113 research outputs found

    Contact mechanics analysis of a soft robotic fingerpad

    Get PDF
    The precision grasping capabilities of robotic hands is a key feature which is more and more required in the manipulation of objects in several unstructured fields, as for instance industrial, medical, agriculture and food industry. For this purpose, the realization of soft robotic fingers is crucial to reproduce the human finger skills. From this point of view the fingerpad is the part which is mostly involved in the contact. Particular attention must be paid to the knowledge of the mechanical contact behavior of soft artificial fingerpads. In this paper, artificial silicone fingerpads are applied to the last phalanx of robotic fingers actuated by tendons. The mechanical interaction between the fingerpad and a flat surface is analyzed in terms of deformations, contact areas and indentations. A reliable model of fingertip deformation properties provides important information for understanding robotic hand performance, that can be useful both in the design phase and for defining control strategies. The approach is based on theoretical, experimental, and numerical methods. The results will be exploited for the design of more effective robotic fingers for precision grasping of soft or fragile objects avoiding damages

    Root Morphology, Allometric Relations and Rhizosheath of Ancient and Modern Tetraploid Wheats (Triticum durum Desf.) in Response to Inoculation with Trichoderma harzianum T-22

    Get PDF
    Early root traits and allometrics of wheat are important for competition and use of resources. They are under-utilized in research and un-explored in many ancient wheats. This is especially true for the rhizosheath emerging from root-soil interactions. We investigated root morphology, root/shoot relations and the amount of rhizosheath of four tetrapoid wheat seedlings (30 days after emergence): the italian landrace Saragolle Lucana and modern varieties Creso, Simeto and Ciclope, and tested the hypothesis that inoculation with Trichoderma harzianum T-22 (T-22) enhances rhizosheath formation and affects wheat varieties differently. Overall growth of non-inoculated plants showed different patterns in wheat varieties, with Saragolle and Ciclope at the two extremes: Saragolle invests in shoot rather than root mass, and in the occupation of space with highest (p < 0.05) shoot height to the uppermost internode (5.02 cm) and length-to-mass shoot (97.8 cm g−1) and root (more than 140 m g−1) ratios. This may be interpreted as maximizing competition for light but also as a compensation for low shoot efficiency due to the lowest (p < 0.05) recorded values of optically-measured chlorophyll content index (22.8). Ciclope invests in biomass with highest shoot (0.06 g) and root (0.04 g) mass and a thicker root system (average diameter 0.34 mm vs. 0.29 in Saragolle) as well as a highest root/shoot ratio (0.95 g g−1 vs. 0.54 in Saragolle). Rhizosheath mass ranged between 22.14 times that of shoot mass in Ciclope and 43.40 in Saragolle (different for p < 0.05). Inoculation with Trichoderma increased the amount of rhizosheath from 9.4% in Ciclope to 36.1% in Simeto and modified root architecture in this variety more than in others. Ours are the first data on roots and seedling shoot traits of Saragolle Lucana and of Trichoderma inoculation effects on rhizosheath. This opens to new unreported interpretations of effects of Trichoderma inoculation on improving plant growth

    Genetic diversity and introgression by AFLP analisys in Phaseolus vulgaris L.

    Get PDF
    Phaseolus vulgaris L. is an economically important species whose origin is in the America continent where domestication took place and diverged in Mesoamerican and Andean gene pools. After Columbus’s voyage common bean was introduced into the Iberian Peninsula from which this species spread into the European countries and around the world. In this study investigate the extent of diversity of European germplasm compared to the American germplasm and to define the level of introgression between the European Mesoamerican and Andean gene pools are investigated. 68 accessions representative of Mesoamerican and Andean American gene pools and 241 accessions from 24 different countries belonging to an European bean core collection were analysed for three morphologic quantitative (length, height and width ) and 4 qualitative (shape, lighter colour, darker colour and coat pattern of seed) seed characters and for 4 AFLP primer combinations: E-AGT/MGAC, E-AGT/M-GTA, E-ACC/M-AGA and E-ACC/M-ATG. A total of 138 polymorphic bands were scored among the 309 accessions analysed. The European and the Mesoamerican gene pools had a number of common and very common AFLP polymorphic bands higher than the American and the Andean gene pools. The European accessions moreover were used for Structure and cpSSR analysis to identify pure and introgressed lines. These groups were compared for morphological traits and AFLP profiles. Results showed significative differences among diverse groups for morphological traits and for AFLP band frequencies, even though the diversity index were the same (He = 0.23). Hypothesis of introgression among American and European, Mesoamerican and Andean gene pools are discussed

    Nuclear and chloroplast microsatellite diversity in Phaseolus vulgaris L. from Sardinia (Italy).

    Get PDF
    Studies of the level and the structure of the genetic diversity of local varieties of Phaseolus vulgaris are of fundamental importance, both for the management of genetic resources and to improve our understanding of the pathways of dissemination and the evolution of this species in Europe. We have here characterized 73 local bean populations from Sardinia (Italy) using seed traits and molecular markers (phaseolins, nuSSRs and cpSSRs). American landraces and commercial varieties were also included for comparison. We see that: (a) the Sardinian material is distinct from the commercial varieties considered; (b) the variation in the seed traits is high and it mostly occurs among populations (95%); (c) compared to the American sample and the commercial varieties, the Sardinian collection has a low level of diversity; (d) the majority ([95%) of the Sardinian individuals belong to the Andean gene pool; (e) the Sardinian material shows a strong genetic structure, both for cpSSRs and nuSSRs; (f) the nuSSRs and cpSSRs concur in differentiating between gene pools, but a lack of congruence between nuclear and chloroplast has been observed within gene pools; and (g) there are three putative hybrids between the Andean and Mesoamerican gene pools. Despite the relatively low level of diversity, which is probably due to a strong founder effect, the Sardinian landraces are worth being conserved and studied further because of their distinctiveness and because hybridization within and between the gene pools could generate variation that will be useful for breeding

    Introduction bottleneck and the contribute of Mesoamerican and Andean gene pools to common bean (Phaseolus vulgaris L.) diversity in Europe.

    Get PDF
    Common bean (Phaseolus vulgaris L., 2n = 2x = 22) is the most important edible food legume for direct human consumption in Europe and in the world as it represents a valuable source of proteins, vitamins, fibres, and minerals. Genetic and archaeological studies have shown that domestication of P. vulgaris was originated and domesticated in the New World and has two major gene pools, the Andean and the Mesoamerican, based on their centers of origin in South and Central America, respectively. After the first voyages of Columbus (1492) common bean was brought to Europe but historical and linguistic sources provide little evidence of the introduction and expansion of common bean in Europe. In common bean a large number of nuclear microsatellite markers (nuSSRs) have been already developed and mapped that show relatively high levels of polymorphism, thus providing an attractive choice for describing population structure. However, to the best of our knowledge, population studies of the European common bean, using nuSSRs, so far have been performed with only a small number of landraces or a small number of samples from a few geographic regions. In the present study, we used thirteen highly polymorphic nuSSRs to assess the genetic structure and level of diversity of a large collection of European landraces (256 individuals), in comparison with a representative American sample (89 individuals). Moreover, to obtain a detailed picture and to elucidate the effects of bottleneck of introduction and selection for adaptation during the expansion of common bean over the whole Europe, we also complemented the nuSSRs analysis by information provided by a Bayesian analysis implemented in STRUCTURE. Here, we present and discuss the role that inter-gene pool hybridization have had in shaping the genetic structure of the European bean landraces. The implication for evolution and the advantages for common bean breeding are also discussed

    THE POTENTIAL OF PHYSIOLOGICAL ANALYSIS USING ELECTROMYOGRAPHY IN THE DESIGN OF MOTORCYCLES

    Get PDF
    Two-wheel vehicle comfort is usually assessed by means of subjective scorings or by measuring physical quantities such as acceleration, sound pressure, etc. which do not depend on the human response. This study has chosen a different approach, which is to use electromyography for evaluating the levels of muscle activity. It focuses more specifically on comfort in relation to aerodynamic loads. The loads were simulated by a wind tunnel. ANOVA statistical analysis was used to establish the impact of aerodynamic loads and of various motorcycle models on muscle activity levels. The results showed that aerodynamic loads generally cause an increase of muscle activity, although their impact varies in relation to the design of the motorcycle: each model ofmotorcycle produces a specific distribution of activity levels among muscles. The methodology can be used for vehicle-design purposes as well as organising motorbike training programmes.Keywords: Motorcycle; Aerodynamic loads; SEM; Ergonomics; Comfor

    Multivariant Assertion-based Guidance in Abstract Interpretation

    Full text link
    Approximations during program analysis are a necessary evil, as they ensure essential properties, such as soundness and termination of the analysis, but they also imply not always producing useful results. Automatic techniques have been studied to prevent precision loss, typically at the expense of larger resource consumption. In both cases (i.e., when analysis produces inaccurate results and when resource consumption is too high), it is necessary to have some means for users to provide information to guide analysis and thus improve precision and/or performance. We present techniques for supporting within an abstract interpretation framework a rich set of assertions that can deal with multivariance/context-sensitivity, and can handle different run-time semantics for those assertions that cannot be discharged at compile time. We show how the proposed approach can be applied to both improving precision and accelerating analysis. We also provide some formal results on the effects of such assertions on the analysis results.Comment: Pre-proceedings paper presented at the 28th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2018), Frankfurt am Main, Germany, 4-6 September 2018 (arXiv:1808.03326

    Breeding effects on durum wheat traits detected using GWAS and haplotype block analysis

    Get PDF
    IntroductionThe recent boosting of genomic data in durum wheat (Triticum turgidum subsp. durum) offers the opportunity to better understand the effects of breeding on the genetic structures that regulate the expression of traits of agronomic interest. Furthermore, the identification of DNA markers useful for marker-assisted selection could also improve the reliability of technical protocols used for variety protection and registration.MethodsWithin this motivation context, 123 durum wheat accessions, classified into three groups: landraces (LR), ancient (OC) and modern cultivars (MC), were evaluated in two locations, for 34 agronomic traits, including UPOV descriptors, to assess the impact of changes that occurred during modern breeding.ResultsThe association mapping analysis, performed with 4,241 SNP markers and six multi-locus-GWAS models, revealed 28 reliable Quantitative Trait Nucleotides (QTNs) related to plant morphology and kernel-related traits. Some important genes controlling flowering time and plant height were in linkage disequilibrium (LD) decay with QTNs identified in this study. A strong association for yellow berry was found on chromosome 6A (Q.Yb-6A) in a region containing the nadh-ubiquinone oxidoreductase subunit, a gene involved in starch metabolism. The Q.Kcp-2A harbored the PPO locus, with the associated marker (Ku_c13700_1196) in LD decay with Ppo-A1 and Ppo-A2. Interestingly, the Q.FGSGls-2B.1, identified by RAC875_c34512_685 for flag leaf glaucosity, mapped less than 1 Mb from the Epistatic inhibitors of glaucousness (Iw1), thus representing a good candidate for supporting the morphological DUS traits also with molecular markers. LD haplotype block approach revealed a higher diversity, richness and length of haploblocks in MC than OC and LR (580 in LR, 585 in OC and 612 in MC), suggesting a possible effect exerted by breeding programs on genomic regions associated with the agronomic traits.DiscussionOur findings pave new ways to support the phenotypic characterization necessary for variety registration by using a panel of cost-effectiveness SNP markers associated also to the UPOV descriptors. Moreover, the panel of associated SNPs might represent a reservoir of favourable alleles to use in durum wheat breeding and genetics
    • …
    corecore