429 research outputs found

    Impacts on freshwater macrophytes produced by small invertebrate herbivores:Afrotropical and Neotropical wetlands compared

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    We compare invertebrate herbivory upon 13 macrophyte species in freshwater wetland systems located in two global ecozones, the Afrotropics and Neotropics, in the context of biotic and environmental factors influencing these wetlands. The two ecozones are climatically similar regions, with similar water chemistry, but experience contrasting grazing and disturbance pressures from large mammalian herbivores. Our results for macrophytes show that small invertebrates removed significantly more lamina biomass per leaf in Neotropical macrophytes (6.55%) than Afrotropical ones (4.99%). Overall, the results indicate that underestimation of up to 15.6% of leaf biomass may occur if plant tissue removal by invertebrate herbivores is not included in estimates of plant biomass. Regarding the contrasting grazing and disturbance pressures from large herbivores influencing these wetlands, seven mammal species (especially the Black Lechwe antelope, Kobus leche) were observed impacting macrophytes in the Afrotropical wetlands, while in the Neotropics, only much smaller rodents, capybara, (Hydrochoerus hydrochaeris) were sporadically observed. We discuss the relevance of results for invertebrate herbivory in the context of both the methodological approach and the importance of large mammalian herbivores as biotic factors additionally impacting macrophyte populations in these subtropical to tropical wetlands.Fil: Franceschini, Maria Celeste. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Centro de EcologĂ­a Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de EcologĂ­a Aplicada del Litoral; ArgentinaFil: Murphy, Kevin. University of Glasgow; Reino UnidoFil: Moore, Isabel. University of Glasgow; Reino UnidoFil: Kennedy, Michael P.. University of Aberdeen; Reino UnidoFil: MartĂ­nez, Fedra Solange. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Centro de EcologĂ­a Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de EcologĂ­a Aplicada del Litoral; ArgentinaFil: Willems, Frank. Kasanka Trust - Kasanka National Park; ZambiaFil: de Wysiecki, Maria Laura. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Centro de Estudios ParasitolĂłgicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios ParasitolĂłgicos y de Vectores; ArgentinaFil: Sichingabula, Henry. University Of Zambia; Zambi

    Changes in surface water drive the movements of Shoebills

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    Animal movement is mainly determined by spatial and temporal changes in resource availability. For wetland specialists, the seasonal availability of surface water may be a major determinant of their movement patterns. This study is the first to examine the movements of Shoebills (Balaeniceps rex), an iconic and vulnerable bird species. Using GPS transmitters deployed on six immature and one adult Shoebills over a 5-year period, during which four immatures matured into adults, we analyse their home ranges and distances moved in the Bangweulu Wetlands, Zambia. We relate their movements at the start of the rainy season (October to December) to changes in Normalized Difference Water Index (NDWI), a proxy for surface water. We show that Shoebills stay in the Bangweulu Wetlands all year round, moving less than 3 km per day on 81% of days. However, average annual home ranges were large, with high individual variability, but were similar between age classes. Immature and adult Shoebills responded differently to changes in surface water; sites that adults abandoned became drier, while sites abandoned by immatures became wetter. However, there were no differences in NDWI of areas used by Shoebills before abandonment and newly selected sites, suggesting that Shoebills select areas with similar surface water. We hypothesise that the different responses to changes in surface water by immature and adult Shoebills are related to age-specific optimal foraging conditions and fishing techniques. Our study highlights the need to understand the movements of Shoebills throughout their life cycle to design successful conservation actions for this emblematic, yet poorly known, species

    Effects of early intracoronary streptokinase on infarct size estimated from cumulative enzyme release and on enzyme release rate: A randomized trial of 533 patients with acute myocardial infarction

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    The effects of early intracoronary streptokinase (SK) on enzymatic infarct size and rate of enzyme release were studied in a randomized multicenter trial. A total of 533 patients with acute myocardial infarction (AMI) were allocated to either the SK treatment group (n = 269) or the conventional (control) treatment group (n = 264). Enzymatic infarct size was represented by the cumulative quantity of alpha-hydroxybutyrate dehydrogenase (HBDH) released by the heart per liter of plasma in the first 72 hours. Rate of enzyme release was represented by the ratio of HBDH quantities released in 24 hours and 72 hours. On an "intention to treat" basis, the SK group had a smaller (by 30%; p = 0.0001) median enzymatic infarct size and a higher (by 35%; p = 0.0001) median rate of enzyme release than the control group. Limitation of infarct size was less apparent in patients tre

    Assessing the prognostic value of tumor-infiltrating CD57+ cells in advanced stage head and neck cancer using QuPath digital image analysis

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    This study aimed to assess the prognostic value of intratumoral CD57+ cells in head and neck squamous cell carcinoma (HNSCC) and to examine the reproducibility of these analyses using QuPath. Pretreatment biopsies of 159 patients with HPV-negative, stage III/IV HNSCC treated with chemoradiotherapy were immunohistochemically stained for CD57. The number of CD57+ cells per mm2 tumor epithelium was quantified by two independent observers and by QuPath, software for digital pathology image analysis. Concordance between the observers and QuPath was assessed by intraclass correlation coefficients (ICC). The correlation between CD57 and clinicopathological characteristics was assessed; associations with clinical outcome were estimated using Cox proportional hazard analysis and visualized using Kaplan-Meier curves. The patient cohort had a 3-year OS of 65.8% with a median follow-up of 54 months. The number of CD57+ cells/mm2 tumor tissue did not correlate to OS, DFS, or LRC. N stage predicted prognosis (OS: HR 0.43, p = 0.008; DFS: HR 0.41, p = 0.003; LRC: HR 0.24, p = 0.007), as did WHO performance state (OS: HR 0.48, p = 0.028; LRC: 0.33, p = 0.039). Quantification by QuPath showed moderate to good concordance with two human observers (ICCs 0.836, CI 0.805–0.863, and 0.741, CI 0.692–0.783, respectively). In conclusion, the presence of CD57+ TILs did not correlate to prognosis in advanced stage, HPV-negative HNSCC patients treated with chemoradiotherapy. Substantial concordance between human observers and QuPath was found, confirming a promising future role for digital, algorithm driven image analysis

    MAXI J1659-152: The shortest orbital period black-hole transient in outburst

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    MAXI J1659-152 is a bright X-ray transient black-hole candidate binary system discovered in September 2010. We report here on MAXI, RXTE, Swift, and XMM-Newton observations during its 2010/2011 outburst. We find that during the first one and a half week of the outburst the X-ray light curves display drops in intensity at regular intervals, which we interpret as absorption dips. About three weeks into the outbursts, again drops in intensity are seen. These dips have, however, a spectral behaviour opposite to that of the absorption dips, and are related to fast spectral state changes (hence referred to as transition dips). The absorption dips recur with a period of 2.414+/-0.005 hrs, which we interpret as the orbital period of the system. This implies that MAXI J1659-152 is the shortest period black-hole candidate binary known to date. The inclination of the accretion disk with respect to the line of sight is estimated to be 65-80 degrees. We propose the companion to the black-hole candidate to be close to an M5 dwarf star, with a mass and radius of about 0.15-0.25 M_sun and 0.2-0.25 R_sun, respectively. We derive that the companion had an initial mass of about 1.5 M_sun, which evolved to its current mass in about 5-6 billion years. The system is rather compact (orbital separation of larger than ~1.33 R_sun), and is located at a distance of 8.6+/-3.7 kpc, with a height above the Galactic plane of 2.4+/-1.0 kpc. The characteristics of short orbital period and high Galactic scale height are shared with two other transient black-hole candidate X-ray binaries, i.e., XTE J1118+480 and Swift J1735.5-0127. We suggest that all three are kicked out of the Galactic plane into the halo, rather than being formed in a globular cluster.Comment: 20 pages, 14 figures, accepted for publication in A&

    Searching for a Stochastic Background of Gravitational Waves with LIGO

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    The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is ΩGW<6.5×10−5\Omega_{\rm GW} < 6.5 \times 10^{-5}. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

    Quantum state preparation and macroscopic entanglement in gravitational-wave detectors

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    Long-baseline laser-interferometer gravitational-wave detectors are operating at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within a broad frequency band. Such a low classical noise budget has already allowed the creation of a controlled 2.7 kg macroscopic oscillator with an effective eigenfrequency of 150 Hz and an occupation number of 200. This result, along with the prospect for further improvements, heralds the new possibility of experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical behavior of objects in the realm of everyday experience - using gravitational-wave detectors. In this paper, we provide the mathematical foundation for the first step of a MQM experiment: the preparation of a macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum state, which is possible if the interferometer's classical noise beats the SQL in a broad frequency band. Our formalism, based on Wiener filtering, allows a straightforward conversion from the classical noise budget of a laser interferometer, in terms of noise spectra, into the strategy for quantum state preparation, and the quality of the prepared state. Using this formalism, we consider how Gaussian entanglement can be built among two macroscopic test masses, and the performance of the planned Advanced LIGO interferometers in quantum-state preparation

    Prehospital ticagrelor in ST-segment elevation myocardial infarction

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    Background:The direct-acting platelet P2Y receptor antagonist ticagrelor can reduce the incidence of major adverse cardiovascular events when administered at hospital admission to patients with ST-segment elevation myocardial infarction (STEMI). Whether prehospital administration of ticagrelor can improve coronary reperfusion and the clinical outcome is unknown. Methods: We conducted an international, multicenter, randomized, double-blind study involving 1862 patients with ongoing STEMI of less than 6 hours' duration, comparing prehospital (in the ambulance) versus in-hospital (in the catheterization laboratory) treatment with ticagrelor. The coprimary end points were the proportion of patients who did not have a 70% or greater resolution of ST-segment elevation before percutaneous coronary intervention (PCI) and the proportion of patients who did not have Thrombolysis in Myocardial Infarction flow grade 3 in the infarct-related artery at initial angiography. Secondary end points included the rates of major adverse cardiovascular events and definite stent thrombosis at 30 days. Results: The median time from randomization to angiography was 48 minutes, and the median time difference between the two treatment strategies was 31 minutes. The two coprimary end points did not differ significantly between the prehospital and in-hospital groups. The absence of ST-segment elevation resolution of 70% or greater after PCI (a secondary end point) was reported for 42.5% and 47.5% of the patients, respectively. The rates of major adverse cardiovascular events did not differ significantly between the two study groups. The rates of definite stent thrombosis were lower in the prehospital group than in the in-hospital group (0% vs. 0.8% in the first 24 hours; 0.2% vs. 1.2% at 30 days). Rates of major bleeding events were low and virtually identical in the two groups, regardless of the bleeding definition use

    Rubrivivax benzoatilyticus sp.nov., an aromatic hydrocarbon-degrading purple betaproteobacterium

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    A brown-coloured bacterium was isolated from photoheterotrophic (benzoate) enrichments of flooded paddy soil from Andhra Pradesh, India. On the basis of 16S rRNA gene sequence analysis, strain JA2(T) was shown to belong to the class Betaproteobacteria, related to Rubrivivax gelatinosus (99 % sequence similarity). Cells of strain JA2(T) are Gram-negative, motile rods with monopolar single flagella. The strain contained bacteriochlorophyll a and most probably the carotenoids spirilloxanthin and sphaeroidene, but did not have internal membrane structures. Intact cells had absorption maxima at 378, 488, 520, 590, 802 and 884 nm. No growth factors were required. Strain JA2(T) grew on benzoate, 2-aminobenzoate (anthranilate), 4-aminobenzoate, 4-hydroxybenzoate, phthalate, phenylalanine, trans-cinnamate, benzamide, salicylate, cyclohexanone, cyclohexanol and cyclohexane-2-carboxylate as carbon sources and/or electron donors. The DNA G+C content was 74.9 mol%. Based on DNA-DNA hybridization studies, 16S rRNA gene sequence analysis and morphological and physiological characteristics, strain JA2(T) is different from representatives of other photosynthetic species of the Betaproteobacteria and was recognised as representing a novel species, for which the name Rubrivivax benzoatilyticus sp. nov. is proposed. The type strain is JA2(T) (=ATCC BAA-35(T)=JCM 13220(T)=MTCC 7087(T))
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