Search results for "Wood"
showing 10 items of 818 documents
Colour alone matters : no predator generalization among morphs of an aposematic moth
2018
Local warning colour polymorphism, frequently observed in aposematic organisms, is evolutionarily puzzling. This is because variation in aposematic signals is expected to be selected against due to predators' difficulties associating several signals with a given unprofitable prey. One possible explanation for the existence of such variation is predator generalization, which occurs when predators learn to avoid one form and consequently avoid other sufficiently similar forms, relaxing selection for monomorphic signals. We tested this hypothesis by exposing the three different colour morphs of the aposematic wood tiger moth, Arctia plantaginis, existing in Finland to local wild-caught predato…
Heterozygote advantage and pleiotropy contribute to intraspecific color trait variability
2022
The persistence of intrapopulation phenotypic variation typically requires some form of balancing selection because drift and directional selection eventually erode genetic variation. Heterozygote advantage remains a classic explanation for the maintenance of genetic variation in the face of selection. However, examples of heterozygote advantage, other than those associated with disease resistance, are rather uncommon. Across most of its distribution, males of the aposematic moth Arctia plantaginis have two hindwing phenotypes determined by a heritable one locus-two allele polymorphism (genotypes: WW/Wy = white morph, yy = yellow morph). Using genotyped moths, we show that the presence of o…
The impact of life stage and pigment source on the evolution of novel warning signal traits
2021
Our understanding of how novel warning color traits evolve in natural populations is largely based on studies of reproductive stages and organisms with endogenously produced pigmentation. In these systems, genetic drift is often required for novel alleles to overcome strong purifying selection stemming from frequency-dependent predation and positive assortative mating. Here, we integrate data from field surveys, predation experiments, population genomics, and phenotypic correlations to explain the origin and maintenance of geographic variation in a diet-based larval pigmentation trait in the redheaded pine sawfly (Neodiprion lecontei), a pine-feeding hymenopteran. Although our experiments c…
Rivelazione e Caratterizzazione di Consorzi Microbici in Reperti Lignei Sommersi
2009
In questa lavoro sono state affrontate le problematiche relative alla valutazione dello stato di conservazione del legno archeologico sommerso (waterlogged wood) in relazione ai fattori che ne inducono il degrado. L’attenzione è stata rivolta ai processi di biodeterioramento, indotti dall’attività di alcuni microrganismi che utilizzano le componenti principali del legno, la cui identificazione è stata eseguita ricorrendo a tecniche sia colturali sia molecolari. In particolare, le tecniche molecolari che si sono rivelate di immediata applicazione per lo studio e la caratterizzazione dei microrganismi che colonizzano i beni di interesse storico artistico e i manufatti d’interesse archeologico…
Modelling and analysing oriented fibrous structures
2014
Abstract. A mathematical model for fibrous structures using a direction dependent scaling law is presented. The orientation of fibrous nets (e.g. paper) is analysed with a method based on the curvelet transform. The curvelet-based orientation analysis has been tested successfully on real data from paper samples: the major directions of fibrefibre orientation can apparently be recovered. Similar results are achieved in tests on data simulated by the new model, allowing a comparison with ground truth. peerReviewed
Characterization of three-dimensional microstructure of composite materials by X-ray tomography
2016
Analysis methods for X-ray microtomographic images of short fibre composite materials were developed. The methods enable estimation of microstructural properties of the material, e.g., aspect ratio and orientation of fibres. Being based on X-ray microtomography and image analysis, the methods are nondestructive and do not require user intervention. In particular, a method for determination of the aspect ratio of fibres was first developed. The method contains an assumption about similarity of the shape of the fibres. The assumption was relaxed in an improved method that can estimate cross-sectional properties of fibres, too, e.g., cross-sectional area. Additionally, the effect of finite ima…
Numerical analysis of the mechanical response of wood glulam beams reinforced through the thickness by FRP rods
2009
The modern use of through-thickness reinforcement in wood glulam (glued laminated) beams, bridging the potential delamination crack faces, has shown to be an effective technological solution to improve their interlaminar fracture strength. In this paper, the behaviour of wood glulam beams is investigated from an experimental and numerical point of view, comparing the mechanical response of unreinforced and reinforced (by FRP rods) beams subjected to four points bending tests. For the numerical analysis, a simple two-phases (joint and reinforcement) interface model has been formulated and implemented in a finite element code. In particular, the classical interface model for adhesive joint, a…
The MIMOSE Approach to Support Sustainable Forest Management Planning at Regional Scale in Mediterranean Contexts
2017
In recent decades, Mediterranean landscapes have been affected by human-induced drivers, such as land use and climate change. Forest ecosystems and landscapes have been particularly affected in mountainous regions due to limited management and stewardship, especially in remote areas. Therefore, there is a need to set up new strategies to enhance ecosystem services in forested areas which, in turn, will benefit local communities and economies. In this study, we implemented a new approach—Multiscale Mapping of Ecosystem Services (MIMOSE)—to assess ecosystem services in Mediterranean forests located in a mountainous region of Italy. We spatially assessed timber provision and carbon sequestrati…
Data from the study: Strong temporal dynamics of ecosystem services through succession
2021
We used a nation-wide forest dataset from the Swedish National Forest Inventory (NFI) and the Survey of Forest Soils and Vegetation, covering an area of 400,000 km2 of production forests. The inventory uses a regular sampling grid with a randomly selected starting point covering the whole country, with each tract being surveyed once every 5 years. The tracts, which are rectangular in shape and are of different dimensions in different parts of the country, consists of 8 (in the north) to 4 (in the south) circular sample plots. The circular plots have different radii (5-20 meters) to ensure that the variables recorded characterize the ongoing forest dynamics and management. We used only plots…