Thermal conductivity of graphene in Corbino membrane geometry

Local laser excitation and temperature readout from the intensity ratio of Stokes to anti-Stokes Raman scattering signals are employed to study the thermal properties of a large graphene membrane. The concluded value of the heat conductivity coefficient \kappa ~ 600 W/m \cdot K is smaller than previously reported but still validates the conclusion that graphene is a very good thermal conductor.Comment: 4 pages, 3 figure

On some eel eggs and larvae from the Gulf of Manaar

Though much attention has been devoted to the elucidation of the biology of the eels, the records of their eggs are very rew and, st rangely enough, even the egg of the European eel, Anguilla vulgaris, which was the subject of intensive investigation, remains unknown to Science. The first account of eel eggs was by Raffaele (1888) who studied the early development of five types of unidentified eggs from the Bay of Naples

On the occurrence of sting-ray spines in the jaws and gills of the hammerhead shark Sphyrna zygaena (Linnaeus)

It is well-known that sharks ate voracious feeders and prey upon a wide variety of marine animals such as planktonic crustaceans, crabs, molluscs, fishes, turtles and seals. White examining a specimen of Sphyrnra zygaena (Linnaeus) measuring 3'86 metres in total length (Photo I) which was caught off Tuticorin at 40 fathoms depth by long line on 22nd April, 1971, several spines of sting-rays were found in the ja\vs and gills (Photo 2). The spines occurred in ooth jaws of S. 'Zygaena but most of them were found in the upper jaw and they were observed to have pierced the jaws and gills deeply

Hyperfine interaction and electronic spin fluctuation study on Sr2−x_{2-x}Lax_xFeCoO6_6 (x = 0, 1, 2) by high-resolution back-scattering neutron spectroscopy

The study of hyperfine interaction by high-resolution inelastic neutron scattering is not very well known compared to the other competing techniques viz. NMR, M\"ossbauer, PACS etc. Also the study is limited mostly to magnetically ordered systems. Here we report such study on Sr$_{2-x}$La$_x$FeCoO$_6$ (x = 0, 1, 2) of which first (Sr$_2$FeCoO$_6$ with x = 0) has a canonical spin spin glass, the second (SrLaFeCoO$_6$ with x = 1) has a so-called magnetic glass and the third (La$_2$FeCoO$_6$ with x = 2) has a magnetically ordered ground state. Our present study revealed clear inelastic signal for SrLaFeCoO$_6$, possibly also inelastic signal for Sr$_2$FeCoO$_6$ below the spin freezing temperatures $T_{sf}$ but no inelastic signal at all for for the magnetically ordered La$_2$FeCoO$_6$ in the neutron scattering spectra. The broadened inelastic signals observed suggest hyperfine field distribution in the two disordered magnetic glassy systems and no signal for the third compound suggests no or very small hyperfine field at the Co nucleus due to Co electronic moment. For the two magnetic glassy system apart from the hyperfine signal due only to Co, we also observed electronic spin fluctuations probably from both Fe and Co electronic moments. \end{abstract

Size effect in ion transport through angstrom-scale slits

It has been an ultimate but seemingly distant goal of nanofluidics to controllably fabricate capillaries with dimensions approaching the size of small ions and water molecules. We report ion transport through ultimately narrow slits that are fabricated by effectively removing a single atomic plane from a bulk crystal. The atomically flat angstrom-scale slits exhibit little surface charge, allowing elucidation of the role of steric effects. We find that ions with hydrated diameters larger than the slit size can still permeate through, albeit with reduced mobility. The confinement also leads to a notable asymmetry between anions and cations of the same diameter. Our results provide a platform for studying effects of angstrom-scale confinement, which is important for development of nanofluidics, molecular separation and other nanoscale technologies

The mechanism of nestmate discrimination in the tropical social wasp Ropalidia marginata and its implications for the evolution of sociality

We have demonstrated that females of the primitively eusocial tropical wasp Ropalidia marginata can discriminate nestmates from nonnestmates outside the context of their nests. This was accomplished by recroding all behavioural interactions in a neutral arena and comparing tolerance levels. In order for these wasps to make such a discrimination, however, it was essential that after eclosion both the discriminated and the discriminating animals were exposed to their respective natal nests and nestmates. The results suggest that both recognition labels and templates are acquired by the animals from sources outside their body, perhaps from their nest or nestmates. It is thus unlikely that different genetic lines within a colony can be distinguished. We conclude, therefore, that genetic asymmetries created by haplodiploidy, but often broken down by multiple mating and polygyny, are not restored by preferential altruism towards full rather than half sisters by means of kin recognition. Hence we recommend caution in ascribing the multiple origins of eusociality in the Hymenoptera to haplodiploidy