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Search Results: 1 - 10 of 140237 matches for " Ashok K. Alva "
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Growth, Yield and Water Use Effeciency of Forage Sorghum as Affected by Npk Fertilizer and Deficit Irrigation  [PDF]
Mohamed M. Hussein, Ashok K. Alva
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.513225
Abstract:

Drought stress (DS) is an important limiting factor for crop growth and production in some regions of the world. Limitation in water availability precludes optimal irrigation in some production regions. Therefore, investigations on the interaction of other factors to mitigate the DS to varying degree are important. Two field experiments were conducted in the experimental farm of the National Research Centre, Shalakan, Kalubia Governorate, Egypt, during 2004 and 2005 summer seasons to evaluate the interactions between N, P, K rates and optimal vs. deficit irrigation regimes on biomass yield as well as water use efficiency (WUE) of forage sorghum. Omission of the 4th irrigation significantly decreased the biomass of sorghum c.v. Pioneer, as compared to that of the plants receiving optimal irrigation or subject to omission of the 2nd irrigation. The biomass yield increased with an increase in NPK fertilizer rates. Plant height and leaf area also decreased by omitting the 2nd irrigation as compared to that of the plants under optimal irrigation, and further declined with omission of the 4th irrigation. The biomass of the plants (dry weight basis) that received the high N, P, K rates was greater by 26%, 29%, and 35% as compared to that of the plants that received no N, P, K fertilizers, under optimal irrigation, omission of the 2nd, and omission of the 4th irrigation, respectively. The corresponding increases in water use efficiency (based on fresh weight yield) were 37%, 42%, and 55%.

A Rapid Technique for Prediction of Nutrient Release from Polymer Coated Controlled Release Fertilizers  [PDF]
Shengsen Wang, Ashok K. Alva, Yuncong Li, Min Zhang
Open Journal of Soil Science (OJSS) , 2011, DOI: 10.4236/ojss.2011.12005
Abstract: Controlled release fertilizers (CRF) are produced with different rates and durations of nutrient release to cater to different crops with wide ranges of nutrient requirements. A rapid technique is needed to verify the label specifications of nutrient release rate and duration. Polymer-coated urea (PCU) (43% nitrogen [N]) and polymer-coated N, phosphorus (P), potassium (K) (PC_NPK; 14-14-14) fertilizer products were used in this study. Soil incubation of the above CRF products at 25℃ showed that 63.6% to 70.8% of total N was released over 220 days (d). At 100℃ in water 100% of N release occurred in about 168 to 216 hours (h). Regression equations were developed for cumulative nutrient release as a function of release time separately at 25℃ and 100℃. Using the above regressions, the release duration for a given percent nutrient release at each temperature was calculated. These values were then used to establish a relationship between the release duration at 25℃ as a function of that at 100℃. This relationship is useful to predict the release duration at 25℃ of an unknown CRF product by conducting a rapid release test in water at 100℃. This study demonstrated that a rapid nutrient release test at 100℃ successfully predicted nutrient release rate and duration at 25℃, for polymer coated fertilizers. Therefore, this rapid test can be used to verify the label release rate and duration of most CRF products.
Water and Nitrogen Management Effects on Biomass Accumulation and Partitioning in Two Potato Cultivars  [PDF]
Ashok K. Alva, Helena Ren, Amber D. Moore
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.31019
Abstract: Biomass accumulation and partitioning into different plant parts is a dynamic process during the plant growing period, which is influenced by crop management and climate factors. Adequate knowledge of biomass partitioning is important to manage the crops to gain maximum partitioning of assimilates into plant parts of economic significance, i.e. tubers in potato. This study was conducted using two potato cultivars grown in a sandy soil with center pivot irrigation under full irrigation (FI; irrigation to replenish 100% of water loss by evapotranspiration [ET]) and deficit irrigation (DI; replenish only 80% ET) and two nitrogen(N) rates (pre-plant + in-seasonN rates of 56 + 112 or 168 + 336 kg/ha). Plant samples were taken on 22, 44, 66, and 98 days after seedling emergence (DAE). With high N rate, tuber biomass of ‘Umatilla Russet’ cultivar in relation to total plant biomass varied from 23% - 88% and 25% - 86% over 22 to 98 DAE for the FI and DI treatments, respectively. The corresponding partitioning ranges were 30% - 93% and 38% - 93% at the low N rate. With respect to the‘Ranger Russet’ cultivar, biomass partitioning to tubers ranged from 36% - 82% and 23% - 84% for the FI and DI, respectively, at the high N rate, and 29% - 87% and 39% - 95% at the low N rate. Overall, this study demonstrated that within the range of N rate and irrigation treatments the biomass portioning into tubers was largely similar in both cultivars.
Low grade fibromyxoid sarcoma of the falciform ligament: a case report
K Harish, AC Ashok, NK Alva
BMC Surgery , 2003, DOI: 10.1186/1471-2482-3-7
Abstract: We report a 37 year old man who presented with an abdominal mass and dragging pain. Pre-operative imaging suggested the possibility of a subcapsular hemangioma of liver.Laparoscopy was useful to locate the tumor as arising from falciform ligament and made the subsequent surgery simpler. This is one of the large fibromyxoid sarcomas to be reported.Low grade fibromyxoid sarcomas (LGFMS) of the soft tissues are usually situated in the deep soft tissues of the lower extremity, particularly the thigh [1]. It is seen in a young or middle aged adult and is more common in the male. Though they are sporadically seen in other areas like the chest wall or shoulder they are very rarely reported in an intra-abdominal location. We report a 37-year old man with a giant intra-abdominal low grade fibromyxoid sarcoma measuring 21 cm in size; which was mistaken for a possible hemangioma of the liver on CT scan.A 37 year old man noticed a mass in the epigastric region since four months and dull non radiating pain in the epigastrium since a month and a half. A few distended veins were seen over the abdominal wall. Abdominal examination revealed a non tender firm intra-abdominal mass in the epigastrium moving with respiration. A doubtful lateral mobility was present. An ultrasound study of the abdomen showed a large well encapsulated mass in the left lobe of liver with caudal exophytic expansion [Fig 1]. CT scan demonstrated the lesion extrinsically indenting stomach showing initial peripheral enhancement with centripetal filling on time delay [Fig 2]. There was no calcification. The mass was situated between the anterior abdominal wall and liver; but in close relation to the latter. In view of these findings, the possibility of a sub capsular mass, probably a hemangioma on the anterior surface of the left lobe of liver was considered. Biochemical and hematological investigations were within normal limits including liver function tests.A pre-operative fine needle aspiration was not done
Cropping Systems to Improve Carbon Sequestration for Mitigation of Climate Change  [PDF]
Qingren Wang, Yuncong Li, Ashok Alva
Journal of Environmental Protection (JEP) , 2010, DOI: 10.4236/jep.2010.13025
Abstract: The recent trend of an increase in the concentration of greenhouse gases (GHGs) in the atmosphere has led to an ele-vated concern and urgency to adopt measures for carbon (C) sequestration to mitigate the climate change. Among all GHGs, carbon dioxide (CO2) is the most important one which occurs in the greatest concentration and has the strong-est radiative forcing among all. Reducing the release of CO2 to the atmosphere through “green energy” technologies or fossil fuel energy alternatives, such as wind, solar and hydraulic energies, is a major challenge. However, removal of atmospheric CO2 by terrestrial ecosystems via C sequestration and converting the sequestered C into the soil organic C has provided a great opportunity for shifting GHG emission to mitigate the climate change. Soil is an ideal reservoir for storage of organic C since soil organic C has been depleted due to land misuse and inappropriate management through the long history. To optimize the efficiency of C sequestration in agriculture, cropping systems, such as crop rotation, intercropping, cover cropping, etc., play a critical role by influencing optimal yield, total increased C sequestered with biomass, and that remained in the soil. As matter of fact, soil C sequestration is a multiple purpose strategy. It restores degraded soils, enhances the land productivity, improves the diversity, protects the environment and reduces the enrichment of atmospheric CO2, hence shifts emission of GHGs and mitigates climate change.
Growing Cover Crops to Improve Biomass Accumulation and Carbon Sequestration: A Phytotron Study  [PDF]
Qingren Wang, Yuncong Li, Ashok Alva
Journal of Environmental Protection (JEP) , 2010, DOI: 10.4236/jep.2010.12010
Abstract: Cover crop system has shown a potential approach to improving carbon sequestration and environmental quality. Six of each winter and summer cover crops were subsequently grown in two soils, Krome gravelly loam soil (KGL), and Quincy fine sandy soil (QFS), in phytotrons at 3 temperatures (10/20, 15/25, 25/30oC for winter/summer cover crops) to investigate their contributions for carbon (C) sequestration. Among winter cover crops, the highest and the lowest amounts of C accumulated were by bellbean (Vicia faba L.), 597 g/m2 and white clover (Trifolium repens), 149 g/m2, respectively, in the QFS soil. Among summer cover crops, sunn hemp (Crotalaria juncea L.) accumulated the largest quantity of C (481 g/m2), while that by castorbean (Ricinus communis) was 102 g/m2 at 30oC in the KGL soil. The mean net C remained in the residues following the 127 d decomposition were 187 g/m2 of C (73% of the total) and 91 g/m2 (52% of the total) for the winter and summer cover crops, respectively. Following a whole cycle of winter and summer cover crops grown, the mean soil organic C (SOC) increased by 13.8 and 39.1% in the KGL and QFS soil, respectively, compared to the respective soils before. The results suggest that triticale, ryegrass, and bellbean are the promising winter cover crops in the QFS soil, while sunn hemp, velvetbean (Mucuna pruriens), and sorghum sudangrass (Sorghum bicolor × S. bicolor) are recommended summer cover crops for both soils under favorable temperatures.
Effects of Zinc and Ascorbic Acid Application on the Growth and Photosynthetic Pigments of Millet Plants Grown under Different Salinity  [PDF]
M. M. Hussein, A. K. Alva
Agricultural Sciences (AS) , 2014, DOI: 10.4236/as.2014.513133
Abstract:

Salinity stress impacts crop growth as well as production. The need for increased food production to feed the increasing population and the limited resources, i.e. optimal quality land and water, require developing strategies to mitigate marginal stresses, including salinity stress, for reasonable expectation of crop production. A pot experiment was conducted in a greenhouse at the National Research Centre, Dokki, Cairo, Egypt in the summer season of 2005 to evaluate the effects of foliar application of ascorbic acid alone or in combination with zinc sulfate on the growth and photosynthetic pigments of millet plants irrigated by tap water (250 ppm, 0.39 dS·m-1) or moderate to high salinity irrigation water [2500 ppm (3.9 dS·m-1) and 5000 ppm (7.8 dS·m-1)]. Increased salinity in the irrigation water decreased the plant growth, biomass, and carotenoid content. Foliar application of ascorbic acid alone increased number of leaves and leaf area, while in combination with zinc sulfate increased the plant height and total plant biomass. However, these treatments had no significant effects on the photosynthetic pigments. This study demonstrates that exogenous application of ascorbic acid can enhance foliar growth which may contribute to increased plant biomass and yield.

Do wiadczenie i eksperyment w sztuce
Alva No?
Avant : Journal of Philosophical-Interdisciplinary Vanguard , 2011,
Abstract: A significant impediment to the study of perceptual consciousness is our dependence on simplistic ideas about what experience is like. This is a point that has been made by Wittgenstein, and by philosophers working in the Phenomenological Tradition, such as Husserl and Merleau-Ponty. Importantly, it is an observation that has been brought to the fore in recent discussions of consciousness among philosophers and cognitive scientists who have come to feel the need for a more rigorous phenomenology of experience. The central thought of this paper is that art can make a needed contribution to the study of perceptual consciousness. The work of some artists can teach us about perceptual consciousness by furnishing us with the opportunity to have a special kind of reflective experience. In this way, art can be a tool for phenomenological investigation. The paper has three parts. First, I present what I call the problem of the transparency of experience. This is a problem for philosophy, for art, and for cognitive science. Second, I present an alternative conception of experience as a mode of interactive engagement with the environment. Finally, against the background of this conception, I discuss, briefly, the work of the sculptors Richard Serra and Tony Smith.
Do wiadczanie wiata w czasie
Alva No?
Avant : Journal of Philosophical-Interdisciplinary Vanguard , 2011,
Abstract: Objects – even tomatoes – are, in a sense, timeless – they exist, all at once, whole and integrated. Indeed, it is just this fact about objects – their timelessness – that makes it puzzling how we can experience them as we do. In the language of traditional philosophy, objects are transcendent; they outstrip our experience; they have hidden parts, always. When you perceive an object, you never take it in from all sides at once. And yet you have a sense of the presence of the object as a whole at a moment in time.
Microwave Synthesis, Characterization and Photocatalytic Properties of SnO2 Nanoparticles  [PDF]
Ashok K. Singh, Umesh T. Nakate
Advances in Nanoparticles (ANP) , 2013, DOI: 10.4236/anp.2013.21012
Abstract:

In the present endeavour, SnO2 nanoparticles (NPs) were synthesized using microwave method. Synthesized SnO2 NPs were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrscopy (EDS) to find their structure, morphology and elemental composition. SnO2 NPs were of spherical morphology having crystallite size of 35.42 nm as obtained from Scherrer’s formula using most intense peak of XRD. Synthesized NPs were used for photodegradation of melthylene blue (MB) dye under UV light. The SnO2 NPs ware found to have photodegradation efficiency and apparent rate constant of 55.97% and 2.149 × 10_2 respectively.


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