Sovereign-debt Renegotiations: A Strategic Analysis

The process of debt-rescheduling between a creditor and a sovereign (LDC) debtor is modeled as a noncooperative game built on a one-sector growth model. The creditor's threat to impose default penalties is ignored here as inherently incredible; instead, the debtor's motivation for repayment is to reap benefits from attaining an improved credit standing in international capital markets. The creditor can forgive portions of the outstanding debt so that a real-time bargaining process results with concessions being in the form of debt-service payments by the debtor and debt forgiveness by the creditor. Subgame-perfect equilibria of the game are characterized the main finding is that these all result in Pareto optima in which the creditor extracts all the surplus.

In the eye of the storm: gasoline markets after the hurricanes

Hurricane Katrina, 2005 ; Gasoline ; Gas industry ; Petroleum industry and trade

Gasoline content regulation as a trade barrier: do boutique fuels discourage fuel imports?

This paper examines the impact of Clean Air Act Amendments of 1990 (CAAA) environmental regulations on U.S. motor gasoline import patterns. Following the damage to U.S. petroleum refining infrastructure from hurricanes Katrina and Rita, the federal government provided temporary relief for several weeks from so-called boutique fuel specifications designed to improve air quality in certain regions of the country. These temporary waivers increased marketers’ ability to sell gasoline originally destined for specific regional markets into a greater number of markets. We hypothesize that these same waivers also encouraged gasoline imports more than increased prices would have alone. We test our hypothesis using two analyses. The first consists of a simple transfer function analysis designed to separate price effects (and thus effects of refinery closures) from the effects of regulatory relief. The second analysis consists of a natural experiment comparing the primary recipient of regulatory relief—the Gulf Coast gasoline market— to the rest of the United States. Both analyses suggest that the CAAA-related specifications prevent a substantial amount of gasoline imports from entering the United States under normal circumstances.

Role of Membrane GM1 on Early Neuronal Membrane Actions of Aβ During Onset of Alzheimer\u27s Disease

The ability of beta-amyloid peptide (Aβ) to disrupt the plasma membrane through formation of pores and membrane breakage has been previously described. However, the molecular determinants for these effects are largely unknown. In this study, we examined if the association and subsequent membrane perforation induced by Aβ was dependent on GM1levels. Pretreatment of hippocampal neurons with D-PDMP decreased GM1 and Aβ clustering at the membrane (Aβ fluorescent-punctas/20 μm, control = 16.2 ± 1.1 vs. D-PDMP = 6.4 ± 0.4, p \u3c 0.001). Interestingly, membrane perforation with Aβ occurred with a slower time course when the GM1 content was diminished (time to establish perforated configuration (TEPC) (min): control = 7.8 ± 2 vs. low GM1 = 12.1 ± 0.5, p \u3c 0.01), suggesting that the presence of GM1 in the membrane can modulate the distribution and the membrane perforation by Aβ. On the other hand, increasing GM1 facilitated the membrane perforation (TEPC: control = 7.8 ± 2 vs. GM1 = 6.2 ± 1 min, p \u3c 0.05). Additionally, using Cholera Toxin Subunit-B (CTB) to block the interaction of Aβ with GM1 attenuated membrane perforation significantly. Furthermore, pretreatment with CTB decreased the membrane association of Aβ (fluorescent-punctas/20 μm, Aβ: control = 14.8 ± 2.5 vs. CTB = 8 ± 1.4, p \u3c 0.05), suggesting that GM1 also plays a role in both association of Aβ with the membrane and in perforation. In addition, blockade of the Aβ association with CTB inhibited synaptotoxicity. Taken together, our results strongly suggest that membrane lipid composition can affect the ability of Aβ to associate and subsequently perforate the plasma membrane thereby modulating its neurotoxicity in hippocampal neurons

Human epicardial adipose tissue expresses a pathogenic profile of adipocytokines in patients with cardiovascular disease

Introduction: Inflammation contributes to cardiovascular disease and is exacerbated with increased adiposity, particularly omental adiposity; however, the role of epicardial fat is poorly understood. Methods: For these studies the expression of inflammatory markers was assessed in epicardial fat biopsies from coronary artery bypass grafting (CABG) patients using quantitative RT-PCR. Further, the effects of chronic medications, including statins, as well as peri-operative glucose, insulin and potassium infusion, on gene expression were also assessed. Circulating resistin, CRP, adiponectin and leptin levels were determined to assess inflammation. Results: The expression of adiponectin, resistin and other adipocytokine mRNAs were comparable to that in omental fat. Epicardial CD45 expression was significantly higher than control depots (p < 0.01) indicating significant infiltration of macrophages. Statin treated patients showed significantly lower epicardial expression of IL-6 mRNA, in comparison with the control abdominal depots (p < 0.001). The serum profile of CABG patients showed significantly higher levels of both CRP (control: 1.28 ± 1.57 μg/mL vs CABG: 9.11 ± 15.7 μg/mL; p < 0.001) and resistin (control: 10.53 ± 0.81 ng/mL vs CABG: 16.8 ± 1.69 ng/mL; p < 0.01) and significantly lower levels of adiponectin (control: 29.1 ± 14.8 μg/mL vs CABG: 11.9 ± 6.0 μg/mL; p < 0.05) when compared to BMI matched controls. Conclusion: Epicardial and omental fat exhibit a broadly comparable pathogenic mRNA profile, this may arise in part from macrophage infiltration into the epicardial fat. This study highlights that chronic inflammation occurs locally as well as systemically potentially contributing further to the pathogenesis of coronary artery disease

Mitigating the carbon footprint and improving productivity of ruminant livestock agriculture using a red seaweed

Ruminants are responsible for a large proportion of agricultural greenhouse gas emissions in the form of methane. This can be managed. It is a global initiative to increase productivity of the livestock sector to meet a growing population, but with emphasis on decreasing enteric methane to achieve emissions targets. We investigated the marine red macroalga (seaweed) Asparagopsis taxiformis as a feed ingredient to fundamentally eliminate enteric methane in beef cattle fed a high grain diet and provide evidence of improved livestock production performance. Asparagopsis was included in the feed of Brahman-Angus cross steers at 0.00%, 0.05%, 0.10%, and 0.20% of feed organic matter. Emissions were monitored in respiration chambers fortnightly over 90 d of treatment, steers were weighed weekly prior to feeding, feed intake monitored daily, rumen fluid samples collected in conjunction with respiration chambers for assessment of rumen function, feces were collected for bromoform residue analysis, and meat, organ, and fat were collected post slaughter for residue analysis and sensory evaluation. Steers receiving 0.10% and 0.20% Asparagopsis demonstrated decreased methane up to 40% and 98%, and demonstrated weight gain improvements of 53% and 42%, respectively. There was no negative effect on daily feed intake, feed conversion efficiencies, or rumen function, and no residues or changes in meat eating quality were detected. Commercial production of Asparagopsis could create new economies, and with low inclusion rates of this seaweed in ruminant diets the industry has the potential to revolutionize management of greenhouse gas emissions across the ruminant livestock sector with complementary benefits to the environment, and economy of the wider agriculture sector

Nature of the Neurotoxic Membrane Actions of Amyloid-β on Hippocampal Neurons in Alzheimer\u27s Disease

The mechanism by which amyloid-β (Aβ) produces brain dysfunction in patients with Alzheimer\u27s disease is largely unknown. According to previous studies, Aβ might share perforating properties with gramicidin, a well-accepted membrane-disrupting peptide. Therefore, we hypothesize that the key steps leading to synaptotoxicity by Aβ and gramicidin involve peptide aggregation, pore formation, and calcium dysregulation. Here, we show that Aβ and gramicidin form aggregates enriched in β-sheet structures using electron microscopy, and Thioflavin and Congo Red staining techniques. Also, we found that Aβ and gramicidin display fairly similar actions in hippocampal cell membranes, i.e. inducing Ca2+ entry and synaptoxicity characterized by the loss of synaptic proteins and a decrease in neuronal viability. These effects were not observed in a Ca2+ free solution, indicating that both Aβ and gramicidin induce neurotoxicity by a Ca2+-dependent mechanism. Using combined perforated patch clamp and imaging recordings, we found that only Aβ produced a perforation that progressed from a small (Cl−-selective pore) to a larger perforation that allowed the entry of fluorescent molecules. Therefore, based on these results, we propose that the perforation at the plasma membrane by Aβ is a dynamic process that is critical in producing neurotoxicity similar to that found in the brains of AD patients

Modal Frustration and Periodicity Breaking in Artificial Spin Ice

Here, an artificial spin ice lattice is introduced that exhibits unique Ising and non-Ising behavior under specific field switching protocols because of the inclusion of coupled nanomagnets into the unit cell. In the Ising regime, a magnetic switching mechanism that generates a uni- or bimodal distribution of states dependent on the alignment of the field is demonstrated with respect to the lattice unit cell. In addition, a method for generating a plethora of randomly distributed energy states across the lattice, consisting of Ising and Landau states, is investigated through magnetic force microscopy and micromagnetic modeling. It is demonstrated that the dispersed energy distribution across the lattice is a result of the intrinsic design and can be finely tuned through control of the incident angle of a critical field. The present manuscript explores a complex frustrated environment beyond the 16-vertex Ising model for the development of novel logic-based technologies

Mid-infrared Suspended Waveguide Platform and Building Blocks

In this work we present our recent progress in the development of a platform for the mid-infrared wavelength range, based on suspended silicon waveguide with subwavelength metamaterial cladding. The platform has some intrinsic advantages, which make it a very promising candidate for sensing applications in the fingerprint region. Specifically, it can cover the full transparency window of silicon (up to a wavelength of 8 μm), only requires one lithographic etch-step and can be designed for strong light-matter interaction. Design rules, practical aspects of the fabrication process and experimental results of a complete set of elemental building blocks operating at two very different wavelengths, 3.8 μm and 7.67 μm, will be discussed. Propagation losses as low as 0.82 dB/cm at λo=3.8 μm and 3.1 dB/cm at λo=7.67 μm are attained, for the interconnecting waveguides.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech