Metagenomic studies characterize both the composition and diversity of uncultured viral and microbial communities. BLAST-based comparisons have typically been used for such analyses; however, ...sampling biases, high percentages of unknown sequences, and the use of arbitrary thresholds to find significant similarities can decrease the accuracy and validity of estimates. Here, we present Genome relative Abundance and Average Size (GAAS), a complete software package that provides improved estimates of community composition and average genome length for metagenomes in both textual and graphical formats. GAAS implements a novel methodology to control for sampling bias via length normalization, to adjust for multiple BLAST similarities by similarity weighting, and to select significant similarities using relative alignment lengths. In benchmark tests, the GAAS method was robust to both high percentages of unknown sequences and to variations in metagenomic sequence read lengths. Re-analysis of the Sargasso Sea virome using GAAS indicated that standard methodologies for metagenomic analysis may dramatically underestimate the abundance and importance of organisms with small genomes in environmental systems. Using GAAS, we conducted a meta-analysis of microbial and viral average genome lengths in over 150 metagenomes from four biomes to determine whether genome lengths vary consistently between and within biomes, and between microbial and viral communities from the same environment. Significant differences between biomes and within aquatic sub-biomes (oceans, hypersaline systems, freshwater, and microbialites) suggested that average genome length is a fundamental property of environments driven by factors at the sub-biome level. The behavior of paired viral and microbial metagenomes from the same environment indicated that microbial and viral average genome sizes are independent of each other, but indicative of community responses to stressors and environmental conditions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Strategic entrepreneurship Audretsch, David B; Ireland, R Duane; Covin, Jeffrey G ...
Entrepreneurship theory and practice,
01/2009, Letnik:
33, Številka:
1
Journal Article
The next generation of space-based observatories will characterize the atmospheres of low-mass, temperate exoplanets with the direct-imaging technique. This will be a major step forward in our ...understanding of exoplanet diversity and the prevalence of potentially habitable conditions beyond the Earth. We compute a list of currently known exoplanets detectable with the mid-infrared Large Interferometer For Exoplanets (LIFE) in thermal emission. We also compute the list of known exoplanets accessible to a notional design of the Habitable Worlds Observatory (HWO), observing in reflected starlight. With a pre-existing method, we processed the NASA Exoplanet Archive and computed orbital realizations for each known exoplanet. We derived their mass, radius, equilibrium temperature, and planet-star angular separation. We used the LIFEsim simulator to compute the integration time (\(t_{int}\)) required to detect each planet with LIFE. A planet is considered detectable if a broadband signal-to-noise ratio \(S/N\)=7 is achieved over the spectral range \(4-18.5\mu\)m in \(t_{int}\leq\)100 hours. We tested whether the planet is accessible to HWO in reflected starlight based on its notional inner and outer working angles, and minimum planet-to-star contrast. LIFE's reference configuration (four 2-m telescopes with 5% throughput and a nulling baseline between 10-100 m) can detect 212 known planets within 20 pc. Of these, 55 are also accessible to HWO in reflected starlight, offering a unique opportunity for synergies in atmospheric characterization. LIFE can also detect 32 known transiting exoplanets. Furthermore, 38 LIFE-detectable planets orbit in the habitable zone, of which 13 with \(M_p<5M_\oplus\) and 8 with \(5M_\oplus<M_p<10M_\oplus\). LIFE already has enough targets to perform ground-breaking analyses of low-mass, habitable-zone exoplanets, a fraction of which will also be accessible to other instruments.
The isolated globule B335 contains a single, low luminosity Class 0 protostar
associated with a bipolar nebula and outflow system seen nearly perpendicular
to its axis. We observed the innermost ...regions of this outflow as part of
JWST/NIRCam GTO program 1187, primarily intended for wide-field slitless
spectroscopy of background stars behind the globule. We find a system of
expanding shock fronts with kinematic ages of only a few decades emerging
symmetrically from the position of the embedded protostar, which is not
directly detected at NIRCam wavelengths. The innermost and youngest of the
shock fronts studied here shows strong emission from CO. The next older shock
front shows less CO and the third shock front shows only H_2 emission in our
data. This third and most distant of these inner shock fronts shows substantial
evolution of its shape since it was last observed with high spatial resolution
in 1996 with Keck/NIRC. This may be evidence of a faster internal shock
catching up with a slower one and of the two shocks merging.
Observations of debris disks offer important insights into the formation and evolution of planetary systems. Though M dwarfs make up approximately 80% of nearby stars, very few M-dwarf debris disks ...have been studied in detail -- making it unclear how or if the information gleaned from studying debris disks around more massive stars extends to the more abundant M dwarf systems. We report the first scattered-light detection of the debris disk around the M4 star Fomalhaut C using JWST's Near Infrared Camera (NIRCam; 3.6\(~\mu\)m and 4.4\(~\mu\)m). This result adds to the prior sample of only four M-dwarf debris disks with detections in scattered light, and marks the latest spectral type and oldest star among them. The size and orientation of the disk in these data are generally consistent with the prior ALMA sub-mm detection. Though no companions are identified, these data provide strong constraints on their presence -- with sensitivity sufficient to recover sub-Saturn mass objects in the vicinity of the disk. This result illustrates the unique capability of JWST for uncovering elusive M-dwarf debris disks in scattered light, and lays the groundwork for deeper studies of such objects in the 2--5\(~\mu\)m regime.
Optimal individualized treatment decision-making has improved health outcomes in recent years. The value function is commonly used to evaluate the goodness of an individualized treatment decision ...rule. Despite recent advances, comparing value functions between different treatment decision rules or constructing confidence intervals around value functions remains difficult. We propose a t-test based method applied to a test set that generates valid p-values to compare value functions between a given pair of treatment decision rules when some of the data are missing. We demonstrate the ease in use of this method and evaluate its performance via simulation studies and apply it to the China Health and Nutrition Survey data.
IntroductionLeft ventricular (LV) delay, as measured by the QLV interval, at the LV pacing site predicts a number of outcomes with CRT including the magnitude of reverse remodeling. It also ...identifies a subgroup of patients (pts) who benefit from atrioventricular optimization (AVO). Whether interventricular delay at CRT pacing sites is associated with better CRT response is unknown.HypothesisPacing at sites of long interventricular delay, as measured by RV-LV duration, increases LV reverse remodeling and the effectiveness of AVO.MethodsThis substudy of SMART-AV included 419 pts who were randomized to either an electrogram (EGM) based AVO (SmartDelay) or nominal AV delay (120 ms). The RV-LV interval was measured from the peaks of RV and LV EGMs in sinus rhythm. CRT response was defined prospectively as a > 15% reduction in left ventricular end-systolic volume (LVESV) from implant to 6 months.ResultsThe cohort was 66% male, with a mean age of 66±11 years and LV ejection fraction of 28±9%. When grouped by quartiles based on interventricular delay, there was a progressive increase in the magnitude of change in LVESV and CRT response rate for the entire cohort (p’s < 0.01). AVO reduced LVESV progressively more than fixed AV delay as RV-LV prolonged (interaction p = 0.069), with the largest reduction in the longest RV-LV quartile (p=0.011, figure). This difference remained significant (p=0.032) after adjusting for baseline covariates including etiology of HF, LBBB, gender, NYHA, QRS duration, age and baseline LVESV. Pts in the longest RV-LV quartile had 2.8 times greater odds of CRT response with AVO compared to fixed AV delay (p = 0.07).ConclusionBaseline interventricular electrical dyssynchrony, as measured by RV-LV duration, predicts CRT reverse remodeling response. At long RV-LV intervals, AVO can increase the likelihood of a reverse remodeling with CRT. AVO and RV-LV optimized lead locations may work synergistically to maximize CRT response.
MWC 758 is a young star hosting a spiral protoplanetary disk. The spirals are
likely companion-driven, and two previously-identified candidate companions
have been identified -- one at the end the ...Southern spiral arm at ~0.6 arcsec,
and one interior to the gap at ~0.1 arcsec. With JWST/NIRCam, we provide new
images of the disk and constraints on planets exterior to ~1". We detect the
two-armed spiral disk, a known background star, and a spatially resolved
background galaxy, but no clear companions. The candidates that have been
reported are at separations that are not probed by our data with sensitivity
sufficient to detect them -- nevertheless, these observations place new limits
on companions down to ~2 Jupiter-masses at ~150 au and ~0.5 Jupiter masses at
~600 au. Owing to the unprecedented sensitivity of JWST and youth of the
target, these are among the deepest mass-detection limits yet obtained through
direct imaging observations, and provide new insights into the system's
dynamical nature.
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