Abstract
2+We present a methodology for the use of sulphur as global metallicity tracer in galaxies, allowing performing a complete abundance analysis using only the red-to-near-infrared spectral ...region. We have applied it to a compilation of high-quality data split into two samples: H ii regions (DHR) in spiral and irregular galaxies, and dwarf galaxies dominated by a strong starburst (H ii Gal). Sulphur abundances have been derived by direct methods under the assumption of an ionization structure composed of two zones: an intermediate-ionization one where S++ is originated, and a low-ionization one where S+ is formed. Ionization correction factors (ICF) have been calculated from the Ar/Ar3+ ratio and are shown to correlate with the hardness of the radiation field. Only about 10 per cent of the objects show S3+ contributions to the total abundance larger than 30 per cent. A good correlation exists between sulphur abundance and ionizing temperature with low-metallicity objects being ionized by hotter stars. No correlation is found between ionization parameter and total S/H abundance. Most of the H ii Gal objects show S/O ratios below the solar value and a trend for increasing S/O ratios with increasing sulphur abundances, while DHR objects show S/O ratios larger than solar and a tendency for lower S/O ratios for higher metallicities. Finally, we present a calibration of the sulphur abundance through the S23 parameter that remains single valued up to sulphur abundances well beyond the solar value. S23 is independent of the ionization parameter and only weakly dependent on ionizing temperature.
ABSTRACT
This work aims to derive the physical properties of the circumnuclear star-forming region in the ring of the face-on spiral NGC 7742 using integral field spectroscopy observations. We have ...selected 88 individual ionizing clusters that power H ii regions populating the ring of the galaxy that may have originated in a minor-merger event. For the H ii regions, the rate of Lyman continuum photon emission is between 0.025 and 1.5 × 1051, which points to these regions being ionized by star clusters. Their electron density, ionization parameter, filling factor, and ionized hydrogen mass show values consistent with those found in other studies of similar regions and their metal abundances, as traced by sulphur have been found to be between 0.25 and 2.4 times solar, with most regions showing values slightly below solar. The equivalent temperature of the ionizing clusters is relatively low, below 40 000 K, which is consistent with the high elemental abundances derived. The young stellar population of the clusters has contributions of ionizing and non-ionizing populations with ages around 5 and 300 Ma, respectively. The masses of ionizing clusters once corrected for the contribution of underlying non-ionizing populations were found to have a mean value of 3.5 × 104 M⊙, comparable to the mass of ionized gas and about 20 per cent of the corrected photometric mass.
Timing of food intake associates with body weight regulation, insulin sensitivity and glucose tolerance. However, the mechanism is unknown. The aim of this study was to investigate the effects of ...changes in meal timing on energy-expenditure, glucose-tolerance and circadian-related variables.
Thirty-two women (aged 24±4 years and body mass index 22.9±2.6 kg m(-2)) completed two randomized, crossover protocols: one protocol (P1) including assessment of resting-energy expenditure (indirect-calorimetry) and glucose tolerance (mixed-meal test) (n=10), the other (P2) including circadian-related measurements based on profiles in salivary cortisol and wrist temperature (Twrist) (n=22). In each protocol, participants were provided with standardized meals (breakfast, lunch and dinner) during the two meal intervention weeks and were studied under two lunch-eating conditions: Early Eating (EE; lunch at 13:00) and Late Eating (LE; lunch 16:30).
LE, as compared with EE, resulted in decreased pre-meal resting-energy expenditure (P=0.048), a lower pre-meal protein-corrected respiratory quotient (CRQ) and a changed post-meal profile of CRQ (P=0.019). These changes reflected a significantly lower pre-meal utilization of carbohydrates in LE versus EE (P=0.006). LE also increased glucose area under curve above baseline by 46%, demonstrating decreased glucose tolerance (P=0.002). Changes in the daily profile of cortisol and Twrist were also found with LE blunting the cortisol profile, with lower morning and afternoon values, and suppressing the postprandial Twrist peak (P<0.05).
Eating late is associated with decreased resting-energy expenditure, decreased fasting carbohydrate oxidation, decreased glucose tolerance, blunted daily profile in free cortisol concentrations and decreased thermal effect of food on Twrist. These results may be implicated in the differential effects of meal timing on metabolic health.
ABSTRACT
The logarithmic extinction coefficient, c(H β), is usually derived using the H α/H β ratio for case B recombination and assuming standard values of electron density and temperature. However, ...the use of strong Balmer lines can lead us to selection biases when studying regions with different surface brightness, such as extended nebulae, with the use of single integral field spectroscopy observations, since, in some cases, the H α line can be saturated in moderate to long exposures. In this work, we present a method to derive extinction corrections based only on the weaker lines of He i, taking into account the presence of triplet states in these atoms and its influence on recombination lines. We have applied this procedure to calculate the extinction of different regions of the 30 Doradus nebula from MUSE integral-field spectroscopy data. The comparison between helium and hydrogen c(H β) determinations has been found to yield results fully compatible within the errors and the use of both sets of lines simultaneously reduces considerably the error in the derivation.
Coseismic landslides can destroy buildings, dislocate roads, sever pipelines, and cause heavy casualties. It is thus important but challenging to accurately map the hazards posed by coseismic ...landslides. Newmark's method is widely applied to assess the permanent displacement along a potential slide surface and model the coseismic response of slopes. This paper proposes an improved Newmark analysis for mapping the hazards of coseismic landslides by considering the roughness and effect of the size of the potential slide surfaces. This method is verified by data from a case study on the 2014 Mw 6.1 (the United States Geological Survey) Ludian earthquake in Yunnan Province, China. Permanent displacements due to the earthquake ranged from 0 to 122 cm. The predicted displacements were compared with a comprehensive inventory of landslides triggered by the Ludian earthquake to map the spatial variation in the hazards of coseismic landslides using the certainty factor model. The confidence levels of coseismic landslides indicated by the certainty factors ranged from −1 to 0.95. A hazard map of the coseismic landslide was generated based on the spatial distribution of values of the certainty factor. A regression curve relating the predicted displacement and the certainty factor was drawn, and can be applied to predict the hazards of coseismic landslides for any seismic scenario of interest. The area under the curve was used to compare the improved and the conventional Newmark analyses, and revealed the improved performance of the former. This mapping procedure can be used to predict the hazards posed by coseismic landslides, and provide guidelines for decisions regarding the development of infrastructure and post-earthquake reconstruction.
Context.
There are typically two different approaches to inferring the mass formation history (MFH) of a given galaxy from its luminosity in different bands. Non-parametric methods are known for ...their flexibility and accuracy, while parametric models are more computationally efficient.
Aims.
In this work we propose an alternative, based on a polynomial expansion around the present time, that combines the advantages of both techniques.
Methods.
In our approach, the MFH is decomposed through an orthonormal basis of
N
polynomials in lookback time. To test the proposed framework, synthetic observations are generated from models based on common analytical approximations (exponential, delayed-
τ
, and Gaussian star formation histories), as well as cosmological simulations for the Illustris-TNG suite. A normalized distance is used to measure the quality of the fit, and the input MFH is compared with the polynomial reconstructions both at the present time and through cosmic evolution. Our polynomial expansion is also compared with widely used parametric and non-parametric methods such as C
IGALE
and P
ROSPECTOR
.
Results.
The observed luminosities are reproduced with an accuracy of around 10 per cent for a constant star formation rate (
N
= 1) and better for higher-order polynomials. Our method provides good results on the reconstruction of the total stellar mass, the star formation rate, and even its first derivative for smooth star formation histories, but it has difficulties in reproducing variations on short timescales and/or star formation histories that peak at the earliest times of the Universe.
Conclusions.
The polynomial expansion appears to be a promising alternative to other analytical functions used in parametric methods, combining both speed and flexibility.
Fructooligosaccharides (FOS) are oligosaccharides that occur naturally in plants such as onion, chicory, garlic, asparagus, banana, artichoke, among many others. They are composed of linear chains of ...fructose units, linked by β (2-1) bonds. The number of fructose units ranges from 2 to 60 and often terminate in a glucose unit. Dietary FOS are not hydrolyzed by small intestinal glycosidases and reach the cecum structurally unchanged. There, they are metabolized by the intestinal microflora to form short-chain carboxylic acids, L -lactate, CO
2
, hydrogen and other metabolites. FOS have a number of interesting properties, including a low sweetness intensity; they are also calorie free, non-cariogenic and are considered as soluble dietary fibre. Furthermore, FOS have important beneficial physiological effects such as low carcinogenicity, a prebiotic effect, improved mineral absorption and decreased levels of serum cholesterol, triacylglycerols and phospholipids. Currently FOS are increasingly included in food products and infant formulas due to their prebiotic effect stimulate the growth of nonpathogenic intestinal microflora. Their consumption increases fecal bolus and the frequency of depositions, while a dose of 4–15 g/day given to healthy subjects will reduce constipation, considered one of the growing problems of modern society, and newborns during the first months of life.
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•A Group Contribution Method (GCM) based on molecular functionality is proposed.•Hydrocarbon absorption spectra in the MIR region are used to validate the GCM.•The GCM is also applied ...for unreported species MIR absorption spectra calculation.•The GCM-MIR is proposed to monitor FCC reaction extent for two model compounds.•Emulated GCM-MIR detection in the CREC Riser Simulator annulus shows its viability.
Hydrocarbon species concentrations in the gas phase are of critical importance to elucidate catalytic cracking kinetics and riser/downer fluid dynamics. In this respect, Mid-Infrared (MIR) spectroscopy provides a singular approach to monitor chemical species conversions at various reaction times. In the MIR, the Absorption Cross Section Coefficients and Integrated Absorption Band Intensities can be related to the number of C-H bonds present in the different chemical species. The proposed methodology is based on a Group Contribution Method (GCM), which accounts for the additive contribution of molecular functionalities related to the CH bonds present in hydrocarbons. This allows absorption spectra predictions in 3200–2800 cm−1 region. This Group Contribution Method can be applied in conjunction with a helium-neon (HeNe) laser, with a 2949.85 cm−1 wavenumber (3.39 µm wavelength). The technique is validated using both 1-hexene and 1,3,5-TIPB catalytic cracking data. The importance of the proposed method is shown in the context of using a CREC Riser Simulator, a mini-fluidized laboratory scale unit invented at CREC-UWO (de Lasa, 1991). Hydrocarbon species are MIR monitored in the outer CREC Riser Simulator annulus. The data obtained can be used to extrapolate gas phase hydrocarbon conversions and fluid molar densities in risers and downers. This information can be also used to accurately predict fluid dynamics in FCC catalytic cracking units.
Background
Treatment response for psoriasis is typically evaluated using clinical scores. However, patients can relapse after clinical clearance, suggesting persistent inflammation. Dermoscopy, ...reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) can non‐invasively improve treatment response assessment.
Objectives
To compare the clinical and non‐invasive microscopic features in a psoriatic target lesion treated with clobetasol cream or calcipotriol/betamethasone dipropionate foam (Cal/BD foam).
Methods
Prospective, unicentric, open, randomized clinical trial comparing clinical data total clinical score (TCS) and microscopic data (dermoscopy, RCM and OCT) in psoriasis patients treated with clobetasol or Cal/BD foam.
Results
We included 36 adult patients (22 men). At week 4, more patients treated with Cal/BD foam achieved TCS ≤1 than with clobetasol (63.2% vs. 18.8%, P = 0.016). Treatment satisfaction was higher with Cal/BD foam (P < 0.03). Microscopically, Cal/BD foam induced more reduction in epidermal thickness at week 4 (P < 0.049). Dilated horizontal blood vessels were more common with clobetasol than with Cal/BD foam at week 8 (69.2% vs. 31.2%, P = 0.159). If epidermal hyperplasia was noted at baseline, the response was poorer with clobetasol (P = 0.029).
Limitations
Small sample size, open study, imaging sampling bias.
Conclusion
Cal/BD foam is more effective than clobetasol, has better patient satisfaction and induces greater reduction in the hyperkeratosis/acanthosis, regardless of baseline epidermal hyperplasia.
Hepatocellular carcinoma (HCC) is the most common malignant neoplasm of the liver and one of the deadliest cancers worldwide. The identification of novel, highly specific and more sensitive ...biomarkers for HCC is crucial because existing ones are deficient and non-confirmatory without histological biopsy or imaging techniques.
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