216 research outputs found

    Invasive alien species as reservoirs for pathogens

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    Alien plant and animal hosts play an important role as vectors of dangerous pathogens. However, the knowledge on pathogens of many host species is still limited. To bridge this gap, we collated information on pathogens carried by 118 alien species in Europe in their native and secondary range. In Europe, these species are considered as invasive. Using the dataset we determined most prevailing pathogen groups and plant and animal hosts that carried the highest number of pathogens. The most numerous pathogens were bacteria Xylella fastidiosa (plants) and Rabies virus (animals). The principal pathogen groups among plant hosts were Arthropoda (phylum), Insecta (class) and Hemiptera (order), and among animal hosts – Platyhelminthes (phylum), Trematoda (class) and Plagiorchiida/Strongylida (order). In plants, the highest number of pathogens was recorded for Ambrosia artemisiifolia; in animals, Procyon lotor was the most infested species. Hosts introduced from North America carried the highest numbers of pathogen species; in addition, unintentionally introduced hosts carried more pathogens than those introduced intentionally. We revealed also that the level of infestation differs between the habitats in which the hosts occur. It should be also stressed that in all analyses the number of pathogens increased with the number of publications on the particular host’ infestation. The highest number of publications was available for species useful for human, such as Crassostrea gigas. The results demonstrated that there are still significant gaps in the knowledge on the role of other hosts, including invasive ones (e.g., Sciurus niger) in pathogen transmission

    Physicochemical and Biological Characterisation of Diclofenac Oligomeric Poly(3-hydroxyoctanoate) Hybrids as ÎČ-TCP Ceramics Modifiers for Bone Tissue Regeneration

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    Nowadays, regenerative medicine faces a major challenge in providing new, functional materials that will meet the characteristics desired to replenish and grow new tissue. Therefore, this study presents new ceramic-polymer composites in which the matrix consists of tricalcium phosphates covered with blends containing a chemically bounded diclofenac with the biocompatible polymer-poly(3-hydroxyoctanoate), P(3HO). Modification of P(3HO) oligomers was confirmed by NMR, IR and XPS. Moreover, obtained oligomers and their blends were subjected to an in-depth characterisation using GPC, TGA, DSC and AFM. Furthermore, we demonstrate that the hydrophobicity and surface free energy values of blends decreased with the amount of diclofenac modified oligomers. Subsequently, the designed composites were used as a substrate for growth of the pre-osteoblast cell line (MC3T3-E1). An in vitro biocompatibility study showed that the composite with the lowest concentration of the proposed drug is within the range assumed to be non-toxic (viability above 70%). Cell proliferation was visualised using the SEM method, whereas the observation of cell penetration into the scaffold was carried out by confocal microscopy. Thus, it can be an ideal new functional bone tissue substitute, allowing not only the regeneration and restoration of the defect but also inhibiting the development of chronic inflammation

    Clustering of the AKARI NEP deep field 24<i>Ό</i>m selected galaxies

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    Aims. We present a method of selection of 24 ÎŒm galaxies from the AKARI north ecliptic pole (NEP) deep field down to 150 ÎŒJy and measurements of their two-point correlation function. We aim to associate various 24 ÎŒm selected galaxy populations with present day galaxies and to investigate the impact of their environment on the direction of their subsequent evolution. Methods. We discuss using of Support Vector Machines (SVM) algorithm applied to infrared photometric data to perform star-galaxy separation, in which we achieve an accuracy higher than 80%. The photometric redshift information, obtained through the CIGALE code, is used to explore the redshift dependence of the correlation function parameter (r0) as well as the linear bias evolution. This parameter relates galaxy distribution to the one of the underlying dark matter. We connect the investigated sources to their potential local descendants through a simplified model of the clustering evolution without interactions. Results. We observe two different populations of star-forming galaxies, at zmed ∌ 0.25, zmed ∌ 0.9. Measurements of total infrared luminosities (LTIR) show that the sample at zmed ∌ 0.25 is composed mostly of local star-forming galaxies, while the sample at zmed ∌ 0.9 is composed of luminous infrared galaxies (LIRGs) with LTIR ∌ 1011.62 L⹀. We find that dark halo mass is not necessarily correlated with the LTIR: for subsamples with LTIR = 1011.15 L⹀ at zmed ∌ 0.7 we observe a higher clustering length (r0 = 6.21 ± 0.78 [h−1Mpc]) than for a subsample with mean LTIR = 1011.84 L⹀ at zmed ∌ 1.1 (r0 = 5.86 ± 0.69 h−1Mpc). We find that galaxies at zmed ∌ 0.9 can be ancestors of present day L∗ early type galaxies, which exhibit a very high r0 ∌ 8h−1 Mpc.</p

    VIPERS: An Unprecedented View of Galaxies and Large-Scale Structure Halfway Back in the Life of the Universe

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    The VIMOS Public Extragalactic Redshift Survey (VIPERS) is an ongoing ESO Large Programme to map in detail the large-scale distribution of galaxies at 0.5 < z <1.2. With a combination of volume and sampling density that is unique for these redshifts, it focuses on measuring galaxy clustering and related cosmological quantities as part of the grand challenge of understanding the origin of cosmic acceleration. VIPERS has also been designed to guarantee a broader legacy, allowing detailed investigations of the properties and evolutionary trends of z~1 galaxies. The survey strategy exploits the specific advantages of the VIMOS spectrograph at the VLT, aiming at a final sample of nearly 100,000 galaxy redshifts to iAB = 22.5 mag, which represents the largest redshift survey ever performed with ESO telescopes. In this introductory article we describe the survey construction, together with early results based on a first sample of ~55,000 galaxies.Comment: 6 pages, 8 figures; introductory pape

    Posture as Index for Approach-Avoidance Behavior

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    Approach and avoidance are two behavioral responses that make people tend to approach positive and avoid negative situations. This study examines whether postural behavior is influenced by the affective state of pictures. While standing on the Wiiℱ Balance Board, participants viewed pleasant, neutral, and unpleasant pictures (passively viewing phase). Then they had to move their body to the left or the right (lateral movement phase) to make the next picture appear. We recorded movements in the anterior-posterior direction to examine approach and avoidant behavior. During passively viewing, people approached pleasant pictures. They avoided unpleasant ones while they made a lateral movement. These findings provide support for the idea that we tend to approach positive and avoid negative situations

    Limits on diffuse fluxes of high energy extraterrestrial neutrinos with the AMANDA-B10 detector

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    Data from the AMANDA-B10 detector taken during the austral winter of 1997 have been searched for a diffuse flux of high energy extraterrestrial muon-neutrinos, as predicted from, e.g., the sum of all active galaxies in the universe. This search yielded no excess events above those expected from the background atmospheric neutrinos, leading to upper limits on the extraterrestrial neutrino flux. For an assumed E^-2 spectrum, a 90% classical confidence level upper limit has been placed at a level E^2 Phi(E) = 8.4 x 10^-7 GeV cm^-2 s^-1 sr^-1 (for a predominant neutrino energy range 6-1000 TeV) which is the most restrictive bound placed by any neutrino detector. When specific predicted spectral forms are considered, it is found that some are excluded.Comment: Submitted to Physical Review Letter

    The AMANDA Neutrino Telescope and the Indirect Search for Dark Matter

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    With an effective telescope area of order 10^4 m^2, a threshold of ~50 GeV and a pointing accuracy of 2.5 degrees, the AMANDA detector represents the first of a new generation of high energy neutrino telescopes, reaching a scale envisaged over 25 years ago. We describe its performance, focussing on the capability to detect halo dark matter particles via their annihilation into neutrinos.Comment: Latex2.09, 16 pages, uses epsf.sty to place 15 postscript figures. Talk presented at the 3rd International Symposium on Sources and Detection of Dark Matter in the Universe (DM98), Santa Monica, California, Feb. 199

    Search for Point Sources of High Energy Neutrinos with AMANDA

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    This paper describes the search for astronomical sources of high-energy neutrinos using the AMANDA-B10 detector, an array of 302 photomultiplier tubes, used for the detection of Cherenkov light from upward traveling neutrino-induced muons, buried deep in ice at the South Pole. The absolute pointing accuracy and angular resolution were studied by using coincident events between the AMANDA detector and two independent telescopes on the surface, the GASP air Cherenkov telescope and the SPASE extensive air shower array. Using data collected from April to October of 1997 (130.1 days of livetime), a general survey of the northern hemisphere revealed no statistically significant excess of events from any direction. The sensitivity for a flux of muon neutrinos is based on the effective detection area for through-going muons. Averaged over the Northern sky, the effective detection area exceeds 10,000 m^2 for E_{mu} ~ 10 TeV. Neutrinos generated in the atmosphere by cosmic ray interactions were used to verify the predicted performance of the detector. For a source with a differential energy spectrum proportional to E_{nu}^{-2} and declination larger than +40 degrees, we obtain E^2(dN_{nu}/dE) <= 10^{-6}GeVcm^{-2}s^{-1} for an energy threshold of 10 GeV.Comment: 46 pages, 22 figures, 4 tables, submitted to Ap.

    Muon Track Reconstruction and Data Selection Techniques in AMANDA

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    The Antarctic Muon And Neutrino Detector Array (AMANDA) is a high-energy neutrino telescope operating at the geographic South Pole. It is a lattice of photo-multiplier tubes buried deep in the polar ice between 1500m and 2000m. The primary goal of this detector is to discover astrophysical sources of high energy neutrinos. A high-energy muon neutrino coming through the earth from the Northern Hemisphere can be identified by the secondary muon moving upward through the detector. The muon tracks are reconstructed with a maximum likelihood method. It models the arrival times and amplitudes of Cherenkov photons registered by the photo-multipliers. This paper describes the different methods of reconstruction, which have been successfully implemented within AMANDA. Strategies for optimizing the reconstruction performance and rejecting background are presented. For a typical analysis procedure the direction of tracks are reconstructed with about 2 degree accuracy.Comment: 40 pages, 16 Postscript figures, uses elsart.st
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