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

Data from: Sensitivity to phosphorus limitation increases with ploidy level in a New Zealand snail

Evolutionary and ecological factors that explain natural variation in ploidy level remain poorly understood. One intriguing possibility is that nutrient costs associated with higher per-cell nucleic acid content could differentially influence the fitness of different ploidy levels. Here, we test this hypothesis by determining whether access to phosphorus (P), a main component of nucleic acids, differentially affects growth rate in asexual freshwater snails (Potamopyrgus antipodarum) that differ in ploidy. As expected if larger genomes generate higher dietary P requirements, tetraploid P. antipodarum experienced a more than two-fold greater reduction in growth rate in low- vs. high-P conditions relative to triploids. Mirroring these results, tetraploid P. antipodarum also had a significant reduction in body P content under low P relative to high P, while triploid body P content was unaffected. Taken together, these results set the stage for the possibility that P availability could influence the distribution and relative frequency of P. antipodarum of different ploidy levels. These findings could be applicable to many other animal taxa featuring ploidy-level variation, which includes most mixed sexual/asexual taxa

Phenotypic plasticity of the introduced New Zealand mud snail, Potamopyrgus antipodarum, compared to sympatric native snails.

Phenotypic plasticity is likely to be important in determining the invasive potential of a species, especially if invasive species show greater plasticity or tolerance compared to sympatric native species. Here in two separate experiments we compare reaction norms in response to two environmental variables of two clones of the New Zealand mud snail, Potamopyrgus antipodarum, isolated from the United States, (one invasive and one not yet invasive) with those of two species of native snails that are sympatric with the invader, Fossaria bulimoides group and Physella gyrina group. We placed juvenile snails in environments with high and low conductivity (300 and 800 mS) in one experiment, and raised them at two different temperatures (16 °C and 22 °C) in a second experiment. Growth rate and mortality were measured over the course of 8 weeks. Mortality rates were higher in the native snails compared to P. antipodarum across all treatments, and variation in conductivity influenced mortality. In both experiments, reaction norms did not vary significantly between species. There was little evidence that the success of the introduced species is a result of greater phenotypic plasticity to these variables compared to the sympatric native species

Response to Phosphorus Limitation Varies among Lake Populations of the Freshwater Snail <i>Potamopyrgus antipodarum</i>

<div><p>Local adaptation – typically recognized as higher values of fitness-related traits for native <i>vs</i>. non-native individuals when measured in the native environment - is common in natural populations because of pervasive spatial variation in the intensity and type of natural selection. Although local adaptation has been primarily studied in the context of biotic interactions, widespread variation in abiotic characteristics of environments suggests that local adaptation in response to abiotic factors should also be common. <i>Potamopyrgus antipodarum</i>, a freshwater New Zealand snail that is an important model system for invasion biology and the maintenance of sexual reproduction, exhibits local adaptation to parasites and rate of water flow. As an initial step to determining whether <i>P. antipodarum</i> are also locally adapted to phosphorus availability, we examined whether populations differ in their responses to phosphorus limitation. We found that field-collected juvenile <i>P. antipodarum</i> grew at a lower rate and reached an important size threshold more slowly when fed a relatively low <i>vs</i>. a relatively high- phosphorus diet. We also detected significant across-population variation in individual growth rate. A marginally significant population-by-dietary phosphorus interaction along with a two-fold difference across populations in the extent of suppression of growth by low phosphorus suggests that populations of <i>P. antipodarum</i> may differ in their response to phosphorus limitation. Local adaptation may explain this variation, with the implication that snails from lakes with relatively low phosphorus availability should be less severely affected by phosphorus limitation than snails from lakes with higher phosphorus availability.</p></div

Open space and sustainable development in Jakarta

Development of open space and green areas in Jakarta is essential to ensure the development of the city is sustainable. Current development trends in Jakarta are extremely market oriented and have resulted in many environments and socio-economic problems that are unsustainable and dangerous to the continued existence of the city itself. One of the important factors in this regard is the lack of sufficient open spaces in the city. This paper proposes that the open spaces within private lots be eliminated and replaced by large open spaces or green areas located within the district where such private lots are located, and that the amount of open space provided within planned settlement development be increased. By doing so, environmentally sensitive areas of the city that have already become settlements can be recovered and the need for open space fulfilled, so that the development of the city can be sustained. The paper begins with an introduction of Jakarta\u92s present conditions and physical development trends related to the city\u92s open and green spaces. Currently, open spaces are provided in three forms: those which are municipally owned; those which are mandated to be provided by property developers and those that exist as yards in private lots. This is followed by a discussion and investigation regarding the development and provision of open and green space from the three aforementioned forms, how open and green spaces can be qualitatively and quantitatively increased, and the resultant benefits to the city

More snails attained the 3.0<i>P. antipodarum</i> in the high-P <i>vs</i>. low-P diet treatment (Fisher's exact test, <i>p</i><0.0001).

<p>More snails attained the 3.0<i>P. antipodarum</i> in the high-P <i>vs</i>. low-P diet treatment (Fisher's exact test, <i>p</i><0.0001).</p

Mean SGR of snails in the high-P <i>vs</i>. low-P treatments. Error bars are 95% confidence intervals.

<p><i>Potamopyrgus antipodarum</i> fed the low-P diet grew at a significantly lower rate than snails fed the high-P diet. There were also significant differences in SGR among lakes, driven by significantly higher SGR in Brunner (N = 41) and Selfe (N = 54) snails relative to Hawdon (N = 81; <i>p</i><0.001 for both comparisons) and a marginally significant lake by diet treatment interaction (<i>F</i>_{2, 170} = 2.52, <i>p</i> = 0.083).</p

No evidence for a dilution effect of the non-native snail, Potamopyrgus antipodarum, on native snails.

The dilution effect can occur by a range of mechanisms and results in reduced parasite prevalence in host taxa. In invaded ecosystems, the dilution effect can benefit native species if non-native species, acting as resistant or less competent hosts, reduce rates of parasitic infections in native species. In field experiments, we assessed whether manipulating biomass of the non-native snail, Potamopyrgus antipodarum, caused a dilution effect by reducing trematode infections in three taxa of native snails. In contrast to many studies showing resistant or less competent non-native hosts can "dilute" or reduce infection rates, we found no evidence for a dilution effect reducing infection rates of any of the native snails. We suggest that a dilution effect may not have occurred because most trematode taxa are highly host specific, and thus the trematode transmission stages did not recognize the invasive snail as a possible host. In this case, community composition appears to be important in influencing the dilution effect