| 1. |
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| 2. |
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| 3. |
- Bikkina, Srinivas, et al.
(författare)
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Atmospheric deposition of phosphorus to the Northern Indian Ocean
- 2015
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Ingår i: Current Science. - 0011-3891. ; 108:7, s. 1300-1305
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Tidskriftsartikel (refereegranskat)abstract
- Air- sea deposition of phosphorus is an important external source of this macronutrient for ocean primary productivity. Although global budgets have shown that atmospheric input of phosphorus is comparable to its riverine supply, studies on regional scale are rather limited. The present article summarizes sources and atmospheric pathway of phosphorus to the ocean surface as a case study of the Northern Indian Ocean. Water-soluble aerosol phosphorus (PInorg) concentrations are significantly high over the Bay of Bengal (BoB) compared to those over the Arabian Sea (ARS). Relative increase in the supply of aerosol-P over BoB is attributed to acid-processing of mineral dust during long-range atmospheric transport in addition to its supply from anthropogenic sources. Our estimate of P-deposition to the Northern Indian Ocean (similar to 1.2 Gmol-P year-1) is comparable to its atmospheric deposition in other oceanic regions such as the North Atlantic and is also consistent with the model-based projections for the Northern Indian Ocean. These results highlight the importance of atmospheric source in influencing the biogeochemical cycle of phosphorus in the Northern Indian Ocean.
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| 4. |
- Björn, Lars Olof, et al.
(författare)
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Detectability of life and photosynthesis on exoplanets.
- 2009
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Ingår i: Current Science. - 0011-3891. ; 96:9, s. 1171-1175
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- ‘Is there life on exoplanets?’. We refer to exoplanets as planets in other solar systems than our own. This often asked question can be further refined by asking ‘is there life on exoplanets which is so extensive that it may impact on its atmosphere, its biosphere and its optical properties?’. And if such a life exists, at astronomical distances from us, can we detect it with instruments on Earth-based or Earth-orbiting observatories? Will then, in that case, our advanced knowledge of present-day and early-day photosynthesis on Earth help us select appropriate biosignatures that may signal its presence? Here we elaborate further on these themes, based on the most recent literature, and from the point of view of photosynthesis. We also provide our considered views. Although search for chlorophyll is considered desirable, we conclude that our best bet is to look for and analyse photosynthesis-related gases, namely O2, CO2 and H2O vapour. We shall keep in mind that the evolutionary tree of life on our planet has its roots in autotrophy, and of the various forms of autotrophy, only oxygenic
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| 5. |
- Björn, Lars Olof, et al.
(författare)
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The evolution of photosynthesis and chloroplasts
- 2009
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Ingår i: Current Science. - 0011-3891. ; 96:11, s. 1466-1474
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Forskningsöversikt (refereegranskat)abstract
- This review focuses on what has been learned about the evolution of photosynthesis in the past five years, and omits evolution of CO2 assimilation. Oxygenic photosynthesis (using both photosystems I and II) has evolved from anoxygenic photosynthesis. The latter occurs in different variants, using either a type 1 photosystem resembling photosystem I, or a type 2 photosystem resembling photosystem II. Opinions differ as to how two types of photosystem came to be combined in the same organism, whether by gene transfer between bacteria, by fusion of bacteria, or as a result of gene duplication and evolution within one kind of bacterium. There are also different opinions about when oxygenic photosynthesis arose, in conjunction with the Great Oxygenation Event, 2.3 billion years before the present, or more than a billion years before that. Cyanobacteria were the first organisms to carry out oxygenic photosynthesis. Some of them gave rise to chloroplasts, while others continued to evolve as independent organisms, and the review outlines both lines of evolution. At the end we consider the evolution of photosynthesis in relation to the evolution of our planet.
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| 6. |
- Choubey, Sandhya
(författare)
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Neutrino oscillations
- 2017
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Ingår i: Current Science. - : Indian National Science Academy. - 0011-3891. ; 112:7, s. 1381-1384
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Tidskriftsartikel (refereegranskat)abstract
- Neutrinos are massless as proposed in the Standard Model of particle physics. However, neutrino experiments in the last few decades have revealed that neutrinos flavour oscillate, a scenario possible only if they have mass and mixing. Existence of neutrino mass was the first conclusive evidence of physics beyond the Standard Model, and explaining the smallness of the neutrino masses and peculiar mixing angles still remains a challenge for model-builders proposing beyond Standard Model scenarios. We give a brief introduction to the phenomenon of neutrino oscillations and showcase some recent work where we look for physics beyond the three-generation neutrino oscillation paradigm and its impact on future experiments.
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| 7. |
- Choudhary, P., et al.
(författare)
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Comparison of bulk organic matter characteristics in sediments of three Kumaun Himalayan lakes
- 2009
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Ingår i: Current Science. - 0011-3891. ; 97:4, s. 572-575
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Tidskriftsartikel (refereegranskat)abstract
- Three lakes (Nainital, Sattal and Naukuchiatal) in the Kumaun Himalayan region were investigated for total organic carbon (TOC%) and nitrogen (N%), their atomic ratios (C/N) and isotopic composition (delta C-13 and delta N-15) in their sediments. These geochemical proxies measured in 35-45 cm long cores indicate that organic matter preserved in the lake sediments is primarily derived from algal matter. Increase in TOC in all the three lakes suggests increased productivity. The sediments are anoxic in all the three lakes and show low N%. Shift in delta C-13 isotopic composition indicates influence of sewage input into the lakes. Likewise, increase in delta N-15 in surface sediments suggests nitrogen fixation by cyanobacteria.
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| 8. |
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| 9. |
- Erlandsson, Ragnar, et al.
(författare)
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Progress in scanning probe microscopy : High resolution force microscopy and spectroscopy
- 2000
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Ingår i: Current Science. - 0011-3891. ; 78:12, s. 1445-1457
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Tidskriftsartikel (refereegranskat)abstract
- During the last few years the Atomic Force Microscope (AFM) has become capable of routinely obtaining atomic resolution when operated with a vibrating cantilever (ac-mode). Local measurement of the tip-sample force (force spectroscopy) is a powerful tool for investigations of contact phenomena at the atomic scale that are important in fields like friction, tribology, atom manipulation and chemical bond formation. This paper reviews several aspects of the AFM technique such as tip-surface forces, force sensors, operation modes and contrast effects. A study of the Si(111)7 x 7 reconstruction is presented as an example of high resolution AFM imaging.
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| 10. |
- Grek, G.R., et al.
(författare)
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Experimental study of a Λ-structure development and its transformation into the turbulent spot
- 2000
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Ingår i: Current Science. - 0011-3891. ; 79:6, s. 781-789
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results of experimental research on the characteristics of Λ-structures, their development, and the mechanism of their transformation into turbulent spots. It has been shown that an isolated Λ-structure can damp as well as increase downstream and transform into a turbulent spot. The structure of the associated disturbances consists of two counter-rotating vortices (the "legs" of disturbance) closed by a "head" at the leading edge. The difference between the two types is that the Λ-structure that damps is a kind of a hairpin vortex which does not cross the upper boundary layer edge; the "head" of the increasing Λ-structure crosses the upper boundary layer edge and the disturbance attains the form of the Greek letter Λ. It has been proposed that the increasing Λ-structure is connected with the development of secondary high frequency disturbances on the "legs" of the structure. The reason for this is probably the local transverse velocity gradient ∂u / ∂z on the "legs" of the Λ-structure, which creates conditions for the development of secondary disturbances in it. It has also been shown that the frequency of the secondary disturbance decreases because of the continuous extension of a localized disturbance under its downstream propagation. Secondary high frequency breakdown of structures is also observed when there is periodical generation.
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| 11. |
- Josefsson, Johan, et al.
(författare)
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Heritage as life-values : a study of the cultural heritage concept
- 2016
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Ingår i: Current Science. - : Current Science Association. - 0011-3891. ; 110:11, s. 2091-2098
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Tidskriftsartikel (refereegranskat)abstract
- For a long time now, the world has been facing a heritage stampede with an array of stakeholders - nations, global heritage organizations, NGOs, terrorists and ordinary people - all claiming their rights to heritage and the past. Hence, there is a great need to understand what heritage does, or what we do with heritage in an everyday context. This article aims to contribute to the discussion through studies of the heritage concept from a theoretical and analytical perspective, starting from a Swedish and European view on heritage; how it came into being, established itself and developed, and finally found itself called into question and at risk of being discarded. Our argument is that the present heritage concept would benefit from the introduction of the concept of life-values, not in order to replace it, but to enrich and take heritage into the 21st century. The article is based on field work in Albania.
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| 12. |
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| 13. |
- KANDURI, C, et al.
(författare)
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GENES WITHOUT PROTEIN PRODUCTS : IS H19 THE NORM OR THE EXCEPTION?
- 1999
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Ingår i: Current science. - 0011-3891. ; 77:4, s. 539-544
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- The increasing number of RNA polymease II transcripts without any apparent open reading frame has increased our awareness that gene functions can be selected for without involving a protein product.By using the H19 gene as a point of reference, we highlight here several common features among non-coding genes, such as their antisense position in subchromosomal expression domains which are often genomically imprinted. We also discuss the need to critically examine the translatability of transcripts which are considered non-coding. Finally, we present a model to explain the origin of non-coding genes.
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| 14. |
- Karlsson, Niklas
(författare)
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The crossroads of academic electronic availability : how well does Google Scholar measure up against a university-based metadata system in 2014?
- 2014
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Ingår i: Current Science. - 0011-3891. ; 107:10, s. 1661-1665
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Tidskriftsartikel (refereegranskat)abstract
- Electronic availability of information resources has increasingly become an important part of everyday vocation of academic libraries. This puts impetus on the libraries to know more about the way in which electronic information is being dispersed and handled. The present article aims to comparatively evaluate Uppsala University library's own metadata system Summon with the free, publicly available equivalent Google Scholar (GS). The evaluation is based on Peter Jacso's theories on database evaluation which puts focus on Summon and GS via the use and application of ten different criteria. The uses of precision and relevance criteria were also implemented as additional evaluation tools. The results indicate that at present GS has to be seen as a necessary complement in retrieving electronic information due to the fact that Summon is not yet fully functioning on all levels and that GS has a wider intake of information sources. The use of web-based academic search tools is now vital. Will the open access movement evolve with Google as the main actor and take over the scene leaving costly databases and search tools behind? This article deals with the economic implications of comparing the practical functions of a costly in-house information system with a public equivalent. It reveals the complex situation that a world-class university is in as regards to information resources and the digitization and economic issues that follow.
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| 15. |
- Karunaratne, B. A., et al.
(författare)
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Effect of alumina filler on spherulite growth and ionic conductivity of PEO9(LiClO4) solid polymer electrolyte
- 2021
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Ingår i: Current Science. - : Current Science Association. - 0011-3891. ; 120:5, s. 900-906
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Tidskriftsartikel (refereegranskat)abstract
- The effect of incorporation of alumina on conductivity and in situ growth of spherulites in (PEO)(9)LiClO4 solid polymer electrolyte was studied using polarized microscopy, impedance and infrared spectroscopy. Fourfold enhancement in ionic conductivity correlated with increase in the amorphous nature of the polymer electrolyte was observed with the addition of 15 wt% of alumina having 5.5 nm pore size. The addition of 5 wt% of alumina with pore size <10 mu m, increased the ionic conductivity by nearly 3%. Filler particles may act as nuclei for the spherulites, while preventing the recrystallization tendency of the polymer and hence increase its conductivity.
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| 16. |
- Kitambi, Satish Srinivas, et al.
(författare)
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Teleost fish - Powerful models for studying development, function and diseases of the human eye
- 2011
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Ingår i: Current Science. - 0011-3891. ; 100:12, s. 1815-1823
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Tidskriftsartikel (refereegranskat)abstract
- The human eye is a highly specialized structure and defects in its development or functioning process have an impact on the quality of life. Different animal models, especially murine models, have been used to identify the key molecular players required for the normal functioning of the eye. This review highlights the importance of the teleost model in dissecting the development, functioning process and diseases of the human eye. A high degree of conservation is seen in the development, organization and function of the eye throughout vertebrates. Vertebrate teleost models, zebrafish and medaka, have become popular to study various aspects of developmental biology and genetics. Teleost eye shows high similarity to that of the mammalian eye; for example, as seen in mammals, the retina of zebrafish and medaka shows six types of neurons and one type of glia arranged in three layers. In addition, rapid embryonic development, transparency during early development, and the availability of various biochemical, molecular and genetic techniques applicable on these models facilitate in dissecting the developmental and functioning processes of the eye. The availability of mutants with eye defects in zebrafish and medaka allows the possibility of utilizing these two species as comparative models in gaining rapid understanding of the developmental events of various human diseases. The small size of these fish embryos and their availability in large numbers allow performing medically relevant chemical screens to identify potential drug and/or drug targets for different human eye conditions.
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| 17. |
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| 18. |
- Kumar Das, Supriyo, et al.
(författare)
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Biogeochemistry of shallow lake sediments: a case study from Verlorenvlei, South Africa
- 2015
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Ingår i: Current Science. - : INDIAN ACAD SCIENCES. - 0011-3891. ; 109:8, s. 1486-1491
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Tidskriftsartikel (refereegranskat)abstract
- Studying the biogeochemistry of shallow lake sediments, especially the source of sedimentary organic matter (OM), is challenging because of the low preservation of OM in shallow lake sediments. Here we report the source of sedimentary OM in a shallow freshwater lake, Verlorenvlei, in South Africa using a number of biogeochemical proxies. Elemental carbon and nitrogen ratio (C/N), and stable C and N isotopes (delta C-13 and delta N-15) indicate algal source of the sedimentary OM. Total organic and inorganic C, different phosphorus fractions, delta C-13 and delta N-15 values indicate repetitive presence of non-N-fixing cyanobacteria under moderate N-limited conditions. Cyanobacterial population in Verlorenvlei is likely influenced by the availability of dissolved inorganic C. Cyanobacterial proliferation in the lake has ceased with accelerated N input as recorded at the top of the core.
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| 19. |
- Kumar, R. P. S. Abhijith, et al.
(författare)
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Stabilization of the C-20 cage by encapsulation of H+ and He2+ ions
- 2014
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Ingår i: Current Science. - 0011-3891. ; 106:9, s. 1255-1259
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Tidskriftsartikel (refereegranskat)abstract
- It is shown by ab initio calculations using second-order Moller-Plesset perturbation theory and 6-31g*, aug-cc-pVDZ and aug-cc-pVTZ basis sets and coupled cluster singles, doubles and perturbative triples method with the 6-31g* basis set, that it is possible to stabilize the cage structure of the smallest fullerene C-20 by encapsulating small cations like H+ and He2+. While the latter stabilizes the cage structure by charge transfer, the former prefers to form a covalent linkage with the carbon atoms.
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| 20. |
- Persson, Olle, 1949-, et al.
(författare)
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Citation analysis to reconstruct the dynamics of Antarctic ozone hole research and formulation of the Montreal Protocol
- 2013
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Ingår i: Current Science. - 0011-3891. ; 104:7, s. 835-840
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Tidskriftsartikel (refereegranskat)abstract
- The ozone layer acts like a shield in safeguarding the Earth by preventing the harmful ultraviolet radiations from entering into the atmosphere. Reported damage to the ozone layer in 1985 was a significant milestone in Antarctic science research. The research work played a significant role in generating international socio-political debate on this great environmental crisis. This article aims to reconstruct the intellectual developments in the field and identify important scientific events which contributed to the formulation of the world’s most successful multilateral treaty, the Montreal Protocol. The dynamics of the research field was mapped using a newly developed indicator – weighted direct citations (WDC). The WDC value indicates intellectual closeness between two citations in terms of co-citations and shared references. Direct citations were weighted with shared references and co-citations to derive WDC values. An attempt was made to decompose the citation network of articles to identify significant activity layers. The work of J. C. Farman et al. (1985) and S. Solomon (1986), which are the top two most cited significant papers in the subject accounts for top WDC values jointly.
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| 21. |
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| 22. |
- Saxena, SK
(författare)
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Earth's core
- 1995
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Ingår i: CURRENT SCIENCE. - : CURRENT SCIENCE ASSN. - 0011-3891. ; 69:11, s. 914-917
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The new techniques of heating solids with a laser at ultra high pressure in a diamond-anvil cell are providing us with new data on equation of state properties of solid and molten iron. The new data on iron melting, which extends to a pressure of nearly 2
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| 23. |
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| 24. |
- Singh, Arvind, et al.
(författare)
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Inter- and intra-specific carbon and nitrogen assimilation by dinoflagellate and diatom species
- 2014
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Ingår i: Current Science. - 0011-3891. ; 106:6, s. 867-870
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Tidskriftsartikel (refereegranskat)abstract
- Phytoplankton are key components in primary production and their growth is determined mainly by the availability of nitrogen-nutrients in the ocean. The paradigm that phytoplankton prefer ammonium over nitrate when both substrates are present has been tested using N-15-labelled tracers on cultured diatoms and dinoflagellates isolated from two widespread geographical areas - the Baltic Sea and the Arabian Sea. We found contrary to the paradigm that both taxa preferred nitrate over ammonium and a significant within-species variation in N assimilation. Carbon uptake rates in the same experiments were estimated using C-13-labelled tracer.
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| 25. |
- Singh, Navinder
(författare)
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Forage and security trade-offs by markhor Capra falconeri mothers
- 2016
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Ingår i: Current Science. - 0011-3891. ; 110, s. 1559-1564
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Tidskriftsartikel (refereegranskat)abstract
- Food acquisition and security from predators are primary determinants of habitat use in ungulates. There is usually a trade-off in the response of animals to these two factors, influenced by the individual's reproductive state. Females with vulnerable offspring, after parturition, are expected to compromise food acquisition for security. In temperate species such as the markhor Capra falconeri, however, the females give birth at a time when nutritious forage begins to become available after the long lean period of winter. The need to access quality forage in spring should, therefore, be significant even for new mothers, making the issue of female habitat choice particularly interesting and important to understand. We assessed habitat use patterns of the Pirpanjal markhor during the winter and parturition periods, to examine the response of markhor females to contrasting pressures of forage acquisition and neonate security. Markhor were observed during morning and evening hours along trails and vantage points in the Limber Wildlife Sanctuary, western Himalaya, India. Vegetation abundance and quality were assessed. Principal Components Analyses revealed that during winter, as expected, access to forage was the primary factor influencing habitat choice by female markhor. Following parturition, however, despite the low availability of quality forage throughout the preceding winter, markhor mothers predominantly used secure areas with steep slopes closer to cliffs, even though they were poorer in forage availability. Our results underscore the importance of neonate security in determining habitat use of markhor and the causes of low productivity of this population.
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| 26. |
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| 27. |
- Vanitha, JD, et al.
(författare)
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Identification of a group of nontuberculous mycobacteria isolated from the South Indian BCG trial area by HPLC
- 2002
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Ingår i: Current Science. - 0011-3891. ; 82:2, s. 189-191
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-five isolates of nontuberculous mycobacteria isolated from the South Indian BCG trial area were analysed by high performance liquid chromatography (HPLC) for mycolic acid pattern. The chromatograms differentiated the isolates into four species, namely M. terrae complex, M. intracellulare, M. parafortuitum and M. fortuitum. Three strains were unidentified, one of which did not show any mycolic acid peaks. All isolates had been identified as M. diernhoferi by biochemical methods in a previous study. Nineteen of the isolates were analysed by gas chromatography-mass spectrometry (GC-MS) for the presence of tuberculostearic acid, 2-eicosanol and mycolic acid cleavage products, and were classified as nonchromogens or rapidly growing mycobacteria. The results show that HPLC can discriminate the described mycobacterial species better than biochemical methods and GC-MS.
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