Hearing Loss in Children With Craniofacial Microsomia.

OBJECTIVE: To evaluate the association between craniofacial phenotype and hearing loss in children with craniofacial microsomia. DESIGN: Retrospective cohort study. SETTING: Tertiary care children's hospital. PATIENTS: Individuals with craniofacial microsomia. MAIN OUTCOME MEASURES: Ear-specific audiograms and standardized phenotypic classification of facial characteristics. RESULTS: A total of 79 participants were included in the study. The mean age was 9 years (range, 1 to 23 years) and approximately 60% were boys. Facial anomalies were bilateral in 39 participants and unilateral in 40 participants (24 right, 16 left). Microtia (hypoplasia of the ear) was the most common feature (94%), followed by mandibular hypoplasia (76%), soft tissue deficiency (60%), orbital hypoplasia or displacement (53%), and facial nerve palsy (32%). Sixty-five individuals had hearing loss (12 bilateral and 53 unilateral). Hearing loss was conductive in 73% of affected ears, mixed in 10%, sensorineural in 1%, and indeterminate in 16%. Hypoplasia of the ear or mandible was frequently associated with ipsilateral hearing loss, although contralateral hearing loss occurred in 8% of hemifaces. CONCLUSIONS: Hearing loss is strongly associated with malformations of the ipsilateral ear in craniofacial microsomia and is most commonly conductive. Hearing loss can occur contralaterally to the side with malformations in children with apparent hemifacial involvement. Children with craniofacial microsomia should receive early diagnostic hearing assessments.

Chronic illness burden and quality of life in an aging HIV population.

The population of persons living with HIV (PLWH) is growing older and more prone to developing other chronic health conditions. Disease progression has been shown to be related to quality of life (QoL). However, descriptions of chronic comorbid illnesses and the unique QoL challenges of older adults living with HIV are not well understood and have not been examined in multiple geographic locations. About 452 PLWH aged 50 years or older were recruited from AIDS Service Organizations in nine states. Participants completed a telephone survey that included measures of other chronic health conditions, perceived stress, depression, and health-related quality of life. As much as 94% of the sample reported a chronic health condition in addition to HIV (mode = 2). The highest reported conditions were hypertension, chronic pain, hepatitis, and arthritis. Despite relatively high rates of depression, overall QoL was moderately high for the sample. Physical functioning was most impacted by the addition of other chronic health problems. Social functioning, mental health functioning, stress, and depression were also strongly associated with chronic disease burden. Additional chronic health problems are the norm for PLWH aged 50 years and older. QoL is significantly related to the addition of chronic health problems. As increasing numbers of PLWH reach older age, this raises challenges for providing comprehensive healthcare to older PLWH with multiple chronic conditions.

Means for easy and accurate measurement of the stimulated Brillouin scattering gain coefficient in optical fiber.

We propose and investigate an accurate method for the experimental measurement of the stimulated Brillouin scattering gain coefficient in optical fiber. The gain is extracted from measuring the transmitted pump power at the threshold of stimulated Brillouin scattering (SBS) laser oscillation in a Fabry-Perot cavity formed by Fresnel reflection at the fiber ends. The method is free from a range of uncertainties and difficulties of commonly used approaches and is easy to implement. Experimental evidence of the variation of the SBS gain coefficient with numerical aperture of the fiber, first predicted in [Phys. Rev. Lett. 85, 1879 (2000)], is proven.

Temporally stable continuous-wave phase conjugation by stimulated Brillouin scattering in optical fiber with cavity feedback.

Temporally stable high-fidelity optical phase conjugation by stimulated Brillouin scattering of cw laser radiation is achieved in multimode silica fiber with cavity feedback. A power threshold of approximately 500 mW and a reflectivity of 70% were obtained in a 340-m-long fiber with a cw Nd:YAG laser.

A probabilistic neural network as the predictive classifier of out-of-hospital defibrillation outcomes.

INTRODUCTION: Although modern defibrillators are nearly always successful in terminating ventricular fibrillation (VF), multiple defibrillation attempts are usually required to achieve return of spontaneous circulation (ROSC). This is potentially deleterious as cardiopulmonary resuscitation (CPR) must be discontinued during each defibrillation attempt which causes deterioration in the heart muscle and reduces the chance of ROSC from later defibrillation attempts. In this work defibrillation outcomes are predicted prior to electrical shocks using a neural network model to analyse VF time series in an attempt to avoid defibrillation attempts that do not result in ROSC. METHODS: The 198 pre-shock VF ECG episodes from 83 cardiac arrest patients with defibrillation conversions to different outcomes were selected from the Oslo ambulance service database. A probabilistic neural network model was designed for training and testing with a cross validation method being used for the better generalisation performance. RESULTS: We achieved an accuracy of 75% in overall prediction with a sensitivity of 84% and a specificity of 65% using VF ECG time series of an order of 1 s in length. CONCLUSION: Pre-shock VF ECG time series can be classified according to the defibrillation conversion to a return of spontaneous circulation (ROSC) or No-ROSC.

Origin of temporally stable continuous-wave stokes emission in stimulated Brillouin scattering: evidence of spectral self-phase conjugation.

We report results on the appearance of temporally stable Stokes emission in stimulated Brillouin scattering (SBS) excited by continuous-wave pump radiation in optical fiber. With increasing pump strength the stable component emerges from stochastic emission slightly above the SBS threshold to become the dominant contribution, independent of fiber characteristics. These findings are shown to be a manifestation of spectral self-phase conjugation, providing what is to our knowledge the first experimental evidence of this phenomenon in optics.

300 W quasi-continuous-wave diffraction-limited output from a diode-pumped Nd:YAG master oscillator power amplifier with fiber phase-conjugate stimulated Brillouin scattering mirror.

A master oscillator power amplifier system comprising a cw Nd:YAG master oscillator, a quasi-cw diode-pumped power amplifier, and a fiber-based stimulated Brillouin scattering phase-conjugate mirror is reported. A 12-pass amplifier configuration is employed to achieve high gain in a small-length slab amplifier. Residual and pump-induced optical inhomogeneities in the slab are corrected by the fiber phase conjugator to achieve diffraction-limited output beam quality. 300 W quasi-cw output and a maximal attainable gain of approximately 150 for the system are obtained.

Detection and tracking of small moving objects in image sequences by use of nonlinear spatiotemporal optical systems.

We demonstrate the capability of localized structures of spatiotemporal nonlinear optical systems for detection and tracking of small moving objects. Such nonlinear dynamics based image-processing systems are readily implemented using an existing parallel optoelectronic architecture designed for real-time operation.

Spectral broadening of continuous-wave monochromatic pump radiation caused by stimulated Brillouin scattering in optical fiber.

We experimentally show that, when stimulated Brillouin scattering is generated in optical fiber by use of monochromatic cw pump radiation, the transmitted pump radiation exhibits spectral broadening that is much narrower than the classical homogeneous gain-narrowed Brillouin bandwidth. The bandwidth is practically independent of the pump strength, fiber characteristics, and the waveguide-induced inhomogeneously broadened bandwidth of the Stokes emission. We show that these properties arise from strong parametric coupling of the Stokes and pump signals in the pump-depletion region.

Deterministic nonlinearity in ventricular fibrillation.

We provide numerical evidence that the electrocardiogram data collected from pigs during induced ventricular fibrillation cannot be described by a monotonic nonlinear transformation of linearly filtered noise. To establish this we use surrogate techniques and apply two test statistics: (1) the Takens' maximum likelihood estimator of the Grassberger-Procaccia correlation dimension and (2) an improved correlation dimension estimation routine. The improved dimension estimates provide evidence that the correlation dimension of the underlying dynamics during the episode of VF in the first 30 s is slightly less than 6. This result is consistent and reproducible among subjects. (c) 2000 American Institute of Physics.

Detecting dynamical nonstationarity in time series data.

Nonlinear time series analysis is becoming an ever more powerful tool to explore complex phenomena and uncover underlying patterns from irregular data recorded from experiments. However, the existence of dynamical nonstationarity in time series data causes many results of such analysis to be questionable and inconclusive. It is increasingly recognized that detecting dynamical nonstationarity is a crucial precursor to data analysis. In this paper, we present a test procedure to detect dynamical nonstationarity by directly inspecting the dependence of nonlinear statistical distributions on absolute time along a trajectory in phase space. We test this method using a broad range of data, chaotic, stochastic and power-law noise, both computer-generated and observed, and show that it provides a reliable test method in analyzing experimental data. (c) 1999 American Institute of Physics.