Sustained fluvial deposition recorded in Mars' Noachian stratigraphic record.

Orbital observation has revealed a rich record of fluvial landforms on Mars, with much of this record dating 3.6-3.0 Ga.

A Diverse Array of Fluvial Depositional Systems in Arabia Terra: Evidence for mid-Noachian to Early Hesperian Rivers on Mars.

Branching to sinuous ridges systems, hundreds of kilometers in length and comprising layered strata, are present across much of Arabia Terra, Mars. These ridges are interpreted as depositional fluvial channels, now preserved as inverted topography. Here we use high-resolution image and topographic data sets to investigate the morphology of these depositional systems and show key examples of their relationships to associated fluvial landforms.

Persistence of intense, climate-driven runoff late in Mars history.

Mars is dry today, but numerous precipitation-fed paleo-rivers are found across the planet's surface. These rivers' existence is a challenge to models of planetary climate evolution. We report results indicating that, for a given catchment area, rivers on Mars were wider than rivers on Earth today.

Melanotic neuroectodermal tumor of infancy: a wolf in sheep's clothing.

Introduction: The melanotic neuroectodermal tumor of infancy (MNTI) is an exceptionally rare neoplasm. Despite their potential for local invasion, MNTI are considered benign neoplasms. Sporadic cases have been reported of MNTI acting in a malignant fashion; however, the majority of these tumors were of extragnathic origin.

Demand for single- and dual-degree oral and maxillofacial surgery residency positions.

Purpose: Currently, no consensus has been reached regarding which track, single- or dual-degree, better prepares a resident for oral and maxillofacial surgery (OMS) practice. It is doubtful that such a consensus will ever exist. The purpose of the present study was to explore the trends in the selection of, and competition for, single- and dual-degree residency positions, with the ultimate goal of determining which degree track is in greater demand among recent applicants.

Bone healing with an in situ-formed bioresorbable polyethylene glycol hydrogel membrane in rabbit calvarial defects.

Objectives: The aims of this study were to test whether or not the application of an in situ-formed synthetic polyethylene glycol hydrogel (PEG) used as a biodegradable membrane for guided bone regeneration with a variety of graft materials and ambient oxygen or hyperbaric oxygen (HBO) environments would result in enhanced bone regeneration, and to observe the histologic and histomorphometric aspects of bone healing of the calvarial defects with and without a PEG membrane.

Study Design: Thirty adult, skeletally mature, male New Zealand white rabbits were randomly divided into 3 groups of 10 animals each. Bilateral 15-mm-diameter critical-size defects were created in the parietal bones of each animal.