1,173 research outputs found
WiggleZ Dark Energy Survey: Cosmological neutrino mass constraint from blue high-redshift galaxies
The absolute neutrino mass scale is currently unknown, but can be constrained by cosmology. The WiggleZ high redshift, star-forming, and blue galaxy sample offers a complementary data set to previous surveys for performing these measurements, with potentially different systematics from nonlinear structure formation, redshift-space distortions, and galaxy bias. We obtain a limit of ∑m_ν<0.60  eV (95% confidence) for WiggleZ+Wilkinson Microwave Anisotropy Probe. Combining with priors on the Hubble parameter and the baryon acoustic oscillation scale gives ∑m_ν<0.29  eV, which is the strongest neutrino mass constraint derived from spectroscopic galaxy redshift surveys
The primordial deuterium abundance at z = 2.504 from a high signal-to-noise spectrum of Q1009+2956
The spectrum of the quasar Q1009+2956 has been observed
extensively on the Keck telescope. The Lyman limit absorption system was previously used to measure D/H by Burles & Tytler using a
spectrum with signal to noise approximately 60 per pixel in the continuum near
Ly {\alpha} at . The larger dataset now available combines
to form an exceptionally high signal to noise spectrum, around 147 per pixel.
Several heavy element absorption lines are detected in this LLS, providing
strong constraints on the kinematic structure. We explore a suite of absorption
system models and find that the deuterium feature is likely to be contaminated
by weak interloping Ly {\alpha} absorption from a low column density H I cloud,
reducing the expected D/H precision. We find D/H =
for this system. Combining this new
measurement with others from the literature and applying the method of Least
Trimmed Squares to a statistical sample of 15 D/H measurements results in a
"reliable" sample of 13 values. This sample yields a primordial deuterium
abundance of (D/H). The
corresponding mean baryonic density of the Universe is . The quasar absorption data is of the same precision as, and
marginally inconsistent with, the 2015 CMB Planck (TT+lowP+lensing)
measurement, . Further quasar and more
precise nuclear data are required to establish whether this is a random
fluctuation.Comment: accepted by MNRAS, 18 pages, 12 figures, 6 table
Common and variant properties of intermediate filament proteins from lower chordates and vertebrates; two proteins from the tunicate Styela and the identification of a type III homologue.
2021 National Farm to Early Care and Education Survey: Farm to Early Care and Education Continues to Foster Bright Futures for Children and Communities - Brief Compilation
The resource documents collection highlights key findings from a national survey of ECE providers regarding the implementation of farm-to-ECE programs. Findings also include the challenges identified by ECE providers that are informative for the field in dissemination and advocacy. Providers can also use the information to support their efforts and seek funding
Farm to early care and education continues to foster bright futures for children and communities: 2021 National farm to early care and education factsheet
The resource documents highlight key findings from a national survey of ECE providers regarding the implementation of farm-to-ECE programs. Findings also include the challenges identified by ECE providers that are informative for the field in dissemination and advocacy. Providers can also use the information to support their efforts and seek funding
Thissavros Hydropower Plant Managing Geotechnical Problems in the Construction
The Thissavros hydropower and pumped storage project on the Nestos river in northern Greece involved construction of a 172 m high rockfill dam and an underground power house with 300 MW installed capacity. Bedrock at the site consists of gneiss with complex geological structure and complicated hydrogeological conditions. On the right abutment, the dam partially rests on a large landslide and the toe of another large landslide extends into the plunge pool from the left bank. Initial excavations activated the dormant slides. Unloading, buttressing and drainage successfully stabilized the landslides. Core material for the dam is a silty sand and required special precautions in design and construction. Starting with an extremely rapid reservoir filling the dam has performed highly satisfactorily. The power house had to be excavated in a relatively unfavorable geological orientation but application of structural discontinuity analysis avoided wedge failures
Human Agency in AI Configurations Supporting Organizational Decision-making
The integration of human intelligence with Artificial Intelligence (AI) is becoming increasingly essential for leveraging benefits in organizational decision-making. This necessitates to understand human-AI collaboration configurations for managing collaborative intelligence. However, existing literature on Human-AI collaboration lacks structure and is fragmented regarding what exactly human intelligence (HI) contributes to AI collaboration and how AI systems can be configured in the decision-making process. This paper undertakes an organizing literature review to consolidate insights from existing literature. We identify six types of human agency as involved in collaborative intelligence and synthesize the findings into six Human-AI collaborative configurations explained by a matrix framework. By illuminating the complexities of Human-AI collaboration, the framework sheds light on the need for a nuanced understanding of the imbricating roles of HI and AI in decision-making, with important implications for the design and implementation of AI systems for organizational decision-making
Homogeneous bubble nucleation limit of mercury under the normal working conditions of the planned European Spallation Source
In spallation neutron sources, liquid mercury is the subject of big thermal
and pressure shocks, upon adsorbing the proton beam. These changes can cause
unstable bubbles in the liquid, which can damage the structural material. While
there are methods to deal with the pressure shock, the local temperature shock
cannot be avoided. In our paper we calculated the work of the critical cluster
formation (i.e. for mercury micro-bubbles) together with the rate of their
formation (nucleation rate). It is shown that the homogeneous nucleation rates
are very low even after adsorbing several proton pulses, therefore the
probability of temperature induced homogeneous bubble nucleation is negligible.Comment: 22 Pages, 11 figures, one of them is colour, we plan to publish it in
Eur. Phys. J.
Primordial deuterium abundance at z=2.504 towards Q1009+2956
The z_abs = 2.504 Lyman Limit absorption system (LLS) towards Q1009+2956 has
previously been used to estimate the primordial deuterium abundance. Since the
initial measurement by Burles & Tytler, this quasar has been observed
extensively with the Keck telescope, providing a substantial increase in
signal-to-noise (from 60 to 147 at continuum level of Ly-alpha at z_abs=2.504).
We explore a set of different models for the absorption system and find that
the deuterium feature is contaminated by Ly-alpha absorption from a low column
density H I cloud. This significantly limits precision to which one can
estimate the D/H ratio in this LLS. Our final result for this system D/H
=2.48^{+0.41}_{-0.35}*10^{-5} has the same relative uncertainty of 17% as the
previous estimate by Burles & Tytler despite the far higher signal-to-noise of
our dataset. A weighted mean of 13 D/H measurements available in the literature
(including our result) gives the primordial deuterium abundance of (D/H)_p =
(2.545 +/- 0.025)*10^{-5} and the corresponding baryon density of the Universe
of Omega_b h^2 = 0.02174 +/- 0.00025 marginally inconsistent with the 2015
Planck CMB data.Comment: 7 pages, 3 figures, conference proceedings from PhysicA.SPb 201
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