1,271 research outputs found
Egranary as a Digital Resource in Uganda: Preliminary Findings
In this paper, we address preliminary findings from a digital literacy study on the use the portable digital library, eGranary, currently being conducted in a rural Ugandan school. The eGranary system is an intranet that comprises a 750Gb harddrive with specialized browsing software, which can be attached to a PC or a local area network. It contains approximately 10 million educational documents, including Wikipedia, which can be searched like the internet (see www.egranary.org). Drawing on theories of new literacies and identities, the two research questions we are addressing in our current project are as follows: (i) how does eGranary function as a placed resource in Ugandan society? (ii) to what extent do identities shift as teachers learn from and contribute to global knowledge production? These research questions are centrally concerned with the innovative use of educational resources to promote social inclusion in poorly resourced regions of the world.\u
Screen house and field resistance of taro cultivars to taro leaf blight disease (Phytophtora colocasiae)
Article PurchasedIntroduction: Taro leaf blight disease cause by Phytophtora colocasiae has become an economic disease in Cocoyam growing regions of Cameroon.
Aims: To screen for resistance 10 improved and 4 local cultivars of taro against taro leaf blight disease.
Study Design: A randomized complete block design study.
Place of Study: Studies were conducted at the International Institute of Tropical Agriculture (IITA) Yaounde Nkolbisson from July 2013 to January 2014.
Methodology: Taro cultivars from tissue culture were planted in the screen house conditions and tested for virulence and pathogenicity with 4 isolates of Phythophthora colocasiae at spore density of 3×104 spores /ml of distilled water. Plants were planted in the field to assess disease incidence and severity.
Results: The results obtained on the different taro cultivars, revealed that all the 4 isolates showed variable pathogenicity. They caused lesions on inoculated leaves. There was variability in pathogenicity based on the small lesion lengths produced on cultivars, these included BL/SM132 and Red petiole. Isolate 3 showed a stronger sensitivity to leaf collapse and defoliation irrespective of the cultivar tested. There was a significant difference (p = 0.05) in tissue collapse and leaf defoliation on exposure to the different fungal isolates. The result of field infection rates of P. colocasiae at 126 DAP-154 DAP on 10 improved and 4 local cultivars indicated that there was significant variability (p = 0.05) in incidence and disease severity, with high incidence and severity occurring at 154 DAP in all cultivars. Improved cultivar BL/SM132 showed no classic symptoms of
P. colocasiae and therefore it was resistant to Phytophthora colocasiae.
Conclusion: The results obtained on virulence and pathogenicity of Phythophthora colocasiae on the different taro cultivars revealed that all the 4 isolates showed variable pathogenicity. They caused lesions, on inoculated leaves. Isolate 3 showed a stronger sensitivity to leaf collapse and defoliation irrespective of the cultivar tested. The result of field infection rates of P. colocasiae at 126 DAP-154 DAP on 10 improved and 4 local cultivars indicated that there was a significant variability (p = 0.05) in disease incidence and severity, with high incidence and severity occurring at 154 DAP in all cultivars. Improved cultivar BL/SM132 showed no classic symptoms of P. colocasiae and therefore it was resistant to Phytophthora colocasiae as compared to all the other cultivars which showed high severity rates of infection of the disease and thus were susceptible to the
disease
Application of in-vitro micropropagation technique for sustainable production of four local taro cultivars [Colocasia esculenta (L.) Schott] in Cameroon
Open Access JournalTaro leaf blight disease has recently been reported in Cameroon to cause between 50 and 100% yields loss of taro in most of the agro-ecological crop growing regions. This has led to a significant reduction in disease-free planting materials, edible crop and increased. The Meristem culture technique has been used to produce crop plants free of viruses and fungi especially in vegetative propagated colocassia plants. This aimed at applying in-vitro micro-propagation technique for sustainable production of four local taro cultivars in Cameroon. This study was conducted at the Root and Tuber Tissue Culture Laboratory, of the Institute of Agricultural Research for Development (IRAD), Bambui from April 2015 to November 2016. Micro-plants from four local taro cultivars were produced in vitro from apical meristem tips. The tip meristems were excised from corms of the four local taro cultivars. The excised explants were surface sterilized with alcohol and sodium hypochlorite in sequence steps at different concentrations. Meristems were cultured at establishment stage on Murashige and Skoog (MS) medium with 30 g of sugar, 1.1 ml of 6-benzylaminopurine and 7 g of agar. Shoots proliferation was induced in MS with 2.2 ml of 6-benzylaminopurine (BAP). Result shows a significant difference at p≤0.5 in number of shoots, petiole length, open leaf and corm diameter among the cultivars and no significant variation in mean number of senescence leaf with respect to all the cultivars, at 60 days of shoot tip culture. At rooting stage, taro shoots were cultured on MS media supplemented with 10 ml of 0.1 mg/ml naphthalene acetic-acid (NAA). Roots were produced on all the cultivars with excellent mean growth rate of 14.7 ± 0.69 recorded in cultivar with dark green petiole and small leaves
A review of social issues for biofuels investment in Mozambique
This study discusses the potential for expanding cultivation of biofuel feedstock in Mozambique from several angles. Taking the case of sugarcane, it explores the potential to expand production, through exploring both biophysical factors and patterns of existing investment. We review recent literature on trends in land allocation and practices of resettlement in Mozambique to highlight opportunities and constraints that current plans for biofuel production should consider. While resource availability suggest opportunities exist to expand cultivation, minimizing social risks when doing so depends on the processes followed to transfer land from existing users, and compensation in the short and long term
Impact of fungicide application on taro leaf blight disease in three regions of Cameroon
Open Access JournalThe study was conducted in the research field sites of the Institute of Agricultural Research (IRAD), Bambui, North West Region, (IRAD), Ekona South West Region and the International Institute of Tropical Agriculture (IITA) Nkolbisson, Yaoundé, Center Region of Cameroon. Four cultivars of taro (Dark green petiole with small leaves (L1), Red petiole with small leaves (L2), Light green petiole with large leaves (L3) and Light green petiole with small leaves(L4)) were planted in four seasons, for two years, in the months of March and July 2015, March and July 2016 in all the research farms. Ninety corms of the each cultivar were treated before planting with fungiforce at 0.33% concentration while others were not treated. Fungiforce is a contact and systemic fungicide containing high levels of copper oxide (600 grams) and mild levels of metalaxyl (120 grams), various concentrations of 0.4%, 0.33%, 0.27%, at the onset of the first symptom of leaf blight on the leaves using knapsack sprayer of 15 litres at two weeks interval, while the control experiment consisted of unsprayed taro leaves. Data for the disease incidence of taro leaf blight was recorded from the onset of disease in fields and continued at two weeks interval for 6 weeks. The results of planting taro in four seasons in three experimental field sites revealed that there was a decrease in disease incidence in fields sprayed with fungiforce than in the control field. Plots sprayed with fungicide at different concentrations showed no variation on the 4 cultivars in the different field sites. The disease incidence ranged from 10% to 100% in the 4 seasons, at the three experimental field sites. The variation in disease incidence in the three planting sites is an indication of possible genotypes by environment (GXE) interaction that may have significant influence on the taro leaf blight resistance potential
Calculation of absolute free energy of binding for theophylline and its analogs to RNA aptamer using nonequilibrium work values
The massively parallel computation of absolute binding free energy with a
well-equilibrated system (MP-CAFEE) has been developed [H. Fujitani, Y. Tanida,
M. Ito, G. Jayachandran, C. D. Snow, M. R. Shirts, E. J. Sorin, and V. S.
Pande, J. Chem. Phys. , 084108 (2005)]. As an application, we
perform the binding affinity calculations of six theophylline-related ligands
with RNA aptamer. Basically, our method is applicable when using many compute
nodes to accelerate simulations, thus a parallel computing system is also
developed. To further reduce the computational cost, the adequate non-uniform
intervals of coupling constant , connecting two equilibrium states,
namely bound and unbound, are determined. The absolute binding energies thus obtained have effective linear relation between the computed and
experimental values. If the results of two other different methods are
compared, thermodynamic integration (TI) and molecular mechanics
Poisson-Boltzmann surface area (MM-PBSA) by the paper of Gouda [H.
Gouda, I. D. Kuntz, D. A. Case, and P. A. Kollman, Biopolymers , 16
(2003)], the predictive accuracy of the relative values is
almost comparable to that of TI: the correlation coefficients (R) obtained are
0.99 (this work), 0.97 (TI), and 0.78 (MM-PBSA). On absolute binding energies
meanwhile, a constant energy shift of -7 kcal/mol against the
experimental values is evident. To solve this problem, several presumable
reasons are investigated.Comment: 23 pages including 6 figure
The Role of Ground-Source Heat Pumps in Achieving New Jersey’s 80% by 2050 Goal: Addressing Emissions from the Buildings Sector
Emissions reduction and renewable energy sources are vital to health of New Jersey. Governor Murphy’s executive orders and recent legislation target actions to improve our environment and create a sustainable future. The buildings sector is recognized as the second largest source of greenhouse gas emissions in New Jersey behind transportation, with the majority of emissions due to fossil fuel-based heating and cooling. To reach state’s goal of 80% emissions reduction by 2050, reduction strategies for the built environment must implement technologies that displace fossil fuels and maximize clean and low-carbon electricity. Heat pumps are a key technology because of their high efficiency and capability to integrate with the increasing electrification of systems and end uses. Ground-source heat pumps notably deliver the highest efficiencies and therefore the deepest emissions reductions, even in extreme weather conditions. This presentation will discuss the current market conditions, challenges to adoption, and the NJDEP efforts to support the deployment of ground-source heat pumps
Modeling the growth of stylolites in sedimentary rocks
[1] Stylolites are ubiquitous pressure solution seams found in sedimentary rocks. Their morphology is shown to follow two self-affine regimes. Analyzing the scaling properties of their height over their average direction shows that (1) at small scale, they are self-affine surfaces with a Hurst exponent around 1, and (2) at large scale, they follow another self-affine scaling with Hurst exponent around 0.5. In the present paper, we show theoretically the influence of the main principal stress and the local geometry of the stylolitic interface on the dissolution reaction rate. We compute how it is affected by the deviation between the principal stress axis and the local interface between the rock and the soft material in the stylolite. The free energy entering in the dissolution reaction kinetics is expressed from the surface energy term and via integration from the stress perturbations due to these local misalignments. The resulting model shows the interface evolution at different stress conditions. In the stylolitic case, i.e., when the main principal stress is normal to the interface, two different stabilizing terms dominate at small and large scales which are linked respectively to the surface energy and to the elastic interactions. Integrating the presence of small-scale heterogeneities related to the rock properties of the grains in the model leads to the formulation of a Langevin equation predicting the dynamic evolution of the surface. This equation leads to saturated surfaces obeying the two observed scaling laws. Analytical and numerical analysis of this surface evolution model shows that the crossover length separating both scaling regimes depends directly on the applied far-field stress magnitude. This method gives the basis for the development of a paleostress magnitude marker. We apply the computation of this marker, i.e., the morphological analysis, on a stylolite found in the Dogger limestone layer located in the neighborhood of the ANDRA Underground Research Laboratory at Bure (eastern France). The results are consistent with the two scaling regimes expected, and the practical determination of the major principal paleostress, from the estimation of a crossover length, is illustrated on this example
Preservation of, and access to oral history records at Pietermaritzburg Archives Repository.
Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.The study investigated the importance of oral history and how oral history is preserved and
accessed at the Pietermaritzburg Archives Repository (PAR), specifically at its Oral History
Unit (OHU). Oral history confirms information about historical events by enhancing and verifying the event. It also recovers certain aspects of the past event that may not have been captured. Data were collected through three different semi-structured interviews, observation and graphic data in the form of photographs. Qualitative analysis of the data was done via content, conceptual and thematic analysis.
The study found that the preservation and access to oral history records have been ineffective
since the OHU was established in 2013. Issues identified included legislation which does not
provide for oral history records in the contemporary digital era, the lack of policy, deficient
strategies for preservation and access, the inadequacy of the adapted building and a shortage
of resources, funding and qualified staff. The overall recommendation arising from the findings was a need to improve the preservation and access of oral history records in the PAR. More specifically, the study recommends the modification of the KwaZulu-Natal Archives and Records Services Act (No. 8 of 2011 as
amended) to fully accommodate the oral history records and the preservation and access of audio-visual material, the formulation of policy, the establishment of a new archival building, the recruitment of information professionals who understand the pros and cons of archival science, further training of existing staff members with regard to preservation and access of oral history records, and finally, the need for the KwaZulu-Natal Department of Arts and Culture to increase the budget allocation for the Provincial Archives. A suggestion for further research ended the study
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