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Summary Purification of a 40 kDa polypeptide from etiolated Sorghum bicolor mesocotyl that cross reacted with anti-Gα O . serum, was accomplished by chromatography of material released by freeze-thawing of mesocotyl microsomal fraction membranes on Af f i-gel Blue pseudo affinity resin followed by anion exchange hplc. Partial purification of 75 kDa and 29 kDa proteins that cross reacted with anti-Gao serum, and of a 65 kDa polypeptide that cross reacted with anti-GPα O 1 serum was accomplished by the same procedure. Protein microsequencing of the 40 kDa Gα O homologue and a 40.5 kDa protein yielded limited amino acid sequence that was consistent with their assignment as Gα subunits. Affinity labelling studies showed that the 40 kDa protein was labelled with [α 32 P]GTP but that the radiolabel could only be partially displaced with excess unlabelled GTP.

Several types of GTP-binding proteins exist in plant cells. These include the ras -related low-molecular-weight monomeric GTP-binding proteins and the multi-subunit group which more closely resembles members of the mammalian heterotrimeric G-protein family. Proteins belonging to both of these families are known to be involved in cell signalling events and have until recently been assumed to be associated predominantly with membranes. We have investigated the possibility that GTP-binding proteins in plants also can be associated with membrane-free carrot ( Daucus carota L.) cytoskeletons and nuclear matrices. Our results demonstrate that several low-molecular-weight GTP-binding proteins, and at least one G-protein α-subunit homologue, are associated with these cellular compartments.

The diferential equations governing two-phase flow through a porous medium are derived and the space discretization is carried out by the Galerkin finite element method. An examination of the eigenvalues of the resulting system follows in order to decide on a suitable stability criterion to be satisfied by the time-stepping algorithm. A class of time-stepping schemes is introduced and their behaviour when applied to a specific problem is analyzed. The aim is to achieve an adequate modelling of the water-oil interface and to preserve reasonable values of the capillary pressure. A technique to clustering the mesh around the interface is used to improved the modelling, and a boundary condition based on the relative mobilities of the two fiuids is imposed to enable the program to calculate the water-oil ratio after breakthrough. The effect of lumping the mass matrix is then examined with a view to reducting the surge in the values obtained for the capillary pressure. Finally an optimum method is suggested for use as a starting algorithm for more sophisticated time-stepping schemes.

Mature male and female rats were given ad libitum either control diet or low protein-high carbohydrate diets (starch or sucrose) for 4 weeks. Serum proteins, serum lipids and liver lipids were estimated. The adult females were more resistant to weight change than the males. Serum albumin concentrations in the females were higher than in the males. The males showed higher serum and liver lipid levels. There was a difference in serum protein and lipid levels between the males eating sucrose and those consuming starch, but no such differences were found in the females.

A method of increasing the efficiency of the construction of stiffness matrices in the finite element method is described. It considers how the efficiency of coding is affected by array referencing and shows how the restricted use of multisubscript arrays can improve the c.p.u. costs. Use is made of the large core storage areas usually available within finite element packages, together with the optimal use of backing store to keep cartesian derivative information which is sequentially loaded into buffers. An estimate of the efficiency of this method is also given which provides a criterion for its use when the global derivatives are known to be required on a given number of occasions during the core life of a program.

The analysis of multiphase flow in porous media is of considerable significance in the field of petroleum reservoir simulation, where accurate predictions of fluid flow are important in assessing the performance of oil and gas fields. The specific case of two-phase immiscible flow is considered by first deriving the governing nonlinear partial differential equations. The space discretization is then carried out making use of the additional versatility of the finite element method compared with originally used finite differences. By using a pair of dependent variables P and R , the bandwidth of the discrete space-continuous time equations may be reduced to increase significantly the speed of the algorithm. A discussion of time-stepping methods is followed by an application of the technique to a five-spot,an extraction pattern used in the field. The boundary conditions used to simulate this flow pattern are also discussed.

An analysis of multiphase flow through a compacting porous medium is investigated in this paper. The nonlinear partial differential equations governing the flow regimes are derived and a method of calculating the effective stress gradients is given. This method involves a local averaging technique to model the interaction of two immiscible fluid phases on a small volume of the deforming porous medium. The combined stress and flow problem is then solved using the finite element method where the flow is confined to a submesh of the whole region. A simulation is made of a typical vertical cross-section of the Forties Field.

We have studied the peripherally-produced pπ+π− system from the reaction K+p → K+p π+π− for pπ+π− masses less than 1.9 GeV/c2. Analysis of the angular distributions of the normal to the pππ decay plane and a model-dependent analysis of the Dalitz plot and decay angular distributions both show that more than one spin-parity state is present throughout the region. For pπ+π− masses less than 1.5 GeV/c2 JP in the Δπ system is predominantly 3− 2 while above 1.6 GeV /c J P = 5 2 + and 1 2 + are both significant while there is a substantial non-Δπ contribution at all masses. None of our Δπ amplitudes show clearly defined resonant behaviour.

We present an analysis of the K ππ system produced in 10 GeV/ c K + p interactions. We show that the low-mass enchancement between 1.2 and 1.4 GeV/ c 2 on the K ππ mass spectrum is predominantly 1 + throughout, give the relative amplitudes for the decay of this system into K ∗ (890) π and K ρ , and offer new evidence for the presence of two 1 + resonances in this mass region.

Data are presented on Λ production in 10 GeV/c K+p interactions. A low-mass enhancement is found in the ΛN system in quasi-three-body final states but the nature of this enhancement is not clear. The generalised Veneziano model is applied to the final state Λpp and a reggeised multi-peripheral model to the three- and four-body final states. In each case agreement with the data is only qualitative.

We report on a study of the L-meson in four-, five- and six-body final states from the interaction of K + mesons with protons at 10 GeV/ c . We find strong evidence for decay of the L-meson into K * (890)π and K * (890)ϱ as well as for decay into K * (1420)π. We also find evidence for decay into K * ω.

Relative accuracy of numerical quadrature rules when applied to the simulation of underground petroleum reservoirs by means of the finite element method is investigated. Fluid flow within the reservoir is calculated via the finite element method and the resulting deformation by the nucleus of strain technique. By analysing a simple problem it was found that the solution method was susceptible to changes in numerical quadrature for reservoirs that were positioned near the ground surface and that care is required when solving such problems due to the singularities occurring in the integrands which appear in the nucleus of strain approach.

The nutritional effects of feeding either sucrose or starch as components of a high carbohydrate low protein diet were studied and the effects of a combined oral contraceptive observed. Animals receiving the contraceptive had a greater weight loss. An inverse relationship between serum albumin and γ-globulin was demonstrated, but did not hold for rats on the sucrose diet receiving the ‘pill’. A marked increase in the liver lipid concentration was shown for the group receiving sucrose and the ‘pill’.

Summary Real-time ultrasonic scanning can be used to diagnose pregnancy and determine fetal numbers in sheep and has advantages over other approaches in terms of safety, accuracy and rapidity. Applied between 50 and 100 days of gestation the accuracy of diagnosis of pregnancy should be virtually 100%, and that of fetal number determination of the order of 96-98% or greater. Rates of scanning vary from 80 to 120 or more ewes per hour depending on expected litter size. The principles of ultrasound and the use and merits of linear-array and sector scanning instruments are discussed, and factors affecting image quality and hence accuracy are considered. The principal benefits of the use of the technique include the ability to relate feed inputs in late pregnancy to fetal numbers, thus improving the efficiency of use of feedstuffs. Feeding in relation to fetal numbers also offers a means of manipulating lamb birthweights and can lead to substantial reductions in levels of mortality of both lambs and ewes. The uptake of the technique by the sheep industry in the United Kingdom has been rapid, and it is estimated that the number of ewes scanned increased from about 1000 in 1983 to 2000000 in 1986. Accurate scanning demands a high degree of skill on the part of the operator, but the benefits of the technique to sheep production stem from the changes in management implemented on the basis of the scanning results.

During the early grazing season, when a high proportion of the lambs nutrient requirements are supplied by milk, high rates of growth can be achieved by sward management which maintains a constant surface height (3-5.5 cm) (Maxwell, Lloyd and Dickson, 1985). In late lactation, increasing herbage Intake rarely compensates for reduced milk supply and lamb growth rates are commonly lower than could be achieved with concentrate diets (Doney et al, 1984; Lloyd et al 1987). Lamb growth in this period may be related to increase or decrease of sward height (Alcock, Clark and Harvey, 1986; Maxwell, Lloyd and Dickson, 1985) or to changes in herbage growth rate (Doney, Smith, Sim and White, 1986). The present study investigated the effect on daily live-weight gain (DLWG) in weaned lambs of herbage growth rate (HGR) and pattern of sward height (SH) change when varied independently.