243 research outputs found

    ECOLOGICAL STATUS AND IMPACT OF DISTURBANCE IN AN ALPINE PASTURE OF GARHWAL HIMALAYA, INDIA

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    The alpine area in Garhwal Himalaya is highly fragile and is known for its beautiful flora and fauna. The study area was located just below the Gangotri glacier which is the origin of Bhagirathi, a holy river of India. Pilgrimage, tourism, adventure activities and mules are the factors responsible for causing disturbance in this area. There is a remarkable variation in the values of diversity, species richness, dominance, density IVI and biomass production at Bhojbasa Protected (BP) and Bhojbasa Disturbed (BD) sites. The value of liveshoot biomass was highest in August (444 g m-2 on BP and 80 g m-2 on BD sites). Belowground biomass was also recorded highest for BP site and lowest for BD site. The ANP value at BP site was 363 g m-2 y-1 and 26 g m-2 y-1 at BD site.This area has shown decrease in diversity and productivity, and heavy soil erosion that indicate the consequence of increasing human activities due to pilgrimage, tourism and camping and frequent movement of mules carrying goods. Therefore, this area requires strict measures for biodiversity conservation and disaster mitigation

    Pattern Programmable Kernel Filter for Bot Detection

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    Bots earn their unique name as they perform a wide variety of automated task. These tasks include stealing sensitive user information. Detection of bots using solutions such as behavioral correlation of flow records, group activity in DNS traffic, observing the periodic repeatability in communication, etc., lead to monitoring the network traffic and then classifying them as Bot or normal traffic. Other solutions for Bot detection include kernel level key stroke verification, system call initialization, IP black listing, etc. In the first two solutions there is no assurance that the packet carrying user information is prevented from being sent to the attacker and the latter suffers from the problem of IP spoofing. This motivated us to think of a solution that would filter out the malicious packets before being put onto the network. To come out with such a solution, a real time bot attack was generated with SpyEye Exploit kit and traffic characteristics were analyzed. The analysis revealed the existence of a unique repeated communication between the Zombie machine and the botmaster. This motivated us to propose, a Pattern Programmable Kernel Filter (PPKF) for filtering out the malicious packets generated by bots. PPKF was developed using the windows filtering platform (WFP) filter engine. PPKF was programmed to filter out the packets with unique pattern which were observed from the bot attack experiments. Further PPKF was found to completely suppress the flow of packets having the programmed uniqueness in them thus preventing the functioning of bots in terms of user information being sent to the Botmaster.Defence Science Journal, 2012, 62(1), pp.174-179, DOI:http://dx.doi.org/10.14429/dsj.62.142

    Facile synthesis and photoluminescence spectroscopy of 3D-triangular GaN nano prism islands

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    We report a strategy for fabrication of 3D triangular GaN nano prism islands (TGNPI) grown on Ga/Si(553) substrate at tow temperature by N-2(+) ions implantation using a sputtering gun technique. The annealing of Ga/Si(553) (600 degrees C) followed by nitridation (2 key) shows the formation of high quality GaN TGNPI cross-section. TGNPI morphology has been confirmed by atomic force microscopy. Furthermore, these nano prism islands exhibit prominent ultra-violet luminescence peaking at 366 nm upon 325 nm excitation wavelength along with a low intensity yellow luminescence broad peak at 545 nm which characterizes low defects density TGNPI. Furthermore, the time-resolved spectroscopy of luminescent TGNPI in nanoseconds holds promise for its futuristic application in next generation UV-based sensors as well as many portable optoelectronic devices

    Structural and magnetic phenomena in Ni53Mn25Al22 thin film prepared by rf magnetron sputtering

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    Magnetic and structural properties of Ni–Mn–Al thin films are investigated. It is demonstrated that the annealed film shows L21 phase at room temperature. Magnetometry measurements reveal that the annealed film is ferromagnetic and a first order transition in magnetization versus temperature measurement confirms that the martensite to austenite transition occurs around room temperature. Transmission electron microscopy measurements confirm that this structural change occurs just below room temperature. The splitting of Mn 2p3/2 level in x-ray photoelectron spectroscopy core level spectra of the annealed Ni–Mn–Al film, confirms that the origin of magnetism is definitely correlated with the local magnetic moment at the Mn atoms

    Anomalous heat capacity and X-ray photoelectron spectroscopy of Superconducting FeSe1/2Te1/2

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    The bulk polycrystalline sample FeSe1/2Te1/2 is synthesized by solid state reaction route in an evacuated sealed quartz tube at 750 oC. The presence of superconductivity is confirmed through magnetization/thermoelectric/resistivity studies. It is found that the superconducting transition temperature (Tc) is around 12 K. Heat capacity (Cp) of superconducting FeSe1-xTex exhibited a hump near Tc, instead of well defined Lambda transition. X-ray Photo electron spectroscopy (XPS) studies revealed well defined positions for divalent Fe, Se and Te but with sufficient hybridization of Fe (2p) and Se/Te (3d) core levels. In particular divalent Fe is shifted to higher BE (binding energy) and Se and Te to lower. The situation is similar to that as observed earlier for famous Cu based HTSc (High Tc superconductors), where Cu (3d) orbital hybridizes with O (2p). We also found the satellite peak of Fe at 712.00 eV, which is attributed to charge carrier localization induced by Fe at 2c site.Comment: 12 pages text + Figs contact Author-VPS Awana (www.freewebs.com/vpsawana

    Mapping QTLs Controlling Flowering Time, Plant Height, Panicle length and Grain Mass in Pearl Millet [Pennisetum glaucum (L.) R. Br.]

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    Pearl millet is an important cereal of arid- and semi-arid regions, and can endure dry conditions but experiences drought stress during post-flowering growth. Exploiting the bold seeded semi-dwarf early flowering genotypes in pearl millet is a key breeding strategy to enhance yield and for adequate food in resource-poor zones. Genetic variation for agronomic traits of pearl millet inbreds can be used to dissect complex traits through QTL mapping. Quantitative trait locus (QTL) mapping for 50% flowering time, plant height, panicle length, and grain mass (self and open pollinated seeds) was performed in recombinant inbred line (RIL) population, ICMB 841-P3 ? 863B-P2. Correlations between traits were also performed and significantly negative association between plant height and TGM was observed. High heritabilities (>0.6) were recorded for all traits. A total of 50 QTLs that affected above traits were detected. Six putative QTLs for 50% flowering time were identified on five chromosomes. One QTL on LG3 were common between flowering time and plant height. Three major QTLs for panicle length, one each on LG1, LG2 and LG6B were detected.The major QTL for TGM_self on LG 6B had a partial R2 of 23.8% and 0.8 additive effects.The total phenotypic variance for 50% FT, TGM_self, and panicle length was 23.2% (LOD- 56.28), 22.3% (LOD- 5.96) and 59.4% (LOD- 52), respectively.A total of 21 digenic interactions were demonstrated for 50%FT (R2=18%-40%) and PL (R2publishersversionPeer reviewe

    Performance analysis of anomalous photocatalytic activity of Cr-doped TiO2 nanoparticles [Cr(x)TiO2(1-x)]

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    We report the synthesis and characterisation of pristine and chromium (Cr) metal ion-doped titanium dioxide nanoparticles [Cr(x)TiO2(1-x)] to study the anomalous effect of Cr doping on the photocatalytic property of TiO2. The presence of dopants generates more number of recombination pairs and increases surface coverage sites which decreases photocatalytic activity. We study the structural morphology of the synthesised Cr(x)TiO2(1-x) samples using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy analysis. The effect of Cr3+ ions on the optical properties of TiO2 has been studied using various imaging and spectroscopic techniques. Further, the effect of doping of Cr on the photocatalytic activity of TiO2 has been analysed in detail. The concentration of Cr in TiO2 has been chosen as 0, 1, 5 and 10% by weight. It has been observed that the pristine TiO2 exhibits better photocatalytic activity as compared to Cr-doped TiO2 irrespective of the Cr concentration. This can be attributed to the fact that due to Cr doping in TiO2, the number of available adsorption sites for malachite green reduces which degrades its photocatalytic activity. It is also confirmed by photoluminescence (PL) and time-resolved photoluminescence spectroscopy. PL intensity increases, and lifetime decreases with increase in doping concentration. Radiative recombination of electron and hole pairs of Cr3+ in TiO2 degrades its photocatalytic activity. The degradation efficiency is found to be 96% in the case of pristine TiO2 which reduces to 12% when doped with x = 10% concentration of chromium. Therefore, it is observed that in comparison with Cr-doped TiO2, pristine TiO2 exhibits an improved photocatalytic activity which shows the anomalous effect of Cr doping on the photocatalytic property of TiO2

    Comparison of pharmacokinetic parameters of oxytetracycline following single intravenous administration in goat, sheep and cattle calf

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    The study was conducted to evaluate pharmacokinetics of oxytetracycline following single intravenous administration in goat sheep and cattle calves, and calculate the suitable dosages regimens. For this 15 animals were used 5 each of female goats, male sheep and male cattle calves in each species. Oxytetracycline hydrochloride solution was injected as a single dose (5 mg/kg) intravenous (i.v.) bolus administration. The analysis of plasma samples for oxytetracycline was done by HPLC. The OTC maintained its minimum ETC of 0.5 µg/ml up to 480 min in goat and sheep and 720 min in cattle calves after 5mg/kg body weight through intravenous administration, respectively. The pharmacokinetic parameters obtained in this study indicates that the OTC have wide distribution and longer residential time in body and maintained the therapeutic concentration in body

    Mapping Quantitative Trait Loci Controlling High Iron and Zinc Content in Self and Open Pollinated Grains of Pearl Millet [Pennisetum glaucum (L.) R. Br.]

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    Pearl millet is a multipurpose grain/fodder crop of the semi-arid tropics, feeding many of the world’s poorest and most undernourished people. Genetic variation among adapted pearl millet inbreds and hybrids suggests it will be possible to improve grain micronutrient concentrations by selective breeding. Using 305 loci, a linkage map was constructed to map QTLs for grain [Fe] and [Zn] using replicated samples of 106 pearl millet RILs (F6) derived from ICMB 841-P3 × 863B-P2. The grains of the RIL population were evaluated for Fe and Zn concentration using atomic absorption spectrophotometer. Grain mineral concentrations ranged from 28.4-124.0 ppm for Fe and 28.7-119.8 ppm for Zn. Similarly,grain Fe and Zn in open pollinated seeds ranged between 22.4-77.4 and 21.9-73.7 ppm, respectively. Mapping with 305 (96 SSRs; 208 DArT) markers detected seven linkage groups covering 1749 cM (Haldane) with an average intermarker distance of 5.73 cM. On the basis of two environment phenotypic data, two co-localized QTLs for Fe and Zn density on LG 3 were identified by composite interval mapping (CIM). Fe QTL explained 19% phenotypic variation, whereas the Zn QTL explained 36% phenotypic variation. Likewise for open pollinated seeds, the QTL analysis led to identification of two QTLs for grain Fe density on LG 3 and 5, and two QTLs for grain Zn density on LG 3 and 7. The total phenotypic variance for Fe and Zn QTLs in open pollinated seeds was 16% and 42%, respectively. Analysis of QTL × QTL and QTL × QTL× environment interactions indicated no major epistasis

    High yield synthesis of electrolyte heating assisted electrochemically exfoliated graphene for electromagnetic interference shielding applications

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    Herein, we demonstrate a facile one pot synthesis of graphene nanosheets by electrochemical exfoliation of graphite. In the present study, we report a significant increase in the yield of graphene by electrolyte heating assisted electrochemical exfoliation method. The obtained results of heating assisted electrochemically exfoliated graphene (utilizing H2SO4 + KOH + DW) synthesis clearly exhibit that the yield increases similar to 4.5 times i.e. from similar to 17% (room temperature) to similar to 77% (at 80 degrees C). A plausible mechanism for the enhanced yield based on lattice expansion and vibration of intercalated ions has been put forward and discussed in details. The quality of graphene was examined by Raman, XPS, FTIR, AFM, SEM, TEM/HRTEM and TGA techniques. The Raman as well as morphogenesis results confirm the quality of the graphene nanosheets. We have used this graphene as electromagnetic interference shielding material where a comparatively large quantity of graphene is required. This graphene exhibits enhanced shielding effectiveness (46 dB at 1 mm thickness of stacked graphene sheets in frequency region 12.4 to 18 GHz) as compared to conventional electromagnetic interference shielding materials, which is greater than the recommended limit (similar to 30 dB) for techno-commercial applications. Thus the present work is suggestive for future studies on enhancement of yield of high quality graphene by proposed method and the use of synthesized graphene in electromagnetic interference shielding and other possible applications
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