Magneto-mechanical interplay in spin-polarized point contacts

We investigate the interplay between magnetic and structural dynamics in ferromagnetic atomic point contacts. In particular, we look at the effect of the atomic relaxation on the energy barrier for magnetic domain wall migration and, reversely, at the effect of the magnetic state on the mechanical forces and structural relaxation. We observe changes of the barrier height due to the atomic relaxation up to 200%, suggesting a very strong coupling between the structural and the magnetic degrees of freedom. The reverse interplay is weak, i.e. the magnetic state has little effect on the structural relaxation at equilibrium or under non-equilibrium, current-carrying conditions.Comment: 5 pages, 4 figure

Economic Analysis of Post-Harvest Loss and Marketing Efficiency in Guava (cv. Allahabad safeda) in Karnataka

Post-harvest losses (PHL) in guava (cv. Allahabad safeda) were estimated at the field and retail levels in Karnataka, and impact of this loss on marketing efficiency was studied. Results indicated that the total PHL was 13.29% consisting of field-level loss (9.17%) and retail level loss (4.12%). The producer's share was 51.52% and PHL, when included as an item of cost, reduced the share to 45.80%. PHL also reduced marketing efficiency index from 1.06 to 0.88, thereby indicating the importance of PHL and scope for minimizing it to improve the efficiency of the marketing system in guava

Post harvest loss and marketing of fruits - economic analysis of pink flesh guava in local and distant markets in India

Guava produced in Bengaluru in Karnataka is also transported to distant markets like Cochin in Kerala and Chennai in Tamil Nadu. An assessment of post harvest loss (PHL) was done in these markets. The main marketing channel followed was:Producer PHC Distant Market WS Retailer ConsumerMarketing practices followed in marketing of pink flesh guava and losses occurring at the wholesale (transit) and retailers’ level (storage) in the distant market - Kerala were studied from wholesalers and retailers. The PHL at the wholesalers’ level was observed to be 3.6 per cent mainly due to pressed and crushed fruits during transit. The retail level loss was 4.59 per cent which was mainly due to storage for more than two days resulting in decaying, rotting, yellowing etc. Average price received by the wholesaler was Rs.29.92/kg with a margin of Rs.6.21/kg (20.75%). The retailers received a price of Rs.46.54/kg with a margin of Rs.16.35/kg (35.13%). Marketing practices followed in marketing of pink flesh guava and losses occurring at the wholesale (transit) and retailers’ level (storage) in the distant market - Chennai (Tamil Nadu) were studied with wholesalers in Coimbeedu market and retailers in different parts of Chennai. The PHL at the wholesalers’ level was observed to be 4.62 per cent mainly due to pressed and crushed fruits during transit. The retail level loss was 6.09 per cent which was due to pressing of fruits during handling. The wholesaler received a margin of 22.91 percent in trading of guava fruits. The retailers received a margin of 45.72 per cent. The Karnataka farmers can take advantage of the higher prices prevalent in the distant markets and increase their income. Pathological investigation indicated that losses occurred at different stages of handling due to Styler end rot, Anthracnose, Canker, thrips attack etc., which needs to be addressed. The storage losses of pink flesh guava were estimated as 5.89 % after 4 days of storage at room temperature (24-32°C) that constituted mainly the physiological loss in weight (PLW). Spoilage started after 5 days of storage (10.5 %) and reached to 28.31 % by 6 days of storage. After 4 days of storage, guava fruits lose weight to the extent of 6 per cent and the spoilage starts after 5 days. Hence, care should be taken to dispose of the fruits within five days of harvest

Extracellular vesicles produced by the human commensal gut bacterium Bacteroides thetaiotaomicron affect host immune pathways in a cell-type specific manner that are altered in inflammatory bowel disease

The gastrointestinal (GI) tract harbours a complex microbial community, which contributes to its homeostasis. A disrupted microbiome can cause GI-related diseases, including inflammatory bowel disease (IBD), therefore identifying host-microbe interactions is crucial for better understanding gut health. Bacterial extracellular vesicles (BEVs), released into the gut lumen, can cross the mucus layer and access underlying immune cells. To study BEV-host interactions, we examined the influence of BEVs generated by the gut commensal bacterium, Bacteroides thetaiotaomicron, on host immune cells. Single-cell RNA sequencing data and host-microbe protein-protein interaction networks were used to predict the effect of BEVs on dendritic cells, macrophages and monocytes focusing on the Toll-like receptor (TLR) pathway. We identified biological processes affected in each immune cell type and cell-type specific processes including myeloid cell differentiation. TLR pathway analysis highlighted that BEV targets differ among cells and between the same cells in healthy versus disease (ulcerative colitis) conditions. The in silico findings were validated in BEV-monocyte co-cultures demonstrating the requirement for TLR4 and Toll-interleukin-1 receptor domain-containing adaptor protein (TIRAP) in BEV-elicited NF-kB activation. This study demonstrates that both cell-type and health status influence BEV-host communication. The results and the pipeline could facilitate BEV-based therapies for the treatment of IBD

Jahn-Teller polarons and their superconductivity in a molecular conductor

We present a theoretical study of a possibility of superconductivity in a three dimensional molecular conductor in which the interaction between electrons in doubly degenerate molecular orbitals and an {\em intra}molecular vibration mode is large enough to lead to the formation of $E\otimes \beta$ Jahn-Teller small polarons. We argue that the effective polaron-polaron interaction can be attractive for material parameters realizable in molecular conductors. This interaction is the source of superconductivity in our model. On analyzing superconducting instability in the weak and strong coupling regimes of this attractive interaction, we find that superconducting transition temperatures up to 100 K are achievable in molecular conductors within this mechanism. We also find, for two particles per molecular site, a novel Mott insulating state in which a polaron singlet occupies one of the doubly degenerate orbitals on each site. Relevance of this study in the search for new molecular superconductors is pointed out.Comment: Submitted to Phys. Rev.

Experimental evidence for the formation of stripe phases in Si/SiGe

We observe pronounced transport anisotropies in magneto-transport experiments performed in the two-dimensional electron system of a Si/SiGe heterostructure. They occur when an in-plane field is used to tune two Landau levels with opposite spin to energetic coincidence. The observed anisotropies disappear drastically for temperatures above 1 K. We propose that our experimental findings may be caused by the formation of a unidirectional stripe phase oriented perpendicular to the in-plane field.Comment: 4 pages, 3 figure

Thermodynamics of Born-Infeld Black Holes

We discuss the horizon structure for Born-Infeld black holes, in the context of Einstein-Born-Infeld gravity. We show that the entropy function formalism agrees with a direct calculation of the entropy. With the entropy function formalism we also obtain the entropy when an axion-dilaton system as well as gravitational derivative corrections are included.Comment: Latex, 13 pages, 1 figure, added reference

Spatiotemporal network coding of physiological mossy fiber inputs by the cerebellar granular layer

The granular layer, which mainly consists of granule and Golgi cells, is the first stage of the cerebellar cortex and processes spatiotemporal information transmitted by mossy fiber inputs with a wide variety of firing patterns. To study its dynamics at multiple time scales in response to inputs approximating real spatiotemporal patterns, we constructed a large-scale 3D network model of the granular layer. Patterned mossy fiber activity induces rhythmic Golgi cell activity that is synchronized by shared parallel fiber input and by gap junctions. This leads to long distance synchrony of Golgi cells along the transverse axis, powerfully regulating granule cell firing by imposing inhibition during a specific time window. The essential network mechanisms, including tunable Golgi cell oscillations, on-beam inhibition and NMDA receptors causing first winner keeps winning of granule cells, illustrate how fundamental properties of the granule layer operate in tandem to produce (1) well timed and spatially bound output, (2) a wide dynamic range of granule cell firing and (3) transient and coherent gating oscillations. These results substantially enrich our understanding of granule cell layer processing, which seems to promote spatial group selection of granule cell activity as a function of timing of mossy fiber input