272 research outputs found

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

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    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

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    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

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    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

    Implicancias ambientales de la deslignificación de pulpas kraft de eucalipto utilizando perácidos

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    Because of great environmental pressures, the cellulose industry has studied the potential of use of new bleaching agents among which peroxymonosulfuric acid and peracetic acid stand out. This survey summarizes the results of various laboratory investigations using peracids to delignify eucalyptus kraft pulps. The effect of a step using peroxymonosulfuric acid followed by a D-Eo-D sequence [free of elemental chlorine] was studied and compared with the use of peracetic acid and mixtures of these two acids. It was shown that a mixture of peroxymonosulfuric acid and peracetic acid reduced more lignin (measured as kappa index) than the individual peracids, and reduced more hexenuronic acid than peracetic acid with less degradation of the cellulose than with peroxymonosulfuric acid. This was explained on the basis of the electrophilic and nucleophilic properties of these acids that improved the delignification of eucalyptus kraft pulp. The effluents generated in these steps involving the peracids had greater color, chemical oxygen demand (COD), and total phenols correlating with the amount of lignin removed and the analyses of bioassays did not show acute toxicity from effluents coming from a peroxymonosulfuric acid step. The delignification with peracids may possibly reduce the use of chlorine dioxide in a sequence involving bleaching with elemental free chlorine (ECF), in this way reducing the concentration of organic chlorides (AOX) in the bleaching effluent

    Chenopodium quinoa Willd. (quinoa) grains: A good source of phenolic compounds

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    The ingestion of bioactive compounds has revealed health benefits, namely in the prevention and/or treatment of several diseases. This work aims to characterize the phenolic profile of three colour varieties of Chenopodium quinoa Willd. grains (black, red and white), and also evaluate their cytotoxic and antimicrobial activity. All varieties revealed the presence of phenolic compounds, namely, quercetin and kaempferol derivatives. In this study, quinoa grains did not reveal any anti-proliferative capacity in tumour cell lines, and, as expected, they were devoid of any toxicity. All of the analysed extracts possessed antibacterial and antifungal activities (inhibitory and bactericidal/fungicidal) against the microbial strains considered, exhibiting promising values of minimum bactericidal concentrations (mean MBC 0.153–0.916 mg/mL) and minimum fungicidal concentrations (mean MFC 0.211–0.884 mg/mL). Quinoa varieties represent a good source of bioactive compounds, interfering beneficially in the organism, specifically as antimicrobial agents. Thus, these extracts could be used in the development of bioactive ingredients.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020); FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E and TRANSCoLAB 0612_TRANS_CO_LAB_2_P; and L. Barros, R. Calhelha, and Gonzales-Barron thank the national funding by FCT, P.I., through the institutional scientific employment program contract. This work has also been supported by the Ministry of Education, Science and Technological Development of Republic of Serbia (451-03-68/2020-14/200007).info:eu-repo/semantics/publishedVersio

    Interactions, star formation and extended nebulae in SDSS type 2 quasars at 0.3<~ z <~ 0.6

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    We present long-slit spectroscopy and imaging data obtained with FORS2 on the Very Large Telescope of 13 optically selected type 2 quasars at z~0.3-0.6 from the original sample of Zakamska et al. (2003). The sample is likely to be affected by different selection biases. We investigate the evidence for: a) mergers/interactions b) star formation activity in the neighborhood of the quasars and c) extended emission line regions and their nature. Evidence for mergers/interactions is found in 5/13 objects. This is a lower limit for our sample, given the shallowness of most of our continuum images. Although AGN photoionization cannot be totally discarded, line ratios consistent with stellar photoionization are found in general in companion galaxies/knots/nuclei near these same objects. On the contrary, the gas in the neighborhood of the quasar nucleus shows line ratios inconsistent with HII galaxies and typical of AGN photoionized nebulae. A natural scenario to explain the observations is that star formation is ongoing in companion galaxies/knots/nuclei, possibly triggered by the interactions. These systems are, therefore, composite in their emission line properties showing a combination of AGN and star formation features. Extended emission line regions (EELRs) have been found in 7/13 objects, although this fraction might be higher if a complete spatial coverage around the quasars was performed. The sizes vary between few and up to 64 kpc. In general, the EELRs apparently consist of an extended nebula associated with the quasar. In at least one case the EELR is associated with ionized tidal features.Comment: Accepted for publication in MNRAS. 19 pages, 30 figure

    Draft genome sequence of the type strain of the sulfur-oxidizing acidophile, Acidithiobacillus albertensis (DSM 14366)

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    Abstract Acidithiobacillus albertensis is an extremely acidophilic, mesophilic, obligatory autotrophic sulfur-oxidizer, with potential importance in the bioleaching of sulfidic metal ores, first described in the 1980s. Here we present the draft genome sequence of Acidithiobacillus albertensis DSM 14366T, thereby both filling a long-standing gap in the genomics of the acidithiobacilli, and providing further insight into the understanding of the biology of the non iron-oxidizing members of the Acidithiobacillus genus. The assembled genome is 3,1 Mb, and contains 47 tRNAs, tmRNA gene and 2 rRNA operons, along with 3149 protein-coding predicted genes. The Whole Genome Shotgun project was deposited in DDBJ/EMBL/GenBank under the accession MOAD00000000

    Selected reactive oxygen species and antioxidant enzymes in common bean after Pseudomonas syringae pv. phaseolicola and Botrytis cinerea infection

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    Phaseolus vulgaris cv. Korona plants were inoculated with the bacteria Pseudomonas syringae pv. phaseolicola (Psp), necrotrophic fungus Botrytis cinerea (Bc) or with both pathogens sequentially. The aim of the experiment was to determine how plants cope with multiple infection with pathogens having different attack strategy. Possible suppression of the non-specific infection with the necrotrophic fungus Bc by earlier Psp inoculation was examined. Concentration of reactive oxygen species (ROS), such as superoxide anion (O2 -) and H2O2 and activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were determined 6, 12, 24 and 48 h after inoculation. The measurements were done for ROS cytosolic fraction and enzymatic cytosolic or apoplastic fraction. Infection with Psp caused significant increase in ROS levels since the beginning of experiment. Activity of the apoplastic enzymes also increased remarkably at the beginning of experiment in contrast to the cytosolic ones. Cytosolic SOD and guaiacol peroxidase (GPOD) activities achieved the maximum values 48 h after treatment. Additional forms of the examined enzymes after specific Psp infection were identified; however, they were not present after single Bc inoculation. Subsequent Bc infection resulted only in changes of H2O2 and SOD that occurred to be especially important during plant–pathogen interaction. Cultivar Korona of common bean is considered to be resistant to Psp and mobilises its system upon infection with these bacteria. We put forward a hypothesis that the extent of defence reaction was so great that subsequent infection did not trigger significant additional response
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