The ornithologist Alfred Russel Wallace and the controversy surrounding the dinosaurian origin of birds

Over many years of his life, the British naturalist Alfred Russel Wallace (1823–1913) explored the tropical forests of Malaysia, collecting numerous specimens, including hundreds of birds, many of them new to science. Subsequently, Wallace published a series of papers on systematic ornithology, and discovered a new species on top of a volcano on Ternate, where he wrote, in 1858, his famous essay on natural selection. Based on this hands-on experience, and an analysis of an Archaeopteryx fossil, Wallace suggested that birds may have descended from dinosaurian ancestors. Here, we describe the “dinosaur-bird hypothesis” that originated with the work of Thomas H. Huxley (1825–1895). We present the strong evidence linking theropod dinosaurs to birds, and briefly outline the long and ongoing controversy around this concept. Dinosaurs preserving plumage, nesting sites and trace fossils provide overwhelming evidence for the dinosaurian origin of birds. Based on these recent findings of paleontological research, we conclude that extant birds indeed descended, with some modifications, from small, Mesozoic theropod dinosaurs. In the light of Wallace’s view of bird origins, we critically evaluate recent opposing views to this idea, including Ernst Mayr’s (1904–2005) arguments against the “dinosaur-bird hypothesis”, and document that this famous ornithologist was not correct in his assessment of this important aspect of vertebrate evolution.     

Validation of a Remote Sensing Model to Identify Simulium damnosum s.l. Breeding Sites in Sub-Saharan Africa

Background

Recently, most onchocerciasis control programs have begun to focus on elimination. Developing an effective elimination strategy relies upon accurately mapping the extent of endemic foci. In areas of Africa that suffer from a lack of infrastructure and/or political instability, developing such accurate maps has been difficult. Onchocerciasis foci are localized near breeding sites for the black fly vectors of the infection. The goal of this study was to conduct ground validation studies to evaluate the sensitivity and specificity of a remote sensing model developed to predict S. damnosum s.l. breeding sites.

Methodology/Principal Findings

Remote sensing images from Togo were analyzed to identify areas containing signature characteristics of S. damnosum s.l. breeding habitat. All 30 sites with the spectral signature were found to contain S. damnosum larvae, while 0/52 other sites judged as likely to contain larvae were found to contain larvae. The model was then used to predict breeding sites in Northern Uganda. This area is hyper-endemic for onchocerciasis, but political instability had precluded mass distribution of ivermectin until 2009. Ground validation revealed that 23/25 sites with the signature contained S. damnosum larvae, while 8/10 sites examined lacking the signature were larvae free. Sites predicted to have larvae contained significantly more larvae than those that lacked the signature.

Conclusions/Significance

This study suggests that a signature extracted from remote sensing images may be used to predict the location of S. damnosum s.l. breeding sites with a high degree of accuracy. This method should be of assistance in predicting communities at risk for onchocerciasis in areas of Africa where ground-based epidemiological surveys are difficult to implement.     

Mapping the Genetic Variation of Regional Brain Volumes as Explained by All Common SNPs from the ADNI Study

Typically twin studies are used to investigate the aggregate effects of genetic and environmental influences on brain phenotypic measures. Although some phenotypic measures are highly heritable in twin studies, SNPs (single nucleotide polymorphisms) identified by genome-wide association studies (GWAS) account for only a small fraction of the heritability of these measures. We mapped the genetic variation (the proportion of phenotypic variance explained by variation among SNPs) of volumes of pre-defined regions across the whole brain, as explained by 512,905 SNPs genotyped on 747 adult participants from the Alzheimer''s Disease Neuroimaging Initiative (ADNI). We found that 85% of the variance of intracranial volume (ICV) (p = 0.04) was explained by considering all SNPs simultaneously, and after adjusting for ICV, total grey matter (GM) and white matter (WM) volumes had genetic variation estimates near zero (p = 0.5). We found varying estimates of genetic variation across 93 non-overlapping regions, with asymmetry in estimates between the left and right cerebral hemispheres. Several regions reported in previous studies to be related to Alzheimer''s disease progression were estimated to have a large proportion of volumetric variance explained by the SNPs.     

Optimization of parameters for improvement of phenol degradation by Rhodococcus UKMP-5M using response surface methodology

Phenol is a toxic compound and is one of the major pollutants contained in the waste water from petroleum and its downstream industries. Response surface methodology (RSM) was used to optimize medium composition and culture condition for enhancement of growth of Rhodococcus UKMP-5M and phenol degradation rate in shake flask cultures. Phenol and (NH₄)₂SO₄ concentrations as well as temperature were the most significant factors that influenced growth and phenol degradation. Central composite design (CCD) was used for optimization of these parameters with growth, and degradation rates were used as the responses. Cultivation with 0.5 g/L phenol and 0.3 g/L (NH₄)₂SO₄ and incubation at 36 °C greatly enhanced growth of Rhodococcus UKMP-5M, where the final cell concentration increased from 0.117 g/L to 0.376 g/L. On the other hand, the degradation rate was greatly increased in cultivation with 0.7 g/L phenol and 0.4 g/L (NH₄)₂SO₄ and incubation at 37 °C. In this cultivation, the time taken to degrade 1 g/L phenol in the culture was reduced from 48 h to 27 h. The model for both responses was found significant and the predicted values were found to be in a good agreement with experimental values and subsequently validated. Increases in phenol degradation rate during Rhodococcus UKMP-5M cultivation corresponded well with increasing phenol hydroxylase activity.     

Plasma Reflectarrays

This paper investigates the design of four different configurations of plasma reflectarrays. The results provide insight into different radiation characteristics of plasma reflectarrays. The proposed unit cell consists of a cubic glass box filled with argon gas energized with applied AC voltage. The reflectarray reflection coefficient phase variation is achieved by varying the plasma frequency of the energized gas. Four plasma reflectarrays for satellite applications at 12 GHz are proposed (centre feed centre beam, centre feed offset beam, offset feed centre beam, and finally, offset feed offset beam). The finite integration technique is used to analyse the plasma reflectarray.     

Intake of Farmed Atlantic Salmon Fed Soybean Oil Increases Insulin Resistance and Hepatic Lipid Accumulation in Mice

Background

To ensure sustainable aquaculture, fish derived raw materials are replaced by vegetable ingredients. Fatty acid composition and contaminant status of farmed Atlantic salmon (Salmo salar L.) are affected by the use of plant ingredients and a spillover effect on consumers is thus expected. Here we aimed to compare the effects of intake of Atlantic salmon fed fish oil (FO) with intake of Atlantic salmon fed a high proportion of vegetable oils (VOs) on development of insulin resistance and obesity in mice.

Methodology/principal findings

Atlantic salmon were fed diets where FO was partly (80%) replaced with three different VOs; rapeseed oil (RO), olive oil (OO) or soy bean oil (SO). Fillets from Atlantic salmon were subsequently used to prepare Western diets (WD) for a mouse feeding trial. Partial replacement of FO with VOs reduced the levels of polychlorinated biphenyls (PCB) and dichloro-diphenyl-tricloroethanes (DDT) with more than 50% in salmon fillets, in WDs containing the fillets, and in white adipose tissue from mice consuming the WDs. Replacement with VOs, SO in particular, lowered the n−3 polyunsaturated fatty acid (PUFA) content and increased n−6 PUFA levels in the salmon fillets, in the prepared WDs, and in red blood cells collected from mice consuming the WDs. Replacing FO with VO did not influence obesity development in the mice, but replacement of FO with RO improved glucose tolerance. Compared with WD-FO fed mice, feeding mice WD-SO containing lower PCB and DDT levels but high levels of linoleic acid (LA), exaggerated insulin resistance and increased accumulation of fat in the liver.

Conclusion/Significance

Replacement of FO with VOs in aqua feed for farmed salmon had markedly different spillover effects on metabolism in mice. Our results suggest that the content of LA in VOs may be a matter of concern that warrants further investigation.     

Biochemical study on modifying role of variants of leptin gene and its receptor on serum leptin levels in breast cancer

Molecular Biology Reports - The leptin is discharged from breast adipose tissue and is overexpressed in breast cancer (BC). Conflicting relation of leptin with BC was reported. We investigated this...