676 research outputs found
Third Cumulant of the total Transmission of diffuse Waves
The probability distribution of the total transmission is studied for waves
multiple scattered from a random, static configuration of scatterers. A
theoretical study of the second and third cumulant of this distribution is
presented. Within a diagrammatic approach a theory is developed which relates
the third cumulant normalized to the average, , to the normalized second cumulant . For a broad Gaussian beam profile it is found that .
This is in good agreement with data of optical experiments.Comment: 16 pages revtex, 8 separate postscript figure
The Effects of Possible Contamination on the Radiocarbon Dating of the Dead Sea Scrolls II: Empirical Methods to Remove Castor Oil and Suggestions for Redating
While kept at the Rockefeller Museum in East Jerusalem, many Dead Sea Scroll fragments were exposed to castor oil by the original team of editors in the course of cleaning the parchments. Castor oil must be regarded as a serious contaminant in relation to radiocarbon dating. If modern castor oil is present and is not removed prior to dating, the 14C dates will be skewed artificially towards modern values. Earlier, it was shown that the standard AAA pretreatment procedure used in the 2 previous studies dating Dead Sea Scroll samples is not capable of removing castor oil from parchment samples. In the present work, we show that it is unlikely that castor oil reacts with the amino acids of the parchment proteins, a finding which leaves open the possibility of devising a cleaning method that can effectively remove castor oil. We then present 3 different pretreatment protocols designed to effectively remove castor oil from parchment samples. These involve 3 different cleaning techniques: extraction with supercritical CO2, ultrasound cleaning, and Soxhlet extraction—each with their own advantages and disadvantages. Our data show that the protocol involving Soxhlet extraction is the best suited for the purpose of decontaminating the Dead Sea Scrolls, and we recommend that this protocol be used in further attempts to 14C date the Dead Sea Scrolls. If such an attempt is decided on by the proper authorities, we propose a list of Scroll texts, which we suggest be redated in order to validate the 14C dates done earlier.
Особенности движения метановоздушной смеси в дегазационном трубопроводе
Розглянуто ізотермічне та неізотермічне турбулентний рух метаноповітряної суміші в
дільничному дегазаційному трубопроводі.Isothermal and non isothermal considered the motion methane-air mixture in the decontamination
line
Knowledge-based semantic annotation and retrieval of multimedia content
aceMedia is a 4 year EC part-funded FP6 Integrated Project, ending in December 2007. The project has developed tools to enable users to manage and share both personal and purchased content across PC, STB and mobile platforms. Knowledge-based analysis and ontologies have been successfully exploited in an end-to-end system to enable automated semantic annotation and retrieval of multimedia content. The paper briefly describes the objectives of aceMedia and the application of knowledge-based analysis in the project
A solvable model of a random spin-1/2 XY chain
The paper presents exact calculations of thermodynamic quantities for the
spin-1/2 isotropic XY chain with random lorentzian intersite interaction and
transverse field that depends linearly on the surrounding intersite
interactions.Comment: 14 pages (Latex), 2 tables, 13 ps-figures included, (accepted for
publication in Phys.Rev.B
Osmotic swelling-induced activation of the extracellular-signal-regulated protein kinases Erk-1 and Erk-2 in intestine 407 cells involves the Ras/Raf-signalling pathway
Human Intestine 407 cells respond to hypo-osmotic stress with a rapid
stimulation of compensatory ionic conductances accompanied by a transient
increase in the activity of the extracellular-signal-regulated protein
kinases Erk-1 and Erk-2. In this study, we examined the upstream
regulators of hypotonicity-induced Erk-1/Erk-2 activation and their
possible role in cell-volume regulation. The hypotonicity-provoked
Erk-1/Erk-2 activation was greatly reduced in cells pretreated with the
specific mitogen-activated/Erk-activating kinase inhibitor PD098059 and
was preceded by a transient stimulation of Raf-1. Pretreatment of the
cells with PMA, GF109203X, wortmannin or Clostridium botulinum C3
exoenzyme did not appreciably affect the hypotonicity-provoked Erk-1/Erk-2
stimulation, suggesting the osmosensitive signalling pathway to be largely
independent of protein kinase C and p21(rho). In contrast, expression of
dominant negative RasN17 completely abolished the hypotonicity-induced
Erk-1/Erk-2 activation. Stimulation of the swelling-induced ion efflux was
independent of activation of these mitogen-activated protein kinases, as
revealed by hypotonicity-provoked isotope efflux from 125I-- and
86Rb+-loaded cells after pretreatment with PD098059 and after
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