2,698 research outputs found
Characterization of aromaticity in analogues of titan's atmospheric aerosols with two-step laser desorption ionization mass spectrometry
The role of polycyclic aromatic hydrocarbons (PAH) and Nitrogen containing
PAH (PANH) as intermediates of aerosol production in the atmosphere of Titan
has been a subject of controversy for a long time. An analysis of the
atmospheric emission band observed by the Visible and Infrared Mapping
Spectrometer (VIMS) at 3.28 micrometer suggests the presence of neutral
polycyclic aromatic species in the upper atmosphere of Titan. These molecules
are seen as the counter part of negative and positive aromatics ions suspected
by the Plasma Spectrometer onboard the Cassini spacecraft, but the low
resolution of the instrument hinders any molecular speciation.
In this work we investigate the specific aromatic content of Titan's
atmospheric aerosols through laboratory simulations. We report here the
selective detection of aromatic compounds in tholins, Titan's aerosol
analogues, produced with a capacitively coupled plasma in a N2:CH4 95:5 gas
mixture. For this purpose, Two-Step Laser Desorption Ionization Time-of-Flight
Mass Spectrometry (L2DI-TOF-MS) technique is used to analyze the so produced
analogues. This analytical technique is based on the ionization of molecules by
Resonance Enhanced Multi-Photon Ionization (REMPI) using a {\lambda}=248 nm
wavelength laser which is selective for aromatic species. This allows for the
selective identification of compounds having at least one aromatic ring. Our
experiments show that tholins contain a trace amount of small PAHs with one to
three aromatic rings. Nitrogen containing PAHs (PANHs) are also detected as
constituents of tholins. Molecules relevant to astrobiology are detected as is
the case of the substituted DNA base adenine
The Investment Climate, Competition Policy, and Economic Development in Latin America
The merits of fostering effective competition in the economy to encourage economic efficiency, consumer welfare, productivity, innovation, and attract investment have been increasingly and widely recognized by governments around the world. Relative to other regions, developing countries in Latin America have been at the forefront in adopting pro-competition measures such as deregulating industries, liberalizing trade and investment, and enacting competition (antitrust or antimonopoly) laws. However, the quality of the investment climate that determines the risks and transaction costs associated with investing and operating a business, as well as the implementation of competition law and policy, tend to vary widely across Latin American countries. This article argues that to enhance greater coherency and consistency in these policies, competition law-policy needs to be integrated as a central platform. Doing so will improve and buttress the investment climate prevailing in a country. To attain this requires increased efforts to promote better understanding of the instruments, requirements, and benefits of encouraging competition through competition advocacy —in government economic policy formulation, private sector business decisions, and civil society at large
The Investment Climate, Competition Policy, and Economic Development in Latin America
The merits of fostering effective competition in the economy to encourage economic efficiency, consumer welfare, productivity, innovation, and attract investment have been increasingly and widely recognized by governments around the world. Relative to other regions, developing countries in Latin America have been at the forefront in adopting pro-competition measures such as deregulating industries, liberalizing trade and investment, and enacting competition (antitrust or antimonopoly) laws. However, the quality of the investment climate that determines the risks and transaction costs associated with investing and operating a business, as well as the implementation of competition law and policy, tend to vary widely across Latin American countries. This article argues that to enhance greater coherency and consistency in these policies, competition law-policy needs to be integrated as a central platform. Doing so will improve and buttress the investment climate prevailing in a country. To attain this requires increased efforts to promote better understanding of the instruments, requirements, and benefits of encouraging competition through competition advocacy —in government economic policy formulation, private sector business decisions, and civil society at large
An agent-based approach for the design of the future european air traffic management system
This paper describes an agent-based approach for the simulation of air traffic management (ATM) in Europe that was designed to help analyze proposals for future ATM systems. This approach is able to represent new collaborative deci-sion processes for flow traffic management, it uses an intermediate level of ab-straction (useful for simulations at larger scales), and was designed to be a practi-cal tool (open and reusable) for the development of different ATM studies. It was successfully applied in three studies related to the design of future ATM systems in Europe
Effect of the viscosity ratio on the PLA/PA10.10 bioblends morphology and mechanical properties
PLA bio-blends with a predominantly biosourced PA10.10 in the composition range 10-50wt.% were prepared by melt blending in order to overcome the advanced brittleness of PLA. Due to the inherent immiscibility of the blends, 30 wt.% of PA was needed to achieve a brittle-to-ductile transition and a co-continuous morphology was predicted at 58 wt.% of PA. The initial enhancement of the PLA rheological behaviour through the environmentally friendly reactive extrusion process yielded a finer and more homogeneous microstructure and hence enhanced the mechanical properties of the bio-blends at much lower PA contents. The brittle-to-ductile transition could be achieved with only 10 wt.% and co-continuity was observed already at 44 wt.% of PA. Results indicate the significant potential of modifying PLA flow behaviour as a promising green manufacturing method toward expanding PLA-based bio-blends applications.Peer ReviewedPostprint (published version
Trypanosoma cruzi IIc: phylogenetic and phylogeographic insights from sequence and microsatellite analysis and potential impact on emergent Chagas disease.
Trypanosoma cruzi, the etiological agent of Chagas disease, is highly genetically diverse. Numerous lines of evidence point to the existence of six stable genetic lineages or DTUs: TcI, TcIIa, TcIIb, TcIIc, TcIId, and TcIIe. Molecular dating suggests that T. cruzi is likely to have been an endemic infection of neotropical mammalian fauna for many millions of years. Here we have applied a panel of 49 polymorphic microsatellite markers developed from the online T. cruzi genome to document genetic diversity among 53 isolates belonging to TcIIc, a lineage so far recorded almost exclusively in silvatic transmission cycles but increasingly a potential source of human infection. These data are complemented by parallel analysis of sequence variation in a fragment of the glucose-6-phosphate isomerase gene. New isolates confirm that TcIIc is associated with terrestrial transmission cycles and armadillo reservoir hosts, and demonstrate that TcIIc is far more widespread than previously thought, with a distribution at least from Western Venezuela to the Argentine Chaco. We show that TcIIc is truly a discrete T. cruzi lineage, that it could have an ancient origin and that diversity occurs within the terrestrial niche independently of the host species. We also show that spatial structure among TcIIc isolates from its principal host, the armadillo Dasypus novemcinctus, is greater than that among TcI from Didelphis spp. opossums and link this observation to differences in ecology of their respective niches. Homozygosity in TcIIc populations and some linkage indices indicate the possibility of recombination but cannot yet be effectively discriminated from a high genome-wide frequency of gene conversion. Finally, we suggest that the derived TcIIc population genetic data have a vital role in determining the origin of the epidemiologically important hybrid lineages TcIId and TcIIe
PLA/PA bio-blends: induced morphology by extrusion
The effect of processing conditions on the final morphology of Poly(Lactic Acid) (PLA) with bio-based Polyamide 10.10 (PA) 70/30 blends is analyzed in this paper. Two types of PLA were used: Commercial (neat PLA) and a rheologically modified PLA (PLAREx), with higher melt elasticity produced by reactive extrusion. To evaluate the ability of in situ micro-fibrillation (µf) of PA phase during blend compounding by twin-screw extrusion, two processing parameters were varied: (i) Screw speed rotation (rpm); and (ii) take-up velocity, to induce a hot stretching with different Draw Ratios (DR). The potential ability of PA-µf in both bio-blends was evaluated by the viscosity (p) and elasticity (k’) ratios determined from the rheological tests of pristine polymers. When PLAREx was used, the requirements for PA-µf was fulfilled in the shear rate range observed at the extrusion die. Scanning electron microscopy (SEM) observations revealed that, unlike neat PLA, PLAREx promoted PA-µf without hot stretching and the aspect ratio increased as DR increased. For neat PLA-based blends, PA-µf was promoted during the hot stretching stage. DMTA analysis revealed that the use of PLAREx PLAREx resulted in a better mechanical performance in the rubbery region (T > Tg PLA-phase) due to the PA-µf morphology obtained.Peer ReviewedPostprint (published version
An approach of the European higher education framework to the management of higher education at university level in Perú
This communication research gives an insight to University Education in Peru and a brief review of the main European documents that deal with the European Higher Education Framework, highlighting the principles upon which it is based, as well as the strategic objectives that it sets forth and the tools to achieve them. The purpose of this process is to adapt our university education management in Peru to the EEES, seeking to identify the limitations and constraints faced with regard to the keys of European convergence and the means or instruments that we have in order to attain convergence in Peru
Principios, objetivos e instrumentos de la educación superior universitaria en el Perú, para la convergencia europea
El presente documento hace un recorrido sobre la situación de la Educación Superior Universitaria en el Perú y un breve recorrido por los principales documentos europeos que se ocupan del Espacio Europeo de Educación Superior, destacando los principios sobre los que se apoya, así como los objetivos estratégicos que plantea y los instrumentos para su consecución, con la finalidad de la adaptación de nuestra gestión de la educación superior universitaria en el Perú al Espacio Europeo de Educación Superior. Se propone un proyecto de actuación con una metodología propia que la conduzca a superar estos retos y favorezca el desarrollo de la calidad, de la efectividad y de la transparencia de la educación superior universitaria en el Per
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