Determining Sustainable Levels of Cumulative Effects for Boreal Caribou

Abstract: Direct and indirect effects of industrial development have contributed, in part, to the threatened status of boreal ecotype caribou (Rangifer tarandus caribou) in Alberta and Canada. Our goal was to develop a model that would allow managers to identify landscape-scale targets for industrial development, while ensuring functional habitat for sustainable caribou populations. We examined the relationship between functional habitat loss resulting from cumulative effects of natural and anthropogenic disturbance, and the rate of population change (Λ) for 6 populations of boreal caribou in Alberta, Canada. We defined functional habitat loss according to 2 variables for which we had a priori reasons to suspect causative associations with Λ: 1) percentage area of caribou range within 250 m of anthropogenic footprint, and 2) percentage of caribou range disturbed by wildfire within the last 50 years. Multiple regression coefficients for both independent variables indicated significant effects on Λ. The 2-predictor model explained 96% (R²) of observed variation in Λ among population units (F_2,3 = 35.2, P = 0.008). The model may be used to evaluate plans for industrial development in relation to predicted wildfire rates and goals for caribou population growth rates.     

Water Stress and Leaf Growth of Field Beans (Vicia faba L.) in the Field: Water Potentials and Laminar Expansion

Field beans were grown in three different irrigation treatments.The growth of each leaf was followed and estimates made of plantwater potential at dawn and of plant water potential, solutepotential, and pressure potential in the afternoon. The growthin area of the leaves against time was fitted with a logisticcurve from which the parameters of leaf growth were defined.The parameters were the area at which a leaf unfolds, the meangrowth rate, and the duration of growth, which combine to givethe final leaf size. Water stress reduced the final leaf sizeby reducing both the area at unfolding and the mean growth rate.The duration of growth was not consistently altered. Final leafsize was closely correlated with the plant water potential inthe afternoon and apparently more with pressure than solutepotential. Vicia faba, field bean, water stress, leaf area, leaf growth, water potential     

United Kingdom national audit of breast fine needle aspiration cytology in 1990–91-organization and level of activity

A survey amongst members of the British Society for Clinical Cytology (BSCC) was performed in 1990 and 1991 into their experience of fine needle aspiration (FNA) cytology of the breast. Here we present the findings of that part of the survey covering organizational aspects of the service and methods of specimen handling. the replies demonstrate differences in approach to many of the topics covered. There is a preference for the examination of direct smears (rather than cytospins) with air dried Giemsa staining and wet fixation Papanicolaou staining finding nearly equal favour. Some perceived problems were highlighted, including availability and funding of training and quality assurance as well as facilities for liaison between pathologists, clinicians and radiologists.     

Consequences for a host–parasitoid interaction of host-plant aggregation, isolation, and phenology

Abstract.  1. Spatial habitat structure can influence the likelihood of patch colonisation by dispersing individuals, and this likelihood may differ according to trophic position, potentially leading to a refuge from parasitism for hosts.
2. Whether habitat patch size, isolation, and host-plant heterogeneity differentially affected host and parasitoid abundance, and parasitism rates was tested using a tri-trophic thistle–herbivore–parasitoid system.
3.  Cirsium palustre thistles ( n = 240) were transplanted in 24 blocks replicated in two sites, creating a range of habitat patch sizes at increasing distance from a pre-existing source population. Plant architecture and phenological stage were measured for each plant and the numbers of the herbivore Tephritis conura and parasitoid Pteromalus elevatus recorded.
4. Mean herbivore numbers per plant increased with host-plant density per patch, but parasitoid numbers and parasitism rates were unaffected. Patch distance from the source population did not influence insect abundance or parasitism rates. Parasitoid abundance was positively correlated with host insect number, and parasitism rates were negatively density dependent. Host-plant phenological stage was positively correlated with herbivore and parasitoid abundance, and parasitism rates at both patch and host-plant scales.
5. The differential response between herbivore and parasitoid to host-plant density did not lead to a spatial refuge but may have contributed to the observed parasitism rates being negatively density dependent. Heterogeneity in patch quality, mediated by variation in host-plant phenology, was more important than spatial habitat structure for both the herbivore and parasitoid populations, and for parasitism rates.     

Some Effects of Temperature and Substrate Content upon Respiration and the Carbon Balance of Field Beans (Vicia faba L.)

The effects of substrate content and temperature upon the productionof carbon dioxide in the dark were investigated in Vicia fabaand Sorghum vulgare, using the time courses for carbon dioxiderelease. No endogenous rhythms were found. With V. faba at highsubstrate contents, a steady rate of respiration was measuredat low temperatures, suggesting that the rate of respirationis limited by a third factor such as enzyme activity. This steadyrate eventually decreased rapidly. There was a first order rateof decrease with time at higher temperatures. Low substratecontents gave a complex decay. The rate of decrease of the rateof respiration was affected by the initial state of the plantsover the same range of rates. Reasons for this are discussed.The temperature sensitivity of respiration was investigated.The respiration of plants with high substrate contents had alower temperature sensitivity than those with low substratecontents. This was further investigated by measuring the stoichiometryof carbon dioxide production in the dark from total solublecarbohydrate (as hexose equivalent). It is likely that incompletehexose respiration, which occurs at high substrate contents,is less temperature sensitive than complete hexose respirationor the respiration of some other substrate. Vicia faba, Sorghum oulgare, carbon dioxide, respiration, temperature, substrate content     

Changes with Age in the Status of Water and Tissue Characteristics in Individual Leaves of Vicia faba L.

Leaf-water potential () and relative water content (R) of leavesat different position on the plant were different on any oneday. This was because the effect of environment on and R andof age on physical and chemical properties of tissues variedwith the position of the leaf. Changes with age in the physicaland chemical properties of a leaf depended on the time it emergedin the life of the plant.     

The assessment of multiple variables on breast carcinoma fine needle aspiration (FNA) cytology specimens: method, preliminary results and prognostic associations

The assessment of multiple variables on breast carcinoma fine needle aspiration (FNA) cytology specimens: method, preliminary results and prognostic associations
We have assessed multiple biological variables on breast carcinoma FNA specimens using a Cytoblock technique. The growth fraction (MIBI), oestrogen receptor (ER), progesterone receptor (PR), p53 mutant protein, c-erbB-2, epidermal growth factor receptor (EGFR), NCRCl Vepithelial membrane antigen (EMA) and DNA plopidy were examined. Objective quantification using image analysis (CAS 200) was applied as appropriate. Fifty cases were examined in this preliminary study. Excellent correlation between the Cytoblock preparations and parallel tissue sections was seen. Of the cancers, 81% were aneuploid with only 19% diploid in character, but 67% of the carcinomas were of histological grade 3. The mean nuclear area staining with MIBl was 31.3% and with ER was 26.7%. Twenty-four percent (24.1%) of the nuclear area showed immunoreactivity with PR. Significant immunostaining was seen in 38%, 46%, 38% and 95% of carcinomas with c-erbB-2, p53, EGFR and EMA, respectively. A significant association between histological grade of the resected tumours and both MIBl (P=0.04) and EGFR (P=0.02) expression in the Cytoblock samples was seen. p53 (P = 0.03) and EGFR (P=0.01) immunoreactivity showed an association with tumour size. EGFR (P=0.04) immunostaining also showed a relationship with the lymph node status of the patient. The technique is, we believe, a useful one for the assessment of multiple variables on breast cytology specimens; these preliminary data suggest that some of these may be useful in predicting prognosis in breast cancer patients.     

Examination of a Model and Data Describing the Effect of Temperature on the Respiration Rate of Crop Plants

Some of the published evidence used in the synthesis and maintenancemodel of plant respiration is discussed in relation to the effectof temperature. Recalculations from the data of de Vries (1975b) give different results from those claimed by him. The modelis considered in terms of the use of substrate in the dark andits production in the light. It is suggested that starvationestimates of maintenance are not valid. The most reliable methodof observing synthesis respiration in whole plants appears tobe by following a discrete pool of substrate, as is possiblewith labelled carbon. Triticum aestivum L., Zea mays L., Helianthus annuus L., Vicia faba L., carbon dioxide, respiration, temperature, substrate content