Increased diphone recognition for an Afrikaans TTS system

In this paper we discuss the implementation of an Afrikaans TTS system that is based on diphones. Using diphones makes the system flexible but presents other challenges. A previous effort to design an Afrikaans TTS system was done by SUN. They implemented a TTS system based on full words. A full word based TTS system produces more natural sounding speech than when the system is designed using other techniques. The disadvantage of using full words is that it lacks flexibility. The baseline system was build using the Festival Speech Synthesis System. Problems occurred in the baseline due to the mislabeling of diphones and the diphone index. The system was improved by manually labeling the diphones using Wavesurfer, and by changing the diphone index. Wavelength comparison tests were done on the diphone index to show how much of the diphones are recognized during synthesis. For the diphones tested results show an average improvement of 38% in the recognition of diphones compared to the baseline. These improvements improve the overall quality of the system

Affine Deligne-Lusztig varieties in affine flag varieties

This paper studies affine Deligne-Lusztig varieties in the affine flag manifold of a split group. Among other things, it proves emptiness for certain of these varieties, relates some of them to those for Levi subgroups, extends previous conjectures concerning their dimensions, and generalizes the superset method.Comment: 44 pages, 4 figures. Minor changes to font, references, and acknowledgments. Improved introduction, other improvements in exposition, and two new figures added, for a total of

Knowledge acquisition and effective socialization: the role of the psychological contract

Although studies reveal that acquiring knowledge about a new workplace during organizational socialization leads to better integration, the pathway through which this occurs is not well understood. Previous research has explored the psychological contract as an outcome of socialization. This study explores its role within the socialization process. A total of 161 organizational newcomers undertook surveys at months one and three of tenure, with data used to test a model within which four psychological contract dimensions mediate the relationship between knowledge acquisition and employee outcomes. At month one, organizational and employee promise strength mediated the relationship between knowledge and outcomes. At month three, organizational and employee promise fulfilment mediated this relationship. Findings confirm the role of the psychological contract in the socialization process and suggest that effective integration requires extensive knowledge provision and active employee knowledge acquisition. Practitioner points Acquisition of knowledge about a new work environment during the very early stages of tenure can positively affect newcomers’ attitudes and perceived employment relationships. Learning leads to mutual promises that are perceived to be stronger and more likely to be fulfilled, as well as reduced stress, greater commitment, and greater service quality behaviour. Employers should provide newcomers with information about their role, team, and organization, whilst newcomers should be encouraged to ask questions

Mécanismes psychologiques prédictifs des symptômes du TAG : intolérance à l'incertitude et pleine conscience

Le trouble d'anxiété généralisée (TAG) constitue une problématique chronique fréquemment rencontrée dans les institutions de santé mentale. Malheureusement, les traitements cliniques développés pour cette problématique sont considérés comme les moins efficaces parmi la classe des troubles anxieux. Plusieurs modèles sont développés pour mieux comprendre les mécanismes sous-jacents au TAG et pallier ce manque d'efficacité. La présente étude se penche sur deux de ces modèles afin d'étudier deux variables clés associées: l'intolérance à l'incertitude et la pleine conscience. Malgré que certains auteurs fassent état de la pertinence de développer des modèles unifiés et intégrés, peu d'études se sont penchées sur l'étude des liens pouvant unir l'intolérance à l'incertitude et la pleine conscience. La présente étude tente de préciser les liens entre la pleine conscience et les symptômes du TAG, les liens entre l'intolérance à l'incertitude et la pleine conscience et tente de démontrer le rôle de médiation de la pleine conscience dans le lien unissant l'intolérance à l'incertitude et les symptômes du TAG. Pour ce faire, 354 participants âgés entre 18 et 56 ans ont été invités à remplir une batterie de questionnaires sur les variables à l'étude. Des analyses de corrélation de Pearson, de régressions multiples et de médiation de style bootstrapping ont été conduites afin de répondre aux objectifs et hypothèses formulés. Les résultats précisent l'existence du lien entre la pleine conscience et les symptômes du TAG, le lien entre l'intolérance à l'incertitude et la pleine conscience et démontrent que la pleine conscience joue un rôle de médiation partiel dans la relation entre l'intolérance à l'incertitude et les symptômes du TAG. La discussion fait un retour sur les résultats obtenus et tente de rendre compte du lien entre les sous-dimensions de la pleine conscience et le TAG, entre l'intolérance à l'incertitude et la pleine conscience et, finalement, entre l'intolérance à l'incertitude, la pleine conscience et les symptômes du TAG. Les implications cliniques découlant de ces résultats, les limites de l'étude à considérer ainsi que les pistes pour des recherches futures sont ensuite présentées

Changes in antioxidant enzymes during sunflower seed development

International audienc

Applicability of the bulk-transfer approach to estimate evapotranspiration from boreal peatlands

In northern landscapes, peatlands are widespread and their hydrological processes are complex. Furthermore, they are typically remote, limiting the amount and accuracy of in situ measurements. This is especially the case for evapotranspiration ET, which strongly influences watershed hydrology. The objective of this paper is to demonstrate the validity of the bulk-transfer approach to estimate ET over boreal peatlands. The simplicity of the model relies on four assumptions: (i) near-neutral atmospheric conditions; (ii) wet surface; (iii) constant momentum roughness length depending on vegetation height; and (iv) constant water vapor roughness length, with the last two assumptions implying a constant water vapor transfer coefficient CE. Using eddy covariance data from three Canadian peatlands—Necopastic (James Bay, Québec), Mer Bleue (Ottawa, Ontario), and Western Peatland (Athabasca, Alberta)—this paper shows that these sites are characterized by frequent occurrences of near-neutral atmospheric conditions, especially the Necopastic site, with nearly 76% of the 30-min data segments occurring under near-neutral stratification. The analysis suggests these near-neutral conditions occur as a result of strong mechanical turbulence and weak buoyancy effects. The bulk-transfer approach gives promising results for 30-min and daily ET in terms of mean error and correlation, with performances similar to the Penman equation, without requiring net radiation data. The accuracy of the approach is likely related to the number of near-neutral periods and the elevated position of the water table, which backs up the wet surface assumption

The Sensitivity of US Wildfire Occurrence to Pre-Season Soil Moisture Conditions Across Ecosystems

It is generally accepted that year-to-year variability in moisture conditions and drought are linked with increased wildfire occurrence. However, quantifying the sensitivity of wildfire to surface moisture state at seasonal lead-times has been challenging due to the absence of a long soil moisture record with the appropriate coverage and spatial resolution for continental-scale analysis. Here we apply model simulations of surface soil moisture that numerically assimilate observations from NASA's Gravity Recovery and Climate Experiment (GRACE) mission with the US Forest Service"TM"s historical Fire-Occurrence Database over the contiguous United States. We quantify the relationships between pre-fire-season soil moisture and subsequent-year wildfire occurrence by land-cover type and produce annual probable wildfire occurrence and burned area maps at 0.25-degree resolution. Cross-validated results generally indicate a higher occurrence of smaller fires when months preceding fire season are wet, while larger fires are more frequent when soils are dry. This result is consistent with the concept of increased fuel accumulation under wet conditions in the pre-season. These results demonstrate the fundamental strength of the relationship between soil moisture and fire activity at long lead-times and are indicative of that relationship's utility for the future development of national-scale predictive capability

Turbulent Flows over Rough Permeable Beds in Mountain Rivers: Experimental Insights and Modeling

Steep mountain streams exhibit shallow waters with roughness elements such as stones and pebbles that are comparable in size to flow depth. Owing to the difficulty in measuring fluid velocities at the interface, i.e., from the rough permeable bed to the free surface, experimental results are rare although they are essential to improve models. Using a novel experimental procedure, this thesis attempts to improve predictions of the vertical structure of turbulent flows over rough permeable beds. To explore flows at the bed interface, I devised an experimental set-up where a fluid flowed over glass spheres (8 mm < dp < 14 mm) in a narrow flume (W = 6 cm) with slopes varying from 0.5 % to 8 %. The Refractive Index Matching (RIM) technique has been employed. This involves matching the refractive index of the fluid with that of the glass spheres, thereby allowing the interior of the medium to be examined and velocities to be measured by Particle Image Velocimetry (PIV). Vertical profiles are retrieved by employing the spatiotemporal double averaging method. In the course of this manuscript, flow processes are studied at the mesoscopic scale, i.e., by averaging quantities over distances ranging from 5 to 10 grain diameters. For open-channel flows over rough permeable beds, the spatial averaging procedure yields a continuous porosity profile. When applied to the Navier-Stokes equations, it produces a momentum equation with several terms including drag forces and three stresses: the turbulent, dispersive, and viscous stresses. The momentum equation was employed to devise a one dimensional (1D) model describing the vertical structure of unidirectional turbulent flow. A turbulent boundary layer over the rough bed was observed while experiments were performed at intermediate Reynolds numbers, i.e., Re = O (1000). In such conditions, viscosity plays a critical role through the van Driest damping effect. To model vertical profiles, the Darcy-Ergün equation is well suited to the prediction of friction forces in the permeable bed, i.e., in roughness and subsurface layers. Based on the \textit{Prandtl mixing length theory}, turbulent stress is predicted from a mixing length distribution that considers dispersive effects and assumes a continuous porosity profile. This alternative contrasts with most existing boundary layer models which postulate a discontinuous porosity profile for permeable or impermeable walls. Finally, hydraulic conditions collected by an Unmanned Aerial Vehicle (UAV) and classical flow resistance equations (Chézy, Keulegan, ...) were compared with profile simulations and demonstrate a good agreement between predictions and observations. It reveals the crucial role of fluid depth definition in equations in small submergence conditions. Furthermore, incipient sediment motion conditions have been estimated and compared to empirical results showing the importance of turbulence and lift force for grain entrainment. With regard to fluid dynamics, mountain streams are a case study of the larger scientific family of turbulent flows interacting with porous structures. Insights and developments acquired in the course of this thesis are likely to be transferable to other domains working with these phenomena such as flows over buildings, vegetal canopies or rough wings