5,706 research outputs found
The rotational shear layer inside the early red-giant star KIC 4448777
We present the asteroseismic study of the early red-giant star KIC 4448777,
complementing and integrating a previous work (Di Mauro et al. 2016), aimed at
characterizing the dynamics of its interior by analyzing the overall set of
data collected by the {\it Kepler} satellite during the four years of its first
nominal mission. We adopted the Bayesian inference code DIAMOND (Corsaro \& De
Ridder 2014) for the peak bagging analysis and asteroseismic splitting
inversion methods to derive the internal rotational profile of the star. The
detection of new splittings of mixed modes, more concentrated in the very inner
part of the helium core, allowed us to reconstruct the angular velocity profile
deeper into the interior of the star and to disentangle the details better than
in Paper I: the helium core rotates almost rigidly about 6 times faster than
the convective envelope, while part of the hydrogen shell seems to rotate at a
constant velocity about 1.15 times lower than the He core. In particular, we
studied the internal shear layer between the fast-rotating radiative interior
and the slow convective zone and we found that it lies partially inside the
hydrogen shell above and extends across the core-envelope
boundary. Finally, we theoretically explored the possibility for the future to
sound the convective envelope in the red-giant stars and we concluded that the
inversion of a set of splittings with only low-harmonic degree , even
supposing a very large number of modes, will not allow to resolve the
rotational profile of this region in detail.Comment: accepted for publication on Ap
Caracterização físico-química e reológica de farinhas mistas instantâneas de arroz, milho e feijão por extrusão.
High Levels of Chromosomal Differentiation in Euchroma gigantea L. 1735 (Coleoptera, Buprestidae)
Euchroma giganteawas karyotypically studied using conventional staining, C-banding, silver nitrate staining and ribosomal fluorescent in situ hybridization (rDNA FISH). Broad wide autosomal polymorphism and a complex sex determination system were found in this beetle. Karyotype complements ranging from 2n = 32, X1X2X3Y1Y2Y3 to 2n = 36,X1X2X3Y1Y2Y3 were detected in the sample analyzed. Punctiform suernumerary chromosomes were present in the different karyotypes. The karyotypic evolution of Brazilian E. giganteamay have taken two directions, reduction in the diploid number of 2n = 36 to 24 through centric fusions or 2n = 24 to 36 due to chromosomal fissions. In addition, pericentric inversions were also involved. The complex multiple sex mechanism of this species seems to be old and well established since it is found in specimens from different populations. Small pericentromeric blocks of constitutive heterochromatin were located on the autosomes and terminal blocks were also found on some small pairs. The sex chromosomes showed larger constitutive heterochromatin blocks. Silver nitrate staining during prophase I of meiosis showed labeling of the sex chromosome chain. However, the rDNA sites could only be precisely determined by FISH, which permitted the identification of these ribosomal sites on chromosomes X1 and X2 of this species
Structural properties of crumpled cream layers
The cream layer is a complex heterogeneous material of biological origin
which forms spontaneously at the air-milk interface. Here, it is studied the
crumpling of a single cream layer packing under its own weight at room
temperature in three-dimensional space. The structure obtained in these
circumstances has low volume fraction and anomalous fractal dimensions. Direct
means and noninvasive NMR imaging technique are used to investigate the
internal and external structure of these systems.Comment: 9 pages, 4 figures, accepted in J. Phys. D: Appl. Phy
On Deciding Local Theory Extensions via E-matching
Satisfiability Modulo Theories (SMT) solvers incorporate decision procedures
for theories of data types that commonly occur in software. This makes them
important tools for automating verification problems. A limitation frequently
encountered is that verification problems are often not fully expressible in
the theories supported natively by the solvers. Many solvers allow the
specification of application-specific theories as quantified axioms, but their
handling is incomplete outside of narrow special cases.
In this work, we show how SMT solvers can be used to obtain complete decision
procedures for local theory extensions, an important class of theories that are
decidable using finite instantiation of axioms. We present an algorithm that
uses E-matching to generate instances incrementally during the search,
significantly reducing the number of generated instances compared to eager
instantiation strategies. We have used two SMT solvers to implement this
algorithm and conducted an extensive experimental evaluation on benchmarks
derived from verification conditions for heap-manipulating programs. We believe
that our results are of interest to both the users of SMT solvers as well as
their developers
Parallelization of the SUFI2 algorithm: a Windows HPC approach.
The Soil and Water Assessment Tool (SWAT) has been used for evaluating land use changes on water resources worldwide, and like many models, SWAT requires calibration. However, the execution time of these calibrations can be rather long, reducing the time available for proper analysis. This paper presents a Windows approach for calibrating SWAT using a multinodal cluster computer, composed of six computers with i7 processors (3.2 GHz; 12 cores), 8 GB RAM and 1 TB HDD each. The only requirement for this type of cluster is to have 64-bit processors. Our computers were setup with Windows Server HPC 2012 R2, a network switch 10/100, and regular Ethernet cables. We used the SUFI2 algorithm that comes with SWAT-CUP package to perform calibrations with 100 simulations at node level. Calibration runs were configured as follows: 1-12 (1 process interval), and 12-72 (12 processes interval), resulting in 17 runs. Each run was repeated three times, and results are presented as the mean execution time, in order to minimize any influence of resources fluctuations. Results showed that time of execution was reduced by almost half by using nine processes (15 min) in comparison with the one node control (28 min). We observed a linear decrease of execution time from one to nine processes. With additional processes, execution time increased about 23% and stabilized at 80% of the control. All processing is divided into five steps: distribute files (2.24% of all processing time), organize samples (0.89%), run SWAT (47.59%), collect results (46.51%) and cleanup (0.28%)
Modelagem da distribuição geográfica de Eucalyptus tereticornis na região Nordeste do Brasil.
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