186 research outputs found
Multifractal analysis of vertical total electron content (VTEC) at equatorial region and low latitude, during low solar activity
This paper analyses the multifractal aspects of the GPS data (measured
during a period of low solar activity) obtained from two Brazilian stations:
Belém (01.3° S, 48.3° W) and São José dos Campos (SJC)
(23.2° S, 45.9° W). The results show that the respective
geographic sites show important scaling differences as well as similarities
when their multifractal signatures for vertical total electron content (VTEC) are compared. The
<I>f</I>(α) spectra have a narrow shape for great scales, which
indicates the predominance of deterministic phenomena, such as solar
rotation (27 days) over intermittent phenomena. Furthermore, the <I>f</I>(α) spectra for both sites have a strong multifractality
degree at small scales. This strong multifractality degree observed at small
scales (1 to 12 h) at both sites is because the ionosphere over Brazil
is a non-equilibrium system. The differences found were that Belém
presented a stronger multifractality at small scales (1 h to 12 h)
compared with SJC, particularly in 2006. The reason for this behaviour
may be associated with the location of Belém, near the geomagnetic
equator, where at this location the actions of X-rays, ultraviolet, and
another wavelength from the Sun are more direct, strong, and constant
throughout the whole year. Although the SJC site is near ionospheric
equatorial anomaly (IEA) peaks, this interpretation could explain the higher
values found for the intermittent parameter μ for Belém compared
with SJC. Belém also showed the presence of one or two flattening
regions for <I>f</I>(α) spectra at the same scales mentioned before. These
differences and similarities also were interpreted in terms of the IEA
content, where this phenomenon is an important source of intermittence due
the presence of the VTEC peaks at ±20°
geomagnetic latitudes
Comparison of <i>H</i> component geomagnetic field time series obtained at different sites over South America
The
geomagnetic field in the Brazilian sector is influenced by the South American
Magnetic Anomaly (SAMA) that causes a decrease in the magnitude of the local
geomagnetic field when compared to other regions in the world. Thus, the
magnetometer network and data set of space weather over Brazil led by Embrace
are important tools for promoting the understanding of geomagnetic fields
over Brazil. In this sense, in this work we used the HÂ component of
geomagnetic fields obtained at different sites in South America in order to
compare results from the phase coherence obtained from wavelet transform
(WT). Results from comparison between Cachoeira Paulista (CXP) and
Eusébio (EUS), and Cachoeira Paulista and São Luis (SLZ), indicated
that there exist some phenomena that occur simultaneously in both locations,
putting them in the same phase coherence. However, there are other phenomena
putting both locations in a strong phase difference as observed between CXP
and Rio Grande, Argentina (RGA). This study was done for a specific moderate
geomagnetic storm that occurred in March 2003. The results are explained in
terms of nonlinear interaction between physical phenomena acting in distinct
geographic locations and at different times and scales
CaracterĂsticas da carcaça e dos componentes nĂŁo carcaça de cordeiros oriundos de parto simples ou duplo.
Resumo: Um experimento foi conduzido com o objetivo de avaliar as caracterĂsticas da carcaça e dos componentes nĂŁo carcaça de cordeiros nascidos de parto simples ou duplo. Dezesseis cordeiros mestiços Texel Ă— Ile de France, machos nĂŁo castrados, foram desmamados aos 56 dias de idade e abatidos com aproximadamente 28kg de peso corporal. Imediatamente apĂłs o abate, cada componente corporal foi pesado separadamente, sendo as carcaças avaliadas apĂłs 24 horas de refrigeração a 2°C. Os cordeiros oriundos de parto simples apresentaram superioridade no peso e nos rendimentos da carcaça, alĂ©m de maior área de olho de lombo. Por outro lado, proporcionalmente ao peso de corpo vazio, o rĂşmen Ă© maior em cordeiros nascidos de parto duplo, o que resulta incremento da proporção de conteĂşdo gastrintestinal ao abate. Os resultados deste estudo indicam que, quando abatidos a um mesmo peso, cordeiros oriundos de parto simples possuem carcaças de melhor qualidade, em comparação a cordeiros nascidos de parto gemelar. [Carcass and non-carcass traits of single and twin lambs]. Abstract: An experiment was conducted to evaluate the carcass and non-carcass traits of single and twin lambs. Sixteen Texel Ă— Ile de France crossbred, non-castrated male lambs were weaned at 56 days of age and slaughtered at 28kg of body weight. Immediately after the slaughter each body component was individually weighed, while carcasses were evaluated after a 24h period of refrigeration at 2°C. Single lambs presented higher values of carcass weight and carcass dressing percentage. Moreover, the Longissimus muscle area was also greater for single lambs. On the other hand, as a proportion of empty body weight, rumen was greater for twin lambs, increasing their gastrointestinal content at slaughter. The results of this study indicated that at a same slaughter weight single lambs have better quality carcasses in comparison with those from twin lambs
A Description of the Transport Critical Current Behavior of Polycrystalline Superconductors Under the Applied Magnetic Field
Precise phylogenetic analysis of microbial isolates and genomes from metagenomes using PhyloPhlAn 3.0
Microbial genomes are available at an ever-increasing pace, as cultivation and sequencing become cheaper and obtaining metagenome-assembled genomes (MAGs) becomes more effective. Phylogenetic placement methods to contextualize hundreds of thousands of genomes must thus be efficiently scalable and sensitive from closely related strains to divergent phyla. We present PhyloPhlAn 3.0, an accurate, rapid, and easy-to-use method for large-scale microbial genome characterization and phylogenetic analysis at multiple levels of resolution. PhyloPhlAn 3.0 can assign genomes from isolate sequencing or MAGs to species-level genome bins built from >230,000 publically available sequences. For individual clades of interest, it reconstructs strain-level phylogenies from among the closest species using clade-specific maximally informative markers. At the other extreme of resolution, it scales to large phylogenies comprising >17,000 microbial species. Examples including Staphylococcus aureus isolates, gut metagenomes, and meta-analyses demonstrate the ability of PhyloPhlAn 3.0 to support genomic and metagenomic analyses
FISH in analysis of gamma ray-induced micronuclei formation in barley
A micronucleus test in combination with fluorescent in situ hybridization (FISH) using telomere-, centromere-specific probes and 5S and 25S rDNA was used for a detailed analysis of the effects of gamma ray irradiation on the root tip meristem cells of barley, Hordeum vulgare (2n = 14). FISH with four DNA probes was used to examine the involvement of specific chromosomes or chromosome fragments in gamma ray-induced micronuclei formation and then to explain their origin. Additionally, a comparison of the possible origin of the micronuclei induced by physical and chemical treatment: maleic hydrazide (MH) and N-nitroso-N-methylurea (MNU) was done. The micronuclei induced by gamma ray could originate from acentric fragments after chromosome breakage or from whole lagging chromosomes as a result of a dysfunction of the mitotic apparatus. No micronuclei containing only centromeric signals were found. An application of rDNA as probes allowed it to be stated that 5S rDNA–bearing chromosomes are involved in micronuclei formation more often than NOR chromosomes. This work allowed the origin of physically- and chemically-induced micronuclei in barley cells to be compared: the origin of micronuclei was most often from terminal fragments. FISH confirmed its usefulness in the characterization of micronuclei content, as well as in understanding and comparing the mechanisms of the actions of mutagens applied in plant genotoxicity
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