Complexity Measures from Interaction Structures

We evaluate new complexity measures on the symbolic dynamics of coupled tent maps and cellular automata. These measures quantify complexity in terms of $k$-th order statistical dependencies that cannot be reduced to interactions between $k-1$ units. We demonstrate that these measures are able to identify complex dynamical regimes.Comment: 11 pages, figures improved, minor changes to the tex

Anti-diarrhoeal Activity of Psidium guajava (Gauva) Aqueous Leaf Extract in Experimental Animals

Aqueous leaf extract of Psidium guajava (Guava) was evaluated for anti-diarrhoeal activity against castor oil-induced diarrhoea in albino rats. 50 and 100mg/kg (body weight) doses of the leaf extract showed a  dose-dependent anti-diarrhoeal activity comparable to a standard antidiarrhoeal drug Diphenoxylate given intraperitoneally at 5mg/kg (b.w.) Also, the extract reduced intestinal transit time in charcoal meal test in the same manner. A 100mg/kg dose of the extract also showed an anti-enteropooling effect comparable to a standard anti-enteropooling agent Chlopromazine (20mg/kg, intraperitoneally). Further studies are needed to isolate the effective components of the leaf extract.Keywords: Anti-diarrhoeal Activity, Psidium guajava, Castor oil induced, Diarrhoe

Quantifying structure in networks

We investigate exponential families of random graph distributions as a framework for systematic quantification of structure in networks. In this paper we restrict ourselves to undirected unlabeled graphs. For these graphs, the counts of subgraphs with no more than k links are a sufficient statistics for the exponential families of graphs with interactions between at most k links. In this framework we investigate the dependencies between several observables commonly used to quantify structure in networks, such as the degree distribution, cluster and assortativity coefficients.Comment: 17 pages, 3 figure

Species Abundance and Colour Preferences of Oviposition by Mosquitoes in Man-Made Containers under Field Conditions in Sokoto, Nigeria

A study was conducted to determine the occurrence and colour preferences of oviposition by mosquitoes in man-made containers under field conditions. A total of nine (9) different colour 2 litre plastic containers were used as artificial mosquito oviposition containers. They were filled with equal amounts of water and placed in the biological garden of the Department of Biological Sciences, Usmanu Danfodiyo University Sokoto. The containers were observed for seven (7) days for mosquito larvae. A total of 319 larvae belonging to four genera, Aedes, Anopheles, Culex and Mansonia were co-habiting/colonizing the garden. The highest occurring genus was Culex with 108 (33.9%) larvae, followed by Aedes with 92 (28.8%), Mansonia 79 (24.8%) and Anopheles with 40 (12.5%)larvae. The colour preference of mosquitoes was in this order: red 25.4 % (81), brown 20.4 % (65), black 16.0% (51), blue 13.2% (42), purple 10.3% (33), pink 7.8% (25), green 6.3% (20), yellow 0.6% (2) and white 0% (0). Although many genera oviposited in more than one colourcontainer, the general distribution of larvae revealed that Aedes and Culex preferred red colour, Mansonia preferred brown container while Anopheles preferred black container. This study shows the importance of colour in determining the breeding sites and thus the occurrence of mosquitoes. The implications of such containers as possible breeding foci of mosquitoes of potential public health significance have been highlighted.Key words: Colour preferences, Man-made containers, oviposition, Mosquito larva

Scalar fields in the de Sitter spacetime

We examine long-wavelength correlation functions of massive scalar fields in de Sitter spacetime. For the theory with a quartic self-interaction, the two-point function is calculated up to two loops. Comparing our results with the Hartree-Fock approximation and with the stochastic approach shows that the former resums only the cactus type diagrams, whereas the latter contains the sunset diagram as well and produces the correct result. We compare our results with the preceding results obtained for the massless scalar field

Growth, micro-structuring, spectroscopy, and optical gain in as-deposited Al2O3:ErAl_2O_3:Er waveguides

Deposition and micro-structuring of $Al_2O_3:Er$ layers with low background losses (0.11 dB/cm) and lifetimes up to 7 ms have been optimized for active devices. Net gain of 0.7 dB/cm at 1533 nm has been measured.\ud \u

Recycling Mixed Plastics Waste as Reductant in Ironmaking

One of the major obstacles to the implementation of an appropriate plastics recycling scheme is the inhomogeneity of many plastics waste. Accordingly, most of the existing recycling schemes require a feedstock that is reasonably pure and contains only items made from a single polymer type. However, in reality, waste plastics contain a mixture of plastic types, and are often contaminated with non-plastic items. This demands sorting out, which is expensive and highly labour intensive. In this work, the reduction of reagent grade iron oxide by mixed plastic waste (MPW) has been investigated through experiments conducted in a laboratory scale horizontal tube furnace. Composite pellets of reagent grade iron oxide (97 % Fe2O3) with MPW [consisting of 50 wt % high density polyethylene (HDPE), 30% polypropylene (PP), 10% low density polyethylene (LDPE) and 10% polyethylene terephthalate (PET)] were rapidly heated at 1520°C under high purity argon gas and the off gas was continuously analysed for CO, CO2 and CH4 using an online infrared gas analyser (IR). The extent of reduction after ten minutes was determined for each carbonaceous reductant and the results were compared with the extent of reduction by conventional metallurgical coke under the same experimental conditions. The results show that iron oxide can be effectively reduced to produce metallic iron using MPW as reductant. An improvement in extent of reduction was observed over metallurgical coke and the individual polymers when MPW was used as reductant. This eliminates the need to sort out individual plastics from municipal solid waste for their effective utilisation as reductants in ironmaking.Keywords: Reduction, Metallurgical coke, Mixed plastics waste, Extent of reductio

Evidence for downregulation of the negative regulator SPRED2 in clinical prostate cancer.

BACKGROUND: SPRED1 and 2 are key negative regulators of MAPK signalling in mammalian cells. Here, we investigate the expression and functional role of SPREDs in prostate cancer. METHODS: A transcriptome bank of microdissected grade-specific primary cancers was constructed and interrogated for transcript expression of prostate cancer genes, known negative signalling regulators as well as SPRED1 and 2. The effect of SPRED2 manipulation was tested in in vitro assays. RESULTS: In a panel of 5 benign glands and 15 tumours, we observed concomitant downregulation of the negative regulators SEF and DUSP1 in tumours with increasing Gleason grade. Profiling in the same cohorts revealed downregulation of SPRED2 mRNA in tumours compared with benign glands (P<0.05). By contrast, SPRED1 expression remained unchanged. This observation was further validated in two additional separate cohorts of microdissected tumours (total of n=10 benign and n=58 tumours) with specific downregulation of SPRED2 particularly in higher grade tumours. In functional assays, SPRED2 overexpression reduced ERK phosphorylation and inhibited prostate cancer cell proliferation and migration in response to different growth factors and full-media stimulation (P<0.001). Conversely, SPRED2 suppression by siRNA enhanced the mitogenic response to growth factors and full media (P<0.001). CONCLUSION: These data suggest first evidence that SPRED2 is downregulated in prostate cancer and warrants further investigation as a potential tumour-suppressor gene