Distribution map of Ambrosia artemisiifolia L. (Asteraceae) in Italy

The spread of the invasive and allergenic Ambrosia artemisiifolia L. in Italy was analysed and mapped using distribution data from a wide range of sources. Ambrosia artemisiifolia occupies 1057 floristic quadrants which are mostly distributed in the Po plain. The distribution obtained represents the basis to implement urgent management strategies

Foam-filled energy absorbers with auxetic behaviour for localized impacts

The paper proposes an innovative concept for energy absorption in case of localized impacts. The concept is based on the contraction of cellular structures with negative Poisson's ratio under impact, which is combined with the energy absorption capability of a foam filler. An experimental assessment was accomplished considering a 3D-printed polymeric hexa-chiral frame filled with open-cell soft polyurethane foam inserts, subjected to quasi-static and dynamic indentation. The energy absorbed by the combination of the auxetic frame and foam is significantly higher than the sum of the energies absorbed by constituent elements tested separately. Based on the experiments, a numerical approach for foam-filled absorbers is developed and validated. Then non-linear models of metallic chiral units are considered in a genetic optimization process, set up to optimize the maximum frame contraction under compression before its failure. Finally, the previously validated numerical approach is applied to the optimized geometries, and it is shown that the foam filler can provide significant enhancement of specific absorbed energy and load uniformity ratio also for frames made of ductile metallic material

Quantifying the accuracy of digital hemispherical photography for LAI estimates on broad-leaved tree species

Digital hemispherical photography (DHP) has been widely used to estimate leaf area index (LAI) in forestry. Despite the advancement in the processing of hemispherical imageswith dedicated tools, several steps are still manual and thus easily affected by user\u2019s experience and sensibility. The purpose of this study was to quantify the impact of user\u2019s subjectivity on DHP LAI estimates for broad-leaved woody canopies using the software Can-Eye. Following the ISO 5725 protocol, we quantified the repeatability and reproducibility of themethod, thus defining its precision for a wide range of broad-leaved canopies markedly differing for their structure. To get a complete evaluation of the method accuracy, we also quantified its trueness using artificial canopy images with known canopy cover. Moreover, the effect of the segmentationmethod was analysed. The best results for precision (restrained limits of repeatability and reproducibility) were obtained for high LAI values (>5) with limits corresponding to a variation of 22% in the estimated LAI values. Poorer results were obtained formediumand low LAI values, with a variation of the estimated LAI values that exceeded the 40%. Regardless of the LAI range explored, satisfactory results were achieved for trees in row-structured plantations (limits almost equal to the 30% of the estimated LAI). Satisfactory resultswere achieved for trueness, regardless of the canopy structure. The paired t-test revealed that the effect of the segmentationmethod on LAI estimates was significant. Despite a non-negligible user effect, the accuracymetrics for DHP are consistent with those determined for other indirectmethods for LAI estimates, confirming the overall reliability of DHP in broad-leaved woody canopies

Functional and hierarchical interactions among zebrafish vox/vent homeobox genes

The vertebrate Vox/Vent family of transcription factors plays a crucial role in the establishment of the dorsoventral (DV) axis, by repressing organizer genes such as bozozok/dharma, goosecoid, and chordino. In Danio rerio (zebrafish), members of the vox/vent gene family (vox/vega1, vent/vega2, and ved) are thought to share expression patterns and functional properties. Bringing novel insights in the differential activity of the zebrafish vox/vent genes, we propose a critical role for the ved gene in DV patterning of vertebrate embryos. ved is not only expressed as a maternal gene, but it also appears to function as a repressor of dorsal factors involved in organizer formation. At early- and mid-gastrula stage, ved appears to be finely controlled by antagonist crosstalks in a complex regulatory network, involving gradients of bone morphogenetic protein (BMP) activity, dorsal factors, and vox/vent family members. We show that ved transcripts are ventrally restricted by BMP factors such as bmp2b, bmp7, smad5, and alk8, and by dorsal factors (chd and gsc). Alteration of ved expression in both vox and vent deletion mutants and vox and vent mRNAs-injected embryos, suggests that vox and vent function downstream of BMP signaling to negatively regulate ved expression. This inhibitory role is emphasized by a vox and vent redundant activity, compared with single gene effects

Ecological and biodiversity gradients across alpine dry grassland habitats: implications for an endangered species

Dry grasslands are of great interest for nature conservation in Europe, because they have a central role in the conservation of numerous rare and endangered species. In this study carried out in the Brenta mountain group (Italian alps), we investigated the effect of environmental factors mainly controlled by topography, on the biodiversity trends across different dry grassland habitats where the threatened alpine stenoendemic Erysimum aurantiacum grows. Plant community data and ecological factors were analysed by means of a multi-habitat CCA approach and by analysis of biodiversity gradients in 7 natural and semi-natural habitats. We found that species turnover and biodiversity patterns vary as a function of multi-factorial ecological gradients. For the single habitats, elevation gradient was the main factor explaining compositional variation, followed by inclination and proportion of exposed rock surface. Despite its endangered status, E. aurantiacum showed a relatively high degree of ecological plasticity across these semiarid grassland habitats that probably allows it to survive in different environments, including in some cases those impacted by human activities. This prompts for habitat- more than species-level conservation actions. According to their characteristics and threats, habitat-specific management practices are recommended for long term conservation of plant species communities in the different ecological niches

Regulated expression pattern of gremlin during zebrafish development

Xenopus laevis Gremlin has been isolated as a novel dorsalizing factor, belonging to a family of secreted proteins with axial patterning activity [Hsu, D.R., Economides, A.N., Wang, X., Eimon, M., Harland, R.M., 1998. The Xenopus dorsalizing factor gremlin identified a novel family of secreted proteins that antagonize BMP activities. Mol. Cell 1, 673-683]. In a search for genes that control development in zebrafish (Danio rerio), we have identified a sequence homologous to Xenopus gremlin. This paper describes the cloning of zebrafish gremlin (grm) and its expression pattern during development. Our results show that grm encodes a maternal transcript, and the zygotic transcription is turned on at the mid-blastula transition (MBT), when grm is detected in the entire blastoderm. In the gastrula grm becomes restricted to the dorsolateral region of the embryo, and during somitogenesis it is strongly expressed in the presomitic mesoderm and developing somites, and in the ventral neural tube. From 24 hpf to 48 hpf, we show that grm transcription is downregulated in the whole embryo, even though Grm protein is still present and localized into the entire myotome at 48-72 hpf. Finally, grm transcript is strongly downregulated in fibroblast growth factor-8 (fgf8) and sonic hedgehog (shh) mutants, thus implicating a putative role of Fgf/Shh signalling loop in grm expression regulation. (copyright) 2004 Elsevier B.V. All rights reserved

Design of a Leading Edge Morphing Based on Compliant Structures in the Framework of the CS2-Airgreen2 Project

This paper summarizes the results obtained in the framework of Clean Sky 2 REG-IADP, AIRGREEN on the development of a dedicated morphing device, i.e. a Leading Edge morphing. This device, designed so to be installed on a advanced, twin prop, regional aircraft, is conceived to guarantee high lift conditions together with a smoothed and continuous skin surface, especially important due to the presence of a laminar wing. The design of a such as complex devices required a multi-disciplinary approach, able to combine the aerodynamic performances and the structural ones related to the compliant structures concept adopted for the internal structure. The paper includes an overview of all the design challenges, the adopted solutions and finally the obtained numerical assessments

Identification and expression pattern of mago nashi during zebrafish development

In a search for zebrafish genes expressed during early stages of development, we have identified two ESTs encoding proteins related to Drosophila mago nashi. Zebrafish mago nashi codes for a small protein with no clearly identified functional domains, and which is highly conserved during evolution. This paper describes the identification and a detailed gene expression analysis of zebrafish mago nashi during development. Our results demonstrate that mago nashi encodes a maternal transcript detected in both blastomeres and yolk cell at the 1\u20132 cell stages, and in the blastoderm during segmentation. We show that a putative microtubule-mediated transport of mago nashi mRNA from the vegetal hemisphere into animal blastomeres determines the localization of the transcript in the animal pole, immediately after fertilization. Furthermore, the microtubule array contained into the yolk cell seems to be responsible for the high level of mago nashi transcript detected in the central blastomeres at the 8\u201316 cell stages. Zygotic mago nashi is expressed into the dorsal-marginal region during gastrulation, and starting from somitogenesis to 24 hpf, the expression domain becomes progressively restricted to the developing neural tube and paraxial structures, and ventrally to the pronephric ducts. q 2004 Elsevier B.V. All rights reserved