1,480 research outputs found
Report dose-to-medium in clinical trials where available; A consensus from the Global Harmonisation Group to maximize consistency
PURPOSE: To promote consistency in clinical trials by recommending a uniform framework as it relates to radiation transport and dose calculation in water versus in medium.
METHODS: The Global Quality Assurance of Radiation Therapy Clinical Trials Harmonisation Group (GHG; www.rtqaharmonization.org) compared the differences between dose to water in water (D
RESULTS: No framework was found to be ideal or perfect given the history, complexity, and current status of radiation therapy. Nevertheless, based on the evidence available, the GHG established a recommendation preferring dose to medium in medium (D
CONCLUSIONS: Dose to medium in medium (
Discovering predictive variables when evolving cognitive models
A non-dominated sorting genetic algorithm is used to evolve models of learning from different theories for multiple tasks. Correlation analysis is performed to identify parameters which affect performance on specific tasks; these are the predictive variables. Mutation is biased so that changes to parameter values tend to preserve values within the population's current range. Experimental results show that optimal models are evolved, and also that uncovering predictive variables is beneficial in improving the rate of convergence
Seeds Buffering for Information Spreading Processes
Seeding strategies for influence maximization in social networks have been
studied for more than a decade. They have mainly relied on the activation of
all resources (seeds) simultaneously in the beginning; yet, it has been shown
that sequential seeding strategies are commonly better. This research focuses
on studying sequential seeding with buffering, which is an extension to basic
sequential seeding concept. The proposed method avoids choosing nodes that will
be activated through the natural diffusion process, which is leading to better
use of the budget for activating seed nodes in the social influence process.
This approach was compared with sequential seeding without buffering and single
stage seeding. The results on both real and artificial social networks confirm
that the buffer-based consecutive seeding is a good trade-off between the final
coverage and the time to reach it. It performs significantly better than its
rivals for a fixed budget. The gain is obtained by dynamic rankings and the
ability to detect network areas with nodes that are not yet activated and have
high potential of activating their neighbours.Comment: Jankowski, J., Br\'odka, P., Michalski, R., & Kazienko, P. (2017,
September). Seeds Buffering for Information Spreading Processes. In
International Conference on Social Informatics (pp. 628-641). Springe
Riqueza e composição de vertebrados em latrinas ativas e inativas de Pteronura brasiliensis (Carnivora, Mustelidae) na Amazônia Oriental, Brasil
This study aimed to evaluate the richness and composition of the medium and large sized vertebrates in active and inactive latrines of Giant otters [Pteronura brasiliensis (Gmelin, 1788)] in a Sustainable Use conservation unit in the Eastern Brazilian Amazon. The study was performed in 45 latrines along 230 km of the Falsino and Araguari rivers (0°55'N, 51°35'W) and from this total, 24 presented fresh feces of Giant otters while 21 presented only old feces. From July to November 2012 each latrine was continuously monitored with a camera trap set to operate for 24 hours. The effort resulted in 458.8 camera trap/days, with 247.5 camera trap/days in latrines with fresh feces and 211.3 camera trap/ days with old feces. From this effort we obtained photos from a total of 22 vertebrate species. Most species photographed at latrines were mammals (n = 13), followed by birds (n = 6) and reptiles (n = 3). The most frequently photographed species were paca [Cuniculus paca (Linnaeus, 1766), n = 21], ocelot [Leopardus pardalis (Linnaeus, 1758), n = 11], white-tipped dove (Leptotila verreauxi Bonaparte, 1855, n = 8), giant otter [Pteronura brasiliensis (Gmelin, 1788), n = 7], and tapir [Tapirus terrestris (Linnaeus, 1758), n = 6], that accounted for 55.8% of all records. Most records (69.5%) were obtained in latrines with fresh feces and the number of vertebrate species was greater (n = 19) than in latrines with old feces (n = 15). However, the dissimilarity between the vertebrate communities of latrines with fresh and old feces did not differ statistically. However, the mean visitation of vertebrates to latrines with fresh feces was slightly higher than with old feces, although this difference was only marginally significant. There was an increase in records of felids [Leopardus pardalis, Leopardus wiedii (Schinz, 1821), and Panthera onca (Linnaeus, 1758)] in latrines with old feces, but it was only marginally significant. Thus, the presence of fresh feces of giant otters seems to increase the records of vertebrates, being especially important for groups with similar trophic guild
Analysis of Finite Microstrip Structures Using an Efficient Implementation of the Integral Equation Technique
An efficient numerical implementation of the Integral Equation technique (IE) has
been developed for the analysis of the electrical characteristics of finite microstrip structures.
The technique formulates a volume version of the IE for the finite dielectric objects, and a
standard surface IE technique for the metallic areas. The system of integral equations formu-
lated are solved with special numerical techniques described in this paper. The input impedances
of several microstrip antennas have been computed, showing good agreement with respect mea-
surements. The technique has shown to be accurate even for complex geometries containing
several stacked dielectric layers. The radiation patterns of the structures have also been com-
puted, and measured results from real manufactured hardware confirm that backside radiation
and secondary lobes are accurately predicted by the theoretical model. The paper also discuss
a suitable excitation model for finite size ground planes, and investigates the possibilities for
an independent meshing of the metallic areas and the dielectric objects inside a given geom-
etry. The practical value of the approach derived is that microstrip circuits can be designed
minimizing the volume and size of the dielectric substrates.This work has been supported bythe Spanish National Project ESP2001-4546-PE, and RegionalSeneca Project PB/4/FS/02
A Deep Sequencing Approach to Comparatively Analyze the Transcriptome of Lifecycle Stages of the Filarial Worm, Brugia malayi
Lymphatic filariasis, also known as elephantiasis, is a tropical disease affecting over 120 million people worldwide. More than 40 million people live with painful, disfiguring symptoms that can cause severe debilitation and social stigma. The disease is caused by infection with thread-like filarial nematodes (roundworms) that have a complex parasitic lifecycle involving both human and mosquito hosts. In the study, the authors profiled the transcriptome (the set of genes transcribed into messenger RNA rather than all of those in the genome) of the human filarial worm Brugia malayi in different lifecyle stages using deep sequencing technology. The analysis revealed major transitions in RNA expression from eggs through larval stages to adults. Using statistical approaches, the authors identified groups of genes with distinct life stage dependent transcriptional patterns, with particular emphasis on genes displaying sex-biased or germline-enriched patterns and those displaying significant changes during larval development. This study presents a first comprehensive analysis of the lifecycle transcriptome of B. malayi, providing fundamental molecular information that should help researchers better understand parasite biology and could provide clues for the development of more effective interventions
Sequestration of Martian CO2 by mineral carbonation
Carbonation is the water-mediated replacement of silicate minerals, such as olivine, by carbonate, and is commonplace in the Earth’s crust. This reaction can remove significant quantities of CO2 from the atmosphere and store it over geological timescales. Here we present the first direct evidence for CO2 sequestration and storage on Mars by mineral carbonation. Electron beam imaging and analysis show that olivine and a plagioclase feldspar-rich mesostasis in the Lafayette meteorite have been replaced by carbonate. The susceptibility of olivine to replacement was enhanced by the presence of smectite veins along which CO2-rich fluids gained access to grain interiors. Lafayette was partially carbonated during the Amazonian, when liquid water was available intermittently and atmospheric CO2 concentrations were close to their present-day values. Earlier in Mars’ history, when the planet had a much thicker atmosphere and an active hydrosphere, carbonation is likely to have been an effective mechanism for sequestration of CO2
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