1,090 research outputs found
Evaluation of Infiltration in Furrow Irrigation Part 1: Recession Flow
Recession flow in a large field can be significant from the point of view of water-use efficiency. This is particularly
important in the case where the furrow field is long, thus the receding flow can contribute to the irrigation of crops.
Indeed, recession flow is very significant in the surge method of furrow irrigation. In the continuous mode of
operation in very long furrows the amount of recession flow can be significant. Herein is presented the mathematical
modelling of the recession flow. The analytical procedure is based on the kinematic wave approach used for the
simulation of the advance-flow trajectory for furrows. This resulting recession simulation was found to be very useful
for the evaluation of the basic infiltration rate in a furrow
Global Entanglement for Multipartite Quantum States
Based on the residual entanglement [9] (Phys. Rev. A \textbf{71}, 044301
(2005)), we present the global entanglement for a multipartite quantum state.
The measure is shown to be also obtained by the bipartite partitions of the
multipartite state. The distinct characteristic of the global entanglement is
that it consists of the sum of different entanglement contributions. The
measure can provide sufficient and necessary condition of fully separability
for pure states and be conveniently extended to mixed states by minimizing the
convex hull. To test the sufficiency of the measure for mixed states, we
evaluate the global entanglement of bound entangled states. The properties of
the measure discussed finally show the global entanglement is an entanglement
monotone.Comment: 6 page
Evaluation of Infiltration in Furrow Irrigation Part 2 : Basic Infiltration Rate
Part 1 of this title was the simulation of the recession flow in a furrow. This part
uses the recession simulation further to establish the basic infiltration rate in
a furrow and, therefore, the infiltration characteristics in a furrow. Determining
infiltration in a furrow is complicated by the dynamic flow nature of irrigation
water, as well as the geometric shape of the channel, among other factors. The
evaluation of this infiltration in furrows is important in order to evaluate the
water use in such irrigation systems. The use of the Kostiakov equation in its
extended form has been suggested for the determination of infiltration characteristics
in a furrow. This equation, however, depends on the evaluation of
the long-term basic infiltration rate, which can be determined practically by a
long-term tedious inflow/outflow hydrograph of the irrigation event. An analytical
method based on the kinematic wave theory and recession flow data is
proposed here to evaluate the long-term basic infiltration rate pertinent to the
correct evaluation of the infiltration flow characteristics in a furrow
A computed-based model for the alkali concentrations in pore solution of hydrating Portland cement paste
A computed-based model for the alkali concentrations in pore solution of hydrating Portland cement paste is proposed. Experimental data reported in different literatures with thirteen different recipes are analyzed. A 3-D computer-based cement hydration model CEMHYD3D is used to simulate the hydration of these pastes. The models predictions are used as inputs for the alkali partition theory, which is used to derive the alkali binding capacity of C-S-H in hydrating Portland cement paste. A linear relation between the amount of bound-alkali Na+ in C-S-H and its concentration in the pore solution is found, whilst a non-linear relation should be employed for the amount of bound-alkali K+ in C-S-H. New methods for predicting the alkali concentrations in the pore solution of hydrating Portland cement pastes are proposed based on the computer model CEMHYD3D, which is also validated with experimental results
Concurrence of superposition
The bounds on concurrence of the superposition state in terms of those of the
states being superposed are studied in this paper. The bounds on concurrence
are quite different from those on the entanglement measure based on von Neumann
entropy (Phys. Rev. Lett. 97, 100502 (2006)). In particular, a nonzero lower
bound can be provided if the states being superposed are properly constrained.Comment: 4 page
Lattice Boltzmann Approach to High-Speed Compressible Flows
We present an improved lattice Boltzmann model for high-speed compressible
flows. The model is composed of a discrete-velocity model by Kataoka and
Tsutahara [Phys. Rev. E \textbf{69}, 056702 (2004)] and an appropriate
finite-difference scheme combined with an additional dissipation term. With the
dissipation term parameters in the model can be flexibly chosen so that the von
Neumann stability condition is satisfied. The influence of the various model
parameters on the numerical stability is analyzed and some reference values of
parameter are suggested. The new scheme works for both subsonic and supersonic
flows with a Mach number up to 30 (or higher), which is validated by well-known
benchmark tests. Simulations on Riemann problems with very high ratios
() of pressure and density also show good accuracy and stability.
Successful recovering of regular and double Mach shock reflections shows the
potential application of the lattice Boltzmann model to fluid systems where
non-equilibrium processes are intrinsic. The new scheme for stability can be
easily extended to other lattice Boltzmann models.Comment: Figs.11 and 12 in JPEG format. Int. J. Mod. Phys. C (to appear
Differences in Mode of Action of Cochinchinenin A and B on Tetrodotoxin-Resistant Sodium Channels
Purpose: To explore the mechanism of antagonistic interaction between cochinchinenin A and B in modulating tetrodotoxin-resistant (TTR-X) sodium currents.Methods: The time variation of the effects induced by cochinchinenin A and B on the TTX-R sodium currents in dorsal root ganglion (DRG) neurons of rats were observed using whole-cell patch clamp technique. Based on pharmacological fundamental theory, the modes of action of cochinchinenin A and B on TTX-R channels were distinguished.Results: The scatter diagram which reflected the time variation of inhibition effect on TTX-R sodium currents induced by cochinchinenin A fitted well with occupancy theory equation (goodness of fit test, p > 0.05), while that of cochinchinenin B fitted well with rate theory equation (p > 0.05). The rate constants for combination and dissociation between cochinchinenin A and TTX-R sodium channel were (198.7 ± 39.9) x 10-3 and (41.1 ± 6.2) x 10-3 respectively; while corresponding values for combination andassociation between cochinchinenin B and TTX-R sodium channel were (99.9 ± 16.8) x 10-3 and (5.3 ± 0.4) x 10-3 respectively.Conclusion: The main cause of the antagonistic interaction between cochinchinenin A and B may be attributed to the different modes of their action on TTX-R sodium channels.Keywords: Cochinchinenin, Tetrodotoxin-resistant sodium channel, Antagonistic interaction, Occupancy theory, Rate theor
Histopathology and selective biomarker expression in human meibomian glands
BACKGROUND/AIMS: Meibomian gland dysfunction (MGD) is the most common form of evaporative dry eye disease, but its pathogenesis is poorly understood. This study examined the histopathological features of meibomian gland (MG) tissue from cadaver donors to identify potential pathogenic processes that underlie MGD in humans.
METHODS: Histological analyses was performed on the MGs in the tarsal plates dissected from four cadaver donors, two young and two old adults, including a 36-year-old female (36F) and three males aged 30, 63 and 64 years (30M, 63M and 64M).
RESULTS: The MGs of 36F displayed normal anatomy and structure, whereas the MGs of 30M showed severe ductal obstruction with mild distortion. The obstruction was caused by increased cytokeratin levels in association with hyperproliferation, but not hyperkeratinisation. In two older males, moderate to severe MG atrophy was noted. Cell proliferation was significantly reduced in the MG acini of the two older donors as measured by Ki67 labelling index (6.0%±3.4% and 7.9%±2.8% in 63M and 64M, respectively) when compared with that of the two younger donors (23.2%±5.5% and 16.9%±4.8% in 30M and 36F, respectively) (p\u3c0.001). The expression patterns of meibocyte differentiation biomarkers were similar in the older and younger donors.
CONCLUSION: Our histopathological study, based on a small sample size, suggests potentially distinct pathogenic mechanisms in MGD. In the young male adult, hyperproliferation and aberrant differentiation of the central ductal epithelia may lead to the obstruction by overproduced cytokeratins. In contrast, in older adults, decreased cell proliferation in acinar basal epithelia could be a contributing factor leading to MG glandular atrophy
Neutrino mass and low-temperature calorimetry
We describe how the problem of measuring the neutrino mass led us to the development of low-temperature calorimetry. The search for a "17-keV neutrino" concluded with a negative result, but a wide range of applications are now carried on by us and by other groups in the fields of x-ray astronomy, recoil measurements of dark matter particles, high precision particle spectrometry, specific heat determinations, neutron detection, rare decay studies. The masses of the bolometers (calorimeters) extend from 1 mg to 1 Kg, nearly as large as for quantum detectors. By lowering the temperature into the 10-20 mK range, calorimetry is on the way to surpass substantially the high precision of particle metrology obtainable with the quantum detectors. Calorimeter developments and perspectives are discussed
Andromeda's Parachute: A Bright Quadruply Lensed Quasar at z=2.377
We present Keck Cosmic Web Imager spectroscopy of the four putative images of
the lensed quasar candidate J014709+463037 recently discovered by Berghea et
al. (2017). The data verify the source as a quadruply lensed, broad
absorption-line quasar having z_S = 2.377 +/- 0.007. We detect intervening
absorption in the FeII 2586, 2600, MgII 2796, 2803, and/or CIV 1548, 1550
transitions in eight foreground systems, three of which have redshifts
consistent with the photometric-redshift estimate reported for the lensing
galaxy (z_L ~ 0.57). By virtue of their positions on the sky, the source images
probe these absorbers over transverse physical scales of ~0.3-21 kpc,
permitting assessment of the variation in metal-line equivalent width W_r as a
function of sight-line separation. We measure differences in W_r,2796 of <40%
across all sight-line pairs subtending 7-21 kpc, suggestive of a high degree of
spatial coherence for MgII-absorbing material. W_r,2600 is observed to vary by
>50% over the same scales across the majority of sight-line pairs, while CIV
absorption exhibits a wide range in W_r,1548 differences of ~5-80% within
transverse distances less than ~3 kpc. J014709+463037 is one of only a handful
of z > 2 quadruply lensed systems for which all four source images are very
bright (r = 15.4-17.7 mag) and are easily separated in ground-based seeing
conditions. As such, it is an ideal candidate for higher-resolution
spectroscopy probing the spatial variation in the kinematic structure and
physical state of intervening absorbers.Comment: Submitted to ApJL. 9 pages, 3 figures. Uses aastex61 forma
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