Hyper-Raman scattering analysis of the vibrations in vitreous boron oxide

Hyper-Raman scattering has been measured on vitreous boron oxide, $v-$B$_2$O$_3$. This spectroscopy, complemented with Raman scattering and infrared absorption, reveals the full set of vibrations that can be observed with light. A mode analysis is performed based on the local D$_{3h}$ symmetry of BO$_3$ triangles and B$_3$O$_3$ boroxol rings. The results show that in $v-$B$_2$O$_3$ the main spectral components can be succesfully assigned using this relatively simple model. In particular, it can be shown that the hyper-Raman boson peak arises from external modes that correspond mainly to librational motions of rigid boroxol rings.Comment: 13 pages, 11 figures, 2 table

Aesthetic Worlds: Rimbaud, Williams and Baroque Form

The sense of form that provides the modern poet with a unique experience of the literary object has been crucial to various attempts to compare poetry to other cultural activities. In maintaining similar conceptions of the relationship between poetry and painting, Arthur Rimbaud and W. C. Williams establish a common basis for interpreting their creative work. And yet their poetry is more crucially concerned with the sudden emergence of visible "worlds" containing verbal objects that integrate a new kind of literary text. This paper discusses the emergence of "aesthetic worlds" in the work of both poets and then examines how a common concern with Baroque form unites them in the phenomenological task of overcoming Cartesian dualism

A homeostatic function of CXCR2 signalling in articular cartilage

Funding This work was funded by Arthritis Research UK (grants 17859, 17971, 19654), INNOCHEM EU FP6 (grant LSHB-CT-2005-51867), MRC (MR/K013076/1) and the William Harvey Research FoundationPeer reviewedPublisher PD

Les conséquences d'un supplément alimentaire sur la dynamique des populations de rongeurs au Sénégal. I - Le cas de Mastomys erythroleucus en zone sahelo-soudanienne

The Mastomys erythroleucus population of a sahelo-sudanian woodland bas been studied from August 1976 to October 1979 on two quadrats : a control quadrat (QC) 2.5 ha in size, and a provisioned quadrat (QA) 4 ha in size, where food pellets were regularly provided twice a week since September 1976 (yearly food supplement : 120 kg/ha/yr). The following changes were observed on the provisioned quadrat : (1) an increased population density, (2) an increased production of young, and (3) an improvement of their survival rate. Two further changes were also noticed : (4) while the number of immigrants was not significantly different on the two quadrats during the experiment, the duration of their stay was greater on the provisioned area than on the control area, and (5) the size of the resident females home ranges was decreased. Whereas the experimental increase in food availability and predictibility triggered in this case an increase in Mastomys erythroleucus population density through a better recruitment, it was not influential in preventing the population decline which took place at a similar rate on both quadrats in 197

The cellular coding of temperature in the mammalian cortex

Temperature is a fundamental sensory modality separate from touch, with dedicated receptor channels and primary afferent neurons for cool and warm. Unlike for other modalities, however, the cortical encoding of temperature remains unknown, with very few cortical neurons reported that respond to non-painful temperature, and the presence of a 'thermal cortex' is debated. Here, using widefield and two-photon calcium imaging in the mouse forepaw system, we identify cortical neurons that respond to cooling and/or warming with distinct spatial and temporal response properties. We observed a representation of cool, but not warm, in the primary somatosensory cortex, but cool and warm in the posterior insular cortex (pIC). The representation of thermal information in pIC is robust and somatotopically arranged, and reversible manipulations show a profound impact on thermal perception. Despite being positioned along the same one-dimensional sensory axis, the encoding of cool and that of warm are distinct, both in highly and broadly tuned neurons. Together, our results show that pIC contains the primary cortical representation of skin temperature and may help explain how the thermal system generates sensations of cool and warm

Les conséquences d'un supplément alimentaire sur la dynamique des populations de rongeurs au Sénégal. II - Le cas de Taterillus pygargus en zone sahélienne

A food supplement was provided every second day during the nine months of the dry season to a population of the gerbil Taterillus pygargus on the former IBP study site of Fété-Olé, Northern Senegal. The effects of this supplementary food were assessed by comparison with the population of a control quadrat set up in the same dry bush savanna. During the first three months of food provisioning, a spectacular increase of Taterillus pygargus numbers was noticed on the provisioned quadrat (QA), as compared to the control area (QT). This was entirely due to a concentration of mature individuals, mostly adult males. Food provisioning also had a beneficiai effect upon the growth curve of young individuals, and on the adult body weight, in both sexes. The breeding season of the females was also lengthened on the provisioned quadrat, but the production of young was not significantly different on the two quadrats. However, food provisioning du ring the lean part of the year was unable to prevent or slow down the sharp population decline of this species which took place from January to June 1977, at Fété-Olé as well as all over Northern Senegal. Such a population crash cannot therefore be ascribed to a mere shortage of foo