We analyze the transport of light in the bulk and at the edge of photonic Lieb lattices, whose unique feature is the existence of a flat band representing stationary states in the middle of the band ...structure that can form localized bulk states. We find that transport in bulk Lieb lattices is significantly affected by the particular excitation site within the unit cell, due to overlap with the flat band states. Additionally, we demonstrate the existence of new edge states in anisotropic Lieb lattices. These states arise due to a virtual defect at the lattice edges and are not described by the standard tight-binding model.
Within all physical disciplines, it is accepted that wave transport is predetermined by the existence of disorder. In this vein, it is known that ballistic transport is possible only when a structure ...is ordered, and that disorder is crucial for diffusion or (Anderson-)localization to occur. As this commonly accepted picture is based on the very foundations of quantum mechanics where Hermiticity of the Hamiltonian is naturally assumed, the question arises whether these concepts of transport hold true within the more general context of non-Hermitian systems. Here we demonstrate theoretically and experimentally that in ordered time-independent -symmetric systems, which are symmetric under space-time reflection, wave transport can undergo a sudden change from ballistic to diffusive after a specific point in time. This transition as well as the diffusive transport in general is impossible in Hermitian systems in the absence of disorder. In contrast, we find that this transition depends only on the degree of dissipation.
The Large Array Survey Telescope—Science Goals Ben-Ami, S.; Ofek, E. O.; Polishook, D. ...
Publications of the Astronomical Society of the Pacific,
08/2023, Letnik:
135, Številka:
1050
Journal Article
The superior olivary nucleus (SON) is the primary source of inhibition in the avian auditory brainstem. While much is known about the role of inhibition at the SON's target nuclei, little is known ...about how the SON itself processes auditory information or how inhibition modulates these properties. Additionally, the synaptic physiology of inhibitory inputs within the SON has not been described. We investigated these questions using in vivo and in vitro electrophysiological techniques in combination with immunohistochemistry in the chicken, an organism for which the auditory brainstem has otherwise been well characterized. We provide a thorough characterization of monaural response properties in the SON and the influence of inhibitory input in shaping these features. We found that the SON contains a heterogeneous mixture of response patterns to acoustic stimulation and that in most neurons these responses are modulated by both GABAergic and glycinergic inhibitory inputs. Interestingly, many SON neurons tuned to low frequencies have robust phase-locking capability and the precision of this phase locking is enhanced by inhibitory inputs. On the synaptic level, we found that evoked and spontaneous inhibitory postsynaptic currents (IPSCs) within the SON are also mediated by both GABAergic and glycinergic inhibition in all neurons tested. Analysis of spontaneous IPSCs suggests that most SON cells receive a mixture of both purely GABAergic terminals, as well as terminals from which GABA and glycine are coreleased. Evidence for glycinergic signaling within the SON is a novel result that has important implications for understanding inhibitory function in the auditory brainstem.
With the utilization of DC systems increasing, and constant emphasis for worker safety as a top priority for all companies, arc flash feasibility for DC systems is a growing concern. This article ...details the feasibility of DC arc flash events with experimental scouting tests for a 130 VDC system. Sensitivity studies are experimentally performed on the impact of bus gap distance and bolted fault current level on incident energy. Test results are analyzed and conclusions drawn on the results, in particular incident energies. Details of the tests performed including the setup, procedure, and system parameters are also provided. Theoretical methods of determining incident energy for the testing conditions are also explored. Specifically, these are Doan's and NFPA 70E's maximum power models, and Stokes and Oppenlander's and Paukert's arc resistance models. A comparative analysis of the test results to industry standard, NFPA 70E, and software analysis methods using ETAP, an industry leading software used for arc flash studies, is performed.
Summary
Objective To evaluate a new method of deriving the reproductive number for vector‐borne diseases from the early epidemic curves for vector‐borne diseases with incubations in the vectors and ...in the hosts.
Method We applied the model to several dengue epidemics in different climatic regions of Brazil: Brasilia, Belém, Fortaleza, Boa Vista.
Results The new method leads to higher estimates of the reproductive number than previous models.
Conclusion At present, Aedes aegypti densities, the meeting of more compatible strains of viruses and mosquitoes, may lead to re‐emergence of urban yellow fever epidemics.
Objectifs Evaluer une nouvelle méthode de détermination du nombre reproductif pour les maladies transmises par des vecteurs à partir des courbes épidémiques précoces des maladies transmises par des vecteurs avec incubation chez le vecteur et chez l'hôte.
Méthode Nous avons appliqué le modèle à plusieurs épidémies de dengue dans différentes régions climatiques du Brésil: Brazilia, Belém, Fortazela, Boa Vista.
Résultats La nouvelle méthode permet des estimations plus élevées du nombre reproductif par rapport aux méthodes antérieures.
Conclusion A l'heure actuelle, les densités de Ae. Aegypti, la presence de plusieurs souches compatibles du virus et des moustiques peut mener à une re‐émergence d’épidèmies de fièvre jaune urbaine.
Objetivo Evaluar un nuevo método para obtener el número reproductivo para enfermedades transmitidas por vectores, con incubaciones en los vectores y en los hospederos, a partir de las curvas epidémicas tempranas.
Método Aplicamos el modelo a varias epidemias de dengue en diferentes regiones climáticas del Brasil: Brasilia, Belén, Fortaleza, Boa Vista.
Resultados El nuevo método conlleva a estimaciones más altas del número reproductivo que modelos anteriores.
Conclusión Con las densidades actuales de Ae. aegypti, el encuentro de cepas de virus y mosquitos más compatibles puede conllevar a la re‐emergencia de epidemias urbanas de fiebre amarilla.
The intensity of interspecific territorial defense should be based upon the degree of competitive overlap. We tested this relationship in two territorial Caribbean damselfish (dusky, Stegastes ...adustus, and longfin, S. diencaeous) with intruders being the bluehead wrasse (Thalassoma bifascatus) and the slippery dick wrasse (Halichoeres bivittatus). Based on food habits, the slippery dick and the bluehead wrasse should have the same degree of competitive overlap to the two damselfish species. We also predicted that the larger slippery dick wrasse intruder would receive more aggression than the smaller bluehead wrasse intruder. Neither damselfish species distinguished between the two wrasses suggesting that they were ecologically equivalent. We also tested size differences within both species of wrasse and found that size had no influence on the aggression in the dusky damselfish. The longfin also did not show a size preference for the bluehead but did prefer to attack the larger slippery dick wrasse. In spite of the similarities between the dusky and the longfin damselfish and the similar food habits of the bluehead and the slippery dick wrasse, our results suggest that using intensity of interspecific territorial defense alone may not be an adequate measure of competitive overlap.
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