Superconductivity in doped FeTe1-xSx (x= 0.00 to 0.25) single crystals

We report self flux growth and characterization of FeTe1-xSx (x= 0.00 to 0.25) single crystal series. Surface X-ray diffraction (XRD) exhibited crystalline nature with growth in (00l) plane. Micro-structural (electron microscopy) images of representative crystals showed the slab-like morphology and near stoichiometric composition. Powder XRD analysis (Rietveld) of single crystals exhibited tetragonal structure with P4/nmm space group and decreasing a and c lattice parameters with increase in x. Electrical resistivity measurements (R-T) showed superconductivity with Tconset at 9.5K and 8.5K for x =0.10 and x =0.25 respectively. The un-doped crystal exhibited known step like anomaly at around 70K. Upper critical field Hc2(0), as calculated from magneto transport for x =0.25 crystal is around 60Tesla and 45Tesla in H//ab and H//c directions. Thermal activation energy [U0(H)] calculated for x =0.10 and 0.25 crystals followed weak power law, indicating single vortex pinning at low fields. Mossbauer spectra for FeTe1-xSx crystals at 300K and 5K are compared with non superconducting FeTe. Both quadrupole splitting (QS) and isomer shift (IS) for S doped crystals were found to decrease. Also at 5K the hyperfine field for x =0.10 superconducting crystal is decreased substantially from 10.6Tesla (FeTe) to 7.2Tesla. For x =0.25 crystal, though small quantity of un-reacted Fe is visible at room temperature, but unlike x =0.10, the low temperature (5K) ordered FeTe hyperfine field is nearly zero.Comment: 20 Pages Text + Figs: Accepted Mat. Res. Exp, Mat. Rex. Exp. (2018

The helping hand, the lazy hand, or the grabbing hand? Central vs. local government shareholders in publicly listed firms in China

We analyze related party transactions between Chinese publicly listed firms and their stateowned enterprise (SOEs) shareholders to examine whether companies benefit from the presence of government shareholders and politically connected directors appointed by the government. We find that related party transactions between firms and their government shareholders seem to result in expropriation of the minority shareholders in firms controlled by local government SOEs or with a large proportion of local government affiliated directors on their board, and in provinces where local government bureaucrats are less likely to be prosecuted for misappropriation of state funds. On the other hand, firms controlled by the central government (or with a large proportion of central government affiliated directors) are benefited in their related party transactions with their central government SOEs.Law and economics, Government ownership, China, State-Owned Enterprises (SOE), Related party transactions, Political connections

A New VLSI Architecture of Parallel Multiplier–Accumulator Based on Radix-2 Modified Booth Algorithm

In this paper, we proposed a new architecture of multiplier-and-accumulator (MAC) for high-speed arithmetic.By combining multiplication with accumulation and devising a hybrid type of carry save adder (CSA), the performance was improved. Since the accumulator that has the largest delay in MAC was merged into CSA, the overall performance was elevated. The proposed CSA tree uses 1’s-complement-based radix-2 modified Booth’s algorithm (MBA) and has the modified array for the sign extension in order to increase the bit density of the operands. The CSA propagates the carries to the least significant bits of the partial products and generates the least significant bits in advance to decrease the number of the input bits of the final adder. Also, the proposed MAC accumulates the intermediate results in the type of sum and carry bits instead of the output of the final adder, which made it possible to optimize the pipeline scheme to improve the performance. The proposed architecture was synthesized with 250, 180 and 130 m, and 90 nm standard CMOS library. Based on the theoretical and experimental estimation, we analyzed the results such as the amount of hardware resources, delay, and pipelining scheme. We used Sakurai’s alpha power law for the delay modeling. The proposed MAC showed the superior properties to the standard design in many ways and performance twice as much as the previous research in the similar clock frequency. We expect that the proposed MAC can be adapted to various fields requiring high performance such as the signal processing areas

Regulation of worker activity in the primitively eusocial wasp Ropalidia cyathiformis

Ropalidia marginata, traditionally regarded as a primitively eusocial wasp species appears to have acquired some features reminiscent of highly eusocial species. Queens are behaviorally passive individuals, yet maintain complete reproductive monopoly and probably use pheromones to achieve this. Regulation of worker foraging is achieved by the workers themselves in a decentralized, self-organized manner. If there are other species in the genus Ropalidia that do not show such relatively 'advanced' features, this genus can provide an attractive model system to investigate the evolutionary transition from the primitively eusocial to the highly eusocial state. Here, we therefore investigate the congeneric Ropalidia cyathiformis and demonstrate that in contrast to R. marginata, it appears to be a typical primitively eusocial species. As expected therefore, and in striking contrast with R. marginata, R. cyathiformis queens are the most, or among the most, dominant, active and interactive individuals and their behavior is consistent with the possibility that they suppress worker reproduction and regulate worker foraging in a relatively centralized manner. Upon removal of the queen, a potential queen with levels of aggression even higher than that of the queen, becomes apparent immediately. Such a potential queen appears to take over inhibition of worker reproduction and regulation of worker foraging by mechanisms similar to that used by the queen so that, there is no disruption in foraging and brood care. We suggest that comparative studies of R. marginata and R. cyathiformis provide a unique opportunity to investigate the evolutionary transition from the primitively eusocial to the highly eusocial state

Bacteriophage burst size during multiple infections

A significant positive correlation was observed between multiplicity of infection and burst size of mycobacteriophage 13. During multiple infections, the average contribution of each infecting phage to the burst size was inversely correlated with multiplicity of infection even when bacterial resources were not limiting. We conclude that the efficiency of phage-coded functions rather than the extent of bacterial resources determines the burst size

Growth of Mycobacterium smegmatis in minimal and complete media

The growth patterns of Mycobacterium smegmat is SN2 in a minimal medium and in nutrient broth have been compared. The growth was monitored by absorbancy (Klett readings), colony forming units, wet weight and content of DNA, RNA and protein. During the early part of the growth cycle, the bacteria had higher wet weight and macromolecular content in nutrient broth than in minimal media. During the latter half of the growth cycle however, biosynthesis stopped much earlier in nutrient broth and the bacteria had a much lower content of macromolecules than in the minimal medium. In both the media, a general pattern of completing biosynthesis rapidly in the initial phase and a certain amount of cell division at a later time involving the distribution of preformed macromolecules was seen. The possible adaptive significance of this observation has been discussed

Docile sitters and active fighters in paper wasps: a tale of two queens

Ropalidia marginata and Ropalidia cyathiformis are sympatric, primitively eusocial paper wasps widely distributed in peninsular India. We compare the two species, especially their queens, in an attempt to begin to understand the role of the power of queens over their workers, in social organisation and evolution. Queens of R. marginata have lower levels of activity, rates of interactions and dominance behaviour, compared with queens of R. cyathiformis. For the same variables, R. marginata queens are either indistinguishable from or have lower values than their workers, while R. cyathiformis queens have higher values than their workers. R. marginata queens never occupy the top rank while R. cyathiformis queens are always at the top of the behavioural dominance hierarchies of their colonies. R. marginata queens thus do not appear to use dominance behaviour to suppress reproduction by their workers, while R. cyathiformis queens appear to do so. These different mechanisms used by the two queens to regulate worker reproduction give them different powers over their workers, because R. marginata queens are completely successful in suppressing reproduction by their nestmates while in R. cyathiformis colonies, other individuals also sometimes lay eggs. There is also some evidence that the different powers of the queens result in different mechanisms of regulation of worker foraging in the two species-decentralised, self-regulation in R. marginata and relatively more centralised regulation by the queen in R. cyathiformis. Thus we show here, perhaps for the first time, that the power of the queens over their workers can have important consequences for social organisation and evolution

Bilarge neutrino mixing from supersymmetry with high-scale nonrenormalizable interactions

We suggest a supersymmetric (SUSY) explanation of neutrino masses and mixing, where nonrenormalizable interactions in the hidden sector generate lepton number violating Majorana mass terms for both right-chiral sneutrinos and neutrinos. It is found necessary to start with a superpotential including an array of gauge singlet chiral superfields. This leads to nondiagonal $\Delta L = 2$ mass terms and almost diagonal SUSY breaking $A$-terms. As a result, the observed pattern of bilarge mixing can be naturally explained by the simultaneous existence of the seesaw mechanism and radiatively induced masses. Allowed ranges of parameters in the gauge singlet sector are delineated, corresponding to each of the cases of normal hierarchy, inverted hierarchy and degenerate neutrinos.Comment: 19 pages, 5 figures. Minor modifications are made in the title and the text, some new references are added. To appear in this form in Physical Review