485 research outputs found
The orchid bees (Hymenoptera, Apidae, Euglossina) in a forest fragment from western Paraná state, Brazil
An orchid bee inventory was carried out in Parque Estadual São Camilo, Palotina, Paraná (Brazil); conservation unit with about 400 hectares of Semidecidual Seasonal forest. Three bait traps were installed at the border of the fragment, each one containing the following fragrances: 1,8-cineole, eugenol, and vanilin. Sampling was carried out from 09am to 03pm, October 2011 to June 2012, summing up nine sampling days. A total of 186 specimens distributed among seven species were sampled. Eufriesea violacea with 140 specimens was the most common species, followed by Euglossa fimbriata (31), Euglossa annectans (9), Eulaema nigrita (4), Euglossa cordata (1), Euglossa pleosticta (1), and Exaerete smaragdina (1). According to qualitative and NMDS analysis, the orchid bee fauna of Parque Estadual São Camilo is representative of Semidecidual Seasonal forest, with richness comparable with other assemblages in the southern distribution of Euglossina. The sampled bee richness indicates that forest fragments, even small and isolated, are important in the conservation of this bees.Abelhas das orquÃdeas (Hymenoptera, Apidae, Euglossina) em um fragmento florestal do oeste do Paraná. Um inventário de abelhas das orquÃdeas foi conduzido no Parque Estadual São Camilo, Palotina, Paraná, uma unidade de conservação de cerca de 400 hectares de Floresta Estacional Semidecidual. Três garrafas-armadilha foram instaladas na borda do fragmento, cada uma contendo uma das seguintes essências: 1,8-cineol, eugenol e vanilina. A amostragem foi realizada entre 09 e 15 horas, entre outubro de 2011 e junho de 2012, somando nove dias amostrais. Um total de 186 espécimens distribuÃdos em sete espécies foram amostrados, Eufriesea violacea com 140 indivÃduos foi a mais comum, seguida de Euglossa fimbriata com 31, Euglossa annectans com nove, Eulaema nigrita com quatro, Euglossa cordata, Euglossa pleosticta e Exaerete smaragdina com apenas um indivÃduo amostrado cada. De acordo com análise qualitativa e de NMDS a fauna de Euglossina de Parque Estadual São Camilo é representativa de Floresta Estacional Semidecidual, com riqueza comparável a outras áreas no sul da distribuição do grupo. A riqueza de espécie amostrada indica que fragmentos florestais, mesmo que pequenos e isolados, são importantes na conservação destas abelhas
Forecasting constraints on the baryon mass fraction in the IGM from fast radio bursts and type Ia supernovae
Fast Radio Bursts (FRBs) are transient events with a high energy and short
duration in the radio frequency. By identifying the origin of the pulse, it is
possible to measure the redshift of the host galaxy, which can be used to
constrain cosmological and astrophysical parameters and test aspects of
fundamental physics when combined with the observed dispersion measure ().
However, some factors limit the application of FRBs in cosmology: (i) the
current poor modelling of the fluctuations in the due to spatial variation
in the cosmic electrons density; (ii) the fact that the fraction of baryon mass
in the intergalactic medium () is degenerated with some cosmological
parameters; (iii) the limited current knowledge about host galaxy contribution
(). In this work, we investigate the impact of different redshift
distribution models of FRBs to constrain the baryon fraction in the IGM and
host galaxy contribution. We use a cosmological model-independent method
developed in previous work \cite{Lemos2023} to perform the analysis and combine
simulated FRB data from Monte Carlo simulation and supernovae data. Since the
physical mechanism responsible for the burst is still unknown, we assume four
distribution models for the FRBs, namely gamma-ray bursts (GRB), star formation
rate (SFR), uniform and equidistant (ED). Also, we consider samples with , 30, 100 and 500 points and three different values of the fluctuations of
electron density in the , pc/cm. Our analysis
shows that the GRB, SFR and Uniform distribution models present consistent
results within for the free parameters and
and highlights the crucial role of fluctuations in obtaining more precise
measurements.Comment: 9 pages, 2 figure
Cosmological model-independent constraints on the baryon fraction in the IGM from fast radio bursts and supernovae data
Fast Radio Bursts (FRBs) are millisecond-duration radio transients with an
observed dispersion measure () greater than the expected Milky Way
contribution, which suggests that such events are of extragalactic origin.
Although some models have been proposed to explain the physics of the pulse,
the mechanism behind the FRBs emission is still unknown. From FRBs data with
known host galaxies, the redshift is directly measured and can be combined with
estimates of the to constrain the cosmological parameters, such as the
baryon number density and the Hubble constant. However, the poor knowledge of
the fraction of baryonic mass in the intergalactic medium () and its
degeneracy with the cosmological parameters impose limits on the cosmological
application of FRBs. In this work we present a cosmological model-independent
method to determine the evolution of combining the latest FRBs
observations with localized host galaxy and current supernovae data. We
consider constant and time-dependent parameterizations and show,
through a Bayesian model selection analysis, that a conclusive answer about the
time-evolution of depend strongly on the fluctuations due to the
spatial variation in cosmic electron density (). In particular, our
analysis show that the evidence varies from strong (in favor of a growing
evolution of with redshift) to inconclusive, as larger values of
are considered.Comment: 8 pages, 3 figure
Draft genome sequence of vibrio sp. strain Evh12, a bacterium retrieved from the gorgonian coral eunicella verrucosa.
To shed light on the associations established between Vibrio species and soft corals in coastal ecosystems, we report here the draft genome sequence of Vibrio sp. strain Evh12, a bacterium that has been isolated from the gorgonian coral Eunicella verrucosa and that shows antagonistic activity against Escherichia coli
The bee genus Caenaugochlora (Hymenoptera, Apoidea) and its constituent subgenera, with new species of Caenaugochlora s.str. from Ecuador
Two new species of Caenaugochlora Michener are described and figured from Ecuador. Caenaugochlora quichua sp. n. and C. bennetti sp. n. are both remarkable for the presence of carinate preoccipital carinae, setose compound eyes, strongly rimmed metabasitibial plate, normally pectinate inner metatibial spur, metapostnotal striae not reaching the apical margin, and the male fourth metasomal sterna with lateral projections. The combination of these features intermingle attributes of the presently recognized subgenera, while others are unique to the genus as a whole. A revised diagnosis is provided for the genus and its two subgenera, with Caenaugochlora s.str. accommodating C. bennetti and C. quichua, and brief comments made regarding the implications of the characters exhibited by the aforementioned species
Assessment of sediment contamination in an impacted estuary: differential effects and adaptations of sentinel organisms and implications for biomonitoring
Conferência realizada em Lisboa, de 6-9 November de 2013Estuarine pollution is reflected in the concentration of toxicants in sediments, depending on their geochemical properties, since sediments trap substances from the water column, either dissolved or bound to suspended matter. However, determining risk of sediment contaminants to biota has many constraints. For such reason, integrative approaches are keystone. Taking the Sado estuary (SW Portugal) as a case study, contrasted to a reference estuary (the Mira) within the same geographical location, the present study aimed at integrating sediment contamination with the effects and responses to pollutants in distinct benthic organisms with commercial and ecological value
Can the angular scale of cosmic homogeneity be used as a cosmological test?
In standard cosmology, the cosmic homogeneity scale is the transition scale
above which the patterns arising from non-uniformities -- such as groups and
clusters of galaxies, voids, and filaments -- become indistinguishable from a
random distribution of sources. Recently, different groups have investigated
the feasibility of using such a scale as a cosmological test and arrived at
different conclusions. In this paper, we complement and extend these studies by
exploring the evolution of the spatial () and angular ()
homogeneity scales with redshift, assuming a spatially flat, -Cold
Dark Matter %(CDM) universe and linear cosmological perturbation
theory. We confirm previous results concerning the non-monotonicity of
with the matter density parameter but also show
that it exhibits a monotonical behavior with the Hubble constant within a
large redshift interval. More importantly, we find that, for ,
the angular homogeneity scale not only presents a monotonical behavior with
and but is quite sensitive to , especially at higher
redshifts. These results, therefore, raise the possibility of using
as a new, model-independent way to constrain cosmological parameters.Comment: 10 pages, 24 figure
Write-erase and read paper memory transistor
Applied Physics Letters, Vol.93, issue 20We report the architecture and the performances of a memory based on a single field-effect transistor built on paper able to write-erase and read. The device is composed of natural multilayer cellulose
fibers that simultaneously act as structural support and gate dielectric; active and passive multicomponent amorphous oxides that work as the channel and gate electrode layers, respectively,complemented by the use of patterned metal layers as source/drain electrodes. The devices exhibit a large counterclockwise hysteresis associated with the memory effect, with a turn-on voltage shift between 1 and −14.5 V, on/off ratio and saturation mobilities of about 104 and 40 cm2 V−1 s−1, respectively, and estimated charge retention times above 14 000 h
The angular scale of homogeneity with SDSS-IV DR16 Luminous Red Galaxies
We report measurements of the angular scale of cosmic homogeneity
() using the recently released luminous red galaxy sample of the
sixteenth data release of the Sloan Digital Sky Survey (SDSS-IV LRG DR16). It
consists of a model-independent method, as we only use the celestial
coordinates of these objects to carry out such an analysis. The observational
data is divided into thin redshift bins, namely , ,
and , in order to avoid projection biases, and we estimate our
uncertainties through a bootstrap method and a suite of mock catalogues. We
find that the LRGs exhibit an angular scale of homogeneity consistent with the
predictions of the standard cosmology within the redshift interval studied.
Considering the bootstrap method, in which the measurements are obtained in a
model-independent way, we found at 1 level that deg, deg and
deg. Such results are in good
agreement with the ones obtained using mock catalogues built under the
assumption of the standard cosmological model.Comment: 13 pages, 4 figures, 3 tables. References updated; matches version
published in JCA
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