Hasil untuk "History of Africa"

R. Beck, S. Terreblanche

Íñigo Olalde, Swapan Mallick, Swapan Mallick et al.

Genomics of the Iberian Peninsula Ancient DNA studies have begun to help us understand the genetic history and movements of people across the globe. Focusing on the Iberian Peninsula, Olalde et al. report genome-wide data from 271 ancient individuals from Iberia (see the Perspective by Vander Linden). The findings provide a comprehensive genetic time transect of the region. Linguistics analysis and genetic analysis of archaeological human remains dating from about 7000 years ago to the present elucidate the genetic impact of prehistoric and historic migrations from Europe and North Africa. Science, this issue p. 1230; see also p. 1153 Analyses of ancient human genomes document 7000 years of genetic changes in the Iberian Peninsula. We assembled genome-wide data from 271 ancient Iberians, of whom 176 are from the largely unsampled period after 2000 BCE, thereby providing a high-resolution time transect of the Iberian Peninsula. We document high genetic substructure between northwestern and southeastern hunter-gatherers before the spread of farming. We reveal sporadic contacts between Iberia and North Africa by ~2500 BCE and, by ~2000 BCE, the replacement of 40% of Iberia’s ancestry and nearly 100% of its Y-chromosomes by people with Steppe ancestry. We show that, in the Iron Age, Steppe ancestry had spread not only into Indo-European–speaking regions but also into non-Indo-European–speaking ones, and we reveal that present-day Basques are best described as a typical Iron Age population without the admixture events that later affected the rest of Iberia. Additionally, we document how, beginning at least in the Roman period, the ancestry of the peninsula was transformed by gene flow from North Africa and the eastern Mediterranean.

J. Mandel, R. Dikow, C. Siniscalchi et al.

Significance Flowering plant species represent at least 95% of all vascular plants on Earth, and members of the sunflower family comprise roughly 10% of this diversity. The family is often considered taxonomically difficult primarily because it is enormous in size and cosmopolitan in distribution. Using phylogenomics, we were able to fully resolve the backbone of the sunflower family tree. We provide evidence for a late Cretaceous origin followed by explosive diversifications and dispersals during the middle Eocene—ultimately resulting in the family’s 25,000+ extant species. Our results provide a framework to interpret the spatiotemporal patterns of migration out of South America and the family’s explosive diversifications out of Africa that led to its global evolutionary and ecological success. The sunflower family, Asteraceae, comprises 10% of all flowering plant species and displays an incredible diversity of form. Asteraceae are clearly monophyletic, yet resolving phylogenetic relationships within the family has proven difficult, hindering our ability to understand its origin and diversification. Recent molecular clock dating has suggested a Cretaceous origin, but the lack of deep sampling of many genes and representative taxa from across the family has impeded the resolution of migration routes and diversifications that led to its global distribution and tremendous diversity. Here we use genomic data from 256 terminals to estimate evolutionary relationships, timing of diversification(s), and biogeographic patterns. Our study places the origin of Asteraceae at ∼83 MYA in the late Cretaceous and reveals that the family underwent a series of explosive radiations during the Eocene which were accompanied by accelerations in diversification rates. The lineages that gave rise to nearly 95% of extant species originated and began diversifying during the middle Eocene, coincident with the ensuing marked cooling during this period. Phylogenetic and biogeographic analyses support a South American origin of the family with subsequent dispersals into North America and then to Asia and Africa, later followed by multiple worldwide dispersals in many directions. The rapid mid-Eocene diversification is aligned with the biogeographic range shift to Africa where many of the modern-day tribes appear to have originated. Our robust phylogeny provides a framework for future studies aimed at understanding the role of the macroevolutionary patterns and processes that generated the enormous species diversity of Asteraceae.

Vidya Venkatesan, Aomawa L. Shields, Russell Deitrick et al.

Eccentric planets may spend a significant portion of their orbits at large distances from their host stars, where low temperatures can cause atmospheric CO2 to condense out onto the surface, similar to the polar ice caps on Mars. The radiative effects on the climates of these planets throughout their orbits would depend on the wavelength-dependent albedo of surface CO2 ice that may accumulate at or near apoastron and vary according to the spectral energy distribution of the host star. To explore these possible effects, we incorporated a CO2 ice-albedo parameterization into a one-dimensional energy balance climate model. With the inclusion of this parameterization, our simulations demonstrated that F-dwarf planets require 29% more orbit-averaged flux to thaw out of global water ice cover compared with simulations that solely use a traditional pure water ice-albedo parameterization. When no eccentricity is assumed, and host stars are varied, F-dwarf planets with higher bond albedos relative to their M-dwarf planet counterparts require 30% more orbit-averaged flux to exit a water snowball state. Additionally, the intense heat experienced at periastron aids eccentric planets in exiting a snowball state with a smaller increase in instellation compared with planets on circular orbits; this enables eccentric planets to exhibit warmer conditions along a broad range of instellation. This study emphasizes the significance of incorporating an albedo parameterization for the formation of CO2 ice into climate models to accurately assess the habitability of eccentric planets, as we show that, even at moderate eccentricities, planets with Earth-like atmospheres can reach surface temperatures cold enough for the condensation of CO2 onto their surfaces, as can planets receiving low amounts of instellation on circular orbits.

Hisashi Hayakawa

On a centennial timescale, solar activity was quantified based on records of instrumental sunspot observations. This article briefly discusses several aspects of the recent archival investigations of historical sunspot records in the 17th to 18th centuries. This article also reviews the recent updates for the active day fraction and positions of the reported sunspot groups of the Maunder Minimum to show their significance within the observational history. These archival investigations serve as base datasets for reconstructing solar activity.

Liudmila V. Ponomarenko, Elena G. Zueva

The article commemorates the 100th anniversary of the birth of Patrice Emery Lumumba, a national hero of the Democratic Republic of the Congo (DRC), one of the most prominent leaders of the African anti-colonial movement, and the first Prime Minister of an independent country. In the late 1950s and early 1960s, his homeland became an arena for confrontation between the African liberation forces and the West, which was interested in maintaining its position in the mineral-rich country in Central Africa. In modern terms, as African countries strive to assert their sovereignty and security, strengthen their presence in the global economy and politics, it is crucial for them to rely on historical experience, taking into consideration the successes and failures of the period of struggle for independence and decolonization. Using the biographical method, the article undertakes a comprehensive analysis of the development of an individual’s life strategy as a social subject in interaction with society, examining how the environment and socio-cultural circumstances affect a person’s beliefs and behavior, and the subsequent manifestations of a unique and typical character. The research is grounded in a comprehensive examination of P. Lumumba’s speeches, correspondence, and published articles. Additionally, it draws upon annual collections of Belgian and Congolese documents on the situation in the country (1959-1961), published in Brussels. P. Lumumba’s personality was shaped by a specific system of the Belgian colonial administration. P. Lumumba was a highly intelligent individual hailing from a humble peasant background. He was a talented organizer and an excellent orator. Thanks to his natural abilities, hard work and self-education, he became one of the most respected politicians of the DRC on the eve of and in the first year of its independence. P. Lumumba founded a new political party, the Congolese National Movement, which was the only party to deviate from narrow ethnic interests. The main tenets of the program can be summarized as follows: the formation of an independent, unified, integral and indivisible Congo; the organization of the public sector, which controls the mining industry, to pursue an independent course in the economic field and in foreign policy; overcoming tribalism and regionalism; creating a just society without poverty and exploitation. In foreign policy, he focused on neutrality and Pan-Africanism. The article analyzes how, during the Cold War, such a radical policy and uncompromising stance of P. Lumumba turned the West and pro-Western forces inside the Congo against him, which caused a crisis in the country that led to the assassination of the Prime Minister. The different assessments of P. Lumumba’s activities primarily stem from the varying political positions of researchers and politicians, as well as from the contradictory worldview and the lack of formality of the politician’s own program.

D. Gurdasani, T. Carstensen, S. Fatumo et al.

Genomic studies in African populations provide unique opportunities to understand disease etiology, human diversity, and population history. In the largest study of its kind, comprising genome-wide data from 6,400 individuals and whole-genome sequences from 1,978 individuals from rural Uganda, we find evidence of geographically correlated fine-scale population substructure. Historically, the ancestry of modern Ugandans was best represented by a mixture of ancient East African pastoralists. We demonstrate the value of the largest sequence panel from Africa to date as an imputation resource. Examining 34 cardiometabolic traits, we show systematic differences in trait heritability between European and African populations, probably reflecting the differential impact of genes and environment. In a multi-trait pan-African GWAS of up to 14,126 individuals, we identify novel loci associated with anthropometric, hematological, lipid, and glycemic traits. We find that several functionally important signals are driven by Africa-specific variants, highlighting the value of studying diverse populations across the region.

Linbin Wang, Rowena Ball, Hongzhang Xu

People typically consider only European mathematics as orthodox, often intentionally or unintentionally overlooking the existence of mathematics from non-European societies. Inspired by Maria Ascher's two well-known papers on sand drawings in Oceania and Africa, this paper focuses on the strong link between modern mathematics and the mathematics behind the sand drawings. Beginning with a comparison of the geography, history, and the cultural context of sand drawings in Oceania and Africa, we will examine shared geometric features of European graph theory and Indigenous sand drawings, including continuity, cyclicity, and symmetry. The paper will also delve into the origin of graph theory, exploring whether the famous European mathematician Leonhard Euler, who published his solution to the Konigsberg bridge problem in 1736, was the true inventor of graph theory. The potential for incorporating sand drawings into the school curriculum is highlighted at the end. Overall, this paper aims to make readers realise the importance of ethnomathematics studies and appreciate the intelligence of Indigenous people.

Nuno de Fragoso Vidal

Ahmed Ali Hassan, Abdullah Al-Nafeesah, Ishag Adam et al.

Objectives There is an increasing trend of pre-diabetes and diabetes mellitus (DM) among adolescents, and sub-Saharan Africa is no exception. However, few published data on pre-diabetes among adolescents in Sudan exist. We aimed to investigate the prevalence of and factors associated with pre-diabetes among adolescents in Eastern Sudan.Design A community-based cross-sectional study was conducted from August to October 2023.Settings This community-based study was conducted in Gadarif city, the capital of Gadarif state, Eastern Sudan.Participants Adolescents (within the ages of 10–19 years).Main outcome measures A questionnaire was used to collect socio-demographic information. Anthropometric and glycated haemoglobin (HbA1c) measurements were performed in accordance with standard procedures. Multivariate logistic regression analysis was performed.Results Of the 387 enrolled adolescents, 207 (53.5%) were female and 180 (46.5%) were male. The median (IQR) age was 14.0 (12.0–16.0) years. 39.5% of the participants’ fathers were employed. The median (IQR) HbA1c was 5.5% (5.2%–5.8%). One-third (32.6%) of the adolescents had pre-diabetes or DM. Of the participants, 67.4%, 30.0% and 2.6% had no DM, pre-diabetes or type 2 DM, respectively. In the univariate analysis, the father’s employment (OR=1.60, 95% CI=1.03 to 2.50) was associated with increased odds of pre-diabetes; age, sex, parents’ education, the mother’s occupation, body mass index z-score, cigarette smoking and a family history of DM were not associated with pre-diabetes. In the multivariate analysis, the father’s employment (adjusted OR=1.70, 95% CI=1.03 to 2.50) was associated with increased odds of pre-diabetes.Conclusion Pre-diabetes is a significant public health problem among adolescents in Eastern Sudan. The introduction of early screening programmes for pre-diabetes at the community level is recommended to halt the progression of pre-diabetes to DM and to deal with existing DM among adolescents.

Hans-E. Porst

Not only motivated by the fact that the publication of the GAFT first appeared 60 years ago in print we reconstruct its history and so show that it is no exaggeration to claim that it has appeared already 75 years ago!

Andrii Voshchepynets, Oleksiy Agapitov, Lynn Wilson et al.

We present the results of processing the effects of the powerful Gamma Ray Burst GRB221009A captured by the charged particle detectors (electrostatic analyzers and solid-state detectors) onboard spacecraft at different points in the heliosphere on October 9, 2022. To follow the GRB221009A propagation through the heliosphere we used the electron and proton flux measurements from solar missions Solar Orbiter and STEREO-A; Earth magnetosphere and the solar wind missions THEMIS and Wind; meteorological satellites POES15, POES19, MetOp3; and MAVEN - a NASA mission orbiting Mars. GRB221009A had a structure of four bursts: less intense Pulse 1 - the triggering impulse - was detected by gamma-ray observatories at 131659 UT (near the Earth); the most intense Pulses 2 and 3 were detected on board all the spacecraft from the list, and Pulse 4 detected in more than 500 s after Pulse 1. Due to their different scientific objectives, the spacecraft, which data was used in this study, were separated by more than 1 AU (Solar Orbiter and MAVEN). This enabled tracking GRB221009A as it was propagating across the heliosphere. STEREO-A was the first to register Pulse 2 and 3 of the GRB, almost 100 seconds before their detection by spacecraft in the vicinity of Earth. MAVEN detected GRB221009A Pulses 2, 3, and 4 at the orbit of Mars about 237 seconds after their detection near Earth. By processing the time delays observed we show that the source location of the GRB221009A was at RA 288.5 degrees, Dec 18.5 degrees (J2000) with an error cone of 2 degrees

África Periáñez, Andrew Trister, Madhav Nekkar et al.

Malaria can be prevented, diagnosed, and treated; however, every year, there are more than 200 million cases and 200.000 preventable deaths. Malaria remains a pressing public health concern in low- and middle-income countries, especially in sub-Saharan Africa. We describe how by means of mobile health applications, machine-learning-based adaptive interventions can strengthen malaria surveillance and treatment adherence, increase testing, measure provider skills and quality of care, improve public health by supporting front-line workers and patients (e.g., by capacity building and encouraging behavioral changes, like using bed nets), reduce test stockouts in pharmacies and clinics and informing public health for policy intervention.

Pasquale C. Africa, Roberto Piersanti, Francesco Regazzoni et al.

Simulating the cardiac function requires the numerical solution of multi-physics and multi-scale mathematical models. This underscores the need for streamlined, accurate, and high-performance computational tools. Despite the dedicated endeavors of various research teams, comprehensive and user-friendly software programs for cardiac simulations are still in the process of achieving full maturity within the scientific community. This work introduces lifex-ep, a publicly available software for numerical simulations of the electrophysiology activity of the cardiac muscle, under both physiological and pathological conditions. lifex-ep employs the monodomain equation to model the heart's electrical activity. It incorporates both phenomenological and second-generation ionic models. These models are discretized using the Finite Element method on tetrahedral or hexahedral meshes. Additionally, lifex-ep integrates the generation of myocardial fibers based on Laplace-Dirichlet Rule-Based Methods, previously released in Africa et al., 2023, within lifex-fiber. This paper provides a concise overview of the mathematical models and numerical methods underlying lifex-ep, along with comprehensive implementation details and instructions for users. lifex-ep features exceptional parallel speedup, scaling efficiently when using up to thousands of cores, and its implementation has been verified against an established benchmark problem for computational electrophysiology. We showcase the key features of lifex-ep through various idealized and realistic simulations. lifex-ep offers a user-friendly and flexible interface. lifex-ep provides easy access to cardiac electrophysiology simulations for a wide user community. It offers a computational tool that integrates models and accurate methods for simulating cardiac electrophysiology within a high-performance framework, while maintaining a user-friendly interface.

Kate E. Holohan

In recent years, scholars have paid increasing attention to the material, spiritual, and collecting histories of both pre-invasion and colonial New Spanish (Mexican) featherworks. Rapidly and globally disseminated through religious and family networks, these objects traveled from Mexico to Spain, and other locations, before the end of the sixteenth century. This article explores the little-known history of a devotional featherwork <i>Ecce Homo</i> sent from Portugal to southeastern Africa in 1569. Originally a gift to Sebastian I of Portugal sent from the Spanish-colonized Americas, the <i>Ecce Homo</i> later entered the collection of Catherine of Austria, Sebastian’s grandmother. Catherine presented it to the Jesuits accompanying the Portuguese evangelizing and gold-seeking mission to Mutapa, a vast kingdom that encompassed parts of present-day Zimbabwe and Mozambique. Its intended recipient was the Mutapa emperor. However, this was not a gift meant to grease the wheels of diplomacy, nor was it designated as a tool for conversion: it was, instead, meant for the Mutapa emperor “se se convertese”—if he is converted. That is, it was conceived as a gift from one Catholic monarch to another, for use in personal devotion. The perceived spiritual efficacy of these feather images —themselves recently assimilated to Catholic Iberia from polytheistic Mesomerica—thus extended well beyond the transatlantic Iberian realms.

Ghita Rahal

In the framework of the African Strategy for Fundamental and Applied Physics AFSAP, we have launched a survey to understand the need in computing of research scientists in Africa. In this paper we summarise the survey and extract possible guidelines and recommendations to improve the situation and boost scientific research in Africa.

Erika Caranti

Named after the Hindu spring festival of Holī, horī songs generally portray the frolicsome play of the day with the throwing of coloured powders by Kṛṣṇa as the main protagonist pranking Rādhā and the gopī-s in Braj. The horī analysed in the present paper shows idiosyncrasies unveiling religious, theological, and ritual significance, besides offering precious insights into a ‘living tradition’: the celebration of Holī in the city of Banaras, at the cremation ground in Maṇikarṇikā ghāṭ where śaiva devotees enact and ‘actualise’ the horī. The song depicts Śiva playing Holī in the cremation ground with his retinue of ghostly creatures that are his favourite companions along with Aghorī-s. In place of colours, Śiva tosses the ashes from funeral pyres. In his divine dance and drumming, Mahādev uses the poisonous snakes adorning him as water-guns to squirt venom instead of gulāl. The atypical choice of Śiva in one of his fearful manifestations as the subject of a horī is discussed through references to philosophical and theological interpretations and specific symbolism. The apparent contradiction of the celebration of a lively festival in the setting of the cremation ground, resolved in the divine character of Śiva, is illustrated and contextualised starting from textual analysis.

Maarten Van Steenberge, M. Vanhove, Auguste Chocha Manda et al.

The formation history of Africa's current river basins remains largely unknown. In order to date changes in landscape and climate, we studied the biogeography of the African freshwater fish with the largest natural distribution. We also validated biogeographical units.

Jeroen van Dongen

String theorists are certain that they are practicing physicists. Yet, some of their recent critics deny this. This paper argues that this conflict is really about who holds authority in making rational judgment in theoretical physics. At bottom, the conflict centers on the question: who is a proper physicist? To illustrate and understand the differing opinions about proper practice and identity, we discuss different appreciations of epistemic virtues and explanation among string theorists and their critics, and how these have been sourced in accounts of Einstein's biography. Just as Einstein is claimed by both sides, historiography offers examples of both successful and unsuccessful non-empirical science. History of science also teaches that times of conflict are often times of innovation, in which novel scholarly identities may come into being. At the same time, since the contributions of Thomas Kuhn historians have developed a critical attitude towards formal attempts and methodological recipes for epistemic demarcation and justification of scientific practice. These are now, however, being considered in the debate on non-empirical physics.

A. C. Umuhire, J. Uwamahoro, K. Sasikumar Raja et al.

Solar radio type II bursts serve as early indicators of incoming geo-effective space weather events such as coronal mass ejections (CMEs). In order to investigate the origin of high-frequency type II bursts (HF type II bursts), we have identified 51 of them (among 180 type II bursts from SWPC reports) that are observed by ground-based Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO) spectrometers and whose upper-frequency cutoff (of either fundamental or harmonic emission) lies in between 150 MHz-450 MHz during 2010-2019. We found that 60% of HF type II bursts, whose upper-frequency cutoff $\geq$ 300 MHz originate from the western longitudes. Further, our study finds a good correlation $\sim $ 0.73 between the average shock speed derived from the radio dynamic spectra and the corresponding speed from CME data. Also, we found that analyzed HF type II bursts are associated with wide and fast CMEs located near the solar disk. In addition, we have analyzed the spatio-temporal characteristics of two of these high-frequency type II bursts and compared the derived from radio observations with those derived from multi-spacecraft CME observations from SOHO/LASCO and STEREO coronagraphs.