Pulsed Plasma Thruster Technology for Small Satellite Missions

Pulsed plasma thrusters (PPT's) offer the combined benefits of extremely low average electric power requirements (1 to 150 W), high specific impulse (approximately 1000 s), and system simplicity derived from the use of an inert solid propellant. Potential applications range from orbit insertion and maintenance of small satellites to attitude control for large geostationary communications satellites. While PPT's have been used operationally on several spacecraft, there has been no new PPT technology development since the early 1970's. As result of the rapid growth in the small satellite community and the broad range of PPT applications, NASA has initiated a development program with the objective of dramatically reducing the PPT dry mass, increasing PPT performance, and demonstrating a flight ready system by October 1997. This paper presents the results of a series of near-Earth mission studies including both primary and auxiliary propulsion and attitude control functions and reviews the status of NASA's on-going development program

Physiology, behavior, and conservation

Many animal populations are in decline as a result of human activity. Conservation practitioners are attempting to prevent further declines and loss of biodiversity as well as to facilitate recovery of endangered species, and they often rely on interdisciplinary approaches to generate conservation solutions. Two recent interfaces in conservation science involve animal behavior (i.e., conservation behavior) and physiology (i.e., conservation physiology). To date, these interfaces have been considered separate entities, but from both pragmatic and biological perspectives, there is merit in better integrating behavior and physiology to address applied conservation problems and to inform resource management. Although there are some institutional, conceptual, methodological, and communication-oriented challenges to integrating behavior and physiology to inform conservation actions, most of these barriers can be overcome. Through outlining several successful examples that integrate these disciplines, we conclude that physiology and behavior can together generate meaningful data to support animal conservation and management actions. Tangentially, applied conservation and management problems can, in turn, also help advance and reinvigorate the fundamental disciplines of animal physiology and behavior by providing advanced natural experiments that challenge traditional frameworks

Mammal responses to global changes in human activity vary by trophic group and landscape

Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amount and timing of animal activity varied widely. Under higher human activity, mammals were less active in undeveloped areas but unexpectedly more active in developed areas while exhibiting greater nocturnality. Carnivores were most sensitive, showing the strongest decreases in activity and greatest increases in nocturnality. Wildlife managers must consider how habituation and uneven sensitivity across species may cause fundamental differences in human–wildlife interactions along gradients of human influence.Peer reviewe

Quantitative temporal viromics: an approach to investigate host-pathogen interaction

A systematic quantitative analysis of temporal changes in host and viral proteins throughout the course of a productive infection could provide dynamic insights into virus-host interaction. We developed a proteomic technique called “quantitative temporal viromics” (QTV), which employs multiplexed tandem-mass-tag-based mass spectrometry. Human cytomegalovirus (HCMV) is not only an important pathogen but a paradigm of viral immune evasion. QTV detailed how HCMV orchestrates the expression of >8,000 cellular proteins, including 1,200 cell-surface proteins to manipulate signaling pathways and counterintrinsic, innate, and adaptive immune defenses. QTV predicted natural killer and T cell ligands, as well as 29 viral proteins present at the cell surface, potential therapeutic targets. Temporal profiles of >80% of HCMV canonical genes and 14 noncanonical HCMV open reading frames were defined. QTV is a powerful method that can yield important insights into viral infection and is applicable to any virus with a robust in vitro model

Pulmonary Hypertension in COPD: A Case Study and Review of the Literature

Pulmonary hypertension (PH) is a frequently encountered complication of chronic obstructive pulmonary disease (COPD) and is associated with worsened clinical symptoms and prognosis. The prevalence of PH-COPD is not concretely established as classification criteria vary historically, but the presence of severe disease out of proportion to underlying COPD is relatively rare. Right heart catheterization, the gold standard in diagnosis of PH, is infrequently performed in COPD, and the overlap in the clinical symptoms of PH and COPD presents diagnostic challenges. Proven treatments are limited. Trials exploring the use of vasodilator therapy in this patient group generally demonstrate improvements in hemodynamics accompanied by worsening gas exchange without clearly demonstrated improvements in clinically meaningful outcomes. In-depth workup of underlying pulmonary hypertension and use of pulmonary vasodilator medications may be appropriate on an individual basis. We present a case study and a review and discussion of the pertinent literature on this topic

Body condition score accuracy and repeatability from evaluation of cull sow digital images at a midwestern harvest facility

Objective The objective of this study was to assess accuracy, repeatability, and reproducibility when evaluating cull sow body condition score (BCS) using a digital medium. Materials and Methods Selected digital images were sourced from recorded images of sows brought to a Midwest abattoir. Digital images were collected on 2 separate occasions. Each sample, grouped by capture date, represented a unique scoring session. Scorers (n = 6) with experience at assessing sow body condition used images to assign a BCS to each sow using a 7-point BCS scale. Using applied values, scores were adjusted to the standard 5-point scale. Because scorers assessed individual sows’ body condition from recorded video images, the mode score (BCSMode) was calculated for each sow and considered the gold standard. Scoring distributions, mode scores, individual bias, percent agreement with BCSMode, percent interobserver agreement, Spearman correlations evaluating scorer agreement, repeatability, and reproducibility were calculated. Results and Discussion Scorer bias from the pooled cull sow groups (n = 386 total available video images from 2 separate collections) ranged from −0.25 (±0.5) to 0.51 (±0.9). Spearman correlation coefficients for cull sow BCS measured on all sows for all scores during the second scoring round were lower than those observed in the first round. Additionally, it was observed that repeatability estimates improved from round 1 and round 2 (Rd 1 = 0.74 and Rd 2 = 0.76), and reproducibility slightly decreased between round 1 and round 2 (Rd 1 = 0.52 and Rd 2 = 0.47). These repeatability and reproducibility changes demonstrate that as experience level increases, scorers begin to develop their interpretation of the scale used to assess body condition. In turn, they become more repeatable within themselves but may differ from other scorers. Implications and Applications The ability for scorers to accurately identify low-BCS sows could serve as a cumulative lifetime welfare indicator where harvest facilities could provide valuable BCS feedback on individual sow and group average basis. The accuracy, repeatability, and reproducibility reported in this study suggest that digital images are an effective medium to assess cull sow BCS.This is a manuscript of an article published as Taylor, W. E., D. C. Humphrey, B. D. Peyer, A. K. Johnson, J. T. Brown, S. T. Millman, A. L. Chipman, C. J. Cassady, S. M. Lonergan, and K. J. Stalder. "Body condition score accuracy and repeatability from evaluation of cull sow digital images at a midwestern harvest facility." Applied Animal Science 38, no. 6 (2022): 627-638. DOI: 10.15232/aas.2022-02295. Copyright 2022 Elsevier. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). Posted with permission