视觉剥夺猫外膝体神经元最优方位的分布特性

记录和测定了视觉剥夺猫（ｄａｒｋ－ｒｅａｒｅｄｃａｔｓ）外膝体３４４个细胞的方位调谐等感受野特性,多数细胞（８２％）具有方位敏感性（Ｂｉａｓ＞０．１）。最优方位的分布与正常猫类似,偏向于水平方位,但分布特性强于正常猫。与正常猫类似,视觉剥夺猫外膝体细胞的最优方位与该细胞感受野在视网膜上的位置有关,偏向平行于视网膜中心区与感受野中心的连线（向心线）;外膝体内位置相邻近的细胞具有相近的最优方位,亦呈现初步有序排列。结果表明：外膝体细胞最优方位的分布特性与后天视觉经验无关而可能来源于遗传因素。     

Shear sensitivity of insect cells

Conclusions While insect cells can be easily damaged in bioreactors as a result of hydrodynamic forces, it is also relatively easy to prevent this damage. Of several possible damage mechanisms, the best understood and preventable is the attachment of cells to gas-liquid interfaces and the subjection of these attached cells to the hydro-dynamic forces and/or physical forces associated with these interfaces. For example, cells attached to gas bubbles in a bioreactor can be transported into the foam layer where they are physically removed from the cell suspension, or they can be killed when the gas bubble they are attached to ruptures at the medium-air interface at the top of the bioreactor. The easiest method to prevent this damage is through the use of specific surface active compounds, such as Pluronic F-68 or Methocel E-50 which prevent the cells from attaching to the gas-medium interface.     

Estimating the sensitivity of cervical cytology: errors of interpretation and test limitations

The objective of this study was to estimate: (i) the sensitivity of cytologists in recognizing abnormal smears; (ii) the sensitivity of cervical cytology as a method of detecting abnormal smears among those obtained in the presence of cervical intraepithelial neoplasia (CIN). Study subjects were 61 women with a histologically confirmed CIN identified through colpohistological and cytologic screening. For objective (i) new smears were taken from study subjects just before treatment, mixed with routine preparations, interpreted by unaware cytologists and then blindly reviewed by a group of three expert supervisors, who reached a consensus diagnosis. Cytologists classified as positive for squamous intraepithelial lesion (SIL) 30 of the 34 smears judged as positive by supervisors (100% of smears classified as high-grade and 67% of smears classified as low-grade SIL by the supervisors). Our approach, based on creating a set of smears with a high a priori probability of being positive, proved to be an efficient way of estimating errors of interpretation. For objective (ii), smears taken at the moment of diagnosis, just before biopsy, were also reviewed by the same supervisors. These CIN cases were identified among asymptomatic women independently of cytological findings and results are therefore not subject to verification bias. Among the 33 histological CINII/III, four (12%) smears had no atypical cells (three negatives and one unsatisfactory) at review. The same proportion was 26% (four negatives and one unsatisfactory) among the 19 histological CINI. No significant differences in smear content were found between the seven ‘false negatives’ and a sample of ‘true positives’ and ‘true negatives’ for a number of formal adequacy criteria (including presence of endocervical cells). Strong differences were found between positive smears taken just before biopsy and those taken just before treatment (in 11 women the first smear only was positive, while the opposite was never observed), suggesting an effect of punch biopsy in removing lesions.     

Application of life cycle assessment to landfilling

A case study of a life-cycle assessment (LCA) is performed concerning the treatment of household solid wastes in a landfill. The stages considered in this LCA study are: goal and scope definition, inventory analysis and impact assessment. The data of the inventory include the consumption of raw materials and energy through the transport of wastes and the management of landfill, and the corresponding emissions to the environment. Abiotic resource depletion, global warming, acidification, eutrophication and human toxicological impacts have been considered as impact categories for the impact assessment phase of the LCA. A comparison of the environmental impact of the landfilling with and without energy recovery is carried out. Members of the Spanish Association for LCA Development (APRODACV)     

Logné, a peat bog of European ecological interest in the Massif Armorican, Western France: Bog development, vegetation and land-use history

Logné, one of three raised bogs (Hochmoor) in the Massif Armorican, was officially designated as a nature reserve in 1987 and is of considerable ecological interest from botanical, ornithological and herpetological aspects. Palynological investigations reveal the history of local and regional vegetation during the last ca. 4000 years. From the end of the Neolithic Age to the present day, changes in the bog appear to have been considerably influenced by variations in local watertable level that may be of natural origin or caused by human activity. Alder carr withOsmunda regalis, which was the dominant vegetation around the periphery of the bog at ca. 4200 B.P., underwent many changes. Its final demise occurred in Gallo-Roman times when the local landscape took on a distinctly open appearance. The first clear evidence for cereal cultivation relates to the Bronze Age. After a decline in farming at the beginning of the Iron Age, there was a strong renewal of farming in the La Tène period, which included a distinct arable component and also records forJuglans andCastanea pollen. The timing of the introduction of walnut and chestnut to the Massif Armorican is discussed.     

Fire extinguishers: A case study of CFC replacements

In some well-known TEWI (total equivalent warming impact) analyses of CFC alternatives, global warmer emissions in production have not been considered. The authors show that TEWI can be affected significantly by these production emissions, which suggests they should be considered in some TEWI analyses. The paper describes a TEWI analysis for one production sequence, that which leads from chloroform to tetrafluoroethylene and thence to HFC-227ea, a fire extinguishing agent. Numerous other commercial products stem from this sequence as well, including refrigerants, polymers and surfactants—these are summarised in the paper. Particular emphasis is placed on describing the production sequence and its global warming parameters to show that these can indeed be estimated from published information. The TEWI profile is presented at the close.     

Electrophysiology of the visual system in the cricket Gryllus firmus (Orthoptera: Gryllidae): Spectral sensitivity of the compound eyes

The electroretinographic spectral sensitivity of the cricket compound eyes shows the presence of two receptor types, a dominant one at 520 nm and another in the near-u.v. (λ_max 355 ± 5 nm) under dark- and intense chromatic adaptation conditions (Fig. 3). The waveform of the electrical responses elicited by short-wavelength stimuli differ from those elicited by long wavelength stimuli (Fig. 1).     

Sensitivity and response of northern hemisphere altitudinal and polar treelines to environmental change at landscape and local scales

The sensitivity and response of northern hemisphere altitudinal and polar treelines to environmental change are increasingly discussed in terms of climate change, often forgetting that climate is only one aspect of environmental variation. As treeline heterogeneity increases from global to regional and smaller scales, assessment of treeline sensitivity at the landscape and local scales requires a more complex approach than at the global scale. The time scale (short‐, medium‐, long‐term) also plays an important role when considering treeline sensitivity. The sensitivity of the treeline to a changing environment varies among different types of treeline. Treelines controlled mainly by orographic influences are not very susceptible to the effects of warming climates. Greatest sensitivity can be expected in anthropogenic treelines after the cessation of human activity. However, tree invasion into former forested areas above the anthropogenic forest limit is controlled by site conditions, and in particular, by microclimates and soils. Apart from changes in tree physiognomy, the spontaneous advance of young growth of forest‐forming tree species into present treeless areas within the treeline ecotone and beyond the tree limit is considered to be the best indicator of treeline sensitivity to environmental change. The sensitivity of climatic treelines to climate warming varies both in the local and regional topographical conditions. Furthermore, treeline history and its after‐effects also play an important role. The sensitivity of treelines to changes in given factors (e.g. winter snow pack, soil moisture, temperature, evaporation, etc.) may vary among areas with differing climatic characteristics. In general, forest will not advance in a closed front but will follow sites that became more favourable to tree establishment under the changed climatic conditions.