Female entrepreneurship

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Patellarsehne versus Semitendinosus-/Gracilis-Sehne als Ersatz zur Rekonstruktion des vorderen Kreuzbandes:5-Jahres-Ergebnisse eines randomisierten Patientenkollektivs ; eine klinische Studie

Ziel/Methode: Vergleich von 5-Jahres-Ergebnissen vorderer Kreuzbandplastiken mit Patellarsehne (PS) bzw. Semitendinosus-/Gracilissehne (S/GS). 29 Patienten: 14 mit PS-Ersatz und 15 mit S/GS-Ersatz. Datenerhebung mit IKDC-Knie-Evaluationsblatt (IKDC), Lysholm-Score, Tegner-Aktivitäts-Score (TAS) und KT-1000-Arthrometer. Ergebnisse: IKDC: PS-Gruppe 78,6% ”normal“ und ”fast normal“; S/GS-Gruppe: 80% ”normal“ und ”fast normal“ (p=0,949). Lysholm: PS-Gruppe 88,86 Punkte und S/GS-Gruppe 90,27 Punkte (p=0,88). TAS: PS-Gruppe 5,64 Punkte und S/GS-Gruppe 5,53 Punkte (p=0,847). KT-1000: PS-Gruppe 1,64 mm und S/GS-Gruppe 0,67 mm Seitendifferenz (p=0,217). Fazit: Beide Transplantate zeigen gute bis sehr gute Ergebnisse, keines ist überlegen

Humped-back shaped response of plant species richness to increasing shrub encroachment in calcareous grasslands

In the present study, we examined the effect of shrub encroachment in temperate semi-natural grasslands on plant species diversity. We tested the hypothesis that an initial shrub encroachment leads to enhanced habitat heterogeneity and thereby to a higher diversity. In a calcareous grassland near Göttingen (Germany) we analysed the effect of shrub encroachment on the species richness in 30, 100 m2 plots each with 10 subplots of 1m2 size. The 30 main plots belonged to six different shrub encroachment classes. A descriptive correlative gradient analysis of shrub invaded grasslands and their species number of flowering plants was performed. Within the 30 plots of different shrub encroachment a total of 203 plant species were recorded. The mean α1-diversity (level of subplots), mean α2-diversity (level of plots) as well as the α3-diversity (level of shrub encroachment classes) have their highest values at medium shrub invaded sites. This finding is in line with our hypothesis of a hump-back relation between shrub encroachment and species richness, and can be explained by the increased habitat heterogeneity. However, Detrended Correspondence Analysis (DCA) emphasized the importance of the present vegetation composition for species richness. The dominance of highly competitive, clonal-growing grass species is accompanied by low diversity swards with a lower facilitation of shrub establishment. Species accumulation curves highlight the benefit of shrub encroachment for γ-(landscape-) diversity. This result emphasises the importance of habitat heterogeneity for biodiversity and, therefore, nature conservation

DECENTRALIZED APPROACHES TO ADAPTIVE TRAFFIC CONTROL AND AN EXTENDED LEVEL OF SERVICE CONCEPT

Traffic systems are highly complex multi-component systems suffering from instabilities and non-linear dynamics, including chaos. This is caused by the non-linearity of interactions, delays, and fluctuations, which can trigger phenomena such as stop-and-go waves, noise-induced breakdowns, or slower-is-faster effects. The recently upcoming information and communication technologies (ICT) promise new solutions leading from the classical, centralized control to decentralized approaches in the sense of collective (swarm) intelligence and ad hoc networks. An interesting application field is adaptive, self-organized traffic control in urban road networks. We present control principles that allow one to reach a self-organized synchronization of traffic lights. Furthermore, vehicles will become automatic traffic state detection, data management, and communication centers when forming ad hoc networks through inter-vehicle communication (IVC). We discuss the mechanisms and the efficiency of message propagation on freeways by short-range communication. Our main focus is on future adaptive cruise control systems (ACC), which will not only increase the comfort and safety of car passengers, but also enhance the stability of traffic flows and the capacity of the road (“traffic assistance”). We present an automated driving strategy that adapts the operation mode of an ACC system to the autonomously detected, local traffic situation. The impact on the traffic dynamics is investigated by means of a multi-lane microscopic traffic simulation. The simulation scenarios illustrate the efficiency of the proposed driving strategy. Already an ACC equipment level of 10% improves the traffic flow quality and reduces the travel times for the drivers drastically due to delaying or preventing a breakdown of the traffic flow. For the evaluation of the resulting traffic quality, we have recently developed an extended level of service concept (ELOS). We demonstrate our concept on the basis of travel times as the most important variable for a user-oriented quality of service

Autonomous detection and anticipation of jam fronts from messages propagated by inter-vehicle communication

In this paper, a minimalist, completely distributed freeway traffic information system is introduced. It involves an autonomous, vehicle-based jam front detection, the information transmission via inter-vehicle communication, and the forecast of the spatial position of jam fronts by reconstructing the spatiotemporal traffic situation based on the transmitted information. The whole system is simulated with an integrated traffic simulator, that is based on a realistic microscopic traffic model for longitudinal movements and lane changes. The function of its communication module has been explicitly validated by comparing the simulation results with analytical calculations. By means of simulations, we show that the algorithms for a congestion-front recognition, message transmission, and processing predict reliably the existence and position of jam fronts for vehicle equipment rates as low as 3%. A reliable mode of operation already for small market penetrations is crucial for the successful introduction of inter-vehicle communication. The short-term prediction of jam fronts is not only useful for the driver, but is essential for enhancing road safety and road capacity by intelligent adaptive cruise control systems.Comment: Published in the Proceedings of the Annual Meeting of the Transportation Research Board 200

Calibrating Car-Following Models using Trajectory Data: Methodological Study

The car-following behavior of individual drivers in real city traffic is studied on the basis of (publicly available) trajectory datasets recorded by a vehicle equipped with an radar sensor. By means of a nonlinear optimization procedure based on a genetic algorithm, we calibrate the Intelligent Driver Model and the Velocity Difference Model by minimizing the deviations between the observed driving dynamics and the simulated trajectory when following the same leading vehicle. The reliability and robustness of the nonlinear fits are assessed by applying different optimization criteria, i.e., different measures for the deviations between two trajectories. The obtained errors are in the range between~11% and~29% which is consistent with typical error ranges obtained in previous studies. In addition, we found that the calibrated parameter values of the Velocity Difference Model strongly depend on the optimization criterion, while the Intelligent Driver Model is more robust in this respect. By applying an explicit delay to the model input, we investigated the influence of a reaction time. Remarkably, we found a negligible influence of the reaction time indicating that drivers compensate for their reaction time by anticipation. Furthermore, the parameter sets calibrated to a certain trajectory are applied to the other trajectories allowing for model validation. The results indicate that ``intra-driver variability'' rather than ``inter-driver variability'' accounts for a large part of the calibration errors. The results are used to suggest some criteria towards a benchmarking of car-following models

Idiopathic Adolescent Scoliosis and self-concept

Introducción y objetivos. Esta investigación trata sobre adolescentes que presentan escoliosis idiopática. Queremos estudiar si la manifestación de tal patología tiene efectos psicológicos en el adolescente que la presenta y sobre todo en la imagen que percibe de sí mismo como de su entorno. El objetivo del presente estudio se concreta en conocer la influencia de la escoliosis idiopática en el autoconcepto o imagen de si mismo en el adolescente. Material y métodos. Estudio observacional. Muestra formada por 17 adolescentes de 10-18 años de edad. En primer lugar, al tratarse de menores de edad y con el fin de informar de las características del estudio, como de la participación en el mismo, se le pasó un consentimiento informado a los padres o tutores. Asimismo, se extrajeron una serie de datos biográficos para identificar aspectos como el perfil clínico y personal, diagnóstico, antecedentes familiares, datos personal y de ocio del paciente, a través de un cuestionario de datos biográficos. Finalmente se le pasó el cuestionario de Pierre-Harris que consta de 80 ítems que abarcan las siguientes dimensiones del concepto de si mismo: comportamiento, estatus general y académico, popularidad, felicidad y satisfacción, apariencia física, ansiedad. Tras la recogida de los datos, se realizó un análisis de distribución de frecuencias, mediante el método estadístico SPSS v. 15.0 para Windows, con el cálculo de la media y la desviación típica, de los mismos. Resultados. Las puntuaciones del cuestionario de Pierre-Harris por cada sujeto, están por encima de la media establecida en cada dimensión. Solamente, en la dimensión de ansiedad, hay 5 sujetos por debajo de la media. Conclusiones. No se observó una imagen de sí mismo negativa o por debajo de la media en la muestra estudiada en ninguna dimensión del cuestionario. Solamente una de las dimensiones presentaba algunos individuos por debajo, por lo tanto, en la muestra estudiada con escoliosis idiopática del adolescente, la imagen de sí mismo es buena, por los valores encontrados.Terapia y Rehabilitació

Simple and selective spectrophotometric assay of diethylcarbamazine citrate using 2,3-dichloro-5,6-dicyano-p-benzoquinone and 2,4-dinitro phenol

Two simple, rapid and inexpensive spectrophotometric methods are described for the determination of diethylcarbamazine citrate (DEC) in bulk drug and formulations. The methods are based on the charge-transfer (CT) complexation reaction involving DEC as the n- donor and 2,3-dichloro-5,6-dicyano-p-benzoquinone DDQ] (method A) and 2,4-dinitro phenol DNP] (method B) as pi-acceptors in chloroform. The absorbance of CT complexes was measured at 480 nm for method A, and 420 nm for method B. Under optimum conditions, Beer's law was obeyed over the concentration ranges 4-90 and 4-100 mu g mL(-1) for methods A and B, respectively

Reducing congestion in obstructed highways with traffic data dissemination using adhoc vehicular networks

Vehicle-to-vehicle communications can be used effectively for intelligent transport systems (ITSs) and location-aware services. The ability to disseminate information in an ad hoc fashion allows pertinent information to propagate faster through a network. In the realm of ITS, the ability to spread warning information faster and further is of great advantage to receivers. In this paper we propose and present a message-dissemination procedure that uses vehicular wireless protocols to influence vehicular flow, reducing congestion in road networks. The computational experiments we present show how a car-following model and lane-change algorithm can be adapted to “react” to the reception of information. This model also illustrates the advantages of coupling together with vehicular flow modelling tools and network simulation tools