A thermalization energy analysis of the threshold voltage shift in amorphous indium gallium zinc oxide thin film transistors under positive gate bias stress

Thin film transistors (TFTs) employing an amorphous indium gallium zinc oxide (a-IGZO) channel layer exhibit a positive shift in the threshold voltage under the application of positive gate bias stress (PBS). The time and temperature dependence of the threshold voltage shift was measured and analysed using the thermalization energy concept. The peak energy barrier to defect conversion is extracted to be 0.75 eV and the attempt-to-escape frequency is extracted to be 107 s−1. These values are in remarkable agreement with measurements in a-IGZO TFTs under negative gate bias illumination stress (NBIS) reported recently (Flewitt and Powell, J. Appl. Phys. 115, 134501 (2014)). This suggests that the same physical process is responsible for both PBS and NBIS, and supports the oxygen vacancy defect migration model that the authors have previously proposed.The research leading to these results has received funding from the European Community’s 7th Framework Programme under grant agreement NMP3-LA-2010-246334. Financial support of the European Commission is therefore gratefully acknowledged. The work has also received funding from FEDER through the COMPETE 2020 Programme and National Funds through FCT–Portuguese Foundation for Science and Technology under the Project No. UID/CTM/50025/2013.This is the author accepted manuscript. The final version is available from AIP Publishing via http://dx.doi.org/10.1063/1.494324

The Informal Sector In Francophone Africa: Firm Size, Productivity, And Institutions

This book is a major step towards improving the understanding of the complex reality of informal sector firms in francophone West Africa. It innovates by concentrating on informal firms rather than informal employment (as other studies do), and identifying \u27large informal\u27 sector firms whose sales rival those of large formal-sector firms but operate in ways that are similar to small informal operators. Not only is the regulatory environment facing these two types of informal firms distinct, but policies aimed at improving their productivity need to be differentiated. This study focuses on the urban informal sector in three capital cities: Dakar (Senegal), Cotonou (Benin), and Ouagadougou (Burkina Faso). The study also breaks new ground with an eclectic methodology and primary data collection. Quantitative and qualitative firm-level data were collected involving a unique and fruitful collaboration among academic researchers, government officials, the West African economic and monetary union commission, informal and formal sector business associations, and labor unions. This volume represents the culmination of a long collaboration between the Centre de Recherches Economiques Appliquees (CREA) at the University Cheikh Anta Diop of Dakar and the World Bank

Performance evaluation of various agroforestry species used in short duration improved fallows to enhance soil fertility and sorghum yields in Mali

The general soil fertility and crop yield decline constraints have guided the Malian agricultural research institute (Institut d’ Economie Rurale, IER), the Sahel Program of the World Agroforestry Centre (ICRAF) and the International Crops Research Institute for the Semi Arid Tropics (ICRISAT) to join efforts and undertake research activities aimed at mitigating the constraints in Mali. Thus, from the year 2000, 14 different trees and shrubs are being tested in improved fallow systems to find which ones perform best to replenish soils and improve crop yields. The results have (i) identified most suited species for 1 or 2 yr improved fallows, (ii) determined their impact on sorghum grain yields and (iii) documented the remnant effects of their impact on soil fertility and crop yields..

Fishers’ Perceptions and Attitudes toward Weather and Climate Information Services for Climate Change Adaptation in Senegal

Climate variability has become a major issue for vital sectors in the context of climate change. In fisheries, in particular, the effects of climate change are reflected in the decline of fishing yield and loss of lives during extreme weather events in the sea. This study analyzed the perception of climate variability and change by fisher-folks, the attitude of fisher-folks toward the weather forecast and the adoption rate of the use of the weather forecast as well as the factors determining its use in Senegal. To this end, 576 fisher-folks belonging to 41 local fishing committees along the coastal areas were surveyed and focus group discussions were organized with key informants. The adoption rate was identified using the method of the average treatment effect (ATE) and the test of independency (chi-square) was used to analyze the perceptions of and beliefs on climate change. The results showed that 96% of fisher-folks perceive the change in the climate, though the effects are differently appreciated across the coastline. The most frequently observed effects are: coastal erosion, change in wind direction, increase in extreme swells and sea level rise. Nearly half of fisher-folks confirm that they noticed these changes over the past five years. In the Southern Coast in particular, 40% of fisher-folks stated that these changes happened 10 years ago. This statement is confirmed by the qualitative data. More than 90% of the respondents ascertain the weather forecast before going to fish, 63% regularly receive the weather forecast and 53% avoid going to sea during extreme events. In addition, the results showed that if the weather forecast was made accessible to the majority of fisher-folks, more than 83% would avoid going to sea during periods of extreme weather extreme events, thus reducing significantly the number of fatalities. The best way to protect the fisher-folks from the harmful effects of climate change is to ensure large-scale access to and use of accurate weather forecasts

Emergence of the OXA-23 carbapenemase-encoding gene in multidrug-resistant Acinetobacter baumannii clinical isolates from the Principal Hospital of Dakar, Senegal

International audienc

Acute febrile illness and influenza disease burden in a rural cohort dedicated to malaria in Senegal, 2012-2013

Background African populations are considered to be particularly vulnerable to fever illnesses, including malaria, and acute respiratory disease, owing to limited resources and overcrowding. However, the overall burden of influenza in this context is poorly defined and incidence data for African countries are scarce. We therefore studied the fever syndrome incidence and more specifically influenza incidence in a cohort of inhabitants of Dielmo and Ndiop in Sokone district, Senegal. Methods Daily febrile-illness data were prospectively obtained from January 2012 to December 2013 from the cohort of the villages of Dielmo and Ndiop, initially dedicated to the study of malaria. Nasopharyngeal swabs were collected from, and malaria diagnosis tests (thick blood smears) carried out on, every febrile individual during clinical visits; reverse transcriptase- polymerase chain reaction was used to identify influenza viruses in the samples. Binomial negative regression analysis was used to study the relationship between the monthly incidence rate and various covariates. Results In Dielmo and Ndiop, the incidence ofmalaria has decreased, but fever syndromes remain frequent. Among the 1036 inhabitants included in the cohort, a total of 1,129 episodes of fever were reported. Influenza was present all year round with peaks in October-December 2012 and August 2013. The fever, ILI and influenza incidence density rates differed significantly between age groups. At both sites, the adjusted incidence relative risks for fever syndromes and ILI were significantly higher in the [6-24 months) than other age groups: 7.3 (95% CI: [5.7-9.3]) and 16.1 (95% CI: [11.1-23.3]) respectively. The adjusted incidence relative risk for influenza was significantly higher for the [0-6 months) than other age groups: 9.9 (95% CI: [2.9-33.6]). At both sites, incidence density rates were lowest among adults > = 50 years. Conclusions In this rural setting in Senegal, influenza was most frequent among the youngest children. Preventive strategies targeting this population should be implemented