Growth and habitat requirements of juvenile flatfish at nursery grounds in Galway Bay, Ireland

Coastal zones are essential nursery habitats for most juvenile flatfish species. Fish stocks are highly dependent on suitable coastal habitat features for obtaining food, shelter, and rapid growth during the vulnerable juvenile life stage. Understanding the ecological habitat requirements for juvenile flatfish is important in determining their abundance and to reliably predict potential impacts of changing coastal ecosystems on fish stocks. The present study assesses the influence of habitat characteristics on the growth and abundance of juvenile dab and plaice in four nursery areas within Galway Bay, Ireland. Field sampling was carried out in summer 2008 using a beam trawl for the collection of flatfish and a van Veen grab for the collection of sediment. The distribution and abundance of the juvenile flatfish was assessed in relation to biotic (predator–prey abundance) and abiotic (sediment size, organic content, depth, temperature, and salinity) habitat features. The condition and growth of flatfish were compared in different nursery areas and a model of habitat requirements for juvenile plaice and dab was developed. Significant variability of the measured characteristics was observed between nursery areas and high-quality nursery areas for dab and plaice were identified. These results will act as the basis for mapping of essential flatfish habitats in Galway Bay

Toxic Mixtures in Time—The Sequence Makes the Poison

“The dose makes the poison”. This principle assumes that once a chemical is cleared out of the organism (toxicokinetic recovery), it no longer has any effect. However, it overlooks the other process of re-establishing homeostasis, toxicodynamic recovery, which can be fast or slow depending on the chemical. Therefore, when organisms are exposed to two toxicants in sequence, the toxicity can differ if their order is reversed. We test this hypothesis with the freshwater crustacean Gammarus pulex and four toxicants that act on different targets (diazinon, propiconazole, 4,6-dinitro-o-cresol, 4-nitrobenzyl chloride). We found clearly different toxicity when the exposure order of two toxicants was reversed, while maintaining the same dose. Slow toxicodynamic recovery caused carry-over toxicity in subsequent exposures, thereby resulting in a sequence effect–but only when toxicodynamic recovery was slow relative to the interval between exposures. This suggests that carry-over toxicity is a useful proxy for organism fitness and that risk assessment methods should be revised as they currently could underestimate risk. We provide the first evidence that carry-over toxicity occurs among chemicals acting on different targets and when exposure is several days apart. It is therefore not only the dose that makes the poison but also the exposure sequence

Logarithmic behavior of degradation dynamics in metal--oxide semiconductor devices

In this paper the authors describe a theoretical simple statistical modelling of relaxation process in metal-oxide semiconductor devices that governs its degradation. Basically, starting from an initial state where a given number of traps are occupied, the dynamics of the relaxation process is measured calculating the density of occupied traps and its fluctuations (second moment) as function of time. Our theoretical results show a universal logarithmic law for the density of occupied traps $\bar{} \sim \phi (T,E_{F}) (A+B \ln t)$, i.e., the degradation is logarithmic and its amplitude depends on the temperature and Fermi Level of device. Our approach reduces the work to the averages determined by simple binomial sums that are corroborated by our Monte Carlo simulations and by experimental results from literature, which bear in mind enlightening elucidations about the physics of degradation of semiconductor devices of our modern life

Marine Mammals and Megafauna in Irish Waters - Behaviour, Distribution and Habitat Use- WP3 Biotelemetry of Marine Megafauna in Irish Waters

*Work Package Leader: Simon Berrow, Irish Whale and Dolphin Group *Project Partners: Galway Mayo Institute of Technology *Author(s): Berrow, S.D. and O’Connor, I. *Project Duration: 01 February 2008 to 31August 2011Biotelemetry is the transmission of information from biological organisms through the atmosphere by radio waves. It encompasses a wide range of devices that can record environmental variables while attached to an animal, such as depth, salinity and temperature, while permitting the recording and transmitting of the position of an animal, commonly referred to as tracking. A review of biotelemetry, with reference to relevant species in Ireland, is presented. Although a number of marine species have been tagged and tracked in Ireland, these studies were generally of short duration or involved small numbers of individuals. However, these studies have shown that tracking marine megafauna in Ireland can be successful and that there is great potential for biotelemetry.This project (Grant-Aid Agreement No. PBA/ME/07/005(02)) was carried out under the Sea Change Strategy with the support of the Marine Institute and the Marine Research Sub-Programme of the National Development Plan 2007–2013, and through funding from the Department of Arts, Heritage and the Gaeltacht.Funder: Marine Institut

Lifetime Measurement of the 6s Level of Rubidium

We present a lifetime measurements of the 6s level of rubidium. We use a time-correlated single-photon counting technique on two different samples of rubidium atoms. A vapor cell with variable rubidium density and a sample of atoms confined and cooled in a magneto-optical trap. The 5P_{1/2} level serves as the resonant intermediate step for the two step excitation to the 6s level. We detect the decay of the 6s level through the cascade fluorescence of the 5P_{3/2} level at 780 nm. The two samples have different systematic effects, but we obtain consistent results that averaged give a lifetime of 45.57 +- 0.17 ns.Comment: 10 pages, 9 figure

Scaling Laws and Effective Dimension in Lattice SU(2) Yang-Mills Theory with a Compactified Extra Dimension

Monte Carlo simulations are performed in a five-dimensional lattice SU(2) Yang-Mills theory with a compactified extra dimension, and scaling laws are studied. Our simulations indicate that as the compactification radius $R$ decreases, the confining phase spreads more and more to the weak coupling regime, and the effective dimension of the theory changes gradually from five to four. Our simulations also indicate that the limit $a_4 to 0$ with $R/a_4$ kept fixed exists both in the confining and deconfining phases if $R/a_4$ is small enough, where $a_4$ is the lattice spacing in the four-dimensional direction. We argue that the color degrees of freedom in QCD are confined only for $R < R_{\rm max}$, where a rough estimate shows that $1/R_{\rm max}$ lies in the TeV range. Comments on deconstructing extra dimensions are given.Comment: 15 pages, TeX, 5 figure

Significance of Xenobiotic Metabolism for Bioaccumulation Kinetics of Organic Chemicals in Gammarus pulex

Bioaccumulation and biotransformation are key toxicokinetic processes that modify toxicity of chemicals and sensitivity of organisms. Bioaccumulation kinetics vary greatly among organisms and chemicals; thus, we investigated the influence of biotransformation kinetics on bioaccumulation in a model aquatic invertebrate using fifteen C-14-labeled organic xenobiotics from diverse chemical classes and physicochemical properties (1,2,3-trichlorobenzene, imidacloprid, 4,6-dinitro-o-cresol, ethylacrylate, malathion, chlorpyrifos, aldicarb, carbofuran, carbaryl, 2,4-dichlorophenol, 2,4,5-trichlorophenol, pentachlorophenol, 4-nitrobenzyl-chloride, 2,4-dichloroaniline, and sea-nine (4,5-dichloro-2-octyl-3-isothiazolone)). We detected and identified metabolites using HPLC with UV and radio-detection as well as high resolution mass spectrometry (LTQ-Orbitrap). Kinetics of uptake, biotransformation, and elimination of parent compounds and metabolites were modeled with a first-order one-compartment model. Bioaccumulation factors were calculated for parent compounds and metabolite enrichment factors for metabolites. Out of 19 detected metabolites, we identified seven by standards or accurate mass measurements and two via pathway analysis and analogies to other compounds. 1,2,3-Trichlorobenzene, imidacloprid, and 4,6-dinitro-o-cresol were not biotransformed. Dietary uptake contributed little to overall uptake. Differentiation between parent and metabolites increased accuracy of bioaccumulation parameters compared to total C-14 measurements. Biotransformation dominated toxicokinetics and strongly affected internal concentrations of parent compounds and metabolites. Many metabolites reached higher internal concentrations than their parents, characterized by large metabolite enrichment factors

Electrical Properties of High-k Oxide in Pd/Al2O3/InGaAs Stack

The paper presents the results of capacitance-voltage (C-V) characterization of metal-oxidesemiconductor (MOS) structure, namely Pd/Al2O3/ In0.53Ga0.47As/InP. It is shown that MOS structure under study exhibit both electron and hole trapping with permanent and temporary charge trapping contributions. The interfacial transition layer between the high-k oxide and InGaAs has the greatest influence on this charge trapping phenomenon. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3504

Integrated plasmonic circuitry on a vertical-cavity surface-emitting semiconductor laser platform

Integrated plasmonic sources and detectors are imperative in the practical development of plasmonic circuitry for bio- and chemical sensing, nanoscale optical information processing, as well as transducers for high-density optical data storage. Here we show that vertical-cavity surface-emitting lasers (VCSELs) can be employed as an on-chip, electrically pumped source or detector of plasmonic signals, when operated in forward or reverse bias, respectively. To this end, we experimentally demonstrate surface plasmon polariton excitation, waveguiding, frequency conversion and detection on a VCSEL-based plasmonic platform. The coupling efficiency of the VCSEL emission to waveguided surface plasmon polariton modes has been optimized using asymmetric plasmonic nanostructures. The plasmonic VCSEL platform validated here is a viable solution for practical realizations of plasmonic functionalities for various applications, such as those requiring sub-wavelength field confinement, refractive index sensitivity or optical near-field transduction with electrically driven sources, thus enabling the realization of on-chip optical communication and lab-on-a-chip devices