Patients' understanding of heart disease: relationships with decisions to seek help with acute symptoms, and with adherence to treatment.

Pre-hospital delay in seeking help for acute chest pain in patients with coronary heart disease is a major impediment to prompt thrombolysis. Failure to adhere to medication, attend cardiac rehabilitation where appropriate, and change lifestyle, all impair secondary prevention. This thesis examined psychological factors related to these problems, and the psychological models of illness held by patients diagnosed with acute coronary syndromes (ACS). Two main issues were investigated firstly, what factors were associated with shorter pre-hospital delays following symptom onset and secondly, whether cognitive models of illness predicted adherence to advice, psychological and emotional adjustment, and quality of life at 3 months and 13 months post-discharge. Data were collected from 269 patients diagnosed with ACS within five days of hospital admission. Analyses were focussed on the total time between symptom onset and admission to hospital (pre-hospital delay). This interval was divided into two phases time between symptom onset and decision to call for medical help (patient decision time), and time from call for help to admission (home to hospital delay). Patients were followed up 3 and 13 months later. Adherence to medical advice (lifestyle changes, adherence to medication, attendance at cardiac rehabilitation programmes), psychological distress and quality of life were measured by telephone interview and questionnaire. A number of sociodemographic, social, clinical and psychological factors were associated with pre-hospital delay. Beliefs about the causes of heart disease made an important contribution. Cognitive representations of heart disease measured during hospital admission did not predict adherence to treatment regimens after discharge, but significantly predicted later psychological and emotional adjustment, and quality of life. Theses findings have implications for understanding the contribution of psychological factors to the experience of acute heart disease, and point to methods of more effective patient care and management

Mesoscopic mean-field theory for spin-boson chains in quantum optical systems

We present a theoretical description of a system of many spins strongly coupled to a bosonic chain. We rely on the use of a spin-wave theory describing the Gaussian fluctuations around the mean-field solution, and focus on spin-boson chains arising as a generalization of the Dicke Hamiltonian. Our model is motivated by experimental setups such as trapped ions, or atoms/qubits coupled to cavity arrays. This situation corresponds to the cooperative (E⊗β) Jahn-Teller distortion studied in solid-state physics. However, the ability to tune the parameters of the model in quantum optical setups opens up a variety of novel intriguing situations. The main focus of this paper is to review the spin-wave theoretical description of this problem as well as to test the validity of mean-field theory. Our main result is that deviations from mean-field effects are determined by the interplay between magnetic order and mesoscopic cooperativity effects, being the latter strongly size-dependent

Photon-mediated qubit interactions in one-dimensional discrete and continuous models

In this work we study numerically and analytically the interaction of two qubits in a one-dimensionalwaveguide, as mediated by the photons that propagate through the guide. We develop strategies to assert the Markovianity of the problem, the effective qubit-qubit interactions, and their individual and collective spontaneous emission. We prove the existence of collective Lamb shifts that affect the qubit-qubit interactions and the dependency of coherent and incoherent interactions on the qubit separation. We also develop the scattering theory associated with these models and prove single-photon spectroscopy does probe the renormalized resonances of the singleand multiqubit models, in sharp contrast to earlier toy models in which individual and collective Lamb shifts cancel

Rabi lattice models with discrete gauge symmetry: Phase diagram and implementation in trapped-ion quantum simulators

We study a spin-boson chain that exhibits a local Z2 symmetry. We investigate the quantum phase diagram of the model by means of perturbation theory, mean-field theory, and the density matrix renormalization group method. Our calculations show the existence of a first-order phase transition in the region where the boson quantum dynamics is slow compared to the spin-spin interactions. Our model can be implemented with trapped-ion quantum simulators, leading to a realization of minimal models showing local gauge invariance and first-order phase transitions

Microwave energy supplied by a prototype oven prevents the spread of Fusarium wilt during the propagation of melon plantlets by seed

The re-use of propagation trays in nursery greenhouses is one of the main ways in which fusarium wilt is spread in melon crops (Cucumis melo). The causal agent of the disease is the fungus Fusarium oxysporum f. sp. melonis. This paper reports that exposing these seed trays to the energy produced by a prototype microwave oven during the commercial production of melon plantlets can prevent the spread of this pathogen with only a very small increase in production costs

Generalized Forward-Backward Splitting with Penalization for Monotone Inclusion Problems

We introduce a generalized forward-backward splitting method with penalty term for solving monotone inclusion problems involving the sum of a finite number of maximally monotone operators and the normal cone to the nonempty set of zeros of another maximal monotone operator. We show weak ergodic convergence of the generated sequence of iterates to a solution of the considered monotone inclusion problem, provided the condition corresponded to the Fitzpatrick function of the operator describing the set of the normal cone is fulfilled. Under strong monotonicity of an operator, we show strong convergence of the iterates. Furthermore, we utilize the proposed method for minimizing a large-scale hierarchical minimization problem concerning the sum of differentiable and nondifferentiable convex functions subject to the set of minima of another differentiable convex function. We illustrate the functionality of the method through numerical experiments addressing constrained elastic net and generalized Heron location problems

Positrons from Primordial Black Hole Microquasars and Gamma-ray Bursts

We propose several novel scenarios how capture of small sublunar-mass primordial black holes (PBHs) by compact stars, white dwarfs or neutron stars, can lead to distinct short gamma-ray bursts (sGRBs) as well as microquasars (MQs). In addition to providing new signatures, relativistic jets from these systems will accelerate positrons to high energies. We find that if PBHs constitute a sizable fraction of DM, they can significantly contribute to the excess observed in the positron flux by the Pamela, the AMS-02 and the Fermi-LAT experiments. Our proposal combines the beneficial features of astrophysical sources and dark matter.Comment: 9 pages, 2 figures, v2: significant revisions, published version, Physics Letters B (2018

Systems Quality and the Organizational Culture

The goal of this research is the identification of the aspects characterizing the Organizational Culture (OC) in a Venezuelan company operating in the business of Information Systems consultancy, maintenance and development services, and the impact of the OC in the development process of Information Systems. Based on the hypothesis that there are relationships existing between the OC and the development process of systems, the present study collected up-to-date information on this relationship, taking advantage of contributions by other authors, and using known methods, techniques and tools as well as others that were generated within the framework of the research, in order to carry out a field study in the organization that was selected