Rapid formation methods of arrays of randomly distributed Au and Ag nanoparticles, their morphologies and optical characteristics

By the method of rapid radiation heating (at a speed of 20-25 K/s) of Au and Ag films with a thickness of 4-35 nm to temperatures of 573-693 K in air and in the process of vacuum deposition of silver on heated (up to 700 K at a heating rate of 10 K/s ) glass substrates formed Au and Ag NPs arrays with nanoparticle sizes from several tens to hundreds of nanometers, the position λSPR of which is in the range of 520-597 nm for Au NPs and 424-509 nm for Ag NPs. It is established that the average size of nanoparticles depends on the thickness of gold and silver films and the annealing temperature. The results testify that glass substrates with arrays of randomly distributed gold NPs can be used as effective SERS-substrates for the investigation of Raman spectra of nanosized (50-100 nm) chalcogenide films.

Mercury as the Relic of Earth and Venus Outward Migration

In spite of substantial advancements in simulating planet formation, the planet Mercury’s diminutive mass and isolated orbit and the absence of planets with shorter orbital periods in the solar system continue to befuddle numerical accretion models. Recent studies have shown that if massive embryos (or even giant planet cores) formed early in the innermost parts of the Sun’s gaseous disk, they would have migrated outward. This migration may have reshaped the surface density profile of terrestrial planet-forming material and generated conditions favorable to the formation of Mercury-like planets. Here we continue to develop this model with an updated suite of numerical simulations. We favor a scenario where Earth’s and Venus’s progenitor nuclei form closer to the Sun and subsequently sculpt the Mercury-forming region by migrating toward their modern orbits. This rapid formation of ∼0.5 M ⊕ cores at ∼0.1–0.5 au is consistent with modern high-resolution simulations of planetesimal accretion. In successful realizations, Earth and Venus accrete mostly dry, enstatite chondrite–like material as they migrate, thus providing a simple explanation for the masses of all four terrestrial planets, the inferred isotopic differences between Earth and Mars, and Mercury’s isolated orbit. Furthermore, our models predict that Venus’s composition should be similar to the Earth’s and possibly derived from a larger fraction of dry material. Conversely, Mercury analogs in our simulations attain a range of final compositions.

Physiological Responses of Two Contrasting Kiwifruit (Actinidia spp.) Rootstocks against Waterlogging Stress

Rootstocks from Actinidia valvata are much more tolerant to waterlogging stress than those from Actinidia deliciosa, which are commonly used in kiwifruit production. To date, the tolerance mechanism of A. valvata rootstocks’ adaptation to waterlogging stress has not been well explored. In this study, the responses of KR5 (A. valvata) and ‘Hayward’ (A. deliciosa) to waterlogging stress were compared. Results showed that KR5 plants performed much better than ‘Hayward’ during waterlogging by exhibiting higher net photosynthetic rates in leaves, more rapid formation of adventitious roots at the base of stems, and less severe damage to the main root system. In addition to morphological adaptations, metabolic responses of roots including sufficient sucrose reserves, modulated adjustment of fermentative enzymes, avoidance of excess lactic acid and ethanol accumulation, and promoted accumulation of total amino acids all possibly rendered KR5 plants more tolerant to waterlogging stress compared to ‘Hayward’ plants. Lysine contents of roots under waterlogging stress were increased in ‘Hayward’ and decreased in KR5 compared with their corresponding controls. Overall, our results revealed the morphological and metabolic adaptations of two kiwifruit rootstocks to waterlogging stress, which may be responsible for their genotypic difference in waterlogging tolerance.

The Rapid Formation of Coronal Lines in the Nova V1674 Herculis

The nova V1674 Her (Nova Her 2021) has been reported to have the shortest interval between outburst and coronal line formation of any nova yet observed. We present optical and near-infrared spectroscopy from three epochs ranging from shortly before coronal line formation to shortly after. Taken together with the published results of Woodward et al., they indicate that not only did the coronal lines form very early in the nova’s development, but in going from undetectable to detectable in two days, and undetectable to significant, in six days, they developed very rapidly as well.

Grotian Moments: The Concept

During times of fundamental change, customary international law can form quite abruptly. Scholars have begun to call the paradigm shifts and tipping points that lead to rapid formation of new rules of customary international law ‘Grotian Moments.’ This chapter introduces the concept, explains its appellation, provides historic examples of its application since World War ii, examines its usefulness, and addresses some of the critiques that have been leveled at the notion of accelerated formation of customary international law.