ALBERT

Notes: Lucerne (Medicago sativa L.) sown at 2·8-11·2 kg ha−1 in spring was thinned in the autumn by digging plants from alternate 15- or 30-cm lengths of row. Both thinning treatments decreased the subsequent year stand density by 34%. Yields the following year were reduced by 24 and 17% for the 15- and 30-cm treatments respectively, and the next year by 10% for both treatments. Thinning effects were similar at all sowing rates. During the year following thinning, plants did not grow larger in response to the thinning. Thus, development of compensatory growth by lucerne plants following sudden stand thinning is slow.

Notes: The effect of nitrite and storage temperature and toxinogenesis by Clostridium botulinum in vacuum-packed side bacon was investigated. In two series of experiments (A & B) bacon packs were prepared with levels of 0, 50, 100, 150 and 200 ppm nitrite and inoculated with C botulinum at 102 spores/g and 104 spores/g. Packs A were incubated at 20 and 30° C and packs B at 30°C only. Both were held for a maximum of 32 days and analyzed for toxin at intervals of 2, 4, 8, 16 and 32 days. At 20°C none of the controls without nitrite was found to be toxic after 32 days. At 30°C inhibition of toxin formation at the higher nitrite levels was observed at 32 days. Organoleptic evaluation of the bacon packs stored at 30° C showed about one-third of the toxic samples examined were acceptable to the panel.

Notes: The factors determining resolution in aerial photography of wildlife concentrations are considered and two developments that improve resolution with inexpensive equipment are described. Firstly, a rocking camera mount has been constructed that compensates for apparent image motion resulting from forward movement of the aircraft. The mount allows slower shutter speeds to be used so that aerial surveys can be conducted using high resolution colour film under poor light conditions. Secondly, critical prefocusing to the survey flying height is carried out, even for lenses of short focal length. Aerial photography of grey seal breeding colonies is used to illustrate these developments.

Notes: The Energetic Gamma-Ray Experiment Telescope (EGRET) has observed gamma-rays bursts with the highest energy gamma-rays and the longest high energy emission to date. EGRET measures the high energy gamma-rays with its large NaI scintillator (1 to 200 MeV) and its spark chamber (30 MeV to 30 GeV). The spark chamber also measures time and arrival directions of individual photons allowing locations for the energetic bursts to be determined. Since the Compton Gamma Ray Observatory launch in 1991, EGRET has observed five bursts in the spark chamber with several having gamma-ray energies grater than 1 GeV. The recording breaking burst, GRB940217, had gamma-rays up to 18 GeV and lasted over 5000 seconds. The results for the energetic bursts are presented. The high energies observed from these gamma-ray bursts set constraints for the burst distances.

Notes: In the northern parts of the Needwood and Stafford/Eccleshall Basins, England, the Pebble Beds of the Sherwood Sandstone Group contain thick successions of texturally mature, fluvial pebble/cobble conglomerates which are organized into either horizontal or cross-stratified sets. The horizontally lying sets, generally coarser grained and more poorly sorted than the cross-bedded sets, are usually disorganized and either matrix- or clast-supported, although thin lenses of well-sorted, occasionally openwork units, interpreted as falling stage phenomena, are often present. The cross-stratified conglomerates have foresets exhibiting remarkable textural organization, with a coarse, bimodal (sometimes matrix-supported) part grading upwards or being abruptly overlain by a finer, well-sorted (occasionally openwork) part and finally capped by sandstone. These rhythmic textural changes are attributed partly to an avalanche process at high stage and partly to falling stage conditions. The most common types of vertical association are thick successions of horizontally bedded conglomerates (up to 20 m) and sequences of an upwards coarsening nature (2-12 m) in which cross-stratified sets are overlain by flat-lying sets.The environment of deposition of the gravels is interpreted as one in which water depths at high stage were greater than depths in most modern braided stream plains (proglacial or alluvial fan) but shallower than depths associated with the Pleistocene catastrophic floods from which texturally mature, giant gravel bars have been recorded. Recent braided streams with relatively confined channels and considerable bar/channel relief are better analogues. In particular, medial or mid-channel bars with a two-tier structure (subaqueous and partly emergent portions) may explain the upward-coarsening sequences in which horizontally lying conglomerates overlie cross-stratified conglomerates. The thicker sequences of horizontally stratified conglomerates represent proximal, longitudinal bar deposits.Sheets of pebbly sandstone and argillaceous sandstone lying between the conglomerates, and commonly occurring towards the top of the succession, largely represent deposition from sandwaves and dunes. Finer, interbedded, argillaceous sandstones, siltstones and mudstones are interpreted as overbank and waning-flood deposits.Basin-forming tectonism of increasing intensity probably caused the initial coarsening upwards of the lower part of the succession, whilst more stable tectonic conditions and decreasing relief on the margins of the basins and in the areas of provenance in the Midlands and the Hercynides, account for the upwards-fining of the upper part of the succession.

Notes: Methods were determined for the induction of diploid gynogenesis in the sole, Solea solea (L.), in order to investigate the sex-determining mechanism. The experiments utilized gametes obtained by dissection of fish caught at sea. Activation of eggs with UV-irradiated sole sperm was not feasible but development was initiated by exposure to halibut, Hippoglossus hippoglossus (L.), sperm. These embryos displayed the typical characteristics of haploids and few survived beyond hatching. High levels (〉 90%) of diploidy were induced in such eggs by subjecting them to a cold shock (2°C or 4°C) for 1-2 h about 10-15 min after activation at 12°C. The resultant embryos were indistinguishable from those developing from normally fertilized eggs and were considered to be diploid gynogenomes. Fifteen of these were reared to a length of 5-10 cm by which time gonad differentiation had been initiated. Both sexes were represented, indicating that sex in this species is not determined by a simple XX-XY system with female homogamy.

Notes: A pilot scale study was conducted to measure soluble solid losses of early June, mini and medium sweet peas commercially blanched at 95 ± 1°C for 3 min using a 25 lb (11.34 kg) sample size. Early June peas had smaller losses than mini and medium sweet peas. Dry matter losses were the greatest for the smallest sizes in each variety. Moisture content did not change significantly during blanching but increased after canning. Alcohol Insoluble Solids increased for all sizes in each cultivar after blanching. Recovery of small size peas may be maximized by bypassing blanching and gravity separation.