871 research outputs found
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Seed dispersers help plants to escape global warming
Plants are shifting their ranges towards higher elevations in response to global warming, yet such shifts are occurring at a rate slower than is needed to keep pace with a rapidly changing climate. There is, however, an almost complete lack of knowledge on seed dispersal across altitude, a key process to understand what constrains climate-driven range shifts. Here, we report the first direct empirical evidence on altitudinal seed dispersal mediated by two common frugivorous mammals: the red fox Vulpes vulpes and the pine marten Martes martes. We conducted a three-year (bait-marking) experiment in a mountainous region of Spain. We offered experimental fruits containing colour-coded seed mimics at feeding stations that simulated source trees. The colour codes allowed us to identify the exact origin of seed mimics found later in mammal scats. Nearly half (47%) of the dispersal events occurred towards higher elevations, despite only ca 25% of the study area being above the average altitude of the feeding stations (1344 m). Seeds dispersed uphill gained an average of 106 m (median = 111 m) and a maximum of 288 m, greatly exceeding the estimated requirements to escape warming (35.4 m per decade). Yet, foxes mediated much more uphill seed dispersal than martens (57% and 26% of dispersal events, respectively), which can be explained by between-disperser differences in home range size and habitat specificity. Dispersers with larger home ranges move farther and potentially disperse more seeds to higher altitudes, while habitat generalism is necessary to transport seeds above vegetation belts delimiting contrasting habitat types. We discuss how both traits (home range size and habitat specificity) can be used to infer altitudinal seed dispersal across disperser species and mountainous landscapes.This study was funded by the Galician Regional Government (project PGIDIT 05RFO 20001 PR). JPGV 310 was supported by an Individual Fellowship from the Marie Sklodowska-Curie Actions (H2020-MSCA-IF-2014-656572: MOBILELINKS). JVLB was supported by a âJuan de la 312 Ciervaâ research contract (JCI-2012-13066) from the Spanish Ministry of Economy and Competitiveness
Geographic constraints on social network groups
Social groups are fundamental building blocks of human societies. While our
social interactions have always been constrained by geography, it has been
impossible, due to practical difficulties, to evaluate the nature of this
restriction on social group structure. We construct a social network of
individuals whose most frequent geographical locations are also known. We also
classify the individuals into groups according to a community detection
algorithm. We study the variation of geographical span for social groups of
varying sizes, and explore the relationship between topological positions and
geographic positions of their members. We find that small social groups are
geographically very tight, but become much more clumped when the group size
exceeds about 30 members. Also, we find no correlation between the topological
positions and geographic positions of individuals within network communities.
These results suggest that spreading processes face distinct structural and
spatial constraints.Comment: 10 pages, 5 figure
Utility of Gene Panels for the Diagnosis of Inborn Errors of Metabolism in a Metabolic Reference Center
Next-generation sequencing (NGS) technologies have been proposed as a first-line test for the diagnosis of inborn errors of metabolism (IEM), a group of genetically heterogeneous disorders with overlapping or nonspecific phenotypes. Over a 3-year period, we prospectively analyzed 311 pediatric patients with a suspected IEM using four targeted gene panels. The rate of positive diagnosis was 61.86% for intermediary metabolism defects, 32.84% for complex molecular defects, 19% for hypoglycemic/hyperglycemic events, and 17% for mitochondrial diseases, and a conclusive molecular diagnosis was established in 2-4 weeks. Forty-one patients for whom negative results were obtained with the mitochondrial diseases panel underwent subsequent analyses using the NeuroSeq panel, which groups all genes from the individual panels together with genes associated with neurological disorders (1870 genes in total). This achieved a diagnostic rate of 32%. We next evaluated the utility of a tool, Phenomizer, for differential diagnosis, and established a correlation between phenotype and molecular findings in 39.3% of patients. Finally, we evaluated the mutational architecture of the genes analyzed by determining z-scores, loss-of-function observed/expected upper bound fraction (LOEUF), and haploinsufficiency (HI) scores. In summary, targeted gene panels for specific groups of IEMs enabled rapid and effective diagnosis, which is critical for the therapeutic management of IEM patients.info:eu-repo/semantics/publishedVersio
Accurate masses and radii of normal stars: modern results and applications
This paper presents and discusses a critical compilation of accurate,
fundamental determinations of stellar masses and radii. We have identified 95
detached binary systems containing 190 stars (94 eclipsing systems, and alpha
Centauri) that satisfy our criterion that the mass and radius of both stars be
known to 3% or better. To these we add interstellar reddening, effective
temperature, metal abundance, rotational velocity and apsidal motion
determinations when available, and we compute a number of other physical
parameters, notably luminosity and distance. We discuss the use of this
information for testing models of stellar evolution. The amount and quality of
the data also allow us to analyse the tidal evolution of the systems in
considerable depth, testing prescriptions of rotational synchronisation and
orbital circularisation in greater detail than possible before. The new data
also enable us to derive empirical calibrations of M and R for single (post-)
main-sequence stars above 0.6 M(Sun). Simple, polynomial functions of T(eff),
log g and [Fe/H] yield M and R with errors of 6% and 3%, respectively.
Excellent agreement is found with independent determinations for host stars of
transiting extrasolar planets, and good agreement with determinations of M and
R from stellar models as constrained by trigonometric parallaxes and
spectroscopic values of T(eff) and [Fe/H]. Finally, we list a set of 23
interferometric binaries with masses known to better than 3%, but without
fundamental radius determinations (except alpha Aur). We discuss the prospects
for improving these and other stellar parameters in the near future.Comment: 56 pages including figures and tables. To appear in The Astronomy and
Astrophysics Review. Ascii versions of the tables will appear in the online
version of the articl
Bench-to-bedside review : targeting antioxidants to mitochondria in sepsis
Peer reviewedPublisher PD
A New Digital Preoperative Planning Method for Total Hip Arthroplasties
Preoperative templating is an important part of a THA. The ability to accurately determine magnification of the hip on the radiograph and apply identical magnification to the radiograph and template will improve accuracy of preoperative templating of THA. We designed a templating method using a new way of determining the hip magnification with a linear relationship between magnification of the hip and the reference object on top of the pubis symphysis; the relationship was determined on 50 radiographs. We then compared our method with two other templating methods: an analog method assuming an average hip magnification of 15% and a digital method determining the hip magnification with a one-to-one relationship between the reference object and the hip. All methods were reproducible. Uniform undersizing occurred when templating with the digital method based on the one-to-one relationship; the analog method best predicted the implanted prosthesis size, closely followed by our new digital templating method; the new method will be particularly applicable for preoperative THA when analog methods are replaced by digital methods
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Demonstration of the event identification capabilities of the NEXT-White detector
In experiments searching for neutrinoless double-beta decay, the possibility of identifying the two emitted electrons is a powerful tool in rejecting background events and therefore improving the overall sensitivity of the experiment. In this paper we present the first measurement of the efficiency of a cut based on the different event signatures of double and single electron tracks, using the data of the NEXT-White detector, the first detector of the NEXT experiment operating underground. Using a 228Th calibration source to produce signal-like and background-like events with energies near 1.6 MeV, a signal efficiency of 71.6 ± 1.5 stat± 0.3 sys% for a background acceptance of 20.6 ± 0.4 stat± 0.3 sys% is found, in good agreement with Monte Carlo simulations. An extrapolation to the energy region of the neutrinoless double beta decay by means of Monte Carlo simulations is also carried out, and the results obtained show an improvement in background rejection over those obtained at lower energies. [Figure not available: see fulltext.
Factors affecting post-fire crown regeneration in cork oak (Quercus suber L.) trees
Cork oak (Quercus suber) forests are acknowledged
for their biodiversity and economic (mainly cork
production) values. WildWres are one of the main threats
contributing to cork oak decline in the Mediterranean
Basin, and one major question that managers face after Wre
in cork oak stands is whether the burned trees should be
coppiced or not. This decision can be based on the degree
of expected crown regeneration assessed immediately after
Wre. In this study we carried out a post-Wre assessment of
the degree of crown recovery in 858 trees being exploited
for cork production in southern Portugal, 1.5 years after a
wildWre. Using logistic regression, we modelled good or
poor crown recovery probability as a function of tree and
stand variables. The main variables inXuencing the likelihood
of good or poor crown regeneration were bark thickness,
charring height, aspect and tree diameter. We also
developed management models, including simpler but easier
to measure variables, which had a lower predictive
power but can be used to help managers to identify, immediately
after Wre, trees that will likely show good crown
regeneration, and trees that will likely die or show poor
regeneration (and thus, potential candidates for trunk
coppicin
Experimental evolution of sperm competitiveness in a mammal
<p>Abstract</p> <p>Background</p> <p>When females mate with multiple partners, sperm from rival males compete to fertilise the ova. Studies of experimental evolution have proven the selective action of sperm competition on male reproductive traits. However, while reproductive traits may evolve in response to sperm competition, this does not necessarily provide evidence that sperm competitive ability responds to selection. Indeed, a study of <it>Drosophila </it>failed to observe divergence in sperm competitive ability of males in lines selected for enhanced sperm offence and defence.</p> <p>Results</p> <p>Adopting the naturally polygamous house mouse (<it>Mus domesticus</it>) as our vertebrate model, we performed an experimental evolution study and observed genetic divergence in sperm quality; males from the polygamous selection lines produced ejaculates with increased sperm numbers and greater sperm motility compared to males from the monogamous lines. Here, after 12 generations of experimental evolution, we conducted competitive matings between males from lineages evolving under sperm competition and males from lineages subject to relaxed selection. We reduced variation in paternity arising from embryo mortality by genotyping embryos <it>in utero </it>at 14 days gestation. Our microsatellite data revealed a significant paternity bias toward males that evolved under the selective regime of sperm competition.</p> <p>Conclusion</p> <p>We provide evidence that the sperm competitiveness phenotype can respond to selection, and show that improved sperm quality translates to greater competitive fertilisation success in house mice.</p
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