Enjoyed or bored?:A study into achievement emotions and the association with barriers to learning in MOOCs

MOOCs are accessible online personal development opportunities in which learners can expand their knowledge on many topics. Yet, the experience of barriers to learning often hinders learners from achieving their personal learning goals. Therefore, it is important to have insight into determinants that may influence the experience of (certain) barriers. This study investigated whether the emotional determinants enjoyment and boredom, which are known to impact learner achievement and motivation, affect the experience of (specific) barriers while learning in MOOCs. The results show that boredom did affect the experience of barriers related to technical and online related skills, social context and time, support and motivation, yet it did not affect the experience of barriers related to the design of the MOOC. Enjoyment was not correlated to any of the barriers. Furthermore, the same analysis comparing men to women again revealed that boredom did not significantly affect the experience of barriers related to the design of the MOOC, yet did significantly affect the experience of the other barriers. No, significant differences were found between males and females. These findings may serve as input for supporting learners in achieving their individual learning goals

Enzymatic Analysis of Recombinant Japanese Encephalitis Virus NS2B(H)-NS3pro Protease with Fluorogenic Model Peptide Substrates

Background Japanese encephalitis virus (JEV), a member of the Flaviviridae family, causes around 68,000 encephalitis cases annually, of which 20–30% are fatal, while 30–50% of the recovered cases develop severe neurological sequelae. Specific antivirals for JEV would be of great importance, particularly in those cases where the infection has become persistent. Being indispensable for flaviviral replication, the NS2B-NS3 protease is a promising target for design of anti-flaviviral inhibitors. Contrary to related flaviviral proteases, the JEV NS2B-NS3 protease is structurally and mechanistically much less characterized. Here we aimed at establishing a straightforward procedure for cloning, expression, purification and biochemical characterization of JEV NS2B(H)-NS3pro protease. Methodology/Principal Findings The full-length sequence of JEV NS2B-NS3 genotype III strain JaOArS 982 was obtained as a synthetic gene. The sequence of NS2B(H)-NS3pro was generated by splicing by overlap extension PCR (SOE-PCR) and cloned into the pTrcHisA vector. Hexahistidine-tagged NS2B(H)-NS3pro, expressed in E. coli as soluble protein, was purified to >95% purity by a single-step immobilized metal affinity chromatography. SDS-PAGE and immunoblotting of the purified enzyme demonstrated NS2B(H)-NS3pro precursor and its autocleavage products, NS3pro and NS2B(H), as 36, 21, and 10 kDa bands, respectively. Kinetic parameters, Km and kcat, for fluorogenic protease model substrates, Boc-GRR-amc, Boc-LRR-amc, Ac-nKRR-amc, Bz-nKRR-amc, Pyr-RTKR-amc and Abz-(R)4SAG-nY-amide, were obtained using inner filter effect correction. The highest catalytic efficiency kcat/Km was found for Pyr-RTKR-amc (kcat/Km: 1962.96±85.0 M−1 s−1) and the lowest for Boc-LRR-amc (kcat/Km: 3.74±0.3 M−1 s−1). JEV NS3pro is inhibited by aprotinin but to a lesser extent than DEN and WNV NS3pro. Conclusions/Significance A simplified procedure for the cloning, overexpression and purification of the NS2B(H)-NS3pro was established which is generally applicable to other flaviviral proteases. Kinetic parameters obtained for a number of model substrates and inhibitors, are useful for the characterization of substrate specificity and eventually for the design of high-throughput assays aimed at antiviral inhibitor discovery

Microbial life in volcanic lakes

Lakes in the craters of active volcanoes and their related streams are often characterised by conditions considered extreme for life, such as high temperatures, low pH and very high concentrations of dissolved metals and minerals. Such lakes tend to be transient features whose geochemistry can change markedly over short time periods. They might also vanish completely during eruption episodes or by drainage through the crater wall or floor. These lakes and their effluent streams and springs host taxonomically and metabolically diverse microorganisms belonging in the Archaea, Bacteria, and Eucarya. In volcanic ecosystems the relation between geosphere and biosphere is particularly tight; microbial community diversity is shaped by the geochemical parameters of the lake, and by the activities of microbes interacting with the water and sediments. Sampling these lakes is often challenging, and few have even been sampled once, especially in a microbiological context. Developments in high-throughput cultivation procedures, single-cell selection techniques, and massive increases in DNA sequencing throughput, should encourage efforts to define which microbes inhabit these features and how they interact with each other and the volcano. The study of microbial communities in volcanic lake systems sheds light on possible origins of life on early Earth. Other potential outcomes include the development of microbial inocula to promote plant growth in altered or degraded soils, bioremediation of contaminated waste or land, and the discovery of enzymes or other proteins industrial or medical applications

An Agent-Based Model of Tsetse Fly Response to Seasonal Climatic Drivers: Assessing the Impact on Sleeping Sickness Transmission Rates

ackgroundThis paper presents the development of an agent-based model (ABM) to incorporate climatic drivers which affect tsetse fly (G. m. morsitans) population dynamics, and ultimately disease transmission. The model was used to gain a greater understanding of how tsetse populations fluctuate seasonally, and investigate any response observed in Trypanosoma brucei rhodesiense human African trypanosomiasis (rHAT) disease transmission, with a view to gaining a greater understanding of disease dynamics. Such an understanding is essential for the development of appropriate, well-targeted mitigation strategies in the future.MethodsThe ABM was developed to model rHAT incidence at a fine spatial scale along a 75 km transect in the Luangwa Valley, Zambia. The model incorporates climatic factors that affect pupal mortality, pupal development, birth rate, and death rate. In combination with fine scale demographic data such as ethnicity, age and gender for the human population in the region, as well as an animal census and a sample of daily routines, we create a detailed, plausible simulation model to explore tsetse population and disease transmission dynamics.ResultsThe seasonally-driven model suggests that the number of infections reported annually in the simulation is likely to be a reasonable representation of reality, taking into account the high levels of under-detection observed. Similar infection rates were observed in human (0.355 per 1000 person-years (SE = 0.013)), and cattle (0.281 per 1000 cattle-years (SE = 0.025)) populations, likely due to the sparsity of cattle close to the tsetse interface. The model suggests that immigrant tribes and school children are at greatest risk of infection, a result that derives from the bottom-up nature of the ABM and conditioning on multiple constraints. This result could not be inferred using alternative population-level modelling approaches.ConclusionsIn producing a model which models the tsetse population at a very fine resolution, we were able to analyse and evaluate specific elements of the output, such as pupal development and the progression of the teneral population, allowing the development of our understanding of the tsetse population as a whole. This is an important step in the production of a more accurate transmission model for rHAT which can, in turn, help us to gain a greater understanding of the transmission system as a whole

Measurement of the two-photon reaction γγ →π+π-π+π- at large values of Q2

The process γγ→π+π-π+π- has been investigated in reactions of the type e+e-→e+e-π+π-π+π- in the single tag mode. The range of the four momentum squared of one of the virtual photons was 0.28 GeV2/c2≦Q2≦3.6 GeV2/c2, the average being 〈Q2〉=0.92 GeV2/c2; the other photon was quasi real. The reaction is mainly described by the channels γγ→ρ0ρ0 and γγ→4π (phase space), occuring with about equal probability. The Q2-dependence of the cross section is in agreement with the ρ form factor. © 1988 Springer-Verlag