617 research outputs found
Novel carbohydrate binding modules in the surface anchored α‐amylase of Eubacterium rectale provide a molecular rationale for the range of starches used by this organism in the human gut
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141499/1/mmi13881.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141499/2/mmi13881_am.pd
Finite temperature effects on cosmological baryon diffusion and inhomogeneous Big-Bang nucleosynthesis
We have studied finite temperature corrections to the baryon transport cross
sections and diffusion coefficients. These corrections are based upon the
recently computed renormalized electron mass and the modified state density due
to the background thermal bath in the early universe. It is found that the
optimum nucleosynthesis yields computed using our diffusion coefficients shift
to longer distance scales by a factor of about 3. We also find that the minimum
value of abundance decreases by while and
increase. Effects of these results on constraints from primordial
nucleosynthesis are discussed. In particular, we find that a large baryonic
contribution to the closure density (\Omega_b h_{50}^{2} \lsim 0.4) may be
allowed in inhomogeneous models corrected for finite temperature.Comment: 7 pages, 6 figures, submitted to Phys. Rev.
The mass-loss return from evolved stars to the Large Magellanic Cloud V. The GRAMS carbon-star model grid
The total dust return rate from AGB and RSG star outflows is an important
constraint to galactic chemical evolution models. However, this requires
detailed radiative transfer (RT) modeling of individual stars, which becomes
impractical for large data sets. Another approach is to select the best-fit
spectral energy distribution (SED) from a grid of dust shell models, allowing
for a faster determination of the luminosities and mass-loss rates for entire
samples. We have developed the Grid of RSG and AGB ModelS (GRAMS) to measure
the mass-loss return from evolved stars. The models span the range of stellar,
dust shell and grain properties relevant to evolved stars. In this paper we
present the carbon-star grid and compare our results with data of Large
Magellanic Cloud (LMC) carbon stars from the SAGE and SAGE-Spec programs. We
generate spherically symmetric dust shell models using the 2Dust code, with
hydrostatic models for the central stars. We explore five values of the inner
radius R_in of the dust shell (1.5, 3, 4.5, 7 and 12 R_star). We use amorphous
carbon dust mixed with 10% silicon carbide by mass. The grain sizes follows a
KMH distribution. The models span 26 values of 11.3 um optical depth, ranging
from 0.001 to 4. For each model, 2Dust calculates the output SED from 0.2 to
200 um. Over 12,000 models have dust temperatures below 1800 K. The GRAMS
synthetic photometry is in good agreement with SAGE photometry for LMC
carbon-rich and extreme AGB star candidates, as well as spectroscopically
confirmed carbon stars from the SAGE-Spec study. Our models reproduce the IRAC
colors of most of the extreme AGB star candidates, consistent with the
expectation that a majority of these enshrouded stars have carbon-rich dust.
Finally, we fit the SEDs of some well-studied carbon stars and compare the
resulting luminosities and mass-loss rates with those from previous studies.Comment: 16 pages, 13 figures, accepted for publication in Astronomy &
Astrophysic
Confirmation of a pi_1^0 Exotic Meson in the \eta \pi^0 System
The exclusive reaction , at 18 GeV has been studied with a partial wave analysis on a sample
of 23~492 events from BNL experiment E852. A mass-dependent fit
is consistent with a resonant hypothesis for the wave, thus providing
evidence for a neutral exotic meson with , a mass of MeV, and a width of MeV. New
interpretations of the meson exotics in neutral system observed in
E852 and Crystal Barrel experiments are discussed.Comment: p3, rewording the paragraph (at the bottom) about the phase
variations. p4, rewording paragrath "The second method ..." . p4, at the
bottom of paragrath "The third method ..." added consistent with the results
of methods 1 and 2
Exotic Meson Production in the System observed in the Reaction at 18 GeV/c
This letter reports results from the partial wave analysis of the
final state in collisions at 18GeV/c.
Strong evidence is observed for production of two mesons with exotic quantum
numbers of spin, parity and charge conjugation, in the decay
channel . The mass MeV/c^2 and
width MeV/c^2 of the first state are consistent
with the parameters of the previously observed . The second
resonance with mass MeV/c^2 and width MeV/c^2 agrees very well with predictions from theoretical
models. In addition, the presence of is confirmed with mass MeV/c^2 and width MeV/c^2
and a new state, , is observed with mass
MeV/c^2 and width MeV/c^2. The decay properties of
these last two states are consistent with flux tube model predictions for
hybrid mesons with non-exotic quantum numbers
A Spitzer Space Telescope far-infrared spectral atlas of compact sources in the Magellanic Clouds. I. The Large Magellanic Cloud
[abridged] We present 52-93 micron spectra obtained with Spitzer in the
MIPS-SED mode, of a representative sample of luminous compact far-IR sources in
the LMC. These include carbon stars, OH/IR AGB stars, post-AGB objects and PNe,
RCrB-type star HV2671, OH/IR red supergiants WOHG064 and IRAS05280-6910, B[e]
stars IRAS04530-6916, R66 and R126, Wolf-Rayet star Brey3a, Luminous Blue
Variable R71, supernova remnant N49, a large number of young stellar objects,
compact HII regions and molecular cores, and a background galaxy (z~0.175). We
use the spectra to constrain the presence and temperature of cold dust and the
excitation conditions and shocks within the neutral and ionized gas, in the
circumstellar environments and interfaces with the surrounding ISM. Evolved
stars, including LBV R71, lack cold dust except in some cases where we argue
that this is swept-up ISM. This leads to an estimate of the duration of the
prolific dust-producing phase ("superwind") of several thousand years for both
RSGs and massive AGB stars, with a similar fractional mass loss experienced
despite the different masses. We tentatively detect line emission from neutral
oxygen in the extreme RSG WOHG064, with implications for the wind driving. In
N49, the shock between the supernova ejecta and ISM is revealed by its strong
[OI] 63-micron emission and possibly water vapour; we estimate that 0.2 Msun of
ISM dust was swept up. Some of the compact HII regions display pronounced
[OIII] 88-micron emission. The efficiency of photo-electric heating in the
interfaces of ionized gas and molecular clouds is estimated at 0.1-0.3%. We
confirm earlier indications of a low nitrogen content in the LMC. Evidence for
solid state emission features is found in both young and evolved object; some
of the YSOs are found to contain crystalline water ice.Comment: Accepted for publication in The Astronomical Journal. This paper
accompanies the Summer 2009 SAGE-Spec release of 48 MIPS-SED spectra, but
uses improved spectrum extraction. (Fig. 2 reduced resolution because of
arXiv limit.
The Relationship of Anatomic Variation of Pancreatic Ductal System and Pancreaticobiliary Diseases
The aims of this study were to identify the morphological diversities and anatomical variations of pancreatic ductal system and to define the relationships between pancreatic ductal systems, pancreaticobiliary diseases, and procedure-related complications, including post-ERCP pancreatitis. This study included 582 patients in whom both pancreatic duct (PD) and common bile duct were clearly visible by ERCP. PD systems were categorized into four types according to the relationship between common bile duct and PD. In types A and B, Wirsung duct formed the main PD. In type C, Wirsung duct did not form the main PD. If PD system did not fall into any of these three types, it was categorized as type D. The distribution of types among pancreatic ducts examined was as follows: type A: 491 cases (84.4%), type B: 56 cases (9.6%), type C: 20 cases (3.4%), and type D: 15 cases (2.6%). The anomalous anatomic variations of PD systems were divided into migration, fusion, and duplication anomalies. PD anomalies were noted in 51 patients, of which 19 (3.3%) were fusion anomalies (12 complete pancreas divisum, 7 incomplete pancreas divisum), and 32 (5.5%) were duplication anomalies (5 number variations, 27 form variations). No significant relationships between various PD morphologies and pancreaticobiliary diseases were found. However, post-ERCP hyperamylasemia was more frequently found in types C (41.7%), D (50%) and A (19.8%) than in type B (9.4%). In summary, whether Wirsung duct forms the main PD and the presence or absence of the opening of the Santorini duct are both important factors in determining the development of pancreatitis and hyperamylasemia after ERCP
Kv7 Channels Can Function without Constitutive Calmodulin Tethering
M-channels are voltage-gated potassium channels composed of Kv7.2-7.5 subunits that serve as important regulators of neuronal excitability. Calmodulin binding is required for Kv7 channel function and mutations in Kv7.2 that disrupt calmodulin binding cause Benign Familial Neonatal Convulsions (BFNC), a dominantly inherited human epilepsy. On the basis that Kv7.2 mutants deficient in calmodulin binding are not functional, calmodulin has been defined as an auxiliary subunit of Kv7 channels. However, we have identified a presumably phosphomimetic mutation S511D that permits calmodulin-independent function. Thus, our data reveal that constitutive tethering of calmodulin is not required for Kv7 channel function
ENCODE whole-genome data in the UCSC genome browser (2011 update)
The ENCODE project is an international consortium with a goal of cataloguing all the functional elements in the human genome. The ENCODE Data Coordination Center (DCC) at the University of California, Santa Cruz serves as the central repository for ENCODE data. In this role, the DCC offers a collection of high-throughput, genome-wide data generated with technologies such as ChIP-Seq, RNA-Seq, DNA digestion and others. This data helps illuminate transcription factor-binding sites, histone marks, chromatin accessibility, DNA methylation, RNA expression, RNA binding and other cell-state indicators. It includes sequences with quality scores, alignments, signals calculated from the alignments, and in most cases, element or peak calls calculated from the signal data. Each data set is available for visualization and download via the UCSC Genome Browser (http://genome.ucsc.edu/). ENCODE data can also be retrieved using a metadata system that captures the experimental parameters of each assay. The ENCODE web portal at UCSC (http://encodeproject.org/) provides information about the ENCODE data and links for access
Micro/Nanopatterning of Proteins via Contact Printing Using High Aspect Ratio PMMA Stamps and NanoImprint Apparatus
- …