Publications by authors named "John R Marshall"

A major unknown in the field of planetary protection is the degree to which natural atmospheric processes remove terrestrial microorganisms from robotic and crewed spacecraft that could potentially contaminate Mars (i.e., forward contamination).

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Article Synopsis
  • * Traditional methods of assessing OSR flower production are slow and subjective, but a new technique using drones and multispectral imaging allows for faster, more accurate data collection on crop growth and flower numbers.
  • * By using a simplified index to analyze flower production, researchers found a strong correlation between their yield estimates and actual yields, proving this method can effectively predict OSR seed yield three months before harvest.
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: Reports indicate a geographic effect of socioeconomic inequalities on the occurrence of opioid-related fatal overdoses. This study aims to (1) estimate the rates of opioid-related overdoses, (2) estimate the association of benzodiazepine co-ingestion with opioid-related deaths, (3) estimate associations between socioeconomic indicators and opioid-related deaths, and (4) map the distribution of fatal overdoses, in Orange County (OC), California. : An ecologic study was conducted of all opioid- related deaths (1205 total) from 2010 to 2014 obtained from the OC Coroner Division database (1065 OC residents, 55 nonresidents, 85 OC homeless) (analyzed 2016-2017).

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Introduction: Given the nationwide increase in emergency department (ED) visits it is of paramount importance for hospitals to find efficient ways to manage patient flow. The purpose of this study was to determine whether there is a significant difference in success rates, length of stay (LOS), and other demographic factors in two cohorts of patients admitted directly to an ED observation unit (EDOU) under an abdominal pain protocol by a physician in triage (bypassing the main ED) versus those admitted via the traditional pathway (evaluated and treated in the main ED prior to EDOU admission).

Methods: This was a retrospective cohort study of patients admitted to a protocol-driven EDOU with a diagnosis of abdominal pain in a single university hospital center ED.

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The Centers for Disease Control and Prevention (CDC) has published significant data and trends related to the rising epidemic of usage of alternate forms of tobacco among the nation's youth. For the first time ever, the use of the electronic cigarette (e-cigarrette) has surpassed traditional cigarette usage in adolescents. E-cigarettes are battery-operated products designed to deliver aerosolized nicotine and other flavors to the consumer.

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Titan, the largest satellite of Saturn, exhibits extensive aeolian, that is, wind-formed, dunes, features previously identified exclusively on Earth, Mars and Venus. Wind tunnel data collected under ambient and planetary-analogue conditions inform our models of aeolian processes on the terrestrial planets. However, the accuracy of these widely used formulations in predicting the threshold wind speeds required to move sand by saltation, or by short bounces, has not been tested under conditions relevant for non-terrestrial planets.

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Approximately 10% of men in their 70s and 33% of men in their 80s report at least 1 episode of acute urinary retention, and this urological emergency presents unique assessment and treatment challenges in the emergency department setting. Patients presenting with acute urinary retention are often in severe pain and require urgent diagnosis and prompt treatment. The differential diagnosis of acute urinary retention is vast, with some causes leading to permanent impairment if not dealt with in a timely manner.

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Purpose: Recent developments in genomics have led to expanded carrier screening panels capable of assessing hundreds of causal mutations for genetic disease. This new technology enables simultaneous measurement of carrier frequencies for many diseases. As the resultant rank-ordering of carrier frequencies impacts the design and prioritization of screening programs, the accuracy of this ranking is a public health concern.

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Quartz sand surface texture analysis has been automated for the first time for forensic application. The derived Basic Image Features (BIFs) provide computer-generated texture recognition from preexisting data sets. The technique was applied to two distinct classification problems; first, the ability of the system to discriminate between (quartz) sand grains with upturned plate features (indicative of eolian, global sand sea environments) and grains that do not exhibit these features.

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Objective: To determine women's healthcare providers' knowledge and attitudes regarding genetic disorders and expanded genetic screening.

Design: Survey of American Society for Reproductive Medicine 2010 and American College of Obstetricians and Gynecologists 2011 Annual Meeting attendees. The survey included 60 items (12 demographic, 10 knowledge, and 38 attitude).

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Background: Vascular injury during laparoscopic surgery typically occurs with the blind insertion of either the Veress needle or the trocar. We report an aortic puncture from the use of a laparoscopic fascial closure device.

Case: After a laparoscopic-assisted vaginal hysterectomy and during closure of the 10-mm umbilical port with a fascial closure device, attempted passage of the needle encountered unusual resistance in the abdominal wall.

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Laboratory studies, numerical simulations, and desert field tests indicate that aeolian dust transport can generate atmospheric electricity via contact electrification or "triboelectricity." In convective structures such as dust devils and dust storms, grain stratification leads to macroscopic charge separations and gives rise to an overall electric dipole moment in the aeolian feature, similar in nature to the dipolar electric field generated in terrestrial thunderstorms. Previous numerical simulations indicate that these storm electric fields on Mars can approach the ambient breakdown field strength of approximately 25 kV/m.

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We investigate a new mechanism for producing oxidants, especially hydrogen peroxide (H2O2), on Mars. Large-scale electrostatic fields generated by charged sand and dust in the martian dust devils and storms, as well as during normal saltation, can induce chemical changes near and above the surface of Mars. The most dramatic effect is found in the production of H2O2 whose atmospheric abundance in the "vapor" phase can exceed 200 times that produced by photochemistry alone.

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Treatment with anti-inflammatory drugs and the analgesic efficacy of conventional nonsteroidal anti-inflammatory drugs (NSAIDs) are compromised by a two- to fourfold increased risk of gastrointestinal complications. This increased risk has resulted in an increasing use of the new selective cyclooxygenase-2 inhibitors or coxibs, which, in clinical trials and outcomes studies, reduced gastrointestinal adverse events by 50% to 65% compared with conventional NSAIDs. However, the coxibs are not available to all patients who need them, and NSAIDs are still widely used.

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