2,300 research outputs found

    Notes on the germination of the endangered species Sclerolaena napiformis (Chenopodiaceae)

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    Sclerolaena napiformis is found on fertile plains in northern Victoria and southern New South Wales and is endangered Australia-wide. Introductory work on its germination shows that seeds cannot germinate until the woody fruit has broken down. The seeds tolerate a wide range of temperatures for germination, suggesting that germination occurs regardless of season if sufficient rain falls. Seed ageing effects reduce seed viability, but some seed is still viable after two years storage. Flower buds first appear 21 weeks from germination and some fruits have matured by week 29. In the field, plants die back to their taproots in late autumn and resprout in spring. Ninety percent of tagged plants were still alive two years later. The physiological seed dormancy imposed by an intact fruit wall provides a mechanism for the development of persistent soil seed banks. Work on the ecological significance of such banks is needed. The literature on interactions between Sclerolaena fruit and seed biology and ants is briefly reviewed

    You don't have to be poor to be an artist: Rejecting the old ways of the London Art market, many artists are starting their own alternative business models

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    The study for this MRes thesis investigates London’s contemporary art market as a form of enquiry about contemporary management practices in art environments (small galleries, artist studios, online galleries) covering the main aspects of the art leadership role and extending the enquiry into the interdependence between the traditional practices in the art market and contemporary changes in society (technological, economic, financial, social), also exploring new ways for positioning art works in the market and ways of engaging the public implemented by artists. The research thereby, responds to the question of to what extent the traditional model of gallery management is continuing to serve the artist or how it is being superseded by innovative approaches employed directly by the artist. The research surveys the perspective of emerging artists on how to enter the contemporary art market, in order to evaluate if the traditional business model of commercial galleries is still current and valid. It investigates the extent to which the role of the artist is evolving and it aims towards an improved perception of the role of the art manager. First, it identifies the role of the art manager as perceived by practitioners and researchers. Secondly, it presents funding on how contemporary artists are increasingly developing an entrepreneurial perspective, employing innovative forms of business model approaches. Thirdly, it explores how art management practices are evolving and artists are employing new approaches in promoting and selling their art. The following insights can be drawn from the research. The London Art market is prolific and competitive, yet dominated by the traditional gallery model. Artists struggle to achieve recognition and support from galleries, yet their endorsement remains essential. In response to this, a new figure of “artist entrepreneur” has emerged, challenging the tradition with new ways of working and selling art. Additionally, disruptive changes in technology are enabling artists to sell in innovative ways that bypass the system

    Un insediamento di etĂ  eneolitica nella Sardegna centro-occidentale: il villaggio di cultura Monte Claro nel sito di Cuccurada, Mogoro (OR)

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    Nel sito archeologico di Cuccurada, in comune di Mogoro, è stato posto in luce, a partire dagli anni ’90 del secolo scorso, un vasto insediamento pluristratificato che ha restituito varie fasi di occupazione preistorica e protostorica dal Neolitico Recente (cultura di Ozieri), passando dall’Eneolitico (cultura di Monte Claro) sino alle Età del Bronzo e del Ferro, con momenti di rioccupazione più tarda di epoca romana e medievale. In questo lavoro si espone in dettaglio la fase insediativa di età eneolitica, a cui sono riferibili resti monumentali e manufatti pertinenti alla cultura di Monte Claro. Si presentano inediti dati stratigrafici, materiali ceramici e spunti di analisi sulla cultura Monte Claro in questa zona della Sardegna centro-occidentale.In the archaeological site of Cuccurada, in municipality of Mogoro, the research has revealed, since the 90s of the last century, a large pluristratified settlement. Various phases of prehistoric and protohistoric occupation have been recognized, from recent Neolithic (Ozieri culture), with evidences ofCopper Age (Monte Claro culture), up to the Bronze Age and Iron Age; the site was later reoccupied in Roman and medieval age. In this work we expose in detail the settlement phase of the Copper Age, to which monumental remains and artifacts pertinent to the Monte Claro culture are referable. We present unpublished stratigraphical data, ceramic materials and new elements ofanalysis about the cultural phase ofMonte Claro in this zone ofcentral-western Sardinia

    A 3D Ferrite Coil Receiver for Wireless Power Supply of Endoscopic Capsules

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    AbstractTo expand capsular endoscopy from a mere passive screening tool towards a multipurpose robot, batteries become inadequate. Wireless power supply overcomes the problem of power shortage allowing the integration of high power demanding modules. This work focuses on wireless inductive power transfer and its optimization in size and materials. The ongoing development on 3D coil geometries is further refined by the introduction of a laser machined ferrite core to boost the amount of available power. It is demonstrated that 330mW can be transferred to a capsule under all possible orientations, within a 0.63cm3 volume

    Chiral Anomalies via Classical and Quantum Functional Methods

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    In the quantum path integral formulation of a field theory model an anomaly arises when the functional measure is not invariant under a symmetry transformation of the Lagrangian. In this paper, generalizing previous work done on the point particle, we show that even at the classical level we can give a path integral formulation for any field theory model. Since classical mechanics cannot be affected by anomalies, the measure of the classical path integral of a field theory must be invariant under the symmetry. The classical path integral measure contains the fields of the quantum one plus some extra auxiliary ones. So, at the classical level, there must be a sort of "cancellation" of the quantum anomaly between the original fields and the auxiliary ones. In this paper we prove in detail how this occurs for the chiral anomaly.Comment: 26 pages, Latex, misprint fixed, a dedication include

    Scattering reduction and resonant trapping of flexural waves: Two rings to rule them

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    In this paper, we discuss two problems concerning scattering and localisation of flexural waves in structured elastic plates. Firstly, we compare the scattering amplitudes of waves in a thin plate, generated by a point source, due to a single mass and to a large number of smaller masses, having the same equivalent mass and located around a circle. We show that in the second case, the scattering can be reduced, in particular in the medium-and high-frequency regimes. Secondly, we develop a homogenised model for a double-ring cluster of spring-mass resonators, connected to an elastic thin plate. We determine the conditions for which the plate exhibits vibration modes trapped between the two rings. Further, we show that the frequencies of the localised modes can be tuned by varying the geometry of the two rings and the characteristics of the resonators. The analytical results are corroborated by numerical simulations performed with independent finite element models

    Anti-BVDV activity evaluation of naphthoimidazole derivatives compared with parental imidazoquinoline compounds.

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    Background: Pestivirus genus includes animal pathogens which are involved in economic impact for the livestock industry. Among others, Bovine Viral Diarrhoea Virus (BVDV) establish a persistent infection in cattle causing a long list of symptoms and a high mortality rate. In the last decades, we synthesised and reported a certain number of anti-BVDV compounds. Methods: In them, imidazoquinoline derivatives turned out as the most active. Their mechanism of actions has been deeply investigated, BVDV RNA-dependent RNA polymerase (RpRd) resulted as target and the way of binding was predicted in silico through three main H-bond interaction with the target. The prediction could be confirmed by target or ligand mutation. The first approach has already been performed and published confirming the in silico prediction. Results: Here, we present how the ligand chemical modification affects the anti-BVDV activity. The designed compounds were synthesised and tested against BVDV as in silico assay negative control. Conclusion: The antiviral results confirmed the predicted mechanism of action, as the newly synthesised compounds resulted not active in the in vitro BVDV infection inhibitio

    A local feature engineering strategy to improve network anomaly detection

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    The dramatic increase in devices and services that has characterized modern societies in recent decades, boosted by the exponential growth of ever faster network connections and the predominant use of wireless connection technologies, has materialized a very crucial challenge in terms of security. The anomaly-based intrusion detection systems, which for a long time have represented some of the most efficient solutions to detect intrusion attempts on a network, have to face this new and more complicated scenario. Well-known problems, such as the difficulty of distinguishing legitimate activities from illegitimate ones due to their similar characteristics and their high degree of heterogeneity, today have become even more complex, considering the increase in the network activity. After providing an extensive overview of the scenario under consideration, this work proposes a Local Feature Engineering (LFE) strategy aimed to face such problems through the adoption of a data preprocessing strategy that reduces the number of possible network event patterns, increasing at the same time their characterization. Unlike the canonical feature engineering approaches, which take into account the entire dataset, it operates locally in the feature space of each single event. The experiments conducted on real-world data showed that this strategy, which is based on the introduction of new features and the discretization of their values, improves the performance of the canonical state-of-the-art solutions

    Influencing brain waves by evoked potentials as biometric approach: taking stock of the last six years of research

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    The scientific advances of recent years have made available to anyone affordable hardware devices capable of doing something unthinkable until a few years ago, the reading of brain waves. It means that through small wearable devices it is possible to perform an electroencephalography (EEG), albeit with less potential than those offered by high-cost professional devices. Such devices make it possible for researchers a huge number of experiments that were once impossible in many areas due to the high costs of the necessary hardware. Many studies in the literature explore the use of EEG data as a biometric approach for people identification, but, unfortunately, it presents problems mainly related to the difficulty of extracting unique and stable patterns from users, despite the adoption of sophisticated techniques. An approach to face this problem is based on the evoked potentials (EPs), external stimuli applied during the EEG reading, a noninvasive technique used for many years in clinical routine, in combination with other diagnostic tests, to evaluate the electrical activity related to some areas of the brain and spinal cord to diagnose neurological disorders. In consideration of the growing number of works in the literature that combine the EEG and EP approaches for biometric purposes, this work aims to evaluate the practical feasibility of such approaches as reliable biometric instruments for user identification by surveying the state of the art of the last 6 years, also providing an overview of the elements and concepts related to this research area
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