Endogenous Fiscal Policies, Environmental Quality, and Status-Seeking Behavior.

This paper analyzes endogenous fiscal policy and public decision in an endogenous growth model where agents care about social status and environmental quality. The quest for a higher status is assimilated to a preference for capital wealth. The government uses income tax to finance infrastructure and environmental protection, and maximizes individual welfare. We find that accounting for preferences for social status and environmental quality may lead to an allocation of tax revenue in favor of cleanup effort to the detriment of infrastructure. It does not necessary have a negative impact on growth. Status seeking can however harm economic growth and environmental quality when its motive is important enough. Finally, we show that economic growth is consistent with environmental preservation but is not necessarily welfare-improving as in the case of absence of status-seeking behavior.Endogenous policy; endogenous growth; environmental quality; status-seeking; public expenditure; Wagner's law.

Online learning negotiation: Native-speaker versus nonnative speaker teachers and Vietnamese EFL learners

Online English language teaching can now be facilitated by communication technology, which allows easy access to interaction with native speakers. Nevertheless, this industry subscribes to an assumption that native speaker English teachers (NESTs) are the gold standard of language whereas the non-native speaker English teachers (NNESTs) are inferior educators (Walkinshaw & Duong, 2014). Rare research has provided evidence of the negotiation produced by NESTs versus NNESTs with EFL learners online and its impact on the learners’ output. Thus, the current study narrows this empirical gap. Drawing upon a database of 30 five-minute interaction sessions between 30 teachers (15 NESTs and 15 NNESTs) and 30 basic level Vietnamese EFL adult learners, the study revealed similar negotiation of meaning functions as reported in previous research. However, the NESTs used more elaboration while the NNESTs used more confirmation checks, clarification requests, and reply clarification. Qualitative analysis further indicated that the NNESTs provided more productive support, encouraging the learners’ output, than the NESTs did. This implies that although online voice interaction creates an environment for EFL learners to practice, language educators and teachers, regardless of status, should heed how to handle it so that online learners can benefit from both comprehensible input and opportunities for pushed output

The Accuracy of Endodontic Length Measurement Using Cone-beam Computed Tomography in Comparison with Electronic Apex Locators

Introduction: The aim of this in vitro study was to evaluate the accuracy of cone-beam computed tomography (CBCT) and two electronic apex locators (EALs) when measuring the actual length of root canals. Methods and Materials: One hundred and eighty four root canals in 135 extracted anterior and posterior permanent teeth were studied. Root canal curvatures were analyzed on CBCT images, and root canals with curvatures less than 70º were chosen. Root canal length measurements were performed using CBCT, ProPex Pixi, E-Pex Pro, and the actual length (AL). The percentages of the measurements in the range of ±0.5 mm to the AL were compared using Fisher’s Exact test. The ICC indices and Bland-Altman plots were used to display the agreement of three devices with the AL measurements. The statistical significance was set at P<0.05. Results: The accuracies of E-Pex Pro and ProPex Pixi (87.5% and 82.6%, respectively) were better than that of CBCT (71.7%) (P<0.05). Conclusion: This in vitro study showed that although the accuracies of the two EALs were at high level, there was no device that had an agreement with the actual root canal length measurementKeywords:Cone-beam Computed Tomography; Electronic Apex Locator; Endodontics; Root Canal Length; Root Canal Therapy 

Income distribution dynamics across European regions

We use two datasets to study the convergence process across European regions. Relying on Quah (1966a,1997), we examine the dynamics of income distribution and find evidence of polarization whatever the time horizon considered. Regions whose incomes were close together at an initial period transit subsequently to widely different income levels.distribution dynamics

AN EFFECTIVE REVERSIBLE DATA HIDING METHOD BASED ON PIXEL-VALUE-ORDERING

This paper presents a new effective reversible data hiding method based on pixel-value-ordering (iGePVO-K) which is improvement of a recent GePVO-K method that recently is considered as a PVO-used method having highest embedding capacity. In comparison with GePVO-K method, iGePVO-K has the following advantages. First, the embedding capacity of the new method is higher than that of GePVO-K method by using data embedding formulas reasonably and reducing the location map size. Second, for embedding data, in the new method, each pixel value is modified at most by one, while in GePVO-K method, each pixel value may be modified by two. In fact, in the GePVO-K method, the largest pixels are modified by two for embedding bits 1 and by one for bits 0. This is also true for the smallest pixels. Meanwhile, in the proposed method, the largest pixels are modified by one for embedding bits 1 and are unchanged if embedding bits 0. Therefore, the stego-image quality in proposed method is better than that in GePVO-K method. Theoretical analysis and experiment results show that the proposed method has higher embedding capacity and better stego image quality than GePVO-K method

Induced systemic resistance against rice grassy stunt virus – a promising field for ecological rice production: Research article

Most rice protection methods have currently used toxic chemicals to control pathogens and pests, which leads to environmental pollution. Systemic acquired resistance (SAR) taking advantage of natural defence reaction of plants could be proposed as an alternative, ecologically friendly approach for plant protection. Its application into rice production could minimize the chemicals quantity used and could contribute to the decrease of environmental pollution and the development of sustainable agriculture. The research was conducted to select the most effective chemical and suitable method to improve the health of rice plants infected by grassy stunt disease in net-house of Can Tho University. SAR chemicals were used at very low concentrations (in mM). Results showed that the height of rice plants treated with SAR chemicals was higher than that of plants untreated. Besides, the number of diseased plants was reduced and the ratio of firm grain and yield increased when plants were applied by SAR. Among the used substances, oxalic acid provided the best systemic acquired resistance. With oxalic acid, seed soaking was better than seed coating in systemic acquired resistance against rice grassy stunt disease.Hầu hết các phương pháp sản xuất lúa hiện nay đều sử dụng các hóa chất độc hại trong việc phòng trừ bệnh và côn trùng gây hại, nên dẫn đến ô nhiễm môi trường. Kích thích tính kháng lưu dẫn giúp kích hoạt cơ chế tự nhiên kháng bệnh của cây có thể là giải pháp bảo vệ thực vật thay thế an toàn với môi trường. Việc ứng dụng tiến bộ này vào trong sản xuất lúa có thể làm giảm lượng hóa chất sử dụng, đóng góp vào việc giảm thiểu ô nhiễm môi trường và sự phát triển của một nền nông nghiệp bền vững. Nghiên cứu đã được thực hiện tại nhà lưới trường Đại học Cần Thơ để tuyển chọn hóa chất và phương pháp sử dụng hóa chất để tăng cường sức khỏe giúp cây lúa vượt qua bệnh vàng lùn. Hóa chất kích kháng được sử dụng ở một nồng độ rất thấp (đơn vị là mM). Kết quả cho thấy chiều cao cây lúa khi xử lý chất kích kháng tốt hơn so đối chứng không xử lý. Bên cạnh đó, số cây lúa nhiễm bệnh giảm, tỉ lệ hạt chắc và năng suất tăng khi cây lúa được xử lý với chất kích kháng. Trong số các chất kích kháng đã sử dụng, acid oxalic cho hiệu quả vượt trội. Với chất acid oxalic, phương pháp ngâm hạt cho hiệu quả kích kháng tốt hơn phương pháp áo hạt

Coderivatives at infinity of set-valued mappings

In this paper, the concept of coderivatives at infinity of set-valued mappings is introduced. Well-posedness properties at infinity of set-valued mappings as well as Mordukhovich's criterion at infinity are established. Fermat's rule at infinity in set-valued optimization is also provided. The obtained results, which give new information even in the classical cases of smooth single-valued mappings, provide complete characterizations of the properties under consideration in the setting at infinity of set-valued mappings