We show the thinness of $7$ of the $40$ hypergeometric groups having a maximally unipotent monodromy in $\mathrm{Sp}(6)$.

In this paper we produce infinite families of counterexamples to Jantzen's question posed in 1980 on the existence of Weyl $p$-filtrations for Weyl modules for an algebraic group and Donkin's tilting module conjecture formulated in 1990. New techniques to exhibit explicit examples are provided along with methods to produce counterexamples in large rank from counterexamples in small rank. Counterexamples can be produced via our methods for all groups other than when the root system is of type ${\rm A}_{n}$ or ${\rm B}_{2}$.

Following the introduction of the one-child policy in China, the capital-labor ratio of China increased relative to that of India, while FDI/GDP inflows to China versus India simultaneously declined. These observations are explained in the context of a simple neoclassical overlapping generations paradigm. The adjustment mechanism works as follows: the reduction in the growth rate of the (urban) labor force due to the one-child policy increases the capital per worker inherited from the previous generation. The resulting increase in China’s domestic capital-labor ratio thus "crowds out" the need for foreign direct investment (FDI) in China relative to India. Our paper is a contribution to the nascent literature exploring demographic transitions and their effects on FDI flows.

With the rise of deep reinforcement learning (RL) methods, many complex robotic manipulation tasks are being solved. However, harnessing the full power of deep learning requires large datasets. Online RL does not suit itself readily into this paradigm due to costly and time-consuming agent-environment interaction. Therefore, many offline RL algorithms have recently been proposed to learn robotic tasks. But mainly, all such methods focus on a single-task or multitask learning, which requires retraining whenever we need to learn a new task. Continuously learning tasks without forgetting previous knowledge combined with the power of offline deep RL would allow us to scale the number of tasks by adding them one after another. This paper investigates the effectiveness of regularisation-based methods like synaptic intelligence for sequentially learning image-based robotic manipulation tasks in an offline-RL setup. We evaluate the performance of this combined framework against common challenges of sequential learning: catastrophic forgetting and forward knowledge transfer. We performed experiments with different task combinations to analyse the effect of task ordering. We also investigated the effect of the number of object configurations and the density of robot trajectories. We found that learning tasks sequentially helps in the retention of knowledge from previous tasks, thereby reducing the time required to learn a new task. Regularisation-based approaches for continuous learning, like the synaptic intelligence method, help mitigate catastrophic forgetting but have shown only limited transfer of knowledge from previous tasks.

Qeltite (IMA2021–032), ideally Ca3Ti(Fe2Si)Si2O14, was found in gehlenite–rankinite–wollastonite paralava from a pyrometamorphic rock of the Hatrurim Complex at Nabi Musa locality, Judean Desert, West Bank, Palestine. It generally occurs as light-brown flattened crystals up to 40–50 μm in length and less than 5 μm in thickness. Its aggregates reach 100–200 μm in size. Its empirical crystal chemical formula based on 14 O is: (Ca2.96Sr0.02Mn0.01)Σ2.99Ti4+(Fe3+1.59Si0.60Al0.43Ti4+0.38Cr0.01)Σ3.01(Si1.99P0.01)Σ2O14. The strongest reflections in its calculated X-ray diffraction pattern are [d, Å, (I, %), hkl]: 3.12, (100), 111; 2.85, (61), 201; 2.85, (48), 021; 2.32, (45), 211; 6.93, (31), 100; and 1.81, (30), 212. Qeltite is trigonal and crystallises in the noncentrosymmetric P321 space group, with a = 8.0077(5) Å, c = 4.9956(4) Å, V = 277.42(4) Å3 and Z = 1. Its microhardness VHN25 is 708(17) kg/mm2 and its hardness on the Mohs scale is ~6. Its calculated density is 3.48 g/cm3. It was found in fine-grained mineral aggregates within coarse-grained main minerals of rankinite–gehlenite paralava with subordinate wollastonite, Ti-bearing andradite and kalsilite. In these aggregates, the mineral is associated with khesinite, paqueite and pseudowollastonite, indicating a high-temperature genesis (~1200°C). Its crystallisation can be compared with the crystallisation of minerals containing refractory inclusions in meteorites.

This article asks whether the abandonment of drifting fish aggregating devices (dFADs) is illegal under international marine pollution law. To answer this question, it provides a brief overview of the general international legal framework for the protection of the marine environment as well as specific legal regimes, namely the London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (LC), its 1996 Protocol (LP), and Annex V of the International Convention for the Prevention of Pollution from Ships (MARPOL). The article concludes that the abandonment of dFADs contravenes the LC/LP and/or, depending on the preferred interpretation, MARPOL Annex V. The decision as to which of the two regimes is applicable depends on whether dFAD abandonment can be classified as ‘incidental to, or derived from the normal operations of vessels … and their equipment’ or not. The negligent loss of dFADs always violates MARPOL Annex V. The article also shows that certain state practice and opinio juris suggests a parallel applicability of the two regimes with respect to deliberate dFAD abandonment. While such a development would ensure more comprehensive coverage of the relevant standards and prohibitions, a clear regulatory decision as to which of the two regimes is the correct one would be preferable from an implementation and enforcement perspective.

The aim of this article is to critically review the scientific literature about the changes in travel behaviour and mobility amongst older adults caused by the COVID-19 pandemic across various countries, identify unmet travel needs and highlight patterns of inequalities in older adults’ mobility. We have collected articles from four academic databases: PubMed, Scopus, Transportation Research International Documentation (TRID) and Web of Science. Papers were considered for inclusion if they were published online in 2020 or later, written in English, and referred to urban or rural changes in travel behaviour and mobility of older adults over 50 years old. We examined the pre-existing models developed before the outbreak and classified the articles based on Musselwhite and Haddad’s hierarchy of older adults’ travel needs. The synthesis of the selected 25 articles shows a general decline in literal mobility amongst older adults, an increased share of virtual travel and their decreased capacity to fulfil different levels of travel needs. Findings also indicate an increased gap in older adults’ mobility across geographical regions with various levels of transport infrastructure and digital capital. We conclude the paper with the lessons learned, the opportunities ahead, and the challenges that must be overcome to achieve sustainable development and the United Nations Decades of Healthy Ageing goals in the post-pandemic world.

Mantids are influential generalist predators in terrestrial systems. Therefore, large mantid species like the European mantid, Mantis religiosa (Linnaeus, 1758), are often used by humans and purposefully introduced as a form of biocontrol, greatly expanding their geographic ranges. However, mantids are rarely recorded in marine systems. In this study, we present an observation of European mantids living in a salt marsh and actively moulting in the vegetation in Elkhorn Slough, in Monterey Bay, California, United States of America. Not only are these European mantids a nonnative species, but every observed individual was a flightless juvenile, meaning they hatched nearby. Although mantids are not usually associated with intertidal ecosystems, there are multiple potential reasons that mantids would be drawn to salt marshes, including food, potential for camouflage, and lower predation pressure. The addition of a generalist predator could produce a complex mix of positive and negative impacts on the marsh itself and, given the importance of marsh systems, these possible effects warrant further study.

Qu, Dassios, and Zhao (2021) suggested an exact simulation method for tempered stable Ornstein–Uhlenbeck processes, but their algorithms contain some errors. This short note aims to correct their algorithms and conduct some numerical experiments.

A Microsoft® Visual Basic software, WinClbclas, has been developed to calculate the chemical formulae of columbite-supergroup minerals based on data obtained from wet-chemical and electron-microprobe analyses and using the current nomenclature scheme adopted by the Commission on New Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association (IMA) for columbite-supergroup minerals. The program evaluates 36 IMA-approved species, three questionable in terms of their unit-cell parameters, four insufficiently studied questionable species and one ungrouped species, all according to the dominant valance and constituent status in five mineral groups including ixiolite (MO2), wolframite (M1M2O4), samarskite (ABM2O8), columbite (M1M2O6) and wodginite (M1M2M32O8). Mineral compositions of the columbite supergroup are calculated on the basis of 24 oxygen atoms per formula unit. However, the formulae of the five ixiolite to wodginite groups can be estimated by the program on the basis of their cation and anion values in their typical mineral formulae (e.g. 4 cations and 8 oxygens for the wodginite group) with normalisation procedures. The Fe3+ and Fe2+ contents from microprobe-derived total FeO (wt.%) amounts are estimated by stoichiometric constraints. WinClbclas allows users to: (1) enter up to 47 input variables for mineral compositions; (2) type and load multiple columbite-supergroup mineral compositions in the data entry section; (3) edit and load the Microsoft® Excel files used in calculating, classifying, and naming the columbite-supergroup minerals, together with the total monovalent to hexavalent ion; and (4) store all the calculated parameters in the output of a Microsoft® Excel file for further data evaluation. The program is distributed as a self-extracting setup file, including the necessary support files used by the program, a help file and representative sample data files.