1,120 research outputs found
Determination of the moments of the proton charge density
A global analysis of proton electric form factor experimental data from
Rosenbluth separation and low squared four-momentum transfer experiments is
discussed for the evaluation of the spatial moments of the proton charge
density based on the recently published integral method \cite{Hob20}. Specific
attention is paid to the evaluation of the systematic errors of the method,
particularly the sensitivity to the choice of the mathematical expression of
the form factor fitting function. Within this comprehensive analysis of proton
electric form factor data, the moments of the proton charge density are
determined for integer order moments, particularly: =0.682(02)(11)~fm, =0.797(10)(58)~fm, and =1.02(05)(31)~fm. This analysis leads to the
proton charge radius 0.8459(12)(76)~fm once relativistic
effects are taken into account.Comment: 10 pages, 3 figure
Integration of Long-Read Whole Genome Sequencing in Graduate Curriculum of Diagnostic Genetics and Genomics
https://openworks.mdanderson.org/edwk22/1008/thumbnail.jp
Saturated phase densities of (CO2 + H2O) at temperatures from (293 to 450) K and pressures up to 64 MPa
An apparatus consisting of an equilibrium cell connected to two vibrating tube densimeters and two syringe pumps was used to measure the saturated phase densities of (CO2 + H2O) at temperatures from (293 to 450) K and pressures up to 64 MPa, with estimated average standard uncertainties of 1.5 kg · m−3 for the CO2-rich phase and 1.0 kg · m−3 for the aqueous phase. The densimeters were housed in the same thermostat as the equilibrium cell and were calibrated in situ using pure water, CO2 and helium. Following mixing, samples of each saturated phase were displaced sequentially at constant pressure from the equilibrium cell into the vibrating tube densimeters connected to the top (CO2-rich phase) and bottom (aqueous phase) of the cell. The aqueous phase densities are predicted to within 3 kg · m−3 using empirical models for the phase compositions and partial molar volumes of each component. However, a recently developed multi-parameter equation of state (EOS) for this binary mixture, Gernert and Span [32], was found to under predict the measured aqueous phase density by up to 13 kg · m−3. The density of the CO2-rich phase was always within about 8 kg · m−3 of the density for pure CO2 at the same pressure and temperature; the differences were most positive near the critical density, and became negative at temperatures above about 373 K and pressures below about 10 MPa. For this phase, the multi-parameter EOS of Gernert and Span describes the measured densities to within 5 kg · m−3, whereas the computationally-efficient cubic EOS model of Spycher and Pruess (2010), commonly used in simulations of subsurface CO2 sequestration, deviates from the experimental data by a maximum of about 8 kg · m−3
The potential of open-access data for flood estimations: uncovering inundation hotspots in Ho Chi Minh City, Vietnam, through a normalized flood severity index
Hydro-numerical models are increasingly important to
determine the adequacy and evaluate the effectiveness of potential flood
protection measures. However, a significant obstacle in setting up
hydro-numerical and associated flood damage models is the tedious and
oftentimes prohibitively costly process of acquiring reliable input data,
which particularly applies to coastal megacities in developing countries and
emerging economies. To help alleviate this problem, this paper explores the
usability and reliability of flood models built on open-access data in
regions where highly resolved (geo)data are either unavailable or difficult
to access yet where knowledge about elements at risk is crucial for
mitigation planning. The example of Ho Chi Minh City, Vietnam, is taken to
describe a comprehensive but generic methodology for obtaining, processing
and applying the required open-access data. The overarching goal of this
study is to produce preliminary flood hazard maps that provide first insights
into potential flooding hotspots demanding closer attention in subsequent,
more detailed risk analyses. As a key novelty, a normalized flood severity
index (INFS), which combines flood depth and duration, is proposed to
deliver key information in a preliminary flood hazard assessment. This index
serves as an indicator that further narrows down the focus to areas where
flood hazard is significant. Our approach is validated by a comparison with
more than 300 flood samples locally observed during three heavy-rain events
in 2010 and 2012 which correspond to INFS-based inundation hotspots in
over 73 % of all cases. These findings corroborate the high potential of
open-access data in hydro-numerical modeling and the robustness of the newly
introduced flood severity index, which may significantly enhance the
interpretation and trustworthiness of risk assessments in the future. The
proposed approach and developed indicators are generic and may be replicated
and adopted in other coastal megacities around the globe.</p
Plants Attract Parasitic Wasps to Defend Themselves against Insect Pests by Releasing Hexenol
Plant volatiles play an important role in defending plants against insect attacks by attracting their natural enemies. For example, green leaf volatiles (GLVs) and terpenoids emitted from herbivore-damaged plants were found to be important in the host location of parasitic wasps. However, evidence of the functional roles and mechanisms of these semio-chemicals from a system of multiple plants in prey location by the parasitoid is limited. Little is known about the potential evolutionary trends between herbivore-induced host plant volatiles and the host location of their parasitoids.. Specifically, we found that volatile profiles from healthy plants revealed a partly phylogenetic signal, while the inducible compounds of the infested-plants did not result from the fact that the induced plant volatiles dominate most of the volatile blends of the host and non-host plants of the leafminer pests. We further show that the parasitoids are capable of distinguishing the damaged host plant from the non-host plant of the leafminers.Our results suggest that, as the most passive scenario of plant involvement, leafminers and mechanical damages evoke similar semio-chemicals. Using ubiquitous compounds, such as hexenol, for host location by general parasitoids could be an adaptation of the most conservative evolution of tritrophic interaction. Although for this, other compounds may be used to improve the precision of the host location by the parasitoids
Observation of two new baryon resonances
Two structures are observed close to the kinematic threshold in the mass spectrum in a sample of proton-proton collision data, corresponding
to an integrated luminosity of 3.0 fb recorded by the LHCb experiment.
In the quark model, two baryonic resonances with quark content are
expected in this mass region: the spin-parity and
states, denoted and .
Interpreting the structures as these resonances, we measure the mass
differences and the width of the heavier state to be
MeV,
MeV,
MeV, where the first and second
uncertainties are statistical and systematic, respectively. The width of the
lighter state is consistent with zero, and we place an upper limit of
MeV at 95% confidence level. Relative
production rates of these states are also reported.Comment: 17 pages, 2 figure
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
Measurement of the mass and lifetime of the baryon
A proton-proton collision data sample, corresponding to an integrated
luminosity of 3 fb collected by LHCb at and 8 TeV, is used
to reconstruct , decays. Using the , decay mode for calibration, the lifetime ratio and absolute
lifetime of the baryon are measured to be \begin{align*}
\frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\
\tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the
uncertainties are statistical, systematic and from the calibration mode (for
only). A measurement is also made of the mass difference,
, and the corresponding mass, which
yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm
MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2.
\end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm
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