561 research outputs found

    Superpolynomial lower bounds for general homogeneous depth 4 arithmetic circuits

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    In this paper, we prove superpolynomial lower bounds for the class of homogeneous depth 4 arithmetic circuits. We give an explicit polynomial in VNP of degree nn in n2n^2 variables such that any homogeneous depth 4 arithmetic circuit computing it must have size nΩ(loglogn)n^{\Omega(\log \log n)}. Our results extend the works of Nisan-Wigderson [NW95] (which showed superpolynomial lower bounds for homogeneous depth 3 circuits), Gupta-Kamath-Kayal-Saptharishi and Kayal-Saha-Saptharishi [GKKS13, KSS13] (which showed superpolynomial lower bounds for homogeneous depth 4 circuits with bounded bottom fan-in), Kumar-Saraf [KS13a] (which showed superpolynomial lower bounds for homogeneous depth 4 circuits with bounded top fan-in) and Raz-Yehudayoff and Fournier-Limaye-Malod-Srinivasan [RY08, FLMS13] (which showed superpolynomial lower bounds for multilinear depth 4 circuits). Several of these results in fact showed exponential lower bounds. The main ingredient in our proof is a new complexity measure of {\it bounded support} shifted partial derivatives. This measure allows us to prove exponential lower bounds for homogeneous depth 4 circuits where all the monomials computed at the bottom layer have {\it bounded support} (but possibly unbounded degree/fan-in), strengthening the results of Gupta et al and Kayal et al [GKKS13, KSS13]. This new lower bound combined with a careful "random restriction" procedure (that transforms general depth 4 homogeneous circuits to depth 4 circuits with bounded support) gives us our final result

    Emerging power in industrialization: empowering India through entrepreneurship

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    The 'soft power' can be brought forward and achieved for any developing country through softer means. Advertising (both direct and indirect approach) is a powerful tool for disseminating information to various stakeholders concerning the MSME sector. To introspect the potentiality of India's MSME's emerging power, the researchers attempted to answer the different components that shaped Indian industrialization over the years and also analyzed the direct and indirect audio-visual advertisements created on MSMEs to encourage entrepreneurial activities throughout the nation. The observation indicates that direct and indirect advertisements that promote and encourage the growth of entrepreneurship have their advantages and disadvantages; however, direct advertisements are proven to be preferred over indirect advertisements, while the reason behind it can be the dilution of concept or the prominence of commercialization

    Synthesis, characterization of Silica Obtained from Rice Husk and Determination its Silica Content by Modified Volumetric Method

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    The objective of the work was to develop pure silica with high surface area from rice husk by chemical and heat treatment. The silica samples were characterized in terms of chemical composition, particle size distribution, morphology and surface area. The amount of silica was determined by a modified volumetric method. The trace impurities in silica were quantitatively determined by inductive coupled plasma atomic emission spectroscopy (ICP-AES). A 99 % silica powder with surface area 282 m2/gm could be produced by chemical and heat treatment at 1000 ºC for 2 h

    Quantifying uncertainty in the measurement of arsenic in suspended particulate matter by Atomic Absorption Spectrometry with hydride generator

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    Arsenic is the toxic element, which creates several problems in human being specially when inhaled through air. So the accurate and precise measurement of arsenic in suspended particulate matter (SPM) is of prime importance as it gives information about the level of toxicity in the environment, and preventive measures could be taken in the effective areas. Quality assurance is equally important in the measurement of arsenic in SPM samples before making any decision. The quality and reliability of the data of such volatile elements depends upon the measurement of uncertainty of each step involved from sampling to analysis. The analytical results quantifying uncertainty gives a measure of the confidence level of the concerned laboratory. So the main objective of this study was to determine arsenic content in SPM samples with uncertainty budget and to find out various potential sources of uncertainty, which affects the results. Keeping these facts, we have selected seven diverse sites of Delhi (National Capital of India) for quantification of arsenic content in SPM samples with uncertainty budget following sampling by HVS to analysis by Atomic Absorption Spectrometer-Hydride Generator (AAS-HG). In the measurement of arsenic in SPM samples so many steps are involved from sampling to final result and we have considered various potential sources of uncertainties. The calculation of uncertainty is based on ISO/IEC17025: 2005 document and EURACHEM guideline. It has been found that the final results mostly depend on the uncertainty in measurement mainly due to repeatability, final volume prepared for analysis, weighing balance and sampling by HVS. After the analysis of data of seven diverse sites of Delhi, it has been concluded that during the period from 31st Jan. 2008 to 7th Feb. 2008 the arsenic concentration varies from 1.44 ± 0.25 to 5.58 ± 0.55 ng/m3 with 95% confidence level (k = 2)

    Multi-epoch hard X-ray view of Compton-thick AGN Circinus Galaxy

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    The circumnuclear material around Active Galactic Nuclei (AGN) is one of the essential components of the obscuration-based unification model. However, our understanding of the circumnuclear material in terms of its geometrical shape, structure and its dependence on accretion rate is still debated. In this paper, we present the multi-epoch broadband X-ray spectral modelling of a nearby Compton-thick AGN in Circinus galaxy. We utilise all the available hard X-ray (>10> 10 keV) observations taken from different telescopes, i.e.,i.e., BeppoSAXBeppoSAX, SuzakuSuzaku, NuSTARNuSTAR and AstroSatAstroSat, at ten different epochs across 2222 years from 19981998 to 20202020. The 3.0793.0-79 keV broadband X-ray spectral modelling using physically-motivated models, namely MYTORUS, BORUS02 and UXCLUMPY, infers the presence of a torus with a low covering factor of 0.280.28, an inclination angle of 7777^{\circ} - 8181^{\circ} and Compton-thick line-of-sight column densities (NH,LOS=4.13  9.26 × 1024N_{\rm H,LOS} = 4.13~-~9.26~\times~10^{24} cm2^{-2}) in all the epochs. The joint multi-epoch spectral modelling suggests that the overall structure of the torus is likely to remain unchanged. However, we find tentative evidence for the variable line-of-sight column density on timescales ranging from one day to one week to a few years, suggesting a clumpy circumnuclear material located at sub-parsec to tens of parsec scales.Comment: 18 pages, 7 figures, 6 tables, accepted for publication in Monthly Notices of the Royal Astronomical Societ

    Accumulation of Immature Langerhans Cells in Human Lymph Nodes Draining Chronically Inflamed Skin

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    The coordinated migration and maturation of dendritic cells (DCs) such as intraepithelial Langerhans cells (LCs) is considered critical for T cell priming in response to inflammation in the periphery. However, little is known about the role of inflammatory mediators for LC maturation and recruitment to lymph nodes in vivo. Here we show in human dermatopathic lymphadenitis (DL), which features an expanded population of LCs in one draining lymph node associated with inflammatory lesions in its tributary skin area, that the Langerin/CD207+ LCs constitute a predominant population of immature DCs, which express CD1a, and CD68, but not CD83, CD86, and DC–lysosomal-associated membrane protein (LAMP)/CD208. Using LC-type cells generated in vitro in the presence of transforming growth factor (TGF)-β1, we further found that tumor necrosis factor (TNF)-α, as a prototype proinflammatory factor, and a variety of inflammatory stimuli and bacterial products, increase Langerin expression and Langerin dependent Birbeck granules formation in cell which nevertheless lack costimulatory molecules, DC–LAMP/CD208 and potent T cell stimulatory activity but express CCR7 and respond to the lymph node homing chemokines CCL19 and CCL21. This indicates that LC migration and maturation can be independently regulated events. We suggest that during DL, inflammatory stimuli in the skin increase the migration of LCs to the lymph node but without associated maturation. Immature LCs might regulate immune responses during chronic inflammation

    A Method for Amplicon Deep Sequencing of Drug Resistance Genes in Plasmodium falciparum Clinical Isolates from India.

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    A major challenge to global malaria control and elimination is early detection and containment of emerging drug resistance. Next-generation sequencing (NGS) methods provide the resolution, scalability, and sensitivity required for high-throughput surveillance of molecular markers of drug resistance. We have developed an amplicon sequencing method on the Ion Torrent PGM platform for targeted resequencing of a panel of six Plasmodium falciparum genes implicated in resistance to first-line antimalarial therapy, including artemisinin combination therapy, chloroquine, and sulfadoxine-pyrimethamine. The protocol was optimized using 12 geographically diverse P. falciparum reference strains and successfully applied to multiplexed sequencing of 16 clinical isolates from India. The sequencing results from the reference strains showed 100% concordance with previously reported drug resistance-associated mutations. Single-nucleotide polymorphisms (SNPs) in clinical isolates revealed a number of known resistance-associated mutations and other nonsynonymous mutations that have not been implicated in drug resistance. SNP positions containing multiple allelic variants were used to identify three clinical samples containing mixed genotypes indicative of multiclonal infections. The amplicon sequencing protocol has been designed for the benchtop Ion Torrent PGM platform and can be operated with minimal bioinformatics infrastructure, making it ideal for use in countries that are endemic for the disease to facilitate routine large-scale surveillance of the emergence of drug resistance and to ensure continued success of the malaria treatment policy

    6. MEMS based color-VGA micro-projector system

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    This paper presents a complete portable laser-based projection system using twofold of one dimensional magnetic actuated MEMS linear scanning micro-mirrors. Dedicated high speed electronics was developed to drive the MEMS, detect the mirror scanning position at any time and synchronize the two mirrors and the laser pulsation. The achieved projection system head is 4.5 cm3 and is able to project colorful static images and videos (50 fps) with projection size of 50 cm diagonal at 50 cm distance with VGA (640×480 px) resolution
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