Applying a Dynamical Systems Model and Network Theory to Major Depressive Disorder

Mental disorders like major depressive disorder can be seen as complex dynamical systems. In this study we investigate the dynamic behaviour of individuals to see whether or not we can expect a transition to another mood state. We introduce a mean field model to a binomial process, where we reduce a dynamic multidimensional system (stochastic cellular automaton) to a one-dimensional system to analyse the dynamics. Using maximum likelihood estimation, we can estimate the parameter of interest which, in combination with a bifurcation diagram, reflects the expectancy that someone has to transition to another mood state. After validating the proposed method with simulated data, we apply this method to two empirical examples, where we show its use in a clinical sample consisting of patients diagnosed with major depressive disorder, and a general population sample. Results showed that the majority of the clinical sample was categorized as having an expectancy for a transition, while the majority of the general population sample did not have this expectancy. We conclude that the mean field model has great potential in assessing the expectancy for a transition between mood states. With some extensions it could, in the future, aid clinical therapists in the treatment of depressed patients.Comment: arXiv admin note: text overlap with arXiv:1610.0504

Elliptical orbits in the Bloch sphere

As is well known, when an SU(2) operation acts on a two-level system, its Bloch vector rotates without change of magnitude. Considering a system composed of two two-level systems, it is proven that for a class of nonlocal interactions of the two subsystems including \sigma_i\otimes\sigma_j (with i,j \in {x,y,z}) and the Heisenberg interaction, the geometric description of the motion is particularly simple: each of the two Bloch vectors follows an elliptical orbit within the Bloch sphere. The utility of this result is demonstrated in two applications, the first of which bears on quantum control via quantum interfaces. By employing nonunitary control operations, we extend the idea of controllability to a set of points which are not necessarily connected by unitary transformations. The second application shows how the orbit of the coherence vector can be used to assess the entangling power of Heisenberg exchange interaction.Comment: 9 pages, 4 figures, few corrections, J. Opt. B: Quantum Semiclass. Opt. 7 (2005) S1-S

Unbounded-Error Classical and Quantum Communication Complexity

Since the seminal work of Paturi and Simon \cite[FOCS'84 & JCSS'86]{PS86}, the unbounded-error classical communication complexity of a Boolean function has been studied based on the arrangement of points and hyperplanes. Recently, \cite[ICALP'07]{INRY07} found that the unbounded-error {\em quantum} communication complexity in the {\em one-way communication} model can also be investigated using the arrangement, and showed that it is exactly (without a difference of even one qubit) half of the classical one-way communication complexity. In this paper, we extend the arrangement argument to the {\em two-way} and {\em simultaneous message passing} (SMP) models. As a result, we show similarly tight bounds of the unbounded-error two-way/one-way/SMP quantum/classical communication complexities for {\em any} partial/total Boolean function, implying that all of them are equivalent up to a multiplicative constant of four. Moreover, the arrangement argument is also used to show that the gap between {\em weakly} unbounded-error quantum and classical communication complexities is at most a factor of three.Comment: 11 pages. To appear at Proc. ISAAC 200

Global and local relaxation of a spin-chain under exact Schroedinger and master-equation dynamics

We solve the Schroedinger equation for an interacting spin-chain locally coupled to a quantum environment with a specific degeneracy structure. The reduced dynamics of the whole spin-chain as well as of single spins is analyzed. We show, that the total spin-chain relaxes to a thermal equilibrium state independently of the internal interaction strength. In contrast, the asymptotic states of each individual spin are thermal for weak but non-thermal for stronger spin-spin coupling. The transition between both scenarios is found for couplings of the order of $0.1 \times \Delta E$, with $\Delta E$ denoting the Zeeman-splitting. We compare these results with a master equation treatment; when time averaged, both approaches lead to the same asymptotic state and finally with analytical results.Comment: RevTeX, 8 pages, 14 figures, added DOI and forgotten reference

Exploring the interrelatedness of risk factors for child maltreatment: A network approach

Background: Theories on the etiology of child maltreatment generally focus on the interaction between multiple risk and protective factors. Moreover, the quadratic model of cumulative risk describes a threshold at which the risk of child maltreatment increases exponentially, suggesting a synergistic effect between risk factors. Objective: This study explored the interrelatedness of risk factors for child maltreatment. Participants and Setting: The sample consisted of risk assessments performed for both high-risk families (n = 2,399; child protection services) and lower risk families (n = 1,904; community outreach services). Methods : Network analyses were performed on parental risk factors. Three networks were constructed: a cross-sample network, a high-risk network, and a lower risk network. The relations between risk factors were examined, as well as the centrality of each risk factor in these networks. Additionally, the networks of the two samples were compared. Results : The networks revealed that risk factors for child maltreatment were highly interrelated, which is consistent with Belsky’s multi-dimensional perspective on child maltreatment. As expected, risk factors were generally stronger related to each other in the high-risk sample than in the lower risk sample. Centrality analyses showed that the following risk factors play an important role in the development of child maltreatment: “Caregiver was maltreated as a child”, “History of domestic violence”, and “Caregiver is emotionally absent”. Conclusions : We conclude that studying the interrelatedness of risk factors contributes to knowledge on the etiology of child maltreatment and the improvement of both risk assessment procedures and interventions for child maltreatment

Электропривод насоса перекачки золошлаковой пульпы

Объектом исследования является система автоматического управления насоса перекачки золошлаковой пульпы. Цель работы – разработка и исследование электропривода насоса перекачки золошлаковой пульпы. В выпускной квалификационной работе произведён расчет и выбор приводного двигателя преобразователя частоты для управления электроприводами. Обоснован выбор способа управления, рассчитаны механические и электромеханические характеристики.The object of study is an automatic control system for the pump for transferring ash and slag pulp. The purpose of the work is the development and study of the electric drive of the pump for transferring ash and slag pulp. In the final qualification work, the calculation and selection of the drive motor of the frequency converter for controlling electric drives were made. The choice of control method is justified, mechanical and electromechanical characteristics are calculated

Metastability in the BCS model

We discuss metastable states in the mean-field version of the strong coupling BCS-model and study the evolution of a superconducting equilibrium state subjected to a dynamical semi-group with Lindblad generator in detailed balance w.r.t. another equilibrium state. The intermediate states are explicitly constructed and their stability properties are derived. The notion of metastability in this genuine quantum system, is expressed by means of energy-entropy balance inequalities and canonical coordinates of observables

Quantum response of dephasing open systems

We develop a theory of adiabatic response for open systems governed by Lindblad evolutions. The theory determines the dependence of the response coefficients on the dephasing rates and allows for residual dissipation even when the ground state is protected by a spectral gap. We give quantum response a geometric interpretation in terms of Hilbert space projections: For a two level system and, more generally, for systems with suitable functional form of the dephasing, the dissipative and non-dissipative parts of the response are linked to a metric and to a symplectic form. The metric is the Fubini-Study metric and the symplectic form is the adiabatic curvature. When the metric and symplectic structures are compatible the non-dissipative part of the inverse matrix of response coefficients turns out to be immune to dephasing. We give three examples of physical systems whose quantum states induce compatible metric and symplectic structures on control space: The qubit, coherent states and a model of the integer quantum Hall effect.Comment: Article rewritten, two appendices added. 16 pages, 2 figure

Radiokomunikacja ruchoma. Przegląd Zagadnień Łączności, 1966, nr 1 (52)

Opracowania na podstawie artykułó