Feeding ecology of the Ruivaco Achondrostoma oligolepis, a Portuguese endemic cyprinid fish

This study assessed the feeding ecology of the ruivaco Achondrostoma oligolepis, a Portuguese endemic resident cyprinid fish whose dietary habits are virtually unknown. Samples were taken seasonally in three medium-sized rivers representing a gradient of temporality. The stomach contents of 97 individuals (42-126 mm total length, TL) were analysed. Although there was no significant overall variation in diet composition between rivers, differences were found among seasons. A broad range of food categories was identified, although a smaller subset of primarily detritus (77.6 %) and plant material (18.4 %) constituted the base diet. Of the animal prey, Coleoptera and Diptera were the most prevalent, occurring in 13.2 % and 9.8 % of the fish, respectively, and were consumed mainly in the spring. Based on the observed diet composition and feeding strategy, the ruivaco could be considered a generalist, foraging on the most abundant and available preyEste estudio evaluó la ecología alimentaria del ruivaco (Achondrostoma oligolepis), un ciprínido endémico de Portugal cuyos hábitos alimenticios son prácticamente desconocidos. Las muestras fueron recogidas estacionalmente, en tres ríos medianos representando un gradiente de temporalidad. Los contenidos estomacales de 97 individuos (42-126 mm de longitud total, LT) fueron analizados. Aunque en general no hubo variación significativa en la composición de la dieta entre ríos, sí se encontraron diferencias entre las estaciones. Se identificó una amplia gama de categorías de alimentos, aunque un subconjunto más pequeño conformó la base de la dieta, encontrándose principalmente dominada por detritus (77.6 %) y material vegetal (18.4 %). Los coleópteros y dípteros fueron los grupos más frecuentes entre las presas animales, siendo encontrados en el 13.2 % y el 9.8 % de los peces respectivamente, y consumidos principalmente en primavera. Con base en la composición de la dieta y en la representación de la estrategia trófica, el ruivaco puede ser considerado como generalista, alimentándose de las presas más abundantes y disponible

Assessing the influence of the carbon oxidation-reduction state on organic pollutant biodegradation in algal-bacterial photobioreactors

The influence of the carbon oxidation-reduction state (CORS) of organic pollutants on their biodegradation in enclosed algal-bacterial photobioreactors was evaluated using a consortium of enriched wild-type methanotrophic bacteria and microalgae. Methane, methanol and glucose (with CORS -4, -2 and 0, respectively) were chosen as model organic pollutants. In the absence of external oxygen supply, microalgal photosynthesis was not capable of supporting a significant methane and methanol biodegradation due to their high oxygen demands per carbon unit, while glucose was fully oxidized by photosynthetic oxygenation. When bicarbonate was added, removal efficiencies of 37¿±¿4% (20 days), 65¿±¿4% (11 days) and 100% (2 days) were recorded for CH(4,) CH(3)OH and C(6)H(12)O(6), respectively due to the additional oxygen generated from photosynthetic bicarbonate assimilation. The use of NO(3)(-) instead of NH(4)(+) as nitrogen source (N oxidation-reduction state of +5 vs. -3) resulted in an increase in CH(4) degradation from 0 to 33¿±¿3% in the absence of bicarbonate and from 37¿±¿4% to 100% in the presence of bicarbonate, likely due to a decrease in the stoichiometric oxygen requirements and the higher photosynthetic oxygen production. Hypothetically, the CORS of the substrates might affect the CORS of the microalgal biomass composition (higher lipid content). However, the total lipid content of the algal-bacterial biomass was 19¿±¿7% in the absence and 16¿±¿2% in the presence of bicarbonat

Reproductive capacity of the red cusk-eel genypterus chilensis (Guichenot, 1848) in captivity

Indexación: Scopus.This work was supported by the FONDEF Project D06I 1024 “Development of technologies for the production of red cusk-eel fingerlings (Genypterus chilensis)”.Genypterus chilensis is a marine fish of high gastronomic demand, whose capture has declined in recent years due to overfishing. In the development of the farming technology, high mortalities were obtained during egg incubation. The objective of this study is to contribute to the knowledge of fecundity and eggs viability of G. chilensis in captivity. The spawns of G. chilensis were analyzed over a period of 2 years and 3 months. The total fecundity was estimated by counting the masses and eggs produced monthly throughout the period. The results confirm that G. chilensis is a partial spawner, since a female may more than two masses of eggs per day, due to a large amount of mass spawned per season (621 average). The total production of masses of the Farming Centre during the period was 2,290; of these, only 7% (166) corresponding to 15,330,517 eggs were incubated. Because of its high fecundity, G. chilensis produces numerous masses of eggs, of which only a small percentage reaches incubation, as well as it occurs in other marine fish. © 2018, Escuela de Ciencias del Mar. All rights reserved.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0718-560X201800020048

Exploring high temperature magnetic order in CeTi_1-xSc_xGe

Most of magnetic transitions related to Ce ordering are found below T_ord~12K. Among the few cases exceeding that temperature, two types of behaviors can be distinguished. One of them is related to the rare cases of Ce binary compounds formed in BCC structures, with a quartet ground state, whose degeneracy is reduced by undergoing different types of transitions mostly structural. The other group shows evidences of itinerant character with the outstanding example of CeRh_3B_2 showing the highest T_ord=115K. The second highest ordering temperature has been reported for CeScGe with T_ord=47K, but the nature of this magnetic state has not been investigated very deeply. In order to shed more light into this unusual high temperature ordering we studied the structural, magnetic, transport and thermal properties of CeTi_1-xSc_xGe alloys in the stability range of the CeScSi-type structure 0.25<x<1 This system presents a rich variety of magnetic behaviors along this concentration range, with the magnetic ordering growing from ferromagnetic (FM) T_C~7K up to an antiferromagnetic (AFM) transition at T_N=47K. The different regions show the following characteristics: i) on the Ti rich side (0.25<x<0.50) it exhibits a FM ground state (GS) with large saturation magnetization values M_sat up to ~1.15 mu_B. ii) Around x=0.60, the first crystal electric field excited doublet starts to contribute to the GS magnetic properties. Furthermore an AFM component with a connected metamagnetic transition appears. iii) At x=0.65 a clear change in the GS nature is associated to a critical point above which the GS properties can be described like for an itinerant system (with decreasing M_sat) and an effective GS degeneracy N_eff=4. iv) For x>0.65, the magnetic phase boundary splits into two transitions, with an intermediate phase presenting incommensurate spin density waves features.Comment: 8 pages, 10 figure

A crowdsourcing-based system for monitoring em radiation exposure in Chile

Indexación: Scopus.Public concern about the possible effects on health due to electromagnetic (EM) radiation exposure has led to the definition of regulations worldwide. In Chile, the so-called "Ley de Antenas" provides a regulatory framework that establishes limits and special conditions in this regard. Although the official record of measurements is available in a public information portal, this approach is not scalable and intuitive enough for all interested users. This paper propose a participatory measurement system to extend the monitored areas based on the concern of citizens themselves. © 2018 CEUR-WS. All rights reserved.http://ceur-ws.org/Vol-2178/SSN2018_paper_7.pd

Quenching of excited carbonyl triplets by benzene derivatives

Se ha medido la velocidad de desactivación de tripletes carbonilicos (biacetilo, bencilo, benzofenona y 4-metil-2-pentanona) por una serie d,e derivados del benceno. Los resultados pueden ser interpretados por un mecanismo de transferencia de carga. Los compuestos con hidrógenos lábiles (i.e.cumeno) muestran una mayor reactividad. La abstracción de hidrógeno ocurre desde el complejo de transferencia de carga. La desactivación del triplete de la 4-metil-2-pentanona fue medida entre - 5 y 70°C. Las energias de activación obtenidas variaron entre 8.1 kcal (para el cumeno) y 10 kcal (para el benceno)

Conjunctival Short-term Evolution after Pterygium Excision

Purpose To analyze conjunctival cytological features 1 month after pterygium excision using limbo-conjunctival autograft (LCA) with and without intraoperative mitomycin C and to assess tissue short-term evolution in both situations.; Methods Fifty-nine primary nasal pterygia from 59 patients were excised with LCA. Twenty-nine were treated with intraoperative mitomycin C 0.02% (MMC+) and 30 were treated without it (MMC-). Impression cytology was performed in nasal and temporal conjunctiva before and 1 month after the excision. Goblet cell density (GCD) and nucleus-to-cytoplasm nongoblet epithelial cell ratio were quantified.; Results Surgical strategy comparisons (intergroup comparisons): All the preoperative data were, in mean, within the reference range, except for a slight goblet cell hyperplasia in the area of the lesion in MMC+ but no significant differences were found between the groups (p = 0.079 for GCD and p = 0.245 for nucleus-to-cytoplasm ratio; analysis of variance). Clinically relevant differences after surgery were only shown in nasal GCD that was significantly lower in MMC+ than in MMC- (p = 0.000; analysis of variance), with the mean value in MMC+ slightly below normal values whereas that in MMC- remained normal. Tissue evolution (intragroup comparisons): No clinically relevant changes were found in MMC-. Data from MMC+ displayed no changes 1 month after surgery, except for nasal GCD that showed a significant reduction (p = 0.000; paired t test). Nevertheless, this GCD decrease was more modest than that previously described using mitomycin C without autograft, because in the present study, nasal GCD was not lower but similar to postoperative temporal data of the same eye (p = 0.164; paired t test).; Conclusions Limbo-conjunctival autograft is a good technique for conjunctiva early recovery. When mitomycin C was added, the GCD reduction was lower than described using other surgical techniques. Mitomycin C, in optimal concentration and exposure, associated with LCA could be a good clinical option to minimize pterygium recurrence.Postprint (author's final draft