137 research outputs found
Parallel Implementation of the Discrete Green's Function Formulation of the FDTD Method on a Multicore Central Processing Unit
Parallel implementation of the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method was developed on a multicore central processing unit. DGF-FDTD avoids computations of the electromagnetic field in free-space cells and does not require domain termination by absorbing boundary conditions. Computed DGF-FDTD solutions are compatible with the FDTD grid enabling the perfect hybridization of FDTD with the use of time-domain integral equation methods. The developed implementation can be applied to simulations of antenna characteristics. For the sake of example, arrays of Yagi-Uda antennas were simulated with the use of parallel DGF-FDTD. The efficiency of parallel computations was investigated as a function of the number of current elements in the FDTD grid. Although the developed method does not apply the fast Fourier transform for convolution computations, advantages stemming from the application of DGF-FDTD instead of FDTD can be demonstrated for one-dimensional wire antennas when simulation results are post-processed by the near-to-far-field transformation
Teleportation of geometric structures in 3D
Simplest quantum teleportation algorithms can be represented in geometric
terms in spaces of dimensions 3 (for real state-vectors) and 4 (for complex
state-vectors). The geometric representation is based on geometric-algebra
coding, a geometric alternative to the tensor-product coding typical of quantum
mechanics. We discuss all the elementary ingredients of the geometric version
of the algorithm: Geometric analogs of states and controlled Pauli gates. Fully
geometric presentation is possible if one employs a nonstandard representation
of directed magnitudes, formulated in terms of colors defined via stereographic
projection of a color wheel, and not by means of directed volumes.Comment: typos corrected, one plot remove
Threat-sensitive anti-predator defence in precocial wader, the northern lapwing Vanellus vanellus
Birds exhibit various forms of anti-predator behaviours to avoid reproductive failure, with mobbingâobservation, approach and usually harassment of a predatorâbeing one of the most commonly observed. Here, we investigate patterns of temporal variation in the mobbing response exhibited by a precocial species, the northern lapwing (Vanellus vanellus). We test whether brood age and self-reliance, or the perceived risk posed by various predators, affect mobbing response of lapwings. We quantified aggressive interactions between lapwings and their natural avian predators and used generalized additive models to test how timing and predator species identity are related to the mobbing response of lapwings. Lapwings diversified mobbing response within the breeding season and depending on predator species. Raven Corvus corax, hooded crow Corvus cornix and harriers evoked the strongest response, while common buzzard Buteo buteo, white stork Ciconia ciconia, black-headed gull Chroicocephalus ridibundus and rook Corvus frugilegus were less frequently attacked. Lapwings increased their mobbing response against raven, common buzzard, white stork and rook throughout the breeding season, while defence against hooded crow, harriers and black-headed gull did not exhibit clear temporal patterns. Mobbing behaviour of lapwings apparently constitutes a flexible anti-predator strategy. The anti-predator response depends on predator species, which may suggest that lapwings distinguish between predator types and match mobbing response to the perceived hazard at different stages of the breeding cycle. We conclude that a single species may exhibit various patterns of temporal variation in anti-predator defence, which may correspond with various hypotheses derived from parental investment theory
Review of low-cost sensors for indoor air quality: Features and applications
Humans spend the majority of their time indoors, where they are potentially exposed to hazardous pollutants. Within this context, over the past few years, there has been an upsurge of low-cost sensors (LCS) for the measurement of indoor air pollutants, motivated both by recent technological advances and by increased awareness of indoor air quality (IAQ) and its potential negative health impacts. Although not meeting the performance requirements for reference regulatory-equivalent monitoring indoors, LCS can provide informative measurements, offering an opportunity for high-resolution monitoring, emission source identification, exposure mitigation and managing IAQ and energy efficiency, among others. This article discusses the strengths and limitations that LCS offer for applications in the field of IAQ monitoring; it provides an overview of existing sensor technologies and gives recommendations for different indoor applications, considering their performance in the complex indoor environment and discussing future trends
Phase-space formulation of quantum mechanics and quantum state reconstruction for physical systems with Lie-group symmetries
We present a detailed discussion of a general theory of phase-space
distributions, introduced recently by the authors [J. Phys. A {\bf 31}, L9
(1998)]. This theory provides a unified phase-space formulation of quantum
mechanics for physical systems possessing Lie-group symmetries. The concept of
generalized coherent states and the method of harmonic analysis are used to
construct explicitly a family of phase-space functions which are postulated to
satisfy the Stratonovich-Weyl correspondence with a generalized traciality
condition. The symbol calculus for the phase-space functions is given by means
of the generalized twisted product. The phase-space formalism is used to study
the problem of the reconstruction of quantum states. In particular, we consider
the reconstruction method based on measurements of displaced projectors, which
comprises a number of recently proposed quantum-optical schemes and is also
related to the standard methods of signal processing. A general group-theoretic
description of this method is developed using the technique of harmonic
expansions on the phase space.Comment: REVTeX, 18 pages, no figure
Variation of Basal EROD Activities in Ten Passerine Bird Species â Relationships with Diet and Migration Status
Inter-specific differences in animal defence mechanisms against toxic substances are currently poorly understood. The ethoxyresorufin-O-deethylase (EROD) enzyme plays an important role in defence against toxic chemicals in a wide variety of animals, and it is an important biomarker for environmental contamination. We compared basal hepatic EROD activity levels among ten passerine species to see if there is inter-specific variation in enzyme activity, especially in relation to their diet and migration status. Migratory insectivores showed higher EROD activity compared to granivores. We hypothesize that the variable invertebrate diet of migratory insectivores contains a wider range of natural toxins than the narrower diet of granivores. This may have affected the evolution of mixed function oxidases (MFO) system and enzyme activities. We further tested whether metabolic rates or relative liver size were associated with the variation in detoxification capacity. We found no association between EROD activity and relative (per mass unit) basal metabolic rate (BMR). Instead, EROD activity and relative liver mass (% of body mass) correlated positively, suggesting that a proportionally large liver also functions efficiently. Our results suggest that granivores and non-migratory birds may be more vulnerable to environmental contaminants than insectivores and migratory birds. The diet and migration status, however, are phylogenetically strongly connected to each other, and their roles cannot be fully separated in our analysis with only ten passerine species
Second Warmia and Masuria Road Forum
Druga edycja WarmiĹsko-Mazurskiego Forum Drogowego w paĹşdzierniku 2015 r. zgromadziĹa przeszĹo 120 przedstawicieli administracji drogowej, firm projektowych i wykonawczych. Przed obradami w Lidzbarku WarmiĹskim uczestnicy konferencji byli w Olsztynie goĹÄmi otwarcia wystawy fotograficznej Warmia i Mazury â zielone i bezpieczne drogi. Podsumowanie efektĂłw Regionalnego Programu Operacyjnego 2007â2013.The second edition of Warmia and Masuria Road Forum held in October 2015 brought together over 120 representatives from road authorities, design firms and contractors. Before the session in Lidzbark WarmiĹski, conference participants attended the opening of the photographic exhibition "Warmia and Masuria" - Green and Safe Roads" held in Olsztyn. Summary of the effects of the Regional Operational Programme 2007-2013
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