We report laboratory results on bubble plumes released from a point source into a homogeneous liquid environment of depth $H$ and rotation rate $\varOmega$. The gas phase is characterised by the non-dimensional slip velocity $u_N=u_s/(BH^{-1})^{1/3}$, where $u_s$ is the slip velocity of the dominant bubble species and $B$ is the source buoyancy flux. The effects of the background rotation are characterised by the Rossby number $Ro=(B\varOmega ^{-3})^{1/4}/H$. We study the regimes $0.06\lessapprox u_N\lessapprox 0.36$ and $0.03\lessapprox Ro\lessapprox 0.3$. We establish that, from $\varOmega t\approx 2.3$, the growth of the maximum plume width $b_{max}$ is slowed down compared to the non-rotating $t^{3/4}$ power law, where $t$ is the time. At $\varOmega t\approx {\rm \pi}$, the plume axis starts to tilt laterally and causes a slowdown of the rise of the height $h_c$ of the plume silhouette centroid from the $t^{3/4}$ power law. These critical times do not depend on $u_N$. After $\varOmega t \approx {\rm \pi}$, the slip velocity counteracts the effects of rotation such that $h_c$ rises faster for larger $u_N$. The subsequent onset of the anticyclonic plume precession causes the disintegration of the rising plume front into vertical columnar structures for $Ro\lessapprox 0.15$. Once the plume reaches the free surface, the subsurface lateral dispersion of bubbles is increased compared to the non-rotating case. However, background rotation suppresses the lateral dispersion of bubbles at the free surface. We find that, asymptotically, the surface area $A$ affected by the bubbles scales as $(B\varOmega ^{-1})^{1/2}t$, and the proportionality factor reduces with an increasing $u_N$.

Circular milling, a stunning manifestation of collective motion, is found across the natural world, from fish shoals to army ants. It has been observed recently that the plant-animal worm Symsagittifera roscoffensis exhibits circular milling behaviour, both in shallow pools at the beach and in Petri dishes in the laboratory. Here we investigate this phenomenon experimentally and theoretically, from a fluid dynamical viewpoint, focusing on the effect that an established circular mill has on the surrounding fluid. Unlike systems such as confined bacterial suspensions and collections of molecular motors and filaments that exhibit spontaneous circulatory behaviour, and which are modelled as force dipoles, the front–back symmetry of individual worms precludes a stresslet contribution. Instead, singularities such as source dipoles and Stokes quadrupoles are expected to dominate. We analyse a series of models to understand the contributions of these singularities to the azimuthal flow fields generated by a mill, in light of the particular boundary conditions that hold for flow in a Petri dish. A model that treats a circular mill as a rigid rotating disc that generates a Stokes flow is shown to capture basic experimental results well, and gives insights into the emergence and stability of multiple mill systems.

This paper quantifies the welfare gains from Social Security when individuals face uninsurable longevity risk. While past researchers have studied this basic question, we do so from a unique perspective. In contrast to traditional macroeconomic models that abstract from specific linkages between parents and children, in our model, children are born to specific parents whose longevity is uncertain. And because parental asset holdings evolve over the life of the parent, children face uninsurable bequest income risk in addition to their own longevity risk. We find that Social Security improves ex ante expected utility by 3.4% of lifetime consumption (for the second generation). Because our baseline analysis assumes full information and optimal hedging of longevity risk, we treat these welfare gains as a conservative estimate, and we show that the gains are significantly larger when individuals fail to hedge their longevity risk.

This article examines why Japan is a prominent exception to the global trend towards recognition of same-sex marriage and evaluates the prospects for change. It does so through an analysis of five cases brought on Valentine's Day – 14 February 2019. Unlike many jurisdictions where religious opposition to same-sex relationships has been intense and sometimes violent, Japan has a history of relative tolerance towards LGBT individuals. Nonetheless, despite the creation of civil partnership ordinances in some localities, national legislation seems unlikely, and a group of lawyers filed suit in five district courts across Japan. The litigation was brought under the State Redress Act and is based on tort rather than directly on constitutional doctrine. It claims that marriage equality is constitutionally required and that the failure of the government to recognize same-sex marriage constitutes a tort that has harmed the LGB plaintiffs and entitles them to compensation. This article analyzes the nature of the cause of action founded on the State Redress Act, and examines the arguments, which are based more on the plaintiffs’ suffering than on their desire for self-expression. Subsequently, it presents and evaluates the possible outcomes

Joseph Brennan, as secretary of the Irish Department of Finance (1923–7) and chair of the Irish Currency Commission (1927–43), was a pivotal influence on Irish banking and currency affairs. Yet, within the existing literature, his adherence to conservative British norms is seen as providing a ‘bleak prescription’ for the Irish economy. However, such a view ignores the fact that Brennan was far from dogmatic on banking and currency issues and underplays his incrementalist, and often internationalist, approach to the development of Irish monetary institutions. Brennan's actions up to the early 1940s were based on the realities of Ireland's slowly receding economic and intellectual dependency on Britain, a ‘dependency’ often misrepresented in the existing literature as a more primitive, pre-Keynesian, conservative approach. However, rather than acting as a restraining influence on Irish economic development, the policies Brennan advocated enabled Ireland to avoid the instability associated with many smaller, emerging nation states in the 1920s and 1930s. The focus on continuity – which guaranteed currency and banking stability – represented the realities of Ireland's reliance on the sluggish British economy in the decades after independence. Brennan's achievement, in helping to sustain banking and currency stability notwithstanding economic uncertainty, a fragile political environment (and suspicious banking interests), deserves wider acknowledgement.

Palaeolandscape reconstructions at the German North Sea coast are essential for the understanding of coastal changes and dynamic landscape-forming processes. This study contributes to reconstructing Holocene coastal changes in the back-barrier area of the East Frisian island of Norderney and draws conclusions on the local palaeogeography. Five sediment cores were analysed in terms of sedimentology (grain-size distribution), geochemistry (TOC, TIC, N, C/N), microfauna (foraminifers and ostracods) and 13 radiocarbon dates. In order to identify driving environmental factors and support the facies interpretation, multivariate statistics (PCA) were carried out. Additional cores from the surrounding area (WASA Project and ‘Landesamt für Bergbau, Energie und Geologie’ (LBEG) Hannover) enabled correlation of the investigated cores over a transect of ~6 km, showing six depositional environments, which can be used for landscape reconstruction. Deposition starts with periglacial (aeolian and glaciofluvial) Pleistocene sediments, with subsequent pedogenesis followed by swamp conditions that develop into a salt marsh. The overlying tidal-flat sediments are partially cut by (fossil and recent) channel deposits. A hiatus at the base of the tidal-flat deposits that spans some 3000 years hints at their reworking caused by a combination of antrophogenic coastal protection measures and the impact of storms. Furthermore, based on the profile correlation and the age data, a widespread salt-marsh area with a minimum age of ~4000 cal BP is defined for the ‘Hohes Riff’ in the southwestern back-barrier of Norderney Island.

This study presents an ultra-wideband receiver front-end, designed for a reconfigurable frequency modulated continuous wave radar in a 130 nm SiGe BiCMOS technology. A variety of innovative circuit components and design techniques were employed to achieve the ultra-wide bandwidth, low noise figure (NF), good linearity, and circuit ruggedness to high input power levels. The designed front-end is capable of achieving 1.5–40 GHz bandwidth, 30 dB conversion gain, a double sideband NF of 6–10.7 dB, input return loss better than 7.5 dB and an input referred 1 dB compression point of −23 dBm. The front-end withstands continuous wave power levels of at least 25 and 20 dBm at low band and high band inputs respectively. At 3 V supply voltage, the DC power consumption amounts to 302 mW when the low band is active and 352 mW for the high band case, whereas the total IC size is $3.08\, {\rm nm{^2}}$.

Posttraumatic stress disorder (PTSD) is a complex mental disorder afflicting approximately 7% of the population. The diverse number of traumatic events and the wide array of symptom combinations leading to PTSD diagnosis contribute substantial heterogeneity to studies of the disorder. Genomic and complimentary-omic investigations have rapidly increased our understanding of the heritable risk for PTSD. In this review, we emphasize the contributions of genome-wide association, epigenome-wide association, transcriptomic, and neuroimaging studies to our understanding of PTSD etiology. We also discuss the shared risk between PTSD and other complex traits derived from studies of causal inference, co-expression, and brain morphological similarities. The investigations completed so far converge on stark contrasts in PTSD risk between sexes, partially attributed to sex-specific prevalence of traumatic experiences with high conditional risk of PTSD. To further understand PTSD biology, future studies should focus on detecting risk for PTSD while accounting for substantial cohort-level heterogeneity (e.g. civilian v. combat-exposed PTSD cases or PTSD risk among cases exposed to specific traumas), expanding ancestral diversity among study cohorts, and remaining cognizant of how these data influence social stigma associated with certain traumatic events among underrepresented minorities and/or high-risk populations.

Finding the ways that work to deliver the innovation needed should be given parity of esteem with getting the prices right as a focus of the economics profession and policy systems. Learn from experience as regards carbon pricing and carbon-reducing innovation; insights from the latter coming mainly from the US, China and Europe; demographically relatively small countries – Denmark (wind) and Australia (solar PV) – can make outsize contributions. A carbon price ceiling is too low to drive innovation; generating carbon-reducing innovation requires that it be explicitly recognized as a priority, and nurtured accordingly: identify the priority area(s) where innovation at scale will be necessary to make progress; baseline the elements of the innovation ecosystem which are already in place, and the gaps that need to be filled. Key elements include institutions and incentives that promote innovation, a research and enterprise community that make it happen, and a supportive public.

This article explains why regulating autonomy in weapons systems, entailing the codification of a legally binding obligation to retain meaningful human control over the use of force, is such a challenging task within the framework of the United Nations Convention on Certain Conventional Weapons. It is difficult because it requires new diplomatic language, and because the military value of weapon autonomy is hard to forego in the current arms control winter. The article argues that regulation is nevertheless imperative, because the strategic as well as ethical risks outweigh the military benefits of unshackled weapon autonomy. To this end, it offers some thoughts on how the implementation of regulation can be expedited.