Location and Analysis of Landslides Along the Lewis Overthrust Fault, Glacier National Park, Montana

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Grizzly Bear Restoration in the North Cascades of Washington

The North Cascades of Washington was one of 6 recovery areas where grizzly bears were known or believed to exist at the time of listing under the Endangered Species Act (ESA) in 1975.  The North Cascades recovery plan identified the need for a National Environmental Policy Act process to evaluate a range of alternatives to restore this grizzly bear population.  In January of 2017 the Draft Grizzly Bear Restoration Plan for the North Cascades Ecosystem was released for public comment by the National Park Service and the U.S. Fish and Wildlife Service.  This plan evaluated four alternatives for population restoration. Alternative A was “No Action” with continued existing management practices focused on improved sanitation, poaching control, motorized access, education, and monitoring to evaluate natural restoration.  Alternative B was “Ecosystem Evaluation Restoration” which would transplant up to 10 grizzly bears to the North Cascades and monitor those individuals for 2 years before deciding whether to proceed with additional releases. Alternative C was “Incremental Restoration” in which 5-7 grizzly bears per year would be transplanted to the North Cascades to achieve an initial population of 25 individuals. Monitoring would determine success of the program and the need for additional releases of bears. Alternative D was “Expedited Restoration” in which 5-7 grizzly bears/year would be transplanted to the North Cascades until a population of approximately 200 individuals was achieved. All action alternatives possess an experimental (ESA 10j) population option. The draft document is available for review and comment through March 14, 2017 at:  https://parkplanning.nps.gov/projectHome.cfm?projectId=4414

Magnetic Resonance-based Response Assessment and Dose Adaptation in Human Papilloma Virus Positive Tumors of the Oropharynx treated with Radiotherapy (MR-ADAPTOR): An R-IDEAL stage 2a-2b/Bayesian phase II trial

Background: Current standard radiotherapy for oropharynx cancer (OPC) is associated with high rates of severe toxicities, shown to adversely impact patients’ quality of life. Given excellent outcomes of human papilloma virus (HPV)-associated OPC and long-term survival of these typically young patients, treatment de-intensification aimed at improving survivorship while maintaining excellent disease control is now a central concern. The recent implementation of magnetic resonance image – guided radiotherapy (MRgRT) systems allows for individual tumor response assessment during treatment and offers possibility of personalized dose-reduction. In this 2-stage Bayesian phase II study, we propose to examine weekly radiotherapy dose-adaptation based on magnetic resonance imaging (MRI) evaluated tumor response. Individual patient’s plan will be designed to optimize dose reduction to organs at risk and minimize locoregional failure probability based on serial MRI during RT. Our primary aim is to assess the non-inferiority of MRgRT dose adaptation for patients with low risk HPV-associated OPC compared to historical control, as measured by Bayesian posterior probability of locoregional control (LRC). Methods: Patients with T1-2 N0-2b (as per AJCC 7th Edition) HPV-positive OPC, with lymph node <3 cm and <10 pack-year smoking history planned for curative radiotherapy alone to a dose of 70 Gy in 33 fractions will be eligible. All patients will undergo pre-treatment MRI and at least weekly intra-treatment MRI. Patients undergoing MRgRT will have weekly adaptation of high dose planning target volume based on gross tumor volume response. The stage 1 of this study will enroll 15 patients to MRgRT dose adaptation. If LRC at 6 months with MRgRT dose adaptation is found sufficiently safe as per the Bayesian model, stage 2 of the protocol will expand enrollment to an additional 60 patients, randomized to either MRgRT or standard IMRT. Discussion: Multiple methods for safe treatment de-escalation in patients with HPV-positive OPC are currently being studied. By leveraging the ability of advanced MRI techniques to visualize tumor and soft tissues through the course of treatment, this protocol proposes a workflow for safe personalized radiation dose-reduction in good responders with radiosensitive tumors, while ensuring tumoricidal dose to more radioresistant tumors. MRgRT dose adaptation could translate in reduced long term radiation toxicities and improved survivorship while maintaining excellent LRC outcomes in favorable OPC. Trial registration: ClinicalTrials.gov ID: NCT03224000; Registration date: 07/21/2017. Keywords: Magnetic resonance imaging guided radiotherapy, Human papilloma virus, Oropharyngeal cancer, Adaptive radiotherap