778 research outputs found
Galaxy-Galaxy Lensing in the Hubble Deep Field: The Halo Tully-Fisher Relation at Intermediate Redshift
A tangential distortion of background source galaxies around foreground lens
galaxies in the Hubble Deep Field is detected at the 99.3% confidence level. An
important element of our analysis is the use of photometric redshifts to
determine distances of lens and source galaxies and rest-frame B-band
luminosities of the lens galaxies. The lens galaxy halos obey a Tully-Fisher
relation between halo circular velocity and luminosity; the typical lens
galaxy, at a redshift z = 0.6, has a circular velocity of 210 +/-40 km/s at M_B
= -18.5, if q_0 = 0.5. Control tests, in which lens and source positions and
source ellipticities are randomized, confirm the significance level of the
detection quoted above. Furthermore, a marginal signal is also detected from an
independent, fainter sample of source galaxies without photometric redshifts.
Potential systematic effects, such as contamination by aligned satellite
galaxies, the distortion of source shapes by the light of the foreground
galaxies, PSF anisotropies, and contributions from mass distributed on the
scale of galaxy groups are shown to be negligible. A comparison of our result
with the local Tully-Fisher relation indicates that intermediate-redshift
galaxies are fainter than local spirals by 1.0 +/- 0.6 B mag at a fixed
circular velocity. This is consistent with some spectroscopic studies of the
rotation curves of intermediate-redshift galaxies. This result suggests that
the strong increase in the global luminosity density with redshift is dominated
by evolution in the galaxy number density.Comment: Revised version with minor changes. 13 pages, 7 figures, LaTeX2e,
uses emulateapj and multicol styles (included). Accepted by Ap
Estimation of Farm-Forward Regional Economic Impacts for the North Plains Groundwater Conservation District in Texas
Impacts of alternative agricultural water conservation strategies are being evaluated in the Texas Panhandle. Stakeholders have expressed concern that all effects need to be accounted for including the regional economy. A methodology was developed to evaluate the effects on the backward and forward-linked processing sectors and differentiated results are presented.backward-linked, forward-linked, IMPLAN, Ogallala Aquifer, water policy, Resource /Energy Economics and Policy, Q18, Q32, Q38,
AMPK Regulation of Mouse Oocyte Meiotic Resumption in Vitro
We have previously shown that the adenosine analog 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR), an activator of AMP-activated protein kinase (AMPK), stimulates an increase in AMPK activity and induces meiotic resumption in mouse oocytes [Downs, S.M., Hudson, E.R., Hardie, D.G., 2002. A potential role for AMP-activated protein kinase in meiotic induction in mouse oocytes. Dev. Biol, 245, 200–212]. The present study was carried out to better define a causative role for AMPK in oocyte meiotic maturation. When microinjected with a constitutively active AMPK, about 20% of mouse oocytes maintained in meiotic arrest with dibutyryl cAMP (dbcAMP) were stimulated to undergo germinal vesicle breakdown (GVB), while there was no effect of catalytically dead kinase. Western blot analysis revealed that germinal vesicle (GV)-stage oocytes cultured in dbcAMP-containing medium plus AICAR possessed elevated levels of active AMPK, and this was confirmed by AMPK assays using a peptide substrate of AMPK to directly measure AMPK activity. AICAR-induced meiotic resumption and AMPK activation were blocked by compound C or adenine 9-beta-d-arabinofuranoside (araA, a precursor of araATP), both inhibitors of AMPK. Compound C failed to suppress adenosine uptake and phosphorylation, indicating that it did not block AICAR action by preventing its metabolism to the AMP analog, ZMP. 2′-Deoxycoformycin (DCF), a potent adenosine deaminase inhibitor, reversed the inhibitory effect of adenosine on oocyte maturation by modulating intracellular AMP levels and activating AMPK. Rosiglitazone, an anti-diabetic agent, stimulated AMPK activation in oocytes and triggered meiotic resumption. In spontaneously maturing oocytes, GVB was preceded by AMPK activation and blocked by compound C. Collectively, these results support the proposition that active AMPK within mouse oocytes provides a potent meiosis-inducing signal in vitro
Investigation of Systematic Bias in Radiometric Diameter Determination of Near-Earth Asteroids: the Night Emission Simulated Thermal Model (NESTM)
The Near-Earth Asteroid Thermal Model (NEATM, Harris, 1998) has proven to be
a reliable simple thermal model for radiometric diameter determination. However
NEATM assumes zero thermal emission on the night side of an asteroid. We
investigate how this assumption affects the best-fit beaming parameter,
overestimates the effective diameter and underestimates the albedo at large
phase angles, by testing NEATM on thermal IR fluxes generated from simulated
asteroid surfaces with different thermal inertia. We compare NEATM to radar
diameters and find that NEATM overestimates the diameter when the beaming
parameter is fitted to multi-wavelength observations and underestimates the
diameter when the default beaming parameter is used. The Night Emission
Simulated Thermal Model (NESTM) is introduced. NESTM models the night side
temperature as an iso-latitudinal fraction (f) of the maximum day side
temperature (Maximum temperature calculated for NEATM with beaming parameter =
1). A range of f is found for different thermal parameters, which depend on the
thermal inertia. NESTM diameters are compared with NEATM and radar diameters,
and it is shown that NESTM may reduce the systematic bias in overestimating
diameters. It is suggested that a version of the NESTM which assumes the
thermal inertia = 200 S.I. units is adopted as a default model when the solar
phase angle is greater than 45 degrees.Comment: 48 pages, 10 Figures, 5 Table
Enzymically attaching oligosaccharide-linked ‘cargoes’ to cellulose and other commercial polysaccharides via stable covalent bonds
International audienc
The Vehicle, 1966, Vol. 8
Vol. 8
Table of Contents
CommentaryBill Moser & Avis Eaglestonpage 3
The Vengeance of the DeadStephen W. Gibbspage 5
Ode To A MeadowKathleen McCormackpage 12
Row OnDavid Helmpage 13
Sonnet 63R.L. Hudsonpage 14
UntitledKathleen McCormackpage 14
The Pure GoldDavid Helmpage 15
CommunionDavid Helmpage 15
PreludeMichael Baldwinpage 15
The AlbatrossKaren Cooleypage 16
The Albatross (photo)DeWittpage 17
Ruff and the VaseDavid Helmpage 18
LaBelleKathleen McCormackpage 19
Not Quite SoR.L. Hudsonpage 20
Feeling (no number)David Reifpage 21
Song at DuskDavid Helmpage 21
Arcadia RuminationsR.L. Hudsonpage 22
The BarWayne Johnsonpage 25
HelloWilliam Framepage 26
The ProcessJerry DeWittpage 27
The KillingAdrian Beardpage 30
The Amusement Park GameStephen W. Gibbspage 38
DamnMel Tylerpage 40
PainWilliam Framepage 40
UntitledSusan Champlinpage 41
Portrait of A Scholar As A Young ManStephen W. Gibbspage 42
The TimesW.D.Mpage 46
ParadoxW.D.M.page 46
MankindDavid Helmpage 47https://thekeep.eiu.edu/vehicle/1014/thumbnail.jp
The Vehicle, 1966, Vol. 8
Vol. 8
Table of Contents
CommentaryBill Moser & Avis Eaglestonpage 3
The Vengeance of the DeadStephen W. Gibbspage 5
Ode To A MeadowKathleen McCormackpage 12
Row OnDavid Helmpage 13
Sonnet 63R.L. Hudsonpage 14
UntitledKathleen McCormackpage 14
The Pure GoldDavid Helmpage 15
CommunionDavid Helmpage 15
PreludeMichael Baldwinpage 15
The AlbatrossKaren Cooleypage 16
The Albatross (photo)DeWittpage 17
Ruff and the VaseDavid Helmpage 18
LaBelleKathleen McCormackpage 19
Not Quite SoR.L. Hudsonpage 20
Feeling (no number)David Reifpage 21
Song at DuskDavid Helmpage 21
Arcadia RuminationsR.L. Hudsonpage 22
The BarWayne Johnsonpage 25
HelloWilliam Framepage 26
The ProcessJerry DeWittpage 27
The KillingAdrian Beardpage 30
The Amusement Park GameStephen W. Gibbspage 38
DamnMel Tylerpage 40
PainWilliam Framepage 40
UntitledSusan Champlinpage 41
Portrait of A Scholar As A Young ManStephen W. Gibbspage 42
The TimesW.D.Mpage 46
ParadoxW.D.M.page 46
MankindDavid Helmpage 47https://thekeep.eiu.edu/vehicle/1014/thumbnail.jp
Lineage Divergence and Historical Gene Flow in the Chinese Horseshoe Bat (Rhinolophus sinicus)
PMCID: PMC3581519This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Genomic signatures of population decline in the malaria mosquito Anopheles gambiae
Population genomic features such as nucleotide diversity and linkage disequilibrium are expected to be strongly shaped by changes in population size, and might therefore be useful for monitoring the success of a control campaign. In the Kilifi district of Kenya, there has been a marked decline in the abundance of the malaria vector Anopheles gambiae subsequent to the rollout of insecticide-treated bed nets. To investigate whether this decline left a detectable population genomic signature, simulations were performed to compare the effect of population crashes on nucleotide diversity, Tajima's D, and linkage disequilibrium (as measured by the population recombination parameter ρ). Linkage disequilibrium and ρ were estimated for An. gambiae from Kilifi, and compared them to values for Anopheles arabiensis and Anopheles merus at the same location, and for An. gambiae in a location 200 km from Kilifi. In the first simulations ρ changed more rapidly after a population crash than the other statistics, and therefore is a more sensitive indicator of recent population decline. In the empirical data, linkage disequilibrium extends 100-1000 times further, and ρ is 100-1000 times smaller, for the Kilifi population of An. gambiae than for any of the other populations. There were also significant runs of homozygosity in many of the individual An. gambiae mosquitoes from Kilifi. These results support the hypothesis that the recent decline in An. gambiae was driven by the rollout of bed nets. Measuring population genomic parameters in a small sample of individuals before, during and after vector or pest control may be a valuable method of tracking the effectiveness of interventions
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