Investment under ambiguity with the best and worst in mind

Recent literature on optimal investment has stressed the difference between the impact of risk and the impact of ambiguity - also called Knightian uncertainty - on investors' decisions. In this paper, we show that a decision maker's attitude towards ambiguity is similarly crucial for investment decisions. We capture the investor's individual ambiguity attitude by applying alpha-MEU preferences to a standard investment problem. We show that the presence of ambiguity often leads to an increase in the subjective project value, and entrepreneurs are more eager to invest. Thereby, our investment model helps to explain differences in investment behavior in situations which are objectively identical

A self-consistent perturbative evaluation of ground state energies: application to cohesive energies of spin lattices

The work presents a simple formalism which proposes an estimate of the ground state energy from a single reference function. It is based on a perturbative expansion but leads to non linear coupled equations. It can be viewed as well as a modified coupled cluster formulation. Applied to a series of spin lattices governed by model Hamiltonians the method leads to simple analytic solutions. The so-calculated cohesive energies are surprisingly accurate. Two examples illustrate its applicability to locate phase transition.Comment: Accepted by Phys. Rev.

Electron spin relaxation by nuclei in semiconductor quantum dots

We have studied theoretically the electron spin relaxation in semiconductor quantum dots via interaction with nuclear spins. The relaxation is shown to be determined by three processes: (i) -- the precession of the electron spin in the hyperfine field of the frozen fluctuation of the nuclear spins; (ii) -- the precession of the nuclear spins in the hyperfine field of the electron; and (iii) -- the precession of the nuclear spin in the dipole field of its nuclear neighbors. In external magnetic fields the relaxation of electron spins directed along the magnetic field is suppressed. Electron spins directed transverse to the magnetic field relax completely in a time on the order of the precession period of its spin in the field of the frozen fluctuation of the nuclear spins. Comparison with experiment shows that the hyperfine interaction with nuclei may be the dominant mechanism of electron spin relaxation in quantum dots

In vitro potency, in vitro and in vivo efficacy of liposomal alendronate in combination with γδ T cell immunotherapy in mice

Nitrogen-containing bisphosphonate (N-BP), including zoledronic acid (ZOL) and alendronate (ALD), have been proposed as sensitisers in γδ T cell immunotherapy in pre-clinical and clinical studies. Therapeutic efficacy of N-BPs is hampered by their rapid renal excretion and high affinity for bone. Liposomal formulations of N-BP have been proposed to improve accumulation in solid tumours. Liposomal alendronate (L-ALD) has been suggested as a suitable alternative to liposomal ZOL (L-ZOL), due to unexpected mice death experienced in pre-clinical studies with the latter. Only one study so far has proven the therapeutic efficacy of L-ALD, in combination with γδ T cell immunotherapy, after intraperitoneal administration of γδ T cell resulting in delayed growth of ovarian cancer in mice. This study aims to assess the in vitro efficacy of L-ALD, in combination with γδ T cell immunotherapy, in a range of cancerous cell lines, using L-ZOL as a comparator. The therapeutic efficacy was tested in a pseudo-metastatic lung mouse model, following intravenous injection of γδ T cell, L-ALD or the combination. In vivo biocompatibility and organ biodistribution studies of L-BPs were undertaken simultaneously. Higher concentrations of L-ALD (40–60 μM) than L-ZOL (3–10 μM) were required to produce a comparative reduction in cell viability in vitro, when used in combination with γδ T cells. Significant inhibition of tumour growth was observed after treatment with both L-ALD and γδ T cells in pseudo-metastatic lung melanoma tumour-bearing mice after tail vein injection of both treatments, suggesting that therapeutically relevant concentrations of L-ALD and γδ T cell could be achieved in the tumour sites, resulting in significant delay in tumour growth

Joint data imputation and mechanistic modelling for simulating heart-brain interactions in incomplete datasets

The use of mechanistic models in clinical studies is limited by the lack of multi-modal patients data representing different anatomical and physiological processes. For example, neuroimaging datasets do not provide a sufficient representation of heart features for the modeling of cardiovascular factors in brain disorders. To tackle this problem we introduce a probabilistic framework for joint cardiac data imputation and personalisation of cardiovascular mechanistic models, with application to brain studies with incomplete heart data. Our approach is based on a variational framework for the joint inference of an imputation model of cardiac information from the available features, along with a Gaussian Process emulator that can faithfully reproduce personalised cardiovascular dynamics. Experimental results on UK Biobank show that our model allows accurate imputation of missing cardiac features in datasets containing minimal heart information, e.g. systolic and diastolic blood pressures only, while jointly estimating the emulated parameters of the lumped model. This allows a novel exploration of the heart-brain joint relationship through simulation of realistic cardiac dynamics corresponding to different conditions of brain anatomy

Polarization of coalitions in an agent-based model of political discourse

Political discourse is the verbal interaction between political actors in a policy domain. This article explains the formation of polarized advocacy or discourse coalitions in this complex phenomenon by presenting a dynamic, stochastic, and discrete agent-based model based on graph theory and local optimization. In a series of thought experiments, actors compute their utility of contributing a specific statement to the discourse by following ideological criteria, preferential attachment, agenda-setting strategies, governmental coherence, or other mechanisms. The evolving macro-level discourse is represented as a dynamic network and evaluated against arguments from the literature on the policy process. A simple combination of four theoretical mechanisms is already able to produce artificial policy debates with theoretically plausible properties. Any sufficiently realistic configuration must entail innovative and path-dependent elements as well as a blend of exogenous preferences and endogenous opinion formation mechanisms

Exploring assessment of medical students\u27 competencies in pain medicine - A review

Introduction: Considering the continuing high prevalence and public health burden of pain, it is critical that medical students are equipped with competencies in the field of pain medicine. Robust assessment of student expertise is integral for effective implementation of competency-based medical education. Objective: The aim of this review was to describe the literature regarding methods for assessing pain medicine competencies in medical students. Method: PubMed, Medline, EMBASE, ERIC, and Google Scholar, and BEME data bases were searched for empirical studies primarily focusing on assessment of any domain of pain medicine competencies in medical students published between January 1997 and December 2016. Results: A total of 41 studies met the inclusion criteria. Most assessments were performed for low-stakes summative purposes and did not reflect contemporary theories of assessment. Assessments were predominantly undertaken using written tests or clinical simulation methods. The most common pain medicine education topics assessed were pain pharmacology and the management of cancer and low-back pain. Most studies focussed on assessment of cognitive levels of learning as opposed to more challenging domains of demonstrating skills and attitudes or developing and implementing pain management plans. Conclusion: This review highlights the need for more robust assessment tools that effectively measure the abilities of medical students to integrate pain-related competencies into clinical practice. A Pain Medicine Assessment Framework has been developed to encourage systematic planning of pain medicine assessment at medical schools internationally and to promote continuous multidimensional assessments in a variety of clinical contexts based on well-defined pain medicine competencies