On the Measurement and Prediction of the Out-of-Plane Displacement Surrounding Cold-Expanded Holes

Experimental measurements of the out-of-plane displacement surrounding cold-expanded holes in a 6082-T6 aluminum alloy were made with a 3D optical scanner using the technique of the encoded light-pattern projection in white light. The measured surface profiles have shown the thickness discontinuity along the hole edge due to the effect of the split in the sleeve. An analytical–numerical solution of the out-of-plane displacement is presented based on existing analytical models. Thus, the results given by the analytical model were then compared with the experimental data and with a finite element (FE)model that simulates the cold-expansion process. The location of the elastic–plastic boundary was estimated as the point at which no change in thickness was observed; a good agreement was found in the comparison of measured, FE and analytical results. The measured surface profiles agreed with those predicted by the FE model and analytical solution. The proposed experimental approach can be used together with FE analysis for predicting the radial and circumferential residual stresses in cold-expanded hole. It is quite versatile and can also be used as quality-control technique in the manufacturing processes of cold-expanded holes

Typification of the name Senecio pygmaeus (Asteraceae), with some additional taxonomic and phytogeographic remarks

A thorough research on the scientific activity of Guglielmo Gasparrini, Giovanni Gussone and Augustin Pyramus De Candolle allowed the authors to address a research in several European herbaria looking for the type of the name Senecio pygmaeus DC. The original specimen sent by Gussone and mentioned in the protologue by Candolle is still kept at G-DC and is designated as the lectotype, whilst three other herbarium sheets, preserved at NAP-GUSS, PAL and PAV herbaria respectively, in all probability belong to the same gathering, and are considered as isolectotypes. The authors provide an updated description of this taxon in order to better point out its diagnostic characters. However, further biosystematic and phytogeographic surveys are needed to ascertain the taxonomic value and the distribution range of S.pygmaeus. Indeed, it might represent just a dwarfed, salt-tolerant ecotype of S.leucanthemifolius Poir. or S.vulgarisL., hence be more widespread than previously reported, counting numerous scattered populations along the rocky shores of central and eastern Mediterranean countries

Amaryllis belladonna L. (Amaryllidaceae; Amaryllidoideae), first record as naturalised geophyte in Tunisia and North Africa

Amaryllis belladonna L. is recorded for the first time as a naturalized non-native geophyte of the Tunisian and N-African flora. Distribution and habitat, brief morphological description, as well as taxonomic notes, are provided. Original photographs are also given

Parametric analysis of transcatheter aortic valve replacement in transcatheter aortic valve replacement: evaluation of coronary flow obstruction

Transcatheter aortic valve replacement (TAVR) is increasingly being considered for use in younger patients having longer life expectancy than those who were initially treated. The TAVR-in-TAVR procedure represents an appealing strategy to treat failed transcatheter heart valves (THV) likely occurring in young patients. However, the permanent displacement of first THV can potentially compromise the coronary access and ultimately inhibit the blood flow circulation. The objective of this study was to use finite-element analysis (FEA) to quantify coronary flow in a patient who underwent TAVR-in-TAVR. A parametric investigation was carried out to determine the impact of both the implantation depth and device size on coronary flow for several deployment configurations. The FEAs consisted of first delivering the SAPIEN 3 Ultra THV and then positioning the Evolut PRO device. Findings indicates that high implantation depth and device undersize of the second THV could significantly reduce coronary flow to 20% of its estimated level before TAVR. Additionally, a positive correlation was observed between coronary flow and the valve-to-coronary distance (R = 0.86 and p = 0.032 for the left coronary artery, and R = 0.93 and p = 0.014 for the right coronary artery). This study demonstrated that computational modeling can provide valuable insights to improve the pre-procedural planning of TAVR-in-TAVR

Carbon storage of Mediterranean grasslands

Secondary grasslands are one of the most common vegetation types worldwide. In Europe, and in the Mediterranean basin, human activities have transformed many woodlands into secondary grasslands. Despite their recognized role in the global carbon cycle, very few data are available for estimating the biomass of Mediterranean grasslands. We developed linear regression models in order to predict the biomass of two native Mediterranean grasses (Ampelodesmos mauritanicus and Hyparrhenia hirta) and an invasive alien grass (Pennisetum setaceum). Ampelodesmos mauritanicus is very common throughout the Mediterranean basin, mostly on north-facing slopes, H. hirta characterizes thermo-xeric grasslands, while P. setaceum is an alien species that is rapidly spreading along coastal areas. The measured morphometric attributes of individual plants as potential predictors were considered. The validation results corroborate the ability of the established models to predict above ground and total biomass of A. mauritanicus and P. setaceum. We also evaluated the total biomass per hectare for each species. The highest biomass per hectare was found for A. mauritanicus, whereas biomass was higher for H. hirta than for P. setaceum. The replacement of H. hirta by P. setaceum may reduce the total carbon storage in the ecosystem; however, P. setaceum allocates more resources to the roots, thus increasing the more stable and durable pool of carbon in grasslands

Assessing the biomass of shrubs typical of Mediterranean pre-forest communities

One of the most outstanding issues of current environmental research is the need of reliable assessments of carbon stock (i.e. above-ground (a.g.) and below-ground biomass, deadwood, litter, and organic soil matter) within forest ecosystems. Although shrub vegetation plays an important role in accumulating carbon in many Mediterranean environments, there is still very little knowledge on the carbon they store. In this article, we analyze the a.g. carbon stock of several Mediterranean shrubby communities in Sicily (Italy), dominated by Pistacia lentiscus, Chamaerops humilis, Euphorbia dendroides and Spartium junceum. Plant samples for each species were selected, and morphometric attributes (height, crown diameter, diameter at breast height, etc.) were measured to establish models for estimating a.g. biomass. Dendrometric data were also used to support the assessment of shrub biomass at community level by coupling them with the coverage of the considered woody species estimated from several hundreds of phytosociological releve´s carried out on pre-forest Sicilian communities. Although the results of such an approach have to be considered as rough assessments, the trial proves interesting, given the lack of information on stand biomass of pre-forest vegetation within the Mediterraean region.L'articolo è disponibile sul sito dell'editore http://www.tandfonline.co

Carbon storage of Mediterranean grasslands

Secondary grasslands are one of the most common vegetation types worldwide. In Europe, and in the Mediterranean basin, human activities have transformed many woodlands into secondary grasslands. Despite their recognized role in the global carbon cycle, very few data are available for estimating the biomass of Mediterranean grasslands. We developed linear regression models in order to predict the biomass of two native Mediterranean grasses (Ampelodesmos mauritanicus and Hyparrhenia hirta) and an invasive alien grass (Pennisetum setaceum). Ampelodesmos mauritanicus is very common throughout the Mediterranean basin, mostly on north-facing slopes, H. hirta characterizes thermo-xeric grasslands, while P. setaceum is an alien species that is rapidly spreading along coastal areas. The measured morphometric attributes of individual plants as potential predictors were considered. The validation results corroborate the ability of the established models to predict above ground and total biomass of A. mauritanicus and P. setaceum. We also evaluated the total biomass per hectare for each species. The highest biomass per hectare was found for A. mauritanicus, whereas biomass was higher for H. hirta than for P. setaceum. The replacement of H. hirta by P. setaceum may reduce the total carbon storage in the ecosystem; however, P. setaceum allocates more resources to the roots, thus increasing the more stable and durable pool of carbon in grasslands

The alien vascular flora of Linosa (Pelagie Islands, Strait of Sicily): update and management proposals

This paper provides an up-to-date overview of the naturalized alien plants of Linosa (Pelagie Archipelago, Sicily), which includes 83 taxa and accounts for 29 % of the total island's flora. Among these plants, 6 are invasive, 49 are naturalized and 28 are casual. With respect to previous available data, our field investigations resulted in the addition of 31 new xenophytes (21 casual and 10 fully naturalized). One of these species is new to the whole European territory (Kleinia anteuphorbia), 6 of them are new to Sicily and 11 are recorded for the first time on circum-Sicilian islets. For each alien plant, we indicate the habitat where the naturalization has been observed by using the codes proposed by Natura 2000 and Corine Biotopes habitat classification. We also provide a list of 159 alien plants that are cultivated in Linosa, but currently not naturalized, in order to underline the key role played by horticulture and gardening in the introduction of exotic species. In order to address this phenomenon and its huge impact on the integrity of both the natural and the traditional rural landscape, several actions are proposed that aim at preventing, controlling and monitoring both the ongoing and the potential invasion processes

Strelitzia nicolaii Regel & Körn. (Strelitziaceae), a casual alien plant new to Northern Hemisphere

The ongoing naturalization of the blue giant paradise bird tree, Strelitzia nicolaii, is here reported for the first time for NW Sicily (Italy). Native to SE Africa, this ornamental plant was locally introduced around mid XIX century. During last two decades the first cases of pollination and dispersal have been recorded, and within last 10 years several individuals were able to establish in abandoned Citrus orchards or in private gardens subject to moderate soil management

Improving extensive green roofs for endangered ground-nesting birds

Cities are considered hotspots of biodiversity due to their high number of habitats such as ruderal areas, wastelands and masonry works hosting peculiar bio- coenoses. Urban biodiversity represents a challenging and paradigmatic case for contemporary ecology and nature conservation because a clear distinction between nature reserves and anthropogenic lands is becoming obsolete. In this context, extensive green roofs may represent suitable habitat for ground-nesting birds and wild plants, providing suitable conditions occur. In this paper, case studies are used to show how existing extensive green roofs can be improved in order to make them function as replacement habitat for endangered ground-nesting birds. The setup of an uneven topography, combined with hay spreading and seed sowing, significantly enhanced the reproductive performance of the northern lapwing (Vanellus vanel- lus), one of the most endangered ground-nesting birds in Switzerland