Returning Migration

The present paper studies the impact of returning migration in five cases. First, the recent case of Afghanistan is analyzed, then the Chinese case. The paper con-tinues to evaluate the impact of returning migration in the Indian, the Irish and finally the Italian case. Specific policy recommendations for the phenomenon’s occurrence in Colombia are drawn based upon the case analysis. The results sug¬gest among others that effective mechanisms for management and monitoring migration flows should be created and the linkages of the Government with its Diaspora should be improved

Preliminary study of the airborne pollen in the atmosphere of Puerto Ayora (Galapagos Islands, Ecuador)

Galapagos is an archipelago of volcanic islands located 972 km west from the continental Ecuador. They were declared by the UNESCO as a World Heritage Site and Biosphere Reserve due to their singular environmental value, where a third part of the native plants are endemic to this archipelago (Jaramillo et al., 2011). In spite of the numerous scientific studies carried out in Galapagos, there are not any aerobiological samplings being performed currently. The main objectives of this study were to install a pollen trap for detecting the presence of pollen in the atmosphere of Puerto Ayora (Santa Cruz, Galapagos Islands) and qualitatively identify the different pollen types detected during the studied period. A Durham (1946) gravimetric pollen trap was modified to turn it into a passive impact pollen trap based on Pla Dalmau (1957) modifications. It was placed on the roof of the Galapagos National School (Puerto Ayora, Santa Cruz Island) at a height of 15m above ground level. The samples were obtained by using silicone fluid as adhesive substance and glycerine gelatine as mounting mean. The pollen grains were counted in a surface of 14 x 48 mm in each sample. The pollen types were identified with the aid of the pollen guide of the Galapagos Island by Jaramillo & Trigo (2011) and the Charles Darwin Foundation pollen bank. Pollen types of endemic plants such as Darwiniothamnus sp., Passiflora foetida var. galapagensis Killip, Justicia galapagana Lindau and Castela galapageia Hook. f. were detected together with those of other native and introduced species. A high diversity of pollen types was detected, reflecting the particular vegetation of the island. This preliminary aerobiological information can be used as precedent for further studies on the pollination of native and introduced species of the Galapagos Islands, as well as for detecting possible allergic diseases in the population.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Governance and Regulation of Ride-hailing Services in Emerging Markets: Challenges, Experiences and Implications

This paper seeks to shed some light on the different considerations for regulation and governance of ride-hailing platforms in emerging markets, highlighting their positive and negative externalities. Building on an extensive review of the literature and secondary sources, we outline Ride-hailing's identified and potential effects on users (providers and consumers), incumbents, and society. Based on the welfare impacts structure, we identify the significant challenges that regulators face in understanding, monitoring, evaluating, and regulating this type of transportation innovation. Finally, the paper proposes a framework for approaching such mobility innovations from governance and regulation perspectives. In a context of exponential growth in research and innovation in urban mobility in general and Ride-hailing, a rigorous review of the literature and a critical framework for understanding governance and regulation in such services in rapidly changing contexts is a timely contribution

Ridesourcing and Travel Demand: Potential Effects of Transportation Network Companies in Bogotá

This paper proposes a modal-shift analysis methodology based on a mix of small-scale primary data and big data sources to estimate the total amount of trips that are reallocated to transportation network companies (TNCs) services in Bogotá, Colombia. The analysis is focused on the following four modes: public transportation, private vehicles, conventional taxis, and TNC services. Based on a stated preferences survey and secondary databases of travel times and costs, the paper proposes a methodology to estimate the reallocation of travel demand once TNCs start operating. Results suggests that approximately one third of public transportation trips are potentially transferred to TNCs. Moreover, potential taxi and private vehicle–transferred trips account for almost 30% of the new TNC demand. Additionally, approximately half of the trips that are reallocated from public transport demand can be considered as complementary, while the remaining share can be considered as potential replacing trips of public transportation. The paper also estimates the potential increase in Vehicle-km travelled in each of the modes before and after substitution as a proxy to the effects of demand reallocation on sustainability, finding increases between 1.3 and 14.5 times the number of Vehicle-km depending on the mode. The paper highlights the role of open data and critical perspectives on available information to analyze potential scenarios of the introduction of disruptive technologies and their spatial, social, and economic implications

Characterizing the degradation process of Lithium-Ion Batteries using a Similarity-Based-Modeling Approach

This article proposes a Similarity-Based-Modeling (SBM) approach capable of characterizing the degradation process of a lithium-ion (Li-ion) battery when discharged under different current rates and different State-of-Charge (SOC) ranges. The degradation process can be represented through a biexponential model. In this regard, it is possible to determine the equivalent cycle-by-cycle efficiency which has low values at the beginning of the degradation process until it reaches a higher and steady value. The lifespan of the batteries is analyzed through the use of Monte Carlo simulations which intends to represent a more realistic way of how the batteries are used.This article proposes a Similarity-Based-Modeling (SBM) approach capable of characterizing the degradation process of a lithium-ion (Li-ion) battery when discharged under different current rates and different State-of-Charge (SOC) ranges. The degradation process can be represented through a biexponential model. In this regard, it is possible to determine the equivalent cycle-by-cycle efficiency which has low values at the beginning of the degradation process until it reaches a higher and steady value. The lifespan of the batteries is analyzed through the use of Monte Carlo simulations which intends to represent a more realistic way of how the batteries are used

Resistencia a la compresión y permeabilidad de un concreto sustituyendo al cemento por cenizas de piedra de carbón (Coal Stone) y polvo de conchas de abanico (Argopecten purpuratus)

Este plan de investigación tiene por finalidad aumentar la resistencia permeabilidad de un concreto con el uso de las cenizas de piedra de carbón y el polvo de concha de abanico, ya que por antecedentes se conoce que ambos materiales pueden llegar a actuar como puzolanas. En este proyecto de investigación se obtuvo la pérdida de masa y alorimetría de los materiales mediante el análisis térmico diferencial (ATD), composición química por del ensayo de fluorescencia de rayos X (FRX), su alcalinidad para determinar su PH y la debida sustitución al 16 % por la combinación de las cenizas de piedra de carbón y polvo de concha de abanico, el cual se evaluó su posible uso puzolanico. Se obtuvo la resistencia a la compresión de las probetas de concreto patrón f´c = 210 kg/cm2 y experimental con sustitución al 16 % de cemento por la combinación de las cenizas de piedra de carbón y polvo de concha de abanico. La prueba de alcalinidad de la mezcla de cenizas de piedra de carbón y polvo de concha de abanico alcanzo un PH = 13.02, altamente alcalino.Tesi

Procedure for Selecting a Transmission Mode Dependent on the State-of-Charge and State-of-Health of a Lithium-ion Battery in Wireless Sensor Networks with Energy Harvesting Devices

Diverse methods and considerations have been proposed to manage the available energy in an efficient manner in Wireless Sensor Networks. By incorporating Energy Harvesting Devices in these type of networks it is possible to reduce the dependency of the availability of the Energy Storage Devices, particularly the lithium-ion battery. Recently, the State-of-Charge and State-of-Health of the battery have been considered as inputs for the design of the Medium- Access-Control protocols for Wireless Sensor Networks. In this article, different guidelines are proposed for the design of Medium-Access-Control protocols used in Wireless Sensor Networks with Energy Harvesting Devices considering the State-of-Charge and State-of-Health as indicators for the estimation of the transmission time of the sensor node. The proposed guidelines consider different currents used during the transmission to estimate the State-of-Charge and Stateof- Health of the battery. The incorporation of these indicators aim to improve the decision-making process of the sensor node when transmitting.Diverse methods and considerations have been proposed to manage the available energy in an efficient manner in Wireless Sensor Networks. By incorporating Energy Harvesting Devices in these type of networks it is possible to reduce the dependency of the availability of the Energy Storage Devices, particularly the lithium-ion battery. Recently, the State-of-Charge and State-of-Health of the battery have been considered as inputs for the design of the Medium- Access-Control protocols for Wireless Sensor Networks. In this article, different guidelines are proposed for the design of Medium-Access-Control protocols used in Wireless Sensor Networks with Energy Harvesting Devices considering the State-of-Charge and State-of-Health as indicators for the estimation of the transmission time of the sensor node. The proposed guidelines consider different currents used during the transmission to estimate the State-of-Charge and Stateof- Health of the battery. The incorporation of these indicators aim to improve the decision-making process of the sensor node when transmitting