63 research outputs found
La distribuciĂłn de la dimensiĂłn y el tipo de propiedad de las empresas en la industria tunecina
Comment on "Performability analysis: a new algorithm"
The paper “Performability Analysis: A New Algorithm” describes an algorithm for computing the complementary distribution of the accumulated reward over an interval of time in a homogeneous Markov process. In this comment, we show that in two particular cases, one of which is quite frequent, small modifications of the algorithm may reduce significantly its storage complexity.Postprint (published version
Constraints to Economic Development and Growth in the Middle East and North Africa
When comparing the speed and extent of economic development in different geographic
regions of the world over the past 20 years, the under-average performance of Arab countries
in general and Arab Mediterranean countries in particular is striking. This is despite
an overall favorable geo-strategic situation at the crossroads of three continents, with excellent
connections to sea and waterways and in direct proximity to the European Union,
one of the world’s economic hubs. It is also despite the minor importance of negative factors
such as a high-burden diseases or high levels of ethnic fractionalization.
In this paper, I focus on identifying the most important constraints on Arab Mediterranean
economic development. I use state-of-the-art econometric tools to quantify constraints that
have been identified through economic theory and studies of the political economy characteristics
of the region. The empirical results offer support for the central hypothesis that
limited technological capacities and political economy structures are the primary constraints
on economic development. With a view to international structural adjustment efforts,
my findings imply that the limited success of the Euro-Mediterranean policy to
stimulate the economic development of the Arab Mediterranean countries might be because
structural adjustment efforts do not tackle—or at least do not sufficiently tackle—
these constraints.Vergleicht man Geschwindigkeit und Umfang der wirtschaftlichen Entwicklung der verschiedenen
Weltregionen in den vergangenen zwanzig Jahren, so fällt insbesondere das
unterdurchschnittliche Abschneiden der arabischen Länder im Allgemeinen und der arabischen
Mittlemeerländer im Besonderen ins Auge, und dies trotz einer insgesamt vorteilhaften
geographischen Lage im Schnittpunkt dreier Kontinente mit exzellenten Anschlussmöglichkeiten
an See- und Wasserwege, trotz der direkten Nachbarschaft zum
Weltwirtschaftsdrehkreuz Europäische Union und trotz der relativ geringen Bedeutung
wichtiger entwicklungshemmender Faktoren, beispielsweise ethnische Zersplitterung oder
massive Ausbreitung von Krankheiten wie AIDS oder Malaria.
In diesem Aufsatz wird versucht, von den unterschiedlichen Hemmfaktoren wirtschaftlicher
Entwicklung, die in der wirtschaftstheoretischen Literatur und/oder in MENARegionalstudien
diskutiert werden, diejenigen herauszuarbeiten, die wirtschaftliche Entwicklung
am stärksten behindern oder möglicherweise stärker als andere. Dabei benutze
ich modernste ökonometrische Verfahren, um den Einfluss der verschiedenen erklärenden
Variablen zu quantifizieren. Die Ergebnisse stĂĽtzen die Eingangshypothese, dass insbesondere
mangelnde technologische Kapazitäten und Fähigkeiten sowie regionalspezifische
politökonomische Strukturen die wirtschaftliche Entwicklung in den arabischen Mittelmeerländern
behindern
Variabilité génétique des populations tunisiennes de Myrtus communis L. (Myrtaceae) estimée par des marqueurs isoenzymatiques et moléculaires (RAPD)
The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance
INTRODUCTION
Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic.
RATIONALE
We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs).
RESULTS
Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants.
CONCLUSION
Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century
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