Gross capital flows: Dynamics and crises

This paper analyzes the behavior of international capital flows by foreign and domestic agents,dubbed gross capital flows, over the business cycle and during financial crises. We show thatgross capital flows are very large and volatile, especially relative to net capital flows. Whenforeigners invest in a country, domestic agents invest abroad, and vice versa. Gross capital flowsare also pro-cyclical. During expansions, foreigners invest more domestically and domesticagents invest more abroad. During crises, total gross flows collapse and there is a retrenchmentin both inflows by foreigners and outflows by domestic agents. These patterns hold for differenttypes of capital flows and crises. This evidence sheds light on the sources of fluctuations drivingcapital flows and helps discriminate among existing theories. Our findings seem consistent withcrises affecting domestic and foreign agents asymmetrically, as would be the case under thepresence of sovereign risk or asymmetric information.

Optical nebulosities associated with IRAS sources in dense cloud cores

I, H¿ and [SII] CCD images of the regions around 4 young IRAS sources embedded in the dense molecular cloud cores CB 6, CB 39, AFGL 5142, and L 1251 are presented. Reflection nebulosities are found in all 4 regions. Herbig-Haro objects are detected in AFGL 5142 and L 1251. In both cases, the HH objects are new discoveries.

Detection and Characterization of Preferential Flow Paths in the Downstream Area of a Hazardous Landfill

We have used surface-based electrical resistivity tomography to detect and characterize preferential hydraulic pathways in the immediate downstream area of an abandoned, hazardous landfill. The landfill occupies the void left by a former gravel pit and its base is close to the groundwater table and lacking an engineered barrier. As such, this site is remarkably typical of many small- to medium-sized waste deposits throughout the densely populated and heavily industrialized foreland on both sides of the Alpine arc. Outflows of pollutants lastingly contaminated local drinking water supplies and necessitated a partial remediation in the form of a synthetic cover barrier, which is meant to prevent meteoric water from percolating through the waste before reaching the groundwater table. Any future additional isolation of the landfill in the form of lateral barriers thus requires adequate knowledge of potential preferential hydraulic pathways for outflowing contaminants. Our results, inferred from a suite of tomographically inverted surfaced-based electrical resistivity profiles oriented roughly perpendicular to the local hydraulic gradient, indicate that potential contaminant outflows would predominantly occur along an unexploited lateral extension of the original gravel deposit. This finds its expression as a distinct and laterally continuous high-resistivity anomaly in the resistivity tomograms. This interpretation is ground-truthed through a litholog from a nearby well. Since the probed glacio-fluvial deposits are largely devoid of mineralogical clay, the geometry of hydraulic and electrical pathways across the pore space of a given lithological unit can be assumed to be identical, which allows for an order-of-magnitude estimation of the overall permeability structure. These estimates indicate that the permeability of the imaged extension of the gravel body is at least two to three orders-of-magnitude higher than that of its finer-grained embedding matrix. This corroborates the preeminent role of the high-resistivity anomaly as a potential preferential flow path.

Comparison of Compound Lean Nozzles and Controlled Flow Nozzles at Off-Design

Turbokoneet ja etenkin höyryturbiinit ovat usein suunniteltu ja optimoitu toimimaan tietyssä toimintapisteessä jossa häviöt on minimoitu ja hyötysuhde maksimoitu. Joissakin tapauksissa on kuitenkin tarpeellista käyttää turbiinia toimintapisteen ulkopuolella. Tällöin turbiinin läpi virtaava massavirta muuttuu ja yleensä heikentää hyötysuhdetta. Turbokoneiden suorituskykyä voidaan parantaa käyttämällä kolmidimensionaalisesti muotoiltuja siipiä. Työssä on vertailtu laskennallisesti kahta kohtuullisesti muotoiltua suutinta (Compound lean ja Controlled flow) niiden suunnitellun toimintapisteen ulkopuolella. Kolmas suutin, ilman kolmidimensionaalista muotoilua on mukana vertailukohteena. Suutinten suorituskykyä tutkitaan laskennallisen virtausmekaniikan avulla olosuhteissa, jotka ovat toimintapisteen ulkopuolella. Virtauksen muutoksia tutkitaan kokonaispainehäviön, isentrooppisen hyötysuhteen ja virtauspinnan yhdenmukaisuuden avulla. Virtauspintoja verrataan ulosvirtauskulman, massavirran ja toisiovirtausvektoreiden jakauman avulla. Erot suutinten suorituskykyvyssä korostavat ylikuormalla. Kun massavirran arvoa on kohotettu eniten, Compound lean suuttimilla hyötysuhde laskee Controlled flow suuttimeen verrattuna vähemmän. Alikuormalla, kun massavirran arvoa lasketaan, erot suuttimien suorituskyvyssä pienenevät ja tutkittujen suuttimien ulosvirtaus on samankaltainen.

Financial integration, capital misallocation and global imbalances

This paper shows that in a stylized model with two countries, characterized by different levels of financial development, the following facts can be replicated: 1) persistent current account surpluses and 2) high TFP growth in China. Under autarky, entrepreneurs in the emerging country overinvest in short-term projects and underinvest in long-term projects because short-term assets help them secure long-term investments in the presence of credit constraints. This creates an aggregate misallocation of capital. When financial markets integrate, entrepreneurs with long-term projects can have access to cheaper short-term assets abroad, which leaves them more resources to invest in their projects. This both reduces capital misallocations and generates capital outflows.

A Reappraisal of the Allocation Puzzle through the Portfolio Approach

Paradoxically, high-growth, high-investment developing countries tend to experience capital outflows. This paper shows that this allocation puzzle can be explained simply by introducing uninsurable idiosyncratic investment risk in the neoclassical growth model with international trade in bonds, and by taking into account not only TFP catch-up, but also the capital wedge, that is, the distortions on the return to capital. The model fits the two following facts, documented on a sample of 67 countries between 1980 and 2003: (i) TFP growth is positively correlated with capital outflows in a sample including creditor countries; (ii) the long-run level of capital per efficient unit of labor is positively correlated with capital outflows. Consistently, we show that the capital flows predicted by the model are positively correlated with the actual ones in this sample once the capital wedge is accounted for. The fact that Asia dominates global imbalances can be explained by its relatively low capital wedge.

Massive protostars as gamma-ray sources.

Massive protostars have associated bipolar outflows with velocities of hundreds of km s-1. Such outflows can produce strong shocks when they interact with the ambient medium leading to regions of nonthermal radio emission. Aims. We aim at exploring under which conditions relativistic particles are accelerated at the terminal shocks of the protostellar jets and whether they can produce significant gamma-ray emission. Methods. We estimate the conditions necessary for particle acceleration up to very high energies and gamma-ray production in the nonthermal hot spots of jets associated with massive protostars embedded in dense molecular clouds. Results. We show that relativistic bremsstrahlung and proton-proton collisions can make molecular clouds with massive young stellar objects detectable by the Fermi satellite at MeV-GeV energies and by Cherenkov telescope arrays in the GeV-TeV range. Conclusions. Gamma-ray astronomy can be used to probe the physical conditions in star-forming regions and particle acceleration processes in the complex environment of massive molecular clouds.

General Equilibrium Long-Run Determinants for Spanish FDI: A Spatial Panel Data Approach

While general equilibrium theories of trade stress the role of third-country effects, little work has been done in the empirical foreign direct investment (FDI) literature to test such spatial linkages. This paper aims to provide further insights into long-run determinants of Spanish FDI by considering not only bilateral but also spatially weighted third-country determinants. The few studies carried out so far have focused on FDI flows in a limited number of countries. However, Spanish FDI outflows have risen dramatically since 1995 and today account for a substantial part of global FDI. Therefore, we estimate recently developed Spatial Panel Data models by Maximum Likelihood (ML) procedures for Spanish outflows (1993-2004) to top-50 host countries. After controlling for unobservable effects, we find that spatial interdependence matters and provide evidence consistent with New Economic Geography (NEG) theories of agglomeration, mainly due to complex (vertical) FDI motivations. Spatial Error Models estimations also provide illuminating results regarding the transmission mechanism of shocks.

3D kinematics of the near-IR HH 223 outflow in L723

In this work, we derive the full 3D kinematics of the near-infrared outflow HH 223, located in the dark cloud Lynds 723 (L723), where a well-defined quadrupolar CO outflow is found. HH 223 appears projected on to the two lobes of the eastwest CO outflow. The radio continuum source VLA 2, towards the centre of the CO outflow, harbours a multiple system of low-mass young stellar objects. One of the components has been proposed to be the exciting source of the eastwest CO outflow. From the analysis of the kinematics, we get further evidence on the relationship between the near-infrared and CO outflows and on the location of their exciting source. The proper motions were derived using multi-epoch, narrow-band H2 (2.122 μm line) images. Radial velocities were derived from the 2.122 μm line of the spectra. Because of the extended (∼5 arcmin), S-shaped morphology of the target, the spectra were obtained with the multi-object-spectroscopy (MOS) observing mode using the instrument Long-Slit Intermediate Resolution Infrared Spectrograph (LIRIS) at the 4.2 m William Herschel Telescope. To our knowledge, this work is the first time that MOS observing mode has been successfully used in the near-infrared range for an extended target.

Non-thermal emission from microquasar/ISM interaction

Context. The interaction of microquasar jets with their environment can produce non-thermal radiation as in the case of extragalactic outflows impacting on their surroundings. Significant observational evidence of jet/medium interaction in galactic microquasars has been collected in the past few years, although little theoretical work has been done regarding the resulting non-thermal emission. Aims. In this work, we investigate the non-thermal emission produced in the interaction between microquasar jets and their environment, and the physical conditions for its production. Methods. We developed an analytical model based on those successfully applied to extragalactic sources. The jet is taken to be a supersonic and mildly relativistic hydrodynamical outflow. We focus on the jet/shocked medium structure in its adiabatic phase, and assume that it grows in a self-similar way. We calculate the fluxes and spectra of the radiation produced via synchrotron, inverse Compton, and relativistic bremsstrahlung processes by electrons accelerated in strong shocks. A hydrodynamical simulation is also performed to investigate further the jet interaction with the environment and check the physical parameters used in the analytical model. Results. For reasonable values of the magnetic field, and using typical values of the external matter density, the non-thermal particles could produce significant amounts of radiation at different wavelengths, although they do not cool primarily radiatively, but by adiabatic losses. The physical conditions of the analytical jet/medium interaction model are consistent with those found in the hydrodynamical simulation. Conclusions. Microquasar jet termination regions could be detectable at radio wavelengths for current instruments sensitive to ~arcminute scales. At X-ray energies, the expected luminosities are moderate, although the emitter is more compact than the radio one. The source may be detectable by XMM-Newton or Chandra, with 1-10 arcsec of angular resolution. The radiation at gamma-ray energies may be within the detection limits of the next generation of satellite and ground-based instruments.

Étude du système binaire CV Ser à l'aide du satellite MOST

Ce mémoire s’intéresse au système binaire massif CV Serpentis, composé d’une Wolf- Rayet riche en carbone et d’une étoile de la séquence principale, de type spectral O (WC8d + O8-9IV). D’abord, certains phénomènes affectant les étoiles massives sont mentionnés, de leur passage sur la séquence principale à leur mort (supernova). Au cours du premier cha- pitre, un rappel est fait concernant certaines bases de l’astrophysique stellaire observa- tionnelle (diagramme Hertzsprung-Russell, phases évolutives, etc...). Au chapitre suivant, un des aspects les plus importants de la vie des étoiles massives est abordé : la perte de masse sous forme de vents stellaires. Un historique de la découverte des vents ouvre le chapitre, suivi des fondements théoriques permettant d’expliquer ce phénomène. Ensuite, différents aspects propres aux vents stellaires sont présentés. Au troisième chapitre, un historique détaillé de CV Ser est présenté en guise d’introduc- tion à cet objet singulier. Ses principales caractéristiques connues y sont mentionnées. Finalement, le cœur de ce mémoire se retrouve au chapitre 4. Des courbes de lumière ultra précises du satellite MOST (2009 et 2010) montrent une variation apparente du taux de perte de masse de la WR de l’ordre de 62% sur une période orbitale de 29.701 jours. L’analyse des résidus permet de trouver une signature suggérant la présence de régions d’interaction en corotation (en anglais corotating interaction regions, ou CIR) dans le vent WR. Une nouvelle solution orbitale est présentée ainsi que les paramètres de la région de collision des vents et les types spectraux sont confirmés.

Étude observationnelle de la collision des vents dans les systèmes Wolf-Rayet+O

Nous présentons les résultats de trois campagnes d'observation d'un mois chacune dans le cadre de l'étude de la collision des vents dans les systèmes binaires Wolf-Rayet + OB. Ce travail se concentre sur l'étude des objets de l'hémisphère sud n'ayant jamais encore fait l'objet d'études poussées dans ce contexte. À cela, nous avons ajouté l'objet archétype pour ce type de systèmes : WR 140 (WC7pd + O5.5fc) qui a effectué son dernier passage périastre en janvier 2009. Les deux premières campagnes (spectroscopiques), ont permis une mise à jour des éléments orbitaux ainsi qu'une estimation de la géométrie de la zone de collision des vents et d'autres paramètres fondamentaux des étoiles pour 6 systèmes binaires : WR 12 (WN8h), 21 (WN5o+O7V), 30 (WC6+O7.5V), 31 (WN4o+O8), 47 (WN6o+O5) et 140. Une période non-orbitale courte (probablement reliée à la rotation) a également été mesurée pour un des objets : WR 69 (WC9d+OB), avec une période orbitale bien plus grande. La troisième campagne (photométrique) a révélé une variabilité étonnamment faible dans un échantillon de 20 étoiles WC8/9. Cela supporte l'idée que les pulsations ne sont pas courantes dans ce type d'étoiles et qu'il est peu probable que celles-ci soient le mécanisme dominant de formation de poussière, suggérant, par défaut, le rôle prédominant de la collision des vents.

A study of the large-scale structure of the wind of WR 134

Diverses méthodes ont été utilisées pour étudier les étoiles Wolf-Rayet (WR) dans le but de comprendre les phénomènes physiques variés qui prennent place dans leur vent dense. Pour étudier la variabilité qui n'est pas strictement périodique et ayant des caractéristiques différentes d'une époque à l'autre, il faut observer pendant des périodes de temps suffisamment longues en adopter un échantillonnage temporel élevé pour être en mesure d'identifier les phénomènes physiques sous-jacents. À l'été 2013, des astronomes professionnels et amateurs du monde entier ont contribué à une campagne d'observation de 4 mois, principalement en spectroscopie, mais aussi en photométrie, polarimétrie et en interférométrie, pour observer les 3 premières étoiles Wolf-Rayet découvertes: WR 134 (WN6b), WR 135 (WC8) et WR 137 (WC7pd + O9). Chacune de ces étoiles est intéressante à sa manière, chacune présentant une variété différente de structures dans son vent. Les données spectroscopiques de cette campagne ont été réduites et analysées pour l'étoile présumée simple WR 134 pour mieux comprendre le comportement de sa variabilité périodique à long terme dans le cadre d'une étude des régions d'interactions en corotation (CIRs) qui se retrouvent dans son vent. Les résultats de cette étude sont présentés dans ce mémoire.

Effect of management strategies on the performance of ruminant livestock production systems and the safety of plant and animal products in the city of Sikasso, Mali

The regional population growth in West Africa, and especially its urban centers, will bring about new and critical challenges for urban development policy, especially in terms of ensuring food security and providing employment for the growing population. (Peri-) urban livestock and vegetable production systems, which can contribute significantly to these endeavours, are limited by various constraints, amongst them limited access to expensive production factors and their (in)efficient use. To achieve sustainable production systems with low consumer health risks, that can meet the urban increased demand, this doctoral thesis determined nutrient use efficiencies in representative (peri-) urban livestock production systems in three West African cities, and investigated potential health risks for consumers ensuing from there. The field study, which was conducted during July 2007 to December 2009, undertook a comparative analysis of (peri-) urban livestock production strategies across 210 livestock keeping households (HH) in the three West African cities of Kano/Nigeria (84 HH), Bobo Dioulasso/Burkina Faso (63 HH) and Sikasso/Mali (63 HH). These livestock enterprises were belonging to the following three farm types: commercial gardening plus field crops and livestock (cGCL; 88 HH), commercial livestock plus subsistence field cropping (cLsC; 109 HH) and commercial gardening plus semi-commercial livestock (cGscL; 13 HH) which had been classified in a preceding study; they represented the diversity of (peri-) urban livestock production systems in West Africa. In the study on the efficiency of ruminant livestock production, lactating cowsand sheep herd units were differentiated based on whether feed supplements were offered to the animals at the homestead (Go: grazing only; Gsf: mainly grazing plus some supplement feeding). Inflows and outflows of nutrients were quantified in these herds during 18 months, and the effects of seasonal variations in nutrient availability on animals’ productivity and reproductive performance was determined in Sikasso. To assess the safety of animal products and vegetables, contamination sources of irrigated lettuce and milk with microbiological contaminants, and of tomato and cabbage with pesticide residues in (peri-) urban agriculture systems of Bobo Dioulasso and Sikasso were characterized at three occasions in 2009. Samples of irrigation water, organic fertilizer and ix lettuce were collected in 6 gardens, and samples of cabbage and tomato in 12 gardens; raw and curdled milk were sampled in 6 dairy herds. Information on health risks for consumers of such foodstuffs was obtained from 11 health centers in Sikasso. In (peri-) urban livestock production systems, sheep and goats dominated (P<0.001) in Kano compared to Bobo Dioulasso and Sikasso, while cattle and poultry were more frequent (P<0.001) in Bobo Dioulasso and Sikasso than in Kano. Across cities, ruminant feeding relied on grazing and homestead supplementation with fresh grasses, crop residues, cereal brans and cotton seed cake; cereal grains and brans were the major ingredients of poultry feeds. There was little association of gardens and livestock; likewise field cropping and livestock were rarely integrated. No relation existed between the education of the HH head and the adoption of improved management practices (P>0.05), but the proportion of HH heads with a long-term experience in (peri-) urban agriculture was higher in Kano and in Bobo Dioulasso than in Sikasso (P<0.001). Cattle and sheep fetched highest market prices in Kano; unit prices for goats and chicken were highest in Sikasso. Animal inflow, outflow and dairy herd growth rates were significantly higher (P<0.05) in the Gsf than in the Go cattle herds. Maize bran and cottonseed expeller were the main feeds offered to Gsf cows as dry-season supplement, while Gsf sheep received maize bran, fresh grasses and cowpea pods. The short periodic transhumance of Go dairy cows help them maintaining their live weight, whereas Gsf cows lost weight during the dry season despite supplement feeding at a rate of 1506 g dry matter per cow and day, resulting in low productivity and reproductive performance. The daily live weight gains of calves and lambs, respectively, were low and not significantly different between the Go and the Gsf system. However, the average live weight gains of lambs were significantly higher in the dry season (P<0.05) than in the rainy season because of the high pressure of gastrointestinal parasites and of Trypanosoma sp. In consequence, 47% of the sheep leaving the Go and Gsf herds died due to diseases during the study period. Thermo-tolerant coliforms and Escherichia coli contamination levels of irrigation water significantly exceeded WHO recommendations for the unrestricted irrigation of vegetables consumed raw. Microbial contamination levels of lettuce at the farm gate and the market place in Bobo Dioulasso and at the farm gate in Sikasso were higher than at the market place in Sikasso (P<0.05). Pesticide residues were detected in only one cabbage and one tomato sample and were below the maximum residue limit for consumption. Counts of thermo-tolerant coliforms and Escherichia coli were higher in curdled than in raw milk (P<0.05). From 2006 to x 2009, cases of diarrhea/vomiting and typhoid fever had increased by 11% and 48%, respectively, in Sikasso. For ensuring economically successful and ecologically viable (peri-) urban livestock husbandry and food safety of (peri-) urban foodstuffs of animal and plant origin, the dissemination and adoption of improved feeding practices, livestock healthcare and dung management are key. In addition, measures fostering the safety of animal products and vegetables including the appropriate use of wastewater in (peri-) urban agriculture, restriction to approve vegetable pesticides and the respect of their latency periods, and passing and enforcement of safety laws is required. Finally, the incorporation of environmentally sound (peri-) urban agriculture in urban planning by policy makers, public and private extension agencies and the urban farmers themselves is of utmost importance. To enable an efficient (peri-) urban livestock production in the future, research should concentrate on cost-effective feeding systems that allow meeting the animals’ requirement for production and reproduction. Thereby focus should be laid on the use of crop-residues and leguminous forages. The improvement of the milk production potential through crossbreeding of local cattle breeds with exotic breeds known for their high milk yield might be an accompanying option, but it needs careful supervision to prevent the loss of the local trypanotolerant purebreds.

The environmental impact of civil conflict : the deforestation effect of paramilitary expansion in Colombia

Despite a growing body of literature on how environmental degradation can fuel civil war, the reverse effect, namely that of conflict on environmental outcomes, is relatively understudied. From a theoretical point of view this effect is ambiguous, with some forces pointing to pressures for environmental degradation and some pointing in the opposite direction. Hence, the overall effect of conflict on the environment is an empirical question. We study this relationship in the case of Colombia. We combine a detailed satellite-based longitudinal dataset on forest cover across municipalities over the period 1990-2010 with a comprehensive panel of conflict-related violent actions by paramilitary militias. We first provide evidence that paramilitary activity significantly reduces the share of forest cover in a panel specification that includes municipal and time fixed effects. Then we confirm these findings by taking advantage of a quasi-experiment that provides us with an exogenous source of variation for the expansion of the paramilitary. Using the distance to the region of Urab´a, the epicenter of such expansion, we instrument paramilitary activity in each cross-section for which data on forest cover is available. As a falsification exercise, we show that the instrument ceases to be relevant after the paramilitaries largely demobilized following peace negotiations with the government. Further, after the demobilization the deforestation effect of the paramilitaries disappears. We explore a number of potential mechanisms that may explain the conflict-driven deforestation, and show evidence suggesting that paramilitary violence generates large outflows of people in order to secure areas for growing illegal crops, exploit mineral resources, and engage in extensive agriculture. In turn, these activities are associated with deforestation.