4,346 research outputs found

    Clinical Experience and Sexual Function Outcome of Patients With Priapism Treated With Penile Cavernosal-Dorsal Vein Shunt Using Saphenous Vein Graft

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    OBJECTIVES To assess the outcome of new penile cavernosal-dorsal vein shunt using a saphenous vein graft. Traditional surgeries for priapism have high failure rate and subsequent impotence. METHODS We reviewed the medical records of, and administered a questionnaire and the International Index of Erectile Function to, 16 consecutive patients with priapism who had treated with the penile cavernosal-dorsal vein shunt from 1997 to 2007. Their age was 15-65 years. The duration of ischemic priapism was 32 hours to 8 days. Ten patients had previously undergone shunt surgery by other urologists. Of the 16 patients, 5 returned the questionnaires. RESULTS Priapism resolved or was improved after surgery in all 16 patients. One patient was lost to follow-up. One pediatric patient was excluded from the analysis. One patient with nonischemic priapism continued to have sexual intercourse. Of the 13 adult patients with ischemic priapism and follow-up for ≤ 6.5 years, 3 patients had no erection, 1 had very little erection, and 9 (69%) had erection. Of the 9 patients with erections possible, six had had sexual intercourse (International Index of Erectile Function score 32-70) and 3 had not; 1 had a mental disorder, 1 was in prison, and for 1, the reason was unknown. After surgery, color Doppler ultrasound studies showed a patent shunt in all patients and restoration of cavernosal arterial flow in 12 of 13 patients studied. CONCLUSIONS A penile cavernosal-dorsal shunt appears effective for priapism. It resulted in priapism resolution even in patients who had experienced a previous failed cavernosal-glandular shunt or cavernosalspongiosal shunt, with a high rate of sexual function preservation

    Effective dynamics of the closed loop quantum cosmology

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    In this paper we study dynamics of the closed FRW model with holonomy corrections coming from loop quantum cosmology. We consider models with a scalar field and cosmological constant. In case of the models with cosmological constant and free scalar field, dynamics reduce to 2D system and analysis of solutions simplify. If only free scalar field is included then universe undergoes non-singular oscillations. For the model with cosmological constant, different behaviours are obtained depending on the value of Λ\Lambda. If the value of Λ\Lambda is sufficiently small, bouncing solutions with asymptotic de Sitter stages are obtained. However if the value of Λ\Lambda exceeds critical value Λc=3mPl22πγ3≃21mPl2\Lambda_{\text{c}} =\frac{\sqrt{3}m^2_{\text{Pl}}}{2\pi\gamma^3} \simeq 21 m^2_{\text{Pl}} then solutions become oscillatory. Subsequently we study models with a massive scalar field. We find that this model possess generic inflationary attractors. In particular field, initially situated in the bottom of the potential, is driven up during the phase of quantum bounce. This subsequently leads to the phase of inflation. Finally we find that, comparing with the flat case, effects of curvature do not change qualitatively dynamics close to the phase of bounce. Possible effects of inverse volume corrections are also briefly discussed.Comment: 18 pages, 11 figure

    Democratizing China and Taiwan: Cultural and Institutional Paradigms

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    Maoist militant revolution died with Mao on 9 September 1976. Deng Xioaping's political reform, in spite of the great expectations it raised by the 1979-89 modernization push, met an equally tragic death on 4 June 1989, when he sent in his tanks to crush the peaceful pro-democracy demonstration in Tiananmen Square. Before 3 June no one foresaw that the 1989 pro-democracy movement would end up more disastrously that its equally famous forerunner,m the May 4 Movement, exactly seventy years earlier in 1919. Of course, there are many differences between the two movements, but there are also many fundamental similarities. The most salient and remarkable similarity between the two historic events, which should cause the most soul-searching among the Chinese people. particularly the intellectuals, is the tragic, almost fatalistic, way the intellectuals' attempts at democratizing China met a tragic fate at the hands of the similar traditional Chinese authoritarian political despots. In terms of democratization, which was the principal modernization goal of the May 4 Movement, the Chinese reformist elites, both cultural and political, achieve very little in their seventy-year long and painful struggles. (First paragraph of Introduction)

    Foldy-Wouthuysen transformation for a Dirac-Pauli dyon and the Thomas-Bargmann-Michel-Telegdi equation

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    The classical dynamics for a charged point particle with intrinsic spin is governed by a relativistic Hamiltonian for the orbital motion and by the Thomas-Bargmann-Michel-Telegdi equation for the precession of the spin. It is natural to ask whether the classical Hamiltonian (with both the orbital and spin parts) is consistent with that in the relativistic quantum theory for a spin-1/2 charged particle, which is described by the Dirac equation. In the low-energy limit, up to terms of the 7th order in 1/Eg1/E_g (Eg=2mc2E_g=2mc^2 and mm is the particle mass), we investigate the Foldy-Wouthuysen (FW) transformation of the Dirac Hamiltonian in the presence of homogeneous and static electromagnetic fields and show that it is indeed in agreement with the classical Hamiltonian with the gyromagnetic ratio being equal to 2. Through electromagnetic duality, this result can be generalized for a spin-1/2 dyon, which has both electric and magnetic charges and thus possesses both intrinsic electric and magnetic dipole moments. Furthermore, the relativistic quantum theory for a spin-1/2 dyon with arbitrary values of the gyromagnetic and gyroelectric ratios can be described by the Dirac-Pauli equation, which is the Dirac equation with augmentation for the anomalous electric and anomalous magnetic dipole moments. The FW transformation of the Dirac-Pauli Hamiltonian is shown, up to the 7th order again, to be also in accord with the classical Hamiltonian.Comment: 18 page

    Democratising China and Taiwan: cultural and institutional paradigms

    No full text
    Maoist militant revolution died with Mao on 9 September 1 976. Deng Xioaping's political reform, in spite of the great expectations it raised by the 1979-89 modernization push, met an equally tragic death on 4 June 1 989, when he sent in his tanks to crush the peaceful pro-democracy demonstration in Tiananmen Square. Before 3 June no one foresaw that the 1989 pro-democracy movement would end up more disastrously than its equally famous forerunner, the May 4 Movement, exactly seventy years earlier in 191 9. Of course, there are many differences between the two movements, but there are also many fundamental similarities. The most salient and remarkable similarity between the two historic events, which should cause the most soul-searching among the Chinese people, particularly the intellectuals, is the tragic, almost fatalistic, way the intellectuals' attempts at democratizing China met a tragic fate at the hands of the similar traditional Chinese authoritarian political despots. In terms of democratization, which was the principal modernization goal of the May 4 Movement, the Chinese reformist elites, both cultural and political, achieved very little in their seventy year long and painful struggles

    Using Virtual Instrument in Teaching Automatic Measurement Technology Course

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    The use of an automatic measurement technology is highly important in current industries. The technology has been sued in various applications such as environment monitoring, quality control of production line, and medical disease analysis. Automatic measurement technology requires programming, facilities integration, control application, function innovation, and maintenance technology. Developing suitable teaching equipment that can satisfy the demand of industry-orientation Automatic Measurement Technology Course (AMTC) is a challenge. In this study, a virtual instrument is introduced to solve the problem. LabVIEW, which is utilized to design virtual instruments, provides powerful functions for instrument control and measurement. Therefore, in this proposed AMTC, anbsp LabVIEW-based virtual instrument system is established as teaching equipment for undergraduate students in colleges of engineering or technology

    Fine structure and optical properties of biological polarizers in crustaceans and cephalopods

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    The lighting of the underwater environment is constantly changing due to attenuation by water, scattering by suspended particles, as well as the refraction and reflection caused by the surface waves. These factors pose a great challenge for marine animals which communicate through visual signals, especially those based on color. To escape this problem, certain cephalopod mollusks and stomatopod crustaceans utilize the polarization properties of light. While the mechanisms behind the polarization vision of these two animal groups are similar, several distinctive types of polarizers (i.e. the structure producing the signal) have been found in these animals. To gain a better knowledge of how these polarizers function, we studied the relationships between fine structures and optical properties of four types of polarizers found in cephalopods and stomatopods. Although all the polarizers share a somewhat similar spectral range, around 450- 550 nm, the reflectance properties of the signals and the mechanisms used to produce them have dramatic differences. In cephalopods, stack-plates polarizers produce the polarization patterns found on the arms and around their eyes. In stomatopods, we have found one type of beam-splitting polarizer based on photonic structures and two absorptive polarizer types based on dichroic molecules. These stomatopod polarizers may be found on various appendages, and on the cuticle covering dorsal or lateral sides of the animal. Since the efficiencies of all these polarizer types are somewhat sensitive to the change of illumination and viewing angle, how these animals compensate with different behaviors or fine structural features of the polarizer also varies

    Quantum Mechanical Search and Harmonic Perturbation

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    Perturbation theory in quantum mechanics studies how quantum systems interact with their environmental perturbations. Harmonic perturbation is a rare special case of time-dependent perturbations in which exact analysis exists. Some important technology advances, such as masers, lasers, nuclear magnetic resonance, etc., originated from it. Here we add quantum computation to this list with a theoretical demonstration. Based on harmonic perturbation, a quantum mechanical algorithm is devised to search the ground state of a given Hamiltonian. The intrinsic complexity of the algorithm is continuous and parametric in both time T and energy E. More precisely, the probability of locating a search target of a Hamiltonian in N-dimensional vector space is shown to be 1/(1+ c N E^{-2} T^{-2}) for some constant c. This result is optimal. As harmonic perturbation provides a different computation mechanism, the algorithm may suggest new directions in realizing quantum computers.Comment: 6 pages, 4 figures, revtex
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