Results 41 to 50 of about 2,956 (261)

On the role of collisions with meteoroids in splitting and acceleration of heliocentric velocity of comets

Open Astronomy, 2020
The hypothesis on the role of the meteoroid impacts in the comet nuclei splitting as well as acceleration of their heliocentric velocity are considered.
Guliyev Ayyub, Guliyev Rustam
doaj   +1 more source

Photocatalytic Water Splitting on the Lunar Surface: Prospects for In Situ Resource Utilization

Advanced Materials Interfaces, EarlyView.
Water has been found in craters on the moon nearby locations which are illuminated >80% of the time. Photocatalysis uses energy from sunlight to drive chemical reactions such as water splitting to produce oxygen and hydrogen. It is a scalable technology that requires lighter equipment and utilizes resources available on the moon. ABSTRACT The discovery
Ranjani Kalyan, Thomas D. Small, Gregory F. Metha, Mahmoud Adel Hamza, Thomas J. O'Dea, Yideng Shen, Cameron J. Shearer   +6 more
wiley   +1 more source

Observational results for eight long-period comets observed far from the Sun [PDF]

, 2013
Context. With this work we start a systematic analysis of the distant activity of several Long Period Comets, in order to investigate the evolution of activity throughout the Solar System and explore differences between comets that pass their perihelion
Mazzotta Epifani, E., Tozzi, G. P., Dall'Ora, M., Mazzotta Epifani, E, PALUMBO, Pasquale, Epifani, E., M. Dall’Ora, Perna, D., Licandro, J., Di Fabrizio, L., Tozzi, G., Palumbo, P., J. Licandro, DELLA CORTE, VINCENZO, P. Palumbo, L. Di Fabrizio, E. Mazzotta Epifani, D. Perna, V. Della Corte, Dall’Ora, M., G. P. Tozzi, Della Corte, V., Snodgrass, C., C. Snodgrass   +23 more
core   +1 more source

Coma Abundances of Volatiles at Small Heliocentric Distances: Compositional Measurements of Long-period Comet C/2020 S3 (Erasmus)

The Astronomical Journal, 2023
We report production rates of H _2 O and nine trace molecules (C _2 H _6 , CH _4 , H _2 CO, CH _3 OH, HCN, NH _3 , C _2 H _2 , OCS, and CO) in long-period comet C/2020 S3 (Erasmus) using the high-resolution, cross-dispersed infrared spectrograph (iSHELL)
Chemeda Ejeta, Erika Gibb, Nathan Roth, Michael A. DiSanti, Neil Dello Russo, Mohammad Saki, Adam J. McKay, Hideyo Kawakita, Younas Khan, Boncho P. Bonev, Ronald J. Vervack Jr., Michael R. Combi   +11 more
doaj   +1 more source

Inhibition of SIRT7 Overcomes Radioresistance in Pancreatic Neuroendocrine Tumors by Reactivating MEN1 Expression

Advanced Science, EarlyView.
Pancreatic neuroendocrine tumors frequently silence MEN1 through epigenetic mechanisms. Here, SIRT7 recruits DNMT1 to the MEN1 promoter, drives hypermethylation, and enhances DNA repair. Inhibiting SIRT7 restores MEN1, reduces MRN complex abundance, impairs double‐strand break repair, and sensitizes PanNET models to radiation, supporting SIRT7 as a ...
Jianyun Jiang, Yan Wang, Yi Qin, Luohai Chen, Xiaowu Xu, Guixiong Fan, Desheng Jing, Miaoyan Wei, Xianjun Yu, Junfeng Xu, Shunrong Ji, Jie Chen   +11 more
wiley   +1 more source

Disintegration of Long-period Comet C/2019 Y4 (ATLAS). II. Postperihelion Remnant Recovery

The Astronomical Journal
We present an investigation into the fate of disrupting near-Sun comet C/2019 Y4 (ATLAS). Imaging observations with the Lowell Discovery Telescope, obtained 3–5 months after the reported disruption and the last sighting, constrained the primary component
Salvatore A. Cordova Quijano, Quanzhi Ye, Michael S. P. Kelley   +2 more
doaj   +1 more source

Is the Hubble Crisis Connected with the Extinction of Dinosaurs?

Universe, 2022
It has recently been suggested that a gravitational transition of the effective Newton’s constant Geff by about 10%, 50–150 Myrs ago could lead to the resolution of both the Hubble crisis and the growth tension of the standard ΛCDM model.
Leandros Perivolaropoulos
doaj   +1 more source

Characteristics of Single Encounters of Long-Periodic Comets With Jupiter [PDF]

Symposium - International Astronomical Union, 1979
Original nearly parabolic orbits of comets are known to be evolved toward short-periodic elliptic orbits as statistical results of hundreds of encounters with Jupiter. There seems to be two methods to handle the process, namely, the method by exact numerical integrations for each orbit (Everhart, 1972) and random walk approach by using probability ...
openaire   +1 more source

β‐Elemene Rescues Radiation‐Induced Enteritis by Orchestrating a Host‐Microbiome Circuit That Fuels Epigenetic DNA Repair

Advanced Science, EarlyView.
This study elucidates that β‐elemene promotes cellular uptake of L. gasseri‐derived lactate by enhancing the membrane translocation of MCT1 in a CD147‐dependent manner. Intracellular lactate, through the lactylation of RBBP4 at the K26 site, recruits EP300 to the promoter regions of downstream genes (POLD1/POLD3), catalyzing H3K27ac modification.
Jiancheng He, Jiapeng Bao, Shukang Deng, Weijie Zang, Haoming Yan, Zihao Zhao, Guangze Zhang, Ruiqing Liu, Junjie Chen, Yilin Hu, Wanjiang Xue   +10 more
wiley   +1 more source

Serendipitous Archival Observations of a New Ultradistant Comet C/2019 E3 (ATLAS)

The Astronomical Journal
We identified a new ultradistant comet C/2019 E3 (ATLAS) exhibiting preperihelion cometary activity at heliocentric distances ≳20 au, making it the fourth member of this population after C/2010 U3 (Boattini), C/2014 UN _271 (Bernardinelli–Bernstein), and
Man-To Hui, Robert Weryk, Marco Micheli, Zhong Huang, Richard Wainscoat   +4 more
doaj   +1 more source