716 research outputs found
Openness, Similarity in Export Composition and Income Dynamics
2A relevant share of the theoretical and empirical analysis on economic growth has been devoted to finding a specific role for international trade in reinforcing countries’ growth rates. Not as much attention has been dedicated to the role of sectoral composition of export in influencing the effect of trade on income convergence. In this paper we look at this issue along the line of research on multiple regimes and convergence clubs, considering how openness and similarity in export composition among countries can induce convergence in income levels among the same countries. We apply our analysis to the catching-up of income levels of Central and Eastern Europe Countries to the EU benchmark. We explicitly consider the sectoral export patterns of the CEECs by comparing them to those of the 15 old members of the EU, focusing on countries’ specialization as suppliers for the EU market. Our main result is that similarity in export composition has a positive, significant and nonlinear impact on catching-up. Results are robust to controlling for openness and country-size and for investment, schooling, and the quality of institutions.openL. DE BENEDICTIS; TAJOLI LDE BENEDICTIS, Luca; Tajoli, L
Immigrant entrepreneurs, diasporas, and exports
This paper demonstrates the positive effect of immigrant entrepreneurs on manufacturing exports over and above that of diasporas. Using small\u2010scale regional administrative data, our instrumental variable estimates of export gravity models imply that ceteris paribus, that is, holding constant the total number of immigrants, the expected protrade effect of a migrant becoming an entrepreneur amounts to an average increase of US$5,946 in the export flows toward her country of origin. Besides these dyadic effects, immigrant entrepreneurs unlike nonentrepreneurial immigrants raise a region's overall competitiveness and export flows toward other destinations as well
The International Trade Network in Space and Time
This paper studies how the structure of the International Trade Network (ITN) changes
in geographical space and along time. We employ geographical distance between countries
in the world to filter the links in the ITN, building a sequence of sub-networks, each one
featuring trade links occurring at similar distance. We then test if the topological properties
of ITN subnetworks change as distance increases. We find that distance strongly impacts,
in non-linear ways, the topology of the ITN. We show that the ITN is disassortative at long distances while it is assortative at short ones. Similarly, the main determinant of the overall high ITN clustering level are triangular trade triples between geographically close countries.
This means that trade partnership choices are differentiated over different distance ranges.
Such evidence robustly arises over time and after one controls for the economic size and income of trading partners
Segregation with social linkages: Evaluating Schelling’s model with networked individuals
This paper generalizes the original Schelling model of racial and residential segregation to a context of variable externalities due to social linkages. In a setting in which individuals’ utility function is a convex combination of a heuristic function à la Schelling, of the distance to friends, and of the cost of moving, the prediction of the original model gets attenuated: the segregation equilibria are not the unique solutions. While the cost of distance has a monotonic pro-status-quo effect, equivalent to that of models of migration and gravity models, if friends and neighbors are formed following independent processes, the location of friends in space generates an externality that reinforces the initial configuration if the distance to friends is minimal, and if the number of friends is high. The effect on segregation equilibria crucially depends on the role played by network externalities
Network Analysis of World Trade using the BACI-CEPII dataset
In this paper we explore the BACI-CEPII database using Network Analysis. Starting from the visualization of the World Trade Network, we then define and describe the topology of the network, both in its binary version and in its weighted version, calculating and discussing some of the commonly used network's statistics. We finally discuss some specic topics that can be studied using Network Analysis and International Trade data, both at the aggregated and sectoral level. The analysis is done using multiple software (Stata, R, and Pajek). The scripts to replicate part of the analysis are included in the appendix, and can be used as an handson tutorial. Moreover,the World Trade Network local and global centrality measures, for the unweighted and the weighted version of the Network, calculated using the bilateral aggregate trade data for each country (178 in total) and each year (from 1995 to 2010,) can be downloaded from the CEPII webpage
Venous pulse wave velocity
Central venous pressure and volume status are relevant parameters for the characterization of the patient's haemodynamic condition and for the management of fluid therapy however, their invasive assessment is affected by various risks and complications while non-invasive approaches provide only imprecise and subjective indications. Aim of the present study is to explore the possibility to assess changes in venous pressure from changes in the venous pulse wave velocity (vPWV). In 9 healthy subjects, pressure pulses were generated artificially in the veins by a PC-driven rapid inflation of a pneumatic cuff (300mmHg in <1sec) placed around a foot. Passage of the pulse wave in the superficial femoral vein distally to the inguinal ligament was detected by Doppler flowmeter and the latency from the pressure stimulus was measured. The vPWV was then calculated as the ratio between traveling distance and latency. Changes in leg venous pressure were obtained by raising the trunk of the subject from the initial supine position by 30 and 60 deg. In each position 15 pressure pulses were delivered every 30 s, at the end-expiratory phase for vPWV assessment. Venous pressure in the leg was non-invasively estimated by assessing the point of collapse of the jugular or axillary vein. The vPWV increased from 1.64±0.06(supine) to 2.13±0.26 (60 deg) (Student’s t- test, p<.01) and exhibited a very strong correlation with leg venous pressure (overall r=0.76). Differences in vPWV among the three positions were statistically significant also on an individual basis in 8/9 subjects (ANOVA + Tukey's HSD post-hoc, p<.01). These preliminary results show that vPWV may be easily assessed in healthy subjects and may constitute a good non-invasive indicator of venous pressurechanges
The Effect of Cromolyn Sodium and Nedocromil Sodium Administered by A pressurized Aerosol with A spacer Device on Exercise-Induced Asthma in Children
To compare the effectiveness of cromolyn sodium (CS)
(10 mg) and nedocromil sodium (NS) (4 mg) administered
by a metered dose inhaler (MDI) with a spacer
device in preventing exercise-induced asthma (EIA), eight
asthmatic children with EIA were studied in a
randomized double-blind, cross-over, placebo-controlled
study, CS and NS provided significant, comparable protection
from EIA and both were better than placebo. We
conclude that CS and NS administered by a pressurized
aerosol with a spacer device provide equal protection
against EIA in children
Venous Pulse Wave Velocity variation in response to a simulated fluid challenge in healthy subjects
Purpose: The evaluation of a mini or simulated fluid challenge is still a complex and open issue in the clinical setting and it is of paramount significance for the fluid therapy optimization. We here investigated the capacity of a new hemodynamic parameter, the venous Pulse Wave Velocity (vPWV), to detect the effect of passive leg raising (PLR).
Materials and methods: In 15 healthy volunteers (7 M, 8 F, age 26 ± 3) venous pressure pulses were elicited by pneumatic compressions of the left hand and proximally detected by ultrasound for calculation of the vPWV. We also non-invasively measured the basilic vein (BV) cross-sectional perimeter, and peripheral venous pressure (PVP). The PLR manoeuvre was performed twice to evaluate reliability of the assessment.
Results: The PLR had an overall statistically significant effect on the entire set of variables (MANOVA, p < 0.05): vPWV increased from 2.11 ± 0.46 to 2.30 ± 0.47 m/s (p = 0.01; average increase: 10%). This effect was transient and dropped below 5% after about 3 min. A significant increase was also exhibited by BV size and PVP. In consecutive measurements vPWV showed little intra-subject variability (CoV = 8%) and good reliability (ICC = 0.87). Finally, the vPWV responses to the two PLRs exhibited good agreement (paired T-test: p = 0.96), and moderate reliability (ICC = 0.57).
Conclusion: These results demonstrated that vPWV can be non-invasively, objectively and reliably measured in healthy subjects and that it is adequate to detect small pressure/volume variations, as induced by PLR-from-supine. These characteristics make it suitable for clinical applications
A methodology for the customization of hinged ankle-foot orthoses based on in vivo helical axis calculation with 3D printed rigid shells
This study aims to develop techniques for ankle joint kinematics analysis using motion capture based on stereophotogrammetry. The scope is to design marker attachments on the skin for a most reliable identification of the instantaneous helical axis, to be targeted for the fabrication of customized hinged ankle-foot orthoses. These attachments should limit the effects of the experimental artifacts, in particular the soft-tissue motion artifact, which affect largely the accuracy of any in vivo ankle kinematics analysis. Motion analyses were carried out on two healthy subjects wearing customized rigid shells that were designed through 3D scans of the subjects’ lower limbs and fabricated by additive manufacturing. Starting from stereophotogrammetry data collected during walking and dorsi-plantarflexion motor tasks, the instantaneous and mean helical axes of ankle joint were calculated. The customized shells matched accurately the anatomy of the subjects and allowed for the definition of rigid marker clusters that improved the accuracy of in vivo kinematic analyses. The proposed methodology was able to differentiate between subjects and between the motor tasks analyzed. The observed position and dispersion of the axes were consistent with those reported in the literature. This methodology represents an effective tool for supporting the customization of hinged ankle-foot orthoses or other devices interacting with human joints functionality
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