnational terrorism, this article, based on original qualitative data, demonstrates the critical importance of granular, localised opportunities for terrorist groups to carry on. We show how these structures interact with civilian perceptions of state legitimacy and security to create nuanced patterns of support. In doing so, we challenge simplistic explanations of terrorist recruitment and resilience. The article dispels existing misconceptions about the efficacy of coercive counterterrorism to end militant groups and further suggests that softer, non-coercive approaches might not necessarily generate public sympathy. In fact, select counterterrorism policies might inadvertently legitimise violence by extremist groups to their constituency and increase sympathy in the process.
Heath forests, or known locally as kerangas, in Indonesia and Malaysia form a distinct and understudied ecoregion. We document the distribution and ecological significance of the largest extent of kerangas in Kalimantan, Indonesian Borneo. We mapped 16,586 km2 of kerangas to the nearest one square kilometre across Kalimantan, showing a significant reduction from previous estimates. About 19% of this area exists as a poorly documented mosaic landscape in Central Kalimantan’s Rungan-Kahayan region. Here, peat-based forests transition to heath and dipterocarp forests, making it difficult to reliably classify these forests for conservation planning. Using remote sensing and tree plot data, we identified three forest types—kerangas, low pole, and mixed swamp. Vegetation structure is influenced by soil, topography, and hydrology, while peat depth and elevation affect species diversity. Our findings indicate that these forests are dynamic ecosystems with diverse vegetation communities adapted to peat as well as sandy soils. Lowland heath forests in Rungan-Kahayan exhibits higher tree densities compared to other Bornean heath forests, reflecting unique ecological adaptations to challenging environments. Despite covering just 3% of Kalimantan’s forest area, these ecosystems remain largely unprotected, facing threats from land conversion and fire. Our study highlights the ecological complexity of kerangas and underscores the urgent need for targeted conservation and further research on these forests.
English learners (ELs) with disabilities are disproportionately less likely than their EL peers without disabilities to be reclassified as Fluent English Proficient (FEP) in US public schools. Research has begun to explore how state reclassification policies, specifically the criteria needed to be considered FEP, may contribute to reclassification disparities. Given the complexities of measuring and understanding English language proficiency (ELP) growth for ELs with disabilities, there have been calls for states to incorporate teacher or team input as a criterion for reclassification. Research, however, has yet to examine how teachers make sense of ELP data for ELs with disabilities and ultimately make reclassification recommendations. This qualitative case study fills this gap, investigating the data interpretation and decision-making of teachers in one urban school district. It documents how teachers’ beliefs about standardized ELP assessment data coupled with a scarcity of resources and training contributed to reclassification decision-making driven not by data but by teachers’ values and instincts.
Childless individuals have historically faced stigma with assumptions that they lack an interest in future generations because they do not directly contribute to genetic lineage. Individuals share approximately half of their genes with siblings, 12.5% with first cousins, and 6.25% with first cousins’ children. Norwegian census data (2005−2023), reflecting similar trends to the US, UK, and other European countries, indicates a moderate difference in the number of siblings (Parents: 2.03 [women and men]; Childless: 1.88 [women], 1.94 [men]) and nieces/nephews (Parents: 3.99 [women], 4.03 [men]; Childless: 3.32 [women], 3.42 [men]) for 514,777 women and 532,834 men, respectively. By linking four generations through grandmothers, both childless and childbearing women had a slightly higher number of biological extended family members (Parents: 9.63 cousins with 15.79 children; Childless: 8.66 cousins with 12.22 children). Linking four generations for men, numbers were similar: Parents: 9.68 cousins with 15.91 children, Childless: 8.83 cousins with 12.44 children. Based on the average number of children who are parents, the childless have an average genetic fitness that is 49% of that for parents for the next generation. Both parents and childless individuals have a stake in future generations through their biological extended family.
To what extent can drones be the primary determinants of victory in warfare? This question is at the heart of the drone revolution debate in security studies. Proponents of a drone revolution argue that drones provide ‘game-changing characteristics’, act as ‘magic bullets’ against adversaries, and even provide the key defence to decide the ‘fate of nations’. Sceptics disagree, arguing that no matter the nuances or contexts of war, drones can never be considered the primary determinant of victory. In this article, we argue that the two sides of the debate rest upon a false dichotomy – that technologies must either be revolutionary or evolutionary. We reappraise country-specific case studies used by both sides of the debate: the Ethiopia–Tigray War, the Houthi–Saudi War, and the Russia–Ukraine War. Our analysis reveals a welcome synthesis; the impact of drone employment depends on the types of war waged, the drone capabilities deployed, and the political objectives sought in each conflict. In this sense, drones can have an impact on war that is sometimes ordinary and sometimes revolutionary. It is only by clarifying the analytical scope of the debate that the impact of drones on the practice of war can be fully understood.
The relative education model holds that educational attainment reflects existing socioeconomic advantages that are associated with participation rather than spurring political participation on its own. Yet, emerging research on compensation effects suggests that greater educational attainment leads to increased political engagement among more marginal populations in which political socialization is less likely to occur outside of schools. We argue that the relative education model will better describe the relationship between education and voting patterns among more advantaged groups. We test our expectations by estimating the relative education model within racial and ethnic groups in the U.S. using data from the Current Population Survey’s (CPS) Voting and Registration Supplement from 1978 to 2020. We find that for relatively highly educated White and Asian American voters, each additional year of education yields diminishing returns to turnout. For Black and Latino voters, additional years of education are positively associated with turnout regardless of relative education. The results suggest that opportunities remain to reduce racial turnout gaps and boost political participation by addressing racial gaps in educational attainment.
Measurements of the ionisation state of the intergalactic medium (IGM) can probe the sources of the extragalactic ionising background. We provide new measurements of the ionising emissivity of galaxies using measurements of the ionising background and ionising photon mean free path from high-redshift quasar spectra at $2.5 \lt z \lt 6$. Unlike most prior works, we account for radiative-transfer effects and possible neutral islands from the tail of reionisation at $z \gt 5$. We combine our results with measurements of the UV luminosity function to constrain the average escaping ionising efficiency of galaxies, $\langle f_{\textrm{esc}} \xi_{\textrm{ion}}\rangle_{L_{\textrm{UV}}}$. Assuming galaxies with $M_{\textrm{UV}} \lt -11$ emit ionising photons, we find $\log (\langle f_{\textrm{esc}} \xi_{\textrm{ion}}\rangle_{L_{\textrm{UV}}}/{\textrm {erg}^{-1}Hz}) = 24.47_{-0.17}^{+0.09}$ and $24.75_{-0.28}^{+0.15}$ at $z=5$ and 6, and $1\sigma$ upper limits of $24.48$ and $24.31$ at $z = 2.5$ and 4, respectively. We also estimate the population-averaged $f_{\textrm{esc}}$ using measurements of intrinsic ionising efficiency from JWST. We find $\langle f_{\textrm{esc}} \rangle = 0.126_{-0.041}^{+0.034}$ and $0.224_{-0.108}^{+0.098}$ at $z=5$ and 6, and $1\sigma$ upper limits of $f_{\textrm{esc}}\lt 0.138$ and $0.096$ at $z=2.5$ and 4, respectively, for $M_{\textrm{UV}} \lt -11$. Our findings are consistent with prior measurements of $f_{\textrm{esc}} \lesssim 10\%$ at $z \leq 4$, but indicate a factor of several increase between $z = 4$ and 6. The steepness of this evolution is sensitive to the highly uncertain mean free path and ionising background intensity at $z\gt5$. Lastly, we find $1.10^{+0.21}_{-0.39}$ photons per H atom are emitted into the IGM between $z=6$ and $=5.3$. This is $\approx 4\times$ more than needed to complete the last 20% of reionisation absent recombinations, suggesting that reionisation’s end was likely absorption-dominated.
The unchecked rise in global plastic production has resulted in widespread pollution and exposure to hazardous chemicals. Over 16,000 chemicals are used across the plastics life cycle, with thousands meeting criteria for persistence, bioaccumulation, mobility and toxicity. Many remain unregulated under existing multilateral environmental agreements. In response, the United Nations Environment Assembly has mandated the development of an international, legally binding instrument to end plastic pollution. Current treaty negotiations have begun addressing a short list of chemicals, yet significant gaps remain. These include insufficient regulatory mechanisms, lack of chemical transparency and reliance on ineffective recycling strategies that reintroduce toxic substances into consumer products. The presence of harmful chemicals in plastics contributes to major public health burdens and is an environmental threat, with high annual costs that reduce the potential for economic development through safer recycling. Vulnerable populations, including children, reproductive-aged individuals, and frontline communities, face heightened risks. To address this, we recommend the following three critical actions for the treaty: (1) globally regulating chemicals of concern based on hazard; (2) mandating transparency of plastic chemical composition and (3) designing plastics using safe-by-design principles and essential-use criteria. Group-based regulation, which would consider categories of related chemicals, should replace individual chemical approaches to prevent regrettable substitutions. Binding, global obligations, rather than fragmented or voluntary measures, are vital for sustainability, chemical safety, circularity and accountability across the plastics life cycle. A strong treaty is a critical opportunity to achieve a safer, more sustainable future for human and environmental health.
The Chinese Cultural Revolution reverberated the world over. As many scholars have shown, Maoism, an amorphous body of ideas originating from Chairman Mao Zedong, fed into different facets of the U.S. New Left, becoming one of the most powerful political forces in the 1960s. This article examines the fragmentation of U.S. Maoism in the 1970s to further illuminate the relationship between Mao’s China and its devout followers in the heartland of capitalism. As Sino-American “rapprochement” unfolded, U.S. Maoists travelled to China in droves to learn the essence of Mao’s revolution and replicate their own back home. They sought to build a united front party modeled after the Chinese Communist Party, while debating the “correct” line that their party should follow, an ideological altercation that fueled factional tension. Drawing on an array of U.S. and Chinese sources, this article argues that the quest for unity and struggle, the core tenet of Maoism, precipitated its downfall in the United States.
The connection between the drag and vorticity dynamics for viscous flow over a bluff body is explored using the Josephson–Anderson (J–A) relation for classical fluids. The instantaneous rate of work on the fluid, associated with the drag force, is related to the vorticity flux across the streamlines of a background potential flow. The vorticity transport itself is examined by aid of the Huggins vorticity-flux tensor. The analysis is performed for three flows: flow over a sphere at Reynolds numbers $Re=200,3700$, and flow over a prolate spheroid at $Re=3000$ and $20^{\circ }$ incidence. In these flows, the vorticity transport shifts the flow away from and towards the ideal potential flow, with a net balance towards the former effect thus making an appreciable contribution to the drag. The J–A relation is first demonstrated for the flow over a sphere at $Re=200$. The drag power injection is related to the viscous flux of azimuthal vorticity from the wall into the fluid, and the advection of vorticity by the detached shear layer. In the wake, the azimuthal vorticity is advected towards the wake centreline and is annihilated by viscous effects, which contributes a reduction in drag. The analysis of the flow over a sphere at $Re=3700$ is reported for the impulsively started and stationary stages, with emphasis on the effects of unsteady two-dimensional separation and turbulent transport in the transitional wake. The turbulent flux in the wake enhances the transport of mean azimuthal vorticity towards the wake centreline, and is the main driver of the recovery of enthalpy between the rear point of the sphere and far downstream. The rate of work on the fluid by the drag force for a prolate spheroid is mostly due to the transport of vorticity along the separated boundary layers. Primary and secondary separation contribute oppositely to the power injection by the drag force, while the large-scale vortices only re-distribute vorticity without a net contribution. A mechanism for secondary separation is proposed based on the theory of vortex-induced separation.
In recent years, Southern Thailand has witnessed an increase in surface planted with oil palm, driven primarily by smallholders who contribute over 90% of Thailand’s oil palm output. Despite their significant contribution, oil palm smallholders have consistently achieved lower yields compared to agro-industries, and limited research has been conducted to understand the limiting factors, such as management practices. Structured interviews were conducted to gather information about management practices and estimate the fresh fruit bunch yield in a network of 18 plantations in Krabi province, Thailand. A clustering approach, combining principal component analysis and hierarchical cluster analysis, was used to characterise the diversity of smallholder management practices. Four clusters of management practices were highlighted, characterised by varying intensities of fertiliser application (nitrogen, phosphorus, and potassium), mechanical versus chemical weeding, and harvest intervals. Notably, the farmers in our study applied less fertiliser, on average, than the recommendations of Thai Good Agricultural Practices. A significant portion of plots in the area (12 out of 18 plots) achieved good yields compared to attainable yields. A clear relationship between management practices and yield could however not be established. The large diversity of oil palm smallholders’ management practices and their performances highlighted in this study need to be better taken into account and understood in order to improve sustainability and foster certification schemes such as Roundtable on Sustainable Palm Oil (RSPO).
Alcohol misuse among women has risen compared to men. Women experience barriers to engaging in patient-centered comparative effectiveness research (CER) that, in turn, limits the evidence base for addressing alcohol misuse in this population. In this manuscript, we describe WomenWise, a community-partnered project and outline how we co-developed community focused CER training curriculum and collaboratively planned future partnered learning sessions (PLSs) with Community Advisory Board (CAB) feedback. Through this approach we aim to empower women to contribute to future patient-centered CER and enhance the stakeholder capacity for future patient-centered research.
Population is a key factor of national power. Declining fertility rates, especially in major economies, are reshaping global power dynamics by shrinking workforces amidst aging populations. In response, more nations are adopting techno-natalist policies, promoting reproductive technologies (“reprotech”) like IVF to increase birth rates. Advances in genetic embryo selection, gene editing, in vitro gametogenesis, and artificial wombs could further enhance these policies by improving birth rates, health, and human capital. This article examines current and emerging reprotechnologies, the policy landscape, socioeconomic and geopolitical implications, and future research directions. By shaping national and global gene pools, reprotech policies and practices offer a paradigmatic case of gene–culture coevolution. If these technologies prove safe and effective, nations that embrace them are likely to gain geopolitical and evolutionary advantages over those that do not.
Many people experiencing mental ill health are trapped in cycles of worsening social exclusion. Individual Placement and Support (IPS) is being implemented to support those with mental ill health into employment. However, this intervention does not address the many challenges faced by those who are more vulnerable and is less effective for those with more severe clinical presentations. Although National Health Service (NHS) guidance suggests broader support is needed, there is little clarity over what this should look like. We discuss one model, drawing on years of experience facilitating user-led services at Lambeth Vocational Services, implementing a genuinely person-centred, trust-based approach to facilitate social inclusion.
Amateur and professional athletes often consume protein supplements to accelerate muscle gain; however, it has been suggested that these products not only are associated with risks when consumed excessively. Several recent reports have indicated that certain products are contaminated with heavy metals. Therefore, in this study, we aimed to investigate protein powders in Hungary for heavy metal contamination. A total of 22 commercially available protein powders (including whey, vegan, and beef based) were purchased on the internet for testing. We analysed the samples using laser-induced breakdown spectroscopy (LIBS) and inductively coupled plasma mass spectrometry (ICP-MS) to assess heavy metal contamination. The products were analysed for the presence of 16 elements (Be, Al, Cr, Mn, Co, Ni, Cu, As, Se, Rb, Cd, Sb, Cs, Ba, Hg, and Pb). The LIBS spectral analysis revealed the characteristics of the protein elements (C, C2, H, N, and O) and alkaline metals (Ca, Na, K, and Mg), which were consistent with the previous results. Neither LIBS nor ICP-MS measurements detected significant heavy metal content in the investigated samples above the limit specified in the regulations. Heavy metal contamination of protein supplements can be a serious health threat. Based on the varied results of the previous studies, it is prudent to include testing for heavy metals as part of the routine and mandatory quality control of these products.