8,723 research outputs found
The parameters of Menzerath-Altmann law in genomes
The relationship between the size of the whole and the size of the parts in
language and music is known to follow Menzerath-Altmann law at many levels of
description (morphemes, words, sentences...). Qualitatively, the law states
that larger the whole, the smaller its parts, e.g., the longer a word (in
syllables) the shorter its syllables (in letters or phonemes). This patterning
has also been found in genomes: the longer a genome (in chromosomes), the
shorter its chromosomes (in base pairs). However, it has been argued recently
that mean chromosome length is trivially a pure power function of chromosome
number with an exponent of -1. The functional dependency between mean
chromosome size and chromosome number in groups of organisms from three
different kingdoms is studied. The fit of a pure power function yields
exponents between -1.6 and 0.1. It is shown that an exponent of -1 is unlikely
for fungi, gymnosperm plants, insects, reptiles, ray-finned fishes and
amphibians. Even when the exponent is very close to -1, adding an exponential
component is able to yield a better fit with regard to a pure power-law in
plants, mammals, ray-finned fishes and amphibians. The parameters of
Menzerath-Altmann law in genomes deviate significantly from a power law with a
-1 exponent with the exception of birds and cartilaginous fishes.Comment: Typos and little inaccuracies corrected. Title and references updated
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An equatorial ultra iron-poor star identified in BOSS
We report the discovery of SDSS J131326.89-001941.4, an ultra iron-poor red
giant star ([Fe/H] ~ -4.3) with a very high carbon abundance ([C/Fe]~ +2.5).
This object is the fifth star in this rare class, and the combination of a
fairly low effective temperature (Teff ~ 5300 K), which enhances line
absorption, with its brightness (g=16.9), makes it possible to measure the
abundances of calcium, carbon and iron using a low-resolution spectrum from the
Sloan Digital Sky Survey. We examine the carbon and iron abundance ratios in
this star and other similar objects in the light of predicted yields from
metal-free massive stars, and conclude that they are consistent. By way of
comparison, stars with similarly low iron abundances but lower carbon-to-iron
ratios deviate from the theoretical predictions.Comment: 6 pages, 4 figures, accepted for publication in A&
Recent evolution of erosive landforms induced by urban-touristic impact inside an arid transgressive dune system
Functional variants in the LRRK2 gene confer shared effects on risk for Crohn\u27s disease and Parkinson\u27s disease
The role of seagrass meadows in the coastal trapping of litter
The accelerated discard and mismanagement of human-made products are resulting in the continued input of litter into the oceans. Models and field observations show how floating litter can accumulate in remote areas throughout the global ocean, but far less is known about the non-floating litter fraction. Seagrass meadows play an important role in the sediment and natural-debris dynamics, and likely also in the storage and processing of non-floating litter. In this work, non-floating litter was studied across six Posidonia oceanica meadows. Litter accumulated mainly around the landside edge of the meadow. The outer margin of the edge predominantly trapped macro-litter, whilst microplastics accumulated mainly along the inner margin. On average, macro-litter concentrations increased 3-fold after heavy rainfall. Retention of non-floating litter by coastal meadows facilitates the recurrent landward-seaward conveyance of the easily-transportable litter (mainly plastic items) and its fragmentation before it is buried or transferred to deeper areas.peer-reviewe
1-Ethyl-2,3-dimethylimidazolium paramagnetic ionic liquids with 3D magnetic ordering in its solid state: synthesis, structure and magneto-structural correlations
Financial support from the Spanish Ministerio de Ciencia e
Innovaci´on (Projects MAT2011-27573-C04) and Becas Iberoamericas
J´ovenes Profesores Investigadores, 2015, Santander
Universidades is acknowledged. The authors gratefully acknowledge
the MALTA Consolider Ingenio 2010 (Ref. CSD2007-00045).
IH acknowledges funding from the EU FP7 (Marie Curie-CIG
303535)
Ventricular arrhythmias in patients with functional mitral regurgitation and implantable cardiac devices: implications of mitral valve repair with Mitraclip
Background: Limited information has been reported regarding the impact of percutaneous mitral valve repair (PMVR) on ventricular arrhythmic (VA) burden. The aim of this study was to address the incidence of VA and appropriate antitachycardia implantable cardiac defibrillator (ICD) therapies before and after PMVR. Methods: We retrospectively analyzed all consecutive patients with heart failure with reduce left ventricular ejection fraction (LVEF), functional mitral regurgitation (FMR) grade 3+ or 4+ and an active ICD or cardiac resynchronizer who underwent PMVR in any of the eleven recruiting centers. Only patients with complete available device VA monitoring from one-year before to one year after PMVR were included. Baseline clinical and echocardiographic characteristics were collected before PMVR and at 12-months follow-up. Results: Ninety-three patients (68.2+/-10.9 years old, male 88.2%) were enrolled. PMVR was successfully performed in all patients and device success at discharge was 91.4%. At 12-month follow-up, we observed a significant reduction in mitral regurgitation severity, NT-proBNP and prevalence of severe pulmonary hypertension and severe kidney disease. Patients also referred a significant improvement in NYHA functional class and showed a non-significant trend to reserve left ventricular remodeling. After PMVR a significant decrease in the incidence of non-sustained ventricular tachycardia (VT) (5.0+/-17.8 vs. 2.7+/-13.5, P=0.002), sustained VT or ventricular fibrillation (0.9+/-2.5 vs. 0.5+/-2.9, P=0.012) and ICD antitachycardia therapies (2.5+/-12.0 vs. 0.9+/-5.0, P=0.033) were observed. Conclusions: PMVR was related to a reduction in arrhythmic burden and ICD therapies in our cohort
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