Search

The monitoring studies carried out in the southern Romanian Carpathians (Retezat and Bucegi - Piatra Craiului Mts) provide a scientific support for long term ecosystem research (LTER). Their general objective is to characterize the air pollution and its potential effects upon forest ecosystems’ status and biodiversity in close connection with climatic changes. Two monitoring networks were placed in selected forest ecosystems for each LTER site (11 plots in Retezat and 22 plots in Bucegi - Piatra Craiului, respectively). Both in Retezat and Bucegi - Piatra Craiului Mts, the distribution of mean ozone (O3) concentrations are significantly correlated with altitude. The location (plot) has a significant influence on ozone concentration and in some cases the exposure period along the growing season has an influence. Ambient ozone (O3) and ammonia (NH3) concentrations were below toxicity levels for forest trees, their health status (crown condition) and volume growth being insignificantly affected. More than 45% of the rain events were acidic with pH≤5.5, thus contributing to an increased N deposition on forest stands. In Retezat Mts crown condition was relatively better than in Bucegi - Piatra Craiului Mts. As a consequence, in 2009 European beech (Fagus sylvatica) was the least affected species, with a percentage of damaged trees (crown defoliation higher than 25%) between 8.0% (Retezat) and 9.8% (Bucegi - Piatra Craiului), followed by Norway spruce (Picea abies) with 12.9% (Retezat) and 27.7% (Bucegi - Piatra Craiului). The most affected species was Silver fir (Abies alba) with 31.6% of damaged trees (Bucegi-Piatra Craiului). In the last period, both European beech and conifers (Norway spruce and Silver fir) with high defoliation (damaged trees) had lower annual relative increment than trees with low defoliation (healthy trees). A definite trend regarding rapid environmental modifications is not evident and no significant reduction of biodiversity occurred. In addition, all the vegetation biodiversity components of the forest ecosystems are specific to the stand type’s structures and local climate conditions, and no quantifiable consequences of specific air pollutants on ecosystems’ diversity occurred.

Broadband dielectric spectroscopy, differential scanning calorimetry, rheology, and pulsed field gradient–nuclear magnetic resonance (PFG NMR) are combined to study glassy dynamics and charge transport in a homologous series of imidazole-based liquids with systematic variation of the alkyl chain length. The dielectric spectra are interpreted in terms of dipolar relaxation and a conductivity contribution. By applying the Einstein, Einstein–Smoluchowski, and Stokes–Einstein relations, translational diffusion coefficients—in quantitative agreement with PFG NMR measurements—are obtained. With increasing alkyl chain length, it is observed that the viscosity increases, whereas the structural α-relaxation rate decreases, in accordance with Maxwell’s relation. Between the rate ωe of electrical relaxation and the rate ωα of the structural α-relaxation, scaling is observed over more than six decades with a decoupling index of about 2. [ABSTRACT FROM AUTHOR]

Broadband dielectric and terahertz spectroscopy (10-2–10+12 Hz) are combined with pulsed field gradient nuclear magnetic resonance (PFG-NMR) to explore charge transport and translational diffusion in the 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid. The dielectric spectra are interpreted as superposition of high-frequency relaxation processes associated with dipolar librations and a conductivity contribution. The latter originates from hopping of charge carriers on a random spatially varying potential landscape and quantitatively fits the observed frequency and temperature dependence of the spectra. A further analysis delivers the hopping rate and enables one to deduce—using the Einstein–Smoluchowski equation—the translational diffusion coefficient of the charge carriers in quantitative agreement with PFG-NMR measurements. By that, the mobility is determined and separated from the charge carrier density; for the former, a Vogel–Fulcher–Tammann and for the latter, an Arrhenius temperature dependence is obtained. There is no indication of a mode arising from the reorientation of stable ion pairs. [ABSTRACT FROM AUTHOR]

Many recent studies has been indicating that academic dishonesty is more frequent in higher education, under the form plagiarism, cheating on exams, and copying assignments from other students. The present research aims to explore the relationship of personality traits, academic dishonesty and academic adjustment. The results showed that conscientiousness, honesty and openness were significantly negatively related to reports of academic dishonesty. Academic neuroticism was the most powerful predictor of cheating behaviours, while an overall high level of maladjustment predicted the positive attitudes towards academic cheating. The significant associations between academic adjustment and academic dishonesty confirmed previous research in the field. [ABSTRACT FROM AUTHOR]