461 research outputs found

    The dynamics of the population and peculiarities of the morphometric structure of Melophagus ovinus (Diptera, Hippoboscidae) in Ukraine

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    The indices of the Melophagus ovinus (Linnaeus, 1758) population in Ukraine, and also the peculiarities of morphological and metric structure of the insects’ body at all the stages of their development within the conditions of the surveyed region were investigated. New data on morphometric differential signs of sexually mature males and females of sheep bloodsuckers were obtained. We established that M. ovinus is significantly widespread in Poltava and Zaporizhzhia regions, and parasitizes 26.1% of the examined sheep stock with the infection intensity of 92.7 ± 1.4 specimens and abundance – 24.7 specimens on one animal. The dynamics of M. ovinus population at different stages of development was characterized by the highest abundance of sexually mature males (11.1 specimens on one animal) and females (8.9 specimens). The given index concerning pupae and larvae was considerably lower (4.2 and 0.5 specimens on one animal). It was found that post-embryonic and adult development stages of M. ovinus differ in their metric indices.The length and width of the pupae were 17.4% and 13.2% larger than those of the larvae. The sizes of males and females relative to the indices of body length, the length and width of head, thoracic, and abdominal segments, the length of maxillary palpus and the length and width of the proboscis in fact differ in their values. The differential morphological species signs of M. ovinus are the form and location of the oculi, antennae, the structure of the head segment of the body, and the mouthparts, and of sexual dimorphism – the distance from the caudal segment of the copulatory apparatus to the rear of the insect’s last abdominal segment. The indices of the Melophagus ovinus (Linnaeus, 1758) population in Ukraine, and also the peculiarities of morphological and metric structure of the insects’ body at all the stages of their development within the conditions of the surveyed region were investigated. New data on morphometric differential signs of sexually mature males and females of sheep bloodsuckers were obtained. It was established that M. ovinus are significantly widespread in Poltava and Zaporizhzhia regions, and they parasitize 26.1% of the examined sheep stock with the infection intensity of 92.7 ± 1.4 specimens and abundance – 24.7 specimens on one animal. The dynamics of M. ovinus population at different stages of development was characterized by the highest abundance of sexually mature males (11.1 specimens) and females (8.9 specimens). The given index concerning pupae and larvae was considerably lower (4.2 and 0.5 specimens on one animal). It was found that post-embryonic and adult development stages of M. ovinus differ in their metric indices.The length and width of the pupae were 17.4% and 13.2% larger than those of the larvae. The sizes of males and females relative to the indices of body length, the length and width of head, thoracic, and abdominal segments, the length of maxillary palpus and the length and width of the proboscis in fact differ in their values. The differential morphological species signs of M. ovinus are the form and location of oculi, antennae, the structure of the head segment of the body, and the mouthparts, and of sexual dimorphism – the distance from the caudal segment of the copulatory apparatus to the rear of the insect’s last abdominal segment.

    Highlights from the Pierre Auger Observatory

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    The Pierre Auger Observatory is the world's largest cosmic ray observatory. Our current exposure reaches nearly 40,000 km2^2 str and provides us with an unprecedented quality data set. The performance and stability of the detectors and their enhancements are described. Data analyses have led to a number of major breakthroughs. Among these we discuss the energy spectrum and the searches for large-scale anisotropies. We present analyses of our Xmax_{max} data and show how it can be interpreted in terms of mass composition. We also describe some new analyses that extract mass sensitive parameters from the 100% duty cycle SD data. A coherent interpretation of all these recent results opens new directions. The consequences regarding the cosmic ray composition and the properties of UHECR sources are briefly discussed.Comment: 9 pages, 12 figures, talk given at the 33rd International Cosmic Ray Conference, Rio de Janeiro 201

    The Pierre Auger Observatory III: Other Astrophysical Observations

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    Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger ObservatoryComment: Contributions to the 32nd International Cosmic Ray Conference, Beijing, China, August 201

    A search for point sources of EeV photons

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    Measurements of air showers made using the hybrid technique developed with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for point sources of EeV photons anywhere in the exposed sky. A multivariate analysis reduces the background of hadronic cosmic rays. The search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been detected. An upper limit on the photon flux has been derived for every direction. The mean value of the energy flux limit that results from this, assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in which EeV cosmic ray protons are emitted by non-transient sources in the Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical Journa

    Reconstruction of inclined air showers detected with the Pierre Auger Observatory

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    We describe the method devised to reconstruct inclined cosmic-ray air showers with zenith angles greater than 60∘60^\circ detected with the surface array of the Pierre Auger Observatory. The measured signals at the ground level are fitted to muon density distributions predicted with atmospheric cascade models to obtain the relative shower size as an overall normalization parameter. The method is evaluated using simulated showers to test its performance. The energy of the cosmic rays is calibrated using a sub-sample of events reconstructed with both the fluorescence and surface array techniques. The reconstruction method described here provides the basis of complementary analyses including an independent measurement of the energy spectrum of ultra-high energy cosmic rays using very inclined events collected by the Pierre Auger Observatory.Comment: 27 pages, 19 figures, accepted for publication in Journal of Cosmology and Astroparticle Physics (JCAP

    Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

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    We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.Comment: Accepted for publication by PR

    WEST NILE FEVER WORLDWIDE AND IN THE TERRITORY OF THE RUSSIAN FEDERATION IN 2016, AND FORECAST OF EPIDEMIC SITUATION DEVELOPMENT IN 2017

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    In Europe, as in Russia and Canada, outlined was a tendency to the increase in the morbidity rates, while in the US – the incidence was somewhat lower as compared to previous years. On the whole, West Nile fever incidence rates in the Russian Federation by regions during the epidemic season, 2016 were below the average long-term index. Above the average regional annual incidence rates were registered in the Saratov region only and accounted for 64 % of all reported cases in Russia. Analysis of the monitoring results indicated the circulation of WNF virus markers in carriers of the pathogen in 10 constituent entities of the Russian Federation, and the presence of IgG antibodies in healthy population cohorts in 30 RF entities. According to molecular-genetic typing of WNF virus samples from a deceased patient in the Astrakhan Region and mosquito Culex samples from the Volgograd Region, WNF virus genotype I was established. Forecasting of epidemiological situation development for the year 2017 does not rule out the possibility of local increase in WNF incidence in certain regions of Russia

    Operations of and Future Plans for the Pierre Auger Observatory

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    Technical reports on operations and features of the Pierre Auger Observatory, including ongoing and planned enhancements and the status of the future northern hemisphere portion of the Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200

    Azimuthal asymmetry in the risetime of the surface detector signals of the Pierre Auger Observatory

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    The azimuthal asymmetry in the risetime of signals in Auger surface detector stations is a source of information on shower development. The azimuthal asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable, (sec⁡ξ)max(\sec \theta)_\mathrm{max}, sensitive to the mass composition of cosmic rays above 3×10183 \times 10^{18} eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJETII-04 and EPOS-LHC) an indication that the mean cosmic-ray mass increases slowly with energy, as has been inferred from other studies. However, the mass estimates are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modelling that must be resolved before the mass composition can be inferred from (sec⁡ξ)max(\sec \theta)_\mathrm{max}.Comment: Replaced with published version. Added journal reference and DO
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