Affine T-varieties of complexity one and locally nilpotent derivations

Let X=spec A be a normal affine variety over an algebraically closed field k of characteristic 0 endowed with an effective action of a torus T of dimension n. Let also D be a homogeneous locally nilpotent derivation on the normal affine Z^n-graded domain A, so that D generates a k_+-action on X that is normalized by the T-action. We provide a complete classification of pairs (X,D) in two cases: for toric varieties (n=\dim X) and in the case where n=\dim X-1. This generalizes previously known results for surfaces due to Flenner and Zaidenberg. As an application we compute the homogeneous Makar-Limanov invariant of such varieties. In particular we exhibit a family of non-rational varieties with trivial Makar-Limanov invariant.Comment: 31 pages. Minor changes in the structure. Fixed some typo

Roots of the affine Cremona group

Let k[x_1,...,x_n] be the polynomial algebra in n variables and let A^n=Spec k[x_1,...,x_n]. In this note we show that the root vectors of the affine Cremona group Aut(A^n) with respect to the diagonal torus are exactly the locally nilpotent derivations x^a\times d/dx_i, where x^a is any monomial not depending on x_i. This answers a question due to Popov.Comment: 4 page

Est locus uni cuique suus: City and Status in Horace’s Satires 1.8 and 1.9

This is the published version

Eureka and beyond: mining's impact on African urbanisation

This collection brings separate literatures on mining and urbanisation together at a time when both artisanal and large-scale mining are expanding in many African economies. While much has been written about contestation over land and mineral rights, the impact of mining on settlement, notably its catalytic and fluctuating effects on migration and urban growth, has been largely ignored. African nation-states’ urbanisation trends have shown considerable variation over the past half century. The current surge in ‘new’ mining countries and the slow-down in ‘old’ mining countries are generating some remarkable settlement patterns and welfare outcomes. Presently, the African continent is a laboratory of national mining experiences. This special issue on African mining and urbanisation encompasses a wide cross-section of country case studies: beginning with the historical experiences of mining in Southern Africa (South Africa, Zambia, Zimbabwe), followed by more recent mineralizing trends in comparatively new mineral-producing countries (Tanzania) and an established West African gold producer (Ghana), before turning to the influence of conflict minerals (Angola, the Democratic Republic of Congo and Sierra Leone)

Corporate Social Responsibility and Sustainable Development Goal 9

With the spread of neoliberalism, corporate social responsibility (CSR) and private governance have become integral parts of corporate behavior. This entry discusses the aspects of Goal 9 (industry, innovation, and infrastructure) of the United Nations Sustainable Development Goals (SDGs) in relation to CSR. Goal 9 emphasizes sustainability, resilience, and equity of corporations, industries, and other social and economic actors in the processes of innovation and advancement of infrastructures. Although the concept of CSR, which represents positive social and environmental influences of corporations, is not explicitly mentioned in Goal 9, it is an important mechanism in accomplishing the objectives of the goal

Seeding Science, Courting Conclusions: Reexamining the Intersection of Science, Corporate Cash, and the Law

Social scientists have expressed strong views on corporate influences over science, but most attention has been devoted to broad, Black/White arguments, rather than to actual mechanisms of influence. This paper summarizes an experience where involvement in a lawsuit led to the discovery of an unexpected mechanism: A large corporation facing a multibillion-dollar court judgment quietly provided generous funding to well-known scientists (including at least one Nobel prize winner) who would submit articles to "open," peer-reviewed journals, so that their "unbiased science" could be cited in an appeal to the Supreme Court. On balance, the corporation's most effective techniques of influence may have been provided not by overt pressure, but by encouraging scientists to continue thinking of themselves as independent and impartial

“Working the System”—British American Tobacco's Influence on the European Union Treaty and Its Implications for Policy: An Analysis of Internal Tobacco Industry Documents

Katherine Smith and colleagues investigate the ways in which British American Tobacco influenced the European Union Treaty so that new EU policies advance the interests of major corporations, including those that produce products damaging to health