12,568 research outputs found
Effect of photoperiod and host distribution on the horizontal transmission of Isaria fumosorosea (Hypocreales: Cordycipitaceae) in greenhouse whitefly assessed using a novel model bioassay
A model bioassay was used to evaluate the epizootic potential and determine the horizontal transmission efficiency of Isaria fumosorosea Trinidadian strains against Trialeurodes vaporariorum pharate adults under optimum conditions (25±0.5°C, ~100% RH) at two different photoperiods. Untreated pharate adults were arranged on laminated graph paper at different distributions to simulate varying infestation levels on a leaf surface. Four potential hosts were located 7, 14 and 21 mm away from a central sporulating cadaver simulating high, medium and low infestation levels, respectively. Percent hosts colonized were recorded 7, 12, 14 and 21 days post-treatment during a 16- and 24-h photophase. After 21 days, mean percent hosts colonized at the highest, middle and lowest infestation levels were 93 and 100%, 22 and 58%, 25 and 39% under a 16- and 24-h photophase, respectively. From the results, it was concluded that the longer the photophase, the greater the percentage of hosts colonized, and as host distance increased from the central sporulating cadaver, colonization decreased. The use of this novel model bioassay technique is the first attempt to evaluate the epizootic potential and determine the horizontal transmission efficiency of I. fumosorosea Trinidadian strains under optimal environmental conditions at different photoperiods. This bioassay can be used to assess horizontal transmission efficiency for the selection of fungi being considered for commercial biopesticide development
Methods for assessing the contribution of renewable technologies to energy security: the electricity sector of Fiji
In recent years, renewable energy technologies have been advocated in Fiji on the basis that they improve energy security and serve as a risk-mitigation measure against oil price volatility. Despite this, there have been no published attempts to measure the impact of renewable technologies on energy security or to assess the major threats to that security. This analysis is important if the benefits of renewable energy sources in Fiji are to be evaluated adequately. This article considers the key threats to the security of electricity supply in Fiji for grid-connected and off-grid areas and uses these as a basis for a definition of energy security that is relevant to Fiji. It proposes a method for assessing the potential contribution of renewable technologies to the security of electricity supply in Fiji, based on mean-variance portfolio theory used in financial markets
The added value of implementing the Planet Game scenario with Collage and Gridcole
This paper discusses the suitability and the added value of Collage and Gridcole when contrasted with other solutions participating in the ICALT 2006 workshop titled “Comparing educational modelling languages on a case study.” In this workshop each proposed solution was challenged to implement a Computer-Supported Collaborative Learning situation (CSCL) posed by the workshop’s organizers. Collage is a pattern-based authoring tool for the creation of CSCL scripts compliant with IMS Learning Design (IMS LD). These IMS LD scripts can be enacted by the Gridcole tailorable CSCL system. The analysis presented in the paper is organized as a case study which considers the data recorded in the workshop discussion as well the information reported in the workshop contributions. The results of this analysis show how Collage and Gridcole succeed in implementing the scenario and also point out some significant advantages in terms of design reusability and generality, user-friendliness, and enactment flexibility
Tensor Analysis and Fusion of Multimodal Brain Images
Current high-throughput data acquisition technologies probe dynamical systems
with different imaging modalities, generating massive data sets at different
spatial and temporal resolutions posing challenging problems in multimodal data
fusion. A case in point is the attempt to parse out the brain structures and
networks that underpin human cognitive processes by analysis of different
neuroimaging modalities (functional MRI, EEG, NIRS etc.). We emphasize that the
multimodal, multi-scale nature of neuroimaging data is well reflected by a
multi-way (tensor) structure where the underlying processes can be summarized
by a relatively small number of components or "atoms". We introduce
Markov-Penrose diagrams - an integration of Bayesian DAG and tensor network
notation in order to analyze these models. These diagrams not only clarify
matrix and tensor EEG and fMRI time/frequency analysis and inverse problems,
but also help understand multimodal fusion via Multiway Partial Least Squares
and Coupled Matrix-Tensor Factorization. We show here, for the first time, that
Granger causal analysis of brain networks is a tensor regression problem, thus
allowing the atomic decomposition of brain networks. Analysis of EEG and fMRI
recordings shows the potential of the methods and suggests their use in other
scientific domains.Comment: 23 pages, 15 figures, submitted to Proceedings of the IEE
Determination of pressure coefficient for a high-rise building with atypical ground plan
In this article, the results of pressure coefficient on the atypical object obtained by experimental measurements in a boundary layer wind tunnel (BLWT) of Slovak University of Technology in Bratislava (STU) and computational fluid dynamics simulation (CFD) are presented. The pressure coefficient is one of the most important parameters expressing the wind pressure distribution on the structure. The loading by wind can only be acquired by execution of detailed tests and numerical analyses [1].Web of Science14214513
The Sloan Digital Sky Survey Stripe 82 Imaging Data: Depth-Optimized Co-adds Over 300 Deg^2 in Five Filters
We present and release co-added images of the Sloan Digital Sky Survey (SDSS)
Stripe 82. Stripe 82 covers an area of 300 deg^2 on the Celestial Equator, and
has been repeatedly scanned 70-90 times in the ugriz bands by the SDSS imaging
survey. By making use of all available data in the SDSS archive, our co-added
images are optimized for depth. Input single-epoch frames were properly
processed and weighted based on seeing, sky transparency, and background noise
before co-addition. The resultant products are co-added science images and
their associated weight images that record relative weights at individual
pixels. The depths of the co-adds, measured as the 5 sigma detection limits of
the aperture (3.2 arcsec diameter) magnitudes for point sources, are roughly
23.9, 25.1, 24.6, 24.1, and 22.8 AB magnitudes in the five bands, respectively.
They are 1.9-2.2 mag deeper than the best SDSS single-epoch data. The co-added
images have good image quality, with an average point-spread function FWHM of
~1 arcsec in the r, i, and z bands. We also release object catalogs that were
made with SExtractor. These co-added products have many potential uses for
studies of galaxies, quasars, and Galactic structure. We further present and
release near-IR J-band images that cover ~90 deg^2 of Stripe 82. These images
were obtained using the NEWFIRM camera on the NOAO 4-m Mayall telescope, and
have a depth of about 20.0--20.5 Vega magnitudes (also 5 sigma detection limits
for point sources).Comment: 19 pages, 17 figures, accepted for publication in ApJ
- …