1,918 research outputs found
A post-tsunami assessment of coastal living resources of Langkawi Archipelago, Peninsular Malaysia
Rapid and detailed post-tsunami surveys carried out in the Langkawi archipelago in January 2005 showed that the coral reefs dOld_ID not suffer any significant structural damage. Nevertheless, there were signs of recent sediment resuspension at the sites studied. The diversity and abundance of coral reef fishes and invertebrates were low. However, this was not attributed to the tsunami effect but rather to the present environmental conditions. The extent of damage at the villages of Kubang Badak and Kuala Teriang may indicate that intact coastal ecosystems such as mangroves have the potential to protect lives and property during natural disasters
Structural and magnetic study of a dilute magnetic semiconductor: Fe doped CeO2 nanoparticles
This paper reports the effect of Fe doping on the structure and room
temperature ferromagnetism of CeO2 nanoparticles. X-ray diffraction and
selective area electron diffraction measurement reflects that Ce1-xFexO2 (x =
0.0 - 0.07) nanoparticles exhibit single phase nature with cubic structure and
none of the sample showed the presence of any secondary phase. The mean
particle size calculated by using a transmission electron microscopy
measurement was found to increase with increase in Fe content. DC magnetization
measurements performed at room temperature indicates that all the samples
exhibit ferromagnetism. The saturation magnetic moment has been found to
increase with an increase in the Fe content.Comment: 16 Pages, 5 figure, 1 Table, Accepted in JN
Comparison of toxicity between ethanedinitrile (EDN) and methyl bromide (MB) to five species of stored product insects
Dynamics of Alpha-Helix Formation in the CSAW Model
We study the folding dynamics of polyalanine (Ala), a protein fragment
with 20 residues whose native state is a single alpha helix. We use the CSAW
model (conditioned self-avoiding walk), which treats the protein molecule as a
chain in Brownian motion, with interactions that include hydrophobic forces and
internal hydrogen bonding. We find that large scale structures form before
small scale structures, and obtain the relevant relaxation times. We find that
helix nucleation occurs at two separate points on the protein chain. The
evolution of small and large scale structures involve different mechanisms.
While the former can be describe by rate equations governing the growth of
helical content, the latter is akin to the relaxation of an elastic solid.Comment: 18 pages, 10 figure
Evaluation of synergistic effect between ethyl formate and phosphine for control of three species Aphids in perishable commodity
Methyl bromide (MB) as a fumigant for Quarantine and Pre-shipment (QPS) could offer eradication of target pests within shorter fumigation period and without phytotoxicity. Therefore, unlike MB alternatives for soil fumigation, there is no ideally MB alternative fumigant for QPS purpose, particularly for perishable commodities. It is critically important that within shorter fumigation time requires killing all target insect pests and without effect of quality and deliver treated fruit and vegetables to the final consumer. Aphids are pests frequently found in imported and exported fruit and vegetables. Aphids was known as quarantine pest hard to control when conduct short period fumigation with phosphine (PH3) and low dose of ethyl formate (EF). Ethyl formate can lead to highly sorption and phytotoxic damage of some perishable commodities such as strawberries and cut flowers, especially at lower temperature (< 8°C). Here, we reported that synergistic effect between ethyl formate and phosphine at lower dosages and temperature. The mixture of ethyl formate and phosphine had synergistic effect to control adult and nymph stages of tested cotton aphid (Aphis gossypii), green peach aphid (Myzus persicae) and turnip aphid (Lipaphis erysimi). When 0.5 mg/L of PH3 combined with different levels of EF at 5 and 20°C for 2 hours fumigation, there was significantly difference in terms of LCT50% and LCT90% values in comparison with EF or PH3 alone. This new technology could be meet QPS requirement that is shorter exposure time and less damage of perishable commodities
Room temperature ferromagnetism in chemically synthesized ZnO rods
We report structural and magnetic properties of pure ZnO rods using X-ray
diffraction (XRD), magnetization hysteresis (M-H) loop and near edge x-ray fine
structure spectroscopy (NEXAFS) study at O K edge. Sample of ZnO was prepared
by co-precipitation method. XRD and selective area electron diffraction
measurements infer that ZnO rods exhibit a single phase polycrystalline nature
with wurtzite lattice. Field emission transmission electron microscopy, field
emission scanning electron microscopy micrographs infers that ZnO have rod type
microstructures with dimension 200 nm in diameter and 550 nm in length. M-H
loop studies performed at room temperature display room temperature
ferromagnetism in ZnO rods. NEXAFS study reflects absence of the oxygen
vacancies in pure ZnO rods.Comment: 8 Pages, 3 Figure
GMRF Estimation under Topological and Spectral Constraints
International audienceWe investigate the problem of Gaussian Markov random field selection under a non-analytic constraint: the estimated models must be compatible with a fast inference algorithm, namely the Gaussian belief propagation algorithm. To address this question, we introduce the *-IPS framework, based on iterative proportional scaling, which incrementally selects candidate links in a greedy manner. Besides its intrinsic sparsity-inducing ability, this algorithm is flexible enough to incorporate various spectral constraints, like e.g. walk summability, and topological constraints, like short loops avoidance. Experimental tests on various datasets, including traffic data from San Francisco Bay Area, indicate that this approach can deliver, with reasonable computational cost, a broad range of efficient inference models, which are not accessible through penalization with traditional sparsity-inducing norms
Kinetic Study on Heavy Metal Divalent Ions Removal using Zirconium-Based Magnetic Sorbent
In this research, zirconium-based magnetic sorbent synthesised by chemical co-precipitation method is explored as a potential sorbent for removal of divalent metal ions from aqueous solution. The interaction characteristics between the ions and the sorbent were elucidated by instrumental analyses such as Fourier Transform InfraRed (FT-IR) Spectroscopy, Scanning Electron Microscopy (SEM), and Brunauer, Emmett, and Teller (BET) surface area analyser. Results show that the sorption rate was increased with an increase in contact time and initial metal ion concentration. Moreover, a two-stage kinetics behaviour was observed, and all the batch experiments achieved an equilibrium state within 4 hours. The evaluation of the adsorption behaviour of heavy metal divalent ions onto the magnetic sorbent was explained using two kinetic models, and it was mostly found to follow the postulate of the pseudo-second-order kinetic model. The validity of kinetic models applied in this study is also evaluated by using a normalised standard deviation
Quantum corrections to the mass of the supersymmetric vortex
We calculate quantum corrections to the mass of the vortex in N=2
supersymmetric abelian Higgs model in (2+1) dimensions. We put the system in a
box and apply the zeta function regularization. The boundary conditions
inevitably violate a part of the supersymmetries. Remaining supersymmetry is
however enough to ensure isospectrality of relevant operators in bosonic and
fermionic sectors. A non-zero correction to the mass of the vortex comes from
finite renormalization of couplings.Comment: Latex, 18 pp; v2 reference added; v3 minor change
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Isotope Effects in Complex Scattering Lengths for He Collisions With Molecular Hydrogen
We examine the effect of theoretically varying the collision-system reduced mass in collisions of He with vibrationally excited molecular hydrogen and observe zero-energy resonances for select atomic “hydrogen” masses less than 1 u or a “helium” mass of 1.95 u. Complex scattering lengths, state-to-state vibrational quenching cross sections, and a low-energy elastic scattering resonance are all studied as a function of collision-system reduced mass. Experimental observations of these phenomena in the cold and ultracold regimes for collisions of He and He with H, HD, HT, and DT should be feasible in the near future.Astronom
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