Ariel - Volume 9 Number 6

Executive Editor Seth B. Paul Associate Editor Warren J. Ventriglia Business Manager Fredric Jay Matlin University News John Patrick Welch World News George Robert Coar Editorials Editor Steve Levine Features Mark Rubin Sports Editor Eli Saleeby Photo Editor Ken Buckwalter Circulation Victor Onufreiczuk Lee Wugofski Graphics and Art Steve Hulkower Commons Editor Brenda Peterso

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

Biotic interactions between saproxylic insect species

Biotic interactions between saproxylic insect specie

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 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, 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

\u3ci\u3eDrosophila\u3c/i\u3e Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu

Open charm production and asymmetry in ppNe collisions at sNN=\sqrt{s_{\scriptscriptstyle\rm NN}} = 68.5 GeV

A measurement of $D^0$ meson production by the LHCb experiment in its fixed-target configuration is presented. The production of $D^0$ mesons is studied with a beam of 2.5 TeV protons colliding on a gaseous neon target at rest, corresponding to a nucleon-nucleon centre-of-mass energy of $\sqrt{s_{\rm NN}}$ = 68.5 GeV. The $D^0$ and ${\overline D^0}$ production cross-section in $p$Ne collisions in the centre-of-mass rapidity range $y^{\star}\in [-2.29, 0]$ is found to be $\sigma_{D^{0}}^{y^\star \in [-2.29, 0]} = 48.2 \pm 0.3 \pm 4.5 \,\mu\textrm{b/nucleon}$ where the first uncertainty is statistical and the second is systematic. The $D^0-{\overline D^0}$ production asymmetry is also evaluated and suggests a negative trend at large negative $y^{\star}$. The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1$\%$ intrinsic charm and 10$\%$ recombination contributions better describe the data than the other models consideredA measurement of ${{D}} ^0$ meson production by the LHCb experiment in its fixed-target configuration is presented. The production of ${{D}} ^0$ mesons is studied with a beam of 2.5 $\,\text {Te\hspace{-1.00006pt}V}$ protons colliding on a gaseous neon target at rest, corresponding to a nucleon–nucleon centre-of-mass energy of $\sqrt{s_{\scriptscriptstyle \text {NN}}} = 68.5\,\,\text {Ge\hspace{-1.00006pt}V}$. The sum of the ${{D}} ^0$ and ${\hspace{0.0pt}\overline{\hspace{0.0pt}{D}}} {}^0$ production cross-section in $p\text {Ne}$ collisions in the centre-of-mass rapidity range $y^{\star }\in [-2.29, 0]$ is found to be \sigma _{D^{0}}^{y^\star \in [-2.29, 0]} = 48.2 \pm 0.3 \pm 4.5 \,\upmu \text {b}/\text {nucleon} where the first uncertainty is statistical and the second is systematic. The ${{{D}} ^0}-{{\hspace{0.0pt}\overline{\hspace{0.0pt}{D}}} {}^0}$ production asymmetry is also evaluated and suggests a trend towards negative values at large negative $y^{\star }$. The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1$\%$ intrinsic charm and 10$\%$ recombination contributions better describe the data than the other models considered.A measurement of $D^0$ meson production by the LHCb experiment in its fixed-target configuration is presented. The production of $D^0$ mesons is studied with a beam of 2.5 TeV protons colliding on a gaseous neon target at rest, corresponding to a nucleon-nucleon centre-of-mass energy of $\sqrt{s_{\rm NN}}$ = 68.5 GeV. The sum of the $D^0$ and ${\overline D^0}$ production cross-section in $p$Ne collisions in the centre-of-mass rapidity range $y^{\star}\in [-2.29, 0]$ is found to be $\sigma_{D^{0}}^{y^\star \in [-2.29, 0]} = 48.2 \pm 0.3 \pm 4.5 \,\mu\textrm{b/nucleon}$ where the first uncertainty is statistical and the second is systematic. The $D^0-{\overline D^0}$ production asymmetry is also evaluated and suggests a trend towards negative values at large negative $y^{\star}$. The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1$\%$ intrinsic charm and 10$\%$ recombination contributions better describe the data than the other models considered