539 research outputs found
Composição E Diversidade De Anuros Na Restinga Do Município De Conde, Litoral Norte Do Estado Da Bahia, Nordeste Do Brasil
The Conde municipality is located in the northern coast of the state of Bahia (NC), northeastern Brazil, and is part of the Atlantic Tropical domain. The anuran fauna of the northern portion of the NC is still poorly known if compared to the southern portion. The Restinga is one of the predominant environments of the coastal plains of the NC and it is characterized essentially by presenting sandy soil covered by herbaceous and shrubby vegetation. The objective of this study was to determine the anuran species composition and diversity for the Restinga of the Conde municipality. Sampling was carried out at night by active search over four periods of five consecutive days each, two over the ‘main rainy season’ and two in a ‘lesser rainy season’, using 14 sample units (SUs) and five extra sample plots (EPs). We calculated dominance and species diversity using the Berger-Parker and Shannon-Wiener H’ indices, respectively. We used accumulation curves and the Jackknife 1 estimator to estimate anuran species richness, considering only the data obtained from the SUs. We recorded 713 anuran specimens distributed within 33 species, 13 genera and five families (Bufonidae, Craugastoridae, Hylidae, Leptodactylidae and Microhylidae). The Hylidae and Leptodactylidae families had the highest species richness. Considering only the SUs (Jackknife 1 estimator in brackets), we recorded 28 species in the study area (33.9 ± 2.3), 13 in Shrubby Vegetation Zones-SVZ (20.8 ± 2.9) and 25 in Freshwater Wetland Zones-FWZ (28.9 ± 1.9). The abundance and species diversity of the FWZ (n = 638 specimens; H’= 2.4) were higher than those recorded for the SVZ (n = 52 specimens; H’ = 1.9). The SVZ and FWZ showed distinct dominant species, wherein Pristimantis paulodutrai was the dominant species in SVZ and Scinax fuscomarginatus in FWZ. The Restinga of the Conde municipality stands out as the one with the highest anuran species richness already recorded considering only SVZ and FWZ. Moreover, its anuran species composition represented 55% of the anuran species known for the NC and included taxa common to three different morphoclimatic domains (Tropical Atlantic, Cerrado and Caatinga). © 2016, Universidade Estadual de Campinas UNICAMP. All rights reserved.16
Search for tau -> e gamma decay at Belle
We have searched for the lepton-flavor-violating decay tau -> e gamma using a
data sample of 86.7/fb collected with the Belle detector at the KEKB asymmetric
e^+ e^- collider. No evidence for a signal is obtained, and we set an upper
limit for the branching fraction Br(tau -> e gamma) < 3.9 x 10^-7 at the 90%
C.L.Comment: 11 pages, 10 figures, ReVTeX4, eps
Determination of |Vcb| using the semileptonic decay \bar{B}^0 --> D^{*+}e^-\bar{\nu}
We present a measurement of the Cabibbo-Kobayashi-Maskawa (CKM) matrix
element |Vcb| using a 10.2 fb^{-1} data sample recorded at the \Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric e^+e^- storage ring.
By extrapolating the differential decay width of the \bar{B}^0 -->
D^{*+}e^-\bar{\nu} decay to the kinematic limit at which the D^{*+} is at rest
with respect to the \bar{B}^0, we extract the product of |Vcb| with the
normalization of the decay form factor F(1), |Vcb |F(1)=
(3.54+/-0.19+/-0.18)x10^{-2}, where the first error is statistical and the
second is systematic. A value of |Vcb| = (3.88+/-0.21+/-0.20+/-0.19)x10^{-2} is
obtained using a theoretical calculation of F(1), where the third error is due
to the theoretical uncertainty in the value of F(1). The branching fraction
B(\bar{B}^0 --> D^{*+}e^-\bar{\nu}) is measured to be
(4.59+/-0.23+/-0.40)x10^{-2}.Comment: 20 pages, 6 figures, elsart.cls, submitted to PL
Measurement of the inclusive semileptonic branching fraction of B mesons and |Vcb|
We present a measurement of the electron spectrum from inclusive semileptonic
{\it B} decay, using 5.1 fb of data collected with the
Belle detector. A high-momentum lepton tag was used to separate the
semileptonic {\it B} decay electrons from secondary decay electrons. We
obtained the branching fraction, , with minimal model dependence.
From this measurement, we derive a value for the Cabibbo-Kobayashi-Maskawa
matrix element .Comment: 16 pages, 3 figures, 3 table
Search for R-parity Violating Decays of Supersymmetric Particles in e+e- Collisions at LEP
A search, in e^+e^- collisions, for chargino, neutralino, scalar lepton and
scalar quark pair-production is performed, without assuming R-parity
conservation in decays, in the case that only one of the coupling constants
lambda_ijk or lambda''_ijk is non-negligible. No signal is found in data up to
a centre-of-mass energy of 208GeV. Limits on the production cross sections and
on the masses of supersymmetric particles are derived
Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays
Average charged multiplicities have been measured separately in , and
light quark () events from decays measured in the SLD experiment.
Impact parameters of charged tracks were used to select enriched samples of
and light quark events, and reconstructed charmed mesons were used to select
quark events. We measured the charged multiplicities:
,
, from
which we derived the differences between the total average charged
multiplicities of or quark events and light quark events: and . We compared
these measurements with those at lower center-of-mass energies and with
perturbative QCD predictions. These combined results are in agreement with the
QCD expectations and disfavor the hypothesis of flavor-independent
fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters
Measurement of Bose-Einstein Correlations in e+e- -> W+W- at root(s)=189GeV
We investigate Bose-Einstein correlations (BEC) in W-pair production at
root(s)=189GeV using the L3 detector at LEP. We observe BEC between particles
from a single W decay in good agreement with those from a light-quark Z decay
sample. We investigate their possible existence between particles coming from
different W's. No evidence for such inter-W BEC is found
Study of the e+e- -> Ze+e- process at LEP
The cross section of the process e+e- -> Ze+e is measured with 0.7fb^-1 of
data collected with the L3 detector at LEP. Decays of the Z boson into quarks
and muons are considered at centre-of-mass energies ranging from 183GeV up to
209GeV. The measurements are found to agree with Standard Model predictions,
achieving a precision of about 10% for the hadronic channel
Search for Heavy Neutral and Charged Leptons in e+ e- Annihilation at LEP
A search for exotic unstable neutral and charged heavy leptons as well as for
stable charged heavy leptons is performed with the L3 detector at LEP.
Sequential, vector and mirror natures of heavy leptons are considered. No
evidence for their existence is found and lower limits on their masses are set
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