Fiber-Based Laser Transmitter at 1.57 Micrometers for Remote Sensing of Atmospheric Carbon Dioxide from Satellites

Over the past 20 years, NASA Goddard has successfully developed space-based lidar for remote sensing studies of the Earth and planets. The lidar in all missions to date have used diode pumped Nd:YAG laser transmitters. Recently we have been concentrating work on developing integrated path differential absorption (IPDA) lidar to measure greenhouse gases, with the goal of measurements from space. Due to the absorption spectrum of CO2 a fiber-based master oscillator power amplifier (MOPA) laser with a tunable seed source is an attractive laser choice. Fiber-based lasers offer a number of potential advantages for space, but since they are relatively new, challenges exist in developing them. In order to reduce risks for new missions using fiber-based lasers, we developed a 30- month plan to mature the technology of a candidate laser transmitter for space-based CO2 measurements to TRL-6. This work is also intended to reduce development time and costs and increase confidence in future mission success

Alcohol Use Behaviors and Reasons to Abstain From or Limit Drinking Among Medically Vulnerable Youth

BACKGROUND. Youth with chronic medical conditions (YCMC) use alcohol at levels similar to their healthy peers but face elevated risk for adverse health consequences. As salient reasons to abstain from or limit drinking (RALD) among YCMC are unknown, we sought to identify clusters of RALD and test associations with use behaviors. METHODS. Eligible YCMC (ages 9–18) recruited from outpatient clinics reported their use behaviors and importance of potential RALD. Cluster analysis was used to discern RALD patterns, which were examined as predictors of alcohol use using multivariate regression. RESULTS. Among 398 participants, 30.9% reported past year alcohol use. Concerns about impacts on medications, school, and disease status were the most frequently endorsed RALD; prior negative experiences with alcohol and family history were the least frequently endorsed. Five RALD clusters were identified for all YCMC and two for recent drinkers. Compared to the cluster with high endorsement of multiple general and health-related RALD, those predominantly citing concerns about addiction and those not strongly endorsing any RALD consistently reported greater alcohol use. Among recent drinkers, the cluster characterized by low concern across multiple RALD also consistently reported greater alcohol use compared to their counterparts expressing moderate concern. CONCLUSIONS. For YCMC, RALD are complex but endorsement of multiple general and health-related RALD is associated with less use, and health concerns are especially prevalent. More research is needed to understand how salient RALD can inform tailored interventions that aim to delay and reduce substance use and improve health outcomes for YCMC