Optical-parametric-oscillator solitons driven by the third harmonic

We introduce a model of a lossy second-harmonic-generating (chi^2) cavity externally pumped at the third harmonic, which gives rise to driving terms of a new type, corresponding to a cross-parametric gain. The equation for the fundamental-frequency (FF) wave may also contain a quadratic self-driving term, which is generated by the cubic nonlinearity of the medium. Unlike previously studied phase-matched models of chi^2 cavities driven at the second harmonic (SH) or at FF, the present one admits an exact analytical solution for the soliton, at a special value of the gain parameter. Two families of solitons are found in a numerical form, and their stability area is identified through numerical computation of the perturbation eigenvalues (stability of the zero solution, which is a necessary condition for the soliton's stability, is investigated in an analytical form). One family is a continuation of the special analytical solution. At given values of parameters, one soliton is stable and the other one is not; they swap their stability at a critical value of the mismatch parameter. The stability of the solitons is also verified in direct simulations, which demonstrate that the unstable pulse rearranges itself into the stable one, or into a delocalized state, or decays to zero. A soliton which was given an initial boost C starts to move but quickly comes to a halt, if the boost is smaller than a critical value C_cr. If C>C_cr, the boost destroys the soliton (sometimes, through splitting into two secondary pulses). Interactions between initially separated solitons are investigated too. It is concluded that stable solitons always merge into a single one. In the system with weak loss, it appears in a vibrating form, slowly relaxing to the static shape. With stronger loss, the final soliton emerges in the stationary form.Comment: Latex file, 22 pages, 18 figures (33 figures files

Multi-soliton states under triangular spatial modulation of the quadratic nonlinearity

We introduce multi-soliton sets in the two-dimensional medium with the second-harmonic-generating nonlinearity subject to spatial modulation in the form of a triangle of singular peaks. Various families of symmetric and asymmetric sets are constructed, and their stability is investigated. Stable symmetric patterns may be built of 1, 4, or 7 individual solitons, while stable asymmetric ones contain 1, 2, or 3 solitons. Symmetric and asymmetric patterns may demonstrate mutual bistability. The shift of the asymmetric single-soliton state from the central position is accurately predicted analytically. Vortex rings composed of three solitons are produced too.Comment: to be published in Eur. Phys. J. Special Topics (special issue "Nonlinear Dynamics in Physics: New Techniques and Applications"

Pneumonia Due to Mycoplasma in Gnotobiotic Mice I. Pathogenicity of \u3cem\u3eMycoplasma pneumoniae\u3c/em\u3e, \u3cem\u3eMycoplasma salivarium\u3c/em\u3e, and \u3cem\u3eMycoplasma pulmonis\u3c/em\u3e for the Lungs of Conventional and Gnotobiotic Mice

Pneumonia due to mycoplasma in gnotobiotic mice. I. Pathogenicity of Mycoplasma pneumoniae, Mycoplasma salivarium, and Mycoplasma pulmonis for the lungs of conventional and gnotobiotic mice. J. Bacteriol. 92:1154–1163. 1966.—Two species of mycoplasma of human origin, Mycoplasma pneumoniae and M. salivarium, were tested for their ability to produce respiratory disease in the Ha/ICR mouse when inoculated by the intranasal route. The mouse pathogen M. pulmonis was studied as a positive control. Conventional and gnotobiotic Ha/ICR mice were employed, the latter to provide a system free from indigenous mycoplasma and bacteria. Pneumonia from which mycoplasma were isolated was produced in all groups of the conventional Ha/ICR mice, including those inoculated with sterile broth. Only M. pulmonis produced disease when inoculated intranasally into the gnotobiotic mice, and the gross and microscopic lesions resembled those described in conventional mice. The gnotobiotic mouse provided a tool to study the pathogenicity of different mycoplasma species, and indicated marked differences in host specificity that could not be clearly seen when conventional mice were used

Radio astronomy Explorer-B in-flight mission control system development effort

A description is given of the development for the Mission Analysis Evaluation and Space Trajectory Operations (MAESTRO) program to be used for the in-flight decision making process during the translunar and lunar orbit adjustment phases of the flight of the Radio Astronomy Explorer-B. THe program serves two functions: performance and evaluation of preflight mission analysis, and in-flight support for the midcourse and lunar insertion command decisions that must be made by the flight director. The topics discussed include: analysis of program and midcourse guidance capabilities; methods for on-line control; printed displays of the MAESTRO program; and in-flight operational logistics and testing

New Fundamental dHvA Frequency in Canonical Low-Dimensional Fermi Liquids

We show that a new fundamental period $P_{f}$ of dHvA oscillations, which appears along with other ``forbidden'' combination frequencies in a multi-band canonical Fermi-liquid, is very robust with respect to a finite smearing of Landau levels and a background of non-quantized states. We analyse the possibility of measuring small Fermi surface pockets with the use of the ``forbidden'' frequencies.Comment: 10 pages, RevTeX 3.0, with 2 PS Figure

A Prospective Evaluation of Opioid Utilization After Upper-Extremity Surgical Procedures: Identifying Consumption Patterns and Determining Prescribing Guidelines.

BACKGROUND: Although adequate management of postoperative pain with oral analgesics is an important aspect of surgical procedures, inadvertent overprescribing can lead to excess availability of opioids in the community for potential diversion. The purpose of our study was to prospectively evaluate opioid consumption following outpatient upper-extremity surgical procedures to determine opioid utilization patterns and to develop prescribing guidelines. METHODS: All patients undergoing outpatient upper-extremity surgical procedures over a consecutive 6-month period had the following prospective data collected: patient demographic characteristics, surgical details, anesthesia type, and opioid prescription and consumption patterns. Analysis of variance and post hoc comparisons were performed using t tests, with the p value for multiple pairwise tests adjusted by the Bonferroni correction. RESULTS: A total of 1,416 patients with a mean age of 56 years (range, 18 to 93 years) were included in the study. Surgeons prescribed a mean total of 24 pills, and patients reported consuming a mean total of 8.1 pills, resulting in a utilization rate of 34%. Patients undergoing soft-tissue procedures reported requiring fewer opioids (5.1 pills for 2.2 days) compared with fracture surgical procedures (13.0 pills for 4.5 days) or joint procedures (14.5 pills for 5.0 days) (p \u3c 0.001). Patients who underwent wrist surgical procedures required a mean number of 7.5 pills for 3.1 days and those who underwent hand surgical procedures required a mean number of 7.7 pills for 2.9 days, compared with patients who underwent forearm or elbow surgical procedures (11.1 pills) and those who underwent upper arm or shoulder surgical procedures (22.0 pills) (p \u3c 0.01). Procedure type, anatomic location, anesthesia type, age, and type of insurance were also all significantly associated with reported opioid consumption (p \u3c 0.001). CONCLUSIONS: In this large, prospective evaluation of postoperative opioid consumption, we found that patients are being prescribed approximately 3 times greater opioid medications than needed following upper-extremity surgical procedures. We have provided general prescribing guidelines, and we recommend that surgeons carefully examine their patients\u27 opioid utilization and consider customizing their opioid prescriptions on the basis of anatomic location and procedure type to prescribe the optimal amount of opioids while avoiding dissemination of excess opioids