Prediction of radiated electromagnetic emissions from PCB traces based on Green dyadics

Because it costs to solve ElectroMagnetic Compatibility (EMC) problems late in the development process, new methods have to predict radiated electromagnetic emissions at the design stage. In the case of complex printed Circuit Boards (PCBs) containing embedded microstrips and a large number of nets, a tradeoff between accuracy and simulation time must be found for this evaluation. In this paper the basic algorithm used within a new emissions predictive analysis tool: ElectroMagnetic Interferences Radiated (EMIR) is presented. It is able to take accurately into account the actual cross section between the metal plane and the air for each PCB trace. It is compared to theoretical formulas for validation. The effects of superstrate (cover) on a dipole radiation are describe

Faber-Krahn and Lieb-type inequalities for the composite membrane problem

The classical Faber-Krahn inequality states that, among all domains with given measure, the ball has the smallest first Dirichlet eigenvalue of the Laplacian. Another inequality related to the first eigenvalue of the Laplacian has been proved by Lieb in 1983 and it relates the first Dirichlet eigenvalues of the Laplacian of two different domains with the first Dirichlet eigenvalue of the intersection of translations of them. In this paper we prove the analogue of Faber-Krahn and Lieb inequalities for the composite membrane problem

G-convergence of elliptic and parabolic operators depending on vector fields

We consider sequences of elliptic and parabolic operators in divergence form and depending on a family of vector fields. We show compactness results with respect to G-convergence, or H-convergence, by means of the compensated compactness theory, in a setting in which the existence of affine functions is not always guaranteed, due to the nature of the family of vector fields

Epidemic dynamics of respiratory syncytial virus in current and future climates.

A key question for infectious disease dynamics is the impact of the climate on future burden. Here, we evaluate the climate drivers of respiratory syncytial virus (RSV), an important determinant of disease in young children. We combine a dataset of county-level observations from the US with state-level observations from Mexico, spanning much of the global range of climatological conditions. Using a combination of nonlinear epidemic models with statistical techniques, we find consistent patterns of climate drivers at a continental scale explaining latitudinal differences in the dynamics and timing of local epidemics. Strikingly, estimated effects of precipitation and humidity on transmission mirror prior results for influenza. We couple our model with projections for future climate, to show that temperature-driven increases to humidity may lead to a northward shift in the dynamic patterns observed and that the likelihood of severe outbreaks of RSV hinges on projections for extreme rainfall

Machine learning approach to the background reduction in singly charged cosmic-ray isotope measurements with AMS-02

Studying the isotopic composition of single-charge cosmic rays (CRs) provides essential data to investigate the CR propagation processes in our Galaxy. While current measurements are rare above 4 GeV/nucleon, the Alpha Magnetic Spectrometer (AMS-02) is able to measure the isotopic fluxes up to 10 GeV/n by combining the momentum measured by the silicon tracker with the precise measurements of the velocity provided by its Ring Imaging Cherenkov Detector (RICH). The correct measurement of the particles’ velocity is essential for identifying isotopes through their mass. This is particularly challenging for single-charge particles due to the low number of photons they produce in their Cherenkov rings, which makes the reconstruction easily disrupted by noise. Hence, identifying the sources and cleaning the sample from the background is essential for ensuring the quality of the rings. In this paper, we propose a novel approach to track the events whose mass is misidentified due to interactions inside the AMS-02 detector. Based on the actual location of these interactions, we propose a novel strategy to mitigate the background effectively and with high efficiency, which includes using cut-based selection criteria and a multivariate estimator based on the signals detected by the RICH.</p

Iterative-Bayesian unfolding of isotopic cosmic-ray fluxes measured by AMS-02

The measurement of the isotopic composition of cosmic rays (CRs) provides essential insights the understanding of the origin and propagation of these particles, namely the CR source spectra, the propagation processes and the galactic halo size. The Alpha Magnetic Spectrometer (AMS-02), a CR detector operating aboard the International Space Station since May 2011, has the capability of performing these measurements due to its precise determination of the velocity provided by its Time of Flight (TOF) and Ring Imaging Cherenkov (RICH) detector. The correct interpretation of the data requires the measurements to be deconvoluted from the instrumental effects. The unique design of AMS-02, with more than one subdetector being used to measure the same flux, requires a novel approach to unfold the measured fluxes. In this work, we describe an iterative-Bayesian unfolding method applied in the context of isotopic flux measurements in AMS-02. The accuracy of the method is assessed using a simulated flux based on previous measurements and a full detector response function. We introduce a non-parametric regularization method for the detector response functions, as well as a single, smooth prior flux covering the full range of measurements from both detectors, TOF and RICH. In addition, the estimation of the errors and a discussion about the performance of the method are also shown, demonstrating that the method is fast and reliable, allowing for the recovery of the true fluxes in the full energy range.Comment: Submitted to NIM

A parametric approach for the identification of single-charged isotopes with AMS-02

Measurements of the isotopic composition of single-charged cosmic rays provide important insights in the propagation processes. However, the isotopic identification is challenging due to the one hundred times greater abundance of protons when compared to deuterons, the only stable isotope of hydrogen. Taking advantage of the precise measurements of the velocity and momentum in the Alpha Magnetic Spectrometer (AMS-02), a particle physics detector operating aboard the International Space Station since May 2011, we describe a parametric template fit method, which takes into account systematic uncertainties such as the fragmentation of particles inside AMS-02 and eventual differences between data and simulation through the use of nuisance parameters. With this method we are also able to assess the AMS-02 performance in terms of mass resolution, showing that it is able to separate the isotopes of hydrogen up to 10 GeV/n.Comment: Accepted for publication in Nuclear Instruments and Methods in Physics Research Section

From Assessing to Conserving biodiversity. Conceptual and Practical Challenges

This open access book features essays written by philosophers, biologists, ecologists and conservation scientists facing the current biodiversity crisis. Despite increasing communication, accelerating policy and management responses, and notwithstanding improving ecosystem assessment and endangered species knowledge, conserving biodiversity continues to be more a concern than an accomplished task. Why is it so? The overexploitation of natural resources by our species is a frequently recognised factor, while the short-term economic interests of governments and stakeholders typically clash with the burdens that implementing conservation actions imply. But this is not the whole story. This book develops a different perspective on the problem by exploring the conceptual challenges and practical defiance posed by conserving biodiversity, namely: on the one hand, the difficulties in defining what biodiversity is and characterizing that “thing” to which the word ‘biodiversity’ refers to; on the other hand, the reasons why assessing biodiversity and putting in place effective conservation actions is arduous. ; Features essays that are explicitly critical of the species approach to biodiversity Presents bio-philosophical perspectives on the interaction between biodiversity’s units, levels, and scales Serves as an interdisciplinary contribution to the emergent field of biodiversity studie