El rol del transporte aéreo y el turismo en la región Litoral Argentina

The transport in all its modalities has had great importance for the development of the tourist activity. Specifically, air transport is fundamental to boost tourism, especially in those destinations where it is essential because of its geographical characteristics or the remoteness of markets that send tourists. In this sense, given the extensive geography of the Republic of Argentina and the need for agile transport, this paper aims to promote the analysis of air passenger transport under the regional context of the country with emphasis on the litoral region. The study carried out in the week of February 6 to 12, 2017 found that there is an air network of cross-country routes that connect several points of the country, and in some cases allow its link with the outside. Even so, most flights continue to be concentrated in the Buenos Aires and the connection in litoral region is deficient. El transporte en todas sus modalidades ha tenido gran importancia para el desarrollo de la actividad turística. Específicamente, el aéreo es fundamental para impulsar el turismo, sobre todo en destinos donde resulta imprescindible por sus características geográficas. En este sentido, dada la extensa geografía de la República Argentina, este trabajo pretende impulsar el análisis del transporte aéreo de pasajeros bajo el contexto regional del país, haciendo hincapié en la región Litoral. En particular se analizan los arribos a la región y algunas características del turismo. Mediante el estudio realizado en la semana del 6 al 12 de febrero de 2017 se observa que existe una red aérea de rutas que conectan destinos del país y, en algunos casos, permiten su vinculación con otros países. Aun así, continúa concentrándose la mayor parte de los vuelos en la región Buenos Aires y la conexión en la región Litoral resulta insuficiente

Event-based relaxation of continuous disordered systems

A computational approach is presented to obtain energy-minimized structures in glassy materials. This approach, the activation-relaxation technique (ART), achieves its efficiency by focusing on significant changes in the microscopic structure (events). The application of ART is illustrated with two examples: the structure of amorphous silicon, and the structure of Ni80P20, a metallic glass.Comment: 4 pages, revtex, epsf.sty, 3 figure

Role of defects in the electronic properties of amorphous/crystalline Si interface

The mechanism determining the band alignment of the amorphous/crystalline Si heterostructures is addressed with direct atomistic simulations of the interface performed using a hierarchical combination of various computational schemes ranging from classical model-potential molecular dynamics to ab-initio methods. We found that in coordination defect-free samples the band alignment is almost vanishing and independent on interface details. In defect-rich samples, instead, the band alignment is sizeably different with respect to the defect-free case, but, remarkably, almost independent on the concentration of defects. We rationalize these findings within the theory of semiconductor interfaces.Comment: 4 pages in two-column format, 2 postscript figures include

Post-functionalized iridium Zr-MOF as a promising recycle catalyst for the hydrogenation of aromatics

[EN] The multifunctional heterogeneous catalyst iridium–Zr-based MOF is able to effectively catalyze the hydrogenation of aromatic compounds in high yields under mild conditions. The catalyst was found to be highly active and reusable, giving similar reactivity and selectivity after at least five catalytic uses.We thank the MINECO of Spain (project MAT2011-29020-C02-02), Consolider-Ingenio 2010-(CSD-0050-MULTICAT). for financial support. A.M.R.A. thanks MINECO for the FPI program.Rasero Almansa, AM.; Corma Canós, A.; Iglesias, M.; Sánchez Alonso, F. (2014). Post-functionalized iridium Zr-MOF as a promising recycle catalyst for the hydrogenation of aromatics. Green Chemistry. 16(7):3522-3527. https://doi.org/10.1039/c4gc00581cS3522352716

Mixed-linker UiO-66: structure–property relationships revealed by a combination of high-resolution powder X-ray diffraction and density functional theory calculations

The use of mixed-linker metal–organic frameworks (MIXMOFs) is one of the most effective strategies to modulate the physical–chemical properties of MOFs without affecting the overall crystal structure. In many instances, MIXMOFs have been recognized as solid solutions, with random distribution of ligands, in agreement with the empirical rule known as Vegard's law. In this work, we have undertaken a study combining high-resolution powder X-ray diffraction (HR-PXRD) and density functional theory (DFT) calculations with the aim of understanding the reasons why UiO-66-based amino- and bromo-functionalized MIXMOFs (MIXUiO-66) undergo cell expansion obeying Vegard's law and how this behaviour is related to their physical–chemical properties. DFT calculations predict that the unit cell in amino-functionalized UiO-66 experiences only minor expansion as a result of steric effects, whereas major modification to the electronic features of the framework leads to weaker metal–linker interaction and consequently to the loss of stability at higher degrees of functionalization. For bromo-functionalized UiO-66, steric repulsion due to the size of bromine yields a large cell expansion, but the electronic features remain very similar to pristine UiO-66, preserving the stability of the framework upon functionalization. MIXUiO-66 obtained by either direct synthesis or by post-synthetic exchange shows Vegard-like behaviour, suggesting that both preparation methods yield solid solutions, but the thermal stability and the textural properties of the post-synthetic exchanged materials do not display a clear dependence on the chemical composition, as observed for the MOFs obtained by direct synthesis

Guillain-Barré syndrome and COVID-19: an observational multicentre study from two Italian hotspot regions

Objective: Single cases and small series of Guillain-Barré syndrome (GBS) have been reported during the SARS-CoV-2 outbreak worldwide. We evaluated incidence and clinical features of GBS in a cohort of patients from two regions of northern Italy with the highest number of patients with COVID-19. Methods: GBS cases diagnosed in 12 referral hospitals from Lombardy and Veneto in March and April 2020 were retrospectively collected. As a control population, GBS diagnosed in March and April 2019 in the same hospitals were considered. Results: Incidence of GBS in March and April 2020 was 0.202/100 000/month (estimated rate 2.43/100 000/year) vs 0.077/100 000/month (estimated rate 0.93/100 000/year) in the same months of 2019 with a 2.6-fold increase. Estimated incidence of GBS in COVID-19-positive patients was 47.9/100 000 and in the COVID-19-positive hospitalised patients was 236/100 000. COVID-19-positive patients with GBS, when compared with COVID-19-negative subjects, showed lower MRC sum score (26.3±18.3 vs 41.4±14.8, p=0.006), higher frequency of demyelinating subtype (76.6% vs 35.3%, p=0.011), more frequent low blood pressure (50% vs 11.8%, p=0.017) and higher rate of admission to intensive care unit (66.6% vs 17.6%, p=0.002). Conclusions: This study shows an increased incidence of GBS during the COVID-19 outbreak in northern Italy, supporting a pathogenic link. COVID-19-associated GBS is predominantly demyelinating and seems to be more severe than non-COVID-19 GBS, although it is likely that in some patients the systemic impairment due to COVID-19 might have contributed to the severity of the whole clinical picture