Heating and cooling rates and their effects upon heart rate in the angulate tortoise,Chersina angulate

The heating and cooling rates of adult Chersina angulata were investigated to ascertain whether these tortoises can physiologically alter their rates of heat exchange. In addition, heart rates were recorded to provide an insight into the control of heat exchange. C. angulata heats significantly faster than it cools. Heart rates increase with increasing body temperature, and for all body temperatures heart rates were greater during heating than during cooling. This suggests that the cardiovascular system plays a role in the heat exchange of the tortoises, but further study is required to completely understand the thermoregulatory process.     

Acoustic,mechanical and microstructural properties of extruded crisp bread

The aim of this work was to describe the texture and structure of crisp bread obtained with different extrusion parameters. The texture of different crisp bread samples was evaluated using a combination of acoustic and mechanical tests. The advantage of this measurement setup is the feasibility of simultaneous registering of the force–deformation characteristics, sounds (using an acoustic envelope detector coupled to the texture analyser with a microphone) as well as mechanical vibrations (registered using a piezoelectric sensor) generated during a penetration test. All analysed samples of bread were products with a crisp texture that emitted audible sounds with a significant intensity that could be registered with a microphone as well as with a contact method. Micro-CT cross-section images showed the highly porous structure of the crisp breads but variant 3 appeared to have thicker walls and larger cells than the other breads.     

Detection of residues of the coccidiostat diclazuril in poultry tissues by liquid chromatography-tandem mass spectrometry after withdrawal of medicated feed

A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the quantitative determination of diclazuril in poultry tissues and feed is presented. A simple clean up with an organic solvent was carried out. A reversed-phase C(18) column was used for the high-performance liquid chromatography (HPLC) to separate the analyte with a gradient of acetonitrile and water as mobile phase. The precursor ions produced by electrospray negative ionization were selected for collisional dissociation. Validation of the methods was performed based on Commission Decision 2002/657/EC (Off. J. Eur. Communities 2002, L221, 8-36). For the detection of diclazuril in poultry meat, the decision limit was found to be 0.5 microg/kg. An animal experiment was set up in which 70 chickens were held for 6 weeks. From day 22 until day 32, they were fed feed containing 730 microg/kg diclazuril. From day 33 until day 42, every day six chickens were slaughtered, and breast, thigh, and liver were analyzed. Average steady-state concentrations of 94, 135, and 722 microg/kg in breast, thigh, and liver were obtained, respectively. Nine days after withdrawal of the medicated feed, diclazuril was still present in the different sample types.     

Détermination de la courbe de dissociation standard de l''oxyhémoglobine du cheval et influence, sur cette courbe, de la température, du pH et du diphosphoglycérate.

The equine blood oxyhemoglobin dissociation curve has been traced in its entirety in standard conditions and the effects of temperature, pH and 2,3-diphosphoglycerate on this curve have been measured. When compared to that of human blood, the curve showed a higher oxygen affinity of hemoglobin (23.8 +/- 0.8 versus 26.6 mm Hg). The effect of the pH, expressed by d log P50/dpH, was found to be identical in man and horse (-0.47). The effect of temperature, however, expressed by d log P50/dT, proved to be lower in the horse (0.016 versus 0.024). The P50 showed an increase of 1 mm Hg each time 2,3-diphosphoglycerate was experiencing an elevation of 4 mumol/gHb in the horse. The results obtained from this experiment are intended for the replacement of the values related to the human blood which have been found to be somewhat inadequate for the horse blood, when the data of blood gases are given in algorithms.     

Cells, cytokines and other molecules associated with rejection of gastrointestinal nematode parasites

Infections with gastrointestinal nematodes represent a major problem for human health and animal health and production. The physical size of the parasite, its changing life-cycle stages and the relative inaccessibility to host cells pose unique challenges to the immune system, which has evolved specialized strategies for parasite control. This paper reviews the work performed in the authors' laboratories to identify components that are involved in the natural rejection response against ruminant gastrointestinal nematode parasites, in particular Haemonchus contortus in sheep. The results of these studies indicate that stage-specific antibodies act in concert with effector cells, in particular globular leukocytes (intraepithelial mast cells) and eosinophils, appropriately activated/primed by type 2 (T2) cytokines, to initiate different mechanisms of parasite expulsion and killing. In addition, other molecules, in particular carbohydrate binding galectins, may be involved in strengthening the final effector phase of the rejection response.     

Evidence on the response of Patagonian forage grasses to the mulching effect of recent tephra deposits in Argentina

In Patagonia, arid and semiarid lands are being affected both by inappropriate management practices, which are leading to degradation, and by volcanic activity, whose effects are still unclear. This study aimed to test whether superficial deposition of volcanic tephra could benefit two of the most prominent Patagonian forage grass species (Poa ligularis and Pappostipa speciosa var. speciosa). Pots with P. ligularis and P. speciosa were kept under wet (W) and dry (D) conditions in the presence (T+) or absence (T?) of tephra for 105 days, and then were all well-watered. We determined the effects of tephra on soil water retention and conservation, soil moisture content (% v/v), plant growth, stomatal conductance (gs), and gs recovery capacity. The water regime significantly affected both species performance and gs. The presence of tephra increased soil water conservation, soil moisture content in wet conditions, and P. ligularis gs in wet conditions, and decreased senescence in dry conditions (9% in P. ligularis and 16% in P. speciosa). The presence of tephra allowed roots to grow in 8/10 and 2/10 pots in W conditions for P. ligularis and P. speciosa, respectively, and in only 1/10 pots in D conditions, only for P. ligularis. Tephra was also associated with gs recovery after dry conditions. Poa ligularis was more positively affected by tephra than P. speciosa, probably because P. ligularis has higher phenotypic plasticity. The positive effects of tephra may increase the resilience and resistance of P. speciosa and P. ligularis to periods of water shortage.