This was to clarify dentoalveolar, skeletal and facial profile modifications induced by Fränkel II functional treatment in Class II division 1 subjects in prepubertal stages CS1-2.Evaluation of 25 caucasian subjects (15 males, 10 females), mean age 8y 11m, in vertebral stages CS1-2. The mean duration of functional treatment was 1y 11m.Prospective controlled study. The sample was evaluated at T0, start of treatment, and T1, end of Fränkel II therapy. Untreated subjects in Class II division 1 were the control group.T-test for paired data was calculated before and after treatment (P< 0.05).A statistically significant increase between T0 and T1 was obtained for SNB (p = 0.022), ANB (p <0.001), Mx/Mn differential (p = 0.001), Co-Go-Me (p = 0.014), OJ (p < 0.001), OB (p = 0.042), IMPA (p = 0.021) . OJ (p < 0.001) and OB (p = 0.003) showed a higher significant change in the Fränkel group compared to control group.The Fränkel II appliance produced, in CS1-2 subiects, significant effects in teeth position, skeletal modifications and soft tissue changes, although the pubertal growth spurt would occur at least two years later.
Carbonyl sulfide (COS) has been proposed as a promising tracer for the estimation of the gross primary productivity (GPP) from ecosystem to global scale in recent years. Despite substantial work at spatial scales from leaf to regions, the uncertainty of COS-based GPP estimates are poorly known compared to widely used GPP estimates derived from the net ecosystem CO2 exchange. One key uncertainty in this context is the leaf relative uptake (LRU) of the COS with respect to the GPP, which must be known a priori. To investigate the influence of environmental factors, like drought, on the variability of the LRU, we conducted an experiment using ecosystem flux measurements of COS, CO2 and H2O from two eddy covariance towers above a soybean field, growing a commercial cultivar and a chlorophyll deficient mutant variety, in two separate plots. Our findings suggest that the LRU does not only differ between plant varieties due to differences in the ratio of the internal to ambient CO2 mole fraction and the internal resistance to COS, but also changes in response to drought. We also found the internal resistance to COS uptake to be a significant factor in controlling the total COS flux for both varieties, but more so for the commercial cultivar. Our study indicates that species-specific differences in the LRU need to be investigated further, and that environmental stress might complicate the usage of COS as a tracer for predicting GPP at ecosystem and global scale.
Under current environmental changes, forest management is challenged to foster contrasting benefits from forests, such as continuous wood supply while preserving biomass production, biodiversity conservation, and contribution to climate change mitigation through atmospheric carbon sequestration. Although being found as globally important, estimates of long-term forest C balance are still highly uncertain. In this context, the chronosequence experiments (space-for-time substitution) might fill this gap in even-aged forests, as they represent an approach that enables the assessment of forest net C balance in the long term. In this research, we explored the dynamics of C stocks and fluxes in different forest pools throughout the rotation period (140 years) of a Pedunculate oak (Quercus robur L.) forest in Croatia. For this purpose, we selected a chronosequence that was made up of seven forest stands with different age (5, 13, 38, 53, 68, 108, and 138 years). To address the issues of uncertainty in C balance estimates, we compared net ecosystem carbon balance (NECB) estimated while using two different approaches, which we name pool-change (from C stocks) approach and component-flux (from C fluxes) approach. Overall, the pool-change approach showed higher NECB estimate, with the greatest difference being observed in younger stands (<50 years). Component-flux approach showed significantly higher uncertainty. Throughout the rotation period, managed pedunculate oak stands become a C sink early in their development phase, between the age of 13 and 35 years according to pool-change and component-flux approach, respectively. During the 140 years, oak forest provided 187.2 Mg C ha−1 (604 m3 ha−1) through thinnings and 147.9 Mg C ha−1 (477 m3 ha−1) in the final cut, while preserving, on average, 88.9 Mg C ha−1 in mineral soil down to 40 cm, 18.2 Mg C ha−1 in dead wood, and 6.0 Mg C ha−1 in the forest floor. Soil C stocks in our chronosequence did not show any age-related trend, indicating that current management practice has no negative effect on soil C stocks. Finally, under current close-to-nature forest management, Pedunculate oak forest showed to be sustainable in providing both economic and ecological ecosystem services.
Carbonyl sulfide (COS) is a promising tracer for the estimation of the gross primary productivity (GPP) from ecosystem to global scale. To investigate the influence of environmental factors, like drought, on the variability of the leaf relative uptake (LRU) of the COS flux to the GPP, we conducted an experiment using ecosystem flux measurements of COS, CO2 and H2O from two eddy covariance towers at a soybean field, growing a commercial cultivar and a chlorophyll deficient mutant variety, in two separate plots. Our findings suggest that the LRU does not only differ between plant varieties due to differences in the ratio of the internal to ambient CO2 mole fraction and the internal resistance to COS, but also changes in response to drought. We also found the internal resistance to COS uptake to be a significant factor in controlling the total COS flux for both varieties, but more so for the commercial cultivar. Our study indicates that species-specific differences in the LRU need to be investigated further, and that environmental stress might complicate the usage of COS as a universal tracer for predicting GPP on ecosystem and global scale.
Abstract Environmental DNA consists of species‐specific intracellular and extracellular fractions, whose content and information may not be similar in all environments. In forest soil, in particular, the biogeochemical fate of DNA originated by plant litter input has been extensively reviewed, but species‐specific persistence and distribution still await to be quantified. In the present work, based on the purification of extracellular and intracellular DNA fractions from forest soil samples representing 3 soil horizons at 36 randomized locations differing for stand composition (either beech‐ or spruce‐dominated, and mixed), followed by exDNA metabarcoding with the rbcL marker, we provide a clear picture of species‐specific plant DNA distribution, and explore plant community composition and diversity along the explored gradient and the soil profile. We did not find significant differences in intra‐ vs. extracellular total DNA distribution, with a progressive depletion with soil depth positively associated with soil organic C and N content and negatively associated with soil pH and mineral content. Species‐specific DNA distribution was horizontally dependent on beech and spruce basal area aboveground, while extracellular DNA showed peculiar species‐specific vertical patterns. Proportion of Fagus sylvatica DNA increased with depth in beech stand soil, and Picea abies DNA decreased in spruce stand soil, respectively, possibly linked to species‐specific differences in leaf litter decomposition dynamics and root litter contributions. Finally, our approach by metabarcoding provided a faithful, although incomplete, picture of the local plant diversity, suggesting that such technique could positively integrate traditional biodiversity inventory studies based on expert field assessments.
The pyrolysis conversion of agricultural residues into biochar and its incorporation in agricultural soil, avoids CO2 emissions providing a safe long-term soil carbon sequestration. Furthermore, biochar application to soil seems to increase nutrient stocks in the rooting zone, to reduce nutrient leaching and to improve crop yields. This study reports some preliminary results obtained using biochar in two typical Italian agricultural crops. Two field experiments were made on durum wheat (Triticum durum L.) in Central Italy and maize (Zea mays L.) in Northern Italy. In both the field experiments, an increase in yields (+ 10% and + 6% in terms of grain production, respectively) was detected after a biochar application of 10 t ha-1. A further increase in grain production (+24%) was detected when biochar was added with maize residues. The biochar dose-effect curve was studied on perennial ryegrass (Lolium perenne L.) in a pot experiment. The highest increase of dry matter (+120%) was obtained at a biochar rate of 60 t ha-1 and above this threshold, a general reduction of biomass was observed. Results demonstrate the potential of biochar applications to improve in terms of dry matter production, while pointing out the needs for long-term field studies to better understand the effects of biochar on soil.
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