Deepwater Horizon Oil Spill: Highlighted Actions and Issues

This report highlights actions taken and issues raised after the April 20, 2010 explosion on the Deepwater Horizon offshore drilling rig and the resulting oil spill in the Gulf of Mexico

Deepwater Horizon Oil Spill: Highlighted Actions and Issues

This report highlights actions taken and issues raised as a result of the April 20, 2010, explosion on the Deepwater Horizon offshore drilling rig, and the resulting oil spill in the Gulf of Mexico. Readers can access more extensive discussions in various CRS reports, identified at the end of this report

Deepwater Horizon Oil Spill: Highlighted Actions and Issues

This report highlights actions taken and issues raised as a result of the April 20, 2010, explosion on the Deepwater Horizon offshore drilling rig, and the resulting oil spill in the Gulf of Mexico

Seasonal variation of hip fractures in patients with Benign Paroxysmal Positional Vertigo

Introduction: Seasonal variation of benign paroxysmal positional vertigo (BPPV) presentation has been reported, with higher rates of presentation in months associated with times of lower serum vitamin D levels. The purpose of this study was to examine the association between the timing of hip fracture in patients with BPPV. Methods: A retrospective review (2013 to 2019) of adult patients was performed at a tertiary care academic center to identify patients with hip fracture due to ground level fall (ICD-10 code S72) and a previously established diagnosis of vestibular disorder (ICD-10 codes H81-83, A88.1, and R42). Included patients were matched by age and sex to control for patients who had hip fracture without a vestibular diagnosis. Patient charts were reviewed, and demographic and clinical data were extracted related to hip fracture and prior vestibular diagnosis. Groups were subdivided based on whether patients had a hip fracture from January to June versus July to December. Fisher’s exact test was used to evaluate for a difference in seasonal variation between groups. Results: There were 201 patients with vestibular disorders of whom 27 patients carried the diagnosis of BPPV, with a mean age of 80.4 years. The rates of hip fracture among patients with BPPV was higher in the period extending from January to June (63.0%) versus July to December (37.0%), [odds ratio 1.59, 95% CI 0.66-4.00]. The rate of hip fracture was not significantly different between these time periods for the control group (51.7% versus 48.3%) or the vestibular group (53.2% versus 46.8%). Conclusion: These results offer preliminary evidence that, in addition to an increased presentation for BPPV during months associated with decreased serum vitamin D, injuries due to BPPV may be increased as well. The present study is limited by the statistical power afforded by the small number of patients with BPPV and hip fracture that were identified

Retropharyngeal Abscess and Pott’s Disease Due to Tuberculosis: A Case Report

Introduction: Extrapulmonary mycobacterial infection can lead to vertebral spondylitis and osteomyelitis (Pott’s disease). Retropharyngeal abscess with concurrent spinal osteomyelitis is a rare presentation of tuberculosis in the US. Chart review on a patient was completed, and the relevant published literature was reviewed. Case Presentation: A previously healthy 34-year-old male originally from Sudan presented to an outside hospital with a 2-month history of neck pain, sore throat, odynophagia, fevers, and chills. MRI showed a retropharyngeal abscess and suspected cervical spine osteomyelitis. Acid-fast bacillus (AFB) smear was positive from a neck drain specimen, but sputum was negative. Chest imaging did not show findings consistent with pulmonary tuberculosis. He was treated with rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) along with moxifloxacin and linezolid due to concern for possible multidrug resistant tuberculosis and transferred to our center for further care. Culture isolated Mycobacterium tuberculosis. CT neck showed vertebral tuberculous osteomyelitis (Pott’s disease) of C1-C3 with a multiloculated retropharyngeal and prevertebral abscess (Figure 1). The patient was taken to the OR for posterior spinal fusion from occiput to C4 and transoral incision and drainage of the abscess. The post-operative course was uneventful, and moxifloxacin and linezolid were discontinued when Xpert MTB/RIF test revealed rifampin susceptibility. At follow-up the patient’s symptoms had resolved. Patient consent was obtained to utilize this case for educational purposes. Conclusions: This report presents the multidisciplinary treatment of this patient requiring infection control measures and antibiotic therapy by infectious disease, posterior spine fusion by orthopedic surgery, and retropharyngeal abscess drainage by otolaryngology

Greenland freshwater pathways in the sub-Arctic Seas from model experiments with passive tracers

Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 121 (2016): 877–907, doi:10.1002/2015JC011290.Accelerating since the early 1990s, the Greenland Ice Sheet mass loss exerts a significant impact on thermohaline processes in the sub-Arctic seas. Surplus freshwater discharge from Greenland since the 1990s, comparable in volume to the amount of freshwater present during the Great Salinity Anomaly events, could spread and accumulate in the sub-Arctic seas, influencing convective processes there. However, hydrographic observations in the Labrador Sea and the Nordic Seas, where the Greenland freshening signal might be expected to propagate, do not show a persistent freshening in the upper ocean during last two decades. This raises the question of where the surplus Greenland freshwater has propagated. In order to investigate the fate, pathways, and propagation rate of Greenland meltwater in the sub-Arctic seas, several numerical experiments using a passive tracer to track the spreading of Greenland freshwater have been conducted as a part of the Forum for Arctic Ocean Modeling and Observational Synthesis effort. The models show that Greenland freshwater propagates and accumulates in the sub-Arctic seas, although the models disagree on the amount of tracer propagation into the convective regions. Results highlight the differences in simulated physical mechanisms at play in different models and underscore the continued importance of intercomparison studies. It is estimated that surplus Greenland freshwater flux should have caused a salinity decrease by 0.06–0.08 in the sub-Arctic seas in contradiction with the recently observed salinification (by 0.15–0.2) in the region. It is surmised that the increasing salinity of Atlantic Water has obscured the freshening signal.NSERC. Grant Numbers RGPIN 227438-09, RGPIN 04357 and RGPCC 433898; RFBR. Grant Number 13-05-00480, 14-05-00730, and 15-05-02457; NSF Grant Number: PLR-0804010, PLR-1313614, and PLR-12037202016-07-2

Immunohistochemical and Molecular Features of Melanomas Exhibiting Intratumor and Intertumor Histomorphologic Heterogeneity

Melanoma is a heterogeneous neoplasm at the histomorphologic, immunophenotypic, and molecular levels. Melanoma with extreme histomorphologic heterogeneity can pose a diagnostic challenge in which the diagnosis may predominantly rely on its immunophenotypic profile. However, tumor survival and response to therapy are linked to tumor genetic heterogeneity rather than tumor morphology. Therefore, understating the molecular characteristics of such melanomas become indispensable. In this study, DNA was extracted from 11 morphologically distinct regions in eight formalin-fixed, paraffin-embedded melanomas. In each region, mutations in 50 cancer-related genes were tested using next-generation sequencing (NGS). A tumor was considered genetically heterogeneous if at least one non-overlapping mutation was identified either between the histologically distinct regions of the same tumor (intratumor heterogeneity) or among the histologically distinct regions of the paired primary and metastatic tumors within the same patient (intertumor heterogeneity). Our results revealed that genetic heterogeneity existed in all tumors as non-overlapping mutations were detected in every tested tumor (n = 5, 100%; intratumor: n = 2, 40%; intertumor: n = 3, 60%). Conversely, overlapping mutations were also detected in all the tested regions (n = 11, 100%). Melanomas exhibiting histomorphologic heterogeneity are often associated with genetic heterogeneity, which might contribute to tumor survival and poor response to therapy

Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program

The James Webb Space Telescope will revolutionize transiting exoplanet atmospheric science due to its capability for continuous, long-duration observations and its larger collecting area, spectral coverage, and spectral resolution compared to existing space-based facilities. However, it is unclear precisely how well JWST will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. In this article, we describe a prefatory JWST Early Release Science (ERS) program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful future transiting exoplanet characterization programs. We propose a multi-pronged approach wherein one aspect of the program focuses on observing transits of a single target with all of the recommended observing modes to identify and understand potential systematics, compare transmission spectra at overlapping and neighboring wavelength regions, confirm throughputs, and determine overall performances. In our search for transiting exoplanets that are well suited to achieving these goals, we identify 12 objects (dubbed "community targets") that meet our defined criteria. Currently, the most favorable target is WASP-62b because of its large predicted signal size, relatively bright host star, and location in JWST's continuous viewing zone. Since most of the community targets do not have well-characterized atmospheres, we recommend initiating preparatory observing programs to determine the presence of obscuring clouds/hazes within their atmospheres. Measurable spectroscopic features are needed to establish the optimal resolution and wavelength regions for exoplanet characterization. Other initiatives from our proposed ERS program include testing the instrument brightness limits and performing phase-curve observations.(Abridged)Comment: This is a white paper that originated from an open discussion at the Enabling Transiting Exoplanet Science with JWST workshop held November 16 - 18, 2015 at STScI (http://www.stsci.edu/jwst/science/exoplanets). Accepted for publication in PAS

Chimera: A Low Cost Solution to Small Satellite Space Access

In the Proceedings of the 17th Annual AIAA/USU Conference on Small Satellites, UT State University Logan, UT, August 11 -14, 2003.The Chimera rocket was designed to enter the small satellite market by offering an affordable and flexible alternative to the Pegasus launch vehicle. A number of design concepts were evaluated, and one was selected to undergo detailed analysis. This included disciplinary analyses in aerodynamics, propulsion, trajectory, aeroheating, structures, weights, operations, and cost. The baseline vehicle, consisting of a Minuteman 2-2 first stage, a PAM-S second stage, and a new third stage carries a 100 and 50 kg payload to a 700 km altitude, at inclinations of 60° and 110° respectively. At this point a Monte Carlo Simulation was performed to determine how well the system met its price goals. The baseline vehicle fails to meet the desired launch price of $5 million to a reasonable confidence level. However, either the implementation of a cost reduction in the cost of the first stage, or the infusion of appropriate structural and propellant technologies in the design of the third stage, help to make the desired launch price viable