Assessment of Noise Reduction Concepts for Leading-Edge Slat Noise

The leading-edge slat of a high-lift airfoil can be a significant noise contributor during aircraft landing. This paper summarizes the effects of several passive noise reduction devices on the 30P30N high-lift airfoil. Experiments are conducted on a two-dimensional multi-element high-lift airfoil with leading-edge slat extensions, gap filler, and cove filler in an anechoic wind tunnel to evaluate the effect of passive flow control on the acoustics generated by the unsteady flow field. Slat geometry modifications associated with the treatments alter the flow field in the region that dominates the generation of the acoustic field. Three angles of attack (a(k) = 8, 10, and 15.5) and three different Reynolds numbers (Re(c) = 1.2e6, 1.5e6, and 1.71e6) are selected as the test conditions. Steady surface pressure measurements are conducted to assess the effect of the treatments on the lift and drag. Unsteady surface pressure measurements along with the far-field acoustic array measurements are performed to evaluate the changes in near- and far-field pressure fluctuations, respectively. Delay and Sum (DAS) beamforming method is applied to locate the noise sources on the model and provide integrated spectra. Implementation difficulties with the gap filler led to structural integration deficiencies that prevented a fair assessment of this technology. Among the other passive devices, the cove filler s the most effective noise reduction, along with a negligible change in the aerodynamic metrics

Certifiably Correct Range-Aided SLAM

We present the first algorithm to efficiently compute certifiably optimal solutions to range-aided simultaneous localization and mapping (RA-SLAM) problems. Robotic navigation systems increasingly incorporate point-to-point ranging sensors, leading to state estimation problems in the form of RA-SLAM. However, the RA-SLAM problem is significantly more difficult to solve than traditional pose-graph SLAM: ranging sensor models introduce non-convexity and single range measurements do not uniquely determine the transform between the involved sensors. As a result, RA-SLAM inference is sensitive to initial estimates yet lacks reliable initialization techniques. Our approach, certifiably correct RA-SLAM (CORA), leverages a novel quadratically constrained quadratic programming (QCQP) formulation of RA-SLAM to relax the RA-SLAM problem to a semidefinite program (SDP). CORA solves the SDP efficiently using the Riemannian Staircase methodology; the SDP solution provides both (i) a lower bound on the RA-SLAM problem's optimal value, and (ii) an approximate solution of the RA-SLAM problem, which can be subsequently refined using local optimization. CORA applies to problems with arbitrary pose-pose, pose-landmark, and ranging measurements and, due to using convex relaxation, is insensitive to initialization. We evaluate CORA on several real-world problems. In contrast to state-of-the-art approaches, CORA is able to obtain high-quality solutions on all problems despite being initialized with random values. Additionally, we study the tightness of the SDP relaxation with respect to important problem parameters: the number of (i) robots, (ii) landmarks, and (iii) range measurements. These experiments demonstrate that the SDP relaxation is often tight and reveal relationships between graph rigidity and the tightness of the SDP relaxation.Comment: 17 pages, 9 figures, submitted to T-R

Identification of the major proteins of an immune modulating fraction from adult Fasciola hepatica released by Nonidet P40

Fasciola hepatica NP-40 released antigens (FhTeg) exhibit potent Th1 immunosuppressive properties in vitro and in vivo. However, the protein composition of this active fraction, responsible for Th1 immune modulatory activity, has yet to be resolved. Therefore, FhTeg, a Nonidet P-40 extract, was subjected to a proteomic analysis in order to identify individual protein components. This was performed using an in house F. hepatica EST database following 2D electrophoresis combined with de novo sequencing based mass spectrometry. The identified proteins, a mixture of excretory/secretory and membrane-associated proteins, are associated with stress response and chaperoning, energy metabolism and cytoskeletal components. The immune modulatory properties of these identified protein(s) is discussed and HSP70 from F. hepatica is highlighted as a potential host immune modulator for future study

What Caused the Significant Increase in Atlantic Ocean Heat Content Since the mid-20th Century?

As the upper layer of the world ocean warms gradually during the 20th century, the inter-ocean heat transport from the Indian to Atlantic basin should be enhanced, and the Atlantic Ocean should therefore gain extra heat due to the increased upper ocean temperature of the inflow via the Agulhas leakage. Consistent with this hypothesis, instrumental records indicate that the Atlantic Ocean has warmed substantially more than any other ocean basin since the mid-20th century. A surface-forced global ocean-ice coupled model is used to test this hypothesis and to find that the observed warming trend of the Atlantic Ocean since the 1950s is largely due to an increase in the inter-ocean heat transport from the Indian Ocean. Further analysis reveals that the increased inter-ocean heat transport is not only caused by the increased upper ocean temperature of the inflow but also, and more strongly, by the increased Agulhas Current leakage, which is augmented by the strengthening of the wind stress curl over the South Atlantic and Indian subtropical gyre

Tolerance induction in memory CD4 T cells requires two rounds of antigen-specific activation

Autoimmune diseases are driven by immune cells that recognize self-tissues. A major goal for treatment strategies for autoimmune diseases is to turn off or tolerize self-reactive immune cells such as CD4 T cells that coordinate tissue damage in many autoimmune diseases. Autoimmune diseases are often diagnosed many years following their onset. The self-reactive CD4 T cells that must be tolerized, therefore, are previously activated or memory CD4 T cells. Little is known about whether tolerance can be induced in memory CD4 T cells. This paper demonstrates that memory CD4 T cells survive initial exposure to tolerance-inducing signals but that a second activation signal leads to cell death. This study has important implications for immunotherapeutic strategies for autoimmune diseases

Explicit modelling of resources for multi-agent microservices using the cartago framework

The 19th International Conference on Autonomous Agents and Multiagent Systems (AAMS 2020), Auckland, New Zealand, 9-13 May 2020This paper describes the first agent programming language agnostic implementation of the Multi-Agent MicroServices (MAMS) model - an approach to integrating agents within microservices-based architectures where agents expose aspects of their state as virtual resources, realised as CArtAgO artifacts, that are externally accessible through REpresentational State Transfer (REST).Science Foundation Irelan

MAMS: Multi-Agent MicroServices

The 2019 World Wide Web Conference (WWW'19), San Francisco, United States of America, 13-17 May 2019This paper explores the intersection between microservices and Multi-Agent Systems (MAS), introducing the notion of a new approach to building MAS known as Multi-Agent MicroServices (MAMS). Our approach is illustrated through a worked example of a Vickrey Auction implemented as a microservice.Science Foundation IrelandOrigin Enterprises Pl

Klein-Gordon Solutions on Non-Globally Hyperbolic Standard Static Spacetimes

We construct a class of solutions to the Cauchy problem of the Klein-Gordon equation on any standard static spacetime. Specifically, we have constructed solutions to the Cauchy problem based on any self-adjoint extension (satisfying a technical condition: "acceptability") of (some variant of) the Laplace-Beltrami operator defined on test functions in an $L^2$-space of the static hypersurface. The proof of the existence of this construction completes and extends work originally done by Wald. Further results include the uniqueness of these solutions, their support properties, the construction of the space of solutions and the energy and symplectic form on this space, an analysis of certain symmetries on the space of solutions and of various examples of this method, including the construction of a non-bounded below acceptable self-adjoint extension generating the dynamics

Ethical considerations in natural history film production and the need for industry-wide best practice

Natural history documentary films can be a powerful tool for wildlife conservation, providing an accessible means to increase public knowledge of the natural world. There has been an increasing focus in documentary films on the threats to biodiversity in recent years that has positively aided conservation efforts. However, potential ethical and welfare implications of natural history film making are often overlooked. Here, we consider the design and impact of the narratives used and the filming methods employed in natural history film making and their potential implications for conservation. Although these programmes are often lauded for their cinematography, filming techniques and practices should satisfy high ethical standards and should be evaluated to assess disturbance caused to wildlife and any associated negative behavioural and physiological impacts. This evaluation should include the direct impact of the filming, as well as considering the risk of viewers replicating human-wildlife encounters they see on film. Trends towards the use of highly dramatized storytelling, anthropomorphism and the inclusion of inaccurate information should also be addressed. Although some production companies have filming guidelines in place, this is not standard industry practice. Natural history films are an important means of educating and enthusing people about nature and its conservation; however, it is vital that films are made responsibly. To facilitate this discussion, we propose recommendations, including standardised industry-wide guidelines, codes of conduct and independent ethical reviews, for natural history film makers to mitigate and avoid negative impacts

CanStem111P trial: A Phase 3 Study of napabucasin (NAPA) plus nab-paclitaxel (nPTX) with gemcitabine (Gem) in adult patients with metastatic pancreatic adenocarcinoma (mPDAC) - Trial in progress

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