Velocity fluctuations and population distribution in clusters of settling particles at low Reynolds number

A study on the spatial organization and velocity fluctuations of non Brownian spherical particles settling at low Reynolds number in a vertical Hele-Shaw cell is reported. The particle volume fraction ranged from 0.005 to 0.05, while the distance between cell plates ranged from 5 to 15 times the particle radius. Particle tracking revealed that particles were not uniformly distributed in space but assembled in transient settling clusters. The population distribution of these clusters followed an exponential law. The measured velocity fluctuations are in agreement with that predicted theoretically for spherical clusters, from the balance between the apparent weight and the drag force. This result suggests that particle clustering, more than a spatial distribution of particles derived from random and independent events, is at the origin of the velocity fluctuations.Comment: 13 pages, 8 figure

Correlates of Hunger: Evidence from the Community Based Monitoring System (CBMS) Data of Pasay City

Hunger is one of the major problems in several countries, and the objective to reduce it has become a global concern. A major initiative of the United Nations Millenium Development Goals (MDG) is the eradication of extreme poverty and hunger. However, the attempt to reduce the abovementioned issues, calls for proper identification as to who the impoverished and hungry are. There are several ways to identify the poor, but pinpointing who the hungry are, is another task

Effects of the Vibrational Motion of XHY–ON the Post-Photo Detachment Dissociation Dynamics of the XHY Complex (X, Y = Br, I)

We explore the effects of the transition-state vibrational motions on the dynamics of the reaction X + HY →[XHY]‡→XH + Y with X and Y = Br, I. We performed simulations of the dissociation process of the unstable XHY complex using a classical trajectory methodology, combined with London-Eyring-Polanyi-Sato (LEPS) potentials to approximate the interactions among the atoms in XHY. We employed an almost classical sampling scheme on the stable XHY–species to obtain the initial conditions for the trajectories by assuming a vertical transition to the XHY neutral potential energy surface. To study the effects of the vibrations, we considered different sets of initial conditions reflecting specific XHY normal mode excitations. We found an increase in the rotational energies of the product diatoms with an increase in the energy associated to the bending normal modes of XHY. Analysis of the vibrational distributions of the diatoms shows higher most probable vibrational quantum numbers for HBr when compared to HI. For some initial conditions, we also found approximately thermal rotational distributions in the product diatoms

A scalable approach for continuous time Markov models with covariates

Existing methods for fitting continuous time Markov models (CTMM) in the presence of covariates suffer from scalability issues due to high computational cost of matrix exponentials calculated for each observation. In this article, we propose an optimization technique for CTMM which uses a stochastic gradient descent algorithm combined with differentiation of the matrix exponential using a Padé approximation. This approach makes fitting large scale data feasible. We present two methods for computing standard errors, one novel approach using the Padé expansion and the other using power series expansion of the matrix exponential. Through simulations, we find improved performance relative to existing CTMM methods, and we demonstrate the method on the large-scale multiple sclerosis NO.MS data set

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 ‘middle‐up’ 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 ‘nested’ versus ‘parallel’ 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 RFAs’ institutional design could be activated, permitting an institution to ‘leave the nest’, 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

Santo Domingo, entre la historia y la tradición hagiográfica castellana (siglos XIII-XVI)

In this paper, the current knowledge we have about the life of Santo Domingo is presented in a synthetic way, founder of the Order of Preach­ers, and the sources with which his hagiography had been constructed throughout the 13th century are analysed. From there, the additions and aspects that the 16th century chroniclers highlighted about the life of the saint are examined, educated in the ide­als of regular observance and in humanistic criticism, who, precisely, proposed the founder as the model of the observant Castilian friar. In fact, the chronicles of the Order must be considered as stories proper, but, above all, as writings of religious formation for the friars themselves.En el presente artículo, se expone en modo sintético el conocimiento actual que tene­mos sobre la vida de Santo Domingo, fundador de la Orden de Predicadores, y se analizan las fuentes con las que se había construido su hagiografía a lo largo del siglo XIII. A partir de ello, se examinan los agregados y aspectos que destacaron sobre la vida del santo los cronistas del siglo XVI, formados en los ideales de la regular observancia y en la crítica huma­nística, quienes, justamente, proponían al fundador como el modelo del fraile castellano observante. De hecho, las crónicas de la Orden deben ser considera­das como historias propiamente dichas, pero, sobre todo, como escritos de formación religiosa para los mismos frailes

Decentralized control for urban drainage systems via population dynamics: Bogotá case study

Trabajo presentado a la European Control Conference celebrada en Linz (Alemania) del 15 al 17 de julio de 2015.Control of Urban Drainage Systems (UDS) is studied for cases in which the distribution of run–off through the channels of a system is inefficient, i.e. when the capacity of some structures is not used optimally. In this paper, a decentralized population-dynamics-based control for UDS is presented, particularly using the replicator and projection dynamics. For the design, a methodology to make a partitioning of the system is introduced, and the design of a population–dynamics–based control per each partition is proposed. Moreover, a stability analysis of the closed–loop system is made by using passivity theory. Finally, simulation results show the proposed approach performance in a segment of the Bogota stormwater UDS case study.COLCIENCIAS supports J. Barreiro-Gómez and G. Obando. Agència de Gestió d’Ajust Universitaris i de Recerca AGAUR supports J. Barreiro-Gómez. This work has been partially supported by the projects “Drenaje urbano y cambio climático: Hacia los sistemas de alcantarillados del futuro. Fase II. COLCIENCIAS 633/2013”, ECOCIS (Ref. DPI2013-48243-C2-1-R), and EFFINET (Ref. FP7-ICT-2011-8-31855).Peer Reviewe