To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Annona crassiflora is a fruit-bearing tree species native to the Cerrado that has ecological and economic potential, mainly due to the production of attractive and useful fruits for a number of species, including humans. To provide a basis for its conservation and breeding, the objective was to assess the diversity and genetic structure of natural populations of the species using inter-simple sequence repeat (ISSR) molecular markers. Eight populations were analysed in the state of Minas Gerais, Brazil, with 24 individuals randomly sampled in each population, reaching a total of 192 trees. Ten ISSR primers were used, resulting in high genetic diversity for the combined data (H* = 0.35 and I* = 0.52). However, a wide range of representative values was observed in the individual assessment of populations, with JAN, GM and MC standing out for their low genetic diversity, resulting in H* of 0.19, 0.23 and 0.24 and I* of 0.28, 0.34 and 0.35, respectively. An analysis of molecular variance showed greater variation within populations, indicating gene flow (Nm), but genetic differentiation between populations was moderate. Bayesian analysis, although resulting in four genetic groups, revealed the presence of a majority group for the GM and JAN populations. We propose measures to maintain these populations, such as raising awareness of local extractivism and planting genetically divergent seedlings. Furthermore, we recommend including of all populations in conservation and breeding programmes, aiming to cover the maximum genetic variation for the species.
A simplified configuration was developed to facilitate the mode transition process within an over-under Turbine-Based Combined Cycle (TBCC) inlet. Leveraging dynamic mesh technology, an unsteady numerical simulation of the mode transition was conducted, emphasising the flow characteristics of the mode transition and the impact of key similarity criteria numbers. The findings indicate that at an incoming Mach number of 2.0, the mode transition is paired with a continuous alteration in the capture mass flow of the high-speed duct. This continual change instigates the inlet unstarting, with subsequent flow characteristics being contingent on the historical effect, exhibiting a degree of hysteresis characteristics. When the scale effect is considered, it is observed that a larger model scale results in higher Reynolds (Re) and Strouhal (St) numbers. This directly contributes to a notable delay in the unstart moment, a decrease in the unstart interval, and an enlargement of the hysteresis loop. An examination of control variables reveals that the Re number marginally influences mode transition characteristics, while the St number’s effect constitutes approximately 90% of the scale effect. This conclusively demonstrates that the St number is the predominant similarity criterion number in the mode transition process.
Scale dependence of local shearing motion is investigated experimentally in decaying homogeneous isotropic turbulence generated through multiple-jet interaction. The turbulent Reynolds number, based on the Taylor microscale, is between approximately 900 and 400. Velocity fields, measured using particle image velocimetry, are analysed through the triple decomposition of a low-pass filtered velocity gradient tensor, which quantifies the intensities of shear and rigid-body rotation at a given scale. These motions manifest predominantly as layer and tubular vortical structures, respectively. The scale dependence of the moments of velocity increments, associated with shear and rigid-body rotation, exhibits power-law behaviours. The scaling exponents for shear are in quantitative alignment with the anomalous scaling of the velocity structure functions, suggesting that velocity increments are influenced predominantly by shearing motion. In contrast, the exponents for rigid-body rotation are markedly smaller than those predicted by Kolmogorov scaling, reflecting the high intermittency of rigid-body rotation. The mean flow structure associated with shear at intermediate scales is investigated with conditional averages around locally intense shear regions in the filtered velocity field. The averaged flow field exhibits a shear layer structure with aspect ratio approximately 4.5, surrounded by rotating motion. The analysis at different scales reveals the existence of self-similar structures of shearing motion across various scales. The mean velocity jump across the shear layer increases with the layer thickness. This relationship is well predicted by Kolmogorov's second similarity hypothesis, which is useful in predicting the mean characteristics of shear layers across a wide range of scales.
Myocardial infarction is rare in children but frequently occurs unexpectedly with atypical presentation. It can cause a progressive lethal course unless prompt treatment is initiated.
Methods:
Paediatric cases of myocardial infarction diagnosed by the presence of ischaemic myocardial insults and symptomatic ventricular dysfunction were reviewed retrospectively.
Results:
Eighteen patients (5 days to 14 years of age; median 3 months) with myocardial infarction were studied. The aetiology was variable, including congenital coronary anomalies: anomalous left coronary artery from pulmonary artery (five patients), pulmonary atresia with intact ventricular septum with right ventricle-dependent coronary circulation (four), anomalous aortic origin of left coronary artery (three), and Williams syndrome with supravalvar aortic stenosis (one). Two acquired coronary anomalies occurred in one patient with undiagnosed Kawasaki disease with complete thrombotic obstruction of the left coronary artery and another with post-transplant cardiac allograft microangiopathy. Three patients developed thromboembolic coronary artery incidents in normal coronary anatomy. Fourteen patients were less than 1 year of age (78%). Electrocardiographic abnormalities were noted in all patients. Four patients required extracorporeal membrane oxygenation support for severe ventricular dysfunction, none of whom survived. Five patients underwent heart transplant. Five patients died during the same hospitalisation, and one patient died after discharge (overall mortality 33%). Transplant-free survival was 39%.
Conclusion:
Most myocardial infarction occurred in infants who presented with abrupt onset of non-specific clinical manifestations with progressively deteriorating haemodynamic status resulting in poor transplant-free survival rate. Early diagnosis and treatment are essential to prevent catastrophic outcomes.
Large and persistent racial disparities in land-based wealth were an important legacy of the Reconstruction era. To assess how these disparities were transmitted intergenerationally, we build a dataset to observe Black households’ landholdings in 1880 alongside a sample of White households. We then link sons from all households to the 1900 census records to observe their economic and human capital outcomes. We show that Black landowners, relative to laborers, transmitted substantial intergenerational advantages to their sons, particularly in literacy and homeownership. However, such advantages were small relative to the racial gaps in measures of economic status.
Let $\alpha $ be a complex valued $2$-cocycle of finite order of a finite group $G.$ The nth Frobenius–Schur indicator of an irreducible $\alpha $-character of G is defined and its properties are investigated. The indicator is interpreted in general for $n =2$ and it is shown that it can be used to determine whether an irreducible $\alpha $-character is real-valued under the assumption that the order of $\alpha $ and its cohomology class are both $2$. A formula, involving the real $\alpha $-regular conjugacy classes of $G,$ is found to count the number of real-valued irreducible $\alpha $-characters of G under the additional assumption that these characters are class functions.
In 1978, William Alwyn Lishman's Organic Psychiatry: The Psychological Consequences of Cerebral Disorder was published, fostering the development of neuropsychiatry and leading to the recognition of Lishman as the father of neuropsychiatry. This article is a narrative account of his personal struggles, as well as conceptual dilemmas he dealt with while writing this book, and how through its four editions it has evolved to become an anchor for psychiatrists as they seek to develop understanding of the workings of the brain, and a beacon for them when they discuss clinical implications of diagnosis with patients and families.
The COVID-19 pandemic destabilised the political, social, and economic life of countries as it spread around the world. It posed multiple threats to individuals, societies, and across different domains of life, highlighting their intersectionality and uneven impacts. The paper focuses on the UK and South Korea, countries which took very different paths in framing and addressing the crisis. It draws on secondary data and an integrated critical human security and state capacity approach to compare how state responses, institutional capacity, and the mobilisation of policy instruments themselves construct constellations of insecurity which intersect with human security and vulnerability. It will demonstrate the structural constraints that have continued to shape vulnerability and the dynamics of human security and insecurity in turbulent times.
Understanding the relationships between cetaceans and their environment is crucial for conservation. This study examined humpback whales in Bahía de Banderas, Mexico, identifying key calving habitats. From 2018 to 2023, 1066 sightings were recorded, including 242 mother–calf groups, 109 mating groups, and 715 other groups. Spatial analysis revealed a non-random distribution; both the Kruskal–Wallis and Wilcoxon–Mann–Whitney tests detected significant differences (P < 0.05) in site preferences. Calving mothers favoured habitats with a mean depth of 59 m and a distance of 2 km from the coast, while mating groups preferred locations at 126 m and 4 km, and other groups chose areas at 149 m and 4 km. All groups were found in relatively flat areas around 2° seafloor slope. A dispersion test indicated a significant relationship between the location of calving mothers and environmental factors. K-means clustering showed 83.6% of calving mothers' sightings at depths less than 40 m and 2 km from the coast. Ensemble species distribution models identified three critical calving areas: one large area (261.8 km2) along the north coast and two smaller areas (9.5 and 5.4 km2) at the southern end of the bay. This study highlights Bahía de Banderas as a vital breeding habitat for humpback whales, providing insights for conservation strategies to protect calving grounds during the breeding season.
The present study investigates streamwise ($\overline {u^2}$) energy-transfer mechanisms in the inner and outer regions of turbulent boundary layers (TBLs). Particular focus is placed on the $\overline {u^2}$ production, its inter-component and wall-normal transport as well as dissipation, all of which become statistically significant in the outer region with increasing friction Reynolds number ($Re_{\tau }$). These properties are analysed using published data sets of zero, weak and moderately strong adverse-pressure-gradient (APG) TBLs across a decade of $Re_{\tau }$, revealing similarity in energy-transfer pathways for all these TBLs. It is found that both the inner and outer peaks of $\overline {u^2}$ are always associated with local maxima in the $\overline {u^2}$ production and its inter-component transport, and the regions below/above each of these peaks are always dominated by wall-ward/away-from-wall transport of $\overline {u^2}$, thereby classifying the $\overline {u^2}$ profiles into four distinct regimes. This classification reveals existence of phenomenologically similar energy-transfer mechanisms in the ‘inner’ and ‘outer’ regions of moderately strong APG TBLs, which meet at an intermediate location coinciding with the minimum in $\overline {u^2}$ profiles. Conditional averaging suggests existence of similar phenomena even in low $Re_{\tau }$ canonical and/or weak APG TBLs, albeit with the outer-region mechanisms weaker than those in the inner region. This explains the absence of their $\overline {u^2}$ outer peak and the dominance of $\overline {u^2}$ wall-normal transport away from the wall, which potentially originates from the inner region. Given that the wall-ward/away-from-wall transport of $\overline {u^2}$ is governed by the $Q_4$(sweeps)/$Q_2$(ejections) quadrants of the Reynolds shear stress, it is argued that the emergence of the $\overline {u^2}$ outer peak corresponds with the statistical dominance of $Q_4$ events in the outer region. Besides unravelling the dynamical significance of $Q_2$ and $Q_4$ events in the outer region of TBLs, the present analysis also proposes new phenomenological arguments for testing on canonical wall-turbulence data at very high $Re_{\tau }$.
During the military regime in Brazil (1964–1985), enrollment ratios in primary education grew substantially in the first decade under dictatorship, but stagnated in the mid-1970s. This paper shows that education spending might depend on the levels of centralisation in tax matters. Using panel data regressions and qualitative evidence, we argue that a massive big push industrialisation programme increased the pressure on external accounts, leading the government to intensify an export incentive policy based on tax subsidies that decreased the income of subnational governments. As a result, the capacity of funding mass education was compromised in the second half of the 1970s.
We conducted an axisymmetric numerical study of drop impact on a thin film of the same liquid in order to generate maps identifying the fluid elements in the drop and film that are transferred to the corolla during impact. We find that mass contribution from the drop comes from a surprisingly thin surface layer on the drop, and furthermore, that the shape of this layer in the drop and the film scales with film thickness, not the Weber number and Reynolds number as one might expect. The maps could be used to tailor drop composition for applications such as coatings or encapsulations.
Rotating Rayleigh–Bénard convection denotes the convection between a warm plate and a cold plate in a rotating environment. It is a classic model for understanding convective vortices in the atmosphere and ocean. The influence of background rotation on fluid inertia breaks the symmetry between cyclones and anticyclones. Such a symmetry breaking could be represented by vorticity skewness, which still lacks a systematic theory. Rapidly rotating convection with stress-free boundaries and unit Prandtl number is a convenient starting point. The investigation starts from the convective onset stage, where the vortices grow stationarily. Asymptotic analysis shows that the volumetric vorticity skewness $S$ is produced by the interaction between the $n=0,1$ and $n=1,2$ vertical eigenmodes. The $n=0$ (barotropic) mode contributes positively to $S$ mainly by stretching the vertical relative vorticity, an ageostrophic effect. The $n=2$ mode makes a minor negative contribution to $S$ by preferentially intensifying the outflow over the inflow, a non-hydrostatic effect. The theory predicts $S$ to be proportional to the global Rossby number defined with the volumetric standard deviation of vorticity, ${Ro_g}$. The proportional factor does not depend on the Rayleigh and Ekman numbers, agreeing with direct numerical simulations. Then the system enters the equilibrium stage. The stretching of vertical vorticity still contributes to $S$ dominantly. At ${Ro_g}\gtrsim 0.5$, the emergent unsteady flow significantly suppresses the asymmetry between the inflow and outflow strength, and weakens its influence on $S$.