The influence of drying conditions (air temperature and relative humidity) on mechanical properties, solubility in water, and color of two kinds of soy protein isolate film: a commercial one (CSPI) ...and other obtained under laboratory conditions (LSPI) were evaluated using the response surface methodology (RSM). Soy protein films were prepared by casting using glycerol as plasticizer. The films were dried in a chamber with air circulation under controlled conditions of relative humidity (24%, 30%, 45%, 60%, 66%) and air temperature (34, 40, 55, 70, 76
°C). It was verified that mechanical properties of films made from LSPI and CSPI are influenced in a very different way by the drying conditions due to a diverse initial protein conformation in both materials, as was revealed by DSC and SDS–Page studies. The solubility of the LSPI film was affected by temperature and relative humidity, being lowest (∼50%) for films obtained at high RH and temperatures ranging from 45 to 76
°C. For CSPI films, in contrast, solubility did not depend on the drying process and it remained relatively constant (∼40%). The optimal drying conditions determined by RSM were: 70
°C and 30% RH for CSPI films and 60
°C and 60% RH for LSPI films. Dried under these conditions, CSPI films presented a higher tensile strength, lower elongation at break, lower solubility and better water and oxygen permeability than LSPI ones.
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•Red propolis ethanolic extract (RPEE) have good antioxidant/antimicrobial activities.•Cloves (CEO) and Basil (BEO) essential oils used together with RPEE produces active ...films.•Active films presented antimicrobial activity against St. aureus and S. Enteritidis.•Active films presented physical properties similar to those of control films.
Red propolis ethanolic extract (RPEE) and essential oils are well-known for their antimicrobial and antioxidant activities. The aim of this study was to develop gelatin-based active films loaded with RPEE in combinations with clove essential oil and/or basil essential oil and to study the effects of these components on the antioxidant, antimicrobial and physical properties of films. The active films were produced by a spreading technique, with RPEE and essential oils in different concentrations. These compounds were evaluated for antioxidant and antimicrobial activities, as well as for their minimal inhibitory concentration and minimal bactericidal concentration. The films were characterized through physical, antimicrobial and antioxidant properties. RPEE and essential oils both presented high antioxidant activity. All essential oils showed antimicrobial activity against all evaluated bacteria, while the RPEE presented activity only against the Gram(+) bacteria. All films showed antioxidant activity. Films with clove essential oil presented the highest total contents of phenol and antioxidant activity. The RPEE in films increased their UV/visible light barrier and modified their thermal properties. Changes in infrared spectra suggested possible interactions between phenols of the active compounds and the gelatin peptides. Overall, physical properties of active films were typical of biopolymer-based films.
Bottom‐type spread F events were observed in the south American equatorial region by a VHF coherent radar and an ionosonde at São Luís (2.5°S, 44.3°W), an ionosonde at Fortaleza (3.9°S, 38.4° W) and ...an airglow OI 630.0 nm imager at Cariri (7.4°S, 36.5°W) and Brasilia (14.8°S, 47.6°W). In the evening of September 30, 2005, a long duration (∼70 minutes) bottom side scattering layer, confined in a narrow height region, was observed. At the same time all‐sky imager observed sinusoidal intensity depletions in the zonal plane extending more than 1500 km and elongated along the magnetic meridian. No strong spread F structures developed during the period. Subsequently well developed plasma bubbles were observed. This suggests that the observed bottom‐type spread F is an initial phase of the plasma bubbles. We report, for the first time, longitudinal and latitudinal extension of the bottom‐type spread F as diagnosed by optical imagers.
In this work, we report the ionospheric F‐layer responses over the Brazilian equatorial sector to a counter electrojet event that occurred during the solar minimum period of June 2009. The data ...collected by the Digisonde over São Luis (2.33°S; 44°W; I: −4751°; Dip. Lat. 238°S) showed a strong modification in the ionospheric F2 layer trace, which in this case appeared to be “broken in half.” In this process, the first part of the F2 layer (lower frequency) was thrown down whilst the upper part remained at higher altitudes. Such characteristics occurred simultaneously with an abrupt decrease in the strength of equatorial electrojet and with intensification in the auroral activity. The origin of this phenomenon seems to have a local nature and seems not to be connected to any magnetic disturbance since similar responses were not observed in other longitudinal and latitudinal sectors. Excluding this possibility, we assume that the strong changes observed in the F layer over São Luis had been caused probably by the gravity wave (GW) propagation, as seen in the downward phase propagation of the altitude contours with time over São Luis and Fortaleza and the remarkable signatures in ionograms over both regions, such as the forking traces that are typically caused by GWs.
Key Points
Anomalous responses of the ionospheric F layer over Brazil during a counter electrojet (CEJ) event
Weakening and subsequent reversal of daytime equatorial electrojetss is noticed during a period of intense gravity wave (GW) activity
The ionospheric F2 layer stratification under a CEJ event probably due to the GW propagation
We analyse maps of the spatially resolved nebular emission of ≈1500 star-forming galaxies at z ≈ 0.6-2.2 from deep K-band Multi-Object Spectrograph and MUSE observations to measure the average shape ...of their rotation curves. We use these to test claims for declining rotation curves at large radii in galaxies at z ≈ 1-2 that have been interpreted as evidence for an absence of dark matter. We show that the shape of the average rotation curves, and the extent to which they decline beyond their peak velocities, depends upon the normalization prescription used to construct the average curve. Normalizing in size by the galaxy stellar disc-scale length after accounting for seeing effects (Rd^' }), we construct stacked position-velocity diagrams that trace the average galaxy rotation curve out to 6Rd^' } (≈13 kpc, on average). Combining these curves with average H I rotation curves for local systems, we investigate how the shapes of galaxy rotation curves evolve over ≈10 Gyr. The average rotation curve for galaxies binned in stellar mass, stellar surface mass density and/or redshift is approximately flat, or continues to rise, out to at least 6Rd^' }. We find a trend between the outer slopes of galaxies' rotation curves and their stellar mass surface densities, with the higher surface density systems exhibiting flatter rotation curves. Drawing comparisons with hydrodynamical simulations, we show that the average shapes of the rotation curves for our sample of massive, star-forming galaxies at z ≈ 0-2.2 are consistent with those expected from lambda cold dark matter theory and imply dark matter fractions within 6Rd of at least ≈60 per cent.
In this study we investigate the response of the equatorial F layer to disturbance zonal electric field associated with IMF (interplanetary magnetic field) variations dominated by a strong northward ...Bz episode during the magnetic storm that occurred on 21 January, 2005. We compared the results obtained from Digisondes operated at Fortaleza, Brazil (Geogr. 3.9°S, 38.45°W; dip angle: −11.7°) and Jicamarca, Peru (Geogr. 12.0°S, 76.8°W; dip angle: 0.64°). A large auroral activity (AE) intensification that occurred at ∼1715 UT produced a large F‐layer peak height increase (from 300 km to 600 km) over Jicamarca with no noticeable simultaneous effect over Fortaleza. Then the Bz turning northward at ∼1940 UT with a rapid change in AE that was accompanied by a large decrease of F layer height and total suppression of the PRE over Fortaleza with no simultaneous effect over Jicamarca. Strong increase in the AE index (from ∼400 to 1000 nT) with superimposed oscillations, under Bz North, that soon followed was associated with increases in both the F layer height and the vertical drift velocity over Fortaleza (at 2130 UT), with no corresponding signatures over Jicamarca. These remarkable contrasting responses to prompt penetration electric field (PPEF) as well as to disturbance wind dynamo electric field (DDEF) and other effects observed at the two locations separated only by 2 h in LT in the South American sector are presented and discussed in this paper. Effects onspread‐F development and foF2 behavior during this storm event are also addressed in this work.
Key Points
Prompt penetration eastward electric field under Bz South as well as Bz North
Large contrasts in the storm time response between Fortaleza and Jicamarca
Modulation of the F‐layer by large scale gravity waves
The main purpose of this paper is to investigate the response of the ionospheric F layer in the American and African sectors during the intense geomagnetic storm which occurred on 30 September–01 ...October 2012. In this work, we used observations from a chain of 20 GPS stations in the equatorial, low- and mid-latitude regions in the American and African sectors. Also, in this study ionospheric sounding data obtained during 29th September to 2nd October, 2012 at Jicamarca (JIC), Peru, São Luis (SL), Fortaleza (FZ), Brazil, and Port Stanley (PST), are presented. On the night of 30 September–01 October, in the main and recovery phase, the h´F variations showed an unusual uplifting of the F region at equatorial (JIC, SL and FZ) and mid- (PST) latitude stations related with the propagations of traveling ionospheric disturbances (TIDs) generated by Joule heating at auroral regions. On 30 September, the VTEC variations and foF2 observations at mid-latitude stations (American sector) showed a long-duration positive ionospheric storm (over 6h of enhancement) associated with large-scale wind circulations and equatorward neutral winds. Also, on 01 October, a long-duration positive ionospheric storm was observed at equatorial, low- and mid- latitude stations in the African sector, related with the large-scale wind circulations and equatorward neutral winds. On 01 and 02 October, positive ionospheric storms were observed at equatorial, low- and mid-latitude stations in the American sector, possibly associated with the TIDs and an equatorward neutral wind. Also, on 01 October negative ionospheric storms were observed at equatorial, low- and mid-latitude regions in the American sector, probably associated with the changes in the O/N2 ratio. On the night of 30 September–01 October, ionospheric plasma bubbles were observed at equatorial, low- and mid- latitude stations in the South American sector, possibly associated with the occurrence of geomagnetic storm.
•This study investigates the effects of a geomagnetic storm in the ionosphere.•We present ionospheric sounding observations in the American and African sectors.•An unusual uplifting of the F layer was observed in the American sector.•Positive ionospheric storms were observed in the American and African sectors.•Plasma bubbles were observed in the American sector up to mid-latitude region.
Context.
In modern astronomy, machine learning has proved to be efficient and effective in mining big data from the newest telescopes.
Aims.
In this study, we construct a supervised machine-learning ...algorithm to classify the objects in the Javalambre Photometric Local Universe Survey first data release (J-PLUS DR1).
Methods.
The sample set is featured with 12-waveband photometry and labeled with spectrum-based catalogs, including Sloan Digital Sky Survey spectroscopic data, the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, and VERONCAT – the Veron Catalog of Quasars & AGN. The performance of the classifier is presented with the applications of blind test validations based on RAdial Velocity Extension, the
Kepler
Input Catalog, the Two Micron All Sky Survey Redshift Survey, and the UV-bright Quasar Survey. A new algorithm was applied to constrain the potential extrapolation that could decrease the performance of the machine-learning classifier.
Results.
The accuracies of the classifier are 96.5% in the blind test and 97.0% in training cross-validation. The
F
1
-scores for each class are presented to show the balance between the precision and the recall of the classifier. We also discuss different methods to constrain the potential extrapolation.
In this short work, it was evaluated the moisture absorption and loss (desorption) in gelatin films containing different plasticizer types and contents. A special desiccator was developed for ...moisture control. An alternative microwave method was used for this study. The results show that the films containing glycerol presented greater water absorption in comparison to films containing ethyleneglycol, diethyleneglycol and polypropyleneglycol, which was attributed to the higher hydrophilic nature of the glycerol.
Aims.
Our goal is to estimate the star formation main sequence (SFMS) and the star formation rate density (SFRD) at
z
≤ 0.017 (
d
≲ 75 Mpc) using the Javalambre Photometric Local Universe Survey ...(J-PLUS) first data release, that probes 897.4 deg
2
with twelve optical bands.
Methods.
We extract the H
α
emission flux of 805 local galaxies from the J-PLUS filter
J
0660, being the continuum level estimated with the other eleven J-PLUS bands, and the dust attenuation and nitrogen contamination corrected with empirical relations. Stellar masses (
M
⋆
), H
α
luminosities (
L
H
α
), and star formation rates (SFRs) were estimated by accounting for parameters covariances. Our sample comprises 689 blue galaxies and 67 red galaxies, classified in the (
u
−
g
) vs. (
g
−
z
) color–color diagram, plus 49 AGN.
Results.
The SFMS is explored at log
M
⋆
≳ 8 and it is clearly defined by the blue galaxies, with the red galaxies located below them. The SFMS is described as log SFR = 0.83log
M
⋆
− 8.44. We find a good agreement with previous estimations of the SFMS, especially those based on integral field spectroscopy. The H
α
luminosity function of the AGN-free sample is well described by a Schechter function with log
L
H
α
∗
= 41.34, log
ϕ
*
= −2.43, and
α
= −1.25. Our measurements provide a lower characteristic luminosity than several previous studies in the literature.
Conclusions.
The derived star formation rate density at
d
≲ 75 Mpc is log
ρ
SFR
= −2.10 ± 0.11, with red galaxies accounting for 15% of the SFRD. Our value is lower than previous estimations at similar redshift, and provides a local reference for evolutionary studies regarding the star formation history of the Universe.
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