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Semiarid regions experience conspicuous seasonal variations, especially related to precipitation. Caves in these areas can be exceptions since they are less affected by dry seasons. In the north of the Brazilian semiarid, there are structurally heterogeneous karst areas with significant speleological potential and several anthropogenic impacts, with a neglected subterranean fauna. Therefore, we aimed to evaluate the influence of caves and external environmental features on the species richness and composition of cave invertebrates of this region. We expected that the caves would have high species richness and endemism, high dissimilarity among spatially discontinuous regions, and caves with water or guano would have greater overall richness and troglobitic species richness than those without water or guano. We collected invertebrates in 40 caves and recorded 416 species from 145 families and 45 orders (38.28 ± 13.88 spp./cave). We identified 57 species with troglomorphic traits, most having narrow distributions, including phylogenetic and/or geographic (oceanic) relicts, suggesting a lengthy and complex evolutionary history. In addition to the faunal dissimilarity among hydrographic basins and caves with or without water, our data indicate the variety of resources, the native vegetation surrounding the caves, the area, and the number of entrances as relevant variables of species composition and richness variation. Caves with water or guano had the highest richness of troglobites. The study area is unique in South America for having such a high concentration of troglobites associated with the presence of karstic aquifers and paleoclimatic changes (including oceanic transgressions and regressions), thus deserving emergency conservation actions.

Through mechanobiological control of the extracellular matrix, and hence local stiffness, smooth muscle cells of the media and fibroblasts of the adventitia play important roles in arterial homeostasis, including adaptations to altered hemodynamics, injury, and disease. We present a new approach to model arterial wall mechanics that seeks to define better the mechanical environments of the media and adventitia while avoiding the common prescription of a traction-free reference configuration. Specifically, we employ the concept of constituent-specific deposition stretches from the growth and remodeling literature and define a homeostatic state at physiologic pressure and axial stretch that serves as a convenient biologically and clinically relevant reference configuration. Information from histology and multiphoton imaging is then used to prescribe structurally motivated constitutive relations for a bi-layered model of the wall. The utility of this approach is demonstrated by describing in vitro measured biaxial pressure–diameter and axial force–length responses of murine carotid arteries and predicting the associated intact and radially cut traction-free configurations. The latter provides a unique validation while confirming that this constrained mixture approach naturally recovers estimates of residual stresses, which are fundamental to wall mechanics, without the usual need to prescribe an opening angle that is only defined conveniently on cylindrical geometries and cannot be measured in vivo . Among other findings, the model suggests that medial and adventitial stresses can be nearly uniform at physiologic loads, albeit at separate levels, and that the adventitia bears increasingly more load at supra-physiologic pressures while protecting the media from excessive stresses.

Deep metabarcoding offers an efficient and reproducible approach to biodiversity monitoring, but noisy data and incomplete reference databases challenge accurate diversity estimation and taxonomic annotation. Here, we introduce a novel algorithm, NEEAT, for removing spurious operational taxonomic units (OTUs) originating from nuclear-embedded mitochondrial DNA sequences (NUMTs) or sequencing errors. It integrates ‘echo’ signals across samples with the identification of unusual evolutionary patterns among similar DNA sequences. We also extensively benchmark current tools for chimera removal, taxonomic annotation and OTU clustering of deep metabarcoding data. The best performing tools/parameter settings are integrated into HAPP, a high-accuracy pipeline for processing deep metabarcoding data. Tests using CO1 data from BOLD and large-scale metabarcoding data on insects demonstrate that HAPP significantly outperforms existing methods, while enabling efficient analysis of extensive datasets by parallelizing computations across taxonomic groups.

Marfan syndrome (MFS) is a multi-system connective tissue disorder that results from mutations to the gene that codes the elastin-associated glycoprotein fibrillin-1. Although elastic fibers are compromised throughout the arterial tree, the most severe phenotype manifests in the ascending aorta. By comparing biaxial mechanics of the ascending and descending thoracic aorta in a mouse model of MFS, we show that aneurysmal propensity correlates well with both a marked increase in circumferential material stiffness and an increase in intramural shear stress despite a near maintenance of circumferential stress. This finding is corroborated via a comparison of the present results with previously reported findings for both the carotid artery from the same mouse model of MFS and for the thoracic aorta from another model of elastin-associated glycoprotein deficiency that does not predispose to thoracic aortic aneurysms. We submit that the unique biaxial loading of the ascending thoracic aorta conspires with fibrillin-1 deficiency to render this aortic segment vulnerable to aneurysm and rupture.

The diffusion of prepreg composite material parts is hampered by high cost of both raw material and manufacturing process. As for this latter, it is due to the manual ply-on-ply layering carried out by skilled workers. A technology that can be used to preform prepreg plies on the mould is Hot Drape Forming that is a particular thermoforming process in which a prepreg stack is heated and preformed on the mould in a single step, pressing it through an elastic membrane and vacuum. This process is suitable for complex shape parts, however it must be analysed and optimized to fulfil the stringent specifications of aeronautical industry. The aim of this work was to introduce the Hot Drape Forming (HDF) process in the production cycle of complex shape parts; in particular, an unsymmetrical L-shape part, made of carbon/epoxy prepreg, was considered as case study. After a first production test in conformity with parameter suitable for simple shape parts, some general model were considered and adapted for HDF simulation to redesign the process and to obtain a part without defects, as wrinkles, resin-rich zones and thickness irregularity. Finally, some parts were produced to confirm the validity of process optimization.

Composite materials are increasingly used for advanced applications subjected to high standards of quality that can be guaranteed by sophisticated control systems of the production process. Quality is usually controlled by monitoring temperature inside the laminate, but some researches have also evaluated the degree of cure during the thermal cycle. The goal of this work is to measure the local cure degree of thick laminates presenting a different trend as function of thickness; to achieve this aim, a suitable interdigital dielectric sensor was developed. Sensor development was carried out through FEM simulation, suited to evaluate the electric field inside the laminate: the depth of measurement of the sensor is due to its trend. The sensor was realized after having designed it and it was experimentally verified comparing the cure degree measured in a laminate polymerized in an oven with those recorded through a cure process simulation. A thick laminate was chosen because the cure degree trend is different as function of thickness and this condition is ideal to check if the sensor is able to perform local measurements.

Adventitious rooting is a quantitative genetic trait regulated by both environmental and endogenous factors. To better understand the physiological and molecular basis of adventitious rooting, we took advantage of two classes of Arabidopsis thaliana mutants altered in adventitious root formation: the superroot mutants, which spontaneously make adventitious roots, and the argonaute1 (ago1) mutants, which unlike superroot are barely able to form adventitious roots. The defect in adventitious rooting observed in ago1 correlated with light hypersensitivity and the deregulation of auxin homeostasis specifically in the apical part of the seedlings. In particular, a clear reduction in endogenous levels of free indoleacetic acid (IAA) and IAA conjugates was shown. This was correlated with a downregulation of the expression of several auxin-inducible GH3 genes in the hypocotyl of the ago1-3 mutant. We also found that the Auxin Response Factor17 (ARF17) gene, a potential repressor of auxin-inducible genes, was overexpressed in ago1-3 hypocotyls. The characterization of an ARF17-overexpressing line showed that it produced fewer adventitious roots than the wild type and retained a lower expression of GH3 genes. Thus, we suggest that ARF17 negatively regulates adventitious root formation in ago1 mutants by repressing GH3 genes and therefore perturbing auxin homeostasis in a light-dependent manner. These results suggest that ARF17 could be a major regulator of adventitious rooting in Arabidopsis.

Populus spp. are among the most economically important species worldwide. These trees are used not only for wood and fiber production, but also in the rehabilitation of degraded lands. Since they are clonally propagated, the ability of stem cuttings to form adventitious roots is a critical point for plant establishment and survival in the field, and consequently for the forest industry. Adventitious rooting in different Populus clones has been an agronomic trait targeted in breeding programs for many years, and many factors have been identified that affect this quantitative trait. A huge variation in the rooting capacity has been observed among the species in the Populus genus, and the responses to some of the factors affecting this trait have been shown to be genotype-dependent. This review analyses similarities and differences between results obtained from studies examining the role of internal and external factors affecting rooting of Populus species cuttings. Since rooting is the most important requirement for stand establishment in clonally propagated species, understanding the physiological and genetic mechanisms that promote this trait is essential for successful commercial deployment.

Collembola are major components of soil mesofauna, playing crucial roles in this environment. However, studies on this fauna in the Neotropical Region are mostly focused on taxonomy. The aim of this study was to investigate how vegetation structure influences the diversity and composition of epiedaphic Collembola assemblages across different vegetation types in Serra das Confusões National Park (PNSC), Brazil. Specimens were collected during two samplings, and were sorted, morphotyped, mounted, and identified. We performed environmental characterization, evaluated alpha and beta diversity, used the IndVal index for indicator species analysis, and conducted a Redundancy Analysis to assess the influence of environmental parameters on assemblages. We sampled 29,616 specimens, comprising 40 morphospecies and six nominal species. Our data showed significant differences between the vegetation types, with the highest abundances and richness recorded during the first sampling in the semideciduous forest, due to the dominance of taxa related to open habitats with limited moisture. The main environmental variables influencing diversity patterns were canopy cover, leaf litter height, silt percentage and soil temperature, reinforcing the dominance of species better adapted to aboveground and open habitats. We also present a comprehensive inventory of families and genera for PNSC, resulting in increased knowledge about the group in the region.

The electron beam powder bed fusion (PBF-EB) process has several advantages typical of additive manufacturing. However, at the end of the process, a large amount of powder is left that needs to be disposed of. Therefore, reusing powder for several build jobs may represent an interesting opportunity in the context of sustainable manufacturing. On the other hand, the reused powder differs from the virgin one in terms of chemical–physical characteristics due to the thermal history experienced in previous build jobs. As a consequence, the possible effects on the quality and mechanical properties of final PBF-EB parts need to be assessed to define reusing strategies that minimize these influences properly. In this study, the effect of reusing cycles on the physical/chemical properties of Ti6Al4V powder produced by plasma atomization and on the mechanical/microstructural properties of printed material was examined. The investigations showed that the powder reusing reduced the number of satellites and the porosity and induced grain coarsening. Moreover, an increase in oxygen content was found after several reusing cycles, resulting in an increase in the hardness of the printed material. The critical defect size was found to increase with reusing cycles, but no significant differences were observed in the fatigue behaviour.