114 research outputs found

    Functional connectivity network between terrestrial and aquatic habitats by a generalist waterbird, and implications for biovectoring

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    Birds are vectors of dispersal of propagules of plants and other organisms including pathogens, as well as nutrients and contaminants. Thus, through their movements they create functional connectivity between habitat patches. Most studies on connectivity provided by animals to date have focused on movements within similar habitat types. However, some waterbirds regularly switch between terrestrial, coastal and freshwater habitats throughout their daily routines. Lesser black-backed gulls that overwinter in Andalusia use different habitat types for roosting and foraging. In order to reveal their potential role in biovectoring among habitats, we created an inter-habitat connectivity network based on GPS tracking data. We applied connectivity measures by considering frequently visited sites as nodes, and flights as links, to determine the strength of connections in the network between habitats, and identify functional units where connections are more likely to happen. We acquired data for 42 tagged individuals (from five breeding colonies), and identified 5676 direct flights that connected 37 nodes. These 37 sites were classified into seven habitat types: reservoirs, natural lakes, ports, coastal marshes, fish ponds, rubbish dumps and ricefields. The Donana ricefields acted as the central node in the network based on centrality measures. Furthermore, during the first half of winter when rice was harvested, ricefields were the most important habitat type in terms of total time spent. Overall, 90% of all direct flights between nodes were between rubbish dumps (for foraging) and roosts in other habitats, thereby connecting terrestrial and various wetland habitats. The strength of connections decreased between nodes as the distance between them increased, and was concentrated within ten independent spatial and functional units, especially between December and February. The pivotal role for ricefields and rubbish dumps in the network, and their high connectivity with aquatic habitats in general, have important implications for biovectoring into their surroundings. (C) 2019 The Authors. Published by Elsevier B.V

    Interstellar reddening towards six small areas in Puppis-Vela

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    We investigate the distribution of the interstellar dust towards six small volumes of the sky in the region of the Gum nebula. New high-quality four-colour uvby and H\beta\ Str\"omgren photometry obtained for 352 stars in six selected areas of Kapteyn, complemented with data obtained in a previous investigation for two of these areas, were used to estimate the colour excess and distance to these objects. The obtained colour excess versus distance diagrams, complemented with other information, when available, were analysed in order to infer the properties of the interstellar medium permeating the observed volumes. On the basis of the overall standard deviation in the photometric measurements, we estimate that colour excesses and distances are determined with an accuracy of 0.010 mag and better than 30%, respectively, for a sample of 520 stars. A comparison with 37 stars in common with the new Hipparcos catalogue attests to the high quality of the photometric distance determination. The obtained colour excess versus distance diagrams testify to the low density volume towards the observed lines-of-sight. Very few stars out to distances of 1 kpc from the Sun have colour excesses larger than E(b-y) = 0.1 mag. In spite of the low density character of the interstellar medium towards the Puppis-Vela direction, the obtained reddening as a function of the distance indicates that two or more interstellar structures are crossed towards the observed lines-of-sight. One of these structures may be associated with the very low density wall of the Local Cavity, which has a distance of 100-150 pc from the Sun. Another structure might be related to the Gum nebula, and if so, its front face would be located at about 350 pc from the Sun.Comment: Accepted by Astronomy and Astrophysic

    Search for broad absorption lines in spectra of stars in the field of supernova remnant RX J0852.0-4622 (Vela Jr.)

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    Supernova remnant (SNR) RX J0852.0-4622 is one of the youngest and is most likely the closest among known galactic supernova remnants (SNRs). It was detected in X-rays, the 44Ti gamma-line, and radio. We obtain and analyze medium-resolution spectra of 14 stars in the direction towards the SNR RX J0852.0-4622 in an attempt to detect broad absorption lines of unshocked ejecta against background stars. Spectral synthesis is performed for all the stars in the wavelength range of 3740-4020AA to extract the broad absorption lines of Ca II related to the SNR RX J0852.0-4622. We do not detect any broad absorption line and place a 3-sigma upper limit on the relative depths of <0.04 for the broad Ca II absorption produced by the SNR. We detect narrow low and high velocity absorption components of Ca II. High velocity |V(LSR)|=100-140 km/s components are attributed to radiative shocks in clouds engulfed by the old Vela SNR. The upper limit to the absorption line strength combined with the width and flux of the 44Ti gamma-ray line 1.16 MeV lead us to conclude that SNR RX J0852.0-4622 was probably produced by an energetic SN Ic explosion.Comment: 9 pages, 8 figures, accepted in A&

    The Mechanism of (R,R) ZX-5 on Increasing NO Release

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    (R,R) ZX-5 has been proven to have positive effects on choroidal blood flow without affecting the sclera and ciliary bodies in New Zealand white rabbits. This study was designed to investigate the mechanisms of (R,R) ZX-5 on improving the choroidal blood flow and promoting NO production. HUVECs (human umbilical vein endothelial cells) were used to determine the production of eNOS, p-eNOS, AKT and Erk1/2 by Western blot analysis. iNOS and eNOS mRNA levels were investigated by RT-PCR and the effect of (R,R) ZX-5 on NO production were determined by eNOS activity assay. We found (R,R) ZX-5 upregulated protein expression of eNOS and iNOS, increased NO production, and reduced ERK and Akt protein level. Therefore, (R,R) ZX-5 may promote the choroidal blood flow in New Zealand white rabbits without affecting the blood flow in the iris or ciliary bodies via increasing NO production. These results suggest that (R,R) ZX-5 may function to cure and prevent Age-related macular degeneration (AMD)

    Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

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    Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≄1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≀6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
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