2,187 research outputs found
Entropic uncertainty relations for electromagnetic beams
The symplectic tomograms of 2D Hermite--Gauss beams are found and expressed
in terms of the Hermite polynomials squared. It is shown that measurements of
optical-field intensities may be used to determine the tomograms of
electromagnetic-radiation modes. Furthermore, entropic uncertainty relations
associated with these tomograms are found and applied to establish the
compatibility conditions of the the field profile properties with
Hermite--Gauss beam description. Numerical evaluations for some Hermite--Gauss
modes illustrating the corresponding entropic uncertainty relations are finally
given.Comment: Invited talk at the XV Central European Workshop on Quantum Optics
(Belgrade, Serbia, 30 May -- 3 June 2008), to appear in Physica Scripta
Kidney failure in mice lacking the tetraspanin CD151
The tetraspanin CD151 is a cell-surface molecule known for its strong lateral interaction with the laminin-binding integrin α3β1. Patients with a nonsense mutation in CD151 display end-stage kidney failure associated with regional skin blistering and sensorineural deafness, and mice lacking the integrin α3 subunit die neonatally because of severe abnormalities in the lung and kidney epithelia. We report the generation of Cd151-null mice that recapitulate the renal pathology of human patients, i.e., with age they develop massive proteinuria caused by focal glomerulosclerosis, disorganization of the glomerular basement membrane, and tubular cystic dilation. However, neither skin integrity nor hearing ability are impaired in the Cd151-null mice. Furthermore, we generated podocyte-specific conditional knockout mice for the integrin α3 subunit that show renal defects similar to those in the Cd151 knockout mice. Our results support the hypothesis that CD151 plays a key role in strengthening α3β1-mediated adhesion in podocytes
Treatment of Intrusive Suicidal Imagery Using Eye Movements
Suicide and suicidal behavior are major public health concerns, and affect 3–9% of the population worldwide. Despite increased efforts for national suicide prevention strategies, there are still few effective interventions available for reducing suicide risk. In this article, we describe various theoretical approaches for suicide ideation and behavior, and propose to examine the possible effectiveness of a new and innovative preventive strategy. A model of suicidal intrusion (mental imagery related to suicide, also referred to as suicidal flash-forwards) is presented describing one of the assumed mechanisms in the etiology of suicide and the mechanism of therapeutic change. We provide a brief rationale for an Eye Movement Dual Task (EMDT) treatment for suicidal intrusions, describing techniques that can be used to target these suicidal mental images and thoughts to reduce overall behavior. Based on the available empirical evidence for the mechanisms of suicidal intrusions, this approach appears to be a promising new treatment to prevent suicidal behavior as it potentially targets one of the linking pins between suicidal ideation and suicidal actions
Integrated stratigraphical study of the Rhuddanian-Aeronian (Llandovery, Silurian) boundary succession in the Rheidol Gorge, Wales:A proposed Global Stratotype Section and Point for the base of the Aeronian Stage
The Rheidol Gorge section, approximately 17 km east of Aberystwyth, mid Wales, exposes a ca. 20 m-thick succession of Llandovery (Silurian) strata from the upper Rhuddanian Pernerograptus revolutus Biozone through the lower Aeronian Demirastrites triangulatus Biozone and basal Neodiplograptus magnus Biozone. The section records deposition under a range of bottom-water oxygenation states. The Rhuddanian-Aeronian boundary is located 0.8 m above an abrupt lithological change from predominantly organic-poor, bioturbated `oxic' mudrocks to an interval of black, richly graptolitic `anoxic' shales. The graptolite fauna through the boundary interval, including the local lowest occurrence of D. triangulatus, allows precise correlation with other parts of the world. Graptolite assemblages indicative of separate divisions in the underlying revolutus Biozone and of the lower and upper parts of the triangulatus Biozone are also present. Chitinozoans are relatively well preserved in the section and indicate the Spinachitina maennili Biozone throughout the boundary interval, as is widely the case. The results of carbon isotope analyses from organic matter indistinctly show the weak interval of positive shift in d13C org values through the Rhuddanian-Aeronian boundary interval, as observed globally, though local or regional processes appear largely to overprint the global signal. Overall, the excellent biostratigraphical record, well-documented local and regional stratigraphical context, historical significance, as well as easy access and assured longterm preservation, mean that the Rheidol Gorge section can be proposed as a strong candidate for a new Global Stratotype Section and Point for the base of the Aeronian Stage.. Silurian, Llandovery, Rhuddanian, Aeronian, Global Stratotype Section and Point, Graptolites, Chitinozoa, Carbon Isotope
Stochastic collective dynamics of charged--particle beams in the stability regime
We introduce a description of the collective transverse dynamics of charged
(proton) beams in the stability regime by suitable classical stochastic
fluctuations. In this scheme, the collective beam dynamics is described by
time--reversal invariant diffusion processes deduced by stochastic variational
principles (Nelson processes). By general arguments, we show that the diffusion
coefficient, expressed in units of length, is given by ,
where is the number of particles in the beam and the Compton
wavelength of a single constituent. This diffusion coefficient represents an
effective unit of beam emittance. The hydrodynamic equations of the stochastic
dynamics can be easily recast in the form of a Schr\"odinger equation, with the
unit of emittance replacing the Planck action constant. This fact provides a
natural connection to the so--called ``quantum--like approaches'' to beam
dynamics. The transition probabilities associated to Nelson processes can be
exploited to model evolutions suitable to control the transverse beam dynamics.
In particular we show how to control, in the quadrupole approximation to the
beam--field interaction, both the focusing and the transverse oscillations of
the beam, either together or independently.Comment: 15 pages, 9 figure
Default Risk and Equity Returns: A Comparison of the Bank-Based German and the U.S. Financial System
In this paper, we address the question whether the impact of default risk on equity returns depends on the financial system firms operate in. Using an implementation of Merton's option-pricing model for the value of equity to estimate firms' default risk, we construct a factor that measures the excess return of firms with low default risk over firms with high default risk. We then compare results from asset pricing tests for the German and the U.S. stock markets. Since Germany is the prime example of a bank-based financial system, where debt is supposedly a major instrument of corporate governance, we expect that a systematic default risk effect on equity returns should be more pronounced for German rather than U.S. firms. Our evidence suggests that a higher firm default risk systematically leads to lower returns in both capital markets. This contradicts some previous results for the U.S. by Vassalou/Xing (2004), but we show that their default risk factor looses its explanatory power if one includes a default risk factor measured as a factor mimicking portfolio. It further turns out that the composition of corporate debt affects equity returns in Germany. Firms' default risk sensitivities are attenuated the more a firm depends on bank debt financing
Impact of differing methodologies for serum miRNA-371a-3p assessment in stage I testicular germ cell cancer recurrence
INTRODUCTION
Current evidence shows that serum miR-371a-3p can identify disease recurrence in testicular germ cell tumour (TGCT) patients and correlates with tumour load. Despite convincing evidence showing the advantages of including miR-371a-3p testing to complement and overcome the classical serum tumour markers limitations, the successful introduction of a serum miRNA based test into clinical practice has been impeded by a lack of consensus regarding optimal methodologies and lack of a universal protocol and thresholds. Herein, we investigate two quantitative real-time PCR (qRT-PCR) based pipelines in detecting disease recurrence in stage I TGCT patients under active surveillance, and compare the sensitivity and specificity for each method.
METHODS
Sequential serum samples collected from 33 stage I TGCT patients undergoing active surveillance were analysed for miR-371a-3p via qRT-PCR with and without an amplification step included.
RESULTS
Using a pre-amplified protocol, all known recurrences were detected via elevated miR-371a-3p expression, while without pre-amplification, we failed to detect recurrence in 3/10 known recurrence patients. For pre-amplified analysis, sensitivity and specificity was 90% and 94.4% respectively. Without amplification, sensitivity dropped to 60%, but exhibited 100% specificity.
DISCUSSION
We conclude that incorporating pre-amplification increases sensitivity of miR-371a-3p detection, but produces more false positive results. The ideal protocol for quantification of miR-371a-3p still needs to be determined. TGCT patients undergoing active surveillance may benefit from serum miR-371a-3p quantification with earlier detection of recurrences compared to current standard methods. However, larger cross-institutional studies where samples are processed and data is analysed in a standardised manner are required prior to its routine clinical implementation
Impact of differing methodologies for serum miRNA-371a-3p assessment in stage I testicular germ cell cancer recurrence.
INTRODUCTION
Current evidence shows that serum miR-371a-3p can identify disease recurrence in testicular germ cell tumour (TGCT) patients and correlates with tumour load. Despite convincing evidence showing the advantages of including miR-371a-3p testing to complement and overcome the classical serum tumour markers limitations, the successful introduction of a serum miRNA based test into clinical practice has been impeded by a lack of consensus regarding optimal methodologies and lack of a universal protocol and thresholds. Herein, we investigate two quantitative real-time PCR (qRT-PCR) based pipelines in detecting disease recurrence in stage I TGCT patients under active surveillance, and compare the sensitivity and specificity for each method.
METHODS
Sequential serum samples collected from 33 stage I TGCT patients undergoing active surveillance were analysed for miR-371a-3p via qRT-PCR with and without an amplification step included.
RESULTS
Using a pre-amplified protocol, all known recurrences were detected via elevated miR-371a-3p expression, while without pre-amplification, we failed to detect recurrence in 3/10 known recurrence patients. For pre-amplified analysis, sensitivity and specificity was 90% and 94.4% respectively. Without amplification, sensitivity dropped to 60%, but exhibited 100% specificity.
DISCUSSION
We conclude that incorporating pre-amplification increases sensitivity of miR-371a-3p detection, but produces more false positive results. The ideal protocol for quantification of miR-371a-3p still needs to be determined. TGCT patients undergoing active surveillance may benefit from serum miR-371a-3p quantification with earlier detection of recurrences compared to current standard methods. However, larger cross-institutional studies where samples are processed and data is analysed in a standardised manner are required prior to its routine clinical implementation
Определение интервалов квазистационарности экономических систем
В работе рассмотрен вопрос определения оптимального интервала адаптации алгоритма динамического управления капиталом для нестационарного случая методами расчета показателя Херста и построения автокорреляционной функции для анализа временных рядов. Проведен анализ влияния выбора интервала адаптации на эффективность алгоритма. Из анализа полученных результатов следует, что метод расчета показателя Херста позволяет более эффективно, чем метод построения автокорреляционной функции, определить интервал стационарности модели функционирования экономической системы.Робота присвячена питанню визначення оптимального інтервалу адаптації алгоритму динамічного керування капіталом для нестаціонарного випадку за допомогою методів розрахунку показника Херста і побудови автокореляційної функції задля аналізу часових рядів. Проведено аналіз впливу вибору інтервалу адаптації на ефективність алгоритму. Порівняння результатів проведеного аналізу дозволяє стверджувати, що метод розрахунку показника Херста дозволяє більш ефективно, ніж метод побудови автокореляційної функції, визначити інтервал стаціонарності моделі функціонування економічної системи
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