Ecological and genetic correlates of long-term population trends in the Park Grass Experiment

The Park Grass Experiment (PGE) is the longest observed set of experimental plant communities in existence. Although the gross composition of the vegetation was at equilibrium over the 60-yr period from 1920 to 1979, annual records show that individual species exhibited a range of dynamics. We tested two hypotheses to explain why some species initially increased nd why subsequently some of these (the outbreak species) decreased gain. The study was designed around eight phylogenetically ndependent contrasts (PICs), each containing related species with ifferent dynamics. Our first hypothesis was that persistent increasers and utbreakers have higher intrinsic rates of natural increase than ontrol species (species without trends), allowing them to spread hen interspecific competition is reduced by drought. This was tested by measuring establishment and seed production of species in ield experiments, with and without interspecific competition. Seed production in outbreak species responded more strongly to release from interspecific competition than it did in either of the ther groups of species. Our second hypothesis was that outbreak species eventually declined because they lacked the genetic variation ecessary to adapt to the novel habitats to which they had initially spread. We tested this by measuring mating systems and genetic diversity in persistent and outbreak species in the PGE. In seven out of seven PICs tested, the outbreak species was more selfing than its persistent relative. There was a significant positive correlation between outcrossing rate and gene diversity. These results support roles for both ecological and genetic traits in long-term dynamics

Laboratory Directed Research and Development Annual Report - Fiscal Year 2000

The projects described in this report represent the Laboratory's investment in its future and are vital to maintaining the ability to develop creative solutions for the scientific and technical challenges faced by DOE and the nation. In accordance with DOE guidelines, the report provides, a) a director's statement, b) an overview of the laboratory's LDRD program, including PNNL's management process and a self-assessment of the program, c) a five-year project funding table, and d) project summaries for each LDRD project

Perceived psychosocial impacts of legalized same-sex marriage: A scoping review of sexual minority adults’ experiences

A growing body of literature provides important insights into the meaning and impact of the right to marry a same-sex partner among sexual minority people. We conducted a scoping review to 1) identify and describe the psychosocial impacts of equal marriage rights among sexual minority adults, and 2) explore sexual minority women (SMW) perceptions of equal marriage rights and whether psychosocial impacts differ by sex. Using Arksey and O’Malley’s framework we reviewed peer-reviewed English-language publications from 2000 through 2019. We searched six databases (PubMed, PsycINFO, CINAHL, Web of Science, JSTOR, and Sociological Abstracts) to identify English language, peer-reviewed journal articles reporting findings from empirical studies with an explicit focus on the experiences and perceived impact of equal marriage rights among sexual minority adults. We found 59 studies that met our inclusion criteria. Studies identified positive psychosocial impacts of same-sex marriage (e.g., increased social acceptance, reduced stigma) across individual, interpersonal (dyad, family), community (sexual minority), and broader societal levels. Studies also found that, despite equal marriage rights, sexual minority stigma persists across these levels. Only a few studies examined differences by sex, and findings were mixed. Research to date has several limitations; for example, it disproportionately represents samples from the U.S. and White populations, and rarely examines differences by sexual or gender identity or other demographic characteristics. There is a need for additional research on the impact of equal marriage rights and same-sex marriage on the health and well-being of diverse sexual minorities across the globe

Optimizing viable leukocyte sampling from the female genital tract for clinical trials: an international multi-site study

BACKGROUND: Functional analysis of mononuclear leukocytes in the female genital mucosa is essential for understanding the immunologic effects of HIV vaccines and microbicides at the site of HIV exposure. However, the best female genital tract sampling technique is unclear. Methods and FINDINGS: We enrolled women from four sites in Africa and the US to compare three genital leukocyte sampling methods: cervicovaginal lavages (CVL), endocervical cytobrushes, and ectocervical biopsies. Absolute yields of mononuclear leukocyte subpopulations were determined by flow cytometric bead-based cell counting. Of the non-invasive sampling types, two combined sequential cytobrushes yielded significantly more viable mononuclear leukocytes than a CVL (p<0.0001). In a subsequent comparison, two cytobrushes yielded as many leukocytes (∼10,000) as one biopsy, with macrophages/monocytes being more prominent in cytobrushes and T lymphocytes in biopsies. Sample yields were consistent between sites. In a subgroup analysis, we observed significant reproducibility between replicate same-day biopsies (r = 0.89, p = 0.0123). Visible red blood cells in cytobrushes increased leukocyte yields more than three-fold (p = 0.0078), but did not change their subpopulation profile, indicating that these leukocytes were still largely derived from the mucosa and not peripheral blood. We also confirmed that many CD4 + T cells in the female genital tract express the α4β7 integrin, an HIV envelope-binding mucosal homing receptor. CONCLUSIONS: CVL sampling recovered the lowest number of viable mononuclear leukocytes. Two cervical cytobrushes yielded comparable total numbers of viable leukocytes to one biopsy, but cytobrushes and biopsies were biased toward macrophages and T lymphocytes, respectively. Our study also established the feasibility of obtaining consistent flow cytometric analyses of isolated genital cells from four study sites in the US and Africa. These data represent an important step towards implementing mucosal cell sampling in international clinical trials of HIV prevention

Twenty year fitness trends in young adults and incidence of prediabetes and diabetes: the CARDIA study

The prospective association between cardiorespiratory fitness (CRF) measured in young adulthood and middle age on development of prediabetes, defined as impaired fasting glucose and/or impaired glucose tolerance, or diabetes by middle age remains unknown. We hypothesised that higher fitness levels would be associated with reduced risk for developing incident prediabetes/diabetes by middle age

A Human Factors Simulation of Required Navigation Performance Converging Approach Procedure

The National Airspace System Human Factors Research and Engineering Group (HFREG) Federal Aviation Administration NAS Human Factors Group William J. Hughes Technical Center Atlantic City International Airport, NJ 08405, assessed a proposed Required Navigation Performance (RNP) procedure into San Francisco International Airport (SFO).RNP technology offers several operational benefits including more efficient utilization of airspace, reduced flying time, and reduced air-to-ground communications. The simulation focused on human factors issues affecting Air Traffic Control Specialists (ATCSs)when operating a converging runway approach procedure into the SFO Runway 28R during reduced visibility conditions. Sixteen ATCSs participated in the simulation that we conducted at the Northern California Terminal Radar Approach Control in December2004. The simulation assessed the controllers\u2019 ability to identify blundering aircraft using an Airport Surveillance Radar-9 (ASR-9)display. It also evaluated the propensity for nuisance breakouts, communications options, No Transgression Zone placement options, and the impact of high traffic levels. The simulation comprised a reaction time task and a series of high fidelity operational scenarios designed to assess the viability of the proposed approach. The study confirmed that monitor controllers identified blundering aircraft accurately and timely when using the ASR-9 display. Sector performance remained high across all conditions, and controllers demonstrated no serious operational deficiencies. Overall, the controllers provided positive ratings and comments regarding the proposed 28R RNP approach and procedure. The simulation resulted in two primary recommendations (a) incorporate Air Traffic procedures for RNP approaches into Federal Aviation Administration Order 7110.65 to ensure that ATCSs receive RNP-specific training and (b) present Flight Management System/RNP equipment information in the data block

Dynamic Resectorization in Air Traffic Control: A Human Factors Perspective

The NAS is a highly structured environment. Structure provides benefits including predictability for the decision-maker, the air traffic controller. When something is unusual, controllers can identify the event as out of the ordinary given their inherent and trained capacity for pattern recognition. The expertise in pattern recognition does not develop quickly. In the current system, it takes En Route controllers an average of about three years to certify as Certified Professional Controllers (CPCs, formerly Full Performance Level). In general, CPCs must learn and checkout on at least six different sectors to certify. There are situations, however, when the usual structure is reduced and the typical patterns do not work. This can happen with weather events and systems outages as examples. Dynamic resectorization offers a tool in these situations to increase the options and promote flexibility. In our current system, traffic managers can resectorize in a very systematic structured way to balance the load and increase the level of structure for controllers. The system of the future may include several types of resectorization supported by automation tools. Limited dynamic resectorization is similar to what is done now but may see more widespread use. Unlimited dynamic resectorization represents a leap into the future with under lying technology that does not exist today. Both approaches raise human factors questions, which should be approached systematically in a proactive manner. The more flexible the system becomes the more dynamic the options will be. Operators will need solid anchors if they are going to be able to efficiently and expediously maintain safe separation between aircraft

Complexity in Airport Traffic Control Towers: A Field Study. Part 2. Controller Strategies and Information Requirements

This two-part field study investigated sources of complexity and their incidence within Federal Aviation Administration Air Traffic Control Towers (ATCTs). Human Factors Specialists from the William J. Hughes Technical Center selected six sites representing a combination of high traffic volume, traffic mix, and/or converging runways. Sixty-two Air Traffic Control Specialists participated in the study, providing ratings and descriptions of the complexity sources from a local- and ground-controller perspective. The first report represented a key step in identifying and characterizing the primary sources of complexity within ATCTs and assessing their relative incidence and importance. The second report identifies the strategies that tower controllers use to mitigate complexity, the types of information that they require, and the sources of this information. The participants reported relying on two to three core strategies, which they supplemented with ad hoc techniques. Results from this field study hold implications for future tower automation equipment design. Future research efforts should systematically investigate tower controller information needs and focus, in particular, on sources such as high traffic volume and frequency congestion, which are among the most prevalent sources of complexity within this environment