2,697 research outputs found

    Resting-state connectivity and functional specialization in human medial parieto-occipital cortex

    Get PDF
    According to recent models of visuo-spatial processing, the medial parieto-occipital cortex is a crucial node of the dorsal visual stream. Evidence from neurophysiological studies in monkeys has indicated that the parieto-occipital sulcus (POS) contains three functionally and cytoarchitectonically distinct areas: the visual area V6 in the fundus of the POS, and the visuo-motor areas V6Av and V6Ad in a progressively dorsal and anterior location with respect to V6. Besides different topographical organization, cytoarchitectonics, and functional properties, these three monkey areas can also be distinguished based on their patterns of cortico-cortical connections. Thanks to wide-field retinotopic mapping, areas V6 and V6Av have been also mapped in the human brain. Here, using a combined approach of resting-state functional connectivity and task-evoked activity by fMRI, we identified a new region in the anterior POS showing a pattern of functional properties and cortical connections that suggests a homology with the monkey area V6Ad. In addition, we observed distinct patterns of cortical connections associated with the human V6 and V6Av which are remarkably consistent with those showed by the anatomical tracing studies in the corresponding monkey areas. Consistent with recent models on visuo-spatial processing, our findings demonstrate a gradient of functional specialization and cortical connections within the human POS, with more posterior regions primarily dedicated to the analysis of visual attributes useful for spatial navigation and more anterior regions primarily dedicated to analyses of spatial information relevant for goal-directed action

    ADS-B/MLAT surveillance system from high altitude platform systems

    Get PDF
    In this work the potential usage of ADS-Band Wide Area Multilateration(WAM)Surveillance with High Altitude Platform Systems(HAPS)is considered.The paper investigates the possible configuration ofthesystem,thelinkbudget,thege-ometryandthelimitationduetotherandomaccesstothechannelbytheModeSSignals(capacity).ThesurveillanceperformanceoftheproposedarchitectureinaWideAreaMultilaterationcontextisevaluatedbybothsimulationandstatisticalanalysis(CramerRaoLowerBound)

    ADS-B/MLAT surveillance system from high altitude platform systems

    Get PDF
    In this work the potential usage of ADS-Band Wide Area Multilateration(WAM)Surveillance with High Altitude Platform Systems(HAPS)is considered.The paper investigates the possible configuration ofthesystem,thelinkbudget,thege-ometryandthelimitationduetotherandomaccesstothechannelbytheModeSSignals(capacity).ThesurveillanceperformanceoftheproposedarchitectureinaWideAreaMultilaterationcontextisevaluatedbybothsimulationandstatisticalanalysis(CramerRaoLowerBound)

    Clustering methods for Mode S stations: Evaluation and perspectives

    Get PDF
    Grouping of a set of Secondary Surveillance Radar (SSR) Mode S stations into functional entities called clusters has significant operational facets; it calls for a constrained optimization, an important significant constraint being the scarcity of Interrogation Identifier (II) codes. This clustering problem can be approached by two ways, i.e., integer programming methods and heuristic approaches. The definition of a general, usable decision support tool to build up and evaluate clustering strategies in any operational airspace, e.g. the one of a nation or, even more complicated, of a system such as the European one, is a very challenging task. This paper describes some steps toward this envisaged result proposing a mathematical formulation and a heuristic approach for the problem

    A bird's eye view on the role of dendritic cells in SARS-CoV-2 infection: Perspectives for immune-based vaccines

    Get PDF
    Coronavirus disease-19 (COVID-19) is a complex disorder caused by the pandemic diffusion of a novel coronavirus named SARS-CoV-2. Clinical manifestations vary from silent infection to severe pneumonia, disseminated thrombosis, multi-organ failure, and death. COVID-19 pathogenesis is still not fully elucidated, while increasing evidence suggests that disease phenotypes are strongly related to the virus-induced immune system's dysregulation. Indeed, when the virus-host cross talk is out of control, the occurrence of an aberrant systemic inflammatory reaction, named “cytokine storm,” leads to a detrimental impairment of the adaptive immune response. Dendritic cells (DCs) are the most potent antigen-presenting cells able to support innate immune and promote adaptive responses. Besides, DCs play a key role in the anti-viral defense. The aim of this review is to focus on DC involvement in SARS-CoV-2 infection to better understand pathogenesis and clinical behavior of COVID-19 and explore potential implications for immune-based therapy strategies

    The role of internal resources in the competitive positioning of Sicilian wine cooperatives

    Get PDF
    The paper is an original article that uses accounting frameworks to determine what creates a competitive advantage in a cooperative business model. In particular, it investigates the influence of tangible, intangible and financial resources on the business performance of cooperatives operating in the Sicilian wine industry, with the RBV of the firms as a theoretical background. Using a linear regression model, our results show that tangible and financial resources are a source of a sustained competitive advantage. This study fills the gap existing in the strategic management literature related to the role of resources, tangible and intangible, in the cooperative system, providing both theoretical and practical implications

    Adoption of ubiquitous crm for operational sustainability of the firms: Moderating role of technology turbulence

    Get PDF
    Ubiquitous CRM (UCRM) enhances customer relationship management. It can sense customer needs and demands, to which firms can respond quickly. Therefore, UCRM helps to improve a firm’s agility. There is a growing interest among researchers and practitioners to understand how the adoption of UCRM impacts the sustainability of firms’ operations, but not many studies have investigated this issue. In this context, the aim of this study is to examine how firms’ absorptive capacity and dynamic capability could impact the adoption of UCRM to influence the operational sustainability of the firms and their performance. The study also investigates the moderating role of technology turbulence on the relationship between a firm’s operational sustainability and its per-formance. Using absorptive capacity theory and dynamic capability view theory and reviewing the existing literature, we developed a conceptual model. The model was then validated using a structural equation modeling technique considering 309 usable respondents from different firms that use UCRM for their operational activities. The study found that firms’ absorptive capacity and dynamic capability significantly and positively impact the adoption of UCRM, which in turn significantly and positively impacts firms’ operational sustainability and improves their performance. The study also shows that there is a significant moderating role of technology turbulence on the relationship between operational sustainability and firm performance

    The influence of open innovation on firm performance

    Get PDF
    Innovation is crucial for growth and business development, and represents a reliable way through which to gain competitiveness within the marketplace. Open innovation is expressed through three different processes: the acquisition of external technology (inbound innovation); the external exploitation of technology (outbound innovation); and coupled innovation. Based on a comprehensive and systematic review of the literature best able to detect the main thematic areas of the research topic, the aim of this paper is to investigate how the paradigm of open innovation influences firm performance and to provide suggestions for future research avenues

    Dendritic Cells Are the Intriguing Players in the Puzzle of Idiopathic Pulmonary Fibrosis Pathogenesis

    Get PDF
    Idiopathic pulmonary fibrosis (IPF) is the most devastating progressive interstitial lung disease that remains refractory to treatment. Pathogenesis of IPF relies on the aberrant cross-talk between injured alveolar cells and myofibroblasts, which ultimately leads to an aberrant fibrous reaction. The contribution of the immune system to IPF remains not fully explored. Recent evidence suggests that both innate and adaptive immune responses may participate in the fibrotic process. Dendritic cells (DCs) are the most potent professional antigen-presenting cells that bridge innate and adaptive immunity. Also, they exert a crucial role in the immune surveillance of the lung, where they are strategically placed in the airway epithelium and interstitium. Immature DCs accumulate in the IPF lung close to areas of epithelial hyperplasia and fibrosis. Conversely, mature DCs are concentrated in well-organized lymphoid follicles along with T and B cells and bronchoalveolar lavage of IPF patients. We have recently shown that all sub-types of peripheral blood DCs (including conventional and plasmacytoid DCs) are severely depleted in therapy naïve IPF patients. Also, the low frequency of conventional CD1c+ DCs is predictive of a worse prognosis. The purpose of this mini-review is to focus on the main evidence on DC involvement in IPF pathogenesis. Unanswered questions and opportunities for future research ranging from a better understanding of their contribution to diagnosis and prognosis to personalized DC-based therapies will be explored

    Pollen ontogeny in Magnolia liliflora Desr

    Get PDF
    Pollen ontogeny contributes significantly to the evolutionary analysis and the understanding of the reproductive biology of seed plants. Although much research on basal angiosperms is being carried out there are still many important features about which little is known in these taxa, such as the sporophytic structures related to pollen development and morphology. In this study, pollen development of Magnolia liliflora was analyzed by optical microscopy and transmission electron microscopy. The aim of this paper was to supply data that will help characterize basal angiosperms. Microsporogenesis is of the successive type, so that tetrads are decussate or isobilateral. The callosic walls form by the centripetal growth of furrows. The secretory tapetum develops orbicules, which start to form in the microspore tetrad stage. Pollen grains are shed at the bicellular stage. The exine wall has a granular infratectum. Ultrastructural changes observed in the cytoplasm of microspores and tapetal cells are related to the development of the pollen grain wall and orbicules. Centrifugal cell plates are more usual for the successive type of microsporogenesis. The presence of the successive type of microsporogenesis with callosic walls formed by the centripetal growth of furrows could reflect the fact that the successive type in Magnoliaceae is derived from the simultaneous type. The granular infratectum of the ectexine and the presence of orbicules could indicate that this species is one of the most evolved of the genus.Fil: Galati, Beatriz Gloria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Zarlavsky, G. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Rosenfeldt, S.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Gotelli, Marina María. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
    corecore