Behavior of the PMD coefficient of optical links under influence of mechanical and thermal effects

This papers presents results on the variation of the PMD coefficient of optical links under influence of mechanical tests, such as tensile strength, bending and compression, and also during the application of a thermal cycle. Results revealed that the link coefficient is more influenced by the application of a tension load and also suffers significant variation under strong temperature changes. Copyrigth © SBMO.

Berührungslose Oberflächenerfassung mittels PMD-Kameratechnologie im Braunkohletagebau

In Zusammenarbeit mit der RWE-Power AG forscht das Institut für Transport- und Automatisierungstechnik am Einsatz der PMD-Kameratechnologie zur berührungslosen Umgebungserfassung im industriellen Umfeld. Ziel ist, am Beispiel des Einsatzes bei der Braunkohleförderung mittels eines Schaufelradbaggers, die Umgebung des Abbaugerätes zu erfassen und im Modell darzustellen. Zu diesem Zweck wurde im Braunkohletagebau an einem Schaufelradbagger eine Messeinrichtung aufgebaut, die es ermöglichen soll, während des Gewinnungsprozesses die Tagebauoberfläche zu erfassen. Der Aufbau und der aktuelle Stand der Messungen werden im Beitrag vorgestellt.

PMD fundamentals: Polarization mode dispersion in optical fibers

This paper reviews the fundamental concepts and basic theory of polarization mode dispersion (PMD) in optical fibers. It introduces a unified notation and methodology to link the various views and concepts in Jones space and Stokes space. The discussion includes the relation between Jones vectors and Stokes vectors, rotation matrices, the definition and representation of PMD vectors, the laws of infinitesimal rotation, and the rules for PMD vector concatenation.

Integration of the Manakov-PMD Equation with Precomputed M(w) Matrices for PMD Simulation

A novel direct integration technique of the Manakov-PMD equation for the simulation of polarisation mode dispersion (PMD) in optical communication systems is demonstrated and shown to be numerically as efficient as the commonly used coarse-step method. The main advantage of using a direct integration of the Manakov-PMD equation over the coarse-step method is a higher accuracy of the PMD model. The new algorithm uses precomputed M(w) matrices to increase the computational speed compared to a full integration without loss of accuracy. The simulation results for the probability distribution function (PDF) of the differential group delay (DGD) and the autocorrelation function (ACF) of the polarisation dispersion vector for varying numbers of precomputed M(w) matrices are compared to analytical models and results from the coarse-step method. It is shown that the coarse-step method achieves a significantly inferior reproduction of the statistical properties of PMD in optical fibres compared to a direct integration of the Manakov-PMD equation.

Application of the manakov-PMD equation to a computational investigation of low-PMD fibres

The phenomenon of low-PMD fibres is examined through numerical simulations. Instead of the coarse-step method we are using an algorithm developed through the Manakov-PMD equation. With the integration of the Manakov-PMD equation we have access to the fibre spin which relates to the orientation of the birefringence. The simulation results produced correspond to the behaviour of a low-PMD spun fibre. Furthermore we provide an analytical approximation compared to the numerical data. © 2005 Optical Society of America.

Numerical implementation of the Manakov-PMD equation with precomputed M(Ω) matrices

The Manakov-PMD equation can be integrated with the same numerical efficiency as the coarse-step method by using precomputed M(Ω) matrices, which entirely avoids the somewhat ad-hoc rescaling of coefficients necessary in the coarse-step method.

PMD tolerance of 288 Gbit/s Coherent WDM and transmission over unrepeatered 124 km of field-installed single mode optical fiber

Low-cost, high-capacity optical transmission systems are required for metropolitan area networks. Direct-detected multi-carrier systems are attractive candidates, but polarization mode dispersion (PMD) is one of the major impairments that limits their performance. In this paper, we report the first experimental analysis of the PMD tolerance of a 288Gbit/s NRZ-OOK Coherent Wavelength Division Multiplexing system. The results show that this impairment is determined primarily by the subcarrier baud rate. We confirm the robustness of the system to PMD by demonstrating error-free performance over an unrepeatered 124km field-installed single-mode fiber with a negligible penalty of 0.3dB compared to the back-to-back measurements. (C) 2010 Optical Society of America

Numerical implementation of low-PMD spun fibres with precomputed M(w) matrices

Poster With the use of the coarse-step method for simulating the phenomenon of PMD the fibre-twist as not included into the equations. This was an obstacle in representing low-PMD spun fibres numerially.

PMD tolerant nonlinear compensation using in-line phase conjugation

In this paper, we numerically investigate the impact of polarisation mode dispersion on the efficiency of compensation of nonlinear transmission penalties for systems employing one of more inline phase conjugation devices. We will show that reducing the spacing between phase conjugations allows for significantly improved performance in the presence polarisation mode dispersion or a significant relaxation in the acceptable level of polarization mode dispersion. We show that these results are consistent with previously presented full statistical analysis of nonlinear transmission appropriately adjusted for the reduced section length undergoing compensation.

Differential contributions of the mIPS and PMd in the movement planning of reaches investigated through HD-tDCS

To reach for a target, we must formulate a movement plan - a difference vector of the target position with respect to the starting hand position. While it is known that the medial part of the intraparietal sulcus (mIPS) and the dorsal premotor (PMd) activity reflects aspects of a kinematic plan for a reaching movement, it is unclear whether or how the two regions may differ. We investigated the functional roles of the mIPS and PMd in the planning of reaching movements using high definition transcranial direct current stimulation (HD-tDCS) and examined changes in horizontal endpoint error when participants were subjected to anodal and cathodal stimulation. The left mIPS and PMd were functionally localized with fMRI in each participant using an interleaved center-out pointing and saccade task and mapped onto the scalp using Brainsight. We adopted a randomized, single-blind design and applied anodal and cathodal stimulation (2mA for 20 min; 3cm radius 4x1 electrode placement) during 4 separate visits scheduled at least a week apart. Each participant performed 250 baseline, stimulation, and post-stimulation memory-guided reaches starting from one of two initial hand positions (IHPs) to one of 4 briefly flashed targets (20 cm distant, 5 cm apart horizontally) while fixating on a straight-ahead cross located at the target line. Separate 2-way repeated measures ANOVAs of horizontal endpoint error difference after cathodal tDCS at each stimulation site revealed a significant IHP by target position interaction effect at the left mIPS, and significant IHP and target main effects at the left PMd. Behaviorally, these effects corresponded to IHP-dependent contractions after cathodal mIPS tDCS and IHP-independent contractions after cathodal PMd tDCS. These results suggest that the movement vector is not yet formed at the input level of mIPS, but is encoded at the input of PMd. These results also indicate that tDCS is a viable, useful method in investigating movement planning properties through temporary perturbations of the system.

Consulta de Enfermagem ao doente portador de PMD e CDI

Os cuidados de saúde sempre se pautaram por uma indissociável ligação ao constante desenvolvimento do conhecimento científico médico e de enfermagem, com a particularidade de, nos últimos anos, ter sido acompanhado por um desenvolvimento biotecnológico que tem permitido melhorar a qualidade de vida dos portadores de doença crónica, nomeadamente os indivíduos com patologia cardíaca. Através da evolução dos dispositivos implantáveis como pacemakers, cardioversores desfibrilhadores e geradores de ressincronização cardíaca, foi possível prolongar a vida e melhorar a sua qualidade em doenças que no início do século XX matavam muitas pessoas. Apesar da implantação destes dispositivos não implicar uma alteração importante no estilo de vida, está inerente a algumas preocupações e sentimentos de ansiedade, relacionadas sobretudo com as actividades de vida diária. Estas preocupações e focos de ansiedade podem resultar de mitos, falta de informação e desenvolvimento de ideias erradas acerca da vida enquanto portador de um dispositivo (BEERY et al., 2002; WOOD & ELLENBOGEN, 2002; WOODRUFF & PRUDENTE, 2005; MALM et al., 2007). O principal foco do desenvolvimento de mitos relacionados com a vida enquanto portadores de dispositivos de pacing e desfibrilhação, está relacionado com a (des)informação fornecida por não profissionais de saúde que integram o circulo social do doente, nomeadamente familiares, vizinhos e outros (BEERY et al., 2002; MALM & HALLBERG, 2006). A equipa de enfermagem do Serviço de Cardiologia do Hospital Fernando Fonseca mantém em funcionamento a consulta de enfermagem ao doente portador de pacemaker e/ou CDI desde há cerca de 18 anos. Nos últimos anos foram sendo realizadas algumas alterações no sentido de melhorar a consulta e os cuidados prestados a estes doentes.

Beyond Wearables : Experiences and Trends in Design of Portable Medical Devices

The use of Portable Medical Devices (PMDs) has become increasingly widespread over the last few years. A combination of factors; including advances in technology, the pressure to reduce public health costs and the desire to make health solutions accessible to a wider patient base are contributing to the growth in the PMD market. Design has a clear role to play in the current and future context of the PMD landscape. In this paper, we identify emerging trends in the design of PMDs; including changes in the form, purpose and mode of use, and explore how these trends are likely to fundamentally impact the nature of healthcare and the patient experience from an experience design perspective. We conclude by identifying a research opportunity for design within the healthcare and PMD context.

Use of personal mobility devices for first-and-last mile travel: The Macquarie-Ryde trial

Electric-motored personal mobility devices (PMDs) are appearing on Australian roads. While legal to import and own, their use is typically illegal for adult riders within the road transport system. However, these devices could provide an answer to traffic congestion by getting people out of cars for short trips (“first-and-last mile” travel). City of Ryde council, Macquarie University, and Transport for NSW examined PMD use within the road transport system. Stage 1 of the project examined PMD use within a controlled pedestrian environment on the Macquarie University campus. Three PMD categories were used: one-wheelers (an electric unicycle, the Solowheel); two-wheelers (an electric scooter, the Egret); and three-wheelers (the Qugo). The two-wheeled PMD was most effective in terms of flexibility. In contrast, the three-wheeled PMD was most effective in terms of speed. One-wheeled PMD riders were very satisfied with their device, especially at speed, but significant training and practice was required. Two-wheeled PMD riders had less difficulty navigating through pedestrian precincts and favoured the manoeuvrability of the device as the relative narrowness of the two-wheeled PMD made it easier to use on a diversity of path widths. The usability of all PMDs was compromised by the weight of the devices, difficulties in ascending steeper gradients, portability, and parking. This was a limited trial, with a small number of participants and within a unique environment. However, agreement has been reached for a Stage 2 extension into the Macquarie Park business precinct for further real-world trials within a fully functional road transport system.

Influencia de diferentes periodos de destete en conejas primiparas en el municipio de Diriamba, Departamento de Carazo, Nicaragua

Este trabajo fue realizado en la Quinta "Myriam", ubicada en el municipio de Diriamba, departamento de Carazo, Nicaragua, propiedad del Dr. Jorge Ferreira. La ubicación geográfica del municipio está comprendida entre los 11° 50' y 12° 00' de Latitud Norte y entre los 86° 00' y 86° 15' de Longitud Oeste, cuenta con una elevación de 551 m.s.n.m., los datos meteorológicos de la zona en los últimos cuatro años (90-93) en cuanto a temperatura, humedad relativa y precipitación promedio fueron: 23.8 °C, 84% y 1184,5 mm respectivamente, (INETER, Departamento de Estadística, 1993). En el presente ensayo, se utilizó un diseño estadístico completamente aleatorizado (DCA), mediante el cual se evaluó el efecto de 3 tratamientos (15, 30 y 45 días de destete) sobre las variables Peso de la Camada al Destete (PCD), Peso de la Madre al Destete (PMD), Peso de la Madre al Segundo Parto (PSP), Ganancia Media Diaria del Parto 1 al Parto 2 (GMDp 1.P2) , con 4 repeticiones por tratamiento, éstas repeticiones estuvieron constituidas por conejas primíparas, las cuales tuvieron un peso que osciló entre 3 - 3.18 kg. y edad homogénea de 7 meses. Las variables fueron sometidas a la prueba de Duncan para determinar la superioridad en rango por tratamiento. Mediante el análisis de varianza se encontró que el efecto de los tratamientos resultó ser altamente significativo sobre la variable Peso de la Camada al Destete (PCD) (P0.01), significativo sobre las variables Peso de la Madre al Segundo Parto (PSP) y Ganancia Media Diaria del Parto 1 al Parto 2 (GMD p 1.P2) (P0.1) y no significativo sobre la variable Peso de la Madre al Destete (PMD) (NS). El efecto de la covariable Peso al Primer Parto (P1P) resultó ser altamente significativo sobre las variables Peso de la Madre al Destete (PMD) y Peso de la Madre al Segundo Parto (PSP) (P0.01). Después de someter las variables a la prueba de DUNCAN se encontraron los siguientes promedios por tratamiento: Peso de la Camada al Destete (PCD) ; T.15 días 1.538 kg P.V.(C), T.30 días 3.360 kg P.V. (B), T.45 días 4.523 kg P.V. (A), Peso de la Madre al Destete (PMD); T.15 días 3.649 kg P.V. (A) T.30 días 3.549 kg P.V. (A), T.45 dias 3.493 kg P.V.(A). Peso de la Madre al Segundo Parto (PSP); T.15 días 3. 449 kg P.V. (B), T.30 días 3.628 kg P.V. (AB), T.45 días 3.777 kg P.V.(A). Ganancia Media Diaria del Parto 1 al Parto 2 (GMD p 1.P2) T .15 días (2.071 g (B), T.30 días 2.718 g (AB), T.45 días 2. 975 g (A). Los promedios y desviaciones standard para las variables Ganancia Media Diaria del Parto 1 al Destete 1 (GMDp1-D1)y Ganancia Media Diaria del Destete l al Parto 2 (GMDD1.P2) por tratamiento fueron: GMD P1-D1; T.l5 días 3.84 g ± 0.50 g, T.30 días 2.54 g ± 0.64 g, T.45 días 2.37 g ± 0.72 g. GMD D1-P2; T.l5 días 2.26 g ± 0.54 g, T.30 días 3.17 g ± 0.74 g, T.45 días 3.93 g ± 0.28 g. Se encontró que el alimento tipo único suministrado a los animales bajo experimentación, cumplió con los requerimientos nutricionales de la especie estudiada. Los costos encontrados por hembra, por tratamiento, fueron C$ 197.21 destete de 15 días, C$ 220.28 destete de 30 días, C$ 243 .1.4 destete de 45 días. Los costos por gazapo destetado fueron de C$ 5.48 destete de 15 días, C$ 6.12 destete de 30 días, C$ 8.10 destete de 45 días.

偏振模色散和时延抖动对啁啾光纤光栅色散补偿特性的影响

对存在偏振模色散(PMD)和群时延(GD)抖动的非理想线性啁啾光纤光栅的色散补偿特性进行了研究。实验测量了啁啾光纤光栅的群时延谱和偏振模色散光谱，理论分析和实验测量表明，啁啾光纤光栅差分群时延(DGD)抖动与其时延抖动密切相关。通过数值模拟方法，计算了线性啁啾光纤光栅偏振模色散眼图代价与入射到啁啾光纤光栅色散补偿器的光信号的偏振方向的关系，计算结果表明在使用啁啾光纤光栅色散补偿器时应对光信号的偏振方向进行调整，以获得最佳补偿效果。另外结合实验数据，模拟计算并讨论了非理想线性啁啾光纤光栅群时延抖动和偏振模色