Exploring metastability via the third harmonic measurements in single crystals of 2H2H-NbSe2NbSe_2 showing anomalous Peak effect

We explore the metastability effects across the order-disorder transition pertaining to the peak effect phenomenonon in critical current density ($J_c$) via the first and the third harmonic ac susceptibility measurements in the weakly pinned single crystals of $2H$-$NbSe_2$. An analysis of our data suggests that an imprint of the limiting (spinodal) temperature above which $J_c$ is path independent can be conveniently located in the third harmonic data ($\chi_{3\omega}^{\prime}$).Comment: Accepted for publication in Phys. Rev.

Feeding behaviour and pugmark analysis of elephants in Sarguja, Chhattisgarh

The pugmark analysis of the elephants offers basic information to track the wild elephant migratory route, identification and census. For its study, four blocks viz, Sitapur, Lundra, Batouli (Sarguja district) and Farsabahar (Jashpur district) of northern Chhattisgarh were selected because these blocks are commonly visited by elephants and a major path route of movement of heard in inter/intra state. The most commonly consumed species belongs to family poaceae (22.58%) followed by fabaceae (19.35%) but their diet was mainly dependent on availability of seasonal food round the year and on their migration. Elephants extensively fed on Artocarpus heterophyllus, Syzygium cumini, Acacia nilotica, A. catechu, Dalbergia sissoo, Zizyphus mauritiana, Aegle marmelos and Ficus species, besides these elephants also utilized various grasses and shrubs as their food, which mainly included Dendrocalamus strictus, Cynodon dactylon etc. Elephants sometimes spent long time to feed on some particular plant species like D. strictus and Ficus species. Crop raiding, which was sporadic during the rainy season, gradually increased with more area being cultivated with the onset of monsoon. Analysis of pugmark revealed that the circumference varied from 63.80 cm to 172.70 cm whereas length x width varied from 22x20 cm to 60x55 cm, which reflects a substantial variation/differentiation of individual in heard in respect of their age, sex, size etcTherefore, management implications are needed to conserve the corridors for their long term survival and reduction of HEC. The study will be helpful to provide key information and facilitate better understating of the scenario to the forest department, policy maker and conservationist to plan, manage and improve the habitat towards the restoration and afforestation of suitable palatable species preferred by elephants of northern corridors of Chhattisgarh

Socio-economic status of human-elephant conflict: Its assessment and solutions

The study was made to examine the effect of human-elephant conflict (HEC) on socio-economic vulnerability in corridors of northern Chhattisgarh. Incidents relating to conflicts were observed and analyzed to understand the socio-economic status of the people, their attitudes towards elephant, the way people and elephants were affected along with different aspects of conflicts. The records whatsoever available on HEC of forest department were also took into consideration during analysis. It was found that majority of respondents involved in farming besides other sources like livestock (63.0%), NTFPs collection (42.50%) etc. Paddy (57.50%) and sugarcane (40.0%) constitute major crops which likely favours the incidence of HEC in the region. Nearly 112 houses and 939.02 acre of crops were damaged along with 06 human deaths. It was found that 46% of the respondents respected the animal as a religious figure while 30% fear them and most of the respondents (77.50%) were in favour of compensation. This necessitated a detailed assessment of habitat suitability and dispersal corridor for elephants in the area. Therefore, an attempt has been made to present various aspects of HEC along with management implications

Critical points in the Bragg glass phase of a weakly pinned crystal of Ca3_3Rh4_4Sn13_{13}

New experimental data are presented on the scan rate dependence of the magnetization hysteresis width $\Delta M(H)$ ($\propto$ critical current density $J_c(H)$) in isothermal $M-H$ scans in a weakly pinned single crystal of Ca$_3$Rh$_4$Sn$_{13}$, which displays second magnetization peak (SMP) anomaly as distinct from the peak effect (PE). We observe an interesting modulation in the field dependence of a parameter which purports to measure the dynamical annealing of the disordered bundles of vortices injected through the sample edges towards the destined equilibrium vortex state at a given $H$. These data, in conjunction with the earlier observations made while studying the thermomagnetic history dependence in $J_c(H)$ in the tracing of the minor hysteresis loops, imply that the partially disordered state heals towards the more ordered state between the peak field of the SMP anomaly and the onset field of the PE. The vortex phase diagram in the given crystal of Ca$_3$Rh$_4$Sn$_{13}$ has been updated in the context of the notion of the phase coexistence of the ordered and disordered regions between the onset field of the SMP anomaly and the spinodal line located just prior to the irreversibility line. A multi-critical point and a critical point in the ($H,T$) region of the Bragg glass phase have been marked in this phase diagram and the observed behaviour is discussed in the light of recent data on multi-critical point in the vortex phase diagram in a single crystal of Nb.Comment: To appear in Current trends in Vortex State Studies - Pramana J. Physic

Record of complete albinism in marine catfish, Osteogeneiosus militaris (Linnaeus, 1758), landed at Mumbai

Albinism is due to one of several gene mutations that affect the normal pigmentation. There are various degrees of albinism. True albino or amelanistic animals lack melanin and are white with unpigmented pink eyes

Flux jumps, Second Magnetization Peak anomaly and the Peak Effect phenomenon in single crystals of YNi2B2CYNi_2B_2C and LuNi2B2CLuNi_2B_2C

We present magnetization measurements in single crystals of the tetragonal $YNi_2B_2C$ compound, which exhibit the phenomenon of peak effect as well as the second magnetization peak anomaly for H $>$ 0.5T (H $||$ c). At the lower field (50mT $<$ H $<$ 200mT), we have observed the presence of flux jumps, which seem to relate to a structural change in the local symmetry of the flux line lattice (a first order re-orientation transition across a local field in some parts of the sample, in the range of 100mT to 150mT). These flux jumps are also observed in a single crystal of $LuNi_2B_2C$ for H $||$ c in the field region from 2 mT to 25 mT, which are compatible with the occurrence of a re-orientation transition at a lower field in a cleaner crystal of this compound, as compared to those of $YNi_2B_2C$. Vortex phase diagrams drawn for H $||$ c in $LuNi_2B_2C$ and $YNi_2B_2C$ show that the ordered elastic glass phase spans a larger part of (H, T) space in the former as compared to latter, thereby, reaffirming the difference in the relative purity of the two samples.Comment: 11 pages, 14 figure

Magnetization hysteresis and time decay measurements in FeSe0.50_{0.50}Te0.50_{0.50} : Evidence for fluctuation in mean free path induced pinning

We present results of magnetic measurements relating to vortex phase diagram in a single crystal of FeSe$_{0.5}$Te$_{0.5}$ which displays second magnetization peak anomaly for $H \parallel c$. The possible role of the crystalline anisotropy on vortex pinning is explored via magnetic torque magnetometry. We present evidence in favor of pinning related to spatial variations of the charge carrier mean free path leading to small bundle vortex pinning by randomly distributed (weak) pinning centers for both $H \parallel c$ and $H \perp c$. This is further corroborated using magnetization data for $H \parallel c$ in a single crystal of FeSe$_{0.35}$Te$_{0.65}$. Dynamical response across second magnetization peak (SMP) anomaly in FeSe$_{0.5}$Te$_{0.5}$ has been compared with that across the well researched phenomenon of peak effect (PE) in a single crystal of CeRu$_2$.Comment: 11 figures, provided additional data in another sample, added Fig.

On the optical properties of Ag^{+15} ion-beam irradiated TiO_{2} and SnO_{2} thin films

The effects of 200-MeV Ag^{+15} ion irradiation on the optical properties of TiO_{2} and SnO_{2} thin films prepared by using the RF magnetron sputtering technique were investigated. These films were characterized by using UV-vis spectroscopy, and with increasing irradiation fluence, the transmittance for the TiO_{2} films was observed to increase systematically while that for SnO_{2} was observed to decrease. Absorption spectra of the irradiated samples showed minor changes in the indirect bandgap from 3.44 to 3.59 eV with increasing irradiation fluence for TiO_{2} while significant changes in the direct bandgap from 3.92 to 3.6 eV were observed for SnO_{2}. The observed modifications in the optical properties of both the TiO_{2} and the SnO_{2} systems with irradiation can be attributed to controlled structural disorder/defects in the system.Comment: 6 pages, ICAMD-201

Unusual landing of Alepes djeddaba (Forskal) and Megalaspis cordyla (Linnaeus) by purse seiners at New Ferry Wharf Mumbai.

Carangids include 25 genera and 140 species. They are abundant in shallow water up to 60 meter depth along both coasts supporting fishery almost round the year.The fishery is constituted mainly by Megalaspis cordyla, Decapterus russelli,Alepes djeddaba, Selar crumenopthalamus,Carnax spp,Caragoides spp, and scomberoides spp. in Maharastra