Use and Improvement of Remote Sensing and Geospatial Technologies in Support of Crop Area and Yield Estimations in the West African Sahel

In arid and semi-arid West Africa, agricultural production and regional food security depend largely on small-scale subsistence farming and rainfed crops, both of which are vulnerable to climate variability and drought. Efforts made to improve crop monitoring and our ability to estimate crop production (areas planted and yield estimations by crop type) in the major agricultural zones of the region are critical paths for minimizing climate risks and to support food security planning. The main objective of this dissertation research was to contribute to these efforts using remote sensing technologies. In this regard, the first analysis documented the low reliability of existing land cover products for cropland area estimation (Chapter 2). Then two satellite remote sensing-based datasets were developed that 1) accurately map cropland areas in the five countries of Sahelian West Africa (Senegal, Mauritania, Mali, Burkina Faso and Niger; Chapter 3), and 2) focus on the country of Mali to identify the location and prevalence of the major subsistence crops (millet, sorghum, maize and non-irrigated rice; Chapter 4). The regional cropland area product is distributed as the West African Sahel Cropland area at 30 m (WASC30). The development of the new dataset involved high density training data (380,000 samples) developed by USGS in collaboration with CILSS for training about 200 locally optimized random forest (RF) classifiers using Landsat 8 surface reflectances and vegetation indices and the Google Earth Engine platform. WASC30 greatly improves earlier estimates through inclusion of cropland information for both rainfed and irrigated areas mapped with a class-specific accuracy of 79% across the West Africa Sahel. Used as a mask in crop monitoring systems, the new cropland area data could bring critical insights by reducing uncertainties in xv identification of croplands as crop growth condition metrics are extracted. WASC30 allowed us to derive detailed statistics on cultivated areas in the Sahel, at country and agroclimatic scales. Intensive agricultural zones were highlighted as well. The second dataset, mapping crop types for the country of Mali, is meant to separate signals of different crop types for improved crop yield estimation. The crop type map was used to derive detailed agricultural statistics (e.g. acreage by crop types, spatial distribution) at finer administrative scales than has previously been possible. The crop fraction information by crop type extracted from the map, gives additional details on farmers preferences by regions, and the natural adaptability of different crop types. The final analysis of this dissertation explores the use of ensemble machine learning techniques to predict maize yield in Mali (Chapter 5). Climate data (precipitation and temperature), and vegetation indices (Normalized Difference Vegetation Index, NDVI, the Enhanced Vegetation Index, EVI, and the Normalized Difference Water Index, NDWI) are used as predictors, while actual yields collected in 2017 by the Malian Ministry of Agriculture are the reference data. Random forest presented better predictive performance as compared to boosted regression trees (BRT). Results showed that climate variables have more predictive power for maize yield compared to vegetation indices. Among vegetation indices, the NDWI appeared to be the most influential predictor, maybe because of water requirement of maize and the sensitivity of this index to water in semi-arid regions. Tested with two different independent datasets, one constituted by 20% of the reference information, and another including observed yields for year 2018 (a one-year-left analysis), maize yield predictions were promising for year 2017 (RMSE = 362 kg/ha), but showed higher error for 2018 (RMSE = 707 kg/ha). That is, the fitted model may not capture accurately year to year variabilities in predicted maize yield. In this analysis, predictions were limited to field samples (~600 fields) across the country of Mali. It would be valuable in the future to predict maize yield for each pixel of the new developed crop type map. That will lead to a detailed spatial analysis of maize yield, allowing identification of low yielding regions for targeted interventions which could improve food security. Keywords: Agricultural identification of croplands as crop growth condition metrics are extracted. WASC30 allowed us to derive detailed statistics on cultivated areas in the Sahel, at country and agroclimatic scales. Intensive agricultural zones were highlighted as well. The second dataset, mapping crop types for the country of Mali, is meant to separate signals of different crop types for improved crop yield estimation. The crop type map was used to derive detailed agricultural statistics (e.g. acreage by crop types, spatial distribution) at finer administrative scales than has previously been possible. The crop fraction information by crop type extracted from the map, gives additional details on farmers preferences by regions, and the natural adaptability of different crop types. The final analysis of this dissertation explores the use of ensemble machine learning techniques to predict maize yield in Mali (Chapter 5). Climate data (precipitation and temperature), and vegetation indices (Normalized Difference Vegetation Index, NDVI, the Enhanced Vegetation Index, EVI, and the Normalized Difference Water Index, NDWI) are used as predictors, while actual yields collected in 2017 by the Malian Ministry of Agriculture are the reference data. Random forest presented better predictive performance as compared to boosted regression trees (BRT). Results showed that climate variables have more predictive power for maize yield compared to vegetation indices. Among vegetation indices, the NDWI appeared to be the most influential predictor, maybe because of water requirement of maize and the sensitivity of this index to water in semi-arid regions. Tested with two different independent datasets, one constituted by 20% of the reference information, and another including observed yields for year 2018 (a one-year-left analysis), maize yield predictions were promising for year 2017 (RMSE = 362 kg/ha), but showed higher error for 2018 (RMSE = 707 kg/ha). That is, the fitted model may not capture accurately year to year variabilities in predicted maize yield. In this analysis, predictions were limited to field samples (~600 fields) across the country of Mali. It would be valuable in the future to predict maize yield for each pixel of the new developed crop type map. That will lead to a detailed spatial analysis of maize yield, allowing identification of low yielding regions for targeted interventions which could improve food security

Women in Nuclear Power Programs: Case Studies from Africa

Approximately 30 countries are considering, planning, or starting nuclear power programs, and nearly 20 more countries have expressed interest in nuclear power. Most of these countries are nuclear newcomers. According to the International Atomic Energy Agency (IAEA), a nuclear power program is a major undertaking requiring careful planning, preparation, and investments in institutions and human resources because of the safety, security, and safeguards requirements associated with the use of nuclear energy. The IAEA Milestones Approach states that states should follow three phases of development to establish the necessary infrastructure for a nuclear power program. Nuclear security is one of the 19 infrastructure issues considered throughout the three phases, alongside other infrastructure issues such as human resource development and legal and regulatory development. Despite the number of countries operating or interested in developing nuclear power plants, women comprise less than a quarter of the nuclear sector workforce. New nuclear power programs require a skilled and diverse workforce to build the necessary infrastructure and sufficiently address nuclear security. The underrepresentation of women in the field affects competitiveness, effectiveness, and diversity, and new nuclear power programs represent an opportunity to advance gender equality in nuclear security. This paper analyzes existing international, regional, and national gender equality measures and describes how a country’s nuclear power program can integrate those measures. It examines experiences from two Eastern Africa nuclear newcomers: Kenya and Uganda. Finally, the paper presents recommendations and potential solutions to address gender equality in nuclear security

RESULTATS DU TRAITEMENT DU VOLVULUS DU SIGMOÏDE A N’DJAMENA, TCHAD

The sigmoid colon volvulus is a common cause of intestinal obstruction in Africa. This work aimed to describe the treatment of sigmoid volvulus in N'djamena, Chad. Materials and Methods: This was a retrospective descriptive study realized in the General Surgery Ward of the Hopital General de Référence Nationale of N'Djamena, Chad during the period from 1/1/2010 to 31/12/2014. The records of patients operated during that period were the source of the studied data collection. The study parameters were: age, gender, physical findings and functional signs, para clinical examinations, the presence or not of colonic necrosis, the type of treatment, length of hospital stay, morbidity and mortality. Results: Sixty six cases were retained. The sigmoid volvulus constituted 9% of the operated intestinal obstruction during the study period. They were 64 men (96.7%) and 2 women (3.03%) or a sex ratio of 32/1. The clinical signs were: abdominal pain (91.2%), abdominal distension ( 88.6), and a cessation of stools and gas. (73.6%) Moreover, vomiting was found in 58 % and fever in 29,% of cases. The mean time to diagnosis was 37.7 hours (range 6 hours and 101h). The necrosis rate was 16.6% or 11 cases. The operative techniques were: resection - colostomy according Hartmann in 33 cases (50%); resection followed by immediate colo-colonic anastomosis in 23 cases (34.85%), and a simple untwisting in 10 cases (15.15%). Morbidity was 13.6% represented by two anastomotic leaks in the group of resection anastomosis, 4 parietal wall suppurations, and two medical complications. The average hospital stay was 11.2 days (range 5 days and 58 days). Mortality was 5.4%, and all concerned three patients over 60 years and with comorbidities. Conclusion: In the management of sigmoid volvulus, the Hartmann procedure is the safest method in our context. Ideal colectomy may be propsed in selected cases. The simple untwisting of the colon by laparotomy is not recommended, because of frequent relapses

Prise en charge : pré, per et post opératoire chez un drépanocytaire

La drépanocytose est une pathologie héréditaire caractérisée par une anomalie structurale de l'hémoglobine responsable d'un processus de polymérisation en situation de désoxygénation. Cliniquement, elle se manifeste par les épisodes anémiques aigus, des crises vaso-occlusives, des syndromes infectieux graves et des dégénérescences fonctionnelles multiples. En période périopératoire, la drépanocytose se caractérise par une morbidité et une mortalité élevées .La prise en charge préopératoire est dominée par la consultation d'anesthésie qui a pour but d'évaluer le retentissement fonctionnel de la maladie et d'assurer la préparation préopératoire du patient. Cette préparation vise à ramener la concentration de l'HbS autour de 30-40%. En phase peropératoire les modalités anesthésiques sont peu spécifiques, cependant certains impératifs doivent être respectés afin de minimiser le risque de falciformation. L'anesthésie loco-régionale sera privilégiée notamment en obstétrique où la morbidité est élevée. Dans la période post-opératoire, les complications ne sont pas rares. Il s'agit des crises vaso-occlusives, du syndrome thoracique aigu, de l'anémie et des thromboses. La prise en charge de ces complications passe par une bonne oxygénation, une hydratation adéquate , parfois la transfusion, les antalgiques et les antithrombotiques. Mots cles: drépanocytose, prise en charge, péri-opératoire Clinics in Mother and Child Health Vol. 1(1) 2004: 43-5

RESULTATS DU TRAITEMENT DU VOLVULUS DU SIGMOÏDE A N’DJAMENA, TCHAD

The sigmoid colon volvulus is a common cause of intestinal obstruction in Africa. This work aimed to describe the treatment of sigmoid volvulus in N'djamena, Chad. Materials and Methods: This was a retrospective descriptive study realized in the General Surgery Ward of the Hopital General de Référence Nationale of N'Djamena, Chad during the period from 1/1/2010 to 31/12/2014. The records of patients operated during that period were the source of the studied data collection. The study parameters were: age, gender, physical findings and functional signs, para clinical examinations, the presence or not of colonic necrosis, the type of treatment, length of hospital stay, morbidity and mortality. Results: Sixty six cases were retained. The sigmoid volvulus constituted 9% of the operated intestinal obstruction during the study period. They were 64 men (96.7%) and 2 women (3.03%) or a sex ratio of 32/1. The clinical signs were: abdominal pain (91.2%), abdominal distension ( 88.6), and a cessation of stools and gas. (73.6%) Moreover, vomiting was found in 58 % and fever in 29,% of cases. The mean time to diagnosis was 37.7 hours (range 6 hours and 101h). The necrosis rate was 16.6% or 11 cases. The operative techniques were: resection - colostomy according Hartmann in 33 cases (50%); resection followed by immediate colo-colonic anastomosis in 23 cases (34.85%), and a simple untwisting in 10 cases (15.15%). Morbidity was 13.6% represented by two anastomotic leaks in the group of resection anastomosis, 4 parietal wall suppurations, and two medical complications. The average hospital stay was 11.2 days (range 5 days and 58 days). Mortality was 5.4%, and all concerned three patients over 60 years and with comorbidities. Conclusion: In the management of sigmoid volvulus, the Hartmann procedure is the safest method in our context. Ideal colectomy may be propsed in selected cases. The simple untwisting of the colon by laparotomy is not recommended, because of frequent relapses

Accessibility of long-term family planning methods: a comparison study between output based approach (OBA) clients verses non-OBA clients in the voucher supported facilities in Kenya

Background: The study seeks to evaluate the difference in access of long-term family planning (LTFP) methods among the output based approach (OBA) and non-OBA clients within the OBA facility. Methods: The study utilises a quasi experimental design. A two tailed unpaired t-test with unequal variance is used to test for the significance variation in the mean access. The difference in difference (DiD) estimates of program effect on long term family planning methods is done to estimate the causal effect by exploiting the group level difference on two or more dimensions. The study also uses a linear regression model to evaluate the predictors of choice of long-term family planning methods. Data was analysed using SPSS version 17. Results: All the methods (Bilateral tubal ligation-BTL, Vasectomy, intrauterine contraceptive device -IUCD, Implants, and Total or combined long-term family planning methods -LTFP) showed a statistical significant difference in the mean utilization between OBA versus non-OBA clients. The difference in difference estimates reveal that the difference in access between OBA and non OBA clients can significantly be attributed to the implementation of the OBA program for intrauterine contraceptive device (p?=?0.002), Implants (p?=?0.004), and total or combined long-term family planning methods (p?=?0.001). The county of residence is a significant determinant of access to all long-term family planning methods except vasectomy and the year of registration is a significant determinant of access especially for implants and total or combined long-term family planning methods. The management level and facility type does not play a role in determining the type of long-term family planning method preferred; however, non-governmental organisations (NGOs) as management level influences the choice of all methods (Bilateral tubal ligation, intrauterine contraceptive device, Implants, and combined methods) except vasectomy. The adjusted R2 value, representing the percentage of the variance explained by various models, is larger than 18% for implants and total or combined long-term family planning. Conclusion: The study showed that the voucher services in Kenya has been effective in providing long-term family planning services and improving access of care provided to women of reproductive age. Therefore, voucher scheme can be used as a tool for bridging the gap of unmet needs of family planning in Kenya and could potentially be more effective if rolled out to other counties

Variability in mortality following caesarean delivery, appendectomy, and groin hernia repair in low-income and middle-income countries: a systematic review and analysis of published data

Background Surgical interventions occur at lower rates in resource-poor settings, and complication and death rates following surgery are probably substantial but have not been well quantifi ed. A deeper understanding of outcomes is a crucial step to ensure that high quality accompanies increased global access to surgical care. We aimed to assess surgical mortality following three common surgical procedures—caesarean delivery, appendectomy, and groin (inguinal and femoral) hernia repair—to quantify the potential risks of expanding access without simultaneously addressing issues of quality and safety. Methods We collected demographic, health, and economic data for 113 countries classifi ed as low income or lower-middle income by the World Bank in 2005. We did a systematic review of Ovid, MEDLINE, PubMed, and Scopus from Jan 1, 2000, to Jan 15, 2015, to identify studies in these countries reporting all-cause mortality following the three commonly undertaken operations. Reports from governmental and other agencies were also identifi ed and included. We modelled surgical mortality rates for countries without reported data using a two-step multiple imputation method. We fi rst used a fully conditional specifi cation (FCS) multiple imputation method to establish complete datasets for all missing variables that we considered potentially predictive of surgical mortality. We then used regression-based predictive mean matching imputation methods, specifi ed within the multiple imputation FCS method, for selected predictors for each operation using the completed dataset to predict mortality rates along with confi dence intervals for countries without reported mortality data. To account for variability in data availability, we aggregated results by subregion and estimated surgical mortality rates. Findings From an initial 1302 articles and reports identifi ed, 247 full-text articles met our inclusion criteria, and 124 provided data for surgical mortality for at least one of the three selected operations. We identifi ed 42 countries with mortality data for at least one of the three procedures. Median reported mortality was 7·9 per 1000 operations for caesarean delivery (IQR 2·8–19·9), 2·2 per 1000 operations for appendectomy (0·0–17·2), and 4·9 per 1000 operations for groin hernia (0·0–11·7). Perioperative mortality estimates by subregion ranged from 2·8 (South Asia) to 50·2 (East Asia) per 1000 caesarean deliveries, 2·4 (South Asia) to 54·0 (Central sub-Saharan Africa) per 1000 appendectomies, and 0·3 (Andean Latin America) to 25·5 (Southern sub-Saharan Africa) per 1000 hernia repairs. Interpretation All-cause postoperative mortality rates are exceedingly variable within resource-constrained environments. Eff orts to expand surgical access and provision of services must include a strong commitment to improve the safety and quality of care

A facility-based study of women' satisfaction and perceived quality of reproductive and maternal health services in the Kenya output-based approach voucher program

Background: This is a facility-based study designed to assess perceived quality of care and satisfaction of reproductive health services under the output-based approach (OBA) services in Kenya from clients’ perspective. Method: An exit interview was conducted on 254 clients in public health facilities, non-governmental organizations, faith-based organizations and private facilities in Kitui, Kilifi, Kiambu, and Kisumu counties as well as in the Korogocho and Viwandani slums in Nairobi, Kenya using a 23-item scale questionnaire on quality of reproductive health services. Descriptive analysis, exploratory factor analysis, reliability test, and subgroup analysis using linear regression were performed. Results: Clients generally had a positive view on staff conduct and healthcare delivery but were neutral on hospital physical facilities, resources, and access to healthcare services. There was a high overall level of satisfaction among the clients with quick service, good handling of complications, and clean hospital stated as some of the reasons that enhanced satisfaction. The County of residence was shown to impact the perception of quality greatly with other social demographic characteristics showing low impact. Conclusion: Majority of the women perceived the quality of OBA services to be high and were happy with the way healthcare providers were handling birth related complications. The conduct and practice of healthcare workers is an important determinant of client’s perception of quality of reproductive and maternal health services. Findings can be used by health care managers as a guide to evaluate different areas of healthcare delivery and to improve resources and physical facilities that are crucial in elevating clients’ level of satisfaction

The impact of macroeconomic variables on exchange rate uncertain

Macroeconomic convergence is critical for member states to achieve the level of harmonization required for establishing a stable and resilient monetary union. The East African Community (EAC) member states, therefore, established set targets for macroeconomic convergence, intending to eliminate exchange rate uncertainty within the bloc and reduce the costs of the monetary union. However, recent empirical studies indicate that the rate of convergence of the member states to the set macroeconomic targets has been very slow, resulting in high exchange rate uncertainty within the region. It is against this backdrop that this research was conceptualized to examine the influence of convergence in macroeconomic variables on the exchange rate uncertainty of EAC states using secondary panel data. The study made use of standard deviation and the Levin Lin Chu (LLC) test to determine convergence and unit root respectively. The panel ordinary least squares (OLS) regression findings showed that all the explanatory variables had a negatively significant effect on exchange rate uncertainty. This implies that convergence in macroeconomic variables among the member countries slows exchange rate uncertainty. Thus, policy should be made towards controlling this negative effect resulting from macroeconomic variables as East Africa bids for monetary union

Assessing Cropland Area in West Africa for Agricultural Yield Analysis

Accurate estimates of cultivated area and crop yield are critical to our understanding of agricultural production and food security, particularly for semi-arid regions like the Sahel of West Africa, where crop production is mainly rain-fed and food security is closely correlated with the inter-annual variations in rainfall. Several global and regional land cover products, based on satellite remotely-sensed data, provide estimates of the agricultural land use intensity, but the initial comparisons indicate considerable differences among them, relating to differences in the satellite data quality, classification approaches, and spatial and temporal resolutions. Here, we quantify the accuracy of available cropland products across Sahelian West Africa using an independent, high-resolution, visually interpreted sample dataset that classifies all points across West Africa using a 2-km sample grid (~500,000 points for the study area). We estimate the “quantity” and “allocation” disagreements for the cropland class of eight land cover products in five Western Sahel countries (Burkina Faso, Mali, Mauritania, Niger, and Senegal). The results confirm that coarse spatial resolution (300 m, 500 m, and 1000 m) land cover products have higher disagreements in mapping the fragmented agricultural landscape of the Western Sahel. Earlier products (e.g., GLC2000) are less accurate than recent products (e.g., ESA CCI 2013, MODIS 2013 and GlobCover 2009). We also show that two of the finer spatial resolution maps (GFSAD30, and GlobeLand30) using advanced classification approaches (random forest, decision trees, and pixel-object combined) are currently the best available products for cropland identification. However, none of the eight land cover databases examined is consistent in reaching the targeted 75% accuracy threshold in the five Sahelian countries. The majority of currently available land cover products overestimate cultivated areas by an average of 170% relative to the cropland area in the reference data