On the Real Spectra of Calogero Model with Complex Coupling

We study the eigenvalue problem of the rational Calogero model with the coupling of the inverse-square interaction as a complex number. We show that although this model is manifestly non-invariant under the combined parity and time-reversal symmetry ${\cal{PT}}$, the eigenstates corresponding to the zero value of the generalized angular momentum have real energies.Comment: revtex4 8 pages, 2 figure

Yield of aerobic rice affected by high temperature stress during summer season -A study from red and laterite zone of West Bengal, India

Field experiment on the performance of aerobic direct seeded rice (ADSR) under red and laterite zone of West Bengal was conducted at Rice Research Station, Bankura, West Bengal, India during summer season, 2012. The experimental soil was sandy loam with acidic in nature (pH: 5.2). The results exhibited that the grain yield (1 t ha-1) of rice in aerobic situation was low. This might be due to high atmospheric temperature during flowering period, which results in poor grain setting in panicle and most of them became chaffy due to spikelet sterility. Ultimately, it produced low grain yield of rice in aerobic situation during summer season due to high temperature at flowering period, grain formation and grain ripening stages. Thus, aerobic rice system of cultivation needed good management practices

W40 region in the Gould Belt : An embedded cluster and H II region at the junction of filaments

We present a multiwavelength study of W40 star-forming region using IR observations in UKIRT JHK bands, Spitzer IRAC bands & Herschel PACS bands; 2.12 micron H2 narrow-band imaging; & radio observations from GMRT (610 & 1280 MHz), in a FoV of ~34'x40'. Spitzer observations along with NIR observations are used to identify 1162 Class II/III & 40 Class I sources in the FoV. The NN stellar surface density analysis shows that majority of these YSOs constitute the embedded cluster centered on the source IRS1A South. Some YSOs, predominantly younger population, are distributed along & trace the filamentary structures at lower stellar surface density. The cluster radius is obtained as 0.44pc - matching well with the extent of radio emission - with a peak density of 650pc^-2. The JHK data is used to map the extinction which is subsequently used to compute the cloud mass. It has resulted in 126 Msun & 71 Msun for the central cluster & the northern IRS5 region, respectively. H2 narrow-band imaging displays significant emission, which prominently resembles fluorescent emission arising at the borders of dense regions. Radio analysis shows this region as having blister morphology, with the radio peak coinciding with a protostellar source. Free-free emission SED analysis is used to obtain physical parameters of the overall region & the IRS5 sub-region. This multiwavelength scenario is suggestive of star formation having resulted from merging of multiple filaments to form a hub. Star formation seems to have taken place in two successive epochs, with the first epoch traced by the central cluster & the high-mass star(s) - followed by a second epoch which is spreading into the filaments as uncovered by the Class I sources & even younger protostellar sources along the filaments. The IRS5 HII region displays indications of swept-up material which has possibly led to the formation of protostars.Comment: 17 pages, 12 figures, 2 tables. Accepted for publication in The Astrophysical Journa

The Housing Market and the Credit Default Swap premium in the UK Banking Sector: A VAR Approach

In the wake of the recent global financial crisis, this paper investigates the determinants of the Credit Default Swap premium in the UK banking sector for the period January 2004-April 2011. Employing a VAR model, we focus on the roles played by house prices, the yield spread, the UK TED spread and the FTSE 100 index. Our main results suggest that the CDS premium significantly increases in the medium term following a positive shock to the house price index, reflecting that continued house price appreciation can hide the likelihood of default risk, as shown in the insignificant response in the short run. We also find that a positive shock to the CDS premium significantly reduces house prices because it induces banks and other financial institutions to lend less, reducing the demand for housing and exerting further downward pressure on house prices. While a positive shock to stock prices lowers CDS premium, a positive shock to the liquidity premium increases CDS premium. Finally, our variance decomposition analysis shows that the house price shock explains over 19% of the long-run forecast-error variance of the CDS premium, while shocks in other variables each explain less than 8% of this forecast-error variance

NGC 7538 : Multiwavelength Study of Stellar Cluster Regions associated with IRS 1-3 and IRS 9 sources

We present deep and high-resolution (FWHM ~ 0.4 arcsec) near-infrared (NIR) imaging observations of the NGC 7538 IRS 1-3 region (in JHK bands), and IRS 9 region (in HK bands) using the 8.2m Subaru telescope. The NIR analysis is complemented with GMRT low-frequency observations at 325, 610, and 1280 MHz, molecular line observations of H13CO+ (J=1-0), and archival Chandra X-ray observations. Using the 'J-H/H-K' diagram, 144 Class II and 24 Class I young stellar object (YSO) candidates are identified in the IRS 1-3 region. Further analysis using 'K/H-K' diagram yields 145 and 96 red sources in the IRS 1-3 and IRS 9 regions, respectively. A total of 27 sources are found to have X-ray counterparts. The YSO mass function (MF), constructed using a theoretical mass-luminosity relation, shows peaks at substellar (~0.08-0.18 Msolar) and intermediate (~1-1.78 Msolar) mass ranges for the IRS 1-3 region. The MF can be fitted by a power law in the low mass regime with a slope of Gamma ~ 0.54-0.75, which is much shallower than the Salpeter value of 1.35. An upper limit of 10.2 is obtained for the star to brown dwarf ratio in the IRS 1-3 region. GMRT maps show a compact HII region associated with the IRS 1-3 sources, whose spectral index of 0.87+-0.11 suggests optical thickness. This compact region is resolved into three separate peaks in higher resolution 1280 MHz map, and the 'East' sub-peak coincides with the IRS 2 source. H13CO+ (J=1-0) emission reveals peaks in both IRS 1-3 and IRS 9 regions, none of which are coincident with visible nebular emission, suggesting the presence of dense cloud nearby. The virial masses are approximately of the order of 1000 Msolar and 500 Msolar for the clumps in IRS 1-3 and IRS 9 regions, respectively.Comment: 27 pages, 18 figures, 5 tables. Accepted for publication in MNRA

Reliability investigation for a built ultrahigh concentrator prototype

This is the final version of the article. Available from AIP Publishing via the DOI in this record.Ultrahigh concentrator photovoltaics hold a great potential in both reducing the cost of photovoltaic energy and to higher conversion efficiencies. The challenges in their design and manufacturing however have not yet permitted a reliable ultrahigh ( > 2000X) system. Here we propose an ultrahigh concentrator photovoltaic design of 5800X geometrical concentration ratio based on multiple primary Fresnel lenses focusing to one central solar cell. The final stage optic is of a novel design to accept light from four different directions and focus the light towards the solar cell. The extremely high geometrical concentration of 5800X was chosen in anticipation of the losses accompanied with ultrahigh concentration due to alignment difficulties. The system was designed with manufacturability as one of the priorities and resulted in easily achieving > 2000X concentration for a first prototype with non-achromatic Fresnel lenses and in house secondarys. Higher concentrations are anticipated for future prototypes but investigation into the cell performance is required. An acceptance angle of 0.4°was achieved for this design which is considered good for such an ultrahigh concentration level and what's more, even at higher misalignment angles (such as 0.8 or 1 degree) ultrahigh concentration ratios are still achieved in simulations. Such a design could be the breakthrough in concentrator photovoltaic research for reaching higher concentration ratios. The use of flat optics to ease manufacturing and alignment is a simple but effective method to achieve a reliable system that will achieve ultrahigh concentration even at 36% optical efficiency. Such a design will be of use in investigations of concentration, concentrator solar cell development, temperature effects and more; achieving ultrahigh concentration levels not yet tested.The authors acknowledge the funding bodies of the SUNTRAP project and as part of the encouragement of open access data, any part of the presented investigation and results can be given upon email request to the authors

Thermal Performance of a Solar Concentrating Photovoltaic Module with Spiral Mini Channel Heat Sink

ICP 2015: International Conference on Polygeneration, Chennai, India, 18-20 February 2015Concentrating Photovoltaic (CPV) power generation is one of the attractive choices for efficient utilization of solar energy due to its high cogeneration efficiency. The increase in temperature of solar CPV cell significantly reduces the performance. The efficiency of a CPV system can be improved by introducing effective thermal management or cooling system. In this paper, a new spiral mini channel heat sink with rectangular cross section is developed and its performance is numerically analysed using commercial CFD software ANSYS 14. The mini-channels provided high heat transfer over cell surface area and resulted in lower pressure drop. The coolant outlet temperature rise across the mini-channel is estimated as 343K in CPV module of 300 X 300 mm2 and with a pressure drop of 8.043 k Pa at a flow rate of 0.16 liter/s. Based on numerical simulations, it is found that the optimum configuration of micro-channel with 4mm width and height of 20mm, having higher figure of merit.Department of Science and Technology (DST), Government of Indi