1,264 research outputs found
Uso de forrageiras tropicais em sistemas de sucessão com a soja e sua relação com qualidade fÃsica do solo na região do basalto paranaense.
Abundância e diversidade da macrofauna do solo em diferentes fases de um sistema de integração lavoura-pecuária no arenito paranaense.
A macrofauna do solo exerce importante papel na ciclagem de nutrientes e agregação do solo, pois é responsável pela fragmentação dos resÃduos orgânicos, mistura das partÃculas minerais e orgânicas, redistribuição da matéria orgânica e abertura de canais (bioporos). A abundância e diversidade da macrofauna do solo foram avaliadas em áreas submetidas a diferentes fases de um sistema de integração lavoura-pecuária, implantado em 2006, em Jardim Olinda/PR, sobre um Latossolo Vermelho arenoso (110 g kg-1 de argila). A área foi dividida em quatro módulos de 6 ha: P01 ? pasto/pasto/pasto/pasto/soja; P02 ? pousio/braquiária safrinha/ soja/milho + braquiária/soja; P03 ? pousio/milho + braquiária/soja/milho + braquiária/pasto; e P04 ? pousio/milho + braquiária/pasto/pasto/pasto. A espécie de braquiária utilizada na pastagem e no consórcio com o milho foi a Brachiaria brizantha cv. ?Xaraes?. Os módulos caracterizados por uma maior proporção de culturas anuais de grãos (P02 e P03) apresentaram menor abundância e diversidade da macrofauna em relação ao P01 e P04, explorados com pastagens perenes por mais tempo. O módulo P04 caracterizou-se por uma menor abundância total de organismos da macrofauna do solo em comparação ao P01, sendo essa diferença associada à densidade populacional de oligoquetas. Esses dois módulos apresentaram similaridade em relação à diversidade da macrofauna. Assim, concluiu-se que o uso de forrageiras tropicais em sistemas de integração lavoura-pecuária melhora a qualidade biológica do solo em termos da abundância e diversidade da macrofauna
Sub-milliarcsecond Imaging of Quasars and AGN
We have used the VLBA at 15 GHz to image the structure of 132 strong compact
AGN and quasars with a resolution better than one milliarcsecond and a dynamic
range typically exceeding 1000 to 1. These observations were made as part of a
program to investigate the sub-parsec structure of quasars and AGN and to study
the changes in their structure with time. Many of the sources included in our
study, particularly those located south of +35 degrees, have not been
previously imaged with milliarcsecond resolution. Each of the sources has been
observed at multiple epochs. In this paper we show images of each of the 132
sources which we have observed. For each source we present data at the epoch
which had the best quality data. The milliarcsecond jets generally appear
one-sided but two-sided structure is often found in lower luminosity radio
galaxies and in high luminosity quasars with gigahertz peaked spectra. Usually
the structure is unresolved along the direction perpendicular to the jet, but a
few sources have broad plumes. In some low luminosity radio galaxies, the
structure appears more symmetric at 2 cm than at long wavelengths. The apparent
long wavelength symmetry in these sources is probably due to absorption by
intervening material. A few sources contain only a single component with any
secondary feature at least a thousand times weaker. We find no obvious
correlation of radio morphology and the detection of gamma-ray emission by
EGRET.Comment: 19 pages, 3 tables, 3 figures. Figure 2 (132 contour diagrams) is
long and is omitted here. Figure 2 may be viewed at
http://www.cv.nrao.edu/2cmsurvey/ In press, Astronomical Journal, April 199
Sudan Black B treatment reduces autofluorescence and improves resolution of in situ hybridization specific fluorescent signals of brain sections
Interference by autofluorescence is one of the major concerns of immunofluorescence analysis of in situ hybridization-based diagnostic assays. We present a useful technique that reduces autofluorescent background without affecting the tissue integrity or direct immunofluorescence signals in brain sections. Using six different protocols, such as ammonia/ethanol, Sudan Black B (SBB) in 70% ethanol, photobleaching with UV light and different combinations of them in both formalin-fixed paraffin-embedded and frozen human brain tissue sections, we have found that tissue treatment of SBB in a concentration of 0.1% in 70% ethanol is the best approach to reduce/eliminate tissue autofluorescence and background, while preserving the specific fluorescence hybridization signals. This strategy is a feasible, non-time consuming method that provides a reasonable compromise between total reduction of the tissue autofluorescence and maintenance of specific fluorescent labels.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2007/56146-2]Comissao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)[1429/08-6
Jet Collimation in Action: Re-alignment on Kiloparsec Scales in 3C279
We report a change in the trajectory of a well studied jet component of the
quasar 3C279. The component changes in apparent projected speed and direction,
and we find it to be moving with a Lorentz factor gamma >~ 15 at an initial
angle of <~ 1 degree to the line of sight. The new trajectory of the component
has approximately the same speed and direction as an earlier superluminal
feature, originally seen in the early 1970s. The new direction for the
component is also much better aligned with larger scale VLBA and VLA structure
out to 0.1 arcseconds. We suggest that the trajectory change is a collimation
event occurring at >~ 1 kiloparsec (deprojected) along the jet. While the
change in trajectory on the sky appears to be 26 degrees the intrinsic change
is <~ 1 degree. We estimate the Doppler factor prior to the change in direction
to be D >~ 28 and after the change to be D >~ 23. Comparison to independent
constraints on the Doppler factor suggest that the energy in the radiating
particles cannot greatly exceed the energy in the magnetic field unless the
volume filling factor is very much less than one.Comment: 4 pages, 4 figures, Accepted by ApJ Letters. Replaced version adds a
comment to the discussio
High treatment failure and default rates for patients with multidrug-resistant tuberculosis in KwaZulu-Natal, South Africa, 2000–2003.
SETTING: Multidrug-resistant tuberculosis (MDR-TB) has emerged as a significant public health threat in South Africa. OBJECTIVE: To describe treatment outcomes and determine risk factors associated with unfavorable outcomes among MDR-TB patients admitted to the provincial TB referral hospital in KwaZulu-Natal Province, South Africa. DESIGN: Retrospective observational study of MDR-TB patients admitted from 2000 to 2003. RESULTS: Of 1209 MDR-TB patients with documented treatment outcomes, 491 (41%) were cured, 35 (3%) completed treatment, 208 (17%) failed treatment, 223 (18%) died and 252 (21%) defaulted. Of the total number of patients with known human immunodeficiency virus (HIV) status, 52% were HIV-infected. Treatment failure, death and default each differed in their risk factors. Greater baseline resistance (aOR 2.3-3.0), prior TB (aOR 1.7), and diagnosis in 2001, 2002 or 2003 (aOR 1.9-2.3) were independent risk factors for treatment failure. HIV co-infection was a risk factor for death (aOR 5.6), and both HIV (aOR 2.0) and male sex (aOR 1.9) were risk factors for treatment default. CONCLUSION: MDR-TB treatment outcomes in KwaZulu-Natal were substantially worse than those published from other MDR-TB cohorts. Interventions such as concurrent antiretroviral therapy and decentralized MDR-TB treatment should be considered to improve MDR-TB outcomes in this high HIV prevalence setting
Pre-implant magnetic resonance and transrectal ultrasound imaging in high-dose-rate prostate brachytherapy : comparison of prostate volumes, craniocaudal extents, and contours
Purpose: The purpose of this study was to compare the prostate contours drawn by two radiation oncologists and one radiologist on magnetic resonance (MR) and transrectal ultrasound (TRUS) images. TRUS intra- and inter-fraction variability as well as TRUS vs. MR inter-modality and inter-operator variability were studied. Material and methods: Thirty patients affected by localized prostate cancer and treated with interstitial high-dose-rate (HDR) prostate brachytherapy at the National Cancer Institute in Milan were included in this study. Twenty-five patients received an exclusive two-fraction (14 Gy/fraction) treatment, while the other 5 received a single 14 Gy fraction as a boost after external beam radiotherapy. The prostate was contoured on TRUS images acquired before (virtual US) and after (real US) needle implant by two radiation oncologists, whereas on MR prostate was independently contoured by the same radiation oncologists (MR1, MR2) and by a dedicated radiologist (MR3). Absolute differences of prostate volumes ( 06V) and craniocaudal extents ( 06dz) were evaluated. The Dice's coefficient (DC) was calculated to quantify spatial overlap between MR contours. Results: Significant difference was found between Vvirtual and Vlive (p < 0.001) for the first treatment fractions and between VMR1 and VMR2 (p = 0.043). Significant difference between cranio-caudal extents was found between dzvirtual and dzlive (p < 0.033) for the first treatment fractions, between dzvirtual of the first treatment fractions and dzMR1 (p < 0.001) and between dzMR1 and dzMR3 (p < 0.01). Oedema might be responsible for some of the changes in US volumes. Average DC values resulting from the comparison MR1 vs. MR2, MR1 vs. MR3 and MR2 vs. MR3 were 0.95 \ub1 0.04 (range, 0.82-0.99), 0.87 \ub1 0.04 (range, 0.73-0.91) and 0.87 \ub1 0.04 (range, 0.72-0.91), respectively. Conclusions: Our results demonstrate the importance of a multiprofessional approach to TRUS-guided HDR prostate brachytherapy. Specific training in MR and US prostate imaging is recommended for centers that are unfamiliar with HDR prostate brachytherapy
- …