Simulating SST Teleconnections to Africa: What is the State of the Art?

2013 ◽  
Vol 26 (15) ◽  
pp. 5397-5418 ◽  
Author(s):  
David P. Rowell
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Coupled Model ◽  
The State ◽  
Sub Saharan Africa ◽  
Intercomparison Project ◽  
Rainfall Anomalies ◽  
Sub Saharan ◽  
Better Than

Abstract This study provides an overview of the state of the art of modeling SST teleconnections to Africa and begins to investigate the sources of error. Data are obtained from the Coupled Model Intercomparison Project (CMIP) archives, phases 3 and 5 (CMIP3 and CMIP5), using the “20C3M” and “historical” coupled model experiments. A systematic approach is adopted, with the scope narrowed to six large-scale regions of sub-Saharan Africa within which seasonal rainfall anomalies are reasonably coherent, along with six SST modes known to affect these regions. No significant nonstationarity of the strength of these 6 × 6 teleconnections is found in observations. The capability of models to represent each teleconnection is then assessed (whereby half the teleconnections have observed SST–rainfall correlations that differ significantly from zero). A few of these teleconnections are found to be relatively easy to model, while a few more pose substantial challenges to models and many others exhibit a wide variety of model skill. Furthermore, some models perform consistently better than others, with the best able to at least adequately simulate 80%–85% of the 36 teleconnections. No improvement is found between CMIP3 and CMIP5. Analysis of atmosphere-only simulations suggests that the coupled model teleconnection errors may arise primarily from errors in their SST climatology and variability, although errors in the atmospheric component of teleconnections also play a role. Last, no straightforward relationship is found between the quality of a model's teleconnection to Africa and its SST or rainfall biases or its resolution. Perhaps not surprisingly, the causes of these errors are complex, and will require considerable further investigation.

Grammaticalization in Africa

2018 ◽  
pp. 16-34 ◽  
Author(s):  
Bernd Heine
Keyword(s):  
State Of The Art ◽  
The State ◽  
Sub Saharan Africa ◽  
Theoretical Issue ◽  
African Languages ◽  
Parallel Reduction ◽  
Sub Saharan

Sub-Saharan Africa is an area for which hardly any earlier written documents are available. The student of African languages is therefore at a disadvantage when it comes to reconstructing processes of grammaticalization. That this is nevertheless possible has been demonstrated in a number of studies, using a conjunction of internal reconstruction and diachronic typological generalizations as a tool. After presenting an overview of the state of the art in grammaticalization studies in African languages, the present chapter is concerned with a more theoretical issue, namely the question of how grammaticalization processes arise. To this end, two contrasting hypotheses are discussed, namely the ‘parallel reduction’ and the ‘meaning-first’ hypotheses. Evidence from African languages suggests that it is the second hypothesis that is correct, but that both hypotheses nevertheless have their place in a framework of grammaticalization.

scholarly journals A Comparison of Feature Density for Large Scale Online Maps

2021 ◽  
Author(s):  
Michael P. Peterson
Keyword(s):  
Spatial Data ◽  
Large Scale ◽  
Sub Saharan Africa ◽  
Google Maps ◽  
Local Environments ◽  
Online Maps ◽  
Sub Saharan ◽  
Label Density ◽  
Source Of Information

Large scale maps as provided by Google, Microsoft Bing, and Mapbox among others provide users an important source of information for local environments. Comparing maps from these services helps to evaluate both the quality of the underlying spatial data and the rendering process. A comparison procedure is used that generates large scale map pairs at random locations using the Application Programmer Interface (API) for three different mapping services. The quality of each representation is then evaluated for feature and label density. The comparison is done for three different continents. For North America, it was found that maps from Google had consistently higher feature and label density than those from Microsoft Bing and Mapbox. Google Maps also held an advantage in Europe. Maps from Microsoft Bing were more detailed in Sub-Saharan Africa in comparison to both Google Maps and Mapbox. Maps from Mapbox, that relies exclusively on data from OpenStreetMap, had the lowest feature and label density for all three areas.

African election monitoring will need domestic focus

2017 ◽  
Keyword(s):  
Large Scale ◽  
Sub Saharan Africa ◽  
Quality Of Democracy ◽  
Content Type ◽  
Limited Impact ◽  
Electronic Vote ◽  
Election Monitoring ◽  
Election Observation ◽  
Sub Saharan

Subject Election monitoring in Africa Significance While electoral commissions are adopting biometric software and electronic vote transmission systems, international monitors continue to rely on manual processes. At the same time, election observation missions often fail to declare that clearly manipulated processes are "unfree and unfair". As a result, they have only a limited impact on the activities of ruling parties and electoral commissions in many countries. Impacts Allegations of election rigging are likely to mar upcoming polls in Angola, Chad and Kenya. International involvement in elections are unlikely to reverse the recent decline in the quality of democracy in sub-Saharan Africa. Investments in large-scale domestic monitoring, and the strengthening of party agents, will be necessary to reduce electoral manipulation.

scholarly journals State, Market and Citizens’ Sector in Post-Transition Societies: Towards an Inclusive Framework of Governance in Nigeria

2019 ◽  
Vol 1 (2) ◽  
pp. p211
Author(s):  
Abdulhamid Ozohu-Suleiman, Ph.D.
Keyword(s):  
Civil Society ◽  
Good Governance ◽  
Legal Framework ◽  
The State ◽  
Sub Saharan Africa ◽  
Engagement Process ◽  
State And Market ◽  
Sub Saharan ◽  
Tripartite Relationship

The crisis of governance being experienced by states in the continent of Africa since the fourth quarter of the last century has provoked widespread debates on good governance and its requirements. These debates revolve around the premises of welfarism aimed at evaluating the capacity of the state to deliver existential requirements of citizens. The point at issues is that the most significant ends of good governance are citizens and their quality of life. Thus, in connecting government with the society as a whole (to secure this mandate), scholarly preoccupation has been on the changing tripartite relationship among the state, market and the citizens’ sector. This paper seeks to interrogate this relationship in Nigeria in terms of what has been achieved and the prospects for improved quality of governance, bearing in mind the constraints imposed by certain tendencies in the democratization process. It argues that the post-transition impact of civil society (broadly referred to as citizens’ sector), which constitutes a significant part of the environment in which the state operates has not received sufficient scholarly attention in states of Sub-Saharan Africa. The paper observes that the triumph of market economy and the concomitant shrinking of the state have significantly altered the institutional landscape of governance for the citizens’ sector to deepen its engagement with a trimmed government. In other words, outside the formal institutions of the state and market, the citizens’ sector has a crucial role to play in the good governance project. In states like Nigeria, liberal political conditions have provided the needed impetus for this inclusive framework of governance to flourish. It acknowledges that though, civil society (operating under a variety of organizations) has established its visibility in the political space, none-the-less, proactive and sustainable engagement with the state on policy issues is required to effectively drive the good governance project. Be that as it may, this paper recommends among others that the legal framework in respect of this tripartite relationship should be strengthened for optimal results, and that in (specific terms), in order to deepen the collaboration between the state and the citizens’ sector, the National Assembly should make law to provide a legal framework aimed at institutionalizing the Office of the Senior Special Assistance to the Presidents on Civil Society. This institutionalization will cascade into the role of civil society in the citizen engagement process.

scholarly journals Precision Agriculture for Resource Use Efficiency in Smallholder Farming Systems in Sub-Saharan Africa: A Systematic Review

2021 ◽  
Vol 13 (3) ◽  
pp. 1158
Author(s):  
Cecilia M. Onyango ◽  
Justine M. Nyaga ◽  
Johanna Wetterlind ◽  
Mats Söderström ◽  
Kristin Piikki
Keyword(s):  
Resource Use ◽  
Precision Agriculture ◽  
Large Scale ◽  
English Language ◽  
Management Practices ◽  
Smallholder Farmers ◽  
Management Strategies ◽  
Sub Saharan Africa ◽  
Smallholder Farming ◽  
Sub Saharan

Opportunities exist for adoption of precision agriculture technologies in all parts of the world. The form of precision agriculture may vary from region to region depending on technologies available, knowledge levels and mindsets. The current review examined research articles in the English language on precision agriculture practices for increased productivity among smallholder farmers in Sub-Saharan Africa. A total of 7715 articles were retrieved and after screening 128 were reviewed. The results indicate that a number of precision agriculture technologies have been tested under SSA conditions and show promising results. The most promising precision agriculture technologies identified were the use of soil and plant sensors for nutrient and water management, as well as use of satellite imagery, GIS and crop-soil simulation models for site-specific management. These technologies have been shown to be crucial in attainment of appropriate management strategies in terms of efficiency and effectiveness of resource use in SSA. These technologies are important in supporting sustainable agricultural development. Most of these technologies are, however, at the experimental stage, with only South Africa having applied them mainly in large-scale commercial farms. It is concluded that increased precision in input and management practices among SSA smallholder farmers can significantly improve productivity even without extra use of inputs.

A new approach based on graph matching and evolutionary approach for sport scheduling problem

2020 ◽  
pp. 1-16
Author(s):  
Meriem Khelifa ◽  
Dalila Boughaci ◽  
Esma Aïmeur
Keyword(s):  
Graph Matching ◽  
State Of The Art ◽  
Travel Cost ◽  
Round Robin ◽  
New Approach ◽  
Traveling Tournament Problem ◽  
Significant Interest ◽  
National League ◽  
Better Than

The Traveling Tournament Problem (TTP) is concerned with finding a double round-robin tournament schedule that minimizes the total distances traveled by the teams. It has attracted significant interest recently since a favorable TTP schedule can result in significant savings for the league. This paper proposes an original evolutionary algorithm for TTP. We first propose a quick and effective constructive algorithm to construct a Double Round Robin Tournament (DRRT) schedule with low travel cost. We then describe an enhanced genetic algorithm with a new crossover operator to improve the travel cost of the generated schedules. A new heuristic for ordering efficiently the scheduled rounds is also proposed. The latter leads to significant enhancement in the quality of the schedules. The overall method is evaluated on publicly available standard benchmarks and compared with other techniques for TTP and UTTP (Unconstrained Traveling Tournament Problem). The computational experiment shows that the proposed approach could build very good solutions comparable to other state-of-the-art approaches or better than the current best solutions on UTTP. Further, our method provides new valuable solutions to some unsolved UTTP instances and outperforms prior methods for all US National League (NL) instances.

scholarly journals Large-scale Semantic Parsing without Question-Answer Pairs

2014 ◽  
Vol 2 ◽  
pp. 377-392 ◽  
Author(s):  
Siva Reddy ◽  
Mirella Lapata ◽  
Mark Steedman
Keyword(s):  
Natural Language ◽  
Large Scale ◽  
Graph Matching ◽  
State Of The Art ◽  
The State ◽  
Semantic Parsing ◽  
Matching Problem ◽  
Weak Supervision ◽  
Benchmark Datasets

In this paper we introduce a novel semantic parsing approach to query Freebase in natural language without requiring manual annotations or question-answer pairs. Our key insight is to represent natural language via semantic graphs whose topology shares many commonalities with Freebase. Given this representation, we conceptualize semantic parsing as a graph matching problem. Our model converts sentences to semantic graphs using CCG and subsequently grounds them to Freebase guided by denotations as a form of weak supervision. Evaluation experiments on a subset of the Free917 and WebQuestions benchmark datasets show our semantic parser improves over the state of the art.

scholarly journals Quality of care in the free maternal healthcare era in sub-Saharan Africa: a scoping review of providers’ and managers’ perceptions

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Monica Ansu-Mensah ◽  
Frederick Inkum Danquah ◽  
Vitalis Bawontuo ◽  
Peter Ansu-Mensah ◽  
Tahiru Mohammed ◽  
...  
Keyword(s):  
Quality Of Care ◽  
Research Question ◽  
Healthcare Providers ◽  
Poor Quality ◽  
Sub Saharan Africa ◽  
Healthcare Financing ◽  
Maternal Healthcare ◽  
Sub Saharan ◽  
The Impact

Abstract Background Free maternal healthcare financing schemes play an essential role in the quality of services rendered to clients during antenatal care in sub-Saharan Africa (SSA). However, healthcare managers’ and providers’ perceptions of the healthcare financing scheme may influence the quality of care. This scoping review mapped evidence on managers’ and providers’ perspectives of free maternal healthcare and the quality of care in SSA. Methods We used Askey and O’Malley’s framework as a guide to conduct this review. To address the research question, we searched PubMed, CINAHL through EBSCOhost, ScienceDirect, Web of Science, and Google Scholar with no date limitation to May 2019 using keywords, Boolean terms, and Medical Subject Heading terms to retrieve relevant articles. Both abstract and full articles screening were conducted independently by two reviewers using the inclusion and exclusion criteria as a guide. All significant data were extracted, organized into themes, and a summary of the findings reported narratively. Results In all, 15 out of 390 articles met the inclusion criteria. These 15 studies were conducted in nine countries. That is, Ghana (4), Kenya (3), and Nigeria (2), Burkina Faso (1), Burundi (1), Niger (1), Sierra Leone (1), Tanzania (1), and Uganda (1). Of the 15 included studies, 14 reported poor quality of maternal healthcare from managers’ and providers’ perspectives. Factors contributing to the perception of poor maternal healthcare included: late reimbursement of funds, heavy workload of providers, lack of essential drugs and stock-out of medical supplies, lack of policy definition, out-of-pocket payment, and inequitable distribution of staff. Conclusion This study established evidence of existing literature on the quality of care based on healthcare providers’ and managers’ perspectives though very limited. This study indicates healthcare providers and managers perceive the quality of maternal healthcare under the free financing policy as poor. Nonetheless, the free maternal care policy is very much needed towards achieving universal health, and all efforts to sustain and improve the quality of care under it must be encouraged. Therefore, more research is needed to better understand the impact of their perceived poor quality of care on maternal health outcomes.

Intraclass Correlation Coefficients for Designing Cluster-Randomized Trials in Sub-Saharan Africa Education

2016 ◽  
Vol 40 (6) ◽  
pp. 500-525 ◽  
Author(s):  
Ben Kelcey ◽  
Zuchao Shen ◽  
Jessaca Spybrook
Keyword(s):  
Large Scale ◽  
Randomized Trials ◽  
Intraclass Correlation ◽  
Educational Interventions ◽  
Sub Saharan Africa ◽  
Design Stage ◽  
Education Outcomes ◽  
Randomized Studies ◽  
Sub Saharan ◽  
Variance Explained

Objective: Over the past two decades, the lack of reliable empirical evidence concerning the effectiveness of educational interventions has motivated a new wave of research in education in sub-Saharan Africa (and across most of the world) that focuses on impact evaluation through rigorous research designs such as experiments. Often these experiments draw on the random assignment of entire clusters, such as schools, to accommodate the multilevel structure of schooling and the theory of action underlying many school-based interventions. Planning effective and efficient school randomized studies, however, requires plausible values of the intraclass correlation coefficient (ICC) and the variance explained by covariates during the design stage. The purpose of this study was to improve the planning of two-level school-randomized studies in sub-Saharan Africa by providing empirical estimates of the ICC and the variance explained by covariates for education outcomes in 15 countries. Method: Our investigation drew on large-scale representative samples of sixth-grade students in 15 countries in sub-Saharan Africa and includes over 60,000 students across 2,500 schools. We examined two core education outcomes: standardized achievement in reading and mathematics. We estimated a series of two-level hierarchical linear models with students nested within schools to inform the design of two-level school-randomized trials. Results: The analyses suggested that outcomes were substantially clustered within schools but that the magnitude of the clustering varied considerably across countries. Similarly, the results indicated that covariance adjustment generally reduced clustering but that the prognostic value of such adjustment varied across countries.

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