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Understanding the IELTS washback on learning in English as a Foreign Language (EFL) in higher education contexts remains limited. To fill in this research gap, this study investigated washback effects of the International English Language Testing System (hereafter called IELTS) as an English language proficiency exit test for final-year English majors in Central Vietnam from the perspectives of student psychology and learning behaviors by combining Hughes' (1993) and Shih's (2007) washback models to identify the specific washback mechanisms formed by the test factors related to the IELTS. Using a sample of 282 final-year English majors responding to an online questionnaire at a Central Vietnamese University, the factor structures for IELTS washback on learning from test factors were determined by Exploratory Factor Analysis and confirmed by Confirmatory Factor Analysis. Data analyses involved descriptive statistics, Pearson correlation, and multiple linear regression analyses. The study revealed that the IELTS exerted both positive and negative washback on the student psychology and learning behaviors. The students perceived the IELTS as difficult to achieve the required score. They also perceived IELTS as high stakes with various utility values for different aspects of life. The washback mechanisms showed that the test factors exerted effects on the IELTS washback formation in different manners and to different degrees.

Combining Bachman's (1990) conceptualization of content validity with Messick's (1989) unifying model of construct validity, this study attempted to fill the gap in researching content validation in the context of a university reading achievement test by (a) examining traditional content validity evidence and (b) analyzing the test scores to either back-up or rebut the evidence and explore the construct of the underlying test structure. On a sample of 477 third-year English-majored test takers at a Central Vietnamese University (CVU), the study was conducted in the pre-test stage where the test content was compared with the test specification and the post-test stage where the test scores were processed via Rasch and CFA competing model analyses. Results showed that while content relevance was satisfactory and the test construct was to a large extent not threatened by construct-irrelevant variance, content coverage of the test remained problematic with instances of construct underrepresentation. Moreover, the study supported the one-factor model of general reading ability as the underlying structure of the reading achievement test over the correlated three sub-skill and higher-order factor models. The study bears implications for both test writers in designing and test takers in performing the L2 reading test.

Aortoenteric fistula is one of the uncommon emergencies and is challenging to navigate for diagnostic testing. Here, we present a clinical case of an aortoduodenal fistula with primary etiology. A 73-year-old female patient with a history of hypertension was admitted to the hospital because of a 1-day history of melena. Ultrasound showed an abdominal aortic aneurysm sized (33 × 46) mm and a hematoma on the wall of the aorta. The patient underwent a gastrointestinal endoscopy with no bleeding point detected. However, the patient suddenly fell into a hemorrhagic shock on day 3 of admission. We rapidly performed fluid resuscitation, blood transfusion, a second gastrointestinal endoscopy, and a computed tomography scan of the abdomen with contrast injection that revealed a fistula from the abdominal aorta into the second segment of the duodenum. The patient was indicated for urgent endovascular aortic repair. Although this technique was successful with 3 abdominal aortic stents, the patient died due to multiorgan failure. Delayed diagnosis is the root cause of primary aortoduodenal fistula treatment failure, so it is important for clinicians to keep aortoduodenal fistula in mind as a possible cause of gastrointestinal bleeding in any patient.

Microbial exopolysaccharides (EPSs) are receiving growing interest today, owing to their diversity in chemical structure and source, multiple functions, and immense potential applications in many food and non-food industries. Their health-promoting benefits for humans deserve particular attention because of their various biological activities and physiological functions. The aim of this paper is to provide a comprehensive review of microbial EPSs, covering (1) their chemical and biochemical diversity, including composition, biosynthesis, and bacterial sources belonging mainly to lactic acid bacteria (LAB) or probiotics; (2) their technological and analytical aspects, especially their production mode and characterization; (3) their biological and physiological aspects based on their activities and functions; and (4) their current and future uses in medical and pharmaceutical fields, particularly for their prebiotic, anticancer, and immunobiotic properties, as well as their applications in other industrial and agricultural sectors. [ABSTRACT FROM AUTHOR]

Virtual reality (VR) has been adopted in various fields such as entertainment, education, healthcare, and the military, due to its ability to provide an immersive experience to users. However, 360° images, one of the main components in VR systems, have bulky sizes and thus require effective transmitting and rendering solutions. One of the potential solutions is to use foveated technologies, that take advantage of the foveation feature of the human eyes. Foveated technologies can significantly reduce the data required for transmission and computation complexity in rendering. However, understanding the impact of foveated 360° images on human quality perception is still limited. This paper addresses the above problems by proposing an accurate machine-learning-based quality assessment model for foveated 360° images. The proposed model is proven to outperform the three cutting-edge machine-learning-based models, which apply deep learning techniques and 25 traditional-metric-based models (or analytical-function-based-models), which utilize analytical functions. It is also expected that our model helps to evaluate and improve 360° content streaming and rendering solutions to further reduce data sizes while ensuring user experience. Also, this model could be used as a building block to construct quality assessment methods for 360° videos, that are reserved for our future work. The source code is available at https://github.com/telagment/FoVGCN.

Study of structural inhomogeneities in zeolites is important but limited by conventional techniques. Here the authors employ in situ free-electron-laser-based time-resolved coherent X-ray diffraction imaging to visualize the effect of these inhomogeneities during catalytic deoxygenation of NOx.

The paper investigates the optimal strategy of a small open economy receiving foreign direct investment (FDI) in an optimal growth context. We prove that no domestic firm can enter the new industry when the multinational enterprise's productivity or the fixed entry cost is high. Nevertheless, the host country's investment stock converges to a higher steady state than an economy without FDI. A domestic firm enters the new industry if its productivity is high enough. Moreover, the domestic firm can dominate or even eliminate its foreign counterpart. [ABSTRACT FROM AUTHOR]