255 research outputs found

    Talk-based approaches to support people who are distressed by their experience of hearing voices: a scoping review

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    Background: The positive effects of both antipsychotic medication and cognitive behavioral therapy in psychosis (CBTp) for people who are distressed by their experience of hearing voices remain limited. As a result, there has been a recent surge in talk-based individual approaches. Many of these continue not to be very well known nor implemented in practice. Some of the approaches may focus more on understanding and dealing constructively with voices, an element that has been identified as potentially helpful by voice hearers. Existing barriers to a wider implementation include both the widespread pathologization of hearing voices and a lack of mental health professionals who have been trained and trusted to carry out these new interventions. Methods: This scoping review aimed to identify and describe a current synthesis of talk-based individual approaches for people who hear voices, including studies independently of method of study or approach, diagnosis of voice hearers nor of the professional background of interventionists. Results: Nine different talk-based approaches were identified. These included: (1) Cognitive Behavioral Therapy for Psychosis (CBTp); (2) AVATAR therapy; (3) Making Sense of Voices (MsV) aka Experience Focused Counselling (EFC); (4) Relating Therapy; (5) Acceptance and Commitment Therapy; (6) Smartphone-based Coping-focused Intervention; (7) Prolonged and Virtual Reality Exposure Therapy; (8) Eye Movement Desensitization and Reprocessing, and (9) Individual Mindfulness-based Program for Voice Hearing. The different approaches differed greatly in relation to the number of sessions, length of time offered and the scientific evidence on efficacy. Psychologists represented the main professional group of interventionists. CBTp and the MsV/EFC approach also included health professionals, like nurses, as implementers. Most of the approaches showed positive outcomes in relation to voice related distress levels. None identified overall or voice specific deteriorations. Conclusion: There appears to be a strong case for the implementation of a broader heterogeneity of approaches in practice. This would also be in line with recommendations for recovery focused services and requirements of voice hearers. A greater emphasis on whole systems implementation and thus the involvement of frontline staff, like nurses, in the delivery of these approaches would likely reduce the research-practice implementation gap

    Development and Application of a Versatile Balloon-Borne DOAS Spectrometer for Skylight Radiance and Atmospheric Trace Gas Profile Measurements

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    In the framework of this thesis, a novel balloon-borne DOAS instrument was developed, characterized in the laboratory and employed during 5 stratospheric balloon flights. Its light weight and small size allows versatile applications on different platforms and under several observation geometries (scanning and fixed limb, nadir, and direct sunlight). Skylight radiances in the UV/visible range between 330 and 550 nm are measured, and the recorded spectra are analyzed for column densities of ozone, NO2, BrO, H2O, and O4 along the line of sight by applying the Differential Optical Absorption Spectroscopy (DOAS) method. Radiative Transfer (RT) calculations are used to (a) simulate the measured quantities and (b) infer vertical profiles of O3, NO2, and BrO concentrations. Since the measurements were performed under a variety of viewing geometries, they provide a stringent validation of the applied Monte Carlo RT model. The new method of atmospheric trace gas profiling by balloon-borne UV/vis limb scatter measurements is tested against simultaneous measurements of the same parameters available from in-situ, or UV/vis/near IR solar occultation observations performed on the same payload. Reasonable agreement is found between (a) measured and RT calculated limb radiances and (b) inferred limb O3, NO2, and BrO and correlative profile measurements when properly accounting for all relevant atmospheric parameters (temperature, pressure, aerosol extinction, and major absorbing trace gases). Additionally, scanning limb observations provide time-resolved profile information of radicals during sunset

    A holistic integrated dynamic design and modelling approach applied to the development of ultraprecision micro-milling machines

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    Ultraprecision machines with small footprints or micro-machines are highly desirable for micro-manufacturing high-precision micro-mechanical components. However, the development of the machines is still at the nascent stage by working on an individual machine basis and hence lacks generic scientific approach and design guidelines. Using computer models to predict the dynamic performance of ultraprecision machine tools can help manufacturers substantially reduce the lead time and cost of developing new machines. Furthermore, the machine dynamic performance depends not only upon the mechanical structure and components but also the control system and electronic drives. This paper proposed a holistic integrated dynamic design and modelling approach, which supports analysis and optimization of the overall machine dynamic performance at the early design stage. Based on the proposed approach the modelling and simulation process on a novel 5-axis bench-top ultraprecision micro-milling machine tool – UltraMill – is presented. The modelling and simulation cover the dynamics of the machine structure, moving components, control system and the machining process, and are used to predict the overall machine performance of two typical configurations. Preliminary machining trials have been carried out and provided the evidence of the approach being helpful to assure the machine performing right at the first setup

    Robust Control Performance for Open Quantum Systems

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    The robustness of quantum control in the presence of uncertainties is important for practical applications but their quantum nature poses many challenges for traditional robust control. In addition to uncertainties in the system and control Hamiltonians and initial state preparation, there is uncertainty about interactions with the environment leading to decoherence. This paper investigates the robust performance of control schemes for open quantum systems subject to such uncertainties. A general formalism is developed, where performance is measured based on the transmission of a dynamic perturbation or initial state preparation error to a final density operator error. This formulation makes it possible to apply tools from classical robust control, especially structured singular value analysis, to assess robust performance of controlled, open quantum systems. However, there are additional difficulties that must be overcome, especially at low frequency (s0s\approx0). For example, at s=0s=0, the Bloch equations for the density operator are singular, and this causes lack of continuity of the structured singular value. We address this issue by analyzing the dynamics on invariant subspaces and defining a pseudo-inverse that enables us to formulate a specialized version of the matrix inversion lemma. The concepts are demonstrated with an example of two qubits in a leaky cavity under laser driving fields and spontaneous emission. In addition, a new performance index is introduced for this system. Instead of the tracking or transfer fidelity error, performance is measured by the steady-steady entanglement generated, which is quantified by a non-linear function of the system state called concurrence. Simulations show that there is no conflict between this performance index, its log-sensitivity and stability margin under decoherence, unlike for conventional control problems [...].Comment: 12 pages, 5 figures, 2 table

    Sample-efficient Model-based Reinforcement Learning for Quantum Control

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    We propose a model-based reinforcement learning (RL) approach for noisy time-dependent gate optimization with improved sample complexity over model-free RL. Sample complexity is the number of controller interactions with the physical system. Leveraging an inductive bias, inspired by recent advances in neural ordinary differential equations (ODEs), we use an auto-differentiable ODE parametrised by a learnable Hamiltonian ansatz to represent the model approximating the environment whose time-dependent part, including the control, is fully known. Control alongside Hamiltonian learning of continuous time-independent parameters is addressed through interactions with the system. We demonstrate an order of magnitude advantage in the sample complexity of our method over standard model-free RL in preparing some standard unitary gates with closed and open system dynamics, in realistic numerical experiments incorporating single shot measurements, arbitrary Hilbert space truncations and uncertainty in Hamiltonian parameters. Also, the learned Hamiltonian can be leveraged by existing control methods like GRAPE for further gradient-based optimization with the controllers found by RL as initializations. Our algorithm that we apply on nitrogen vacancy (NV) centers and transmons in this paper is well suited for controlling partially characterised one and two qubit systems.Comment: 14+6 pages, 6+4 figures, comments welcome

    Systemic epothilone D improves hindlimb function after spinal cord contusion injury in rats

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    Following a spinal cord injury (SCI) a growth aversive environment forms, consisting of a fibroglial scar and inhibitory factors, further restricting the already low intrinsic growth potential of injured adult central nervous system (CNS) neurons. Previous studies have shown that local administration of the microtubule-stabilizing drug paclitaxel or epothilone B (Epo B) reduce fibrotic scar formation and axonal dieback as well as induce axonal growth/sprouting after SCI. Likewise, systemic administration of Epo B promoted functional recovery. In this study, we investigated the effects of epothilone D (Epo D), an analog of Epo B with a possible greater therapeutic index, on fibrotic scarring, axonal sprouting and functional recovery after SCI. Delayed systemic administration of Epo D after a moderate contusion injury (150 kDyn) in female Fischer 344 rats resulted in a reduced number of footfalls when crossing a horizontal ladder at 4 and 8 weeks post-injury. Hindlimb motor function assessed with the BBB open field locomotor rating scale and Catwalk gait analysis were not significantly altered. Moreover, formation of laminin positive fibrotic scar tissue and 5-HT positive serotonergic fiber length caudal to the lesion site were not altered after treatment with Epo D. These findings recapitulate a functional benefit after systemic administration of a microtubule-stabilizing drug in rat contusion SCI

    Design of a five-axis ultra-precision micro-milling machine—UltraMill. Part 2: Integrated dynamic modelling, design optimisation and analysis

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    Using computer models to predict the dynamic performance of ultra-precision machine tools can help manufacturers to substantially reduce the lead time and cost of developing new machines. However, the use of electronic drives on such machines is becoming widespread, the machine dynamic performance depending not only on the mechanical structure and components but also on the control system and electronic drives. Bench-top ultra-precision machine tools are highly desirable for the micro-manufacturing of high-accuracy micro-mechanical components. However, the development is still at the nascent stage and hence lacks standardised guidelines. Part 2 of this two-part paper proposes an integrated approach, which permits analysis and optimisation of the entire machine dynamic performance at the early design stage. Based on the proposed approach, the modelling and simulation process of a novel five-axis bench-top ultra-precision micro-milling machine tool—UltraMill—is presented. The modelling and simulation cover the dynamics of the machine structure, the moving components, the control system and the machining process and are used to predict the entire machine performance of two typical configurations

    Magnetic nanoparticle-gel materials for development of joint phantoms for MPI and MRI

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    To evaluate the performance of commercial as well as custom-made scanners, dedicated phantoms with defined magnetic nanoparticle (MNP) distributions are required. Prerequisite for the development of such phantoms is the establishment of suitable MNP-matrix combinations. In this study, two different gel types were investigated as potential matrix materials: water-based biopolymers and synthetic polymers. These materials exhibit similar imaging behaviour to body tissue in MRI and MPI. Aqueous suspensions of MNP coated with different types of functionalized dextranes were used for embedding particles into the biopolymers, and organic fluids with oleic acid coated MNP for synthetic polymers, respectively. The obtained MNP-matrix combinations were tested for their shape stability. The homogeneity of MNP distribution and immobilization within the matrix was determined by optical investigation of the samples with a microscope, and the magnetic properties of the composite materials measured by vibrating sample magnetometry. From the tested combinations of MNP and matrix material, oleic acid coated MNP embedded in Permagel was found to be the most suitable for the construction of MPI phantoms. This was based on the reliable and homogeneous fixation of the MNP within the matrix without agglomeration of the particles

    Design and validation of a German version of the GSRS-IBS - an analysis of its psychometric quality and factorial structure

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    Background: Currently, a suitable questionnaire in German language is not available to monitor the progression and evaluate the severity of irritable bowel syndrome (IBS). Therefore, this study aimed to translate the Gastrointestinal Symptom Rating Scale for Irritable Bowel Syndrome (GSRS-IBS) into German and to evaluate its psychometric qualities and factorial structure. Methods: This study is based on a total sample of 372 participants [62.6% female, mean age = 41 years (SD = 17 years)]. 17.5% of the participants had a diagnosis of IBS, 19.9% were receiving treatment for chronic inflammatory bowel disease, 12.1% of the participants were recruited from a psychosomatic clinic, and 50.5% belonged to a control group. All participants completed the German version of GSRS-IBS (called Reizdarm-Fragebogen, RDF), as well as the Gießen Subjective Complaints List (GBB-24) and the Hospital Anxiety and Depression Scale - German version (HADS-D). Results: The internal consistency of the RDF total scale was at least satisfactory in all subsamples (Cronbach’s Alpha between .77 and .92), and for all subscales (Cronbach’s Alpha between .79 and .91). The item difficulties (between .25 and .73) and the item-total correlations (between .48 and .83) were equally satisfactory. Principal axis analysis revealed a four-factorial structure of the RDF items, which mainly resembled the structure of the English original. Convergent validity was established based on substantial and significant correlations with the stomach-complaint scale of the GBB-24 (r = .71; p < .01) and the anxiety (r = .42; p < .01) and depression scales (r = .43; p < .01) of the HADS-D. Conclusion: The German version of the GSRS-IBS RDF proves to be an effective, reliable, and valid questionnaire for the assessment of symptom severity in IBS, which can be used in clinical practice as well as in clinical studies
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