NACA Technical Notes

"The stresses in the two spars of a model of a wing having three rectangular cutouts were calculated by the PIBAL method, a modification of Southwell's method of systematic relaxations. The model was built and tested in the Polytechnic Institute of Brooklyn Aeronautical Laboratories and the deflections and strains measured were compared with calculated values. The agreement was found to be satisfactory" (p. 1)

An updated definition of stroke for the 21st century: a statement for healthcare professionals from the American Heart Association/American Stroke Association.

Despite the global impact and advances in understanding the pathophysiology of cerebrovascular diseases, the term stroke is not consistently defined in clinical practice, in clinical research, or in assessments of the public health. The classic definition is mainly clinical and does not account for advances in science and technology. The Stroke Council of the American Heart Association/American Stroke Association convened a writing group to develop an expert consensus document for an updated definition of stroke for the 21st century. Central nervous system infarction is defined as brain, spinal cord, or retinal cell death attributable to ischemia, based on neuropathological, neuroimaging, and/or clinical evidence of permanent injury. Central nervous system infarction occurs over a clinical spectrum: Ischemic stroke specifically refers to central nervous system infarction accompanied by overt symptoms, while silent infarction by definition causes no known symptoms. Stroke also broadly includes intracerebral hemorrhage and subarachnoid hemorrhage. The updated definition of stroke incorporates clinical and tissue criteria and can be incorporated into practice, research, and assessments of the public health