1,010 research outputs found

    The Role of Narrative Fiction and Semi-Fiction in Organizational Studies

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    In this chapter, we discuss the use of narrative fiction and semi-fiction in organizational research and explore the strengths and weaknesses of these alternative approaches. We begin with an introduction reviewing the existing literature and clarifying what we mean by fiction and semi-fiction. We then present and discuss examples of fiction and semi-fiction focusing on how these approaches can be used in organizational research. We argue that fiction is more useful as a source of data and as a way of representing theory to an audience. Semi-fiction, on the other hand, provides a novel approach to the production and representation of theory. In both cases, researchers face a number of challenges, but also gain access to new and powerful techniques for developing insights into organizational topics

    Generating Non-Linear Interpolants by Semidefinite Programming

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    Interpolation-based techniques have been widely and successfully applied in the verification of hardware and software, e.g., in bounded-model check- ing, CEGAR, SMT, etc., whose hardest part is how to synthesize interpolants. Various work for discovering interpolants for propositional logic, quantifier-free fragments of first-order theories and their combinations have been proposed. However, little work focuses on discovering polynomial interpolants in the literature. In this paper, we provide an approach for constructing non-linear interpolants based on semidefinite programming, and show how to apply such results to the verification of programs by examples.Comment: 22 pages, 4 figure

    Measurements of Ice Shelf Water beneath the front of the Ross Ice Shelf using gliders

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    Measurements made by an underwater glider deployed near the Ross Ice Shelf were used to identify the presence of Ice Shelf Water (ISW), which is defined as seawater with its potential temperature lower than its surface freezing point temperature. Properties logged by the glider included in situ temperature, electrical conductivity, pressure, GPS location at surfacings and time. For most of the first 30 recorded dives of its deployment, evidence suggests the glider was prevented from surfacing due to being under the ice shelf. For dives under the ice shelf, farthest from the ice shelf front, ISW layers of varying thicknesses and depth locations were observed; between 2 m thick (centred at 231 m depth) to >93 m thick (centred at >360 m). For dives under the ice shelf, close to the ice shelf front, either no ISW was observed or ISW layers were centred at shallower depths (116–127 m). Thicker ISW layers (e.g. up to 250 m thickness centred at 421 m) were observed for some glider dives in open water in front of the Ross Ice Shelf. No in situ supercooling (water colder than the pressure-dependent freezing point temperature) was observed

    Liquidity, technological opportunities, and the stage distribution of venture capital investments

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    This paper explores the determinants of the stage distribution of European venture capital investments from 1990 to 2011. Consistent with liquidity risk theory, we find that the likelihood of investing in earlier stages increases relative to all private equity investments during liquidity crisis years. While liquidity is the main driver of acquisition investments and, to some extent, of expansion financings, technological opportunities are overall the main driver of early and late stage venture capital investments. In contrast to the dotcom crash, the recent financial crisis negatively affected the relative likelihood of expansion investments, but not of early and late stage investments

    The Muonium Atom as a Probe of Physics beyond the Standard Model

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    The observed interactions between particles are not fully explained in the successful theoretical description of the standard model to date. Due to the close confinement of the bound state muonium (M=μ+eM = \mu^+ e^-) can be used as an ideal probe of quantum electrodynamics and weak interaction and also for a search for additional interactions between leptons. Of special interest is the lepton number violating process of sponteanous conversion of muonium to antimuonium.Comment: 15 pages,6 figure

    Spin-dynamics simulations of the triangular antiferromagnetic XY model

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    Using Monte Carlo and spin-dynamics methods, we have investigated the dynamic behavior of the classical, antiferromagnetic XY model on a triangular lattice with linear sizes L300L \leq 300. The temporal evolutions of spin configurations were obtained by solving numerically the coupled equations of motion for each spin using fourth-order Suzuki-Trotter decompositions of exponential operators. From space- and time-displaced spin-spin correlation functions and their space-time Fourier transforms we obtained the dynamic structure factor S(q,w)S({\bf q},w) for momentum q{\bf q} and frequency ω\omega. Below TKTT_{KT}(Kosterlitz-Thouless transition), both the in-plane (SxxS^{xx}) and the out-of-plane (SzzS^{zz}) components of S(q,ω)S({\bf q},\omega) exhibit very strong and sharp spin-wave peaks. Well above TKTT_{KT}, SxxS^{xx} and SzzS^{zz} apparently display a central peak, and spin-wave signatures are still seen in SzzS^{zz}. In addition, we also observed an almost dispersionless domain-wall peak at high ω\omega below TcT_{c}(Ising transition), where long-range order appears in the staggered chirality. Above TcT_{c}, the domain-wall peak disappears for all qq. The lineshape of these peaks is captured reasonably well by a Lorentzian form. Using a dynamic finite-size scaling theory, we determined the dynamic critical exponent zz = 1.002(3). We found that our results demonstrate the consistency of the dynamic finite-size scaling theory for the characteristic frequeny ωm\omega_{m} and the dynamic structure factor S(q,ω)S({\bf q},\omega) itself.Comment: 8 pages, RevTex, 10 figures, submitted to PR

    Renormalization-Group Improved Effective Potential for Interacting Theories with Several Mass Scales in Curved Spacetime

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    The renormalization group (RG) is used in order to obtain the RG improved effective potential in curved spacetime. This potential is explicitly calculated for the Yukawa model and for scalar electrodynamics, i.e. theories with several (namely, more than one) mass scales, in a space of constant curvature. Using the λφ4\lambda \varphi^4-theory on a general curved spacetime as an example, we show how it is possible to find the RG improved effective Lagrangian in curved spacetime. As specific applications, we discuss the possibility of curvature induced phase transitions in the Yukawa model and the effective equations (back-reaction problem) for the λφ4\lambda \varphi^4-theory on a De Sitter background.Comment: 18 pages, LaTeX file, UB-ECM-PF 93/2

    Identifying New Sources of Resistance to Brown Stem Rot in Soybean

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    Brown stem rot (BSR), caused by the fungus Phialophora gregata f. sp. sojae (Allington & D.W. Chamberlain) W. Gams (syn. Cadophora gregata), causes yield losses up to 38%. Three dominant BSR-resistant genes have been identified: Rbs1, Rbs2, and Rbs3. Additional BSR resistance loci will complement breeding efforts by expanding the soybean [Glycine max (L.) Merr.] genetic base. The objective of this research was to determine if PI 594637, PI 594638B, PI 594650A, and PI 594858B contained novel BSR resistance genes. The accessions were crossed to three genotypes with known BSR resistance genes and populations were developed for allelism studies. A minimum of 60 F2:3 families tracing to individual F2 plants in each population were used, and six seeds from each F2:3 family were tested. Resistant and susceptible controls and parents were also included. The BSR symptoms were assessed under growth chamber conditions 5 wk after inoculation by measuring foliar and stem severities and recovery of P. gregata from stem sections. Allelism tests of F2:3 plants from crosses of PI 594638B, PI 594858B, and PI 594650A with the resistant sources fit a 15:1 ratio, indicating that the resistant gene possessed by each of the PIs was nonallelic to Rbs1, Rbs2, and Rbs3. The three PIs contain at least one novel BSR resistance gene and have the potential to serve as donors to elite germplasm, increasing stability of host resistance to P. gregata. Allelism tests of PI 594637 segregated in a 3:1 ratio and no significant difference was found between PI 594637 and the susceptible controls, indicating that PI 594637 is susceptible to BSR

    Heat release by controlled continuous-time Markov jump processes

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    We derive the equations governing the protocols minimizing the heat released by a continuous-time Markov jump process on a one-dimensional countable state space during a transition between assigned initial and final probability distributions in a finite time horizon. In particular, we identify the hypotheses on the transition rates under which the optimal control strategy and the probability distribution of the Markov jump problem obey a system of differential equations of Hamilton-Bellman-Jacobi-type. As the state-space mesh tends to zero, these equations converge to those satisfied by the diffusion process minimizing the heat released in the Langevin formulation of the same problem. We also show that in full analogy with the continuum case, heat minimization is equivalent to entropy production minimization. Thus, our results may be interpreted as a refined version of the second law of thermodynamics.Comment: final version, section 2.1 revised, 26 pages, 3 figure
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