14,665 research outputs found
An Interacting Scenario for Dark Energy in Bianchi Type-I Universe
We study the interaction between dark energy (DE) and dark matter (DM) in the
scope of anisotropic bianchi type I space-time. First we derive the general
form of the dark energy equation of state parameter (EoS) in both
non-interacting and interacting cases and then we examine it's future by
applying a hyperbolic scale factor. It is shown that in non-interacting case,
depending on the value of the anisotropy parameter , the dark energy EoS
parameter is varying from phantom to quintessence whereas in interacting case
EoS parameter vary in quintessence region. However, in both cases the dark
energy EoS parameter , ultimately (i. e at ) tends to the
cosmological constant (). Moreover, we fixed the cosmological
bound on the anisotropy parameter by using the recent observational data of
Hubble parameter.Comment: 12 pages, 6 figures, Research in Astronomy and Astrophysics, 201
Utilizing rapid prototyping 3D printer for fabricating flexographic PDMS printing plate
Recently printed electronic field is significantly growth. Printed electronic is to develop electrical devices by printing method. Conventional printing method that has been studied for this kind of printed electronic such as flexographic, micro contact printing, screen printing, gravure and ink jet. In flexographic and microcontact printing, a printing plate is used to transfer the designed and desired pattern to substrate through conformed contact. Therefore printing plate is play a big role in this area. Printing plate making by photopolymer which used in flexographic have limitation in achieving a micro-scale of pattern size. However, printing plate of microcontact printing have an advantages in producing micro, even nano-scale size by PDMS (Polydimethylsiloxane). Hence, rapid prototyping 3D printer was used for developing a PDMS micro-scale printing plate which will be used in reel to reel (R2R) flexographic due to high speed, low cost, mass production of this type of printing process. The flexibility of 3D printer in producing any shape of pattern easily, contributed the success of this study. A nickel plating and glass etching master pattern was used in this study too as master pattern mould since 3D printer has been reached the micro size limitation. The finest multiple solid line array with 1mm width and 2mm gap pattern of printing plate was successfully fabricated by 3D printer master mould due to size limitation of the FDM (Fused Deposition Modeling) 3D printer nozzle itself. However, the micro-scale multiple solid line array of 100micron and 25micron successfully made by nikel platting and glass etching master mould respectively. Those types of printing plate producing method is valueable since it is easy, fast and low cost, used for micro-flexographic in printed electronic field or biomedical application
Interacting Spin-2 Fields
We construct consistent theories of multiple interacting spin-2 fields in
arbitrary spacetime dimensions using a vielbein formulation. We show that these
theories have the additional primary constraints needed to eliminate potential
ghosts, to all orders in the fields, and to all orders beyond any decoupling
limit. We postulate that the number of spin-2 fields interacting at a single
vertex is limited by the number of spacetime dimensions. We then show that, for
the case of two spin-2 fields, the vielbein theory is equivalent to the
recently proposed theories of ghost-free massive gravity and bi-metric gravity.
The vielbein formulation greatly simplifies the proof that these theories have
an extra primary constraint which eliminates the Boulware-Deser ghost.Comment: 42 pages, 3 figures. v3 alternative argument using constrained
spatial vielbeins has been removed (see footnote 3
Evaluating tools to support a new practical classification of diabetes: excellent control may represent misdiagnosis and omission from disease registers is associated with worse control.
To conduct a service evaluation of usability and utility on-line clinical audit tools developed as part of a UK Classification of Diabetes project to improve the categorisation and ultimately management of diabetes
Theory of low transitions in CO discharge lasers
A self consistent theoretical model which couples the electron and heavy particle finite rate kinetics with the optical and fluid dynamic processes has been employed to identify the various parameters and explain the mechanism responsible for producing low lying transitions in slow flowing CO lasers. It is found that lasing on low lying transitions can be achieved at low temperatures for low pressures (or low flow rates) together with high partial pressures of the He and N2. The role of N2 has been identified as an additive responsible for reducing the electron temperature to a range where the transfer of electrical power to the lower vibrational modes of CO is optimum
USF binding sequences from the HS4 insulator element impose early replication timing on a vertebrate replicator
The nuclear genomes of vertebrates show a highly organized program of DNA replication where GC-rich isochores are replicated early in S-phase, while AT-rich isochores are late replicating. GC-rich regions are gene dense and are enriched for active transcription, suggesting a connection between gene regulation and replication timing. Insulator elements can organize independent domains of gene transcription and are suitable candidates for being key regulators of replication timing. We have tested the impact of inserting a strong replication origin flanked by the β-globin HS4 insulator on the replication timing of naturally late replicating regions in two different avian cell types, DT40 (lymphoid) and 6C2 (erythroid). We find that the HS4 insulator has the capacity to impose a shift to earlier replication. This shift requires the presence of HS4 on both sides of the replication origin and results in an advance of replication timing of the target locus from the second half of S-phase to the first half when a transcribed gene is positioned nearby. Moreover, we find that the USF transcription factor binding site is the key cis-element inside the HS4 insulator that controls replication timing. Taken together, our data identify a combination of cis-elements that might constitute the basic unit of multi-replicon megabase-sized early domains of DNA replication
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