Trends in long-term prescribing of dependence forming medicines

Using patient-level primary care data to estimate the extent to which antidepressant medicines are prescribed to people continuously for long periods of time. Aim This descriptive research used patient-level primary care data to estimate the extent to which antidepressant medicines are prescribed to people continuously for long periods of time. The study also drew on survey data and data on the number of prescriptions dispensed. Findings - The number of antidepressant prescriptions dispensed each year in England doubled between 2008 and 2018 - Survey data show that the proportion of adults reporting use of antidepressants in the past year increased in the 1990s, and again between 2007 and 2014 - The average length of time that antidepressants are continuously prescribed to people for has increased over time. - Some types of antidepressants (for example, tricyclics and other antidepressants) tend to be prescribed for longer periods than other types (such as SSRIs). - In 2014, one in twelve prescribing periods for tricyclics and other antidepressants lasted for three years or more Methods The analyses in this report are descriptive and show the overall prevalence of long-term prescribing in each year. We used a sample of around 50,000 patients prescribed at least one antidepressant medicine between 2000 and 2017. This was drawn from the Clinical Practice Research Datalink (CPRD). The CPRD contains data about prescriptions issued by GPs (including the length and size of prescription) and characteristics of the patients prescribed to (such as their age, sex, and area where they live). Medicines were grouped for analysis into: tricyclics, selective serotonin reuptake inhibitors (SSRIs), and other ADMs. The length of individual prescriptions and continuous prescribing periods were derived using information on consultation dates, the quantity of tablets prescribed, and the numeric daily dose

Relative pay and job satisfaction: some new evidence

This paper investigates the determinants of job satisfaction using data from the National Educational Longitudinal Study. The determinants of interest include actual pay, relative pay, hours of work, job autonomy and several personal characteristics. We also investigate the determinants of satisfaction with pay conditional on a worker's satisfaction with other domains of job satisfaction, such as satisfaction with job security. We find that relative pay is statistically significant but that its effect on satisfaction with pay is relatively small. Job autonomy has a powerful influence on satisfaction with pay. So too does being black.

Isogeometric analysis for functionally graded microplates based on modified couple stress theory

Analysis of static bending, free vibration and buckling behaviours of functionally graded microplates is investigated in this study. The main idea is to use the isogeometric analysis in associated with novel four-variable refined plate theory and quasi-3D theory. More importantly, the modified couple stress theory with only one material length scale parameter is employed to effectively capture the size-dependent effects within the microplates. Meanwhile, the quasi-3D theory which is constructed from a novel seventh-order shear deformation refined plate theory with four unknowns is able to consider both shear deformations and thickness stretching effect without requiring shear correction factors. The NURBS-based isogeometric analysis is integrated to exactly describe the geometry and approximately calculate the unknown fields with higher-order derivative and continuity requirements. The convergence and verification show the validity and efficiency of this proposed computational approach in comparison with those existing in the literature. It is further applied to study the static bending, free vibration and buckling responses of rectangular and circular functionally graded microplates with various types of boundary conditions. A number of investigations are also conducted to illustrate the effects of the material length scale, material index, and length-to-thickness ratios on the responses of the microplates.Comment: 57 pages, 14 figures, 18 table

Optimal path-following control of a smart powered wheelchair.

This paper proposes an optimal path-following control approach for a smart powered wheelchair. Lyapunov's second method is employed to find a stable position tracking control rule. To guarantee robust performance of this wheelchair system even under model uncertainties, an advanced robust tracking is utilised based on the combination of a systematic decoupling technique and a neural network design. A calibration procedure is adopted for the wheelchair system to improve positioning accuracy. After the calibration, the accuracy is improved significantly. Two real-time experimental results obtained from square tracking and door passing tasks confirm the performance of proposed approach

Neuro-sliding mode multivariable control of a powered wheelchair.

This paper proposes a neuro-sliding mode multivariable control approach for the control of a powered wheelchair system. In the first stage, a systematic decoupling technique is applied to the wheelchair system in order to reduce the multivariable control problem into two independent scalar control problems. Then two Neuro-Sliding Mode Controllers (NSMCs) are designed for these independent subsystems to guarantee system robustness under model uncertainties and unknown external disturbances. Both off-line and on-line trainings are involved in the second stage. Real-time experimental results confirm that robust performance for this multivariable wheelchair control system under model uncertainties and unknown external disturbances can indeed be achieved

Robust multivariable strategy and its application to a powered wheelchair

The paper proposes a systematic robust multivariable control strategy based on combination of systematic triangularization technique and robust control strategies. Two design stages are required. In the first design stage, multivariable control problem is reduced into a series of scalar control problems via triangularization technique. For each specific scalar system, two advanced control strategies are proposed and implemented in the second design stage. The first one is based on Model Predictive Control, which is an iterative, finite horizon optimization procedure. The second control strategy is known as Neuro-Sliding Mode Control, which integrates Sliding Mode Control (SMC) and Neural Network Design to achieve both chattering-free and system robustness. Real-time implementation on a powered wheelchair system confirms that robustness and desired performance of a multivariable system under model uncertainties and unknown external disturbances can indeed be achieved by the combination of triangularization technique and Neuro-Sliding Mode Control. ©2009 IEEE

Complete Embedded Self-Translating Surfaces under Mean Curvature Flow

We describe a construction of complete embedded self-translating surfaces under mean curvature flow by desingularizing the intersection of a finite family of grim reapers in general position.Comment: 42 pages, 8 figures. v2: typos correcte