ABSTRACT The events recorded by ARGO-YBJ in more than five years of data collection have been analyzed to determine the diffuse gamma-ray emission in the Galactic plane at Galactic longitudes 25° < l ...< 100° and Galactic latitudes . The energy range covered by this analysis, from ∼350 GeV to ∼2 TeV, allows the connection of the region explored by Fermi with the multi-TeV measurements carried out by Milagro. Our analysis has been focused on two selected regions of the Galactic plane, i.e., 40° < l < 100° and 65° < l < 85° (the Cygnus region), where Milagro observed an excess with respect to the predictions of current models. Great care has been taken in order to mask the most intense gamma-ray sources, including the TeV counterpart of the Cygnus cocoon recently identified by ARGO-YBJ, and to remove residual contributions. The ARGO-YBJ results do not show any excess at sub-TeV energies corresponding to the excess found by Milagro, and are consistent with the predictions of the Fermi model for the diffuse Galactic emission. From the measured energy distribution we derive spectral indices and the differential flux at 1 TeV of the diffuse gamma-ray emission in the sky regions investigated.
The extended TeV gamma-ray source ARGO J2031+4157 (or MGRO J2031+41) is positionally consistent with the Cygnus Cocoon discovered by Fermi-LAT at GeV energies in the Cygnus superbubble. Reanalyzing ...the ARGO-YBJ data collected from 2007 November to 2013 January, the angular extension and energy spectrum of ARGO J2031+4157 are evaluated. After subtracting the contribution of the overlapping TeV sources, the ARGO-YBJ excess map is fitted with a two-dimensional Gaussian function in a square region of 10degrees x 10degrees, finding a source extension sigma sub(ext)= 1degrees.8 + or - 0degrees.5. The observed differential energy spectrum is dN/dE = (2.5 + or - 0.4) x 10 super(-11) (E/1 TeV) super(-2.6+ or -0.3) photons cm super(-2) s super(-1) TeV super(-1), in the energy range 0.2-10 TeV. The angular extension is consistent with that of the Cygnus Cocoon as measured by Fermi-LAT and the spectrum also shows a good connection with the one measured in the 1-100 GeV energy range. These features suggest to identify ARGO J2031+4157 as the counterpart of the Cygnus Cocoon at TeV energies. The Cygnus Cocoon, located in the star-forming region of Cygnus X, is interpreted as a cocoon of freshly accelerated cosmic rays related to the Cygnus superbubble. The spectral similarity with supernova remnants (SNRs) indicates that the particle acceleration inside a superbubble is similar to that in an SNR. The spectral measurements from 1 GeV to 10 TeV allows for the first time to determine the possible spectrum slope of the underlying particle distribution. A hadronic model is adopted to explain the spectral energy distribution.
ABSTRACT This paper reports on the measurement of the large-scale anisotropy in the distribution of cosmic-ray arrival directions using the data collected by the air shower detector ARGO-YBJ from ...2008 January to 2009 December, during the minimum of solar activity between cycles 23 and 24. In this period, more than 2 × 1011 showers were recorded with energies between ∼1 and 30 TeV. The observed two-dimensional distribution of cosmic rays is characterized by two wide regions of excess and deficit, respectively, both of relative intensity ∼10−3 with respect to a uniform flux, superimposed on smaller size structures. The harmonic analysis shows that the large-scale cosmic-ray relative intensity as a function of R.A. can be described by the first and second terms of a Fouries series. The high event statistics allow the study of the energy dependence of the anistropy, showing that the amplitude increases with energy, with a maximum intensity at ∼10 TeV, and then decreases while the phase slowly shifts toward lower values of R.A. with increasing energy. The ARGO-YBJ data provide accurate observations over more than a decade of energy around this feature of the anisotropy spectrum.
ABSTRACT We report on the extensive multi-wavelength observations of the blazar Markarian 421 (Mrk 421) covering radio to γ-rays, during the 4.5 year period of ARGO-YBJ and Fermi common operation ...time, from 2008 August to 2013 February. These long-term observations, extending over an energy range of 18 orders of magnitude, provide a unique chance to study the variable emission of Mrk 421. In particular, due to the ARGO-YBJ and Fermi data, the entire energy range from 100 MeV to 10 TeV is covered without any gap. In the observation period, Mrk 421 showed both low- and high-activity states at all wavebands. The correlations among flux variations in different wavebands were analyzed. The X-ray flux is clearly correlated with the TeV γ-ray flux, while the GeV γ-rays only show a partial correlation with the TeV γ-rays. Radio and UV fluxes seem to be weakly or not correlated with the X-ray and γ-ray fluxes. Seven large flares, including five X-ray flares and two GeV γ-ray flares with variable durations (3-58 days), and one X-ray outburst phase were identified and used to investigate the variation of the spectral energy distribution with respect to a relative quiescent phase. During the outburst phase and the seven flaring episodes, the peak energy in X-rays is observed to increase from sub-keV to a few keV. The TeV γ-ray flux increases up to 0.9-7.2 times the flux of the Crab Nebula. The behavior of GeV γ-rays is found to vary depending on the flare, a feature that leads us to classify flares into three groups according to the GeV flux variation. Finally, the one-zone synchrotron self-Compton model was adopted to describe the emission spectra. Two out of three groups can be satisfactorily described using injected electrons with a power-law spectral index around 2.2, as expected from relativistic diffuse shock acceleration, whereas the remaining group requires a harder injected spectrum. The underlying physical mechanisms responsible for different groups may be related to the acceleration process or to the environment properties.
The Astrophysical Radiation with Ground-based Observatory at Yang Ba Jing (ARGO-YBJ) detector is an extensive air shower array that has been used to monitor the northern gamma -ray sky at energies ...above 0.3 TeV from 2007 November to 2013 January. In this paper, we present the results of a sky survey in the declination band from -10degrees to 70degrees, using data recorded over the past five years. With an integrated sensitivity ranging from 0.24 to ~1 Crab units depending on the declination, six sources have been detected with a statistical significance greater than five standard deviations. Several excesses are also reported as potential gamma -ray emitters. The features of each source are presented and discussed. Additionally, 95% confidence level upper limits of the flux from the investigated sky region are shown. Specific upper limits for 663 GeV gamma -ray active galactic nuclei inside the ARGO-YBJ field of view are reported. The effect of the absorption of gamma -rays due to the interaction with extragalactic background light is estimated.
It is widely known that humans have a tendency to imitate each other and that appropriate modulation of automatic imitative behaviors has a crucial function in social interactions. Gilles de la ...Tourette syndrome (GTS) is a childhood-onset neuropsychiatric disorder characterized by motor and phonic tics. Apart from tics, patients with GTS are often reported to show an abnormal tendency to automatically imitate others' behaviors (i.e., echophenomena), which may be related to a failure in top-down inhibition of imitative response tendencies. The aim of the current study is to explore the top-down inhibitory mechanisms on automatic imitative behaviors in youngsters with GTS. Error rates and reaction times from 32 participants with GTS and 32 controls were collected in response to an automatic imitation task assessing the influence of observed movements displayed in the first-person perspective on congruent and incongruent motor responses. Results showed that participants with GTS had higher error rates than controls, and their responses were faster than those of controls in incompatible stimuli. Our findings provide novel evidence of a key difference between youngsters with GTS and typically developing participants in the ability to effectively control the production of own motor responses to sensory inputs deriving from observed actions.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The scientific community considers the improper use of antimicrobials in farm animals among the causes of the insurgent bacterial resistance contributing to the wider pool of resistance at the ...animal/human interface with serious public health implications. The present study aims to describe the current perceptions regarding antimicrobial use (AMU) and resistance (AMR) and the prescribing behaviour of two different target groups: cattle and pig veterinary practitioners working in Italy. A semi-structured questionnaire was designed and administered using the Computer-Assisted Web Interviewing method. Among the 789 participants who completed the questionnaire, 53.5% and 12.2% were cattle and pig veterinarians, respectively. Differences between the two groups emerged in their opinions concerning different topics. For example, 69.4% and 85.8% of cattle veterinarians claimed to 'somewhat or strongly agree' with the statements 'prescribing broad-spectrum antibiotics in rearing farms increases AMR' and 'the preventive use of antibiotics fosters the development of AMR', against the observed 59.4% and 69.8% of pig veterinarians (p = .050 and p = .000, respectively). Moreover, 26% of pig veterinarians claimed to 'somewhat or strongly agree' with the statement 'alternative methods currently available could be an efficient alternative to antimicrobial treatment', against 16.1% of cattle veterinarians (p = .022). At the same time, no differences between the two groups emerged regarding the danger inadequate AMU in animals poses on both animal and human health. From collected data, the need to provide appropriate training strategies with the aim of adopting a behaviour more consistent with the guidelines for prudent AMU in cattle and pig production systems has emerged.
HIGHLIGHTS
85.8% of cattle vs. 69.8% of pig veterinarians agreed with the statement 'the preventive use of antibiotics fosters the development of AMR'.
64.5% of cattle and 69.1% of pig veterinarians declared they suggest/prescribe alternative approaches to the use of antimicrobials.
'Hygiene-biosecurity-management' and 'nutritive principles' are the alternative strategies most suggested by cattle and pig veterinarians, respectively.
The ARGO-YBJ air shower detector monitored the Crab Nebula gamma-ray emission from 2007 November to 2013 February. The integrated signal, consisting of ~3.3 x 10 super(5) events, reached the ...statistical significance of 21.1 standard deviations. The obtained energy spectrum in the energy range 0.3-20 TeV can be described by a power law function dN/dE = I sub(0) (E/2 TeV) super(-alpha), with a flux normalization I sub(0) = (5.2 + or - 0.2) x 10 super(-12) photons cm super(-2) s super(-1) TeV super(-1) and alpha = 2.63 + or - 0.05, corresponding to an integrated flux above 1 TeV of 1.97 x 10 super(-11) photons cm super(-2) s super(-1). The systematic error is estimated to be less than 30% for the flux normalization and 0.06 for the spectral index. Assuming a power law spectrum with an exponential cutoff dN/dE = I sub(0) (E/2 TeV) super(-alpha) exp (-E/E sub(cut)), the lower limit of the cutoff energy E sub(cut) is 12 TeV, at 90% confidence level. Our extended data set allows the study of the TeV emission over long timescales. Over five years, the light curve of the Crab Nebula in 200-day bins is compatible with a steady emission with a probability of 7.3 x 10 super(-2). A correlated analysis with Fermi-LAT data over ~4.5 yr using the light curves of the two experiments gives a Pearson correlation coefficient r = 0.56 + or - 0.22. Concerning flux variations on timescales of days, a "blind" search for flares with a duration of 1-15 days gives no excess with a significance higher than four standard deviations. The average rate measured by ARGO-YBJ during the three most powerful flares detected by Fermi-LAT is 205 + or - 91 photons day super(-1), consistent with the average value of 137 + or - 10 day super(-1).
A correlation between the secondary cosmic ray flux and the near-earth electric field intensity, measured during thunderstorms, has been found by analyzing the data of the ARGO-YBJ experiment, a full ...coverage air shower array located at the Yangbajing Cosmic Ray Laboratory (4300 m a. s. l., Tibet, China). The counting rates of showers with different particle multiplicities (m=1, 2, 3, and ≥4) have been found to be strongly dependent upon the intensity and polarity of the electric field measured during the course of 15 thunderstorms. In negative electric fields (i.e., accelerating negative charges downwards), the counting rates increase with increasing electric field strength. In positive fields, the rates decrease with field intensity until a certain value of the field EFmin (whose value depends on the event multiplicity), above which the rates begin increasing. By using Monte Carlo simulations, we found that this peculiar behavior can be well described by the presence of an electric field in a layer of thickness of a few hundred meters in the atmosphere above the detector, which accelerates/decelerates the secondary shower particles of opposite charge, modifying the number of particles with energy exceeding the detector threshold. These results, for the first time to our knowledge, give a consistent explanation for the origin of the variation of the electron/positron flux observed for decades by high altitude cosmic ray detectors during thunderstorms.
Abstract Helminths are endoparasites that infect a variety of bird species. Endoparasite infections can cause severe diseases, including kill captive avian hosts and represents a problem to ...maintenance and conservation. The eggs and larval forms of these parasites are usually eliminated in the host feces. The main interest of this study is to report the occurrence of eggs and oocysts in feces from captive wild birds in Goiânia Zoo and free-living birds in its surroundings. The fecal samples were subjected to parasitological examination to identify the presence of helminths and to classify their eggs based on morphological characteristics. Eggs of nematode parasites (Positive/N) were identified as Ascaridia spp. in Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) and Rhea americana (2/2); Ascarididae in Pavo cristatus nigripensis (1/1); Capillaria spp. in Ara chloropterus (1/1) and Penelope jacucaca (1/1); Capillaria plagiaticia in Anodorhynchus hyacinthinus (1/2) and Ara spp. (2/2); Capillaria venusta in Rhamphastus tucanus (1/2); and unidentified nematode eggs from Amazona amazonica (2/2). Eimeria spp. oocyst was founded in feces from A. hyacinthinus (1/2). Considering free-living birds, Diphyllobothrium spp. eggs were founded in Ardea alba (2/2) and Nycticorax nycticorax (2/3). Co-infection of Eustrongylides spp. was founded in A. alba (1/2). This is the first occurrence of: Ascaridia spp. parasitizing B. chiriri; and C. venusta parasitizing R. tucanus. In conclusion, the helminth eggs found in the abovementioned host bird species are consistent with those reported in the literature, and treatment and control protocols were based on their identification.
Resumo Helmintos são endoparasitas que infectam uma variedade de espécies de aves. As infecções por endoparasitas podem causar doenças graves, podendo matar aves em cativeiro e representam um problema de manutenção e conservação. Os ovos e as formas larvais desses parasitas são geralmente eliminados nas fezes do hospedeiro. O principal objetivo deste estudo é relatar a ocorrência de ovos e oocistos em fezes de aves silvestres em cativeiro no Zoológico de Goiânia e em aves de vida livre em seu entorno. As amostras fecais foram submetidas a exame parasitológico para identificação da presença de helmintos e classificação dos ovos com base nas características morfológicas. Ovos de nematóides (Positivo/N) foram identificados como Ascaridia spp. em Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) e Rhea americana (2/2); Ascarididae em Pavo cristatus nigripensis (1/1); Capillaria spp. em Ara chloropterus (1/1) e Penelope jacucaca (1/1); Capillaria plagiaticia em Anodorhynchus hyacinthinus (1/2) e Ara spp. (2/2); Capillaria venusta em Rhamphastus tucanus (1/2); e ovos de nematóide não identificado de Amazona amazonica (2/2). Oocistos de Eimeria spp. foram encontrados nas fezes de A. hyacinthinus (1/2). Considerando pássaros de vida livre, ovos de Diphyllobothrium spp. foram encontrados em Ardea alba (2/2) e Nycticorax nycticorax (2/3). Coinfecção de Eustrongylides spp. foi encontradada em A. alba (1/2). Esta é a primeira ocorrência de: Ascaridia spp. parasitando B. chiriri; e C. venusta parasitando R. tucanus. Em conclusão, os ovos de helmintos encontrados nas espécies de aves hospedeiras acima mencionadas são consistentes com os relatados na literatura, e os protocolos de tratamento e controle foram baseados em sua identificação.
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