Light as a key driver of freshwater biofouling surface roughness in an experimental hydrocanal pipe rig

Biofouling in canals and pipelines used for hydroelectric power generation decreases the flow capacity of conduits. A pipeline rig was designed consisting of test sections of varying substrata (PVC, painted steel) and light levels (transparent, frosted, opaque). Stalk-forming diatoms were abundant in both the frosted and transparent PVC pipes but negligible in the painted steel and opaque PVC pipes. Fungi were slightly more abundant in the painted steel pipe but equally present in all the other pipes while bacterial diversity was similar in all pipes. Photosynthetically functional biofouling (mainly diatoms) was able to develop in near darkness. Different biological fouling compositions generated differing friction factors. The highest friction factor was observed in the transparent pipe (densest diatom fouling), the lowest peak friction for the opaque PVC pipe (lowest fouling biomass), and with the painted steel pipe (high fouling biomass, but composed of fungal and bacterial crusts) being intermediate between the opaque and frosted PVC pipes.     

Hydrologic and geologic factors that influenced spatial variations in loess deposition in China during the last interglacial-glacial cycle: results from proxy climate and GCM analyses

Results from climate proxy and General Circulation Model (GCM) analyses suggest that variations in soil moisture and desert expansion are key hydrologic and geologic factors, respectively, influencing temporal and spatial variations in loess texture and distribution in the Loess Plateau of China. During the last glacial period a reduction in soil moisture led to dune destabilization and a southward expansion of the desert (the source of loess) toward the Loess Plateau. Changes in soil moisture in East Asia may have been influenced by the size and extent of the Fennoscandian ice sheet, and the atmospheric circulation pattern that it induced downstream. These results suggest that both regional factors (i.e. changes in soil moisture and the position of the desert margin) and hemispherical factors (i.e. changes in the size and extent of the Eurasian ice sheets) have influenced loess deposition on the Loess Plateau of China.     

Electrostatic components of drug-receptor recognition. II. The DNA-binding antibiotic actinomycin

The semiempirical molecular orbital method PCILO has been used to study the electronic charge distribution and conformation of the antibiotic actinomycin. Molecular electrostatic potential fields have been constructed in three-dimensional space round the molecule and displayed stereoscopically together with contour maps in the orthogonal planes relative to that of the chromophore. It was found that the drug has a considerable dipole moment and that the electrostatic fields can be separated into two large regions; an area of positive potential surrounds the chromophore and one of negative potential is directed away from the peptide rings. In this and the preceding paper these observations are discussed with respect to drug-receptor recognition phenomena. Pattern-matching of complementary electrostatic fields between the drug and polynucleotide receptor can be discerned.     

Zur m?glichen Funktion und Konvergenz wippender K?rperbewegungen bei V?geln

Summary Many species of wagging birds — e.g. tail-wagging Common and Spotted Sandpiper (Actitis hypoleucos, A. macularia), some Wagtails (Motacillidae), Forktails (Enicuridae) or body-bobbing Dippers (Cinclidae) — inhabit fast-running streams and it appears that the behaviour is a convergent adaption to this habitat. Possible functions are discussed; the hypothesis is given that birds of fast-running streams benefit due to wagging as an optical intraspecific signal (e. g. in territorial or sexual behaviour). Owing to the unfavourable acoustical situation (noise of the running water) and the linear habitat, vocal signals are presumed to be generally less effective than optical signals. Predictions concerning the European species based on this hypothesis are in agreement with the available evidence in literature.     

Mucosal Immunogenicity of Genetically Modified Lactobacillus acidophilus Expressing an HIV-1 Epitope within the Surface Layer Protein

Surface layer proteins of probiotic lactobacilli are theoretically efficient epitope-displaying scaffolds for oral vaccine delivery due to their high expression levels and surface localization. In this study, we constructed genetically modified Lactobacillus acidophilus strains expressing the membrane proximal external region (MPER) from human immunodeficiency virus type 1 (HIV-1) within the context of the major S-layer protein, SlpA. Intragastric immunization of mice with the recombinants induced MPER-specific and S-layer protein-specific antibodies in serum and mucosal secretions. Moreover, analysis of systemic SlpA-specific cytokines revealed that the responses appeared to be Th1 and Th17 dominant. These findings demonstrated the potential use of the Lactobacillus S-layer protein for development of oral vaccines targeting specific peptides.     

The four dimensions of cereal aphids

For most of this century, aphids have been known to infest cereals, but their potential importance does not seem to have been fully appreciated until the early 1950s when they were found to be vectors of barley yellow dwarf virus (Bruehl, 1961). Although this discovery initiated a great deal of research in many countries, especially in North America, very little was done, or thought necessary to be done, in Britain. In 1968, however, some of this complacency was lost when the large numbers of aphids found on the cereals in this country indicated how little was known about them and their effects. Aphids are part of a complex four-dimensional continuum of time and space, and this paper briefly describes some of the results obtained since 1969.     

The Economics Behind an Ecological Crisis: Livelihood Effects of Oil Palm Expansion in Sumatra,Indonesia

While the negative ecological effects of the rapid expansion of oil palm in Southeast Asia are far-reaching and relatively widely studied, the socioeconomic consequences have received much less attention in the literature. We examine whether local farmers in Indonesia benefit from cultivating oil palm. We also look at the impact dynamics and possible spillover effects on other farmers. Our analysis builds on panel data collected from 680 farm households in Jambi Province, Sumatra. We show that oil palm cultivation has significant positive effects on farmers’ livelihoods. The economic gains allow farm households to increase their consumption. Oil palm has lower labor requirements than alternative crops. Hence, oil palm farmers can cultivate larger areas and also reallocate saved labor time to non-farm economic activities, which contributes to additional secondary gains. Policies aimed at regulating further oil palm area expansion will have to account for the economic benefits of this crop for the local population.