The effect of artificial feed on blood biochemistry profile and liver histology of wild saddled bream, Oblada melanura (Sparidae)

Floating fish farms attract a great number of wild fish species, changing their behaviour and physiology. The saddled bream, Oblada melanura, sampled from populations aggregated around the Adriatic fish farm and from natural/control populations, were analysed for differences in eleven blood biochemistry parameters and liver histomorphology. The levels of lactate dehydrogenase (LDH), alkaline phosphatase (ALKP) and urea (URE) in cage-associated saddled bream (428.00±SD 321.56 U/L, 86.13±SD 39.87 U/L and 0.05±SD 0.16 mmol/L, respectively) were significantly lower than those observed in the control specimens (1047.06±SD 505.56 U/L, 125.75±SD 34.70 U/L and 1.99±SD 0.73 mmol/L, respectively). In contrast to that, concentrations of aspartate aminotransferase (AST) in cage-associated fish (87.63±SD 132.34 U/L) were higher than values noted for the control population (6.55±SD 5.90 U/L). URE and AST presented the main variables contributing to the discrimination between two analysed populations. One-way ANOSIM based on the blood parameters showed significant difference between saddled bream that fed around cages and those from the remote waters (R=0.697; P < 0.01). Hepatocytes of cage-associated fish contained large cytoplasmatic clear spaces indicating excessive accumulation of fat in the hepatocyte cytoplasm. All observed differences can be attributed to contrasting feeding behaviour of sampled populations but basic nutritional differences between them should be quantified in the future. Moreover, further research is necessary to detect their impact on the health status of the fish.     

Discriminant function model as a tool for classification of stratigraphically undefined radiolarian cherts in ophiolite zones

Two discriminant function models are constructed in order to distinguish major- and trace-element geochemical patterns characteristic for radiolarian cherts from the Zagorje–Mid-Transdanubian Zone ophiolite mélange of NW Croatia. The models are subsequently used to assign new samples from the adjacent magmatic–sedimentary complex extending from the Central Dinaridic Ophiolite Belt in NW Bosnia and thereby to test their applicability in similar cases when clear field relations are absent. In both models the first discriminant function explains the most part of the system variability. However, between the two, the trace-element model proves itself as a more helpful predictive tool presenting a straightforward example of correct classification of samples into three pre-defined groups (Triassic-basin, Triassic-slope and Jurassic radiolarian cherts). This result is extended further, with allocation of all samples from the test region into a single group (Jurassic) according to their trace-element geochemistry.     

Book reviews

Geographical, seasonal, and day-to-day variations in the vertical distributions of atmospheric density and temperature must be considered in the design and operation of reentry vehicles. This work is part of a continuing effort to compile, analyze, and present information on the distribution of the atmospheric temperature in a form suitable for use in the design and operation of aerospace vehicles. We have used temperature data obtained from rockets which are mostly based on the datasonde system throughout the decade 1969–1978. Profiles and the individual arrays of coefficients of correlation of the temperature at 20 km with temperature at higher altitudes up to 60 km are shown for each season for locations in the low, middle, and high latitudes.     

Book reviews

The possibility of the existence, around type-I supernovae, of dust shells which existed before a supernova outburst is considered. None have so far been detected observationally; and any dust around the progenitor radiating in the near infrared would evaporate at outburst. Far infrared observations of the two possible types of progenitor, R Coronae Borealis-type stars and dwarf novae, would be useful to indicate whether there is any dust around them which would survive a supernova outburst.     

Prominence motions and their implications for magnetic fields

Using results obtained in our earlier paper (Ballester and Kleczek, 1983) and the equipartition principle we attempt to calculate the lower limits of magnetic fields in three solar prominences. The values are then compared with the magnetic fields found by experimental methods. Furthermore, we have calculated by Ampère's law the lower limits of electric currents inside the conical surface where the knot's motion is located. The results obtained are compared with a few determinations of electric currents in prominences, that can be found in the bibliography. An attempt is made to use a three-currents system to explain the configuration of magnetic fields in solar prominences.