212 research outputs found
SOIL FAUNA ALONG THE PROCESS OF ECOLOGICAL SUCCESSION IN GULLIES REVEGETATED IN THE MUNICIPALITY OF PINHEIRAL \u2013 RJ
O objetivo do trabalho foi avaliar a diversidade, riqueza e
composi\ue7\ue3o da comunidade da fauna do solo ep\uedgea em uma
vo\ue7oroca revegetada no ano de 2000 com diferentes esp\ue9cies de
leguminosas arb\uf3reas. A vo\ue7oroca est\ue1 localizada no
Instituto Federal de Educa\ue7\ue3o (IFRJ) campus Nilo Pe\ue7anha
no munic\uedpio de Pinheiral \u2013 RJ. Foram avaliadas as seguintes
\ue1reas: plantio de Acacia mangium Willd. (PA), plantio de Mimosa
caesalpiniifolia Benth. (PM), plantio de leguminosas arb\uf3reas no
ter\ue7o superior da encosta (PTS), plantio de leguminosas no
interior da vo\ue7oroca (IVR2000). Os plantios de A. mangium e M.
caesalpiniifolia foram realizados antes da revegeta\ue7\ue3o. Para
efeito comparativo tamb\ue9m foi avaliada uma \ue1rea de floresta
secund\ue1ria com 20 anos, pr\uf3xima ao local de coleta. Na coleta
da fauna do solo ep\uedgea foram utilizadas 10 armadilhas do tipo
pitfall (MOLDENKE, 1994) por \ue1rea. Foram realizadas tr\ueas
coletas, uma no in\uedcio da revegeta\ue7\ue3o, em maio de 2000,
em junho de 2006 e abril de 2008. Houve um aumento no n\ufamero de
grupos e na diversidade da fauna do solo no plantio no ter\ue7o
superior, no interior da vo\ue7oroca, e no plantio de Mimosa
caesalpiniifolia ap\uf3s 6 anos da interven\ue7\ue3o. Nas coletas
realizadas em 2000 e 2006, a APC mostrou que a maioria dos grupos
estava associada ao ano de 2006, mostrando total antagonismo com o ano
de 2000. O plantio de Acacia mangium foi a \ue1rea com o menor
n\ufamero de grupos. Na coleta realizada em 2008, a pastagem foi a
\ue1rea com menor n\ufamero m\ue9dio de grupos coletados e na
an\ue1lise de componentes principais (ACP) do interior da
vo\ue7oroca os grupos estavam associados ao ano de 2008 com total
antagonismo com os anos de 2000 e 2006. Os grupos Formicidae e
Collembola (Entomobryomorpha) foram os mais dominantes em todas as
\ue1reas amostradas no ano de 2000 e 2008 e no interior da
vo\ue7oroca ano de 2006.The diversity, richness and composition of the soil epigeous fauna
community were evaluated in a revegetated gully at the Instituto
Federal de Educa\ue7\ue3o (IFRJ) campus Nilo Pe\ue7anha, in the
municipality of Pinheiral, Rio de Janeiro state. Revegetation was
performed in 2000, and consisted of four different strategies involving
N-fixing trees: planting Acacia mangium Willd. (PA); planting Mimosa
caesalpiniifolia Benth. (PM); on the outer edges of the gully head
(PTS); and planting a mix of legume tree species into the gully
(IVR2000). Acacia mangium and Mimosa caesalpiniifolia were planted
above the gully head. A nearby 20-year secondary forest remnant was
used as a reference site. Ten pitfall traps were used for the sampling
of epigeous fauna at each one of the five areas (MOLDENKE, 1994).
Sampling was performe in May 2000, June 2006, and April 2008. Six years
after revegetation has started, fauna group richness and diversity
increased both into the gully and in Mimosa caesalpiniifolia
plantation. For the 2000 and 2006 samplings a PCA showed that groups
were mostly associated to 2006, and completely opposite to 2000. Acacia
mangium plantation had the lowest group richness. In the 2008 sampling,
pasture showed the lowest group richness, and according to the PCA
groups into the gully were associated to 2008, and completely opposite
to 2000 and 2006. Formicidae and Collembola (Entomobryomorpha) were
dominant in all sampled areas, both in 2000 and 2008, and into the
gully in 2006 as well
Measurement of the top quark mass using the matrix element technique in dilepton final states
We present a measurement of the top quark mass in pp¯ collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. The data were collected by the D0 experiment corresponding to an integrated luminosity of 9.7 fb−1. The matrix element technique is applied to tt¯ events in the final state containing leptons (electrons or muons) with high transverse momenta and at least two jets. The calibration of the jet energy scale determined in the lepton+jets final state of tt¯ decays is applied to jet energies. This correction provides a substantial reduction in systematic uncertainties. We obtain a top quark mass of mt=173.93±1.84 GeV
Associations between back pain across adulthood and spine shape in early old age in a British birth cohort
© 2018, The Author(s). We aimed to examine whether back pain across adulthood was associated with spine shape at age 60–64 years. Data were from 1405 participants in the MRC National Survey of Health and Development, a nationally representative British birth cohort. Back pain was ascertained during nurse interviews at ages 36, 43, 53 and 60–64 years. Cumulative exposure to back pain was then derived by counting the number of ages at which back pain was reported. Statistical shape modelling was used to characterise thoracolumbar spine shape using lateral dual-energy x-ray absorptiometry images which were ascertained at age 60–64 years. Linear regression models were used to test associations of spine shape modes (SM) with: (1) cumulative exposure to back pain; (2) back pain reports during different periods of adulthood. After adjusting for sex, higher cumulative exposure to back pain across adulthood was associated with wedge-shaped L4-5 disc (lower SM4 scores) and smaller disc spaces (higher SM8 scores) in both sexes. In addition, reporting of back pain at ages 53 and/or 60–64 years was associated with smaller L4-5 disc space (lower SM6 scores) in men but not women. These findings suggest that back pain across adulthood may be associated with specific variations in spine shapes in early old age
Observation of the Baryonic Flavor-Changing Neutral Current Decay Lambda_b -> Lambda mu+ mu-
We report the first observation of the baryonic flavor-changing neutral
current decay Lambda_b -> Lambda mu+ mu- with 24 signal events and a
statistical significance of 5.8 Gaussian standard deviations. This measurement
uses ppbar collisions data sample corresponding to 6.8fb-1 at sqrt{s}=1.96TeV
collected by the CDF II detector at the Tevatron collider. The total and
differential branching ratios for Lambda_b -> Lambda mu+ mu- are measured. We
find B(Lambda_b -> Lambda mu+ mu-) = [1.73+-0.42(stat)+-0.55(syst)] x 10^{-6}.
We also report the first measurement of the differential branching ratio of B_s
-> phi mu+ mu- using 49 signal events. In addition, we report branching ratios
for B+ -> K+ mu+ mu-, B0 -> K0 mu+ mu-, and B -> K*(892) mu+ mu- decays.Comment: 8 pages, 2 figures, 4 tables. Submitted to Phys. Rev. Let
The contributions of muscarinic receptors and changes in plasma aldosterone levels to the anti-hypertensive effect of Tulbaghia violacea
Background: Tulbaghia violacea Harv. (Alliaceae) is used to treat various ailments, including hypertension (HTN) in
South Africa. This study aims to evaluate the contributions of muscarinic receptors and changes in plasma
aldosterone levels to its anti-hypertensive effect.
Methods: In the acute experiments, methanol leaf extracts (MLE) of T. violacea (30–120 mg/kg), muscarine (0.16
-10 μg/kg), and atropine (0.02 - 20.48 mg/kg), and/or the vehicle (dimethylsulfoxide (DMSO) and normal saline (NS))
were respectively and randomly administered intravenously in a group of spontaneously hypertensive (SHR)
weighing 300 to 350 g and aged less than 5 months. Subsequently, T. violacea (60 mg/kg) or muscarine (2.5 μg/kg)
was infused into eight SHRs, 20 min after atropine (5.12 mg/kg) pre-treatment. In the chronic (21 days) experiments,
the SHRs were randomly divided into three groups, and given the vehicle (0.2 ml/day of DMSO and NS), T. violacea
(60 mg/kg/day) and captopril (10 mg/kg/day) respectively into the peritoneum, to investigate their effects on blood
pressure (BP), heart rate (HR), and plasma aldosterone levels. Systolic BP and HR were measured using tail-cuff
plethysmography during the intervention. BP and HR were measured via a pressure transducer connecting the
femoral artery and the Powerlab at the end of each intervention in the acute experiment; and on day 22 in the
chronic experiment.
Results: In the acute experiments, T. violacea, muscarine, and atropine significantly (p < 0.05) reduced BP
dose-dependently. T. violacea and muscarine produced dose-dependent decreases in HR, while the effect of
atropine on HR varied. After atropine pre-treatment, dose-dependent increases in BP and HR were observed with
T. violacea; while the BP and HR effects of muscarine were nullified. In the chronic experiments, the T. violaceatreated
and captropril-treated groups had signicantly lower levels of aldosterone in plasma when compared to
vehicle-treated group. Compared to the vehicle-treated group, significant reduction in BP was only seen in the
captopril-treated group; while no difference in HR was observed among the groups.
Conclusion: The results obtained in this study suggest that stimulation of the muscarinic receptors and a reduction
in plasma aldosterone levels contribute to the anti-hypertesive effect of T. violacea.IS
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