35 research outputs found
Disentangling participatory ICT design in socioeconomic development
Participatory design in socioeconomic development is an
invariably political activity fraught with both political as well as ethical entanglements. ICT for development (ICTD) - often involved in contexts of great inequality and heteogeneity - places these in especially sharp relief. This paper draws attention to these entanglements as well as what they mean for the role and practice of designer-researchers practicing PD. We then draw upon our experiences in an active PD project to highlight approaches that serve as a partial response to these entanglements. These presents both limitations as well as orientations for our role as designer-researchers in engaging with and organising PD work in ICTD - providing a starting point for answering the question “who participates with whom in what and why?
Francisella tularensis Peritonitis in Stomach Cancer Patient
Tularemia with peritonitis developed in a 50-year-old man soon after diagnosis of stomach cancer with metastasis. The ascites grew Francisella tularensis subsp. holarctica, which was identified by sequencing analysis of the 16S rDNA. The infection resolved with antimicrobial treatment. Antibodies detected 4 weeks after onset disappeared after chemotherapy-associated lymphopenia
Examining the generalizability of research findings from archival data
This initiative examined systematically the extent to which a large set of archival research findings generalizes across contexts. We repeated the key analyses for 29 original strategic management effects in the same context (direct reproduction) as well as in 52 novel time periods and geographies; 45% of the reproductions returned results matching the original reports together with 55% of tests in different spans of years and 40% of tests in novel geographies. Some original findings were associated with multiple new tests. Reproducibility was the best predictor of generalizability—for the findings that proved directly reproducible, 84% emerged in other available time periods and 57% emerged in other geographies. Overall, only limited empirical evidence emerged for context sensitivity. In a forecasting survey, independent scientists were able to anticipate which effects would find support in tests in new samples
The value of 18F-FDG PET before and after induction chemotherapy for the early prediction of a poor pathologic response to subsequent preoperative chemoradiotherapy in oesophageal adenocarcinoma
Elucidating the Electronic Structure of Transition Metal Complexes Featuring Redox Active Ligands
In this thesis a number of projects involving the design and characterization of complexes bearing redox active ligands are described. Focusing on the phenolate containing ligands, the properties and electronic structure of their corresponding metal complexes were studied by a series of experimental (i.e. electrochemistry, UV-Vis-NIR, EPR, rR etc.) and theoretical (DFT) methods. Specifically, the redox processes of these metal complexes were tuned by varying the para-ring substituents. In one study, nickel-salen (salen is a common abbreviation for N2O2 bis-Schiff-base bis-phenolate ligands) complexes were investigated, where the oxidation potentials of the ligand were predictably decreased as the electron donating ability of the para-ring substituents was increased (NMe2 > OMe > tBu > CF3). Interestingly, the oxidation of these geometrically-symmetric complexes afforded an asymmetric electronic structure in a number of cases, in which the ligand radical was localized on one phenolate rather than delocalized across the ligand framework. This difference in electronic structure was found to be dependent on the electron donating ability of the substituents; a delocalized ligand radical was observed for electron-withdrawing substituents and a localized ligand radical for strongly donating substituents. These studies highlight that para-ring substituents can be used to tune the electronic structure (metal vs. ligand based, localized vs. delocalized radical character) of metallosalen complexes. To evaluate if this electronic tuning can be applied to the metal center, a series of cobalt complexes of these salen ligands were prepared. Indeed, the electronic properties of the metal center were also significantly affected by para-ring substitution. These cobalt-salen complexes were tested as catalysts in organometallic radical-mediated polymerizations, where the most electron rich complexes displayed the best conversion rates. With a firm understanding of the role that the para-ring substituent can play in influencing the electronic structure and reactivity of metallosalen complexes in catalysis, two novel iron complexes, which contain a number of redox active phenolate fragments, were prepared. In addition, these iron-complexes feature a chiral bipyrrolidine backbone. Ligands with this chiral diamine backbone bind metals ions diastereoselectively owing to its increased rigidity, which is critical to stereoselectivity in catalysis. A symmetric (with two phenolates) ligand was prepared by reported methods, and a novel route to synthesize an asymmetric ligand (one phenolate and one pyridine) from symmetric starting materials was established. The neutral iron-complexes were found to be high spin (S = 5/2), and can undergo ligand based oxidation to form an antiferromagnetically-coupled (Stotal = 2) species. The results presented will serve as the basis for catalyst development using complexes of similar ligands
Realisation of quantum entanglement and chaos in gravity
Originating from string theory, the holographic correspondence provides a dictionary to convert a quantum theory on the boundary of the Anti-deSitter space (AdS) into a theory of gravity in the bulk AdS space. In this thesis we will study the intersection of quantum information and quantum gravity, focusing on methods of quantifying quantum entanglement and chaos in gravity via the AdS/CFT holographic correspondence. Entanglement entropy of a bipartite quantum system on the boundary is equivalent to the area of a minimal surface in the bulk. In both the boundary and bulk pictures, entanglement entropy is divergent, meaning it equals to infinity. Hence we need to renormalise the entanglement entropy to obtain a finite quantity. The variation of the entanglement entropy is related to the dynamics of the bulk spacetime via the first law of entanglement entropy. We will first present a way to express the renormalised entanglement entropy in terms of the Euler invariant of the bulk entangling surface and other renormalised curvature invariants. Then we use this expression and independently derived the renormalised version of the first law of entanglement entropy. In particular, we use the Hamiltonian formalism of holographic renormalisation to derive the integral form of the first law of entanglement entropy. Quantum chaos is characterised by the scrambling of information that increases exponentially in time. The rate of the exponential growth, known as the Lyapunov exponent, can be measured via the out-of-time-ordered correlation function (OTOC). In holography, the OTOC becomes the gravitational scattering amplitude of high energy particles. We investigate a possible correction to the Lyapunov exponent by considering the classical stringy effect in the bulk gravitational scattering. Following the semi-classical shock wave calculation of gravitational eikonal scattering, we obtain the classical string transverse oscillation contribution to the eikonal phase. We conclude such correction is negligible in the high energy eikonal limit, hence satisfying the chaos bound
Renormalized entanglement entropy and curvature invariants
Renormalized entanglement entropy can be defined using the replica trick for any choice of renormalization scheme; renormalized entanglement entropy in holographic settings is expressed in terms of renormalized areas of extremal surfaces. In this paper we show how holographic renormalized entanglement entropy can be expressed in terms of the Euler invariant of the surface and renormalized curvature invariants. For a spherical entangling region in an odd-dimensional CFT, the renormalized entanglement entropy is proportional to the Euler invariant of the holographic entangling surface, with the coefficient of proportionality capturing the (renormalized) F quantity. Variations of the entanglement entropy can be expressed elegantly in terms of renormalized curvature invariants, facilitating general proofs of the first law of entanglement