RESUMEN
Two computational approaches for computing the rates of internal conversions in molecular systems where a large set of nuclear degrees of freedom plays a role are discussed and compared. One approach is based on the numerical solution of the time-dependent Schrödinger equation and allows us to include almost the whole set of vibrational coordinates, thanks to the employment of effective procedures for selecting those elements of the Hilbert space which play a significant role in dynamics. The other approach, based on the time-dependent perturbation theory and limited to the use of the harmonic approximation, allows us to include the whole Hilbert space spanned by the vibrational states of the system. The two approaches are applied to the photophysics of azulene, whose anti-Kasha behavior caused by anomalous internal conversion rates is well assessed. The calculated rates for the decays of the first two excited singlet states are in very good agreement with experimental data, indicating the reliability of both methodologies.
RESUMEN
This study addressed the scarcity of NH3 measurements in urban Europe and the diverse monitoring protocols, hindering direct data comparison. Sixty-nine datasets from Finland, France, Italy, Spain, and the UK across various site types, including industrial (IND, 8), traffic (TR, 12), urban (UB, 22), suburban (SUB, 12), and regional background (RB, 15), are analyzed to this study. Among these, 26 sites provided 5, or more, years of data for time series analysis. Despite varied protocols, necessitating future harmonization, the average NH3 concentration across sites reached 8.0 ± 8.9 µg/m3. Excluding farming/agricultural hotspots (FAHs), IND and TR sites had the highest concentrations (4.7 ± 3.2 and 4.5 ± 1.0 µg/m3), followed by UB, SUB, and RB sites (3.3 ± 1.5, 2.7 ± 1.3, and 1.0 ± 0.3 µg/m3, respectively) indicating that industrial, traffic, and other urban sources were primary contributors to NH3 outside FAH regions. When referring exclusively to the FAHs, concentrations ranged from 10.0 ± 2.3 to 15.6 ± 17.2 µg/m3, with the highest concentrations being reached in RB sites close to the farming and agricultural sources, and that, on average for FAHs there is a decreasing NH3 concentration gradient towards the city. Time trends showed that over half of the sites (18/26) observed statistically significant trends. Approximately 50 % of UB and TR sites showed a decreasing trend, while 30 % an increasing one. Meta-analysis revealed a small insignificant decreasing trend for non-FAH RB sites. In FAHs, there was a significant upward trend at a rate of 3.51[0.45,6.57]%/yr. Seasonal patterns of NH3 concentrations varied, with urban areas experiencing fluctuations influenced by surrounding emissions, particularly in FAHs. Diel variation showed differing patterns at urban monitoring sites, all with higher daytime concentrations, but with variations in peak times depending on major emission sources and meteorological patterns. These results offer valuable insights into the spatio-temporal patterns of gas-phase NH3 concentrations in urban Europe, contributing to future efforts in benchmarking NH3 pollution control in urban areas.
Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Atmosféricos/análisis , Amoníaco/análisis , Contaminación del Aire/análisis , España , Finlandia , Europa (Continente) , Francia , Italia , Monitoreo del Ambiente/métodos , Reino UnidoRESUMEN
BACKGROUND: Hand injuries are common affecting all ages, genders, and geographic regions. They can result in long term disability and mortality, while they place a significant financial burden in society. Although, hand injuries can be prevented. Preventive strategies can be designed, but knowledge of injuries' epidemiological characteristics is required beforehand. METHODS: We performed a review of the current literature related to hand injuries to identify their incidence, patients' demographics, type, mode, and time of the injury. RESULTS: Hand injuries constitute 6.6% to 28.6% of all injuries presenting to the Emergency Department and 28% of injuries to the musculoskeletal system. They mainly affect young male labourers. Occupational and home accidents are the commonest injury modalities, while traffic road accidents constitute a significant reason for hand injuries as well. Lacerations account for most hand injuries, followed by crush injuries, fractures and amputations. Most occupational injuries occur in the beginning of the week and especially during the morning shift, while there has been identified an increase in the number of hand injuries during the summer months. CONCLUSIONS: Hand injuries are an important health problem with impact on patient's life and on the society. Although they can be prevented. Preventive strategies need to be addressed towards many directions and people's activities, since prevention will have an important impact on people's quality of life and society's well-being.