958 research outputs found

    Machine Learning Applications for Jet Tagging in the CMS Experiment

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    The fundamental physics research at the frontier accessible by today's particle accelerators such as the CERN Large Hadron Collider pose unique challenges in terms of complexity and abundance of data to analyse. In this context, it is of paramount importance to develop algorithms capable of dealing with multivariate problems to enhance humans' ability to interpret data and ultimately increase the discovery potential of the experiments. Machine learning techniques therefore assume an increasingly important role in the experiments at the LHC. In this work, we give an overview of the latest developments in this field, with a particular focus on the algorithms developed and used within the CMS Collaboration. The review follows this structure: (1) Introduction presents the CMS Experiment at LHC and the most common methods used in particle physics; (2) Jet Flavour Tagging briefly describes the main algorithms used to reconstruct heavy-flavour jets; (3) Jet Substructure and Deep Tagging focuses on the identification of heavy-particle decay in boosted jets; (4) Analysis Applications gives examples of applying the algorithm in physics analyses; and (5) Conclusions summarises the state-of-the-art and gives indications for future studies

    Constructional design of echinoid endoskeleton: main structural components and their potential for biomimetic applications

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    The endoskeleton of echinoderms (Deuterostomia: Echinodermata) is of mesodermal origin and consists of cells, organic components, as well as an inorganic mineral matrix. The echinoderm skeleton forms a complex lattice-system, which represents a model structure for naturally inspired engineering in terms of construction, mechanical behaviour and functional design. The sea urchin (Echinodermata: Echinoidea) endoskeleton consists of three main structural components: test, dental apparatus and accessory appendages. Although, all parts of the echinoid skeleton consist of the same basic material, their microstructure displays a great potential in meeting several mechanical needs according to a direct and clear structure–function relationship. This versatility has allowed the echinoid skeleton to adapt to different activities such as structural support, defence, feeding, burrowing and cleaning. Although, constrained by energy and resource efficiency, many of the structures found in the echinoid skeleton are optimized in terms of functional performances. Therefore, these structures can be used as role models for bio-inspired solutions in various industrial sectors such as building constructions, robotics, biomedical and material engineering. The present review provides an overview of previous mechanical and biomimetic research on the echinoid endoskeleton, describing the current state of knowledge and providing a reference for future studies

    Structure of human NMN adenylyltransferase. A key nuclear enzyme for NAD homeostasis.

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    Abstract Nicotinamide mononucleotide adenylyltransferase (NMNAT), a member of the nucleotidyltransferase α/β-phosphodiesterases superfamily, catalyzes a universal step (NMN + ATP = NAD + PPi) in NAD biosynthesis. Localized within the nucleus, the activity of the human enzyme is greatly altered in tumor cells, rendering it a promising target for cancer chemotherapy. By using a combination of single isomorphous replacement and density modification techniques, the human NMNAT structure was solved by x-ray crystallography to a 2.5-A resolution, revealing a hexamer that is composed of α/β-topology subunits. The active site topology of the enzyme, analyzed through homology modeling and structural comparison with other NMNATs, yielded convincing evidence for a substrate-induced conformational change. We also observed remarkable structural conservation in the ATP-recognition motifs GXXXPX(T/H)XXH and SXTXXR, which we take to be the universal signature for NMNATs. Structural comparison of human and prokaryotic NMNATs may also lead to the rational design of highly selective antimicrobial drugs

    Flexible sutures reduce bending moments in shells: from the echinoid test to tessellated shell structures

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    In the field of structural engineering, lightweight and resistant shell structures can be designed by efficiently integrating and optimizing form, structure and function to achieve the capability to sustain a variety of loading conditions with a reduced use of resources. Interestingly, a limitless variety of high-performance shell structures can be found in nature. Their study can lead to the acquisition of new functional solutions that can be employed to design innovative bioinspired constructions. In this framework, the present study aimed to illustrate the main results obtained in the mechanical analysis of the echinoid test in the common sea urchin Paracentrotus lividus (Lamarck, 1816) and to employ its principles to design lightweight shell structures. For this purpose, visual survey, photogrammetry, three-dimensional modelling, three-point bending tests and finite-element modelling were used to interpret the mechanical behaviour of the tessellated structure that characterize the echinoid test. The results achieved demonstrated that this structural topology, consisting of rigid plates joined by flexible sutures, allows for a significant reduction of bending moments. This strategy was generalized and applied to design both freeform and form-found shell structures for architecture exhibiting improved structural efficiency

    Early treatment with Lactobacillus delbrueckii strain induces rise in intestinal T cells and granulocytes and modulates immune related genes of larval Dicentrarchus labrax (L.)

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    Lactobacillus delbrueckii ssp. delbrueckii (AS13B), isolated from the gut of adult Dicentrarchus labrax, was administered live to developing sea bass using rotifers and Artemia as live carriers. Immune-related gene transcripts were quantified in post-larvae at day 70 post-hatch (ph) and histology, electron microscopy and immunocytochemistry of the intestinal tissue were performed at day 74 ph. Since the probiotic was orally administered the studies were focused on intestinal immunity. In treated fish gut integrity was unaffected, while the density of T-cells and acidophilic granulocytes in the intestinal mucosa was significantly higher than in controls. Probiotic-induced increases in intestinal T-cells and total body TcR-beta transcripts are first reported in fish. Significantly lower IL-1beta transcripts and a trend towards lower IL-10, Cox-2 and TGF-beta transcription were found in the treated group. Evidence is provided that early feeding with probiotic-supplemented diet stimulated the larval gut immune system and lowered transcription of key pro-inflammatory genes.L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com

    Mutable collagenous tissue: A concept generator for biomimetic materials and devices

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    Echinoderms (starfish, sea-urchins and their close relations) possess a unique type of collagenous tissue that is innervated by the motor nervous system and whose mechanical properties, such as tensile strength and elastic stiffness, can be altered in a time frame of seconds. Intensive research on echinoderm ‘mutable collagenous tissue’ (MCT) began over 50 years ago, and over 20 years ago, MCT first inspired a biomimetic design. MCT, and sea-cucumber dermis in particular, is now a major source of ideas for the development of new mechanically adaptable materials and devices with applications in diverse areas including biomedical science, chemical engineering and robotics. In this review, after an up-to-date account of present knowledge of the structural, physiological and molecular adaptations of MCT and the mechanisms responsible for its variable tensile properties, we focus on MCT as a concept generator surveying biomimetic systems inspired by MCT biology, showing that these include both bio-derived developments (same function, analogous operating principles) and technology-derived developments (same function, different operating principles), and suggest a strategy for the further exploitation of this promising biological resource

    Management of severe head injury with brain exposure in three loggerhead sea turtles Caretta caretta

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    The loggerhead Caretta caretta is the most common sea turtle in the Mediterranean. Currently, sea turtles are considered endangered, mainly due to the impact of human activities. Among traumatic lesions, those involving the skull, if complicated by brain exposure, are often life-threatening. In these cases, death could be the outcome of direct trauma of the cerebral tissue or of secondary meningoencephalitis. This uncontrolled study aims to evaluate the use of a plantderived dressing (1 Primary Wound Dressing®) in 3 sea turtles with severe lesions of the skull exposing the brain. Following surgical curettage, the treatment protocol involved exclusive use of the plant-derived dressing applied on the wound surface as the primary dressing, daily for the first month and then every other day until the end of treatment. The wound and peri-wound skin were covered with a simple secondary dressing without any active compound (non-woven gauze with petroleum jelly). Data presented herein show an excellent healing process in all 3 cases and no side effects due to contact of the medication with the cerebral tissue

    Neurodevelopmental disorders and development of project of life in a lifespan perspective: between habilitation and quality of life

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    AbstractFor some years, the term “project of life” has become widely used in the field of neurodevelopmentaldisorders, and, at the same time, it has begun to make its way in many socialand health planning documents. However, beyond its relatively widespread use, this termdoes not yet possess an adequate and shared frame of the main underlying decision-makingprocesses. In particular, there is a need to identify the crucial questions for orientingthe choice of goals within the adolescent transition, which represents the complex hingebetween childhood and adulthood. Moreover, adulthood, which is often completely devoidof culturally and socially shared references, is still critical precisely because of thelack of future direction prompts usually represented by the stages of development. In thiscase, the themes of quality of life functioning as a guiding compass appear pertinent andmuch more relevant. The present contribution is, therefore, an attempt to present, in aunitary manner, the decision-making processes and questions at the basis of a constructof “project of life” shared within the scientific and associative communities

    Fundamental aspects of arm repair phase in two echinoderm models

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    Regeneration is a post-embryonic developmental process that ensures complete morphological and functional restoration of lost body parts. The repair phase is a key step for the effectiveness of the subsequent regenerative process: in vertebrates, efficient re-epithelialisation, rapid inflammatory/immune response and post-injury tissue remodelling are fundamental aspects for the success of this phase, their impairment leading to an inhibition or total prevention of regeneration. Among deuterostomes, echinoderms display a unique combination of striking regenerative abilities and diversity of useful experimental models, although still largely unexplored. Therefore, the brittle star Amphiura filiformis and the starfish Echinaster sepositus were here used to comparatively investigate the main repair phase events after injury as well as the presence and expression of immune system and extracellular matrix (i.e. collagen) molecules using both microscopy and molecular tools. Our results showed that emergency reaction and re-epithelialisation are similar in both echinoderm models, being faster and more effective than in mammals. Moreover, in comparison to the latter, both echinoderms showed delayed and less abundant collagen deposition at the wound site (absence of fibrosis). The gene expression patterns of molecules related to the immune response, such as Ese-fib-like (starfishes) and Afi-ficolin (brittle stars), were described for the first time during echinoderm regeneration providing promising starting points to investigate the immune system role in these regeneration models. Overall, the similarities in repair events and timing within the echinoderms and the differences with what has been reported in mammals suggest that effective repair processes in echinoderms play an important role for their subsequent ability to regenerate. Targeted molecular and functional analyses will shed light on the evolution of these abilities in the deuterostomian lineage
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