Testing the relative sensitivity of 102 ecological variables as indicators of woodland condition in the New Forest, UK.

Forests globally are facing an increasing number of threats from modified disturbance regimes, novel stressors and changing environmental conditions. This has ultimately resulted in declines in the ecological condition of many forest and woodland ecosystems, leading to widespread tree mortality and stand dieback. Effective indicators of overall woodland ecological condition are therefore needed for environmental monitoring and to support management responses. To test the effectiveness of different variables that could potentially be used as indicators of woodland condition, 102 variables that describe woodland structure, composition, functioning, edaphic conditions and disturbance regimes were assessed along 12 replicate gradients of beech stand dieback. Results indicated that 35 variables differed significantly between at least two stages of the dieback gradient, indicating their sensitivity to stand dieback. Seven of these indicators related to woodland species composition, two to functional processes, 20 to structural features, four to edaphic conditions, and two to disturbance regimes. These results demonstrate that effective indicators can potentially be identified for each of the ecological categories. Effective composition indicators included species richness of ectomycorrhizal fungi, ground flora and epiphytic lichens; functional indicators were soil respiration rate and net nitrification rate; edaphic conditions included soil Na:Ca ratio, exchangeable sodium, total carbon, Ca:Al ratio; structural indicators included canopy openness, litter cover, sward height, and volume of deadwood, and for disturbance the indicator was Equus dung density. Other measures, such as shrub cover and species richness of carabid beetles and spiders, were not found to vary significantly along the dieback gradients, and were therefore not identified as effective indicators. These results demonstrate the value of gradient analysis for evaluating indicators of woodland condition, but also highlight the need for multi-site studies to identify indicators with widescale applicability

Characterization of Karst Terrain Using Geophysical Methods Based on Sinkhole Analysis: A Case Study of the Anina Karstic Region (Banat Mountains, Romania)

To understand karst topography, we must determine both the nature and the factors that are defining dissolution processes in soluble rocks, as well as the drainage network resulting from these processes. The goal of this paper is to understand the underground drainage direction configuration and, also, the factors that are involved in surface water drainage of the Anina karstic region. In this study we used two complementary geophysical methods, spontaneous potential (SP) and ground penetrating radar (GPR), applied in 5 sinkholes with a funnel shaped aspect. Four of these sinkholes are circular and one of them is elongated NW-SE direction. Three of the studied sinkholes are representing a chain of sinkholes orientated west-east. SP data describe the surface drainage, indicating drainage direction and/or moisture accumulation points. The GPR investigation utilizes electromagnetic pulses for the investigation of subsurface dielectric properties. GPR offers an image of the underground, showing possible bedding planes, in this case mostly along north-south orientations. Besides, in two GPR profiles, we could identify an object that could be a cavity, in that point were on SP grid the values indicate small values, pointing out a link between those two geophysical results. Using SP and GPR methods we were able to show that the bottoms of these depressions are retaining more humidity and soil. In addition, the GPR profiles outlined several subsurface “objects”, at a depth ranging between 20 and 40 meters, which need a more thorough analysis. Our future work is intended to enrich our field data using SP and GPR methods, to compare with our first results. Also, we intend to integrate electrical resistivity tomography measurements in our analysis for better subsurface characterization

Characterization of Karst Terrain Using Geophysical Methods Based on Sinkhole Analysis: A Case Study of the Anina Karstic Region (Banat Mountains, Romania)

To understand karst topography, we must determine both the nature and the factors that are defining dissolution processes in soluble rocks, as well as the drainage network resulting from these processes. The goal of this paper is to understand the underground drainage direction configuration and, also, the factors that are involved in surface water drainage of the Anina karstic region. In this study we used two complementary geophysical methods, spontaneous potential (SP) and ground penetrating radar (GPR), applied in 5 sinkholes with a funnel shaped aspect. Four of these sinkholes are circular and one of them is elongated NW-SE direction. Three of the studied sinkholes are representing a chain of sinkholes orientated west-east. SP data describe the surface drainage, indicating drainage direction and/or moisture accumulation points. The GPR investigation utilizes electromagnetic pulses for the investigation of subsurface dielectric properties. GPR offers an image of the underground, showing possible bedding planes, in this case mostly along north-south orientations. Besides, in two GPR profiles, we could identify an object that could be a cavity, in that point were on SP grid the values indicate small values, pointing out a link between those two geophysical results. Using SP and GPR methods we were able to show that the bottoms of these depressions are retaining more humidity and soil. In addition, the GPR profiles outlined several subsurface “objects”, at a depth ranging between 20 and 40 meters, which need a more thorough analysis. Our future work is intended to enrich our field data using SP and GPR methods, to compare with our first results. Also, we intend to integrate electrical resistivity tomography measurements in our analysis for better subsurface characterization

A first estimate of permafrost distribution from BTS measurements in the Romanian Carpathians (Retezat Mountains)

A first estimate of permafrost distribution in the central part of the Retezat Mountains (Southern Carpathians, Romania) was computed using basal temperature measurements of winter snow cover as input data for an empirical-statistical modelling approach. During the 2012-2013 winter season, a total of 170 bottom temperature of snow cover measurements (Haeberli, 1973) were made. The permafrost distribution within the investigated area was modelled based on multiple linear regression analysis of the relationship between bottom temperature of snow cover measurements and five predictor variables: elevation, solar radiation, vegetation cover, slope and profile curvature. The final model, having an overall accuracy of 0.48, included only the first three variables as the main factors controlling permafrost occurrence within the investigated area, while slope and profile curvature proved to be statistically insignificant. Permafrost occurrence, as predicted by the model, covers 31 km2 (52% of the investigated area), of which 14 km2 is predicted as probable permafrost and the remaining 17 km2 is possible permafrost. The obtained results indicate the importance of solar radiation, elevation and vegetation cover in controlling alpine permafrost occurrence in the central part of the Retezat Mountains.Cet article fournit une première évaluation de la distribution du pergélisol dans la partie centrale du massif de Retezat (Carpates du Sud, Roumanie), utilisant des valeurs BTS (température à la base de la neige) comme indicateur de pergélisol dans un modèle statistique. Un total de 170 points BTS a été mesuré pendant la saison hivernale 2013-2014. La distribution du pergélisol est modélisée à l’aide d’une régression linéaire multiple entre les valeurs BTS et cinq variables indépendantes : l’altitude, la radiation solaire, la végétation, la pente et la courbure du profil. L’analyse statistique montre que la pente et la courbure du profil ne sont pas significatives. Par suite, les trois autres variables ont été incluses dans le modèle final, indiquant une précision de 0,48. Ce modèle montre que le pergélisol couvre une surface de 31 km2 (52% de la zone étudiée) dont 14 km2 représentent du pergélisol probable (PRP) et 17 km2 du pergélisol possible (PP).Les résultats mettent l’accent sur l’importance de la radiation solaire, l’altitude et la végétation dans l’occurrence du pergélisol, dans la partie centrale du massif de Retezat

Time domain optical coherence tomography evaluation of polymeric fixed partial prostheses

Polymeric fixed partial prosthesis represents an important part of the prosthetic treatment. Their presence in the oral cavity could lead to fracture them and to alter the final prosthetic treatment. Time Domain Optical Coherence Tomography can be used as a noninvasive evaluation method and 3D reconstructions which could generate a real forecast on those prosthesis in the oral cavity environment

Confocal microscopy combined with time domain optical coherence tomography and micro computer tomography in interface evaluation of class II direct composite restoration

Class II cavities are often a challenge for dentists. There are a lot of procedures that can be used in order to fill this type of cavity and also a lot of problems concerning marginal adaptation, especially when composite materials are used. The aims of this study are to evaluate the integrity and marginal adaptation of class II direct composite fillings. There were used 32 samples for orthodontic reasons. Metallographic evaluation was used as the invasive methods. Micro computer tomography, confocal microscopy and optical coherence tomography were used as noninvasive methods. The conclusions pointed out the fact that noninvasive evaluation methods have great capability to accomplish a high quality characterization of the class II direct composite restorations

SEM for the general structural features assesing of the synthetic polymer scaffolds

The aim of this paper is to evaluate the possibility of Optical Coherence Tomography to diagnose the interfaces between the bone and collagen matrix in the dedicated areas. For this investigations a Time Domain OCT device was used working at 1300 nm combined with a confocal microscope that worked at 970 nm. The conclusions pointed out the possibilities of using OCT in dental direct diagnosis

New metallic nanoparticles modified adhesive used for time domain optical coherence tomography evaluation of class II direct composite restoration

Non invasive investigation in class II fillings, such as optical coherence tomography (OCT), is slowly entering in the usual dental arsenal of the direct restoration analysis. Working at more than 2 mm depth inside the samples could lead to problems related to the evaluation of the adhesive layer. At this level is difficult to point out the area with adhesive or adhesive with aerie inclusions. For this reason a new metallic Nanoparticles modified dental adhesive is used in order to increase the scattering of the normal adhesive and gain a good contrast on the OCT investigation. The validation of the results were done with SEM and EDAX procedures. In conclusion, noninvasive evaluations methods like OCT, especially OCT working in Time Domain mode, have a great capability to evaluate the interfaces between dental structure, resin fillings and dental adhesive when a metallic Nanoparticles modified adhesive is used

Integral ceramic inlay evaluation by time domain optical coherence tomography

Marginal adaptation of the integral ceramic inlays along with the ceramic integrity was investigated by a non invasive method, Optical Coherence Tomography working in Time Domain mode. Some of the samples presented a good close interface between the ceramic restorations and tooth structures. All the ceramic samples presented material defects. Optical Coherence Tomography proves its capability of a good and non invasive evaluation of the integral ceramic inlay. ceramic inlay, optical coherence tomography, marginal fit, material defect

Comparative and non-invasive study of two different ceramic materials

The purpose of this study is to investigate through imagistic methods repaired metal ceramic crowns with ceramic material. Fracture of ceramic veneer may be reconstructed with either ceramic or composite resin material. The interfaces resulted are the key of success for the longevity of these metal-ceramic repaired crowns. 20 metal ceramic crowns which restore the upper first incisor were made from Ni-Cr alloy and Kiss (D.Sign ) ceramic material. A defect of 3Ã?3 mm was made on the buccal face of each crown. The samples were divided in two groups. Each group was repaired with a different ceramic mass. Group one was repaired with In Line ceramic (Ivoclar Vivadent) and group 2 was repaired with VMK ceramic (Vita).Reparation of the crowns generated new interfaces between different materials. The interfaces were imagistic and noninvasive investigate by X-ray and Optical Coherence Tomography. The quality of the interfaces could be evaluated and also some clinical conclusions about the materials could be obtained