External factors in emerging market recoveries: an empirical investigation.

We estimate conditional duration models to analyse recovery processes in emerging market economies. Our reduced fonn specification is parsimonious, as we focus on the effect of growth in the US, EU, and Japan on the prospects for recovery in emerging market economies experiencing recessions. In order to assess the robustness and forecasting capability of our results, we perfonned out-of-sample predictions using recently available data pertaining to the economies hit by the Asis crisis. The model successfully predicts the bouncing back of most emerging market economies hit by the Asian crisis, and confinns the importance of external factor in recovery processes.Emerging markets; Recessions; Duration; IS-LM;

A study of non-neutral networks

Hahn and Wallsten [3] wrote that net neutrality usually means that broadband service providers charge consumers only once for Internet access, do not favor one content provider over another, and do not charge content providers for sending information over broadband lines to end users." In this paper we study the implications of being non-neutral, particularly by charging the content providers. Using game theoretic tools, we show that by adding the option for the service providers to charge the content providers, not only may the content providers and the internauts suer, but also the access provider's performance degrades

A model of network neutrality with usage-based prices

Available electronicallyby Springer since 2011International audienceHahn and Wallsten [7] wrote that network neutrality "usually means that broadband service providers charge consumers only once for Internet access, do not favor one content provider over another, and do not charge content providers for sending information over broadband lines to end users." In this paper we study the implications of non-neutral behaviors under a simple model of linear demand-response to usage-based prices. We take into account advertising revenues for the content provider and consider both cooperative and non-cooperative scenarios. In particular, we model the: impact of side-payments between service and content providers, consider an access provider that offers multiple service classes, and model leader-follower (Stackelberg game) dynamics. We finally study the additional option for one provider to determine the amount of side payment from the other provider. We show that not only do the content provider and the internaut suffer, but also the Access Provider's performance degrades

Estudos reológico e estatístico de um fluido sensível ao cisalhamento para controlar perdas de circulação

Orientador: Rosangela Barros Zanoni Lopes MorenoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de GeociênciasResumo: O pré-sal brasileiro, composto por carbonatos altamente fraturados, tem sido um enorme desafio para as operações de perfuração. Ao se perfurar carbonatos fraturados, o fluido de perfuração pode escoar para as fraturas ou cavernas, causando perda de circulação e, como consequência, controle ineficaz das pressões do fundo do poço. Este problema pode comprometer o poço e levar a um período não produtivo, custos associados a tratamentos para isolar a zona de perda e, às vezes, à perda total do poço perfurado. Existem métodos físicos e químicos ou uma combinação de ambos para o tratamento das perdas de fluido de perfuração. As soluções variam de acordo com a gravidade. Geralmente fluidos de perfuração customizados são suficientes para criar um filme denominado reboco na face do poço aberto, que previne a invasão do fluido de perfuração na rocha perfurada. Para perdas mais severas, são utilizados, lama de alta viscosidade, tampões de cimento, materiais de reticulação, gunk plug (óleo diesel-bentonita) e sistemas espessantes (também chamados de fluidos sensíveis ao cisalhamento, ou sistemas deformáveis-viscosos-coesivos). Este trabalho visa estudar um fluido capaz de selar a zona de perdas, aproveitando suas propriedades visco-elásticas e sua capacidade de permanecer como um sólido enquanto tensões são impostas. Isso está diretamente relacionado com a tensão limite de escoamento. A metodologia consiste no estudo reológico de um material composto por olefina, bentonita, surfactante (Liomul), poliacrilamida (Flopaam 6030 S) e água destilada. São realizados testes oscilatórios de cisalhamento (testes de varredura de amplitude e testes de varredura de frequência) para encontrar a tensão limite de escoamento de cada formulação. Os testes foram desenvolvidos a 25 °C, utilizando-se o reômetro Thermo Scientific HAAKE MARS III equipado com geometria de placas paralelas (P35-Ti-L, com 0,8 mm de folga). Para cada formulação, a região viscoelástica linear (LVR) foi definida e a tensão limite de escoamento foi calculada. Análises estatísticas foram aplicadas, identificando-se a melhor formulação. Os resultados para todas as formulações mostram que o módulo elástico (G¿) ultrapassa o módulo viscoso (G¿¿) para a região viscoelástica linear em 4 a 11 vezes. A partir deste estudo, pode-se concluir que o material se comporta como um sólido se submetido a tensões menores do que a tensão limite de escoamento. A tensão limite de escoamento do material é influenciada diretamente pelo teor de olefinas, e, finalmente, a formulação composta de nível baixo de olefina/bentonita (1 w%), nível baixo de agua/bentonita (2 w%), nível alto de polímero/bentonita (0,02 w%) e nível médio de tempo de agitação (90 s) é a formulação indicada para desenvolver testes de perda de circulação para avaliar as propriedades de vedação do materialAbstract: The Brazilian pre-salt is comprised of highly fractured carbonates and has been an enormous challenge for drilling operations. When carbonates are drilled, the drilling fluid can flow into the fractures or caverns, causing circulation loss and risking the well control. This problem can compromise the wellbore and leads to a non-productive time, over costs associated with treatments to isolate the thief zone, and sometimes the loss of the drilled well. There are physical and chemical methods or a combination of both for the treatments of drilling fluid loss. The solutions vary according to the severity. Generally, tailored drilling fluids are enough to create a filtered cake on the face of the open well, mitigating seepage losses. For more severe losses, high viscosity mud, cement plugs, crosslinking materials, gunk plugs (reverse diesel oil bentonite), thickening systems (also called shear-sensitive fluids or deformable-viscous-cohesive systems) are used. This work aims to study a shear-sensitive fluid, able to seal the zone of loss, taking advantage of its viscoelastic properties and its ability to stay as a solid while stress is imposed. The methodology consists of rheological and statistical studies of a material composed of olefin, bentonite, surfactant (Liomul), polyacrylamide (Flopaam 6030 S), and distilled water. Oscillatory shear tests (amplitude sweep tests and frequency sweep tests) are performed to find the yield stress of the formulations. The tests were developed at 25 °C, using the Thermo Scientific HAAKE MARS III rheometer equipped with the parallel plates geometry (P35-Ti-L, with a gap of 0.8 mm). Statistical analyses were applied, and the best formulation was identified. The results for all formulations show that the elastic modulus (G¿) surpasses the viscous modulus (G¿¿) for the linear viscoelastic region by 4 to 11 times. From the study, it can be concluded that the material behaves like a solid when submitted to stress conditions lower than the yield stress. The olefin content directly influences the final yield stress of the material. Finally, with the statistical analyses, the best formulation was defined for a low level of Olefin/Clay (1 w%), low level of Water/Clay (2 w%), high level of Polymer/Clay (0.02 w%), and a medium level of stirring time (90 s). The optimized formulation is indicated to develop future tests for lost circulation, aiming to evaluate the sealing properties of the materialMestradoReservatórios e GestãoMestre em Ciências e Engenharia de Petróleo135920-2018-35281-1700CNPQFuncam

Assessing the impact of illumination on UAV pushbroom hyperspectral imagery collected under various cloud cover conditions

The recent development of small form-factor (<6 kg), full range (400–2500 nm) pushbroom hyperspectral imaging systems (HSI) for unmanned aerial vehicles (UAV) poses a new range of opportunities for passive remote sensing applications. The flexible deployment of these UAV-HSI systems have the potential to expand the data acquisition window to acceptable (though non-ideal) atmospheric conditions. This is an important consideration for time-sensitive applications (e.g. phenology) in areas with persistent cloud cover. Since the majority of UAV studies have focused on applications with ideal illumination conditions (e.g. minimal or non-cloud cover), little is known to what extent UAV-HSI data are affected by changes in illumination conditions due to variable cloud cover. In this study, we acquired UAV pushbroom HSI (400–2500 nm) over three consecutive days with various illumination conditions (i.e. cloud cover), which were complemented with downwelling irradiance data to characterize illumination conditions and in-situ and laboratory reference panel measurements across a range of reflectivity (i.e. 2%, 10%, 18% and 50%) used to evaluate reflectance products. Using these data we address four fundamental aspects for UAV-HSI acquired under various conditions ranging from high (624.6 ± 16.63 W·m2) to low (2.5 ± 0.9 W·m2) direct irradiance: atmospheric compensation, signal-to-noise ratio (SNR), spectral vegetation indices and endmembers extraction. For instance, two atmospheric compensation methods were applied, a radiative transfer model suitable for high direct irradiance, and an Empirical Line Model (ELM) for diffuse irradiance conditions. SNR results for two distinctive vegetation classes (i.e. tree canopy vs herbaceous vegetation) reveal wavelength dependent attenuation by cloud cover, with higher SNR under high direct irradiance for canopy vegetation. Spectral vegetation index (SVIs) results revealed high variability and index dependent effects. For example, NDVI had significant differences (p < 0.05) across illumination conditions, while NDWI appeared insensitive at the canopy level. Finally, often neglected diffuse illumination conditions may be beneficial for revealing spectral features in vegetation that are obscured by the predominantly non-Lambertian reflectance encountered under high direct illumination. To our knowledge, our study is the first to use a full range pushbroom UAV sensor (400–2500 nm) for assessing illumination effects on the aforementioned variables. Our findings pave the way for understanding the advantages and limitations of ultra-high spatial resolution full range high fidelity UAV-HSI for ecological and other applications

Colloidal PbS and PbSeS Quantum Dot Sensitized Solar Cells Prepared by Electrophoretic Deposition

Here we report the developement of quantum dot sensitized solar cells (QDSCs) using colloidal PbS and PbSeS QDs and polysulfide electrolyte for high photocurrents. QDSCs have been prepared in a novel sensitizing way employing electrophoretic deposition (EPD), and protecting the colloidal QDs from corrosive electrolyte with a CdS coating. EPD allows a rapid, uniform and effective sensitization with QDs, while the CdS coating stabilizes the electrode. The effect of electrophoretic deposition time and of colloidal QD size on cell efficiency is analyzed. Efficiencies as high as 2.1±0.2% are reported

CHANG-ES XI: Circular Polarization in the Cores of Nearby Galaxies

We detect 5 galaxies in the CHANG-ES (Continuum Halos in Nearby Galaxies -- an EVLA Survey) sample that show circular polarization (CP) at L-band in our high resolution data sets. Two of the galaxies (NGC~4388 and NGC~4845) show strong Stokes $V/I\,\equiv\,m_C\,\sim\,2$\%, two (NGC~660 and NGC~3628) have values of $m_C\sim \,0.3$\%, and NGC~3079 is a marginal detection at $m_C\sim \,0.2$\%. The two strongest $m_C$ galaxies also have the most luminous X-ray cores and the strongest internal absorption in X-rays. We have expanded on our previous Faraday conversion interpretation and analysis and provide analytical expressions for the expected $V$ signal for a general case in which the cosmic ray electron energy spectral index can take on any value. We provide examples as to how such expressions could be used to estimate magnetic field strengths and the lower energy cutoff for CR electrons. Four out of our detections are {\it resolved}, showing unique structures, including a {\it jet} in NGC~4388 and a CP `conversion disk' in NGC~4845. The conversion disk is inclined to the galactic disk but is perpendicular to a possible outflow direction. Such CP structures have never before been seen in any galaxy to our knowledge. None of the galaxy cores show linear polarization at L-band. Thus CP may provide a unique probe of physical conditions deep into radio AGNs.Comment: 30 pages, 4 figures, accepted to MNRA

CHANG-ES IV: Radio continuum emission of 35 edge-on galaxies observed with the Karl G. Jansky Very Large Array in D-configuration, Data Release 1

We present the first part of the observations made for the Continuum Halos in Nearby Galaxies, an EVLA Survey (CHANG-ES) project. The aim of the CHANG-ES project is to study and characterize the nature of radio halos, their prevalence as well as their magnetic fields, and the cosmic rays illuminating these fields. This paper reports observations with the compact D configuration of the Karl G. Jansky Very Large Array (VLA) for the sample of 35 nearby edge-on galaxies of CHANG-ES. With the new wide bandwidth capabilities of the VLA, an unprecedented sensitivity was achieved for all polarization products. The beam resolution is an average of 9.6" and 36" with noise levels reaching approximately 6 and 30 microJy per beam for C- and L-bands, respectively (robust weighting). We present intensity maps in these two frequency bands (C and L), with different weightings, as well as spectral index maps, polarization maps, and new measurements of star formation rates (SFRs). The data products described herein are available to the public in the CHANG-ES data release available at www.queensu.ca/changes. We also present evidence of a trend among galaxies with larger halos having higher SFR surface density, and we show, for the first time, a radio continuum image of the median galaxy, taking advantage of the collective signal-to-noise ratio of 30 of our galaxies. This image shows clearly that a typical spiral galaxy is surrounded by a halo of magnetic fields and cosmic rays.Comment: 70 pages, of which 35 pages present the data of each galax

Development of a Roadmap for the Implementation of a Sustainable Mobility Action Plan in University Campuses of Emerging Countries

Universities are centers of knowledge and their Campuses are like small cities, thus making them the ideal place to develop, apply and evaluate policies and tools for innovative mobility solutions that can subsequently be extended to other contexts. A review of mobility measures in different European Universities has revealed that many of them apply policies to promote sustainable mobility, but there is a significant lack of standardized mobility plans and roadmaps for their successful implementation. The objective of the present work is to develop a successful roadmap, which is necessary for the smooth implementation of a mobility plan, as it has been found through a thorough review of good practices in Universities. Within this framework, a customizable standardized Roadmap design is proposed, which consists of two documents: a tactical document that provides a global and sequential vision of the entire plan, and an operational document that details the actions for each strategic line. This roadmap is accompanied by a catalog of objectives, measures, and cost and impact indicators. We consider this design instructive for universities because of its universal characteristics in Emerging Countries. To ensure this, it is necessary to apply this roadmap and carry out the corresponding evaluation

Binary black holes in Mkns as sources of gravitational radiation for space based interferometers

The possibility that some Markarian objects (e.g. Mkn 501, Mkn 421 and Mkn 766) host massive binary black hole systems with eccentric orbits at their centers has been considered. These systems could be sources of gravitational radiation for space-based gravitational wave interferometers like LISA and ASTROD. In the framework of the Lincoln -- Will approximation we simulate coalescence of such systems, calculate gravitational wave templates and discuss parameters of these binary black hole systems corresponding to the facilities of LISA and ASTROD. We discuss also the possibility to extract information about parameters of the binary black hole systems (masses, of components, distances between them, eccentricity and orbit inclination angle with respect to line of sight) from future gravitational wave measurements.Comment: in press on A&