997 research outputs found
On the nature of prominence emission observed by SDO/AIA
The Prominence-Corona Transition Region (PCTR) plays a key role in the
thermal and pressure equilibrium of solar prominences. Our knowledge of this
interface is limited and several major issues remain open, including the
thermal structure and, in particular, the maximum temperature of the detectable
plasma. The high signal-to-noise ratio of images obtained by the Atmospheric
Imaging Assembly (AIA) on NASA's Solar Dynamics Observatory clearly show that
prominences are often seen in emission in the 171 and 131 bands. We investigate
the temperature sensitivity of these AIA bands for prominence observation, in
order to infer the temperature content in an effort to explain the emission.
Using the CHIANTI atomic database and previously determined prominence
differential emission measure distributions, we build synthetic spectra to
establish the main emission-line contributors in the AIA bands. We find that
the Fe IX line always dominates the 171 band, even in the absence of plasma at
> 10^6 K temperatures, while the 131 band is dominated by Fe VIII. We conclude
that the PCTR has sufficient plasma emitting at > 4 10^5 K to be detected by
AIA.Comment: accepted Ap
A study of various environmental factors on the growth, encystment and survival of free living amoebae : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Microbiology at Massey University
Free-living amoebae (FLA) are soil organisms which have a worldwide distribution. Interest was raised when they were implicated in two fatal and several non-fatal infections in humans.
This investigation involved examination of the role and/or effect of several environmental factors on growth, encystment and cyst survival
of FLA.
The effect of K+, Na+ , Mg+2, Ca+2 and Fe+2/+3 on the growth of
four species of amoebae (Naegleria gruberi, Naegleria fowleri, Acanthamoeba culbertsoni and Acanthamoeba castellanii) was investigated.
Inhibition of growth rate increased as the cation concentration was increased.
The roles of Mg+2 and Ca+2 in encystment were investigated and it
was found that rather than being necessary, they were inhibitory.
The survival of cysts under low temperatures and high cation concentrations was studied. Acanthamoeba proved to be resistant to adverse conditions once encysted. Naegleria were not affected by high cation levels but were adversely affected by low temperatures.
A preliminary identification of two isolates from Ngawha Springs hot pools was undertaken showing both amoebae to be temperature tolerant Naegleria species
Implementing Snow Load Monitoring to Control Reliability of a Stadium Roof
This contribution shows how monitoring can be
used to control reliability of a structure not complying
with the requirements of Eurocodes. A general
methodology to obtain cost-optimal decisions using limit
state design, probabilistic reliability analysis and cost
estimates is utilised in a full-scale case study dealing with
the roof of a stadium located in Northern Italy. The
results demonstrate the potential of monitoring systems
and probabilistic reliability analysis to support decisions
regarding safety measures such as snow removal, or
temporary closure of the stadium
Landscape phage, phage display, stripped phage, biosensors, detection, affinity reagent, nanotechnology, Salmonella typhimurium, Bacillus anthracis
Filamentous phage, such as fd used in this study, are thread-shaped bacterial
viruses. Their outer coat is a tube formed by thousands equal copies of the
major coat protein pVIII. We constructed libraries of random peptides fused to
all pVIII domains and selected phages that act as probes specific for a panel
of test antigens and biological threat agents. Because the viral carrier is
infective, phage borne bio-selective probes can be cloned individually and
propagated indefinitely without needs of their chemical synthesis or
reconstructing. We demonstrated the feasibility of using landscape phages and
their stripped fusion proteins as new bioselective materials that combine
unique characteristics of affinity reagents and self assembling membrane
proteins. Biorecognition layers fabricated from phage-derived probes bind
biological agents and generate detectable signals. The performance of
phage-derived materials as biorecognition films was illustrated by detection of
streptavidin-coated beads, Bacillus anthracis spores and Salmonella typhimurium
cells. With further refinement, the phage-derived analytical platforms for
detecting and monitoring of numerous threat agents may be developed, since the
biodetector films may be obtained from landscape phages selected against any
bacteria, virus or toxin. As elements of field-use detectors, they are superior
to antibodies, since they are inexpensive, highly specific and strong binders,
resistant to high temperatures and environmental stresses.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Solar Flux Emergence Simulations
We simulate the rise through the upper convection zone and emergence through
the solar surface of initially uniform, untwisted, horizontal magnetic flux
with the same entropy as the non-magnetic plasma that is advected into a domain
48 Mm wide from from 20 Mm deep. The magnetic field is advected upward by the
diverging upflows and pulled down in the downdrafts, which produces a hierarchy
of loop like structures of increasingly smaller scale as the surface is
approached. There are significant differences between the behavior of fields of
10 kG and 20 or 40 kG strength at 20 Mm depth. The 10 kG fields have little
effect on the convective flows and show little magnetic buoyancy effects,
reaching the surface in the typical fluid rise time from 20 Mm depth of 32
hours. 20 and 40 kG fields significantly modify the convective flows, leading
to long thin cells of ascending fluid aligned with the magnetic field and their
magnetic buoyancy makes them rise to the surface faster than the fluid rise
time. The 20 kG field produces a large scale magnetic loop that as it emerges
through the surface leads to the formation of a bipolar pore-like structure.Comment: Solar Physics (in press), 12 pages, 13 figur
Cosmological and Black Hole Spacetimes in Twisted Noncommutative Gravity
We derive noncommutative Einstein equations for abelian twists and their
solutions in consistently symmetry reduced sectors, corresponding to twisted
FRW cosmology and Schwarzschild black holes. While some of these solutions must
be rejected as models for physical spacetimes because they contradict
observations, we find also solutions that can be made compatible with low
energy phenomenology, while exhibiting strong noncommutativity at very short
distances and early times.Comment: LaTeX 12 pages, JHEP.st
Kevin M. Garza, Orchestral Conducting
Ouverture Die Weihe des Hauses Op. 124 / Ludwig van Beethoven; Symphony no. 35 in D major Haffner K. 385 / W.A. Mozart; Pastoral / Karel Husa; Four Irish Dances, Op. 126 / Malcolm Arnol
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