Hasil untuk "History of Africa"

Marco Feder, Pasquale Claudio Africa

This work presents a novel agglomeration-based multilevel preconditioner designed to accelerate the convergence of iterative solvers for linear systems arising from the discontinuous Galerkin discretization of the monodomain model in cardiac electrophysiology. The proposed approach exploits general polytopic grids at coarser levels, obtained through the agglomeration of elements from an initial, potentially fine, mesh. By leveraging a robust and efficient agglomeration strategy, we construct a nested hierarchy of grids suitable for multilevel solver frameworks. The effectiveness and performance of the methodology are assessed through a series of numerical experiments on two- and three-dimensional domains, involving different ionic models and realistic unstructured geometries. The results demonstrate strong solver effectiveness and favorable scalability with respect to both the polynomial degree of the discretization and the number of levels selected in the multigrid preconditioner.

David Demitri Africa, Suchir Salhan, Yuval Weiss et al.

Named-entity recognition (NER) in low-resource languages is usually tackled by finetuning very large multilingual LMs, an option that is often infeasible in memory- or latency-constrained settings. We ask whether small decoder LMs can be pretrained so that they adapt quickly and transfer zero-shot to languages unseen during pretraining. To this end we replace part of the autoregressive objective with first-order model-agnostic meta-learning (MAML). Tagalog and Cebuano are typologically similar yet structurally different in their actor/non-actor voice systems, and hence serve as a challenging test-bed. Across four model sizes (11 M - 570 M) MAML lifts zero-shot micro-F1 by 2-6 pp under head-only tuning and 1-3 pp after full tuning, while cutting convergence time by up to 8%. Gains are largest for single-token person entities that co-occur with Tagalog case particles si/ni, highlighting the importance of surface anchors.

David Demitri Africa, Hans Ethan Ting

Self-evaluation is increasingly central to language model training, underpinning techniques from Constitutional AI to self-refinement. We investigate whether coupling self-evaluation to reward signals creates incentives for wireheading, where agents manipulate the measurement process rather than optimizing the task. We first formalize conditions under which reward-channel control strictly dominates task-focused behavior in partially observable Markov decision processes (POMDPs). We then test these predictions empirically across two models (Llama-3.1-8B and Mistral-7B) and three tasks. We find that when self-grades determine rewards, models exhibit substantial grade inflation without corresponding accuracy gains, particularly on ambiguous tasks like summarization. While decoupling self-grades from the reward signal mitigates this inflation, models may still display lesser (but significant) overconfidence. Our results suggest that within current model scales, separating evaluation from reward removes immediate wireheading incentives. However, we caution that strictly decoupling rewards may not suffice for situationally aware models, which could learn to inflate grades for instrumental reasons (such as influencing deployment decisions) even absent direct reward coupling.

Emanuele Bottazzi, Mikhail G. Katz

We apply Nancy Cartwright's distinction between theories and basic models to explore the history of rival approaches to modeling a notion of chance for an ideal uniform physical process known as a fair spinner. This process admits both Archimedean and non-Archimedean models. Advocates of Archimedean models maintain that the fair spinner should satisfy hypotheses such as invariance with respect to rotations by an arbitrary real angle, and assume that the optimal mathematical tool in this context is the Lebesgue measure. Others argue that invariance with respect to all real rotations does not constitute an essential feature of the underlying physical process, and could be relaxed in favor of regularity. We show that, working in ZFC, no subset of the commonly assumed hypotheses determines a unique model, suggesting that physically based intuitions alone are insufficient to pin down a unique mathematical model. We provide a rebuttal of recent criticisms of non-Archimedean models by Parker and Pruss.

Mercy Nyamewaa Asiedu, Iskandar Haykel, Awa Dieng et al.

Artificial Intelligence (AI) for health has the potential to significantly change and improve healthcare. However in most African countries, identifying culturally and contextually attuned approaches for deploying these solutions is not well understood. To bridge this gap, we conduct a qualitative study to investigate the best practices, fairness indicators, and potential biases to mitigate when deploying AI for health in African countries, as well as explore opportunities where artificial intelligence could make a positive impact in health. We used a mixed methods approach combining in-depth interviews (IDIs) and surveys. We conduct 1.5-2 hour long IDIs with 50 experts in health, policy, and AI across 17 countries, and through an inductive approach we conduct a qualitative thematic analysis on expert IDI responses. We administer a blinded 30-minute survey with case studies to 672 general population participants across 5 countries in Africa and analyze responses on quantitative scales, statistically comparing responses by country, age, gender, and level of familiarity with AI. We thematically summarize open-ended responses from surveys. Our results find generally positive attitudes, high levels of trust, accompanied by moderate levels of concern among general population participants for AI usage for health in Africa. This contrasts with expert responses, where major themes revolved around trust/mistrust, ethical concerns, and systemic barriers to integration, among others. This work presents the first-of-its-kind qualitative research study of the potential of AI for health in Africa from an algorithmic fairness angle, with perspectives from both experts and the general population. We hope that this work guides policymakers and drives home the need for further research and the inclusion of general population perspectives in decision-making around AI usage.

Federico Laudisa

The Bohr and von Neumann views on the measurement process in quantum mechanics have been interpreted for a long time in somewhat controversial terms, often leading to misconceptions. On the basis of some textual analysis, I would like to show that, contrary to a widespread opinion, their views should be taken less inconsistent, and much closer to each other, than usually thought. As a consequence, I claim that Bohr and von Neumann are conceptually on the same side on the issue of the universality of quantum mechanics: hopefully, this might contribute to a more accurate history of the measurement problem in quantum mechanics.

Mohamed El Louadi

In this paper we delve into the historical evolution of data as a fundamental element in communication and knowledge transmission. The paper traces the stages of knowledge dissemination from oral traditions to the digital era, highlighting the significance of languages and cultural diversity in this progression. It also explores the impact of digital technologies on memory, communication, and cultural preservation, emphasizing the need for promoting a culture of the digital (rather than a digital culture) in Africa and beyond. Additionally, it discusses the challenges and opportunities presented by data biases in AI development, underscoring the importance of creating diverse datasets for equitable representation. We advocate for investing in data as a crucial raw material for fostering digital literacy, economic development, and, above all, cultural preservation in the digital age.

Ahmad Salman Alqahtani

En toda la literatura árabe hay abundantes ejemplos de un fenómeno que podría llamarse “analogía de la hermosura”. Generalmente, estas comparaciones constituyen alegorías en las que reiterados rasgos de una mujer ideal son equiparados con características hermosas de ciertos animales, sin que el motivo de dicha asociación quede elucidado. La notable presencia de tales analogías en la tradición árabe, tanto en la poesía como en la lexicografía, denota una extensa tópica literaria más que un mero recurso estilístico aislado. Este artículo pretende exponer e identificar dichas manifestaciones literarias, así como sugerir posibles explicaciones acerca de su razón de ser en la tradición y la cultura árabes.

Mohamad Alyousef Shirin

The research examines the concept of “Asabiyya”, its historical and semantic meaning, which goes back to the teachings of the outstanding Arab Muslim thinker Ibn Khaldun (1332-1406). Particular attention is paid to the understanding of Asabiyya as a methodological principle for analyzing the historical process, which is based on the idea of a special form of community of people. Asabiyya is the single basis for the existence of a certain mental reality on which this community is based, ensuring the maintenance and reproduction of social ties, that is, Asabiyya as a term can be considered as the personification of the high consciousness of unity, the unity of the tribal and consanguineous spirit that underlies social solidarity and group consciousness, blind adherence to this unity. Asabiyya as a theory of state formation by Ibn Khaldun's student Ibn al-Azraq (1427-1491) is seen as the main driving cyclical force of the historical process, which Ibn Khaldun first described for understanding the history of the Maghreb and North Africa. It is important to note that Ibn al-Azraq, in his political theory, considered the cyclical nature of Asabiyya as the main reason for the emergence, flourishing and decline of the state. A feature of the concept of the state of Ibn al-Azraq is that the historical cycles in it are not absolutely closed; therefore, there is the possibility of continuity between the dying and the new emerging dynasties. The founder of a new dynasty develops the customs and traditions of the previous one. In addition, the institutions of the state, in his opinion, will have to be updated and improved within the framework of continuity, provided that they still retain the basic forces for development, the most important of which is the power and authority of Asabiyya.

Ashmika Singh, Shristi Misser, Mushal Allam et al.

<i>Anopheles arabiensis</i> is a highly adaptable member of the <i>An</i>. <i>gambiae</i> complex. Its flexible resting behaviour and diverse feeding habits make conventional vector control methods less effective in controlling this species. Another emerging challenge is its adaptation to breeding in polluted water, which impacts various life history traits relevant to epidemiology. The gut microbiota of mosquitoes play a crucial role in their life history, and the larval environment significantly influences the composition of this bacterial community. Consequently, adaptation to polluted breeding sites may alter the gut microbiota of adult mosquitoes. This study aimed to examine how larval exposure to metal pollution affects the gut microbial dynamics of <i>An. arabiensis</i> adults. Larvae of <i>An. arabiensis</i> were exposed to either cadmium chloride or copper nitrate, with larvae reared in untreated water serving as a control. Two laboratory strains (SENN: insecticide unselected, SENN-DDT: insecticide selected) and F₁ larvae sourced from KwaZulu-Natal, South Africa, were exposed. The gut microbiota of the adults were sequenced using the Illumina Next Generation Sequencing platform and compared. Larval metal exposure affected alpha diversity, with a more marked difference in beta diversity. There was evidence of core microbiota shared between the untreated and metal-treated groups. Bacterial genera associated with metal tolerance were more prevalent in the metal-treated groups. Although larval metal exposure led to an increase in pesticide-degrading bacterial genera in the laboratory strains, this effect was not observed in the F₁ population. In the F₁ population, <i>Plasmodium</i>-protective bacterial genera were more abundant in the untreated group compared to the metal-treated group. This study therefore highlights the importance of considering the larval environment when searching for local bacterial symbionts for paratransgenesis interventions.

Albertino Damasceno, Amabelia Rodrigues, Nuno Lunet et al.

Introduction Pre-eclampsia is a pregnancy-related complication estimated to affect up to 8% of pregnancies worldwide. It is associated with an increased risk of postpartum sustained hypertension, coronary artery disease, cerebrovascular disease, peripheral arterial disease and cardiovascular-related mortality. Nevertheless, these associations have seldom been addressed in younger women from sub-Saharan Africa (SSA). Hence, this study aims to assess the association between pre-eclampsia and cardiovascular impairment within the first year after delivery, among younger women in SSA.Methods and analysis This is a prospective cohort study conducted at Hospital Nacional Simão Mendes in Bissau, Guinea-Bissau. A total of 230 pregnant women aged below 25 years (115 diagnosed with pre-eclampsia and 115 normotensive age-matched pregnancies), will be enrolled after their 20th gestational week. Exclusion criteria include diabetes, hypertension or other serious maternal diseases present before pregnancy. Participants will be assessed at baseline (pre-labour period), 4 and 12 months after delivery; evaluations started in March 2023 and are expected to end in December 2026. At each follow-up assessment, the women will have their blood pressure measured with a digital sphygmomanometer and a 24-hour ambulatory blood pressure monitor. Cardiac and renal function will be assessed using echocardiography and laboratory testing, respectively. Primary outcomes include the mean differences in cardiovascular and renal parameters between women who had pre-eclampsia and those who had normotensive pregnancies. Age, parity, age at first pregnancy, family history of cardiovascular diseases, smoking habits, gestational diabetes diagnosed before pre-eclampsia, body mass index and labour complications will be considered a priori as potential confounders of the association between pre-eclampsia and postpartum cardiovascular impairment.Ethics and dissemination This study was approved by the Comité Nacional de Ética em Pesquisa na Saúde, Guinea-Bissau (008/CNES/INASA/2023), and participants provide written informed consent. Results will be disseminated among the scientific community and the public.

George Boateng, Samuel John, Samuel Boateng et al.

Africa has a high student-to-teacher ratio which limits students' access to teachers for learning support such as educational question answering. In this work, we extended Kwame, a bilingual AI teaching assistant for coding education, adapted it for science education, and deployed it as a web app. Kwame for Science provides passages from well-curated knowledge sources and related past national exam questions as answers to questions from students based on the Integrated Science subject of the West African Senior Secondary Certificate Examination (WASSCE). Furthermore, students can view past national exam questions along with their answers and filter by year, question type, and topics that were automatically categorized by a topic detection model which we developed (91% unweighted average recall). We deployed Kwame for Science in the real world over 8 months and had 750 users across 32 countries (15 in Africa) and 1.5K questions asked. Our evaluation showed an 87.2% top 3 accuracy (n=109 questions) implying that Kwame for Science has a high chance of giving at least one useful answer among the 3 displayed. We categorized the reasons the model incorrectly answered questions to provide insights for future improvements. We also share challenges and lessons with the development, deployment, and human-computer interaction component of such a tool to enable other researchers to deploy similar tools. With a first-of-its-kind tool within the African context, Kwame for Science has the potential to enable the delivery of scalable, cost-effective, and quality remote education to millions of people across Africa.

Mookgo S. Kgatle, Mashilo Modiba

River baptism has biblical and historical significance in the Christian tradition. Many established mainline churches have baptismal pools where they safely conduct baptism. However, some African-Initiated Churches have been practicing river baptism because of their beliefs, theology and at times a lack of resources. While African-Initiated Churches have a theological basis for practicing river baptism, the challenge is that during rainy seasons, river baptism among African-Initiated Churches becomes hazardous because congregants can get swept away by water during the baptism ritual. This study uses an eco-theological critique to assess the relevance of river baptism amid climate change. This is a conceptual study that opted for content analysis as the research methodology. The study recommends that African-Initiated Churches that still practice river baptism must take extra caution in ensuring the safety of their congregants. If possible, life savers can be included in the baptismal programme of such churches as a way of ensuring the safety of their members. Most importantly, the African-Initiated Churches will have to rethink their theology of practicing river baptism amid climate change and other environmental crises. Such a theology should find a balance between the beliefs in river baptism and the safety of the believers. Intradisciplinary and/or interdisciplinary implications: The theological concept of baptism is discussed within the environmental science challenge of climate change. The article proposes solutions to contemporary challenges of river baptism in African-Initiated Churches through an eco-theological critique.

Olival Freire Junior

Alain Aspect's three experiments on Bell's theorem, published in the early 1980s, were a turning point in the history of the research on the foundations of quantum mechanics not only because they corroborated entanglement as the distinctive quantum signature but also because these experiments brought wider recognition to this field of research and Aspect himself. These experiments may be considered the most direct precursors of the research on quantum information, which would blossom a decade later.

Benoît Rittaud, Laurent Vivier

We reconsider the classical equality 0.999. .. = 1 with the tool of circular words, that is: finite words whose last letter is assumed to be followed by the first one. Such circular words are naturally embedded with algebraic structures that enlight this problematic equality, allowing it to be considered in Q rather than in R. We comment early history of such structures, that involves English teachers and accountants of the first part of the xviii th century, who appear to be the firsts to assert the equality 0.999. .. = 1. Their level of understanding show links with Dubinsky et al.'s apos theory in mathematics education. Eventually, we rebuilt the field Q from circular words, and provide an original proof of the fact that an algebraic integer is either an integer or an irrational number.

McLigeyo A, Owuor K, Ng'ang'a E et al.

Angela McLigeyo,1 Kevin Owuor,1 Evelyne Ng’ang’a,1 Jonathan Mwangi,2 Paul Wekesa1 1Center for Health Solutions - Kenya, Nairobi, Kenya; 2Division of Global HIV & TB, Centers for Disease Control and Prevention (CDC), Nairobi, KenyaCorrespondence: Paul Wekesa, Centre for Health Solutions – Kenya, CVS Plaza, 4th Floor, Kasuku Road, off Lenana Road, P.O. Box 23248-00100 GPO, Nairobi, Kenya, Tel +254 20 271 0077, Email pwekesa@chskenya.orgIntroduction: Kaposi’s sarcoma (KS) is the most common HIV-associated malignancy in Sub Saharan Africa. In 2018, it was the 7th most common cancer and the 10th most common cause of cancer death in Kenya. This study aimed to describe the baseline and clinical characteristics and treatment response observed following combined antiretroviral treatment (ART) and chemotherapy in KS patients.Methods: This was a descriptive analysis of patients aged ≥ 15 years treated for KS and HIV at 11 treatment hubs in Central Kenya between 2011 and 2014. Data on baseline and clinical characteristics, ART and chemotherapy regimens as well as treatment responses were collected from patient files and KS registers.Results: A total of 95 patients presenting with clinically suspected KS with no history of prior treatment with chemotherapy were reviewed. All had histological diagnostic samples taken with 67 (71%) having confirmed KS. All were on ART, either newly initiated or continuing on ART, and 63 of the 67 (94.0%) confirmed to have KS received chemotherapy. Among the 67 patients with confirmed KS, mean age was 37.2 years (± 13.2) and 40 (59.7%) were male. More than 80% had normal baseline and follow-up BMI, and 34 (50.7%) were on a TDF-based regimen, 52 (77.6%) were treated with the Adriamycin, bleomycin and vinblastine protocol, and 55 (82.1%) had KS diagnosis before HIV diagnosis. All 67 patients had mucocutaneous lesions. Complete, partial response and stable disease occurred in 27 (40.3%), 10 (14.9%) and 7 (10.4%), respectively, 11 (16.4%) defaulted care during treatment, six patients died during treatment, four patients died before treatment while two patients had progressive disease during chemotherapy.Conclusion: The diagnosis of KS preceded HIV in the majority of cases reviewed, with histology helpful to reduce misdiagnosis. Patients generally complied with their chemotherapy, with overall good response rate for this intervention implemented at primary health-care facilities.Keywords: HIV, Kaposi’s sarcoma, characteristics, treatment, response, adults

Asonzeh Ukah

Since the re-purposing of the concept of the moral economy by the British historian, E.P. Thompson in the late 1960s, scholars from a variety of disciplines in social sciences and humanities have attempted to apply it as a tool for empirical analysis. As a migratory concept, the meaning of ‘moral economy’ has shifted from theology to philosophy to anthropology and history. Scholars of religions and historians of religion, however, have shown a reluctance in deploying the concept in their field of study. A flexible and vintage concept such as the moral economy may seem to be an oxymoron when applied to the study of religion and religious reforms. Its utility, however, is demonstrated by a collection of four critical articles in this special issue of this journal to explore wide-ranging empirical materials and contexts. These include the contemporary analysis of religious morality and regulation in Northern Nigeria, the entanglements of Muslim-owned restaurants and Islam-ic morality in Mumbai (India), Zulu ethnic nationality and morality in the Nazareth Baptist Church in KwaZulu-Natal (South Africa), and finally, the pre-modern theoretical and philosophical reflections of the 14th-century Tunisian Muslim philosopher, Abd al-Rahman Ibn Khaldun. In these diverse scenarios and contexts, the moral economy concept illustrates its theoretical and analytical capacity and potential in the field of the study of religions.

Edward H. Engelbrecht, Willem A. Landman, Stephanie Landman

The interaction between the Earths surface and the atmosphere plays a key role in the initiation of cumulus convection. Over the land surface, a necessary boundary condition to consider for resolving land-atmosphere interactions is soil moisture. The aim in the study is twofold. One, through object oriented and traditional verification techniques determine how higher resolution soil moisture initial conditions influences the prediction of the location and timing of convective initiation (CI) within a convective permitting, operational NWP model over South Africa. Two, to study the modelled CI-soil moisture relationship during real afternoon thunderstorm events. The study reports the results from 66 Unified Model simulations (at 4.4km grid resolution) for nine summer afternoon CI events during synoptically benign conditions over South Africa. The higher resolution soil moisture conditions reduce centroid distance between observed and forecast storms on average by 7km (9 percent improvement), with the most decrease in centroid distance occurring at the shortest lead times, by 12km. Most improvement in location error occurs in the zonal directional. However, little to no difference is found in the timing of CI, most likely attributable to the dominant effect of model grid size on CI timing, overshadowing the influence from soil moisture anomalies. Probability of CI is highest over dry and moderate soils and areas along distinct soil moisture gradients. The conclusion is that modelled CI over South Africa preferentially occurs on the periphery of wet soil moisture patches, where there is increased surface convergence of wind and higher sensible heat flux.

Andrew Zupon, Evan Crew, Sandy Ritchie

Training data for machine learning models can come from many different sources, which can be of dubious quality. For resource-rich languages like English, there is a lot of data available, so we can afford to throw out the dubious data. For low-resource languages where there is much less data available, we can't necessarily afford to throw out the dubious data, in case we end up with a training set which is too small to train a model. In this study, we examine the effects of text normalization and data set quality for a set of low-resource languages of Africa -- Afrikaans, Amharic, Hausa, Igbo, Malagasy, Somali, Swahili, and Zulu. We describe our text normalizer which we built in the Pynini framework, a Python library for finite state transducers, and our experiments in training language models for African languages using the Natural Language Toolkit (NLTK), an open-source Python library for NLP.

Gregory Glatzer, Prasenjit Mitra, Johnson Kinyua

Understanding the movement of animals is crucial to conservation efforts. Past research often focuses on factors affecting movement, rather than locations of interest that animals return to or habitat. We explore the use of clustering to identify locations of interest to African Elephants in regions of Sub-Saharan Africa. Our analysis was performed using publicly available datasets for tracking African elephants at Kruger National Park (KNP), South Africa; Etosha National Park, Namibia; as well as areas in Burkina Faso and the Congo. Using the DBSCAN and KMeans clustering algorithms, we calculate clusters and centroids to simplify elephant movement data and highlight important locations of interest. Through a comparison of feature spaces with and without temperature, we show that temperature is an important feature to explain movement clustering. Recognizing the importance of temperature, we develop a technique to add external temperature data from an API to other geospatial datasets that would otherwise not have temperature data. After addressing the hurdles of using external data with marginally different timestamps, we consider the quality of this data, and the quality of the centroids of the clusters calculated based on this external temperature data. Finally, we overlay these centroids onto satellite imagery and locations of human settlements to validate the real-life applications of the calculated centroids to identify locations of interest for elephants. As expected, we confirmed that elephants tend to cluster their movement around sources of water as well as some human settlements, especially those with water holes. Identifying key locations of interest for elephants is beneficial in predicting the movement of elephants and preventing poaching. These methods may in the future be applied to other animals beyond elephants to identify locations of interests for them.