338 research outputs found

    Chapter Competizione e complessitĂ  nel sistema internazionale tra equilibri e caos

    Get PDF
    The study of complexity in world politics began painstakingly in the 1980s on the initiative of authors such as James Rosenau, and looks at different types of complexity such as non-linear interactions, the interaction between actors at different levels (turbulence), the emergence of structures. The chapter intends to analyze the contribution the study of competition processes can provide by means of the theory of dynamical systems. For this purpose, nonlinear equations derived from Richardson's and equations formulated in the framework of population theories concerning crime or terrorism are considered. Finally, the need to move on to the theory of self-organization and emergent structures is indicated

    Demographic history and reproductive output correlates with intraspecific genetic variation in seven species of Indo-Pacific mangrove crabs

    Get PDF
    The spatial distribution and the amount of intraspecific genetic variation of marine organisms are strongly influenced by many biotic and abiotic factors. Comparing biological and genetic data characterizing species living in the same habitat can help to elucidate the processes driving these variation patterns. Here, we present a comparative multispecies population genetic study on seven mangrove crabs co-occurring in the West Indian Ocean characterized by planktotrophic larvae with similar pelagic larval duration. Our main aim was to investigate whether a suite of biological, behavioural and ecological traits could affect genetic diversities of the study species in combination with historical demographic parameters. As possible current explanatory factors, we used the intertidal micro-habitat colonised by adult populations, various parameters of individual and population fecundity, and the timing of larval release. As the genetic marker, we used partial sequences of cytochrome oxidase subunit I gene. Genetic and ecological data were collected by the authors and/or gathered from primary literature. Permutational multiple regression models and ANOVA tests showed that species density and their reproductive output in combination with historical demographic parameters could explain the intraspecific genetic variation indexes across the seven species. In particular, species producing consistently less eggs per spawning event showed higher values of haplotype diversity. Moreover, Tajima's D parameters well explained the recorded values for haplotype diversity and average Îłst. We concluded that current intraspecific gene diversities in crabs inhabiting mangrove forests were affected by population fecundity as well as past demographic history. The results were also discussed in terms of management and conservation of fauna in the Western Indian Ocean mangroves

    Double labelling immunohistochemical characterization of autonomic sympathetic neurons innervating the sow retractor clitoridis muscle

    Get PDF
    Retrograde neuronal tracing and immunohistochemical methods were used to define the neurochemical content of sympathetic neurons projecting to the sow retractor clitoridis muscle (RCM). Differently from the other smooth muscles of genital organs, the RCM is an isolated muscle that is tonically contracted in the rest phase and relaxed in the active phase. This peculiarity makes it an interesting experimental model. The fluorescent tracer fast blue was injected into the RCM of three 50 kg subjects. After a one-week survival period, the ipsilateral paravertebral ganglion S1, that in a preliminary study showed the greatest number of cells projecting to the muscle, was collected from each animal. The co-existence of tyrosine hydroxylase with choline acetyltransferase, neuronal nitric oxide synthase, calcitonin gene-related peptide, leuenkephalin, neuropeptide Y, substance P and vasoactive intestinal polypeptide was studied under a fluorescent microscope on cryostat sections. Tyrosine hydroxylase was present in about 58% of the neurons projecting to the muscle and was found to be co-localized with each of the other tested substances.Within fast blue-labelled cells negative to the adrenergic marker, small populations of neurons singularly containing each of the other enzymatic markers or peptides were also observed. The present study documents the complexity of the neurochemical interactions that regulate the activity of the smooth myocytes of the RCM and their vascular components

    SbisĂ  a Firenze

    Get PDF
    Carlo Sbisà’s florentine period between 1919 and 1928 is the subject of this lecture. Ten years of training, passed as a student at Academy of Fine Arts before and then in working and attending at the art exhibitions as a painter. After a research in school’s archives is now possible to run over his training in etching under Celestino Celestini and Emilio Mazzoni Zarini togheter with his friendship with the young painter Giannino Marchig. Since 1919 to 1923 Sbisà and Marchig were very close and worked togheter at the same subjects and often with the same model. In 1925 an important changing starts in Sbisà’s vision of art; this changing is visible in two paintings of franciscan subjects in which composition and light begins to be more geometrical and bright like in ancient italian painting. Talk’s hypothesis for this change is Sibsa’s close relationship with the painters Bruno Bramanti and Giovanni Colacicchi, that, in a sort of “after Soffici generation”, were protagonists, through their action in “Solaria” review, of this new attention on 15th century painting

    Coordinated RNA-Seq and peptidomics identify neuropeptides and G-protein coupled receptors (GPCRs) in the large pine weevil Hylobius abietis, a major forestry pest

    Get PDF
    Hylobius abietis (Linnaeus), or large pine weevil (Coleoptera, Curculionidae), is a pest of European coniferous forests. In order to gain understanding of the functional physiology of this species, we have assembled a de novo transcriptome of H. abietis, from sequence data obtained by Next Generation Sequencing. In particular, we have identified genes encoding neuropeptides, peptide hormones and their putative G-protein coupled receptors (GPCRs) to gain insights into neuropeptide-modulated processes. The transcriptome was assembled de novo from pooled paired-end, sequence reads obtained from RNA from whole adults, gut and central nervous system tissue samples. Data analysis was performed on the transcripts obtained from the assembly including, annotation, gene ontology and functional assignment as well as transcriptome completeness assessment and KEGG pathway analysis. Pipelines were created using Bioinformatics tools and techniques for prediction and identification of neuropeptides and neuropeptide receptors. Peptidomic analysis was also carried out using a combination of MALDI-TOF as well as Q-Exactive Orbitrap mass spectrometry to confirm the identified neuropeptide. 41 putative neuropeptide families were identified in H. abietis, including Adipokinetic hormone (AKH), CAPA and DH31. Neuropeptide F, which has not been yet identified in the model beetle T. castaneum, was identified. Additionally, 24 putative neuropeptide and 9 leucine-rich repeat containing G protein coupled receptor-encoding transcripts were determined using both alignment as well as non-alignment methods. This information, submitted to the NCBI sequence read archive repository (SRA accession: SRP133355), can now be used to inform understanding of neuropeptide-modulated physiology and behaviour in H. abietis; and to develop specific neuropeptide-based tools for H. abietis control

    Chapter Nemesi tecnologica, pace distopica: l’espropriazione della pace

    Get PDF
    Umberto Gori has often focused on the subject of peace, seen as the primary objective of Political Science, analysing the challenges that peacebuilding processes have to face in an international context undergoing profound change, and with aspects that could be described as dystopic. We will explore these dynamics by drawing inspiration from the way in which Ivan Illich dealt with the theme of the forced medicalisation of society, a theme that presents many points of contact with the intention of imposing a distorted version of the concept of peace, where a model of peaceful coexistence is proposed, which does not arise from the development of stable harmonious relations between mutually free and independent subjects, but from an absence of conflict produced by dehumanising forms of social conditioning

    A frame bundle generalization of multisymplectic field theories

    Full text link
    This paper presents a generalization of symplectic geometry to a principal bundle over the configuration space of a classical field. This bundle, the vertically adapted linear frame bundle, is obtained by breaking the symmetry of the full linear frame bundle of the field configuration space, and it inherits a generalized symplectic structure from the full frame bundle. The geometric structure of the vertically adapted frame bundle admits vector-valued field observables and produces vector-valued Hamiltonian vector fields, from which we can define a Poisson bracket on the field observables. We show that the linear and affine multivelocity spaces and multiphase spaces for geometric field theories are associated to the vertically adapted frame bundle. In addition, the new geometry not only generalizes both the linear and the affine models of multisymplectic geometry but also resolves fundamental problems found in both multisymplectic models.Comment: LaTeX2e, 28 page

    Phylogeography of the marbled crab Pachygrapsus marmoratus (Decapoda, Grapsidae) along part of the African Mediterranean coast reveals genetic homogeneity across the Siculo-Tunisian Strait versus heterogeneity across the Gibraltar Strait

    Get PDF
    We investigate the influence of previously postulated biogeographic barriers in the Mediterranean Sea on the population genetic structure of a highly dispersive and continuously distributed coastal species. In particular, we examine nuclear and mitochondrial genetic variation in the marbled crab, Pachygrapsus marmoratus, across part of the African Mediterranean coast in order to assess the influence of the Siculo-Tunisian Strait on its population genetic structure. Four polymorphic microsatellite loci were genotyped for 110 individuals, collected from eight locations covering parts of the Algerian, Tunisian and Libyan coasts. In addition, mtDNA corresponding to the Cox1 gene was sequenced for 80 samples. The corresponding results show contrasting patterns of genetic differentiation. While mtDNA results revealed a homogeneous haplotype composition in our study area, microsatellite data depicted genetic differentiation among populations, but not associated with any geographic barrier. This pattern, already recorded for this species from different geographic regions, may hint at the involvement of a complex series of abiotic and biotic factors in determining genetic structure. Demographic history reconstruction, inferred from mtDNA data, supports demographic and spatial expansion for the North African metapopulation dating back to the Mid-Pleistocene and following an historical bottleneck. Comparison of these African mitochondrial sequences with new sequences from a Turkish population and previously published sequences revealed a weak but significant separation of Atlantic and Mediterranean populations across the Gibraltar Strait, which was not recorded in previous studies of this grapsid species

    On the autonomic and sensitive nervous components of digital, metacarpal and metatarsal pads of the coypu (<i>Myocastor coypus</i>)

    Get PDF
    The innervation of the coypu foot pads (digital, metacarpal and metatarsal) is represented by an autonomic and a sensitive components. The former is constituted by isolated or grouped ganglion cells located along the course of nerve bundles, while the latter is composed by free and encapsulated nerve endings morphologically classified as Pacini, Pacini-like and Golgi-Mazzoni corpuscles. The above named corpuscles show the typical structure and can be found isolated or grouped to organize simple and complex flower-sprays, opposite-polar corpuscles and poikilomorphous fibres. The AA. notice the morphological variability of the encapsulated receptors found in this and previous similar investigations but point out also that they are functionally mechanoreceptors and so compatible with the role of the considered anatomical district
    • …
    corecore