High‐latitude ionospheric convection models derived from Defense Meteorological Satellite Program ion drift observations and parameterized by the interplanetary magnetic field strength and direction

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95111/1/jgra16194.pd

MANAGING THE WEAR OF HEAVY CONSTRUCTION EQUIPMENT STEEL TRACK UNDERCARRIAGE BY SOIL SAND CONTENT

Heavy construction equipment owners and managers have few predictive tools that can estimate wear rate of undercarriage track propulsion systems working in various soil types and changing operational conditions. Managing the timely maintenance of these track systems is critical for they represent over half of the non-fuel operating cost of the equipment fleet. Understanding the major influencing factors that impact undercarriage system wear rate can help determine the most economical time to stop a machine for track maintenance thus positively impacting the equipment’s return on investment (ROI). This research analyzed the population of track type dozers in the eastern half of North Carolina, United States of America. This region has markedly different soil types, topography and precipitation amounts making this to be an excellent study canvas. Sand percentage in the soil where the machine is working is thought to be a primary factor influencing the wear rate. In addition, other factors like precipitation, temperature, machine model, machine weight, altitude above sea level, and work type code are also considered and analyzed to determine which of these factors have significance. A regression model is developed that can be used as a predictive model to help manage this high value maintenance wear item. This research is important because the results can assist machine owners in maximizing the life of the undercarriage system in eastern North Carolina and will result in better machine maintenance decisions. In addition, this research can be utilized to accurately bid construction jobs predicting machine operating expense for each specific job site soil makeup

Summary of Space Environment Magnetometer and Particle Replacement Experiment (SEMPRE) Study

As part of the GOES-R series follow on architecture study following the NOAA Satellite Observing System Architecture (NSOSA) study, a study team evaluated the feasibility of accommodating the GOES in-situ instruments (Magnetometer and Particle Detectors) on a dedicated spacecraft with no impact to the overall baseline mission cost assuming two large observatories. The accommodations cost on a primary operational type observatory are non-negligible requiring: a large non-magnetic boom to reduce the impact of the spacecraft interference on the magnetometer; and strict contamination control and magnetic cleanliness to prevent magnetic contamination near the magnetometers. These, along with the additional interface complexities greatly increase the cost of larger spacecraft by extending integration time with a large marching army. By contrast, a dedicated mission provides flexibility in location and refresh rate not afforded when these sensors are launched as secondary payloads. This study performed an informal industry survey of small form-factor instruments currently flying or in process of being developed. The study identified three potential particle detector suites and multiple magnetometers that will satisfy the requirements while having low enough volume and mass to allow accommodation on a rideshare class spacecraft. Using the largest of the identified particle detector suites, the Goddard Space Flight Center Mission Design Lab developed a design for a rideshare spacecraft that will accommodate the particle detector suite and magnetometer. The cost of the spacecraft, based on multiple cost models, is comparable to the cost of accommodating the magnetometer and particle detector suite on two (East and West) larger main observatories

Integrated Models of Care for Individuals with Opioid Use Disorder: How Do We Prevent HIV and HCV?

Purpose of Review To describe models of integrated and co-located care for opioid use disorder (OUD), hepatitis C (HCV), and HIV. Recent Findings The design and scale-up of multidisciplinary care models that engage, retain, and treat individuals with HIV, HCV, and OUD are critical to preventing continued spread of HIV and HCV. We identified 17 models within primary care (N = 3), HIV specialty care (N = 5), opioid treatment programs (N = 6), transitional clinics (N = 2), and community-based harm reduction programs (N = 1), as well as two emerging models. Summary Key components of such models are the provision of (1) medication-assisted treatment for OUD, (2) HIV and HCV treatment, (3) HIV pre-exposure prophylaxis, and (4) behavioral health services. Research is needed to understand differences in effectiveness between co-located and fully integrated care, combat the deleterious racial and ethnic legacies of the “War on Drugs,” and inform the delivery of psychiatric care. Increased access to harm reduction services is crucial

The dynamic cusp at low altitudes: A case study combining Viking, DMSP, and Sondrestrom incoherent scatter radar observations

A case study involving data from three satellites and a ground-based radar are presented. Focus is on a detailed discussion of observations of the dynamic cusp made on 24 Sep. 1986 in the dayside high-latitude ionosphere and interior magnetosphere. The relevant data from space-borne and ground-based sensors is presented. They include in-situ particle and field measurements from the DMSP-F7 and Viking spacecraft and Sondrestrom radar observations of the ionosphere. These data are augmented by observations of the IMF and the solar wind plasma. The observations are compared with predictions about the ionospheric response to the observed particle precipitation, obtained from an auroral model. It is shown that observations and model calculations fit well and provide a picture of the ionospheric footprint of the cusp in an invariant latitude versus local time frame. The combination of Viking, Sondrestrom radar, and IMP-8 data suggests that we observed an ionospheric signature of the dynamic cusp. Its spatial variation over time which appeared closely related to the southward component of the IMF was monitored

Interhemispheric asymmetry of the high‐latitude ionospheric convection on 11–12 May 1999

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95394/1/jgra16830.pd

Densely sampled phylogenies frequently deviate from maximum parsimony in simple and local ways

Why do phylogenetic algorithms fail when they return incorrect answers? This simple question has not been answered in detail, even for maximum parsimony (MP), the simplest phylogenetic criterion. Understanding MP has recently gained relevance in the regime of extremely dense sampling, where each virus sample commonly differs by zero or one mutation from another previously sampled virus. Although recent research shows that evolutionary histories in this regime are close to being maximally parsimonious, the structure of their deviations from MP is not yet understood. In this paper, we develop algorithms to understand how the correct tree deviates from being MP in the densely sampled case. By applying these algorithms to simulations that realistically mimic the evolution of SARS-CoV-2, we find that simulated trees frequently only deviate from maximally parsimonious trees locally, through simple structures consisting of the same mutation appearing independently on sister branches.Comment: 18 pages, 7 figures, submitted to RECOMB 202