Risk involves consideration both of the consequences of accidents and the frequency with which the accidents occur. Indeed formally risk is equal to the product of frequency and consequences. The important question of the perception of risk by the public and by the professional is first addressed. Two tenets are proposed as being a suitable summary of the public requirement:

1. If it can happen, then it must not matter.

2. If it matters, then it must not happen.

A mathematical interpretation is placed upon these tenets and is shown to be consistent with various professional safety targets. The tenets do not indicate what numerical values for risk would be acceptable to the public but they do show how the consequences of accidents should diminish as the frequency or likelihood of a particular accident increases. It is argued that the best way of determining what level of risk the public accepts is to be guided by statistics for man-caused accidents. These, it transpires, pose risks which are considerably greater than those implied, for example, by the professional targets for nuclear reactors. The risk posed to the public by two energy installations is summarised. The one installation, situated on Canvey Island, exports energy in the form of gas, some of which (methane) is pumped into a national gas grid. The other installation, the Sizewell “B” Pressurised Water Reactor nuclear power station has not yet been constructed, but a comprehensive risk assessment has been undertaken, the results of which are summarised. The two installations are comparable in the sense that each exports a power of the order of a million kilowatts (in the form of gas in the one case and electricity in the other). Both have been the subject of Public Inquiries. The risks posed by the Canvey installations are accepted, since they only constitute a small fraction of the risks which the public run in any case during the course of their everyday lives. The predicted risks for the PWR are smaller still. The form taken by the risks posed by both installations corresponds broadly with the two tenets. That is to say the greater the consequences the lower should be the frequency of a particular accident.

An unusual form of Asplenium adiantum-nigrum from Scottish and European serpentine sites has been grown for several years under uniform conditions of culture alongside A. adiantum-nigrum of nonserpentine origin, and has been found to retain its characteristic features. The morphological distinctiveness of both types, apparent in juvenile as well as adult plants, has been maintained through successive generations.

Transplant experiments were carried out in order to determine whether serpentine and non-serpentine plants differed also in their physiological response to soil factors. The results suggest that serpentine soils are unfavourable to the growth of non-serpentine A. adiantum-nigrum, particularly at germination and during the early development of the sporophyte. Soil analysis data are presented and briefly discussed.

The experimental evidence presented here, combined with the constancy of the diagnostic differences leading to ease of recognition of the serpentine forms at all ages, suggests that evolution leading to the establishment of ecologically adapted divergent strains is actively in progress.

The experiments to be discussed here all involve the irradiation of cells in early interphase and the observation of these cells, or rather their chromosomes, at the first mitosis following radiation exposure. The irradiation of such G1 cells results in the formation of chromosome-type aberrations that are a consequence of breaks or exchanges involving the whole chromosome, both chromatids being affected in exactly the same way and at identical loci. These chromosome-type aberrations are of various kinds and a large proportion of them are very easy to detect cytologically. The four main types that are normally studied by cytologists, since they can be easily and objectively scored, are the terminal and interstitial deletions and the dicentric and ring aberrations (see text-fig. 1).

Estuarine development was contemporaneous with the onset of glaciation. In the Tay estuary fluvial erosion dominated the downcutting, with minor glacial modification; in the Forth estuary glacial scouring dominated the erosion of rockhead.

Extensive subsurface exploration in connection with road improvement and foundations for bridge building and electricity pylon construction have yielded information on the fill of the Tay and Earn valleys. In addition to geophysical investigations the surveys include boreholes along a 20 km long section from Kinfauns to Longforgan, revealing deposition of lodgement tills followed by Arctic Clays, believed to have been deposited partly from floating ice. Above it are coarse sands and gravels, perhaps outwash deposits. Both were deeply dissected during a fall of sea level associated with a channel cut to − 37 m O.D. at Dundee.

Erosion and marine planation during lowered sea levels produced laterally extensive buried gravels.

A rise of sea level led to burial of the eroded surface by early estuarine sediments which become finer upwards and terminate in peats, dated at 8500 b.p. Further erosion was followed by a second phase of estuarine sedimentation. This produced the carse deposuts whose terminal peats accumulated at 5500 b.p.

The modern estuarial deposits partly bury those of the two preceding estuaries, which exert a major control on the migrations and depth of the modern channels.

The main interest in the healing of an injured nerve centres, naturally, on the regeneration of the axon. As the birthplace of the new fibres the central stump has attracted and received considerable attention, and the histology of the peripheral stump has been very fully investigated, particularly by Cajal (1928), and more recently by Young (1942), Weddell and Glees (1941), and Holmes and Young (1942). In contrast to our accurate knowledge of conditions in the central and peripheral stumps, there are scant records of the progress of repair at the injured region when the lesion results in the total destruction of the nerve fibres.

In the course of experiments on rabbit sciatic nerves designed to test the effect of interference with the blood supply on the regeneration of injured nerve (Bacsich and Wyburn, 1945 a and 1945 b) total degeneration was accomplished by a severe crush with artery forceps. This gave us an opportunity to study the early histological changes in the crushed areas of these nerves.

The vegetation of the peatland of Lewis is described. Several different types of mire are distinguished according to their morphological features. The gradual transition from minerotrophic conditions within valley mires to fully ombrotrophic conditions in the blanket mires of watersheds is demonstrated. Whilst most of the blanket mire of Lewis is affected by severe peat erosion, examples were chosen to demonstrate the nature of the flora and vegetation within those mire systems at present unaffected by erosion, as well as the more characteristic eroded peatland.

In the upper Tay Estuary the marshes bordering the northern intertidal mud-flats are dominated by Phragmites communis in the west, with Juncus gerardi becoming more important eastwards, where Aster tripolium is also significant. Sedimentation on the surface of the marshes at Kingoodie and Invergowrie has been measured at monthly intervals over a twenty-three month period, using stake implants to provide local marker levels. The marsh surfaces were at their greatest heights in early summer and fell during autumn and winter. Maximum accretion rates were measured in spring on the outer marshes at both sites, where net accretion over the entire period was greatest. The net accretion in the Phragmites marsh was 2.5 mm, in the Aster belt 5 mm, in established Juncus 9 mm and in newly colonising Juncus 8.7 mm, whereas on the adjacent Kingoodie mud flats there was net stability over the twenty-three-month interval. Accretion was less at Invergowrie (3–5 mm) than at Kingoodie (2.5–9 mm). Monthly analysis of the upper 0.5 cm of the surface sediments showed the Invergowrie marsh sediments to be sandier than those of Kingoodie. Silts and clays deposited on the outer marsh surface in spring migrate landward during the summer and autumn. The apparent annual net accretion varied greatly with the specific month used for comparison, with 13 mm net losses based on November figures and 10 mm gains using January data.

The deep region lying between the Scottish and Irish continental shelves and the Rockall Bank is known by two names, the Rockall Channel and the Rockall Trough. Nansen (1913) refers to the Rockall Channel as the route of the “Gulf Stream” (Krummel's Irish Current) northeastwards through the Faeroe-Shetland Channel. The name “Rockall Trough” was adopted later, principally by the geologists and is in more general use today by all disciplines. The term is given precedence in this Bibliography.

The Shetland Islands lie between latitudes of approximately 60° and 61° North, over 100 miles north of the Scottish mainland. They are influenced by the North Atlantic Drift so that the climatic conditions are much less severe than for other land masses, for example in Southern Greenland where the mean temperature for five months of the year is below freezing. The environment in all its considerable heterogeneity is well described in The Natural Environment of Shetland (Goodier 1974) and in The Natural History of Shetland (Berry & Johnston 1980). Briefly the islands lie on the western oceanic fringe of Europe, have approximately 1450 kilometres of coastline and an area of 1468 square kilometres. The geology is varied and geomorphologically the islands constitute a drowned range of glaciated hills situated on the continental shelf. The coast consists of extensive areas of cliffs and voes with relatively few beaches. In general, the ‘outer’ coasts, especially on the west, are exposed high energy environments. In contrast, the inner coasts, often voes, are deep sheltered inlets. The land itself tends to be hilly and, where it has not been stripped for agricultural use, is blanketed with peat, with the main vegetation heather (Calluna vulgaris) and cotton sedge (Eriophorum angustifolium). Approximately 10% of the land is covered by rushy vegetation and there is very little relict scrub though there are one or two planted woodland plots. The original scrub was largely eradicated by man who arrived in Shetland from Iberia about 3500 BC. Colonisers from Scandinavia arrived in the eighth century and have had a lasting influence on the culture of the islands. In 1971 the human population was about 17327 and in 1989 was 23 214 (SIC 1992).

The relationship between stand structure of Calluna vulgaris and the ability of Betula spp. to establish was examined at Dinnet Moor, Aberdeenshire. As a result of management by burning, a series of even-aged stands of Calluna is available including recently-burnt examples and stands with Calluna in the pioneer, building, mature and degenerate phases. Uneven-aged stands were included for comparison. The density of birch was found to be high very shortly after burning, much less in pioneer phase stands and minimal in the building and mature phases, indicating high mortality as the stand ages. Some indication of slightly higher densities in degenerate stands was obtained, suggesting some recruitment at this stage. Comparisons of the age of individual birches (seedlings or saplings) with that of the adjacent Calluna showed that, in general, birch is established very shortly after Calluna begins to regenerate, the surviving birch individuals being consistently one or two years younger than the Calluna. Again, results indicated little or no recruitment after the Calluna stands enter the building phase. Experimental introduction of birch seedlings to stands of various age since burning showed that survival and performance was best in the pioneer stands, and poorest in building stands.

It is concluded that birch is virtually excluded by dense Calluna stands in the building and mature phases, and that carefully controlled management involving regular burning may therefore prevent the entry of birch. However, occasional fires followed by slow or patchy Calluna regeneration may provide ideal conditions for birch establishment.

In this paper the subject of faunal zonation in the ocean floor from the intertidal, and over the continental shelf, slope and rise and to the abyssal plain is examined on the basis of faunal change at the generic and species level. The region investigated over a period of five years aboard R/V Eastward is a Beaufort-Bermuda transect, approximately 75 kilometres wide and 500 kilometres long and bounded between 32° and 36°N latitude and 64° and 79°W longitude. A new method, involving numerical indices reflecting changes in the composition of taxa, endemism and diversity between adjacent depth levels, was developed for defining faunal boundaries. Isotherms and isobaths utilised by earlier authors for characterising deep-sea boundary on a global scale do not coincide with natural faunal boundaries. This study analyses the vertical distribution of 128 species of isopod crustaceans and 28 species of large epibenthic invertebrates. The zonation patterns seem to correspond with correlations in environmental conditions such as currents, topography and sediments.

We suggest four major vertical faunal provinces, characterised at the generic level, namely (1) the Intertidal Faunal Province; (2) the Shelf Faunal Province; (3) the Archibenthal Zone of Transition; and (4) the Abyssal Faunal Province and internal zones within these characterised at the species level. The main aspects of interest include the presence of a narrow ‘meso abyssal zone’ with a species maximum, the demonstration of the true transitional nature of the Archibenthal Zone in biotic and abiotic factors and the characteristic low-biomass Red Clay environment showing definite faunal isolation from the continental margin.

The meagre history of the study of the fungi of birchwoods in Britain is offered as an introduction to more recent studies in the British Isles and in continental Europe. Four categories of fungi (parasites, suspected mycorrhizals and lignicolous and humicolous saprophytes) are recognized and discussed. Examples of the most frequently found species-associations are given in relation to environmental factors.

A correlation has been firmly established, in a wide range of plants, between environmental stress, the onset of senescence, loss of viability in seeds and the development and accumulation of a stable organic free radical. On the basis of the EPR response obtained at 95 GHz (W-band) and ENDOR spectra, and comparisons with quinone radical anions, we present evidence from contrasted plant species, plant tissues and sub-cellular fractions that this stable radical originates from one or more quinones possibly, though perhaps not exclusively, associated with stressed or age-impaired photosynthetic and respiratory electron transport chains. The radical appears to be ubiquitously associated with sub-lethal stress-induced damage and with senescence and arises during the sub-cellular structural and biochemical processes associated with the final phases of metabolism prior to death. As the free radical persists for some considerable time after death, it may have value in long-term studies of seed viability and in broader areas of plant pathology and stress physiology.

Grain stored in bulk forms a man-made ecosystem with a limited, non-regenerating energy supply. However, frequent interference results in an immature, unstable ecosystem with a relatively simple structure and composed of species with limited specialisation, and high growth and reproductive rates. Microbial colonisation commences soon after ear emergence, by what have been termed “field” fungi. These usually have a minimum water potential for germination of −22.4 MPa (> 0.85 aw), have to contend with large diurnal changes in environmental conditions and seldom develop further in store. Sometimes, especially in humid tropical climates, species more typical of stored grain (“storage fungi”) also develop before harvest, and even produce mycotoxins. This differentiation between fungi characteristic of field or store is historical and their classification on ecological requirements would be preferable.

The distributions of the four variables—temperature, salinity, currents and dissolved oxygen—are discussed with particular reference to the Scottish west coast. In fjords, the distributions are related to the sources of change—tides, freshwater runoff, winds and, in the case of currents, to friction, which makes currents very variable over small areas. Current speed in floating cages has been found less than that outside. A model of the oxygen concentration in such a cage has been used to examine the conditions of current and fish stocking density under which the cage can be operated without reaching dangerously low oxygen concentrations.

Typical phytopathological defence reactions of tobacco have been studied in response to ozone. After a single standard ozone pulse (5 h, 150 nl 1−1) β-l,3-glucanase was induced up to 40-fold in the sensitive tobacco cv. Bel W3, which developed necrotic lesions following the treatment. The activity was elevated 10-fold in the tolerant Bel B without concomitant injury. A decrease within 24 h occurred only in Bel B. Tyramine hydroxycinnamoyl-CoA transferase activity was induced 6- to 7-fold in both cultivars with a maximum after 5–8 h. Tyramine conjugates as the product of this reaction could not be isolated and were apparently rapidly integrated into the cell wall. Precultivation of Bel B plants in a greenhouse containing up to 70% of the outdoor ozone concentration resulted in a 4-fold induction of β-l,3-glucanase and a further increase after an administered ozone pulse. Pretreatment (30 nl 1−1 ozone, 7 h per day, 23 days) of sensitive Bel W3 caused increased injury and ethylene formation upon a subsequent ozone pulse. β-l,3-glucanase was induced to the same level as in non-pretreated control plants. In a comparison with other major air pollutants (SO2, NO2), only ozone induced the above reactions. However, a combined treatment of ozone and NO2 led to synergistic effects. These data indicate that ambient ozone is able to change the phytopathological disposition of plants. This finding may have practical significance for the usual plant experiments carried out in greenhouses with non-filtered air.

Oestrogen regulates the growth of human breast cancer cell lines ZR-75–1, T-47-D and MCF-7 (KO and McGrath). Basal cell growth can be reduced (T-47-D) or eliminated (ZR-75–1) by prior growth in the absence of steroid and phenol red for three weeks, demonstrating that oestrogens can have long-lasting effects on cells in culture (termed “steroid memory”). Effects of oestradiol on different cell biological parameters are described and interaction with other steroids and serum growth factors is discussed. Antioestrogen action in these cell lines is affected by at least five parameters: (1) presence of phenol red, (2) time in culture, (3) cell density, (4) antioestrogen concentration, (5) steroid memory.

An in vitro model for loss of oestrogen sensitivity in breast cancer is presented. Both dependent (ZR-75–1) and responsive (T-47-D) cells lose oestrogen sensitivity when deprived of steroid in the long term but show a gradual increase in growth. For ZR-75–1 cells, the effects appear to be clonal but occur at a high frequency (about 1 in 1,000 cells). Parallel alterations in sensitivity to other steroids, antioestrogens and serum growth factors are shown. Molecular markers of this action are described and the results compared with the well-established model for loss of androgen/glucocorticoid sensitivity in SI 15 cells.

Three main types of Hebridean freshwater lochs occur in the Loch Druidibeg National Nature Reserve; eutrophic calcareous machair lochs near the Atlantic coast, mesotrophic lochs on the edge of the moor and oligotrophic lochs on the peatlands. Chloride/calcium concentrations, highest in lochs near the sea, fall away rapidly inland and are lowest in the moor lochs. The fauna of eutrophic and mesotrophic lochs includes a few euryhaline brackish-water species Potamopyrgus jenkinsi, Diaptomus wierzejskii, Neomysis integer and Gammarus duebeni. G. duebeni alone penetrates the oligotrophic lochs. Freshwater sponges are widespread but are absent from the machair lochs and there are no triclad planarians. The fauna of fast and slow stream segments is described. Loch Bee, a man-made lagoon, unlike the open brackish lochs of North Uist, is an unstable habitat and its fauna has changed considerably since it was investigated in 1933. The fauna consists mainly of brackish-water species and a few stenohaline marine species which are confined to its seaward ends. The sequence of faunistic change in the Howmore estuary, Lochs Roag and Fada, a Site of Special Scientific Interest (SSSI), is described; the brackish-water fauna is reduced by the volume of fresh water passing through the system. A brief account is given of the unusual dominance of Hyalinella punctata and Potamopyrgus jenkinsi in Loch Ardvule (SSSI), South Uist.

When bone marrow (BM) is taken, cells in suspension are accessible to antibodies. BM transplantation is therefore an ideal situation for using monoclonal antibodies in therapy. These applications include prevention of graft versus host disease by eliminating T cells from allogeneic BM marrow, and the elimination of residual malignant cells from autologous bone marrow. Me Ab-s are currently tested for the removal of residual leukaemic cells in the common form of acute lymphoblastic leukaemia (ALL) and in thymic ALL. Encouraging experiments also indicate that the removal of B leukaemias/lymphomas from the BM will also be feasible.

The review summarises the various ways Ab-s can damage coated ‘unwanted’ cells (opsonisation, complement mediated lysis, and Ab-s coupled to toxins), and the principles for selecting Me Ab-s for BM transplantation.