4,142 research outputs found
Self-management of context-aware overlay ambient networks
Ambient Networks (ANs) are dynamically changing and heterogeneous as they consist of potentially large numbers of independent, heterogeneous mobile nodes, with spontaneous topologies that can logically interact with each other to share a common control space, known as the Ambient Control Space. ANs are also flexible i.e. they can compose and decompose dynamically and automatically, for supporting the deployment of cross-domain (new) services. Thus, the AN architecture must be sophisticatedly designed to support such high level of dynamicity, heterogeneity and flexibility. We advocate the use of service specific overlay networks in ANs, that are created on-demand according to specific service requirements, to deliver, and to automatically adapt services to the dynamically changing user and network context. This paper presents a self-management approach to create, configure, adapt, contextualise, and finally teardown service specific overlay networks
Velocity fluctuations and population distribution in clusters of settling particles at low Reynolds number
A study on the spatial organization and velocity fluctuations of non Brownian
spherical particles settling at low Reynolds number in a vertical Hele-Shaw
cell is reported. The particle volume fraction ranged from 0.005 to 0.05, while
the distance between cell plates ranged from 5 to 15 times the particle radius.
Particle tracking revealed that particles were not uniformly distributed in
space but assembled in transient settling clusters. The population distribution
of these clusters followed an exponential law. The measured velocity
fluctuations are in agreement with that predicted theoretically for spherical
clusters, from the balance between the apparent weight and the drag force. This
result suggests that particle clustering, more than a spatial distribution of
particles derived from random and independent events, is at the origin of the
velocity fluctuations.Comment: 13 pages, 8 figure
Hippocampal Infusion of Zeta Inhibitory Peptide Impairs Recent, but Not Remote, Recognition Memory in Rats.
Spatial memory in rodents can be erased following the infusion of zeta inhibitory peptide (ZIP) into the dorsal hippocampus via indwelling guide cannulas. It is believed that ZIP impairs spatial memory by reversing established late-phase long-term potentiation (LTP). However, it is unclear whether other forms of hippocampus-dependent memory, such as recognition memory, are also supported by hippocampal LTP. In the current study, we tested recognition memory in rats following hippocampal ZIP infusion. In order to combat the limited targeting of infusions via cannula, we implemented a stereotaxic approach for infusing ZIP throughout the dorsal, intermediate, and ventral hippocampus. Rats infused with ZIP 3-7 days after training on the novel object recognition task exhibited impaired object recognition memory compared to control rats (those infused with aCSF). In contrast, rats infused with ZIP 1 month after training performed similar to control rats. The ability to form new memories after ZIP infusions remained intact. We suggest that enhanced recognition memory for recent events is supported by hippocampal LTP, which can be reversed by hippocampal ZIP infusion
Identification Of Potential Entomopathogenic Fungi Of Tetranychus Kanzawai Kishida (Tetranychidae: Acarina) Using Its-5.8s Rdna Region AS Molecular Marker
Fungi has been tested as one of the potential control agents for insect pests, which raises hopes for developing fungi as good biopesticides. The high variation within fungi species made taxonomic identification procedures more complex, thus molecular identification techniques are needed in addition to traditional morphological characteristics currently used as primary methods to classify fungi species. The objective of this research was to identify the species of the most pathogenic fungi to Tetranychus kanzawai Kishida using RAPD-PCR. The internal transcribed spacer of 5.8s rDNA (ITS-5.8s rDNA) sequence of these fungal isolates were amplified using two sets of universal primers for ITS and then analyzed. Molecular identification showed that these isolates had a higher of similarity to Metarhizium anisopliae than Metarhizium flavoviride
Toward the Development of a Global Financial Safety Net or a Segmentation of the Global Financial Architecture?
This article examines the prospects for the development of a comprehensive global financial safety net (GFSN). It discusses the optimal layout of the GFSN, comprising the International Monetary Fund, regional financing arrangements (RFAs), as well as bilateral or multilateral central bank swap arrangements, and the relationship between these. It then briefly reviews and appraises the current structure and functioning of these different layers of the GFSN and discusses the need and scope for strengthening cooperation between RFAs and the IMF. It argues that the GFSN is still very patchy and there is little reason to expect significant progress in better collaboration between RFAs and the IMF as long as the latter’s governance structure is not significantly revamped. Indeed, risks are that the GFSN will become even more fragmented with the further development of the European Stability Mechanism and the emergence of the BRICS Contingent Reserve Arrangement. To prevent a further fragmentation of the GFSN, substantial governance reform of the IMF is urgently needed
Avaliação do incremento em volume de madeira de Quassia amara L.- Simaroubaceae, em cultivo agroecológico no trópico úmido da Costa Rica.
Quassia amara é arbusto de 3 a 6 metros de altura, tendo sido retirado indiscriminadamente das florestas para extrair do caule as quassinas usadas na indústria farmacêutica e como inseticida em agricultura orgânica. Não se tem muita informação técnica acerca do crescimento desta espécie para subsidiar estratégias de manejo sustentado. Este trabalho tem como objetivo avaliar o crescimento de Q. amara L. em cultivo agroecológico na Costa Rica. O trabalho consistiu em realizar avaliações do desenvolvimento de indivíduos de Q. amara em parcelas permanentes de medições, instaladas em meio às plantações desta espécie em consórcio com essências arbóreas. Foram efetuadas medições de diâmetro do caule a 10 cm do solo e altura total. Foi observado que em função das taxas de crescimento vegetal e incrementos médio e corrente anuais (IMA e ICA), mesmo após cinco anos de plantio, a madeira de Quassia amara para extração de quassinas não está pronta para colheita
New Periodontal Pathogens and their Biogeography in ex Vivo Biofilms
Background: About 35% of the oral microbiome remains uncultured due to limitations of conventional laboratory techniques. More than 200 of those phylotypes have been catalogued in the HOMD and a subset of them had been proposed as candidate periodontal pathogens. This segment of the microbiome merits further investigation, as it might harbor important pathogens that are currently overlooked. Objective: The objective of this study was to devise an imaging approach to study such phylotypes in the conditions most conducive to their growth and begin to unveil their ecological and biogeographical characteristics.
Methods: Previous work from the Teles Lab had identified the most common candidate periodontal pathogenic phylotypes and developed biofilms that fostered their growth. Such biofilms and their spent media were used for the development of the imaging approach. 16S rRNA sequencing data from 18 ex vivo biofilms developed from samples collected from 16 periodontitis patients were screened to determine the most common phylotypes. Given the unculturability of phylotypes, pure and mixed cultures of reference strains (Actinomyces israelii, Porphyromonas gingivalisand Fusobacterium nucleatum) were used to develop the method. Specific and eubacterial probes targeting 16S rRNA of the taxa of interest were synthesized and tested on pure and mixed cultures and on ex vivo biofilm samples. Fixation and permeabilization protocols were tested and optimized.Biofilm and media samples were visualized using confocal (Leica SP8 and Zeiss LSM 880) and epifluorescence (Leica DM6000B) microscopes.
Results: The microbial screening of 1311 samples from 16 periodontitis patients showed that Megasphaera HOT 123, Prevotella HOT 526, Prevotella HOT 315, Aggregatibacter HOT 898and Alloprevotella HOT 912were the most prevalent and abundant phylotypes. Imaging of pure and mixed cultures of A. israelii, P. gingivalisand F. nucleatumand the use of positive and negative controls demonstrated the specificity of the probes used. Spent media samples were better visualized than biofilm samples. P. gingivalis and F. nucleatumcould be observed in several samples. Megasphaera HOT 123 could be clearly visualized as small cocci in media samples. Conclusions: The imaging method devised allowed the specific visualization of phylotype Megasphaera HOT 123 as cocci located in clusters within ex vivo biofilm and media samples.
- …
