Measurement of water in rhyolitic glasses; calibration of an infrared spectroscopic technique

A series of natural rhyolitic obsidians were analyzed for their total water contents by a vacuum extraction technique. The grain size of the crushed samples can significantly affect these analyses. Coarse powders must be used in order to avoid surface-correlated water. These analyses were used to calibrate infrared spectroscopic measurements of water in glass using several infrared and near-infrared absorption bands. We demonstrate that infrared spectroscopy can yield precise determinations of not only total dissolved water contents, but also the concentrations of individual H-bearing species in natural and synthetic rhyolitic glasses on spots as small as a few tens of micrometers in diameter

Hammock Head Bandage

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Surgical Fixation of Bilateral Simultaneous Avulsion Fractures of the Proximal Tibia in a 12-Year-Old with History of Conservatively Managed Unilateral Tibial Avulsion Fracture

Fractures of the proximal tibial epiphysis are rare, representing less than 3% of all epiphyseal and 1% of all physeal injuries in adolescents. Bilateral injuries are extremely rare. The specific anatomical and histological features of the proximal tibial epiphysis make it vulnerable to a specific fracture pattern that occurs when the tensile force of the quadriceps is greater than the fibrocartilaginous tissue underlying the tibial tuberosity. We report the first case to our knowledge of a 12-year-old boy who sustained simultaneous bilateral tibial avulsion fractures on the background of a previous conservatively managed unilateral tibial tuberosity avulsion fracture. We report this case for its uniqueness and as an educational review of the anatomy, the mechanism of injury, and the development of classifying these fractures and discussion of the stages of the growing physis that determine the treatment approach

Relaxation dynamics of maximally clustered networks

We study the relaxation dynamics of fully clustered networks (maximal number of triangles) to an unclustered state under two different edge dynamics---the double-edge swap, corresponding to degree-preserving randomization of the configuration model, and single edge replacement, corresponding to full randomization of the Erd\H{o}s--R\'enyi random graph. We derive expressions for the time evolution of the degree distribution, edge multiplicity distribution and clustering coefficient. We show that under both dynamics networks undergo a continuous phase transition in which a giant connected component is formed. We calculate the position of the phase transition analytically using the Erd\H{o}s--R\'enyi phenomenology

Book Forum: Austro-Hungarian War Aims in the Balkans during World War I

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