4,933 research outputs found
EC80-553 What to Do Until the Doctor Comes....First Aid : A Guide for Emergency Medical Care
Extension circular 80-553 discusses What to do until the doctor comes: first aid, a guide for emergency medical care
Mapping the inner regions of the polar disk galaxy NGC4650A with MUSE
[abridged] The polar disk galaxy NGC4650A was observed during the
commissioning of the MUSE at the ESO VLT to obtain the first 2D map of the
velocity and velocity dispersion for both stars and gas. The new MUSE data
allow the analysis of the structure and kinematics towards the central regions
of NGC4650A, where the two components co-exist. These regions were unexplored
by the previous long-slit literature data available for this galaxy. The
extended view of NGC~4650A given by the MUSE data is a galaxy made of two
perpendicular disks that remain distinct and drive the kinematics right into
the very centre of this object. In order to match this observed structure for
NGC4650A, we constructed a multicomponent mass model made by the combined
projection of two disks. By comparing the observations with the 2D kinematics
derived from the model, we found that the modelled mass distribution in these
two disks can, on average, account for the complex kinematics revealed by the
MUSE data, also in the central regions of the galaxy where the two components
coexist. This result is a strong constraint on the dynamics and formation
history of this galaxy; it further supports the idea that polar disk galaxies
like NGC~4650A were formed through the accretion of material that has different
angular momentum.Comment: 14 pages, 10 figures; accepted for publication in Astronomy &
Astrophysic
Probing dark energy with the shear-ratio geometric test
We adapt the Jain--Taylor (2003) shear-ratio geometric lensing method to
measure the dark energy equation of state, and its time derivative from dark
matter haloes in cosmologies with arbitrary spatial curvature. The full
shear-ratio covariance matrix is calculated for lensed sources, including the
intervening large-scale structure and photometric redshift errors as additional
sources of noise, and a maximum likelihood method for applying the test is
presented. Combining with the expected results from the CMB we design an
optimal survey for probing dark energy. A targeted survey imaging 60 of the
largest clusters in a hemisphere with 5-band optical photometric redshifts to a
median galaxy depth of zm=0.9 could measure w0 to a marginal 1-sigma error of
w0=0.5. We marginalize over all other parameters including wa, where
the equation of state is parameterized in terms of scale factor a as
w(a)=w0+wa(1-a). For higher accuracy a large-scale photometric redshift survey
is required. Such a near-future 5-band survey covering 10,000 square degrees to
z_m=0.7 could measure w0 to w0=0.075 and wa=0.33. A stronger
combined constraint is measured at a pivot redshift zp=0.27 of
w(zp)=0.0298. We compare and combine the geometric test with the
cosmological and dark energy parameters measured from planned Baryon Acoustic
Oscillation (BAO) and supernova Type Ia experiments, and find that the
geometric test results combine with a significant reduction in errors due to
different degeneracies. A combination of geometric lensing, CMB and BAO
experiments could achieve a pivot redshift constraint of w(zp)=0.020 at
zp=0.62. Simple relations are presented that show how our lensing results can
be scaled to other telescope classes and survey parameters.Comment: 30 pages, 29 figures. Accepted to MNRAS. Figures now grayscale.
Scaling between SIS and NFW profiles is now mass, redshift and cosmology
dependant. Further discussion on photometric redshifts and outlier
Mapping the 3-D Dark Matter potential with weak shear
We investigate the practical implementation of Taylor's (2002) 3-dimensional
gravitational potential reconstruction method using weak gravitational lensing,
together with the requisite reconstruction of the lensing potential. This
methodology calculates the 3-D gravitational potential given a knowledge of
shear estimates and redshifts for a set of galaxies. We analytically estimate
the noise expected in the reconstructed gravitational field, taking into
account the uncertainties associated with a finite survey, photometric redshift
uncertainty, redshift-space distortions, and multiple scattering events. In
order to implement this approach for future data analysis, we simulate the
lensing distortion fields due to various mass distributions. We create
catalogues of galaxies sampling this distortion in three dimensions, with
realistic spatial distribution and intrinsic ellipticity for both ground-based
and space-based surveys. Using the resulting catalogues of galaxy position and
shear, we demonstrate that it is possible to reconstruct the lensing and
gravitational potentials with our method. For example, we demonstrate that a
typical ground-based shear survey with redshift limit z=1 and photometric
redshifts with error Delta z=0.05 is directly able to measure the 3-D
gravitational potential for mass concentrations >10^14 M_\odot between
0.1<z<0.5, and can statistically measure the potential at much lower mass
limits. The intrinsic ellipticity of objects is found to be a serious source of
noise for the gravitational potential, which can be overcome by Wiener
filtering or examining the potential statistically over many fields. We examine
the use of the 3-D lensing potential to measure mass and position of clusters
in 3-D, and to detect clusters behind clusters.Comment: 21 pages, including 24 figures, submitted to MNRA
Previous attentional set can induce an attentional blink with task-irrelevant initial targets
Identification of a second target is often impaired by the requirement to process a prior target in a rapid serial visual presentation (RSVP). This is termed the attentional blink. Even when the first target is task-irrelevant an attentional blink may occur providing this first target shares similar features with the second target (contingent capture). An RSVP experiment was undertaken to assess whether this first target can still cause an attentional blink when it did not require a response and did not share any features with the following target. The results revealed that such task-irrelevant targets can induce an attentional blink providing that they were task-relevant on a previous block of trials. This suggests that irrelevant focal stimuli can distract attention on the basis of a previous attentional set
The Communication Cost of Simulating Bell Correlations
What classical resources are required to simulate quantum correlations? For
the simplest and most important case of local projective measurements on an
entangled Bell pair state, we show that exact simulation is possible using
local hidden variables augmented by just one bit of classical communication.
Certain quantum teleportation experiments, which teleport a single qubit,
therefore admit a local hidden variables model.Comment: 4 pages, 2 figures; reference adde
A SAURON look at galaxy bulges
Kinematic and population studies show that bulges are generally rotationally
flattened systems similar to low-luminosity ellipticals. However, observations
with state-of-the-art integral field spectrographs, such as SAURON, indicate
that the situation is much more complex, and allow us to investigate phenomena
such as triaxiality, kinematic decoupling and population substructure, and to
study their connection to current formation and evolution scenarios for bulges
of early-type galaxies. We present the examples of two S0 bulges from galaxies
in our sample of nearby galaxies: one that shows all the properties expected
from classical bulges (NGC5866), and another case that presents kinematic
features appropriate for barred disk galaxies (NGC7332).Comment: 4 pages, 3 figures, accepted for publishing in AN (refereed conf.
proc. of the Euro3D Science workshop, IoA Cambridge, May 2003
Evidence of Rapid Phenocryst Growth of Olivine During Ascent in Basalts From the Big Pine Volcanic Field: Application of OlivineâMelt Thermometry and Hygrometry at the Liquidus
The Quaternary Big Pine (BP) volcanic field in eastern California is notable for the occurrence of mantle xenoliths in several flows. This points to rapid ascent of basalt through the crust and precludes prolonged storage in a crustal reservoir. In this study, the hypothesis of phenocryst growth during ascent is tested for several basalts (13â7 wt% MgO) and shown to be viable. Phenocrysts of olivine and clinopyroxene frequently display diffusionâlimited growth textures, and clinopyroxene compositions are consistent with polybaric crystallization. When the most Mgârich olivine in each sample is paired with the wholeârock composition, resulting Fe2+âMgKD(olivineâmelt) values (0.31â0.36) match those calculated from literature models (0.32â0.36). Application of a Mgâ and a Niâbased olivineâmelt thermometer from the literature, both calibrated on the same experimental data set, leads to two sets of temperatures that vary linearly with wholeârock MgO wt%. Because the Ni thermometer is independent of water content, it provides the actual temperature at the onset of olivine crystallization (1247â1097°C), whereas the Mg thermometer gives the temperature under anhydrous conditions and thus allows ÎT (=TMg â TNi = depression of liquidus due to water) to be obtained. The average ÎT for all samples is ~59°C, which is consistent with analyzed water contents of 1.5â3.0 wt% in olivineâhosted melt inclusions from the literature. Because the application of olivineâmelt thermometry/hygrometry at the liquidus only requires microprobe analyses of olivine combined with wholeârock compositions, it can be used to obtain large global data sets of the temperature and water contents of basalts from different tectonic settings.Plain Language SummaryBasaltic lavas are a window into their mantle source regions, which is why it is important to determine their temperatures and water contents. In this study, a new approach that allows these two parameters to be quantified is demonstrated for basalts from the Big Pine volcanic field, CA. They were targeted because many contain chunks of dense mantle rocks, which precludes storage in a crustal magma chamber and points to direct ascent from the mantle to the surface along fractures. Two hypotheses are proposed, tested, and shown to be viable in this study: (1) olivine crystallized in the basalts during ascent, and (2) the most Mgârich olivine analyzed in each basalt represents the first olivine to grow during ascent. This enables the most Mgârich olivine to be paired with the wholeârock composition in the application of olivineâmelt thermometry and hygrometry. The results match those from published, independent studies. The success of this approach paves the way for the attainment of large, highâquality data sets for basalts from a wide variety of tectonic settings. This, in turn, may allow global variations in mantle temperature and volatile content to be mapped in greater detail and better understood.Key PointsRapid phenocryst growth occurs during ascent in Mgârich basalts (some carry mantle xenoliths) from the Big Pine volcanic field, CAThe most Mgârich olivine can be paired with the wholeârock composition to apply olivineâmelt thermometry/hygrometry at the liquidusLarge, highâquality data sets on the temperature and water content of basalts from various tectonic settings can be obtained by this methodPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163434/3/ggge22329-sup-0001-2020GC009264-SI.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163434/2/ggge22329.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163434/1/ggge22329_am.pd
Interactions of Bacillus Mojavensis and Fusarium Verticillioides With a Benzoxazolinone (Boa) and Its Transformation Product, Apo
En:Journal of Chemical Ecology (2007, vol. 33, n. 10, p. 1885-1897)The benzoxazolinones, specifically benzoxazolin-2(3H)-one (BOA), are important transformation products of the benzoxazinones that can serve as allelochemicals providing resistance to maize from pathogenic bacteria, fungi, and insects. However, maize pathogens such as Fusarium verticillioides are capable of detoxifying the benzoxazolinones to 2-aminophenol (AP), which is converted to the less toxic N-(2-hydroxyphenyl) malonamic acid (HPMA) and 2-acetamidophenol (HPAA). As biocontrol strategies that utilize a species of endophytic bacterium, Bacillus mojavensis, are considered efficacious as a control of this Fusarium species, the in vitro transformation and effects of BOA on growth of this bacterium was examined relative to its interaction with strains of F. verticillioides. The results showed that a red pigment was produced and accumulated only on BOA-amended media when wild type and the progeny of genetic crosses of F. verticillioides are cultured in the presence of the bacterium. The pigment was identified as 2-amino-3H-phenoxazin-3-one (APO), which is a stable product. The results indicate that the bacterium interacts with the fungus preventing the usual transformation of AP to the nontoxic HPMA, resulting in the accumulation of higher amounts of APO than when the fungus is cultured alone. APO is highly toxic to F. verticillioides and other organisms. Thus, an enhanced biocontrol is suggested by this in vitro study.
=580 $aEn:Journal of Chemical Ecolog
OASIS High-Resolution Integral Field Spectroscopy of the SAURON Ellipticals and Lenticulars
We present a summary of high-spatial resolution follow-up observations of the
elliptical (E) and lenticular (S0) galaxies in the SAURON survey using the
OASIS integral field spectrograph. The OASIS observations explore the central
8x10" regions of these galaxies using a spatial sampling four times higher than
SAURON, often revealing previously undiscovered features. Around 75% (31/48) of
the SAURON E/S0s with central velocity dispersion >= 120 km/s were observed
with OASIS, covering well the original SAURON representative sample. We present
here an overview of this follow-up survey, and some preliminary results on
individual objects, including a previously unreported counter-rotating core in
NGC 4382; the decoupled stellar and gas velocity fields of NGC 2768; and the
strong age gradient towards the centre of NGC 3489.Comment: 4 pages, 5 figures. Accepted for publication in Astron. Nachr. as
refereed proceedings of Euro3D Science Workshop, IoA Cambridge, May 200
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