2,535 research outputs found
Report of Macraspis pseudochrysis Landin, 1956 (Coleoptera: Scarabaeidae: Rutelinae) on açai palms (Euterpe oleracea Mart.) in floodplains in the state of Amapá, Brazil.
O açaizeiro [Euterpe oleracea] é uma palmeira da Amazônia Oriental encontrada com mais freqüência no estuário do Rio Amazonas. Recentemente, ribeirinhos em diferentes regiões do estado do Amapá observaram uma espécie de coleóptero que ataca as inflorescências de açaízeiros. Com o objetivo de identificar exemplares de Coleoptera em inflorescências de E. oleracea no estado do Amapá, Brasil, foram coletados 13 indivíduos nas localidades de Abacate da Pedreira (dois exemplares), Ariri (seis)(ambas em Macapá) e no município de Mazagão (cinco), entre outubro de 2010 e fevereiro de 2011. Os coleópteros foram coletados diretamente nas inflorescências de açaizeiros com auxílio de rede entomológica, conservados e enviados para identificação. Todos os indivíduos pertencem à espécie Macraspis pseudochrysis Landin, 1956 (Coleoptera: Scarabaeidae: Rutelinae). Este é o primeiro registro de ocorrência de M. pseudochrysis em E. oleracea na região neotropical
Truly scalable K-Truss and max-truss algorithms for community detection in graphs
The notion of k-truss has been introduced a decade ago in social network analysis and security for community detection, as a form of cohesive subgraphs less stringent than a clique (set of pairwise linked nodes), and more selective than a k-core (induced subgraph with minimum degree k). A k-truss is an inclusion-maximal subgraph Hin which each edge belongs to at least k-2triangles inside H. The truss decomposition establishes, for each edge e, the maximum kfor which ebelongs to a k-truss. Analogously to the largest clique and to the maximum k-core, the strongest community for k-truss is the max-truss, which corresponds to the k-truss having the maximum k. Even though the computation of truss decomposition and of the max-truss takes polynomial time, on a large scale, it suffers from handling a potentially cubic number of wedges. In this paper, we provide a new algorithm FMT, which advances the state of the art on different sides: lower execution time, lower memory usage, and no need for expensive hardware. We compare FMT experimentally with the most recent state-of-the-art algorithms on a set of large real-world and synthetic networks with over a billion edges. The massive improvement allows FMT to compute the max-truss of networks of tens of billions of edges on a single standard server machine
Star-forming dwarf galaxies in the Virgo cluster: the link between molecular gas, atomic gas, and dust
We present CO(1-0) and CO(2-1) observations of a sample of 20
star-forming dwarfs selected from the Herschel Virgo Cluster Survey, with
oxygen abundances ranging from 12 + log(O/H) ~ 8.1 to 8.8. CO emission is
observed in ten galaxies and marginally detected in another one. CO fluxes
correlate with the FIR 250 m emission, and the dwarfs follow the same
linear relation that holds for more massive spiral galaxies extended to a wider
dynamical range. We compare different methods to estimate H2 molecular masses,
namely a metallicity-dependent CO-to-H2 conversion factor and one dependent on
H-band luminosity. The molecular-to-stellar mass ratio remains nearly constant
at stellar masses <~ 10 M, contrary to the atomic hydrogen
fraction, M/M, which increases inversely with M. The flattening
of the M/M ratio at low stellar masses does not seem to be related
to the effects of the cluster environment because it occurs for both
HI-deficient and HI-normal dwarfs. The molecular-to-atomic ratio is more
tightly correlated with stellar surface density than metallicity, confirming
that the interstellar gas pressure plays a key role in determining the balance
between the two gaseous components of the interstellar medium. Virgo dwarfs
follow the same linear trend between molecular gas mass and star formation rate
as more massive spirals, but gas depletion timescales, , are not
constant and range between 100 Myr and 6 Gyr. The interaction with the Virgo
cluster environment is removing the atomic gas and dust components of the
dwarfs, but the molecular gas appears to be less affected at the current stage
of evolution within the cluster. However, the correlation between HI deficiency
and the molecular gas depletion time suggests that the lack of gas
replenishment from the outer regions of the disc is lowering the star formation
activity.Comment: 19 pages, 11 figures, accepted for publication in Astronomy &
Astrophysic
Sensitivity of the sorghum yield to individual changes in climate parameters: modelling based approach.
Based on sensitivity analyses the effect of changing in climate on sorghum has been investigated. This has been achieved by conducting crop modeling experiments carried out with weather observations and output of global climate models. As can be anticipated results demonstrated that the sorghum yield is more sensitive to rainfall, solar radiation and CO2 concentration. However, the increase in CO2 concentration has a positive effect on yield in years that the crop is submitted to water stress. This effect is extremely reduced under well watered conditions and therefore is subject to the climate inter-annual variability. Accumulated solar radiation along the sorghum cycle below 1900 MJ m?2 has also been shown to reduce the yield. Compared to other weather variables the sorghum yield is less sensitive to changes in relative humidity. In this sense, changes in stomatal closure and therefore photosyntesis is not highly dependent on water vapor pressure. These finds can be applied for both climate observations and global models output
Microbiota network and mathematic microbe mutualism in colostrum and mature milk collected in two different geographic areas: Italy versus Burundi
Human milk is essential for the initial development of newborns, as it provides
all nutrients and vitamins, such as vitamin D, and represents a great source of
commensal bacteria. Here we explore the microbiota network of colostrum and
mature milk of Italian and Burundian mothers using the auto contractive map
(AutoCM), a new methodology based on artificial neural network (ANN)
architecture. We were able to demonstrate the microbiota of human milk to be a
dynamic, and complex, ecosystem with different bacterial networks among different
populations containing diverse microbial hubs and central nodes, which change
during the transition from colostrum to mature milk. Furthermore, a greater
abundance of anaerobic intestinal bacteria in mature milk compared with colostrum
samples has been observed. The association of complex mathematic systems such as
ANN and AutoCM adopted to metagenomics analysis represents an innovative approach
to investigate in detail specific bacterial interactions in biological
samples
Review: potential biotechnological assets related to plant immunity modulation applicable in engineering disease-resistant crops.
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