Higher dimensional foliated Mori theory

We develop some basic results in a higher dimensional foliated Mori theory, and show how these results can be used to prove a structure theorem for the Kleiman-Mori cone of curves in terms of the numerical properties of $K_{\mathcal{F}}$ for rank 2 foliations on threefolds. We also make progress toward realizing a minimal model program for rank 2 foliations on threefolds.Comment: 50 pages, new version taking into account referee suggestions, published version to appear in Compositio Mat

On the Mechanical Energy Available to Drive Solar Flares

Where does solar flare energy come from? More specifically, assuming that the ultimate source of flare energy is mechanical energy in the convection zone, how is this translated into energy dissipated or stored in the corona? This question appears to have been given relatively little thought, as attention has been focussed predominantly on mechanisms for the rapid dissipation of coronal magnetic energy by way of MHD instabilities and plasma micro instabilities. We consider three types of flare theory: the steady state "photospheric dynamo" model in which flare power represents coronal dissipation of currents generated simultaneously by sub-photospheric flows; the "magnetic energy storage" model where sub-photospheric flows again induce coronal currents but which in this case are built up over a longer period before being released suddenly; and "emerging flux" models, in which new magnetic flux rising to the photosphere already contains free energy, and does not require subsequent stressing by photospheric motions. We conclude that photospheric dynamos can power only very minor flares; that coronal energy storage can in principle meet the requirements of a major flare, although perhaps not the very largest flares, but that difficulties in coupling efficiently to the energy source may limit this mechanism to moderate sized flares; and that emerging magnetic flux tubes, generated in the solar interior, can carry sufficient free energy to power even the largest flares ever observed.Comment: 14 pages, 1 figur

<i>Aporosa</i> Blume from the paleoequatorial rainforest of Bikaner, India: Its evolution and diversification in deep time

The Gondwanan origin, northward migration and subsequent collision with Asia means that the Indian subcontinent is of particular interest regarding the origin and dispersal of numerous plants and animal species. With this in mind, we describe a fossil leaf of Aporosa Blume (Phyllanthaceae) from the Paleogene of the Indian subcontinent and discuss its evolution and diversification with respect to the moving Indian plate and its connection with Southeast Asia since the early Cenozoic. At present, Aporosa Blume is confined to Southeast Asia with a few species in India and New Guinea. It is represented by six endemic species growing in the evergreen forests of India and Sri Lanka, including Aporosa acuminata Thwaites, which is morphologically close to the here described fossil from Bikaner, Rajasthan, India. From the age of the fossil and the distribution of its modern comparable form, it is assumed that Aporosa originated on the Indian subcontinent and then was distributed to Southeast Asia, supporting the ‘Out of India’ hypothesis. Diversification of the genus might have taken place either in the Paleogene or Neogene. Our fossil leaf material also indicates the existence of palaeoequatorial (< 10° N) tropical rain forests in western India during the Paleogene in contrast to dry and desertic climate occurring today

Occurrence of <i>Shorea</i> Roxburgh ex C. F. Gaertner (Dipterocarpaceae) in the Neogene Siwalik forests of eastern Himalaya and its biogeography during the Cenozoic of Southeast Asia

We report the occurrence of two leaf impressions and one leaf compression along with one winged fruit and two fruiting calyx lobes, resembling those of Shorea Roxburgh ex C. F. Gaertner, in the lower Siwalik (Dafla Formation, middle to upper Miocene), middle Siwalik (Subansiri Formation, Pliocene) and upper Siwalik (Kimin Formation, upper Pliocene to lower Pleistocene) sediments exposed in Arunachal Pradesh, eastern Himalaya. We determine their taxonomic positions based on morphological comparison with similar extant and fossil specimens and discuss their phytogeographic and paleoclimatic implications in terms of the distribution and habitat of fossil and modern populations. The Miocene winged fruit is recognized as Shorea pinjoliensis Khan, R.A. Spicer et Bera, sp. nov. while the Pliocene and Plio-Pleistocene fruiting calyx lobes are recognized as Shorea bhalukpongensis Khan, R.A. Spicer et Bera, sp. nov. and Shorea chandernagarensis Khan, R.A. Spicer et Bera, sp. nov. respectively. Based on leaf architecture the Miocene, Pliocene and Plio-Pleistocene leaves are recognized as Shorea mioobtusa Khan, R.A. Spicer et Bera, sp. nov., Shorea pliotumbuggaia Khan, R.A. Spicer et Bera, sp. nov. and Shorea nepalensis Konomatsu et Awasthi respectively. The discovery of members of Shorea indicates that they had arrived in a tropical, warm and humid eastern Himalaya by the Mio-Pleistocene. Present and earlier records of Shorea suggest that this genus was a common forest element during Neogene (Miocene time) as well as in the Siwalik forests including Arunachal sub-Himalaya. In this paper, we also review in detail the biogeographic history and suggest possible migration routes of the genus

Reconstructing Cenozoic vegetation from proxy data and models – A NECLIME synthesis (Editorial)

[No abstract available

Institutional Technology and the Chains of Trust: Capital Markets and Privatization in Russia and the Czech Republic

The introduction of mass privatization policies in Russia and the Czech Republic depended on the creation of impersonal capital markets to finance the needs of privatized companies and to provide a secondary market for the trading of securities. Yet, mass privatization created the contradictory conditions of generating millions of poorly informed shareholders, with no efficient markets for the sale of the shares. The absence of financial markets created systematic pressures to move assets by illegal or non-transparent means to users who value them. Privatization created the incentives to destroy the financial markets critical to its success. A comparative case analysis of post-privatization market formation in both these countries demonstrates that the functional necessity for these markets does not engender their own creation. In the absence of institutional mechanisms of state regulation and trust, markets become arenas for political contests and economic manipulation. The irony of these policies is that a principal lesson has been that market reforms cannot create viable markets, only institutional formation can.http://deepblue.lib.umich.edu/bitstream/2027.42/39719/3/wp335.pd

Walmart\u27s Sustainability Journey: Lee Scott\u27s Founding Vision

The first case—“Lee Scott’s Founding Vision”—takes the perspective from the apex of the organization as Walmart’s CEO, Lee Scott, develops and articulates his vision of what Walmart hopes to achieve by pursuing an aggressive sustainability strategy. This case explores the pressures that led Scott to announce the company’s ambitious sustainability goals: achieving zero waste, 100% renewable energy, and selling sustainable products. It also explores the choices made when defining and communicating the scope of the strategy, particularly through an in-depth analysis of his announcement of Walmart’s new goals in his October 2005, “Twenty-First Century Leadership” speech

INSTITUTIONS AND THE VICIOUS CIRCLE OF DISTRUST IN THE RUSSIAN HOUSEHOLD DEPOSIT MARKET, 1992-1999

In our analysis of the Russian household deposit market during the 1990s, we show how the initial conditions of market emergence contributed to a vicious circle in which private commercial banks progressively lost the trust of potential depositors. The roots of this destructive dynamic lay in the initial conditions of market emergence. Initial experiences of fraud and financial loss led Russian households to distrust that commercial banks would honor their contractual obligations. As distrust grew and became more ingrained, the competitive conditions in the deposit market changed in a way that further increased the gains to opportunism and decreased the returns to trust production. In a self-reinforcing process, fraud begat more fraud.http://deepblue.lib.umich.edu/bitstream/2027.42/39974/3/wp588.pd