Very recent report 1 on observation of superconductivity in Bi 4 O 4 S 3 could potentially reignite the search for superconductivity in a broad range of layered sulfides. We report here synthesis of Bi 4 O 4 S 3 at 500 0 C by vacuum encapsulation technique and its basic characterizations. Bi 4 O 4 S 3 is contaminated by small amounts of Bi 2 S 3 and Bi impurities. The majority phase is tetragonal I4/mmm space group with lattice parameters a = 3.9697(2)Å, c = 41.3520(1)Å. Both AC and DC magnetization measurements confirmed that Bi 4 O 4 S 3 is a bulk superconductor with superconducting transition temperature (T c ) of 4.4K. Isothermal magnetization (MH) measurements indicated closed loops with clear signatures of flux pinning and irreversible behavior. The lower critical field (H c1 ) at 2K, of the new superconductor is found to be ~15 Oe. The magneto-transport R(T, H) measurements showed a resistive broadening and decrease in T c (ρ=0) to lower temperatures with increasing magnetic field. The extrapolated upper critical field H c2 (0) is ~ 31kOe with a corresponding Ginzburg-Landau coherence length of ~100Å . In the normal state the ρ ~ T 2 is not indicated. Hall resistivity data show non-linear magnetic field dependence. Our magnetization and electrical transport measurements substantiate the appearance of bulk superconductivity in as synthesized Bi 4 O 4 S 3 . On the other hand same temperature heat treated Bi is not superconducting, thus excluding possibility of impurity driven superconductivity in the newly discovered Bi 4 O 4 S 3 superconductor.

Strontium intercalation between van der Waals bonded layers of topological insulator Bi 2 Se 3 is found to induce superconductivity with a maximum T c of 2.9 K. Transport measurement on single crystal of optimally doped sample Sr 0.1 Bi 2 Se 3 shows weak anisotropy ( 1.5) and upper critical field H c2 (0) Superconductors derived from topological insulating phases of quantum matter are amongst the most profound developments of recent past.

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Background and ObjectivesHigh maternity-related health care spending is often cited as an important barrier in utilizing quality health care during pregnancy and childbirth. This study has two objectives: (i) to measure the levels of expenditure on total maternity care in disaggregated components such as ANCs, PNCs, and Natal care expenditure; (ii) to quantify the extent of catastrophic maternity expenditure (CME) incurred by households and identify the factors responsible for it.Methods and FindingsData from the 71st round of the National Sample Survey (2014) was used to estimate maternity expenditure and its predictors. CME was measured as a share of consumption expenditure by different cut-offs. The two-part model was used to identify the factors associated with maternity spending and CME. The findings show that household spending on maternity care (US$ 149 in constant price) is much higher than previous estimates (US$ 50 in constant price). A significant proportion of households in India (51%) are incurring CME. Along with economic and educational status, type of health care and place of residence emerged as significant factors in explaining CME.ConclusionFindings from this study assume importance in the context of an emerging demand for higher maternity entitlements and government spending on public health care in India. To reduce CME, India needs to improve the availability and accessibility of better-quality public health services and increase maternity entitlements in line with maternity expenditure identified in this study.

We report on the superconducting gap and pairing symmetry in layered superconductor Bi 4 O 4 S 3 . The measurement of temperature dependence of magnetic penetration depth was carried out using tunnel diode oscillator technique. It is observed that Bi 4 O 4 S 3 is a conventional s-wave type superconductor with fully developed gap. The zero-temperature value of the superconducting energy gap Δ 0 was found to be 1.54 meV, corresponding to the ratio 2Δ 0 /k B T c =7.2 which is much higher than the BCS value of 3.53. In the superconducting range, superfluid density is very well described by single gap s-wave model.