Central Limit Results for Jump-Diffusions with Mean Field Interaction and a Common Factor

A system of $N$ weakly interacting particles whose dynamics is given in terms of jump-diffusions with a common factor is considered. The common factor is described through another jump-diffusion and the coefficients of the evolution equation for each particle depend, in addition to its own state value, on the empirical measure of the states of the $N$ particles and the common factor. A Central Limit Theorem, as $N \to \infty$, is established. The limit law is described in terms of a certain Gaussian mixture. An application to models in Mathematical Finance of self-excited correlated defaults is described

Neutral low-dimensional assemblies of a Mn(III) schiff base complex and octacyanotungstate(V) : synthesis, characterization, and magnetic properties

International audienceTwo novel low-dimensional molecular magnetic materials were prepared by the self-assembly of 3d- and 5d-metal complexes. These are the first neutral heterobimetallic cyanobridged compounds involving one anisotropic Mn(III) Schiff base complex and one octacyanotungstate(V) per molecular unit. A slow diffusion of the constituents’ solutions leads to the formation of the 0D crystalline complex 1, due to coordination of a water molecule to the Mn center, which prevents polymer formation. A rapid mixing of reagents results in the precipitation of the microcrystalline powder of complex 2, which based on the totality of experimental data, possesses a 1D polymeric structure. The magnetic studies have shown that antiferromagnetic exchange interactions prevail in 1 (J/kB = −13.1(7) K, D = −3.0(1.3) K, zJ' = −0.16(20) K and gav = 2.00(1)); while the presence of the significant intramolecular Mn(III)–W(V) ferromagnetic coupling through cyanide bridge is characteristic for 2 (J/kB = 46.1(5) K, gMn = 2.11(3), fixed gW = 2.0). Due to the weak interchain interactions, zJ′/kB = −0.8(2) K, and compound 2 is a metamagnet with the Néel temperature of 9.5 K undergoing a spin-flip transition at 2 kOe. The slow magnetization dynamics of 2 were investigated at a DC field of 0 and 2 kOe, giving the values of τ0 32(15) and 36(15) ps, respectively, well within the range typical for single-chain magnets (SCMs). The respective ∆τ/kB values were 48.4(1.2) and 44.9(1.0) K

Investing in Innovation: Evidence from the Pharmaceutical Industry

This dissertation explores the role that organizations play in bringing scientific innovations to society. Chapter 1 situates this work in the current landscape of innovation research and motivates the need for further research on this topic. Chapter 2 explores the role thatfailure, both technological and regulatory, plays in understanding how organizations make future investments in innovative projects. I find that following FDA rejection, biopharmaceutical firms become significantly less likely to further invest in unrelated products already under development. However, they experience a higher proportion of future successes, as they redirect investment into less risky innovations. In contrast, I find no evidence of these effects in response to technological failures at the end of clinical trials, suggesting that this effect is not driven by the loss of firm value nor does it support a traditional Bayesian updating framework. Rather, these findings are consistent with the idea that there is a difference between failure at the technological level versus failure at the decision making level.Chapter 3 illustrates how the boundaries of an organization influence the type of innovations in which organizations do and not choose to invest following a sudden reshuffling of consumer demand. I demonstrate that a sudden increase in market size (and therefore expected revenue) increases an established firm’s propensity to make larger investments in products in their pipeline that are less likely to receive approval. However, I find that this result only holds for those organizations that diversify into fewer therapeutic spaces and are additionally more centralized. I theorize that, in line with findings from organizational economics and internal capital allocation inefficiency, this is due to management having greater control over resource allocation decisions in more centralized firms.Finally, Chapter 4 studies how the type of innovation pursued may affect market outcomes and competitive interactions between organizations. Using drug repurposing as a research context, I explore how the repurposing of a pharmaceutical drug for a new disease impacts its sales, and the sales of its competitors, for other approved uses. By leveraging variation in the combination of diseases that one drug treats and the timing of those disease approvals, I find a positive spillover effect of repurposing on sales of the drug for other diseases and this effect also spills over into the drug’s close competitors. Furthermore, I find that this growth in sales comes at the expense of competitors further away in therapeutic type. These findings have important implications for a pharmaceutical firm’s R&D strategy and the strategic responses to be made by competitors

Whitewater Ecotourism Development In Bhutan: Opportunities And Challenges for Local Communities

Whitewater raft and kayak ecotourism can provide environmental, social-cultural, and economic benefits and opportunities to local communities, but can also result in respective challenges. Globally, adventure ecotourism is seen as a potent win-win strategy for conservation and local community development; however, there is a significant proportion of adventure and whitewater tourism that do not meet ecotourism tenets, and there is a call for incorporating greater investment in local community involvement. Whitewater ecotourism is particularly significant because of the unique opportunities and challenges associated with rivers, the resource upon which the industry directly depends. Clean, free-flowing rivers provide a range of crucial ecosystem services, but are simultaneously experiencing rampant threats to existence, such as widespread large-scale hydropower development and increases in waste. Worldwide there is a call for growing local, national, and international efforts to address these threats. In Bhutan, a Himalayan Buddhist kingdom with a small but growing whitewater ecotourism industry, proposals for large-scale hydropower development and growing amounts of trash are changing Bhutan’s rivers and communities, yet there has been little research conducted on impacts of whitewater ecotourism related to communities and rivers in Bhutan.Through a case study in Panbang, Bhutan with the community-based raft company River Guides of Panbang, this research applies a qualitative methods approach to explore whitewater ecotourism related opportunities and challenges for local communities. The findings offer unique aspects of whitewater ecotourism in Bhutan; perceived opportunities, constraints, and constraint negotiations to increase women’s participation in whitewater ecotourism as river guides; and opportunities for the whitewater ecotourism industry in Panbang to engage in addressing Bhutan’s river threats of hydropower development and waste management. These outcomes provide a foundational understanding for specific benefits and constraints associated with whitewater ecotourism in Panbang, Bhutan that can inform sustainable tourism planning for whitewater ecotourism and river conservation initiatives at the local and national scale

Erythrocytes in multiple sclerosis: forgotten contributors to the pathophysiology?

Multiple sclerosis (MS) is an autoimmune disease characterised by lymphocytic infiltration of the central nervous system and subsequent destruction of myelin and axons. On the background of a genetic predisposition to autoimmunity, environmental triggers are assumed to initiate the disease. The majority of MS research has focused on the pathological involvement of lymphocytes and other immune cells, yet a paucity of attention has been given to erythrocytes, which may play an important role in MS pathology. The following review briefly summarises how erythrocytes may contribute to MS pathology through impaired antioxidant capacity and altered haemorheological features. The effect of disease-modifying therapies on erythrocytes is also reviewed. It may be important to further investigate erythrocytes in MS, as this could broaden the understanding of the pathological mechanisms of the disease, as well as potentially lead to the discovery of novel and innovative targets for future therapies

Lattices of quasi-equational theories as congruence lattices of semilattices with operators, Part I

We show that for every quasivariety K of structures (where both functions and relations are allowed) there is a semilattice S with operators such that the lattice of quasi-equational theories of K (the dual of the lattice of sub-quasivarieties of K) is isomorphic to Con(S,+,0,F). As a consequence, new restrictions on the natural quasi-interior operator on lattices of quasi-equational theories are found.Comment: Presented on International conference "Order, Algebra and Logics", Vanderbilt University, 12-16 June, 2007 25 pages, 2 figure