3,426 research outputs found
Determination of saturation bands set using LAB color system
В статье рассматривается определение насыщенности набора с помощью измерения в программе Adobe Photoshop уровня яркости L черно-белого размытого изображения полосы в цветовой системе LAB. Приводятся методика и результаты измерения насыщенности при оформлении полосы шрифтами с засечками и без засечек, а также рядом кеглей. Установлен волнообразный характер изменения насыщенности полосы при увеличении кегля от 6 до 72 пунктов.The article deals with the definition of saturation set with the help of measurements in the pro-gram Adobe Photoshop brightness level L Black-and-white blur image strip in the color system of LAB. The technique and results of measuring the saturation when you make a band serif and sans serif, and a number of pins. Established in waves change the saturation of the band at a size increase from 6 to 72 points
Modeling the Enceladus plume--plasma interaction
We investigate the chemical interaction between Saturn's corotating plasma
and Enceladus' volcanic plumes. We evolve plasma as it passes through a
prescribed H2O plume using a physical chemistry model adapted for water-group
reactions. The flow field is assumed to be that of a plasma around an
electrically-conducting obstacle centered on Enceladus and aligned with
Saturn's magnetic field, consistent with Cassini magnetometer data. We explore
the effects on the physical chemistry due to: (1) a small population of hot
electrons; (2) a plasma flow decelerated in response to the pickup of fresh
ions; (3) the source rate of neutral H2O. The model confirms that charge
exchange dominates the local chemistry and that H3O+ dominates the water-group
composition downstream of the Enceladus plumes. We also find that the amount of
fresh pickup ions depends heavily on both the neutral source strength and on
the presence of a persistent population of hot electrons.Comment: 10 pages, 1 table, 2 figure
Ureteroscopic lithotripsy for ureteral stones in children using holmium: yag laser energy: results of a multicentric survey
BACKGROUND:
Holmium:YAG (Ho:YAG) laser lithotripsy has broadened the indications for ureteroscopic stone managements in adults, but few evidence are currently available in the pediatric population.
OBJECTIVE:
This article aimed to assess the outcome of Ho:YAG laser lithotripsy during retrograde ureteroscopic management of ureteral stones in different locations in children.
STUDY DESIGN:
The medical records of 149 patients (71 boys and 78 girls; median age 9.2 years) treated with Ho:YAG laser ureteroscopic lithotripsy in five international pediatric urology units over the last 5 years were retrospectively reviewed. Exclusion criteria included patients with renal calculi and/or with a history of ipsilateral stricture, renal failure, active urinary tract infection, or coagulation disorder.
RESULTS:
Stones were treated with dusting technique in all cases. The median stone size was 10.3 mm (range 5-17). Stones were located in the distal ureter in 77 cases (51.7%), in the middle ureter in 23 cases (15.4%), and in the proximal ureter in 49 cases (32.9%). The median operative time was 29.8 min (range 20-95). Intra-operative complications included five bleedings (3.3%) and seven stone retropulsions (4.7%). Overall stone-free rate was 97.3%. Overall postoperative complications rate was 4.0% and included two cases of stent migration (1.3%) (Clavien II) and four residual stone fragments (2.7%) that were successfully treated using the same technique (Clavien IIIb). On multivariate analysis, re-operation rate was significantly dependent on the proximal stone location and presence of residual fragments >2 mm (P = 0.001).
DISCUSSION:
This study is one of the largest pediatric series among those published until now. The study series reported a shorter operative time, a higher success rate, and a lower postoperative complications rate compared with previous series. A limitation of this study is that stone-free rates may be somewhat inaccurate using ultrasonography and plain X-ray compared with computed tomography (CT); the study's 97.3% success rate may be overestimated because no CT scan was done postoperatively to check the stone-free rate. Other limitations of this article include its retrospective nature, the multi-institutional participation, and the heterogeneous patient collective.
CONCLUSION:
The Ho:YAG laser ureteroscopic lithotripsy seems to be an excellent first-line treatment for children with ureteral stones, independently from primary location and size. However, patients with proximal ureteral stones and residual fragments >2 mm reported a higher risk to require a secondary procedure to become stone-free. Combination of techniques as well as appropriate endourologic tools are key points for the success of the procedure regardless of stones' size and location
A possible nature of breathing plasmas
A model for "breathing" plasmas observed in the large helical device [Y. Takeiri , Plasma Phys. Controlled Fusion 42, 147 (2000)] is proposed. It takes into account the synergism of radiation losses from both low-Z (carbon, oxygen) and high-Z (iron) impurities in the plasma power balance. (C) 2000 American Institute of Physics. [S1070- 664X(00)01411-7]
Design and construction of new central and forward muon counters for CDF II
New scintillation counters have been designed and constructed for the CDF
upgrade in order to complete the muon coverage of the central CDF detector, and
to extend this coverage to larger pseudorapidity. A novel light collection
technique using wavelength shifting fibers, together with high quality
polystyrene-based scintillator resulted in compact counters with good and
stable light collection efficiency over lengths extending up to 320 cm. Their
design and construction is described and results of their initial performance
are reported.Comment: 20 pages, 15 figure
Theory of temperature dependence of the Fermi surface-induced splitting of the alloy diffuse-scattering intensity peak
The explanation is presented for the temperature dependence of the fourfold
intensity peak splitting found recently in diffuse scattering from the
disordered Cu3Au alloy. The wavevector and temperature dependence of the
self-energy is identified as the origin of the observed behaviour. Two
approaches for the calculation of the self-energy, the high-temperature
expansion and the alpha-expansion, are proposed. Applied to the Cu3Au alloy,
both methods predict the increase of the splitting with temperature, in
agreement with the experimental results.Comment: 4 pages, 3 EPS figures, RevTeX, submitted to J. Phys. Condens. Matter
(Letter to the Editor
A Sensitivity Study of the Enceladus Torus
We have developed a homogeneous model of physical chemistry to investigate
the neutral-dominated, water-based Enceladus torus. Electrons are treated as
the summation of two isotropic Maxwellian distributionsa thermal component
and a hot component. The effects of electron impact, electron recombination,
charge exchange, and photochemistry are included. The mass source is neutral
HO, and a rigidly-corotating magnetosphere introduces energy via pickup of
freshly-ionized neutrals. A small fraction of energy is also input by Coulomb
collisions with a small population ( 1%) of supra-thermal electrons. Mass
and energy are lost due to radial diffusion, escaping fast neutrals produced by
charge exchange and recombination, and a small amount of radiative cooling. We
explore a constrained parameter space spanned by water source rate, ion radial
diffusion, hot-electron temperature, and hot-electron density. The key findings
are: (1) radial transport must take longer than 12 days; (2) water is input at
a rate of 100--180 kg s; (3) hot electrons have energies between 100 and
250 eV; (4) neutrals dominate ions by a ratio of 40:1 and continue to dominate
even when thermal electrons have temperatures as high as 5 eV; (5)
hot electrons do not exceed 1% of the total electron population within the
torus; (6) if hot electrons alone drive the observed longitudinal variation in
thermal electron density, then they also drive a significant variation in ion
composition.Comment: 9 pages text, 3 tables, 9 figure
Neon radiation efficiency for different confinement regimes in TEXTOR-94
For neon seeded discharges the quantity [DeltaP(rad)/DeltaZ(eff)(0)]/)over bar>(2)(e0), which depends linearly on the effective neon cooling rates and which can be taken as a measure of the radiation efficiency of neon, is not a constant for a given machine. When, according to the mode of operation, [[DeltaP(rad)/DeltaZ(eff)(0)]/)over bar>(2)(e0) is high, radiative power exhaust can be efficiently achieved at low Z(eff) The value of this ratio, which we refer to as the quality of neon cooling, is found to be correlated not only with the plasma edge temperature but also, and even more strongly, with the confinement properties of the discharges. Two different high confinement radiative regimes in TEXTOR-94 have been compared: radiative improved (RI) mode (highest confinement) and gas puff/pure radiofrequency mode (slightly lower confinement). Although the electron temperature profile is similar in the two regimes, due to feedback control of the input power level, it has been found experimentally that the quality of neon cooling is lower for the RI mode than for the gas puff/pure radiofrequency one. Similar behaviour has been observed for the quality of cooling of the residual intrinsic carbon, determined with independent diagnostics and methods. Simulations with the self-consistent RITM code confirm that particle transport, in particular the perpendicular diffusivity at the edge, is a key parameter to determine the level of the power radiated at the edge for a given impurity concentration in the plasma core
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