Transparency in organisms

Summary The occurrence in animal phyla of species having a relatively transparent body is noted and measurements of the transmittance of medusae made in a spectrophotometer are reported, but the approximate nature of the results obtained with a commercial instrument and the importance of the correct physical design of the measuring apparatus are emphasized. The application to invertebrates of the structural explanation of the predominant transmission of incident light by the vertebrate cornea is discussed and the role of other factors considered. Destructive interference of the scattered rays, sufficient to account for the transparency of the cornea, has been shown not to demand a completely regular arrangement of collagen fibres. The small diameter and regularity of the fibrillar components in the muscles ofSagitta may be adequate to account for their transparency.I am grateful to Dr.D. M. Maurice for the encouragement of this interest, to Dr.E. G. Jordan for electron micrographs ofSagitta and to Mr.G. Ross (Department of Physics, Queen Elizabeth College) for helpful and critical discussion.     

Variation in interleukin 7 receptor alpha chain (IL7R) influences risk of multiple sclerosis

Multiple sclerosis is a chronic, often disabling, disease of the central nervous system affecting more than 1 in 1,000 people in most western countries. The inflammatory lesions typical of multiple sclerosis show autoimmune features and depend partly on genetic factors. Of these genetic factors, only the HLA gene complex has been repeatedly confirmed to be associated with multiple sclerosis, despite considerable efforts. Polymorphisms in a number of non-HLA genes have been reported to be associated with multiple sclerosis, but so far confirmation has been difficult. Here, we report compelling evidence that polymorphisms in IL7R, which encodes the interleukin 7 receptor alpha chain (IL7Ralpha), indeed contribute to the non-HLA genetic risk in multiple sclerosis, demonstrating a role for this pathway in the pathophysiology of this disease. In addition, we report altered expression of the genes encoding IL7Ralpha and its ligand, IL7, in the cerebrospinal fluid compartment of individuals with multiple sclerosis.     

Regulation of HERG (KCNH2) potassium channel surface expression by diacylglycerol

The HERG (KCNH2) channel is a voltage-sensitive potassium channel mainly expressed in cardiac tissue, but has also been identified in other tissues like neuronal and smooth muscle tissue, and in various tumours and tumour cell lines. The function of HERG has been extensively studied, but it is still not clear what mechanisms regulate the surface expression of the channel. In the present report, using human embryonic kidney cells stably expressing HERG, we show that diacylglycerol potently inhibits the HERG current. This is mediated by a protein kinase C-evoked endocytosis of the channel protein, and is dependent on the dynein–dynamin complex. The HERG protein was found to be located only in early endosomes and not lysosomes. Thus, diacylglycerol is an important lipid participating in the regulation of HERG surface expression and function.     

Fractal morphology, imaging and mass spectrometry of single aerosol particles in flight

The morphology of micrometre-size particulate matter is of critical importance in fields ranging from toxicology to climate science, yet these properties are surprisingly difficult to measure in the particles' native environment. Electron microscopy requires collection of particles on a substrate; visible light scattering provides insufficient resolution; and X-ray synchrotron studies have been limited to ensembles of particles. Here we demonstrate an in situ method for imaging individual sub-micrometre particles to nanometre resolution in their native environment, using intense, coherent X-ray pulses from the Linac Coherent Light Source free-electron laser. We introduced individual aerosol particles into the pulsed X-ray beam, which is sufficiently intense that diffraction from individual particles can be measured for morphological analysis. At the same time, ion fragments ejected from the beam were analysed using mass spectrometry, to determine the composition of single aerosol particles. Our results show the extent of internal dilation symmetry of individual soot particles subject to non-equilibrium aggregation, and the surprisingly large variability in their fractal dimensions. More broadly, our methods can be extended to resolve both static and dynamic morphology of general ensembles of disordered particles. Such general morphology has implications in topics such as solvent accessibilities in proteins, vibrational energy transfer by the hydrodynamic interaction of amino acids, and large-scale production of nanoscale structures by flame synthesis.     

‘Holding’ and ‘endorsing’ claims in the course of scientific activities

My principal aims are to show that holding, adopting and endorsing (definitions of which I provide) are distinct cognitive attitudes that may be taken towards claims at different moments of scientific activities, and that none of them are reducible to acceptance (as defined by Jonathan Cohen); to explore in detail the differences between holding and accepting, using the controversies about GMOs to provide illustrations; and to draw some implications pertinent to democratic decision-making concerning public policies about science and technology, and to the responsibilities that scientists thereby incur.     

New records and habitat information for Sorex merriami in Nebraska

We report the collection of 8 additional specimens of Sorex merriami from northwestern Nebraska; previously only 2 specimens had been collected in the state. The new specimens were captured in pitfall traps and Sherman live-traps from 1979 through 1996 in Dawes, Sheridan, and Sioux counties. These individuals were caught together with Sorex cinereus and several rodent species in a variety of grassland habitats, including disturbed roadsides dominated by native and introduced grasses and forbs, grassland openings in forests of ponderosa pine, and an open, dry grassland. Seven of the new specimens, captured in late May, early June, and December, were young-of-the-year, and 4 of these were not in reproductive condition; reproductive status of the other 3 was not assessed. One individual, captured in late May, was an old male in reproductive condition.     

The eagle and the starlings: Galileo’s argument for the autonomy of science—how pertinent is it today?

After Galileo’s argument for the autonomy of science is analysed and adapted to take into account later developments of scientific practices, we conclude that, in the final analysis, it is not compelling. Nevertheless, Galileo’s argument still provides a useful point of reference, for aspects of it can be interpreted to anticipate central components of the often acclaimed ideal of science as value free, so that appraising it contributes to the larger purpose of exploring how well that ideal stands up today. Finally, we will argue that residue from Galileo’s struggle with the Church remains with us, making it difficult to identify the conditions that would need to be put into place today for any robust sense of the autonomy of science to be defensible.     

The methodological strategies of agroecological research and the values with which they are linked

The characteristic features of some of the methodological strategies adopted in scientific research in agroecology are discussed. They reflect that agroecology, as an approach to scientific research, is inextricably entangled with the other strands of agroecology (farming practice, social movement, political project); and that adopting agroecological strategies, and upholding the values of environmental sustainability, food sovereignty, social justice and democratic participation, mutually reinforce each other. After outlining the kinds of questions that agroecological research addresses so that it can produce knowledge that informs agroecological farming practices and the long term aspiration of agroecological movements to create an alternative agricultural/food system, and then making summary remarks about methodological strategies in general, three characteristic features of some agroecological strategies are introduced and discussed. The paper concludes with comments on the value of agroecological research.