33 research outputs found
MESMER: MeerKAT Search for Molecules in the Epoch of Reionization
[Abridged] Observations of molecular gas at all redshifts are critical for
measuring the cosmic evolution in molecular gas density and understanding the
star-formation history of the Universe. The 12CO molecule (J=1-0 transition =
115.27 GHz) is the best proxy for extragalactic H2, which is the gas reservoir
from which star formation occurs, and has been detected out to z~6. Typically,
redshifted high-J lines are observed at mm-wavelengths, the most commonly
targeted systems exhibiting high SFRs (e.g. submm galaxies), and far-IR-bright
QSOs. While the most luminous objects are the most readily observed, detections
of more typical galaxies with modest SFRs are essential for completing the
picture. ALMA will be revolutionary in terms of increasing the detection rate
and pushing the sensitivity limit down to include such galaxies, however the
limited FoV when observing at such high frequencies makes it difficult to use
ALMA for studies of the large-scale structure traced out by molecular gas in
galaxies. This article introduces a strategy for a systematic search for
molecular gas during the EoR (z~7 and above), capitalizing on the fact that the
J=1-0 transition of 12CO enters the upper bands of cm-wave instruments at
high-z. The FoV advantage gained by observing at such frequencies, coupled with
modern broadband correlators allows significant cosmological volumes to be
probed on reasonable timescales. In this article we present an overview of our
future observing programme which has been awarded 6,500 hours as one of the
Large Survey Projects for MeerKAT, the forthcoming South African SKA pathfinder
instrument. Its large FoV and correlator bandwidth, and high-sensitivity
provide unprecedented survey speed for such work. An existing astrophysical
simulation is coupled with instrumental considerations to demonstrate the
feasibility of such observations and predict detection rates.Comment: 7 pages, 4 figures, to appear in the proceedings of "Astronomy with
megastructures: Joint science with the E-ELT and SKA", 10-14 May 2010, Crete,
Greece (Eds: Isobel Hook, Dimitra Rigopoulou, Steve Rawlings and Aris
Karastergiou
Epidermal Growth FactorâPEG Functionalized PAMAM-Pentaethylenehexamine Dendron for Targeted Gene Delivery Produced by Click Chemistry
Aim of this study was the site-specific conjugation of an epidermal growth factor (EGF)-polyethylene glycol (PEG) chain by click chemistry onto a poly(amido amine) (PAMAM) dendron, as a key step toward defined multifunctional carriers for targeted gene delivery. For this purpose, at first propargyl amine cored PAMAM dendrons with ester ends were synthesized. The chain terminal ester groups were then modified by oligoamines with different secondary amino densities. The oligoamine-modified PAMAM dendrons were well biocompatible, as demonstrated in cytotoxicity assays. Among the different oligoamine-modified dendrons, PAMAM-pentaethylenehexamine (PEHA) dendron polyplexes displayed the best gene transfer ability. Conjugation of PAMAM-PEHA dendron with PEG spacer was conducted via click reaction, which was performed before amidation with PEHA. The resultant PEG-PAMAM-PEHA copolymer was then coupled with EGF ligand. pDNA transfections in HuH-7 hepatocellular carcinoma cells showed a 10-fold higher efficiency with the polyplexes containing conjugated EGF as compared to the ligand-free ones, demonstrating the concept of ligand targeting. Overall gene transfer efficiencies, however, were moderate, suggesting that additional measures for overcoming subsequent intracellular bottlenecks in delivery have to be taken
Expectativas racionais e eficiĂȘncia informacional: anĂĄlise do mercado acionĂĄrio brasileiro no perĂodo 1997-1999
FusÔes e aquisiçÔes de empresas brasileiras: criação de valor e sinergias operacionais
SciPy 1.0: fundamental algorithms for scientific computing in Python.
SciPy is an open-source scientific computing library for the Python programming language. Since its initial release in 2001, SciPy has become a de facto standard for leveraging scientific algorithms in Python, with over 600 unique code contributors, thousands of dependent packages, over 100,000 dependent repositories and millions of downloads per year. In this work, we provide an overview of the capabilities and development practices of SciPy 1.0 and highlight some recent technical developments