Blood serum characteristics of newborn pigs: comparison of unaffected pigs with pigs belonging to five mortality groups.

The blood serum levels of glucose, hemoglobin, insulin, cortisol, albumin, alpha-fetoprotein, alpha 2-macroglobulin f and s, alpha 2-antitrypsin inhibitor and alpha 1-protease inhibitor were determined at birth in 5 clinically and morphologically identified mortality groups of pigs. These were compared with the levels observed in unaffected, apparently normal newborn unsuckled pigs. The blood serum profile of the pigs in the stillborn intra partum, weak, splayleg and trauma groups, respectively, as well as that of clinically normal splayleg littermates, differed significantly from that of the unaffected pigs. This was especially true for the levels of hemoglobin and the two macroglobulins. The importance of placental insufficiency causing chronic episodes of hypoxia which ultimately lead to a disturbance in organ development in the etiology of the mortality groups is discussed.     

Wet belly in reindeer (Rangifer tarandus tarandus) in relation to body condition,body temperature and blood constituents

Wet belly, when the reindeer becomes wet over the lower parts of the thorax and abdomen, sometimes occurs in reindeer during feeding. In a feeding experiment, 11 out of 69 reindeer were affected by wet belly. The problem was first observed in 7 animals during a period of restricted feed intake. When the animals were then fed standard rations, 3 additional animals fed only silage, and 1 fed pellets and silage, became wet. Four animals died and 1 had to be euthanized. To investigate why reindeer developed wet belly, we compared data from healthy reindeer and reindeer affected by wet belly. Urea, plasma protein, glucose, insulin and cortisol were affected by restricted feed intake or by diet but did not generally differ between healthy reindeer and those with wet belly. The wet animals had low body temperature and the deaths occurred during a period of especially cold weather. Animals that died were emaciated and showed different signs of infections and stress. In a second experiment, with 20 reindeer, the feeding procedure of the most affected group in the first experiment was repeated, but none of the reindeer showed any signs of wet belly. The study shows that wet belly is not induced by any specific diet and may affect also lichen-fed reindeer. The fluid making the fur wet was proven to be of internal origin. Mortality was caused by emaciation, probably secondary to reduced energy intake caused by diseases and/or unsuitable feed.     

Effect of stress on myocardial cells and blood levels of catecholamines in normal and amygdalectomized pigs.

The effects of restraint stress on heart activity, blood catecholamines and the development of myocardial necrosis were studied in five unoperated and five unsuccessfully amygdalectomized (sham-operated) pigs and compared with six bilaterally amygdalectomized pigs. In the sham-operated and the nonoperated animals, restraint stress often provoked intense tachycardia, as well as considerable elevations of blood catecholamines, particularly noradrenaline, associated with more or less widespread foci of myocardial necrosis. In contrast, the same restraint produced only minor heart rate increase in the six completely amygdalectomized animals; their blood noradrenaline levels were significantly lower and no myocardial necrosis could be detected, either macro- or microscopically. The results indicate that the amygdaloid part of the limbic system and the sympathoadrenal system are of importance in the induction of myocardial necrosis often noted in pigs when exposed to situations of severe mental stress.     

Measurement of the uptake of linseed oil in pine by the use of an X-ray microdensitometry technique

Pine sapwood (Pinus sylvestris) was impregnated with linseed oil to three levels of uptake. The distribution of the penetrant was found by taking microdensity measurements of an impregnated sample and then using an ethanol extraction procedure to remove the linseed oil. A second set of X-ray measurements at identical locations in the same sample allowed the linseed oil to be indirectly mapped. An uneven distribution of linseed oil in the specimens with the lowest uptake (25% increase in weight) was seen as sharp gradients in the densitometry curves. With increased filling by the linseed oil, these gradients were gradually smoothed. Microstructural changes in specimens with high uptake were revealed using scanning electron microscopy. Through a combination of X-ray microdensitometry investigation and changes observed in the wood's mechanical properties and morphology, it was concluded that liquid flow during impregnation results in significant damage to the cell structure.     

Mechanical performance of linseed oil impregnated pine as correlated to the take-up level

 The mechanical performance of pine sapwood (pinus sylvestris), impregnated with linseed oil to different take-up levels, is evaluated using several test methods. SEM is used to study morphological changes following the impregnation procedure. The reduction of mechanical properties is attributed to a) localized cell wall damage in the ray region that facilitates longitudinal inter-cell split in L-R plane (macrocrack) initiation and propagation; b) submicroscopical cracking in the S1 sublayer that reduces the resistance to Mode I and Mode II inter-cell splitting at any location where the oil front has passed. Mechanical testing shows the following effect of the impregnation on failure a) the Mode I fracture toughness G _Ic in L-T and L-R planes, determined in DCB test, is significantly lowered with no significant difference in fracture resistance reduction in between planes; b) 3-point flexural test for specimen geometry leading to cracking in R-L and T-L planes show that the flexural strength as well as flexural modulus are reduced due to impregnation; c) 3-point flexural tests on longitudinal specimens used to determine the impregnation effect on longitudinal modulus E _L and shear moduli G _LT and G _LR , reveal only minor changes. Fracture surfaces in mechanical tests are analyzed using SEM, and differences are explained by described microdamage mechanisms. Received 10 August 1999     

Mechano-sorptive creep in wood fibres

In order to investigate the way in which fibre properties affect the mechano-sorptive creep phenomenon in paper, single wood fibres were exposed to tensile stresses at a constant humidity of 80% relative humidity (RH) and in a cyclic humidity environment varying between 80 and 30% RH. Contrary to earlier claims, it was demonstrated that single wood fibres exposed to a cyclic RH show a considerably higher creep than that corresponding to the highest RH experienced in the cycle, i.e., a mechano-sorptive behaviour. The creep strain rate at cyclic humidity was shown to be a function of the creep rate at constant climate, and to be an apparent linear function of the applied stress.     

Optimal upgrading of forest road networks: Scenario analysis vs. stochastic modelling

A two-stage stochastic model with binary choice in the first stage has been developed to optimise the upgrading of a real-world forest road network, geographically located in the middle of Sweden. We have compared the model with solutions to the same problem from deterministic scenario analysis. Upgrade policies can be achieved swiftly using both approaches, since the road network is of moderate size. However, a deterministic approach is considerably faster when larger problems are involved. The study here, furthermore, indicates that deterministic scenario analysis provides us with quick, near-optimal solutions to the stochastic model, which are of reasonable good quality. We conclude that the model used here is rather insensitive to uncertainty in critical period length, such as the length of spring thaw, at least when applied to the medium-sized problem presented here. Nevertheless, we strongly recommend the use of the stochastic model whenever possible, since the stochastic and deterministic solutions differ, due to the hedging effect in the stochastic solution.     

Abundance of arbuscular mycorrhizal fungi in relation to soil salinity around Lake Urmia in northern Iran analyzed by use of lipid biomarkers and microscopy

Saline soils around Lake Urmia in northern Iran constitute a stressed environment for plants and microbial communities, including arbuscular mycorrhizal (AM) fungi. Soil and root samples were collected from fields cultivated with the glycophytes Allium cepa L. and Medicago sativa L., and sites dominated by the halophyte Salicornia europaea L. Soil and root samples were analyzed for the AM fungal signature neutral lipid fatty acid (NLFA) 16:1ω5. The roots were also examined microscopically for mycorrhizal colonization. Each plant species was sampled across a salt gradient. Microscopic examination showed no AM fungal structures in the roots of S. europaea. The highest root colonization was recorded for M. sativa. The highest NLFA 16:1ω5 values were found in soil around M. sativa roots and the lowest in soil around S. europaea roots. We found evidence for stimulation of vesicle formation at moderate salinity levels in M. sativa, which is an indication of increased carbon allocation to mycorrhiza. On the other hand, we found a negative correlation between salinity and arbuscule formation in A. cepa, which may indicate a less functional symbiosis in saline soils.