Topological Measure Locating the Effective Crossover between Segregation and Integration in a Modular Network

We introduce an easily computable topological measure which locates the effective crossover between segregation and integration in a modular network. Segregation corresponds to the degree of network modularity, while integration is expressed in terms of the algebraic connectivity of an associated hyper-graph. The rigorous treatment of the simplified case of cliques of equal size that are gradually rewired until they become completely merged, allows us to show that this topological crossover can be made to coincide with a dynamical crossover from cluster to global synchronization of a system of coupled phase oscillators. The dynamical crossover is signaled by a peak in the product of the measures of intra-cluster and global synchronization, which we propose as a dynamical measure of complexity. This quantity is much easier to compute than the entropy (of the average frequencies of the oscillators), and displays a behavior which closely mimics that of the dynamical complexity index based on the latter. The proposed toplogical measure simultaneously provides information on the dynamical behavior, sheds light on the interplay between modularity vs total integration and shows how this affects the capability of the network to perform both local and distributed dynamical tasks

An RF excited plasma cathode electron beam gun design

A plasma cathode electron beam (EB) gun is presented in this work. A radio frequency (RF) excited plasma at 84 MHz was used as the electron source to produce a beam power of up to 3.2 kW at -60 kV accelerating voltage. The pressure in the plasma chamber is approximately 1 mbar. The electrons are extracted from the plasma chamber to the vacuum chamber (at 10-5 mbar) through a diaphragm with a 0.5 mm diameter nozzle. Advantages over thermionic cathode guns were demonstrated empirically. Maintenance costs are reduced, as the cathode does not wear out as quickly during use. RF modulation can be used for controlling the beam power and thus there is no requirement for a grid cup electrode. Rapid (sub 1 microsecond) beam pulsing is achievable. Optical emission spectroscopy has been used to study the plasma parameters that affect the level of beam current

Characterisation of an RF excited argon plasma cathode electron beam gun

This work describes the experimental set up used for carrying out spectroscopic measurements in a plasma cathode electron beam (EB) gun. Advantages of plasma cathode guns over thermionic guns are described. The factors affecting electron beam power such as plasma pressure, excitation power and plasma chamber geometry are discussed. The maximum beam current extracted was 53 mA from a 0.5 mm diameter aperture in the plasma chamber. In this work, the electron source is an argon plasma excited at 84 MHz. The pressure in the plasma chamber was measured to be within 0.9 to 1.2 mbar and was controlled by varying gas flow rates. The vacuum chamber was at a pressure of 10^-5 mbar.TWI and Brunel University

Biological Fixation of N2 in Mono and Polyspecific Legume Pasture in the Humid Mediterranean Zone of Chile

del Pozo, A (del Pozo, Alejandro). Univ Talca, Fac Ciencias Agr, Talca, ChileDespite annual legume pasture are of great importance for dryland agricultural systems in Mediterranean environments, there are few studies of N-2 biological fixation (NBF) reported in Chile. In this study the NBF of four annual legume species: subterranean clover (Trifolium subterraneum L.), yellow serradella (Ornithopus compressus L.), arrow-leaf clover (T. vesiculosum L.), and crimson clover (T. incarnatum L.) (Experiment 1), as well as seven mixtures of these species (Experiment 2) were assessed. The NBF was measured by the N-15 natural abundance technique. The objective was to determine NBF in the legume species and in distinct mixtures used. The study was carried out in an Andisol of the Andean Precordillera located in the humid Mediterranean zone of Chile. Pasture was evaluated for biomass; and total N and natural abundance of N-15 were analyzed in plant material samples. In Experiment 1 (monospecific legume species pasture), N derived from fixation ranged between 43 and 147 kg N ha(-1) and where T. vesiculosum and T. subterraneum presented statistical differences (P <= 0.05) in connection with the other species. In the legume mixtures (Experiment 2), N derived by fixation varied between 97 and 214 kg N ha(-1) where the 50-50 mixtures (T. subterraneum and O. compressus, or T. subterraneum and T. vesiculosum, respectively) had the highest N fixation. Fixed N ranged between 12 and 25 kg N t(-1) DM, showing significant differences among mono and polyspecific legume species

Diseño y Simulación Mecánica de un Actuador Hidráulico Rotativo Sumergible Para Aplicación en Hidroterapia/Design and Mechanical Simulation of a Submersible Rotary Hydraulic Actuator for Hydrotherapy Application

El presente trabajo demuestra el proceso en la investigación inicial para el desarrollo de un actuador giratorio hidráulico para fines terapéuticos. El dispositivo se basa en la necesidad de un aparato motor aplicable a la rehabilitación de lesiones de rodilla, con la capacidad de ser usado en la hidroterapia, para lo cual se realiza una revisión bibliográfica y se define el comportamiento del actuador en función a los fenómenos de presión y flujo, definiendo así las funciones para el par y la velocidad del actuador. En una primera etapa, se presenta un modelo simplificado del actuador, para luego simular el comportamiento mecánico de los componentes con la ayuda de un software de análisis de elementos finitos. Concluyendo con la validación de los elementos principales del actuador, llamados eje y aleta, sometidos a los parámetros delimitados para la aplicación, dejando la base de un modelo del mecanismo útil para el cálculo de la dinámica del sistema como siguiente paso de la investigación. The present work demonstrates the process in the research and development of a hydraulic rotary actuator for therapeutic purposes. The device is based on the need for a motor apparatus applicable to the rehabilitation of knee injuries, with the ability to be used in hydrotherapy, for which a literature review is performed and the behavior of the actuator is defined depending on the pressure and flow phenomena, thus defining the functions for the torque and speed of the actuator. In the first stage, a simplified model of the actuator is presented, to proceed to simulate the mechanical behavior of the components with the help of finite element analysis software. Concluding with the validation of the main elements of the actuator, called axis and fin, subject to the parameters defined for the application, leaving the basis of a model of the mechanism useful for calculating the dynamics of the system as the next step of the investigation. Palabras claves: Actuador rotatorio, Simulación, Diseño, Mecánica hidráulica. Keywords: Rotary actuator, Simulation, Design, Hydraulic Mechanics

The Effect of Nitrogen Fertilisation on the Morphological Development and Growth Rate of Star Grass (\u3cem\u3eCynodon nlemfuensis\u3c/em\u3e)

Nitrogen is one of the main inputs used in forage production systems to increase productivity. However, in Cuba, the availability of fertiliser N is limited and therefore if applied, needs to be used with high efficiency. Previous studies (Johnson, 2001, Del Pozo, 2003) investigated the effects of N on growth, carbohydrate and protein content but did not consider morphological changes in Cynodon nlemfuensis. A study was therefore undertaken investigating how N application influences morphological development of the plant and how these changes might affect the efficiency of use of applied N

Death, dying and informatics: misrepresenting religion on MedLine

BACKGROUND: The globalization of medical science carries for doctors worldwide a correlative duty to deepen their understanding of patients' cultural contexts and religious backgrounds, in order to satisfy each as a unique individual. To become better informed, practitioners may turn to MedLine, but it is unclear whether the information found there is an accurate representation of culture and religion. To test MedLine's representation of this field, we chose the topic of death and dying in the three major monotheistic religions. METHODS: We searched MedLine using PubMed in order to retrieve and thematically analyze full-length scholarly journal papers or case reports dealing with religious traditions and end-of-life care. Our search consisted of a string of words that included the most common denominations of the three religions, the standard heading terms used by the National Reference Center for Bioethics Literature (NRCBL), and the Medical Subject Headings (MeSH) used by the National Library of Medicine. Eligible articles were limited to English-language papers with an abstract. RESULTS: We found that while a bibliographic search in MedLine on this topic produced instant results and some valuable literature, the aggregate reflected a selection bias. American writers were over-represented given the global prevalence of these religious traditions. Denominationally affiliated authors predominated in representing the Christian traditions. The Islamic tradition was under-represented. CONCLUSION: MedLine's capability to identify the most current, reliable and accurate information about purely scientific topics should not be assumed to be the same case when considering the interface of religion, culture and end-of-life care