350 research outputs found
Leaving the nest: the rise of regional financial arrangements and the future of global governance
This article examines the impact of regional financial arrangements (RFAs) on the global liquidity regime. It argues that the design of RFAs could potentially alter the global regime, whether by strengthening it and making it more coherent or by decentring the International Monetary Fund (IMF) and destabilizing it. To determine possible outcomes, this analysis deploys a âmiddleâupâ approach that focuses on the institutional design of these RFAs. It first draws on the rational design of institutions framework to identify the internal characteristics of RFAs that are most relevant to their capabilities and capacities. It then applies these insights to the interactions of RFAs with the IMF, building on Aggarwal's (1998) concept of ânestedâ versus âparallelâ institutions, to create an analytical lens through which to assess the nature and sustainability of nested linkages. Through an analysis of the Chiang Mai Initiative Multilateralization (CMIM) and the Latin American Reserve Fund (FLAR), the article demonstrates the usefulness of this lens. It concludes by considering three circumstances in which fault lines created by these RFAsâ institutional design could be activated, permitting an institution to âleave the nestâ, including changing intentions of principals, creation of parallel capabilities and facilities, and failure of the global regime to address regional needs in a crisis.The authors would like to thank Veronica Artola, Masatsugu Asakawa, Ana Maria Carrasquilla, Junhong Chang, Paolo Hernando, Hoe Ee Khor, Kazunori Koike, Jae Young Lee, Ser-Jin Lee, Guillermo Perry, Yoichi Nemoto, Freddy Trujillo, Masaaki Watanabe, Yasuto Watanabe, Akihiko Yoshida, and others who wished to remain anonymous, for their generosity in providing in-person interviews. Further, the authors would like to thank various central bank and ministry of finance officials of both FLAR and CMIM member countries. We also thank Jose Antonio Ocampo, Diana Barrowclough, and participants in the 'Beyond Bretton Woods' Workshop at Boston University (where an earlier version of this article was presented in September 2017) for their feedback on our broader research projects on RFAs. Last but not least, the authors wish to thank the anonymous referees for their constructive comments. This work builds upon previous work funded by UNCTAD and the Global Economic Governance Initiative at the Global Development Policy Center at Boston University. (UNCTAD; Global Economic Governance Initiative at the Global Development Policy Center at Boston University)Accepted manuscrip
Optimal Power Flow in Direct Current Networks Using the Antlion Optimizer
This document presents a solution method for optimal power flow (OPF) problem in direct current (DC) networks by implementing a master-slave optimization methodology that combines an antlion optimizer (ALO) and a power flow approach based on successive approximation (SA ). In the master stage, the ALO determines the optimal amount of power to be delivered by all the distributed generators (DGs) in order to minimize the total power losses in the distribution lines of the DC network. In slave stage, the power flow problem is solved considering constant power loads and power outputs of DGs as constants. To validate the effectiveness and robustness of the proposed model, two additional comparative methods were implemented: particle swarm optimization (PSO) and black hole optimization (BHO). Two distribution test feeders (21 and 69 nodes) were simulated under different scenarios of distributed power generation. The simulations, conducted in MATLAB 2018, show that the proposed method (ALO) presents a better balance between power loss minimization and computational time required to find the optimal solution regardless of the size of the DC network
Optimal Power Dispatch in Direct Current Networks to Reduce Energy Production Costs and CO 2 Emissions Using the Antlion Optimization Algorithm
In this study, we present a masterâslave methodology to solve the problem of optimal power dispatch in a direct current (DC) microgrid. In the master stage, the Antlion Optimization (ALO) method solves the problem of power dispatch by the Distributed Generators (DGs); in the slave stage, a numerical method based on successive approximations (SA) evaluates the load flows required by the potential solutions proposed by the ALO technique. The objective functions in this paper are the minimization of energy production costs and the reduction of CO 2 emissions produced by the diesel generators in the microgrid. To favor energy efficiency and have a lower negative impact on the environment, the DC microgrids under study here include three DGs (one diesel generator and two generators based on renewable energy sources, i.e., solar energy and wind power) and a slack bus connected to a public electrical grid. The effectiveness of the proposed ALOâSA methodology was tested in the 21- and 69-bus test systems. We used three other optimization techniques to compare methods in the master stage: particle swarm optimization, continuous genetic algorithm, and black hole optimization. Additionally, we combined SA with every method to solve the load flow problem in the slave stage. The results show that, among the methods analyzed in this study, the proposed ALOâAS methodology achieves the best performance in terms of lower energy production costs, less CO 2 emissions, and shorter computational processing times. All the simulations were performed in MATLAB. Š 2021, King Fahd University of Petroleum & Minerals.Ocampo-Toro, J. A., Garzon-Rivera, O. D., Grisales-NoreĂąa, L. F., Montoya-Giraldo, O. D., & Gil-GonzĂĄlez, W. (2021). Optimal Power Dispatch in Direct Current Networks to Reduce Energy Production Costs and CO 2 Emissions Using the Antlion Optimization Algorithm. Arabian Journal for Science and Engineering, 46(10), 9995-10006
Binary Collisions and the Slingshot Effect
We derive the equations for the gravity assist manoeuvre in the general 2D
case without the constraints of circular planetary orbits or widely different
masses as assumed by Broucke, and obtain the slingshot conditions and maximum
energy gain for arbitrary mass ratios of two colliding rigid bodies. Using the
geometric view developed in an earlier paper by the authors the possible
trajectories are computed for both attractive or repulsive interactions
yielding a further insight on the slingshot mechanics and its parametrization.
The general slingshot manoeuvre for arbitrary masses is explained as a
particular case of the possible outcomes of attractive or repulsive binary
collisions, and the correlation between asymptotic information and orbital
parameters is obtained in general.Comment: 12 pages, 7 figures, accepted for publication Dec'07, Celestial
Mechanics and Dynamical Astronom
6. Peces amazĂłnicos y cambio climĂĄtico
Con el 15% de todos los peces de agua dulce descritos en el mundo, la cuenca amazĂłnica es el sistema de agua dulce mĂĄs biodiverso del planeta. Hoy en dĂa, los factores principales de degradaciĂłn de los ecosistemas de agua dulce en la regiĂłn amazĂłnica son la rĂĄpida expansiĂłn de las infraestructuras y actividades econĂłmicas. Estas perturbaciones provocan importantes efectos negativos en las comunidades de peces y podrĂan verse amplificados por los impactos del cambio climĂĄtico. Las pĂŠrdidas de hĂĄbitat originados por el cambio climĂĄtico no deberĂan tener efectos sobre las tasas de extinciĂłn de la especies. Sin embargo, el estrĂŠs tĂŠrmico y la limitaciĂłn de oxĂgeno podrĂan provocar extinciones locales de ciertas especies y producir cambios progresivos en la estructura y composiciĂłn de las comunidades actuales de peces. Las especies tolerantes al aumento de temperatura, como el Paiche, se expandirĂĄn mientras que las especies sensibles a este aumento se reducirĂĄn. Cabe destacar que hoy en dĂa las acciones de conservaciĂłn deben enfocarse en la reducciĂłn de los efectos de las amenazas antropogĂŠnicas en curso.Avec 15% de tous les poissons d'eau douce dĂŠcrits dans le monde, le bassin amazonien est le système d'eau douce prĂŠsentant la plus grande biodiversitĂŠ de la planète. Aujourd'hui, les principaux facteurs de dĂŠgradation des ĂŠcosystèmes d'eau douce dans la rĂŠgion amazonienne sont l'expansion rapide des infrastructures et les activitĂŠs ĂŠconomiques. Ces perturbations provoquent d'importants effets nĂŠgatifs sur les communautĂŠs de poissons et pourraient ĂŞtre amplifiĂŠs par les impacts du changement climatique. La perte d'habitat due au changement climatique ne devrait avoir aucun effet sur les taux d'extinction des espèces. Cependant, le stress liĂŠ Ă la tempĂŠrature et la limitation de l'oxygène pourraient provoquer l'extinction locale de certaines espèces et produire des changements progressifs dans la structure et la composition des communautĂŠs actuelles de poissons. Les populations d'espèces tolĂŠrantes Ă l'augmentation de tempĂŠrature, comme le Paiche, augmenteront, tandis que les populations d'espèces sensibles Ă cette augmentation diminueront. Il est important de noter que, Ă l'heure actuelle, les actions de conservation doivent se concentrer sur la rĂŠduction des effets des menaces anthropiques en cours.With 15% of all described freshwater fish in the world, the Amazon basin is the most biodiverse freshwater System of the planet. Nowadays, the main factors of degradation of freshwater ecosystems in the Amazon region are the rapid expansion of infrastructure and economic activities. These disturbances cause negative effects on fish communities and could be amplified by the impacts of climate change. Loss of habitat due to climate change should have no effect on rates of species extinction. However, thermal stress and oxygen limitation could cause local extinctions of certain species and produce Progressive changes in the structure and composition of existing fish communities. Tolerant species to temperature increase -as the Paiche- should expand, while sensitive species should be reduced. It is noteworthy that conservation actions should focus on reducing the effects of anthropogenic threats in progress
Assessment of Platelet REACtivity After Transcatheter Aortic Valve Replacement : The REAC-TAVI Trial
The REAC-TAVI (Assessment of platelet REACtivity after Transcatheter Aortic Valve Implantation) trial enrolled patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) pre-treated with aspirin + clopidogrel, aimed to compare the efficacy of clopidogrel and ticagrelor in suppressing high platelet reactivity (HPR) after TAVI. Current recommendations support short-term use of aspirin + clopidogrel for patients with severe AS undergoing TAVR despite the lack of compelling evidence. This was a prospective, randomized, multicenter investigation. Platelet reactivity was measured at 6 different time points with the VerifyNow assay (Accriva Diagnostics, San Diego, California). HPR was defined as (P2Y reaction units (PRU) âĽ208. Patients with HPR before TAVR were randomized to either aspirin + ticagrelor or aspirin + clopidogrel for 3 months. Patients without HPR continued with aspirin + clopidogrel (registry cohort). The primary endpoint was non-HPR status (PRU <208) in âĽ70% of patients treated with ticagrelor at 90 days post-TAVR. A total of 68 patients were included. Of these, 48 (71%) had HPR (PRU 273 Âą 09) and were randomized to aspirin + ticagrelor (n = 24, PRU 277 Âą 08) or continued with aspirin + clopidogrel (n = 24, PRU 269 Âą 49). The remaining 20 patients (29%) without HPR (PRU 133 Âą 12) were included in the registry. Overall, platelet reactivity across all the study time points after TAVR was lower in patients randomized to ticagrelor compared with those treated with clopidogrel, including those enrolled in the registry (p < 0.001). The primary endpoint was achieved in 100% of patients with ticagrelor compared with 21% with clopidogrel (p < 0.001). Interestingly, 33% of clopidogrel responder patients at baseline developed HPR status during the first month after TAVR. HPR to clopidogrel is present in a considerable number of patients with AS undergoing TAVR. Ticagrelor achieves a better and faster effect, providing sustained suppression of HPR to these patients. (Platelet Reactivity After TAVI: A Multicenter Pilot Study [REAC-TAVI]; NCT02224066
Dutch disease-cum-financialization booms and external balance cycles in developing countries
We formally investigate the medium-to-long-run dynamics emerging out of a Dutch disease-cum-financialization phenomenon. We take inspiration from the most recent Colombian development pattern. The âpureâ Dutch disease first causes deindustrialization by permanently appreciating the economyâs exchange rate in the long run. Financialization, i.e. booming capital inflows taking place in a climate of natural resource-led financial over-optimism, causes medium-run exchange rate volatility and macroeconomic instability. This jeopardizes manufacturing development even further by raising macroeconomic uncertainty. We advise the adoption of capital controls and a developmentalist monetary policy to tackle these two distinct but often intertwined phenomena
Distribution, diversity and environmental adaptation of highland papaya (Vasconcellea spp.) in tropical and subtropical America
Vasconcellea species, often referred to as highland papayas, consist of a group of fruit species that are closely related to the common papaya (Carica papaya). The genus deserves special attention as a number of species show potential as raw material in the tropical fruit industry, fresh or in processed products, or as genetic resources in papaya breeding programs. Some species show a very restricted distribution and are included in the IUCN Red List. This study on Vasconcellea distribution and diversity compiled collection data from five Vasconcellea projects and retrieved data from 62 herbaria, resulting in a total of 1,553 georeferenced collection sites, in 16 countries, including all 21 currently known Vasconcellea species. Spatial analysis of species richness clearly shows that Ecuador, Colombia and Peru are areas of high Vasconcellea diversity. Combination of species occurrence data with climatic data delimitates the potential distribution of each species and allows the modeling of potential richness at continent level. Based on these modeled richness maps, Ecuador appears to be the country with the highest potential Vasconcellea diversity. Despite differences in sampling densities, its neighboring countries, Peru and Colombia, possess high modeled species richness as well. A combination of observed richness maps and modeled potential richness maps makes it possible to identify important collection gaps. A Principal Component Analysis (PCA) of climate data at the collection sites allows us to define climatic preferences and adaptability of the different Vasconcellea species and to compare them with those of the common papaya
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
- âŚ