1,271 research outputs found
P051: Factors responsible for methicillin-resistant Staphylococcus aureus outbreak in the neonatal intensive care unit
Produção de serapilheira em reflorestamento com paricá (Schyzolobium parahyba var. amazonicum) em áreas degradadas em Aurora do Pará, Pará.
Resumo: 509
In situ observation of atmospheric oxygen and carbon dioxide in the North Pacific using a cargo ship
Atmospheric oxygen (O2) and carbon dioxide (CO2) variations in the
North Pacific were measured aboard a cargo ship, the New Century 2
(NC2), while it cruised between Japan and the United States between
December 2015 and November 2016. A fuel cell analyzer and a nondispersive
infrared analyzer were used for the measurement of O2 and
CO2, respectively. To achieve parts-per-million precision for the
O2 measurements, we precisely controlled the flow rates of the
sample and reference air introduced into the analyzers and the outlet
pressure. A relatively low airflow rate (10 cm3 min−1) was
adopted to reduce the consumption rate of the reference gases. In the
laboratory, the system achieved measurement precisions of 3.8 per meg for
δ(O2 ∕ N2), which is commonly used to express
atmospheric O2 variation, and 0.1 ppm for the CO2 mole
fraction. After the in situ observation started aboard NC2, we found that
the ship's motion caused false wavy variations in the O2 signal
with an amplitude of more than several tens of ppm and a period of about
20 s. Although we have not resolved the problem at this stage, hourly
averaging considerably suppressed the variation associated with ship motion.
Comparison between the in situ observation and flask sampling of air
samples aboard NC2 showed that the averaged differences (in situ–flask)
and the standard deviations (±1σ) are −2.8 ± 9.4 per meg
for δ(O2 ∕ N2) and −0.02 ± 0.33 ppm
for the CO2 mole fraction. We compared 1 year of in situ data for
atmospheric potential oxygen (APO; O2 +1.1 × CO2)
obtained from the broad middle-latitude region
(140° E–130° W, 29° N–45° N) with
previous flask sampling data from the North Pacific. This comparison showed
that longitudinal differences in the seasonal amplitude of APO, ranging from
51 to 73 per meg, were smaller than the latitudinal differences.</p
Observation of Double cc bar Production in e+ e- Annihilation at sqrt{s} ~ 10.6 GeV
We report the observation of prompt J/psi via double ccbar production from
the e+e- continuum. In this process one ccbar pair fragments into a J/psi meson
while the remaining pair either produces a bound charmonium state or fragments
into open charm. Both cases have been observed: the first by studying the mass
spectrum of the system recoiling against the J/psi, and the second by
reconstructing the J/psi together with a charmed meson. We find cross-sections
of \sigma(e+ e- -> J/psi eta_c (gamma)) * BR (eta_c -> >=4 charged) = 0.033
(+0.007 -0.006)(stat) \pm 0.009(syst)pb and \sigma(e+ e- -> J/psi D*+ X) = 0.53
(+0.19 -0.15)(stat) \pm 0.14(syst) pb, and infer \sigma(e+ e- -> J/psi c cbar)
/ \sigma(e+ e- -> J/psi X) = 0.59 (+0.15 -0.13)(stat) \pm 0.12(syst). These
results are obtained from a 46.2/fb data sample collected near the Upsilon(4S)
resonance, with the Belle detector at the KEKB asymmetric energy e+ e-
collider.Comment: 7 pages, 2 figures, to be submitted to Physical Review Letter
Observation of Cabibbo-suppressed and W-exchange Lambda_c^+ baryon decays
We present measurements of the Cabibbo-suppressed decays Lambda_c^+ -->
Lambda0 K+ and Lambda_c^+ --> Sigma0 K+ (both first observations), Lambda_c^+
--> Sigma+ K+ pi- (seen with large statistics for the first time), Lambda_c^+
--> p K+ K- and Lambda_c^+ --> p phi (measured with improved accuracy).
Improved branching ratio measurements for the decays Lambda_c^+ --> Sigma+ K+
K- and Lambda_c^+ --> Sigma+ phi, which are attributed to W-exchange diagrams,
are shown. We also present the first evidence for Lambda_c^+ --> Xi(1690)^0 K+
and set an upper limit on the non-resonant decay Lambda_c^+ --> Sigma+ K+ K-.
This analysis was performed using 32.6 fb^{-1} of data collected by the Belle
detector at the asymmetric e+ e- collider KEKB.Comment: Submitted to Phys. Lett. B. v2: A small correction to the Authorlist
was made. An earlier version of this analysis was released as
BELLE-CONF-0130, hep-ex/010800
Evidence for Direct CP Violation in B0 -> K+- pi-+ Decays
We report evidence for direct CP violation in the decay B0 -> K+-pi-+ with
253/fb of data collected with the Belle detector at the KEKB e+e- collider.
Using 275 million B B_bar pairs we observe a B -> K+-pi-+ signal with 2140+-53
events. The measured CP violating asymmetry is Acp(K+-pi-+) = -0.101+-0.025
(stat)+-0.005 (syst), corresponding to a significance of 3.9 sigma including
systematics. We also search for CP violation in the decays B+- -> K+-pi0 and
B+- -> pi+-pi0. The measured CP violating asymmetries are Acp(K+-pi0) =
0.04+-0.05(stat)+-0.02(syst) and Acp(pi+-pi0) = -0.02+-0.10(stat)+-0.01(syst),
corresponding to the intervals -0.05 < Acp(K+-pi0) < 0.13 and
-0.18<Acp(pi+-pi0)<0.14 at 90% confidence level.Comment: 9 pages, 3 figures. submitted to Physical Review Letter
Observation of B0bar --> D(*)0 p pbar
The B meson decay modes B --> D p pbar and B --> D* p pbar have been studied
using 29.4 fb^{-1} of data collected with the Belle detector at KEKB. The B0bar
--> D0 p pbar and B0bar --> D*0 p pbar decays have been observed for the first
time with branching fractions Br(B0bar --> D0 p pbar) =(1.18\pm 0.15\pm 0.16)
10^{-4} and Br(B0bar --> D*0 p pbar) =(1.20^{+0.33}_{-0.29}\pm 0.21) 10^{-4}.
No signal has been found for the B+ --> D+ p pbar and B+ --> D*+ p pbar decay
modes, and the corresponding upper limits at 90% C.L. are presented.Comment: 6 pages, 3 figures, submited to Phys. Rev. Let
A Measurement of Lifetime Difference in Meson Decays
We report a measurement of the - mixing parameter
using 23.4 fb of data collected near the (4S) resonance with
the Belle detector at KEKB. is measured from the lifetime difference
of mesons decaying into the state and the CP even eigenstate
. We find , where
the first error is statistical and the second systematic, corresponding to a
95% confidence interval .Comment: 10 pages, 3 figure
Observation of Large CP Violation in the Neutral B Meson System
We present a measurement of the Standard Model CP violation parameter sin
2phi_1 based on a 29.1 fb^{-1} data sample collected at the Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.
One neutral B meson is fully reconstructed as a J/psi Ks, psi(2S) Ks, chi_c1
Ks, eta_c Ks, J/psi K_L or J/psi K^{*0} decay and the flavor of the
accompanying B meson is identified from its decay products. From the asymmetry
in the distribution of the time intervals between the two B meson decay points,
we determine sin 2phi_1 = 0.99 +- 0.14(stat) +- 0.06(syst). We conclude that we
have observed CP violation in the neutral B meson system.Comment: 4 figures, to appear in Phys. Rev. Letter
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