Peak effect in CeRu2_2:history dependence and supercooling

We present experimental results on single crystal CeRu$_2$ showing that the extent of history dependence of peak-effect depends on the path followed in the space of field (H) and temperature (T). The (H,T) regime over which history effect is observed is larger if the vortex lattice is prepared by lowering T from above T$_C$ in constant H i.e. by field cooling. We compare this history effect with the very recently reported history dependence of peak-effect in detwinned single crystals of YBaCuO, highlighting the similarities and differences. We discuss the possibility of a first order vortex solid-solid transition in CeRu$_2$ within the realm of recent theoretical developments in the field of vortex matter.Comment: 21 pages, 5 figures; submitted to Phys. Rev. B on 9th Feb. 200

Level Splitting in Association with the Multiphoton Bloch-Siegert Shift

We present a unitary equivalent spin-boson Hamiltonian in which terms can be identified which contribute to the Bloch-Siegert shift, and to the level splittings at the anticrossings associated with the Bloch-Siegert resonances. First-order degenerate perturbation theory is used to develop approximate results in the case of moderate coupling for the level splitting.Comment: 8 pages, 2 figure

Multiphoton Bloch-Siegert shifts and level-splittings in spin-one systems

We consider a spin-boson model in which a spin 1 system is coupled to an oscillator. A unitary transformation is applied which allows a separation of terms responsible for the Bloch-Siegert shift, and terms responsible for the level splittings at anticrossings associated with Bloch-Siegert resonances. When the oscillator is highly excited, the system can maintain resonance for sequential multiphoton transitions. At lower levels of excitation, resonance cannot be maintained because energy exchange with the oscillator changes the level shift. An estimate for the critical excitation level of the oscillator is developed.Comment: 14 pages, 3 figure

Mucinous cystadenoma of the appendix: a diagnostic dilemma.

Mucinous cystadenoma of appendix is a rare clinical entity. We here report a case of an elderly male who presented in surgery outpatient department for routine check-up. Ultrasonography followed by CT scan of the abdomen did not give any conclusive diagnosis, following which exploratory laparotomy was done which was suggestive of appendiceal mucocele. The aim of reporting this case was to review the various clinical presentations and an optimum management of such incidental tumors

Properties of the integrated spectrum of serendipitous 2XMM catalogue sources

Our analysis is aimed at characterizing the properties of the integrated spectrum of active galactic nuclei (AGNs) such as the ubiquity of the Fe K{\alpha} emission in AGNs and the dependence of the spectral parameters on the X-ray luminosity and redshift. We selected 2646 point sources from the 2XMM catalogue at high galactic latitude (|BII| > 25 degrees) and with the sum of EPIC-PN and EPIC-MOS 0.2-12 keV counts greater than 1000. Redshifts were obtained for 916 sources from the NED. The final sample consists of 507 AGN. Individual source spectra have been summed in the observed frame to compute the integrated spectra in different redshift and luminosity bins over the range 0<z<5. Detailed analysis of these spectra has been performed. We find that the narrow Fe K{\alpha} line at 6.4 keV is significantly detected up to z=1. The line equivalent width decreases with increasing X-ray luminosity in the 2-10 keV band (''IT effect''). The anti-correlation is characterized by the relation log(EWFe) = (1.66 +/- 0.09) + (-0.43 +/- 0.07) log(LX,44), where EWFe is the rest frame equivalent width of the neutral iron K{\alpha} line in eV and LX,44 is the 2-10 keV X-ray luminosity in units of 10^{44} erg s^{-1}. The equivalent width is nearly independent of redshift up to z ~ 0.8 with an average value of 101+/-40 (rms dispersion) eV in the luminosity range 43.5<= logLX <= 44.5. Our analysis also confirmed the hardening of the spectral indices at low luminosities implying a dependence of obscuration on luminosity. We confirm that the neutral narrow Fe K{\alpha} line is an almost ubiquitous feature of AGNs. We find compelling evidence for the ''IT effect'' over a redshift interval larger than probed in any previous study. We detect no evolution of the average rest frame equivalent width of the Fe K{\alpha} line with redshift.Comment: 10 pages, 7 figures, 2 Tables. A&A in pres

Agro-morphological Diversity of High Altitude Bean Landraces in the Kailash Sacred Landscape of Nepal

Many varieties of bean are widely grown across diverse agro-ecological zones in Nepal. And opportunities exist for improving the crops and enhancing their resilience to various biotic and abiotic stressors. In this context, an experiment was conducted from June to October 2016 in Khar VDC of Darchula district to study the phenotypic traits of nine landraces of bean (Phaseolus vulgaris L.). The bean landraces were planted using randomized complete block design in three sites (Dhamidera, Dallekh and Sundamunda villages), with three replications in each site for their comparative analysis. The study considered the following phenotypic traits: days to emergence, days to 50% flowering, days to 90% pod maturity, number of nodes, pod length, pod width, number of pods, number of seeds per pod and weight and grain yield for 100 seeds. Kruskal-Wallis test showed significant differences in the landraces both within and among locations. KA-17-08-FB and KA-17-04-FB were late &nbsp;flowering (63 and 65 days respectively) compared to other landraces whereas KA-17-07-FB flowered earliest (within 42 days). In all three sites, three landraces namely KA-17-07-FB, KA-17-04-FB and KA-17-06-FB were found to be relatively more resistant to pest and diseases than other landraces. Eight out of nine landraces in Dhamidera and Dallekh villages and seven out of nine in Sundamunda village produced seeds greater than 1.0 t/ha. Among the nine varieties KA-17-02-FB was the highest yielding variety, with an average yield of 3.8 t/ha. This study is useful for identifying suitable landraces for future promotion based on their maturity, grain yield, diseases resistance and other qualitative and quantitative characteristics