957 research outputs found

    Vertical profiles of atmospheric electric parameters close to ground

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    The ion-aerosol balance equations have been solved for different mixing strengths and two types of ionization profile to get vertical profiles of atmospheric electric parameters close to the Earth's surface. The inclusion of surface radioactivity in the model causes the decrease in electric field to be more intense at lower levels than at higher levels, an increase in the asymptotic value of the field, and an increase in the space charge density gradient. When the mixing of atmosphere is very weak, a reverse electrode effect is observed under the condition of enhanced ionization due to trapped radon, with the decrease in ion densities above 1 m. However, with an increase in eddy diffusivity, the positive ion concentration decreases, and the negative ion concentration increases with increasing height above the diffusion layer. Further increase, in eddy diffusivity causes the profiles to become almost similar to those for which the ionization is constant with height. Even with the inclusion of radon radioactivity, relatively higher diffusivity keeps the nature of the profile of the negative ions similar to that for the constant ionization case. On the contrary, there is a drastic change in the profile of positive ions because of the strong downward gradient of positive ions in the diffusion sublayer. The profile of positive ions is more sensitive to the radon radioactivity and that of negative ions to the strength of turbulence. Further, the asymptotic value of aerosol concentration is reached before that of small ions when mixing is very low. Our results are in reasonable agreement with the earlier theoretical and experimental studies

    Projected Changes in Semi Permanent Systems of Indian Summer Monsoon in CORDEX-SA Framework

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    The semi-permanent systems such as Seasonal Heat Low (HL), Monsoon Trough (MT), Tibetan Anticyclone (TA), Tropical Easterly Jet (TEJ) and Low Level Jet (LLJ) or Somali jet are observed over Indian region during Indian summer monsoon season (June through September). These systems play a vital role in defining the strength of the Indian summer monsoon rainfall as a whole. Here we evaluate the ability of Consortium for Small-Scale Modeling (COSMO) regional Climate Model (COSMO-CLM), a high resolution regional climate model within the Coordinated Regional Climate Downscaling Experiment for South Asia (CORDEX-SA) framework, to simulate these systems of Indian summer monsoon. The historical runs of the COSMO-CLM for the period 1951-2000 are analysed. Overall the COSMO-CLM is able to simulate these components reasonably well. Possible changes in the position and the strength of these systems and their role in changing rainfall pattern over India are examined to assess the impact of global warming, under the RCP 4.5 simulations towards the end of the century (2051-2100). The analysis shows that the semi permanent systems may not strengthen in the future as compared to the present climate. The summer monsoon rainfall does not show uniform changes over the region. It is likely to enhance over the southern parts of the country, south of 20?S while it is projected to decrease in the northern parts under the global warming scenario

    Study of extreme point rainfall over flash flood prone regions of the Himalayan foot hills of north India

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    In north India flash flood normally occur in the foothill and sub-montane regions of the Himalayas during the monsoon months due to incidence of heavy fall of rain

    Decolorization of synthetic melanoidins-containing wastewater by a bacterial consortium

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    The presence of melanoidins in molasses wastewater leads to water pollution both due to its dark brown color and its COD contents. In this study, a bacterial consortium isolated from waterfall sediment was tested for its decolorization. The identification of culturable bacteria by 16S rDNA based approach showed that the consortium composed of Klebsiella oxytoca, Serratia mercescens, Citrobacter sp. and unknown bacterium. In the context of academic study, prevention on the difficulties of providing effluent as well as its variations in compositions, several synthetic media prepared with respect to color and COD contents based on analysis of molasses wastewater, i.e., Viandox sauce (13.5% v/v), caramel (30% w/v), beet molasses wastewater (41.5% v/v) and sugarcane molasses wastewater (20% v/v) were used for decolorization using consortium with color removal 9.5, 1.13, 8.02 and 17.5%, respectively, within 2 days. However, Viandox sauce was retained for further study. The effect of initial pH and Viandox concentration on decolorization and growth of bacterial consortium were further determined. The highest decolorization of 18.3% was achieved at pH 4 after 2 day of incubation. Experiments on fresh or used medium and used or fresh bacterial cells, led to conclusion that the limitation of decolorization was due to nutritional deficiency. The effect of aeration on decolorization was also carried out in 2 L laboratory-scale suspended cell bioreactor. The maximum decolorization was 19.3% with aeration at KLa = 2.5836 h-1 (0.1 vvm)

    Robotic ubiquitous cognitive ecology for smart homes

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    Robotic ecologies are networks of heterogeneous robotic devices pervasively embedded in everyday environments, where they cooperate to perform complex tasks. While their potential makes them increasingly popular, one fundamental problem is how to make them both autonomous and adaptive, so as to reduce the amount of preparation, pre-programming and human supervision that they require in real world applications. The project RUBICON develops learning solutions which yield cheaper, adaptive and efficient coordination of robotic ecologies. The approach we pursue builds upon a unique combination of methods from cognitive robotics, machine learning, planning and agent- based control, and wireless sensor networks. This paper illustrates the innovations advanced by RUBICON in each of these fronts before describing how the resulting techniques have been integrated and applied to a smart home scenario. The resulting system is able to provide useful services and pro-actively assist the users in their activities. RUBICON learns through an incremental and progressive approach driven by the feed- back received from its own activities and from the user, while also self-organizing the manner in which it uses available sensors, actuators and other functional components in the process. This paper summarises some of the lessons learned by adopting such an approach and outlines promising directions for future work

    Porto-systemic shunt using adrenal vein as a conduit; an alternative procedure for spleno – renal shunt

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    PubMed ID: 17555599Background. Currently, portal hypertension is still big problem for the patients with serious liver diseases. Variceal bleeding is one of the most important complications of portal hypertension. In case of failure of endoscopic and combined medical treatments, surgical decompressive shunts are required. We emphasized an alternative splenorenal shunt procedure using adrenal vein as a conduit. Case presentation. A 26-year-old male suffered from recurrent variceal bleeding was considered for surgical therapy. Although we planned to perform a distal splenorenal shunt procedure, it was observed to be difficult. Therefore left adrenal vein was used as a conduit between left renal vein and splenic vein after splenic artery was ligated. He did well and was discharged from the hospital on the postoperative day 6. In the follow up period for nine months, endoscopic and ultrasonographic examinations were normal. Conclusion. We concluded that, in case of failure to perform distal splenorenal shunt due to technical problems, alternative porto-systemic shunt procedure using the adrenal vein as a vascular conduit can be safely employed. © 2007 Aydin et al; licensee BioMed Central Ltd

    Analysing and Recommending Options for Maintaining Universal Coverage with Long-Lasting Insecticidal Nets: The Case of Tanzania in 2011.

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    Tanzania achieved universal coverage with long-lasting insecticidal nets (LLINs) in October 2011, after three years of free mass net distribution campaigns and is now faced with the challenge of maintaining high coverage as nets wear out and the population grows. A process of exploring options for a continuous or "Keep-Up" distribution system was initiated in early 2011. This paper presents for the first time a comprehensive national process to review the major considerations, findings and recommendations for the implementation of a new strategy. Stakeholder meetings and site visits were conducted in five locations in Tanzania to garner stakeholder input on the proposed distribution systems. Coverage levels for LLINs and their decline over time were modelled using NetCALC software, taking realistic net decay rates, current demographic profiles and other relevant parameters into consideration. Costs of the different distribution systems were estimated using local data. LLIN delivery was considered via mass campaigns, Antenatal Care-Expanded Programme on Immunization (ANC/EPI), community-based distribution, schools, the commercial sector and different combinations of the above. Most approaches appeared unlikely to maintain universal coverage when used alone. Mass campaigns, even when combined with a continuation of the Tanzania National Voucher Scheme (TNVS), would produce large temporal fluctuations in coverage levels; over 10 years this strategy would require 63.3 million LLINs and a total cost of 444millionUSD.Communitymechanisms,whileabletodelivertherequirednumbersofLLINs,wouldrequireamassivescaleupinmonitoring,evaluationandsupervisionsystemstoensureaccurateapplicationofidentificationcriteriaatthecommunitylevel.SchoolbasedapproachescombinedwiththeexistingTNVSwouldreachmostTanzanianhouseholdsanddeliver65.4millionLLINsover10yearsatatotalcostof444 million USD. Community mechanisms, while able to deliver the required numbers of LLINs, would require a massive scale-up in monitoring, evaluation and supervision systems to ensure accurate application of identification criteria at the community level. School-based approaches combined with the existing TNVS would reach most Tanzanian households and deliver 65.4 million LLINs over 10 years at a total cost of 449 million USD and ensure continuous coverage. The cost of each strategy was largely driven by the number of LLINs delivered. The most cost-efficient strategy to maintain universal coverage is one that best optimizes the numbers of LLINs needed over time. A school-based approach using vouchers targeting all students in Standards 1, 3, 5, 7 and Forms 1 and 2 in combination with the TNVS appears to meet best the criteria of effectiveness, equity and efficiency

    Measurements in two bases are sufficient for certifying high-dimensional entanglement

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    High-dimensional encoding of quantum information provides a promising method of transcending current limitations in quantum communication. One of the central challenges in the pursuit of such an approach is the certification of high-dimensional entanglement. In particular, it is desirable to do so without resorting to inefficient full state tomography. Here, we show how carefully constructed measurements in two bases (one of which is not orthonormal) can be used to faithfully and efficiently certify bipartite high-dimensional states and their entanglement for any physical platform. To showcase the practicality of this approach under realistic conditions, we put it to the test for photons entangled in their orbital angular momentum. In our experimental setup, we are able to verify 9-dimensional entanglement for a pair of photons on a 11-dimensional subspace each, at present the highest amount certified without any assumptions on the state.Comment: 11+14 pages, 2+7 figure
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