Quantum coherence and population trapping in three-photon processes

The spectroscopic properties of a single, tightly trapped atom are studied, when the electronic levels are coupled by three laser fields in an $N$-shaped configuration of levels, whereby a $\Lambda$-type level system is weakly coupled to a metastable state. We show that depending on the laser frequencies the response can be tuned from coherent population trapping at two-photon resonance to novel behaviour at three photon resonance, where the metastable state can get almost unit occupation in a wide range of parameters. For certain parameter regimes the system switches spontaneously between dissipative and coherent dynamics over long time scales

NASSAM: a server to search for and annotate tertiary interactions and motifs in three-dimensional structures of complex RNA molecules

Similarities in the 3D patterns of RNA base interactions or arrangements can provide insights into their functions and roles in stabilization of the RNA 3D structure. Nucleic Acids Search for Substructures and Motifs (NASSAM) is a graph theoretical program that can search for 3D patterns of base arrangements by representing the bases as pseudo-atoms. The geometric relationship of the pseudo-atoms to each other as a pattern can be represented as a labeled graph where the pseudo-atoms are the graph's nodes while the edges are the inter-pseudo-atomic distances. The input files for NASSAM are PDB formatted 3D coordinates. This web server can be used to identify matches of base arrangement patterns in a query structure to annotated patterns that have been reported in the literature or that have possible functional and structural stabilization implications. The NASSAM program is freely accessible without any login requirement at http://mfrlab.org/grafss/nassam/

Raman cooling and heating of two trapped Ba+ ions

We study cooling of the collective vibrational motion of two 138Ba+ ions confined in an electrodynamic trap and irradiated with laser light close to the resonances S_1/2-P_1/2 (493 nm) and P_1/2-D_3/2 (650 nm). The motional state of the ions is monitored by a spatially resolving photo multiplier. Depending on detuning and intensity of the cooling lasers, macroscopically different motional states corresponding to different ion temperatures are observed. We also derive the ions' temperature from detailed analytical calculations of laser cooling taking into account the Zeeman structure of the energy levels involved. The observed motional states perfectly match the calculated temperatures. Significant heating is observed in the vicinity of the dark resonances of the Zeeman-split S_1/2-D_3/2 Raman transitions. Here two-photon processes dominate the interaction between lasers and ions. Parameter regimes of laser light are identified that imply most efficient laser cooling.Comment: 8 pages, 5 figure

Motional sidebands and direct measurement of the cooling rate in the resonance fluorescence of a single trapped ion

Resonance fluorescence of a single trapped ion is spectrally analyzed using a heterodyne technique. Motional sidebands due to the oscillation of the ion in the harmonic trap potential are observed in the fluorescence spectrum. From the width of the sidebands the cooling rate is obtained and found to be in agreement with the theoretical prediction.Comment: 4 pages, 4 figures. Final version after minor changes, 1 figure replaced; to be published in PRL, July 10, 200

Quantum jumps induced by the center-of-mass motion of a trapped atom

We theoretically study the occurrence of quantum jumps in the resonance fluorescence of a trapped atom. Here, the atom is laser cooled in a configuration of level such that the occurrence of a quantum jump is associated to a change of the vibrational center-of-mass motion by one phonon. The statistics of the occurrence of the dark fluorescence period is studied as a function of the physical parameters and the corresponding features in the spectrum of resonance fluorescence are identified. We discuss the information which can be extracted on the atomic motion from the observation of a quantum jump in the considered setup

Fisheries, chaos and ethics: A note on India status

Historically in the world, since last century,fish stocks of many species have been overexploited. A good management of fisheries became essential to permit the preservation of species. Managing fisheries got increasingly complex, once many interests, often contradictory, are always involved. Moreover, through time, political will has not been enough to change things in many places around the world and overexploitation has remained for many species. In India, with a strong population density in many coastal areas depending on fishing, the situation is very severe for many species and new requirements for preservation are now being tried. In literature, fisheries have been analysed in contexts of uncertainty. Chaos theory is one of the theories that have been used to explain fisheries. This work intends to represent a reflection about fisheries overexploitation,considering the utilization of chaos theory and the understanding of the related problems taking into account ethics setting. The India situation is showed

A strategic profit model to measure Indian apparel retail performance

The strategic profit model (SPM) has been used to measure the performance of three Indian retail companies that focus in apparel. In the study three companies have been chosen to represent three groups of companies viz., large, medium and small corporate. In the case of large size, medium size and small size corporate, Pantaloon retail is considered with a turnover of Rs.3,031 crores, Shoppers’ stop retail with a turnover of Rs.849 crores and Provogue with a turnover of Rs.228 for the year 2007 have been included for the study, respectively. In order to find out the suitable strategies for the companies in the categories, the comparison has been done with its best performance as well as the indicators in relation to peer averages. The ROA has been noticed around 5 percent and the study attempt to reveal the appropriate strategy to increase it by 10 percent. The study has been carried out to indicate suitable strategies to maximize the performance in the future years for Indian apparel retail sector in line with the measure of RONW

Corporate Social Responsibility: An International Study The Case of CGD (Portugal), Vale (Brazil), TechnoLogica (Bulgaria) and IndianOil (India)

There are many studies in the area of Corporate Social Responsibility but the presentation of several cases in one study reveals some particular aspects to be considered and to be had in account when CSR is studied. There are developments on this matter showing that progressively an increasing number of companies are concerned about their performance on this subject and about reaching their objectives involving CSR. Corporate Social Responsibility shall have self-regulating mechanisms through which responsibilities shall be monitored. Companies shall ensure that law is guaranteed as far as ethical standards and international norms shall be assured as well. According to the 2001 European Commission Green Paper, Social Responsibility conceptualization is associated with the idea of companies deciding, in a voluntary base, to contribute for a fair society and a cleaner environment. Corporate social responsibility deals with the organizations’ actions intending to get a positive impact on several areas, such as environment, consumers, employees or communities, for instance. It demands a set of duties and obligations, to be induced on the relationship with the communities and the society in general in which the organization is integrated. In some countries, the corporate social responsibility is still a big challenge, since often the actions of social responsibility have not contributed effectively to develop the life situation of much people. This study emphasizes the general perspective of CSR in each one of these countries. CGD - Caixa Geral de Depósitos(Portugal), Vale (Brazil), TechnoLogica (Bulgaria) and IndianOil (India) are important companies concerned with the development of CSR activities; they have some very interesting results in this area

Heart Rate Variability in Response to a 3-day Kumbhaka Pranayama Practice

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Assessment of trace metal contamination in a historical freshwater canal (Buckingham Canal), Chennai, India

The present study was done to assess the sources and the major processes controlling the trace metal distribution in sediments of Buckingham Canal. Based on the observed geochemical variations, the sediments are grouped as South Buckingham Canal and North Buckingham Canal sediments (SBC and NBC, respectively). SBC sediments show enrichment in Fe, Ti, Mn, Cr, V, Mo, and As concentrations, while NBC sediments show enrichment in Sn, Cu, Pb, Zn, Ni, and Hg. The calculated Chemical Index of Alteration and Chemical Index of Weathering values for all the sediments are relatively higher than the North American Shale Composite and Upper Continental Crust but similar to Post-Archaean Average Shale, and suggest a source area with moderate weathering. Overall, SBC sediments are highly enriched in Mo, Zn, Cu, and Hg (geoaccumulation index (Igeo) class 4– 6), whereas NBC sediments are enriched in Sn, Cu,Zn, and Hg (Igeo class 4–6). Cu, Ni, and Cr show higher than Effects-Range Median values and hence the biological adverse effect of these metals is 20%; Zn, which accounts for 50%, in the NBC sediments, has a more biological adverse effect than other metalsfound in these sediments. The calculated Igeo, Enrichment Factor, and Contamination Factor values indicate that Mo, Hg, Sn, Cu, and Zn are highly enriched in the Buckingham Canal sediments, suggesting the rapid urban and industrial development of Chennai MetropolitanCity have negatively influenced on the surrounding aquatic ecosystem