The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Genetic structuring among populations of the great egret, Ardea alba egretta, in major Brazilian wetlands

Waterbirds are increasingly affected by climate change and human disturbances to the wetlands on which they roost, forage and breed. The evolutionary response of populations to such changes is influenced by genetic variability and gene flow patterns, which enable long-term survival. Thus, genetic monitoring of waterbird populations can provide valuable information to support conservation measures and management policies for wetlands. This study assessed past and contemporary levels of genetic diversity, estimated effective population sizes (Ne) and investigated gene flow patterns among populations of the great egret, Ardea alba egretta, settled in major Brazilian wetlands. Samples (N = 200) were collected from the northern, central western, south-eastern and southern regions of Brazil. AMOVA, F-statistics, assignment tests, Bayesian clustering analyses and Ne were estimated based on mitochondrial DNA (mtDNA) and microsatellite loci. The populations share most mitochondrial haplotypes, suggesting a common recent past. Mismatch analyses, Fs and D statistics, and SSD and Rg indices indicated significant signs of expansion in most populations. The time since expansion suggests that egrets colonized southern latitudes more recently, probably accompanying the supposed historical environmental changes in South America, with more stable habitats toward equatorial regions. MtDNA F(cyrillic)ST revealed significant differentiation between the northern and both the central western and southern populations. Nuclear loci demonstrated significant structuring between the central western and southern populations, which showed similar effective sizes. Despite the considerable dispersal potential of the great egret, there is limited gene flow among populations located in different Brazilian wetlands. Therefore, colonies from different regions should be preserved, with special attention to the northern populations, whose allelic constitution differs from the other. This approach can be used to genetically monitor similar species in other wetlands or to great egret populations in other regions of the Americas.Fil: Corrêa, Thais Camilo. Universidade Federal de Sao Carlos; BrasilFil: Del Lama, Silvia Nassif. Universidade Federal de Sao Carlos; BrasilFil: de Souza, Juliana Rossi. Universidade Federal de Sao Carlos; BrasilFil: Miño, Carolina Isabel. Universidade Federal de Sao Carlos; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentin