91 research outputs found
The Demand for Military Spending in Egypt
Egypt plays a pivotal role in the security of the Middle East as the doorway to Europe and its military expenditure reflects its involvement in the machinations of such an unstable region, showing considerable variation over the last forty years. These characteristics make it a particularly interesting case study of the determinants of military spending. This paper presents such a study, estimating an econometric model of the Egyptian demand for military spending, taking into account important strategic and political factors. Both economic and strategic factors are found to play a role in determining military burden, with clear positive effects of lagged military burden, suggesting some sort of institutional inertia, plus negative output and net imports effects. The main strategic effect is the impact of Israelâs military burden, with no effect for that of the Jordanian and Syrian allies, but the results also suggest that simple arms race relationships are not an adequate representation of the relevant strategic factors.Egypt, demand for military expenditure, political determinants, strategic determinants
The landscape of molecular chaperones across human tissues reveals a layered architecture of core and variable chaperones
The sensitivity of the protein-folding environment to chaperone disruption can be highly tissue-specific. Yet, the organization of the chaperone system across physiological human tissues has received little attention. Through computational analyses of large-scale tissue transcriptomes, we unveil that the chaperone system is composed of core elements that are uniformly expressed across tissues, and variable elements that are differentially expressed to fit with tissue-specific requirements. We demonstrate via a proteomic analysis that the muscle-specific signature is functional and conserved. Core chaperones are significantly more abundant across tissues and more important for cell survival than variable chaperones. Together with variable chaperones, they form tissue-specific functional networks. Analysis of human organ development and aging brain transcriptomes reveals that these functional networks are established in development and decline with age. In this work, we expand the known functional organization of de novo versus stress-inducible eukaryotic chaperones into a layered core-variable architecture in multi-cellular organisms
The Demand for Military Spending in Egypt
Egypt plays a pivotal role in the security of the Middle East as the doorway to Europe and its military expenditure reflects its involvement in the machinations of such an unstable region, showing considerable variation over the last 40 years. These characteristics make it a particularly interesting case study of the determinants of military spending. This paper specifies and estimates an econometric model of the Egyptian demand for military spending, taking into account important strategic and political factors. Both economic and strategic factors are found to play a role in determining military burden/spending, with clear positive effects of lagged military burden, suggesting some sort of institutional inertia, plus negative output and net exports effects. The strategic effect as a result of the impact of Israel's military burden is mostly positive and significant, though its impact is reduced when the impact of important strategic events are taken into account. The military spending of Egypt's allies Jordan and Syria generally seems to have had no effect on Egypt's spending. These results are consistent over a range of econometric techniques. © 2013 © 2013 Taylor & Francis
Technological Readiness in the Middle East and North Africa â Implications for Egypt
Effects of N-Glycosylation Site Removal in Archaellins on the Assembly and Function of Archaella in Methanococcus maripaludis
In Methanococcus maripaludis S2, the swimming organelle, the archaellum, is composed of three archaellins, FlaB1S2, FlaB2S2 and FlaB3S2. All three are modified with an N-linked tetrasaccharide at multiple sites. Disruption of the N-linked glycosylation pathway is known to cause defects in archaella assembly or function. Here, we explored the potential requirement of N-glycosylation of archaellins on archaellation by investigating the effects of eliminating the 4 N-glycosylation sites in the wildtype FlaB2S2 protein in all possible combinations either by Asn to Glu (N to Q) substitution or Asn to Asp (N to D) substitutions of the N-glycosylation sequon asparagine. The ability of these mutant derivatives to complement a non-archaellated ÎflaB2S2 strain was examined by electron microscopy (for archaella assembly) and swarm plates (for analysis of swimming). Western blot results showed that all mutated FlaB2S2 proteins were expressed and of smaller apparent molecular mass compared to wildtype FlaB2S2, consistent with the loss of glycosylation sites. In the 8 single-site mutant complements, archaella were observed on the surface of Q2, D2 and D4 (numbers after N or Q refer to the 1st to 4th glycosylation site). Of the 6 double-site mutation complementations all were archaellated except D1,3. Of the 4 triple-site mutation complements, only D2,3,4 was archaellated. Elimination of all 4 N-glycosylation sites resulted in non-archaellated cells, indicating some minimum amount of archaellin glycosylation was necessary for their incorporation into stable archaella. All complementations that led to a return of archaella also resulted in motile cells with the exception of the D4 version. In addition, a series of FlaB2S2 scanning deletions each missing 10 amino acids was also generated and tested for their ability to complement the ÎflaB2S2 strain. While most variants were expressed, none of them restored archaellation, although FlaB2S2 harbouring a smaller 3-amino acid deletion was able to partially restore archaellation
Comparative study of the extracellular proteome of Sulfolobus species reveals limited secretion
Although a large number of potentially secreted proteins can be predicted on the basis of genomic distribution of signal sequence-bearing proteins, protein secretion in Archaea has barely been studied. A proteomic inventory and comparison of the growth medium proteins in three hyperthermoacidophiles, i.e., Sulfolobus solfataricus, S. acidocaldarius and S. tokodaii, indicates that only few proteins are freely secreted into the growth medium and that the majority originates from cell envelope bound forms. In S. acidocaldarius both cell-associated and secreted α-amylase activities are detected. Inactivation of the amyA gene resulted in a complete loss of activity, suggesting that the same protein is responsible for the a-amylase activity at both locations. It is concluded that protein secretion in Sulfolobus is a limited process, and it is suggested that the S-layer may act as a barrier for the free diffusion of folded proteins into the medium
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 worldâs 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 tackleâor at least do not sufficiently tackleâ
these constraints.Vergleicht man Geschwindigkeit und Umfang der wirtschaftlichen Entwicklung der verschiedenen
Weltregionen in den vergangenen zwanzig Jahren, so fÀllt insbesondere das
unterdurchschnittliche Abschneiden der arabischen LĂ€nder im Allgemeinen und der arabischen
MittlemeerlÀnder 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 EuropÀische 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 stÀrksten behindern oder möglicherweise stÀrker als andere. Dabei benutze
ich modernste ökonometrische Verfahren, um den Einfluss der verschiedenen erklÀrenden
Variablen zu quantifizieren. Die Ergebnisse stĂŒtzen die Eingangshypothese, dass insbesondere
mangelnde technologische KapazitÀten und FÀhigkeiten sowie regionalspezifische
politökonomische Strukturen die wirtschaftliche Entwicklung in den arabischen MittelmeerlÀndern
behindern
Biochemical evidence for an alternate pathway in N-linked glycoprotein biosynthesis
Asparagine-linked glycosylation is a complex protein modification conserved among all three domains of life. Herein we report the in vitro analysis of N-linked glycosylation from the methanogenic archaeon Methanococcus voltae. Using a suite of synthetic and semisynthetic substrates, we show that AglK initiates N-linked glycosylation in M. voltae through the formation of α-linked dolichyl monophosphate N-acetylglucosamine, which contrasts with the polyprenyl diphosphate intermediates that feature in both eukaryotes and bacteria. Notably, AglK has high sequence homology to dolichyl phosphate ÎČ-glucosyltransferases, including Alg5 in eukaryotes, suggesting a common evolutionary origin. The combined action of the first two enzymes, AglK and AglC, afforded an α-linked dolichyl monophosphate glycan that serves as a competent substrate for the archaeal oligosaccharyl transferase AglB. These studies provide what is to our knowledge the first biochemical evidence revealing that, despite the apparent similarity of the overall pathways, there are actually two general strategies to achieve N-linked glycoproteins across the domains of life.National Institutes of Health (U.S.) (Grant GM039334
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