539 research outputs found
Nuclear Activity in Circumnuclear Ring Galaxies
We have analyzed the frequency and properties of the nuclear activity in a
sample of galaxies with circumnuclear rings and spirals (CNRs). This sample was
compared with a control sample of galaxies with very similar global properties
but without circumnuclear rings. We discuss the relevance of the results in
regard to the AGN feeding processes and present the following results: (i)
bright companion galaxies seem not to be important for the appearance of CNRs,
which appear to be more related to intrinsic properties of the host galaxies or
to minor merger processes; (ii) the proportion of strong bars in galaxies with
an AGN and a CNR is somewhat higher than the expected ratio of strongly barred
AGN galaxies from the results of Ho and co-workers; (iii) the incidence of
Seyfert activity coeval with CNRs is clearly larger than the rate expected from
the morphological distribution of the host galaxies; (iv) the rate of Sy 2 to
Sy 1 type galaxies with CNRs is about three times larger than the expected
ratio for galaxies without CNRs and is opposite to that predicted by the
geometric paradigm of the classical unified model for AGNs, although it does
support the hy-pothesis that Sy 2 activity is linked to circumnuclear star
formation. The possible selection effects of the sample are discussed, and we
conclude that the detected trends are strong enough to justify high quality
observations of as large as possible sets of galaxies with circumnuclear rings
and their matched control samples.Comment: Submitted to International Journal of Astronomy and Astrophysic
Kinematics and Modeling of the Inner Region of M83
Two-dimensional kinematics of the central region of M 83 (NGC 5236) were
obtained through three-dimensional NIR spectroscopy with Gemini South
telescope. The spatial region covered by the integral field unit (~5" x 13" or
~90 x 240 pc), was centered approximately at the center of the bulge isophotes
and oriented SE-NW. The Pa_beta emission at half arcsecond resolution clearly
reveals spider-like diagrams around three centers, indicating the presence of
extended masses, which we describe in terms of Satoh distributions. One of the
mass concentrations is identified as the optical nucleus (ON), another as the
center of the bulge isophotes, similar to the CO kinematical center (KC), and
the third as a condensation hidden at optical wavelengths (HN), coincident with
the largest lobe in 10 micron emission. We run numerical simulations that take
into account ON, KC and HN and four more clusters, representing the star
forming arc at the SW of the optical nucleus. We show that ON, KC and HN suffer
strong evaporation and merge in 10-50 Myr. The star-forming arc is scattered in
less than one orbital period, also falling into the center. Simulations also
show that tidal-striping boosts the external shell of the condensations to
their escape velocity. This fact might lead to an overestimation of the mass of
the condensations in kinematical observations with spatial resolution smaller
than the condensations' apparent sizes. Additionally the existence of two ILR
resonances embracing the chain of HII regions, claimed by different authors,
might not exist due to the similarity of the masses of the different components
and the fast dynamical evolution of M83 central 300 pc
Seletividade de Metarhizium anisopliae à Telenomus podisi (Hymenoptera: Scelionidae).
Telenomus podisi e Metarhizium anisopliae são agentes de controle biológico que ocorrem ou podem ser utilizados conjuntamente. Entretanto, estudos de compatibilidade entre parasitoides e fungos entomopatogênicos são escassos. O objetivo deste trabalho foi avaliar a seletividade do fungo M. anisopliae a adultos do parasitoide de ovos T. podisi. Suspensões de M. anisopliae (1,0×109 conídios/ml) foram pulverizadas sobre placas de vidro em Torre de Potter e secas à temperatura ambiente, formando uma película. Como testemunha foi utilizada água destilada estéril + Tween 80 (0,01%). As placas de vidro pulverizadas foram utilizadas na construção de gaiolas de exposição (IOBC) e em seu interior foram liberados adultos de T. podisi com 24 h de idade. As gaiolas foram mantidas em condições controladas de temperatura, umidade e fotoperiodo (25±1º C, 80% UR, 14 h) e os parasitóides foram alimentados com mel. Cartelas contendo ovos de Euschistus heros foram oferecidas às fêmeas de T. podisi 24 h, 48 h, 72 h e 144 h após a pulverização e, sendo posteriormente, acondicionadas em sacos plásticos para avaliar a porcentagem de parasitismo e viabilidade dos parasitoides. Os resultados obtidos indicam que mesmo com as aplicações de M. anisopliae, o parasitismo e a viabilidade foram superiores a 70%, mostrando que o fungo é seletivo aos adultos de T. podisi, sendo classificado como inócuo (classe 1), de acordo com a IOBC, e portanto, ambos os agentes de controle biológico podem ser utilizados no Manejo Integrado de Pragas.SICONBIOL 2011
Efeito de Metarhizium anisopliae ASH. sobre Telenomus podisi (Hymenoptera: scelionidae).
Os agentes de controle biológico Metarhizium anisopliae e Telenomus podisi são empregados no controle de populações de pragas. Porém na literatura são citados casos de interferência entre agentes de controle. Para serem utilizados concomitantemente, a compatibilidade entre o fungo entomopatogênico e o parasitoide deve ser elucidada. O objetivo deste trabalho foi avaliar os possíveis efeitos do fungo M. anisopliae na eficiência do parasitoide de ovos T. podisi. Os bioensaios foram conduzidos em duas etapas, utilizando ovos não parasitados e ovos parasitados. Na primeira etapa, ovos de Euschistus heros esterilizados aderidos a cartelas (1×2 cm), receberam aplicações de 1,5 ml de suspensão de M. anisopliae (1,0×1010 conídios/ml), em torre de Potter, sendo posteriormente expostos ao parasitismo. Na segunda etapa, suspensões de (1,0×109 conídios/ml) foram pulverizados sobre ovos parasitados. A testemunha recebeu água destilada estéril + Tween 80 (0,01%) em ambos os ensaios. Após as pulverizações, as cartelas foram inseridas em gaiolas de exposição padronizadas pela (IOBC), mantidas em condições controladas de temperatura, umidade e fotoperiodo (25±1º C, 80%, 14:10). Os parasitoides foram alimentados com mel. Para avaliar a porcentagem de parasitismo, emergência e viabilidade dos parasitóides, as cartelas de ovos contendo os parasitoides foram acondicionadas em sacos plásticos, posteriormente observadas em lupa estereoscópica para quantificação e calculo dos parâmetros estudados, Os resultados obtidos indicam que M. anisopliae não afeta o parasitismo de T. podisi, porém a emergência do parasitoide pode ser reduzida quando o fungo é aplicado sobre ovos previamente parasitados. Possivelmente, houve alguma atividade dos fungos sobre os ovos de E. heros que impediram a emergência de T. podisi e fatores físicos e bioquímicos podem estar envolvidos durante a infecção e penetração pelo córion. Entretanto, a redução da viabilidade do parasitismo quando o fungo foi aplicado em ovos parasitados foi percentualmente pequena. Por tanto, M. anisopliae é inócuo e seletivo a T. podisi, e ambos podem ser utilizados no manejo de pragas, preferencialmente quando as aplicações do fungo e liberações do parasitoide sejam realizadas em momentos diferentes para conseguir maior eficiência.SICONBIOL 2011
Immunoblot analysis of the seroreactivity to recombinant Borrelia burgdorferi sensu lato antigens, including VlsE, in the long-term course of treated patients with Erythema migrans
Objective: We evaluated whether immunoblotting is capable of substantiating the posttreatment clinical assessment of patients with erythema migrans ( EM), the hallmark of early Lyme borreliosis. Methods: In 50 patients, seroreactivity to different antigens of Borrelia burgdorferi sensu lato was analyzed by a recombinant immunoblot test (IB) in consecutive serum samples from a minimum follow-up period of 1 year. Antigens in the IgG test were decorin- binding protein A, internal fragment of p41 (p41i), outer surface protein C (OspC), p39, variable major protein-like sequence expressed (VlsE), p58 and p100; those in the IgM test were p41i, OspC and p39. Immune responses were correlated with clinical and treatment-related parameters. Results: Positive IB results were found in 50% before, in 57% directly after therapy and in 44% by the end of the follow-up for the IgG class, and in 36, 43 and 12% for the IgM class. In acute and convalescence phase sera, VlsE was most immunogenic on IgG testing 60 and 70%), and p41i (46 and 57%) and OspC (40 and 57%) for the IgM class. By the end of the follow-up, only the anti-p41i lgM response was significantly decreased to 24%. Conclusions: No correlation was found between IB results and treatment-related parameters. Thus, immunoblotting does not add to the clinical assessment of EM patients after treatment. Copyright (c) 2008 S. Karger AG, Basel
TDR Targets: a chemogenomics resource for neglected diseases
The TDR Targets Database (http://tdrtargets.org) has been designed and developed as an online resource to facilitate the rapid identification and prioritization of molecular targets for drug development, focusing on pathogens responsible for neglected human diseases. The database integrates pathogen specific genomic information with functional data (e.g. expression, phylogeny, essentiality) for genes collected from various sources, including literature curation. This information can be browsed and queried using an extensive web interface with functionalities for combining, saving, exporting and sharing the query results. Target genes can be ranked and prioritized using numerical weights assigned to the criteria used for querying. In this report we describe recent updates to the TDR Targets database, including the addition of new genomes (specifically helminths), and integration of chemical structure, property and bioactivity information for biological ligands, drugs and inhibitors and cheminformatic tools for querying and visualizing these chemical data. These changes greatly facilitate exploration of linkages (both known and predicted) between genes and small molecules, yielding insight into whether particular proteins may be druggable, effectively allowing the navigation of chemical space in a genomics context
The Impact of Grounding in Running Shoes on Indices of Performance in Elite Competitive Athletes
The introduction of carbon fiber plate shoes has triggered a plethora of world records in running, which has encouraged shoe industries to produce novel shoe designs to enhance running performance, including shoes containing conductor elements or "grounding shoes" (GS), which could potentially reduce the energy cost of running. The aim of this study was to examine the physiological and perceptual responses of athletes subjected to grounding shoes during running. Ten elite runners were recruited. Firstly, the athletes performed an incremental running test for VO(2)max and anaerobic threshold (AT) determination, and were familiarized with the two shoe conditions (traditional training shoe (TTS) and GS, the latter containing a conductor element under the insole). One week apart, athletes performed running economy tests (20 min run at 80% of the AT) on a 400 m dirt track, with shoe conditions randomized. VO2, heart rate, lactate, and perceived fatigue were registered throughout the experiment. No differences in any of the physiological or perceptual variables were identified between shoe conditions, with an equal running economy in both TTS and GS (51.1 +/- 4.2 vs. 50.9 +/- 5.1 mL kg(-1) min(-1), respectively). Our results suggest that a grounding stimulus does not improve the energy cost of running, or the physiological/perceptual responses of elite athletes
The nearest extreme starburst: bubbles, young star clusters, and outflow in NGC 3256
In this Work we report, for the extreme starburst in the IR merger NGC 3256:
(i) The detection of 4 galactic bubbles, associated with SN explosions.(ii) The
first analysis of the spatial distribution of young star clusters (YSC)
candidates.(iii) The kinematic study of the ionized gas in the core of of the
main optical nucleus, performed with HST STIS spectra. The shape of the
rotation curve and the emission line profile could be explained by the presence
in the core of YSC with outflow.Comment: 5 pages, 5 figures, Contect Replac., accepted MN-RA
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