Leaves anatomical and physiological adaptations of Vinca major ‘Variegata’ and Hedera helix L. to specific roof garden conditions

Urban agglomerations create extreme microclimates for plants, in which growth, development and survival means adaptation. Plantations expansions beyond the typical gardens to buildings, walls or other build structures were realized in many cities with a rigorous selection of plant species. Although the number of woody species well adapted to the urban environmental conditions is quite large, few species manage to grow and develop on the roofs. Two species - Vinca major ‘Variegata’ and Hedera helix, regularly used for this type of plantations in Bucharest, were selected to understand their mechanism of adaptation. A comparative study was conducted on these species, growing on a rooftop garden and at the ground level into a typical garden. Both species revealed considerable anatomical differences of the leaves. In addition, physiological determinations revealed a stronger intensity of photosynthesis, an intense transpiration and a lower respiration rate at plants grown in the roof garden

Impact of motion compensation and partial volume correction for ¹⁸F-NaF PET/CT imaging of coronary plaque

Recent studies have suggested that ¹⁸F-NaF-PET enables visualization and quantification of plaque micro-calcification in the coronary tree. However, PET imaging of plaque calcification in the coronary arteries is challenging because of the respiratory and cardiac motion as well as partial volume effects. The objective of this work is to implement an image reconstruction framework, which incorporates compensation for respiratory as well as cardiac motion (MoCo) and partial volume correction (PVC), for cardiac ¹⁸F-NaF PET imaging in PET/CT. We evaluated the effect of MoCo and PVC on the quantification of vulnerable plaques in the coronary arteries. Realistic simulations (Biograph TPTV, Biograph mCT) and phantom acquisitions (Biograph mCT) were used for these evaluations. Different uptake values in the calcified plaques were evaluated in the simulations, while three "plaque-type" lesions of 36, 31 and 18 mm³ were included in the phantom experiments. After validation, the MoCo and PVC methods were applied in four pilot NaF-PET patient studies. In all cases, the MoCo-based image reconstruction was performed using the STIR software. The PVC was obtained from a local projection (LP) method, previously evaluated in preclinical and clinical PET. The results obtained show a significant increase of the measured lesion-to-background ratios (LBR) in the MoCo+PVC images. These ratios were further enhanced when using directly the tissue-activities from the LP method, making this approach more suitable for the quantitative evaluation of coronary plaques. When using the LP method on the MoCo images, LBR increased between 200% and 1119% in the simulated data, between 212% and 614% in the phantom experiments and between 46% and 373% in the plaques with positive uptake observed in the pilot patients. In conclusion, we have built and validated a STIR framework incorporating MoCo and PVC for ¹⁸NaF PET imaging of coronary plaques. First results indicate an improved quantification of plaque-type lesions

Worker Flows in the European Union During the Great Recession

We measure the contribution of worker flows across employment, unemployment, and non-participation to the change in unemployment in eleven EU countries during the period 2006-2012, paying special attention to which socio-demographic groups in each of the countries were mostly affected by job creation and job destruction during the crisis. We find that age, to a larger extent than educational attainments, is the main determinant of flows from employment into unemployment, particularly in those countries where unemployment increased by most. Secondly, we highlight some institutional features of the labour market (employment protection legislation, unemployment insurance, and the incidence of active labor market policies) that help to explain the cross-country differences in flows between employment and unemployment and in their socio-demographic composition. Finally, we examine if the crisis has led to some employment reallocation across sectors, finding that, so far, there is no clear evidence in favor of cleansing effects

Ionization of stark states with half-cycle pulses: Interference effects in the continuum

A detailed study of oscillations in the ionization spectrum of a Stark state in sodium excited by half-cycle pulse was carried out. Full-quantum calculations revealed oscillations in the DKD spectrum that can be explained with a 1D semiclassical model as interference effects between two dominant trajectories leading to the same final energy. On the other hand, the UKD spectra showed no oscillations due to a larger angular spread of the wave function as it scatters from the core. For the downhill state, the dependence of the oscillations on the length of the pulse was outlined