10,374 research outputs found
Spatial genetic structure in the saddled sea bream (Oblada melanura [Linnaeus, 1758]) suggests multi-scaled patterns of connectivity between protected and unprotected areas in the Western Mediterranean Sea
Marine protected areas (MPAs) and networks of MPAs are advocated worldwide for the achievement of marine conservation objectives. Although the knowledge about population connectivity is considered fundamental for the optimal design of MPAs and networks, the amount of information available for the Mediterranean Sea is currently scarce. We investigated the genetic structure of the saddled sea bream ( Oblada melanura) and the level of genetic connectivity between protected and unprotected locations, using a set of 11 microsatellite loci. Spatial patterns of population differentiation were assessed locally (50-100 km) and regionally (500-1000 km), considering three MPAs of the Western Mediterranean Sea. All values of genetic differentiation between locations (Fst and Jost's D) were non-significant after Bonferroni correction, indicating that, at a relatively small spatial scale, protected locations were in general well connected with non-protected ones. On the other hand, at the regional scale, discriminant analysis of principal components revealed the presence of a subtle pattern of genetic heterogeneity that reflects the geography and the main oceanographic features (currents and barriers) of the study area. This genetic pattern could be a consequence of different processes acting at different spatial and temporal scales among which the presence of admixed populations, large population sizes and species dispersal capacity, could play a major role. These outcomes can have important implications for the conservation biology and fishery management of the saddled sea bream and provide useful information for genetic population studies of other coastal fishes in the Western Mediterranean Sea
In-Trail Procedure (ITP) Algorithm Design
The primary objective of this document is to provide a detailed description of the In-Trail Procedure (ITP) algorithm, which is part of the Airborne Traffic Situational Awareness In-Trail Procedure (ATSA-ITP) application. To this end, the document presents a high level description of the ITP Algorithm and a prototype implementation of this algorithm in the programming language C
Cosmic-ray propagation properties for an origin in SNRs
We have studied the impact of cosmic-ray acceleration in SNR on the spectra
of cosmic-ray nuclei in the Galaxy using a series expansion of the propagation
equation, which allows us to use analytical solutions for part of the problem
and an efficient numerical treatment of the remaining equations and thus
accurately describes the cosmic-ray propagation on small scales around their
sources in three spatial dimensions and time. We found strong variations of the
cosmic-ray nuclei flux by typically 20% with occasional spikes of much higher
amplitude, but only minor changes in the spectral distribution. The locally
measured spectra of primary cosmic rays fit well into the obtained range of
possible spectra. We further showed that the spectra of the secondary element
Boron show almost no variations, so that the above findings also imply
significant fluctuations of the Boron-to-Carbon ratio. Therefore the commonly
used method of determining CR propagation parameters by fitting
secondary-to-primary ratios appears flawed on account of the variations that
these ratios would show throughout the Galaxy.Comment: Accepted for publication in Ap
Heparan sulfate disaccharide measurement from biological samples using pre-column derivatization, UPLC-MS and single ion monitoring
Glycosaminoglycans are a heterogeneous family of linear polysaccharides comprised of repeating disaccharide subunits that mediate many effects at the cellular level. There is increasing evidence that the nature of these effects is determined by differences in disaccharide composition. However, the determination of GAG disaccharide composition in biological samples remains challenging and time-consuming. We have developed a method that uses derivatization and selected ion recording and RP-UPLCMS resulting in rapid separation and quantification of twelve heparin/heparin sulfate disaccharides from 5 ÎŒg GAG. Limits of detection and quantitation were 0.02â0.15 and 0.07â0.31 ÎŒg/ml respectively. We have applied this method to the novel analysis of disaccharide levels extracted from heparan sulfate and human cancer cell lines. Heparan sulfate disaccharides extracted from biological samples following actinase and heparinase incubation and derivatized using reductive amination with 2-aminoacridone. Derivatized disaccharides were analyzed used UPLC-MS with single ion monitoring. Eight HS disaccharide subunits were separated and quantified from HS and cell lines in eleven minutes per sample. In all samples the most abundant subunits present were the unsulfated ÎUA-GlcNAc, ÎUA-GlcNAc,6S and ÎUA,2S-GlcNS,6S. There was considerable variation in the proportions and concentrations of disaccharides between different cell lines. Further studies are needed to examine the significance of these differences
How to hide a secret direction
We present a procedure to share a secret spatial direction in the absence of
a common reference frame using a multipartite quantum state. The procedure
guarantees that the parties can determine the direction if they perform joint
measurements on the state, but fail to do so if they restrict themselves to
local operations and classical communication (LOCC). We calculate the fidelity
for joint measurements, give bounds on the fidelity achievable by LOCC, and
prove that there is a non-vanishing gap between the two of them, even in the
limit of infinitely many copies. The robustness of the procedure under particle
loss is also studied. As a by-product we find bounds on the probability of
discriminating by LOCC between the invariant subspaces of total angular
momentum N/2 and N/2-1 in a system of N elementary spins.Comment: 4 pages, 1 figur
Supergalactic winds driven by multiple superstar clusters
We present two dimensional hydrodynamic calculations of free expanding
supergalactic winds, taking into consideration strong radiative cooling. Our
main premise is that supergalactic winds are powered by collections of
superstar clusters. Every individual superstar cluster is a source of a high
metallicity radiative supersonic outflow (paper I, 2003, ApJ, 590, 791). The
interaction of winds from neighboring knots of star formation is shown to lead
to a collection of stationary oblique shocks and crossing shocks, able to
structure the general outflow into a network of dense and cold, kpc long
filaments that originate near the base of the outflow. The shocks also lead to
extended regions of diffuse soft X-ray emission and furthermore, to channel the
outflow with a high degree of collimation into the intergalactic medium.Comment: 10 pages, 5 figures, Accepted for publication in The Astrophysical
Journa
The ANMLite Language and Logic for Specifying Planning Problems
We present the basic concepts of the ANMLite planning language. We discuss various aspects of specifying a plan in terms of constraints and checking the existence of a solution with the help of a model checker. The constructs of the ANMLite language have been kept as simple as possible in order to reduce complexity and simplify the verification problem. We illustrate the language with a specification of the space shuttle crew activity model that was constructed under the Spacecraft Autonomy for Vehicles and Habitats (SAVH) project. The main purpose of this study was to explore the implications of choosing a robust logic behind the specification of constraints, rather than simply proposing a new planning language
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