Mobile Cloud Computing Based Technologies for Enhancing E-learning Content Delivery and Sharing in Higher Learning Institutions in Tanzania using Learner-Centered Approach

Electronic learning (E-learning) in Higher Learning Institutions (HLIs) offers a cost-effective teaching and learning that support social interactivity, flexibility, context sensitivity, and active participation of learners in learning activities. The objective of this study was to investigate the challenges facing the traditional E-learning tools and leverage the advanced capacity of Mobile Cloud Computing (MCC) to enhance E-learning service delivery and sharing of learning resources focusing in learner-centered approach. Also, the evolvement of mobile computing devices such as smartphones, Personal Digital Assistance (PDA), and laptops owned by learners bring prospects in overcoming the inherent challenges facing HLIs in developing countries such as shortage of computer laboratories and network resources.Consequently, this study proposes MCC-based E-learning content delivery and sharing to augment higher learning institutions with limited resource setting in developing countries. The main benefits of MCC-based E-learning include, first, augment traditional LMS by provisioning abundant processing capacity and storage in the cloud that guarantee unlimited learning materials available for learners and instructors; Second, improves performance in local Learning Management System (LMS) servers by outsourcing execution and storage into the cloud especially when resource-intensive E-learning contents such as games, Virtual Reality (VR), and video streaming are used for learning; third, supports multi-platforms to execute the workload of various E-learning applications in the cloud which is potential for E-learning resource sharing; and fourth, guarantee cost-effective E-learning content delivery and sharing. Keywords: Mobile cloud computing, E-learning, content delivery, Learner-centered learning DOI: 10.7176/JIEA/13-2-03 Publication date:March 31st 202

Synchronization and Caching Solution for Cost-Effective E-Learning in Resource and Bandwidth Constrained Environments

Electronic learning (e-learning) content delivery and accessibility have received significant research attention over years in order to ensure reliability, availability and cost-effectiveness through Information and Communication Technologies (ICTs).The evolvement of mobile computing devices especially smartphones bring prospects in overcoming the inherent limitations of the Internet when accessing web contents.  Among the potential opportunity revealed includes the ability to work offline. Therefore, this study aims to analyze the existing online and offline e-learning systems in order to explore the uniqueness, technical problems and opportunities in this field. In the same vein, this study proposed synchronization and caching approach for cost-effective e-learning content delivery. The proposed approach synchronizes contents from the original server to local database in mobile computing devices in order to deliver contents to learners in a reliable, cost-effective and timely manner. Finally, comparing existing web-based learning system and the proposed approach, the analyzed results provide empirical evidence that, the proposed approach is significant for bandwidth usage cost saving and hence cost-effectiveness due to ability of working offline. Therefore, synchronization and caching approach cut down several limitations in existing e-learning systems including:  reduction of cost of bandwidth usage; improving system performance by cutting down the servers’ workload and internet usage overheads; cutting down costs of purchasing hardware and increasing motivation in learning activities by allowing learners to access learning contents anywhere and anytime. Keywords: synchronization and caching, e-learning, cost-effectiveness, content delivery, offline

The proficiency of the original host species determines community-level plasmid dynamics

Plasmids are common in natural bacterial communities, facilitating bacterial evolution via horizontal gene transfer. Bacterial species vary in their proficiency to host plasmids: Whereas plasmids are stably maintained in some species regardless of selection for plasmid-encoded genes, in other species, even beneficial plasmids are rapidly lost. It is, however, unclear how this variation in host proficiency affects plasmid persistence in communities. Here, we test this using multispecies bacterial soil communities comprising species varying in their proficiency to host a large conjugative mercury resistance plasmid, pQBR103. The plasmid reached higher community-level abundance where beneficial and when introduced to the community in a more proficient host species. Proficient plasmid host species were also better able to disseminate the plasmid to a wider diversity of host species. These findings suggest that the dynamics of plasmids in natural bacterial communities depend not only upon the plasmid's attributes and the selective environment, but also upon the proficiency of their host species

Algorithms for Highly Symmetric Linear and Integer Programs

This paper deals with exploiting symmetry for solving linear and integer programming problems. Basic properties of linear representations of finite groups can be used to reduce symmetric linear programming to solving linear programs of lower dimension. Combining this approach with knowledge of the geometry of feasible integer solutions yields an algorithm for solving highly symmetric integer linear programs which only takes time which is linear in the number of constraints and quadratic in the dimension.Comment: 21 pages, 1 figure; some references and further comments added, title slightly change

The Wide Field Spectrograph (WiFeS)

This paper describes the Wide Field Spectrograph (WiFeS) under construction at the Research School of Astronomy and Astrophysics (RSAA) of the Australian National University (ANU) for the ANU 2.3m telescope at the Siding Spring Observatory. WiFeS is a powerful integral field, double-beam, concentric, image-slicing spectrograph designed to deliver excellent thoughput, wavelength stability, spectrophotometric performance and superb image quality along with wide spectral coverage throughout the 320-950 nm wavelength region. It provides a 25x38 arcsec. field with 0.5 arcsec. sampling along each of twenty five 38X1 arcsec slitlets. The output format is optimized to match the 4096x4096 pixel CCD detectors in each of two cameras individually optimized for the blue and the red ends of the spectrum, respectively. A process of "interleaved nod-and-shuffle" will be applied to permit quantum noise-limited sky subtraction. Using VPH gratings, spectral resolutions of 3000 and 7000 are provided. The full spectral range is covered in a single exposure at R=3000, and in two exposures in the R=7000 mode. The use of transmissive coated optics, VPH gratings and optimized mirror coatings ensures a throughput (including telescope atmosphere and detector) > 30% over a wide spectral range. The concentric image-slicer design ensures an excellent and uniform image quality across the full field. To maximize scientific return, the whole instrument is configured for remote observing, pipeline data reduction, and the accumulation of calibration image libraries.Comment: Accepted for publication in Astrophysics & Space Science, 16 pages, 14 figure

Sex-Biased Gene Flow Among Elk in the Greater Yellowstone Ecosystem

We quantified patterns of population genetic structure to help understand gene flow among elk populations across the Greater Yellowstone Ecosystem. We sequenced 596 base pairs of the mitochondrial control region of 380 elk from eight populations. Analysis revealed high mitochondrial DNA variation within populations, averaging 13.0 haplotypes with high mean gene diversity (0.85). The genetic differentiation among populations for mitochondrial DNA was relatively high (FST = 0.161; P = 0.001) compared to genetic differentiation for nuclear microsatellite data (FST = 0.002; P = 0.332), which suggested relatively low female gene flow among populations. The estimated ratio of male to female gene flow (mm/mf = 46) was among the highest we have seen reported for large mammals. Genetic distance (for mitochondrial DNA pairwise FST) was not significantly correlated with geographic (Euclidean) distance between populations (Mantel’s r = 0.274, P = 0.168). Large mitochondrial DNA genetic distances (e.g., FST . 0.2) between some of the geographically closest populations (,65 km) suggested behavioral factors and/or landscape features might shape female gene flow patterns. Given the strong sex-biased gene flow, future research and conservation efforts should consider the sexes separately when modeling corridors of gene flow or predicting spread of maternally transmitted diseases. The growing availability of genetic data to compare male vs. female gene flow provides many exciting opportunities to explore the magnitude, causes, and implications of sex-biased gene flow likely to occur in many species