Metastability and uniqueness of vortex states at depinning

We present results from numerical simulations of transport of vortices in the zero-field cooled (ZFC) and the field-cooled (FC) state of a type-II superconductor. In the absence of an applied current $I$, we find that the FC state has a lower defect density than the ZFC state, and is stable against thermal cycling. On the other hand, by cycling $I$, surprisingly we find that the ZFC state is the stable state. The FC state is metastable as manifested by increasing $I$ to the depinning current $I_{c}$, in which case the FC state evolves into the ZFC state. We also find that all configurations acquire a unique defect density at the depinning transition independent of the history of the initial states.Comment: 4 pages, 4 figures. Problem of page size correcte

Trials for neurodegenerative diseases:time to innovate

The remarkable progress in our understanding of the mechanisms underlying neurodegenerative diseases heralds an era when neurologists would be at the vanguard of regenerative medicine, instead of chroniclers of decline. To capitalise on these advances that are identifying ever more therapeutic candidates, whether repurposed or entirely new, there is an urgent need for refined methods to test these putative medicines in clinical trials. Our field has the opportunity to learn from innovations in trial design, particularly those pioneered in oncology

Peak Effect in Superconductors: Absence of Phase Transition and Possibility of Jamming in Vortex Matter

The magnetic field $B$ dependence of the critical current $I_c$ for the vortex phase of a disordered superconductor is studied numerically at zero temperature. The $I_{c}(B)$ increases rapidly near the upper critical field $B_{c2}$ similar to the peak effect (PE) phenomenon observed in many superconductors. The real space configuration across the PE changes continuously from a partially ordered domain (polycrystalline) state into an amorphous state. The topological defect density $n_{d}(B)\sim e^{\alpha B^{k}}$ with $k>1$ for $B\geq 0.4B_{c2}$. There is no evidence of a phase transition in the vicinity of the PE suggesting that an order-disorder transition is not essential for the occurrence of the PE phenomenon. An alternative view is presented wherein the vortex system with high dislocation density undergoes jamming at the onset of the PE.Comment: 8 pages and 5 figure

Status of woolly aphid Ceratovacuna lanigera and establishment of the parasitoid Encarsia flavoscutellum in sugarcane germplasm

Woolly aphid Ceratovacuna lanigera Zehntner (Hemiptera: Aphididae), a native of north-eastern India, appeared in the world sugarcane germplasm maintained at the ICAR-Sugarcane Breeding Institute Research Center (ICAR-SBIRC), Kannur, Kerala State, India, first in 2004. The aphid colonized Indian hybrids and accessions of Saccharum officinarum, Saccharum sinense, Saccharum robustum and Saccharum barberi in the first year of occurrence and every year thereafter. Early detection and spot application of insecticide were adopted to manage the aphid and protect germplasm. Soap solution was applied in the later years to conserve the predators Dipha aphidivora Metrics (Lepidoptera:Pyralidae) and Micromus sp. (Neuroptera: Hemerobiidae) that occurred intermittently. The parasitoid Encarsia flavoscutellum Zehntner (Hymenoptera: Aphelenidae) maintained at Coimbatore, Tamil Nadu State, India, was released in the germplasm thrice, i.e. in January 2009, November 2014 and June 2015. Post-release, E. flavoscutellum parasitism was detected first during April-June 2015 at low levels (2.0- 3.5%). Clear-cut evidence of establishment was witnessed during September-October 2021 when aphids showed a high 27.0% parasitism. Since E. flavoscutellum was found to regulate populations of woolly aphid wherever it established, it is expected to reach similar equilibrium with the aphid in the germplasm, D. aphidivora and Micromus sp. playing a complementary role at high aphid densities. However, continuous monitoring of aphid and natural enemies, and use of safer emergency control measures would go a long way in maintaining the germplasm free from woolly aphid