99 research outputs found

    On the Precarious Path of Reverse Neuro-Engineering

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    In this perspective we provide an example for the limits of reverse engineering in neuroscience. We demonstrate that application of reverse engineering to the study of the design principle of a functional neuro-system with a known mechanism, may result in a perfectly valid but wrong induction of the system's design principle. If in the very simple setup we bring here (static environment, primitive task and practically unlimited access to every piece of relevant information), it is difficult to induce a design principle, what are our chances of exposing biological design principles when more realistic conditions are examined? Implications to the way we do Biology are discussed

    Training and validation of a novel non-invasive imaging system for ruling out malignancy in canine subcutaneous and cutaneous masses using machine learning in 664 masses

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    ObjectiveTo train and validate the use of a novel artificial intelligence-based thermal imaging system as a screening tool to rule out malignancy in cutaneous and subcutaneous masses in dogs.AnimalsTraining study: 147 client-owned dogs with 233 masses. Validation Study: 299 client-owned dogs with 525 masses. Cytology was non-diagnostic in 94 masses, resulting in 431 masses from 248 dogs with diagnostic samples.ProceduresThe prospective studies were conducted between June 2020 and July 2022. During the scan, each mass and its adjacent healthy tissue was heated by a high-power Light-Emitting Diode. The tissue temperature was recorded by the device and consequently analyzed using a supervised machine learning algorithm to determine whether the mass required further investigation. The first study was performed to collect data to train the algorithm. The second study validated the algorithm, as the real-time device predictions were compared to the cytology and/or biopsy results.ResultsThe results for the validation study were that the device correctly classified 45 out of 53 malignant masses and 253 out of 378 benign masses (sensitivity = 85% and specificity = 67%). The negative predictive value of the system (i.e., percent of benign masses identified as benign) was 97%.Clinical relevanceThe results demonstrate that this novel system could be used as a decision-support tool at the point of care, enabling clinicians to differentiate between benign lesions and those requiring further diagnostics

    enhancing the circular economy with nature based solutions in the built urban environment green building materials systems and sites

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    Abstract The objective of this review paper is to survey the state of the art on nature-based solutions (NBS) in the built environment, which can contribute to a circular economy (CE) and counter the negative impacts of urbanization through the provision of ecosystem services. NBS are discussed here at three different levels: (i) green building materials, including biocomposites with plant-based aggregates; (ii) green building systems, employed for the greening of buildings by incorporating vegetation in their envelope; and (iii) green building sites, emphasizing the value of vegetated open spaces and water-sensitive urban design. After introducing the central concepts of NBS and CE as they are manifested in the built environment, we examine the impacts of urban development and the historical use of materials, systems and sites which can offer solutions to these problems. In the central section of the paper we present a series of case studies illustrating the development and implementation of such solutions in recent years. Finally, in a brief critical analysis we look at the ecosystem services and disservices provided by NBS in the built environment, and examine the policy instruments which can be leveraged to promote them in the most effective manner – facilitating the future transition to fully circular cities

    The Early Ultraviolet Light-Curves of Type II Supernovae and the Radii of Their Progenitor Stars

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    We present a sample of 34 normal SNe II detected with the Zwicky Transient Facility, with multi-band UV light-curves starting at t4t \leq 4 days after explosion, as well as X-ray detections and upper limits. We characterize the early UV-optical colors and provide prescriptions for empirical host-extinction corrections. We show that the t>2t > 2\,days UV-optical colors and the blackbody evolution of the sample are consistent with the predictions of spherical phase shock-cooling (SC), independently of the presence of `flash ionization" features. We present a framework for fitting SC models which can reproduce the parameters of a set of multi-group simulations without a significant bias up to 20% in radius and velocity. Observations of about half of the SNe II in the sample are well-fit by models with breakout radii <1014<10^{14}\,cm. The other half are typically more luminous, with observations from day 1 onward that are better fit by a model with a large >1014>10^{14}\,cm breakout radius. However, these fits predict an early rise during the first day that is too slow. We suggest these large-breakout events are explosions of stars with an inflated envelope or a confined CSM with a steep density profile, at which breakout occurs. Using the X-ray data, we derive constraints on the extended (1015\sim10^{15} cm) CSM density independent of spectral modeling, and find most SNe II progenitors lose <104Myr1<10^{-4} M_{\odot}\, \rm yr^{-1} a few years before explosion. This provides independent evidence the CSM around many SNe II progenitors is confined. We show that the overall observed breakout radius distribution is skewed to higher radii due to a luminosity bias. We argue that the 6622+11%66^{+11}_{-22}\% of red supergiants (RSG) explode as SNe II with breakout radii consistent with the observed distribution of field RSG, with a tail extending to large radii, likely due to the presence of CSM.Comment: Submitted to ApJ. Comments are welcome at [email protected] or [email protected]

    Blind competition on the numerical simulation of continuous shallow steel‐fiber reinforced concrete beams failing in bending

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    This article describes the second blind simulation competition (BSC) organized by the fib WG 2.4.1, which aims to assess the predictive performance of models based on the finite element method (FEM) for the analysis and design of fiber reinforced concrete (FRC) structures. Slabs supported on columns or piles have becoming competitive applications for FRC due to the technical and economic benefits may be obtained by combining properly the fiber reinforcement mechanisms to those provided by conventional reinforcement placed, as a strip, in the alignment of columns/piles. Therefore, a representative zone of this structural system, namely a hybrid fiber reinforced concrete (R/FRC) shallow beam, is chosen in this BSC to show the potentialities of FRC in these types of applications, as well as to assess the predictive performance of FEM-based computational models on the design verification at serviceability and at ultimate limit state conditions (SLS and ULS, respectively). Two statically indeterminateshallow beams of two equal spans were tested up to their failure, by recording the applied loads, the strains in the conventional reinforcements and in the FRC of the critical zones of the structure. By using digital image correlation, the average crack width at the level of the flexural reinforcements was recorded. The participants had to predict these results by receiving information about the mechanical properties of the materials, the geometry of the prototypes and their loading and support conditions. In this article, the rules and the results of this 2nd BSC competition are presented, and the data obtained experimentally is thoroughly analyzed.PID2021-125553NB-I00; PTDC/ECI-EST/6300/202

    The prevalence and influence of circumstellar material around hydrogen-rich supernova progenitors

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    Narrow transient emission lines (flash-ionization features) in early supernova (SN) spectra trace the presence of circumstellar material (CSM) around the massive progenitor stars of core-collapse SNe. The lines disappear within days after the SN explosion, suggesting that this material is spatially confined, and originates from enhanced mass loss shortly (months to a few years) prior to explosion. We performed a systematic survey of H-rich (Type II) SNe discovered within less than two days from explosion during the first phase of the Zwicky Transient Facility (ZTF) survey (2018-2020), finding thirty events for which a first spectrum was obtained within <2< 2 days from explosion. The measured fraction of events showing flash ionisation features (>36%>36\% at 95%95\% confidence level) confirms that elevated mass loss in massive stars prior to SN explosion is common. We find that SNe II showing flash ionisation features are not significantly brighter, nor bluer, nor more slowly rising than those without. This implies that CSM interaction does not contribute significantly to their early continuum emission, and that the CSM is likely optically thin. We measured the persistence duration of flash ionisation emission and find that most SNe show flash features for 5\approx 5 days. Rarer events, with persistence timescales >10>10 days, are brighter and rise longer, suggesting these may be intermediate between regular SNe II and strongly-interacting SNe IIn

    The Involvement of IL-17A in the Murine Response to Sub-Lethal Inhalational Infection with Francisella tularensis

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    Background: Francisella tularensis is an intercellular bacterium often causing fatal disease when inhaled. Previous reports have underlined the role of cell-mediated immunity and IFNc in the host response to Francisella tularensis infection. Methodology/Principal Findings: Here we provide evidence for the involvement of IL-17A in host defense to inhalational tularemia, using a mouse model of intranasal infection with the Live Vaccine Strain (LVS). We demonstrate the kinetics of IL-17A production in lavage fluids of infected lungs and identify the IL-17A-producing lymphocytes as pulmonary cd and Th17 cells. The peak of IL-17A production appears early during sub-lethal infection, it precedes the peak of immune activation and the nadir of the disease, and then subsides subsequently. Exogenous airway administration of IL-17A or of IL-23 had a limited yet consistent effect of delaying the onset of death from a lethal dose of LVS, implying that IL-17A may be involved in restraining the infection. The protective role for IL-17A was directly demonstrated by in vivo neutralization of IL-17A. Administration of anti IL-17A antibodies concomitantly to a sub-lethal airway infection with 0.16LD50 resulted in a fatal disease. Conclusion: In summary, these data characterize the involvement and underline the protective key role of the IL-17A axis in the lungs from inhalational tularemia
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