Continuity properties of vectors realizing points in the classical field of values

For an $n$-by-$n$ matrix $A$, let $f_A$ be its "field of values generating function" defined as $f_A\colon x\mapsto x^*Ax$. We consider two natural versions of the continuity, which we call strong and weak, of $f_A^{-1}$ (which is of course multi-valued) on the field of values $F(A)$. The strong continuity holds, in particular, on the interior of $F(A)$, and at such points $z \in \partial F(A)$ which are either corner points, belong to the relative interior of flat portions of $\partial F(A)$, or whose preimage under $f_A$ is contained in a one-dimensional set. Consequently, $f_A^{-1}$ is continuous in this sense on the whole $F(A)$ for all normal, 2-by-2, and unitarily irreducible 3-by-3 matrices. Nevertheless, we show by example that the strong continuity of $f_A^{-1}$ fails at certain points of $\partial F(A)$ for some (unitarily reducible) 3-by-3 and (unitarily irreducible) 4-by-4 matrices. The weak continuity, in its turn, fails for some unitarily reducible 4-by-4 and untiarily irreducible 6-by-6 matrices.Comment: 9 pages, 2 figures. Linear and Multilinear Algebra 201

Diagnostic Prevalence Rates from Early to Mid Adolescence among Indigenous Adolescents: First Results from a Longitudinal Study

Objective: To investigate change in prevalence rates for mental and substance abuse disorders between early and mid-adolescence among a cohort of indigenous adolescents. Method: The data are from a lagged, sequential study of 651 indigenous adolescents from a single culture in the northern Midwest United States and Canada. At waves 1 (ages 10-12 years) and 4 (ages 13-15 years), one adult caretaker and one tribally enrolled adolescent completed a computer-assisted personal interview that included Diagnostic Interview Schedule for Children- Revised assessment for 11 diagnoses. Multivariate analyses investigate effects of wave 1 adolescent diagnosis and wave 1 biological mother diagnosis (University of Michigan Composite International Diagnostic Interview) on wave 4 diagnostic outcomes. Results: The findings show a increase in prevalence rates for substance abuse disorders and conduct disorders between ages 10 and 12 years and 13 and 15 years among indigenous adolescents, with these disorders affecting more than one fourth of the children. The rate of lifetime conduct disorder is about twice that expected in general population studies (23.4% versus 5%– 10%), and the rate of lifetime substance abuse disorder (27.2%) is three times that reported in the 2004 National Survey on Drug Use and Health (9.4%) for individuals 12 years or older. Prevalence rates for any single mental or substance use disorder (44.8 lifetime) for the 13-to 15-year-olds are similar to the lifetime prevalence rates reported in the National Comorbidity Survey- Replication (46.4%) for individuals 18 years and older. Conclusions: A mental health crisis exists on the indigenous reservations and reserves that participated in this study. Current service systems are overwhelmed and unable to meet the demands placed upon them

Diagnostic Prevalence Rates from Early to Mid Adolescence among Indigenous Adolescents: First Results from a Longitudinal Study

Objective: To investigate change in prevalence rates for mental and substance abuse disorders between early and mid-adolescence among a cohort of indigenous adolescents. Method: The data are from a lagged, sequential study of 651 indigenous adolescents from a single culture in the northern Midwest United States and Canada. At waves 1 (ages 10-12 years) and 4 (ages 13-15 years), one adult caretaker and one tribally enrolled adolescent completed a computer-assisted personal interview that included Diagnostic Interview Schedule for Children- Revised assessment for 11 diagnoses. Multivariate analyses investigate effects of wave 1 adolescent diagnosis and wave 1 biological mother diagnosis (University of Michigan Composite International Diagnostic Interview) on wave 4 diagnostic outcomes. Results: The findings show a increase in prevalence rates for substance abuse disorders and conduct disorders between ages 10 and 12 years and 13 and 15 years among indigenous adolescents, with these disorders affecting more than one fourth of the children. The rate of lifetime conduct disorder is about twice that expected in general population studies (23.4% versus 5%– 10%), and the rate of lifetime substance abuse disorder (27.2%) is three times that reported in the 2004 National Survey on Drug Use and Health (9.4%) for individuals 12 years or older. Prevalence rates for any single mental or substance use disorder (44.8 lifetime) for the 13-to 15-year-olds are similar to the lifetime prevalence rates reported in the National Comorbidity Survey- Replication (46.4%) for individuals 18 years and older. Conclusions: A mental health crisis exists on the indigenous reservations and reserves that participated in this study. Current service systems are overwhelmed and unable to meet the demands placed upon them

Mental Disorder, Subsistence Strategies, and Victimization among Gay, Lesbian, and Bisexual Homeless and Runaway Adolescents

This study compares participation in deviant subsistence strategies, street victimization, and lifetime prevalence of five mental disorders (conduct disorder, major depressive disorder, post-traumatic stress disorder, alcohol abuse, and drug abuse) among heterosexual males and females (n = 366) and gay, lesbian, and bisexual (n = 63) homeless and runaway adolescents from the first wave of a longitudinal study of homeless youth in four Midwestern states. The results indicate that gay, lesbian, and bi¬sexual adolescents were more likely to have been physically and sexually abused by caretakers, were more likely to engage in risky survival strategies when on their own (including survival sex), were more likely to be physically and sexually victimized when on the streets, and were more likely to meet criteria for mental disorder than were their heterosexual counterparts

A Technical Roadmap for Autonomy for Marine Future Vertical Lift (FVL)

NPS NRP Executive SummaryThe Marines desire to leverage automation in their next Future Vertical Lift (FVL) platform, meaning they must define the human-FVL teaming interactions. The FVL will operate in a wide spectrum of flight regimes, from remotely piloted, to fully manned, to mostly automatic, and in combinations of the above. This broadened operating approach necessitates that understanding the various human machine teaming interdependent interactions across this diverse operating spectrum be completely delineated. NPS is well positioned to assist. Three approaches are considered: Use Co-active Design, since it is a rigorous engineering process that captures these interactions and interdependencies, develops workflows, and identifies resilient paths for human machine teaming using interdependence analysis (IA); define an FVL 'Living Lab' (LL) that the FVL program management office (PMO) could use to explore technical and concept tradeoffs; establish the cost/benefit relationships of these approaches; and design approaches to developing trust within this operating framework. The topic sponsor desires these techniques so as to create a PMO that decreases the speed at which technical tradeoffs can be identified and made.HQMC Aviation (AVN)This research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.

A Technical Roadmap for Autonomy for Marine Future Vertical Lift (FVL)

NPS NRP Project PosterThe Marines desire to leverage automation in their next Future Vertical Lift (FVL) platform, meaning they must define the human-FVL teaming interactions. The FVL will operate in a wide spectrum of flight regimes, from remotely piloted, to fully manned, to mostly automatic, and in combinations of the above. This broadened operating approach necessitates that understanding the various human machine teaming interdependent interactions across this diverse operating spectrum be completely delineated. NPS is well positioned to assist. Three approaches are considered: Use Co-active Design, since it is a rigorous engineering process that captures these interactions and interdependencies, develops workflows, and identifies resilient paths for human machine teaming using interdependence analysis (IA); define an FVL 'Living Lab' (LL) that the FVL program management office (PMO) could use to explore technical and concept tradeoffs; establish the cost/benefit relationships of these approaches; and design approaches to developing trust within this operating framework. The topic sponsor desires these techniques so as to create a PMO that decreases the speed at which technical tradeoffs can be identified and made.HQMC Aviation (AVN)This research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.

High power Nb-doped LiFePO₄ Li-ion battery cathodes; pilot-scale synthesis and electrochemical properties

AbstractHigh power, phase-pure Nb-doped LiFePO4 (LFP) nanoparticles are synthesised using a pilot-scale continuous hydrothermal flow synthesis process (production rate of 6 kg per day) in the range 0.01–2.00 at% Nb with respect to total transition metal content. EDS analysis suggests that Nb is homogeneously distributed throughout the structure. The addition of fructose as a reagent in the hydrothermal flow process, followed by a post synthesis heat-treatment, affords a continuous graphitic carbon coating on the particle surfaces. Electrochemical testing reveals that cycling performance improves with increasing dopant concentration, up to a maximum of 1.0 at% Nb, for which point a specific capacity of 110 mAh g−1 is obtained at 10 C (6 min for the charge or discharge). This is an excellent result for a high power cathode LFP based material, particularly when considering the synthesis was performed on a large pilot-scale apparatus

Auxotrophic interactions: A stabilizing attribute of aquatic microbial communities?

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Johnson, W. M., Alexander, H., Bier, R. L., Miller, D. R., Muscarella, M. E., Pitz, K. J., & Smith, H. Auxotrophic interactions: A stabilizing attribute of aquatic microbial communities? FEMS Microbiology Ecology, (2020): fiaa115, doi: 10.1093/femsec/fiaa115.Auxotrophy, or an organism's requirement for an exogenous source of an organic molecule, is widespread throughout species and ecosystems. Auxotrophy can result in obligate interactions between organisms, influencing ecosystem structure and community composition. We explore how auxotrophy-induced interactions between aquatic microorganisms affect microbial community structure and stability. While some studies have documented auxotrophy in aquatic microorganisms, these studies are not widespread, and we therefore do not know the full extent of auxotrophic interactions in aquatic environments. Current theoretical and experimental work suggests that auxotrophy links microbial community members through a complex web of metabolic dependencies. We discuss the proposed ways in which auxotrophy may enhance or undermine the stability of aquatic microbial communities, highlighting areas where our limited understanding of these interactions prevents us from being able to predict the ecological implications of auxotrophy. Finally, we examine an example of auxotrophy in harmful algal blooms to place this often theoretical discussion in a field context where auxotrophy may have implications for the development and robustness of algal bloom communities. We seek to draw attention to the relationship between auxotrophy and community stability in an effort to encourage further field and theoretical work that explores the underlying principles of microbial interactions.This work was supported by the National Science Foundation [OCE-1356192]

Host Species and Captivity Distinguish the Microbiome Compositions of a Diverse Zoo-Resident Non-Human Primate Population

Vast numbers of microorganisms inhabit the mammalian gastrointestinal tract in a complex community referred to as the gut microbiome. An individual’s microbiome may be impacted by genetics, diet, and various environmental factors, and has been associated with many health states and diseases, though specific explanations are lacking. While these communities are well-studied in human populations, non-human primates (NHPs), in particular zoo-resident or captive NHPs, offer distinct advantages to increasing our understanding of factors that influence gut microbiome composition. Here, we characterize the gut microbiome composition of a phylogenetically diverse cohort of NHPs residing in the same urban zoo. We show that despite overlapping and controlled environmental contexts, gut microbiomes are still distinguished between NHP host species. However, when comparing the zoo cohort to wild NHPs, we show that captivity status strongly distinguishes zoo-resident NHPs from their wild counterparts, regardless of host phylogeny. Microbial orders unique to captive NHPs include taxa commonly present in human gut microbiomes. Together, these results demonstrate that differences between NHP species are strongly associated with gut microbiome composition and diversity, suggesting that species-specific approaches should be considered when investigating environmental factors’ influence on gut microbiome composition