Ford Motor Company

About: Ford Motor Company is a company organization based out in Dearborn, Michigan, United States. It is known for research contribution in the topics: Internal combustion engine & Clutch. The organization has 36123 authors who have published 51450 publications receiving 855200 citations. The organization is also known as: Ford Motor & Ford Motor Corporation.

Sex differences in depression: a role for preexisting anxiety

Abstract: The role of anxiety disorders in the development of sex differences in major depression is analyzed. Data come from a longitudinal epidemiologic study of young adults in the Detroit, Michigan area. The Diagnostic Interview Schedule, revised according to DSM-III-R, was used at baseline to measure lifetime psychiatric disorders and at follow-up to measure psychiatric disorders during the 3.5-year interval since baseline assessment. Consistent with previous reports, the lifetime prevalence of major depression was nearly two-fold higher in females than in males. The sex difference was primarily in major depression comorbid with anxiety disorders. Results from Cox-proportional hazards models, with time-dependent covariates, showed that prior anxiety disorder increased the risk for subsequent major depression in both sexes, with no evidence of an interaction. History of anxiety disorder, including number of prior anxiety disorders, accounted for a considerable part of the observed sex difference in major depression. Controlling for prior anxiety reduced by more than 50% the coefficient that estimates the association between gender and major depression. The results suggest that the higher occurrence of anxiety disorders in females than males beginning early in life might explain in large part the higher female risk for major depression. They emphasize the need for further research on sex differences in anxiety disorders.

Observer design for nonlinear systems with discrete-time measurements

Abstract: This paper focuses on the development of asymptotic observers for nonlinear discrete-time systems. It is argued that instead of trying to imitate the linear observer theory, the problem of constructing a nonlinear observer can be more fruitfully studied in the context of solving simultaneous nonlinear equations. In particular, it is shown that the discrete Newton method, properly interpreted, yields an asymptotic observer for a large class of discrete-time systems, while the continuous Newton method may be employed to obtain a global observer. Furthermore, it is analyzed how the use of Broyden's method in the observer structure affects the observer's performance and its computational complexity. An example illustrates some aspects of the proposed methods; moreover, it serves to show that these methods apply equally well to discrete-time systems and to continuous-time systems with sampled outputs. >

Mechanical stability and adhesion of microstructures under capillary forces. II. Experiments

Abstract: For pt.I see ibid., vol.2, p. 33 (1993). Strong capillary forces are developed in the fabrication process of surface micromachined structures during the wet etch of sacrificial layers. The magnitude of these forces is in some cases sufficient to deform and pin these structures to the substrate resulting in device failure. The deflection, mechanical stability, and adhesion of thin micromechanical structure under capillary forces are examined. Microstructure adhesion is considered and experimental data for polycrystalline silicon microstructures are presented. >

Posttraumatic stress disorder and drug disorders: testing causal pathways.

Abstract: Background Although there is a high degree of comorbidity between posttraumatic stress disorder (PTSD) and drug use disorders, little is known about causal relationships between PTSD, exposure to traumatic events, and drug use disorders. Methods In a longitudinal study in southeast Michigan, 1007 adults aged 21 to 30 years were initially assessed in 1989 and were followed up 3 and 5 years later, in 1992 and 1994. Psychiatric disorders according to DSM-III-R criteria were measured by the National Institute of Mental Health Diagnostic Interview Schedule. To take into account temporal sequencing, the associations between PTSD, traumatic events, and drug use disorders were analyzed by using Cox proportional hazards models with time-dependent covariates. Results Posttraumatic stress disorder signaled an increased risk of drug abuse or dependence (hazards ratio, 4.5; 95% confidence interval, 2.6-7.6, adjusted for sex), whereas exposure to traumatic events in the absence of PTSD did not increase the risk of drug abuse or dependence. The risk for abuse or dependence was the highest for prescribed psychoactive drugs (hazards ratio, 13.0; 95% confidence interval, 5.3-32.0). There was no evidence that preexisting drug abuse or dependence increased the risk of subsequent exposure to traumatic events or the risk of PTSD after traumatic exposure. Conclusion The results suggest that drug abuse or dependence in persons with PTSD might be the inadvertent result of efforts to medicate symptoms, although the possibility of shared vulnerability to PTSD and drug use disorders cannot be ruled out.