932 research outputs found

    Food Insecurity and Conflict Events in Africa

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    Control of Phomopsis Blight of Egg Plant through Fertilizer and Fungicide Management

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    The experiments were conducted at Laboratory of the Department of Plant Pathology and in the farm of Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh during Rabi season of the year 2007-2008. Four fungicides viz. Bavistin 50 WP (Carbendazim), Tilt 250 EC (Propiconazole), Cupravit 50 WP (Copperoxychloride) and Dithane M-45 (Mancozeb) and micronutrients (Gypsum, ZnO and Boric acid) were evaluated against Phomopsis vexans causing Phomopsis blight and fruit rot of eggplant. The fungicides and micronutrients either applied individually or in combination showed significant effect in terms of per cent leaf infection, fruit infection, leaf area diseased and fruit area diseased in comparison to control. Effect of each fungicide applied in combination with micronutrients always showed better performance in reducing disease incidence and disease severity than the fungicides applied alone. Among the fungicides, Bavistin 50 WP (0.1%) proved to be effective arresting the spore germination and mycelia growth of Phomopsis vexans assayed in in vitro test. Reduction of leaf area diseased caused by Bavistin 50 WP (0.1%) in combination with micronutrients were 58.17, 67.37, 78.41 and 85.25%, respectively at preflowering, post-flowering, fruiting and fruit ripening stages while Bavistin 50 WP (0.1%) alone reduced by 52.22, 58.67, 74.19 and 83.09%, respectively at those stages. Similarly reduction of fruit area diseased caused by Bavistin 50 WP (0.1%) in combination with micronutrients were 57.93 and 79.79%, respectively at fruiting and fruit ripening stages while Bavistin 50WP (0.1%) alone reduced by 56.93 and 76.14%, respectively at those stages. Micronutrients had little effect against the disease but significantly better than control.Int. J. Agril. Res. Innov. & Tech. 3 (1): 66-72, June, 2013 DOI: http://dx.doi.org/10.3329/ijarit.v3i1.1609

    Targeted photodestruction of human colon cancer cells using charged Dougherty chlorine6immunoconjugates

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    The goal of this study was to develop a strategy for the selective destruction of colorectal cancer cells. Towards this end, photoimmunoconjugates were prepared between the anti-colon cancer monoclonal antibody 17.1A and the photosensitizer (PS) chlorine6(ce6). Polylysine linkers bearing several ce6molecules were covalently attached in a site-specific manner to partially reduced IgG molecules, which allowed photoimmunoconjugates to bear either cationic or anionic charges. The conjugates retained immunoreactivity as shown by enzyme-linked immunosorbent assays and by competition studies with native antibody. The overall charge on the photoimmunoconjugate was an important determinant of PS delivery. The cationic photoimmunoconjugate delivered 4 times more ce6to the cells than the anionic photoimmunoconjugate, and both 17.1A conjugates showed, in comparison to non-specific rabbit IgG conjugates, selectivity for antigen-positive target cells. Illumination with only 3 J cm−2of 666 nm light reduced the number of colony forming cells by more than 90% for the cationic 17.1A conjugate and by 73% for the anionic 17.1A conjugate after incubation with 1 μM ce6equivalent of the respective conjugates. By contrast, 1 μM free ce6gave only a 35% reduction in colonies. These data suggest photoimmunoconjugates may have applications in photoimmunotherapy where destruction of colorectal cancer cells is required. © 2000 Cancer Research Campaig

    Human-like Planning for Reaching in Cluttered Environments

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    Humans, in comparison to robots, are remarkably adept at reaching for objects in cluttered environments. The best existing robot planners are based on random sampling of configuration space- which becomes excessively high-dimensional with large number of objects. Consequently, most planners often fail to efficiently find object manipulation plans in such environments. We addressed this problem by identifying high-level manipulation plans in humans, and transferring these skills to robot planners. We used virtual reality to capture human participants reaching for a target object on a tabletop cluttered with obstacles. From this, we devised a qualitative representation of the task space to abstract the decision making, irrespective of the number of obstacles. Based on this representation, human demonstrations were segmented and used to train decision classifiers. Using these classifiers, our planner produced a list of waypoints in task space. These waypoints provided a high-level plan, which could be transferred to an arbitrary robot model and used to initialise a local trajectory optimiser. We evaluated this approach through testing on unseen human VR data, a physics-based robot simulation, and a real robot (dataset and code are publicly available 1 ). We found that the human-like planner outperformed a state-of-the-art standard trajectory optimisation algorithm, and was able to generate effective strategies for rapid planning- irrespective of the number of obstacles in the environment

    Ripple modulated electronic structure of a 3D topological insulator

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    3D topological insulators, similar to the Dirac material graphene, host linearly dispersing states with unique properties and a strong potential for applications. A key, missing element in realizing some of the more exotic states in topological insulators is the ability to manipulate local electronic properties. Analogy with graphene suggests a possible avenue via a topographic route by the formation of superlattice structures such as a moir\'e patterns or ripples, which can induce controlled potential variations. However, while the charge and lattice degrees of freedom are intimately coupled in graphene, it is not clear a priori how a physical buckling or ripples might influence the electronic structure of topological insulators. Here we use Fourier transform scanning tunneling spectroscopy to determine the effects of a one-dimensional periodic buckling on the electronic properties of Bi2Te3. By tracking the spatial variations of the scattering vector of the interference patterns as well as features associated with bulk density of states, we show that the buckling creates a periodic potential modulation, which in turn modulates the surface and the bulk states. The strong correlation between the topographic ripples and electronic structure indicates that while doping alone is insufficient to create predetermined potential landscapes, creating ripples provides a path to controlling the potential seen by the Dirac electrons on a local scale. Such rippled features may be engineered by strain in thin films and may find use in future applications of topological insulators.Comment: Nature Communications (accepted

    Fractional quantum Hall effect in the absence of Landau levels

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    It has been well-known that topological phenomena with fractional excitations, i.e., the fractional quantum Hall effect (FQHE) \cite{Tsui1982} will emerge when electrons move in Landau levels. In this letter, we report the discovery of the FQHE in the absence of Landau levels in an interacting fermion model. The non-interacting part of our Hamiltonian is the recently proposed topologically nontrivial flat band model on the checkerboard lattice \cite{sun}. In the presence of nearest-neighboring repulsion (UU), we find that at 1/3 filling, the Fermi-liquid state is unstable towards FQHE. At 1/5 filling, however, a next-nearest-neighboring repulsion is needed for the occurrence of the 1/5 FQHE when UU is not too strong. We demonstrate the characteristic features of these novel states and determine the phase diagram correspondingly.Comment: 6 pages and 4 figure

    Non-destructive maturity index of “Amritsagor” banana using RGB and HSV values

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    Massive changes in physicochemical composition and color variation usually occur in fruits during maturation and ripening. This study is conducted to implement an image processing system and develop a maturity color chart of banana. Actually, natural ripening color is different than impose ripening. Maturity color chart will help the consumer when it will be in the packet of banana. The earliest physiological maturity (stage-1) was marked as the stage when the flesh color was olive green and the pulp turning yellow and the subsequent maturity stages determined whenever changes the color as stage-2 (green smoke), stage-3 (apple green), stage-4 (olive drab), stage-5 (yellow) and stage-6 (golden rod) color. For each of the maturity stages, physical (peel color, firmness, and weight loss) and biochemical (anthocyanin content, carotenoids content, titrable acidity, pH, total soluble solids, ascorbic acid, reducing sugar, non-reducing sugar, and total sugar) maturity indices were determined. We had classified the maturity stages of banana based on the RGB (Red, Green, and Blue) and HSV (Hue, Saturation and Value) values. Average, median, minimum and maximum values were used in this study. After completing the qualitative analysis of RGB and HSV values we found the correlation coefficient of RGB and HSV values. The red color (R) values of bananas would increase when stages increase and the hue (H) means the pure color of bananas decreases when stages increase. Therefore, we can say that maturity stages of bananas mainly depend on R and H values. In case of Amritsagor banana at stage-6 (golden rod) color, TSS (Total Soluble Solid) (2.1%), TA (Titrable Acidity) (0.96%), pH (5.2), sugar (1.25%), vitamin C (2.5 mg/100g), reducing sugar (1.04%), non-reducing sugar (0.2%), anthocyanin (0.55 mg/100g) carotenoids (0.38 mg/100g) and at stage-1 (olive green) color, pH (6.8), vitamin C (8.75 mg/100g) are significantly highest. The results show that as maturation progressed, firmness decreased gradually and flesh color turned olive green to golden rod with ripening. Total soluble solids increased while TA (Titrable acidity) gradually increased with maturity. The results revealed that, there is a significant relationship between nutritional value, firmness and fruit skin color. So, the fruit of stage-1 (olive green) is suitable for harvesting and stages-6 (golden rod) color is suitable for consumption. Actually this message for grower/ owner or who would like to harvest and consumer. Fruit is banana, to observe the change of color keep it at room temperature. Neither artificial nor chemical system used here. Each and every box will carry the real maturity color chart

    Consecutive bites on two persons by the same cobra: a case report

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    In tropical countries like Bangladesh, persons are bitten by snakes every day and a considerable number of patients die en route to the hospital. An event of consecutive neurotoxic bites on two men by a single snake was observed in the Snake Bite Study Clinic (SBSC) of the Chittagong Medical College Hospital (CMCH). Two brothers, working in their semi-pucca restaurant, were successively bitten by the same cobra on their lower limbs. Within an hour, they were taken to the CMCH. Few minutes after admission, both developed symptoms of neurotoxicity: ptosis, nasal voice, dysphagia, broken neck sign, etc. They received polyvalent antivenom (Haffkine Bio-Pharmaceuticals Company, India) and other auxiliary treatment immediately. Within few hours, neurotoxic features were completely absent. Later, the snake was captured in the restaurant kitchen and identified as monocellate cobra (Naja kauthia) by the SBSC. The elder brother developed significant antivenom reactions and both presented necrosis and ulceration at the bite sites. In these cases, immediate arrival to the hospital and early administration of antivenom resulted in successful recoveries

    Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors

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    The development of highly-sensitive and miniaturized sensors that capable of real-time analytes detection is highly desirable. Nowadays, toxic or colorless gas detection, air pollution monitoring, harmful chemical, pressure, strain, humidity, and temperature sensors based on photonic crystal fiber (PCF) are increasing rapidly due to its compact structure, fast response and efficient light controlling capabilities. The propagating light through the PCF can be controlled by varying the structural parameters and core-cladding materials, as a result, evanescent field can be enhanced significantly which is the main component of the PCF based gas/chemical sensors. The aim of this chapter is to (1) describe the principle operation of PCF based gas/ chemical sensors, (2) discuss the important PCF properties for optical sensors, (3) extensively discuss the different types of microstructured optical fiber based gas/ chemical sensors, (4) study the effects of different core-cladding shapes, and fiber background materials on sensing performance, and (5) highlight the main challenges of PCF based gas/ chemical sensors and possible solutions

    Residual Effects of Organic Manures with Different Levels of Chemical Fertilizers on Rice

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    A field experiment was conducted to evaluate the residual effects of organic manures and different level of recommended fertilizer dose (RFD) on the yield and nutrient uptake of BBRI dhan29 at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh, Bangladesh. The experiment containing seven treatments were laid out in a randomized complete block design with three replications. The treatments were T0 (Control), T1 (100% RFD), T2 (75% RFD + residual effect of CD 5 t ha⁻¹), T3 (75% RFD + residual effect of PM 3 t ha⁻¹), T4 (75% RFD + residual effect of residual effect of Com. 5 t ha⁻¹), T5 (75% RFD + residual effect of CD 2.5 t ha⁻¹, PM 1.5 t ha⁻¹, and Com 2.5 t ha⁻¹) and T6 (50% RFD + residual effect of CD 2.5 t ha⁻¹, PM 1.5 t ha⁻¹, and Com. 2.5 t ha⁻¹). The manures viz. cowdung (CD), poultry manure (PD) and compost (Com.) was applied to the previous crop (T. Aman rice). The recommended doses of fertilizers were used to supply N, P, K and S @ 140, 15, 60 and 15 kg ha⁻¹, respectively to the present crop. Residual effects of organic manure with inorganic fertilizers significantly increased the yield attributes as well as grain and straw yields of rice. Treatment T6 (50% RFD + residual effect of CD 2.5 t ha-1, PM 1.5 t ha⁻¹, and Com. 2.5 t ha⁻¹) produced the highest grain yield (6.87 t ha⁻¹) and straw yield (7.24 t ha⁻¹). The lowest grain yield (3.22 t ha⁻¹) and straw yield (4.55 t ha⁻¹) were found in T0 (Control) treatment. Further, it was observed that T2 (75% RFD + CD 5 t ha⁻¹) performed better compared to T3 (75% RFD + PM 3 t ha⁻¹) and T4 (75% RFD + Com 5 t ha⁻¹) in exerting residual effects. The NPKS contents and uptake were markedly influenced by residual effects of manures and fertilizers. Therefore, treatment T6 receiving 50% RFD along with the residual effect of 2.5 t ha⁻¹cowdung, 1.5 t ha⁻¹ poultry manure and 2.5 t ha⁻¹ 1 compost was found to be the best combination of organic and inorganic fertilizers for obtaining the maximum yield of BRRI dhan2
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