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Viana M.P.,University of Sao Paulo | Batista J.L.B.,University of Sao Paulo | Costa L.D.F.,University of Sao Paulo | Costa L.D.F.,National Institute of Science
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

The measurement called accessibility has been proposed as a means to quantify the efficiency of the communication between nodes in complex networks. This article reports results regarding the properties of accessibility, including its relationship with the average minimal time to visit all nodes reachable after h steps along a random walk starting from a source, as well as the number of nodes that are visited after a finite period of time. We characterize the relationship between accessibility and the average number of walks required in order to visit all reachable nodes (the exploration time), conjecture that the maximum accessibility implies the minimal exploration time, and confirm the relationship between the accessibility values and the number of nodes visited after a basic time unit. The latter relationship is investigated with respect to three types of dynamics: traditional random walks, self-avoiding random walks, and preferential random walks. © 2012 American Physical Society.


Kaur H.,Medical College and Hospital | Gupta B.M.,National Institute of Science
Scientometrics | Year: 2010

The study examines India's performance based on its publication output in dental sciences during 1999-2008, based on several parameters, including the country annual average growth rate, global publication share & rank among 25 most productive countries of the world, national publication output and impact in terms of average citations per paper, international collaboration output and share and contribution of major collaborative partners, contribution and impact of select top 25 Indian institutions and select top 15 most productive authors, patterns of communication in national and international journals and characteristics of its 45 high cited papers. The study uses 10 years (1999-2008) publications data in dental sciences of India and other countries drawn from Scopus international multidisciplinary bibliographical database. © 2010 Akadémiai Kiadó, Budapest, Hungary.


Gupta B.M.,National Institute of Science
Annals of Library and Information Studies | Year: 2011

Analyses the ranking of the India's productive institutions in agricultural sciences, based on the basis of various quantitative indicators, such as the total number of papers and international collaborative papers and qualitative indicators, such as the average number of citations per paper and h-index value, and also in terms of a new composite indicator, which combines quantitative and qualitative aspects. Many institutions changed their ranking positions, when their ranking based on mean citation rate and h-index was compared with their ranking based on the composite indicator. Concludes that the ranking based on composite indicator gives much better results than other indicators as it combines both quantity and quality aspects.


Gupta B.M.,National Institute of Science | Bala A.,Government Medical College and Hospital
Lung India | Year: 2011

Objective: This study analyzes the research output of India in asthma during the period from 1999 till 2008. It analyzes the growth, rank and global publications share, citation impact, share of international collaborative papers, contribution of major collaborative partner countries and contribution of various subject fields. It also analyzes the characteristics of most productive institutions, authors and high-cited papers. Materials and Methods: SCOPUS database has been used to retrieve the data on publication output in asthma research. Results: India ranks 15th position among the top 23 countries in asthma research, with its global publication share of 1.27% (862 papers), registering an average citation per paper of 3.43 and achieved an h-index of 33 during 1999-2008. Conclusion: Indian research output on asthma is quite low in the global context as reflected from its publication output per thousand population (0.001) and its world publication share (1.27%) during 1999-2008. Also, the impact and quality of Indian research is low compared to select developed and developing countries.


Conifer C.,RWTH Aachen | Gunanathan C.,National Institute of science | Rinesch T.,RWTH Aachen | Holscher M.,RWTH Aachen | Leitner W.,RWTH Aachen
European Journal of Inorganic Chemistry | Year: 2015

Upon the simple addition of substrates, the ruthenium pincer complex [Ru(tBuPNP)(H2)(H)2] [1; tBuPNP = 2,6-bis(di-tert-butylphosphinomethyl) pyridine] is an active and selective catalyst system for the hydrosilylation of terminal alkyl alkynes under mild, solvent-free conditions. The reactivity of this system for other functionalized terminal alkynes was also investigated, and we observed competing catalytic cycles that produce both alkyne dimers and dehydrogenative silylation products. Kinetic measurements for the hydrosilylation of 1-octyne show that the catalyst has an initial turnover frequency of 121 h-1 at room temperature. The stoichiometric reaction between 1 and H2SiPh2 yields [Ru(tBuPNP)(H)2(H2SiPh2)], which undergoes Si-H bond activation to yield the catalytically active species [Ru(tBuPNP)-(HSiPh2)(H)]. The reaction of 1 with phenylacetylene yielded [Ru(tBuPNP)(H)2(HC≡CPh)] and [Ru(tBuPNP)(H)(C≡CPh)-(HC≡CPh)], and we propose that the latter is the active species in the dimerization reaction. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.


Gupta B.M.,National Institute of Science | Bala A.,Government Medical College and Hospital
Journal of Vector Borne Diseases | Year: 2011

Objective: This study analyses the research output of India in malaria research in national and global context, as reflected in its publications output during 1998-2009. Methods: SCOPUS Citation database has been used to retrieve the publication data, which has been further analyzed on several parameters including its growth, rank and global publications share, citation impact, overall share of international collaborative papers and share of major collaborative partners and patterns of research communication in most productive journals. The publications output, impact and collaborative publication share of India is also compared with South Africa, Brazil and China. Results: Indian scientists together have published 2786 papers in malaria research during 1998-2009 and registered an average citation per paper of 3.49. The country ranks 4th among the top 20 most productive countries in malaria research with its global publications share of 6.47% during 1998-2009. Conclusion: Quantum of Indian research output in malaria research is high but its citations per paper is low compared to select developing countries, which can be improved by investing more funds in international and national collaborative research projects, as well as increasing the participation of researchers in such projects.


Karthik G.,National Institute of Science | Lim J.M.,Yonsei University | Srinivasan A.,National Institute of Science | Suresh C.H.,Indian National Institute for Interdisciplinary Science and Technology | And 2 more authors.
Chemistry - A European Journal | Year: 2013

Two examples of core-modified 36π doubly fused octaphyrins that undergo a conformational change from a twisted figure-eight to an open-extended structure induced by protonation are reported. Syntheses of the two octaphyrins (in which Ar=mesityl or tolyl) were achieved by a simple acid-catalyzed condensation of dipyrrane unit containing an electron-rich, rigid dithienothiophene (DTT) core with pentafluorobenzaldehyde followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The single-crystal X-ray structure of the octaphyrin (in which Ar=mesityl) shows a figure-eight twisted conformation of the expanded porphyrin skeleton with two DTT moieties oriented in a staggered conformation with a π-cloud distance of 3.7 Å. Spectroscopic and quantum mechanical calculations reveal that both octaphyrins conform to a [4n]π nonaromatic electronic structure. Protonation of the pyrrole nitrogen atoms of the octaphyrins results in dramatic structural change, which led to 1) a large redshift and sharpening of absorption bands in electronic absorption spectrum, 2) a large change in chemical shift of pyrrole β-CH and-NH protons in the 1H NMR spectrum, 3) a small increase in singlet lifetimes, and 4) a moderate increase in two-photon absorption cross-section values. Furthermore, nucleus-independent chemical shift (NICS) values calculated at various geometrical positions show positive values and anisotropy-induced current density (AICD) plots indicate paratropic ring-currents for the diprotonated form of the octaphyrin (in which Ar=tolyl); the single-crystal X-ray structure of the diprotonated form of the octaphyrin shows an extended structure in which one of the pyrrole ring of each dipyrrin subunit undergoes a 180 ° ring-flip. Four trifluoroacetic acid (TFA) molecules are bound above and below the molecular plane defined by meso-carbon atoms and are held by NH×××O, N-H...F, and C-H...F intermolecular hydrogen-bonding interactions. The extended-open structure upon protonation allows π-delocalization and the electronic structure conforms to a [4n]π Hückel antiaromatic in the diprotonated state. Figure-eight to open structure: A major structural change from a figure-eight conformation to an open-extended conformation upon addition of two protons to an expanded 36π fused octaphyrin cavity is reported (see figure). Such a change in conformation results in an increase in singlet lifetime, two-photon absorption cross-section values, and a change in aromaticity from a (4n)π nonaromatic to antiaromatic electronic structure. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gupta B.M.,National Institute of Science | Bala A.,Government Medical College and Hospital
Asian Journal of Psychiatry | Year: 2013

Objectives: This study analyses the research output of India in schizophrenia research during 2002-11 on several parameters including the growth, rank and global publications share, citation impact, share of international collaborative papers, contribution of major collaborative partner countries, contribution of various subject-fields, contribution and impact of most productive institutions and authors, media of communication and characteristics of high cited papers. Methods: The Scopus Citation Database has been used to retrieve the data for 10 years (2002-11) by searching the keywords schizophrenia research in the combined Title, Abstract and Keywords fields. Results: Among the top 20 most productive countries in schizophrenia research, India ranks at 15th position (with 882 papers) with a global publication share of 1.58% and an annual average publication growth rate of 21.80% during 2002-11. Its citation impact per paper was 3.60 international collaborative publications share was 26.98% during 2002-11. Conclusions: Concludes that India needs to increase both the quantity and quality of research and also increase the international collaborative research, besides strengthening and modernizing its research infrastructure. There is need to treat schizophrenia as a priority area in the current and future national S & T plans of India. © 2013 Elsevier B.V.


Bala A.,Government Medical College and Hospital | Gupta B.M.,National Institute of Science
Neurology India | Year: 2010

Objective : This study analyses the research output in India in neurosciences during the period 1999-2008 and the analyses included research growth, rank, global publications' share, citation impact, share of international collaborative papers and major collaborative partner countries and patterns of research communication in most productive journals. It also analyses the characteristics of most productive institutions, authors and high-cited papers. The publication output and impact of India is also compared with China, Brazil and South Korea. Materials and Method s: Scopus Citation database was used for retrieving the publications' output of India and other countries in neurosciences during 1999-2008. Results : India's global publications' share in neurosciences during the study period was 0.99% (with 4503 papers) and it ranked 21st among the top 26 countries in neurosciences. The average annual publication growth rate was 11.37%, shared 17.34% of international collaborative papers and the average citation per paper was 4.21. India was far behind China, Brazil and South Korea in terms of publication output, citation quality and share of international collaborative papers in neurosciences. Conclusion : India is far behind in terms of publication output, citation quality and share of international collaborative papers in neurosciences when compared to other countries with an emerging economy. There is an urgent need to substantially increase the research activities in the field of neurosciences in India.


Gupta B.M.,National Institute of Science | Bala A.,Government Medical College and Hospital
Journal of Natural Science, Biology and Medicine | Year: 2011

Objective: This study analyzes the research activities of India in medicine during 1999-2008, based on the total publication output, its growth rate, quality of papers published and rank of India in the global context. Patterns of international collaborative research output and the major partner countries of India are also discussed. This study also evaluates the research performance of different types of Indian medical colleges, hospitals, research institutes, universities and research foundations and the characteristics of published literature in Indian and foreign journals. It also analyzes the medical research output by disease and organs. Materials and Methods: The publication data on medicine has been retrieved by using SCOPUS database. Results: India holds 12th rank among the productive countries in medicine research consisting of 65,745 papers with a global publication share of 1.59% and registering a growth rate of 76.68% for the papers published during 1999-2003 to 2004-2008. Conclusion: High quality research in India is grossly inadequate and requires strategic planning, investment and resource support. There is also a need to improve the existing medical education system, which should foster research culture.

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