Development, Characterization and Cross-species Transferability of Expressed Sequence Tag-simple Sequence Repeat (EST-SSR) Markers Derived from Kelampayan Tree Transcriptome

Neolamarckia cadamba (or locally known as kelampayan) is an important fast growing plantation tree species that confers various advantages for timber industry as a strategy for reducing the logging pressure on natural forests for wood production to an acceptable level. Hence, attempts were made to develop a set of EST-SSR markers for kelampayan trees based on the EST sequences of kelampayan (NcdbEST) and further assessed the polymorphisms and transferability of the markers to other species. In this study, 155 (2.34%) out of 6,622 EST sequences which contain 232 SSRs were mined from NcdbEST. Of these, 97 ESTs were assigned with putative functions and gene ontology terms. Eighteen EST-SSR markers were developed according to the criteria, and further characterized and validated by using 50 individuals of kelampayan from two selected mother trees. The markers exhibited a considerable high level of polymorphism in kelampayan trees with an average of 4.17 and 4.11 alleles per locus, and PIC values of 0.465 and 0.537, respectively for mother trees T1 and T2. Parentage assignment analysis suggests a high probability for kelampayan trees to be predominantly outcrossed. The transferability rate was ranging from 16.7-94.4% among the five cross-genera species of kelampayan. The present study is the first report of the development of EST-SSR markers in kelampayan. These markers will be valuable genomic resources that could pave the way for exploiting the genotype data for comparative genome mapping, association genetics, population genetics studies and molecular breeding of kelampayan and other indigenous tropical tree species in future

Nano Fe3O4-activated carbon composites for aqueous supercapacitors

In this study, a symmetric supercapacitor has been fabricated by adopting the nanostructured iron oxide (Fe3O4)-activated carbon (AC) composite as the core electrode materials. The composite electrodes were prepared via a facile mechanical mixing process and PTFE polymeric solution has been used as the electrode material binder. Structural analysis of the nanocomposite electrodes were characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The electrochemical performances of the prepared supercapacitor were studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 1.0 M Na2SO3 and 1.0 M Na2SO4 aqueous solutions, respectively. The experimental results showed that the highest specific capacitance of 43 F/g is achieved with a fairly low Fe3O4 nanomaterials loading (4 wt. %) in 1 M Na2SO3. It is clear that the low concentration of nanostructured Fe3O4 has improved the capacitive performance of the composite via pseudocapacitance charge storage mechanism as well as the enhancement on the specific surface areas of the electrode. However, further increasing of the Fe3O4 content in the electrode is found to distort the capacitive performance and deteriorate the specific surface area of the electrode, mainly due to the aggregation of the Fe3O4 particles within the composite. Additionally, the CV results showed that the Fe3O4/AC nanocomposite electrode in Na2SO3 electrolyte exhibits a better charge storage performance if compared with Na2SO4 solution. It is believed that Fe3O4 nanoparticles can provide favourable surface adsorption sites for sulphite (SO32-) anions which act as catalysts for subsequent redox and intercalation reactions

Electromigration-Induced Flow of Islands and Voids on the Cu(001) Surface

Electromigration-induced flow of islands and voids on the Cu(001) surface is studied at the atomic scale. The basic drift mechanisms are identified using a complete set of energy barriers for adatom hopping on the Cu(001) surface, combined with kinetic Monte Carlo simulations. The energy barriers are calculated by the embedded atom method, and parameterized using a simple model. The dependence of the flow on the temperature, the size of the clusters, and the strength of the applied field is obtained. For both islands and voids it is found that edge diffusion is the dominant mass-transport mechanism. The rate limiting steps are identified. For both islands and voids they involve detachment of atoms from corners into the adjacent edge. The energy barriers for these moves are found to be in good agreement with the activation energy for island/void drift obtained from Arrhenius analysis of the simulation results. The relevance of the results to other FCC(001) metal surfaces and their experimental implications are discussed.Comment: 9 pages, 13 ps figure

Three-algebra for supermembrane and two-algebra for superstring

While string or Yang-Mills theories are based on Lie algebra or two-algebra structure, recent studies indicate that M-theory may require a one higher, three-algebra structure. Here we construct a covariant action for a supermembrane in eleven dimensions, which is invariant under global supersymmetry, local fermionic symmetry and worldvolume diffeomorphism. Our action is classically on-shell equivalent to the celebrated Bergshoeff-Sezgin-Townsend action. However, the novelty is that we spell the action genuinely in terms of Nambu three-brackets: All the derivatives appear through Nambu brackets and hence it manifests the three-algebra structure. Further the double dimensional reduction of our action gives straightforwardly to a type IIA string action featuring two-algebra. Applying the same method, we also construct a covariant action for type IIB superstring, leading directly to the IKKT matrix model.Comment: 1+15 pages, no figure; Refs added, Accepted for publication in JHE

ABJM models in N=3 harmonic superspace

We construct the classical action of the Aharony-Bergman-Jafferis-Maldacena (ABJM) model in the N=3, d=3 harmonic superspace. In such a formulation three out of six supersymmetries are realized off shell while the other three mix the superfields and close on shell. The superfield action involves two hypermultiplet superfields in the bifundamental representation of the gauge group and two Chern-Simons gauge superfields corresponding to the left and right gauge groups. The N=3 superconformal invariance allows only for a minimal gauge interaction of the hypermultiplets. Amazingly, the correct sextic scalar potential of ABJM emerges after the elimination of auxiliary fields. Besides the original U(N)xU(N) ABJM model, we also construct N=3 superfield formulations of some generalizations. For the SU(2)xSU(2) case we give a simple superfield proof of its enhanced N=8 supersymmetry and SO(8) R-symmetry.Comment: 1+35 pages, minor changes, a reference added, published versio

Active Galaxies in the UV

In this article we present different aspects of AGN studies demonstrating the importance of the UV spectral range. Most important diagnostic lines for studying the general physical conditions as well as the metalicities in the central broad line region in AGN are emitted in the UV. The UV/FUV continuum in AGN excites not only the emission lines in the immediate surrounding but it is responsible for the ionization of the intergalactic medium in the early stages of the universe. Variability studies of the emission line profiles of AGN in the UV give us information on the structure and kinematics of the immediate surrounding of the central supermassive black hole as well as on its mass itself.Comment: 29 pages, 13 figures, Ap&SS in pres