888 research outputs found
Variations in water use by a mature mangrove of Avicennia germinans, French Guiana
In the tropical intertidal zones, little is known on water uptake by mangroves. Transpiration rates are generally measured at leaf level, but few studies exist on water use at tree or stand levels. The objective of this study was to measure sap flow in trees of different sizes to appreciate the range of variation in water use that may exist in a site dominated by 80% mature Avicennia germinans. The results showed that from the dry to the wet season the mean water use increased from 3.2 to 5.3 dm3 d−1 in small trees (DBH ∼ 13 cm), from 11.5 to 30.8 dm3 d−1 in medium trees (∼24 cm) and from 40.8 to 64.1 dm3 d−1 in large ones (∼45 cm). Sapwood remained active up to a depth of 8 cm with radial variations within the stem. Weak correlations were obtained with VPD and net radiation. This study confirmed that transpiration was larger under low levels of salinity. Water use at stand level (∼1900 living stems ha−1) was estimated to be in the range of 5.8 to 11.8 m3 ha−1 d−1 according to the season
A Bayesian technique for improving the sensitivity of the atmospheric neutrino L/E analysis
This paper outlines a method for improving the precision of atmospheric
neutrino oscillation measurements. One experimental signature for these
oscillations is an observed deficit in the rate of charged-current
interactions with an oscillatory dependence on , where
is the neutrino propagation distance, and is the neutrino
energy. For contained-vertex atmospheric neutrino interactions, the
resolution varies significantly from event to event. The
precision of the oscillation measurement can be improved by incorporating
information on resolution into the oscillation analysis. In
the analysis presented here, a Bayesian technique is used to estimate the
resolution of observed atmospheric neutrinos on an
event-by-event basis. By separating the events into bins of
resolution in the oscillation analysis, a significant improvement in
oscillation sensitivity can be achieved.Comment: 12 pages, 7 figures, submitted to Nucl. Instrum. Methods A,
accompanies arXiv:1208.2915 [hep-ex
Prospects for the Measurement of the Higgs Yukawa Couplings to b and c quarks, and muons at CLIC
The investigation of the properties of the Higgs boson, especially a test of
the predicted linear dependence of the branching ratios on the mass of the
final state is going to be an integral part of the physics program at colliders
at the energy frontier for the foreseeable future. The large Higgs boson
production cross section at a 3TeV CLIC machine allows for a precision
measurement of the Higgs branching ratios. The cross section times branching
ratio of the decays H->bb, H->cc and H->{\mu}{\mu} of a Standard Model Higgs
boson with a mass of 120 GeV can be measured with a statistical uncertainty of
0.23%, 3.1% and 15%, respectively, assuming an integrated luminosity of 2 ab-1.Comment: 6 pages, 4 figure
Theory of periodic swarming of bacteria: application to Proteus mirabilis
The periodic swarming of bacteria is one of the simplest examples for pattern
formation produced by the self-organized collective behavior of a large number
of organisms. In the spectacular colonies of Proteus mirabilis (the most common
species exhibiting this type of growth) a series of concentric rings are
developed as the bacteria multiply and swarm following a scenario periodically
repeating itself. We have developed a theoretical description for this process
in order to get a deeper insight into some of the typical processes governing
the phenomena in systems of many interacting living units. All of our
theoretical results are in excellent quantitative agreement with the complete
set of available observations.Comment: 11 pages, 8 figure
Carbon burial on river-dominated continental shelves: Impact of historical changes in sediment loading adjacent to the Mississippi River
Seabed cores collected on the continental shelf adjacent to the Mississippi River show a direct temporal correlation between decreases in mass accumulation rate (factor of 2-3) and suspended sediment loads in the river. This mid 20th century decline is not apparent shelf-wide due to sediment focusing and biological seabed mixing. Total organic carbon diagenetic loss rate across this sediment age interval is relatively uninterrupted when coffected for the non-steady state mass flux. This suggests that organic carbon burial rates in oxic bottom water settings on river-dominated continental margins are directly proportional to lithogenic flux. Variations in OM remineralization rates due to changes in the composition (marine vs. terrestrial) of the particulate OM flux at the sediment surface are a second-order effect that cannot be distinguished in the bulk carbon sediment record at these oxic sites; although they may significantly alter the OM degradation-induced CO2 flux to the overlying water column
Study of Bc --> J/psi pi, etac pi decays with perturbative QCD approach
The Bc --> J/psi pi, etac pi decays are studied with the perturbative QCD
approach. It is found that form factors and branching ratios are sensitive to
the parameters w, v, f_J/psi and f_etac, where w and v are the parameters of
the charmonium wave functions for Coulomb potential and harmonic oscillator
potential, respectively, f_J/psi and f_etac are the decay constants of the
J/psi and etac mesons, respectively. The large branching ratios and the clear
signals of the final states make the Bc --> J/psi pi, etac pi decays to be the
prospective channels for measurements at the hadron collidersComment: 21 pages, revtex
Sex and age differences in "theory of mind" across 57 countries using the English version of the "Reading the Mind in the Eyes" Test.
The "Reading the Mind in the Eyes" Test (Eyes Test) is a widely used assessment of "theory of mind." The NIMH Research Domain Criteria recommends it as one of two tests for "understanding mental states." Previous studies have demonstrated an on-average female advantage on the Eyes Test. However, it is unknown whether this female advantage exists across the lifespan and across a large number of countries. Thus, we tested sex and age differences using the English version of the Eyes Test in adolescents and adults across 57 countries. We also tested for associations with sociodemographic and cognitive/personality factors. We leveraged one discovery dataset (N = 305,726) and three validation datasets (Ns = 642; 5,284; and 1,087). The results show that: i) there is a replicable on-average female advantage in performance on the Eyes Test; ii) performance increases through adolescence and shallowly declines across adulthood; iii) the on-average female advantage is evident across the lifespan; iv) there is a significant on-average female advantage in 36 out of 57 countries; v) there is a significant on-average female advantage on translated (non-English) versions of the Eyes Test in 12 out of 16 countries, as confirmed by a systematic review; vi) D-scores, or empathizing-systemizing, predict Eyes Test performance above and beyond sex differences; and vii) the female advantage is negatively linked to "prosperity" and "autonomy," and positively linked to "collectivism," as confirmed by exploratory country-level analyses. We conclude that the on-average female advantage on the Eyes Test is observed across ages and most countries
Ruling out four-neutrino oscillation interpretations of the LSND anomaly?
Prompted by recent solar and atmospheric data, we re-analyze the
four-neutrino description of current global neutrino oscillation data,
including the LSND evidence for oscillations. The higher degree of rejection
for non-active solar and atmospheric oscillation solutions implied by the SNO
neutral current result as well as by the latest 1489-day Super-K atmospheric
neutrino data allows us to rule out (2+2) oscillation schemes proposed to
reconcile LSND with the rest of current neutrino oscillation data. Using an
improved goodness of fit (gof) method especially sensitive to the combination
of data sets we obtain a gof of only 1.6 times 10^{-6} for (2+2) schemes.
Further, we re-evaluate the status of (3+1) oscillations using two different
analyses of the LSND data sample. We find that also (3+1) schemes are strongly
disfavoured by the data. Depending on the LSND analysis we obtain a gof of 5.6
times 10^{-3} or 7.6 times 10^{-5}. This leads to the conclusion that all
four-neutrino descriptions of the LSND anomaly, both in (2+2) as well as (3+1)
realizations, are highly disfavoured. Our analysis brings the LSND hint to a
more puzzling status.Comment: 21 pages, 7 figure
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