1,069 research outputs found
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Chionactis occipitalis
Number of Pages: 12Integrative BiologyGeological Science
Recommended from our members
Chionactis palarostris
Number of Pages: 5Integrative BiologyGeological Science
Dissipative eigenvalue problems for a Sturm-Liouville operator with a singular potential
We present a study of optical signatures of salmon lice and the ability to distinguish them from a reference zooplankton species. This forms the basis for developing an instrument for detecting salmon lice in situ
First Stellar Abundances in the Dwarf Irregular Galaxy Sextans A
We present the abundance analyses of three isolated A-type supergiant stars
in the dwarf irregular galaxy Sextans A from high-resolution spectra the UVES
spectrograph at the VLT. Detailed model atmosphere analyses have been used to
determine the stellar atmospheric parameters and the elemental abundances of
the stars. The mean iron group abundance was determined from these three stars
to be [(FeII,CrII)/H]=-0.99+/-0.04+/-0.06. This is the first determination of
the present-day iron group abundances in Sextans A. These three stars now
represent the most metal-poor massive stars for which detailed abundance
analyses have been carried out. The mean stellar alpha element abundance was
determined from the alpha element magnesium as
[alpha(MgI)/H]=-1.09+/-0.02+/-0.19. This is in excellent agreement with the
nebular alpha element abundances as determined from oxygen in the H II regions.
These results are consistent from star-to-star with no significant spatial
variations over a length of 0.8 kpc in Sextans A. This supports the nebular
abundance studies of dwarf irregular galaxies, where homogeneous oxygen
abundances are found throughout, and argues against in situ enrichment. The
alpha/Fe abundance ratio is [alpha(MgI)/FeII,CrII]=-0.11+/-0.02+/-0.10, which
is consistent with the solar ratio. This is consistent with the results from
A-supergiant analyses in other Local Group dwarf irregular galaxies but in
stark contrast with the high [alpha/Fe] results from metal-poor stars in the
Galaxy, and is most clearly seen from these three stars in Sextans A because of
their lower metallicities. The low [alpha/Fe] ratios are consistent with the
slow chemical evolution expected for dwarf galaxies from analyses of their
stellar populations.Comment: 40 pages, 8 figures, accepted for publication in A
Pseudorapidity distributions of charged particles from Au+Au collisions at the maximum RHIC energy, Sqrt(s_NN) = 200 GeV
We present charged particle densities as a function of pseudorapidity and
collision centrality for the 197Au+197Au reaction at Sqrt{s_NN}=200 GeV. For
the 5% most central events we obtain dN_ch/deta(eta=0) = 625 +/- 55 and
N_ch(-4.7<= eta <= 4.7) = 4630+-370, i.e. 14% and 21% increases, respectively,
relative to Sqrt{s_NN}=130 GeV collisions. Charged-particle production per pair
of participant nucleons is found to increase from peripheral to central
collisions around mid-rapidity. These results constrain current models of
particle production at the highest RHIC energy.Comment: 4 pages, 5 figures; fixed fig. 5 caption; revised text and figures to
show corrected calculation of and ; final version accepted for
publicatio
Vegetation demographics in Earth System Models: A review of progress and priorities
Numerous current efforts seek to improve the representation of ecosystem ecology and vegetation demographic processes within Earth System Models (ESMs). These developments are widely viewed as an important step in developing greater realism in predictions of future ecosystem states and fluxes. Increased realism, however, leads to increased model complexity, with new features raising a suite of ecological questions that require empirical constraints. Here, we review the developments that permit the representation of plant demographics in ESMs, and identify issues raised by these developments that highlight important gaps in ecological understanding. These issues inevitably translate into uncertainty in model projections but also allow models to be applied to new processes and questions concerning the dynamics of real-world ecosystems. We argue that stronger and more innovative connections to data, across the range of scales considered, are required to address these gaps in understanding. The development of first-generation land surface models as a unifying framework for ecophysiological understanding stimulated much research into plant physiological traits and gas exchange. Constraining predictions at ecologically relevant spatial and temporal scales will require a similar investment of effort and intensified inter-disciplinary communication
Danish Foundation Models
Large language models, sometimes referred to as foundation models, have
transformed multiple fields of research. However, smaller languages risk
falling behind due to high training costs and small incentives for large
companies to train these models. To combat this, the Danish Foundation Models
project seeks to provide and maintain open, well-documented, and high-quality
foundation models for the Danish language. This is achieved through broad
cooperation with public and private institutions, to ensure high data quality
and applicability of the trained models. We present the motivation of the
project, the current status, and future perspectives.Comment: 4 pages, 2 table
Exponential distribution of long heart beat intervals during atrial fibrillation and their relevance for white noise behaviour in power spectrum
The statistical properties of heart beat intervals of 130 long-term surface
electrocardiogram recordings during atrial fibrillation (AF) are investigated.
We find that the distribution of interbeat intervals exhibits a characteristic
exponential tail, which is absent during sinus rhythm, as tested in a
corresponding control study with 72 healthy persons. The rate of the
exponential decay lies in the range 3-12 Hz and shows diurnal variations. It
equals, up to statistical uncertainties, the level of the previously uncovered
white noise part in the power spectrum, which is also characteristic for AF.
The overall statistical features can be described by decomposing the intervals
into two statistically independent times, where the first one is associated
with a correlated process with 1/f noise characteristics, while the second one
belongs to an uncorrelated process and is responsible for the exponential tail.
It is suggested to use the rate of the exponential decay as a further parameter
for a better classification of AF and for the medical diagnosis. The relevance
of the findings with respect to a general understanding of AF is pointed out
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