The Stock of External Sovereign Debt: Can We Take the Data At ‘Face Value’?

The stock of sovereign debt is typically measured at face value. This is a misleading indicator when debts are issued with different contractual forms. In this paper we construct a new measure of the stock of external sovereign debt for 100 developing countries from 1979 to 2006 that is invariant to contractual form, and illustrate five problems with debt stocks measured at face value. First, we show that correcting for differences in the contractual form of debt paints a very different quantitative, and in some cases also qualitative, picture of the stock of developing country external sovereign debt. Second, rankings of indebtedness across countries, which were historically used to define eligibility for debt forgiveness, are sometimes inverted once we correct for differences in contractual form. Third, the empirical performance of the benchmark quantitative model of sovereign debt deteriorates by between 40 to 70 percent once model-consistent measures of debt are used. Fourth, we show how the spread of aggregation clauses in debt contracts which award creditors voting power in proportion to the contractual face value may introduce inefficiencies into the process of restructuring sovereign debts. Fifth, we show how the use of contractual face values gives issuing countries the ability to manipulate their debt stock data, and illustrate the use of these techniques in practice.

The stock of external sovereign debt: Can we take the data at 'face value'?

The stock of sovereign debt is typically measured at face value. Defined as the undiscounted sum of future principal repayments, face values are misleading when debts are issued with different contractual forms or maturities. In this paper, we construct alternative measures of the stock of external sovereign debt for 100 developing countries from 1979 through 2006 that correct for differences in contractual form and maturity. We show that our alternative measures: (1) paint a very different quantitative, and in some cases also qualitative, picture of the stock of developing country external sovereign debt; (2) often invert rankings of indebtedness across countries, which historically defined eligibility for debt forgiveness; (3) indicate that the empirical performance of the benchmark quantitative model of sovereign debt deteriorates by roughly 50% once model-consistent measures of debt are used; (4) show how the spread of aggregation clauses in debt contracts that award creditors voting power in proportion to the contractual face value may introduce inefficiencies into the process of restructuring sovereign debts; and (5) illustrate how countries have manipulated their debt issuance to meet fiscal targets written in terms of face values

Kirigami Actuators

Thin elastic sheets bend easily and, if they are patterned with cuts, can deform in sophisticated ways. Here we show that carefully tuning the location and arrangement of cuts within thin sheets enables the design of mechanical actuators that scale down to atomically-thin 2D materials. We first show that by understanding the mechanics of a single, non-propagating crack in a sheet we can generate four fundamental forms of linear actuation: roll, pitch, yaw, and lift. Our analytical model shows that these deformations are only weakly dependent on thickness, which we confirm with experiments at centimeter scale objects and molecular dynamics simulations of graphene and MoS$_{2}$ nanoscale sheets. We show how the interactions between non-propagating cracks can enable either lift or rotation, and we use a combination of experiments, theory, continuum computational analysis, and molecular dynamics simulations to provide mechanistic insights into the geometric and topological design of kirigami actuators.Comment: Soft Matter, 201

Risk for HIV acquisition among sub-Saharan African migrant travelers in Belgium and Portugal

info:eu-repo/semantics/publishedVersio

Correlates of HIV, STI and TB among sub-Saharan African migrants in Lisbon: a biobehavioral study

info:eu-repo/semantics/publishedVersio

Draft Genome Sequence of a Pathogenic O86:H25 Sequence Type 57 Escherichia coli Strain Isolated from Poultry and Carrying 12 Acquired Antibiotic Resistance Genes

Free PMC Article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4582591/Escherichia coli is a commensal bacterium that is frequently associated with multidrug-resistant zoonotic and foodborne infections. Here, we report the 5.6-Mbp draft genome sequence of an E. coli recovered from poultry, which encodes multiple acquired antibiotic resistance determinants, virulence factors, pathogenicity determinants, and mobile genetic elements.Daniela Jones-Dias and Vera Manageiro have received research funding from Fundação para Ciência e Tecnologia (grant numbers SFRH/BD/ 80001/2011 and SFRH/BPD/77486/2011, respectively). This work was supported by Fundação para a Ciência e a Tecnologia (grant number PEst-OE/AGR/UI0211/2011-2014)

Alternative splicing is frequent during early embryonic development in mouse

<p>Abstract</p> <p>Background</p> <p>Alternative splicing is known to increase the complexity of mammalian transcriptomes since nearly all mammalian genes express multiple pre-mRNA isoforms. However, our knowledge of the extent and function of alternative splicing in early embryonic development is based mainly on a few isolated examples. High throughput technologies now allow us to study genome-wide alternative splicing during mouse development.</p> <p>Results</p> <p>A genome-wide analysis of alternative isoform expression in embryonic day 8.5, 9.5 and 11.5 mouse embryos and placenta was carried out using a splicing-sensitive exon microarray. We show that alternative splicing and isoform expression is frequent across developmental stages and tissues, and is comparable in frequency to the variation in whole-transcript expression. The genes that are alternatively spliced across our samples are disproportionately involved in important developmental processes. Finally, we find that a number of RNA binding proteins, including putative splicing factors, are differentially expressed and spliced across our samples suggesting that such proteins may be involved in regulating tissue and temporal variation in isoform expression. Using an example of a well characterized splicing factor, <it>Fox2</it>, we demonstrate that changes in <it>Fox2 </it>expression levels can be used to predict changes in inclusion levels of alternative exons that are flanked by Fox2 binding sites.</p> <p>Conclusions</p> <p>We propose that alternative splicing is an important developmental regulatory mechanism. We further propose that gene expression should routinely be monitored at both the whole transcript and the isoform level in developmental studies</p

Effects of Isometric Handgrip Training in Patients With Peripheral Artery Disease: A Randomized Controlled Trial

BackgroundMeta‐analyses have shown that isometric handgrip training (IHT) can reduce brachial systolic and diastolic blood pressure (BP) by >6/4 mm Hg, respectively. However, whether IHT promotes these effects among patients with peripheral artery disease, who exhibit severe impairment in cardiovascular function, is currently unknown. This study aimed to evaluate the effects of IHT on the cardiovascular function of patients with peripheral artery disease. Methods and ResultsA randomized controlled trial with peripheral artery disease patients assigned to either the IHT or control group was conducted. The IHT group performed 3 sessions per week, for 8 weeks, of unilateral handgrip exercises, consisting of 4 sets of isometric contractions for 2 minutes at 30% of maximum voluntary contraction and a 4‐minute interval between sets. The control group received a compression ball in order to minimize the placebo effects, representing sham training. The primary outcome was brachial BP. The secondary outcomes were central BP, arterial stiffness parameters, cardiac autonomic modulation, and vascular function. The IHT program reduced diastolic BP (75 [10] mm Hg preintervention versus 72 [11] mm Hg postintervention), with no change in the control group (74 [11] mm Hg preintervention versus 74 [11] mm Hg postintervention), with this between‐group difference being significant (P=0.04). Flow‐mediated dilation improved in the IHT group (6.0% [5.7] preintervention versus 9.7% [5.5] postintervention), with no change in the control group (7.6% [5.5] preintervention versus 7.4% [5.1] postintervention), with this between‐group difference being significant (P=0.04). There was no change in other measured variables over the intervention period. ConclusionsIHT reduced brachial diastolic BP and improved local vascular function in patients with peripheral artery disease