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

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.

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

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

Low cost transport in Asia : a comparative report on five cities

Describes the settings, physical and operating features, and socio-economic characteristics of low-cost transports and the groups involved in their development and operation. Includes bibliography

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

Infection Process Of Entomopathogenic Fungi Metarhizium Anisopliae In The Tetranychus Kanzawai (Kishida) (Tetranychidae: Acarina)

The importance of fungal attack to acarina has been observed but not yet on Tetranychus kanzawai. When infected mite, either within in a same species or even in a different species of entomopathigenic probably have similar signs and simptoms to mites. Characteristic of entomopathogenic fungus to Tetranychus kanza-wai was investigated. Three selected isolates of Metarhizium anisopliae, from Philippines and Indonesia were evaluated. The following aspects were investigated: (1) Bioassay tes of virulence, (2) Koch Postulate and (3) Infection process on each fungus against mite. Virulence of Metarhizium anisopliae was 1.4 X 103, 7.2 X 102 , 5 X 102 PIB per ml on Ma4, Ma5 and Ma6, respectively. On Koch Postulates, Reinoculation and reisolation of all seven isolates from infected T. kanzawai showed definite signs of infection. This demonstrated its entomopathogenic capacity. In this experiment, adult mites were sprayed with 108 per ml concentrations of conidia observed under light microscope and Scanning Electron Microscopy (SEM). The result found T. kanzawai was very susceptible to three isolates M. anisopliae. In the end of the trials, fungal growth was detectable as early as 2 until 4 days of observation. Infection process with microphoto-graph and Scanning Electro Microscopy showed attachment, germination and penetration, extrusion and conidiogenesis fungal form

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

Reestructuración de la agricultura e inseguridad alimentaria. Las iniciativas y retos de los pequeños productores en Chiapas

Organismos internacionales y especialistas coinciden en que los problemas de crisis e inseguridad alimentaria se asocian con las políticas que diferentes países aplicaron en las últimas dos décadas, las cuales desmantelaron los programas de fomento a la agricultura, en particular de los pequeños productores. Aunque esta reestructuración neoliberal se realizó de manera heterogénea, los retos para reactivar la producción agroalimentaria sustentable y de calidad, así como de elevar los ingresos rurales, son de gran magnitud, y en ocasiones no aparecen en los objetivos de la política nacional. En este documento analizamos la forma en que la reestructuración ha impactado en ciertos patrones de creciente inseguridad alimentaria en México y Chiapas, así como la manera en que pequeños productores han adaptado y retado este proceso, constituyendo iniciativas con las que revalorizan la lógica de la agricultura campesina y de pequeña escala