Expression of recombinant Araraquara Hantavirus nucleoprotein in insect cells and its use as an antigen for immunodetection compared to the same antigen expressed in Escherichia coli

Background: Antigens for Hantavirus serological tests have been produced using DNA recombinant technology for more than twenty years. Several different strategies have been used for that purpose. All of them avoid the risks and difficulties involved in multiplying Hantavirus in the laboratory. In Brazil, the Araraquara virus is one of the main causes of Hantavirus Cardio-Pulmonary Syndrome (HCPS). Methods: In this investigation, we report the expression of the N protein of the Araraquara Hantavirus in a Baculovirus Expression System, the use of this protein in IgM and IgG ELISA and comparison with the same antigen generated in E. coli. Results: The protein obtained, and purified in a nickel column, was effectively recognized by antibodies from confirmed HCPS patients. Comparison of the baculovirus generated antigen with the N protein produced in E. coli showed that both were equally effective in terms of sensitivity and specificity. Conclusions: Our results therefore indicate that either of these proteins can be used in serological tests in Brazil.

Observation of the suppression of the flux of cosmic rays above 4x10(19) eV

The energy spectrum of cosmic rays above 2.5 x 10(18) eV, derived from 20 000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional to E(-gamma), at energies between 4 x 10(18) eV and 4 x 10(19) eV is 2.69 +/- 0.02(stat) +/- 0.06(syst), steepening to 4.2 +/- 0.4(stat) +/- 0: 06 (syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min.

Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C. L. is E(nu)(2)dN(nu tau)/dE(nu) < 1: 3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu) < 2 x 10(19) eV.

Measurement of the depth of maximum of extensive air showers above 10(18) eV

We describe the measurement of the depth of maximum, X(max), of the longitudinal development of air showers induced by cosmic rays. Almost 4000 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 d24 +/- 3 g/cm(2)/ecade 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.

Characterisation of electric arc furnace dust generated during plain carbon steel production

Electric arc furnace (EAF) dust is a waste generated in the EAF during the steel production process. Among different wastes, EAF dust represents one of the most hazardous, since it contains heavy metals such as Zn, Fe, Cr, Cd and Pb. The goal of the present work is to characterise the waste through chemical analysis, particle size distribution, X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy detection and thermal analysis. The waste sample is composed essentially of spherical particles and has a very small particle size and the majority of the identified elements were Fe, Zn, Ca, Cr, Mn, K and Si. The XRD has presented compounds such as ZnO, ZnFe2O4, Fe2O3, MnO, SiO2, FeFe2O4 and MnAl2O4. According to the thermal analysis results, up to 1000 degrees C the total weight loss was similar to 5%. The results of waste characterisation are very important to these further investigations.

Antileishmanial Sesquiterpenes from the Brazilian Red Alga Laurencia dendroidea

Investigation of the bioactive crude extracts from two populations of the red alga Laurencia dendroidea from the southeastern Brazilian coast led to the identification of five sesquiterpenes: (+)-obtusane (1), a triquinane derivative (2), (-)-elatol (3), obtusol (4), and cartilagineol (5). An antileishmanial bioassay against Leishmania amazonensis was conducted for crude lipophilic extracts and for sesquiterpenes 2, 3, and 4. Compounds 3 and 4 displayed in vitro and in vivo leishmanicidal activity and very low cytotoxicity.

Gas streaming motions towards the nucleus of M81

We present two-dimensional stellar and gaseous kinematics of the inner 120 x 250 pc2 of the LINER/Seyfert 1 galaxy M81, from optical spectra obtained with the Gemini Multi-Object Spectrograph (GMOS) integral field spectrograph on the Gemini-North telescope at a spatial resolution of approximate to 10 pc. The stellar velocity field shows circular rotation and, overall, is very similar to the published large-scale velocity field, but deviations are observed close to the minor axis which can be attributed to stellar motions possibly associated with a nuclear bar. The stellar velocity dispersion of the bulge is 162 +/- 15 km s-1, in good agreement with previous measurements and leading to a black hole mass of M(BH) = 5.5+3.6(-2.0) x 107 M(circle dot) based on the M(BH)-Sigma relationship. The gas kinematics is dominated by non-circular motions and the subtraction of the stellar velocity field reveals blueshifts of approximate to-100 km s-1 on the far side of the galaxy and a few redshifts on the near side. These characteristics can be interpreted in terms of streaming towards the centre if the gas is in the plane. On the basis of the observed velocities and geometry of the flow, we estimate a mass inflow rate in ionized gas of approximate to 4.0 x 10-3 M(circle dot) yr-1, which is of the order of the accretion rate necessary to power the LINER nucleus of M81. We have also applied the technique of principal component analysis (PCA) to our data, which reveals the presence of a rotating nuclear gas disc within approximate to 50 pc from the nucleus and a compact outflow, approximately perpendicular to the disc. The PCA combined with the observed gas velocity field shows that the nuclear disc is being fed by gas circulating in the galaxy plane. The presence of the outflow is supported by a compact jet seen in radio observations at a similar orientation, as well as by an enhancement of the [O i]/H alpha line ratio, probably resulting from shock excitation of the circumnuclear gas by the radio jet. With these observations we are thus resolving both the feeding - via the nuclear disc and observed gas inflow, and the feedback - via the outflow, around the low-luminosity active nucleus of M81.

Taxonomic Identity in Microbial Eukaryotes: A Practical Approach Using the Testate Amoeba Centropyxis to Resolve Conflicts Between Old and New Taxonomic Descriptions

The present work focuses on 12 taxa of the genus Centropyxis Stein, 1857 to explore the conflict between traditional and contemporary taxonomic practices. We examined the morphology, biometry, and ecology of 2,120 Centropyxis individuals collected from Tiete River, Sao Paulo, Brazil; with these new data we studied the consistency of previously described species, varieties, and forms. We encountered transitional forms of test morphology that undermine specific and varietal distinctions for three species and nine varieties. Biometrical analyses made comparing the organisms at the species level suggest a lack of separation between Centropyxis aculeata and Centropyxis discoides, and a possible distinction for Centropyxis ecornis based on spine characteristics. However, incongruence between recent and previous surveys makes taking any taxonomic-nomenclatural actions inadvisable, as they would only add to the confusion. We suggest an explicit and objective taxonomic practice in order to enhance our taxonomic and species concepts for microbial eukaryotes. This will allow more precise inferences of taxon identity for studies in other areas.

Upper limit on the cosmic-ray photon flux above 10(19) eV using the surface detector of the Pierre Auger Observatory

A method is developed to search for air showers initiated by photons using data recorded by the surface detector of the Auger Observatory. The approach is based on observables sensitive to the longitudinal shower development, the signal risetime and the curvature of the shower front. Applying this method to the data, tipper limits on the flux of photons of 3.8 x 10(-3), 2.5 x 10(-3), and 2.2 x 10(-3) km(-2) sr(-1) yr(-1) above 10(19) eV, 2 x 10(19) eV, and 4 x 10(19) eV are derived, with corresponding limits on the fraction of photons being 2.0%, 5.1%, and 31% (all limits at 95% c.l.). These photon limits disfavor certain exotic models of sources of cosmic rays. The results also show that the approach adopted by the Auger Observatory to calibrate the shower energy is not strongly biased by a contamination from photons. (C) 2008 Elsevier B.V. All rights reserved.

Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei

Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the highest-energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [Pierre Auger Collaboration, Science 318 (2007) 938]. The correlation has maximum significance for cosmic rays with energy greater than similar to 6 x 10(19) eV and AGN at a distance less than similar to 75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified a priori, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest-energies originate from extra-galactic sources close enough so that their flux is not significantly attenuated by interaction with the cosmic background radiation (the Greisen-Zatsepin-Kuz`min effect). The angular scale of the correlation observed is a few degrees, which suggests a predominantly light composition unless the magnetic fields are very weak outside the thin disk of our galaxy. Our present data do not identify AGN as the sources of cosmic rays unambiguously, and other candidate sources which are distributed as nearby AGN are not ruled out. We discuss the prospect of unequivocal identification of individual sources of the highest-energy cosmic rays within a few years of continued operation of the Pierre Auger Observatory. (C) 2008 Elsevier B.V. All rights reserved.

X-ray transmission through nanostructured and microstructured CuO materials

This study presents a comparison of the X-ray transmission through microsized and nanosized materials. For this purpose CuO nanoparticles, with 13.4 nm average grain size, and CuO microparticles, with a mean particle size of 56 mu m, were incorporated separately to beeswax in a concentration of 5%. Results show that the transmission through the above material plates with microsized and nanosized CuO was almost the same for X-ray beams generated at 60 and 102 kV tube voltages. However, for the radiation beams generated at 26 and 30 kV tube voltages the X-rays are more attenuated by the nanostructured CuO plates by a factor of at least 14%. Results suggest that the difference in the low energy range may be due to the higher number of particles/gram in the plates designed with CuO nanoparticles and due to the grain size effect on the X-ray transmission. (C) 2010 Elsevier Ltd. All rights reserved.

Coherent states of a particle in a magnetic field and the Stieltjes moment problem

A solution to a version of the Stieltjes moment. problem is presented. Using this solution, we construct a family of coherent states of a charged particle in a uniform magnetic field. We prove that these states form an overcomplete set that is normalized and resolves the unity. By the help of these coherent states we construct the Fock-Bergmann representation related to the particle quantization. This quantization procedure takes into account a circle topology of the classical motion. (C) 2009 Elsevier B.V. All rights reserved.

Trigger and aperture of the surface detector array of the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection of EAS with energy above 3 x 10(18) eV, for all zenith angles between 0 degrees and 60 degrees, independently of the position of the impact point and of the mass of the primary particle. In these range of energies and angles, the exposure of the surface array can be determined purely on the basis of the geometrical acceptance. (C) 2009 Elsevier B.V. All rights reserved.

The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays

Since data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found.

The exposure of the hybrid detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The ""hybrid"" detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data collected during operations, such as the status of the fluorescence detector, background light and atmospheric conditions, that are used in both simulation and reconstruction. (C) 2010 Elsevier B.V. All rights reserved.