Anomalous Thermoelectric power of over-doped Bi2Sr2CaCu2O8 superconductor

Temperature dependence of thermoelectric power S(T) of three differently processed Bi2Sr2CaCu2O8 (Bi2212) samples, viz. as-processed melt quenched (Bi2212-MQ), 6000C N2-annealed (Bi2212-N2) and 6000C O2-annealed (Bi2212-O2) is reported here. All the samples possess single-phase character and their superconducting transition temperatures (TcR=0) are 85 K, 90 K and 72 K respectively for Bi2212-MQ, Bi2212-N2 and Bi2212-O2. While Bi2212-MQ and Bi2212-N2 samples are in near optimum doping regime, Bi2212-O2 is an over-doped sample. TcS=0 values obtained through S(T) data are also in line with those deduced from the temperature dependence of resistance and DC magnetization. Interestingly, S(T) behaviour of the optimally-doped Bi2212-MQ and Bi2212-N2 samples is seen to be positive in whole temperature range, it is found negative for the over-doped Bi2212-O2 sample above TcS=0. These results have been seen in the light of the recent band structure calculations and the ensuing split Fermi surface as determined by angle-resolved photoelectron spectroscopy (ARPES).Comment: 11 Pages Text + Figs: comments welcome ([email protected]

Analysis of MAGSAT data of the Indian region

Progress in the development of software for reading MAGSAT data tapes and for the reduction of anomaly data, and in the preparation of data for magnetic anomaly maps is reported

Radio continuum properties of young planetary nebulae

We have selected a small sample of post-AGB stars in transition towards the planetary nebula and present new Very Large Array multi-frequency high-angular resolution radio observations of them. The multi-frequency data are used to create and model the targets' radio continuum spectra, proving that these stars started their evolution as very young planetary nebulae. In the optically thin range, the slopes are compatible with the expected spectral index (-0.1). Two targets (IRAS 18062+2410 and 17423-1755) seem to be optically thick even at high frequency, as observed in a handful of other post-AGB stars in the literature, while a third one (IRAS 20462+3416) shows a possible contribution from cold dust. In IRAS 18062+2410, where we have three observations spanning a period of four years, we detect an increase in its flux density, similar to that observed in CRL 618. High-angular resolution imaging shows bipolar structures that may be due to circumstellar tori, although a different hypothesis (i.e., jets) could also explain the observations. Further observations and monitoring of these sources will enable us to test the current evolutionary models of planetary nebulae.Comment: 8 pages, 3 figures, accepted for publication in MNRA

Muon-spin spectroscopy of the organometallic spin-1/2 kagome-lattice compound Cu(1,3-benzenedicarboxylate)

Using muon-spin resonance, we examine the organometallic hybrid compound Cu(1,3-benzenedicarboxylate) [Cu(1,3-bdc)], which has structurally perfect spin-1/2 copper kagome planes separated by pure organic linkers. This compound has antiferromagnetic interactions with Curie-Weiss temperature of −33 K. We found slowing down of spin fluctuations starting at T=1.8 K and that the state at T→0 is quasistatic with no long-range order and extremely slow spin fluctuations at a rate of 3.6 μs[superscript −1]. This indicates that Cu(1,3-bdc) behaves as expected from a kagome magnet and could serve as a model kagome compound.European Commission (under the Sixth Framework Program through the Key Action: Strengthening the European Research Area, Research Infrastructures, Contract No. RII3-CT-2004-506008)European Science FoundationIsrael U.S.A. Binational Science Foundatio

Functional deficits as a result of brachial plexus injury in anterior shoulder dislocation

The incidence of brachial plexus injuries in anterior shoulder dislocation remains relatively uncommon. A retrospective study was conducted to observe the natural neurological recovery of patients following these injuries over a 2-year period. Muscle power according to the Medical Research Council scale and sensation were measured from presentation to discharge. In 28 patients, the power grade of proximal muscles supplied by nine injured nerves failed to improve over a median follow-up of 5 months. There was no statistically significant improvement in sensation over a median follow-up of 6 months. Poorer recovery in muscle power score was related to advancing age, whereby every decade increased the risk by approximately 30%. Anterior shoulder dislocation with a plexus injury carries a risk of permanent nerve injury. Patients should be referred for specialist nerve assessment leading to rehabilitation and timely early nerve reconstruction, if indicated

A Search for Propylene Oxide and Glycine in Sagittarius B2 (LMH) and Orion

We have used the Mopra Telescope to search for glycine and the simple chiral molecule propylene oxide in the Sgr B2 (LMH) and Orion KL, in the 3-mm band. We have not detected either species, but have been able to put sensitive upper limits on the abundances of both molecules. The 3-sigma upper limits derived for glycine conformer I are 3.7 x 10^{14} cm^{-2} in both Orion-KL and Sgr B2 (LMH), comparable to the reported detections of conformer I by Kuan et al. However, as our values are 3-sigma upper limits rather than detections we conclude that this weighs against confirming the detection of Kuan et al. We find upper limits for the glycine II column density of 7.7 x 10^{12} cm^{-2} in both Orion-KL and Sgr B2 (LMH), in agreement with the results of Combes et al. The results presented here show that glycine conformer II is not present in the extended gas at the levels detected by Kuan et al. for conformer I. Our ATCA results (Jones et al.) have ruled out the detection of glycine (both conformers I and II) in the compact hot core of the LMH at the levels reported, so we conclude that it is unlikely that Kuan et al. have detected glycine in either Sgr B2 or Orion-KL. We find upper limits for propylene oxide abundance of 3.0 x 10^{14} cm^{-2} in Orion-KL and 6.7 x 10^{14} cm^{-2} in Sgr B2 (LMH). We have detected fourteen features in Sgr B2 and four features in Orion-KL which have not previously been reported in the ISM, but have not be able to plausibly assign these transitions to any carrier.Comment: 12 pages, 3 figures. Accepted by MNRAS 12th January 200

New Longitudinal Waves in Electron-Positron-Ion Quantum Plasmas

A general quantum dispersion equation for electron-positron(hole)-ion quantum plasmas is derived and studied for some interesting cases. In an electron-positron degenerate Fermi gas, with or without the Madelung term, a new type of zero sound waves are found. Whereas in an electron-hole plasmas a new longitudinal quantum waves are revealed, which have no analogies in quantum electron-ion plasmas. The excitation of these quantum waves by a low-density monoenergetic straight electron beam is examined. Furthermore, the KdV equation for novel quantum waves is derived and the contribution of the Madelung term in the formation of the KdV solitons is discussed

EFFECTS OF WEARING HEADSCARVES ON CERVICAL SPINE MOBILITY

Background: Cervical spine provides three-dimensional movements of the head on the body while keeping the horizontality of visual gaze. Thus, cervical range of motion (ROM) is an important assessment that is commonly used in clinical practice. The headscarf is commonly used attire by females in Islamic cultures. The study aimed to investigate the effect of wearing headscarves on cervical ROM in females who wear headscarves compared with females who don’t wear headscarves. Methods: A cross-sectional study was conducted on fifty-two females with mean age 28.1±3.1 years were divided into two groups: Headscarf group (n=26) and no-scarf group (n=26). Cervical Range of Motion Device was used to measure cervical spine range of motion in a seated position for flexion, extension, right lateral flexion, left lateral flexion, right rotation and left the rotation. Results: The headscarf group reported a significant limitation in cervical ROM in all six directions. Moreover, females in the headscarf group who wore the headscarf for more or equal to 6 hours had significantly less left rotation compared to those who wear it for less than 6 hours (71.3±2.1 vs. 64.5±2.1, η2=2.2; p=0.045). No significant differences in mean ROM by age at onset of wearing a headscarf (≤12 years vs. > 12 years) or a number of years worn (≤15 years vs. > 15 years) were detected (p>0.05). Conclusion: Wearing the headscarf may influence cervical ROM. Also, six hours or more of daily wear may result in further decline of cervical ROM

Effect of additive concentration during copper deposition using EnFACE electrolyte

Copper deposition from solutions using high concentration of acid, metal ions and polyethylene glycol (PEG), and bis-(3-sulphopropyl) disulphide (SPS) and chloride ions (Cl-) is well known. A recent maskless micropatterning technology, which has the potential to replace the traditional photolithographic process, called EnFACE, proposed using an acid-free, low metal ion solution which is in direct contrast to those used in standard plating technology. In this work copper has been deposited using both standard electroplating solutions and those used in the EnFACE process. In the standard electrolyte 0.63 M CuSO4 and 2.04 M H2SO4 has been used, along with Gleam additives supplied by Dow Chemicals. For the Enface electrolyte, copper deposition has been carried out without any acid, and with different concentrations of additives between 17%-200% of those recommended by suppliers. 25 μm of metal has been plated on stainless steel coupons as suggested by ASTM, peeled off and subjected to ductility and resistance measurements. Scanning electron microscopy and electron back scatter diffraction have been carried out to determine the deposit morphology. It was found that copper deposits obtained from acid-free solutions containing low concentration of metal ion and additives produced copper deposits with properties which are comparable to those obtained from standard electrolytes. The optimum additive concentration for the EnFACE electrolyte was 50% of the supplier recommended value

Molecular line mapping of the giant molecular cloud associated with RCW 106 - II. Column density and dynamical state of the clumps

We present a fully sampled C^{18}O (1-0) map towards the southern giant molecular cloud (GMC) associated with the HII region RCW 106, and use it in combination with previous ^{13}CO (1-0) mapping to estimate the gas column density as a function of position and velocity. We find localized regions of significant ^{13}CO optical depth in the northern part of the cloud, with several of the high-opacity clouds in this region likely associated with a limb-brightened shell around the HII region G333.6-0.2. Optical depth corrections broaden the distribution of column densities in the cloud, yielding a log-normal distribution as predicted by simulations of turbulence. Decomposing the ^{13}CO and C^{18}O data cubes into clumps, we find relatively weak correlations between size and linewidth, and a more sensitive dependence of luminosity on size than would be predicted by a constant average column density. The clump mass spectrum has a slope near -1.7, consistent with previous studies. The most massive clumps appear to have gravitational binding energies well in excess of virial equilibrium; we discuss possible explanations, which include magnetic support and neglect of time-varying surface terms in the virial theorem. Unlike molecular clouds as a whole, the clumps within the RCW 106 GMC, while elongated, appear to show random orientations with respect to the Galactic plane.Comment: 17 pages, to appear in MNRA