A time frequency analysis of wave packet fractional revivals

We show that the time frequency analysis of the autocorrelation function is, in many ways, a more appropriate tool to resolve fractional revivals of a wave packet than the usual time domain analysis. This advantage is crucial in reconstructing the initial state of the wave packet when its coherent structure is short-lived and decays before it is fully revived. Our calculations are based on the model example of fractional revivals in a Rydberg wave packet of circular states. We end by providing an analytical investigation which fully agrees with our numerical observations on the utility of time-frequency analysis in the study of wave packet fractional revivals.Comment: 9 pages, 4 figure

On the relative fishing power of trawlers operated off Cochin

All vessels do not have same fishing power. The absolute fishing power of a vessel is measured in terms of the fishing mortality generated by it. But since the latter cannot be measured directly, a relative fishing power of a vessel has been defined as the ratio of the catch per unit fishing time of the vessel to that of another fishing vessel taken as standard when both are fishing on the same ground and the same density of fish. In this way, a fishing power can be allotted to each vessel. Once the relative fishing power of different vessels are known, it will be easy to Compute the total intensity of fishing effort, an accurate estimate of which is so essential in the study of stock assessments of fisheries

Trends in Molecular Emission from Different Extragalactic Stellar Initial Mass Functions

Banerji et al. (2009) suggested that top-heavy stellar Initial Mass Functions (IMFs) in galaxies may arise when the interstellar physical conditions inhibit low-mass star formation, and they determined the physical conditions under which this suppression may or may not occur. In this work, we explore the sensitivity of the chemistry of interstellar gas under a wide range of conditions. We use these results to predict the relative velocity-integrated antenna temperatures of the CO rotational spectrum for several models of high redshift active galaxies which may produce both top-heavy and unbiased IMFs. We find that while active galaxies with solar metallicity (and top-heavy IMFs) produce higher antenna temperatures than those with sub-solar metallicity (and unbiased IMFs) the actual rotational distribution is similar. The high-J to peak CO ratio however may be used to roughly infer the metallicity of a galaxy provided we know whether it is active or quiescent. The metallicity strongly influences the shape of the IMF. High order CO transitions are also found to provide a good diagnostic for high far-UV intensity and low metallicity counterparts of Milky Way type systems both of which show some evidence for having top-heavy IMFs. We also compute the relative abundances of molecules known to be effective tracers of high density gas in these galaxy models. We find that the molecules CO and CS may be used to distinguish between solar and sub-solar metallicity in active galaxies at high redshift whereas HCN, HNC and CN are found to be relatively insensitive to the IMF shape at the large visual magnitudes typically associated with extragalactic sources.Comment: 26 Pages, 8 Figures, Accepted for publication in Ap

Survey of the sea fisheries of India

A preliminary account is given of the design and technique of the sampling method employed for estimating the landings of sea fish at some selected centres along the East and West coasts of India. Statistics of marine fishing villages, fishing populations, boats and nets are presented along with app roximate percentages of the occurrence of important fishes and also the estimated monthly landings of fish during 1949 at some representauve places

Observations on the biology of Harpodon nehereus (Hamilton)

The total catch of Bombay duck in Inaia during 1949 was estimated as about- 7250 tons ie about 2% of the total yield of marine fishes of India. The fishing season commences, some time in Septembeer just after the South West monsoon and continues for a period of about 4 to 5 months. It is also available during the other months of the year in smaller numbers but is somewhat rare during May to August

Structure of the regulatory hyaluronan binding domain in the inflammatory leukocyte homing receptor CD44

Adhesive interactions involving CD44, the cell surface receptor for hyaluronan, underlie fundamental processes such as inflammatory leukocyte homing and tumor metastasis. Regulation of such events is critical and appears to be effected by changes in CD44 N-glycosylation that switch the receptor "on" or "off" under appropriate circumstances. How altered glycosylation influences binding of hyaluronan to the lectin-like Link module in CD44 is unclear, although evidence suggests additional flanking sequences peculiar to CD44 may be involved. Here we show using X-ray crystallography and NMR spectroscopy that these sequences form a lobular extension to the Link module, creating an enlarged HA binding domain and a formerly unidentified protein fold. Moreover, the disposition of key N-glycosylation sites reveals how specific sugar chains could alter both the affinity and avidity of CD44 HA binding. Our results provide the necessary structural framework for understanding the diverse functions of CD44 and developing novel therapeutic strategies

A preliminary appraisal of the prawn fishery of Kerala

A preliminary appraisal of the relation between fishing effort and catch of prawns in the Kerala waters has been made, using the prawn catch data available with the Central Marine Fisheries Research Institute and of the medium-sized vessels of the Government of India and the Indo-Norwegian Project operating along the Kerala coast from 1957 to 1969. The decline in catch per unit effort and the decline in the mean size of prawns in the commercial catches of Kerala are not signs of over-fishing but are indications of an expanding fishery. The analysis shows that very little increase in the catch will result even when the fishing effort is increased substantially and the immediate need is to stabilise the production at its present level

Examination of the efficiency of mackerel fishing

When various developmental measures are being undertaken to increase the fish production in India, it is pertinent to examine if the fishing methods employed are quite efficient. In marine fishing, the efficiency of fishing methods in general depends on the ability of the fishermen to locate the fishing grounds where the fish are abundant and to catch them there. In case of some of the pelagic fisheries like Indian mackerel, in the exploitation of which the fishermen rely on the arrival of the fish shoals in the inshore area, the fishing efficiency will depend on the ability and skill of the fishermen to identify the time and period when the mackerel shoals are most abundant in the inshore waters and to concentrate most of their effort at the time to catch the fish. The present paper provides a method for measuring quantitatively the fishing efficiency of the fishermen of the Karwar area with regard to the mackerel fishery. Though the results of the quantitative analysis will specifically relate to the efficiency of the Karwar fishermen, it is believed that the same will be applicable to the fishermen of the entire Mysore coast, if not the entire Indian coast