University of Colorado System

Abstract Post-mission disposal (PMD) non-compliance is a major threat to the long-term sustainability of Low Earth Orbit (LEO). From 2010–2024, only 40% of satellites in non-naturally compliant orbits successfully deorbited. With launch rates rising rapidly and large constellations expanding the active population, reducing the number of long-lived derelicts is increasingly urgent. We evaluate an escrow-based PMD performance bond on satellite operators, designed to increase disposal compliance by making non-compliance financially costly while preserving access to orbit. The analysis uses an integrated assessment framework that couples an economic decision-making model for satellite operators with a model for the evolution of the space object populations in LEO, enabling launch decisions and debris risk to co-evolve endogenously over a 25-year horizon. Results show that bonds of $200k per satellite can reduce the mass of derelict satellite per year by more than one-third and increase welfare by up to 27%. Bonds greater than $1 million exhibit diminishing marginal returns. We also examine partial bond adoption and market leakage and find that a bond that only covers 20% of the global market can still achieve meaningful derelict reductions and space sustainability improvements. Broader participation improves both environmental and economic welfare outcomes.

PKMζ, a persistently active atypical PKC (aPKC) isoform, is thought to maintain late-phase long-term potentiation (late-LTP) and long-term memory. However, PKMζ-knockout mice still exhibit hippocampal LTP and spatial memory while lacking neocortical LTP, questioning whether this kinase is fundamental to enduring synaptic potentiation and memory. Tsokas et al. (2016) showed the other aPKC, PKCι/λ, likely compensates for PKMζ during maintenance in the hippocampus of PKMζ-null mice. In wild-type mice, PKCι/λ drives early-LTP and short-term memory, while PKMζ compensates for PKCι/λ knockout by supporting both early- and late-phase processes. Here we show PKCι/λ persistently increases during maintenance in two mouse models: PKMζ-conditional knockout (cKO) mice, and double-knockout mice carrying both conditional deletion of PKCι/λ and constitutive loss of PKMζ. In the double-knockout mice, PKCι/λ was measured while the kinase was still present, prior to its inducible ablation, to characterize its compensatory upregulation in late-LTP before removal. To test whether this compensation was functional, we ablated PKCι/λ in the hippocampus of the double-knockout mice. The double-knockout eliminated late-LTP, whereas individual knockout of either aPKC alone showed normal-appearing LTP. Double-knockout also abolished spatial long-term memory without affecting short-term memory. Thus, when PKMζ is absent, PKCι/λ persists to maintain hippocampal late-LTP and long-term memory.

Prescription drug promotion by social media influencers (hereinafter influencers) is a growing phenomenon that raises concerns about misleading advice, insufficient regulatory oversight, and ethically problematic marketing practices. Understanding the scope and risks of influencers' promotional activities is essential to protect public health. To systematically review existing research on influencer prescription drug promotion, with a focus on identifying recurring themes, regulatory gaps, and opportunities for intervention. This systematic scoping review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline. The search strategy was developed with a health sciences librarian and preregistered on Open Science Framework. English-language articles from peer-reviewed journals were retrieved from the Medline, Communication & Mass Media Complete, CINAHL Complete, PsycInfo, Web of Science, Business Source Complete, Scopus, and Cochrane Library databases, covering research conducted in diverse online and health care contexts worldwide from 2004 to 2024. Searches used key terms related to influencers, social media, and prescription drugs, completed on March 13, 2024. Included studies underwent thematic analysis. The primary outcomes included concerns related to accuracy (misinformation), transparency (disclosure practices), and persuasiveness (personal and parasocial narratives) of prescription drug promotion by influencers. Twelve articles met inclusion criteria (8 empirical and 4 theoretical), addressing topics such as contraceptive advertising, performance-enhancing drugs, and broader pharmaceutical promotion. Methods included content analyses, interviews, and experiments. Three recurring themes emerged: (1) misinformation stemming from influencers' limited expertise in the context of audiences' low health literacy; (2) weak regulatory oversight and inconsistent disclosure practices; and (3) parasocial narratives that blur distinctions between personal testimony and paid promotion. This systematic scoping review study of prescription drug promotion by influencers found that such promotion carried risks of inaccurate or misleading advice, often amplified through personal and emotionally resonant narratives in an environment with limited oversight and enforcement. Despite the small and fragmented evidence base, these findings highlight the urgent need for updated regulatory guidance, standardized and enforceable disclosure requirements, stronger platform accountability, and targeted digital literacy initiatives. Policymakers and researchers should act proactively to safeguard public health.