324 research outputs found

    Historical biogeography of Melastomataceae

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    Melastomataceae and Memecylaceae are pantropically distributed sister groups for which an ndhF gene phylogeny for 91 species in 59 genera is here linked with Eurasian and North American fossils in a molecular clock approach to biogeographical reconstruction. Nine species from the eight next-closest families are used to root phylogenetic trees obtained under maximum likelihood criteria. Melastomataceae comprise ∼3000 species in the neotropics, ∼1000 in tropical Asia, 240 in Africa, and 225 in Madagascar in 150-166 genera, and the taxa sampled come from throughout this geographic range. Based on fossils, ranges of closest relatives, tree topology, and calibrated molecular divergences, Melastomataceae initially diversified in Paloecene/Eocene times in tropical forest north of the Tethys. Their earliest (Eocene) fossils are from northeastern North America, and during the Oligocene and Miocene melastomes occurred in North America as well as throughout Eurasia. They also entered South America, with earliest (Oligocene) South American fossils representing Merianieae. One clade (Melastomeae) reached Africa from the neotropics 14-12 million years ago and from there spread to Madagascar, India, and Indochina. Basalmost Melastomataceae (Kibessieae, Astronieae) are species-poor lineages restricted to Southeast Asia. However, a more derived Asian clade (Sonerileae/Dissochaeteae) repeatedly reached Madagascar and Africa during the Miocene and Pliocene. Contradicting earlier hypotheses, the current distribution of Melastomataceae is thus best explained by Neogene long-distance dispersal, not Gondwana fragmentation

    Continuity of the von Neumann entropy

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    A general method for proving continuity of the von Neumann entropy on subsets of positive trace-class operators is considered. This makes it possible to re-derive the known conditions for continuity of the entropy in more general forms and to obtain several new conditions. The method is based on a particular approximation of the von Neumann entropy by an increasing sequence of concave continuous unitary invariant functions defined using decompositions into finite rank operators. The existence of this approximation is a corollary of a general property of the set of quantum states as a convex topological space called the strong stability property. This is considered in the first part of the paper.Comment: 42 pages, the minor changes have been made, the new applications of the continuity condition have been added. To appear in Commun. Math. Phy

    Innovation and HRM : absences and politics

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    This article analyses the role of HRM practices in the implementation of an innovative cross-functional approach to new product development (concurrent engineering, CE) in Eurotech Industries. Contrary to CE methodology stipulations, and despite supportive conditions, HRM received scant attention in the implementation process. Organizational power and politics were clearly involved in this situation, and this article explores how their play created such HRM &lsquo;absences&rsquo;. The article builds on a four-dimensional view of power in order to provide a deeper understanding of the embedded, interdependent and political nature of HRM practice and innovation.<br /

    The New Politics of Global Tax Governance: Taking Stock a Decade After the Financial Crisis

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    The financial crisis of 2007–2009 is now broadly recognised as a once-in-a-generation inflection point in the history of global economic governance. It has also prompted a reconsideration of established paradigms in international political economy (IPE) scholarship. Developments in global tax governance open a window onto these ongoing changes, and in this essay we discuss four recent volumes on the topic drawn from IPE and beyond, arguing against an emphasis on institutional stability and analyses that consider taxation in isolation. In contrast, we identify unprecedented changes in tax cooperation that reflect a significant contemporary reconfiguration of the politics of global economic governance writ large. To develop these arguments, we discuss the links between global tax governance and four fundamental changes underway in IPE: the return of the state through more activist policies; the global power shift towards large emerging markets; the politics of austerity and populism; and the digitalisation of the economy

    Corporation tax as a problem of MNC organisational circuits: The case for unitary taxation

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    The tax practices of multinational corporations have become a matter of significant public and political concern. The underlying issues are rooted in the capacity of multinational corporations (MNCs) to construct organisational circuits that shift where sales, revenue and profit are reported. This capacity in turn becomes a focus because of the way MNCs are treated as a series of separate entities, subject to the arm’s length principle. This has become a classic example of a system whose current form and consequences were not foreseen when the original principles were set out. The continued existence of that system owes more to specific interests and inertia than it does to the absence of a viable alternative. Unitary taxation based on formula apportionment clearly resolves the underlying issues and unitary taxation may well ultimately emerge as a new generalised basis for corporate taxation. However, for it to do so, the problems of the current system and the advantages of the alternative need to be more clearly understood within academia, business and on a societal basis. This paper is a contribution to such an understanding

    Nanofluidic transport governed by the liquid/vapour interface

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    Liquid/vapour interfaces govern the behaviour of a wide range of systems but remain poorly understood, leaving ample margin for the exploitation of intriguing functionalities for applications. Here, we systematically investigate the role of liquid/vapour interfaces in the transport of water across apposing liquid menisci in osmosis membranes comprising short hydrophobic nanopores that separate two fluid reservoirs. We show experimentally that mass transport is limited by molecular reflection from the liquid/vapour interface below a certain length scale, which depends on the transmission probability of water molecules across the nanopores and on the condensation probability of a water molecule incident on the liquid surface. This fundamental yet elusive condensation property of water is measured under near-equilibrium conditions and found to decrease from 0.36 ± 0.21 at 30 °C to 0.18 ± 0.09 at 60 °C. These findings define the regime in which liquid/vapour interfaces govern nanofluidic transport and have implications for understanding mass transport in nanofluidic devices, droplets and bubbles, biological components and porous media involving liquid/vapour interfaces.Center for Clean Water and Clean Energy at MIT and KFUPM (Project R10-CW-09

    Central banking and inequalities: taking off the blinders

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    What is the relation between monetary policy and inequalities in income and wealth? This question has received insufficient attention, especially in light of the unconventional policies introduced since the 2008 financial crisis. The article analyzes three ways in which the concern central banks show for inequalities in their official statements remains incomplete and underdeveloped. First, central banks tend to care about inequality for instrumental reasons only. When they do assign intrinsic value to containing inequalities, they shy away from trade-offs with the standard objectives of monetary policy that such a position entails. Second, central banks play down the causal impact monetary policy has on inequalities. When they do acknowledge it, they defend their actions by claiming that it is an unintended side effect, that it is temporary, and/or that any alternative policy would fare even worse. The article appeals to the doctrine of double effect to criticize these arguments. Third, even if one accepts that inequalities should be contained and that today’s monetary policies exacerbate them, is it both desirable and feasible to make containing inequalities part of the mandate of central banks? The article analyzes and rejects three attempts on the part of central banks to answer this question negatively
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