Mulching and seeding treatments for post-fire stabilization techniques in Laza (NW Spain): medium-term effects on soil quality and effectiveness

The impact of fire and different post-fire stabilisation treatments like mulching and seeding on some selected physical, chemical biochemical and microbiological properties as well as the efficacy of these treatments on control of post-fire erosion was evaluated in a burnt area affected by a high severity wildfire located in Laza (NW Spain). Soil samples were collected from the A horizon (0-2 cm) of the burnt soil 8 and 12 months after the wildfire as well as from the unburnt soil located in an adjacent plot used as control; sediments were periodically collected after precipitation events in the burnt soil with and without different post-fire stabilisation treatments. The results clearly showed that a significant medium-term impact of the wildfire on most soil properties analyzed was still observed 12 months after the fire event and that mulching and seeding treatments did not affect the overall soil quality (physical, chemical, biochemical and microbiological properties) of this burned soil. Sediments data indicated that both stabilisation treatments were effective to control post-fire erosion since, compared to the burnt control, soil losses were reduced by 85% in the mulching treatment and by 30% in the seeding treatment

PopStar Evolutionary Synthesis Models II: Optical emission-line spectra from Giant H{\sc ii} regions

This is the second paper of a series reporting the results from the PopStar evolutionary synthesis models. Here we present synthetic emission line spectra of H{\sc ii} regions photoionized by young star clusters, for seven values of cluster masses and for ages between 0.1 and 5.2 Myr. The ionizing Spectral Energy Distributions (SEDs) are those obtained by the PopStar code \citep*{mgb09} for six different metallicities, with a very low metallicity set, Z=0.0001, not included in previous similar works. We assume that the radius of the H{\sc ii} region is the distance at which the ionized gas is deposited by the action of the mechanical energy of the winds and supernovae from the central ionizing young cluster. In this way the ionization parameter is eliminated as free argument, since now its value is obtained from the cluster physical properties (mass, age and metallicity) and from the gaseous medium characteristics (density and abundances). We discuss our results and compare them with those from previous models and also with a large and data set of giant H{\sc ii} regions for which abundances have been derived in a homogeneous manner. The values of the [OIII] lines (at $\lambda\lambda$ 4363, 4959, 5007\AA) in the lowest metallicity nebulae are found to be very weak and similar to those coming from very high metallicity regions (solar or over-solar). Thus, the sole use of the oxygen lines is not enough to distinguish between very low and very high metallicity regions. In these cases we emphasize the need of the additional support of alternative metallicity tracers, like the [SIII] lines in the near-\textit{IR}.Comment: 20 pages, 26 figures, accepted for publication in MNRAS Main Journa

Recovery of a soil under different vegetation one year after a high intensity wildfire

Studies on soil recovery in fragile ecosystems following high intensity wildfires are scarce. The aim of the present investigation is to evaluate the impact of a high intensity wildfire in an ecosystem under different vegetation (shrubland and pinewood) located at Vilardevós (Galicia, NW Spain) and highly susceptible to suffer soil erosion due to the steep relief and high erositivity of the rainfall. Soil samples were collected from the A horizon (0-5 cm) 1 year after the fire and soil quality was evaluated by analysis of several physical, chemical and biochemical properties measured in the fraction < 2 mm. The results showed marked effects of the wildfire on most properties analyzed even 1 year after the fire; however, a different effect both in the trend (positive, negative) and magnitude were observed, depending on the soil property analyzed. In general, the sensitivity to detect fire induced changes followed the order: biochemical properties > chemical properties > physical properties. The data also showed that the fire impact was different depending on the soil vegetation considered (shrubland and pinewood). Moreover, the data confirmed the slow soil recovery in this fragile ecosystem and, therefore, the need of adopting post-fire stabilisation and rehabilitation treatments in order to minimize the post-fire erosion and soil degradation

The evolution of H{\sc ii} galaxies: Testing the bursting scenario through the use of self-consistent models

We have computed a series of realistic and self-consistent models of the emitted spectra of H{\sc ii} galaxies. Our models combine different codes of chemical evolution, evolutionary population synthesis and photoionization. The emitted spectrum of H{\sc ii} galaxies is reproduced by means of the photoionization code CLOUDY, using as ionizing spectrum the spectral energy distribution of the modelled H{\sc ii} galaxy, which in turn is calculated according to a Star Formation History (SFH) and a metallicity evolution given by a chemical evolution model that follows the abundances of 15 different elements. The contribution of emission lines to the broad-band colours is explicitly taken into account. The results of our code are compared with photometric and spectroscopic data of H{\sc ii} galaxies. Our technique reproduces observed diagnostic diagrams, abundances, equivalent width-colour and equivalent width-metallicity relations for local H{\sc ii} galaxies.Comment: 13 figures and 2 tables, accepted for publication in MNRAS Main Journa

Serum levels of caspase-cleaved cytokeratin-18 and mortality are associated in severe septic patients: Pilot study

Objective: Apoptosis is increased in sepsis. Cytokeratin 18 (CK-18), a protein of the intermediate filament group present in most epithelial and parenchymal cells, is cleaved by the action of caspases and released into the blood as caspase-cleaved CK (CCCK)-18 during apoptosis. Circulating levels of CCCK-18 have scarcely been explored in septic patients. In one study with 101 severe septic patients, the authors reported higher serum CCCK-18 levels in non-survivors than in survivors; however, the sample size was too small to demonstrate an association between serum CCCK-18 levels and early mortality and whether they could be used as a biomarker to predict outcomes in septic patients. Thus, these were the objectives of this study with a large series of patients. Methods: We performed a prospective, multicenter, observational study in six Spanish Intensive Care Units with 224 severe septic patients. Blood samples were collected at the time that severe sepsis was diagnosed to determine serum levels of CCCK-18, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-10. The end point was 30-day mortality. Results: Non-surviving patients (n = 80) showed higher serum CCCK-18 levels (P391 u/L were associated with 30-day survival (Odds ratio = 2.687; 95% confidence interval = 1.449-4.983; P = 0.002), controlling for SOFA score, serum lactic acid levels and age. Kaplan-Meier survival analysis showed that the risk of death in septic patients with serum CCCK-18 levels >391 u/L was higher than in patients with lower values (Hazard Ratio = 3.1; 95% CI = 1.96-4.84; P<0.001). Serum CCCK-18 levels were positively associated with serum levels of IL-6 and lactic acid, and with SOFA and APACHE scores. Conclusions: The major novel finding of our study, the largest cohort of septic patients providing data on circulating CCCK-18 levels, was that serum CCCK-18 levels are associated with mortality in severe septic patients

Pogonias courbina

This demersal species inhabits and forms seasonal spawning aggregations in shallow coastal waters and estuaries from southeastern Brazil to Argentina. It is a relatively long-lived, large-bodied species that canattain over 140 cm in length and 40 kg in weight and reach over 50 years in age. The estimated generation length is 28 years. It is targeted by commercial, artisanal and recreational fisheries throughout its range. Fisheries targeted spawning migrations in the Patos Lagoon estuary in southern Brazil at a high level from the 1940s to early 1980s, and landings have declined by 88% since 1982, orover the past 37 years. After these four decades of exploitation, only juveniles and small-sized adults are currently captured in the fishery. In Uruguay and Argentina, fishing effort primarily targets spawning aggregations in the La Plata River estuary. Landings in this fishery increased by 260% since 2000, or overthe past 19 years, as compared to landings in the period from 1975-1999. The current absence of large individuals in the La Plata River commercial catch and anecdotal observations of declines by Argentines portfishers, strongly implies that a truncation in age structure and a significant decline in abundance occurred.This species has intrinsic characteristics, including large body size, long longevity and high vulnerability to capture during predictable spawning/feeding migrations or aggregations, that cause it to be susceptible to large population declines under exploitation. However, its high fecundity and early age at© The IUCN Red List of Threatened Species: Pogonias courbina , published in 2020.https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T159145751A159145756.en1maturity (5-10% of the longevity) favours its resilience to exploitation under adequate fisheries management. The large decline in the southern Brazil fishery that targets this species was caused by years of intense fishing pressure, and that stock has not recovered. This is a clear warning that the fishery operating in La Plata estuary will follow the same path of decline unless urgent and drastic management measures are not implemented in the near future. Based on fisheries data and catch observations over time, it is inferred this species has undergone global-level declines of at least 30-40%over the past one and half generation lengths (about 42 years), and due to insufficient conservation measures, this decline is expected to continue over the next one and half generation lengths. Therefore,it is listed as Vulnerable A2bd+4bd with a strong recommendation to improve fisheries monitoring and management.Fil: Haimovici, M. Universidade Federal Do Rio Grande.; BrasilFil: Chao, L.. National Museum Of Marine Biology And Aquarium In Taiwa; República de ChinaFil: Vieira, J.P.. Universidade Federal Do Rio Grande.; BrasilFil: Buratti, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Irigoyen, A.. No especifíca;Fil: Riestra, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Landaeta, M.. Universidad de Valparaíso; ChileFil: Hüne, M.. Universidad Austral de Chile; Chil

Modal analysis of β-Ga₂O₃:Cr widely tunable luminescent optical microcavities

Optical microcavities are key elements in many photonic devices, and those based on distributed Bragg reflectors (DBRs) enhance dramatically the end reflectivity, allowing for higher quality factors and finesse values. Besides, they allow for wide wavelength tunability, needed for nano-and microscale light sources to be used as photonic building blocks in the micro- and nanoscale. Understanding the complete behavior of light within the cavity is essential to obtaining an optimized design of properties and optical tunability. In this work, focused ion-beam fabrication of high refractive-index contrast DBR-based optical cavities within Ga₂O₃:Cr microwires grown and doped by the vapor-solid mechanism is reported. Room-temperature microphotoluminescence spectra show strong modulations from about 650 nm up to beyond 800 nm due to the microcavity resonance modes. Selectivity of the peak wavelength is achieved for two different cavities, demonstrating the tunability of this kind of optical system. Analysis of the confined modes is carried out by an analytical approximation and by finite-difference-time-domain simulations. A good agreement is obtained between the reflectivity values of the DBRs calculated from the experimental resonance spectra, and those obtained by finite-difference-time-domain simulations. Experimental reflectivities up to 70% are observed in the studied wavelength range and cavities, and simulations demonstrate that reflectivities up to about 90% could be reached. Therefore, Ga₂O₃:Cr high-reflectivity optical microcavities are shown as good candidates for single-material-based, widely tunable light emitters for micro- and nanodevices