1,330 research outputs found

    Recursive Motion and Structure Estimation with Complete Error Characterization

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    We present an algorithm that perfom recursive estimation of ego-motion andambient structure from a stream of monocular Perspective images of a number of feature points. The algorithm is based on an Extended Kalman Filter (EKF) that integrates over time the instantaneous motion and structure measurements computed by a 2-perspective-views step. Key features of our filter are (I) global observability of the model, (2) complete on-line characterization of the uncertainty of the measurements provided by the two-views step. The filter is thus guaranteed to be well-behaved regardless of the particular motion undergone by the observel: Regions of motion space that do not allow recovery of structure (e.g. pure rotation) may be crossed while maintaining good estimates of structure and motion; whenever reliable measurements are available they are exploited. The algorithm works well for arbitrary motions with minimal smoothness assumptions and no ad hoc tuning. Simulations are presented that illustrate these characteristics

    Motion estimation via dynamic vision

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    Detection of a misaligned broken pipe by electromagnetic interaction

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    The study we are presenting concerns electromagnetic scattering of a plane wave due to the presence of a misaligned broken pipe buried in a half-space occupied by cement and by asphalt/ground, for civil-engineering applications

    Evolutive emergence and divergence of an Ig regulatory node: An environmental sensor getting cues from the aryl hydrocarbon receptor?

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    One gene, the immunoglobulin heavy chain (IgH) gene, is responsible for the expression of all the different antibody isotypes. Transcriptional regulation of the IgH gene is complex and involves several regulatory elements including a large element at the 3’ end of the IgH gene locus (3’RR). Animal models have demonstrated an essential role of the 3’RR in the ability of B cells to express high affinity antibodies and to express different antibody classes. Additionally, environmental chemicals such as aryl hydrocarbon receptor (AhR) ligands modulate mouse 3’RR activity that mirrors the effects of these chemicals on antibody production and immunocompetence in mouse models. Although first discovered as a mediator of the toxicity induced by the high affinity ligand 2,3,7,8-tetracholordibenzo-p-dioxin (dioxin), understanding of the AhR has expanded to a physiological role in preserving homeostasis and maintaining immunocompetence. We posit that the AhR also plays a role in human antibody production and that the 3’RR is not only an IgH regulatory node but also an environmental sensor receiving signals through intrinsic and extrinsic pathways, including the AhR. This review will 1) highlight the emerging role of the AhR as a key transducer between environmental signals and altered immune function; 2) examine the current state of knowledge regarding IgH gene regulation and the role of the AhR in modulation of Ig production; 3) describe the evolution of the IgH gene that resulted in species and population differences; and 4) explore the evidence supporting the environmental sensing capacity of the 3’RR and the AhR as a transducer of these cues. This review will also underscore the need for studies focused on human models due to the premise that understanding genetic differences in the human population and the signaling pathways that converge at the 3’RR will provide valuable insight into individual sensitivities to environmental factors and antibody-mediated disease conditions, including emerging infections such as SARS-CoV-2

    Introduction to radar scattering application in remote sensing and diagnostics: Review

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    The manuscript reviews the current literature on scattering applications of RADAR (Radio Detecting And Ranging) in remote sensing and diagnostics. This paper gives prime features for a variety of RADAR applications ranging from forest and climate monitoring to weather forecast, sea status, planetary information, and mapping of natural disasters such as the ones caused by earthquakes. Both the fundamental parameters involved in scattering mechanisms of RADAR applications and the factors affecting RADAR performances are also discusse

    From rods to helices: evidence of a screw-like nematic phase

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    Evidence of a special chiral nematic phase is provided using numerical simulation and Onsager theory for systems of hard helical particles. This phase appears at the high density end of the nematic phase, when helices are well aligned, and is characterized by the C2_2 symmetry axes of the helices spiraling around the nematic director with periodicity equal to the particle pitch. This coupling between translational and rotational degrees of freedom allows a more efficient packing and hence an increase of translational entropy. Suitable order parameters and correlation functions are introduced to identify this screw-like phase, whose main features are then studied as a function of radius and pitch of the helical particles. Our study highlights the physical mechanism underlying a similar ordering observed in colloidal helical flagella [E. Barry et al. \textit{Phys. Rev. Lett.} \textbf{96}, 018305 (2006)] and raises the question of whether it could be observed in other helical particle systems, such as DNA, at sufficiently high densities.Comment: List of authors correcte

    Postharvest behaviour of minimally processed watercress

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    16-18Watercress (Nasturtium officinale R. Br.) is an aquatic plant of the Brassicaceae family and used as a leafy vegetable that grows in and around water. It is consumed raw or steamed and has a short shelf life of approximately seven days. The objective of this study was to evaluate the postharvest behaviour of watercress minimally processed and stored at optimal storage temperature vs. market temperature. Treatments were: shoots packed with plain film (PD961EZ, 31µm thickness) and stored in refrigerated chambers at 1 ± 0.5 oC and 8 ± 2 oC for 10 days. Overall visual quality, gas concentration inside the packages, chlorophyll, reducing sugar, ascorbic acid, oxalic acid and weight loss were evaluated. At the end of the storage period overall visual quality, gas concentration and reducing sugars were affected by storage time and temperature, whereas dehidro ascorbic, oxalic acid and weight loss were not

    Postharvest behaviour of minimally processed watercress

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    16-18Watercress (Nasturtium officinale R. Br.) is an aquatic plant of the Brassicaceae family and used as a leafy vegetable that grows in and around water. It is consumed raw or steamed and has a short shelf life of approximately seven days. The objective of this study was to evaluate the postharvest behaviour of watercress minimally processed and stored at optimal storage temperature vs. market temperature. Treatments were: shoots packed with plain film (PD961EZ, 31µm thickness) and stored in refrigerated chambers at 1 ± 0.5 oC and 8 ± 2 oC for 10 days. Overall visual quality, gas concentration inside the packages, chlorophyll, reducing sugar, ascorbic acid, oxalic acid and weight loss were evaluated. At the end of the storage period overall visual quality, gas concentration and reducing sugars were affected by storage time and temperature, whereas dehidro ascorbic, oxalic acid and weight loss were not

    Analysis of four new enterococcus faecalis phages and modeling of a hyaluronidase catalytic domain from saphexavirus

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    Background: Phage therapy (PT), as a method to treat bacterial infections, needs identification of bacteriophages targeting specific pathogenic host. Enterococcus faecalis, a Gram-positive coccus resident in the human gastrointestinal tract, may become pathogenic in hospitalized patients showing acquired resistance to vancomycin and thus representing a possible target for PT. Materials and Methods: We isolated four phages that infect E. faecalis and characterized them by host range screening, transmission electron microscopy, and genome sequencing. We also identified and three-dimensional modeled a new hyaluronidase enzyme. Results: The four phages belong to Siphoviridae family: three Efquatrovirus (namely vB_EfaS_TV51, vB_EfaS_TV54, and vB_EfaS_TV217) and one Saphexavirus (vB_EfaS_TV16). All of them are compatible with lytic cycle. vB_EfaS_TV16 moreover presents a gene encoding for a hyaluronidase enzyme. Conclusions: The identified phages show features suggesting their useful application in PT, particularly the Saphexavirus that may be of enhanced relevance in PT because of its potential biofilm-digestion capability
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