Unidirectional Kondo scattering in layered NbS2

Crystalline defects can modify quantum interactions in solids, causing unintuitive, even favourable, properties such as quantum Hall effect or superconducting vortex pinning. Here we present another example of this notion—an unexpected unidirectional Kondo scattering in single crystals of 2H-NbS2. This manifests as a pronounced low-temperature enhancement in the out-of-plane resistivity and thermopower below 40 K, hidden for the in-plane charge transport. The anomaly can be suppressed by the c-axis-oriented magnetic field, but is unaffected by field applied along the planes. The magnetic moments originate from layers of 1T-NbS2, which inevitably form during the growth, undergoing a charge-density-wave reconstruction with each superlattice cell (David-star-shaped cluster of Nb atoms) hosting a localised spin. Our results demonstrate the unique and highly anisotropic response of a spontaneously formed Kondo-lattice heterostructure, intercalated in a layered conductor.

Highly Directive All-Dielectric Nanoantenna

A highly directive dielectric nanoantenna in an integrated chip may enable faster communication as their low losses and small size overcome the limitation of temperature enhancement and low data transfer rate. We optimize nanoantenna consist of Si-nanoblock in the near-infrared region to efficiently transfer a point dipole light to a highly directive light in the far-field region. We engineer the intrinsic electric and magnetic resonances of a Si-block nanoantenna by modifying and reducing its geometrical symmetry. We realize a pronounced enhancement of directivity by systematically inducing perturbation in the Silicon block so that both its reflection and rotational symmetries are broken. Finally, we retain the traditional method to increase resonance’s coupling to outer space by introducing substrate with an increasing refractive index. We find that the directivity has boosted rapidly.

High temperature perception in leaves promotes vascular regeneration in distant tissues

Cellular regeneration in response to wounding is fundamental to maintain tissue integrity. Various internal factors including hormones and developmental pathways affect wound healing but little is known about how external factors influence regeneration. To better understand how the environment affects regeneration, we investigated the effects of temperature using the horticulturally relevant process of plant grafting. We found that elevated temperatures accelerated vascular regeneration of Arabidopsis thaliana and tomato (Solanum lycopersicum) grafts. Leaves were critical for this effect since blocking auxin transport or mutating PHYTOCHROME INTERACTING FACTOR4 (PIF4) or YUCCA2/5/8/9 in the cotyledons abolished the temperature enhancement. However, these perturbations had no effect upon graft healing at ambient temperatures and mutations in PIF4 did not affect the temperature enhancement of callus formation or tissue adhesion, suggesting that leaf-derived auxin was specific for enhancing vascular regeneration in response to elevated temperatures. Tissue-specific perturbations of auxin response using a BODENLOS (BDL) mutant revealed an asymmetric effect of temperature upon regeneration: the presence of bdl above the cut prevented temperature enhancement whereas the presence of bdl below the cut prevented graft healing regardless of temperature. Promotion of tissue regeneration by elevated temperatures was not specific for graft healing and we found that elevated temperatures accelerated xylem formation between the parasite Phtheirospermum japonicum and host Arabidopsis thaliana, and this effect required shoot-derived auxin from the parasite. Taken together, our results identify a pathway by which elevated temperatures accelerate vascular development which could be of relevance for improving regeneration and better understanding inter-plant vascular connections.

Comparison of Key Characteristics of Remarkable SSW Events in the Southern and Northern Hemisphere

<p>An exceptionally strong sudden stratospheric warming (SSW) in the Southern Hemisphere (SH) during September 2019 was observed. Because SSW in the SH is very rare, comparison with the only recorded major SH SSW is done. According to World Meteorological Organization (WMO) definition, the SSW in 2019 has to be classified as minor. The cause of SSW in 2002 was very strong activity of stationary planetary wave with zonal wave-number (ZW) 2, which reached its maximum when the polar vortex split into two circulations with polar temperature enhancement by 30 K/week and it penetrated deeply to the lower stratosphere and upper troposphere. On the other hand, the minor SSW in 2019 involved an exceptionally strong wave-1 planetary wave and a large polar temperature enhancement by 50.8 K/week, but it affected mainly the middle and upper stratosphere. The strongest SSW in the Northern Hemisphere was observed in 2009. This study provides comparison of two strongest SSW in the SH and the strongest SSW in the NH to show difference between two hemispheres and possible impact to the lower or higher layers.</p>

Comparison of Key Characteristics of Remarkable SSW Events in the Southern and Northern Hemisphere

An exceptionally strong sudden stratospheric warming (SSW) in the Southern Hemisphere (SH) during September 2019 was observed. Because SSW in the SH is very rare, comparison with the only recorded major SH SSW is done. According to World Meteorological Organization (WMO) definition, the SSW in 2019 has to be classified as minor. The cause of SSW in 2002 was very strong activity of stationary planetary wave with zonal wave-number (ZW) 2, which reached its maximum when the polar vortex split into two circulations with polar temperature enhancement by 30 K/week and it penetrated deeply to the lower stratosphere and upper troposphere. On the other hand, the minor SSW in 2019 involved an exceptionally strong wave-1 planetary wave and a large polar temperature enhancement by 50.8 K/week, but it affected mainly the middle and upper stratosphere. The strongest SSW in the Northern Hemisphere was observed in 2009. This study provides comparison of two strongest SSW in the SH and the strongest SSW in the NH to show difference between two hemispheres and possible impact to the lower or higher layers.