Radiation Pattern Reconstruction from the Near-Field Amplitude Measurement on Two Planes Using PSO

The paper presents a new approach to the radiation pattern reconstruction from near-field amplitude only measurement over a two planar scanning surfaces. This new method for antenna pattern reconstruction is based on the global optimization PSO (Particle Swarm Optimization). The paper presents appropriate phaseless measurement requirements and phase retrieval algorithm together with a brief description of the particle swarm optimization method. In order to examine the methodologies developed in this paper, phaseless measurement results for two different antennas are presented and compared to results obtained by a complex measurement (amplitude and phase)

Dipole Array Excited by Slots in its Coaxial Feeder

A technical analysis of the coaxial dipole-array excited by periodically distributed slots in common coaxial feeder is presented. The lossy transmission-line theory is applied for determination of the current on all parts of the system. Calculated results support some properties of the system, especially the radiation pattern and the input impedance

Multireflector Antennas - Cascaded Structures with Frequency Selective Surfaces

The problem of increasing the gain of directional multiband antennas is solved in the paper. A single-fed multiband (wideband) planar dipole is combined with cascaded (sandwiched) reflectors made of frequency selective surfaces. Each of those reflectors is placed in a quarter-wavelength distance from the dipole at the frequency of operation. The impedance matching is particularly achieved by active element properties, and impedance symmetrization. Further transformation is made by a planar circuit, placed on the active element plane. The antenna gain is set by the reflector elements amount (reflector plane dimensions). The antenna structure enables its setting into arrays with in-phase feeding

Historia de las relaciones científicas entre Cuba y el American Museum of Natural History (AMNH) : 160 años de colección y colaboración (1857-2017)

132 pages : illustrations (some color), color map ; 28 cm.Spanish and English on facing pages. Includes bibliographical references (pages 123-126)

Heritage and cultural healing: Iraq in a post-Daesh era

Against the backdrop of the destruction of Iraqi heritage over the past quarter of a century, this article critically reviews key aspects of the current state of Iraq’s cultural heritage, including damage to heritage buildings caused by Daesh in Iraq’s second largest city, Mosul. We bring together Iraqi and non-Iraqi expertise in heritage, archaeology, and human rights law to frame our approach, building on the movement to link cultural diversity, heritage, and cultural rights. We emphasise the need for planning to enhance protection of Iraq’s heritage, in particular through preparation of inventories, the provision of resources for heritage education in schools and the development of Iraq’s museum sector. Iraq’s presence on the UNESCO World Heritage Lists needs to be enhanced and the issues of illicit site looting and traffic in looted antiquities must be addressed within international contexts. Iraq’s future accession as State Party to the 1999 Second Protocol to the 1954 Hague Convention is a priority in achieving these goals. The paper stresses the need for co-creation of heritage knowledge and a gender-sensitive human rights approach for the future of Iraq’s globally significant cultural heritage

W(h)ither Fossils? Studying Morphological Character Evolution in the Age of Molecular Sequences

A major challenge in the post-genomics era will be to integrate molecular sequence data from extant organisms with morphological data from fossil and extant taxa into a single, coherent picture of phylogenetic relationships; only then will these phylogenetic hypotheses be effectively applied to the study of morphological character evolution. At least two analytical approaches to solving this problem have been utilized: (1) simultaneous analysis of molecular sequence and morphological data with fossil taxa included as terminals in the analysis, and (2) the molecular scaffold approach, in which morphological data are analyzed over a molecular backbone (with constraints that force extant taxa into positions suggested by sequence data). The perceived obstacles to including fossil taxa directly in simultaneous analyses of morphological and molecular sequence data with extant taxa include: (1) that fossil taxa are missing the molecular sequence portion of the character data; (2) that morphological characters might be misleading due to convergence; and (3) character weighting, specifically how and whether to weight characters in the morphological partition relative to characters in the molecular sequence data partition. The molecular scaffold has been put forward as a potential solution to at least some of these problems. Using examples of simultaneous analyses from the literature, as well as new analyses of previously published morphological and molecular sequence data matrices for extant and fossil Chiroptera (bats), we argue that the simultaneous analysis approach is superior to the molecular scaffold approach, specifically addressing the problems to which the molecular scaffold has been suggested as a solution. Finally, the application of phylogenetic hypotheses including fossil taxa (whatever their derivation) to the study of morphological character evolution is discussed, with special emphasis on scenarios in which fossil taxa are likely to be most enlightening: (1) in determining the sequence of character evolution; (2) in determining the timing of character evolution; and (3) in making inferences about the presence or absence of characteristics in fossil taxa that may not be directly observable in the fossil record. Published By: Missouri Botanical Garde