526 research outputs found

    ICT-based reforms in local government decision-making in the gram panchayats of Kerala

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    The beneficial impact of computerisation can be felt in all elements that contribute to decision-making in panchayats in the state of Kerala. However, even though computerisation is bringing about immense improvements compared to traditional administrative practices, but scope still remains for further improvement. Instead of the 'as it is' computerisation that is mostly carried out a process based approach is needed

    Psychophysical and electrophysiological investigations into the mechanisms supporting everyday communication

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    Thesis (Ph.D.)--Boston UniversityHumans solve the so-called "cocktail party problem" with relative ease, and are generally able to selectively direct their attention to process and recall acoustic information from one sound source in the presence of other irrelevant stimuli that are competing for cognitive resources. This ability depends on a variety of factors, including volitional control of selective attention, the ability to store information in memory for recall at a later time, and the ability to integrate information across multiple sensory modalities. Here, psychophysical and electroencephalography (EEG) experiments were conducted to study these three factors. The effects of selective attention on cortical and subcortical structures were examined using EEG recorded during a dichotic listening task. Cortical potentials showed robust effects of attention (demonstrated by the ability to classify responses to attended and ignored speech based on short segments of EEG responses); however, potentials originating in the brainstem did not, even though stimuli were engineered to maximize the separability of the neural representation of the competing sources in the auditory periphery and thus the possibility of seeing attention-specific modulation of subcortical responses. In another study, the relationship between object formation and memory processing was explored in a psychophysical experiment examining how sequences of nonverbal auditory stimuli are stored and recalled from short-term memory. The results of this study support the notion that auditory short-term memory, like visual short-term memory, can be explained in terms of object formation. In particular, short-term memory performance is affected by stream formation and the perceptual costs involved in switching attention between multiple streams. Finally, effects of audiovisual integration were studied in a psychophysical experiment using complex speech-like stimuli (zebra finch songs). Results show visual cues improve performance differently depending on whether target identification is limited by energetic masking or whether it is limited by object formation difficulties and uncertainty about when a target occurs. Together, these studies support the idea that everyday communication depends on an interplay of many mechanisms including attention, memory, and multisensory integration, each of which is influenced by perceptual organization

    Benzimidazole-modified polyaniline micro-shells for electrochemical detection of cadmium in aqueous solution

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    Benzimidazole-functionalized polyaniline (BMPANI) was synthesized by interfacial poly­merization technique and used for electrochemical sensing of cadmium ions in an aqueous solution. The material was characterized for its structural and morphological features using Fourier-transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The BMPANI has a micro-shell structure produced from the self-assembly of the monomer units in solution before the polymerization reaction. The material was trialed for cadmium ion sensing using a BMPANI-modified carbon paste electrode (BMPANI-CPE). Electrochemical techniques, i.e., cyclic voltammetry (CV) and differential pulse anodic stripping voltammetry (DPASV), were performed to assess the sensing characteristics of the material. Various electrode preparation parameters, i.e., deposition potential, pH of deposition solution, and thickness of the active layer, were optimized to achieve the highest level of sensitivity. The selectivity towards cadmium ions, interference from other ions, as well as stability and reusability of the BMPANI-CPE, were also examined and found to be satisfactory

    Photoemission with virtual photons

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    In this manuscript, we demonstrate a novel technique to probe the electronic structure of the top-most atomic layer of a solid using the virtual photon exchange between a positron and a valence band electron. This process, termed Auger-mediated positron sticking, is initiated by the coupling of the energy and momentum associated with the trapping of a positron in an image-potential-induced surface state to an electron in the material. We have used this quantum sticking of low-energy positrons to probe the valence band density of states of single-layer graphene and copper. The measured positron-induced electron spectra were successfully reproduced using a model which is principally composed of the valence band density of states. Our results demonstrate that Auger-mediated positron sticking is a top-most atomic layer selective probe of the electronic structure of fragile two dimensional surfaces which can complement existing photoemission spectroscopy techniques. The exceptional surface selectivity of Auger-mediated positron sticking arises because the excitation depth is limited to the Thomas-Fermi screening length. Finally, the analysis of the Cu spectrum in terms of the partial density of states reveals matrix element effects that suppress the contribution of valence 3d electrons relative to the 4s and 4p electrons

    Catalytic and Electrochemical Sensing Studies of Silver/Poly(1-Naphthylamine) Nanocomposites Synthesised by a Green Method

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    Metal nanoparticles incorporated conducting polymer nanocomposites have outstanding properties and potential applications in various fields and significant research has been carried out over the last two decades for the development of efficient methods for their synthesis. The current study describes a microwave-assisted, rapid, and environmentally friendly method for depositing silver nanoparticles (AgNPs) over poly(1-naphthylamine) (PNA) using clammy cherry (Cordia Obliqua willd) extract as a reductant to create silver/nanocomposites (Gr-Ag/PNA) with varying silver contents. Thermal stability and charge transfer kinetics of PNA was significantly improved upon introducing AgNPs, as evidenced by the thermogravimetric analysis and electrochemical investigations, respectively. All prepared Gr-Ag/PNA nanocomposites could show improved catalytic activity towards the borohydride-aided reduction of 4-nitrophenol (4-NP) and the pseudo-first-order rate constants showed a direct relationship with the percent of silver incorporated over PNA. Additionally, for the first time, the Gr-Ag/PNA modified carbon paste electrode (Gr-Ag/PNA/CPE) was utilized to validate its usefulness and applicability in the electrocatalytic reduction of 4-NP. A low-cost enzymeless voltammetric 4-NP sensor based on Gr-Ag/PNA/CPE was fabricated and it showed excellent selectivity for 4-NP, as well as a strong linear response over a wide range of 4-NP concentrations (30-1000 M) and a detection limit of 6.25 M
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