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The rocky shores of the north-east Atlantic have been long studied. Our focus is from Gibraltar to Norway plus the Azores and Iceland. Phylogeographic processes shape biogeographic patterns of biodiversity. Long-term and broadscale studies have shown the responses of biota to past climate fluctuations and more recent anthropogenic climate change. Inter- and intra-specific species interactions along sharp local environmental gradients shape distributions and community structure and hence ecosystem functioning. Shifts in domination by fucoids in shelter to barnacles/mussels in exposure are mediated by grazing by patellid limpets. Further south fucoids become increasingly rare, with species disappearing or restricted to estuarine refuges, caused by greater desiccation and grazing pressure. Mesoscale processes influence bottom-up nutrient forcing and larval supply, hence affecting species abundance and distribution, and can be proximate factors setting range edges (e.g., the English Channel, the Iberian Peninsula). Impacts of invasive non-native species are reviewed. Knowledge gaps such as the work on rockpools and host–parasite dynamics are also outlined.
A time dependent x-ray diagnostic technique based on the fast rise time characteristics of unitary crystals is demonstrated, and a correction for decay time is determined for anthracene crystals. The method has a probable time resolution capability better than 10 picoseconds. The shape of the x-ray pulse emitted by laser-generated plasmas is measured by this method and found to be similar to the shape of the laser pulse for laser pulse widths of 1.5-3.5 nanoseconds.
The radiation from plasmas produced by the interaction of a pulsed laser and a solid target can be made to fall in the soft x-ray regime. The x-rays can serve as an alternative to the increasingly important synchrotron radiation facilities for a variety of techniques such as Extended X-ray Absorption Fine-Structure Spectroscopy and X-ray Lithography. In addition, the x-rays are of special interest for general microradiography of thin samples.
This study aimed to describe the transmission dynamics, the serological and virus excretion patterns of Nipah virus (NiV) in Pteropus vampyrus bats. Bats in captivity were sampled every 7–21 days over a 1-year period. The data revealed five NiV serological patterns categorized as high and low positives, waning, decreasing and increasing, and negative in these individuals. The findings strongly suggest that NiV circulates in wild bat populations and that antibody could be maintained for long periods. The study also found that pup and juvenile bats from seropositive dams tested seropositive, indicating that maternal antibodies against NiV are transmitted passively, and in this study population may last up to 14 months. NiV was isolated from the urine of one bat, and within a few weeks, two other seronegative bats seroconverted. Based on the temporal cluster of seroconversion, we strongly believe that the NiV isolated was recrudesced and then transmitted horizontally between bats during the study period.
We report optical, thermal, and transport studies on Kr+ implanted ladder (BBL) and rigid-rod ( PBO and PBZT) polymers, with an ion energy of 200 keV and dosage of 4 × 1016 / cm2. Both pristine and ion implanted polymers were studied using X-ray photo-electron spectroscopy (XPS), optical spectroscopy (IR and UV-Vis), thermogravimetric analysis (TGA), and temperature dependent DC conductivity (σ(T)). The XPS and IR results show a reduction in the heteroatoms and increase in the relative carbon content. After ion implantation, each polymer had a similar electronic structure, showing broad band metallic behavior. TGA data shows that each implanted polymer retains its thermal stability. σ(T) of the implanted polymers has the weakest temperature dependence of any conducting polymer reported, in accord with a disordered metal.
Light emitting electroluminescent devices have been studied in which the conjugated light emitting polymer is separated on both sides from the device electrodes by a film of nonconducting polyaniline. The devices operate under an AC applied potential.Aluminum, copper or gold serve as the metal electrodes. Flexible, completely organic polymer dispersed liquid crystal light valves have been fabricated from transparent plastic substrates on which a conducting film of polypyrrole has been deposited. A new concept, “microcontact printing”, is being investigated for patterning the polypyrrole.
When thin films of polyaniline (emeraldine base, EB) are deposited on glass substrates from aqueous solutions of polymerizing aniline (“in-situ” EB-I film), they exhibit a Vis/UV spectrum in which the exciton peak has an absorption maximum at ∼600 nm; exposure to NMP vapor results in a shift of this peak to ∼650 nm (EB-II film). Doping of EBI film by aq. HCl gives the characteristic Vis/UV spectrum of “tight coil” doped polyaniline with a localized polaron peak at ∼820 nm. Treatment of EB-II film with HCl in a similar manner gives the characteristic spectrum of “expanded coil” doped polyaniline in which the ∼820 nm peak has disappeared and is replaced by a free carrier tail. It is concluded that EB-I and EB-II exist in “tight coil” and “expanded coil” molecular conformations respectively which do not change on doping in aqueous HCl.
Most conjugated polymer-based light-emitting devices have been shown to be tunnel diodes which can only operate under forward DC driving field. Recently we have reported the fabrication of symmetrically configured AC light-emitting (SCALE) devices based on heterocyclic aromatic conjugated polymers. By adding an “insulating” layer (e.g. emeraldine base (EB) form of polyaniline) on both sides of the emitting layer, the SCALE devices emit light under both forward and reverse DC bias as well as AC driving voltage. The SCALE device structure ITO/J/emitterFl/M, has been shown to be quite general, and can be applied to a variety of electroluminescent polymers (emitter), insulating polymers (I) and electrode materials (M). Here we summarize and compare the performance of SCALE devices fabricated with different emitter, insulator, and electrode materials. The role of the insulating layer in the SCALE device operation is examined and a model that emphasizing the interface states is proposed to account for the device operation.
In February 2007 an outbreak of Nipah virus (NiV) encephalitis in Thakurgaon District of northwest Bangladesh affected seven people, three of whom died. All subsequent cases developed illness 7–14 days after close physical contact with the index case while he was ill. Cases were more likely than controls to have been in the same room (100% vs. 9·5%, OR undefined, P<0·001) and to have touched him (83% vs. 0%, OR undefined, P<0·001). Although the source of infection for the index case was not identified, 50% of Pteropus bats sampled from near the outbreak area 1 month after the outbreak had antibodies to NiV confirming the presence of the virus in the area. The outbreak was spread by person-to-person transmission. Risk of NiV infection in family caregivers highlights the need for infection control practices to limit transmission of potentially infectious body secretions.
Rose rosette disease, lethal to multiflora rose and indigenous to North America, has been proposed as a biocontrol agent for multiflora rose, a noxious weed in the central and eastern United States. Studies in experimental plots showed that the disease can be intensified by grafting infected shoots onto plants in established stands (i.e., augmentation). The rate of disease spread in augmented plots was significantly faster compared to epidemics in nonaugmented plots at 5 locations. Augmentation provided effective control 3 to 5 yr after implementation. Risk to ornamental rose seems to be low under conditions of this study. Plots to assess risk of the disease to ornamental roses, located at distances greater than 100 m from augmentation sites, showed no infection during the 3 yr of this study.
Plasmodium knowlesi merozoites were prepared by the polycarbonate sieving method of Dennis, Mitchell, Butcher & Cohen (1975). Merozoite function was assayed by their attachment to and invasion of rhesus erythrocytes at 37 °C. The early merozoites from the culture chamber were the most invasive, although maximum numbers of merozoites appeared later. Merozoites were most stable when incubated at room temperature (23 °C). At 37 and 0 °C invasiveness rapidly declined to zero. Attachment was rapidly lost at 37 °C but was retained at 0 °C. Attachment was unchanged in the pH range 6·8–7·9 but invasion was reduced at pH 7·9. The presence of l-fucose, d-galactose, d-glucose, d-mannose, N-acetyl-d-galactosamine or N-acetyl-D-glucosamine did not reduce invasion. Attachment and invasion were greatly reduced or abolished by the presence of 2·5 mm EDTA or EGTA, by lactoper-oxidase-catalysed iodination of the merozoites, or by treatment of the merozoites with trypsin at a concentration of 1 μg/ml or greater for 10 min at 23 °C.
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