Determination of equivalent sound speed profiles for ray tracing in near-ground sound propagation.

The determination of appropriate sound speed profiles in the modeling of near-ground propagation using a ray tracing method is investigated using a ray tracing model which is capable of performing axisymmetric calculations of the sound field around an isolated source. Eigenrays are traced using an iterative procedure which integrates the trajectory equations for each ray launched from the source at a specific direction. The calculation of sound energy losses is made by introducing appropriate coefficients to the equations representing the effect of ground and atmospheric absorption and the interaction with the atmospheric turbulence.

Internal fixation of hip osteotomy in children. Successful healing in 26 children without postoperative casting.

We assessed the necessity of postoperative casting when a plate was used for fixation of a proximal femoral varus osteotomy. 26 children without postoperative immobilization were compared to 17 children with a cast. No complications were encountered in either group of children and all osteotomies showed similar healing.

Sagittal profiles of the spine.

The sagittal plane of the growing spine was studied from standardized radiographs of 670 normal subjects to establish standards of reference for thoracic kyphosis, lumbosacral lordosis, and sacral inclination. Cobb's method of measuring spinal deformities was compared with new indices of kyphosis and lordosis that take into consideration the length and width of each curve. Boys and girls had comparable degrees of kyphosis.

Surgical treatment of the symptomatic accessory navicular.

The accessory navicular is occasionally the source of pain and local tenderness over the instep. If conservative measures fail, surgical treatment may be required and the results of 62 operations to one or both feet in 47 patients are reported. Twenty-six patients were treated by the Kidner operation, in which the main insertion of the tibialis posterior is re-routed; in the remaining 21 the ossicle was merely excised.

Home traction in the management of congenital dislocation of the hip.

A retrospective review of sixty children with seventy-eight congenitally dislocated hips who had pre-reduction traction at home was undertaken to assess the effectiveness of the traction and the incidence of severe complications, with specific reference to the incidence and severity of avascular necrosis. Thirty other children with forty-two congenitally dislocated hips who had pre-reduction traction while in the hospital were used as controls. Traction failed to radiologically improve the position of the head in relation to the acetabulum in two hips in each group.

The infrequency of malignant disease in diaphyseal aclasis and neurofibromatosis.

The association of diaphyseal aclasis and neurofibromatosis with malignant neoplasms has been variously reported as between 5 and 28% of all cases, but malignant disease invariably presents at hospital and the true frequency from an unselected group is unknown. The current survey reviews not only hospital patients but also their affected relatives, with particular reference to malignant disease and the cause of death in all family members. A survey of 36 index patients and 80 known affected relatives with diaphyseal aclasis and 37 index patients and 33 known affected relatives with neurofibromatosis has been carried out.