Evidence for a rapid decrease in Pluto's atmospheric pressure revealed by a stellar occultation in 2019

We report observations of a stellar occultation by Pluto on 2019 July 17. A single-chord high-speed (time resolution $= 2\,$s) photometry dataset was obtained with a CMOS camera mounted on the Tohoku University 60 cm telescope (Haleakala, Hawaii). The occultation light curve is satisfactorily fitted to an existing Pluto's atmospheric model. We find the lowest pressure value at a reference radius of $r = 1215~{\rm km}$ among those reported after 2012, indicating a possible rapid (approximately $21^{+4}_{-5} \%$ of the previous value) pressure drop between 2016 (the latest reported estimate) and 2019. However, this drop is detected at a $2.4\sigma$ level only and still requires confirmation from future observations. If real, this trend is opposite to the monotonic increase of Pluto's atmospheric pressure reported by previous studies. The observed decrease trend is possibly caused by ongoing ${\rm N_2}$ condensation processes in the Sputnik Planitia glacier associated with an orbitally driven decline of solar insolation, as predicted by previous theoretical models. However, the observed amplitude of the pressure decrease is larger than the model predictions.Comment: 7 pages, 3 figures, accepted for publication in Astronomy and Astrophysic

Epigenetic inheritance of an inducibly nucleosome-depleted promoter and its associated transcriptional state in the apparent absence of transcriptional activators

<p>Abstract</p> <p>Background</p> <p>Dynamic changes to the chromatin structure play a critical role in transcriptional regulation. This is exemplified by the Spt6-mediated histone deposition on to histone-depleted promoters that results in displacement of the general transcriptional machinery during transcriptional repression.</p> <p>Results</p> <p>Using the yeast <it>PHO5 </it>promoter as a model, we have previously shown that blocking Spt6-mediated histone deposition on to the promoter leads to persistent transcription in the apparent absence of transcriptional activators <it>in vivo</it>. We now show that the nucleosome-depleted <it>PHO5 </it>promoter and its associated transcriptionally active state can be inherited through DNA replication even in the absence of transcriptional activators. Transcriptional reinitiation from the nucleosome-depleted <it>PHO5 </it>promoter in the apparent absence of activators <it>in vivo </it>does not require Mediator. Notably, the epigenetic inheritance of the nucleosome-depleted <it>PHO5 </it>promoter through DNA replication does not require ongoing transcription.</p> <p>Conclusion</p> <p>Our results suggest that there may be a memory or an epigenetic mark on the nucleosome-depleted <it>PHO5 </it>promoter that is independent of the transcription apparatus and maintains the promoter in a nucleosome-depleted state through DNA replication.</p

Aktivitas Minyak Dan Serbuk Enam Spesies Tumbuhan Terhadap Peneluran Dan Mortalitas Callosobruchus SP. (Coleoptera: Bruchidae)

Storage pests remain one of the main problems in storage. The pest attacks occur not only in the field, but also in storage. Control should be done to maintain the quality of storedproducts. The environmentally friendly measures should be implemented to avoid negative impacts to the environment and human being. The objective of this research was to study the mortality and oviposition deterrence caused by powder and oil of six plant species against Callosobruchus sp. (Coleoptera: Bruchidae). Flowers of Eugenia aromatica, roots of Vetiveria zizanioides, leaves of Pogostemon cablin, seeds of Ricinus communis, seeds of Foeniculum vulgare, and stems of Cymbopogon citratus were air-dried and milled to yield powder. Oil of six plant species were purchased from local market. Oviposition deterrent bioassay was conducted by no-choice method for both powder and oil, while mortality bioassay was conducted by topical application and residual methods for plant oil only. Several plant species showed high biological activity to Callosobruchus sp. Powder of E. aromatica and oil of V. zizanioides caused high oviposition deterrence, while oil of V. zizanioides and E. aromatica caused high mortality

Extension of holomorphic functions and cohomology classes from non reduced analytic subvarieties

The goal of this survey is to describe some recent results concerning the L 2 extension of holomorphic sections or cohomology classes with values in vector bundles satisfying weak semi-positivity properties. The results presented here are generalized versions of the Ohsawa-Takegoshi extension theorem, and borrow many techniques from the long series of papers by T. Ohsawa. The recent achievement that we want to point out is that the surjectivity property holds true for restriction morphisms to non necessarily reduced subvarieties, provided these are defined as zero varieties of multiplier ideal sheaves. The new idea involved to approach the existence problem is to make use of L 2 approximation in the Bochner-Kodaira technique. The extension results hold under curvature conditions that look pretty optimal. However, a major unsolved problem is to obtain natural (and hopefully best possible) L 2 estimates for the extension in the case of non reduced subvarieties -- the case when Y has singularities or several irreducible components is also a substantial issue.Comment: arXiv admin note: text overlap with arXiv:1703.00292, arXiv:1510.0523

On the growth of the Bergman kernel near an infinite-type point

We study diagonal estimates for the Bergman kernels of certain model domains in $\mathbb{C}^2$ near boundary points that are of infinite type. To do so, we need a mild structural condition on the defining functions of interest that facilitates optimal upper and lower bounds. This is a mild condition; unlike earlier studies of this sort, we are able to make estimates for non-convex pseudoconvex domains as well. This condition quantifies, in some sense, how flat a domain is at an infinite-type boundary point. In this scheme of quantification, the model domains considered below range -- roughly speaking -- from being ``mildly infinite-type'' to very flat at the infinite-type points.Comment: Significant revisions made; simpler estimates; very mild strengthening of the hypotheses on Theorem 1.2 to get much stronger conclusions than in ver.1. To appear in Math. An

High capacitance carbon-based xerogel film produced without critical drying

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in APPLIED PHYSICS LETTERS. 93(19):193112 (2008) and may be found at https://doi.org/10.1063/1.2976684 .ArticleAPPLIED PHYSICS LETTERS. 93(19):193112 (2008)journal articl