Aspects of coherent states of nonlinear algebras

Various aspects of coherent states of nonlinear $su(2)$ and $su(1,1)$ algebras are studied. It is shown that the nonlinear $su(1,1)$ Barut-Girardello and Perelomov coherent states are related by a Laplace transform. We then concentrate on the derivation and analysis of the statistical and geometrical properties of these states. The Berry's phase for the nonlinear coherent states is also derived.Comment: 22 Pages, 30 Figure

Contribution of Galaxies to the Background Hydrogen-Ionizing Flux

We estimate the evolution of the contribution of galaxies to the cosmic background flux at $912 \AA$ by means of a semi-analytic model of galaxy formation and evolution. Such a modelling has been quite successful in reproducing the optical properties of galaxies. We assume hereafter the high-redshift damped Lyman-$\alpha$ (DLA) systems to be the progenitors of present day galaxies, and we design a series of models which are consistent with the evolution of cosmic comoving emissivities in the available near infrared (NIR), optical, ultraviolet (UV), and far infrared (FIR) bands along with the evolution of the neutral hydrogen content and average metallicity of damped Lyman-$\alpha$ systems (DLA). We use these models to compute the galactic contribution to the Lyman-limit emissivity and background flux for $0 \simeq z \le 4$. We take into account the absorption of Lyman-limit photons by HI and dust in the interstellar medium (ISM) of the galaxies. We find that the background Lyman-limit flux due to galaxies might dominate (or be comparable to) the contribution from quasars at almost all redshifts if the absorption by HI in the ISM is neglected. The ISM HI absorption results in a severe diminishing of this flux--by almost three orders of magnitude at high redshifts to between one and two orders at $z \simeq 0$. Though the resulting galaxy flux is completely negligible at high redshifts, it is comparable to the quasar flux at $z \simeq 0$.Comment: 14 pages, 5 figures, requires mn.sty, accepted for publication in MNRA

The role of social cognition in decision making

Successful decision making in a social setting depends on our ability to understand the intentions, emotions and beliefs of others. The mirror system allows us to understand other people's motor actions and action intentions. ‘Empathy’ allows us to understand and share emotions and sensations with others. ‘Theory of mind’ allows us to understand more abstract concepts such as beliefs or wishes in others. In all these cases, evidence has accumulated that we use the specific neural networks engaged in processing mental states in ourselves to understand the same mental states in others. However, the magnitude of the brain activity in these shared networks is modulated by contextual appraisal of the situation or the other person. An important feature of decision making in a social setting concerns the interaction of reason and emotion. We consider four domains where such interactions occur: our sense of fairness, altruistic punishment, trust and framing effects. In these cases, social motivations and emotions compete with each other, while higher-level control processes modulate the interactions of these low-level biases

Spatial price integration and price transmission among major fish markets in India

The domestic fish marketing system in India deserves to be developed into a strong network of efficiently functioning markets, as more than three-fourths of the country’s total fish production is channellised domestically. With the unleashing of a new global economic order, the efficiency of markets needs to be dealt with utmost importance. The degree of spatial market integration and price transmission between the major coastal markets in India have been reported using monthly retail price data on important marine fish species. It has been observed that degree of integration and rate of price transmission differ according to species. The highest integration has been observed in mackerel, probably because of its affordability to all income classes, resulting in a wide consumer base. Among various markets, a near full transmission of prices has been observed between Kerala and Tamil Nadu markets, except in the case of shrimp. Even though a major landing centre, the price movement in Maharashtra market has been found independent of other markets. The spatial market integration between major shrimp markets in the country has appeared to be the least, possibly because of its greater market share outside the country. The study has suggested to devise strategies to bring about greater integration between these markets so that both fishermen and the fish-consuming community in the country are benefitted.Marketing,

Improving Search Rank by Optimizing TTFB

Now a days, everyone is in a great hurry and no one waits for turtles. Studies have shown that the search ranking are affected by how fast the web page loads. The simple logic behind this is “ A website which takes too much time to load provide poor user experience, today's user would quickly shift to next search result and you will end up loosing one“. The big search engine giant, Google search uses large number of parameters for determining search rankings which are mostly related to the content on your website, URL , social metrics, quality, quantity, SSL certificates, etc. In 2010, Google added one more factor in search ranking which is websites speed. TTFB (Time To First Byte) provides a clear way to determine how fast/slow there web page loads. Hence, here I'm focusing on improving website search engine ranking by applying various techniques to optimize TTF