A methodology is presented on assessing the effectiveness of flexible joints in mitigating the consequences of faulting on buried steel pipelines through a comprehensive analysis that incorporates the uncertainty of fault displacement magnitude and the response of the pipeline itself. The proposed methodology is a two-step process. In the first step the probabilistic nature of the fault displacement magnitude is evaluated by applying the Probabilistic Fault Displacement Hazard Analysis, considering also all pertinent uncertainties. The second step is the “transition” from seismological data to the pipeline structural response through the fault displacement components as the adopted vector intensity measure. To mitigate the consequences of faulting on pipelines, flexible joints between pipeline parts are proposed as innovative measure for reducing the deformation of pipeline walls. Thus, the mechanical behavior of continuous pipelines and pipelines with flexible joints is numerically assessed and strains are extracted in order to develop the corresponding strain hazard curves. The latter are a useful engineering tool for pipeline – fault crossing risk assessment and for the effectiveness evaluation of flexible joints as innovative mitigating measures against the consequences of faulting on pipelines.
Daily glucocorticoid therapy of children with congenital adrenal hyperplasia (CAH) frequently results in a suboptimal mature height. In contrast, pharmacological doses of prednisone given on alternate days generally allow normal growth in children with autoimmune, hematological, and renal disorders. Moreover, alternate day prednisone therapy suppresses adrenal androgen secretion on both the day on and the day off therapy in patients with systemic lupus erythematosus. We hypothesized that alternate day prednisone therapy might be efficacious in the treatment of CAH. To evaluate this hypothesis, we studied an 11-yr-old girl with salt-losing 21-hydroxylase deficiency and severe asthma treated with alternate day prednisone therapy (20 mg every other day) for over 3 yr. During this period her linear growth was along the 65th percentile, and her bone age paralleled her chronological age. Pubertal development was normal, and she had no signs of androgen or glucocorticoid excess. In keeping with her clinical picture, basal (24-h samples drawn every 60 min) and ovine CRH-stimulated plasma adrenal androgen (dehydroepiandrosterone sulfate and δ4-androstenedione) concentrations and 24-h urinary 17-ketosteroid excretion were low on both the day on and the day off prednisone. However, her plasma ACTH and 17-hydroxyprogesterone levels were markedly elevated on both days. The adrenal androgen suppression, therefore, appeared independent of the level of ACTH, suggesting different regulation of the zona fasciculata and the zona reticularis. GH secretion, assessed by measurement of plasma GH every 20 min for 48 h, was normal on both the on and off days of prednisone therapy. Therefore, in this girl pharmacological doses of prednisone given on alternate days caused sustained adrenal androgen suppression and allowed normal growth and pubertal development, despite persistently elevated plasma ACTH and 17-hydroxyprogesterone levels.
Summary Yield frequency spectra (YFS) are introduced to enable the direct design of a structure subject to a set of seismic performance objectives. YFS offer a unique view of the entire solution space for structural performance. This is portrayed in terms of the mean annual frequency (MAF) of exceeding arbitrary ductility (or displacement) thresholds, versus the base shear strength of a structural system having specified yield displacement and capacity curve shape. YFS can be computed nearly instantaneously using publicly available software or closed‐form solutions, for any system whose response can be satisfactorily approximated by an equivalent nonlinear single‐degree‐of‐freedom oscillator. Because the yield displacement typically is a more stable parameter for performance‐based seismic design compared with the period, the YFS format is especially useful for design. Performance objectives stated in terms of the MAF of exceeding specified ductility (or displacement) thresholds are used to determine the lateral strength that governs the design of the structure. Both aleatory and epistemic uncertainties are considered, the latter at user‐selected confidence levels that can inject the desired conservatism in protecting against different failure modes. Near‐optimal values of design parameters can be determined in many cases in a single step. Copyright © 2016 John Wiley & Sons, Ltd.