Learner perceptions of demotivators in the English as a foreign language (EFL) classroom: Conceptual framework, scale development, and tentative underlying cause analysis

Notwithstanding the negative influence of demotivation on student learning outcomes, prior research in EFL demotivation suffers from the lack of generally agreed-upon conceptual understanding, which hampers scale development. The present series of studies sought to explore the ideas of demotivation and describe the development of the Learner Perception of Demotivators Scale (LPDS) both conceptually and psychometrically. In Study 1 (N = 295), an exploratory factor analysis offered preliminary support for a factor structure comprising three dimensions: negative teacher behavior, loss of task value, and low expectancy for success. In Study 2 (N = 320), the proposed factor structure was further corroborated through confirmatory factor analysis, and its validity was documented by means of correlating with academic performance, self-efficacy, and mindset. A second-order factor model was tested to investigate whether a set of demotivating factors load on an overall construct that may be termed “Demotivator”. Whereas the model fit confirmed a wellitting second-order model with post hoc model adjustment, one low first-order loading (negative teacher behavior) does not seem to support “Demotivator” as a higher order construct comprising three subdimensions. Furthermore, the LPDS demonstrated evidence of configural, metric, scalar, and residual invariance across gender, suggesting the same underlying construct is measured across gender groups. Contrary to the findings in motivation research, loss of task value was a stronger predictor of performance than low expectancy for success. Further, in Study 3 (N =320), loss of task value distinguished extremely motivated EFL learners from ordinary ones, offering tentative evidence for the reason behind demotivation in EFL learning. The unique role of task value found in Study 2 and Study 3 gave insights into the hypothetical construct of “demotivation”. It was also examined in the context of East Asian culture. By establishing a nomological network (academic performance, self-efficacy, and mindset), the current study provided a lawful pattern of interrelationships that exists between the hypothetical construct (demotivation) and observable attributes (e.g., academic performance) and that guides researcher for future L2 studies. More implications and limitations for future studies are discussed

Mutagenesis induced by the tumor microenvironment: implications of increased DNA damage and diminished DNA repair

Tumors are characterized by microenvironmental heterogeneity, with regions of hypoxia, low pH, and nutrient deprivation. It has been proposed that such conditions may be an important factor contributing to cancer genetic instability. Using a chromosomally based lambda phage shuttle vector as a mutation reporter, we show that growth of cells in hypoxia and/or at low pH results in elevated mutation frequencies in two different reporter genes. To elucidate the mechanism of the tumor microenvironment-induced genetic instability, we first measured the production of DNA damage upon hypoxia and re-oxygenation in culture. We found that under such conditions, the intracellular level of a premutagenic lesion, 8-oxo-dG, was increased by 2- to 3-fold, consistent with the frequent G to T transversions observed among the hypoxia-induced mutation spectrum. We next examined the effect of the tumor microenvironment on two important cellular DNA repair pathways, i.e., the nucleotide excision repair (NER) and the mismatch repair (MMR) pathways. Using an assay for repair based on host cell reactivation of UV-damaged plasmid DNA, cells exposed to hypoxia and low pH were found to have a diminished capacity for DNA NER compared to control cells grown under standard conditions. Furthermore, the expression of the MMR gene, Mlh1, was specifically reduced under hypoxia, along with secondary decrease in Pms2 protein. On a functional level, instability of simple dinucleotide repeats, a hallmark of MMR deficiency, was detected in hypoxic cells. Taken together, our work suggests that the tumor microenvironment may lead to conditions that either cause DNA damage or compromise DNA repair processes, and consequently contribute to mutagenesis and genomic instability. This may constitute a fundamental mechanism of tumor progression in vivo

The NGC 4013 tale: a pseudo-bulged, late-type spiral shaped by a major merger

Many spiral galaxy haloes show stellar streams with various morphologies when observed with deep images. The origin of these tidal features is discussed, either coming from a satellite infall or caused by residuals of an ancient, gas-rich major merger. By modelling the formation of the peculiar features observed in the NGC 4013 halo, we investigate their origin. By using GADGET -2 with implemented gas cooling, star formation, and feedback, we have modelled the overall NGC 4013 galaxy and its associated halo features. A gas-rich major merger occurring 2.7-4.6 Gyr ago succeeds in reproducing the NGC 4013 galaxy properties, including all the faint stellar features, strong gas warp, boxy-shaped halo and vertical 3.6 mum luminosity distribution. High gas fractions in the progenitors are sufficient to reproduce the observed thin and thick discs, with a small bulge fraction, as observed. A major merger is able to reproduce the overall NGC 4013 system, including the warp strength, the red colour and the high stellar mass density of the loop, while a minor merger model cannot. Because the gas-rich model suffices to create a pseudo-bulge with a small fraction of the light, NGC 4013 is perhaps the archetype of a late-type galaxy formed by a relatively recent merger. Then late type, pseudo-bulge spirals are not mandatorily made through secular evolution, and the NGC 4013 properties also illustrate that strong warps in isolated galaxies may well occur at a late phase of a gas-rich major merger.Comment: 11 pages,9 figures,accepted for publication in MNRA

Learning a Hybrid Architecture for Sequence Regression and Annotation

When learning a hidden Markov model (HMM), sequen- tial observations can often be complemented by real-valued summary response variables generated from the path of hid- den states. Such settings arise in numerous domains, includ- ing many applications in biology, like motif discovery and genome annotation. In this paper, we present a flexible frame- work for jointly modeling both latent sequence features and the functional mapping that relates the summary response variables to the hidden state sequence. The algorithm is com- patible with a rich set of mapping functions. Results show that the availability of additional continuous response vari- ables can simultaneously improve the annotation of the se- quential observations and yield good prediction performance in both synthetic data and real-world datasets.Comment: AAAI 201