Stalling interkinetic nuclear migration in curved pseudostratified epithelium of developing cochlea

The bending of epithelial tubes is a fundamental process in organ morphogenesis, driven by various multicellular behaviours. The cochlea in the mammalian inner ear is a representative example of spiral tissue architecture where the continuous bending of the duct is a fundamental component of its morphogenetic process. Although the cochlear duct morphogenesis has been studied by genetic approaches extensively, it is still unclear how the cochlear duct morphology is physically formed. Here, we report that nuclear behaviour changes are associated with the curvature of the pseudostratified epithelium during murine cochlear development. Two-photon live-cell imaging reveals that the nuclei shuttle between the luminal and basal edges of the cell is in phase with cell-cycle progression, known as interkinetic nuclear migration, in the flat region of the pseudostratified epithelium. However, the nuclei become stationary on the luminal side following mitosis in the curved region. Mathematical modelling together with perturbation experiments shows that this nuclear stalling facilitates luminal-basal differential growth within the epithelium, suggesting that the nuclear stalling would contribute to the bending of the pseudostratified epithelium during the cochlear duct development. The findings suggest a possible scenario of differential growth which sculpts the tissue shape, driven by collective nuclear dynamics.

Perceptions and purpose of the bomb: Explaining India's nuclear restraint against China

Much of the literature on India's nuclear programme assumes that China's nuclear capability drove New Delhi, the strategically weaker actor, to pursue a nuclear weapons capability. China's nuclear tests not only rendered New Delhi militarily insecure and dented its claim for the leadership of the Third World but they also polarized the domestic debate over the utility of the bomb. In the global scheme of nuclear proliferation, therefore, India was just another fallen nuclear domino. Marshalling recently declassified documents, this article revisits India's nuclear behaviour during the crucial decade between 1964 and 1974. By focusing on threat assessments made at the highest levels and internal deliberations of the Indian Government, this article shows how, contrary to the claims made in the literature, Indian decision-makers did not make much of the Chinese nuclear threat. This conviction emanated out of their distinct reading of the purpose of nuclear weapons in China's foreign and military policy; their perceptions of how India could achieve nuclear deterrence against China by using the bipolar international politics of the Cold War; and, finally, their understanding of the political costs of developing an indigenous nuclear response to China's nuclear threat. New Delhi's nuclear restraint resulted from its perceptions of Chinese nuclear intentions and its beliefs about the purpose of the bomb in Sino-Indian relations. India's perceptions of China as a nuclear adversary and its decision-makers’ views on the purpose of nuclear weapons in this rivalry were fundamentally different from the expectations set out by the domino theory of nuclear proliferation.

The phylogenetic disposition of Antrodia s.l. (Polyporales, Basidiomycota) from Patagonia, Argentina

The aim of the present study was to characterise species of Antrodia s.l. from Patagonia, Argentina, and to determine their phylogenetic relationships by using morphological and cultural features as well as mating systems and ITS sequences. Phylogenetic trees generated from maximum-parsimony, neighbour-joining and Bayesian-inference analyses showed that the Argentinean collections were distributed inside the following three main clades: (1) ‘Antrodia clade’, with Antrodia ramentacea (Berk. & Broome) Donk as a sole representative; (2) ‘Amyloporia clade’, including Amyloporia nothofaginea Rajchenb. & Gorjón sp. nov. and A. stratosa (J.E.Wright & J.R.Deschamps) Rajchenb., Gorjón & Pildain comb. nov.; and (3) ‘Fibroporia clade’, with Fibroporia vaillantii (DC.) Parmasto and F. gossypium (Speg.) Parmasto. ‘Amyloporia’ and ‘Antrodia clades’ did not have strong molecular support; however, they were well defined with a polyphasic approach when other features such as the number of spore nuclei, mating systems and nuclear behaviour were added. Antrodia includes homothallic to bipolar species, with uni- or binucleate spores and normal nuclear behaviour. Amyloporia includes bipolar to tetrapolar species, with uninucleate spores and heterocytic nuclear behaviour. Fibroporia has strong molecular support and includes tetrapolar species, with uninucleate spores and normal nuclear behaviour. Amyloporia nothofaginea is described as a new species and two new combinations in Amyloporia are proposed. A key to the Antrodia s.l. species present in Patagonia is included.

The search for a scientific temper: nuclear technology and the ambivalence of India's postcolonial modernity

This article examines the relationship between India's nuclear programme and its postcolonial identity. In particular, I argue that making sense of the anomalies and contradictions of India's nuclear behaviour, such as the gap of two decades between its nuclear tests, its promotion of nuclear disarmament and its failure to sign non-proliferation and test-ban treaties requires an understanding of the racially gendered construction of India's postcolonial modernity and the central roles given to science and morality within it. I suggest that India's postcolonial identity is anchored in anticolonial discourses that are deeply ambivalent toward what was viewed as a Western modernity that could provide material betterment but was also potentially destructive. What was desired was a better modernity that took into account what was believed to be Indian civilisation's greater propensity toward ethical and moral conduct. India's nuclear policies, such as its pursuit of nuclear technology and its promotion of disarmament cannot be seen in isolation from the successes and failures of this broader project of fashioning an ethical modernity.