Phonetic Drift in Fricatives and the Effects of L2 Experience on L1 Phonetic Categories

Previous research has shown that L2 learners immersed in a target language environment exhibit phonetic drift in L1 category boundaries along VOT （Chang, 2002, 2010; Tice & Woodley, 2012） and vowel formant （Guion, 2003） dimensions, which subsides after an extended duration of immersion. This study investigates the articulation of sibilant fricatives in Japanese and in English by three groups of bilinguals – a） late bilinguals who have studied abroad; b） late bilinguals with no experience abroad; c） early （simultaneous） bilinguals – to determine whether they differ from one another in distinguishing post-alveolar sibilants of English, [ʃ], and Japanese, [㷡], and whether there is evidence among late bilinguals of phonetic drift in the alveolar sibilant [s] common to both languages under pressure from the novel English post-alveolar.Participants produced real words containing each of the test segments before a high or a low vowel in four blocks, two in English and two in Japanese both in isolation and embedded within a carrier phrase. Productions were recorded and submitted to acoustic analysis. Measurements of spectral Center of Gravity (Hanulíková and Weber, 2010) revealed differences between the two languages only among late bilinguals with no study abroad experience. Without intensive immersion experience, these participants were expected to exhibit no evidence of phonetic drift; however, the pool from which they were recruited was comprised of Japanese university students majoring in linguistics with coursework in English phonetics. We therefore speculate that phonetic drift may not arise solely from intensive exposure in an immersion environment but from heightened perceptual awareness brought about through acquired metalinguistic knowledge as well. It is surmised that any experience of phonetic drift that the other two groups may have had must already have subsided by the time of testing given the extent of their exposure experience

Inter-comparison of gauge-corrected global satellite rainfall estimates and their applicability for effective water resource management in a transboundary river basin: the case of the Meghna river basin

The Meghna River basin is a transboundary basin that lies in Bangladesh (~40%) and India (~60%). Due to its terrain structure, the Bangladesh portion of the basin experiences frequent floods that cause severe human and economic losses. Bangladesh, as the downstream nation in the basin, faces challenges in receiving hydro-meteorological and water use data from India for effective water resource management. To address such issue, satellite rainfall products are recognized as an alternative. However, they are affected by biases and, thus, must be calibrated and verified using ground observations. This research compares the performance of four widely available gauge-adjusted satellite rainfall products (GSRPs) against ground rainfall observations in the Meghna basin within Bangladesh. Further biases in the GSRPs are then identified. The GSRPs have both similarities and differences in terms of producing biases. To maximize the usage of the GSRPs and to further improve their accuracy, several bias correction and merging techniques are applied to correct them. Correction factors and merging weights are calculated at the local gauge stations and are spatially distributed by adopting an interpolation method to improve the GSRPs, both inside and outside Bangladesh. Of the four bias correction methods, modified linear correction (MLC) has performed better, and partially removed the GSRPs’ systematic biases. In addition, of the three merging techniques, inverse error-variance weighting (IEVW) has provided better results than the individual GSRPs and removed significantly more biases than the MLC correction method for three of the five validation stations, whereas the two other stations that experienced heavy rainfall events, showed better results for the MLC method. Hence, the combined use of IEVW merging and MLC correction is explored. The combined method has provided the best results, thus creating an improved dataset. The applicability of this dataset is then investigated using a hydrological model to simulated streamflows at two critical locations. The results show that the dataset reproduces the hydrological responses of the basin well, as compared with the observed streamflows. Together, these results indicate that the improved dataset can overcome the limitations of poor data availability in the basin and can serve as a reference rainfall dataset for wide range of applications (e.g., flood modelling and forecasting, irrigation planning, damage and risk assessment, and climate change adaptation planning). In addition, the proposed methodology of creating a reference rainfall dataset based on the GSRPs could also be applicable to other poorly-gauged and inaccessible transboundary river basins, thus providing reliable rainfall information and effective water resource management for sustainable development

Malt1-Induced Cleavage of Regnase-1 in CD4+ Helper T Cells Regulates Immune Activation

SummaryRegnase-1 (also known as Zc3h12a and MCPIP1) is an RNase that destabilizes a set of mRNAs, including Il6 and Il12b, through cleavage of their 3′ UTRs. Although Regnase-1 inactivation leads to development of an autoimmune disease characterized by T cell activation and hyperimmunoglobulinemia in mice, the mechanism of Regnase-1-mediated immune regulation has remained unclear. We show that Regnase-1 is essential for preventing aberrant effector CD4+ T cell generation cell autonomously. Moreover, in T cells, Regnase-1 regulates the mRNAs of a set of genes, including c-Rel, Ox40, and Il2, through cleavage of their 3′ UTRs. Interestingly, T cell receptor (TCR) stimulation leads to cleavage of Regnase-1 at R111 by Malt1/paracaspase, freeing T cells from Regnase-1-mediated suppression. Furthermore, Malt1 protease activity is critical for controlling the mRNA stability of T cell effector genes. Collectively, these results indicate that dynamic control of Regnase-1 expression in T cells is critical for controlling T cell activation

Disaster Risks Research and Assessment to Promote Risk Reduction and Management

Natural hazard events lead to disasters when the events interact with exposed and vulnerable physical and social systems. Despite significant progress in scientific understanding of physical phenomena leading to natural hazards as well as of vulnerability and exposure, disaster losses due to natural events do not show a tendency to decrease. This tendency is associated with many factors including increase in populations and assets at risk as well as in frequency and/or magnitude of natural events, especially those related to hydro-meteorological and climatic hazards. But essentially disaster losses increase because some of the elements of the multidimensional dynamic disaster risk system are not accounted for risk assessments. A comprehensive integrated system analysis and periodic assessment of disaster risks at any scale, from local to global, based on knowledge and data/information accumulated so far, are essential scientific tools that can assist in recognition and reduction of disaster risks. This paper reviews and synthesizes the knowledge of natural hazards, vulnerabilities, and disaster risks and aims to highlight potential contributions of science to disaster risk reduction (DRR) in order to provide policy-makers with the knowledge necessary to assist disaster risk mitigation and disaster risk management (DRM)

Regional water exchange for drought alleviation

November 1974.Includes bibliographical references