Search results for "SIP"

Extensive tailorability of sound absorption using acoustic metamaterials

2017

We present an experimental demonstration of sound absorption tailorability, using acoustic metamaterials made of resonant cavities that does not rely on any dissipative material. As confirmed by numerical calculation, we particularly show that using quarter-wave-like resonators made of deep subwavelength slits allows a high confinement of the acoustic energy of an incident wave. This leads to enhance the dissipation in the cavities and, consequently, generates strong sound absorption, even over a wide frequency band. We finally demonstrate experimentally the key role of the filling ratio in tailoring such an absorption, using a metamaterial constituted of space-coiled cavities embedded in a…

Excitons in few-layer hexagonal boron nitride: Davydov splitting and surface localization

2018

Hexagonal boron nitride (hBN) has been attracting great attention because of its strong excitonic effects. Taking into account few-layer systems, we investigate theoretically the effects of the number of layers on quasiparticle energies, absorption spectra, and excitonic states, placing particular focus on the Davydov splitting of the lowest bound excitons. We describe how the inter-layer interaction as well as the variation in electronic screening as a function of layer number $N$ affects the electronic and optical properties. Using both \textit{ab initio} simulations and a tight-binding model for an effective Hamiltonian describing the excitons, we characterize in detail the symmetry of t…

Statistical methods for adaptive river basin management and monitoring

2018

Decision-making at different phases of adaptive river basin management planning rely largely on the information that is gained through environmental monitoring. The aim of this thesis was to develop and test statistical assessment tools presumed to be particularly useful for evaluating existing monitoring designs, converting monitoring data into management information and quantifying uncertainties. River basin scale monitoring was performed using a wireless sensor network and a data quality control system and maintenance effort was assessed. National-scale, traditional monitoring data and linear mixed effect modelling were used to estimate the uncertainty in two status class metrics (total …

Study of locomotion response and development in zebrafish (Danio rerio) embryos and larvae exposed to enniatin A, enniatin B, and beauvericin.

2021

Mycotoxins are secondary metabolites produced by a variety of fungi that contaminate food and feed resources, and are capable of inducing a wide range of toxicity. Here, we studied the developmental and behavioral toxicity in zebrafish (Danio rerio) embryos and larvae exposed to three mycotoxins: beauvericin (BEA), Enniatin A (ENN A), and Ennitain B (ENN B). Zebrafish embryos were collected after fertilization, treated individually from 1 to 6 dpf with BEA at 8, 16, 32 and, 64 μM and for both enniatins at 3.12, 6.25, 12.5 and, 25 μM. Mixture of mycotoxins were assayed as follows: i) for BEA + ENN A and BEA + ENN B at [32 + 12.5] μM and [16 + 6.25] μM; ii) for ENN A + ENN B at [12.5 + 12.5] …

VoIP sistēmu arhitektūras un augstas noslodzes sistēmas realizācija

2021

Bakalaura darbā “VoIP sistēmu arhitektūras un augstas noslodzes sistēmas realizācija” tiek apskatītas VoIP izmantojamās tehnoloģijas – konkrēti - uz SIP protokola bāzētie VoIP telefonijas risinājumi. Darba ietvaros tiek aprakstītas arī SIP-protokola bāzētā telefonijā iesaistītās serveru un klientu puses komponentes, kā arī tiek analizētas risinājumu iespējamās arhitektūras - vienkāršas “biroja centrāles” viss-vienā arhitektūras, kā arī piedāvātas sarežģītas sakaru operatoru risinājuma līmeņa uz komponentēm bazētas arhitektūras, kas darbojas uz atvērtā koda risinājumu pamata. Bakalaura darba rezultātā realizēta un notestēta augstas noslodzes VoIP sistēma, kura kalpo kā prototips, kas ir gata…

Rickettsiae of the spotted fever group in dog fleas (Ctenocephalides spp.) in Western Sicily

1989

Fissiphalliidae, a new family of South American laniatorean harvestmen (Arachnida: Opiliones)

2009

Fissiphalliidae, a new family of the Opiliones suborder Laniatores, is described in the superfamily Gonyleptoidea, based on a new genus (Fissiphallius n. gen.) und 3 new species (F. sturmi n. sp., F. spinulatus n. sp., F. sympatricus n. sp.) from Colombia. Most emphasized are the male genitalic characters, unique in Opiliones: A honzontally split truncus which results in a long movable (glans) and an immovable finger (distal part of the truncus). Both hide the extremely long stylus with the seminal opening at its end. In an expanded state, the movable finger is bent dorsally by an erectile vesicle. It is shown that male genitalic characters in Opiliones display clear functional and construc…

New distributional data on <em>Haemogregarina stepanowi</em> (Apicomplexa) and <em>Placobdella costata</em> (Hirudinea) paras…

2021

The host-parasite system “Emys trinacris – Placobdella costata – Haemogregarina stepanowi” is known for Sicily, but scarce information is available to date about the distribution of the two parasites on the island. Therefore, an extensive sampling effort through visual census and collection and analysis of blood smears of the endemic Sicilian pond turtle E. trinacris was carried out in 46 water bodies scattered throughout mainland Sicily. Our findings revealed that the distribution of both parasites is limited to the Nebrodi area, where the infection of H. stepanowi has shown a high incidence on the local turtle populations. Our data suggest no correlation between the current distribution o…

Reservoir characteristics of Mainz pouch studied in animal model

1993

In a canine model of the Mainz pouch, intracavitary pressure and compliance were measured during instillation of isosmotic and hyperosmotic (900 mmol/kg water) solutions of saline. Wall properties of small- and large-bowel segments of the pouch were assessed individually by sonomicrometry. Intraluminal pressures increased more steeply during filling with hyperosmotic solution, resulting in reduced distensibility of small- and large-bowel segments. Additionally, instillation of the hyperosmotic solution resulted in increased amplitudes and frequency of intracavitary pressure waves. The results indicate that this was the result of a combination of intensified bowel contractions and an increas…

Coherent Amplification of the Short Optical Pulse in a Non-linear Birefringent Medium

2006

International audience; The propagation of the solitary waves in the resonant birefringent amplifier with linear losses is considered. The birefringent optical linear medium contains two-level atoms with the upper state degenerated over projection of angular moment. It is assumed that population of resonance levels of atoms is inverted. The steady state pulse of polarized radiation that is vectorial generalization of the known pi-pulse was analytically found. Numerical simulations demonstrate the formation dynamics solitary waves originated in birefringent amplifier.