29 research outputs found

    Regular phantom black hole gravitational lensing

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    We study regular and asymptotically flat phantom black holes as gravitational lenses. We obtain the deflection angle in both the weak and the strong deflection limits, from which we calculate the positions, magnifications, and time delays of the images. We compare our results with those corresponding to the Schwarzschild solution and to the vacuum Brans-Dicke black hole.Comment: 14 pages, 4 figures; v2: improved and extended version, new references added. Accepted for publication in Phys. Rev.

    Strong deflection lensing by charged black holes in scalar-tensor gravity

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    We examine a class of charged black holes in scalar-tensor gravity as gravitational lenses. We find the deflection angle in the strong deflection limit, from which we obtain the positions and the magnifications of the relativistic images. We compare our results with those corresponding to the Reissner-Norstrom spacetime and we analyze the observational aspects in the case of the Galactic supermassive black hole.Comment: 12 pages, 3 figures; v2: improved version, new references adde

    Gravitational lensing by massless braneworld black holes

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    In this paper, we study massless braneworld black holes as gravitational lenses. We find the weak and the strong deflection limits for the deflection angle, from which we calculate the positions and magnifications of the images. We compare the results obtained here with those corresponding to Schwarzschild and Reissner-Nordstrom spacetimes, and also with those found in previous works for some other braneworld black holes.Comment: 12 pages, 4 figures; v3: typos corrected; 1 reference update

    Ceratium furcoides (Levander) Langhans in reservoirs at the Ebro watershed, Spain and Sao Paulo state, Brazil

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    This study compares the morphological characteristics of the dinoflagellate Ceratium furcoides from three Ebro basin reservoirs (Spain) and from six reservoirs at São Paulo state (Brazil) with the aim to identify the distinct morphotypes of Ceratium furcoides in Spain and Brazil. We studied the physical and chemical variables to determine the trophic state of each reservoir. Unlike Ceratium hirundinella, Ceratium furcoides is not a frequent species within the plankton community at Ebro Basin reservoirs, however, this species has been responsible of one monospecific bloom at El Val reservoir. Nevertheless, both Ceratium species are considered invasive in South America. Ceratium furcoides has displaced C. hirundinella at São Paulo state reservoirs, reaching high densities, to the extent of forming monospecific blooms. Morphometric analysis was performed by optic and electronic microscopy (DIC and SEM respectively). The analysis shows significant differences in: i) total cell length, ii) horns length and iii) presence or absence of a fourth horn. While the microscopic study allows differentiating morphotypes according to the reservoir typology, a deeper study using molecular genetic techniques on the different populations of C. furcoides would allow to know better the relationship between the dinoflagellate dynamics and the reservoirs trophic states

    Gravitational lensing by a regular black hole

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    In this paper, we study a regular Bardeen black hole as a gravitational lens. We find the strong deflection limit for the deflection angle, from which we obtain the positions and magnifications of the relativistic images. As an example, we apply the results to the particular case of the supermassive black hole at the center of our galaxy.Comment: 10 pages, 4 figures. v2: Improved version, new references adde

    Flourishing in subterranean ecosystems: Euro-Mediterranean Plusiocampinae and tachycampoids (Diplura, Campodeidae)

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    Este artículo contiene 138 páginas, 213 figuras, 14 tablas.Diplura is a group of entognathous hexapods, often considered a sister group to insects. They play an important role in recycling organic matter in soil and subterranean terrestrial ecosystems. The Campodeidae is the most diverse family, divided into four subfamilies. The subfamily Plusiocampinae has a subterranean life-style with many species distributed in the Euro-Mediterranean area. The incertae sedis tachycampoids (“lignée Tachycampoïde”) is a group within the family Campodeidae that share with the Plusiocampinae a strong preference for subterranean habitats and several morphological characters, such as slender body shape, elongated appendages, considerable increment in the number of antennomeres and cercal articles, and complexity of sensorial structures. The present monograph provides a taxonomic revision of the subfamily Plusiocampinae and the genera belonging to the tachycampoid lineage from Europe and the Mediterranean region. It comprises detailed morphological descriptions and illustrations together with data on the habitats and distributions of 87 species, 10 subspecies and 11 affinis forms. Seven new species are described among those, namely: Plusiocampa (Plusiocampa) apollo Sendra, Giachino & Vailati sp. nov., P. (P.) chiosensis Sendra & Gasparo sp. nov., P. (P.) dublanskii Sendra & Turbanov sp. nov., P. (P.) hoffmanni Sendra & Paragamian sp. nov., P. (P.) rhea Sendra sp. nov., P. (P.) ternovensis Sendra & Borko sp. nov. and P. (Venetocampa) ferrani Sendra & Delić sp. nov.DS’s field trips were funded by the Serbian Ministry of Education, Science and Technology (Grant 173038); KP was partially funded by the HISR project “Conservation of the Cave Fauna of Greece” funded by the MAVA Foundation and WWF Greece; PMG and DV carried out sampling in Greece using permits from the Ministry of Environment no. 124085/1362/2015, 135366/373/2016 and 166238/248/2018; IT was funded within the framework of the state assignment of FASO Russia (themes no. АААА-А18-118012690106-7 and АААА-А18-118012690105), supported in part by RFBR (project no. 17-54-40017Абх_а); sampling efforts by AF and colleagues resulted from various projects on the evolution of cave fauna diversity, some of them funded by the German Research Foundation, DFG (DFG FA 1042/1-1 and DFG BA 2152/14-1); PMG and DV were partly supported by the program “Research Missions in the Mediterranean Basin” sponsored by the World Biodiversity Association onlus XLI contribution; ASPSR was supported by a research grant (15471) from Villum Fonden.Peer reviewe

    Sex difference and intra-operative tidal volume: Insights from the LAS VEGAS study

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    BACKGROUND: One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES: The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING: This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES: Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg-1 or less predicted bodyweight (PBW). A VT was deemed 'default' if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS: This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg-1 PBW, P < 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P < 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION: In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, NCT01601223
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