2,826 research outputs found

    Measuring disturbance at a swift breeding colonies due to the visual aspects of a drone: a quasi-experiment study

    Get PDF
    There is a growing body of research indicating that drones can disturb animals. However, it is usually unclear whether the disturbance is due to visual or auditory cues. Here, we examined the effect of drone flights on the behaviour of great dusky swifts Cypseloides senex and white-collared swifts Streptoprocne zonaris in two breeding sites where drone noise was obscured by environmental noise from waterfalls and any disturbance must be largely visual. We performed 12 experimental flights with a multirotor drone at different vertical, horizontal and diagonal distances from the colonies. From all flights, 17% caused  50 m and that recreational flights should be discouraged or conducted at larger distances (e.g. 100 m) in nesting birds areas such as waterfalls, canyons and caves

    Phylogenetic Distribution of Fungal Sterols

    Get PDF
    BACKGROUND: Ergosterol has been considered the "fungal sterol" for almost 125 years; however, additional sterol data superimposed on a recent molecular phylogeny of kingdom Fungi reveals a different and more complex situation. METHODOLOGY/PRINCIPAL FINDINGS: The interpretation of sterol distribution data in a modern phylogenetic context indicates that there is a clear trend from cholesterol and other Delta(5) sterols in the earliest diverging fungal species to ergosterol in later diverging fungi. There are, however, deviations from this pattern in certain clades. Sterols of the diverse zoosporic and zygosporic forms exhibit structural diversity with cholesterol and 24-ethyl -Delta(5) sterols in zoosporic taxa, and 24-methyl sterols in zygosporic fungi. For example, each of the three monophyletic lineages of zygosporic fungi has distinctive major sterols, ergosterol in Mucorales, 22-dihydroergosterol in Dimargaritales, Harpellales, and Kickxellales (DHK clade), and 24-methyl cholesterol in Entomophthorales. Other departures from ergosterol as the dominant sterol include: 24-ethyl cholesterol in Glomeromycota, 24-ethyl cholest-7-enol and 24-ethyl-cholesta-7,24(28)-dienol in rust fungi, brassicasterol in Taphrinales and hypogeous pezizalean species, and cholesterol in Pneumocystis. CONCLUSIONS/SIGNIFICANCE: Five dominant end products of sterol biosynthesis (cholesterol, ergosterol, 24-methyl cholesterol, 24-ethyl cholesterol, brassicasterol), and intermediates in the formation of 24-ethyl cholesterol, are major sterols in 175 species of Fungi. Although most fungi in the most speciose clades have ergosterol as a major sterol, sterols are more varied than currently understood, and their distribution supports certain clades of Fungi in current fungal phylogenies. In addition to the intellectual importance of understanding evolution of sterol synthesis in fungi, there is practical importance because certain antifungal drugs (e.g., azoles) target reactions in the synthesis of ergosterol. These findings also invalidate use of ergosterol as an indicator of biomass of certain fungal taxa (e.g., Glomeromycota). Data from this study are available from the Assembling the Fungal Tree of Life (AFTOL) Structural and Biochemical Database: http://aftol.umn.edu

    Reaction pathways and textural aspects of the replacement of anhydrite by calcite at 25 °C

    Get PDF
    The replacement of sulfate minerals by calcium carbonate polymorphs (carbonation) has important implications in various geological processes occurring in Earth surface environments. In this paper we report the results of an experimental study of the interaction between anhydrite (100), (010), and (001) surfaces and Na₂CO₃ aqueous solutions under ambient conditions. Carbonation progress was monitored by glancing incidence X-ray diffraction (GIXRD) and scanning electron microscopy (SEM). We show that the reaction progresses through the dissolution of anhydrite and the simultaneous growth of calcite. The growth of calcite occurs oriented on the three anhydrite cleavage surfaces and its formation is accompanied by minor vaterite. The progress of the carbonation always occurs from the outer-ward to the inner-ward surfaces and its rate depends on the anhydrite surface considered, with the (001) surface being much more reactive than the (010) and (100) surfaces. The thickness of the formed carbonate layer grows linearly with time. The original external shape of the anhydrite crystals and their surface details (e.g., cleavage steps) are preserved during the carbonation reaction. Textural characteristics of the transformed regions, such as the gradation in the size of calcite crystals, from ~2 μm in the outer region to ~17 μm at the calcite-anhydrite interface, the local preservation of calcite crystalographic orientation with respect to anhydrite and the distribution of the microporosity mainly within the carbonate layer without development of any significant gap at the calcite-anhydrite interface. Finally, we compare these results on anhydrite carbonation with those on gypsum carbonation and can explain the differences on the basis of four parameters: (1) the molar volume change involved in the replacement process in each case, (2) the lack/existence of epitactic growth between parent and product phases, (3) the kinetics of dissolution of the different surfaces, and (4) the chemical composition (amount of structural water) of the parent phases

    Histological sub‐classification of cirrhosis using collagen proportionate area in patients with chronic hepatitis C

    Get PDF
    Collagen proportionate area (CPA, %) is used to quantify liver fibrosis. Here we assessed CPA performance to subclassify cirrhosis. CPA was measured in explanted livers from consecutively transplanted patients for hepatitis C virus‐related cirrhosis. MELD, Child‐Pugh score and decompensating events (ascites, variceal bleeding, non‐obstructive jaundice and encephalopathy) were recorded at the time of liver transplant. Of the 154 patients, 24%, 12%, 35%, 24% and 5% had 0, 1, 2, 3 and 4 previous decompensating events. Patients with decompensation had significantly higher CPA than those without (25.1±8.4 vs. 15.8±5.5, P<0.001). Decompensation was independently associated with CPA, bilirubin and albumin or with CPA and MELD score. CPA did not differ between patients with 1, 2, 3 or 4 decompensating events (22.2±6.3 vs. 26.6±8.9 vs. 24.5±7.7 vs. 24.4±10.9, P=0.242). Overall, CPA correlates with the clinical severity of cirrhosis until the advent of decompensation but not with subsequent decompensating events

    Exposure of a Tropical Soil to mg/kg of Oxytetracycline Elicits Hormetic Responses in the Catabolic Activities of its Microbial Community

    Get PDF
    Many farmers in developing countries protect their crops with oxytetracycline and fertilize their farmlands with manure from animals that received this drug as growth promoter. In this study, a tropical soil was exposed to 0.1 mg kg−1, 1 mg kg−1, and 10 mg kg−1 of oxytetracycline for 22 days to evaluate whether this antibiotic alters the capacity of a soil microbial community to metabolize 31 carbon sources. The communities exposed to 1 and 10 mg kg−1 of oxytetracycline exhibited reduced catabolic activities for 3 and 6 substrates, respectively. In contrast, the communities exposed to 0.1 mg kg−1 of oxytetracycline showed higher catabolic activities than the controls and the other two treatments for 19 substrates. These data reveal a hormetic response at the community level not previously described for soil bacteria and oxytetracycline.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET)UCR::Vicerrectoría de Docencia::Salud::Facultad de MicrobiologíaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro de Investigación en Nutrición Animal (CINA

    Daily consumption of a dairy drink enriched with DHA, Vitamins and minerals enhanced nutritional status and cognitive abilities parameters

    Get PDF
    Preadolescence is a period of growth with special nutritional requirements. In this research we investigated the effects produced by a 5-month consumption of an enriched dairy drink on biochemical and cognitive development parameters in children. Methods: 119 children (8 14y) of both genders (male 49%, female 51%) were randomly distributed into two study groups. The supplemented group (SG, n = 60) consumed 0.6 L/day (breakfast, elevenses and teatime) of an enriched dairy drink containing fish oils (high in DHA), oleic acid, carbohydrates (sugar and honey), vitamins (A, B complex, C, D, and E) and minerals (calcium, phosphorus, zinc) (Puleva Max®). The control group (CG, n = 59) consumed 0.6 L/day of standard whole milk. Both groups received the same dietary advice and consumed the dairy drinks for 5-moths, in addition to their usual diet. Blood samples and psychometric tests (some subscales of W.I.S.C.-IV of Wechsler and EVALUA of Vidal) were taken at 0 and 5 months. RM ANOVA was applied. Data are expressed as mean±SEM. Results: The consumption of the enriched dairy drink (SG) produced significant (p < 0.05) increases in plasma DHA (20%) and calcium (1.5%). Total proteins (1.9%), transferrine (2.1%), total cholesterol (3.3%) and HDLcholesterol (5.2%), but not LDL-cholesterol, decreased significantly in CG. Regarding psychometric parameters, digits span (working memory test), speed reading and reading comprehension scores showed significant increases in SG at the end of the study (16.8%, 19.1%, and 19.0% respectively) whereas CG only showed higher scores in the reading comprehension test (19.2%). Conclusion: The dietary supplementation with the enriched dairy drink improved the nutritional and biochemical status and a number of cognitive performance markers in children of 8 and 14 years. Supported by Puleva Food SA.Universidad e Granada Puleva Biotech S

    5d quivers and their AdS(6) duals

    Get PDF
    We consider an infinite class of 5d supersymmetric gauge theories involving products of symplectic and unitary groups that arise from D4-branes at orbifold singularities in Type I' string theory. The theories are argued to be dual to warped AdS(6)x S4/Zn backgrounds in massive Type IIA supergravity. In particular, this demonstrates the existence of supersymmetric 5d fixed points of quiver type. We analyze the spectrum of gauge fields and charged states in the supergravity dual, and find a precise agreement with the symmetries and charged operators in the quiver theories. We also comment on other brane objects in the supergravity dual and their interpretation in the field theories.Comment: 29 pages, 15 figure

    Terrestrial Megafauna Response to Drone Noise Levels in Ex Situ Areas

    Get PDF
    Drone use has significantly grown in recent years, and there is a knowledge gap on how the noise produced by these systems may affect animals. We investigated how 18 species of megafauna reacted to drone sound pressure levels at different frequencies. The sound pressure level on the low frequency generated by the drone did not change the studied species’ behavior, except for the Asian elephant. All other studied species showed higher noise sensitivity at medium and high frequencies. The Asian elephant was the most sensitive species to drone noise, mainly at low frequencies. Felines supported the highest sound pressure level before showing behavioral reactions. Our results suggest that drone sound pressure levels in different frequencies cause behavioral changes that differ among species, which is relevant to assessing drone disturbances in ex situ environments. The findings presented here can help to reduce drone impact for target species and serve as an experimental study for future drone use guidelines

    A practical approach with drones, smartphones, and tracking tags for potential real-time animal tracking

    Get PDF
    Drones are increasingly used for fauna monitoring and wildlife tracking; however, their application for wildlife tracking is restricted by developing such systems. Here we explore the potential of drones for wildlife tracking using an off-the-shelf system that is easy to use by non-specialists consisting of a multirotor drone, smartphones, and commercial tracking devices via Bluetooth and Ultra-Wide Band (UWB). We present the system configuration, explore the operational parameters that can affect detection capabilities, and test the effectiveness of the system for locating targets by simulating target animals in savanna and forest environments. The self-contained tracking system was built without hardware or software customization. In 40 tracking flights carried out in the Brazilian Cerrado, we obtained a detection rate of 90% in savanna and 40% in forest areas. Tests for targets in movement (N = 20), the detection rates were 90% in the savanna and 30% in the forest areas. The spatial accuracy obtained by the system was 14.61 m, being significantly more accurate in savanna (⁠x¯ = 10.53) than in forest areas (⁠x¯ = 13.06). This approach to wildlife tracking facilitates the use of drones by non-specialists at an affordable cost for conservation projects with limited resources. The reduced size of the tags, the long battery life, and the lower cost compared to GPS-tags open up a range of opportunities for animal tracking
    corecore