Search

The COVID-19 pandemic has wreaked havoc worldwide, with profound economic, environmental, and social implications. Fears about the economic situation have called attention to freight transportation performance as a derivative economic development demand. It is critical to economic growth, especially in industrialized countries with a strong positive relationship to road transport. The empirical evidence in developing countries, such as Colombia, showed that economic growth has had linked to road freight transport regardless of comparisons with other economic sectors. Thie main objective of the paper is to assess the impact caused by the COVID-19 restrictions on freight transport by road to depict the challenge between freight transport performance and economic growth. The total freight transported in 2020 was predicted based on a time series analysis considering the system's performance. As a result, in 2020, the ton of freight transported became only 40% of the predicted freight in the most critical month. The analysis can help planners implement policies to improve freight transport behavior and react during future economic downturns. Events such as the COVID-19 pandemic demonstrate that freight transportation must be fast and flexible, is crucial to act in the short term, and consider the long-term recovery. In addition, cooperation among the various economic sectors' stakeholders must be necessary., (© 2022 The Author(s).)

This study investigated the effect of marginal gap width, luting cement, and restorative material on the wear resistance of the luting cement in areas where no occlusal contact is present. Three types of resin luting cement and one resin-modified glass-ionomer cement were used with two inlay systems, a resin composite, and an all-ceramic system. Bovine enamel represented tooth structure. Toothbrush abrasion was the wear modality. Three predetermined gap widths were selected: 240 +/- 30 microns, 150 +/- 30 microns, and 60 +/- 30 microns. All specimens were thermocycled. Regardless of the luting cement or the restorative material, there was a significant difference (P < 0.05) in wear resistance of the cement among the three gap distances at both the enamel and restoration interface. Vertical wear of the luting cement at the enamel interface increased linearly with marginal gap distance when all four cements were considered together (r2 > 0.51), regardless of type of restorative material used. The resin-modified glass-ionomer cement showed the least amount of wear for all variables considered. Significant differences in wear were found between the four luting cements at wide gap distances (240 microns) at the enamel interface, regardless of type of restorative material used. No significant differences were found between the two restorative materials at the enamel interface at the three gap distances.