1,304 research outputs found
The effects of mate switching tacticon reproductive performance of the severum cichlid, Heros severus
This study investigated the effects of mate switching on the reproductive performance of the severum cichlid, Heros severus, by advancing the egg and larval production in hatcheries. Two reproductive tactic treatments of “monogamous pair” and “mate switching” were used for evaluating 4 reproductive traits of egg production, hatching rate, spawning intervals, and starvation tolerance of the larvae in 6 spawning activities. The number of eggs was not significantly different between the two reproductive tactic treatments in the 6 spawning activities, but the spawning intervals, hatching rate, and survival activity index were all significantly different. Daily average egg and larval production in the mate switching treatment were estimated to be 87.3 eggs and 43.1 larvae per pair of fish, respectively, which was 2.89 times and 1.99 times of those in the monogamous pair treatment, who produced about 30.2 eggs and 21.6 larvae per pair. Our results clearly showed that the reproductive tactic of mate switching is a suitable method for increasing the egg and larval production rate of the severum cichlid
Chalcogenide glasses for photonics device applications
Chalcogenides are compounds formed predominately from one or more of the chalcogen elements; sulphur, selenium and tellurium. Although first studied over fifty years ago, interest in chalcogenide glasses has, over the past few years, increased significantly as glasses, crystals and alloys find new life in a wide range of photonic devices. This chapter begins with an overview of chalcogenide glass compositions, their purification, synthesis and fabrication. Focussing on more novel gallium lanthanum sulphide based chalcogenides, as well as reviewing more established materials such as arsenic trisulphide based glasses we then explore the purification and synthesis of these materials, along with their basic optical and thermal properties. Next the fabrication of these versatile glasses into a variety of forms; including thin films, microspheres and optical fibers is explained. This chapter ends with an overview of representative applications of these exciting optoelectronic materials
Regge description of two pseudoscalar meson production in antiproton-proton annihilation
A Regge-inspired model is used to discuss the hard exclusive two-body
hadronic reactions (pbar p ----> pi+ pi-, pi0 pi0, K+ K-, Kbar0 K0) for the
FAIR facility project at GSI with the Panda detector. The comparison between
the differential cross sections predictions and the available data is shown to
determine the values of the few parameters of the model.Comment: 9 pages, 13 figure
First-Principles Studies of Hydrogenated Si(111)--77
The relaxed geometries and electronic properties of the hydrogenated phases
of the Si(111)-77 surface are studied using first-principles molecular
dynamics. A monohydride phase, with one H per dangling bond adsorbed on the
bare surface is found to be energetically favorable. Another phase where 43
hydrogens saturate the dangling bonds created by the removal of the adatoms
from the clean surface is found to be nearly equivalent energetically.
Experimental STM and differential reflectance characteristics of the
hydrogenated surfaces agree well with the calculated features.Comment: REVTEX manuscript with 3 postscript figures, all included in uu file.
Also available at http://www.phy.ohiou.edu/~ulloa/ulloa.htm
Nonlinear Parabolic Equations arising in Mathematical Finance
This survey paper is focused on qualitative and numerical analyses of fully
nonlinear partial differential equations of parabolic type arising in financial
mathematics. The main purpose is to review various non-linear extensions of the
classical Black-Scholes theory for pricing financial instruments, as well as
models of stochastic dynamic portfolio optimization leading to the
Hamilton-Jacobi-Bellman (HJB) equation. After suitable transformations, both
problems can be represented by solutions to nonlinear parabolic equations.
Qualitative analysis will be focused on issues concerning the existence and
uniqueness of solutions. In the numerical part we discuss a stable
finite-volume and finite difference schemes for solving fully nonlinear
parabolic equations.Comment: arXiv admin note: substantial text overlap with arXiv:1603.0387
Comparison of dimensional accuracies of stereolithography and powder binder printing
This paper presents a comparative experimental investigation of the dimensional accuracies of two widely used rapid prototyping (RP) processes: stereolithography (SLA) and powder binder printing (PBP). Four replicates of a purpose-designed component using each RP process were fabricated, and the measurements of the internal and external features of all surfaces were performed using a general-purpose coordinate measurement machine. The results showed that in both cases, the main cause of dimensional variations was the volumetric change inherent in the process. The precision of SLA was far better than that of PBP. The dimensional accuracy of SLA was better in the z direction, whereas PBP produced better dimensional accuracy in the x–y plane. In both RP processes, the height error consisted of two components: constant error and cumulative error. The constant error component was equal to the datum surface error. SLA yielded an average datum surface error that was 68 % higher than in PBP. The height error of SLA improved with the increase in nominal height, whereas it deteriorated in PBP
Experimental study of the anaerobic urban wastewater treatment in a submerged hollow-fibre membrane bioreactor at pilot scale
The aim of this study was to assess the effect of several operational variables on both biological and separation process performance in a submerged anaerobic membrane bioreactor pilot plant that treats urban wastewater. The pilot plant is equipped with two industrial hollow-fibre ultrafiltration membrane modules (PURON¿ Koch Membrane Systems, 30m 2 of filtration surface each). It was operated under mesophilic conditions (at 33°C), 70days of SRT, and variable HRT ranging from 20 to 6h. The effects of the influent COD/SO 4-S ratio (ranging from 2 to 12) and the MLTS concentration (ranging from 6 to 22gL -1) were also analysed. The main performance results were about 87% of COD removal, effluent VFA below 20mgL -1 and biogas methane concentrations over 55% v/v. Methane yield was strongly affected by the influent COD/SO 4-S ratio. No irreversible fouling problems were detected, even for MLTS concentrations above 22gL -1. © 2011 Elsevier Ltd.This research work has been supported by the Spanish Research Foundation (CICYT Projects CTM2008-06809-C02-01 and CTM2008-06809-C02-02), which is gratefully acknowledged.Giménez García, JB.; Robles Martínez, Á.; Carretero Martin, L.; Durán Pinzón, F.; Ruano García, MV.; Gatti, MN.; Ribes Bertomeu, J.... (2011). Experimental study of the anaerobic urban wastewater treatment in a submerged hollow-fibre membrane bioreactor at pilot scale. Bioresource Technology. 102(19):8799-8806. doi:10.1016/j.biortech.2011.07.014S879988061021
Helminth infection reactivates latent γ-herpesvirus via cytokine competition at a viral promoter
Mammals are coinfected by multiple pathogens that interact through unknown mechanisms. We found that helminth infection, characterized by the induction of the cytokine interleukin-4 (IL-4) and the activation of the transcription factor Stat6, reactivated murine γ-herpesvirus infection in vivo. IL-4 promoted viral replication and blocked the antiviral effects of interferon-γ (IFNγ) by inducing Stat6 binding to the promoter for an important viral transcriptional transactivator. IL-4 also reactivated human Kaposi's sarcoma-associated herpesvirus from latency in cultured cells. Exogenous IL-4 plus blockade of IFNγ reactivated latent murine γ-herpesvirus infection in vivo, suggesting a "two-signal" model for viral reactivation. Thus, chronic herpesvirus infection, a component of the mammalian virome, is regulated by the counterpoised actions of multiple cytokines on viral promoters that have evolved to sense host immune status
Interlaminar fracture micro-mechanisms in toughened carbon fibre reinforced plastics investigated via synchrotron radiation computed tomography and laminography
A self-interaction corrected pseudopotential scheme for magnetic and strongly-correlated systems
Local-spin-density functional calculations may be affected by severe errors
when applied to the study of magnetic and strongly-correlated materials. Some
of these faults can be traced back to the presence of the spurious
self-interaction in the density functional. Since the application of a fully
self-consistent self-interaction correction is highly demanding even for
moderately large systems, we pursue a strategy of approximating the
self-interaction corrected potential with a non-local, pseudopotential-like
projector, first generated within the isolated atom and then updated during the
self-consistent cycle in the crystal. This scheme, whose implementation is
totally uncomplicated and particularly suited for the pseudopotental formalism,
dramatically improves the LSDA results for a variety of compounds with a
minimal increase of computing cost.Comment: 18 pages, 14 figure
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