19 research outputs found

    1-(5-Hydroxy-1-phenyl-3-trifluoromethyl-1H-pyrazol-1-yl)ethanone

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    The crystal structure of the title compound, C12H9F3N2O2, contains two independent mol­ecules in the asymmetric unit. The mol­ecules are chemically identical but exhibit a significant difference in the dihedral angles between the mean planes of the phenyl and pyrazole rings, with values of of 11.62 (13) and 18.17 (11)°. Moreover, the trifluoro­methyl group in one of the mol­ecules shows rotational disorder of the F atoms, with site occupancy factors of 0.929 (6) and 0.071 (6). The hydroxyl group in each of the mol­ecules shows a strong intra­molecular hydrogen bond with the carbonyl O atom, forming a six-membered ring and forcing the formyl group and pyrazole ring to be coplanarshowing C—C—C—O torsion angles of ?0.3(5)o and 0.°. Weak inter­molecular C—H⋯O and C—H⋯F inter­actions contribute to the stabilization of the crystal packing

    2-Phenyl-5-(trifluoro­meth­yl)pyrazol-3(2H)-one

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    The title compound, C10H7F3N2O, is an analogue of pyrazolone derivatives with potential analgesic and anti-inflammatory properties. Its mol­ecular structure consists of phenyl and pyrazol-3(2H)-one units with a dihedral angle between the mean planes of the rings of 33.0 (1)°. The crystal structure is stabilized by an inter­molecular hydrogen bond between the N—H group and the carbonyl O atom of the pyrazol-3(2H)-one ring which links the mol­ecules into supra­molecular C(5) chains along [001] and by weak π–π stacking inter­actions between the phenyl rings [centroid-centroid distance = 3.881 (2) Å]. The F atoms are disordered over two positions with refined site occupancies of 0.768(11) and 0.232(11)

    Significance of K-Ar dating of very low-grade metamorphism in Triassic-Jurassic pelites from the Coastal Range of central Chile

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    El artículo original ha sido publicado por la Mineralogical Society disponible en: http://www.minersoc.org/pages/e_journals/clay.htmlK-Ar isotopic dating of very low-grade metamorphism affecting Triassic-Jurassic rocks in the Coastal Range of central Chile was carried out on whole rocks and their <2 mm size fractions. In the study area, a regional-burial low-grade metamorphism at anchizone conditions (T ≤ 190ºC) and low-pressure conditions (P ≥1.3 kbar) has been described. Observed temperatures are related to a contact metamorphism produced by nearby Jurassic intrusions, with a P-T estimate at the immediate contact zone of ~650-690ºC and 4 kbar. The whole-rock K-Ar age of 174?5 Ma is interpreted as belonging to the contact metamorphism due to the intrusion of Jurassic plutons (165±5 Ma to 175±5 Ma). A time-interval of ~20 Ma between the diagenesis (206 Ma) and the anchizonal very low-grade metamorphism (181-184 Ma) is obtained, and a rate of subsidence of ~120 m/Ma is proposed for these Triassic-Jurassic basins. A thermal influence on the burial, very low-grade, regional metamorphism is invoked.Departamento de Mineralogía y Petrologí

    Glaciation Effects on the Phylogeographic Structure of Oligoryzomys longicaudatus (Rodentia: Sigmodontinae) in the Southern Andes

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    The long-tailed pygmy rice rat Oligoryzomys longicaudatus (Sigmodontinae), the major reservoir of Hantavirus in Chile and Patagonian Argentina, is widely distributed in the Mediterranean, Temperate and Patagonian Forests of Chile, as well as in adjacent areas in southern Argentina. We used molecular data to evaluate the effects of the last glacial event on the phylogeographic structure of this species. We examined if historical Pleistocene events had affected genetic variation and spatial distribution of this species along its distributional range. We sampled 223 individuals representing 47 localities along the species range, and sequenced the hypervariable domain I of the mtDNA control region. Aligned sequences were analyzed using haplotype network, Bayesian population structure and demographic analyses. Analysis of population structure and the haplotype network inferred three genetic clusters along the distribution of O. longicaudatus that mostly agreed with the three major ecogeographic regions in Chile: Mediterranean, Temperate Forests and Patagonian Forests. Bayesian Skyline Plots showed constant population sizes through time in all three clusters followed by an increase after and during the Last Glacial Maximum (LGM; between 26,000–13,000 years ago). Neutrality tests and the “g” parameter also suggest that populations of O. longicaudatus experienced demographic expansion across the species entire range. Past climate shifts have influenced population structure and lineage variation of O. longicaudatus. This species remained in refugia areas during Pleistocene times in southern Temperate Forests (and adjacent areas in Patagonia). From these refugia, O. longicaudatus experienced demographic expansions into Patagonian Forests and central Mediterranean Chile using glacial retreats

    Functional Alterations Induced by Prenatal Malnutrition in Callosal Connections and Interhemispheric Asymmetry as Revealed by Transcallosal and Visual Evoked Responses in the Rat

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    It is known that nutritional restriction during gestation affects the growth of the corpus callosum. The present study was designed to evaluate whether prenatal malnutrition may alter, in the rat, the normal pattern of functional callosal interhemispheric connections of the visual cortex. Since callosal development has been associated with brain lateralization, the effect of malnutrition during gestation on the normal asymmetry of visual cortical evoked responses was also studied. Prenatal malnutrition was induced by restricting food consumption by pregnant rats (10 g daily) from Day 8 post-conception to parturition. Results of experiments performed on 45- to 50-day-old offspring showed that the starvation treatment (i) reduced both the peak-to-peak amplitude and the extent of the projecting field of transcallosal evoked responses, and (ii) abolished the normal brain interhemispheric asymmetry of visual evoked responses. These effects are discussed in relationship to regressive event

    Microhabitat and associated biota of abalone juveniles, Haliotis fulgens and H. corrugata, in Bahía Tortugas, Baja California Sur, Mexico

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    Abalone is an important economical resource on the west coast of Baja California. The most important species in this fishery are green and pink abalone (Haliotis fulgens and H. corrugata, respectively). Overfishing has been implicated in the decline of the Mexican abalone fishery. Among the population parameters, recruitment is a highly variable event. To obtain a better understanding of the ecology of abalone juvenile recruitment, the physical and biological characteristics of the microhabitat of juveniles of green and pink abalone were studied at Bahía Tortugas, Baja California Sur (Mexico), during autumn and spring from 1996 to 1998. Two abalone reefs with different depth, relief and wave exposure were surveyed: Clam Bay, with depths of 0.5 to 5 m, and Morro de Adentro, with depths of 6 to 12 m. Four different bottom types were recognized: (a) sheltered and low relief bottom, (b) semiexposed and moderate relief bottom, (c) exposed and high relief bottom, and (d) exposed and moderate relief bottom. Juveniles of green and pink abalone from 3 to 13 mm shell length were observed under small rocks, pebbles and flat stones no longer than 15|00E2|??20 cm, always covered with crusts of coralline algae. Several tiny juveniles of Fisurella, Stenoplax, and Crepipatella of similar sizes (5–10 mm) shared the microhabitat. Juveniles between 15 and 90 mm shell length were found under flat, rhombic or irregular-shaped rocks (20–110 mm length), most of them deployed in imbricate arrangement. Abalone juveniles shared this microhabitat with bryozoans, sponges, ascidians, chitons, and annelids. Bottoms with imbricate arrangement, low wave exposure, and the low depth of Clam Bay were favorable for the high occurrence of juveniles of H. fulgens. Juveniles of H. corrugata showed a high occurrence in exposed and deeper zones of Morro de Adentro

    Draft genome sequences of Cylindrospermopsis raciborskii strains CS-508 and MVCC14, isolated from freshwater bloom events in Australia and Uruguay

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    Abstract Members of the genus Cylindrospermopsis represent an important environmental and health concern. Strains CS-508 and MVCC14 of C. raciborskii were isolated from freshwater reservoirs located in Australia and Uruguay, respectively. While CS-508 has been reported as non-toxic, MVCC14 is a saxitoxin (STX) producer. We annotated the draft genomes of these C. raciborskii strains using the assembly of reads obtained from Illumina MiSeq sequencing. The final assemblies resulted in genome sizes close to 3.6 Mbp for both strains and included 3202 ORFs for CS-508 (in 163 contigs) and 3560 ORFs for MVCC14 (in 99 contigs). Finally, both the average nucleotide identity (ANI) and the similarity of gene content indicate that these two genomes should be considered as strains of the C. raciborskii species

    Impacts of diffuse urban stressors on stream benthic communities and ecosystem functioning: A review

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    Catchment urbanisation results in urban streams being exposed to a multitude of stressors. Notably, stressors originating from diffuse sources have received less attention than stressors originating from point sources. Here, advances related to diffuse urban stressors and their consequences for stream benthic communities are summarised by reviewing 92 articles. Based on the search criteria, the number of articles dealing with diffuse urban stressors in streams has been increasing, and most of them focused on North America, Europe, and China. Land use was the most common measure used to characterize diffuse stressor sources in urban streams (70.7 % of the articles characterised land use), and chemical stressors (inorganic nutrients, xenobiotics, metals, and water properties, including pH and conductivity) were more frequently reported than physical or biological stressors. A total of 53.3 % of the articles addressed the impact of urban stressors on macroinvertebrates, while 35.9 % focused on bacteria, 9.8 % on fungi, and 8.7 % on algae. Regarding ecosystem functions, almost half of the articles (43.5 %) addressed changes in community dynamics, 40.3 % addressed organic matter decomposition, and 33.9 % addressed nutrient cycling. When comparing urban and non-urban streams, the reviewed studies suggest that urbanisation negatively impacts the diversity of benthic organisms, leading to shifts in community composition. These changes imply functional degradation of streams. The results of the present review summarise the knowledge gained to date and identify its main gaps to help improve our understanding of urban streams.This study has received funding from the Iberian Association of Limnology (AIL) through the project URBIFUN (Urbanization effects on the relationship between microbial biodiversity and ecosystem functioning), awarded to Míriam Colls and Ferran Romero. Authors thank as well the Basque Government (Consolidated Research Group IT951-16) and the MERLIN project 101036337 – H2020-LC-GD-2020/H2020-LC-GD-2020-3.info:eu-repo/semantics/publishedVersio
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