The weekly dependence of pollutant aerosols in the urban environment of Lisbon (Portugal) is inferred from the records of atmospheric electric field at Portela meteorological station (38°47′N, ...9°08′W). Measurements were made with a Bendorf electrograph. The data set exists from 1955 to 1990, but due to the contaminating effect of the radioactive fallout during 1960 and 1970s, only the period between 1980 and 1990 is considered here. Using a relative difference method a weekly dependence of the atmospheric electric field is found in these records, which shows an increasing trend between 1980 and 1990. This is consistent with a growth of population in the Lisbon metropolitan area and consequently urban activity, mainly traffic. Complementarily, using a Lomb-Scargle periodogram technique the presence of a daily and weekly cycle is also found. Moreover, to follow the evolution of theses cycles, in the period considered, a simple representation in a colour surface plot representation of the annual periodograms is presented. Further, a noise analysis of the periodograms is made, which validates the results found. Two datasets were considered: all days in the period, and fair-weather days only.
In the assembly of biological networks it is important to provide reliable interactions in an effort to have the most possible accurate representation of real-life systems. Commonly, the data used to ...build a network comes from diverse high-throughput essays, however most of the interaction data is available through scientific literature. This has become a challenge with the notable increase in scientific literature being published, as it is hard for human curators to track all recent discoveries without using efficient tools to help them identify these interactions in an automatic way. This can be surpassed by using text mining approaches which are capable of extracting knowledge from scientific documents. One of the most important tasks in text mining for biological network building is relation extraction, which identifies relations between the entities of interest. Many interaction databases already use text mining systems, and the development of these tools will lead to more reliable networks, as well as the possibility to personalize the networks by selecting the desired relations. This review will focus on different approaches of automatic information extraction from biomedical text that can be used to enhance existing networks or create new ones, such as deep learning state-of-the-art approaches, focusing on cancer disease as a case-study.
We have studied how the energy spectrum of muons at production affects some of the most common measurements related to muons in extensive air shower studies, namely, the number of muons at the ...ground, the slope of the lateral distribution of muons, the apparent muon production depth, and the arrival time delay of muons at ground. We found that by changing the energy spectrum by an amount consistent with the difference between current models (namely EPOS-LHC and QGSJet-II.04), the muon surface density at ground increases 5% at 20° zenith angle and 17% at 60° zenith angle. This effect introduces a zenith angle dependence on the reconstructed number of muons which might be experimentally observed. The maximum of the muon production depth distribution at 40° increases ∼ 10 g/cm2 and ∼ 0 g/cm2 at 60°, which, from pure geometrical considerations, increases the arrival time delay of muons. There is an extra contribution to the delay due to the subluminal velocities of muons of the order of ∼ 3 ns at all zenith angles. Finally, changes introduced in the logarithmic slope of the lateral density function are less than 2%.
ABSTRACT
Gamma-ray Bursts (GRB) were discovered by satellite-based detectors as powerful sources of transient γ-ray emission. The Fermi satellite detected an increasing number of these events with ...its dedicated Gamma-ray Burst Monitor (GBM), some of which were associated with high energy photons ($E \gt 10$ GeV), by the Large Area Telescope (LAT). More recently, follow-up observations by Cherenkov telescopes detected very high energy emission ($E \gt 100$ GeV) from GRBs, opening up a new observational window with implications on the interpretation of their central engines and on the propagation of very energetic photons across the Universe. Here, we use the data published in the 2nd Fermi-LAT Gamma Ray Burst Catalogue to characterize the duration, luminosity, redshift, and light curve of the high energy GRB emission. We extrapolate these properties to the very high energy domain, comparing the results with available observations and with the potential of future instruments. We use observed and simulated GRB populations to estimate the chances of detection with wide-field ground-based γ-ray instruments. Our analysis aims to evaluate the opportunities of the Southern Wide-field-of-view Gamma-ray Observatory (SWGO), to be installed in the Southern Hemisphere, to complement CTA. We show that a low-energy observing threshold ($E_{low} \lt 200$ GeV), with good point source sensitivity ($F_{lim} \approx 10^{-11} \,\mathrm{erg\, cm^{-2}\, s^{-1}}$ in $1$ yr), are optimal requirements to work as a GRB trigger facility and to probe the burst spectral properties down to time-scales as short as $10$ s, accessing a time domain that will not be available to Imaging Atmospheric Cherenkov Telescopes instruments.
A new concept for the direct measurement of muons in air showers is presented. The concept is based on resistive plate chambers (RPCs), which can directly measure muons with very good space and time ...resolution. The muon detector is shielded by placing it under another detector able to absorb and measure the electromagnetic component of the showers such as a water-Cherenkov detector, commonly used in air shower arrays. The combination of the two detectors in a single, compact detector unit provides a unique measurement that opens rich possibilities in the study of air showers.
Maize (Zea mays L.) is of socioeconomic importance as an essential food for human and animal nutrition. However, cereals are susceptible to attack by mycotoxin-producing fungi, which can damage ...health. The methods most commonly used to detect and quantify mycotoxins are expensive and time-consuming. Therefore, alternative non-destructive methods are required urgently. The present study aimed to use near-infrared spectroscopy with hyperspectral imaging (NIR-HSI) and multivariate image analysis to develop a rapid and accurate method for quantifying fumonisins in whole grains of six naturally contaminated maize cultivars. Fifty-eight samples, each containing 40 grains, were subjected to NIR-HSI. These were subsequently divided into calibration (38 samples) and prediction sets (20 samples) based on the multispectral data obtained. The averaged spectra were subjected to various pre-processing techniques (standard normal variate (SNV), first derivative, or second derivative). The most effective pre-treatment performed on the spectra was SNV. Partial least squares (PLS) models were developed to quantify the fumonisin content. The final model presented a correlation coefficient (R2) of 0.98 and root mean square error of calibration (RMSEC) of 508 µg.kg-1 for the calibration set, an R2 of 0.95 and root mean square error of prediction (RMSEP) of 508 µg.kg-1 for the test validation set and a ratio of performance to deviation of 4.7. It was concluded that NIR-HSI with partial least square regression is a rapid, effective, and non-destructive method to determine the fumonisin content in whole maize grains.
The goals of this study were to evaluate the persistence and the virulence potential of Listeria monocytogenes isolated from beef carcasses obtained in processing facilities in the southern region of ...Rio Grande do Sul, Brazil, based on pulsed-field gel electrophoresis (PFGE), invasion ability in human colorectal carcinoma cells (HCT-116), internalin A (InlA) expression by Western blot, and identification of mutation points in inlA. PFGE profiles demonstrated that L. monocytogenes isolates were grouped based on their previously identified lineages and serogroups (lineage I: serogroup IIb, n = 2, and serogroup IVb, n = 5; lineage II: serogroup IIc, n = 5). Isolates with indistinguishable genetic profiles through this method were obtained from different slaughterhouses and sampling steps, with as much as a 3-year interval. Seven isolates showed high invasion ability (2.4 to 7.4%; lineage I, n = 6, and lineage II, n = 1) in HCT and expressed InlA. Five isolates showed low cell invasion ability (0.6 to 1.4%; lineage I, n = 1, and lineage II, n = 4) and did not express InlA, and two of them (lineage II, serogroup IIc) presented mutations in inlA that led to premature stop codon type 19 at position 326 (GAA → TAA). The results demonstrated that most L. monocytogenes isolates from lineage I expressed InlA and were the most invasive in HCT, indicating their high virulence potential, whereas most isolates from lineage II showed attenuated invasion because of nonexpression of InlA or the presence of premature stop codon type 19 in inlA. The obtained results demonstrated that L. monocytogenes with indistinguishable PFGE profiles can persist or be reintroduced in beef processing facilities in the studied region and that differences in their virulence potential are based on their lineages and serogroups.
The electrical power system is susceptible to several faults, which can cause the system to malfunction. Among these, the ones that occur in the busbars of substations stand out. The main bus of a ...substation can concentrate a large amount of power and many derivations to service electrical loads, making it an element of high importance for the reliability of the system. Although the buses have a low incidence of faults, they are considered critical elements of the electrical power system, as their operating output can cause a large number of forced outages. This situation makes the protection of this component of paramount importance. There are currently two widely used bus differential protection techniques: high-impedance and low-impedance bus differential protection. The second technique is more commonly used due to the possibility of sharing current transformers (CTs). However, the high cost and greater requirements for maintenance makes the differential protection of busbars in distribution or sub-transmission substations unfeasible. With the advent and implementation of the IEC 61850 standard, modern protection systems based on this standard offer significant advantages, such as lower expenses with installation, wiring, commissioning and maintenance; adaptable bus configuration; use of different CT ratios; considerably minimized susceptibility to CT saturation; lower risks of open secondary CT circuits and viability of implantation in distribution substations. The objective of this review is to present an overview of the works found in the literature on substation busbar differential protection, considering classical methods and those based on the IEC 61850 standard.
The photovoltaic solar cell is a complementary source of energy, being a solution for energy generation. The Grätzel cells or dye-sensitized solar cells (DSSCs) represent a substitute for ...silicon-based solar cells that are interesting owing to their low-cost manufacturing, non-toxicity with a good recovery efficiency. Herein, the novel natural dyes containing luteolin molecules were prepared by four specimens of
Gerbera jamesonii
flowers with different colors of petals such as coral, orange, red and yellow. The light absorption characteristics and the presence of functional groups of extracted dyes were recognized by Ultraviolet–Visible (UV–Vis) spectroscopy and Fourier transformed infrared (FTIR) spectroscopy, respectively. The energy bandgap of the extracted dyes has been investigated by UV–Vis and Tauc relation. In addition, DSSCs were constructed via newly extracted dye adsorbed nanosized titanium dioxide (TiO
2
) as a photoanode, nanostructured platinum as a photocathode and redox electrolyte. The photoanodes and photocathodes surface roughness was analyzed by atomic force microscope (AFM). Further, the morphologies of photoanodes and photocathodes are characterized by field scanning electron microscope (FESEM). The photovoltaic performances were carried out to recognize the influences of the photoanodes and the interactions with different
G. jamesonii
flowers dye extract molecules on the overall cells efficiency. The photoelectrochemical properties for instance open-circuit voltages (
V
oc
), short-circuit photocurrent densities (
J
sc
), fill factors (FF), and efficiency of energy conversion (
η
) were also investigated. The maximum power conversion efficiency of the cell has reached 1.54%, thus obtaining an excellent value when compared with the literature for different concentrations of flavonoids and showing the great potential of these flowers in the application of solar cells sensitized by natural dyes.
Organic solar cells are an excellent alternative to the traditional energy sources turning the dye-sensitized solar cells (DSSCs) into a promising choice for low-cost device fabrication. In this ...paper, a natural dye extracted from petals of
Lantana repens
and
Solidago canadensis
flowers was used as light-harvesting units to construct DSSCs. The extracted dyes were optically analyzed using ultraviolet–visible (UV–Vis) absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy indicated the existence of a high concentration of β-carotene in the
Lantana repens
flowers and the condensed tannin in the
Solidago canadensis
flowers. The photoanode and photocathode film morphologies and surface topographies were examined through atomic force microscope (AFM) and scanning electron microscope (SEM), respectively. The photovoltaic and electrochemical impedance spectroscopy studies showed the characteristics of the as-fabricated DSSCs and the influence of the extracted dye molecules on the cells’ efficiency. The
Solidago canadensis
and
Lantana repens
dye extracts showed a photosensitized performance efficiency of 0.31% and 0.12% under AM 1.5G illumination of sunlight, respectively. The application of natural dyes as photosensitizers shows a promising future to extend the studies from the natural dye-based DSSCs for fabrication in large-scale production.
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