Gaze-dependent topography in human posterior parietal cortex.

The brain must convert retinal coordinates into those required for directing an effector. One prominent theory holds that, through a combination of visual and motor/proprioceptive information, head-/body-centered representations are computed within the posterior parietal cortex (PPC). An alternative theory, supported by recent visual and saccade functional magnetic resonance imaging (fMRI) topographic mapping studies, suggests that PPC neurons provide a retinal/eye-centered coordinate system, in which the coding of a visual stimulus location and/or intended saccade endpoints should remain unaffected by changes in gaze position. To distinguish between a retinal/eye-centered and a head-/body-centered coordinate system, we measured how gaze direction affected the representation of visual space in the parietal cortex using fMRI. Subjects performed memory-guided saccades from a central starting point to locations “around the clock.” Starting points varied between left, central, and right gaze relative to the head-/body midline. We found that memory-guided saccadotopic maps throughout the PPC showed spatial reorganization with very subtle changes in starting gaze position, despite constant retinal input and eye movement metrics. Such a systematic shift is inconsistent with models arguing for a retinal/eye-centered coordinate system in the PPC, but it is consistent with head-/body-centered coordinate representations

Are households’ poverty levels in Mekong Delta of Vietnam affected by access to credit?

This paper investigates the impact of access to formal credit on household poverty in Mekong Delta (MD) – Vietnam. The analysis is based on some indicators of household poverty such as households’ total assets, educational costs, healthcare costs, food consumption, non-farm expenses, off-farm expenses and total income. Based on the given indicators, a comparison is made between borrowers and non-borrowers in a sample of 325 households using the Matching Methods. The findings suggest that the borrowers are better off in education expenditure, healthcare expenses, and total income than those of non-borrowers. The results show that access to formal credit is likely to reduce poverty levels among rural households in Mekong Delta

Determinants of household access to formal credit in the rural areas of the Mekong Delta, Vietnam

This paper investigates the factors affecting the access of rural individual and group-based households to formal credit in the Mekong Delta (MD), Vietnam. Poverty levels in the Mekong Delta have declined significantly over the last decades, but in the rural areas they remain significant. If it is assumed that access to credit is a suitable vehicle for poverty alleviation, it is necessary to assess the way households decide on borrowing. This paper identifies the determinants of the decision to borrow and of the amount that is borrowed by using the double hurdle model and the Heckman selection model. Data used in this paper were obtained from a survey of 325 rural households, conducted between May and October 2009. The results indicate that household capital endowments, marital status, family size, distance to the market centre, and location affect both the probability and the amount of asking for credit

Metal complex catalysed C-X (X = S, O and N) bond formation

This thesis describes the catalysed addition of X-H bonds (X = S, O and N) to alkynes using a range of novel rhodium(I) and iridium(I) complexes containing hybrid bidentate phosphine-pyrazolyl, phosphine-imidazolyl and phosphine-N heterocyclic carbene (NHC) donor ligands. The synthesis of novel bidentate phosphine-pyrazolyl, phosphine-imidazolyl (P-N) and phosphine-NHC (PC) donor ligands and their cationic and neutral rhodium(I) and iridium(I) complexes [M(P N)(COD)]BPh4, [M(PC)(COD)]BPh4, [Ir(P-N)(CO)2]BPh4 and [M(P-N)(CO)Cl] were successfully performed. An unusual five coordinate iridium complex with phosphine-NHC ligands [Ir(PC)(COD)(CO)]BPh4 was also obtained. Seventeen single crystal X-ray structures of these new complexes were determined. A range of these novel rhodium and iridium complexes were effective as catalysts for the addition of thiophenol to a variety of alkynes. Iridium complexes were more effective than rhodium analogues. Cationic complexes were more effective than neutral complexes. Complexes with hybrid phosphine-nitrogen donor were more effective than complexes containing bidentate nitrogen donor ligands. An atom-economical, efficient method for the synthesis of cyclic acetals and bicyclic O,O-acetals was successfully developed based on the catalysed hydroalkoxylation. Readily prepared terminal and non-terminal alkyne diols were cyclised into bicyclic O,O-acetals in quantitative conversions in most cases. The efficiency of a range of rhodium and iridium complexes containing bidentate P-N and PC donor ligands as catalysts for the cyclisation of 4-pentyn-1-amine to 2-methyl-1-pyrroline varied significantly. The cationic iridium complexes with the bidentate phosphine-pyrazolyl ligands, [Ir(R2PyP)(COD)]BPh4 (2.39-2.42) were extremely efficient as catalysts for this transformation. Increasing the size of the substituent on or adjacent to the donor led to improvement in catalytic activity of the corresponding metal complexes. The mechanism of the catalysed hydroalkoxylation was proposed to proceed by the initial activation of the alkyne via π coordination to the metal centre. The π binding of both aliphatic and aromatic alkynes to [Ir(PyP)(CO)2]BPh4 (2.44) was observed by low temperature NMR and no reaction between 2.44 and alcohols was observed. In contrast, the facility in which thiol and amine oxidatively added to 2.44 led the proposal that in the hydrothiolation and hydroamination reaction, the catalytic cycle commences with the activation of the X-H bond (X = S, N) by an oxidative addition process

Modeling of Electromagnetic Systems by Coupling of Subproblems – Application to Thin Shell Finite Element Magnetic Models

The direct application of the finite element method to realistic electromagnetic problems is challenging, especially when modeling structures with thin conductive and/or magnetic parts. This work presents a subproblem method for correcting the inaccuracies inherent to classical thin shell models, and to efficiently handle geometrical and material variations in parametric studies

EFL Teachers’ Challenges in Maximizing Classroom Interaction

Classroom interaction plays a significant role in facilitating learners’ development of communicative competence by making input more comprehensible to learners and maximizing the language input to become learners’ intake (Krashen, 1987; Swain, 1995; Long, 1996; Gass, 1997; Lucha & Berhanu, 2015). Results of related studies reveal a low level of communicative competence of many Vietnamese learners of English, which could result from the lack of opportunities for interaction in Vietnamese EFL classes (Hiep, 2007; Ngoc, 2010; Canh, 2011; Ngan, 2013; Tuyen, 2013; Duy, 2014). This study aims to investigate EFL teachers’ challenges in maximizing classroom interaction. A questionnaire was administered to 50 lecturers from sixteen colleges and universities in the Mekong Delta of Viet Nam to examine their challenges in maximizing classroom interaction. The results of the study show that Vietnamese EFL lecturers encountered challenges related to physical factors or learning conditions, learners’ factors and teachers’ factors as well. Learner-related factors showed to be most significant challenge in this study

Are households’ poverty levels in Mekong Delta of Vietnam affected by access to credit?

This paper investigates the impact of access to formal credit on household poverty in Mekong Delta (MD) – Vietnam. The analysis is based on some indicators of household poverty such as households’ total assets, educational costs, healthcare costs, food consumption, non-farm expenses, off-farm expenses and total income. Based on the given indicators, a comparison is made between borrowers and non-borrowers in a sample of 325 households using the Matching Methods. The findings suggest that the borrowers are better off in education expenditure, healthcare expenses, and total income than those of non-borrowers. The results show that access to formal credit is likely to reduce poverty levels among rural households in Mekong Delta