692 research outputs found
Examining the Decline in the C~IV Content of the Universe over 4.3 ≲ z ≲ 6.3 using the E-XQR-30 Sample
Intervening C iv absorbers are key tracers of metal-enriched gas in galaxy haloes over cosmic time. Previous studies suggest that the C iv cosmic mass density ([Math Processing Error]) decreases slowly over 1.5 [Math Processing Error] 5 before declining rapidly at z ≳ 5, but the cause of this downturn is poorly understood. We characterize the [Math Processing Error] evolution over 4.3 ≲ z ≲ 6.3 using 260 absorbers found in 42 XSHOOTER spectra of z ∼ 6 quasars, of which 30 come from the ESO Large Program XQR-30. The large sample enables us to robustly constrain the rate and timing of the downturn. We find that [Math Processing Error] decreases by a factor of 4.8 ± 2.0 over the ∼300 Myr interval between z ∼ 4.7 and ∼5.8. The slope of the column density (log N) distribution function does not change, suggesting that C iv absorption is suppressed approximately uniformly across 13.2 ≤ log N/cm−2 < 15.0. Assuming that the carbon content of galaxy haloes evolves as the integral of the cosmic star formation rate density (with some delay due to stellar lifetimes and outflow travel times), we show that chemical evolution alone could plausibly explain the fast decline in [Math Processing Error] over 4.3 ≲ z ≲ 6.3. However, the C iv/C ii ratio decreases at the highest redshifts, so the accelerated decline in [Math Processing Error] at z ≳ 5 may be more naturally explained by rapid changes in the gas ionization state driven by evolution of the UV background towards the end of hydrogen reionization
Behaviour of motor unit action potential rate, estimated from surface EMG, as a measure of muscle activation level
BACKGROUND: Surface electromyography (EMG) parameters such as root-mean-square value (RMS) are commonly used to assess the muscle activation level that is imposed by the central nervous system (CNS). However, RMS is influenced not only by motor control aspects, but also by peripheral properties of the muscle and recording setup. To assess motor control separately, the number of motor unit action potentials (MUAPs) per second, or MUAP Rate (MR) is a potentially useful measure. MR is the sum of the firing rates of the contributing MUs and as such reflects the two parameters that the CNS uses for motor control: number of MUs and firing rate. MR can be estimated from multi-channel surface EMG recordings. The objective of this study was to explore the behaviour of estimated MR (eMR) in relation to number of active MUs and firing rate. Furthermore, the influence of parameters related to peripheral muscle properties and recording setup (number of fibers per MU, fiber diameter, thickness of the subcutaneous layer, signal-to-noise-ratio) on eMR was compared with their influence on RMS. METHODS: Physiological parameters were varied in a simulation model that generated multi-channel EMG signals. The behaviour of eMR in simulated conditions was compared with its behaviour in experimental conditions. Experimental data was obtained from the upper trapezius muscle during a shoulder elevation task (20–100 N). RESULTS: The simulations showed strong, monotonously increasing relations between eMR and number of active MUs and firing rate (r(2 )> 0.95). Because of unrecognized superimpositions of MUAPs, eMR was substantially lower than the actual MUAP Rate (aMR). The percentage of detected MUAPs decreased with aMR, but the relation between eMR and aMR was rather stable in all simulated conditions. In contrast to RMS, eMR was not affected by number of fibers per MU, fiber diameter and thickness of the subcutaneous layer. Experimental data showed a strong relation between eMR and force (individual second order polynomial regression: 0.96 < r(2 )< 0.99). CONCLUSION: Although the actual number of MUAPs in the signal cannot be accurately extracted with the present method, the stability of the relation between eMR and aMR and its independence of muscle properties make eMR a suitable parameter to assess the input from the CNS to the muscle at low contraction levels non-invasively
A meta-analysis of the efficacy of preoperative surgical safety checklists to improve perioperative outcomes
Background. Meta-analyses of the implementation of a surgical safety checklist (SSC) in observational studies have shown a significant decrease in mortality and surgical complications.Objective. To determine the efficacy of the SSC using data from randomised controlled trials (RCTs).Methods. This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered with PROSPERO (CRD42015017546). A comprehensive search of six databases was conducted using the OvidSP search engine.Results. Four hundred and sixty-four citations revealed three eligible trials conducted in tertiary hospitals and a community hospital, with a total of 6 060 patients. All trials had allocation concealment bias and a lack of blinding of participants and personnel. A single trial that contributed 5 295 of the 6 060 patients to the meta-analysis had no detection, attrition or reporting biases. The SSC was associated with significantly decreased mortality (risk ratio (RR) 0.59, 95% confidence interval (CI) 0.42 - 0.85; p=0.0004; I2=0%) and surgical complications (RR 0.64, 95% CI 0.57 - 0.71; p<0.00001; I2=0%). The efficacy of the SSC on specific surgical complications was as follows: respiratory complications RR 0.59, 95% CI 0.21 - 1.70; p=0.33, cardiac complications RR 0.74, 95% CI 0.28 - 1.95; p=0.54, infectious complications RR 0.61, 95% CI 0.29 - 1.27; p=0.18, and perioperative bleeding RR 0.36, 95% CI 0.23 - 0.56; p<0.00001.Conclusions. There is sufficient RCT evidence to suggest that SSCs decrease hospital mortality and surgical outcomes in tertiary and community hospitals. However, randomised evidence of the efficacy of the SSC at rural hospital level is absent
The quasar feedback survey: discovering hidden Radio-AGN and their connection to the host galaxy ionized gas
We present the first results from the Quasar Feedback Survey, a sample of 42 z 1042.1 ergs s−1) with moderate radio luminosities (i.e. L1.4GHz > 1023.4 W Hz−1; median L1.4GHz = 5.9 × 1023 W Hz−1). Using high spatial resolution (∼0.3–1 arcsec), 1.5–6 GHz radio images from the Very Large Array, we find that 67 per cent of the sample have spatially extended radio features on ∼1–60 kpc scales. The radio sizes and morphologies suggest that these may be lower radio luminosity versions of compact, radio-loud AGNs. By combining the radio-to-infrared excess parameter, spectral index, radio morphology, and brightness temperature, we find radio emission in at least 57 per cent of the sample that is associated with AGN-related processes (e.g. jets, quasar-driven winds, or coronal emission). This is despite only 9.5–21 per cent being classified as radio-loud using traditional criteria. The origin of the radio emission in the remainder of the sample is unclear. We find that both the established anticorrelation between radio size and the width of the [O III] line, and the known trend for the most [O III] luminous AGNs to be associated with spatially extended radio emission, also hold for our sample of moderate radio luminosity quasars. These observations add to the growing evidence of a connection between the radio emission and ionized gas in quasar host galaxies. This work lays the foundation for deeper investigations into the drivers and impact of feedback in this unique sample
Unchanged muscle fiber conduction velocity relates to mild acidosis during exhaustive bicycling
Muscle fiber conduction velocity (MFCV) has often been shown to decrease during standardized fatiguing isometric contractions. However, several studies have indicated that the MFCV may remain constant during fatiguing dynamic exercise. It was investigated if these observations can be related to the absence of a large decrease in pH and if MFCV can be considered as a good indicator of acidosis, also during dynamic bicycle exercise. High-density surface electromyography (HDsEMG) was combined with read-outs of muscle energetics recorded by in vivo 31P magnetic resonance spectroscopy (MRS). Measurements were performed during serial exhausting bouts of bicycle exercise at three different workloads. The HDsEMG recordings revealed a small and incoherent variation of MFCV during all high-intensity exercise bouts. 31P MRS spectra revealed a moderate decrease in pH at the end of exercise (~0.3 units down to 6.8) and a rapid ancillary drop to pH 6.5 during recovery 30 s post-exercise. This additional degree of acidification caused a significant decrease in MFCV during cycling immediately after the rest period. From the data a significant correlation between MFCV and [H+] ([H+] = 10−pH) was calculated (p < 0.001, Pearson’s R = −0.87). Our results confirmed the previous observations of MFCV remaining constant during fatiguing dynamic exercise. A constant MFCV is in line with a low degree of acidification, considering the presence of a correlation between pH and MFCV after further increasing acidification
Therapeutic expression of human clotting factors IX and X following adeno-associated viral vector-mediated intrauterine gene transfer in early-gestation fetal macaques
Adeno-associated viral vectors (AAVs) achieve stable therapeutic expression without long-term toxicity in adults with hemophilia. To avert irreversible complications in congenital disorders producing early pathogenesis, safety and efficacy of AAV-intrauterine gene transfer (IUGT) requires assessment. We therefore performed IUGT of AAV5 or -8 with liver-specific promoter-1 encoding either human coagulation factors IX (hFIX) or X (hFX) into Macaca fascicularis fetuses at ∼0.4 gestation. The initial cohort received 1 × 1012 vector genomes (vgs) of AAV5-hFIX ( n = 5; 0.45 × 1013 vg/kg birth weight), resulting in ∼3.0% hFIX at birth and 0.6-6.8% over 19-51 mo. The next cohort received 0.2-1 × 1013 vg boluses. AAV5-hFX animals ( n = 3; 3.57 × 1013 vg/kg) expressed 35 mo. Low expressers (<1%, n = 3) were postnatally challenged with 2 × 1011 vg/kg AAV5 resulting in 2.4-13.2% expression and demonstrating acquired tolerance. Linear amplification-mediated-PCR analysis demonstrated random integration of 57-88% of AAV sequences retrieved from hepatocytes with no events occurring in or near oncogenesis-associated genes. Thus, early-IUGT in macaques produces sustained curative expression related significantly to integrated AAV in the absence of clinical toxicity, supporting its therapeutic potential for early-onset monogenic disorders.-Chan, J. K. Y., Gil-Farina I., Johana, N., Rosales, C., Tan, Y. W., Ceiler, J., Mcintosh, J., Ogden, B., Waddington, S. N., Schmidt, M., Biswas, A., Choolani, M., Nathwani, A. C., Mattar, C. N. Z. Therapeutic expression of human clotting factors IX and X following adeno-associated viral vector-mediated intrauterine gene transfer in early-gestation fetal macaques
Cloud-scale Radio Surveys of Star Formation and Feedback in Triangulum Galaxy M 33: VLA Observations
Studying the interplay between massive star formation and the interstellar medium (ISM) is paramount to understand the evolution of galaxies. Radio continuum (RC) emission serves as an extinction-free tracer of both massive star formation and the energetic components of the interstellar medium. We present a multi-band radio continuum survey of the local group galaxy M 33 down to ~30 pc linear resolution observed with the Karl G. Jansky Very Large Array (VLA). We calibrate the star-formation rate surface density and investigate the impact of diffuse emission on this calibration using a structural decomposition. Separating the thermal and nonthermal emission components, the correlation between different phases of the interstellar medium and the impact of massive star formation are also investigated. Radio sources with sizes <~ 200 pc constitute about 36% (46%) of the total RC emission at 1.5 GHz (6.3 GHz) in the inner 18' x 18' (or 4kpc x 4kpc) disk of M 33. The nonthermal spectral index becomes flatter with increasing star-formation rate surface density, indicating the escape of cosmic ray electrons {from their birth places}. The magnetic field strength also increases with star-formation rate following a bi-modal relation, indicating that the small-scale turbulent dynamo acts more efficiently at higher luminosities and star-formation rates. Although the correlations are tighter in star-forming regions, the nonthermal emission is correlated also with the more quiescent molecular gas in the ISM. An almost linear molecular star-formation law exists in M 33 when excluding diffuse structures. Massive star formation amplifies the magnetic field and increases the number of high-energy cosmic ray electrons, which can help the onset of winds and outflows
Cartilage oligomeric matrix protein in idiopathic pulmonary fibrosis
Idiopathic pulmonary fibrosis (IPF) is a progressive and life threatening disease with median survival of 2.5-3 years. The IPF lung is characterized by abnormal lung remodeling, epithelial cell hyperplasia, myofibroblast foci formation, and extracellular matrix deposition. Analysis of gene expression microarray data revealed that cartilage oligomeric matrix protein (COMP), a non-collagenous extracellular matrix protein is among the most significantly up-regulated genes (Fold change 13, p-value <0.05) in IPF lungs. This finding was confirmed at the mRNA level by nCounter® expression analysis in additional 115 IPF lungs and 154 control lungs as well as at the protein level by western blot analysis. Immunohistochemical analysis revealed that COMP was expressed in dense fibrotic regions of IPF lungs and co-localized with vimentin and around pSMAD3 expressing cells. Stimulation of normal human lung fibroblasts with TGF-β1 induced an increase in COMP mRNA and protein expression. Silencing COMP in normal human lung fibroblasts significantly inhibited cell proliferation and negatively impacted the effects of TGF-β1 on COL1A1 and PAI1. COMP protein concentration measured by ELISA assay was significantly increased in serum of IPF patients compared to controls. Analysis of serum COMP concentrations in 23 patients who had prospective blood draws revealed that COMP levels increased in a time dependent fashion and correlated with declines in force vital capacity (FVC). Taken together, our results should encourage more research into the potential use of COMP as a biomarker for disease activity and TGF-β1 activity in patients with IPF. Hence, studies that explore modalities that affect COMP expression, alleviate extracellular matrix rigidity and lung restriction in IPF and interfere with the amplification of TGF-β1 signaling should be persuaded. © 2013 Vuga et al
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
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