591 research outputs found
Human adipose stromal cell therapy improves survival and reduces renal inflammation and capillary rarefaction in acute kidney injury
Damage to endothelial cells contributes to acute kidney injury (AKI) by causing impaired perfusion, while the permanent loss of the capillary network following AKI has been suggested to promote chronic kidney disease. Therefore, strategies to protect renal vasculature may impact both short-term recovery and long-term functional preservation post-AKI. Human adipose stromal cells (hASCs) possess pro-angiogenic and anti-inflammatory properties and therefore have been tested as a therapeutic agent to treat ischaemic conditions. This study evaluated hASC potential to facilitate recovery from AKI with specific attention to capillary preservation and inflammation. Male Sprague Dawley rats were subjected to bilateral ischaemia/reperfusion and allowed to recover for either two or seven days. At the time of reperfusion, hASCs or vehicle was injected into the suprarenal abdominal aorta. hASC-treated rats had significantly greater survival compared to vehicle-treated rats (88.7% versus 69.3%). hASC treatment showed hastened recovery as demonstrated by lower creatinine levels at 48 hrs, while tubular damage was significantly reduced at 48 hrs. hASC treatment resulted in a significant decrease in total T cell and Th17 cell infiltration into injured kidneys at 2 days post-AKI, but an increase in accumulation of regulatory T cells. By day 7, hASC-treated rats showed significantly attenuated capillary rarefaction in the cortex (15% versus 5%) and outer medulla (36% versus 18%) compared to vehicle-treated rats as well as reduced accumulation of interstitial alpha-smooth muscle actin-positive myofibroblasts. These results suggest for the first time that hASCs improve recovery from I/R-induced injury by mechanisms that contribute to decrease in inflammation and preservation of peritubular capillaries
The Oldest Stars of the Extremely Metal-Poor Local Group Dwarf Irregular Galaxy Leo A
We present deep Hubble Space Telescope single-star photometry of Leo A in B,
V, and I. Our new field of view is offset from the centrally located field
observed by Tolstoy et al. (1998) in order to expose the halo population of
this galaxy. We report the detection of metal-poor red horizontal branch stars,
which demonstrate that Leo A is not a young galaxy. In fact, Leo A is as least
as old as metal-poor Galactic Globular Clusters which exhibit red horizontal
branches, and are considered to have a minimum age of about 9 Gyr. We discuss
the distance to Leo A, and perform an extensive comparison of the data with
stellar isochrones. For a distance modulus of 24.5, the data are better than
50% complete down to absolute magnitudes of 2 or more. We can easily identify
stars with metallicities between 0.0001 and 0.0004, and ages between about 5
and 10 Gyr, in their post-main-sequence phases, but lack the detection of
main-sequence turnoffs which would provide unambiguous proof of ancient (>10
Gyr) stellar generations. Blue horizontal branch stars are above the detection
limits, but difficult to distinguish from young stars with similar colors and
magnitudes. Synthetic color-magnitude diagrams show it is possible to populate
the blue horizontal branch in the halo of Leo A. The models also suggest ~50%
of the total astrated mass in our pointing to be attributed to an ancient (>10
Gyr) stellar population. We conclude that Leo A started to form stars at least
about 9 Gyr ago. Leo A exhibits an extremely low oxygen abundance, of only 3%
of Solar, in its ionized interstellar medium. The existence of old stars in
this very oxygen-deficient galaxy illustrates that a low oxygen abundance does
not preclude a history of early star formation.Comment: 44 pages, 18 figures, accepted for publication in the August 2002
issue of AJ. High resolution figures is available at
http://www.astro.spbu.ru/staff/dio/preprints.htm
A Guide to Localized Frames and Applications to Galerkin-like Representations of Operators
This chapter offers a detailed survey on intrinsically localized frames and
the corresponding matrix representation of operators. We re-investigate the
properties of localized frames and the associated Banach spaces in full detail.
We investigate the representation of operators using localized frames in a
Galerkin-type scheme. We show how the boundedness and the invertibility of
matrices and operators are linked and give some sufficient and necessary
conditions for the boundedness of operators between the associated Banach
spaces.Comment: 32 page
A New Paradigm for Large Earthquakes in Stable Continental Plate Interiors
Large earthquakes within stable continental regions (SCR) show that significant amounts of elastic strain can be released on geological structures far from plate boundary faults, where the vast majority of the Earth's seismic activity takes place. SCR earthquakes show spatial and temporal patterns that differ from those at plate boundaries and occur in regions where tectonic loading rates are negligible. However, in the absence of a more appropriate model, they are traditionally viewed as analogous to their plate boundary counterparts, occuring when the accrual of tectonic stress localized at long-lived active faults reaches failure threshold. Here we argue that SCR earthquakes are better explained by transient perturbations of local stress or fault strength that release elastic energy from a pre-stressed lithosphere. As a result, SCR earthquakes can occur in regions with no previous seismicity and no surface evidence for strain accumulation. They need not repeat, since the tectonic loading rate is close to zero. Therefore, concepts of recurrence time or fault slip rate do not apply. As a consequence, seismic hazard in SCRs is likely more spatially distributed than indicated by paleoearthquakes, current seismicity, or geodetic strain rates
The ATLAS Readout System for LHC Runs 2 and 3
The ReadOut System (ROS) is a central part of the data acquisition (DAQ)
system of the ATLAS Experiment at the CERN Large Hadron Collider (LHC). The
system is responsible for receiving and buffering event data from all detector
subsystems and serving these to the High Level Trigger (HLT) system via a 10
GbE network, discarding or transporting data onward once the trigger has
completed its selection process. The ATLAS ROS was completely replaced during
the 2013-2014 experimental shutdown in order to meet the demanding conditions
expected during LHC Run 2 and Run 3 (2015-2025). The ROS consists of roughly
one hundred Linux-based 2U-high rack-mounted servers equipped with PCIe I/O
cards and 10 GbE interfaces. This paper documents the system requirements for
LHC Runs 2 and 3 and the design choices taken to meet them. The results of
performance measurements and the re-use of ROS technology for the development
of data sources, test platforms for other systems, and another ATLAS DAQ system
component, namely the Region of Interest Builder (RoIB), are also discussed.
Finally performance results for Run 2 operations are presented before looking
at the upgrade for Run 3.Comment: 40 pages, 18 figures, journal pape
Strategies for fitting nonlinear ecological models in R, AD Model Builder, and BUGS
Summary: 1. Ecologists often use nonlinear fitting techniques to estimate the parameters of complex ecological models, with attendant frustration. This paper compares three open-source model fitting tools and discusses general strategies for defining and fitting models. 2. R is convenient and (relatively) easy to learn, AD Model Builder is fast and robust but comes with a steep learning curve, while BUGS provides the greatest flexibility at the price of speed. 3. Our model-fitting suggestions range from general cultural advice (where possible, use the tools and models that are most common in your subfield) to specific suggestions about how to change the mathematical description of models to make them more amenable to parameter estimation. 4. A companion web site (https://groups.nceas.ucsb.edu/nonlinear-modeling/projects) presents detailed examples of application of the three tools to a variety of typical ecological estimation problems; each example links both to a detailed project report and to full source code and data
Procedural and physical interventions for vaccine injections systematic review of randomized controlled trials and quasi-randomized controlled trials
Background: This systematic review evaluated the effectiveness of physical and procedural interventions for reducing pain and related outcomes during vaccination. Design/Methods: Databases were searched using a broad search strategy to identify relevant randomized and quasi-randomized controlled trials. Data were extracted according to procedure phase (preprocedure, acute, recovery, and combinations of these) and pooled using established methods. Results: A total of 31 studies were included. Acute infant distress was diminished during intramuscular injection without aspiration (n=313): standardized mean difference (SMD) -0.82 (95% confidence interval [CI]: -1.18, -0.46). Injecting the most painful vaccine last during vaccinations reduced acute infant distress (n=196): SMD -0.69 (95%CI: -0.98, -0.4). Simultaneous injections reduced acute infant distress compared with sequential injections (n=172): SMD -0.56 (95%CI: -0.87, -0.25). There was no benefit of simultaneous injections in children. Less infant distress during the acute and recovery phases combined occurred with vastus lateralis (vs. deltoid) injections (n=185): SMD -0.70 (95%CI: -1.00, -0.41). Skin-to-skin contact in neonates (n=736) reduced acute distress: SMD -0.65 (95% CI: -1.05, -0.25). Holding infants reduced acute distress after removal of the data from 1 methodologically diverse study (n=107): SMD -1.25 (95% CI: -2.05, -0.46). Holding after vaccination (n=417) reduced infant distress during the acute and recovery phases combined: SMD -0.65 (95% CI: -1.08, -0.22). Self-reported fear was reduced for children positioned upright (n=107): SMD -0.39 (95% CI: -0.77, -0.01). Non-nutritive sucking (n=186) reduced acute distress in infants: SMD -1.88 (95% CI: -2.57, -1.18). Manual tactile stimulation did not reduce pain across the lifespan. An external vibrating device and cold reduced pain in children (n=145): SMD -1.23 (95% CI: -1.58, -0.87). There was no benefit of warming the vaccine in adults. Muscle tension was beneficial in selected indices of fainting in adolescents and adults. Conclusions: Interventions with evidence of benefit in select populations include: no aspiration, injecting most painful vaccine last, simultaneous injections, vastus lateralis injection, positioning interventions, non-nutritive sucking, external vibrating device with cold, and muscle tension
Author Correction: A consensus-based transparency checklist.
An amendment to this paper has been published and can be accessed via a link at the top of the paper
Different Origins of Gamma Rhythm and High-Gamma Activity in Macaque Visual Cortex
High-gamma (80–200 Hz) activity can be dissociated from gamma rhythms in
the monkey cortex, and appears largely to reflect spiking activity in the
vicinity of the electrode
Planck pre-launch status: The optical system
Planck is a scientific satellite that represents the next milestone in space-based research related to the cosmic microwave background, and in many other astrophysical fields. Planck was launched on 14 May of 2009 and is now operational. The uncertainty in the optical response of its detectors is a key factor allowing Planck to achieve its scientific objectives. More than a decade of analysis and measurements have gone into achieving the required performances. In this paper, we describe the main aspects of the Planck optics that are relevant to science, and the estimated in-flight performance, based on the knowledge available at the time of launch. We also briefly describe the impact of the major systematic effects of optical origin, and the concept of in-flight optical calibration. Detailed discussions of related areas are provided in accompanying papers
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