307 research outputs found

    Use of Electronic Information Resources at College libraries in Bangalore, India: A Study of College Learners

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    This research article investigates the accessibility and usage of electronic resources among College libraries in Bangalore, Karnataka, India. In India, most of the institutions initiated electronic information resources in library services. Primary data were collected from four selected college libraries through a structured questionnaire method. Secondary data were collected from various national and international journals, various university libraries, books, magazines, newspapers, reports, etc. Besides, the websites and internet services of the institutions were also used for the purpose of secondary data collection. The result shows that the various e-resources, CD-ROM, e-newspaper, online database, full-text database, e-journal and e-books considered as the most importance e-resources by the respondents and 52.41% of the respondents very much satisfied with e-thesis and dissertation

    Distribution of hydro-biological parameters in coastal waters off Rushikulya Estuary, East Coast of India: A premonsoon case study

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    The hydro-biological parameters of coastal waters off Rushikulya estuary was investigated during premonsoon 2011. Important hydro-biological parameters such as water temperature, salinity, pH, DO, NO2, NO3, NH4, PO4, SiO4, TSM, Chl-α, phytoplankton and zooplankton were measured during the present study. Temperature established a strong positive correlation with salinity and pH during the present study. Chl-α found in positive relation with NO3, SiO4 and TSM. Analysis of variance revealed significant monthly variation in pH, salinity and TSM. Significant station wise variation was observed in DO and most of the nutrients i.e., NO3, NH4, PO4, SiO4. A total of 119 species of phytoplankton were identified of which 84 species are of diatoms, 22 species of dinoflagellates, 7 species of green algae, 5 species of cyanobacteria (blue green algae) and 1 species of cocolithophore. Phytoplankton abundance varied between 25543 (Nos. L-1) and 36309 (Nos. L-1). Diatoms dominated the phytoplankton community followed by dinoflagellates in all the months. Diatoms contributed to 82-89 of the total phytoplankton population density whereas dinoflagellates contributed to 6-12. The regression between Chl-α and phytoplankton abundance resulted with weak relation (R2 = 0.042). Zooplankton fauna composed of 134 species of holoplankton and 20 types of meroplankton were encountered during the study period. Zooplankton population dominated by copepod during all months and accounted for 74 to 85 to the total zooplankton. The population density ranged from 6959 to 35869 Nos./10 m3. Analysis of variance explained no significant variation in total zooplankton abundance and also for different groups of zooplankton

    An off-board quantum point contact as a sensitive detector of cantilever motion

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    Recent advances in the fabrication of microelectromechanical systems (MEMS) and their evolution into nanoelectromechanical systems (NEMS) have allowed researchers to measure extremely small forces, masses, and displacements. In particular, researchers have developed position transducers with resolution approaching the uncertainty limit set by quantum mechanics. The achievement of such resolution has implications not only for the detection of quantum behavior in mechanical systems, but also for a variety of other precision experiments including the bounding of deviations from Newtonian gravity at short distances and the measurement of single spins. Here we demonstrate the use of a quantum point contact (QPC) as a sensitive displacement detector capable of sensing the low-temperature thermal motion of a nearby micromechanical cantilever. Advantages of this approach include versatility due to its off-board design, compatibility with nanoscale oscillators, and, with further development, the potential to achieve quantum limited displacement detection.Comment: 5 pages, 5 figure

    Resolved Sideband Cooling of a Micromechanical Oscillator

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    Micro- and nanoscale opto-mechanical systems provide radiation pressure coupling of optical and mechanical degree of freedom and are actively pursued for their ability to explore quantum mechanical phenomena of macroscopic objects. Many of these investigations require preparation of the mechanical system in or close to its quantum ground state. Remarkable progress in ground state cooling has been achieved for trapped ions and atoms confined in optical lattices. Imperative to this progress has been the technique of resolved sideband cooling, which allows overcoming the inherent temperature limit of Doppler cooling and necessitates a harmonic trapping frequency which exceeds the atomic species' transition rate. The recent advent of cavity back-action cooling of mechanical oscillators by radiation pressure has followed a similar path with Doppler-type cooling being demonstrated, but lacking inherently the ability to attain ground state cooling as recently predicted. Here we demonstrate for the first time resolved sideband cooling of a mechanical oscillator. By pumping the first lower sideband of an optical microcavity, whose decay rate is more than twenty times smaller than the eigen-frequency of the associated mechanical oscillator, cooling rates above 1.5 MHz are attained. Direct spectroscopy of the motional sidebands reveals 40-fold suppression of motional increasing processes, which could enable reaching phonon occupancies well below unity (<0.03). Elemental demonstration of resolved sideband cooling as reported here should find widespread use in opto-mechanical cooling experiments. Apart from ground state cooling, this regime allows realization of motion measurement with an accuracy exceeding the standard quantum limit.Comment: 13 pages, 5 figure

    Minimization of phonon-tunneling dissipation in mechanical resonators

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    Micro- and nanoscale mechanical resonators have recently emerged as ubiquitous devices for use in advanced technological applications, for example in mobile communications and inertial sensors, and as novel tools for fundamental scientific endeavors. Their performance is in many cases limited by the deleterious effects of mechanical damping. Here, we report a significant advancement towards understanding and controlling support-induced losses in generic mechanical resonators. We begin by introducing an efficient numerical solver, based on the "phonon-tunneling" approach, capable of predicting the design-limited damping of high-quality mechanical resonators. Further, through careful device engineering, we isolate support-induced losses and perform the first rigorous experimental test of the strong geometric dependence of this loss mechanism. Our results are in excellent agreement with theory, demonstrating the predictive power of our approach. In combination with recent progress on complementary dissipation mechanisms, our phonon-tunneling solver represents a major step towards accurate prediction of the mechanical quality factor.Comment: 12 pages, 4 figure

    Zbtb46 expression distinguishes classical dendritic cells and their committed progenitors from other immune lineages

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    Distinguishing dendritic cells (DCs) from other cells of the mononuclear phagocyte system is complicated by the shared expression of cell surface markers such as CD11c. In this study, we identified Zbtb46 (BTBD4) as a transcription factor selectively expressed by classical DCs (cDCs) and their committed progenitors but not by plasmacytoid DCs (pDCs), monocytes, macrophages, or other lymphoid or myeloid lineages. Using homologous recombination, we replaced the first coding exon of Zbtb46 with GFP to inactivate the locus while allowing detection of Zbtb46 expression. GFP expression in Zbtb46(gfp/+) mice recapitulated the cDC-specific expression of the native locus, being restricted to cDC precursors (pre-cDCs) and lymphoid organ- and tissue-resident cDCs. GFP(+) pre-cDCs had restricted developmental potential, generating cDCs but not pDCs, monocytes, or macrophages. Outside the immune system, Zbtb46 was expressed in committed erythroid progenitors and endothelial cell populations. Zbtb46 overexpression in bone marrow progenitor cells inhibited granulocyte potential and promoted cDC development, and although cDCs developed in Zbtb46(gfp/gfp) (Zbtb46 deficient) mice, they maintained expression of granulocyte colony-stimulating factor and leukemia inhibitory factor receptors, which are normally down-regulated in cDCs. Thus, Zbtb46 may help enforce cDC identity by restricting responsiveness to non-DC growth factors and may serve as a useful marker to identify rare cDC progenitors and distinguish between cDCs and other mononuclear phagocyte lineages

    Peripheral CD103+ dendritic cells form a unified subset developmentally related to CD8α+ conventional dendritic cells

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    Although CD103-expressing dendritic cells (DCs) are widely present in nonlymphoid tissues, the transcription factors controlling their development and their relationship to other DC subsets remain unclear. Mice lacking the transcription factor Batf3 have a defect in the development of CD8α(+) conventional DCs (cDCs) within lymphoid tissues. We demonstrate that Batf3(−/−) mice also lack CD103(+)CD11b(−) DCs in the lung, intestine, mesenteric lymph nodes (MLNs), dermis, and skin-draining lymph nodes. Notably, Batf3(−/−) mice displayed reduced priming of CD8 T cells after pulmonary Sendai virus infection, with increased pulmonary inflammation. In the MLNs and intestine, Batf3 deficiency resulted in the specific lack of CD103(+)CD11b(−) DCs, with the population of CD103(+)CD11b(+) DCs remaining intact. Batf3(−/−) mice showed no evidence of spontaneous gastrointestinal inflammation and had a normal contact hypersensitivity (CHS) response, despite previous suggestions that CD103(+) DCs were required for immune homeostasis in the gut and CHS. The relationship between CD8α(+) cDCs and nonlymphoid CD103(+) DCs implied by their shared dependence on Batf3 was further supported by similar patterns of gene expression and their shared developmental dependence on the transcription factor Irf8. These data provide evidence for a developmental relationship between lymphoid organ–resident CD8α(+) cDCs and nonlymphoid CD103(+) DCs

    Demonstration of an ultracold micro-optomechanical oscillator in a cryogenic cavity

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    Preparing and manipulating quantum states of mechanical resonators is a highly interdisciplinary undertaking that now receives enormous interest for its far-reaching potential in fundamental and applied science. Up to now, only nanoscale mechanical devices achieved operation close to the quantum regime. We report a new micro-optomechanical resonator that is laser cooled to a level of 30 thermal quanta. This is equivalent to the best nanomechanical devices, however, with a mass more than four orders of magnitude larger (43 ng versus 1 pg) and at more than two orders of magnitude higher environment temperature (5 K versus 30 mK). Despite the large laser-added cooling factor of 4,000 and the cryogenic environment, our cooling performance is not limited by residual absorption effects. These results pave the way for the preparation of 100-um scale objects in the quantum regime. Possible applications range from quantum-limited optomechanical sensing devices to macroscopic tests of quantum physics.Comment: Published versio

    Search for CP violation in D+→ϕπ+ and D+s→K0Sπ+ decays

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    A search for CP violation in D + → ϕπ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb−1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K − K + mass within 20 MeV/c 2 of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D + → K − K + π + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+s→K0Sπ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%

    Antioxidant potential of bitter cumin (Centratherum anthelminticum (L.) Kuntze) seeds in in vitro models

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    <p>Abstract</p> <p>Background</p> <p>Bitter cumin (<it>Centratherum anthelminticum </it>(L.) Kuntze), is a medicinally important plant. Earlier, we have reported phenolic compounds, antioxidant, and anti-hyperglycemic, antimicrobial activity of bitter cumin. In this study we have further characterized the antioxidative activity of bitter cumin extracts in various in vitro models.</p> <p>Methods</p> <p>Bitter cumin seeds were extracted with a combination of acetone, methanol and water. The antioxidant activity of bitter cumin extracts were characterized in various <it>in vitro </it>model systems such as DPPH radical, ABTS radical scavenging, reducing power, oxidation of liposomes and oxidative damage to DNA.</p> <p>Results</p> <p>The phenolic extracts of bitter cumin at microgram concentration showed significant scavenging of DPPH and ABTS radicals, reduced phosphomolybdenum (Mo(VI) to Mo(V)), ferricyanide Fe(III) to Fe(II), inhibited liposomes oxidation and hydroxyl radical induced damage to prokaryotic genomic DNA. The results showed a direct correlation between phenolic acid content and antioxidant activity.</p> <p>Conclusion</p> <p>Bitter cumin is a good source of natural antioxidants.</p
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